Patent Publication Number: US-2023165137-A1

Title: Light emitting element and amine compound for the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to and the benefit of Korean Patent Application No. 10-2021-0160326, filed on Nov. 19, 2021, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND 
     Embodiments of the present disclosure herein relate to a light emitting element and an amine compound used therein. 
     Recently, the development of an organic electroluminescence display device as an image display device is being actively conducted. The organic electroluminescence display device includes a so-called self-luminescent light emitting element in which holes and electrons injected from a first electrode and a second electrode, respectively, recombine in an emission layer, and thus, a luminescent material of the emission layer emits light to implement display. 
     In the application of a light emitting element to a display device, there is a demand for a light emitting element having high luminous efficiency and a long service life, and development of materials for a light emitting element capable of stably attaining such a characteristic is being continuously researched. 
     SUMMARY 
     Embodiments of the present disclosure provide a light emitting element having excellent service life, efficiency, and brightness and having a decrease in driving voltage. 
     Embodiments of the present disclosure also provide an amine compound which is a material for a light emitting element having characteristics of reduced driving voltage, a long service life, high efficiency, and high brightness. 
     An embodiment of the present disclosure provides a light emitting element including: a first electrode; a second electrode on the first electrode; and at least one functional layer which is between the first electrode and the second electrode and includes an amine compound represented by Formula 1 below: 
     
       
         
         
             
             
         
       
     
     In Formula 1 above, L 1  is a direct linkage, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms, n1 and n2 are each independently an integer of 0 to 3, Ar 1  and Ar 2  are each independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, and Ar 3  and Ar 4  are each independently a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. 
     In Formula 1 above, Ar 3  and Ar 4  are each independently a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted fluorenyl group, a substituted or unsubstituted carbazole group, a substituted or unsubstituted dibenzofuran group, or a substituted or unsubstituted dibenzothiophene group. 
     In an embodiment, in Formula 1 above, Ar 3  and Ar 4  may be each independently represented by any one selected from among A-1 to A-7 below: 
     
       
         
         
             
             
         
       
     
     In A-4 above, R 1  and R 2  are each independently a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or are bonded to an adjacent group to form a ring, and in A-5 above, R 3  is a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms. 
     In an embodiment, Formula 1 above may be represented by Formula 1-1 below: 
     
       
         
         
             
             
         
       
     
     In Formula 1-1 above, R 11  to R 20  are each independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted amine group, a substituted or unsubstituted oxy group, a substituted or unsubstituted thio group, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 10 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or may be bonded to an adjacent group to form a ring. 
     In an embodiment, Formula 1 above may be represented by Formula 1-A1 or Formula 1-A2 below: 
     
       
         
         
             
             
         
       
     
     In Formula 1-A1 and Formula 1-A2 above, L 1 , n1, n2, and Ar 1  to Ar 4  are the same as defined with respect to Formula 1 above. 
     In an embodiment, in Formula 1-A1 and Formula 1-A2 above, L 1  may be a direct linkage or a phenylene group. 
     In an embodiment, Formula 1 above may be represented by Formula 1-B1 or Formula 1-B2 below: 
     
       
         
         
             
             
         
       
     
     In Formula 1-B1 and Formula 1-B2, Ar 11  is a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, and L 1 , Ar 3 , and Ar 4  are the same as defined with respect to Formula 1 above. 
     In an embodiment, Formula 1 above may be represented by Formula 1-C1 or Formula 1-C2 below: 
     
       
         
         
             
             
         
       
     
     In Formula 1-C1 and Formula 1-C2 above, Ar 12  is a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, and L 1 , Ar 3 , and Ar 4  are the same as defined with respect to Formula 1 above. 
     In an embodiment, the at least one functional layer may include an emission layer, a hole transport region between the first electrode and the emission layer, and an electron transport region between the emission layer and the second electrode, and the hole transport region may include the amine compound. 
     In an embodiment, the hole transport region may include a hole injection layer on the first electrode, a hole transport layer on the hole injection layer, and an electron blocking layer on the hole transport layer, and at least one of the hole injection layer, the hole transport layer, or the electron blocking layer may include the amine compound. 
     In an embodiment, the emission layer may include a compound represented by Formula E-1 below: 
     
       
         
         
             
             
         
       
     
     In Formula E-1 above, a1 and a2 are each independently an integer of 0 to 5, and R 31  to R 40  are each independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted silyl group, a substituted or unsubstituted thio group, a substituted or unsubstituted oxy group, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, or are bonded to an adjacent group to form a ring. 
     In an embodiment of the present disclosure, an amine compound is represented by Formula 1 above. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The accompanying drawings are included to provide a further understanding of embodiments of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate example embodiments of the present disclosure and, together with the description, serve to explain principles of the subject matter of the present disclosure. In the drawings: 
         FIG.  1    is a plan view illustrating a display device according to an embodiment of the present disclosure; 
         FIG.  2    is a cross-sectional view illustrating a portion taken along line I-I′ of  FIG.  1   ; 
         FIG.  3    is a cross-sectional view schematically illustrating a light emitting element of an embodiment of the present disclosure; 
         FIG.  4    is a cross-sectional view schematically illustrating a light emitting element of an embodiment of the present disclosure; 
         FIG.  5    is a cross-sectional view schematically illustrating a light emitting element of an embodiment of the present disclosure; 
         FIG.  6    is a cross-sectional view schematically illustrating a light emitting element of an embodiment of the present disclosure; 
         FIG.  7    is a cross-sectional view illustrating a display device according to an embodiment of the present disclosure; 
         FIG.  8    is a cross-sectional view illustrating a display device according to an embodiment of the present disclosure; 
         FIG.  9    is a cross-sectional view illustrating a display device according to an embodiment of the present disclosure; and 
         FIG.  10    is a cross-sectional view illustrating a display device according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The subject matter of the present disclosure may be modified in many alternate forms, and thus, example embodiments will be illustrated in the drawings and described in more detail. It should be understood, however, that it is not intended to limit the present disclosure to the particular forms disclosed, but rather, is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure. 
     In the present specification, when a component (or a region, a layer, a portion, etc.) is referred to as being “on,” “connected to,” or “coupled to” another component, it means that the component may be directly on/connected to/coupled to the other component, or that a third component may be therebetween. 
     Like reference numerals refer to like components throughout. Also, in the drawings, the thickness, the ratio, and the dimensions of components may be exaggerated for an effective description of technical contents. The term “and/or” includes all combinations of one or more of which associated configurations may define. 
     It will be understood that, although the terms “first,” “second,” etc. may be used herein to describe various components, these components should not be limited by these terms. These terms are only used to distinguish one component from another. For example, a first component could be termed a second component, and, similarly, a second component could be termed a first component, without departing from the scope of the present disclosure. As used herein, the singular forms, “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. 
     In addition, terms such as “below,” “under,” “on,” and “above” may be used to describe the relationship between elements illustrated in the figures. The terms are used as a relative concept and are described with reference to the direction indicated in the drawings. 
     It should be understood that the terms “comprise,” or “have” are intended to specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof in the disclosure, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure belongs. In addition, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     Hereinafter, a light emitting element and an amine compound according to embodiments of the present disclosure will be described with reference to the drawings. 
       FIG.  1    is a plan view illustrating an embodiment of a display device DD.  FIG.  2    is a cross-sectional view of the display device DD of the embodiment.  FIG.  2    is a cross-sectional view illustrating a part taken along line I-I′ of  FIG.  1   . 
     The display device DD may include a display panel DP and an optical layer PP on the display panel DP. The display panel DP may include light emitting elements ED- 1 , ED- 2 , and ED- 3 . The display device DD may include a plurality of light emitting elements ED- 1 , ED- 2 , and ED- 3 . The optical layer PP may be on the display panel DP and control reflected light in the display panel DP due to external light. The optical layer PP may include, for example, a polarization layer and/or a color filter layer. Unlike the configuration illustrated in the drawing, the optical layer PP may be omitted from the display device DD of an embodiment. 
     A base substrate BL may be on the optical layer PP. The base substrate BL may be a member which provides a base surface that the optical layer PP is on. The base substrate BL may be a glass substrate, a metal substrate, a plastic substrate, etc. However, embodiments of the present disclosure are not limited thereto, and the base substrate BL may be an inorganic layer, an organic layer, or a composite material layer. In addition, unlike the configuration illustrated, in an embodiment, the base substrate BL may be omitted. 
     The display device DD according to an embodiment may further include a filling layer. The filling layer may be between a display element layer DP-ED and the base substrate BL. The filling layer may be an organic material layer. The filling layer may include at least one of an acrylic-based resin, a silicone-based resin, or an epoxy-based resin. 
     The display panel DP may include a base layer BS, a circuit layer DP-CL provided on the base layer BS, and the display element layer DP-ED. The display element layer DP-ED may include a pixel defining film PDL, the light emitting elements ED- 1 , ED- 2 , and ED- 3  between portions of the pixel defining film PDL, and an encapsulation layer TFE on the light emitting elements ED- 1 , ED- 2 , and ED- 3 . 
     The base layer BS may be a member which provides a base surface that the display element layer DP-ED is on. The base layer BS may be a glass substrate, a metal substrate, a plastic substrate, etc. However, embodiments of the present disclosure are not limited thereto, and the base layer BS may be an inorganic layer, an organic layer, or a composite material layer. 
     In an embodiment, the circuit layer DP-CL is on the base layer BS, and the circuit layer DP-CL may include a plurality of transistors. Each of the transistors may include a control electrode, an input electrode, and an output electrode. For example, the circuit layer DP-CL may include a switching transistor and a driving transistor in order to drive the light emitting elements ED- 1 , ED- 2 , and ED- 3  of the display element layer DP-ED. 
     Each of the light emitting elements ED- 1 , ED- 2 , and ED- 3  may have a structure of a light emitting element ED of an embodiment according to  FIGS.  3  to  6   , which will be further described herein below. Each of the light emitting elements ED- 1 , ED- 2  and ED- 3  may include a first electrode EL 1 , a hole transport region HTR, emission layers EML-R, EML-G and EML-B, an electron transport region ETR, and a second electrode EL 2 . 
       FIG.  2    illustrates an embodiment in which the emission layers EML-R, EML-G, and EML-B of the light emitting elements ED- 1 , ED- 2 , and ED- 3  are in openings OH defined in the pixel defining film PDL, and the hole transport region HTR, the electron transport region ETR, and the second electrode EL 2  are provided as a common layer in the entire light emitting elements ED- 1 , ED- 2 , and ED- 3 . However, embodiments of the present disclosure are not limited thereto, and unlike the configuration illustrated in  FIG.  2   , the hole transport region HTR and the electron transport region ETR in an embodiment may be provided by being patterned inside the opening OH defined in the pixel defining film PDL. For example, the hole transport region HTR, the emission layers EML-R, EML-G, and EML-B, and the electron transport region ETR of the light emitting elements ED- 1 , ED- 2 , and ED- 3  in an embodiment may be provided by being patterned in an inkjet printing method. 
     The encapsulation layer TFE may cover the light emitting elements ED- 1 , ED- 2  and ED- 3 . The encapsulation layer TFE may seal the display element layer DP-ED. The encapsulation layer TFE may be a thin film encapsulation layer. The encapsulation layer TFE may be formed by laminating one layer or a plurality of layers. The encapsulation layer TFE may include at least one insulation layer. The encapsulation layer TFE according to an embodiment may include at least one inorganic film (hereinafter, an encapsulation-inorganic film). The encapsulation layer TFE according to an embodiment may also include at least one organic film (hereinafter, an encapsulation-organic film) and at least one encapsulation-inorganic film. 
     The encapsulation-inorganic film may protect the display element layer DP-ED from moisture/oxygen, and the encapsulation-organic film may protect the display element layer DP-ED from foreign substances such as dust particles. The encapsulation-inorganic film may include silicon nitride, silicon oxynitride, silicon oxide, titanium oxide, aluminum oxide, and/or the like, but embodiments of the present disclosure are not particularly limited thereto. The encapsulation-organic film may include an acrylic-based compound, an epoxy-based compound, or the like. The encapsulation-organic film may include a photopolymerizable organic material, but embodiments of the present disclosure are not particularly limited thereto. 
     The encapsulation layer TFE may be on the second electrode EL 2  and may fill the opening OH. 
     Referring to  FIGS.  1  and  2   , the display device DD may include a non-light emitting region NPXA and light emitting regions PXA-R, PXA-G and PXA-B. The light emitting regions PXA-R, PXA-G and PXA-B may be regions in which light generated by the respective light emitting elements ED- 1 , ED- 2 , and ED- 3  is emitted. The light emitting regions PXA-R, PXA-G, and PXA-B may be spaced apart from each other on a plane. 
     Each of the light emitting regions PXA-R, PXA-G, and PXA-B may be a region divided by the pixel defining film PDL. The non-light emitting regions NPXA may be regions between the adjacent light emitting regions PXA-R, PXA-G, and PXA-B, which correspond to portions of the pixel defining film PDL. In the specification, the light emitting regions PXA-R, PXA-G, and PXA-B may respectively correspond to pixels. The pixel defining film PDL may divide the light emitting elements ED- 1 , ED- 2 , and ED- 3 . The emission layers EML-R, EML-G and EML-B of the light emitting elements ED- 1 , ED- 2 , and ED- 3  may be in openings OH defined in the pixel defining film PDL and spaced apart from each other. 
     The light emitting regions PXA-R, PXA-G and PXA-B may be divided into a plurality of groups according to the color of light generated from the light emitting elements ED- 1 , ED- 2  and ED- 3 . In the display device DD of an embodiment shown in  FIGS.  1  and  2   , three light emitting regions PXA-R, PXA-G, and PXA-B which emit red light, green light, and blue light, respectively are illustrated as example embodiments. For example, the display device DD of an embodiment may include the red light emitting region PXA-R, the green light emitting region PXA-G, and the blue light emitting region PXA-B that are spaced apart from each other. 
     In the display device DD according to an embodiment, the plurality of light emitting elements ED- 1 , ED- 2 , and ED- 3  may emit light beams having wavelengths different from each other. For example, in an embodiment, the display device DD may include a first light emitting element ED- 1  that emits red light, a second light emitting element ED- 2  that emits green light, and a third light emitting element ED- 3  that emits blue light. In some embodiments, the red light emitting region PXA-R, the green light emitting region PXA-G, and the blue light emitting region PXA-B of the display device DD may correspond to the first light emitting element ED- 1 , the second light emitting element ED- 2 , and the third light emitting element ED- 3 , respectively. 
     However, embodiments of the present disclosure are not limited thereto, and the first to third light emitting elements ED- 1 , ED- 2 , and ED- 3  may emit light beams in the same wavelength range or at least one light emitting element may emit a light beam in a wavelength range different from the others. For example, the first to third light emitting elements ED- 1 , ED- 2 , and ED- 3  may all emit blue light. 
     The light emitting regions PXA-R, PXA-G, and PXA-B in the display device DD according to an embodiment may be arranged in a stripe form. Referring to  FIG.  1   , the plurality of red light emitting regions PXA-R, the plurality of green light emitting regions PXA-G, and the plurality of blue light emitting regions PXA-B each may be arranged along a second directional axis DR 2 . In addition, the red light emitting region PXA-R, the green light emitting region PXA-G, and the blue light emitting region PXA-B may be alternately arranged in this order along a first directional axis DR  1 . 
       FIGS.  1  and  2    illustrate that all the light emitting regions PXA-R, PXA-G, and PXA-B have similar area, but embodiments of the present disclosure are not limited thereto. Thus, the light emitting regions PXA-R, PXA-G, and PXA-B may have different areas from each other according to the wavelength range of the emitted light. In this case, the areas of the light emitting regions PXA-R, PXA-G, and PXA-B may mean areas when viewed on a plane defined by the first directional axis DR 1  and the second directional axis DR 2 . 
     An arrangement form of the light emitting regions PXA-R, PXA-G, and PXA-B is not limited to the configuration illustrated in  FIG.  1   , and the order in which the red light emitting region PXA-R, the green light emitting region PXA-G, and the blue light emitting region PXA-B are arranged may be provided in various combinations according to the characteristics of display quality required in the display device DD. For example, the arrangement form of the light emitting regions PXA-R, PXA-G, and PXA-B may be a PENTILE® arrangement structure (e.g., an RGBG matrix, RGBG structure, or RGBG matrix structure) or a Diamond Pixel™ arrangement form. PENTILE® is a duly registered trademark of Samsung Display Co., Ltd. 
     In addition, the areas of the light emitting regions PXA-R, PXA-G, and PXA-B may be different from each other. For example, in an embodiment, the area of the green light emitting region PXA-G may be smaller than that of the blue light emitting region PXA-B, but embodiments of the present disclosure are not limited thereto. 
     Hereinafter,  FIGS.  3  to  6    are cross-sectional views schematically illustrating light emitting elements according to embodiments. Each of the light emitting elements ED according to embodiments may include a first electrode EL 1 , a hole transport region HTR, an emission layer EML, an electron transport region ETR, and a second electrode EL 2  that are sequentially stacked. 
     Compared to  FIG.  3   ,  FIG.  4    illustrates a cross-sectional view of a light emitting element ED of an embodiment, in which a hole transport region HTR includes a hole injection layer HIL and a hole transport layer HTL, and an electron transport region ETR includes an electron injection layer EIL and an electron transport layer ETL. In addition, compared to  FIG.  3   ,  FIG.  5    illustrates a cross-sectional view of a light emitting element ED of an embodiment, in which a hole transport region HTR includes a hole injection layer HIL, a hole transport layer HTL, and an electron blocking layer EBL, and an electron transport region ETR includes an electron injection layer EIL, an electron transport layer ETL, and a hole blocking layer HBL. Compared to  FIG.  4   ,  FIG.  6    illustrates a cross-sectional view of a light emitting element ED of an embodiment including a capping layer CPL on a second electrode EL 2 . 
     In an embodiment, the light emitting element ED may include an amine compound in at least one functional layer between the first electrode EL 1  and the second electrode EL 2 . The at least one functional layer may include a hole transport region HTR, an emission layer EML, and/or an electron transport region ETR. The amine compound may include an amine group directly or indirectly bonded to a pentacyclic fused ring containing an acridine moiety. 
     In the specification, the term “substituted or unsubstituted” may mean unsubstituted or substituted with at least one substituent selected from the group consisting of a deuterium atom, a halogen atom, a cyano group, a nitro group, an amine group, a silyl group, an oxy group, a thio group, a sulfinyl group, a sulfonyl group, a carbonyl group, a boron group, a phosphine oxide group, a phosphine sulfide group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, a hydrocarbon ring group, an aryl group, and a heterocyclic group. In addition, each of the substituents identified above may be substituted or unsubstituted. For example, a biphenyl group may be interpreted as an aryl group or a phenyl group substituted with a phenyl group. 
     In the specification, the phrase “bonded to an adjacent group to form a ring” may indicate that one is bonded to an adjacent group to form a substituted or unsubstituted hydrocarbon ring, or a substituted or unsubstituted heterocycle. The hydrocarbon ring includes an aliphatic hydrocarbon ring and an aromatic hydrocarbon ring. The heterocycle includes an aliphatic heterocycle and an aromatic heterocycle. The hydrocarbon ring and the heterocycle may be monocyclic or polycyclic. In addition, the rings formed by being bonded to each other may be connected to another ring to form a spiro structure. 
     In the specification, the term “adjacent group” may mean a substituent substituted for an atom which is directly linked to an atom substituted with a corresponding substituent, another substituent substituted for an atom which is substituted with a corresponding substituent, or a substituent sterically positioned at the nearest position to a corresponding substituent. For example, two methyl groups in 1,2-dimethylbenzene may be interpreted as “adjacent groups” to each other and two ethyl groups in 1,1-diethylcyclopentane may be interpreted as “adjacent groups” to each other. In addition, two methyl groups in 4,5-dimethylphenanthrene may be interpreted as “adjacent groups” to each other. 
     In the specification, examples of the halogen atom may include a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom. 
     In the specification, the alkyl group may be a linear, branched or cyclic type (e.g., a linear alkyl group, a branched alkyl group, or a cyclic alkyl group). The number of carbons in the alkyl group is 1 to 50, 1 to 30, 1 to 20, 1 to 10, or 1 to 6. Examples of the alkyl group may include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an s-butyl group, a t-butyl group, an i-butyl group, a 2-ethylbutyl group, a 3,3-dimethylbutyl group, an n-pentyl group, an i-pentyl group, a neopentyl group, a t-pentyl group, a cyclopentyl group, a 1-methylpentyl group, a 3-methylpentyl group, a 2-ethylpentyl group, a 4-methyl-2-pentyl group, an n-hexyl group, a 1-methylhexyl group, a 2-ethylhexyl group, a 2-butylhexyl group, a cyclohexyl group, a 4-methylcyclohexyl group, a 4-t-butylcyclohexyl group, an n-heptyl group, a 1-methylheptyl group, a 2,2-dimethylheptyl group, a 2-ethylheptyl group, a 2-butylheptyl group, an n-octyl group, a t-octyl group, a 2-ethyloctyl group, a 2-butyloctyl group, a 2-hexyloctyl group, a 3,7-dimethyloctyl group, a cyclooctyl group, an n-nonyl group, an n-decyl group, an adamantyl group, a 2-ethyldecyl group, a 2-butyldecyl group, a 2-hexyldecyl group, a 2-octyldecyl group, an n-undecyl group, an n-dodecyl group, a 2-ethyldodecyl group, a 2-butyldodecyl group, a 2-hexyldocecyl group, a 2-octyldodecyl group, an n-tridecyl group, an n-tetradecyl group, an n-pentadecyl group, an n-hexadecyl group, a 2-ethylhexadecyl group, a 2-butylhexadecyl group, a 2-hexylhexadecyl group, a 2-octylhexadecyl group, an n-heptadecyl group, an n-octadecyl group, an n-nonadecyl group, an n-eicosyl group, a 2-ethyleicosyl group, a 2-butyleicosyl group, a 2-hexyleicosyl group, a 2-octyleicosyl group, an n-henicosyl group, an n-docosyl group, an n-tricosyl group, an n-tetracosyl group, an n-pentacosyl group, an n-hexacosyl group, an n-heptacosyl group, an n-octacosyl group, an n-nonacosyl group, an n-triacontyl group, etc., but embodiments of the present disclosure are not limited thereto. 
     In the specification, an alkenyl group means a hydrocarbon group including at least one carbon double bond at a main chain (e.g., in the middle) or at a terminal end of an alkyl group having 2 or more carbon atoms. The alkenyl group may be linear or branched. The carbon number is not specifically limited, but is 2 to 30, 2 to 20 or 2 to 10. Examples of the alkenyl group include a vinyl group, a 1-butenyl group, a 1-pentenyl group, a 1,3-butadienyl aryl group, a styrenyl group, a styrylvinyl group, etc., without limitation. 
     The hydrocarbon ring group herein means any functional group or substituent derived from an aliphatic hydrocarbon ring. The hydrocarbon ring group may be a saturated hydrocarbon ring group having 5 to 20 ring-forming carbon atoms. 
     In the specification, an aryl group means any functional group or substituent derived from an aromatic hydrocarbon ring. The aryl group may be a monocyclic aryl group or a polycyclic aryl group. The number of ring-forming carbon atoms in the aryl group may be 6 to 30, 6 to 20, or 6 to 15. Examples of the aryl group may include a phenyl group, a naphthyl group, a fluorenyl group, an anthracenyl group, a phenanthryl group, a biphenyl group, a terphenyl group, a quaterphenyl group, a quinquephenyl group, a sexiphenyl group, a triphenylenyl group, a pyrenyl group, a benzofluoranthenyl group, a chrysenyl group, etc., but embodiments of the present disclosure are not limited thereto. 
     In the specification, the fluorenyl group may be substituted, and two substituents may be bonded to each other to form a spiro structure. Examples of cases where the fluorenyl group is substituted are as follows. However, embodiments of the present disclosure are not limited thereto. 
     
       
         
         
             
             
         
       
     
     The term “heterocyclic group,” as used herein, means any functional group or substituent derived from a ring including at least one of B, O, N, P, Si, or Se as a heteroatom. The heterocyclic group includes an aliphatic heterocyclic group and an aromatic heterocyclic group. The aromatic heterocyclic group may be a heteroaryl group. The aliphatic heterocycle and the aromatic heterocycle may be monocyclic or polycyclic. If the heterocyclic group includes two or more heteroatoms, the two or more heteroatoms may be the same as or different from each other. The heterocyclic group may be a monocyclic heterocyclic group or a polycyclic heterocyclic group and has the concept including a heteroaryl group. The number of ring-forming carbon atoms in the heterocyclic group may be 2 to 30, 2 to 20, or 2 to 10. 
     In the specification, the heteroaryl group may include at least one of B, O, N, P, Si, or S as a heteroatom. When the heteroaryl group contains two or more hetero atoms, the two or more hetero atoms may be the same as or different from each other. The heteroaryl group may be a monocyclic heteroaryl group or polycyclic heteroaryl group. The number of ring-forming carbon atoms in the heteroaryl group may be 2 to 30, 2 to 20, or 2 to 10. Examples of the heteroaryl group may include a thiophene group, a furan group, a pyrrole group, an imidazole group, a pyridine group, a bipyridine group, a pyrimidine group, a triazine group, a triazole group, an acridyl group, a pyridazine group, a pyrazinyl group, a quinoline group, a quinazoline group, a quinoxaline group, a phenoxazine group, a phthalazine group, a pyrido pyrimidine group, a pyrido pyrazine group, a pyrazino pyrazine group, an isoquinoline group, an indole group, a carbazole group, an N-arylcarbazole group, an N-heteroarylcarbazole group, an N-alkylcarbazole group, a benzoxazole group, a benzoimidazole group, a benzothiazole group, a benzocarbazole group, a benzothiophene group, a dibenzothiophene group, a thienothiophene group, a benzofuran group, a phenanthroline group, a thiazole group, an isoxazole group, an oxazole group, an oxadiazole group, a thiadiazole group, a phenothiazine group, a dibenzosilole group, a dibenzofuran group, etc., but embodiments of the present disclosure are not limited thereto. 
     In the specification, the above description of the aryl group may be applied to an arylene group except that the arylene group is a divalent group. The above description of the heteroaryl group may be applied to a heteroarylene group except that the heteroarylene group is a divalent group. 
     In the specification, a silyl group includes an alkylsilyl group and an arylsilyl group. Examples of the silyl group may include a trimethylsilyl group, a triethylsilyl group, a t-butyldimethylsilyl group, an ethyldimethylsilyl group, a propyldimethylsilyl group, a triphenylsilyl group, a diphenylsilyl group, a phenylsilyl group, etc., but embodiments of the present disclosure are not limited thereto. 
     In the specification, a thio group may include an alkylthio group and an arylthio group. The thio group may have a sulfur atom that is bonded to the alkyl group or the aryl group as defined above. Examples of the thio group may include a methylthio group, an ethylthio group, a propylthio group, a pentylthio group, a hexylthio group, an octylthio group, a dodecylthio group, a cyclopentylthio group, a cyclohexylthio group, a phenylthio group, a naphthylthio group, etc., but embodiments of the present disclosure are not limited thereto. 
     In the specification, an oxy group may have an oxygen atom that is bonded to the alkyl group or the aryl group as defined above. The oxy group may include an alkoxy group and an aryl oxy group. The alkoxy group may be a linear chain, a branched chain or a ring chain. The number of carbon atoms in the alkoxy group is not specifically limited, but may be, for example, 1 to 20 or 1 to 10. Examples of the oxy group include methoxy, ethoxy, n-propoxy, isopropoxy, butoxy, pentyloxy, hexyloxy, octyloxy, nonyloxy, decyloxy, benzyloxy, etc., but embodiments of the present disclosure are not limited thereto. 
     In the specification, a boryl group may have a boron atom that is bonded to the alkyl group or the aryl group as defined above. The boryl group includes an alkyl boryl group and an aryl boryl group. Examples of the boryl group may include a dimethylboryl group, a diethylboryl group, a t-butylmethylboryl group, a diphenylboryl group, a phenylboryl group, etc., but embodiments of the present disclosure are not limited thereto. 
     In the specification, an amine group may include —NH 2 , an alkyl amine group, and an aryl amine group. The number of carbon atoms in the amine group is not specifically limited, but may be 1 to 30. Examples of the amine group may include a methylamine group, a dimethylamine group, a phenylamine group, a diphenylamine group, a naphthylamine group, a 9-methyl-anthracenylamine group, a triphenylamine group, etc., but embodiments of the present disclosure are not limited thereto. 
     In the specification, the alkyl group among an alkylthio group, an alkylsulfoxy group, an alkyl oxy group, an alkyl amino group, an alkyl boron group, an alkyl silyl group, and an alkyl amine group is the same as the examples of the alkyl group described above. 
     In the specification, the aryl group among an aryloxy group, an arylthio group, an arylsulfoxy group, an arylamino group, an arylboron group, an arylsilyl group, an arylamine group is the same as the examples of the aryl group described above. 
     In the specification, a direct linkage may be a single bond (e.g., a single covalent bond). In the specification, 
     
       
         
         
             
             
         
       
     
     and 
     
       
         
         
             
             
         
       
     
     mean a position to be linked. 
     The amine compound of an embodiment may be represented by Formula 1 below. The light emitting element ED may include an amine compound represented by Formula 1 below: 
     
       
         
         
             
             
         
       
     
     In Formula 1, L 1  may be a direct linkage, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms. When L 1  is a direct linkage, the amine group may be directly bonded to the pentacyclic fused ring containing an acridine moiety. When L 1  is an arylene group or heteroarylene group, the amine group may be indirectly bonded to the pentacyclic fused ring containing an acridine moiety. For example, L 1  may be a phenyl group, a divalent naphthyl group, a divalent fluorenyl group, a divalent spiro fluorenyl group, a divalent phenanthrenyl group, a divalent dibenzofuranyl group, or a divalent dibenzothiophene group. When L 1  is a phenylene group, the amine group and the pentacyclic fused ring may be bonded at the para-position of the phenylene group. When L 1  is a phenylene group, L 1  may be represented by L-1 below: 
     
       
         
         
             
             
         
       
     
     In Formula 1, n1 and n2 may be each independently an integer of 0 to 3. When n1 is an integer of 2 or more, a plurality of Ar 1 &#39;s may be the same as each other or at least one may be different from the others. When n2 is an integer of 2 or more, a plurality of Ar 2 &#39;s may be the same as each other or at least one may be different from the others. 
     Ar 1  and Ar 2  may be each independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. For example, n1 may be 1, n2 may be 0, and Ar 1  may be a substituted or unsubstituted phenyl group. In some embodiments, n1 may be 0, n2 may be 1, and Ar 1  may be a substituted or unsubstituted phenyl group. 
     Ar 3  and Ar 4  may be each independently a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. For example, Ar 3  and Ar 4  may be each independently a heteroaryl group containing N, O, or S as a ring-forming atom. In some embodiments, Ar 3  and Ar 4  may be each independently a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted fluorenyl group, a substituted or unsubstituted carbazole group, a substituted or unsubstituted dibenzofuran group, or a substituted or unsubstituted dibenzothiophene group. 
     In an embodiment, Ar 3  and Ar 4  may be each independently represented by any one selected from among A-1 to A-7 below. A-1 represents an unsubstituted phenyl group, and A-2 represents an unsubstituted biphenyl group. A-3 represents an unsubstituted naphthyl group, and A-4 represents a substituted or unsubstituted fluorenyl group. A-5 represents a substituted carbazole group, A-6 represents an unsubstituted dibenzofuran group, and A-7 represents an unsubstituted dibenzothiophene group. 
     
       
         
         
             
             
         
       
     
     In A-4, R 1  and R 2  may be each independently a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or may be bonded to an adjacent group to form a ring. For example, each of R 1  and R 2  may be a substituted or unsubstituted phenyl group, and R 1  and R 2  may be bonded to form a spiro fluorenyl group. In some embodiments, R 1  and R 2  may be each independently a methyl group or a phenyl group. 
     In A-5, R 3  may be a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms. For example, R 3  may be a substituted or unsubstituted phenyl group. 
     In some embodiments, A-2 may be represented by any one selected from among A-21 to A-23 below, and A-21 to A-23 have a different position at which an amine group is bonded. A-3 may be represented by A-31 or A-32 below, and A-31 and A-32 have a different position at which an amine group is bonded. A-4 may be represented by any one selected from among A-41 to A-43 below, and A-41 to A-43 represent the case where R 1  and R 2  are methyl groups or phenyl groups. For A-43, R 1  and R 2  are phenyl groups, and R 1  and R 2  are bonded to form a spiro fluorenyl group. 
     
       
         
         
             
             
         
       
     
     In addition, A-5 may be represented by A-51 or A-52 below, and A-51 and A-52 have a different position at which an amine group is bonded. A-51 and A-52 represent the case where R 3  is an unsubstituted phenyl group. A-6 may be represented by any one selected from among A-61 to A-64 below, and A-61 to A-64 have a different position at which an amine group is bonded. A-7 may be represented by any one selected from among A-71 to A-74 below, and A-71 to A-74 have a different position at which an amine group is bonded. 
     
       
         
         
             
             
         
       
     
     In an embodiment, Formula 1 may be represented by Formula 1-1 below: Formula 1-1 represents the case where Ar 3  and Ar 4  are each independently a substituted or unsubstituted phenyl group in Formula 1. 
     
       
         
         
             
             
         
       
     
     In Formula 1-1, R 11  to R 20  are each independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted amine group, a substituted or unsubstituted oxy group, a substituted or unsubstituted thio group, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 10 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or may be bonded to an adjacent group to form a ring. For example, any one selected from among R 11  to R 15  may be an unsubstituted phenyl group. 
     In Formula 1-1, R 13  and R 14  may be vinyl groups, and R 13  and R 14  may be bonded to form a naphthyl group. R 13  may be an aryloxy group, and R 13  and R 14  may be bonded to form a dibenzofuran group. R 13  may be an arylthio group, and R 13  and R 14  may be bonded to form a dibenzothiophene group. R 17  may be an isopropyl group, R 18  may be a phenyl group, and R 17  and R 18  may be bonded to form a dimethylfluorenyl group. R 18  may be a phenyl group, R 19  may be an arylamine group, and R 18  and R 19  may be bonded to form a carbazole group. However, this is an example, and embodiments of the present disclosure are not limited thereto. 
     Formula 1 may be represented by Formula 1-A1 or Formula 1-A2 below. Formula 1-A1 and Formula 1-A2 represent examples of the bonding position of L 1  in Formula 1. 
     
       
         
         
             
             
         
       
     
     In Formula 1-A1 and Formula 1-A2, the same as described with respect to Formula 1 may be applied to L 1 , n1, n2, and Ar 1  to Ar 4 . For example, in Formula 1-A1 and Formula 1-A2, L 1  may be a direct linkage or a phenylene group. 
     Formula 1 may be represented by Formula 1-B1 or Formula 1-B2. Formula 1-B1 and Formula 1-B2 represent examples of the position and kind of Ar 1  when n1 is 1 in Formula 1. 
     
       
         
         
             
             
         
       
     
     In Formula 1-B1 and Formula 1-B2, the same as described with respect to Formula 1 may be applied to L 1 , Ar 3 , and Ar 4 . Ar 11  may be a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms. Ar 11  may correspond to Ar 1  in Formula 1. For example, Ar 11  may be a substituted or unsubstituted phenyl group. 
     Formula 1-B1 may be represented by Formula 1-B11 below, and Formula 1-B2 may be represented by Formula 1-B21 below. Formula 1-B11 represent examples of the bonding position of L 1  in Formula 1-B1. Formula 1-B21 represent examples of the bonding position of L 1  in Formula 1-B2. 
     
       
         
         
             
             
         
       
     
     In Formula 1-B11, the same as described with respect to Formula 1-B1 may be applied to Ar 11 , L 1 , Ar 3 , and Ar 4 . In Formula 1-B21, the same as described with respect to Formula 1-B2 may be applied to Ar 11 , L 1 , Ar 3 , and Ar 4.    
     Formula 1 may be represented by Formula 1-C1 or Formula 1-C2 below. Formula 1-C1 and Formula 1-C2 represent examples of the position and kind of Are when n2 is 1 in Formula 1. 
     
       
         
         
             
             
         
       
     
     In Formula 1-C1 and in Formula 1-C2, Ar 12  may be a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms. For example, Ar 12  may be a substituted or unsubstituted phenyl group. In Formula 1-C1 and Formula 1-C2, the same as described with respect to Formula 1 may be applied to L 1 , Ar 3 , and Ar 4.    
     Formula 1-C1 may be represented by Formula 1-C11 below, and Formula 1-C2 may be represented by Formula 1-C21 below. Formula 1-C11 represent examples of the bonding position of L 1  in Formula 1-C1. Formula 1-C21 represent examples of the bonding position of L 1  in Formula 1-C2. 
     
       
         
         
             
             
         
       
     
     In Formula 1-C11, the same as described with respect to Formula 1-C1 may be applied to Ar 12 , L 1 , Ar 3 , and Ar 4 . In Formula 1-C21, the same as described with respect to Formula 1-C2 may be applied to Ar 12 , L 1 , Ar 3 , and Ar 4.    
     The amine compound of an embodiment may be represented by any one selected from among compounds in Compound Group 1 below. The light emitting element ED of an embodiment may include any one selected from among the compounds of Compound Group 1 below: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     The amine compound of an embodiment may have an amine group is bonded to a pentacyclic fused ring containing an acridine moiety. The amine compound may include a structure represented by Formula Z1 below: 
     
       
         
         
             
             
         
       
     
     In Formula Z1, W1 to W5 are expressed to refer to ring groups that form the pentacyclic fused ring. In Formula Z1, the same as described with respect to Formula 1 may be applied to L 1 , Ar 3 , and Ar 4 . In Formula Z1, a fused ring composed of ring groups of W1 to W3 may correspond to the acridine moiety. 
     The amine compound of an embodiment may include the pentacyclic fused ring containing a nitrogen atom as a ring-forming atom, thereby exhibiting a high glass-transition temperature (Tg). The amine compound may have different kinds of Ar 3  and Ar 4 , which are substituents of the amine group, thereby changing a highest occupied molecular orbital (HOMO) energy level of the amine compound. Accordingly, the amine compound may exhibit an improvement in hole transport properties. 
     The light emitting element ED may include the amine compound of an embodiment in the hole transport region HTR. The light emitting element ED including the amine compound of an embodiment may have an improvement in exciton generation efficiency in the emission layer EML. Therefore, the light emitting element ED including the amine compound of an embodiment may exhibit characteristics in which the driving voltage is reduced, and the brightness and efficiency are improved. In addition, the light emitting element including the amine compound of an embodiment may exhibit a long service life characteristic. 
     Referring to  FIGS.  3  to  6    again, the first electrode EL 1  has conductivity (e.g., electrical conductivity). The first electrode EL 1  may be formed of a metal material, a metal alloy, and/or a conductive compound. The first electrode EL 1  may be an anode or a cathode. However, embodiments of the present disclosure are not limited thereto. In addition, the first electrode EL 1  may be a pixel electrode. The first electrode EL 1  may be a transmissive electrode, a transflective electrode, or a reflective electrode. The first electrode EL 1  may include at least one selected from among Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF, Mo, Ti, W, In, Sn, Zn, a compound of two or more thereof, a mixture of two or more thereof, and an oxide thereof. 
     When the first electrode EL 1  is a transmissive electrode, the first electrode EL 1  may include a transparent metal oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), and indium tin zinc oxide (ITZO). If the first electrode EL 1  is a transflective electrode or a reflective electrode, the first electrode EL 1  may include Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF/Ca (a stacked structure of LiF and Ca), LiF/Al (a stacked structure of LiF and Al), Mo, Ti, W, or a compound or mixture thereof (e.g., a mixture of Ag and Mg). In some embodiments, the first electrode EL 1  may have a multilayer structure including a reflective film or a transflective film formed of the above-described materials, and a transparent conductive film formed of ITO, IZO, ZnO, ITZO, etc. For example, the first electrode EL 1  may have a three-layer structure of ITO/Ag/ITO, but embodiments of the present disclosure are not limited thereto. In some embodiments, the first electrode EL 1  may include the above-described metal materials, combinations of at least two metal materials of the above-described metal materials, oxides of the above-described metal materials, and/or the like. The thickness of the first electrode EL 1  may be from about 700 Å to about 10,000 Å. For example, the thickness of the first electrode EL 1  may be from about 1,000 Å to about 3,000 Å. 
     The hole transport region HTR is provided on the first electrode EL 1 . The thickness of the hole transport region HTR may be, for example, from about 50 Å to about 15,000 Å. 
     The hole transport region HTR may include at least one of a hole injection layer HIL, a hole transport layer HTL, a buffer layer or an emission-auxiliary layer, or an electron blocking layer EBL. As described above, the hole transport region HTR may include the amine compound of an embodiment. At least one of the hole injection layer HIL, the hole transport layer HTL, or the electron blocking layer EBL may include the amine compound of an embodiment. 
     The hole transport region HTR may be formed using various suitable methods such as a vacuum deposition method, a spin coating method, a cast method, a Langmuir-Blodgett (LB) method, an inkjet printing method, a laser printing method, and/or a laser induced thermal imaging (LITI) method. The hole transport region HTR may have a single layer formed of a single material, a single layer formed of a plurality of different materials, or a multilayer structure including a plurality of layers formed of a plurality of different materials. 
     For example, the hole transport region HTR may have a single layer structure of the hole injection layer HIL or the hole transport layer HTL, or may have a single layer structure formed of a hole injection material and a hole transport material. In addition, the hole transport region HTR may have a single layer structure formed of a plurality of different materials, or a structure in which a hole injection layer HIL/hole transport layer HTL, a hole injection layer HIL/hole transport layer HTL/buffer layer, a hole injection layer HIL/buffer layer, a hole transport layer HTL/buffer layer, or a hole injection layer HIL/hole transport layer HTL/electron blocking layer EBL are stacked in order from the first electrode EL 1 , but embodiments of the present disclosure are not limited thereto. 
     The hole transport region HTR may further include compounds which will be further described below. The hole transport region HTR may include a compound represented by Formula H-1 below: 
     
       
         
         
             
             
         
       
     
     In Formula H-1 above, L 1  and L 2  may be each independently a direct linkage, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms. In Formula H-1, a and b may be each independently an integer of 0 to 10. When a or b is an integer of 2 or greater, a plurality of L 1 &#39;s and L 2 &#39;s may be each independently a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms. 
     In Formula H-1, Ar 51  and Ar 52  may be each independently a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. In addition, in Formula H-1, Ar 53  may be a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms. 
     The compound represented by Formula H-1 may be a monoamine compound. In some embodiments, the compound represented by Formula H-1 may be a diamine compound in which at least one among Ar51 to Ar53 includes the amine group as a substituent. In addition, the compound represented by Formula H-1 may be a carbazole-based compound containing a substituted or unsubstituted carbazole group in at least one of Ar 51  or Ar 52 , or a fluorene-based compound containing a substituted or unsubstituted fluorene group in at least one of Ar 51  or Ar 52 . 
     The compound represented by Formula H-1 may be represented by any one selected from among the compounds of Compound Group H below. However, the compounds listed in Compound Group H below are examples, and the compounds represented by Formula H-1 are not limited to those represented by Compound Group H below: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     The hole transport region HTR may further include a phthalocyanine compound such as copper phthalocyanine; N 1 ,N 1 ′-([1,1′-biphenyl]-4,4′-diyl)bis(N 1 -phenyl-N 4 ,N 4 -di-m-tolylbenzene-1,4-diamine) (DNTPD), 4,4′,4″-[tris(3-methylphenyl)phenylamino] triphenylamine (m-MTDATA), 4,4′,4″-Tris(N,N-diphenylamino)triphenylamine (TDATA), 4,4′,4″-tris[N(2-naphthyl)-N-phenylamino]-triphenylamine (2-TNATA), poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS), polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA), polyaniline/camphor sulfonic acid (PANI/CSA), polyaniline/poly(4-styrenesulfonate) (PANI/PSS), N,N′-di(naphthalene-l-yl)-N,N′-diphenyl-benzidine (NPB), triphenylamine-containing polyetherketone (TPAPEK), 4-isopropyl-4′-methyldiphenyliodonium [tetrakis(pentafluorophenyl)borate], dipyrazino[2,3-f: 2′,3′-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HATCN), and/or the like. 
     In addition, the hole transport region HTR may include carbazole derivatives such as N-phenyl carbazole and polyvinyl carbazole, fluorene derivatives, N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1-biphenyl]-4,4′-diamine (TPD), triphenylamine derivatives such as 4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA), N,N′-di(naphthalene-l-yl)-N,N′-diphenyl-benzidine (NPB), 4,4′-cyclohexylidene bis[N,N-bis(4-methylphenyl)benzenamine] (TAPC), 4,4′-bis[N,N′-(3-tolyl)amino]-3,3′-dimethylbiphenyl (HMTPD), 9-(4-tert-butylphenyl)-3,6-bis(triphenylsilyl)-9H-carbazole (CzSi), 9-phenyl-9H-3,9′-bicarbazole (CCP), 1,3-bis(N-carbazolyl)benzene (mCP), 1,3-bis(1,8-dimethyl-9H-carbazol-9-yl)benzene (mDCP), etc. The hole transport region HTR may include the above-described compounds of the hole transport region in at least one of a hole injection layer HIL, a hole transport layer HTL, or an electron blocking layer EBL. 
     The thickness of the hole transport region HTR may be from about 100 Å to about 10,000 Å, for example, from about 100 Å to about 5,000 Å. When the hole transport region HTR includes the hole injection layer HIL, the hole injection layer HIL may have, for example, a thickness of about 30 Å to about 1,000 Å. When the hole transport region HTR includes the hole transport layer HTL, the hole transport layer HTL may have a thickness of about 30 Å to about 1,000 Å. For example, when the hole transport region HTR includes the electron blocking layer EBL, the electron blocking layer EBL may have a thickness of about 10 Å to about 1,000 Å. If the thicknesses of the hole transport region HTR, the hole injection layer HIL, the hole transport layer HTL and the electron blocking layer EBL satisfy the above-described ranges, suitable or satisfactory hole transport properties may be achieved without a substantial increase in driving voltage. 
     The hole transport region HTR may further include a charge generating material to increase conductivity (e.g., electrical conductivity) in addition to the above-described materials. The charge generating material may be dispersed uniformly or non-uniformly in the hole transport region HTR. The charge generating material may be, for example, a p-dopant. The p-dopant may include at least one of a halogenated metal compound, a quinone derivative, a metal oxide, or a cyano group-containing compound, but embodiments of the present disclosure are not limited thereto. For example, the p-dopant may include a metal halide compound such as CuI and RbI, a quinone derivative such as tetracyanoquinodimethane (TCNQ) and/or 2,3,5,6-tetrafluoro-7,7′8,8-tetracyanoquinodimethane (F4-TCNQ), a metal oxide such as tungsten oxide and/or molybdenum oxide, a cyano group-containing compound such as dipyrazino[2,3-f: 2′,3′-h] quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HATCN), 4-[[2,3-bis[cyano-(4-cyano-2,3,5,6-tetrafluorophenyl)methylidene]cyclopropylidene]-cyanomethyl]-2,3,5,6-tetrafluorobenzonitrile (NDP9), etc., but embodiments of the present disclosure are not limited thereto. 
     As described above, the hole transport region HTR may further include at least one of the buffer layer or the electron blocking layer EBL in addition to the hole injection layer HIL and the hole transport layer HTL. The buffer layer may compensate for a resonance distance according to the wavelength of light emitted from the emission layer EML and may thus increase light emission efficiency. A material that may be contained in the hole transport region HTR may be used as a material to be contained in the buffer layer. The electron blocking layer EBL is a layer that serves to prevent or reduce injection of electrons from the electron transport region ETR to the hole transport region HTR. 
     The emission layer EML is provided on the hole transport region HTR. The emission layer EML may have a thickness of, for example, about 100 Å to about 1,000 Å or about 100 Å to about 300 Å. The emission layer EML may have a single layer formed of a single material, a single layer formed of a plurality of different materials, or a multilayer structure having a plurality of layers formed of a plurality of different materials. 
     In the light emitting element ED of an embodiment, the emission layer EML may include an anthracene derivative, a pyrene derivative, a fluoranthene derivative, a chrysene derivative, a dehydrobenzanthracene derivative, and/or a triphenylene derivative. In some embodiments, the emission layer EML may include the anthracene derivative and/or the pyrene derivative. 
     In the light emitting elements ED of embodiments illustrated in  FIGS.  3  to  6   , the emission layer EML may include a host and a dopant. For example, the emission layer EML may include a single host and a single dopant. In some embodiments, the emission layer EML may include at least two hosts, a sensitizer, and a dopant. In some embodiments, the emission layer EML may include a hole transport host and an electron transport host. The emission layer EML may include a phosphorescent sensitizer or a thermally activated delayed fluorescence (TADF) sensitizer as a sensitizer. When the emission layer EML includes a hole transport host, an electron transport host, a sensitizer, and a dopant, the hole transport host and the electron transport host may form an exciplex, and the energy may be transferred from the exciplex to the sensitizer and from the sensitizer to the dopant, and thus, light may be emitted. However, this is an example, and materials included in the emission layer EML are not limited thereto. 
     The emission layer EML may include a compound represented by Formula E-1 below. The compound represented by Formula E-1 below may be used as a fluorescent host material. 
     
       
         
         
             
             
         
       
     
     In Formula E-1, a1 and a2 may be each independently an integer of 0 to 5. When a1 is an integer of 2 or more, a plurality of R 39 &#39;s may be the same as each other or at least one may be different from the others. When a2 is an integer of 2 or more, a plurality of R 40 &#39;s may be the same as each other or at least one may be different from the others. 
     R 31  to R 40  may be each independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted silyl group, a substituted or unsubstituted thio group, a substituted or unsubstituted oxy group, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, or may be bonded to an adjacent group to form a ring. For example, R 31  to R 40  may be bonded to an adjacent group to form a saturated hydrocarbon ring or an unsaturated hydrocarbon ring, a saturated heterocycle, or an unsaturated heterocycle. Formula E-1 may be represented by any one selected from among Compound E1 to Compound E19 below: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     In an embodiment, the emission layer EML may include a compound represented by Formula E-2a or Formula E-2b below. The compound represented by Formula E-2a or Formula E-2b below may be used as a phosphorescent host material. 
     
       
         
         
             
             
         
       
     
     In Formula E-2a, and a may be an integer of 0 to 10, L a  may be a direct linkage, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms. When a is an integer of 2 or more, a plurality of L a &#39;s may be each independently a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms. 
     In addition, in Formula E-2a, A 1  to A 5  may be each independently N or CR i . R a  to R i  may be each independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted amine group, a substituted or unsubstituted thio group, a substituted or unsubstituted oxy group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, or may be bonded to an adjacent group to form a ring. R a  to R i  may be bonded to an adjacent group to form a hydrocarbon ring or a heterocycle containing N, O, S, etc. as a ring-forming atom. 
     In Formula E-2a, two or three selected from among A 1  to A 5  may be N, and the rest may be CR i . 
     
       
         
         
             
             
         
       
     
     In Formula E-2b, Cbz1 and Cbz2 may be each independently an unsubstituted carbazole group, or a carbazole group substituted with an aryl group having 6 to 30 ring-forming carbon atoms. L b  is a direct linkage, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms. In Formula E-2b, b is an integer of 0 to 10, and when b is an integer of 2 or more, a plurality of L b &#39;s may be each independently a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms. 
     The compound represented by Formula E-2a or Formula E-2b may be represented by any one selected from among the compounds of Compound Group E-2 below. However, the compounds listed in Compound Group E-2 below are examples, and the compound represented by Formula E-2a or Formula E-2b is not limited to those represented in Compound Group E-2 below. 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     The emission layer EML may further include any suitable material generally used in the art as a host material. For example, the emission layer EML may include, as a host material, at least one of bis(4-(9H-carbazol-9-yl)phenyl)diphenylsilane (BCPDS), (4-(1-(4-(diphenylamino)phenyl)cyclohexyl)phenyl)diphenyl-phosphine oxide (POPCPA), bis[2-(diphenylphosphino)phenyl]ether oxide (DPEPO), 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP), 1,3-bis(carbazol-9-yl)benzene (mCP), 2,8-bis(diphenylphosphoryl)dibenzo[b,d]furan (PPF), 4,4′,4″-tris(carbazol-9-yl)-triphenylamine (TCTA), or 1,3,5-tris(1-phenyl-1H-benzo[d]imidazole-2-yl)benzene (TPBi). 
     However, embodiments of the present disclosure are not limited thereto, for example, tris(8-hydroxyquinolino)aluminum (Alq 3 ), 9,10-di(naphthalene-2-yl)anthracene (ADN), 2-tert-butyl-9,10-di(naphth-2-yl)anthracene (TBADN), distyrylarylene (DSA), 4,4′-bis(9-carbazolyl)-2,2′-dimethyl-biphenyl (CDBP), 2-methyl-9,10-bis(naphthalen-2-yl)anthracene (MADN), hexaphenyl cyclotriphosphazene (CP1), 1,4-bis(triphenylsilyl)benzene (UGH2), hexaphenylcyclotrisiloxane (DPSiO 3 ), octaphenylcyclotetra siloxane (DPSiO 4 ), etc. may be used as a host material. 
     The emission layer EML may include a compound represented by Formula M-a or Formula M-b below. The compound represented by Formula M-a or Formula M-b below may be used as a phosphorescence dopant material. 
     
       
         
         
             
             
         
       
     
     In Formula M-a above, Y 1  to Y 4  and Z 1  to Z 4  may be each independently CR 1  or N, R 1  to R 4  may be each independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted amine group, a substituted or unsubstituted thio group, a substituted or unsubstituted oxy group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, or may be bonded to an adjacent group to form a ring. In Formula M-a, m is 0 or 1, and n is 2 or 3. In Formula M-a, when m is 0, n is 3, and when m is 1, n is 2. 
     The compound represented by Formula M-a may be used as a phosphorescent dopant. The compound represented by Formula M-a may be represented by any one selected from among Compound M-a1 to Compound M-a25 below. However, Compounds M-a1 to M-a25 below are examples, and the compound represented by Formula M-a is not limited to those represented by Compounds M-a1 to M-a25 below. 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     Formula M-a1 and Formula M-a2 may be used as a red dopant material. Formula M-a3 to Formula M-a7 may be used as a green dopant material. 
     
       
         
         
             
             
         
       
     
     In Formula M-b, Q 1  to Q 4  may be each independently C or N, and C1 to C4 are each independently a substituted or unsubstituted hydrocarbon ring having 5 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heterocycle having 2 to 30 ring-forming carbon atoms. e1 to e4 may be each independently 0 or 1. L 21  to L 24  may be each independently a direct linkage, 
     
       
         
         
             
             
         
       
     
     a substituted or unsubstituted divalent alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms. 
     In Formula M-b, d1 to d4 may be each independently an integer of 0 to 4. R 31  to R 39  may be each independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted divalent alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, or may be other bonded to an adjacent group to form a ring. 
     The compound represented by Formula M-b may be used as a blue phosphorescence dopant or a green phosphorescence dopant. The compound represented by Formula M-b may be represented by any one selected from among the compounds below. However, the compounds below are examples, and the compound represented by Formula M-b is not limited to those represented by the compounds below. 
     
       
         
         
             
             
         
       
     
     In the above compounds, R, R 38 , and R 39  may be each independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. 
     The emission layer EML may include a compound represented by any one selected from among Formula F-a to Formula F-c below. The compound represented by Formula F-a or Formula F-c below may be used as a fluorescence dopant material. 
     
       
         
         
             
             
         
       
     
     In Formula F-a above, two selected from among R a  to R j  may each independently be substituted with 
     
       
         
         
             
             
         
       
     
     The others, which are not substituted with 
     
       
         
         
             
             
         
       
     
     among R a  to R j  may be each independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. In 
     
       
         
         
             
             
         
       
     
     Ar 1  and Ar 2  may be each independently a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. For example, at least one of Ar 1  or Ar 2  may be a heteroaryl group containing O or S as a ring-forming atom. 
     
       
         
         
             
             
         
       
     
     In Formula F-b above, R a  and R b  may be each independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, or may be bonded to an adjacent group to form a ring. Ar 1  to Ar 4  may be each independently a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. 
     In Formula F-b, U and V may be each independently a substituted or unsubstituted hydrocarbon ring having 5 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heterocycle having 2 to 30 ring-forming carbon atoms. 
     In Formula F-b, the number of rings represented by U and V may be each independently 0 or 1. For example, in Formula F-b, when the number of U or V is 1, one ring constitutes a fused ring at a portion indicated by U or V, and when the number of U or V is 0, a ring indicated by U or V does not exist. In some embodiments, when the number of U is 0 and the number of V is 1, or when the number of U is 1 and the number of V is 0, the fused ring having a fluorene core in Formula F-b may be a cyclic compound having four rings. In addition, when each number of U and V is 0, the fused ring in Formula F-b may be a cyclic compound having three rings. In addition, when each number of U and V is 1, the fused ring having a fluorene core in Formula F-b may be a cyclic compound having five rings. 
     
       
         
         
             
             
         
       
     
     In Formula F-c, A 1  and A 2  may be each independently O, S, Se, or NR m , and R m  may be a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. R 1  to R 11  may be each independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amine group, a substituted or unsubstituted boryl group, a substituted or unsubstituted oxy group, a substituted or unsubstituted thio group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, or may be bonded to an adjacent group to form a ring. 
     In Formula F-c, A 1  and A 2  may each independently be bonded to substituents of an adjacent ring to form a condensed ring. For example, when A 1  and A 2  are each independently NR m , A 1  may be bonded to R 4  or R 5  to form a ring. In addition, A 2  may be bonded to R 7  or R 8  to form a ring. 
     In an embodiment, the emission layer EML may include any suitable dopant material. In some embodiments, the emission layer EML may include styryl derivatives (e.g., 1,4-bis[2-(3-N-ethylcarbazolyl)vinyl]benzene (BCzVB), 4-(di-p-tolylamino)-4′-[(di-p-tolylamino)styryl]stilbene (DPAVB), and/or N-(4-((E)-2-(6-((E)-4-(diphenylamino)styryl)naphthalen-2-yl)vinyl)phenyl)-N-phenylbenzenamine (N-BDAVBi), 4,4′-bis[2-(4-(N,N-diphenylamino)phenyl)vinyl]biphenyl(DPAVBi), perylene and/or derivatives thereof (e.g., 2,5,8,11-tetra-t-butylperylene (TBP)), pyrene and/or derivatives thereof (e.g., 1,1-dipyrene, 1,4-dipyrenylbenzene, 1,4-bis(N,N-diphenylamino)pyrene), etc. 
     The emission layer EML may include any suitable phosphorescent dopant material. For example, a metal complex containing iridium (Ir), platinum (Pt), osmium (Os), aurum (Au), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu), terbium (Tb), or thulium (Tm) may be used as a phosphorescent dopant. In some embodiments, iridium(III) bis(4,6-difluorophenylpyridinato-N,C2′)picolinate (Flrpic), bis(2,4-difluorophenylpyridinato)-tetrakis(1-pyrazolyl)borate iridium(III) (Fir6), and/or platinum octaethyl porphyrin (PtOEP) may be used as a phosphorescence dopant. However, embodiments of the present disclosure are not limited thereto. 
     The emission layer EML may include a quantum dot material. The core of the quantum dot may be selected from among a Group II-VI compound, a Group III-VI compound, a Group I-III-IV compound, a Group III-V compound, a Group III-II-V compound, a Group IV-VI compound, a Group IV element, a Group IV compound, and a combination thereof. 
     The Group II-VI compound may be selected from the group consisting of a binary compound selected from the group consisting of CdSe, CdTe, CdS, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, and a mixture thereof, a ternary compound selected from the group consisting of CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, and a mixture thereof, and a quaternary compound selected from the group consisting of HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, and a mixture thereof. 
     The Group III-VI compound may include a binary compound such as In 2 S 3  and/or In 2 Se 3 , a ternary compound such as InGaS 3  and/or InGaSe 3 , or any combination thereof. 
     The Group I-III-VI compound may be selected from a ternary compound selected from the group consisting of AgInS, AgInS 2 , CuInS, CuInS 2 , AgGaS 2 , CuGaS 2  CuGaO 2 , AgGaO 2 , AgAlO 2 , a mixture thereof, and a quaternary compound such as AgInGaS 2  and/or CuInGaS 2 . 
     The Group III-V compound may be selected from the group consisting of a binary compound selected from the group consisting of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, and a mixture thereof, a ternary compound selected from the group consisting of GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InAlP, InNP, InNAs, InNSb, InPAs, InPSb, and a mixture thereof, and a quaternary compound selected from the group consisting of GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, and a mixture thereof. The Group III-V compound may further include a Group II metal. For example, InZnP, etc. may be selected as a Group III-II-V compound. 
     The Group IV-VI compound may be selected from the group consisting of a binary compound selected from the group consisting of SnS, SnSe, SnTe, PbS, PbSe, PbTe, and a mixture thereof, a ternary compound selected from the group consisting of SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, and a mixture thereof, and a quaternary compound selected from the group consisting of SnPbSSe, SnPbSeTe, SnPbSTe, and a mixture thereof. The Group IV element may be selected from the group consisting of Si, Ge, and a mixture thereof. The Group IV compound may be a binary compound selected from the group consisting of SiC, SiGe, and a mixture thereof. 
     In this case, a binary compound, a ternary compound, and/or a quaternary compound may be present in a particle having a uniform (e.g., substantially uniform) concentration distribution, or may be present in the same particle with a partially different concentration. In addition, a core/shell structure in which one quantum dot surrounds another quantum dot may also be possible. The core/shell structure may have a concentration gradient in which the concentration of elements present in the shell decreases along a direction toward the core. 
     In some embodiments, the quantum dot may have the above-described core/shell structure including a core containing nanocrystals and a shell surrounding the core. The shell of the quantum dot may serve as a protection layer to prevent or reduce the chemical deformation of the core so as to maintain semiconductor properties, and/or a charging layer to impart electrophoresis properties to the quantum dot. The shell may be a single layer or a multilayer. An example of the shell of the quantum dot may include a metal and/or non-metal oxide, a semiconductor compound, or a combination thereof. 
     For example, the metal and/or non-metal oxide may be a binary compound such as SiO 2 , Al 2 O 3 , TiO 2 , ZnO, MnO, Mn 2 O 3 , Mn 3 O 4 , CuO, FeO, Fe 2 O 3 , Fe 3 O 4 , CoO, Co 3 O 4 , and/or NiO, and/or a ternary compound such as MgAl 2 O 4 , CoFe 2 O 4 , NiFe 2 O 4 , and/or CoMn 2 O 4 , but embodiments of the present disclosure are not limited thereto. 
     Also, the semiconductor compound may be, for example, CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnSeS, ZnTeS, GaAs, GaP, GaSb, HgS, HgSe, HgTe, InAs, InP, InGaP, InSb, AlAs, AlP, AlSb, etc., but embodiments of the present disclosure are not limited thereto. 
     The quantum dot may have a full width of half maximum (FWHM) of a light emission wavelength spectrum of about 45 nm or less, about 40 nm or less, or, for example, about 30 nm or less, and color purity and/or color reproducibility may be improved in the above range. In addition, light emitted through such a quantum dot is emitted in all directions (e.g., substantially all directions), and thus a wide viewing angle may be improved. 
     In addition, the form of the quantum dot is not particularly limited and may be any suitable form generally used in the art. In some embodiments, the quantum dot in the form of spherical, pyramidal, multi-arm, and/or cubic nanoparticles, nanotubes, nanowires, nanofibers, nanoplate particles, etc. may be used. The quantum dot may control the color of emitted light according to the particle size thereof, and accordingly, the quantum dot may have various suitable emission colors such as blue, red, or green. 
     In the light emitting element ED of an embodiment as illustrated, an electron transport region ETR is provided on the emission layer EML. The electron transport region ETR may include at least one of the hole blocking layer HBL, the electron transport layer ETL, or the electron injection layer EIL, but embodiments of the present disclosure are not limited thereto. 
     The electron transport region ETR may have a single layer formed of a single material, a single layer formed of a plurality of different materials, or a multilayer structure including a plurality of layers formed of a plurality of different materials. For example, the electron transport region ETR may have a single layer structure of the electron injection layer EIL or the electron transport layer ETL, and may have a single layer structure formed of an electron injection material and an electron transport material. In addition, the electron transport region ETR may have a single layer structure formed of a plurality of different materials, or may have a structure in which an electron transport layer ETL/electron injection layer EIL, a hole blocking layer HBL/electron transport layer ETL/electron injection layer EIL are stacked in order from the emission layer EML, but embodiments of the present disclosure are not limited thereto. The electron transport region ETR may have a thickness, for example, from about 1,000 Å to about 1,500 Å. 
     The electron transport region ETR may be formed by using various suitable methods such as a vacuum deposition method, a spin coating method, a cast method, a Langmuir-Blodgett (LB) method, an inkjet printing method, a laser printing method, a laser induced thermal imaging (LITI) method, etc. 
     The electron transport region ETR may include a compound represented by Formula ET-1 below: 
     
       
         
         
             
             
         
       
     
     In Formula ET-1, at least one selected from among X 1  to X 3  may be N, and the rest may be CR a . R a  may be a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. Ar 1  to Ar 3  may be each independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. 
     In Formula ET-1, a to c may be each independently an integer of 0 to 10. In Formula ET-1, L 1  to L 3  may be each independently a direct linkage, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms. When a to c are an integer of 2 or more, L 1  to L 3  may be each independently a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 30 ring-forming carbon atoms. 
     The electron transport region ETR may include an anthracene-based compound. However, embodiments of the present disclosure are not limited thereto, and the electron transport region ETR may include, for example, tris(8-hydroxyquinolinato)aluminum (Alq 3 ), 1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene, 2,4,6-tris(3′-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine, 2-(4-(N-phenylbenzoimidazol-1-yl)phenyl)-9,10-dinaphthylanthracene, 1,3,5-tri(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene (TPBi), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline (Bphen), 3-(4-biphenylyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ), 4-(naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole (NTAZ), 2-(4-biphenylyI)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (tBu-PBD), bis(2-methyl-8-quinolinolato-N1,O8)-(1,1′-biphenyl-4-olato)aluminum (BAlq), berylliumbis(benzoquinolin-10-olate) (Bebq 2 ), 9,10-di(naphthalene-2-yl)anthracene (ADN), 1,3-Bis[3,5-di(pyridin-3-yl)phenyl]benzene (BmPyPhB), or a mixture thereof. 
     In addition, the electron transport regions ETR may include a metal halide such as LiF, NaCl, CsF, RbCl, RbI, CuI, and/or KI, a lanthanide metal such as Yb, and/or a co-deposited material of the metal halide and the lanthanide metal. For example, the electron transport region ETR may include KI:Yb, RbI:Yb, LiF:Yb, etc. as a co-deposited material. The electron transport region ETR may be formed using a metal oxide such as Li 2 O and/or BaO, and/or 8-hydroxyl-lithium quinolate (Liq), etc., but embodiments of the present disclosure are not limited thereto. The electron transport region ETR may also be formed of a mixture of an electron transport material and an insulating organometallic salt. The organometallic salt may be a material having an energy band gap of about 4 eV or more. In some embodiments, the organometallic salt may include, for example, a metal acetate, a metal benzoate, a metal acetoacetate, a metal acetylacetonate, and/or a metal stearate. 
     The electron transport region ETR may further include at least one of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), diphenyl(4-(triphenylsilyl)phenyl)phosphine oxide (TSPO1), or 4,7-diphenyl-1,10-phenanthroline (Bphen) in addition to the above-described materials, but embodiments of the present disclosure are not limited thereto. The electron transport region ETR may include the above-described compounds of the electron transport region in at least one of the electron injection layer EIL, the electron transport layer ETL, or the hole blocking layer HBL. 
     When the electron transport region ETR includes the electron transport layer ETL, the electron transport layer ETL may have a thickness of about 100 Å to about 1,000 Å, for example, about 150 Å to about 500 Å. If the thickness of the electron transport layer ETL satisfies the aforementioned range, suitable or satisfactory electron transport characteristics may be obtained without a substantial increase in driving voltage. When the electron transport region ETR includes the electron injection layer EIL, the electron injection layer EIL may have a thickness of about 1 Å to about 100 Å, for example, about 3 Å to about 90 Å. If the thickness of the electron injection layer EIL satisfies the above-described range, suitable or satisfactory electron injection characteristics may be obtained without a substantial increase in driving voltage. 
     The second electrode EL 2  is provided on the electron transport region ETR. The second electrode EL 2  may be a common electrode. The second electrode EL 2  may be a cathode or an anode, but embodiments of the present disclosure are not limited thereto. For example, when the first electrode EL 1  is an anode, the second electrode EL 2  may be a cathode, and when the first electrode EL 1  is a cathode, the second electrode EL 2  may be an anode. The second electrode EL 2  may include at least one selected from among Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF, Mo, Ti, W, In, Sn, Zn, a compound of two or more thereof, a mixture of two or more thereof, and an oxide thereof. 
     The second electrode EL 2  may be a transmissive electrode, a transflective electrode, or a reflective electrode. When the second electrode EL 2  is a transmissive electrode, the second electrode EL 2  may be formed of a transparent metal oxide, for example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium tin zinc oxide (ITZO), etc. 
     When the second electrode EL 2  is a transflective electrode or a reflective electrode, the second electrode EL 2  may include Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF/Ca, LiF/Al, Mo, Ti, Yb, W, a compound thereof, or mixture thereof (e.g., AgMg, AgYb, and/or MgAg). In some embodiments, the second electrode EL 2  may have a multilayer structure including a reflective film or a transflective film formed of the above-described materials, and a transparent conductive film formed of ITO, IZO, ZnO, ITZO, etc. For example, the second electrode EL 2  may include the above-described metal materials, combinations of at least two metal materials of the above-described metal materials, oxides of the above-described metal materials, and/or the like. 
     In some embodiments, the second electrode EL 2  may be connected with an auxiliary electrode. If the second electrode EL 2  is connected with the auxiliary electrode, the resistance of the second electrode EL 2  may decrease. 
     A capping layer CPL may further be on the second electrode EL 2  of the light emitting element ED of an embodiment. The capping layer CPL may include a multilayer or a single layer. 
     In an embodiment, the capping layer CPL may be an organic layer and/or an inorganic layer. For example, when the capping layer CPL contains an inorganic material, the inorganic material may include an alkaline metal compound (for example, LiF), an alkaline earth metal compound (for example, MgF 2 ), SiON, SiN x , SiOy, etc. 
     For example, when the capping layer CPL includes an organic material, the organic material may include α-NPD, NPB, TPD, m-MTDATA, Alq 3 , CuPc, N4,N4,N4′,N4′-tetra(biphenyl-4-yl)biphenyl-4,4′-diamine (TPD15), 4,4′,4″-tris(carbazol -9-yl)triphenylamine (TCTA), etc., an epoxy resin, and/or acrylate such as methacrylate. However, embodiments of the present disclosure are not limited thereto, and the capping layer CPL may include at least one selected from among Compounds P1 to P5 below: 
     
       
         
         
             
             
         
       
     
     The refractive index of the capping layer CPL may be about 1.6 or more. In some embodiments, the refractive index of the capping layer CPL may be about 1.6 or 25 more with respect to light in a wavelength range of about 550 nm to about 660 nm. 
     Each of  FIGS.  7  to  10    is a cross-sectional view of a display device according to an embodiment of the present disclosure. Hereinafter, in describing the display devices of embodiments with reference to  FIGS.  7  to  10   , features that have been described with respect to  FIGS.  1  to  6    may not be described again, but their differences will be mainly described. 
     Referring to  FIG.  7   , the display device DD according to an embodiment may include a display panel DP including a display element layer DP-ED, a light control layer CCL on the display panel DP, and a color filter layer CFL. 
     In an embodiment illustrated in  FIG.  7   , the display panel DP may include a base layer BS, a circuit layer DP-CL provided on the base layer BS, and the display element layer DP-ED, and the display element layer DP-ED may include a light emitting element ED. 
     The light emitting element ED may include a first electrode EL 1 , a hole transport region HTR on the first electrode EL 1 , an emission layer EML on the hole transport region HTR, an electron transport region ETR on the emission layer EML, and a second electrode EL 2  on the electron transport region ETR. The structures of the light emitting elements of  FIGS.  3  to  6    as described above may be equally applied to the structure of the light emitting element ED illustrated in  FIG.  7   . 
     Referring to  FIG.  7   , the light emission layer EML in the display device DD-a may be in an opening OH defined in a pixel defining film PDL. For example, the emission layer EML which is divided by the pixel defining film PDL and provided corresponding to each light emitting regions PXA-R, PXA-G, and PXA-B may emit light in the same wavelength range. In the display device DD of an embodiment, the emission layer EML may emit blue light. Unlike the configuration illustrated, in an embodiment, the emission layer EML may be provided as a common layer in the entire light emitting regions PXA-R, PXA-G, and PXA-B. 
     The light control layer CCL may be on the display panel DP. The light control layer CCL may include a light conversion body. The light conversion body may be a quantum dot, a phosphor, and/or the like. The light conversion body may emit provided light by converting the wavelength thereof. For example, the light control layer CCL may be a layer containing the quantum dot and/or a layer containing the phosphor. 
     The light control layer CCL may include a plurality of light control parts CCP 1 , CCP 2 , and CCP 3 . The light control parts CCP 1 , CCP 2 , and CCP 3  may be spaced apart from each other. 
     Referring to  FIG.  7   , divided patterns BMP may be between the light control parts CCP 1 , CCP 2 , and CCP 3 , which are spaced apart from each other, but embodiments of the present disclosure are not limited thereto.  FIG.  7    illustrates that the divided patterns BMP do not overlap the light control parts CCP 1 , CCP 2 , and CCP 3 , but at least a portion of the edges of the light control parts CCP 1 , CCP 2 , and CCP 3  may overlap the divided patterns BMP. 
     The light control layer CCL may include a first light control part CCP 1  containing a first quantum dot QD 1  which converts a first color light provided from the light emitting element ED into a second color light, a second light control part CCP 2  containing a second quantum dot QD 2  which converts the first color light into a third color light, and a third light control part CCP 3  which transmits the first color light. 
     In an embodiment, the first light control part CCP 1  may provide red light that is the second color light, and the second light control part CCP 2  may provide green light that is the third color light. The third light control part CCP 3  may provide blue light by transmitting the blue light that is the first color light provided from the light emitting element ED. For example, the first quantum dot QD 1  may be a red quantum dot, and the second quantum dot QD 2  may be a green quantum dot. The same as described above may be applied with respect to the quantum dots QD 1  and QD 2 . 
     In addition, the light control layer CCL may further include a scatterer SP (e.g., a light scatterer SP). The first light control part CCP 1  may include the first quantum dot QD 1  and the scatterer SP, the second light control part CCP 2  may include the second quantum dot QD 2  and the scatterer SP, and the third light control part CCP 3  may not include any quantum dot but may include the scatterer SP. 
     The scatterer SP may be inorganic particles. For example, the scatterer SP may include at least one of TiO 2 , ZnO, Al 2 O 3 , SiO 2 , or hollow sphere silica. The scatterer SP may include any one selected from among TiO 2 , ZnO, Al 2 O 3 , SiO 2 , and hollow sphere silica, or may be a mixture of at least two materials selected from among TiO 2 , ZnO, Al 2 O 3 , SiO 2 , and hollow sphere silica. 
     The first light control part CCP 1 , the second light control part CCP 2 , and the third light control part CCP 3  each may include base resins BR 1 , BR 2 , and BR 3  in which the quantum dots QD 1  and QD 2  and the scatterer SP are dispersed. In an embodiment, the first light control part CCP 1  may include the first quantum dot QD 1  and the scatterer SP dispersed in a first base resin BR 1 , the second light control part CCP 2  may include the second quantum dot QD 2  and the scatterer SP dispersed in a second base resin BR 2 , and the third light control part CCP 3  may include the scatterer SP dispersed in a third base resin BR 3 . The base resins BR 1 , BR 2 , and BR 3  are media in which the quantum dots QD 1  and QD 2  and the scatterer SP are dispersed, and may be formed of various suitable resin compositions, which may be generally referred to as a binder. For example, the base resins BR 1 , BR 2 , and BR 3  may be acrylic-based resins, urethane-based resins, silicone-based resins, epoxy-based resins, etc. The base resins BR 1 , BR 2 , and BR 3  may be transparent resins. In an embodiment, the first base resin BR 1 , the second base resin BR 2 , and the third base resin BR 3  may be the same as or different from each other. 
     The light control layer CCL may include a barrier layer BFL 1 . The barrier layer BFL 1  may serve to prevent or reduce the penetration of moisture and/or oxygen (hereinafter may be referred to as “moisture/oxygen”). The barrier layer BFL 1  may block or reduce exposure of the light control parts CCP 1 , CCP 2  and CCP 3  to moisture/oxygen. The barrier layer BFL 1  may cover the light control parts CCP 1 , CCP 2 , and CCP 3 . In addition, the barrier layer BFL 2  may be provided between the light control parts CCP 1 , CCP 2 , and CCP 3  and the color filter layer CFL. 
     The barrier layers BFL 1  and BFL 2  may include at least one inorganic layer. In some embodiments, the barrier layers BFL 1  and BFL 2  may include an inorganic material. For example, the barrier layers BFL 1  and BFL 2  may include a silicon nitride, an aluminum nitride, a zirconium nitride, a titanium nitride, a hafnium nitride, a tantalum nitride, a silicon oxide, an aluminum oxide, a titanium oxide, a tin oxide, a cerium oxide, a silicon oxynitride, a metal thin film which secures a transmittance, etc. The barrier layers BFL 1  and BFL 2  may further include an organic film. The barrier layers BFL 1  and BFL 2  may be formed of a single layer or a plurality of layers. 
     In the display device DD of an embodiment, the color filter layer CFL may be on the light control layer CCL. For example, the color filter layer CFL may be directly on the light control layer CCL. In this case, the barrier layer BFL 2  may be omitted. 
     The color filter layer CFL may include filters CF 1 , CF 2 , and CF 3 . The color filter layer CFL may include a first filter CF 1  configured to transmit the second color light, a second filter CF 2  configured to transmit the third color light, and a third filter CF 3  configured to transmit the first color light. For example, the first filter CF 1  may be a red filter, the second filter CF 2  may be a green filter, and the third filter CF 3  may be a blue filter. The filters CF 1 , CF 2 , and CF 3  each may include a polymeric photosensitive resin and a pigment and/or dye. The first filter CF 1  may include a red pigment and/or dye, the second filter CF 2  may include a green pigment and/or dye, and the third filter CF 3  may include a blue pigment and/or dye. 
     Embodiments of the present disclosure are not limited thereto, and the third filter CF 3  may not include a pigment or dye. The third filter CF 3  may include a polymeric photosensitive resin and may not include a pigment or dye. The third filter CF 3  may be transparent. The third filter CF 3  may be formed of a transparent photosensitive resin. 
     Furthermore, in an embodiment, the first filter CF 1  and the second filter CF 2  may be a yellow filter. The first filter CF 1  and the second filter CF 2  may not be separated but be provided as one filter. The first to third filters CF 1 , CF 2 , and CF 3  may correspond to the red light emitting region PXA-R, the green light emitting region PXA-G, and the blue light emitting region PXA-B, respectively. 
     A base substrate BL may be on the color filter layer CFL. The base substrate BL may be a member which provides a base surface that the color filter layer CFL, the light control layer CCL, and the like are on. The base substrate BL may be a glass substrate, a metal substrate, a plastic substrate, etc. However, embodiments of the present disclosure are not limited thereto, and the base substrate BL may be an inorganic layer, an organic layer, or a composite material layer. In addition, unlike the configuration illustrated, in an embodiment, the base substrate BL may be omitted. 
       FIG.  8    is a cross-sectional view illustrating a portion of a display device according to an embodiment of the present disclosure.  FIG.  8    illustrates a cross-sectional view of a part corresponding to the display panel DP of  FIG.  7   . In the display device DD-TD of an embodiment, the light emitting element ED-BT may include a plurality of light emitting structures OL-B 1 , OL-B 2 , and OL-B 3 . The light emitting element ED-BT may include a first electrode EL 1  and a second electrode EL 2  which face each other, and the plurality of light emitting structures OL-B 1 , OL-B 2 , and OL-B 3  sequentially stacked in the thickness direction between the first electrode EL 1  and the second electrode EL 2 . The light emitting structures OL-B 1 , OL-B 2 , and OL-B 3  each may include an emission layer EML ( FIG.  7   ) and a hole transport region HTR and an electron transport region ETR with the emission layer EML ( FIG.  7   ) therebetween. In some embodiments, the light emitting element ED-BT included in the display device DD-TD of an embodiment may be a light emitting element having a tandem structure and including a plurality of emission layers. 
     In an embodiment illustrated in  FIG.  8   , all light beams respectively emitted from the light emitting structures OL-B 1 , OL-B 2 , and OL-B 3  may be blue light. However, embodiments of the present disclosure are not limited thereto, and the light beams respectively emitted from the light emitting structures OL-B 1 , OL-B 2 , and OL- 3  may have wavelength ranges different from each other. For example, the light emitting element ED-BT including the plurality of light emitting structures OL-B 1 , OL-B 2  and OL-B 3  which emit light beams having wavelength ranges different from each other may emit white light. 
     A charge generation layers CGL 1  and CGL 2  may be between two of the neighboring light emitting structures OL-B 1 , OL-B 2 , and OL-B 3 . The charge generation layers CGL 1  and CGL 2  may include a p-type charge generation layer and/or an n-type charge generation layer. 
     Referring to  FIG.  9   , the display device DD-b according to an embodiment may include light emitting elements ED- 1 , ED- 2 , and ED- 3  in which two emission layers are stacked. Compared to the display device DD of an embodiment illustrated in  FIG.  2   , an embodiment illustrated in  FIG.  9    has a difference in that the first to third light emitting elements ED- 1 , ED- 2 , and ED- 3  each include two emission layers stacked in the thickness direction. In each of the first to third light emitting elements ED- 1 , ED- 2 , and ED- 3 , the two emission layers may emit light in the same wavelength region. 
     The first light emitting element ED- 1  may include a first red emission layer EML-R 1  and a second red emission layer EML-R 2 . The second light emitting element ED- 2  may include a first green emission layer EML-G 1  and a second green emission layer EML-G 2 . The third light emitting element ED- 3  may include a first blue emission layer EML-B 1  and a second blue emission layer EML-B 2 . An emission auxiliary part OG may be between the first red emission layer EML-R 1  and the second red emission layer EML-R 2 , between the first green emission layer EML-G 1  and the second green emission layer EML-G 2 , and between the first blue emission layer EML-B 1  and the second blue emission layer EML-B 2 . 
     The emission auxiliary part OG may include a single layer or a multilayer. The emission auxiliary part OG may include a charge generation layer. For example, the emission auxiliary part OG may include an electron transport region, a charge generation layer, and a hole transport region that are sequentially stacked. The emission auxiliary part OG may be provided as a common layer in the whole of the first to third light emitting elements ED- 1 , ED- 2 , and ED- 3 . However, embodiments of the present disclosure are not limited thereto, and the emission auxiliary part OG may be provided by being patterned within the openings OH defined in the pixel defining film PDL. 
     The first red emission layer EML-R 1 , the first green emission layer EML-G 1 , and the first blue emission layer EML-B 1  may be between the hole transport region HTR and the emission auxiliary part OG. The second red emission layer EML-R 2 , the second green emission layer EML-G 2 , and the second blue emission layer EML-B 2  may be between the emission auxiliary part OG and the electron transport region ETR. 
     In some embodiments, the first light emitting element ED- 1  may include the first electrode EL 1 , the hole transport region HTR, the second red emission layer EML-R 2 , the emission auxiliary part OG, the first red emission layer EML-R 1 , the electron transport region ETR, and the second electrode EL 2  that are sequentially stacked. The second light emitting element ED- 2  may include the first electrode EL 1 , the hole transport region HTR, the second green emission layer EML-G 2 , the emission auxiliary part OG, the first green emission layer EML-G 1 , the electron transport region ETR, and the second electrode EL 2  that are sequentially stacked. The third light emitting element ED- 3  may include the first electrode EL 1 , the hole transport region HTR, the second blue emission layer EML-B 2 , the emission auxiliary part OG, the first blue emission layer EML-B 1 , the electron transport region ETR, and the second electrode EL 2  that are sequentially stacked. 
     An optical auxiliary layer PL may be on the display element layer DP-ED. The optical auxiliary layer PL may include a polarizing layer. The optical auxiliary layer PL may be on the display panel DP and control reflected light in the display panel DP due to external light. Unlike the configuration illustrated, the optical auxiliary layer PL in the display device according to an embodiment may be omitted. 
     Unlike  FIGS.  8  and  9   ,  FIG.  10    illustrates that a display device DD-c includes four light emitting structures OL-B 1 , OL-B 2 , OL-B 3 , and OL-C 1 . A light emitting element ED-CT may include a first electrode EL 1  and a second electrode EL 2  which face each other, and first to fourth light emitting structures OL-B 1 , OL-B 2 , OL-B 3 , and OL-C 1  that are sequentially stacked in the thickness direction between the first electrode EL 1  and the second electrode EL 2 . 
     Charge generation layers CGL 1 , CGL 2 , and CGL 3  may be between the first to fourth light emitting structures OL-B 1 , OL-B 2 , OL-B 3 , and OL-C 1 . The charge generation layers CGL 1 , CGL 2  and CGL 3  may include a p-type charge generation layer and/or an n-type charge generation layer. Among the four light emitting structures, the first to third light emitting structures OL-B 1 , OL-B 2 , and OL-B 3  may emit blue light, and the fourth light emitting structure OL-C 1  may emit green light. However, embodiments of the present disclosure are not limited thereto, and the first to fourth light emitting structures OL-B 1 , OL-B 2 , OL-B 3 , and OL-C 1  may emit light beams in different wavelength regions. 
     Hereinafter, with reference to Examples and Comparative Examples, an amine compound according to embodiments of the present disclosure and a light emitting element of embodiments of the present disclosure will be described in more detail. In addition, the Examples described below are only illustrations to assist the understanding of the present disclosure, and the scope of the present disclosure is not limited thereto. 
     EXAMPLES 
     1. Synthesis of Amine Compound of Examples 
     First, a synthetic method of an amine compound according to the present embodiment will be described in more detail by illustrating the synthetic methods of Compounds 15, 18, 29, 30, 43, 48, 53, 60, 71, 74, 85, 89, 213, 217, 227, and 231. In addition, in the following descriptions, the synthetic method of the amine compound is provided as an example, but the synthetic method of the compound according to an embodiments of the present disclosure is not limited to the Examples below. 
     In the synthetic method of the amine compound described below, room temperature is from about 20° C. to about 29° C. In the synthetic method of the amine compound described below, a yield is a ratio of the mole number of products to the mole number of reactants when the weight of the reactants is converted to the mole number and the weight of the products is converted to the mole number. In the synthetic method of the amine compound described below, “RT” means room temperature. 
     (1) Synthesis of Compound 15 
     Amine Compound 15 according to an example may be synthesized by, for example, the steps shown in Reaction Scheme 1 below: 
     
       
         
         
             
             
         
       
     
     Synthesis of Intermediate 15-2 
     Intermediate 15-1 (1.97 g), 2-bromo-4′-chloro-3-iodo-1,1′-biphenyl (3.93 g), Pd 2 (dba) 3  (0.46 g), P(t-Bu) 3  (0.21 g) and NaO t Bu (2.44 g) were dissolved in toluene (50 mL) and then the resulting mixture was stirred at about 100° C. for about 1 hour. This reaction solution was cooled to room temperature and then quenched with water, and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Intermediate 15-2 (3.47 g, yield: 75%). 
     Synthesis of Intermediate 15-3 
     A solution, in which Intermediate 15-2 (4.62 g) was dissolved in tetrahydrofuran (THF, 50 mL), was stirred at about −78° C. n-BuLi (2.5 M in hexane, 8 mL) was slowly added dropwise to this solution at about −78° C. This solution was stirred at room temperature for about 12 hours. This reaction solution was quenched with water and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Intermediate 15-3 (2.15 g, yield: 56%). 
     Synthesis of Intermediate 15-4 
     Intermediate 15-3 (3.83 g) was dissolved in HCl (6 mL) and acetic acid (AcOH, 30 mL), and then the resulting mixture was stirred at about 60° C. for about 6 hours. This reaction solution was cooled to room temperature and then quenched with water, and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Intermediate 15-4 (2.92 g, yield: 80%). 
     Synthesis of Compound 15 
     Intermediate 15-4 (3.65 g), 9,9-dimethyl-N-phenyl-9H-fluoren-2-amine (2.85 g), Pd 2 (dba) 3  (0.46 g), P(t-Bu) 3  (0.21 g), and NaO t Bu (2.44 g) were dissolved in o-xylene (50 mL), and then the resulting mixture was stirred at about 150° C. for about 1 hour. This reaction solution was cooled to room temperature and then quenched with water, and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Compound 15 (5.31 g, yield: 77%). 
     (2) Synthesis of Compound 18 
     Amine Compound 18 according to an example may be synthesized by, for example, the steps shown in Reaction Scheme 2 below: 
     
       
         
         
             
             
         
       
     
     Synthesis of Compound 18 
     Intermediate 15-4 (3.65 g), N-([1,1′-biphenyl]-2-yl)-9,9-dimethyl-9H-fluoren-2-amine (3.61 g), Pd 2 (dba) 3  (0.46 g), P(t-Bu) 3  (0.21 g), and NaO t Bu (2.44 g) were dissolved in o-xylene (50 mL), and then the resulting mixture was stirred at about 150° C. for about 1 hour. This reaction solution was cooled to room temperature and then quenched with water, and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Compound 18 (6.35 g, yield: 83%). 
     (3) Synthesis of Compound 29 
     Amine Compound 29 according to an example may be synthesized by, for example, the steps shown in Reaction Scheme 3 below: 
     
       
         
         
             
             
         
       
     
     Synthesis of Compound 29 
     Intermediate 15-4 (3.65 g), N,9,9-triphenyl-9H-fluoren-2-amine (4.09 g), Pd 2 (dba) 3  (0.46 g), P(t-Bu) 3  (0.21 g), and NaO t Bu (2.44 g) were dissolved in o-xylene (50 mL), and then the resulting mixture was stirred at about 150° C. for about 1 hour. This reaction solution was cooled to room temperature and then quenched with water, and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Compound 29 (5.57 g, yield: 78%). 
     (4) Synthesis of Compound 30 
     Amine Compound 30 according to an example may be synthesized by, for example, the steps shown in Reaction Scheme 4 below: 
     
       
         
         
             
             
         
       
     
     Synthesis of Compound 30 
     Intermediate 15-4 (3.65 g), N-([1,1′-biphenyl]-4-yl)-9,9-diphenyl-9H-fluoren-2-amine (4.85 g), Pd 2 (dba) 3  (0.46 g), P(t-Bu) 3  (0.21 g), and NaO t Bu (2.44 g) were dissolved in o-xylene (50 mL), and then the resulting mixture was stirred at about 150° C. for about 1 hour. This reaction solution was cooled to room temperature and then quenched with water, and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Compound 30 (6.77 g, yield: 76%). 
     (5) Synthesis of Compound 43 
     Amine Compound 43 according to an example may be synthesized by, for example, the steps shown in Reaction Scheme 5 below: 
     
       
         
         
             
             
         
       
     
     Synthesis of Compound 43 
     Intermediate 15-4 (3.65 g), N-phenyl-9,9′-spirobi[fluoren]-2-amine (4.07 g), Pd 2 (dba) 3  (0.46 g), P(t-Bu) 3  (0.21 g), and NaO t Bu (2.44 g) were dissolved in o-xylene (50 mL), and then the resulting mixture was stirred at about 150° C. for about 1 hour. This reaction solution was cooled to room temperature and then quenched with water, and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Compound 43 (6.99 g, yield: 86%). 
     (6) Synthesis of Compound 48 
     Amine Compound 48 according to an example may be synthesized by, for example, the steps shown in Reaction Scheme 6 below: 
     
       
         
         
             
             
         
       
     
     Synthesis of Compound 48 
     Intermediate 15-4 (3.65 g), N-(naphthalen-1-yl)-9,9′-spirobi[fluoren]-2-amine (4.57 g), Pd 2 (dba) 3  (0.46 g), P(t-Bu) 3  (0.21 g), and NaO t Bu (2.44 g) were dissolved in o-xylene (50 mL), and then the resulting mixture was stirred at about 150° C. for about 1 hour. This reaction solution was cooled to room temperature and then quenched with water, and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Compound 48 (7.76 g, yield: 90%). 
     (7) Synthesis of Compound 53 
     Amine Compound 53 according to an example may be synthesized by, for example, the steps shown in Reaction Scheme 7 below: 
     
       
         
         
             
             
         
       
     
     Synthesis of Compound 53 
     Intermediate 15-4 (3.65 g), N-(9,9′-spirobi[fluoren]-2-yl)dibenzo[b,d]thiophen-1-amine (5.13 g), Pd 2 (dba) 3  (0.46 g), P(t-Bu) 3  (0.21 g), and NaO t Bu (2.44 g) were dissolved in o-xylene (50 mL), and then the resulting mixture was stirred at about 150° C. for about 1 hour. This reaction solution was cooled to room temperature and then quenched with water, and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Compound 53 (7.44 g, yield: 81%). 
     (8) Synthesis of Compound 60 
     Amine Compound 60 according to an example may be synthesized by, for example, the steps shown in Reaction Scheme 8 below: 
     
       
         
         
             
             
         
       
     
     Synthesis of Intermediate 60-1 
     Intermediate 15-1 (1.97 g), 2-bromo-4″-chloro-3-iodo-1,1′:3′,1″-terphenyl (4.69 g), Pd 2 (dba) 3  (0.46 g), P(t-Bu) 3  (0.21 g), and NaO t Bu (2.44 g) were dissolved in toluene (50 mL) and then the resulting mixture was stirred at about 100° C. for about 1 hour. This reaction solution was cooled to room temperature and then quenched with water, and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Intermediate 60-1 (3.87 g, yield: 72%). 
     Synthesis of Intermediate 60-2 
     A solution, in which Intermediate 60-1 (5.38 g) was dissolved in THF (50 mL), was stirred at about −78° C. n-BuLi (2.5 M in hexane, 8 mL) was slowly added dropwise to this solution at about −78° C. This solution was stirred at room temperature for about 12 hours. This reaction solution was quenched with water and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Intermediate 60-2 (2.75 g, yield: 60%). 
     Synthesis of Intermediate 60-3 
     Intermediate 60-2 (4.59 g) was dissolved in HCl (6 mL) and AcOH (30 mL), and then the resulting mixture was stirred at about 60° C. for about 6 hours. This reaction solution was cooled to room temperature and then quenched with water, and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Intermediate 60-3 (3.17 g, yield: 72%). 
     Synthesis of Compound 60 
     Intermediate 60-3 (4.41 g), N-phenyl-[1,1′-biphenyl]-2-amine (2.45 g), Pd 2 (dba) 3  (0.46 g), P(t-Bu) 3  (0.21 g), and NaO t Bu (2.44 g) were dissolved in o-xylene (50 mL), and then the resulting mixture was stirred at about 150° C. for about 1 hour. This reaction solution was cooled to room temperature and then quenched with water, and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Compound 60 (5.00 g, yield: 69%). 
     (9) Synthesis of Compound 71 
     Amine Compound 71 according to an example may be synthesized by, for example, the steps shown in Reaction Scheme 9 below: 
     
       
         
         
             
             
         
       
     
     Synthesis of Intermediate 71-1 
     Intermediate 15-1 (1.97 g), 2-bromo-4″-chloro-3-iodo-1,1′:4′,1″-terphenyl (4.69 g), Pd 2 (dba) 3  (0.46 g), P(t-Bu) 3  (0.21 g), and NaO t Bu (2.44 g) were dissolved in toluene (50 mL) and then the resulting mixture was stirred at about 100° C. for about 1 hour. This reaction solution was cooled to room temperature and then quenched with water, and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Intermediate 71-1 (4.03 g, yield: 75%). 
     Synthesis of Intermediate 71-2 
     A solution, in which Intermediate 71-1 (5.38 g) was dissolved in THF (50 mL), was stirred at about −78° C. n-BuLi (2.5 M in hexane, 8 mL) was slowly added dropwise to this solution at about −78° C. This solution was stirred at room temperature for about 12 hours. This reaction solution was quenched with water and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Intermediate 71-2 (2.75 g, yield: 60%). 
     Synthesis of Intermediate 71-3 
     Intermediate 71-2 (4.59 g) was dissolved in HCl (6 mL) and AcOH (30 mL), and then the resulting mixture was stirred at about 60° C. for about 6 hours. This reaction solution was cooled to room temperature and then quenched with water, and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Compound 71-3 (3.17 g, yield: 72%). 
     Synthesis of Compound 71 
     Intermediate 71-3 (4.41 g), 9,9-dimethyl-N-phenyl-9H-fluoren-2-amine (2.85 g), Pd 2 (dba) 3  (0.46 g), P(t-Bu) 3  (0.21 g), and NaO t Bu (2.44 g) were dissolved in o-xylene (50 mL), and then stirred at about 150° C. for about 1 hour. This reaction solution was cooled to room temperature and then quenched with water, and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Compound 71 (6.28 g, yield: 82%). 
     (10) Synthesis of Compound 74 
     Amine Compound 74 according to an example may be synthesized by, for example, the steps shown in Reaction Scheme 10 below: 
     
       
         
         
             
             
         
       
     
     Synthesis of Compound 74 
     Intermediate 71-3 (4.41 g), N-([1,1′-biphenyl]-2-yl)-9,9-dimethyl-9H-fluoren-2-amine (3.61 g), Pd 2 (dba) 3  (0.46 g), P(t-Bu) 3  (0.21 g), and NaO t Bu (2.44 g) were dissolved in o-xylene (50 mL), and then the resulting mixture was stirred at about 150° C. for about 1 hour. This reaction solution was cooled to room temperature and then quenched with water, and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Compound 74 (6.92 g, yield: 82%). 
     (11) Synthesis of Compound 85 
     Amine Compound 85 according to an example may be synthesized by, for example, the steps shown in Reaction Scheme 11 below: 
     
       
         
         
             
             
         
       
     
     Synthesis of Compound 85 
     Intermediate 71-3 (4.41 g), N,9,9-triphenyl-9H-fluoren-2-amine (4.09 g), Pd 2 (dba) 3  (0.46 g), P(t-Bu) 3  (0.21 g), and NaO t Bu (2.44 g) were dissolved in o-xylene (50 mL), and then the resulting mixture was stirred at about 150° C. for about 1 hour. This reaction solution was cooled to room temperature and then quenched with water, and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Compound 85 (6.86 g, yield: 77%). 
     (12) Synthesis of Compound 89 
     Amine Compound 89 according to an example may be synthesized by, for example, the steps shown in Reaction Scheme 12 below: 
     
       
         
         
             
             
         
       
     
     Synthesis of Compound 89 
     Intermediate 71-3 (4.41 g), N-(naphthalen-2-yl)-9,9-diphenyl-9H-fluoren-2-amine (4.59 g), Pd 2 (dba) 3  (0.46 g), P(t-Bu) 3  (0.21 g), and NaO t Bu (2.44 g) were dissolved in o-xylene (50 mL), and then the resulting mixture was stirred at about 150° C. for about 1 hour. This reaction solution was cooled to room temperature and then quenched with water, and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Compound 89 (8.09 g, yield: 86%). 
     (13) Synthesis of Compound 213 
     Amine Compound 213 according to an example may be synthesized by, for example, the steps shown in Reaction Scheme 13 below: 
     
       
         
         
             
             
         
       
     
     Synthesis of Compound 213 
     Intermediate 15-4 (3.65 g), N,9-diphenyl-9H-carbazol-3-amine (3.34 g), Pd 2 (dba) 3  (0.46 g), P(t-Bu) 3  (0.21 g), and NaO t Bu (2.44 g) were dissolved in o-xylene (50 mL), and then the resulting mixture was stirred at about 150° C. for about 1 hour. This reaction solution was cooled to room temperature and then quenched with water, and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Compound 213 (5.54 g, yield: 75%). 
     (14) Synthesis of Compound 217 
     Amine Compound 217 according to an example may be synthesized by, for example, the steps shown in Reaction Scheme 14 below: 
     
       
         
         
             
             
         
       
     
     Synthesis of Compound 217 
     Intermediate 15-4 (3.65 g), N,9-diphenyl-9H-carbazol-2-amine (3.34 g), Pd 2 (dba) 3  (0.46 g), P(t-Bu) 3  (0.21 g), and NaO t Bu (2.44 g) were dissolved in o-xylene (50 mL), and then the resulting mixture was stirred at about 150° C. for about 1 hour. This reaction solution was cooled to room temperature and then quenched with water, and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Compound 217 (5.61 g, yield: 64%). 
     (15) Synthesis of Compound 227 
     Amine Compound 227 according to an example may be synthesized by, for example, the steps shown in Reaction Scheme 15 below: 
     
       
         
         
             
             
         
       
     
     Synthesis of Compound 227 
     Intermediate 71-3 (4.41 g), N,9-diphenyl-9H-carbazol-3-amine (3.34 g), Pd 2 (dba) 3  (0.46 g), P(t-Bu) 3  (0.21 g), and NaO t Bu (2.44 g) were dissolved in o-xylene (50 mL), and then the resulting mixture was stirred at about 150° C. for about 1 hour. This reaction solution was cooled to room temperature and then quenched with water, and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Compound 227 (7.18 g, yield: 88%). 
     (16) Synthesis of Compound 231 
     Amine Compound 231 according to an example may be synthesized by, for example, the steps shown in Reaction Scheme 16 below: 
     
       
         
         
             
             
         
       
     
     Synthesis of Compound 231 
     Intermediate 71-3 (4.41 g), N,9-diphenyl-9H-carbazol-2-amine (3.34 g), Pd 2 (dba) 3  (0.46 g), P(t-Bu) 3  (0.21 g), and NaO t Bu (2.44 g) were dissolved in o-xylene (50 mL), and then the resulting mixture was stirred at about 150° C. for about 1 hour. This reaction solution was cooled to room temperature and then quenched with water, and extracted three times with ethyl ether to separate an organic layer. The separated organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to obtain residues. The obtained residues were separated and purified by column chromatography to obtain Compound 231 (7.13 g, yield: 87%). 
     2. Manufacture and Evaluation of Light Emitting Elements 
     (1) Manufacture of Light Emitting Elements 
     Light emitting elements including an amine compound of an example or a Comparative Example Compound in a hole transport layer were manufactured as follows. Compounds 15, 18, 29, 30, 43, 48, 53, 60, 71, 74, 85, 89, 213, 217, 227, and 231, which are amine compounds of the examples, were used as a hole transport layer material to manufacture the light emitting elements of Examples 1 to 16, respectively. Comparative Example Compounds C1 to C3 were used as a hole transport layer material to manufacture the light emitting elements of Comparative Examples 1 to 3, respectively. N,N′-di(naphthalene-l-yl)-N,N′-diphenyl-benzidine (NPB) was used as Comparative Example Compound C1. 
     For a first electrode, an ITO glass substrate of about 15 Ω/cm 2  (a thickness of about 1,200 Å) made by Corning Co. was cut to a size of 50 mm×50 mm×0.7 mm, cleansed by ultrasonic waves using isopropyl alcohol and pure water for about 5 minutes, and then irradiated with ultraviolet rays for about 30 minutes and exposed to ozone and cleansed. The glass substrate was installed on a vacuum deposition apparatus. 
     On the upper portion of the first electrode, 2-TNATA was deposited in vacuum to form a 600 Å-thick hole injection layer, and then a Comparative Example Compound or an Example Compound as a hole transporting compound was deposited in vacuum to form a 300 Å-thick hole transport layer. 
     On the upper portion of the hole transport layer, 9,10-di(naphthalen-2-yl)anthracene (ADN) as a blue fluorescent host and 4,4′-bis[2-(4-(N,N-diphenylamino)phenyl)vinyl]biphenyl (DPAVBi) as a blue fluorescent dopant were co-deposited at a weight ratio of 98:2 to form a 300 Å-thick emission layer. 
     On the upper portion of the emission layer, Alq 3  was deposited to form a 300 Å-thick electron transport layer, and then on the upper portion of the electron transport layer, LiF, which is a alkali metal halide, was deposited to form 10 Å-thick electron injection layer. Then, Al was deposited in vacuum to form a 3000 Å-thick second electrode of LiF/Al. 
     Materials Used to Manufacture Light Emitting Elements 
     
       
         
         
             
             
         
       
     
     The Example Compounds and Comparative Example Compounds used in Examples 1 to 16 and Comparative Examples 1 to 3 are listed in Table 1. 
     
       
         
           
               
               
             
               
                 TABLE 1 
               
               
                   
               
             
            
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 Comparative Example Compound C1 
               
               
                   
               
               
                 C1(NPB) 
                   
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 Comparative Example Compound C2 
               
               
                   
               
               
                 C2 
                   
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 Comparative Example Compound C3 
               
               
                   
               
               
                 C3 
                   
               
               
                 — 
                   
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 Compound 15 
               
               
                   
               
               
                 15 
                   
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 Compound 18 
               
               
                   
               
               
                 18 
                   
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 Compound 29 
               
               
                   
               
               
                 29 
                   
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 Compound 30 
               
               
                   
               
               
                 30 
                   
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 Compound 43 
               
               
                   
               
               
                 43 
                   
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 Compound 48 
               
               
                   
               
               
                 48 
                   
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 Compound 53 
               
               
                   
               
               
                 53 
                   
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 Compound 60 
               
               
                   
               
               
                 60 
                   
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 Compound 71 
               
               
                   
               
               
                 71 
                   
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 Compound 74 
               
               
                   
               
               
                 74 
                   
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 Compound 85 
               
               
                   
               
               
                 85 
                   
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 Compound 89 
               
               
                   
               
               
                 89 
                   
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 Compound 213 
               
               
                   
               
               
                 213 
                   
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 Compound 217 
               
               
                   
               
               
                 217 
                   
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 Compound 227 
               
               
                   
               
               
                 227 
                   
               
               
                   
               
               
                 
                   
                     
                     
                         
                         
                     
                   
                 
                 Compound 231 
               
               
                   
               
               
                 231 
               
               
                   
               
            
           
         
       
     
     (2) Evaluation of Light Emitting Element Property 
     Properties of the light emitting elements of the Examples and Comparative Examples were evaluated and the results are listed in Table 2. The properties of the light emitting elements of the Examples and Comparative Examples were measured by using a V7000 OLED IVL Test System, (Polaronix) (Mcscience Inc.). Driving voltages, brightness, and efficiencies of the light emitting elements of the Examples and Comparative Examples were measured with respect to a current density of 50 mA/cm 2 . Half service lives of the light emitting elements of Examples and Comparative Examples were measured with respect to a current density of 100 mA/cm 2 . The half service lives were determined by measuring a time taken to reduce the brightness to half of an initial brightness. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                   
                   
                   
                   
                   
                   
                 Half 
               
               
                 Examples of 
                   
                 Driving 
                   
                   
                   
                 service 
               
               
                 manufactured 
                 Hole transport 
                 voltage 
                 Brightness 
                 Efficiency 
                 Luminous 
                 life 
               
               
                 elements 
                 layer 
                 (V) 
                 (cd/m 2 ) 
                 (cd/A) 
                 color 
                 (hr) 
               
               
                   
               
             
            
               
                 Comparative 
                 Comparative 
                 7.01 
                 2645 
                 5.29 
                 Blue 
                 258 
               
               
                 Example 1 
                 Example 
               
               
                   
                 Compound C1 
               
               
                   
                 (NPB) 
               
               
                 Comparative 
                 Comparative 
                 4.73 
                 3170 
                 6.34 
                 Blue 
                 283 
               
               
                 Example 2 
                 Example 
               
               
                   
                 Compound C2 
               
               
                 Comparative 
                 Comparative 
                 6.94 
                 2980 
                 5.96 
                 Blue 
                 213 
               
               
                 Example 3 
                 Example 
               
               
                   
                 Compound C3 
               
               
                 Example 1 
                 Compound 15 
                 4.52 
                 3700 
                 7.40 
                 Blue 
                 353 
               
               
                 Example 2 
                 Compound 18 
                 4.44 
                 3600 
                 7.00 
                 Blue 
                 345 
               
               
                 Example 3 
                 Compound 29 
                 4.33 
                 3475 
                 6.95 
                 Blue 
                 399 
               
               
                 Example 4 
                 Compound 30 
                 4.27 
                 3675 
                 7.35 
                 Blue 
                 359 
               
               
                 Example 5 
                 Compound 43 
                 4.23 
                 3725 
                 7.45 
                 Blue 
                 355 
               
               
                 Example 6 
                 Compound 48 
                 4.46 
                 3620 
                 7.24 
                 Blue 
                 350 
               
               
                 Example 7 
                 Compound 53 
                 4.40 
                 3615 
                 7.23 
                 Blue 
                 348 
               
               
                 Example 8 
                 Compound 60 
                 4.30 
                 3735 
                 7.47 
                 Blue 
                 376 
               
               
                 Example 9 
                 Compound 71 
                 4.41 
                 3780 
                 7.56 
                 Blue 
                 375 
               
               
                 Example 10 
                 Compound 74 
                 4.40 
                 3890 
                 7.78 
                 Blue 
                 360 
               
               
                 Example 11 
                 Compound 85 
                 4.15 
                 3725 
                 7.45 
                 Blue 
                 340 
               
               
                 Example 12 
                 Compound 89 
                 4.32 
                 3550 
                 7.10 
                 Blue 
                 372 
               
               
                 Example 13 
                 Compound 213 
                 4.15 
                 3625 
                 7.25 
                 Blue 
                 365 
               
               
                 Example 14 
                 Compound 217 
                 4.43 
                 3800 
                 7.60 
                 Blue 
                 355 
               
               
                 Example 15 
                 Compound 227 
                 4.52 
                 3725 
                 7.45 
                 Blue 
                 350 
               
               
                 Example 16 
                 Compound 231 
                 4.41 
                 3775 
                 7.55 
                 Blue 
                 350 
               
               
                   
               
            
           
         
       
     
     Referring to Table 2, it can be seen that the light emitting elements of Examples 1 to 16 have a decrease in driving voltage, and have an improvement in brightness and efficiency compared to the light emitting elements of Comparative Examples 1 to 3. In addition, it can be seen that the light emitting elements of Examples 1 to 16 have significantly longer service lives compared to the light emitting elements of Comparative Examples 1 to 3. The light emitting elements of Examples 1 to 16 include, in the hole transport layer, Compounds 15, 18, 29, 30, 43, 48, 53, 60, 71, 74, 85, 89, 213, 217, 227, and 231, respectively, which are the amine compounds of the examples. The amine compound of an example includes a pentacyclic fused ring containing an acridine moiety and an amine group directly or indirectly bonded to the pentacyclic fused ring. Accordingly, the light emitting element including the amine compound of an example may exhibit characteristics in which the driving voltage is reduced, and the brightness, efficiency, and service life are improved. 
     The light emitting element of Comparative Example 1 includes Comparative Example Compound C1, which corresponds to NPB. The light emitting element of Comparative Example 2 includes Comparative Example Compound C2, which includes an acridine moiety, but two phenyl groups bonded to the acridine moiety are not fused. The light emitting element of Comparative Example 3 includes Comparative Example Compound C3, which includes a pentacyclic fused ring in which two rings are further fused to the acridine moiety, but does not include an amine group. Therefore, it is believed that the light emitting elements of Comparative Examples 1 to 3 have no decrease in driving voltage and no improvement in brightness, efficiency, and service life. 
     Provided is a light emitting element including a first electrode, a second electrode on the first electrode, and at least one functional layer between the first electrode and the second electrode. The at least one functional layer may include the amine compound of an embodiment. 
     The amine compound of an example may include a pentacyclic fused ring containing an acridine moiety and an amine group directly or indirectly bonded to the pentacyclic fused ring. Accordingly, the amine compound of an example may contribute to improving a hole transport property and improving the driving voltage, brightness, efficiency, and service life of the light emitting element. The light emitting element including the amine compound of an example may exhibit characteristics in which the driving voltage is reduced, and the brightness, efficiency, and service life are excellent. 
     A light emitting element of an embodiment includes an amine compound of an embodiment, and thus, may exhibit characteristics such that the driving voltage is reduced, the brightness and efficiency are improved, and a service life is excellent. 
     An amine compound of an embodiment may contribute to reducing the driving voltage of the light emitting element, improving the brightness and efficiency, and improving a service life. 
     Although the subject matter of the present disclosure has been described with reference to example embodiments of the present disclosure, it will be understood that the present disclosure should not be limited to these example embodiments but various changes and modifications can be made by those skilled in the art without departing from the spirit and scope of the present disclosure. 
     Accordingly, the technical scope of the present disclosure is not intended to be limited to the contents set forth in the detailed description of the specification, but is intended to be defined by the appended claims, and equivalents thereof.