Azine compound, material for organic electroluminescence device containing said azine compound and organic electroluminescence device

Abstract

Provided are: an azine compound useful for the production of an organic electroluminescent element capable of exhibiting excellent drive voltage, luminous efficacy, and service life; an organic electroluminescent element material containing said azine compound; and an organic electroluminescent element.　Provided are: the azine compound having a specific structure represented by formula (1); the organic electroluminescent element material containing said azine compound; and the organic electroluminescent element.

Description

[Technical field]

[0001] The present disclosure relates to an azine compound, a material for an organic electroluminescent device containing the azine compound, and an organic electroluminescent device. [Background technology]

[0002] Organic electroluminescent devices have started to be put to practical use, mainly for small mobile devices. However, to further expand their applications, it is essential to improve their performance, and materials with low driving voltage, high luminous efficiency, and long life characteristics are required.

[0003] Patent Document 1 discloses an azine compound that is a material for an organic electroluminescent device that is highly efficient and can reduce the driving voltage. Patent Document 2 discloses an azine compound having high heat resistance and high electron transport ability. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2007 / 023840 [Patent Document 2] JP 2012-82136 A Summary of the Invention [Problem to be solved by the invention]

[0005] There is a strong demand from the market for the expansion of applications and environments in which the devices can be used. The azine compounds disclosed in Patent Document 1 and Patent Document 2 do not fully satisfy the three characteristics of driving voltage, luminous efficiency, and life characteristics, and there is a demand for compounds that achieve the above three characteristics at an even higher level.

[0006] Therefore, one aspect of the present disclosure is directed to providing an azine compound that contributes to the production of an organic electroluminescent device that can exhibit excellent driving voltage characteristics, luminous efficiency characteristics, and life characteristics, and a material for an organic electroluminescent device that contains the azine compound.

[0007] Furthermore, another aspect of the present disclosure is directed to providing an organic electroluminescent device that can achieve high levels of driving voltage characteristics, luminous efficiency characteristics, and life characteristics. [Means for solving the problem]

[0008] According to one aspect of the present disclosure, there is provided an azine compound represented by formula (1):

[0009] [ka]

[0010] During the ceremony, Ar 1 represents a phenyl group, a biphenylyl group, a naphthyl group, a phenylnaphthyl group, or a naphthylphenyl group, which may be substituted by one or more substituents selected from the group consisting of a fluorine atom, a methyl group, and a cyano group; Ar 2 represents a biphenylyl group, a naphthyl group, a phenylnaphthyl group, or a naphthylphenyl group, which may be substituted by one or more substituents selected from the group consisting of a fluorine atom, a methyl group, and a cyano group; Ar 3 and Ar 4 each independently represents an aromatic group selected from (a) and (b) below: (a) a monocyclic, bicyclic or tricyclic hydrocarbon aromatic group having 6 to 18 carbon atoms, which may be substituted by one or more substituents selected from the group consisting of a fluorine atom, an alkyl group having 1 to 4 carbon atoms, and a phenyl group; (b) a heteroaromatic group having 4 to 18 carbon atoms composed of atoms selected from the group of atoms consisting of hydrogen atoms, carbon atoms, oxygen atoms, and divalent sulfur atoms, which may be substituted by one or more substituents selected from the group consisting of fluorine atoms, alkyl groups having 1 to 4 carbon atoms, and phenyl groups; n 1 represents an integer of 1, 2, or 3.

[0011] According to another aspect of the present disclosure, there is provided a material for an organic electroluminescent device, comprising the above-mentioned azine compound. According to another aspect of the present disclosure, there is provided an organic electroluminescent device including the material for an organic electroluminescent device described above. Effect of the Invention

[0012] According to one aspect of the present disclosure, it is possible to provide an azine compound that contributes to the production of an organic electroluminescent device that can exhibit excellent driving voltage characteristics, luminous efficiency characteristics, and life characteristics, and a material for an organic electroluminescent device that contains the azine compound.

[0013] According to another aspect of the present disclosure, it is possible to provide an organic electroluminescent device that can achieve high levels of driving voltage characteristics, luminous efficiency characteristics, and life characteristics. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic cross-sectional view showing an example of a layered configuration of an organic electroluminescent device according to one embodiment of the present disclosure. [Diagram 2] FIG. 2 is a schematic cross-sectional view showing another example of a laminate configuration of an organic electroluminescent device according to an embodiment of the present disclosure (configuration of device example 1). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The azine compound according to one embodiment of the present disclosure will be described in detail below.

[0016] <Azine compounds> An azine compound according to one embodiment of the present disclosure is an azine compound represented by formula (1):

[0017] [ka]

[0018] During the ceremony, Ar 1 represents a phenyl group, a biphenylyl group, a naphthyl group, a phenylnaphthyl group, or a naphthylphenyl group, which may be substituted by one or more substituents selected from the group consisting of a fluorine atom, a methyl group, and a cyano group; Ar 2 represents a biphenylyl group, a naphthyl group, a phenylnaphthyl group, or a naphthylphenyl group, which may be substituted by one or more substituents selected from the group consisting of a fluorine atom, a methyl group, and a cyano group; Ar 3 and Ar 4 each independently represents an aromatic group selected from (a) and (b) below: (a) a monocyclic, bicyclic or tricyclic hydrocarbon aromatic group having 6 to 18 carbon atoms, which may be substituted by one or more substituents selected from the group consisting of a fluorine atom, an alkyl group having 1 to 4 carbon atoms, and a phenyl group; (b) a heteroaromatic group having 4 to 18 carbon atoms composed of atoms selected from the group of atoms consisting of hydrogen atoms, carbon atoms, oxygen atoms, and divalent sulfur atoms, which may be substituted by one or more substituents selected from the group consisting of fluorine atoms, alkyl groups having 1 to 4 carbon atoms, and phenyl groups; n 1 represents an integer of 1, 2, or 3.

[0019] Hereinafter, the azine compound represented by formula (1) may be referred to as azine compound (1). The definitions of the substituents in the azine compound (1) and preferred specific examples thereof are as follows, but the present invention is not limited to these.

[0020] [Ar 1About Ar 1 represents a phenyl group, a biphenylyl group, a naphthyl group, a phenylnaphthyl group, or a naphthylphenyl group, which may be substituted with one or more groups selected from the group consisting of a fluorine atom, a methyl group, and a cyano group. 1 is preferably a phenyl group or a biphenylyl group.

[0021] [Ar 2 About Ar 2 represents a biphenylyl group, a naphthyl group, a phenylnaphthyl group, or a naphthylphenyl group, which may be substituted with one or more groups selected from the group consisting of a fluorine atom, a methyl group, and a cyano group. 2 is preferably a biphenylyl group.

[0022] [Ar 3 and Ar 4 About Ar 3 and Ar 4 each independently represents an aromatic group selected from the following (a) and (b): (a) A monocyclic, bicyclic or tricyclic hydrocarbon aromatic group having 6 to 18 carbon atoms which may be substituted with one or more substituents selected from the group consisting of a fluorine atom, an alkyl group having 1 to 4 carbon atoms, and a phenyl group. (b) A heteroaromatic group having 4 to 18 carbon atoms composed of atoms selected from the group of atoms consisting of hydrogen atoms, carbon atoms, oxygen atoms, and divalent sulfur atoms, which may be substituted by one or more substituents selected from the group consisting of fluorine atoms, alkyl groups having 1 to 4 carbon atoms, and phenyl groups.

[0023] Ar 3 and Ar 4 are each independently an aromatic group selected from the following (a') and (b'): (a') A monocyclic, bicyclic or tricyclic hydrocarbon aromatic group having 6 to 18 carbon atoms which may be substituted with one or more groups selected from the group consisting of methyl groups and phenyl groups. (b') A heteroaromatic group having 4 to 18 carbon atoms and composed of atoms selected from the group of atoms consisting of hydrogen atoms, carbon atoms, oxygen atoms, and divalent sulfur atoms, which may be substituted with one or more groups selected from the group consisting of methyl groups and phenyl groups.

[0024] Ar 3 In terms of facilitating the synthesis of the azine compound (1), the aromatic group represented by the formula (I) may be substituted with one or more substituents selected from the group consisting of a fluorine atom, an alkyl group having 1 to 4 carbon atoms, and a phenyl group. Aromatic hydrocarbon groups such as phenyl, naphthyl, fluorenyl, anthryl and phenanthrenyl groups; and heteroaromatic groups such as a benzothiophenyl group, a benzofuranyl group, a thieno[3,2-b]thiophenyl group, a furo[3,2-b]furanyl group, a dibenzofuranyl group, and a dibenzothiophenyl group;

[0025] The azine compound (1) is easy to synthesize, and Ar 3 is preferably a phenyl group, a biphenylyl group, a naphthyl group, a fluorenyl group, an anthryl group, a phenanthrenyl group, a dibenzofuranyl group or a dibenzothiophenyl group, and more preferably a phenyl group or a biphenylyl group.

[0026] Ar 4 The aromatic group represented by the formula (I) may be substituted with one or more substituents selected from the group consisting of a fluorine atom, an alkyl group having 1 to 4 carbon atoms, and a phenyl group. Aromatic hydrocarbon groups such as phenyl, naphthyl, fluorenyl, anthryl and phenanthrenyl groups; and heteroaromatic groups such as a benzothiophenyl group, a benzofuranyl group, a thieno[3,2-b]thiophenyl group, a furo[3,2-b]furanyl group, a dibenzofuranyl group, and a dibenzothiophenyl group;

[0027] The azine compound (1) is easy to synthesize, and Ar 4 is preferably a phenyl group, a naphthyl group, a fluorenyl group, an anthryl group, a phenanthrenyl group, a dibenzofuranyl group or a dibenzothiophenyl group, and more preferably a phenyl group or a naphthyl group.

[0028] Ar 3 and Ar 4 More preferably, both of them are phenyl groups.

[0029] n 1 represents an integer of 1, 2, or 3. In terms of ease of synthesis of the azine compound (1), n 1 is preferably 1 or 2.

[0030] Specific examples of the azine compound (1) are shown below, but the present invention is not limited to these.

[0031] [ka]

[0032] [ka]

[0033] [ka]

[0034] [ka]

[0035] [ka]

[0036] [ka]

[0037] The azine compound (1) can be produced by appropriately combining known reactions (such as Suzuki-Miyaura cross-coupling reaction) that are commonly used by those skilled in the art as a method for synthesizing aromatic compounds. For example, the azine compound (1) can be produced by the methods shown in the following synthetic pathways (i) to (iv).

[0038] [ka]

[0039] [ka]

[0040] [ka]

[0041] [ka]

[0042] In the formula, Ar 1 , Ar 2 , Ar 3 , Ar 4 and n 1 are the Ar of the above-mentioned azine compound (1), 1 , Ar 2 , Ar 3 , Ar 4 and n 1 X 1 , X 2 , X 3 , X 4 and X 5 R each independently represents a halogen atom or a trifluoromethanesulfonyloxy group. 1 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group. B(OR 1 )2 of 2 R 1 may be the same or different. Also, two R1 may be joined together to form a ring containing the oxygen atom and the boron atom.

[0043] X 1 , X 2 , X 3 , X 4 and X 5 Examples of the halogen atom represented by the formula (I) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. In view of the low cost of the raw materials for the triazine compound (1), a chlorine atom or a bromine atom is preferred.

[0044] B(OR) in the boron compounds represented by formulas (3), (4), (8) and (10) 1 )2 is not particularly limited, but examples thereof include B(OH)2, B(OMe)2, and B(O i Examples include B(Pr), B(OBu), and B(OPh). Note that Me is a methyl group. i Pr is an isopropyl group, Bu is a butyl group, and Ph is a phenyl group. 1 When these are combined to form a ring containing an oxygen atom and a boron atom, B(OR 1 Examples of 2 include, but are not limited to, the following groups (I) to (VI), of which the group (II) is preferred in terms of good yield.

[0045] [ka]

[0046] The coupling reactions in the synthetic routes (i) to (iv) are methods in which an aryl halide compound represented by formula (2), (5), (6), (7), (9), (11) or (12) is reacted with a boron compound represented by formula (3), (4), (8) or (10) in the presence of a palladium catalyst and a base, and general reaction conditions for the Suzuki-Miyaura reaction can be applied.

[0047] The triazine compound (2) used in the coupling reaction can be produced, for example, according to the method disclosed in JP-A-2019 / 131500 or JP-A-2008 / 130840. The triazine compound (4) used in the coupling reaction can be produced, for example, according to the method disclosed in WO 2014 / 208829 or WO 2014 / 171541.

[0048] The boron compound used in the coupling reaction can be produced, for example, according to the method disclosed in The Journal of Organic Chemistry, Vol. 60, p. 7508, 1995 or The Journal of Organic Chemistry, Vol. 65, p. 164, 2000. Commercially available products may also be used.

[0049] The aryl halide used in the coupling reaction can be produced, for example, according to Journal of the American Chemical Society, vol. 74, p. 6289, 1952, or Synlett, p. 808, 2002. Commercially available products may also be used. There is no particular limit to the molar equivalent of the aryl halide used, but it is preferable to use 0.5 to 3.0 molar equivalents relative to the boron compound in terms of good reaction yield.

[0050] The palladium catalyst used in the above-mentioned coupling reaction is not particularly limited, but specific examples include palladium salts such as palladium chloride, palladium acetate, palladium trifluoroacetate, and palladium nitrate. In addition, π-allylpalladium chloride dimer, palladium acetylacetonate, tris(dibenzylideneacetone)dipalladium, bis(dibenzylideneacetone)palladium, dichlorobis(acetonitrile)palladium, and dichlorobis(benzonitrile)palladium complexes, and palladium complexes having tertiary phosphines as ligands, such as dichlorobis(triphenylphosphine)palladium, tetrakis(triphenylphosphine)palladium, dichloro(1,1'-bis(diphenylphosphino)ferrocene)palladium, bis(tri-tert-butylphosphine)palladium, bis(tricyclohexylphosphine)palladium, and dichlorobis(tricyclohexylphosphine)palladium, can be exemplified, and these can also be prepared in the reaction system by adding a tertiary phosphine to a palladium salt or complex. Examples of tertiary phosphines that can be used in this case include triphenylphosphine, trimethylphosphine, tributylphosphine, tri(tert-butyl)phosphine, tricyclohexylphosphine, tert-butyldiphenylphosphine, 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene, 2-(diphenylphosphino)-2'-(N,N-dimethylamino)biphenyl, 2-(di-tert-butylphosphino)biphenyl, 2-(dicyclohexylphosphino)biphenyl, bis(diphenylphosphine), Examples of the 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl phosphine include 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl phosphine, 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl phosphine, 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl phosphine, 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl phosphine, and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl phosphine.

[0051] Among them, a palladium complex having a tertiary phosphine as a ligand is preferred in terms of good yield, and a palladium complex having 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl as a ligand is more preferred. The molar ratio of the tertiary phosphine to the palladium salt or complex compound is preferably in the range of 1:10 to 10:1, and more preferably in the range of 1:2 to 3:1 in terms of good yield. There is no restriction on the amount of the palladium catalyst used in the above-mentioned coupling reaction, but in terms of good yield, the molar equivalent of the palladium catalyst is preferably in the range of 0.005 to 0.5 molar equivalent to the boron compound.

[0052] The base used in the above-mentioned coupling reaction is not particularly limited, but examples thereof include metal hydroxide salts such as sodium hydroxide, potassium hydroxide, and calcium hydroxide, metal carbonate salts such as sodium carbonate, potassium carbonate, lithium carbonate, and cesium carbonate, metal acetate salts such as potassium acetate and sodium acetate, metal phosphate salts such as potassium phosphate and sodium phosphate, metal fluoride salts such as sodium fluoride, potassium fluoride, and cesium fluoride, and metal alkoxides such as sodium methoxide, potassium methoxide, sodium ethoxide, potassium isopropyl oxide, and potassium tert-butoxide, etc. Among them, metal carbonates and metal phosphates are preferred in terms of good reaction yield, and potassium carbonate or potassium phosphate is more preferred. There is no particular limit to the amount of base used, but in terms of good reaction yield, the molar ratio of the base to the boron compound is preferably in the range of 1:2 to 10:1, and more preferably in the range of 1:1 to 4:1.

[0053] The aforementioned coupling reaction can be carried out in a solvent. Solvents that can be used in the above-mentioned coupling reaction include water, ethers such as diisopropyl ether, dibutyl ether, cyclopentyl methyl ether (CPME), tetrahydrofuran (THF), 2-methyltetrahydrofuran, 1,4-dioxane, and dimethoxyethane, aromatic hydrocarbons such as benzene, toluene, xylene, mesitylene, and tetralin, carbonates such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and 4-fluoroethylene carbonate, ethyl acetate, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate, and γ-lanthanide. Examples of the solvent include esters such as methacrylate, amides such as N,N-dimethylformamide (DMF), dimethylacetamide (DMAc), and N-methylpyrrolidone (NMP), ureas such as N,N,N',N'-tetramethylurea (TMU), N,N'-dimethylpropyleneurea (DMPU), and alcohols such as dimethylsulfoxide (DMSO), methanol, ethanol, isopropyl alcohol, butanol, octanol, benzyl alcohol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, and 2,2,2-trifluoroethanol, and may be mixed in any ratio. There is no particular limit to the amount of the solvent used. Among these, water, ethers, amides, alcohols, or mixed solvents thereof are preferred in terms of good reaction yield, and a mixed solvent of THF and water is more preferred.

[0054] The above-mentioned coupling reaction can be carried out at a temperature appropriately selected from 0° C. to 200° C., and is preferably carried out at a temperature appropriately selected from 100° C. to 160° C. in terms of good reaction yield.

[0055] The azine compound (1) can be obtained by carrying out a normal treatment after the completion of the above-mentioned coupling reaction, and may be purified, if necessary, by recrystallization, column chromatography, sublimation, preparative HPLC, or the like.

[0056] <Materials for organic electroluminescence devices> The azine compound (1) is useful as a material for organic electroluminescence devices. The azine compound (1) can be used, for example, as an electron transport material for organic electroluminescence devices. By using a material for organic electroluminescence devices containing the azine compound (1), it is possible to prepare an organic electroluminescence device that exhibits high luminous efficiency and long life characteristics and can be used for various purposes or under various environments.

[0057] <Organic electroluminescent device> An organic electroluminescent device containing an azine compound (1) (hereinafter, sometimes simply referred to as an organic electroluminescent device) will be described below.

[0058] The organic electroluminescent device according to one aspect of the present invention contains an azine compound (1).

[0059] The configuration of the organic electroluminescent device is not particularly limited, but examples thereof include the following configurations (i) to (v). (i): Anode / Emitting layer / Cathode (ii): anode / hole transport layer / light emitting layer / cathode (iii): anode / light-emitting layer / electron transport layer / cathode (iv): anode / hole transport layer / light emitting layer / electron transport layer / cathode (v): anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode

[0060] The azine compound (1) may be contained in any of the above layers. However, in terms of excellent light-emitting properties of the organic electroluminescent device, it is preferable that the azine compound (1) is contained in one or more layers selected from the group consisting of the light-emitting layer and the layer between the light-emitting layer and the cathode.

[0061] Therefore, in the case of the above configurations (i) to (v), the azine compound (1) is preferably contained in one or more layers selected from the group consisting of a light-emitting layer, an electron-transporting layer, and an electron-injecting layer.

[0062] Hereinafter, an organic electroluminescent device according to one embodiment of the present invention will be described in more detail with reference to FIG. 1, taking the above configuration (v) as an example.

[0063] 1 has a so-called bottom-emission type element configuration, the organic electroluminescent element according to one embodiment of the present invention is not limited to the bottom-emission type element configuration. That is, the organic electroluminescent element according to one embodiment of the present invention may have another known element configuration, such as a top-emission type.

[0064] FIG. 1 is a schematic cross-sectional view showing an example of a layered structure of an organic electroluminescent device containing an azine compound according to one embodiment of the present invention.

[0065] The organic electroluminescent device 100 includes a substrate 1, an anode 2, a hole injection layer 3, a hole transport layer 4, an emitting layer 5, an electron transport layer 6, an electron injection layer 7, and a cathode 8, in this order. However, some of these layers may be omitted, or other layers may be added. For example, a hole blocking layer may be provided between the emitting layer 5 and the electron transport layer 6, or the hole injection layer 3 may be omitted and the hole transport layer 4 may be provided directly on the anode 2.

[0066] Alternatively, a single layer having the functions of multiple layers, such as an electron injection / transport layer having both the functions of an electron injection layer and an electron transport layer, may be provided instead of the multiple layers. Furthermore, the single-layer hole transport layer 4 and the single-layer electron transport layer 6 may each be made up of multiple layers. <<Layer Containing Azine Compound (1)>>

[0067] 1, the organic electroluminescent device 100 contains an azine compound (1) in one or more layers selected from the group consisting of the light-emitting layer 5, the electron transport layer 6, and the electron injection layer 7. It is preferable that the electron transport layer 6 contains the azine compound (1). The azine compound (1) may be contained in multiple layers of the organic electroluminescent device.

[0068] The organic electroluminescent device 100 in which the electron transport layer 6 contains the azine compound (1) will be described below.

[0069] [Substrate 1] The substrate 1 is not particularly limited as long as it is a commonly used substrate, and examples thereof include a glass plate, a quartz plate, a plastic plate, a plastic film, etc. Among these, a glass plate, a quartz plate, and a light-transmitting plastic film are preferable.

[0070] 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), etc.

[0071] In addition, in the case of a configuration in which light is extracted from the substrate 1 side, the substrate 1 is transparent to the wavelength of the emitted light.

[0072] [Anode 2] An anode 2 is provided on the substrate 1 (on the hole injection layer 3 side).

[0073] Examples of the anode material include metals, alloys, electrically conductive compounds, and mixtures thereof, each having a large work function (e.g., 4 eV or more).Specific examples of the anode material include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO2, and ZnO.

[0074] In the case of an organic electroluminescent device in which light is extracted through the anode, the anode is formed of a conductive transparent material that is transparent or substantially transparent to the emitted light.

[0075] [Hole injection layer 3, hole transport layer 4] Between the anode 2 and the light-emitting layer 5, a hole injection layer 3 and a hole transport layer 4 are provided in this order from the anode 2 side.

[0076] The hole injection layer 3 and the hole transport layer 4 have the function of transporting holes injected from the anode to the light-emitting layer. By interposing the hole injection layer 3 and the hole transport layer 4 between the anode 2 and the light-emitting layer 5, a large number of holes are injected into the light-emitting layer 5 with a lower electric field.

[0077] The hole injection layer 3 and the hole transport layer 4 also function as electron barrier layers. That is, the electrons injected from the cathode 8 and transported from the electron injection layer 7 and / or the electron transport layer 6 to the light emitting layer 5 are prevented from leaking to the hole injection layer 3 and / or the hole transport layer 4 by the electron barrier present at the interface between the light emitting layer 5 and the hole injection layer 3 and / or the hole transport layer 4. As a result, the electrons are accumulated at the interface in the light emitting layer 5, which brings about effects such as improved light emitting efficiency, and an organic electroluminescent device with excellent light emitting performance is obtained.

[0078] The material for the hole injection layer 3 and the hole transport layer 4 has at least one of hole injection property, hole transport property, and electron barrier property. The material for the hole injection layer 3 and the hole transport layer 4 may be either an organic compound or an inorganic substance.

[0079] Specific examples of materials for the hole injection layer 3 and the hole transport layer 4 include triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane 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-based copolymers, conductive polymer oligomers (particularly thiophene oligomers), porphyrin compounds, aromatic tertiary amine compounds, and styrylamine compounds.

[0080] Among these, porphyrin compounds, aromatic tertiary amine compounds, and styrylamine compounds are preferred in terms of good performance of the organic electroluminescent device, and aromatic tertiary amine compounds are particularly preferred.

[0081] Specific examples of aromatic tertiary amine compounds and styrylamine compounds include N,N,N',N'-tetraphenyl-4,4'-diaminophenyl, N,N'-diphenyl-N,N'-bis(m-tolyl)-[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'- Examples of such compounds include di(4-methoxyphenyl)-4,4'-diaminobiphenyl, N,N,N',N'-tetraphenyl-4,4'-diaminodiphenyl ether, 4,4'-bis(diphenylamino)quadriphenyl, N,N,N-tri(p-tolyl)amine, 4-(di-p-tolylamino)-4'-[4-(di-p-tolylamino)styryl]stilbene, 4-N,N-diphenylamino-(2-diphenylvinyl)benzene, 3-methoxy-4'-N,N-diphenylaminostilbene, N-phenylcarbazole, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPD), and 4,4',4''-tris[N-(m-tolyl)-N-phenylamino]triphenylamine (MTDATA).

[0082] Furthermore, examples of the material for the hole injection layer 3 and the hole transport layer 4 include inorganic compounds such as p-type Si and p-type SiC.

[0083] The hole injection layer 3 and the hole transport layer 4 may have a single structure made of one or more materials, or may have a laminate structure made of multiple layers of the same or different compositions.

[0084] [Light-emitting layer 5] Between the hole transport layer 4 and the electron transport layer 6, the light emitting layer 5 is provided.

[0085] Examples of the material of the light-emitting layer 5, that is, the light-emitting material, include phosphorescent materials, fluorescent materials, and thermally activated delayed fluorescent materials. In the light-emitting layer 5, electron-hole pairs are recombined, resulting in light emission.

[0086] The light-emitting layer 5 may consist of a single small molecule or single polymeric material, but more commonly consists of a host material doped with a guest compound. Emission comes primarily from the dopant and can be of any color.

[0087] Examples of the host material include compounds having a biphenylyl group, a fluorenyl group, a triphenylsilyl group, a carbazole group, a pyrenyl group, and an anthryl group. More specifically, examples of the compound include DPVBi (4,4'-bis(2,2-diphenylvinyl)-1,1'-biphenyl), BCzVBi (4,4'-bis(9-ethyl-3-carbazovinylene)-1,1'-biphenyl), TBADN (2-tertiarybutyl-9,10-di(2-naphthyl)anthracene), ADN (9,10-di(2-naphthyl)anthracene), CBP (4,4'-bis(carbazol-9-yl)biphenyl), CDBP (4,4'-bis(carbazol-9-yl)-2,2'-dimethylbiphenyl), 2-(9-phenylcarbazol-3-yl)-9-[4-(4-phenylphenylquinazolin-2-yl)carbazole, 9,10-bis(biphenyl)anthracene, and the like.

[0088] Examples of the fluorescent dopant include anthracene, pyrene, tetracene, xanthene, perylene, rubrene, coumarin, rhodamine, quinacridone, dicyanomethylenepyran compound, thiopyran compound, polymethine compound, pyrylium, thiapyrylium compound, fluorene derivative, periflanthene derivative, indenoperylene derivative, bis(azinyl)amine boron compound, bis(azinyl)methane compound, carbostyril compound, boron compound, cyclic amine compound, etc. The fluorescent dopant may be a combination of two or more selected from these.

[0089] Phosphorescent dopants include, for example, complexes of metals such as iridium, platinum, palladium, and osmium.

[0090] Specific examples of fluorescent dopants and phosphorescent dopants include Alq3 (tris(8-hydroxyquinoline)aluminum), DPAVBi (4,4'-bis[4-(di-p-tolylamino)styryl]biphenyl), perylene, bis[2-(4-n-hexylphenyl)quinoline](acetylacetonate)iridium(III), Ir(PPy)3 (tris(2-phenylpyridine)iridium(III)), FIrPic (bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl)iridium(III))), and the like.

[0091] Moreover, the light-emitting material is not limited to being contained only in the light-emitting layer 5. For example, the light-emitting material may be contained in a layer adjacent to the light-emitting layer 5 (the hole transport layer 4 or the electron transport layer 6). This can further increase the luminous efficiency of the organic electroluminescent device 100.

[0092] The light-emitting layer 5 may have a single layer structure made of one or more materials, or may have a laminate structure made of multiple layers of the same composition or different compositions.

[0093] [Electron transport layer 6] Between the light-emitting layer 5 and the electron injection layer 7, an electron transport layer 6 is provided.

[0094] The electron transport layer 6 has a function of transporting electrons injected from the cathode 8 to the light-emitting layer. By interposing the electron transport layer 7 between the cathode 8 and the light-emitting layer 5, electrons are injected into the light-emitting layer 5 at a lower electric field.

[0095] As described above, the electron transport layer 6 preferably contains the azine compound (1). The electron transport layer 6 may further contain, in addition to the azine compound (1), one or more types selected from conventionally known electron transport materials.

[0096] In addition, when the azine compound (1) is not contained in the electron transport layer 6 but is contained in another layer, one or more types selected from conventionally known electron transport materials can be used as the electron transport material constituting the electron transport layer 6.

[0097] Examples of conventionally known electron transporting materials include alkali metal compounds, alkaline earth metal compounds, transition metal compounds, zinc group element compounds, earth metal compounds, etc. Examples of alkali metal compounds, alkaline earth metal compounds, transition metal compounds, zinc group element compounds, earth metal compounds, etc. include 8-hydroxyquinolinato lithium (Liq), bis(8-hydroxyquinolinato) zinc, bis(8-hydroxyquinolinato) copper, bis(8-hydroxyquinolinato) manganese, tris(8-hydroxyquinolinato) aluminum, tris(2-methyl-8-hydroxyquinolinato) aluminum, tris(8-hydroxyquinolinato) bis(2-methyl-8-quinolinato)gallium, bis(10-hydroxybenzo[h]quinolinato)beryllium, bis(10-hydroxybenzo[h]quinolinato)zinc, bis(2-methyl-8-quinolinato)chlorogallium, bis(2-methyl-8-quinolinato)(o-cresolate)gallium, bis(2-methyl-8-quinolinato)-1-naphtholatealuminum, and bis(2-methyl-8-quinolinato)-2-naphtholategallium are examples of chelate-type aryloxides.

[0098] The electron transport layer 6 may have a single layer structure made of one or more materials, or may have a laminate structure made of multiple layers of the same composition or different compositions.

[0099] In the organic electroluminescent device 100, an electron injection layer 7 may be provided for the purpose of improving the electron injection property and improving the device characteristics (for example, luminous efficiency, low-voltage driving, or high durability).

[0100] [Electron injection layer 7] An electron injection layer 7 is provided between the electron transport layer 6 and the cathode 8. The electron injection layer 7 has a function of transporting electrons injected from the cathode to the light-emitting layer 5. By providing the electron injection layer between the cathode 8 and the light-emitting layer 5, electrons are injected into the light-emitting layer 5 at a lower electric field.

[0101] Examples of materials for the electron injection layer 7 include organic compounds such as fluorenone, anthraquinodimethane, diphenoquinone, thiopyran dioxide, oxazole, oxadiazole, triazole, imidazole, perylene tetracarboxylic acid, fluorenylidenemethane, anthraquinodimethane, and anthrone.

[0102] Examples of materials for the electron injection layer 7 include inorganic compounds such as various oxides, fluorides, nitrides, and oxynitrides, such as SiO, AlO, SiN, SiON, AlON, GeO, LiO, LiON, TiO, TiON, TaO, TaON, TaN, LiF, C, and Yb.

[0103] [Cathode 8] A cathode 8 is provided on the electron injection layer 7. In the case of an organic electroluminescence element configured so that only light emitted through the anode 8 is extracted, the cathode 8 can be formed from any conductive material.

[0104] Examples of materials for the cathode 8 include metals with a small work function (hereinafter also referred to as electron injecting metals), alloys, electrically conductive compounds, and mixtures thereof. Here, the metals with a small work function are, for example, metals with a work function of 4 eV or less.

[0105] Specific examples of materials for the cathode 8 include sodium, sodium-potassium alloy, magnesium, lithium, a magnesium / copper mixture, a magnesium / silver mixture, a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (Al2O3) mixture, indium, a lithium / aluminum mixture, and rare earth metals.

[0106] Among these, from the standpoint of electron injectability and durability against oxidation, etc., mixtures of an electron injecting metal and a second metal which has a larger and more stable work function than the electron injecting metal, such as a magnesium / silver mixture, a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (Al2O3) mixture, and a lithium / aluminum mixture, are preferred.

[0107] [How each layer is formed] Each layer except for the electrodes (anode, cathode) described above can be formed into a thin film by a known method such as vacuum deposition, spin coating, casting, LB (Langmuir-Blodgett) method, etc. The material of each layer may be used alone or, if necessary, together with a material such as a binder resin or a solvent.

[0108] There are no particular limitations on the film thickness of each layer thus formed, and it can be appropriately selected depending on the situation, but it is usually in the range of 5 nm to 5 μm.

[0109] The anode 1 and the cathode 8 can be formed by forming a thin film of an electrode material by a method such as vapor deposition or sputtering. A pattern may be formed through a mask of a desired shape during vapor deposition or sputtering, or a pattern of a desired shape may be formed by photolithography or the like after forming a thin film by vapor deposition or sputtering.

[0110] The film thickness of the anode 1 and the cathode 8 is preferably 1 μm or less, and more preferably 10 nm or more and 200 nm or less.

[0111] In addition, when forming a layer containing the azine compound (1), it may be used in combination with the above-mentioned conventionally known electron transporting material. Thus, for example, the azine compound (1) and the conventionally known electron transporting material may be co-deposited, or a layer of the conventionally known electron transporting material may be laminated on the layer of the azine compound (1).

[0112] The organic electroluminescent device according to one embodiment of the present invention may be used as a kind of lamp such as a light source for illumination or exposure, or as a projection device that projects an image onto a screen or the like, or as a display device (display) that directly displays still images or moving images.

[0113] When the organic electroluminescent element according to one embodiment of the present invention is used as a display device for playing moving images, the driving method may be a simple matrix (passive matrix) method or an active matrix method. In addition, by using two or more kinds of organic electroluminescent elements having different emission colors, a full-color display device can be produced.

[0114] When the azine compound (1) is used in an electron transport layer, it is possible to provide an organic electroluminescent device which is significantly superior in driving voltage and luminous efficiency to conventionally known azine compounds.

[0115] Therefore, it is expected to have the effect of improving the driving stability and luminous efficiency of the organic electroluminescence device, etc. Furthermore, because of its characteristic skeleton, the azine compound (1) has high chemical stability and can contribute to extending the life of the organic electroluminescence device.

[0116] The azine compound (1) can be used as an electron transport layer of an organic electroluminescent device to provide an azine compound capable of achieving low-voltage operation, high efficiency, and long life of the device at a high level. Furthermore, an organic electroluminescent device that uses the azine compound (1) and can achieve low-voltage operation, high efficiency, and long life can be provided. EXAMPLES

[0117] The present invention will be described in more detail below based on examples, but the present invention should not be construed as being limited to these examples.

[0118] [ 1 H-NMR measurement] 1H-NMR spectra were measured using a Bruker ASCEND 400 (400 MHz; manufactured by Bruker). 1 H-NMR spectra were measured using deuterated chloroform (CDCl3) as the measurement solvent and tetramethylsilane (TMS) as the internal standard. Commercially available reagents were used.

[0119] [DSC measurement (glass transition temperature, crystallization temperature, melting point)] The glass transition temperature, crystallization temperature and melting point were measured using a DSC7020 (product name, manufactured by Hitachi High-Tech Science Corporation).

[0120] The DSC measurement conditions are as follows. The measurement was performed under a nitrogen atmosphere (flow rate 50 ml / min). The first heating, first cooling, and second heating were performed in that order, and the glass transition temperature, crystallization temperature, and melting point during the second heating were taken as the glass transition temperature, crystallization temperature, and melting point of the sample, respectively. Sample size: 5-10mg Measurement conditions: <First Heating> Heating rate: 15℃ / min Measurement temperature range: 30℃~360℃ <First cooling> Rapid cooling with dry ice <Second heating> Heating rate: 5℃ / min Measurement temperature range: 30℃~360℃

[0121] [Luminescence property measurement] The light-emitting characteristics of the organic electroluminescent device were evaluated by applying a direct current to the fabricated device in a 25° C. environment using a luminance meter BM-9 (product name, manufactured by Topcon Technohouse Corporation).

[0122] (Synthesis Example 1) [ka]

[0123] Under an argon atmosphere, 2,4-bis(4-biphenylyl)-6-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl]-1,3,5-triazine (12.0 g, 21 mmol), 1-bromo-3,4-dichlorobenzene (5.63 g, 25 mmol) and tetrakis(triphenylphosphine)palladium (2.37 g, 2.1 mmol) were suspended in THF (200 mL). 2M potassium carbonate aqueous solution (38 mL, 76 mmol) was added to this suspension and stirred at 80 ° C for 25 hours. After cooling to room temperature, water and methanol were added and the precipitate was collected by filtration. The collected material was suspended in toluene (700 mL), heated to 110 ° C, activated carbon was added and stirred, and then filtered through Celite. The filtrate was concentrated and then purified by recrystallization from toluene to obtain 2,4-bis(4-biphenylyl)-6-(3',4'-dichlorobiphenyl-4-yl)-1,3,5-triazine (9.90 g, yield 80%). 1 H-NMR(400MHz,CDCl3)δ(ppm):8.87(d,J=8.6Hz,2H),8.86(d,J=8.5Hz,4H),7.83(brd,J=8.5Hz,4H),7.79(d ,J=1.9Hz,1H),7.76(brd,J=8.5Hz,2H),7.73(brd,J=8.5Hz,4H),7.58-7.50(m,6H),7.43(brt,J=7.3Hz,2H).

[0124] (Synthesis Example 1: Synthesis of 1-1) [ka]

[0125] Under an argon atmosphere, 2,4-bis(4-biphenylyl)-6-[3',4'-dichlorobiphenyl-4-yl]-1,3,5-triazine (9.90g, 16mmol), phenylboronic acid (7.98g, 65mmol), palladium acetate (373mg, 1.7mmol) and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (1.56g, 3.3mmol) were suspended in THF (200mL). 2M potassium phosphate aqueous solution (38mL, 76mmol) was added to this suspension and stirred at 80℃ for 18.5 hours. After cooling to room temperature, water and methanol were added and the precipitated solid was filtered. The filtered product was suspended in toluene (400mL), heated to 110℃, activated carbon was added and stirred, and then filtered through Celite. The filtrate was concentrated and then purified by recrystallization from toluene to obtain 2,4-bis(4-biphenylyl)-6-[4'-phenyl-(1,1':3',1''-terphenyl-4-yl)]-1,3,5-triazine (1-1) (7.10 g, yield 63%). 1 H-NMR(400MHz,CDCl3)δ(ppm):8.87(d,J=8.3Hz,2H),8.88(d,J=8.3Hz,4H),7.90(d,J=8.3Hz,2H),7.83(d,J=8.3Hz,4H),7.81-7.76 (m,2H),7.73(brd,J=7.7Hz,4H),7.58(d,J=7.7Hz,1H),7.51(brdd,J=7.7,7.5Hz,4H),7.41(brd,J=7.5Hz,2H),7.32-7.18(m,10H).

[0126] The structure of compound 1-1 is 1 The glass transition temperature was 120° C. as determined by 1 H-NMR spectroscopy.

[0127] (Synthesis Example 2) [ka]

[0128] Under an argon atmosphere, 2,4-bis(4-biphenylyl)-6-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl]-1,3,5-triazine (5.05 g, 8.6 mmol), 1-bromo-2,4-dichlorobenzene (2.38 g, 11 mmol) and tetrakis(triphenylphosphine)palladium (505 mg, 0.44 mmol) were suspended in THF (85 mL). 2M potassium carbonate aqueous solution (16 mL, 32 mmol) was added to this suspension and stirred at 80°C for 22 hours. After cooling to room temperature, water and methanol were added and the precipitated solid was collected by filtration. The collected material was suspended in toluene (180 mL) and heated to 110°C and stirred. After cooling to room temperature, the precipitated solid was collected by filtration to obtain 2,4-bis(4-biphenylyl)-6-(2',4'-dichlorobiphenyl-4-yl)-1,3,5-triazine (4.5 g, yield 86%). 1 H-NMR(400MHz,CDCl3)δ(ppm):8.88(d,J=8.6Hz,4H),8.88(d,J=8.5Hz,2H),7.83(ddd,J=8.6,1.88,1.84Hz,4H),7.73(brd,J=8.4Hz, 4H),7.65(ddd,J=8.5,1.84,1.76Hz,2H),7.56-7.55(m,1H),7.52(dd,J=7.8,7.2Hz,4H),7.42(brt,J=7.3Hz,2H),7.40-7.35(m,2H).

[0129] (Synthesis Example 2: Synthesis of 1-25) [ka]

[0130] Under an argon atmosphere, 2,4-bis(4-biphenylyl)-6-(2',4'-dichlorobiphenyl-4-yl)-1,3,5-triazine (4.49g, 7.4mmol), phenylboronic acid (3.63g, 30mmol), palladium acetate (86.9mg, 0.39mmol) and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (0.36g, 0.76mmol) were suspended in THF (150mL). 2M-potassium phosphate aqueous solution (45mL, 90mmol) was added to this suspension and stirred at 80°C for 15 hours. After cooling to room temperature, water and methanol were added and the precipitated solid was filtered. The filtered product was suspended in toluene (300mL), heated to 110°C, activated carbon was added and stirred, and then filtered through Celite. The filtrate was concentrated and then purified by recrystallization from toluene to obtain 2,4-bis(4-biphenylyl)-6-[4'-phenyl-(1,1':2',1''-terphenyl-4-yl)]-1,3,5-triazine (1-25) (3.1 g, yield 60%). 1 H-NMR(400MHz,CDCl3)δ(ppm):8.84(brd,J=8.5Hz,4H),8.69(brd,J=8.4Hz,2H),7.81(brd,J=8.5Hz,4H) ,7.73-7.71(m,8H),7.61(dd,J=8.4,1.1Hz,1H),7.52-7.47(m,6H),7.44-7.38(m,5H),7.29-7.27(m,5H).

[0131] The structure of compound 1-25 is 1 The glass transition temperature was 129° C. as determined by 1 H-NMR spectroscopy.

[0132] (Synthesis Example 3: Synthesis of 1-37) [ka]

[0133] Under an argon atmosphere, 2-(biphenyl-4-yl)-4-phenyl-6-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-1,3,5-triazine (2.80g, 5.7mmol), 3-(naphthalene-1-yl)-4-(biphenyl-4-yl)trifluoromethanesulfonic acid (2.58g, 6.0mmol), palladium acetate (61mg, 0.29mmol), and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (261mg, 0.58mmol) were suspended in THF (55mL). After adding 2M potassium carbonate aqueous solution (8.5mL) to this suspension, the mixture was heated to reflux for 24 hours. After cooling, water and methanol were added to the reaction mixture. The resulting solid was filtered and purified by silica gel column chromatography (chloroform / hexane) to obtain the target 2-(biphenyl-4-yl)-4-[2'-(naphthalen-1-yl)-(1,1':4',1''-terphenyl)-4-yl]-6-phenyl-1,3,5-triazine (2.1 g, yield 57%). 1 H-NMR(400MHz,CDCl3)δ(ppm):7.29(dd,J=7.3,1.4Hz,1H),7.33(d,J=8.7Hz,2H),7.35-7.43(m,4H),7.49-7.62(m,8H),7.67-7.76 (m,7H),7.79-7.87(m,5H),8.49(ddd,J=8.5,1.7,1.3Hz,2H),8.72(ddd,J=8.3,1.4,1.2Hz,2H),8.77(ddd,J=8.4,1.9,1.5Hz,2H).

[0134] (Synthesis Example 4: Synthesis of 1-81) [ka]

[0135] Under an argon atmosphere, 2-(biphenyl-4-yl)-4-phenyl-6-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-1,3,5-triazine (3.07 g, 6.0 mmol), [(1,1':2',1'':3'',1'''-quaterphenyl)-4''-yl]trifluoromethanesulfonic acid (3.0 g, 6.6 mmol), palladium acetate (67 mg, 0.30 mmol), and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (286 mg, 0.60 mmol) were suspended in THF (60 mL). 2M potassium carbonate aqueous solution (8.8 mL) was added to the suspension, and the mixture was heated to reflux for 24 hours. After cooling, water and methanol were added to the reaction mixture. The resulting solid was filtered and purified by silica gel column chromatography (chloroform / hexane) to obtain the desired 2-(biphenyl-4-yl)-4-phenyl-6-[3''-phenyl-(1,1':2',1'':4'',1''-quaterphenyl)-4'''-yl]-1,3,5-triazine (3.2 g, 78% yield). 1 H-NMR(400MHz,CDCl3)δ(ppm):6.92(dd,J=6.6,1.2Hz,2H),7.13-7.20(m,3H),7.21(d ,J=1.8Hz,1H),7.25-7.30(m,3H),7.31-7.38(m,5H),7.38-7.54(m,7H),7.55-7.65(m ,4H),7.70(ddd,J=7.3,1.9,1.3Hz,2H),7.79(ddd,J=8.6,2.0,1.7Hz,2H),8.63(ddd, J=8.4,1.8,1.5,2H),8.77(ddd,J=6.8,2.0,1.3,2H),8.82(ddd,J=8.4,1.9,1.6,2H).

[0136] (Comparative Synthesis Example 1) Furthermore, the following ETL-1 described in Patent Document 2 was synthesized according to the method described in Patent Document 2. It can be seen that the azine compound (1) obtained in each synthesis example has a lower crystallization temperature than ETL-1.

[0137] [ka]

[0138] (Comparative Synthesis Example 2: Synthesis of ETL-2) The following ETL-2 was synthesized according to the following synthesis route. The synthesis conditions were the same as those of Synthesis Example-1 or 2. The FD-MS measurement result of the obtained compound ETL-2 was 538.

[0139] [ka]

[0140] The measurement data of the crystallization temperature of the azine compound (1) and ETL-1 prepared in each synthesis example are shown below.

[0141] [Table 1]

[0142] <Fabrication of organic electric field element> Next, the obtained azine compound (1), ETL-1 and ETL-2 were used to carry out device evaluation.

[0143] <Element Example 1 (see Figure 2)> (Preparation of substrate 101 and anode 102) A glass substrate with an indium-tin oxide (ITO) transparent electrode, on which a 2 mm wide ITO film (thickness: 110 nm) was patterned in stripes, was prepared as a substrate with an anode on its surface. The substrate was then washed with isopropyl alcohol and then subjected to surface treatment with ozone ultraviolet cleaning.

[0144] (Preparation for vacuum deposition) After cleaning and surface treatment, each layer was deposited by vacuum deposition on the substrate by vacuum deposition, so that each layer was laminated.

[0145] First, the glass substrate was placed in a vacuum deposition chamber and 1.0×10 -4The pressure was reduced to 10 Pa. Then, each layer was formed in the following order according to the film formation conditions.

[0146] (Fabrication of Hole Injection Layer 103) Sublimation-purified N-[1,1'-biphenyl]-4-yl-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluoren-2-amine and 1,2,3-tris[(4-cyano-2,3,5,6-tetrafluorophenyl)methylene]cyclopropane were deposited at a rate of 0.15 nm / sec to form a 55 nm film to form a hole injection layer.

[0147] (Preparation of the first hole transport layer 1051) A 10 nm film of N-[1,1'-biphenyl]-4-yl-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluoren-2-amine was formed at a rate of 0.15 nm / sec to form a first hole transport layer.

[0148] (Preparation of second hole transport layer 1052) A film of N-phenyl-N-(9,9-diphenylfluoren-2-yl)-N-(1,1'-biphenyl-4-yl)amine was formed to a thickness of 10 nm at a rate of 0.15 nm / sec to form a second hole transport layer.

[0149] (Fabrication of the Light-Emitting Layer 106) A 25 nm thick film was formed by mixing 3-(10-phenyl-9-anthryl)-dibenzofuran and 2,7-bis[N,N-di-(4-tertbutylphenyl)]amino-bisbenzofurano-9,9'-spirofluorene in a ratio of 95:5 (mass ratio) to form an emitting layer. The film formation rate was 0.18 nm / sec.

[0150] (Preparation of First Electron Transport Layer 1071) Sublimation-purified 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)[1,1'-biphenyl]-3-yl]-4,6-diphenyl-1,3,5-triazine was deposited to a thickness of 5 nm at a rate of 0.15 nm / sec to form a first electron transport layer.

[0151] (Preparation of second electron transport layer 1072) A 25 nm film was formed from 2,4-di(4-biphenylyl)-6-[4'-phenyl-(1,1':3',1''-terphenyl)-4-yl]-1,3,5-triazine (compound 1-1) synthesized in Synthesis Example 1 and 8-hydroxyquinolinolato lithium (hereinafter, Liq) in a ratio of 50:50 (mass ratio) to form a second electron transport layer. The film formation rate was 0.15 nm / sec.

[0152] (Preparation of cathode 108) Finally, a metal mask was placed perpendicular to the ITO stripes on the substrate, and the cathode 108 was formed. The cathode had a two-layer structure, with silver / magnesium (mass ratio 1 / 10) and silver being formed in that order to thicknesses of 80 nm and 20 nm, respectively. The silver / magnesium film formation rate was 0.5 nm / sec, and the silver film formation rate was 0.2 nm / sec.

[0153] As a result, the light-emitting area of ​​4 mm2 shown in Figure 2 2 An organic electroluminescence device 100 was produced. The film thickness of each layer was measured using a stylus film thickness measuring instrument (DEKTAK, manufactured by Bruker).

[0154] Furthermore, this element was sealed in a nitrogen atmosphere glove box with oxygen and moisture concentrations of 1 ppm or less by sealing a glass sealing cap and the film-formed substrate (element) with bisphenol F type epoxy resin (manufactured by Nagase ChemteX Corporation).

[0155] A direct current was applied to the organic electroluminescent device fabricated according to the above procedure, and the light-emitting characteristics were evaluated using a luminance meter (product name: BM-9, manufactured by Topcon Technohouse). 2 The current efficiency (cd / A) was measured when current was passed through the device, and the device life (h) during continuous lighting was measured. The device life (h) in Table 3 was measured when the device was fabricated with an initial luminance of 1000 cd / m 2 The luminance decay time was measured when the device was continuously lit when driven at 1000 Hz, and the luminance (cd / m 2 The time required for the temperature to decrease by 5% was measured.

[0156] The voltage, current efficiency, and element life are relative values ​​with the result of element comparative example 1 set as the reference value (100). The obtained measurement results are shown in Table 2.

[0157] <Element Example 2> An organic electroluminescence device was produced and evaluated in the same manner as in Element Example 1, except that the compound (1-25) synthesized in Synthesis Example 2 was used instead of the compound (1-1) in Element Example 1. The measurement results are shown in Table 2. <Comparative element example 1> An organic electroluminescence device was produced and evaluated in the same manner as in Element Example 1, except that ETL-1 was used instead of compound (1-1) in Element Example 1. The measurement results obtained are shown in Table 2. <Comparative element example 2> An organic electroluminescence device was produced and evaluated in the same manner as in Element Example 1, except that ETL-2 was used instead of compound (1-1) in Element Example 1. The measurement results obtained are shown in Table 2.

[0158] [Table 2]

[0159] By using the azine compound according to one embodiment of the present invention, it is possible to provide an organic electroluminescent device excellent in driving voltage, luminous efficiency, and life characteristics.

[0160] The azine compound according to one aspect of the present invention can be used as an electron transport material for an organic electroluminescence element, which contributes to the production of an organic electroluminescence element having a low driving voltage, excellent luminous efficiency, and long life. Furthermore, the azine compound according to one aspect of the present invention can provide an organic electroluminescence element having low power consumption, high luminous efficiency, and long life.

[0161] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

[0162] The entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2020-129833, filed on July 31, 2020, are hereby incorporated by reference as the disclosure of the specification of the present invention. [Explanation of symbols]

[0163] 100. Organic electroluminescent device 1. Substrate 2. Anode 3. Hole injection layer 4. Hole transport layer 5. Emitting layer 6. Electron transport layer 7. Electron injection layer 8. Cathode 101. Circuit Board 102. Anode 103. Hole injection layer 1051. First hole transport layer 1052. Second hole transport layer 106. Emitting layer 1071. First electron transport layer 1072. Second electron transport layer 108. Cathode

Claims

1. An azine compound represented by formula (1): 【Chemistry 1】 During the ceremony, Ar １ represents a phenyl group or a biphenylyl group; Ar ２ represents a biphenylyl group; Ar 3 is a phenyl group, a biphenylyl group, or a naphthyl group; Ar 4 is a phenyl group, a biphenylyl group, or a naphthyl group: n １ is 1 or 2.

2. Ar ３ and Ar ４ The azine compound according to claim 1 , wherein both are phenyl groups.

3. A material for an organic electroluminescent device, comprising the azine compound according to claim 1 or 2.

4. An organic electroluminescent device comprising the material for organic electroluminescent devices according to claim 3 .

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