Patent Publication Number: US-2022235071-A1

Title: Luminescence device and polycyclic compound for luminescence device

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims priority to and benefits of Korean Patent Application No. 10-2021-0005555 under 35 U.S.C. § 119, filed on Jan. 14, 2021 in the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     1. Technical Field 
     The disclosure relates to a luminescence device and a polycyclic compound for the luminescence device. 
     2. Description of the Related Art 
     Active development continues for a luminescence device as an image display apparatus. In contrast to a liquid crystal display apparatus, etc., the luminescence device is a so-called self-luminescent display in which holes and electrons respectively injected from a first electrode and a second electrode recombine in an emission layer, so that a luminescent material including an organic compound in the emission layer emits light to achieve display. 
     In the application of a luminescence device to an image display apparatus, there is a demand for a luminescence device having low driving voltage, high luminous efficiency, and a long service life, and continuous development is required on materials for a luminescence device which is capable of stably achieving such characteristics. 
     It is to be understood that this background of the technology section is, in part, intended to provide useful background for understanding the technology. However, this background of the technology section may also include ideas, concepts, or recognitions that were not part of what was known or appreciated by those skilled in the pertinent art prior to a corresponding effective filing date of the subject matter disclosed herein. 
     SUMMARY 
     The disclosure provides a luminescence device having high efficiency and a polycyclic compound included in a hole transport region of the luminescence device. 
     An embodiment provides a polycyclic compound which may be represented by Formula 1 below: 
     
       
         
         
             
             
         
       
     
     In Formula 1 above, X 1  may be O or S, Ar 1  may be 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, except that Ar 1  is not a heteroaryl group containing two or more nitrogen (N) atoms, R 1  may be a hydrogen atom, a deuterium atom, a halogen atom, or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, R 2  may be a hydrogen atom, a deuterium atom, a halogen 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, or may be bonded to an adjacent group to form a ring, a may be an integer from 0 to 4, b may be an integer from 0 to 3, L may be a direct linkage, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, except that L does not include a carbazole group, and A may be a group represented by Formula 2-1 or Formula 2-2 below, except that L is not a direct linkage when A is a group represented by Formula 2-2 below: 
     
       
         
         
             
             
         
       
     
     In Formula 2-1 and Formula 2-2 above, Y may be N(Ar 3 ), O, or S, X 2  may be O or S, Ar 2  and Ar 3  may each independently be 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, except that Ar 2  and Ar 3  are each not a heteroaryl group containing two or more nitrogen (N) atoms, R 3  to R 5  may each independently be a hydrogen atom, a deuterium atom, a halogen 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, or may be bonded to an adjacent group to form a ring, R 6  may be a hydrogen atom, a deuterium atom, a halogen atom, or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, c and e may each independently be an integer from 0 to 3, and d and f may each independently be an integer from 0 to 4. In Formula 2-1 and Formula 2-2,   represents a binding site to a neighboring atom. 
     In an embodiment, the polycyclic compound represented by Formula 1 above may be represented by any one of Formula 3-1 to Formula 3-3 below: 
     
       
         
         
             
             
         
       
     
     In Formula 3-1 and Formula 3-3 above, R 1  to R 4 , L, Ar 1 , Ar 3 , and a to d may be the same as defined in connection with Formula 1, Formula 2-1, and Formula 2-2. 
     In an embodiment, the polycyclic compound represented by Formula 1 above may be represented by any one of Formula 4-1 to Formula 4-3 below. 
     
       
         
         
             
             
         
       
     
     In Formula 4-1 and Formula 4-3 above, R 1  to R 4 , L, Ar 1 , Ar 3 , and a to d may be the same as defined in connection with Formula 1, Formula 2-1, and Formula 2-2. 
     In an embodiment, the polycyclic compound represented by Formula 1 above may be represented by any one of Formula 5-1 to Formula 5-3 below. 
     
       
         
         
             
             
         
       
     
     In Formula 5-1 to Formula 5-3 above, R 1 , R 2 , R 5 , R 6 , L, Ar 1 , Ar 2 , a, b, e, and f may be the same as defined in connection with Formula 1, Formula 2-1, and Formula 2-2. 
     In an embodiment, the polycyclic compound represented by Formula 1 above may be represented by Formula 6 below: 
     
       
         
         
             
             
         
       
     
     In Formula 6 above, R 7  may be a hydrogen atom, a deuterium atom, a halogen 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, g may be an integer from 0 to 5, and R 1  to R 3 , L, Ar 1 , Y, X 1 , and a to c may be the same as defined in connection with Formula 1, Formula 2-1, and Formula 2-2. 
     In an embodiment, the polycyclic compound represented by Formula 1 above may be represented by any one of Formula 7-1 to Formula 7-3 below: 
     
       
         
         
             
             
         
       
     
     In Formula 7-1 and Formula 7-3 above, R 1  to R 3 , L, Ar 1 , Y, X 1 , and a to c may be the same as defined in connection with Formula 1, Formula 2-1, and Formula 2-2. 
     In an embodiment, R 1  above may be a hydrogen atom or a deuterium atom. 
     In an embodiment, Ar 1 , Ar 2 , and Ar 3  above may be each independently a substituted or unsubstituted phenyl group. 
     In an embodiment, L above may be a direct linkage, a substituted or unsubstituted arylene group having 6 to 18 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 6 to 12 ring-forming carbon atoms, except that L may not include a carbazole group. 
     In an embodiment, L above may be a direct linkage, or may be a group represented by any one of L-1 to L-4 below: 
     
       
         
         
             
             
         
       
     
     In L-1 to L-4 above, X 3  may be O or S, R 8  may be a hydrogen atom, a deuterium atom, a halogen 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, p may be an integer from 0 to 4, and   represents a binding site to a neighboring atom. 
     In an embodiment, the polycyclic compound represented by Formula 1 above may be at least one selected from Compound Group 1. 
     In an embodiment, a luminescence device may include a first electrode, a hole transport region disposed on the first electrode, an emission layer disposed on the hole transport region, an electron transport region disposed on the emission layer, and a second electrode disposed on the electron transport region, wherein the hole transport region may include a polycyclic compound represented by Formula 1 above. 
     In an embodiment, the hole transport region may include a hole injection layer disposed on the first electrode, and a hole transport layer disposed on the hole injection layer, wherein the hole transport layer may include the polycyclic compound represented by Formula 1 above. 
     In an embodiment, the hole transport region may include a hole transport layer disposed on the first electrode, and an electron blocking layer disposed on the hole transport layer, wherein the electron blocking layer may include the polycyclic compound represented by Formula 1 above. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the embodiments, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the disclosure and principles thereof. The above and other aspects and features of the disclosure will become more apparent by describing in detail embodiments thereof with reference to the attached drawings, in which: 
         FIG. 1  is a plan view illustrating a display apparatus according to an embodiment; 
         FIG. 2  is a schematic cross-sectional view illustrating a display apparatus according to an embodiment; 
         FIG. 3  is a schematic cross-sectional view illustrating a luminescence device according to an embodiment; 
         FIG. 4  is a schematic cross-sectional view illustrating a luminescence device according to an embodiment; 
         FIG. 5  is a schematic cross-sectional view illustrating a luminescence device according to an embodiment; 
         FIG. 6  is a schematic cross-sectional view illustrating a luminescence device according to an embodiment; 
         FIG. 7  is a schematic cross-sectional view illustrating a display apparatus according to an embodiment; and 
         FIG. 8  is a schematic cross-sectional view illustrating a display apparatus according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments are shown. This disclosure may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. 
     In the drawings, the sizes, thicknesses, ratios, and dimensions of the elements may be exaggerated for ease of description and for clarity. Like numbers refer to like elements throughout. 
     In the description, it will be understood that when an element (or region, layer, part, etc.) is referred to as being “on”, “connected to”, or “coupled to” another element, it can be directly on, connected to, or coupled to the other element, or one or more intervening elements may be present therebetween. In a similar sense, when an element (or region, layer, part, etc.) is described as “covering” another element, it can directly cover the other element, or one or more intervening elements may be present therebetween. 
     In the description, when an element is “directly on,” “directly connected to,” or “directly coupled to” another element, there are no intervening elements present. For example, “directly on” may mean that two layers or two elements are disposed without an additional element such as an adhesion element therebetween. 
     As used herein, the expressions used in the singular such as “a,” “an,” and “the,” are intended to include the plural forms as well, unless the context clearly indicates otherwise. 
     As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. For example, “A and/or B” may be understood to mean “A, B, or A and B.” The terms “and” and “or” may be used in the conjunctive or disjunctive sense and may be understood to be equivalent to “and/or”. 
     The term “at least one of” is intended to include the meaning of “at least one selected from” for the purpose of its meaning and interpretation. For example, “at least one of A and B” may be understood to mean “A, B, or A and B.” When preceding a list of elements, the term, “at least one of,” modifies the entire list of elements and does not modify the individual elements of the list. 
     It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. Thus, a first element could be termed a second element without departing from the teachings of the disclosure. Similarly, a second element could be termed a first element, without departing from the scope of the disclosure. 
     The spatially relative terms “below”, “beneath”, “lower”, “above”, “upper”, or the like, may be used herein for ease of description to describe the relations between one element or component and another element or component as illustrated in the drawings. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the drawings. For example, in the case where a device illustrated in the drawing is turned over, the device positioned “below” or “beneath” another device may be placed “above” another device. Accordingly, the illustrative term “below” may include both the lower and upper positions. The device may also be oriented in other directions and thus the spatially relative terms may be interpreted differently depending on the orientations. 
     The terms “about” or “approximately” as used herein is inclusive of the stated value and means within an acceptable range of deviation for the recited value as determined by one of ordinary skill in the art, considering the measurement in question and the error associated with measurement of the recited quantity (i.e., the limitations of the measurement system). For example, “about” may mean within one or more standard deviations, or within ±20%, ±10%, or ±5% of the stated value. 
     It should be understood that the terms “comprises,” “comprising,” “includes,” “including,” “have,” “having,” “contains,” “containing,” and the like are intended to specify the presence of stated features, integers, steps, operations, elements, components, or combinations thereof in the disclosure, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof. 
     Unless otherwise defined or implied herein, all terms (including technical and scientific terms) used have the same meaning as commonly understood by those skilled in the art to which this disclosure pertains. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and should not be interpreted in an ideal or excessively formal sense unless clearly defined in the specification. 
     Hereinafter, embodiments of the disclosure will be described with reference to the accompanying drawings. 
       FIG. 1  is a plan view illustrating an embodiment of a display apparatus DD.  FIG. 2  is a schematic cross-sectional view of a display apparatus DD according to an embodiment.  FIG. 2  is a schematic cross-sectional view illustrating a part taken along line I-I′ of  FIG. 1 . 
     The display apparatus DD may include a display panel DP and an optical layer PP disposed on the display panel DP. The display panel DP may include luminescence devices ED- 1 , ED- 2 , and ED- 3 . The display apparatus DD may include multiples of each of the luminescence devices ED- 1 , ED- 2 , and ED- 3 . The optical layer PP may be disposed on the display panel DP and may control light reflected at the display panel DP from an external light. The optical layer PP may include, for example, a polarization layer or a color filter layer. Although not shown in the drawing, in an embodiment, the optical layer PP may be omitted from the display apparatus DD. 
     The display panel DP may include a base layer BS, a circuit layer DP-CL provided on the base layer BS, and a display device layer DP-ED. The display device layer DP-ED may include a pixel defining film PDL, the luminescence devices ED- 1 , ED- 2 , and ED- 3  disposed in the pixel defining film PDL, and an encapsulation layer TFE disposed on the luminescence devices ED- 1 , ED- 2 , and ED- 3 . 
     The base layer BS may provide a base surface on which the display device layer DP-ED is disposed. The base layer BS may be a glass substrate, a metal substrate, a plastic substrate, etc. However, embodiments are not limited thereto, and the base layer BS may include an inorganic layer, an organic layer, or a composite material layer. 
     In an embodiment, the circuit layer DP-CL may be disposed on the base layer BS, and the circuit layer DP-CL may include transistors (not shown). Each of the transistors (not shown) 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 luminescence devices ED- 1 , ED- 2 , and ED- 3  of the display device layer DP-ED. 
     Each of the luminescence devices ED- 1 , ED- 2 , and ED- 3  may have a structure of a luminescence device ED of an embodiment according to  FIGS. 3 to 6 , which will be described later. Each of the luminescence devices 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 luminescence devices ED- 1 , ED- 2 , and ED- 3  are disposed in the 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 each provided as a common layer for the entire luminescence devices ED- 1 , ED- 2 , and ED- 3 . However, embodiments are not limited thereto. Although not shown in  FIG. 2 , in an embodiment, the hole transport region HTR and the electron transport region ETR may each be patterned and provided inside the opening OH defined in the pixel defining film PDL. For example, in an embodiment, the hole transport region HTR, the emission layers EML-R, EML-G, and EML-B, and the electron transport region ETR of the luminescence devices ED- 1 , ED- 2 , and ED- 3  may each be patterned by an inkjet printing method and provided. 
     The encapsulation layer TFE may cover the luminescence devices ED- 1 , ED- 2 , and ED- 3 . The encapsulation layer TFE may seal the display device layer DP-ED. The encapsulation layer TFE may be a thin film encapsulation layer. The encapsulation layer TFE may a single layer or a stack of multiple 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 device layer DP-ED from moisture and/or oxygen, and the encapsulation-organic film may protect the display device 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, or the like, but embodiments are not 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 are not limited thereto. 
     The encapsulation layer TFE may be disposed on the second electrode EL 2  and may be disposed to fill the opening OH. 
     Referring to  FIGS. 1 and 2 , the display apparatus 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 each may be a region which emits light generated from the luminescence devices ED- 1 , ED- 2 , and ED- 3 , respectively. The light emitting regions PXA-R, PXA-G, and PXA-B may be spaced apart from each other in 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 may correspond to portions of the pixel defining film PDL. In the specification, each of the light emitting regions PXA-R, PXA-G, and PXA-B may correspond to a pixel. The pixel defining film PDL may separate the luminescence devices ED- 1 , ED- 2 , and ED- 3 . The emission layers EML-R, EML-G and EML-B of the luminescence devices ED- 1 , ED- 2 , and ED- 3  may be disposed in openings OH defined by the pixel defining film PDL and separated from each other. 
     The light emitting regions PXA-R, PXA-G, and PXA-B may be divided into groups according to a color of light generated from each of the luminescence devices ED- 1 , ED- 2 , and ED- 3 . In the display apparatus DD of an embodiment shown in  FIGS. 1 and 2 , three light emitting regions PXA-R, PXA-G, and PXA-B which respectively emit red light, green light, and blue light, are illustrated. For example, the display apparatus 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, which are separated from one another. 
     In the display apparatus DD according to an embodiment, the luminescence devices ED- 1 , ED- 2  and ED- 3  may each emit light having wavelengths different from one another. For example, in an embodiment, the display apparatus DD may include a first luminescence device ED- 1  that emits red light, a second luminescence device ED- 2  that emits green light, and a third luminescence device ED- 3  that emits blue light. For example, 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 apparatus DD may correspond to the first luminescence device ED- 1 , the second luminescence device ED- 2 , and the third luminescence device ED- 3 , respectively. 
     However, embodiments are not limited thereto, and the first to third luminescence devices ED- 1 , ED- 2 , and ED- 3  may emit light in a same wavelength range or at least one luminescence device may emit light in a wavelength range different from the others. For example, the first to third luminescence devices 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 apparatus DD according to an embodiment may be arranged in a stripe form. Referring to  FIG. 1 , the red light emitting regions PXA-R, the green light emitting regions PXA-G, and the blue light emitting regions PXA-B each may be arranged along a second directional axis DR 2 . 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 a similar area, but embodiments are not limited thereto, and the light emitting regions PXA-R, PXA-G, and PXA-B may have different areas from each other according to a wavelength range of emitted light. The areas of the light emitting regions PXA-R, PXA-G, and PXA-B may be areas in a plan view that are defined by the first directional axis DR 1  and the second directional axis DR 2 . 
     The arrangement form of the light emitting regions PXA-R, PXA-G, and PXA-B is not limited to the feature 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 variously combined and provided according to display quality characteristics required in the display apparatus DD. For example, the arrangement form of the light emitting regions PXA-R, PXA-G, and PXA-B may be a PenTile® arrangement form or a diamond arrangement form. 
     In an embodiment, the areas of the light emitting regions PXA-R, PXA-G, and PXA-B may be different in size from each other. For example, in an embodiment, an area of the green light emitting region PXA-G may be smaller than that of the blue light emitting region PXA-B, but embodiments are not limited thereto. 
     Hereinafter,  FIGS. 3 to 6  are each a schematic cross-sectional view illustrating a luminescence device according to embodiments. Each of the luminescence devices 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. 
     The luminescence device ED of an embodiment includes a polycyclic compound of an embodiment, which will be described later, in the hole transport region HTR disposed between the first electrode EL 1  and the second electrode EL 2 . However, embodiments are not limited thereto, and the luminescence device ED of an embodiment may include a compound according to an embodiment, which will be described later, not only in the hole transport region HTR but also in the emission layer EML or electron transport region ETR, which may be among the functional layers disposed between the first electrode EL 1  and the second electrode EL 2 , or in the capping layer CPL disposed on the second electrode EL 2 . 
     In comparison to  FIG. 3 ,  FIG. 4  illustrates a schematic cross-sectional view of a luminescence device 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 comparison to  FIG. 3 ,  FIG. 5  illustrates a schematic cross-sectional view of a luminescence device 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. In comparison to  FIG. 4 ,  FIG. 6  illustrates a schematic cross-sectional view of a luminescence device ED of an embodiment including a capping layer CPL disposed on a second electrode EL 2 . 
     The first electrode EL 1  has conductivity. The first electrode EL 1  may be formed of a metal alloy or a conductive compound. The first electrode EL 1  may be an anode or a cathode. However, embodiments are not limited thereto. In an embodiment, 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. If the first electrode EL 1  is a transmissive electrode, the first electrode EL 1  may be formed using 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, LiF/Al, Mo, Ti, a compound thereof, or a mixture thereof (for example, a mixture of Ag and Mg). In an embodiment, the second electrode EL 2  may have a multilayer structure including a reflective layer or a transflective layer formed of the above-described materials, and a transparent conductive layer 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 are not limited thereto. A thickness of the first electrode EL 1  may be in a range of about 700 Å to about 10,000 Å. For example, the thickness of the first electrode EL 1  may be in a range of about 1,000 Å to about 3,000 Å. 
     The hole transport region HTR is provided on the first electrode EL 1 . The hole transport region HTR may include at least one of a hole injection layer HIL, a hole transport layer HTL, a hole buffer layer (not shown), and an electron blocking layer EBL. A thickness of the hole transport region HTR may be, for example, in a range of about 50 Å to about 15,000 Å. 
     The hole transport region HTR may have a layer formed of a single material, a layer formed of different materials, or a multilayer structure including layers formed 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 embodiments, the hole transport region HTR may have a single layer structure formed of different materials, or a structure in which a hole injection layer HIL/a hole transport layer HTL, a hole injection layer HIL/a hole transport layer HTL/a hole buffer layer (not shown), a hole injection layer HIL/a hole buffer layer (not shown), a hole transport layer HTL/a hole buffer layer, or a hole injection layer HIL/a hole transport layer HTL/an electron blocking layer EBL are stacked in order from the first electrode EL 1 , but embodiments are not limited thereto. 
     The hole transport region HTR in the luminescence device ED of an embodiment includes a polycyclic compound according to an embodiment. 
     In the specification, the term “substituted or unsubstituted” as used herein may mean a group that is substituted or unsubstituted with at least one substituent selected from the group consisting of a deuterium atom, a halogen atom, a cyano group, a nitro group, an amino 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 alkoxy group, a hydrocarbon ring group, an aryl group, and a heterocyclic group. Each of the substituents listed above may themselves be substituted or unsubstituted. For example, a biphenyl group may be interpreted as an aryl group or as a phenyl group substituted with a phenyl group. 
     In the specification, the term “bonded to an adjacent group to form a ring” may mean a group that is bonded to an adjacent group to form a substituted or unsubstituted hydrocarbon ring, or a substituted or unsubstituted heterocycle. The hydrocarbon ring may include an aliphatic hydrocarbon ring and an aromatic hydrocarbon ring. The heterocycle may include an aliphatic heterocycle and an aromatic heterocycle. The hydrocarbon ring and the heterocycle may each be monocyclic or polycyclic. A ring formed by groups 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 bonded 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. For example, two methyl groups in 4,5-dimethylphenanthrene may be interpreted as “adjacent groups” to each other. 
     In the specification, examples of a halogen atom may include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. 
     In the specification, an alkyl group may be a linear, a branched, or a cyclic type. The number of carbon atoms in the alkyl group may be 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, a s-butyl group, a t-butyl group, an i-butyl group, a 2-ethylbutyl group, a 3,3-a 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 are not limited thereto. 
     In the specification, an alkenyl group may be a hydrocarbon group that includes at least one carbon double bond in the middle or end of an alkyl group having 2 or more carbon atoms. The alkenyl group may be a linear chain or a branched chain. The number of carbon atoms is not specifically limited, but may be 2 to 30, 2 to 20 or 2 to 10. Examples of the alkenyl group may 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. 
     In the specification, an alkynyl group may be a hydrocarbon group including at least one carbon triple bond in the middle or end of an alkyl group having 2 or more carbon atoms. The alkynyl group may be a linear chain or a branched chain. The number of carbon atoms is not specifically limited, but may be 2 to 30, 2 to 20 or 2 to 10. Examples of the alkynyl group may include an ethynyl group, a propynyl group, etc., without limitation. 
     In the specification, a hydrocarbon ring group may be any functional group or substituent derived from an aliphatic hydrocarbon ring, or an any functional group or substituent derived from an aromatic hydrocarbon ring. The number of ring-forming carbon atoms in the hydrocarbon ring group may be 5 to 60, 5 to 30, or 5 to 20. 
     In the specification, an aryl group may be 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 quingphenyl group, a sexiphenyl group, a triphenylenyl group, a pyrenyl group, a benzofluoranthenyl group, a chrysenyl group, etc., but embodiments are not limited thereto. 
     In the specification, a fluorenyl group may be substituted, and two substituents may be combined with each other to form a spiro structure. Examples of substituted fluorenyl groups are as follows. However, embodiments are not limited thereto. 
     
       
         
         
             
             
         
       
     
     In the specification, a heterocyclic group may be any functional group or substituent derived from a ring containing at least one of B, O, N, P, Si, and S as a heteroatom. The heterocyclic group may be an aliphatic heterocyclic group or an aromatic heterocyclic group. The aromatic heterocyclic group may be a heteroaryl group. The aliphatic heterocyclic group and the aromatic heterocyclic group may each be monocyclic or polycyclic. 
     In the specification, a heterocyclic group may include at least one of B, O, N, P, Si, and S as a heteroatom. 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 the heterocyclic group may be 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, an aliphatic heterocyclic group may include at least one of B, O, N, P, Si, and S as a heteroatom. The number of ring-forming carbon atoms in the aliphatic heterocyclic group may be 2 to 30, 2 to 20, or 2 to 10. Examples of the aliphatic heterocyclic group may include an oxirane group, a tyran group, a pyrrolidine group, a piperidine group, a tetrahydrofuran group, a tetrahydrothiophene group, a thian group, a tetrahydropyran group, a 1,4-dioxane group, etc., but embodiments are not limited thereto. 
     In the specification, a heteroaryl group may include at least one of B, O, N, P, Si, and S as a heteroatom. When the heteroaryl group contains two or more heteroatoms, the two or more heteroatoms may be the same as or different from each other. The heteroaryl group may be a monocyclic heteroaryl group or a 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 triazole 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 are not limited thereto. 
     In the specification, the number of carbon atoms in an amine group is not specifically limited, but may be 1 to 30. The amine group may include an alkyl amine group, an aryl amine group, or a heteroaryl amine group. 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 are not limited thereto. 
     In the specification, the above description with respect to the aryl group may be applied to an arylene group, except that the arylene group is a divalent group. 
     In the specification, the above description with respect to the heteroaryl group may be applied to a heteroarylene group, except that the heteroarylene group is a divalent group. 
     In the specification,   and   as used herein each represents a binding site to a neighboring atom. 
     The polycyclic compound according to an embodiment may be represented by Formula 1 below: 
     
       
         
         
             
             
         
       
     
     In Formula 1, X 1  may be O or S. 
     In Formula 1, Ar 1  may be 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, except that Ar 1  is not a heteroaryl group containing two or more nitrogen (N) atoms. 
     In Formula 1, R 1  may be a hydrogen atom, a deuterium atom, a halogen atom, or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms. 
     In Formula 1, R 2  may be a hydrogen atom, a deuterium atom, a halogen 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, or may be bonded to an adjacent group to form a ring. 
     In Formula 1, a may be an integer from 0 to 4, and b may be an integer from 0 to 3. When a is 2 or more, multiple R 1  groups may be the same as or different from each other, and when b is 2 or more, multiple R 2  groups may be the same as or different from each other. 
     In Formula 1, L may be a direct linkage, a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, except that L does not include a carbazole group. 
     In Formula 1, A may be a group represented by Formula 2-1 or Formula 2-2 below. However, L in Formula 1 may not be a direct linkage when A is a group represented by Formula 2-2. 
     
       
         
         
             
             
         
       
     
     In Formula 2-1 and Formula 2-2, Y may be N(Ar 3 ), O, or S, and X 2  may be O or S. 
     In Formula 2-1 and Formula 2-2, Ar 2  and Ar 3  may each independently be 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, except that Ar 2  and Ar 3  are each not a heteroaryl group containing two or more nitrogen (N) atoms. 
     In Formula 2-1 and Formula 2-2, R 3  to R 5  may each independently be a hydrogen atom, a deuterium atom, a halogen 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, or may be bonded to an adjacent group to form a ring. 
     In Formula 2-2, R 6  may be a hydrogen atom, a deuterium atom, a halogen atom, or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms. 
     In Formula 2-1 and Formula 2-2, c and e may each independently be an integer from 0 to 3. When c is 2 or more, multiple R 3  groups may be the same as or different from each other, and when e is 2 or more, multiple R 5  groups may be the same as or different from each other. 
     In Formula 2-1 and Formula 2-2, d and f may each independently be an integer from 0 to 4. When d is 2 or more, multiple R 4  groups may be the same as or different from each other, and when f is 2 or more, multiple R 6  groups may be the same as or different from each other. 
     In an embodiment, R 1  in Formula 1 may be a hydrogen atom or a deuterium atom. 
     In an embodiment, Ar 1 , Ar 2 , and Ar 3  in Formula 1 may each independently be a substituted or unsubstituted phenyl group. 
     In an embodiment, L in Formula 1 may be a direct linkage, a substituted or unsubstituted arylene group having 6 to 18 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 6 to 12 ring-forming carbon atoms. However, L may not include a carbazole group. 
     In an embodiment, X 1  in Formula 1 may be O, and A in Formula 1 may be a group represented by Formula 2-1. In an embodiment, the polycyclic compound represented by Formula 1 may be represented by any one of Formula 3-1 to Formula 3-3 below: 
     
       
         
         
             
             
         
       
     
     In Formula 3-1 to Formula 3-3, R 1  to R 4 , L, Ar 1 , Ar 3 , and a to d may be the same as defined in connection with Formula 1 and Formula 2-1. 
     In an embodiment, X 1  in Formula 1 may be S, and A in Formula 1 may be a group represented by Formula 2-1. In an embodiment, the polycyclic compound represented by Formula 1 may be represented by any one of Formula 4-1 to Formula 4-3 below: 
     
       
         
         
             
             
         
       
     
     In Formula 4-1 to Formula 4-3, R 1  to R 4 , L, Ar 1 , Ar 3 , and a to d may be the same as defined in connection with Formula 1 and Formula 2-1. 
     In an embodiment, in any one Formula among Formula 3-1 to Formula 3-3 and Formula 4-1 to Formula 4-3, L may be a direct linkage, or L may be a group represented by any one of L-1 to L-4 below: 
     
       
         
         
             
             
         
       
     
     In L-1 to L-3, R 8  may be a hydrogen atom, a deuterium atom, a halogen 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 L-1 to L-3, p may be an integer from 0 to 4. When p is 2 or more, multiple R 8  groups may be the same as or different from each other. 
     In L-4, X 3  may be O or S. 
     In an embodiment, A in Formula 1 may be a group represented by Formula 2-2. In an embodiment, the polycyclic compound represented by Formula 1 may be represented by any one of Formula 5-1 to Formula 5-3 below: 
     
       
         
         
             
             
         
       
     
     In Formula 5-1 to Formula 5-3, in an embodiment, L may be a substituted or unsubstituted arylene group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, except that L may not include a carbazole group. 
     In Formula 5-1 to Formula 5-3, R 1 , R 2 , R 5 , R 6 , L, Ar 1 , Ar 2 , a, b, e, and f may be the same as defined in connection with Formula 1 and Formula 2-2. 
     In an embodiment, in any one Formula among Formula 5-1 to Formula 5-3, L may be a group represented by any one of L-1 to L-4 below: 
     
       
         
         
             
             
         
       
     
     In L-1 to L-3, R 8  may be a hydrogen atom, a deuterium atom, a halogen 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 L-1 to L-3, p may be an integer of 0 to 4. When p is 2 or more, multiple R 8  groups may be the same as or different from each other. 
     In L-4, X 3  may be O or S. 
     In an embodiment, the polycyclic compound represented by Formula 1 may be represented by Formula 6 below: 
     
       
         
         
             
             
         
       
     
     In Formula 6, R 7  may be a hydrogen atom, a deuterium atom, a halogen 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 6, g may be an integer from 0 to 5. When g is 2 or more, multiple R 7  groups may be the same as or different from each other. 
     In Formula 6, R 1  to R 3 , L, Ar 1 , Y, X 1 , and a to c may be the same as defined in connection with Formula 1 and Formula 2-1. 
     In an embodiment, the polycyclic compound represented by Formula 1 may be represented by any one of Formula 7-1 to Formula 7-3 below: 
     
       
         
         
             
             
         
       
     
     In Formula 7-1 and Formula 7-3, R 1  to R 3 , L, Ar 1 , Y, X 1 , and a to c may be the same as defined in connection with Formula 1 and Formula 2-1. 
     The polycyclic compound represented by Formula 1 according to an embodiment may be any one selected from Compound Group 1 below. However, embodiments are not limited thereto. 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     A luminescence device ED according to an embodiment will be further described with reference to  FIGS. 3 to 6 . 
     As described above, the hole transport region HTR includes a polycyclic compound according to an embodiment as described above. For example, the hole transport region HTR may include the polycyclic compound represented by Formula 1. 
     When the hole transport region HTR includes multiple layers, any of the layers may include a polycyclic compound represented by Formula 1. For example, in an embodiment, the hole transport region HTR may include a hole injection layer HIL disposed on the first electrode EL 1  and a hole transport layer HTL disposed on the hole injection layer, wherein the hole transport layer HTL may include a polycyclic compound represented by Formula 1. However, embodiments are not limited thereto, and, for example, the hole injection layer HIL may include a polycyclic compound represented by Formula 1. For example, in another embodiment, the hole transport region HTR may include a hole transport layer HTL disposed on the first electrode EL 1  and an electron blocking layer EBL disposed on the hole transport layer, wherein the electron blocking layer EBL may include a polycyclic compound represented by Formula 1. 
     The hole transport region HTR may include one or two or more of polycyclic compounds represented by Formula 1. For example, the hole transport region HTR may include at least one selected from Compound Groups 1 as described above. 
     The hole transport region HTR may be formed using various 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 a laser induced thermal imaging (LITI) method. 
     The hole transport region HTR may further include a compound represented by Formula H-1 below: 
     
       
         
         
             
             
         
       
     
     In Formula H-1 above, L a1  and L a2  may each independently 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. In Formula H-1, a-1 and b-1 may each independently be an integer from 0 to 10. In Formula H-1, when a-1 or b-1 is 2 or more, multiple L a1  groups and multiple L a2  groups may each independently be 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 a1  to Ar a3  may each independently be 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 compound represented by Formula H-1 above may be a monoamine compound. In another embodiment, the compound represented by Formula H-1 above may be a diamine compound in which at least one of Ar a1  to Ar a3  includes an amine group as a substituent. For example, the compound represented by Formula H-1 above may be a carbazole-based compound including a substituted or unsubstituted carbazole group in at least one of Arai and Ar a2 , or a fluorene-based compound including a substituted or unsubstituted fluorene group in at least one of Ar a1  and Ar a2 . 
     The compound represented by Formula H-1 may be any one selected from 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 listed in Compound Group H below: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     The hole transport region HTR may 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(1-naphthyl)-N-phenylamino]-triphenylamine (1-TNATA), 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-1-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), etc. 
     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-1-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), 1,3-bis(N-carbazolyl)benzene (mCP), etc. 
     The hole transport region HTR may further include 9-(4-tert-butylphenyl)-3,6-bis(triphenylsilyl)-9H-carbazole (CzSi), 9-phenyl-9H-3,9′-bicarbazole (CCP), 1,3-bis(1,8-dimethyl-9H-carbazol-9-yl)benzene (mDCP), etc. 
     The hole transport region HTR may include the above-described compound of the hole transport region in at least one of a hole injection layer HIL, a hole transport layer HTL, and an electron blocking layer EBL. 
     A thickness of the hole transport region HTR may be in a range of about 100 Å to about 10,000 Å. For example, the thickness of the hole transport region HTR may be in a range of about 100 Å to about 5,000 Å. A thickness of the hole injection layer HIL may be, for example, in a range of about 30 Å to about 1,000 Å, and a thickness of the hole transport layer HTL may be in a range of about 30 Å to about 1,000 Å. For example, a thickness of the electron blocking layer EBL may be in a range 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, satisfactory hole transport characteristic may be achieved without a substantial increase in a driving voltage. 
     The hole transport region HTR may further include a charge generating material to increase 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 quinone derivatives, metal oxides, and cyano group-containing compounds, but embodiments are not limited thereto. For example, non-limiting examples of the p-dopant may include quinone derivatives such as tetracyanoquinodimethane (TCNQ) and 2,3,5,6-tetrafluoro-7,7′8,8-tetracyanoquinodimethane (F4-TCNQ), metal oxides such as tungsten oxide and molybdenum oxide, etc., but embodiments are not limited thereto. 
     As described above, the hole transport region HTR may further include at least one of a hole buffer layer (not shown) and an electron blocking layer EBL in addition to the hole injection layer HIL and the hole transport layer HTL. The hole buffer layer (not shown) may compensate for a resonance distance according to a wavelength of light emitted from the emission layer EML, and may thus increase luminous efficiency. Materials which may be included in the hole transport region HTR may be used as materials to be included in the hole buffer layer (not shown). The electron blocking layer EBL may prevent electron injection 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, for example, in a range of about 100 Å to about 1,000 Å. For example, the emission layer EML may have a thickness in a range of about 100 Å to about 300 Å. The emission layer EML may have a layer formed of a single material, a layer formed of different materials, or a multilayer structure having layers formed of different materials. 
     In the luminescence device ED of an embodiment, the emission layer EML may include anthracene derivatives, pyrene derivatives, fluoranthene derivatives, chrysene derivatives, dihydrobenzanthracene derivatives, or triphenylene derivatives. For example, in an embodiment, the emission layer EML may include anthracene derivatives or pyrene derivatives. 
     In each luminescence device ED of embodiments illustrated in  FIGS. 3 to 6 , the emission layer EML may include a host and a dopant, and 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 fluorescence host material. 
     
       
         
         
             
             
         
       
     
     In Formula E-1, R 31  to R 40  may each independently be 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 1 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. In Formula E-1, 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. 
     In Formula E-1, c and d may each independently be an integer from 0 to 5. 
     The compound represented by Formula E-1 may be any one selected from 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 phosphorescence host material. 
     
       
         
         
             
             
         
       
     
     In Formula E-2a, a may be an integer from 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 2 or more, multiple L a  groups may each independently be 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-2a, A 1  to A 5  may each independently be N or C(R i ). R a  to R i  may each independently be 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 of A 1  to A 5  may be N, and the remainder of A 1  to A 5  may be C(R i ). 
     
       
         
         
             
             
         
       
     
     In Formula E-2b, Cbz 1  and Cbz 2  may each independently be an unsubstituted carbazole group, or a carbazole group substituted with an aryl group having 6 to 30 ring-forming carbon atoms. L b  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. In Formula E-2b, b may be an integer from 0 to 10. When b is 2 or more, multiple L b  groups may each independently be 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 any one selected from Compound Group E-2 below. However, the compounds listed in Compound Group E-2 below are only examples, and the compound represented by Formula E-2a or Formula E-2b is not limited to those listed in Compound Group E-2 below. 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     The emission layer EML may further include a general material in the art as a host material. For example, the emission layer EML may include, as a host material, at least one of 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), and 1,3,5-tris(1-phenyl-1H-benzo[d]imidazole-2-yl)benzene (TPBi). However, embodiments are not limited thereto, and 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 each independently be C(R 1 ) or N, R 1  to R 4  may each independently be 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 may be 0 or 1, and n may be 2 or 3. In Formula M-a, when m is 0, n may be 3, and when m is 1, n may be 2. 
     The compound represented by Formula M-a may be used as a phosphorescence dopant. 
     The compound represented by Formula M-a may be any one selected from 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 Compounds M-a1 to M-a25 below. 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     Compound M-a1 and Compound M-a2 may be used as a red dopant material, and Compound M-a3 and Compound M-A4 may be used as a green dopant material. 
     
       
         
         
             
             
         
       
     
     In Formula M-b, Q 1  to Q 4  may each independently be C or N, and C1 to C4 may each independently be 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 M-b, L 21  to L 24  may each independently be 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, and el to e4 may each independently be 0 or 1. In Formula M-b, R 31  to R 39  may each independently be 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, or may be bonded to an adjacent group to form a ring, and d1 to d4 may each independently be an integer from 0 to 4. 
     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 any one selected from the compounds below. However, the compounds below are examples, and the compound represented by Formula M-b is not limited to the compounds below. 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     In the compounds, R, R 38 , and R 39  may each independently be 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 of Formula F-a to Formula F-c below. The compound represented by Formula F-a to Formula F-c below may be used as a fluorescence dopant material. 
     
       
         
         
             
             
         
       
     
     In Formula F-a, two selected from R a  to R j  may each independently be substituted with 
     
       
         
         
             
             
         
       
     
     The remainder of R a  to R j  which are not substituted with 
     
       
         
         
             
             
         
       
     
     may each independently be 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 the group 
     
       
         
         
             
             
         
       
     
     Ar 1  and Ar 2  may each independently be 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  and Ar 2  may be a heteroaryl group containing O or S as a ring-forming atom. 
     
       
         
         
             
             
         
       
     
     In Formula F-b, R a  and R b  may each independently be 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. 
     In Formula F-b, U and V may each independently be 0 or 1. If Formula F-b, U indicates the number of rings fused at the position of U, and V indicates the number of rings fused at the position of V. For example, when U or V is 1, a ring indicated by U or V may form a condensed ring, and when U or V is 0, a ring indicated by U or V may not be present. When U is 0 and V is 1, or when U is 1 and V is 0, the condensed ring having a fluorene core of Formula F-b may be a four-ring cyclic compound. When both U and V are 0, the condensed ring of Formula F-b may be a three-ring cyclic compound. When both U and V are 1, the condensed ring having a fluorene core of Formula F-b may be a five-ring cyclic compound. 
     In Formula F-b, when U or V is 1, U and V may each independently be 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-c, A 1  and A 2  may each independently be O, S, Se, or N(R 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 each independently be 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 N(R m ), A 1  may be bonded to R 4  or R 5  to form a ring. For example, A 2  may be bonded to R 7  or R 8  to form a ring. 
     In an embodiment, the emission layer EML may include, as dopant materials, styryl derivatives (e.g., 1,4-bis[2-(3-N-ethylcarbazoryl)vinyl]benzene (BCzVB), 4-(di-p-tolylamino)-4′-[(di-p-tolylamino)styryl]stilbene (DPAVB), and N-(4-((E)-2-(6-((E)-4-(diphenylamino)styryl)naphthalen-2-yl)vinyl)phenyl)-N-phenylbenzenamine (N-BDAVBi), perylene and the derivatives thereof (e.g., 2,5,8,11-tetra-t-butylperylene (TBP)), pyrene and the derivatives thereof (e.g., 1-dipyrene, 1,4-dipyrenylbenzene, 1,4-bis(N,N-diphenylamino)pyrene), etc. 
     The emission layer EML may include a phosphorescence dopant material. For example, a metal complex including 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 phosphorescence dopant. For example, iridium(III) bis(4,6-difluorophenylpyridinato-N,C2′)picolinate (FIrpic), bis(2,4-difluorophenylpyridinato)-tetrakis(1-pyrazolyl)borate iridium(III) (Fir6), or platinum octaethyl porphyrin (PtOEP) may be used as a phosphorescence dopant. However, embodiments are not limited thereto. 
     The emission layer EML may include a quantum dot material. The quantum dot may be selected from among a Group II-VI compound, a Group III-VI compound, a Group I-III-VI 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. 
     A 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 In 2 Se 3 , a ternary compound such as InGaS 3  and InGaSe 3 , or any combination thereof. 
     A 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 , and a mixture thereof, or a quaternary compound such as AgInGaS 2  and 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. 
     A binary compound, a ternary compound, or a quaternary compound may be present in particles at a uniform concentration distribution, or may be present in the same particle at a partially different concentration distribution. In an embodiment, the quantum dot may have a core/shell structure in which one quantum dot surrounds another quantum dot. An interface between the core and the shell may have a concentration gradient in which the concentration of an element that is present in the shell decreases towards the core. 
     In embodiments, a 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 be a protection layer that prevents the chemical deformation of the core so as to maintain semiconductor properties, and/or may be 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 or non-metal oxide, a semiconductor compound, or a combination thereof. 
     For example, the metal 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 NiO, or a ternary compound such as MgAl 2 O 4 , CoFe 2 O 4 , NiFe 2 O 4 , and CoMn 2 O 4 , but embodiments are not limited thereto. 
     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 are not limited thereto. 
     The quantum dot may have a full width of half maximum (FWHM) of a light emission wavelength spectrum equal to or less than about 45 nm. For example, the quantum dot may have a FWHM of a light emission wavelength spectrum equal to or less than about 40 nm. For example, the quantum dot may have a FWHM of a light emission wavelength spectrum equal to or less than about 30 nm. Color purity and/or color reproducibility may be improved in the above ranges. Light emitted through such a quantum dot may be emitted in all directions, and thus a wide viewing angle may be improved. 
     The form of a quantum dot is not particularly limited and may be a form commonly used in the art. For example, a quantum dot may have a spherical, a pyramidal, a multi-arm, or a cubic shape, or the quantum dot may be in the form of nanoparticles, nanotubes, nanowires, nanofibers, nanoparticles, etc. 
     The quantum dot may control the color of emitted light according to the particle size thereof. Accordingly, the quantum dot may have various light emission colors such as blue, red, and green. 
     In each luminescence device ED of embodiments illustrated in  FIGS. 3 to 6 , the electron transport region ETR is provided on the emission layer EML. The electron transport region ETR may include at least one of a hole blocking layer HBL, an electron transport layer ETL, or an electron injection layer EIL, but embodiments are not limited thereto. 
     The electron transport region ETR may have a layer formed of a single material, a layer formed of different materials, or a multilayer structure including layers formed 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 embodiments, the electron transport region ETR may have a single layer structure formed of different materials, or may have a structure in which an electron transport layer ETL/an electron injection layer EIL, or a hole blocking layer HBL/an electron transport layer ETL/an electron injection layer EIL are stacked in order from the emission layer E-L, but embodiments are not limited thereto. The electron transport region ETR may have a thickness, for example, in a range of about 1,000 Å to about 1,500 Å. 
     The electron transport region ETR may be formed by using various 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 of X 1  to X 3  may be N, and the remainder of X 1  to X 3  may be C(R 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. In Formula ET-1, Ar 1  to Ar 3  may each independently 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. 
     In Formula ET-1, a to c may each independently be an integer from 0 to 10. In Formula ET-1, L 1  to L 3  may each independently 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. In Formula ET-1, when a to c are 2 or more, L 1  to L 3  may each independently be 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 the electron transport region ETR includes an electron transport layer ETL, the electron transport region ETR may include an anthracene-based compound. However, embodiments are not limited thereto, and the electron transport region 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-biphenylyl)-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 (Bebg 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. 
     The electron transport region ETR may include at least one selected from Compound ET1 to Compound ET36 below: 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     The electron transport regions ETR may include a metal halide such as LiF, NaCl, CsF, RbCl, RbI, CuI, or KI, a lanthanide metal such as Yb, 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, etc. as a co-deposited material. The electron transport region ETR may include a metal oxide such as Li 2 O or BaO, or 8-hydroxyl-lithium quinolate (Liq), etc., but embodiments are not limited thereto. The electron transport region ETR may also be formed of a mixture material of an electron transport material and an insulating organometallic salt. The organometallic salt may be a material having an energy band gap equal to or greater than about 4 eV. For example, the organometallic salt may include metal acetates, metal benzoates, metal acetoacetates, metal acetylacetonates, or metal stearates, but embodiments are not limited thereto. 
     The electron transport region ETR may include the above-described compounds of the hole transport region in at least one of the electron injection layer EIL, the electron transport layer ETL, and the hole blocking layer HBL. 
     When the electron transport region ETR includes an electron transport layer ETL, the electron transport layer ETL may have a thickness in a range of about 100 Å to about 1,000 Å. For example, electron transport layer ETL may have a thickness in a range of about 150 Å to about 500 Å. If the thickness of the electron transport layer ETL satisfies the aforementioned range, satisfactory electron transport characteristics may be obtained without a substantial increase in driving voltage. When the electron transport region ETR includes an electron injection layer EIL, the electron injection layer EIL may have a thickness in a range of about 1 Å to about 100 Å. For example, the electron injection layer EIL may have a thickness in a range of about 3 Å to about 90 Å. If the thickness of the electron injection layer EIL satisfies the above-described range, 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 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 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, L 1 , Ca, LiF/Ca, LiF/Al, Mo, Ti, Yb, W, a compound thereof, or a mixture thereof (e.g., AgMg, AgYb, or MgAg). In an embodiment, 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, or the like. 
     Although not shown in the drawings, the second electrode EL 2  may be electrically connected to an auxiliary electrode. If the second electrode EL 2  is electrically connected to the auxiliary electrode, the resistance of the second electrode EL 2  may decrease. 
     In an embodiment, the luminescence device ED may further include a capping layer CPL disposed on the second electrode EL 2 . The capping layer CPL may include a multilayer or a single layer. 
     In an embodiment, the capping layer CPL may include an organic layer or an inorganic layer. For example, when the capping layer CPL includes an inorganic material, the inorganic material may include an alkaline metal compound such as LiF, an alkaline earth metal compound such as 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 sol-9-yl)triphenylamine (TCTA), etc., or an epoxy resin, or acrylate such as methacrylate. However, embodiments are not limited thereto, and the organic material may also include Compounds P1 to P5 below. 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     A refractive index of the capping layer CPL may be equal to or greater than about 1.6. For example, the refractive index of the capping layer CPL may be equal to or greater than about 1.6 or more with respect to light in a wavelength range of about 550 nm to about 660 nm. 
       FIGS. 7 and 8  each are a schematic cross-sectional view of a display apparatus according to an embodiment. Hereinafter, in describing the display apparatus of an embodiment with reference to  FIGS. 7 and 8 , the features which have been previously described in  FIGS. 1 to 6  will not be described again, but their differences will be described. 
     Referring to  FIG. 7 , the display apparatus DD according to an embodiment may include a display panel DP including a display device layer DP-ED, a light control layer CCL disposed 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 device layer DP-ED, and the display device layer DP-ED may include a luminescence device ED. 
     The luminescence device ED may include a first electrode EL 1 , a hole transport region HTR disposed on the first electrode EL 1 , an emission layer EML disposed on the hole transport region HTR, an electron transport region ETR disposed on the emission layer EIL, and a second electrode EL 2  disposed on the electron transport region ETR. The structures of the luminescence devices of  FIGS. 3 to 6  as described above may be equally applied to the structure of the luminescence device ED shown in  FIG. 7 . 
     Referring to  FIG. 7 , the emission layer EIL may be disposed in an opening OH defined in a pixel defining film PDL. For example, the emission layer EIL, which is divided by the pixel defining film PDL and provided corresponding to each of the light emitting regions PXA-R, PXA-G, and PXA-B, may emit light in a same wavelength range. In the display apparatus DD of an embodiment, the emission layer EIL may emit blue light. Although not shown in the drawings, in an embodiment, the emission layer EIL may be provided as a common layer for all light emitting regions PXA-R, PXA-G, and PXA-B. 
     The light control layer CCL may be disposed on the display panel DP. The light control layer CCL may include a light conversion body. The light conversion body may include a quantum dot, a phosphor, or the like. The light conversion body may convert the wavelength of provided and emit the converted light. For example, the light control layer CCL may be a layer containing the quantum dot or a layer containing the phosphor. 
     The light control layer CCL may include 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 one another. 
     Referring to  FIG. 7 , divided patterns BMP may be disposed between the light control parts CCP 1 , CCP 2 , and CCP 3  which are spaced apart from each other, but embodiments 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 first color light provided from the luminescence device ED into second color light, a second light control part CCP 2  containing a second quantum dot QD 2  which converts the first color light into 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 by the luminescence device 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 with respect to quantum dots may be applied to the quantum dots QD 1  and QD 2 . 
     The light control layer CCL may further include a 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 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 , and hollow silica. The scatterer SP may include any one of TiO 2 , ZnO, Al 2 O 3 , SiO 2 , or hollow 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 silica. 
     The light control layer CCL may include a barrier layer BFL 1 . The barrier layer BFL 1  may prevent the penetration of moisture and/or oxygen (hereinafter, referred to as ‘moisture/oxygen’). The barrier layer BFL 1  may be disposed on the light control parts CCP 1 , CCP 2 , and CCP 3  to block the light control parts CCP 1 , CCP 2 , and CCP 3  from being exposed to moisture/oxygen. The barrier layer BFL 1  may cover the light control parts CCP 1 , CCP 2 , and CCP 3 . In an embodiment, 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. For example, 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 of multiple layers. 
     In the display apparatus DD of an embodiment, the color filter layer CFL may be disposed on the light control layer CCL. For example, the color filter layer CFL may be directly disposed on the light control layer CCL. In an embodiment, the barrier layer BFL 2  may be omitted. 
     The color filter layer CFL may include a light shielding unit BM and filters CF 1 , CF 2 , and CF 3 . The color filter layer CFL may include a first filter CF 1  that transmits the second color light, a second filter CF 2  that transmits the third color light, and a third filter CF 3  that transmits 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 or dye. The first filter CF 1  may include a red pigment or dye, the second filter CF 2  may include a green pigment or dye, and the third filter CF 3  may include a blue pigment or dye. However, embodiments 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. 
     In an embodiment, the first filter CF 1  and the second filter CF 2  may each 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 light shielding unit BM may be a black matrix. The light shielding unit BM may include an organic light shielding material or an inorganic light shielding material containing a black pigment or dye. The light shielding unit BM may prevent light leakage, and may separate boundaries between the adjacent filters CF 1 , CF 2 , and CF 3 . In an embodiment, the light shielding unit BM may be formed of a blue filter. 
     The first to third filters CF 1 , CF 2 , and CF 3  may be disposed corresponding 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 disposed on the color filter layer CFL. The base substrate BL may provide a base surface in which the color filter layer CFL, the light control layer CCL, and the like are disposed. The base substrate BL may be a glass substrate, a metal substrate, a plastic substrate, etc. However, embodiments are not limited thereto, and the base substrate BL may include an inorganic layer, an organic layer, or a composite material layer. Although not shown in the drawing, in an embodiment, the base substrate BL may be omitted. 
       FIG. 8  is a schematic cross-sectional view illustrating a part of a display apparatus according to an embodiment.  FIG. 8  illustrates a schematic cross-sectional view of a part corresponding to the display panel DP of  FIG. 7 . In the display apparatus DD-TD of an embodiment, the luminescence device ED-BT may include light emitting structures OL-B 1 , OL-B 2 , and OL-B 3 . The luminescence device ED-BT may include a first electrode EL 1  and a second electrode EL 2  which face each other, and the light emitting structures OL-B 1 , OL-B 2 , and OL-B 3  sequentially stacked in a 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 ) disposed therebetween. 
     For example, the luminescence device ED-BT included in the display apparatus DD-TD of an embodiment may be a luminescence device having a tandem structure and including multiple emission layers. 
     In an embodiment illustrated in  FIG. 8 , all light respectively emitted from the light emitting structures OL-B 1 , OL-B 2 , and OL-B 3  may be blue light. However, embodiments are not limited thereto, and the light respectively emitted from the light emitting structures OL-B 1 , OL-B 2 , and OL-B 3  may have wavelength ranges different from each other. For example, the luminescence device ED-BT including the light emitting structures OL-B 1 , OL-B 2 , and OL-B 3  which emit light having wavelength ranges different from each other may emit white light. 
     Charge generation layers CGL 1  and CGL 2  may be disposed between 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 each independently include a p-type charge generation layer and/or an n-type charge generation layer. 
     Hereinafter, embodiments will be described through the Examples and Comparative Examples. The Examples below are only illustrations for assisting the understanding of the disclosure, and the scope thereof is not limited thereto. 
     (Synthesis Examples) 
     The polycyclic compound according to an embodiment of the inventive concept may be synthesized as, for example, the following. However, a synthesis method of the polycyclic compound according to an embodiment of the inventive concept is not limited thereto. 
     1. Synthesis of Intermediates A-4 and B-4 
     
       
         
         
             
             
         
       
     
     (1) Synthesis of Intermediates B-1 
     In an Ar atmosphere, in a 500 mL three-neck, B 1  (12.37 g, 50 mmol) and ether (250 mL) were added and cooled to about −78° C., and n-BuLi (74.07 g, 120 mmol) was dropped thereto and stirred for about 1 hour. B(OMe) 3  (15.59 g, 150 mmol) was dropped thereto, and the reaction mixture was returned to room temperature and stirred for about 3 hours. After the reaction, the resulting product was neutralized with 1M HCl, extracted with CH 2 Cl 2 , dried over MgSO 4 , and concentrated. The resulting crude product was purified by silica gel column chromatography to obtain Compound B-1 which is a white solid (7.65 g, yield 72%). 
     By measuring FAB-MS, a mass number of m/z=212 was observed by molecular ion peak, thereby identifying Intermediate B-1. 
     (2) Synthesis of Intermediate B-2 
     In an Ar atmosphere, in a 500 mL three-neck, 2-nitrobromobenzene (7.0 g, 34.6 mmol), Intermediate B-1 (7.36 g, 41.6 mmol), K 3 PO 4  (14.7 g, 69.3 mmol), toluene (138.6 mL), ethanol (69.3 mL), and H 2 O (34.6 mL) were sequentially added and fully bubbled, and at last Pd(PPh 3 ) 4 (1.2 g, 1.04 mmol) was added thereto, and the mixture was heated and stirred at about 80° C. for about 4 hours. After the mixture was air-cooled to room temperature, the reaction solvent was removed by distillation to obtain a crude product. The resulting crude product was purified by silica gel column chromatography to obtain Compound B-2 which is a white solid (7.8 g, yield 78%). 
     By measuring FAB-MS, a mass number of m/z=289 was observed by molecular ion peak, thereby identifying Intermediate B-2. 
     (3) Synthesis of Intermediate B-3 
     In an Ar atmosphere, in a 500 mL three-neck flask, B-2 (7.5 g, 25.9 mmol), PPh 3  (6.8 g, 25.9 mmol), and o-dichlorobenzene (105 mL) were added and stirred under reflux for about 24 hours. The mixture was air-cooled to room temperature, and filtered. The filtrate was concentrated and purified by silica gel column chromatography to obtain Compound B-3 (5.3 g, yield 79%). 
     By measuring FAB-MS, a mass number of m/z=257 was observed by molecular ion peak, thereby identifying Intermediate B-3. 
     (4) Synthesis of Intermediate B-4 
     In an Ar atmosphere in atmosphere, in a 500 mL three-neck flask, Intermediate B-3 (5.0 g, 19.4 mmol), Pd(dba) 2  (0.56 g, 0.05 equiv, 0.97 mmol), NaOtBu (1.86 g, 1 equiv, 19.40 mmol), toluene (194 mL), bromobenzene (3.05 g, 1.1 equiv, 21.34 mmol), and tBu 3 P (0.79 g, 0.2 equiv, 3.88 mmol) were sequentially added and heated and stirred under reflux for about 6 hours. After the mixture was air-cooled to room temperature, the organic layer was fractionated by adding water to the reaction solvent. The organic layer was further extracted by adding toluene to a water layer, and the combined organic layers were washed with saline and dried over MgSO 4 . MgSO 4  was filtered off and the organic layer was concentrated, and the resulting crude product was purified by silica gel column chromatography to obtain Compound B-4 which is a white solid (5.6 g, yield 87%). 
     By measuring FAB-MS, a mass number of m/z=333 was observed by molecular ion peak, thereby identifying Intermediate B-4. 
     (5) Synthesis of Intermediate A-4 
     Intermediate A-4 was synthesized by the same method as the synthesis method of Intermediate B-4 except that A1 was used instead of B 1 . 
     By measuring FAB-MS, a mass number of m/z=371 was observed by molecular ion peak, thereby identifying Compound A-4. 
     2. Synthesis of Compound 1 
     
       
         
         
             
             
         
       
     
     In an Ar atmosphere, in a 200 mL three-neck flask, A-4 (5.0 g, 14.98 mmol), C-1 (3.6 g, 14.98 mmol), Pd(dba) 2  (0.43 g, 0.05 equiv, 0.75 mmol), Cs 2 CO 3  (14.64 g, 3 equiv, 14.98 mmol), and DMF (100 mL) were sequentially added and heated and stirred under reflux at about 130° C. for about 6 hours. After the mixture was air-cooled to room temperature, the organic layer was fractionated by adding water to the reaction solvent. The organic layer was further extracted by adding toluene to a water layer, and the combined organic layers were washed with saline and dried over MgSO 4 . MgSO 4  was filtered off and the organic layer was concentrated, and the resulting crude product was purified by silica gel column chromatography to obtain Compound 1 which is a white solid (5.9 g, yield 75%). 
     By measuring FAB-MS, a mass number of m/z=524 was observed by molecular ion peak, thereby identifying Compound 1. 
     3. Synthesis of Compound 481 
     
       
         
         
             
             
         
       
     
     Compound 481 was synthesized by the same synthesis method as that of Compound 1 except that DBT-1BPin was used instead of C-1. 
     By measuring FAB-MS, a mass number of m/z=465 was observed by molecular ion peak, thereby identifying Compound 481. 
     4. Synthesis of Compound 241 
     
       
         
         
             
             
         
       
     
     Compound 241 was synthesized by the same synthesis method as that of Compound 1 except that 6-Ph-DBF-4BPin was used instead of C-1. 
     By measuring FAB-MS, a mass number of m/z=541 was observed by molecular ion peak, thereby identifying Compound 241. 
     5. Synthesis of Compound 249 
     
       
         
         
             
             
         
       
     
     Compound 249 was synthesized by the same synthesis method as that of Compound 1 except that NaP-DBF-4BPin was used instead of C-1. 
     By measuring FAB-MS, a mass number of m/z=515 was observed by molecular ion peak, thereby identifying Compound 249. 
     6. Synthesis of Compound 551 
     
       
         
         
             
             
         
       
     
     Compound 551 was synthesized by the same synthesis method as that of Compound 1 except that 4-Ph-DBT-3′BPin was used instead of C-1. 
     By measuring FAB-MS, a mass number of m/z=557 was observed by molecular ion peak, thereby identifying Compound 551. 
     7. Synthesis of Compound 855 
     
       
         
         
             
             
         
       
     
     Compound 855 was synthesized by the same synthesis method as that of Compound 1 except that Benzene-1,2-BPin was used instead of C-1. 
     By measuring FAB-MS, a mass number of m/z=640 was observed by molecular ion peak, thereby identifying Compound 855. 
     8. Synthesis of Compound 873 
     
       
         
         
             
             
         
       
     
     Compound 873 was synthesized by the same synthesis method as that of Compound 1 except that DBT-4,4′-BPin was used instead of C-1. 
     By measuring FAB-MS, a mass number of m/z=746 was observed by molecular ion peak, thereby identifying Compound 873. 
     9. Synthesis of Compound 896 
     
       
         
         
             
             
         
       
     
     Compound 896 was synthesized by the same synthesis method as that of Compound 1 except that A4 was used instead of A-4 and 6-DPh-DBF-4-BPin was used instead of C-1. 
     By measuring FAB-MS, a mass number of m/z=535 was observed by molecular ion peak, thereby identifying Compound 896. 
     (Device Manufacturing Examples) 
     Luminescence devices were manufactured using Example Compounds and Comparative Example Compounds below as an emission layer material. 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     The luminescence devices of Examples and Comparative Examples were manufactured by the following method. A 150 nm-thick ITO was patterned on a glass substrate, and the glass substrate was washed with ultrapure water and treated with UV and ozone for about 10 minutes to form a first electrode. 2-TNATA was deposited thereon to have a thickness of about 60 nm, and Example Compound or Comparative Example Compound was used to form a 30 nm-thick hole transport layer. TBP was doped to ADN by 3% to form a 25 nm-thick emission layer, a 25 nm-thick layer was formed with Alq 3  on the emission layer, and a 1 nm-thick layer was formed with LiF to form an electron transport region. A 100 nm-thick second electrode was formed with aluminum (Al). Each layer was formed by a vacuum deposition method. 
     The measured values according to Examples 1 to 8 and Comparative Examples 1 to 6 are shown in Table 1 below. Current efficiency was measured at 10 mA/cm, and a half service life represents a time taken to reduce the brightness to about 500 with respect to an initial brightness of 1,000 cd/m 2 . 
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                   
                 Current 
                 Service 
               
               
                   
                   
                 Voltage 
                 efficiency 
                 life 
               
               
                   
                 Hole transport layer 
                 (V) 
                 (cd/A) 
                 LT50 (h) 
               
               
                   
               
             
            
               
                 Example 1 
                 Example Compound 1  
                 5.7 
                 8.7 
                 2100 
               
               
                 Example 2 
                 Example Compound 481 
                 5.8 
                 8.5 
                 2000 
               
               
                 Example 3 
                 Example Compound 241 
                 5.6 
                 8.4 
                 2250 
               
               
                 Example 4 
                 Example Compound 249 
                 5.7 
                 8.6 
                 2200 
               
               
                 Example 5 
                 Example Compound 551 
                 5.6 
                 8.9 
                 2100 
               
               
                 Example 6 
                 Example Compound 873 
                 5.8 
                 8.7 
                 2300 
               
               
                 Example 7 
                 Example Compound 896 
                 5.7 
                 8.2 
                 2150 
               
               
                 Example 8 
                 Example Compound 855 
                 5.6 
                 8.8 
                 2000 
               
               
                 Comparative 
                 Comparative Example 
                 6.0 
                 6.2 
                 1700 
               
               
                 Example 1 
                 Compound R-1 
                   
                   
                   
               
               
                 Comparative 
                 Comparative Example 
                 6.0 
                 6.0 
                 1500 
               
               
                 Example 2 
                 Compound R-2 
                   
                   
                   
               
               
                 Comparative 
                 Comparative Example 
                 5.9 
                 7.4 
                 1800 
               
               
                 Example 3 
                 Compound R-3 
                   
                   
                   
               
               
                 Comparative 
                 Comparative Example 
                 6.1 
                 7.5 
                 1900 
               
               
                 Example 4 
                 Compound R-4 
                   
                   
                   
               
               
                 Comparative 
                 Comparative Example 
                 6.2 
                 5.8 
                 1950 
               
               
                 Example 5 
                 Compound R-5 
                   
                   
                   
               
               
                 Comparative 
                 Comparative Example 
                 6.3 
                 5.9 
                 1600 
               
               
                 Example 6 
                 Compound R-6 
               
               
                   
               
            
           
         
       
     
     Referring to Table 1 above, it may be identified that Examples 1 to 8 have achieved all of low voltage, long service life, and high efficiency compared to Comparative Examples 1 to 6. 
     A polycyclic compound according to an embodiment is used in the hole transport region to contribute to a low driving voltage, high efficiency, and long service life of organic electroluminescence devices. The polycyclic compound according to an embodiment is a non-amine compound having a linear benzoheterolephene-fused tetracyclic heteroacene skeleton with multiple heteroatoms. The polycyclic compound contains a structural bond of an indole and a benzohetero compound. In general, the indole side is relatively stable and the benzohetero compound side lacks the stability. The polycyclic compound according to an embodiment may become a more stable structure by adding a substituent increasing the stability to the unstable benzohetero compound. Accordingly, the polycyclic compound according to an embodiment may have excellent characteristics in heat resistance and charge resistance and achieve a long service life of the luminescence device. It is believed that N atoms, S atoms, or O atoms contained in the polycyclic compound of an embodiment may improve the hole transport ability of the entire molecule, and thus the recombination probability of holes and electrons in the emission layer is improved, thereby improving luminous efficiency of the luminescence device. 
     It can be seen that Example 5 achieved high device efficiency. In Example 5, it is believed that the introduction of an asymmetric meta-phenyl(4-dibenzothiophene) group to the benzoheterolephene-fused tetracyclic heteroacene ring breaks the symmetry of the entire molecule, thereby suppressing crystallinity and improving a hole transport property, and thus the recombination probability of holes and electrons in the emission layer is improved. 
     In Comparative Example 1 and Comparative Example 2, since the benzene ring adjacent to N is further condensed, the planarity is increased, and a sterically large volume structure cannot be taken. Therefore, both efficiency and service life of the luminescence device were reduced compared to Examples. 
     In Comparative Example 5 and Comparative Example 6, since the symmetry of the molecule is increased and crystallinity is thus good, the formation of film in the device may be suppressed. Thus, the efficiency and service life of the luminescence device were reduced. 
     The luminescence device according to an embodiment has excellent efficiency. 
     The polycyclic compound according to an embodiment may be used as a material of the hole transport region of the luminescence device, and thereby the luminescence device may have improved efficiency. 
     Embodiments have been disclosed herein, and although terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. In some instances, as would be apparent by one of ordinary skill in the art, features, characteristics, and/or elements described in connection with an embodiment may be used singly or in combination with features, characteristics, and/or elements described in connection with other embodiments unless otherwise specifically indicated. Accordingly, it will be understood by those of ordinary skill in the art that various changes in form and details may be made without departing from the spirit and scope of the disclosure as set forth in the following claims.