HETEROCYCLIC COMPOUND, ORGANIC LIGHT-EMITTING DEVICE INCLUDING THE SAME, AND ELECTRONIC APPARATUS INCLUDING THE ORGANIC LIGHT-EMITTING DEVICE

Abstract

Provided are a heterocyclic compound represented by Formula 1, an organic light-emitting device including the same, and an electronic apparatus including the organic light-emitting device:

##STR00001## wherein descriptions of Formula 1 are as defined in the present specification.

Claims

1. A heterocyclic compound represented by Formula 1: ##STR03241## wherein, in Formula 1, X.sub.11 and X.sub.12 are each independently a carbon atom, and are linked to each other via a single bond or a double bond, Y.sub.11 to Y.sub.16 are each independently a carbon atom, and any neighboring two of Y.sub.11 to Y.sub.16 are linked via a single bond or a double bond, and B.sub.11 is a group represented by Formula 1A: ##STR03242## wherein, in Formula 1A, Z.sub.11 to Z.sub.16 are each independently a carbon atom, and any neighboring two of Z.sub.11 to Z.sub.16 are linked via a single bond or a double bond, and W.sub.11 and W.sub.12 are each independently a carbon atom, are linked via a single bond or a double bond, and are *1 and *2 in Formula 1, in Formulae 1 and 1A, A.sub.11 and C.sub.11 to C.sub.14 are each independently a C.sub.5-C.sub.30 carbocyclic group or a C.sub.1-C.sub.30 heterocyclic group, R.sub.x is a group represented by one of Formulae 2-1 to 2-3, R.sub.y and R.sub.11 to R.sub.15 are each independently a group represented by one of Formulae 2-1 to 2-3, hydrogen, deuterium, —F, —Cl, —Br, —I, —SF.sub.5, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a substituted or unsubstituted C.sub.1-C.sub.60 alkyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkenyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkynyl group, a substituted or unsubstituted C.sub.1-C.sub.60 alkoxy group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenyl group, a substituted or unsubstituted C.sub.2-C.sub.10 heterocycloalkenyl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.7-C.sub.60 alkylaryl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryloxy group, a substituted or unsubstituted C.sub.6-C.sub.60 arylthio group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryl group, a substituted or unsubstituted C.sub.2-C.sub.60 heteroalkylaryl group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryloxy group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroarylthio group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q.sub.1)(Q.sub.2)(Q.sub.3), —C(Q.sub.1)(Q.sub.2)(Q.sub.3), —B(Q.sub.1)(Q.sub.2), —N(Q.sub.1)(Q.sub.2), —P(Q.sub.1)(Q.sub.2), —C(═O)(Q.sub.1), —S(═O)(Q.sub.1), —S(═O).sub.2(Q.sub.1), —P(═O)(Q.sub.1)(Q.sub.2), or —P(═S)(Q.sub.1)(Q.sub.2), b11 to b14 are each independently 0, 1, 2, 3, or 4, and b15 is 0, 1, or 2: ##STR03243## wherein, in Formulae 2-1 to 2-3, X.sub.21 is a single bond, O, S, N(R.sub.28), or C(R.sub.28)(R.sub.29), X.sub.22 is a single bond, O, S, N(R.sub.30), or C(R.sub.30)(R.sub.31), L.sub.21 to L.sub.23 are each independently a substituted or unsubstituted C.sub.5-C.sub.30 carbocyclic group or a substituted or unsubstituted C.sub.1-C.sub.30 heterocyclic group, a21 to a23 are each independently 0, 1, 2, 3, or 4, R.sub.21 and R.sub.22 are each independently a substituted or unsubstituted C.sub.1-C.sub.60 alkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenyl group, a substituted or unsubstituted C.sub.2-C.sub.10 heterocycloalkenyl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.7-C.sub.60 alkylaryl group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryl group, a substituted or unsubstituted C.sub.2-C.sub.60 heteroalkylaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, or a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, R.sub.23 to R.sub.31 are each independently hydrogen, deuterium, —F, —Cl, —Br, —I, —SF.sub.5, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a substituted or unsubstituted C.sub.1-C.sub.60 alkyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkenyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkynyl group, a substituted or unsubstituted C.sub.1-C.sub.60 alkoxy group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenyl group, a substituted or unsubstituted C.sub.2-C.sub.10 heterocycloalkenyl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.7-C.sub.60 alkylaryl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryloxy group, a substituted or unsubstituted C.sub.6-C.sub.60 arylthio group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryl group, a substituted or unsubstituted C.sub.2-C.sub.60 heteroalkylaryl group, a substituted or unsubstituted heteroaryloxy group, a substituted or unsubstituted heteroarylthio group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q.sub.1)(Q.sub.2)(Q.sub.3), —C(Q.sub.1)(Q.sub.2)(Q.sub.3), —B(Q.sub.1)(Q.sub.2), —N(Q.sub.1)(Q.sub.2), —P(Q.sub.1)(Q.sub.2), —C(═O)(Q.sub.1), —S(═O)(Q.sub.1), —S(═O).sub.2(Q.sub.1), —P(═O)(Q.sub.1)(Q.sub.2), or —P(═S)(Q.sub.1)(Q.sub.2), b23 to b26 are each independently 0, 1, 2, 3, or 4, Q.sub.1 to Q.sub.3 are each independently hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, a C.sub.1-C.sub.60 alkoxy group, a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.2-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.7-C.sub.60 alkylaryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a C.sub.2-C.sub.60 heteroalkylaryl group, a C.sub.1-C.sub.60 heteroaryloxy group, a C.sub.1-C.sub.60 heteroarylthio group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a C.sub.1-C.sub.60 alkyl group that is substituted with at least one deuterium, —F, a cyano group, a C.sub.1-C.sub.60 alkyl group, or a C.sub.6-C.sub.60 aryl group, and a C.sub.6-C.sub.60 aryl group that is substituted with at least one deuterium, —F, a cyano group, a C.sub.1-C.sub.60 alkyl group, a C.sub.6-C.sub.60 aryl group, or any combination thereof, and * indicates a binding site to a neighboring atom.

2. The heterocyclic compound of claim 1, wherein A.sub.11 and C.sub.11 to C.sub.14 are each independently a benzene group, a naphthalene group, a phenanthrene group, a furan group, a thiophene group, a pyrrole group, a cyclopentene group, a silole group, a germole group, a benzofuran group, a benzothiophene group, an indole group, an indene group, a benzosilole group, a benzogermole group, a dibenzofuran group, a dibenzothiophene group, a carbazole group, a fluorene group, a dibenzosilole group, a dibenzogermole group, a pyridine group, a pyrimidine group, or a pyridazine group.

3. The heterocyclic compound of claim 1, wherein A.sub.11 is a group represented by Formula 3-1: ##STR03244## wherein, in Formula 3-1, X.sub.11 to X.sub.16 are each independently a nitrogen atom or a carbon atom, and any neighboring two of X.sub.13 to X.sub.16 are each *1 and *2 in Formula 1, R.sub.15 is defined the same as R.sub.11 in Formula 1, and b15 is 0, 1, or 2.

4. The heterocyclic compound of claim 1, wherein A.sub.11 is a group represented by one of Formulae 3-11 to 3-16: ##STR03245## wherein, in Formulae 3-11 to 3-16, X.sub.11 to X.sub.16 are each independently a nitrogen atom or a carbon atom, W.sub.11 and W.sub.12 are each independently a nitrogen atom or a carbon atom, and R.sub.15a and R.sub.15b are each independently defined the same as Ru in Formula 1.

5. The heterocyclic compound of claim 1, wherein R.sub.x and R.sub.y in Formula 1 are each independently a group represented by one of Formulae 2-1 to 2-3.

6. The heterocyclic compound of claim 1, wherein the heterocyclic compound is represented by Formulae 11 or 12: ##STR03246## wherein, in Formulae 11 and 12, X.sub.11, X.sub.12, Y.sub.11 to Y.sub.16, Z.sub.11 to Z.sub.16, W.sub.11, W.sub.12, A.sub.11, C.sub.11 to C.sub.14, R.sub.x, R.sub.y, R.sub.11 to R.sub.14, and b.sub.11 to b.sub.14 are defined the same as those in Formulae 1 and 1A, respectively.

7. The heterocyclic compound of claim 6, wherein A.sub.11 is a group represented by one of Formulae 3-11 to 3-16: ##STR03247## wherein, in Formulae 3-11 to 3-16, X.sub.11 to X.sub.16 are each independently a nitrogen atom or a carbon atom, W.sub.11 and W.sub.12 are each independently a nitrogen atom or a carbon atom, and R.sub.15a and R.sub.15b are each independently defined the same as R.sub.11 in Formula 1.

8. The heterocyclic compound of claim 1, wherein the heterocyclic compound is represented by Formulae 11-1 or 12-1: ##STR03248## wherein, in Formulae 11-1 and 12-1, X.sub.11, X.sub.12, W.sub.11, W.sub.12, A.sub.11, R.sub.x, and R.sub.y are defined the same as those in Formulae 1 and 1A, respectively, R.sub.11a to R.sub.11c, R.sub.12a to R.sub.12c, R.sub.13a to R.sub.13c, and R.sub.14a to R.sub.14c are each defined the same as R.sub.11 in Formula 1, and any neighboring two of R.sub.11a to R.sub.11c, R.sub.12a to R.sub.12c, R.sub.13a to R.sub.13c, and R.sub.14a to R.sub.14c are optionally combined with each other to form a ring.

9. The heterocyclic compound of claim 8, wherein A.sub.11 is a group represented by one of Formulae 3-11 to 3-16: ##STR03249## wherein, in Formulae 3-11 to 3-16, X.sub.11 to X.sub.16 are each independently a nitrogen atom or a carbon atom, W.sub.11 and W.sub.12 are each independently a nitrogen atom or a carbon atom, and R.sub.15a and R.sub.15b are each independently defined the same as R.sub.11 in Formula 1.

10. The heterocyclic compound of claim 1, wherein the heterocyclic compound is a compound of Group C: ##STR03250## ##STR03251## ##STR03252## ##STR03253## ##STR03254## ##STR03255## ##STR03256## ##STR03257## ##STR03258## ##STR03259## ##STR03260## ##STR03261## ##STR03262## ##STR03263## ##STR03264## ##STR03265## ##STR03266## ##STR03267## ##STR03268## ##STR03269## ##STR03270## ##STR03271## ##STR03272## ##STR03273## ##STR03274## ##STR03275## ##STR03276## ##STR03277## ##STR03278## ##STR03279## ##STR03280## ##STR03281## ##STR03282## ##STR03283## ##STR03284## ##STR03285## ##STR03286## ##STR03287## ##STR03288## ##STR03289## ##STR03290## ##STR03291## ##STR03292## ##STR03293## ##STR03294## ##STR03295## ##STR03296## ##STR03297## ##STR03298## ##STR03299## ##STR03300## ##STR03301## ##STR03302## ##STR03303## ##STR03304## ##STR03305## ##STR03306## ##STR03307## ##STR03308## ##STR03309## ##STR03310## ##STR03311## ##STR03312## ##STR03313## ##STR03314## ##STR03315## ##STR03316## ##STR03317## ##STR03318## ##STR03319## ##STR03320## ##STR03321## ##STR03322## ##STR03323## ##STR03324## ##STR03325## ##STR03326## ##STR03327## ##STR03328## ##STR03329## ##STR03330## ##STR03331## ##STR03332## ##STR03333## ##STR03334## ##STR03335## ##STR03336## ##STR03337## ##STR03338## ##STR03339## ##STR03340## ##STR03341## ##STR03342## ##STR03343## ##STR03344## ##STR03345## ##STR03346## ##STR03347## ##STR03348## ##STR03349## ##STR03350## ##STR03351## ##STR03352## ##STR03353## ##STR03354## ##STR03355## ##STR03356## ##STR03357## ##STR03358## ##STR03359## ##STR03360## ##STR03361## ##STR03362## ##STR03363## ##STR03364## ##STR03365## ##STR03366## ##STR03367## ##STR03368## ##STR03369## ##STR03370## ##STR03371## ##STR03372## ##STR03373## ##STR03374## ##STR03375## ##STR03376## ##STR03377## ##STR03378## ##STR03379## ##STR03380## ##STR03381## ##STR03382## ##STR03383## ##STR03384## ##STR03385## ##STR03386## ##STR03387## ##STR03388## ##STR03389## ##STR03390## ##STR03391## ##STR03392## ##STR03393## ##STR03394## ##STR03395## ##STR03396## ##STR03397## ##STR03398## ##STR03399## ##STR03400## ##STR03401## ##STR03402## ##STR03403## ##STR03404## ##STR03405## ##STR03406## ##STR03407## ##STR03408## ##STR03409## ##STR03410## ##STR03411## ##STR03412## ##STR03413## ##STR03414## ##STR03415## ##STR03416## ##STR03417## ##STR03418## ##STR03419## ##STR03420## ##STR03421## ##STR03422## ##STR03423## ##STR03424## ##STR03425## ##STR03426## ##STR03427## ##STR03428## ##STR03429## ##STR03430## ##STR03431## ##STR03432## ##STR03433## ##STR03434## ##STR03435## ##STR03436## ##STR03437## ##STR03438## ##STR03439## ##STR03440## ##STR03441## ##STR03442## ##STR03443## ##STR03444## ##STR03445## ##STR03446## ##STR03447## ##STR03448## ##STR03449## ##STR03450## ##STR03451## ##STR03452## ##STR03453## ##STR03454## ##STR03455## ##STR03456## ##STR03457## ##STR03458## ##STR03459## ##STR03460## ##STR03461## ##STR03462## ##STR03463## ##STR03464## ##STR03465## ##STR03466## ##STR03467## ##STR03468## ##STR03469## ##STR03470## ##STR03471## ##STR03472## ##STR03473## ##STR03474## ##STR03475## ##STR03476## ##STR03477## ##STR03478## ##STR03479## ##STR03480## ##STR03481## ##STR03482## ##STR03483## ##STR03484## ##STR03485## ##STR03486## ##STR03487## ##STR03488## ##STR03489## ##STR03490## ##STR03491## ##STR03492## ##STR03493## ##STR03494## ##STR03495## ##STR03496## ##STR03497## ##STR03498## ##STR03499## ##STR03500## ##STR03501## ##STR03502## ##STR03503## ##STR03504## ##STR03505## ##STR03506## ##STR03507## ##STR03508## ##STR03509## ##STR03510## ##STR03511## ##STR03512## ##STR03513## ##STR03514## ##STR03515## ##STR03516## ##STR03517## ##STR03518## ##STR03519## ##STR03520## ##STR03521## ##STR03522## ##STR03523## ##STR03524## ##STR03525## ##STR03526## ##STR03527## ##STR03528## ##STR03529## ##STR03530## ##STR03531## ##STR03532## ##STR03533## ##STR03534## ##STR03535## ##STR03536## ##STR03537## ##STR03538## ##STR03539## ##STR03540## ##STR03541## ##STR03542## ##STR03543## ##STR03544## ##STR03545## ##STR03546## ##STR03547## ##STR03548## ##STR03549## ##STR03550## ##STR03551## ##STR03552## ##STR03553## ##STR03554## ##STR03555## ##STR03556## ##STR03557## ##STR03558## ##STR03559## ##STR03560## ##STR03561## ##STR03562## ##STR03563## ##STR03564## ##STR03565## ##STR03566## ##STR03567## ##STR03568## ##STR03569## ##STR03570## ##STR03571## ##STR03572## ##STR03573## ##STR03574## ##STR03575## ##STR03576## ##STR03577## ##STR03578## ##STR03579## ##STR03580## ##STR03581## ##STR03582## ##STR03583## ##STR03584## ##STR03585## ##STR03586## ##STR03587## ##STR03588## ##STR03589## ##STR03590## ##STR03591## ##STR03592## ##STR03593## ##STR03594## ##STR03595## ##STR03596## ##STR03597## ##STR03598## ##STR03599## ##STR03600## ##STR03601## ##STR03602## ##STR03603## ##STR03604## ##STR03605## ##STR03606## ##STR03607## ##STR03608## ##STR03609## ##STR03610## ##STR03611## ##STR03612## ##STR03613## ##STR03614## ##STR03615## ##STR03616## ##STR03617## ##STR03618## ##STR03619## ##STR03620## ##STR03621## ##STR03622## ##STR03623## ##STR03624## ##STR03625## ##STR03626## ##STR03627## ##STR03628## ##STR03629## ##STR03630## ##STR03631## ##STR03632## ##STR03633## ##STR03634## ##STR03635## ##STR03636## ##STR03637## ##STR03638## ##STR03639## ##STR03640## ##STR03641## ##STR03642## ##STR03643## ##STR03644## ##STR03645## ##STR03646## ##STR03647## ##STR03648## ##STR03649## ##STR03650## ##STR03651## ##STR03652## ##STR03653## ##STR03654## ##STR03655## ##STR03656## ##STR03657## ##STR03658## ##STR03659## ##STR03660## ##STR03661## ##STR03662## ##STR03663## ##STR03664## ##STR03665## ##STR03666## ##STR03667## ##STR03668## ##STR03669## ##STR03670## ##STR03671## ##STR03672## ##STR03673## ##STR03674## ##STR03675## ##STR03676## ##STR03677## ##STR03678## ##STR03679## ##STR03680## ##STR03681## ##STR03682## ##STR03683## ##STR03684## ##STR03685## ##STR03686## ##STR03687## ##STR03688## ##STR03689## ##STR03690## ##STR03691## ##STR03692## ##STR03693## ##STR03694## ##STR03695## ##STR03696## ##STR03697## ##STR03698## ##STR03699## ##STR03700## ##STR03701## ##STR03702## ##STR03703## ##STR03704## ##STR03705## ##STR03706## ##STR03707## ##STR03708## ##STR03709## ##STR03710## ##STR03711## ##STR03712## ##STR03713## ##STR03714## ##STR03715## ##STR03716## ##STR03717## ##STR03718## ##STR03719## ##STR03720## ##STR03721## ##STR03722## ##STR03723## ##STR03724## ##STR03725## ##STR03726## ##STR03727## ##STR03728## ##STR03729## ##STR03730## ##STR03731## ##STR03732## ##STR03733## ##STR03734## ##STR03735## ##STR03736## ##STR03737## ##STR03738## ##STR03739## ##STR03740## ##STR03741## ##STR03742## ##STR03743## ##STR03744## ##STR03745## ##STR03746## ##STR03747## ##STR03748## ##STR03749## ##STR03750## ##STR03751## ##STR03752## ##STR03753## ##STR03754## ##STR03755##

11. An organic light-emitting device comprising: a first electrode; a second electrode; and an organic layer arranged between the first electrode and the second electrode and comprising an emission layer, wherein the organic layer comprises the heterocyclic compound of claim 1.

12. The light-emitting device of claim 11, wherein the emission layer comprises the heterocyclic compound.

13. The light-emitting device of claim 12, wherein the emission layer comprises a host and an emitter, the host and the emitter are different from each other, an amount of the host is greater than an amount of the emitter, and the emitter comprises the heterocyclic compound.

14. The organic light-emitting device of claim 13, wherein the emission layer emits blue light.

15. The organic light-emitting device of claim 13, wherein the emitter is a fluorescent emitter, a delayed fluorescence emitter, or a combination thereof.

16. The organic light-emitting device of claim 12, wherein the emission layer comprises a host, an emitter, and a sensitizer, the host, the emitter, and the sensitizer are different from one another, an amount of the host is greater than an amount of the sensitizer, an amount of the sensitizer is greater than an amount of the emitter, and the emitter comprises the heterocyclic compound.

17. The organic light-emitting device of claim 16, wherein the emission layer emits blue light.

18. The organic light-emitting device of claim 16, wherein the emitter is a fluorescent emitter, a delayed fluorescence emitter, or a combination thereof.

19. The organic light-emitting device of claim 16, wherein the heterocyclic compound additionally satisfies Condition 5:
0 μs<T.sub.decay(HC)<5 μs  Condition 5 wherein, in Condition 5, T.sub.decay(HC) indicates a decay time of the heterocyclic compound.

20. An electronic apparatus comprising the organic light-emitting device of claim 11.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0033] FIG. 1 is a schematic cross-sectional view of an organic light-emitting device 10 according to an exemplary embodiment;

[0034] FIG. 2 is a schematic cross-sectional view of an organic light-emitting device 100 according to another exemplary embodiment;

[0035] FIG. 3 is a schematic cross-sectional view of an organic light-emitting device 200 according to an exemplary embodiment; and

[0036] FIGS. 4A to 4E each show a diagram schematically illustrating energy transfer in an emission layer of an organic light-emitting device according to an exemplary embodiment.

DETAILED DESCRIPTION

[0037] Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

[0038] It will be understood that when an element is referred to as being “on” another element, it can be directly on the other element or intervening elements may be present therebetween In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present

[0039] It will be understood that, although the terms “first,” “second,” “third” etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, “a first element,” “component,” “region,” “layer” or “section” discussed below could be termed a second element, component, region, layer or section without departing from the teachings herein.

[0040] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, “a,” “an,” “the,” and “at least one” do not denote a limitation of quantity, and are intended to cover both the singular and plural, unless the context clearly indicates otherwise. For example, “an element” has the same meaning as “at least one element,” unless the context clearly indicates otherwise.

[0041] “Or” means “and/or.” As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof.

[0042] Furthermore, relative terms, such as “lower” or “bottom” and “upper” or “top,” may be used herein to describe one element's relationship to another element as illustrated in the Figures. It will be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. For example, if the device in one of the figures is turned over, elements described as being on the “lower” side of other elements would then be oriented on “upper” sides of the other elements. The exemplary term “lower,” can therefore, encompasses both an orientation of “lower” and “upper,” depending on the particular orientation of the figure. Similarly, if the device in one of the figures is turned over, elements described as “below” or “beneath” other elements would then be oriented “above” the other elements. The exemplary terms “below” or “beneath” can, therefore, encompass both an orientation of above and below.

[0043] “About” or “approximately” as used herein is inclusive of the stated value and means within an acceptable range of deviation for the particular value as determined by one of ordinary skill in the art, considering the measurement in question and the error associated with measurement of the particular quantity (i.e., the limitations of the measurement system). For example, “about” can mean within one or more standard deviations, or within ±30%, 20%, 10% or 5% of the stated value.

[0044] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0045] Exemplary embodiments are described herein with reference to cross section illustrations that are schematic illustrations of idealized embodiments. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments described herein should not be construed as limited to the particular shapes of regions as illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, a region illustrated or described as flat may, typically, have rough and/or nonlinear features. Moreover, sharp angles that are illustrated may be rounded Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region and are not intended to limit the scope of the present claims.

[0046] An aspect of the present disclosure provides a heterocyclic compound represented by Formula 1:

##STR00005##

[0047] In Formula 1, X.sub.11 and X.sub.12 may each independently be a carbon atom, and may be linked to each other via a single bond or a double bond.

[0048] In Formula 1, Y.sub.11 to Y.sub.16 may each independently be a carbon atom, and any neighboring two of Y.sub.11 to Y.sub.16 may be linked via a single bond or a double bond.

[0049] In Formula 1, B.sub.11 may be a group represented by Formula 1A:

##STR00006##

[0050] In Formula 1A, Z.sub.11 to Z.sub.16 may each independently be a carbon atom, and any neighboring two of Z.sub.11 to Z.sub.16 may be linked via a single bond or a double bond.

[0051] In Formula 1A, W.sub.11 and W.sub.12 may each independently be a carbon atom, may be linked via a single bond or a double bond, and may be *1 and *2 in Formula 1.

[0052] For example, in Formulae 1 and 1A, W.sub.11 may be *1 and W.sub.12 may be *2; or may be *2, and W.sub.12 may be *1.

[0053] In Formulae 1 and 1A, A.sub.11 and C.sub.11 to C.sub.14 may each independently be a substituted or unsubstituted C.sub.5-C.sub.30 carbocyclic group or a substituted or unsubstituted C.sub.1-C.sub.30 heterocyclic group.

[0054] In an embodiment, in Formulae 1 and 1A, A.sub.11 and C.sub.11 to C.sub.14 may each independently be a benzene group, a naphthalene group, a phenanthrene group, a furan group, a thiophene group, a pyrrole group, a cyclopentene group, a silole group, a germole group, a benzofuran group, a benzothiophene group, an indole group, an indene group, a benzosilole group, a benzogermole group, a dibenzofuran group, a dibenzothiophene group, a carbazole group, a fluorene group, a dibenzosilole group, a dibenzogermole group, a pyridine group, a pyrimidine group, or a pyridazine group.

[0055] In one or more embodiments, in Formulae 1 and 1A, A.sub.11 and C.sub.11 to C.sub.14 may each independently be a benzene group, a naphthalene group, a benzofuran group, a benzothiophene group, an indole group, an indene group, a benzosilole group, a benzogermole group, a pyridine group, or a pyridazine group.

[0056] In one or more embodiments, in Formulae 1 and 1A, A.sub.11 and C.sub.11 to C.sub.14 may each independently be a benzene group, a naphthalene group, a pyridine group, or a pyridazine group.

[0057] For example, A.sub.11 in Formulae 1 and 1A may be a group represented by Formula 3-1:

##STR00007## [0058] wherein, in Formula 3-1, [0059] X.sub.11 to X.sub.16 may each independently be a nitrogen atom or a carbon atom, and any neighboring two of X.sub.13 to X.sub.16 may each be *1 and *2 in Formula 1, [0060] R.sub.15 may be defined the same as R.sub.11 in Formula 1, and [0061] b15 may be 0, 1, or 2.

[0062] For example, in Formulae 1 and 1A, A.sub.11 may be a group represented by one of Formulae 3-11 to 3-16:

##STR00008## [0063] wherein, in Formulae 3-11 to 3-16, [0064] X.sub.11 to X.sub.16 may each independently be a nitrogen atom or a carbon atom, [0065] W.sub.11 and W.sub.12 may each independently be a nitrogen atom or a carbon atom, and [0066] R.sub.15a and R.sub.16b may each independently be the same as R.sub.11 in Formula 1.

[0067] In Formula 1, R.sub.x may be a group represented by one of Formulae 2-1 to 2-3:

##STR00009## [0068] wherein, in Formulae 2-1 to 2-3, [0069] X.sub.21 may be a single bond, O, S, N(R.sub.28), or C(R.sub.28)(R.sub.29), [0070] X.sub.22 may be a single bond, O, S, N(R.sub.30), or C(R.sub.30)(R.sub.31), [0071] L.sub.21 to L.sub.23 may each independently be a substituted or unsubstituted C.sub.5-C.sub.30 carbocyclic group or a substituted or unsubstituted C.sub.1-C.sub.30 heterocyclic group, [0072] a21 to a23 may each independently be 0, 1, 2, 3, or 4, [0073] R.sub.21 and R.sub.22 may each independently be a substituted or unsubstituted C.sub.1-C.sub.60 alkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenyl group, a substituted or unsubstituted C.sub.2-C.sub.10 heterocycloalkenyl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.7-C.sub.60 alkylaryl group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryl group, a substituted or unsubstituted C.sub.2-C.sub.60 heteroalkylaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, or a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, [0074] R.sub.23 to R.sub.31 may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, —SF.sub.5, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a substituted or unsubstituted C.sub.1-C.sub.60 alkyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkenyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkynyl group, a substituted or unsubstituted C.sub.1-C.sub.60 alkoxy group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenyl group, a substituted or unsubstituted C.sub.2-C.sub.10 heterocycloalkenyl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.7-C.sub.60 alkylaryl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryloxy group, a substituted or unsubstituted C.sub.6-C.sub.60 arylthio group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryl group, a substituted or unsubstituted C.sub.2-C.sub.60 heteroalkylaryl group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryloxy group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroarylthio group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q.sub.1)(Q.sub.2)(Q.sub.3), —C(Q.sub.1)(Q.sub.2)(Q.sub.3), —B(Q.sub.1)(Q.sub.2), —N(Q.sub.1)(Q.sub.2), —P(Q.sub.1)(Q.sub.2), —C(═O)(Q.sub.1), —S(═O)(Q.sub.1), —S(═O).sub.2(Q.sub.1), —P(═O)(Q.sub.1)(Q.sub.2), or —P(═S)(Q.sub.1)(Q.sub.2), [0075] b23 to b26 may each independently be 0, 1, 2, 3, or 4, [0076] Q.sub.1 to Q.sub.3 may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, a C.sub.1-C.sub.60 alkoxy group, a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.2-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.7-C.sub.60 alkylaryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a C.sub.2-C.sub.60 heteroalkylaryl group, a C.sub.1-C.sub.60 heteroaryloxy group, a C.sub.1-C.sub.60 heteroarylthio group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a C.sub.1-C.sub.60 alkyl group that is substituted with at least one deuterium, —F, a cyano group, a C.sub.1-C.sub.60 alkyl group, a C.sub.6-C.sub.60 aryl group, or a combination thereof, or a C.sub.6-C.sub.60 aryl group that is substituted with deuterium, —F, a cyano group, a C.sub.1-C.sub.60 alkyl group, a C.sub.6-C.sub.60 aryl group, or a combination thereof, and [0077] * indicates a binding site to a neighboring atom.

[0078] In an embodiment, in Formulae 2-1 to 2-3, X.sub.21 may be a single bond, and X.sub.22 may be a single bond.

[0079] In an embodiment, in Formulae 2-1 to 2-3, L.sub.21 and L.sub.22 may each independently be a substituted or unsubstituted C.sub.5-C.sub.30 carbocyclic group.

[0080] In one or more embodiments, in Formulae 2-1 to 2-3, L.sub.21 and L.sub.22 may each independently be a benzene group.

[0081] In an embodiment, in Formulae 2-1 to 2-3, a21 and a22 may each independently be 0 or 1.

[0082] In an embodiment, in Formulae 2-1 to 2-3, R.sub.21 and R.sub.22 may each independently be: a C.sub.1-C.sub.20 alkyl group unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, —CD.sub.3, —CD.sub.2H, —CDH.sub.2, —CF.sub.3, —CF.sub.2H, —CFH.sub.2, a hydroxyl group, a cyano group, a nitro group, a C.sub.1-C.sub.20 alkyl group, a deuterated C.sub.2-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl group, a bicyclo[2.2.1]heptyl group, a bicyclo[2.2.2]octyl group, a (C.sub.1-C.sub.20 alkyl)cyclopentyl group, a (C.sub.1-C.sub.20 alkyl)cyclohexyl group, a (C.sub.1-C.sub.20 alkyl)cycloheptyl group, a (C.sub.1-C.sub.20 alkyl)cyclooctyl group, a (C.sub.1-C.sub.20 alkyl)adamantanyl group, a (C.sub.1-C.sub.20 alkyl)norbornanyl group, a (C.sub.1-C.sub.20 alkyl)norbornenyl group, a (C.sub.1-C.sub.20 alkyl)cyclopentenyl group, a (C.sub.1-C.sub.20 alkyl) cyclohexenyl group, a (C.sub.1-C.sub.20 alkyl)cycloheptenyl group, a (C.sub.1-C.sub.20 alkyl)bicyclo[1.1.1]pentyl group, a (C.sub.1-C.sub.20 alkyl)bicyclo[2.1.1]hexyl group, a (C.sub.1-C.sub.20 alkyl)bicyclo[2.2.1]heptyl group, a (C.sub.1-C.sub.20 alkyl)bicyclo[2.2.2]octyl group, a phenyl group, a (C.sub.1-C.sub.20 alkyl)phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, —Si(Q.sub.11)(Q.sub.12)(Q.sub.13), —Ge(Q.sub.11)(Q.sub.12)(Q.sub.13), —C(Q.sub.11)(Q.sub.12)(Q.sub.13), —B(Q.sub.11)(Q.sub.12), —N(Q.sub.11)(Q.sub.12), —P(Q.sub.11)(Q.sub.12), —C(═O)(Q.sub.11), —S(═O)(Q.sub.11), —S(═O).sub.2(Q.sub.11), —P(═O)(Q.sub.11)(Q.sub.12), —P(═S)(Q.sub.11)(12), or any combination thereof; or [0083] a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl group, a bicyclo[2.2.1]heptyl group, a bicyclo[2.2.2]octyl group, a phenyl group, a (C.sub.1-C.sub.20 alkyl)phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, an azacarbazolyl group, an azadibenzofuranyl group, or an azadibenzothiophenyl group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, —CD.sub.3, —CD.sub.2H, —CDH.sub.2, —CF.sub.3, —CF.sub.2H, —CFH.sub.2, a hydroxyl group, a cyano group, a nitro group, a C.sub.1-C.sub.20 alkyl group, a deuterated C.sub.2-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl group, a bicyclo[2.2.1]heptyl group, a bicyclo[2.2.2]octyl group, a (C.sub.1-C.sub.20 alkyl)cyclopentyl group, a (C.sub.1-C.sub.20 alkyl)cyclohexyl group, a (C.sub.1-C.sub.20 alkyl)cycloheptyl group, a (C.sub.1-C.sub.20 alkyl)cyclooctyl group, a (C.sub.1-C.sub.20 alkyl)adamantanyl group, a (C.sub.1-C.sub.20 alkyl)norbornanyl group, a (C.sub.1-C.sub.20 alkyl)norbornenyl group, a (C.sub.1-C.sub.20 alkyl)cyclopentenyl group, a (C.sub.1-C.sub.20 alkyl)cyclohexenyl group, a (C.sub.1-C.sub.20 alkyl)cycloheptenyl group, a (C.sub.1-C.sub.20 alkyl)bicyclo[1.1.1]pentyl group, a (C.sub.1-C.sub.20 alkyl)bicyclo[2.1.1]hexyl group, a (C.sub.1-C.sub.20 alkyl)bicyclo[2.2.1]heptyl group, a (C.sub.1-C.sub.20 alkyl)bicyclo[2.2.2]octyl group, a phenyl group, a (C.sub.1-C.sub.20 alkyl)phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, —Si(Q.sub.21)(Q.sub.22)(Q.sub.23), —Ge(Q.sub.21)(Q.sub.22)(Q.sub.23), —C(Q.sub.21)(Q.sub.22)(Q.sub.23), —B(Q.sub.21)(Q.sub.22), —N(Q.sub.21)(Q.sub.22), —P(Q.sub.21)(Q.sub.22), —C(═O)(Q.sub.21), —S(═O)(Q.sub.21), —S(═O).sub.2(Q.sub.21), —P(═O)(Q.sub.21)(Q.sub.22), —P(═S)(Q.sub.21)(Q.sub.22), or any combination thereof, and [0084] Q.sub.11 to Q.sub.13 and Q.sub.21 to Q.sub.23 may each independently be: deuterium, —F, —CH.sub.3, —CD.sub.3, —CD.sub.2H, —CDH.sub.2, —CH.sub.2CH.sub.3, —CH.sub.2CD.sub.3, —CH.sub.2CD.sub.2H, —CH.sub.2CDH.sub.2, —CHDCH.sub.3, —CHDCD.sub.2H, —CHDCDH.sub.2, —CHDCD.sub.3, —CD.sub.2CD.sub.3, —CD.sub.2CD.sub.2H, —CD.sub.2CDH.sub.2, —CF.sub.3, —CF.sub.2H, —CFH.sub.2, —CH.sub.2CF.sub.3, —CH.sub.2CF.sub.2H, —CH.sub.2CFH.sub.2, —CHFCH.sub.3, —CHFCF.sub.2H, —CHFCFH.sub.2, —CHFCF.sub.3, —CF.sub.2CF.sub.3, —CF.sub.2CF.sub.2H, or —CF.sub.2CFH.sub.2; or [0085] an n-propyl group, an iso-propyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, a neopentyl group, an isopentyl group, a sec-pentyl group, a 3-pentyl group, a sec-isopentyl group, a phenyl group, a biphenyl group, or a naphthyl group, each unsubstituted or substituted with deuterium, —F, a C.sub.1-C.sub.10 alkyl group, a deuterated C.sub.1-C.sub.10 alkyl group, a phenyl group, or any combination thereof.

[0086] In one or more embodiments, in Formulae 2-1 to 2-3, R.sub.21 and R.sub.22 may each independently be: a phenyl group, a (C.sub.1-C.sub.20 alkyl)phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, or a dibenzocarbazolyl group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, —CD.sub.3, —CD.sub.2H, —CDH.sub.2, —CF.sub.3, —CF.sub.2H, —CFH.sub.2, a hydroxyl group, a cyano group, a nitro group, a C.sub.1-C.sub.20 alkyl group, a deuterated C.sub.2-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl group, a bicyclo[2.2.1]heptyl group, a bicyclo[2.2.2]octyl group, a (C.sub.1-C.sub.20 alkyl)cyclopentyl group, a (C.sub.1-C.sub.20 alkyl)cyclohexyl group, a (C.sub.1-C.sub.20 alkyl)cycloheptyl group, a (C.sub.1-C.sub.20 alkyl)cyclooctyl group, a (C.sub.1-C.sub.20 alkyl)adamantanyl group, a (C.sub.1-C.sub.20 alkyl)norbornanyl group, a (C.sub.1-C.sub.20 alkyl)norbornenyl group, a (C.sub.1-C.sub.20 alkyl)cyclopentenyl group, a (C.sub.1-C.sub.20 alkyl)cyclohexenyl group, a (C.sub.1-C.sub.20 alkyl)cycloheptenyl group, a (C.sub.1-C.sub.20 alkyl)bicyclo[1.1.1]pentyl group, a (C.sub.1-C.sub.20 alkyl)bicyclo[2.1.1]hexyl group, a (C.sub.1-C.sub.20 alkyl)bicyclo[2.2.1]heptyl group, a (C.sub.1-C.sub.20 alkyl)bicyclo[2.2.2]octyl group, a phenyl group, a (C.sub.1-C.sub.20 alkyl)phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, or any combination thereof.

[0087] In one or more embodiments, in Formulae 2-1 to 2-3, R.sub.21 and R.sub.22 may each independently be —CH.sub.3, —CD.sub.3, —CD.sub.2H, —CDH.sub.2, —CF.sub.3, —CF.sub.2H, —CFH.sub.2, a group represented by one of Formulae 10-12 to 10-23, 10-38 to 10-130, and 10-238 to 10-272, a group represented by one of Formulae 10-12 to 10-23, 10-38 to 10-130, and 10-238 to 10-272 in which at least one hydrogen is substituted with deuterium, a group represented by one of Formulae 10-12 to 10-23, 10-38 to 10-130, and 10-238 to 10-272 in which at least one hydrogen is substituted with —F:

##STR00010## ##STR00011## ##STR00012## ##STR00013## ##STR00014## ##STR00015## ##STR00016## ##STR00017## ##STR00018## ##STR00019## ##STR00020## ##STR00021## ##STR00022## ##STR00023## ##STR00024## ##STR00025## ##STR00026## ##STR00027## ##STR00028## ##STR00029## ##STR00030##

[0088] In Formulae 10-12 to 10-23, 10-38 to 10-130, and 10-238 to 10-272, [0089] “Ph” represents a phenyl group, and [0090] * indicates a binding site to a neighboring atom.

[0091] In an embodiment, in Formulae 2-1 to 2-3, R.sub.23 to R.sub.31 may each independently be: hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, —SF.sub.5, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkenyl group, a C.sub.1-C.sub.20 alkoxy group, or a C.sub.1-C.sub.20 alkylthio group; [0092] a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkenyl group, a C.sub.1-C.sub.20 alkoxy group, or a C.sub.1-C.sub.20 alkylthio group, each substituted with deuterium, —F, —Cl, —Br, —I, —CD.sub.3, —CD.sub.2H, —CDH.sub.2, —CF.sub.3, —CF.sub.2H, —CFH.sub.2, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.10 alkyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl group, a bicyclo[2.2.1]heptyl group, a bicyclo[2.2.2]octyl group, a (C.sub.1-C.sub.20 alkyl)cyclopentyl group, a (C.sub.1-C.sub.20 alkyl)cyclohexyl group, a (C.sub.1-C.sub.20 alkyl)cycloheptyl group, a (C.sub.1-C.sub.20 alkyl)cyclooctyl group, a (C.sub.1-C.sub.20 alkyl)adamantanyl group, a (C.sub.1-C.sub.20 alkyl)norbornanyl group, a (C.sub.1-C.sub.20 alkyl)norbornenyl group, a (C.sub.1-C.sub.20 alkyl)cyclopentenyl group, a (C.sub.1-C.sub.20 alkyl)cyclohexenyl group, a (C.sub.1-C.sub.20 alkyl)cycloheptenyl group, a (C.sub.1-C.sub.20 alkyl)bicyclo[1.1.1]pentyl group, a (C.sub.1-C.sub.20 alkyl)bicyclo[2.1.1]hexyl group, a (C.sub.1-C.sub.20 alkyl)bicyclo[2.2.1]heptyl group, a (C.sub.1-C.sub.20 alkyl)bicyclo[2.2.2]octyl group, a phenyl group, a (C.sub.1-C.sub.20 alkyl)phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a pyridinyl group, a pyrimidinyl group, or any combination thereof; [0093] a cyclopentyl group, a cyclohexyl group, a cycoheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl group, a bicyclo[2.2.1]heptyl group, a bicyclo[2.2.2]octyl group, a phenyl group, a (C.sub.1-C.sub.20 alkyl)phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, a benzoisothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, an azacarbazolyl group, an azadibenzofuranyl group, or an azadibenzothiophenyl group, each unsubstituted or substituted with deuterium, —F, —CI, —Br, —I, —CD.sub.3, —CD.sub.2H, —CDH.sub.2, —CF.sub.3, —CF.sub.2H, —CFH.sub.2, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a deuterated C.sub.2-C.sub.20 alkyl group, a fluorinated C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl group, a bicyclo[2.2.1]heptyl group, a bicyclo[2.2.2]octyl group, a (C.sub.1-C.sub.20 alkyl)cyclopentyl group, a (C.sub.1-C.sub.20 alkyl)cyclohexyl group, a (C.sub.1-C.sub.20 alkyl)cycloheptyl group, a (C.sub.1-C.sub.20 alkyl)cyclooctyl group, a (C.sub.1-C.sub.20 alkyl)adamantanyl group, a (C.sub.1-C.sub.20 alkyl)norbornanyl group, a (C.sub.1-C.sub.20 alkyl)norbornenyl group, a (C.sub.1-C.sub.20 alkyl)cyclopentenyl group, a (C.sub.1-C.sub.20 alkyl)cyclohexenyl group, a (C.sub.1-C.sub.20 alkyl)cycloheptenyl group, a (C.sub.1-C.sub.20 alkyl)bicyclo[1.1.1]pentyl group, a (C.sub.1-C.sub.20 alkyl)bicyclo[2.1.1]hexyl group, a (C.sub.1-C.sub.20 alkyl)bicyclo[2.2.1]heptyl group, a (C.sub.1-C.sub.20 alkyl)bicyclo[2.2.2]octyl group, a phenyl group, a (C.sub.1-C.sub.20 alkyl)phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzoimidazolyl group, a benzofuranyl group, a benzothiophenyl group, a benzoisothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, an azacarbazolyl group, an azadibenzofuranyl group, an azadibenzothiophenyl group, or any combination thereof; or [0094] —Si(Q.sub.1)(Q.sub.2)(Q.sub.3), —C(Q.sub.1)(Q.sub.2)(Q.sub.3), —B(Q.sub.1)(Q.sub.2), or —N(Q.sub.1)(Q.sub.2), and Q.sub.1 to Q.sub.3 may each independently be: [0095] deuterium, —F, —CH.sub.3, —CD.sub.3, —CD.sub.2H, —CDH.sub.2, —CH.sub.2CH.sub.3, —CH.sub.2CD.sub.3, —CH.sub.2CD.sub.2H, —CH.sub.2CDH.sub.2, —CHDCH.sub.3, —CHDCD.sub.2H, —CHDCDH.sub.2, —CHDCD.sub.3, —CD.sub.2CD.sub.3, —CD.sub.2CD.sub.2H, —CD.sub.2CDH.sub.2, —CF.sub.3, —CF.sub.2H, —CFH.sub.2, —CH.sub.2CF.sub.3, —CH.sub.2CF.sub.2H, —CH.sub.2CFH.sub.2, —CHFCH.sub.3, —CHFCF.sub.2H, —CHFCFH.sub.2, —CHFCF.sub.3, —CF.sub.2CF.sub.3, —CF.sub.2CF.sub.2H, or —CF.sub.2CFH.sub.2; or [0096] an n-propyl group, an iso-propyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, a neopentyl group, an isopentyl group, a sec-pentyl group, a 3-pentyl group, a sec-isopentyl group, a phenyl group, a biphenyl group, or a naphthyl group, each unsubstituted or substituted with deuterium, —F, a C.sub.1-C.sub.10 alkyl group, a phenyl group, or any combination thereof.

[0097] In one or more embodiments, in Formulae 2-1 to 2-3, R.sub.23 to R.sub.31 may each independently be hydrogen, deuterium, —F, —CH.sub.3, —CD.sub.3, —CD.sub.2H, —CDH.sub.2, —CF.sub.3, —CF.sub.2H, —CFH.sub.2, a C.sub.2-C.sub.10 alkenyl group, a C.sub.1-C.sub.10 alkoxy group, a C.sub.1-C.sub.10 alkylthio group, a group represented by one of Formulae 9-1 to 9-39, a group represented by one of Formulae 9-1 to 9-39 in which at least one hydrogen is substituted with deuterium, a group represented by one of Formulae 9-1 to 9-39 in which at least one hydrogen is substituted with —F, a group represented by one of Formulae 9-201 to 9-227, a group represented by one of Formulae 9-201 to 9-227 in which at least one hydrogen is substituted with deuterium, a group represented by one of Formulae 9-201 to 9-227 in which at least one hydrogen is substituted with —F, a group represented by one of Formulae 10-1 to 10-129, a group represented by one of Formulae 10-1 to 10-129 in which at least one hydrogen is substituted with deuterium, a group represented by one of Formulae 10-1 to 10-129 in which at least one hydrogen is substituted with —F, a group represented by one of Formulae 10-201 to 10-350, a group represented by one of Formulae 10-201 to 10-350 in which at least one hydrogen is substituted with deuterium, a group represented by one of Formulae 10-201 to 10-350 in which at least one hydrogen is substituted with —F, —Si(Q.sub.3)(Q.sub.4)(Q.sub.5), or —C(Q.sub.1)(Q.sub.2)(Q.sub.3), and [0098] Q.sub.1 to Q.sub.3 may each independently be: [0099] deuterium, —F, —CH.sub.3, —CD.sub.3, —CD.sub.2H, —CDH.sub.2, —CH.sub.2CH.sub.3, —CH.sub.2CD.sub.3, —CH.sub.2CD.sub.2H, —CH.sub.2CDH.sub.2, —CHDCH.sub.3, —CHDCD.sub.2H, —CHDCDH.sub.2, —CHDCD.sub.3, —CD.sub.2CD.sub.3, —CD.sub.2CD.sub.2H, —CD.sub.2CDH.sub.2, —CF.sub.3, —CF.sub.2H, —CFH.sub.2, —CH.sub.2CF.sub.3, —CH.sub.2CF.sub.2H, —CH.sub.2CFH.sub.2, —CHFCH.sub.3, —CHFCF.sub.2H, —CHFCFH.sub.2, —CHFCF.sub.3, —CF.sub.2CF.sub.3, —CF.sub.2CF.sub.2H, or —CF.sub.2CFH.sub.2; or [0100] an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, a neopentyl group, an isopentyl group, a sec-pentyl group, a 3-pentyl group, a sec-isopentyl group, a phenyl group, a biphenyl group, or a naphthyl group, each unsubstituted or substituted with deuterium, —F, a C.sub.1-C.sub.10 alkyl group, a phenyl group, or any combination thereof:

##STR00031## ##STR00032## ##STR00033## ##STR00034## ##STR00035## ##STR00036## ##STR00037## ##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##

[0101] In Formulae 9-1 to 9-39, 9-201 to 9-236, 10-1 to 10-130, and 10-201 to 10-358, * indicates a binding site to an adjacent atom, “Ph” represents a phenyl group, “TMS” and “SiMe.sub.3” each represent a trimethylsilyl group, and “TMG” and “GeMe.sub.3” each represent a trimethylgermyl group.

[0102] The “group represented by Formulae 9-1 to 9-39 in which at least one hydrogen is substituted with deuterium” and the “group represented by Formulae 9-201 to 9-236 in which at least one hydrogen is substituted with deuterium” may each be, for example, a group represented by one of Formulae 9-501 to 9-514 and 9-601 to 9-636:

##STR00065## ##STR00066## ##STR00067## ##STR00068## ##STR00069##

[0103] The “group represented by Formulae 9-1 to 9-39 in which at least one hydrogen is substituted with —F” and the “group represented by Formulae 9-201 to 9-236 in which at least one hydrogen is substituted with —F” may each be, for example, a group represented by one of Formulae 9-701 to 9-710:

##STR00070##

[0104] The “group represented by Formulae 10-1 to 10-130 in which at least one hydrogen is substituted with a deuterium” and the “group represented by Formulae 10-201 to 10-358 in which at least one hydrogen is substituted with deuterium” may each be, for example, a group represented by one of Formulae 10-501 to 576:

##STR00071## ##STR00072## ##STR00073## ##STR00074## ##STR00075## ##STR00076## ##STR00077## ##STR00078## ##STR00079## ##STR00080## ##STR00081## ##STR00082##

[0105] The “group represented by Formulae 10-1 to 10-130 in which at least one hydrogen is substituted with —F” and the “group represented by Formulae 10-201 to 10-358 in which at least one hydrogen is substituted with —F” may each be, for example, a group represented by one of Formulae 10-601 to 617:

##STR00083## ##STR00084##

[0106] In Formulae 1 and 1A, R.sub.y and R.sub.11 to R.sub.15 may each independently be a group represented by one of Formulae 2-1 to 2-3, hydrogen, deuterium, —F, —Cl, —Br, —I, —SFS, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a substituted or unsubstituted C.sub.1-C.sub.60 alkyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkenyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkynyl group, a substituted or unsubstituted C.sub.1-C.sub.60 alkoxy group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenyl group, a substituted or unsubstituted C.sub.2-C.sub.10 heterocycloalkenyl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.7-C.sub.60 alkylaryl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryloxy group, a substituted or unsubstituted C.sub.6-C.sub.60 arylthio group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryl group, a substituted or unsubstituted C.sub.2-C.sub.60 heteroalkylaryl group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryloxy group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroarylthio group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q.sub.1)(Q.sub.2)(Q.sub.3), —C(Q.sub.1)(Q.sub.2)(Q.sub.3), —B(Q.sub.1)(Q.sub.2), —N(Q.sub.1)(Q.sub.2), —P(Q.sub.1)(Q.sub.2), —C(═O)(Q.sub.1), —S(═O)(Q.sub.1), —S(═O).sub.2(Q.sub.1), —P(═O)(Q.sub.1)(Q.sub.2), or —P(═S)(Q.sub.1)(Q.sub.2), and [0107] Q.sub.1 to Q.sub.3 may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, a C.sub.1-C.sub.60 alkoxy group, a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.2-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.7-C.sub.60 alkylaryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a C.sub.2-C.sub.60 heteroalkylaryl group, a C.sub.1-C.sub.60 heteroaryloxy group, a C.sub.1-C.sub.60 heteroarylthio group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a C.sub.1-C.sub.60 alkyl group substituted with at least one of deuterium, —F, a cyano group, a C.sub.1-C.sub.60 alkyl group, a C.sub.6-C.sub.60 aryl group, or a combination thereof, or a C.sub.6-C.sub.60 aryl group substituted with at least one of deuterium, —F, a cyano group, a C.sub.1-C.sub.60 alkyl group, a C.sub.6-C.sub.60 aryl group, or a combination thereof.

[0108] In an embodiment, in Formulae 1 and 1A, R.sub.y and R.sub.11 to R.sub.15 may each independently be groups represented by Formulae 2-1 to 2-3 and/or R.sub.23 may be defined the same as described above.

[0109] In an embodiment, R.sub.x and R.sub.y may each independently be a group represented by one of Formulae 2-1 to 2-3.

[0110] In Formulae 1 and 1A, b11 to b14 may each independently be 0, 1, 2, 3, or 4. In Formulae 1 and 1A, b11 to b14 indicate the number of occurrences of R.sub.11 to R.sub.14, respectively.

[0111] In Formulae 1 and 1A, b15 may be 0, 1, or 2. In Formulae 1 and 1A, b15 indicates the number of occurrences of R.sub.15.

[0112] In an embodiment, the heterocyclic compound may be represented by one of Formulae 11 and 12:

##STR00085## [0113] wherein, in Formulae 11 and 12, [0114] X.sub.11, X.sub.12, Y.sub.11 to Y.sub.16, Z.sub.11 to Z.sub.16, W.sub.11, W.sub.12, A.sub.11, C.sub.11 to C.sub.14, R.sub.x, R.sub.y, R.sub.11 to R.sub.14, and b.sub.11 to b.sub.14 may each be the same as described in Formulae 1 and 1A.

[0115] For example, in Formulae 11 and 12, A.sub.11 may be groups represented by Formulae 3-11 to 3-16.

[0116] In one or more embodiments, the heterocyclic compound may be represented by Formulae 11-1 or 12-1:

##STR00086## [0117] wherein, in Formulae 11-1 and 12-1, [0118] X.sub.11, X.sub.12, W.sub.11, W.sub.12, A.sub.11, R.sub.x, and R.sub.y may each be the same as described in Formulae 1 and 1A, [0119] R.sub.11a to R.sub.11c, R.sub.12a to R.sub.12c, R.sub.13a to R.sub.13c, and R.sub.14a to R.sub.14c may each be the same as described in connection with R.sub.11 in Formula 1, and any neighboring two of R.sub.11a to R.sub.11c, R.sub.12a to R.sub.12c, R.sub.13a to R.sub.13c, and R.sub.14a to R.sub.14c may optionally be combined with each other to form a ring.

[0120] In one or more embodiments, the heterocyclic compound may be a compound of Group C:

##STR00087## ##STR00088## ##STR00089## ##STR00090## ##STR00091## ##STR00092## ##STR00093## ##STR00094## ##STR00095## ##STR00096## ##STR00097## ##STR00098## ##STR00099## ##STR00100## ##STR00101## ##STR00102## ##STR00103## ##STR00104## ##STR00105## ##STR00106## ##STR00107## ##STR00108## ##STR00109## ##STR00110## ##STR00111## ##STR00112## ##STR00113## ##STR00114## ##STR00115## ##STR00116## ##STR00117## ##STR00118## ##STR00119## ##STR00120## ##STR00121## ##STR00122## ##STR00123## ##STR00124## ##STR00125## ##STR00126## ##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## ##STR00164## ##STR00165## ##STR00166## ##STR00167## ##STR00168## ##STR00169## ##STR00170## ##STR00171## ##STR00172## ##STR00173## ##STR00174## ##STR00175## ##STR00176##

##STR00177## ##STR00178## ##STR00179## ##STR00180## ##STR00181## ##STR00182## ##STR00183## ##STR00184## ##STR00185## ##STR00186## ##STR00187## ##STR00188## ##STR00189## ##STR00190## ##STR00191## ##STR00192## ##STR00193## ##STR00194## ##STR00195## ##STR00196## ##STR00197## ##STR00198## ##STR00199## ##STR00200## ##STR00201## ##STR00202## ##STR00203## ##STR00204## ##STR00205## ##STR00206## ##STR00207## ##STR00208## ##STR00209## ##STR00210## ##STR00211## ##STR00212## ##STR00213## ##STR00214## ##STR00215## ##STR00216## ##STR00217## ##STR00218## ##STR00219## ##STR00220## ##STR00221## ##STR00222## ##STR00223## ##STR00224## ##STR00225## ##STR00226## ##STR00227## ##STR00228## ##STR00229## ##STR00230## ##STR00231## ##STR00232## ##STR00233## ##STR00234## ##STR00235## ##STR00236## ##STR00237## ##STR00238## ##STR00239## ##STR00240## ##STR00241## ##STR00242## ##STR00243## ##STR00244## ##STR00245## ##STR00246## ##STR00247## ##STR00248## ##STR00249## ##STR00250## ##STR00251## ##STR00252## ##STR00253## ##STR00254## ##STR00255## ##STR00256## ##STR00257## ##STR00258## ##STR00259## ##STR00260## ##STR00261## ##STR00262## ##STR00263## ##STR00264## ##STR00265## ##STR00266## ##STR00267## ##STR00268## ##STR00269## ##STR00270## ##STR00271## ##STR00272##

##STR00273## ##STR00274## ##STR00275## ##STR00276## ##STR00277## ##STR00278## ##STR00279## ##STR00280## ##STR00281## ##STR00282## ##STR00283## ##STR00284## ##STR00285## ##STR00286## ##STR00287## ##STR00288## ##STR00289## ##STR00290## ##STR00291## ##STR00292## ##STR00293## ##STR00294## ##STR00295## ##STR00296## ##STR00297##

##STR00298## ##STR00299## ##STR00300## ##STR00301## ##STR00302## ##STR00303## ##STR00304## ##STR00305## ##STR00306## ##STR00307## ##STR00308## ##STR00309## ##STR00310## ##STR00311## ##STR00312## ##STR00313## ##STR00314## ##STR00315## ##STR00316## ##STR00317## ##STR00318## ##STR00319## ##STR00320## ##STR00321## ##STR00322## ##STR00323## ##STR00324## ##STR00325## ##STR00326## ##STR00327## ##STR00328## ##STR00329## ##STR00330## ##STR00331## ##STR00332## ##STR00333## ##STR00334## ##STR00335## ##STR00336## ##STR00337## ##STR00338## ##STR00339## ##STR00340##

##STR00341## ##STR00342## ##STR00343## ##STR00344## ##STR00345## ##STR00346## ##STR00347## ##STR00348## ##STR00349## ##STR00350## ##STR00351## ##STR00352## ##STR00353## ##STR00354## ##STR00355## ##STR00356## ##STR00357## ##STR00358## ##STR00359## ##STR00360## ##STR00361## ##STR00362## ##STR00363## ##STR00364## ##STR00365## ##STR00366## ##STR00367## ##STR00368## ##STR00369## ##STR00370## ##STR00371## ##STR00372## ##STR00373## ##STR00374## ##STR00375## ##STR00376## ##STR00377## ##STR00378## ##STR00379## ##STR00380## ##STR00381## ##STR00382## ##STR00383## ##STR00384## ##STR00385##

##STR00386## ##STR00387## ##STR00388## ##STR00389## ##STR00390## ##STR00391## ##STR00392## ##STR00393## ##STR00394## ##STR00395## ##STR00396## ##STR00397## ##STR00398## ##STR00399## ##STR00400## ##STR00401## ##STR00402## ##STR00403## ##STR00404## ##STR00405## ##STR00406## ##STR00407## ##STR00408## ##STR00409## ##STR00410## ##STR00411## ##STR00412## ##STR00413## ##STR00414## ##STR00415## ##STR00416## ##STR00417## ##STR00418## ##STR00419## ##STR00420## ##STR00421## ##STR00422## ##STR00423## ##STR00424## ##STR00425## ##STR00426## ##STR00427## ##STR00428## ##STR00429## ##STR00430## ##STR00431## ##STR00432## ##STR00433## ##STR00434## ##STR00435##

##STR00436## ##STR00437## ##STR00438## ##STR00439## ##STR00440## ##STR00441## ##STR00442## ##STR00443## ##STR00444## ##STR00445## ##STR00446## ##STR00447## ##STR00448## ##STR00449## ##STR00450## ##STR00451## ##STR00452## ##STR00453## ##STR00454## ##STR00455## ##STR00456## ##STR00457## ##STR00458## ##STR00459## ##STR00460## ##STR00461## ##STR00462## ##STR00463## ##STR00464## ##STR00465## ##STR00466## ##STR00467## ##STR00468## ##STR00469## ##STR00470## ##STR00471## ##STR00472## ##STR00473## ##STR00474## ##STR00475## ##STR00476## ##STR00477## ##STR00478## ##STR00479## ##STR00480## ##STR00481## ##STR00482## ##STR00483## ##STR00484## ##STR00485## ##STR00486## ##STR00487## ##STR00488## ##STR00489## ##STR00490## ##STR00491## ##STR00492## ##STR00493## ##STR00494## ##STR00495## ##STR00496## ##STR00497## ##STR00498## ##STR00499## ##STR00500## ##STR00501## ##STR00502## ##STR00503## ##STR00504## ##STR00505## ##STR00506## ##STR00507## ##STR00508## ##STR00509##

##STR00510## ##STR00511## ##STR00512## ##STR00513## ##STR00514## ##STR00515## ##STR00516## ##STR00517## ##STR00518## ##STR00519## ##STR00520## ##STR00521## ##STR00522## ##STR00523## ##STR00524## ##STR00525## ##STR00526## ##STR00527## ##STR00528## ##STR00529## ##STR00530## ##STR00531## ##STR00532## ##STR00533## ##STR00534## ##STR00535## ##STR00536## ##STR00537## ##STR00538## ##STR00539## ##STR00540## ##STR00541## ##STR00542## ##STR00543## ##STR00544## ##STR00545## ##STR00546## ##STR00547## ##STR00548## ##STR00549## ##STR00550## ##STR00551## ##STR00552## ##STR00553## ##STR00554## ##STR00555##

##STR00556## ##STR00557## ##STR00558## ##STR00559## ##STR00560## ##STR00561## ##STR00562## ##STR00563## ##STR00564## ##STR00565## ##STR00566## ##STR00567## ##STR00568## ##STR00569## ##STR00570## ##STR00571## ##STR00572## ##STR00573## ##STR00574## ##STR00575## ##STR00576## ##STR00577## ##STR00578## ##STR00579## ##STR00580## ##STR00581## ##STR00582## ##STR00583## ##STR00584## ##STR00585## ##STR00586## ##STR00587##

[0121] Since the heterocyclic compound has a rigid structure in which aromatic hydrocarbon rings or heteroaromatic rings are condensed, structural relaxation in an excited state may be suppressed. As a result, the heterocyclic compound may have a narrow width of blue emission spectrum and improved colorimetric purity.

[0122] The heterocyclic compound may include two partial structures represented by

##STR00588##

(hereinafter referred to as “ICz partial structure”). In this regard, compared to the heterocyclic compound including one ICz partial structure, the heterocyclic compound disclosed herein may have improved multi-resonance characteristics. Accordingly, regardless of ΔE.sub.ST value, the reverse intersystem crossing (RISC) speed may be improved, thereby improving the efficiency of the organic light-emitting device including the heterocyclic compound.

[0123] Furthermore, due to the improved multi-resonance characteristics, the heterocyclic compound may have relatively small full width at half maximum (FWHM), and accordingly, the organic light-emitting device including the heterocyclic compound may have improved color purity and/or improved conversion efficiency. For example, the FWHM of the heterocyclic compound may be less than 35 nm.

[0124] When the heterocyclic compound serves as a dopant in the organic light-emitting device, the heterocyclic compound may emit blue light, for example, blue light having a maximum emission wavelength of less than or equal to about 550 nm. For example, the maximum emission wavelength of the blue light may be in a range of about 400 nm to about 500 nm, for example, about 420 nm to about 480 nm, or for example, may be less than or equal to about 465 nm. The “maximum emission wavelength” as used herein refers to a wavelength of which the emission intensity is greatest. In other words, the “maximum emission wavelength” may be referred to as “peak emission wavelength.”

[0125] When the heterocyclic compound serves as a dopant in the organic light-emitting device, the organic light-emitting device may have CIEy of less than or equal to about 0.09. For example, the CIEy of the organic light-emitting device may be less than or equal to about 0.07.

[0126] A peak wavelength at photoluminescence (PL) and FWHM at PL may each be measured and/or calculated using a spectrofluorophotometer.

[0127] In the heterocyclic compound, R.sub.x is necessarily substituted at a specific position, and thus N of the heterocyclic compound is not exposed to the outside, thereby improving stability of the heterocyclic compound as we all color reproducibility of the heterocyclic compound. In addition, in the heterocyclic compound, R.sub.x is necessarily substituted at a specific position, so that steric hindrance of the heterocyclic compound may be improved, thereby reducing interaction with a host. Accordingly, the organic light-emitting device including the heterocyclic compound may provide improved efficiency and improved color reproducibility.

[0128] In particular, in the heterocyclic compound, R.sub.x is selected as a chromophore substituent having a specific structure including, for example, an amino group or a carbazole, and thus the substitution effect of R.sub.x may maximize the luminescence efficiency.

[0129] The heterocyclic compound may satisfy Conditions 1 to 4:

|ΔE.sub.ST−ΔE′.sub.TT|<0.3 eV  Condition 1:

0 eV<ΔE.sub.ST2+ΔE′.sub.TT≤1.0 eV  Condition 2:

0 eV<ΔE′.sub.TT≤0.30 eV  Condition 3:

ΔE.sub.ST2>0 eV  Condition 4:

[0130] In Conditions 1 to 4, [0131] ΔE.sub.ST indicates a difference between a lowest excited singlet energy level calculated in an Si equilibrium structure of the heterocyclic compound and a lowest excited triplet energy level calculated in a T.sub.1 equilibrium structure of the heterocyclic compound, [0132] ΔE.sub.ST2 indicates a difference between a lowest excited singlet energy level calculated in an Si equilibrium structure of the heterocyclic compound and a second lowest excited triplet energy level calculated in a T.sub.2 equilibrium structure of the heterocyclic compound, and [0133] ΔE′.sub.TT indicates a difference between a second lowest excited triplet energy level calculated in an T.sub.2 equilibrium structure of the heterocyclic compound and a lowest excited triplet energy level calculated in a T.sub.2 equilibrium structure of the heterocyclic compound.

[0134] The equilibrium structure is optimized using a Turbomole program (see [F. Furche et al. WIRESs: Comput. Mol. Sci. 4, 91-100 (2014)]). In detail, a time-dependent density functional theory (DFT) using PBEO functional within the Tamm-Dancoff approximation is used for structural optimization in the T.sub.1, T.sub.2, and S.sub.1 states. Frequency calculations are performed to obtain normal modes, and the lowest energy structure is identified. The nonadiabatic coupling between the excited triplet state and the Ti state is calculated using a Q-Chem program (see [Y. Shao et al. Mol. Phys. 113, 184-215 (2015)]). In addition, the Q-Chem program calculates spin-orbit couplings for TDDFT states using the one-electron Breit-Pauli spin-orbit operator. For all atoms, the def2-SVP basis sets are used.

[0135] In detail, the heterocyclic compound may satisfy Condition 3A:

0 eV<ΔE′.sub.TT≤0.15 eV  Condition 3A:

[0136] In Condition 3A, ΔE′TT is the same as described above.

[0137] In general, compounds having a relatively small ΔE.sub.ST value may emit thermal activated delayed fluorescence (TADF). However, even though the ΔE.sub.ST value of the heterocyclic compound is relatively large, as the heterocyclic compound satisfies Conditions 1 to 4, the heterocyclic compound may emit TADF, and an organic light-emitting device including the heterocyclic compound may have improved efficiency.

[0138] Furthermore, by using the heterocyclic compound as a sensitizer, energy transferred to a triplet state may undergo RISC to a singlet state. Then, the singlet energy of the heterocyclic compound may be transferred to a dopant by Förster energy transfer. Thus, an organic light-emitting device including the heterocyclic compound may also have improved efficiency and improved lifespan at the same time.

[0139] The synthesis method of the heterocyclic compound according to one or more embodiments is not particularly limited and may be synthesized according to a known synthesis method. In particular, it may be synthesized according to or in view of the method described in the Examples. For example, in the method described in the Examples, the heterocyclic compound according to one or more embodiments may be synthesized through modifications such as changing raw materials and reaction conditions, adding or excluding some processes, or appropriately combining with other known synthesis methods.

[0140] The method of identifying a structure of the heterocyclic compound according to one or more embodiments is not particularly limited. The heterocyclic compound containing nitrogen according to one or more embodiments may be identified by a known method, for example, NMR or LC-MS.

[0141] Description of FIG. 1

[0142] FIG. 1 is a schematic view of an organic light-emitting device 10 according to an exemplary embodiment. Hereinafter a structure and a method of manufacturing the organic light-emitting device 10, according to an embodiment, will be described with reference to FIG. 1.

[0143] In FIG. 1, an organic light-emitting device 10 includes a first electrode 11, a second electrode 19 facing the first electrode 11, and an organic layer 10A between the first electrode 11 and the second electrode 19.

[0144] In FIG. 1, the organic layer 10A includes an emission layer 15, a hole transport region 12 is between the first electrode 11 and an emission layer 15, and an electron transport region 17 is between the emission layer 15 and the second electrode 19.

[0145] A substrate may be additionally disposed under the first electrode 11 or on the second electrode 19. The substrate may be a conventional substrate used in organic light-emitting devices, e.g., a glass substrate or a transparent plastic substrate, each having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and water repellency.

[0146] First Electrode 11

[0147] The first electrode 11 may be produced by depositing or sputtering, onto the substrate, a material for forming the first electrode 11. The first electrode 11 may be an anode. The material for forming the first electrode 11 may be a material with a high work function for easy hole injection.

[0148] The first electrode 11 may be a reflective electrode, a semi-transmissive electrode, or a transmissive electrode. When the first electrode 11 is a transmissive electrode, a material for forming the first electrode 11 may be indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO.sub.2), zinc oxide (ZnO), and any combinations thereof, but embodiments are not limited thereto. In one or more embodiments, when the first electrode 11 is a semi-transmissive electrode or a reflective electrode, a material for forming the first electrode 11 may be magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), magnesium-silver (Mg—Ag), and any combination thereof, but embodiments of the present disclosure are not limited thereto.

[0149] The first electrode 11 may have a single-layer structure or a multi-layer structure including multiple layers.

[0150] Emission Layer 15

[0151] The emission layer 15 may include the heterocyclic compound.

[0152] A thickness of the emission layer may be in a range of about 100 Å to about 1,000 Å, for example, about 200 Å to about 600 Å. When the thickness of the emission layer is within these ranges, excellent luminescence characteristics may be obtained without a substantial increase in driving voltage.

First Embodiment]—Description of FIG. 4A

[0153] In First Embodiment, the heterocyclic compound may be a fluorescence emitter. In First Embodiment, the emission layer may further include a host (hereinafter, referred to as ‘Host A’, and Host A is not identical to the heterocyclic compound). Host A may be understood by referring to the description of a host material below, but embodiments of the present disclosure are not limited thereto. Host A may be a fluorescent host.

[0154] General energy transfer in First Embodiment may be explained according to FIG. 4A.

[0155] Singlet excitons may be produced from Host A in the emission layer, and singlet excitons produced from Host A may be transferred to a fluorescence emitter through Förster energy transfer (FRET).

[0156] A ratio of singlet excitons produced from Host A may be 25%, and thus, 75% of triplet excitons produced from Host A may be fused to one another to be converted into singlet excitons. Thus, the efficiency of the organic light-emitting device may be further improved. That is, the efficiency of an organic light-emitting device may be further improved by using a triplet-triplet fusion mechanism.

[0157] In First Embodiment, a ratio of emission components emitted from the heterocyclic compound to the total emission components emitted from the emission layer may be equal to or greater than 80%, for example, equal to or greater than 90%. For example, a ratio of emission components emitted from the heterocyclic compound to the total emission components emitted from the emission layer may be equal to or greater than 95%.

[0158] The heterocyclic compound may emit fluorescence, and the host may not emit light.

[0159] In First Embodiment, when the emission layer further includes Host A, in addition to the heterocyclic compound, a content of the heterocyclic compound may be, based on 100 parts by weight of the emission layer, less than or equal to about 50 parts by weight, for example, less than or equal to about 30 parts by weight or less, and a content of Host A in the emission layer may be, based on 100 parts by weight of the emission layer, equal to or greater than about 50 parts by weight, for example, equal to or greater than about 70 parts by weight. However, embodiments of the present disclosure are not limited thereto.

[0160] In First Embodiment, when the emission layer further includes Host A, in addition to the heterocyclic compound, Host A and the heterocyclic compound may satisfy Condition A.

E(H.sub.A).sub.S1>E.sub.S1  Condition A:

[0161] In Condition A, [0162] E(H.sub.A).sub.S1 indicates a lowest excited singlet energy level of Host A, and [0163] E.sub.S1 indicates a lowest excited singlet energy level of the heterocyclic compound.

[0164] In Condition A, E(H.sub.A).sub.S1 and E.sub.S1 may be evaluated by using a Gaussian according to the DFT method, wherein structure optimization is performed at a degree of B3LYP, and 6-31G(d,p)).

Second Embodiment—Description of FIG. 4B

[0165] In Second Embodiment, the heterocyclic compound may be a delayed fluorescence emitter. In Second Embodiment, the emission layer may further include a host (hereinafter, referred to as ‘Host B’, and Host B is not identical to the heterocyclic compound). Host B may be understood by referring to the description of a host material below, but embodiments of the present disclosure are not limited thereto.

[0166] General energy transfer in Second Embodiment may be explained according to FIG. 4B.

[0167] 25% of singlet excitons produced from Host B in the emission layer may be transferred to a delayed fluorescence emitter through FRET. In addition, 75% of triplet excitons produced from Host B in the emission layer may be transferred to a delayed fluorescence emitter through Dexter energy transfer. Energy transferred to a triplet state of a delayed fluorescence emitter may undergo RISC to a singlet state. Accordingly, by transferring all the singlet excitons and triplet excitons generated in the emission layer to the heterocyclic compound, an organic light-emitting device including the heterocyclic compound and having improved efficiency may be obtained.

[0168] In Second Embodiment, a ratio of emission components emitted from the heterocyclic compound to the total emission components emitted from the emission layer may be equal to or greater than about 80%, for example, equal to or greater than about 90%. For example, a ratio of emission components emitted from the heterocyclic compound to the total emission components emitted from the emission layer may be equal to or greater than about 95%.

[0169] Here, the heterocyclic compound may emit fluorescence and/or delayed fluorescence, and the emission components of the heterocyclic compound may be a total of prompt emission components of the heterocyclic compound and delayed fluorescence components by RISC of the heterocyclic compound. In addition, Host B may not emit light.

[0170] In Second Embodiment, when the emission layer further includes Host B, in addition to the heterocyclic compound, a content of the heterocyclic compound may be, based on 100 parts by weight of the emission layer, less than or equal to about 50 parts by weight, for example, less than or equal to about 30 parts by weight or less, and a content of Host B in the emission layer may be, based on 100 parts by weight of the emission layer, equal to or greater than about 50 parts by weight, for example, equal to or greater than about 70 parts by weight. However, embodiments of the present disclosure are not limited thereto.

[0171] In Second Embodiment, when the emission layer further includes Host B, in addition to the heterocyclic compound, Host B and the heterocyclic compound may satisfy Condition B.

E(H.sub.B).sub.S1>E.sub.S1  Condition B:

[0172] In Condition B, [0173] E(H.sub.B).sub.S1 indicates a lowest excited singlet energy level of Host B, and [0174] E.sub.S1 indicates a lowest excited singlet energy level of the heterocyclic compound.

[0175] In Condition B, E(H.sub.A).sub.S1 and E.sub.S1 may be evaluated by using a Gaussian according to the DFT method, wherein structure optimization is performed at a degree of B3LYP, and 6-31G(d,p)).

Third Embodiment and Fourth Embodiment

Third Embodiment—Description of FIG. 4C

[0176] In Third Embodiment, the heterocyclic compound may be used as a fluorescence emitter, and the emission layer may include a sensitizer, e.g., a delayed fluorescence sensitizer. In Third Embodiment, the emission layer may further include a host (hereinafter, the host may be referred to as ‘Host C’, and Host C is not identical to the heterocyclic compound and the sensitizer) and a sensitizer (hereinafter, the sensitizer may be referred to as ‘Sensitizer A’, and Sensitizer A is not identical to Host C and the heterocyclic compound). Host C and Sensitizer A may respectively be understood by referring to the description of a host material and a sensitizer material below, but embodiments of the present disclosure are not limited thereto.

[0177] In Third Embodiment, a ratio of emission components of the heterocyclic compound to the total emission components emitted from the emission layer may be equal to or greater than about 80%, for example, equal to or greater than about 90% (or for example, equal to or greater than about 95%). For example, the heterocyclic compound may emit fluorescence. In addition, Host C and Sensitizer A may not each emit light.

[0178] General energy transfer in Third Embodiment may be explained according to FIG. 4C.

[0179] Singlet and triplet excitons may be produced from Host C in the emission layer, and singlet and triplet excitons produced from Host C may be transferred to Sensitizer A and then to the heterocyclic compound through FRET. 25% of singlet excitons produced from Host C may be transferred to Sensitizer A through FRET, and energy of 75% of triplet excitons produced from Host C may be transferred to singlet and triplet states of Sensitizer A. Energy transferred to a triplet state of Sensitizer A may undergo RISC to a singlet state, and then, singlet energy of Sensitizer A may be transferred to the heterocyclic compound through FRET.

[0180] Accordingly, by transferring all the singlet excitons and triplet excitons generated in the emission layer to the dopant, an organic light-emitting device having improved efficiency may be obtained. In addition, since an organic light-emitting device may be obtained with significantly reduced energy loss, the lifespan characteristics of the organic light-emitting device may be also improved.

[0181] In Third Embodiment, when the emission layer further includes Host C and Sensitizer A, in addition to the heterocyclic compound, Host C and Sensitizer A may satisfy Condition C-1 and/or C-2.

S.sub.1(H.sub.C)≥S.sub.1(S.sub.A)  Condition C-1:

S.sub.1(S.sub.A)≥S.sub.1(HC)  Condition C-2:

[0182] In Conditions C-1 and C-2, [0183] S.sub.1(H.sub.C) indicates a lowest excited singlet energy level of Host C, [0184] S.sub.1(S.sub.A) indicates a lowest excited singlet energy level of Sensitizer A, and [0185] S.sub.1(HC) indicates a lowest excited singlet energy level of the heterocyclic compound.

[0186] S.sub.1(H.sub.C), S.sub.1(S.sub.A), and S.sub.1(HC) may be evaluated by using a Gaussian according to the DFT method, wherein structure optimization is performed at a degree of B3LYP, and 6-31G(d,p)).

[0187] When Host C, Sensitizer A, and the heterocyclic compound satisfy Condition C-1 and/or C-2, FRET from Sensitizer A to the heterocyclic compound may be facilitated, and accordingly, the organic light-emitting device may have improved luminescence efficiency.

Fourth Embodiment—Description of FIG. 4D

[0188] In Fourth Embodiment, the heterocyclic compound may be used as a fluorescence emitter, and the emission layer may include a sensitizer, e.g., a phosphorescence sensitizer. In Fourth Embodiment, the emission layer may further include a host (hereinafter, the host may be referred to as ‘Host D’, and Host D is not identical to the heterocyclic compound and the sensitizer) and a sensitizer (hereinafter, the sensitizer may be referred to as ‘Sensitizer B’, and Sensitizer B is not identical to Host D and the heterocyclic compound). Host D and Sensitizer B may respectively be understood by referring to the description of a host material and a sensitizer material below, but embodiments of the present disclosure are not limited thereto.

[0189] In Fourth Embodiment, a ratio of emission components of the heterocyclic compound to the total emission components emitted from the emission layer may be equal to or greater than about 80%, for example, equal to or greater than about 90% (or for example, equal to or greater than about 95%). For example, the heterocyclic compound may emit fluorescence. In addition, Host D and Sensitizer B may not each emit light.

[0190] General energy transfer in Fourth Embodiment may be explained according to FIG. 4D.

[0191] 75% of triplet excitons produced from Host D in the emission layer may be transferred to Sensitizer B through Dexter energy transfer, and energy of 25% of singlet excitons produced from Host D may be transferred to singlet and triplet states of Sensitizer B. Energy transferred to a singlet state of Sensitizer B may undergo ISC to a triplet state, and then, triplet energy of Sensitizer B may be transferred to the heterocyclic compound through FRET.

[0192] Accordingly, by transferring all the singlet excitons and triplet excitons generated in the emission layer to the dopant, an organic light-emitting device having improved efficiency may be obtained. In addition, since an organic light-emitting device may be obtained with significantly reduced energy loss, the lifespan characteristics of the organic light-emitting device may be also improved.

[0193] In Fourth Embodiment, when the emission layer further includes Host D and Sensitizer B, in addition to the heterocyclic compound, Host D and Sensitizer B may satisfy Condition D-1 and/or D-2.

T.sub.1(H.sub.D)≥T.sub.1(S.sub.B)  Condition D-1:

T.sub.1(S.sub.B)≥S.sub.1(HC)  Condition D-2:

[0194] In Conditions D-1 and D-2, [0195] T.sub.1(H.sub.D) indicates a lowest excited triplet energy level of Host D, [0196] T.sub.1(S.sub.B) indicates a lowest excited triplet energy level of Sensitizer B, and [0197] S.sub.1(HC) indicates a lowest excited singlet energy level of the heterocyclic compound.

[0198] T.sub.1(Ho), T.sub.1(S.sub.B), and S.sub.1(HC) may be evaluated by using a Gaussian according to the DFT method, wherein structure optimization is performed at a degree of B3LYP, and 6-31G(d,p)).

[0199] When Host D, Sensitizer B, and the heterocyclic compound satisfy Condition D-1 and/or D-2, FRET from Sensitizer B to the heterocyclic compound may be facilitated, and accordingly, an organic light-emitting device including the heterocyclic compound may have improved luminescence efficiency.

[0200] In Third Embodiment and Fourth Embodiment, a content of the sensitizer in the emission layer may be in a range of about 5 wt % to about 50 wt %, or for example, about 10 wt % to about 30 wt %. When the content is within these ranges, effective energy transfer in the emission layer may be achieved. Thus, an organic light-emitting device including the heterocyclic compound may have high efficiency and a long lifespan.

[0201] In Third Embodiment and Fourth Embodiment, a content of the heterocyclic compound in the emission layer may be in a range of about 0.01 wt % to about 15 wt %, for example, about 0.05 wt % to about 3 wt %, but embodiments of the present disclosure are not limited thereto.

[0202] In Third Embodiment and Fourth Embodiment, the sensitizer and the heterocyclic compound may further satisfy Condition 5.

0 μs<T.sub.decay(HC)<5 μs  Condition 5:

[0203] In Condition 5, T.sub.decay(HC) indicates a decay time of the heterocyclic compound.

[0204] The decay time of the heterocyclic compound was measured from a time-resolved photoluminescence (TRPL) spectrum at room temperature of a film (hereinafter, referred to as “Film (HC)”) having a thickness of 40 nm formed by vacuum-depositing the host and the heterocyclic compound included in the emission layer on a quartz substrate at a weight ratio of 90:10 at a vacuum pressure of 10-7 torr.

Fifth Embodiment—Description of FIG. 4E

[0205] In Fifth Embodiment, the heterocyclic compound may be used as a delayed fluorescence emitter, and the emission layer may include a sensitizer, e.g., a delayed fluorescence sensitizer. In Fifth Embodiment, the emission layer may further include a host (hereinafter, the host may be referred to as ‘Host E’, and Host E is not identical to the heterocyclic compound and the sensitizer) and a sensitizer (hereinafter, the sensitizer may be referred to as ‘Sensitizer C’, and Sensitizer C is not identical to Host E and the heterocyclic compound). Host E and Sensitizer C may respectively be understood by referring to the description of a host material and a sensitizer material below, but embodiments of the present disclosure are not limited thereto.

[0206] In Fifth Embodiment, a ratio of emission components of the heterocyclic compound to the total emission components emitted from the emission layer may be equal to or greater than about 80%, for example, equal to or greater than about % (or for example, equal to or greater than about 95%). For example, the heterocyclic compound may emit fluorescence and/or delayed fluorescence. In addition, Host E and Sensitizer C may not each emit light.

[0207] Here, the heterocyclic compound may emit fluorescence and/or delayed fluorescence, and the emission components of the heterocyclic compound may be a total of prompt emission components of the heterocyclic compound and delayed fluorescence components by RISC of the heterocyclic compound.

[0208] General energy transfer in Fifth Embodiment may be explained according to FIG. 4E.

[0209] 25% of singlet excitons produced from Host E in the emission layer may be transferred to a singlet state of Sensitizer C through FRET, and energy of 75% of triplet excitons produced from Host E may be transferred to a triplet state of Sensitizer C, and then singlet energy of Sensitizer C may be transferred to the heterocyclic compound through FRET. Subsequently, the triplet energy of Sensitizer C may be transferred to the heterocyclic compound through Dexter energy transfer. Energy transferred to a triplet state of Sensitizer C may undergo RISC to a singlet state. Further, in a case of Sensitizer C, energy of triplet excitons produced from Sensitizer C may undergo reverse transfer to Host E and then to the heterocyclic compound, thus emitting by reverse intersystem transfer.

[0210] Accordingly, by transferring all the singlet excitons and triplet excitons generated in the emission layer to the dopant, an organic light-emitting device having improved efficiency may be obtained. In addition, since an organic light-emitting device may be obtained with significantly reduced energy loss, the lifespan characteristics of the organic light-emitting device may be also improved.

[0211] In Fifth Embodiment, when the emission layer further includes Host E and Sensitizer C, in addition to the heterocyclic compound, Host E and Sensitizer C may satisfy Condition E-1, E-2, and/or E-3.

S.sub.1(H.sub.E)≥S.sub.1(S.sub.C)  Condition E-1:

S.sub.1(S.sub.C)≥S.sub.1(HC)  Condition E-2:

T.sub.1(S.sub.C)≥T.sub.1(HC)  Condition E-3:

[0212] In Conditions E-1, E-2, and E-3, [0213] S.sub.1(H.sub.E) indicates a lowest excited singlet energy level of Host E, [0214] S.sub.1(S.sub.C) indicates a lowest excited singlet energy level of Sensitizer C, [0215] S.sub.1(HC) indicates the lowest excited singlet energy level of the heterocyclic compound, [0216] T.sub.1(S.sub.C) indicates a lowest excited triplet energy level of Sensitizer C, and [0217] T.sub.1(HC) indicates a lowest excited triplet energy level of the heterocyclic compound. [0218] S1(HE), S.sub.1(S.sub.C), S.sub.1(HC), T.sub.1(S.sub.C), and T.sub.1(HC may be evaluated by using a Gaussian according to the DFT method, wherein structure optimization is performed at a degree of B3LYP, and 6-31G(d,p)).

[0219] When Host E, Sensitizer C, and the heterocyclic compound satisfy Condition E-1, E-2, and/or E-3, Dexter transfer FRET from Sensitizer C to the heterocyclic compound may be facilitated, and accordingly, tan organic light-emitting device including the heterocyclic compound may have improved luminescence efficiency.

[0220] In Fifth Embodiment, a content of Sensitizer C in the emission layer may be in a range of about 5 wt % to about 50 wt %, or for example, about 10 wt % to about 30 wt %. When the content is within these ranges, effective energy transfer in the emission layer may be achieved. Thus, an organic light-emitting device including the heterocyclic compound may have high efficiency and a long lifespan.

[0221] In Fifth Embodiment, a content of the heterocyclic compound in the emission layer may be in a range of about 0.01 wt % to about 15 wt %, or for example, about 0.05 wt % to about 3 wt %, but embodiments of the present disclosure are not limited thereto.

[0222] Host in Emission Layer 15

[0223] The host may not include a metal atom.

[0224] In an embodiment, the host may include one kind of host. When the host includes one kind of host, the one kind of host may be a bipolar host, an electron-transporting host, or a hole-transporting host, which will be described later.

[0225] In one or more embodiments, the host may include a mixture of two or more different hosts. For example, the host may be a mixture of an electron-transporting host and a hole-transporting host, a mixture of two types of electron-transporting hosts different from each other, or a mixture of two types of hole-transporting hosts different from each other. The electron-transporting host and the hole-transporting host may be understood by referring to the related description to be presented later.

[0226] In one or more embodiments, the host may include an electron-transporting host including at least one electron-transporting moiety and a hole-transporting host that is free of an electron-transporting moiety.

[0227] The electron-transporting moiety used herein may be a cyano group, a π electron-deficient nitrogen-containing cyclic group, and a group represented by one of the following formulae:

##STR00589##

wherein, in the formulae above, *, *′, and *″ each indicate a binding site to a neighboring atom.

[0228] In an embodiment, the electron-transporting host in the emission layer 15 may include at least one of a cyano group, a π electron-deficient nitrogen-containing cyclic group, or a combination thereof.

[0229] In one or more embodiments, the electron-transporting host in the emission layer 15 may include at least one cyano group.

[0230] In one or more embodiments, the electron-transporting host in the emission layer 15 may include at least one cyano group, at least one π electron deficient nitrogen-containing cyclic group, or a combination thereof.

[0231] In one or more embodiments, the host may include an electron-transporting host and a hole-transporting host, wherein the electron-transporting host may include at least one π electron-deficient nitrogen-free cyclic group, at least one electron-transporting moiety, or a combination thereof, and the hole-transporting host may include at least one π electron-deficient nitrogen-free cyclic group and may not include an electron-transporting moiety.

[0232] The term “π electron-deficient nitrogen-containing cyclic group” as used herein refers to a cyclic group having at least one *—N═*′ moiety, and for example, may be an imidazole group, a pyrazole group, a thiazole group, an isothiazole group, an oxazole group, an isoxazole group, a pyridine group, a pyrazine group, a pyridazine group, a pyrimidine group, an indazole group, a purine group, a quinoline group, an isoquinoline group, a benzoquinoline group, a phthalazine group, a naphthyridine group, a quinoxaline group, a quinazoline group, a cinnoline group, a phenanthridine group, an acridine group, a phenanthroline group, a phenazine group, a benzimidazole group, an isobenzothiazole group, a benzoxazole group, an isobenzoxazole group, a triazole group, a tetrazole group, an oxadiazole group, a triazine group, a thiadiazole group, an imidazopyridine group, an imidazopyrimidine group, an azacarbazole group; or a condensed cyclic group in which two or more π electron-efficient nitrogen-containing cyclic groups are condensed with each other.

[0233] Meanwhile, the π electron-deficient nitrogen-free cyclic group may be a benzene group, a heptalene group, an indene group, a naphthalene group, an azulene group, an indacene group, an acenaphthylene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pentacene group, a hexacene group, a pentacene group, a rubicene group, a coragen group, an ovalene group, a pyrrole group, an isoindole group, an indole group, a furan group, a thiophene group, a benzofuran group, a benzothiophene group, a benzocarbazole group, a dibenzocarbazole group, a dibenzofuran group, a dibenzothiophene group, a dibenzothiophene sulfone group, a carbazole group, a dibenzosilole group, an indenocarbazole group, an indolocarbazole group, a benzofurocarbazole group, a benzothienocarbazole group, a triindolobenzene group, or a condensed cyclic group of two or more π electron-deficient nitrogen-free cyclic groups, but embodiments of the present disclosure are not limited thereto.

[0234] In one or more embodiments, the electron-transporting host may be a compound represented by Formula E-1, and [0235] the hole-transporting host may be compounds represented by Formula H-1, but embodiments of the present disclosure are not limited thereto:

[Ar.sub.301].sub.xb11-[(L.sub.301).sub.xb1-R.sub.301].sub.xb21  Formula E-1 [0236] wherein, in Formula E-1, [0237] Ar.sub.301 may be a substituted or unsubstituted C.sub.5-C.sub.60 carbocyclic group and a substituted or unsubstituted C.sub.1-C.sub.60 heterocyclic group, [0238] xb11 may be 1, 2, or 3, [0239] L.sub.301 may each independently be a single bond, groups represented by one of following formulae, a substituted or unsubstituted C.sub.5-C.sub.60 carbocyclic group, and a substituted or unsubstituted C.sub.1-C.sub.60 heterocyclic group, wherein in the following formulae, *′, and *″ may each indicate a binding site to an adjacent atom,

##STR00590## [0240] xb1 may be an integer from 1 to 5, [0241] R.sub.301 may be hydrogen, deuterium, —F, —Cl, —Br, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a substituted or unsubstituted C.sub.1-C.sub.60 alkyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkenyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkynyl group, a substituted or unsubstituted C.sub.1-C.sub.60 alkoxy group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted heterocycloalkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenyl group, a substituted or unsubstituted C.sub.2-C.sub.10 heterocycloalkenyl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryloxy group, a substituted or unsubstituted C.sub.6-C.sub.60 arylthio group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryl group, a substituted or unsubstituted monovalent aromatic condensed heteropolycyclic group, a substituted or unsubstituted monovalent aromatic condensed heteropolycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q.sub.301)(Q.sub.302)(Q.sub.303), —N(Q.sub.301)(Q.sub.302), —B(Q.sub.301)(Q.sub.302), —C(═O)(Q.sub.301), —S(═O).sub.2(Q.sub.301), —S(═O)(Q.sub.301), —P(═O)(Q.sub.301)(Q.sub.302), or —P(═S)(Q.sub.301)(Q.sub.302), [0242] xb21 may be an integer from 1 to 5, [0243] Q.sub.301 to Q.sub.303 may each independently be a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, or a naphthyl group, and [0244] at least one of Condition H-1 to Condition H-3 may be satisfied.

[0245] Condition H-1: at least one of Ar.sub.301, L.sub.301, and R.sub.301 in Formula E-1 each independently includes a π electron-depleted nitrogen-containing cyclic group;

[0246] Condition H-2: L.sub.301 in Formula E-1 is a group represented by one of the following formulae; and

##STR00591##

[0247] Condition H-3: R.sub.301 in Formula E-1 is a cyano group, —S(═O).sub.2(Q.sub.301), —S(═O)(Q.sub.301), —P(═O)(Q.sub.301)(Q.sub.302), and —P(═S)(Q.sub.301)(Q.sub.302),

##STR00592## [0248] wherein, in Formulae H-1, 11, and 12, [0249] L.sub.401 may be: [0250] a single bond; or [0251] a benzene group, a heptalene group, an indene group, a naphthalene group, an azulene group, an indacene group, an acenaphthylene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pentacene group, a hexacene group, a pentacene group, a rubicene group, a coragen group, an ovalene group, a pyrrole group, an isoindole group, an indole group, a furan group, a thiophene group, a benzofuran group, a benzothiophene group, a benzocarbazole group, a dibenzocarbazole group, a dibenzofuran group, a dibenzothiophene group, a dibenzothiophene sulfone group, a carbazole group, a dibenzosilole group, an indenocarbazole group, an indolocarbazole group, a benzofurocarbazole group, a benzothienocarbazole group, or a triindolobenzene group, each unsubstituted or substituted with at least one deuterium, a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group, a phenyl group, a naphthyl group, a fluorenyl group, a carbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a triphenylenyl group, a biphenyl group, a terphenyl group, a tetraphenyl group, —Si(Q.sub.401)(Q.sub.402)(Q.sub.403), or a combination thereof, [0252] xd1 may be an integer from 1 to 10, wherein, when xd1 is 2 or greater, two or more of L.sub.401 may be identical to or different from each other, [0253] Ar.sub.401 may be a group represented by Formula 11 or 12, [0254] Ar.sub.402 may be: [0255] a group represented by Formula 11 or 12, a phenyl group, a naphthyl group, a fluorenyl group, a carbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a biphenyl group, a terphenyl group, or a triphenylenyl group; or [0256] a phenyl group, a naphthyl group, a fluorenyl group, a carbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a biphenyl group, a terphenyl group, or a triphenylenyl group, each substituted with at least one deuterium, a hydroxyl group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid or a salt thereof, a sulfonic acid or a salt thereof, a phosphoric acid or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a naphthyl group, a fluorenyl group, a carbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a biphenyl group, a terphenyl group, a triphenylenyl group, or a combination thereof, [0257] CY.sub.401 and CY.sub.402 may each independently be a benzene group, a naphthalene group, a fluorene group, a carbazole group, a benzocarbazole group, an indolocarbazole group, a dibenzofuran group, a dibenzothiophene group, a dibenzosilole group, a benzonaphthofuran group, a benzonapthothiophene group, or a benzonaphthosilole group, [0258] A.sub.21 may be a single bond, O, S, N(R.sub.51), C(R.sub.51)(R.sub.52), or Si(R.sub.51)(R.sub.52), [0259] A.sub.22 may be a single bond, O, S, N(R.sub.53), C(R.sub.53)(R.sub.54), or Si(R.sub.53)(R.sub.54), [0260] at least one of A.sub.21 and A.sub.22 in Formula 12 may not be a single bond, [0261] R.sub.51 to R.sub.54, R.sub.60, and R.sub.70 may each independently be: [0262] hydrogen, deuterium, a hydroxyl group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, or a C.sub.1-C.sub.20 alkoxy group; [0263] a C.sub.1-C.sub.20 alkyl group and a C.sub.1-C.sub.20 alkoxy group, each substituted with at least one deuterium, a hydroxyl group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a phenyl group, a naphthyl group, a fluorenyl group, a carbazolyl group, a dibenzofuranyl group, or a dibenzothiophenyl group; [0264] a π electron-depleted nitrogen-free cyclic group (e.g., a phenyl group, a naphthyl group, a fluorenyl group, a carbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a biphenyl group, a terphenyl group, and a triphenylenyl group); [0265] a π electron-depleted nitrogen-free cyclic group (e.g., a phenyl group, a naphthyl group, a fluorenyl group, a carbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a biphenyl group, a terphenyl group, and a triphenylenyl group) substituted with at least one deuterium, a hydroxyl group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a naphthyl group, a fluorenyl group, a carbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a biphenyl group, or a combination thereof,

—Si(Q.sub.404)(Q.sub.405)(Q.sub.406), [0266] e1 and e2 may each independently be an integer from 0 to 10, [0267] Q.sub.401 to Q.sub.406 may each independently be hydrogen, deuterium, a hydroxyl group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a phenyl group, a naphthyl group, a fluorenyl group, a carbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a biphenyl group, a terphenyl group, or a triphenylenyl group, and [0268] * indicates a binding site to a neighboring atom.

[0269] In an embodiment, in Formula E-1, Ar.sub.301 and L.sub.301 may each independently be a benzene group, a naphthalene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pentaphene group, an indenoanthracene group, a dibenzofuran group, a dibenzothiophene group, an imidazole group, a pyrazole group, a thiazole group, an isothiazole group, an oxazole group, an isoxazole group, a pyridine group, a pyrazine group, a pyridazine group, a pyrimidine group, an indazole group, a purine group, a quinoline group, an isoquinoline group, a benzoquinoline group, a phthalazine group, a naphthyridine group, a quinoxaline group, a quinazoline group, a cinnoline group, a phenanthridine group, an acridine group, a phenanthroline group, a phenazine group, a benzimidazole group, an isobenzothiazole group, a benzoxazole group, an isobenzoxazole group, a triazole group, a tetrazole group, an oxadiazole group, a triazine group, a thiadiazole group, an imidazopyridine group, an imidazopyrimidine group, or an azacarbazole group, each unsubstituted or substituted with at least one deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a cyano group-containing phenyl group, a cyano group-containing biphenyl group, a cyano group-containing terphenyl group, a cyano group-containing naphthyl group, a pyridinyl group, a phenylpyridinyl group, a diphenylpyridinyl group, a biphenylpyridinyl group, a di(biphenyl)pyridinyl group, a pyrazinyl group, a phenylpyrazinyl group, a diphenylpyrazinyl group, a biphenylpyrazinyl group, a di(biphenyl)pyrazinyl group, a pyridazinyl group, a phenylpyridazinyl group, a diphenylpyridazinyl group, a biphenylpyridazinyl group, a di(biphenyl)pyridazinyl group, a pyrimidinyl group, a phenylpyrimidinyl group, a diphenylpyrimidinyl group, a biphenylpyrimidinyl group, a di(biphenyl)pyrimidinyl group, a triazinyl group, a phenyltriazinyl group, a diphenyltriazinyl group, a biphenyltriazinyl group, a di(biphenyl)triazinyl group, —Si(Q.sub.31)(Q.sub.32)(Q.sub.33), —N(Q.sub.31)(Q.sub.32), —B(Q.sub.31)(Q.sub.32), —C(═O)(Q.sub.31), —S(═O).sub.2(Q.sub.31), —P(═O)(Q.sub.31)(Q.sub.32), or a combination thereof, at least one of L.sub.301(s) in the number of xb1 may each independently be an imidazole group, a pyrazole group, a thiazole group, an isothiazole group, an oxazole group, an isoxazole group, a pyridine group, a pyrazine group, a pyridazine group, a pyrimidine group, an indazole group, a purine group, a quinoline group, an isoquinoline group, a benzoquinoline group, a phthalazine group, a naphthyridine group, a quinoxaline group, a quinazoline group, a cinnoline group, a phenanthridine group, an acridine group, a phenanthroline group, a phenazine group, a benzimidazole group, an isobenzothiazole group, a benzoxazole group, an isobenzoxazole group, a triazole group, a tetrazole group, an oxadiazole group, a triazine group, a thiadiazole group, an imidazopyridine group, an imidazopyrimidine group, or an azacarbazole group, each unsubstituted or substituted with at least one deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a cyano-containing phenyl group, a cyano-containing biphenyl group, a cyano-containing terphenyl group, a cyano-containing naphthyl group, a pyridinyl group, a phenylpyridinyl group, a diphenylpyridinyl group, a biphenylpyridinyl group, a di(biphenyl)pyridinyl group, a pyrazinyl group, a phenylpyrazinyl group, a diphenylpyrazinyl group, a biphenylpyrazinyl group, a di(biphenyl)pyrazinyl group, a pyridazinyl group, a phenylpyridazinyl group, a diphenylpyridazinyl group, a biphenylpyridazinyl group, a di(biphenyl)pyridazinyl group, a pyrimidinyl group, a phenylpyrimidinyl group, a diphenylpyrimidinyl group, a biphenylpyrimidinyl group, a di(biphenyl)pyrimidinyl group, a triazinyl group, a phenyltriazinyl group, a diphenyltriazinyl group, a biphenyltriazinyl group, a di(biphenyl)triazinyl group, —Si(Q.sub.31)(Q.sub.32)(Q.sub.33), —N(Q.sub.31)(Q.sub.32), —B(Q.sub.31)(Q.sub.32), —C(═O)(Q.sub.31), —S(═O).sub.2(Q.sub.31), —P(═O)(Q.sub.31)(Q.sub.32), or a combination thereof, and [0270] R.sub.301 may be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a tetraphenyl group, a naphthyl group, a cyano group-containing phenyl group, a cyano group-containing biphenyl group, a cyano group-containing terphenyl group, a cyano group-containing tetraphenyl group, a cyano group-containing naphthyl group, a pyridinyl group, a phenylpyridinyl group, a diphenylpyridinyl group, a biphenylpyridinyl group, a di(biphenyl)pyridinyl group, a pyrazinyl group, a phenylpyrazinyl group, a diphenylpyrazinyl group, a biphenylpyrazinyl group, a di(biphenyl)pyrazinyl group, a pyridazinyl group, a phenylpyridazinyl group, a diphenylpyridazinyl group, a biphenylpyridazinyl group, a di(biphenyl)pyridazinyl group, a pyrimidinyl group, a phenylpyrimidinyl group, a diphenylpyrimidinyl group, a biphenylpyrimidinyl group, a di(biphenyl)pyrimidinyl group, a triazinyl group, a phenyltriazinyl group, a diphenyltriazinyl group, a biphenyltriazinyl group, a di(biphenyl)triazinyl group, —Si(Q.sub.31)(Q.sub.32)(Q.sub.33), —N(Q.sub.31)(Q.sub.32), —B(Q.sub.31)(Q.sub.32), —C(═O)(Q.sub.31), —S(═O).sub.2(Q.sub.31), or —P(═O)(Q.sub.31)(Q.sub.32), and [0271] Q.sub.31 to Q.sub.33 may each independently be a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, or a naphthyl group, but embodiments of the present disclosure are not limited thereto.

[0272] In one or more embodiments, [0273] Ar.sub.301 may be a benzene group, a naphthalene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pentaphene group, an indenoanthracene group, a dibenzofuran group, or a dibenzothiophene group, each unsubstituted or substituted with at least one deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a cyano-containing phenyl group, a cyano-containing biphenyl group, a cyano-containing terphenyl group, a cyano-containing naphthyl group, a pyridinyl group, a phenylpyridinyl group, a diphenylpyridinyl group, a biphenylpyridinyl group, a di(biphenyl)pyridinyl group, a pyrazinyl group, a phenylpyrazinyl group, a diphenylpyrazinyl group, a biphenylpyrazinyl group, a di(biphenyl)pyrazinyl group, a pyridazinyl group, a phenylpyridazinyl group, a diphenylpyridazinyl group, a biphenylpyridazinyl group, a di(biphenyl)pyridazinyl group, a pyrimidinyl group, a phenylpyrimidinyl group, a diphenylpyrimidinyl group, a biphenylpyrimidinyl group, a di(biphenyl)pyrimidinyl group, a triazinyl group, a phenyltriazinyl group, a diphenyltriazinyl group, a biphenyltriazinyl group, a di(biphenyl)triazinyl group, —Si(Q.sub.31)(Q.sub.32)(Q.sub.33), —N(Q.sub.31)(Q.sub.32), —B(Q.sub.31)(Q.sub.32), —C(═O)(Q.sub.31), —S(═O).sub.2(Q.sub.31), —P(═O)(Q.sub.31)(Q.sub.32), or a combination thereof; or [0274] a group represented by Formulae 5-1 to 5-3 and 6-1 to 6-33, and [0275] L.sub.301 may be a group represented by one of Formulae 5-1 to 5-3 and 6-1 to 6-33:

##STR00593## ##STR00594## ##STR00595## ##STR00596## [0276] wherein, in Formulae 5-1 to 5-3 and 6-1 to 6-33, [0277] Z.sub.1 may be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a cyano group-containing phenyl group, a cyano group-containing biphenyl group, a cyano group-containing terphenyl group, a cyano group-containing naphthyl group, a pyridinyl group, a phenylpyridinyl group, a diphenylpyridinyl group, a biphenylpyridinyl group, a di(biphenyl)pyridinyl group, a pyrazinyl group, a phenylpyrazinyl group, a diphenylpyrazinyl group, a biphenylpyrazinyl group, a di(biphenyl)pyrazinyl group, a pyridazinyl group, a phenylpyridazinyl group, a diphenylpyridazinyl group, a biphenylpyridazinyl group, a di(biphenyl)pyridazinyl group, a pyrimidinyl group, a phenylpyrimidinyl group, a diphenylpyrimidinyl group, a biphenylpyrimidinyl group, a di(biphenyl)pyrimidinyl group, a triazinyl group, a phenyltriazinyl group, a diphenyltriazinyl group, a biphenyltriazinyl group, a di(biphenyl)triazinyl group, —Si(Q.sub.31)(Q.sub.32)(Q.sub.33), —N(Q.sub.31)(Q.sub.32), —B(Q.sub.31)(Q.sub.32), —C(═O)(Q.sub.31), —S(═O).sub.2(Q.sub.31), or —P(═O)(Q.sub.31)(Q.sub.32), [0278] d4 may be 0, 1, 2, 3, or 4, [0279] d3 may be 0, 1, 2, or 3, [0280] d2 may be 0, 1, or 2, [0281] * and *1 each indicate a binding site to an adjacent atom.

[0282] Q.sub.31 to Q.sub.33 may each be the same as described in the present specification.

[0283] In one or more embodiments, L.sub.301 may be a group represented by one of Formulae 5-2, 5-3 and 6-8 to 6-33.

[0284] In one or more embodiments, R.sub.301 may be a cyano group or a group represented by Formula 7-1 to 7-18, and at least one of Ar.sub.402(s) in the number of xd11 may be a group represented by Formulae 7-1 to 7-18, but embodiments of the present disclosure are not limited thereto:

##STR00597## ##STR00598## ##STR00599## ##STR00600## [0285] wherein, in Formulae 7-1 to 7-18, [0286] xb41 to xb44 may each be 0, 1, or 2, provided that xb41 in Formula 7-10 may not be 0, xb41+xb42 in Formulae 7-11 to 7-13 may not be 0, xb41+xb42+xb43 in Formulae 7-14 to 7-16 may not be 0, xb41+xb42+xb43+xb44 in Formulae 7-17 and 7-18 may not be 0, and * indicates a binding site to an adjacent atom.

[0287] In Formula E-1, at least two Ar.sub.301(s) may be identical to or different from each other, and at least two L.sub.301 (s) may be identical to or different from each other. In Formula H-1, at least two L.sub.401(s) may be identical to or different from each other, and at least two Ar.sub.402(s) may be identical to or different from each other.

[0288] In an embodiment, the electron-transporting host includes i) at least one of a cyano group, a pyrimidine group, a pyrazine group, and a triazine group and ii) a triphenylene group, and the hole-transporting host may include a carbazole group.

[0289] In one or more embodiments, the electron-transporting host may include at least one cyano group.

[0290] The electron transporting host may be selected from, for example, compounds of Groups HE1 to HE7, but embodiments are not limited thereto:

##STR00601## ##STR00602## ##STR00603## ##STR00604## ##STR00605## ##STR00606## ##STR00607## ##STR00608## ##STR00609## ##STR00610## ##STR00611## ##STR00612## ##STR00613## ##STR00614## ##STR00615## ##STR00616## ##STR00617## ##STR00618## ##STR00619## ##STR00620## ##STR00621## ##STR00622## ##STR00623## ##STR00624## ##STR00625## ##STR00626## ##STR00627## ##STR00628## ##STR00629## ##STR00630## ##STR00631## ##STR00632## ##STR00633## ##STR00634## ##STR00635## ##STR00636## ##STR00637## ##STR00638## ##STR00639## ##STR00640## ##STR00641## ##STR00642## ##STR00643## ##STR00644## ##STR00645## ##STR00646## ##STR00647## ##STR00648## ##STR00649## ##STR00650## ##STR00651## ##STR00652## ##STR00653## ##STR00654## ##STR00655## ##STR00656## ##STR00657## ##STR00658## ##STR00659##

##STR00660## ##STR00661## ##STR00662## ##STR00663## ##STR00664## ##STR00665## ##STR00666## ##STR00667## ##STR00668## ##STR00669## ##STR00670## ##STR00671## ##STR00672## ##STR00673## ##STR00674## ##STR00675## ##STR00676## ##STR00677## ##STR00678## ##STR00679## ##STR00680## ##STR00681## ##STR00682## ##STR00683## ##STR00684## ##STR00685## ##STR00686## ##STR00687## ##STR00688## ##STR00689## ##STR00690## ##STR00691## ##STR00692## ##STR00693## ##STR00694## ##STR00695## ##STR00696## ##STR00697## ##STR00698## ##STR00699## ##STR00700## ##STR00701## ##STR00702## ##STR00703## ##STR00704## ##STR00705## ##STR00706## ##STR00707## ##STR00708## ##STR00709## ##STR00710## ##STR00711## ##STR00712## ##STR00713##

##STR00714## ##STR00715## ##STR00716## ##STR00717## ##STR00718## ##STR00719## ##STR00720## ##STR00721## ##STR00722## ##STR00723## ##STR00724## ##STR00725## ##STR00726## ##STR00727## ##STR00728## ##STR00729## ##STR00730## ##STR00731## ##STR00732## ##STR00733## ##STR00734## ##STR00735## ##STR00736## ##STR00737## ##STR00738## ##STR00739## ##STR00740## ##STR00741## ##STR00742## ##STR00743## ##STR00744## ##STR00745## ##STR00746## ##STR00747## ##STR00748## ##STR00749## ##STR00750## ##STR00751## ##STR00752## ##STR00753## ##STR00754## ##STR00755## ##STR00756## ##STR00757## ##STR00758## ##STR00759## ##STR00760## ##STR00761## ##STR00762## ##STR00763## ##STR00764## ##STR00765## ##STR00766## ##STR00767## ##STR00768## ##STR00769## ##STR00770## ##STR00771## ##STR00772## ##STR00773## ##STR00774## ##STR00775## ##STR00776## ##STR00777## ##STR00778## ##STR00779## ##STR00780## ##STR00781## ##STR00782## ##STR00783## ##STR00784##

##STR00785## ##STR00786## ##STR00787## ##STR00788## ##STR00789## ##STR00790## ##STR00791## ##STR00792## ##STR00793## ##STR00794## ##STR00795## ##STR00796## ##STR00797## ##STR00798## ##STR00799## ##STR00800## ##STR00801## ##STR00802## ##STR00803## ##STR00804## ##STR00805## ##STR00806## ##STR00807## ##STR00808## ##STR00809## ##STR00810## ##STR00811## ##STR00812## ##STR00813## ##STR00814## ##STR00815## ##STR00816## ##STR00817## ##STR00818## ##STR00819## ##STR00820## ##STR00821## ##STR00822## ##STR00823## ##STR00824## ##STR00825## ##STR00826## ##STR00827## ##STR00828## ##STR00829## ##STR00830## ##STR00831## ##STR00832## ##STR00833## ##STR00834## ##STR00835## ##STR00836## ##STR00837## ##STR00838## ##STR00839## ##STR00840## ##STR00841## ##STR00842## ##STR00843## ##STR00844## ##STR00845## ##STR00846## ##STR00847##

##STR00848## ##STR00849## ##STR00850## ##STR00851## ##STR00852## ##STR00853## ##STR00854## ##STR00855## ##STR00856## ##STR00857## ##STR00858## ##STR00859## ##STR00860## ##STR00861## ##STR00862## ##STR00863## ##STR00864## ##STR00865## ##STR00866## ##STR00867## ##STR00868## ##STR00869## ##STR00870## ##STR00871## ##STR00872## ##STR00873## ##STR00874## ##STR00875## ##STR00876## ##STR00877## ##STR00878## ##STR00879## ##STR00880## ##STR00881## ##STR00882## ##STR00883## ##STR00884## ##STR00885## ##STR00886## ##STR00887## ##STR00888## ##STR00889## ##STR00890## ##STR00891## ##STR00892## ##STR00893## ##STR00894## ##STR00895## ##STR00896## ##STR00897## ##STR00898## ##STR00899## ##STR00900## ##STR00901## ##STR00902## ##STR00903## ##STR00904## ##STR00905## ##STR00906## ##STR00907## ##STR00908## ##STR00909## ##STR00910## ##STR00911## ##STR00912## ##STR00913## ##STR00914## ##STR00915## ##STR00916## ##STR00917## ##STR00918## ##STR00919## ##STR00920## ##STR00921## ##STR00922## ##STR00923##

##STR00924## ##STR00925## ##STR00926## ##STR00927## ##STR00928## ##STR00929## ##STR00930## ##STR00931## ##STR00932## ##STR00933## ##STR00934## ##STR00935## ##STR00936## ##STR00937## ##STR00938## ##STR00939## ##STR00940## ##STR00941## ##STR00942## ##STR00943## ##STR00944## ##STR00945## ##STR00946## ##STR00947## ##STR00948## ##STR00949## ##STR00950## ##STR00951## ##STR00952## ##STR00953## ##STR00954## ##STR00955## ##STR00956## ##STR00957## ##STR00958## ##STR00959## ##STR00960## ##STR00961## ##STR00962## ##STR00963## ##STR00964## ##STR00965## ##STR00966## ##STR00967## ##STR00968## ##STR00969## ##STR00970## ##STR00971## ##STR00972## ##STR00973## ##STR00974## ##STR00975## ##STR00976## ##STR00977## ##STR00978## ##STR00979## ##STR00980## ##STR00981## ##STR00982## ##STR00983## ##STR00984## ##STR00985## ##STR00986## ##STR00987## ##STR00988## ##STR00989##

##STR00990## ##STR00991## ##STR00992## ##STR00993## ##STR00994## ##STR00995## ##STR00996## ##STR00997## ##STR00998## ##STR00999## ##STR01000## ##STR01001## ##STR01002## ##STR01003## ##STR01004## ##STR01005## ##STR01006## ##STR01007## ##STR01008## ##STR01009## ##STR01010## ##STR01011## ##STR01012## ##STR01013## ##STR01014## ##STR01015## ##STR01016## ##STR01017## ##STR01018## ##STR01019## ##STR01020## ##STR01021## ##STR01022## ##STR01023## ##STR01024## ##STR01025## ##STR01026## ##STR01027## ##STR01028## ##STR01029## ##STR01030## ##STR01031## ##STR01032## ##STR01033## ##STR01034## ##STR01035## ##STR01036## ##STR01037## ##STR01038## ##STR01039## ##STR01040## ##STR01041## ##STR01042## ##STR01043## ##STR01044## ##STR01045## ##STR01046## ##STR01047## ##STR01048## ##STR01049## ##STR01050## ##STR01051## ##STR01052## ##STR01053## ##STR01054## ##STR01055## ##STR01056##

##STR01057## ##STR01058## ##STR01059## ##STR01060## ##STR01061## ##STR01062## ##STR01063## ##STR01064## ##STR01065## ##STR01066## ##STR01067## ##STR01068## ##STR01069## ##STR01070## ##STR01071## ##STR01072## ##STR01073## ##STR01074## ##STR01075## ##STR01076## ##STR01077## ##STR01078## ##STR01079## ##STR01080## ##STR01081## ##STR01082## ##STR01083## ##STR01084## ##STR01085## ##STR01086## ##STR01087## ##STR01088## ##STR01089## ##STR01090## ##STR01091## ##STR01092## ##STR01093## ##STR01094## ##STR01095## ##STR01096## ##STR01097## ##STR01098## ##STR01099## ##STR01100## ##STR01101## ##STR01102## ##STR01103## ##STR01104## ##STR01105## ##STR01106## ##STR01107## ##STR01108## ##STR01109## ##STR01110## ##STR01111## ##STR01112## ##STR01113## ##STR01114## ##STR01115## ##STR01116## ##STR01117## ##STR01118## ##STR01119## ##STR01120## ##STR01121## ##STR01122## ##STR01123## ##STR01124## ##STR01125##

##STR01126## ##STR01127## ##STR01128## ##STR01129## ##STR01130## ##STR01131## ##STR01132## ##STR01133## ##STR01134## ##STR01135## ##STR01136## ##STR01137## ##STR01138## ##STR01139## ##STR01140## ##STR01141## ##STR01142## ##STR01143## ##STR01144## ##STR01145## ##STR01146## ##STR01147## ##STR01148## ##STR01149## ##STR01150## ##STR01151## ##STR01152## ##STR01153## ##STR01154## ##STR01155## ##STR01156## ##STR01157## ##STR01158## ##STR01159## ##STR01160## ##STR01161## ##STR01162## ##STR01163## ##STR01164## ##STR01165## ##STR01166## ##STR01167## ##STR01168## ##STR01169## ##STR01170## ##STR01171## ##STR01172## ##STR01173## ##STR01174## ##STR01175## ##STR01176## ##STR01177## ##STR01178## ##STR01179##

##STR01180## ##STR01181## ##STR01182## ##STR01183## ##STR01184## ##STR01185## ##STR01186## ##STR01187## ##STR01188## ##STR01189## ##STR01190## ##STR01191## ##STR01192## ##STR01193## ##STR01194## ##STR01195## ##STR01196## ##STR01197## ##STR01198## ##STR01199## ##STR01200## ##STR01201## ##STR01202## ##STR01203## ##STR01204## ##STR01205## ##STR01206## ##STR01207## ##STR01208## ##STR01209## ##STR01210##

[0291] In one or more embodiments, the electron-transport host may include DPEPO and TSPO1:

##STR01211##

[0292] In one or more embodiments, the hole-transporting host may be compounds of Group HH1, but embodiments of the present disclosure are not limited thereto:

##STR01212## ##STR01213## ##STR01214## ##STR01215## ##STR01216## ##STR01217## ##STR01218## ##STR01219## ##STR01220## ##STR01221## ##STR01222## ##STR01223## ##STR01224## ##STR01225## ##STR01226## ##STR01227## ##STR01228## ##STR01229## ##STR01230## ##STR01231## ##STR01232## ##STR01233## ##STR01234## ##STR01235## ##STR01236## ##STR01237## ##STR01238## ##STR01239## ##STR01240## ##STR01241## ##STR01242## ##STR01243##

[0293] In one or more embodiments, the bipolar host may be compounds of Group HEH1, but embodiments are not limited thereto:

##STR01244## ##STR01245## ##STR01246## ##STR01247## ##STR01248## ##STR01249## ##STR01250## ##STR01251## ##STR01252## ##STR01253## ##STR01254## ##STR01255## ##STR01256## ##STR01257## ##STR01258## ##STR01259## ##STR01260## ##STR01261## ##STR01262## ##STR01263## ##STR01264## ##STR01265## ##STR01266## ##STR01267## ##STR01268## ##STR01269## ##STR01270## ##STR01271## ##STR01272## ##STR01273## ##STR01274## ##STR01275## ##STR01276## ##STR01277## ##STR01278## ##STR01279## ##STR01280## ##STR01281## ##STR01282## ##STR01283## ##STR01284## ##STR01285## ##STR01286## ##STR01287## ##STR01288## ##STR01289## ##STR01290## ##STR01291## ##STR01292## ##STR01293## ##STR01294## ##STR01295## ##STR01296## ##STR01297## ##STR01298## ##STR01299## ##STR01300## ##STR01301## ##STR01302## ##STR01303## ##STR01304## ##STR01305## ##STR01306## ##STR01307##

##STR01308## ##STR01309## ##STR01310## ##STR01311## ##STR01312## ##STR01313## ##STR01314## ##STR01315## ##STR01316## ##STR01317## ##STR01318## ##STR01319## ##STR01320## ##STR01321## ##STR01322## ##STR01323## ##STR01324## ##STR01325## ##STR01326## ##STR01327## ##STR01328## ##STR01329## ##STR01330## ##STR01331## ##STR01332## [0294] wherein, in Compounds 1 to 432, [0295] “Ph” represents a phenyl group.

[0296] In one or more embodiments, the hole-transporting host may include o-CBP or mCP:

##STR01333##

[0297] In an embodiment, the host may be a fluorescent host, and the fluorescent host may be represented by, for example, one of Formulae FH-1 to FH-4.

[0298] In an embodiment, the fluorescent host may be represented by Formula FH-1:

##STR01334## [0299] wherein, in Formula FH-1, [0300] Ar.sub.1 to Ar.sub.3 may each independently be a substituted or unsubstituted C.sub.1-C.sub.60 alkyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkenyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkynyl group, a substituted or unsubstituted C.sub.1-C.sub.60 alkoxy group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenyl group, a substituted or unsubstituted C.sub.2-C.sub.10 heterocycloalkenyl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryloxy group, a substituted or unsubstituted C.sub.6-C.sub.60 arylthio group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryl group, a substituted or unsubstituted C.sub.1-C.sub.60 hetero aryloxy group, a substituted or unsubstituted C.sub.1-C.sub.60 hetero arylthio group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q.sub.1)(Q.sub.2)(Q.sub.3), —N(Q.sub.1)(Q.sub.2), —B(Q.sub.1)(Q.sub.2), —C(═O)(Q.sub.1), —S(═O).sub.2(Q.sub.1), or —P(═O)(Q.sub.1)(Q.sub.2), [0301] at least one of Ar.sub.1 to Ar.sub.3 may each independently be a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, or a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, [0302] L.sub.10 may be an unsubstituted or substituted C.sub.5-C.sub.30 carbocyclic group or an unsubstituted or substituted C.sub.1-C.sub.30 heterocyclic group, [0303] a10 may be an integer from 1 to 3, wherein, when al is 2 or greater, two or more of L.sub.1 may be identical to or different from each other, [0304] R.sub.10 and R.sub.20 may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, —SF.sub.5, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C.sub.1-C.sub.60 alkyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkenyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkynyl group, a substituted or unsubstituted C.sub.1-C.sub.60 alkoxy group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenyl group, a substituted or unsubstituted C.sub.2-C.sub.10 heterocycloalkenyl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryloxy group, a substituted or unsubstituted C.sub.6-C.sub.60 arylthio group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —N(Q.sub.1)(Q.sub.2), —Si(Q.sub.3)(Q.sub.4)(Q.sub.5), —B(Q.sub.6)(Q.sub.7), or —P(═O)(Q.sub.8)(Q.sub.9), [0305] b10 and b20 may each independently an integer from 1 to 8, [0306] wherein, when b10 is 2 or greater, two or more of R.sub.10 may be identical to or different from each other, and when b20 is 2 or greater, two or more of R.sub.20 may be identical to or different from each other, and [0307] c10 may be an integer from 1 to 9, [0308] wherein, when c10 is 2 or greater, two or more of -[(L.sub.10).sub.a10-(R.sub.10).sub.b10] may be identical to or different from each other.

[0309] In an embodiment, the fluorescent host represented by Formula FH-1 may be a compound of Group FH1, but embodiments of the present disclosure are not limited thereto:

##STR01335## ##STR01336## ##STR01337## ##STR01338## ##STR01339## ##STR01340## ##STR01341## ##STR01342## ##STR01343## ##STR01344## ##STR01345## ##STR01346## ##STR01347## ##STR01348## ##STR01349## ##STR01350## ##STR01351## ##STR01352## ##STR01353##

[0310] In an embodiment, the fluorescent host may be represented by Formula FH-2:

##STR01354## [0311] wherein, in Formula FH-2, [0312] X.sub.1 may be O or S, [0313] A.sub.1 may be a C.sub.5-C.sub.60 carbocyclic group or a C.sub.1-C.sub.60 heterocyclic group, [0314] L.sub.11 may be an unsubstituted or substituted C.sub.5-C.sub.60 carbocyclic group or an unsubstituted or substituted C.sub.1-C.sub.60 heterocyclic group, [0315] a11 may be an integer from 0 to 3, [0316] Ar.sub.11 and Ar.sub.12 may each independently be a C.sub.6-C.sub.60 aryl group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, or a monovalent non-aromatic condensed heteropolycyclic group, each unsubstituted or substituted with at least one R.sub.a, [0317] b11 may be an integer from 1 to 5, [0318] R.sub.11, R.sub.12, and Ra may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C.sub.1-C.sub.60 alkyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkenyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkynyl group, a substituted or unsubstituted C.sub.1-C.sub.60 alkoxy group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenyl group, a substituted or unsubstituted C.sub.2-C.sub.10 heterocycloalkenyl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryloxy group, a substituted or unsubstituted C.sub.6-C.sub.60 arylthio group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q.sub.1)(Q.sub.2)(Q.sub.3), —N(Q.sub.4)(Q.sub.5), or —B(Q.sub.6)(Q.sub.7), [0319] c11 may be an integer from 1 to 20, [0320] c12 may be an integer from 1 to 4, [0321] when c11 is 2 or greater, two neighboring R.sub.11(s) may optionally be combined with each other to form a substituted or unsubstituted C.sub.5-C.sub.30 carbocyclic group or a substituted or unsubstituted C.sub.1-C.sub.30 heterocyclic group, [0322] when c12 is 2 or greater, two neighboring R.sub.12(s) may optionally be combined with each other to form a substituted or unsubstituted C.sub.5-C.sub.30 carbocyclic group or a substituted or unsubstituted C.sub.1-C.sub.30 heterocyclic group, [0323] A.sub.1 and Ar.sub.12 may optionally be linked to each other via a first linking group a single bond, *—Ar.sub.31-′, *—[C(R.sub.31)(R.sub.32)]k11-*′, *—C(R.sub.31)=*′, *═C(R.sub.31)—*′, *—C(R.sub.31)═C(R.sub.32)—*′, *—C(═O)—′, *—C(═S)—′, *—N(R.sub.31)—*′, *—P(R.sub.31)—*′, *—[Si(R.sub.31)(R.sub.32)]k11-*′, or *—P(R.sub.31)(R.sub.32)—′ to form a substituted or unsubstituted C.sub.5-C.sub.30 carbocyclic group or a substituted or unsubstituted C.sub.1-C.sub.30 heterocyclic group, [0324] A.sub.31 may be a C.sub.5-C.sub.30 carbocyclic group, [0325] R.sub.31 and R.sub.32 may each be the same as described in connection with R11, and [0326] k11 may be 1, 2, 3, and 4.

[0327] In an embodiment, the fluorescent host represented by Formula FH-2 may be compounds of Group FH2, but embodiments of the present disclosure are not limited thereto:

##STR01355## ##STR01356## ##STR01357## ##STR01358## ##STR01359## ##STR01360## ##STR01361## ##STR01362## ##STR01363## ##STR01364## ##STR01365## ##STR01366## ##STR01367## ##STR01368## ##STR01369## ##STR01370## ##STR01371## ##STR01372## ##STR01373## ##STR01374## ##STR01375## ##STR01376## ##STR01377## ##STR01378## ##STR01379## ##STR01380## ##STR01381## ##STR01382## ##STR01383## ##STR01384## ##STR01385## ##STR01386## ##STR01387## ##STR01388## ##STR01389## ##STR01390## ##STR01391## ##STR01392## ##STR01393## ##STR01394## ##STR01395## ##STR01396## ##STR01397## ##STR01398## ##STR01399## ##STR01400## ##STR01401## ##STR01402## ##STR01403## ##STR01404## ##STR01405## ##STR01406## ##STR01407## ##STR01408## ##STR01409##

##STR01410## ##STR01411## ##STR01412## ##STR01413## ##STR01414## ##STR01415## ##STR01416## ##STR01417## ##STR01418## ##STR01419## ##STR01420## ##STR01421## ##STR01422## ##STR01423## ##STR01424## ##STR01425## ##STR01426## ##STR01427## ##STR01428## ##STR01429## ##STR01430## ##STR01431## ##STR01432## ##STR01433## ##STR01434## ##STR01435## ##STR01436## ##STR01437## ##STR01438## ##STR01439## ##STR01440## ##STR01441## ##STR01442## ##STR01443## ##STR01444## ##STR01445## ##STR01446## ##STR01447## ##STR01448## ##STR01449## ##STR01450## ##STR01451## ##STR01452## ##STR01453## ##STR01454## ##STR01455## ##STR01456## ##STR01457## ##STR01458## ##STR01459## ##STR01460## ##STR01461## ##STR01462## ##STR01463## ##STR01464## ##STR01465## ##STR01466## ##STR01467## ##STR01468## ##STR01469## ##STR01470## ##STR01471## ##STR01472## ##STR01473## ##STR01474##

##STR01475## ##STR01476## ##STR01477## ##STR01478## ##STR01479## ##STR01480## ##STR01481## ##STR01482## ##STR01483## ##STR01484## ##STR01485## ##STR01486## ##STR01487## ##STR01488## ##STR01489## ##STR01490## ##STR01491## ##STR01492## ##STR01493## ##STR01494## ##STR01495## ##STR01496## ##STR01497## ##STR01498## ##STR01499## ##STR01500## ##STR01501## ##STR01502## ##STR01503## ##STR01504## ##STR01505## ##STR01506## ##STR01507## ##STR01508## ##STR01509## ##STR01510## ##STR01511## ##STR01512## ##STR01513## ##STR01514## ##STR01515## ##STR01516## ##STR01517## ##STR01518## ##STR01519## ##STR01520## ##STR01521## ##STR01522## ##STR01523## ##STR01524## ##STR01525## ##STR01526##

[0328] In an embodiment, the fluorescent host may be represented by Formula FH-3:

##STR01527## [0329] wherein, in Formula FH-3, [0330] Ar.sub.1 may be a group represented by Formula 2,

##STR01528## [0331] Ar.sub.1 may include at least one cyano group, [0332] A.sub.1 and A.sub.2 may each independently be a C.sub.5-C.sub.30 carbocyclic group or a C.sub.1-C.sub.30 heterocyclic group, [0333] L.sub.1 may be an unsubstituted or substituted C.sub.5-C.sub.30 carbocyclic group or an unsubstituted or substituted C.sub.1-C.sub.30 heterocyclic group, [0334] a1 may be 0, 1, 2, or 3, [0335] when a1 is 2 or greater, two or more of L.sub.11 may be identical to or different from each other, [0336] m1 may be 0, 1, 2, or 3, [0337] Ar.sub.11 may be a group represented by Formula 4, Ar.sub.12 may be a group represented by Formula 5, and Ar.sub.13 may be a group represented by Formula 6:

##STR01529##

[0338] In Formulae 4 to 6, [0339] R.sub.1, R.sub.10, R.sub.20, R.sub.30, R.sub.40, R.sub.50, and R.sub.60 may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, —SF.sub.5, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C.sub.1-C.sub.60 alkyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkenyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkynyl group, a substituted or unsubstituted C.sub.1-C.sub.60 alkoxy group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted heterocycloalkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenyl group, a substituted or unsubstituted C.sub.1-C.sub.10heterocycloalkenyl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryloxy group, a substituted or unsubstituted C.sub.6-C.sub.60 arylthio group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryl group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryloxy group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroarylthio group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —N(Q.sub.1)(Q.sub.2), —Si(Q.sub.3)(Q.sub.4)(Q.sub.5), —B(Q.sub.6)(Q.sub.7), or —P(═O)(Q.sub.8)(Q.sub.9), [0340] b1 may be an integer from 1 to 5, [0341] when b1 is 2 or greater, two or more of R.sub.1 may be identical to or different from each other, [0342] b10 may be an integer from 1 to 8, when b10 is 2 or greater, two or more of R.sub.10 may be identical to or different from each other, [0343] b20 and b30 may each independently be an integer from 1 to 4, [0344] when b20 is 2 or greater, two or more of R.sub.20 may be identical to or different from each other, and when b30 2 or greater, two or more of R.sub.30 may be identical to or different from each other, [0345] b40, b50, and b60 may each independently be an integer from 1 to 4, [0346] when b40 is 2 or greater, two or more of R.sub.40 may be identical to or different from each other, when b50 is 2 or greater, two or more of R.sub.50 may be identical to or different from each other, and when b60 is 2 or greater, two or more R.sub.60 may be identical to or different from each other, and [0347] * and *1 each indicate a binding site to a neighboring atom.

[0348] In an embodiment, the fluorescent host represented by Formula FH-3 may be a compound of Group FH3, but embodiments of the present disclosure are not limited thereto:

##STR01530## ##STR01531## ##STR01532## ##STR01533## ##STR01534## ##STR01535## ##STR01536## ##STR01537## ##STR01538## ##STR01539## ##STR01540## ##STR01541## ##STR01542## ##STR01543## ##STR01544## ##STR01545## ##STR01546## ##STR01547## ##STR01548## ##STR01549## ##STR01550## ##STR01551## ##STR01552## ##STR01553## ##STR01554## ##STR01555## ##STR01556## ##STR01557## ##STR01558## ##STR01559## ##STR01560## ##STR01561## ##STR01562## ##STR01563## ##STR01564## ##STR01565## ##STR01566## ##STR01567## ##STR01568## ##STR01569## ##STR01570## ##STR01571## ##STR01572## ##STR01573## ##STR01574## ##STR01575## ##STR01576## ##STR01577## ##STR01578## ##STR01579## ##STR01580## ##STR01581## ##STR01582## ##STR01583## ##STR01584## ##STR01585## ##STR01586## ##STR01587## ##STR01588## ##STR01589## ##STR01590## ##STR01591## ##STR01592## ##STR01593## ##STR01594## ##STR01595## ##STR01596##

##STR01597## ##STR01598## ##STR01599## ##STR01600## ##STR01601## ##STR01602## ##STR01603## ##STR01604## ##STR01605## ##STR01606## ##STR01607## ##STR01608## ##STR01609## ##STR01610## ##STR01611## ##STR01612## ##STR01613## ##STR01614## ##STR01615## ##STR01616## ##STR01617## ##STR01618##

##STR01619## ##STR01620## ##STR01621## ##STR01622## ##STR01623## ##STR01624## ##STR01625## ##STR01626## ##STR01627## ##STR01628## ##STR01629## ##STR01630## ##STR01631## ##STR01632## ##STR01633## ##STR01634## ##STR01635## ##STR01636## ##STR01637## ##STR01638## ##STR01639## ##STR01640## ##STR01641## ##STR01642## ##STR01643## ##STR01644## ##STR01645## ##STR01646## ##STR01647##

[0349] In an embodiment, the fluorescent host may be represented by Formula FH-4:

##STR01648## [0350] wherein, in Formula FH-4, [0351] X.sub.1 may be O or Se, [0352] Ar.sub.1 may be a group represented by Formula 1A, and Ar.sub.2 may be a group represented by Formula 1B:

##STR01649##

[0353] In Formulae 1A and 1B, [0354] L.sub.1 and L.sub.2 may each independently a substituted or unsubstituted C.sub.5-C.sub.30 carbocyclic group or a substituted or unsubstituted C.sub.1-C.sub.30 heterocyclic group, [0355] a1 and a2 may each independently be an integer from 0 to 3, [0356] when a1 is 2 or greater, two or more of L.sub.1 may be identical to or different from each other, and when a2 is 2 or greater, two or more of L.sub.2 may be identical to or different from each other, [0357] R.sub.1, R.sub.2, R.sub.10, R.sub.20, R.sub.30, and R.sub.40 may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, —SF.sub.5, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C.sub.1-C.sub.60 alkyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkenyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkynyl group, a substituted or unsubstituted C.sub.1-C.sub.60 alkoxy group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenyl group, a substituted or unsubstituted C.sub.2-C.sub.10 heterocycloalkenyl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryloxy group, a substituted or unsubstituted C.sub.6-C.sub.60 arylthio group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —N(Q.sub.1)(Q.sub.2), —Si(Q.sub.3)(Q.sub.4)(Q.sub.5), —B(Q.sub.6)(Q.sub.7), or —P(═O)(Q.sub.8)(Q.sub.9), [0358] b1 and b2 may each independently be an integer from 1 to 5, [0359] when b1 is 2 or greater, two or more of R.sub.1 may be identical to or different from each other, and when b2 is 2 or greater, two or more of R.sub.2 may be identical to or different from each other, [0360] b10 and b20 may each independently an integer from 1 to 8, [0361] b30 and b40 may each independently an integer from 1 to 3, [0362] c1 and c2 may each independently be an integer from 1 to 8, and [0363] the sum of b10 and c1 may be 9, and the sum of b20 and c2 may be 9.

[0364] In an embodiment, the fluorescent host represented by Formula FH-4 may be a compound of Group FH4, but embodiments of the present disclosure are not limited thereto:

##STR01650## ##STR01651## ##STR01652## ##STR01653## ##STR01654## ##STR01655## ##STR01656## ##STR01657## ##STR01658## ##STR01659## ##STR01660## ##STR01661## ##STR01662## ##STR01663## ##STR01664## ##STR01665## ##STR01666## ##STR01667## ##STR01668## ##STR01669## ##STR01670## ##STR01671## ##STR01672## ##STR01673## ##STR01674## ##STR01675## ##STR01676## ##STR01677## ##STR01678## ##STR01679## ##STR01680## ##STR01681## ##STR01682## ##STR01683## ##STR01684## ##STR01685## ##STR01686## ##STR01687## ##STR01688## ##STR01689## ##STR01690## ##STR01691## ##STR01692## ##STR01693## ##STR01694## ##STR01695## ##STR01696## ##STR01697## ##STR01698## ##STR01699## ##STR01700## ##STR01701## ##STR01702## ##STR01703## ##STR01704## ##STR01705## ##STR01706## ##STR01707## ##STR01708## ##STR01709## ##STR01710## ##STR01711## ##STR01712## ##STR01713## ##STR01714## ##STR01715## ##STR01716## ##STR01717## ##STR01718## ##STR01719## ##STR01720## ##STR01721## ##STR01722## ##STR01723## ##STR01724## ##STR01725## ##STR01726## ##STR01727## ##STR01728## ##STR01729## ##STR01730## ##STR01731## ##STR01732## ##STR01733## ##STR01734## ##STR01735## ##STR01736## ##STR01737## ##STR01738## ##STR01739## ##STR01740## ##STR01741## ##STR01742## ##STR01743## ##STR01744## ##STR01745## ##STR01746## ##STR01747## ##STR01748## ##STR01749## ##STR01750## ##STR01751## ##STR01752## ##STR01753## ##STR01754## ##STR01755## ##STR01756## ##STR01757##

##STR01758## ##STR01759## ##STR01760## ##STR01761## ##STR01762## ##STR01763## ##STR01764## ##STR01765## ##STR01766## ##STR01767## ##STR01768## ##STR01769## ##STR01770## ##STR01771## ##STR01772## ##STR01773## ##STR01774## ##STR01775## ##STR01776## ##STR01777## ##STR01778## ##STR01779## ##STR01780## ##STR01781## ##STR01782## ##STR01783## ##STR01784## ##STR01785## ##STR01786## ##STR01787## ##STR01788## ##STR01789## ##STR01790## ##STR01791## ##STR01792## ##STR01793## ##STR01794## ##STR01795##

##STR01796## ##STR01797## ##STR01798## ##STR01799## ##STR01800## ##STR01801## ##STR01802## ##STR01803## ##STR01804## ##STR01805## ##STR01806## ##STR01807## ##STR01808## ##STR01809## ##STR01810## ##STR01811## ##STR01812## ##STR01813## ##STR01814## ##STR01815## ##STR01816## ##STR01817## ##STR01818## ##STR01819##

##STR01820## ##STR01821## ##STR01822## ##STR01823## ##STR01824## ##STR01825## ##STR01826## ##STR01827## ##STR01828## ##STR01829## ##STR01830## ##STR01831## ##STR01832## ##STR01833## ##STR01834## ##STR01835## ##STR01836## ##STR01837## ##STR01838## ##STR01839## ##STR01840## ##STR01841## ##STR01842## ##STR01843## ##STR01844## ##STR01845## ##STR01846## ##STR01847## ##STR01848## ##STR01849## ##STR01850## ##STR01851## ##STR01852## ##STR01853## ##STR01854## ##STR01855## ##STR01856## ##STR01857## ##STR01858## ##STR01859## ##STR01860## ##STR01861## ##STR01862## ##STR01863## ##STR01864## ##STR01865## ##STR01866## ##STR01867## ##STR01868##

##STR01869## ##STR01870## ##STR01871## ##STR01872## ##STR01873## ##STR01874## ##STR01875## ##STR01876## ##STR01877## ##STR01878## ##STR01879## ##STR01880## ##STR01881## ##STR01882## ##STR01883## ##STR01884## ##STR01885## ##STR01886## ##STR01887## ##STR01888## ##STR01889## ##STR01890## ##STR01891## ##STR01892## ##STR01893## ##STR01894## ##STR01895## ##STR01896## ##STR01897## ##STR01898## ##STR01899## ##STR01900## ##STR01901## ##STR01902## ##STR01903## ##STR01904## ##STR01905## ##STR01906## ##STR01907## ##STR01908## ##STR01909## ##STR01910## ##STR01911## ##STR01912## ##STR01913## ##STR01914## ##STR01915## ##STR01916## ##STR01917## ##STR01918## ##STR01919## ##STR01920## ##STR01921## ##STR01922## ##STR01923## ##STR01924## ##STR01925## ##STR01926## ##STR01927## ##STR01928## ##STR01929## ##STR01930## ##STR01931## ##STR01932## ##STR01933## ##STR01934##

##STR01935## ##STR01936## ##STR01937## ##STR01938## ##STR01939## ##STR01940## ##STR01941## ##STR01942## ##STR01943## ##STR01944## ##STR01945## ##STR01946## ##STR01947## ##STR01948## ##STR01949## ##STR01950## ##STR01951## ##STR01952## ##STR01953## ##STR01954## ##STR01955## ##STR01956## ##STR01957## ##STR01958## ##STR01959## ##STR01960## ##STR01961## ##STR01962## ##STR01963## ##STR01964## ##STR01965## ##STR01966## ##STR01967## ##STR01968## ##STR01969## ##STR01970## ##STR01971## ##STR01972## ##STR01973## ##STR01974## ##STR01975## ##STR01976## ##STR01977## ##STR01978## ##STR01979## ##STR01980## ##STR01981## ##STR01982## ##STR01983## ##STR01984## ##STR01985## ##STR01986## ##STR01987## ##STR01988## ##STR01989## ##STR01990## ##STR01991## ##STR01992## ##STR01993## ##STR01994## ##STR01995## ##STR01996## ##STR01997## ##STR01998## ##STR01999## ##STR02000## ##STR02001## ##STR02002## ##STR02003## ##STR02004## ##STR02005## ##STR02006## ##STR02007## ##STR02008## ##STR02009## ##STR02010## ##STR02011## ##STR02012## ##STR02013## ##STR02014## ##STR02015## ##STR02016## ##STR02017## ##STR02018## ##STR02019## ##STR02020## ##STR02021## ##STR02022## ##STR02023## ##STR02024##

##STR02025## ##STR02026## ##STR02027## ##STR02028## ##STR02029## ##STR02030## ##STR02031## ##STR02032## ##STR02033## ##STR02034## ##STR02035## ##STR02036## ##STR02037## ##STR02038## ##STR02039## ##STR02040## ##STR02041## ##STR02042## ##STR02043## ##STR02044## ##STR02045## ##STR02046## ##STR02047## ##STR02048## ##STR02049## ##STR02050## ##STR02051## ##STR02052## ##STR02053## ##STR02054## ##STR02055## ##STR02056## ##STR02057## ##STR02058## ##STR02059## ##STR02060## ##STR02061## ##STR02062## ##STR02063## ##STR02064## ##STR02065## ##STR02066## ##STR02067## ##STR02068## ##STR02069## ##STR02070## ##STR02071## ##STR02072## ##STR02073## ##STR02074## ##STR02075## ##STR02076## ##STR02077## ##STR02078## ##STR02079## ##STR02080## ##STR02081## ##STR02082## ##STR02083## ##STR02084## ##STR02085## ##STR02086## ##STR02087## ##STR02088## ##STR02089## ##STR02090## ##STR02091## ##STR02092##

##STR02093## ##STR02094## ##STR02095## ##STR02096## ##STR02097## ##STR02098## ##STR02099## ##STR02100## ##STR02101## ##STR02102## ##STR02103## ##STR02104## ##STR02105## ##STR02106## ##STR02107## ##STR02108## ##STR02109## ##STR02110## ##STR02111## ##STR02112## ##STR02113## ##STR02114## ##STR02115## ##STR02116## ##STR02117## ##STR02118## ##STR02119## ##STR02120## ##STR02121## ##STR02122## ##STR02123## ##STR02124## ##STR02125## ##STR02126## ##STR02127## ##STR02128## ##STR02129## ##STR02130## ##STR02131## ##STR02132## ##STR02133## ##STR02134## ##STR02135## ##STR02136## ##STR02137## ##STR02138## ##STR02139## ##STR02140## ##STR02141## ##STR02142## ##STR02143## ##STR02144## ##STR02145## ##STR02146## ##STR02147## ##STR02148## ##STR02149## ##STR02150## ##STR02151## ##STR02152## ##STR02153##

##STR02154## ##STR02155## ##STR02156## ##STR02157## ##STR02158## ##STR02159## ##STR02160## ##STR02161## ##STR02162## ##STR02163## ##STR02164## ##STR02165## ##STR02166## ##STR02167## ##STR02168## ##STR02169## ##STR02170## ##STR02171## ##STR02172## ##STR02173## ##STR02174## ##STR02175## ##STR02176## ##STR02177## ##STR02178## ##STR02179## ##STR02180## ##STR02181## ##STR02182## ##STR02183## ##STR02184## ##STR02185## ##STR02186## ##STR02187## ##STR02188## ##STR02189## ##STR02190## ##STR02191## ##STR02192## ##STR02193## ##STR02194## ##STR02195## ##STR02196## ##STR02197## ##STR02198## ##STR02199## ##STR02200##

[0365] When the host is a mixture of an electron-transporting host and a hole-transporting host, the weight ratio of the electron-transporting host and the hole-transporting host may be 1:9 to 9:1, for example, 2:8 to 8:2, for example, 4:6 to 6:4, for example, 5:5. When the weight ratio of the electron-transporting host and the hole-transporting host satisfies the above-described ranges, the hole-and-electron-transporting balance in the emission layer 15 may be made.

[0366] Dopant in Emission Layer 15

[0367] The dopant may include the heterocyclic compound.

[0368] Sensitizer in Emission Layer 15

[0369] In an embodiment, the sensitizer may include a phosphorescent sensitizer including at least one metal Period 1 transition metal, Period 2 transition metal, Period 3 transition metal, or a combination thereof.

[0370] In an embodiment, the sensitizer may include metal an organic ligand (L.sub.11) including at least one metal (M.sub.11) of a first-row transition metal of the Periodic Table of Elements, a second-row transition metal of the Periodic Table of Elements, a third-row transition metal of the Periodic Table of Elements, or a combination thereof, and L.sub.11 and M.sub.11 may form 1, 2, 3, or 4 cyclometalated rings.

[0371] In an embodiment, the sensitizer may include an organometallic compound represented by Formula 101:

M.sub.11(L.sub.11).sub.n11(L.sub.12).sub.n12  Formula 101 [0372] wherein, in Formula 101, [0373] M.sub.11 may be a first-row transition metal of the Periodic Table of Elements, a second-row transition metal of the Periodic Table of Elements, a third-row transition metal of the Periodic Table of Elements, or a combination thereof; [0374] may be a ligand represented by one of Formulae 1-1 to 1-4; [0375] L.sub.12 may be a monodentate ligand or a bidentate ligand; [0376] n11 may be 1, [0377] n12 may be 0, 1, or 2:

##STR02201## [0378] wherein, in Formulae 1-1 to 1-4, [0379] A.sub.1 to A.sub.4 may each independently be a substituted or unsubstituted C.sub.5-C.sub.30 carbocyclic group, a substituted or unsubstituted C.sub.1-C.sub.30 heterocyclic group, or a non-cyclic group, [0380] Y.sub.11 to Y.sub.14 may each independently be a chemical bond, O, S, N(R.sub.91), B(R.sub.91), P(R.sub.91), or C(R.sub.91)(R.sub.92), [0381] T.sub.1 to T.sub.4 may each independently be a single bond, a double bond, *—N(R.sub.93)—*′, *—B(R.sub.93)—′, *-1D(R.sub.93)—′, *—C(R.sub.93)(R.sub.94)—′, *—Si(R.sub.93)(R.sub.94)—*′, *—Ge(R.sub.93)(R.sub.94)—′, *—S-′, *—Se-′, *—O-′, *—C(═O)—′, *—S(═O)—′, *—S(═O).sub.2-′, *—C(R.sub.93)=′, *═C(R.sub.93)—*′, *—C(R.sub.93)═C(R.sub.94)—*′, *—C(═S)—′, or *—C≡C-′, [0382] a substituent of the substituted C.sub.5-C.sub.30 carbocyclic group, a substituent of substituted C.sub.1-C.sub.30 heterocyclic group, and R.sub.91 to R.sub.94 may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, —SF.sub.5, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid or a salt thereof, a sulfonic acid or a salt thereof, a phosphoric acid or a salt thereof, a substituted or unsubstituted C.sub.1-C.sub.60 alkyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkenyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkynyl group, a substituted or unsubstituted C.sub.1-C.sub.60 alkoxy group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenyl group, a substituted or unsubstituted C.sub.2-C.sub.10 heterocycloalkenyl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryloxy group, a substituted or unsubstituted C.sub.6-C.sub.60 arylthio group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryl group, a substituted or unsubstituted monovalent aromatic condensed polycyclic group, a substituted or unsubstituted monovalent aromatic condensed heteropolycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q.sub.1)(Q.sub.2)(Q.sub.3), —Ge(Q.sub.1)(Q.sub.2)(Q.sub.3), —B(Q.sub.1)(Q.sub.2), —N(Q.sub.1)(Q.sub.2), —P(Q.sub.1)(Q.sub.2), —C(═O)(Q.sub.1), —S(═O)(Q.sub.1), —S(═O).sub.2(Q.sub.1), —P(═O)(Q.sub.1)(Q.sub.2), or —P(═S)(Q.sub.1)(Q.sub.2), wherein each of a substituent of the substituted C.sub.5-C.sub.30 carbocyclic group and a substituent of substituted C.sub.1-C.sub.30 heterocyclic group is not hydrogen, [0383] *.sub.1, *.sub.2, *.sub.3, and *.sub.4 each indicate a binding site to M.sub.11 and [0384] Q.sub.1 to Q.sub.3 may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, a C.sub.1-C.sub.60 alkoxy group, a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.2-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.7-C.sub.60 alkylaryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a C.sub.2-C.sub.60 heteroalkylaryl group, a C.sub.1-C.sub.60 heteroaryloxy group, a C.sub.1-C.sub.60 heteroarylthio group, a monovalent aromatic condensed polycyclic group, a monovalent aromatic condensed heteropolycyclic group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a C.sub.1-C.sub.60 alkyl group that is substituted with at least one deuterium, —F, a cyano group, a C.sub.1-C.sub.60 alkyl group, a C.sub.6-C.sub.60 aryl group, or a combination thereof, or a C.sub.6-C.sub.60 aryl group that is substituted with deuterium, —F, a cyano group, a C.sub.1-C.sub.60 alkyl group, a C.sub.6-C.sub.60 aryl group, or a combination thereof.

[0385] In one or more embodiments, the sensitizer may be compounds of Groups I to VIII, but embodiments of the present disclosure are not limited thereto:

##STR02202## ##STR02203## ##STR02204## ##STR02205## ##STR02206## ##STR02207## ##STR02208## ##STR02209## ##STR02210## ##STR02211## ##STR02212## ##STR02213## ##STR02214## ##STR02215## ##STR02216## ##STR02217## ##STR02218## ##STR02219## ##STR02220## ##STR02221## ##STR02222## ##STR02223## ##STR02224## ##STR02225## ##STR02226## ##STR02227## ##STR02228## ##STR02229## ##STR02230## ##STR02231## ##STR02232## ##STR02233## ##STR02234## ##STR02235## ##STR02236## ##STR02237## ##STR02238## ##STR02239## ##STR02240## ##STR02241## ##STR02242## ##STR02243## ##STR02244## ##STR02245## ##STR02246##

##STR02247## ##STR02248## ##STR02249## ##STR02250## ##STR02251## ##STR02252## ##STR02253## ##STR02254## ##STR02255## ##STR02256## ##STR02257## ##STR02258## ##STR02259## ##STR02260## ##STR02261## ##STR02262## ##STR02263## ##STR02264## ##STR02265## ##STR02266## ##STR02267## ##STR02268## ##STR02269## ##STR02270## ##STR02271## ##STR02272## ##STR02273## ##STR02274## ##STR02275## ##STR02276## ##STR02277## ##STR02278## ##STR02279## ##STR02280## ##STR02281## ##STR02282## ##STR02283## ##STR02284## ##STR02285## ##STR02286## ##STR02287## ##STR02288## ##STR02289## ##STR02290## ##STR02291## ##STR02292## ##STR02293## ##STR02294## ##STR02295## ##STR02296## ##STR02297## ##STR02298## ##STR02299## ##STR02300## ##STR02301## ##STR02302## ##STR02303## ##STR02304## ##STR02305## ##STR02306## ##STR02307##

##STR02308## ##STR02309## ##STR02310## ##STR02311## ##STR02312## ##STR02313## ##STR02314## ##STR02315## ##STR02316## ##STR02317## ##STR02318## ##STR02319## ##STR02320## ##STR02321## ##STR02322## ##STR02323## ##STR02324## ##STR02325## ##STR02326## ##STR02327## ##STR02328## ##STR02329## ##STR02330## ##STR02331## ##STR02332## ##STR02333## ##STR02334## ##STR02335## ##STR02336## ##STR02337## ##STR02338## ##STR02339## ##STR02340## ##STR02341## ##STR02342## ##STR02343## ##STR02344## ##STR02345## ##STR02346## ##STR02347## ##STR02348## ##STR02349## ##STR02350## ##STR02351## ##STR02352## ##STR02353## ##STR02354## ##STR02355## ##STR02356## ##STR02357## ##STR02358## ##STR02359## ##STR02360## ##STR02361## ##STR02362## ##STR02363## ##STR02364## ##STR02365## ##STR02366## ##STR02367## ##STR02368## ##STR02369## ##STR02370## ##STR02371## ##STR02372## ##STR02373## ##STR02374## ##STR02375## ##STR02376## ##STR02377## ##STR02378## ##STR02379## ##STR02380## ##STR02381## ##STR02382## ##STR02383## ##STR02384## ##STR02385## ##STR02386## ##STR02387## ##STR02388## ##STR02389## ##STR02390## ##STR02391## ##STR02392## ##STR02393## ##STR02394## ##STR02395## ##STR02396## ##STR02397## ##STR02398##

##STR02399## ##STR02400## ##STR02401## ##STR02402## ##STR02403## ##STR02404## ##STR02405## ##STR02406## ##STR02407## ##STR02408## [0386] a compound represented by Formula A:

(L.sub.101).sub.n101-M.sub.101-(L.sub.102).sub.m101  Formula A [0387] wherein L.sub.101, n.sub.101, M.sub.101, L.sub.102, and m101 in Formula A may each be the same as described in Tables 1 to 3:

TABLE-US-00001 TABLE 1 Compound name L101 n101 M101 L102 m101 BD001 LM1 3 Ir — 0 BD002 LM2 3 Ir — 0 BD003 LM3 3 Ir — 0 BD004 LM4 3 Ir — 0 BD005 LM5 3 Ir — 0 BD006 LM6 3 Ir — 0 BD007 LM7 3 Ir — 0 BD008 LM8 3 Ir — 0 BD009 LM9 3 Ir — 0 BD010 LM10 3 Ir — 0 BD011 LM11 3 Ir — 0 BD012 LM12 3 Ir — 0 BD013 LM13 3 Ir — 0 BD014 LM14 3 Ir — 0 BD015 LM15 3 Ir — 0 BD016 LM16 3 Ir — 0 BD017 LM17 3 Ir — 0 BD018 LM18 3 Ir — 0 BD019 LM19 3 Ir — 0 BD020 LM20 3 Ir — 0 BD021 LM21 3 Ir — 0 BD022 LM22 3 Ir — 0 BD023 LM23 3 Ir — 0 BD024 LM24 3 Ir — 0 BD025 LM25 3 Ir — 0 BD026 LM26 3 Ir — 0 BD027 LM27 3 Ir — 0 BD028 LM28 3 Ir — 0 BD029 LM29 3 Ir — 0 BD030 LM30 3 Ir — 0 BD031 LM31 3 Ir — 0 BD032 LM32 3 Ir — 0 BD033 LM33 3 Ir — 0 BD034 LM34 3 Ir — 0 BD035 LM35 3 Ir — 0 BD036 LM36 3 Ir — 0 BD037 LM37 3 Ir — 0 BD038 LM38 3 Ir — 0 BD039 LM39 3 In — 0 BD040 LM40 3 Ir — 0 BD041 LM41 3 Ir — 0 BD042 LM42 3 Ir — 0 BD043 LM43 3 Ir — 0 BD044 LM44 3 Ir — 0 BD045 LM45 3 Ir — 0 BD046 LM46 3 Ir — 0 BD047 LM47 3 Ir — 0 BD048 LM48 3 Ir — 0 BD049 LM49 3 Ir — 0 BD050 LM50 3 Ir — 0 BD051 LM51 3 Ir — 0 BD052 LM52 3 Ir — 0 BD053 LM53 3 Ir — 0 BD054 LM54 3 Ir — 0 BD055 LM55 3 Ir — 0 BD056 LM56 3 Ir — 0 BD057 LM57 3 Ir — 0 BD058 LM58 3 Ir — 0 BD059 LM59 3 Ir — 0 BD060 LM60 3 Ir — 0 BD061 LM61 3 Ir — 0 BD062 LM62 3 Ir — 0 BD063 LM63 3 Ir — 0 BD064 LM64 3 Ir — 0 BD065 LM65 3 Ir — 0 BD066 LM66 3 Ir — 0 BD067 LM67 3 Ir — 0 BD068 LM68 3 Ir — 0 BD069 LM69 3 Ir — 0 BD070 LM70 3 Ir — 0 BD071 LM71 3 Ir — 0 BD072 LM72 3 Ir — 0 BD073 LM73 3 Ir — 0 BD074 LM74 3 Ir — 0 BD075 LM75 3 Ir — 0 BD076 LM76 3 Ir — 0 BD077 LM77 3 Ir — 0 BD078 LM78 3 Ir — 0 BD079 LM79 3 Ir — 0 BD080 LM80 3 Ir — 0 BD081 LM81 3 Ir — 0 BD082 LM82 3 Ir — 0 BD083 LM83 3 Ir — 0 BD084 LM84 3 Ir — 0 BD085 LM85 3 Ir — 0 BD086 LM86 3 Ir — 0 BD087 LM87 3 Ir — 0 BD088 LM88 3 Ir — 0 BD089 LM89 3 Ir — 0 BD090 LM90 3 Ir — 0 BD091 LM91 3 Ir — 0 BD092 LM92 3 Ir — 0 BD093 LM93 3 Ir — 0 BD094 LM94 3 Ir — 0 BD095 LM95 3 Ir — 0 BD096 LM96 3 Ir — 0 BD097 LM97 3 Ir — 0 BD098 LM98 3 Ir — 0 BD099 LM99 3 Ir — 0 BD100 LM100 3 Ir — 0

TABLE-US-00002 TABLE 2 Compound name L101 n101 M101 L102 m101 BD101 LM101 3 Ir — 0 BD102 LM102 3 Ir — 0 BD103 LM103 3 Ir — 0 BD104 LM104 3 Ir — 0 BD105 LM105 3 Ir — 0 BD106 LM106 3 Ir — 0 BD107 LM107 3 Ir — 0 BD108 LM108 3 Ir — 0 BD109 LM109 3 Ir — 0 BD110 LM110 3 Ir — 0 BD111 LM111 3 Ir — 0 BD112 LM112 3 Ir — 0 BD113 LM113 3 Ir — 0 BD114 LM114 3 Ir — 0 BD115 LM115 3 Ir — 0 BD116 LM116 3 Ir — 0 BD117 LM117 3 Ir — 0 BD118 LM118 3 Ir — 0 BD119 LM119 3 Ir — 0 BD120 LM120 3 Ir — 0 BD121 LM121 3 Ir — 0 BD122 LM122 3 Ir — 0 BD123 LM123 3 Ir — 0 BD124 LM124 3 Ir — 0 BD125 LM125 3 Ir — 0 BD126 LM126 3 Ir — 0 BD127 LM127 3 Ir — 0 BD128 LM128 3 Ir — 0 BD129 LM129 3 Ir — 0 BD130 LM130 3 Ir — 0 BD131 LM131 3 Ir — 0 BD132 LM132 3 Ir — 0 BD133 LM133 3 Ir — 0 BD134 LM134 3 Ir — 0 BD135 LM135 3 Ir — 0 BD136 LM136 3 Ir — 0 BD137 LM137 3 Ir — 0 BD138 LM138 3 Ir — 0 BD139 LM139 3 Ir — 0 BD140 LM140 3 Ir — 0 BD141 LM141 3 Ir — 0 BD142 LM142 3 Ir — 0 BD143 LM143 3 Ir — 0 BD144 LM144 3 Ir — 0 BD145 LM145 3 Ir — 0 BD146 LM146 3 Ir — 0 BD147 LM147 3 Ir — 0 BD148 LM148 3 Ir — 0 BD149 LM149 3 Ir — 0 BD150 LM150 3 Ir — 0 BD151 LM151 3 Ir — 0 BD152 LM152 3 Ir — 0 BD153 LM153 3 In — 0 BD154 LM154 3 Ir — 0 BD155 LM155 3 Ir — 0 BD156 LM156 3 Ir — 0 BD157 LM157 3 Ir — 0 BD158 LM158 3 Ir — 0 BD159 LM159 3 Ir — 0 BD160 LM160 3 Ir — 0 BD161 LM161 3 Ir — 0 BD162 LM162 3 Ir — 0 BD163 LM163 3 Ir — 0 BD164 LM164 3 Ir — 0 BD165 LM165 3 Ir — 0 BD166 LM166 3 Ir — 0 BD167 LM167 3 Ir — 0 BD168 LM168 3 Ir — 0 BD169 LM169 3 Ir — 0 BD170 LM170 3 Ir — 0 BD171 LM171 3 Ir — 0 BD172 LM172 3 Ir — 0 BD173 LM173 3 Ir — 0 BD174 LM174 3 Ir — 0 BD175 LM175 3 Ir — 0 BD176 LM176 3 Ir — 0 BD177 LM177 3 Ir — 0 BD178 LM178 3 Ir — 0 BD179 LM179 3 Ir — 0 BD180 LM180 3 Ir — 0 BD181 LM181 3 Ir — 0 BD182 LM182 3 Ir — 0 BD183 LM183 3 Ir — 0 BD184 LM184 3 Ir — 0 BD185 LM185 3 Ir — 0 BD186 LM186 3 Ir — 0 BD187 LM187 3 Ir — 0 BD188 LM188 3 Ir — 0 BD189 LM189 3 Ir — 0 BD190 LM190 3 Ir — 0 BD191 LM191 3 Ir — 0 BD192 LM192 3 Ir — 0 BD193 LM193 3 Ir — 0 BD194 LM194 3 Ir — 0 BD195 LM195 3 Ir — 0 BD196 LM196 3 Ir — 0 BD197 LM197 3 Ir — 0 BD198 LM198 3 Ir — 0 BD199 LM199 3 Ir — 0 BD200 LM200 3 Ir — 0

TABLE-US-00003 TABLE 3 Compound name L101 n101 M101 L102 m101 BD201 LM201 3 Ir — 0 BD202 LM202 3 Ir — 0 BD203 LM203 3 Ir — 0 BD204 LM204 3 Ir — 0 BD205 LM205 3 Ir — 0 BD206 LM206 3 Ir — 0 BD207 LM207 3 Ir — 0 BD208 LM208 3 Ir — 0 BD209 LM209 3 Ir — 0 BD210 LM210 3 Ir — 0 BD211 LM211 3 Ir — 0 BD212 LM212 3 Ir — 0 BD213 LM213 3 Ir — 0 BD214 LM214 3 Ir — 0 BD215 LM215 3 Ir — 0 BD216 LM216 3 Ir — 0 BD217 LM217 3 Ir — 0 BD218 LM218 3 Ir — 0 BD219 LM219 3 Ir — 0 BD220 LM220 3 Ir — 0 BD221 LM221 3 Ir — 0 BD222 LM222 3 Ir — 0 BD223 LM223 3 Ir — 0 BD224 LM224 3 Ir — 0 BD225 LM225 3 Ir — 0 BD226 LM226 3 Ir — 0 BD227 LM227 3 Ir — 0 BD228 LM228 3 Ir — 0 BD229 LM229 3 Ir — 0 BD230 LM230 3 Ir — 0 BD231 LM231 3 Ir — 0 BD232 LM232 3 Ir — 0 BD233 LM233 3 Ir — 0 BD234 LM234 3 Ir — 0 BD235 LM235 3 Ir — 0 BD236 LM236 3 Ir — 0 BD237 LM237 3 Ir — 0 BD238 LM238 3 Ir — 0 BD239 LM239 3 Ir — 0 BD240 LM240 3 Ir — 0 BD241 LM241 3 Ir — 0 BD242 LM242 3 Ir — 0 BD243 LM243 3 Ir — 0 BD244 LFM1 3 Ir — 0 BD245 LFM2 3 Ir — 0 BD246 LFM3 3 Ir — 0 BD247 LFM4 3 Ir — 0 BD248 LFM5 3 Ir — 0 BD249 LFM6 3 Ir — 0 BD250 LFM7 3 Ir — 0 BD251 LFP1 3 Ir — 0 BD252 LFP2 3 Ir — 0 BD253 LFP3 3 Ir — 0 BD254 LFP4 3 Ir — 0 BD255 LFP5 3 Ir — 0 BD256 LFP6 3 Ir — 0 BD257 LFP7 3 Ir — 0 BD258 LM47 2 Ir AN1 1 BD259 LM47 2 Ir AN2 1 BD260 LM47 2 Ir AN3 1 BD261 LM47 2 Ir AN4 1 BD262 LM47 2 Ir AN5 1 BD263 LM11 2 Pt — 0 BD264 LM13 2 Pt — 0 BD265 LM15 2 Pt — 0 BD266 LM45 2 Pt — 0 BD267 LM47 2 Pt — 0 BD268 LM49 2 Pt — 0 BD269 LM98 2 Pt — 0 BD270 LM100 2 Pt — 0 BD271 LM102 2 Pt — 0 BD272 LM132 2 Pt — 0 BD273 LM134 2 Pt — 0 BD274 LM136 2 Pt — 0 BD275 LM151 2 Pt — 0 BD276 LM153 2 Pt — 0 BD277 LM158 2 Pt — 0 BD278 LM180 2 Pt — 0 BD279 LM182 2 Pt — 0 BD280 LM187 2 Pt — 0 BD281 LM201 2 Pt — 0 BD282 LM206 2 Pt — 0 BD283 LM211 2 Pt — 0 BD284 LM233 2 Pt — 0 BD285 LM235 2 Pt — 0 BD286 LM240 2 Pt — 0 BD287 LFM5 2 Pt — 0 BD288 LFM6 2 Pt — 0 BD289 LFM7 2 Pt — 0 BD290 LFP5 2 Pt — 0 BD291 LFP6 2 Pt — 0 BD292 LFP7 2 Pt — 0 BD293 LM47 1 Pt AN1 1 BD294 LM47 1 Pt AN2 1 BD295 LM47 1 Pt AN3 1 BD296 LM47 1 Pt AN4 1 BD297 LM47 1 Pt AN5 1 [0388] LM.sub.1 to LM.sub.243 in Tables 1 to 3 may each be understood by referring to Formulae 1-1 to 1-3 and Tables 4 to 6:

##STR02409##

TABLE-US-00004 TABLE 4 Formula 1-1 Ligand name R11 R12 R13 R14 R15 R16 R17 R18 R19 R20 LM1 X1 H X3 H X1 H H H H D LM2 X1 H X3 H X1 H H H D H LM3 X1 H X3 H X1 H H H D D LM4 Y1 H X3 H Y1 H H H D D LM5 Y2 H X3 H Y2 H H H D D LM6 Y3 H X3 H Y3 H H H D D LM7 Y3 D X3 D Y3 H H H D D LM8 Y3 D X3 D Y3 D H H D D LM9 Y3 D X3 D Y3 D D H D D LM10 Y3 D X3 D Y3 D D D D D LM11 Y3 D Y11 D Y3 D D D D D LM12 Y3 D Y11 D Y3 H X1 H D D LM13 Y3 D Y11 D Y3 D Y3 D D D LM14 Y3 D Y11 D Y3 H X4 H D D LM15 Y3 D Y11 D Y3 D Y12 D D D LM16 X2 H X3 H X2 H H H H D LM17 X2 H X3 H X2 H H H D H LM18 X2 H X3 H X2 H H H D D LM19 Y4 H X3 H Y4 H H H D D LM20 Y5 H X3 H Y5 H H H D D LM21 Y6 H X3 H Y6 H H H D D LM22 Y7 H X3 H Y7 H H H D D LM23 Y8 H X3 H Y8 H H H D D LM24 Y9 H X3 H Y9 H H H D D LM25 Y10 H X3 H Y10 H H H D D LM26 Y10 D X3 D Y10 H H H D D LM27 Y10 D X3 D Y10 D H H D D LM28 Y10 D X3 D Y10 D D H D D LM29 Y10 D X3 D Y10 D D D D D LM30 Y10 D Y11 D Y10 D D D D D LM31 Y10 D Y11 D Y10 H X1 H D D LM32 Y10 D Y11 D Y10 D Y3 D D D LM33 Y10 D Y11 D Y10 H X4 H D D LM34 Y10 D Y11 D Y10 D Y12 D D D LM35 X H X4 H X1 H H H H D LM36 X1 H X4 H X1 H H H D H LM37 X1 H X4 H X1 H H H D D LM38 Y1 H X4 H Y1 H H H D D LM39 Y2 H X4 H Y2 H H H D D LM40 Y3 H X4 H Y3 H H H D D LM41 Y3 D X4 D Y3 H H H D D LM42 Y3 D X4 D Y3 D H H D D LM43 Y3 D X4 D Y3 D D H D D LM44 Y3 D X4 D Y3 D D D D D LM45 Y3 D Y12 D Y3 D D D D D LM46 Y3 D Y12 D Y3 H X1 H D D LM47 Y3 D Y12 D Y3 D Y3 D D D LM48 Y3 D Y12 D Y3 H X4 H D D LM49 Y3 D Y12 D Y3 D Y12 D D D LM50 X2 H X4 H X2 H H H H D LM51 X2 H X4 H X2 H H H D H LM52 X2 H X4 H X2 H H H D D LM53 Y4 H X4 H Y4 H H H D D LM54 Y5 H X4 H Y5 H H H D D LM55 Y6 H X4 H Y6 H H H D D LM56 Y7 H X4 H Y7 H H H D D LM57 Y8 H X4 H Y8 H H H D D LM58 Y9 H X4 H Y9 H H H D D LM59 Y10 H X4 H Y10 H H H D D LM60 Y10 D X4 D Y10 H H H D D LM61 Y10 D X4 D Y10 D H H D D LM62 Y10 D X4 D Y10 D D H D D LM63 Y10 D X4 D Y10 D D D D D LM64 Y10 D Y12 D Y10 D D D D D LM65 Y10 D Y12 D Y10 H X1 H D D LM66 Y10 D Y12 D Y10 D Y3 D D D LM67 Y10 D Y12 D Y10 H X4 H D D LM68 Y10 D Y12 D Y10 D Y12 D D D LM69 X1 H X5 H X1 H H H H D LM70 X1 H X5 H X1 H H H D H LM71 X1 H X5 H X1 H H H D D LM72 Y1 H X5 H Y1 H H H D D LM73 Y2 H X5 H Y2 H H H D D LM74 Y3 H X5 H Y3 H H H D D LM75 Y3 D X5 D Y3 H H H D D LM76 Y3 D X5 D Y3 D H H D D LM77 Y3 D X5 D Y3 D D H D D LM78 Y3 D X5 D Y3 D D D D D LM79 Y3 D Y13 D Y3 D D D D D LM80 Y3 D Y13 D Y3 H X1 H D D LM81 Y3 D Y13 D Y3 D Y3 D D D LM82 Y3 D Y13 D Y3 H X4 H D D LM83 Y3 D Y13 D Y3 D Y12 D D D LM84 X2 H X5 H X2 H H H H D LM85 X2 H X5 H X2 H H H D H LM86 X2 H X5 H X2 H H H D D LM87 Y4 H X5 H Y4 H H H D D LM88 Y5 H X5 H Y5 H H H D D LM89 Y6 H X5 H Y6 H H H D D LM90 Y7 H X5 H Y7 H H H D D LM91 Y8 H X5 H Y8 H H H D D LM92 Y9 H X5 H Y9 H H H D D LM93 Y10 H X5 H Y10 H H H D D LM94 Y10 D X5 D Y10 H H H D D LM95 Y10 D X5 D Y10 D H H D D LM96 Y10 D X5 D Y10 D D H D D LM97 Y10 D X5 D Y10 D D D D D LM98 Y10 D Y13 D Y10 D D D D D LM99 Y10 D Y13 D Y10 H X1 H D D LM100 Y10 D Y13 D Y10 D Y3 D D D LM101 Y10 D Y13 D Y10 H X4 H D D LM102 Y10 D Y13 D Y10 D Y12 D D D LM103 X1 H X6 H X1 H H H H D LM104 X1 H X6 H X1 H H H D H LM105 X1 H X6 H X1 H H H D D LM106 Y1 H X6 H Y1 H H H D D LM107 Y2 H X6 H Y2 H H H D D LM108 Y3 H X6 H Y3 H H H D D LM109 Y3 D X6 D Y3 H H H D D LM110 Y3 D X6 D Y3 D H H D D LM111 Y3 D X6 D Y3 D D H D D LM112 Y3 D X6 D Y3 D D D D D LM113 Y3 D Y14 D Y3 D D D D D LM114 Y3 D Y14 D Y3 H X1 H D D LM115 Y3 D Y14 D Y3 D Y3 D D D LM116 Y3 D Y14 D Y3 H X4 H D D LM117 Y3 D Y14 D Y3 D Y12 D D D LM118 X2 H X6 H X2 H H H H D LM119 X2 H X6 H X2 H H H D H LM120 X2 H X6 H X2 H H H D D LM121 Y4 H X6 H Y4 H H H D D LM122 Y5 H X6 H Y5 H H H D D LM123 Y6 H X6 H Y6 H H H D D LM124 Y7 H X6 H Y7 H H H D D LM125 Y8 H X6 H Y8 H H H D D LM126 Y9 H X6 H Y9 H H H D D LM127 Y10 H X6 H Y10 H H H D D LM128 Y10 D X6 D Y10 H H H D D LM129 Y10 D X6 D Y10 D H H D D LM130 Y10 D X6 D Y10 D D H D D LM131 Y10 D X6 D Y10 D D D D D LM132 Y10 D Y14 D Y10 D D D D D LM133 Y10 D Y14 D Y10 H X1 H D D LM134 Y10 D Y14 D Y10 D Y3 D D D LM135 Y10 D Y14 D Y10 H X4 H D D LM136 Y10 D Y14 D Y10 D Y12 D D D LM137 X1 H X7 H X1 H H H H D LM138 X1 H X7 H X1 H H H D H LM139 X1 H X7 H X1 H H H D D LM140 Y1 H X7 H Y1 H H H D D LM141 Y2 H X7 H Y2 H H H D D LM142 Y3 H X7 H Y3 H H H D D LM143 Y3 D X7 D Y3 H H H D D LM144 Y3 D X7 D Y3 D H H D D LM145 Y3 D X7 D Y3 D D H D D LM146 Y3 D X7 D Y3 D D D D D LM147 Y3 D X8 D Y3 D D D D D LM148 Y3 D Y16 D Y3 D D D D D LM149 Y3 D Y17 D Y3 D D D D D LM150 Y3 D Y18 D Y3 D D D D D LM151 Y3 D Y15 D Y3 D D D D D LM152 Y3 D Y15 D Y3 H X1 H D D LM153 Y3 D Y15 D Y3 D Y3 D D D LM154 Y3 D Y16 D Y3 D Y3 D D D LM155 Y3 D Y17 D Y3 D Y3 D D D LM156 Y3 D Y18 D Y3 D Y3 D D D LM157 Y3 D Y15 D Y3 H X4 H D D LM158 Y3 D Y15 D Y3 D Y12 D D D LM159 Y3 D Y16 D Y3 D Y12 D D D LM160 Y3 D Y17 D Y3 D Y12 D D D LM161 Y3 D Y18 D Y3 D Y12 D D D LM162 X2 H X7 H X2 H H H H D LM163 X2 H X7 H X2 H H H D H LM164 X2 H X7 H X2 H H H D D LM165 Y4 H X7 H Y4 H H H D D LM166 Y5 H X7 H Y5 H H H D D LM167 Y6 H X7 H Y6 H H H D D LM168 Y7 H X7 H Y7 H H H D D LM169 Y8 H X7 H Y8 H H H D D LM170 Y9 H X7 H Y9 H H H D D LM171 Y10 H X7 H Y10 H H H D D LM172 Y10 D X7 D Y10 H H H D D LM173 Y10 D X7 D Y10 D H H D D LM174 Y10 D X7 D Y10 D D H D D LM175 Y10 D X7 D Y10 D D D D D LM176 Y10 D X8 D Y10 D D D D D LM177 Y10 D Y16 D Y10 D D D D D LM178 Y10 D Y17 D Y10 D D D D D LM179 Y10 D Y18 D Y10 D D D D D LM180 Y10 D Y15 D Y10 D D D D D LM181 Y10 D Y15 D Y10 H X1 H D D LM182 Y10 D Y15 D Y10 D Y3 D D D LM183 Y10 D Y16 D Y10 D Y3 D D D LM184 Y10 D Y17 D Y10 D Y3 D D D LM185 Y10 D Y18 D Y10 D Y3 D D D LM186 Y10 D Y15 D Y10 H X4 H D D LM187 Y10 D Y15 D Y10 D Y12 D D D LM188 Y10 D Y16 D Y10 D Y12 D D D LM189 Y10 D Y17 D Y10 D Y12 D D D LM190 Y10 D Y18 D Y10 D Y12 D D D LM191 X1 X7 H H X1 H H H H D LM192 X X7 H H X1 H H H D H LM193 X1 X7 H H X1 H H H D D LM194 Y1 X7 H H Y1 H H H D D LM195 Y2 X7 H H Y2 H H H D D LM196 Y3 X7 H H Y3 H H H D D LM197 Y3 X7 D D Y3 H H H D D LM198 Y3 X7 D D Y3 D H H D D LM199 Y3 X7 D D Y3 D D H D D LM200 Y3 X7 D D Y3 D D D D D LM201 Y3 Y15 D D Y3 D D D D D LM202 Y3 Y16 D D Y3 D D D D D LM203 Y3 Y17 D D Y3 D D D D D LM204 Y3 Y18 D D Y3 D D D D D LM205 Y3 Y15 D D Y3 H X1 H D D LM206 Y3 Y15 D D Y3 D Y3 D D D LM207 Y3 Y16 D D Y3 D Y3 D D D LM208 Y3 Y17 D D Y3 D Y3 D D D LM209 Y3 Y18 D D Y3 D Y3 D D D LM210 Y3 Y15 D D Y3 H X4 H D D LM211 Y3 Y15 D D Y3 D Y12 D D D LM212 Y3 Y16 D D Y3 D Y12 D D D LM213 Y3 Y17 D D Y3 D Y12 D D D LM214 Y3 Y18 D D Y3 D Y12 D D D LM215 X2 X7 H H X2 H H H H D LM216 X2 X7 H H X2 H H H D H LM217 X2 X7 H H X2 H H H D D LM218 Y4 X7 H H Y4 H H H D D LM219 Y5 X7 H H Y5 H H H D D LM220 Y6 X7 H H Y6 H H H D D LM221 Y7 X7 H H Y7 H H H D D LM222 Y8 X7 H H Y8 H H H D D LM223 Y9 X7 H H Y9 H H H D D LM224 Y10 X7 H H Y10 H H H D D LM225 Y10 X7 D D Y10 H H H D D LM226 Y10 X7 D D Y10 D H H D D LM227 Y10 X7 D D Y10 D D H D D LM228 Y10 X7 D D Y10 D D D D D LM229 Y10 X8 D D Y10 D D D D D LM230 Y10 Y16 D D Y10 D D D D D LM231 Y10 Y17 D D Y10 D D D D D LM232 Y10 Y18 D D Y10 D D D D D LM233 Y10 Y15 D D Y10 D D D D D LM234 Y10 Y15 D D Y10 H X1 H D D LM235 Y10 Y15 D D Y10 D Y3 D D D LM236 Y10 Y16 D D Y10 D Y3 D D D LM237 Y10 Y17 D D Y10 D Y3 D D D LM238 Y10 Y18 D D Y10 D Y3 D D D LM239 Y10 Y15 D D Y10 H X4 H D D LM240 Y10 Y15 D D Y10 D Y12 D D D LM241 Y10 Y16 D D Y10 D Y12 D D D LM242 Y10 Y17 D D Y10 D Y12 D D D LM243 Y10 Y18 D D Y10 D Y12 D D D

TABLE-US-00005 TABLE 5 Formula 1-2 Ligand name R11 X11 R101 R102 R103 R104 R14 R15 R16 R17 R18 R19 R20 LFM1 Y10 N-Ph D D D D D Y10 D D D D D LFM2 Y10 S D D D D D Y10 D D D D D LFM3 Y10 O D D D D D Y10 D D D D D LFM4 Y3 O D D D D D Y3 D D D D D LFM5 Y10 O D D D D D Y10 D D D D D LFM6 Y10 O D D D D D Y10 D Y3 D D D LFM7 Y10 C D D D D D Y10 D Y12 D D D

TABLE-US-00006 TABLE 6 Formula 1-3 Ligand name R11 X11 R101 R102 R103 R104 R14 R15 R16 R17 R18 R19 R20 LFP1 Y10 N-Ph D D D D D Y10 D D D D D LFP2 Y10 S D D D D D Y10 D D D D D LFP3 Y10 O D D D D D Y10 D D D D D LFP4 Y3 O D D D D D Y3 D D D D D LFP5 Y10 O D D D D D Y10 D D D D D LFP6 Y10 O D D D D D Y10 D Y3 D D D LFP7 Y10 O D D D D D Y10 D Y12 D D D [0389] X.sub.1 to X.sub.10 and Y.sub.1 to Y.sub.18 in Tables 4 to 6 may each be the same as described below, and Ph in the tables refers to a phenyl group:

##STR02410## ##STR02411## ##STR02412## ##STR02413## ##STR02414## ##STR02415## ##STR02416## ##STR02417## ##STR02418## ##STR02419## ##STR02420## ##STR02421## ##STR02422## ##STR02423## ##STR02424## ##STR02425## ##STR02426## ##STR02427## ##STR02428## ##STR02429## ##STR02430## ##STR02431## ##STR02432## ##STR02433## ##STR02434## ##STR02435## ##STR02436## ##STR02437## ##STR02438## ##STR02439## ##STR02440## ##STR02441## ##STR02442## ##STR02443## ##STR02444## ##STR02445## ##STR02446## ##STR02447## ##STR02448## ##STR02449## ##STR02450## ##STR02451## ##STR02452## ##STR02453## ##STR02454## ##STR02455## ##STR02456## ##STR02457## ##STR02458## ##STR02459## ##STR02460## ##STR02461## ##STR02462## ##STR02463## ##STR02464## ##STR02465## ##STR02466## ##STR02467## ##STR02468## ##STR02469## ##STR02470## ##STR02471## ##STR02472## ##STR02473## ##STR02474## ##STR02475## ##STR02476## ##STR02477## ##STR02478## ##STR02479## ##STR02480## ##STR02481## ##STR02482## ##STR02483## ##STR02484## ##STR02485## ##STR02486## ##STR02487## ##STR02488## ##STR02489## ##STR02490## ##STR02491## ##STR02492## ##STR02493## ##STR02494## ##STR02495##

##STR02496## ##STR02497## ##STR02498## ##STR02499## ##STR02500## ##STR02501## ##STR02502## ##STR02503## ##STR02504## ##STR02505## ##STR02506## ##STR02507## ##STR02508## ##STR02509## ##STR02510## ##STR02511## ##STR02512## ##STR02513## ##STR02514## ##STR02515## ##STR02516## ##STR02517## ##STR02518## ##STR02519## ##STR02520## ##STR02521## ##STR02522## ##STR02523## ##STR02524## ##STR02525## ##STR02526## ##STR02527## ##STR02528## ##STR02529## ##STR02530## ##STR02531## ##STR02532## ##STR02533## ##STR02534## ##STR02535## ##STR02536## ##STR02537## ##STR02538## ##STR02539## ##STR02540## ##STR02541## ##STR02542## ##STR02543## ##STR02544## ##STR02545## ##STR02546## ##STR02547## ##STR02548## ##STR02549## ##STR02550## ##STR02551## ##STR02552## ##STR02553## ##STR02554## ##STR02555## ##STR02556## ##STR02557## ##STR02558## ##STR02559## ##STR02560## ##STR02561## ##STR02562##

##STR02563## ##STR02564## ##STR02565## ##STR02566## ##STR02567## ##STR02568## ##STR02569## ##STR02570## ##STR02571## ##STR02572## ##STR02573## ##STR02574## ##STR02575## ##STR02576## ##STR02577## ##STR02578## ##STR02579## ##STR02580## ##STR02581## ##STR02582## ##STR02583## ##STR02584## ##STR02585## ##STR02586## ##STR02587## ##STR02588## ##STR02589## ##STR02590## ##STR02591## ##STR02592## ##STR02593## ##STR02594## ##STR02595## ##STR02596## ##STR02597## ##STR02598## ##STR02599## ##STR02600## ##STR02601## ##STR02602## ##STR02603## ##STR02604## ##STR02605## ##STR02606## ##STR02607## ##STR02608## ##STR02609## ##STR02610##

##STR02611## ##STR02612## ##STR02613## ##STR02614## ##STR02615## ##STR02616## ##STR02617## ##STR02618## ##STR02619## ##STR02620## ##STR02621## ##STR02622## ##STR02623## ##STR02624## ##STR02625## ##STR02626## ##STR02627## ##STR02628## ##STR02629## ##STR02630## ##STR02631## ##STR02632## ##STR02633## ##STR02634## ##STR02635## ##STR02636## ##STR02637## ##STR02638## ##STR02639## ##STR02640## ##STR02641## ##STR02642## ##STR02643## ##STR02644## ##STR02645## ##STR02646## ##STR02647## ##STR02648## ##STR02649## ##STR02650## ##STR02651## ##STR02652## ##STR02653## ##STR02654## ##STR02655## ##STR02656## ##STR02657## ##STR02658## ##STR02659## ##STR02660## ##STR02661## ##STR02662## ##STR02663## ##STR02664## ##STR02665## ##STR02666## ##STR02667## ##STR02668## ##STR02669##

##STR02670## ##STR02671## ##STR02672## ##STR02673## ##STR02674## ##STR02675## ##STR02676## ##STR02677## ##STR02678## ##STR02679## ##STR02680## ##STR02681## ##STR02682## ##STR02683## ##STR02684## ##STR02685## ##STR02686## ##STR02687## ##STR02688## ##STR02689## ##STR02690## ##STR02691## ##STR02692##

[0390] In one or more embodiments, the sensitizer may be represented by Formula 101 or Formula 102, and in this case, the sensitizer may be referred to as a delayed fluorescence sensitizer.

##STR02693## [0391] wherein, in Formulae 101 and 102, [0392] A.sub.21 may be an acceptor group, [0393] D.sub.21 may be a donor group, [0394] m21 may be 1, 2, or 3, and n21 may be 1, 2, or 3, [0395] the sum of n21 and m21 in Formula 101 may be less than or equal to 6, and the sum of n21 and m21 in Formula 102 may be less than or equal to 5, [0396] R.sub.21 may be hydrogen, deuterium, —F, —Cl, —Br, —I, SF.sub.5, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a substituted or unsubstituted C.sub.1-C.sub.60 alkyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkenyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkynyl group, a substituted or unsubstituted C.sub.1-C.sub.60 alkoxy group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenyl group, a substituted or unsubstituted C.sub.2-C.sub.10 heterocycloalkenyl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.7-C.sub.60 alkylaryl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryloxy group, a substituted or unsubstituted C.sub.6-C.sub.60 arylthio group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroalkylaryl group, a substituted or unsubstituted C.sub.2-C.sub.60 heteroaryl alkyl group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryloxy group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroarylthio group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q.sub.1)(Q.sub.2)(Q.sub.3), —Ge(Q.sub.1)(Q.sub.2)(Q.sub.3), —B(Q.sub.1)(Q.sub.2), —N(Q.sub.1)(Q.sub.2), —P(Q.sub.1)(Q.sub.2), —C(═O)(Q.sub.1), —S(═O)(Q.sub.1), —S(═O).sub.2(Q.sub.1), —P(═O)(Q.sub.1)(Q.sub.2), or —P(═S)(Q.sub.1)(Q.sub.2), wherein a plurality of R.sub.21 may optionally be linked to each other to form a substituted or unsubstituted C.sub.5-C.sub.30 carbocyclic group or a substituted or unsubstituted C.sub.1-C.sub.30 heterocyclic group, and [0397] Q.sub.1 to Q.sub.3 may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, a C.sub.1-C.sub.60 alkoxy group, a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.2-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.7-C.sub.60 alkylaryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a C.sub.2-C.sub.60 heteroalkylaryl group, a C.sub.1-C.sub.60 heteroaryloxy group, a C.sub.1-C.sub.60 heteroarylthio group, a monovalent aromatic condensed polycyclic group, a monovalent aromatic condensed heteropolycyclic group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a C.sub.1-C.sub.60 alkyl group that is substituted with at least one deuterium, —F, a cyano group, a C.sub.1-C.sub.60 alkyl group, a C.sub.6-C.sub.60 aryl group, or a combination thereof, or a C.sub.6-C.sub.60 aryl group that is substituted with deuterium, —F, a cyano group, a C.sub.1-C.sub.60 alkyl group, a C.sub.6-C.sub.60 aryl group, or a combination thereof.

[0398] For example, A.sub.21 in Formulae 101 and 102 may be a substituted or unsubstituted π electron-deficient nitrogen-free cyclic group.

[0399] In an embodiment, the π electron-deficient nitrogen-free cyclic group may be a benzene group, a heptalene group, an indene group, a naphthalene group, an azulene group, an indacene group, an acenaphthylene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pentacene group, a hexacene group, a pentacene group, a rubicene group, a coragen group, an ovalene group, a pyrrole group, an isoindole group, an indole group, a furan group, a thiophene group, a benzofuran group, a benzothiophene group, a benzocarbazole group, a dibenzocarbazole group, a dibenzofuran group, a dibenzothiophene group, a dibenzothiophene sulfone group, a carbazole group, a dibenzosilole group, an indenocarbazole group, an indolocarbazole group, a benzofurocarbazole group, a benzothienocarbazole group, a triindolobenzene group; or a condensed cyclic group of two or more π electron-deficient nitrogen-free cyclic groups, but embodiments of the present disclosure are not limited thereto.

[0400] For example, D.sub.21 in Formulae 101 and 102 may be: —F, a cyano group, or a π-electron-deficient nitrogen-containing cyclic group; [0401] a C.sub.1-C.sub.60 alkyl group, an π-electron deficient nitrogen-containing cyclic group, or an π electron-deficient nitrogen-free cyclic group, each substituted with at least one —F, a cyano group, or a combination thereof; or [0402] an π-electron deficient nitrogen-containing cyclic group, each substituted with at least one deuterium, a C.sub.1-C.sub.60 alkyl group, an π-electron deficient nitrogen-containing cyclic group, an π electron-deficient nitrogen-free cyclic group, or a combination thereof.

[0403] In an embodiment, the π electron-deficient nitrogen-free cyclic group is the same as described above.

[0404] The term “π electron-deficient nitrogen-containing cyclic group” used herein refers to a cyclic group having at least one *—N=*′ moiety, and, for example, may be an imidazole group, a pyrazole group, a thiazole group, an isothiazole group, an oxazole group, an isoxazole group, a pyridine group, a pyrazine group, a pyridazine group, a pyrimidine group, an indazole group, a purine group, a quinoline group, an isoquinoline group, a benzoquinoline group, a phthalazine group, a naphthyridine group, a quinoxaline group, a quinazoline group, a cinnoline group, a phenanthridine group, an acridine group, a phenanthroline group, a phenazine group, a benzimidazole group, an isobenzothiazole group, a benzoxazole group, an isobenzoxazole group, a triazole group, a tetrazole group, an oxadiazole group, a triazine group, a thiadiazole group, an imidazopyridine group, an imidazopyrimidine group, an azacarbazole group, a benzimidazolobenzimidazole group; or a condensed cyclic group in which two or more π electron-deficient nitrogen-containing cyclic groups are condensed with each other.

[0405] In one or more embodiments, the sensitizer may be a compound of Groups XI to XV, but embodiments of the present disclosure are not limited thereto:

##STR02694## ##STR02695## ##STR02696## ##STR02697## ##STR02698## ##STR02699## ##STR02700## ##STR02701## ##STR02702## ##STR02703## ##STR02704## ##STR02705## ##STR02706## ##STR02707## ##STR02708## ##STR02709## ##STR02710## ##STR02711## ##STR02712## ##STR02713## ##STR02714## ##STR02715## ##STR02716## ##STR02717## ##STR02718## ##STR02719## ##STR02720## ##STR02721## ##STR02722## ##STR02723## ##STR02724##

##STR02725## ##STR02726## ##STR02727## ##STR02728## ##STR02729## ##STR02730## ##STR02731## ##STR02732## ##STR02733## ##STR02734## ##STR02735## ##STR02736## ##STR02737## ##STR02738## ##STR02739## ##STR02740## ##STR02741## ##STR02742## ##STR02743## ##STR02744## ##STR02745## ##STR02746## ##STR02747## ##STR02748## ##STR02749## ##STR02750## ##STR02751## ##STR02752## ##STR02753## ##STR02754## ##STR02755## ##STR02756## ##STR02757## ##STR02758## ##STR02759## ##STR02760##

##STR02761## ##STR02762## ##STR02763## ##STR02764## ##STR02765## ##STR02766## ##STR02767## ##STR02768## ##STR02769## ##STR02770## ##STR02771## ##STR02772## ##STR02773## ##STR02774## ##STR02775## ##STR02776## ##STR02777## ##STR02778## ##STR02779## ##STR02780## ##STR02781## ##STR02782## ##STR02783## ##STR02784## ##STR02785## ##STR02786## ##STR02787## ##STR02788## ##STR02789## ##STR02790## ##STR02791## ##STR02792## ##STR02793## ##STR02794## ##STR02795## ##STR02796## ##STR02797## ##STR02798## ##STR02799## ##STR02800## ##STR02801## ##STR02802## ##STR02803## ##STR02804## ##STR02805##

##STR02806## ##STR02807## ##STR02808## ##STR02809## ##STR02810## ##STR02811## ##STR02812## ##STR02813## ##STR02814## ##STR02815## ##STR02816## ##STR02817## ##STR02818## ##STR02819## ##STR02820## ##STR02821## ##STR02822## ##STR02823## ##STR02824## ##STR02825## ##STR02826## ##STR02827## ##STR02828## ##STR02829## ##STR02830## ##STR02831## ##STR02832## ##STR02833## ##STR02834## ##STR02835## ##STR02836## ##STR02837## ##STR02838## ##STR02839## ##STR02840## ##STR02841## ##STR02842## ##STR02843## ##STR02844## ##STR02845## ##STR02846## ##STR02847## ##STR02848## ##STR02849## ##STR02850## ##STR02851## ##STR02852## ##STR02853## ##STR02854## ##STR02855##

##STR02856## ##STR02857## ##STR02858## ##STR02859## ##STR02860## ##STR02861## ##STR02862## ##STR02863## ##STR02864## ##STR02865## ##STR02866## ##STR02867## ##STR02868## ##STR02869## ##STR02870## ##STR02871## ##STR02872## ##STR02873## ##STR02874## ##STR02875## ##STR02876## ##STR02877## ##STR02878## ##STR02879## ##STR02880## ##STR02881## ##STR02882## ##STR02883## ##STR02884## ##STR02885## ##STR02886## ##STR02887## ##STR02888## ##STR02889## ##STR02890## ##STR02891## ##STR02892## ##STR02893## ##STR02894## ##STR02895## ##STR02896## ##STR02897## ##STR02898## ##STR02899## ##STR02900## ##STR02901## ##STR02902## ##STR02903## ##STR02904## ##STR02905## ##STR02906## ##STR02907## ##STR02908## ##STR02909## ##STR02910## ##STR02911## ##STR02912## ##STR02913## ##STR02914## ##STR02915## ##STR02916## ##STR02917## ##STR02918## ##STR02919## ##STR02920## ##STR02921##

##STR02922## ##STR02923## ##STR02924## ##STR02925## ##STR02926## ##STR02927## ##STR02928## ##STR02929## ##STR02930## ##STR02931## ##STR02932## ##STR02933## ##STR02934## ##STR02935## ##STR02936## ##STR02937## ##STR02938## ##STR02939## ##STR02940## ##STR02941## ##STR02942## ##STR02943## ##STR02944## ##STR02945## ##STR02946##

##STR02947## ##STR02948## ##STR02949## ##STR02950## ##STR02951## ##STR02952## ##STR02953## ##STR02954## ##STR02955## ##STR02956## ##STR02957## ##STR02958## ##STR02959## ##STR02960## ##STR02961## ##STR02962## ##STR02963## ##STR02964## ##STR02965## ##STR02966## ##STR02967## ##STR02968## ##STR02969## ##STR02970## ##STR02971## ##STR02972## ##STR02973## ##STR02974## ##STR02975## ##STR02976## ##STR02977## ##STR02978## ##STR02979## ##STR02980## ##STR02981## ##STR02982## ##STR02983## ##STR02984## ##STR02985## ##STR02986## ##STR02987## ##STR02988## ##STR02989## ##STR02990## ##STR02991## ##STR02992## ##STR02993## ##STR02994## ##STR02995## ##STR02996## ##STR02997## ##STR02998## ##STR02999## ##STR03000## ##STR03001##

##STR03002## ##STR03003## ##STR03004## ##STR03005## ##STR03006## ##STR03007## ##STR03008## ##STR03009## ##STR03010## ##STR03011## ##STR03012## ##STR03013## ##STR03014## ##STR03015## ##STR03016## ##STR03017## ##STR03018## ##STR03019## ##STR03020## ##STR03021## ##STR03022## ##STR03023## ##STR03024## ##STR03025## ##STR03026## ##STR03027## ##STR03028## ##STR03029## ##STR03030## ##STR03031## ##STR03032## ##STR03033## ##STR03034## ##STR03035## ##STR03036## ##STR03037## ##STR03038## ##STR03039## ##STR03040## ##STR03041## ##STR03042## ##STR03043## ##STR03044## ##STR03045## ##STR03046## ##STR03047## ##STR03048## ##STR03049## ##STR03050## ##STR03051## ##STR03052## ##STR03053## ##STR03054## ##STR03055## ##STR03056## ##STR03057## ##STR03058## ##STR03059## ##STR03060## ##STR03061## ##STR03062## ##STR03063## ##STR03064## ##STR03065## ##STR03066## ##STR03067## ##STR03068## ##STR03069## ##STR03070## ##STR03071## ##STR03072## ##STR03073## ##STR03074## ##STR03075## ##STR03076## ##STR03077## ##STR03078## ##STR03079## ##STR03080## ##STR03081## ##STR03082## ##STR03083## ##STR03084## ##STR03085## ##STR03086## ##STR03087## ##STR03088## ##STR03089## ##STR03090## ##STR03091## ##STR03092##

##STR03093## ##STR03094## ##STR03095## ##STR03096## ##STR03097## ##STR03098## ##STR03099## ##STR03100## ##STR03101## ##STR03102## ##STR03103## ##STR03104## ##STR03105## ##STR03106## ##STR03107## ##STR03108## ##STR03109## ##STR03110## ##STR03111## ##STR03112## ##STR03113## ##STR03114## ##STR03115## ##STR03116## ##STR03117## ##STR03118## ##STR03119## ##STR03120## ##STR03121## ##STR03122## ##STR03123## ##STR03124## ##STR03125## ##STR03126## ##STR03127## ##STR03128## ##STR03129## ##STR03130## ##STR03131## ##STR03132## ##STR03133## ##STR03134## ##STR03135## ##STR03136## ##STR03137## ##STR03138## ##STR03139## ##STR03140## ##STR03141## ##STR03142## ##STR03143## ##STR03144## ##STR03145## ##STR03146## ##STR03147## ##STR03148## ##STR03149## ##STR03150## ##STR03151## ##STR03152## ##STR03153## ##STR03154## ##STR03155## ##STR03156## ##STR03157## ##STR03158## ##STR03159## ##STR03160## ##STR03161## ##STR03162## ##STR03163## ##STR03164## ##STR03165##

##STR03166## ##STR03167## ##STR03168## ##STR03169## ##STR03170## ##STR03171## ##STR03172## ##STR03173## ##STR03174## ##STR03175## ##STR03176## ##STR03177## ##STR03178## ##STR03179## ##STR03180## ##STR03181## ##STR03182## ##STR03183## ##STR03184## ##STR03185## ##STR03186## ##STR03187## ##STR03188## ##STR03189## ##STR03190## ##STR03191## ##STR03192## ##STR03193## ##STR03194## ##STR03195## ##STR03196## ##STR03197## ##STR03198## ##STR03199## ##STR03200##

[0406] Hole Transport Region 12

[0407] The hole transport region 12 may be arranged between the first electrode 11 and the emission layer 15 of the organic light-emitting device 10.

[0408] The hole transport region 12 may have a single-layer structure or a multi-layer structure.

[0409] For example, the hole transport region 12 may have a hole injection layer, a hole transport layer, a hole injection layer/hole transport layer structure, a hole injection layer/first hole transport layer/second hole transport layer structure, a hole transport layer/interlayer structure, a hole injection layer/hole transport layer/interlayer structure, a hole transport layer/electron blocking layer structure, or a hole injection layer/hole transport layer/electron blocking layer structure, but embodiments of the present disclosure are not limited thereto.

[0410] The hole transport region 12 may include any compound having hole-transporting properties.

[0411] For example, the hole transport region 12 may include an amine-based compound.

[0412] In an embodiment, the hole transport region 1 may include at least one a compound represented by Formula 201 to a compound represented by Formula 205, but embodiments of the present disclosure are not limited thereto:

##STR03201## [0413] wherein, in Formulae 201 to 205, [0414] L.sub.201 to L.sub.209 may each independently *-be O—*′, *—S—*′, a substituted or unsubstituted [0415] C.sub.5-C.sub.60 carbocyclic group, or a substituted or unsubstituted C.sub.1-C.sub.60 heterocyclic group, [0416] xa1 to xa9 may each independently be an integer from 0 to 5, and [0417] R.sub.201 to R.sub.206 may each independently be a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted heterocycloalkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenyl group, a substituted or unsubstituted C.sub.2-C.sub.10 heterocycloalkenyl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryloxy group, a substituted or unsubstituted C.sub.6-C.sub.60 arylthio group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted monovalent aromatic condensed polycyclic group, a substituted or unsubstituted monovalent aromatic condensed heteropolycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, and two adjacent groups R.sub.201 to R.sub.206 may optionally be bound via a single bond, a dimethyl-methylene group, or a diphenyl-methylene group.

[0418] For example, L.sub.201 to L.sub.209 may be: [0419] a benzene group, a heptalene group, an indene group, a naphthalene group, an azulene group, a heptalene group, an indacene group, an acenaphthylene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pentacene group, a hexacene group, a pentacene group, a rubicene group, a coragen group, an ovalene group, a pyrrole group, an isoindole group, an indole group, a furan group, a thiophene group, a benzofuran group, a benzothiophene group, a benzocarbazole group, a dibenzocarbazole group, a dibenzofuran group, a dibenzothiophene group, a dibenzothiophene sulfone group, a carbazole group, a dibenzosilole group, an indenocarbazole group, an indolocarbazole group, a benzofurocarbazole group, a benzothienocarbazole group, and a triindolobenzene group, each unsubstituted or substituted with deuterium, a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group, a phenyl group, a naphthyl group, a fluorenyl group, a carbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a triphenylenyl group, a biphenyl group, a terphenyl group, a tetraphenyl group, or —Si(Q.sub.11)(Q.sub.12)(Q.sub.13), [0420] xa1 to xa9 may each independently be 0, 1, or 2, and [0421] R.sub.201 to R.sub.206 may each independently be a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, an indeno carbazolyl group, an indolocarbazolyl group, a benzofurocarbazolyl group, or a benzothienocarbazolyl group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a phenyl group substituted with a C.sub.1-C.sub.10 alkyl group, a phenyl group substituted with —F, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, —Si(Q.sub.31)(Q.sub.32)(Q.sub.33), —N(Q.sub.31)(Q.sub.32), or a combination thereof, [0422] wherein Q.sub.11 to Q.sub.13 and Q.sub.31 to Q.sub.33 may each independently be a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, or a naphthyl group.

[0423] In one or more embodiments, the hole transport region 12 may include a carbazole-containing amine-based compound.

[0424] In an embodiment, the hole transport region 12 may include a carbazole-containing amine-based compound or a carbazole-free amine-based compound.

[0425] The carbazole-containing amine-based compound may be, for example, a compound represented by Formula 201 including a carbazole group and further including at least one of a dibenzofuran group, a dibenzothiophene group, a fluorene group, a spiro-bifluorene group, an indenocarbazole group, an indolocarbazole group, a benzofurocarbazole group, a benzothienocarbazole group, or a combination thereof.

[0426] The carbazole-free amine-based compound may be, for example, a compound represented by Formula 201 which do not include a carbazole group and which include at least one a dibenzofuran group, a dibenzothiophene group, a fluorene group, a spiro-bifluorene group, an indenocarbazole group, an indolocarbazole group, a benzofurocarbazole group, a benzothienocarbazole group, or a combination thereof.

[0427] In one or more embodiments, the hole transport region 12 may include at least one compound represented by Formulae 201 or 202.

[0428] In an embodiment, the hole transport region 12 may include at least one compound represented by Formulae 201-1, 202-1 or 201-2, but embodiments of the present disclosure are not limited thereto:

##STR03202##

[0429] In Formulae 201-1, 202-1, and 201-2, L.sub.201 to L.sub.203, L.sub.205, xa1 to xa3, xa5, R.sub.201 and R.sub.202 are the same as described herein, and R.sub.211 to R.sub.213 are each independently hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a phenyl group substituted with a C.sub.1-C.sub.10 alkyl group, a phenyl group substituted with —F, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a dimethylfluorenyl group, a diphenylfluorenyl group, a triphenylenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, or a combination thereof.

[0430] For example, the hole transport region 12 may include at least one of Compounds HT1 to HT39, but embodiments of the present disclosure are not limited thereto.

##STR03203## ##STR03204## ##STR03205## ##STR03206## ##STR03207## ##STR03208## ##STR03209## ##STR03210## ##STR03211## ##STR03212##

[0431] In one or more embodiments, the hole transport region 12 may include at least one of 4,4′-cyclohexylidenebis[N,N-bis(4-methylphenyl)benzenamine] (TAPC), tris(4-carbazoyl-9-ylphenyl)amine (TCTA), or a combination thereof.

[0432] In one or more embodiments, hole transport region 12 of the organic light-emitting device 10 may further include a p-dopant. When the hole transport region 12 further includes a p-dopant, the hole transport region 12 may have a matrix (for example, at least one of compounds represented by Formulae 201 to 205) and a p-dopant included in the matrix. The p-dopant may be uniformly or non-uniformly doped in the hole transport region 12.

[0433] In an embodiment, the LUMO energy level of the p-dopant may be about −3.5 eV or less.

[0434] The p-dopant may include at least one of a quinone derivative, a metal oxide, a cyano group-containing compound, or a combination thereof, but embodiments of the present disclosure are not limited thereto.

[0435] In an embodiment, the p-dopant may include at least one of: [0436] a quinone derivative, such as tetracyanoquinodimethane (TCNQ),2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), and F6-TCNNQ; [0437] a metal oxide, such as tungsten oxide or molybdenum oxide; 1,4,5,8,9,12-hexaazatriphenylene-hexacarbonitrile (HAT-CN); [0438] a compound represented by Formula 221, [0439] or a combination thereof, [0440] but embodiments of the present disclosure are not limited thereto:

##STR03213## [0441] wherein, in Formula 221, [0442] R.sub.221 to R.sub.223 may each independently be a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenyl group, a substituted or unsubstituted C.sub.2-C.sub.10 heterocycloalkenyl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryl group, a substituted or unsubstituted monovalent aromatic condensed polycyclic group, a substituted or unsubstituted monovalent aromatic condensed heteropolycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, or a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, wherein at least one of R.sub.221 to R.sub.223 may include at least one substituent of a cyano group, —F, —Cl, —Br, —I, a C.sub.1-C.sub.20 alkyl group substituted with —F, a C.sub.1-C.sub.20 alkyl group substituted with —Cl, a C.sub.1-C.sub.20 alkyl group substituted with —Br, a C.sub.1-C.sub.20 alkyl group substituted with —I, or a combination thereof.

[0443] The hole transport region 12 may have a thickness of about 100 Å to about 10,000 Å, for example, about 400 Å to about 2,000 Å, and the emission layer 15 may have a thickness of about 100 Å to about 3,000 Å, for example, about 300 Å to about 1,000 Å. When the thickness of each of the hole transport region 12 and the emission layer 15 is within these ranges, satisfactory hole transportation characteristics and/or luminescence characteristics may be obtained without a substantial increase in driving voltage.

[0444] Electron Transport Region 17

[0445] The electron transport region 17 may be arranged between the emission layer 15 and the second electrode 19 of the organic light-emitting device 10.

[0446] The electron transport region 17 may have a single-layer structure or a multi-layer structure.

[0447] For example, the electron transport region 17 may have an electron transport layer, an electron transport layer/electron injection layer structure, a buffer layer/electron transport layer structure, hole blocking layer/electron transport layer structure, a buffer layer/electron transport layer/electron injection layer structure, or a hole blocking layer/electron transport layer/electron injection layer structure. The electron transport region 17 may further include an electron control layer.

[0448] The electron transport region 17 may include a known electron-transporting material.

[0449] The electron transport region 17 (for example, a buffer layer, a hole blocking layer, an electron control layer, or an electron transport layer in the electron transport region) may include a metal-free compound containing at least one π electron-deficient nitrogen-containing cyclic group. The π electron-deficient nitrogen-containing cyclic group is the same as described above.

[0450] In an embodiment, the electron transport region may include a compound represented by Formula 601 below:

[Ar.sub.601].sub.xe11-[(L.sub.601).sub.xe1-R.sub.601].sub.xe21  Formula 601 [0451] wherein, in Formula 601, [0452] Ar.sub.601 and L.sub.601 may each independently be a substituted or unsubstituted C.sub.5-C.sub.60 carbocyclic group or a substituted or unsubstituted C.sub.1-C.sub.60 heterocyclic group, [0453] xe11 may be 1, 2, or 3, [0454] xe1 may be an integer from 0 to 5, [0455] R.sub.601 may be a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenyl group, a substituted or unsubstituted C.sub.2-C.sub.10 heterocycloalkenyl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryloxy group, a substituted or unsubstituted C.sub.6-C.sub.60 arylthio group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted monovalent aromatic condensed polycyclic group, a substituted or unsubstituted monovalent aromatic condensed heteropolycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —Si(Q.sub.601)(Q.sub.602)(Q.sub.603), —C(═O)(Q.sub.601), —S(═O).sub.2(Q.sub.601), or —P(═O)(Q.sub.601)(Q.sub.602), [0456] Q.sub.601 to Q.sub.603 may each independently be a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, or a naphthyl group, and [0457] xe21 may be an integer from 1 to 5.

[0458] In an embodiment, at least one of Ar.sub.601(s) in the number of xe11 and R.sub.601(s) in the number of xe21 may include the π electron-deficient nitrogen-containing cyclic group.

[0459] In an embodiment, ring Ar.sub.601 and L.sub.601 in Formula 601 may each independently be a benzene group, a naphthalene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pentaphene group, an indenoanthracene group, a dibenzofuran group, a dibenzothiophene group, a carbazole group, an imidazole group, a pyrazole group, a thiazole group, an isothiazole group, an oxazole group, an isoxazole group, a pyridine group, a pyrazine group, a pyrimidine group, a pyridazine group, an indazole group, a purine group, a quinoline group, an isoquinoline group, a benzoquinoline group, a phthalazine group, a naphthyridine group, a quinoxaline group, a quinazoline group, a cinnoline group, a phenanthridine group, an acridine group, a phenanthroline group, a phenazine group, a benzimidazole group, an isobenzothiazole group, a benzoxazole group, an isobenzoxazole group, a triazole group, a tetrazole group, an oxadiazole group, a triazine group, a thiadiazole group, an imidazopyridine group, an imidazopyrimidine group, or an azacarbazole group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, —Si(Q.sub.31)(Q.sub.32)(Q.sub.33), —S(═O).sub.2(Q.sub.31), —P(═O)(Q.sub.31)(Q.sub.32), or a combination thereof, and [0460] Q.sub.31 to Q.sub.33 may each independently be a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, or a naphthyl group.

[0461] When xe11 in Formula 601 is 2 or greater, two or more of Ar.sub.601 may be linked to each other via a single bond.

[0462] In one or more embodiments, Ar.sub.601 in Formula 601 may be an anthracene group.

[0463] In one or more embodiments, the compound represented by Formula 601 may be represented by Formula 601-1:

##STR03214## [0464] wherein, in Formula 601-1, [0465] X.sub.614 may be N or C(R.sub.614), X.sub.615 may be N or C(R.sub.615), X.sub.616 may be N or C(R.sub.616), and at least one of X.sub.614 to X.sub.616 may be N, [0466] L.sub.611 to L.sub.613 may each independently be the same as described in connection with L.sub.601, [0467] xe611 to xe613 may each independently be the same as described in connection with xe1, [0468] R.sub.611 to R.sub.613 may each independently be the same as described in connection with R.sub.601, and [0469] R.sub.614 to R.sub.616 may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, or a naphthyl group.

[0470] In one or more embodiments, xe1 and xe611 to xe613 in Formulae 601 and 601-1 may each independently be 0, 1, or 2.

[0471] In one or more embodiments, R.sub.601 and R.sub.611 to R.sub.613 in Formulae 601 and 601-1 may each independently be a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, or an azacarbazolyl group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, an indolyl group, an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, an azacarbazolyl group, or a combination thereof; or [0472] —S(═O).sub.2(Q.sub.601) or —P(═O)(Q.sub.601)(Q.sub.602), and [0473] Q.sub.601 and Q.sub.602 may each be the same as described in the present specification.

[0474] The electron transport region 17 may include at least one compound of Compounds ET1 to ET36, but embodiments of the present disclosure are not limited thereto:

##STR03215## ##STR03216## ##STR03217## ##STR03218## ##STR03219## ##STR03220## ##STR03221## ##STR03222## ##STR03223## ##STR03224## ##STR03225## ##STR03226##

[0475] In one or more embodiments, the electron transport region 17 may include at least one of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline (Bphen), Alq3, BAlq, 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole (TAZ), 2,2′,2″-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi), NTAZ, or a combination thereof:

##STR03227##

[0476] Thicknesses of the buffer layer, the hole blocking layer, and the electron control layer may each independently be in the range of about 20 Å to about 1,000 Å, for example, about 30 Å to about 300 Å. When the thicknesses of the buffer layer, the hole blocking layer, and the electron control layer are within these ranges, excellent hole blocking characteristics or excellent electron control characteristics may be obtained without a substantial increase in driving voltage.

[0477] A thickness of the electron transport layer may be in the range of about 100 Å to about 1,000 Å, for example, about 150 Å to about 500 Å. When the thickness of the electron transport layer is within the range described above, the electron transport layer may have satisfactory electron transporting characteristics without a substantial increase in driving voltage.

[0478] The electron transport region 17 (for example, the electron transport layer in the electron transport region 17) may further include, in addition to the materials described above, a metal-containing material.

[0479] The metal-containing material may include at least one alkali metal complex, alkaline earth-metal complex, or a combination thereof. The alkali metal complex may include a metal ion a L.sub.1 ion, a Na ion, a K ion, a Rb ion, a Cs ion, or a combination thereof, and the alkaline earth-metal complex may include a Be ion, a Mg ion, a Ca ion, a Sr ion, a Ba ion, or a combination thereof. A ligand coordinated with the metal ion of the alkali metal complex or the alkaline earth-metal complex may be a hydroxy quinoline, a hydroxy isoquinoline, a hydroxy benzoquinoline, a hydroxy acridine, a hydroxy phenanthridine, a hydroxy phenyloxazole, a hydroxy phenylthiazole, a hydroxy diphenyloxadiazole, a hydroxy diphenylthiadiazole, a hydroxy phenylpyridine, a hydroxy phenylbenzimidazole, a hydroxy phenylbenzothiazole, a bipyridine, a phenanthroline, or a cyclopentadiene, but embodiments of the present disclosure are not limited thereto.

[0480] In an embodiment, the metal-containing material may include a L.sub.1 complex. The Li complex may include, for example, Compound ET-D1 (lithium quinolate, LiQ) or ET-D2:

##STR03228##

[0481] The electron transport region 17 may include an electron injection layer that facilitates the injection of electrons from the second electrode 19. The electron injection layer may directly contact the second electrode 19.

[0482] The electron injection layer may have i) a single-layer structure consisting of a single layer including a single material, ii) a single-layer structure consisting of a single layer including multiple materials that are different from each other, or iii) a multi-layer structure consisting of multiple layers including multiple different materials that are different from each other.

[0483] The electron injection layer may include an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal compound, an alkaline earth-metal compound, a rare earth metal compound, an alkali metal complex, an alkaline earth-metal complex, a rare earth metal complex, or any combination thereof.

[0484] The alkali metal may be Li, Na, K, Rb, or Cs. In an embodiment, the alkali metal may be Li, Na, or Cs. In one or more embodiments, the alkali metal may be L.sub.1 or Cs, but embodiments of the present disclosure are not limited thereto.

[0485] The alkaline earth metal may be Mg, Ca, Sr, or Ba.

[0486] The rare earth metal may be Sc, Y, Ce, Tb, Yb, or Gd.

[0487] The alkali metal compound, the alkaline earth-metal compound, and the rare earth metal compound may be an oxide or a halide (for example, fluorides, chlorides, bromides, or iodides) of the alkali metal, the alkaline earth-metal, and the rare earth metal.

[0488] The alkali metal compound may be an alkali metal oxide, such as Li.sub.2O, Cs.sub.2O, or K.sub.2O, and alkali metal halides, such as LiF, NaF, CsF, KF, LiI, NaI, CsI, or KI. In an embodiment, the alkali metal compound may be LiF, Li.sub.2O, NaF, LiI, NaI, CsI, or KI, but embodiments of the present disclosure are not limited thereto.

[0489] The alkaline earth-metal compound may be alkaline earth-metal oxides, such as BaO, SrO, CaO, Ba.sub.xSr.sub.1-xO (0<x<1), or Ba.sub.xCa.sub.1-xO (0<x<1). In an embodiment, the alkaline earth-metal compound may be BaO, SrO, or CaO, but embodiments of the present disclosure are not limited thereto.

[0490] The rare earth metal compound may be YbF.sub.3, ScF.sub.3, ScO.sub.3, Y.sub.2O.sub.3, Ce.sub.2O.sub.3, GdF.sub.3, TbF.sub.3. In an embodiment, the rare earth metal compound may be YbF.sub.3, ScF.sub.3, TbF.sub.3, YbI.sub.3, ScI.sub.3, or TbI.sub.3, but embodiments of the present disclosure are not limited thereto.

[0491] The alkali metal complex, the alkaline earth-metal complex, and the rare earth metal complex may include an ion of alkali metal, alkaline earth-metal, or rare earth metal as described above, and a ligand coordinated with a metal ion of the alkali metal complex, the alkaline earth-metal complex, or the rare earth metal complex may be hydroxy quinoline, hydroxy isoquinoline, hydroxy benzoquinoline, hydroxy acridine, hydroxy phenanthridine, hydroxy phenyloxazole, hydroxy phenylthiazole, hydroxy diphenyloxadiazole, hydroxy diphenylthiadiazole, hydroxy phenylpyridine, hydroxy phenylbenzimidazole, hydroxy phenylbenzothiazole, bipyridine, phenanthroline, or cyclopentadiene, but embodiments of the present disclosure are not limited thereto.

[0492] The electron injection layer may consist of an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal compound, an alkaline earth-metal compound, a rare earth metal compound, an alkali metal complex, an alkaline earth-metal complex, a rare earth metal complex, or any combination thereof, as described above. In one or more embodiments, the electron injection layer may further include an organic material. When the electron injection layer further includes an organic material, an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal compound, an alkaline earth-metal compound, a rare earth metal compound, an alkali metal complex, an alkaline earth-metal complex, a rare earth metal complex, or any combination thereof may be homogeneously or non-homogeneously dispersed in a matrix including the organic material.

[0493] A thickness of the electron injection layer may be in a range of about 1 Å to about 100 Å, and, for example, about 3 Å to about 90 Å. When the thickness of the electron injection layer is within the ranges above, satisfactory electron injection characteristics may be obtained without a substantial increase in driving voltage.

[0494] Second Electrode 19

[0495] The second electrode 19 is arranged on the organic layer 10A having such a structure. The second electrode 19 may be a cathode which is an electron injection electrode, and in this regard, a material for forming the second electrode 19 may be a metal, an alloy, an electrically conductive compound, or a combination thereof, which have a relatively low work function.

[0496] The second electrode 19 may include at least one lithium (Li), silver (Ag), magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), magnesium-silver (Mg—Ag), ITO, IZO, or a combination thereof, but embodiments of the present disclosure are not limited thereto. The second electrode 19 may be a transmissive electrode, a semi-transmissive electrode, or a reflective electrode.

[0497] The second electrode 19 may have a single-layer structure having a single layer or a multi-layer structure including two or more layers.

[0498] Hereinbefore, the organic light-emitting device has been described with reference to FIG. 1, but embodiments of the present disclosure are not limited thereto.

[0499] Description of FIG. 2

[0500] FIG. 2 is a schematic view of an organic light-emitting device 100 according to an exemplary embodiment.

[0501] The organic light-emitting device 100 of FIG. 2 includes a first electrode 110, a second electrode 190 facing the first electrode 110, and a first light-emitting unit 151 and a second light-emitting unit 152 between the first electrode 110 and the second electrode 190. A charge generation layer 141 is arranged between the first emission unit 151 and the second emission unit 152, and the charge generation layer 141 may include an n-type charge generation layer 141-N and a p-type charge generation layer 141-P. The charge generation layer 141 is a layer that generates charge and supplies the charge to neighboring emission units, and any known material may be used therefor.

[0502] The first light-emitting unit 151 may include a first emission layer 151-EM, and the second light-emitting unit 152 may include a second emission layer 152-EM. The maximum emission wavelength of light emitted from the first light-emitting unit 151 may be different from the maximum emission wavelength of light emitted from the second light-emitting unit 152. For example, the mixed light including the light emitted from the first light-emitting unit 151 and the light emitted from the second light-emitting unit 152 may be white light, but embodiments of the present disclosure are not limited thereto.

[0503] The hole transport region 120 is arranged between the first light-emitting unit 151 and the first electrode 110, and the second light-emitting unit 152 may include the first hole transport region 121 arranged on the side of the first electrode 110.

[0504] An electron transport region 170 is arranged between the second light-emitting unit 152 and the second electrode 190, and the first emission unit 151 may include a first electron transport region 171 arranged between the charge generation layer 141 and the first emission layer 151-EM.

[0505] The first emission layer 151-EM may include the heterocyclic compound.

[0506] The second emission layer 152-EM may include the heterocyclic compound.

[0507] The first electrode 110 and the second electrode 190 in FIG. 2 may respectively be the same as described in connection with the first electrode 11 and the second electrode 19 in FIG. 1.

[0508] In FIG. 2, the first emission layer 151-EM and the second emission layer 152-EM may each be understood by referring to the description for the emission layer 15 in FIG. 1.

[0509] The hole transport region 120 and the first hole transport region 121 in FIG. 2 are each the same as described in connection with the hole transport region 12 in FIG. 1.

[0510] The electron transport region 170 and the first electron transport region 171 in FIG. 2 are each the same as described in connection with the electron transport region 17 in FIG. 1.

[0511] As described above, referring to FIG. 2, an organic light-emitting device in which each of the first light-emitting unit 151 and the second light-emitting unit 152 includes an emission layer including a host, a dopant, and a sensitizer, has been described. However, the organic light-emitting device may have various other forms. For example, one of the first light-emitting unit 151 and the second light-emitting unit 152 of the organic light-emitting device 100 of FIG. 2 may be replaced with any known light-emitting unit, or may include three or more light-emitting units.

[0512] Description of FIG. 3

[0513] FIG. 3 is a schematic cross-sectional view of an organic light-emitting device 200 according to another exemplary embodiment.

[0514] The organic light-emitting device 200 includes a first electrode 210, a second electrode 290 facing the first electrode 210, and a first emission layer 251 and a second emission layer 252 which are stacked between the first electrode 210 and the second electrode 290.

[0515] A maximum emission wavelength of light emitted from the first emission layer 251 may be different from a maximum emission wavelength of light emitted from the second emission layer 252. For example, the mixed light of the light emitted from the first emission layer 251 and the light emitted from the second emission layer 252 may be white light, but embodiments of the present disclosure are not limited thereto.

[0516] In one or more embodiments, a hole transport region 220 may be arranged between the first emission layer 251 and the first electrode 210, and an electron transport region 270 may be arranged between the second emission layer 252 and the second electrode 290.

[0517] The first emission layer 251 may include the heterocyclic compound.

[0518] The second emission layer 252 may include the heterocyclic compound.

[0519] The first electrode 210, the hole transporting-region 220, and the second electrode 290 in FIG. 3 are respectively the same as described in connection with the first electrode 11, the hole transport region 12, and the second electrode 19 in FIG. 1.

[0520] The first emission layer 251 and the second emission layer 252 in FIG. 3 may each be the same as described in connection with the emission layer 15 in FIG. 1.

[0521] The electron transporting-region 270 in FIG. 3 may be the same as described in connection with the electron transport region 17 in FIG. 1.

[0522] Hereinabove, referring to FIG. 3, the organic light-emitting device in which both the first emission layer 251 and the second emission layer 252 include the heterocyclic compound is described. However, various modifications of embodiments may be available, and for example, any one of the first emission layer 251 and the second emission layer 252 in FIG. 3 may be replaced by a known layer, three or more emission layers may be included, or an interlayer may be additionally arranged between neighboring emission layers.

[0523] Electronic Apparatus

[0524] The organic light-emitting device may be included in various electronic apparatuses.

[0525] The electronic apparatus may further include a thin-film transistor in addition to the organic light-emitting device as described above. The thin-film transistor may include a source electrode, a drain electrode, and an activation layer, wherein any one of the source electrode and the drain electrode may be electrically connected to any one of the first electrode and the second electrode of the organic light-emitting device.

DEFINITION OF TERMS

[0526] The term “C.sub.1-C.sub.60 alkyl group” as used herein refers to a linear or branched saturated aliphatic hydrocarbon monovalent group having 1 to 60 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an isoamyl group, and a hexyl group. The term “C.sub.1-C.sub.60 alkylene group” as used herein refers to a divalent group having the same structure as the C.sub.1-C.sub.60 alkyl group.

[0527] The term “C.sub.1-C.sub.60 alkoxy group” used herein refers to a monovalent group represented by —OA.sub.101 (wherein A.sub.101 is the C.sub.1-C.sub.60 alkyl group), and examples thereof include a methoxy group, an ethoxy group, and an isopropyloxy group.

[0528] The term “C.sub.2-C.sub.60 alkenyl group” as used herein refers to a hydrocarbon group formed by substituting at least one carbon-carbon double bond in the middle or at the terminus of the C.sub.2-C.sub.60 alkyl group, and examples thereof include an ethenyl group, a propenyl group, and a butenyl group. The term “C.sub.2-C.sub.60 alkenylene group” as used herein refers to a divalent group having the same structure as the C.sub.2-C.sub.60 alkenyl group.

[0529] The term “C.sub.2-C.sub.60 alkynyl group” as used herein refers to a hydrocarbon group formed by substituting at least one carbon-carbon triple bond in the middle or at the terminus of the C.sub.2-C.sub.60 alkyl group, and examples thereof include an ethynyl group, and a propynyl group. The term “C.sub.2-C.sub.60 alkynylene group” as used herein refers to a divalent group having the same structure as the C.sub.2-C.sub.60 alkynyl group.

[0530] The term “C.sub.3-C.sub.10 cycloalkyl group” as used herein refers to a monovalent saturated hydrocarbon monocyclic group having 3 to 10 carbon atoms, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group. The term “C.sub.3-C.sub.10 cycloalkylene group” as used herein refers to a divalent group having the same structure as the C.sub.3-C.sub.10 cycloalkyl group.

[0531] The term “C.sub.1-C.sub.10 heterocycloalkyl group” as used herein refers to a monovalent saturated monocyclic group having at least one heteroatom N, O, P, Si, and S as a ring-forming atom and 1 to 10 carbon atoms, and non-limiting examples thereof include a tetrahydrofuranyl group and a tetrahydrothiophenyl group. The term “C.sub.1-C.sub.10 heterocycloalkylene group” as used herein refers to a divalent group having the same structure as the C.sub.1-C.sub.10 heterocycloalkyl group.

[0532] The term “C.sub.3-C.sub.10 cycloalkenyl group” as used herein refers to a monovalent monocyclic group that has 3 to 10 carbon atoms and at least one carbon-carbon double bond in the ring thereof and no aromaticity, and non-limiting examples thereof include a cyclopentenyl group, a cyclohexenyl group, and a cycloheptenyl group. The term “C.sub.3-C.sub.10 cycloalkenylene group” as used herein refers to a divalent group having the same structure as the C.sub.3-C.sub.10 cycloalkenyl group.

[0533] The term “C.sub.2-C.sub.10 heterocycloalkenyl group” as used herein refers to a monovalent monocyclic group that has at least one heteroatom N, O, P, Si, S, B, Ge, Te, or a combination thereof as a ring-forming atom, 2 to 10 carbon atoms, and at least one carbon-carbon double bond in its ring. Examples of the C.sub.2-C.sub.10 heterocycloalkenyl group are a 2,3-dihydrofuranyl group, and a 2,3-dihydrothiophenyl group. The term “C.sub.2-C.sub.10 heterocycloalkenylene group” as used herein refers to a divalent group having the same structure as the C.sub.2-C.sub.10 heterocycloalkenyl group.

[0534] The term “C.sub.6-C.sub.60 aryl group” as used herein refers to a monovalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms, and the term “C.sub.6-C.sub.60 arylene group” as used herein refers to a divalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms. Examples of the C.sub.6-C.sub.60 aryl group include a phenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenyl group, and a chrysenyl group. When the C.sub.6-C.sub.60 aryl group and the C.sub.6-C.sub.60 arylene group each include two or more rings, the rings may be fused to each other.

[0535] The term “C.sub.1-C.sub.60 heteroaryl group” as used herein refers to a monovalent group having a heterocyclic aromatic system that has at least one heteroatom N, O, P, Si, Si, S, B, Ge, Te, or a combination thereof as a ring-forming atom, and 1 to 60 carbon atoms. The term “C.sub.1-C.sub.60 heteroarylene group” as used herein refers to a divalent group having a carbocyclic aromatic system that has at least one heteroatom N, O, P, Si, S, B, Ge, Te, or a combination thereof as a ring-forming atom, and 1 to 60 carbon atoms. Examples of the C.sub.1-C.sub.60 heteroaryl group include a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, and an isoquinolinyl group. When the C.sub.6-C.sub.60 heteroaryl group and the C.sub.6-C.sub.60 heteroarylene group each include two or more rings, the rings may be fused to each other.

[0536] The term “C.sub.6-C.sub.60 aryloxy group” as used herein indicates —OA.sub.102 (wherein A.sub.102 is the C.sub.6-C.sub.60 aryl group), and the term “C.sub.6-C.sub.60 arylthio group” as used herein indicates —SA.sub.103 (wherein A.sub.103 is the C.sub.6-C.sub.60 aryl group).

[0537] The term “monovalent aromatic condensed polycyclic group” as used herein refers to a monovalent group having two or more rings condensed and only carbon atoms (for example, the number of carbon atoms may be in a range of 8 to 60) as ring-forming atoms, wherein the molecular structure as a whole is aromatic. The term “divalent aromatic condensed polycyclic group” as used herein refers to a divalent group having the same structure as the monovalent aromatic condensed polycyclic group described above.

[0538] The term “monovalent aromatic condensed heteropolycyclic group” as used herein refers to a monovalent group having at least two rings condensed and a heteroatom N, O, P, Si, Si, S, B, Ge, Te, or a combination thereof as well as carbon atoms (for example, the number of carbon atoms may be in a range of 1 to 60) as ring-forming atoms, wherein the molecular structure as a whole is aromatic. The term “divalent aromatic condensed heteropolycyclic group” as used herein refers to a divalent group having the same structure as the monovalent aromatic condensed heteropolycyclic group described above.

[0539] The term “monovalent non-aromatic condensed polycyclic group” used herein refers to a monovalent group in which two or more rings are condensed with each other, only carbon is used as a ring-forming atom (for example, the number of carbon atoms may be 8 to 60) and the whole molecule is a non-aromaticity group. Examples of the monovalent non-aromatic condensed polycyclic group include a fluorenyl group. The term “divalent non-aromatic condensed polycyclic group” as used herein refers to a divalent group having the same structure as the monovalent non-aromatic condensed polycyclic group described above.

[0540] The term “monovalent non-aromatic condensed heteropolycyclic group” as used herein refers to a monovalent group having two or more rings condensed to each other, a heteroatom N, O, P, Si, Si, S, B, Ge, Te, or a combination thereof, other than carbon atoms(for example, having 1 to 60 carbon atoms), as a ring-forming atom, and no aromaticity in its entire molecular structure. Examples of the monovalent non-aromatic condensed heteropolycyclic group include a carbazolyl group. The term “divalent non-aromatic condensed heteropolycyclic group” as used herein refers to a divalent group having the same structure as the monovalent non-aromatic condensed heteropolycyclic group described above.

[0541] The term “π electron-depleted nitrogen-containing C.sub.1-C.sub.60 cyclic group” as used herein refers to a cyclic group having 1 to 60 carbon atoms and including at least one *—N=*′ (wherein * and *′ each indicate a binding site to an adjacent atom) as a ring-forming moiety. For example, the π electron-depleted nitrogen-containing C.sub.1-C.sub.60 cyclic group may be a) a first ring, b) a condensed ring in which at least two first rings are condensed, or c) a condensed ring in which at least one first ring and at least one second ring are condensed.

[0542] The term “π electron-rich C.sub.3-C.sub.60 cyclic group” as used herein refers to a cyclic group having 3 to 60 carbon atoms and not including at least one *—N=*′ (wherein * and *′ each indicate a binding site to an adjacent atom) as a ring-forming moiety. For example, the π electron-rich C.sub.3-C.sub.60 cyclic group may be a) a second ring or b) a condensed ring in which at least two second rings are condensed.

[0543] The term “C.sub.5-C.sub.60 carbocyclic group” as used herein refers to a monocyclic or polycyclic group having 5 to 60 carbon atoms, and may be, for example, a) a third ring or b) a condensed ring in which two or more third rings are condensed with each other.

[0544] The term “C.sub.1-C.sub.60 heterocyclic group” as used herein refers to a monocyclic or polycyclic group that has 1 to 60 carbon atoms and includes at least one heteroatom, and may be, for example, a) a fourth ring, b) a condensed ring in which two or more fourth rings are condensed with each other, or c) a condensed ring in which at least one third ring is condensed with at least one fourth ring.

[0545] The “first ring” as used herein may be an imidazole group, a pyrazole group, a thiazole group, an isothiazole group, an oxazole group, an isoxazole group, a pyridine group, a pyrazine group, a pyridazine group, a pyrimidine group, a triazole group, a tetrazole group, an oxadiazole group, a triazine group, or a thiadiazole group.

[0546] The “second ring” as used herein may be a benzene group, a cyclopentadiene group, a pyrrole group, a furan group, a thiophene group, or a silole group.

[0547] The “third ring” as used herein may be a cyclopentane group, a cyclopentadiene group, an indene group, an adamantane group, a norbornene group, a bicyclo[1.1.1]pentane group, a bicyclo[2.1.1]hexane group, a bicyclo[2.2.1]heptane group (a norbornane group), a bicyclo[2.2.2]octane group, a cyclohexane group, a cyclohexene group, or a benzene group.

[0548] The “fourth ring” as used herein may be a furan group, a thiophene group, a pyrrole group, a silole group, an oxazole group, an isoxazole group, an oxadiazole group, an isoxadiazole group, an oxatriazole group, an isoxatriazole group, a thiazole group, an isothiazole group, a thiadiazole group, an isothiadiazole group, a thiatriazole group, an isothiatriazole group, a pyrazole group, an imidazole group, a triazole group, a tetrazole group, an azasilole group, a diazasilole group, a triazasilole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, or a triazine group.

[0549] In one or more embodiments, the π electron-depleted nitrogen-containing C.sub.1-C.sub.60 cyclic group may be an imidazole group, a pyrazole group, a thiazole group, an isothiazole group, an oxazole group, an isoxazole group, a pyridine group, a pyrazine group, a pyridazine group, a pyrimidine group, an indazole group, a purine group, a quinoline group, an isoquinoline group, a benzoquinoline group, a benzoisoquinoline group, a phthalazine group, a naphthyridine group, a quinoxaline group, a benzoquinoxaline group, a quinazoline group, a cinnoline group, a phenanthridine group, an acridine group, a phenanthroline group, a phenazine group, a benzimidazole group, an isobenzothiazole group, a benzoxazole group, an isobenzoxazole group, a triazole group, a tetrazole group, an oxadiazole group, a triazine group, a thiadiazole group, an imidazopyridine group, an imidazopyrimidine group, an azacarbazole group, an azadibenzofuran group, an azadibenzothiophene group, an azadibenzosilole group, an acridine group, or a pyridopyrazine group.

[0550] In one or more embodiments, the π electron-rich C.sub.3-C.sub.60 cyclic group may be a benzene group, a heptalene group, an indene group, a naphthalene group, an azulene group, an indacene group, an acenaphthylene group, a fluorene group, a spiro-bifluorene group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pentacene group, a hexacene group, a pentaphene group, a rubicene group, a coronene group, an ovalene group, a pyrrole group, a furan group, a thiophene group, an isoindole group, an indole group, an indene group, a benzofuran group, a benzothiophene group, a benzosilole group, a naphthopyrrole group, a naphthofuran group, a naphthothiophene group, a naphthosilole group, a benzocarbazole group, a dibenzocarbazole group, a dibenzofuran group, a dibenzothiophene group, a carbazole group, a dibenzosilole group, an indenocarbazole group, an indolocarbazole group, a benzofurocarbazole group, a benzothienocarbazole group, a benzosilolocarbazole group, a triindolobenzene group, a pyrrolophenanthrene group, a furanophenanthrene group, a thienophenanthrene group, a benzonaphthofuran group, a benzonapthothiophene group, an (indolo)phenanthrene group, a (benzofurano)phenanthrene group, or a (benzothieno)phenanthrene group.

[0551] For example, the C.sub.5-C.sub.60 carbocyclic group may be a cyclopentane group, a cyclohexane group, a cyclohexene group, a benzene group, a naphthalene group, an anthracene group, a phenanthrene group, a triphenylene group, a pyrene group, a chrysene group, a 1,2,3,4-tetrahydronaphthalene group, cyclopentadiene group, an indene group, a fluorene group, a 5,6,7,8-tetrahydroisoquinoline group, a 5,6,7,8-tetrahydroquinoline group, an adamantane group, a norbornane group, or a norbornene group.

[0552] For example, the C.sub.1-C.sub.60 heterocyclic group may be a thiophene group, a furan group, a pyrrole group, a cyclopentadiene group, a silole group, a borole group, a phosphole group, a selenophene group, a germole group, a benzothiophene group, a benzofuran group, an indole group, an indene group, a benzosilole group, a benzoborole group, a benzophosphole group, a benzoselenophene group, a benzogermole group, a dibenzothiophene group, a dibenzofuran group, a carbazole group, a dibenzosilole group, a dibenzoborole group, a dibenzophosphole group, a dibenzoselenophene group, a dibenzogermole group, a dibenzothiophene 5-oxide group, a 9H-fluorene-9-one group, a dibenzothiophene 5,5-dioxide group, an azabenzothiophene group, an azabenzofuran group, an azaindole group, an azaindene group, an azabenzosilole group, an azabenzoborole group, an azabenzophosphole group, an azabenzoselenophene group, an azabenzogermole group, an azadibenzothiophene group, an azadibenzofuran group, an azacarbazole group, an azafluorene group, an azadibenzosilole group, an azadibenzoborole group, an azadibenzophosphole group, an azadibenzoselenophene group, an azadibenzogermole group, an azadibenzothiophene 5-oxide group, an aza-9H-fluorene-9-one group, an azadibenzothiophene 5,5-dioxide group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a quinoxaline group, a quinazoline group, a phenanthroline group, a pyrazole group, an imidazole group, a triazole group, an oxazole group, an isoxazole group, a thiazole group, an isothiazole group, an oxadiazole group, a thiadiazole group, a benzopyrazole group, a benzimidazole group, a benzoxazole group, a benzothiazole group, a benzoxadiazole group, or a benzothiadiazole group.

[0553] The term “a π electron-deficient nitrogen-containing C.sub.1-C.sub.60 cyclic group, a π electron-rich C.sub.3-C.sub.60 cyclic group, a C.sub.5-C.sub.60 cyclic group, and a C.sub.1-C.sub.60 heterocyclic group” may be part of a condensed cycle or may be a monovalent, a divalent, a trivalent, a tetravalent, a pentavalent, or a hexavalent group, depending on the formula structure.

[0554] As used herein, the number of carbons in each group that is substituted (e.g., C.sub.1-C.sub.60) excludes the number of carbons in the substituent. For example, a C.sub.1-C.sub.60 alkyl group can be substituted with a C.sub.1-C.sub.60 alkyl group. The total number of carbons included in the C.sub.1-C.sub.60 alkyl group substituted with the C.sub.1-C.sub.60 alkyl group is not limited to 60 carbons. In addition, more than one C.sub.1-C.sub.60 alkyl substituent may be present on the C.sub.1-C.sub.60 alkyl group. This definition is not limited to the C.sub.1-C.sub.60 alkyl group and applies to all substituted groups that recite a carbon range.

[0555] In the present specification, at least one substituent of the substituted C.sub.5-C.sub.30 carbocyclic group, the substituted C.sub.1-C.sub.30 heterocyclic group, the substituted C.sub.1-C.sub.60 alkyl group, the substituted C.sub.2-C.sub.60 alkenyl group, the substituted C.sub.2-C.sub.60 alkynyl group, the substituted C.sub.1-C.sub.60 alkoxy group, the substituted C.sub.3-C.sub.10 cycloalkyl group, the substituted C.sub.1-C.sub.10 heterocycloalkyl group, the substituted C.sub.3-C.sub.10 cycloalkenyl group, the substituted C.sub.2-C.sub.10 heterocycloalkenyl group, the substituted C.sub.6-C.sub.60 aryl group, the substituted C.sub.6-C.sub.60 aryloxy group, the substituted C.sub.6-C.sub.60 arylthio group, the substituted C.sub.1-C.sub.60 heteroaryl group, the substituted monovalent aromatic condensed polycyclic group, the substituted monovalent aromatic condensed heteropolycyclic group, the substituted monovalent non-aromatic condensed polycyclic group, and the substituted monovalent non-aromatic condensed heteropolycyclic group may be: [0556] deuterium, —F, —Cl, —Br, —I, —CD.sub.3, —CD.sub.2H, —CDH.sub.2, —CF.sub.3, —CF.sub.2H, —CFH.sub.2, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid or a salt thereof, a sulfonic acid or a salt thereof, a phosphoric acid or a salt thereof, a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, and a C.sub.1-C.sub.60 alkoxy group; [0557] a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, and a C.sub.1-C.sub.60 alkoxy group, each substituted with at least one deuterium, —F, —Cl, —Br, —I, —CD.sub.3, —CD.sub.2H, —CDH.sub.2, —CF.sub.3, —CF.sub.2H, —CFH.sub.2, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.2-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent aromatic condensed polycyclic group, a monovalent aromatic condensed heteropolycyclic group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q.sub.11)(Q.sub.12), —Si(Q.sub.13)(Q.sub.14)(Q.sub.15), —B(Q.sub.16)(Q.sub.17), —P(═O)(Q.sub.18)(Q.sub.19), or a combination thereof; [0558] a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.2-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent aromatic condensed polycyclic group, a monovalent aromatic condensed heteropolycyclic group, a monovalent non-aromatic condensed polycyclic group, or a monovalent non-aromatic condensed heteropolycyclic group; [0559] a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.2-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent aromatic condensed polycyclic group, a monovalent aromatic condensed heteropolycyclic group, a monovalent non-aromatic condensed polycyclic group, or a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one of deuterium, —F, —Cl, —Br, —I, —CD.sub.3, —CD.sub.2H, —CDH.sub.2, —CF.sub.3, —CF.sub.2H, —CFH.sub.2, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, a C.sub.1-C.sub.60 alkoxy group, a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.2-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent aromatic condensed polycyclic group, a monovalent aromatic condensed heteropolycyclic group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q.sub.21)(Q.sub.22), —Si(Q.sub.23)(Q.sub.24)(Q.sub.25), —B(Q.sub.26)(Q.sub.27), —P(═O)(Q.sub.28)(Q.sub.29), or a combination thereof; or [0560] —N(Q.sub.31)(Q.sub.32), —Si(Q.sub.33)(Q.sub.34)(Q.sub.35), —B(Q.sub.36)(Q.sub.37), or —P(═O)(Q.sub.38)(Q.sub.39), [0561] wherein Q.sub.1 to Q.sub.9, Q.sub.11 to Q.sub.19, Q.sub.21 to Q.sub.29, and Q.sub.31 to Q.sub.39 may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, a C.sub.1-C.sub.60 alkoxy group, a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.2-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryl group substituted with at least one a C.sub.1-C.sub.60 alkyl group and a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent aromatic condensed polycyclic group, a monovalent aromatic condensed heteropolycyclic group, a monovalent non-aromatic condensed polycyclic group, or a monovalent non-aromatic condensed heteropolycyclic group.

[0562] The term “room temperature” used herein refers to a temperature of about 25° C.

[0563] The terms “a biphenyl group, a terphenyl group, and a tetraphenyl group” used herein respectively refer to monovalent groups in which two, three, or four phenyl groups which are linked together via a single bond.

[0564] The terms “a cyano-containing phenyl group, a cyano-containing biphenyl group, a cyano-containing terphenyl group, and a cyano-containing tetraphenyl group” used herein respectively refer to a phenyl group, a biphenyl group, a terphenyl group, and a tetraphenyl group, each of which is substituted with at least one cyano group. In “a cyano-containing phenyl group, a cyano-containing biphenyl group, a cyano-containing terphenyl group, and a cyano-containing tetraphenyl group”, a cyano group may be substituted to any position of the corresponding group, and the “cyano-containing phenyl group, the cyano-containing biphenyl group, the cyano-containing terphenyl group, and the cyano-containing tetraphenyl group” may further include substituents other than a cyano group. For example, a phenyl group substituted with a cyano group, and a phenyl group substituted with a cyano group and a methyl group may all belong to “a cyano-containing phenyl group.”

[0565] Hereinafter, a compound and an organic light-emitting device according to embodiments are described in detail with reference to Synthesis Examples and Examples. However, the organic light-emitting device is not limited thereto. The wording ‘“B’ was used instead of ‘A″’ used in describing Synthesis Examples means that an amount of ‘A’ used was identical to an amount of ‘B’ used, in terms of a molar equivalent.

Examples

Synthesis Example 1: Synthesis of Compound 1

[0566] ##STR03229##

Synthesis of Intermediate 1(a)

[0567] 3,6-di-tert-butyl-9H-carbazole (20.0 g, 71.6 mmol) was dissolved in 40 ml of N,N-dimethylformamide (DMF) in a round-bottom flask, and the mixed solution was cooled and stirred at 0° C. Next, N-bromosuccinimide (26.1 g, 147 mmol) dissolved in 60 ml of DMF was slowly added dropwise thereto, and the reaction was carried out while stirring at room temperature. After completion of the reaction, 2 moles of an aqueous sodium thiosulfate solution were added to the reaction mixture, and an extraction process was performed thereon by using distilled water and dichloromethane (DCM). The aqueous solution layer was removed therefrom, and a resulting filtrate was concentrated under pressure. The product thus obtained was separated by column chromatography to obtain 28.2 g (yield of 90%) of Intermediate 1(a) which was a white solid.

[0568] LC-Mass (calculated: 280.21 g/mol, found: 281.21 (M+1)).

Synthesis of Intermediate 1(b)

[0569] Intermediate 1(a) (9.69 g, 22.2 mmol), diphenylamine (1.50 g, 8.86 mmol), tris(dibenzylideneacetone)dipalladium(0) (Pd.sub.2(dba).sub.3) (0.243 g, 0.266 mmol), X-Phos (0.254 g, 0.532 mmol), sodium tert-butoxide (NaOtBu) (1.70 g, 17.7 mmol), and 80 ml of toluene were added to a round flask, and the mixed solution was stirred at 150° C. After completion of the reaction, DCM was added to the reactor cooled to room temperature to dilute the solution, and then passed through a filter filled with silica gel for filtration under reduced pressure. A filtrate thus obtained was concentrated under reduced pressure, adsorbed on silica gel, and separated by silica gel column chromatography, to obtain 2.42 g (yield of 52%) Intermediate 1(b) which is a white solid.

[0570] LC-Mass (calculated: 525.19 g/mol, found: 526.09 (M+1)).

Synthesis of Intermediate 1(c)

[0571] Intermediate 1(b) (3.50 g, 6.66 mmol), bis(pinacolato)diboron (B.sub.2pin2) (2.54 g, 9.99 mmol), [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (PdCl.sub.2(dppf)) (0.487 g, 0.666 mmol), potassium acetate (KOAc) (3.68 g, 37.5 mmol), and 70 ml of 1,4-dioxane were added to a round flask and stirred under reflux at 120° C. in a nitrogen atmosphere. After completion of reaction, an organic solvent layer was concentrated and purified by column chromatography to obtain 1.11 g (yield of 68%) of Intermediate 1(c).

[0572] LC-Mass (calculated: 572.36 g/mol, found: 573.25 (M+1)).

Synthesis of Intermediate 1(d)

[0573] Intermediate 1(c) (2.50 g, 4.36 mmol) 1,4-dibromo-2,5-diiodobenzene (0.850 g, 1.74 mmol), tetrakis(triphenylphosphine)palladium(0) (Pd(PPh.sub.3).sub.4) (0.201 g, 0.174 mmol), S-Phos (0.143 g, 0.349 mmol), and 20 ml of 1,2-dimethoxyethane (1,2-DME) were added to a round flask and stirred. 10 ml of 4 moles of an aqueous potassium phosphate tribasic (K.sub.3PO.sub.4) solution (8.49 g, 40 mmol) was added to the reaction mixture, and the resulting mixed solution was heated and stirred at 80° C. After completion of the reaction, an extraction process was performed by using distilled water and dichloromethane on the mixed solution cooled to room temperature, and residual water was removed with anhydrous magnesium sulfate, and the resulting product was filtered under reduced pressure. An organic layer thus obtained was concentrated under reduced pressure, and a solid thus obtained was separated and purified through column chromatography to obtain 0.976 g (yield of 50%) of Intermediate 1(d).

[0574] LC-Mass (calculated: 1123.39 g/mol, found: 1124.00 (M+1)).

Synthesis of Compound 1

[0575] Intermediate 1(d) (0.13 g, 0.12 mmol), copper(I) iodide (CuI) (0.022 g, 0.12 mmol), 1,10-phenanthroline (0.021 g, 0.12 mmol), phosphate potassium (0.098 g, 0.46 mmol), and 5 ml of DMF were heated and stirred at 100° C. After completion of the reaction, DCM was added to the reactor cooled to room temperature to dilute the solution, and then passed through a filter filled with silica gel for filtration under reduced pressure. A filtrate thus obtained was concentrated under reduced pressure, adsorbed on silica gel, and separated by silica gel column chromatography. DCM and methanol (MeOH) were used to filter the precipitate, and a solid thus obtained was dried in a vacuum oven to obtain 0.076 g (yield of 69%) of Compound 1 which was a yellow solid.

[0576] LC-Mass (calculated: 963.5366 g/mol, found: 964.5367 (M+1)).

Synthesis Example 2: Synthesis of Compound 2

[0577] ##STR03230##

Synthesis of Intermediate 2(a)

[0578] Intermediate 1(a) (11.7 g, 26.8 mmol), (9-phenyl-9H-carbazol-3-yl)boronic acid) (5.12 g, 17.8 mmol), Pd(PPh.sub.3).sub.4 (0.618 g, 0.178 mmol), and 100 ml of tetrahydrofuran (THF) were added to a round flask and stirred. 50 ml of 2 moles of an aqueous potassium carbonate (K.sub.2CO.sub.3) (13.8 g, 100 mmol) solution was added thereto and stirred under reflux at 140° C. After completion of the reaction, DCM was added to the reactor cooled to room temperature to dilute the solution, and then passed through a filter filled with silica gel for filtration under reduced pressure. A filtrate thus obtained was concentrated under reduced pressure, adsorbed on silica gel, and separated by silica gel column chromatography. DCM and methanol (MeOH) were used to filter the precipitate, and a solid thus obtained was dried in a vacuum oven to obtain 6.12 g (yield of 57%) of Intermediate 2(a) which was a white solid.

[0579] LC-Mass (calculated: 599.21 g/mol, found: 600.11 (M+1)).

Synthesis of Intermediate 2(b)

[0580] Intermediate 2(b) (14.6 g, yield of 87%) was obtained in the same manner as used to prepare Intermediate 1(c) in Synthesis Example 1, except that Intermediate 2(a) (15.5 g, 25.9 mmol) was used instead of Intermediate 1(b).

[0581] LC-Mass (calculated: 647.38 g/mol, found: 648.25 (M+1)).

Synthesis of Intermediate 2(c)

[0582] Intermediate 2(c) (0.981 g, yield of 38%) was obtained in the same manner as used to prepare Intermediate 1(d) in Synthesis Example 1, except that Intermediate 2(b) (3.32 g, 5.13 mmol) was used instead of Intermediate 1(c).

[0583] LC-Mass (calculated: 1271.42 g/mol, found: 1272.12 (M+1)).

Synthesis of Compound 2

[0584] Compound 2 (0.766 g, yield of 88%) was obtained in the same manner as used to prepare Compound 1 in Synthesis Example 11, except that Intermediate 2(c) (1.00 g, 0.785 mmol) was used instead of Intermediate 1(d).

[0585] LC-Mass (calculated: 1111.5679 g/mol, found: 1112.5677 (M+1)).

Synthesis Example 3: Synthesis of Compound 3

[0586] ##STR03231##

Synthesis of Intermediate 3(a)

[0587] 2,6-dibromonaphthalene-1,5-diol (5.00 g, 15.7 mmol) and pyridine (7.60 ml, 94.4 mmol) were dissolved in 60 ml of DCM, and the mixed solution was cooled at stirred at 0° C. for 30 minutes. Trifluoromethanesulfonic anhydride (7.94 ml, 47.2 mmol) was slowly added dropwise to the mixed solution, and a reaction was carried out while stirring at room temperature for 8 hours. An extraction process was performed by using distilled water and dichloromethane on the mixed solution cooled to room temperature, and residual water was removed with anhydrous magnesium sulfate, and the resulting product was filtered under reduced pressure. An organic layer thus obtained was concentrated under reduced pressure, and a solid thus obtained was separated and purified through column chromatography to obtain 5.68 g (yield of 62%) of Intermediate 3(a).

[0588] LC-Mass (calculated: 580.78 g/mol, found: 581.80 (M+1)).

Synthesis of Intermediate 3(b)

[0589] Intermediate 3(b) (2.93 g, yield 29%) was synthesized in the same manner as used to prepare Intermediate 1(d) in Synthesis Example 1, except that Intermediate 3(a) (5.00 g, 8.59 mmol) was used instead of 1,4-dibromo-2,5-diiodobenzene.

[0590] LC-Mass (calculated: 1173.40 g/mol, found: 1174.41 (M+1)).

Synthesis of Compound 3

[0591] Compound 3 (1.52 g, yield of 88%) was obtained in the same manner as used to prepare Compound 1 in Synthesis Example 11, except that Intermediate 3(b) (2.00 g, 1.70 mmol) was used instead of Intermediate 1(d).

[0592] LC-Mass (calculated: 1013.5522 g/mol, found: 1014.5522 (M+1)).

Synthesis Example 4: Synthesis of Compound 4

[0593] ##STR03232##

Intermediate 4(a)

[0594] Intermediate 4(a) (4.26 g, yield 25%) was synthesized in the same manner as used to prepare Intermediate 2(c) in Synthesis Example 2, except that Intermediate 3(a) (7.50 g, 12.9 mmol) was used instead of 1,4-dibromo-2,5-diiodobenzene.

[0595] LC-Mass (calculated: 1321.44 g/mol, found: 1322.46 (M+1)).

Synthesis of Compound 4

[0596] Compound 4 (2.21 g, yield of 84%) was obtained in the same manner as used to prepare Compound 2 in Synthesis Example 2, except that Intermediate 4(a) (3.00 g, 2.27 mmol) was used instead of Intermediate 2(c).

[0597] LC-Mass (calculated: 1161.5835 g/mol, found: 1162.5835 (M+1)).

Synthesis Example 5: Synthesis of Compound 5

[0598] ##STR03233##

Synthesis of Intermediate 5(a)

[0599] Intermediate 5(a) (6.13 g, yield 67%) was obtained in the same manner as used to prepare Intermediate 3(a) in Synthesis Example 3, except that 1,5-dibromonaphthalene-2,6-diol (5.00 g, 15.7 mmol) was used instead of 2,6-dibromonaphthalene-1,5-diol.

[0600] LC-Mass (calculated: 580.78 g/mol, found: 581.78 (M+1)).

Synthesis of Intermediate 5(b)

[0601] Intermediate 5(b) (3.43 g, yield 34%) was synthesized in the same manner as used to prepare Intermediate 1(d) in Synthesis Example 1, except that Intermediate 5(a) (7.00 g, 8.59 mmol) was used instead of 1,4-dibromo-2,5-diiodobenzene.

[0602] LC-Mass (calculated: 1173.40 g/mol, found: 1174.40 (M+1)).

Synthesis of Compound 5

[0603] Compound 5 (2.40 g, yield of 81%) was obtained in the same manner as used to prepare Compound 1 in Synthesis Example 11, except that Intermediate 5(b) (3.00 g, 2.55 mmol) was used instead of Intermediate 1(d).

[0604] LC-Mass (calculated: 1013.5522 g/mol, found: 1014.5522 (M+1)).

Synthesis Example 6: Synthesis of Compound 6

[0605] ##STR03234##

Synthesis of Intermediate 6(a)

[0606] Intermediate 6(a) (4.62 g, yield 29%) was synthesized in the same manner as used to prepare Intermediate 3(a) in Synthesis Example 3, except that Intermediate 5(a) (7.00 g, 12.0 mmol) was used instead of 1,4-dibromo-2,5-diiodobenzene.

[0607] LC-Mass (calculated: 1321.44 g/mol, found: 1322.45 (M+1)).

Synthesis of Compound 6

[0608] Compound 6 (3.17 g, yield of 86%) was obtained in the same manner as used to prepare Compound 1 in Synthesis Example 11, except that Intermediate 6(a) (4.20 g, 3.17 mmol) was used instead of Intermediate 1(d).

[0609] LC-Mass (calculated: 1161.5835 g/mol, found: 1162.5835 (M+1)).

Evaluation Example 1: Evaluation of HOMO, LUMO, T.SUB.1., and S.SUB.1 .Energy Levels

[0610] For the compounds of Table 8, the HOMO, LUMO, Ti, and Si energy levels were measured according to methods described in Table 7, and results thereof are shown in Table 8:

TABLE-US-00007 TABLE 7 HOMO By using cyclic voltammetry (CV) (electrolyte: 0.1M energy TBAP/solvent: ACN/electrode: 3-electrode system (working level electrode: Pt wire, reference electrode: Ag/AgCl, and auxiliary evaluation electrode: Pt wire)), the potential (V)-current (A) graph method of each compound was obtained, and then, from the oxidation onset of the graph, the HOMO energy level of each compound was calculated. LUMO Each compound was diluted in THF to a concentration of energy 1 × 10.sup.−5 M, and the UV absorption spectrum thereof was level measured at room temperature by using a JASCO V-730 UV evaluation spectrometer. Then, the lowest unoccupied molecular orbital method (LUMO) energy level was calculated by using the optical band gap (Eg) from the edge of the absorption spectrum and HOMO energy level. T.sub.1 energy Each compound was dissolved in THF to a method concentration of 1 × 10.sup.−5 M, and then placed in a quartz level cell to lower the temperature by using liquid nitrogen (77 K). evaluation Afterwards, a photoluminescence spectrum was measured with a delay time of 1 millisecond by using a fluorescence spectrometer (PerkinElmer, LS-55). S.sub.1 energy S.sub.1 energy level was measured similarly to the T.sub.1 energy level level evaluation method, except that it was measured without evaluation delay time. Here, S.sub.1 was determined as a maximum emission method peak point.

TABLE-US-00008 TABLE 8 HOMO LUMO S1 T1 ΔE.sub.ST Compound No. (eV) (eV) (eV) (eV) (eV) 1 (tBisICz-DPA) −5.65 −2.89 2.79 2.51 0.28 2 (tBisICz-PhCz) −5.67 −2.89 2.82 2.51 0.31 A — — 2.84 2.55 0.29 B −5.56 −2.93 2.68 2.32 0.36 C −5.62 −2.89 2.67 2.31 0.36

##STR03235## ##STR03236##

[0611] Referring to Table 8, it was confirmed that Compounds 1 and 2 each had such electric characteristics that are suitable for use as a dopant for an electronic device, for example, an organic light-emitting device.

Evaluation Example 2: Measurement of Photoluminescence (PL) of Solution

[0612] The resulting Compounds and the Comparative Compound were each dissolved in toluene to prepare a 1×10.sup.−5 M solution. This solution was filled in a 1 cm square four-sided transmission cell, and PL measurement was performed at room temperature using a spectrofluorometer F7000 (available from Hitachi High-Technologies Corporation). A peak wavelength, a FWHM, and a Stokes shift were computed from the obtained emission spectrum. The results of evaluation are shown in Table 10.

TABLE-US-00009 TABLE 9 Peak wavelength Stocks shift FWHM Compound No. (nm) (nm) (nm) 1 (tBisICz-DPA) 444 17 27 2 (tBisICz-PhCz) 440 12 16 A 436 11 22 B 475 22 29 C 476 24 30

[0613] Referring to Table 8, it was confirmed that Compounds 1 and 2 each had improved color characteristics.

Example 1-1

[0614] An ITO glass substrate was cut to a size of 50 mm×50 mm×0.5 mm and then, sonicated in acetone isopropyl alcohol and pure water, each for 15 minutes, and then, washed by exposure to ultraviolet (UV) light ozone for 30 minutes.

[0615] Subsequently, PEDOT:PSS was spin-coated on the ITO electrode (anode) of the glass substrate to form a first hole injection layer having a thickness of 40 nm, TAPC was deposited on the hole injection layer to form a second hole injection layer having a thickness of 5 nm, TCTA was deposited on the second hole injection layer to form a first hole transport layer having a thickness of 5 nm, PCzAc was deposited on the first hole transport layer to form a second hole transport layer having a thickness of 5 nm, and mCP was deposited on the second hole transport layer to form an electron blocking layer having a thickness of 5 nm, thereby forming a hole transport region.

[0616] In the hole transport region, mCP (first host), TSPO1 (second host), and Compound 1(dopant) (In this regard, a content of the dopant was about 3 wt % based on the total weight of the first host, the second host, and the dopant) were co-deposited to form an emission layer having a thickness of 25 nm.

[0617] TSPO1 was deposited on the emission layer to form an electron transport layer having a thickness of 25 nm, LiF was deposited on the electron transport layer to form an electron injection layer having a thickness of 1.5 nm, and Al was formed on the electron injection layer to a thickness of 200 nm, thereby completing the manufacture of an organic light-emitting device.

##STR03237## ##STR03238##

Examples 1-2 to 1-6 and Comparative Examples 1-1 to 1-3

[0618] An organic light-emitting device was manufactured in the same manner as in Example 1-1, except that, for use as a dopant in forming an emission layer, corresponding compounds shown in Table 10 were used.

Example 2-1

[0619] An ITO glass substrate was cut to a size of 50 mm×50 mm×0.5 mm and then, sonicated in acetone isopropyl alcohol and pure water, each for 15 minutes, and then, washed by exposure to ultraviolet (UV) light ozone for 30 minutes.

[0620] Subsequently, PEDOT:PSS was spin-coated on the ITO electrode (anode) of the glass substrate to form a hole injection layer having a thickness of 90 nm, TAPC was deposited on the hole injection layer to form a hole transport layer having a thickness of 20 nm, and mCP was deposited on the hole transport layer to form an electron blocking layer having a thickness of 10 nm.

[0621] On the hole transport region, mCP (first host), TSPO1 (second host), Pt* (sensitizer), and Compound 1 (dopant) (in this regard, a content of the dopant was about 0.4 wt % based on the total weight of the host, the sensitizer, and the dopant, and a content of the sensitizer was about 13 wt % based on the total weight of the host, the sensitizer, and the dopant) were co-deposited to form an emission layer having a thickness of 25 nm.

[0622] TSPO1 was deposited on the emission layer to form a first electron transport layer having a thickness of 5 nm, TPBi was deposited on the first electron transport layer to form a second electron transport layer having a thickness of 20 nm, LiF was deposited on the second electron transport layer to form an electron injection layer having a thickness of 1.5 nm, and Al was formed on the electron injection layer to a thickness of 200 nm, thereby completing the manufacture of an organic light-emitting device.

##STR03239## ##STR03240##

Examples 2-2 to 2-6 and Comparative Examples 2-1 to 2-3

[0623] An organic light-emitting device was manufactured in the same manner as in Example 2-1, except that, for use as a dopant in forming an emission layer, corresponding compounds shown in Table 11 were used.

Evaluation Example: Evaluation of OLED Characteristics

[0624] For the organic light-emitting devices prepared according to Examples and Comparative Examples above, the driving voltage, maximum emission wavelength, CIE y color coordinates (at 1000 nit), FWHM, and relative efficiency were measured by using a current-voltage meter (Keithley 2400) and a luminance meter (Minolta Cs-1000A), and results thereof are summarized in Tables 10 and 11.

TABLE-US-00010 TABLE 10 Weight Weight ratio of ratio of Doping Driving Relative first second concentration voltage λ.sub.EL FWHM efficiency host host Dopant (wt %) (V) (nm) (nm) CIE y (%) Example 1-1 50 50 1 3 6.5 452 28 0.05 110 Example 1-2 50 50 2 3 6.2 446 19 0.04 134 Comparative 50 50 A 3 5.7 448 35 0.07 100 Example 1-1 Comparative 50 50 B 3 6.5 477 44 >0.2 105 Example 1-2 Comparative 50 50 C 3 7.4 480 46 >0.2 81 Example 1-3

TABLE-US-00011 TABLE 11 Weight Weight ratio of ratio of Concentration Doping Driving Relative first second of sensitizer concentration voltage λ.sub.EL efficiency host host Sensitizer (wt %) Dopant (wt %) (V) (nm) (%) Example 2-1 50 50 Pt* 13 1 0.4 4.09 462 142 Example 2-4 50 50 Pt* 13 2 0.4 3.99 462 137 Comparative 50 50 Pt* 13 A 0.4 4.35 466 100 Example 2-1 Comparative 50 50 Pt* 13 B 0.4 4.07 479 106 Example 2-2

[0625] Referring to Tables 10 and 11, it was confirmed that the organic light-emitting device of Examples had high efficiency compared to the organic light-emitting devices of Comparative Examples.

[0626] According to the one or more embodiments, an organic light-emitting device including a heterocyclic compound may have improved efficiency and/or colorimetric purity.

[0627] It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments. While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims.