JP5568943B2 - ORGANIC ELECTROLUMINESCENCE ELEMENT AND LIGHTING DEVICE - Google Patents

Description

  The present invention relates to an organic electroluminescence element and a lighting device.

  An organic electroluminescence element (hereinafter also referred to as an organic EL element) is an all-solid-state element composed of an organic material film having a thickness of only about 0.1 μm between electrodes, and emits light of 2V to 20V. Since it can be achieved at a relatively low voltage, it is a technology expected as a next-generation flat display and illumination.

The discovery of an organic EL device using phosphorescence emission enables a light emission efficiency of about 4 times in principle compared to the previous method using fluorescence emission. Research and development on composition is conducted all over the world. (For example, MA Baldo et al., Nature, 395, 151-154 (1998), MA Baldo et al., Nature, 403, 17, 750-753 (2000). US Pat. No. 6,097,147, S. Lamansky et al., J. Am. Chem. Soc., 123, 4304 (2001))
In recent years, the attractiveness of organic EL elements as surface-emitting light sources has increased, and the necessity for satisfying all of “high efficiency, high luminance, and long life” has been increased due to their functions as commercial products. Many inventions for these requirements have been made so far, but generally, the element lifetime of organic EL is in a trade-off relationship with light emission luminance, and it is impossible to achieve both high luminance and long lifetime (for example, , Organic EL device physics / material chemistry / device application, CMC Publishing, pages 257-267 (2007)). As a technical solution to this dilemma, organic EL elements having a multi-unit structure in which organic EL elements are connected in series have been reported (for example, Patent Documents 1 and 2).

Japanese Patent No. 3884564 Japanese Patent No. 3933591

  In an organic electroluminescence device having a multi-unit structure, luminance deterioration at the initial stage of driving due to the charge generation layer material and voltage increase with time are problems, and the object of the present invention is to solve these problems. is there.

  The above object of the present invention is achieved by the following means.

1. In an organic electroluminescence device having a charge generation layer that generates holes and electrons by applying an electric field between a plurality of light emitting units,
The charge generation layer includes an organic donor and an organic acceptor,
Organic donor or organic acceptor, compound or an organic electroluminescence device in which the derivatives are characterized polymer der Rukoto that multidimensional crosslinking having a partial structure represented by the following general formula (A).

(Wherein X ₁ , X ₂ , X ₃ and X ₄ are each independently N or CR, R represents a hydrogen atom, an alkyl group, an alkoxy group, an aryl group or a heteroaryl group. M is H ₂ , the metal atom represented by .M representing a metal atom, T iO or VO _{is, Co, Fe, Mg, Li} 2, Ru, Zn, Cu, Ni, Na 2, Cs 2 or a Sb.)

2 . 2. The organic electroluminescence device as described in 1 above, which emits phosphorescence.

3 . 3. An illuminating device using the organic electroluminescence element according to any one of 1 or 2 above.

  According to the present invention, a novel material is found as a charge generation layer material that plays an important role in an organic electroluminescence (EL) device having a multi-unit structure, and the voltage is reduced. Furthermore, it succeeded in suppressing the luminance deterioration at the initial stage of driving and suppressing the voltage rise with time.

It is the schematic diagram which showed an example of the display apparatus comprised from an organic EL element. 4 is a schematic diagram of a display unit A. FIG. It is a schematic diagram of a pixel. It is a schematic diagram of a passive matrix type full-color display device. It is the schematic of an illuminating device. It is a schematic diagram of an illuminating device. The schematic block diagram of an organic electroluminescent full color display apparatus is shown.

  When the organic EL element material of the present invention was used, it was possible to provide an organic EL element in which luminance deterioration was suppressed at the initial stage of driving and voltage increase with time was suppressed. In addition, a display device and a lighting device including the element can be provided.

  Hereinafter, details of each component according to the present invention will be sequentially described.

<< Constitutional layer of organic EL element, organic compound layer >>
The layer structure of the organic EL element of the present invention will be described. Although the preferable specific example of the layer structure of the organic EL element of this invention is shown below, this invention is not limited to these.
(1) Anode / (light emitting unit / CGL) n / light emitting unit / cathode () represents a repeating unit, n represents the number of repetitions, and is an integer from 1 to 100.

  The light-emitting unit (also referred to as an organic compound layer) of the organic EL element of the present invention, its layer configuration and the like will be described. Although the preferable specific example of the organic compound layer structure of the light emission unit of the organic EL element of this invention is shown below, this invention is not limited to these.

(I) Hole transport layer / light emitting layer / electron transport layer (ii) Hole transport layer / light emitting layer / hole blocking layer / electron transport layer (iii) Hole transport layer / light emitting layer / hole blocking layer / electron Transport layer / cathode buffer layer (iv) Anode buffer layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer << Organic compound layer (also referred to as organic layer) >>
The organic compound layer constituting the light emitting unit according to the present invention will be described.

  The organic EL device of the present invention preferably has a plurality of organic compound layers as a constituent layer, and examples of the organic compound layer include a hole transport layer, a light emitting layer, and a hole blocking layer in the above-described layer configuration. As the organic compound layer according to the present invention, an organic compound contained in a constituent layer of the organic EL element, such as a hole injection layer or an electron injection layer, is included. Defined. Further, when an organic compound is used for the anode buffer layer, the cathode buffer layer, and the like, the anode buffer layer, the cathode buffer layer, and the like each form an organic compound layer.

  The organic compound layer includes a layer containing “organic EL element material that can be used for a constituent layer of an organic EL element” or the like.

  In the organic EL device of the present invention, the light emitting maximum wavelength of the blue light emitting layer is preferably 430 nm to 480 nm, the green light emitting layer has a light emitting maximum wavelength of 510 nm to 550 nm, and the red light emitting layer has a light emitting maximum wavelength of 600 nm to 640 nm. A monochromatic light emitting layer in the range is preferable, and a display device using these is preferable.

  Alternatively, a white light emitting layer may be formed by laminating at least three light emitting layers. Further, a non-light emitting intermediate layer may be provided between the light emitting layers.

  The organic EL element 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 of this invention is demonstrated.

<Charge generation layer (CGL)>
<< Layer structure of charge generation layer >>
The layer structure of the charge generation layer of the present invention will be described. The layers shown in the following (1) to (10) can be used as the charge generation layer of the present invention singly or arbitrarily in combination.

  In the present invention, the charge generation layer is formed of at least one layer.

  The charge generation layer desirably has a conductivity higher than that of a semiconductor, but is not limited thereto.

  The charge generation layer is a layer that generates holes and electrons when an electric field is formed, but the generation interface may be in the charge generation layer, or at or near the interface between the charge generation layer and another layer. good.

  For example, when the charge generation layer is a single layer, the charge generation of electrons and holes may be within the charge generation layer, or may be at the interface between the adjacent layer and the charge generation layer.

  In the present invention, more preferably, the charge generation layer comprises two or more layers, and preferably includes one or both of a p-type semiconductor layer and an n-type semiconductor layer.

  The charge generation layer may function as a hole injection layer, a hole transport layer, an electron transport layer, or an electron injection layer and can be used as the same layer, but the charge generation layer generates holes and electrons. A layer or a layer having an interface.

The structure of the charge generation layer in the present invention is as follows.
1. 1. Light emitting unit / bipolar layer (one layer) / light emitting unit 2. Light emitting unit / n-type layer / p-type layer / light emitting unit Light emitting unit / n-type layer / intermediate layer / p-type layer / light emitting unit The bipolar layer is a layer capable of generating and transporting holes and electrons inside the layer by an external electric field.

  The n-type layer is a charge transport layer in which majority carriers are electrons, and preferably has conductivity higher than that of a semiconductor.

  The p-type layer is a charge transport layer in which majority carriers are holes, and preferably has conductivity higher than that of a semiconductor.

  The intermediate layer may be provided if necessary for improving the charge generation ability and long-term stability. For example, the diffusion prevention layer of n-type layer and p-type layer or the reaction suppression layer between pn, Examples include a level adjusting layer that adjusts the charge level of the p-type layer and the n-type layer.

  A bipolar layer, a p-type layer, and an n-type layer may be further provided between the light emitting unit and the charge generation layer.

  In the present invention, these layers are included in the light emitting unit and are not regarded as charge generating layers, although they may be provided if necessary when the generated charge is quickly injected into the light emitting unit.

  In the present invention, the charge generation layer is preferably formed of at least two layers, and refers to a layer having a function of injecting holes in the cathode direction and electrons in the anode direction when a voltage is applied. .

  The layer interface of the charge generation layer consisting of two or more layers may have an interface (heterointerface, homointerface), and form a multidimensional interface such as a bulk heterostructure, islands, or phase separation. May be.

  The thickness of each of the two layers is preferably 1 nm or more and 100 nm or less, and more preferably 10 nm or more and 50 nm or less.

  As for the light transmittance of the charge generation layer of the present invention, it is desirable to have a high transmittance for the light emitted from the light emitting layer. In order to sufficiently extract light and obtain sufficient luminance, the transmittance at a wavelength of 550 nm is desirably 50% or more, and more preferably 80% or more.

  One of the two or more charge generation layers includes an inorganic compound or an organic compound having a work function of 3.0 eV or less, and the other layer has a work function of 4.0 eV or more. An inorganic compound or an organic compound can be preferably used.

  More preferably, one of the charge generation layers composed of two or more layers is a metal having a work function of 3.0 eV or less, or an inorganic oxide, an inorganic salt, an organometallic complex, or an organic salt. The layer is a metal having a work function of 4.0 eV or more, or an inorganic oxide, an inorganic salt, an organometallic complex, or an organic salt.

  Examples of the organic compound of the present invention include nanocarbon materials, compounds represented by general formulas (A), (D), (F), (G), (H), and (J), imidazole radicals, metallocene derivatives, Examples thereof include polycyano derivatives and polynitro derivatives.

  Specific examples of the material constituting the charge generation layer of the present invention are shown below, but the present invention is not limited thereto.

<Nanocarbon material>
The nanocarbon material refers to a carbon material having a particle diameter of 1 nanometer to 500 nanometers, and representative examples thereof include carbon nanotubes, carbon nanofibers, fullerenes and derivatives thereof, carbon nanocoils, carbon onion fullerenes and derivatives thereof, Examples include diamond, diamond-like carbon, and graphite.

  In particular, fullerenes and fullerene derivatives can be preferably used. The fullerene in the present invention is a closed polyhedral cage molecule having 12 pentagonal planes composed of 20 or more carbon atoms and (n / 2-10) hexagonal planes. The derivative is called a fullerene derivative. Although it will not specifically limit if carbon number of a fullerene skeleton is 20 or more, Preferably it is C60, 70, 84. Examples of fullerene and fullerene derivatives are shown below, but the present invention is not limited thereto.

  R represents a hydrogen atom or a substituent, and n represents an integer of 1 to 12.

  Preferred substituents represented by R include alkyl groups (methyl group, ethyl group, i-propyl group, hydroxyethyl group, methoxymethyl group, trifluoromethyl group, t-butyl group, cyclopentyl group, cyclohexyl group, benzyl group). Group), aryl group (phenyl group, naphthyl group, p-tolyl group, p-chlorophenyl group, etc.), heteroaryl group (pyrrole group, imidazolyl group, pyrazolyl group, pyridyl group, benzimidazolyl group, benzothiazolyl group, benzooxa Zolyl group, triazolyl group, oxadiazolyl group, thiadiazolyl group, thienyl group, carbazolyl group, etc.), alkenyl group (vinyl group, propenyl group, styryl group etc.), alkynyl group (ethynyl group etc.), alkyloxy group (methoxy group, Ethoxy group, i-propoxy group, butoxy group, etc.) Aryloxy group (phenoxy group etc.), alkylthio group (methylthio group, ethylthio group, i-propylchio group etc.), arylthio group (phenylthio group etc.), amino group, alkylamino group (dimethylamino group, diethylamino group, ethylmethylamino) Group), arylamino group (anilino group, diphenylamino group, etc.), halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), cyano group, nitro group, non-aromatic heterocyclic group (pyrrolidyl group) , Pyrazolyl group, imidazolyl group, etc.), silyl group (trimethylsilyl group, t-butyldimethylsilyl group, dimethylphenylsilyl group, triphenylsilyl group, etc.), etc., and each substituent further has a substituent. It may be.

Here, R ₁ , R ₂ , and R ₃ each independently represent hydrogen or a substituent similarly to R, and X represents — (CR ₁ R ₂ ) m— or —CH ₂ —NR _1. Represents a divalent group represented by —CH ₂ — and the like. Here, groups such as R ₁ , R ₂ and R ₃ represent a hydrogen atom or a substituent, n represents an integer of 1 to 12, and m represents an integer of 1 to 4. As a substituent, it is synonymous with the substituent represented by said R.

Here, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ , R ₈ , R _{9 to} R ₁₃ each represent a hydrogen atom or a substituent, and are represented by R _{1 to} R _13. The substituent is as defined for R. N represents an integer of 1 to 4. M represents a transition metal atom, and L represents a ligand coordinated to the metal atom. The ligand is not limited as long as it is a molecule or ion constituting the ligand in a normal metal complex. Here, m represents an integer of 1 to 5.

  Specific examples of these fullerenes and fullerene derivatives are illustrated below, but are not limited thereto.

  Examples of organic compounds and the like constituting the charge generation layer of the present invention according to the present invention are shown below.

(1) As a material constituting the charge generation layer of the present invention, a compound represented by the general formula (A) may be mentioned. In the general formula (A), X ₁ , X ₂ , X ₃ and X ₄ are each independently N or —CR, and R represents a hydrogen atom, an alkyl group, an alkoxy group, an aryl group or a heteroaryl group. M represents a metal atom, H ₂ , TiO, or VO. Moreover, you may have a substituent on a porphyrin ring. The metal represented by _M, a Co, Fe, Mg, Li 2 , Ru, Zn, Cu, Ni, Na 2, Cs 2 or Sb. X ₁ , X ₂ , X ₃ , and X ₄ are preferably N or —CAr (Ar = aromatic hydrocarbon, aromatic heterocycle), and more preferably —CPh. M is preferably Co, Li ₂ , Zn, Cu, Ni, Na ₂ , or Cs ₂ , and more preferably Co.

  Specific examples of the porphyrin derivative are shown below, but the present invention is not limited thereto.

(2) The imidazole radicals, which are materials constituting the charge generation layer of the present invention, are compounds that generate imidazole radicals by light or heat, specifically, compounds represented by the general formula (E) R ₁ , R ₂ and R ₃ may represent a hydrogen atom or a substitution, and R ₂ and R ₃ may form a ring.

  Specific examples of the imidazole radical derivative represented by the general formula (E) are shown below, but the present invention is not limited thereto.

(3) As a material constituting the charge generation layer of the present invention, a compound represented by the general formula (D) may be mentioned. In the compound represented by the general formula (D), X ₁ , X ₂ , X ₃ and X ₄ are each independently S, Se, Te or NR. R represents a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or a heteroaryl group. R ₁ , R ₂ , R ₃ and R ₄ are each independently a hydrogen atom or a substituent, and R ₁ and R ₂ , or R ₃ and R ₄ may be bonded to each other to form a ring. M _{is H 2, Co, Fe, Mg} , Li 2, Ru, Zn, Cu, Ni, Na 2, Cs 2 or Sb.

X ₁ , X ₂ , X ₃ and X ₄ are preferably S. R ₁ , R ₂ , R ₃ and R ₄ are preferably aromatic hydrocarbons or aromatic heterocycles, and more preferably aromatic hydrocarbons. M is preferably Co, Fe, Zn, Cu, or Ni, and more preferably Ni.

  Although the specific example of a compound represented by general formula (D) is shown below, this invention is not limited to these.

(4) As a material constituting the charge generation layer of the present invention, a compound represented by the general formula (G) can be given. In the general formula (G), X ₁ , X ₂ , X ₃ , and X ₄ are each independently S, Se, Te, or NR. X ₅ , X ₆ , X ₇ , X ₈ are each independently O, S, Se, Te, and M is H ₂ , Co, Fe, Mg, Li ₂ , Ru, Zn, Cu, Ni, Na ₂ , Cs ₂ or Sb.

  M is preferably Co, Fe, Mg, Zn, Cu, or Ni, and more preferably Ni.

  Specific examples of the compound represented by the general formula (G) are given below.

(5) Examples of the material constituting the charge generation layer of the present invention include a compound represented by the general formula (F). In the general formula (F), R ₁ , R ₂ , R ₃ , and R ₄ are hydrogen atoms or substituents, and R ₁ and R ₂ , and R ₃ and R ₄ may be bonded to each other to form a ring. .

  Specific examples of the DCNQI derivative represented by the general formula (F) are shown below, but the present invention is not limited thereto.

(6) As a material constituting the charge generation layer of the present invention, a compound represented by the general formula (H) can be given. In the general formula (H), X ₁ , X ₂ , X ₃ , X ₄ , X ₅ , X ₆ , X ₇ , X ₈ are each independently N or CR. R represents a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or a heteroaryl group. R ₁ is a hydrogen atom or a substituent.

  Specific examples of the azacarbazole derivative represented by the general formula (H) are shown below, but the present invention is not limited thereto.

(7) As a material constituting the charge generation layer of the present invention, a compound represented by the following general formula (J) can be given. In the general formula (J), a, b, c, d, and e are —NR _n1. —, —CR _c1 R _c2 —, wherein R _n1 , R _c1 and R _c2 are each independently a hydrogen atom or a substituent, E is N, —CR _c3 —, and R _c3 is a hydrogen atom. Or it is a substituent. M represents Mo and W, and n and m represent 0 to 5.

  Although the specific example of a compound represented by general formula (J) is shown below, this invention is not limited to these.

  (8) Examples of the metallocene derivative include ferrocene, cobaltcene, and nickelocene, and these may have a substituent. Examples of metallocene derivatives include the following: Ferrocene is preferable.

  (9) Examples of polycyano derivatives include the following.

  (10) Examples of polynitro derivatives include trinitrobenzene, picric acid, dinitrophenol, dinitrobiphenyl, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 9- Examples thereof include dicyanomethylene 2,4,7-trinitrofluorenone and 9-dicyanomethylene 2,4,5,7-tetranitrofluorenone.

  (11) As an example of the nanocarbon material, the above-mentioned nanocarbon material can be used. Preferably, the above-mentioned fullerene derivative is raised.

  As the charge generation layer, the above materials can be used alone or in combination of two or more.

  When using 2 or more types together, it is preferable to use an organic donor compound and an organic acceptor compound in combination.

  Examples of the organic donor include general formula (A), general formula (D), general formula (J), imidazole radicals, metallocene derivatives, and nanocarbon derivatives.

  Examples of the organic acceptor include general formula (F), general formula (G), general formula (H), polycyano derivatives, and polynitro derivatives.

  Moreover, when using 2 or more types together, compounds other than the compound of this invention can be used in further combination with the compound of this invention.

  Specific examples of the compound used other than the compound of the present invention include the following.

(1) A phthalocyanine derivative is exemplified, and examples of the phthalocyanine derivative are compounds represented by the following general formula (1), and X ₁ , X ₂ , X ₃ , and X ₄ are each independently N or —CR. Yes, R represents a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or a heteroaryl group. M represents H ₂ or a metal atom. Moreover, you may have a substituent on a phthalocyanine ring. M is _{preferably, H 2, Co, Fe,} Mg, Li 2, Ru, Zn, Cu, Ni, Na 2, Cs 2 or Sb.

  Specific examples of the phthalocyanine derivative are shown below, but the present invention is not limited thereto.

(2) The compound represented by General formula (2) is mentioned. In the general formula (B), X ₁ , X ₂ , X ₃ and X ₄ are each independently S, Se or Te, and R ₁ , R ₂ , R ₃ and R ₄ are a hydrogen atom or a substituent. , R ₁ and R ₂ , R ₃ and R ₄ may be bonded to each other to form a ring. X ₁ , X ₂ , X ₃ and X ₄ are preferably S and Se.

  Specific examples of the TTT derivative represented by the general formula (2) are shown below, but the present invention is not limited thereto.

(3) A tetrathiafulvalene (TTF) derivative represented by the general formula (3) is exemplified, and in the general formula (3), X ₁ , X ₂ , X ₃ and X ₄ are each independently S, Se, or Te, R ₁ , R ₂ , R ₃ and R ₄ are hydrogen atoms or substituents, and R ₁ and R ₂ , R ₃ and R ₄ may be bonded to each other to form a ring.

  Specific examples of the TTF derivative represented by the general formula (3) are shown below, but the present invention is not limited thereto.

  (4) Examples of the condensed polycyclic aromatic hydrocarbon include naphthalene, anthracene, phenanthrene, pyrene, triphenylene, chrysene, tetracene, pentacene, perylene, obalene, circumanthracene, anthanthrene, pyranthrene, and rubrene.

  (5) Examples of arylamine derivatives include diethylaminobenzene, aniline, toluidine, anisidine, chloroaniline, diphenylamine, indole, skatole, p-phenylenediamine, durenediamine, N, N, N, N tetramethyl-p-phenylene. Examples thereof include diamine, benzidine, N, N, N, N tetramethylbenzidine, tetrakisdimethylaminopyrene, tetrakisdimethylaminoethylene, biimidazole, m-MDTATA, and α-NPD.

  (6) Examples of azine derivatives are cyanine dyes, carbazole, acridine, phenazine, N, N-dihydrodimethylphenazine, phenoxazine, and phenothiazine.

  (7) Examples of trialamine derivatives are shown below.

(8) Examples of the quinone derivative is a compound represented by the general formula _{(4), R 1, R} 2, R 3, R 4 is a hydrogen atom or a substituent, _{R 1} and _R 2, R ₃ and R ₄ may combine with each other to form a ring. R ₁ , R ₂ , R ₃ and R ₄ are preferably a halogen atom or a cyano group.

  Specific examples of the quinone derivative are shown below, but the present invention is not limited thereto.

(9) An example of a tetracinoaquinodimethane derivative is a compound represented by the following general formula (5), wherein R ₁ , R ₂ , R ₃ , and R ₄ are a hydrogen atom or a substituent, and R ₁ And R ₂ , R ₃ and R ₄ may be bonded to each other to form a ring.

  Specific examples of the tetracinoaquinodimethane derivative represented by the general formula (5) are shown below, but the present invention is not limited thereto.

(10) Examples of the phenanthroline derivative are compounds represented by the following general formula (6), and R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ , and R ₈ are hydrogen atoms. Or it is a substituent.

  Specific examples of the phenanthroline derivative represented by the general formula (6) are shown below, but the present invention is not limited thereto.

  (11) Examples of quinolinol metal complex derivatives are compounds having a partial structure of the general formula (7), and M is preferably Al, Co, Fe, Mg, Ru, Zn, Cu, or Ni.

  Specific examples of the quinolinol metal complex derivative represented by the general formula (7) are shown below, but the present invention is not limited thereto.

  (12) Heteroaromatic hydrocarbon compounds (In the present invention, heteroaromatic hydrocarbon compounds are heteroaromatic compounds in which one or more of the carbon atoms in the aromatic hydrocarbon compound are heterogeneous such as oxygen, sulfur, nitrogen, phosphorus, boron, etc. In particular, pyridine derivatives substituted with a nitrogen atom can be used, and specific examples thereof are shown below.

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

  The total 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 a 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 nm to 200 nm, and particularly preferably in the range of 10 nm to 20 nm.

  For the production of the light-emitting layer, a light-emitting dopant or a host compound, which will be described later, is formed by a known thinning method such as a vacuum deposition method, a spin coating method, a casting method, an LB method, or an ink-jet method. it can.

  The light emitting layer of the organic EL device of the present invention preferably contains a light emitting host compound and at least one kind of light emitting dopant (phosphorescent dopant (also referred to as phosphorescent dopant) or fluorescent dopant). .

(Host compound (also called luminescent host))
The host compound used in the present invention will be described.

  Here, the host compound in the present invention is a phosphorescent quantum yield of phosphorescence emission at a room temperature (25 ° C.) having a mass ratio of 20% or more in the compound contained in the light emitting layer. Is defined as a compound of less than 0.1. The phosphorescence quantum yield is preferably less than 0.01. Moreover, it is preferable that the mass ratio in the layer is 20% or more among the compounds contained in a light emitting layer.

  In the present invention, the compound having the carbazole ring as a partial structure, the compound having a polymerizable group and having the carbazole ring as a partial structure, and a polymer of the compound are particularly preferably used as the host compound.

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

  A conventionally known host compound that may be used in combination is preferably a compound that has a hole transporting ability and an electron transporting ability, prevents the emission of light from becoming longer, and has a high Tg (glass transition temperature). .

  Specific examples of conventionally known host compounds include the compounds shown below or the 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.

(Luminescent dopant)
The light emitting dopant according to the present invention will be described.

  As the light-emitting dopant, a fluorescent dopant (also referred to as a fluorescent compound) or a phosphorescent dopant (also referred to as a phosphorescent emitter, a phosphorescent compound, or a phosphorescent compound) can be used. From the viewpoint of obtaining an organic EL device having a high thickness, the light-emitting dopant used in the light-emitting layer or light-emitting unit of the organic EL device of the present invention (sometimes simply referred to as a light-emitting material) contains the above host compound at the same time. It is preferable to contain a phosphorescent dopant.

(Phosphorescent compound (phosphorescent dopant))
The phosphorescent compound (phosphorescent dopant) will be described.

  A phosphorescent compound is a compound in which light emission from an excited triplet is observed. Specifically, it is a compound that emits phosphorescence at room temperature (25 ° C.), and the phosphorescence quantum yield is 25 ° C. Although defined as 0.01 or more compounds, the preferred phosphorescence quantum yield is 0.1 or more.

  The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence emitting compound according to the present invention achieves the above phosphorescence quantum yield (0.01 or more) in any solvent. It only has to be done.

  There are two types of emission of phosphorescent compounds in principle. One is the recombination of carriers on the host compound to which carriers are transported to generate an excited state of the host compound. Energy transfer type to obtain light emission from the phosphorescent compound by transferring to the phosphorescent compound, the other is that the phosphorescent compound becomes a carrier trap, carrier recombination occurs on the phosphorescent compound, Examples include a carrier trap type in which light emission from a phosphorescent compound can be obtained.

  In any of the above cases, it is a condition that the excited state energy of the phosphorescent compound is lower than the excited state energy of the host compound.

  The phosphorescent compound can be appropriately selected from known compounds used for the light emitting layer of the organic EL device.

  The phosphorescent compound according to the present invention is preferably a complex compound containing a group 8-10 metal in the periodic table, more preferably an iridium compound (Ir complex), an osmium compound, or a platinum compound. (Platinum complex compounds) and rare earth complexes, with iridium compounds (Ir complexes) being most preferred among them.

  Specific examples of the compound used as the phosphorescent compound are shown below, but the present invention is not limited thereto. These compounds are described, for example, in Inorg. Chem. 40, 1704-1711, and the like.

  Hereinafter, although the specific example of the phosphorescence-emitting dopant which concerns on this invention is shown, this invention is not limited to these.

(Fluorescent dopant (also called fluorescent compound))
Fluorescent dopants (fluorescent compounds) include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, perylene dyes Examples thereof include dyes, stilbene dyes, polythiophene dyes, and rare earth complex phosphors.

  Next, an injection layer, a blocking layer, an electron transport layer, and the like used as a constituent layer of the organic EL element of the present invention will be described.

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

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

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

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

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

  The hole blocking layer has a function of an electron transport layer in a broad sense, and is made of a hole blocking material that has a function of transporting electrons and has a remarkably small ability to transport holes. The probability of recombination of electrons and holes can be improved by blocking.

  Moreover, the structure of the electron carrying layer mentioned later can be used as a hole-blocking layer concerning this invention as needed.

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

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

  In the present invention, when a plurality of light emitting layers having different light emission colors are provided, the light emitting layer having the shortest wavelength of light emission is preferably closest to the anode among all the light emitting layers. In this case, it is preferable to additionally provide a hole blocking layer between the shortest wave layer and the light emitting layer next to the anode next to the anode.

  Furthermore, it is preferable that 50% by mass or more of the compound contained in the hole blocking layer provided at the position has an ionization potential of 0.3 eV or more larger than the host compound of the shortest wave emitting layer.

  The ionization potential is defined by the energy required to emit an electron at the HOMO (highest occupied molecular orbital) level of the compound to the vacuum level, and can be obtained by the following method, for example.

  (1) Using Gaussian 98 (Gaussian 98, Revision A.11.4, MJ Frisch, et al, Gaussian, Inc., Pittsburgh PA, 2002.), a molecular orbital calculation software manufactured by Gaussian, USA The ionization potential can be obtained as a value obtained by rounding off the second decimal place of the value (eV unit converted value) calculated by performing structural optimization using B3LYP / 6-31G *. This calculation value is effective because the correlation between the calculation value obtained by this method and the experimental value is high.

  (2) The ionization potential can also be obtained by a method of directly measuring by photoelectron spectroscopy. For example, a method known as ultraviolet photoelectron spectroscopy can be suitably used by using a low energy electron spectrometer “Model AC-1” manufactured by Riken Keiki Co., Ltd.

  On the other hand, the electron blocking layer has a function of a hole transport layer in a broad sense, and is made of a material that has a function of transporting holes and has an extremely small ability to transport electrons, and transports electrons while transporting holes. By blocking, the recombination probability of electrons and holes can be improved.

  Moreover, the structure of the positive hole transport layer mentioned later can be used as an electron blocking layer as needed. The film thickness of the hole blocking layer and the electron transport layer according to the present invention is preferably 3 nm to 100 nm, and more preferably 5 nm to 30 nm.

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

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

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

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

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used. In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material.

  JP-A-11-251067, J. Org. Huang et. al. A so-called p-type hole transport material as described in a book (Applied Physics Letters 80 (2002), p. 139) can also be used. Furthermore, the organic EL element material of the present invention containing a polymerizable compound described later or a polymer compound having a structural unit derived from the polymerizable compound can be used, and the above materials may be used in combination.

  Hereinafter, representative specific examples of the hole transport material according to the present invention are shown, but the present invention is not limited thereto.

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

  Alternatively, a hole transport layer having a high p property doped with impurities can be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, 2001-102175, J. Pat. Appl. Phys. 95, 5773 (2004), and the like.

  In the present invention, it is preferable to use a hole transport layer having such a high p property because a device with lower power consumption can be produced.

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

  Conventionally, in the case of a single electron transport layer and a plurality of layers, an electron transport material (also serving as a hole blocking material) used for an electron transport layer adjacent to the light emitting layer on the cathode side is injected from the cathode. Any material may be used as long as it has a function of transferring electrons to the light-emitting layer, and any material can be selected from conventionally known compounds.

  Examples include nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives, and the like.

  Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum Tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), and the like, 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 the electron transport material.

  In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transporting material. In addition, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and an inorganic semiconductor such as n-type-Si, n-type-SiC, etc. as in the case of the hole injection layer and the hole transport layer. Can also be used as an electron transporting material.

  Hereinafter, although the specific example of the electron transport material which concerns on this invention is shown, this invention is not limited to these.

  The electron transport layer can be formed by thinning the electron transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method.

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

  Further, an electron transport layer having a high n property doped with impurities can also be used. Examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.

  In the present invention, it is preferable to use an electron transport layer having such a high n property because an element with lower power consumption can be manufactured.

"anode"
As the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used.

Specific examples of such electrode materials include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO.

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

  Or when using the substance which can be apply | coated like an organic electroconductivity compound, wet film-forming methods, such as a printing system and a coating system, can also be used.

  When light emission is extracted from the anode, it is desirable that the transmittance be greater than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 nm to 1000 nm, preferably 10 nm to 200 nm.

"cathode"
On the other hand, as the cathode, a material having a low work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like.

Among these, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred. The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. Alternatively, a metal foil film formed by coating a dispersion of metal nanoparticles such as silver nano ink and then heating and baking may be used.

  The sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 nm to 200 nm. In order to transmit the emitted light, if either one of the anode or the cathode of the organic EL element is transparent or translucent, the light emission luminance is improved, which is convenient.

  Moreover, after producing the said metal by the film thickness of 1 nm-20 nm to a cathode, the transparent or semi-transparent cathode can be produced by producing the electroconductive transparent material quoted by description of the anode on it, By applying this, an element in which both the anode and the cathode are transmissive can be manufactured.

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

  Examples of the transparent support substrate preferably used include glass, quartz, and a transparent resin film. A particularly preferable support substrate is a resin film capable of giving flexibility to the organic EL element.

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

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 ml / (m ² · 24 h · MPa) or less and a water vapor permeability of 10 ⁻⁵ g / (m ² · 24 h) or less is preferable.

  As a material for forming the barrier film, any material may be used as long as it has a function of suppressing entry of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like can be used. Further, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and organic material layers.

  Although there is no restriction | limiting in particular about the lamination | stacking order of an inorganic layer and an organic layer, It is preferable to laminate | stack both alternately several times.

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

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

  The external extraction efficiency at room temperature of light emission of the organic EL device of the present invention is preferably 1% or more, more preferably 5% or more.

  Here, the external extraction quantum efficiency (%) = the number of photons emitted to the outside of the organic EL element / the number of electrons sent to the organic EL element × 100.

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

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

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

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

In the present invention, a polymer film and a metal film can be preferably used because the element can be thinned. Furthermore, the polymer film has a oxygen permeability measured by a method according to JIS K 7126-1987 of 1 × 10 ⁻³ ml / (m ² · 24 h · MPa) or less, and a method according to JIS K 7129-1992. It is preferable that the water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) measured in (1) is 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-component mixing), such as an epoxy type, can be mentioned. Moreover, hot-melt type polyamide, polyester, and polyolefin can be mentioned. Moreover, a cationic curing type ultraviolet curing epoxy resin adhesive can be mentioned.

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

  It is also preferable to form an inorganic or organic layer as a sealing film by coating the electrode and the organic layer on the outer side of the electrode facing the support substrate with the organic layer interposed therebetween, and in contact with the support substrate. Can be. In this case, the material for forming the film may be any material that has a function of suppressing intrusion of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like may be used. it can. Further, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of organic materials.

  The method for forming these films is not particularly limited. For example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster-ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma A polymerization method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.

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

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

《Protective film, protective plate》
In order to increase the mechanical strength of the element, a protective film or a protective plate may be provided on the outer side of the sealing film on the side facing the support substrate with the organic layer interposed therebetween or on the sealing film.

  In particular, when the sealing is performed by the sealing film, the mechanical strength is not necessarily high, and thus it is preferable to provide such a protective film and a protective plate. As a material that can be used for this, the same glass plate, polymer plate / film, metal plate / film, and the like used for the sealing can be used, but the polymer film is light and thin. Is preferably used.

《Light extraction》
The organic EL element emits light inside a layer having a refractive index higher than that of air (refractive index is about 1.7 to 2.1) and can extract only about 15% to 20% of the light generated in the light emitting layer. It is generally said.

  This is because light incident on the interface (interface between the transparent substrate and air) at an angle θ greater than the critical angle causes total reflection and cannot be taken out of the device, or between the transparent electrode or light emitting layer and the transparent substrate. This is because the light is totally reflected between the light and the light is guided through the transparent electrode or the light emitting layer, and as a result, the light escapes in the direction of the element side surface.

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

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

  By combining these means, it is possible to obtain an element having higher luminance or durability.

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

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

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

  The method of introducing a diffraction grating into an interface or any medium that causes total reflection is characterized by a high effect of improving light extraction efficiency.

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

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

  However, by making the refractive index distribution a two-dimensional distribution, light traveling in all directions is diffracted, and light extraction efficiency is increased.

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

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

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

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

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

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

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

<Insolubilization>
In the organic EL device having a multi-unit structure according to the wet process of the present invention, there is an inherent problem that does not occur in the production by a dry process typified by a vacuum deposition method. The problem is that damage occurs. Many inventions have been made so far regarding the lamination method by the wet process. For example, the upper layer material is dissolved in a solvent outside the solubility range of the solubility parameter of the lower layer main material to disturb the lower layer thin film surface. A technique for laminating the film without disposing it is disclosed (for example, JP-A-2002-299061). In the present invention, such a known technique can be used when forming a multi-unit structure, but it is preferable to use a positive insolubilization technique as described below.

  The insolubilization used in the present invention refers to changing to an inert state with respect to a test solvent to be described later by performing the insolubilization treatment described below after film formation by a coating process.

The insolubilization process in the present invention will be described.
(1) Inhibition of Solvation Dissolution refers to a phenomenon in which a solute is solvated and diffuses into the solvent. Here, insolubilization is achieved by suppressing solvation or suppressing diffusion. Although the specific example of the insolubilization processing method is shown below, this invention is not limited to these.

  1. Use of high molecular weight material or high molecular weight polymer material: Decreasing the proportion of solvation, suppressing solvation and reducing solute diffusivity (mobility) Do suppression. The high molecular weight material in the present invention is an aromatic condensed ring derivative or heteroaromatic condensed ring derivative having a molecular weight of 800 or more and 1500 or less, more preferably an aromatic condensed ring derivative or heteroaromatic condensed ring derivative having a molecular weight of 800 or more and 1200 or less. It is. Examples of the polymer material include vinyl polymers having a number average molecular weight of 10,000 to 1,000,000, polyesters, polyamides, polyethers, polysulfides, polyimides, and polyarylenes.

2. Film surface modification: surface modification treatment by electron beam, ultraviolet ray, corona, plasma, etc., Macromolecules 1996, 29, 1229-1234, or DIC Technical Review No. By controlling surface free energy using surface localization of substituents described in 7/2001, etc., diffusion of the solvent into the solute is suppressed.
(2) Utilization of chemical changes to insoluble materials After application and film formation from solution, re-dissolution is impossible due to chemical or physical changes caused by internal or external stimuli such as heat, light, electromagnetic waves, etc. Put it in a state. Although the specific example of the insolubilization processing method is shown below, this invention is not limited to these.

  1. Cross-linking reaction: Using low molecular weight materials, high molecular weight materials, or multiple cross-linking groups (polysynthetic reactive groups) present in a polymer, after application / film formation, by heat, light, electromagnetic waves, etc. A method of insolubilizing by multidimensional crosslinking. A thermal / photopolymerization initiator or a crosslinking agent may be used in combination.

  Hereinafter, examples of the crosslinking group that can be used in the present invention include a partial structure represented by the general formula (100). Each crosslinking group may be used alone or in combination.

General formula (100)
L-P
L represents a simple bond or a divalent linking group, and P represents a polymerizable substituent represented by the following. Examples of the divalent linking group used in the present invention include an alkylene group, an alkenylene group, an arylene group, a heteroarylene group, —O—, —S—, —NR—, —CO—, —COO—, —NRCO—, It represents a divalent linking group selected from the group consisting of —SO ₂ — or a combination thereof. Here, R represents an alkyl group.

  In addition, * shows the coupling | bonding point with L.

In the above, in * -M (OR) _x By, R represents an alkyl group, x is an integer of 2 or more, and y substituents B are bonded so as to satisfy the valence of the metal M. The substituent is as described above. When a plurality of B are present, they may be different from each other.

  In addition, as a substituent used by this invention, including the said general formula (A)-(J), an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an alkylthio group, an aryl group, an aryloxy group, an arylthio group, Arylalkyl group, arylalkoxy group, arylalkylthio group, arylalkenyl group, arylalkynyl group, heteroaryl group, heteroaryl group, heteroaryloxy group, heteroarylthio group, heteroarylalkyl group, heteroarylalkoxy group, heteroaryl Alkylthio group, heteroarylalkenyl group, heteroarylalkynyl group, amino group, substituted amino group, silyl group, substituted silyl group, halogen atom, acyl group, acyloxy group, imine residue, amide group, acid imide group, monovalent Heterocyclic group, carboxy Group, substituted carboxyl group, a cyano group or a nitro group, halogenyl group and the like. An aryl group is an aromatic hydrocarbon in which one hydrogen atom is removed, and examples of aromatic hydrocarbons include aromatic monocyclic hydrocarbons, condensed polycyclic hydrocarbons, and a plurality of independent aromatics. Also included are those in which a group monocyclic hydrocarbon or condensed polycyclic hydrocarbon is bonded. Examples thereof include a phenyl group, a naphthyl group, an anthryl group, a biphenyl group, a fluorenyl group, and a binaphthyl group. A heteroaryl group is one obtained by removing one hydrogen atom from a heteroaromatic hydrocarbon. As the heteroaromatic hydrocarbon, the element constituting the aromatic hydrocarbon ring is 1 of carbon atoms. Refers to one or more atoms substituted with heteroatoms such as oxygen, sulfur, nitrogen, phosphorus, boron, heteroaromatic monocyclic hydrocarbons, heterocondensed polycyclic hydrocarbons, independent heteroaromatics Also included are monocyclic hydrocarbons or heterocondensed polycyclic hydrocarbons bonded together. Examples include pyridyl group, thiophenyl group, bipyridyl group, phenylpyridinyl group, carbazolyl group, azacarbazolyl group, imidazolyl group, dibenzofuranyl group, isoquinolyl group, dibenzophosphonyl group and the like.

  The bridging group represented by the general formula (100) can be used by substituting with any hydrogen atom of the material constituting the light emitting unit or the charge generation layer. The number of substitutions is 1 to 10, preferably 1 to 4, in the case of a non-polymer compound having no repeating unit, and in the case of a polymer compound having a repeating structure, the number of crosslinking groups per 10,000 number average molecular weight is 10,000. 1 to 100, preferably 1 to 10. For example, the number of crosslinkable groups in a polymer having a number average molecular weight of 50,000 is 5 to 500, preferably 5 to 50.

  Specific examples of the low molecular weight material, high molecular weight material, or high molecular polymer that can be used in the present invention will be given below, but the present invention is not limited thereto.

  Furthermore, specific examples of low molecular weight materials, high molecular weight materials, or high molecular polymers that can be used in the present invention will be given.

(3) Coating film formation of insoluble material Film formation of dispersion: An insoluble material dispersion liquid is produced by a method of making an insoluble material into a fine particle in a solvent dispersion method, or a method of adjusting by dispersion associated with the formation of an insoluble fine particle of a soluble precursor in a solvent. An insolubilized thin film can be produced by coating and film-forming this dispersion. The formation of insoluble fine particles of the soluble precursor can be formed by chemical change due to internal or external stimulation such as heat, light, electromagnetic waves, etc., after coating / film formation of the soluble precursor compound in a solvent.

  The solvent as used in the present invention is a name for a liquid that dissolves a solid or a liquid. However, when specifically described as a test solvent, aromatic hydrocarbons (toluene, chlorobenzene, pyridine), saturated hydrocarbons (cyclohexane, Decane, perfluorooctane), alcohols (isopropyl alcohol, hexafluoroisopropanol), ketones (methyl ethyl ketone, cyclohexanone), esters (butyl acetate, phenyl acetate), dichloroethane, tetrahydrofuran, acetonitrile. Inert state means i) change in film thickness due to UV absorption change, ii) change in state of light emitting layer due to change in PL (photoluminescence), iii) at least one item of rectification ratio satisfies a predetermined evaluation standard value Refers to the state.

<< Method for producing organic EL element >>
As an example of the method for producing the organic EL device of the present invention, a single light emitting unit comprising an anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer / cathode is prepared. A method for manufacturing the organic EL element will be described.

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

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

  As methods for forming each of these layers, there are a vapor deposition method and a coating process (spin coating method, casting method, ink jet method, printing method) as described above, but it is easy to obtain a uniform film and a pinhole is generated. In view of difficulty, etc., film formation by a coating method such as a spin coating method, an ink jet method, or a printing method is preferable in the present invention.

  In particular, the layer containing a compound having a carbazole ring as a partial structure according to the present invention, the compound having a polymerizable group, and a polymer of the compound is preferably formed by the above-described coating method. Is preferably a light emitting layer.

  Further, when the total number of layers (the constituent layers of the organic EL element) existing between the anode and the cathode is 100%, 50% or more of the total number of layers is preferably formed by a coating method. .

  For example, in the anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer / cathode mentioned as an example of the organic EL element, the hole injection layer In the case where the total number of layers / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer is 6, it is preferable that at least three layers are formed by a coating method.

  When forming the constituent layers of the organic EL element of the present invention by coating, examples of the liquid medium for dissolving or dispersing various organic EL materials used for coating include ketones such as methyl ethyl ketone and cyclohexano, and fatty acids such as ethyl acetate. Esters, halogenated hydrocarbons such as dichlorobenzene, aromatic hydrocarbons such as toluene, xylene, mesitylene and cyclohexylbenzene, aliphatic hydrocarbons such as cyclohexane, decalin and dodecane, organic solvents such as DMF and DMSO Can be used.

  Moreover, as a dispersion method, it can disperse | distribute by dispersion methods, such as an ultrasonic wave, high shear force dispersion | distribution, and media dispersion | distribution.

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

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

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

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

  In the organic EL element of the present invention, patterning may be performed by a metal mask, an ink jet printing method, or the like as needed during film formation.

  In the case of patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire layer of the device may be patterned. Can do.

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

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. = 0.33 ± 0.07 and Y = 0.33 ± 0.1.

<Display device>
The display device of the present invention will be described. The display device of the present invention comprises the organic EL element of the present invention.

  Although the display device of the present invention may be single color or multicolor, the multicolor display device will be described here. In the case of a multicolor display device, a shadow mask is provided only at the time of forming a light emitting layer, and a film can be formed on one surface by vapor deposition, casting, spin coating, ink jet, printing, or the like.

  In the case of patterning only the light emitting layer, the method is not limited. However, the vapor deposition method, the ink jet method, the spin coating method, and the printing method are preferable.

  The configuration of the organic EL element provided in the display device is selected from the above-described configuration examples of the organic EL element as necessary.

  Moreover, the manufacturing method of an organic EL element is as having shown to the one aspect | mode of manufacture of the organic EL element of said invention.

  In the case of applying a DC voltage to the obtained multicolor display device, light emission can be observed by applying a voltage of about 2V to 40V with the positive polarity of the anode and the negative polarity of the cathode. Further, even when a voltage is applied with the opposite polarity, no current flows and no light emission occurs. Further, when an AC voltage is applied, light is emitted only when the anode is in the + state and the cathode is in the-state. The alternating current waveform to be applied may be arbitrary.

  The multicolor display device can be used as a display device, a display, and various light emission sources. In a display device or display, full-color display is possible by using three types of organic EL elements of blue, red, and green light emission.

  Examples of the display device and display include a television, a personal computer, a mobile device, an AV device, a character broadcast display, and an information display in an automobile. In particular, it may be used as a display device for reproducing still images and moving images, and the driving method when used as a display device for reproducing moving images may be either a simple matrix (passive matrix) method or an active matrix method.

  Light sources include home lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, light sources for optical sensors, etc. The present invention is not limited to these examples.

  Hereinafter, an example of a display device having the organic EL element of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic view showing an example of a display device composed of organic EL elements. It is a schematic diagram of a display such as a mobile phone that displays image information by light emission of an organic EL element.

  The display 1 includes a display unit A having a plurality of pixels, a control unit B that performs image scanning of the display unit A based on image information, and the like.

  The control unit B is electrically connected to the display unit A, and sends a scanning signal and an image data signal to each of a plurality of pixels based on image information from the outside, and the pixels for each scanning line respond to the image data signal by the scanning signal. The image information is sequentially emitted to scan the image and display the image information on the display unit A.

  FIG. 2 is a schematic diagram of the display unit A.

  The display unit A includes a wiring unit including a plurality of scanning lines 5 and data lines 6, a plurality of pixels 3 and the like on a substrate. The main members of the display unit A will be described below.

  In the figure, the light emitted from the pixel 3 is extracted in the direction of the white arrow (downward).

  The scanning line 5 and the plurality of data lines 6 in the wiring portion are each made of a conductive material, and the scanning lines 5 and the data lines 6 are orthogonal to each other in a grid pattern and are connected to the pixels 3 at the orthogonal positions (details are illustrated). Not)

  When a scanning signal is applied from the scanning line 5, the pixel 3 receives an image data signal from the data line 6 and emits light according to the received image data.

  Full-color display is possible by appropriately arranging pixels in the red region, the green region, and the blue region on the same substrate.

  Next, the light emission process of the pixel will be described.

  FIG. 3 is a schematic diagram of a pixel.

  The pixel includes an organic EL element 10, a switching transistor 11, a driving transistor 12, a capacitor 13, and the like. A full color display can be performed by using red, green, and blue light emitting organic EL elements as the organic EL elements 10 in a plurality of pixels, and juxtaposing them on the same substrate.

  In FIG. 3, an image data signal is applied from the control unit B to the drain of the switching transistor 11 through the data line 6. When a scanning signal is applied from the control unit B to the gate of the switching transistor 11 via the scanning line 5, the driving of the switching transistor 11 is turned on, and the image data signal applied to the drain is supplied to the capacitor 13 and the driving transistor 12. Is transmitted to the gate.

  By transmitting the image data signal, the capacitor 13 is charged according to the potential of the image data signal, and the drive of the drive transistor 12 is turned on. The drive transistor 12 has a drain connected to the power supply line 7 and a source connected to the electrode of the organic EL element 10, and the power supply line 7 connects to the organic EL element 10 according to the potential of the image data signal applied to the gate. Current is supplied.

  When the scanning signal is moved to the next scanning line 5 by the sequential scanning of the control unit B, the driving of the switching transistor 11 is turned off. However, even if the driving of the switching transistor 11 is turned off, the capacitor 13 maintains the potential of the charged image data signal, so that the driving of the driving transistor 12 is kept on and the next scanning signal is applied. Until then, the light emission of the organic EL element 10 continues. When the scanning signal is next applied by sequential scanning, the driving transistor 12 is driven according to the potential of the next image data signal synchronized with the scanning signal, and the organic EL element 10 emits light.

  That is, the light emission of the organic EL element 10 is performed by providing the switching transistor 11 and the drive transistor 12 which are active elements with respect to the organic EL element 10 of each of the plurality of pixels, and light emission of the organic EL element 10 of each of the plurality of pixels 3. It is carried out. Such a light emitting method is called an active matrix method.

  Here, the light emission of the organic EL element 10 may be light emission of a plurality of gradations by a multi-value image data signal having a plurality of gradation potentials, or by turning on / off a predetermined light emission amount by a binary image data signal. Good. The potential of the capacitor 13 may be maintained until the next scanning signal is applied, or may be discharged immediately before the next scanning signal is applied.

  In the present invention, not only the active matrix method described above, but also a passive matrix light emission drive in which the organic EL element emits light according to the data signal only when the scanning signal is scanned.

  FIG. 4 is a schematic diagram of a passive matrix display device. In FIG. 4, a plurality of scanning lines 5 and a plurality of image data lines 6 are provided in a lattice shape so as to face each other with the pixel 3 interposed therebetween.

  When the scanning signal of the scanning line 5 is applied by sequential scanning, the pixels 3 connected to the applied scanning line 5 emit light according to the image data signal.

  In the passive matrix system, the pixel 3 has no active element, and the manufacturing cost can be reduced.

《Lighting device》
The lighting device of the present invention will be described. The illuminating device of this invention has the said organic EL element.

  The organic EL element of the present invention may be used as an organic EL element having a resonator structure. The purpose of use of the organic EL element having such a resonator structure is as follows. The light source of a machine, the light source of an optical communication processing machine, the light source of a photosensor, etc. are mentioned, However, It is not limited to these. Moreover, you may use for the said use by making a laser oscillation.

  Further, the organic EL element of the present invention may be used as a kind of lamp for illumination or exposure light source, a projection device for projecting an image, or a display for directly viewing a still image or a moving image. It may be used as a device (display).

  The driving method when used as a display device for moving image reproduction may be either a simple matrix (passive matrix) method or an active matrix method. Alternatively, a full-color display device can be manufactured by using two or more organic EL elements of the present invention having different emission colors.

  The organic EL material of the present invention can be applied as an illumination device to an organic EL element that emits substantially white light. A plurality of light emitting colors are simultaneously emitted by a plurality of light emitting materials to obtain white light emission by color mixing. The combination of a plurality of emission colors may include three emission maximum wavelengths of the three primary colors of blue, green, and blue, or two using the relationship of complementary colors such as blue and yellow, blue green and orange, etc. The thing containing the light emission maximum wavelength may be used.

  In addition, a combination of light emitting materials for obtaining a plurality of emission colors is a combination of a plurality of phosphorescent or fluorescent materials, a light emitting material that emits fluorescence or phosphorescence, and light from the light emitting material as excitation light. Any of those combined with a dye material that emits light may be used, but in the white organic EL device according to the present invention, only a combination of a plurality of light-emitting dopants may be mixed.

  It is only necessary to provide a mask only when forming a light emitting layer, a hole transport layer, an electron transport layer, etc., and simply arrange them separately by coating with the mask. Since other layers are common, patterning of the mask or the like is not necessary. In addition, for example, an electrode film can be formed by a vapor deposition method, a cast method, a spin coating method, an ink jet method, a printing method, or the like, and productivity is also improved.

  According to this method, unlike a white organic EL device in which light emitting elements of a plurality of colors are arranged in parallel in an array, the elements themselves are luminescent white.

  There is no restriction | limiting in particular as a luminescent material used for a light emitting layer, For example, if it is a backlight in a liquid crystal display element, the metal complex which concerns on this invention so that it may suit the wavelength range corresponding to CF (color filter) characteristic, Any one of known luminescent materials may be selected and combined to whiten.

<< One Embodiment of Lighting Device of the Present Invention >>
One aspect of the lighting device of the present invention that includes the organic EL element of the present invention will be described.

  The non-light emitting surface of the organic EL device of the present invention is covered with a glass case, a glass substrate having a thickness of 300 μm is used as a sealing substrate, and an epoxy-based photocurable adhesive (LUX TRACK manufactured by Toagosei Co., Ltd.) is used as a sealing material. LC0629B) is applied, and this is overlaid on the cathode and brought into close contact with the transparent support substrate, irradiated with UV light from the glass substrate side, cured and sealed, and an illumination device as shown in FIGS. Can be formed.

  FIG. 5 shows a schematic diagram of a lighting device, and the organic EL element 201 of the present invention is covered with a glass cover 202 (in addition, the sealing operation with the glass cover is to bring the organic EL element 201 into contact with the atmosphere. And a glove box under a nitrogen atmosphere (in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more).

  6 shows a cross-sectional view of the lighting device. In FIG. 6, reference numeral 205 denotes a cathode, 206 denotes an organic EL layer, and 207 denotes a glass substrate with a transparent electrode. The glass cover 202 is filled with nitrogen gas 208 and a water catching agent 209 is provided.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

Example 1
<Two-layer CGL consisting of n-type layer / p-type layer>
<First unit>
After patterning on a substrate (NH-Techno Glass NA-45) formed by depositing 100 nm of ITO (indium tin oxide) on a 100 mm × 100 mm × 1.1 mm glass substrate as an anode, this ITO transparent electrode was provided. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  On this transparent support substrate, a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water by a slit coating method. After film formation, the film was dried at 200 ° C. for 1 hour to provide a first hole transport layer having a film thickness of 30 nm.

  In the following production from the first hole transport layer, an organic EL device was produced in a glove box controlled to have a moisture / oxygen concentration of 1 ppm or less.

  A slit of a chlorobenzene solution of Poly-N, N′-bis (4-butylphenyl) -N, N′-bis (phenyl) benzidine (manufactured by American Dye Source, ADS-254) on the first hole transport layer A film was formed by a coating method. It heat-dried at 150 degreeC for 1 hour, and provided the 2nd hole transport layer with a film thickness of 40 nm.

  On this second hole transport layer, a butyl acetate solution of OC-25, D-1, and D-20 (each ratio is 83.5 w mass%: 16 mass%: 0.5 mass%) is obtained by a slit coating method. A film was formed. Heat-dried at 120 ° C. for 1 hour to provide a light-emitting layer having a thickness of 40 nm.

On this light emitting layer, a 1,1,1-3,3,3-hexafluoroisopropanol solution of OC-107 was formed by a slit coating method, and after the film formation, a low-pressure mercury lamp (15 mW / cm ² ) was applied for 30. The polymerized group of OC-107 was photocured by UV irradiation at 130 ° C. for 2 seconds to provide an insolubilized electron transport layer having a thickness of 20 nm.

  Next, a charge generation layer was formed on the electron transport layer by one of the following production methods.

<Charge generation layer>
<Method 1 for creating charge generation layer>
A chlorobenzene solution of CGL (n-type) 1 and CGL (n-type) 2 (described in the table) is formed on this electron transport layer by a slit coating method, and a low-pressure mercury lamp (15 mW / cm ² ) is formed after the film formation. By UV irradiation at 130 ° C. for 30 seconds, the polymerizable group of the compound was photocured to provide an insolubilized n-type layer (CGL) having a thickness of 20 nm.

Further, a chlorobenzene solution of CGL (p-type) 1 and CGL (p-type) 2 (described in the table) was formed on the n-type layer (CGL) by a slit coating method, and after the film formation, a low-pressure mercury lamp (15 mW) / Cm ² ) for 30 seconds at 130 ° C. for UV irradiation to photocur the polymerizable group of the compound and provide a 20 nm thick insolubilized p-type layer (CGL).

  In the above production, in the layer of CGL (n-type) or CGL (p-type) in the charge generation layer, (:) in the table is CGL (n-type) 1: CGL (n-type) 2 and CGL (p-type) 1: CGL (p-type) 2 mixed material layer, and (/) indicates a layer made of CGL (n-type) and a layer made of CGL (p-type). It shows that it laminated | stacked. The ratio of each material when mixed in the case of two components was all set to (50% by mass: 50% by mass).

<Second unit>
Furthermore, a chlorobenzene solution of ADS-254 was formed on the p-type layer (CGL) by a slit coating method. It heat-dried at 150 degreeC for 1 hour, and provided the 2nd hole transport layer with a film thickness of 40 nm.

  On this second hole transport layer, a butyl acetate solution of OC-25, D-1, D-20 (each ratio is 83.5% by mass: 16% by mass: 0.5% by mass) is obtained by slit coating. A film was formed. Heat-dried at 120 ° C. for 1 hour to provide a light-emitting layer having a thickness of 40 nm.

On this light emitting layer, a 1,1,1-3,3,3-hexafluoroisopropanol solution of OC-107 was formed by a slit coating method, and after the film formation, a low-pressure mercury lamp (15 mW / cm ² ) was applied for 30. The polymerized group of OC-107 was photocured by UV irradiation at 130 ° C. for 2 seconds to provide an insolubilized electron transport layer having a thickness of 20 nm.

This was attached to a vacuum deposition apparatus, and the vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa. Subsequently, 1.0 nm of cesium fluoride was vapor-deposited as an electron injection layer, and 110 nm of aluminum was vapor-deposited as a cathode, and the organic EL element which has two light emission units and one CGL was manufactured.

  Organic EL elements were produced by changing the materials of CGL (n-type) and CGL (p-type) as shown in the table.

  Further, a comparative element was prepared as follows (Comparative Example 1).

  After patterning on a substrate (NH-Techno Glass NA-45) formed by depositing 100 nm of ITO (indium tin oxide) on a 100 mm × 100 mm × 1.1 mm glass substrate as an anode, this ITO transparent electrode was provided. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  On this transparent support substrate, a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water by a slit coating method. After the film formation, the film was dried at 200 ° C. for 1 hour to provide a first hole transport layer having a thickness of 30 nm.

  In the following production from the first hole transport layer, an organic EL device was produced in a glove box controlled to have a moisture / oxygen concentration of 1 ppm or less.

  A chlorobenzene solution of ADS-254 was formed on the first hole transport layer by a slit coating method. It heat-dried at 150 degreeC for 1 hour, and provided the 2nd hole transport layer with a film thickness of 40 nm.

  On this second hole transport layer, a butyl acetate solution of OC-25, D-1, D-20 (each ratio is 83.5% by mass: 16% by mass: 0.5% by mass) is slit coated. Was formed. Heat-dried at 120 ° C. for 1 hour to provide a light-emitting layer having a thickness of 40 nm.

On this light emitting layer, a 1,1,1-3,3,3-hexafluoroisopropanol solution of OC-107 was formed by a slit coating method, and after the film formation, a low-pressure mercury lamp (15 mW / cm ² ) was applied for 30. The polymerized group of OC-107 was photocured by UV irradiation at 130 ° C. for 2 seconds to provide an insolubilized electron transport layer having a thickness of 20 nm.

<Creation method of charge generation layer (evaporation method)>
Then, this was attached to the vacuum evaporation apparatus and the vacuum chamber was pressure-reduced to 4 * 10 <^-4> Pa.

  Subsequently, a BCP: Li co-deposited film (99: 1 vol%) was vacuum-deposited by 20 nm to form an n-type layer. Li deposition used a Saesgetter Li source boat.

  On the n-type layer (CGL), m-MTDATA: F4-TCNQ (AG-6) was co-deposited (90:10 vol%) by vacuum deposition to a thickness of 10 nm to form a p-type layer.

  Furthermore, 40 nm of α-NPD (DAm-1) was deposited as a second hole transport layer.

  OC-25, D-1, and D-20 (each ratio is 83.5 mass%: 16 mass%: 0.5 mass%) are vapor-deposited on α-NPD (DAm-1), and the second 40 nm is deposited. A light emitting layer was obtained.

  Furthermore, OC-105 was formed by 20 nm vapor deposition on the 2nd light emitting layer.

  Subsequently, cesium fluoride 1.0 nm was vapor-deposited as an electron injection layer, and aluminum 110 nm was vapor-deposited as a cathode, and the organic EL element (comparative example) which has two light emission units and one CGL was manufactured.

  In the present invention, there is almost no difference in performance as an organic EL between the vapor-deposited light-emitting unit and the light-emitting unit produced by coating, and the effects in the present invention are as shown in the following table. is not.

  Further, as Comparative Example 2, an attempt was made to create by coating using the charge generation layer material produced by the vapor deposition method, but the coating could not be performed.

  The element was evaluated as follows.

<Evaluation>
When evaluating each organic EL element obtained, the non-light emitting surface of each organic EL element after production was covered with a glass case, a glass substrate having a thickness of 300 μm was used as a sealing substrate, and an epoxy was used as a sealing material around. Applying a photo-curing adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.), stacking it on the cathode and bringing it into close contact with the transparent support substrate, irradiating it with UV light from the glass substrate side, curing it, Sealing was performed to form an illumination device as shown in FIGS. 5 and 6, and external extraction quantum efficiency, driving voltage, initial luminance change, and voltage increase during driving were evaluated. Moreover, the conditions in each evaluation item are shown below.

Initial luminance change ΔL;
In constant current driving at an initial luminance of 3000 cd / m ² , the luminance change after 100 hours is expressed as follows.

ΔL = luminance after 100 hours / initial luminance (3000 cd / m ² ) × 100
The change in luminance (ΔL) in the comparative element was taken as 100, and the change in luminance (ΔL) in each element was expressed as a relative value.

Voltage rise ΔV during driving;
Evaluation was based on the ratio of the voltage at constant current driving at an initial luminance of 3000 cd / m ² and the voltage at half luminance.

ΔV = voltage at half brightness / initial voltage × 100
《External extraction quantum efficiency (EQE)》
For the organic EL element, the external extraction quantum efficiency (%) was measured when a constant current of ^2.5 mA / cm ² was applied at 23 ° C. in a dry nitrogen gas atmosphere. For the measurement, a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing) was used.

<< Drive voltage (V) >>
With respect to the organic EL element, a voltage was measured when a ^2.5 mA / cm ² constant current was applied at 23 ° C. in a dry nitrogen gas atmosphere. Relative evaluation was performed when the value in Comparative Example 1 was set to 100.

  The obtained results are shown in Tables 1-10.

  The device of the present invention has a large external extraction quantum efficiency, a low driving voltage, and a small voltage increase due to driving. It can also be seen from the initial luminance change that the reduction in luminance is not as great as the comparison, and the element of the present invention is superior.

Example 2
<Double-layer CGL consisting of n-type layer / p-type layer by vapor deposition>
<First unit>
After patterning on a substrate (NH-Techno Glass NA-45) formed by depositing 100 nm of ITO (indium tin oxide) on a 100 mm × 100 mm × 1.1 mm glass substrate as an anode, this ITO transparent electrode was provided. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  A solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, manufactured by Bayer, Baytron P Al 4083) to 70% with pure water on a transparent support substrate was formed by a slit coat method. After film-forming, it dried at 200 degreeC for 1 hour, and provided the 1st positive hole transport layer with a film thickness of 30 nm.

This transparent support substrate is fixed to a substrate holder of a commercially available vacuum evaporation apparatus, while 200 mg of α-NPD (DAm-1) is placed in a molybdenum resistance heating boat, and H— is added as a host compound to another molybdenum resistance heating boat. 1 200 mg, 200 mg of BAlq in another molybdenum resistance heating boat, 100 mg of D-1 and 100 mg of D-21 as luminescent dopant compounds in another molybdenum resistance heating boat, and another molybdenum resistance 200 mg of Alq ₃ was placed in a heating boat and attached to a vacuum deposition apparatus.

Next, after reducing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing α-NPD was heated by heating, and deposited on the transparent support substrate at a deposition rate of 0.1 nm / sec. The hole transport layer was provided.

  Further, the heating boat containing H-1, D-1, and D-21 was energized and heated, and the holes were deposited at a deposition rate of 0.2 nm / second, 0.012 nm / second, and 0.0012 nm / second, respectively. A 40 nm-thick luminescent layer was provided by co-evaporation on the transport layer. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Further, the heating boat containing BAlq was energized and heated, and was deposited on the light emitting layer at a deposition rate of 0.1 nm / second to provide a 10 nm thick hole blocking layer.

In addition, the heating boat containing Alq ₃ is further energized and heated, and deposited on the hole blocking layer at a deposition rate of 0.1 nm / second to further provide an electron transport layer having a thickness of 40 nm. It was. In addition, the substrate temperature at the time of vapor deposition was room temperature.

(CGL)
Subsequently, a BCP: Li co-deposited film (99: 1 vol%) was vacuum-deposited by 20 nm to form an n-type layer. Li deposition used a Saesgetter Li source boat.

  On the n-type layer (CGL), m-MTDATA: F4-TCNQ was co-deposited (90:10 vol%) by vacuum deposition to a thickness of 10 nm to form a p-type layer.

<Second unit>
Next, the heating boat containing α-NPD was energized and heated, and deposited on a transparent support substrate at a deposition rate of 0.1 nm / second to provide a hole transport layer having a thickness of 40 nm.

  Further, the heating boat containing H-1, D-1, and D-21 was energized and heated, and the holes were deposited at a deposition rate of 0.2 nm / second, 0.012 nm / second, and 0.0012 nm / second, respectively. A 40 nm-thick luminescent layer was provided by co-evaporation on the transport layer. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Further, the heating boat containing BAlq was energized and heated, and was deposited on the light emitting layer at a deposition rate of 0.1 nm / second to provide a 10 nm thick hole blocking layer.

In addition, the heating boat containing Alq ₃ is further energized and heated, and deposited on the hole blocking layer at a deposition rate of 0.1 nm / second to further provide an electron transport layer having a thickness of 40 nm. It was.

  Subsequently, 1.0 nm of cesium fluoride was vapor-deposited as an electron injection layer, and 110 nm of aluminum was vapor-deposited as a cathode, and the organic EL element which has two light emission units and one CGL was manufactured.

  Next, in the organic EL element, only (CGL) is replaced with the co-deposited film of CGL (n-type) 1 and CGL (n-type) 2 (respectively described in the table) instead of the n-type BCP: Li co-deposited film. In addition, the p-type layer was changed to a co-deposited film of CGL (p-type) 1 and CGL (p-type) 2 instead of the co-deposited film of m-MTDATA: F4-TCNQ (this is also described in the table). Similarly, organic EL elements shown in each table were prepared.

  In the charge generation layer, (:) indicates that the n-type layer or the p-type layer is made of a mixture of a plurality of materials, and (/) indicates a layer made of CGL (n-type) and CGL (p-type). It shows that the layer which consists of was laminated | stacked. Moreover, the ratio of each material when it mixed was set to (50 mass%: 50 mass%).

  Each organic EL element was evaluated. As the evaluation method, the same method as in Example 1 was used.

  The results are shown in Tables 11-24.

CGL using the compound of the reference example showed a preferable result even in preparation by vapor deposition.

DESCRIPTION OF SYMBOLS 1 Display 3 Pixel 5 Scan line 6 Data line 7 Power supply line 10 Organic EL element 11 Switching transistor 12 Drive transistor 13 Capacitor A Display part B Control part 101 Glass substrate 102 ITO transparent electrode 103 Partition 104 104 Hole injection layer 105B, 105G, 105R Luminescent layer 207 Glass substrate with transparent electrode 206 Organic EL layer 205 Cathode 202 Glass cover 208 Nitrogen gas 209 Water catching agent

Claims (3)

In an organic electroluminescence device having a charge generation layer that generates holes and electrons by applying an electric field between a plurality of light emitting units,
The charge generation layer includes an organic donor and an organic acceptor,
Organic donor or organic acceptor, compound or an organic electroluminescence device in which the derivatives are characterized polymer der Rukoto that multidimensional crosslinking having a partial structure represented by the following general formula (A).

(Wherein X ₁ , X ₂ , X ₃ and X ₄ are each independently N or CR, R represents a hydrogen atom, an alkyl group, an alkoxy group, an aryl group or a heteroaryl group. M is H ₂ , the metal atom represented by .M representing a metal atom, T iO or VO _{is, Co, Fe, Mg, Li} 2, Ru, Zn, Cu, Ni, Na 2, Cs 2 or a Sb.) The organic electroluminescence device according to claim 1, which emits phosphorescence. Lighting device characterized by using the organic electroluminescent element of any one of claims 1 or 2.

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