Triazine compound, material for organic electroluminescent device, electron transport material for organic electroluminescent device, and organic electroluminescent device

Abstract

To provide a triazine compound that contributes to forming an organic electroluminescent device having excellent drive voltage and durability.SOLUTION: A triazine compound has a specific structure represented by formula (1) [where A, B, Ar1, and Ar2 each denote a specific aryl group or the like].SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a triazine compound, a material for an organic electroluminescent device, an electron transport material for an organic electroluminescent device, and an organic electroluminescent device.

Background Art

[0002] Organic electroluminescent devices are used not only for small displays but also for applications such as large TVs and lighting, and their development is being actively carried out. In recent years, the market requirements for organic electroluminescent devices have become increasingly high, and materials excellent in any of current efficiency characteristics, driving voltage characteristics, and long-life characteristics are demanded. Here, Patent Document 1 discloses a triazine compound in which the 2, 4, and 6 positions are substituted with different substituents.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, an organic electroluminescent device using the compound disclosed in Patent Document 1 has insufficient characteristics in driving voltage, current efficiency, and driving life, and further improvement is required.

[0005] One aspect of the present invention is directed to providing a triazine compound, a material for an organic electroluminescent device, and an electron transport material for an organic electroluminescent device that contribute to the production of an organic electroluminescent device having a low driving voltage and excellent durability. Another aspect of the present invention is directed to providing an organic electroluminescent device having a low driving voltage and excellent durability.

Means for Solving the Problems

[0006] According to one aspect of the present invention, a triazine compound represented by formula (1) is provided:

[0007]

Chemical formula

[0008] In formula (1), A represents one group selected from formulas (A-1) to (A-8);

Chemical formula

[0009] B represents one group selected from formulas (B-1) to (B-15);

Chemical formula

[0010] Ar 1 is an aryl group having 6 to 30 carbon atoms, which may be substituted with one or more selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cyano group, a diarylboronyl group, and a phosphine oxide group, or represents a pyridyl group which may be substituted with a methyl group or a phenyl group; Ar 2 is an aryl group having 6 to 30 carbon atoms, which may be substituted with one or more selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cyano group, a diarylboronyl group, and a phosphine oxide group, or represents a pyridyl group which may be substituted with a methyl group or a phenyl group.

[0011] According to another aspect of the present invention, a material for an organic electroluminescent device containing the above triazine compound is provided. According to another aspect of the present invention, there is provided an electron transport material for an organic electroluminescent device containing the above triazine compound. According to another aspect of the present invention, there is provided an organic electroluminescent device containing the above triazine compound.

Advantages of the Invention

[0012] According to one aspect of the present invention, it is possible to provide a triazine compound, a material for an organic electroluminescent device, and an electron transport material for an organic electroluminescent device, which contribute to the production of an organic electroluminescent device having a low driving voltage and excellent durability. According to another aspect of the present invention, it is possible to provide an organic electroluminescent device having a low driving voltage and excellent durability.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0014] Hereinafter, the triazine compound according to one aspect of the present invention will be described in detail.

[0015] <Triazine Compound> The triazine compound according to one aspect of the present invention is represented by the formula (1):

[0016]

Chemical Formula

[0017] In formula (1), A represents one group selected from the formulas (A - 1) to (A - 8);

Chemical Formula

[0018] B represents one group selected from the formulas (B-1) to (B-15); [Chemical formula]

[0019] Ar 1 is an aryl group having 6 to 30 carbon atoms which may be substituted with one or more selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cyano group, a diarylboryl group, and a phosphine oxide group, or represents a pyridyl group which may be substituted with a methyl group or a phenyl group; Ar 2 is an aryl group having 6 to 30 carbon atoms which may be substituted with one or more selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cyano group, a diarylboryl group, and a phosphine oxide group, or represents a pyridyl group which may be substituted with a methyl group or a phenyl group.

[0020] Hereinafter, the triazine compound represented by the formula (1) may also be referred to as triazine compound (1). The definitions of the substituents in the triazine compound (1) and their preferred specific examples are as follows, respectively.

[0021] In the formula, A represents one group selected from the formulas (A-1) to (A-8); B represents one group selected from the formulas (B-1) to (B-15); Ar 1 is an aryl group having 6 to 30 carbon atoms which may be substituted with one or more selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cyano group, a diarylboryl group, and a phosphine oxide group, or represents a pyridyl group which may be substituted with a methyl group or a phenyl group; Ar 2 is an aryl group having 6 to 30 carbon atoms which may be substituted with one or more selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cyano group, a diarylboryl group, and a phosphine oxide group, or represents a pyridyl group which may be substituted with a methyl group or a phenyl group.

[0022]

Chemical formula

[0023]

Chemical formula

[0024] A represents one group selected from formulas (A-1) to (A-8), and is preferably one group selected from formulas (A-1) to (A-4).

[0025] B represents one group selected from formulas (B-1) to (B-15), and is preferably one group selected from formulas (B-1) to (B-4), (B-7) to (B-8), and (B-10) to (B-11), and particularly preferably one group selected from formulas (B-1) to (B-4).

[0026] When the group selected as B does not contain a cyano group, for the combination of A and B, A and B are preferably the same group, such as the combination of the group represented by formula (A-1) and the group represented by formula (B-1).

[0027] Ar 1 and Ar 2Regarding the aryl group having 6 to 18 carbon atoms in the formula, examples thereof preferably include phenyl group, 1-naphthalenyl group, 2-naphthalenyl group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, 2-(1-naphthalenyl)phenyl group, 3-(1-naphthalenyl)phenyl group, 4-(1-naphthalenyl)phenyl group, 2-(2-naphthalenyl)phenyl group, 3-(2-naphthalenyl)phenyl group, 4-(2-naphthalenyl)phenyl group, 4-phenylnaphthalen-1-yl group, 5-phenylnaphthalen-1-yl group, 6-phenylnaphthalen-2-yl group, 7-phenylnaphthalen-2-yl group, 2-phenanthrenyl group, 3-phenanthrenyl group, 9-phenanthrenyl group, 9-anthracenyl group, p-terphenyl group, and 2-triphenylenyl group. These groups may be substituted with one or more selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cyano group, a diarylboril group, and a phosphine oxide group, but an unsubstituted phenyl group, 1-naphthalenyl group, 2-naphthalenyl group, 2-biphenylyl group, 3-biphenylyl group, or 4-biphenylyl group is particularly preferred.

[0028] Ar 1 , and Ar 2Regarding the pyridyl group which may be substituted with a methyl group or a phenyl group, preferred examples include 2-pyridyl group, 3-pyridyl group, 4-pyridyl group, 2-methylpyridin-3-yl group, 2-methylpyridin-4-yl group, 2-methylpyridin-5-yl group, 2-methylpyridin-6-yl group, 3-methylpyridin-2-yl group, 3-methylpyridin-4-yl group, 3-methylpyridin-5-yl group, 3-methylpyridin-6-yl group, 4-methylpyridin-2-yl group, 4-methylpyridin-3-yl group, 2,6-dimethylpyridin-3-yl group, 2,6-dimethylpyridin-4-yl group, 3,6-dimethylpyridin-2-yl group, 3,6-dimethylpyridin-4-yl group, 3,6-dimethylpyridin-5-yl group, 2-phenylpyridin-3-yl group, 2-phenylpyridin-4-yl group, 2-phenylpyridin-5-yl group, 2-phenylpyridin-6-yl group, 3-phenylpyridin-2-yl group, 3-phenylpyridin-4-yl group, 3-phenylpyridin-5-yl group, 3-phenylpyridin-6-yl group, 4-phenylpyridin-2-yl group, 4-phenylpyridin-3-yl group, 2,6-diphenylpyridin-3-yl group, 2,6-diphenylpyridin-4-yl group, 3,6-diphenylpyridin-2-yl group, 3,6-diphenylpyridin-4-yl group, 3,6-diphenylpyridin-5-yl group, 4,6-diphenylpyridin-2-yl group, 2-methyl-6-phenylpyridin-3-yl group, 2-methyl-6-phenylpyridin-4-yl group, 3-methyl-6-phenylpyridin-2-yl group, 3-methyl-6-phenylpyridin-4-yl group, 3-methyl-6-phenylpyridin-5-yl group, 4-methyl-6-phenylpyridin-2-yl group, 6-methyl-2-phenylpyridin-3-yl group, 6-methyl-2-phenylpyridin-4-yl group, 6-methyl-3-phenylpyridin-2-yl group, 6-methyl-3-phenylpyridin-4-yl group, 6-methyl-3-phenylpyridin-5-yl group, and 6-methyl-4-phenylpyridin-2-yl group.

[0029] In the triazine compound according to one embodiment of the present invention represented by formula (1), preferred A, B, Ar 1and Ar 2 The first to seventh aspects, which are combinations of 2 , are as follows.

[0030] ·First aspect A represents one group selected from the formulas (A-1) to (A-8); B represents one group selected from the formulas (B-1) to (B-15); Ar 1 is an aryl group having 6 to 30 carbon atoms, which may be substituted with one or more selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cyano group, a diarylboryl group, and a phosphine oxide group; Ar 2 is an aryl group having 6 to 30 carbon atoms, which may be substituted with one or more selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cyano group, a diarylboryl group, and a phosphine oxide group.

[0031] ·Second aspect A represents one group selected from the formulas (A-1) to (A-4); B represents one group selected from the formulas (B-1) to (B-4), (B-7) to (B-8), and (B-10) to (B-11); Ar 1 is an aryl group having 6 to 30 carbon atoms, which may be substituted with one or more selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cyano group, a diarylboryl group, and a phosphine oxide group, or represents a pyridyl group, which may be substituted with a methyl group or a phenyl group; Ar 2 is an aryl group having 6 to 30 carbon atoms, which may be substituted with one or more selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cyano group, a diarylboryl group, and a phosphine oxide group, or It may be substituted with a methyl group or a phenyl group.

[0032] · The third aspect A represents one group selected from the formulas (A-1) to (A-4); B represents one group selected from the formulas (B-1) to (B-4), (B-7) to (B-8), and (B-10) to (B-11); Ar 1 is an aryl group having 6 to 30 carbon atoms, which may be substituted with one or more selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cyano group, a diarylboronyl group, and a phosphine oxide group; Ar 2 is an aryl group having 6 to 30 carbon atoms, which may be substituted with one or more selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cyano group, a diarylboronyl group, and a phosphine oxide group.

[0033] · The fourth aspect Ar 1 is a phenyl group, 1-naphthalenyl group, 2-naphthalenyl group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, 2-(1-naphthalenyl)phenyl group, 3-(1-naphthalenyl)phenyl group, 4-(1-naphthalenyl)phenyl group, 2-(2-naphthalenyl)phenyl group, 3-(2-naphthalenyl)phenyl group, 4-(2-naphthalenyl)phenyl group, 4-phenylnaphthalen-1-yl group, 5-phenylnaphthalen-1-yl group, 6-phenylnaphthalen-2-yl group, 7-phenylnaphthalen-2-yl group, which may be substituted with one or more selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cyano group, a diarylboronyl group, and a phosphine oxide group; Ar 2 is A phenyl group, 1-naphthalenyl group, 2-naphthalenyl group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, 2-(1-naphthalenyl)phenyl group, 3-(1-naphthalenyl)phenyl group, 4-(1-naphthalenyl)phenyl group, 2-(2-naphthalenyl)phenyl group, 3-(2-naphthalenyl)phenyl group, 4-(2-naphthalenyl)phenyl group, 4-phenylnaphthalen-1-yl group, 5-phenylnaphthalen-1-yl group, 6-phenylnaphthalen-2-yl group, 7-phenylnaphthalen-2-yl group, which may be substituted with one or more selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cyano group, a diarylboril group, and a phosphine oxide group.

[0034] · The fifth aspect Ar 1 is a phenyl group, 1-naphthalenyl group, 2-naphthalenyl group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, which may be substituted with one or more selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cyano group, a diarylboril group, and a phosphine oxide group; Ar 2 is a phenyl group, 1-naphthalenyl group, 2-naphthalenyl group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, which may be substituted with one or more selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cyano group, a diarylboril group, and a phosphine oxide group.

[0035] · The sixth aspect A represents one group selected from formulas (A-1) to (A-4); B represents one group selected from formulas (B-1) to (B-4); Ar 1 is a phenyl group, 1-naphthalenyl group, 2-naphthalenyl group, 2-biphenylyl group, 3-biphenylyl group, or 4-biphenylyl group; Ar2 represents a phenyl group, 1-naphthalenyl group, 2-naphthalenyl group, 2-biphenylyl group, 3-biphenylyl group, or 4-biphenylyl group.

[0036] · Seventh aspect A is a group represented by formula (A-1); B is a group represented by formula (B-1); Ar 1 represents a phenyl group, 1-naphthalenyl group, 2-naphthalenyl group, 2-biphenylyl group, 3-biphenylyl group, or 4-biphenylyl group; Ar 2 represents a phenyl group, 1-naphthalenyl group, 2-naphthalenyl group, 2-biphenylyl group, 3-biphenylyl group, or 4-biphenylyl group.

[0037] [Specific examples of the triazine compound (1)] Among the triazine compounds according to one aspect of the present invention represented by formula (1), specific examples of particularly preferred compounds include the following (1-1) to (1-74), but the triazine compounds according to one aspect of the present invention are not limited thereto.

[0038] [Chemical formula]

[0039] [Chemical formula]

[0040] [Chemical formula]

[0041] [Chemical formula]

[0042] [Chemistry]

[0043] [Chemistry]

[0044] [Chemistry]

[0045] [Chemistry]

[0046] [Chemistry]

[0047] [Chemistry]

[0048] [Chemistry]

[0049] The uses of the triazine compound (1) will be described below. [Material for organic electroluminescent device, electron transport material for organic electroluminescent device] The triazine compound (1) is not particularly limited, and for example, it can be used as a material for an organic electroluminescent device. Further, the triazine compound (1) can be used, for example, as an electron transport material for an organic electroluminescent device. That is, the material for an organic electroluminescent device according to one aspect of the present invention contains the triazine compound (1). Further, the electron transport material for an organic electroluminescent device according to one aspect of the present invention contains the triazine compound (1). The material for an organic electroluminescent device and the electron transport material for an organic electroluminescent device containing the triazine compound (1) contribute to the production of an organic electroluminescent device excellent in driving voltage characteristics and current efficiency.

[0050] <Organic electroluminescent device> The organic electroluminescent device according to one aspect of the present invention contains the triazine compound (1). The configuration of the organic electroluminescent device is not particularly limited, and examples thereof include the configurations of (i) to (vi) shown below. (i): Anode / Light-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 (vi): Anode / Hole injection layer / Charge generation layer / Hole transport layer / Light-emitting layer / Electron transport layer / Cathode

[0051] Hereinafter, the organic electroluminescent device according to one aspect of the present invention will be described in more detail with reference to FIG. 1, taking the configuration of (vi) above as an example. FIG. 1 is a schematic cross-sectional view showing an example of the laminated structure of an organic electroluminescent device containing a triazine compound according to one aspect of the present invention. Note that the organic electroluminescence device shown in FIG. 1 has a so-called bottom emission type device configuration, but the organic electroluminescence device according to one aspect of the present invention is not limited to the bottom emission type device configuration. That is, the organic electroluminescence device according to one aspect of the present invention may have a top emission type device configuration or other known device configurations.

[0052] The organic electroluminescent device 100 includes a substrate 1, an anode 2, a hole injection layer 3, a charge generation layer 4, a hole transport layer 5, a light-emitting layer 6, an electron transport layer 7, and a cathode 8 in this order. However, some of these layers may be omitted, or conversely, other layers may be added. For example, an electron injection layer may be provided between the electron transport layer 7 and the cathode 8, the charge generation layer 4 may be omitted, and the hole transport layer 5 may be directly provided on the hole injection layer 3. Also, for example, a single layer having the functions of a plurality of layers, such as an electron injection / transport layer having the functions of an electron injection layer and an electron transport layer in a single layer, may be provided instead of the plurality of layers. Furthermore, for example, a single-layer hole transport layer 5 and a single-layer electron transport layer 7 may each be composed of a plurality of layers.

[0053] [Layer containing the triazine compound represented by formula (1)] The organic electroluminescent device includes at least one layer selected from the group consisting of a light-emitting layer and a layer between the light-emitting layer and the cathode and contains the triazine compound represented by the above formula (1). Therefore, in the configuration example shown in FIG. 1, the organic electroluminescent device 100 contains the triazine compound (1) in at least one layer selected from the group consisting of the light-emitting layer 6 and the electron transport layer 7. In particular, it is preferable that the electron transport layer 7 contains the triazine compound (1). Note that the triazine compound (1) may be contained in a plurality of layers included in the organic electroluminescent device, and when an electron injection layer is provided between the electron transport layer and the cathode, the electron injection layer may contain the triazine compound (1). Hereinafter, the organic electroluminescent device 100 in which the electron transport layer 7 contains the triazine compound (1) will be described.

[0054] [Substrate 1] The substrate is not particularly limited, and examples thereof include a glass plate, a quartz plate, and a plastic plate. Also, in the case of a configuration in which light emission is extracted from the substrate 1 side, the substrate 1 is transparent to the wavelength of light.

[0055] Examples of the plastic film having light transmissivity 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.

[0056] [Anode 2] An anode 2 is provided on the substrate 1 (on the side of the hole injection layer 3). In the case of an organic electroluminescent element configured such that light emission passes through the anode and is extracted, the anode is formed of a material that allows or substantially allows the light emission to pass through.

[0057] The transparent material used for the anode is not particularly limited. Examples 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. In the case of an organic electroluminescent element configured to extract light only from the cathode side, the transmission characteristics of the anode are not important. Therefore, examples of the material used for the anode in this case include gold, iridium, molybdenum, palladium, platinum, and the like. A buffer layer (electrode interface layer) may be provided on the anode.

[0058] [Hole injection layer 3, hole transport layer 5] Between the anode 2 and the light-emitting layer 6 described later, a hole injection layer 3, a charge generation layer 4 described later, and a hole transport layer 5 are provided in this order from the anode 2 side. The hole injection layer and the hole transport layer have the function of transmitting holes injected from the anode to the light-emitting layer. By interposing the hole injection layer and the hole transport layer between the anode and the light-emitting layer, a large number of holes can be injected into the light-emitting layer at a lower electric field.

[0059] In addition, the hole injection layer and the hole transport layer also function as an electron barrier layer. That is, electrons injected from the cathode and transported from the electron injection layer and / or the electron transport layer to the light-emitting layer are suppressed from leaking into the hole injection layer and / or the hole transport layer by the electron barrier existing at the interface between the light-emitting layer and the hole injection layer and / or the hole transport layer. As a result, the electrons are accumulated at the interface in the light-emitting layer, bringing about effects such as improved current efficiency, and an organic electroluminescent device with excellent light-emitting performance can be obtained.

[0060] The materials for the hole injection layer and the hole transport layer are those having at least any one of hole injection property, hole transport property, and electron barrier property. The materials for the hole injection layer and the hole transport layer may be either organic or inorganic.

[0061] Specific examples of the materials for the hole injection layer and the hole transport layer 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 (especially thiophene oligomers), porphyrin compounds, aromatic tertiary amine compounds, styrylamine compounds, and the like. Among these, porphyrin compounds, aromatic tertiary amine compounds, and styrylamine compounds are preferred, and aromatic tertiary amine compounds are particularly preferred.

[0062] Specific examples of the aromatic tertiary amine compound and the styrylamine compound 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)quarterphenyl, 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), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (MTDATA), and the like. Inorganic compounds such as p-type Si and p-type SiC can also be cited as an example of the material for the hole injection layer and the material for the hole transport layer.

[0063] The hole injection layer and the hole transport layer may have a single-layer structure composed of one or more materials, or may have a laminated structure composed of a plurality of layers of the same composition or different compositions.

[0064] [Charge generation layer 4] A charge generation layer 4 may be provided between the hole injection layer 3 and the hole transport layer 5. The material of the charge generation layer is not particularly limited, and examples thereof include dipyridino[2,3-f:2’,3’-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HAT-CN). The charge generation layer may have a single-layer structure composed of one or more materials, or may have a laminated structure composed of a plurality of layers of the same composition or different compositions.

[0065] [Light-emitting layer 6] A light-emitting layer 6 is provided between the hole transport layer 5 and the electron transport layer 7 described later. Examples of the material of the light-emitting layer include phosphorescent materials, fluorescent materials, and thermally activated delayed fluorescent materials. In the light-emitting layer, electron-hole pairs recombine, and as a result, light emission occurs.

[0066] The light-emitting layer may be composed of a single low-molecular material or a single polymer material, but more generally, it is composed of a host material doped with a guest compound. Light emission mainly occurs from the dopant and can have any color.

[0067] Examples of the host material include compounds having a biphenyl group, a fluorenyl group, a triphenylsilyl group, a carbazole group, a pyrenyl group, and an anthryl group. More specifically, DPVBi (4,4'-bis(2,2-diphenylvinyl)-1,1'-biphenyl), BCzVBi (4,4'-bis(9-ethyl-3-carbazovinylene)1,1'-biphenyl), TBADN (2-tert-butyl-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, etc. are included.

[0068] Examples of the fluorescent dopant include anthracene, pyrene, tetracene, xanthene, perylene, rubrene, coumarin, rhodamine, quinacridone, dicyanomethylene pyran compounds, thiopyran compounds, polymethine compounds, pyrylium, thiapyrylium compounds, fluorene derivatives, periflanthene derivatives, indenoperylene derivatives, bis(azinyl)amine boron compounds, bis(azinyl)methane compounds, carbostyryl compounds, and the like. The fluorescent dopant may be a combination of two or more selected from these.

[0069] Examples of the phosphorescent dopant include organometallic complexes of transition metals such as iridium, platinum, palladium, and osmium.

[0070] Specific examples of the fluorescent dopant and the phosphorescent dopant include Alq3 (tris(8-hydroxyquinoline)aluminum), DPAVBi (4,4'-bis[4-(di-p-tolylamino)styryl]biphenyl), perylene, bis[2-(4-n-hexylphenyl)quinoline](acetylacetonato)iridium(III), Ir(PPy)3 (tris(2-phenylpyridine)iridium(III)), and FIrPic (bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl)iridium(III))), and the like.

[0071] Further, the light-emitting material is not limited to being contained only in the light-emitting layer. For example, the light-emitting material may be contained in a layer adjacent to the light-emitting layer (the hole transport layer 5 or the electron transport layer 7). Thereby, the current efficiency of the organic electroluminescent element can be further increased.

[0072] The light-emitting layer may have a single-layer structure composed of one or more materials, or may have a laminated structure composed of a plurality of layers of the same composition or different compositions.

[0073] [Electron transport layer 7] An electron transport layer 7 is provided between the light-emitting layer 6 and the cathode 8 described later. The electron transport layer has a function of transmitting electrons injected from the cathode to the light-emitting layer. By interposing the electron transport layer between the cathode and the light-emitting layer, electrons are injected into the light-emitting layer at a lower electric field.

[0074] As described above, the electron transport layer preferably contains the triazine compound represented by the above formula (1).

[0075] In addition to the triazine compound (1), the electron transport layer may further contain a conventionally known electron transport material. Examples of the conventionally known electron transport materials include lithium 8-hydroxyquinolinate (Liq), zinc bis(8-hydroxyquinolinate), copper bis(8-hydroxyquinolinate), manganese bis(8-hydroxyquinolinate), aluminum tris(8-hydroxyquinolinate), aluminum tris(2-methyl-8-hydroxyquinolinate), gallium tris(8-hydroxyquinolinate), beryllium bis(10-hydroxybenzo[h]quinolinate), zinc bis(10-hydroxybenzo[h]quinolinate), gallium bis(2-methyl-8-quinolinato)chloride, gallium bis(2-methyl-8-quinolinato)(o-cresolato), aluminum bis(2-methyl-8-quinolinato)-1-naphtholate, or gallium bis(2-methyl-8-quinolinato)-2-naphtholate, 2-[3-(9-phenanthrenyl)-5-(3-pyridinyl)phenyl]-4,6-diphenyl-1,3,5-triazine, and 2-(4,’’-di-2-pyridinyl[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-quinolinolato)-4-(phenylphenolato)aluminum), and beryllium bis(10-hydroxybenzo[h]quinolinate), etc.

[0076] The electron transport layer may have a single-layer structure composed of one or more than two materials, or may have a laminated structure composed of a plurality of layers with the same composition or different compositions. When the electron transport layer has a two-layer structure with the first electron transport layer on the light-emitting layer side and the second electron transport layer on the cathode side, it is preferable that the second electron transport layer contains the triazine compound (1).

[0077] [Cathode 8] A cathode 8 is provided on the electron transport layer 7. In the case of an organic electroluminescence device configured to extract only the light emitted through the anode, the cathode can be formed from any conductive material. Examples of the cathode material include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al 2 O 3 ) mixture, indium, lithium / aluminum mixture, rare earth metals, and the like. A buffer layer (electrode interface layer) may be provided on the cathode (on the electron transport layer side).

[0078] [Formation method of each layer] Except for the electrodes (anode, cathode) described above, each layer can be formed by thinning the material of each layer (together with a material such as a binder resin and a solvent, if necessary) by a known method such as vacuum evaporation, spin coating, casting, LB (Langmuir-Blodgett method), etc. There is no particular limitation on the film thickness of each layer formed in this way, and it can be appropriately selected according to the situation, but it is usually in the range of 5 nm to 5 μm.

[0079] The anode and the cathode can be formed by thinning the electrode material into a thin film by methods such as vapor deposition or sputtering. A pattern may be formed through a mask of a desired shape during vapor deposition or sputtering, or after forming a thin film by vapor deposition, sputtering, etc., a pattern of a desired shape may be formed by photolithography.

[0080] The film thickness of the anode and the cathode is preferably 1 μm or less, and more preferably 10 nm or more and 200 nm or less.

[0081] The organic electroluminescent element according to one aspect of the present invention may be used as a kind of lamp such as for illumination or an exposure light source, or as a projection device of a type that projects an image, or a display device (display) of a type that directly visualizes still images or moving images. When used as a display device for video playback, the driving method may be either a simple matrix (passive matrix) method or an active matrix method. Further, by using two or more kinds of the organic electroluminescent elements of this aspect having different emission colors, a full-color display device can be manufactured.

[0082] Note that the triazine compound (1) according to one aspect of the present invention can be synthesized by appropriately combining known reactions (for example, Suzuki-Miyaura cross-coupling reaction, etc.).

Examples

[0083] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not to be construed as being limited by these examples in any way.

[0084] 1 1H-NMR measurement was performed using Gemini200 (manufactured by Varian). The glass transition temperature measurement was performed using DSC7020 (manufactured by Hitachi High-Technologies Corporation). The light emission characteristics of the organic electroluminescent element were evaluated by applying a direct current to the fabricated element at room temperature and using a luminance meter (product name: BM-9, manufactured by Topcon Techno House).

[0085] Synthesis Example - 1 Synthesis of Compound (1-2) [Chemical formula] [Chemical formula] [Chemical formula] [Chemical formula]

[0086] Under a nitrogen stream, to a flask containing 2,4-dibromophenol (10.0 g, 39.7 mmol), 2-naphthaleneboronic acid (15.0 g, 87.3 mmol), and PdCl 2 (amphos) 2 (281 mg, 0.40 mmol), tetrahydrofuran (132 ml) was added. Further, 2 M aqueous potassium phosphate solution (59.5 ml, 119.1 mmol) was added, and the mixture was stirred at 70 °C for 2 hours. After allowing to cool to room temperature, water and toluene were added to the reaction solution and separated by liquid separation. The organic layer was dehydrated with magnesium sulfate, and then the solvent was distilled off under reduced pressure. The obtained solid was dissolved in toluene (200 ml) at 60 °C, silica gel (8.5 g) was added, and the mixture was stirred for 30 minutes. After hot filtration of this suspension, the solvent was distilled off under reduced pressure to obtain a white solid (yield 7.8 g) of 2,4-di(naphthalen-2-yl)phenol.

[0087] Under a nitrogen stream, to a flask containing 2,4-di(naphthalen-2-yl)phenol (4.5 g, 13.0 mmol), pyridine (2.1 ml, 26.0 mmol), and toluene (130 ml), trifluoromethanesulfonic anhydride (Tf 2(3.2 mL, 19.5 mmol) was added dropwise. After stirring at room temperature for 3 hours, water and toluene were added to the reaction solution and separated by liquid separation. The organic layer was dehydrated with magnesium sulfate, and then the solvent was distilled off under reduced pressure. Heptane (50 mL) was added to the obtained oily crude product, and a solid was precipitated by stirring at room temperature. The precipitated solid was collected by suction filtration to obtain a white solid (yield 5.5 g) of 2,4-di(naphthalen-2-yl)phenyl trifluoromethanesulfonate.

[0088] Under a nitrogen stream, 2,4-di(naphthalen-2-yl)phenyl trifluoromethanesulfonate (4.5 g, 9.4 mmol), bis(pinacolato)diboron (3.6 g, 14.1 mmol), PdCl 2 [(Pcy 3 )] 2 (139 mg, 0.19 mmol), and potassium acetate (2.8 g, 28.2 mmol) were placed in a flask, 1,4-dioxane (47 mL) was added, and the mixture was stirred at 100 °C for 22 hours. After allowing to cool to room temperature, the solid was filtered off from the reaction solution by suction filtration, and then the solvent was distilled off under reduced pressure. Methanol (100 mL) was added to the obtained oily crude product, and a solid was precipitated by stirring at room temperature. The precipitated solid was collected by suction filtration to obtain a solid (yield 3.5 g) of 2-[2,4-di(naphthalen-2-yl)phenyl]-4,4,5,5-tetramethyl-1,3,2-dioxaborolane.

[0089] Under a nitrogen stream, 2-chloro-4,6-di(biphenyl-4-yl)-1,3,5-triazine (2.5 g, 6.0 mmol), 2-[2,4-di(naphthalen-2-yl)phenyl]-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (3.0 g, 6.6 mmol), and Pd(PPh 3 ) 4Tetrahydrofuran (198 ml) was added to a flask containing (138 mg, 0.12 mmol). Further, 2 M aqueous potassium phosphate solution (9 ml, 17.9 mmol) was added, and the mixture was stirred at 70 °C for 22 hours. After allowing to cool to room temperature, water and toluene were added to the reaction solution and separated by liquid separation. The organic layer was dehydrated with magnesium sulfate, and then the solvent was distilled off under reduced pressure. Ethanol (300 ml) was added to the obtained oily crude product, and a solid was precipitated by stirring at room temperature. The precipitated solid was collected by suction filtration. The obtained solid was washed with water and ethanol, then dissolved in toluene (200 mL), activated carbon (0.4 g) was added, and the mixture was heated and stirred at 100 °C for 1 hour. The activated carbon was filtered off by suction filtration through a Celite-lined Kiriyama funnel, and the filtrate was distilled off under reduced pressure. Further recrystallization from a toluene (130 ml) solution gave a white solid (yield 1.8 g) of compound (1-2). The glass transition temperature was 116 °C.

[0090] 1 H-NMR(CDCl 3 )δ(ppm):8.71(d,1H),8.24(m,5H),8.11(m,1H),7.93-8.04(m,5H),7.91(m,2H),7.85(m,1H),7.78(m,1H),7.61(m,4H),7,36-7.58(m,15H).

[0091] Subsequently, device evaluation was carried out using the obtained compound.

[0092] Device Example-1 (see Figure 2) (Preparation of Substrate 101 and Anode 102) As a substrate having an anode on its surface, a glass substrate with an indium tin oxide (ITO) transparent electrode (2 mm wide, ITO film thickness 110 nm) patterned in stripes was prepared. Subsequently, this substrate was washed with isopropyl alcohol and then surface-treated by ozone ultraviolet cleaning.

[0093] (Preparation for Vacuum Deposition) On the substrate subjected to surface treatment after washing, each layer was vacuum-deposited by the vacuum deposition method, and each layer was laminated and formed. First, the glass substrate was introduced into the vacuum evaporation chamber and the pressure was reduced to 1.0×10 -4 Pa. Then, they were respectively fabricated according to the film formation conditions of each layer in the following order.

[0094] (Fabrication of the 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-fluorene-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 / second to form a 10-nm film, thereby fabricating the hole injection layer 103.

[0095] (Fabrication of the first hole transport layer 1051) Sublimation-purified N-[1,1'-biphenyl]-4-yl-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluorene-2-amine was deposited at a rate of 0.15 nm / second to form an 85-nm film, thereby fabricating the first hole transport layer 1051.

[0096] (Fabrication of the second hole transport layer 1052) Sublimation-purified N-phenyl-N-(9,9-diphenylfluorene-2-yl)-N-(1,1'-biphenyl-4-yl)amine was deposited at a rate of 0.15 nm / second to form a 5-nm film, thereby fabricating the second hole transport layer 1052.

[0097] (Fabrication of the light-emitting layer 106) Sublimation-purified 3-(10-phenyl-9-anthryl)-dibenzofuran and 2,7-bis[N,N-di-(4-tert-butylphenyl)]amino-bisbenzofuran-9,9'-spirofluorene were deposited at a ratio of 95:5 (mass ratio) to form a 20-nm film, thereby fabricating the light-emitting layer 106. The film formation rate was 0.18 nm / second.

[0098] (Fabrication of the 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 at a rate of 0.05 nm / second to form a 6-nm film, thereby fabricating the first electron transport layer 1071.

[0099] (Fabrication of the second electron transport layer 1072) The compound (1-2) synthesized in Synthesis Example-1 and Liq were deposited at a ratio of 50:50 (mass ratio) to form a 25-nm film, thereby fabricating the second electron transport layer 1072. The deposition rate was 0.15 nm / second.

[0100] (Fabrication of the cathode 108) Finally, a metal mask was arranged so as to be perpendicular to the ITO stripe on the substrate, and the cathode 108 was deposited. The cathode was formed by depositing silver / magnesium (mass ratio 1 / 10) and silver in this order, with thicknesses of 80 nm and 20 nm respectively, to form a two-layer structure. The deposition rate of silver / magnesium was 0.5 nm / second, and the deposition rate of silver was 0.2 nm / second.

[0101] As described above, an organic electroluminescent device 100 having a light-emitting area of 4 mm as shown in FIG. 2 2 was fabricated. The thickness of each film was measured using a stylus profilometer (DEKTAK, manufactured by Bruker).

[0102] Furthermore, this device was sealed in a nitrogen atmosphere glove box with an oxygen and moisture concentration of 1 ppm or less. The sealing was performed using a glass sealing cap and a film-forming substrate (device) with a bisphenol F type epoxy resin (manufactured by Nagase ChemteX).

[0103] A direct current was applied to the organic electroluminescent device fabricated as described above, and the light-emitting characteristics were evaluated using a luminance meter (product name: BM-9, manufactured by Topcon Techno House). As the light-emitting characteristics, the current efficiency (cd / A) and the driving voltage (V) when a current density of 10 mA / cm 2 was passed were measured. The current efficiency and the driving voltage are relative values with the results in Device Reference Example 1 described later as the reference value (100). The obtained measurement results are shown in Table 1.

[0104] Element reference example - 1 In element Example - 1, an organic electroluminescent element was fabricated and evaluated in the same manner as in element Example - 1, except that the compound (ETL - 1) described in Japanese Patent Application Laid - Open No. 2019 - 534548 was used instead of the compound (1 - 2). The obtained measurement results are shown in Table 1.

[0105]

Chemical formula

[0106]

Table 1

[0107] The triazine compound (1) according to one aspect of the present invention has a wide band gap and a high triplet excitation level, and thus can be suitably used not only for conventional fluorescent element applications but also for organic electroluminescent elements using phosphorescence or thermally activated delayed fluorescence (TADF).

Explanation of symbols

[0108] 1,101 Substrate 2,102 Anode 3,103 Hole injection layer 4,104 Charge generation layer 5,105 Hole transport layer 6,106 Light - emitting layer 7,107 Electron transport layer 8,108 Cathode 51,1051 First hole transport layer 52,1052 Second hole transport layer 71,1071 First electron transport layer 72,1072 Second electron transport layer 100 Organic electroluminescent element

Claims

1. A triazine compound represented by formula (1): 【Chemical 1】 In the formula, A represents one group selected from formulas (A-1) to (A-6); [Chemical Formula 2] B represents one group selected from formulas (B-1) to (B-6); 【Chemical Formula 3】 A and B represent the same group; Ar １ is One or more selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cyano group, a diarylboryl group, and a phosphine oxide group, and Represents an aryl group having 6 to 30 carbon atoms which may be substituted; Ar ２ is Represents an aryl group having 6 to 30 carbon atoms which may be substituted with one or more selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cyano group, a diarylboryl group, and a phosphine oxide group.

2. A represents one group selected from formulas (A-1) to (A-4); B represents one group selected from formulas (B-1) to (B-4); The triazine compound according to claim 1, wherein A and B represent the same group.

3. Ar １ is A phenyl group, 1-naphthalenyl group, 2-naphthalenyl group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, 2-(1-naphthalenyl)phenyl group, 3-(1-naphthalenyl)phenyl group, 4-(1-naphthalenyl)phenyl group, 2-(2-naphthalenyl)phenyl group, 3-(2-naphthalenyl)phenyl group, 4-(2-naphthalenyl)phenyl group, 4-phenylnaphthalen-1-yl group, 5-phenylnaphthalen-1-yl group, 6-phenylnaphthalen-2-yl group, 7-phenylnaphthalen-2-yl group, which may be substituted with one or more selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cyano group, a diarylboryl group, and a phosphine oxide group; Ar ２ is The triazine compound according to claim 1 or 2, wherein the phenyl group, 1-naphthalenyl group, 2-naphthalenyl group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, 2-(1-naphthalenyl)phenyl group, 3-(1-naphthalenyl)phenyl group, 4-(1-naphthalenyl)phenyl group, 2-(2-naphthalenyl)phenyl group, 3-(2-naphthalenyl)phenyl group, 4-(2-naphthalenyl)phenyl group, 4-phenylnaphthalen-1-yl group, 5-phenylnaphthalen-1-yl group, 6-phenylnaphthalen-2-yl group, 7-phenylnaphthalen-2-yl group may be substituted with one or more selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cyano group, a diarylboronyl group, and a phosphine oxide group.

4. Ar １ is Represents a phenyl group, 1-naphthalenyl group, 2-naphthalenyl group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, which may be substituted with one or more selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cyano group, a diarylboronyl group, and a phosphine oxide group; Ar ２ is The triazine compound according to any one of claims 1 to 3, wherein the phenyl group, 1-naphthalenyl group, 2-naphthalenyl group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group may be substituted with one or more selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a cyano group, a diarylboronyl group, and a phosphine oxide group.

5. A represents one group selected from formulas (A-1) to (A-4); B represents one group selected from formulas (B-1) to (B-4); A and B represent the same group; Ar １ is Represents a phenyl group, 1-naphthalenyl group, 2-naphthalenyl group, 2-biphenylyl group, 3-biphenylyl group, or 4-biphenylyl group; Ar ２ is The triazine compound according to any one of claims 1 to 4, wherein the phenyl group, 1-naphthalenyl group, 2-naphthalenyl group, 2-biphenylyl group, 3-biphenylyl group, or 4-biphenylyl group.

6. A is a group represented by formula (A-1); B is a group represented by formula (B-1); Ar １ is represents a phenyl group, 1-naphthalenyl group, 2-naphthalenyl group, 2-biphenylyl group, 3-biphenylyl group, or 4-biphenylyl group; Ar ２ is The triazine compound according to any one of claims 1 to 5, which represents a phenyl group, 1-naphthalenyl group, 2-naphthalenyl group, 2-biphenylyl group, 3-biphenylyl group, or 4-biphenylyl group.

7. A is a group represented by formula (A-1); B is a group represented by formula (B-1); Ar 1 is represents a phenyl group, 1-naphthalenyl group, 2-naphthalenyl group; Ar 2 is The triazine compound according to claim 1, which represents a phenyl group, 1-naphthalenyl group, 2-naphthalenyl group.

8. A material for an organic electroluminescent device containing the triazine compound according to any one of claims 1 to 7.

9. An electron transport material for an organic electroluminescent device containing the triazine compound according to any one of claims 1 to 7.

10. An organic electroluminescent device containing the triazine compound according to any one of claims 1 to 7.

Images