ORGANIC ELECTROLUMINESCENT ELEMENT AND ELECTRONIC APPLIANCE

Abstract

An organic electroluminescence device includes an anode, a cathode, and an emitting layer disposed between the anode and the cathode. The emitting layer comprises a delayed fluorescent compound M2 having at least one deuterium atom and a compound M3 having at least one deuterium atom. A singlet energy S.sub.1(M2) of the compound M2 and a singlet energy S.sub.1(M3) of the compound M3 satisfy the relationship S.sub.1(M3)>S.sub.1(M2).

Claims

1. An organic electroluminescence device comprising: an anode; a cathode; and an emitting layer disposed between the anode and the cathode, wherein the emitting layer comprises: a delayed fluorescent compound M2 having at least one deuterium atom and a compound M3 having at least one deuterium atom, and a singlet energy S.sub.1(M2) of the compound M2 and a singlet energy S.sub.1(M3) of the compound M3 satisfy a relationship of a numerical formula (Numerical Formula 1) below,
S.sub.1(M3)>S.sub.1(M2)  (Numerical Formula 1).

2. The organic electroluminescence device according to claim 1, wherein: the emitting layer further comprises a fluorescent compound M1, and the singlet energy S.sub.1(M2) of the compound M2 and a singlet energy S.sub.1(M1) of the compound M1 satisfy a relationship of a numerical formula (Numerical Formula 2) below,
S.sub.1(M2)>S.sub.1(M1)  (Numerical Formula 2).

3. The organic electroluminescence device according to claim 1, wherein: the compound M3 comprises, in one molecule thereof, at least one of partial structures represented by formulae (31) to (48) below, when the compound M3 comprises a plurality of partial structures represented by the formula (31), a plurality of partial structures represented by the formula (32), a plurality of partial structures represented by the formula (33), and a plurality of partial structures represented by the formula (34), the plurality of partial structures represented by the formula (31) are the same or different, the plurality of partial structures represented by the formula (32) are the same or different, the plurality of partial structures represented by the formula (33) are the same or different, and the plurality of partial structures represented by the formula (34) are the same or different, ##STR00239## where, in the formula (31): A.sub.31 to A.sub.36 are each independently a nitrogen atom, CR.sub.31, or a carbon atom bonded to another atom or another structure in the molecule of the compound M3, at least one of A.sub.31 to A.sub.36 is a carbon atom bonded to another atom or another structure in the molecule of the compound M3, and each R.sub.31 is independently a hydrogen atom or a substituent, or at least one pair of pairs of adjacent ones of R.sub.31 are mutually bonded to form a ring, where, in the formula (32): A.sub.41 to A.sub.44 are each independently a nitrogen atom, CR.sub.32, or a carbon atom bonded to another atom or another structure in the molecule of the compound M3, each R.sub.32 is independently a hydrogen atom or a substituent, or at least one pair of pairs of adjacent ones of R.sub.32 are mutually bonded to form a ring, X.sub.30 is NR.sub.33, CR.sub.34R.sub.35, SiR.sub.36R.sub.37, an oxygen atom, a sulfur atom, a nitrogen atom bonded to another atom or another structure in the molecule of the compound M3, a carbon atom bonded to R.sub.38 and another atom or another structure in the molecule of the compound M3, or a silicon atom bonded to R.sub.39 and another atom or another structure in the molecule of the compound M3, at least one of carbon atoms in A.sub.41 to A.sub.44, a nitrogen atom in X.sub.30, a carbon atom in X.sub.30, or a silicon atom in X.sub.30 is bonded to another atom or another structure in the molecule of the compound M3, and R.sub.33 to R.sub.39 are each independently a hydrogen atom or a substituent, or at least one pair of a pair of adjacent R.sub.34 and R.sub.35 or a pair of adjacent R.sub.36 and R.sub.37 are mutually bonded to form a ring, where, in the formulae (33) and (34): R.sub.331 to R.sub.333 are each independently a hydrogen atom or a substituent, or a pair of adjacent R.sub.331 and R.sub.332 are mutually bonded to form a ring, where, in the formulae (31) to (34): R.sub.31 to R.sub.39 and R.sub.331 to R.sub.333 serving as the substituents are each independently a halogen atom, a cyano group, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 30 carbon atoms, a substituted or unsubstituted arylsilyl group having 6 to 60 ring carbon atoms, a substituted or unsubstituted arylphosphoryl group having 6 to 60 ring carbon atoms, a hydroxy group, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms, an amino group, a substituted or unsubstituted alkylamino group having 2 to 30 carbon atoms, a substituted or unsubstituted arylamino group having 6 to 60 ring carbon atoms, a thiol group, a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted germanium group, a substituted phosphine oxide group, a nitro group, a substituted or unsubstituted carbonyl group, or a substituted boryl group, a plurality of R.sub.31 are mutually the same or different, a plurality of R.sub.32 are mutually the same or different, and * is a bonding portion to another atom or another structure in the molecule of the compound M3.

4. The organic electroluminescence device according to claim 3, wherein the partial structure represented by the formula (31) is represented by any of groups represented by formulae (31a) to (31f) below, and monovalent or higher-valent residues derived from compounds represented by formulae (31g) to (31k), (31m), (31n), (31p), and (31q) below, ##STR00240## ##STR00241## ##STR00242## ##STR00243## ##STR00244## ##STR00245## where, in the formulae (31a) to (31f), Y.sub.12 to Y.sub.16 are each independently a nitrogen atom or CR.sub.31, each R.sub.31 independently represents the same as R.sub.31 in the formula (31), and * is a bonding portion to another atom or another structure in the molecule of the compound M3; where, in the formulae (31g) to (31k), (31m), (31n), and (31p), Y.sub.11 to Y.sub.14, Y.sub.17 to Y.sub.39, and Y.sub.70 to Y.sub.95 are each independently a nitrogen atom or CR.sub.31, or a carbon atom bonded to another atom or another structure in the molecule of the compound M3, each R.sub.31 independently represents the same as R.sub.31 in the formula (31), and at least one of Y.sub.11 to Y.sub.14, Y.sub.17 to Y.sub.39, or Y.sub.70 to Y.sub.95 is a carbon atom bonded to another atom or another structure in the molecule of the compound M3; where, in the formula (31q), Y.sub.11 to Y.sub.14 and Y.sub.21 to Y.sub.24 are each independently a nitrogen atom or CR.sub.31, or a carbon atom bonded to another atom or another structure in the molecule of the compound M3, each R.sub.31 independently represents the same as R.sub.31 in the formula (31), X.sub.32 and X.sub.33 each independently represent the same as X.sub.30 in the formula (32), and at least one of carbon atoms in Y.sub.11 to Y.sub.14, carbon atoms in Y.sub.21 to Y.sub.24, nitrogen atoms in X.sub.32 and X.sub.33, carbon atoms in X.sub.32 and X.sub.33, or silicon atoms in X.sub.32 and X.sub.33 is bonded to another atom or another structure in the molecule of the compound M3; and * is a bonding portion to another atom or another structure in the molecule of the compound M3.

5. The organic electroluminescence device according to claim 4, wherein in the formulae (31a) to (31k), (31m), (31n), (31p), and (31q), at least one of R.sub.31 in CR.sub.31 is a deuterium atom.

6. The organic electroluminescence device according to claim 3, wherein the partial structure represented by the formula (32) is represented by any of groups represented by formulae (32a) to (32f) below, and monovalent or higher-valent residues derived from compounds represented by formulae (32g) to (32k), (32m), (32n), and (32p) below, ##STR00246## where, in the formulae (32a) to (32f), Y.sub.410 to Y.sub.413 are each independently a nitrogen atom or CR.sub.32, each R.sub.32 independently represents the same as R.sub.32 in the formula (32), X.sub.30 represents the same as X.sub.30 in the formula (32), and * is a bonding portion to another atom or another structure in the molecule of the compound M3; where, in the formula (32g), Y.sub.410 to Y.sub.411 and Y.sub.45 to Y.sub.48 are each independently a nitrogen atom or CR.sub.32, or a carbon atom bonded to another atom or another structure in the molecule of the compound M3, each R.sub.32 independently represents the same as R.sub.32 in the formula (32), X.sub.30 represents the same as X.sub.30 in the formula (32), and at least one of carbon atoms in Y.sub.410 to Y.sub.411 and Y.sub.45 to Y.sub.48, a nitrogen atom in X.sub.30, a carbon atom in X.sub.30, or a silicon atom in X.sub.30 is bonded to another atom or another structure in the molecule of the compound M3; where, in the formula (32h), Y.sub.41 to Y.sub.48 are each independently a nitrogen atom or CR.sub.32, or a carbon atom bonded to another atom or another structure in the molecule of the compound M3, each R.sub.32 independently represents the same as R.sub.32 in the formula (32), X.sub.30 represents the same as X.sub.30 in the formula (32), and at least one of carbon atoms in Y.sub.41 to Y.sub.48, a nitrogen atom in X.sub.30, a carbon atom in X.sub.30, or a silicon atom in X.sub.30 is bonded to another atom or another structure in the molecule of the compound M3; and * is a bonding portion to another atom or another structure in the molecule of the compound M3, ##STR00247## ##STR00248## ##STR00249## ##STR00250## ##STR00251## ##STR00252## where, in the formulae (32i) to (32k), (32m), (32n), and (32p), Y.sub.41 to Y.sub.48 and Y.sub.61 to Y.sub.64 are each independently a nitrogen atom or CR.sub.32, or a carbon atom bonded to another atom or another structure in the molecule of the compound M3, each R.sub.32 independently represents the same as R.sub.32 in the formula (32), X.sub.30 and X.sub.31 each independently represent the same as X.sub.30 in the formula (32), and at least one of carbon atoms in Y.sub.41 to Y.sub.48 and Y.sub.61 to Y.sub.64, nitrogen atoms in X.sub.30 and X.sub.31, carbon atoms in X.sub.30 and X.sub.31, or silicon atoms in X.sub.30 and X.sub.31 is bonded to another atom or another structure in the molecule of the compound M3.

7. The organic electroluminescence device according to claim 6, wherein in the formulae (32a) to (32k), (32m), (32n), and (32p), at least one of R.sub.32 in CR.sub.32 is a deuterium atom.

8. The organic electroluminescence device according to claim 1, wherein the compound M3 comprises at least one group of a cyano group, an amino group, a substituted or unsubstituted alkylamino group having 2 to 30 carbon atoms, or a substituted or unsubstituted arylamino group having 6 to 60 ring carbon atoms, or comprises at least one monovalent or higher-valent residue derived from any of a substituted or unsubstituted benzene, a substituted or unsubstituted naphthalene, a substituted or unsubstituted indole, a substituted or unsubstituted carbazole, a substituted or unsubstituted dibenzofuran, a substituted or unsubstituted dibenzothiophene, a substituted or unsubstituted fluorene, a compound represented by a formula (36a) below, a substituted or unsubstituted triazine, a substituted or unsubstituted pyrimidine, a substituted or unsubstituted pyridine, a substituted or unsubstituted pyridazine, a substituted or unsubstituted pyrazine, a substituted or unsubstituted imidazole, a substituted or unsubstituted benzimidazole, a substituted or unsubstituted phenanthrene, a substituted or unsubstituted anthracene, a substituted or unsubstituted triphenylene, a substituted or unsubstituted chrysene, a substituted or unsubstituted fluoranthene, and a substituted or unsubstituted benzochrysene, ##STR00253## where, in the formula (36a): R.sub.36 to R.sub.38 are each independently a hydrogen atom or a substituent, or at least one pair of pairs of adjacent ones of R.sub.38 or a pair of R.sub.36 and R.sub.37 are mutually bonded to form a ring, R.sub.36 to R.sub.38 serving as the substituents are each independently a halogen atom, a cyano group, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 30 carbon atoms, a substituted or unsubstituted arylsilyl group having 6 to 60 ring carbon atoms, a substituted or unsubstituted arylphosphoryl group having 6 to 60 ring carbon atoms, a hydroxy group, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms, an amino group, a substituted or unsubstituted alkylamino group having 2 to 30 carbon atoms, a substituted or unsubstituted arylamino group having 6 to 60 ring carbon atoms, a thiol group, a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted germanium group, a substituted phosphine oxide group, a nitro group or a substituted or unsubstituted carbonyl group, and a plurality of R.sub.38 are mutually the same or different.

9. The organic electroluminescence device according to claim 8, wherein the compound M3 comprises a cyano group, or comprises at least one monovalent or higher-valent residue derived from any of a substituted or unsubstituted carbazole, a substituted or unsubstituted dibenzofuran, a substituted or unsubstituted dibenzothiophene, a substituted or unsubstituted fluorene, a compound represented by the formula (36a), a substituted or unsubstituted triazine, a substituted or unsubstituted pyrimidine, a substituted or unsubstituted pyridine, and a substituted or unsubstituted triphenylene.

10. The organic electroluminescence device according to claim 8, wherein the compound M3 comprises at least one monovalent or higher-valent residue derived from any of a substituted or unsubstituted carbazole, a substituted or unsubstituted dibenzofuran, a substituted or unsubstituted dibenzothiophene, a substituted or unsubstituted triazine, and a substituted or unsubstituted pyrimidine.

11. The organic electroluminescence device according to claim 8, wherein the compound M3 comprises a monovalent or higher-valent residue derived from a substituted or unsubstituted carbazole.

12. The organic electroluminescence device according to claim 8, wherein the compound M3 comprises a monovalent or higher-valent residue derived from a structure represented by a formula (3-100) below, ##STR00254## where, in the formula (3-100), D.sub.1 to D.sub.8 are each a deuterium atom, R.sub.310 is a substituent, and at least one of D.sub.1 to D.sub.8 or R.sub.310 is a single bond bonded to another atom or another structure in the molecule of the compound M3, and R.sub.310 serving as the substituent is a halogen atom, a cyano group, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 30 carbon atoms, a substituted or unsubstituted arylsilyl group having 6 to 60 ring carbon atoms, a substituted or unsubstituted arylphosphoryl group having 6 to 60 ring carbon atoms, a hydroxy group, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms, an amino group, a substituted or unsubstituted alkylamino group having 2 to 30 carbon atoms, a substituted or unsubstituted arylamino group having 6 to 60 ring carbon atoms, a thiol group, a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted germanium group, a substituted phosphine oxide group, a nitro group, a substituted or unsubstituted carbonyl group, or a substituted boryl group.

13. The organic electroluminescence device according to claim 1, wherein the compound M3 is a compound represented by a formula (301) or (302) below, ##STR00255## where, in the formula (301): Ar.sub.301 is a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycle having 5 to 30 ring atoms; m1 is 1, 2, 3, 4, 5, or 6; each R.sub.301 is an electron-donating group, and each R.sub.301 is bonded to an element forming Ar.sub.301; when m1 is 2 or more, a plurality of R.sub.301 are mutually the same or different; and Ar.sub.301 is not an electron-accepting aromatic hydrocarbon ring or heterocycle, and when Ar.sub.301 has a substituent, the substituent is not an electron-accepting group; and where, in the formula (302): Ar.sub.302 is a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycle having 5 to 30 ring atoms; n1 is 1, 2, 3, 4, 5, or 6; each R.sub.302 is an electron-accepting group, and each R.sub.302 is bonded to an element forming Ar.sub.302; when n1 is 2 or more, a plurality of R.sub.302 are mutually the same or different; and Ar.sub.302 is not an electron-donating aromatic hydrocarbon ring or heterocycle, and when Ar.sub.302 has a substituent, the substituent is not an electron-donating group.

14. The organic electroluminescence device according to claim 13, wherein each R.sub.301 in the formula (301) is independently a monovalent or higher-valent residue derived from any of compounds represented by formulae (D1) to (D6) and (D8) to (D10) below, or a group represented by a formula (D7) below, and each R.sub.302 in the formula (302) is independently a monovalent or higher-valent residue derived from any of compounds represented by formulae (A4) to (A18) and (A22) and (A23) below, or any of groups represented by formulae (A1) to (A3), (A19) to (A21), and (A24) below, ##STR00256## where, in the formula (D7), each * represents a bonding portion to an element forming Ar.sub.301, ##STR00257## ##STR00258## where, in the formula (A1), n.sub.A is 1, 2, or 3; where, in the formulae (A22) and (A23), X.sub.1 to X.sub.8 are each independently CR.sub.320 or a carbon atom bonded to another atom or another structure in the molecule of the compound M3, each R.sub.320 is independently a hydrogen atom or a substituent, or at least one pair of pairs of adjacent ones of R.sub.320 are mutually bonded to form a ring, and at least one of carbon atoms in X.sub.1 to X.sub.8 is bonded to an element forming Ar.sub.302; where, in the formula (A24), X.sub.1 to X.sub.8 are each independently a nitrogen atom or CR.sub.320, or a carbon atom bonded to an element forming Ar.sub.302, and each R.sub.320 is independently a hydrogen atom or a substituent, or at least one pair of pairs of adjacent ones of R.sub.320 are mutually bonded to form a ring; and where, in the formulae (A1) to (A3), (A19) to (A21), and (A24), each * represents a bonding portion to an element forming Ar.sub.302.

15. The organic electroluminescence device according to claim 1, wherein the compound M2 is a compound represented by a formula (2) or (22) below, ##STR00259## where, in the formula (2): n is 1, 2, 3 or 4; m is 1, 2, 3, or 4; q is 0, 1, 2, 3, or 4; m+n+q=6 is satisfied; CN is a cyano group; D.sub.1 is a group represented by a formula (2a), (2b), or (2c) below, and when a plurality of D.sub.1 are present, the plurality of D.sub.1 are mutually the same or different; Rx is a hydrogen atom or a substituent, or a pair of adjacent ones of Rx are mutually bonded to form a ring, and when a plurality of Rx are present, the plurality of Rx are mutually the same or different; each Rx as the substituent is independently a halogen atom, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted amino group, a substituted or unsubstituted carbonyl group, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 30 carbon atoms, or a substituted or unsubstituted arylsilyl group having 6 to 60 ring carbon atoms; and CN, D.sub.1, and Rx are each bonded to a carbon atom of a six-membered ring, ##STR00260## where, in the formula (2a): R.sub.1 to R.sub.8 are each independently a hydrogen atom or a substituent, or at least one pair of a pair of R.sub.1 and R.sub.2, a pair of R.sub.2 and R.sub.3, a pair of R.sub.3 and R.sub.4, a pair of R.sub.5 and R.sub.6, a pair of R.sub.6 and R.sub.7, or a pair of R.sub.7 and R.sub.8 are mutually bonded to form a ring; R.sub.1 to R.sub.8 as the substituents are each independently a halogen atom, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 30 carbon atoms, a substituted or unsubstituted arylsilyl group having 6 to 60 ring carbon atoms, a hydroxy group, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy halide group having 1 to 30 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms, a substituted or unsubstituted alkylamino group having 2 to 30 carbon atoms, a substituted or unsubstituted arylamino group having 6 to 60 ring carbon atoms, a thiol group, a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, or a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms; and * represents a bonding portion to a carbon atom of a benzene ring in the formula (2), ##STR00261## where, in the formula (2b): R.sub.21 to R.sub.28 are each independently a hydrogen atom or a substituent, or at least one pair of a pair of R.sub.21 and R.sub.22, a pair of R.sub.22 and R.sub.23, a pair of R.sub.23 and R.sub.24, a pair of R.sub.25 and R.sub.26, a pair of R.sub.26 and R.sub.27, or a pair of R.sub.27 and R.sub.28 are bonded to each other to form a ring; R.sub.21 to R.sub.28 serving as the substituents each independently represent the same as R.sub.1 to R.sub.8 in the formula (2a); A represents a cyclic structure represented by a formula (211) or (212) below, and the cyclic structure A is fused with adjacent cyclic structure(s) at any position(s); p is 1, 2, 3, or 4; when p is 2, 3, or 4, a plurality of cyclic structures A are mutually the same or different; and * represents a bonding portion to a carbon atom of a benzene ring in the formula (2), ##STR00262## where, in the formula (2c): R.sub.2001 to R.sub.2008 are each independently a hydrogen atom or a substituent, or at least one pair of a pair of R.sub.2001 and R.sub.2002, a pair of R.sub.2002 and R.sub.2003, a pair of R.sub.2003 and R.sub.2004, a pair of R.sub.2005 and R.sub.2006, a pair of R.sub.2006 and R.sub.2007, or a pair of R.sub.2007 and R.sub.2008 are bonded to each other to form a ring; R.sub.2001 to R.sub.2008 as the substituents each independently represent the same as R.sub.1 to R.sub.8 as the substituents in the formula (2a); B represents a cyclic structure represented by the formula (211) or (212), and the cyclic structure B is fused with adjacent cyclic structure(s) at any position(s); px is 1, 2, 3, or 4; when px is 2, 3, or 4, a plurality of cyclic structures B are mutually the same or different; C represents a cyclic structure represented by the formula (211) or (212), and the cyclic structure C is fused with adjacent cyclic structure(s) at any position(s); py is 1, 2, 3, or 4; when py is 2, 3, or 4, a plurality of cyclic structures C are mutually the same or different; and * represents a bonding portion to a carbon atom of a benzene ring in the formula (2), ##STR00263## where, in the formula (211): R.sub.2009 and R.sub.2010 are each independently a hydrogen atom or a substituent, or bonded to a part of an adjacent cyclic structure to form a ring, or a pair of R.sub.2009 and R.sub.2010 are mutually bonded to form a ring; where, in the formula (212): X.sub.201 is CR.sub.2011R.sub.2012, NR.sub.2013, a sulfur atom, or an oxygen atom, and R.sub.2011, R.sub.2012 and R.sub.2013 are each independently a hydrogen atom or a substituent, or R.sub.2011 and R.sub.2012 are mutually bonded to form a ring; and R.sub.2009, R.sub.2010, R.sub.2011, R.sub.2012, and R.sub.2013 serving as the substituents each independently represent the same as R.sub.1 to R.sub.8 serving as the substituents in the formula (2a), ##STR00264## where, in the formula (22): Ar.sub.1 is a group selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, a substituted silyl group, a cyano group, a nitro group, a carboxy group, and groups represented by formulae (1a) to (1j) below; Ar.sub.EWG is a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms that has one or more nitrogen atoms in a ring, or an aryl group having 6 to 30 ring carbon atoms that is substituted with one or more cyano groups; each Ar.sub.X is independently a hydrogen atom or a substituent, Ar.sub.X serving as the substituent being a group selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, a substituted silyl group, a cyano group, a nitro group, a carboxy group, and groups represented by the formulae (1a) to (1j) below; n is 0, 1, 2, 3, 4, or 5, and when n is 2, 3, 4, or 5, a plurality of Ar.sub.X are mutually the same or different; a ring (A) is a substituted or unsubstituted aromatic hydrocarbon ring or a substituted or unsubstituted heterocycle, the ring (A) is a five-membered ring, a six-membered ring, or a seven-membered ring, and Ar.sub.EWG, Ar.sub.1 and Ar.sub.X are each bonded to an element forming the ring (A); and at least one of Ar.sub.1 or Ar.sub.X is a group selected from the group consisting of groups represented by the formulae (1a) to (1j), ##STR00265## ##STR00266## ##STR00267## ##STR00268## where, in the formulae (1a) to (1j): X.sub.1 to X.sub.20 are each independently a nitrogen atom (N) or a carbon atom bonded to R.sub.A1 (C—R.sub.A1); where, in the formula (1b), one of X.sub.5 to X.sub.8 is a carbon atom bonded to one of X.sub.9 to X.sub.12, and one of X.sub.9 to X.sub.12 is a carbon atom bonded to one of X.sub.5 to X.sub.8; where, in the formula (1c), one of X.sub.5 to X.sub.8 is a carbon atom bonded to a nitrogen atom in a ring including A.sub.2; where, in the formula (1e), one of X.sub.5 to X.sub.8 and X.sub.18 is a carbon atom bonded to one of X.sub.9 to X.sub.12, and one of X.sub.9 to X.sub.12 is a carbon atom bonded to one of X.sub.5 to X.sub.8 and X.sub.18; where, in the formula (1f), one of X.sub.5 to X.sub.8 and X.sub.18 is a carbon atom bonded to one of X.sub.9 to X.sub.12 and X.sub.19, and one of X.sub.9 to X.sub.12 and X.sub.19 is a carbon atom bonded to one of X.sub.5 to X.sub.8 and X.sub.18; where, in the formula (1g), one of X.sub.5 to X.sub.8 is a carbon atom bonded to one of X.sub.9 to X.sub.12 and X.sub.19, and one of X.sub.9 to X.sub.12 and X.sub.19 is a carbon atom bonded to one of X.sub.5 to X.sub.8; where, in the formula (1h), one of X.sub.5 to X.sub.8 and X.sub.18 is a carbon atom bonded to a nitrogen atom in a ring including A.sub.2; where, in the formula (1i), one of X.sub.5 to X.sub.8 and X.sub.18 is a carbon atom bonded to a nitrogen atom linking a ring including X.sub.9 to X.sub.12 and X.sub.19 with a ring including X.sub.13 to X.sub.16 and X.sub.20; where, in the formula (1j): one of X.sub.5 to X.sub.8 is a carbon atom bonded to a nitrogen atom linking a ring including X.sub.9 to X.sub.12 and X.sub.19 with a ring including X.sub.13 to X.sub.16 and X.sub.20; each R.sub.A1 is independently a hydrogen atom or a substituent, or at least one pair of pairs of a plurality of R.sub.A1 are mutually directly bonded to form a ring or are bonded through a hetero atom to form a ring; R.sub.A1 as the substituent is a group selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, a substituted silyl group, a cyano group, a nitro group, and a carboxy group; and a plurality of R.sub.A1 serving as the substituents are mutually the same or different; where, in the formulae (1a) to (1j), * represents a bonding portion to the ring (A); where, in the formulae (1a) to (1j): A.sub.1 and A.sub.2 are each independently a single bond, an oxygen atom (O), a sulfur atom (S), C(R.sub.2021)(R.sub.2022), Si(R.sub.2023)(R.sub.2024), C(═O), S(═O), SO.sub.2, or N(R.sub.2025); R.sub.2021 to R.sub.2025 are each independently a hydrogen atom or a substituent, and R.sub.2021 to R.sub.2025 serving as the substituents are each independently a group selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, a substituted silyl group, a cyano group, a nitro group, and a carboxy group; and where, in the formulae (1a) to (1j), Ara is a group selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, and a substituted silyl group.

16. The organic electroluminescence device according to claim 15, wherein D.sub.1 is any one of groups represented by formulae (D-21) to (D-37) below, ##STR00269## where, in the formulae (D-21) to (D-25): R.sub.171 to R.sub.200 and R.sub.71 to R.sub.90 are each independently a hydrogen atom or a substituent, or at least one pair of the following are mutually bonded to form a ring: a pair of R.sub.171 and R.sub.172, a pair of R.sub.172 and R.sub.173, a pair of R.sub.173 and R.sub.174, a pair of R.sub.174 and R.sub.175, a pair of R.sub.175 and R.sub.176, a pair of R.sub.177 and R.sub.178, a pair of R.sub.178 and R.sub.179, a pair of R.sub.179 and R.sub.180, a pair of R.sub.181 and R.sub.182, a pair of R.sub.182 and R.sub.183, a pair of R.sub.183 and R.sub.184, a pair of R.sub.185 and R.sub.186, a pair of R.sub.186 and R.sub.187, a pair of R.sub.187 and R.sub.188, a pair of R.sub.188 and R.sub.189, a pair of R.sub.189 and R.sub.190, a pair of R.sub.191 and R.sub.192, a pair of R.sub.192 and R.sub.193, a pair of R.sub.193 and R.sub.194, a pair of R.sub.194 and R.sub.195, a pair of R.sub.195 and R.sub.196, a pair of R.sub.197 and R.sub.198, a pair of R.sub.198 and R.sub.199, a pair of R.sub.199 and R.sub.200, a pair of R.sub.71 and R.sub.72, a pair of R.sub.72 and R.sub.73, a pair of R.sub.73 and R.sub.74, a pair of R.sub.75 and R.sub.76, a pair of R.sub.76 and R.sub.77, a pair of R.sub.77 and R.sub.78, a pair of R.sub.79 and R.sub.80, a pair of R.sub.80 and R.sub.81, or a pair of R.sub.81 and R.sub.82; R.sub.171 to R.sub.200 and R.sub.71 to R.sub.90 serving as the substituents are each independently a halogen atom, a substituted or unsubstituted aryl group having 6 to 14 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 14 ring atoms, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 6 carbon atoms, a hydroxy group, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy halide group having 1 to 6 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 14 ring carbon atoms, a substituted or unsubstituted alkylamino group having 2 to 12 carbon atoms, a thiol group, a substituted or unsubstituted alkylthio group having 1 to 6 carbon atoms, or a substituted or unsubstituted arylthio group having 6 to 14 ring carbon atoms; and * represents a bonding portion to a carbon atom of a benzene ring in the formula (2), ##STR00270## ##STR00271## where, in the formulae (D-26) to (D-31): R.sub.11 to R.sub.16 are each a substituent, and R.sub.101 to R.sub.150 and R.sub.61 to R.sub.70 are each independently a hydrogen atom or a substituent, or at least one pair of the following are mutually bonded to form a ring: a pair of R.sub.101 and R.sub.102, a pair of R.sub.102 and R.sub.103, a pair of R.sub.103 and R.sub.104, a pair of R.sub.105 and R.sub.106, a pair of R.sub.107 and R.sub.108, a pair of R.sub.108 and R.sub.109, a pair of R.sub.109 and R.sub.110, a pair of R.sub.111 and R.sub.112, a pair of R.sub.112 and R.sub.113, a pair of R.sub.113 and R.sub.114, a pair of R.sub.116 and R.sub.17, a pair of R.sub.17 and R.sub.118, a pair of R.sub.118 and R.sub.119, a pair of R.sub.121 and R.sub.122, a pair of R.sub.122 and R.sub.123, a pair of R.sub.123 and R.sub.124, a pair of R.sub.126 and R.sub.127, a pair of R.sub.127 and R.sub.128, a pair of R.sub.128 and R.sub.129, a pair of R.sub.131 and R.sub.132, a pair of R.sub.132 and R.sub.133, a pair of R.sub.133 and R.sub.134, a pair of R.sub.135 and R.sub.136, a pair of R.sub.136 and R.sub.137, a pair of R.sub.137 and R.sub.138, a pair of R.sub.139 and R.sub.140, a pair of R.sub.141 and R.sub.142, a pair of R.sub.142 and R.sub.143, a pair of R.sub.143 and R.sub.144, a pair of R.sub.145 and R.sub.146, a pair of R.sub.146 and R.sub.147, a pair of R.sub.147 and R.sub.148, a pair of R.sub.149 and R.sub.150, a pair of R.sub.61 and R.sub.62, a pair of R.sub.62 and R.sub.63, a pair of R.sub.63 and R.sub.64, a pair of R.sub.65 and R.sub.66, a pair of R.sub.67 and R.sub.68, a pair of R.sub.68 and R.sub.69, or a pair of R.sub.69 and R.sub.70; R.sub.101 to R.sub.150 and R.sub.61 to R.sub.70 as the substituents are each independently a substituted or unsubstituted aryl group having 6 to 14 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 14 ring atoms, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 6 carbon atoms, a hydroxy group, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 14 ring carbon atoms, a substituted or unsubstituted arylamino group having 6 to 28 ring carbon atoms, a substituted or unsubstituted alkylamino group having 2 to 12 carbon atoms, a thiol group, a substituted or unsubstituted alkylthio group having 1 to 6 carbon atoms, or a substituted or unsubstituted arylthio group having 6 to 14 ring carbon atoms; R.sub.11 to R.sub.16 as the substituents are each independently a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 14 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 14 ring atoms, a substituted or unsubstituted alkylsilyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 14 ring carbon atoms, a substituted or unsubstituted alkylamino group having 2 to 12 carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 6 carbon atoms, or a substituted or unsubstituted arylthio group having 6 to 14 ring carbon atoms; and * represents a bonding portion to a carbon atom of a benzene ring in the formula (2), ##STR00272## ##STR00273## where, in the formulae (D-32) to (D-37): X.sub.1 to X.sub.6 are each independently an oxygen atom, a sulfur atom, or CR.sub.151R.sub.152; R.sub.151 and R.sub.152 are each independently a hydrogen atom or a substituent, or R.sub.151 and R.sub.152 are bonded to each other to form a ring; R.sub.201 to R.sub.260 are each independently a hydrogen atom or a substituent, or at least one pair of a pair of R.sub.201 and R.sub.202, a pair of R.sub.202 and R.sub.203, a pair of R.sub.203 and R.sub.204, a pair of R.sub.205 and R.sub.246, a pair of R.sub.247 and R.sub.248, a pair of R.sub.248 and R.sub.249, a pair of R.sub.249 and R.sub.217, a pair of R.sub.211 and R.sub.212, a pair of R.sub.212 and R.sub.213, a pair of R.sub.213 and R.sub.214, a pair of R.sub.216 and R.sub.217, a pair of R.sub.217 and R.sub.218, a pair of R.sub.218 and R.sub.219, a pair of R.sub.221 and R.sub.222, a pair of R.sub.222 and R.sub.223, a pair of R.sub.223 and R.sub.224, a pair of R.sub.226 and R.sub.227, a pair of R.sub.227 and R.sub.228, a pair of R.sub.228 and R.sub.229, a pair of R.sub.231 and R.sub.232, a pair of R.sub.232 and R.sub.233, a pair of R.sub.233 and R.sub.234, a pair of R.sub.235 and R.sub.236, a pair of R.sub.236 and R.sub.237, a pair of R.sub.237 and R.sub.238, a pair of R.sub.239 and R.sub.240, a pair of R.sub.241 and R.sub.242, a pair of R.sub.242 and R.sub.243, a pair of R.sub.243 and R.sub.244, a pair of R.sub.245 and R.sub.246, a pair of R.sub.246 and R.sub.247, a pair of R.sub.247 and R.sub.248, a pair of R.sub.249 and R.sub.250, a pair of R.sub.251 and R.sub.252, a pair of R.sub.252 and R.sub.253, a pair of R.sub.253 and R.sub.254, a pair of R.sub.255 and R.sub.256, a pair of R.sub.257 and R.sub.258, a pair of R.sub.258 and R.sub.259, or a pair of R.sub.259 and R.sub.260 are bonded to each other to form a ring; R.sub.151, R.sub.152, and R.sub.201 to R.sub.260 serving as the substituents are each independently a halogen atom, a substituted or unsubstituted aryl group having 6 to 14 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 14 ring atoms, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 6 carbon atoms, a hydroxy group, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy halide group having 1 to 6 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 14 ring carbon atoms, a substituted or unsubstituted arylamino group having 6 to 28 ring carbon atoms, a substituted or unsubstituted alkylamino group having 2 to 12 carbon atoms, a thiol group, a substituted or unsubstituted alkylthio group having 1 to 6 carbon atoms, or a substituted or unsubstituted arylthio group having 6 to 14 ring carbon atoms; and * represents a bonding portion to a carbon atom of a benzene ring in the formula (2).

17. The organic electroluminescence device according to claim 16, wherein at least one of R.sub.61 to R.sub.90, R.sub.101 to R.sub.152, or R.sub.171 to R.sub.260 is a deuterium atom.

18. The organic electroluminescence device according to claim 1, wherein a difference ΔST(M3) between the singlet energy S.sub.1(M3) of the compound M3 and an energy gap T.sub.77K(M3) at 77K of the compound M3 satisfies a relationship of a numerical formula (Numerical Formula 3) below,
ΔST(M3)=S.sub.1(M3)−T.sub.77K(M3)>0.35 eV  (Numerical Formula 3).

19. The organic electroluminescence device according to claim 1, further comprising: between the cathode and the emitting layer, an electron transporting zone that comprises one or more organic layers.

20. The organic electroluminescence device according to claim 19, wherein the electron transporting zone comprises a plurality of organic layers.

21. The organic electroluminescence device according to claim 19, further comprising: between the anode and the emitting layer, a hole transporting zone that comprises one or more organic layers.

22. The organic electroluminescence device according to claim 21, wherein the hole transporting zone comprises a plurality of organic layers.

23. The organic electroluminescence device according to claim 19, wherein at least one organic layer in the electron transporting zone comprises a compound represented by a formula (E1) below, ##STR00274## where, in the formula (E1): X.sub.51 to X.sub.56 are each independently a nitrogen atom or CR.sub.50, or at least one pair of pairs of adjacent ones of R.sub.50 are mutually bonded to form a ring; two or three of X.sub.51 to X.sub.56 are each a nitrogen atom; each R.sub.50 is independently a hydrogen atom or a substituent; each R.sub.50 serving as the substituent is independently a halogen atom, a cyano group, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 30 carbon atoms, a substituted or unsubstituted arylsilyl group having 6 to 60 ring carbon atoms, a substituted or unsubstituted arylphosphoryl group having 6 to 60 ring carbon atoms, a hydroxy group, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms, an amino group, a substituted or unsubstituted alkylamino group having 2 to 30 carbon atoms, a substituted or unsubstituted arylamino group having 6 to 60 ring carbon atoms, a thiol group, a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted germanium group, a substituted phosphine oxide group, a nitro group, a substituted or unsubstituted carbonyl group, or a substituted boryl group; and a plurality of R.sub.50 are mutually the same or different.

24. The organic electroluminescence device according to claim 23, wherein: the organic layers in the electron transporting zone comprise a first layer adjacent to the emitting layer, and the first layer comprises a compound represented by the formula (E1).

25. The organic electroluminescence device according to claim 23, wherein the compound represented by the formula (E1) is a compound represented by a formula (E11) or (E12) below, ##STR00275## where, in the formula (E11), R.sub.51, R.sub.52, R.sub.54, and R.sub.56 each independently represent the same as R.sub.50 in CR.sub.50 in the formula (E1); and where, in the formula (E12), R.sub.52, R.sub.54, and R.sub.56 each independently represent the same as R.sub.50 in CR.sub.50 in the formula (E1).

26. An electronic device comprising the organic electroluminescence device according to claim 1.

Description

BRIEF DESCRIPTION OF DRAWING(S)

[0014] FIG. 1 schematically shows an exemplary arrangement of an organic electroluminescence device according to a first exemplary embodiment of the invention.

[0015] FIG. 2 schematically shows a device of measuring transient PL.

[0016] FIG. 3 shows an example of a decay curve of the transient PL.

[0017] FIG. 4 shows a relationship in energy level and energy transfer between a compound M3 and a compound M2 in an emitting layer of an exemplary organic electroluminescence device according to the first exemplary embodiment of the invention.

[0018] FIG. 5 shows a relationship in energy level and energy transfer between a compound M3, a compound M2, and a compound M1 in an emitting layer of an exemplary organic electroluminescence device according to a second exemplary embodiment of the invention.

DESCRIPTION OF EMBODIMENT(S)

First Exemplary Embodiment

[0019] An arrangement of an organic EL device according to a first exemplary embodiment of the invention will be described below.

[0020] The organic EL device includes an anode, a cathode, and at least one organic layer between the anode and the cathode. This organic layer includes at least one layer formed of an organic compound. Alternatively, the organic layer includes a plurality of layers formed of an organic compound(s). The organic layer may further include an inorganic compound. In the organic EL device of the exemplary embodiment, at least one of the organic layer(s) is an emitting layer. Accordingly, the organic layer may consist of a single emitting layer or, alternatively, may further include at least one layer usable in organic EL devices. Examples of the layer usable in the organic EL device, which are not particularly limited, include at least one layer selected from the group consisting of a hole injecting layer, hole transporting layer, electron injecting layer, electron transporting layer, and blocking layer.

[0021] The organic EL device of the exemplary embodiment includes an emitting layer between the anode and the cathode.

[0022] FIG. 1 schematically shows an exemplary arrangement of an organic EL device according to the first exemplary embodiment.

[0023] An organic EL device 1 includes a light-transmissive substrate 2, an anode 3, a cathode 4, and an organic layer 10 provided between the anode 3 and the cathode 4. The organic layer 10 includes a hole injecting layer 6, a hole transporting layer 7, an emitting layer 5, an electron transporting layer 8, and an electron injecting layer 9, which are sequentially laminated on the anode 3.

[0024] An organic layer between the cathode 4 and the emitting layer 5 corresponds to an electron transporting zone. The electron transporting zone includes, for instance, at least one layer selected from the group consisting of an electron injecting layer, an electron transporting layer, and a hole blocking layer.

[0025] In the case of FIG. 1, the electron transporting zone includes the electron transporting layer 8 and the electron injecting layer 9. The electron transporting layer 8 is adjacent to the emitting layer 5.

[0026] An organic layer between the anode 3 and the emitting layer 5 corresponds to a hole transporting zone. The hole transporting zone includes, for instance, at least one layer selected from the group consisting of a hole injecting layer, a hole transporting layer, and an electron blocking layer.

[0027] In the case of FIG. 1, the hole transporting zone includes the hole injecting layer 6 and the hole transporting layer 7. The hole transporting layer 7 is adjacent to the emitting layer 5.

[0028] In an arrangement of the exemplary embodiment, the emitting layer may contain a metal complex.

[0029] In an arrangement of the exemplary embodiment, it is preferable that the emitting layer does not contain a phosphorescent material (dopant material).

[0030] In an arrangement of the exemplary embodiment, it is preferable that the emitting layer does not contain a heavy-metal complex and a phosphorescent rare-earth metal complex. Examples of the heavy-metal complex herein include iridium complex, osmium complex, and platinum complex.

[0031] In an arrangement of the exemplary embodiment, it is also preferable that the emitting layer does not contain a metal complex.

[0032] In the organic EL device according to the exemplary embodiment, the emitting layer contains a delayed fluorescent compound M2 having at least one deuterium atom and a compound M3 having at least one deuterium atom.

[0033] In the exemplary embodiment, the compound M2 is preferably a dopant material (which may be referred to as a guest material, an emitter, or a luminescent material), and the compound M3 is preferably a host material (which may be referred to as a matrix material).

[0034] Patent Literature 1 discloses that an organic EL device in which a deuterated TADF material is contained in an emitting layer has an improved lifetime. TADF materials use the inverse intersystem crossing from a triplet exciton to a singlet exciton and thus is present as an unstable exciton for a long time. Thus, the device lifetime of the organic EL device described in Patent Literature 1 is considered to be improved by replacing a C—H bond in a TADF material with a more stable C-D bond. It should be noted that D represents a deuterium atom.

[0035] On the other hand, since a host material contained in the emitting layer together with a TADF material has a large energy gap, the host material is less likely to absorb energy from the TADF material and is less likely to be in an unstable excited state. Therefore, even if the host material used together with the TADF material is deuterated, probably, the deuteration is less likely to contribute to the improvement in the device lifetime, and an example of such an improvement in the device lifetime has also not been reported. However, the inventors of the invention considered that a host material may also have a reduced energy gap and may be in an unstable excited state if the host material is in a radical cation state in which a hole has been injected or in a radical anion state in which an electron has been injected.

[0036] As a result of intensive studies, the inventors of the invention have found that the device lifetime can be improved by incorporating a deuterated host material in an emitting layer together with a TADF material (deuterated or non-deuterated TADF material). Furthermore, the inventors of the invention have found that the device lifetime can be significantly improved by deuterating not only the host material but also the TADF material, thereby completing an organic EL device according to the present disclosure.

[0037] According to the exemplary embodiment, an organic EL device having a long lifetime is provided by incorporating, in an emitting layer, a delayed fluorescent compound M2 having at least one deuterium atom (deuterated TADF material) and a compound M3 having at least one deuterium atom (deuterated host material).

[0038] Further, according to the exemplary embodiment, a high-performance organic EL device is achievable.

[0039] High performance means at least one of luminous efficiency, device lifetime, drive voltage, or luminance is improved.

[0040] Thus, according to the exemplary embodiment, in addition to the device lifetime, at least one of luminous efficiency, drive voltage, or luminance is expected to be improved.

[0041] Patent Literature 2 discloses an organic EL device in which a deuterated host material is contained in an emitting layer. However, the deuterated host material described in Patent Literature 2 has an aza-dibenzofuran ring. Such a host material having an aza-dibenzofuran ring cannot sufficiently contribute to an improvement in the device lifetime in some cases when used in combination with a TADF material. This is probably because a C—H bond adjacent to a nitrogen atom in the aza-dibenzofuran ring has higher acidity than a C—H bond adjacent to a carbon atom and thus is more likely to be broken.

[0042] For the same reason, a host material having an aza-dibenzothiophene ring also cannot sufficiently contribute to an improvement in the device lifetime in some cases when used in combination with a TADF material.

[0043] Accordingly, from the viewpoint of further improving the device lifetime, the compound M3 used in the exemplary embodiment is preferably, as a host material, a compound that does not have an aza-dibenzofuran ring or an aza-dibenzothiophene ring.

[0044] That is, it is preferable that the compound M3 is not a compound having a partial structure represented by a formula (1C) or (2C) below.

[0045] The compound having a partial structure represented by the formula (1C) is a compound having an aza-dibenzofuran ring.

[0046] The compound having a partial structure represented by the formula (2C) is a compound having an aza-dibenzothiophene ring.

##STR00001##

[0047] In the formulae (1C) and (2C):

[0048] Y.sub.41 to Y.sub.48 are each independently a nitrogen atom or CR, or a carbon atom bonded to another atom or another structure in a molecule of the compound M3;

[0049] at least one of Y.sub.41 to Y.sub.48 is a nitrogen atom, and at least one of Y.sub.41 to Y.sub.48 is a carbon atom bonded to another atom or another structure in the molecule of the compound M3;

[0050] each R is independently a hydrogen atom or a substituent; and

[0051] a plurality of R are mutually the same or different.

[0052] When R is a substituent, the substituent may be, for instance, the same group as R.sub.31 in the formula (31). A plurality of R are the same or different.

Emitting Layer

Compound M3 (Deuterated Compound M3)

[0053] The compound M3 may be a thermally activated delayed fluorescent compound or a compound exhibiting no thermally activated delayed fluorescence. However, the compound M3 is preferably a compound exhibiting no thermally activated delayed fluorescence.

[0054] Herein, the “compound M3 having at least one deuterium atom” refers to a compound in which the hydrogen atoms in the compound M3 are not composed only of protium atoms.

[0055] In the following description, a “compound M3 having at least one deuterium atom” may be referred to as a “deuterated compound M3”. A compound in which all hydrogen atoms in the compound M3 are protium atoms may be referred to as a “non-deuterated compound m3”.

[0056] In the exemplary embodiment, a content ratio of the non-deuterated compound m3 relative to the total of the deuterated compound M3 and the non-deuterated compound m3 in the emitting layer is 99% by mole or less. The content ratio of the non-deuterated compound m3 is examined by mass spectrometry.

[0057] In the organic EL device according to the exemplary embodiment, a content ratio of the deuterated compound M3 relative to the total of the deuterated compound M3 and the non-deuterated compound m3 in the emitting layer is preferably 30% by mole or more, 50% by mole or more, 70% by mole or more, 90% by mole or more, 95% by mole or more, 99% by mole or more, or 100% by mole.

[0058] In the exemplary embodiment, it is also preferable that deuterium atoms account for 10% or more of the total number of hydrogen atoms in the compound M3, deuterium atoms account for 20% or more thereof, deuterium atoms account for 30% or more thereof, deuterium atoms account for 40% or more thereof, deuterium atoms account for 50% or more thereof, deuterium atoms account for 60% or more thereof, deuterium atoms account for 70% or more thereof, and deuterium atoms account for 80% or more thereof.

Method for Checking Whether Deuterium Atom is Included in Compound M3 and Method for Specifying Bonding Position of Deuterium Atom in Compound M3

[0059] Whether a deuterium atom is included in the compound M3 is checked by mass spectrometry or .sup.1H-NMR spectrometry. The bonding position of the deuterium atom in the compound M3 is specified by .sup.1H-NMR spectrometry.

[0060] The details are as follows. Mass spectrometry is performed on a target compound. When a molecular weight of the target compound is increased by, for example, one as compared with a related compound in which all the hydrogen atoms in the target compound are replaced by protium atoms, it is determined that the target compound includes a deuterium atom. Further, since a signal of a deuterium atom does not appear in .sup.1H-NMR spectrometry, the number of deuterium atoms in the molecule is determined by an integral value obtained by performing .sup.1H-NMR spectrometry on the target compound. Furthermore, the bonding position of the deuterium atom is determined by conducting .sup.1H-NMR spectrometry on the target compound to perform signal assignment.

Partial Structures Represented by Formulae (31) to (48)

[0061] In the exemplary embodiment, the compound M3 preferably includes, in one molecule thereof, at least one of partial structures represented by formulae (31) to (48) below.

[0062] When the compound M3 has a plurality of partial structures represented by the formula (31), a plurality of partial structures represented by the formula (32), a plurality of partial structures represented by the formula (33), and a plurality of partial structures represented by the formula (34) below, the plurality of partial structures represented by the formula (31) are the same or different, the plurality of partial structures represented by the formula (32) are the same or different, the plurality of partial structures represented by the formula (33) are the same or different, and the plurality of partial structures represented by the formula (34) are the same or different.

##STR00002## ##STR00003##

[0063] In the formula (31):

[0064] A.sub.31 to A.sub.36 are each independently a nitrogen atom, CR.sub.31, or a carbon atom bonded to another atom or another structure in the molecule of the compound M3,

[0065] at least one of A.sub.31 to A.sub.36 is a carbon atom bonded to another atom or another structure in the molecule of the compound M3, and

[0066] each R.sub.31 is independently a hydrogen atom or a substituent, or at least one pair of pairs of adjacent ones of R.sub.31 are mutually bonded to form a ring;

[0067] In the formula (32):

[0068] A.sub.41 to A.sub.44 are each independently a nitrogen atom, CR.sub.32, or a carbon atom bonded to another atom or another structure in the molecule of the compound M3,

[0069] each R.sub.32 is independently a hydrogen atom or a substituent, or at least one pair of pairs of adjacent ones of R.sub.32 are mutually bonded to form a ring,

[0070] X.sub.30 is NR.sub.33, CR.sub.34R.sub.35, SiR.sub.36R.sub.37, an oxygen atom, a sulfur atom, a nitrogen atom bonded to another atom or another structure in the molecule of the compound M3, a carbon atom bonded to R.sub.38 and another atom or another structure in the molecule of the compound M3, or a silicon atom bonded to R.sub.39 and another atom or another structure in the molecule of the compound M3,

[0071] at least one of carbon atoms in A.sub.41 to A.sub.44, a nitrogen atom in X.sub.30, a carbon atom in X.sub.30, or a silicon atom in X.sub.30 is bonded to another atom or another structure in the molecule of the compound M3, and

[0072] R.sub.33 to R.sub.39 are each independently a hydrogen atom or a substituent, or at least one pair of a pair of adjacent R.sub.34 and R.sub.35 or a pair of adjacent R.sub.36 and R.sub.37 are mutually bonded to form a ring;

[0073] in the formulae (33) and (34),

[0074] R.sub.331 to R.sub.333 are each independently a hydrogen atom or a substituent, or a pair of adjacent R.sub.331 and R.sub.332 are mutually bonded to form a ring;

[0075] in the formulae (31) to (34),

[0076] R.sub.31 to R.sub.39 and R.sub.331 to R.sub.333 serving as the substituents are each independently a halogen atom, a cyano group, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 30 carbon atoms, a substituted or unsubstituted arylsilyl group having 6 to 60 ring carbon atoms, a substituted or unsubstituted arylphosphoryl group having 6 to 60 ring carbon atoms, a hydroxy group, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms, an amino group, a substituted or unsubstituted alkylamino group having 2 to 30 carbon atoms, a substituted or unsubstituted arylamino group having 6 to 60 ring carbon atoms, a thiol group, a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted germanium group, a substituted phosphine oxide group, a nitro group, a substituted or unsubstituted carbonyl group, or a substituted boryl group,

[0077] a plurality of R.sub.31 are mutually the same or different,

[0078] a plurality of R.sub.32 are mutually the same or different; and

[0079] * is a bonding portion to another atom or another structure in the molecule of the compound M3.

[0080] In the formula (32), when X.sub.30 is “a nitrogen atom bonded to another atom or another structure in the molecule of the compound M3”, the formula (32) is represented by a formula (32-1) below.

[0081] In the formula (32), when X.sub.30 is “a carbon atom bonded to R.sub.38 and another atom or another structure in the molecule of the compound M3”, the formula (32) is represented by a formula (32-2) below.

[0082] In the formula (32), when X.sub.30 is “a silicon atom bonded to R.sub.39 and another atom or another structure in the molecule of the compound M3, the formula (32) is represented by a formula (32-3) below.

[0083] In the formulae (32-1) to (32-3), A.sub.41 to A.sub.44 each independently represent the same as A.sub.41 to A.sub.44 in the formula (32), R.sub.38 and R.sub.39 each independently represent the same as R.sub.32 in the formula (32), and * is a bonding portion to another atom or another structure in the molecule of the compound M3.

##STR00004##

[0084] In the exemplary embodiment, the partial structure represented by the formula (31) is preferably represented by any of groups represented by formulae (31a) to (31f) below, and monovalent or higher-valent residues derived from compounds represented by formulae (31g) to (31k), (31m), (31n), (31p), and (31q) below.

##STR00005## ##STR00006## ##STR00007## ##STR00008## ##STR00009##

[0085] In the formulae (31a) to (31f), Y.sub.12 to Y.sub.16 are each independently a nitrogen atom or CR.sub.31, each R.sub.31 independently represents the same as R.sub.31 in the formula (31), and * is a bonding portion to another atom or another structure in the molecule of the compound M3;

[0086] in the formulae (31g) to (31k), (31m), (31n), and (31p), Y.sub.11 to Y.sub.14, Y.sub.17 to Y.sub.39, and Y.sub.70 to Y.sub.95 are each independently a nitrogen atom or CR.sub.31, or a carbon atom bonded to another atom or another structure in the molecule of the compound M3, each R.sub.31 independently represents the same as R.sub.31 in the formula (31), and at least one of Y.sub.11 to Y.sub.14, Y.sub.17 to Y.sub.39, or Y.sub.70 to Y.sub.95 is a carbon atom bonded to another atom or another structure in the molecule of the compound M3;

[0087] in the formula (31 q), Y.sub.11 to Y.sub.14 and Y.sub.21 to Y.sub.24 are each independently a nitrogen atom or CR.sub.31, or a carbon atom bonded to another atom or another structure in the molecule of the compound M3, each R.sub.31 independently represents the same as R.sub.31 in the formula (31), X.sub.32 and X.sub.33 each independently represent the same as X.sub.30 in the formula (32), and at least one of carbon atoms in Y.sub.11 to Y.sub.14, carbon atoms in Y.sub.21 to Y.sub.24, nitrogen atoms in X.sub.32 and X.sub.33, carbon atoms in X.sub.32 and X.sub.33, or silicon atoms in X.sub.32 and X.sub.33 is bonded to another atom or another structure in the molecule of the compound M3, and

[0088] * is a bonding portion to another atom or another structure in the molecule of the compound M3.

[0089] In the formulae (31a) to (31k), (31m), (31n), (31p), and (31q), at least one of R.sub.31 in CR.sub.31 is preferably a deuterium atom.

[0090] In the exemplary embodiment, the partial structure represented by the formula (32) is preferably represented by any of groups represented by formulae (32a) to (32f) below, and monovalent or higher-valent residues derived from compounds represented by formulae (32g) to (32k), (32m), (32n), and (32p) below.

##STR00010##

[0091] In the formulae (32a) to (32f), Y.sub.410 to Y.sub.413 are each independently a nitrogen atom or CR.sub.32, each R.sub.32 independently represents the same as R.sub.32 in the formula (32), X.sub.30 represents the same as X.sub.30 in the formula (32), and * is a bonding portion to another atom or another structure in the molecule of the compound M3;

[0092] in the formula (32g), Y.sub.410 to Y.sub.411 and Y.sub.45 to Y.sub.48 are each independently a nitrogen atom or CR.sub.32, or a carbon atom bonded to another atom or another structure in the molecule of the compound M3, each R.sub.32 independently represents the same as R.sub.32 in the formula (32), X.sub.30 represents the same as X.sub.30 in the formula (32), at least one of carbon atoms in Y.sub.410 to Y.sub.411 and Y.sub.45 to Y.sub.48, a nitrogen atom in X.sub.30, a carbon atom in X.sub.30, or a silicon atom in X.sub.30 is bonded to another atom or another structure in the molecule of the compound M3;

[0093] in the formula (32h), Y.sub.41 to Y.sub.48 are each independently a nitrogen atom or CR.sub.32, or a carbon atom bonded to another atom or another structure in the molecule of the compound M3, each R.sub.32 independently represents the same as R.sub.32 in the formula (32), X.sub.30 represents the same as X.sub.30 in the formula (32), at least one of carbon atoms in Y.sub.41 to Y.sub.48, a nitrogen atom in X.sub.30, a carbon atom in X.sub.30, or a silicon atom in X.sub.30 is bonded to another atom or another structure in the molecule of the compound M3; and

[0094] * is a bonding portion to another atom or another structure in the molecule of the compound M3.

[0095] It should be noted that when X.sub.30 in the formula (32h) is an oxygen atom or a sulfur atom, Y.sub.41 to Y.sub.48 are each preferably CR.sub.32. That is, it is preferable that the partial structure represented by the formula (32h) is not an aza-dibenzofuran ring or an aza-dibenzothiophene ring.

##STR00011## ##STR00012## ##STR00013## ##STR00014## ##STR00015## ##STR00016##

[0096] In the formulae (32i) to (32k), (32m), (32n), and (32p), Y.sub.41 to Y.sub.48 and Y.sub.61 to Y.sub.64 are each independently a nitrogen atom or CR.sub.32, or a carbon atom bonded to another atom or another structure in the molecule of the compound M3, each R.sub.32 independently represents the same as R.sub.32 in the formula (32), X.sub.30 and X.sub.31 each independently represent the same as X.sub.30 in the formula (32), and

[0097] at least one of carbon atoms in Y.sub.41 to Y.sub.48 and Y.sub.61 to Y.sub.64, nitrogen atoms in X.sub.30 and X.sub.31, carbon atoms in X.sub.30 and X.sub.31, or silicon atoms in X.sub.30 and X.sub.31 is bonded to another atom or another structure in the molecule of the compound M3.

[0098] In the formulae (32a) to (32k), (32m), (32n), and (32p), at least one of R.sub.32 in CR.sub.32 is preferably a deuterium atom.

[0099] In the formulae (32a) to (32k), (32m), (32n), and (32p), when at least one of R.sub.32 in CR.sub.32 is a substituent and the substituent has one or more hydrogen atoms, it is preferable that at least one of the hydrogen atoms is a deuterium atom or all the hydrogen atoms are deuterium atoms.

[0100] In the compound M3 of the exemplary embodiment, R.sub.31, R.sub.32, and R.sub.331 to R.sub.333 are preferably each independently a hydrogen atom, a halogen atom, a cyano group, an unsubstituted aryl group having 6 to 30 ring carbon atoms, an unsubstituted heterocyclic group having 5 to 30 ring atoms, an unsubstituted alkyl group having 1 to 30 carbon atoms, an unsubstituted alkyl halide group having 1 to 30 carbon atoms, an unsubstituted alkylsilyl group having 3 to 30 carbon atoms, an unsubstituted arylsilyl group having 6 to 60 ring carbon atoms, an unsubstituted arylphosphoryl group having 6 to 60 ring carbon atoms, an unsubstituted alkoxy group having 1 to 30 carbon atoms, an unsubstituted aryloxy group having 6 to 30 ring carbon atoms, an amino group, an unsubstituted alkylamino group having 2 to 30 carbon atoms, an unsubstituted arylamino group having 6 to 60 ring carbon atoms, a thiol group, an unsubstituted alkylthio group having 1 to 30 carbon atoms, or an unsubstituted arylthio group having 6 to 30 ring carbon atoms,

[0101] more preferably, a hydrogen atom, a halogen atom, a cyano group, an unsubstituted aryl group having 6 to 14 ring carbon atoms, an unsubstituted heterocyclic group having 5 to 14 ring atoms, an unsubstituted alkyl group having 1 to 6 carbon atoms, an unsubstituted alkyl halide group having 1 to 6 carbon atoms, an unsubstituted alkylsilyl group having 3 to 6 carbon atoms, an unsubstituted arylsilyl group having 6 to 60 ring carbon atoms, an unsubstituted arylphosphoryl group having 6 to 60 ring carbon atoms, an unsubstituted alkoxy group having 1 to 6 carbon atoms, an unsubstituted aryloxy group having 6 to 14 ring carbon atoms, an amino group, an unsubstituted alkylamino group having 2 to 12 carbon atoms, an unsubstituted arylamino group having 6 to 60 ring carbon atoms, a thiol group, an unsubstituted alkylthio group having 1 to 6 carbon atoms, or an unsubstituted arylthio group having 6 to 14 ring carbon atoms, and

[0102] further preferably a hydrogen atom.

[0103] In the compound M3 of the exemplary embodiment, R.sub.33 to R.sub.39 in X.sub.30 and R.sub.33 to R.sub.39 in X.sub.31 (which represent the same as R.sub.33 to R.sub.39 in X.sub.30) are preferably each independently a hydrogen atom, an unsubstituted aryl group having 6 to 30 ring carbon atoms, an unsubstituted heterocyclic group having 5 to 30 ring atoms, an unsubstituted alkyl group having 1 to 30 carbon atoms, or an unsubstituted alkyl halide group having 1 to 30 carbon atoms,

[0104] more preferably, a hydrogen atom, an unsubstituted aryl group having 6 to 14 ring carbon atoms, an unsubstituted heterocyclic group having 5 to 14 ring atoms, an unsubstituted alkyl group having 1 to 6 carbon atoms, or an unsubstituted alkyl halide group having 1 to 6 carbon atoms, and

[0105] further preferably, an unsubstituted aryl group having 6 to 14 ring carbon atoms, or an unsubstituted alkyl group having 1 to 6 carbon atoms.

[0106] In the compound M3 of the exemplary embodiment, when any one or more of R.sub.31, R.sub.32, R.sub.331 to R.sub.333, R.sub.33 to R.sub.39 in X.sub.30, and R.sub.33 to R.sub.39 in X.sub.31 (which represent the same as R.sub.33 to R.sub.39 in X.sub.30) are hydrogen atoms, it is preferable that all the hydrogen atoms are protium atoms, at least one of the hydrogen atoms is a deuterium atom, or all the hydrogen atoms are deuterium.

[0107] In the compound M3 of the exemplary embodiment, when any one or more of R.sub.31, R.sub.32, R.sub.331 to R.sub.333, R.sub.33 to R.sub.39 in X.sub.30, and R.sub.33 to R.sub.39 in X.sub.31 (which represent the same as R.sub.33 to R.sub.39 in X.sub.30) are substituents and the substituents have one or more hydrogen atoms, it is preferable that all the hydrogen atoms are protium atoms, at least one of the hydrogen atoms is a deuterium atom, or all the hydrogen atoms are deuterium atoms.

[0108] Examples of partial structures represented by any of the formulae (31) to (48) include partial structures represented by formulae (3-1A) to (3-25A) and (3-1B) to (3-25B) below.

[0109] It is also preferable that the compound M3 includes, in one molecule thereof, at least any of partial structures represented by formulae (3-1A) to (3-25A) and (3-1B) to (3-25B) below.

##STR00017##

[0110] In the formulae (3-1A) to (3-7A), R.sub.301 to R.sub.306 each independently represent the same as R.sub.31 in the formula (31), and at least one of R.sub.301 to R.sub.306 is a single bond bonded to another atom or another structure in the molecule of the compound M3.

[0111] In the formulae (3-1A) to (3-7A), at least one pair of the following are mutually bonded to form a ring or not bonded to form no ring: a pair of adjacent R.sub.301 and R.sub.302, a pair of adjacent R.sub.302 and R.sub.303, a pair of adjacent R.sub.303 and R.sub.304, a pair of adjacent R.sub.304 and R.sub.305, a pair of adjacent R.sub.305 and R.sub.306, or a pair of adjacent R.sub.306 and R.sub.301.

##STR00018##

[0112] In the formulae (3-8A) to (3-13A), R.sub.300 each independently represent the same as R.sub.31 in the formula (31), at least one of R.sub.300 is a single bond bonded to another atom or another structure in the molecule of the compound M3, and a plurality of R.sub.300 are mutually the same or different.

[0113] In the formulae (3-8A) to (3-13A), at least one pair of pairs of adjacent ones of R.sub.300 are mutually bonded to form a ring or not bonded to form no ring.

##STR00019##

[0114] In the formulae (3-14A) to (3-18A), R.sub.300 and R.sub.312 to R.sub.314 each independently represent the same as R.sub.31 in the formula (31), each X.sub.300 independently represents the same as X.sub.30 in the formula (32), at least one of R.sub.300 or R.sub.312 to R.sub.314 is a single bond bonded to another atom or another structure in the molecule of the compound M3, or at least one of a nitrogen atom, a carbon atom, or a silicon atom in X.sub.300 is bonded to another atom or another structure in the molecule of the compound M3, and a plurality of R.sub.300 are mutually the same or different.

[0115] In the formulae (3-14A) to (3-18A), at least one pair of the following are mutually bonded to form a ring or not bonded to form no ring: pairs of adjacent ones of R.sub.300, a pair of R.sub.312 and R.sub.313, a pair of R.sub.34 and R.sub.35 in X.sub.300 (which represent the same as a pair of R.sub.34 and R.sub.35 in X.sub.30), or a pair of R.sub.36 and R.sub.37 in X.sub.300 (which represent the same as a pair of R.sub.36 and R.sub.37 in X.sub.30).

##STR00020##

[0116] In the formulae (3-19A) to (3-23A), R.sub.300 and R.sub.312 to R.sub.314 each independently represent the same as R.sub.31 in the formula (31), at least one of R.sub.300 or R.sub.312 to R.sub.314 is a single bond bonded to another atom or another structure in the molecule of the compound M3, and a plurality of R.sub.300 are mutually the same or different.

[0117] In the formulae (3-19A) to (3-23A), at least one pair of the following are mutually bonded to form a ring or not bonded to form no ring: pairs of adjacent ones of R.sub.300 or a pair of R.sub.312 and R.sub.313.

##STR00021##

[0118] In the formulae (3-24A) and (3-25A), R.sub.300 each independently represent the same as R.sub.31 in the formula (31), at least one of R.sub.300 is a single bond bonded to another atom or another structure in the molecule of the compound M3, and a plurality of R.sub.300 are mutually the same or different.

[0119] In the formulae (3-24A) and (3-25A), at least one pair of pairs of adjacent ones of R.sub.300 are mutually bonded to form a ring or not bonded to form no ring.

##STR00022## ##STR00023##

[0120] In the formulae (3-1B) to (3-9B), R.sub.314 and R.sub.401 to R.sub.411 each independently represent the same as R.sub.32 in the formula (32), and at least one of R.sub.314 or R.sub.401 to R.sub.411 is a single bond bonded to another atom or another structure in the molecule of the compound M3.

[0121] In the formulae (3-1B) and (3-2B), at least one pair of the following are mutually bonded to form a ring or not bonded to form no ring: a pair of R.sub.402 and R.sub.403, a pair of R.sub.403 and R.sub.314, or a pair of R.sub.314 and R.sub.401.

[0122] In the formulae (3-5B) and (3-6B), at least one pair of the following are mutually bonded to form a ring or not bonded to form no ring: a pair of R.sub.404 and R.sub.405, a pair of R.sub.405 and R.sub.406, a pair of R.sub.406 and R.sub.407, a pair of R.sub.407 and R.sub.408, or a pair of R.sub.408 and R.sub.409.

[0123] In the formula (3-7B), at least one pair of the following are mutually bonded to form a ring or not bonded to form no ring: a pair of R.sub.404 and R.sub.405, a pair of R.sub.405 and R.sub.406, a pair of R.sub.406 and R.sub.407, a pair of R.sub.407 and R.sub.408, a pair of R.sub.408 and R.sub.409, a pair of R.sub.409 and R.sub.314, or a pair of R.sub.314 and R.sub.404.

[0124] In the formulae (3-8B) and (3-9B), at least one pair of the following are mutually bonded to form a ring or not bonded to form no ring: a pair of R.sub.404 and R.sub.405, a pair of R.sub.405 and R.sub.406, a pair of R.sub.410 and R.sub.411, or a pair of R.sub.411 and R.sub.409.

##STR00024## ##STR00025##

[0125] In the formulae (3-10B) to (3-17B), R.sub.300 and R.sub.312 to R.sub.315 each independently represent the same as R.sub.32 in the formula (32), at least one of R.sub.300 or R.sub.312 to R.sub.315 is a single bond bonded to another atom or another structure in the molecule of the compound M3, and a plurality of R.sub.300 are mutually the same or different.

[0126] In the formulae (3-10B) to (3-17B), at least one pair of the following are mutually bonded to form a ring or not bonded to form no ring: pairs of adjacent ones of R.sub.300 or a pair of R.sub.312 and R.sub.313.

##STR00026##

[0127] In the formulae (3-18B) to (3-23B), R.sub.300 each independently represent the same as R.sub.32 in the formula (32), X.sub.30 and X.sub.31 each independently represent the same as X.sub.30 in the formula (32), at least one of R.sub.300 is a single bond bonded to another atom or another structure in the molecule of the compound M3, or at least one of a nitrogen atom, a carbon atom, or a silicon atom in X.sub.30 to X.sub.31 is bonded to another atom or another structure in the molecule of the compound M3, and a plurality of R.sub.300 are mutually the same or different.

[0128] In the formulae (3-18B) to (3-23B), at least one pair of the following are mutually bonded to form a ring or not bonded to form no ring: pairs of adjacent ones of R.sub.300, a pair of R.sub.34 and R.sub.35 in X.sub.30, a pair of R.sub.36 and R.sub.37 in X.sub.30, a pair of R.sub.34 and R.sub.35 in X.sub.31 (which represent the same as a pair of R.sub.34 and R.sub.35 in X.sub.30), or a pair of R.sub.36 and R.sub.37 in X.sub.31 (which represent the same as a pair of R.sub.36 and R.sub.37 in X.sub.30).

##STR00027##

[0129] In the formulae (3-24B) and (3-25B), R.sub.300 each independently represent the same as R.sub.32 in the formula (32), X.sub.31 to X.sub.33 each independently represent the same as X.sub.30 in the formula (32), at least one of R.sub.300 is a single bond bonded to another atom or another structure in the molecule of the compound M3, or at least one of a nitrogen atom, a carbon atom, or a silicon atom in X.sub.31 to X.sub.33 is bonded to another atom or another structure in the molecule of the compound M3, and a plurality of R.sub.300 are mutually the same or different.

[0130] In the formulae (3-24B) and (3-25B), at least one pair of the following are mutually bonded to form a ring or not bonded to form no ring: pairs of adjacent ones of R.sub.300, a pair of R.sub.34 and R.sub.35 in X.sub.31 to X.sub.33 (which represent the same as a pair of R.sub.34 and R.sub.35 in X.sub.30), or a pair of R.sub.36 and R.sub.37 in X.sub.31 to X.sub.33 (which represent the same as a pair of R.sub.34 and R.sub.35 in X.sub.30).

[0131] In the formulae (3-1A) to (3-25A) and (3-1B) to (3-25B), R.sub.300, R.sub.301 to R.sub.306, R.sub.312 to R.sub.315, and R.sub.401 to R.sub.411 are preferably each independently a hydrogen atom, an unsubstituted aryl group having 6 to 30 ring carbon atoms, an unsubstituted heterocyclic group having 5 to 30 ring atoms, an unsubstituted alkyl group having 1 to 30 carbon atoms, or an unsubstituted alkyl halide group having 1 to 30 carbon atoms,

[0132] more preferably, a hydrogen atom, an unsubstituted aryl group having 6 to 14 ring carbon atoms, an unsubstituted heterocyclic group having 5 to 14 ring atoms, an unsubstituted alkyl group having 1 to 6 carbon atoms, or an unsubstituted alkyl halide group having 1 to 6 carbon atoms, and

[0133] further preferably, an unsubstituted aryl group having 6 to 14 ring carbon atoms, or an unsubstituted alkyl group having 1 to 6 carbon atoms.

[0134] In the formulae (3-1A) to (3-25A) and (3-1B) to (3-25B), R.sub.33 to R.sub.39 in X.sub.31 to X.sub.33 and X.sub.300 (which represent the same as R.sub.33 to R.sub.39 in X.sub.30) are preferably each independently a hydrogen atom, an unsubstituted aryl group having 6 to 30 ring carbon atoms, an unsubstituted heterocyclic group having 5 to 30 ring atoms, an unsubstituted alkyl group having 1 to 30 carbon atoms, or an unsubstituted alkyl halide group having 1 to 30 carbon atoms,

[0135] more preferably, a hydrogen atom, an unsubstituted aryl group having 6 to 14 ring carbon atoms, an unsubstituted heterocyclic group having 5 to 14 ring atoms, an unsubstituted alkyl group having 1 to 6 carbon atoms, or an unsubstituted alkyl halide group having 1 to 6 carbon atoms, and

[0136] further preferably, an unsubstituted aryl group having 6 to 14 ring carbon atoms, or an unsubstituted alkyl group having 1 to 6 carbon atoms.

[0137] In the formulae (3-1A) to (3-25A) and (3-1B) to (3-25B), when any one or more of R.sub.300, R.sub.301 to R.sub.306, R.sub.312 to R.sub.315, R.sub.401 to R.sub.411, and R.sub.33 to R.sub.39 in X.sub.31 to X.sub.33 and X.sub.300 (which represent the same as R.sub.33 to R.sub.39 in X.sub.30) are hydrogen atoms, it is preferable that all the hydrogen atoms are protium atoms, at least one of the hydrogen atoms is a deuterium atom, or all the hydrogen atoms are deuterium.

[0138] In the formulae (3-1A) to (3-25A) and (3-1B) to (3-25B), when any one or more of R.sub.300, R.sub.301 to R.sub.306, R.sub.312 to R.sub.315, R.sub.401 to R.sub.411, and R.sub.33 to R.sub.39 in X.sub.31 to X.sub.33 and X.sub.300 (which represent the same as R.sub.33 to R.sub.39 in X.sub.30) are substituents and the substituents have one or more hydrogen atoms, it is preferable that all the hydrogen atoms are protium atoms, at least one of the hydrogen atoms is a deuterium atom, or all the hydrogen atoms are deuterium atoms.

[0139] In the exemplary embodiment, the compound M3 preferably has at least one group of a cyano group, an amino group, a substituted or unsubstituted alkylamino group having 2 to 30 carbon atoms, or a substituted or unsubstituted arylamino group having 6 to 60 ring carbon atoms,

[0140] or preferably has at least one monovalent or higher-valent residue derived from any of a substituted or unsubstituted benzene, a substituted or unsubstituted naphthalene, a substituted or unsubstituted indole, a substituted or unsubstituted carbazole, a substituted or unsubstituted dibenzofuran, a substituted or unsubstituted dibenzothiophene, a substituted or unsubstituted fluorene, a compound represented by a formula (36a) below, a substituted or unsubstituted triazine, a substituted or unsubstituted pyrimidine, a substituted or unsubstituted pyridine, a substituted or unsubstituted pyridazine, a substituted or unsubstituted pyrazine, a substituted or unsubstituted imidazole, a substituted or unsubstituted benzimidazole, a substituted or unsubstituted phenanthrene, a substituted or unsubstituted anthracene, a substituted or unsubstituted triphenylene, a substituted or unsubstituted chrysene, a substituted or unsubstituted fluoranthene, and a substituted or unsubstituted benzochrysene.

##STR00028##

[0141] In the formula (36a), R.sub.36 to R.sub.38 are each independently a hydrogen atom or a substituent, or at least one pair of pairs of adjacent ones of R.sub.38 or a pair of R.sub.36 and R.sub.37 are mutually bonded to form a ring, R.sub.36 to R.sub.38 serving as the substituents are each independently a halogen atom, a cyano group, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 30 carbon atoms, a substituted or unsubstituted arylsilyl group having 6 to 60 ring carbon atoms, a substituted or unsubstituted arylphosphoryl group having 6 to 60 ring carbon atoms, a hydroxy group, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms, an amino group, a substituted or unsubstituted alkylamino group having 2 to 30 carbon atoms, a substituted or unsubstituted arylamino group having 6 to 60 ring carbon atoms, a thiol group, a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted germanium group, a substituted phosphine oxide group, a nitro group or a substituted or unsubstituted carbonyl group, and

[0142] a plurality of R.sub.38 are mutually the same or different.

[0143] In the exemplary embodiment, the compound M3 more preferably has a cyano group, or more preferably has at least one monovalent or higher-valent residue derived from any of a substituted or unsubstituted carbazole, a substituted or unsubstituted dibenzofuran, a substituted or unsubstituted dibenzothiophene, a substituted or unsubstituted fluorene, a compound represented by the formula (36a), a substituted or unsubstituted triazine, a substituted or unsubstituted pyrimidine, a substituted or unsubstituted pyridine, and a substituted or unsubstituted triphenylene.

[0144] In the exemplary embodiment, the compound M3 further preferably has a cyano group, or further preferably has at least one monovalent or higher-valent residue derived from any of a substituted or unsubstituted carbazole, a substituted or unsubstituted dibenzofuran, a substituted or unsubstituted dibenzothiophene, a substituted or unsubstituted triazine, and a substituted or unsubstituted pyrimidine.

[0145] In the exemplary embodiment, the compound M3 further preferably has a monovalent or higher-valent residue derived from a substituted or unsubstituted carbazole.

[0146] In the exemplary embodiment, the compound M3 further preferably has a monovalent or higher-valent residue derived from a structure represented by a formula (3-10) below.

##STR00029##

[0147] In the formula (3-10), H.sub.D1 to HDS are hydrogen atoms, at least one of H.sub.D1 to HDS is a deuterium atom, R.sub.311 is a substituent, and at least one of D.sub.1 to D.sub.8 or R.sub.311 is a single bond bonded to another atom or another structure in the molecule of the compound M3, and

[0148] R.sub.311 serving as the substituent is a halogen atom, a cyano group, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 30 carbon atoms, a substituted or unsubstituted arylsilyl group having 6 to 60 ring carbon atoms, a substituted or unsubstituted arylphosphoryl group having 6 to 60 ring carbon atoms, a hydroxy group, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms, an amino group, a substituted or unsubstituted alkylamino group having 2 to 30 carbon atoms, a substituted or unsubstituted arylamino group having 6 to 60 ring carbon atoms, a thiol group, a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted germanium group, a substituted phosphine oxide group, a nitro group, a substituted or unsubstituted carbonyl group, or a substituted boryl group.

[0149] In the exemplary embodiment, the compound M3 further preferably has a monovalent or higher-valent residue derived from a structure represented by a formula (3-100) below.

##STR00030##

[0150] In the formula (3-100), D.sub.1 to D.sub.8 are each a deuterium atom, R.sub.310 is a substituent, and at least one of D.sub.1 to D.sub.8 or R.sub.310 is a single bond bonded to another atom or another structure in the molecule of the compound M3, and

[0151] R.sub.310 serving as the substituent represents the same as R.sub.311 in the formula (3-10).

[0152] In the formulae (3-10) and (3-100), R.sub.310 and R.sub.311 are preferably each independently a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, or a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms,

[0153] more preferably, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms,

[0154] and further preferably, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms.

Compound M3 Represented by Formula (301) or (302) Below

[0155] In the exemplary embodiment, the compound M3 is also preferably a compound represented by a formula (301) or (302) below.

##STR00031##

[0156] In the formula (301), Ar.sub.301 is a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycle having 5 to 30 ring atoms;

[0157] m1 is 1, 2, 3, 4, 5, or 6;

[0158] each R.sub.301 is an electron-donating group, and each R.sub.301 is bonded to an element forming Ar.sub.301;

[0159] when m1 is 2 or more, a plurality of R.sub.301 are mutually the same or different; and

[0160] Ar.sub.301 is not an electron-accepting aromatic hydrocarbon ring or heterocycle, and when Ar.sub.301 has a substituent, the substituent is not an electron-accepting group; and

[0161] in the formula (302), Ar.sub.302 is a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocycle having 5 to 30 ring atoms;

[0162] n1 is 1, 2, 3, 4, 5, or 6;

[0163] each R.sub.302 is an electron-accepting group, and each R.sub.302 is bonded to an element forming Ar.sub.302;

[0164] when n1 is 2 or more, a plurality of R.sub.302 are mutually the same or different; and

[0165] Ar.sub.302 is not an electron-donating aromatic hydrocarbon ring or heterocycle, and when Ar.sub.302 has a substituent, the substituent is not an electron-donating group.

[0166] In the formulae (301) and (302), Ar.sub.301 and Ar.sub.302 are preferably each independently a monovalent or higher-valent residue derived from any of compounds represented by formulae (A1) to (A3) below.

##STR00032##

[0167] In the formulae (A1) to (A3), X.sub.A is an oxygen atom or a sulfur atom, and R.sub.A is a hydrogen atom or a substituent.

[0168] In the formula (A3), when R.sub.A is a substituent, the substituent may be, for instance, the same group as R.sub.31 in the formula (31).

[0169] In the formula (301), each R.sub.301 serving as the electron-donating group is preferably independently a monovalent or higher-valent residue derived from any of compounds represented by formulae (D1) to (D6) and (D8) to (D10) below, or a group represented by a formula (D7) below, and in the formula (302), each R.sub.302 serving as the electron-accepting group is preferably independently a monovalent or higher-valent residue derived from any of compounds represented by formulae (A4) to (A18) and (A22) and (A23) below, or any of groups represented by formulae (A1) to (A3), (A19) to (A21), and (A24) below.

##STR00033##

[0170] In the formula (D7), each * represents a bonding portion to an element forming Ar.sub.301.

##STR00034## ##STR00035##

[0171] In the formula (A1), n.sub.A is 1, 2, or 3;

[0172] in the formulae (A22) and (A23), X.sub.1 to X.sub.8 are each independently CR.sub.320 or a carbon atom bonded to another atom or another structure in the molecule of the compound M3, each R.sub.320 is independently a hydrogen atom or a substituent, or at least one pair of pairs of adjacent ones of R.sub.320 are mutually bonded to form a ring, and at least one of carbon atoms in X.sub.1 to X.sub.8 is bonded to an element forming Ar.sub.302;

[0173] in the formula (A24), X.sub.1 to X.sub.8 are each independently a nitrogen atom or CR.sub.320, or a carbon atom bonded to an element forming Ar.sub.302, and each R.sub.320 is independently a hydrogen atom or a substituent, or at least one pair of pairs of adjacent ones of R.sub.320 are mutually bonded to form a ring; and

[0174] in the formulae (A1) to (A3), (A19) to (A21), and (A24), each * represents a bonding portion to an element forming Ar.sub.302.

[0175] R.sub.320 in the formulae (A1) to (A3) represents the same as R.sub.31 in the formula (31).

Manufacturing Method of Compound M3 (Deuterated Compound M3) According to Exemplary Embodiment

[0176] The compound M3 can be manufactured by a publicly known method.

[0177] The compound M3 can be manufactured by, for instance, the following method.

[0178] A compound (non-deuterated compound m3) in which all hydrogen atoms in the compound M3 are protium atoms is first prepared by well-known coupling and substitution reactions. Subsequently, a deuterated precursor substance is used, or more generally, the non-deuterated compound m3 is treated with a deuterated solvent (such as d6-benzene) in the presence of a Lewis acid H/D exchange catalyst (such as aluminum trichloride or ethyl aluminum chloride).

[0179] The compound M3 can also be manufactured in accordance with the reactions described in Examples below using known alternative reactions and raw materials according to the target compound.

Specific Examples of Compound M3

[0180] Specific examples of the compound M3 of the exemplary embodiment include compounds below. It should however be noted that the invention is not limited to the specific examples of the compound.

[0181] In some of the specific examples of the compound M3, hydrogen atoms are omitted.

[0182] Specific examples of the compound M3 in which hydrogen atoms are omitted will be described.

[0183] For instance, in the case where a specific example of the compound M3 is a compound represented by (M3-1) below, the compound is represented by a formula (M3-11) below when shown without omitting hydrogen atoms.

[0184] In the formula (M3-11) below, “H.sub.D” each represent a protium atom or a deuterium atom, and at least one of the plurality of “H.sub.D” is a deuterium atom.

##STR00036##

[0185] Similarly, for instance, in the case where a specific example of the compound M3 is a compound represented by (M3-2) below, the compound is represented by a formula (M3-21) below when shown without omitting hydrogen atoms.

[0186] In the formula (M3-21) below, “H.sub.D” each represent a protium atom or a deuterium atom, and at least one of the plurality of “H.sub.D” is a deuterium atom.

##STR00037##

[0187] The following specific examples of the compound M3 are specific examples in which hydrogen atoms are omitted.

##STR00038## ##STR00039## ##STR00040## ##STR00041## ##STR00042## ##STR00043## ##STR00044## ##STR00045## ##STR00046## ##STR00047## ##STR00048## ##STR00049##

##STR00050## ##STR00051## ##STR00052## ##STR00053## ##STR00054## ##STR00055## ##STR00056## ##STR00057## ##STR00058## ##STR00059## ##STR00060## ##STR00061## ##STR00062## ##STR00063## ##STR00064## ##STR00065## ##STR00066## ##STR00067## ##STR00068## ##STR00069## ##STR00070## ##STR00071## ##STR00072##

[0188] The following specific examples of the compound M3 are specific examples in which hydrogen atoms are not omitted.

##STR00073## ##STR00074## ##STR00075## ##STR00076## ##STR00077## ##STR00078## ##STR00079## ##STR00080## ##STR00081## ##STR00082## ##STR00083## ##STR00084## ##STR00085## ##STR00086## ##STR00087## ##STR00088## ##STR00089## ##STR00090## ##STR00091## ##STR00092## ##STR00093## ##STR00094## ##STR00095## ##STR00096## ##STR00097## ##STR00098## ##STR00099##

Compound M2

[0189] The compound M2 of the exemplary embodiment is a delayed fluorescent compound having at least one deuterium atom. The delayed fluorescent compound is not particularly limited.

[0190] Herein, a “compound M2 having at least one deuterium atom” refers to a compound in which the hydrogen atoms in the compound M2 are not composed only of protium atoms.

[0191] In the following description, a “compound M2 having at least one deuterium atom” may be referred to as a “deuterated compound M2”. A compound in which all hydrogen atoms in the compound M2 are protium atoms may be referred to as a “non-deuterated compound m2”.

[0192] In the exemplary embodiment, a content ratio of the non-deuterated compound m2 relative to the total of the deuterated compound M2 and the non-deuterated compound m2 in the emitting layer is 99% by mole or less. The content ratio of the non-deuterated compound m2 can be examined by mass spectrometry.

[0193] In the exemplary embodiment, a content ratio of the deuterated compound M2 relative to the total of the deuterated compound M2 and the non-deuterated compound m2 in the emitting layer is preferably 30% by mole or more, 50% by mole or more, 70% by mole or more, 90% by mole or more, 95% by mole or more, 99% by mole or more, or 100% by mole.

[0194] In the exemplary embodiment, it is also preferable that deuterium atoms account for 10% or more of the total number of hydrogen atoms in the compound M2, deuterium atoms account for 20% or more thereof, deuterium atoms account for 30% or more thereof, deuterium atoms account for 40% or more thereof, deuterium atoms account for 50% or more thereof, deuterium atoms account for 60% or more thereof, deuterium atoms account for 70% or more thereof, and deuterium atoms account for 80% or more thereof.

[0195] Whether a deuterium atom is included in the compound M2 is checked by the same method as the “Method for Checking Whether Deuterium Atom Is Included in Compound M3” described above.

[0196] The bonding position of a deuterium atom in the compound M2 is specified by the same method as the “Method for Specifying Bonding Position of Deuterium Atom in Compound M3” described above.

Delayed Fluorescence

[0197] Delayed fluorescence is explained in “Yuki Hando-tai no Debaisu Bussei (Device Physics of Organic Semiconductors)” (edited by ADACHI, Chihaya, published by Kodansha, on pages 261-268). This document describes that, if an energy gap ΔE.sub.13 of a fluorescent material between a singlet state and a triplet state is reducible, a reverse energy transfer from the triplet state to the singlet state, which usually occurs at a low transition probability, would occur at a high efficiency to express thermally activated delayed fluorescence (TADF). Further, a mechanism of generating delayed fluorescence is explained in FIG. 10.38 in the document. The compound M2 of the exemplary embodiment is preferably a compound exhibiting thermally activated delayed fluorescence generated by such a mechanism.

[0198] In general, emission of delayed fluorescence can be determined by measuring the transient PL (Photo Luminescence).

[0199] The behavior of delayed fluorescence can also be analyzed based on the decay curve obtained from the transient PL measurement. The transient PL measurement is a method of irradiating a sample with a pulse laser to excite the sample, and measuring the decay behavior (transient characteristics) of PL emission after the irradiation is stopped. PL emission in TADF materials is classified into a light emission component from a singlet exciton generated by the first PL excitation and a light emission component from a singlet exciton generated via a triplet exciton. The lifetime of the singlet exciton generated by the first PL excitation is on the order of nanoseconds and is very short. Therefore, light emission from the singlet exciton rapidly attenuates after irradiation with the pulse laser.

[0200] On the other hand, the delayed fluorescence is gradually attenuated due to light emission from a singlet exciton generated via a triplet exciton having a long lifetime. As described above, there is a large temporal difference between the light emission from the singlet exciton generated by the first PL excitation and the light emission from the singlet exciton generated via the triplet exciton. Therefore, the luminous intensity derived from delayed fluorescence can be determined.

[0201] FIG. 2 shows a schematic diagram of an exemplary device for measuring the transient PL. An example of a method of measuring a transient PL using FIG. 2 and an example of behavior analysis of delayed fluorescence will be described.

[0202] A transient PL measuring device 100 in FIG. 2 includes: a pulse laser 101 capable of radiating a light having a predetermined wavelength; a sample chamber 102 configured to house a measurement sample; a spectrometer 103 configured to divide a light radiated from the measurement sample; a streak camera 104 configured to provide a two-dimensional image; and a personal computer 105 configured to import and analyze the two-dimensional image. A device for measuring the transient PL is not limited to the device described in the exemplary embodiment.

[0203] The sample to be housed in the sample chamber 102 is obtained by doping a matrix material with a doping material at a concentration of 12 mass % and forming a thin film on a quartz substrate.

[0204] The thus-obtained thin film sample is housed in the sample chamber 102, and is irradiated with a pulse laser emitted from the pulse laser 101 to excite the doping material. Emission is extracted in a direction of 90 degrees with respect to a radiation direction of the excited light. The extracted emission is divided by the spectrometer 103 to form a two-dimensional image in the streak camera 104. As a result, the two-dimensional image is obtainable in which the ordinate axis represents a time, the abscissa axis represents a wavelength, and a bright spot represents a luminous intensity. When this two-dimensional image is taken out at a predetermined time axis, an emission spectrum in which the ordinate axis represents the luminous intensity and the abscissa axis represents the wavelength is obtainable. Moreover, when this two-dimensional image is taken out at the wavelength axis, a decay curve (transient PL) in which the ordinate axis represents a logarithm of the luminous intensity and the abscissa axis represents the time is obtainable.

[0205] For instance, a thin film sample A was manufactured as described above from a reference compound H1 as the matrix material and a reference compound D1 as the doping material and was measured in terms of the transient PL.

##STR00100##

[0206] The decay curve was analyzed with respect to the above thin film sample A and a thin film sample B. The thin film sample B was manufactured in the same manner as described above from a reference compound H2 as the matrix material and the reference compound D1 as the doping material.

[0207] FIG. 3 shows decay curves obtained from transient PL obtained by measuring the thin film samples A and B.

##STR00101##

(Reference Compound H2)

[0208] As described above, an emission decay curve in which the ordinate axis represents the luminous intensity and the abscissa axis represents the time can be obtained by the transient PL measurement. Based on the emission decay curve, a fluorescence intensity ratio between fluorescence emitted from a singlet state generated by photo-excitation and delayed fluorescence emitted from a singlet state generated by inverse energy transfer via a triplet state can be estimated. In a delayed fluorescent material, a ratio of the intensity of the slowly decaying delayed fluorescence to the intensity of the promptly decaying fluorescence is relatively large.

[0209] Specifically, Prompt emission and Delay emission are present as emission from the delayed fluorescent material. Prompt emission is observed promptly when the excited state is achieved by exciting the compound of the exemplary embodiment with a pulse beam (i.e., a beam emitted from a pulse laser) having a wavelength absorbable by the delayed fluorescent material. Delay emission is observed not promptly when the excited state is achieved but after the excited state is achieved.

[0210] An amount of Prompt emission, an amount of Delay emission and a ratio between the amounts thereof can be obtained according to the method as described in “Nature 492, 234-238, 2012” (Reference Document 1). The amount of Prompt emission and the amount of Delay emission may be calculated using a device different from one described in Reference Document 1 or one shown in FIG. 2.

[0211] Herein, a sample manufactured by a method shown below is used for measuring delayed fluorescence of the compound M2. For instance, the compound M2 is dissolved in toluene to prepare a dilute solution with an absorbance of 0.05 or less at the excitation wavelength to eliminate the contribution of self-absorption. In order to prevent quenching due to oxygen, the sample solution is frozen and degassed and then sealed in a cell with a lid under an argon atmosphere to obtain an oxygen-free sample solution saturated with argon.

[0212] The fluorescence spectrum of the sample solution is measured with a spectrofluorometer FP-8600 (manufactured by JASCO Corporation), and the fluorescence spectrum of a 9,10-diphenylanthracene ethanol solution is measured under the same conditions. Using the fluorescence area intensities of both spectra, the total fluorescence quantum yield is calculated by an equation (1) in Morris et al. J. Phys. Chem. 80 (1976) 969. An amount of Prompt emission, an amount of Delay emission and a ratio between the amounts thereof can be obtained by a similar method as Reference Document 1. The amount of Prompt emission and the amount of Delay emission may be calculated using a device different from one described in Reference Document 1 or one shown in FIG. 2.

[0213] In the exemplary embodiment, provided that an amount of Prompt emission of a measurement target compound (compound M2) is denoted by X.sub.P and the amount of Delay emission is denoted by X.sub.D, a value of X.sub.D/X.sub.P is preferably 0.05 or more.

[0214] The amounts of Prompt emission and Delay emission and a ratio of the amounts thereof in compounds other than the compound M2 herein are measured in the same manner as those of the compound M2.

[0215] The compound M2 is preferably a compound represented by a formula (2) or (22) below.

Compound Represented by Formula (2)

[0216] ##STR00102##

[0217] In the formula (2):

[0218] n is 1, 2, 3 or 4;

[0219] m is 1, 2, 3, or 4;

[0220] q is 0, 1, 2, 3, or 4;

[0221] m+n+q=6 is satisfied;

[0222] CN is a cyano group;

[0223] D.sub.1 is a group represented by a formula (2a), (2b) or (2c) below, and when a plurality of D.sub.1 are present, the plurality of D.sub.1 are mutually the same or different;

[0224] Rx is a hydrogen atom or a substituent, or a pair of adjacent ones of Rx are bonded to each other to form a ring, and when a plurality of Rx are present, the plurality of Rx are mutually the same or different;

[0225] each Rx as the substituent is independently a halogen atom, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted amino group, a substituted or unsubstituted carbonyl group, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms,

[0226] a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 30 carbon atoms, or a substituted or unsubstituted arylsilyl group having 6 to 60 ring carbon atoms; and

[0227] CN, D.sub.1 and Rx are each bonded to a carbon atom of a six-membered ring.

##STR00103##

[0228] In the formula (2a):

[0229] R.sub.1 to R.sub.8 are each independently a hydrogen atom or a substituent, or at least one pair of a pair of R.sub.1 and R.sub.2, a pair of R.sub.2 and R.sub.3, a pair of R.sub.3 and R.sub.4, a pair of R.sub.5 and R.sub.6, a pair of R.sub.6 and R.sub.7, or a pair of R.sub.7 and R.sub.8 are mutually bonded to form a ring;

[0230] R.sub.1 to R.sub.8 as the substituents are each independently a halogen atom, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 30 carbon atoms, a substituted or unsubstituted arylsilyl group having 6 to 60 ring carbon atoms, a hydroxy group, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy halide group having 1 to 30 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms, a substituted or unsubstituted alkylamino group having 2 to 30 carbon atoms, a substituted or unsubstituted arylamino group having 6 to 60 ring carbon atoms, a thiol group, a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, or a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms; and

[0231] * represents a bonding portion to a carbon atom of a benzene ring in the formula (2).

##STR00104##

[0232] In the formula (2b):

[0233] R.sub.21 to R.sub.28 are each independently a hydrogen atom or a substituent, or at least one pair of a pair of R.sub.21 and R.sub.22, a pair of R.sub.22 and R.sub.23, a pair of R.sub.23 and R.sub.24, a pair of R.sub.25 and R.sub.26, a pair of R.sub.26 and R.sub.27, or a pair of R.sub.27 and R.sub.28 are bonded to each other to form a ring;

[0234] R.sub.21 to R.sub.28 serving as the substituents each independently represent the same as R.sub.1 to R.sub.8 in the formula (2a);

[0235] A represents a cyclic structure represented by a formula (211) or (212) below, and the cyclic structure A is fused with adjacent cyclic structure(s) at any position(s);

[0236] p is 1, 2, 3, or 4;

[0237] when p is 2, 3, or 4, a plurality of cyclic structures A are mutually the same or different; and

[0238] * represents a bonding portion to a carbon atom of a benzene ring in the formula (2).

##STR00105##

[0239] In the formula (2c):

[0240] R.sub.2001 to R.sub.2008 are each independently a hydrogen atom or a substituent, or at least one pair of a pair of R.sub.2001 and R.sub.2002, a pair of R.sub.2002 and R.sub.2003, a pair of R.sub.2003 and R.sub.2004, a pair of R.sub.2005 and R.sub.2006, a pair of R.sub.2006 and R.sub.2007, or a pair of R.sub.2007 and R.sub.2008 are bonded to each other to form a ring;

[0241] R.sub.2001 to R.sub.2008 as the substituents each independently represent the same as R.sub.1 to R.sub.8 as the substituents in the formula (2a);

[0242] B represents a cyclic structure represented by the formula (211) or (212), and the cyclic structure B is fused with adjacent cyclic structure(s) at any position(s);

[0243] px is 1, 2, 3, or 4;

[0244] when px is 2, 3, or 4, a plurality of cyclic structures B are mutually the same or different;

[0245] C represents a cyclic structure represented by the formula (211) or (212), and the cyclic structure C is fused with adjacent cyclic structure(s) at any position(s);

[0246] py is 1, 2, 3, or 4;

[0247] when py is 2, 3, or 4, a plurality of cyclic structures C are mutually the same or different; and

[0248] * represents a bonding portion to a carbon atom of a benzene ring in the formula (2).

##STR00106##

[0249] In the formula (211), R.sub.2009 and R.sub.2010 are each independently a hydrogen atom or a substituent, or bonded to a part of an adjacent cyclic structure to form a ring, or a pair of R.sub.2009 and R.sub.2010 are mutually bonded to form a ring;

[0250] in the formula (212), X.sub.201 is CR.sub.2011R.sub.2012, NR.sub.2013, a sulfur atom, or an oxygen atom, and R.sub.2011, R.sub.2012 and R.sub.2013 are each independently a hydrogen atom or a substituent, or R.sub.2011 and R.sub.2012 are mutually bonded to form a ring; and

[0251] R.sub.2009, R.sub.2010, R.sub.2011, R.sub.2012 and R.sub.2013 as the substituents each independently represent the same as R.sub.1 to R.sub.8 as the substituents in the formula (2a).

[0252] In the formula (211), R.sub.2009 and R.sub.2010 are each independently bonded to a part of an adjacent cyclic structure to form a ring, which specifically means any of (I) to (IV) below.

[0253] In the formula (211), a pair of R.sub.2009 and R.sub.2010 are mutually bonded to form a ring, which specifically means (V) below.

(I) When the cyclic structures represented by the formula (211) are adjacent to each other, between the two adjacent rings, at least one pair of the following are mutually bonded to form a ring: R.sub.2009 of one of the rings and R.sub.2009 of the other of the rings; R.sub.2009 of one of the rings and R.sub.2010 of the other of the rings; or R.sub.2010 of one of the rings and R.sub.2010 of the other of the rings.
(II) When the cyclic structure represented by the formula (211) and the benzene ring having R.sub.25 to R.sub.28 in the formula (2b) are adjacent to each other, between the two adjacent rings, at least one pair of the following are mutually bonded to form a ring: R.sub.209 of one of the rings and R.sub.25 of the other of the rings; R.sub.209 of one of the rings and R.sub.28 of the other of the rings; R.sub.210 of one of the rings and R.sub.25 of the other of the rings; or R.sub.210 of one of the rings and R.sub.28 of the other of the rings.
(III) When the cyclic structure represented by the formula (211) and the benzene ring having R.sub.2001 to R.sub.2004 in the formula (2c) are adjacent to each other, between the two adjacent rings, at least one pair of the following are mutually bonded to form a ring: R.sub.2009 of one of the rings and R.sub.2001 of the other of the rings; R.sub.2009 of one of the rings and R.sub.2004 of the other of the rings; R.sub.2010 of one of the rings and R.sub.2001 of the other of the rings; or R.sub.2010 of one of the rings and R.sub.2004 of the other of the rings.
(IV) When the cyclic structure represented by the formula (211) and the benzene ring having R.sub.2005 to R.sub.2008 in the formula (2c) are adjacent to each other, between the two adjacent rings, at least one pair of the following are mutually bonded to form a ring: R.sub.2009 of one of the rings and R.sub.2005 of the other of the rings; R.sub.2009 of one of the rings and R.sub.2008 of the other of the rings; R.sub.2010 of one of the rings and R.sub.2000 of the other of the rings; or R.sub.2010 of one of the rings and R.sub.2008 of the other of the rings.
(V) The pair of R.sub.2009 and R.sub.2010 of the cyclic structure represented by the formula (211) are mutually bonded to form a ring. In other words, (V) means that the pair of R.sub.2009 and R.sub.2010 bonded to the same ring are mutually bonded to form a ring.

[0254] In the compound M2 of the exemplary embodiment, it is preferable that each Rx is independently a hydrogen atom, an unsubstituted aryl group having 6 to 30 ring carbon atoms, an unsubstituted heterocyclic group having 5 to 30 ring atoms, or an unsubstituted alkyl group having 1 to 30 carbon atoms; and

[0255] when Rx is an unsubstituted heterocyclic group having 5 to 30 ring atoms, Rx as the unsubstituted heterocyclic group having 5 to 30 ring atoms is a pyridyl group, pyrimidinyl group, triazinyl group, dibenzofuranyl group, or dibenzothienyl group.

[0256] Herein, the triazinyl group refers to a group obtained by excluding one hydrogen atom from 1,3,5-triazine, 1,2,4-triazine, or 1,2,3-triazine.

[0257] The triazinyl group is preferably a group obtained by excluding one hydrogen atom from 1,3,5-triazine.

[0258] In the compound M2 of the exemplary embodiment, it is more preferable that each Rx is independently a hydrogen atom, an unsubstituted aryl group having 6 to 30 ring carbon atoms, an unsubstituted dibenzofuranyl group, or an unsubstituted dibenzothienyl group.

[0259] In the compound M2 of the exemplary embodiment, Rx is further preferably a hydrogen atom.

[0260] In the compound M2 of the exemplary embodiment, when any one or more Rx are hydrogen atoms, it is preferable that all the hydrogen atoms are protium atoms, at least one of the hydrogen atoms is a deuterium atom, or all the hydrogen atoms are deuterium.

[0261] In the compound M2 of the exemplary embodiment, when any one or more Rx are substituents and the substituents have one or more hydrogen atoms, it is preferable that all the hydrogen atoms are protium atoms, at least one of the hydrogen atoms is a deuterium atom, or all the hydrogen atoms are deuterium atoms.

[0262] In the compound M2 of the exemplary embodiment, it is preferable that R.sub.1 to R.sub.8, R.sub.21 to R.sub.28, R.sub.2001 to R.sub.2008, R.sub.2009 to R.sub.2010 and R.sub.2011 to R.sub.2013 as the substituents are each independently an unsubstituted aryl group having 6 to 30 ring carbon atoms, an unsubstituted heterocyclic group having 5 to 30 ring atoms, or an unsubstituted alkyl group having 1 to 30 carbon atoms.

[0263] In the compound M2 of the exemplary embodiment, it is preferable that R.sub.101 to R.sub.150 and R.sub.61 to R.sub.70 as the substituents are each independently an unsubstituted aryl group having 6 to 14 ring carbon atoms, an unsubstituted heterocyclic group having 5 to 14 ring atoms, or an unsubstituted alkyl group having 1 to 6 carbon atoms, and

[0264] Rx.sub.21 to Rx.sub.26 serving as the substituents are each independently an unsubstituted aryl group having 6 to 14 ring carbon atoms, or an unsubstituted heterocyclic group having 5 to 14 ring atoms.

[0265] In the compound M2 of the exemplary embodiment, it is also preferable that R.sub.11 to R.sub.150 and R.sub.61 to R.sub.70 are hydrogen atoms, and

[0266] Rx.sub.21 to Rx.sub.26 serving as the substituents are each independently an unsubstituted aryl group having 6 to 14 ring carbon atoms or an unsubstituted heterocyclic group having 5 to 14 ring atoms.

[0267] In the compound M2 of the exemplary embodiment, it is preferable that R.sub.201 to R.sub.260 as the substituents are each independently a halogen atom, an unsubstituted aryl group having 6 to 14 ring carbon atoms, an unsubstituted heterocyclic group having 5 to 14 ring atoms, or an unsubstituted alkyl group having 1 to 6 carbon atoms; and

[0268] Rx.sub.27 and Rx.sub.28 serving as the substituents are each independently an unsubstituted aryl group having 6 to 14 ring carbon atoms or an unsubstituted alkyl group having 1 to 6 carbon atoms.

[0269] In the compound M2 of the exemplary embodiment, it is more preferable that R.sub.201 to R.sub.260 as the substituents are each independently an unsubstituted aryl group having 6 to 14 ring carbon atoms, an unsubstituted heterocyclic group having 5 to 14 ring atoms, or an unsubstituted alkyl group having 1 to 6 carbon atoms; and

[0270] Rx.sub.27 and Rx.sub.28 serving as the substituents are each independently an unsubstituted aryl group having 6 to 14 ring carbon atoms or an unsubstituted alkyl group having 1 to 6 carbon atoms.

[0271] In the compound M2 of the exemplary embodiment, it is also preferable that R.sub.201 to R.sub.260 are hydrogen atoms, and

[0272] Rx.sub.27 and Rx.sub.28 serving as the substituents are each independently an unsubstituted aryl group having 6 to 14 ring carbon atoms or an unsubstituted alkyl group having 1 to 6 carbon atoms.

[0273] In the compound M2 of the exemplary embodiment, when any one or more of R.sub.101 to R.sub.150, R.sub.61 to R.sub.70, and R.sub.201 to R.sub.260 are hydrogen atoms, it is preferable that all the hydrogen atoms are protium atoms, at least one of the hydrogen atoms is a deuterium atom, or all the hydrogen atoms are deuterium.

[0274] In the compound M2 of the exemplary embodiment, when any one or more of R.sub.101 to R.sub.150, R.sub.61 to R.sub.70, and R.sub.201 to R.sub.260 are substituents and the substituents have one or more hydrogen atoms, it is preferable that all the hydrogen atoms are protium atoms, at least one of the hydrogen atoms is a deuterium atom, or all the hydrogen atoms are deuterium atoms.

[0275] In the compound M2 of the exemplary embodiment, D.sub.1 is preferably any one of groups represented by formulae (D-21) to (D-37) below.

Groups Represented by Formulae (D-21) to (D-25)

[0276] ##STR00107##

[0277] In the formulae (D-21) to (D-25), R.sub.171 to R.sub.200 and R.sub.71 to R.sub.90 are each independently a hydrogen atom or a substituent, or at least one pair of the following are mutually bonded to form a ring: a pair of R.sub.171 and R.sub.172, a pair of R.sub.172 and R.sub.173, a pair of R.sub.173 and R.sub.174, a pair of R.sub.174 and R.sub.175, a pair of R.sub.175 and R.sub.176, a pair of R.sub.177 and R.sub.178, a pair of R.sub.178 and R.sub.179, a pair of R.sub.179 and R.sub.180, a pair of R.sub.181 and R.sub.182, a pair of R.sub.182 and R.sub.183, a pair of R.sub.183 and R.sub.184, a pair of R.sub.185 and R.sub.186, a pair of R.sub.186 and R.sub.187, a pair of R.sub.187 and R.sub.188, a pair of R.sub.188 and R.sub.189, a pair of R.sub.189 and R.sub.190, a pair of R.sub.191 and R.sub.192, a pair of R.sub.192 and R.sub.193, a pair of R.sub.193 and R.sub.194, a pair of R.sub.194 and R.sub.195, a pair of R.sub.195 and R.sub.196, a pair of R.sub.197 and R.sub.198, a pair of R.sub.198 and R.sub.199, a pair of R.sub.199 and R.sub.200, a pair of R.sub.71 and R.sub.72, a pair of R.sub.72 and R.sub.73, a pair of R.sub.73 and R.sub.74, a pair of R.sub.75 and R.sub.76, a pair of R.sub.76 and R.sub.77, a pair of R.sub.77 and R.sub.78, a pair of R.sub.79 and R.sub.80, a pair of R.sub.80 and R.sub.81, or a pair of R.sub.81 and R.sub.82;

[0278] R.sub.171 to R.sub.200 and R.sub.71 to R.sub.90 serving as the substituents are each independently a halogen atom, a substituted or unsubstituted aryl group having 6 to 14 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 14 ring atoms, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 6 carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 6 carbon atoms, a hydroxy group, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy halide group having 1 to 6 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 14 ring carbon atoms, a substituted or unsubstituted alkylamino group having 2 to 12 carbon atoms, a thiol group, a substituted or unsubstituted alkylthio group having 1 to 6 carbon atoms, or a substituted or unsubstituted arylthio group having 6 to 14 ring carbon atoms; and

[0279] * represents a bonding portion to a carbon atom of a benzene ring in the formula (2).

[0280] In the compound M2 of the exemplary embodiment, R.sub.171 to R.sub.200 and R.sub.71 to R.sub.90 serving as the substituents are preferably each independently an unsubstituted aryl group having 6 to 14 ring carbon atoms, an unsubstituted heterocyclic group having 5 to 14 ring atoms, or an unsubstituted alkyl group having 1 to 6 carbon atoms.

[0281] In the compound M2 of the exemplary embodiment, R.sub.171 to R.sub.200 and R.sub.71 to R.sub.90 are also preferably hydrogen atoms.

[0282] In the compound M2 of the exemplary embodiment, when any one or more of R.sub.171 to R.sub.200 and R.sub.71 to R.sub.90 are hydrogen atoms, it is preferable that all the hydrogen atoms are protium atoms, at least one of the hydrogen atoms is a deuterium atom, or all the hydrogen atoms are deuterium.

[0283] In the compound M2 of the exemplary embodiment, when any one or more of R.sub.171 to R.sub.200 and R.sub.71 to R.sub.90 are substituents and the substituents have one or more hydrogen atoms, it is preferable that all the hydrogen atoms are protium atoms, at least one of the hydrogen atoms is a deuterium atom, or all the hydrogen atoms are deuterium atoms.

[0284] The groups represented by the formulae (D-21) to (D-25) are each preferably any one of groups represented by formulae (2-5) to (2-17) below.

##STR00108## ##STR00109##

[0285] In the formulae (2-5) to (2-17), * represents a bonding portion to a carbon atom of a benzene ring in the formula (2), and D represents a deuterium atom.

Groups Represented by Formulae (D-26) to (D-31)

[0286] ##STR00110## ##STR00111##

[0287] In the formulae (D-26) to (D-31), R.sub.11 to R.sub.16 are each a substituent, R.sub.101 to R.sub.150 and R.sub.61 to R.sub.70 are each independently a hydrogen atom or a substituent, or at least one pair of the following are mutually bonded to form a ring: a pair of R.sub.101 and R.sub.102, a pair of R.sub.102 and R.sub.103, a pair of R.sub.103 and R.sub.104, a pair of R.sub.105 and R.sub.106, a pair of R.sub.107 and R.sub.108, a pair of R.sub.108 and R.sub.109, a pair of R.sub.109 and R.sub.110, a pair of R.sub.111 and R.sub.112, a pair of R.sub.112 and R.sub.113, a pair of R.sub.113 and R.sub.114, a pair of R.sub.116 and R.sub.117, a pair of R.sub.117 and R.sub.118, a pair of R.sub.118 and R.sub.119, a pair of R.sub.121 and R.sub.122, a pair of R.sub.122 and R.sub.123, a pair of R.sub.123 and R.sub.124, a pair of R.sub.126 and R.sub.127, a pair of R.sub.127 and R.sub.128, a pair of R.sub.128 and R.sub.129, a pair of R.sub.131 and R.sub.132, a pair of R.sub.132 and R.sub.133, a pair of R.sub.133 and R.sub.134, a pair of R.sub.135 and R.sub.136, a pair of R.sub.136 and R.sub.137, a pair of R.sub.137 and R.sub.138, a pair of R.sub.139 and R.sub.140, a pair of R.sub.141 and R.sub.142, a pair of R.sub.142 and R.sub.143, a pair of R.sub.143 and R.sub.144, a pair of R.sub.145 and R.sub.146, a pair of R.sub.146 and R.sub.147, a pair of R.sub.147 and R.sub.148, a pair of R.sub.149 and R.sub.150, a pair of R.sub.61 and R.sub.62, a pair of R.sub.62 and R.sub.63, a pair of R.sub.63 and R.sub.64, a pair of R.sub.65 and R.sub.66, a pair of R.sub.67 and R.sub.68, a pair of R.sub.68 and R.sub.69, or a pair of R.sub.69 and R.sub.70;

[0288] R.sub.101 to R.sub.150 and R.sub.61 to R.sub.70 as the substituents are each independently a substituted or unsubstituted aryl group having 6 to 14 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 14 ring atoms, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 6 carbon atoms, a hydroxy group, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 14 ring carbon atoms, a substituted or unsubstituted arylamino group having 6 to 28 ring carbon atoms, a substituted or unsubstituted alkylamino group having 2 to 12 carbon atoms, a thiol group, a substituted or unsubstituted alkylthio group having 1 to 6 carbon atoms, or a substituted or unsubstituted arylthio group having 6 to 14 ring carbon atoms;

[0289] R.sub.11 to R.sub.16 as the substituents are each independently a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 14 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 14 ring atoms, a substituted or unsubstituted alkylsilyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 14 ring carbon atoms, a substituted or unsubstituted alkylamino group having 2 to 12 carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 6 carbon atoms, or a substituted or unsubstituted arylthio group having 6 to 14 ring carbon atoms; and

[0290] * represents a bonding portion to a carbon atom of a benzene ring in the formula (2).

[0291] In the compound M2 of the exemplary embodiment, R.sub.101 to R.sub.150 and R.sub.61 to R.sub.70 serving as the substituents are preferably each independently an unsubstituted aryl group having 6 to 14 ring carbon atoms, an unsubstituted heterocyclic group having 5 to 14 ring atoms, or an unsubstituted alkyl group having 1 to 6 carbon atoms, and

[0292] R.sub.11 to R.sub.16 serving as the substituents are preferably each independently an unsubstituted aryl group having 6 to 14 ring carbon atoms or an unsubstituted heterocyclic group having 5 to 14 ring atoms.

[0293] In the compound M2 of the exemplary embodiment, it is also preferable that R.sub.101 to R.sub.150 and R.sub.61 to R.sub.70 are hydrogen atoms, and R.sub.11 to R.sub.16 serving as the substituents are each independently an unsubstituted aryl group having 6 to 14 ring carbon atoms or an unsubstituted heterocyclic group having 5 to 14 ring atoms.

[0294] In the compound M2 of the exemplary embodiment, when any one or more of R.sub.101 to R.sub.150 and R.sub.61 to R.sub.70 are hydrogen atoms, it is preferable that all the hydrogen atoms are protium atoms, at least one of the hydrogen atoms is a deuterium atom, or all the hydrogen atoms are deuterium.

[0295] In the compound M2 of the exemplary embodiment, when any one or more of R.sub.11 to R.sub.16, R.sub.101 to R.sub.150, and R.sub.61 to R.sub.70 are substituents and the substituents have one or more hydrogen atoms, it is preferable that all the hydrogen atoms are protium atoms, at least one of the hydrogen atoms is a deuterium atom, or all the hydrogen atoms are deuterium atoms.

Groups Represented by Formulae (D-32) to (D-37)

[0296] ##STR00112## ##STR00113##

[0297] In the formulae (D-32) to (D-37), X.sub.1 to X.sub.6 are each independently an oxygen atom, a sulfur atom, or CR.sub.151R.sub.152;

[0298] R.sub.151 and R.sub.152 are each independently a hydrogen atom or a substituent, or R.sub.151 and R.sub.152 are bonded to each other to form a ring;

[0299] R.sub.201 to R.sub.260 are each independently a hydrogen atom or a substituent, or at least one pair of a pair of R.sub.201 and R.sub.202, a pair of R.sub.202 and R.sub.203, a pair of R.sub.203 and R.sub.204, a pair of R.sub.205 and R.sub.206, a pair of R.sub.207 and R.sub.208, a pair of R.sub.208 and R.sub.209, a pair of R.sub.209 and R.sub.210, a pair of R.sub.211 and R.sub.212, a pair of R.sub.212 and R.sub.213, a pair of R.sub.213 and R.sub.214, a pair of R.sub.216 and R.sub.217, a pair of R.sub.217 and R.sub.218, a pair of R.sub.218 and R.sub.219, a pair of R.sub.221 and R.sub.222, a pair of R.sub.222 and R.sub.223, a pair of R.sub.223 and R.sub.224, a pair of R.sub.226 and R.sub.227, a pair of R.sub.227 and R.sub.228, a pair of R.sub.228 and R.sub.229, a pair of R.sub.231 and R.sub.232, a pair of R.sub.232 and R.sub.233, a pair of R.sub.233 and R.sub.234, a pair of R.sub.235 and R.sub.236, a pair of R.sub.236 and R.sub.237, a pair of R.sub.237 and R.sub.238, a pair of R.sub.239 and R.sub.240, a pair of R.sub.241 and R.sub.242, a pair of R.sub.242 and R.sub.243, a pair of R.sub.243 and R.sub.244, a pair of R.sub.245 and R.sub.246, a pair of R.sub.246 and R.sub.247, a pair of R.sub.247 and R.sub.248, a pair of R.sub.249 and R.sub.250, a pair of R.sub.251 and R.sub.252, a pair of R.sub.252 and R.sub.253, a pair of R.sub.253 and R.sub.254, a pair of R.sub.255 and R.sub.256, a pair of R.sub.257 and R.sub.258, a pair of R.sub.258 and R.sub.259, or a pair of R.sub.259 and R.sub.260 are bonded to each other to form a ring;

[0300] R.sub.151, R.sub.152, and R.sub.201 to R.sub.260 serving as the substituents are each independently a halogen atom, a substituted or unsubstituted aryl group having 6 to 14 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 14 ring atoms, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 6 carbon atoms, a hydroxy group, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy halide group having 1 to 6 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 14 ring carbon atoms, a substituted or unsubstituted arylamino group having 6 to 28 ring carbon atoms, a substituted or unsubstituted alkylamino group having 2 to 12 carbon atoms, a thiol group, a substituted or unsubstituted alkylthio group having 1 to 6 carbon atoms, or a substituted or unsubstituted arylthio group having 6 to 14 ring carbon atoms, and

[0301] * represents a bonding portion to a carbon atom of a benzene ring in the formula (2).

[0302] In the compound M2 of the exemplary embodiment, R.sub.201 to R.sub.260 serving as the substituents are preferably each independently a halogen atom, an unsubstituted aryl group having 6 to 14 ring carbon atoms, an unsubstituted heterocyclic group having 5 to 14 ring atoms, or an unsubstituted alkyl group having 1 to 6 carbon atoms, and

[0303] R.sub.151 and R.sub.152 serving as the substituents are preferably each independently an unsubstituted aryl group having 6 to 14 ring carbon atoms or an unsubstituted alkyl group having 1 to 6 carbon atoms.

[0304] In the compound M2 of the exemplary embodiment, it is more preferable that R.sub.201 to R.sub.260 serving as the substituents are each independently an unsubstituted aryl group having 6 to 14 ring carbon atoms, an unsubstituted heterocyclic group having 5 to 14 ring atoms, or an unsubstituted alkyl group having 1 to 6 carbon atoms, and

[0305] R.sub.151 and R.sub.152 serving as the substituents are each independently an unsubstituted aryl group having 6 to 14 ring carbon atoms or an unsubstituted alkyl group having 1 to 6 carbon atoms.

[0306] In the compound M2 of the exemplary embodiment, it is also preferable that R.sub.201 to R.sub.260 are hydrogen atoms, and

[0307] R.sub.151 and R.sub.152 serving as the substituents are each independently an unsubstituted aryl group having 6 to 14 ring carbon atoms or an unsubstituted alkyl group having 1 to 6 carbon atoms.

[0308] In the compound M2 of the exemplary embodiment, when any one or more of R.sub.151, R.sub.152, and R.sub.201 to R.sub.260 are hydrogen atoms, it is preferable that all the hydrogen atoms are protium atoms, at least one of the hydrogen atoms is a deuterium atom, or all the hydrogen atoms are deuterium.

[0309] In the compound M2 of the exemplary embodiment, when any one or more of R.sub.151, R.sub.152, and R.sub.201 to R.sub.260 are substituents and the substituents have one or more hydrogen atoms, it is preferable that all the hydrogen atoms are protium atoms, at least one of the hydrogen atoms is a deuterium atom, or all the hydrogen atoms are deuterium atoms.

Compound Represented by Formula (22)

[0310] ##STR00114##

[0311] In the formula (22):

[0312] Ar.sub.1 is a group selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, a substituted silyl group, a cyano group, a nitro group, a carboxy group, and groups represented by formulae (1a) to (1j) below;

[0313] Ar.sub.EWG is a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms that has one or more nitrogen atoms in a ring, or an aryl group having 6 to 30 ring carbon atoms that is substituted with one or more cyano groups;

[0314] each Ar.sub.X is independently a hydrogen atom or a substituent, Ar.sub.X serving as the substituent being a group selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, a substituted silyl group, a cyano group, a nitro group, a carboxy group, and groups represented by the formulae (1a) to (1j) below;

[0315] n is 0, 1, 2, 3, 4, or 5 and when n is 2, 3, 4, or 5, a plurality of Ar.sub.X are mutually the same or different;

[0316] a ring (A) is a substituted or unsubstituted aromatic hydrocarbon ring or a substituted or unsubstituted heterocycle, the ring (A) is a five-membered ring, a six-membered ring, or a seven-membered ring, and Ar.sub.EWG, Ar.sub.1 and Ar.sub.X are each bonded to an element forming the ring (A); and

[0317] at least one of Ar.sub.1 or Ar.sub.X is a group selected from the group consisting of groups represented by the formulae (1a) to (1j).

##STR00115## ##STR00116##

[0318] In the formulae (1a) to (1j), X.sub.1 to X.sub.20 are each independently a nitrogen atom (N) or a carbon atom bonded to R.sub.A1 (C—R.sub.A1).

[0319] In the formula (1b), one of X.sub.5 to X.sub.8 is a carbon atom bonded to one of X.sub.9 to X.sub.12, and one of X.sub.9 to X.sub.12 is a carbon atom bonded to one of X.sub.5 to X.sub.8.

[0320] In the formula (1c), one of X.sub.5 to X.sub.8 is a carbon atom bonded to a nitrogen atom in a ring including A2.

[0321] In the formula (1e), one of X.sub.5 to X.sub.8 and X.sub.18 is a carbon atom bonded to one of X.sub.9 to X.sub.12, and one of X.sub.9 to X.sub.12 is a carbon atom bonded to one of X.sub.5 to X.sub.8 and X.sub.18.

[0322] In the formula (1f), one of X.sub.5 to X.sub.8 and X.sub.18 is a carbon atom bonded to one of X.sub.9 to X.sub.12 and X.sub.19, and one of X.sub.9 to X.sub.12 and X.sub.19 is a carbon atom bonded to one of X.sub.5 to X.sub.8 and X.sub.18.

[0323] In the formula (1g), one of X.sub.5 to X.sub.8 is a carbon atom bonded to one of X.sub.9 to X.sub.12 and X.sub.19, and one of X.sub.9 to X.sub.12 and X.sub.19 is a carbon atom bonded to one of X.sub.5 to X.sub.8.

[0324] In the formula (1h), one of X.sub.5 to X.sub.8 and X.sub.18 is a carbon atom bonded to a nitrogen atom in a ring including A2.

[0325] In the formula (1i), one of X.sub.5 to X.sub.8 and X.sub.18 is a carbon atom bonded to a nitrogen atom linking a ring including X.sub.9 to X.sub.12 and X.sub.19 with a ring including X.sub.13 to X.sub.16 and X.sub.20.

[0326] In the formula (1j), one of X.sub.5 to X.sub.8 is a carbon atom bonded to a nitrogen atom linking a ring including X.sub.9 to X.sub.12 and X.sub.19 with a ring including X.sub.13 to X.sub.16 and X.sub.20.

[0327] each R.sub.A1 is independently a hydrogen atom or a substituent, or at least one pair of pairs of a plurality of R.sub.A1 are mutually directly bonded to form a ring or are bonded through a hetero atom to form a ring;

[0328] R.sub.A1 as the substituent is a group selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, a substituted silyl group, a cyano group, a nitro group, and a carboxy group.

[0329] A plurality of R.sub.A1 as the substituents are mutually the same or different.

[0330] In the formula (1a), when X.sub.1 to X.sub.8 are each a carbon atom bonded to R.sub.A1 (C—R.sub.A1), a plurality of R.sub.A1 preferably form no ring.

[0331] When any one or more of R.sub.A1 are hydrogen atoms, it is preferable that all the hydrogen atoms are protium atoms, at least one of the hydrogen atoms is a deuterium atom, or all the hydrogen atoms are deuterium.

[0332] When any one or more of R.sub.A1 are substituents and the substituents have one or more hydrogen atoms, it is preferable that all the hydrogen atoms are protium atoms, at least one of the hydrogen atoms is a deuterium atom, or all the hydrogen atoms are deuterium atoms.

[0333] In the formulae (1a) to (1j), * represents a bonding portion to the ring (A).

[0334] In the formulae (1a) to (1j):

[0335] A.sub.1 and A.sub.2 are each independently a single bond, an oxygen atom (O), a sulfur atom (S), C(R.sub.2021)(R.sub.2022), Si(R.sub.2023)(R.sub.2024), C(═O), S(═O), SO.sub.2, or N(R.sub.2025);

[0336] R.sub.2021 to R.sub.2025 are each independently a hydrogen atom or a substituent; and

[0337] R.sub.2021 to R.sub.2025 as the substituents are each independently a group selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, a substituted silyl group, a cyano group, a nitro group, and a carboxy group.

[0338] In the formulae (1a) to (1j), Ara is a group selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, and a substituted silyl group.

[0339] Ara is preferably a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms or a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms.

[0340] The formula (1a) is represented by a formula (1aa) below when A.sub.1 is a single bond, represented by a formula (1ab) below when A.sub.1 is an oxygen atom, represented by a formula (1ac) below when A.sub.1 is a sulfur atom, represented by a formula (1ad) below when A.sub.1 is C(R.sub.2021)(R.sub.2022), represented by a formula (1ae) below when A.sub.1 is Si(R.sub.2023)(R.sub.2024), represented by a formula (1af) below when A.sub.1 is C(═O), represented by a formula (1ag) below when A.sub.1 is S(═O), represented by a formula (1ah) below when A.sub.1 is SO.sub.2, and represented by a formula (1ai) below when A.sub.1 is N(R.sub.2025). In the formulae (1aa) to (1ai), X.sub.1 to X.sub.8 and R.sub.2021 to R.sub.2025 represent the same as above. Also in the formulae (1b), (1c), (1e), and (1g) to (1j), linkages between rings via A.sub.1 and A.sub.2 are the same as those in the formulae (1aa) to (1ai). In the formula (1aa), when X.sub.1 to X.sub.8 are each a carbon atom bonded to R.sub.A1 (C—R.sub.A1), a plurality of R.sub.A1 serving as the substituents preferably form no ring.

##STR00117## ##STR00118##

[0341] The compound M2 is also preferably represented by a formula (221) below.

##STR00119##

[0342] In the formula (221), Ar.sub.1, Ar.sub.EWG, Ar.sub.x, n and a ring (A) respectively represent the same as Ar.sub.1, Ar.sub.EWG, Ar.sub.x, n and the ring (A) in the formula (22).

[0343] The compound M2 is also preferably represented by a formula (222) below.

##STR00120##

[0344] In the formula (222):

[0345] Y.sub.1 to Y.sub.5 are each independently a nitrogen atom (N), a carbon atom bonded to a cyano group (C—CN), or a carbon atom bonded to R.sub.A2 (C—R.sub.A2);

[0346] at least one of Y.sub.1 to Y.sub.5 is N or C—CN;

[0347] a plurality of R.sub.A2 are mutually the same or different;

[0348] each R.sub.A2 is independently a hydrogen atom or a substituent, R.sub.A2 serving as the substituent being a group selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, a substituted silyl group, a cyano group, a nitro group, and a carboxy group; and

[0349] a plurality of R.sub.A2 are mutually the same or different.

[0350] In the formula (222), Ar.sub.1 represents the same as Ar.sub.1 in the formula (22).

[0351] In the formula (222), Ar.sub.2 to Ar.sub.5 are each independently a hydrogen atom or a substituent, Ar.sub.2 to Ar.sub.5 serving as the substituents being each independently a group selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, a substituted silyl group, a cyano group, a nitro group, a carboxy group, and groups represented by the formulae (1a) to (1c).

[0352] In the formula (222), when any one or more of Ar.sub.2 to Ar.sub.5 are hydrogen atoms, it is preferable that all the hydrogen atoms are protium atoms, at least one of the hydrogen atoms is a deuterium atom, or all the hydrogen atoms are deuterium.

[0353] In the formula (222), when any one or more of Ar.sub.2 to Ar.sub.5 are substituents and the substituents have one or more hydrogen atoms, it is preferable that all the hydrogen atoms are protium atoms, at least one of the hydrogen atoms is a deuterium atom, or all the hydrogen atoms are deuterium atoms.

[0354] In the formula (222), at least one of Ar.sub.1 to Ar.sub.5 is a group selected from the group consisting of groups represented by the formulae (1a) to (1c).

[0355] The compound M2 is also preferably a compound represented by a formula (11aa), (11bb) or (11cc) below.

##STR00121##

[0356] In the formulae (11aa), (11bb), and (11cc), Y.sub.1 to Y.sub.5, R.sub.A2, Ar.sub.2 to Ar.sub.5, X.sub.1 to X.sub.16, R.sub.A1, and Ara represent the same as above-described Y.sub.1 to Y.sub.5, R.sub.A2, Ar.sub.2 to Ar.sub.5, X.sub.1 to X.sub.16, R.sub.A1, and Ara, respectively.

[0357] The compound M2 is exemplified, for instance, by a compound represented by a formula (23) below.

##STR00122##

[0358] In the formula (23):

[0359] Az is a cyclic structure selected from the group consisting of a substituted or unsubstituted pyridine ring, a substituted or unsubstituted pyrimidine ring, a substituted or unsubstituted triazine ring, and a substituted or unsubstituted pyrazine ring;

[0360] c is 0, 1, 2, 3, 4 or 5;

[0361] when c is 0, Cz and Az are bonded to each other with a single bond;

[0362] when c is 1, 2, 3, 4 or 5, L.sub.23 is a linking group selected from the group consisting of a substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms, and a substituted or unsubstituted heteroarylene group having 5 to 30 ring atoms;

[0363] when c is 2, 3, 4, or 5, a plurality of L.sub.23 are mutually the same or different;

[0364] the plurality of L.sub.23 are mutually bonded to form a ring or not bonded to form no ring; and

[0365] Cz is represented by a formula (23a) below.

##STR00123##

[0366] In the formula (23a):

[0367] Y.sub.21 to Y.sub.28 are each independently a nitrogen atom or CR.sub.A3;

[0368] each R.sub.A3 is independently a hydrogen atom or a substituent, or at least one pair of pairs of a plurality of R.sub.A3 are mutually bonded to form a ring;

[0369] each R.sub.A3 serving as the substituent is independently a group selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, a substituted silyl group; a cyano group, a nitro group, and a carboxy group,

[0370] a plurality of R.sub.A3 are mutually the same or different; and

[0371] *1 represents a bonding portion to a carbon atom in a structure of a linking group represented by L.sub.23 or a bonding portion to a carbon atom in a cyclic structure represented by Az.

[0372] Y.sub.21 to Y.sub.28 are also preferably CR.sub.A3.

[0373] c in the formula (23) is preferably 0 or 1.

[0374] Cz is also preferably represented by a formula (23b), a formula (23c), or a formula (23d) below.

##STR00124## ##STR00125##

[0375] In the formulae (23b), (23c), and (23d), Y.sub.21 to Y.sub.28 and Y.sub.51 to Y.sub.58 are each independently a nitrogen atom or CR.sub.A4;

[0376] in the formula (23b), at least one of Y.sub.25 to Y.sub.28 is a carbon atom bonded to one of Y.sub.51 to Y.sub.54, and at least one of Y.sub.51 to Y.sub.54 is a carbon atom bonded to one of Y.sub.25 to Y.sub.28;

[0377] in the formula (23c), at least one of Y.sub.25 to Y.sub.28 is a carbon atom bonded to a nitrogen atom in a five-membered ring of a nitrogen-containing fused ring including Y.sub.51 to Y.sub.58;

[0378] in the formula (23d), *a and *b each represent a bonding portion to one of Y.sub.21 to Y.sub.28, at least one of Y.sub.25 to Y.sub.28 is a bonding portion represented by *a, and at least one of Y.sub.25 to Y.sub.28 is a bonding portion represented by *b;

[0379] n is 1, 2, 3 or 4;

[0380] each R.sub.A4 is independently a hydrogen atom or a substituent, or at least one pair of pairs of a plurality of R.sub.A4 are mutually bonded to form a ring;

[0381] each R.sub.A4 serving as the substituent is independently a substituent selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, a substituted silyl group; a cyano group, a nitro group, and a carboxy group,

[0382] a plurality of R.sub.A4 are mutually the same or different;

[0383] Z.sub.21 and Z.sub.22 are each independently one selected from the group consisting of an oxygen atom, a sulfur atom, NR.sub.45, and CR.sub.46R.sub.47;

[0384] R.sub.45 is a hydrogen atom or a substituent;

[0385] R.sub.46 and R.sub.47 are each independently a hydrogen atom or a substituent, or a pair of R.sub.46 and R.sub.47 are mutually bonded to form a ring; R.sub.45, R.sub.46, and R.sub.47 serving as the substituents are each independently a substituent selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, a substituted silyl group, a cyano group, a nitro group, and a carboxy group;

[0386] a plurality of R.sub.45 are mutually the same or different;

[0387] a plurality of R.sub.46 are mutually the same or different;

[0388] a plurality of R.sub.47 are mutually the same or different; and

[0389] * represents a bonding portion to a carbon atom in a structure of a linking group represented by L.sub.23, or a bonding portion to a carbon atom in a cyclic structure represented by Az.

[0390] Z.sub.21 is preferably NR.sub.45.

[0391] When Z.sub.21 is NR.sub.45, R.sub.45 is preferably a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms.

[0392] Z.sub.22 is preferably NR.sub.45.

[0393] When Z.sub.22 is NR.sub.45, R.sub.45 is preferably a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms.

[0394] Y.sub.51 to Y.sub.58 are preferably CR.sub.A4. In this case, at least one of Y.sub.51 to Y.sub.58 is a carbon atom bonded to a cyclic structure represented by the formula (23a).

[0395] Cz is also preferably represented by the formula (23d) in which n is 1.

[0396] Az is preferably a cyclic structure selected from the group consisting of a substituted or unsubstituted pyrimidine ring and a substituted or unsubstituted triazine ring.

[0397] Az is more preferably a cyclic structure selected from the group consisting of a substituted pyrimidine ring and a substituted triazine ring, in which a substituent of each of the substituted pyrimidine ring and the substituted triazine ring is a group selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms and a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, further preferably a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms.

[0398] When the pyrimidine ring and the triazine ring as Az have a substituted or unsubstituted aryl group as a substituent, the aryl group preferably has 6 to 20 ring carbon atoms, more preferably 6 to 14 ring carbon atoms, further preferably 6 to 12 ring carbon atoms.

[0399] When Az has a substituted or unsubstituted aryl group as a substituent, the substituent is preferably a substituent selected from the group consisting of a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted phenanthryl group, a substituted or unsubstituted terphenyl group, and a substituted or unsubstituted fluorenyl group, more preferably, a substituent selected from the group consisting of a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, and a substituted or unsubstituted naphthyl group.

[0400] When Az has a substituted or unsubstituted heteroaryl group as a substituent, the substituent is preferably a substituent selected from the group consisting of a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted dibenzofuranyl group, and a substituted or unsubstituted dibenzothienyl group.

[0401] It is preferable that each R.sub.A4 is independently a hydrogen atom or a substituent, and R.sub.A4 serving as the substituent is a substituent selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms and a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms.

[0402] When R.sub.A4 serving as the substituent is a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, R.sub.A4 serving as the substituent is preferably a substituent selected from the group consisting of a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted phenanthryl group, a substituted or unsubstituted terphenyl group, and a substituted or unsubstituted fluorenyl group, more preferably a substituent selected from the group consisting of a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, and a substituted or unsubstituted naphthyl group.

[0403] When R.sub.A4 serving as the substituent is a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, R.sub.A4 serving as the substituent is preferably a substituent selected from the group consisting of a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted dibenzofuranyl group, and a substituted or unsubstituted dibenzothiophenyl group.

[0404] R.sub.45, R.sub.46, and R.sub.47 serving as the substituents are preferably each independently a substituent selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, and a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms.

[0405] In the compound M2 of the exemplary embodiment, when any one or more of R.sub.A3, R.sub.A4, R.sub.45 to R.sub.46, and R.sub.47 are hydrogen atoms, it is preferable that all the hydrogen atoms are protium atoms, at least one of the hydrogen atoms is a deuterium atom, or all the hydrogen atoms are deuterium.

[0406] In the compound M2 of the exemplary embodiment, when any one or more of R.sub.A3, R.sub.A4, R.sub.45 to R.sub.46, and R.sub.47 are substituents and the substituents have one or more hydrogen atoms, it is preferable that all the hydrogen atoms are protium atoms, at least one of the hydrogen atoms is a deuterium atom, or all the hydrogen atoms are deuterium atoms.

Manufacturing Method of Compound M2 According to Exemplary Embodiment

[0407] The compound M2 can be manufactured by a publicly known method.

[0408] For instance, the compound M2 can be manufactured by a method described in Examples below.

[0409] Further, the compound M2 can be manufactured by reactions described in later-described Examples and using known alternative reactions or raw materials tailored for the target compound.

[0410] Specific examples of the compound M2 of the exemplary embodiment include compounds below. It should however be noted that the invention is not limited to the specific examples of the compound.

[0411] In some of the specific examples of the compound M2, hydrogen atoms are omitted.

[0412] A specific example of the compound M2 in which hydrogen atoms are omitted will be described.

[0413] For instance, in the case where a specific example of the compound M2 is a compound represented by (M2-1) below, the compound is represented by a formula (M2-11) below when shown without omitting hydrogen atoms.

[0414] In the formula (M2-11) below, “H.sub.D” each represent a protium atom or a deuterium atom, and at least one of the plurality of “H.sub.D” is a deuterium atom.

##STR00126##

[0415] The following specific examples of the compound M2 are specific examples in which hydrogen atoms are omitted.

##STR00127## ##STR00128## ##STR00129## ##STR00130## ##STR00131## ##STR00132## ##STR00133## ##STR00134## ##STR00135## ##STR00136## ##STR00137## ##STR00138## ##STR00139## ##STR00140## ##STR00141## ##STR00142## ##STR00143## ##STR00144## ##STR00145## ##STR00146## ##STR00147## ##STR00148## ##STR00149## ##STR00150## ##STR00151## ##STR00152## ##STR00153## ##STR00154## ##STR00155## ##STR00156## ##STR00157## ##STR00158## ##STR00159## ##STR00160## ##STR00161## ##STR00162## ##STR00163##

[0416] The following specific examples of the compound M2 are specific examples in which hydrogen atoms are not omitted.

[0417] In the following specific examples, “D” represents a deuterium atom.

##STR00164## ##STR00165## ##STR00166## ##STR00167## ##STR00168## ##STR00169## ##STR00170## ##STR00171## ##STR00172## ##STR00173## ##STR00174## ##STR00175## ##STR00176## ##STR00177## ##STR00178## ##STR00179## ##STR00180##

Relationship Between Compound M3 and Compound M2 in Emitting Layer

[0418] In the organic EL device according to the exemplary embodiment, a singlet energy S.sub.1(M2) of the compound M2 and a singlet energy S.sub.1(M3) of the compound M3 satisfy a relationship of a numerical formula (Numerical Formula 1) below.

S.sub.1(M3)>S.sub.1(M2)  (Numerical Formula 1)

[0419] An energy gap T.sub.77K(M3) at 77K of the compound M3 is preferably larger than an energy gap T.sub.77K(M2) at 77K of the compound M2. In other words, a relationship of the following numerical formula (Numerical Formula 11) is preferably satisfied.

T.sub.77K(M3)>T.sub.77K(M2)  (Numerical Formula 11)

[0420] When the organic EL device according to the exemplary embodiment emits light, it is preferable that the compound M3 does not mainly emit light in the emitting layer.

Relationship Between Triplet Energy and Energy Gap at 77K

[0421] Here, a relationship between a triplet energy and an energy gap at 77K will be described. In the exemplary embodiment, the energy gap at 77K is different from a typical triplet energy in some aspects.

[0422] The triplet energy is measured as follows. Firstly, a solution in which a compound (measurement target) is dissolved in an appropriate solvent is encapsulated in a quartz glass tube to prepare a sample. A phosphorescent spectrum (ordinate axis: phosphorescent luminous intensity, abscissa axis: wavelength) of the sample is measured at a low temperature (77K). A tangent is drawn to the rise of the phosphorescent spectrum close to the short-wavelength region. The triplet energy is calculated by a predetermined conversion equation based on a wavelength value at an intersection of the tangent and the abscissa axis.

[0423] Here, a thermally activated delayed fluorescent compound M2 among the compounds of the exemplary embodiment is preferably a compound having a small ΔST. When ΔST is small, intersystem crossing and inverse intersystem crossing are likely to occur even at a low temperature (77K), so that the singlet state and the triplet state coexist. As a result, the spectrum to be measured in the same manner as the above includes emission from both the singlet state and the triplet state. Although it is difficult to distinguish the emission from the singlet state from the emission from the triplet state, the value of the triplet energy is basically considered dominant.

[0424] Accordingly, in the exemplary embodiment, the triplet energy is measured by the same method as a typical triplet energy T, but a value measured in the following manner is referred to as an energy gap T.sub.77K in order to differentiate the measured energy from the typical triplet energy in a strict meaning. The measurement target compound is dissolved in EPA (diethylether:isopentane:ethanol=5:5:2 in volume ratio) at a concentration of 10 μmol/L, and the obtained solution is encapsulated in a quartz cell to provide a measurement sample. A phosphorescent spectrum (ordinate axis: phosphorescent luminous intensity, abscissa axis: wavelength) of the sample is measured at a low temperature (77K). A tangent is drawn to the rise of the phosphorescent spectrum close to the short-wavelength region. An energy amount is calculated by a conversion equation (F1) below based on a wavelength value λ.sub.edge [nm] at an intersection of the tangent and the abscissa axis and is defined as an energy gap T.sub.77K at 77K.

T.sub.77K [eV]=1239.85/λ.sub.edge  Conversion Equation (F1):

[0425] The tangent to the rise of the phosphorescence spectrum close to the short-wavelength region is drawn as follows. While moving on a curve of the phosphorescence spectrum from the short-wavelength region to the local maximum value closest to the short-wavelength region among the local maximum values of the phosphorescence spectrum, a tangent is checked at each point on the curve toward the long-wavelength of the phosphorescence spectrum. An inclination of the tangent is increased along the rise of the curve (i.e., a value of the ordinate axis is increased). A tangent drawn at a point of the local maximum inclination (i.e., a tangent at an inflection point) is defined as the tangent to the rise of the phosphorescence spectrum close to the short-wavelength region.

[0426] A local maximum point where a peak intensity is 15% or less of the maximum peak intensity of the spectrum is not counted as the above-mentioned local maximum peak intensity closest to the short-wavelength region. The tangent drawn at a point that is closest to the local maximum peak intensity closest to the short-wavelength region and where the inclination of the curve is the local maximum is defined as a tangent to the rise of the phosphorescence spectrum close to the short-wavelength region.

[0427] For phosphorescence measurement, a spectrophotofluorometer body F-4500 (manufactured by Hitachi High-Technologies Corporation) is usable. Any device for phosphorescence measurement is usable. A combination of a cooling unit, a low temperature container, an excitation light source and a light-receiving unit may be used for phosphorescence measurement.

Singlet Energy S.SUB.1

[0428] A method of measuring a singlet energy S.sub.1 with use of a solution (occasionally referred to as a solution method) is exemplified by a method below.

[0429] A toluene solution of a measurement target compound at a concentration of 10 μmol/L is prepared and put in a quartz cell. An absorption spectrum (ordinate axis: absorption intensity, abscissa axis: wavelength) of the thus-obtained sample is measured at a normal temperature (300K). A tangent is drawn to the fall of the absorption spectrum close to the long-wavelength region, and a wavelength value λedge (nm) at an intersection of the tangent and the abscissa axis is assigned to a conversion equation (F2) below to calculate singlet energy.

S.sub.1 [eV]=1239.85/λedge  Conversion Equation (F2):

[0430] Any device for measuring absorption spectrum is usable. For instance, a spectrophotometer (U3310 manufactured by Hitachi, Ltd.) is usable.

[0431] The tangent to the fall of the absorption spectrum close to the long-wavelength region is drawn as follows. While moving on a curve of the absorption spectrum from the local maximum value closest to the long-wavelength region, among the local maximum values of the absorption spectrum, in a long-wavelength direction, a tangent at each point on the curve is checked. An inclination of the tangent is decreased and increased in a repeated manner as the curve falls (i.e., a value of the ordinate axis is decreased). A tangent drawn at a point where the inclination of the curve is the local minimum closest to the long-wavelength region (except when absorbance is 0.1 or less) is defined as the tangent to the fall of the absorption spectrum close to the long-wavelength region.

[0432] The local maximum absorbance of 0.2 or less is not counted as the above-mentioned local maximum absorbance closest to the long-wavelength region.

[0433] In the exemplary embodiment, a difference (S.sub.1−T77K) between the singlet energy S.sub.1 and the energy gap T.sub.77K at 77K is defined as ΔST.

[0434] In the exemplary embodiment, a difference ΔST(M3) between the singlet energy S.sub.1(M3) of the compound M3 and the energy gap T.sub.77K(M3) at 77K of the compound M3 preferably satisfies a relationship of a numerical formula (Numerical Formula 3) below.

ΔST(M3)=S.sub.1(M3)−T.sub.77K(M3)>0.35 eV  (Numerical Formula 3)

[0435] In the exemplary embodiment, a difference ΔST(M2) between the singlet energy S.sub.1(M2) of the compound M2 and the energy gap T.sub.77K(M2) at 77K of the compound M2 preferably satisfies a relationship of a numerical formula (Numerical Formula 1A) below, more preferably satisfies a relationship of a numerical formula (Numerical Formula 1B) below, further preferably satisfies a relationship of a numerical formula (Numerical Formula 1C) below, and further more preferably satisfies any relationship of a numerical formula (Numerical Formula 1 D) below.

ΔST(M2)=S.sub.1(M2)−T.sub.77K(M2)<0.3 eV  (Numerical Formula 1A)

ΔST(M2)=S.sub.1(M2)−T.sub.77K(M2)<0.2 eV  (Numerical Formula 1B)

ΔST(M2)=S.sub.1(M2)−T.sub.77K(M2)<0.1 eV  (Numerical Formula 1C)

ΔST(M2)=S.sub.1(M2)−T.sub.77K(M2)<0.01 eV  (Numerical Formula 1 D)

Film Thickness of Emitting Layer

[0436] A film thickness of the emitting layer of the organic EL device in the exemplary embodiment is preferably in a range from 5 nm to 50 nm, more preferably in a range from 7 nm to 50 nm, most preferably in a range from 10 nm to 50 nm. When the film thickness of the emitting layer is 5 nm or more, the formation of the emitting layer and the adjustment of the chromaticity are easy. When the film thickness of the emitting layer is 50 nm or less, an increase in the drive voltage is likely to be reducible.

Content Ratios of Compounds in Emitting Layer

[0437] Content ratios of the compounds M2 and M3 in the emitting layer preferably fall, for instance, within a range below.

[0438] The content ratio of the compound M2 is preferably in a range from 10 mass % to 80 mass %, more preferably in a range from 10 mass % to 60 mass %, further preferably in a range from 20 mass % to 60 mass %.

[0439] The content ratio of the compound M3 is preferably in a range from 20 mass % to 90 mass %, more preferably in a range from 40 mass % to 90 mass %, further preferably in a range from 40 mass % to 80 mass %.

[0440] It should be noted that the emitting layer of the exemplary embodiment may further contain material(s) other than the compounds M2 and M3.

[0441] The emitting layer may include a single type of the compound M2 or may include two or more types of the compound M2. The emitting layer may include a single type of the compound M3 or may include two or more types of the compound M3.

[0442] FIG. 4 shows a relationship in energy level and energy transfer between the compound M3 and the compound M2 in the emitting layer.

[0443] In FIG. 4, S0 represents a ground state. S1(M2) represents the lowest singlet state of the compound M2. T1(M2) represents the lowest triplet state of the compound M2. S1 (M3) represents the lowest singlet state of the compound M3. T1(M3) represents the lowest triplet state of the compound M3.

[0444] Dashed arrows in FIG. 4 show energy transfer between the excited states. An energy transfer occurs by Förster transfer from the lowest singlet state S1 of the compound M3 to the lowest singlet state S1 of the compound M2 or an energy transfer occurs by Dexter transfer from the lowest triplet state T1 of the compound M3 to the lowest triplet state T1 of the compound M2.

[0445] Further, when a material having a small ΔST(M2) is used as the compound M2, inverse intersystem crossing can be caused by a heat energy from the lowest triplet state T1 to the lowest singlet state S1 in the compound M2. Consequently, fluorescence from the lowest singlet state S1 of the compound M2 can be observed. It is inferred that the internal quantum efficiency can be theoretically raised up to 100% also by using delayed fluorescence by the TADF mechanism.

[0446] The organic EL device according to the exemplary embodiment contains a delayed fluorescent compound M2 and a compound M3 having the singlet energy larger than that of the compound M2 in the emitting layer.

[0447] According to the exemplary embodiment, an organic EL device emitting light with a long lifetime can be achieved.

[0448] The organic EL device according to the exemplary embodiment is applicable to an electronic device such as a display device and a light-emitting device.

[0449] An arrangement of an organic EL device will be further described below.

Substrate

[0450] The substrate is used as a support for the organic EL device. For instance, glass, quartz, plastics and the like are usable for the substrate. A flexible substrate is also usable. The flexible substrate is a bendable substrate, which is exemplified by a plastic substrate. Examples of the material for the plastic substrate include polycarbonate, polyarylate, polyethersulfone, polypropylene, polyester, polyvinyl fluoride, polyvinyl chloride, polyimide, and polyethylene naphthalate. Moreover, an inorganic vapor deposition film is also usable.

Anode

[0451] Metal, an alloy, an electrically conductive compound, a mixture thereof, or the like having a large work function (specifically, 4.0 eV or more) is preferably used as the anode formed on the substrate. Specific examples of the material include ITO (Indium Tin Oxide), indium oxide-tin oxide containing silicon or silicon oxide, indium oxide-zinc oxide, indium oxide containing tungsten oxide and zinc oxide, and graphene. In addition, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chrome (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), titanium (Ti), and nitrides of a metal material (e.g., titanium nitride) are usable.

[0452] The material is typically formed into a film by a sputtering method. For instance, the indium oxide-zinc oxide can be formed into a film by the sputtering method using a target in which zinc oxide in a range from 1 mass % to 10 mass % is added to indium oxide. Moreover, for instance, the indium oxide containing tungsten oxide and zinc oxide can be formed by the sputtering method using a target in which tungsten oxide in a range from 0.5 mass % to 5 mass % and zinc oxide in a range from 0.1 mass % to 1 mass % are added to indium oxide. In addition, the anode may be formed by a vacuum deposition method, a coating method, an inkjet method, a spin coating method or the like.

[0453] Among the organic layers formed on the anode, since the hole injecting layer adjacent to the anode is formed of a composite material into which holes are easily injectable irrespective of the work function of the anode, a material usable as an electrode material (e.g., metal, an alloy, an electroconductive compound, a mixture thereof, and the elements belonging to the group 1 or 2 of the periodic table) is also usable for the anode.

[0454] A material having a small work function such as elements belonging to Groups 1 and 2 in the periodic table of the elements, specifically, an alkali metal such as lithium (Li) and cesium (Cs), an alkaline earth metal such as magnesium (Mg), calcium (Ca) and strontium (Sr), alloys (e.g., MgAg and AlLi) including the alkali metal or the alkaline earth metal, a rare earth metal such as europium (Eu) and ytterbium (Yb), alloys including the rare earth metal are also usable for the anode. It should be noted that the vacuum deposition method and the sputtering method are usable for forming the anode using the alkali metal, alkaline earth metal and the alloy thereof. Further, when a silver paste is used for the anode, the coating method and the inkjet method are usable.

Cathode

[0455] It is preferable to use metal, an alloy, an electroconductive compound, a mixture thereof, or the like having a small work function (specifically, 3.8 eV or less) for the cathode. Examples of the material for the cathode include elements belonging to Groups 1 and 2 in the periodic table of the elements, specifically, the alkali metal such as lithium (Li) and cesium (Cs), the alkaline earth metal such as magnesium (Mg), calcium (Ca) and strontium (Sr), alloys (e.g., MgAg and AlLi) including the alkali metal or the alkaline earth metal, the rare earth metal such as europium (Eu) and ytterbium (Yb), and alloys including the rare earth metal.

[0456] It should be noted that the vacuum deposition method and the sputtering method are usable for forming the cathode using the alkali metal, alkaline earth metal and the alloy thereof. Further, when a silver paste is used for the cathode, the coating method and the inkjet method are usable.

[0457] By providing the electron injecting layer, various conductive materials such as Al, Ag, ITO, graphene, and indium oxide-tin oxide containing silicon or silicon oxide may be used for forming the cathode regardless of the work function. The conductive materials can be formed into a film using the sputtering method, inkjet method, spin coating method and the like.

Hole Injecting Layer

[0458] The hole injecting layer is a layer containing a substance exhibiting a high hole injectability. Examples of the substance exhibiting a high hole injectability include molybdenum oxide, titanium oxide, vanadium oxide, rhenium oxide, ruthenium oxide, chrome oxide, zirconium oxide, hafnium oxide, tantalum oxide, silver oxide, tungsten oxide, and manganese oxide.

[0459] In addition, the examples of the highly hole-injectable substance further include: an aromatic amine compound, which is a low-molecule organic compound, such as 4,4′,4″-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4′,4″-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA), 4,4′-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), 4,4′-bis(N-{4-[N′-(3-methylphenyl)-N′-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), 3-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), and 3-[N-(1-naphthyl)-N-(9-phenylcarbazole-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1); and dipyrazino[2,3-f:20,30-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HAT-CN).

[0460] In addition, a high polymer compound (e.g., oligomer, dendrimer and polymer) is usable as the substance exhibiting a high hole injectability. Examples of the high-molecule compound include poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N′-[4-(4-diphenylamino)phenyl]phenyl-N′-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), and poly[N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)benzidine] (abbreviation: Poly-TPD). Moreover, an acid-added high polymer compound such as poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonic acid) (PEDOT/PSS) and polyaniline/poly(styrene sulfonic acid) (PAni/PSS) are also usable. The hole injecting layer may be an inorganic layer or an organic layer.

Hole Transporting Layer

[0461] The hole transporting layer is a layer containing a highly hole-transporting substance. An aromatic amine compound, carbazole derivative, anthracene derivative and the like are usable for the hole transporting layer. Specific examples of a material for the hole transporting layer include an aromatic amine compound such as 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1′-biphenyl]-4,4′-diamine (abbreviation: TPD), 4-phenyl-4′-(9-phenylfluorene-9-yl)triphenylamine (abbreviation: BAFLP), 4,4′-bis[N-(9,9-dimethylfluorene-2-yl)-N-phenylamino]biphenyl (abbreviation: DFLDPBi), 4,4′,4″-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4′,4″-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA), and 4,4′-bis[N-(spiro-9,9′-bifluorene-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB). The above-described substances mostly have a hole mobility of 10.sup.−6 cm.sup.2/(V.Math.s) or more.

[0462] For the hole transporting layer, a carbazole derivative such as CBP, 9-[4-(N-carbazolyl)]phenyl-10-phenylanthracene (CzPA), and 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (PCzPA) and an anthracene derivative such as t-BuDNA, DNA, and DPAnth may be used. A high polymer compound such as poly(N-vinylcarbazole) (abbreviation: PVK) and poly(4-vinyltriphenylamine) (abbreviation: PVTPA) is also usable.

[0463] However, in addition to the above substances, any substance exhibiting a higher hole transportability than an electron transportability may be used. It should be noted that the layer containing the substance exhibiting a high hole transportability may be not only a single layer but also a laminate of two or more layers formed of the above substance(s).

[0464] When the hole transporting layer includes two or more layers, one of the layers with a larger energy gap is preferably provided closer to the emitting layer. An example of the material with a larger energy gap is HT-2 used in later-described Examples.

Electron Transporting Layer

[0465] The electron transporting layer is a layer containing a highly electron-transporting substance. For the electron transporting layer, 1) a metal complex such as an aluminum complex, beryllium complex, and zinc complex, 2) a hetero aromatic compound such as imidazole derivative, benzimidazole derivative, azine derivative, carbazole derivative, and phenanthroline derivative, and 3) a high polymer compound are usable. Specifically, as a low-molecule organic compound, a metal complex such as Alq, tris(4-methyl-8-quinolinato)aluminum (abbreviation: Almq.sub.3), bis(10-hydroxybenzo[h]quinolinato)beryllium (abbreviation: BeBq.sub.2), BAlq, Znq, ZnPBO and ZnBTZ is usable. In addition to the metal complex, a heteroaromatic compound such as 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(ptert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (abbreviation: OXD-7), 3-(4-tert-butylphenyl)-4-phenyl-5-(4-biphenylyl)-1,2,4-triazole (abbreviation: TAZ), 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenylyl)-1,2,4-triazole (abbreviation: p-EtTAZ), bathophenanthroline (abbreviation: BPhen), bathocuproine (abbreviation: BCP), and 4,4′-bis(5-methylbenzoxazole-2-yl)stilbene (abbreviation: BzOs) is usable. In the exemplary embodiment, a benzimidazole compound is preferably usable. The above-described substances mostly have an electron mobility of 10.sup.−6 cm.sup.2/Vs or more. It should be noted that any substance other than the above substance may be used for the electron transporting layer as long as the substance exhibits a higher electron transportability than the hole transportability. The electron transporting layer may be provided in the form of a single layer or a laminate of two or more layers of the above substance(s).

[0466] Further, a high polymer compound is usable for the electron transporting layer. For instance, poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviation: PF-Py), poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2′-bipyridine-6,6′-diyl)] (abbreviation: PF-BPy) and the like are usable.

Electron Injecting Layer

[0467] The electron injecting layer is a layer containing a highly electron-injectable substance. Examples of a material for the electron injecting layer include an alkali metal, alkaline earth metal and a compound thereof, examples of which include lithium (Li), cesium (Cs), calcium (Ca), lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF.sub.2), and lithium oxide (LiOx). In addition, the alkali metal, alkaline earth metal or the compound thereof may be added to the substance exhibiting the electron transportability in use. Specifically, for instance, magnesium (Mg) added to Alq may be used. In this case, the electrons can be more efficiently injected from the cathode.

[0468] Alternatively, the electron injecting layer may be provided by a composite material in a form of a mixture of the organic compound and the electron donor. Such a composite material exhibits excellent electron injectability and electron transportability since electrons are generated in the organic compound by the electron donor. In this case, the organic compound is preferably a material excellent in transporting the generated electrons. Specifically, the above examples (e.g., the metal complex and the hetero aromatic compound) of the substance forming the electron transporting layer are usable. As the electron donor, any substance exhibiting electron donating property to the organic compound is usable. Specifically, the electron donor is preferably alkali metal, alkaline earth metal and rare earth metal such as lithium, cesium, magnesium, calcium, erbium and ytterbium. The electron donor is also preferably alkali metal oxide and alkaline earth metal oxide such as lithium oxide, calcium oxide, and barium oxide. Moreover, a Lewis base such as magnesium oxide is usable. Further, the organic compound such as tetrathiafulvalene (abbreviation: TTF) is usable.

[0469] The electron injecting layer may be an inorganic layer or an organic layer. A layer formed of, for instance, lithium (Li), cesium (Cs), calcium (Ca), lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF.sub.2), or a lithium oxide (LiOx) corresponds to the inorganic layer. A layer formed of, for instance, Liq((8-quinolinolato)lithium) corresponds to the organic layer.

[0470] The organic EL device 1 of the exemplary embodiment includes, between the cathode 4 and the emitting layer 5, an electron transporting zone including one or more organic layers. In the case of FIG. 1, the electron transporting zone is formed of the electron transporting layer 8 and the electron injecting layer 9.

[0471] The electron transporting zone preferably includes a plurality of organic layers. The organic layers included in the electron transporting zone are preferably formed of two layers or more and four layers or less, and more preferably two layers or more and three layers or less.

[0472] The organic EL device 1 of the exemplary embodiment includes, between the anode 3 and the emitting layer 5, a hole transporting zone including one or more organic layers. In the case of FIG. 1, the hole transporting zone is formed of the hole injecting layer 6 and the hole transporting layer 7.

[0473] The hole transporting zone preferably includes a plurality of organic layers. The organic layers included in the hole transporting zone are preferably formed of two layers or more and four layers or less, and more preferably two layers or more and three layers or less.

[0474] At least one layer of the organic layers included in the electron transporting zone preferably contains a compound represented by a formula (E1) below.

[0475] The organic layers included in the electron transporting zone preferably include a first layer adjacent to the emitting layer, and the first layer preferably contains a compound represented by the formula (E1).

[0476] In the case of FIG. 1, the electron transporting layer 8 adjacent to the emitting layer 5 corresponds to the first layer.

[0477] A device arrangement that exhibits a practical performance included in a commercially available electronic device often includes a hole transporting zone and an electron transporting zone each of which is formed of a plurality of organic layers to improve, for instance, the power consumption. In a device arrangement that exhibits such a practical performance, the load on the TADF material and the load on the host material can be further reduced by considering the behavior of the charge injection into the emitting layer compared with an organic EL device having a simple device arrangement (in which, for instance, a hole transporting layer and an electron transporting layer are each formed of a single organic layer).

[0478] Presumably, for instance, when the electron transporting zone is configured to include at least two organic layers, and, of the organic layers included in the electron transporting zone, at least one layer (preferably, the first layer adjacent to the emitting layer) contains a compound represented by the formula (E1) below, both a deuterated TADF material and a deuterated host material can easily contribute to the improvement in the device lifetime. It is considered that, consequently, the device lifetime can be improved more significantly than that of the organic EL device of Patent Literature 1, which discloses a simple device arrangement.

##STR00181##

[0479] In the formula (E1),

[0480] X.sub.51 to X.sub.56 are each independently a nitrogen atom or CR.sub.50, or at least one pair of pairs of adjacent ones of R.sub.50 are mutually bonded to form a ring;

[0481] two or three of X.sub.51 to X.sub.56 are each a nitrogen atom;

[0482] each R.sub.50 is independently a hydrogen atom or a substituent;

[0483] each R.sub.50 serving as the substituent is independently a halogen atom, a cyano group, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 30 carbon atoms, a substituted or unsubstituted arylsilyl group having 6 to 60 ring carbon atoms, a substituted or unsubstituted arylphosphoryl group having 6 to 60 ring carbon atoms, a hydroxy group, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms, an amino group, a substituted or unsubstituted alkylamino group having 2 to 30 carbon atoms, a substituted or unsubstituted arylamino group having 6 to 60 ring carbon atoms, a thiol group, a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted germanium group, a substituted phosphine oxide group, a nitro group, a substituted or unsubstituted carbonyl group, or a substituted boryl group; and

[0484] a plurality of R.sub.50 are mutually the same or different.

[0485] The compound represented by the formula (E1) is preferably a compound represented by a formula (E2) below.

##STR00182##

[0486] In the formula (E2), X.sub.51, X.sub.53, and X.sub.55 each independently represent the same as X.sub.51, X.sub.53, and X.sub.55 in the formula (E1), R.sub.52, R.sub.54, and R.sub.56 each independently represent the same as R.sub.50 in CR.sub.50 in the formula (E1), and two or three of X.sub.51, X.sub.53, and X.sub.55 are nitrogen atoms.

[0487] In the formula (E2), it is preferable that R.sub.52 is a group represented by a formula (E21) below, and

[0488] R.sub.54 and R.sub.56 are each independently a group represented by the formula (E21) below, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms.

[Formula 192]

(HAr).sub.a-L.sub.3-*  (E21)

[0489] In the formula (E21), HAr is a group represented by a formula (E22) below, and a is an integer of 1 or more and 5 or less.

[0490] When a is 1, L.sub.3 is a single bond or a divalent linking group.

[0491] When a is 2 or more and 5 or less, L.sub.3 is a trivalent or higher and hexavalent or lower linking group, and HAr are the same or different.

[0492] In the formula (E21), L.sub.3 serving as the linking group is a group derived from a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a group derived from a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, or a group formed by bonding together two or three groups selected from the group consisting of groups derived from a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms and groups derived from a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, and

[0493] the groups bonded together are mutually the same or different.

[0494] * represents a bonding position to a benzene ring in the formula (E2).

##STR00183##

[0495] In the formula (E22), X.sub.11 to X.sub.18 are each independently a nitrogen atom, CR.sub.E3, or a carbon atom bonded to L.sub.3 through a single bond.

[0496] In the formula (E22), Y.sub.E1 is CR.sub.E1R.sub.E2, SiR.sub.E4R.sub.E5, an oxygen atom, a sulfur atom, a carbon atom bonded to R.sub.E6 and L.sub.3, or a silicon atom bonded to R.sub.E7 and L.sub.3,

[0497] one of carbon atoms in X.sub.11 to X.sub.18, a carbon atom in Y.sub.E1, and a silicon atom in Y.sub.E1 is bonded to L.sub.3, and

[0498] R.sub.E1 to R.sub.E7 are each independently a hydrogen atom, a halogen atom, a cyano group, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 30 carbon atoms, a substituted or unsubstituted arylsilyl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted aralkyl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms.

[0499] A plurality of R.sub.E3 are mutually the same or different.

[0500] Adjacent R.sub.E3 may be mutually bonded to form a ring.

[0501] In the formula (E22), X.sub.13 or X.sub.16 is preferably a carbon atom bonded to L.sub.3 through a single bond.

[0502] In the formula (E22), X.sub.11 or X.sub.18 is also preferably a carbon atom bonded to L.sub.3 through a single bond.

[0503] In the formula (E22), X.sub.12 or X.sub.17 is also preferably a carbon atom bonded to L.sub.3 through a single bond.

[0504] In the formula (E22), X.sub.14 or X.sub.15 is also preferably a carbon atom bonded to L.sub.3 through a single bond.

[0505] In the formula (E21), a is an integer of 1 or more and 5 or less, more preferably 1 or more and 3 or less, and further preferably 1 or 2.

[0506] In the formula (E21), when a is 1, L.sub.3 is a divalent linking group, and the formula (E21) is represented by a formula (E211) below.

[0507] In the formula (E21), when a is 2 or more and 5 or less, L.sub.3 is a trivalent or higher and hexavalent or lower linking group. When a is 2, L.sub.3 is a trivalent linking group, and the formula (E21) is represented by a formula (E212) below.

##STR00184##

[0508] In the formulae (E211) and (E212), L.sub.3 and HAr each independently represent the same as L.sub.3 and HAr in the formula (E21), and * represents a bonding position to a benzene ring in the formula (E2). A plurality of HAr are the same or different.

[0509] The compound represented by the formula (E1) is also preferably a compound represented by a formula (E11) or (E12) below.

##STR00185##

[0510] In the formula (E11), R.sub.51, R.sub.52, R.sub.54, and R.sub.56 each independently represent the same as R.sub.50 in CR.sub.50 in the formula (E1); and

[0511] in the formula (E12), R.sub.52, R.sub.54, and R.sub.56 each independently represent the same as R.sub.50 in CR.sub.50 in the formula (E1).

[0512] In the formula (E11), it is preferable that R.sub.51, R.sub.52, R.sub.54, and R.sub.56 are each independently a group represented by the formula (E21), a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms; and

[0513] one of R.sub.51, R.sub.52, R.sub.54, and R.sub.56 is a group represented by the formula (E21).

[0514] In the formula (E11), it is more preferable that R.sub.52 is a group represented by the formula (E21), and R.sub.51, R.sub.54, and R.sub.56 are each independently a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms.

[0515] In the formula (E12), it is preferable that R.sub.52, R.sub.54, and R.sub.56 are each independently a group represented by the formula (E21), a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms; and

[0516] one of R.sub.52, R.sub.54, and R.sub.56 is a group represented by the formula (E21).

[0517] In the formula (E12), it is more preferable that R.sub.52 is a group represented by the formula (E21), and R.sub.54 and R.sub.56 are each independently a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms.

[0518] In the formulae (E21), (E211), and (E212), L.sub.3 is preferably a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms or a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms.

[0519] In the formulae (E21), (E211), and (E212), L.sub.3 is preferably a divalent or trivalent residue derived from any of benzene, biphenyl, terphenyl, naphthalene, and phenanthrene.

[0520] In the formula (E21), it is more preferable that a is 1, and L.sub.3 is a divalent residue of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms or a divalent residue of a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms.

[0521] In the formula (E21), it is more preferable that a is 2, L.sub.3 is a linking group, and the linking group is a trivalent residue of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms or a trivalent residue of a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms.

[0522] In the formula (E22), Y.sub.E1 is preferably an oxygen atom.

[0523] In the formula (E22), Y.sub.E1 is also preferably a sulfur atom.

[0524] In the formula (E22), Y.sub.E1 is also preferably CR.sub.E1R.sub.E2.

[0525] In the formula (E22), it is preferable that Y.sub.E1 is an oxygen atom or a sulfur atom, X.sub.12 and X.sub.17 are CR.sub.E3, one of X.sub.11, X.sub.13 to X.sub.16, and X.sub.18 is a carbon atom bonded to L.sub.3 through a single bond, and the others are CR.sub.E3.

[0526] In the formula (E22), it is preferable that Y.sub.E1 is CR.sub.E1R.sub.E2, X.sub.11 and X.sub.18 are CR.sub.E3, one of X.sub.13 to X.sub.17 is a carbon atom bonded to L.sub.3 through a single bond, and the others are CR.sub.E3.

[0527] Specific examples of the compound represented by the formula (E1) are shown below. It should however be noted that the invention is not limited to the specific examples of the compound.

##STR00186## ##STR00187## ##STR00188## ##STR00189## ##STR00190##

Layer Formation Method

[0528] A method for forming each layer of the organic EL device in the exemplary embodiment is subject to no limitation except for the above particular description. However, known methods of dry film-forming such as vacuum deposition, sputtering, plasma or ion plating and wet film-forming such as spin coating, dipping, flow coating or ink-jet are applicable.

Film Thickness

[0529] A film thickness of each of the organic layers of the organic EL device in the exemplary embodiment is not limited unless otherwise specified in the above. In general, the thickness preferably ranges from several nanometers to 1 μm because excessively small film thickness is likely to cause defects (e.g. pin holes) and excessively large thickness leads to the necessity of applying high voltage and consequent reduction in efficiency.

Second Exemplary Embodiment

[0530] An arrangement of an organic EL device according to a second exemplary embodiment will be described below. In the description of the second exemplary embodiment, the same components as those in the first exemplary embodiment are denoted by the same reference signs and names to simplify or omit an explanation of the components. In the second exemplary embodiment, any materials and compounds that are not specified may be the same as those in the first exemplary embodiment.

[0531] The organic EL device according to the second exemplary embodiment is different from the organic EL device according to the first exemplary embodiment in that the emitting layer further includes a fluorescent compound M1. The second exemplary embodiment is the same as the first exemplary embodiment in other respects.

[0532] In other words, in the second exemplary embodiment, the emitting layer includes a compound M3 represented by the formula (3), a delayed fluorescent compound M2, and a fluorescent compound M1.

[0533] In this arrangement, the compound M1 is preferably a dopant material, the compound M2 is preferably a host material, and the compound M3 is preferably a host material. One of the compound M2 and the compound M3 may be referred to as a first host material, and the other may be referred to as a second host material.

Compound M1

[0534] The emitting layer of the exemplary embodiment includes the fluorescent compound M1.

[0535] The compound M1 of the exemplary embodiment is not a phosphorescent metal complex. The compound M1 of the exemplary embodiment is preferably not a heavy-metal complex. The compound M1 of the exemplary embodiment is preferably not a metal complex.

[0536] A fluorescent material is usable as the compound M1 of the exemplary embodiment. Specific examples of the fluorescent material include a bisarylaminonaphthalene derivative, aryl-substituted naphthalene derivative, bisarylaminoanthracene derivative, aryl-substituted anthracene derivative, bisarylaminopyrene derivative, aryl-substituted pyrene derivative, bisarylamino chrysene derivative, aryl-substituted chrysene derivative, bisarylaminofluoranthene derivative, aryl-substituted fluoranthene derivative, indenoperylene derivative, acenaphthofluoranthene derivative, compound including a boron atom, pyromethene boron complex compound, compound having a pyromethene skeleton, metal complex of the compound having a pyrromethene skeleton, diketopyrrolopyrrole derivative, perylene derivative, and naphthacene derivative.

[0537] The compound M1 of the exemplary embodiment is preferably a compound represented by a formula (10) below.

##STR00191##

[0538] In the formula (10):

[0539] X is a nitrogen atom, or a carbon atom bonded to Y;

[0540] Y is a hydrogen atom or a substituent;

[0541] R.sub.10 to R.sub.15 are each independently a hydrogen atom or a substituent, or at least one pair of a pair of R.sub.10 and R.sub.11, a pair of R.sub.11 and R.sub.12, a pair of R.sub.13 and R.sub.14, or a pair of R.sub.14 and R.sub.15 are mutually bonded to form a ring;

[0542] Y and R.sub.10 to R.sub.15 as a substituents are each independently selected from the group consisting of a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy halide group having 1 to 30 carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms, a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a halogen atom, a carboxy group, a substituted or unsubstituted ester group, a substituted or unsubstituted carbamoyl group, a substituted or unsubstituted amino group, a nitro group, a cyano group, a substituted or unsubstituted silyl group, and a substituted or unsubstituted siloxanyl group;

[0543] Z.sub.11 and Z.sub.12 are each independently a substituent, or Z.sub.11 and Z.sub.12 are mutually bonded to form a ring; and

[0544] Z.sub.11 and Z.sub.12 as the substituents are each independently selected from the group consisting of a halogen atom, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy halide group having 1 to 30 carbon atoms, and a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms.

[0545] In the formula (10), for instance, when a pair of R.sub.14 and R.sub.15 are mutually bonded to form a ring, the compound M1 is represented by a formula (11) below.

##STR00192##

[0546] In the formula (11): X, Y, R.sub.10 to R.sub.13, Z.sub.11 and Z.sub.12 respectively represent the same as X, Y, R.sub.10 to R.sub.13, Z.sub.11 and Z.sub.12 in the formula (10); R.sub.16 to R.sub.19 are each independently a hydrogen atom or a substituent; and R.sub.16 to R.sub.19 as the substituents each independently represent the same as R.sub.10 to R.sub.13 as the substituents.

[0547] In the formula (10), when Z.sub.11 and Z.sub.12 are mutually bonded to form a ring, the compound M1 is represented by, for instance, a formula (10A) or (10B) below. However, a structure of the compound M1 is not limited to structures below.

##STR00193##

[0548] In the formula (10A): X, Y and R.sub.10 to R.sub.15 respectively represent the same as X, Y and R.sub.10 to R.sub.15 in the formula (10); each R.sub.1A is independently a hydrogen atom or a substituent; R.sub.1A as the substituent represents the same as R.sub.10 to R.sub.15 as the substituents; and n3 is 4.

[0549] In the formula (10B): X, Y and R.sub.10 to R.sub.15 respectively represent the same as X, Y and R.sub.10 to R.sub.15 in the formula (10); each R.sub.1B is independently a hydrogen atom or a substituent; R.sub.1B as the substituent represents the same as R.sub.10 to R.sub.15 as the substituents; and n4 is 4.

[0550] It is preferable that at least one of Z.sub.11 or Z.sub.12 (preferably both of Z.sub.11 and Z.sub.12) is a group selected from the group consisting of a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy halide group having 1 to 30 carbon atoms, and a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms.

[0551] It is more preferable that at least one of Z.sub.11 or Z.sub.12 is a group selected from the group consisting of a fluorine-substituted alkoxy group having 1 to 30 carbon atoms, a fluorine-substituted aryloxy group having 6 to 30 ring carbon atoms, and an aryloxy group having 6 to 30 ring carbon atoms and substituted with a fluoroalkyl group having 1 to 30 carbon atoms.

[0552] Further preferably, at least one of Z.sub.11 or Z.sub.12 is a fluorine-substituted alkoxy group having 1 to 30 carbon atoms. Furthermore preferably, Z.sub.11 and Z.sub.12 are each a fluorine-substituted alkoxy group having 1 to 30 carbon atoms.

[0553] It is also preferable that Z.sub.11 and Z.sub.12 are the same.

[0554] Meanwhile, it is also preferable that at least one of Z.sub.11 or Z.sub.12 is a fluorine atom. It is also more preferable that both of Z.sub.11 and Z.sub.12 are fluorine atoms.

[0555] It is also preferable that at least one of Z.sub.11 or Z.sub.12 is a group represented by a formula (10a) below.

##STR00194##

[0556] In the formula (10a), A is a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 ring carbon atoms, L.sub.1 is a substituted or unsubstituted alkylene group having 1 to 6 carbon atoms or a substituted or unsubstituted arylene group having 6 to 12 ring carbon atoms, m is 0, 1, 2, 3, 4, 5, 6, or 7. When m is 2, 3, 4, 5, 6, or 7, a plurality of L.sub.12 are mutually the same or different. m is preferably 0, 1 or 2. When m is 0, A is directly bonded to O (oxygen atom).

[0557] In the formula (10), when Z.sub.11 and Z.sub.12 are each a group represented by the formula (10a), the compound M1 is a compound represented by a formula (12) below.

[0558] The compound M1 is also preferably a compound represented by the formula (12) below.

##STR00195##

[0559] In the formula (12), X, Y bonded to X being a carbon atom, and R.sub.10 to R.sub.15 respectively represent the same as X, Y and R.sub.10 to R.sub.15 in the formula (10). A.sub.11 and A.sub.12 represent the same as A in the formula (10a) and may be mutually the same or different. L.sub.11 and L.sub.12 represent the same as L.sub.1 in the formula (10a) and may be mutually the same or different. m1 and m2 are each independently 0, 1, 2, 3, 4, 5, 6 or 7, preferably 0, 1 or 2. When m1 is 2, 3, 4, 5, 6 or 7, a plurality of L.sub.11 are mutually the same or different. When m2 is 2, 3, 4, 5, 6 or 7, a plurality of L.sub.12 are mutually the same or different. When m1 is 0, A.sub.11 is directly bonded to O (oxygen atom). When m2 is 0, A.sub.12 is directly bonded to O (oxygen atom).

[0560] At least one of A or L.sub.1 in the formula (10a) is preferably substituted with a halogen atom, more preferably substituted with a fluorine atom.

[0561] A in the formula (10a) is more preferably a perfluoroalkyl group having 1 to 6 carbon atoms or a perfluoroaryl group having 6 to 12 ring carbon atoms, further preferably a perfluoroalkyl group having 1 to 6 carbon atoms.

[0562] L.sub.1 in the formula (10a) is more preferably a perfluoroalkylene group having 1 to 6 carbon atoms or a perfluoroarylene group having 6 to 12 ring carbon atoms, further preferably a perfluoroalkylene group having 1 to 6 carbon atoms.

[0563] In other words, the compound M1 is also preferably a compound represented by a formula (12a) below.

##STR00196##

[0564] In the formula (12a):

[0565] X represents the same as X in the formula (10);

[0566] Y bonded to X being a carbon atom represents the same as Y in the formula (10);

[0567] R.sub.10 to R.sub.15 each independently represent the same as R.sub.10 to R.sub.15 in the formula (10);

[0568] m3 is 0, 1, 2, 3 or 4;

[0569] m4 is 0, 1, 2, 3 or 4; and

[0570] m3 and m4 are mutually the same or different.

[0571] In the formulae (10), (11), (12) and (12a),

[0572] X is a carbon atom bonded to Y;

[0573] Y is a hydrogen atom or a substituent;

[0574] Y as the substituent is preferably a substituent selected from the group consisting of a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms and a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, more preferably a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms.

[0575] In the formulae (10), (11), (12) and (12a),

[0576] it is more preferable that:

[0577] X is a carbon atom bonded to Y;

[0578] Y is a hydrogen atom or a substituent;

[0579] Y as the substituent is a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms; and

[0580] when Y as the substituent is an aryl group having 6 to 30 ring carbon atoms having a substituent, the substituent is a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy halide group having 1 to 30 carbon atoms, or an aryl group having 6 to 30 ring carbon atoms and substituted by an alkyl group having 1 to 30 carbon atoms.

[0581] In the compound M1, Z.sub.11 and Z.sub.12 may be mutually bonded to form a ring. However, it is preferable that Z.sub.11 and Z.sub.12 are not mutually bonded to form no ring.

[0582] In the formulae (10), (12) and (12a), at least one of R.sub.10, R.sub.12, R.sub.13 or R.sub.15 is preferably a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms or a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms.

[0583] In the formulae (10), (12) and (12a), it is more preferable that R.sub.10, R.sub.12, R.sub.13 and R.sub.15 are each a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms or a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms. In this case, R.sub.11 and R.sub.14 are each preferably a hydrogen atom.

[0584] In the formulae (10), (12) and (12a), at least one of R.sub.10, R.sub.12, R.sub.13 or R.sub.15 is preferably a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms.

[0585] In the formulae (10), (12) and (12a), it is more preferable that R.sub.10, R.sub.12, R.sub.13 and R.sub.15 are each a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms. In this case, R.sub.11 and R.sub.14 are each preferably a hydrogen atom.

[0586] In the formulae (10), (12) and (12a),

[0587] it is more preferable that:

[0588] R.sub.10, R.sub.12, R.sub.13 and R.sub.15 are each independently a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms (preferably 1 to 6 carbon atoms), a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms (preferably 1 to 6 carbon atoms), or an aryl group having 6 to 30 ring carbon atoms (preferably 6 to 12 ring carbon atoms) and substituted with an alkyl group having 1 to 30 carbon atoms; and

[0589] R.sub.11 and R.sub.14 are hydrogen atoms.

[0590] In the formula (11), at least one of R.sub.10, R.sub.12 or R.sub.13 is preferably a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms or a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms.

[0591] In the formula (11), it is more preferable that R.sub.10, R.sub.12 and R.sub.13 are each a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms or a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms. In this case, R.sub.11 is preferably a hydrogen atom.

[0592] In the formula (11), at least one of R.sub.10, R.sub.12 or R.sub.13 is preferably a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms.

[0593] In the formula (11), it is more preferable that R.sub.10, R.sub.12 and R.sub.13 are each a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms. In this case, R.sub.11 is preferably a hydrogen atom.

[0594] In the formula (11),

[0595] it is more preferable that:

[0596] R.sub.10, R.sub.12 and R.sub.13 are each independently a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms (preferably 1 to 6 carbon atoms), a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms (preferably 1 to 6 carbon atoms), or an aryl group having 6 to 30 ring carbon atoms (preferably 6 to 12 ring carbon atoms) and substituted with an alkyl group having 1 to 30 carbon atoms, and

[0597] R.sub.11 is a hydrogen atom.

[0598] In the compound M1, examples of the fluorine-substituted alkoxy group include 2,2,2-trifluoroethoxy group, 2,2-difluoroethoxy group, 2,2,3,3,3-pentafluoro-1-propoxy group, 2,2,3,3-tetrafluoro-1-propoxy group, 1,1,1,3,3,3-hexafluoro-2-propoxy group, 2,2,3,3,4,4,4-heptafluoro-1-butyloxy group, 2,2,3,3,4,4-hexafluoro-1-butyloxy group, nonafluoro-tertiary-butyloxy group, 2,2,3,3,4,4,5,5,5-nonafluoropentanoxy group, 2,2,3,3,4,4,5,5,6,6,6-undecafluorohexanoxy group, 2,3-bis(trifluoromethyl)-2,3-butanedioxy group, 1,1,2,2-tetra(trifluoromethyl)ethylene glycoxy group, 4,4,5,5,6,6,6-heptafluorohexane-1,2-dioxy group, and 4,4,5,5,6,6,7,7,8,8,9,9,9-tridecafluorononane-1,2-dioxy group.

[0599] In the compound M1, examples of the fluorine-substituted aryloxy group or the aryloxy group substituted with a fluoroalkyl group include a pentafluorophenoxy group, 3,4,5-trifluorophenoxy group, 4-trifluoromethylphenoxy group, 3,5-bistrifluoromethylphenoxy group, 3-fluoro-4-trifluoromethylphenoxy group, 2,3,5,6-tetrafluoro-4-trifluoromethylphenoxy group, 4-fluorocatecholato group, 4-trifluoromethylcatecholato group, and 3,5-bistrifluoromethylcatecholato group.

[0600] When the compound M1 is a fluorescent compound, the compound M1 preferably emits light having a main peak wavelength in a range from 400 nm to 700 nm.

[0601] Herein, the main peak wavelength means a peak wavelength of an emission spectrum exhibiting a maximum luminous intensity among fluorescence spectra measured in a toluene solution in which a measurement target compound is dissolved at a concentration ranging from 10.sup.−6 mol/l to 10.sup.−5 mol/l. A spectrophotofluorometer (F-7000 manufactured by Hitachi High-Tech Science Corporation) is used as a measurement device.

[0602] The compound M1 preferably exhibits red or green light emission.

[0603] Herein, the red light emission refers to a light emission in which a main peak wavelength of fluorescence spectrum is in a range from 600 nm to 660 nm.

[0604] When the compound M1 is a red fluorescent compound, the main peak wavelength of the compound M1 is preferably in a range from 600 nm to 660 nm, more preferably in a range from 600 nm to 640 nm, further preferably in a range from 610 nm to 630 nm.

[0605] Herein, the green light emission refers to a light emission in which a main peak wavelength of fluorescence spectrum is in a range from 500 nm to 560 nm.

[0606] When the compound M1 is a green fluorescent compound, the main peak wavelength of the compound M1 is preferably in a range from 500 nm to 560 nm, more preferably in a range from 500 nm to 540 nm, further preferably in a range from 510 nm to 540 nm.

[0607] Herein, the blue light emission refers to a light emission in which a main peak wavelength of fluorescence spectrum is in a range from 430 nm to 480 nm.

[0608] When the compound M1 is a blue fluorescent compound, the main peak wavelength of the compound M1 is preferably in a range from 430 nm to 480 nm, more preferably in a range from 440 nm to 480 nm.

[0609] The main peak wavelength of light from an organic EL device is measured as follows.

[0610] Voltage is applied on the organic EL devices such that a current density becomes 10 mA/cm.sup.2, where spectral radiance spectrum is measured by a spectroradiometer CS-2000 (manufactured by Konica Minolta, Inc.).

[0611] A peak wavelength of an emission spectrum, at which the luminous intensity of the resultant spectral radiance spectrum is at the maximum, is measured and defined as the main peak wavelength (unit: nm).

Manufacturing Method of Compound M1

[0612] The compound M1 can be manufactured by a known method.

[0613] Specific examples of the compound M1 according to the exemplary embodiment are shown below. It should however be noted that the invention is not limited to the specific examples of the compound.

[0614] A coordinate bond between a boron atom and a nitrogen atom in a pyrromethene skeleton is shown by various means such as a solid line, a broken line, an arrow, and omission. Herein, the coordinate bond is shown by a solid line or a broken line, or the description of the coordinate bond is omitted.

##STR00197## ##STR00198## ##STR00199## ##STR00200## ##STR00201## ##STR00202## ##STR00203## ##STR00204## ##STR00205## ##STR00206## ##STR00207## ##STR00208## ##STR00209## ##STR00210## ##STR00211##

Relationship Between Compound M3, Compound M2 and Compound M1 in Emitting Layer

[0615] In the organic EL device according to the exemplary embodiment, the singlet energy S.sub.1(M2) of the compound M2 and a singlet energy S.sub.1(M1) of the compound M1 preferably satisfy a relationship of a numerical formula (Numerical Formula 2) below.

S.sub.1(M2)>S.sub.1(M1)  (Numerical Formula 2)

[0616] The singlet energy S.sub.1(M3) of the compound M3 is preferably larger than the singlet energy S.sub.1(M1) of the compound M1.

S.sub.1(M3)>S.sub.1(M1)  (Numerical Formula 2A)

[0617] The singlet energy S.sub.1(M3) of the compound M3, the singlet energy S.sub.1(M2) of the compound M2, and the singlet energy S.sub.1(M1) of the compound M1 preferably satisfy a relationship of a numerical formula (Numerical Formula 2B) below.

S.sub.1(M3)>S.sub.1(M2)>S.sub.1(M1)  (Numerical Formula 2B)

[0618] When the organic EL device according to the exemplary embodiment emits light, it is preferable that the fluorescent compound M1 in the emitting layer mainly emits light.

[0619] The organic EL device according to the exemplary embodiment preferably emits red light or green light.

Content Ratios of Compounds in Emitting Layer

[0620] Content ratios of the compounds M3, M2 and M1 in the emitting layer are preferably fall within, for instance, the following range.

[0621] The content ratio of the compound M3 is preferably in a range from 10 mass % to 80 mass %.

[0622] The content ratio of the compound M2 is preferably in a range from 10 mass % to 80 mass %, more preferably in a range from 10 mass % to 60 mass %, further preferably in a range from 20 mass % to 60 mass %.

[0623] The content ratio of the compound M1 is preferably in a range from 0.01 mass % to 10 mass %, more preferably in a range from 0.01 mass % to 5 mass %, further preferably in a range from 0.01 mass % to 1 mass %.

[0624] An upper limit of the total of the respective content ratios of the compounds M3, M2 and M1 in the emitting layer is 100 mass %. It should be noted that the emitting layer of the exemplary embodiment may further contain material(s) other than the compounds M3, M2 and M1.

[0625] The emitting layer may include a single type of the compound M3 or may include two or more types of the compound M3. The emitting layer may include a single type of the compound M2 or may include two or more types of the compound M2. The emitting layer may include a single type of the compound M1 or may include two or more types of the compound M1.

[0626] FIG. 5 shows an example of a relationship between energy levels of the compounds M3, M2 and M1 in the emitting layer. In FIG. 5, S0 represents a ground state. S1(M1) represents the lowest singlet state of the compound M1. T1 (M1) represents the lowest triplet state of the compound M1. S1 (M2) represents the lowest singlet state of the compound M2. T1 (M2) represents the lowest triplet state of the compound M1. S1 (M3) represents the lowest singlet state of the compound M3. T1(M3) represents the lowest triplet state of the compound M3. A dashed arrow directed from S1(M2) to S1(M1) in FIG. 5 represents Förster energy transfer from the lowest singlet state of the compound M2 to the lowest singlet state of the compound M1.

[0627] As shown in FIG. 5, when a compound having a small ΔST(M2) is used as the compound M2, inverse intersystem crossing from the lowest triplet state T1(M2) to the lowest singlet state S1(M2) can be caused by a heat energy. Subsequently, Förster energy transfer from the lowest singlet state S1(M2) of the compound M2 to the compound M1 occurs to generate the lowest singlet state S1(M1). Consequently, fluorescence from the lowest singlet state S1(M1) of the compound M1 can be observed. It is inferred that the internal quantum efficiency can be theoretically raised up to 100% also by using delayed fluorescence by the TADF mechanism.

[0628] The organic EL device according to the second exemplary embodiment contains the delayed fluorescent compound M2, the compound M3 having the singlet energy larger than that of the compound M2, and the compound M1 having the singlet energy smaller than that of the delayed fluorescent compound M2 in the emitting layer.

[0629] According to the second exemplary embodiment, an organic EL device that emits light with a long lifetime can be achieved.

[0630] The organic EL device according to the second exemplary embodiment is applicable to an electronic device such as a display device and a light-emitting device.

Third Exemplary Embodiment

Electronic Device

[0631] An electronic device according to a third exemplary embodiment is installed with any one of the organic EL devices according to the above exemplary embodiments. Examples of the electronic device include a display device and a light-emitting device. Examples of the display device include a display component (e.g., an organic EL panel module), TV, mobile phone, tablet and personal computer. Examples of the light-emitting device include an illuminator and a vehicle light.

Fourth Exemplary Embodiment

Organic-EL-Device Material

[0632] An organic-EL-device material according to a fourth exemplary embodiment contains a delayed fluorescent compound M2 having at least one deuterium atom and a compound M3 having at least one deuterium atom, in which a singlet energy S.sub.1(M2) of the compound M2 and a singlet energy S.sub.1(M3) of the compound M3 satisfy the relationship of the numerical formula (Numerical Formula 1).

[0633] However, preferably, the organic-EL-device material according to the fourth exemplary embodiment does not contain a compound having a partial structure represented by the formula (1C) or (2C).

[0634] According to the organic-EL-device material according to the fourth exemplary embodiment, the lifetime of an organic EL device can be extended.

[0635] The organic-EL-device material according to the fourth exemplary embodiment may further contain an additional compound. When the organic-EL-device material according to the fourth exemplary embodiment further contains the additional compound, the additional compound may be solid or liquid.

Modification of Embodiment(s)

[0636] The scope of the invention is not limited to the above-described exemplary embodiments but includes any modification and improvement as long as such modification and improvement are compatible with the invention.

[0637] For instance, the emitting layer is not limited to a single layer, but may be provided by laminating a plurality of emitting layers. When the organic EL device has a plurality of emitting layers, it is only required that at least one of the emitting layers satisfies the conditions described in the above exemplary embodiments. For instance, the rest of the emitting layers may be a fluorescent emitting layer or a phosphorescent emitting layer with use of emission caused by electron transfer from the triplet excited state directly to the ground state.

[0638] When the organic EL device includes a plurality of emitting layers, these emitting layers may be mutually adjacently provided, or may form a so-called tandem organic EL device, in which a plurality of emitting units are layered via an intermediate layer.

[0639] For instance, a blocking layer may be provided adjacent to at least one of a side of the emitting layer close to the anode or a side of the emitting layer close to the cathode. The blocking layer is preferably provided in contact with the emitting layer to block at least any of holes, electrons, or excitons.

[0640] For instance, when the blocking layer is provided in contact with the side of the emitting layer close to the cathode, the blocking layer permits transport of electrons and blocks holes from reaching a layer provided closer to the cathode (e.g., the electron transporting layer) beyond the blocking layer. When the organic EL device includes the electron transporting layer, the blocking layer is preferably interposed between the emitting layer and the electron transporting layer.

[0641] When the blocking layer is provided in contact with the side of the emitting layer close to the anode, the blocking layer permits transport of holes and blocks electrons from reaching a layer provided closer to the anode (e.g., the hole transporting layer) beyond the blocking layer. When the organic EL device includes the hole transporting layer, the blocking layer is preferably interposed between the emitting layer and the hole transporting layer.

[0642] Alternatively, the blocking layer may be provided adjacent to the emitting layer so that excitation energy does not leak out from the emitting layer toward neighboring layer(s). The blocking layer blocks excitons generated in the emitting layer from being transferred to a layer(s) (e.g., the electron transporting layer and the hole transporting layer) closer to the electrode(s) beyond the blocking layer.

[0643] The emitting layer is preferably joined to the blocking layer.

[0644] Specific structure, shape and the like of the components in the invention may be designed in any manner as long as an object of the invention can be achieved.

Other Explanations

[0645] Herein, numerical ranges represented by “x to y” represents a range whose lower limit is the value (x) recited before “to” and whose upper limit is the value (y) recited after “to.”

[0646] Rx and Ry are mutually bonded to form a ring, which means herein, for instance, that Rx and Ry contain a carbon atom, a nitrogen atom, an oxygen atom, a sulfur atom or a silicon atom, the atom (a carbon atom, a nitrogen atom, an oxygen atom, a sulfur atom or a silicon atom) contained in Rx and the atom (a carbon atom, a nitrogen atom, an oxygen atom, a sulfur atom or a silicon atom) contained in Ry are mutually bonded via a single bond, a double bond, a triple bond or a divalent linking group to form a ring having 5 or more ring atoms (specifically, a heterocyclic ring or an aromatic hydrocarbon ring). x represents a number, a character or a combination of a number and a character. y represents a number, a character or a combination of a number and a character.

[0647] The divalent linking group is not particularly limited and is exemplified by —O—, —CO—, —CO.sub.2—, —S—, —SO—, —SO.sub.2—, —NH—, —NRa—, and a group obtained by combining two or more linking groups of these linking group.

[0648] Specific examples of the heterocyclic ring include a cyclic structure (heterocyclic ring) obtained by removing a bond from a “heteroaryl group Sub.sub.2” exemplarily shown in the later-described “Description of Each Substituent in Formula.” The heterocyclic ring may have a substituent.

[0649] Specific examples of the aromatic hydrocarbon ring include cyclic structures (aromatic hydrocarbon rings) obtained by removing a bond from an “aryl group Sub.sub.1” exemplarily shown in the later-described “Description of Each Substituent in Formula.” The aromatic hydrocarbon ring may have a substituent.

[0650] Examples of Ra include a substituted or unsubstituted alkyl group Sub.sub.3 having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group Sub.sub.1 having 6 to 40 ring carbon atoms, and a substituted or unsubstituted heteroaryl group Sub.sub.2 having 5 to 30 ring atoms, which are exemplarily shown in the later-described “Description of Each Substituent in Formula.”

[0651] Rx and Ry are mutually bonded to form a ring, which means, for instance, that: an atom contained in Rx.sub.1 and an atom contained in Ry.sub.1 in a molecular structure represented by a formula (E1) below form a ring (cyclic structure) E represented by a formula (E2); an atom contained in Rx.sub.1 and an atom contained in Ry.sub.1 in a molecular structure represented by a formula (F1) below form a ring (cyclic structure) F represented by a formula (F2); an atom contained in Rx.sub.1 and an atom contained in Ry.sub.1 in a molecular structure represented by a formula (G1) below form a ring (cyclic structure) G represented by a formula (G2); an atom contained in Rx.sub.1 and an atom contained in Ry.sub.1 in a molecular structure represented by a formula (H1) below form a ring (cyclic structure) H represented by a formula (H2); and an atom contained in Rx.sub.1 and an atom contained in Ry.sub.1 in a molecular structure represented by a formula (I1) below form a ring (cyclic structure) I represented by a formula (I2).

[0652] In the formulae (E1) to (I1), * each independently represents a bonding position to another atom in a molecule. Two * in the formula (E1) correspond one-to-one to two * in the formula (E2). Two * in the formula (F1) correspond one-to-one to two * in the formula (F2). Two * in the formula (G1) correspond one-to-one to two * in the formula (G2). Two * in the formula (H1) correspond one-to-one to two * in the formula (H2). Two * in the formula (I1) correspond one-to-one to two * in the formula (I2).

##STR00212##

[0653] In the molecular structures represented by the respective formulae (E2) to (I2), E to I each represent a cyclic structure (the ring having 5 or more ring atoms). In the formulae (E2) to (I2), * each independently represents a bonding position to another atom in a molecule. Two * in the formula (E2) correspond one-to-one to two * in the formula (E1). Similarly, two * in each of the formulae (F2) to (I2) correspond one-to-one to two * in in each of the formulae (F1) to (I1).

[0654] For instance, in the formula (E1), when Rx.sub.1 and Ry.sub.1 are mutually bonded to form the ring E in the formula (E2) and the ring E is an unsubstituted benzene ring, the molecular structure represented by the formula (E1) is a molecular structure represented by a formula (E3) below. Herein, two * in the formula (E3) correspond one-to-one to two * in each of the formulae (E2) and (E1).

[0655] For instance, in the formula (E1), when Rx.sub.1 and Ry.sub.1 are mutually bonded to form the ring E in the formula (E2) and the ring E is an unsubstituted pyrrole ring, the molecular structure represented by the formula (E1) is a molecular structure represented by a formula (E4) below. Herein, two * in the formula (E4) correspond one-to-one to two * in each of the formulae (E2) and (E1). In the formulae (E3) and (E4), * each independently represents a bonding position to another atom in a molecule.

##STR00213##

[0656] Herein, the ring carbon atoms refer to the number of carbon atoms among atoms forming a ring of a compound (e.g., a monocyclic compound, fused-ring compound, crosslinking compound, carbon ring compound, and heterocyclic compound) in which the atoms are bonded to each other to form the ring. When the ring is substituted by a substituent(s), carbon atom(s) contained in the substituent(s) is not counted in the ring carbon atoms. Unless specifically described, the same applies to the “ring carbon atoms” described later. For instance, a benzene ring has 6 ring carbon atoms, a naphthalene ring has 10 ring carbon atoms, a pyridinyl group has 5 ring carbon atoms, and a furanyl group has 4 ring carbon atoms. When a benzene ring and/or a naphthalene ring is substituted by a substituent (e.g., an alkyl group), the number of carbon atoms of the alkyl group is not counted in the number of the ring carbon atoms. When a fluorene ring is substituted by a substituent (e.g., a fluorene ring) (i.e., a spirofluorene ring is included), the number of carbon atoms of the fluorene ring as the substituent is not counted in the number of the ring carbon atoms of the fluorene ring.

[0657] Herein, the ring atoms refer to the number of atoms forming a ring of a compound (e.g., a monocyclic compound, fused-ring compound, crosslinking compound, carbon ring compound, and heterocyclic compound) in which the atoms are bonded to each other to form the ring (e.g., monocyclic ring, fused ring, ring assembly). Atom(s) not forming a ring and atom(s) included in a substituent when the ring is substituted by the substituent are not counted in the number of the ring atoms. Unless specifically described, the same applies to the “ring atoms” described later. For instance, a pyridine ring has six ring atoms, a quinazoline ring has ten ring atoms, and a furan ring has five ring atoms. A hydrogen atom(s) and/or an atom(s) of a substituent which are bonded to carbon atoms of a pyridine ring and/or quinazoline ring are not counted in the ring atoms. When a fluorene ring is substituted by a substituent (e.g., a fluorene ring) (i.e., a spirofluorene ring is included), the number of atoms of the fluorene ring as the substituent is not counted in the number of the ring atoms of the fluorene ring.

Description of Each Substituent in Formulae Herein

[0658] The aryl group (occasionally referred to as an aromatic hydrocarbon group) herein is exemplified by an aryl group Sub.sub.1. The aryl group Sub.sub.1 preferably has 6 to 30 ring carbon atoms, more preferably 6 to 20 ring carbon atoms, further preferably 6 to 14 ring carbon atoms, still further preferably 6 to 12 ring carbon atoms.

[0659] The aryl group Sub.sub.1 herein is at least one group selected from the group consisting of a phenyl group, biphenyl group, terphenyl group, naphthyl group, anthryl group, phenanthryl group, fluorenyl group, pyrenyl group, chrysenyl group, fluoranthenyl group, benz[a]anthryl group, benzo[c]phenanthryl group, triphenylenyl group, benzo[k]fluoranthenyl group, benzo[g]chrysenyl group, benzo[b]triphenylenyl group, picenyl group, and perylenyl group.

[0660] Among the aryl group Sub.sub.1, a phenyl group, biphenyl group, naphthyl group, phenanthryl group, terphenyl group and fluorenyl group are preferable. A carbon atom in a position 9 of each of 1-fluorenyl group, 2-fluorenyl group, 3-fluorenyl group and 4-fluorenyl group is preferably substituted by a substituted or unsubstituted alkyl group Sub.sub.3 or a substituted or unsubstituted aryl group Sub.sub.1 described later herein.

[0661] The heteroaryl group (occasionally referred to as a heterocyclic group, heteroaromatic cyclic group or aromatic heterocyclic group) herein is exemplified by a heterocyclic group Sub.sub.2. The heterocyclic group Sub.sub.2 is a group containing, as a hetero atom(s), at least one atom selected from the group consisting of nitrogen, sulfur, oxygen, silicon, selenium atom and germanium atom. The heterocyclic group Sub.sub.2 preferably contains, as a hetero atom(s), at least one atom selected from the group consisting of nitrogen, sulfur and oxygen. The heterocyclic group Sub.sub.2 preferably has 5 to 30 ring atoms, more preferably 5 to 20 ring atoms, further preferably 5 to 14 ring atoms.

[0662] The heterocyclic group Sub.sub.2 herein are, for instance, at least one group selected from the group consisting of a pyridyl group, pyrimidinyl group, pyrazinyl group, pyridazinyl group, triazinyl group, quinolyl group, isoquinolinyl group, naphthyridinyl group, phthalazinyl group, quinoxalinyl group, quinazolinyl group, phenanthridinyl group, acridinyl group, phenanthrolinyl group, pyrrolyl group, imidazolyl group, pyrazolyl group, triazolyl group, tetrazolyl group, indolyl group, benzimidazolyl group, indazolyl group, imidazopyridinyl group, benzotriazolyl group, carbazolyl group, furyl group, thienyl group, oxazolyl group, thiazolyl group, isoxazolyl group, isothiazolyl group, oxadiazolyl group, thiadiazolyl group, benzofuranyl group, benzothienyl group, benzoxazolyl group, benzothiazolyl group, benzisoxazolyl group, benzisothiazolyl group, benzoxadiazolyl group, benzothiadiazolyl group, dibenzofuranyl group, dibenzathienyl group, piperidinyl group, pyrrolidinyl group, piperazinyl group, morpholyl group, phenazinyl group, phenothiazinyl group, and phenoxazinyl group.

[0663] Among the above heterocyclic group Sub.sub.2, a 1-dibenzofuranyl group, 2-dibenzofuranyl group, 3-dibenzofuranyl group, 4-dibenzofuranyl group, 1-dibenzothienyl group, 2-dibenzothienyl group, 3-dibenzothienyl group, 4-dibenzothienyl group, 1-carbazolyl group, 2-carbazolyl group, 3-carbazolyl group, 4-carbazolyl group, and 9-carbazolyl group are further more preferable. A nitrogen atom in position 9 of 1-carbazolyl group, 2-carbazolyl group, 3-carbazolyl group and 4-carbazolyl group is preferably substituted by the substituted or unsubstituted aryl group Sub.sub.1 or the substituted or unsubstituted heterocyclic group Sub.sub.2 described herein.

[0664] Herein, the heterocyclic group Sub.sub.2 may be a group derived from any one of partial structures represented by formulae (XY-1) to (XY-18) below.

##STR00214## ##STR00215## ##STR00216##

[0665] in the formulae (XY-1) to (XY-18), X.sub.A and Y.sub.A each independently represent a hetero atom, and preferably represent an oxygen atom, sulfur atom, selenium atom, silicon atom or germanium atom. Each of the partial structures represented by the formulae (XY-1) to (XY-18) has a bond at any position to provide a heterocyclic group. The heterocyclic group may be substituted.

[0666] Herein, the heterocyclic group Sub.sub.2 may be a group represented by one of formulae (X-19) to (XY-22) below. Moreover, the position of the bond may be changed as needed.

##STR00217##

[0667] The alkyl group herein may be any one of a linear alkyl group, branched alkyl group and cyclic alkyl group.

[0668] The alkyl group herein is exemplified by an alkyl group Sub.sub.3.

[0669] The linear alkyl group herein is exemplified by a linear alkyl group Sub.sub.31.

[0670] The branched alkyl group herein is exemplified by a branched alkyl group Sub.sub.32.

[0671] The cyclic alkyl group herein is exemplified by a cyclic alkyl group Sub.sub.33 (also referred to as a cycloalkyl group Sub.sub.33).

[0672] For instance, the alkyl group Sub.sub.3 is at least one group selected from the group consisting of the linear alkyl group Sub.sub.31, branched alkyl group Sub.sub.32, and cyclic alkyl group Sub.sub.33.

[0673] Herein, the linear alkyl group Sub.sub.31 or branched alkyl group Sub.sub.32 preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, further preferably 1 to 10 carbon atoms, further more preferably 1 to 6 carbon atoms.

[0674] The cycloalkyl group Sub.sub.33 herein preferably has 3 to 30 ring carbon atoms, more preferably 3 to 20 ring carbon atoms, further preferably 3 to 10 ring carbon atoms, still further preferably 5 to 5 ring carbon atoms.

[0675] Herein, the linear alkyl group Sub.sub.31 or branched alkyl group Sub.sub.32 is exemplified by at least one group selected from the group consisting of a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group, n-pentyl group, n-hexyl group, n heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, neopentyl group, amyl group, isoamyl group, 1-methylpentyl group, 2-methylpentyl group, 1-pentylhexyl group, 1-butylpentyl group, 1-heptyloctyl group, and 3-methylpentyl group.

[0676] The linear alkyl group Sub.sub.31 or branched alkyl group Sub.sub.32 is further more preferably a methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group, n-pentyl group, n-hexyl group, amyl group, isoamyl group and neopentyl group.

[0677] The cycloalkyl group Sub.sub.33 herein is exemplified by at least one group selected from the group consisting of a cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, 4-metylcyclohexyl group, adamantyl group and norbornyl group. Among the cycloalkyl group Sub.sub.33, a cyclopentyl group and a cyclohexyl group are still further preferable.

[0678] Herein, an alkyl halide group is exemplified by an alkyl halide group Sub.sub.4. The alkyl halide group Sub.sub.4 is provided by substituting the alkyl group Sub.sub.3 with at least one halogen atom, preferably at least one fluorine atom.

[0679] Herein, the alkyl halide group Sub.sub.4 is exemplified by at least one group selected from the group consisting of a fluoromethyl group, difluoromethyl group, trifluoromethyl group, fluoroethyl group, trifluoromethylmethyl group, trifluoroethyl group, and pentafluoroethyl group.

[0680] Herein, a substituted silyl group is exemplified by a substituted silyl group Sub.sub.5. The substituted silyl group Sub.sub.5 is exemplified by at least one group selected from the group consisting of an alkylsilyl group Sub.sub.51 and an arylsilyl group Sub.sub.52.

[0681] Herein, the alkylsilyl group Sub.sub.51 is exemplified by a trialkylsilyl group Sub.sub.511 having the above-described alkyl group Sub.sub.3.

[0682] The trialkylsilyl group Sub.sub.511 is exemplified by at least one group selected from the group consisting of a trimethylsilyl group, triethylsilyl group, tri-n-butylsilyl group, tri-n-octylsilyl group, triisobutylsilyl group, dimethylethylsilyl group, dimethylisopropylsilyl group, dimethyl-n-propylsilyl group, dimethyl-n-butylsilyl group, dimethyl-t-butylsilyl group, diethylisopropylsilyl group, vinyl dimethylsilyl group, propyldimethylsilyl group, and triisopropylsilyl group. Three alkyl groups Sub.sub.3 in the trialkylsilyl group Sub.sub.511 may be mutually the same or different.

[0683] Herein, the arylsilyl group Sub.sub.52 is exemplified by at least one group selected from the group consisting of a dialkylarylsilyl group Sub.sub.521, alkyldiarylsilyl group Sub.sub.522 and triarylsilyl group Sub.sub.523.

[0684] The dialkylarylsilyl group Sub.sub.521 is exemplified by a dialkylarylsilyl group including two alkyl groups Sub.sub.3 and one aryl group Sub.sub.1. The dialkylarylsilyl group Sub.sub.521 preferably has 8 to 30 carbon atoms.

[0685] The alkyldiarylsilyl group Sub.sub.522 is exemplified by an alkyldiarylsilyl group including one alkyl group Sub.sub.3 and two aryl groups Sub.sub.1. The alkyldiarylsilyl group Sub.sub.522 preferably has 13 to 30 carbon atoms.

[0686] The triarylsilyl group Sub.sub.523 is exemplified by a triarylsilyl group including three aryl groups Sub.sub.1. The triarylsilyl group Sub.sub.523 preferably has 18 to 30 carbon atoms.

[0687] Herein, a substituted or unsubstituted alkyl sulfonyl group is exemplified by an alkyl sulfonyl group Sub.sub.6. The alkyl sulfonyl group Sub.sub.6 is represented by —SO.sub.2Rw. R.sub.w in —SO.sub.2R.sub.w represents a substituted or unsubstituted alkyl group Sub.sub.3 described above.

[0688] Herein, an aralkyl group (occasionally referred to as an arylalkyl group) is exemplified by an aralkyl group Sub.sub.7. An aryl group in the aralkyl group Sub.sub.7 includes, for instance, at least one of the above-described aryl group Sub.sub.1 or the above-described heteroaryl group Sub.sub.2.

[0689] The aralkyl group Sub.sub.7 herein is preferably a group having the aryl group Sub.sub.1 and is represented by —Z.sub.3-Z.sub.4. Z.sub.3 is exemplified by an alkylene group corresponding to the above alkyl group Sub.sub.3. Z.sub.4 is exemplified by the above aryl group Sub.sub.1. In this aralkyl group Sub.sub.7, an aryl moiety has 6 to 30 carbon atoms (preferably 6 to 20 carbon atoms, more preferably 6 to 12 carbon atoms) and an alkyl moiety has 1 to 30 carbon atoms (preferably 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, further preferably 1 to 6 carbon atoms). The aralkyl group Sub.sub.7 is exemplified by at least one group selected from the group consisting of a benzyl group, 2-phenylpropane-2-yl group, 1-phenylethyl group, 2-phenylethyl group, 1-phenylisopropyl group, 2-phenylisopropyl group, phenyl-t-butyl group, α-naphthylmethyl group, 1-α-naphthylethyl group, 2-α-naphthylethyl group, 1-α-naphthylisopropyl group, 2-α-naphthylisopropyl group, β-naphthylmethyl group, 1-β-naphthylethyl group, 2-β-naphthylethyl group, 1-β-naphthylisopropyl group, and 2-β-naphthylisopropyl group.

[0690] The alkoxy group herein is exemplified by an alkoxy group Sub.sub.8. The alkoxy group Sub.sub.8 is represented by —OZ.sub.1. Z.sub.1 is exemplified by the above alkyl group Sub.sub.3. The alkoxy group Sub.sub.8 preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms. The alkoxy group Sub.sub.8 is exemplified by at least one group selected from the group consisting of a methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group and hexyloxy group.

[0691] Herein, an alkoxy halide group is exemplified by an alkoxy halide group Sub.sub.9. The alkoxy halide group Sub.sub.9 is provided by substituting the alkoxy group Sub.sub.8 with at least one halogen atom, preferably at least one fluorine atom.

[0692] Herein, an aryloxy group (occasionally referred to as an arylalkoxy group) is exemplified by an arylalkoxy group Sub.sub.10. An aryl group in the arylalkoxy group Sub.sub.10 includes at least one of the aryl group Sub.sub.1 or the heteroaryl group Sub.sub.2.

[0693] The arylalkoxy group Sub.sub.10 herein is represented by —OZ.sub.2. Z.sub.2 is exemplified by the aryl group Sub.sub.1 or the heteroaryl group Sub.sub.2. The arylalkoxy group Sub.sub.10 preferably has 6 to 30 ring carbon atoms, more preferably 6 to 20 ring carbon atoms. The arylalkoxy group Sub.sub.10 is exemplified by a phenoxy group.

[0694] Herein, a substituted amino group is exemplified by a substituted amino group Sub.sub.11. The substituted amino group Sub.sub.11 is exemplified by at least one group selected from the group consisting of an arylamino group Sub.sub.111 and an alkylamino group Sub.sub.112.

[0695] The arylamino group Sub.sub.111 is represented by —NHR.sub.V1 or —N(R.sub.V1).sub.2. R.sub.V1 is exemplified by the aryl group Sub.sub.1. Two R.sub.V1 in —N(R.sub.V1).sub.2 are mutually the same or different.

[0696] The alkylamino group Sub.sub.112 is represented by —NHR.sub.V2 or —N(R.sub.V2).sub.2. R.sub.V2 is exemplified by the alkyl group Sub.sub.3. Two R.sub.V2 in —N(R.sub.V2).sub.2 are mutually the same or different.

[0697] Herein, the alkenyl group is exemplified by an alkenyl group Sub.sub.12. The alkenyl group Sub.sub.12, which is linear or branched, is exemplified by at least one group selected from the group consisting of a vinyl group, propenyl group, butenyl group, oleyl group, eicosapentaenyl group, docosahexaenyl group, styryl group, 2,2-diphenylvinyl group, 1,2,2-triphenylvinyl group, and 2-phenyl-2-propenyl group.

[0698] The alkynyl group herein is exemplified by an alkynyl group Sub.sub.13. The alkynyl group Sub.sub.13 may be linear or branched, and is exemplified by at least one group selected from the group consisting of an ethynyl group, a propynyl group and a 2-phenylethynyl group.

[0699] The alkylthio group herein is exemplified by an alkylthio group Sub.sub.14. The alkylthio group Sub.sub.14 is represented by —SR.sub.V3. R.sub.V3 is exemplified by the alkyl group Sub.sub.3. The alkylthio group Sub.sub.14 preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms.

[0700] The arylthio group herein is exemplified by an arylthio group Sub.sub.15.

[0701] The arylthio group Sub.sub.15 is represented by —SR.sub.V4. R.sub.V4 is exemplified by the aryl group Sub.sub.1. The arylthio group Sub.sub.15 preferably has 6 to 30 ring carbon atoms, more preferably 6 to 20 ring carbon atoms.

[0702] Herein, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, among which a fluorine atom is preferable.

[0703] A substituted phosphino group herein is exemplified by a substituted phosphino group Sub.sub.16. The substituted phosphino group Sub.sub.16 is exemplified by a phenyl phosphanyl group.

[0704] A substituted carbonyl group herein is exemplified by a substituted carbonyl group Sub.sub.17. The substituted carbonyl group Sub.sub.17 is represented by —COY′. Y′ is exemplified by at least one group selected from the group consisting of the aryl group Sub.sub.1, the heteroaryl group Sub.sub.2 and the alkyl group Sub.sub.3. When —COY′ is an arylcarbonyl group, the arylcarbonyl group is exemplified by at least one group selected from the group consisting of a phenyl carbonyl group, diphenyl carbonyl group, naphthyl carbonyl group, and triphenyl carbonyl group.

[0705] An acyl group herein is exemplified by an acyl group Sub.sub.18. The acyl group Sub.sub.18 is represented by —COR′. R′ is exemplified by the alkyl group Sub.sub.3. The acyl group Sub.sub.18 herein is exemplified by at least one group selected from the group consisting of an acetyl group and a propionyl group,

[0706] A substituted phosphoryl group herein is exemplified by a substituted phosphoryl group Sub.sub.19. The substituted phosphoryl group Sub.sub.19 is represented by a formula (P) below.

##STR00218##

[0707] In the formula (P), Ar.sub.P1 and Ar.sub.P2 are any one substituent selected from the group consisting of the above alkyl group Sub.sub.3 and the above aryl group Sub.sub.1.

[0708] An ester group herein is exemplified by an ester group Sub.sub.20. The ester group Sub.sub.20 is exemplified by at least one group selected from the group consisting of an alkyl ester group and an aryl ester group.

[0709] An alkyl ester group herein is exemplified by an alkyl ester group Sub.sub.201. The alky, ester group Sub.sub.201 is represented by —C(═O)OR.sup.E. R.sup.E is exemplified by a substituted or unsubstituted alkyl group Sub.sub.3 described above.

[0710] An aryl ester group herein is exemplified by an aryl ester group Sub.sub.202. The aryl ester group Sub.sub.202 is represented by —C(═O)OR.sup.Ar, R.sup.Ar is exemplified by a substituted or unsubstituted aryl group Sub.sub.1 described above.

[0711] A siloxanyl group herein is exemplified by a siloxanyl group Sub.sub.21. The siloxanyl group Sub.sub.21 is a silicon compound group through an ether bond. The siloxanyl group Sub.sub.21 is exemplified by a tri ethylsiloxanyl group.

[0712] A carbamoyl group herein is represented by —CONH.sub.2.

[0713] A substituted carbamoyl group herein is exemplified by a carbamoyl group Sub.sub.22. The carbamoyl group Sub.sub.22 is represented by —CONH—Ar.sup.C or —CONH—R.sup.C. Ar.sup.C is exemplified by at least one group selected from the group consisting of a substituted or unsubstituted aryl group Sub.sub.1 described above (preferably 6 to 10 ring carbon atoms) and the above-described heteroaryl group Sub.sub.2 (preferably 5 to 14 ring atoms). Ar.sup.C may be a group formed by bonding the aryl group Sub.sub.1 and the heteroaryl group Sub.sub.2.

[0714] R.sup.C is exemplified by a substituted or unsubstituted alkyl group Sub.sub.3 described above (preferably having 1 to 6 carbon atoms).

[0715] A substituted boryl group herein is exemplified by a substituted boryl group Sub.sub.23. The substituted boryl group Sub.sub.23 is represented by a formula (B) below.

##STR00219##

[0716] In the formula (B): Ar.sub.B1 and Ar.sub.B2 are each independently a substituent, or a pair of Ar.sub.B1 and Ar.sub.B2 are mutually bonded to form a ring; and

[0717] Ar.sub.B1 and Ar.sub.B2 as the substituents are each independently a substituent selected from the group consisting of a halogen atom, the above-described aryl group Sub.sub.1, the above-described heteroaryl group Sub.sub.2, the above-described alkyl group Sub.sub.3, the above-described alkyl halide group Sub.sub.4, the above-described alkoxy group Sub.sub.8, the above-described alkoxy halide group Sub.sub.9, the above-described aryloxy group Sub.sub.10, and the above-described arylamino group Sub.sub.11. Ar.sub.B1 and Ar.sub.B2 in the formula (B) are the same or different.

[0718] Herein, “carbon atoms forming a ring (ring carbon atoms)” mean carbon atoms forming a saturated ring, unsaturated ring, or aromatic ring. “Atoms forming a ring (ring atoms)” mean carbon atoms and hetero atoms forming a hetero ring including a saturated ring, unsaturated ring, or aromatic ring.

[0719] Herein, a hydrogen atom includes isotope having different numbers of neutrons, specifically, protium, deuterium and tritium.

[0720] In chemical formulae herein, unless otherwise specified, it is assumed that a hydrogen atom (i.e., protium, deuterium and tritium) is bonded to each of bondable positions that are not annexed with signs “R” or the like or “D” representing a deuterium.

[0721] Hereinafter, an alkyl group Sub.sub.3 means at least one group of a linear alkyl group Sub.sub.31, a branched alkyl group Sub.sub.32, or a cyclic alkyl group Sub.sub.33 described in “Description of Each Substituent.”

[0722] Similarly, a substituted silyl group Sub.sub.5 means at least one group of an alkylsilyl group Sub.sub.51 or an arylsilyl group Sub.sub.52.

[0723] Similarly, a substituted amino group Sub.sub.11 means at least one group of an arylamino group Sub.sub.111 or an alkylamino group Sub.sub.112.

[0724] Herein, a substituent for a “substituted or unsubstituted” group is exemplified by a substituent R.sub.F1. The substituent R.sub.F1 is at least one group selected from the group consisting of an aryl group Sub.sub.1, heteroaryl group Sub.sub.2, alkyl group Sub.sub.3, alkyl halide group Sub.sub.4, substituted silyl group Sub.sub.5, alkylsulfonyl group Sub.sub.6, aralkyl group Sub.sub.7, alkoxy group Sub.sub.8, alkoxy halide group Sub.sub.9, arylalkoxy group Sub.sub.10, substituted amino group Sub.sub.11, alkenyl group Sub.sub.12, alkynyl group Sub.sub.13, alkylthio group Sub.sub.14, arylthio group Sub.sub.15, substituted phosphino group Sub.sub.16, substituted carbonyl group Sub.sub.17, acyl group Sub.sub.13, substituted phosphoryl group Sub.sub.19, ester group Sub.sub.20, siloxanyl group Sub.sub.21, carbamoyl group Sub.sub.22, substituted boryl group Sub.sub.23, unsubstituted amino group, unsubstituted silyl group, halogen atom, cyano group, hydroxy group, nitro group, and carboxy group.

[0725] Specific examples and preferable examples of the substituent R.sub.F1 are the same as those of the substituents described in “Description of Each Substituent” (e.g., an aryl group Sub.sub.1, heteroaryl group Sub.sub.2, alkyl group Sub.sub.3, alkyl halide group Sub.sub.4, substituted silyl group Sub.sub.5, alkylsulfonyl group Sub.sub.6, aralkyl group Sub.sub.7, alkoxy group Sub.sub.8, alkoxy halide group Sub.sub.9, arylalkoxy group Sub.sub.10, substituted amino group Sub.sub.11, alkenyl group Sub.sub.12, alkynyl group Sub.sub.13, alkylthio group Sub.sub.14, arylthio group Sub.sub.15, substituted phosphino group Sub.sub.16, substituted carbonyl group Sub.sub.17, acyl group Sub.sub.18, substituted phosphoryl group Sub.sub.19, ester group Sub.sub.20, siloxanyl group Sub.sub.21, carbamoyl group Sub.sub.22, and substituted boryl group Sub.sub.23).

[0726] The substituent R.sub.F1 for a “substituted or unsubstituted” group may be further substituted by at least one group (hereinafter, also referred to as a substituent R.sub.F2) selected from the group consisting of an aryl group Sub.sub.1, heteroaryl group Sub.sub.2, alkyl group Sub.sub.3, alkyl halide group Sub.sub.4, substituted silyl group Sub.sub.5, alkylsulfonyl group Sub.sub.6, aralkyl group Sub.sub.7, alkoxy group Sub.sub.8, alkoxy halide group Sub.sub.9, arylalkoxy group Sub.sub.10, substituted amino group Sub.sub.11, alkenyl group Sub.sub.12, alkynyl group Sub.sub.13, alkylthio group Sub.sub.14, arylthio group Sub.sub.15, substituted phosphino group Sub.sub.16, substituted carbonyl group Sub.sub.17, acyl group Sub.sub.18, substituted phosphoryl group Sub.sub.19, ester group Sub.sub.20, siloxanyl group Sub.sub.21, carbamoyl group Sub.sub.22, substituted boryl group Sub.sub.23, unsubstituted amino group, unsubstituted silyl group, halogen atom, cyano group, hydroxy group, nitro group, and carboxy group. Moreover, a plurality of substituents R.sub.F2 may be bonded to each other to form a ring.

[0727] “Unsubstituted” for a “substituted or unsubstituted” group means that a group is not substituted by the above-described substituent R.sub.F1 but bonded with a hydrogen atom.

[0728] Herein, “XX to YY carbon atoms” in the description of “substituted or unsubstituted ZZ group having XX to YY carbon atoms” represent carbon atoms of an unsubstituted ZZ group and do not include carbon atoms of the substituent R.sub.F1 of the substituted ZZ group.

[0729] Herein, “XX to YY atoms” in the description of “substituted or unsubstituted ZZ group having XX to YY atoms” represent atoms of an unsubstituted ZZ group and do not include atoms of the substituent R.sub.F1 of the substituted ZZ group.

[0730] The same description as the above applies to “substituted or unsubstituted” in compounds or partial structures thereof described herein.

[0731] Herein, when the substituents are bonded to each other to form a ring, the ring is structured to be a saturated ring, an unsaturated ring, an aromatic hydrocarbon ring or a hetero ring.

[0732] Herein, examples of the aromatic hydrocarbon group in the linking group include a divalent or multivalent group obtained by eliminating one or more atoms from the above monovalent aryl group Sub.sub.1.

[0733] Herein, examples of the heterocyclic group in the linking group include a divalent or multivalent group obtained by eliminating one or more atoms from the above monovalent heteroaryl group Sub.sub.2.

EXAMPLES

Compounds

[0734] Structures of a compound M3a, a compound M3b, a compound M3c, and a compound M3d each serving as the compound M3, and structures of compounds TADF1 to TADF3 each serving as the compound M2, the compounds being used for manufacturing organic EL devices, are shown below.

##STR00220## ##STR00221## ##STR00222##

[0735] Structures of compounds used for manufacturing organic EL devices in Comparatives are shown below.

##STR00223## ##STR00224## ##STR00225##

[0736] Structures of other compounds used for manufacturing organic EL devices according to Examples and Comparatives are shown below.

##STR00226## ##STR00227## ##STR00228##

Manufacturing 1 of Organic EL Device

[0737] Organic EL devices were manufactured and evaluated as follows.

Example 1

[0738] A glass substrate (size: 25 mm×75 mm×1.1 mm thick, manufactured by Geomatec Co., Ltd.) having an ITO transparent electrode (anode) was ultrasonic-cleaned in isopropyl alcohol for five minutes, and then UV/ozone-cleaned for one minute. A film of ITO was 130 nm thick.

[0739] After the glass substrate having the transparent electrode line was cleaned, the glass substrate was mounted on a substrate holder of a vacuum evaporation apparatus. Firstly, a compound HT and a compound HA were co-deposited on a surface of the glass substrate where the transparent electrode line was provided in a manner to cover the transparent electrode, thereby forming a 10-nm-thick hole injecting layer. The concentrations of the compound HT and the compound HA in the hole injecting layer were 97 mass % and 3 mass %, respectively.

[0740] Next, the compound HT was vapor-deposited on the hole injecting layer to form a 200-nm-thick hole transporting layer.

[0741] Next, a compound EBL was vapor-deposited on the hole transporting layer to form a 10-nm-thick electron blocking layer.

[0742] Next, the compound M3a serving as the compound M3, the compound TADF1 serving as the compound M2, and a compound RD serving as the compound M1 were co-deposited on the electron blocking layer to form a 25-nm-thick emitting layer. The concentrations of the compound M3a, the compound TADF1, and the compound RD in the emitting layer were 74 mass %, 25 mass %, and 1 mass %, respectively.

[0743] Next, the compound HBL was vapor-deposited on the emitting layer to form a 10-nm-thick hole blocking layer (first layer).

[0744] Next, a compound ET was vapor-deposited on the hole blocking layer to form a 30-nm-thick electron transporting layer.

[0745] Lithium fluoride (LiF) was vapor-deposited on the electron transporting layer to form a 1-nm-thick electron injectable electrode (cathode).

[0746] Subsequently, metal aluminum (Al) was vapor-deposited on the electron injectable electrode to form an 80-nm-thick metal Al cathode.

[0747] A device arrangement of the organic EL device of Example 1 is roughly shown as follows.

ITO (130)/HT:HA (10, 97%:3%)/HT (200)/EBL (10)/M3a:TADF1:RD (25, 74%:25%:1%)/HBL (10)/ET (30)/LiF (1)/Al (80)

[0748] Numerals in parentheses represent a film thickness (unit: nm). (97%:3%) represents a ratio (mass %) between the compound HT and the compound HA in the hole injecting layer, and numerals represented by percentage (74%:25%:1%) indicate a ratio (mass %) between the compound M3a, the compound TADF1, and the compound RD in the emitting layer.

Comparatives 1 to 3

[0749] Organic EL devices of Comparatives 1 to 3 were manufactured as in Example 1 except that the compounds M3a and TADF1 in the emitting layer of Example 1 were replaced with the compounds listed in Table 1.

Evaluation 1 of Organic EL Device

[0750] For the organic EL devices manufactured in Example 1 and Comparatives 1 to 3, the following evaluations were performed. The results are shown in Table 1. Although a compound Ref-1 used in Comparatives 1 and 3 does not correspond to the compound M3, Ref-1 is shown in the same column as the compound M3a in Example 1 for convenience. Although a compound Ref-2 used in Comparatives 1 and 2 does not correspond to the compound M2, Ref-2 is shown in the same column as the compound TADF1 in Example 1 for convenience.

Main Peak Wavelength (λp)

[0751] Voltage was applied on the organic EL devices such that a current density of the organic EL device was 10 mA/cm.sup.2, where spectral radiance spectrum was measured by a spectroradiometer CS-2000 (manufactured by Konica Minolta, Inc.). The main peak wavelength λp (unit: nm) was calculated based on the obtained spectral radiance spectrum.

External Quantum Efficiency EQE

[0752] Voltage was applied on the organic EL devices such that a current density was 10 mA/cm.sup.2, where spectral radiance spectrum was measured by a spectroradiometer CS-2000 (manufactured by Konica Minolta, Inc.). The external quantum efficiency EQE (unit: %) was calculated based on the obtained spectral-radiance spectra, assuming that the spectra was provided under a Lambertian radiation.

[0753] EQE (%) of Comparative 1 was set to be 100 and EQE (%) of each of Example and Comparatives was obtained as an “EQE (relative value: %)” using a numerical formula (numerical formula 100) below.

EQE (relative value: %) of each of Example and Comparatives=(EQE (%) of each of Example and Comparatives/EQE (%) of Comparative 1)×100  (Numerical Formula 100)

Drive Voltage

[0754] A voltage (unit: V) was measured when current was applied between the anode and the cathode such that a current density was 10 mA/cm.sup.2.

[0755] “Drive Voltage (V)” of Comparative 1 was set to be 100, and “Drive Voltage (V)” of each of Example and Comparatives was determined as a “Drive Voltage (relative value: %)” using a numerical formula (numerical formula 101) below.

Drive Voltage (relative value: %) of each of Example and Comparatives=(Drive Voltage (V) of each of Example and Comparatives/Drive Voltage (V) of Comparative 1)×100  (Numerical Formula 101)

Lifetime LT95

[0756] Voltage was applied on the organic EL devices such that a current density was 50 mA/cm.sup.2, a time (unit: hr) elapsed before a luminance intensity was reduced to 95% of the initial luminance intensity was measured using a spectroradiometer CS-200 (manufactured by Konica Minolta, Inc.).

[0757] Hereinafter, the time elapsed before the luminance intensity is reduced to 95% of the initial luminance intensity is referred to as “Lifetime LT95(h).”

[0758] “Lifetime LT95 (h)” of Comparative 1 was set to be 100, and “Lifetime LT95 (h)” of each of Example and Comparatives was determined as a “Lifetime LT95 (relative value: %)” using a numerical formula (numerical formula 102) below.

Lifetime LT95 (relative value: %) of each of Example and Comparatives=(Lifetime LT95(h) of each of Example and Comparatives/Lifetime LT95(h) of Comparative 1)×100  (Numerical Formula 102)

TABLE-US-00001 TABLE 1 Device evaluation resuts Drive Compound M3 Compound M2 Compound M1 voltage EQE LT95 S.sub.1 S.sub.1 ΔST λ S.sub.1 λ λ.sub.p (Relative (Relative (Relative Type [eV] Type [eV] [eV] [nm] Type [eV] [nm] [nm] value: %) value: %) value: %) Ex 1 M3a 3.52 TADF1 2.32 <0.01 545 RD 2.02 609 621 100 101 270 Comp 1 Ref-1 3.41 Ref-2 2.32 <0.01 545 RD 2.02 609 621 100 100 100 Comp 2 M3a 3.52 Ref-2 2,32 <0.01 545 RD 2.02 609 631 100 102 160 Comp 3 Ref-1 3.41 TADF1 2.32 <0.01 545 RD 2.02 609 631 100 191 100

[0759] Example 1 in which the compound M3a having deuterium atoms and the compound TADF1 having deuterium atoms were contained in the emitting layer had a longer lifetime than Comparatives 1 to 3 in which at least one of the compound M3a or the compound TADF1 in Example 1 was replaced with at least one “compound having no deuterium atom”.

Manufacturing 2 of Organic EL Device

[0760] Organic EL devices were manufactured and evaluated as follows,

Example 2

[0761] A glass substrate (size: 25 mm×75 mm×1.1 mm thick, manufactured by Geomatec Co., Ltd.) having an ITO transparent electrode (anode) was ultrasonic-cleaned in isopropyl alcohol for five minutes, and then UV/ozone-cleaned for one minute, A film of ITO was 130 nm thick.

[0762] After the glass substrate having the transparent electrode line was cleaned, the glass substrate was mounted on a substrate holder of a vacuum evaporation apparatus, Firstly, the compound MT and the compound HA were co-deposited on a surface of the glass substrate where the transparent electrode line was provided in a manner to cover the transparent electrode, thereby forming a 10-nm-thick hole injecting layer. The concentrations of the compound HT and the compound HA in the hole injecting layer were 97 mass % and 3 mass %, respectively.

[0763] Next, the compound HT2 was vapor-deposited on the hole injecting layer to form a 110-nm-thick first hole transporting layer on the hole injecting layer.

[0764] Next, the compound EBL was vapor-deposited on the first hole transporting layer to form a 5-nm-thick second hole transporting layer.

[0765] Next, the compound Ref-1 was vapor-deposited on the second hole transporting layer to form a 5-nm-thick electron blocking layer.

[0766] Next, the compound M3c serving as the compound M3 and the compound TADF2 serving as the compound M2 were co-deposited on the electron blocking layer to form a 25-nm-thick emitting layer. The concentrations of the compound M3c and the compound TADF2 in the emitting layer were 50 mass % and 50 mass %, respectively.

[0767] Next, the compound HBL was vapor-deposited on the emitting layer to form a 5-nm-thick hole blocking layer (first layer).

[0768] Next, the compound ET was vapor-deposited on the hole blocking layer to form a 50-nm-thick electron transporting layer.

[0769] Lithium fluoride (LiF) was vapor-deposited on the electron transporting layer to form a 1-nm-thick electron injectable electrode (cathode).

[0770] Subsequently, metal aluminum (Al) was vapor-deposited on the electron injectable electrode to form an 80-nm-thick metal Al cathode.

[0771] A device arrangement of the organic EL device of Example 2 is roughly shown as follows.

ITO (130)/HT:HA (10.97%:3%)/HT2 (110)/EBL (5)/Ref-1 (5)/M3c:TADF2 (25.50%:50%)/HBL (5)/ET (50)/LiF (1)/Al (80)

[0772] Numerals in parentheses represent a film thickness (unit: nm). (97%:3%) represents a ratio (mass %) between the compound HT and the compound HA in the hole injecting layer, and numerals represented by percentage (50%:50%) indicate a ratio (mass %) between the compound M3c and the compound TADF2 in the emitting layer.

Comparatives 4 to 6

[0773] Organic EL devices of Comparatives 4 to 6 were manufactured as in Example 2 except that the compounds M3c and TADF2 in the emitting layer of Example 2 were replaced with the compounds listed in Table 2.

Evaluation 2 of Organic EL Device

[0774] For the organic EL devices manufactured in Example 2 and Comparatives 4 to 6, the following evaluations were performed. The results are shown in Table 2. Although a compound Ref-3 used in Comparatives 4 and 6 does not correspond to the compound M3, Ref-3 is shown in the same column as the compound M3c in Example 2 for convenience. Although a compound Ref-4 used in Comparatives 4 and 5 does not correspond to the compound M2, Ref-4 is shown in the same column as the compound TADF2 in Example 2 for convenience.

Main Peak Wavelength (λp)

[0775] The main peak wavelength λp (unit: nm) was determined by the same method as that used in Example 1.

External Quantum Efficiency EQE

[0776] The external quantum efficiency EQE (unit: %) was calculated by the same method as that used in Example 1.

[0777] EQE (%) of Comparative 4 was set to be 100, and EQE (%) of each of Example and Comparatives was determined as an “EQE (relative value: %)” using a numerical formula in which EQE (%) of Comparative 1 was replaced with EQE (%) of Comparative 4 in the numerical formula (numerical formula 100).

Drive Voltage

[0778] The voltage (unit: V) was measured by the same method as that used in Example 1.

[0779] Drive Voltage (V) of Comparative 4 was set to be 100, and Drive Voltage (V) of each of Example and Comparatives was determined as a “Drive Voltage (relative value: %)” using a numerical formula in which Drive Voltage (V) of Comparative 1 was replaced with Drive Voltage (V) of Comparative 4 in the numerical formula (numerical formula 101).

Lifetime LT95

[0780] The time (unit: h) elapsed before the luminance intensity was reduced to 95% of the initial luminance intensity was measured by the same method as that used in Example 1.

[0781] Lifetime LT95 (h) of Comparative 4 was set to be 100, and Lifetime LT95 (h) of each of Example and Comparatives was determined as a “Lifetime LT95 (relative value: %)” using a numerical formula in which Lifetime LT95 (h) of Comparative 1 was replaced with Lifetime LT95 (h) of Comparative 4 in the numerical formula (numerical formula 102).

TABLE-US-00002 TABLE 2 Device evaluation results Drive Compound M3 Compound M2 voltage EQE LT95 S.sub.1 S.sub.1 ΔST λ λ.sub.p (Relative (Relative (Relative Type [eV] Type [eV] [eV] [nm] [nm] value: %) value: %) value: %) Ex 2 M3c 3.52 TADF2 2.57 <0.01 512 550 100 100 135 Comp. 4 Ref-3 3.50 Ref-4 2.52 <0.01 511 550 100 100 100 Comp. 5 M3c 3.52 Ref-4 2.52 <0.01 511 550 100 100 120 Comp. 6 Ref-3 3.50 TADF2 2.57 <0.01 512 550 100 100 120

[0782] Example 2 in which the compound M3c having deuterium atoms and the compound TADF2 having deuterium atoms were contained in the emitting layer had a longer lifetime than Comparatives 4 to 6 in which at least one of the compound M3c or the compound TADF2 in Example 2 was replaced with at least one “compound having no deuterium atom”.

Manufacturing 3 of Organic EL Device

Example 3 and Comparatives 7 to 9

[0783] Organic EL devices of Example 3 and Comparatives 7 to 9 were manufactured as in Example 1 except that the compounds M3a and TADF1 in the emitting layer of Example 1 were replaced with the compounds listed in Table 3.

Evaluation 3 of Organic EL Device

[0784] For the organic EL devices manufactured in Example 3 and Comparatives 7 to 9, the following evaluations were performed. The results are shown in Table 3. Although a compound Ref-5 used in Comparatives 7 and 9 does not correspond to the compound M3, Ref-5 is shown in the same column as the compound M3d in Example 3 for convenience. Although the compound Ref-2 used in Comparatives 7 and 8 does not correspond to the compound M2, Ref-2 is shown in the same column as the compound TADF1 in Example 3 for convenience.

Main Peak Wavelength (λp)

[0785] The main peak wavelength λp (unit: nm) was determined by the same method as that used in Example 1.

Lifetime LT95

[0786] The time (unit: h) elapsed before the luminance intensity was reduced to 95% of the initial luminance intensity was measured by the same method as that used in Example 1.

[0787] Lifetime LT95 (h) of Comparative 7 was set to be 100, and Lifetime LT95 (h) of each of Example and Comparatives was determined as a “Lifetime LT95 (relative value: %)” using a numerical formula in which Lifetime LT95 (h) of Comparative 1 was replaced with Lifetime LT95 (h) of Comparative 7 in the numerical formula (numerical formula 102).

TABLE-US-00003 TABLE 3 Device evaluation results Compound M3 Compound M2 Compound M1 LT95 S.sub.1 S.sub.1 ΔST λ S.sub.1 λ λ.sub.p (Relative Type [eV] Type [eV] [eV] [nm] Type [eV] [nm] [nm] value: %) Ex. 3 M3d 3.48 TADF1 2.32 <0.01 545 RD 2.02 609 621 130 Comp. 7 Ref-5 3.48 Ref-2 2.32 <0.01 545 RD 2.02 609 621 100 Comp. 8 M3d 3.48 Ref-2 2.32 <0.01 545 RD 2.02 609 621 115 Comp. 9 Ref-5 3.48 TADF1 2.32 <0.01 545 RD 2.02 609 621 115

[0788] Example 3 in which the compound M3d having deuterium atoms and the compound TADF1 having deuterium atoms were contained in the emitting layer had a longer lifetime than Comparatives 7 to 9 in which at least one of the compound M3d or the compound TADF1 in Example 3 was replaced with at least one “compound having no deuterium atom”.

Manufacturing 4 of Organic EL Device

[0789] Organic EL devices were manufactured and evaluated as follows.

Example 4

[0790] A glass substrate (size: 25 mm×75 mm×1.1 mm thick, manufactured by Geomatec Co., Ltd.) having an ITO transparent electrode (anode) was ultrasonic-cleaned in isopropyl alcohol for five minutes, and then UV/ozone-cleaned for one minute. A film of ITO was 130 nm thick.

[0791] After the glass substrate having the transparent electrode line was cleaned, the glass substrate was mounted on a substrate holder of a vacuum evaporation apparatus. Firstly, the compound HT and the compound HA were co-deposited on a surface of the glass substrate where the transparent electrode line was provided in a manner to cover the transparent electrode, thereby forming a 10-nm-thick hole injecting layer. The concentrations of the compound HT and the compound HA in the hole injecting layer were 97 mass % and 3 mass %, respectively.

[0792] Next, the compound HT2 was vapor-deposited on the hole injecting layer to form a 110-nm-thick first hole transporting layer on the hole injecting layer.

[0793] Next, the compound EBL was vapor-deposited on the first hole transporting layer to form a 5-nm-thick second hole transporting layer.

[0794] Next, the compound Ref-1 was vapor-deposited on the second hole transporting layer to form a 5-nm-thick electron blocking layer.

[0795] Next, the compound M3b serving as the compound M3 and the compound TADF3 serving as the compound M2 were co-deposited on the electron blocking layer to form a 25-nm-thick emitting layer. The concentrations of the compound M3b and the compound TADF3 in the emitting layer were 75 mass % and 25 mass %, respectively.

[0796] Next, the compound Ref-5 was vapor-deposited on the emitting layer to form a 5-nm-thick hole blocking layer (first layer).

[0797] Next, the compound ET was vapor-deposited on the hole blocking layer to form a 50-nm-thick electron transporting layer.

[0798] Lithium fluoride (LiF) was vapor-deposited on the electron transporting layer to form a 1-nm-thick electron injectable electrode (cathode).

[0799] Subsequently, metal aluminum (Al) was vapor-deposited on the electron injectable electrode to form an 80-nm-thick metal Al cathode.

[0800] A device arrangement of the organic EL device of Example 4 is roughly shown as follows.

ITO (130)/HT:HA (10, 97%:3%)/HT2 (110)/EBL (5)/Ref-1 (5)/M3b:TADF3 (25, 75%:25%)/Ref-5 (5)/ET (50)/LiF (1)/Al (80)

[0801] Numerals in parentheses represent a film thickness (unit: nm). (97%:3%) represents a ratio (mass %) between the compound HT and the compound HA in the hole injecting layer, and numerals represented by percentage (75%:25%) indicate a ratio (mass %) between the compound M3b and the compound TADF3 in the emitting layer.

Comparatives 10 to 12

[0802] Organic EL devices of Comparatives 10 to 12 were manufactured as in Example 4 except that the compounds M3b and TADF3 in the emitting layer of Example 4 were replaced with the compounds listed in Table 4.

Evaluation 4 of Organic EL Device

[0803] For the organic EL devices manufactured in Example 4 and Comparatives 10 to 12, the following evaluations were performed. The results are shown in Table 4. Although a compound Ref-6 used in Comparatives 10 and 12 does not correspond to the compound M3, Ref-6 is shown in the same column as the compound M3b in Example 4 for convenience. Although a compound Ref-7 used in Comparatives 10 and 11 does not correspond to the compound M2, Ref-7 is shown in the same column as the compound TADF3 in Example 4 for convenience.

Main Peak Wavelength (λp)

[0804] The main peak wavelength λp (unit: nm) was determined by the same method as that used in Example 1.

Lifetime LT95

[0805] The time (unit: h) elapsed before the luminance intensity was reduced to 95% of the initial luminance intensity was measured by the same method as that used in Example 1.

[0806] Lifetime LT95 (h) of Comparative 10 was set to be 100, and Lifetime LT95 (h) of each of Example and Comparatives was determined as a “Lifetime LT95 (relative value: %)” using a numerical formula in which Lifetime LT95 (h) of Comparative 1 was replaced with Lifetime LT95 (h) of Comparative 10 in the numerical formula (numerical formula 102).

TABLE-US-00004 TABLE 4 Device evaluation Compound results M3 Compound M2 LT95 S.sub.1 S.sub.1 ΔST λ λ.sub.p (Relative Type [eV] Type [eV] [eV] [nm] [nm] value: %) Ex. 4 M3b 3.42 TADF3 2.79 0.03 503 519 140 Comp. Ref-6 3.42 Ref-7 2.79 0.03 503 519 100 10 Comp. M3b 3.42 Ref-7 2.79 0.03 503 519 125 11 Comp. Ref-6 3.42 TADF3 2.79 0.03 503 519 125 12

[0807] Example 4 in which the compound M3b having deuterium atoms and the compound TADF3 having deuterium atoms were contained in the emitting layer had a longer lifetime than Comparatives 10 to 12 in which at least one of the compound M3b or the compound TADF3 in Example 4 was replaced with at least one “compound having no deuterium atom”.

Evaluation of Compounds

[0808] Physical properties of the compounds described in Tables 1 to 4 and Synthesis Examples described later were measured by the following methods.

Thermally Activated Delayed Fluorescence

Delayed Fluorescence of Compound TADF1

[0809] Thermally activated delayed fluorescence characteristics were checked by measuring transient photoluminescence (PL) using a device shown in FIG. 2. The compound TADF1 was dissolved in toluene to prepare a dilute solution with an absorbance of 0.05 or less at the excitation wavelength to eliminate the contribution of self-absorption. In order to prevent quenching due to oxygen, the sample solution was frozen and degassed and then sealed in a cell with a lid under an argon atmosphere to obtain an oxygen-free sample solution saturated with argon.

[0810] The fluorescence spectrum of the above sample solution was measured with a spectrofluorometer FP-8600 (manufactured by JASCO Corporation), and the fluorescence spectrum of a 9,10-diphenylanthracene ethanol solution was measured under the same conditions. Using the fluorescence area intensities of both spectra, the total fluorescence quantum yield was calculated by an equation (1) in Morris et al. J. Phys. Chem. 80 (1976) 969.

[0811] Prompt emission was observed immediately when the excited state was achieved by exciting the compound TADF1 with a pulse beam (i.e., a beam emitted from a pulse laser) having a wavelength to be absorbed by the compound TADF1, and Delay emission was observed not immediately when the excited state was achieved but after the excited state was achieved. The delayed fluorescence in Examples means that an amount of Delay Emission is 5% or more with respect to an amount of Prompt Emission. Specifically, provided that the amount of Prompt emission is denoted by X.sub.P and the amount of Delay emission is denoted by X.sub.D, the delayed fluorescence means that a value of X.sub.D/X.sub.P is 0.05 or more.

[0812] An amount of Prompt emission, an amount of Delay emission and a ratio between the amounts thereof can be obtained according to the method as described in “Nature 492, 234-238, 2012” (Reference Document 1). The amount of Prompt emission and the amount of Delay emission may be calculated using a device different from one described in Reference Document 1 or one shown in FIG. 2.

[0813] It was found that the amount of Delay Emission was 5% or more with respect to the amount of Prompt Emission in the compound TADF1.

[0814] Specifically, the value of X.sub.D/X.sub.P in the compound TADF1 was 0.05 or more.

Delayed Fluorescence of Compounds TADF2 to TADF3 and Comparative Compounds Ref-2, Ref-4, and Ref-7

[0815] Delayed fluorescence of each of the compounds TADF2 to TADF3 and comparative compounds Ref-2, Ref-4, and Ref-7 was checked in the same manner except that each of the compounds TADF2 to TADF3 and comparative compounds Ref-2, Ref-4, and Ref-7 was used instead of the compound TADF1.

[0816] It was found that the value of X.sub.D/X.sub.P in each of the compounds TADF2 to TADF3 and comparative compounds Ref-2, Ref-4, and Ref-7 was 0.05 or more

Singlet Energy S.SUB.1

[0817] A singlet energy S.sub.1 of each of the compounds M3a, M3b, M3c, and M3d, the compounds TADF1 to TADF3, the comparative compounds Ref-1 to Ref-7, and the compound RD was measured by the solution method described above. The results are shown in Tables 1 to 4.

Energy Gap at 77K

[0818] An energy gap T.sub.77K at 77K of each of the compounds M3a, M3b, M3c, and M3d, the compounds TADF1 to TADF3, and the comparative compounds Ref-1 to Ref-7 was measured by the method for measuring the energy gap T.sub.77K described in the “Relationship between Triplet Energy and Energy Gap at 77K”.

ΔST

[0819] ΔST was calculated based on the measured singlet energy S.sub.1 and energy gap T.sub.77K at 77K.

[0820] ΔST of each of the compounds TADF1 to TADF2 and the comparative compounds Ref-2 and Ref-4 was less than 0.01 eV.

[0821] ΔST of each of the compound TADF3 and the comparative compound Ref-7 was 0.03 eV.

Energy Gap T.SUB.77K

[0822] T.sub.77K of the compound M3a was 2.80 eV.

[0823] T.sub.77K of the compound M3b was 2.97 eV.

T.sub.77K of the compound M3c was 2.74 eV.
T.sub.77K of the compound M3d was 2.71 eV.
T.sub.77K of the comparative compound Ref-1 was 2.69 eV.
T.sub.77K of the comparative compound Ref-3 was 2.74 eV.
T.sub.77K of the comparative compound Ref-5 was 2.71 eV.

[0824] T.sub.77K of the comparative compound Ref-6 was 2.89 eV.

Main Peak Wavelength λ of Compound

[0825] A main peak wavelength λ of a compound was measured by the following method.

[0826] A toluene solution of each of measurement target compounds at a concentration of 5 μmol/L was prepared and put in a quartz cell. An emission spectrum (ordinate axis: emission intensity, abscissa axis: wavelength) of each sample was measured at a normal temperature (300K). In Examples, the emission spectrum was measured using a spectrophotometer manufactured by Hitachi, Ltd. (device name: F-7000). It should be noted that the machine for measuring the emission spectrum is not limited to the machine used herein. A peak wavelength of the emission spectrum exhibiting the maximum luminous intensity was defined as a main peak wavelength λ.

Synthesis of Compounds

(1) Synthesis Example 1: Synthesis of Compound M3a

[0827] ##STR00229##

[0828] Under nitrogen atmosphere, xylene (50 mL) was added to a mixture of 9H-carbazole-1,2,3,4,5,6,7,8-d8 (1.58 g, 9.00 mmol), 4,4′-dibromo-1,1′-biphenyl (1.40 g, 4.50 mmol), palladium acetate (101.0 mg, 0.45 mmol), tri-tert-butylphosphonium tetrafluoroborate (261.1 mg, 0.90 mmol), and sodium tert-butoxide (2.59 g, 27.0 mmol), and the resulting mixture was stirred at 130 degrees C. for seven hours. After completion of the reaction, the solid was filtered out and recrystallized with toluene to obtain a compound M3a (1.54 g, a yield of 68%). The obtained compound was identified as the compound M3a by analysis according to LC-MS (Liquid chromatography mass spectrometry),

(2) Synthesis Example 2: Synthesis of Compound M3b

(2-1) Synthesis of Intermediate 1

[0829] ##STR00230##

[0830] Under nitrogen atmosphere, 1,4-dioxane (70 mL) was added to a mixture of 12H-benzofuro[2,3-a]carbazole (3.60 g, 14.0 mmol), 4-bromo-4′-chloro-1,1′-biphenyl (4.49 g, 16.8 mmol), copper(I) iodide (2.67 g 14.0 mmol), trans-1,2-cyclohexanediamine (3.20 g, 3.37 mL, 28.0 mmcl), and potassium phosphate (8.92 g, 42.0 mmol), and the resulting mixture was stirred at 100 degrees C. for eight hours. After completion of the reaction, the solid was removed by filtration using a Celite pad, the solvent was distilled off, and recrystallization was then performed with toluene to obtain an intermediate 1 (5.96 g, a yield of 96%). The obtained solid was identified as the intermediate 1 by analysis of LC-MS.

(2-2) Synthesis of Compound M3b

[0831] ##STR00231##

[0832] Under nitrogen atmosphere, xylene (40 mL) was added to a mixture of the intermediate 1 (3.11 g, 7.00 mmol), 9H-carbazole-1,2,3,4,5,6,7,8-d8 (1.23 g, 7.00 mmol), palladium acetate (157.2 mg, 0.70 mmol), SPhos (574.8 mg, 0.14 mmol), and potassium phosphate (4.46 g, 21.0 mmol), and the resulting mixture was stirred at 130 degrees C. for 12 hours. After completion of the reaction, the solid was filtered out and recrystallized with toluene to obtain a compound M3b (3.62 g, a yield of 75%). The obtained compound was identified as the compound M3b by analysis of LC-MS.

(3) Synthesis Example 3: Synthesis of Compound M3c

[0833] ##STR00232##

[0834] Under nitrogen atmosphere, xylene (40 mL) was added to a mixture of 9H-carbazole-1,2,3,4,5,6,7,8-d8 (1.40 g, 8.00 mmol), 2-(4′-bromo-[1,1′-biphenyl]-4-yl)dibenzo[b,d]furan (3.19 g, 8.00 mmol), palladium acetate (35.9 mg, 0.16 mmol), tri-tert-butylphosphonium tetrafluoroborate (92.8 mg, 0.32 mmol), and sodium tert-butoxide (2.31 g, 24.0 mmol), and the resulting mixture was stirred at 130 degrees C. for four hours. After completion of the reaction, the solid was filtered out and recrystallized with toluene to obtain a compound M3c (2.70 g, a yield of 68%). The obtained compound was identified as the compound M3c by analysis of LC-MS.

(4) Synthesis Example 4: Synthesis of Compound TADF1

(4-1) Synthesis of Intermediate P2

[0835] ##STR00233##

[0836] Under nitrogen atmosphere, into a 1000-mL three-necked flask, an intermediate A2 (1.16 g, 5.35 mmol), carbazole-1,2,3,4:5,6,7:8-d8 (with a deuteration ratio of 98% was used) (3 g, 17.1 mmol), potassium carbonate (3.5 g, 25.7 mmol), and DMF (30 mL) were put and stirred at 0 degrees C. for nine hours. The reaction mixture was added to a saturated aqueous solution (30 mL) of ammonium chloride. The deposited solid was purified by silica-gel column chromatography to obtain a yellow solid (3.0 g). The obtained solid was identified as an intermediate P2 (a yield of 82%) by analysis of ASAP-MS,

(4-2) Synthesis of Intermediates C2 and D2

[0837] ##STR00234##

[0838] Under nitrogen atmosphere, to a 1-L three-necked flask, 4-bromodibenzothiophene (26.0 g, 100 mmol), 2-chloro-4-methylaniline (17 g, 120 mmol), tris(dibenzylideneacetone)dipalladium(0) (Pd.sub.2dba.sub.3) (0.9 g, 1 mmol), tri-tert-butylphosphonium tetrafluoroborate (P(t-Bu).sub.3HBF.sub.4) (2.3 g, 8 mmol), sodium tert-butoxide (NaOtBu) (11.5 g, 120 mmol) and toluene (350 mL) were added, heated at 60 degrees C. for seven hours with stirring, and subsequently cooled to the room temperature (25 degrees C.). The reaction solution was purified by silica-gel column chromatography to obtain a white solid (26 g), The obtained solid was identified as an intermediate C2 (a yield of 80%) by GC-MS.

[0839] Under nitrogen atmosphere, to a 1-L three-necked flask, an intermediate C (26.0 g. 80 mmol), 1,3-bis(2,6-diisopropylphenyl)imidazolium chloride (IPrHCl) (1.4 g, 3.2 mmol), palladium(II) acetate (Pd(OAc).sub.2) (0.36 g, 1.6 mmol), potassium carbonate (22.0 g, 160 mmol), and N,N-dimethylacetamide (DMAc) (400 mL) were added, stirred at 130 degrees C. for seven hours, and subsequently cooled to room temperature (25 degrees C.). The reaction solution was purified by silica-gel column chromatography to obtain a white solid (21 g). The obtained solid was identified as an intermediate D2 (a yield of 91%) by GC-MS.

(4-3) Synthesis of TADF1

[0840] ##STR00235##

[0841] Under nitrogen atmosphere, into a 100-mL three-necked flask, the intermediate P2 (2.6 g, 3.8 mmol), the intermediate D2 (1.6 g, 5.7 mmol), potassium carbonate (1.2 g, 8.9 mmol), and DMF (30 mL) were put and stirred at 115 degrees C. for six hours. To the reaction mixture, a saturated aqueous solution (50 mL) of ammonium chloride was added. The deposited solid was purified by silica-gel column chromatography to obtain a red solid (2.5 g). The obtained solid was identified as TADF1 (a yield of 70%) by analysis of ASAP-MS.

(5) Synthesis Example 5: Synthesis of Compound M3d

[0842] ##STR00236##

[0843] Under nitrogen atmosphere, 1,2-dimethoxyethane (70 mL) and water (35 mL) were added to a mixture of 2-chloro-4,6-bis(dibenzo[b,d]furan-3-yl)-1,3,5-triazine (4.48 g, 10.0 mmol), (phenyl-d5) boronic acid (1.65 g, 13.0 mmol), tetrakis(triphenylphosphine)palladium (577.8 mg, 0.500 mmol), and sodium carbonate (3.18 g, 30.0 mmol), and the resulting mixture was stirred at 80 degrees C. for six hours. After completion of the reaction, the solid was filtered out and recrystallized with toluene to obtain a compound M3d (3.60 g, a yield of 73%). The obtained compound was identified as the compound M3d by analysis of LC-MS.

(6) Synthesis Example 6: Synthesis of Compound TADF2

(6-1) Synthesis of Intermediate E

[0844] ##STR00237##

[0845] Under nitrogen atmosphere, a mixture of 9H-carbazole-1,2,3,4,5,6,7,8-d8 (17.5 g, 100 mmol), tetrafluoroisophthalonitrile (8.00 g. 40.0 mmol), N,N-diisopropylethylamine (19.4 g, 150 mmol), and N,N-dimethylformamide (200 mL) was stirred at 60 degrees C. for four hours. After completion of the reaction, water was added thereto, and the solid was filtered out and purified by silica-gel column chromatography to obtain an intermediate E (6.13 g a yield of 30%).

(6-2) Synthesis of Compound TADF2

[0846] ##STR00238##

[0847] Under nitrogen atmosphere, a mixture of 12H-benzofuro[3,2-a]carbazole (1.93 g, 7.50 mmol), sodium hydride (0.180 g, 7.50 mmol), and tetrahydrofuran (40 mL) was stirred at room temperature (25 degrees C.) for 30 minutes. The intermediate E (1.53 g, 3.00 mmol) was added thereto, and the resulting mixture was stirred at room temperature (25 degrees C.) for two hours. After completion of the reaction, water was added thereto, and the solid was filtered out and purified by silica-gel column chromatography to obtain a compound TADF2 (2.22 g, a yield of 75%). The obtained compound was identified as the compound TADF2 by analysis of LC-MS.

EXPLANATION OF CODES

[0848] 1 . . . organic EL device, 2 . . . substrate, 3 . . . anode, 4 . . . cathode, 5 . . . emitting layer, 6 . . . hole injecting layer, 7 . . . hole transporting layer, 8 . . . electron transporting layer, 9 . . . electron injecting layer