JP2006173652A - Organic el element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high luminance light emitting element having high reliability in which uniform surface emission without uneveness is possible. <P>SOLUTION: Compounds used by this invention have high melting point and glass transition temperature, and thin films formed by deposition etc are transparent and form stable amorphous state even at a temperature higher than room temperature presenting smooth and good film quality. Accordingly, without use of binder resin, the thin films can be formed by itself. Organic EL elements using the chemical compounds in an organic compound layer, particularly preferably in electron hole injecting and transporting layer thereof provide uniform surface emission without unevenness, and high luminance can be obtained in stable manner over a long term, thus the elements excel in durability and reliability. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an organic EL (electroluminescence) device having a layer containing a compound for organic EL devices which is a tetraaryldiamine derivative.

  Conventionally, low molecular weight organic compounds that produce conductivity, charge generation, etc. when irradiated with light, that is, have optical / electronic functions, often do not have the ability to form thin films themselves. It was necessary to disperse the resin in a binder resin and to apply a thin film by coating on a substrate in a diluted state. Even when the film itself has the ability to form a thin film by a method such as vacuum deposition, the stability of the thin film is insufficient, and physical changes such as phase transition are likely to occur.

  On the other hand, a specific tetraaryldiamine compound is disclosed in Patent Document 1 as a material for forming a photosensitive layer of an electrophotographic photoreceptor, but does not suggest any use as a compound for an organic EL device.

  On the other hand, the organic EL element has a structure in which a thin film containing a fluorescent organic compound is sandwiched between a cathode and an anode, and excitons are obtained by injecting electrons and holes into the thin film and recombining them. It is an element that generates (exciton) and emits light by utilizing light emission (fluorescence / phosphorescence) when the exciton is deactivated.

The characteristics of this organic EL element are that it can emit surface light with a high luminance of about 100 to 100000 cd / m ² at a low voltage of 10 V or less, and emit light from blue to red by selecting the type of fluorescent substance. It is possible.

  However, the problems of the organic EL element are that the light emission lifetime is short, and the durability and reliability are low.

(1) Physical changes in organic compounds (appearance and growth of crystal grain boundaries cause non-uniformity of the interface, leading to deterioration of charge injection ability of the device, short circuit, and dielectric breakdown, especially with a molecular weight of 500 or less. When low molecular weight compounds are used, the appearance and growth of crystal grain boundaries occur and the film properties are remarkably reduced, and even if the interface such as ITO is rough, the appearance and growth of remarkable crystal grain boundaries occurs, resulting in luminous efficiency. (This causes a decrease in light emission, current leakage, and no light emission, and also causes dark spots, which are partially non-light emitting sites.)

(2) Oxidation / peeling of the cathode (Math, Li, Na, Al, etc. are used for the cathode as the metal having a small work function in order to facilitate the injection of electrons. When the film is formed by a wet method such as spin coating, the residual solvent and decomposition products during the film formation promote the oxidation reaction of the electrode. Therefore, peeling of the electrode occurs and dark spots are easily generated.)

(3) Low luminous efficiency and large calorific value (Because current flows through the organic compound, the organic compound must be placed under a high electric field strength, so it cannot escape from the heat generation. The element deteriorates or breaks down due to melting, crystallization, thermal decomposition, etc.)

(4) Photochemical and electrochemical changes of the organic compound layer.

As means for solving these problems, an organic EL device in which a hole injecting and transporting zone is composed of a hole injecting porphyrin compound and a hole transporting aromatic tertiary amine is disclosed in Patent Document 2 (corresponding US Patent). No. 4,720,432). Specifically, in Examples 1, 10 and 11 of Patent Document 2, a transparent anode of indium / tin oxide-coated glass, copper phthalocyanine for hole injection (PC-10) (35 nm or 37.5 nm), hole 1,1′-bis (4-di-p-tolylaminophenyl) cyclohexane (ATA-1) (35 nm or 37.5 nm) for transport, aluminum trisoxin (CO-1) for light emission and electron injection transport (CO-1) ( 60 nm), and an organic EL device formed with a Mg—Ag cathode (200 nm) is disclosed. When this element is driven at a constant current density for 500 hours, at 5 mA / cm ² , the initial output is reduced from 0.08 mW / cm ² to 0.05 mW / cm ² (a reduction rate of 37.5%) and 20 mA / cm ^2. in cm ^2, from 0.45 mW / cm ² to 0.066mW / cm ² (reduction ratio 86.7%), also in 40 mA / cm ^2, from ^{1.15mW / cm 2 <0.1mW / cm} 2 ( reduction Rate> 91.3%). Still other hole transporting aromatic tertiary amines in Examples 12 and 13, N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl (ATA-7), and N, N, N ′, N′-tetraphenyl-4,4′-diaminobiphenyl (ATA-8) (37.5 nm) is disclosed, but the former has a small initial output for the same current density, and the output The decrease is 62.5%, and the latter is reduced by 60%.

  Further, a combination of triarylamine (ATA-1) and tetraarylamine (ATA-7) is disclosed in Examples 14 and 15, but this also has a small initial output for the same current density and a large decrease in output. As can be seen from these results, the lifetime of the light emitting device has not yet reached the practical level, and in particular when driven at a high current density to obtain high output (high luminance) light emission corresponding to the practical level, the initial stage The output drop near the operation is abrupt.

  For the purpose of improving this sudden decrease in output, Patent Document 3 or Patent Document 4 discloses a hole-transporting aromatic tertiary amine particularly selected. Specifically, the compound includes at least two tertiary amine components, and the aromatic component bonded to the nitrogen atom of the tertiary amine includes at least two condensed aromatic rings. However, even if these specific hole transporting aromatic tertiary amines are used, it is very difficult to obtain stable light emission over a long period of time, and the lifetime of a light emitting device at a practical level is still insufficient. .

  This is because the hole-transporting aromatic tertiary amine specifically disclosed in the above specification or the above publication has a low thermal characteristic, and therefore, in the amorphous state due to heat generation due to the Joule heat of the element. When the thin film stability becomes insufficient and it is used in an organic EL device, the light emission efficiency is low, the light emission life is short, and the durability and reliability are considered to be lowered.

  Moreover, since the transparent electrode needs to have a low surface resistance (10 to 30Ω / □) or less, ITO glass or the like is used. However, according to observation with a scanning tunneling microscope (STM) or an atomic force microscope (AFM), there are irregularities of about 20 nm on the sputter deposition substrate and about 40 nm on the EB deposition substrate, and there is also surface roughness due to damage during ITO patterning. In an environment where crystallization of the organic thin film is easily promoted.

  In order to improve this, measures such as providing a metal-containing phthalocyanine or metal-free phthalocyanine on the ITO surface (the above-mentioned US Pat. No. 4,720,432 or the above-mentioned Patent Document 2), or spin-coating polyarylene vinylene are taken. Has been. However, metal-containing phthalocyanine and metal-free phthalocyanine are microcrystals and do not necessarily have an effect, and polyarylene vinylene damages ITO by acid during conversion, promotes oxidation of the electrode by residual solvent, spins, Since it is a non-uniform film formed by a coat, the reliability of the element was not improved.

  On the other hand, various EL devices having a mixed layer in which two or more compounds having different functions are mixed have recently been proposed for the purpose of improving device performance. For example, in Patent Document 5, for the purpose of improving luminance and durability, a thin film or a mixed thin film of an organic compound having a hole transporting ability and a light emitting function and an organic compound having an electron transporting ability is used as a light emitting layer. In addition, Patent Document 6 proposes that a thin film of a mixture of an organic compound having a hole transporting function and a fluorescent organic compound having an electron transporting function be used for the light emitting layer. Furthermore, Patent Document 7 proposes to provide a mixed layer in which a charge injection material and an organic phosphor are mixed between the charge injection layer and the light emitting layer for the purpose of improving the light emission efficiency and the light emission luminance. . Patent Document 8 discloses that a hole transport layer and / or an electron transport layer and an organic light emitting layer face each other for the purpose of facilitating injection of holes and electrons into the light emitting layer. It has been proposed to provide a mixed layer containing the constituent materials of both layers. Further, in Patent Document 9, when a plurality of organic compound layers are formed, a layer in which compounds having different functions coexist, for example, a layer containing a hole transporting light emitting material, a hole transporting light emitting material, and an electron transporting property. It has been proposed to provide a layer in which a material coexists to increase the luminance of light emission and to exhibit various emission hues and to improve durability. Further, Patent Document 10 proposes that a mixed layer composed of a light emitting substance and a charge injection substance is formed between the light emitting layer and the charge injection layer to reduce the driving voltage. Further, in Patent Document 11, the light-emitting layer is made of a thin film in which a hole-conducting organic compound and an organic complex of a rare earth metal are mixed, the emission spectrum width is narrow, the monochromaticity is excellent, and the conversion efficiency is improved. It has been proposed that Further, Patent Document 12 and Patent Document 13 provide a thin film layer in which the components of the organic light emitter thin film layer are made of a mixture of an organic charge material and an organic light emitting material, prevent concentration quenching, and widen the selection range of the light emitting material. It has been proposed to provide a high-luminance full-color element. Further, Patent Document 14 proposes to form a gradient structure layer having a concentration gradient with each component forming each layer between layers, thereby reducing drive voltage and improving durability.

  Furthermore, what uses rubrene for the organic compound layer is proposed. As an organic compound layer doped with rubrene, in an organic EL device having a hole transport layer made of a mixed film of hydrazine derivatives and a light emitting layer of tris (8-quinolinolato) aluminum as the organic compound layer, a hole transport layer In addition, rubrene is doped with rubrene, or the organic interface side half of the hole transport layer and the entire light emitting layer are doped with rubrene. When the hole transport layer is doped, light emission occurs from both tris (8-quinolinolato) aluminum and rubrene. When the hole transport layer and the light emitting layer are doped, the luminous efficiency is improved. In addition, it has been reported that an increase in dark spots during storage can be suppressed (Non-Patent Document 1, Non-Patent Document 2). Further, a triphenyldiamine derivative (TPD) hole transport layer doped with rubrene has been proposed, and it has been reported that the luminance half-life is improved (Non-patent Document 3).

  Patent Document 15 proposes an organic compound thin film layer composed of a p-type inorganic semiconductor thin film layer and a layer mainly composed of rubrene, so that sufficient emission luminance and stability of emission luminance can be obtained. It is described that

However, none of these EL elements is satisfactory in terms of improving the light emission lifetime.
JP-A-2-277071 JP-A 63-295695 US Pat. No. 5,061,569 Japanese Patent Laid-Open No. 5-234681 JP-A-2-250292 JP-A-2-291696 JP-A-3-114197 Japanese Patent Laid-Open No. 3-190088 JP-A-4-334894 JP-A-5-182762 JP-A-3-289090 JP-A-4-178487 Japanese Patent Laid-Open No. 5-78655 JP-A-4-357694 JP-A-2-207488 Kanai, Yajima, Sato, Proceedings of the 39th Joint Conference on Applied Physics, 28p-Q-8 (1992) Sato, Kanai, Organic Electronics Materials Society (JOEM) Workshop 92 Proceedings, 31 (1992) Fujii, Sano, Fujita, Hamada, Shibata, Proceedings of the 54th Applied Physics Academic Conference, 29p-ZC-7 (1993)

  The object of the present invention is to have a high melting point and a glass transition temperature, excellent thermal characteristics, and sufficiently obtain a thin film stability in an amorphous state over a long period of time. Therefore, without using a binder resin by itself. Provided is a compound for an organic EL device which is a specific tetraaryldiamine derivative having a light / electronic function which can be thinned and has little physical change, photochemical change, and electrochemical change, and this compound for organic EL device It is to realize a high-brightness organic EL element having a long light emission lifetime and high durability and reliability. In particular, it is to realize a highly reliable high-luminance light-emitting element that suppresses voltage rise and current leakage during driving of the element, appearance / growth of a partial non-light-emitting portion, and initial reduction in luminance.

Such an object is achieved by the present inventions (1) to (40) below.
(1) An organic EL device having at least one layer containing at least one compound for organic EL devices which is a tetraaryldiamine derivative represented by the following chemical formula 1.

[In the chemical formula 1, R ₁ , R ₂ , R ₃ and R ₄ each represent an aryl group, an alkyl group, an alkoxy group, an aryloxy group, an amino group or a halogen atom, and R ₁ , R ₂ , R ₃ and R _At least one of ₄ is an aryl group. r1, r2, r3 and r4 are each an integer of 0 or 1 to 5, the sum of r1, r2, r3 and r4 is an integer of 1 or more, and at least one aryl group is represented by R _{1 to} R _4. Exists. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]
(2) 2 to ₄ of R _{1 to} R ₄ are aryl groups, and at least two of these aryl groups are bonded to the para position or the meta position with respect to the bonding position of N. Organic electroluminescent element of said (1).
(3) The organic EL device according to (2), wherein at least one aryl group of R _{1 to} R ₄ is a phenyl group.
(4) The organic EL element according to any one of (1) to (3), wherein the tetraaryldiamine derivative is represented by the following chemical formula 2.

[In Chemical Formula 2, A ₁ , A ₂ , A ₃ and A ₄ are each a phenyl group bonded to the para position or the meta position with respect to the bonding position of N, and these may be the same or different. . R ₇ , R ₈ , R ₉ and R ₁₀ each represent an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, and these may be the same or different. r7, r8, r9 and r10 are each 0 or an integer of 1-4. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]
(5) The organic EL device according to (2), wherein at least one aryl group among R _{1 to} R ₄ is a naphthyl group, an anthryl group, a pyrenyl group, a perylenyl group, or a coronenyl group.
(6) The organic EL device according to (1), (2) or (5), wherein the tetraaryldiamine derivative is represented by the following chemical formula (3).

[In the chemical formula 3, Ar represents an aryl group bonded to the para position or the meta position with respect to the bonding position of N. Z ₁ , Z ₂ and Z ₃ each represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, and these may be the same or different. _However, at least one of Z 1, _{Z 2} and _{Z 3} represents an aryl group attached to the para-position or meta position with respect to the binding position of the N, _Ar, Z 1, _{Z 2} and _{Z 3} are simultaneously It does not become a phenyl group bonded to the para position or the meta position with respect to the bonding position of N. s1, s2, and s3 are each 0 or an integer of 1 to 5, and the sum of s1, s2, and s3 is an integer of 1 or more. R ₀ represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, or a halogen atom. r0 is 0 or an integer of 1 to 4, respectively. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an aryl group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]
(7) The organic EL device according to any one of (1) to (4), wherein the tetraaryldiamine derivative is represented by the following chemical formula 4.

[In the chemical formula 4, R ₇ , R ₈ , R ₉ and R ₁₀ each represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, which may be the same or different. Good. r7, r8, r9 and r10 are each 0 or an integer of 1-4. R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ each represent an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, and these may be the same or different. r11, r12, r13, and r14 are each 0 or an integer of 1-5. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]
(8) The organic EL device according to (7), wherein each of r5, r6, r7, r8, r9, r10, r11, r12, r13 and r14 is 0.
(9) The organic EL device according to any one of (1) to (4), wherein the tetraaryldiamine derivative is represented by the following chemical formula 5.

[In the chemical formula 5, R ₇ , R ₈ , R ₉ and R ₁₀ each represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, or a halogen atom, which may be the same or different. Good. r7, r8, r9 and r10 are each 0 or an integer of 1-4. R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ each represent an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, and these may be the same or different. r11, r12, r13, and r14 are each 0 or an integer of 1-5. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]
(10) The organic EL device according to (9), wherein each of r5, r6, r7, r8, r9, r10, r11, r12, r13, and r14 is 0.
(11) The organic EL device according to any one of (1) to (4), wherein the tetraaryldiamine derivative is represented by the following chemical formula 6.

[In the chemical formula 6, R ₇ , R ₈ , R ₉ and R ₁₀ each represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, or a halogen atom, which may be the same or different. Good. r7, r8, r9 and r10 are each 0 or an integer of 1-4. R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ each represent an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, and these may be the same or different. r11, r12, r13, and r14 are each 0 or an integer of 1-5. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]
(12) The organic EL device according to claim 11, wherein each of r5, r6, r7, r8, r9, r10, r11, r12, r13 and r14 is 0.
(13) The organic EL device according to any one of (1) to (4), wherein the tetraaryldiamine derivative is represented by the following chemical formula 7.

[In the chemical formula 7, R ₇ , R ₈ , R ₉ and R ₁₀ each represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, which may be the same or different. Good. r7, r8, r9 and r10 are each 0 or an integer of 1-4. R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ each represent an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, and these may be the same or different. r11, r12, r13, and r14 are each 0 or an integer of 1-5. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]
(14) The organic EL device according to (13), wherein each of r5, r6, r7, r8, r9, r10, r11, r12, r13 and r14 is 0.
(15) The organic EL device according to any one of (1) to (4), wherein the tetraaryldiamine derivative is represented by the following chemical formula 8.

[In the chemical formula 8, R ₇ , R ₈ , R ₉ and R ₁₀ each represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, or a halogen atom, which may be the same or different. Good. r7, r8, r9 and r10 are each 0 or an integer of 1-4. R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ each represent an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, and these may be the same or different. r11, r12, r13, and r14 are each 0 or an integer of 1-5. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]
(16) The organic EL device according to (15), wherein each of r5, r6, r7, r8, r9, r10, r11, r12, r13 and r14 is 0.
(17) The organic EL device according to any one of (1) to (4), wherein the tetraaryldiamine derivative is represented by the following chemical formula 9.

[In the chemical formula 9, R ₇ , R ₈ , R ₉ and R ₁₀ each represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, or a halogen atom, which may be the same or different. Good. r7, r8, r9 and r10 are each 0 or an integer of 1-4. R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ each represent an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, and these may be the same or different. r11, r12, r13, and r14 are each 0 or an integer of 1-5. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]
(18) The organic EL device according to (17), wherein each of r5, r6, r7, r8, r9, r10, r11, r12, r13 and r14 is 0.
(19) The organic EL device according to (1), (2), (5) or (6), wherein the tetraaryldiamine derivative is represented by the following chemical formula (10).

[In the chemical formula 10, Ar ₁ and Ar ₂ each represent an aryl group, and these may be the same or different. R ₁₅ and R ₁₆ each represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, or a halogen atom, and these may be the same or different. r15 and r16 are each 0 or an integer of 1-4. R ₁₇ and R ₁₈ each represent an alkyl group, an alkoxy group, an aryloxy group, an amino group, or a halogen atom, and these may be the same or different. r17 and r18 are each 0 or an integer of 1-5. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]
(20) The organic EL device according to (19), wherein each of r5, r6, r15, r16, r17 and r18 is 0.
(21) The organic EL device according to (1), (2), (5), or (6), wherein the tetraaryldiamine derivative is represented by the following chemical formula 11.

[In the formula 11, Ar ₁ and Ar ₃ each represent an aryl group, and these may be the same or different. R ₁₅ and R ₂₀ each represent an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, or a halogen atom, and these may be the same or different. r15 and r20 are each 0 or an integer of 1-4. R ₁₈ and R ₁₉ each represent an alkyl group, an alkoxy group, an aryloxy group, an amino group, or a halogen atom, and these may be the same or different. r18 and r19 are each 0 or an integer of 1-5. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]
(22) The organic EL device according to (21), wherein each of r5, r6, r15, r18, r19 and r20 is 0.
(23) The organic EL device according to (1), (2), (5) or (6), wherein the tetraaryldiamine derivative is represented by the following chemical formula (12).

[In the chemical formula 12, Ar ₁ , Ar ₂ and Ar ₃ each represent an aryl group, and these may be the same or different. R ₁₅ , R ₁₆ and R ₂₀ each represent an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, and these may be the same or different. r15, r16, and r20 are each 0 or an integer of 1-4. R ₁₈ represents an alkyl group, an alkoxy group, an aryloxy group, an amino group, or a halogen atom. r18 is 0 or an integer of 1 to 5. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]
(24) The organic EL device according to (23), wherein each of r5, r6, r15, r16, r18 and r20 is 0.
(25) The organic EL device according to (1), (2), (5) or (6), wherein the tetraaryldiamine derivative is represented by the following chemical formula (13).

[In the chemical formula 13, Ar ₄ and Ar ₅ each represent an aryl group, and these may be the same or different. R ₁₅ and R ₁₆ each represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, or a halogen atom, and these may be the same or different. r15 and r16 are each 0 or an integer of 1-4. R ₁₇ and R ₁₈ each represent an alkyl group, an alkoxy group, an aryloxy group, an amino group, or a halogen atom, and these may be the same or different. r17 and r18 are each 0 or an integer of 1-5. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]
(26) The organic EL device according to (25), wherein each of r5, r6, r15, r16, r17 and r18 is 0.
(27) The organic EL device according to the above (1), (2), (5) or (6), wherein the tetraaryldiamine derivative is represented by the following chemical formula (14).

[In the chemical formula 14, Ar ₄ and Ar ₆ each represent an aryl group, and these may be the same or different. R ₁₅ and R ₂₀ each represent an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, or a halogen atom, and these may be the same or different. r15 and r20 are each 0 or an integer of 1-4. R ₁₈ and R ₁₉ each represent an alkyl group, an alkoxy group, an aryloxy group, an amino group, or a halogen atom, and these may be the same or different. r18 and r19 are each 0 or an integer of 1-5. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]
(28) The organic EL device according to (27), wherein each of r5, r6, r15, r18, r19, and r20 is 0.
(29) The organic EL device according to (1), (2), (5) or (6), wherein the tetraaryldiamine derivative is represented by the following chemical formula (15).

[In the chemical formula 15, Ar ₄ , Ar ₅ and Ar ₆ each represent an aryl group, and these may be the same or different. R ₁₅ , R ₁₆ and R ₂₀ each represent an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, and these may be the same or different. r15, r16, and r20 are each 0 or an integer of 1-4. R ₁₈ represents an alkyl group, an alkoxy group, an aryloxy group, an amino group, or a halogen atom. r18 is 0 or an integer of 1 to 5. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]
(30) The organic EL device according to (29), wherein each of r5, r6, r15, r16, r18 and r20 is 0.
(31) Any one of the above (1) to (30), which has at least one layer containing at least one kind of the compound for an organic EL device and at least one mixture of compounds having an electron injecting and transporting function. Organic EL element.
(32) The organic EL device according to (31), wherein the compound having an electron transport function is tris (8-quinolinolato) aluminum.
(33) The organic EL device according to (31) or (32), wherein the layer containing the mixture is a light emitting layer.
(34) The organic EL device according to any one of the above (1) to (33), wherein at least one layer containing at least one of the compounds for organic EL devices is doped with a fluorescent substance.
(35) The organic EL device according to (34), wherein the fluorescent substance is rubrene.
(36) Any of (1) to (35) above, wherein the layer containing at least one of the compounds for organic EL devices is a hole injecting and transporting layer, and the hole injecting and transporting layer and the light emitting layer are included. Organic EL element.
(37) The organic EL device according to (36), wherein the hole injecting and transporting layer is composed of two or more layers having different compositions.
(38) The organic EL device according to (37), wherein at least one of the hole injection / transport layers contains polythiophene.
(39) The organic EL device according to any one of (36) to (38), which has an electron injecting and transporting layer.
(40) The layer containing at least one kind of the compound for organic EL device is a layer having a hole injection / transport function, and a layer having a light emitting function or a layer having an electron injection / transport function is provided in contact with the layer. (1) to (30), wherein a difference in ionization potential Ip between the layer having a hole injecting and transporting function and the layer having the light emitting function or the layer having an electron injecting and transporting function is 0.25 eV or more. , (34) or (35).

  The tetraaryldiamine derivative represented by Chemical Formula 1, which is a compound for organic EL elements of the present invention, has a high melting point and glass transition temperature, and the thin film formed by vapor deposition thereof is an amorphous state that is transparent and stable even at room temperature or higher. It shows a smooth and good film quality over a long period of time.

  Therefore, the film can be formed by itself without using a binder resin.

  This effect is considered due to the following.

(1) The molecular weight was increased to a high melting point.
(2) A bulky substituent such as a sterically hindered phenyl group is introduced to optimize the overlap between molecules.
(3) The number of conformations that a molecule can take is large, preventing rearrangement of molecules.

In addition, the molecule contains a lot of hole injecting and transporting units such as N-phenyl group, and introducing a phenyl group into R _{1 to} R ₄ to form a biphenyl group widens the π-conjugated system, which is advantageous for carrier movement. Also, the hole injecting and transporting ability is very excellent.

Therefore, the organic EL device of the present invention uses the tetraaryldiamine derivative represented by Chemical Formula 1 as a compound for an organic EL device in an organic compound layer, and particularly preferably in a hole injecting and transporting layer. Surface emission is possible, and high brightness can be obtained stably over a long period of time. Although it depends on the wavelength, high brightness of about 100 to 100,000 cd / m ² or more can be stably obtained. In addition, the light emission maximum wavelength of the organic EL element of this invention is about 350-700 nm.

In addition, heat resistance and durability are high, and stable driving is possible even when the element current density is about 1 A / cm ² or more.

  Furthermore, the energy level is optimized by using the organic EL device compound of the present invention in the organic compound layer, and carriers are effectively blocked at the interface, so that stable carrier recombination and light emission occur. In particular, by using the compound for an organic EL device of the present invention for a hole injecting and transporting layer, a layer having a light emitting function in contact with the hole injecting and transporting layer (a light emitting and electron injecting and transporting layer in which the light emitting layer also serves as an electron injecting and transporting layer) Or when the hole injecting and transporting layer is a layer having a hole injecting and transporting function also serving as a light emitting layer, the difference in ionization potential Ip with the electron injecting and transporting layer in contact with this layer is optimized, Since the carrier blocking effect is enhanced and the injection of carriers that are inferior or unstable in polarity is less likely to occur, the organic compound in each layer is less likely to be damaged, and the loss of carriers and excitons in the carrier recombination region and light emitting region. Live points are less likely to occur. As a result, stable light emission is obtained, and the lifetime is greatly improved.

  Further, by providing an organic compound layer in which the compound for an organic EL device of the present invention and a compound having an electron injecting and transporting function are mixed as a light emitting layer, a carrier hopping conduction path can be formed in the mixed layer. Each carrier injected into the layer travels in a more polarly dominant material. In other words, holes move in the hole injecting and transporting substance, and electrons move in the electron injecting and transporting substance. Carrier injection of the opposite polarity is less likely to occur, so that the organic compound is less likely to be damaged. The lifetime of the element is greatly improved.

  In addition, in the constitution in which the organic compound layer containing the compound for organic EL device of the present invention is doped with a fluorescent substance, the compound for organic EL device of the present invention is used for the hole injecting and transporting layer. When the layer has a light emitting function in contact with the layer (the light emitting layer includes a light emitting / electron injecting and transporting layer also serving as an electron injecting and transporting layer) or the hole injecting and transporting layer is a layer having a hole injecting and transporting function also serving as a light emitting layer In addition, the difference in ionization potential Ip with the electron injecting and transporting layer in contact with this layer is optimized, the carrier blocking effect at the interface is enhanced, and polar inferior or unstable carrier injection is less likely to occur. The compound is less likely to be damaged, and the deactivation points of carriers and excitons are less likely to be generated in the carrier recombination region and the light emitting region. In particular, when rubrene is doped as a fluorescent substance, rubrene has a bipolar transport property, and rubrene also causes carrier recombination, so that the organic compound is further damaged less. In addition, since rubrene is present in the vicinity of the carrier recombination region, energy transfer from excitons to rubrene occurs, resulting in less non-radiative deactivation, resulting in stable emission and a significant improvement in lifetime. To do.

  The compound of the present invention has a high melting point and glass transition temperature, and a thin film formed by vapor deposition or the like is transparent and forms a stable amorphous state even at room temperature or higher, showing a smooth and good film quality. Therefore, the film can be formed by itself without using a binder resin.

  In addition, the organic EL device of the present invention uses a compound for an organic EL device containing the above compound for an organic compound layer, particularly preferably a hole injecting and transporting layer, so that uniform surface emission without unevenness is possible and high luminance is achieved. It is obtained stably over a long period of time and has excellent durability and reliability.

  In particular, in the organic EL device of the present invention in which the hole injecting and transporting layer is composed of two layers, the compound of the present invention is used in one layer, and polythiophene is used in the other layer, the driving voltage and its rise can be kept low. Therefore, no dark spots are generated over a long period of time, and stable light emission can be maintained.

  Furthermore, since the organic EL element of the present invention has an element structure in which the difference in Ip is optimized, an initial decrease in luminance is suppressed and the light emission lifetime is extended.

  In addition, when rubrene is doped, the initial luminance is increased and the light emission lifetime is extended.

  Furthermore, even when a mixed layer of the compound of the present invention and a compound having an electron injecting and transporting function is used as a light emitting layer, the light emission lifetime is extended.

  Hereinafter, a specific configuration of the present invention will be described in detail.

  The compound for organic EL devices of the present invention (also referred to as “the compound of the present invention”) is a tetraaryldiamine derivative represented by Chemical Formula 1 (also referred to as “the compound of Chemical Formula 1”).

Referring to Chemical Formula 1, in Chemical Formula 1, R _{1 to} R ₄ each represents an aryl group, an alkyl group, an alkoxy group, an aryloxy group, an amino group, or a halogen atom, and at least one of R _{1 to} R ₄ Is an aryl group. r1 to r4 are each 0 or an integer of 1 to 5, and r1 to r4 are not 0 at the same time. Therefore, r1 + r2 + r3 + r4 is an integer of 1 or more, and is a number that satisfies the condition that at least one aryl group exists. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4.

The aryl group represented by R _{1 to} R ₄ may be monocyclic or polycyclic, and includes a condensed ring and a ring assembly. The total number of carbon atoms is preferably 6 to 20, and may have a substituent. Examples of the substituent in this case include an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, and a halogen atom.

Specific examples of the aryl group represented by R _{1 to} R ₄ include a phenyl group, (o-, m-, p-) tolyl group, pyrenyl group, perylenyl group, coronenyl group, naphthyl group, anthryl group, biphenylyl group. , Phenylanthryl group, tolylanthryl group and the like, and particularly preferred is a phenyl group. The aryl group, particularly the phenyl group, is bonded at the 3-position (meta position relative to the N-bonding position) or the 4-position (N It is preferable that it is a para position with respect to the bonding position.

The alkyl group represented by R _{1 to} R ₄ may be linear or branched, preferably has 1 to 10 carbon atoms, and may have a substituent. Examples of the substituent in this case are the same as those of the aryl group.

Examples of the alkyl group represented by R _{1 to} R ₄ include a methyl group, an ethyl group, a (n-, i-) propyl group, a (n-, i-, s-, t-) butyl group, and the like.

As the alkoxy group represented by R _{1 to} R ₄ , an alkyl group having 1 to 6 carbon atoms is preferable, and specific examples include a methoxy group, an ethoxy group, and a t-butoxy group. The alkoxy group may be further substituted.

Examples of the aryloxy group represented by R _{1 to} R ₄ include a phenoxy group, a 4-methylphenoxy group, and a 4- (t-butyl) phenoxy group.

The amino group represented by R _{1 to} R ₄ may be unsubstituted or may have a substituent, but preferably has a substituent, specifically a dimethylamino group, a diethylamino group, or a diphenylamino. Group, ditolylamino group, dibiphenylylamino group, N-phenyl-N-tolylamino group, N-phenyl-N-naphthylamino group, N-phenyl-N-biphenylylamino group, N-phenyl-N-anthrylamino Group, N-phenyl-N-pyrenylamino group, dinaphthylamino group, dianthrylamino group, dipyrenylamino group and the like.

Examples of the halogen atom represented by R _{1 to} R ₄ include a chlorine atom and a bromine atom.

At least one of R _{1 to} R ₄ is an aryl group, and it is particularly preferable that 2 to 4 aryl groups are present in one molecule as R _{1 to} R ₄ . It is preferable that 4 is an integer of 1 or more. In particular, 2 to 4 aryl groups are present in the molecule in total, more preferably 2 to 4 of r1 to r4 are 1, and r1 to r4 is 1, and R ₁ to R 4 are contained. All of R ₄ are preferably aryl groups. That is, there are a total of 2 to 4 aryl groups in the 4 benzene rings that may be substituted by R _{1 to} R ₄ in the molecule, and the benzene ring to which 2 to 4 aryl groups are bonded is Although it may be the same or different among the four benzene rings, it is particularly preferable that 2 to 4 aryl groups are bonded to different benzene rings. Further, it is more preferable that at least two are bonded to the para position or the meta position with respect to the bonding position of N. In this case, at least one aryl group is preferably a phenyl group, that is, it is preferable that the aryl group and the benzene ring together form a 4- or 3-biphenylyl group with respect to the N atom. It is particularly preferable that 2 to 4 are 4- or 3-biphenylyl groups. Only one or both of the 4- or 3-biphenylyl groups may be present. Further, as the aryl group other than the phenyl group, a (1-, 2-) naphthyl group, a (1-, 2-, 9-) anthryl group, a pyrenyl group, a perylenyl group, a coronenyl group, and the like are particularly preferable. In particular, the aryl group is preferably bonded to the para position or the meta position with respect to the N bonding position. These aryl groups may also be mixed with the phenyl group.

In the chemical formula 1, as the alkyl group, alkoxy group, amino group, and halogen atom represented by R ₅ and R ₆ , the same groups as those described for R _{1 to} R ₄ can be used.

  Both r5 and r6 are preferably 0, and the biphenylene group connecting two arylamino groups is preferably unsubstituted.

Note that when r1~r4 is an integer of 2 or more, each _R 1 to R ₄ each other may be the same or different in the same. Furthermore, r5, when r6 is an integer of 2 or more, _{R 5} to each other, _{R 6} to each other may be different in the same.

Among the compounds represented by Chemical formula 1, compounds represented by Chemical formula 2 or Chemical formula 3 are preferable. First, chemical formula 2 will be described. In chemical formula 2, A _{1 to} A ₄ each represents a phenyl group bonded to the para position (position 4) or the meta position (position 3) with respect to the bonding position of N, and these are the same. But it may be different. These phenyl groups may further have a substituent, and examples of the substituent in this case include the same substituents as those mentioned for the aryl group represented by R _{1 to} R ₄ . R _{7 to} R ₁₀ each represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, or a halogen atom, and these may be the same or different. Specific examples thereof include the same ones as those described for R _{1 to} R _{4 in} Chemical Formula ₁ .

  r7 to r10 are each 0 or an integer of 1 to 4, and r7 to r10 are preferably 0.

In the chemical formula 2, R ₅ , R ₆ , r5 and r6 have the same meanings as those in the chemical formula 1, and it is preferable that r5 = r6 = 0.

Incidentally, reduction in 2, when r7~r10 are each an integer of 2 or more, each _R 7 _{to R 10} each other may be different in the same.

Next, chemical formula 3 will be described. In chemical formula 3, Ar represents an aryl group bonded to the para or meta position of the bonding position of N. As an aryl group, the thing similar to what was illustrated in the place of the aryl group represented by R < ₁ > -R < ₄ > of Chemical formula ₁ can be mentioned, A phenyl group is especially preferable. In this case, the aryl group may be further substituted, and examples of such a substituent include those exemplified for R _{1 to} R ₄ . The substituent is preferably an amino group. However, the amino group may be cyclized into a heterocyclic group depending on circumstances. Specifically, it can be selected from among amino groups represented by R _{1 to} R ₄ . Z ₁ , Z ₂ and Z ₃ each represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, and these may be the same or different. Specific examples thereof include the same ones as those described for R _{1 to} R _{4 in} Chemical Formula ₁ . Provided that at least one of Z ₁ , Z ₂ and Z ₃ represents an aryl group bonded to the para- or meta-position of the bond position of N, but Ar, Z _{1 to} Z ₃ are all bonded to N at the same time. It does not become a phenyl group bonded to the para-position or meta-position with respect to the position, and preferably 2 to 3 of the four benzene rings each have one aryl group at the para-position or meta-position. Therefore, it is preferable that one or two of Z _{1 to} Z ₂ are such aryl groups. As the aryl group, a (1-, 2-) naphthyl group, a (1-, 2-, 9-) anthryl group, a pyrenyl group, a perylenyl group, a coronenyl group, and the like are preferable, but a phenyl group is most preferable.

In addition, the aryl group represented by Z _{1 to} Z ₃ may have a substituent, and examples of the substituent include those exemplified for R _{1 to} R ₄ . In particular, the substituent is preferably an amino group. Specifically, it can be selected from amino groups represented by R _{1 to} R ₄ . s1 to s3 are each 0 or an integer of 1 to 5, but they are not 0 at the same time, and the sum is an integer of 1 or more. Each of s1 to s3 is preferably 0 or 1, more preferably a combination in which one or two of s1 to s3 is 1, and the rest is 0. In this case, s1 to s3 are 1 Z _{1 to} Z ₃ included in some cases are preferably an aryl group, particularly a phenyl group, bonded to the para position or the meta position with respect to the bonding position of N.

In Chemical Formula 3, when s1 to s3 are integers of 2 or more, Z _{1 to} Z ₃ may be the same as or different from each other. In addition, R ₀ and r0 in Chemical Formula 3 have the same meanings as R ₇ and r7 in Chemical Formula 2, respectively, and R ₅ , R ₆ , r5 and r6 in Chemical Formula 3 have the same meanings as those in Chemical Formula 2, and preferred ones are also the same. It is.

Of the compounds represented by Chemical formula 2, compounds represented by Chemical formulas 4 to 9 are preferred. In each of Chemical Formulas 4 to 9, R _{11 to} R ₁₄ each represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, or a halogen atom, and these may be the same or different. Specific examples thereof are the same as those mentioned for R _{1 to} R ₄ .

  r11 to r14 are each 0 or an integer of 1 to 5, and r11 to r14 are preferably 0 in any one of Chemical Formulas 4 to 9.

Note that when r11~r14 are each an integer of 2 or more, each _R 11 _{to R 14} each other may be different in the same.

In each of Chemical Formulas 4 to 9, R _{5 to} R ₁₀ and r _{5 to} r _{10 have the same} meanings as those in Chemical Formula 2, and preferred ones are also the same.

On the other hand, among the compounds of Chemical Formula 3, compounds represented by Chemical Formulas 10 to 15 are preferable. Of each _Ar 1 to Ar ₆ shown in each of 10 of 15 represents an aryl group, of Ar ₁ and Ar ₂ of 10, of 11 of Ar ₁ and Ar _3, of 12 of Ar ₁ and Ar ₂ and Ar _3, Ar ₄ and Ar ₅ in the formula 13, and Ar ₄ and Ar ₅ and Ar ₆ in the Ar ₄ and Ar _6, of 15 of 14, may be different in each identical. Specific examples of the aryl group include the same ones as in R _{1 to} R _{4 in} Chemical Formula ₁ , and a phenyl group is particularly preferable.

Of _{R 15} of 10 of 15, of 10, of 12, of 13, of 15 of _{R 16,} Formula 11, Formula 12, Formula 14, Formula 15 in _{R 20} are each an alkyl group, an alkoxy group, an aryl group, Represents an aryloxy group, an amino group or a halogen atom, and R ₁₅ and R ₁₆ in Chemical Formula 10, Chemical Formula 13, R ₁₅ and R ₂₀ in Chemical Formula 14, Chemical Formula 12, R ₁₅ and R ₁₆ and R _{20 in} Chemical Formula ₁₅ May be the same or different. Specific examples thereof include the same ones as those described for R _{1 to} R _{4 in} Chemical Formula ₁ .

  R15 of Chemical Formula 10 to Chemical Formula 15, Chemical Formula 12, Chemical Formula 13, Chemical Formula 15 r16, Chemical Formula 11, Chemical Formula 12, Chemical Formula 14, and Chemical Formula 15 r20 are 0 or an integer of 1 to 4, r16 and r20 are preferably 0.

Of 10, of 13 of _{R 17,} of 10 of 15 of _{R 18,} Formula 11, Formula 14 in _{R 19} are each an alkyl group, an alkoxy group, an aryloxy group, an amino group or a halogen atom, of 10, of 13 of _{R 17} and _{R 18,} of 11, and _{R 18} and _{R 19} of formula 14 it may be different even in the same respectively. Specific examples thereof include the same ones as those described for R _{1 to} R _{4 in} Chemical Formula ₁ .

  R17 in Chemical Formula 10, Chemical Formula 13, r18 in Chemical Formula 10 through Chemical Formula 15, and r19 in Chemical Formula 11 and Chemical Formula 14 are 0 or an integer of 1 to 5, and r17, r18, and r19 are preferably 0.

Note that in the reduction 10 of 15, r15, r16, r20 when is an integer of 2 or _{more, R 15 together,} each other _{R 16, R 20} together may be different each be the same, r17, r18, when r19 is an integer of 2 or _more, each other _{R 17, R 18 together, R 19} each other may be the same or different in the same.

In each of Chemical Formulas 10 to 15, R ₅ , R ₆ , r5 and r6 have the same meanings as those in Chemical Formula 1, and it is preferable that r5 = r6 = 0.

Although the specific example of the compound of Chemical formula 1 is shown below, this invention is not limited to this. In addition, Chemical formula 16, Chemical formula 22, Chemical formula 27, Chemical formula 32, Chemical formula 38, Chemical formula 43, Chemical formula 49, Chemical formula 55, Chemical formula 63, Chemical formula 69, Chemical formula 75, Chemical formula 80 are general formulas, Chemical formula 17-21, Chemical formula 23 -26, Chemical 28-31, Chemical 33-37, Chemical 39-42, Chemical 44-48, Chemical 50-54, Chemical 56-62, Chemical 64-68, Chemical 70-74, Chemical 76-79, Chemical 81 Specific examples are shown by combinations of R _{1 and the} like in .about.85. In this display, except for Ar _{1 to} Ar ₆ , when all are H, it is indicated by H. When a substituent is present, only the substituent is indicated, and the other is H. ing.

  The compound of the present invention can be prepared according to or according to the method described in Jean Piccard, Herr. Chim. Acta., 7, 789 (1924), JeanPiccard, J. Am. Chem. Soc., 48, 2878 (1926), etc. Can be synthesized. Specifically, heating is performed in the presence of copper in a combination of a di (biphenyl) amine compound and a diiodobiphenyl compound, or an N, N′-diphenylbenzine compound and an iodobiphenyl compound, depending on the target compound. (Urman reaction).

  The compound of the present invention can be identified by mass spectrometry, infrared absorption spectrum (IR), 1H nuclear magnetic resonance spectrum (NMR) and the like.

  These compounds of the present invention have a molecular weight of about 640-2000, have a high melting point of 190-300 ° C., show a high glass transition temperature of 80-200 ° C., are transparent by ordinary vacuum deposition, etc. However, a stable amorphous state is formed, and a smooth and good film can be obtained and maintained for a long period of time. Note that some of the compounds of the present invention do not exhibit a melting point and exhibit an amorphous state even at high temperatures. Therefore, the film can be formed by itself without using a binder resin.

  The compounds of the present invention may be used alone or in combination of two or more.

  The organic EL device of the present invention has at least one organic compound layer, and at least one organic compound layer contains the compound for organic EL devices of the present invention. A configuration example of the organic EL element of the present invention is shown in FIG. The organic EL element 1 shown in the figure has an anode 3, a hole injection / transport layer 4, a light emitting layer 5, an electron injection / transport layer 6, and a cathode 7 in this order on a substrate 2.

  The light emitting layer has a hole and electron injection function, a transport function thereof, and a function of generating excitons by recombination of holes and electrons. It is preferable to use a relatively electronically neutral compound for the light emitting layer. The hole injecting and transporting layer has the function of facilitating the injection of holes from the anode, the function of transporting holes and the function of blocking electrons, and the electron injecting and transporting layer facilitates the injection of electrons from the cathode. These layers have the function of transporting electrons, transporting electrons, and blocking holes. These layers increase and confine holes and electrons injected into the light-emitting layer, optimize the recombination region, and emit light. Improve efficiency. The hole injecting and transporting layer and the electron injecting and transporting layer are provided as necessary in consideration of the height of each function of the hole injection, hole transport, electron injection and electron transport of the compound used for the light emitting layer. For example, when the hole injection / transport function or electron injection / transport function of the compound used in the light-emitting layer is high, the light-emitting layer is not provided with the hole injection / transport layer or the electron injection / transport layer, but the hole injection / transport layer or the electron injection It can be set as the structure which serves as a transport layer. In some cases, neither the hole injection transport layer nor the electron injection transport layer may be provided. In addition, the hole injecting and transporting layer and the electron injecting and transporting layer may be separately provided in the layer having an injection function and the layer having a transport function, respectively.

  The thickness of the light-emitting layer, the thickness of the hole injecting and transporting layer, and the thickness of the electron injecting and transporting layer are not particularly limited, and may vary depending on the formation method, but is usually about 5 to 1000 nm, and particularly 10 to 200 nm. preferable.

  The thickness of the hole injecting and transporting layer and the thickness of the electron injecting and transporting layer may be about the same as the thickness of the light emitting layer or about 1/10 to 10 times depending on the design of the recombination / light emitting region. When the injection layer and the transport layer for electrons or holes are separated, the injection layer is preferably 1 nm or more, and the transport layer is preferably 20 nm or more. In this case, the upper limit of the thickness of the injection layer and the transport layer is usually about 100 nm for the injection layer and about 1000 nm for the transport layer. Such a film thickness is the same when two injection transport layers are provided.

  In addition, the recombination region and light emission can be controlled by controlling the film thickness while considering the carrier mobility and carrier density (determined by the ionization potential and electron affinity) of the light-emitting layer, electron injection transport layer, and hole injection transport layer to be combined. The region can be designed freely, and it is possible to design the light emission color, control the light emission luminance / light emission spectrum by the interference effect of both electrodes, and control the spatial distribution of light emission.

  The compound of the present invention can be applied to both the light emitting layer and the hole injecting and transporting layer. However, since the hole injecting and transporting property is good, it is preferably used for the hole injecting and transporting layer.

  The case where the compound of the present invention is used for the hole injecting and transporting layer will be described. The hole injecting and transporting layer may be formed by depositing the compound of the present invention or by dispersing and coating it in a resin binder. In particular, a good amorphous film can be obtained by vapor deposition.

  Also, various organic compounds used in ordinary organic EL devices, for example, various organic compounds described in JP-A 63-295695, JP-A 2-191694, JP-A 3-792 and the like. A compound can be used in combination with the hole injecting and transporting layer. For example, other aromatic tertiary amine other than the compound of the present invention, hydrazone derivative, carbazole derivative, triazole derivative, imidazole derivative, oxadiazole derivative having amino group, polythiophene, etc. may be laminated or mixed with the compound of the present invention. You may do it.

  When the hole injecting and transporting layer is divided into a hole injecting layer and a hole transporting layer, a preferred combination can be selected from the compounds for the hole injecting and transporting layer. At this time, it is preferable to laminate in order of a compound layer having a small ionization potential from the anode (ITO or the like) side. Further, it is preferable to use a compound having a good thin film property on the anode surface. Such a stacking order is the same when two or more hole injection / transport layers are provided. By adopting such a stacking order, the drive voltage is lowered, and the occurrence of current leakage and the generation / growth of dark spots can be prevented. In addition, in the case of forming an element, since vapor deposition is used, a thin film of about 1 to 10 nm can be made uniform and pinhole-free, so that the ion injection potential is small in the hole injection layer and the visible portion has absorption. Even if such a compound is used, it is possible to prevent a decrease in efficiency due to a change in color tone of light emission or reabsorption.

  The organic compound used in combination with the hole injecting and transporting layer containing the compound of the present invention as a main component is preferably polythiophene, and polythiophene is deposited on the anode as a hole injecting layer having a good thin film property or a first hole injecting and transporting layer. After that, it is more preferable from the viewpoint of ionization potential to laminate the compound of the present invention as a hole transport layer or a second hole injection transport layer.

  The polythiophene that is preferably used in the present invention includes a polymer having a structural unit represented by chemical formula 88 (hereinafter, also referred to as “polymer A”), a structural unit represented by chemical formula 88, and a structural unit represented by chemical formula 89. And a polymer selected from a polymer represented by Chemical Formula 90 (hereinafter referred to as “polymer C”).

  First, the polymer A will be described. The polymer A has a structural unit of chemical formula 88, and is represented by chemical formula 91, for example.

Regarding chemical formula 88 and chemical formula 91, R ₃₁ and R ₃₂ each represent a hydrogen atom, an aromatic hydrocarbon group or an aliphatic hydrocarbon group, and these may be the same or different.

The aromatic hydrocarbon group represented by R ₃₁ and R ₃₂ may be unsubstituted or substituted, and preferably has 6 to 15 carbon atoms. Examples of the substituent when having a substituent include an alkyl group, an alkoxy group, an amino group, and a cyano group. Specific examples of the aromatic hydrocarbon group include a phenyl group, a tolyl group, a methoxyphenyl group, a biphenyl group, and a naphthyl group.

Examples of the aliphatic hydrocarbon group represented by R31 and R32 include an alkyl group and a cycloalkyl group, and these may be unsubstituted or may have a substituent. Especially, a C1-C6 thing is preferable and a methyl group, an ethyl group, i-propyl group, t-butyl group etc. are mentioned specifically ,.

R ₃₁ and R ₃₂ are preferably a hydrogen atom or an aromatic hydrocarbon group, particularly preferably a hydrogen atom.

The average degree of polymerization of the polymer A in the layer (m in Chemical Formula 91) is 4 to 100, preferably 5 to 40, and more preferably 5 to 20. In this case, even if the repeating unit represented by Chemical Formula 88 is the same polymer (homopolymer), it is a copolymer (copolymer) composed of structural units in which the combination of R ₃₁ and R ₃₂ is different in Chemical Formula 88. There may be. The copolymer may be any of a random copolymer, an alternating copolymer, a block copolymer and the like.

  Moreover, the weight average molecular weight of the polymer A in a layer is about 300-10000.

The terminal group of the polymer A (X ₁ and X _{2 in} Chemical formula 91) is a halogen atom such as a hydrogen atom, chlorine, bromine or iodine. This end group is generally introduced depending on the starting material in the synthesis of the polymer A. Furthermore, other substituents can be introduced at the final stage of the polymerization reaction.

  The polymer A is preferably composed only of the structural unit of Chemical formula 88, but may contain other monomer components as long as it is 10 mol% or less.

A specific example of polymer A is shown in Chemical formula 92. Chemical formula 92 is represented by a combination of R ₃₁ and R ₃₂ of chemical formulas 88 to 91.

  Next, the copolymer B will be described. Copolymer B has a structural unit of chemical formula 88 and a structural unit of chemical formula 89, and is represented by chemical formula 93, for example.

Chemical formula 88 is the same as that of polymer A. Therefore, R ₃₁ and R ₃₂ in Chemical formula 93 are the same as those in Chemical formula 88.

As for Chemical Formula 89, R ₃₃ and R ₃₄ each represent a hydrogen atom, an aromatic hydrocarbon group or an aliphatic hydrocarbon group, and these may be the same or different.

Specific examples of the aromatic hydrocarbon group and the aliphatic hydrocarbon group represented by R ₃₃ and R ₃₄ are the same as those described for R ₃₁ and R _{32 in} Chemical Formula 88. Moreover, the preferable thing of R _{< 33>} , R _<34 > is the same as that of R <_31> , R _<32 >. Further, R ₃₃ and R ₃₄ may be bonded to each other to form a ring and condensed to a thiophene ring. In this case, examples of the condensed ring include a benzene ring. The same applies to R ₃₃ and R ₃₄ in Chemical Formula 93.

  The average degree of polymerization of copolymer B in the layer (v + w in chemical formula 93) is 4 to 100, preferably 5 to 40, more preferably 5 to 20, as with polymer A. Further, the ratio of the structural unit of chemical formula 88 to the structural unit of chemical formula 89 is about 10/1 to 1/10 in molar ratio of the structural unit of chemical formula 88 / the structural unit of chemical formula 89.

  The weight average molecular weight of the copolymer B in the layer is about 300 to 10,000.

Further, the end groups of the copolymer B (X ₁ and X ₂ in Chemical Formula 93) are the same as those of the polymer A, and generally depend on the starting material or the ratio thereof in the synthesis of the copolymer B.

  The copolymer B is preferably composed of a structural unit of chemical formula 88 and a structural unit of chemical formula 89 as in the case of the polymer A, but if it is 10 mol% or less, it contains other monomer components. It may be. Further, the copolymer B may be any of a random copolymer, an alternating copolymer, a block copolymer, etc., and the structural formula of Chemical Formula 93 includes such a structure. Furthermore, the structural units of Chemical Formula 88 and Chemical Formula 89 may be the same or different.

A specific example of copolymer B is shown in Chemical formula 94. In the chemical formula 94, a combination of R ₃₁ and R ₃₂ of the chemical formula 88, a combination of R ₃₃ and R ₃₄ of the chemical formula 89, that is, a combination of R ₃₁ , R ₃₂ , R ₃₃ and R ₃₄ of the chemical formula 93 is shown.

Furthermore, the polymer C of Chemical formula 90 will be described. When chemical formula 90 is described, R ₃₃ and R ₃₄ have the same meanings as those of chemical formula 89, and preferred ones are also the same.

X ₁ and X ₂ may be the same as or different from each other and, like the end groups of the polymer A and the copolymer B, are hydrogen atoms or halogen atoms such as chlorine, bromine and iodine. X ₁ and X ₂ depend on the starting materials in the synthesis of polymer C.

n represents an average degree of polymerization, and is 4 to 100, preferably 5 to 40, more preferably 5 to 20 like the polymer A and the copolymer B in the layer. In this case, the combination of R ₃₃ and R ₃₄ may be the same polymer (homopolymer), or the combination of R ₃₃ and R ₃₄ may be a different copolymer (copolymer). The copolymer may be any of a random copolymer, an alternating copolymer, a block copolymer and the like.

  Moreover, the weight average molecular weight of the polymer C in a layer is about 300-10000.

  The polymer C preferably has a structure as shown in Chemical formula 90, but, similarly to the polymer A and the copolymer B, it may contain other monomer components as long as it is 10 mol% or less. .

Specific examples of the polymer C are shown in Chemical formulas 95 and 96. Chemical formula 95 is the same as chemical formula 90, and chemical formula 96 is represented by a combination of R ₃₃ and R ₃₄ of chemical formula 95.

  In the present invention, it is particularly preferable to use the polymer C among the above polymers as the polythiophene.

  Polythiophene may be used alone or in combination of two or more.

  The polythiophene used in the present invention has a melting point of 300 ° C. or higher, or has no melting point, and a high-quality film in an amorphous state or a microcrystalline state can be obtained by vacuum deposition.

  As mentioned above, when using the compound of this invention for a positive hole injection transport layer, the fluorescent material which is a compound which has a light emission function is contained in a light emitting layer. Examples of the fluorescent substance include at least one selected from compounds such as those disclosed in JP-A 63-264692, such as quinacridone, rubrene, and styryl dyes. Other examples include metal complex dyes such as tris (8-quinolinolato) aluminum, tetraphenylbutadiene, anthracene, perylene, coronene, and 12-phthaloperinone derivatives. These organic phosphors are deposited or dispersed in a resin binder and coated to form a light emitting layer with a predetermined thickness.

  For the electron injecting and transporting layer, organic metal complexes such as tris (8-quinolinolato) aluminum, oxadiazole derivatives, perylene derivatives, pyridine derivatives, pyrimidine derivatives, quinoline derivatives, quinoxaline derivatives, diphenylquinone derivatives, nitro-substituted fluorene derivatives, etc. Can be used. The electron injecting and transporting layer may also serve as the light emitting layer. In such a case, it is also preferable to use tris (8-quinolinolato) aluminum or the like. The electron injecting and transporting layer may be formed by vapor deposition or the like as with the hole injecting and transporting layer and the light emitting layer.

  When the electron injecting and transporting layer is divided into an electron injecting layer and an electron transporting layer, a preferred combination can be selected from the compounds for the electron injecting and transporting layer. At this time, it is preferable to laminate in the order of the layer of the compound having a large electron affinity value from the cathode side. Such a stacking order is the same when two or more electron injecting and transporting layers are provided.

  The organic compound layer may contain a singlet oxygen quencher.

  Such quenchers include rubrene, nickel complexes, diphenylisobenzofuran, tertiary amines and the like. Of these, rubrene is particularly preferred. The content of such a quencher is preferably 10 mol% or less of the compound of the present invention when used in combination with the compound of the present invention.

  In the present invention, it is preferable to dope rubrene into the organic compound layer.

  Doping may be performed on the entire organic compound layer, and preferably on the entire hole injecting and transporting layer. In particular, it is considered that rubrene is preferably present at the contact interface between the carrier recombination region, the light emitting region and the vicinity thereof, for example, the organic compound layer of the hole injecting and transporting layer. As a half region on the side of the light emitting layer in contact with the hole injecting and transporting layer (including the case of serving also as the electron injecting and transporting layer) or the electron injecting and transporting layer (when the hole injecting and transporting layer also serves as the light emitting layer) However, it is usually the entire hole injecting and transporting layer. In some cases, the entire region of the hole injecting and transporting layer or the hole injecting and transporting layer, a half region on the side of the light emitting layer or the electron injecting and transporting layer, and the hole injecting and transporting layer of the light emitting layer or the electron injecting and transporting layer It can also be a side half area. In particular, in the hole injecting and transporting layer, the combined use of the compound of the present invention and rubrene is preferable.

  The doping concentration of rubrene is not preferred because rubrene causes concentration quenching, and it is preferably 0.1 to 50 wt%, more preferably 0.1 to 30 wt%, particularly about the entire doping layer. It is preferable to set it as 0.1-20 wt%.

  In the present invention, in addition to rubrene, other fluorescent materials may be doped.

  Moreover, in this invention, it is preferable to provide the mixed layer containing the mixture of both compounds as a light emitting layer between the layer containing the compound of this invention, and the layer containing the compound which has another function. Furthermore, in order to increase the emission intensity, the mixed layer may be doped with a compound having a light emitting function (fluorescent substance).

  In particular, since the compound of the present invention is a compound having a hole injecting and transporting function, a layer containing a mixture with a compound having an electron injecting and transporting function (including a compound having a light emitting function) is provided as a light emitting layer. It is preferable. The compound having an electron injecting and transporting function used for the mixing can be selected from the above-mentioned compounds for electron injecting and transporting. Specifically, it is preferable to use tris (8-quinolinolato) aluminum or the like.

  Furthermore, in the mixed layer, the compounds having the hole and electron injection / transport function may be used alone or in combination of two or more, and the compound having the hole injection / transport function may be the compound of the present invention. In addition, it can be selected from the compounds for hole injection and transport described above.

  In particular, a hole injection / transport layer using the compound of the present invention is laminated on a hole injection / transport layer using polythiophene, and a mixture of both is formed between the hole injection / transport layer and the electron injection / transport layer. It is preferable to interpose the layer as a light emitting layer.

  The mixing ratio in this case depends on the carrier mobility, but the compound of the present invention is about 30 to 70 wt%, more preferably about 40 to 60 wt%, especially about 50 wt% with respect to the entire mixed layer. The weight ratio of the compound having an injecting and transporting function is preferably 30/70 to 70/30, more preferably 40/60 to 60/40, particularly about 50/50).

  Further, the thickness of the mixed layer is preferably less than the thickness of the organic compound layer from the thickness corresponding to one molecular layer, specifically 1 to 85 nm, more preferably 5 to 60 nm, In particular, the thickness is preferably 5 to 50 nm.

  In addition, as a method for forming the mixed layer, co-evaporation is preferably performed by evaporating from different evaporation sources, but when the vapor pressure (evaporation temperature) is the same or very close, the mixture is previously mixed in the same evaporation board, It can also be deposited. In the mixed layer, it is preferable that the compounds are uniformly mixed, but in some cases, the compounds may be present in an island shape.

  The mixed layer can also be used for organic compound layers other than the light emitting layer. However, it is preferable that the organic compound layer be part of the organic compound layer in the device. If all the organic compound layers are mixed layers, it may be difficult to obtain uniform emission with high luminance.

  The compound of the present invention is preferably used for a hole injecting and transporting layer, but has a difference in ionization potential Ip from a light emitting layer (including a case of also serving as an electron injecting and transporting layer) provided in contact with the hole injecting and transporting layer. It is preferably 0.25 eV or more, particularly preferably 0.25 to 0.40 eV.

  The difference in the ionization potential Ip is that when the layer containing the compound of the present invention is a layer having a hole injecting and transporting function and also functions as a light emitting layer, the layer in contact with this layer is injecting and transporting electrons. Since this is a layer, the difference from this layer is assumed.

  The absolute value of the ionization potential Ip of the compound of the present invention is about 5.0 to 5.4 eV.

  The ionization potential Ip is a single layer of 10 to 200 nm thickness using a low energy electron spectrometer “Model AC-1” (manufactured by Riken Keiki Co., Ltd.) according to the description of Shirahashi, Isobe, Uda, Electronic Materials, 123 (1985). It is the value measured using the sample which formed the vapor deposition film on the board | substrate which has an ITO transparent electrode, or a slide glass.

  The low-energy electron spectroscopy apparatus has the configuration shown in FIG.

  As shown in FIG. 2, the spectroscopic device 10 includes an ultraviolet lamp 11, a monochromator 12, a detector 13, a low energy electronic counter 14, a control device 15, a calculation display device 16, and an XY stage 17. -The sample S is mounted on the Y stage to perform measurement.

  A deuterium lamp is used as the ultraviolet lamp 11, and the light emitted from this lamp is dispersed into an arbitrary wavelength of 200 to 360 nm by the monochromator 12 and irradiated on the surface of the sample S. When light of 200 to 360 nm is converted into energy using an equation of E = hν = h (c / λ) (E: energy, h: Planck's constant, ν: frequency, λ: wavelength), each is 6.2. ~ 3.4 eV. When this light is swept from the lower excitation energy toward the higher one, electron emission due to the photoelectric effect starts at a certain energy. This energy is a value generally called a photoelectric work function. The photoelectrons thus emitted are counted using the detector 13 and the low-energy electron counting device 14, and after performing calculations such as bagland correction and correction of counting down during the dead time, as shown in FIG. Excitation energy and emitted electron quantity characteristics (basic characteristics) are displayed on the display of the arithmetic display device 16.

  As shown in the basic characteristics, the relationship between the photoemission rate (Count Per Second: CPS) and the excitation energy (eV) is as follows. The vertical axis is the nth power of the photoemission rate (CPS) n, and the horizontal axis is the excitation energy. Can be represented by a linear relationship. Here, the value of n usually adopts 1/2.

  The control device 15 performs wavelength driving of the monochromator 12, control of the sample position by the XY stage 17, and count control of the low energy electronic coefficient device 14.

  Therefore, in the present invention, the photoelectric work function obtained from FIG. 3 is defined as the ionization potential Ip.

  In addition, when the compound containing the compound of the present invention further contains another compound and the compound of the present invention is the main component (usually content of 50 wt% or more), the compound of the present invention The value of the ionization potential Ip obtained from this single-layer film is regarded as the ionization potential Ip of this layer. In addition, when two or more compounds are contained in the layer to be compared with the layer containing the compound of the present invention, the ionization obtained from the monolayer film of the compound that is the main component (usually a content of 50 wt% or more) The value of the potential Ip is regarded as the ionization potential Ip of this layer.

  The absolute value of the ionization potential Ip is smaller in the single layer film of the compound of the present invention than the single layer film of the compound to be compared.

  It should be noted that such a concept of ionization potential is not applied to a configuration in which a mixed layer is interposed.

  For the cathode, it is preferable to use a material having a low work function, such as Li, Na, Mg, Al, Ag, In, or an alloy containing one or more of these materials. Further, the cathode preferably has fine crystal grains, and particularly preferably in an amorphous state. The thickness of the cathode is preferably about 10 to 1000 nm.

In order to cause the organic EL element to emit light, at least one of the electrodes needs to be transparent or translucent, and the cathode material is limited as described above. Therefore, the transmittance of emitted light is preferably 80%. It is preferable to determine the material and thickness of the anode so as to achieve the above. Specifically, for example, ITO, SnO ₂ , Ni, Au, Pt, Pd, polypyrrole doped with a dopant, or the like is preferably used for the anode. The thickness of the anode is preferably about 10 to 500 nm. Moreover, in order to improve the reliability of an element, it is necessary for a drive voltage to be low, However As a preferable thing, 10-30 ohms / square ITO is mentioned.

  The substrate material is not particularly limited, but in the illustrated example, a transparent or translucent material such as glass or resin is used to extract emitted light from the substrate side. Further, the emission color may be controlled by using a color filter film, a color conversion film containing a fluorescent substance, or a dielectric reflection film on the substrate.

  Note that when an opaque material is used for the substrate, the stacking order shown in FIG. 1 may be reversed.

  Next, the manufacturing method of the organic EL element of this invention is demonstrated.

  The cathode and the anode are preferably formed by vapor deposition such as vapor deposition or sputtering.

  For the formation of the hole injecting and transporting layer, the light emitting layer, and the electron injecting and transporting layer, it is preferable to use a vacuum deposition method because a homogeneous thin film can be formed. When the vacuum deposition method is used, a homogeneous thin film having an amorphous state or a crystal grain size of 0.1 μm or less (usually the lower limit is about 0.001 μm) can be obtained. If the crystal grain size exceeds 0.1 μm, non-uniform light emission occurs, the drive voltage of the device must be increased, and the charge injection efficiency is also significantly reduced.

The conditions for vacuum deposition are not particularly limited, but it is preferable that the degree of vacuum is 10 ⁻³ Pa or less and the deposition rate is about 0.1 to 1 nm / sec. Moreover, it is preferable to form each layer continuously in a vacuum. If formed continuously in a vacuum, impurities can be prevented from adsorbing to the interface of each layer, so that high characteristics can be obtained. In addition, the driving voltage of the element can be lowered.

  In the case of using a vacuum deposition method for forming each of these layers, when a plurality of compounds are contained in one layer, it is preferable to co-deposit each boat containing the compounds by controlling the temperature individually. Vapor deposition may be performed. In addition, a solution coating method (spin coating, dip, casting, etc.), a Langmuir-Blodget (LB) method, or the like can also be used. In the solution coating method, the compound of the present invention may be dispersed in a matrix material such as a polymer.

  The organic EL element of the present invention is usually used as a direct current drive type EL element, but can also be alternating current driven or pulse driven. The applied voltage is usually about 2 to 20V.

  In addition, the compound of this invention is applicable to photoelectric conversion elements other than an organic EL element as an organic-semiconductor material which has donor property, for example, a photovoltaic cell, a photosensor. Furthermore, it is also useful as a thermochromic material utilizing the transition between the amorphous state and the crystal.

  Hereinafter, specific examples of the present invention will be shown together with comparative examples, and the present invention will be described in more detail.

<Example 1>
Synthesis of N, N, N ′, N′-tetra (3-biphenylyl) benzidine (Compound No. I-1) 250 g of m-nitrobiphenyl (1.26 mol), 5% Pd in a 2000 ml atmospheric pressure hydrogenation apparatus -C 12.5 g and ethanol 1250 ml were charged and a theoretical amount of hydrogen gas was absorbed at room temperature. The catalyst was removed by filtration, and the filtrate was evaporated to give 212 g of m-aminobiphenyl (yield 99.9%). Further, another batch reaction was carried out at the same scale except that 254 g (1.28 mol) of m-nitrobiphenyl was used to obtain 215 g of m-aminobiphenyl (yield 99.7%).

  A 10000 ml reaction vessel was charged with 775 ml of concentrated hydrochloric acid, 775 ml of water, and 775 g of ice, and 125 g (0.740 mol) of m-aminobiphenyl was added and suspended. To this was added dropwise a 750 ml aqueous solution of 56.3 g (0.816 mol) of sodium nitrite at 0 ° C. or lower, and then stirred at the same temperature for 50 minutes. To the obtained diazonium salt aqueous solution, 1250 ml of an aqueous solution of 185 g (1.12 mol) of potassium iodide was added dropwise at 0 ° C. or less for 1 hour. After dropping, the mixture was stirred at the same temperature for 1 hour, returned to room temperature, and stirred for 2 hours.

  The reaction solution was extracted with ethyl acetate, and the organic layer was washed with water, dried (magnesium sulfate), and the solvent was distilled off to obtain crude crystals. One batch was further reacted on the same scale, and the resulting crude crystals were combined and purified on a silica gel column with n-hexane to obtain 297 g of m-iodobiphenyl (yield 71.7% for the two batches). .

  A 2000 ml reaction vessel is charged with 140 g (0.828 mol) of m-aminobiphenyl, 232 g (0.829 mol) of m-iodobiphenyl, 63.1 g (0.457 mol) of potassium carbonate, 13.9 g of copper powder, and 800 ml of nitrobenzene. The mixture was heated to reflux for 32 hours under an air stream. After completion of the reaction, the mixture was filtered to remove insoluble matters, and the filtrate was evaporated. The obtained residue was purified by a silica gel column using n-hexane / toluene = 4/1 to obtain 44.5 g of di (3-biphenyl) amine (high purity product) (yield 16.7%).

  In a 500 ml reaction vessel, 44.5 g (0.139 mol) of di (3-biphenyl) amine, 27.6 g (0.0680 mol) of 4,4′-diiodobiphenyl, 34.3 g (0.249 mol) of potassium carbonate, copper 2.3 g of powder and 180 ml of nitrobenzene were charged and heated under reflux for 24 hours under an Ar stream. After completion of the reaction, the mixture was filtered to remove insoluble matters, and the filtrate was evaporated. The obtained residue was purified by silica gel column chromatography with n-hexane / toluene = 3/1 to obtain 30 g of primary purified N, N, N ′, N′-tetra (3-biphenylyl) benzidine (yield 55. 7%). This was recrystallized and purified with toluene to obtain a product having a purity of 99.58% 6.0 g and a product having a purity of 99.23% 5.0 g (yield 20.4%). Furthermore, sublimation purification was performed to obtain 8.0 g of a 99.99% pure product.

Mass spectrometry: m / e 792 (M +)
Infrared absorption spectrum (IR): FIG.
NMR spectrum: FIG.
Differential scanning calorimetry (DSC): melting point 207.4 ° C.
Glass transition temperature 95.8 ° C

<Example 2>
Synthesis of N, N, N ′, N′-tetra (4-biphenylyl) benzidine (Compound No. II-1) 72.5 g of 4-aminobiphenyl (0.429 mol), 120 g of 4-iodobiphenyl (0.429 mol) ), 32.6 g (0.236 mol) of potassium carbonate, 6.8 g (0.107 mol) of copper, and 430 ml of nitrobenzene, and reacted at 210 ° C. overnight. After the reaction, the reaction mixture was allowed to cool, and the copper salts were removed by filtration under reduced pressure. After washing with chloroform, the solvent of the filtrate was distilled off under reduced pressure. The residue was cooled by adding 500 ml of methanol, and the precipitated crystals were collected by filtration. When 49 g of the obtained crystals are dissolved in 250 ml of dimethylformamide (DMF) with heating and cooled with water, tribiphenylamine as a by-product precipitates, and is removed by filtration. Was filtered, washed with water, and washed with methanol.

  The obtained 35 g of water-containing crystals were recrystallized with 750 ml of toluene to obtain yellowish green flake shaped di (4-biphenyl) amine. The mother liquor was concentrated to collect secondary crystals. The yield was 19 g (yield 13.8%).

  Di (4-biphenyl) amine 15 g (0.0467 mol), 4,4'-diiodobiphenyl 9.5 g (0.0234 mol), potassium carbonate 9.7 g (0.0702 mol), copper 0.74 g (0.0117 mol) ), 76 ml of nitrobenzene were charged and reacted at 220 ° C. for 2 days. After the reaction, 750 ml of DMF was added and filtered while hot to remove copper salts, the filtrate was cooled, and the precipitated crystals were collected by filtration. The obtained 25 g of water-containing crystals were recrystallized three times with 100 times the amount of toluene, and the pale yellow crystal N, N, N ′, N′-tetra (4-biphenylyl) benzidine as the target product was obtained. Obtained (yield 9 g, yield 48.6%). Furthermore, sublimation purification was performed to obtain a product with a purity of 99.99%.

Mass spectrometry: m / e 792 (M +)
Infrared absorption spectrum (IR): FIG.
NMR spectrum: FIG.
Differential scanning calorimetry (DSC): melting point 267.7 ° C.
Glass transition temperature 131.8 ° C

<Example 3>
Synthesis of N, N′-diphenyl-N, N′-di (3-biphenylyl) benzidine (Compound No. VII-1) In a 10,000 ml reaction vessel, 155 ml of concentrated hydrochloric acid, 155 g of water and 155 g of ice were charged. 25 g (0.148 mol) of biphenyl was added and suspended. To this was added dropwise a 150 ml aqueous solution of 11.3 g (0.164 mol) of sodium nitrite at 0 ° C. or less, and then stirred at the same temperature for 50 minutes. To the obtained diazonium salt aqueous solution, a 250 ml aqueous solution of 37 g (0.223 mol) of potassium iodide was added dropwise at 0 ° C. or less for 1 hour. After dropping, the mixture was stirred at the same temperature for 1 hour, returned to room temperature, and stirred for 2 hours. The reaction solution was extracted with ethyl acetate, and the organic layer was washed with water, dried (magnesium sulfate), and the solvent was distilled off to obtain crude crystals.

  This was purified by a silica gel column with n-hexane to obtain 28 g of m-iodobiphenyl.

  In a 300 ml reaction vessel, 10 g (0.0298 mol) of N, N'-diphenylbenzidine, 25 g (0.0893 mol) of m-iodobiphenyl, 12.3 g (0.0891 mol) of potassium carbonate, 2.6 g of copper powder and 150 ml of nitrobenzene. The mixture was heated and refluxed for 24 hours under an Ar stream. After completion of the reaction, the mixture was filtered to remove insoluble matters, and the filtrate was evaporated. The obtained residue was purified by silica gel column chromatography with n-hexane / ethyl acetate = 5/1 to obtain 15 g of primary purified N, N′-diphenyl-N, N′-di (3-biphenylyl) benzidine (yield). Rate 78.8%). This was recrystallized and purified with toluene to obtain 10.6 g of a 99.9% pure product (yield 55.6%). Further sublimation purification was performed to obtain a product with a purity of 99.99%.

Mass spectrometry: m / e 640 (M +)
Infrared absorption spectrum (IR): FIG.
NMR spectrum: FIG.
Differential scanning calorimetry (DSC): melting point 189.8 ° C.
Glass transition temperature 83.6 ° C

<Example 4>
Synthesis of N, N′-diphenyl-N, N′-bis [-4 ′-(N-phenyl-N-3-methylphenylamino) biphenyl-4-yl] benzidine (Compound No. X-10) 500 ml In a reaction vessel, 33.6 g (0.10 mol) of N, N'-diphenylbenzidine, 25.0 g (0.11 mol) of m-iodotoluene, 27.6 g (0.2 mol) of potassium carbonate, 2.6 g of copper powder, nitrobenzene 200 ml was charged and refluxed for 24 hours under an Ar stream. After completion of the reaction, the mixture was filtered to remove insoluble matters, and the filtrate was evaporated. The obtained residue was purified twice using silica gel column purification with n-hexane / toluene = 1/2, and 28.10 g of N, N′-diphenyl-N [-4- (N-phenyl-N-3-methyl) was obtained. Phenylamino) biphenyl-4-yl] benzidine was obtained (42% yield).

  In a 500 ml reaction vessel, 8.1 g (0.02 mol) of 4,4′-diiodobiphenyl, N, N′-diphenyl-N [-4- (N-phenyl-N-3-methylphenylamino) biphenyl-4 -Il] Benzidine 28.1 g (0.02 mol), potassium carbonate 11.04 g (0.08 mol), copper powder 1.0 g, and nitrobenzene 100 ml were charged and heated to reflux for 24 hours under an Ar stream. After completion of the reaction, the mixture was filtered to remove insoluble matters, and the filtrate was evaporated. The obtained residue was purified by silica gel column twice with n-hexane / toluene = 2/1, and 11.62 g of high-purity N, N′-diphenyl-N, N′-bis [-4 ′-( N-phenyl-N-3-methylphenylamino) biphenyl-4-yl] benzidine was obtained (58% yield). This was recrystallized and purified with a mixed solvent of hexane and toluene to obtain 7.3 g of a light yellow transparent amorphous solid having a purity of 99.9%.

Mass spectrometry: m / e 1002 (M +)
Infrared absorption spectrum (IR): FIG.
NMR spectrum: FIG.
Differential scanning calorimetry (DSC): No melting point was observed (amorphous from the initial state).
Glass transition temperature 132 ° C

<Example 5>
Synthesis of N, N′-diphenyl-N, N′-bis [-4 ′-(N, N-di-3-biphenylylamino) biphenyl-4-yl] benzidine (Compound No. X-3) 300 ml Di (3-biphenylyl) amine 16.1 g (0.050 mol), 4,4'-diiodobiphenyl 20.3 g (0.050 mol), potassium carbonate 13.8 g (0.10 mol), copper powder 1 0.0 g and 100 ml of nitrobenzene were charged, and the mixture was heated to reflux for 24 hours under an Ar stream. After completion of the reaction, the mixture was filtered to remove insoluble matters, and the filtrate was evaporated. The obtained residue was purified on a silica gel column with n-hexane / toluene = 5/1, and 12.0 g of 4 ′-[N, N′-di (3-biphenylylamino)]-4-iodo-1, 1'-biphenyl was obtained (yield 40%).

  In a 300 ml reaction vessel, 12.0 g (0.020 mol) of 4 '-[N, N'-di (3-biphenylyl) amino] -4-iodo-1,1'-biphenyl, N, N'-diphenylbenzidine 3 0.03 g (0.009 mol), 5.52 g (0.04 mol) of potassium carbonate, 0.5 g of copper powder and 100 ml of nitrobenzene were charged, and the mixture was heated to reflux for 24 hours under an Ar stream. After completion of the reaction, the mixture was filtered to remove insoluble matters, and the filtrate was evaporated. The obtained residue was purified by silica gel column twice with toluene / n-hexane = 2/1, and 6.90 g of N, N′-diphenyl-N, N′-bis [-4 ′-(N, N -Di-3-biphenylylamino) biphenyl-4-yl] benzidine was obtained (yield 60%). This was recrystallized and purified with toluene to obtain 5.2 g of a light yellow transparent amorphous solid having a purity of 99.9%. This compound was also identified by mass spectrometry, IR, and NMR as in Example 4.

  In addition, the other compound shown by Chemical formula 16-Chemical formula 87 was also synthesize | combined according to said method, and was identified by mass spectrometry, IR, and NMR.

<Example 6>
A glass substrate having an ITO transparent electrode (anode) having a thickness of 200 nm was subjected to ultrasonic cleaning using a neutral detergent, acetone, and ethanol. The substrate was lifted from boiling ethanol, dried, washed with UV / O ₃ , fixed to the substrate holder of the vapor deposition apparatus, and decompressed to 1 × 10 ⁻⁴ Pa or less.

  Next, the compound of Example 1 was deposited to a thickness of 55 nm at a deposition rate of 0.2 nm / sec to obtain a transparent amorphous thin film. Even if this is left in a constant temperature bath of 30 ° C-100% RH and 60 ° C-90% RH, which are harsher conditions than in the atmosphere, crystallization does not occur and a stable amorphous state is maintained. High film forming ability and storage stability were exhibited. Moreover, when the ionization potential Ip of the film produced in the same manner was measured with a low energy electron spectrometer AC-1 (manufactured by Riken Keiki Co., Ltd.), it was 5.35 eV.

<Example 7>
The compounds of Example 2 and Example 3 were also tested in the same manner as in Example 6. As in Example 6, crystallization did not occur even when allowed to stand for 10 months or longer. The Ip of the deposited film was 5.36 eV and 5.38 eV, respectively.

<Example 8>
The compounds of Example 4 and Example 5 were tested in the same manner as in Example 6. As in Example 6, crystallization did not occur even after standing for 10 months or longer. Moreover, Ip of the vapor deposition film was 5.32 eV and 5.28 eV, respectively.

<Comparative Example 1>
Instead of the compound of Example 1, compound (1) N, N′-diphenyl-N, N′-di (3-methylphenyl) -4,4′-diamino-1,1′-biphenyl (melting point: 171 2 ° C., glass transition temperature: 61.3 ° C.) or Compound (2) 1,1′-bis (4-di-p-tolylaminophenyl) cyclohexane (melting point: 187.8 ° C., glass transition temperature: A thin film was prepared in the same manner as in Example 6 except that 79.9 ° C. was used, and left in a thermostatic bath at 30 ° C.-100% RH. Despite being allowed to stand under a milder environmental condition than in Examples 6 to 8, crystallization started on the third day for compound (1) and on the 30th day for compound (2).

  Moreover, when Ip was measured about the compound (1) and the compound (2) similarly to Example 6, both compound (1) and (2) was 5.40 eV.

<Example 9>
A glass substrate having an ITO transparent electrode (anode) having a thickness of 200 nm was subjected to ultrasonic cleaning using a neutral detergent, acetone, and ethanol. The substrate was lifted from boiling ethanol, dried, washed with UV / O ₃ , fixed to the substrate holder of the vapor deposition apparatus, and decompressed to 1 × 10 ⁻⁴ Pa or less.

  First, the compound of Example 1 was deposited to a thickness of 75 nm at a deposition rate of 0.2 nm / sec to form a hole injecting and transporting layer.

  Next, while maintaining the reduced pressure state, tris (8-quinolinolato) aluminum was vapor-deposited to a thickness of 50 nm at a vapor deposition rate of 0.2 nm / sec to form an electron injection transport / light-emitting layer.

  Further, while maintaining the reduced pressure state, MgAg (weight ratio 10: 1) was vapor-deposited at a vapor deposition rate of 0.2 nm / sec to a thickness of 200 nm to obtain a cathode to obtain an organic EL device.

A DC voltage was applied to the EL element, and the EL element was continuously driven at a constant current density of 10 mA / cm ² in a dry atmosphere. In the initial stage, emission of 6.5 V, 400 cd / m ² of yellow-green color (maximum emission wavelength λmax = 500 nm) was confirmed. The half-life of the luminance was 600 hours, and the drive voltage during that time was 4.0 V. Also, the Ip of the deposited film of tris (8-quinolinolato) aluminum used as the light emitting layer was 5.64 eV, The difference from the compound of Example 1 as the injection transport layer was 0.29 eV.

<Examples 10 and 11>
In Example 9, an EL device was obtained in the same manner using the compound of Example 2 or the compound of Example 3 instead of the compound of Example 1, and the characteristics were similarly examined.

<Comparative Examples 2 and 3>
In Example 9, an EL device was similarly obtained using the compound (1) or (2) of Comparative Example 1 instead of the compound of Example 1, and the characteristics were similarly examined.

  Table 1 summarizes the characteristics of Examples 9 to 11 and Comparative Examples 2 to 3.

<Examples 12 and 13>
In Example 9, an EL device was obtained in the same manner using the compound of Example 4 or Example 5 instead of the compound of Example 1, and the characteristics were examined in the same manner. Good results were shown. The difference in Ip from tris (8-quinolinolato) aluminum was 0.32 eV for the compound of Example 4 and 0.36 eV for the compound of Example 5.

<Example 14>
A glass substrate having an ITO transparent electrode (anode) having a thickness of 200 nm was subjected to ultrasonic cleaning using a neutral detergent, acetone, and ethanol. The substrate was lifted from boiling ethanol, dried, washed with UV / O ₃ , fixed to the substrate holder of the vapor deposition apparatus, and decompressed to 1 × 10 ⁻⁴ Pa or less.

  First, poly (thiophene-2,5-diyl) was deposited at a deposition rate of 0.1 nm / sec to a thickness of 20 nm to form a first hole injecting and transporting layer.

  Next, while maintaining the reduced pressure state, the compound of Example 1 was deposited at a deposition rate of 0.2 nm / sec to a thickness of 55 nm to form a second hole injecting and transporting layer.

  Further, while maintaining the reduced pressure state, tris (8-quinolinolato) aluminum was vapor-deposited to a thickness of 50 nm at a vapor deposition rate of 0.2 nm / sec to form an electron injection transport / light-emitting layer.

  Further, while maintaining the reduced pressure state, MgAg (weight ratio 10: 1) was vapor-deposited at a vapor deposition rate of 0.2 nm / sec to a thickness of 200 nm to obtain a cathode to obtain an organic EL device.

A DC voltage was applied to the EL element, and the EL element was continuously driven at a constant current density of 10 mA / cm ² in a dry atmosphere. Initially, light emission of 6.0 V, 350 cd / m ² of yellow-green color (maximum emission wavelength λmax = 500 nm) was confirmed. The luminance half-life was 1600 hours, during which the drive voltage rose 2.3 V, and there were no dark spots appearing or growing.

  After that, no current leak occurred and stable light emission was exhibited.

These results satisfactorily satisfied the requirements for application as a display, but were continuously driven at a higher current density (40 mA / cm ² ) in order to accelerate the life test. Initially, it showed a high luminance of 1400 cd / m ² , its half-life was 400 hours, and the drive voltage increase during that period was 5.0V.

<Examples 15 and 16>
In Example 14, an EL device was obtained in the same manner using the compound of Example 2 or the compound of Example 3 instead of the compound of Example 1, and the characteristics were similarly examined under the condition of a current density of 10 mA / cm ² . .

Table 2 summarizes the characteristics of Examples 14 to 16 under a current density of 10 mA / cm ² .

<Examples 17 and 18>
In Example 14, an EL device was obtained in the same manner using the compound of Example 4 or the compound of Example 5 instead of the compound of Example 1, and the characteristics were similarly examined under conditions of a current density of 10 mA / cm ² . However, in all cases, good results equivalent to or better than those of Example 14 were shown.

<Example 19>
A glass substrate having an ITO transparent electrode (anode) having a thickness of 200 nm was subjected to ultrasonic cleaning using a neutral detergent, acetone, and ethanol. The substrate was lifted from boiling ethanol, dried, washed with UV / O ₃ , fixed to the substrate holder of the vapor deposition apparatus, and decompressed to 1 × 10 ⁻⁴ Pa or less.

  First, the compound of Example 1 and rubrene were deposited to a total thickness of 75 nm at a deposition rate of 0.2 nm / sec and 0.02 nm / sec, respectively, to form a hole injecting and transporting layer.

  Next, while maintaining the reduced pressure state, tris (8-quinolinolato) aluminum was vapor-deposited to a thickness of 50 nm at a vapor deposition rate of 0.2 nm / sec to form an electron injection transport / light-emitting layer.

  Further, while maintaining the reduced pressure state, MgAg (weight ratio 10: 1) was vapor-deposited at a vapor deposition rate of 0.2 nm / sec to a thickness of 200 nm to obtain a cathode to obtain an organic EL device.

A DC voltage was applied to the EL element, and the EL element was continuously driven at a constant current density of 10 mA / cm ² in a dry atmosphere. Initially, the emission of 6.2 V, 550 cd / m ² of yellow light (maximum light emission wavelength λmax = 550 nm) was confirmed. The half-life time of the luminance was 1500 hours, during which the drive voltage rose 2.8V.

<Examples 20 and 21>
In Example 19, an EL device was obtained in the same manner using the compound of Example 2 or the compound of Example 3 instead of the compound of Example 1, and the characteristics were similarly examined.

  The characteristics of Examples 19 to 21 are summarized in Table 3.

<Examples 22 and 23>
In Example 19, an EL device was obtained in the same manner using the compound of Example 4 or the compound of Example 5 instead of the compound of Example 1, and the characteristics were similarly examined. Good results were shown.

<Example 24>
A glass substrate having an ITO transparent electrode (anode) having a thickness of 200 nm was subjected to ultrasonic cleaning using a neutral detergent, acetone, and ethanol. The substrate was lifted from boiling ethanol, dried, washed with UV / O ₃ , fixed to a substrate holder of a vacuum deposition apparatus, and the vacuum chamber was depressurized to 1 × 10 ⁻⁴ Pa or less.

  First, poly (thiophene-2,5-diyl) was deposited at a deposition rate of about 0.1 nm / sec to a thickness of about 20 nm to form a first hole injecting and transporting layer.

The vacuum chamber was then returned to the atmosphere, and the vacuum chamber was again depressurized to 1 × 10 ⁻⁴ Pa or less, and then the compound of Example 1 and rubrene were deposited at a deposition rate of 0.1-0.2 nm / sec, 0.01- Co-evaporated to a total thickness of about 55 nm at 0.02 nm / sec to form a second hole injecting and transporting layer.

  Further, while maintaining the reduced pressure state, tris (8-quinolinolato) aluminum was vapor-deposited at a vapor deposition rate of 0.1 to 0.2 nm / sec to a thickness of about 50 nm to form an electron injection transport / light-emitting layer.

  Further, while maintaining the reduced pressure state, MgAg (weight ratio 10: 1) was vapor-deposited at a vapor deposition rate of 0.2 nm / sec to a thickness of about 200 nm to form a cathode to obtain an EL element.

A DC voltage was applied to the EL element, and the EL element was continuously driven at a constant current density of 10 mA / cm ² in a dry atmosphere. In the initial stage, 6.2 V, 420 cd / m ² of yellow light emission (maximum emission wavelength λmax = 550 nm) was confirmed. The half-life time of the luminance was 2000 hours, during which the drive voltage rose 4.9V.

These results satisfactorily satisfied the requirements for application as a display, but were continuously driven at a higher current density (40 mA / cm ² ) in order to accelerate the life test. Initially, it showed a high luminance of 1490 cd / m ² , its half-life was 500 hours, and the drive voltage increase during that period was 3.5V.

<Example 25>
An EL device was obtained in the same manner as in Example 24 except that the compound of Example 4 was used instead of the compound of Example 1 used for the second hole injecting and transporting layer. The characteristics of this EL element were examined in the same manner as in Example 24. The results were as good as or better than Example 24.

<Example 26>
After a glass substrate having an ITO transparent electrode (anode) with a thickness of 200 nm is ultrasonically cleaned using a neutral detergent, acetone, and ethanol, the substrate is lifted from boiling ethanol, dried, and UV / O ₃ cleaned. The vacuum chamber was depressurized to 1 × 10 ⁻⁴ Pa or less by being fixed to the substrate holder of the vacuum evaporation apparatus.

  First, the compound of Example 1 was deposited at a deposition rate of 0.1 to 0.2 nm / sec to a thickness of about 55 nm / sec to form a hole injecting and transporting layer.

  Further, while maintaining the reduced pressure state, tris (8-quinolinolato) aluminum was co-deposited at substantially the same deposition rate (0.1 to 0.2 nm / sec) as the hole injecting and transporting material and the electron injecting and transporting material, The mixed layer was formed as a light emitting layer with a thickness of about 40 nm.

  Further, while maintaining the reduced pressure state, the electron injecting and transporting material was deposited at a deposition rate of 0.1 to 0.2 nm / sec to a thickness of about 30 nm to form an electron injecting and transporting layer.

  Further, while maintaining the reduced pressure state, MgAg (weight ratio 10: 1) was vapor-deposited at a vapor deposition rate of 0.2 nm / sec to a thickness of about 200 nm to form a cathode to obtain an EL element.

A DC voltage was applied to the EL element, and the EL element was continuously driven at a constant current density of 10 mA / cm ² in a dry atmosphere. Initially, light emission of 6.7 V, 470 cd / m ² of yellow-green color (maximum emission wavelength λmax = 500 nm) was confirmed. The luminance half-life was 2000 hours, during which the drive voltage rose 3.0V.

<Example 27>
An EL device was obtained in the same manner as in Example 26 except that the compound of Example 4 was used instead of the compound of Example 1 used for the hole injecting and transporting layer and the mixed layer (light emitting layer). When the characteristics of this EL element were examined in the same manner as in Example 26, a good result equal to or better than that in Example 26 was shown.

<Example 28>
A glass substrate having an ITO transparent electrode (anode) having a thickness of 200 nm was subjected to ultrasonic cleaning using a neutral detergent, acetone, and ethanol. The substrate was lifted from boiling ethanol, dried, washed with UV / O ₃ , fixed to a substrate holder of a vacuum deposition apparatus, and the vacuum chamber was depressurized to 1 × 10 ⁻⁴ Pa or less.

  First, poly (thiophene-2,5-diyl) was deposited at a deposition rate of about 0.1 nm / sec to a thickness of 20 nm to form a first hole injecting and transporting layer.

The vacuum chamber was then returned to the atmosphere, and the vacuum chamber was again depressurized to 1 × 10 ⁻⁴ Pa or less, and then the compound of Example 1 was deposited to a thickness of about 35 nm at a deposition rate of 0.1 to 0.2 nm / sec. And it was set as the 2nd positive hole injection transport layer.

  Further, while maintaining the reduced pressure state, tris (8-quinolinolato) aluminum was co-deposited at substantially the same deposition rate (0.1 to 0.2 nm / sec) as the second hole injecting and transporting material and the electron injecting and transporting material. Thus, the mixed layer was formed as a light emitting layer to a thickness of about 40 nm.

  Further, while maintaining the reduced pressure state, the electron injecting and transporting material was deposited at a deposition rate of 0.1 to 0.2 nm / sec to a thickness of about 30 nm to form an electron injecting and transporting layer.

  Further, while maintaining the reduced pressure state, MgAg (weight ratio 10: 1) was vapor-deposited at a vapor deposition rate of 0.2 nm / sec to a thickness of about 200 nm to form a cathode to obtain an EL element.

A DC voltage was applied to the EL element, and the EL element was continuously driven at a constant current density of 10 mA / cm ² in a dry atmosphere. Initially, light emission of 6.1 V, 350 cd / m ² of yellow green color (maximum emission wavelength λmax = 500 nm) was confirmed. The half-life time of the luminance was 3000 hours, during which the drive voltage rose 5.0V.

<Example 29>
In Example 28, an EL element was similarly obtained except that the thickness of the mixed layer was 10 nm, and the characteristics were similarly evaluated. As a result, light emission of 6.2 V, 360 cd / m ² of yellow green color (maximum light emission wavelength λmax = 500 nm) was confirmed in the initial stage. The luminance half-life was 2100 hours, during which the drive voltage rose 3.3V.

<Example 30>
An EL device was obtained in the same manner as in Example 28 except that the compound of Example 4 was used instead of the compound of Example 1 used for the second hole injecting and transporting layer and the mixed layer (light emitting layer). The characteristics of this EL element were examined in the same manner as in Example 28. The results were as good as or better than Example 28.

  In Examples 9 to 30, various EL devices were similarly obtained using one or more of the exemplified compounds of the present invention in addition to the compounds of the present invention, and the characteristics were similarly evaluated. Similar results were shown depending on the configuration of the element.

It is a side view which shows the structural example of the organic EL element of this invention. It is a block diagram which shows the structure of a low energy electron spectrometer. It is a graph which shows the relationship between excitation energy and an electron yield. 1 is an infrared absorption spectrum of the compound of the present invention in Example 1. FIG. 1 is a diagram showing an NMR spectrum of the compound of the present invention in Example 1. FIG. FIG. 4 is an infrared absorption spectrum of the compound of the present invention in Example 2. 2 is a diagram showing an NMR spectrum of the compound of the present invention in Example 2. FIG. FIG. 3 is an infrared absorption spectrum of the compound of the present invention in Example 3. 4 is a diagram showing an NMR spectrum of the compound of the present invention in Example 3. FIG. FIG. 4 is an infrared absorption spectrum of the compound of the present invention in Example 4. 4 is a diagram showing an NMR spectrum of the compound of the present invention in Example 4. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 EL element 2 Substrate 3 Anode 4 Hole injection transport layer 5 Light emitting layer 6 Electron injection transport layer 7 Cathode 10 Low energy electron spectrometer 11 Ultraviolet lamp 12 Monochromator 13 Detector 14 Low energy electron counter 15 Controller 16 Calculation display Device 17 XY stage

Claims (40)

The organic EL element which has at least 1 layer containing at least 1 sort (s) or more of the compound for organic EL elements which is a tetraaryldiamine derivative represented by following Chemical formula 1.

[In the chemical formula 1, R ₁ , R ₂ , R ₃ and R ₄ each represent an aryl group, an alkyl group, an alkoxy group, an aryloxy group, an amino group or a halogen atom, and R ₁ , R ₂ , R ₃ and R _At least one of ₄ is an aryl group. r1, r2, r3 and r4 are each an integer of 0 or 1 to 5, the sum of r1, r2, r3 and r4 is an integer of 1 or more, and at least one aryl group is represented by R _{1 to} R _4. Exists. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ] 2 to ₄ of R _{1 to} R ₄ are aryl groups, and at least two of these aryl groups are bonded to the para position or the meta position with respect to the bonding position of N. Organic EL element. The organic EL device according to claim 2, wherein at least one aryl group of R _{1 to} R ₄ is a phenyl group. The organic EL device according to claim 1, wherein the tetraaryldiamine derivative is represented by the following chemical formula 2.

[In Chemical Formula 2, A ₁ , A ₂ , A ₃ and A ₄ are each a phenyl group bonded to the para position or the meta position with respect to the bonding position of N, and these may be the same or different. . R ₇ , R ₈ , R ₉ and R ₁₀ each represent an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, and these may be the same or different. r7, r8, r9 and r10 are each 0 or an integer of 1-4. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ] The organic EL device according to claim 2, wherein at least one aryl group among R _{1 to} R ₄ is a naphthyl group, an anthryl group, a pyrenyl group, a perylenyl group, or a coronenyl group. The organic EL device according to claim 1, wherein the tetraaryldiamine derivative is represented by the following chemical formula 3.

[In the chemical formula 3, Ar represents an aryl group bonded to the para position or the meta position with respect to the bonding position of N. Z ₁ , Z ₂ and Z ₃ each represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, and these may be the same or different. _However, at least one of Z 1, _{Z 2} and _{Z 3} represents an aryl group attached to the para-position or meta position with respect to the binding position of the N, _Ar, Z 1, _{Z 2} and _{Z 3} are simultaneously It does not become a phenyl group bonded to the para position or the meta position with respect to the bonding position of N. s1, s2, and s3 are each 0 or an integer of 1 to 5, and the sum of s1, s2, and s3 is an integer of 1 or more. R ₀ represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, or a halogen atom. r0 is 0 or an integer of 1 to 4, respectively. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an aryl group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ] The organic EL device according to claim 1, wherein the tetraaryldiamine derivative is represented by the following chemical formula 4.

[In the chemical formula 4, R ₇ , R ₈ , R ₉ and R ₁₀ each represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, which may be the same or different. Good. r7, r8, r9 and r10 are each 0 or an integer of 1-4. R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ each represent an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, and these may be the same or different. r11, r12, r13, and r14 are each 0 or an integer of 1-5. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]   The organic EL device according to claim 7, wherein each of r5, r6, r7, r8, r9, r10, r11, r12, r13, and r14 is 0. The organic EL element according to claim 1, wherein the tetraaryldiamine derivative is represented by the following chemical formula (5).

[In the chemical formula 5, R ₇ , R ₈ , R ₉ and R ₁₀ each represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, or a halogen atom, which may be the same or different. Good. r7, r8, r9 and r10 are each 0 or an integer of 1-4. R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ each represent an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, and these may be the same or different. r11, r12, r13, and r14 are each 0 or an integer of 1-5. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]   The organic EL device according to claim 9, wherein each of r5, r6, r7, r8, r9, r10, r11, r12, r13, and r14 is 0. The organic EL device according to claim 1, wherein the tetraaryldiamine derivative is represented by the following chemical formula (6).

[In the chemical formula 6, R ₇ , R ₈ , R ₉ and R ₁₀ each represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, or a halogen atom, which may be the same or different. Good. r7, r8, r9 and r10 are each 0 or an integer of 1-4. R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ each represent an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, and these may be the same or different. r11, r12, r13, and r14 are each 0 or an integer of 1-5. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]   The organic EL device according to claim 11, wherein each of r5, r6, r7, r8, r9, r10, r11, r12, r13, and r14 is 0. The organic EL device according to claim 1, wherein the tetraaryldiamine derivative is represented by the following chemical formula 7.

[In the chemical formula 7, R ₇ , R ₈ , R ₉ and R ₁₀ each represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, which may be the same or different. Good. r7, r8, r9 and r10 are each 0 or an integer of 1-4. R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ each represent an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, and these may be the same or different. r11, r12, r13, and r14 are each 0 or an integer of 1-5. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]   The organic EL device according to claim 13, wherein each of r5, r6, r7, r8, r9, r10, r11, r12, r13, and r14 is 0. The organic EL device according to claim 1, wherein the tetraaryldiamine derivative is represented by the following chemical formula 8.

[In the chemical formula 8, R ₇ , R ₈ , R ₉ and R ₁₀ each represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, or a halogen atom, which may be the same or different. Good. r7, r8, r9 and r10 are each 0 or an integer of 1-4. R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ each represent an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, and these may be the same or different. r11, r12, r13, and r14 are each 0 or an integer of 1-5. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]   16. The organic EL device according to claim 15, wherein each of r5, r6, r7, r8, r9, r10, r11, r12, r13 and r14 is 0. The organic EL device according to claim 1, wherein the tetraaryldiamine derivative is represented by the following chemical formula 9.

[In the chemical formula 9, R ₇ , R ₈ , R ₉ and R ₁₀ each represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, or a halogen atom, which may be the same or different. Good. r7, r8, r9 and r10 are each 0 or an integer of 1-4. R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ each represent an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, and these may be the same or different. r11, r12, r13, and r14 are each 0 or an integer of 1-5. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]   18. The organic EL device according to claim 17, wherein each of r5, r6, r7, r8, r9, r10, r11, r12, r13, and r14 is 0. The organic EL device according to claim 1, 2, 5, or 6, wherein the tetraaryldiamine derivative is represented by the following chemical formula (10).

[In the chemical formula 10, Ar ₁ and Ar ₂ each represent an aryl group, and these may be the same or different. R ₁₅ and R ₁₆ each represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, or a halogen atom, and these may be the same or different. r15 and r16 are each 0 or an integer of 1-4. R ₁₇ and R ₁₈ each represent an alkyl group, an alkoxy group, an aryloxy group, an amino group, or a halogen atom, and these may be the same or different. r17 and r18 are each 0 or an integer of 1-5. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]   The organic EL device according to claim 19, wherein r5, r6, r15, r16, r17 and r18 are each 0. The organic EL device according to claim 1, 2, 5, or 6, wherein the tetraaryldiamine derivative is represented by the following formula 11.

[In the formula 11, Ar ₁ and Ar ₃ each represent an aryl group, and these may be the same or different. R ₁₅ and R ₂₀ each represent an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, or a halogen atom, and these may be the same or different. r15 and r20 are each 0 or an integer of 1-4. R ₁₈ and R ₁₉ each represent an alkyl group, an alkoxy group, an aryloxy group, an amino group, or a halogen atom, and these may be the same or different. r18 and r19 are each 0 or an integer of 1-5. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]   The organic EL device according to claim 21, wherein each of r5, r6, r15, r18, r19, and r20 is 0. The organic EL device according to claim 1, wherein the tetraaryldiamine derivative is represented by the following chemical formula 12.

[In the chemical formula 12, Ar ₁ , Ar ₂ and Ar ₃ each represent an aryl group, and these may be the same or different. R ₁₅ , R ₁₆ and R ₂₀ each represent an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, and these may be the same or different. r15, r16, and r20 are each 0 or an integer of 1-4. R ₁₈ represents an alkyl group, an alkoxy group, an aryloxy group, an amino group, or a halogen atom. r18 is 0 or an integer of 1 to 5. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]   24. The organic EL element according to claim 23, wherein r5, r6, r15, r16, r18 and r20 are each 0. The organic EL device according to claim 1, 2, 5, or 6, wherein the tetraaryldiamine derivative is represented by the following chemical formula (13).

[In the chemical formula 13, Ar ₄ and Ar ₅ each represent an aryl group, and these may be the same or different. R ₁₅ and R ₁₆ each represents an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, or a halogen atom, and these may be the same or different. r15 and r16 are each 0 or an integer of 1-4. R ₁₇ and R ₁₈ each represent an alkyl group, an alkoxy group, an aryloxy group, an amino group, or a halogen atom, and these may be the same or different. r17 and r18 are each 0 or an integer of 1-5. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]   26. The organic EL element according to claim 25, wherein r5, r6, r15, r16, r17 and r18 are each 0. The organic EL device according to claim 1, 2, 5, or 6, wherein the tetraaryldiamine derivative is represented by the following chemical formula (14).

[In the chemical formula 14, Ar ₄ and Ar ₆ each represent an aryl group, and these may be the same or different. R ₁₅ and R ₂₀ each represent an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, or a halogen atom, and these may be the same or different. r15 and r20 are each 0 or an integer of 1-4. R ₁₈ and R ₁₉ each represent an alkyl group, an alkoxy group, an aryloxy group, an amino group, or a halogen atom, and these may be the same or different. r18 and r19 are each 0 or an integer of 1-5. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]   28. The organic EL device according to claim 27, wherein each of r5, r6, r15, r18, r19, and r20 is 0. The organic EL device according to claim 1, 2, 5, or 6, wherein the tetraaryldiamine derivative is represented by the following chemical formula (15).

[In the chemical formula 15, Ar ₄ , Ar ₅ and Ar ₆ each represent an aryl group, and these may be the same or different. R ₁₅ , R ₁₆ and R ₂₀ each represent an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group or a halogen atom, and these may be the same or different. r15, r16, and r20 are each 0 or an integer of 1-4. R ₁₈ represents an alkyl group, an alkoxy group, an aryloxy group, an amino group, or a halogen atom. r18 is 0 or an integer of 1 to 5. R ₅ and R ₆ each represent an alkyl group, an alkoxy group, an amino group, or a halogen atom, and these may be the same or different. r5 and r6 are each 0 or an integer of 1-4. ]   30. The organic EL element according to claim 29, wherein r5, r6, r15, r16, r18 and r20 are each 0.   The organic EL device according to any one of claims 1 to 30, further comprising at least one layer containing at least one of the compounds for an organic EL device and at least one mixture of compounds having an electron injecting and transporting function.   32. The organic EL device according to claim 31, wherein the compound having an electron transport function is tris (8-quinolinolato) aluminum.   The organic EL device according to claim 31 or 32, wherein the layer containing the mixture is a light emitting layer.   The organic EL device according to any one of claims 1 to 33, wherein a fluorescent substance is doped into at least one layer containing at least one of the compounds for organic EL devices.   The organic EL device according to claim 34, wherein the fluorescent material is rubrene.   The organic EL device according to any one of claims 1 to 35, wherein the layer containing at least one kind of the compound for an organic EL device is a hole injection transport layer, and has the hole injection transport layer and the light emitting layer.   The organic EL device according to claim 36, wherein the hole injection transport layer is composed of two or more layers having different compositions.   38. The organic EL device according to claim 37, wherein at least one layer of the hole injecting and transporting layer contains polythiophene.   The organic EL device according to any one of claims 36 to 38, comprising an electron injecting and transporting layer.   The layer containing at least one of the compounds for organic EL devices is a layer having a hole injection / transport function, and a layer having a light emitting function or a layer having an electron injection / transport function is provided in contact with the layer. 36. The organic material according to claim 1, wherein a difference in ionization potential Ip between the layer having the hole injection / transport function and the layer having the light emitting function or the layer having the electron injection / transport function is 0.25 eV or more. EL element.

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