Organic electroluminescent devices

Abstract

An organic electroluminescent device is disclosed. The organic electroluminescent device of the embodiment includes a first electrode and a second electrode facing each other, and a plurality of organic layers disposed between the first electrode and the second electrode. At least one organic layer selected from the plurality of organic layers includes a fused polycyclic compound represented by Formula 1, thus the organic electroluminescent device can exhibit improved luminous efficiency. [Formula 1] Wherein, X1 to X3, Y1 to Y4, R1 to R6, R... 11 and R 12 n1 to n6 and m1 to m4 are the same as those defined in the instruction manual.

Description

[0001] This application claims priority and benefit to Korean Patent Application No. 10-2019-0098127, filed on August 12, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0002] One or more aspects of embodiments of this disclosure relate to an organic electroluminescent device and a fused polycyclic compound for the organic electroluminescent device, for example, to a fused polycyclic compound used as a luminescent material and an organic electroluminescent device comprising the fused polycyclic compound. Background Technology

[0003] Organic electroluminescent displays (OLEDs) are being actively developed as image displays. Unlike liquid crystal displays (LCDs), OLEDs are so-called self-emissive displays in which holes and electrons injected from the first and second electrodes recombine in the emitting layer, and light is emitted by a light-emitting material in the emitting layer that includes organic compounds, thereby achieving the display.

[0004] When applying organic light-emitting devices (OLEDs) to displays, it is desirable for OLEDs to have low driving voltage, high luminous efficiency, and long lifespan. Furthermore, it is desirable for the continuous development of materials for OLEDs that can stably meet these requirements.

[0005] Recently, technologies are being developed to realize high-efficiency organic electroluminescent displays by utilizing phosphorescence (from triplet energy levels) or delayed fluorescence emission (based on the phenomenon of generating singlet excitons by colliding triplet excitons (triplet-triplet annihilation, TTA)); and thermally activated delayed fluorescence (TADF) materials that can utilize delayed fluorescence emission phenomena are also being developed. Summary of the Invention

[0006] One or more aspects of embodiments of this disclosure relate to an organic electroluminescent device having improved luminous efficiency.

[0007] One or more aspects of embodiments of this disclosure relate to a fused polycyclic compound that can improve the luminous efficiency of an organic electroluminescent device.

[0008] One or more exemplary embodiments of this disclosure provide an organic electroluminescent device including a first electrode, a second electrode facing the first electrode, and a plurality of organic layers disposed between the first electrode and the second electrode. At least one organic layer selected from the plurality of organic layers comprises a fused polycyclic compound represented by Formula 1:

[0009] [Formula 1]

[0010]

[0011] In Formula 1, X1 to X3 can each be independently NR9, O, or S; Y1 to Y4 can each be independently a straight bond, O, or S; R1 to R6 can each be independently a hydrogen atom, a deuterium atom, a halogen atom, a boron group, a phosphonium oxide group, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted silyl group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 60 cyclic carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 60 cyclic carbon atoms, or a substituted or unsubstituted non-aromatic heterocyclic group having 2 to 60 cyclic carbon atoms, or can be combined with adjacent groups to form a ring, R 11 and R 12 Each of the following groups can be independently substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms, substituted or unsubstituted aryl groups having 6 to 60 cyclic carbon atoms, or substituted or unsubstituted heteroaryl groups having 2 to 60 cyclic carbon atoms, or can be combined with adjacent groups to form a ring. R9 can be substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms, substituted or unsubstituted aryl groups having 6 to 60 cyclic carbon atoms, or substituted or unsubstituted heteroaryl groups having 2 to 60 cyclic carbon atoms. n1 to n4 can each be independently integers from 0 to 2, n5 and n6 can each be independently integers from 0 to 3, and m1 to m4 can each be independently 0 or 1.

[0012] In an embodiment, the organic layer may include a hole transport region disposed on the first electrode, an emitter layer disposed on the hole transport region, and an electron transport region disposed on the emitter layer. The emitter layer may include a fused polycyclic compound represented by Formula 1.

[0013] The emission layer can emit delayed fluorescence.

[0014] The emission layer may be a delayed fluorescence emission layer comprising a host and a dopant. The dopant may include a fused polycyclic compound represented by Formula 1.

[0015] The emitter layer may include a host having a first lowest triplet excitation energy level, a first dopant having a second lowest triplet excitation energy level lower than the first lowest triplet excitation energy level, and a second dopant having a third lowest triplet excitation energy level lower than the second lowest triplet excitation energy level, wherein the first dopant may include a fused polycyclic compound represented by Formula 1.

[0016] The first dopant can be a delayed fluorescence dopant. The second dopant can be a fluorescent dopant.

[0017] In Equation 1, at least one of Y1 to Y4 is a direct-connect key. When Y1 is a direct-connect key, m1 can be 1. When Y2 is a direct-connect key, m2 can be 1. When Y3 is a direct-connect key, m3 can be 1. And when Y4 is a direct-connect key, m4 can be 1.

[0018] In the embodiments, the fused polycyclic compound represented by Formula 1 can be represented by Formula 1-1:

[0019] [Equation 1-1]

[0020]

[0021] In Formula 1-1, R7 and R8 can each independently be a hydrogen atom, a deuterium atom, a halogen atom, a boron group, a phosphonium oxide group, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted silyl group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 60 cyclic carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 60 cyclic carbon atoms, or can be combined with adjacent groups to form a ring, and n7 and n8 can each independently be an integer from 0 to 3. In Formula 1-1, X1 to X3, Y1 to Y4, R1 to R6, n1 to n6, and m1 to m4 can be the same as described in Formula 1.

[0022] The fused polycyclic compound represented by Formula 1-1 can be represented by Formula 2-1 or Formula 2-2:

[0023] [Equation 2-1]

[0024]

[0025] [Equation 2-2]

[0026]

[0027] In Equations 2-1 and 2-2, X1 to X3, Y1 to Y4, R1 to R8, n1 to n8, and m1 to m4 can be the same as those described in Equation 1-1.

[0028] The fused polycyclic compound represented by Formula 1-1 can be represented by Formula 3-1 or Formula 3-2:

[0029] [Equation 3-1]

[0030]

[0031] [Equation 3-2]

[0032]

[0033] In Equations 3-1 and 3-2, X1 to X3, R1 to R8, and n1 to n8 can be the same as those described in Equation 1-1.

[0034] The fused polycyclic compound represented by Equation 1-1 can be represented by Equation 4:

[0035] [Formula 4]

[0036]

[0037] In Equation 4, X1 to X3, Y1 to Y4, R1, R4, R5, R6, R7, R8 and m1 to m4 can be the same as those described in Equation 1-1.

[0038] In Equation 1, X2 and X3 can be the same, Y1 and Y3 can be the same, Y2 and Y4 can be the same, m1 and m3 can be the same, and m2 and m4 can be the same.

[0039] In Formula 1, when X1 to X3 are NR9, R9 can be a substituted or unsubstituted phenyl group.

[0040] In the embodiments, both the first electrode and the second electrode independently comprise at least one selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn, or two selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn. One or more compounds, a mixture of two or more selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn and Zn, or an oxide of one or more selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn and Zn.

[0041] The fused polycyclic compound according to an embodiment of the inventive concept can be represented by Formula 1.

[0042] In the fused polycyclic compound represented by Formula 1, the absolute value of the difference between the lowest singlet excitation level (S1) and the lowest triplet excitation level (T1) can be 0.33 eV or less. Attached Figure Description

[0043] The accompanying drawings are included to provide a further understanding of the inventive concept and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the inventive concept and, together with the description, serve to explain the principles of the inventive concept. In the drawings:

[0044] Figure 1 This is a schematic cross-sectional view of an organic electroluminescent device according to an embodiment of the present disclosure;

[0045] Figure 2 This is a schematic cross-sectional view of an organic electroluminescent device according to an embodiment of the present disclosure;

[0046] Figure 3 This is a schematic cross-sectional view of an organic electroluminescent device according to an embodiment of the present disclosure; and

[0047] Figure 4 This is a schematic cross-sectional view of an organic electroluminescent device according to an embodiment of the present disclosure. Detailed Implementation

[0048] This disclosure can have various modifications and can be implemented in different forms; therefore, specific embodiments will be illustrated in the accompanying drawings and described in the detailed description. However, it should be understood that this disclosure is not intended to limit it to any particular form, but rather, this disclosure covers all modifications, equivalents, and substitutions within the spirit and technical scope of this disclosure.

[0049] In the description, it will also be understood that when a component (region, layer, part, etc.) is referred to as being "on" another component, "connected to" or "combined to" another component, the component may be directly set / connected / combined to said other component, or (multiple) intermediate components may also be set therebetween.

[0050] The same reference numerals always denote the same elements, and redundant descriptions may be omitted. To effectively describe technical features, the thickness, dimensions, and proportions of components in the figures may be exaggerated.

[0051] "And / or" includes one or more combinations of related components that can be defined therein.

[0052] Although terms such as “first” and “second” are used herein to describe various components, these components should not be limited by these terms. These terms are used only to distinguish one component from another. For example, without departing from the scope of this disclosure, a first component may alternatively be referred to as a second component, and similarly, a second component may alternatively be referred to as a first component. Unless the context clearly indicates otherwise, singular expressions may include plural forms.

[0053] Furthermore, terms such as "below," "in the lower part," "above," and / or "in the upper part" may be used to describe the relationships between the components shown in the accompanying drawings. These terms are relative concepts and are described based on the directions shown in the accompanying drawings.

[0054] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It will also be understood that terms (such as those defined in a general dictionary) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formalized sense unless expressly stated or defined herein.

[0055] It will be understood that "including" or "having" means that the features, fixed figures, steps, processes, elements, components, or combinations thereof disclosed in the specification are present, but does not preclude the possibility of the presence or addition of one or more other features, fixed figures, steps, processes, elements, components, or combinations thereof.

[0056] In the following description, an organic electroluminescent device according to an embodiment of the present disclosure will be described with reference to the accompanying drawings.

[0057] Figures 1 to 4 These are schematic cross-sectional views of an organic electroluminescent device according to embodiments of the present disclosure. (Refer to...) Figures 1 to 4 In the organic electroluminescent device 10 according to an embodiment of the present disclosure, a first electrode EL1 and a second electrode EL2 are positioned facing each other, and a plurality of organic layers may be disposed between the first electrode EL1 and the second electrode EL2. The plurality of organic layers may include a hole transport region (HTR), an emitter layer (EML), and an electron transport region (ETR). That is, the organic electroluminescent device 10 according to an embodiment of the present disclosure may include a first electrode EL1, a hole transport region (HTR), an emitter layer (EML), an electron transport region (ETR), and a second electrode EL2 sequentially stacked. A capping layer (CPL) may be disposed on the second electrode EL2.

[0058] The organic electroluminescent device 10 of the embodiments may include, in at least one of a plurality of organic layers disposed between the first electrode EL1 and the second electrode EL2, a fused polycyclic compound (as described below) according to embodiments of the present disclosure. For example, the organic electroluminescent device 10 of the embodiments may include, in the emitter layer EML disposed between the first electrode EL1 and the second electrode EL2, a fused polycyclic compound according to embodiments as described below. However, the embodiments are not limited thereto, and the organic electroluminescent device 10 of the embodiments may include, in at least one organic layer comprising the hole transport region HTR and the electron transport region ETR among the plurality of organic layers disposed between the first electrode EL1 and the second electrode EL2, a fused polycyclic compound according to embodiments of the present disclosure may be included in the capping layer CPL disposed on the second electrode EL2.

[0059] and Figure 1 compared to, Figure 2 A cross-sectional view of an organic electroluminescent device 10 according to an embodiment is shown, wherein the hole transport region HTR includes a hole injection layer HIL and a hole transport layer HTL, and the electron transport region ETR includes an electron injection layer EIL and an electron transport layer ETL. Figure 1 compared to, Figure 3 A cross-sectional view of an organic electroluminescent device 10 according to an embodiment is shown, wherein the hole transport region HTR includes a hole injection layer HIL, a hole transport layer HTL, and an electron blocking layer EBL, and the electron transport region ETR includes an electron injection layer EIL, an electron transport layer ETL, and a hole blocking layer HBL. Figure 2 compared to, Figure 4 A cross-sectional view of an organic electroluminescent device 10 according to an embodiment is shown. The organic electroluminescent device 10 includes a capping layer CPL disposed on a second electrode EL2.

[0060] In the following description of the organic electroluminescent device 10 of the embodiments, the organic electroluminescent device 10 includes a fused polycyclic compound according to the embodiments of the present disclosure in the emitter layer EML, but the embodiments are not limited thereto. The fused polycyclic compound according to the embodiments described below may be included in the hole transport region HTR, the electron transport region ETR, or the capping layer CPL.

[0061] The first electrode EL1 is conductive (e.g., it may be conductive). The first electrode EL1 may be formed of a metal alloy or a conductive compound. The first electrode EL1 may be an anode. Alternatively, the first electrode EL1 may be a pixel electrode. The first electrode EL1 may be a transmissive electrode, a transflective (semi-transmissive) electrode, or a reflective electrode. When the first electrode EL1 is a transmissive electrode, the first electrode EL1 may include a transparent metal oxide (e.g., indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), or indium tin zinc oxide (ITZO)) or be formed of a transparent metal oxide (e.g., indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), or indium tin zinc oxide (ITZO)). When the first electrode EL1 is a transmissive or reflective electrode, the first electrode EL1 may include silver (Ag), magnesium (Mg), copper (Cu), aluminum (Al), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), LiF / Ca, LiF / Al, molybdenum (Mo), titanium (Ti), or their compounds or mixtures (e.g., a mixture of Ag and Mg) or oxides, or may be formed from silver (Ag), magnesium (Mg), copper (Cu), aluminum (Al), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), LiF / Ca, LiF / Al, molybdenum (Mo), titanium (Ti), or their compounds or mixtures (e.g., a mixture of Ag and Mg) or oxides. In some embodiments, the first electrode EL1 may have a multilayer structure, including a reflective layer or a transflective layer and a transparent conductive layer formed of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), and / or indium tin zinc oxide (ITZO). For example, the first electrode EL1 may have, but is not limited to, a three-layer structure of ITO / Ag / ITO. The first electrode EL1 may have approximately to approximately (For example, about to approximately The thickness of ).

[0062] A hole transport region (HTR) is disposed on the first electrode EL1. The hole transport region (HTR) may include at least one selected from a hole injection layer (HIL), a hole transport layer (HTL), a hole buffer layer, and an electron blocking layer (EBL). The hole transport region (HTR) may have, for example, approximately... to approximately The thickness.

[0063] The hole transport region (HTR) can have a multilayer structure, which may consist of a single layer made of a single material, a single layer made of two or more different materials, or multiple layers made of various different materials.

[0064] For example, the hole transport region HTR can have a single-layer structure including a hole injection layer HIL or a hole transport layer HTL, or a single-layer structure formed of a hole injection material or a hole transport material. In some embodiments, the hole transport region HTR can have a single-layer structure formed of materials different from each other, or it can have a multilayer structure including a hole injection layer HIL / hole transport layer HTL, a hole injection layer HIL / hole transport layer HTL / hole buffer layer, a hole injection layer HIL / hole buffer layer, a hole transport layer HTL / hole buffer layer, or a hole injection layer HIL / hole transport layer HTL / electron blocking layer EBL, wherein the layers in each structure are sequentially stacked from the first electrode EL1, but the embodiments are not limited thereto.

[0065] Hole transport regions (HTRs) can be formed using a variety of suitable methods, such as vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) methods, inkjet printing, laser printing, and / or laser-induced thermal imaging (LITI) methods.

[0066] Hole injection layer HIL can include, for example, phthalocyanine compounds (such as copper phthalocyanine), N,N'-diphenyl-N,N'-bis[4-(di-m-tolyl-amino)-phenyl]-biphenyl-4,4'-diamine (DNTPD), 4,4',4”-[tris(3-methylphenyl)phenylamino]triphenylamine (m-MTDATA), 4,4',4”-tris(N,N-diphenylamino)triphenylamine (TDATA), 4,4',4”-tri{N-(2-naphthyl)-N-phenylamino}-triphenylamine (2-TNATA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) Poly(4-styrene sulfonate) (PEDOT / PSS), polyaniline / dodecylbenzenesulfonic acid (PANI / DBSA), polyaniline / camphor sulfonic acid (PANI / CSA), polyaniline / poly(4-styrene sulfonate) (PANI / PSS), N,N'-di(naphthyl-1-yl)-N,N'-diphenyl-benzidine (NPB), triphenylamine-containing polyether ketone (TPAPEK), 4-isopropyl-4'-methyldiphenyliodonium tetra(pentafluorophenyl)boronic acid, dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexaonitrile (HAT-CN), etc.

[0067] Hole transport layers (HTLs) may further include, for example, carbazole derivatives (such as N-phenylcarbazole and polyvinylcarbazole), 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'-bis(naphthyl-1-yl)-N,N'-diphenyl-benzidine (NPB), 4,4'-cyclohexylenebis[N,N-bis(4-methylphenyl)aniline] (TAPC), 4,4'-bis[N,N'-(3-tolyl)amino]-3,3'-dimethylbiphenyl (HMTPD), 1,3-bis(N-carbazolyl)benzene (mCP), etc.

[0068] The hole transport region (HTR) can have approximately to approximately (For example, about to approximately The hole injection layer (HIL) can have a thickness of, for example, approximately... to approximately The thickness, and the hole transport layer HTL can have approximately to approximately The thickness. For example, the electron blocking layer (EBL) can have approximately [a certain thickness]. to approximately The thickness of the hole transport region (HTR), hole injection layer (HIL), hole transport layer (HTL), and electron blocking layer (EBL) must meet the above-mentioned range to achieve satisfactory hole transport characteristics without significantly increasing the driving voltage.

[0069] In addition to the materials described above, the hole transport region (HTR) may also include a charge-generating material to improve conductivity. The charge-generating material may be uniformly or non-uniformly dispersed in the hole transport region (HTR). The charge-generating material may be, for example, a p-doper. The p-doper may be, but is not limited to, quinone derivatives, metal oxides, and cyano-containing compounds. Non-limiting examples of p-dopers may include quinone derivatives (such as tetracyanoquinone dimethyl (TCNQ) and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinone dimethyl (F4-TCNQ)) and metal oxides (such as tungsten oxide and molybdenum oxide).

[0070] As described above, in addition to the hole injection layer (HIL) and the hole transport layer (HTL), the hole transport region (HTR) may also include at least one of a hole buffer layer and an electron blocking layer (EBL). The hole buffer layer can compensate for the resonant distance to improve luminous efficiency based on the wavelength of light emitted from the emitter layer (EML). The material included in the hole transport layer (HTL) can also be used as the material in the hole buffer layer. The electron blocking layer (EBL) can block or reduce the injection of electrons from the electron transport region (ETR) into the hole transport region (HTR).

[0071] The emitter layer EML is disposed on the hole transmission region HTR. The emitter layer EML can have, for example, approximately to approximately or about to approximately The thickness of the emitter layer (EML) can be a single-layer structure formed of a single material, a single layer formed of different materials (e.g., formed of multiple materials), or a multi-layer structure comprising multiple layers formed of different materials.

[0072] The emission layer EML in the organic electroluminescent device 10 of the embodiment may include the fused polycyclic compound of the embodiment.

[0073] In the specification, the term "substituted or unsubstituted" can refer to something that is unsubstituted or substituted with at least one substituent selected from the group consisting of deuterium, halogen, cyano, nitro, amino (or amino), silyl, oxygen (or "oxy-containing"), thio, sulfinyl, sulfonyl, carbonyl, boron, phosphonyl oxide, phosphonyl sulfide, alkyl, alkenyl, alkoxy, cycloalkyl, aryl, and heterocyclic groups. Furthermore, each substituent itself can be substituted or unsubstituted. For example, biphenyl can be interpreted as an unsubstituted aryl group or a phenyl group substituted with a phenyl group.

[0074] In the specification, the phrase "bonding to adjacent groups to form a ring" refers to the state of bonding with adjacent groups to form a substituted or unsubstituted hydrocarbon ring or a substituted or unsubstituted heterocyclic ring. The hydrocarbon ring can be an aliphatic hydrocarbon ring or an aromatic hydrocarbon ring. The heterocyclic ring can be an aliphatic heterocyclic ring or an aromatic heterocyclic ring. The ring formed by bonding adjacent groups to each other can be a monocyclic ring or a polycyclic ring. Furthermore, the ring formed by bonding to adjacent groups can be attached to another ring to form a spirostructure.

[0075] In the specification, the term "adjacent group" can refer to a substituent on a directly adjacent atom, a substituent on the same atom, or a substituent spatially adjacent to that substituent (e.g., a group not on the same atom or adjacent atoms but within the bonding distance when considering the three-dimensional conformation of the molecule). For example, the two methyl groups in 1,2-dimethylbenzene can be interpreted as "adjacent groups" to each other, and the two ethyl groups in 1,1-diethylcyclopentane can be interpreted as "adjacent groups" to each other.

[0076] In the specification, the term "halogen atom" may refer to a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom.

[0077] In the specification, the term "alkyl" may refer to a straight-chain alkyl, a branched alkyl, or a cyclic alkyl. The number of carbon atoms in an alkyl group may be 1 to 50, 1 to 30, 1 to 20, 1 to 10, or 1 to 6. Non-limiting examples of alkyl groups may include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, isobutyl, 2-ethylbutyl, 3,3-dimethylbutyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, cyclopentyl, 1-methylpentyl, 3-methylpentyl, 2-ethylpentyl, 4-methyl-2-pentyl, n-hexyl, 1-methylhexyl, 2-ethylhexyl, 2-butylhexyl, cyclohexyl, 4-methylcyclohexyl, 4-tert-butylcyclohexyl, n-heptyl, 1-methylheptyl, 2,2-dimethylheptyl, 2-ethylheptyl, 2-butylheptyl, n-octyl, tert-octyl, 2-ethyloctyl, 2-butyloctyl, 2-hexyloctyl, 3,7-dimethyloctyl, cyclooctyl, n-nonyl, n-decyl, adamantyl, 2-ethyldecyl, 2- Butyldecyl, 2-hexyldecyl, 2-octyldecyl, undecyl, dodecyl, 2-ethyldodecyl, 2-butyldodecyl, 2-hexyldodecyl, 2-octyldodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, 2-ethylhexadecyl, 2-butylhexadecyl, 2-hexylhexadecyl, 2-octylhexadecyl, heptadecanyl, octadecyl, nonadecanyl, eicosyl, 2-ethyleicosyl, 2-butyleicosyl, 2-hexyleicosyl, 2-octyleicosyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecanyl, hexadecyl, hexadecyl, nonadecanyl, triadecyl, etc.

[0078] In this specification, the term "alkenyl" refers to a hydrocarbon group comprising at least one carbon-carbon double bond at the middle or end of an alkyl group having two or more carbon atoms. Alkenyl groups can be straight-chain or branched. The number of carbon atoms can be 2 to 60, 2 to 30, 2 to 20, or 2 to 10, but is not limited thereto. Non-limiting examples of alkenyl groups include vinyl (vinyl group), propenyl, 1-butenyl, 1-pentenyl, hexenyl, heptenyl, octenyl, 1,3-butadienyl, styryl, styrylvinyl, etc.

[0079] In this specification, the term "alkynyl" refers to a hydrocarbon group comprising at least one carbon-carbon triple bond at the middle or end of an alkyl group having two or more carbon atoms. The alkynyl group can be straight-chain or branched. The number of carbon atoms can be 2 to 60, 2 to 30, 2 to 20, or 2 to 10, but is not limited thereto. Non-limiting examples of alkynyl groups include ethynyl, propynyl, etc.

[0080] In this specification, the term "hydrocyclotrimonium" refers to any functional group or substituent derived from an aliphatic hydrocarbon ring or any functional group or substituent derived from an aromatic hydrocarbon ring. The ring used to form the hydrocyclotrimonium may have 5 to 60, 5 to 30, or 5 to 20 carbon atoms.

[0081] In this specification, the term "aryl" refers to any functional group or substituent derived from an aromatic hydrocarbon ring. Aryl groups can be monocyclic or polycyclic. The ring used to form the aryl group can have 6 to 60, 6 to 30, 6 to 20, or 6 to 15 carbon atoms. Non-limiting examples of aryl groups include phenyl, naphthyl, fluorenyl, anthracene, phenanthryl, biphenyl, terphenyl, tetraphenyl, pentaphenyl, hexaphenyl, benzo[9,10]phenanthryl, pyrene, benzofluoranthracene, etc. Base, etc.

[0082] In the specification, the fluorene group can be substituted, and two substituents can combine with each other to form a spirostructure. Non-limiting examples of substituted fluorene groups are given below. However, embodiments of this disclosure are not limited thereto:

[0083]

[0084] In this specification, the term "heterocyclic group" refers to any functional group or substituent derived from a ring comprising one or more heteroatoms selected from boron (B), oxygen (O), nitrogen (N), phosphorus (P), silicon (Si), and sulfur (S). Heterocyclic groups include aliphatic heterocyclic groups and aromatic heterocyclic groups. Aromatic heterocyclic groups can be heteroaryl. Aliphatic and aromatic heterocyclic groups can be monocyclic or polycyclic.

[0085] In the specification, the heterocyclic group may include one or more heteroatoms selected from B, O, N, P, Si, and S. When the heterocyclic group includes two or more heteroatoms, the two or more heteroatoms may be the same or different from each other. The heterocyclic group may be a monocyclic or polycyclic heterocyclic group and may include a heteroaryl group. The ring used to form the heterocyclic group may have 2 to 30, 2 to 20, or 2 to 10 carbon atoms.

[0086] In this specification, the term "aliphatic heterocyclic group" may refer to a non-aromatic heterocyclic group comprising one or more heteroatoms selected from B, O, N, P, Si, and S. The ring used to form the aliphatic heterocyclic group may have 2 to 60, 2 to 30, 2 to 20, or 2 to 10 carbon atoms. Non-limiting examples of aliphatic heterocyclic groups include ethylene oxide, thiopropylcycloalkyl, pyrrolyl, piperidinyl, tetrahydrofuranyl, tetrahydrothiophenyl, thiaalkyl (thiocyclopentyl group), tetrahydropyranyl, 1,4-dioxane, tetrahydroquinolinyl, etc.

[0087] In this specification, the term "heteroaryl" may refer to an aromatic heterocyclic group comprising one or more heteroatoms selected from B, O, N, P, Si, and S. Where a heteroaryl comprises two or more heteroatoms, the two or more heteroatoms may be the same or different from each other. A heteroaryl may be a monocyclic or polycyclic heterocyclic group. The ring used to form the heteroaryl may have 2 to 60, 2 to 30, 2 to 20, or 2 to 10 carbon atoms. Non-limiting examples of heteroaryl groups include thienyl, furanyl, pyrrolyl, imidazolyl, triazolyl, pyridyl, bipyridyl, pyrimidinyl, triazinyl, acridineyl, pyridazinyl, quinolinyl, quinazolinyl, quinoxazinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, pyrazinopyrazinyl, isoquinolinyl, indolyl, carbazoleyl, N-arylcarbazoleyl, N-heteroarylcarbazoleyl, N-alkylcarbazoleyl, benzoxazolyl, benzimidazolyl, benzothiazolyl, benzocarbazoleyl, benzothiaphenyl, dibenzothiaphenyl, thienothiaphenyl, benzofuranyl, phenanthrololinyl, thiazolyl, isoxazolyl, oxazolyl, oxadiazolyl, thiadiazolyl, phenthiazolyl, dibenzothiazolyl, dibenzofuranyl, etc.

[0088] In this disclosure, the term "arylene" may refer to a description substantially the same as that given to aryl groups, except that the arylene group is a divalent group. The term "heteroarylene" may refer to a description substantially the same as that given to heteroaryl groups, except that the heteroarylene group is a divalent group.

[0089] In this specification, the term "silyl" may refer to alkylsilyl or arylsilyl. Non-limiting examples of silyl include trimethylsilyl, triethylsilyl, tert-butyldimethylsilyl, vinyldimethylsilyl, propyldimethylsilyl, triphenylsilyl, diphenylsilyl, phenylsilyl, etc.

[0090] In this specification, the term "boron-based" may refer to alkylboron-based or arylboron-based. Non-limiting examples of boron-based compounds include trimethylboron-based, triethylboron-based, tert-butyldimethylboron-based, triphenylboron-based, diphenylboron-based, phenylboron-based, etc.

[0091] In the specification, the number of carbon atoms in the amino group can be from 1 to 30, but is not particularly limited thereto. The amino group can include alkylamino, arylamino, or heteroarylamino. Non-limiting examples of amino groups include methylamino, dimethylamino, phenylamino, diphenylamino, naphthylamino, 9-methyl-anthraylamino, etc.

[0092] In this specification, the term "oxygen group" may refer to an alkyloxy group or an aryloxy group. An alkyloxy group may include a straight-chain, branched, or cyclic chain. The number of carbon atoms in an alkyloxy group may be, for example, 1 to 20 or 1 to 10, but is not particularly limited thereto. Non-limiting examples of oxy groups include methoxy, ethoxy, n-propoxy, isopropoxy, butoxy, pentoxy, hexoxy, octoxy, nonoxy, decoxy, benzyloxy, etc.

[0093] In the specification, the alkyl group in alkylthio, alkylsulfonyl, alkylaryl, alkylamino, alkylboryl and alkylsilyl is the same as the alkyl group described above (including examples thereof).

[0094] In the specification, the aryl groups in aryloxy, arylthio, arylsulfonyl, arylamino, arylboryl, and arylsilyl are the same as the aryl groups described above (including examples thereof).

[0095] In the instruction manual, the term "direct-connect key" can refer to a single key.

[0096] The fused polycyclic compounds of the embodiments can be represented by Formula 1: The fused polycyclic compounds represented by Formula 1 can have at least one fused polycyclic heterocyclic moiety (such as a carbazole moiety, a dibenzofuran moiety, or a dibenzothiophene moiety) in the fused ring.

[0097] [Formula 1]

[0098]

[0099] In Equation 1, X1 to X3 can each be independently NR9, 0, or S. For example, X1 can be NR9 and both X2 and X3 can be 0, or all of X1 to X3 can be S. In some embodiments, all of X1 to X3 can be NR9. In some embodiments, X1 can be 0 or S, and both X2 and X3 can be NR9. In some embodiments, all of X1 to X3 can each be independently 0 or S.

[0100] In Equation 1, Y1 to Y4 can each be a direct bond, O, or S independently.

[0101] In Equation 1, m1 to m4 can each be independently 0 or 1. In Equation 1, when X1 is 0 or S, m1 + m2 + m3 + m4 can be non-zero. In other words, when X1 is 0 or S, at least one selected from m1 to m4 can be non-zero (e.g., it can be 1). When X1 is 0 or S, m1 + m2 + m3 + m4 can be 2.

[0102] In Equation 1, at least one of Y1 to Y4 can be a direct-connect key. When Y1 is a direct-connect key, m1 can be 1. When Y2 is a direct-connect key, m2 can be 1. When Y3 is a direct-connect key, m3 can be 1. When Y4 is a direct-connect key, m4 can be 1.

[0103] In Formula 1, R1 to R6 can each independently be a hydrogen atom, a deuterium atom, a halogen atom, a boron group, a phosphonium oxide group, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted silyl group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 60 cyclic carbon atoms, a substituted or unsubstituted heteroaryl group having 2 to 60 cyclic carbon atoms, or a substituted or unsubstituted non-aromatic heterocyclic group having 2 to 60 cyclic carbon atoms. In some embodiments, each of R1 to R6 can be combined with an adjacent group to form a ring. In some embodiments, all of R1 to R6 can be hydrogen atoms. In some embodiments, R1, R4, R5, and R6 can each independently be a substituted or unsubstituted amino group, a substituted or unsubstituted methyl group, or a substituted or unsubstituted carbazole group. In some embodiments, R1, R4, R5, and R6 may each be independently substituted or unsubstituted tert-butyl, substituted or unsubstituted carbazole, substituted or unsubstituted diphenylamine, substituted or unsubstituted isopropylaniline, substituted or unsubstituted piperidinyl, or substituted or unsubstituted tetrahydroquinoline.

[0104] In Formula 1, R9 can be a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 60 cyclic carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 60 cyclic carbon atoms. In Formula 1, when X1 to X3 are all NR9, each R9 can independently be a substituted or unsubstituted phenyl group. In Formula 1, R 11 and R 12 They can all be independently substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms, substituted or unsubstituted aryl groups having 6 to 60 cyclic carbon atoms, or substituted or unsubstituted heteroaryl groups having 2 to 60 cyclic carbon atoms, or they can be combined with adjacent groups to form a ring.

[0105] In Formula 1, n1 to n4 can each be an independent integer from 0 to 2, and n5 and n6 can each be an independent integer from 0 to 3. When n1 is 0, the fused polycyclic compound according to the embodiment may not be substituted by R1. The case where n1 is 2 and all R1 groups are hydrogen atoms can be substantially the same as the case where n1 is 0. When n1 is 2, all of the plurality of R1 groups may be the same, or at least one of the plurality of R1 groups may be different from the others. When n2 is 0, the fused polycyclic compound according to the embodiment may not be substituted by R2. The case where n2 is 2 and all R2 groups are hydrogen atoms can be substantially the same as the case where n2 is 0. When n2 is 2, all of the plurality of R2 groups may be the same, or at least one of the plurality of R2 groups may be different from the others. When n3 is 0, the fused polycyclic compound according to the embodiment may not be substituted by R3. The case where n3 is 2 and all R3 groups are hydrogen atoms can be substantially the same as the case where n3 is 0. When n3 is 2, all R3 groups may be identical, or at least one of the R3 groups may be different from the others. When n4 is 0, the fused polycyclic compound according to the embodiments may not be substituted by R4. The case where n4 is 2 and all R4 groups are hydrogen atoms is substantially the same as the case where n4 is 0. When n4 is 2, all R4 groups may be identical, or at least one of the R4 groups may be different from the others. When n5 is 0, the fused polycyclic compound according to the embodiments may not be substituted by R5. The case where n5 is 3 and all R5 groups are hydrogen atoms is substantially the same as the case where n5 is 0. When n5 is 2 or a larger integer, all R5 groups may be identical, or at least one of the R5 groups may be different from the others. When n6 is 0, the fused polycyclic compound according to the embodiments may not be substituted by R6. The case where n6 is 3 and all R6 groups are hydrogen atoms is substantially the same as the case where n6 is 0. When n6 is 2 or a larger integer, all R6 groups may be identical, or at least one of the R6 groups may be different from the others.

[0106] The fused polycyclic compounds of the embodiments may have a symmetrical structure (e.g., they may have mirror symmetry). For example, the fused polycyclic compound of Formula 1 of the embodiments may have a symmetrical structure around a central ring including X1. In Formula 1, X2 and X3 may be the same, Y1 and Y3 may be the same, Y2 and Y4 may be the same, m1 and m3 may be the same, and m2 and m4 may be the same.

[0107] Compared to polycyclic rings in related technologies that contain nitrogen and boron atoms in the core, the fused polycyclic compounds of the embodiments comprise two polycyclic rings containing nitrogen and boron atoms, and have a structure in which the two polycyclic rings are connected to each other via fused heterocyclic rings (such as carbazole, dibenzofuran, or dibenzothiophene). For example, the fused polycyclic compounds of the embodiments may have fused polycyclic heterocyclic moieties (such as carbazole, dibenzofuran, or dibenzothiophene) in the polycyclic rings containing nitrogen and boron atoms, or have a structure in which the two polycyclic rings are connected to each other via fused heterocyclic moieties (such as carbazole, dibenzofuran, or dibenzothiophene). Therefore, the fused polycyclic compounds of the embodiments can be used as delayed fluorescence emission materials because they readily allow for HOMO and LUMO separation within a single molecule (facilitated by the presence of multiple resonance structures in a broad planar framework containing one or more fused polycyclic heterocyclic moieties (such as carbazole moieties, dibenzofuran moieties, or dibenzothiophene moieties). The fused polycyclic compounds of the embodiments can have a relatively reduced energy difference (ΔE) between the lowest triplet excitation level (T1 level) and the lowest singlet excitation level (S1 level) associated with the above structure. ST Therefore, when fused polycyclic compounds are used as delayed fluorescence emission materials, the luminous efficiency of organic electroluminescent devices can be improved.

[0108] The fused polycyclic compound represented by Formula 1 can be represented by Formula 1-1:

[0109] [Equation 1-1]

[0110]

[0111] In Formula 1-1, R7 and R8 may each independently be a hydrogen atom, a deuterium atom, a halogen atom, a boron group, a phosphonium oxide group, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted silyl group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 60 cyclic carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 60 cyclic carbon atoms. In some embodiments, each of R7 and R8 may be combined with an adjacent group to form a ring. For example, both R7 and R8 may be hydrogen atoms. In some embodiments, R7 and R8 may each independently be a substituted or unsubstituted amino group, a substituted or unsubstituted methyl group, or a substituted or unsubstituted carbazole group. In some embodiments, R7 and R8 may each independently be a substituted or unsubstituted tert-butyl group, a substituted or unsubstituted carbazole group, a substituted or unsubstituted diphenylamino group, a substituted or unsubstituted isopropylaniline group, or a substituted or unsubstituted piperidinyl group.

[0112] In Formula 1, n7 and n8 can both be independent integers from 0 to 3. When n7 is 0, the fused polycyclic compound according to the embodiments may not be substituted by R7. The case where n7 is 3 and all R7 groups are hydrogen atoms can be substantially the same as the case where n7 is 0. When n7 is 2 or a larger integer, all of the plurality of R7 groups may be identical, or at least one of the plurality of R7 groups may be different from the others. When n8 is 0, the fused polycyclic compound according to the embodiments may not be substituted by R8. The case where n8 is 3 and all R8 groups are hydrogen atoms can be substantially the same as the case where n8 is 0. When n8 is 2 or a larger integer, all of the plurality of R8 groups may be identical, or at least one of the plurality of R8 groups may be different from the others.

[0113] In Equation 1-1, X1 to X3, Y1 to Y4, R1 to R6, n1 to n6, and m1 to m4 can all be substantially the same as those described in Equation 1.

[0114] The fused polycyclic compound represented by Formula 1-1 can be represented by Formula 2-1 or Formula 2-2:

[0115] [Equation 2-1]

[0116]

[0117] [Equation 2-2]

[0118]

[0119] Equation 2-1 can be the case where m2 and m4 are both 1 and Y2 and Y4 are both direct-connected keys in Equation 1-1. Equation 2-2 can be the case where m1 and m3 are both 1 and Y1 and Y3 are both direct-connected keys in Equation 1-1.

[0120] In Equations 2-1 and 2-2, X1 to X3, Y1 to Y4, R1 to R8, n1 to n8, and m1 to m4 can all be substantially the same as those described in Equation 1-1.

[0121] The fused polycyclic compound represented by Formula 1-1 can be represented by Formula 3-1 or Formula 3-2:

[0122] [Equation 3-1]

[0123]

[0124] [Equation 3-2]

[0125]

[0126] Equation 3-1 can be the case where m2 and m4 are both 1, Y2 and Y4 are both direct-connected keys, and m1 and m3 are both 0. Equation 3-2 can be the case where m1 and m3 are both 1, Y1 and Y3 are both direct-connected keys, and m2 and m4 are both 0.

[0127] In Equations 3-1 and 3-2, X1 to X3, R1 to R8, and n1 to n8 can all be substantially the same as those described in Equation 1-1.

[0128] The fused polycyclic compound represented by Equation 1-1 can be represented by Equation 4:

[0129] [Formula 4]

[0130]

[0131] Equation 4 can be the case where n1, n4, n5, n6, n7 and n8 in Equation 1-1 are all 1, and the substitution bits of R1, R4, R5, R6, R7 and R8 are all specified.

[0132] The fused polycyclic compound represented by Formula 4 can have a symmetrical structure. The fused polycyclic compound represented by Formula 4 in the examples can have a symmetrical structure surrounding a central ring including X1. In Formula 4, X2 and X3 can be identical, Y1 and Y3 can be identical, Y2 and Y4 can be identical, m1 and m3 can be identical, and m2 and m4 can be identical. In Formula 4, R1 and R4 can be identical, R5 and R6 can be identical, and R8 and R7 can be identical.

[0133] In Equation 4, X1 to X3, Y1 to Y4, R1, R4, R5, R6, R7 and R8, and m1 to m4 can all be the same as those described in Equation 1-1.

[0134] The fused polycyclic compound in the embodiments can be any compound selected from the compounds represented by compound group 1. The organic electroluminescent device 10 in the embodiments may include at least one fused polycyclic compound selected from the compounds represented by compound group 1 and compound group 2 in the emitting layer EML:

[0135] [Compound Group 1]

[0136]

[0137]

[0138]

[0139]

[0140]

[0141] [Compound Group 2]

[0142]

[0143]

[0144]

[0145] The fused polycyclic compound represented by Formula 1 in the embodiments can be a thermally activated delayed fluorescence emission material. Furthermore, the fused polycyclic compound represented by Formula 1 in the embodiments can be a material having an energy difference (ΔE) between the lowest triplet excitation level (T1 level) and the lowest singlet excitation level (S1 level) of 0.33 eV or less. ST The thermally activated delayed fluorescence dopant is used. The fused polycyclic compound represented by Formula 1 in the examples can be an energy difference (ΔE) between the lowest triplet excitation level (T1 level) and the lowest singlet excitation level (S1 level) of 0.2 eV or less. ST The thermally activated delayed fluorescence dopant is used. The fused polycyclic compound represented by Formula 1 in the examples can be an energy difference (ΔE) between the lowest triplet excitation level (T1 level) and the lowest singlet excitation level (S1 level) of 0.1 eV or less. ST Thermally activated delayed fluorescence dopant.

[0146] The fused polycyclic compound represented by Formula 1 in the embodiments can be a luminescent material having a central emission wavelength in the wavelength region of 430 nm to 490 nm. For example, the fused polycyclic compound represented by Formula 1 in the embodiments can be a blue thermally activated delayed fluorescence (TADF) dopant. However, the embodiments are not limited thereto. When the fused polycyclic compound of the embodiments is used as a luminescent material, the fused polycyclic compound can be used as a dopant material to emit light in any suitable wavelength region, and the fused polycyclic compound can be used as a red luminescent dopant and a green luminescent dopant.

[0147] The emitting layer EML in the organic electroluminescent device 10 of the embodiment can emit delayed fluorescence. For example, the emitting layer EML can emit thermally activated delayed fluorescence (TADF).

[0148] In some embodiments, the emitting layer EML of the organic electroluminescent device 10 can emit blue light. For example, the emitting layer EML of the organic electroluminescent device 10 in the embodiments can emit blue light in the wavelength region of 490 nm or larger. However, the embodiments are not limited to this, and in some embodiments, the emitting layer EML can emit green or red light.

[0149] The organic electroluminescent device 10 of the embodiment may include multiple emission layers. The multiple emission layers may be sequentially stacked and arranged; for example, the organic electroluminescent device 10 including multiple emission layers may emit white light. The organic electroluminescent device 10 including multiple emission layers may be an organic electroluminescent device with a series structure. When the organic electroluminescent device 10 includes multiple emission layers, at least one emission layer EML may include a fused polycyclic compound as described above in the embodiments.

[0150] In embodiments, the emitter layer EML includes a host and a dopant, and may include the aforementioned fused polycyclic compounds as dopant. For example, the emitter layer EML in the organic electroluminescent device 10 of the embodiment may include a host for emitting delayed fluorescence and a dopant for emitting delayed fluorescence, and may include the aforementioned fused polycyclic compounds as dopant for emitting delayed fluorescence. The emitter layer EML may include at least one selected from the fused polycyclic compounds represented by compound group 1 as a thermally activated delayed fluorescence dopant.

[0151] In this embodiment, the emission layer EML is a delayed fluorescence emission layer, and the emission layer EML may comprise any suitable host material and the fused polycyclic compound described above. For example, in this embodiment, the fused polycyclic compound may be used as a TADF dopant.

[0152] In this embodiment, the emitter layer EML may include any suitable host material. Any suitable material can be used as the host material of the emitter layer EML, for example, selected from fluoranthene derivatives, pyrene derivatives, arylaceyne derivatives, anthracene derivatives, fluorene derivatives, perylene derivatives, etc. One of the derivatives, etc. In some embodiments, the host material may include pyrene derivatives, perylene derivatives, and anthracene derivatives. For example, as the host material of the emission layer EML, an anthracene derivative represented by Formula 5 can be used:

[0153] [Formula 5]

[0154]

[0155] In Formula 5, W1 to W4 can each be independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted silyl group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 cyclic carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 cyclic carbon atoms, or can be combined with adjacent groups to form a ring, wherein m1 and m2 can each be independently an integer from 0 to 4, and m3 and m4 can each be independently an integer from 0 to 5.

[0156] When m1 is 1, W1 can be a non-hydrogen atom; when m2 is 1, W2 can be a non-hydrogen atom; when m3 is 1, W3 can be a non-hydrogen atom; when m4 is 1, W4 can be a non-hydrogen atom.

[0157] When m1 is 2 or greater, multiple W1 groups may be the same or different. When m2 is 2 or greater, multiple W2 groups may be the same or different. When m3 is 2 or greater, multiple W3 groups may be the same or different. When m4 is 2 or greater, multiple W4 groups may be the same or different.

[0158] The compounds represented by Formula 5 can be represented by the following structures, but the compounds represented by Formula 5 are not limited to these:

[0159]

[0160] In embodiments, the emitter layer EML may include tris(8-hydroxyquinoline)aluminum (Alq3), 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CBP), poly(n-vinylcarbazole) (PVK), 9,10-bis(naphthyl-2-yl)anthracene (ADN), 4,4',4”-tris(carbazolyl-9-yl)-triphenylamine (TCTA), 1,3,5-tris(N-phenylbenzimidazolyl-2-yl)benzene (TPBi), 2-tert-butyl-9,10-bis(naphthyl-2-yl)anthracene (TBADN), distyrylarylene (DSA), 4,4'-bis(9-carbazolyl)-2,2'-dimethyl-biphenyl Benzene (CDBP), 2-methyl-9,10-bis(naphthyl-2-yl)anthracene (MADN), bis[2-(diphenylphosphino)phenyl]ether oxide (DPEPO), hexaphenylcyclotriphosphazene (CP1), 1,4-bis(triphenylsilyl)benzene (UGH2), hexaphenylcyclotrisiloxane (DPSiO3), octaphenylcyclotetrasiloxane (DPSiO4), 2,8-bis(diphenylphospho)dibenzofuran (PPF), 3,3'-bis(N-carbazolyl)-1,1'-biphenyl (mCBP), and 1,3-bis(N-carbazolyl)benzene (mCP) are used as host materials. However, the examples are not limited to these and may include any suitable delayed fluorescence emission host material.

[0161] Furthermore, the emission layer EML in the organic electroluminescent device 10 of the embodiment may also include any suitable dopant material. In the embodiment, the emission layer EML may include styrene derivatives (e.g., 1,4-bis[2-(3-N-ethylcarbazolyl)vinyl]benzene (BCzVB), 4-(di-p-tolylamino)-4'-[(di-p-tolylamino)styrene]benzene (DPAVB) and N-(4-((E)-2-(6-((E)-4-(diphenylamino)styrene)naphth-2-yl)vinyl)phenyl)-N-phenylaniline (N-BDAVBi)), perylene and its derivatives (e.g., 2,5,8,11-tetra-tert-butylperylene (TBP)), pyrene and its derivatives (e.g., 1,1'-dipyrene, 1,4-dipyrenebenzene, 1,4-bis(N,N-diphenylamino)pyrene) as dopant materials.

[0162] Furthermore, in the embodiments, the emitter layer EML may include two dopant materials with different lowest triplet excitation energy levels (T1 level). The emitter layer EML of the organic electroluminescent device 10 in the embodiments may include a host having a first lowest triplet excitation energy level, a first dopant having a second lowest triplet excitation energy level lower than the first lowest triplet excitation energy level, and a second dopant having a third lowest triplet excitation energy level lower than the second lowest triplet excitation energy level. In the embodiments, the emitter layer EML may include the fused polycyclic compound described above as the first dopant.

[0163] In the organic electroluminescent device 10 of the embodiment, which includes a host, a first dopant, and a second dopant in the emitter layer EML, the first dopant may be a delayed fluorescence dopant, and the second dopant may be a fluorescent dopant. Furthermore, the fused polycyclic compound represented by Formula 1 in the organic electroluminescent device 10 of the embodiment may be used as an auxiliary dopant.

[0164] For example, when the emitter layer EML of the organic electroluminescent device 10 in the embodiment includes multiple dopants, the emitter layer EML may include the above-described fused polycyclic compound as the first dopant and one of the other dopant materials as the second dopant. In an embodiment, when the emitting layer EML emits blue light, the emitting layer EML may further include a dopant selected from any related technology of vinyl derivatives (e.g., 1,4-bis[2-(3-N-ethylcarbazolyl)vinyl]benzene (BCzVB), 4-(di-p-tolylamino)-4'-[(di-p-tolylamino)styryl]benzene (DPAVB) and N-(4-((E)-2-(6-((E)-4-(diphenylamino)styryl)naphth-2-yl)vinyl)phenyl)-N-phenylaniline (N-BDAVBi)), perylene and its derivatives (e.g., 2,5,8,11-tetra-tert-butylperylene (TBP)), pyrene and its derivatives (e.g., 1,1'-dipyrene, 1,4-dipyrenebenzene, 1,4-bis(N,N-diphenylamino)pyrene) as a second dopant. In addition, metal complexes or organometallic complexes, such as (4,6-F2ppy)2Irpic, which include Ir, Pt, Pd, etc. as core atoms, can also be used as second dopants.

[0165] In the organic electroluminescent device 10 of the embodiment in which the fused polycyclic compound of the embodiment is used as the first dopant of the emission layer EML, the emission layer EML can emit green light or red light, wherein the second dopant material can be the blue dopant, green fluorescent dopant or red fluorescent dopant of the above-mentioned related technologies.

[0166] When the emitter layer (EML) of the organic electroluminescent device 10 in the embodiment includes multiple dopants, the first dopant having a lowest triplet excitation energy level higher than that of another dopant (e.g., the second dopant) is a blue dopant of the aforementioned related art, and the second dopant having a lowest triplet excitation energy level lower than that of another dopant (e.g., the first dopant) can include the fused polycyclic compound of the aforementioned embodiment. In this case, the aforementioned styrene derivatives, perylene derivatives, pyrene derivatives, metal complexes, or organometallic complexes can be used as the first dopant.

[0167] The emission layer EML in the organic electroluminescent device 10 of the embodiment can be a phosphorescent emission layer. For example, a fused polycyclic compound according to the embodiment can be included in the emission layer EML as a phosphorescent host material.

[0168] exist Figures 1 to 4 In the organic electroluminescent device 10 of the illustrated embodiment, the electron transport region (ETR) is disposed on the emitter layer (EML). The electron transport region (ETR) may include, but is not limited to, at least one selected from the hole blocking layer (HBL), the electron transport layer (ETL), and the electron injection layer (EIL).

[0169] The electronic transport region (ETR) can have a multi-layer structure, which may consist of a single layer made of a single material, a single layer made of different materials, or multiple layers made of different materials.

[0170] For example, the electron transport region (ETR) may have a monolayer structure including an electron injection layer (EIL) or an electron transport layer (ETL), or a monolayer structure formed of an electron injection material and / or an electron transport material. In some embodiments, the ETR may have a monolayer structure formed of materials different from each other, or may have a structure of an electron transport layer (ETL) / electron injection layer (EIL) or a hole blocking layer (HBL) / electron transport layer (ETL) / electron injection layer (EIL), with each layer sequentially stacked from the emitter layer (EML), but the embodiments are not limited thereto. The ETR may have, for example, approximately to approximately The thickness.

[0171] Electron transport regions (ETRs) can be formed using various methods, such as vacuum deposition, spin coating, casting, Langmuir-Blodget (LB) methods, inkjet printing, laser printing, and laser-induced thermal imaging (LITI).

[0172] When the electron transport region (ETR) includes an electron transport layer (ETL), the ETR may include anthracene compounds. However, the embodiments are not limited thereto, and the ETR may include, for example, tris(8-hydroxyquinoline)aluminum (Alq3), 1,3,5-tris[(3-pyridyl)-benzene-3-yl]benzene, 2,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine, 2-(4-(N-phenylbenzimidazol-1-yl)phenyl)-9,10-dinaphthylanthracene, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline. Phosphoroline (Bphen), 3-(4-biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ), 4-(naphthyl-1-yl)-3,5-diphenyl-4H-1,2,4-triazole (NTAZ), 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (tBu-PBD), bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum (BAlq), bis(benzoquinoline-10-hydroxy)beryllium (Bebq2), 9,10-bis(naphthyl-2-yl)anthracene (ADN), or mixtures thereof. The thickness of the electron transport layer (ETL) can be approximately... to approximately For example, about to approximately When the thickness of the electron transport layer (ETL) meets the above range, satisfactory electron transport characteristics can be achieved without significantly increasing the driving voltage.

[0173] When the electron transport region (ETR) includes an electron injection layer (EIL), the ETR can be formed using metal halides (such as LiF, NaCl, CsF, RbCl, RbI, and / or CuI), lanthanides (such as Yb), metal oxides (such as Li₂O and / or BaO), lithium 8-hydroxyquinoline (Liq), etc., but the embodiments are not limited thereto. In some embodiments, the electron injection layer (EIL) can be formed from a mixture of an electron transport material and an organometallic salt. The organometallic salt can be a material having a band gap of about 4 eV or greater. For example, the organometallic salt can include metal acetates, metal benzoates, metal acetoacetates, metal acetylacetonates, and / or metal stearates. The thickness of the electron injection layer (EIL) can be about [missing information]. to approximately or about to approximately When the thickness of the electron injection layer (EIL) meets the above range, satisfactory electron injection characteristics can be achieved without significantly increasing the driving voltage.

[0174] As described above, the electron transport region (ETR) may include a hole blocking layer (HBL). The hole blocking layer (HBL) may include, but is not limited to, at least one of, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and 4,7-diphenyl-1,10-phenanthroline (Bphen).

[0175] The second electrode EL2 can be disposed on the electron transport region ETR. The second electrode EL2 can be a common electrode or a cathode electrode. The second electrode EL2 can be a transmission electrode, a transmission-reflection electrode, or a reflection electrode. When the second electrode EL2 is a transmission electrode, the second electrode EL2 can be formed of a transparent metal oxide (e.g., indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), and / or indium tin zinc oxide (ITZO), etc.).

[0176] When the second electrode EL2 is a transmissive or reflective electrode, it may include Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, compounds comprising them, mixtures comprising them (e.g., a mixture of Ag and Mg), or oxides comprising them. Optionally, the second electrode EL2 may have a multilayer structure including a reflective or transmissive layer and a transparent conductive layer formed of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), and / or indium tin zinc oxide (ITZO).

[0177] In some embodiments, the second electrode EL2 can be connected to an auxiliary electrode. When the second electrode EL2 is connected to the auxiliary electrode, the resistance of the second electrode EL2 can be reduced.

[0178] In some embodiments, the organic electroluminescent device 10 may include a buffer layer between the emitter layer (EML) and the electron transport region (ETR). The buffer layer may control the concentration of excitons generated in the emitter layer (EML). For example, the buffer layer may include a portion of the emitter layer (EML) material. The buffer layer may include the host material of the emitter layer (EML) material. In some embodiments, depending on the combination of the host material and dopant material included in the emitter layer (EML), the lowest triplet excitation energy level of the buffer layer material may be controlled to be higher than or equal to the lowest triplet excitation energy level of the second dopant, or in some embodiments, it may be controlled to be lower than or equal to the lowest triplet excitation energy level of the second dopant.

[0179] A capping layer CPL may also be provided on the second electrode EL2 of the organic electroluminescent device 10 in this embodiment. The capping layer CPL may include, for example, α-NPD, NPB, TPD, m-MTDATA, Alq3, CuPc, N4,N4,N4',N4'-tetra(biphenyl-4-yl)biphenyl-4,4'-diamine (TPD15), 4,4',4”-tris(carbazole-9-yl)triphenylamine (TCTA), etc.

[0180] The organic electroluminescent device 10 according to embodiments of the present disclosure may include the aforementioned fused polycyclic compound in the emitter layer EML disposed between the first electrode EL1 and the second electrode EL2 to exhibit high luminous efficiency characteristics. Furthermore, the fused polycyclic compound according to the embodiments may be a thermally activated delayed fluorescence dopant, and the emitter layer EML may include the fused polycyclic compound to emit thermally activated delayed fluorescence, thereby exhibiting high luminous efficiency characteristics.

[0181] In some embodiments, the organic layers other than the emitting layer EML may include the fused polycyclic compound described above as a material for the organic electroluminescent device 10. For example, the organic electroluminescent device 10 of the embodiments of this disclosure may also include the fused polycyclic compound described above in at least one organic layer disposed between the first electrode EL1 and the second electrode EL2 or in the capping layer CPL disposed on the second electrode EL2.

[0182] When compared with compounds of related technologies, the fused polycyclic compounds of the embodiments described above include two polycyclic rings containing nitrogen and boron atoms within the fused ring, as well as a fused polycyclic heterocyclic moiety (such as carbazole, dibenzofuran, and / or dibenzothiophene), and have a relatively small energy difference (ΔE) between the lowest triplet excitation level (T1 level) and the lowest singlet excitation level (S1 level). ST Therefore, when the above-mentioned fused polycyclic compound is used as a material for the organic electroluminescent device 10, the efficiency of the organic electroluminescent device 10 can be improved.

[0183] In the following, the fused polycyclic compound and the organic electroluminescent device 10 of the embodiments according to the present disclosure will be explained in more detail with reference to examples and comparative examples. Examples are provided to aid in understanding the present disclosure, and the scope of the present disclosure is not limited thereto.

[0184] [Example]

[0185] 1. Synthesis of fused polycyclic compounds

[0186] First, example methods for synthesizing fused polycyclic compounds according to the present embodiments will be described for compounds 3, 15, 24, 56, 58, 66, 74, 88, and 98. Furthermore, in the following description, the methods for synthesizing fused polycyclic compounds are provided as examples, but the synthesis methods according to the embodiments of this disclosure are not limited to the following examples.

[0187] (1) Synthesis of compound 3

[0188] The fused polycyclic compound 3 according to the embodiments can be synthesized, for example, by the following reaction.

[0189] (Synthesis of intermediate compound 3-1)

[0190] [Reaction 1-a]

[0191]

[0192] 2,7-Dibromo-9-phenyl-9H-carbazole (1 eq), 3-(9H-carbazole-9-yl)-5-(diphenylamino)phenol (2 eq), CuI (0.1 eq), 1,10-phenanthroline (0.2 eq), and K₂CO₃ (4 eq) were dissolved in DMF and stirred at approximately 160 °C for approximately 12 hours. After cooling, the solvent was removed under reduced pressure, and the result was washed three times with dichloromethane and water, followed by separation to obtain the organic layer. The obtained organic layer was dried over anhydrous MgSO₄ and then under reduced pressure. Intermediate compound 3-1 was obtained by column chromatography (yield: 45%).

[0193] (Synthesis of compound 3)

[0194] [Reaction 1-b]

[0195]

[0196] Intermediate compound 3-1 (1 eq) was dissolved in o-dichlorobenzene and then cooled to approximately 0 °C under a nitrogen atmosphere. BBr3 (16 eq) was slowly injected, followed by stirring at approximately 150 °C for 24 h. After cooling, triethylamine was added dropwise to slowly quench the reaction, followed by extraction in ethanol. The extracted reactants were purified by filtration. The resulting solid was filtered through a silica gel filter using toluene, and then purified again by recrystallization using toluene to obtain compound 3 (yield: 4%).

[0197] (2) Synthesis of compound 15

[0198] The fused polycyclic compound 15 according to the embodiments can be synthesized by, for example, the following reaction.

[0199] (Synthesis of intermediate compound 15-1)

[0200] [Reaction 2-a]

[0201]

[0202] 3-Bromo-5-(9H-carbazole-9-yl)-N,N-diphenylaniline (1 eq), aniline (1.5 eq), Pd2(dba)3 (0.05 eq), P(t-Bu)3 (0.1 eq), and sodium tert-butoxide (3 eq) were dissolved in toluene and stirred at about 100 °C for about 12 hours. The reaction mixture was cooled and washed three times with ethyl acetate and water, and then separated to obtain an organic layer. The obtained organic layer was dried over anhydrous MgSO4 and then under reduced pressure. Intermediate compound 15-1 (yield: 83%) was obtained by filtration through a silica gel filter and recrystallization.

[0203] (Synthesis of intermediate compound 15-2)

[0204] [Reaction 2-b]

[0205]

[0206] Intermediate compound 15-2 was obtained by reacting 2,7-dibromo-9-phenyl-9H-carbazole (1 eq), intermediate compound 15-1 (2 eq), Pd2(dba)3 (0.1 eq), P(t-Bu)3 (0.2 eq), and sodium tert-butoxide (5 eq) in the same manner as in reaction formula 2-a (yield: 71%).

[0207] (Synthesis of compound 15)

[0208] [Reaction 2-c]

[0209]

[0210] Compound 15 was obtained by reacting intermediate compound 15-2 in the same manner as the synthesis and purification in reaction formula 1-b (yield: 17%).

[0211] (3) Synthesis of compound 24

[0212] The fused polycyclic compound 24 according to the embodiments can be synthesized by, for example, the following reaction.

[0213] (Synthesis of intermediate compound 24-1)

[0214] [Reaction 3-a]

[0215]

[0216] Intermediate compound 24-1 was obtained by reacting 2,7-dibromodibenzo[b,d]furan (1 eq) and 3-(9H-carbazol-9-yl)-5-(1,2,3,4-tetrahydroquinoline-1(2H)-yl)phenol (2 eq) in the same manner as in reaction formula 1-a (yield: 33%).

[0217] (Synthesis of compound 24)

[0218] [Reaction 3-b]

[0219]

[0220] Compound 24 was obtained by reacting intermediate compound 24-1 in the same manner as the synthesis and purification in reaction formula 1-b (yield: 16%).

[0221] (4) Synthesis of compound 56

[0222] The fused polycyclic compound 56 according to the embodiments can be synthesized, for example, by the following reaction.

[0223] (Synthesis of intermediate compound 56-1)

[0224] [Reaction 4-a]

[0225]

[0226] Intermediate compound 56-1 was obtained by reacting 2,7-dibromo-9-phenyl-9H-carbazole (1 eq) and 9-phenyl-9H-carbazole-2-ol (2 eq) in the same manner as in reaction formula 1-a (yield: 43%).

[0227] (Synthesis of compound 56)

[0228] [Reaction 4-b]

[0229]

[0230] Intermediate compound 56-1 (1 eq) was dissolved in o-xylene and then cooled to approximately 0 °C under a nitrogen atmosphere. BBr3 (12 eq) was slowly injected, followed by stirring at approximately 170 °C for 48 h. After cooling, compound 56 (yield: 6%) was obtained by the same purification process as in reaction 1-b.

[0231] (5) Synthesis of compound 58

[0232] The fused polycyclic compound 58 according to the embodiments can be synthesized, for example, by the following reaction.

[0233] (Synthesis of intermediate compound 58-1)

[0234] [Reaction 5-a]

[0235]

[0236] Intermediate compound 58-1 was obtained by reacting 2,7-dibromo-9-phenyl-9H-carbazole (1 eq) and N,9-diphenyl-9H-carbazole-2-amine (2 eq) in the same manner as in reaction formula 1-a (yield: 75%).

[0237] (Synthesis of compound 58)

[0238] [Reaction 5-b]

[0239]

[0240] Compound 58 was obtained by reacting intermediate compound 58-1 in the same manner as the synthesis and purification in reaction formula 1-b (yield: 12%).

[0241] (6) Synthesis of compound 66

[0242] The fused polycyclic compound 66 according to the embodiments can be synthesized by, for example, the following reaction.

[0243] (Synthesis of intermediate compound 66-1)

[0244] [Reaction 6-a]

[0245]

[0246] Intermediate compound 66-1 was obtained by reacting 2,7-dibromo-9-phenyl-9H-carbazole (1 eq) and 3,5-bis(diphenylamino)phenol (2 eq) in the same manner as in reaction formula 1-a (yield: 35%).

[0247] (Synthesis of compound 66)

[0248] [Reaction 6-b]

[0249]

[0250] Compound 66 was obtained by reacting intermediate compound 66-1 in the same manner as in reaction formula 1-b (yield: 35%).

[0251] (7) Synthesis of compound 74

[0252] The fused polycyclic compound 74 according to the embodiments can be synthesized, for example, by the following reaction.

[0253] (Synthesis of intermediate compound 74-1)

[0254] [Reaction 7-a]

[0255]

[0256] Intermediate compound 74-1 was obtained by reacting 2,7-dibromo-9-phenyl-9H-carbazole (1 eq) and N1,N1,N3,N3,N5-pentaphenylbenzene-1,3,5-triamine (2 eq) in the same manner as in reaction formula 1-a (yield: 73%).

[0257] (Synthesis of compound 74)

[0258] [Reaction 7-b]

[0259]

[0260] Compound 74 was obtained by reacting intermediate compound 74-1 in the same manner as the synthesis and purification in reaction formula 1-b (yield: 18%).

[0261] (8) Synthesis of compound 88

[0262] The fused polycyclic compound 88 according to the embodiments can be synthesized by, for example, the following reaction.

[0263] (Synthesis of intermediate compound 88-1)

[0264] [Reaction 8-a]

[0265]

[0266] Intermediate compound 88-1 was obtained by reacting 2,7-dibromodibenzo[b,d]furan (1 eq) and 3,5-bis(1,2,3,4-tetrahydroquinoline-1(2H)-yl)-N-phenylaniline (2 eq) in the same manner as in reaction formula 1-a (yield: 55%).

[0267] (Synthesis of compound 88)

[0268] [Reaction 8-b]

[0269]

[0270] Compound 88 was obtained by reacting intermediate compound 88-1 in the same manner as the synthesis and purification in reaction formula 1-b (yield: 10%).

[0271] (9) Synthesis of compound 98

[0272] The fused polycyclic compound 98 according to the embodiments can be synthesized, for example, by the following reaction.

[0273] (Synthesis of intermediate compound 98-1)

[0274] [Reaction 9-a]

[0275]

[0276] Intermediate compound 98-1 was obtained by reacting 2,7-dibromodibenzo[b,d]thiophene (1 eq) and N1,N1,N3,N3,N5-pentaphenylbenzene-1,3,5-triamine (2 eq) in the same manner as in reaction formula 1-a (yield: 61%).

[0277] (Synthesis of compound 98)

[0278] [Reaction 9-b]

[0279]

[0280] Compound 98 was obtained by reacting intermediate compound 98-1 in the same manner as the synthesis and purification in reaction formula 1-b (yield: 4%).

[0281] Compounds 3, 15, 24, 56, 58, 66, 74, 88, and 98 1 H-NMR measurements and molecular weight data are shown in Table 1. Therefore, it can be confirmed that the compounds prepared by each synthetic example are compound 3, compound 15, compound 24, compound 56, compound 58, compound 66, compound 74, compound 88 and compound 98, respectively.

[0282] [Table 1]

[0283]

[0284]

[0285] 2. Evaluation of energy levels in fused polycyclic compounds

[0286] The energy levels of Example Compound 1, Example Compound 3, Example Compound 6, Example Compound 15, and Example Compound 56, as well as Comparative Compounds C1 and C2, were identified through simulation (computation). The calculated energy levels of the example and comparative compounds are as follows:

[0287]

[0288] The HOMO level, LUMO level, lowest singlet excitation level (S1 level), lowest triplet excitation level (T1 level), dipole momentum, oscillator strength (OSC), and ΔE of example compounds 1, 3, 6, 15, and 56, and comparative compounds C1 and C2. ST The values ​​for the energy levels in Table 2 are listed. The values ​​in Table 2 were calculated using non-empirical molecular orbital methods. For example, this value was calculated using Gaussian 09 from Gaussian, Inc. (Wallingford, CT, USA) with B3LYP / 6-31G(d). ΔE ST The difference between the lowest singlet excitation level (S1 level) and the lowest triplet excitation level (T1 level) is shown.

[0289] [Table 2]

[0290]

[0291] It can be determined that, compared with comparative compounds C1 and C2, example compounds 1, 3, 6, 15, and 56 have higher T1 energy levels and lower ΔE. ST Values ​​and higher oscillator strength values. Each of Example Compound 1, Example Compound 3, Example Compound 6, Example Compound 15, and Example Compound 56 has a low ΔE value of 0.33 eV or lower. ST The high oscillator intensity values ​​improve light absorption properties. Therefore, these compounds have been found to be suitable as thermally activated delayed fluorescence dopants.

[0292] 3. Fabrication and evaluation of organic electroluminescent devices, including fused polycyclic compounds (Fabrication of organic electroluminescent devices)

[0293] The following describes the fabrication of organic electroluminescent devices comprising the fused polycyclic compounds of the embodiments in the emitter layer. Compounds 3, 15, 24, 56, 58, 66, 74, 88, and 98, as example fused polycyclic compounds, were used as dopant materials in the emitter layer to fabricate organic electroluminescent devices of Examples 1 to 9. Comparative Examples 1 and 2 correspond to organic electroluminescent devices fabricated using comparative compounds C2 and C3 as dopant materials in the emitter layer.

[0294] To form the first electrode, a material with approximately 15 Ω / cm will be manufactured by Corning Inc. 2 (about The ITO glass substrate was cut to a size of 50mm × 50mm × 0.7mm, washed with isopropanol and pure water for about 5 minutes, ultrasonically cleaned, then irradiated with ultraviolet light for about 30 minutes and exposed to ozone for cleaning. The glass substrate was mounted in a vacuum deposition apparatus. NPD was deposited on top of the glass substrate under vacuum to approximately [size missing]. The thickness is such that a hole injection layer is formed, and TCTA as a hole transport compound is deposited under vacuum to approximately [amount missing]. The thickness is adjusted to form a hole transport layer. CzSi is deposited on the hole transport layer under vacuum to approximately [thickness value missing]. The thickness. mCP and the example compound of this disclosure, or mCP and the comparative compound, are co-deposited on the hole transport layer at a weight ratio of 99:1 to form a layer with approximately... An emission layer of approximately [thickness missing]. Then, TSPO1, a compound used as an electron transport layer, is formed to approximately [thickness missing]. The thickness, and the TPBi compound deposited as the electron injection layer to The thickness is approximately [missing information]. LiF, as an alkali metal halide, is deposited on the electron transport layer to approximately [missing information]. The thickness, and Al deposited under vacuum to approximately The thickness is increased to form the LiF / Al second electrode, thereby fabricating an organic electroluminescent device.

[0295] The compounds used to manufacture the example and comparative examples of organic electroluminescent devices are shown below.

[0296]

[0297]

[0298] (Performance evaluation of organic electroluminescent devices)

[0299] The evaluation results of the organic electroluminescent devices of Examples 1 to 9, Comparative Examples 1 and 2 are listed in Table 3. The driving voltage, luminous efficiency, and external quantum efficiency (EQE) of the fabricated organic electroluminescent devices are listed in Table 3 for comparison.

[0300] In the evaluation results of the example and comparative examples shown in Table 3, voltage and current densities were measured using a SourceMeter (2400 series, Keithley Instrument, Solon, Ohio, USA), and external quantum efficiency (EQE) was measured using an external quantum efficiency measurement system (C9920-12) from Hamamatsu Photonics (Hamamatsu, Shizuoka, Japan). Luminous efficiency is expressed in 10 mA / cm². 2 The current efficiency value at the given current density.

[0301] [Table 3]

[0302]

[0303] Referring to the results in Table 3, it can be seen that, compared with the devices of the comparative examples, the example organic electroluminescent devices using the fused polycyclic compounds according to embodiments of the present disclosure as the emitter layer material all emit blue light and exhibit low driving voltage, relatively high brightness, and high luminous efficiency. Without being bound by the correctness of any theory or explanation, the example compounds exhibit TADF properties due to their structural properties (including the aromatic rings forming the fused rings, e.g., two polycyclic rings containing nitrogen and boron atoms, and the fused polycyclic heterocyclic moieties (such as carbazole, dibenzofuran, and / or dibenzothiophene)) through multiple resonance phenomena, allowing the example compounds to exhibit multiple resonances in a broad planar framework compared to comparative compounds C3 and C2. Therefore, the example organic electroluminescent devices can exhibit improved luminous efficiency compared to the organic electroluminescent devices of the comparative examples.

[0304] The fused polycyclic compound of the embodiment comprises two polycyclic rings containing nitrogen and boron atoms, and has a fused polycyclic heterocyclic moiety in the compound, and thus has a high oscillator strength value and low ΔE. ST The fused polycyclic compounds of the embodiments can be used as dopant materials in the emission layer of organic electroluminescent devices to improve device efficiency.

[0305] The organic electroluminescent devices of the embodiments may include the fused polycyclic compounds of the embodiments to exhibit improved luminous efficiency. Furthermore, by including the fused polycyclic compounds of the embodiments as the emitting layer material, the organic electroluminescent devices of the embodiments can achieve high luminous efficiency in the blue light wavelength region.

[0306] Organic electroluminescent devices according to embodiments of this disclosure can exhibit improved device properties, such as low driving voltage and high efficiency.

[0307] The fused polycyclic compounds of the embodiments can be included in the emitting layer of the organic electroluminescent device, thereby contributing to the high efficiency of the organic electroluminescent device.

[0308] Although the foregoing has been described with reference to various embodiments of the present disclosure, it will be understood that various changes and modifications may be made to the present disclosure by those skilled in the art or of ordinary skill in the art without departing from the spirit and technical field of the present disclosure as set forth in the claims and their equivalents.

[0309] Therefore, the technical scope of this disclosure is not limited to the specification, but should be determined solely by referring to the claims and their equivalents.

Claims

1. An organic electroluminescent device, the organic electroluminescent device comprising: First electrode; The hole transport region is located on the first electrode; The emission layer is located on the hole transport region; The electron transmission region is located on the emission layer; as well as The second electrode is located on the electron transport region. The first electrode and the second electrode each independently include at least one selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn, or two or more selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn. More compounds, mixtures of two or more selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn, or oxides of one or more selected from Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, In, Sn, and Zn, and The emission layer comprises a fused polycyclic compound represented by the following formula 1: [Formula 1] In Equation 1, X1 to X3 are all independently NR9, O or S, and X2 and X3 are the same. Y1 to Y4 are all independent direct-connect keys. Both R1 and R4 are independently hydrogen atoms, unsubstituted alkyl groups having 1 to 20 carbon atoms, substituted or unsubstituted diphenylamino groups, substituted or unsubstituted isopropylaniline groups, or substituted or unsubstituted tetrahydroquinoline groups. R2, R3, R5, and R6 are each independently a hydrogen atom or an unsubstituted alkyl group having 1 to 20 carbon atoms. R 11 and R 12 Each is independently an unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted phenyl group, or is combined with an adjacent group to form a ring. R9 is a substituted or unsubstituted phenyl group. n1 to n4 are all independent integers from 0 to 2. n5 and n6 are both independent integers from 0 to 3, and m1 to m4 are all independently 0 or 1, m1 and m3 are the same, and m2 and m4 are the same. Wherein, substitution means substitution with an alkyl group having 1 to 20 carbon atoms.

2. The organic electroluminescent device according to claim 1, wherein, The absolute value of the difference between the lowest singlet excitation energy level of the fused polycyclic compound represented by Formula 1 and the lowest triplet excitation energy level of the fused polycyclic compound represented by Formula 1 is 0.33 eV or less.

3. The organic electroluminescent device according to claim 1, wherein, In Equation 1, When Y1 is a direct-connect key, m1 is 1. When Y2 is a direct-connect key, m2 is 1. When Y3 is a direct-connect key, m3 is 1, and When Y4 is a direct key, m4 is 1.

4. The organic electroluminescent device according to claim 1, wherein, The fused polycyclic compound represented by Formula 1 is represented by Formula 1-1: [Equation 1-1] In Equation 1-1, Both R7 and R8 are independently hydrogen atoms or unsubstituted alkyl groups having 1 to 20 carbon atoms. n7 and n8 are both independent integers from 0 to 3, and X1 to X3, Y1 to Y4, R1 to R6, n1 to n6, and m1 to m4 are all independently identical to those defined in Equation 1.

5. The organic electroluminescent device according to claim 4, wherein, The fused polycyclic compound represented by Formula 1-1 is represented by Formula 2-1 or Formula 2-2: [Equation 2-1] [Equation 2-2] In equations 2-1 and 2-2, X1 to X3, Y1 to Y4, R1 to R8, n1 to n8, and m1 to m4 are all independently identical to those defined in Equation 1-1.

6. The organic electroluminescent device according to claim 4, in, The fused polycyclic compound represented by Formula 1-1 is represented by Formula 3-1 or Formula 3-2: [Equation 3-1] [Equation 3-2] In equations 3-1 and 3-2, X1 to X3, R1 to R8, and n1 to n8 are all independently identical to those defined in Equation 1-1.

7. The organic electroluminescent device according to claim 4, wherein, The fused polycyclic compound represented by Formula 1-1 is represented by Formula 4: [Formula 4] In Equation 4, X1 to X3, Y1 to Y4, R1, R4, R5, R6, R7, R8 and m1 to m4 are all independently identical to those defined in Equation 1-1.

8. The organic electroluminescent device according to claim 1, wherein, In Formula 1, when X1 to X3 are all NR9, R9 is an unsubstituted phenyl group.

9. The organic electroluminescent device according to claim 1, wherein, The fused polycyclic compound includes at least one compound selected from compounds of group 1 and group 2: [Compound Group 1] [Compound Group 2] 10. The organic electroluminescent device according to claim 1, wherein, The emission layer emits delayed fluorescence.

11. The organic electroluminescent device according to claim 1, in, The emission layer is a delayed fluorescence emission layer comprising a host and dopants, and The dopant is the fused polycyclic compound.

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