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

Abstract

To provide an azine compound having high solubility and contributing to making an organic electroluminescent device that can exhibit excellent drive voltage, luminous efficiency and service life, and a material for organic electroluminescent devices and an organic electroluminescent device each including the azine compound.SOLUTION: An azine compound has a specific structure represented by the formula (1).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an azine 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 vigorously carried out. In recent years, the market requirements for organic electroluminescent devices have become increasingly high, and materials that are excellent in any of current efficiency characteristics, driving voltage characteristics, and long-life characteristics are demanded. Here, Patent Document 1 discloses an azine 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, luminous efficiency, and driving life, and further improvement is required.

[0005] One aspect of the present invention aims to provide an azine compound, a material for an organic electroluminescent device, and an electron transport material for an organic electroluminescent device that have high solubility and contribute to the production of an organic electroluminescent device having a low driving voltage and excellent luminous efficiency characteristics and life characteristics. Another aspect of the present invention aims to provide an organic electroluminescent device having a low driving voltage and excellent luminous efficiency characteristics and life characteristics.

Means for Solving the Problems

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

[0007] [ka] In formula (1), A represents any one group selected from formulas (A-1) to (A-18):

[0008] [ka]

[0009] B represents a phenyl group; Ar 1 teeth, represents a phenyl group or a biphenylyl group which may be substituted with one or more groups 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 teeth, an aryl group having 6 to 30 carbon atoms which may be substituted with one or more groups 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 represents a pyridyl group which may be substituted with one or more groups selected from the group consisting of a methyl group and a phenyl group.

[0010] According to another aspect of the present invention, there is provided a material for an organic electroluminescent device, which comprises the above-mentioned azine compound. According to another aspect of the present invention, there is provided an electron transport material for an organic electroluminescent device, which comprises the above-mentioned azine compound. According to another aspect of the present invention, there is provided an organic electroluminescent device comprising the above azine compound. [Effects of the Invention]

[0011] According to one aspect of the present invention, it is possible to provide an azine compound, a material for an organic electroluminescent element, and an electron-transporting material for an organic electroluminescent element, which contribute to the production of an organic electroluminescent element having a low driving voltage and excellent luminous efficiency and life characteristics, and which has high solubility and can be easily subjected to extraction and purification procedures after synthesis. According to another aspect of the present invention, it is possible to provide an organic electroluminescent device that has a low driving voltage and excellent luminous efficiency and life characteristics. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic cross-sectional view showing an example of a layer structure of an organic electroluminescent element containing an azine compound according to one embodiment of the present invention. [Figure 2] FIG. 1 is a schematic cross-sectional view showing an example of a layer structure of an organic electroluminescent element containing an azine compound according to one embodiment of the present invention (Element Example 1). DETAILED DESCRIPTION OF THE INVENTION

[0013] The azine compound according to one embodiment of the present invention will be described in detail below.

[0014] <Azine compounds> The azine compound according to one embodiment of the present invention is represented by formula (1):

[0015] [ka] In formula (1), A represents any one group selected from formulas (A-1) to (A-18):

[0016] [ka]

[0017] B represents a phenyl group; Ar 1 teeth, represents a phenyl group or a biphenylyl group which may be substituted with one or more groups 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 teeth, an aryl group having 6 to 30 carbon atoms which may be substituted with one or more groups 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 represents a pyridyl group which may be substituted with one or more groups selected from the group consisting of a methyl group and a phenyl group.

[0018] [About A and B] In formula (1), A represents any one group selected from formulas (A-1) to (A-18):

[0019] [ka]

[0020] B represents a phenyl group.

[0021] A represents any one group selected from the formulae (A-1) to (A-18), and preferably represents any one group selected from the formulae (A-1) to (A-8).

[0022] [Ar 1 ,Ar 2 About Ar 1 teeth, represents a phenyl group or a biphenylyl group which may be substituted with one or more groups 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 1 is more preferably an unsubstituted phenyl group, a 2-biphenylyl group, a 3-biphenylyl group, or a 4-biphenylyl group. Ar 2 teeth, an aryl group having 6 to 30 carbon atoms which may be substituted with one or more groups 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 represents a pyridyl group which may be substituted with one or more groups selected from the group consisting of a methyl group and a phenyl group.

[0023] Ar 2 which may be substituted with one or more groups 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, a phenyl group, a 1-naphthalenyl group, a 2-naphthalenyl group, a 2-biphenylyl group, a 3-biphenylyl group, a 4-biphenylyl group, a 2-(1-naphthalenyl)phenyl group, a 3-(1-naphthalenyl)phenyl group, a 4-(1-naphthalenyl)phenyl group, a 2-( Preferably, Ar is a 2-naphthalenyl)phenyl group, a 3-(2-naphthalenyl)phenyl group, a 4-(2-naphthalenyl)phenyl group, a 4-phenylnaphthalen-1-yl group, a 5-phenylnaphthalen-1-yl group, a 6-phenylnaphthalen-2-yl group, a 7-phenylnaphthalen-2-yl group, a 2-phenanthrenyl group, a 3-phenanthrenyl group, a 9-phenanthrenyl group, a 9-anthracenyl group, a p-terphenyl group, or a 2-triphenylenyl group. 2 is more preferably an unsubstituted phenyl group, 1-naphthalenyl group, 2-naphthalenyl group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, or 9-phenanthrenyl group, and particularly preferably an unsubstituted phenyl group, 2-naphthalenyl group, 2-biphenylyl group, 4-biphenylyl group, or 9-phenanthrenyl group.

[0024] [A,Ar 2 A preferred combination of A represents any one group selected from formulas (A-1) to (A-8), Ar 2preferably represents an aryl group having 6 to 30 carbon atoms which may be substituted with one or more groups 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. A represents any one group selected from formulas (A-2) to (A-6), Ar 2 is more preferably an unsubstituted phenyl group, a 1-naphthalenyl group, a 2-naphthalenyl group, a 2-biphenylyl group, a 3-biphenylyl group, a 4-biphenylyl group, or a 9-phenanthrenyl group; A represents any one group selected from formulas (A-2) to (A-6), Ar 2 is particularly preferably an unsubstituted phenyl group, a 2-naphthalenyl group, a 2-biphenylyl group, a 4-biphenylyl group, or a 9-phenanthrenyl group.

[0025] [Specific examples of azine compound (1)] Among the azine compounds represented by formula (1) according to one embodiment of the present invention, particularly preferred specific examples include those represented by the following formulae (1-1) to (1-96), but the azine compounds according to one embodiment of the present invention are not limited thereto.

[0026] [ka]

[0027] [ka]

[0028] [ka]

[0029] [ka]

[0030] [ka]

[0031] Among the compounds represented by formulae (1-1) to (1-96), the compounds represented by formulae (1-3), (1-15), (1-27), (1-39) and (1-94) are particularly preferred.

[0032] The uses of the azine compound (1) will be explained below. <Materials for organic electroluminescent devices, electron transport materials for organic electroluminescent devices> Although not particularly limited, the azine compound (1) can be used, for example, as a material for an organic electroluminescent device, and the azine compound (1) can be used, for example, as an electron transport material for an organic electroluminescent device. That is, a material for organic electroluminescent elements according to one embodiment of the present invention contains azine compound (1). Also, an electron-transporting material for organic electroluminescent elements according to one embodiment of the present invention contains azine compound (1). The material for organic electroluminescent elements and the electron-transporting material for organic electroluminescent elements containing azine compound (1) contribute to the production of organic electroluminescent elements excellent in driving voltage, luminous efficiency, and life characteristics.

[0033] <Organic electroluminescent device> The organic electroluminescent device according to one aspect of the present invention contains an azine compound (1). The configuration of the organic electroluminescent device is not particularly limited, but examples thereof include the following configurations (i) to (vi). (i): Anode / Emitting layer / Cathode (ii): Anode / hole transport layer / light-emitting layer / cathode (iii): Anode / 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

[0034] Hereinafter, an organic electroluminescent device according to an embodiment of the present invention will be described in more detail, taking the above-mentioned configuration (vi) as an example, with reference to Fig. 1. Fig. 1 is a schematic cross-sectional view showing an example of a layered configuration of an organic electroluminescent device containing an azine compound according to an embodiment of the present invention. 1 has a so-called bottom-emission type element configuration, the organic electroluminescence element according to one embodiment of the present invention is not limited to the bottom-emission type element configuration. That is, the organic electroluminescence element according to one embodiment of the present invention may have a top-emission type element configuration or any other known element configuration.

[0035] The organic electroluminescent device 100 comprises, in this order, a substrate 1, an anode 2, a hole injection layer 3, a charge generation layer 4, a hole transport layer 5, an emitting layer 6, an electron transport layer 7, and a cathode 8. However, some of these layers may be omitted, or other layers may be added. For example, an electron injection layer may be provided between the electron transport layer 7 and the cathode 8, or the charge generation layer 4 may be omitted and the hole transport layer 5 may be provided directly on the hole injection layer 3. Alternatively, a single layer having the functions of multiple layers, such as an electron injection / transport layer that combines the functions of both an electron injection layer and an electron transport layer, may be provided instead of the multiple layers. Furthermore, for example, the single-layer hole transport layer 5 and the single-layer electron transport layer 7 may each be composed of multiple layers.

[0036] [Layer containing an azine compound represented by formula (1)] An organic electroluminescent device contains the azine compound represented by the formula (1) in one or more layers selected from the group consisting of an emitting layer and a layer between the emitting layer and a cathode. Therefore, in the exemplary configuration shown in FIG. 1 , the organic electroluminescent device 100 contains the azine compound (1) in at least one layer selected from the group consisting of the emitting layer 6 and the electron transport layer 7. It is particularly preferable that the electron transport layer 7 contains the azine compound (1). The azine compound (1) may be contained in multiple layers of 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 azine compound (1). In the following, an organic electroluminescent device 100 in which the electron transport layer 7 contains the azine compound (1) will be described.

[0037] [Board 1] There are no particular limitations on the substrate, and examples include a glass plate, a quartz plate, a plastic plate, etc. 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 light.

[0038] 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.

[0039] [Anode 2] An anode 2 is provided on the substrate 1 (on the hole injection layer 3 side). In the case of an organic electroluminescent device in which light is extracted through the anode, the anode is formed from a material that is transparent or substantially transparent to the emitted light.

[0040] The transparent material used for the anode is not particularly limited, but examples thereof include indium tin oxide (ITO), indium zinc oxide (IZO), 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 device configured to extract light only from the cathode side, the transmittance characteristics of the anode are not important, and therefore, examples of materials that can be used for the anode in this case include gold, iridium, molybdenum, palladium, platinum, etc. A buffer layer (electrode interface layer) may be provided on the anode.

[0041] [Hole injection layer 3, hole transport layer 5] Between the anode 2 and a 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 transporting 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 with a lower electric field.

[0042] The hole injection layer and the hole transport layer also function as electron barrier layers. 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 prevented from leaking to the hole injection layer and / or the hole transport layer due to the electron barrier present at the interface between the light-emitting layer and the hole injection layer and / or the hole transport layer. As a result, the electrons accumulate at the interface within the light-emitting layer, resulting in effects such as improved current efficiency, and an organic electroluminescent device with excellent light-emitting performance can be obtained.

[0043] The material for the hole injection layer and the hole transport layer has at least one of hole injection property, hole transport property, and electron barrier property, and may be either organic or inorganic.

[0044] Specific examples of 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 copolymers, conductive polymer oligomers (particularly thiophene oligomers), porphyrin compounds, aromatic tertiary amine compounds, styrylamine compounds, etc. Among these, porphyrin compounds, aromatic tertiary amine compounds, and styrylamine compounds are preferred, and aromatic tertiary amine compounds are particularly preferred.

[0045] 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'- Examples 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-diphenylaminostilbenzene, N-phenylcarbazole, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPD), and 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (MTDATA). Furthermore, inorganic compounds such as p-type Si and p-type SiC can also be given as examples of materials for the hole injection layer and the hole transport layer.

[0046] The hole injection layer and the hole transport layer 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 or different compositions.

[0047] [Charge generation layer 4] A charge generating layer 4 may be provided between the hole injection layer 3 and the hole transport layer 5 . The material for the charge generating layer is not particularly limited, but an example thereof is dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HAT-CN). The charge generating layer 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 or different compositions.

[0048] [Emitting layer 6] The light-emitting layer 6 is provided between the hole transport layer 5 and the electron transport layer 7 described below. Materials for the light-emitting layer include phosphorescent materials, fluorescent materials, and thermally activated delayed fluorescent materials. In the light-emitting layer, electron-hole pairs recombine, resulting in light emission.

[0049] The emissive layer can consist of a single small molecule or polymeric material, but more commonly consists of a host material doped with a guest compound. Light emission comes primarily from the dopant and can be of any color. There are two types of dopants: fluorescent and phosphorescent.

[0050] 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 specific examples 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.

[0051] Examples of fluorescent dopants include anthracene, pyrene, tetracene, xanthene, perylene, rubrene, coumarin, rhodamine, quinacridone, dicyanomethylenepyran compounds, thiopyran compounds, polymethine compounds, pyrylium, thiapyrylium compounds, fluorene derivatives, periflanthene derivatives, indenoperylene derivatives, bis(azinyl)amine boron compounds, bis(azinyl)methane compounds, carbostyril compounds, etc. The fluorescent dopant may be a combination of two or more selected from these.

[0052] Examples of phosphorescent dopants include organometallic complexes of transition metals such as iridium, platinum, palladium, and osmium.

[0053] 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)), and FIrPic (bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl)iridium(III))).

[0054] Furthermore, 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 (hole transport layer 5 or electron transport layer 7). This can further increase the current efficiency of the organic electroluminescent device.

[0055] The light-emitting layer 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 or different compositions.

[0056] [Electron transport layer 7] An electron transport layer 7 is provided between the light-emitting layer 6 and a cathode 8, which will be described later. The electron transport layer has a function of transporting 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.

[0057] As described above, the electron transport layer preferably contains the azine compound represented by the above formula (1).

[0058] The electron transport layer may further contain a conventionally known electron transport material in addition to the azine compound (1). Examples of conventionally known electron transport materials include 8-hydroxyquinolinatolithium (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)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, and bis(2-methyl-8-quinolinato)-1-naphtho. bis(2-methyl-8-quinolinato)-2-naphtholatogallium, 2-[3-(9-phenanthrenyl)-5-(3-pyridinyl)phenyl]-4,6-diphenyl-1,3,5-azine, and 2-(4,''-di-2-pyridinyl[1,1':3',1''-terphenyl]-5-yl)-4,6-diphenyl-1,3,5-azine, 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 bis(10-hydroxybenzo[h]quinolinato)beryllium).

[0059] The electron transport layer 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 or different compositions. When the electron transport layer has a two-layer structure with a first electron transport layer on the light-emitting layer side and a second electron transport layer on the cathode side, it is preferable that the second electron transport layer contains the azine compound (1).

[0060] [Cathode 8] A cathode 8 is provided on the electron transport layer 7 . In the case of an organic electroluminescence element having a configuration in which only light emitted through the anode is extracted, the cathode can be formed from any conductive material. Cathode materials include sodium, sodium-potassium alloys, magnesium, lithium, magnesium / copper mixtures, magnesium / silver mixtures, magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al2O3) mixtures, indium, lithium / aluminum mixtures, and rare earth metals. A buffer layer (electrode interface layer) may be provided on the cathode (electron transport layer side).

[0061] [How each layer is formed] Each layer except for the electrodes (anode and cathode) described above can be formed by forming the material of each layer (together with a material such as a binder resin and a solvent, if necessary) into a thin film by a known method such as vacuum deposition, spin coating, casting, or LB (Langmuir-Blodgett) method. There are no particular limitations on the thickness of each layer thus formed, and it can be selected appropriately depending on the situation, but it is usually in the range of 5 nm to 5 μm.

[0062] The anode and cathode can be formed by forming a thin film of an electrode material by a method such as vapor deposition, sputtering, etc. 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 after forming a thin film by vapor deposition, sputtering, etc.

[0063] The thickness of the anode and cathode is preferably 1 μm or less, and more preferably 10 nm or more and 200 nm or less.

[0064] The organic electroluminescent device according to one embodiment of the present invention may be used as a lamp for illumination or as an exposure light source, or as a projection device for projecting images, or as a display device for directly viewing still or moving images. When used as a display device for playing moving images, the driving method may be either a passive matrix method or an active matrix method. Furthermore, by using two or more organic electroluminescent devices according to this embodiment having different emission colors, a full-color display device can be produced.

[0065] The azine compound (1) according to one embodiment of the present invention can be synthesized by appropriately combining known reactions (for example, Suzuki-Miyaura cross-coupling reaction, etc.). [Example]

[0066] 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.

[0067] 1 H-NMR measurements were carried out using Gemini200 (Varian). The glass transition temperature was measured using a DSC7020 (manufactured by Hitachi High-Tech Science Corporation). The light-emitting characteristics of the organic electroluminescent device were evaluated by applying a direct current to the fabricated device at room temperature using a luminance meter (product name: BM-9, manufactured by Topcon Technohouse Corporation).

[0068] Synthesis Example 1 Synthesis of Compound (1-3) [ka]

[0069] Under an argon atmosphere, tetrahydrofuran (300 ml) was added to a flask containing 2-(biphenyl-4-yl)-4-chloro-6-phenyl-1,3,5-triazine (5.2 g, 15.1 mmol), 2-[4-(9-phenanthrenyl)[1,1'-biphenyl]-2-yl]-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (8.3 g, 18.2 mmol), and Pd(PPh3)4 (524 mg, 0.45 mmol). A 2 M aqueous potassium phosphate solution (23 ml, 45.4 mmol) was then added, and the mixture was stirred at 70 °C for 20 hours. After cooling to room temperature, water and toluene were added, and the mixture was separated. After distilling off the solvent under reduced pressure, water was added, and the precipitated solid was collected by suction filtration. The resulting solid was washed with water and acetone. The resulting solid was dissolved in toluene (200 ml), activated carbon (1.0 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 using a Kiriyama funnel lined with Celite, and the solvent was distilled off under reduced pressure. Compound (1-3) was recrystallized from toluene to obtain a white solid (yield: 7.7 g). The glass transition temperature was 125°C. 1 H-NMR(CDCl3)δ(ppm):8.86(d,J=8.1Hz,1H),8.80(d,J=8.8Hz,1H),8.57(d,J=1.6Hz,1H),8.38-8.41(m,4H) ,8.12(m,1H),8.00(m,1H),7.89(s,1H),7.83(dd,J=2.0Hz,8.0,1H),7.61-7.71(m,9H),7.34-7.58(m,11H).

[0070] synthesis reference Example 2: Synthesis of compound (1-94) [ka] [ka] Under an argon atmosphere, tetrahydrofuran (165 ml) was added to a flask containing 2-chloro-4-(4-chlorophenyl)-6-phenyl-1,3,5-triazine (5.00 g, 16.5 mmol), 2-[(1,1':4',1''-terphenyl)-5'-yl]-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (7.66 g, 21.5 mmol), and Pd(PPh3)4 (574 mg, 0.496 mmol). A 2 M aqueous potassium phosphate solution (24.8 ml, 49.6 mmol) was then added, and the mixture was stirred at 70°C for 19 hours. After cooling to room temperature, water and toluene were added, and the mixture was separated. The solvent was evaporated under reduced pressure, and water was added. The precipitated solid was collected by suction filtration. The resulting solid was washed with water and methanol. The obtained solid was recrystallized from toluene to obtain 2-(4-chlorophenyl)-4-phenyl-6-[(1,1':4',1''-terphenyl)-5'-yl]-1,3,5-triazine as a white solid (yield: 4.39 g). Under an argon atmosphere, tetrahydrofuran (40 mL) was added to a flask containing 2-(4-chlorophenyl)-4-phenyl-6-[(1,1':4',1''-terphenyl)-5'-yl]-1,3,5-triazine (3.00 g, 4.03 mmol), 2-naphthylboronic acid (0.902 g, 5.24 mmol), palladium acetate (18.1 mg, 0.0806 mmol), and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (X-Phos) (76.9 mg, 0.161 mmol). A 2 M aqueous potassium phosphate solution (6.05 mL, 12.1 mmol) was then added, and the mixture was stirred at 70 °C for 5 hours. The mixture was allowed to cool to room temperature, and the precipitated solid was collected by suction filtration and washed with water and acetone. The resulting solid was dissolved in toluene (20 ml), activated carbon (0.3 g) was added, and the mixture was heated and stirred at 100°C for 1 hour. The activated carbon was removed by suction filtration using a Kiriyama funnel lined with Celite, and the solvent was distilled off under reduced pressure. Compound (1-94) was recrystallized from toluene to give a white solid (yield 0.7 g). 1H-NMR(CDCl3)δ(ppm):8.54(d,J=2.4Hz,1H),8.33(d,J=8.4Hz,2H),8.21(d,J=8.8Hz,2H),7.81-7.85(m ,2H),7.68-7.78(m,6H),7.60(d,J=7.6Hz,1H),7.49-7.56(m,7H),7.30-7.45(m,6H),7.23-7.25(m,2H).

[0071] Comparative Example 1 Synthesis of Compound (ETL-1) [ka]

[0072] Under an argon atmosphere, tetrahydrofuran (100 mL) was added to a flask containing 2-(biphenyl-4-yl)-4-chloro-6-phenyl-1,3,5-triazine (3.5 g, 10.2 mmol), 2-[2,5-di(naphthalen-2-yl)phenyl]-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (5.6 g, 12.2 mmol), and Pd(PPh3)4 (235 mg, 0.20 mmol). A 2 M aqueous potassium phosphate solution (15 mL, 30.5 mmol) was then added and stirred at 70°C for 20 hours. The mixture was allowed to cool to room temperature, and the precipitated solid was collected by suction filtration. The resulting solid was washed with water and acetone. The resulting solid was dissolved in toluene (420 mL), activated carbon (0.7 g) was added, and the mixture was heated and stirred at 100°C for 1 hour. The activated carbon was removed by suction filtration using a Kiriyama funnel lined with Celite, and the solvent was removed by distillation under reduced pressure. Compound (ETL-1) was obtained as a white solid (yield: 5.3 g) by recrystallization with toluene. The glass transition temperature was 104°C. 1 H-NMR(CDCl3)δ(ppm):8.76(d,J=2.0Hz,1H),8.12-8.18(m,5H),8.00-8.09(m,7H),7.75(d,J=8.8Hz,1H) ,7.70(d,J=8.0Hz,1H),7.66(d,J=8.4Hz,1H),7.37-7.57(m,11H),7.24-7.38(m,2H),7.18-7.22(m,2H).

[0073] The solubility (g / ml-toluene) data at 100°C for the azine compounds (1-3), (1-94), and compound (ETL-1) synthesized above are shown below.

[0074] [Table 1]

[0075] It is clear that the azine compound of this example has a higher solubility than ETL-1 and has high solubility.

[0076] Next, the obtained compound was used to carry out device evaluation.

[0077] Element Example 1 (see Figure 2) (Preparation of the substrate 101 and the anode 102) A glass substrate with an indium-tin oxide (ITO) transparent electrode, patterned with a 2 mm wide stripe of ITO (110 nm thick), was prepared as a substrate with an anode on its surface. The substrate was then cleaned with isopropyl alcohol and then subjected to surface treatment using ozone and ultraviolet light.

[0078] (Preparation for vacuum deposition) After cleaning, each layer was deposited on the surface-treated substrate by vacuum deposition using a vacuum deposition method, and each layer was laminated. First, the glass substrate was placed in a vacuum deposition chamber. -4 The pressure was reduced to 100 Pa. Then, each layer was formed in the following order according to the film formation conditions.

[0079] (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 10 nm film, forming a hole injection layer 103.

[0080] (Preparation of 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-fluoren-2-amine was deposited at a rate of 0.15 nm / sec to form a 85 nm film, forming a first hole transport layer 1051.

[0081] (Fabrication of second hole transport layer 1052) Sublimation-purified N-phenyl-N-(9,9-diphenylfluoren-2-yl)-N-(1,1′-biphenyl-4-yl)amine was deposited at a rate of 0.15 nm / sec to form a film of 5 nm, thereby forming a second hole transport layer 1052 .

[0082] (Fabrication of the light-emitting layer 106) Sublimation-purified 3-(10-phenyl-9-anthryl)-dibenzofuran and 2,7-bis[N,N-di-(4-tertbutylphenyl)]amino-bisbenzofurano-9,9'-spirofluorene were mixed in a mass ratio of 95:5 to form a 20 nm film, producing the light-emitting layer 106. The film formation rate was 0.18 nm / sec.

[0083] (Fabrication 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-azine was deposited at a rate of 0.05 nm / sec to form a 6 nm film, thereby forming a first electron transport layer 1071 .

[0084] (Preparation of second electron transport layer 1072) The compound (1-3) synthesized in Synthesis Example 1 and Liq were mixed in a mass ratio of 50:50 to form a 25 nm film, thereby forming a second electron transport layer 1072. The film formation rate was 0.15 nm / sec.

[0085] (Fabrication of the 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 deposited in that order to thicknesses of 80 nm and 20 nm, respectively. The silver / magnesium deposition rate was 0.5 nm / sec, and the silver deposition rate was 0.2 nm / sec.

[0086] As a result, the light-emitting area of ​​4mm as shown in Figure 2 2 An organic electroluminescent device 100 was produced. The thickness of each film was measured using a stylus film thickness measuring instrument (DEKTAK, manufactured by Bruker).

[0087] The device was then sealed in a nitrogen atmosphere glove box with an oxygen and moisture concentration of 1 ppm or less by sealing the glass sealing cap and the film-formed substrate (device) with bisphenol F epoxy resin (manufactured by Nagase ChemteX Corporation).

[0088] 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 Technohouse Co., Ltd.). 2 The current efficiency (cd / A) and driving voltage (V) were measured when current was passed through the device. The current efficiency and driving voltage are relative values, with the result of Device Reference Example 1 described below taken as the reference value (100). The measurement results are shown in Table 2.

[0089] element reference Example 2 An organic electroluminescent device was produced and evaluated in the same manner as in Element Example 1, except that compound (1-94) was used instead of compound (1-3) in Element Example 1. The measurement results obtained are shown in Table 2. Element reference example 1 An organic electroluminescent device was prepared and evaluated in the same manner as in Element Example 1, except that the compound (ETL-1) described in JP-A-2019-534548 was used instead of the compound (1-3) in Element Example 1. The measurement results are shown in Table 2.

[0090] [ka]

[0091] [Table 2]

[0092] The azine compound according to one embodiment of the present invention can provide an organic electroluminescent device that is excellent in driving voltage, luminous efficiency, and life characteristics. [Explanation of symbols]

[0093] 1,101 boards 2,102 Anode 3,103 Hole injection layer 4,104 Charge generation layer 5,105 Hole transport layer 6,106 emitting layers 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 device

Claims

1. An azine compound represented by formula (1): 【Chemistry 1】 In formula (1), A represents any one group selected from formulas (A-1) to (A-18): 【Chemistry 2】 B represents a phenyl group; Ar １ teeth, a phenyl group or a biphenylyl group which may be substituted with one or more groups 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 teeth, It represents a 2-phenanthrenyl group, a 3-phenanthrenyl group, or a 9-phenanthrenyl group.

2. The azine compound according to claim 1, wherein Ar 2 represents a 9-phenanthrenyl group.

3. The azine compound according to claim 1 or 2, wherein A represents any one group selected from the formulae (A-1) to (A-8) and (A-10) to (A-18).

4. The azine compound according to any one of claims 1 to 3, wherein A represents any one group selected from formulas (A-1) to (A-8):

5. The azine compound according to any one of claims 1 to 4, wherein A represents any one group selected from formulas (A-2) to (A-6):

6. The azine compound according to claim 1, represented by formula (1-3), (1-15), (1-27), or (1-39). 【Transformation 3】

7. A material for organic electroluminescent devices, comprising the azine compound according to any one of claims 1 to 6.

8. An electron transport material for an organic electroluminescent device, comprising the azine compound according to any one of claims 1 to 6.

9. An organic electroluminescent device comprising the azine compound according to any one of claims 1 to 6.

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