JP5998745B2 - ORGANIC ELECTROLUMINESCENT ELEMENT, DISPLAY DEVICE, LIGHTING DEVICE, AND METHOD FOR PRODUCING ORGANIC ELECTROLUMINESCENT ELEMENT - Google Patents

Description

  The present invention relates to an organic electroluminescence element, a display device, a lighting device, and a method for manufacturing an organic electroluminescence element.

  Conventionally, an electroluminescence display (ELD) is known as a light-emitting electronic display device. Examples of the constituent elements of ELD include inorganic electroluminescence elements (inorganic EL elements) and organic electroluminescence elements (organic EL elements).

  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 EL element has a structure in which a light emitting layer containing a compound that emits light is sandwiched between a cathode and an anode, and excitons (exciton) are injected by injecting electrons and holes into the light emitting layer and recombining them. ) And emits light by utilizing light emission (fluorescence / phosphorescence) when the exciton is deactivated. Light emission is possible at a voltage of several volts to several tens of volts, and since it is a self-luminous type, it has a wide viewing angle, high visibility, and since it is a thin-film type complete solid-state device, it saves space and is portable. It attracts attention from the viewpoint of sex. Furthermore, the organic EL element has a feature that it is a surface light source.

  Applications that can effectively utilize this characteristic include illumination light sources and various display backlights. In particular, in recent years, it has become suitable to be used as a backlight for liquid crystal full-color displays where the demand has increased significantly.

  When the organic EL element is used as such an illumination light source or a display backlight, it is used as a light source whose emission color is white or a so-called light bulb color (hereinafter collectively referred to as white).

  In order to obtain white light emission, three light emitting layers of B (blue) / G (green) / R (red) are laminated, or light emission of two layers having a complementary color relationship such as B / Y (yellow). A method of stacking layers (for example, refer to Patent Document 1), a method of obtaining multicolored light emitting pixels, for example, blue, green, and red, separately, emitting light at the same time, and mixing them to obtain white, color conversion A method for obtaining a white color by using a dye (for example, a combination of a blue light-emitting dopant compound and a color-converting fluorescent dye), a method for preparing a plurality of light-emitting dopant compounds having different emission wavelengths in one element, and obtaining a white color by color mixing, etc. Thus, white light emission can be achieved by these methods.

  For the development of organic EL elements for practical application, M.M. A. Baldo et al. , Nature, 395, 151-154 (1998), since Princeton University reported on an organic EL device using phosphorescence emission from an excited triplet. A. Baldo et al. , Nature, 403, 17, 750-753 (2000), US Pat. No. 6,097,147, research on materials that exhibit phosphorescence at room temperature has become active.

  In addition, recently discovered organic EL devices that use phosphorescence can realize a luminous efficiency that is approximately four times that of previous devices that use fluorescence. Research and development of light-emitting element layer configurations and electrodes are performed all over the world.

  For example, S.M. Lamansky et al. , J .; Am. Chem. Soc. , 123, 4304 (2001), many synthetic studies have been conducted focusing on heavy metal complexes such as iridium complexes.

  As described above, the phosphorescence emission method is a method having a very high potential. However, an organic EL device using phosphorescence emission is greatly different from an organic EL device using fluorescence emission, and controls the position of the emission center. The method, particularly how to recombine within the light emitting layer and how to stably emit light, is an important technical issue in capturing the efficiency and lifetime of the device.

  Therefore, in recent years, a multi-layered element having a hole transport layer located on the anode side of the light emitting layer and an electron transport layer located on the cathode side of the light emitting layer in a form adjacent to the light emitting layer is well known. (For example, refer nonpatent literature 1.).

  In particular, when using blue phosphorescence, since the excited triplet energy of the blue phosphorescent material itself is large, development of peripheral materials and precise control of the emission center are strongly demanded.

  On the other hand, some of the photons emitted inside the organic EL element are actually reflected outside at the interface between the substrate and each organic functional layer or affected by plasmon absorption by the electrodes. It is known that there are photons that are not emitted, resulting in low luminous efficiency. As these light extraction technologies, optical properties between the substrate and the electrode, in particular, selection of the optimum organic layer thickness for each emission wavelength, reflection on the surface of the metal electrode, and high efficiency applying plasmon resonance are performed. In order to optimize these, it is necessary to freely change the thickness of the organic layer according to the light emitting material. However, even when using an organic material that is simply said to have good transportability, if the thickness is changed, the drive There have been problems that voltage drop, efficiency reduction, and life reduction occur.

  In order to solve these problems, there is an example of an n-type electron transport layer doped with an alkali metal compound by a co-evaporation method. For example, in Patent Document 2, an alkali metal compound is mixed with an electron transport material, and electron mobility is adjusted to optimize carrier balance, lower voltage, and higher luminous efficiency. However, in the case of mass production, the film deposition method by vapor deposition has a problem that the equipment cost increases with respect to the increase in area and continuous production of light emitting devices. In addition, when two or more materials are co-evaporated, it is difficult to precisely control the film formation rate, and there is a problem of lack of reliability. A light-emitting device can be formed by a simpler and more reliable film formation method. A way to create is desired.

  Due to these demands for large area, low cost, and high productivity, there is a great expectation for a wet process, and in particular, there is a strong demand for vacuum removal in electrode film formation. In addition, since film formation can be performed at a lower temperature than film formation in a vacuum process, damage to the underlying organic layer can be reduced, and there is great expectation in terms of improving light emission efficiency and device life. .

  As a method for forming an electron transport layer using a wet process, a method described in Patent Document 3 can be given. Patent Document 3 shows an example of an organic EL device in which a phosphine oxide derivative, which is an electron transport material that is soluble in an alcohol solvent and acts as a chelate ligand for a metal, is coated together with a metal complex. However, only examples using polymers are shown for the lower layer material, and it is sufficient for stacking on a layer formed of a low molecular compound that is indispensable for constructing a highly pure and durable device. It wasn't technical. Further, when combined with an electron transporting material having higher transportability, such an electron transporting material is mostly insoluble in alcohol, and there is a problem in the selection range of the material. In other words, it is insufficient to create a highly durable device that dissolves the electron-transporting alkali metal compound and the high-performance electron-transporting material at the same time, and does not dissolve the lower layer. Was needed.

JP 7-041759 A JP 2012-99962 A JP 2010-278376 A

Organic EL Handbook P-198, Realize Science Center, published in 2004

  Accordingly, the main object of the present invention is to provide an organic EL device that has excellent electron transportability, high light emission efficiency, low driving voltage, and long life even when an electron transport layer is formed by a wet process. In addition, another object is to provide a display device and a lighting device including the same.

〔式中、ｎは１又は２を表す。Ｒ１〜Ｒ６はそれぞれ独立に水素原子、ハロゲン原子、シアノ基、アルキル基、アルケニル基、アルキニル基、アルコキシ基、アミノ基、シリル基、アリールアルキル基、アリール基、ヘテロアリール基、非芳香族炭化水素環基又は非芳香族複素環基を表し、更に置換基を有していても良い。Ｒ１〜Ｒ６のうち何れか同士が結合して環を形成していても良い。Ｘは任意の異なっていても良い配位子を表し、ｍは０又は１以上の整数を表す。Ｍはリチウムを表す。〕 In order to achieve the above object of the present invention, according to one aspect of the present invention,
A pair of electrodes provided on the substrate, at least one light emitting layer disposed between the pair of electrodes, and an electron transport layer disposed between any one of the pair of electrodes and the light emitting layer In an organic electroluminescence device comprising:
The electron transport layer is
An electron transport compound, and quinolinato complexes of lithium, the coating liquid thus prepared is dissolved in a non-fluorinated alcohol solvent state, and are not formed by being dried is applied,
The lithium quinolinato complex is represented by the following general formula (1), and an organic electroluminescence device is provided.

[Wherein n represents 1 or 2. R1 to R6 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 hydrocarbon It represents a cyclic group or a non-aromatic heterocyclic group, and may further have a substituent. Any one of R1 to R6 may be bonded to form a ring. X represents an optionally different ligand, and m represents 0 or an integer of 1 or more. M represents lithium. ]

According to another aspect of the invention,
A display device comprising the organic electroluminescence element is provided.

According to still another aspect of the present invention,
An illumination device comprising the organic electroluminescence element is provided.

〔式中、ｎは１又は２を表す。Ｒ１〜Ｒ６はそれぞれ独立に水素原子、ハロゲン原子、シアノ基、アルキル基、アルケニル基、アルキニル基、アルコキシ基、アミノ基、シリル基、アリールアルキル基、アリール基、ヘテロアリール基、非芳香族炭化水素環基又は非芳香族複素環基を表し、更に置換基を有していても良い。Ｒ１〜Ｒ６のうち何れか同士が結合して環を形成していても良い。Ｘは任意の異なっていても良い配位子を表し、ｍは０又は１以上の整数を表す。Ｍはリチウムを表す。〕 According to still another aspect of the present invention,
A pair of electrodes provided on the substrate, at least one light emitting layer disposed between the pair of electrodes, and an electron transport layer disposed between any one of the pair of electrodes and the light emitting layer In a manufacturing method of an organic electroluminescence device comprising:
A step of preparing a coating solution by dissolving an electron transporting compound and a lithium quinolinate complex in a non-fluorinated alcohol solvent;
Forming the electron transport layer by applying and drying the coating solution ,
Provided is a method for producing an organic electroluminescent element, wherein the lithium quinolinato complex is represented by the following general formula (1) .

[Wherein n represents 1 or 2. R1 to R6 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 hydrocarbon It represents a cyclic group or a non-aromatic heterocyclic group, and may further have a substituent. Any one of R1 to R6 may be bonded to form a ring. X represents an optionally different ligand, and m represents 0 or an integer of 1 or more. M represents lithium. ]

According to the present invention, not only low voltage and long life can be achieved at low cost, but also light extraction design is facilitated, the external light emission quantum yield is improved, and high efficiency can be achieved.
Furthermore, by using a metal complex and an electron transporting material in combination, it is possible to suppress mass transfer in and between layers compared to the case of using a conventional metal salt of an electron injecting and transporting material, By using the mixed solvent, the residual solvent due to crystallization can be reduced, and a light-emitting device with high reliability with respect to thermal energy and high-temperature environment during element driving can be provided.

It is sectional drawing which shows schematic structure of the organic EL element of this invention.

Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail, but the present invention is not limited to these.
In the present invention, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

<< Configuration of organic EL element >>
As shown in FIG. 1, the organic EL element 100 is configured by sequentially laminating an anode 2, an organic compound layer (organic functional layer) laminate 20, and a cathode 8 on a support substrate 1.

The laminate 20 is composed of layers containing an organic compound, and includes a hole injection layer 3, a hole transport layer 4, a light emitting layer 5, an electron transport layer 6, and an electron injection layer 7.
In addition, an organic compound layer such as a hole blocking layer or an electron blocking layer may be provided.

  The anode 2, the laminate 20, and the cathode 8 are sealed with a sealing member 10 through a sealing adhesive 9.

  In addition, these layer structures (refer FIG. 1) of the organic EL element 100 show the preferable specific example, and this invention is not limited to these.

  For example, the organic EL element 100 may have the layer structure (i) or (ii).

(I) Anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode (ii) anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / Electron transport layer / electron injection layer / cathode

  In addition, these layer structures of the organic EL element 100 may have a tandem structure (multi-photon structure) in which an organic functional layer is repeatedly formed on the electron injection layer via a charge generation layer. In that case, the organic EL element should just form the white light emitting layer as the whole element, and may be comprised so that the repeating unit of an organic functional layer may light-emit with a separate luminescent color.

In the organic EL device of the present invention, the light emission maximum wavelength of the blue light emitting dopant compound is preferably in the range of 430 to 480 nm, and the green light emission dopant compound is in the range of the light emission maximum wavelength of 510 to 550 nm. Preferably has an emission maximum wavelength in the range of 600 to 640 nm, and is preferably an organic electroluminescence device using these. Moreover, the light emitting layer of at least three colors may be laminated to form a white light emitting layer, or a plurality of light emitting colors may be mixed in the same layer. Further, a non-light emitting intermediate layer may be provided between the light emitting layers.
In the case of forming a film by a coating method, a white layer obtained by mixing a light emitting dopant compound of three colors in a single layer is preferable from the viewpoint of cost and simplicity.
The organic EL element 100 of the present invention is preferably a white light emitting layer, and is preferably a lighting device using these.

  Each layer which comprises the organic EL element 100 of this invention is demonstrated.

<< Electron Transport Layer 6 >>
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 transmitting electrons to the light-emitting layer, any material can be selected from conventionally known compounds, such as nitro-substituted fluorene derivatives and 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 an oxygen atom of the oxadiazole ring is substituted with a sulfur atom, or 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.

In addition, metal complexes of 8-quinolinol derivatives, such as tris (8-quinolinol) aluminum (Alq) ₃ , 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 Metal complexes replaced with Cu, Ca, Sn, Ga, or Pb can also be used as electron transport materials. 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. Distyrylpyrazine derivatives can also be used as electron transport materials, and inorganic semiconductors such as n-type-Si and n-type-SiC can be used as electron-transport materials as well as hole-injection layers and hole-transport layers. Can do.

  The electron transport layer can be formed by dissolving the electron transport material in a solvent to prepare a coating solution, coating the coating solution, and drying. For example, there are known methods such as a spin coating method, a casting method, a printing method including an ink jet method, a spray method including an electrostatic spray method, and an LB method.

  Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, it exists in the range of 5 nm-5 micrometers, Preferably it exists in the range of 5-200 nm. The electron transport layer may have a single layer structure composed of one or more of the above materials.

Here, the electron transporting layer in the present invention comprises a coating solution prepared by dissolving an electron transporting compound and an alkali metal or alkaline earth metal quinolinate complex in a non-fluorinated alcohol solvent. Formed on the body and other organic functional layers, etc.) and dried.
The method for forming the electron transport layer in the present invention may be any method as long as the electron transport material can be fixed on the underlayer. The method of drying after the application to the underlayer is completed, and the coating liquid is applied to the underlayer. It includes any of the methods of applying and drying at the same time.

  Hereinafter, the composition of the coating solution used for forming the electron transport layer will be described.

(1) Alkali metal or alkaline earth metal quinolinate complex The alkali metal or alkaline earth metal quinolinate complex contained in the electron transport layer is preferably a compound represented by the general formula (1).

  In general formula (1), n represents 1 or 2. R1 to R6 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 hydrocarbon It represents a cyclic group or a non-aromatic heterocyclic group, and may further have a substituent. Any one of R1 to R6 may be bonded to form a ring. X represents an optionally different ligand, and m represents 0 or an integer of 1 or more. M represents an alkali metal or an alkaline earth metal.

  In the general formula (1), examples of the alkali metal or alkaline earth metal represented by M include lithium (Li), cesium (Cs), beryllium (Be), and magnesium (Mg), and lithium and cesium are electrons. Most preferable from the viewpoint of transportability.

  As the quinolinato complex represented by the general formula (1), 8-quinolinatolithium is most preferable in terms of production cost. Specifically, 8-hydroxyquinolinatolithium, 2-methyl-8-quinolinatolithium, 5 -Methyl-8-quinolinato lithium and the like.

(2) Electron transporting compound The electron transporting compound according to the present invention is an organic compound, and is preferably represented by the following general formula (2).
General formula (2)
Qm-Ln

  In General Formula (2), L represents a condensed aromatic heterocyclic ring, Q represents an aromatic hydrocarbon ring or an aromatic heterocyclic ring, and n and m each represent an integer of 1 to 3. When n is 2 or more, L may be different from each other, and when m is 2 or more, Q may be different from each other.

  Moreover, it is preferable that the compound represented by General formula (2) has at least 1 pyridine ring as a partial structure.

  The electron transporting compound according to the present invention is more preferably represented by any one of the following general formulas (4) to (100).

  In the general formulas (4) to (100), L and Q are synonymous with L and Q in the general formula (2).

In the general formula (2) and the general formulas (4) to (100), the condensed aromatic heterocycle represented by L is specifically an acridine ring, benzoquinoline ring, carbazole ring, phenazine ring, phenazine ring, Nanthridine ring, phenanthroline ring, carboline ring, cyclazine ring, quindrine ring, tepenidine ring, quinindrin ring, triphenodithiazine ring, triphenodioxazine ring, phenanthrazine ring, anthrazine ring, perimidine ring, diazacarbazole ring (carboline) Any one of the carbon atoms constituting the ring is replaced with a nitrogen atom), phenanthroline ring, dibenzofuran ring, dibenzothiophene ring, naphthofuran ring, naphthothiophene ring, benzodifuran ring, benzodithiophene ring, naphthodifuran ring, naphthofuran Dithiophene ring, anthra Examples include a lan ring, an anthradifuran ring, an anthrathiophene ring, an anthradithiophene ring, a thianthrene ring, a phenoxathiin ring, a thiophanthrene ring (naphthothiophene ring), etc., and in particular, a carbazole ring, a carboline ring, a dibenzofuran ring, A dibenzothiophene ring or the like is preferable.
Moreover, these rings may have the substituent mentioned later.

In the general formula (2) and the general formulas (4) to (100), the aromatic hydrocarbon ring represented by Q includes a benzene ring, a biphenyl ring, a naphthalene ring, an azulene ring, an anthracene ring, a phenanthrene ring, and a pyrene ring. , Chrysene ring, naphthacene ring, 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.
Furthermore, these rings may have a substituent described later.

In the general formula (2) and the general formulas (4) to (100), examples of the aromatic heterocycle represented by Q include a furan ring, a thiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, Pyrazine ring, triazine ring, benzimidazole ring, oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, indazole ring, benzimidazole ring, benzothiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring , Cinnoline ring, quinoline ring, isoquinoline ring, phthalazine ring, naphthyridine ring, carbazole ring, carboline ring, diazacarbazole ring (representing a ring in which one of the carbon atoms constituting the carboline ring is further substituted with a nitrogen atom), etc. Is mentioned.
Furthermore, these rings may have a substituent described later.

Here, L in the general formula (2) and the general formulas (4) to (100) preferably has a partial structure represented by the following general formula (3).

  In General Formula (3), A represents O, S, or N (R1), and A11 to A18 each represent a nitrogen atom or C (R2). R1 and R2 each represent a bond, a hydrogen atom or a substituent. However, when there are a plurality of C (R2), each C (R2) may be the same or different.

  In the general formula (3), N (R1) represented by A and C (R2) represented by each of A11 to A18 each represent a substituent represented by R1 and R2 as an alkyl group (for example, 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.), cycloalkyl group (for example, cyclopentyl group, cyclohexyl group) Etc.), an alkenyl group (for example, vinyl group, allyl group, 1-propenyl group, 2-butenyl group, 1,3-butadienyl group, 2-pentenyl group, isopropenyl group, etc.), alkynyl group (for example, ethynyl group, Propargyl group, etc.), aromatic hydrocarbon group (aromatic hydrocarbon ring group, aromatic carbocyclic group, aryl group, etc., for example, Phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, naphthyl group, anthryl group, azulenyl group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, etc.), aromatic heterocyclic group (for example, , Furyl group, thienyl group, pyridyl group, pyridazinyl group, pyrimidinyl group, pyrazinyl group, triazinyl group, imidazolyl group, pyrazolyl group, thiazolyl group, quinazolinyl group, carbazolyl group, carbolinyl group, diazacarbazolyl group (said carbolinyl group) Any one of the carbon atoms constituting the carboline ring is substituted with a nitrogen atom), a phthalazinyl group, etc.), a heterocyclic group (eg, a pyrrolidyl group, an imidazolidyl group, a morpholyl group, an oxazolidyl group, etc.), an alkoxy group (For example, methoxy group, Xy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.), cycloalkoxy group (for example, cyclopentyloxy group, cyclohexyloxy group, etc.), 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.), cycloalkylthio group (eg, cyclopentylthio group, cyclohexylthio group, etc.), Arylthio group (eg, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxy group) Xycarbonyl group, etc.), aryloxycarbonyl group (eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (eg, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexyl) Aminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), acyl group (for example, acetyl group, ethylcarbonyl group, propyl group) Carbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbo Group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (eg, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide Groups (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group) , Phenylcarbonylamino group, naphthylcarbonylamino group, etc.), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylamino group) Bonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group 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, dodecylsulfuric group Finyl 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.), arylsulfonyl 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, etc.), Fluorinated hydrocarbon groups (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, trimethyl group) Isopropylsilyl group, triphenylsilyl group, phenyldiethylsilyl group, etc.) and phosphono group.

  These substituents may be further substituted with the above substituents. In addition, a plurality of these substituents may be bonded to each other to form a ring.

  Hereinafter, although the specific example of the compound preferably used as an electron transport compound concerning the present invention is shown, the present invention is not limited to these.

  The electron transporting compound according to the present invention is disclosed in JP 2007-288035 A, Chem. Mater. It can be synthesized by referring to known methods described in 2008, 20, 5951, Experimental Chemistry Course 5th Edition (Edited by Chemical Society of Japan).

These single compounds may be used as the electron transporting compound according to the present invention, but two or more compounds including the above-mentioned general electron transporting material can be used in combination.
In that case, in addition to the electron transporting compound, an alkali metal or alkaline earth metal compound other than lithium is preferably contained, more preferably sodium (Na), potassium (K), cesium (Cs The metal compound of cesium is most preferable from the viewpoint of electron injection and material stability. Specific examples include sodium fluoride, potassium fluoride, cesium fluoride, sodium acetate, cesium acetate and the like.

(3) Non-fluorinated alcohol solvent As a solvent for preparing the coating solution by dissolving the alkali metal or alkaline earth metal quinolinate complex and the electron transporting compound, the viewpoint of ensuring the solubility of the quinolinato complex. A non-fluorinated alcohol solvent is used.
Furthermore, it is preferable to mix and use a fluorinated alcohol solvent in a non-fluorinated alcohol solvent from the viewpoint of the solubility of the electron transport compound and the lower layer dissolution suppression. By doing so, these materials having different solubilities can be easily dissolved in one solution, so that a coating solution can be easily prepared, and a highly durable element can be obtained without dissolving the underlayer. It can be easily produced by a single film formation.

In the present invention, the non-fluorinated alcohol solvent means an alcohol solvent containing no fluorine atom in the molecule.
Examples of the non-fluorinated alcohol solvent used in the present invention include methanol, ethanol, n-propanol, isopropanol, n-butanol, iso-butanol, tert-butanol, etc., and lower alcohols are preferable from the viewpoint of drying properties. .

In the present invention, the fluorinated alcohol solvent means a solvent in which at least one hydrogen atom in the molecule of the alcohol solvent is replaced with a fluorine atom.
Examples of the fluorinated alcohol solvent used in the present invention include trifluoroethanol (TFEO), tetrafluoropropanol (TFPO), and hexafluoropropanol (HFPO). The position of the fluorine atom in the molecule in these fluorinated alcohol solvents is not particularly limited, but 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoropropanol, 1,1,1,3,3 , 3-hexafluoropropan-2-ol is preferred.

(4) Other additives In addition to the above-described alkali metal or alkaline earth metal quinolinate complex, electron transporting compound, fluorinated alcohol solvent and non-fluorinated alcohol solvent, the coating liquid used for forming the electron transport layer In addition, for the purpose of adjusting the viscosity and vapor pressure of the coating solution, additives such as other types of solvents and surfactants may be contained.

<< Injection layer: hole injection layer 3, electron injection layer 7 >>
The injection layer has an electron injection layer (cathode buffer layer) and a hole injection layer (anode buffer layer). As described above, the hole injection layer is an electron injection between the anode and the light emitting layer or the hole transport layer. The layer can be provided between the cathode and the light emitting layer or the electron transport layer.

  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) ) ", Chapter 2, Chapter 2," Electrode Materials "(pp. 123-166).

  The details of the hole injection layer (anode buffer layer) are described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069 and the like. As a specific example, polyaniline (emeral) Din) and a polymer buffer layer using a conductive polymer such as polythiophene.

  The details of the electron injection layer (cathode buffer layer) are also 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. Especially preferably, it exists in the range of 20-100 nm.

<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, they are described in JP-A Nos. 11-204258 and 11-204359, and “Organic EL elements and their forefront of industrialization” (issued by NTT Corporation 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 a carbazole derivative, a carboline derivative or a diazacarbazole derivative, which will be mentioned as a host compound described later.

  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 in the range of 3 to 100 nm, and more preferably in the range of 5 to 30 nm.

<< Hole Transport Layer 4 >>
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.

  As the hole transporting material constituting the hole transporting layer, the same compounds as those applied in the hole injecting layer can be used, and further, porphyrin compounds, aromatic tertiary amine compounds and styryl. It is preferable to use an amine 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 ' Di (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadriphenyl N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenylamino -(2-diphenylvinyl) benzene; 3-methoxy-4'-N, N-diphenylaminostilbenzene; N-phenylcarbazole, as well as those described in US Pat. No. 5,061,569 Having four condensed aromatic rings in the molecule, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 08688 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-4-297076, JP-A-2000-196140, JP-A-2001-102175, J. Pat. Appl. Phys. , 95, 5773 (2004), JP-A-11-251067, J. MoI. Huang et. al. It is also possible to use a hole transport material that has a so-called p-type semiconducting property as described in the literature (Applied Physics Letters 80 (2002), p. 139), JP 2003-519432 A. it can.

  The hole transport layer is 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. Can do. The thickness of the hole transport layer is not particularly limited, but is usually about 5 nm to 5 μm, preferably 5 to 200 nm. The hole transport layer may have a single layer structure composed of one or more of the above materials.

  Hereinafter, specific examples of the polymer compound preferably used for the hole transporting material will be exemplified. However, it is not limited to these.

  In addition, n described in the above exemplary compounds represents the degree of polymerization and represents an integer having a weight average molecular weight in the range of 50,000 to 200,000. If the weight average molecular weight is less than this range, there is a concern of mixing with other layers during film formation due to high solubility in a solvent. Even if a film can be formed, the light emission efficiency does not increase at a low molecular weight. When the weight average molecular weight is larger than this range, problems arise due to difficulty in synthesis and purification. Since the molecular weight distribution increases and the residual amount of impurities also increases, the light emission efficiency, voltage, and life of the organic EL element deteriorate.

  In addition to the above hole transporting compound, the hole transporting layer may contain various light emitting materials, electron transporting compounds, binder resins, coating property improving agents such as surfactants, and the like.

Further, it may be a layer containing a crosslinkable compound that has a crosslinkable group and forms a network polymer compound by crosslinking after coating film formation.
Examples of the crosslinkable group include cyclic ether groups such as epoxy and oxetane, unsaturated double bond groups such as vinyl group, trifluorovinyl group, styryl group, acrylic group, methacryloyl and cinnamoyl, and benzocyclobutene group.
The crosslinkable compound may be any of a monomer, an oligomer, and a polymer, and may have two or more kinds in any combination ratio. Moreover, the additive which accelerates | stimulates a crosslinking reaction may be included.
As the crosslinkable compound, a hole transporting compound having a crosslinkable group is preferably used. Hole transporting compounds include, for example, nitrogen-containing aromatic compound derivatives such as pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, phenanthroline derivatives, carbazole derivatives, phthalocyanine derivatives, porphyrin derivatives, triphenylamine derivatives, siloles. Derivatives, oligothiophene derivatives, condensed polycyclic aromatic derivatives, metal complexes and the like.
Hereinafter, specific compounds of the crosslinkable compound preferably used for the hole transport material are exemplified. However, it is not limited to these.

The crosslinkable compound can be formed by thinning the film by a known wet film forming method such as a spin coating method, a casting method, a printing method including an ink jet method, or an LB method.
After forming a hole transport layer containing a crosslinkable compound on a lower layer (usually a hole injection layer), the hole transport layer is formed by crosslinking the crosslinkable compound by irradiation with heat energy or electromagnetic energy such as light. . These energy provisions may be cross-linked by combining two or more methods.

  These polymer compounds are disclosed in Makromol. Chem. , Pages 193, 909 (1992) and the like.

<Light emitting layer 5>
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 or the electron transport layer and 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 total film thickness of the light emitting layer is not particularly limited, but from the viewpoint of improving the uniformity of the film, preventing unnecessary application of high voltage during light emission, and improving the stability of the emission color with respect to the drive current. It is preferable to adjust in the range of 2 nm to 5 μm, more preferably in the range of 2 to 200 nm, and particularly preferably in the range of 10 to 100 nm.

  The light emitting layer of the organic EL device of the present invention contains a light emitting dopant (such as a phosphorescent light emitting dopant or a fluorescent light emitting dopant) compound and a host compound.

(1) Luminescent dopant compound As the luminescent dopant compound according to the present invention, a fluorescent luminescent dopant compound or a phosphorescent luminescent dopant compound (also referred to as a phosphorescent compound or a phosphorescent luminescent compound) can be used. A photoluminescent dopant compound is preferred.

(1.1) Phosphorescent light emitting dopant compound As the light emitting dopant compound, a phosphorescent light emitting dopant compound (also referred to as a phosphorescent compound) is preferable because high luminous efficiency is obtained. The phosphorescent dopant compound is a compound in which light emission from an excited triplet is observed, and is a compound having a phosphorescence quantum yield of 0.01 or more at 25 ° C. Preferably it is 0.1 or more. In the present invention, any other compound contained in the light emitting layer is used as the host compound.

  In addition, the ratio of the host compound and the phosphorescent dopant compound in the light emitting layer is 1 to 99% by mass for each compound, assuming that the mass of the compound contained in the entire light emitting layer is 100%. However, the ratio of the host compound is preferably larger than that of the phosphorescent dopant compound, and the ratio of the phosphorescent dopant compound is more preferably 1 to 30% by mass.

  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 emitting dopant compound used in the present invention is a compound that achieves the phosphorescence quantum yield in any solvent. is there.

  There are two types of emission principles of the phosphorescent dopant compound. One is the recombination of carriers on the host compound to which carriers are transported to generate an excited state of the 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 compound is obtained by transferring to a compound. The other is a carrier trap type in which a phosphorescent dopant compound becomes a carrier trap, and recombination of carriers occurs on the phosphorescent dopant compound, 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 compound is lower than the excited state energy of the host compound.

  The phosphorescent dopant compound can be appropriately selected from known compounds used for the light-emitting layer of the organic EL device, but preferably a complex system containing a metal of group 8 to 10 in the periodic table of elements. Compounds, more preferably iridium compounds, osmium compounds, platinum compounds (platinum complex compounds), rare earth complexes, and most preferred are iridium compounds.

  The phosphorescent dopant compound according to the present embodiment includes at least one blue phosphorescent material, and preferably has at least one blue phosphorescent material and a band gap energy lower than that of the blue phosphorescent material. And at least two phosphorescent materials.

Below, the phosphorescence dopant compound which can be used as a material of a light emitting layer in this invention is demonstrated.
The phosphorescent dopant that can be used in the present invention is preferably represented by the following general formula (B).

  In general formula (B), ring Am, ring An, ring Bm and ring Bn represent a 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocycle, and Ar represents an aromatic hydrocarbon ring or aromatic heterocycle. Represents a non-aromatic hydrocarbon ring or a non-aromatic heterocyclic ring. R1m, R2m, R1n and R2n each independently represents an alkyl group having 2 or more carbon atoms, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group; It may have a substituent. 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 It represents a hydrocarbon ring group or a non-aromatic heterocyclic group, may further have a substituent, and Ra may form a ring with Ar. na and nc represent 1 or 2, and nb represents an integer of 1 to 4. m represents 1 or 2, n represents 1 or 2, and m + n is 3. Note that the structures of the three ligands coordinated to Ir are not all the same.

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

In the general formula (B), 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 (B), 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 Rings substituted with nitrogen atom, benzodifuran ring, benzodithiophene ring, acridine ring, benzoquinoline ring, phenazine ring, phenanthridine ring, phenanthroline ring, cyclazine ring, kindrin ring, tepenidine ring, quinindrine 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 (B), examples of the non-aromatic hydrocarbon ring represented by Ar include cycloalkane (for example, cyclopentane ring, cyclohexane ring, etc.), cycloalkoxy group (for example, cyclopentyloxy group, cyclohexyloxy group). Etc.), cycloalkylthio group (for example, cyclopentylthio group, cyclohexylthio group, etc.), cyclohexylaminosulfonyl group, tetrahydronaphthalene ring, 9,10-dihydroanthracene ring, biphenylene ring and the like.
In the general formula (B), examples of the non-aromatic heterocyclic ring 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 Examples include enoxazine ring, phenothiazine ring, oxanthrene ring, thioxanthene ring, phenoxathiin ring and the like.

  In the general formula (B), these rings represented by Ar may have a substituent, and the substituents may be bonded to each other to form a ring.

  In the general formula (B), Ar is preferably 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 (B), examples of the alkyl group represented by R1m and R2m include a methyl group, an ethyl group, a trifluoromethyl group, an isopropyl group, an n-butyl group, a t-butyl group, an n-hexyl group, Examples include 2-methylhexyl group, pentyl group, adamantyl group, n-decyl group, n-dodecyl group and the like.
In the general formula (B), the aromatic hydrocarbon ring group, aromatic heterocyclic group, non-aromatic hydrocarbon ring group or non-aromatic heterocyclic group represented by R1m and R2m is the above-described general formula (B ), A monovalent group derived from an aromatic hydrocarbon ring, an aromatic heterocyclic ring, a non-aromatic hydrocarbon ring or a non-aromatic heterocyclic ring represented by Ar.
In the general formula (B), an alkyl group having 2 or more carbon atoms, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group represented by R1m and R2m Further, examples of the substituent which may be present include 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 heteroaryl group, a non-aryl group, An aromatic hydrocarbon ring group, a non-aromatic heterocyclic group, etc. are mentioned.
In general formula (B), R1m and R2m are preferably both an alkyl group or a cycloalkyl group having 2 or more carbon atoms, and either one of R1m and R2m is a branched alkyl group having 3 or more carbon atoms. It is also preferable. More preferably, both R1m and R2m are branched alkyl groups having 3 or more carbon atoms.

  In general formula (B), R1n and R2n have the same meanings as R1m and R2m in general formula (B).

In the general formula (B), 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 (B). And a monovalent group.
In the general formula (B), 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 (B) And monovalent groups derived from a hydrogen ring and a non-aromatic heterocyclic ring.

  The iridium complex compound represented by the general formula (B) is preferably represented by the following general formula (C).

  In general formula (C), Ar represents an aromatic hydrocarbon ring, an aromatic heterocyclic ring, a non-aromatic hydrocarbon ring or a non-aromatic heterocyclic ring. R1m, R2m, R1n and R2n each independently represents an alkyl group having 2 or more carbon atoms, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group; It may have a substituent. Ra 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 hydrocarbon Represents a cyclic group or a non-aromatic heterocyclic group, may further have a substituent, and Ra may form a ring with Ar. na and nc represent 1 or 2. m represents 1 or 2, n represents 1 or 2, and m + n is 3. Note that the structures of the three ligands coordinated to Ir are not all the same.

  In the general formula (C), Ar, R1m, R2m, R1n, R2n, Ra, Rc, na, nc, m, and n are Ar, R1m, R2m, R1n, R2n, Ra, Rc, It is synonymous with na, nc, m and n.

  The iridium complex compounds represented by the general formulas (B) and (C) preferably used in the present invention can be synthesized by referring to known methods described in International Publication No. 2006/121811, etc. .

  The iridium complex compound represented by the general formula (C) is preferably represented by the following general formula (D).

In general formula (D), R1m, R2m, R1n and R2n are each independently an alkyl group having 2 or more carbon atoms, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic group. It represents a heterocyclic group and may further have a substituent. Ra, Rc and Ra ₃ 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 nR3 represents an integer of 1 to 5. m represents 1 or 2, n represents 1 or 2, and m + n is 3. Note that the structures of the three ligands coordinated to Ir are not all the same.

In the general formula (D), R1m, R2m, R1n, R2n, Ra, Rc, na, nc, m, and n are R1m, R2m, R1n, R2n, Ra, Rc, na, nc, general formula (B). It is synonymous with m and n.
In the general formula (D), Ra ₃ has the same meaning as Ra, Rb and Rc in the general formula (B).

  The iridium complex compound represented by the general formula (B) is preferably represented by the following general formula (E).

In general formula (E), R1m, R2m, R1n and R2n are each independently an alkyl group having 2 or more carbon atoms, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic group. It represents a heterocyclic group and may further have a substituent. Ra, Rc and Ra ₃ 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 nR3 represents an integer of 1 to 4. X represents O, S, SiRz1Rz2, NRz1 or CRz1Rz2, and Rz1 and Rz2 each represents an alkyl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group, or a non-aromatic heterocyclic group. . m represents 1 or 2, n represents 1 or 2, and m + n is 3.

In the general formula (E), R1m, R2m, R1n, R2n, Ra, Rc, na, nc, m, and n are R1m, R2m, R1n, R2n, Ra, Rc, na, nc, in the general formula (B). It is synonymous with m and n.
In formula (E), Ra ₃ have the same meanings as Ra, Rb and Rc in formula (B).

  In X in the general formula (E), the aromatic hydrocarbon ring group, the aromatic heterocyclic group, the non-aromatic hydrocarbon ring group, or the non-aromatic heterocyclic group represented by Rz1 and Rz2 is the above general formula ( Examples thereof include a monovalent group derived from an aromatic hydrocarbon ring, aromatic heterocycle, non-aromatic hydrocarbon ring or non-aromatic hydrocarbon ring represented by Ar in B).

  The iridium complex compound represented by the general formula (B) is preferably represented by the following general formula (F).

In general formula (F), R1m, R2m, R1n and R2n are each independently an alkyl group having 2 or more carbon atoms, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic group. It represents a heterocyclic group and may further have a substituent. Ra, Rc and Ra ₃ 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 nR3 represents an integer of 1 to 4. X represents O, S, SiRz1Rz2, NRz1 or CRz1Rz2, and Rz1 and Rz2 each represents an alkyl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group, or a non-aromatic heterocyclic group. . m represents 1 or 2, n represents 1 or 2, and m + n is 3.

In the general formula (F), R1m, R2m, R1n, R2n, Ra, Rc, na, nc, m, and n are R1m, R2m, R1n, R2n, Ra, Rc, na, nc, general formula (B). It is synonymous with m and n.
In formula (F), Ra ₃ have the same meanings as Ra, Rb and Rc in formula (B).
In general formula (F), X is synonymous with X in general formula (E).

  Below, the specific compound of the phosphorescence emission dopant compound which can be used by this invention is illustrated. However, the present invention is not limited to these.

(1.2) Combined use with conventionally known dopants In addition, the light-emitting dopant according to the present invention may be used in combination of a plurality of types of compounds, a combination of phosphorescent dopants having different structures, a phosphorescent dopant and A combination of fluorescent dopants may also be used.

  Here, although the specific example of the conventionally well-known light emission dopant which may be used together with the iridium complex compound represented by General formula (1) concerning this invention as a light emission dopant is given, this invention is not limited to these. .

(2) Host compound (2.1) Host compound represented by general formula (A) The host compound that can be used in the present invention is preferably represented by the following general formula (A).

  In the general formula (A), X represents NR ′, O, S, CR′R ″ or SiR′R ″. R ′ and R ″ each represent a hydrogen atom or a substituent. Ar represents an aromatic ring. N represents an integer of 0 to 8.

  In the general formula (A), each of the substituents represented by R ′ and R ″ in CR′R ″ or SiR′R ″ represented by X is an alkyl group (for example, methyl group, ethyl group, propyl group). Group, isopropyl group, t-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, etc.), cycloalkyl group (for example, cyclopentyl group, cyclohexyl group etc.), alkenyl group ( For example, vinyl group, allyl group, etc.), alkynyl group (for example, ethynyl group, propargyl group, etc.), aromatic hydrocarbon ring group (aromatic carbocyclic group, aryl group, etc.), for example, phenyl group, p-chlorophenyl Group, mesityl group, tolyl group, xylyl group, naphthyl group, anthryl group, azulenyl group, acenaphthenyl group, fluorene group Group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group, etc.), aromatic heterocyclic group (for example, pyridyl group, pyrimidinyl group, furyl group, pyrrolyl group, imidazolyl group, benzimidazolyl group, pyrazolyl group, pyrazinyl group, triazolyl group) Groups (for example, 1,2,4-triazol-1-yl group, 1,2,3-triazol-1-yl group, etc.), oxazolyl group, benzoxazolyl group, thiazolyl group, isoxazolyl group, isothiazolyl group, Flazanyl group, thienyl group, quinolyl group, benzofuryl group, dibenzofuryl group, benzothienyl group, dibenzothienyl group, indolyl group, carbazolyl group, carbolinyl group, diazacarbazolyl group (carbon atoms constituting the carboline ring of carbolinyl group) One of which was replaced by a nitrogen atom Quinoxalinyl group, pyridazinyl group, triazinyl group, quinazolinyl group, phthalazinyl group, etc.), heterocyclic group (eg, pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group, etc.), alkoxy group (eg, methoxy group, ethoxy group) Group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.), cycloalkoxy group (for example, cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (for example, phenoxy group, naphthyl group, etc.) Oxy group etc.), alkylthio group (eg methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group etc.), cycloalkylthio group (eg cyclopentylthio group, Chlorothio group, etc.), arylthio group (eg, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group) Etc.), aryloxycarbonyl group (eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (eg, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group) Cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyri Acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthyl, etc. Carbonyl group, pyridylcarbonyl group, etc.), acyloxy group (eg, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide group (eg, Methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group Group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino 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 group, etc.) Ureido group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecyl group) Ureido group, phenylureido group, naphthylureido group, 2-pyridylaminoureido group, etc.), sulfinyl group (for example, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenyl) Sulfinyl 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 A sulfonyl group or a heteroarylsulfonyl group (eg, phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino (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, etc.), fluorinated hydrocarbon group (for example, fluoromethyl group, trifluoromethyl group, pentafluoroethyl group, pentafluorophenyl group, etc.), cyano group, nitro group, hydroxy group, Examples include a mercapto group and a silyl group (for example, a trimethylsilyl group, a triisopropylsilyl group, a triphenylsilyl group, a phenyldiethylsilyl group, etc.). These substituents may be further substituted with the above substituents. A plurality of these substituents may be bonded to each other to form a ring.

Among these, X is preferably NR ′ or O, and R ′ is an aromatic hydrocarbon group (also referred to as an aromatic carbocyclic group, an aryl group, etc., for example, a phenyl group, a p-chlorophenyl group, a mesityl group, A tolyl group, a xylyl group, a naphthyl group, an anthryl group, an azulenyl group, an acenaphthenyl group, a fluorenyl group, a phenanthryl group, an indenyl group, a pyrenyl group, a biphenylyl group), or an aromatic heterocyclic group (for example, a furyl group, a thienyl group, a pyridyl group) Group, pyridazinyl group, pyrimidinyl group, pyrazinyl group, triazinyl group, imidazolyl group, pyrazolyl group, thiazolyl group, quinazolinyl group, phthalazinyl group and the like are particularly preferable.
The above aromatic hydrocarbon group and aromatic heterocyclic group each may have a substituent represented by R ′ or R ″ in the general formula (A).

  In the general formula (A), examples of the aromatic ring represented by Ar include an aromatic hydrocarbon ring and an aromatic heterocyclic ring. The aromatic ring may be a single ring or a condensed ring, and may be unsubstituted, or may have a substituent represented by R ′ or R ″ in the general formula (A). Good.

  In the general formula (A), 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. These rings may further have substituents represented by R ′ and R ″ in the general formula (A).

In the general formula (A), examples of the aromatic heterocycle represented by Ar include a furan ring, a dibenzofuran 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. , Benzimidazole ring, oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indazole ring, indazole ring, benzimidazole ring, benzothiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, cinnoline ring, quinoline Ring, isoquinoline ring, phthalazine ring, naphthyridine ring, carbazole ring, carboline ring, diazacarbazole ring (showing a ring in which one of the carbon atoms of the hydrocarbon ring constituting the carboline ring is further substituted with a nitrogen atom), etc. Can be mentioned.
These rings may further have substituents represented by R ′ and R ″ in the general formula (A).

  Among the above, in the general formula (A), the aromatic ring represented by Ar is preferably a carbazole ring, carboline ring, dibenzofuran ring, or benzene ring, and more preferably a carbazole ring, carboline ring, or benzene ring. More preferred is a benzene ring having a substituent, and particularly preferred is a benzene ring having a carbazolyl group.

  In the general formula (A), each of the aromatic rings represented by Ar is preferably a condensed ring having 3 or more rings, and the aromatic hydrocarbon condensed ring in which 3 or more rings are condensed is a specific example. Naphthacene ring, anthracene ring, tetracene ring, pentacene ring, hexacene ring, phenanthrene ring, pyrene ring, benzopyrene ring, benzoazulene ring, chrysene ring, benzochrysene ring, acenaphthene ring, acenaphthylene ring, triphenylene ring, coronene ring, benzocoronene Ring, hexabenzocoronene ring, fluorene ring, benzofluorene ring, fluoranthene ring, perylene ring, naphthoperylene ring, pentabenzoperylene ring, benzoperylene ring, pentaphen ring, picene ring, pyrantolen ring, coronene ring, naphthocolonene ring, ovalen ring, Anthracanthrene rings It is. These rings may further have the above substituents.

  Specific examples of the aromatic heterocycle condensed with three or more rings include an acridine ring, a benzoquinoline ring, a carbazole ring, a carboline ring, a phenazine ring, a phenanthridine ring, a phenanthroline ring, a carboline ring, a cyclazine ring, Kindin ring, tepenidine ring, quinindrin ring, triphenodithiazine ring, triphenodioxazine ring, phenanthrazine ring, anthrazine ring, perimidine ring, diazacarbazole ring (any one of the carbon atoms constituting the carboline ring is a nitrogen atom Phenanthroline ring, dibenzofuran ring, dibenzothiophene ring, naphthofuran ring, naphthothiophene ring, benzodifuran ring, benzodithiophene ring, naphthodifuran ring, naphthodithiophene ring, anthrafuran ring, anthradifuran ring , Emissions tiger thiophene ring, anthradithiophene ring, thianthrene ring, phenoxathiin ring, such as thio fan train ring (naphthothiophene ring). In addition, these rings may further have a substituent.

  Moreover, in general formula (A), although n represents the integer of 0-8, it is preferable that it is 0-2, and when X is O and S especially, it is preferable that it is 1-2.

  In the present invention, a low molecular compound having both a dibenzofuran ring and a carbazole ring is particularly preferable.

  Specific examples of host compounds that can be used in the present invention are shown below. However, the present invention is not limited to these.

(2.2) Combined use with conventionally known host compounds The host compound according to the present invention may be used in combination of a plurality of types of compounds. By using a plurality of types of host compounds, the mobility (movement amount) of electric charges (holes and / or electrons) can be adjusted, and the light emission efficiency of the organic EL element 100 can be improved.

  As the host compound that may be used in combination with the host compound represented by the general formula (A), a known host compound can be used.

  In this invention, there is no restriction | limiting in particular as a host compound which can be used together, The compound conventionally used with an organic EL element can be used. Typically, a carbazole derivative, a triarylamine derivative, an aromatic derivative, a nitrogen-containing heterocyclic compound, a thiophene derivative, a furan derivative, an oligoarylene compound or the like having a basic skeleton, or a carboline derivative or a diazacarbazole derivative (here And the diazacarbazole derivative represents one in which at least one carbon atom of the hydrocarbon ring constituting the carboline ring of the carboline derivative is substituted with a nitrogen atom.

  As the known host compound that can be used in the present invention, a compound that has a hole transporting ability and an electron transporting ability, prevents the emission of light from being increased in wavelength, and has a high Tg (glass transition temperature) is preferable.

  In addition, by using three or more known compounds used as phosphorescent light emitting dopants, a white luminescent color with good color rendering can be obtained.

  The host compound used in the present invention may be a low molecular compound, 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 (polymerizable light emitting host). Of course, two or more such compounds may be used.

  Specifically, the host compound preferably has a carbazole skeleton, a triarylamine skeleton, a thiophene skeleton, a furan skeleton, a carboline skeleton, or a diazacarbazole skeleton, and has a carbazole skeleton, a thiophene skeleton, or a furan skeleton. Is more preferable.

  Specific examples of known host compounds include compounds described in the following documents.

  JP-A-2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579, 2002-105445 gazette, 2002-343568 gazette, 2002-141173 gazette, 2002-352957 gazette, 2002-203683 gazette, 2002-363227 gazette, 2002-231453 gazette, No. 003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-286061, No. 2002-280183, No. 2002-299060, No. 2002. -302516, 2002-305083, 2002-305084, 2002-308837, and the like.

The light emitting layer preferably contains a low molecular weight compound, and is preferably a low molecular weight compound not containing a repeating unit having a molecular weight of 3000 or less from the viewpoint of the ease of material synthesis and the solvent content during film formation. More preferably, it is the range of 200-2000, More preferably, it is the range of 400-1500. When the molecular weight is greater than 3000, not only the material synthesis is complicated and the production cost increases, but also the solvent is easily taken into the voids between the molecules and the light emission becomes unstable, and the light emission is caused by the heat generated during driving and the temperature during storage. Reliability is impaired.
“Molecular weight” as used herein is obtained using a conventionally known mass spectrum. For polymers (for example, those having a molecular weight of 10,000 or more), a conventionally known GPC (gel permeation chromatography) is used. It is measured.

(3) Wet Process The light emitting layer according to the present invention is a layer containing a light emitting dopant compound uniformly by being formed by a wet process. In the present invention, the wet process is preferably film formation by a coating method such as a spin coating method, an ink jet method, a printing method, or a spray coating method.
The electron transport layer of the present invention is formed by a wet process.

  Examples of the liquid medium for dissolving or dispersing the organic EL device material according to the present invention include ketones such as methyl ethyl ketone and cyclohexanone, and fatty acid esters such as ethyl acetate, isopropyl acetate, propylene glycol monomethyl ether acetate, and 3-methoxybutyl acetate. , Halogenated hydrocarbons such as dichlorobenzene, aromatic hydrocarbons such as toluene, xylene, mesitylene and cyclohexylbenzene, non-fluorinated alcohols such as methanol, ethanol, propanol and isopropanol, trifluoroethanol (TFEO), tetra Fluorinated alcohols such as fluoropropanol (TFPO) and hexafluoropropanol (HFPO), aliphatic hydrocarbons such as cyclohexane, decalin and dodecane, DMF, DMSO, etc. Although it is possible to use an organic solvent, from the viewpoint of inhibiting a solvent amount contained in the device, the boiling point is preferably used is a solvent in the range of 50 ° C. to 180 ° C.. 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.

In the present invention, the solvent content contained in the organic EL element is in the range of 1 to 0.01 μg / cm ² . In the case of 0.01 μg or less, the organic film becomes sparse, so that a high voltage is generated when the element is driven. In the case of 1 μg / cm ² or more, substance diffusion or aggregation of the light emitting material is caused when the element is driven. Efficiency, low drive life. These solvent contents can be determined by temperature programmed desorption gas spectroscopy.

<< Anode 2 >>
As the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound and 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.

  The anode may be formed by depositing a thin film of these electrode materials by vapor deposition or sputtering, and a pattern having a desired shape may be formed by photolithography, 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 in the range of 10 to 1000 nm, preferably in the range of 10 to 200 nm.

<< Cathode 8 >>
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 the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected within the range of 10 nm to 5 μm, preferably within the range of 50 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 with the film thickness in the range of 1-20 nm in a cathode, producing a transparent or semi-transparent cathode 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.

<Supporting substrate 1>
The 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 is not particularly limited in the type of glass, plastic, etc., and is transparent. Or 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, polysulfone , Polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic or polyarylates, cyclone resins such as Arton (trade name, manufactured by JSR) or Appel (trade name, manufactured by Mitsui Chemicals) Etc.

On the surface of the resin film, an inorganic film, an organic film, or a hybrid film of both may be formed. Water vapor permeability (25 ± 0.5 ° C.) measured by a method according to JIS K 7129-1992. , Relative humidity (90 ± 2)% RH) is preferably 0.01 g / (m ² · 24 h) or less, and further, oxygen measured by a method according to JIS K 7126-1987. A high barrier film having a permeability of 10 ⁻³ cm ³ / (m ² · 24 h · atm) or less and a water vapor permeability of 10 ⁻³ g / (m ² · 24 h) or less is preferable. More preferably, the transmittance is 10 ⁻⁵ g / (m ² · 24 h) or less.

  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, ceramic substrates, and the like.

<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 has an oxygen permeability measured by a method according to JIS K 7126-1987 of 1 × 10 ⁻³ cm ³ / (m ² · 24 h · atm) or less, and conforms to JIS K 7129-1992. The water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) measured by the above method is preferably 1 × 10 ⁻³ g / (m ² · 24 h) 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 liquid 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. Further, 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 infiltration 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 method, sputtering method, reactive sputtering method, molecular beam epitaxy method, 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 (eg, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide), sulfates (eg, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate). Etc.), metal halides (for example, calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide, etc.), perchloric acids (for example, perchloric acid) Barium, magnesium perchlorate, etc.), 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 or the sealing film on the side facing the support substrate with the organic layer interposed therebetween. In particular, when sealing is performed with a 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, etc. used for sealing can be used. It is preferable to use it.

《Light extraction》
The organic EL element emits light inside a layer having a refractive index higher than that of air (with a refractive index in the range of 1.7 to 2.1), and light of about 15% to 20% of the light generated in the light emitting layer. It is generally said that it can only be taken out. 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 in the range of 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. Of these, light that cannot go out due to total reflection between layers, etc. is diffracted by introducing a diffraction grating into any layer or medium (inside a transparent substrate or transparent electrode). 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 one of the layers or in the medium (in the transparent substrate or 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 in the range of 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 element of the present invention is processed on the light extraction side of the substrate, for example, to provide a microlens array-like structure, or in combination with a so-called condensing sheet, for example, with respect to a specific direction, for example, the element 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 within a range of 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 with 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 >>
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 by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably in the range of 10 to 200 nm. Make it.

  Next, an organic compound thin film of a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection 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, printing method, spray method) and the like. In the present invention, the electron transport layer is an alkali metal or alkaline earth. It is formed by a wet process using a quinolinate complex of a similar metal and an electron transporting compound.
Also, other organic functional layers are preferably formed by a wet process from the viewpoint that a uniform film is easily obtained, the materials can be mixed at an arbitrary ratio, and pinholes are not easily generated. Film formation by a coating method such as a spin coating method, an ink jet method, a printing method, or a spray method is preferable.

  Examples of the liquid medium for dissolving or dispersing the organic EL device 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, Aromatic hydrocarbons such as mesitylene and 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 forming these layers, a thin film made of a cathode material is formed thereon by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably 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 in the range of 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 such as a display device or a display, or various light emitting 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-2000 (manufactured by Konica Minolta Sensing) is applied to the CIE chromaticity coordinates.

When the organic EL element of the present invention is a white element, 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. = 0.35 ± 0.1, Y = 0.35 ± 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.

<< Production of organic EL element >>
(1) Sample No. 1. Production of Organic EL Element (1.1) Production of Gas Barrier Flexible Film As a flexible film, an anode of a polyethylene naphthalate film (Teijin DuPont film, hereinafter abbreviated as PEN) is formed. An inorganic gas barrier film made of SiOx has a thickness of 500 nm continuously on a flexible film using an atmospheric pressure plasma discharge treatment apparatus having the structure described in JP-A-2004-68143 on the entire surface on the side. A gas barrier flexible film having an oxygen permeability of 0.001 ml / m ² / day or less and a water vapor permeability of 0.001 g / m ² / day or less was produced.

(1.2) Formation of Anode A 120 nm thick ITO (indium tin oxide) film was formed by sputtering on the prepared gas barrier flexible film, and patterned by photolithography to form an anode.
The pattern was such that the light emission area was 50 mm square.

(1.3) Formation of hole injection layer The patterned ITO substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes. On this substrate, poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (abbreviated as PEDOT / PSS, manufactured by Bayer, Baytron P Al 4083) diluted to 70% with pure water was used at 3000 rpm, 30 A thin film was formed by spin coating under the conditions of seconds, and then dried at 200 ° C. for 1 hour to provide a hole injection layer having a thickness of 30 nm.

(1.4) Formation of hole transport layer This substrate was transferred to a nitrogen atmosphere using nitrogen gas (grade G1), and a hole transport layer composition having the following composition was used. Spinning was performed at 1500 rpm for 30 seconds. After forming a thin film by the coating method, it was kept at 160 ° C. for 30 minutes to provide a hole transport layer having a thickness of 30 nm.

<Hole transport layer composition>
Hole transport material (60) (weight average molecular weight Mw = 80000) 5 parts by mass Chlorobenzene 1000 parts by mass

(1.5) Formation of Light-Emitting Layer Next, a light-emitting layer composition having the following composition was used to form a thin film by spin coating under conditions of 1500 rpm and 30 seconds, and then held at 120 ° C. for 30 minutes to emit light with a thickness of 50 nm. A layer was provided.

<Light emitting layer composition>
Host compound OC-29 8.78 parts by mass Phosphorescence emission dopant compound DP-1 3.01 parts by mass Phosphorescence emission dopant compound D-67 0.05 parts by mass Phosphorescence emission dopant compound D-75 0.05 parts by mass Acetic acid Isopropyl 2000 parts by mass

(1.6) Formation of Electron Transport Layer Subsequently, using an electron transport layer composition (coating liquid) having the following composition, a thin film was formed by spin coating under conditions of 1000 rpm and 30 seconds, and then at 120 ° C. for 30 minutes. An electron transport layer having a thickness of 30 nm was provided. In addition, cesium acetate is added to the following electron transport layer composition as a metal compound (another metal compound) of an alkali metal or an alkaline earth metal.

<Electron transport layer composition>
8-hydroxyquinolinato lithium 0.3 parts by mass Electron transporting compound HS-6 2.7 parts by mass Cesium acetate 0.18 parts by mass 1,1,1,3,3,3-hexafluoroisopropanol 800 parts by mass Ethanol ( 200 parts by weight

  In addition, sample No. described later. In samples where the quinolinate complex or the electron transport compound is “none”, such as the organic EL devices of 13, 15, and 16 (see Table 1), the quinolinate complex and the electron transport compound can be obtained using only other materials to be added. Preparation was performed so as to satisfy the total amount (3 parts by mass).

(1.7) Formation of electron injection layer and cathode Subsequently, the substrate was attached to a vacuum deposition apparatus without being exposed to the atmosphere. A molybdenum resistance heating boat containing sodium fluoride and potassium fluoride is attached to a vacuum deposition apparatus, and after the vacuum chamber is depressurized to 4 × 10 ⁻⁵ Pa, the boat is energized and heated. Sodium fluoride was vapor-deposited on the electron transport layer at 0.02 nm / second to form a thin film having a thickness of 1 nm, and potassium fluoride was similarly vapor-deposited on the thin film at 0.02 nm / second, An electron injection layer having a thickness of 1.5 nm was provided.
Subsequently, aluminum was deposited on the electron injection layer to provide a cathode having a thickness of 100 nm.

(1.8) Sealing and Production of Organic EL Element Subsequently, a sealing member was adhered using a commercially available roll laminating apparatus, and sample No. 1 organic EL element was produced.

  Specifically, as a sealing member, a flexible aluminum foil (made by Toyo Aluminum Co., Ltd.) having a thickness of 30 μm, a polyethylene terephthalate (PET) film (12 μm thickness) and an adhesive for dry lamination (two-component reaction type urethane) (Adhesive layer thickness 1.5 μm) was used.

A thermosetting adhesive was uniformly applied to the aluminum surface as a sealing adhesive with a thickness of 20 μm along the adhesive surface (glossy surface) of the aluminum foil using a dispenser. This was dried under a vacuum of 100 Pa or less for 12 hours. Furthermore, it moved to nitrogen atmosphere with a dew point temperature of −80 ° C. or lower and an oxygen concentration of 0.8 ppm, dried for 12 hours or longer, and adjusted the moisture content of the sealing adhesive to 100 ppm or lower.
As the thermosetting adhesive, an epoxy adhesive mixed with the following (A) to (C) was used.

(A) Bisphenol A diglycidyl ether (DGEBA)
(B) Dicyandiamide (DICY)
(C) Epoxy adduct curing accelerator

  As described above, the sealing member is closely attached and arranged so as to cover the joint between the extraction electrode and the electrode lead, and the thickening condition, the pressure roll temperature of 120 ° C., the pressure of 0.5 MPa, and the apparatus using the pressure roll. The sample No. 2 was tightly sealed at a speed of 0.3 m / min. 1 organic EL element.

(2) Sample No. Preparation of organic EL elements 2 to 16 In the production of the organic EL element 1, the quinolinate complex, the electron transporting compound, the other metal compound, and the solvent as the material for the electron transporting layer were changed as shown in Table 1.
Other than that, in the same manner, sample No. 2 to 16 organic EL elements were produced.
In addition, what was evaluated as “x” in the solubility evaluation described later was not manufactured as an organic EL element because the material of the electron transport layer was not dissolved in the solvent and the electron transport layer could not be formed. .

<< Evaluation of organic EL elements >>
Sample No. The following evaluations were performed on 1 to 16 organic EL elements.

(1) Evaluation of solubility Sample No. About the electron carrying layer composition used for preparation of the organic EL element of 1-16, visual evaluation was performed about the solubility of the material immediately after preparation, and precipitation of the material after 1 day standing.
The evaluation results are shown in Table 1. The evaluation results shown in Table 1 are based on the following criteria.

○: colorless and transparent, no undissolved residue and no precipitation.
(Triangle | delta): It is colorless and transparent immediately after melt | dissolution, and there is no undissolved residue, but a coating liquid becomes cloudy after leaving still for one day.
X: The coating solution becomes cloudy.

(2) Evaluation of lamination property Sample No. In the same manner as the method for forming the light emitting layer and the electron transport layer of the organic EL elements 1 to 16, a sample formed by laminating the light emitting layer and the electron transport layer on the quartz substrate, and only the light emitting layer was formed on the quartz substrate. Samples were prepared, and the film thickness of the light emitting layer of each sample was measured and compared using a reflection spectral film thickness meter (FE-3000 manufactured by Otsuka Electronics Co., Ltd.).
Sample No. Luminance unevenness of light emission when the organic EL elements 1 to 16 were made to emit light after production was visually evaluated.
The evaluation results are shown in Table 1. The evaluation results shown in Table 1 are based on the following criteria.

○: The thickness of the light emitting layer of the sample in which the light emitting layer and the electron transporting layer are laminated is 95% or more of the thickness of the light emitting layer of the sample in which only the light emitting layer is formed, and the loss of the lower layer (light emitting layer) is extremely small. Also, there is no light emission luminance unevenness of the organic EL element.
Δ: The light emitting layer thickness of the sample in which the light emitting layer and the electron transport layer are laminated is 90% or more of the light emitting layer thickness of the sample in which only the light emitting layer is formed, and the lower layer (light emitting layer) is less lost. The light emission luminance unevenness of the organic EL element is slightly seen.
X: The light emitting layer film thickness of the sample in which the light emitting layer and the electron transport layer are laminated is less than 90% of the light emitting layer film thickness of the sample in which only the light emitting layer is formed, and the loss of the lower layer (light emitting layer) is observed, The light emission luminance unevenness of the organic EL element is observed.

(3) Measurement of drive voltage and luminous efficiency Sample No. The organic EL elements 1 to 16 are lit at a constant current density of ^2.5 mA / cm ² at room temperature (in the range of about 23 to 25 ° C.), and a spectral radiance meter CS-2000 (Konica Minolta). The light emission luminance of each element was measured using Sensing Corp., and the drive voltage and the light emission efficiency (external extraction efficiency) at the current value were determined.
The evaluation results are shown in Table 1.
Note that the driving voltage and the light emission efficiency are the same as in sample No. The driving voltage and luminous efficiency of 13 organic EL elements were expressed as relative values.
In Table 1, it is shown that the smaller the numerical value of the driving voltage and the larger the numerical value of the light emission efficiency, the lower the power driving and the higher the efficiency.

(4) Evaluation of continuous drive stability (half life) 1 to 16 organic EL elements are wound around a cylinder having a radius of 5 cm, and then each element is continuously driven in a bent state, and the luminance is measured using the spectral radiance meter CS-2000, and the measured luminance is halved. Time (LT50) was determined. The driving condition was set to a current value of 4000 cd / m ² at the start of continuous driving.
The evaluation results are shown in Table 1.
In addition, the half life is the sample No. It represented with the relative value which sets the half life of 13 organic EL elements to 100.
In Table 1, it shows that it is excellent in continuous drive stability (long life), so that a numerical value is large.

(5) Measurement of solvent content Sample No. In the same manner, devices that do not perform cathode film formation and sealing in the organic EL devices 1 to 16 were prepared, and the temperature-programmed desorption spectrum of these devices was measured using TDS1200 manufactured by Denshi Kagaku Co., Ltd. The content was calculated. In addition, solvent content is sample No. It represented with the relative value which makes the solvent content of 13 organic EL elements 100.
In Table 1, it shows that there are few solvent contents, so that a numerical value is small.

(6) Evaluation of reliability at high temperature storage In the continuous drive stability evaluation of (4) above, evaluation was performed in the same manner except that the storage was performed in an environment of 85 ° C.
The evaluation results are shown in Table 1.
In Table 1, the larger the value, the better the reliability at high temperature storage.

(7) Summary As shown in Table 1, sample No. The organic EL elements 1 to 12 have the sample numbers of Comparative Examples. As compared with the organic EL elements of 13 to 16, it is clear that the element material is excellent in solubility, stackability, luminous efficiency, driving voltage, lifetime and reliability at high temperature storage.
As described above, the electron transporting compound is mixed with the quinolinato complex represented by the general formula (1) and the non-fluorinated alcohol solvent to prepare a coating solution, and the coating solution is applied and dried to form an electron transporting layer. It turns out to be useful.

  In particular, the organic EL element in the present invention is useful when used in a display device and a lighting device.

DESCRIPTION OF SYMBOLS 1 Support substrate 2 Anode 3 Hole injection layer 4 Hole transport layer 5 Light emitting layer 6 Electron transport layer 7 Electron injection layer 8 Cathode 9 Sealing adhesive 10 Sealing member 20 Laminate 100 Organic EL element

Claims (10)

A pair of electrodes provided on the substrate, at least one light emitting layer disposed between the pair of electrodes, and an electron transport layer disposed between any one of the pair of electrodes and the light emitting layer In an organic electroluminescence device comprising:
The electron transport layer is
An electron transport compound, and quinolinato complexes of lithium, the coating liquid thus prepared is dissolved in a non-fluorinated alcohol solvent state, and are not formed by being dried is applied,
The organic luminescence device, wherein the lithium quinolinato complex is represented by the following general formula (1) .

[Wherein n represents 1 or 2. R1 to R6 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 hydrocarbon It represents a cyclic group or a non-aromatic heterocyclic group, and may further have a substituent. Any one of R1 to R6 may be bonded to form a ring. X represents an optionally different ligand, and m represents 0 or an integer of 1 or more. M represents lithium. ] 2. The organic electroluminescence device according to claim 1 , wherein the coating solution further contains a metal compound of an alkali metal or alkaline earth metal other than lithium. Wherein the coating solution, the organic electroluminescent device according to claim 1 or 2 further characterized in that the fluorinated alcohol solvent is contained. The organic electroluminescence device according to any one of claims 1 to 3 , wherein the electron transporting compound is represented by the following general formula (2).
General formula (2)
Qm-Ln
[In the formula, L represents a condensed aromatic heterocyclic ring, Q represents an aromatic hydrocarbon ring or an aromatic heterocyclic ring, and n and m each represent an integer of 1 to 3. When n is 2 or more, L may be different from each other, and when m is 2 or more, Q may be different from each other. ] The organic electroluminescence device according to claim 4 , wherein L in the general formula (2) has a partial structure represented by the following general formula (3).

[Wherein, A represents O, S, or N (R1), and A11 to A18 each represent a nitrogen atom or C (R2). R1 and R2 each represent a bond, a hydrogen atom or a substituent. However, when there are a plurality of C (R2), each C (R2) may be the same or different. ] The organic electroluminescent device according to claim 4 or 5 compound represented by the general formula (2), characterized in that at least one of the pyridine ring as a partial structure. The organic electroluminescence device according to any one of claim 1 to 6, wherein the light emitting layer, wherein the low molecular compound containing no repeating units of a molecular weight of 3,000 or less is contained. Display device characterized by comprising the organic electroluminescence device according to any one of claims 1-7. An illuminating device comprising the organic electroluminescence element according to any one of claims 1 to 7 . A pair of electrodes provided on the substrate, at least one light emitting layer disposed between the pair of electrodes, and an electron transport layer disposed between any one of the pair of electrodes and the light emitting layer In a manufacturing method of an organic electroluminescence device comprising:
A step of preparing a coating solution by dissolving an electron transporting compound and a lithium quinolinate complex in a non-fluorinated alcohol solvent;
Forming the electron transport layer by applying and drying the coating solution ,
The method for producing an organic electroluminescence device, wherein the lithium quinolinato complex is represented by the following general formula (1) .

[Wherein n represents 1 or 2. R1 to R6 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 hydrocarbon It represents a cyclic group or a non-aromatic heterocyclic group, and may further have a substituent. Any one of R1 to R6 may be bonded to form a ring. X represents an optionally different ligand, and m represents 0 or an integer of 1 or more. M represents lithium. ]

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