JP2013062201A - Method for manufacturing organic electroluminescent element, and organic electroluminescent element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably manufacture an organic electroluminescent element having high luminous efficiency and long life, by a wet process under an environment at an oxygen concentration/moisture concentration realizable in volume production.SOLUTION: In an organic electroluminescent element, a luminous layer containing at least a phosphorescent luminescent material is held between an anode and a cathode, and the luminous layer is formed by a wet process. A method for manufacturing the organic electroluminescent element includes the steps of: preparing a coating liquid including a phosphorescent luminescent material which is dispersed in a light emitting host material contained in the luminous layer, has a phosphorescence lifetime of less than 1.4 μs at room temperature in a film state, and has a phosphorescence quantum yield of 70% or more; and coating the coating liquid under an inert gas atmosphere at an oxygen concentration of 10-2,000 ppm and a moisture concentration of 10-2,000 ppm to be dried.

Description

  The present invention relates to a method for manufacturing an organic electroluminescence element. Specifically, the present invention relates to a method for manufacturing an organic electroluminescent element and an organic electroluminescent element that can be manufactured by a simple process and have improved luminous efficiency and lifetime.

  As a light-emitting electronic display device, there is an electroluminescence display (hereinafter abbreviated as ELD). Examples of the ELD include an inorganic electroluminescence element (hereinafter also referred to as an inorganic EL element) and an organic electroluminescence element (hereinafter also referred to as an organic EL element). Inorganic EL elements have been used as planar light sources, but an alternating high voltage is required to drive the light emitting elements.

  On the other hand, an organic electroluminescence element has a configuration in which a light emitting layer containing a light emitting compound is sandwiched between a cathode and an anode. Organic electroluminescence devices use excitons (excitons) by recombination of electrons and holes injected into the light-emitting layer, and use light emission (fluorescence / phosphorescence) when the excitons are deactivated. Element emitting light. In addition, the organic electroluminescence element can emit light at a voltage of several volts to several tens of volts, and is a self-luminous type, so that it has a wide viewing angle, high visibility, and is a thin film type solid state element. Therefore, it attracts attention from the viewpoints of space saving and portability.

  Another major feature of the organic electroluminescence element is that it is a surface light source, unlike main light sources that have been put to practical use, such as light-emitting diodes and cold-cathode tubes. Applications that can effectively utilize this characteristic include illumination light sources and various display backlights. In particular, it is also suitable to be used as a backlight of a liquid crystal full color display whose demand has been increasing in recent years.

  Improvement of luminous efficiency is mentioned as a subject for putting an organic electroluminescent element into practical use as such a light source for illumination, or a backlight of a display. In order to improve the light emission efficiency, it is becoming common to incorporate a so-called host / guest structure in which a part of the organic functional layer constituting the organic electroluminescence element is formed by mixing a plurality of materials having different functions. is there. For example, a combination of a host material / a light emitting dopant in the light emitting layer, a combination of an electron transport material / an alkali metal material in the electron transport layer, and the like can be given.

On the other hand, as a method for producing these organic electroluminescence elements, there are a vapor deposition method, a wet process (spin coating method, cast method, ink jet method, spray method, printing method), etc., but continuous production is easy without requiring a vacuum process. In recent years, a manufacturing method using a wet process has attracted attention.
These wet process manufacturing methods are advantageous in terms of cost compared to vapor deposition methods in which the entire process is evacuated, but conversely are affected by moisture, oxygen, etc. contained in the atmosphere or in an inert gas atmosphere. There is a case. When affected by moisture or oxygen, there is a problem that a sufficient light emission lifetime cannot be obtained in the manufactured organic electroluminescence device.

  In order to solve such problems, it is disclosed that an organic EL element having an organic thin film layer having an oxygen concentration of 2000 ppm or less is manufactured by a wet method in an inert gas atmosphere having an oxygen concentration of 10 ppm or less and a water concentration of 10 ppm or less. (For example, refer to Patent Document 1). Also disclosed is a method for maintaining a low moisture concentration in the film by laminating a desiccant-containing film on the organic layer after film formation in an oxygen / water concentration environment where process control is possible. (For example, refer to Patent Document 2).

JP 2006-185864 A JP 2009-123532 A

  However, the technique described in Patent Document 1 performs film formation in a glove box substituted with nitrogen gas, and in industrial production, maintenance of gas confidentiality, gas adsorption separation device for dehydration, Since the cost becomes very high from various points such as the quality of the inert gas supplied, it is practically difficult. Moreover, in the technique of the said patent document 2, it is necessary to pass through the pasting process of a desiccant containing film in the stage of the intermediate product after film-forming, and a simpler process is calculated | required.

  An object of the present invention is to provide an organic electroluminescent element manufacturing method capable of stably manufacturing an organic electroluminescent element having high luminous efficiency and long life in a wet process under an oxygen concentration / moisture concentration environment capable of mass production. And it is providing an organic electroluminescent element.

The above object of the present invention can be achieved by the following constitution.
In the method of manufacturing an organic electroluminescence element, a light emitting layer containing at least a phosphorescent material is sandwiched between an anode and a cathode, and the light emitting layer is formed by a wet process.
A phosphorescent material dispersed in the light-emitting host material contained in the light-emitting layer and having a phosphorescence lifetime at room temperature in a film state of less than 1.4 μsec and a phosphorescence quantum yield of 70% or more is included. Adjusting the coating solution;
Applying and drying the coating solution in an inert gas atmosphere having an oxygen concentration of 10 to 2000 ppm and a moisture concentration of 10 to 2000 ppm.

  According to the present invention, it is possible to stably manufacture an organic electroluminescence device having high light emission efficiency and a long lifetime by a wet process in an oxygen concentration / water concentration environment that is feasible for mass production.

  Hereinafter, the best mode for carrying out the present invention will be described in detail, but the present invention is not limited thereto.

<< Layer structure of organic EL element >>
The constituent layers of the organic electroluminescence element (organic EL element) of the present invention will be described. Although the preferable specific example of the layer structure of the organic EL element of this invention is shown below, this invention is not limited to these.

(I) Anode / light emitting layer unit / electron transport layer / cathode (ii) Anode / hole transport layer / light emitting layer unit / electron transport layer / cathode (iii) Anode / hole transport layer / light emitting layer unit / hole blocking Layer / electron transport layer / cathode (iv) anode / hole transport layer / light emitting layer unit / hole blocking layer / electron transport layer / cathode buffer layer / cathode (v) anode / anode buffer layer / hole transport layer / light emission Layer unit / hole blocking layer / electron transport layer / cathode buffer layer / cathode

  Each layer which comprises the organic EL element of this invention is demonstrated one by one.

<Light emitting layer>
The light emitting layer according to the present invention is a layer that emits light by recombination of electrons and holes injected from the electrode, the electron transport layer, or the hole transport layer, and the light emitting portion is in the layer of the light emitting layer. May be the interface between the light emitting layer and the adjacent layer.

The light emitting layer according to the present invention is not particularly limited in its configuration as long as the light emitting material contained satisfies the following requirements.
Moreover, there may be a plurality of layers having the same emission spectrum and emission maximum wavelength.
It is preferable to have a non-light emitting intermediate layer between each light emitting layer.

  In the present invention, the total thickness of the light emitting layers is preferably in the range of 1 to 100 nm, and more preferably 30 nm or less. This is because a lower driving voltage can be obtained if the total film thickness is 30 nm or less. In addition, the sum total of the film thickness of the light emitting layer as used in the field of this invention is a film thickness also including the said intermediate | middle layer, when a nonluminous intermediate | middle layer exists between light emitting layers.

  The film thickness of each light emitting layer is preferably adjusted to a range of 1 to 50 nm, and more preferably adjusted to a range of 1 to 20 nm. There is no particular limitation on the relationship between the film thicknesses of the blue, green and red light emitting layers.

  For the production of the light emitting layer, a phosphorescent light emitting material or a host compound, which will be described later, can be formed by forming a film by a known wet process such as a spin coating method, a casting method, or an ink jet method.

  In the present invention, each light emitting layer may contain a plurality of light emitting materials, and a phosphorescent light emitting material and a fluorescent light emitting material may be mixed and used in the same light emitting layer.

  In the present invention, the structure of the light-emitting layer preferably contains a host compound and a light-emitting material (also referred to as a light-emitting dopant compound) and emits light from the light-emitting material.

(1) Host compound (light emitting host material)
The host compound contained in the light emitting layer of the organic EL device according to the present invention is defined as a compound having a phosphorescence quantum yield of phosphorescence emission at room temperature (25 ° C.) of less than 0.1. The phosphorescence quantum yield is preferably less than 0.01. Moreover, it is preferable that the volume ratio in the layer is 50% or more among the compounds contained in a light emitting layer.

  As a host compound, a well-known host compound may be used independently, and multiple types may be used together. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the organic EL element can be made highly efficient. Moreover, it becomes possible to mix different light emission by using multiple types of luminescent material mentioned later, and can thereby obtain arbitrary luminescent colors.

  The host compound used in the present invention may be a conventionally known low molecular compound or a high molecular compound having a repeating unit, or a low molecular compound having a polymerizable group such as a vinyl group or an epoxy group (evaporation polymerization light emission). Host).

  As the known host compound, a compound having a hole transporting ability and an electron transporting ability, preventing an increase in emission wavelength, and having a high Tg (glass transition temperature) is preferable. Here, the glass transition point (Tg) is a value obtained by a method based on JIS-K-7121 using DSC (Differential Scanning Colorimetry).

  Specific examples of known host compounds include compounds described in the following documents. For example, Japanese Patent Application Laid-Open Nos. 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860 Gazette, 2002-334787 gazette, 2002-15871 gazette, 2002-334788 gazette, 2002-43056 gazette, 2002-334789 gazette, 2002-75645 gazette, 2002-338579 gazette. No. 2002-105445, No. 2002-343568, No. 2002-141173, No. 2002-352957, No. 2002-203683, No. 2002-363227, No. 2002-231453. No. 2003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-286061, No. 2002-280183, No. 2002-299060. 2002-302516, 2002-305083, 2002-305084, 2002-308837, and the like.

(2) Luminescent dopant (luminescent material)
Next, the light emitting dopant (light emitting material) will be described.
Examples of the luminescent dopant include a fluorescent dopant (fluorescent luminescent material) and a phosphorescent dopant (phosphorescent luminescent material). In the present invention, a phosphor dopant (phosphorescent luminescent material) described below is used.

  As a result of intensive studies, the present inventors have developed a phosphorescent light-emitting material exhibiting the shortest wavelength among the phosphorescent light-emitting materials contained in the light-emitting layer, in the host material contained in the light-emitting layer. It has been found that the object of the present invention described above can be achieved by using a phosphorescent material having a dispersed phosphorescent lifetime at room temperature in a film state of less than 1.4 μsec. Specifically, by using the phosphorescent material, a wet process is performed in an oxygen / moisture concentration environment capable of mass production, that is, in an inert gas atmosphere having an oxygen concentration of 10 to 2000 ppm and an oxygen concentration of 10 to 2000 ppm. Thus, it was found that an organic EL device having high luminous efficiency and long life can be produced. Furthermore, it was found that an organic EL device having high resistance to oxygen and moisture can be produced by using the phosphorescent material represented by the general formula (1) as such a phosphorescent material. This is not only due to the fact that the phosphorescence lifetime is shortened, making it less susceptible to quenching by impurities, but also due to structural factors such as the introduction of specific substituents on the outer periphery of the molecule, It is presumed that it forms a moderately associated state and is less affected by impurities, but details are unknown.

Therefore, in the method for producing an organic EL device according to the present invention, the phosphorescence lifetime at room temperature in a film state dispersed in the light emitting host material is less than 1.4 μsec, and the phosphorescence quantum yield is 70% or more. After performing the process (adjustment process) which adjusts the coating liquid for light emitting layers containing the said phosphorescent light emitting material using the phosphorescent light emitting material of this, the adjusted coating liquid for light emitting layers is oxygen concentration 10-2000 ppm, A step (application step) of applying and drying on a substrate or the like in an inert gas atmosphere having a moisture concentration of 10 to 2000 ppm is performed. The phosphorescence lifetime of the phosphorescent material used in the present invention may be less than 1.4 μsec, but is preferably 1.12 μsec or less, more preferably 1.07 μsec or less.
Hereinafter, the compounds used in the present invention will be described.

(2.1) Phosphorescent dopant (phosphorescent material)
The phosphorescent dopant compound according to the present invention is a compound in which light emission from an excited triplet is observed, specifically, a compound that emits phosphorescence at room temperature (25 ° C.), and has a phosphorescence quantum yield of 25. Although it is defined as a compound of 0.01 or more at ° C., a preferable phosphorescence quantum yield is 0.1 or more.

  The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence dopant according to the present invention achieves the phosphorescence quantum yield (0.01 or more) in any solvent. That's fine.

  There are two types of light emission of the phosphorescent dopant in principle. One is the recombination of carriers on the host compound to which carriers are transported to generate an excited state of the luminescent host compound, and this energy is used as the phosphorescent dopant. It is an energy transfer type in which light emission from a phosphorescent dopant is obtained by moving to. The other is a carrier trap type in which a phosphorescent dopant serves as a carrier trap, carrier recombination occurs on the phosphorescent dopant, and light emission from the phosphorescent dopant compound is obtained. In any case, it is a condition that the excited state energy of the phosphorescent dopant is lower than the excited state energy of the host compound.

  The phosphorescent dopant used in the production method of the present invention has a phosphorescence lifetime of less than 1.4 μsec at room temperature (25 ° C.) in a film state dispersed in a light emitting host material contained in the light emitting layer, In addition, the phosphorescence quantum yield is 70% or more. A film in which a phosphorescent dopant is dispersed in a light emitting host material is co-evaporated on quartz glass at a ratio of light emitting host: phosphorescent dopant = 9: 1 to a thickness of 40 nm and sealed in an inert gas atmosphere. It is a film | membrane, The phosphorescence lifetime and phosphorescence quantum yield in this invention are the values obtained by measuring with respect to the said film | membrane by a well-known method.

  In the production method of the present invention, a blue light-emitting phosphorescent material having a light emission maximum in a wavelength region of 400 nm to 500 nm can be used.

(2.2) Phosphorescent dopant represented by general formula (1) The phosphorescent dopant represented by general formula (1) preferably used in the production method of the present invention will be described below, but the phosphorescent dopant used in the present invention. The optical dopant is not limited to this.

In the general formula (1), examples of the 5-membered or 6-membered aromatic hydrocarbon ring represented by the ring A and the ring B include a benzene ring.
In the general formula (1), examples of the 5-membered or 6-membered aromatic hydrocarbon ring represented by the ring A and the ring B include a furan ring, a thiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, a pyridazine ring, Examples include a pyrimidine ring, a pyrazine ring, a triazine ring, an oxadiazole ring, a triazole ring, an imidazole ring, a pyrazole ring, and a thiazole ring.
Preferably ring B is a benzene ring, more preferably ring A is a benzene ring.

  In the general formula (1), examples of the aromatic hydrocarbon ring represented by Ar include a benzene ring, biphenyl ring, naphthalene ring, azulene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring, naphthacene ring, and triphenylene. Ring, o-terphenyl ring, m-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, naphthacene ring, pentacene ring, perylene ring, pentaphen ring, picene ring, pyrene Ring, pyranthrene ring, anthraanthrene ring and the like.

  In the general formula (1), examples of the aromatic heterocycle represented by Ar include a silole ring, a furan ring, a thiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, and a triazine ring. Oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, benzimidazole ring, benzthiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, phthalazine ring, thienothiophene ring, carbazole ring, aza A carbazole ring (representing any one or more of the carbon atoms constituting the carbazole ring replaced by a nitrogen atom), a dibenzosilole ring, a dibenzofuran ring, a dibenzothiophene ring, a benzothiophene ring or a dibenzofuran ring. Any one Ring substituted with nitrogen atom, benzodifuran ring, benzodithiophene ring, acridine ring, benzoquinoline ring, phenazine ring, phenanthridine ring, phenanthroline ring, cyclazine ring, quindrine ring, tepenidine ring, quinindrin ring, triphenodithia Gin ring, triphenodioxazine ring, phenanthrazine ring, anthrazine ring, perimidine ring, naphthofuran ring, naphthothiophene ring, naphthodifuran ring, naphthodithiophene ring, anthrafuran ring, anthradifuran ring, anthrathiophene ring, anthradithiophene Ring, thianthrene ring, phenoxathiin ring, dibenzocarbazole ring, indolocarbazole ring, dithienobenzene ring and the like.

  In the general formula (1), examples of the non-aromatic hydrocarbon ring represented by Ar include cycloalkane (eg, cyclopentane ring, cyclohexane ring, etc.), cycloalkoxy group (eg, cyclopentyloxy group, cyclohexyloxy group). Etc.), a cycloalkylthio group (for example, a cyclopentylthio group, a cyclohexylthio group, etc.), a cyclohexylaminosulfonyl group, a tetrahydronaphthalene ring, a 9,10-dihydroanthracene ring, a biphenylene ring and the like.

  In the general formula (1), examples of the non-aromatic heterocycle represented by Ar include an epoxy ring, an aziridine ring, a thiirane ring, an oxetane ring, an azetidine ring, a thietane ring, a tetrahydrofuran ring, a dioxolane ring, a pyrrolidine ring, and a pyrazolidine. Ring, imidazolidine ring, oxazolidine ring, tetrahydrothiophene ring, sulfolane ring, thiazolidine ring, ε-caprolactone ring, ε-caprolactam ring, piperidine ring, hexahydropyridazine ring, hexahydropyrimidine ring, piperazine ring, morpholine ring, tetrahydropyran Ring, 1,3-dioxane ring, 1,4-dioxane ring, trioxane ring, tetrahydrothiopyran ring, thiomorpholine ring, thiomorpholine-1,1-dioxide ring, pyranose ring, diazabicyclo [2,2,2]- Octane ring, Fe Examples thereof include a noxazine ring, a phenothiazine ring, an oxanthrene ring, a thioxanthene ring, and a phenoxathiin ring.

  In these rings represented by Ar in the general formula (1), substituents may be bonded to each other to form a ring.

  Preferably, Ar in the general formula (1) is an aromatic hydrocarbon ring or an aromatic heterocyclic ring, more preferably an aromatic hydrocarbon ring, and still more preferably a benzene ring.

In the general formula (1), R1 and R2 are each independently a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an amino group, a silyl group, an arylalkyl group, an aryl group, a hetero group Represents an aryl group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent, and at least one of R 1 and R 2 is an alkyl group or a cycloalkyl group having 2 or more carbon atoms It is.
In the general formula (1), the aryl group and heteroaryl group represented by R1 and R2 are derived from the aromatic hydrocarbon ring and aromatic heterocycle represented by Ar in the general formula (1). A monovalent group is mentioned.
In the general formula (1), examples of the non-aromatic hydrocarbon ring group and non-aromatic heterocyclic group represented by R1 and R2 include the non-aromatic hydrocarbon ring represented by Ar in the general formula (1). And a monovalent group derived from a non-aromatic heterocyclic ring.
Preferably, R1 and R2 are both alkyl groups or cycloalkyl groups having 2 or more carbon atoms, and at least one of R1 and R2 is preferably a branched alkyl group having 3 or more carbon atoms. More preferably, R1 and R2 are both branched alkyl groups having 3 or more carbon atoms.

In the general formula (1), Ra, Rb and Rc are each independently a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an amino group, a silyl group, an arylalkyl group, an aryl group. Represents a heteroaryl group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent.
In the general formula (1), the aryl group and heteroaryl group represented by Ra, Rb and Rc are derived from the aromatic hydrocarbon ring and aromatic heterocycle represented by Ar in the general formula (1). And a monovalent group.
In the general formula (1), as the non-aromatic hydrocarbon ring group and non-aromatic heterocyclic group represented by Ra, Rb and Rc, the non-aromatic carbon represented by Ar in the above-mentioned general formula (1) And monovalent groups derived from a hydrogen ring and a non-aromatic heterocyclic ring.

  In general formula (1), na and nc represent 1 or 2, and nb represents an integer of 1 to 4.

  In the general formula (1), specific examples of the monoanionic bidentate ligand coordinated to M represented by L ′ include a ligand of the following formula.

  In the above formula, Rd ′, Rd ″ and Rd ′ ″ represent a hydrogen atom or a substituent. Examples of the substituent represented by Rd ′, Rd ″ and Rd ′ ″ include an alkyl group (for example, a methyl group). , Ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, etc.), alkenyl group (for example, vinyl group, allyl group, etc.) An alkynyl group (for example, ethynyl group, propargyl group, etc.), a non-aromatic hydrocarbon ring group (for example, cycloalkyl group (for example, cyclopentyl group, cyclohexyl group, etc.)), a cycloalkoxy group (for example, cyclopentyloxy group, cyclohexyloxy) Group), cycloalkylthio group (for example, cyclopentylthio group, cyclohexylthio group) Etc.), tetrahydronaphthalene ring, 9,10-dihydroanthracene ring, monovalent group derived from biphenylene ring, etc.), non-aromatic heterocyclic group (for example, epoxy ring, aziridine ring, thiirane ring, oxetane ring, azetidine Ring, thietane ring, tetrahydrofuran ring, dioxolane ring, pyrrolidine ring, pyrazolidine ring, imidazolidine ring, oxazolidine ring, tetrahydrothiophene ring, sulfolane ring, thiazolidine ring, ε-caprolactone ring, ε-caprolactam ring, piperidine ring, hexahydropyridazine Ring, hexahydropyrimidine ring, piperazine ring, morpholine ring, tetrahydropyran ring, 1,3-dioxane ring, 1,4-dioxane ring, trioxane ring, tetrahydrothiopyran ring, thiomorpholine ring, thiomorpholine-1,1- Dioqui A monovalent group derived from a ring, a pyranose ring, a diazabicyclo [2,2,2] -octane ring, a phenoxazine ring, a phenothiazine ring, an oxanthrene ring, a thioxanthene ring, a phenoxathiin ring), an aromatic carbonization Hydrogen group (for example, benzene ring, biphenyl ring, naphthalene ring, azulene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring, naphthacene ring, triphenylene ring, o-terphenyl ring, m-terphenyl ring, p-terium Monovalent derived from phenyl ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, naphthacene ring, pentacene ring, perylene ring, pentaphen ring, picene ring, pyrene ring, pyranthrene ring, anthraanthrene ring, etc. Group), aromatic heterocyclic group (for example, silole ring, furan ring, thiophene) Oxazole ring, pyrrole ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, benzimidazole ring, benzthiazole ring, Benzoxazole ring, quinoxaline ring, quinazoline ring, phthalazine ring, thienothiophene ring, carbazole ring, azacarbazole ring (representing any one or more of the carbon atoms constituting the carbazole ring replaced by a nitrogen atom), dibenzosilole Ring, dibenzofuran ring, dibenzothiophene ring, benzothiophene ring or ring in which any one of carbon atoms constituting dibenzofuran ring is replaced by nitrogen atom, benzodifuran ring, benzodithiophene ring, acridine ring, benzoquinoline Ring, phenazine ring, phenanthridine ring, phenanthroline ring, cyclazine ring, kindrin ring, tepenidine ring, quinindrine ring, triphenodithiazine ring, triphenodioxazine ring, phenanthrazine ring, anthrazine ring, perimidine ring, naphthofuran ring, Naphthothiophene ring, naphthodifuran ring, naphthodithiophene ring, anthrafuran ring, anthradifuran ring, anthrathiophene ring, anthradithiophene ring, thianthrene ring, phenoxathiin ring, dibenzocarbazole ring, indolocarbazole ring, dithienobenzene A monovalent group derived from a ring, etc.), an alkoxy group (for example, a methoxy group, an ethoxy group, a propyloxy group, a pentyloxy group, a hexyloxy group, an octyloxy group, a dodecyloxy group, etc.), an aryloxy group ( For example, phenoxy group, naphthyloxy group, etc.), alkylthio group (eg, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), arylthio group (eg, phenylthio group, naphthylthio group, etc.) ), Alkoxycarbonyl groups (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl groups (eg, phenyloxycarbonyl group, naphthyloxycarbonyl) Group), sulfamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclo Xylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), acyl group (for example, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentyl) Carbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (for example, acetyloxy group, ethylcarbonyloxy group, butyl) Carbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide group (for example, methylcarbonylamino group) , Ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonyl Amino group, etc.), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group) , Dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl Ureido group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group, naphthylureido group, 2-pyridylaminoureido group), sulfinyl group (For example, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc.), alkylsulfonyl group (for example, Methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), aryl Sulfonyl group or heteroarylsulfonyl group (for example, phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (for example, amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridylamino group, etc.), halogen atom (for example, fluorine atom, chlorine atom, bromine atom, fluorinated hydrocarbon group (for example, fluoromethyl group, Trifluoromethyl group, pentafluoroethyl group, pentafluorophenyl group, etc.), cyano group, nitro group, hydroxy group, mercapto group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group, phenyldiethylsilyl) Group) And phosphono group.

  In the general formula (1), M is an atomic number of 40 or more and a transition metal atom of Group 8 to 10 in the periodic table of elements. Os, Ir, and Pt are preferable, and Ir is more preferable.

In the general formula (1), m ′ represents an integer of 0 to 2, n ′ is at least 1, and m ′ + n ′ represents 2 or 3.
Preferably, n ′ is 3 or 2, and m ′ is 0.

(2.3) Specific Example The compound represented by the general formula (1) used in the production method of the present invention can be synthesized by referring to a known method described in International Publication No. 2006-121811, etc.

  Although the specific example of the phosphorescence dopant compound which can be preferably used in this invention below is given, this invention is not limited to these.

<< Injection layer: electron injection layer, hole injection layer >>
The injection layer is provided as necessary, and there are an electron injection layer and a hole injection layer, and as described above, it exists between the anode and the light emitting layer or the hole transport layer and between the cathode and the light emitting layer or the electron transport layer. May be.

  An injection layer is a layer provided between an electrode and an organic layer in order to reduce drive voltage and improve light emission luminance. “Organic EL element and its forefront of industrialization (issued by NTT Corporation on November 30, 1998) 2), Chapter 2, “Electrode Materials” (pages 123 to 166) in detail, and includes a hole injection layer (anode buffer layer) and an electron injection layer (cathode buffer layer).

  The details of the anode buffer layer (hole injection layer) are described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069 and the like. As a specific example, copper phthalocyanine is used. Examples thereof include a phthalocyanine buffer layer represented by an oxide, an oxide buffer layer represented by vanadium oxide, an amorphous carbon buffer layer, and a polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene.

  The details of the cathode buffer layer (electron injection layer) are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specifically, strontium, aluminum, etc. Metal buffer layer typified by lithium, alkali metal compound buffer layer typified by lithium fluoride, alkaline earth metal compound buffer layer typified by magnesium fluoride, oxide buffer layer typified by aluminum oxide, etc. . The buffer layer (injection layer) is preferably a very thin film, and the film thickness is preferably in the range of 0.1 nm to 5 μm although it depends on the material.

<Blocking layer: hole blocking layer, electron blocking layer>
The blocking layer is provided as necessary in addition to the basic constituent layer of the organic compound thin film as described above. For example, it is described in JP-A Nos. 11-204258, 11-204359, and “Organic EL elements and their forefront of industrialization” (issued by NTT, Inc. on November 30, 1998). There is a hole blocking (hole blocking) layer.

  The hole blocking layer has a function of an electron transport layer in a broad sense, and is made of a hole blocking material that has a function of transporting electrons and has a remarkably small ability to transport holes. The probability of recombination of electrons and holes can be improved by blocking. Moreover, the structure of the electron carrying layer mentioned later can be used as a hole-blocking layer concerning this invention as needed.

  The hole blocking layer of the organic EL device of the present invention is preferably provided adjacent to the light emitting layer.

  The hole blocking layer preferably contains the azacarbazole derivative mentioned as the host compound.

  In the present invention, when a plurality of light emitting layers having different light emission colors are provided, the light emitting layer having the shortest wavelength of light emission is preferably closest to the anode among all the light emitting layers. In this case, it is preferable to additionally provide a hole blocking layer between the shortest wave layer and the light emitting layer next to the anode next to the anode. Furthermore, it is preferable that 50% by mass or more of the compound contained in the hole blocking layer provided at the position has an ionization potential of 0.3 eV or more larger than the host compound of the shortest wave emitting layer.

The ionization potential is defined by the energy required to emit an electron at the HOMO (highest occupied molecular orbital) level of the compound to the vacuum level, and can be obtained by the following method, for example.
(1) Using Gaussian 98 (Gaussian 98, Revision A.11.4, MJ Frisch, et al, Gaussian, Inc., Pittsburgh PA, 2002.), a molecular orbital calculation software manufactured by Gaussian, USA The ionization potential can be obtained as a value obtained by rounding off the second decimal place of the value (eV unit converted value) calculated by performing structural optimization using B3LYP / 6-31G *. This calculation value is effective because the correlation between the calculation value obtained by this method and the experimental value is high.
(2) The ionization potential can also be obtained by a method of directly measuring by photoelectron spectroscopy. For example, a method known as ultraviolet photoelectron spectroscopy can be suitably used by using a low energy electron spectrometer “Model AC-1” manufactured by Riken Keiki Co., Ltd.

  On the other hand, the electron blocking layer has a function of a hole transport layer in a broad sense, and is made of a material having a function of transporting holes while having a very small ability to transport electrons, and transporting electrons while transporting holes. By blocking, the recombination probability of electrons and holes can be improved. Moreover, the structure of the positive hole transport layer mentioned later can be used as an electron blocking layer as needed. The film thickness of the hole blocking layer and the electron transport layer according to the present invention is preferably 3 nm to 100 nm, and more preferably 5 nm to 30 nm.

《Hole transport layer》
The hole transport layer is made of a hole transport material having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. The hole transport layer can be provided as a single layer or a plurality of layers.

The hole transport material has any one of hole injection or transport and electron barrier properties, and may be either organic or inorganic. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples thereof include stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers.

  The above-mentioned materials can be used as the hole transport material, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound.

  Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ', N'-tetraphenyl-4,4'-diaminophenyl; N, N'-diphenyl-N, N'- Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl; 1,1-bis (4-di-p-tolyl) Aminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N'-diphenyl-N, N ' − (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadriphenyl; N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4′-N, N-diphenylaminostilbenzene; N-phenylcarbazole, and also two of those described in US Pat. No. 5,061,569. Having a condensed aromatic ring in the molecule, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-3086 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 8 are linked in a starburst type ( MTDATA) and the like.

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material.

  JP-A-11-251067, J. Org. Huang et. al. A so-called p-type hole transport material as described in a book (Applied Physics Letters 80 (2002), p. 139) can also be used. In the present invention, these materials are preferably used because a light-emitting element with higher efficiency can be obtained.

The hole transport layer can be formed by thinning the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. it can.
Although there is no restriction | limiting in particular about the film thickness of a positive hole transport layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5 nm-200 nm. The hole transport layer may have a single layer structure composed of one or more of the above materials.

Alternatively, a hole transport layer having a high p property doped with impurities can be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, 2001-102175, J. Pat. Appl. Phys. 95, 5773 (2004), and the like.
In the present invention, it is preferable to use a hole transport layer having such a high p property because a device with lower power consumption can be produced.

《Electron transport layer》
The electron transport layer is made of a material having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. The electron transport layer can be provided as a single layer or a plurality of layers.

  Conventionally, in the case of a single electron transport layer and a plurality of layers, an electron transport material (also serving as a hole blocking material) used for an electron transport layer adjacent to the light emitting layer on the cathode side is injected from the cathode. As long as it has a function of transferring electrons to the light-emitting layer, any material can be selected and used from among conventionally known compounds. For example, nitro-substituted fluorene derivatives, diphenylquinone derivatives Thiopyrandioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives and the like. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  Also, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum, Tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), etc., and the central metals of these metal complexes are In, Mg, Cu , Ca, Sn, Ga, or Pb can also be used as an electron transport material.

  In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transporting material.

  In addition, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and an inorganic semiconductor such as n-type-Si, n-type-SiC, etc. as in the case of the hole injection layer and the hole transport layer. Can also be used as an electron transporting material.

The electron transport layer can be formed by thinning the electron transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method.
Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5 nm-200 nm. The electron transport layer may have a single layer structure composed of one or more of the above materials.

It is also possible to use an electron transport layer having a high n property doped with impurities. Examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.
In the present invention, it is preferable to use an electron transport layer having such a high n property because an element with lower power consumption can be manufactured.

"anode"
As the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such electrode materials include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO.

Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used. For the anode, these electrode materials may be formed into a thin film by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or when pattern accuracy is not so high (about 100 μm or more) A pattern may be formed through a mask having a desired shape at the time of vapor deposition or sputtering of the electrode material.

  Or when using the substance which can be apply | coated like an organic electroconductivity compound, wet film-forming methods, such as a printing system and a coating system, can also be used. When light emission is extracted from the anode, it is desirable that the transmittance be greater than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 nm to 1000 nm, preferably 10 nm to 200 nm.

"cathode"
On the other hand, as the cathode, a material having a low work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred.

  The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as a cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 nm to 200 nm.

In order to transmit the emitted light, if either one of the anode or the cathode of the organic EL element is transparent or translucent, the light emission luminance is improved, which is convenient.
Moreover, after producing the said metal by the film thickness of 1 nm-20 nm to a cathode, the transparent or semi-transparent cathode can be produced by producing the electroconductive transparent material quoted by description of the anode on it, By applying this, an element in which both the anode and the cathode are transmissive can be manufactured.

《Support substrate》
As a support substrate (hereinafter also referred to as a substrate, substrate, substrate, support, etc.) that can be used in the organic EL device of the present invention, there is no particular limitation on the type of glass, plastic, etc., and it is transparent. May be opaque. When extracting light from the support substrate side, the support substrate is preferably transparent.
Examples of the transparent support substrate preferably used include glass, quartz, and a transparent resin film. A particularly preferable support substrate is a resin film capable of giving flexibility to the organic EL element.

  Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose acetate propionate (CAP), Cellulose esters such as cellulose acetate phthalate (TAC) and cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide , Polyethersulfone (PES), polyphenylene sulfide, polysulfones Cycloolefin resins such as polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic or polyarylate, Arton (trade name, manufactured by JSR) or Appel (trade name, manufactured by Mitsui Chemicals) Can be mentioned.

An inorganic or organic film or a hybrid film of both may be formed on the surface of the resin film, and a barrier film having a water vapor permeability of 0.01 g / m ² / day · atm or less is preferable. Furthermore, a high barrier film having an oxygen permeability of 10 ⁻³ g / m ² / day or less and a water vapor permeability of 10 ⁻⁵ g / m ² / day or less is preferable.

  As a material for forming the barrier film, any material may be used as long as it has a function of suppressing entry of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like can be used. Further, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and organic material layers. Although there is no restriction | limiting in particular about the lamination | stacking order of an inorganic layer and an organic layer, It is preferable to laminate | stack both alternately several times.

  The method for forming the barrier film is not particularly limited. For example, the vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma weight A combination method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, and the like can be used, but an atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferable.

  Examples of the opaque support substrate include metal plates such as aluminum and stainless steel, films, opaque resin substrates, and ceramic substrates.

  The external extraction efficiency at room temperature of light emission of the organic EL device of the present invention is preferably 1% or more, more preferably 5% or more. Here, external extraction quantum efficiency (%) = number of photons emitted to the outside of the organic EL element / number of electrons flowed to the organic EL element × 100.

  In addition, a hue improvement filter such as a color filter may be used in combination, or a color conversion filter that converts the emission color from the organic EL element into multiple colors using a phosphor. In the case of using a color conversion filter, the λmax of light emission of the organic EL element is preferably 480 nm or less.

<Sealing>
As a sealing means used for this invention, the method of adhere | attaching a sealing member, an electrode, and a support substrate with an adhesive agent can be mentioned, for example.

  As a sealing member, it should just be arrange | positioned so that the display area | region of an organic EL element may be covered, and concave plate shape or flat plate shape may be sufficient. Further, transparency and electrical insulation are not particularly limited.

  Specific examples include a glass plate, a polymer plate / film, and a metal plate / film. Examples of the glass plate include soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and polysulfone. Examples of the metal plate include those made of one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium, and tantalum.

In the present invention, a polymer film and a metal film can be preferably used because the element can be thinned. Furthermore, the polymer film, measured oxygen permeability by the method based on JIS K 7126-1987 is ^{1 × 10 -3 ml / m 2} / 24h or less, as measured by the method based on JIS K 7129-1992 water vapor transmission rate (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH is preferably intended ^{1 × 10 -3 g / (m} 2 / 24h) or less.

  For processing the sealing member into a concave shape, sandblasting, chemical etching, or the like is used.

  Specific examples of the adhesive include photocuring and thermosetting adhesives having reactive vinyl groups such as acrylic acid oligomers and methacrylic acid oligomers, and moisture curing adhesives such as 2-cyanoacrylates. be able to. Moreover, heat | fever and chemical curing types (two-component mixing), such as an epoxy type, can be mentioned. Moreover, hot-melt type polyamide, polyester, and polyolefin can be mentioned. Moreover, a cationic curing type ultraviolet curing epoxy resin adhesive can be mentioned.

  In addition, since an organic EL element may deteriorate by heat processing, what can be adhesive-hardened from room temperature to 80 degreeC is preferable. A desiccant may be dispersed in the adhesive. Application | coating of the adhesive agent to a sealing part may use commercially available dispenser, and may print like screen printing.

  In addition, it is also preferable that the electrode and the organic layer are coated on the outside of the electrode facing the support substrate with the organic layer interposed therebetween, and an inorganic or organic layer is formed in contact with the support substrate to form a sealing film. . In this case, the material for forming the film may be any material that has a function of suppressing intrusion of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like may be used. it can. Further, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of organic materials. The method for forming these films is not particularly limited. For example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster-ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma A polymerization method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.

  In the gap between the sealing member and the display area of the organic EL element, an inert gas such as nitrogen or argon, or an inert liquid such as fluorinated hydrocarbon or silicon oil can be injected in the gas phase and liquid phase. preferable. A vacuum is also possible. Moreover, a hygroscopic compound can also be enclosed inside.

Examples of the hygroscopic compound include metal oxides (for example, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide) and sulfates (for example, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate). Etc.), metal halides (eg calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide etc.), perchloric acids (eg perchloric acid) Barium, magnesium perchlorate, and the like), and anhydrous salts are preferably used in sulfates, metal halides, and perchloric acids.

《Protective film, protective plate》
In order to increase the mechanical strength of the element, a protective film or a protective plate may be provided on the outer side of the sealing film on the side facing the support substrate with the organic layer interposed therebetween or on the sealing film. In particular, when the sealing is performed by the sealing film, the mechanical strength is not necessarily high, and thus it is preferable to provide such a protective film and a protective plate. As a material that can be used for this, the same glass plate, polymer plate / film, metal plate / film, and the like used for the sealing can be used, but the polymer film is light and thin. Is preferably used.

《Light extraction》
The organic EL element emits light inside a layer having a refractive index higher than that of air (refractive index is about 1.7 to 2.1) and can extract only about 15% to 20% of the light generated in the light emitting layer. It is generally said. This is because light incident on the interface (interface between the transparent substrate and air) at an angle θ greater than the critical angle causes total reflection and cannot be taken out of the device, or between the transparent electrode or light emitting layer and the transparent substrate. This is because the light is totally reflected between the light and the light is guided through the transparent electrode or the light emitting layer, and as a result, the light escapes in the direction of the element side surface.

  As a method for improving the light extraction efficiency, for example, a method of forming irregularities on the surface of the transparent substrate to prevent total reflection at the interface between the transparent substrate and the air (US Pat. No. 4,774,435), A method of improving efficiency by providing a light collecting property to a substrate (Japanese Patent Laid-Open No. 63-314795), a method of forming a reflective surface on a side surface of an element (Japanese Patent Laid-Open No. 1-220394), and light emission from a substrate A method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between the bodies (Japanese Patent Laid-Open No. 62-172691), a flat having a lower refractive index between the substrate and the light emitter than the substrate A method of introducing a layer (Japanese Patent Laid-Open No. 2001-202827), a method of forming a diffraction grating between any one of a substrate, a transparent electrode layer and a light emitting layer (including between the substrate and the outside) (Japanese Patent Laid-Open No. 11-283951) Gazette).

  In the present invention, these methods can be used in combination with the organic EL device of the present invention. However, a method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light emitter, or a substrate, transparent A method of forming a diffraction grating between any layers of the electrode layer and the light emitting layer (including between the substrate and the outside) can be suitably used.

  In the present invention, by combining these means, it is possible to obtain an element having higher luminance or durability.

  When a medium having a low refractive index is formed between the transparent electrode and the transparent substrate with a thickness longer than the wavelength of light, the light extracted from the transparent electrode has a higher extraction efficiency to the outside as the refractive index of the medium is lower.

  Examples of the low refractive index layer include aerogel, porous silica, magnesium fluoride, and a fluorine-based polymer. Since the refractive index of the transparent substrate is generally about 1.5 to 1.7, the low refractive index layer preferably has a refractive index of about 1.5 or less. Further, it is preferably 1.35 or less.

  The thickness of the low refractive index medium is preferably at least twice the wavelength in the medium. This is because the effect of the low refractive index layer is diminished when the thickness of the low refractive index medium is about the wavelength of light and the electromagnetic wave that has exuded by evanescent enters the substrate.

  The method of introducing a diffraction grating into an interface or any medium that causes total reflection is characterized by a high effect of improving light extraction efficiency. This method uses the property that the diffraction grating can change the direction of light to a specific direction different from refraction by so-called Bragg diffraction such as first-order diffraction and second-order diffraction. Light that cannot be emitted due to total internal reflection between layers is diffracted by introducing a diffraction grating in any layer or medium (in a transparent substrate or transparent electrode), and the light is removed. I want to take it out.

  The introduced diffraction grating desirably has a two-dimensional periodic refractive index. This is because light emitted from the light-emitting layer is randomly generated in all directions, so in a general one-dimensional diffraction grating having a periodic refractive index distribution only in a certain direction, only light traveling in a specific direction is diffracted. Therefore, the light extraction efficiency does not increase so much. However, by making the refractive index distribution a two-dimensional distribution, light traveling in all directions is diffracted, and light extraction efficiency is increased.

  As described above, the position where the diffraction grating is introduced may be in any of the layers or in the medium (in the transparent substrate or in the transparent electrode), but is preferably in the vicinity of the organic light emitting layer where light is generated.

  At this time, the period of the diffraction grating is preferably about 1/2 to 3 times the wavelength of light in the medium.

  The arrangement of the diffraction grating is preferably two-dimensionally repeated, such as a square lattice, a triangular lattice, or a honeycomb lattice.

<Condenser sheet>
The organic EL device of the present invention is processed on the light extraction side of the substrate so as to provide, for example, a microlens array structure, or combined with a so-called condensing sheet, for example, with respect to a specific direction, for example, the device light emitting surface. By condensing in the front direction, the luminance in a specific direction can be increased.

  As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are two-dimensionally arranged on the light extraction side of the substrate. One side is preferably 10 μm to 100 μm. If it becomes smaller than this, the effect of diffraction will generate | occur | produce and color, and if too large, thickness will become thick and is not preferable.

As the condensing sheet, for example, a sheet that is put into practical use in an LED backlight of a liquid crystal display device can be used. As such a sheet, for example, a brightness enhancement film (BEF) manufactured by Sumitomo 3M Limited can be used.
As the shape of the prism sheet, for example, the base material may be formed by forming a △ -shaped stripe having a vertex angle of 90 degrees and a pitch of 50 μm, or the vertex angle is rounded and the pitch is changed randomly. Other shapes may be used.

  Moreover, in order to control the light emission angle from a light emitting element, you may use together a light diffusing plate and a film with a condensing sheet. For example, a diffusion film (light-up) manufactured by Kimoto Co., Ltd. can be used.

<< Method for producing organic EL element >>
In the method for producing an organic EL device of the present invention, a part or the whole of an organic layer sandwiched between an anode and a cathode is formed by a wet process, and the wet process is an oxygen concentration of 10 to 2000 ppm and a moisture concentration of 10 to 2000 ppm. Perform under an active gas atmosphere.

  As an example of the method for producing the organic EL device of the present invention, a method for producing an organic EL device comprising an anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode will be described.

  First, a desired electrode material, for example, a thin film made of an anode material is formed on a suitable substrate so as to have a film thickness of 1 μm or less, preferably 10 nm to 200 nm, to form an anode.

  Next, an organic compound thin film of a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and a hole blocking layer, which are organic EL element materials, is formed thereon.

  As a method for forming each of these layers, there are a vapor deposition method, a wet process (spin coating method, casting method, ink jet method, spray method, printing method) and the like as described above. In the present invention, film formation by a coating method such as a spin coating method, an ink jet method, a spray method, or a printing method is preferable from the viewpoint of being difficult to produce. Furthermore, the inkjet method and the spray method are more preferable from the viewpoint of mixing a plurality of solutions on the substrate.

Examples of the liquid medium for dissolving or dispersing the organic EL material according to the present invention include ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, halogenated hydrocarbons such as dichlorobenzene, toluene, xylene, and mesitylene. Aromatic hydrocarbons such as cyclohexylbenzene, aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane, and organic solvents such as DMF and DMSO can be used.
Moreover, as a dispersion method, it can disperse | distribute by dispersion methods, such as an ultrasonic wave, high shear force dispersion | distribution, and media dispersion | distribution.

  After these layers are formed, a thin film made of a cathode material is formed thereon by 1 μm or less, preferably by a method such as vapor deposition or sputtering so that the film thickness is in the range of 50 nm to 200 nm. By providing, a desired organic EL element can be obtained.

  In addition, it is also possible to reverse the production order and produce the cathode, the electron injection layer, the electron transport layer, the light emitting layer, the hole transport layer, the hole injection layer, and the anode in this order.

  When a DC voltage is applied to the multicolor display device thus obtained, light emission can be observed by applying a voltage of about 2 to 40 V with the positive polarity of the anode and the negative polarity of the cathode. An alternating voltage may be applied. The alternating current waveform to be applied may be arbitrary.

<Application>
The organic EL element of the present invention can be used as a display device, a display, and various light emission sources. For example, lighting devices (home lighting, interior lighting), clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources of optical storage media, light sources of electrophotographic copying machines, light sources of optical communication processors, light Although the light source of a sensor etc. are mentioned, It is not limited to this, Especially, it can use effectively for the use as a backlight of a liquid crystal display device, and a light source for illumination.

  In the organic EL element of the present invention, patterning may be performed by a metal mask, an ink jet printing method, or the like as needed during film formation. In the case of patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire layer of the element may be patterned. In the fabrication of the element, a conventionally known method is used. Can do.

  The light emission color of the organic EL device of the present invention and the compound according to the present invention is shown in FIG. 4.16 on page 108 of “New Color Science Handbook” (edited by the Japan Color Society, University of Tokyo Press, 1985). It is determined by the color when the result measured with the total CS-1000 (manufactured by Konica Minolta Sensing) is applied to the CIE chromaticity coordinates.

Further, when the organic EL device of the present invention is a white device, white means that the chromaticity in the CIE1931 color system at 1000 Cd / m ² is X when the 2 ° viewing angle front luminance is measured by the above method. = 0.33 ± 0.07 and Y = 0.33 ± 0.1.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.
The chemical formulas of the compounds used in the examples are shown below.

<< Production of organic EL element >>
(1) Preparation of organic EL element 101 After patterning on a substrate (NH technoglass NA45) formed by depositing ITO (indium tin oxide) 100 nm as an anode on a 100 mm × 100 mm × 1.1 mm glass substrate, The substrate provided with the ITO transparent electrode was subjected to ultrasonic cleaning with isopropyl alcohol, dried with dry nitrogen gas, and UV ozone cleaning was performed for 5 minutes.

  On this substrate, a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water was used at 3000 rpm for 30 seconds. After forming the film by spin coating under the conditions, the film was dried at a substrate surface temperature of 200 ° C. for 1 hour to provide a hole injection layer having a thickness of 30 nm.

This substrate was transferred into a glove box under a nitrogen atmosphere in accordance with JIS B 9920, the measured cleanliness was class 100, and the oxygen concentration was 10 ppm and the water concentration was 10 ppm. The hole transport layer, the light emitting layer, and the electron transport layer described below are all formed in the glove box.
A hole transport layer coating solution was prepared as follows in a glove box, and the prepared hole transport layer coating solution was applied to the substrate using a spin coater under conditions of 1500 rpm and 30 seconds. This substrate was dried by heating at a substrate surface temperature of 150 ° C. for 30 minutes to provide a hole transport layer. The film thickness was 20 nm when it apply | coated and measured on the conditions with respect to the board | substrate prepared separately.
The coating solution for the hole transport layer is 100 g of monochlorobenzene, poly- (N, N′-bis (4-butylphenyl) -N, N′-bis (phenyl) benzidine) (ADS254BE: American Die Source) Prepared by mixing 0.5 g).

Next, a light-emitting layer coating solution was prepared as follows (preparation step), and the prepared light-emitting layer coating solution was applied to the substrate using a spin coater under the conditions of 2000 rpm and 30 seconds. A light emitting layer was provided by heating at a temperature of 120 ° C. for 30 minutes (application process). The film thickness was 40 nm when it apply | coated and measured on the conditions with respect to the board | substrate prepared separately.
The coating solution for the light emitting layer is prepared by mixing 100 g of butyl acetate, 1 g of H-1 as a host compound, and 0.11 g of D-1 as a phosphorescent dopant.

Next, an electron transport layer coating solution was prepared as described below, and the prepared electron transport layer coating solution was applied to the substrate under conditions of 1500 rpm and 30 seconds using a spin coater. Furthermore, it heated for 30 minutes at the substrate surface temperature of 120 degreeC, and provided the electron carrying layer. The film thickness was 30 nm when it apply | coated and measured on the conditions with respect to the board | substrate prepared separately.
The coating solution for the electron transport layer is prepared by mixing 100 g of 2,2,3,3-tetrafluoro-1-propanol and 0.75 g of ET-A.

Next, the substrate provided up to the electron transport layer was moved to a vapor deposition machine without being exposed to the atmosphere, and the pressure was reduced to 4 × 10 ⁻⁴ Pa. Note that potassium fluoride and aluminum were each placed in a tantalum resistance heating boat and attached to a vapor deposition machine.
First, a resistance heating boat containing potassium fluoride was energized and heated, and an electron injection layer having a thickness of 3 nm made of potassium fluoride was provided on the substrate. Subsequently, the resistance heating boat containing aluminum was energized and heated to provide a cathode having a thickness of 100 nm made of aluminum at a deposition rate of 1 to 2 nm / second.

  The substrate provided up to the cathode is moved to a glove box with a cleanness measured in accordance with JIS B9920 in a nitrogen atmosphere in accordance with JIS B9920 without exposure to the atmosphere, and moved to a glove box having an oxygen concentration of 10 ppm and a moisture concentration of 10 ppm. Sealing was performed with a glass sealing can attached with barium oxide to obtain an organic EL element 101, which was used as a sample. Barium oxide, a water-absorbing agent, is a high-purity barium oxide powder manufactured by Aldrich, and is attached to a glass sealing can with a fluorine-based semipermeable membrane (Microtex S-NTF8031Q manufactured by Nitto Denko) with an adhesive. Were prepared and used in advance. An ultraviolet curable adhesive was used for bonding the sealing can and the organic EL element, and both were bonded to each other by irradiating ultraviolet rays to produce a sealing element.

(2) Preparation of organic EL elements 102 to 124 In the preparation of organic EL element 101, the phosphorescent dopant used for the light emitting layer, the oxygen concentration and the moisture concentration in the glove box used when preparing the organic EL element are as shown in Table 1. changed.
Other than that produced the organic EL elements 102-124 similarly.

<< Evaluation of organic EL elements >>
The following evaluation was performed about the organic EL elements 101-124 obtained in this way. The evaluation results are shown in Table 1.

(1) External extraction quantum efficiency (luminescence efficiency)
External quantum efficiency (%) was measured when a constant current of ^2.5 mA / cm ² was applied to the produced organic EL element. For the measurement, a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing) was used. The external extraction quantum efficiencies of the organic EL elements 102 to 106 are expressed as relative values with the measured value of the organic EL element 101 as 100.

  The external extraction quantum efficiencies of the organic EL elements 108 to 112 are relative values where the measurement value of the organic EL element 107 is 100, and the external extraction quantum efficiencies of the organic EL elements 114 to 118 are the measurement values of the organic EL element 113. The relative value taken as 100 and the external extraction quantum efficiency of the organic EL elements 120 to 124 were expressed as relative values with the measured value of the organic EL element 119 taken as 100, respectively.

(2) Luminescence Life A current that gives a front luminance of 1000 cd / m ² was applied to the produced organic EL element and continuously driven. The time required for the front luminance to reach the initial half value (500 cd / m ² ) was determined, and the light emission lifetimes of the organic EL elements 102 to 106 were expressed as relative values with the measured value of the organic EL element 101 as 100.

  The light emission lifetimes of the organic EL elements 108 to 112 are relative values with the measured value of the organic EL element 107 as 100, and the light emission lifetimes of the organic EL elements 114 to 118 are relative with the measured value of the organic EL element 113 as 100. The light emission lifetimes of the organic EL elements 120 to 124 are expressed as relative values with the measured value of the organic EL element 119 as 100.

(3) Summary From the results shown in Table 1, according to the manufacturing method of the present invention, an organic EL device having high luminous efficiency and long life can be obtained by a wet process even in an oxygen concentration and moisture concentration environment where mass production is feasible. It can be seen that it can be manufactured.

<< Preparation of white organic EL element >>
(1) Production of white organic EL element 201 The coating solution for the light emitting layer is 100 g of butyl acetate, 1 g of H-1 as a host compound, 0.11 g of D-3 as a blue phosphorescent dopant, and D as a green phosphorescent dopant. It was prepared by mixing 0.002 g of -1 and 0.002 g of D-4 as a red phosphorescent dopant.
Other than that, the white organic EL element 201 was produced by the same method as the organic EL element 101 of Example 1.

(2) Preparation of white organic EL elements 202 to 212 In preparation of the organic EL element 201, the blue phosphorescent dopant used for the light-emitting layer, the oxygen concentration and the moisture concentration in the glove box used when preparing the organic EL element are shown in Table 2. Changed to street.
Other than that produced the organic EL elements 202-212 similarly.

<< Evaluation of white organic EL element >>
The following evaluations were performed on the white organic EL elements 201 to 212 thus obtained. The evaluation results are shown in Table 2.

(1) External extraction quantum efficiency (luminescence efficiency)
External quantum efficiency (%) was measured when a constant current of ^2.5 mA / cm ² was applied to the produced white organic EL element. For the measurement, a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing) was used. The external extraction quantum efficiencies of the white organic EL elements 202 to 206 were expressed as relative values with the measured value of the white organic EL element 201 being 100.
The external extraction quantum efficiencies of the white organic EL elements 208 to 212 are expressed as relative values with the measured value of the white organic EL element 207 as 100.

(2) Luminous lifetime A current that gives a front luminance of 1000 cd / m ² was applied to the produced white organic EL device and continuously driven. The time required for the front luminance to reach the initial half value (500 cd / m ² ) is obtained, and the light emission lifetimes of the white organic EL elements 202 to 206 are expressed as relative values with the measured value of the white organic EL element 201 as 100. did.
The light emission lifetimes of the white organic EL elements 208 to 212 are expressed as relative values with the measured value of the white organic EL element 207 as 100.

(3) Summary From the results shown in Table 2, according to the production method of the present invention, a white organic EL device having high luminous efficiency and long life due to a wet process even in an oxygen concentration and moisture concentration environment capable of mass production. It can be seen that can be manufactured.

Claims (4)

In the method of manufacturing an organic electroluminescence element, a light emitting layer containing at least a phosphorescent material is sandwiched between an anode and a cathode, and the light emitting layer is formed by a wet process.
A phosphorescent material dispersed in the light-emitting host material contained in the light-emitting layer and having a phosphorescence lifetime at room temperature in a film state of less than 1.4 μsec and a phosphorescence quantum yield of 70% or more is included. Adjusting the coating solution;
Applying the coating solution in an inert gas atmosphere having an oxygen concentration of 10 to 2000 ppm and a moisture concentration of 10 to 2000 ppm, and drying the coating solution.   The method for producing an organic electroluminescent element according to claim 1, wherein the phosphorescent material is a blue-emitting phosphorescent material having an emission maximum in a wavelength range of 400 nm to 500 nm. The said phosphorescence-emitting material is represented by following General formula (1), The manufacturing method of the organic electroluminescent element of Claim 1 or 2 characterized by the above-mentioned.

[In General Formula (1), Ring A and Ring B represent a 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocycle, and Ar represents an aromatic hydrocarbon ring, aromatic heterocycle, non-aromatic carbonization. Represents a hydrogen ring or a non-aromatic heterocyclic ring. R1 and R2 are each independently a hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl group, non-aromatic carbonization It represents a hydrogen ring group or a non-aromatic heterocyclic group, and may further have a substituent, and at least one of R1 and R2 is an alkyl group or a cycloalkyl group. Ra, Rb and Rc are each independently a hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl group, non-aromatic Represents a hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent. na and nc represent 1 or 2, and nb represents an integer of 1 to 4. L ′ is one or more of monoanionic bidentate ligands coordinated to M, M represents a transition metal atom of atomic number 40 or more and group 8 to 10 in the periodic table, m 'Represents an integer of 0 to 2, n' is at least 1, and m '+ n' is 2 or 3. ] In the organic electroluminescent element manufactured by the manufacturing method of the organic electroluminescent element according to any one of claims 1 to 3,
An organic electroluminescence device characterized in that the emission color is white.