ORGANIC ELECTROLUMINESCENT COMPOUND, A PLURALITY OF HOST MATERIALS AND ORGANIC ELECTROLUMINESCENT DEVICE COMPRISING THE SAME

Abstract

The present disclosure relates to an organic electroluminescent compound, a plurality of host materials comprising at least one first host compound and at least one second host compound, and an organic electroluminescent device comprising the same. An organic electroluminescent device with improved driving voltage, luminous efficiency and/or lifespan properties can be provided by comprising the organic electroluminescent compound or the specific combination of compounds according to the present disclosure as a host material.

Claims

1. A plurality of host materials comprising at least one first host compound and at least one second host compound, wherein the first host compound is represented by the following formula 1, and the second host compound is represented by the following formula 2: ##STR00124## in formula 1, X.sub.1, and Y.sub.1, each independently represent —N═, —NR.sub.11, —O— or —S—, with a proviso that any one of X.sub.1, and Y.sub.1, represents —N═, and the other of X.sub.1, and Y.sub.1, represents —NR.sub.11—, —O— or —S—; R.sub.1 represents a substituted or unsubstituted (C6-C30)aryl, or a substituted or unsubstituted (3- to 30-membered)heteroaryl; R.sub.2 to R.sub.4 and R.sub.11 each independently represent hydrogen, deuterium, a halogen, a cyano, a substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C6-C30)aryl, a substituted or unsubstituted (3- to 30-membered)heteroaryl, a substituted or unsubstituted (C3-C30)cycloalkyl, a substituted or unsubstituted (C1-C30)alkoxy, a substituted or unsubstituted tri(C1-C30)alkylsilyl, a substituted or unsubstituted di(C1-C30)alkyl(C6-C30)arylsilyl, a substituted or unsubstituted (C1-C30)alkyldi(C6-C30)arylsilyl, a substituted or unsubstituted tri(C6-C30)arylsilyl, a substituted or unsubstituted fused ring group of a (C3-C30) aliphatic ring(s) and a (C6-C30) aromatic ring(s), or -L.sub.2-N(Ar.sub.1)(Ar.sub.2); or may be linked to an adjacent substituent(s) to form a ring(s); R.sub.5 represents a substituted or unsubstituted (C6-C30)aryl, or a substituted or unsubstituted (3- to 30-membered)heteroaryl; R.sub.6 each independently represents hydrogen, deuterium, a halogen, a cyano, a substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C6-C30)aryl, a substituted or unsubstituted (3- to 30-membered)heteroaryl, a substituted or unsubstituted (C3-C30)cycloalkyl, a substituted or unsubstituted (C1-C30)alkoxy, a substituted or unsubstituted tri(C1-C30)alkylsilyl, a substituted or unsubstituted di(C1-C30)alkyl(C6-C30)arylsilyl, a substituted or unsubstituted (C1-C30)alkyldi(C6-C30)arylsilyl, a substituted or unsubstituted tri(C6-C30)arylsilyl, a substituted or unsubstituted fused ring group of a (C3-C30) aliphatic ring(s) and a (C6-C30) aromatic ring(s), or -L.sub.2-N(Ar.sub.1)(Ar.sub.2); L.sub.1 and L.sub.2 each independently represent a single bond, a substituted or unsubstituted (C6-C30)arylene, or a substituted or unsubstituted (3- to 30-membered)heteroarylene; Ar.sub.1 and Ar.sub.2 each independently represent hydrogen, a substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C2-C30)alkenyl, a substituted or unsubstituted fused ring group of a (C3-C30) aliphatic ring(s) and a (C6-C30) aromatic ring(s), a substituted or unsubstituted (C6-C30)aryl, or a substituted or unsubstituted (3- to 30-membered)heteroaryl; and n represents an integer of 0 to 3, a represents an integer of 1 to 5, d represents an integer of 1 to 4, and b and c each independently represent an integer of 1 or 2, where if a to d are an integer of 2 or more, each of R.sub.2 to each of R.sub.4, and each of R.sub.6 may be the same as or different from each other; ##STR00125## in formula 2, X.sub.2 represents —O— or —S—; R.sub.21 and R.sub.22 each independently represent hydrogen, deuterium, or a substituted or unsubstituted (C6-C30)aryl; Ar.sub.21 represents a substituted or unsubstituted naphthyl, a substituted or unsubstituted dibenzofuranyl, a substituted or unsubstituted dibenzothiophenyl, or a substituted or unsubstituted terphenyl; Ar.sub.22 represents a substituted or unsubstituted phenyl, a substituted or unsubstituted biphenyl, a substituted or unsubstituted naphthyl, or a substituted or unsubstituted terphenyl; and a′ represents an integer of 1 to 3, and b′ represents an integer of 1 to 4, where if a′ and b′ represent an integer of 2 or more, each of R.sub.21 and each of R.sub.22 may be the same as or different from each other, the substituent(s) of the substituted aryl, the substituted phenyl, the substituted biphenyl, the substituted terphenyl, the substituted naphthyl, the substituted dibenzofuranyl, and the substituted dibenzothiophenyl in formula 2 are each independently at least one of deuterium and a (C6-C30) aryl.

2. The plurality of host materials according to claim 1, wherein the substituent(s) of the substituted alkyl, the substituted alkenyl, the substituted aryl, the substituted arylene, the substituted heteroaryl, the substituted heteroarylene, the substituted cycloalkyl, the substituted alkoxy, the substituted trialkylsilyl, the substituted dialkylarylsilyl, the substituted alkyldiarylsilyl, the substituted triarylsilyl, and the substituted fused ring group of an aliphatic ring(s) and an aromatic ring(s) in formula 1 each independently are at least one selected from the group consisting of deuterium; a halogen; a cyano; a carboxyl; a nitro; a hydroxyl; a phosphine oxide; a (C1-C30)alkyl; a halo(C1-C30)alkyl; a (C2-C30)alkenyl; a (C2-C30)alkynyl; a (C1-C30)alkoxy; a (C1-C30)alkylthio; a (C3-C30)cycloalkyl; a (C3-C30)cycloalkenyl; a (3- to 7-membered)heterocycloalkyl; a (C6-C30)aryloxy; a (C6-C30)arylthio; a (3- to 30-membered)heteroaryl; a (C6-C30)aryl unsubstituted or substituted with at least one of deuterium and a (C6-C30)aryl(s); a tri(C1-C30)alkylsilyl(s); a tri(C6-C30)arylsilyl(s); a di(C1-C30)alkyl(C6-C30)arylsilyl; a (C1-C30)alkyldi(C6-C30)arylsilyl; a fused ring group of a (C3-C30) aliphatic ring(s) and a (C6-C30) aromatic ring(s); an amino; a mono- or di- (C1-C30)alkylamino; a mono- or di- (C2-C30)alkenylamino; a (C1-C30)alkyl(C2-C30)alkenylamino; a mono- or di- (C6-C30)arylamino; a (C1-C30)alkyl(C6-C30)arylamino; a mono- or di- (3- to 30-membered)heteroarylamino; a (C1-C30)alkyl(3- to 30-membered)heteroarylamino; a (C2-C30)alkenyl(C6-C30)arylamino; a (C2-C30)alkenyl(3- to 30-membered)heteroarylamino; a (C6-C30)aryl(3- to 30-membered)heteroarylamino; a (C1-C30)alkylcarbonyl; a (C1-C30)alkoxycarbonyl; a (C6-C30)arylcarbonyl; a (C6-C30)arylphosphine; a di(C6-C30)arylboronyl; a di(C1-C30)alkylboronyl; a (C1-C30)alkyl(C6-C30)arylboronyl; a (C6-C30)aryl(C1-C30)alkyl; and a (C1-C30)alkyl(C6-C30)aryl.

3. The plurality of host materials according to claim 1, wherein formula 1 is represented by the following formula 1-1: ##STR00126## in formula 1-1, d represents an integer of 1 to 3, where if d is an integer of 2 or more, each of R.sub.4 may be the same as or different from each other; and X.sub.1, Y.sub.1, R.sub.1, to R.sub.6, L.sub.1, n, and a to c are as defined in claim 1.

4. The plurality of host materials according to claim 1, wherein formula 1 is represented by at least one of the following formulas 1-1-1 to 1-1-4: ##STR00127## in formulas 1-1-1 to 1-1-4, d represents an integer of 1 to 3, where if d is an integer of 2 or more, each of R.sub.4 may be the same as or different from each other; and X.sub.1, Y.sub.1, R.sub.1, to R.sub.6, L.sub.1, n, and a to c are as defined in claim 1.

5. The plurality of host materials according to claim 1, wherein R.sub.5 is a substituted or unsubstituted phenyl, a substituted or unsubstituted naphthyl, a substituted or unsubstituted biphenyl, a substituted or unsubstituted terphenyl, a substituted or unsubstituted phenanthrenyl, a substituted or unsubstituted anthracenyl, a substituted or unsubstituted fluorenyl, a substituted or unsubstituted benzofluorenyl, a substituted or unsubstituted triphenylenyl, a substituted or unsubstituted spirobifluorenyl, a substituted or unsubstituted carbazolyl, a substituted or unsubstituted dibenzothiophenyl, a substituted or unsubstituted benzothiophenyl, a substituted or unsubstituted dibenzofuranyl, or a substituted or unsubstituted benzofuranyl.

6. The plurality of host materials according to claim 1, wherein formula 2 is represented by at least one of the following formulas 2-1 to 2-4: ##STR00128## in formulas 2-1 to 2-4, X.sub.2, Ar.sub.21, Ar.sub.22, R.sub.21, R.sub.22, a′, and b′ are as defined in claim 1.

7. The plurality of host materials according to claim 1, wherein the compound represented by formula 1 is at least one selected from the following compounds: ##STR00129## ##STR00130## ##STR00131## ##STR00132## ##STR00133##

8. The plurality of host materials according to claim 1, wherein the compound represented by formula 2 is at least one selected from the following compounds: ##STR00134## ##STR00135## ##STR00136## ##STR00137## ##STR00138## ##STR00139## ##STR00140## ##STR00141## ##STR00142## ##STR00143## ##STR00144## ##STR00145## ##STR00146## ##STR00147## ##STR00148## ##STR00149## ##STR00150## ##STR00151## ##STR00152## ##STR00153## ##STR00154##

9. An organic electroluminescent device comprising an anode, a cathode, and at least one light-emitting layer between the anode and the cathode, wherein the at least one light-emitting layer comprises the plurality of host materials according to claim 1.

10. An organic electroluminescent compound represented by the following formula 21: ##STR00155## in formula 21, Ar.sub.21 represents a naphthyl unsubstituted or substituted with deuterium, a phenylnaphthyl unsubstituted or substituted with deuterium, a naphthylphenyl unsubstituted or substituted with deuterium, or a terphenyl unsubstituted or substituted with deuterium; Ar.sub.22 represents a binaphthyl unsubstituted or substituted with deuterium; R.sub.21 and R.sub.22 each independently represent hydrogen or deuterium; and a′ represents an integer of 1 to 3, and b′ represents an integer of 1 to 4, where if a′ and b′ represent an integer of 2 or more, each of R.sub.21 and each of R.sub.22 may be the same as or different from each other.

11. The organic electroluminescent compound according to claim 10, wherein formula 21 is represented by the following formula 21-1: ##STR00156## in formula 21-1, Ar.sub.21, Ar.sub.22, R.sub.21, R.sub.22, a′, and b′ are as defined in claim 10.

12. The organic electroluminescent compound according to claim 10, wherein Ar.sub.22 is represented by one of the following formulas A-1 and A-2: ##STR00157## ##STR00158## in formulas A-1 and A-2, the hydrogen of the naphthalenes may be substituted with deuterium.

13. The organic electroluminescent compound according to claim 10, wherein the organic electroluminescent compound represented by formula 21 is selected from the following compounds: ##STR00159## ##STR00160## ##STR00161## ##STR00162## ##STR00163## ##STR00164##

14. An organic electroluminescent device comprising the organic electroluminescent compound according to claim 10.

15. An organic electroluminescent compound selected from the following compounds: ##STR00165## ##STR00166## ##STR00167##

16. An organic electroluminescent device comprising the organic electroluminescent compound according to claim 15.

Description

EXAMPLE 1: PREPARATION OF COMPOUND H1-17

[0107] ##STR00087##

[0108] Compound 1-1 (91.5 g, 222 mmol), compound 1-2 (70 g, 162.9 mmol), Pd(OAc).sub.2 (560 mg, 0.0025 mmol), X-Phos (2-dicyclophosphino-2′,4′,6′-triisopropylbiphenyl) (1.01 g, 0.002 mmol), NaOtBu (30.6 g, 318.4 mmol) and 2500 mL of toluene were added into a flask followed by stirring for 48 hours at 95° C. The mixture was cooled to room temperature, and the organic layer was extracted with ethyl acetate. The remaining moisture in the extracted organic layer was removed with magnesium sulfate. Thereafter, the organic layer was dried, and separated by column chromatography to obtain compound H1-17 (34 g, yield: 30%).

TABLE-US-00001 MW M.P. H1-17 704.83 200.5° C.

EXAMPLE 2: PREPARATION OF COMPOUND H1-16

[0109] ##STR00088##

[0110] Compound 2-1 (15 g, 36.4 mmol), compound 1-2 (10.9 g, 33.1 mmol), Pd.sub.2(dba).sub.3 (1.56 g, 1.7 mmol), S-Phos (2-dicyclophosphino-2′,6′-dimethoxybiphenyl) (1.35 g, 3.31 mmol), NaOtBu (6.36 g, 66.2 mmol) and 170 mL of xylene were added into a flask followed by stirring for 2 hours at 130° C. The mixture was cooled to room temperature, and the organic layer was extracted with ethyl acetate. The remaining moisture in the extracted organic layer was removed with magnesium sulfate. Thereafter, the organic layer was dried, and separated by column chromatography to obtain compound H1-16 (4.3 g, yield: 18%).

TABLE-US-00002 MW M.P. H1-16 704.83 230° C.

EXAMPLE 3: PREPARATION OF COMPOUND H2-1

[0111] ##STR00089##

1) Synthesis of Compound 3-1

[0112] 2,6-dibromonaphthalene (20 g, 70 mmol), phenylboronic acid (9 g, 73.4 mmol), K.sub.2CO.sub.3 (24 g, 175 mmol), Pd(PPh.sub.3).sub.4 (4 g, 3.5 mmol), 350 mL of toluene, 170 mL of H.sub.2O, and 170 mL of ethanol were added into a flask followed by refluxing for 1 hour at 130° C. After completion of the reaction, the organic layer was extracted with ethyl acetate, and the remaining moisture was removed with magnesium sulfate. Thereafter, the organic layer was dried, and separated by column chromatography to obtain compound 3-1 (13 g, yield: 67%).

2) Synthesis of Compound 3-2

[0113] Compound 3-1 (13 g, 45.9 mmol), 4,4,4′,4′,5,5,5′,5′-octamethyl-2,2′-bi(1,3,2-dioxaborolane) (17.5 g, 68.8 mmol), KOAc (11.3 g, 114.75 mmol), PdCl.sub.2(PPh.sub.3).sub.2 (3.2 g, 4.59 mmol), and 230 mL of 1,4-dioxane were added into a flask followed by refluxing for 2 hours at 150° C. After completion of the reaction, the organic layer was extracted with ethyl acetate, and the remaining moisture was removed with magnesium sulfate. Thereafter, the organic layer was dried, and separated by column chromatography to obtain compound 3-2 (9 g, yield: 59.3%).

3) Synthesis of Compound H2-1

[0114] Compound 3-2 (6.4 g, 19.16 mmol), compound 3-3 (6.5 g, 15.96 mmol), K.sub.2CO.sub.3 (5.5 g, 39.9 mmol), Pd(PPh.sub.3).sub.4 (922 mg, 0.798 mmol), 80 mL of toluene, 40 mL of ethanol, and 40 mL of H.sub.2O were added into a flask followed by refluxing for 2 hours at 130° C. After completion of the reaction, the organic layer was extracted with ethyl acetate, and the remaining moisture was removed with magnesium sulfate. Thereafter, the organic layer was dried, and separated by column chromatography to obtain compound H2-1 (4.9 g, yield: 53.3%).

TABLE-US-00003 MW M.P. H2-1 575.20 242.5° C.

EXAMPLE 4: PREPARATION OF COMPOUND H2-3

[0115] ##STR00090##

1) Synthesis of Compound 3-3

[0116] 2,4-dichloro-6-(naphthalen-2-yl)-1,3,5-triazine (58 g, 212 mmol), dibenzo[b,d]furan-1-yl boronic acid (30 g, 141 mmol), Na.sub.2CO.sub.3 (45 g, 424 mmol), Pd(PPh.sub.3).sub.4 (4.9 g, 7.05 mmol), 1.4 L of toluene and 352 mL of H.sub.2O were added into a flask followed by refluxing for 18 hours at 100° C. After completion of the reaction, the organic layer was extracted with ethyl acetate, and the remaining moisture was removed with magnesium sulfate. Thereafter, the organic layer was dried, and separated by column chromatography to obtain compound 3-3 (30 g, yield: 52%).

2) Synthesis of Compound H2-3

[0117] Compound 3-3 (6 g, 14.7 mmol), 4-(naphthalen-2-yl)-phenyl boronic acid (5.8 g, 17.64 mmol), K.sub.2CO.sub.3 (5.0 g, 36.75 mmol), Pd(PPh.sub.3).sub.4 (0.85 mg, 0.73 mmol), 70 mL of toluene, 35 mL of ethanol, and 35 mL of H.sub.2O were added into a flask followed by refluxing for 4 hours at 130° C. After completion of the reaction, the organic layer was extracted with ethyl acetate, and the remaining moisture was removed with magnesium sulfate. Thereafter, the organic layer was dried, and separated by column chromatography to obtain compound H2-3 (4.9 g, yield: 58%).

TABLE-US-00004 MW M.P. H2-3 575.20 192.9° C.

EXAMPLE 5: PREPARATION OF COMPOUND H2-39

[0118] ##STR00091##

1) Synthesis of Compound 2

[0119] Compound 1 (5 g, 12.2 mmol), 3-chloronaphthalen-2-yl boronic acid (3 g, 14.7 mmol), Pd(PPh.sub.3).sub.4 (704 mg, 0.61 mmol), K.sub.2CO.sub.3 (4.2 g, 30.2 mmol), 60 mL of toluene, 30 mL of ethanol, and 30 mL of H.sub.2O were added into a flask followed by stirring for 1 hour at 130° C. The mixture was cooled to room temperature, and the organic layer was extracted with ethyl acetate. The remaining moisture in the extracted organic layer was removed with magnesium sulfate. Thereafter, the organic layer was dried, and separated by column chromatography to obtain compound 2 (6 g, yield: 92%).

2) Synthesis of Compound H2-39

[0120] Compound 2 (4 g, 7.48 mmol), phenylboronic acid (1.1 g, 8.23 mmol), Pd.sub.2(dba).sub.3 (340 mg, 0.374 mmol), S-Phos (246 mg, 0.598 mmol), K.sub.3PO.sub.4 (3.97 g, 18.7 mmol), and 70 mL of xylene were added into a flask followed by stirring under reflux for 12 hours at 130° C. The mixture was cooled to room temperature, and the organic layer was extracted with ethyl acetate. The remaining moisture in the extracted organic layer was removed with magnesium sulfate. Thereafter, the organic layer was dried, and separated by column chromatography to obtain compound H2-39 (1.4 g, yield: 32.5%).

TABLE-US-00005 MW M.P. H2-39 575.20 216.8° C.

EXAMPLE 6: PREPARATION OF COMPOUND H2-41

[0121] ##STR00092##

[0122] Compound 1 (8.2 g, 24.8 mmol), 4,4,5,5-tetramethyl-2-(3-phenylnaphthalen-1-yl)-1,3,2-dioxaborolane (12 g, 29.8 mmol), Pd(PPh.sub.3).sub.4 (1.4 mg, 1.24 mmol), K.sub.2CO.sub.3 (8.6 g, 62 mmol), 120 mL of toluene, 60 mL of ethanol, and 60 mL of H.sub.2O were added into a flask followed by stirring for 1 hour at 130° C. The mixture was cooled to room temperature, and the organic layer was extracted with ethyl acetate. The remaining moisture in the extracted organic layer was removed with magnesium sulfate. Thereafter, the organic layer was dried, and separated by column chromatography to obtain compound H2-41 (4.1 g, yield: 28.7%).

TABLE-US-00006 MW M.P. H2-41 575.20 159.6° C.

EXAMPLE 7: PREPARATION OF COMPOUND H2-44

[0123] ##STR00093##

[0124] Compound 7-1 (8.5 g, 15.91 mol), phenylboronic acid (2.3 g, 19.10 mmol), K.sub.3PO.sub.4 (8.4 g, 39.77 mmol), S-Phos (653 mg, 1.591 mmol), Pd.sub.2(dba).sub.3 (1.4 g, 1.591 mmol), and 100 mL of toluene were added into a flask followed by stirring under reflux for 12 hours at 130° C. After completion of the reaction, the organic layer was extracted with ethyl acetate, and the remaining moisture was removed with magnesium sulfate. Thereafter, the organic layer was dried, and separated by column chromatography to obtain compound H2-44 (4.0 g, yield: 43%).

TABLE-US-00007 MW M.P. H2-44 575.67 231.9° C.

EXAMPLE 8: PREPARATION OF COMPOUND H2-42

[0125] ##STR00094##

1) Synthesis of Compound 8-3

[0126] Compound 8-1 (21.0 g, 72.77 mmol), compound 8-2 (35.6 g, 87.32 mmol), Pd(pph.sub.3).sub.4 (4.2 g, 3.64 mmol), and K.sub.2CO.sub.3 (138.21 g, 149.54 mmol) were dissolved in 365 mL of toluene, 90 mL of ethanol, and 90 mL of H.sub.2O and stirred under reflux for 2 hours. The mixture was cooled to room temperature. H.sub.2O was added to the reactant in which the solid was formed, and the mixture was stirred for 30 minutes and filtered. The filtrate was recrystallized to obtain compound 8-3 (33.1 g, yield: 85.3%).

2) Synthesis of Compound H2-42

[0127] Compound 8-3 (10.0 g, 18.73 mmol), phenylboronic acid (9.2 g, 74.90 mmol), Pd.sub.2(dba).sub.3 (1.8 g, 1.88 mmol), S-Phos (0.8 g, 3.74 mmol), and K.sub.3PO.sub.4 (20.0 g, 93.64 mmol) were dissolved in 150 mL of o-xylene and stirred under reflux for 2 hours 30 minutes. The mixture was cooled to room temperature, filtered through celite, separated by column chromatography, and recrystallized to obtain compound H2-42 (3.0 g, yield: 28.0%).

TABLE-US-00008 MW M.P. H2-42 575.66 227° C.

EXAMPLE 9: PREPARATION OF COMPOUND H2-46

[0128] ##STR00095##

[0129] Compound 9-1 (15.2 g, 46.03 mmol), compound 9-2 (22.5 g, 55.23 mmol), Pd(pph.sub.3).sub.4 (2.7 g, 2.30 mmol), and K.sub.2CO.sub.3 (12.7 g, 92.06 mmol) were dissolved in 230 mL of toluene, 60 mL of ethanol, and 60 mL of H.sub.2O and stirred under reflux for 3 hours. The mixture was cooled to room temperature. H.sub.2O was added to the reactant in which solid was formed, and the mixture was stirred for 30 minutes, and then filtered. The filtrate was filtered through silica and then recrystallized to obtain compound H2-46 (19.6 g, yield: 73.9%).

TABLE-US-00009 MW M.P. H2-46 575.66 209° C.

EXAMPLE 10: PREPARATION OF COMPOUND H2-37

[0130] ##STR00096##

[0131] Compound 10-1 (4.6 g, 13.93 mmol), compound 10-2 (5.6 g, 13.93 mmol), Pd(pph.sub.3).sub.4 (0.8 g, 0.696 mmol), K.sub.2CO.sub.3 (5.7 g, 41.79 mmol), 20 mL of H.sub.2O, 20 mL of ethanol, and 80 mL of toluene were added into a flask followed by stirring under reflux for 2 hours. After completion of the reaction, the mixture was cooled to room temperature. Then, methanol was added dropwise to the mixture, and filtered. The filtrate was dissolved in o-xylene and filtered through silica to obtain compound H2-37 (3.9 g, yield: 48%).

TABLE-US-00010 MW M.P. H2-37 575.6 264.1° C.

EXAMPLE 11: PREPARATION OF COMPOUND H2-43

[0132] ##STR00097##

[0133] Compound 11-1 (4.4 g, 13.48 mmol), compound 11-2 (5 g, 12.25 mmol), Pd(pph.sub.3).sub.4 (0.7 g, 0.612 mmol), K.sub.2CO.sub.3 (5.1 g, 36.77 mmol), 20 mL of H.sub.2O, 20 mL of ethanol, and 80 mL of toluene were added into a flask followed by stirring under reflux for 2 hours. After completion of the reaction, the mixture was cooled to room temperature. Then, methanol was added dropwise to the mixture, and filtered. The filtrate was dissolved in o-xylene and filtered through silica to obtain compound H2-43 (4.6 g, yield: 65%).

TABLE-US-00011 MW M.P. H2-43 575.6 224.9° C.

EXAMPLE 12: PREPARATION OF COMPOUND H2-61

[0134] ##STR00098##

[0135] Compound 12-1 (10 g, 24.5 mmol), compound 12-2 (3 g, 14.7 mmol), Pd(PPh.sub.3).sub.4 (1.4 g, 1.225 mmol), K.sub.2CO.sub.3 (6.7 g, 49 mmol), 120 mL of toluene, 60 mL of ethanol, and 60 mL of H.sub.2O were added into a flask followed by stirring for 3 hours at 130° C. After completion of the reaction, the mixture was cooled to room temperature, and the organic layer was extracted with ethyl acetate. The remaining moisture in the extracted organic layer was removed with magnesium sulfate. Thereafter, the organic layer was dried, and separated by column chromatography to obtain compound H2-61 (13 g, yield: 84%).

TABLE-US-00012 MW M.P. H2-61 625.73 229.1° C.

EXAMPLE 13: PREPARATION OF COMPOUND H2-64

[0136] ##STR00099##

[0137] Compound 13-1 (10 g, 18.7 mmol), naphthalen-1-yl-boronic acid (6.5 g, 37.4 mmol), Pd.sub.2(dba).sub.3 (856 mg, 0.935 mmol), S-Phos (767 mg, 1.87 mmol), K.sub.3PO.sub.4 (9.9 g, 46.75 mmol), and 93.5 mL of xylene were added into a flask followed by stirring for 18 hours at 160° C. After completion of the reaction, the mixture was cooled to room temperature, and the organic layer was extracted with ethyl acetate. The remaining moisture in the extracted organic layer was removed with magnesium sulfate. Thereafter, the organic layer was dried, and separated by column chromatography to obtain compound H2-64 (4.4 g, yield: 37.6%).

TABLE-US-00013 MW M.P. H2-64 625.73 237.2° C.

DEVICE EXAMPLES 1 TO 6: PRODUCING OLEDS COMPRISING THE PLURALITY OF HOST MATERIALS ACCORDING TO THE PRESENT DISCLOSURE

[0138] An OLED according to the present disclosure was produced. First, a transparent electrode indium tin oxide (ITO) thin film (Ω/sq) on a glass substrate for an OLED (GEOMATEC CO., LTD., Japan) was subjected to an ultrasonic washing with acetone and isopropyl alcohol, sequentially, and then was stored in isopropyl alcohol. The ITO substrate was mounted on a substrate holder of a vacuum vapor deposition apparatus. Compound HI-1 shown in Table 7 was introduced into a cell of the vacuum vapor deposition apparatus, and compound HT-1 was introduced into another cell. The two materials were evaporated at different rates, and compound HI-1 was deposited in a doping amount of 3 wt % based to the total amount of compound HI-1 and compound HT-1 to form a hole injection layer with a thickness of 10 nm. Subsequently, compound HT-1 was deposited on the hole injection layer to form a first hole transport layer with a thickness of 80 nm. Next, compound HT-2 was introduced into another cell of the vacuum vapor deposition apparatus and was evaporated by applying an electric current to the cell, thereby depositing a second hole transport layer with a thickness of 60 nm on the first hole transport layer. After forming the hole injection layer and the hole transport layers, a light-emitting layer was deposited thereon as follows: Each of the first host compound and the second host compound shown in Tables 1 to 3 below were introduced into two cells of the vacuum vapor deposition apparatus as hosts, and compound D-39 was introduced into another cell as a dopant. The two host materials were evaporated at a rate of 1:1 and the dopant material was simultaneously evaporated at a different rate, and the dopant was deposited in a doping amount of 3 wt % based on the total amount of the hosts and dopant to form a light-emitting layer with a thickness of 40 nm on the second hole transport layer. Then, compound ETL-1 and compound EIL-1 were evaporated at a weight ratio of 50:50 as an electron transport material to form an electron transport layer having a thickness of 35 nm on the light-emitting layer. After depositing compound EIL-1 as an electron injection layer with a thickness of 2 nm on the electron transport layer, an AI cathode was deposited with a thickness of 80 nm on the electron injection layer by using another vacuum vapor deposition apparatus, thereby producing an OLED. All the materials used for producing the OLED were purified by vacuum sublimation at 10.sup.−6 torr.

COMPARATIVE EXAMPLES 1 TO 5: PRODUCING OLEDS COMPRISINQ A HOST COMBINATION NOT ACCORDING TO THE PRESENT DISCLOSURE

[0139] OLEDs were produced in the same manner as in Device Examples 1 to 6, except that the host compound shown in Tables 1 to 3 was used as the first host compound of the light-emitting layer.

[0140] The driving voltage, luminous efficiency, and light-emitting color at a luminance of 1,000 nit, and the time taken for luminance to reduce from 100% to 95% at a luminance of 10,000 nit (lifespan: T95) of the organic electroluminescent devices of Device Examples 1 to 6 and Comparative Examples 1 to 5 produced as described above, are shown in the following Tables 1 to 3.

TABLE-US-00014 TABLE 1 Driving Luminous Light- First Host Second Host Voltage Efficiency Emitting Lifespan Compound Compound (V) (cd/A) Color T95(hr) Device H1-16 H2-1 2.9 32.7 Red 104 Example 1 Device H1-17 H2-1 2.9 32.8 Red 96 Example 2 Comparative Ref-1 H2-1 3.0 30.9 Red 74 Example 1 Comparative Ref-2 H2-1 3.0 28.7 Red 64 Example 2

TABLE-US-00015 TABLE 2 Driving Luminous Light- First Host Second Host Voltage Efficiency Emitting Lifespan Compound Compound (V) (cd/A) Color T95(hr) Device H1-16 H2-2 3.0 33.2 Red 42 Example 3 Device H1-17 H2-2 2.9 33.0 Red 46 Example 4 Comparative Ref-1 H2-2 3.0 30.7 Red 18 Example 3 Comparative Ref-2 H2-2 3.0 29.3 Red 23 Example 4

TABLE-US-00016 TABLE 3 Driving Luminous Light- First Host Second Host Voltage Efficiency Emitting Lifespan Compound Compound (V) (cd/A) Color T95(hr) Device H1-16 H2-4 3.0 33.0 Red 82 Example 5 Device H1-17 H2-4 2.9 32.8 Red 85 Example 6 Comparative Ref-1 H2-4 3.0 31.8 Red 46 Example 5

[0141] From Tables 1 to 3 above, it can be confirmed that the OLEDs (Device Examples 1 to 6) comprising a specific combination of compounds according to the present disclosure as host materials, exhibit lower driving voltage and/or higher luminous efficiency, and significantly improved lifespan characteristics compared to the OLEDs (Comparative Examples 1 to 5) comprising a host combination not according to the present disclosure.

[0142] [Characteristic Analysis]

[0143] In order to support the theory of the combination of the host material and the electron transport zone according to the present disclosure, a Hole Only Device (HOD) was produced to confirm and compare the hole current characteristics in devices based on the properties of biphenyl and terphenyl in phenanthroxazole derivatives. The structure of the hole only device is as follows.

[0144] Hole Only Device (HOD) Example

[0145] An ITO substrate was mounted on a substrate holder of a vacuum vapor deposition apparatus. Compound HI-1 shown in Table 7 was introduced into a cell of the vacuum vapor deposition apparatus, and then the pressure in the chamber of the apparatus was controlled to 10.sup.−7 torr. Thereafter, an electric current was applied to the cell to evaporate the above-introduced material, thereby forming a hole injection layer having a thickness of 10 nm on the ITO substrate. Compound HI-1 was introduced into a cell of the vacuum vapor deposition apparatus, and compound HT-1 was introduced into another cell. The two materials were evaporated at different rates, and compound HI-1 was deposited in a doping amount of 3 wt % based to the total amount of compound HI-1 and compound HT-1 to form a first hole transport layer with a thickness of 10 nm. Next, compound HT-2 was introduced into another cell of the vacuum vapor deposition apparatus and was evaporated by applying an electric current to the cell, thereby depositing a second hole transport layer with a thickness of 10 nm on the first hole transport layer. After forming the hole injection layer and the hole transport layers, a light-emitting layer was deposited thereon as follows: The compound shown in Table 4 below was introduced into a cell of the vacuum vapor deposition apparatus as a host, and evaporated to form a light-emitting layer with a thickness of 40 nm on the second hole transport layer. Then, Compound HI-1 was introduced into a cell of the vacuum vapor deposition apparatus, and compound HT-1 was introduced into another cell. The two materials were evaporated at different rates, and compound HI-1 was deposited in a doping amount of 3 wt % based to the total amount of compound HI-1 and compound HT-1 to form a electron blocking layer with a thickness of 10 nm on the light-emitting layer. Then, an AI cathode was deposited with a thickness of 80 nm on the electron blocking layer by using another vacuum vapor deposition apparatus, thereby producing an OLED. All the materials used for producing the OLED were purified by vacuum sublimation at 10.sup.−7 torr.

[0146] Table 4 below shows current densities (mA/cm.sup.2) reaching a voltage of 2 V depending on the material of the light-emitting layer of the hole only device produced as described above.

TABLE-US-00017 TABLE 4 Llight-Emitting Current Density Layer (mA/cm.sup.2) Ref-1 11 H1-16 20

[0147] From Table 4 above, it can be confirmed that the hole only device comprising the compound according to the present disclosure, exhibits higher current density and faster hole current characteristics compared to the hole only device comprising the compound not according to the present disclosure. Upon comparing the HOMO energy levels of the compounds included in the second hole transport layer and the light-emitting layer in the Hole Only Device Example, the compound Ref-1 comprising a biphenyl group and the compound H1-16 comprising a terphenyl group have energy levels of −4.95 eV and −4.92 eV, respectively, and the compound HT-2 included in the second hole transport layer has an energy level of −4.88 eV. Therefore, without being limited by theory, it can be confirmed that the hole only device comprising the compound according to the present disclosure smoothly injects holes from the hole transport layer to the light-emitting layer. Accordingly, an organic electroluminescent device comprising the compound according to the present disclosure may exhibit low driving voltage, high luminous efficiency, and/or long lifespan characteristics.

DEVICE EXAMPLES 7 TO 12: PRODUCING OLEDS COMPRISING THE PLURALITY OF HOST MATERIALS ACCORDING TO THE PRESENT DISCLOSURE

[0148] OLEDs were produced in the same manner as in Device Examples 1 to 6, except that compound HT-3 and compound HT-4 were used instead of compound HT-1 and compound HT-2, respectively, and the compounds shown in Table 5 were used as the first host compound and the second host compound of the light-emitting layer.

[0149] The driving voltage, luminous efficiency, and light-emitting color at a luminance of 1,000 nit, and the time taken for luminance to reduce from 100% to 95% at a luminance of 10,000 nit (lifespan: T95) of the OLEDs of Device Examples 7 to 12 produced as described above, are shown in the following Table 5.

TABLE-US-00018 TABLE 5 Driving Luminous Light- First Host Second Host Voltage Efficiency Emitting Lifespan Compound Compound (V) (cd/A) Color T95(hr) Device H1-16 H2-39 3.3 36.1 Red 252 Example 7 Device H1-16 H2-41 2.9 32.4 Red 193 Example 8 Device H1-16 H2-44 2.9 32.9 Red 255 Example 9 Device H1-16 H2-42 3.0 35.4 Red 220 Example 10 Device H1-16 H2-64 3.1 35.5 Red 276 Example 11 Device H1-16 H2-61 3.0 32.3 Red 219 Example 12

DEVICE EXAMPLE 13: PRODUCING AN OLED COMPRISING THE SINGLE HOST MATERIAL ACCORDING TO THE PRESENT DISCLOSURE

[0150] An OLED was produced in the same manner as in Device Example 7, except that the host compound shown in Table 6 below was used alone as a host material of a light-emitting layer.

COMPARATIVE EXAMPLE 6: PRODUCING AN OLED COMPRISING A CONVENTIONAL HOST MATERIAL

[0151] An OLED was produced in the same manner as in Device Example 13, except that the host compound shown in Table 6 below was used as a host material of a light-emitting layer.

[0152] The luminous efficiency and light-emitting color at a luminance of 1,000 nit of the OLEDs of Device Example 13 and Comparative Example 6 produced as described above are shown in the following Table 6.

TABLE-US-00019 TABLE 6 Luminous Light- Single Host Efficiency Emitting Compound (cd/A) Color Device Example 13 H2-64 30.0 Red Comparative Example 6 H2-51 26.4 Red

[0153] From Table 6 above, it can be confirmed that the OLED comprising an organic electroluminescent compound according to the present disclosure as a single host material, exhibits higher luminous efficiency compared to the OLED comprising a conventional host material.

DEVICE EXAMPLE 14: PRODUCING AN OLED COMPRISING THE PLURALITY OF HOST MATERIALS ACCORDING TO THE PRESENT DISCLOSURE

[0154] An OLED was produced in the same manner as in Device Example 7, except that compound HT-5 was used instead of compound HT-4, and the compounds shown in Table 7 were used as the first host compound and the second host compound of the light-emitting layer.

COMPARATIVE EXAMPLE 7: PRODUCING AN OLED COMPRISING A CONVENTIONAL HOST MATERIAL

[0155] An OLED was produced in the same manner as in Device Example 14, except that the host compound shown in Table 7 below was used as a host material of a light-emitting layer.

[0156] The driving voltage, power efficiency, and light-emitting color at a luminance of 1,000 nit, and the time taken for luminance to reduce from 100% to 95% at a luminance of 10,000 nit (lifespan: T95) of the OLEDs of Device Example 14 and Comparative Example 7 produced as described above, are shown in the following Table 7.

TABLE-US-00020 TABLE 7 Driving Power Light- First Host Second Host Voltage Efficiency Emitting Lifespan Compound Compound (V) (Lm/W) Color T95(hr) Device H1-9 H2-2 2.8 39.1 Red 195 Example 14 Comparative Ref-2 H2-2 3.0 36.7 Red 135 Example 7

[0157] From Table 7 above, it can be confirmed that the OLED comprising the plurality of host materials according to the present disclosure, exhibits lower driving voltage, higher power efficiency, and excellent lifespan properties compared to the OLED comprising a conventional host material.

[0158] The compounds used in the Device Examples, Comparative Examples, and Hole Only Device Example are shown in Table 8 below.

TABLE-US-00021 TABLE 8 Hole Injection Layer/Hole Transport Layer/ Electron Blocking Layer [00100] HI-1 [00101] HT-1 [00102] HT-2 [00103] HT-3 [00104] HT-4 [00105] HT-5 Light-Emitting Layer [00106] H1-9 [00107] H1-16 [00108] H1-17 [00109] Ref-1 [00110] Ref-2 [00111] H2-1 [00112] H2-2 [00113] H2-4 [00114] H2-41 [00115] H2-39 [00116] H2-44 [00117] H2-42 [00118] H2-64 [00119] H2-61 [00120] H2-51 [00121] D-39 Electron Transport Layer/ Electron Injection Layer [00122] ETL-1 [00123] EIL-1