Organic electroluminescent element

Abstract

The purpose of the present invention is to provide an organic electroluminescent element which has excellent driving voltage characteristics and current efficiency characteristics, while having little change in efficiency and change in efficiency after continuous driving. This organic electroluminescent element is provided with: an anode; a cathode; the anode is opposite to the anode; a light-emitting layer disposed between the anode and the cathode; the organic electroluminescent element includes an anode, a light-emitting layer disposed between the anode and the light-emitting layer, a hole transport region disposed between the anode and the light-emitting layer, and an electron transport region disposed between the light-emitting layer and a cathode, the electron transport region containing a triazine compound represented by formula (2), the organic electroluminescent element satisfying at least one of the following conditions (i) and (ii). # imgabs0 # (i) The light-emitting layer contains a boron compound represented by formula (1). # imgabs1 # (ii) the hole transport region contains an axiene compound represented by formula (3). # imgabs2 #

Description

Technical Field

[0001] The present invention relates to an organic electroluminescent element. Background Art

[0002] Organic electroluminescent elements can capture light of any wavelength by using appropriate luminescent materials. Due to their usefulness, they are being actively developed for applications such as not only small display devices but also lighting. In any application, any color tone can be expressed by combining red, green, and blue light with appropriate intensities.

[0003] Conventionally, it has been desired that an organic electroluminescent element be driven at a low voltage and emit light with high efficiency, and organic electroluminescent elements have been disclosed in recent years.

[0004] Conventionally, it has been desired that organic electroluminescent elements be driven at a low voltage and emit light at a high efficiency, and in recent years, materials for organic electroluminescent elements have been gradually improved.

[0005] For example, Patent Documents 1 and 2 disclose organic electroluminescent elements having low driving voltage, high efficiency and long life. Prior art literature Patent Literature

[0006] Patent Document 1: International Publication No. 2020 / 117026 Patent Document 2: Japanese Patent Application Laid-Open No. 2020-033264 Summary of the invention Technical problem to be solved by the invention

[0007] However, in recent years, the market has increasingly higher requirements for organic electroluminescent elements, requiring not only the development of organic electroluminescent elements with excellent driving voltage characteristics and current efficiency characteristics, but also the development of organic electroluminescent elements capable of precise control of color tone. Moreover, in order to be able to perform subtle adjustments and controls on the color tone, it is expected that the efficiency is also high in a wide range from low brightness to high brightness, and the change in efficiency is small (hereinafter, the change in efficiency is also referred to as "efficiency change"). In addition, in order to be able to perform subtle adjustments and controls on the color tone, it is expected that the efficiency does not change before and after the element is continuously driven (hereinafter, the change in efficiency is also referred to as "efficiency change after continuous driving"). One embodiment of the present invention is to provide an organic electroluminescent element having excellent driving voltage characteristics and current efficiency characteristics, and having small efficiency changes and efficiency changes after continuous driving. Technical solutions for solving technical problems

[0008] According to one embodiment of the present invention, an organic electroluminescent element comprises: [1] anode; a cathode, which is opposite to the anode; A light-emitting layer disposed between the anode and the cathode; a hole transport region disposed between the anode and the light-emitting layer; and An electron transport region, which is disposed between the light-emitting layer and the cathode; The electron transport region contains a triazine compound represented by formula (2), The organic electroluminescent element satisfies at least one of the following conditions (i) and (ii).

[0009] (i) The light-emitting layer contains a boron compound represented by formula (1).

[0010] (ii) The hole transport region contains a radialene compound represented by formula (3).

[0011] [Chemistry 1]

[0012] In formula (2), Ar 1 represents a phenyl group which may be substituted with an alkyl group having 1 to 6 carbon atoms, a naphthyl group which may be substituted with an alkyl group having 1 to 6 carbon atoms, or a biphenyl group which may be substituted with an alkyl group having 1 to 6 carbon atoms, Ar 2 It represents a phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, a pyridyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, a phenylpyridyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, a pyridylphenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, or a biphenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms. Ar 3 It represents a phenyl group or a biphenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms.

[0013] [Chemistry 2]

[0014] In formula (1), ring A, ring B and ring C each independently represent: an aromatic hydrocarbon ring having 6 to 20 ring atoms which may have a substituent, or an aromatic heterocyclic ring having 5 to 20 ring atoms which may have a substituent; Ra, Rb, and Rc each independently represent deuterium, cyano, an alkyl group having 1 to 20 carbon atoms, an amino group which may be substituted, an aromatic hydrocarbon group having 6 to 20 ring atoms, or a heteroaromatic group having 5 to 20 ring atoms. a, b, and c are each independently an integer of 0 to 4, Ring A and ring B may be linked via an oxygen atom, a sulfur atom, N-R', Ra or Rb. R1 , R 2 , R' each independently represents: an alkyl group having 1 to 20 carbon atoms which may have a substituent, an aromatic hydrocarbon group having 6 to 20 ring atoms which may have a substituent, or a heteroaromatic group having 5 to 20 ring atoms which may have a substituent; R 1 It may be linked to ring A or ring C via an oxygen atom, a sulfur atom, a nitrogen atom which may be substituted, Ra or Rc to form a ring structure, R 2 It may be linked to ring B or ring C via an oxygen atom, a sulfur atom, a nitrogen atom which may be substituted, Rb or Rc to form a ring structure.

[0015] [Chemistry 3]

[0016] In formula (3), R 3 Each independently represents a cyano group, a halogen atom, a fluoroalkyl group, an acyl group, a sulfonyl group, a phosphoryl group, an optionally substituted aromatic hydrocarbon group, or an optionally substituted aromatic heterocyclic group. [2] The organic electroluminescent element according to [1], wherein the organic electroluminescent element satisfies the condition (i) of (i) and (ii). [3] The organic electroluminescent element according to [1], wherein the organic electroluminescent element satisfies the condition (ii) among (i) and (ii). [4] The organic electroluminescent element according to [1], wherein the organic electroluminescent element satisfies both conditions (i) and (ii) above. [5] The organic electroluminescent device according to [2] or [4], wherein in the formula (1), at least one of the rings A to C is a benzene ring which may have a substituent. [6] The organic electroluminescent device according to [2], [4] or [5], wherein in the formula (1), rings A to C are rings containing a benzene structure which may have a substituent. [7] The organic electroluminescent device according to [2], [4], [5] or [6], wherein in formula (1), at least one of Ra, Rb and Rc is an alkyl group having 1 to 4 carbon atoms. [8] The organic electroluminescent device according to [2], [4], [5], [6] or [7], wherein the boron compound represented by formula (1) is selected from the following compounds.

[0017] [Chemistry 4] [9] The organic electroluminescent device according to [2], [4], [5], [6], [7] or [8], wherein the boron compound represented by formula (1) is the compound 1-1.

[10] The organic electroluminescent element according to [3] or [4], wherein the hole transport region has at least: a first hole transport layer; and The second hole transport layer is disposed between the first hole transport layer and the light emitting layer. The first hole transport layer contains a radialene compound represented by formula (3).

[11] The organic electroluminescent device according to [3], [4] or

[10] , wherein the radialene compound represented by formula (3) is formula (3-a).

[0019] [Chemistry 5]

[0020] In formula (3-a), R 3 Each independently represents a cyano group, a halogen atom, a fluoroalkyl group, an acyl group, a sulfonyl group, a phosphoryl group, an optionally substituted aromatic hydrocarbon group, or an optionally substituted aromatic heterocyclic group.

[0021] Ar 4 Each independently represents an aromatic hydrocarbon group which may be substituted, or an aromatic heterocyclic group which may be substituted.

[0022] R 3 and Ar 4 The substituents of the aromatic hydrocarbon group which may be substituted and the aromatic heterocyclic group which may be substituted are each independently selected from deuterium, a cyano group, a halogen atom, a fluoroalkyl group, an acyl group, a sulfonyl group, and a phosphoryl group.

[12] The organic electroluminescent device according to [3], [4],

[10] or

[11] , wherein the radialene compound represented by formula (3) is formula (3-b).

[0023] [Chemistry 6]

[0024] In formula (3-b), R 31 Each is independently selected from deuterium, a cyano group, a halogen atom, a fluoroalkyl group, an acyl group, a sulfonyl group, and a phosphoryl group.

[0025] s is an integer of 1-5 each independently.

[13] The organic electroluminescent device according to [3], [4],

[10] ,

[11] or

[12] , wherein the radialene compound represented by formula (3) is the following formula 3-1.

[0026] [Chemistry 7]

[14] The organic electroluminescent element according to any one of [1] to

[13] , wherein the electron transport region has at least: a first electron transport layer; and A second electron transport layer, which is disposed between the first electron transport layer and the cathode; The second electron transport layer contains a triazine compound represented by formula (2).

[15] The organic electroluminescent device according to any one of [1] to

[13] , wherein the triazine compound represented by formula (2) is the following compound.

[0028] [Chemistry 8]

[16] The organic electroluminescent device according to any one of [1] to

[15] , wherein the second electron transport layer contains a compound represented by formula (2) and lithium quinolate (Liq).

[0030] [Chemistry 9] Effects of the Invention

[0031] The organic electroluminescent element as one embodiment of the present invention can achieve both excellent driving voltage characteristics and current efficiency characteristics, and can reduce efficiency variation and efficiency variation after continuous driving, thereby realizing an element suitable for color tone reproduction in display devices and lighting devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic cross-sectional view showing an example of a stacked structure of an organic electroluminescent element according to one embodiment of the present invention. DETAILED DESCRIPTION

[0033] Hereinafter, an organic electroluminescent element according to one embodiment of the present invention will be described in detail. <Organic electroluminescent element> An organic electroluminescent device according to one embodiment of the present invention is an organic electroluminescent device as described below, comprising: anode; a cathode, which is opposite to the anode; A light-emitting layer disposed between the anode and the cathode; a hole transport region disposed between the anode and the light-emitting layer; and An electron transport region, which is disposed between the light-emitting layer and the cathode; The electron transport region contains a triazine compound represented by formula (2), The organic electroluminescent element satisfies at least one of the following conditions (i) and (ii).

[0034] (i) The light-emitting layer contains a boron compound represented by formula (1).

[0035] (ii) The hole transport region contains a radialene compound represented by formula (3).

[0036] [Chemistry 10]

[0037] In formula (2), Ar 1 represents a phenyl group which may be substituted with an alkyl group having 1 to 6 carbon atoms, a naphthyl group which may be substituted with an alkyl group having 1 to 6 carbon atoms, or a biphenyl group which may be substituted with an alkyl group having 1 to 6 carbon atoms, Ar 2 It represents a phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, a pyridyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, a phenylpyridyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, a pyridylphenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, or a biphenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms. Ar 3 It represents a phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, or a biphenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms.

[0038] [Chemistry 11]

[0039] In formula (1), ring A, ring B and ring C each independently represent: an aromatic hydrocarbon ring having 6 to 20 ring atoms which may have a substituent, or an aromatic heterocyclic ring having 5 to 20 ring atoms which may have a substituent; Ra, Rb, and Rc are each independently deuterium, cyano, an alkyl group having 1 to 20 carbon atoms, an amino group which may be substituted, an aromatic hydrocarbon group having 6 to 20 ring atoms, or a heteroaromatic group having 5 to 20 ring atoms; a, b, and c are each independently an integer of 0 to 4, Ring A and ring B may be linked via an oxygen atom, a sulfur atom, N-R', Ra or Rb. R 1 , R 2 , R' each independently represents: an alkyl group having 1 to 20 carbon atoms which may have a substituent, an aromatic hydrocarbon group having 6 to 20 ring atoms which may have a substituent, or a heteroaromatic group having 5 to 20 ring atoms which may have a substituent; R 1 It may be linked to ring A or ring C via an oxygen atom, a sulfur atom, a nitrogen atom which may be substituted, Ra or Rc to form a ring structure, R 2 It may be linked to ring B or ring C via an oxygen atom, a sulfur atom, a nitrogen atom which may be substituted, Rb or Rc to form a ring structure.

[0040] [Chemistry 12]

[0041] In formula (3), R 3 Each independently represents a cyano group, a halogen atom, a fluoroalkyl group, an acyl group, a sulfonyl group, a phosphoryl group, an optionally substituted aromatic hydrocarbon group, or an optionally substituted aromatic heterocyclic group. [About the structure of organic electroluminescent element] The region between the anode and the light-emitting layer is used as a hole transport region. The hole transport region has the function of transferring holes injected from the anode or holes generated in the hole transport region to the light-emitting layer. By placing the hole transport region between the anode and the light-emitting layer, more holes can be injected into the light-emitting layer with a lower electric field.

[0042] The hole transport region may be formed by a plurality of layers. The hole transport region is preferably a stacked structure of two or more layers, more preferably a stacked structure of four or less layers, and particularly preferably a stacked structure of three layers. In the case where the hole transport region forms a three-layer stacked structure, the first hole transport layer, the second hole transport layer, and the third hole transport layer are sequentially provided from the anode side, and preferably, each of them independently has one or more functions selected from the group consisting of a hole injection layer, a hole generating layer, a hole transport layer, and an electron blocking layer.

[0043] The region between the cathode and the light-emitting layer is used as an electron transport region. The electron transport region has the function of transferring electrons injected from the cathode or electrons generated in the electron transport region to the light-emitting layer. By placing the electron transport region between the light-emitting layer and the cathode, most electrons are injected into the light-emitting layer with a lower electric field.

[0044] The electron transport region may be formed by a plurality of layers. The electron transport region is preferably a stacked structure of two or more layers, more preferably a stacked structure of four or less layers, and particularly preferably a stacked structure of three or less layers. In the case where the electron transport region forms a three-layer stacked structure, the first electron transport layer, the second electron transport layer, and the third electron transport layer are sequentially provided from the anode side, and each of them independently has one or more functions selected from a hole blocking layer, an electron transport layer, and an electron injection layer.

[0045] In addition, a charge generating layer may be provided between the anode and the cathode, and a light emitting layer, an electron transporting region, etc. may be provided as other units.

[0046] The structure of the organic electroluminescent element according to one embodiment of the present invention is not particularly limited, and examples thereof include the structures 1) to 6) shown below.

[0047] 1): Anode / light-emitting layer / electron transport region / cathode 2): Anode / hole transport layer / light-emitting layer / electron transport layer / cathode 3): Anode / hole injection layer / hole transport layer / light-emitting layer / electron transport layer / electron injection layer / cathode 4): Anode / hole injection layer / hole generation layer / hole transport layer / light-emitting layer / electron transport layer / cathode 5): Anode / hole injection layer / hole transport layer / electron blocking layer / light-emitting layer / hole blocking layer / electron transport layer / electron injection layer / cathode 6): Anode / hole transport region / light-emitting layer / electron transport region / charge generation layer / Hole Transport region / light-emitting layer / electron transport region / cathode Below, refer to Figure 1 The organic electroluminescent element according to one embodiment of the present invention will be described in more detail. Figure 1 This is a schematic cross-sectional view showing an example of a stacked structure of an organic electroluminescent element according to one embodiment of the present invention. The organic electroluminescent element according to one embodiment of the present invention may have a bottom emission type element configuration, a top emission type element configuration, or other known element configurations.

[0048] The organic electroluminescent element 100 sequentially comprises: a substrate 1, an anode 2, a hole transport region 3, a light-emitting layer 4, an electron transport region 5, and a cathode 6. The hole transport region 3 may sequentially form a stacked structure of a first hole transport layer 31, a second hole transport layer 32, and a third hole transport layer 33 from the anode side. The electron transport region 5 may also sequentially form a stacked structure of a first electron transport layer 51, a second electron transport layer 52, and a third electron transport layer 53 from the anode 2 side. However, some of these layers and / or regions may be omitted, and other layers may be added instead. For example, a charge generation layer may be provided between the electron transport region 5 and the cathode 6, or the hole transport region 3 may be omitted, and the light-emitting layer 4 may be provided directly on the anode 2. In addition, for example, a structure may be provided in which the multiple layers are replaced by a single layer, and the single layer may be an electron injection / transport layer that has both the functions of the electron injection layer and the functions of the electron transport layer in a single layer, and has the functions of multiple layers. In addition, for example, a single-layer hole transport layer 5 and a single-layer electron transport layer 7 may each include multiple layers. [Substrate 1] The substrate is not particularly limited, and examples thereof include a glass plate, a quartz plate, a plastic plate, a plastic film, etc. In addition, in the case of a configuration in which light emission is captured from the substrate 1 side, the substrate 1 is transparent to the wavelength of light emission from the light emitting layer 4. In the case of a configuration in which light emission is captured from the cathode 6 side, the substrate 1 may also include a reflector that reflects light emission from the light emitting layer 4 toward the cathode 6 side.

[0049] Examples of light-transmitting plastic films include films made of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate (PC), cellulose triacetate (TAC), cellulose acetate propionate (CAP), and the like. [Anode 2] The anode 2 is provided between the substrate 1 and the hole transport region 3. The anode 2 can function as an anode when a current is passed through the organic electroluminescent element of one embodiment of the present invention.

[0050] In the case of a structure in which light emission is captured from the substrate 1 side, the anode 2 is formed of a material that allows the light emission to pass through or substantially pass through, or a film thickness that allows the light emission to fully pass through. In addition, in the case of a structure in which light emission is captured from the cathode 6 side, the anode 2 may also have a function of reflecting light emission from the light emitting layer 4 toward the cathode 6 side. Specifically, the anode 2 may be formed of a material that can fully reflect the light emission wavelength from the light emitting layer 4, or may be formed of a laminated structure of a material with high reflectivity and a material with appropriate high transmittance.

[0051] The material used in the anode 2 is not particularly limited in the case of extracting light emission from the substrate 1 side, and examples thereof include indium tin oxide (ITO; Indium Tin Oxide), indium zinc oxide (IZO; Indium Zinc Oxide), tin oxide, aluminum-doped tin oxide, magnesium-indium oxide, nickel-tungsten oxide, other metal oxides, metal nitrides such as gallium nitride, metal selenides such as zinc selenide, and metal sulfides such as zinc sulfide.

[0052] It should be noted that the transmission characteristics of the anode are not important in the case of an organic electroluminescent element configured to extract light only from the cathode 6. Therefore, an example of a material used for the anode in this case is gold, silver, iridium, molybdenum, palladium, platinum, or an alloy thereof. [Hole transport region 3] The hole transport region 3 is provided between the anode 2 and the light emitting layer 4 described later, and a stacked structure including a first hole transport layer 31 , a second hole transport layer 32 , and a third hole transport layer 33 is provided in order from the anode 2 side.

[0053] The first hole transport layer 31, the second hole transport layer 32, and the third hole transport layer 33 forming the hole transport region 3 each independently have one or more functions selected from the group consisting of a hole injection layer, a hole generation layer, a hole transport layer, and an electron blocking layer. These functions are described in detail below.

[0054] The hole injection layer has a function of efficiently injecting holes from the anode 2 and also has a function of efficiently injecting holes into adjacent layers.

[0055] Specific examples of materials for the hole injection layer include triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyaryl alkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers, conductive polymer oligomers (especially thiophene oligomers), porphyrin compounds, aromatic tertiary amine compounds, styrylamine compounds, etc. Among them, porphyrin compounds, aromatic tertiary amine compounds, and styrylamine compounds are preferred, and aromatic tertiary amine compounds are particularly preferred. In addition, the hole injection layer may also contain the later-described radialene compound (3). In addition, the composition may also contain the above-mentioned materials and the later-described radialene compound (3).

[0056] The hole generating layer has the function of generating holes in the adjacent layer (which is synonymous with injecting holes into the adjacent layer) by extracting electrons from the occupied molecular orbital of the compound forming the adjacent layer by applying an electric field, and transporting the obtained electrons to the anode 2 side.

[0057] Specific examples of the material of the hole generating layer include: dipyrazine [2,3-f: 2', 3'-h] quinoxaline-2,3,6,7,10,11-hexanitrile (HAT-CN), 7,7,8,8-tetracyanoquinodimethane (TCNQ), 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), 11,11,12,12-tetracyano-2,6-naphthoquinodimethane (TNAP), 15,15,16,16-tetracyanoanthraquinodimethane (TCAQ), etc. In addition, the hole generating layer may contain the later-described radialene compound (3). In addition, it may be a composition containing the above-described materials and the later-described radialene compound (3).

[0058] The hole transport layer has the function of transporting holes injected from the anode 2 , the hole injection layer, and the hole generation layer, and injecting holes into adjacent layers.

[0059] The electron blocking layer has the function of blocking electrons injected from adjacent layers into the layer. In particular, by blocking electron injection from the light-emitting layer, the total number of charges that contribute to light emission in the light-emitting layer can be increased, and even the light-emitting efficiency of the organic electroluminescent element can be improved.

[0060] Specific examples of materials for the hole transport layer and the electron blocking layer include triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyaryl alkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers, conductive polymer oligomers (especially thiophene oligomers), porphyrin compounds, aromatic tertiary amine compounds, styrylamine compounds, etc. Among them, porphyrin compounds, aromatic tertiary amine compounds, and styrylamine compounds are preferred, and aromatic tertiary amine compounds are particularly preferred. In addition, the hole transport layer or the electron transport layer may contain the axialene compound (3) described later.

[0061] Preferably, the first hole transport layer 31 assumes the function of a hole injection layer and / or a hole generation layer, and more preferably, assumes the function of a hole injection layer.

[0062] Preferably, the second hole transport layer 32 assumes the function of a hole generating layer, a hole transport layer and / or an electron blocking layer, and more preferably, assumes the function of a hole transport layer.

[0063] Preferably, the third hole transport layer 33 assumes the function of a hole transport layer and / or an electron blocking layer, and more preferably, assumes the function of an electron blocking layer.

[0064] Specific examples of aromatic tertiary amine compounds and styrylamine compounds used in the hole injection layer, hole transport layer, and electron blocking layer include: N,N,N',N'-tetraphenyl-4,4'-diaminophenyl, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1,1'-biphenyl]-4,4'-diamine (TPD), 2,2-bis(4-di-p-tolylaminophenyl)propane, 1,1-bis(4-di-p-tolylaminophenyl)cyclohexane, N,N,N',N'-tetra-p-tolyl-4,4'-diaminobiphenyl, 1,1-bis(4-di-p-tolylaminophenyl)-4-phenylcyclohexane, bis(4-dimethylamino-2-methylphenyl)phenylmethane, bis(4-di-p-tolylaminophenyl)phenylmethane, N, N'-diphenyl-N,N'-di(4-methoxyphenyl)-4,4'-diaminobiphenyl, N,N,N',N'-tetraphenyl-4,4'-diaminodiphenyl ether, 4,4'-bis(diphenylamino)quaterphenyl, N,N,N-tri(p-tolyl)amine, 4-(di-p-tolylamino)-4'-[4-(di-p-tolylamino)phenylvinyl]stilbene, 4-N,N-diphenylamino-(2-diphenylvinyl)benzene, 3-methoxy-4'-N,N-diphenylaminophenylvinylbenzene, N-phenylcarbazole, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPD), 4,4',4"-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (MTDATA), and the following compounds.

[0065] [Chemistry 13]

[0066] [Chemistry 14]

[0067] <Radialene compounds> The radialene compound contained in the hole transporting region according to one embodiment of the present invention is represented by formula (3).

[0068] [Chemistry 15]

[0069] In formula (3), R 3 Each independently represents a cyano group, a halogen atom, a fluoroalkyl group, an acyl group, a sulfonyl group, a phosphoryl group, an optionally substituted aromatic hydrocarbon group, or an optionally substituted aromatic heterocyclic group.

[0070] Hereinafter, the radialene compound represented by formula (3) may also be referred to as a radialene compound (3). Preferred embodiments of the radialene compound (3), definitions of substituents, and preferred specific examples thereof are shown below.

[0071] As R3 Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. Among them, a fluorine atom and a chlorine atom are preferred, and a fluorine atom is more preferred.

[0072] As R 3 The acyl group shown is preferably an acyl group having 2 to 10 carbon atoms including the carbon at the carbonyl site, more preferably an acyl group having 2 to 10 carbon atoms substituted with fluorine atoms, further preferably an acyl group having 2 to 10 carbon atoms in which all hydrogen atoms are substituted with fluorine atoms, and particularly preferably an acyl group having 2 to 6 carbon atoms in which all hydrogen atoms are substituted with fluorine atoms.

[0073] As R 3 The fluoroalkyl group shown is an alkyl group having 1 to 20 carbon atoms in which hydrogen atoms of the alkyl group are substituted with one or more fluorine atoms, preferably a fluoroalkyl group having 1 to 20 carbon atoms in which all hydrogen atoms are substituted with fluorine atoms, more preferably a fluoroalkyl group having 1 to 10 carbon atoms, further preferably a fluoroalkyl group having 1 to 6 carbon atoms, and particularly preferably a fluoroalkyl group having 1 to 3 carbon atoms.

[0074] As R 3 The substituted aromatic hydrocarbon group shown is preferably an aromatic hydrocarbon group having 6 to 20 ring carbon atoms which can form a linked or condensed ring and which can be substituted with one or more cyano groups, halogen atoms, acyl groups, sulfonyl groups, or phosphoryl groups, more preferably an aromatic hydrocarbon group having 6 to 20 ring carbon atoms which can form a linked or condensed ring and which can be substituted with cyano groups and / or halogen atoms, and particularly preferably a phenyl group or a biphenyl group substituted with cyano groups and / or fluorine atoms.

[0075] As R 3 The substituted aromatic heterocyclic group shown is preferably an aromatic heterocyclic group having 6 to 20 ring atoms and capable of forming a linked or condensed ring and which may be substituted with one or more cyano groups, halogen atoms, acyl groups, sulfonyl groups, or phosphoryl groups, more preferably an aromatic heterocyclic group having 6 to 20 ring atoms and capable of forming a linked or condensed ring and which may be substituted with cyano groups and / or halogen atoms, and particularly preferably a pyridyl group, pyrimidyl group, pyrazinyl group, or triazinyl group substituted with cyano groups and / or fluorine atoms. [About formula (3-a)] The radialene compound (3) preferably has a structure represented by the formula (3-a).

[0076] [Chemistry 16]

[0077] In formula (3-a), Ar 4 Each independently represents an aromatic hydrocarbon group which may be substituted, or an aromatic heterocyclic group which may be substituted.

[0078] R 3 and Ar4 The substituents of the aromatic hydrocarbon group which may be substituted and the aromatic heterocyclic group which may be substituted are each independently selected from deuterium, a cyano group, a halogen atom, a fluoroalkyl group, an acyl group, a sulfonyl group, and a phosphoryl group.

[0079] R 3 The preferred embodiment is the same as that of formula (3).

[0080] As Ar 4 The substituted aromatic hydrocarbon group shown is preferably an aromatic hydrocarbon group having 6 to 20 ring carbon atoms which can form a linked or condensed ring and which can be substituted with one or more cyano groups, halogen atoms, acyl groups, sulfonyl groups, or phosphoryl groups, more preferably an aromatic hydrocarbon group having 6 to 20 ring carbon atoms which can form a linked or condensed ring and which can be substituted with cyano groups and / or halogen atoms, and particularly preferably a phenyl group or a biphenyl group substituted with cyano groups and / or fluorine atoms.

[0081] As Ar 4 The substituted aromatic heterocyclic group shown is preferably an aromatic heterocyclic group having 6 to 20 ring atoms and capable of forming a linked or condensed ring and which may be substituted with one or more cyano groups, halogen atoms, acyl groups, sulfonyl groups, or phosphoryl groups, more preferably an aromatic heterocyclic group having 6 to 20 ring atoms and capable of forming a linked or condensed ring and which may be substituted with cyano groups and / or halogen atoms, and particularly preferably a pyridyl group, pyrimidyl group, pyrazinyl group, or triazinyl group substituted with cyano groups and / or fluorine atoms. [About formula (3-b)] The radialene compounds (3) and (3-a) preferably have a structure represented by the formula (3-b).

[0082] [Chemistry 17]

[0083] In formula (3-b), R 31 Each is independently selected from deuterium, a cyano group, a halogen atom, a fluoroalkyl group, an acyl group, a sulfonyl group, and a phosphoryl group.

[0084] s is an integer of 1-5 each independently.

[0085] R 31 The preferred embodiment of the halogen atom, fluoroalkyl group, and acyl group shown in R 3 same.

[0086] R 31 It is preferably selected from a cyano group, a fluorine atom and a fluoroalkyl group, more preferably a cyano group and / or a fluorine atom, and further preferably a cyano group and a fluorine atom. [Preferred examples of the radialene compounds (3), (3-a) and (3-b)] The radialene compound (3) as one embodiment of the present invention is more preferably a radialene compound represented by any one of the following compounds 3-1 to 3-148.

[0087] [Chemistry 18]

[0088] [Chemistry 19]

[0089] [Chemistry 20]

[0090] [Chemistry 21]

[0091] [Chemistry 22]

[0092] [Chemistry 23]

[0093] [Chemistry 24]

[0094] [Chemistry 25]

[0095] [Chemistry 26]

[0096] [Chemistry 27]

[0097] [Chemistry 28]

[0098] [Chemistry 29]

[0099] [Chemistry 30]

[0100] Among them, the radialene compound represented by Formula 3-1 is particularly preferred in terms of achieving excellent driving voltage characteristics, current efficiency characteristics, and efficiency change characteristics of the device. [Regarding the application of the radialene compound (3) in an organic electroluminescent device] The radialene compound (3) involved in one embodiment of the present invention is used in the hole transport region. The hole transport region preferably forms a stacked structure comprising a plurality of layers, wherein the layer comprising the radialene compound (3) is preferably used in a layer not in contact with the light-emitting layer, more preferably in a layer functioning as the hole injection layer, hole generation layer, or hole transport layer, and further preferably in a hole injection layer or a hole generation layer.

[0101] The layer containing the radialene compound (3) may be formed only of the radialene compound (3), or may be formed of a composition of other compounds and the radialene compound (3). In particular, in terms of the excellent driving voltage of the element, it is preferably formed of a composition with other compounds, and in this case, the composition ratio of the radialene compound is more preferably 0.1% to 20%, further preferably 0.5% to 10%, and particularly preferably 0.5% to 5%.

[0102] The layer formed by the composition of the radialene compound (3) and other compounds can be formed by a co-evaporation method in which the radialene compound (3) and the monomers of the other compounds are heated and evaporated simultaneously, or a mixture of the radialene compound (3) and the other compounds is heated and evaporated. From the viewpoint of controlling the composition ratio of the radialene compound (3) in the formed layer, it is preferred to form the layer by the co-evaporation method.

[0103] The compound to be deposited together with the radialene compound (3) to form the composition is preferably a compound listed as specific examples of the hole injection material and hole transport material, and more preferably an aromatic tertiary amine compound. [Luminous layer 4] The light-emitting layer 4 is provided between the hole transport region 3 and the electron transport region 5 described later.

[0104] Examples of materials for the light-emitting layer include phosphorescent materials, fluorescent materials, and thermally activated delayed fluorescent materials. In the light-emitting layer, excitons are electrically generated by recombination of electron-hole pairs, and light is generated when the excitons are deactivated.

[0105] The light-emitting layer 4 may include a single low molecular weight material or a single polymer material, and more generally, includes a host material obtained by doping with a guest compound. Examples of the guest material include fluorescent compounds, phosphorescent compounds, delayed fluorescent compounds, and the like. The light emission is mainly generated by the guest material and can emit any color. In addition, the light-emitting layer 4 may include a boron compound (1) described in detail later.

[0106] Examples of the host material include compounds having a biphenyl group, a fluorenyl group, a triphenylalkyl group, a carbazolyl group, a pyrene group, a dibenzofuranyl group, a dibenzothiophene group, and an anthracene group. More specifically, DPVBi (4,4'-bis(2,2-diphenylvinyl)-1,1'-biphenyl), BCzVBi (4,4'-bis(9-ethyl-3-carbazole vinyl) 1,1'-biphenyl), TBADN (2-tert-butyl-9,10-di(2-naphthyl)anthracene), AND (9,10-di(2-naphthyl)anthracene), CBP (4,4'-bis(carbazole-9-yl)biphenyl), CDBP (4,4'-bis(carbazole-9-yl)-2,2'-dimethylbiphenyl), 2-(9-phenylcarbazole-3-yl)-9-[4-(4-phenylphenylquinazolin-2-yl)carbazole, 9,10-bis(biphenyl)anthracene, etc. are mentioned.

[0107] Examples of fluorescent compounds include boron compounds (1), anthracene, pyrene, tetracene, xanthene, perylene, rubrene, coumarin, rhodamine, quinacridone, dicyanomethylenepyran compounds, thiopyran compounds, polymethine compounds, pyrylium, thiopyranium compounds, fluorene compounds, diindenopyrene compounds, indenoperylene compounds, bis(azinyl)amine boron compounds, bis(azinyl)methane compounds, quinolone compounds, etc. The fluorescent dopant may be a combination of two or more selected from these.

[0108] Examples of the phosphorescent compound include metal complexes such as iridium complexes, platinum complexes, palladium complexes, and osmium complexes.

[0109] Specific examples of fluorescent compounds and phosphorescent compounds include: Alq3 (tris(8-hydroxyquinoline)aluminum), DPAVBi (4,4'-bis[4-(di-p-tolylamino)phenylvinyl]biphenyl), perylene, bis[2-(4-n-hexylphenyl)quinoline](acetylacetonate)iridium(III), Ir(PPy)3 (tris(2-phenylpyridine)iridium(III)), and FIrPic (bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl)iridium(III))).

[0110] The thermally activated delayed fluorescent material can be used as any of the host material or the guest material. In addition, the thermally activated delayed fluorescent material, which does not emit light itself, can also play the role of efficiently transmitting excitation energy to the fluorescent compound that forms the light-emitting layer simultaneously with the thermally activated delayed fluorescent material.

[0111] Specific examples of thermally activated delayed fluorescence include boron compounds (1), 4Cz-IPN (2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile), 5Cz-BN (2,3,4,5,6-penta(9-carbazolyl)-benzonitrile), DACTII (2-[3,6-bis(diphenylamino)carbazol-9-ylphenyl]-4,6-diphenyl-1,3,5-triazine), and the like.

[0112] In addition, the light-emitting material is not limited to being contained only in the light-emitting layer. For example, the layer adjacent to the light-emitting layer (hole transport layer 5 or electron transport layer 7) may contain the light-emitting material. This can further improve the current efficiency of the organic electroluminescent element.

[0113] The light-emitting layer may have a single-layer structure including one or two or more materials, or may have a stacked structure including multiple layers of the same composition or different compositions. <Boron compounds> The boron compound contained in the light-emitting layer according to one embodiment of the present invention is represented by formula (1).

[0114] [Chemistry 31]

[0115] In formula (1), ring A, ring B and ring C each independently represent an aromatic hydrocarbon ring having 6 to 20 ring atoms which may have a substituent, or an aromatic heterocyclic ring having 5 to 20 ring atoms which may have a substituent, Ra, Rb, and Rc each independently represent deuterium, a cyano group, an alkyl group having 1 to 20 carbon atoms, an aromatic hydrocarbon group having 6 to 20 ring atoms, or a heteroaromatic group having 5 to 20 ring atoms. a, b, and c are each independently an integer of 0 to 4, Ring A and ring B may be linked via an oxygen atom, a sulfur atom, N-R', Ra or Rb. R 1 , R 2 , R' each independently represents an alkyl group having 1 to 20 carbon atoms which may have a substituent, an aromatic hydrocarbon group having 6 to 20 ring atoms which may have a substituent, or a heteroaromatic group having 5 to 20 ring atoms which may have a substituent. R 1 It may be linked to ring A or ring C via an oxygen atom, a sulfur atom, a nitrogen atom which may be substituted, Ra or Rc to form a ring structure, R 2 It may be linked to ring B or ring C via an oxygen atom, a sulfur atom, a nitrogen atom which may be substituted, Rb or Rc to form a ring structure.

[0116] Hereinafter, the boron compound represented by formula (1) may also be referred to as compound (1). The definitions and preferred specific examples of the ring structure and substituents formed in compound (1) are shown below. [About Ring A to Ring C] Ring A, ring B and ring C are each independently selected from an aromatic hydrocarbon ring having 6 to 20 ring atoms which may have a substituent and an aromatic heterocyclic ring having 5 to 20 ring atoms which may have a substituent.

[0117] Ring A, Ring B and Ring C are each independently preferably an aromatic hydrocarbon ring having 6 to 18 ring atoms which may have a substituent or an aromatic heterocyclic ring having 5 to 18 ring atoms which may have a substituent, more preferably an aromatic hydrocarbon ring having 6 to 12 ring atoms or an aromatic heterocyclic ring having 5 to 12 ring atoms, further preferably an aromatic hydrocarbon ring having 6 to 9 ring atoms or an aromatic heterocyclic ring having 5 to 9 ring atoms, more preferably benzene, benzofuran, benzothiophene, indole, benzimidazole, benzothiazole, benzoxazole, and particularly preferably benzene.

[0118] Ring A and ring B may be linked via an oxygen atom, a sulfur atom, N-R', Ra or Rb described below, and ring A and ring B are preferably linked or unlinked via N-R', and ring A and ring B are more preferably unlinked. [About Ra, Rb, Rc] Ra, Rb, and Rc are each independently selected from the group consisting of deuterium, cyano, an alkyl group having 1 to 20 carbon atoms, an aromatic hydrocarbon group having 6 to 20 ring atoms, and an aromatic heterocyclic ring having 5 to 20 ring atoms.

[0119] Ra, Rb, and Rc are each independently preferably deuterium, an alkyl group having 1 to 20 carbon atoms, or a heteroaromatic group having 5 to 20 ring atoms, more preferably deuterium or an alkyl group having 1 to 20 carbon atoms, and still more preferably an alkyl group having 1 to 20 carbon atoms. [About a, b, c] a, b, and c are each independently an integer of 0 to 4, are each independently preferably 0 to 2, are each independently more preferably 0 to 1, and are further preferably 1. [About R 1 , R 2 , R'] R 1 , R 2 , R' each independently represents: an alkyl group having 1 to 20 carbon atoms which may have a substituent, an aromatic hydrocarbon group having 6 to 20 ring atoms which may have a substituent, or a heteroaromatic group having 5 to 20 ring atoms which may have a substituent; R 1 , R 2, R' are each independently preferably an aromatic hydrocarbon group having 6 to 20 ring atoms which may have a substituent, or a heteroaromatic group having 5 to 20 ring atoms which may have a substituent, more preferably an aromatic hydrocarbon group having 6 to 20 ring atoms which may have a substituent, further preferably an aromatic hydrocarbon group having 6 to 20 ring atoms substituted by an alkyl group, and particularly preferably a phenyl group substituted by an alkyl group.

[0120] R 1 It may be linked to ring A or ring C via an oxygen atom, a sulfur atom, a nitrogen atom which may be substituted, Ra or Rc to form a ring structure, R 2 The ring structure may be formed by linking to the ring B or the ring C via an oxygen atom, a sulfur atom, a nitrogen atom which may be substituted, Rb or Rc. [Preferred examples of the boron compound (1)] In terms of achieving both excellent driving voltage characteristics and excellent current efficiency characteristics, a boron compound represented by any one of Compounds 1-1 to 1-54 is more preferable.

[0121] [Chemistry 32]

[0122] [Chemistry 33]

[0123] [Chemistry 34]

[0124] [Chemistry 35]

[0125] Among them, particularly in terms of the excellent driving voltage characteristics, current efficiency characteristics, and efficiency change characteristics of the element, the boron compounds shown in 1-1, 1-2, 1-11, 1-12, 1-17, 1-18, 1-21, and 1-22 are preferred, 1-1, 1-11, and 1-17 are more preferred, and 1-1 is particularly preferred. [Electron transport region 5] The electron transport layer 5 is provided between the light emitting layer 4 and the cathode 6 described later, and a stacked structure including a first electron transport layer 51 , a second electron transport layer 52 , and a third electron transport layer 53 is provided in order from the anode 2 side.

[0126] The triazine compound represented by formula (2) is contained in the electron transporting region 5. The triazine compound may be contained throughout a plurality of layers present in the electron transporting region.

[0127] The first electron transport layer 51, the second electron transport layer 52, and the third electron transport layer 53 forming the electron transport region 5 each independently have one or more functions selected from the group consisting of an electron injection layer, an electron generation layer, an electron transport layer, and a hole blocking layer. These functions will be described in detail later.

[0128] The electron injection layer has a function of efficiently injecting electrons from the cathode 6 or the charge generation layer, and also has a function of efficiently injecting electrons into an adjacent layer.

[0129] Specific examples of materials for the electron injection layer include: metals such as lithium (Li), potassium (K), cesium (Cs), and ytterbium (Yb); inorganic salts such as lithium fluoride (LiF), sodium fluoride (NaF), potassium fluoride (KF), lithium carbonate (Li2CO3), sodium carbonate (Na2CO3), potassium carbonate (K2CO3), and cesium carbonate (Cs2CO3); organic metal complexes such as 8-hydroxyquinoline lithium (Liq) and bis(8-hydroxyquinoline) zinc; or combinations thereof with the triazine compound represented by formula (2).

[0130] The electron transport layer has the function of transporting electrons injected from the charge generation layer, the cathode, and the electron injection layer and injecting electrons into an adjacent layer.

[0131] The hole blocking layer has the function of blocking holes injected into the layer from the adjacent layer, and in particular, by blocking hole injection from the light-emitting layer, the total number of charges contributing to light emission in the light-emitting layer can be increased, and even the light-emitting efficiency of the organic electroluminescent element can be improved.

[0132] The electron transport layer and the hole blocking layer can contain the triazine compound shown in formula (2). As a specific example of the material of the electron transport layer and the hole blocking layer, in addition to the triazine compound shown in formula (2), it can also contain a conventionally known electron transport material. As conventionally known electron transport materials, for example, there can be cited: 8-hydroxyquinoline lithium (Liq), bis(8-hydroxyquinoline) zinc, bis(8-hydroxyquinoline) copper, bis(8-hydroxyquinoline) manganese, tris(8-hydroxyquinoline) aluminum, tris(2-methyl-8-hydroxyquinoline) aluminum, tris(8-hydroxyquinoline) gallium, bis(10-hydroxybenzo[h]quinoline) beryllium, bis(10-hydroxybenzo[h]quinoline) zinc, bis(2-methyl-8-quinoline) chlorogallium, bis(2-methyl-8-quinoline)(o-cresol) gallium, bis(2-methyl-8-quinoline)-1-naphthol aluminum, or bis(2-methyl-8-quinoline)-2-naphthol Gallium, 2-[3-(9-phenanthrenyl)-5-(3-pyridyl)phenyl]-4,6-diphenyl-1,3,5-triazine, and 2-(4,"-di-2-pyridyl[1,1':3',1"-terphenyl]-5-yl)-4,6-diphenyl-1,3,5-triazine, BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), Bphen (4,7-diphenyl-1,10-phenanthroline), BAlq (bis(2-methyl-8-quinolinol)-4-(phenylphenol)aluminum) and bis(10-hydroxybenzo[h]quinolinol)beryllium), and combinations thereof. In addition, a combination doped with these compounds and Liq may also be used. <Triazine compounds> The triazine compound contained in the electron transporting region according to one embodiment of the present invention is represented by formula (2).

[0133] [Chemistry 36]

[0134] In formula (2), Ar 1 represents a phenyl group which may be substituted with an alkyl group having 1 to 6 carbon atoms, a naphthyl group which may be substituted with an alkyl group having 1 to 6 carbon atoms, or a biphenyl group which may be substituted with an alkyl group having 1 to 6 carbon atoms, Ar 2 It represents a phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, a pyridyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, a phenylpyridyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, a pyridylphenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, or a biphenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms. Ar 3 It represents a phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, or a biphenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms.

[0135] Hereinafter, the triazine compound represented by formula (2) may also be referred to as triazine compound (2). Definitions of substituents in triazine compound (2) and preferred specific examples thereof are shown below. [About Ar 1 ] Ar 1 Selected from phenyl, naphthyl, biphenyl. In terms of both excellent driving voltage characteristics and current efficiency characteristics, Ar 1 Preferred are phenyl and biphenyl groups, and more preferred are phenyl and biphenyl-4-yl groups. [About Ar 2 ] Ar 2 A phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, a pyridyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, a phenylpyridyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, a pyridylphenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, and a biphenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms. In terms of both excellent driving voltage characteristics and current efficiency characteristics, Ar 2 A phenyl group, a pyridyl group, and a biphenyl group are preferred, a phenyl group and a biphenyl group are more preferred, and a phenyl group is particularly preferred. [About Ar 3 ] Ar 3 It is selected from a phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, and a biphenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms. In terms of both excellent driving voltage characteristics and current efficiency characteristics, Ar 3 Preferred are phenyl, biphenyl-2-yl and biphenyl-4-yl. [Preferred examples of the triazine compound (2)] The triazine compound (2) as one embodiment of the present invention is more preferably a triazine compound represented by any one of the following compounds 2-1 to 2-80.

[0136] [Chemistry 37]

[0137] [Chemistry 38]

[0138] [Chemistry 39]

[0139] [Chemistry 40]

[0140] Among them, in particular, in the invention that takes into account the excellent driving voltage characteristics, current efficiency characteristics and efficiency change characteristics of the element, the triazine compounds represented by Formula 2-1, Formula 2-2, Formula 2-4, Formula 2-5, Formula 2-9, Formula 2-22, and Formula 2-24 are preferred. [Regarding the application of triazine compound (2) in organic electroluminescent device] The triazine compound (2) according to one embodiment of the present invention is used in an electron transport region. The electron transport region preferably forms a laminated structure including a plurality of layers, wherein the triazine compound (2) is more preferably used in a layer functioning as the electron transport layer or hole blocking layer, and is further preferably used in an electron transport layer.

[0141] When the triazine compound (2) is used in the electron transport layer, the electron transport layer may be formed of the triazine compound (2) alone or in combination with other compounds. In particular, in terms of exhibiting excellent drive voltage of the element, it is preferably formed of a combination with other compounds, and in this case, the weight composition of the triazine compound (2) is more preferably 20% to 80%, further preferably 30% to 70%, and particularly preferably 40% to 60%.

[0142] The layer formed of the composition of the triazine compound (2) and other compounds can be formed by a co-evaporation method in which the triazine compound (2) and other compounds are heated and evaporated simultaneously, or a mixture of the triazine compound (2) and other compounds is heated and evaporated. From the viewpoint of controlling the composition ratio of the triazine compound (2) in the formed layer, it is preferred to form the layer by the co-evaporation method.

[0143] The compound to be deposited together with the triazine compound (2) to form a composition is preferably a compound listed as a specific example of the material used in the electron transport and hole blocking layer or Liq, and more preferably Liq.

[0144] The triazine compound (2) according to one embodiment of the present invention can be synthesized by appropriately combining known reactions (for example, Suzuki-Miyaura cross-coupling reaction, etc.).

[0145] For example, the triazine compound (2) according to one embodiment of the present invention can be synthesized according to any of the following reaction formulas (a) to (c), but the present invention should not be construed as being limited to these examples.

[0146] [Chemistry 41]

[0147] [Chemistry 42]

[0148] [Chemistry 43]

[0149] In reaction formulas (a) to (c), Ar 1 ,Ar 2 and Ar 3 The definition of is the same as that of formula (1).

[0150] X represents independently a disengagement group. As the disengagement group, it is not particularly limited, for example, a chlorine atom, a bromine atom, an iodine atom, a trifluoromethanesulfonyloxy group etc. can be mentioned. Wherein, in terms of good reaction yield, a bromine atom or a chlorine atom is preferred. However, from the viewpoint of the availability of raw materials, it is sometimes preferred to use a trifluoromethanesulfonyloxy group.

[0151] M each independently represents ZnR as a metal-containing group 1 MgR 2 or Sn(R 3) 3; or as a boron-containing group B(OR 4 )2. Among them, R 1 and R 2 Each independently represents a chlorine atom, a bromine atom or an iodine atom; R 3 represents an alkyl group having 1 to 4 carbon atoms or a phenyl group; R 4 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group; B(OR 4 ) The two R in 2 4 They can be the same or different. 4 It is also possible to form a ring by including an oxygen atom and a boron atom as a whole.

[0152] As ZnR 1 MgR 2 , ZnCl, ZnBr, ZnI, MgCl, MgBr, MgI and the like can be exemplified.

[0153] As Sn(R 3 )3, Sn(Me)3, Sn(Bu)3, etc. can be exemplified.

[0154] As B(OR 4 )2, B(OH)2, B(OMe)2, B(O i Pr)2, B(OBu)2, etc. In addition, as two R 4 When B(OR 4 The examples of )2 are not particularly limited, and the following groups (I) to (VI) can be exemplified. In view of good yield, the group represented by (II) is preferred.

[0155] [Chemistry 44]

[0156] The production methods represented by reaction formulas (a) to (c) are described in more detail by taking the production method represented by reaction formula (b) as an example. The production method represented by reaction formula (b) is a method of reacting a mixture of Ar and Ar in the presence of a palladium catalyst. 2 or Ar 3 The organometallic compounds are sequentially used for the reaction to obtain the triazine compound (2). 2 or Ar 3 Alternatively, it is also possible to react with an organometallic compound containing Ar 2 The intermediate product is temporarily separated and then, in the presence of a palladium catalyst, a catalyst containing Ar is used to obtain an intermediate product. 3 The triazine compound (2) is obtained by reacting an organic metal compound containing Ar 3 The triazine compound (2) can also be obtained by first using an organometallic compound in the reaction. [Cathode 6] The cathode 6 is provided to face the anode 2 with the electron transport region 5 interposed therebetween. The cathode 6 can function as a cathode when a current is passed through the organic electroluminescent element of one embodiment of the present invention.

[0157] In the case of an organic electroluminescent element configured to capture only the light emitted through the anode 2 , the cathode 6 can be formed of any conductive material.

[0158] Examples of materials for the cathode 6 include lithium, sodium, sodium-potassium alloy, magnesium, silver, magnesium / copper mixtures, magnesium / silver mixtures, magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al2O3) mixtures, indium, indium-zinc oxide (IZO; Indium Zinc Oxide), lithium / aluminum mixtures, and rare earth metals such as ytterbium.

[0159] In the case of an organic electroluminescent element configured to extract light only from the cathode 6 side, a transparent electrode material such as indium zinc oxide (IZO) or a metal material such as silver, aluminum, or a silver / magnesium mixture may be formed to a film thickness sufficient to transmit the light. [Method for forming each layer] Each layer other than the electrodes (anode, cathode) described above can be formed by thin-filming the material of each layer (together with materials such as a binder resin and a solvent as necessary) by a known method such as vacuum evaporation, spin coating, casting, LB (Langmuir-Blodgett method) or the like.

[0160] The film thickness of each layer formed in this way is not particularly limited and can be appropriately selected depending on the situation, but is usually in the range of 1 nm to 5 μm.

[0161] The anode 2 and the cathode 6 can be formed by thinning the electrode material by evaporation, sputtering, etc. A pattern can be formed by using a mask of a desired shape during evaporation or sputtering, or a pattern of a desired shape can be formed by photolithography after forming a thin film by evaporation, sputtering, etc.

[0162] The thickness of the anode 2 and cathode 6 is preferably 1 μm or less, more preferably 5 nm or more and 200 nm or less. Generally, when a material with low transmittance is used for an electrode on the side that captures light, the transmittance can be ensured by forming a film with a thickness of 30 nm or less, and the electrode can function as a transparent electrode.

[0163] The organic electroluminescent element involved in one embodiment of the present invention can be used as a lamp such as a light source for lighting or exposure, or as a projection device for projecting images, or as a display device (display) for directly visually recognizing static images or dynamic images. When used as a display device for dynamic image reproduction, the driving method can be a simple matrix (passive matrix) method or an active matrix method. In addition, by using two or more organic electroluminescent elements of this method with different luminous colors, a full-color display device can be produced. Example

[0164] Hereinafter, the present invention will be described in more detail based on Examples, but it should be construed that the present invention is not limited to these Examples at all.

[0165] 1 The H-NMR spectrum was measured using Gemini 200 (manufactured by Varian) or Bruker ASCEND 400 (400 MHz; manufactured by BRUKER).

[0166] The light emission characteristics of the organic electroluminescent element were evaluated by applying a direct current to the produced element at room temperature using a luminance meter (product name: BM-9, manufactured by TOPCON TECHNOHOUSE CORPORATION). Synthesis Example-1 (Synthesis of Compound 2-1)

[0167] [Chemistry 45]

[0168] Under argon atmosphere, 2-chloro-4,6-bis(biphenyl-4-yl)-1,3,5-triazine (11.0 g, 26.2 mmol), 5'-(5,5-dimethyl-1,3,2-dioxaborin-2-yl)-1,1':3',1":2",1"'-quaterphenyl (12.1 g, 28.8 mmol), tetrakis(triphenylphosphine)palladium (0.91 g, 0.79 mmol) and 2 M-potassium phosphate aqueous solution (39.3 mL) was suspended in THF (349 mL) and refluxed for 3 hours. After cooling, water and methanol were added to the reaction mixture, and the solid was filtered out and washed with water and methanol to obtain 2-(1,1':3',1":2",1"'-tetraphenyl-5'-yl)-4,6-bis(biphenyl-4-yl)-1,3,5-triazine (2-1) (yield 17.9 g, yield 99%). Synthesis Example-2 (Synthesis of Compound 2-2)

[0169] [Chemistry 46]

[0170] Under argon atmosphere, 2-(3-bromo-5-chlorophenyl)-4,6-bis(biphenyl-4-yl)-1,3,5-triazine (5.75 g, 10.0 mmol), 2-biphenylboronic acid (4.75 g, 24.0 mmol), 3M-aqueous potassium carbonate solution (16 mL), palladium acetate (22.4 mg, 0.1 mmol) and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (XPhos, 95.3 mg, 0.2 mmol) were suspended in THF (100 mL) and refluxed for 96 hours. After cooling, water and methanol were added to the reaction mixture, and the solid was filtered out and washed with water and methanol to obtain 2-(1,1':2',1":3",1"':2"',1""-pentaphenyl-5"-yl)-4,6-bis(biphenyl-4-yl)-1,3,5-triazine (2-2) (yield 7.18 g, yield 94%). Synthesis Example-3 (Synthesis of Compound 2-22)

[0171] [Chemistry 47]

[0172] Under an argon atmosphere, 1,3-dibromo-5-chlorobenzene (20.0 g, 74.0 mmol), 2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-biphenyl (42.5 g, 151.7 mmol), 3M-potassium carbonate aqueous solution (110 mL) and tetrakis(triphenylphosphine)palladium (2.56 g, 2.22 mmol) were suspended in THF (245 mL) and refluxed for 122 hours. After cooling, toluene was added to the reaction mixture, and the organic layer was separated and extracted. The obtained organic layer was removed by vacuum distillation, and the obtained solid was recrystallized from toluene to obtain 5"-chloro-1,1':2',1":3",1"':2"',1""-pentabiphenyl (yield 29.7 g, yield 96%).

[0173] [Chemistry 48]

[0174] Under argon atmosphere, 5"-chloro-1,1':2',1":3",1"':2"',1""-pentaphenyl (29.7 g, 71.2 mmol), neopentyl glycol diborate (17.7 g, 78.3 mmol), potassium acetate (0.16 g, 0.71 mmol), palladium acetate (20.9 g, 213.5 mmol) and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (XPhos, 0.67 mg, 1.42mmol) was suspended in THF (356mL) and refluxed for 27 hours. Then, the solvent was distilled off under reduced pressure, and methanol was added to the obtained residue. The obtained solid was filtered and dried under reduced pressure to obtain the target 5"-(5,5-dimethyl-1,3,2-dioxaborohexane-2-yl)-1,1':2',1":3",1"':2"',1""-pentaphenyl (yield 14.7g, yield 42%).

[0175] [Chemistry 49]

[0176] Under argon atmosphere, 2-chloro-4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazine (5.56 g, 16.2 mmol), 5"-(5,5-dimethyl-1,3,2-dioxaborin-2-yl)-1,1':2',1":3",1"':2"',1""-pentaphenyl (24.0 g, 48.5 mmol), tetrakis(triphenylphosphine)palladium (0.56 g, 0.49 mmol) and 2M potassium phosphate aqueous solution were added. (24.0 mL) was suspended in THF (324 mL) and refluxed for 23 hours. After cooling, water and methanol were added to the reaction mixture, and the solid was filtered out and washed with water and methanol. The obtained solid was crystallized with toluene to obtain 2-(1,1':2',1":3",1"':2"',1""-pentabiphenyl-5"-yl)-4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazine (2-22) (yield 11.1 g, yield 99%). Synthesis Example-4 (Synthesis of Compound 2-24)

[0177] [Chemistry 50]

[0178] Under an argon atmosphere, 3-bromo-5-chloro-1,1':2',1"-terphenyl (g, mmol), 4-biphenylboric acid (g, mmol), tetrakis(triphenylphosphine)palladium (g, mmol) and 2M-potassium phosphate aqueous solution (58.9 mL) were suspended in THF (393 mL) and refluxed for 21 hours. After cooling, the organic layer was subjected to liquid separation extraction, and the obtained organic layer was removed by reduced pressure distillation. The solid obtained by adding ethanol to the obtained residue was filtered to obtain the target 5"-chloro-1,1':2',1":3",1"':4"',1""-pentaphenyl (yield 24 g, yield 100%).

[0179] [Chemistry 51]

[0180] Under argon atmosphere, 5"-chloro-1,1':2',1":3",1"':4"',1""-pentaphenyl (23.1 g, 55.5 mmol), bis(pinacolato)diboron (16.9 g, 66.5 mmol), potassium acetate (16.3 g, 166.4 mmol), palladium acetate (0.25 g, 1.11 mmol) and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (XPhos, 1.06 mM) were added. g, 2.22mmol) was suspended in THF (555mL) and refluxed for 19 hours. Then, the solvent was distilled off under reduced pressure, and methanol was added to the obtained residue. The obtained solid was filtered and dried under reduced pressure to obtain the target 5"-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1,1':2',1":3",1"':4"',1""-pentaphenyl (yield 22.0g, yield 78%).

[0181] [Chemistry 52]

[0182] Under argon atmosphere, 2-chloro-4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazine (13.5 g, 39.3 mmol), 5"-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1,1':2',1":3",1"':4"',1""-pentaphenyl (22.0 g, 43.2 mmol), tetrakis(triphenylphosphine)palladium (0.91 g, 0.79 mmol) and 2M potassium phosphate aqueous solution were added. The solution (58.9 mL) was suspended in THF (393 mL) and refluxed for 21 hours. After cooling, water and methanol were added to the reaction mixture, and the solid was filtered out and washed with water and methanol. The obtained solid was recrystallized from toluene to obtain 2-(1,1':2',1":3",1"':4"',1""-pentabiphenyl-5"-yl)-4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazine (2-24) (yield 21.1 g, yield 85%).

[0183] In addition, triazine compound 2-4 was synthesized by the same method as the production method shown in Synthesis Example-1.

[0184] The structural formulas and abbreviations of the compounds used in the preparation and performance evaluation of the organic electroluminescent device are shown below.

[0185] [Chemistry 53]

[0186] Example-1 (refer to Figure 1 ) (Preparation of substrate 1 and anode 2) A glass substrate with a 2 mm wide indium tin oxide (ITO) film (thickness 110 nm) patterned into stripes and an ITO transparent electrode was prepared as a substrate having an anode on its surface. The substrate was then cleaned with isopropyl alcohol and then surface treated by ozone ultraviolet cleaning. (Preparation for vacuum deposition) On the cleaned and surface-treated substrate, each layer is vacuum-deposited by vacuum deposition to form each layer in a stacked manner.

[0187] First, the glass substrate is introduced into a vacuum deposition tank and the pressure is reduced to 1.0×10 -4 Pa. Then, the following procedures were followed to prepare the films according to the film forming conditions of each layer. (Fabrication of the First Hole Transport Layer 31) The sublimation-purified HTL-1 and the compound 3-1 of one embodiment of the present invention were formed into a film with a thickness of 10 nm at a rate of 0.15 nm / sec to form the first hole transport layer 31 . (Fabrication of Second Hole Transport Layer 32) The sublimation purified HTL-1 was formed into a film with a thickness of 85 nm at a rate of 0.15 nm / sec to form the second hole transport layer 32 . (Fabrication of the Third Hole Transport Layer 33) The sublimation purified EBL-1 was formed into a film with a thickness of 5 nm at a rate of 0.15 nm / sec to form the third hole transport layer 33 . (Production of Light Emitting Layer 4) Sublimation-purified BH-1 and compound 1-1 of one embodiment of the present invention were formed into a 20 nm film at a ratio of 95:5 (mass ratio) to prepare the light-emitting layer 4. The film formation rate was 0.18 nm / sec. (Fabrication of First Electron Transport Layer 51) The HBL-1 purified by sublimation was formed into a film with a thickness of 6 nm at a rate of 0.05 nm / sec to form the first electron transport layer 51 . (Fabrication of Second Electron Transport Layer 52) Compound 2-1 and Liq were deposited into a film with a thickness of 25 nm at a ratio of 50:50 (mass ratio) to form the second electron transport layer 52. The film deposition rate was 0.15 nm / sec. (Fabrication of the Third Electron Transport Layer 53) Ytterbium was deposited to a thickness of 2 nm to form the third electron transport layer 53. The film deposition rate was 0.01 nm / sec. (Production of cathode 6) Finally, a metal mask was arranged so as to be orthogonal to the ITO stripes on the substrate, and a film was formed as the cathode 6. The cathode was a two-layer structure made by forming silver / magnesium (mass ratio 9 / 1) and silver in 12nm and 90nm layers, respectively. The film forming speed of silver / magnesium was 0.5nm / sec, and the film forming speed of silver was 0.2nm / sec.

[0188] Through the above processing, the Figure 1 The luminous area shown is 4mm 2 Organic electroluminescent element 100. In addition, each film thickness was measured using a stylus film thickness meter (DEKTAK, manufactured by Bruker).

[0189] The device was sealed in a nitrogen atmosphere glove box with an oxygen and water concentration of 1 ppm or less. The sealing was performed using a bisphenol F epoxy resin (manufactured by Nagase ChemteX Corporation) on a glass sealing cover and a film-forming substrate (device).

[0190] A direct current was applied to the organic electroluminescent element prepared as described above, and the luminance characteristics were evaluated using a luminance meter (product name: BM-9, manufactured by TOPCON TECHNOHOUSE CORPORATION). As the luminance characteristics, a voltage was applied and the luminance was measured to be 1000 cd / m 2 The driving voltage (V) and current efficiency (cd / A) at the time of the reaction were calculated. It should be noted that the driving voltage and current efficiency are relative values ​​with the result in Comparative Example-1 described later as a reference value (100). In addition, the efficiency change was calculated based on the following definition.

[0191] Efficiency change = (1000cd / m 2 Current efficiency at 10cd / m 2 Current efficiency at The closer the value calculated by the above formula is to 1.0, the smaller the change in efficiency is in a wide brightness range. Furthermore, the device fabricated as described above was changed from a luminance of 1000 cd / m 2 After continuous driving for 50 hours, the voltage was applied again and the brightness was measured to be 1000cd / m 2 The current efficiency after continuous driving (cd / A) was calculated based on the following definition.

[0192] Efficiency change after continuous driving = (1000cd / m 2 Current efficiency after continuous driving) / (1000cd / m 2 Current efficiency at The closer the value calculated by the above formula is to 1.0, the smaller the change in efficiency of the element before and after continuous driving is. Table 1 shows the obtained measurement results. Example-2 The obtained measurement results are shown in Table 1. In the device example 1, an organic electroluminescent device was prepared and evaluated by the same method as in the example 1 except that the compound 2-2 was used instead of the compound 2-1. Example-3 The obtained measurement results are shown in Table 1. In the device example 1, an organic electroluminescent device was prepared and evaluated by the same method as in the example 1 except that the compound 2-22 was used instead of the compound 2-1. Example-4 The obtained measurement results are shown in Table 1. In the device example 1, an organic electroluminescent device was prepared and evaluated by the same method as in the example 1 except that the compound 2-24 was used instead of the compound 2-1. Example-5 An organic electroluminescent device was prepared and evaluated in the same manner as in Example 1, except that Compound 2-4 was used instead of Compound 2-1. The obtained measurement results are shown in Table 1. Comparative Example-1 The obtained measurement results are shown in Table 1. In the device example 1, an organic electroluminescent device was prepared and evaluated by the same method as in the example 1, except that ETL-1 was used instead of the compound 2-1. Comparative Example-3 The obtained measurement results are shown in Table 1. In the device example 1, an organic electroluminescent device was prepared and evaluated by the same method as in the example 1, except that ETL-2 was used instead of the compound 2-1. Comparative Example-4 An organic electroluminescent device was prepared and evaluated in the same manner as in Example 1, except that ETL-3 was used instead of Compound 2-1. The obtained measurement results are shown in Table 1. Comparative Example-5 The obtained measurement results are shown in Table 1. In the device example 1, an organic electroluminescent device was prepared and evaluated by the same method as in the example 1 except that ETL-4 was used instead of the compound 2-1. Comparative Example-6 The obtained measurement results are shown in Table 1. In the device example 1, an organic electroluminescent device was prepared and evaluated by the same method as in the example 1 except that ETL-5 was used instead of the compound 2-1. Comparative Example-7 The obtained measurement results are shown in Table 1. In the device example 1, an organic electroluminescent device was prepared and evaluated by the same method as in the example 1, except that ETL-6 was used instead of the compound 2-1.

[0193] [Table 1]

[0194] Example-6 In Example-1, except that EBL-2 was used instead of EBL-1, BD-1 was used instead of Compound 1-1, Compound 2-4 was used instead of Compound 2-1, and Liq was used instead of ytterbium, an organic electroluminescent element was prepared and evaluated by the same method as in Element Example-1. The obtained measurement results are shown in Table 2. Example-7 The obtained results are shown in Table 2. Comparative Example-2 The obtained results are shown in Table 2. Comparative Example-8 The obtained results are shown in Table 2. Comparative Example-9 The obtained results are shown in Table 2. Comparative Example-10 The obtained results are shown in Table 2. Comparative Example-11 The obtained results are shown in Table 2.

[0195] [Table 2]

[0196] According to Tables 1 and 2, the electron transport region involved in one embodiment of the present invention contains the triazine compound represented by the formula (2), the light-emitting layer involved in one embodiment of the present invention contains the boron compound represented by the formula (1) and / or the hole transport region contains the axial olefin compound represented by the formula (3), compared with the previously known structures, can provide an organic electroluminescent element that not only has excellent driving voltage characteristics and current efficiency characteristics, but also takes into account efficiency changes and small efficiency changes after continuous driving.

[0197] While the invention has been described in detail and with reference to specific embodiments, it will be apparent to one skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

[0198] It should be noted that the entire contents of the specifications, claims, drawings, and abstracts of Japanese Patent Application No. 2022-106807 and Japanese Patent Application No. 2022-106810 filed on July 1, 2022, and Japanese Patent Application No. 2023-088821 and Japanese Patent Application No. 2023-088916 filed on May 30, 2023 are cited herein and introduced as a disclosure of the specification of the present invention. Description of Reference Numerals

[0199] 1 substrate 2 Anode 3 Hole transport region 31. First hole transport layer 32. Second hole transport layer 33. Third hole transport layer 4. Luminescent layer 5 Electron transport region 51 First electron transport layer 52 Second electron transport layer 53 The third electron transport layer 6 Cathode 100 Organic electroluminescent element.

Claims

1. An organic electroluminescent element, characterized in that: have: anode; a cathode, which is opposite to the anode; A light-emitting layer disposed between the anode and the cathode; A hole transport region, which is disposed between the anode and the light-emitting layer; as well as an electron transport region disposed between the light-emitting layer and the cathode, The electron transport region contains a triazine compound represented by formula (2), The organic electroluminescent element satisfies at least one of the following conditions (i) and (ii), (i) the light-emitting layer contains a boron compound represented by formula (1); (ii) the hole transport region contains a radialene compound represented by formula (3), In formula (2), Ar 1 represents a phenyl group which may be substituted by an alkyl group having 1 to 6 carbon atoms, a naphthyl group which may be substituted by an alkyl group having 1 to 6 carbon atoms, or a biphenyl group which may be substituted by an alkyl group having 1 to 6 carbon atoms; Ar 2 represents a phenyl group which may be substituted by an alkyl group having 1 to 4 carbon atoms, a pyridyl group which may be substituted by an alkyl group having 1 to 4 carbon atoms, a phenylpyridyl group which may be substituted by an alkyl group having 1 to 4 carbon atoms, a pyridylphenyl group which may be substituted by an alkyl group having 1 to 4 carbon atoms, or a biphenyl group which may be substituted by an alkyl group having 1 to 4 carbon atoms; Ar 3 represents a phenyl group which may be substituted by an alkyl group having 1 to 4 carbon atoms, or a biphenyl group which may be substituted by an alkyl group having 1 to 4 carbon atoms, In formula (1), ring A, ring B and ring C each independently represent an aromatic hydrocarbon ring having 6 to 20 ring atoms which may have a substituent, or an aromatic heterocyclic ring having 5 to 20 ring atoms which may have a substituent, Ra, Rb, and Rc each independently represent: deuterium, cyano, an alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted amino group, an aromatic hydrocarbon group having 6 to 20 ring atoms, or a heteroaromatic group having 5 to 20 ring atoms, a, b, and c are each independently an integer of 0 to 4, Ring A and Ring B may be linked to each other via an oxygen atom, a sulfur atom, N—R′, Ra or Rb, or not. R 1 , R 2 , R' each independently represents: an alkyl group having 1 to 20 carbon atoms which may be substituted, an aromatic hydrocarbon group having 6 to 20 ring atoms which may be substituted, or a heteroaromatic group having 5 to 20 ring atoms which may be substituted; R 1 is linked to Ring A or Ring C via an oxygen atom, a sulfur atom, a substituted or unsubstituted nitrogen atom, Ra or Rc to form a ring structure, or does not form a ring structure, R 2 is linked to Ring B or Ring C via an oxygen atom, a sulfur atom, a substituted or unsubstituted nitrogen atom, Rb or Rc to form a ring structure, or does not form a ring structure, In formula (3), R 3 Each independently represents a cyano group, a halogen atom, a fluoroalkyl group, an acyl group, a sulfonyl group, a phosphoryl group, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic heterocyclic group.

2. The organic electroluminescent element according to claim 1, wherein The organic electroluminescent element satisfies the condition of (i) among the above (i) and (ii).

3. The organic electroluminescent element according to claim 1, wherein The organic electroluminescent element satisfies the condition (ii) among the above (i) and (ii).

4. The organic electroluminescent element according to claim 1, wherein The organic electroluminescent element satisfies both conditions (i) and (ii) above.

5. The organic electroluminescent element according to claim 2 or 4, wherein: In the formula (1), at least one of the rings A to C is a benzene ring which may have a substituent.

6. The organic electroluminescent element according to claim 2 or 4, wherein: In the formula (1), Ring A to Ring C are rings containing a benzene structure which may have a substituent.

7. The organic electroluminescent element according to claim 2 or 4, wherein: In formula (1), at least one of Ra, Rb and Rc is an alkyl group having 1 to 4 carbon atoms.

8. The organic electroluminescent element according to claim 2 or 4, wherein: The boron compound represented by formula (1) is selected from the following compounds, 9. The organic electroluminescent element according to claim 2 or 4, wherein: The boron compound represented by formula (1) is the compound of 1-1 above.

10. The organic electroluminescent element according to claim 3 or 4, wherein: The hole transport region at least has: a first hole transport layer; as well as The second hole transport layer is disposed between the first hole transport layer and the light emitting layer. The first hole transport layer contains a radialene compound represented by formula (3).

11. The organic electroluminescent element according to claim 3 or 4, wherein: The radialene compound represented by formula (3) is formula (3-a), In formula (3-a), R 3 each independently represents a cyano group, a halogen atom, a fluoroalkyl group, an acyl group, a sulfonyl group, a phosphoryl group, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic heterocyclic group, Ar 4 Each independently represents a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted aromatic heterocyclic group, R 3 and Ar 4 The substituents possessed by the substituted or unsubstituted aromatic hydrocarbon group and the substituted or unsubstituted aromatic heterocyclic group are each independently selected from deuterium, a cyano group, a halogen atom, a fluoroalkyl group, an acyl group, a sulfonyl group, and a phosphoryl group.

12. The organic electroluminescent element according to claim 3 or 4, wherein: The radialene compound represented by formula (3) is formula (3-b), In formula (3-b), R 31 are each independently selected from deuterium, a cyano group, a halogen atom, a fluoroalkyl group, an acyl group, a sulfonyl group and a phosphoryl group, s is an integer of 1-5 each independently.

13. The organic electroluminescent element according to claim 3 or 4, wherein: The radialene compound represented by formula (3) is the following formula 3-1, 14. The organic electroluminescent element according to claim 1, wherein: The electron transport region at least has: a first electron transport layer; as well as A second electron transport layer is disposed between the first electron transport layer and the cathode, The second electron transport layer contains a triazine compound represented by formula (2).

15. The organic electroluminescent element according to claim 1, wherein: The triazine compound represented by formula (2) is the following compound, 16. The organic electroluminescent element according to claim 14, wherein The second electron transport layer contains a compound represented by formula (2) and lithium quinolate (Liq),

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