Organic electroluminescent device

Abstract

Provided are organic electroluminescent devices exhibiting high light emission efficiency, the organic electroluminescent devices including a first electrode, a second electrode, and an emission layer disposed between the first electrode and the second electrode. The emission layer can include a compound represented by Formula 1.[Formula 1]

Description

[0001] Cross-references to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2020-0052327, filed on April 29, 2020, with the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to compounds used as luminescent materials and organic electroluminescent devices including the same. Background Technology

[0004] Recently, organic electroluminescent displays (OLEDs) have been under active development as image display devices. Compared with liquid crystal displays (LCDs), OLEDs are so-called self-emissive display devices, in which holes and electrons injected from the first and second electrodes recombine in the emitting layer, and thus the emitting layer contains luminescent materials of organic compounds to emit light to achieve display.

[0005] In the application of organic electroluminescent devices in display devices, there is a continuous demand for organic electroluminescent devices with low driving voltage, high light emission efficiency and long lifespan, as well as a continuous demand for developing materials for organic electroluminescent devices that can stably obtain these characteristics.

[0006] In recent years, in order to realize efficient organic electroluminescent devices, technologies related to phosphorescence emission using triplet energy or delayed fluorescence using triplet-triplet annihilation (TTA) (where singlet excitons are generated through collisions of triplet excitons) are being developed, and thermally activated delayed fluorescence (TADF) materials using the delayed fluorescence phenomenon are also being developed. Summary of the Invention

[0007] This disclosure provides an organic electroluminescent device that demonstrates excellent light emission efficiency.

[0008] This disclosure also provides a compound that is a material for an organic electroluminescent device that emits deep blue light and has high efficiency.

[0009] Embodiments of this invention provide compounds represented by Formula 1:

[0010]

[0011]

[0012] In Equation 1, X1 and X2 can each be independently O or S, and L1 to L 11 At least one of them may be a substituent represented by formula 2-a or formula 2-b, L1 to L 11The remaining part may be, independently, a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted silyl group, a substituted or unsubstituted boron group, a substituted or unsubstituted straight-chain or branched 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.

[0013]

[0014] In equations 2-a and 2-b, R1 to R 24 Each of the following can be independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted silyl group, a substituted or unsubstituted boron 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. Ar1 and Ar2 can each independently be 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, and Ar3 can be 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, a substituted or unsubstituted heteroaryl group having 2 to 30 cyclic carbon atoms, or a substituent represented by Formula 1. When Ar3 is a substituent represented by Formula 1, L1 to L2 in Ar3... 11 Each of the following can be independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted silyl group, a substituted or unsubstituted boron group, a substituted or unsubstituted straight-chain or branched 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.

[0015] This refers to the binding site with adjacent atoms.

[0016] In the implementation, equation 1 can be represented by one of equations 1-1 to 1-3:

[0017]

[0018] In equations 1-1 to 1-3, L1 to L 11 It can be the same as that specified in Equation 1.

[0019] In the implementation, equation 1 can be represented by one of equations 1A to 1E:

[0020]

[0021] In Equations 1A to 1E, a to c can each be an integer selected from 0 to 3 independently, X1 and X2 can be the same as those defined in Equation 1, and L a To L c and L1 to L 11 Each of the following can be independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted silyl group, a substituted or unsubstituted boron group, a substituted or unsubstituted straight-chain or branched 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, and DU can be represented by formula 2-a or formula 2-b.

[0022] In the implementation, equation 1 can be represented by equation 1F:

[0023]

[0024]

[0025] In Equation 1F, R9 to R 24 As defined in Formula 2-b, AU can be a substituent represented by Formula 1, except that AU may not be substituted by a substituent represented by Formula 2-a or Formula 2-b.

[0026] In the implementation, equation 1 can be represented by one of equations 1F-1 to 1F-3:

[0027]

[0028]

[0029] In equations 1F-1 to 1F-3, L1 to L 11 Each of the following can be independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted silyl group, a substituted or unsubstituted boryl group, a substituted or unsubstituted straight-chain or branched 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. X1 and X2 can be the same as those defined in Formula 1, and R9 to R 24 It can be the same as that defined in Equation 2-b.

[0030] In an embodiment, in Formula 1, at least one hydrogen atom may be replaced by a deuterium atom.

[0031] In the embodiments, in Formula 1, Ar1 and Ar2 can each be independently an unsubstituted phenyl, a phenyl substituted with a deuterium atom, an unsubstituted biphenyl, an unsubstituted naphthyl or an unsubstituted dibenzothiophene.

[0032] In the embodiments, the compound represented by Formula 1 may be a blue luminescent material.

[0033] In the embodiments, the compound represented by Formula 1 may be a thermally activated delayed fluorescence emission material.

[0034] Another embodiment of the present invention provides an organic electroluminescent device, the organic electroluminescent device comprising a first electrode, a second electrode disposed on the first electrode, and an emitting layer disposed between the first electrode and the second electrode. The emitting layer may comprise a compound represented by Formula 1.

[0035] In an embodiment, the organic electroluminescent device may further include a capping layer disposed on the second electrode, and the capping layer may have a refractive index greater than or equal to about 1.6.

[0036] In an embodiment, the emission layer may be a delayed fluorescence emission layer containing a host and a dopant, and the dopant may include a compound represented by Formula 1.

[0037] In one embodiment, the emitting layer may emit blue light having a center wavelength in the range of about 430 nm to about 490 nm. Attached Figure Description

[0038] 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 embodiments of the inventive concept and, together with the description, serve to explain the principles of the inventive concept. In the drawings:

[0039] Figure 1 A schematic cross-sectional view illustrating an organic electroluminescent device according to an embodiment of the present invention;

[0040] Figure 2 A schematic cross-sectional view illustrating an organic electroluminescent device according to an embodiment of the present invention;

[0041] Figure 3 A schematic cross-sectional view illustrating an organic electroluminescent device according to an embodiment of the present invention; and

[0042] Figure 4 A schematic cross-sectional view illustrating an organic electroluminescent device according to an embodiment of the present invention. Detailed Implementation

[0043] The inventive concept can be modified in various ways and can be embodied in different forms, and exemplary embodiments will be explained in detail with reference to the accompanying drawings. However, the inventive concept can be embodied in different forms and should not be construed as being limited to the embodiments set forth herein. Rather, all modifications, equivalents, and alternatives that fall within the spirit and scope of the inventive concept should be included in the inventive concept.

[0044] In the description, it should be understood that when an element (region, layer, or part, etc.) is referred to as being "on" another element, "connected to" or "attached to" another element, it may be directly on, directly connected to or attached to the other element, or an intermediate third element may be disposed between them.

[0045] Throughout the specification, the same reference numerals refer to the same elements. In the drawings, the thickness, scale, and dimensions of the elements may be enlarged for effective description of the technical content.

[0046] As used herein, the term “and / or” includes any and all combinations of one or more of the related listed items. For example, “A and / or B” can be understood to mean “A, B, or A and B”. The terms “and” and “or” can be used to connect or separate meanings and can be understood as equivalent to “and / or”. Throughout the disclosure, the expression “at least one of A, B, and C” can indicate only A, only B, only C, both A and B, both A and C, both B and C, all A, B, and C, or variations thereof.

[0047] For purposes of meaning and interpretation, the term "at least one of..." is intended to include the meaning of "selected from at least one of...". For example, "at least one of A and B" can be understood to mean "A, B, or A and B". When following a list of elements, the term "at least one of..." modifies the entire list of elements and does not modify any individual element in the list.

[0048] It should be understood that while 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 used only to distinguish one element from another. For example, a first element may be referred to as a second element without departing from the scope of embodiments of the inventive concept, and similarly, a second element may be referred to as a first element. Singular terms may include plural forms unless the context clearly indicates otherwise.

[0049] The terms "below," "down," "above," and "upper," etc., are used to describe the relationships of the configurations shown in the accompanying drawings. These terms are used as relative concepts and are described with reference to the directions indicated in the accompanying drawings.

[0050] Taking into account the measurements discussed and the errors associated with the measurement of the quantities (i.e., limitations of the measurement system), the terms “about” or “approximately” as used herein include stated values ​​and mean within an acceptable range of deviation from the stated values ​​as determined by one of ordinary skill in the art. For example, “about” may mean within one or more standard deviations, or within ±20%, ±10%, or ±5% of the stated value.

[0051] Unless otherwise specified, 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 the inventive concept pertains. It should also be understood that terms defined in common dictionaries shall be interpreted as having a meaning consistent with their meaning in the context of the relevant field, and are expressly defined herein, unless they are interpreted in an ideal or overly formal sense.

[0052] It should be understood that the terms “comprises,” “comprising,” “includes,” “including,” “have,” “having,” “contains,” and / or “containing” are intended to specify the presence of a feature, integer, step, operation, element, component, or combination thereof described in this disclosure, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

[0053] In the following description, an organic electroluminescent device according to an embodiment of the present invention and compounds including those embodiments will be described with reference to the accompanying drawings.

[0054] Figures 1 to 4 A schematic cross-sectional view illustrating an organic electroluminescent device according to an embodiment of the present invention. (Reference) Figures 1 to 4 In each organic electroluminescent device 10 according to the embodiment, the first electrode EL1 and the second electrode EL2 are arranged to face each other, and the emission layer EML may be disposed between the first electrode EL1 and the second electrode EL2.

[0055] In addition to the emitter layer EML, each organic electroluminescent device 10 of the embodiments may further include a functional layer between the first electrode EL1 and the second electrode EL2. The functional layer may include a hole transport region HTR and an electron transport region ETR. For example, each organic electroluminescent device 10 according to the embodiments 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 that can be stacked sequentially. The organic electroluminescent device 10 of the embodiments may include a capping layer CPL disposed on the second electrode EL2.

[0056] The organic electroluminescent device 10 of the embodiment may include the compound according to the following embodiment in the emitter layer EML disposed between the first electrode EL1 and the second electrode EL2. However, the embodiment is not limited thereto, and the organic electroluminescent device 10 of the embodiment may include the compound according to the following embodiment in the hole transport region HTR or the electron transport region ETR and in the emitter layer EML, wherein the hole transport region HTR or the electron transport region ETR is one of the functional layers disposed between the first electrode EL1 and the second electrode EL2.

[0057] and Figure 1 compared to, Figure 2 A schematic cross-sectional view of the organic electroluminescent device 10 according to an embodiment is provided, 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 schematic cross-sectional view of the organic electroluminescent device 10 according to an embodiment is provided, 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 schematic cross-sectional view of an organic electroluminescent device 10, including a capping layer CPL disposed on a second electrode EL2, is shown.

[0058] The first electrode EL1 is conductive. The first electrode EL1 may be formed of a metal alloy or a conductive compound. The first electrode EL1 may be an anode. The first electrode EL1 may be a pixel electrode. The first electrode EL1 may be a transmissive electrode, a transmissive-reflective electrode, or a reflective electrode. When the first electrode EL1 is a transmissive electrode, it may include a transparent metal oxide, such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), and indium tin zinc oxide (ITZO). When the first electrode EL1 is a transmissive-reflective electrode or a reflective electrode, it may include at least one material selected from the group consisting of Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF, Mo, Ti, compounds thereof, and mixtures thereof (e.g., a mixture of Ag and Mg). In other embodiments, the first electrode EL1 may have a multilayer structure, comprising a reflective layer or a transmissive-reflective layer formed of the above materials, and a transparent conductive layer formed of ITO, IZO, ZnO, ITZO, etc. For example, the first electrode EL1 may have a three-layer structure of ITO / Ag / ITO, but is not limited to this. The thickness of the first electrode EL1 can be approximately... to approximately Within a certain range. For example, the thickness of the first electrode EL1 can be approximately... to approximately Within the range.

[0059] A hole transport region (HTR) may be provided on the first electrode EL1. The 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. The thickness of the HTR may, for example, be approximately [thickness value missing]. to approximately Within the range.

[0060] The hole transport region (HTR) can have a single layer formed of a single material, a single layer formed of different materials, or a multilayer structure including layers formed of different materials.

[0061] For example, the hole transport region HTR may have a single-layer structure of a hole injection layer HIL or a hole transport layer HTL, and may have a single-layer structure formed of a hole injection material and a hole transport material. The hole transport region HTR may have a single-layer structure formed of different materials, or may have a structure in which the hole injection layer HIL / hole transport layer HTL / hole buffer layer (not shown), hole injection layer HIL / hole buffer layer (not shown), hole transport layer HTL / hole buffer layer, or hole injection layer HIL / hole transport layer HTL / electron blocking layer EBL are stacked sequentially from the first electrode EL1, but the implementation is not limited to this.

[0062] Hole transport regions (HTRs) can be formed using various methods such as vacuum deposition, spin coating, casting, Langmuir-Brookett (LB) method, inkjet printing, laser printing, and laser-induced thermal imaging (LITI).

[0063] Hole injection layer HIL may include, for example, phthalocyanine compounds such as copper phthalocyanine, N,N'-diphenyl-N,N'-bis-[4-(phenyl-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”-tris{N-(2-naphthyl)-N-phenylamino}-triphenylamine (2-TNATA), poly(3,4-ethylenedioxythiophene) / poly(4-phenylethyl) Poly(phenylene 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)borate, dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexaonitrile (HAT-CN), etc.

[0064] Hole transport layers (HTLs) may include, for example, carbazole derivatives such as N-phenylcarbazole and polyvinylcarbazole, fluorene derivatives, N4,N4'-bis(naphthyl-1-yl)-N4,N4'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (α-NPD), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (TPD), and triphenylamine derivatives such as 4,4'- ,4”-tris(N-carbazole-9-yl)triphenylamine (TCTA), N,N'-di(naphthyl-1-yl)-N,N'-diphenyl-benzidine (NPB), 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline] (TAPC), 4,4'-bis[N,N'-(3-tolyl)amino]-3,3'-dimethylbiphenyl (HMTPD), 1,3-bis(N-carbazole)benzene (mCP), etc.

[0065] The electron blocking layer (EBL) may include, for example, 9-phenyl-9H-3,9'-bicarbazole (CCP), 1,3-bis(N-carbazolyl)benzene (mCP), 1,3-bis(1,8-dimethyl-9H-carbazol-9-yl)benzene (mDCP), etc.

[0066] The thickness of the hole transport region (HTR) can be approximately to approximately Within a certain range. For example, the thickness of the hole transport region (HTR) can be approximately... to approximately Within a certain range. The thickness of the hole injection layer (HIL) can be, for example, approximately... to approximately Within a certain range, and the thickness of the hole transport layer (HTL) can be approximately... to approximately Within a certain range. For example, the thickness of the electron blocking layer (EBL) can be approximately... to approximately Within the specified range. If the thicknesses of the hole transport region (HTR), hole injection layer (HIL), hole transport layer (HTL), and electron blocking layer (EBL) meet the above range, satisfactory hole transport characteristics can be achieved without significantly increasing the driving voltage.

[0067] The hole transport region (HTR) may further include a charge-generating material to increase 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 at least one of, but is not limited to, quinone derivatives, metal oxides, and cyano-containing compounds. For example, non-limiting examples of p-dopers may include, but are not limited to, 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.

[0068] As described above, in addition to the hole injection layer HIL and the hole transport layer HTL, the hole transport region HTR may further include at least one of a hole buffer layer (not shown) and an electron blocking layer EBL. The hole buffer layer (not shown) can compensate for the resonant distance according to the wavelength of light emitted from the emitter layer EML and can increase the light emission efficiency. Materials that can be included in the hole transport region HTR can be used as materials that can be included in the hole buffer layer (not shown). The electron blocking layer EBL is a layer that can be used to prevent electrons from being injected from the electron transport region ETR into the hole transport region HTR.

[0069] The emitter layer EML is provided on the hole transport region HTR. The thickness of the emitter layer EML can be approximately... to approximately Within a certain range. For example, the thickness of the emitter layer EML can be approximately... to approximately Within the range. The emitter layer (EML) can have a single layer formed of a single material, a single layer formed of different materials, or a multilayer structure with layers formed of different materials.

[0070] The emission layer EML in the organic electroluminescent device 10 of the embodiment may include the compound of the embodiment.

[0071] The compounds according to embodiments may include at least one azasiline unit and at least one fused-ring unit containing a boron atom (B). In the compounds according to embodiments, in addition to the boron atom, the fused-ring unit may include two heteroatoms selected from oxygen (O) and sulfur (S). In the compounds of embodiments, the fused-ring unit may have a structure in which five six-membered rings are fused, and the heteroatoms may include boron atoms.

[0072] In the compounds of the embodiments, the nitrosilane unit may include a nitrosilane moiety, or may have a helical structure in which two nitrosilane moieties are bonded.

[0073] The compounds of the embodiments may include a fused ring unit containing a boron atom as an electron acceptor and a nitrosilane unit as an electron donor. The compounds of the embodiments may have a structure in which at least one electron acceptor and at least one electron donor are bonded.

[0074] In the description, the term "substituted or unsubstituted" may indicate that the substance is unsubstituted or substituted with at least one substituent selected from the group consisting of: deuterium, halogen, cyano, nitro, amino, silyl, oxy, thio, sulfinyl, sulfonyl, carbonyl, boron, phosphonyl oxide, phosphonyl sulfide, alkyl, alkenyl, alkynyl, cycloalkyl, aryl, and heterocyclic. Each of the above substituents may be substituted or unsubstituted. For example, biphenyl may be interpreted as aryl, or a phenyl substituted with a phenyl group. Thio groups include alkylthio and arylthio groups, and oxy groups include alkoxy and aryloxy groups.

[0075] Examples of halogen atoms in the description may include fluorine, chlorine, bromine, and iodine atoms.

[0076] In the description, alkyl groups may be straight-chain, branched, or cyclic. The number of carbons in the alkyl group is 1 to 50, 1 to 30, 1 to 20, 1 to 10, or 1 to 6. Examples of alkyl groups may include, but are not limited to, 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.

[0077] In this description, aryl means any functional group or substituent derived from an aromatic hydrocarbon ring. Aryl groups can be monocyclic or polycyclic. The number of cyclic carbon atoms in an aryl group can be 6 to 30, 6 to 20, or 6 to 15. Examples of aryl groups include, but are not limited to, phenyl, naphthyl, fluorenyl, anthraceneyl, phenanthryl, biphenyl, terphenyl, tetraphenyl, pentaphenyl, hexaphenyl, triphenylene, pyrene, benzofluoranthracene, 1,2-benzophenanthryl, etc.

[0078] In the description, a heteroaryl group may include at least one of B, O, N, P, Si, and S as a heteroatom. When a heteroaryl group contains two or more heteroatoms, the two or more heteroatoms may be the same or different from each other. The heteroaryl group may be a monocyclic heteroaryl or a polycyclic heteroaryl. The number of cyclic carbon atoms in the heteroaryl group may be 2 to 30, 2 to 20, or 2 to 10. Examples of heteroaryl groups may include, but are not limited to, thienyl, furanyl, pyrrolyl, imidazolyl, thiazolyl, oxazolyl, oxadiazolyl, triazolyl, pyridyl, bipyridyl, pyrimidinyl, triazinyl, acridinel, pyridazinyl, quinolinyl, quinazolinyl, quinoxazinyl, phenothiazinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, pyrazinopyrazinyl, isoquinolinyl, indolyl, carbazole, N-arylcarbazole, N-heteroarylcarbazole, N-alkylcarbazole, benzoxazolyl, benzimidazolyl, benzothiazolyl, benzocarbazole, benzothiaphenyl, dibenzophenylthio, thienothiaphenyl, benzofuranyl, phenanthrolyl, isoxazolyl, thiadiazolyl, phenothiazolyl, phenothiazinyl, dibenzothiaryl, dibenzofuranyl, etc.

[0079] In the description, silyl groups include alkylsilyl groups and arylsilyl groups. Examples of silyl groups may include, but are not limited to, trimethylsilyl, triethylsilyl, tert-butyldimethylsilyl, propyldimethylsilyl, triphenylsilyl, diphenylsilyl, phenylsilyl, etc.

[0080] In the description, there is no specific limitation on the number of carbon atoms in the amino group, but it can be from 1 to 30. The amino group can include alkylamino and arylamino groups. Examples of amino groups include, but are not limited to, methylamino, dimethylamino, phenylamino, diphenylamino, naphthylamino, 9-methyl-anthraylamino, etc.

[0081] In the description, boron groups include alkylboron groups and arylboron groups. Examples of boron groups may include, but are not limited to, dimethylboron, diethylboron, tert-butylmethylboron, diphenylboron, phenylboron, etc.

[0082] In the description, the alkyl groups in alkylaryl, alkylboronyl, alkylsilyl, and alkylamine are the same as the examples of alkyl groups described above.

[0083] In the description, the aryl groups in arylboryl, arylsilyl, and arylamino are the same as the examples of aryl groups described above.

[0084] In the description, This refers to the binding site with adjacent atoms.

[0085] The emission layer EML in the organic electroluminescent device 10 of the embodiment may include a compound represented by Formula 1.

[0086]

[0087] In Equation 1, X1 and X2 can each be O or S independently. For example, X1 and X2 can both be O, X1 and X2 can both be S, or one of X1 and X2 can be O and the other can be S.

[0088] In Equation 1, L1 to L 11 At least one of them may be a substituent represented by formula 2-a or formula 2-b. For example, in formula 1, it is selected from L1 to L 11 One of them, selected from L1 to L 11 Two of them or selected from L1 to L 11 The three in can be substituents represented by formula 2-a or formula 2-b.

[0089] Among them, L1 to L 11 In the case where one of them is a substituent represented by formula 2-a or formula 2-b, L1 to L 11 The remaining part may be, independently, a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted silyl group, a substituted or unsubstituted boron group, a substituted or unsubstituted straight-chain or branched 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.

[0090] For example, in Equation 1, where L1 to L 11 In the case where one of them is a substituent represented by formula 2-a or formula 2-b, L1 to L 11 The remaining portions may each independently be hydrogen atoms, deuterium atoms, fluorine atoms, cyano groups, arylamino groups, arylsilyl groups, arylboryl groups, straight-chain alkyl groups, branched-chain alkyl groups, unsubstituted aryl groups, aryl groups substituted with deuterium atoms, or unsubstituted heteroaryl groups. However, the embodiments are not limited thereto. L1 to L1 may be excluded. 11 In the case of cycloalkyl groups.

[0091] In the compounds represented by Formula 1 in the embodiments, L1 to L 11 At least one of them can be represented by equation 2-a or equation 2-b:

[0092]

[0093]

[0094] In equations 2-a and 2-b, R1 to R 24Each of these can independently be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted silyl group, a substituted or unsubstituted boryl 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. For example, in formulas 2-a and 2-b, R1 to R 24 Each of these atoms can be independently a hydrogen atom, a deuterium atom, a fluorine atom, a cyano group, an arylamino group, an arylsilyl group, an arylboryl group, a straight-chain alkyl group, a branched-chain alkyl group, an unsubstituted aryl group, an aryl group substituted with a deuterium atom, or an unsubstituted heteroaryl group, etc. However, the implementation methods are not limited to these.

[0095] In Formula 2-a, Ar1 and Ar2 may each be independently 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. For example, Ar1 and Ar2 may each be independently an unsubstituted phenyl group, a deuterium-substituted phenyl group, an unsubstituted biphenyl group, an unsubstituted naphthyl group, or an unsubstituted dibenzothiophene group. Ar1 and Ar2 may be the same as or different from each other. However, the implementation is not limited thereto.

[0096] In Formula 2-b, Ar3 is 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, a substituted or unsubstituted heteroaryl group having 2 to 30 cyclic carbon atoms, or a substituent represented by Formula 1.

[0097] In Equation 2-b, when Ar3 is a substituent represented by Equation 1 above, L1 to L3 in Ar3 may be excluded. 11 This refers to the case of a nitrogen-silane heterocyclohexane unit represented by formula 2-a or formula 2-b. For example, in formula 2-b, when Ar3 is a substituent represented by formula 1 above, L1 to L... 11 Each of these groups can independently be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted silyl group, a substituted or unsubstituted boryl group, a substituted or unsubstituted straight-chain or branched 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. In Formula 2-b, Ar3 can be a substituted or unsubstituted phenyl group. For example, Ar3 can be a substituent represented by Formula 1 above, or an unsubstituted phenyl group.

[0098] In the compounds of the embodiments, at least one hydrogen atom may be substituted with a deuterium atom. For example, all hydrogen atoms in the compounds of the embodiments may be substituted with deuterium atoms. For example, all other hydrogen atoms may be substituted with deuterium atoms except for the substituents represented by Formula 2-a or Formula 2-b in the compounds of the embodiments represented by Formula 1. For example, all hydrogen atoms in the substituents represented by Formula 2-a or Formula 2-b bonded to Formula 1 may be substituted with deuterium atoms.

[0099] The compounds represented by Formula 1 in the embodiments may be represented by one of Formulas 1-1 to 1-3. Formulas 1-1 to 1-3 represent examples of combinations of heteroatoms contained in the fused ring unit. For example, as represented by the following Formulas 1-1 to 1-3, the compounds in the embodiments may include fused ring units containing oxaborine or thiaborine:

[0100]

[0101] In equations 1-1 to 1-3, L1 to L 11 It can be the same as that specified in Equation 1.

[0102] The compounds in the embodiments may include fused ring units containing oxonium boron or thionium boron as electron acceptors.

[0103] The compound represented by Formula 1 in the embodiments can be represented by one of Formulas 1A to 1E. In Formulas 1A to 1E, DU can be represented by Formula 2-a or Formula 2-b as described above. Formulas 1A to 1E show embodiments based on the bonding sites of the nitrosilane units represented by DU and the number of bonded nitrosilane units.

[0104]

[0105] In Equations 1A to 1E, a to c can each be an integer selected from 0 to 3 independently. In Equations 1A to 1E, X1 and X2 can be the same as those defined in Equation 1. In Equations 1A to 1E, L a To L c and L1 to L 11 Each of the following can independently be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted silyl group, a substituted or unsubstituted boryl group, a substituted or unsubstituted straight-chain or branched 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. In the compounds represented by formulas 1A to 1E in the embodiments, L is not included. a To L c and L1 to L 11The cases represented by Equation 2-a or Equation 2-b.

[0106] For example, in the compounds represented by formulas 1A to 1E in the embodiments, L a To L c and L1 to L 11 Each of them can be independently a hydrogen atom, a deuterium atom, a fluorine atom, a cyano group, an arylamino group, an arylsilyl group, an arylboryl group, a straight-chain alkyl group, a branched-chain alkyl group, an unsubstituted aryl group, an aryl group substituted with a deuterium atom, or an unsubstituted heteroaryl group, etc.

[0107] The compound represented by Formula 1 in the embodiments can be represented by Formula 1F:

[0108]

[0109] In Equation 1F, R9 to R 24 As defined in Formula 2-b, AU is a substituent represented by Formula 1, but does not include cases where AU is substituted by a substituent represented by Formula 2-a or Formula 2-b above. For example, AU is not substituted by a substituent represented by Formula 2-a or Formula 2-b. For example, in the compound represented by Formula 1F of the embodiments, R9 to R 24 Each of these atoms can be independently a hydrogen atom, a deuterium atom, a fluorine atom, a cyano group, an arylamino group, an arylsilyl group, an arylboryl group, a straight-chain alkyl group, a branched-chain alkyl group, an unsubstituted aryl group, an aryl group substituted with a deuterium atom, or an unsubstituted heteroaryl group, etc. However, the implementation methods are not limited to these.

[0110] Formula 1F illustrates an embodiment having a structure containing a nitrosilane heterocyclohexane unit represented by Formula 2-b and a fused ring unit represented by Formula 1. The compound represented by Formula 1F in the embodiment may have a structure containing two electron acceptor units, which may be represented by Formula 1, and one electron donor unit, which may be represented by Formula 2-b.

[0111] The compounds represented by Formula 1 in the embodiments can be represented by one of Formulas 1F-1 to 1F-3. Formulas 1F-1 to 1F-3 show embodiments having a structure containing a nitrosilane heterocyclohexane unit represented by Formula 2-b and a fused ring unit represented by Formula 1. Formulas 1F-1 to 1F-3 show embodiments with different fused ring unit bonding sites bonded to the nitrosilane heterocyclohexane unit.

[0112]

[0113]

[0114] In equations 1F-1 to 1F-3, L1 to L 11Each of these can independently be a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted silyl group, a substituted or unsubstituted boryl group, a substituted or unsubstituted straight-chain or branched 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. In Formulas 1F-1 to 1F-3, X1 and X2 can be the same as those defined in Formula 1, and R9 to R 24 It can be the same as that defined in Equation 2-b.

[0115] The compounds described above have a molecular structure in which a fused ring unit containing boron atoms is bonded to a nitrogen-silicon heterocyclohexane unit, and therefore the charge separation state in the molecule can be maintained at a suitable level to promote inter-antral crossing. Thus, the compounds of the embodiments can have a small ΔE. ST The value is used to demonstrate improved fluorescence efficiency. For example, if the compound according to the embodiment is used as the emission layer material of the organic electroluminescent device 10, the light emission efficiency characteristics of the organic electroluminescent device 10 can be improved.

[0116] The compounds of the embodiments have a molecular structure in which anti-intersystem crossing readily occurs by bonding at least one electron acceptor and at least one electron donor, and are thus usable as thermally activated delayed fluorescence (TADF) materials. For example, the compounds of the embodiments can be used as TADF dopant materials that emit blue light. The compounds of the embodiments represented by Formula 1 may have a central emission wavelength (λ) in a wavelength region less than or equal to about 490 nm. max The luminescent material is a material that emits light. For example, the compound represented by Formula 1 in the embodiments can be a luminescent material having a central emission wavelength in the wavelength region ranging from about 430 nm to about 490 nm. The compound represented by Formula 1 in the embodiments can be a blue thermally activated delayed fluorescence dopant. For example, the compound in the embodiments can be used as a TADF material that emits deep blue light.

[0117] The compounds used in the embodiments may be selected from one of the compounds represented by compound group 1, including compounds 1 to 234. The organic electroluminescent device 10 of the embodiments may include at least one compound represented by compound group 1 in the emitting layer EML. In the compounds represented by compound group 1, "Ph" represents phenyl.

[0118] [Compound Group 1]

[0119]

[0120]

[0121]

[0122]

[0123]

[0124]

[0125]

[0126]

[0127]

[0128]

[0129]

[0130]

[0131]

[0132]

[0133]

[0134]

[0135]

[0136]

[0137]

[0138]

[0139] Although not all embodiments are listed, at least one hydrogen atom in the compounds of the embodiments may be replaced by a deuterium atom. For example, any hydrogen atom in the compounds according to the embodiments may be replaced by a deuterium atom.

[0140] For example, the compounds of the embodiments may have the same form as compounds 1-d, corresponding to the form in which hydrogen atoms in compound 1 of compound group 1 are replaced by deuterium atoms, and although not listed, any form in which hydrogen atoms are replaced by deuterium atoms may be equivalently provided to the compounds of other embodiments described in compound group 1.

[0141] The emitting layer EML in the organic electroluminescent device 10, which includes the compounds of the embodiments, can emit delayed fluorescence. For example, the emitting layer EML can emit thermally activated delayed fluorescence (TADF).

[0142] Although not shown in the accompanying drawings, the organic electroluminescent device 10 of the embodiments may include multiple emission layers. Multiple emission layers may be stacked and provided sequentially. 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 10 having a series structure. When the organic electroluminescent device 10 includes multiple emission layers, at least one emission layer EML may include the compound of the embodiments described above.

[0143] In embodiments, the emission layer EML may include a host and a dopant, and may include compounds from the above embodiments as dopant. For example, the emission layer EML in the organic electroluminescent device 10 of the embodiments may include a host for emitting delayed fluorescence and a dopant for emitting delayed fluorescence, and may include compounds from the above embodiments as dopant for emitting delayed fluorescence. The emission layer EML may include at least one of the compounds represented by compound group 1 as a thermally activated delayed fluorescence dopant.

[0144] In embodiments, the emission layer EML may be a delayed fluorescence emission layer, and the emission layer EML may include a known host material and the aforementioned compounds. For example, in the organic electroluminescent device 10 of the embodiments, the compounds of the embodiments may be used as TADF dopants.

[0145] In embodiments, the emitter layer EML may include known host materials. For example, 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(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene (TPBi), 3-tert-butyl-9,10-bis(naphthyl-2-yl)anthracene (TBADN), stilbene aromatics (DSA), and 4,4'-bis(9-carbazolyl)-2,2'-dimethyl-biphenyl (CDBP) as host materials. Examples of suitable host materials include 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)dibenzo[b,d]furan (PPF), 3,3'-bis(N-carbazolyl)-1,1'-biphenyl (mCBP), and 1,3-bis(N-carbazolyl)benzene (mCP). However, embodiments are not limited to these and may include known delayed fluorescence emission host materials other than those listed.

[0146] The emission layer EML in the organic electroluminescent device 10 of the embodiment may further include known dopant materials. In the embodiment, the emission layer EML may further include styrene derivatives (e.g., 1,4-bis[2-(3-N-ethylcarbazolyl)vinyl]benzene (BCzVB), 4-(di-p-tolylamino)-4'-[(di-p-tolylamino)styrene]stilbene (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-tetratert-butylperylene (TBP)), pyrene and its derivatives (e.g., 1,1'-dipyrene, 1,4-dipyrenebenzene, 1,4-bis(N,N-diphenylamino)pyrene), etc.) as dopant materials.

[0147] exist Figures 1 to 4In the organic electroluminescent device 10 of the illustrated embodiment, an electron transport region (ETR) is provided on the emitter layer (EML). The ETR may include at least one of a hole blocking layer (HBL), an electron transport layer (ETL), and an electron injection layer (EIL), but the embodiment is not limited thereto. The ETR may have a single layer formed of a single material, a single layer formed of different materials, or a multilayer structure including layers formed of different materials.

[0148] For example, the electron transport region (ETR) may have a single-layer structure of an electron injection layer (EIL) or an electron transport layer (ETL), and may have a single-layer structure formed of an electron injection material and an electron transport material. The ETR may have a single-layer structure formed of different materials, or may have a structure in which the electron transport layer (ETL) / electron injection layer (EIL) or hole blocking layer (HBL) / electron transport layer (ETL) / electron injection layer (EIL) are stacked sequentially from the emitter layer (EML), but is not limited thereto. The thickness of the ETR may, for example, be approximately [insert thickness here]. to approximately Within the range.

[0149] Electron transport regions (ETRs) can be formed using various methods, such as vacuum deposition, spin coating, casting, Langmuir-Brockett (LB) method, inkjet printing, laser printing, and laser-induced thermal imaging (LITI).

[0150] When the electron transport region (ETR) includes an electron transport layer (ETL), the ETL may include anthracene compounds. However, embodiments are not limited thereto, and the ETL 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 (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-quinolinyl-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum (BAlq), bis(benzoquinoline-10-hydroxy)beryllium (Bebq2), 9,10-bis(naphthyl-2-yl)anthracene (ADN), 1,3-bis[3,5-bis(pyridin-3-yl)phenyl]benzene (B3PyPB), or mixtures thereof. The thickness of the electron transport layer (ETL) can be approximately to approximately Within a certain range. For example, the thickness of the electron transport layer (ETL) can be approximately... to approximately Within the specified range. If the thickness of the electron transport layer (ETL) meets the above range, satisfactory electron transport characteristics can be obtained without significantly increasing the driving voltage.

[0151] When the electron transport region (ETR) includes an electron injection layer (EIL), the EIL can be formed using metal halides such as LiF, NaCl, CsF, RbCl, RbI, and CuI, lanthanides such as Yb, co-depositions of metal halides and lanthanides (e.g., KI:Yb or RbI:Yb), metal oxides such as Li₂O and BaO, lithium 8-hydroxyquinoline (LiQ), etc., but the implementation is not limited to these. The EIL can also be formed from a mixture of an electron injection material and an insulating organometallic salt. The insulating organometallic salt can be a material having a band gap greater than or equal to about 4 eV. For example, the insulating organometallic salt may include metal acetates, metal benzoates, metal acetoacetates, metal acetylacetonates, or metal stearates. The thickness of the EIL can be approximately... to approximately Within a certain range. For example, the thickness of the electron-injected layer (EIL) can be approximately... to approximately Within the specified range. If the thickness of the electron injection layer (EIL) meets the above range, satisfactory electron injection characteristics can be obtained without significantly increasing the driving voltage.

[0152] The electron transport region (ETR) may include a hole blocking layer (HBL) as described above. The hole blocking layer (HBL) may include, for example, at least one of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline (Bphen), DPEPO, and PPF, but is not limited thereto.

[0153] The second electrode EL2 is provided on the electron transport region ETR. The second electrode EL2 can be a common electrode or a cathode. 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 include a transparent metal oxide, such as ITO, IZO, ZnO, ITZO, etc.

[0154] When the second electrode EL2 is a transmissive or reflective electrode, the second electrode EL2 may include at least one material selected from the group consisting of: Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF, Mo, Ti, Yb, compounds thereof, and mixtures thereof (e.g., a mixture of Ag and Mg or a mixture of Ag and Yb). In other embodiments, the second electrode EL2 may have a multilayer structure, the multilayer structure including a reflective or transmissive layer formed of the above materials, and a transparent conductive layer formed of ITO, IZO, ZnO, ITZO, etc.

[0155] Although not shown, the second electrode EL2 can be connected to the auxiliary electrode. If the second electrode EL2 is connected to the auxiliary electrode, the resistance of the second electrode EL2 can decrease.

[0156] The capping layer CPL may be further disposed on the second electrode EL2 of the organic electroluminescent device 10 according to the embodiment. The refractive index of the capping layer CPL may be greater than or equal to about 1.6. For example, the refractive index of the capping layer CPL may be greater than or equal to about 1.6 at a wavelength of about 589 nm.

[0157] The capping layer CPL can be an organic layer or an inorganic layer. For example, when the capping layer CPL includes inorganic materials, the inorganic materials may include alkali metal compounds such as LiF, and alkaline earth metal compounds such as MgF2, SiON, and SiN. x SiO y wait.

[0158] For example, when the capping layer CPL comprises an organic material, the organic material may include 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), epoxy resin, or acrylate such as methacrylate. However, the embodiments are not limited thereto, and the organic material may also include compounds P1 to P5 listed below.

[0159]

[0160]

[0161] However, the implementation is not limited to this, and the capping layer CPL may include an amine compound. For example, the capping layer CPL may include at least one of the following compounds: CPL1 and CPL2:

[0162]

[0163] The organic electroluminescent device 10 according to an embodiment of the present invention may include the compound described above in the emitter layer EML disposed between the first electrode EL1 and the second electrode EL2 to exhibit excellent light emission efficiency. The organic electroluminescent device 10 of the embodiment can exhibit high light emission efficiency in the blue light emission wavelength region. The compound according to the embodiment may be a thermally activated delayed fluorescence dopant, and the emitter layer EML may include the compound of the embodiment to emit thermally activated delayed fluorescence, thereby exhibiting good light emission efficiency characteristics.

[0164] In addition to the emitting layer EML, the compounds described in the above embodiments can be included in the functional layers as materials for the organic electroluminescent device 10. For example, the organic electroluminescent device 10 of the present invention may also include the above compounds in at least one functional layer disposed between the first electrode EL1 and the second electrode EL2, or in the capping layer CPL disposed on the second electrode EL2.

[0165] When the compounds of the above embodiments are used as materials for the organic electroluminescent device 10 by means of fused ring units comprising a nitrosilane heterocyclohexane unit and an oxane-boron or thionane-boron ring containing a boron atom (B), the efficiency of the organic electroluminescent device 10 can be further improved. Furthermore, the organic electroluminescent device 10 of the embodiments comprising the compounds of the embodiments in the emitting layer can emit deep blue light and exhibits high efficiency.

[0166] In the following, with reference to embodiments and comparative examples, compounds and organic electroluminescent devices 10 according to embodiments of the present invention will be described in detail. The embodiments shown below are provided only for understanding the inventive concept, and the scope of the inventive concept is not limited thereto.

[0167] [Example]

[0168] 1. Synthesis of a compound according to one embodiment

[0169] First, the synthesis methods of the compounds according to the embodiments will be described in detail by explaining the synthesis methods of compounds 1, 55, and 60. In the following description, the compound synthesis methods are provided as examples, but the synthesis methods of the compounds according to embodiments of the present invention are not limited to the examples below.

[0170] (1) Synthesis of Compound 1

[0171] Compound 1 according to the embodiments can be synthesized by, for example, the steps shown in reaction scheme 1 below:

[0172] [Reaction Scheme 1]

[0173]

[0174] Under a nitrogen atmosphere, intermediates A-1 (0.70 g, 2.00 mmol), A-2 (0.49 g, 1.40 mmol), Pd2(dba)3 (0.09 g, 0.10 mmol), SPhos (2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl) (0.04 g, 0.10 mmol), and t-BuONa (sodium tert-butoxide) (0.19 g, 2.00 mmol) were refluxed in toluene for 3 hours. The reaction mixture was cooled to room temperature and filtered using a diatomaceous earth pad. The filtrate was concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (using an eluent of hexane and chloroform in a 2:1 volume ratio) to give compound 1 (0.25 g, 20% yield) as a white solid. Compound 1 was identified by NMR analysis. 1 H NMR (500MHz, CDCl3, δ): 8.72 (d, J=7.5Hz, 2H), 7.72 (d, J=7.5Hz, 2H), 7.64-7.61 (m, 6H), 7.52 (d, J=8.5H z, 2H), 7.43-7.36 (m, 8H), 7.26-7.21 (m, 2H), 7.11 (s, 2H), 7.01 (t, J=7.3Hz, 2H), 6.75 (d, J=8.5Hz, 2H)]

[0175] (2) Synthesis of compound 55

[0176] Compound 55 according to the embodiments can be synthesized, for example, by the steps shown in reaction scheme 2 below:

[0177] [Reaction Scheme 2]

[0178]

[0179] Under a nitrogen atmosphere, intermediates B-1 (0.51 g, 2.00 mmol), A-2 (0.81 g, 2.32 mmol), Pd2(dba)3 (0.10 g, 0.10 mmol), SPhos (0.04 g, 0.10 mmol), and t-BuONa (0.32 g, 2.00 mmol) were refluxed in toluene for 3 hours. The reaction mixture was cooled to room temperature and filtered using a diatomaceous earth pad. The filtrate was concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (using an eluent of hexane and chloroform in a 2:1 volume ratio) to give compound 55 (0.14 g, 14% yield) as a pale yellow solid. Compound 55 was identified by NMR analysis. 1 H NMR (500MHz, CDCl3, δ): 8.86 (d, J=8.0Hz, 2H), 7.82 (t, J=8.3Hz, 1H), 7.65-7.62 (m, 12H), 7.48 (s, 2H), 7.4 3-7.37 (m, 12H), 7.29 (d, J = 8.5Hz, 2H), 7.23 (t, J = 7.0Hz, 6H), 7.01 (t, J = 7.3Hz, 4H), 6.72 (d, J = 8.5Hz, 4H)]

[0180] (3) Synthesis of compound 60

[0181] Compound 60 according to the embodiments can be synthesized, for example, by the steps shown in reaction scheme 3 below:

[0182] [Reaction Scheme 3]

[0183]

[0184] Under a nitrogen atmosphere, intermediates B-1 (0.51 g, 2.00 mmol), B-2 (0.88 g, 2.32 mmol), Pd2(dba)3 (0.10 g, 0.10 mmol), SPhos (0.04 g, 0.10 mmol), and t-BuONa (0.32 g, 2.00 mmol) were refluxed in toluene for 3 hours. The reaction mixture was cooled to room temperature and filtered using a diatomaceous earth pad. The filtrate was concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (using an eluent of hexane and chloroform in a 2:1 volume ratio) to give compound 60 (0.12 g, 11% yield) as a pale yellow solid. Compound 60 was identified by NMR analysis. 1 H NMR (500MHz, CDCl3, δ): 8.74 (d, J=8.4Hz, 2H), 7.80 (t, J=8.2Hz, 1H), 7.65 (dd, J=7.6, 1.6Hz, 8H), 7.4 3-7.88 (m, 18H), 7.23-7.19 (m, 4H), 7.09 (dd, J=8.8, 2.0Hz, 4H), 6.74 (d, J=8.4Hz, 4H), 2.29 (s, 12H)]

[0185] 2. Evaluation of compound characteristics

[0186] The results of quantum chemical calculations for the example and comparative example compounds are shown below. For the example and comparative example compounds, the structure of B3LYP / 6-31G(d) was optimized using Gaussian09 Rev.D.01, and a TD-DFT of B3LYP / 6-31G(d) was performed to obtain the lowest singlet exciton level (S1) and the lowest triplet exciton level (T1). The obtained lowest singlet exciton level (S1) and lowest triplet exciton level (T1) are listed for comparison. The difference between S1 and T1 is expressed as ΔE. ST .

[0187] The compounds used in the examples and comparative examples used for evaluation are listed in Table 1 below:

[0188] [Table 1]

[0189]

[0190]

[0191] The results of quantum chemical calculations for the compounds in the examples and comparative examples are listed in Table 2.

[0192] [Table 2]

[0193]

[0194]

[0195] Referring to the results in Table 2, it can be confirmed that the compounds in the examples show a ΔE of 0.01 or less. ST Therefore, it can be confirmed that the compound of the examples has a small ΔE value. ST The compound exhibits a low ΔE value and can therefore be used as a thermally activated delayed fluorescence dopant. It is believed that the compound in the examples has a smaller ΔE value compared to the compound in the comparative examples. ST The values ​​are higher, and therefore the compounds in the examples exhibit improved light emission efficiency compared to the comparative example compounds.

[0196] 3. Evaluation of the fluorescence characteristics of the compound

[0197] Photoluminescence quantum yield (PLQY) was evaluated for the example and comparative example compounds. Samples for evaluating fluorescence characteristics were prepared by depositing compositions comprising the example and comparative example compounds used for evaluation onto a quartz substrate to form an organic film. The evaluation of the prepared samples was conducted in an inert gas atmosphere. In the preparation of the samples, DPEPO or PPF was used as the host material. The prepared sample compositions contained 12 wt% to 50 wt% of the example or comparative example compounds based on the total weight of the composition.

[0198] Fluorescence emission characteristics were evaluated by measuring fluorescence emission spectra using a JASCO V-670 spectrometer. Photoluminescence quantum yields were determined using the same samples via a JASCO ILF-835 integrating sphere system. The results of the evaluation of the fluorescence characteristics of the example and comparative example compounds are listed in Table 3.

[0199] [Table 3]

[0200] 1 451 81 1.9 55 465 98 2.3 60 484 99 1.6 C1 439 68 6.0 C2 453 75 4.5 C3 492 92 2.6

[0201] “PLλ max "(nm)" means "maximum wavelength" and "Tau delay / μsec" means "delay time".

[0202] Referring to the results in Table 3, it can be confirmed that the compounds of the examples emit deep blue light with a maximum emission wavelength of less than or equal to about 490 nm. It can also be confirmed that the compounds of the examples exhibit fluorescence efficiency of 80% or higher, demonstrating good light emission efficiency characteristics. Compared with the comparative example compounds, the compounds of the examples exhibit a smaller retardation time (Tau retardation), and therefore it can be predicted that the delayed fluorescence efficiency of the compounds of the examples is higher than that of the comparative example compounds.

[0203] 4. Manufacturing and evaluation of organic electroluminescent devices

[0204] The following is an evaluation of an organic electroluminescent device comprising the compound of the embodiment in the emitting layer. A method for manufacturing the organic electroluminescent device for device evaluation is described below.

[0205] Organic electroluminescent devices of Examples 1 to 3 were fabricated by using compounds 1, 55, and 60 as dopant materials for the emission layer. Comparative Examples 1 and 2 are organic electroluminescent devices fabricated by using each of Comparative Example Compound C1 and Comparative Example Compound C2 as dopant materials for the emission layer.

[0206] (Manufacturing of organic electroluminescent devices)

[0207] The organic electroluminescent devices of the following manufacturing embodiments and comparative examples are described. ITO is patterned on a glass substrate to form a first electrode. HAT-CN is deposited onto approximately... The thickness is such that a hole injection layer is formed, and TAPC is deposited to approximately [a certain thickness]. The thickness is used to form a hole transport layer, and mDCP is used to form it. A thick electron-blocking layer. In the formation of the emission layer, the example compound and PPF are co-deposited in a ratio of approximately 20:80 to form... Thick layers. For example, an emission layer formed by co-deposition is deposited by mixing the example compound and PPF.

[0208] Forming on the emitter layer using PPF Thick layers, formed using B3PyPB Thick layers, formed with LiF A thick layer is formed to create the electron transport region. A layer of approximately [thickness missing] is formed using aluminum (Al). The second electrode.

[0209] The compounds used to manufacture each functional layer of the organic electroluminescent device are as follows.

[0210]

[0211] (Evaluation of the characteristics of organic electroluminescent devices)

[0212] The evaluation results of the organic electroluminescent devices of the examples and comparative examples are listed in Table 4. The maximum emission wavelength (λ) of the manufactured organic electroluminescent devices... max The external quantum efficiency (ηext) and the maximum emission wavelength (λ) are listed in Table 4 for comparison. In the evaluation results of the characteristics of the embodiments and comparative examples, the maximum emission wavelength (λ) is... max () indicates the wavelength that displays the maximum value in the emission spectrum.

[0213] [Table 4]

[0214]

[0215] Referring to the results in Table 4, it can be confirmed that the organic electroluminescent devices of the embodiments emit light in the blue wavelength region less than or equal to about 480 nm, thus exhibiting high light emission efficiency. It can be confirmed that Examples 1 to 3 exhibit higher external quantum efficiency values ​​compared to the comparative examples.

[0216] The compounds of the embodiments may include at least one fused-ring unit containing boron atoms and at least one nitrosilane unit bonded to the fused-ring unit to promote anti-system crossing, thereby exhibiting excellent light emission efficiency. The organic electroluminescent devices of the embodiments may include the compounds of the embodiments in the emitting layer to exhibit high light emission efficiency in the deep blue emission wavelength region.

[0217] The organic electroluminescent device described in this embodiment can exhibit excellent light emission efficiency.

[0218] The compounds of the embodiments may be included in the emitting layer of the organic electroluminescent device to contribute to the high efficiency of the organic electroluminescent device.

[0219] Although the inventive concept has been described with reference to embodiments thereof, it should be understood that the inventive concept is not limited to these embodiments, but that various changes and modifications can be made by those skilled in the art without departing from the spirit and scope of the inventive concept.

[0220] Therefore, the technical scope of the present invention is not intended to be limited to the contents set forth in the detailed description of the specification, but is intended to be defined by the claims.

Claims

1. An organic electroluminescent device, the organic electroluminescent device comprising: First electrode; A second electrode disposed on the first electrode; as well as An emission layer disposed between the first electrode and the second electrode. The emission layer comprises a compound represented by Formula 1: [Formula 1] In Equation 1, X1 and X2 are each independently O or S. L1 to L 11 At least one of them is a substituent represented by formula 2-a, and L1 to L 11 The remaining portions are each independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, or a substituted or unsubstituted straight-chain or branched alkyl group having 1 to 20 carbon atoms: [Equation 2-a] In equation 2-a, R1 to R8 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms. Ar1 and Ar2 are each independently substituted or unsubstituted aryl groups having 6 to 30 cyclic carbon atoms. This refers to the binding site with adjacent atoms, and The term "substituted or unsubstituted" indicates that the substance is either unsubstituted or substituted by at least one substituent selected from the group consisting of: deuterium, halogen, cyano, nitro, amino, and alkyl having 1 to 20 carbon atoms.

2. The organic electroluminescent device according to claim 1, wherein formula 1 is represented by one of formulas 1-1 to 1-3: [Equation 1-1] [Equation 1-2] [Equation 1-3] Among them, in equations 1-1 to 1-3, L1 to L 11 Same as that defined in Equation 1.

3. The organic electroluminescent device according to claim 1, Equation 1 is represented by one of Equations 1A to 1E: [Equation 1A] [Equation 1B] [Equation 1C] [Equation 1D] [Formula 1E] Among them, in equations 1A to 1E, a to c are each an independent integer selected from 0 to 3. X1 and X2 are the same as those defined in Equation 1. L a To L c and L1 to L 11 Each is independently a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, or a substituted or unsubstituted straight-chain or branched alkyl group having 1 to 20 carbon atoms, and DU is represented by equation 2-a.

4. The organic electroluminescent device according to claim 1, wherein... Ar1 and Ar2 are each independently an unsubstituted phenyl, a phenyl substituted with a deuterium atom, an unsubstituted biphenyl, or an unsubstituted naphthyl.

5. The organic electroluminescent device according to claim 1, wherein... The organic electroluminescent device further includes a capping layer disposed on the second electrode, and The capping layer has a refractive index greater than or equal to 1.

6.

6. The organic electroluminescent device according to claim 1, wherein... The emission layer is a delayed fluorescence emission layer containing a host and dopants, and The dopant includes the compound represented by Formula 1.

7. The organic electroluminescent device according to claim 1, wherein the emitting layer emits light having a center wavelength in the range of 430 nm to 490 nm.

8. The organic electroluminescent device according to claim 1, wherein the emitting layer comprises at least one of the compounds represented by group 1: [Compound Group 1] 。

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