JP2010021336A - Organic electroluminescence device, illuminator, and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL element material which has high emission efficiency and reduced in voltage, as well as to provide an organic EL element, an illuminator, and a display device which use the material. <P>SOLUTION: In an organic electroluminescence device has multiple organic layers, including a light-emitting layer sandwiched in between a positive electrode and a negative electrode, at least one of the organic layers contains thiocarbasole, having a specific structure and a carbasole compound. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an organic electroluminescence element, a lighting device, and a display device. More specifically, the present invention relates to an organic EL element material that exhibits high luminous efficiency and has a low voltage, and an organic EL element using the same.

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

  On the other hand, an organic EL element has a configuration in which a light emitting layer containing a compound that emits light is sandwiched between a cathode and an anode, and injects electrons and holes into the light emitting layer to recombine excitons. It is an element that emits light by utilizing light emission (fluorescence / phosphorescence) when the exciton is deactivated. Between the electrodes, the thickness is only about 0.1 μm, the light emission can be performed at a relatively low voltage of about several V to several tens V, and the viewing angle because of the self-luminous type. Therefore, it is attracting attention as a next-generation flat display and illumination from the viewpoint of space saving, portability, etc.

  Currently, in order to realize low voltage, high luminous efficiency and high luminance, organic EL elements are composed of a plurality of organic layers having functions other than light emission, in addition to a light emitting layer, such as a hole transport layer and an electron transport layer. In addition, it is known that the light emitting layer emits light more efficiently by containing a small amount of a dopant compound in the host compound. As the dopant molecules, fluorescent dopants represented by quinacridone derivatives (see, for example, Patent Document 1) and phosphorescent dopants represented by iridium (III) tris (2-phenylpyridine) are known and have high light emission. Research has been actively conducted on phosphorescent dopants having efficiency and host molecules for efficiently emitting phosphorescent dopants.

Further, as a method for producing an organic EL element, a vapor deposition method and a coating method (wet method) are known, which can be easily applied to increase the area of the organic EL element and can be produced at a low cost in the future. In recent years, research on organic EL device production by a coating method has been extensively conducted. (For example, see Patent Document 2 and Patent Document 3.)
JP-A-3-255190 JP 2008-13700 A International publication 07/198116 pamphlet

  An object of the present invention is to provide an organic EL element, a lighting device, and a display device that are excellent in high temperature durability, exhibit high light emission efficiency, and have a low voltage.

  The above object of the present invention has been achieved by the following constitution.

1. In an organic electroluminescence device having a plurality of organic layers including a light emitting layer sandwiched between an anode and a cathode,
At least 1 layer of this organic layer contains the compound represented by following General formula (1), The organic electroluminescent element characterized by the above-mentioned.

[Wherein, R _{11 to} R ₁₈ , R _{21 to} R ₂₈ , R _{31 to} R ₃₆ and R _{40 to} R ₄₈ each represent a hydrogen atom or a substituent. X ₁ represents a simple bond or a linking group. However, at least one of R _{11 to} R ₁₈ and at least one of R _{21 to} R ₂₈ are each used for connection with any one of R _{31 to} R ₃₆ , and R _{11 to} R ₁₈ , R _{21 to} R are used. ₂₈ and at least one of R _{31 to} R ₃₆ and at least one of R _{40 to} R ₄₈ are used for connection with X ₁ . n represents an integer of 1 or more, and when n is 2 or more, the bonding positions may be the same or different. m represents an integer of 0 or more. When m is 2 or more, X ₁ may be the same or different. M represents an integer of 1 or more, and when M is 2 or more, X ₁ may be the same or different. ]
2. 2. The organic electroluminescence device according to 1 above, wherein in the general formula (1), any two of R _{31 to} R ₃₆ are bonded to R ₁₆ and R ₂₃ .

3. 2. The organic electroluminescence device according to 1 above, wherein in the general formula (1), R ₃₁ and R ₃₃ are bonded to R ₁₆ and R ₂₃ .

  4). The compound represented by the general formula (1) is represented by the following general formula (2), general formula (3), or general formula (4): The organic electroluminescent element of description.

_Wherein, R 11 _{to R 18} and _R 21 _{to R 28} are each the same meaning as _R 11 _{to R 18} and _R 21 _{to R 28} in the general formula (1). ]
5). 5. The organic electroluminescent element according to any one of 1 to 4, wherein at least one of the organic layers is formed by a wet method.

  6). 6. The organic electroluminescent element according to 5 above, wherein at least one layer of the organic layer is adjacent to a wet method.

  7). 7. The organic electroluminescence device according to 6 above, wherein two layers adjacent to at least one of the organic layers are formed by a wet method.

  8). 8. The organic electroluminescence device according to any one of 1 to 7, wherein the organic electroluminescence device has a light emitting layer as a constituent layer, and the light emitting layer contains a compound represented by the general formula (1).

  9. 9. The organic electroluminescence device according to 8, wherein the light emitting layer contains a phosphorescent metal complex.

  10. 10. The organic electroluminescence device as described in 9 above, wherein the phosphorescent metal complex is a metal complex represented by the following general formula (5).

[In formula, P and Q represent a carbon atom or a nitrogen atom, and A1 represents the atomic group which forms an aromatic-hydrocarbon ring or an aromatic heterocyclic ring with PC. A2 represents an atomic group which forms an aromatic heterocycle with QN. P1-L1-P2 represents a bidentate ligand, and P1 and P2 each independently represent a carbon atom, a nitrogen atom, or an oxygen atom. L1 represents an atomic group that forms a bidentate ligand together with P1 and P2. j1 represents an integer of 1 to 3, j2 represents an integer of 0 to 2, and j1 + j2 is 2 or 3. M ₁ represents a group 8-10 transition metal element in the periodic table. ]
11. 11. The organic electroluminescence device as described in 10 above, wherein A2 represented by the general formula (5) represents an atomic group forming a 5-membered aromatic heterocyclic ring.

  12 12. The organic electroluminescence device as described in 10 or 11 above, wherein the phosphorescent metal complex is a metal complex represented by the following general formula (6).

[Wherein, Z represents a hydrocarbon ring group or a heterocyclic group. P and Q represent a carbon atom or a nitrogen atom, and A1 represents an atomic group that forms an aromatic hydrocarbon ring or an aromatic heterocycle together with PC. A3 represents -C ( _R01 ) = C ( _R02 )-, -N = C ( _R02 )-, -C ( _R01 ) = N- or -N = N-, and _R01 and _R02 represent Represents a hydrogen atom or a substituent. P1-L1-P2 represents a bidentate ligand, and P1 and P2 each independently represent a carbon atom, a nitrogen atom, or an oxygen atom. L1 represents an atomic group that forms a bidentate ligand together with P1 and P2. j1 represents an integer of 1 to 3, j2 represents an integer of 0 to 2, and j1 + j2 is 2 or 3. M ₁ represents a transition metal element of Group 8 to Group 10 in the periodic table. ]
13. 13. The organic electroluminescence device as described in 12 above, wherein Z in the general formula (6) is a group represented by the following general formula (7).

General formula (7)
H _1- (Ar ₁ ) _n −
[In the formula, Ar ₁ represents a group derived from an aromatic hydrocarbon ring or a group derived from an aromatic heterocyclic ring, H ₁ represents a carrier transport unit, and n represents an integer of 0 to 10. ]
14 14. The organic electroluminescence device according to any one of 9 to 13, wherein the phosphorescent metal complex is an Ir complex.

  15. 15. The organic electroluminescence device according to any one of 1 to 14, wherein the organic electroluminescence device emits white light.

  16. An illumination device comprising the organic electroluminescence element according to any one of 1 to 15 above.

  17. 17. A display device comprising the organic electroluminescence element according to any one of 1 to 16 above.

  According to the present invention, an organic EL element exhibiting high luminous efficiency, high durability, and low voltage can be obtained, and a high-luminance display device and lighting apparatus including the organic EL element can be obtained. Also succeeded.

  In the organic EL element of this invention, by having the structure of any one of Claims 1-15, the organic EL element which shows high luminous efficiency, high durability, and low voltage is obtained. In addition, the present inventors have succeeded in obtaining a high-luminance display device and lighting device including the organic EL element.

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

  The organic EL device manufactured (also referred to as production) using the compound represented by the general formula (1) related to the organic EL device of the present invention was able to suppress the occurrence of leakage current and dark spots.

  The reason is that the compound represented by the general formula (1) has a moderate molecular weight and a three-dimensional bulkiness, so that the molecules are less likely to aggregate and the density in the organic layer is uniform and smooth. It is presumed that the flow of electricity is made uniform.

  In addition, when the compound represented by the general formula (1) is mixed with another compound, the density in the organic layer is similarly uniform and a smooth film can be formed.

  Furthermore, in the organic EL device of the present invention, the compound represented by the general formula (1) is used as a host compound (also simply referred to as a host), and the compound represented by the general formula (5) is used as a light emitting dopant. The organic EL element exhibiting particularly high luminous efficiency, high durability and low voltage can be provided.

  The host compound and the light emitting dopant will be described in detail later.

<< Compound Represented by Formula (1) >>
The compound represented by the general formula (1) according to the present invention will be described.

In the general formula (1), R _{11 to} R ₁₈ , R _{21 to} R ₂₈ , R _{31 to} R ₃₆ and R _{41 to} R ₄₈ are each represented by, for example, an alkyl group (for example, a methyl group) , Ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, etc.), cycloalkyl group (for example, cyclopentyl group, cyclohexyl group, etc.) ), Alkenyl groups (for example, vinyl groups, allyl groups, etc.), alkynyl groups (for example, ethynyl groups, propargyl groups, etc.), aromatic hydrocarbon ring groups (aromatic carbocyclic groups, aryl groups, etc.), for example, phenyl Group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, naphthyl group, anthryl group, azulenyl group, aceto group Phenenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group, etc.), aromatic heterocyclic group (for example, pyridyl group, pyrimidinyl group, furyl group, pyrrolyl group, imidazolyl group, benzoimidazolyl group, pyrazolyl group, pyrazinyl group) Group, triazolyl group (for example, 1,2,4-triazol-1-yl group, 1,2,3-triazol-1-yl group, etc.), oxazolyl group, benzoxazolyl group, thiazolyl group, isoxazolyl group, Isothiazolyl group, furazanyl group, thienyl group, quinolyl group, benzofuryl group, dibenzofuryl group, benzothienyl group, dibenzothienyl group, indolyl group, carbazolyl group, carbolinyl group, diazacarbazolyl group (the carboline ring of the carbolinyl group is One of the constituent carbon atoms is nitrogen Quinoxalinyl group, pyridazinyl group, triazinyl group, quinazolinyl group, phthalazinyl group, etc.), heterocyclic group (for example, pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group, etc.), alkoxy group (for example, Methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.), cycloalkoxy group (for example, cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (for example, , Phenoxy group, naphthyloxy group, etc.), alkylthio group (eg, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), cycloalkylthio group (eg, cyclopentyl) O group, cyclohexylthio group, etc.), arylthio group (eg, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxy group) Carbonyl group etc.), aryloxycarbonyl group (eg phenyloxycarbonyl group, naphthyloxycarbonyl group etc.), sulfamoyl group (eg aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylamino) Sulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pi Diylaminosulfonyl group, etc.), acyl groups (for example, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthyl) Carbonyl group, pyridylcarbonyl group, etc.), acyloxy group (eg, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide group (eg, Methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylamino) Carbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), ureido group (For example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido , Phenylureido group, naphthylureido group, 2-pyridylaminoureido group, etc.), sulfinyl group (for example, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group) , Naphthylsulfinyl group, 2-pyridylsulfinyl group, etc.), alkylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), arylsulfonyl group Or a heteroarylsulfonyl group (eg, phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (eg, Group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridylamino group, etc.), halogen atom (for example, fluorine atom) Chlorine atom, bromine atom, etc.), fluorinated hydrocarbon group (for example, fluoromethyl group, trifluoromethyl group, pentafluoroethyl group, pentafluorophenyl group, etc.), cyano group, nitro group, hydroxy group, mercapto group, Examples thereof include a silyl group (for example, trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group, phenyldiethylsilyl group).

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

Among these, R _{11 to} R ₁₈ , R _{21 to} R ₂₈ , R _{31 to} R _36, and R _{41 to} R ₄₈ are preferably a hydrogen atom, an alkyl group, an aromatic hydrocarbon ring group, or an aromatic heterocyclic group. .

In the general formula (1), the linking group represented by X ₁ is an arylene group (for example, o-phenylene group, m-phenylene group, p-phenylene group, naphthalenediyl group, anthracenediyl group, naphthacenediyl group, pyrenediyl group). Group, naphthylnaphthalenediyl group, biphenyldiyl group (for example, [1,1′-biphenyl] -4,4′-diyl group, 3,3′-biphenyldiyl group, 3,6-biphenyldiyl group, etc.), tellurium Phenyldiyl group, quaterphenyldiyl group, kinkphenyldiyl group, sexiphenyldiyl group, septiphenyldiyl group, octylphenyldiyl group, nobiphenyldiyl group, deciphenyldiyl group, etc.), heteroarylene group (for example, Carbazole ring, carboline ring, diazacarbazole ring (also known as monoazacarboline ring) A ring structure in which one of the carbon atoms constituting the carboline ring is replaced by a nitrogen atom), triazole ring, pyrrole ring, pyridine ring, pyrazine ring, quinoxaline ring, thiophene ring, oxadiazole ring, dibenzofuran ring , Dibenzothiophene ring, divalent group derived from the group consisting of indole ring, and the like. These substituents may be further substituted with the above substituents.

In the general formula (1), at least one of the substituted terminals of the linking group represented by X ₁ is a substituent selected from R _{11 to} R ₁₈ , R _{21 to} R ₂₈ , and R _{31 to} R ₃₆ in the general formula (1). Group and a substituent selected from R _{41 to} R ₄₈ are bonded to each other, but a substituent selected from R ₁₃ , R ₁₆ , R ₂₃ , R ₂₆ , R _{31 to} R ₃₆ and R ₄₀ , R ₄₃ , it is preferably bonded with a substituent selected from R _46.

  The compound represented by the general formula (1) preferably has a molecular weight in the range of 700 to 5000, and more preferably in the range of 800 to 3000.

In the general formula (1), any two of R _{31 to} R ₃₆ are preferably bonded to R ₁₆ and R _23, and R ₃₁ and R ₁₆ are further bonded, and R ₃₃ and R ₂₃ are bonded. Is more preferably bonded.

  When n is 2 or more, the bonding position of the dibenzothiophene unit and the phenylene unit in () n may be different.

<< Compound Represented by General Formula (2), (3) or (4) >>
Among the compounds represented by the general formula (1), the compounds represented by the general formula (2), (3) or (4) are preferably used.

Formula (2), (3) or in the compounds represented by _(4), R 11 _{to R 18} and _R 21 _{to R 28} is, _R 11 _{to R 18} and _R 21 in the general formula (1) to R ₂₈ is synonymous with each other.

  The compound represented by the general formula (1) according to the present invention, the compound represented by the general formula (2), (3) or (4), which is a preferred embodiment of the compound represented by the general formula (1). Can be used in any of the constituent layers (organic layers) of the organic EL device of the present invention, but is preferably contained as a host compound in the light emitting layer.

  The constituent layers of the organic EL device of the present invention and the compounds contained in the constituent layers will be described in detail later.

  Specific examples of the compound represented by the general formula (1) and the compound represented by the general formula (2), (3) or (4) are shown below, but the present invention is not limited thereto.

<< Synthesis of Exemplified Compound H-4 >>
Hereinafter, although an example (example compound H-1) of a synthesis | combination of the compound represented by General formula (1) based on this invention is shown, this invention is not limited to these.

  Process (1)

  Hereinafter, although an example (example compound H-1) of a synthesis | combination of the compound represented by General formula (1) based on this invention is shown, this invention is not limited to these.

  After adding 1122 ml of acetic acid, 198 ml of acetic anhydride, and 95.6 g of iodobenzene diacetate to 109 g of the raw material 1, 78.5 g of iodine and 1.65 ml of sulfuric acid were added alternately in several portions, The mixture was heated and stirred at room temperature for 3 hours.

  Insoluble matter in the reaction solution was filtered, washed with methanol, and dried to obtain 57.1 g of Intermediate 2. The yield was 31%.

  The structure of the obtained intermediate 2 was confirmed by nuclear magnetic resonance spectrum and mass spectrum.

  Step (2)

  Bromine was added dropwise to 30 g of Intermediate 2 where 500 ml of acetic acid was completely dissolved, and the mixture was heated and stirred at 60 ° C. for 16 hours.

  After the reaction solution was cooled to room temperature, insoluble matters were filtered, washed with a mixed solution of methanol and tetrahydrofuran, and dried to obtain 20.8 g of Intermediate 3. The yield was 55%.

  The structure of the obtained intermediate 3 was confirmed by a nuclear magnetic resonance spectrum and a mass spectrum.

  Process (3)

  To 3 g of Intermediate 3, 4.9 g of carbazole, 5.1 g of copper powder, 5.6 g of potassium carbonate, and 300 ml of dimethylacetamide (dehydrated) were added and stirred at 150 ° C. for 10 hours under a nitrogen stream.

  The reaction mixture was cooled to room temperature, insolubles were filtered, brine was added, and the mixture was extracted with tetrahydrofuran. The organic layer was repeatedly washed with water and concentrated under reduced pressure.

  The resulting mixture was purified by silica gel column chromatography to obtain 36.8 g of Intermediate 4. The yield was 32%.

  The structure of the obtained intermediate 4 was confirmed by nuclear magnetic resonance spectrum and mass spectrum.

  Process (4)

Intermediate 35 (35 g), bis (pinacolato) diboron (23.1 g), potassium acetate (12.2 g), PdCl ₂ (dppf) CH ₂ Cl _{2 (} 1.0 ml) was added with dimethyl sulfoxide (300 ml), and the mixture was heated and stirred at 100 ° C. for 16 hours in a nitrogen stream. .

  The reaction mixture was cooled to room temperature, insolubles were filtered, water was added, and the mixture was extracted with ethyl acetate. The organic layer was repeatedly washed with water and concentrated under reduced pressure.

  The resulting mixture was purified by silica gel column chromatography to obtain 31 g of Intermediate 5. The yield was 80%.

  The structure of the obtained intermediate 5 was confirmed by a nuclear magnetic resonance spectrum and a mass spectrum.

  Step (5)

  To 0.29 g of palladium acetate, 2.1 g of a 50 mass% toluene solution of tert-butylphosphine and 10 ml of xylene (dehydrated) were added, and the mixture was stirred at room temperature for 1 hour in a nitrogen stream. Subsequently, 10.5 g of Intermediate 5, 3.0 g of 1,3-diiodobenzene, 2.1 g of sodium t-butoxide and 120 ml of xylene (dehydrated) were added, and the mixture was heated to reflux for 5 hours under a nitrogen stream.

  After cooling the reaction solution to room temperature, insolubles were filtered, water was added, and the mixture was extracted with toluene. The organic layer was repeatedly washed with water and concentrated under reduced pressure.

  The resulting mixture was purified by silica gel column chromatography and further recrystallized from toluene to obtain 5.7 g of exemplary compound H-1. The yield was 80%.

  The obtained exemplary compound H-1 was confirmed in structure by nuclear magnetic resonance spectrum and mass spectrum.

<< Metal Complex Represented by Formula (5) >>
The metal complex represented by the general formula (5) according to the present invention will be described.

  In the organic EL device of the present invention, the light emitting layer preferably contains a phosphorescent metal complex, and more preferably, the phosphorescent metal complex is represented by the general formula (5). That is. The light emitting layer will be described in detail in the constituent layers of the organic EL element described later.

In General formula (5), P and Q represent a carbon atom or a nitrogen atom, A1 represents the atomic group which forms an aromatic-hydrocarbon ring or an aromatic heterocyclic ring with PC. A2 represents an atomic group that forms an aromatic hydrocarbon ring or an aromatic heterocyclic ring together with QN. P1-L1-P2 represents a bidentate ligand, and P1 and P2 each independently represent a carbon atom, a nitrogen atom, or an oxygen atom. L1 represents an atomic group that forms a bidentate ligand together with P1 and P2. j1 represents an integer of 1 to 3, j2 represents an integer of 0 to 2, and j1 + j2 is 2 or 3. M ₁ that is a central metal represents a group 8-10 transition metal element in the periodic table.

In the general formula (5), the aromatic hydrocarbon ring represented by A1 is specifically a benzene ring, chlorobenzene ring, mesitylene ring, toluene ring, xylene ring, naphthalene ring, anthracene ring, azulene ring, acenaphthene ring. Fluorene ring, phenanthrene ring, indene ring, pyrene ring, biphenyl ring, terphenyl ring, perylene ring and the like. Further, the hydrocarbon ring group may be substituted with the substituents described in the examples of the substituents of R _{11 to} R ₁₈ , R _{21 to} R ₂₈ , R _{31 to} R ₃₆ and R _{41 to} R ₄₈ described above. A condensed ring (for example, a quinoline ring obtained by condensing a heterocyclic ring with a benzene ring) may be formed.

In the general formula (5), the aromatic heterocycle represented by A1 or A2 specifically includes an oxazole ring, oxadiazole ring, oxatriazole ring, isoxazole ring, tetrazole ring, thiadiazole ring, thiatriazole A ring, an isothiazole ring, a thiophene ring, a furan ring, a pyrrole ring, an imidazole ring, a pyrazole ring, a triazole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a diazine ring, and a triazine ring. Further, the heterocyclic ring may be substituted with the substituents described in the examples of the substituents R _{11 to} R ₁₈ , R _{21 to} R ₂₈ , R _{31 to} R ₃₆ and R _{41 to} R ₄₈ described above, and further condensed. A ring may be formed.

  A1 is preferably a benzene ring, a naphthalene ring, a pyridine ring, a pyrimidine ring, a pyrrole ring, a thiophene ring, a pyrazole ring, an imidazole ring, an oxazole ring, and a thiazole ring, more preferably a benzene ring, a naphthalene ring, a thiophene ring, and A pyridine ring, most preferably a benzene ring.

  A2 is preferably a pyridine ring, pyrimidine ring, triazine ring, pyrrole ring, pyrazole ring, imidazole ring, triazole ring, oxazole ring and thiazole ring, more preferably a pyridine ring, triazine ring, imidazole ring, triazole ring, oxazole ring. And a 5-membered aromatic heterocyclic ring (for example, oxazole ring, oxadiazole ring, oxatriazole ring, isoxazole ring, tetrazole ring, thiadiazole ring, thiatriazole ring, isothiazole ring, thiophene ring) A furan ring, a pyrrole ring, an imidazole ring, a pyrazole ring, a triazole ring, etc.), most preferably an imidazole ring and a triazole ring.

  In the general formula (5), specific examples of the bidentate ligand represented by P1-L1-P2 include substituted or unsubstituted phenylpyridine, phenylpyrazole, phenylimidazole, phenyltriazole, phenyltetrazole, pyrazabol, Examples include acetylacetone and picolinic acid.

  j1 represents an integer of 1, 2 or 3, j2 represents an integer of 0, 1 or 2, and j1 + j2 is 2 or 3. Among these, j2 is preferably 0.

In General Formula (5), M ₁ is a transition metal element belonging to Group 8 to 10 in the periodic table (also simply referred to as a transition metal). Among them, iridium and platinum are preferable, and iridium is particularly preferable.

  In the present invention, among the metal complexes represented by the general formula (5), the metal complex represented by the general formula (6) is preferably used.

<< Metal Complex Represented by General Formula (6) >>
The metal complex represented by the general formula (6) according to the present invention will be described.

In General formula (6), Z represents a hydrocarbon ring group or a heterocyclic group. P and Q represent a carbon atom or a nitrogen atom, and A1 represents an atomic group that forms an aromatic hydrocarbon ring or an aromatic heterocycle together with PC. A3 is an atomic group that forms an aromatic heterocycle with NQN, and is —C (R ₀₁ ) ═C (R ₀₂ ) —, _—N═C (R ₀₂ ) —, —C (R ₀₁ ) = N— or —N═N—, and R ₀₁ and R ₀₂ represent a hydrogen atom or a substituent. P1-L1-P2 represents a bidentate ligand, and P1 and P2 each independently represent a carbon atom, a nitrogen atom, or an oxygen atom. L1 represents an atomic group that forms a bidentate ligand together with P1 and P2. j1 represents an integer of 1 to 3, j2 represents an integer of 0 to 2, and j1 + j2 is 2 or 3. M ₁ which is the central metal represents a group 8 to 10 metal in the periodic table.

  In the general formula (6), the aromatic hydrocarbon ring and aromatic heterocycle represented by A1 have the same meaning as the aromatic hydrocarbon ring or aromatic heterocycle represented by A1 in the general formula (5). , Preferably a benzene ring, naphthalene ring, pyridine ring, pyrimidine ring, pyrrole ring, thiophene ring, pyrazole ring, imidazole ring, oxazole ring and thiazole ring, more preferably a benzene ring, naphthalene ring, thiophene ring and pyridine ring. And most preferably a benzene ring.

  In the general formula (6), the nitrogen-containing aromatic heterocycle formed together with A3 and NQN is synonymous with the aromatic heterocycle represented by A2 in the general formula (5), and preferably Examples include an imidazole ring, a triazole ring, and a tetrazole ring. Particularly preferred is an imidazole ring.

R ₀₁ and R ₀₂ represent a hydrogen atom or a substituent. Examples of the substituent are the same as the above-described substituent examples of R _{11 to} R ₁₈ , R _{21 to} R ₂₈ , R _{31 to} R _36, and R _{41 to} R ₄₈ . Also in R ₀₁ and R ₀₂ , the substituent is further substituted with a substituent selected from the examples of the substituents of R _{11 to} R ₁₈ , R _{21 to} R ₂₈ , R _{31 to} R ₃₆ and R _{41 to} R _48. In addition, a plurality of substituents may be bonded to each other to form a ring.

The type of substituent in R ₀₁ and R ₀₂ is preferably a hydrogen atom, an alkyl group, an aromatic hydrocarbon ring group or an aromatic heterocyclic group.

  In the general formula (6), specific examples of the bidentate ligand represented by P1-L1-P2 include a bidentate ligand represented by P1-L1-P2 in the general formula (5) and It is synonymous.

  j1 represents an integer of 1, 2 or 3, j2 represents an integer of 0, 1 or 2, and j1 + j2 is 2 or 3. Among these, j2 is preferably 0.

In the general formula (6), M ₁ is a transition metal element belonging to Group 8 to 10 in the periodic table of elements (also simply referred to as a transition metal), among which iridium and platinum are preferable, and iridium is particularly preferable.

  In the general formula (6), examples of the hydrocarbon ring group represented by Z include a non-aromatic hydrocarbon ring group and an aromatic hydrocarbon ring group, and examples of the non-aromatic hydrocarbon ring group include a cyclopropyl group. , Cyclopentyl group, cyclohexyl group and the like. These groups may be unsubstituted or have a substituent described later.

Examples of the aromatic hydrocarbon ring group (also referred to as aromatic hydrocarbon group, aryl group, etc.) include, for example, phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, naphthyl group, anthryl group, azulenyl. Group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group and the like. These groups may be unsubstituted or may have a substituent represented by R _{11 to} R ₁₈ in the general formula (1).

  In the general formula (6), examples of the heterocyclic group represented by Z include a non-aromatic heterocyclic group and an aromatic heterocyclic group. Examples of the non-aromatic heterocyclic group include an epoxy ring and an aziridine group. Ring, thiirane ring, oxetane ring, azetidine ring, thietane ring, tetrahydrofuran ring, dioxolane ring, pyrrolidine ring, pyrazolidine ring, imidazolidine ring, oxazolidine ring, tetrahydrothiophene ring, sulfolane ring, thiazolidine ring, ε-caprolactone ring, ε- Caprolactam ring, piperidine ring, hexahydropyridazine ring, hexahydropyrimidine ring, piperazine ring, morpholine ring, tetrahydropyran ring, 1,3-dioxane ring, 1,4-dioxane ring, trioxane ring, tetrahydrothiopyran ring, thiomorpholine Ring, thiomorpholine-1,1-dioxide And groups derived from a ring, a pyranose ring, a diazabicyclo [2,2,2] -octane ring, and the like. These groups may be unsubstituted or have a substituent.

  The hydrocarbon ring group or heterocyclic group represented by Z is preferably a group represented by the following general formula (7).

General formula (7)
H _1- (Ar ₁ ) _n −
Ar ₁ represented by the general formula (7) represents a group derived from an aromatic carbon aromatic hydrocarbon ring or a group derived from an aromatic heterocyclic ring, H ₁ represents a carrier transport unit, and n represents The integer of 0-10 is represented.

The aromatic heterocyclic ring used for forming the group derived from the aromatic hydrocarbon ring or aromatic heterocyclic ring used for forming the group derived from the aromatic hydrocarbon ring represented by Ar ₁ has the general formula It is synonymous with the aromatic hydrocarbon ring or aromatic heterocycle represented by A1 in (5).

The carrier transport unit represented by H ₁ is a compound that has an aromatic hydrocarbon ring or aromatic heterocycle as a partial structure and transports carriers.

  The carrier transport unit according to the present invention refers to a general organic EL electron transport material, hole transport material, and host material, and is preferably a carbazole derivative.

Examples of the aromatic hydrocarbon ring used for forming the group derived from the aromatic hydrocarbon ring represented by Ar ₁ include a benzene ring, a p-chlorobenzene ring, a mesitylene ring, a toluene ring, a xylene ring, a phthalene ring, and an anthracene. And a ring, an azulene ring, an acenaphthene ring, a fluorene ring, a phenanthrene ring, an indene ring, a pyrene ring, a biphenyl ring, a terphenyl ring, and a perylene ring.

The aromatic heterocycle used for forming the group derived from the aromatic heterocycle represented by Ar ₁ includes an oxazole ring, an oxadiazole ring, an oxatriazole ring, an isoxazole ring, a tetrazole ring, a thiadiazole ring, Examples include triazole ring, isothiazole ring, thiophene ring, furan ring, pyrrole ring, imidazole ring, pyrazole ring, triazole ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, diazine ring, and triazine ring.

The aromatic heterocyclic ring used for forming the group derived from the aromatic hydrocarbon ring or aromatic heterocyclic ring used for forming the group derived from the aromatic hydrocarbon ring represented by Ar ₁ has a substituent. The substituent may be an alkyl group (for example, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, Pentadecyl group, etc.) and alkoxy groups (for example, methoxy group, ethoxy group, propyloxy group, isopropyloxy group, tert-butyloxy group, pentyloxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.) are preferable. An alkyl group (eg, isopropyl group, tert-butyl group, etc.) or branched alkoxy group (eg, Sopropyloxy group, tert-butyloxy group, etc.) are more preferable.

  Hereinafter, preferred examples of Z will be given, but Z is not limited to these examples, and may further have a substituent other than the following examples. Note that * represents a bonding position.

  The molecular weight of each of the metal complex represented by the general formula (5) and the metal complex represented by the general formula (6) is not particularly specified, but is preferably in the range of 900 to 3000, more preferably 900 to 2000. It is a range.

  Although the specific example of the compound used as a phosphorescent dopant below is shown, this invention is not limited to these. These compounds are described, for example, in Inorg. Chem. 40, 1704-1711, and the like.

  Although the synthesis example of the metal complex based on this invention is shown below, this invention is not limited to these.

  << Synthesis of Exemplified Compound D-39 >>

Step 1: Synthesis of Complex A Iridium chloride was added to a solution of 18 g (0.06861 mol) of 2-phenyl- (2,4,6-trimethylphenyl) -1H-imidazole in 350 ml of 2-ethoxyethanol under a nitrogen atmosphere. Trihydrate, 8.1 g (0.02297 mol) and 100 ml of water were added and refluxed for 5 hours under a nitrogen atmosphere. The reaction solution was cooled, 500 ml of methanol was added, and the precipitated crystals were collected by filtration. The obtained crystals were further washed with methanol and dried to obtain 15.2 g (yield 88.4%) of Complex A.

Step 2: Synthesis of Exemplified Compound D-39 6.0 g (0.003998 mol) of Complex A and 1.85 g (0.008396 mol) of silver trifluoroacetate obtained in Step 1 were added in 500 ml of methylene chloride. The mixture was refluxed for 1 hour with nitrogen bubbling.

  After cooling the reaction solution, the salt was filtered off, the filtrate was concentrated, 500 ml of tetrahydrofuran was added, 3.2 g (0.007996 mol) of carbene precursor and 1.35 g of tert-butoxy potassium were added, and the mixture was refluxed for 5 hours. . After cooling the reaction solution, the insoluble material was filtered off and the filtrate was concentrated. The obtained residue was separated and produced by silica gel column chromatography (hexane / tetrahydrofuran) to obtain 5.33 g (65.0%) of Exemplary Compound D-39.

  The above synthesis method is an example, and the present invention is not limited thereto. For example, various compounds can be synthesized by changing the solvent to be used to a polar solvent having a high boiling point such as phenyl acetate, or changing the amount of the reaction substrate to change the reaction temperature.

  Further, the dopant used in the present invention is not limited to the one according to the present invention, and by combining with other dopants, the emission intensity can be increased and the emission peak can be shifted. In particular, an organic EL element that emits white light can be achieved by mixing a plurality of dopants.

  Although an example of the light emission dopant used for this invention below is shown, this invention is not limited to these.

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

(I) Anode / light emitting layer / electron transport layer / cathode (ii) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (iii) Anode / hole transport layer / light emitting layer / hole blocking layer / electron Transport layer / cathode (iv) Anode / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode (v) Anode / anode buffer layer / hole transport layer / light emitting layer / hole Blocking layer / electron transport layer / cathode buffer layer / cathode << organic compound layer (also referred to as organic layer) >>
The organic compound layer 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. Examples of the organic compound layer include a hole transport layer, a light emitting layer, and a hole blocking layer in the above layer constitution. In addition, an organic compound layer according to the present invention is defined as long as it contains an organic compound contained in a constituent layer of an organic EL element, such as a hole injection layer or an electron injection layer. Is done.

  Further, when an organic compound is used for the anode buffer layer, the cathode buffer layer, etc., the anode buffer layer, the cathode buffer layer, etc. 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.

<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 film thickness of the light emitting layer is not particularly limited, but it is 2 nm to from the viewpoint of preventing the application of a high voltage unnecessary for the film homogeneity and light emission and improving the stability of the emission color with respect to the drive current. It is preferable to adjust to the range of 5 micrometers, More preferably, it adjusts to the range of 2 nm-200 nm, Most preferably, it is the range of 10 nm-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 host compound and at least one kind of light emitting dopant (phosphorescent dopant, fluorescent dopant, etc.).

《Host compound》
The host compound used in the present invention will be described.

  Here, in the present invention, the host compound is defined as a compound having a phosphorescence quantum yield of phosphorescence emission of less than 0.1 at room temperature (25 ° C.) among compounds contained in the light emitting layer. 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 represented by the general formula (1) is preferably used as the host compound, and more preferably the compound represented by the general formula (2), (3) or (4) is used as the host compound. Particularly preferably used.

  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 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.

《Light emitting dopant》
The light emitting dopant according to the present invention will be described.

  As the light emitting dopant according to the present invention, a fluorescent dopant or a phosphorescent light emitting dopant can be used. From the viewpoint of obtaining an organic EL element with higher luminous efficiency, the light emitting layer or light emitting unit of the organic EL element of the present invention. As the luminescent dopant used in the above, it is preferable to contain the above-mentioned host compound and at the same time a phosphorescent dopant.

《Phosphorescent dopant》
The phosphorescent dopant according to the present invention will be described.

  The phosphorescent dopant according to the present invention 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 has a phosphorescence quantum yield. The phosphorescence quantum yield is preferably 0.1 or more, although it is defined as a compound of 0.01 or more at 25 ° C.

  The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence emitting dopant 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 light emission of phosphorescent dopants 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. The energy transfer type is to obtain light emission from the phosphorescent dopant by transferring to the phosphorescent dopant, and the other is that the phosphorescent dopant becomes a carrier trap, and carrier recombination occurs on the phosphorescent dopant to cause phosphorescence. There is a carrier trap type in which light emission from a photoluminescent dopant can be obtained.

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

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

  The phosphorescent dopant according to the present invention is preferably a complex compound containing a transition metal element of group 8 to 10 in the periodic table, more preferably an iridium compound (Ir complex), an osmium compound, or platinum. Compounds (platinum complex compounds) and rare earth complexes, and most preferred are iridium compounds (Ir complexes).

  Further, as a preferred phosphorescent dopant in the present invention, a compound represented by the above general formula (5) or general formula (6) (also referred to as a metal complex or a metal complex compound) is preferable.

<Fluorescent dopant>
As fluorescent dopants, coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, perylene dyes, stilbene dyes , Polythiophene dyes, or 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.

  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 transporting layer according to the present invention is preferably 3 to 100 nm, and more preferably 5 to 30 nm.

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

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

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

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

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

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

  The hole transport layer can be formed by thinning the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. it can. Although there is no restriction | limiting in particular about the film thickness of a positive hole transport layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5-200 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, and JP-A-2001-102175; 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.

  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 5-200 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 to 1000 nm, preferably 10 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₎ mixture, indium, a lithium / aluminum mixture, and rare earth metals.

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

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

  Moreover, after producing the said metal with a film thickness of 1-20 nm on a cathode, a 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 Polyetherimide, polyether ketone imide, polyamide, fluorine resin, nylon, polymethyl methacrylate, acrylic or polyarylates, and cycloolefin resins such as ARTON (JSR Corp.) or APEL (manufactured by Mitsui Chemicals, Inc.).

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. , it is preferable that the relative humidity of (90 ± 2)% RH) is a barrier film of 0.01g ^/ (m 2 · 24h) or less, more oxygen permeability measured by the method based on JIS K 7126-1987 A high barrier film having a degree 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, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster ion beam, ion plating, plasma polymerization, atmospheric pressure plasma polymerization A plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used, but an atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferable.

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

  The external extraction quantum 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. 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 an 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. The water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) measured in (1) is preferably 1 × 10 ⁻³ g / (m ² · 24 h) or less.

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

  Specific examples of the adhesive include photocuring and thermosetting adhesives having reactive vinyl groups such as acrylic acid oligomers and methacrylic acid oligomers, and moisture curing adhesives such as 2-cyanoacrylates. be able to.

  Moreover, heat | fever and chemical curing types (two-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 adhesively cured from room temperature to 80 is preferable. A desiccant may be dispersed in the adhesive. Application | coating of the adhesive agent to a sealing part may use commercially available dispenser, and may print like screen printing.

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

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

  In the gap between the sealing member and the display area of the organic EL element, it is preferable to inject an inert gas such as nitrogen or argon, or an inert liquid such as fluorinated hydrocarbon or silicon oil in the gas phase and the liquid phase. . A vacuum can also be used. 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, etc. used for the sealing can be used. It is preferable to use a film.

《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 only 15% to 20% of light generated in the light emitting layer can be extracted. It is generally said that there is no.

  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 extracted outside the device, or between the transparent electrode or light emitting layer and the transparent substrate. This is because the light undergoes total reflection between the light and the light, and the light is guided through the transparent electrode or the light emitting layer.

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

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

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

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

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

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

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

  This method uses the property that the diffraction grating can change the direction of light to a specific direction different from refraction by so-called Bragg diffraction such as first-order diffraction and second-order diffraction. Of these, light that cannot be emitted due to total reflection between layers, etc. is diffracted by introducing a diffraction grating into any layer or medium (inside a transparent substrate or transparent electrode), and the light is emitted outside. 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 to provide, for example, a microlens array-like structure on the light extraction side of the substrate, or in combination with a so-called condensing sheet, so that the organic EL device is in front of a specific direction, for example, the device light emitting surface. By condensing in the direction, the luminance in a specific direction can be increased.

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

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

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

<< Method for producing organic EL element >>
As an example of the method for producing the organic EL device of the present invention, a method for producing an organic EL device comprising an anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer / cathode Will be explained.

  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 is formed thereon.

  As a method for forming each of these layers, there are a vapor deposition method and a coating method (spin coating method, casting method, ink jet method, printing method) as described above, but it is easy to obtain a homogeneous film and it is difficult to generate pinholes. In view of the above, 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.

  At least one layer of the organic layer (also referred to as an organic compound layer) according to the present invention contains the compound represented by the general formula (1), but at least one layer of the organic layer is formed by a wet method. It is preferable that one layer adjacent to at least one of the organic layers is formed by a wet method, and it is particularly preferable that two layers adjacent to at least one of the organic layers are wet. Is to be formed by law.

  In particular, the organic layer containing the compound represented by the general formula (1) 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 the constituent layers of the organic EL device of the present invention are formed 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 cyclohexanone, and fatty acid esters such as ethyl acetate. , Halogenated hydrocarbons such as dichlorobenzene, aromatic hydrocarbons such as toluene, xylene, mesitylene and cyclohexylbenzene, aliphatic hydrocarbons such as cyclohexane, decalin and dodecane, and organic solvents such as DMF and DMSO be able to.

  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 a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably in the range of 50 nm to 200 nm, and a cathode is provided. Thus, 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 anode as + and the cathode as-polarity. 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, It can use effectively for the use as a backlight of a liquid crystal display device, and an illumination light source especially.

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

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

When the organic EL element of the present invention is a white element, white means that the chromaticity in the CIE 1931 color system at 1000 cd / m ² is X = It is in the region of 0.33 ± 0.07, Y = 0.33 ± 0.1.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these. In addition, although the display of "%" is used in an Example, unless otherwise indicated, "mass%" is represented.

Example 1
<< Preparation of model thin film 1 of light emitting layer of organic EL element >>
A quartz substrate of 30 mm × 30 mm × 1.1 mm was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes, then attached to a commercially available spin coater, H-1 (50 mg) and Ir A solution of -15 (5 mg) dissolved in 10 ml of toluene was formed by spin coating at 1500 rpm for 30 seconds, and further vacuum dried at 25 ° C. for 1 hour to obtain a model thin film 1 having a thickness of 25 nm. Produced.

<< Production of Model Thin Films 2 to 12 of Light-Emitting Layer of Organic EL Element >>
In the production of the model thin film 1, model thin films 2 to 12 were produced in the same manner except that the host compound H-1 was changed as shown in Table 1.

<< Ra measurement, P-to-V measurement >>
About the obtained model thin films 1-12, the apparatus name: SPI3800N DFM made from SII, cantilever: SI-DF20 was used, and the surface roughness was measured by measurement area: 50 micrometers x 50 micrometers, 10 micrometers x 10 micrometers.

  Here, Ra is a kind of JIS roughness shape parameter (JIS B0601-1994) and represents the centerline average roughness. The roughness curve is folded back from the center line, and the value obtained by dividing the area obtained by the roughness curve and the center line by the length L is expressed as a Ra value in micrometers (μm) (see FIG. 1).

  P-to-V is the same as Ry, which is a kind of JIS roughness shape parameter (JIS B0601-1994), and represents the height from the lowest valley bottom to the highest mountain peak for each reference length. The maximum height of the section from which the reference length L is extracted from the cross-sectional curve is obtained and expressed in micrometers (μm), which is defined as a P-to-V value or a Ry value.

  Here, the cross-sectional curve represents a contour that appears at the cut end when the surface to be measured is cut along a plane perpendicular to the surface to be measured.

  Ra and P-to-V were obtained based on the obtained surface roughness data.

  The obtained Ra measurement values and P-to-V measurement values are shown in Table 1.

  From Table 1, the model thin films 1 to 9 containing the compound represented by the general formula (1) can form a thin film having a low smoothness with a low P-to-V value as compared with the comparative thin films 10 to 12. I understood.

Example 2
<< Production of Organic EL Element 1-1 >>
After patterning on a substrate (NA-45 manufactured by NH Techno Glass Co., Ltd.) 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 at 3000 rpm for 30 seconds. After forming the film by spin coating, the film was dried at 200 ° C. for 1 hour to provide a 20 nm-thick hole transport layer.

  This substrate was transferred to a nitrogen atmosphere, and a solution of 50 mg of the hole transport material 1 dissolved in 10 ml of toluene was formed on the hole transport layer by spin coating at 1500 rpm for 30 seconds. In a nitrogen atmosphere, ultraviolet light was irradiated for 180 seconds to carry out photopolymerization and crosslinking to form a second hole transport layer having a thickness of about 20 nm.

  On this second hole transport layer, a solution prepared by dissolving 100 mg of Comparative Compound 1 and 10 mg of D-3 in 10 ml of toluene was formed by spin coating at 1000 rpm for 30 seconds. It vacuum-dried at 120 degreeC for 1 hour, and was set as the light emitting layer with a film thickness of about 50 nm.

  Next, a solution obtained by dissolving 50 mg of the electron transport material 1 in 10 ml of 1-butanol was formed on this light emitting layer by spin coating under a condition of 5000 rpm for 30 seconds. It vacuum-dried at 60 degreeC for 1 hour, and was set as the electron carrying layer with a film thickness of about 15 nm.

Subsequently, this substrate is fixed to a substrate holder of a vacuum deposition apparatus, the vacuum chamber is decompressed to 4 × 10 ⁻⁴ Pa, lithium fluoride 1.0 nm is deposited as a cathode buffer layer, and aluminum 110 nm is deposited as a cathode to form a cathode. Then, an organic EL element 1-1 was produced.

<< Production of Organic EL Elements 1-2 to 1-11 >>
Organic EL elements 1-2 to 1-11 were respectively prepared in the same manner as the organic EL element 1-1 except that the comparative compound 1 was changed to the compounds shown in Table 2 in the preparation of the organic EL element 1-1.

<< Evaluation of Organic EL Elements 1-1 to 1-11 >>
When evaluating the obtained organic EL elements 1-1 to 1-11, the non-light-emitting surface of each organic EL element after production was covered with a glass case, and a glass substrate having a thickness of 300 μm was used as a sealing substrate. An epoxy-based photo-curing adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is applied as a sealing material in the periphery, and this is placed on the cathode to be in close contact with the transparent support substrate and irradiated with UV light from the glass substrate side Then, it was cured and sealed, and an illumination device as shown in FIGS. 2 and 3 was formed and evaluated.

  FIG. 2 is a schematic diagram of the lighting device, and the organic EL element 201 is covered with a glass cover 202. Note that the sealing operation with the glass cover was performed in a glove box in a nitrogen atmosphere without bringing the organic EL element 201 into contact with the atmosphere (in a high purity nitrogen gas atmosphere with a purity of 99.999% or more).

  FIG. 3 is a cross-sectional view illustrating one embodiment of the lighting device of the present invention. In FIG. 3, 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.

  Subsequently, the light emission lifetime was measured as follows.

(External extraction quantum efficiency)
About the produced organic EL element, external extraction quantum efficiency (%) when ^2.5 mA / cm ² constant current was applied in a dry nitrogen gas atmosphere at 23 ° C. was measured.

  For the measurement, a spectral radiance meter CS-1000 (manufactured by Konica Minolta) was used in the same manner.

  The measurement results of the external extraction quantum efficiency in Table 1 are expressed as relative values when the measured value of the organic EL element 1-1 is 100.

(lifespan)
When driven at a constant current of ^2.5 mA / cm ² , the time required for the luminance to drop to half of the luminance immediately after the start of light emission (initial luminance) was measured, and this was calculated as the half-life time (τ 0.5). As an index of life.

  For the measurement, a spectral radiance meter CS-1000 (manufactured by Konica Minolta) was used.

  The lifetime measurement results in Table 1 are expressed as relative values when the organic EL element 1-1 is taken as 100.

  The obtained results are shown in Table 2.

  From Table 2, it is clear that the organic EL device of the present invention exhibits high external extraction quantum efficiency, a low driving voltage, and a long emission lifetime as compared with the comparison.

  In addition, it was found that the generation of dark spots was clearly less in the elements 1-4 to 1-11 than in the comparative elements 1-1 to 1-3.

  Further, in addition to the dopant Ir-11 used in the present example, the dopant compounds usable in the invention, Ir-21, Ir-27, and the dopant exemplified compounds 116, D-2, D-3 are also element 1 respectively. When the host compounds corresponding to -1 to 1-11 were evaluated, the same effect was obtained.

Example 3
<< Production of organic EL full-color display device >>
FIG. 4 shows a schematic configuration diagram of an organic EL full-color display device. After patterning at a pitch of 100 μm on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) formed by forming a 100 nm ITO transparent electrode (102) on a glass substrate 101 as an anode, non-between the ITO transparent electrodes on this glass substrate. A photosensitive polyimide partition 103 (width 20 μm, thickness 2.0 μm) was formed by photolithography.

  A hole injection layer composition having the following composition is ejected and injected between polyimide partition walls on the ITO electrode using an inkjet head (manufactured by Epson; MJ800C), irradiated with ultraviolet light for 2 minutes, and dried at 60 ° C. for 10 minutes. A hole injection layer 104 having a thickness of 40 nm was produced by the treatment.

  On the hole injection layer, the following blue light-emitting layer composition, green light-emitting layer composition, and red light-emitting layer composition were similarly discharged and injected using an inkjet head, and dried at 60 ° C. for 10 minutes. Each light emitting layer (105B, 105G, 105R) was formed. Finally, Al (106) was vacuum-deposited as a cathode so as to cover the light emitting layer 105, and an organic EL element was produced.

  It was found that the produced organic EL element showed blue, green, and red light emission by applying a voltage to each electrode, and could be used as a full-color display device.

(Hole injection layer composition)
Hole transport material 1 20 parts by mass Cyclohexylbenzene 50 parts by mass Isopropyl biphenyl 50 parts by mass (Blue light emitting layer composition)
H-3 0.7 parts by mass Ir-11 0.04 parts by mass Cyclohexylbenzene 50 parts by mass Isopropyl biphenyl 50 parts by mass (green light emitting layer composition)
H-3 0.7 parts by mass Ir-1 0.04 parts by mass Cyclohexylbenzene 50 parts by mass Isopropylbiphenyl 50 parts by mass (red light emitting layer composition)
H-3 0.7 parts by weight Ir-6 0.04 parts by weight Cyclohexylbenzene 50 parts by weight Isopropylbiphenyl 50 parts by weight (electron transport layer composition)
Electron transport material 1 20 parts by mass 1-butanol 50 parts by mass Isopropyl biphenyl 50 parts by mass Organic EL elements prepared using compounds H-1, 12, and 26 instead of H-3 can also be used as full-color display devices. I understood.

Example 4
<< Production of White Organic EL Element 3-1 >>
A hole transport layer / second hole transport layer was formed by spin coating on the transparent electrode substrate of Example 2 in the same manner as in Example 2, and 100 mg of Compound H-8, 10 mg of the light emitting layer was further formed. A solution of Exemplified Compound D-3 and 0.1 mg of D-38 dissolved in 10 ml of toluene was formed into a film by spin coating under conditions of 1000 rpm and 30 seconds. It vacuum-dried at 120 degreeC for 1 hour, and was set as the light emitting layer of film thickness of about 50 nm.

  Next, in the same manner as in Example 2, an electron transport layer, a lithium fluoride layer, and an aluminum cathode were formed to produce a white light-emitting organic EL element 3-1. The obtained organic EL element 3-1 was sealed in the same manner as in Example 2.

  When this organic EL element 3-1 was energized, in the CIE 1931 chromaticity diagram, substantially white light of (X, Y) = (0.38, 0.45) was obtained, and it was found that it could be used as a lighting device. .

  It has been found that even when the host compound is replaced with another compound according to the present invention, white light emission can be obtained.

It is a conceptual diagram which shows the relationship between a roughness curve and centerline average roughness Ra. It is the schematic of an illuminating device. It is sectional drawing of an illuminating device. The schematic block diagram of an organic electroluminescent full color display apparatus is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Glass substrate 102 ITO transparent electrode 103 Partition 104 Hole injection layer 105B, 105G, 105R Light emitting layer 201 Organic EL element 207 Glass substrate with a transparent electrode 206 Organic EL layer 205 Cathode 202 Glass cover 208 Nitrogen gas 209 Water capturing agent

Claims (17)

In an organic electroluminescence device having a plurality of organic layers including a light emitting layer sandwiched between an anode and a cathode,
At least 1 layer of this organic layer contains the compound represented by following General formula (1), The organic electroluminescent element characterized by the above-mentioned.

[Wherein, R _{11 to} R ₁₈ , R _{21 to} R ₂₈ , R _{31 to} R ₃₆ and R _{40 to} R ₄₈ each represent a hydrogen atom or a substituent. X ₁ represents a simple bond or a linking group. However, at least one of R _{11 to} R ₁₈ and at least one of R _{21 to} R ₂₈ are each used for connection with any one of R _{31 to} R ₃₆ , and R _{11 to} R ₁₈ , R _{21 to} R are used. ₂₈ and at least one of R _{31 to} R ₃₆ and at least one of R _{40 to} R ₄₈ are used for connection with X ₁ . n represents an integer of 1 or more, and when n is 2 or more, the bonding positions may be the same or different. m represents an integer of 0 or more. When m is 2 or more, X ₁ may be the same or different. M represents an integer of 1 or more, and when M is 2 or more, X ₁ may be the same or different. ] In Formula _(1), any two of R 31 _{to R 36,} an organic electroluminescent device according to claim 1, characterized in that it is combined with _{R 16} and _{R 23.} In Formula _{(1), R 31} and _{R 33 An} organic electroluminescence device according to claim 1, characterized in that it is combined with _{R 16} and _{R 23.} The compound represented by the general formula (1) is represented by the following general formula (2), general formula (3), or general formula (4). The organic electroluminescent element of description.

_Wherein, R 11 _{to R 18} and _R 21 _{to R 28} are each the same meaning as _R 11 _{to R 18} and _R 21 _{to R 28} in the general formula (1). ] The organic electroluminescence element according to claim 1, wherein at least one of the organic layers is formed by a wet method. 6. The organic electroluminescence element according to claim 5, wherein one layer adjacent to at least one of the organic layers is formed by a wet method. The organic electroluminescence device according to claim 6, wherein two layers adjacent to at least one of the organic layers are formed by a wet method. The organic electroluminescence device according to claim 1, comprising a light emitting layer as a constituent layer, and the light emitting layer contains a compound represented by the general formula (1). . The organic electroluminescent element according to claim 8, wherein the light emitting layer contains a phosphorescent metal complex. The organic electroluminescent device according to claim 9, wherein the phosphorescent metal complex is a metal complex represented by the following general formula (5).

[In formula, P and Q represent a carbon atom or a nitrogen atom, and A1 represents the atomic group which forms an aromatic-hydrocarbon ring or an aromatic heterocyclic ring with PC. A2 represents an atomic group which forms an aromatic heterocycle with QN. P1-L1-P2 represents a bidentate ligand, and P1 and P2 each independently represent a carbon atom, a nitrogen atom, or an oxygen atom. L1 represents an atomic group that forms a bidentate ligand together with P1 and P2. j1 represents an integer of 1 to 3, j2 represents an integer of 0 to 2, and j1 + j2 is 2 or 3. M ₁ represents a transition metal element of Group 8 to Group 10 in the periodic table. ] The organic electroluminescent device according to claim 10, wherein A2 represented by the general formula (5) represents an atomic group forming a 5-membered aromatic heterocyclic ring. The organic electroluminescent device according to claim 10 or 11, wherein the phosphorescent metal complex is a metal complex represented by the following general formula (6).

[Wherein, Z represents a hydrocarbon ring group or a heterocyclic group. P and Q represent a carbon atom or a nitrogen atom, and A1 represents an atomic group that forms an aromatic hydrocarbon ring or an aromatic heterocycle together with PC. A3 represents -C ( _R01 ) = C ( _R02 )-, -N = C ( _R02 )-, -C ( _R01 ) = N- or -N = N-, and _R01 and _R02 represent Represents a hydrogen atom or a substituent. P1-L1-P2 represents a bidentate ligand, and P1 and P2 each independently represent a carbon atom, a nitrogen atom, or an oxygen atom. L1 represents an atomic group that forms a bidentate ligand together with P1 and P2. j1 represents an integer of 1 to 3, j2 represents an integer of 0 to 2, and j1 + j2 is 2 or 3. M ₁ represents a transition metal element of Group 8 to Group 10 in the periodic table. ] Z in the said General formula (6) is group represented by following General formula (7), The organic electroluminescent element of Claim 12 characterized by the above-mentioned.
General formula (7)
H _1- (Ar ₁ ) _n −
[In the formula, Ar ₁ represents a group derived from an aromatic hydrocarbon ring or a group derived from an aromatic heterocyclic ring, H ₁ represents a carrier transport unit, and n represents an integer of 0 to 10. ] The organic electroluminescence device according to any one of claims 9 to 13, wherein the phosphorescent metal complex is an Ir complex. The organic electroluminescent element according to claim 1, which emits white light. It has an organic electroluminescent element of any one of Claims 1-15, The illuminating device characterized by the above-mentioned. A display device comprising the organic electroluminescence element according to claim 1.

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