JP4364130B2 - Organic EL device - Google Patents

Description

  The present invention relates to an organic EL (electroluminescence) device, and more particularly to a device that emits light by applying an electric field to a laminated thin film made of an organic compound. More specifically, the present invention relates to an organic electroluminescence device having a low driving voltage, stable light emission, high display quality, and high heat resistance by using a specific triarylamine multimer in the hole injection layer.

  The organic EL element has a configuration in which a thin film containing a fluorescent organic compound is sandwiched between an electron injection electrode (cathode) and a hole injection electrode (anode), and electrons and holes are injected into the thin film to be recombined. This is an element that emits light by utilizing the emission of light (fluorescence / phosphorescence) when excitons are generated by the excitons and the excitons are deactivated.

The characteristics of the organic EL element are that it can emit surface light with high luminance of several hundreds to several 10000 cd / m ² at a low voltage of 10 V or less, and emits light from blue to red by selecting the type of fluorescent material. It is possible.

On the other hand, the problems of organic EL are that the light emission life is short, the storage durability and the reliability are low.
(1) Physical changes in organic compounds (non-uniform interfaces occur due to crystal domain growth, etc., causing deterioration of the hole injection ability, short-circuiting, and dielectric breakdown of the element. Especially low molecular weight compounds with a molecular weight of 500 or less If used, the appearance and growth of crystal grains will occur and the film properties will be significantly reduced, and even if the interface of ITO etc. is rough, the appearance and growth of remarkable crystal grains will occur, resulting in a decrease in luminous efficiency and current leakage. (This also causes dark spots that are partially non-light emitting parts.)
(2) Oxidation / peeling of electron injection electrodes (Na, K, Li, Mg, Ca, Al, etc. have been used as metals having a small work function in order to facilitate the injection of electrons. It reacts with moisture and oxygen in the inside, and peeling of the organic layer and the electron injection electrode occurs, making it impossible to inject holes.In particular, when a film is formed by spin coating using a polymer compound, the residual solvent at the time of film formation Moisture and decomposition products promote the oxidation reaction of the electrode, causing the electrode to peel off and causing a partial non-light emitting part.)
(3) Low luminous efficiency and high calorific value.
(Because current flows in the organic compound, the organic compound must be placed under a high electric field strength, and it cannot escape from the heat generation. Due to the heat, the element deteriorates due to melting, crystallization, thermal decomposition, etc.・ Destruction occurs.)
(4) Photochemical / electrochemical changes in the organic compound layer (such as deterioration of the organic matter caused by current flowing through the organic matter, resulting in defects such as current traps and exciton traps, increase in drive voltage, decrease in brightness, etc.) Element degradation occurs.)
Etc.

  Also, in practical light emitting devices, it is used in various environments, but especially in high temperature environments, it causes rearrangement of organic molecules such as crystallization, movement and diffusion of organic substances, which are physical changes of organic compounds, and display quality. Cause deterioration of the device and destruction of the device.

  In addition, the hole injection electrode or the electron injection electrode interface, which is the interface between the organic material and the inorganic material, particularly the interface of the hole injection electrode has a great influence on the film properties of the organic material layer during film formation. Problems such as non-uniform deposition of layers and formation of good interfaces cannot occur.

  For this reason, it has been reported that materials such as phthalocyanine, polyphenylene vinylene, polythiophene vapor deposition film, and amine multimer are used for the hole injection electrode interface of the organic EL light emitting device. However, when phthalocyanine (Patent Document 1 or Patent Document 2) is used, the phthalocyanine itself is microcrystalline and promotes crystallization of the material to be placed thereon. This is not preferable. In addition, polyphenylene vinylene uses a wet process such as spin coating, so that impurities in the air such as moisture are involved, and ionic impurities such as leaving groups are mixed when the precursor is converted, so that the electrode is oxidized quickly. This causes significant luminance deterioration and drive voltage increase.

The polythiophene vapor deposition film has a large variation in the degree of polymerization of polythiophene and the vapor deposition, and the reproducibility of good device fabrication is low. This causes problems such as inability to sufficiently modify the surface state of ITO. In addition, as an amine-based multimer, a dendrimer material (Patent Document 3), a tetraamine material (Patent Document 4), a triamine material (Patent Document 5), and the like have been reported. The uniformity and stability of the film on the hole injection electrode has not been obtained.
U.S. Pat. No. 4,720,432 JP-A 63-295695 JP-A-4-308688 US Pat. No. 4,396,627 JP-A-8-193191

An object of the present invention is to provide an organic EL device having various emission colors with high reliability and light emission efficiency, using optical and electronic functional materials with little physical change, photochemical change, and electrochemical change. That is.
In addition, using an organic thin film formed by vapor deposition of a compound that is highly amorphous and highly compatible with the hole injection electrode, the drive voltage rises and the brightness decreases when the element is driven, current leaks, and a partial non-light emitting part It is to provide an organic EL element that suppresses the appearance / growth of light, has a small decrease in luminance, has high reliability such as high heat resistance, and has high luminance.
Another object of the present invention is to provide an organic EL element having a high heat resistance with an optimum work function for a hole injection electrode and an organic material to be combined in an organic EL element using a multilayer film.
Another object of the present invention is to provide an organic EL element having high hole mobility and capable of obtaining a larger current density.

Such an object is achieved by the present inventions (1) to (11) below.
(1) An organic EL device having an organic compound layer, wherein at least one organic compound layer contains a compound having a skeleton represented by the following formula (I).

（上式（Ｉ）において、L_０は２〜４環のｏ−，ｐ−，またはｍ−フェニレン基のいずれかであって、フェニレン基の数が４環の場合にはその中間に非置換または置換基を有するアミノフェニル基を有していてもよい。また、これらのフェニレン基は置換基を有していてもよい。R₀₁、R₀₂、R₀₃、およびR₀₄ は、それぞれ、

のいずれかを表わす。ここで R₁₁、R₁₂、R₁₃、R₁₄、R₁₅、R₁₆およびR₁₇はそれぞれ、置換または非置換のアリール基を表わす。 ｒ₁、ｒ₂、ｒ₃およびｒ₄は、それぞれ、０〜５員の整数であるがｒ₁+ｒ₂+ｒ₃+ｒ₄ は１以上である。ただし、ｒ ₁ 〜ｒ ₄ が０または１、ｒ ₁ +ｒ ₂ +ｒ ₃ +ｒ ₄ が１または２であり、R ₀₁ 〜R ₀₄ が

のとき、R ₁₁ およびR ₁₂ は、トリル基を除く、置換または非置換のアリール基を表わす。）

(In the above formula (I), L ₀ is any of 2 to 4 ring o-, p-, or m-phenylene groups, and when the number of phenylene groups is 4 rings, unsubstituted Alternatively, it may have an aminophenyl group having a substituent, and these phenylene groups may have a substituent, and R ₀₁ , R ₀₂ , R ₀₃ , and R ₀₄ are respectively

Represents one of the following. Here, R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ , R ₁₅ , R ₁₆ and R ₁₇ each represent a substituted or unsubstituted aryl group. r ₁ , r ₂ , r ₃ and r ₄ are each an integer of 0 to 5 members, but r ₁ + r ₂ + r ₃ + r ₄ is 1 or more. However, r ₁ ~r ₄ is 0 or _{1, r 1 + r 2 +} r 3 + r 4 is 1 or 2, the R ₀₁ to R ₀₄

In this case, R ₁₁ and R ₁₂ represent a substituted or unsubstituted aryl group excluding the tolyl group. )

(2) The organic EL device according to (1), wherein the phenylene group represented by L ₀ is a 4,4′-biphenylene group.
(3) An organic EL device having at least two organic compound layers, wherein the organic compound layer (1) or (2) is an organic compound layer having a hole injecting and transporting function.
(4) having at least three organic compound layers including an organic compound layer having a hole injection function and an organic compound layer having a hole transport function, wherein the organic compound layer of (1) or (2) is An organic EL element which is an organic compound layer having a hole injection function.
(5) The organic EL device according to (3) or (4), wherein a light emitting layer is provided in at least one of the organic compound layers, and the light emitting layer contains a hole transporting compound and an electron transporting compound.
(6) The light emitting layer includes an organic compound layer having a hole injection function and / or an organic compound layer having a hole transport function, an organic compound layer having an electron transport function, and / or an organic compound layer having an electron injection function. (5) The organic EL element which exists between.
(7) An organic EL device comprising, on the hole injection electrode, at least (3) an organic compound layer having a hole injection / transport function, an organic compound layer having a hole transport function, a light emitting layer, and an electron injection electrode.
(8) An organic EL device having, on the hole injection electrode, at least (4) an organic compound layer having a hole injection function, a light emitting layer, and an electron injection electrode.
(9) The hole injection functional film thickness of the organic compound layer having is 100nm or more (3) either organic EL element to (8).

  In the organic EL device of the present invention, since the compound represented by the above formula (I) is used for a hole injection layer or a hole injection transport layer, the thin film property is good and uniform light emission is possible without unevenness. In addition, it is stable for over a year in the atmosphere and does not cause crystallization. In addition, to optimize the hole injection efficiency, it has both a phenylenediamine skeleton in the molecular structure, a benzidine skeleton (biphenyldiamine) to improve hole mobility, and a skeleton with diamine for multiple phenylenes. To do. In addition, it can withstand high temperature driving and emits light efficiently with low driving voltage and low driving current. Furthermore, the organic EL element of the present invention has a small increase in driving voltage during continuous driving. The emission maximum wavelength of the EL element of the present invention is about 400 to 700 nm.

  The organic EL device of the present invention has an organic compound layer, and at least one organic compound layer contains a compound having a skeleton represented by the above formula (I).

The formula (I) will be described. In the formula (I), L ₀ represents a phenylene group. The phenylene group represented by L ₀ may be o-, p-, or m-, and these may be mixed. Moreover, these phenylene groups may have a substituent. For example, the biphenylene group represented as a bicyclic phenylene group may be any of 4,4′-biphenylene group, 3,3′-biphenylene group, and 3,4′-biphenylene group. , 4′-biphenylene group is preferred. The terphenylene group represented as a tricyclic phenylene group may be any of o-, p-, and m-terphenylene groups, and in particular, a p-terphenylene group (4,4 ′, 4 ″- Terphenylene group) is preferred. The quaterphenylene group represented as a 4-ring phenylene group may contain any of o-, p-, and m-phenylene groups. A '' 4 '''-quaterphenylene group is preferred. Moreover, when it has a 4-ring phenylene group, you may have a substituted or unsubstituted phenylamino group in the middle.
The substituent in this case is the same as the following R ₁₁ and R ₁₂ .

基等が挙げられる。ここで、Ｒ₂₁およびＲ₂₂はそれぞれ、非置換または置換基を有するアリール基を表す。 R ₀₁ , R ₀₂ , R ₀₃ and R ₀₄ each represents one of Chemical _Formulas 2 ; R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ , R ₁₅ , R ₁₆ and R ₁₇ each represent an unsubstituted or substituted aryl group. The aryl group represented by R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ , R ₁₅ , R ₁₆ and R ₁₇ may be monocyclic or polycyclic and has 6 to 20 carbon atoms in total. Specific examples include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, a pyrenyl group, a perylenyl group, and an o-, m- or p-biphenyl group. These aryl groups may be further substituted. Examples of such substituents include alkyl groups having 1 to 6 carbon atoms, unsubstituted or substituted aryl groups or alkoxy groups, aryloxy groups, and

Groups and the like. Here, R ₂₁ and R ₂₂ each represents an unsubstituted or substituted aryl group.

The aryl group represented by R ₂₁ and R ₂₂ may be monocyclic or polycyclic, and preferably has 6 to 20 carbon atoms, and specifically includes a phenyl group, a naphthyl group, and an anthryl group. , A phenanthryl group, a pyrenyl group, a perylenyl group and an o-, m- or p-biphenyl group, and a phenyl group is particularly preferable. These aryl groups may be further substituted, and such a substituent represents an alkyl group having 1 to 6 carbon atoms, an unsubstituted or substituted aryl group. The alkyl group is preferably a methyl group, and the aryl group is preferably a phenyl group.

R ₁ , r ₂ , r ₃ and r ₄ each represents an integer of 0 to 5, particularly 0 to 2, and preferably 0 or 1. And r < ₁ > + r < ₂ > + r < ₃ > + r < ₄ > is 1 or more, 1-4 are especially preferable, Furthermore, 2-4 are preferable. R ₀₁ , R ₀₂ , R ₀₃ and R ₀₄ are bonded at the meta position or para position with respect to the bond position of N, and all of R ₀₁ , R ₀₂ , R ₀₃ and R ₀₄ are at the meta position, R ₀₁ , R _02, also R ₀₃ and all of R ₀₄ is the para-position or R _01, R _02, R ₀₃ and R ₀₄ are bonded to the meta position or para-position, may they be mixed. When r ₁ , r ₂ , r ₃ or r ₄ is 2 or more, R ₀₁ , R ₀₂ , R ₀₃ or R ₀₄ may be the same or different.

Preferred specific examples of such compounds are shown in the following formulas (II) to (VII).

In addition, preferred specific examples of R ₀₁ , R ₀₂ , R ₀₃ and R ₀₄ are shown in Tables 1 to 78 below. In the table, R ₀₁ , R ₀₂ , R ₀₃ and R ₀₄ are R ₁ , R ₂ , R ₃ and R ₄ , respectively, and the formula (VII) in which the phenylene group is tetracyclic and has a phenylamino group in the middle. ) _Is represented by R ₅ . Moreover, said Formula (II)-(VII) is represented as a general formula.

Moreover, the compound of this invention may have a structure as shown below.

The compound of the present invention can be synthesized, for example, by an Ullmann reaction in which a primary or secondary aromatic amine and an aromatic iodide are condensed using a catalyst such as copper. When R ₀₁ , R ₀₂ and R ₀₃ , R ₀₄ are asymmetric (biphenyl is asymmetric on both sides), R ₀₁ , R ₀₂ and R ₀₃ , R ₀₄ respectively synthesize the corresponding amine, The biphenyl moiety may be coupled last (guanine coupling, Ni (dppp) Cl _2, etc.).

Specific synthesis examples are given in the following (1) to (4). (1) uses 4,4′-diiodobiphenyl and a compound represented by formula (A), and (2) uses formula (B) and formula (C)
And asymmetric compounds represented by the formula (D) are obtained by coupling using copper as a catalyst. In (3), a compound represented by formula (E) and a compound represented by formula (F) are coupled using Ni (dppp) Cl _2, and an asymmetric compound represented by formula (G) is obtained. It has gained. In (4), the compound represented by the formula (H), the compound represented by the formula (I), the compound represented by the formula (J) and the compound represented by the formula (J) are represented by the formula (K). An asymmetric compound is obtained. Here, R ₃₀ , R ₄₁ , R ₄₅ and R ₅₀ in the following (A) to (K) are respectively synonymous with R ₀₁ , R ₀₂ , R ₀₃ and R ₀₄ in the formula (I), and R ₃₂ , R ₃₃ , R ₄₂ , R ₄₃ , R ₄₆ , R ₄₇ , R ₅₂ and R ₅₃ have the same meanings as R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ , R ₁₅ , R ₁₆ and R ₁₇ in formula (I), respectively. It is.

The compound of the present invention can be identified by mass spectrometry, infrared absorption spectrum (IR), ¹ H, ¹³ C 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, a stable and uniform thin film can be obtained by itself without using a binder resin.

By using the compound of the present invention, the hole mobility is improved and the current density of the device is increased. The preferable hole mobility obtained by the compound of the present invention is 1.0 × 10 ⁻³ cm ² / Vs or more, particularly 1.1 × 10 ^{−3 to} 100 × 10 ⁻³ cm ² / Vs, 1 × 10 ^{−3 to} 20.0 × 10 ⁻³ cm ² / Vs. Moreover, it is preferable that the hole mobility in a light emitting layer is 1/2 or less of this invention compound, especially 1 / 4-1 / 1000, Furthermore, it is about 1 / 4-1 / 100 grade. Since the hole mobility is thus excellent, when the hole injection layer is formed from the compound of the present invention, the device can be operated without any problem even when the film thickness is 100 nm or more, particularly 200 nm or more. The upper limit is not particularly limited, but is usually about 5000 nm. In practice, the film thickness may be set in consideration of the optical refractive index of each layer so that light extraction is optimal and there is no problem in viewing angle and the like.
The compounds of the present invention may be used alone or in combination of two or more.

  The EL device of the present invention has at least one organic compound layer, and at least one organic compound layer contains the compound of the present invention. A configuration example of the organic EL element of the present invention is shown in FIG. The organic EL device shown in the figure has a hole injection electrode 3, a hole injection / transport layer 4, a light emitting layer 5, an electron injection transport layer 6, and an electron injection electrode 7, and a color filter on the glass substrate 2. 8. An organic EL color display is obtained by sequentially laminating and forming the fluorescence conversion filter 9, the organic EL element, the sealing layer 10, and the cover 11.

  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. The hole injecting and transporting layer has a function of facilitating hole injection from the hole injecting electrode, a function of stably transporting holes, and a function of hindering electron transport. Has the function of facilitating the injection of electrons, the function of stably transporting electrons, and the function of preventing the transport of holes. These layers increase and confine holes and electrons injected into the light-emitting layer, and recombine. Optimize the area and improve the luminous efficiency. The electron injecting and transporting layer and the hole injecting and transporting layer are provided as necessary in consideration of the height of each function of the electron injection, electron transport, hole injection, and hole transport of the compound used for the light emitting layer. For example, when the hole injecting and transporting function or electron injecting and transporting function of a compound used in the light emitting layer is high, the light emitting layer is not provided with the hole injecting and transporting layer or the electron injecting and transporting layer without providing the hole injecting and transporting layer or the electron injecting and transporting layer. It can be set as the structure which serves also. In some cases, neither the hole injection transport layer nor the electron injection transport layer may be provided. Further, 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.

  In addition, the recombination region 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, the electron injection transport layer, the hole injection transport layer, etc. The light emitting area can be set freely, and the design of the light emission color, the control of the light emission luminance and light emission spectrum by the interference effect of both electrodes, and the control of the light emission spatial distribution can be made possible.

  The compound of the present invention can be applied to any of a hole injection layer, a hole transport layer, a light-emitting layer, and a hole injection transport layer. However, since the hole injection property is good, the hole injection layer or the hole injection transport layer, particularly It is preferable to use it for the hole injection layer.

  The compound of the present invention has both a phenylene diamine skeleton and a diamine skeleton having a plurality of phenylenes such as a benzidine skeleton, so that the heat resistance is not sacrificed, and the ionization potential and carrier mobility can be freely controlled. Hole injection efficiency can be optimized.

  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.

  When the compound of the present invention is used for the hole injecting and transporting layer, the fluorescent substance used for the light emitting layer may be selected from those having longer wavelength fluorescence. For example, in combination with the compound of the present invention in the light emitting layer described above. What is necessary is just to select suitably from 1 or more types of the fluorescent substance made. In such a case, the compound of the present invention can also be used for the light emitting layer.

  In this case, the compound of the present invention can also be used. However, since the compound of the present invention has a phenylenediamine skeleton, the donor property is very strong and causes an interaction that causes a decrease in fluorescence intensity of the light emitting material and the exciplex. Cheap. For this reason, it is not preferable because a bad effect such as a decrease in the light emission rate and a decrease in color purity due to the broadening of the emission spectrum occurs. However, when a light emitting material having no interaction is used, it can be used as a hole transport material.

  One or more hole injection / transport materials may be combined with the hole injection / transport layer. In particular, it is preferable to stack the hole transport material to be combined on the ITO in order of increasing ionization potential, for example, with a hole injection layer and a hole transport layer, and the ITO surface has good thinness and hydrophilicity variation. It is preferable to use a hole injection material that can form a uniform thin film even on the ITO surface. In the case of forming an element, since vapor deposition can be used, a thin film of about 1 to 10 nm can be made uniform and pinhole-free. Further, by adjusting the film thickness, the refractive index, and the like, it is possible to prevent a decrease in efficiency by using an interference light effect such as a light emission color, light emission luminance, and light emission spatial distribution.

  Further, the hole transport layer facing the light-emitting layer has a benzidine which does not easily interact with the light-emitting materials disclosed in Japanese Patent Laid-Open Nos. 63-295695, 5-234811, and 7-43564. It is preferable to use a triarylamine multimer having only a skeleton.

  In the present invention, the light emitting layer may contain a fluorescent material. Examples of such a 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. Further, quinoline derivatives such as metal complex dyes having 8-quinolinol or a derivative thereof such as tris (8-quinolinolato) aluminum as a ligand, tetraphenylbutadiene, anthracene, perylene, coronene, 12-phthaloperinone derivatives, and the like can be given. Furthermore, a phenylanthracene derivative of Japanese Patent Application No. 6-110569, a tetraarylethene derivative of Japanese Patent Application No. 6-114456, and the like are also included.

  Further, it is preferably used in combination with a host material capable of emitting light by itself, and is preferably used as a dopant. In such a case, the content of the compound in the light emitting layer is preferably 0.01 to 10 wt%, more preferably 0.1 to 5 wt%. When used in combination with a host material, the emission wavelength characteristic of the host material can be changed, light emission shifted to a longer wavelength can be achieved, and the light emission efficiency and stability of the device can be improved.

  The host material is preferably a quinolinolato complex, and more preferably an aluminum complex having 8-quinolinol or a derivative thereof as a ligand. Examples of such aluminum complexes are those disclosed in JP-A-63-264692, JP-A-3-255190, JP-A-5-70733, JP-A-5-258859, JP-A-6-215874, and the like. Can be mentioned.

  Specifically, first, tris (8-quinolinolato) aluminum, bis (8-quinolinolato) magnesium, bis (benzo {f} -8-quinolinolato) zinc, bis (2-methyl-8-quinolinolato) aluminum oxide, tris (8-quinolinolato) indium, tris (5-methyl-8-quinolinolato) aluminum, 8-quinolinolatolithium, tris (5-chloro-8-quinolinolato) gallium, bis (5-chloro-8-quinolinolato) calcium, 5,7-dichloro-8-quinolinolato aluminum, tris (5,7-dibromo-8-hydroxyquinolinolato) aluminum, poly [zinc (II) -bis (8-hydroxy-5-quinolinyl) methane], Etc.

  In addition to 8-quinolinol or a derivative thereof, an aluminum complex having another ligand may be used, and examples thereof include bis (2-methyl-8-quinolinolato) (phenolato) aluminum (III). Bis (2-methyl-8-quinolinolato) (ortho-cresolato) aluminum (III), bis (2-methyl-8-quinolinolato) (meta-cresolato) aluminum (III), bis (2-methyl-8-quinolinolato) ( Para-cresolato) aluminum (III), bis (2-methyl-8-quinolinolato) (ortho-phenylphenolato) aluminum (III), bis (2-methyl-8-quinolinolato) (meta-phenylphenolato) aluminum ( III), bis (2-methyl-8-quinolinolato) (para-phenylphenolato) aluminum (III), bis (2- Til-8-quinolinolato) (2,3-dimethylphenolato) aluminum (III), bis (2-methyl-8-quinolinolato) (2,6-dimethylphenolato) aluminum (III), bis (2-methyl-) 8-quinolinolato) (3,4-dimethylphenolato) aluminum (III), bis (2-methyl-8-quinolinolato) (3,5-dimethylphenolato) aluminum (III), bis (2-methyl-8- Quinolinolato) (3,5-di-tert-butylphenolato) aluminum (III), bis (2-methyl-8-quinolinolato) (2,6-diphenylphenolato) aluminum (III), bis (2-methyl- 8-quinolinolato) (2,4,6-triphenylphenolato) aluminum (III), bis (2-methyl-8-quinolinolato) (2,3,6-trimethylphenolato) aluminum Ni (III), bis (2-methyl-8-quinolinolato) (2,3,5,6-tetramethylphenolato) aluminum (III), bis (2-methyl-8-quinolinolato) (1-naphtholato) aluminum (III), bis (2-methyl-8-quinolinolato) (2-naphtholato) aluminum (III), bis (2,4-dimethyl-8-quinolinolato) (ortho-phenylphenolato) aluminum (III), bis ( 2,4-dimethyl-8-quinolinolato) (para-phenylphenolato) aluminum (III), bis (2,4-dimethyl-8-quinolinolato) (meta-phenylphenolato) aluminum (III), bis (2, 4-dimethyl-8-quinolinolato) (3,5-dimethylphenolato) aluminum (III), bis (2,4-dimethyl-8-quinolinolato) (3,5-di-tert-butyl) Rufenolato) aluminum (III), bis (2-methyl-4-ethyl-8-quinolinolato) (para-cresolato) aluminum (III), bis (2-methyl-4-methoxy-8-quinolinolato) (para-phenylphenol) Lato) aluminum (III), bis (2-methyl-5-cyano-8-quinolinolato) (ortho-cresolato) aluminum (III), bis (2-methyl-6-trifluoromethyl-8-quinolinolato) (2- Naphthato) aluminum (III).

  In addition, bis (2-methyl-8-quinolinolato) aluminum (III) -μ-oxo-bis (2-methyl-8-quinolinolato) aluminum (III), bis (2,4-dimethyl-8-quinolinolato) aluminum (III) -μ-oxo-bis (2,4-dimethyl-8-quinolinolato) aluminum (III), bis (4-ethyl-2-methyl-8-quinolinolato) aluminum (III) -μ-oxo-bis ( 4-ethyl-2-methyl-8-quinolinolato) aluminum (III), bis (2-methyl-4-methoxyquinolinolato) aluminum (III) -μ-oxo-bis (2-methyl-4-methoxyquinolino) Lato) aluminum (III), bis (5-cyano-2-methyl-8-quinolinolato) aluminum (III) -μ-oxo-bis (5-cyano-2-methyl-8-quinolinolato) alumini Um (III), bis (2-methyl-5-trifluoromethyl-8-quinolinolato) aluminum (III) -μ-oxo-bis (2-methyl-5-trifluoromethyl-8-quinolinolato) aluminum (III) Etc.

  As other host substances, a phenylanthracene derivative described in Japanese Patent Application No. 6-110568 and a tetraarylethene derivative described in Japanese Patent Application No. 6-114456 are also preferable.

The phenylanthracene derivative is represented by the following formula (VIII).
A ₁ -L ₁ -A ₂ (VIII)
In the formula (VIII), A1 and A2 each represent a monophenylanthryl group or a diphenylanthryl group, which may be the same or different.
The monophenylanthryl group or diphenylanthryl group represented by A ₁ or A ₂ may be unsubstituted or may have a substituent. In the case of having a substituent, examples of the substituent include an alkyl group, aryl Group, alkoxy group, aryloxy group, amino group and the like, and these substituents may be further substituted. The substitution position of such a substituent is not particularly limited, but is preferably not a anthracene ring but a phenyl group bonded to the anthracene ring. Moreover, it is preferable that the bonding position of the phenyl group in the anthracene ring is the 9th or 10th position of the anthracene ring.

In the formula (VIII), L ₁ represents a single bond or an arylene group. The arylene group represented by L ₁ is preferably unsubstituted. Specifically, in addition to a normal arylene group such as a phenylene group, a biphenylene group, and an anthrylene group, two or more arylene groups are directly present. The connected thing is mentioned. L ₁ is preferably a single bond, a p-phenylene group, a 4,4′-biphenylene group, or the like.

The arylene group represented by L ₁ may be a group in which two or more arylene groups are linked via an alkylene group, —O—, —S—, or —NR—. Here, R represents an alkyl group or an aryl group. Examples of the alkyl group include a methyl group and an ethyl group, and examples of the aryl group include a phenyl group. Among them, an aryl group is preferable, and in addition to the above-described phenyl group, A ₁ and A ₂ may be used, and further, A ₁ or A ₂ may be substituted on the phenyl group. The alkylene group is preferably a methylene group or an ethylene group. Specific examples of such an arylene group are shown below.

式（IX）において、Ａｒ₁、Ａｒ₂およびＡｒ₃は、各々芳香族残基を表し、これらは同一でも異なるものであってもよい。 The tetraarylethene derivative is represented by the following formula (IX).

In the formula (IX), Ar ₁ , Ar ₂ and Ar ₃ each represent an aromatic residue, and these may be the same or different.

Examples of the aromatic residue represented by Ar _{1 to} Ar ₃ include an aromatic hydrocarbon group (aryl group) and an aromatic heterocyclic group. The aromatic hydrocarbon group may be a monocyclic or polycyclic aromatic hydrocarbon group, and includes a condensed ring and a ring assembly. The aromatic hydrocarbon group preferably has a total carbon number of 6 to 30, and may have a substituent. In the case of having a substituent, examples of the substituent include an alkyl group, an aryl group, an alkoxy group, an aryloxy group, and an amino group. Examples of the aromatic hydrocarbon group include a phenyl group, an alkylphenyl group, an alkoxyphenyl group, an arylphenyl group, an aryloxyphenyl group, an aminophenyl group, a biphenyl group, a naphthyl group, an anthryl group, a pyrenyl group, and a perylenyl group. It is done.

The aromatic heterocyclic group preferably includes O, N, and S as a hetero atom, and may be a 5-membered ring or a 6-membered ring. Specific examples include a thienyl group, a furyl group, a pyrrolyl group, and a pyridyl group.
As the aromatic group represented by Ar _{1 to} Ar ₃ , a phenyl group is particularly preferable.
n is an integer of 2 to 6, and preferably an integer of 2 to 4.

L ₂ represents an n-valent aromatic residue, particularly a 2- to 6-valent, particularly 2- to 4-valent residue derived from an aromatic hydrocarbon, an aromatic heterocycle, an aromatic ether or an aromatic amine. Preferably there is. These aromatic residues may further have a substituent, but are preferably unsubstituted.

  The light emitting layer using the compound of the formula (IX) is combined with the above host material, and is a mixed layer of at least one kind of hole injecting and transporting compound and at least one kind of electron injecting and transporting compound. It is also preferable that a dopant is contained in the mixed layer. The content of the compound in such a mixed layer is preferably 0.01 to 20 wt%, more preferably 0.1 to 15 wt%.

  In the mixed layer, a carrier hopping conduction path can be formed, so that each carrier moves in a material that is dominant in polarity, carrier injection of the opposite polarity is less likely to occur, the organic compound is less likely to be damaged, and the device life is shortened. There is an advantage of extending. Further, by adding the compound of formula (IX) to such a mixed layer, the emission wavelength characteristic of the mixed layer itself can be changed, the emission wavelength can be shifted to a long wavelength, and The strength is increased and the stability of the element is improved.

  The hole injecting and transporting compound and the electron injecting and transporting compound used for the mixed layer can be selected from a compound for the hole injecting and transporting layer and a compound for the electron injecting and transporting layer, respectively. Among them, as the electron injecting and transporting compound to be mixed, it is preferable to use a quinoline derivative, a metal complex having 8-quinolinol or its derivative as a ligand, particularly tris (8-quinolinolato) aluminum (Alq3). . Moreover, it is also preferable to use the above phenylanthracene derivatives and tetraarylamine derivatives.

  As the compound for the hole injecting and transporting layer, it is preferable to use an amine derivative having strong fluorescence, for example, a tetraphenyldiamine derivative which is the above hole transport material, a styrylamine derivative, or an amine derivative having an aromatic condensed ring. .

  The mixing ratio in this case is determined by considering the carrier mobility and carrier concentration of each, but generally the weight ratio of the compound having a hole injecting and transporting compound / the compound having an electron injecting and transporting function is 1 / 99 to 99/1, more preferably 10/90 to 90/10, particularly about 20/80 to 80/20).

  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. In general, the light emitting layer is formed to have a predetermined thickness by depositing an organic fluorescent material or coating the light emitting layer by dispersing it in a resin binder.

  In the present invention, an electron injecting and transporting layer may be provided. For the electron injecting and transporting layer, quinoline derivatives such as organometallic complexes having 8-quinolinol and its derivatives such as tris (8-quinolinolato) aluminum (Alq3) as ligands, oxadiazole derivatives, perylene derivatives, pyridine derivatives Pyrimidine derivatives, quinoxaline derivatives, diphenylquinone derivatives, nitro-substituted fluorene derivatives, and the like can be used. The electron injecting and transporting layer may also serve as the light emitting layer. In such a case, it is 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 in the light emitting layer.

  When the compound of the present invention is used for the light emitting layer, the hole injection transport layer and the electron injection transport layer include various organic compounds used in ordinary organic EL devices, such as JP-A 63-295695, JP-A Various organic compounds described in JP-A-2-191694, JP-A-3-792 and the like can be used. For example, an aromatic tertiary amine, a hydrazone derivative, a carbazole derivative, a triazole derivative, an imidazole derivative, an indole derivative, or the like can be used for the hole injecting and transporting layer, and an organic material such as aluminum quinolinol can be used for the electron injecting and transporting layer. Metal complex derivatives, oxadiazole derivatives, pyridine derivatives, pyrimidine derivatives, quinoline derivatives, quinoxaline derivatives, diphenylquinone derivatives, perylene derivatives, fluorene derivatives, and the like can be used.

  When using the compound of this invention for a light emitting layer, it is preferable to use in combination with the said luminescent substance which is hard to be quenched by interaction. Since the compound of the present invention has strong blue fluorescence, a high-luminance light-emitting element can be realized in combination with a material having little interaction.

  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 vary depending on the design and formation method of the recombination region and the light emitting region, but usually about 5 to 500 nm, In particular, the thickness is preferably 10 to 200 nm.

  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 1 nm or more, particularly 20 nm or more.
In this case, the upper limit of the thickness of the injection layer and the transport layer is usually 500 nm for the injection layer, particularly about 100 nm, and about 500 nm for the transport layer. Such a film thickness is the same when two injection transport layers are provided.

  In addition, the recombination and emission regions 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. It is possible to design the emission color, control the emission luminance and emission spectrum by the interference effect of both electrodes, and control the spatial distribution of emission.

For the electron injection electrode, it is preferable to use a material having a low work function, for example, Li, Na, K, Mg, Al, Ag, In, an alloy containing one or more of these, an oxide, or a halide. The electron injection electrode preferably has fine crystal grains, and particularly preferably in an amorphous state. The thickness of the electron injection electrode is preferably about 10 to 1000 nm.
In addition, the sealing effect is improved by depositing and sputtering Al or a fluorine-based compound at the end of electrode formation, and the wiring resistance is reduced in the case of Al.

In order to cause the EL element to emit light, at least one of the electrodes needs to be transparent or translucent. Since the material of the electron injection electrode is limited as described above, the transmittance of the emitted light is preferably 80. It is preferable to determine the material and thickness of the hole injecting electrode so as to be at least%. Specifically, for example, ITO (tin-doped indium oxide), IZO (zinc-doped indium oxide), SnO ₂ , Ni, Au, Pt, Pd, polypyrrole, or the like is preferably used for the hole injection electrode. The thickness of the hole injection electrode 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 (thickness 80-300 nm) ITO is mentioned. In practice, the ITO film thickness and optical constant may be designed so that the interference effect due to reflection at the ITO interface can satisfy high light extraction efficiency and high color purity.
Also, in a large device such as a display, the resistance of ITO increases, so Al wiring may be used.

  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. In addition, the substrate may be a color filter film, a fluorescence conversion filter film, a dielectric reflection film, or the substrate itself may be colored to control the emission color. The stacking order shown in FIG. 1 may be reversed.

  The color filter film may be a color filter used in liquid crystal displays, etc., but the characteristics of the color filter are adjusted according to the light emitted by the organic EL to optimize the extraction efficiency and color purity. do it.

In addition, if a color filter that can cut off short-wavelength external light that is absorbed by the EL element material or the fluorescence conversion layer is used, the light resistance and display contrast of the element can be improved.
Further, an optical thin film such as a dielectric multilayer film may be used instead of the color filter.

  The fluorescence conversion filter film absorbs EL emission light and emits light from the phosphor in the fluorescence conversion film, thereby converting the color of the emitted light. The composition includes a binder, a fluorescent material, It is formed from three light absorbing materials.

  Basically, a fluorescent material having a high fluorescence quantum yield may be used, and it is desirable that the fluorescent material has strong absorption in the EL emission wavelength region. In fact, laser dyes are suitable, such as rhodamine compounds, perylene compounds, cyanine compounds, phthalocyanine compounds (including subphthalo) naphthalimide compounds, condensed ring hydrocarbon compounds, condensed heterocyclic compounds, A styryl compound or a coumarin compound may be used.

  Basically, a material that does not quench the fluorescence may be selected as the binder, and a material that can be finely patterned by photolithography, printing, or the like is preferable. Further, a material that is not damaged during ITO film formation is preferable.

  The light absorbing material is used when the light absorption of the fluorescent material is insufficient, but may not be used when it is not necessary. As the light absorbing material, a material that does not quench the fluorescence of the fluorescent material may be selected.

Next, the manufacturing method of the EL element of the present invention will be described.
The electron injection electrode and the hole injection electrode are preferably formed by a vapor deposition method such as a vapor deposition method or a sputtering method.

  In forming 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 can be obtained. If the crystal grain size exceeds 0.1 μm, non-uniform light emission occurs, the drive voltage of the element must be increased, and the hole injection efficiency is significantly reduced.

The conditions for vacuum deposition are not particularly limited, but it is preferable that the degree of vacuum is 10 ⁻⁵ Torr (10 ⁻⁴ Pa) or less and the deposition rate is about 0.01 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. Further, the driving voltage of the element can be lowered, and the growth / generation of dark spots can be suppressed.

  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 individually controlling the temperature.

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

  Hereinafter, the present invention will be described in more detail by showing specific synthesis examples and examples of the present invention.

<Synthesis Example 1>
Synthesis of N, N′-diphenyl-N, N′-bis [N-phenyl-N-3-tolyl (4-aminophenyl)] benzidine (HIM33: Compound No. 3).

  In a 200 ml reaction vessel, add 26 g of N, N-diphenyl-1,4-phenylenediamine, 22 g of 3-iodotoluene, 0.3 g of activated copper powder, 50 g of potassium carbonate and 50 ml of decalin, and the temperature of the oil bath in an Ar atmosphere. Heated at 200 ° C. for 24 hours. After completion of the reaction, 100 ml of toluene was added and filtered to remove insoluble matters, and the filtrate was washed with water and dried over sodium sulfate. After drying, the solvent was distilled off from the filtrate, and the residue was purified twice on a silica gel column (developing solvent: n-hexane / toluene mixed solvent), and N, N'-diphenyl-N- (3-tolyl) -1,4 -17 g of phenylenediamine was obtained.

  Next, in a 200 ml reaction vessel, 10 g of the N, N′-diphenyl-N-3-tolyl-1,4-phenylenediamine obtained above, 4.6 g of 4,4′-diiodobiphenyl and activated copper powder 0.3 g, 8.0 g of potassium carbonate and 100 ml of decalin were added and heated in an Ar atmosphere at an oil bath temperature of 220 ° C. for 40 hours. After completion of the reaction, 200 ml of toluene was added, insoluble matters were removed by filtration, and the filtrate was washed with water and dried over sodium sulfate. After drying, the solvent was distilled off from the filtrate, and the residue was purified four times on a silica gel column (developing solvent: n-hexane / toluene mixed solvent), and N, N'-diphenyl-N, N-bis [N-phenyl-N 7 g of -3-tolyl (4-aminophenyl)] benzidine was obtained. Of these, 2 g was purified by sublimation, yielding 1.8 g of a slightly light yellowish glassy compound exhibiting strong blue fluorescence. This compound has the structure shown in HIM33 below.

Mass spectrometry: m / e 850 (M ⁺ )
^{The 1} H-NMR spectrum is shown in FIG.
^{The 13} C-NMR spectrum is shown in FIG.
The infrared absorption spectrum is shown in FIG.
Differential scanning calorimetry (DSC)
Melting point 234 ° C (partially amorphous)
Glass transition temperature (DSC) 99 ° C

<Synthesis Example 2>
Synthesis of N, N′-diphenyl-N, N′-bis [N-phenyl-N-4-tolyl (4-aminophenyl)] benzidine (HIM34: Compound No. 2).

  In the same manner as in Synthesis Example 1 except that 4-iodotoluene was used instead of 3-iodotoluene in Synthesis Example 1, N.N′-diphenyl-N, N′-bis [ N-phenyl-N-4-tolyl (4-aminophenyl)] benzidine was obtained.

Mass spectrometry: m / e 850 (M ⁺ )
^{The 1} H-NMR spectrum is shown in FIG.
^{The 13} C-NMR spectrum is shown in FIG.
An infrared absorption spectrum is shown in FIG.
Differential scanning calorimetry (DSC)
Melting point Cannot be measured due to amorphous glass transition temperature (DSC) 107 ° C

<Synthesis Example 3>
Synthesis of N, N′-diphenyl-N, N′-bis [N-phenyl-N-4-tolyl (4-aminophenyl)] benzidine (HIM38: Compound No. 16).

  In Synthesis Example 1, except that 1-iodonaphthalene was used in place of 3-iodotoluene, N, N′-diphenyl-N, N′-bis [ N-phenyl-N-4-tolyl (4-aminophenyl)] benzidine was obtained.

Mass spectrometry: m / e 922 (M ⁺ )
^{The 1} H-NMR spectrum is shown in FIG.
^{The 13} C-NMR spectrum is shown in FIG.
An infrared absorption spectrum is shown in FIG.
Differential scanning calorimetry (DSC)
Melting point Cannot be measured due to amorphous glass transition temperature (DSC) 125 ° C

<Synthesis Example 4>
Synthesis of N, N′-diphenyl-N, N′-bis [N-phenyl-N-4-tolyl (4-aminophenyl)] benzidine (HIM35: Compound No. 10).

  In Synthesis Example 1, except that 3-iodobiphenyl was used instead of 3-iodotoluene, N, N′-diphenyl-N, N′-bis [ N-phenyl-N-4-tolyl (4-aminophenyl)] benzidine was obtained.

Mass spectrometry: m / e 974 (M ⁺ )
Differential scanning calorimetry (DSC)
Melting point Cannot be measured due to amorphous glass transition temperature (DSC) 120 ° C

<Synthesis Example 5>
N, N′-diphenyl-N, N′-bis {N-phenyl-N- [N-3-tolyl-N-phenyl (4-aminophenyl)] (4-aminophenyl)} benzidine (HIM73: Compound No. .26).

  In the same manner as in Synthesis Example 1, N, N′-diphenyl-N- (3-tolyl) -1,4-phenylenediamine was obtained.

  Add 17.5 g of N, N'-diphenyl-N-3-tolylphenylenediamine, 32 g of 1,4-diiodobenzene, 0.3 g of activated copper powder, 50 g of potassium carbonate and 50 ml of decalin to a 200 ml reaction vessel, and add Ar. In the atmosphere, it was heated at an oil bath temperature of 200 ° C. for 24 hours. After completion of the reaction, 100 ml of toluene was added and filtered to remove insoluble matters, and the filtrate was washed with water and dried over sodium sulfate. After drying, the solvent was distilled off from the filtrate, and the residue was washed with acetone. The residue was purified twice with a silica gel column (developing solvent: n-hexane / toluene mixed solvent), and N, N'-diphenyl-N- 20 g of 3-tolyl-N′-4- (iodophenyl) -1,4-phenylenediamine was obtained.

  Then, 13.8 g of N, N'-diphenyl-N- (3-tolyl) -N '-(4-iodophenyl) -1,4-phenylenediamine and N, N'-diphenylbenzidine 4 were added to a 200 ml reaction vessel. .28 g, 0.3 g of activated copper powder, 26 g of potassium carbonate and 50 ml of decalin were added and heated in an Ar atmosphere at an oil bath temperature of 200 ° C. for 24 hours. After completion of the reaction, 100 ml of toluene was added and filtered to remove insoluble matters, and the filtrate was washed with water and dried over sodium sulfate. After drying, the solvent was distilled off from the filtrate, and the residue was purified twice on a silica gel column (developing solvent: n-hexane / toluene mixed solvent), and N, N'-diphenyl-N, N'-bis {N-phenyl- 8 g of N- [N-3-tolyl-N-phenyl (4-aminophenyl)] (4-aminophenyl)} benzidine was obtained. Of these, 2 g was purified by sublimation, yielding 1.8 g of a slightly light yellowish glassy compound exhibiting strong blue fluorescence. This compound has a structure represented by the following HIM73.

Mass spectrometry: m / e 1184 (M ⁺ )
^{The 1} H-NMR spectrum is shown in FIG.
^{The 13} C-NMR spectrum is shown in FIG.
An infrared absorption spectrum is shown in FIG.
Differential scanning calorimetry (DSC)
Melting point Cannot be measured due to amorphous glass transition temperature (DSC) 122 ° C

<Synthesis Example 6>
N, N′-diphenyl-N, N′-bis {N-phenyl-N- [N-phenyl-N-4-tolyl (4-aminophenyl)] (4-aminophenyl)} benzidine (HIM74: Compound No. .25).

  In Synthesis Example 5, N, N′-diphenyl-N, N′-bis having the structure represented by the following HIM74 was obtained in the same manner as Synthesis Example 1 except that 4-iodotoluene was used instead of 3-iodotoluene. [N-phenyl-N- (N-phenyl-N-4-tolyl (4-aminophenyl)] (4-aminophenyl) benzidine was obtained.

Mass spectrometry: m / e 1184 (M ⁺ )
^{The 1} H-NMR spectrum is shown in FIG.
^{The 13} C-NMR spectrum is shown in FIG.
An infrared absorption spectrum is shown in FIG.
Differential scanning calorimetry (DSC)
Melting point Not possible due to amorphous glass transition temperature (DSC) 126 ° C

<Synthesis Example 7>
N, N′-diphenyl-N, N′-bis {N-phenyl-N- [N-phenyl-N-1-naphthyl (4-aminophenyl)] (4-aminophenyl)} benzidine (HIM78: Compound No. .40).

  In Synthesis Example 5, except that 1-iodonaphthalene was used in place of 3-iodotoluene, N, N′-diphenyl-N, N-bis { N-phenyl-N- [N-phenyl-N-1-naphthyl (4-aminophenyl)] (4-aminophenyl)} benzidine was obtained.

Mass spectrometry: m / e 1256 (M ⁺ )
^{The 1} H-NMR spectrum is shown in FIG.
^{The 13} C-NMR spectrum is shown in FIG.
The infrared absorption spectrum is shown in FIG.
Differential scanning calorimetry (DSC)
Melting point Cannot be measured due to amorphous glass transition temperature (DSC) 138 ° C

<Synthesis Example 8>
N, N ″ -diphenyl-N, N ″ -bis [N-phenyl-N-3-tolyl (4-aminophenyl)]-1.1 ″ -terphenyl-4,4 ″ -diamine (HTL103: Synthesis of compound No. 359).

  To a 1000 ml reaction vessel, 26 g of 4,4 ″ -diamino-p-terphenyl, 200 ml of pure water, and 100 ml of concentrated hydrochloric acid were added, stirred in a suspended state, and the vessel was immersed in an ice bath. After cooling to 5 ° C. or lower, an aqueous solution in which 15 g of sodium nitrite was dissolved in 200 ml of pure water was slowly dropped, and the mixture was returned to room temperature and stirred for 2 hours. The organic layer was extracted from the reaction solution with ethyl acetate, washed and dried. The resulting brown liquid was purified three times on a silica gel column to obtain 30 g of 4,4 ″ -diiodo-p-terphenyl.

  In a 200 ml reaction vessel, 21 g of N, N′-diphenyl-N-3-tolylphenylenediamine, 10 g of 4,4 ″ -diiodo-p-terphenyl, 0.3 g of active copper powder, 50 g of potassium carbonate and decalin 50 ml was added and heated in an Ar atmosphere at an oil bath temperature of 200 ° C. for 24 hours. After completion of the reaction, 100 ml of toluene was added and filtered to remove insoluble matters, and the filtrate was washed with water and dried over sodium sulfate. After drying, the solvent was distilled off from the filtrate, and the residue was purified twice with a silica gel column (developing solvent: n-hexane / toluene mixed solvent), and N, N ″ -diphenyl-N, N having the structure shown by the following HTL103 15 g of ″ -bis [N-phenyl-N-3-tolyl (4-aminophenyl)]-1,1 ″ -terphenyl-4,4 ″ -diamine was obtained.

質量分析：ｍ／ｅ ９２６（Ｍ⁺）

Mass spectrometry: m / e 926 (M ⁺ )

<Synthesis Example 9>
Synthesis of N, N ″ -diphenyl-N, N ″ -bis (N, N-diphenylaminophenyl) benzidine (HIM30: Compound No. 1) Part 2

In Synthesis Example 1, iodobenzene was used instead of 3-iodotoluene.
Mass spectrometry: m / e 822 (M ⁺ )
Differential scanning calorimetry Melting point 246 ° C
Glass transition temperature (DSC) 107 ° C
Crystallization temperature 212 ° C
Compared with the compounds of Synthesis Examples 1 to 8, the crystallinity is somewhat higher, but the film physical properties during vapor deposition were in an amorphous state.

<Example 1>
A glass substrate having an ITO transparent electrode (hole injection electrode) with a thickness of 100 nm is ultrasonically cleaned with a neutral detergent, acetone, and ethanol, pulled up from boiling ethanol and dried, and after UV ozone cleaning, It fixed to the board | substrate holder and pressure-reduced to 1 * 10 < ^-6 > Torr (10 <^-4> Pa).

  Next, the above N, N′-diphenyl-N, N′-bis [N-phenyl-N-3-tolyl (4-aminophenyl)] benzidine (HIM33: Compound No. 3) was deposited at a deposition rate of 0.2 nm / Vapor deposition was performed in sec to a thickness of 50 nm to form a hole injection layer.

  N, N, N ′, N′-tetrakisbis-(-3-biphenyl-1-yl) benzidine (TPD) having the structure shown below and rubrene are in a weight ratio of 10: 1 and a deposition rate of 0.2 nm / The film was co-evaporated to a thickness of 20 nm at sec to obtain a hole transporting light emitting layer.

  Next, while maintaining the reduced pressure state, tris (8-quinolinolato) aluminum (Alq3) was deposited to a thickness of 50 nm at a deposition rate of 0.2 nm / sec as an electron injecting and transporting layer.

Further, while maintaining the reduced pressure state, the vapor deposition rate of MgAg (weight ratio 10: 1)
The film was deposited at a thickness of 200 nm at 2 nm / sec to form an electron injection electrode, and Al was deposited to a thickness of 100 nm as a protective layer to obtain an organic EL device.

When a voltage was applied to this organic EL element and a current was passed, it was 25,200 cd / m ² yellow at 12 V, 850 mA / cm ² (light emission maximum wavelength λ max = 565 nm, chromaticity coordinate x = 0.47 y = 0. 51) was confirmed, and this light emission was stable for 10,000 hours or more in a dry argon atmosphere. There was no emergence or growth of partially non-light emitting parts. The half life of the luminance was 500 hr (initial luminance 2,030 cd / m ² initial driving voltage 6.55 V, driving voltage increase 3.5 V) by constant current driving at 30 mA / cm ² .

  Furthermore, when the device prepared in the same manner was left in a high-temperature bath at 85 ° C. and 100 ° C., no unevenness occurred on the light emitting surface even after 500 hours. Further, there was no generation / growth of dark spots of 0.1 mm or more.

<Example 2>
A device was produced in the same manner as in Example 1. However, instead of the above HIM33 (compound No. 3), N, N′-diphenyl-N, N′-bis [N-phenyl-N-4-tolyl (4-aminophenyl)] benzidine (HIM34: compound no. .2) was used.

When a voltage was applied to the EL element and a current was passed, it was yellow of 26,000 cd / m ² at 12 V, 720 mA / cm ² (maximum emission wavelength λmax = 565 nm, chromaticity coordinate x = 0.47y = 0.51). ) Was confirmed, and this luminescence was stable for 10,000 hours or more in a dry nitrogen atmosphere. There was no emergence or growth of partially non-light emitting parts. The half life of the luminance was 800 hr (2,040 cd / m 2 initial drive voltage 6.59 V, drive voltage increase 3.0 V) with constant current drive of 30 mA / cm 2.

  Furthermore, when the device prepared in the same manner was left in a high-temperature bath at 85 ° C. and 100 ° C., no unevenness occurred on the light emitting surface even after 500 hours. Further, there was no generation / growth of dark spots of 0.1 mm or more.

<Example 3>
A device was produced in the same manner as in Example 1. However, instead of the above HIM33 (Compound No. 3), N, N′-diphenyl-N, N′-bis [N-phenyl-N-4-tolyl (4-aminophenyl)] benzidine (HIM38: Compound No. 3) .16) was used.

When a voltage was applied to this EL element and a current was passed, it was yellow of 26,000 cd / m ² at 12 V, 825 mA / cm ² (maximum light emission wavelength λmax = 565 nm, chromaticity coordinate x = 0.48 y = 0.50). ) Was confirmed, and this luminescence was stable for over 10,000 hours in a dry nitrogen atmosphere. There was no emergence or growth of partially non-light emitting parts. The half life of the luminance was 1,600 hr (1,923 cd / m ² initial driving voltage 6.59 V, driving voltage increase 1.5 V) with constant current driving at 30 mA / cm ² .

Furthermore, when the device prepared in the same manner was left in a high-temperature bath at 85 ° C. and 100 ° C., no unevenness occurred on the light emitting surface even after 500 hours. Further, there was no generation / growth of dark spots of 0.1 mm or more.

<Example 4>
A device was produced in the same manner as in Example 1. However, instead of the above HIM33 (compound No. 3), N, N′-diphenyl-N, N′-bis {N-phenyl-N- [N-3-tolyl-N-phenyl (4-aminophenyl)] ] (4-aminophenyl)} benzidine (HIM73: Compound No. 26) was used.

When a voltage was applied to the EL element and a current was passed, it was yellow at 24,800 cd / m ² at 13 V · 1, 155 mA / cm ² (emission maximum wavelength λmax = 565 nm, chromaticity coordinate x = 0.49y = 0). .50) was confirmed, and this light emission was stable for 10,000 hours or more in a dry nitrogen atmosphere. There was no emergence or growth of partially non-light emitting parts. The half life of the luminance was 1,000 hr (1,841 cd / m2 initial drive voltage 6.76 V, drive voltage increase 2.5 V) with constant current drive of 30 mA / cm 2.
Furthermore, when the device prepared in the same manner was left in a high-temperature bath at 85 ° C. and 120 ° C., no unevenness occurred on the light emitting surface even after 500 hours. Further, there was no generation / growth of dark spots of 0.1 mm or more.

<Example 5>
A device was produced in the same manner as in Example 1. However, instead of the above HIM33 (compound No. 3), N, N′-diphenyl-N, N′-bis {N-phenyl-N- [N-phenyl-N-4-tolyl (4-aminophenyl)] ] (4-aminophenyl)} benzidine (HIM74: Compound No. 25) was used.

When a voltage was applied to this EL element and a current was passed, it was yellow (light emission maximum wavelength λmax = 564 nm, chromaticity coordinate x = 0.49y = 0.50) at 13V · 1155 mA / cm ² and 24800 cd / m ² . Luminescence was confirmed, and this luminescence was stable for over 10,000 hours in a dry nitrogen atmosphere. There was no emergence or growth of partially non-light emitting parts. The half life of the luminance was 1,000 hr (1,841 cd / m ² initial drive voltage 6.76 V, drive voltage increase 1.5 V) with constant current drive of 30 mA / cm ² .

  Furthermore, when the device prepared in the same manner was left in a high-temperature bath at 85 ° C. and 120 ° C., no unevenness occurred on the light emitting surface even after 500 hours. Further, there was no generation / growth of dark spots of 0.1 mm or more.

<Example 6>
Instead of HIM33 (Compound No. 3) in Example 1, N, N′-diphenyl-N, N′-bis [N-phenyl-N-4-tolyl (4-aminophenyl)] benzidine (HIM35: Compound) No. 10) or N, N′-diphenyl-N, N′-bis {N-phenyl-N- [N-phenyl-N-1-naphthyl (4-aminophenyl)] (4-aminophenyl)} benzidine When (HIM78: Compound No. 40) was used, the same result as in Example 1 was obtained. Similar results were obtained with other exemplary compounds.

<Example 7>
A device was produced in the same manner as in Example 1. However, the hole transporting light emitting layer of Example 1 was mixed with TPD as a hole transporting material, rubrene as a light emitting material with the following structure, and aluminum quinolinol (Alq3) as an electron injecting material with the following structure in a weight ratio of 5: 5 1, a mixed layer having a thickness of 40 nm was formed by three-source co-evaporation to form a mixed light emitting layer, and then aluminum quinolinol (Alq3) was evaporated to 30 nm as an electron injecting and transporting layer.

When a voltage was applied to the EL element and a current was passed, it was 26,300 cd / m ² yellow at 13 V, 980 mA / cm ² (light emission maximum wavelength λmax = 565 nm, chromaticity coordinate x = 0.49y = 0.51). ) Was confirmed, and this luminescence was stable for 10,000 hours or more in a dry nitrogen atmosphere. There was no emergence or growth of partially non-light emitting parts. The half life of the luminance was 30,000 hr (2,350 cd / m ² driving voltage increase 1.0 V) with a constant current driving of 30 mA / cm ² and 10,000 hr or more at an initial luminance of 300 cd / m ² .

  Furthermore, when the device prepared in the same manner was left in a high-temperature bath at 85 ° C., no unevenness occurred on the light emitting surface even after 500 hours. Further, there was no generation / growth of dark spots of 0.1 mm or more.

<Example 8>
The hole transporting light emitting layer of Example 1 is a TPD-only hole transport layer, the Alq3 electron injection transport layer is 10 nm, and a tetraphenylethene having a thickness of 30 nm is provided between the hole transport layer and the electron injection transport layer. Alternatively, when a light emitting layer of phenylanthracene was provided, the same result as above was obtained.

<Comparative Example 1>
A device was produced in the same manner as in Example 1. However, instead of HIM33 (Compound No. 3), 4,4 ′, 4 ″ -tris [—N-(-3-methylphenyl) -N-phenylamino] triphenylamine (MTDATA) having the following structure Was used.

When a voltage was applied to the EL element and a current was applied, it was yellow of 21,400 cd / m ² at 14 V · 767 mA / cm ² (maximum emission wavelength λmax = 565 nm, chromaticity coordinate x = 0.48y = 0.50). ) Was confirmed, and this luminescence was stable for 10,000 hours or more in a dry nitrogen atmosphere. The half life of the luminance was 400 hr (2,120 cd / m ² initial drive voltage 7.9 V, drive voltage rise 4.5 V) with constant current drive of 30 mA / cm ² .

  Furthermore, when the device produced in the same manner was left in a high-temperature bath at 85 ° C., unevenness occurred on the light emitting surface in 10 hours. In addition, the generation and growth of dark spots was remarkable.

<Comparative example 2>
A device was produced in the same manner as in Example 1. However, instead of HIM33 (Compound No. 3), copper phthalocyanine having the following structure was used at a thickness of 10 nm.

When a voltage was applied to this EL element and a current was passed, it was yellow of 21,000 cd / m ² at 14 V, 532 mA / cm ² (maximum emission wavelength λmax = 565 nm, chromaticity coordinate x = 0.49y = 0.50). ), And the luminance half-life was confirmed to be 200 hr (1,873 cd / m ² initial driving voltage 6.50 V driving voltage rise 8.0 V) with a constant current driving of 30 mA / cm ² , but a dark spot As a result, the brightness could not be measured accurately.

  Furthermore, when the device prepared in the same manner was left in a high-temperature bath at 85 ° C., unevenness was generated on the light emitting surface between 10:00 and 00:00. In addition, the generation and growth of dark spots was remarkable.

<Example 9>
A glass substrate having an ITO transparent electrode (hole injection electrode) with a thickness of 100 nm is ultrasonically cleaned with a neutral detergent, acetone, and ethanol, pulled up from boiling ethanol and dried, and after UV ozone cleaning, It fixed to the board | substrate holder and pressure-reduced to 1 * 10 < ^-6 > Torr (10 <^-4> Pa).

Next, the above N, N′-diphenyl-N, N′-bis [N-phenyl-N-4-tolyl (4-aminophenyl)] benzidine (HIM34: Compound No. 2) was deposited at a deposition rate of 0.2 nm / Evaporated to a thickness of 200 nm in sec.
Further, while maintaining the reduced pressure state, Al was vapor-deposited at a deposition rate of 2 nm / sec to a thickness of 200 nm to form an electron injection electrode, thereby obtaining a single-layer device.

When a voltage was applied to this element to pass a current, a current of 100 mA / cm ² was flowed at 5V. When this element was driven at a constant current of 100 mA / cm ² , a current was flowed stably for 1000 hours, and the voltage rise during that period was 0.5 V. Furthermore, the voltage versus current density characteristics of this device were measured. The results are shown in FIG.

Further, after the N, N′-diphenyl-N, N′-bis [N-phenyl-N-4-tolyl (4-aminophenyl)] benzidine (HIM34: Compound No. 2) was laminated, the time of flight The hole mobility was measured by the method and found to be 2.7 × 10 ⁻³ cm ² / Vs. This value is compared with TPD [N, N'-bis (3-methylphenyl) -N, N'-diphenyl-1,1-biphenyl-4.4'-diamine], which is a general hole injecting and transporting substance. The mobility is twice or more times faster.

<Comparative Example 3>
In Example 9, a device was obtained in the same manner as in Example 9 except that the above MTDATA was used instead of HIM34.

When a current was applied by applying a voltage to this device, only a current of 20 mA / cm ² flowed at 5 v. When this element was driven at a constant current of 100 mA / cm ² , a current was flowed stably for 1000 hours, and the voltage rise during that period was 3.1 V. Furthermore, the voltage versus current density characteristics of this device were measured. The results are shown in FIG.

  As is apparent from FIG. 20, since the element of the present invention has a high hole supply efficiency, it can be seen that a larger current density can be obtained at the same voltage.

<Example 10>
In Example 2, hole injection layer containing N, N′-diphenyl-N, N′-bis [N-phenyl-N-4-tolyl (4-aminophenyl)] benzidine (HIM34: Compound No. 2) An organic EL device was produced in the same manner as in Example 2 except that the film thickness was changed from 50 nm to 300 nm.

When a voltage was applied to this EL element and a current was applied, it was yellow at 24,500 cd / m ² at 13 V, 800 mA / cm ² (maximum emission wavelength λmax = 565 nm, chromaticity coordinate x = 0.47y = 0.51). ) Was confirmed, and this luminescence was stable for 10,000 hours or more in a dry argon atmosphere. There was no emergence or growth of partially non-light emitting parts. The half life of the luminance was 1500 hr (initial luminance 1800 cd / m ² , initial driving voltage 7.6 V, driving voltage increase 3.0 V) with constant current driving at 30 mA / cm ² .

  Furthermore, when the device produced in the same manner was left in a constant temperature bath at 85 ° C., no uneven light emission could be confirmed on the light emitting surface even after 500 hours. Moreover, generation | occurrence | production and growth of the dark spot of 0.1 mm or more were not confirmed.

  From the above results, it can be seen that the drive voltage hardly increases even when the layer containing the compound of the present invention is thickened.

As described above, the organic EL device using the compound of the present invention suppresses the increase in driving voltage and the decrease in luminance at the time of driving the device, the leakage of current, the appearance and growth of a partial non-light emitting portion, and the decrease in the luminance is small. High luminance, high reliability such as high heat resistance, and the like can provide an optimum work function for a hole injection electrode and an organic material to be combined, and an element with high continuous light emission reliability can be obtained.
In addition, an organic EL element having high hole mobility and capable of obtaining a larger current density can be obtained.

It is the schematic block diagram which showed the structural example of the organic EL element of this invention. 1 is a ¹ H-NMR spectrum diagram of Synthesis Example 1. FIG. 3 is a ¹³ C-NMR spectrum diagram of Synthesis Example 1. FIG. 2 is an infrared absorption spectrum diagram of Synthesis Example 1. FIG. 2 is a ¹ H-NMR spectrum diagram of Synthesis Example 2. FIG. 6 is a ¹³ C-NMR spectrum diagram of Synthesis Example 2. FIG. 6 is an infrared absorption spectrum diagram of Synthesis Example 2. FIG. 2 is a ¹ H-NMR spectrum diagram of Synthesis Example 3. FIG. 6 is a ¹³ C-NMR spectrum diagram of Synthesis Example 3. FIG. It is an infrared absorption spectrum figure of the synthesis example 3. 6 is a ¹ H-NMR spectrum diagram of Synthesis Example 5. FIG. 6 is a ¹³ C-NMR spectrum diagram of Synthesis Example 5. FIG. 6 is an infrared absorption spectrum diagram of Synthesis Example 5. FIG. 6 is a ¹ H-NMR spectrum diagram of Synthesis Example 6. FIG. 6 is a ¹³ C-NMR spectrum diagram of Synthesis Example 6. FIG. 6 is an infrared absorption spectrum diagram of Synthesis Example 6. FIG. 6 is a ¹ H-NMR spectrum diagram of Synthesis Example 7. FIG. ^{14 is} a ¹³ C-NMR spectrum diagram of Synthesis Example 7. FIG. 14 is an infrared absorption spectrum diagram of synthesis example 7. FIG. It is a graph which shows the voltage versus current density characteristic of HIM34 which is the hole injection transport material of this invention, and the conventional MTDATA.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Organic EL element 2 Substrate 3 Anode 4 Hole injection transport layer 5 Light emitting layer 6 Electron injection transport layer 7 Cathode

Claims (9)

An organic EL device comprising a compound having an organic compound layer and at least one organic compound layer having a skeleton represented by the following formula (I).

(In the above formula (I), L ₀ is any of 2 to 4 ring o-, p-, or m-phenylene groups, and when the number of phenylene groups is 4 rings, unsubstituted Alternatively, it may have an aminophenyl group having a substituent, and these phenylene groups may have a substituent, and R ₀₁ , R ₀₂ , R ₀₃ , and R ₀₄ are respectively

Represents one of the following. Here, R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ , R ₁₅ , R ₁₆ and R ₁₇ each represent a substituted or unsubstituted aryl group. r ₁ , r ₂ , r ₃ and r ₄ are each an integer of 0 to 5 members, but r ₁ + r ₂ + r ₃ + r ₄ is 1 or more. However, r ₁ ~r ₄ is 0 or _{1, r 1 + r 2 +} r 3 + r 4 is 1 or 2, the R ₀₁ to R ₀₄

In this case, R ₁₁ and R ₁₂ represent a substituted or unsubstituted aryl group excluding the tolyl group. ) 2. The organic EL device according to claim 1, wherein the phenylene group represented by L ₀ is a 4,4′-biphenylene group.   An organic EL device comprising at least two organic compound layers, wherein the organic compound layer according to claim 1 or 2 is an organic compound layer having a hole injecting and transporting function.   3. The organic compound layer according to claim 1 or 2, comprising at least three organic compound layers including an organic compound layer having a hole injection function and an organic compound layer having a hole transport function. An organic EL element which is an organic compound layer having the hole injection function.   The organic EL device according to claim 3 or 4, wherein the organic compound layer has a light emitting layer in at least one layer, and the light emitting layer contains a hole transporting compound and an electron transporting compound.   The light emitting layer exists between an organic compound layer having a hole injection function and / or an organic compound layer having a hole transport function and an organic compound layer having an electron transport function and / or an organic compound layer having an electron injection function The organic EL element according to claim 5.   An organic EL device comprising, on the hole injection electrode, at least an organic compound layer having a hole injection / transport function according to claim 3, an organic compound layer having a hole transport function, a light emitting layer, and an electron injection electrode in order. .   An organic EL device having, on the hole injection electrode, at least an organic compound layer having a hole injection function according to claim 4, a light emitting layer, and an electron injection electrode.   The organic EL element according to any one of claims 3 to 8, wherein a film thickness of the organic compound layer having the hole injection function is 100 nm or more.

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