Patent Publication Number: US-10319919-B2

Title: Compound and organic light-emitting device including the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to and the benefit of Korean Patent Application No. 10-2015-0144316, filed on Oct. 15, 2015, in the Korean Intellectual Property Office, the entire content of which is incorporated herein by reference. 
     BACKGROUND 
     1. Field 
     One or more aspects of embodiments of the present disclosure relate to a compound and an organic light-emitting device including the same. 
     2. Description of the Related Art 
     Organic light-emitting devices are self-emission devices that have wide viewing angles, high contrast ratios, short response times, and excellent brightness, driving voltage, and/or response speed characteristics, and can produce full-color images. An organic light-emitting device may include a first electrode disposed (e.g., positioned) on a substrate, and a hole transport region, an emission layer, an electron transport region, and a second electrode, which are sequentially disposed on the first electrode. Holes provided from the first electrode, for example, may move toward the emission layer through the hole transport region, and electrons provided from the second electrode, for example, may move toward the emission layer through the electron transport region. Carriers, such as the holes and electrons, can then recombine in the emission layer to produce excitons. These excitons transition from an excited state to a ground state, thereby generating light. 
     SUMMARY 
     One or more aspects of example embodiments of the present disclosure are directed toward compounds that have excellent electron transport capability and material stability and that are suitable for use as an electron injection material or electron transport material. 
     One or more aspects of example embodiments are directed toward organic light-emitting devices that have high efficiency, low voltage, high luminance, and long lifespan, due to the inclusion of the compounds according to embodiments of the present disclosure. 
     Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments. 
     According to one or more example embodiments, a compound represented by Formula 1 is provided: 
     
       
         
         
             
             
         
       
     
     In Formula 1, 
     A 1  to A 8  may each independently be selected from CR 11 , CR 12 , CR 13 , CR 14 , CR 15 , CR 16 , CR 17 , CR 18 , and N; where at least one of A 1  to A 8  is N; 
     R 1 , R 2 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , and R 18  may each independently be selected from hydrogen, deuterium, a halogen group, a nitro group, a cyano group, a substituted or unsubstituted C 1 -C 60  alkyl group, a substituted or unsubstituted C 2 -C 60  alkenyl group, a substituted or unsubstituted C 2 -C 60  alkynyl group, a substituted or unsubstituted C 1 -C 60  alkoxy group, a substituted or unsubstituted C 3 -C 10  cycloalkyl group, a substituted or unsubstituted C 2 -C 10  heterocycloalkyl group, a substituted or unsubstituted C 3 -C 10  cycloalkenyl group, a substituted or unsubstituted C 2 -C 10  heterocycloalkenyl group, a substituted or unsubstituted C 6 -C 60  aryl group, a substituted or unsubstituted C 6 -C 60  aryloxy group, a substituted or unsubstituted C 6 -C 60  arylthio group, a substituted or unsubstituted C 1 -C 60  heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, P(═O)R 31 R 32 , P(═S)R 33 R 34 , S(═O) 2 R 35 , and S(═O)R 36 ; 
     R 31 , R 32 , R 33 , R 34 , R 35 , and R 36  may each independently be selected from hydrogen, deuterium, a halogen group, a nitro group, a cyano group, a substituted or unsubstituted C 1 -C 60  alkyl group, a substituted or unsubstituted C 6 -C 60  aryl group, a substituted or unsubstituted C 1 -C 60  heteroaryl group, and a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group; 
     L 1  and L 2  may each independently be selected from a substituted or unsubstituted C 6 -C 60  arylene group, a substituted or unsubstituted C 1 -C 60  heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group; 
     a1 and a2 may be each independently an integer selected from 0 to 3; 
     m and n may each independently be an integer selected from 1 to 2; and 
     at least one substituent of the substituted C 1 -C 60  alkyl group, substituted C 2 -C 60  alkenyl group, substituted C 2 -C 60  alkynyl group, substituted C 1 -C 60  alkoxy group, substituted C 3 -C 10  cycloalkyl group, substituted C 2 -C 10  heterocycloalkyl group, substituted C 3 -C 10  cycloalkenyl group, substituted C 2 -C 10  heterocycloalkenyl group, substituted C 6 -C 60  aryl group, substituted C 6 -C 60  aryloxy group, substituted C 6 -C 60  arylthio group, substituted C 1 -C 60  heteroaryl group, substituted monovalent non-aromatic condensed polycyclic group, substituted monovalent non-aromatic condensed heteropolycyclic group, substituted C 6 -C 60  arylene group, substituted C 1 -C 60  heteroarylene group, a substituted divalent non-aromatic condensed polycyclic group, and a substituted divalent non-aromatic condensed heteropolycyclic group may be selected from the group consisting of: 
     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 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 2 -C 60  alkynyl group, and a C 1 -C 60  alkoxy group; 
     a C 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 2 -C 60  alkynyl group, and a C 1 -C 60  alkoxy group, each substituted with at least one selected from 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 3 -C 10  cycloalkyl group, a C 2 -C 10  heterocycloalkyl group, a C 3 -C 10  cycloalkenyl group, a C 2 -C 10  heterocycloalkenyl group, a C 6 -C 60  aryl group, a C 6 -C 60  aryloxy group, a C 6 -C 60  arylthio group, a C 1 -C 60  heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q 11 )(Q 12 ), —Si(Q 13 )(Q 14 )(Q 15 ), and —B(Q 16 )(Q 17 ); 
     a C 3 -C 10  cycloalkyl group, a C 2 -C 10  heterocycloalkyl group, a C 3 -C 10  cycloalkenyl group, a C 2 -C 10  heterocycloalkenyl group, a C 6 -C 60  aryl group, a C 6 -C 60  aryloxy group, a C 6 -C 60  arylthio group, a C 1 -C 60  heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group; and 
     a C 3 -C 10  cycloalkyl group, a C 2 -C 10  heterocycloalkyl group, a C 3 -C 10  cycloalkenyl group, a C 2 -C 10  heterocycloalkenyl group, a C 6 -C 60  aryl group, a C 6 -C 60  aryloxy group, a C 6 -C 60  arylthio group, a C 1 -C 60  heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from 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 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 2 -C 60  alkynyl group, a C 1 -C 60  alkoxy group, a C 3 -C 10  cycloalkyl group, a C 2 -C 10  heterocycloalkyl group, a C 3 -C 10  cycloalkenyl group, a C 2 -C 10  heterocycloalkenyl group, a C 6 -C 60  aryl group, a C 6 -C 60  aryloxy group, a C 6 -C 60  arylthio group, a C 1 -C 60  heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q 21 )(Q 22 ), —Si(Q 23 )(Q 24 )(Q 25 ), and —B(Q 26 )(Q 27 ), 
     wherein Q 11  to Q 17  and Q 21  to Q 27  may be each independently selected from 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 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 2 -C 60  alkynyl group, a C 1 -C 60  alkoxy group, a C 3 -C 10  cycloalkyl group, a C 2 -C 10  heterocycloalkyl group, a C 3 -C 10  cycloalkenyl group, a C 2 -C 10  heterocycloalkenyl group, a C 6 -C 60  aryl group, a C 1 -C 60  heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group. 
     According to one or more example embodiments, an organic light-emitting device includes: a first electrode; a second electrode facing the first electrode; and an organic layer between the first electrode and the second electrode, the organic layer including an emission layer, wherein the organic layer includes the compound according to embodiments of the present disclosure described above. 
     According to one or more example embodiments, a flat panel display apparatus includes the organic light-emitting device according to embodiments of the present disclosure, wherein the first electrode of the organic light-emitting device is electrically connected (e.g., coupled) to a source electrode or a drain electrode of a thin film transistor. 
     BRIEF DESCRIPTION OF THE DRAWING 
     These and/or other aspects will become apparent and more readily appreciated from the following description of the example embodiments, taken in conjunction with the drawing, which is a schematic view of an organic light-emitting device according to an embodiment of the present disclosure. 
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in more detail to example embodiments, examples of which are illustrated in the accompanying drawing, wherein like reference numerals refer to like elements throughout. In this regard, the present example embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the example embodiments are merely described below, by referring to the drawing, to explain aspects of the present description. 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,” “one of,” and “selected from,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. Further, the use of “may” when describing embodiments of the present invention refers to one or more embodiments of the present invention.” 
     An aspect of embodiments of the present disclosure provides a compound represented by Formula 1: 
     
       
         
         
             
             
         
       
     
     In Formula 1, 
     A 1  to A 8  may each independently be selected from CR 11 , CR 12 , CR 13 , CR 14 , CR 15 , CR 16 , CR 17 , CR 18 , and N; 
     where at least one of A 1  to A 8  is N; 
     R 1 , R 2 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , and R 18  may each independently be selected from hydrogen, deuterium, a halogen group, a nitro group, a cyano group, a substituted or unsubstituted C 1 -C 60  alkyl group, a substituted or unsubstituted C 2 -C 60  alkenyl group, a substituted or unsubstituted C 2 -C 60  alkynyl group, a substituted or unsubstituted C 1 -C 60  alkoxy group, a substituted or unsubstituted C 3 -C 10  cycloalkyl group, a substituted or unsubstituted C 2 -C 10  heterocycloalkyl group, a substituted or unsubstituted C 3 -C 10  cycloalkenyl group, a substituted or unsubstituted C 2 -C 10  heterocycloalkenyl group, a substituted or unsubstituted C 6 -C 60  aryl group, a substituted or unsubstituted C 6 -C 60  aryloxy group, a substituted or unsubstituted C 6 -C 60  arylthio group, a substituted or unsubstituted C 1 -C 60  heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, P(═O)R 31 R 32 , P(═S)R 33 R 34 , S(═O) 2 R 35 , and S(═O)R 36 ; 
     R 31 , R 32 , R 33 , R 34 , R 35 , and R 36  may each independently be selected from hydrogen, deuterium, a halogen group, a nitro group, a cyano group, a substituted or unsubstituted C 1 -C 60  alkyl group, a substituted or unsubstituted C 6 -C 60  aryl group, a substituted or unsubstituted C 1 -C 60  heteroaryl group, and a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group; 
     L 1  and L 2  may each independently be selected from a substituted or unsubstituted C 6 -C 60  arylene group, a substituted or unsubstituted C 1 -C 60  heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group; 
     a1 and a2 may each independently be an integer selected from 0 to 3; 
     m and n may each independently be an integer selected from 1 to 2; and 
     at least one substituent of the substituted C 1 -C 60  alkyl group, substituted C 2 -C 60  alkenyl group, substituted C 2 -C 60  alkynyl group, substituted C 1 -C 60  alkoxy group, substituted C 3 -C 10  cycloalkyl group, substituted C 2 -C 10  heterocycloalkyl group, substituted C 3 -C 10  cycloalkenyl group, substituted C 2 -C 10  heterocycloalkenyl group, substituted C 6 -C 60  aryl group, substituted C 6 -C 60  aryloxy group, substituted C 6 -C 60  arylthio group, substituted C 1 -C 60  heteroaryl group, substituted monovalent non-aromatic condensed polycyclic group, substituted monovalent non-aromatic condensed heteropolycyclic group, substituted C 6 -C 60  arylene group, substituted C 1 -C 60  heteroarylene group, a substituted divalent non-aromatic condensed polycyclic group, and a substituted divalent non-aromatic condensed heteropolycyclic group may be selected from the group consisting of: 
     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 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 2 -C 60  alkynyl group, and a C 1 -C 60  alkoxy group; 
     a C 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 2 -C 60  alkynyl group, and a C 1 -C 60  alkoxy group, each substituted with at least one selected from 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 3 -C 10  cycloalkyl group, a C 2 -C 10  heterocycloalkyl group, a C 3 -C 10  cycloalkenyl group, a C 2 -C 10  heterocycloalkenyl group, a C 6 -C 60  aryl group, a C 6 -C 60  aryloxy group, a C 6 -C 60  arylthio group, a C 1 -C 60  heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q 11 )(Q 12 ), —Si(Q 13 )(Q 14 )(Q 15 ), and —B(Q 16 )(Q 17 ); 
     a C 3 -C 10  cycloalkyl group, a C 2 -C 10  heterocycloalkyl group, a C 3 -C 10  cycloalkenyl group, a C 2 -C 10  heterocycloalkenyl group, a C 6 -C 60  aryl group, a C 6 -C 60  aryloxy group, a C 6 -C 60  arylthio group, a C 1 -C 60  heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group; and 
     a C 3 -C 10  cycloalkyl group, a C 2 -C 10  heterocycloalkyl group, a C 3 -C 10  cycloalkenyl group, a C 2 -C 10  heterocycloalkenyl group, a C 6 -C 60  aryl group, a C 6 -C 60  aryloxy group, a C 6 -C 60  arylthio group, a C 1 -C 60  heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from 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 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 2 -C 60  alkynyl group, a C 1 -C 60  alkoxy group, a C 3 -C 10  cycloalkyl group, a C 2 -C 10  heterocycloalkyl group, a C 3 -C 10  cycloalkenyl group, a C 2 -C 10  heterocycloalkenyl group, a C 6 -C 60  aryl group, a C 6 -C 60  aryloxy group, a C 6 -C 60  arylthio group, a C 1 -C 60  heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q 21 )(Q 22 ), —Si(Q 23 )(Q 24 )(Q 25 ), and —B(Q 26 )(Q 27 ), 
     wherein Q 11  to Q 17  and Q 21  to Q 27  may be each independently selected from 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 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 2 -C 60  alkynyl group, a C 1 -C 60  alkoxy group, a C 3 -C 10  cycloalkyl group, a C 2 -C 10  heterocycloalkyl group, a C 3 -C 10  cycloalkenyl group, a C 2 -C 10  heterocycloalkenyl group, a C 6 -C 60  aryl group, a C 1 -C 60  heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group. 
     Organometallic complexes including organic single molecular material(s) having relatively high stability to electrons and relatively high electron mobility may be used as an electron transport material. For example, Alq 3  has been described as having high stability and high electron affinity. However, when Alq 3  is used in a blue emission device, color purity may be decreased due to emission caused by exciton diffusion. 
     Also, flavon derivatives, germanium, and siliconchloropentadiene derivatives have been described. For example, the organic single molecular material may include PBD (2-biphenyl-4-yl-5-(4-t-butylphenyl)-1,3,4-oxadiazole)derivatives binding to a spiro compound and/or TPBI (2,2′,2″-(benzene-1,3,5-triyl)-tris(1-phenyl-1H-benzimidazole) having a hole blocking capability and excellent electron transport capability. For example, benzoimidazole derivatives have been described as having excellent durability. 
     However, an organic light-emitting device including an electron transport layer using the organic single molecular material may have a short luminescent lifespan, and low preservation durability and reliability. These problems occur at least in part due to separation or chemical change of an organic material, photochemical or electrochemical change of an organic material, and/or oxidation, exfoliation, and low durability of a cathode. 
     The compound of Formula 1 according to an embodiment of the present disclosure may be used as an electron transport material for an organic light-emitting device. The compound of Formula 1 may have high glass transition temperature (Tg) and a high melting point. Accordingly, during emission, heat resistance to Joule&#39;s heat occurring in an organic layer, between layers constituting the organic layer region, and/or between an organic layer and a metal electrode, and resistance to high-temperature conditions can be achieved. 
     An organic light-emitting device manufactured using the compound of Formula 1 according to an embodiment may have high durability during preservation and driving, and, since the compound of Formula 1 includes a heteroatom, characteristics of the organic light-emitting device may be improved. 
     In various embodiments, R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , and R 18  in Formula 1 may each independently be hydrogen or deuterium. 
     In various embodiments, R 31 , R 32 , R 33 , R 34 , R 35 , and R 36  may each independently be a substituted or unsubstituted C 6 -C 60  aryl group. 
     In various embodiments, L 1  and L 2  in Formula 1 may be each independently any one of Formulae 2a to 2d: 
     
       
         
         
             
             
         
       
     
     In Formulae 2a to 2d, * indicates a binding site. 
     In various embodiments, R 1  and R 2  in Formula 1 may be each independently selected from hydrogen, deuterium, a cyano group, P(═O)R 31 R 32 , P(═S)R 33 R 34 , and a group represented by one of Formulae 3a to 3k: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     In Formulae 3a to 3k, H 1  may be CR 41 R 42 , NR 43 , O, or S, 
     R 41  to R 43 , Z 1 , and Z 2  may be each independently selected from hydrogen, deuterium, a halogen group, a cyano group, a nitro group, a hydroxyl group, a carboxy group, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C6 to 20 aryl group, a substituted or unsubstituted C1 to C20 heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group; 
     p in Formulae 3a and 3k may be an integer selected from 1 to 4, p in Formula 3c may be an integer selected from 1 to 3, p in Formula 3d may be an integer selected from 1 to 9, p in Formulae 3e and 3g may be an integer selected from 1 to 6, p in Formula 3f may be an integer selected from 1 to 5, and p in Formulae 3h, 3i, and 3j may be an integer selected from 1 to 7, where when p is two or more, two or more Z 1 (s) may be identical to or different from each other; and 
     * indicates a binding site. 
     In various embodiments, the compound of Formula 1 may be represented by one of Formulae 2 to 5: 
     
       
         
         
             
             
         
       
     
     The definitions of substituents and symbols of Formulae 2 to 5 may be the same as described above. 
     In various embodiments, the compound of Formula 1 may be any one of Compounds 1 to 113 and 124 to 127, but is not limited thereto: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     The term “organic layer” used herein may refer to a single layer and/or a plurality of layers disposed (e.g., positioned) between the first electrode and the second electrode of an organic light-emitting device. A material included in the “organic layer” is not limited to an organic material. 
     The drawing is a schematic view of an organic light-emitting device  10  according to an embodiment of the present disclosure. The organic light-emitting device  10  includes a first electrode  110 , an organic layer  150 , and a second electrode  190 . 
     Hereinafter, the structure of an organic light-emitting device according to an embodiment and a method of manufacturing an organic light-emitting device according to an embodiment will be described in connection with the drawing. 
     In the drawing, a substrate may be additionally disposed (e.g., positioned) under the first electrode  110  or above the second electrode  190 . The substrate may be a glass substrate and/or a transparent plastic substrate, each having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and/or water-resistance. 
     The first electrode  110  may be formed by depositing or sputtering a material for forming the first electrode  110  on the substrate. When the first electrode  110  is an anode, the material for forming the first electrode  110  may be selected from materials with a high work function so as to facilitate hole injection. The first electrode  110  may be a reflective electrode, a semi-transmissive electrode, or a transmissive electrode. The material for the first electrode  110  may be a transparent and/or highly conductive material, and non-limiting examples of such material include indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO 2 ), and zinc oxide (ZnO). When the first electrode  110  is a semi-transmissive electrode or a reflective electrode, at least one selected from magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), and magnesium-silver (Mg—Ag) may be used as a material for forming the first electrode  110 . 
     The first electrode  110  may have a single-layer structure, or a multi-layer structure including two or more layers. For example, the first electrode  110  may have a three-layered structure of ITO/Ag/ITO, but the structure of the first electrode  110  is not limited thereto. 
     The organic layer  150  may be disposed on the first electrode  110 . The organic layer  150  may include an emission layer. 
     The organic layer  150  may further include a hole transport region disposed between the first electrode and the emission layer, and an electron transport region disposed between the emission layer and the second electrode. 
     In some embodiments, the hole transport region may include at least one selected from a hole transport layer (HTL), a hole injection layer (HIL), a buffer layer, and an electron blocking layer; and an electron transport region may include at least one selected from a hole blocking layer (HBL), an electron transport layer (ETL), and an electron injection layer (EIL). However, it may be understood that embodiments of the present disclosure are not limited thereto. 
     The hole transport region may have a single-layered structure formed of a single material, a single-layered structure formed of a plurality of different materials, or a multi-layered structure having a plurality of layers formed of a plurality of different materials. 
     For example, the hole transport region may have a single-layered structure formed of a plurality of different materials, or a structure of hole injection layer/hole transport layer, a structure of hole injection layer/hole transport layer/buffer layer, a structure of hole injection layer/buffer layer, a structure of hole transport layer/buffer layer, or a structure of hole injection layer/hole transport layer/electron blocking layer, wherein the layers of each structure are sequentially stacked from the first electrode  110  in this stated order, but the structure of the hole transport region is not limited thereto. 
     When the hole transport region includes a hole injection layer, the hole injection layer may be formed on the first electrode  110  by using one or more suitable methods such as vacuum deposition, spin coating, casting, a Langmuir-Blodgett (LB) method, ink-jet printing, laser-printing, and/or laser-induced thermal imaging. 
     When a hole injection layer is formed by vacuum deposition, for example, the vacuum deposition may be performed at a deposition temperature of about 100 to about 500° C., at a vacuum degree of about 10 −8  to about 10 −3  torr, and at a deposition rate of about 0.01 to about 100 Å/sec, by taking into account a compound for forming the hole injection layer to be deposited, and the structure of the hole injection layer to be formed. 
     When a hole injection layer is formed by spin coating, for example, the spin coating may be performed at a coating rate of about 2000 rpm to about 5000 rpm, and at a temperature of about 80° C. to 200° C., by taking into account a compound for forming the hole injection layer to be deposited, and the structure of the hole injection layer to be formed. 
     When the hole transport region includes a hole transport layer, the hole transport layer may be formed on the first electrode  110  or the hole injection layer by using one or more suitable methods such as vacuum deposition, spin coating, casting, a LB method, ink-jet printing, laser-printing, and/or laser-induced thermal imaging. 
     When the hole transport layer is formed by vacuum deposition and/or spin coating, deposition and coating conditions for the hole transport layer may be the same as (or substantially similar to) the deposition and coating conditions for the hole injection layer. 
     The hole transport region may include m-MTDATA, TDATA, 2-TNATA, NPB, β-NPB, TPD, Spiro-TPD, Spiro-NPB, methylated NPB, TAPC, HMTPD, 4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA), polyaniline/dodecylbenzenesulfonic acid (Pani/DBSA), poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS), polyaniline/camphor sulfonicacid (Pani/CSA), (polyaniline)/poly(4-styrenesulfonate) (PANI/PSS), a compound represented by Formula 201 below, and/or a compound represented by Formula 202 below: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     In Formulae 201 and 202, 
     L 201  to L 205  may each independently be selected from a substituted or unsubstituted C 6 -C 60  arylene group, a substituted or unsubstituted C 1 -C 60  heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group; 
     xa1 to xa4 may each independently be selected from 0, 1, 2, and 3; 
     xa5 may be selected from 1, 2, 3, 4, and 5; and 
     R 201  to R 204  may each independently be selected from a substituted or unsubstituted C 3 -C 10  cycloalkyl group, a substituted or unsubstituted C 2 -C 10  heterocycloalkyl group, a substituted or unsubstituted C 3 -C 10  cycloalkenyl group, a substituted or unsubstituted C 2 -C 10  heterocycloalkenyl group, a substituted or unsubstituted C 6 -C 60  aryl group, a substituted or unsubstituted C 6 -C 60  aryloxy group, a substituted or unsubstituted C 6 -C 60  arythio group, a substituted or unsubstituted C 1 -C 60  heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group. 
     In some embodiments, in Formulae 201 and 202, 
     L 201  to L 205  may each independently be selected from the group consisting of: 
     a phenylene group, a naphthylene group, a fluorenylene group, a spiro-fluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenanthrenylene group, an anthracenylene group, a pyrenylene group, a chrysenylene group, a pyridinylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, a quinolinylene group, an isoquinolinylene group, a quinoxalinylene group, a quinazolinylene group, a carbazolylene group, and a triazinylene group; and 
     a phenylene group, a naphthylene group, a fluorenylene group, a spiro-fluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenanthrenylene group, an anthracenylene group, a pyrenylene group, a chrysenylene group, a pyridinylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, a quinolinylene group, an isoquinolinylene group, a quinoxalinylene group, a quinazolinylene group, a carbazolylene group, and a triazinylene group, each substituted with at least one selected from 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 1 -C 20  alkyl group, a C 1 -C 20  alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group; 
     xa1 to xa4 may each independently be 0, 1, or 2; 
     xa5 may be 1, 2, or 3; 
     R 201  to R 204  may each independently be selected from the group consisting of: 
     a phenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group; and 
     a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group, each substituted with at least one selected from 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 1 -C 20  alkyl group, a C 1 -C 20  alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, an azulenyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group, but embodiments of the present disclosure are not limited thereto. 
     The compound represented by Formula 201 may be represented by Formula 201A: 
     
       
         
         
             
             
         
       
     
     For example, the compound represented by Formula 201 may be represented by Formula 201A-1 below, but is not limited thereto: 
     
       
         
         
             
             
         
       
     
     For example, the compound represented by Formula 202 may be represented by Formula 202A below, but is not limited thereto: 
     
       
         
         
             
             
         
       
     
     L 201  to L 203 , xa1 to xa3, xa5, and R 202  to R 204  in Formulae 201A, 201A-1 and 202A are already described above; the description of R 211  may be understood by referring to the description provided herein in connection with R 203 ; and R 213  to R 216  may each independently be selected from 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 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 2 -C 60  alkynyl group, a C 1 -C 60  alkoxy group, a C 3 -C 10  cycloalkyl group, a C 2 -C 10  heterocycloalkyl group, a C 3 -C 10  cycloalkenyl group, a C 2 -C 10  heterocycloalkenyl group, a C 6 -C 60  aryl group, a C 6 -C 60  aryloxy group, a C 6 -C 60  arylthio group, a C 1 -C 60  heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group. 
     For example, in Formulae 201A, 201A-1, and 202A, 
     L 201  to L 203  may each independently be selected from the group consisting of: 
     a phenylene group, a naphthylene group, a fluorenylene group, a spiro-fluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenanthrenylene group, an anthracenylene group, a pyrenylene group, a chrysenylene group, a pyridinylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, a quinolinylene group, an isoquinolinylene group, a quinoxalinylene group, a quinazolinylene group, a carbazolylene group, and a triazinylene group, and 
     a phenylene group, a naphthylene group, a fluorenylene group, a spiro-fluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenanthrenylene group, an anthracenylene group, a pyrenylene group, a chrysenylene group, a pyridinylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, a quinolinylene group, an isoquinolinylene group, a quinoxalinylene group, a quinazolinylene group, a carbazolylene group, and a triazinylene group, each substituted with at least one selected from 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 1 -C 20  alkyl group, a C 1 -C 20  alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group; 
     xa1 to xa3 may each independently be 0 or 1; 
     R 203 , R 211 , and R 212  may each independently be selected from the group consisting of: 
     a phenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group, and 
     a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group, each substituted with at least one selected from 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 1 -C 20  alkyl group, a C 1 -C 20  alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group; 
     R 213  and R 214  may each independently be selected from the group consisting of: 
     a C 1 -C 20  alkyl group and a C 1 -C 20  alkoxy group, 
     a C 1 -C 20  alkyl group and a C 1 -C 20  alkoxy group, each substituted with at least one selected from 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 phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group, 
     a phenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group, and 
     a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group, each substituted with at least one selected from 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 1 -C 20  alkyl group, a C 1 -C 20  alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group; and 
     R 215  and R 216  may each independently be selected from the group consisting of: 
     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 1 -C 20  alkyl group, and a C 1 -C 20  alkoxy group, 
     a C 1 -C 20  alkyl group and a C 1 -C 20  alkoxy group, each substituted with at least one selected from 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 phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group, 
     a phenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, and a triazinyl group, and 
     a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group, each substituted with at least one selected from 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 1 -C 20  alkyl group, a C 1 -C 20  alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group; and 
     xa5 may be 1 or 2. 
     In some embodiments, R 213  and R 214  in Formulae 201A and/or 201A-1 may be linked to each other to form a saturated or unsaturated ring. 
     The compound represented by Formula 201 and the compound represented by Formula 202 may each independently include any of compounds HT1 to HT20 illustrated below, but are not limited thereto. 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     A thickness of the hole transport region may be in a range of about 100 Å to about 10,000 Å, for example, about 100 Å to about 1,000 Å. When the hole transport region includes a hole injection layer and a hole transport layer, the thickness of the hole injection layer may be in a range of about 100 Å to about 10,000 Å, for example, about 100 Å to about 1,000 Å; and the thickness of the hole transport layer may be in a range of about 50 Å to about 2,000 Å, for example, about 100 Å to about 1,500 Å. When the thicknesses of the hole transport region, the hole injection layer and the hole transport layer are within any of these ranges, satisfactory (or suitable) hole transporting characteristics may be obtained without a substantial increase in driving voltage. 
     The hole transport region may further include, in addition to the materials described above, a charge-generation material for the improvement of conductive properties. The charge-generation material may be homogeneously or non-homogeneously dispersed in the hole transport region. 
     The charge-generation material may be, for example, a p-dopant. The p-dopant may be one selected from a quinone derivative, a metal oxide, and a cyano group-containing compound, but embodiments are not limited thereto. Non-limiting examples of the p-dopant include quinone derivatives (such as tetracyanoquinonedimethane (TCNQ) and/or 2,3,5,6-tetrafluoro-tetracyano-1,4-benzoquinonedimethane (F4-TCNQ)), metal oxides (such as tungsten oxide and/or molybdenum oxide), and Compound HT-D1 illustrated below. 
     
       
         
         
             
             
         
       
     
     The hole transport region may further include a buffer layer and/or an electron blocking layer, in addition to the hole injection layer and the hole transport layer. Since the buffer layer may compensate for an optical resonance distance according to a wavelength of light emitted from the emission layer, light-emission efficiency of the formed organic light-emitting device may be improved. For use as a material included in the buffer layer, any of the materials that are included in the hole transport region may be used. The electron blocking layer may function to prevent or reduce the injection of electrons from the electron transport region. 
     An emission layer may be formed on the first electrode  110  or the hole transport region by using one or more suitable methods such as vacuum deposition, spin coating, casting, a LB method, ink-jet printing, laser-printing, and/or laser-induced thermal imaging. When an emission layer is formed by vacuum deposition and/or spin coating, deposition and coating conditions for the emission layer may be the same as (or substantially similar to) those for the hole injection layer. 
     When the organic light-emitting device  10  is a full color organic light-emitting device, the emission layer may be patterned into a red emission layer, a green emission layer, and/or a blue emission layer, according to a sub pixel. In some embodiments, the emission layer may have a stacked structure of a red emission layer, a green emission layer, and a blue emission layer, or may include a red-light emission material, a green-light emission material, and a blue-light emission material, which are mixed with each other in a single layer, to emit white light. 
     The emission layer may include a host and a dopant. 
     For example, the host may include at least one selected from TPBi, TBADN, ADN (herein also referred to as “DNA”), CBP, CDBP, and TCP: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     In some embodiments, the host may include a compound represented by Formula 301 below:
 
Ar 301 -[(L 301 ) xb1 -R 301 ] xb2 .  &lt;Formula 301&gt;
 
     In Formula 301, 
     Ar 301  may be selected from the group consisting of: 
     a naphthalene, a heptalene, a fluorene, a spiro-fluorene, a benzofluorene, a dibenzofluorene, a phenalene, a phenanthrene, an anthracene, a fluoranthene, a triphenylene, a pyrene, a chrysene, a naphthacene, a picene, a perylene, a pentaphene, and an indenoanthracene, and 
     a naphthalene, a heptalene, a fluorene, a spiro-fluorene, a benzofluorene, a dibenzofluorene, a phenalene, a phenanthrene, an anthracene, a fluoranthene, a triphenylene, a pyrene, a chrysene, a naphthacene, a picene, a perylene, a pentaphene, and an indenoanthracene, each substituted with at least one selected from 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 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 2 -C 60  alkynyl group, a C 1 -C 60  alkoxy group, a C 3 -C 10  cycloalkyl group, a C 2 -C 10  heterocycloalkyl group, a C 3 -C 10  cycloalkenyl group, a C 2 -C 10  heterocycloalkenyl group, a C 6 -C 60  aryl group, a C 6 -C 60  aryloxy group, a C 6 -C 60  arylthio group, a C 1 -C 60  heteroaryl group, a monovalent non-aromatic condensed polycyclic group, monovalent non-aromatic condensed heteropolycyclic group, and —Si(Q 301 )(Q 3o2 )(Q 303 ) (where Q 301  to Q 303  may each independently be selected from hydrogen, a C 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 6 -C 60  aryl group, and a C 1 -C 60  heteroaryl group); 
     L 301  may be selected from a phenylene group, a naphthylene group, a fluorenylene group, a spiro-fluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenanthrenylene group, an anthracenylene group, a pyrenylene group, a chrysenylene group, a pyridinylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, a quinolinylene group, an isoquinolinylene group, a quinoxalinylene group, a quinazolinylene group, a carbazolylene group, and a triazinylene group, and 
     a phenylene group, a naphthylene group, a fluorenylene group, a spiro-fluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenanthrenylene group, an anthracenylene group, a pyrenylene group, a chrysenylene group, a pyridinylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, a quinolinylene group, an isoquinolinylene group, a quinoxalinylene group, a quinazolinylene group, a carbazolylene group, and a triazinylene group, each substituted with at least one selected from 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 1 -C 20  alkyl group, a C 1 -C 20  alkoxy group, a phenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group; 
     R 301  may be selected from the group consisting of: 
     a C 1 -C 20  alkyl group and a C 1 -C 20  alkoxy group, 
     a C 1 -C 20  alkyl group and a C 1 -C 20  alkoxy group, each substituted with at least one selected from 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 phenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group, 
     a phenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group, and 
     a phenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group, each substituted with at least one selected from 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 1 -C 20  alkyl group, a C 1 -C 20  alkoxy group, a phenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group; 
     xb1 may be selected from 0, 1, 2, and 3; and 
     xb2 may be selected from 1, 2, 3, and 4. 
     For example, in Formula 301, 
     L 301  may be selected from the group consisting of: 
     a phenylene group, a naphthylene group, a fluorenylene group, a spiro-fluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenanthrenylene group, an anthracenylene group, a pyrenylene group, and a chrysenylene group, and 
     a phenylene group, a naphthylene group, a fluorenylene group, a spiro-fluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenanthrenylene group, an anthracenylene group, a pyrenylene group, and a chrysenylene group, each substituted with at least one selected from 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 1 -C 20  alkyl group, a C 1 -C 20  alkoxy group, a phenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, and a chrysenyl group; 
     R 301  may be selected from the group consisting of: 
     a C 1 -C 20  alkyl group and a C 1 -C 20  alkoxy group, 
     a C 1 -C 20  alkyl group and a C 1 -C 20  alkoxy group, each substituted with at least one selected from 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 phenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, and a chrysenyl group, 
     a phenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, and a chrysenyl group, and 
     a phenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, and a chrysenyl group, each substituted with at least one selected from 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 1 -C 20  alkyl group, a C 1 -C 20  alkoxy group, a phenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, and a chrysenyl group, but embodiments of the present disclosure are not limited thereto. 
     For example, the host may include a compound represented by Formula 301A below: 
     
       
         
         
             
             
         
       
     
     Descriptions of substituents of Formula 301A may be understood by referring to their respective descriptions provided herein. 
     The compound represented by Formula 301 may include at least one of Compounds H1 to H42, but is not limited thereto: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     In some embodiments, the host may include at least one of Compounds H43 to H49 below, but is not limited thereto: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     The dopant may include any suitable fluorescent dopant and/or phosphorescent dopant. 
     The phosphorescent dopant may include an organometallic complex represented by Formula 401 below: 
     
       
         
         
             
             
         
       
     
     In Formula 401, 
     M may be selected from iridium (Ir), platinum (Pt), osmium (Os), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu), terbium (Tb), and thulium (Tm); 
     X 401  to X 404  may each independently be nitrogen or carbon; 
     A 401  and A 402  rings may each independently be selected from a substituted or unsubstituted benzene, a substituted or unsubstituted naphthalene, a substituted or unsubstituted fluorene, a substituted or unsubstituted spiro-fluorene, a substituted or unsubstituted indene, a substituted or unsubstituted pyrrole, a substituted or unsubstituted thiophene, a substituted or unsubstituted furan, a substituted or unsubstituted imidazole, a substituted or unsubstituted pyrazole, a substituted or unsubstituted thiazole, a substituted or unsubstituted isothiazole, a substituted or unsubstituted oxazole, a substituted or unsubstituted isoxazole, a substituted or unsubstituted pyridine, a substituted or unsubstituted pyrazine, a substituted or unsubstituted pyrimidine, a substituted or unsubstituted pyridazine, a substituted or unsubstituted quinoline, a substituted or unsubstituted isoquinoline, a substituted or unsubstituted benzoquinoline, a substituted or unsubstituted quinoxaline, a substituted or unsubstituted quinazoline, a substituted or unsubstituted carbazole, a substituted or unsubstituted benzoimidazole, a substituted or unsubstituted benzofuran, a substituted or unsubstituted benzothiophene, a substituted or unsubstituted isobenzothiophene, a substituted or unsubstituted benzoxazole, a substituted or unsubstituted isobenzoxazole, a substituted or unsubstituted triazole, a substituted or unsubstituted oxadiazole, a substituted or unsubstituted triazine, a substituted or unsubstituted dibenzofuran, and a substituted or unsubstituted dibenzothiophene; and 
     at least one substituent of the substituted benzene, substituted naphthalene, substituted fluorene, substituted spiro-fluorene, substituted indene, substituted pyrrole, substituted thiophene, substituted furan, substituted imidazole, substituted pyrazole, substituted thiazole, substituted isothiazole, substituted oxazole, substituted isoxazole, substituted pyridine, substituted pyrazine, substituted pyrimidine, substituted pyridazine, substituted quinoline, substituted isoquinoline, substituted benzoquinoline, substituted quinoxaline, substituted quinazoline, substituted carbazol, substituted benzoimidazole, substituted benzofuran, substituted benzothiophene, substituted isobenzothiophene, substituted benzoxazole, substituted isobenzoxazole, substituted triazole, substituted oxadiazole, substituted triazine, substituted dibenzofuran, and substituted dibenzothiophene may be selected from the group consisting of: 
     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 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 2 -C 60  alkynyl group, and a C 1 -C 60  alkoxy group, 
     a C 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 2 -C 60  alkynyl group, and a C 1 -C 60  alkoxy group, each substituted with at least one selected from 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 3 -C 10  cycloalkyl group, a C 2 -C 10  heterocycloalkyl group, a C 3 -C 10  cycloalkenyl group, a C 2 -C 10  heterocycloalkenyl group, a C 6 -C 60  aryl group, a C 6 -C 60  aryloxy group, a C 6 -C 60  arylthio group, a C 1 -C 60  heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q 401 )(Q 402 ), —Si(Q 403 )(Q 404 )(Q 405 ), and —B(Q 406 )(Q 407 ), 
     a C 3 -C 10  cycloalkyl group, a C 2 -C 10  heterocycloalkyl group, a C 3 -C 10  cycloalkenyl group, a C 2 -C 10  heterocycloalkenyl group, a C 6 -C 60  aryl group, a C 6 -C 60  aryloxy group, a C 6 -C 60  arylthio group, a C 1 -C 60  heteroaryl group, and a non-aromatic condensed polycyclic group, 
     a C 3 -C 10  cycloalkyl group, a C 2 -C 10  heterocycloalkyl group, a C 3 -C 10  cycloalkenyl group, a C 2 -C 10  heterocycloalkenyl group, a C 6 -C 60  aryl group, a C 6 -C 60  aryloxy group, a C 6 -C 60  arylthio group, a C 1 -C 60  heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from 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 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 2 -C 60  alkynyl group, a C 1 -C 60  alkoxy group, a C 3 -C 10  cycloalkyl group, a C 2 -C 10  heterocycloalkyl group, a C 3 -C 10  cycloalkenyl group, a C 2 -C 10  heterocycloalkenyl group, a C 6 -C 60  aryl group, a C 6 -C 60  aryloxy group, a C 6 -C 60  arylthio group, a C 1 -C 60  heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q 411 )(Q 412 ), —Si(Q 413 )(Q 414 )(Q 415 ) and —B(Q 416 )(Q 417 ), and 
     —N(Q 421 )(Q 422 ), −Si(Q 423 )(Q 424 )(Q 425 ), and —B(Q 426 )(Q 427 ), 
     wherein Q 401  to Q 407 , Q 411  to Q 417  and Q 421  to Q 427  may each independently be selected from 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 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 2 -C 60  alkynyl group, a C 1 -C 60  alkoxy group, a C 3 -C 10  cycloalkyl group, a C 2 -C 10  heterocycloalkyl group, a C 3 -C 10  cycloalkenyl group, a C 2 -C 10  heterocycloalkenyl group, a C 6 -C 60  aryl group, a C 1 -C 60  heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group; 
     L 401  may be an organic ligand; 
     xc1 may be 1, 2, or 3; and 
     xc2 may be 0, 1, 2, or 3. 
     In Formula 401, L 401  may be a monovalent, divalent, or trivalent organic ligand. For example, L 401  may be selected from a halogen ligand (e.g., Cl and/or F), a diketone ligand (e.g., acetylacetonate, 1,3-diphenyl-1,3-propanedionate, 2,2,6,6-tetramethyl-3,5-heptanedionate, and/or hexafluoroacetonate), a carboxylic acid ligand (e.g., picolinate, dimethyl-3-pyrazolecarboxylate, and/or benzoate), a carbon monooxide ligand, an isonitrile ligand, a cyano ligand, and a phosphorous ligand (e.g., phosphine and/or phosphite), but is not limited thereto. 
     When A 401  in Formula 401 has two or more substituents, the plurality of substituents of A 401  may be linked to form a saturated or unsaturated ring. 
     When A 401  in Formula 402 has two or more substituents, the plurality of substituents of A 402  may be linked to form a saturated or unsaturated ring. 
     
       
         
         
             
             
         
       
     
     When xc1 in Formula 401 is two or more, a plurality of ligands in Formula 401 may be identical to or different from each other. When xc1 in Formula 401 is two or more, A 401  and A 402  of one ligand may each independently be respectively connected to A 401  and A 402  of other neighboring ligands, either directly (e.g., via a bond such as a single bond) or with a linker (e.g., a C 1 -C 5  alkylene, —N(R′)— (where R′ may be a C 1 -C 10  alkyl group or a C 6 -C 20  aryl group), and/or —C(═O)—) therebetween. 
     The phosphorescent dopant may include at least one of Compounds PD1 to PD74 below, but is not limited thereto: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     In some embodiments, the phosphorescent dopant may include PtOEP: 
     
       
         
         
             
             
         
       
     
     The fluorescent dopant may include at least one selected from DPVBi, DPAVBi, TBPe, DCM, DCJTB, Coumarin 6, and C545T. 
     
       
         
         
             
             
         
       
     
     In some embodiments, the fluorescent dopant may include a compound represented by Formula 501 below. 
     
       
         
         
             
             
         
       
     
     In Formula 501, 
     Ar 501  may be selected from the group consisting of: 
     a naphthalene, a heptalene, a fluorene, a spiro-fluorene, a benzofluorene, a dibenzofluorene, a phenalene, a phenanthrene, an anthracene, a fluoranthene, a triphenylene, a pyrene, a chrysene, a naphthacene, a picene, a perylene, a pentaphene, and an indenoanthracene, and 
     a naphthalene, a heptalene, a fluorene, a spiro-fluorene, a benzofluorene, a dibenzofluorene, a phenalene, a phenanthrene, an anthracene, a fluoranthene, a triphenylene, a pyrene, a chrysene, a naphthacene, a picene, a perylene, a pentaphene, and an indenoanthracene, each substituted with at least one selected from 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 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 2 -C 60  alkynyl group, a C 1 -C 60  alkoxy group, a C 3 -C 10  cycloalkyl group, a C 2 -C 10  heterocycloalkyl group, a C 3 -C 10  cycloalkenyl group, a C 2 -C 10  heterocycloalkenyl group, a C 6 -C 60  aryl group, a C 6 -C 60  aryloxy group, a C 6 -C 60  arylthio group, a C 1 -C 60  heteroaryl group, a monovalent non-aromatic condensed polycyclic group, monovalent non-aromatic condensed heteropolycyclic group, and —Si(Q 501 )(Q 502 )(Q 503 ) (where Q 501  to Q 503  may each independently be selected from hydrogen, a C 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 6 -C 60  aryl group, and a C 1 -C 60  heteroaryl group); 
     descriptions of L 501  to L 503  may each independently be the same as the description provided herein in connection with L 203 ; 
     R 501  and R 502  may each independently be selected from the group consisting of: 
     a phenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a triazinyl group, a dibenzofuranyl group, and a dibenzothiophenyl group, and 
     a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a triazinyl group, a dibenzofuranyl group, and a dibenzothiophenyl group, each substituted with at least one selected from 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 1 -C 20  alkyl group, a C 1 -C 20  alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a triazinyl group, a dibenzofuranyl group, and a dibenzothiophenyl group; 
     xd1 to xd3 may each independently be selected from 0, 1, 2, and 3; and 
     xb4 may be selected from 1, 2, 3, and 4. 
     For example, the fluorescent dopant may include at least one of Compounds FD1 to FD8: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     An amount of the dopant in the emission layer may be, for example, in a range of about 0.01 to about 15 parts by weight based on 100 parts by weight of the host, but is not limited thereto. 
     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 any of these ranges, excellent (or suitable) light-emission characteristics may be obtained without a substantial increase in driving voltage. 
     An electron transport region may be disposed on the emission layer. 
     The electron transport region may include at least one selected from a hole blocking layer, an electron transport layer (ETL), and an electron injection layer, but is not limited thereto. 
     In some embodiments, the electron transport region may include the compound of Formula 1 according to an embodiment of the present disclosure. 
     When the electron transport region includes a hole blocking layer, the hole blocking layer may be formed on the emission layer by using one or more suitable methods such as vacuum deposition, spin coating, casting, a Langmuir-Blodgett (LB) method, ink-jet printing, laser-printing, and/or laser-induced thermal imaging. When the hole blocking layer is formed by vacuum deposition and/or spin coating, deposition and coating conditions for the hole blocking layer may be determined by referring to the deposition and coating conditions for the hole injection layer. 
     The hole blocking layer may include, for example, at least one selected from BCP and Bphen, but is not limited thereto: 
     
       
         
         
             
             
         
       
     
     A thickness of the hole blocking layer may be in a range of about 20 Å to about 1,000 Å, for example, about 30 Å to about 300 Å. When the thickness of the hole blocking layer is within any of these ranges, the hole blocking layer may have excellent (or suitable) hole blocking characteristics without a substantial increase in driving voltage. 
     The electron transport region may be disposed between the emission layer and the second electrode, and may include an electron transport layer and at least one selected from a hole blocking layer and an electron injection layer. 
     For example, the electron transport region may have a structure of electron transport layer/electron injection layer or a structure of hole blocking layer/electron transport layer/electron injection layer, wherein the layers of each structure are sequentially stacked from the emission layer in the stated order, but the structure of the electron transport region is not limited thereto. 
     According to an embodiment, the organic layer  150  of the organic light-emitting device includes an electron transport region disposed between the emission layer and the second electrode  190 , and the electron transport region may include an electron transport layer. The electron transport layer may include a plurality of layers. For example, the electron transport layer may include a first electron transport layer and a second electron transport layer. 
     The electron transport layer may include the compound of Formula 1 according to an embodiment of the present disclosure. 
     A thickness of the electron transport layer may be in a 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 any of the ranges described above, the electron transport layer may have satisfactory (or suitable) electron transport characteristics without a substantial increase in driving voltage. 
     The electron transport layer may further include, in addition to the materials described above, a metal-containing material. 
     The metal-containing material may include a Li complex. The Li complex may include, for example, Compound ET-D1 (lithium quinolate, LiQ) and/or Compound ET-D2. 
     
       
         
         
             
             
         
       
     
     In some embodiments, the electron transport region may include an electron injection layer that facilitates injection of electrons from the second electrode  190 . 
     The electron injection layer may be formed on the electron transport layer by using one or more suitable methods such as vacuum deposition, spin coating, casting, a LB method, ink-jet printing, laser-printing, and/or laser-induced thermal imaging. When an electron injection layer is formed by vacuum deposition and/or spin coating, deposition and coating conditions for the electron injection layer may be the same as (or substantially similar to) those for the hole injection layer. 
     The electron injection layer may include at least one selected from LiF, NaCl, CsF, Li 2 O, BaO, and LiQ. 
     A thickness of the electron injection layer may be in a range of about 1 Å to about 100 Å, for example, about 3 Å to about 90 Å. When the thickness of the electron injection layer is within any of the ranges described above, the electron injection layer may have satisfactory (or suitable) electron injection characteristics without a substantial increase in driving voltage. 
     The second electrode  190  may be disposed on the organic layer  150  having the structure according to embodiments of the present disclosure. The second electrode  190  may be a cathode, which is an electron injection electrode, and in this regard, a material for forming the second electrode  190  may be selected from a metal, an alloy, an electrically conductive compound, and a mixture thereof, which have a relatively low work function. Non-limiting examples of the material for forming the second electrode  190  include lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), and magnesium-silver (Mg—Ag). In some embodiments, the material for forming the second electrode  190  may be ITO and/or IZO. The second electrode  190  may be a reflective electrode, a semi-transmissive electrode, or a transmissive electrode. 
     An organic layer according to an embodiment of the present disclosure may be formed by depositing the compound according to an embodiment, or may be formed by using a wet method in which the compound according to an embodiment is prepared in the form of a solution and then the solution of the compound is used for coating. 
     An organic light-emitting device according to an embodiment may be used in various flat panel display apparatuses, such as a passive matrix organic light-emitting display apparatus and/or an active matrix organic light-emitting display apparatus. For example, when the organic light-emitting device is included in an active matrix organic light-emitting display apparatus, a first electrode disposed on a substrate may act as a pixel electrode and may be electrically connected (e.g., coupled) to a source electrode or a drain electrode of a thin film transistor. In addition, the organic light-emitting device may be included in a flat panel display apparatus that emits light in opposite directions (e.g., emits light from both sides of a display panel). 
     Hereinbefore, the organic light-emitting device has been described with reference to the drawing, but embodiments of the present disclosure are not limited thereto. 
     Hereinafter, definitions of substituents used herein will be presented. The number of carbon atoms used to restrict a substituent is not limited, and does not limit properties of the substituent, and unless defined otherwise, the definition of the substituent is consistent with a general definition thereof. 
     A C 1 -C 60  alkyl group used herein may refer to a linear or branched aliphatic hydrocarbon monovalent group having 1 to 60 carbon atoms, and non-limiting examples thereof are a methyl group, an ethyl group, a propyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an iso-amyl group, and a hexyl group. A C 1 -C 60  alkylene group used herein may refer to a divalent group having the same structure as the C 1 -C 60  alkyl group. 
     A C 1 -C 60  alkoxy group used herein may refer to a monovalent group represented by —OA 101  (wherein A 101  is the C 1 -C 60  alkyl group), and non-limiting examples thereof are a methoxy group, an ethoxy group, and an isopropoxy group. 
     A C 2 -C 60  alkenyl group used herein may refer to a hydrocarbon group having at least one carbon double bond at one or more positions along the hydrocarbon chain of the C 2 -C 60  alkyl group (e.g., in the middle or at either terminal end of the C 2 -C 60  alkyl group), and non-limiting examples thereof are an ethenyl group, a propenyl group, and a butenyl group. A C 2 -C 60  alkenylene group used herein may refer to a divalent group having the same structure as the C 2 -C 60  alkenyl group. 
     A C 2 -C 60  alkynyl group used herein may refer to a hydrocarbon group having at least one carbon triple bond at one or more positions along the hydrocarbon chain of the C 2 -C 60  alkyl group (e.g., in the middle or at either terminal end of the C 2 -C 60  alkyl group), and non-limiting examples thereof are an ethynyl group and a propynyl group. A C 2 -C 60  alkynylene group used herein may refer to a divalent group having the same structure as the C 2 -C 60  alkynyl group. 
     A C 3 -C 10  cycloalkyl group used herein may refer to a monovalent hydrocarbon monocyclic group having 3 to 10 carbon atoms, and non-limiting examples thereof are a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group. A C 3 -C 10  cycloalkylene group used herein may refer to a divalent group having the same structure as the C 3 -C 10  cycloalkyl group. 
     A C 2 -C 10  heterocycloalkyl group used herein may refer to a monovalent monocyclic group having at least one heteroatom selected from N, O, P, and S as a ring-forming atom, and 2 to 10 carbon atoms, and non-limiting examples thereof are a tetrahydrofuranyl group and a tetrahydrothiophenyl group. A C 2 -C 10  heterocycloalkylene group used herein may refer to a divalent group having the same structure as the C 2 -C 10  heterocycloalkyl group. 
     A C 3 -C 10  cycloalkenyl group used herein may refer to a monovalent monocyclic group that has 3 to 10 carbon atoms and at least one double bond in the ring thereof and does not have aromaticity, and non-limiting examples thereof are a cyclopentenyl group, a cyclohexenyl group, and a cycloheptenyl group. A C 3 -C 10  cycloalkenylene group used herein may refer to a divalent group having the same structure as the C 3 -C 10  cycloalkenyl group. 
     A C 2 -C 10  heterocycloalkenyl group used herein may refer to a monovalent monocyclic group that has at least one heteroatom selected from N, O, P, and S as a ring-forming atom, 2 to 10 carbon atoms, and at least one double bond in its ring. Non-limiting examples of the C 2 -C 10  heterocycloalkenyl group are a 2,3-hydrofuranyl group and a 2,3-hydrothiophenyl group. A C 2 -C 10  heterocycloalkenylene group used herein may refer to a divalent group having the same structure as the C 2 -C 10  heterocycloalkenyl group. 
     A C 6 -C 60  aryl group used herein may refer to a monovalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms, and a C 6 -C 60  arylene group used herein may refer to a divalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms. Non-limiting examples of the C 6 -C 60  aryl group are a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenyl group, and a chrysenyl group. When the C 6 -C 60  aryl group and the C 6 -C 60  arylene group each independently include two or more rings, the respective rings may be fused to each other. 
     A C 1 -C 60  heteroaryl group used herein may refer to a monovalent group having a carbocyclic aromatic system that has at least one heteroatom selected from N, O, P, and S as a ring-forming atom, and 1 to 60 carbon atoms. A C 1 -C 60  heteroarylene group used herein may refer to a divalent group having a carbocyclic aromatic system that has at least one heteroatom selected from N, O, P, and S as a ring-forming atom, and 1 to 60 carbon atoms. Non-limiting examples of the C 1 -C 60  heteroaryl group are 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 1 -C 60  heteroaryl group and the C 1 -C 60  heteroarylene group each independently include two or more rings, the respective rings may be fused to each other. 
     A C 6 -C 60  aryloxy group used herein may refer to a monovalent group represented by —OA 102  (where A 102  is the C 6 -C 60  aryl group), and a C 6 -C 60  arylthio group may refer to a monovalent group represented by —SA 103  (where A 103  is the C 6 -C 60  aryl group). 
     A monovalent non-aromatic condensed polycyclic group used herein may refer to a monovalent group that has two or more rings condensed (e.g., fused) to each other, only carbon atoms as ring forming atoms (e.g., 8 to 60 carbon atoms), and non-aromaticity in the entire molecular structure (e.g., does not have overall aromaticity). A non-limiting example of the monovalent non-aromatic condensed polycyclic group is a fluorenyl group. A divalent non-aromatic condensed polycyclic group used herein may refer to a divalent group having the same structure as the monovalent non-aromatic condensed polycyclic group. 
     A monovalent non-aromatic condensed heteropolycyclic group used herein may refer to a monovalent group that has two or more rings condensed (e.g., fused) to each other, has at least one heteroatom selected from N, O, P, and S, other than carbon atoms (e.g., 2 to 60 carbon atoms), as ring forming atoms, and has non-aromaticity in the entire molecular structure (e.g., does not have overall aromaticity). A divalent non-aromatic condensed heteropolycyclic group used herein may refer to a divalent group having the same structure as the monovalent non-aromatic condensed heteropolycyclic group. 
     As used herein, at least one substituent of the substituted C 3 -C 10  cycloalkylene group, substituted C 2 -C 10  heterocycloalkylene group, substituted C 3 -C 1  cycloalkenylene group, substituted C 2 -C 10  heterocycloalkenylene group, substituted C 6 -C 60  arylene group, substituted C 1 -C 60  heteroarylene group, a substituted divalent non-aromatic condensed polycyclic group, a substituted divalent non-aromatic condensed heteropolycyclic group, substituted C 1 -C 60  alkyl group, substituted C 2 -C 60  alkenyl group, substituted C 2 -C 60  alkynyl group, substituted C 1 -C 60  alkoxy group, substituted C 3 -C 10  cycloalkyl group, substituted C 2 -C 10  heterocycloalkyl group, substituted C 3 -C 10  cycloalkenyl group, substituted C 2 -C 10  heterocycloalkenyl group, substituted C 6 -C 60  aryl group, substituted C 6 -C 60  aryloxy group, substituted C 6 -C 60  arylthio group, substituted C 1 -C 60  heteroaryl group, substituted monovalent non-aromatic condensed polycyclic group, and substituted monovalent non-aromatic condensed heteropolycyclic group may be selected from the group consisting of: 
     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 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 2 -C 60  alkynyl group, and a C 1 -C 60  alkoxy group, 
     a C 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 2 -C 60  alkynyl group, and a C 1 -C 60  alkoxy group, each substituted with at least one selected from 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 3 -C 10  cycloalkyl group, a C 2 -C 10  heterocycloalkyl group, a C 3 -C 10  cycloalkenyl group, a C 2 -C 10  heterocycloalkenyl group, a C 6 -C 60  aryl group, a C 6 -C 60  aryloxy group, a C 6 -C 60  arylthio group, a C 1 -C 60  heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q 11 )(Q 12 ), —Si(Q 13 )(Q 14 )(Q 15 ), and —B(Q 16 )(Q 17 ), 
     a C 3 -C 10  cycloalkyl group, a C 2 -C 10  heterocycloalkyl group, a C 3 -C 10  cycloalkenyl group, a C 2 -C 10  heterocycloalkenyl group, a C 6 -C 60  aryl group, a C 6 -C 60  aryloxy group, a C 6 -C 60  arylthio group, a C 1 -C 60  heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, 
     a C 3 -C 10  cycloalkyl group, a C 2 -C 10  heterocycloalkyl group, a C 3 -C 10  cycloalkenyl group, a C 2 -C 10  heterocycloalkenyl group, a C 6 -C 60  aryl group, a C 6 -C 60  aryloxy group, a C 6 -C 60  arylthio group, a C 1 -C 60  heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from 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 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 2 -C 60  alkynyl group, a C 1 -C 60  alkoxy group, a C 3 -C 10  cycloalkyl group, a C 2 -C 10  heterocycloalkyl group, a C 3 -C 10  cycloalkenyl group, a C 2 -C 10  heterocycloalkenyl group, a C 6 -C 60  aryl group, a C 6 -C 60  aryloxy group, a C 6 -C 60  arylthio group, a C 1 -C 60  heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q 21 )(Q 22 ), —Si(Q 23 )(Q 24 )(Q 25 ) and —B(Q 26 )(Q 27 ), and 
     —N(Q 31 )(Q 32 ), —Si(Q 33 )(Q 34 )(Q 35 ) and —B(Q 36 )(Q 37 ), 
     wherein Q 11  to Q 17 , Q 21  to Q 27  and Q 31  to Q 37  may each independently be selected from 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 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 2 -C 60  alkynyl group, a C 1 -C 60  alkoxy group, a C 3 -C 10  cycloalkyl group, a C 2 -C 1  heterocycloalkyl group, a C 3 -C 10  cycloalkenyl group, a C 2 -C 10  heterocycloalkenyl group, a C 6 -C 60  aryl group, a C 1 -C 60  heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group. 
     For example, at least one substituent of the substituted C 3 -C 10  cycloalkylene group, substituted C 2 -C 10  heterocycloalkylene group, substituted C 3 -C 10  cycloalkenylene group, substituted C 2 -C 10  heterocycloalkenylene group, substituted C 6 -C 60  arylene group, substituted C 1 -C 60  heteroarylene group, a substituted divalent non-aromatic condensed polycyclic group, a substituted divalent non-aromatic condensed heteropolycyclic group, substituted C 1 -C 60  alkyl group, substituted C 2 -C 60  alkenyl group, substituted C 2 -C 60  alkynyl group, substituted C 1 -C 60  alkoxy group, substituted C 3 -C 10  cycloalkyl group, substituted C 2 -C 10  heterocycloalkyl group, substituted C 3 -C 10  cycloalkenyl group, substituted C 2 -C 10  heterocycloalkenyl group, substituted C 6 -C 60  aryl group, substituted C 6 -C 60  aryloxy group, substituted C 6 -C 60  arylthio group, substituted C 1 -C 60  heteroaryl group, substituted monovalent non-aromatic condensed polycyclic group, and substituted monovalent non-aromatic condensed heteropolycyclic group may be selected from the group consisting of: 
     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 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 2 -C 60  alkynyl group, and a C 1 -C 60  alkoxy group, 
     a C 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 2 -C 60  alkynyl group, and a C 1 -C 60  alkoxy group, each substituted with at least one selected from 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 cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl 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-fluorenyl 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 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 phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzoimidazolyl 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, a thiadiazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, —N(Q 11 )(Q 12 ), —Si(Q 13 )(Q 14 )(Q 15 ), and —B(Q 16 )(Q 17 ), 
     a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl 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-fluorenyl 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 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 phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzoimidazolyl 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, a thiadiazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group, 
     a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl 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-fluorenyl 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 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 phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzoimidazolyl 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, a thiadiazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group, each substituted with at least one selected from 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 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 2 -C 60  alkynyl group, a C 1 -C 60  alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl 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-fluorenyl 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 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 phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzoimidazolyl 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, a thiadiazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, —N(Q 21 )(Q 22 ), —Si(Q 23 )(Q 24 )(Q 25 ), and —B(Q 26 )(Q 27 ), and 
     —N(Q 31 )(Q 32 ), —Si(Q 33 )(Q 34 )(Q 35 ), and —B(Q 36 )(Q 37 ), 
     wherein Q 11  to Q 17 , Q 21  to Q 27 , and Q 31  to Q 37  may each independently be selected from 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 1 -C 60  alkyl group, a C 2 -C 60  alkenyl group, a C 2 -C 60  alkynyl group, a C 1 -C 60  alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl 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-fluorenyl 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 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 phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzoimidazolyl 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, a thiadiazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group. 
     The expression “Ph” used herein may refer to a phenyl group, the expression “Me” used herein may refer to a methyl group, the expression “Et” used herein may refer to an ethyl group, the expression “ter-Bu” or “Bu t ” used herein may refer to a tert-butyl group, and “D” may refer to deuterium. 
     Hereinafter, an organic light-emitting device according to one or more embodiments of the present disclosure will be described in more detail with reference to Synthesis Examples and Examples. 
     SYNTHESIS EXAMPLE 
     Synthesis Example 1: Synthesis of Compound 2 
                                           
Synthesis of Intermediate I-1
 
     2.58 g (10 mmol) of 10-bromobenzo[h]quinoline was dissolved in 40 mL of tetrahydrofuran (THF), and then 4 mL of n-butyllithium (n-BuLi) (2.5 molar (M) in hexane) was added thereto at −78° C. 1 hour after the addition, at the same temperature, 2.0 mL (10 mmol) of 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane was added thereto. The result was stirred at ambient temperature for 10 hours, water was added thereto, and the result washed three times with 30 mL of diethyl ether. The washed diethyl ether layer was dried by using magnesium sulfate (MgSO 4 ) and then dried under reduced pressure to obtain a product, which was then separation-purified by silica gel column chromatography, thereby completing the preparation of 1.86 g of Intermediate I-1 (yield: 61%). The obtained compound was identified by liquid chromatography-mass spectrometry (LC-MS). C 19 H 20 BNO 2 : M+1 306.2. 
     Synthesis of Intermediate I-2 
     3.05 g (10.0 mmol) of Intermediate I-1, 2.02 g (10.0 mmol) of 1-bromo-2-nitrobenzene, 0.58 g (0.50 mmol) of Pd(PPh 3 ) 4 , 0.16 g (0.5 mmol) of tetrabutylammonium bromide (TBAB), and 3.18 g (30.0 mmol) of Na 2 CO 3  were dissolved in 60 mL of a toluene/ethanol/H 2 O (3/3/1) mixed solution, and then, the resulting mixture was stirred at a temperature of 80° C. for 16 hours. The obtained reaction solution was cooled to ambient temperature, and then, an extraction process was performed thereon three times by using 60 mL of water and 60 mL of diethyl ether. An organic layer obtained therefrom was dried by using MgSO 4  and the residual obtained by evaporating a solvent therefrom was separation-purified by silica gel column chromatography, thereby completing the preparation of 2.34 g of Intermediate I-2 (yield: 78%). The obtained compound was identified by LC-MS. C 19 H 12 N 2 O 2 : M+1 301.1. 
     Synthesis of Intermediate I-3 
     3.00 g (10.0 mmol) of Intermediate I-2, 3.56 g (30 mmol) of tin, and 5 mL (50 mmol, conc. 36.5%) of hydrochloric acid were dissolved in 60 mL of ethanol, and then the mixture was stirred at a temperature of 100° C. for 8 hours. The reaction solution was cooled to ambient temperature, and 3 g of sodium hydroxide dissolved in 10 mL of water was added to a filtrate obtained by performing filtration of the reaction solution under reduced pressure, and an extraction process was performed thereon three times by using 60 mL of water and 60 mL of dichloromethane. An organic layer obtained therefrom was dried by using MgSO 4  and the residual obtained by evaporating a solvent therefrom was separation-purified by silica gel column chromatography, thereby completing the preparation of 2.51 g of Intermediate I-3 (yield: 93%). The obtained compound was identified by LC-MS. C 19 H 14 N 2 : M+1 271.1. 
     Synthesis of Intermediate I-4 
     2.70 g (10 mmol) of Intermediate I-3 was dissolved in 30 mL of THF, 4 mL of triethanolamine (TEA) and 3.29 g (15 mmol) of 4-bromobenzoyl chloride were slowly added thereto at a temperature of 0° C., and then the resulting mixture was stirred at ambient temperature for about 10 hours. Once the reaction was complete, an extraction process was performed thereon three times by using 40 mL of water and 40 mL of ethylacetate. An organic layer obtained therefrom was dried by using MgSO 4  and the residual obtained by evaporating a solvent therefrom was separation-purified by silica gel column chromatography, thereby completing the preparation of 3.62 g of Intermediate I-4 (yield: 80%). The obtained compound was identified by LC-MS. C 26 H 17 BrN 2 O: M+1 453.1. 
     Synthesis of Intermediate I-5 
     4.53 g (10 mmol) of Intermediate I-4 and P 2 O 5  were dissolved in 60 mL of POCl 3 , and then the resulting mixture was stirred at a temperature of 105° C. for 24 hours. Once the reaction was complete, the solvent was removed therefrom, neutralized using NaOH, and an extraction process was performed thereon by using ethyl acetate. An organic layer obtained therefrom was dried by using MgSO 4  and the residual obtained by evaporating a solvent therefrom was separation-purified by silica gel column chromatography, thereby completing the preparation of 2.61 g of Intermediate I-5 (yield: 66%). The obtained compound was identified by LC-MS. C 26 H 15 BrN 2 : M+1 435.0. 
     Synthesis of Intermediate I-6 
     3.57 g of Intermediate I-6 (yield: 74%) was obtained in the same (or substantially the same) manner as in Synthesis of Intermediate I-1, except that Intermediate I-5 was used instead of 10-bromobenzo[h]quinoline. The obtained compound was identified by LC-MS. C 32 H 27 BN 2 O 2 : M+1 483.2. 
     Synthesis of Compound 2 
     4.82 g (10 mmol) of Intermediate I-6, 2.68 g (10 mmol) of 2-chloro-4,6-diphenyl-1,3,5-triazine, 0.58 g (0.5 mmol) of tetrakis(triphenylphosphine)palladium (Pd(PPh 3 ) 3 ), and 4.14 g (30 mmol) of K 2 CO 3  were dissolved in 60 mL of a mixture solution of THF and H 2 O (at a volume ratio of 2:1), and stirred at 80° C. for 16 hours. The resulting solution was allowed to come to ambient temperature. Then, an extraction process was performed thereon three times by using each of 40 mL of water and 50 mL of ethyl ether. The obtained organic layer was dried by using MgSO 4 . A solvent was next removed therefrom by evaporation. The residual was separation-purified through silica gel column chromatography, thereby completing the preparation of 4.41 g of Compound 2 (yield: 75%). The obtained compound was identified by mass spectroscopy/fast atom bombardment (MS/FAB) and  1 H nuclear magnetic resonance (NMR). Cc H 25 N 5  cal. 587.21. found 587.20. 
     Synthesis Example 2: Synthesis of Compound 15 
     
       
         
         
             
             
         
       
     
     4.35 g (10 mmol) of Intermediate I-5 was dissolved in 60 mL of THF, and then 4 mL of n-BuLi (2.5 M in hexane) was added thereto at −78° C. One hour after the addition of n-BuLi, 2.20 g (10 mmol) of chlorodiphenyl phosphine was slowly added dropwise thereto, and then the result was stirred for about 3 hours and heated up to ambient temperature. Water was added thereto and the result was washed with 30 mL of ethyl acetate three times. The washed ethyl acetate layer was dried by using MgSO 4  and then dried under reduced pressure to obtain Intermediate I-7. Intermediate I-7 was dissolved in 40 mL of dichloromethane, 4 mL of hydrogen peroxide was added thereto, and the resulting solution was stirred at ambient temperature for about 20 hours. 20 mL of water was then added thereto, and an extraction process was performed three times thereon using 20 mL of dichloromethane. The obtained organic layer was dried by using MgSO 4 . A solvent was next removed therefrom by evaporation. The residual was separation-purified through silica gel column chromatography, thereby completing the preparation of 3.89 g of Compound 15 (yield: 70%). The obtained compound was identified by MS/FAB and  1 H NMR. C 38 H 25 N 2 OP cal. 556.17. found 556.18. 
     Synthesis Example 3: Synthesis of Compound 33 
                         
Synthesis of Intermediate I-8
 
     3.40 g of Intermediate I-8 (yield: 75%) was obtained in the same (or substantially the same) manner as in Synthesis of Intermediate I-4, except that 3-bromobenzoyl chloride was used instead of 4-bromobenzoyl chloride. The obtained compound was identified by LC-MS. C 26 H 17 BrN 2 O: M+1 453.1. 
     Synthesis of Intermediate I-9 
     3.00 g of Intermediate I-9 (yield: 69%) was obtained in the same (or substantially the same) manner as in Synthesis of Intermediate I-5, except that Intermediate I-8 was used instead of Intermediate I-4. The obtained compound was identified by LC-MS. C 26 H 15 BrN 2 : M+1 435.0. 
     Synthesis of Compound 33 
     4.48 g of Compound 33 (yield: 72%) was obtained in the same (or substantially the same) manner as in Synthesis of Compound 2, except that Intermediate I-9 was used instead of Intermediate I-6, and Intermediate A-1 was used instead of 2-chloro-4,6-diphenyl-1,3,5-triazine. The obtained compound was identified by MS/FAB and  1 H NMR. C 45 H 26 N 4  cal. 622.22. found 622.23. 
     Synthesis Example 4: Synthesis of Compound 52 
                         
Synthesis of Intermediate I-10
 
     3.52 g of Intermediate I-10 (yield: 70%) was obtained in the same (or substantially the same) manner as in Synthesis of Intermediate I-4, except that Intermediate A-2 was used instead of 4-bromobenzoyl chloride. The obtained compound was identified by LC-MS. C 30 H 19 BrN 2 O: M+1 503.1. 
     Synthesis of Intermediate I-11 
     3.54 g of Intermediate I-11 (yield: 73%) was obtained in the same (or substantially the same) manner as in Synthesis of Intermediate I-5, except that Intermediate I-10 was used instead of Intermediate I-4. The obtained compound was identified by LC-MS. C 30 H 17 BrN 2 : M+1 485.1. 
     Synthesis of Compound 52 
     3.85 g of Compound 52 (yield: 76%) was obtained in the same (or substantially the same) manner as in Synthesis of Compound 2, except that Intermediate I-11 was used instead of Intermediate I-6, and 4-cyanophenylboronic acid was used instead of 2-chloro-4,6-diphenyl-1,3,5-triazine. The obtained compound was identified by MS/FAB and  1 H NMR. C 37 H 21 N 3  cal. 507.17. found 507.18. 
     Synthesis Example 5: Synthesis of Compound 84 
                         
Synthesis of Intermediate I-12
 
     2.58 g of Intermediate I-12 (yield: 68%) was obtained in the same (or substantially the same) manner as in Synthesis of Intermediate I-2, except that 1,4-dibromo-2-nitrobenzene was used instead of 1-bromo-2-nitrobenzene. The obtained compound was identified by LC-MS. C 19 H 11 BrN 2 O 2 : M+1 379.0. 
     Synthesis of Intermediate I-13 
     3.32 g of Intermediate I-13 (yield: 95%) was obtained in the same (or substantially the same) manner as in Synthesis of Intermediate I-3, except that Intermediate I-12 was used instead of Intermediate I-2. The obtained compound was identified by LC-MS. C 19 H 13 BrN: M+1 349.0. 
     Synthesis of Intermediate I-14 
     3.44 g of Intermediate I-14 (yield: 76%) was obtained in the same (or substantially the same) manner as in Synthesis of Intermediate I-4, except that Intermediate I-13 was used instead of Intermediate I-3, and benzaldehyde was used instead of 4-bromobenzoyl chloride. The obtained compound was identified by LC-MS. C 26 H 17 BrN 2 O: M+1 453.1. 
     Synthesis of Intermediate I-15 
     2.91 g of Intermediate I-15 (yield: 67%) was obtained in the same (or substantially the same) manner as in Synthesis of Intermediate I-5, except that Intermediate I-14 was used instead of Intermediate I-4. The obtained compound was identified by LC-MS. C 26 H 15 BrN 2 : M+1 435.0. 
     Synthesis of Compound 84 
     4.06 g of Compound 84 (yield: 76%) was obtained in the same (or substantially the same) manner as in Synthesis of Compound 15, except that Intermediate I-15 was used instead of Intermediate I-5. The obtained compound was identified by MS/FAB and  1 H NMR. C 38 H 25 N 2 OP cal. 556.17. found 556.18. 
     Synthesis Example 6: Synthesis of Compound 106 
                         
Synthesis of Intermediate I-16
 
     3.42 g of Intermediate I-16 (yield: 71%) was obtained in the same (or substantially the same) manner as in Synthesis of Intermediate I-1, except that Intermediate I-15 was used instead of 10-bromobenzo[h]quinoline. The obtained compound was identified by LC-MS. C 32 H 27 BN 2 O 2 : M+1 483.2. 
     Synthesis of Compound 106 
     4.97 g of Compound 106 (yield: 70%) was obtained in the same (or substantially the same) manner as in Synthesis of Compound 2, except that Intermediate I-16 was used instead of Intermediate I-6, and Intermediate I-9 was used instead of 2-chloro-4,6-diphenyl-1,3,5-triazine. The obtained compound was identified by MS/FAB and  1 H NMR. C 52 H 30 N 4  cal. 710.25. found 710.24. 
     Synthesis Example 7: Synthesis of Compound 125 
     
       
         
         
             
             
         
       
     
     3.80 g of Compound 125 (yield: 60%) was obtained in the same (or substantially the same) manner as in Synthesis of Compound 2, except that Intermediate I-16 was used instead of Intermediate I-6, and Intermediate A-3 was used instead of 2-chloro-4,6-diphenyl-1,3,5-triazine. The obtained compound was identified by MS/FAB and  1 H NMR. C 47 H 27 N 3  cal. 633.22. found 633.21. 
     Methods of synthesizing compounds other than compounds shown in Table 1 should be apparent to those skilled in the art by referring to the synthesis pathways and raw materials described above. 
     
       
         
           
               
               
             
               
                   
                 TABLE 1 
               
             
            
               
                   
                   
               
               
                   
                 MS/FAB 
               
            
           
           
               
               
               
               
            
               
                 Compound 
                   1 H NMR (CDCl 3  , 400 MHz) 
                 found 
                 calc. 
               
               
                   
               
            
           
           
               
               
               
               
            
               
                 2 
                 δ = 8.84-8.82 (dd, 1H), 8.73-8.70 (m, 4H), 8.63-8.60 (m, 
                 587.20 
                 587.21 
               
               
                   
                 2H), 8.49-8.45 (m, 3H), 8.36-8.34 (m, 1H), 8.30-8.28 (m, 
               
               
                   
                 1H), 8.23-8.21 (m, 1H), 7.92-7.88 (m, 2H), 7.76-7.72 (m, 
               
               
                   
                 2H), 7.63-7.53 (m, 5H), 7.49-7.46 (m, 1H), 7.42-7.38 (m, 
               
               
                   
                 2H) 
               
               
                 10 
                 δ = 8.81-8.80 (dd, 1H), 8.49-8.47 (m, 1H), 8.38-8.36 (m, 
                 573.21 
                 573.22 
               
               
                   
                 1H), 8.31-8.23 (m, 4H), 7.89-7.72 (m, 7H), 7.67-7.65 (m, 
               
               
                   
                 1H), 7.57-7.42 (m, 6H), 1.59 (s, 6H) 
               
               
                 15 
                 δ = 8.78-8.76 (dd, 1H), 8.49-8.47 (m, 1H), 8.37-8.35 (m, 
                 556.18 
                 556.17 
               
               
                   
                 1H), 8.31-8.29 (m, 1H), 8.25-8.23 (m, 1H), 8.04-8.00 (m, 
               
               
                   
                 2H), 7.89-7.82 (m, 2H), 7.79-7.74 (m, 3H), 7.70-7.65 (m, 
               
               
                   
                 5H), 7.57-7.40 (m, 8H) 
               
               
                 18 
                 δ = 9.66 (s, 1H), □8.78-8.64 (m, 5H), 8.60-8.56 (m, 3H), 
                 587.20 
                 587.21 
               
               
                   
                 8.51-8.49 (m, 3H), 8.36-8.34 (m, 1H), 8.30-8.28 (m, 1H), 
               
               
                   
                 8.16-8.14 (m, 1H), 7.90-7.86 (m, 1H), 7.74-7.70 (m, 1H), 
               
               
                   
                 7.65-7.53 (m, 6H), 7.42-7.38 (m, 2H) 
               
               
                 27 
                 δ = 9.67 (s, 1H), 8.72-8.70 (m, 1H), 8.61-8.59 (m, 1H), 
                 522.19 
                 522.17 
               
               
                   
                 8.52-8.50 (m, 1H), 8.37-8.35 (m, 1H), 8.32-8.30 (m, 1H), 
               
               
                   
                 8.22-8.15 (m, 3H), 7.95-7.86 (m, 5H), 7.74-7.72 (m, 2H), 
               
               
                   
                 7.66-7.61 (m, 2H), 7.57-7.48 (m, 2H), 7.42-7.31 (m, 2H) 
               
               
                 33 
                 δ = 8.76-8.75 (dd, 1H), 8.41 (t, 1H), 8.34-8.32 (m, 1H), 
                 622.23 
                 622.22 
               
               
                   
                 8.29-8.21 (m, 5H), 7.92-7.83 (m, 5H), 7.76-7.62 (m, 4H), 
               
               
                   
                 7.57-7.47 (m, 6H), 7.43-7.39 (m, 1H), 7.34-7.28 (m, 2H) 
               
               
                 52 
                 δ = 8.77-8.75 (m, 1H), 8.50-8.48 (m, 1H), 8.39-8.37 (m, 
                 507.18 
                 507.17 
               
               
                   
                 1H), 8.31-8.29 (m, 1H), 8.25-8.23 (dd, 1H), 8.11-8.09 
               
               
                   
                 (m, 1H), 8.00-7.82 (m, 4H), 7.76-7.73 (m, 3H), 7.68-7.65 
               
               
                   
                 (m, 1H), 7.57-7.54 (m, 3H), 7.49-7.41 (m, 3H), 7.10-7.06 
               
               
                   
                 (m, 1H) 
               
               
                 63 
                 δ = 9.68 (s, 1H), 8.90-8.88 (m, 1H), 8.84-8.82 (m, 1H), 
                 483.18 
                 483.17 
               
               
                   
                 8.61-8.58 (m, 3H), 8.40-8.38 (m, 1H), 8.32-8.30 (m, 1H), 
               
               
                   
                 8.17-8.12 (m, 3H), 7.94-7.88 (m, 2H), 7.84-7.81 (m, 2H), 
               
               
                   
                 7.74-7.70 (m, 1H), 7.66-7.52 (m, 3H), 7.39-7.36 (m, 1H), 
               
               
                   
                 7.15-7.12 (m, 1H) 
               
               
                 70 
                 δ = 8.81-8.79 (dd, 1H), 8.70-8.68 (m, 2H), 8.50-8.48 (m, 
                 533.20 
                 533.19 
               
               
                   
                 1H), 8.432-8.30 (m, 1H), 8.26-8.23 (m, 3H), 8.04-8.01 
               
               
                   
                 (m, 3H), 7.94-7.90 (m, 1H), 7.84-7.74 (m, 2H), 7.71-7.66 
               
               
                   
                 (m, 3H), 7.57-7.53 (m, 1H), 7.49-7.46 (m, 1H), 7.42-7.37 
               
               
                   
                 (m, 2H), 7.27-7.23 (m, 2H) 
               
               
                 84 
                 δ = 8.78-8.76 (dd, 1H), 8.50-8.45 (m, 3H), 8.42-8.40 (m, 
                 556.18 
                 556.17 
               
               
                   
                 1H), 8.23-8.21 (m, 1H), 7.96-7.89 (m, 3H), 7.84-7.82 (m, 
               
               
                   
                 1H), 7.76-7.68 (m, 6H), 7.65-7.59 (m, 3H), 7.52-7.40 (m, 
               
               
                   
                 7H) 
               
               
                 91 
                 δ = 8.76-8.73 (m, 3H), 8.66-8.64 (m, 2H), 8.48-8.45 (m, 
                 586.21 
                 586.22 
               
               
                   
                 3H), 8.45-8.43 (m, 1H), 8.30-8.24 (m, 3H), 8.07-8.04 (m, 
               
               
                   
                 5H), 7.95-7.87 (m, 4H), 7.66-7.60 (m, 3H), 7.50-7.46 (m, 
               
               
                   
                 2H), 7.32-7.29 (m, 1H) 
               
               
                 106 
                 δ = 8.79-8.77 (dd, 2H), 8.59-8.57 (m, 1H), 8.44-8.42 (m, 
                 710.24 
                 710.25 
               
               
                   
                 1H), 8.40 (t, 1H), 8.37-8.35 (m, 1H), 8.32-8.30 (m, 1H), 
               
               
                   
                 8.28-8.26 (m, 1H), 8.23-8.20 (m, 3H), 8.12-8.10 (m, 1H), 
               
               
                   
                 7.95-7.82 (m, 7H), 7.76-7.71 (m, 4H), 7.66-7.53 (m, 4H), 
               
               
                   
                 7.49-7.44 (m, 3H) 
               
               
                 125 
                 δ = 8.80-8.78 (dd, 1H), 8.59-8.57 (m, 1H), 8.43-8.40 (m, 
                 633.21 
                 633.22 
               
               
                   
                 2H), 8.23-8.20 (m, 2H), 7.95-7.90 (m, 2H), 7.87-7.81 (m, 
               
               
                   
                 5H), 7.79-7.72 (m, 4H), 7.68-7.58 (m, 5H), 7.49-7.46 (m, 
               
               
                   
                 1H), 7.39-7.30 (m, 4H) 
               
               
                   
               
            
           
         
       
     
     Example 1 
     A Corning 15 Ohms per square centimeter (Ω/cm 2 , 1,200 Å) ITO glass substrate was cut to a size of 50 millimeters (mm)×50 mm×0.7 mm, and then, sonicated by using isopropyl alcohol and pure water, for 5 minutes respectively, and cleaned by exposure to ultraviolet rays with ozone so as to use the glass substrate as an anode, and then, the glass substrate was mounted on a vacuum-deposition apparatus. 
     2-TNATA was vacuum-deposited on the glass substrate to form a hole injection layer having a thickness of about 600 Å. Thereafter, 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (a hole transport material, hereinafter referred to as “NPB”) was vacuum-deposited on the hole injection layer to form a hole transport layer having a thickness of about 300 Å. 
     
       
         
         
             
             
         
       
     
     9,10-di-naphthalene-2-yl-anthracene (hereinafter referred to as “ADN”) as a blue fluorescent host and 4,4′-bis[2-(4-(N,N-diphenylamino)phenyl)vinyl]biphenyl (hereinafter referred to as “DPAVBi”) as a blue fluorescent dopant were co-deposited on the hole transport layer in a weight ratio of about 98:2 to form an emission layer having a thickness of about 300 Å. 
     Afterward, Compound 2 was deposited on the emission layer to form an electron transport layer having a thickness of about 300 Å. Then, LiF, an alkali metal halide, was deposited on the electron transport layer to form an electron injection layer having a thickness of about 10 Å. Aluminum (Al) was vacuum-deposited on the electron injection layer to form a cathode having a thickness of about 3,000 Å, thereby forming a LiF/Al electrode to complete the manufacture of an organic light-emitting device. 
     Example 2 
     An organic light-emitting device was manufactured in the same (or substantially the same) manner as in Example 1, except that Compound 15 was used instead of Compound 2 in the formation of an electron transport layer. 
     Example 3 
     An organic light-emitting device was manufactured in the same (or substantially the same) manner as in Example 1, except that Compound 33 was used instead of Compound 2 in the formation of an electron transport layer. 
     Example 4 
     An organic light-emitting device was manufactured in the same (or substantially the same) manner as in Example 1, except that Compound 84 was used instead of Compound 2 in the formation of an electron transport layer. 
     Example 5 
     An organic light-emitting device was manufactured in the same (or substantially the same) manner as in Example 1, except that Compound 106 was used instead of Compound 2 in the formation of an electron transport layer. 
     Example 6 
     An organic light-emitting device was manufactured in the same (or substantially the same) manner as in Example 1, except that Compound 125 was used instead of Compound 2 in the formation of an electron transport layer. 
     Comparative Example 1 
     An organic light-emitting device was manufactured in the same (or substantially the same) manner as in Example 1, except that Alq 3  was used instead of Compound 2 in the formation of an electron transport layer. The organic light-emitting device exhibited blue emission of a driving voltage of about 7.35 V, an emission luminance of about 2,065 cd/m 2 , and a current efficiency of about 4.13 cd/A at a current density of about 50 mA/cm 2 . The half-lifespan of luminance of the organic light-emitting device was about 145 hours at a current density of about 100 mA/cm 2 . 
     
       
         
         
             
             
         
       
     
     The results of measuring the driving voltage (V), current density (mA/cm 2 ), luminance (cd/m 2 ), efficiency (cd/A), emission color, and half-lifespan of the organic light-emitting devices manufactured in Examples 1 to 6 and Comparative Example 1 are shown in Table 2. 
     
       
         
           
               
               
               
               
               
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Electron 
                 Driving 
                 Current 
                   
                   
                   
                 Half lifespan 
               
               
                   
                 transport 
                 voltage 
                 density 
                 Luminance 
                 Efficiency 
                 Emission 
                 (hr @ 
               
               
                   
                 layer 
                 (V) 
                 (mA/cm 2 ) 
                 (cd/m 2 ) 
                 (cd/A) 
                 color 
                 100 mA/cm 2 ) 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Example 1 
                 Compound 2 
                 5.72 
                 50 
                 3,325 
                 6.65 
                 blue 
                 231 hours 
               
               
                 Example 2 
                 Compound 15 
                 6.02 
                 50 
                 3,040 
                 6.08 
                 blue 
                 376 hours 
               
               
                 Example 3 
                 Compound 33 
                 5.97 
                 50 
                 3,210 
                 6.42 
                 blue 
                 335 hours 
               
               
                 Example 4 
                 Compound 84 
                 5.91 
                 50 
                 3,110 
                 6.22 
                 blue 
                 359 hours 
               
               
                 Example 5 
                 Compound 106 
                 5.63 
                 50 
                 3,215 
                 6.43 
                 blue 
                 314 hours 
               
               
                 Example 6 
                 Compound 125 
                 5.55 
                 50 
                 3,190 
                 6.38 
                 blue 
                 321 hours 
               
               
                 Comparative 
                 Alq 3   
                 7.35 
                 50 
                 2,065 
                 4.13 
                 blue 
                 145 hours 
               
               
                 Example 1 
               
               
                   
               
            
           
         
       
     
     As can be seen from the results shown in Table 2, when the compound represented by Formula 1 was used as an electron transport material, driving voltages of the organic light-emitting devices manufactured in Examples 1 to 6 were lower than that of Comparative Example 1 by at least 1 V. Furthermore, the organic light-emitting devices manufactured in Examples 1 to 6 exhibited excellent I-V-L (current-voltage-luminance) characteristics with significant improvement of efficiency and lifespan. Accordingly, it can be seen that the compound represented by Formula 1 according to an example embodiment of the present disclosure may be appropriate for use as an electron transport material. 
     An organic light-emitting device according to embodiments of the present disclosure may have high efficiency, low voltage, high luminance, and a long lifespan. 
     As used herein, the terms “use,” “using,” and “used” may be considered synonymous with the terms “utilize,” “utilizing,” and “utilized,” respectively. 
     In addition, the terms “substantially,” “about,” and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent deviations in measured or calculated values that would be recognized by those of ordinary skill in the art. 
     Also, any numerical range recited herein is intended to include all subranges of the same numerical precision subsumed within the recited range. For example, a range of “1.0 to 10.0” is intended to include all subranges between (and including) the recited minimum value of 1.0 and the recited maximum value of 10.0, that is, having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limitation recited herein is intended to include all lower numerical limitations subsumed therein and any minimum numerical limitation recited in this specification is intended to include all higher numerical limitations subsumed therein. Accordingly, Applicant reserves the right to amend this specification, including the claims, to expressly recite any sub-range subsumed within the ranges expressly recited herein. 
     It should be understood that example embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each example embodiment should typically be considered as available for other similar features or aspects in other example embodiments. 
     While one or more example embodiments have been described with reference to the drawing, 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 of the present disclosure as defined by the following claims and equivalents thereof.