JP5652235B2 - Organic electroluminescence element, display device and lighting device - Google Patents

Description

  The present invention relates to an organic electroluminescence element, and a display device and a lighting device using the same.

  Conventionally, as a light-emitting electronic display device, there is an electroluminescence display (hereinafter referred to as ELD). 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 them, thereby excitons (exciton). And emits light by using light emission (fluorescence, phosphorescence, etc.) when the exciton is deactivated, and can emit light at a voltage of several volts to several tens of volts. Since it is a light-emitting type, it has a wide viewing angle, high visibility, and a thin-film type complete solid-state device, and therefore has attracted attention from the viewpoints of space saving and portability.

  However, for organic EL elements for practical use in the future, it is desired to develop organic EL elements that emit light with higher luminance and higher efficiency with lower power consumption.

  In response to the above problems, for example, a small amount of phosphor is doped into a stilbene derivative, a distyrylarylene derivative or a tristyrylarylene derivative to improve emission luminance, extend the lifetime of the device, and use 8-hydroxyquinoline aluminum complex as a luminescent host. There are known an element having an organic light-emitting layer doped with a small amount of phosphor, an element having an organic light-emitting layer doped with a quinacridone dye, using 8-hydroxyquinoline aluminum complex as a light-emitting host.

  However, as described above, when the emission from the excited singlet is used, the generation ratio of the singlet exciton and the triplet exciton is 1: 3. Therefore, the generation probability of the luminescent excited species is 25%. Since the light extraction efficiency is about 20%, the limit of the external extraction quantum efficiency (ηext) is set to 5%.

  However, since Princeton University reported on an organic EL device using phosphorescence emission from an excited triplet (Non-patent Document 1), research on materials that exhibit phosphorescence at room temperature has been active.

  When the excited triplet is used, the upper limit of the internal quantum efficiency is 100%, so that in principle, the luminous efficiency is four times that of the excited singlet, and there is a possibility that almost the same performance as a cold cathode tube can be obtained. For this reason, it is attracting attention as a lighting application.

  For example, many phosphorescent dopants have been investigated around iridium complexes or transition metal complexes such as platinum.

In addition, tris (2-phenylpyridine) iridium as a dopant, L ₂ Ir (acac) as a dopant, for example, (ppy) ₂ Ir (acac), tris (2- (p-tolyl) pyridine) iridium (Ir as a dopant) (Ptpy) ₃ ), excited triplets using tris (benzo [h] quinoline) iridium (Ir (bzq) ₃ ) and the like have also been studied (these metal complexes are generally called orthometalated iridium complexes). )

  Although these complexes are also shown below, they are called phosphorescent dopants because they are used after being dispersed and added in the light emitting layer together with the light emitting host (or simply called the host).

  Since the performance (emission efficiency, emission lifetime, emission color, etc.) of organic EL varies greatly depending not only on the dopant but also on the host, the development of both has been energetically performed.

  For example, in order to obtain high luminous efficiency, a hole transporting compound is used as a host for a phosphorescent compound, or various electron transporting materials are used as a host for a phosphorescent compound, and these are doped with a novel iridium complex. It is known to be used.

  In any method, by appropriately selecting the dopant and the host, the light emission brightness and light emission efficiency of the light emitting device are greatly improved compared to conventional devices because the emitted light is derived from phosphorescence. However, the light emission lifetime of the element has a problem that it is shorter than that of a conventional fluorescent element.

  In particular, in the case of a blue light-emitting element, the light emission lifetime is extremely shortened, and a blue dopant that satisfies all of the light emission efficiency, the light emission wavelength, and the light emission lifetime has not yet been found, and its creation is urgent. Along with the development of blue dopants, blue light-emitting hosts are also being developed extensively. In particular, carbazole derivatives are being considered as promising materials. In addition, various analyzes have been performed for improving the light emission lifetime. For example, in Non-Patent Document 2, a carbazole derivative host is analyzed, and the structure identification of a deteriorated product by LC-Mass indicates that the CN bond. Cleaved and carbazole-added compounds were detected.

  In addition, it is known that substituents are introduced not only at the 1,8-position but also at the 3,6-position of carbazole (Reference Patent Documents 1 and 2). During storage, it was found that these compounds were partially oriented or microcrystallized, resulting in problems such as an increase in driving voltage and a shortened emission lifetime.

JP 2005-093159 A JP 2008-195841 A

M.M. A. Baldo et al. , Nature, 395, 151-154 (1998) D. Y. Kondakov et al. , Journal of Applied Phisics (101) 024512 (2007).

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an organic electroluminescence element having a long light emission lifetime and a suppressed voltage increase during driving, and a display device and an illumination device using the organic electroluminescence element. That is.

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

1. An organic electroluminescence device comprising a compound having a partial structure represented by the following general formula (2) or general formula (3) .

(Wherein R _{1 to} R ₆ , R _{10 to} R ₁₄ , RA, RB, Rc, and Rd each independently represent a hydrogen atom or a substituent . At least one of RA and RB, or Rc, At least one of Rd is an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, a non-aromatic heterocyclic group, an aromatic heterocyclic group, a halogen atom, an alkoxyl group, or a cycloalkoxyl. Group, aryloxy group, alkylthio group, cycloalkylthio group, arylthio group, alkoxycarbonyl group, aryloxycarbonyl group, sulfamoyl group, ureido group, acyl group, acyloxy group, amide group, carbamoyl group, sulfinyl group, alkylsulfonyl group or Arylsulfonyl group, amino group, silyl group, trialkylboron Represents any of the groups selected triaryl containing group, a nitro group, a cyano group, a hydroxyl group, RA and RB together,. X represent the same substituent other than a hydrogen atom represents O, and S or -NRa .Ra is an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, a non-aromatic heterocyclic group or aromatic heterocyclic group table to.)

(In the formula, R _{1 to} R ₆ , R _{11 to} R ₁₆ , RA, RB and Rc each independently represent a hydrogen atom or a substituent, and at least one of RA, RB and Rc is an alkyl group. , Cycloalkyl group, alkenyl group, alkynyl group, aromatic hydrocarbon group, non-aromatic heterocyclic group, aromatic heterocyclic group, halogen atom, alkoxyl group, cycloalkoxyl group, aryloxy group, alkylthio group, cycloalkylthio group , Arylthio group, alkoxycarbonyl group, aryloxycarbonyl group, sulfamoyl group, ureido group, acyl group, acyloxy group, amide group, carbamoyl group, sulfinyl group, alkylsulfonyl group or arylsulfonyl group, amino group, silyl group, trialkyl Boron group, triaryl boron group, nitro group, cyano group, Represents any group selected from Dorokishiru groups, RA and RB together represent. X is O, is .Ra representing S or -NRa alkyl group the same substituents other than a hydrogen atom, a cycloalkyl group, an alkenyl group , an alkynyl group, an aromatic hydrocarbon group, a non-aromatic heterocyclic group or aromatic heterocyclic group table to.)

2 . The organic electroluminescent device according to the 1-emitting form of the organic electroluminescent device is characterized in that it is a phosphorescent.

3 . 3. The organic electroluminescence device as described in 1 or 2 above, wherein the emission color is blue.

4 . 4. The organic electroluminescence device according to any one of 1 to 3 , wherein the emission color is white.

5 . 5. A display device comprising the organic electroluminescence element according to any one of 1 to 4 above.

6 . 5. An illumination device comprising the organic electroluminescence element according to any one of 1 to 4 above.

  According to the present invention, it was possible to provide an organic electroluminescence element having a long light emission lifetime and a suppressed voltage increase during driving, and a display device and an illumination device using the organic electroluminescence element.

It is the schematic perspective view which showed an example of the structure of the display apparatus of this invention. It is the schematic perspective view which showed an example of the structure of the display part A shown in FIG. It is a schematic perspective view which shows an example of the illuminating device using the organic EL element of this invention. It is a schematic sectional drawing which shows an example of the illuminating device using the organic EL element of this invention.

  Hereinafter, although the form for implementing this invention is demonstrated in detail, this invention is not limited to these.

<< Organic EL element (Organic electroluminescence element) >>
The organic EL element of the present invention will be described.

  It is important for the inventor to design the molecule with reference to the results of Non-Patent Document 2 and to three-dimensionally protect the C—N bond of the carbazole skeleton as a light-emitting host. By introducing a substituent at the 8th position or by introducing a substituent at the 2nd and 6th positions of the benzene ring, the generation of C—N bond cleavage can be suppressed, and the device lifetime is improved and the voltage during driving is increased. It is as soon as the present invention has been found that it leads to suppression. In addition, by removing one of the carbazole positions 3 and 6 and breaking the symmetry, orientation and microcrystallization can be suppressed, which is effective in improving device life and suppressing voltage rise during driving. It was found to be a preferred embodiment.

  The organic EL device of the present invention is characterized by containing a compound represented by the general formula (1).

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

  The compound represented by the general formula (1) is preferably used in the light emitting layer of the organic EL device of the present invention, and particularly preferably used as a host in the light emitting layer. The constituent layers and the host of the organic EL element of the present invention will be described in detail later.

In the general formula (1), R _{1 to} R ₉ , RA, RB, Rc, and Rd each independently represent a hydrogen atom or a substituent, and at least one of RA and RB, or Rc, Rd At least one of them is a substituent.

Substituents are alkyl groups, cycloalkyl groups, alkenyl groups, alkynyl groups, aromatic hydrocarbon groups, non-aromatic heterocyclic groups, aromatic heterocyclic groups, halogen atoms, alkoxyl groups, cycloalkoxyl groups, aryloxy groups, alkylthio groups. Group, cycloalkylthio group, arylthio group, alkoxycarbonyl group, aryloxycarbonyl group, sulfamoyl group, ureido group, acyl group, acyloxy group, amide group, carbamoyl group, sulfinyl group, alkylsulfonyl group or arylsulfonyl group, amino group, It is any group selected from a silyl group, a trialkyl boron group, a triaryl boron group, a nitro group, a cyano group, and a hydroxyl group. R _{1 to} R ₉ may form a condensed ring together with the benzene ring.

  Specifically, examples of the substituent in the general formula (1) include an alkyl group (for example, methyl group, ethyl group, propyl group, isopropyl group, (t) butyl group, pentyl group, hexyl group, octyl group, dodecyl group). , Tridecyl group, tetradecyl group, pentadecyl group, etc.), cycloalkyl group (eg, cyclopentyl group, cyclohexyl group, etc.), alkenyl group (eg, vinyl group, allyl group, etc.), alkynyl group (eg, propargyl group, etc.), aromatic Group hydrocarbon group (also referred to as aryl group, such as 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, etc.), non-aromatic heterocyclic group (for example, epoxy) Cy ring, aziridine ring, thiirane ring, oxetane ring, azetidine ring, thietane ring, tetrahydrofuran ring, dioxolane ring, pyrrolidine ring, pyrazolidine ring, imidazolidine ring, oxazolidine ring, tetrahydrothiophene ring, sulfolane ring, thiazolidine ring, ε-caprolactone Ring, ε-caprolactam ring, piperidine ring, hexahydropyridazine ring, hexahydropyrimidine ring, piperazine ring, morpholine ring, tetrahydropyran ring, 1,3-dioxane ring, 1,4-dioxane ring, trioxane ring, tetrahydrothiopyran Ring, thiomorpholine ring, thiomorpholine-1,1-dioxide ring, pyranose ring, diazabicyclo [2,2,2] -octane ring), aromatic heterocyclic group (pyridyl group, pyrimidinyl group, furyl group, pyrrolyl group) , Imida Ryl group, benzoimidazolyl group, pyrazolyl group, pyrazinyl group, triazolyl group (for example, 1,2,4-triazol-1-yl group, 1,2,3-triazol-1-yl group, etc.), oxazolyl group, benzooxa Zolyl, thiazolyl, isoxazolyl, isothiazolyl, furazanyl, thienyl, quinolyl, benzofuryl, dibenzofuryl, benzothienyl, dibenzothienyl, indolyl, carbazolyl, carbolinyl, diazacarbazolyl Group (in which one of the carbon atoms constituting the carboline ring of the carbolinyl group is replaced by a nitrogen atom), a quinoxalinyl group, a pyridazinyl group, a triazinyl group, a quinazolinyl group, a phthalazinyl group, etc.), a halogen atom (for example, chlorine Atom, bromine atom, iodine atom, Nitrogen atom, etc.), alkoxyl group (eg, methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.), cycloalkoxyl group (eg, cyclopentyloxy group, cyclohexyl) Oxy group etc.), aryloxy group (eg phenoxy group, naphthyloxy group etc.), alkylthio group (eg methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group etc.), cycloalkylthio Groups (for example, cyclopentylthio group, cyclohexylthio group, etc.), arylthio groups (for example, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl groups (for example, methyloxycarbonyl group, ethyloxycarbonyl group, butyl group) Xycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (eg, aminosulfonyl group, methylaminosulfonyl group, dimethyl) Aminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), ureido group ( For example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido Group, naphthylureido group, 2-pyridylaminoureido group, etc.), acyl group (for example, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group) Group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (for example, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.) ), Amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, Rohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethyl) Aminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group Group), sulfinyl group (for example, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfuryl group) Finyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc.), alkylsulfonyl group or arylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group) Cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (for example, amino group, ethylamino group, dimethylamino group, butylamino group) , Cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridylamino group, etc.), silyl group (for example, triphenylsilyl group, Limethylsilyl group, etc.), trialkylboron group (eg, trimethylboron group, triethylboron group, tri-t-butyl group, etc.), triarylboron group (eg, triphenylboron group, trixylylboron group, trimesitylboron group) , Trinaphthalene boron group, tripyridyl boron group), nitro group, cyano group, hydroxyl group and the like. These groups may be further substituted with the above substituents, or they may be condensed with each other to form a ring.

  Preferably, in the compound having a partial structure represented by the general formula (1), at least one of Rc and Rd is the substituent.

In general formula (1), one of R ₂ or R ₅ is an aromatic hydrocarbon group, a non-aromatic heterocyclic group, or an aromatic heterocyclic group, and the other one is a hydrogen atom. It is preferable at the point which suppresses. Specifically, an aromatic hydrocarbon group is preferable.

  Preferably, the compound having a partial structure represented by the general formula (1) is a compound having a partial structure represented by the general formula (2).

In the general formula (2), R _{1 to} R ₆ , R _{10 to} R ₁₄ , RA, RB, Rc, and Rd each independently represent a hydrogen atom or a substituent, and at least one of RA and RB, Alternatively, at least one of Rc and Rd is a substituent, and X represents O, S, or -NRa. Ra represents an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, a non-aromatic heterocyclic group, or an aromatic heterocyclic group, and the substituent is synonymous with the substituent of the general formula (1). is there.

  Preferably, the compound having a partial structure represented by the general formula (1) is a compound having a partial structure represented by the general formula (3).

In General Formula (3), R _{1 to} R ₆ , R _{11 to} R ₁₆ , RA, RB, and Rc each independently represent a hydrogen atom or a substituent, and at least one of RA, RB, and Rc is substituted. And X represents O, S or —NRa. Ra represents an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, a non-aromatic heterocyclic group, or an aromatic heterocyclic group, and the substituent is synonymous with the substituent of the general formula (1). is there.

  In the general formula (2) and the general formula (3), X is particularly preferably a nitrogen atom or an oxygen atom.

Preferably, among R _{1 to} R ₆ in the general formula (1), R ₂ or R ₅ is an aromatic hydrocarbon group, a non-aromatic heterocyclic group, or an aromatic heterocyclic group, and the R _{1 to} R The remainder of ₆ is a hydrogen atom.

  Specific examples of the compound according to the present invention are shown below, but the present invention is not limited thereto.

  The compound having a partial structure represented by the general formula (1) according to the present invention is, for example, Organic Letter, vol. 16, 2579-2581 (2001), Inorganic Chemistry, Vol. 30, No. 8, 1685-1687 (1991), J. Am. Am. Chem. Soc. , 123, 4304 (2001), Inorganic Chemistry, Vol. 40, No. 7, 1704-1711 (2001), Inorganic Chemistry, Vol. 41, No. 12, 3055-3066 (2002) , New Journal of Chemistry. 26, 1171 (2002), Organic Letter, vol. 3, pp. 415 to 418 (2006), and further by referring to methods such as references described in these documents.

  Below, an example of the specific synthesis | combining method of the compound which has a partial structure represented by General formula (1) is shown.

(Synthesis of Exemplified Compound 1)
Exemplified Compound 1 was synthesized according to the following synthesis flow.

(Synthesis of 3,6-dinitrocarbazole)
To a 300 ml three-head flask, 10 g of carbazole and 100 ml of nitric acid were added, heated to 90 ° C. and stirred for 2 hours.

  After cooling the reaction solution, the reaction solution was poured into ice water. The precipitated crystals were filtered, and the crystals were purified by silica gel chromatography (developing solution hexane: ethyl acetate = 10: 1) to obtain 9.5 g of the desired product.

(Synthesis of 1,8-dibromo-3,6-dinitrocarbazole)
In a 300 ml three-head flask, 9 g of 3,6-dinitrocarbazole and 50 ml of sulfuric acid were added and dissolved. To this solution, 3.3 ml of bromine was added dropwise, then heated to 90 ° C. and stirred for 2 hours. After cooling the reaction solution, the reaction solution was poured into ice water. The precipitated crystals were filtered, and the precipitate was purified by silica gel chromatography (developing solution hexane: ethyl acetate = 10: 1) to obtain 5.2 g of the desired product.

(Synthesis of 1,8-dibromo-3,6-diaminocarbazole)
After dissolving 5 g of 1,8-dibromo-3,6-dinitrocarbazole in 100 ml of THF and adding 0.5 g of Pd / C, a hydrogenation reaction was performed at room temperature for 5 hours.

  After completion of the reaction, Pd / C was filtered and concentrated with an evaporator. This residue was purified by silica gel chromatography (developing solution hexane: ethyl acetate = 4: 1) to obtain 2.3 g of the desired product.

(Synthesis of 1,8-dibromocarbazole)
To a 100 ml three-headed flask, 1.5 g of 1,8-dibromo-3,6-diaminocarbazole, 12 ml of water, 10 ml of EtOH and 2 ml of HCl were added and stirred. The solution was cooled to 10 ° C., a solution obtained by dissolving 7 g of sodium nitrite in 10 ml of water was added dropwise, and the mixture was stirred at 10 ° C. for 30 minutes. Then, 10 ml of H3PO2 was added and further stirred at 10 ° C. for 4 hours.

  After completion of the reaction, methylene chloride was added thereto. This solution was transferred to a separatory funnel, the organic layer was washed with water, dried over magnesium sulfate, filtered through magnesium sulfate, and concentrated to obtain 1 g of the desired product.

(Synthesis of 1,8-diphenylcarbazole)
To a three-headed 100 ml flask, 1 g of 1,8-dibromocarbazole, 1.5 g of phenylboronic acid, 20.1 g of pd (dba), 0.1 g of dppf, and 1.8 g of potassium carbonate were added, and 30 ml of dimethoxyethane and 10 ml of water were further added. . The mixture was heated to reflux for 6 hours in a nitrogen stream.

  After completion of the reaction, the mixture was transferred to a separatory funnel, water and ethyl acetate were added, and the organic layer was taken out. The organic layer was further washed with water, dried over magnesium sulfate, filtered through magnesium sulfate, and the filtrate was concentrated. This residue was purified by silica gel chromatography (developing solution hexane: ethyl acetate = 8: 1) to obtain 1.1 g of the desired product.

(Synthesis of 1)
To a three-headed 100 ml flask, 0.6 g of 1,8-diphenylcarbazole, 0.15 g of 1,3-diiodobenzene, 0.12 g of copper powder and 0.7 g of potassium carbonate were added, and 30 ml of dimethylacetamide was added. Heating was performed at an internal temperature of 135 ° C. for 6 hours under nitrogen flow.

  After completion of the reaction, the mixture was transferred to a separatory funnel, water and ethyl acetate were added, and the organic layer was taken out. The organic layer was further washed with water, dried over magnesium sulfate, filtered through magnesium sulfate, and the filtrate was concentrated. This residue was purified by silica gel chromatography (developing solution hexane: ethyl acetate = 8: 1) to obtain 0.3 g of the desired product.

<< Constituent layers of organic EL elements >>
Next, the constituent layers of the organic EL element of the present invention will be described. In this invention, although the preferable specific example of the layer structure of an organic EL element 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 (vi) anode // hole transport layer / anode buffer layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode (vii) anode / anode Buffer layer / hole transport layer / light emitting layer / electron transport layer / cathode buffer layer / cathode The light emitting layer may form a unit to form a light emitting layer unit. Further, a non-light emitting intermediate layer may be provided between the light emitting layers, and the intermediate layer may include a charge generation layer. The organic EL element of the present invention preferably emits white light and is preferably a lighting device using these.

  Hereinafter, each layer which comprises the organic EL element of this invention is demonstrated.

《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 with a single layer or a plurality of layers.

  An electron transport material (including a hole blocking material and an electron injection material) used for the electron transport layer only needs to have a function of transmitting electrons injected from the cathode to the light emitting layer. Can be selected and used from conventionally known compounds.

  Examples of conventionally known materials used for the electron transport layer (hereinafter referred to as electron transport materials) include heterocyclic tetracarboxylic acid anhydrides such as nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, naphthalene perylene, And azacarbazole derivatives including carbodiimide, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives, carboline derivatives, and the like.

  Here, the azacarbazole derivative refers to one in which one or more carbon atoms constituting the carbazole ring are replaced with a nitrogen atom.

  Furthermore, in the 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.

  It is also possible to use a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain.

  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 the terminal substituted with an alkyl group or a sulfonic acid group can also be used as the electron transport material.

  Further, similarly to the hole injection layer and the hole transport layer, inorganic semiconductors such as n-type-Si and n-type-SiC can also be used as the electron transport material.

  The electron transport layer is made of an electron transport material such as a vacuum deposition method, a wet method (also called a wet process, such as a spin coating method, a casting method, a die coating method, a blade coating method, a roll coating method, an ink jet method, a printing method, It is preferable to form the film by a coating method, a curtain coating method, an LB method (such as Langmuir-Blodgett method)).

  The method for forming the constituent layers of the organic EL element will be described in detail in the section of the method for manufacturing the organic EL element.

  Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, about 5 nm-5000 nm, Preferably it is 5 nm-200 nm. This 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.

  Hereinafter, although the specific example of the conventionally well-known compound (electron transport material) preferably used for formation of the electron carrying layer of the organic EL element of this invention is given, this invention is not limited to these.

  In addition, the compound represented by the following general formula (R-1) is more preferably used for forming the electron transport layer of the organic EL device of the present invention.

  In the general formula (R-1), Rr represents an alkyl group, a cycloalkyl group, an aromatic hydrocarbon group, or an aromatic heterocyclic group. Rs represents a substituent, and Rs is preferably an alkyl group, a cycloalkyl group, an aromatic hydrocarbon group or an aromatic heterocyclic group, and particularly preferably an aromatic hydrocarbon group or An aromatic heterocyclic group. z represents an integer of 1 to 7.

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

  The light emitting layer according to the present invention preferably contains a compound having a partial structure represented by the general formula (1) according to the present invention as a light emitting host.

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

  For the formation of the light emitting layer, a light emitting dopant or a light emitting host, which will be described later, is used, for example, a vacuum deposition method, a wet coating method (also referred to as a wet process, for example, a spin coating method, a casting method, a die coating method, a blade coating method, a roll coating method). , An inkjet method, a printing method, a spray coating method, a curtain coating method, an LB method (Langmuir Brodgett method) and the like.

  In order to include the compound represented by the general formula (1) according to the present invention in the light emitting layer, the light emitting layer is preferably formed using the wet coating method.

  The light emitting layer of the organic EL device of the present invention preferably contains a light emitting dopant (also referred to as a dopant) and a light emitting host.

(Light-emitting host (also called host))
The light emitting host used in the present invention is preferably a compound having a partial structure represented by the general formula (1).

  In this invention, it is preferable that the light emission form of the organic electroluminescent element which concerns on this invention is phosphorescence.

  In the present invention, the light-emitting host has a mass ratio of 20% or more of the compounds contained in the light-emitting layer and a phosphorescence quantum yield of phosphorescence at a room temperature (25 ° C.) of 0. Less than one compound. 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.

  As the light-emitting host, the above-described light-emitting hosts may be used alone or in combination of two or more. By using a plurality of types of light-emitting hosts, the movement of charges can be adjusted, and the organic EL element can be made highly efficient. Moreover, it becomes possible to mix different light emission by using multiple types of the compound containing the partial structure represented by the said General formula (1), and the light emission dopant mentioned later, and can obtain arbitrary luminescent colors by this. it can.

  The luminescent host that can be used in combination is not particularly limited in terms of structure, but typically carbazole derivatives, triarylamine derivatives, aromatic borane derivatives, nitrogen-containing heterocyclic compounds, thiophene derivatives, furan derivatives, oligoarylene compounds, etc. Or a carboline derivative or a diazacarbazole derivative (herein, a diazacarbazole derivative means that at least one carbon atom of a hydrocarbon ring constituting a carboline ring of a carboline derivative is substituted with a nitrogen atom) And the like).

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

  As the known light-emitting host that may be used in combination, 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) is preferable.

  Specific examples of known light-emitting hosts 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, etc. (Light emitting dopant)
The luminescent dopant will be described.

  As the light-emitting dopant, a fluorescent dopant (also referred to as a fluorescent compound) or a phosphorescent dopant (also referred to as a phosphorescent compound) can be used.

(Phosphorescent dopant)
The phosphorescent dopant will be described.

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

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

  There are two types of light emission of the phosphorescent dopant in principle. One is the recombination of carriers on the light emitting host to which carriers are transported to generate an excited state of the light emitting host, and this energy is transferred to the phosphorescent dopant. Energy transfer type to obtain light emission from the phosphorescent dopant, and the other is that the phosphorescent dopant becomes a carrier trap, carrier recombination occurs on the phosphorescent dopant, and light emission from the phosphorescent dopant compound is obtained. However, in any case, the excited state energy of the phosphorescent dopant is required to be lower than the excited state energy of the light-emitting host.

  As the light emitting dopant according to the organic EL device of the present invention, compounds described in the following patent publications can be used. Two or more kinds may be used in combination.

  For example, International Publication No. 00/70655, JP 2002-280178, JP 2001-181616, JP 2002-280179, JP 2001-181617, JP 2002-280180, JP 2001-247859 A, JP 2002-299060 A, JP 2001-313178 A, JP 2002-302671 A, JP 2001-345183 A, JP 2002-324679 A, International Publication. No. 02/15645, JP 2002-332291 A, JP 2002-50484 A, JP 2002-332292 A, JP 2002-83684 A, JP 2002-540572 A, JP 2002-2002 A. No. 117978, Japanese Patent Application Laid-Open No. 2002-33858 JP, JP-A-2002-170684, JP-A-2002-352960, WO01 / 93642, JP-A-2002-50483, JP-A-2002-1000047, JP-A-2002-173684. JP-A-2002-359082, JP-A-2002-175484, JP-A-2002-363552, JP-A-2002-184582, JP-A-2003-7469, JP-A-2002-525808, JP 2003-7471, JP 2002-525833, JP 2003-31366, JP 2002-226495, JP 2002-234894, JP 2002-2335076, JP 2002 No. 2411751, JP 2001-319779 A. JP, 2001-319780, 2002-62824, 2002-100474, 2002-203679, 2002-343572, 2002-203678, etc. It is.

(Fluorescent dopant)
As fluorescent dopants (also referred to as fluorescent compounds), coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, Examples include perylene dyes, stilbene dyes, polythiophene dyes, rare-earth complex phosphors, and compounds having a high fluorescence quantum yield typified by laser dyes.

  In addition, the light-emitting dopant may be used in combination of a plurality of types of compounds, or may be a combination of phosphorescent dopants having different structures or a combination of a phosphorescent dopant and a fluorescent dopant.

  Here, although the specific example of a conventionally well-known light emission dopant is given, this invention is not limited to these.

《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 is formed by thinning the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. Can do.

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

  Alternatively, a hole transport layer having a high p property doped with impurities can be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, 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.

  Hereinafter, although the specific example of the positive hole transport material preferably used for formation of the positive hole transport layer of the organic EL element of this invention is given, this invention is not limited to these.

<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 having a function of transporting electrons and a very small ability to transport holes. By blocking the holes, the probability of recombination of electrons and holes can be improved.

  Moreover, the structure of the above-mentioned electron carrying layer can be used as a hole-blocking layer as needed.

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

  In the hole blocking layer, the carbazole derivative or azacarbazole derivative mentioned above as the light-emitting host (here, the azacarbazole derivative is one in which one or more carbon atoms constituting the carbazole ring are replaced with nitrogen atoms). Preferably).

  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.

  Further, 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 light emitting host of the shortest wave emitting layer.

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

  (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 As a value (eV unit converted value) calculated by performing structure 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 holes. By blocking electrons, the recombination probability of electrons and holes can be improved.

  Moreover, the structure of the above-mentioned hole transport layer can be used as an electron blocking layer as needed. In the present invention, the thickness of the hole blocking layer and the electron blocking layer is preferably 3 nm to 100 nm, and more preferably 3 nm to 30 nm.

<< Injection layer: electron injection layer (cathode buffer 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, 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 present.

  The injection layer is a layer provided between the electrode and the organic layer in order to lower the driving voltage and improve the light emission luminance. “The organic EL element and its industrialization front line (November 30, 1998, NT. The details are described in Chapter 2, “Electrode Materials” (pages 123 to 166) of the second edition of “S. Co., Ltd.”. The hole injection layer (anode buffer layer) and the electron injection layer (cathode buffer layer) There is.

  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, alkali metal compound buffer layer typified by lithium fluoride, sodium fluoride and potassium fluoride, alkaline earth metal compound buffer layer typified by magnesium fluoride, and aluminum oxide And an oxide buffer layer. 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.

  In addition, the materials used for the anode buffer layer and the cathode buffer layer can be used in combination with other materials. For example, they can be used in a mixture in a hole transport layer or an electron transport layer. .

"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) that can form a transparent conductive film may be used. The anode may be formed by depositing these electrode materials by a method such as vapor deposition or sputtering, and a desired shape pattern may be formed by a photolithography method, or when pattern accuracy is not so high (about 100 μm or more), A pattern may be formed through a mask having a desired shape at the time of vapor deposition or sputtering of the electrode material.

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

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

"cathode"
On the other hand, a metal having a small work function (4 eV or less) (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof are used as an electrode material for the cathode.

Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like.

Among these, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred.

  The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually preferably in the range of 10 nm to 5 μm, more preferably in the range of 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 by the film thickness of 1 nm-20 nm to a cathode, the transparent or semi-transparent cathode can be produced by producing the electroconductive transparent material quoted by description of the anode on it, By applying this, an element in which both the anode and the cathode are transmissive can be manufactured.

"substrate"
The substrate that can be used in the organic EL device of the present invention is not particularly limited in kind, such as glass and plastic, and may be transparent or opaque. When extracting light from the substrate side, the substrate is preferably transparent.

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

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

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

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

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

  Examples of the opaque substrate include a metal plate such as aluminum and stainless steel, a film, an opaque resin substrate, a ceramic substrate, and the like.

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

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

<< Method for Manufacturing Organic EL Element >>
As an example of a method for producing an organic EL element, an organic EL composed of an anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer (electron injection layer) / cathode A method for manufacturing the element will be described.

  First, a thin film made of a desired electrode material, for example, an anode material, is formed on a suitable substrate so as to have a thickness of 1.0 μm or less, preferably 10 nm to 200 nm, and an anode is manufactured.

  Next, a thin film containing organic compounds such as a hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, an electron transport layer, and a cathode buffer layer, which are element materials, is sequentially formed on the anode.

  In the organic EL device of the present invention, the light emitting layer when the compound represented by the general formula (1) according to the present invention is used for the light emitting layer, and the cathode and the electron transport layer adjacent to the cathode are applied by a wet method. -It is preferable to form a film.

  Examples of wet coating methods include spin coating, casting, die coating, blade coating, roll coating, ink jet, printing, spray coating, curtain coating, and LB, but a precise thin film is formed. From the viewpoint of possible and high productivity, a method with high roll-to-roll method suitability such as a die coating method, a roll coating method, an ink jet method, and a spray coating method is preferable. Different film forming methods may be applied for each layer.

  Examples of the liquid medium for dissolving or dispersing the organic EL material according to the present invention include ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, halogenated hydrocarbons such as dichlorobenzene, toluene, xylene, and mesitylene. Aromatic hydrocarbons such as cyclohexylbenzene, aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane, and organic solvents such as dimethylformamide (DMF) and dimethylsulfoxide (DMSO) can be used.

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

  After sequentially forming these layers, a thin film made of a cathode material is formed thereon so as to have a thickness of 1 μm or less, preferably in the range of 50 nm to 200 nm, and a desired organic EL element is obtained by providing a cathode. can get.

  Further, the order can be reversed, and the cathode, cathode buffer layer, electron transport layer, hole blocking layer, light emitting layer, hole transport layer, hole injection layer, and anode can be formed 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 V 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.

  The organic EL device of the present invention is preferably produced from the hole injection layer to the cathode consistently by a single evacuation, but may be taken out halfway and subjected to different film forming methods. At that time, it is preferable to perform the work in a dry inert gas atmosphere.

<Sealing>
As a sealing means used for this invention, the method of adhere | attaching a sealing member, an electrode, and a board | 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 organic EL element can be thinned.

Furthermore, the polymer film has a oxygen permeability measured by a method according to JIS K 7126-1987 of 1 × 10 ⁻³ ml / (m ² · 24 h · MPa) or less, and a method according to JIS K 7129-1992. It is preferable that the water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) measured in (1) is 1 × 10 ⁻³ g / (m ² · 24 h) or less.

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

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

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

  In addition, it is also possible to suitably form an inorganic or organic layer as a sealing film by covering the electrode and the organic layer on the outer side of the electrode facing the substrate with the organic layer interposed therebetween, and in contact with the substrate. In this case, the material for forming the film may be any material that has a function of suppressing intrusion of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like may be used. it can.

  Further, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of organic materials.

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

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

  Examples of the hygroscopic compound include metal oxides (for example, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide) and sulfates (for example, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate). Etc.), metal halides (eg calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide etc.), perchloric acids (eg perchloric acid) Barium, magnesium perchlorate, etc.), among others, 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 substrate with the organic layer interposed therebetween or on the sealing film. In particular, when the sealing is performed by the sealing film, the mechanical strength is not necessarily high, and thus it is preferable to provide such a protective film and a protective plate. As a material that can be used for this, the same glass plate, polymer plate / film, metal plate / film, and the like used for the sealing can be used, but the polymer film is light and thin. Is preferably used.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are arranged two-dimensionally 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.

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

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

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

Further, 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 when the 2 ° viewing angle front luminance is measured by the above method. = 0.33 ± 0.07 and Y = 0.33 ± 0.1.

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

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

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

  The configuration of the organic EL element provided in the display device is selected from the above-described configuration examples of the organic EL element as necessary. Moreover, the manufacturing method of an organic EL element is as having shown to the one aspect | mode of manufacture of the organic EL element of said invention.

  In the case of applying a DC voltage to the obtained multicolor display device, light emission can be observed by applying a voltage of about 2V to 40V with the positive polarity of the anode and the negative polarity of the cathode. Further, even when a voltage is applied with the opposite polarity, no current flows and no light emission occurs.

  Further, when an AC voltage is applied, light is emitted only when the anode is in the + state and the cathode is in the-state. The alternating current waveform to be applied may be arbitrary.

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

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

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

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

  FIG. 1 is a schematic perspective view showing an example of the configuration of a display device composed of the organic EL element of the present invention, which displays image information by light emission of the organic EL element, for example, a schematic diagram of a display such as a mobile phone. FIG.

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

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

  FIG. 2 is a schematic perspective view showing an example of the configuration of the display unit A shown in FIG. The display unit A includes a wiring unit including a plurality of scanning lines 5 and data lines 6, a plurality of pixels 3 and the like on a substrate. The main members of the display unit A will be described below.

  FIG. 2 shows a case where the light 7 emitted from the pixel 3 is extracted in the direction of the white arrow (downward).

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

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

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

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

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

  Moreover, you may use for the said use by making a laser oscillation. Furthermore, the organic EL element of the present invention may be used as a kind of lamp for illumination or exposure light source, a projection device for projecting an image, or a type for directly viewing a still image or a moving image. It may be used as a display device (display).

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

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

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

  It is only necessary to provide a mask only when forming a light emitting layer, a hole transport layer, an electron transport layer, etc., and simply arrange them separately by coating with the mask. Since other layers are common, patterning of the mask etc. is unnecessary, In addition, for example, an electrode film can be formed by a vapor deposition method, a cast method, a spin coating method, an ink jet method, a printing method, or the like, and productivity is also improved.

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

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

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

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

  FIG. 3 is a schematic perspective view showing an example of a lighting device using the organic EL element of the present invention. The organic EL element 101 of the present invention is covered with a glass cover 102 (in addition, the sealing operation with the glass cover is a glove box (purity 99.999 in a nitrogen atmosphere without bringing the organic EL element 101 into contact with the atmosphere). % In a high purity nitrogen gas atmosphere).

  FIG. 4 is a schematic cross-sectional view showing an example of a lighting device using the organic EL element of the present invention. In FIG. 4, 105 denotes a cathode, 106 denotes an organic EL layer, and 107 denotes a glass substrate with a transparent electrode. The glass cover 102 is filled with nitrogen gas 108 and a water catching agent 109 is provided.

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

Example 1
<< Production of organic EL element >>
[Production of Organic EL Element 1-1]
This ITO transparent electrode is provided after patterning on a substrate (NH45 manufactured by NH Techno Glass) on which a 100-nm-thick ITO (indium tin oxide) film is formed on a glass substrate of 100 mm × 100 mm and a thickness of 1.1 mm. The transparent substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and UV ozone cleaning was performed for 5 minutes.

This transparent substrate is fixed to a substrate holder of a commercially available vacuum vapor deposition apparatus. Meanwhile, 200 mg of α-NPD is placed in a molybdenum resistance heating boat, and 200 mg of Comparative 1 is placed in another molybdenum resistance heating boat as a luminescent host. 200 mg of BAlq was put into a molybdenum resistance heating boat, 100 mg of D-26 was added as a dopant to another molybdenum resistance heating boat, and 200 mg of Alq ₃ was put into another molybdenum resistance heating boat, which was attached to a vacuum deposition apparatus. .

Next, after reducing the vacuum tank to 4 × 10 ⁻⁴ Pa, the above-mentioned resistance heating boat containing α-NPD was heated by heating, and deposited on the transparent substrate at a deposition rate of 0.1 nm / second. A 40 nm hole transport layer was provided.

  Next, the resistance heating boat containing Comparative 1 and D-26 was energized and heated, and co-deposited on the hole transport layer at a deposition rate of 0.2 nm / second and 0.012 nm / second, respectively. A light emitting layer having a thickness of 40 nm was formed. In addition, the substrate temperature at the time of vapor deposition was room temperature.

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

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

  Then, 0.5 nm of lithium fluoride and 110 nm of aluminum were vapor-deposited, the cathode was formed, and the organic EL element 1-1 was produced.

  After the production, the non-light emitting surface of the organic EL element 1-1 is covered with a glass case, a 300 μm thick glass substrate is used as a sealing substrate, and an epoxy photo-curing adhesive (Toagosei Co., Ltd.) is used as a sealing material around the periphery. Lax Track LC0629B) is applied, and this is overlaid on the cathode and brought into close contact with the transparent substrate, irradiated with UV light from the glass substrate side, cured, and sealed, as shown in FIGS. An illumination device having the structure as shown was formed.

[Production of Organic EL Elements 1-2 to 1-20]
In the production of the organic EL element 1-1, except that the light emitting host used for forming the light emitting layer was changed from Comparative 1 to the exemplified compound according to the present invention as described in Table 1, respectively, Organic EL elements 1-2 to 1-20 were produced.

  In addition, the detail of the compound used for preparation of the organic EL elements 1-1 to 1-20 is as follows.

<< Evaluation of organic EL elements >>
The following evaluation was performed about the produced said organic EL elements 1-1 to 1-20.

(Evaluation of luminous efficiency: Measurement of external extraction quantum efficiency)
Each organic EL element is caused to emit light at room temperature (about 23 ° C. to 25 ° C.) under a constant current condition of ^2.5 mA / cm ² , and the light emission luminance (L) [cd / m ² ] immediately after the start of light emission is measured. Thus, the external extraction quantum efficiency (η) was calculated. In addition, CS-1000 (made by Konica Minolta Sensing) was used for the measurement of light emission luminance.

  Luminous efficiency (external extraction quantum efficiency) was expressed as a relative value with the organic EL element 1-1 as 100.

(Measurement of luminous lifetime)
The time required for the organic EL device to continuously emit light at room temperature (about 23 ° C. to 25 ° C.) under a constant current condition of ^2.5 mA / cm ² and to be half the initial luminance (half life) τ1 / 2) was measured and used as a measure of the light emission lifetime. In addition, the light emission lifetime was represented by the relative value which sets the organic EL element 1-1 to 100.

(Measurement of voltage rise during driving)
With respect to the organic EL element, the driving voltage when emitting light under a constant current condition of ^2.5 mA / cm ² and the driving voltage when the emission luminance is 50% are measured, and ΔV = (initial voltage−luminance at 50%). Voltage) was measured and indicated as a relative value to the comparative sample. In Table 1, it represented with the relative value which sets (DELTA) V of the organic EL element 1-1 to 100. A lower value is preferable because there is less voltage increase during driving.

  The results obtained as described above are shown in Table 1.

  As is clear from the results shown in Table 1, it can be seen that the organic EL device of the present invention has a longer light emission lifetime than the comparative example, and can emit light with little voltage increase ΔV during driving.

Example 2
<< Production of organic EL element >>
[Production of Organic EL Element 2-1]
After patterning on a substrate (NH-Techno Glass Co., Ltd. NA-45) formed by depositing ITO (indium tin oxide) at a thickness of 100 nm on a glass substrate of 100 mm × 100 mm and a thickness of 1.1 mm as an anode, The transparent substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  On this transparent substrate, using a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water, 3000 rpm, 30 A thin film was formed by spin coating under the conditions of seconds, and then dried at 200 ° C. for 1 hour to provide a 20 nm-thick hole transport layer.

  This substrate was transferred to a nitrogen atmosphere, and a solution of 3 mg of hole transport material HT-24 and 40 mg of hole transport material HT-26 dissolved in 10 ml of toluene on the hole transport layer at 1500 rpm for 30 seconds. A thin film was formed by spin coating on the hole transport layer under conditions. Further, ultraviolet light was irradiated for 180 seconds to carry out photopolymerization and crosslinking, thereby forming a second hole transport layer having a thickness of about 20 nm.

  On this second hole transport layer, spin coating method was performed at 600 rpm for 30 seconds using a solution in which 100 mg of Comparative 1 as a light emitting host and 10 mg of D-26 as a dopant were dissolved in 10 ml of toluene. A thin film was formed. It vacuum-dried at 60 degreeC for 1 hour, and was set as the light emitting layer with a film thickness of about 70 nm.

  Next, a thin film was formed on the light emitting layer by spin coating using a solution obtained by dissolving 50 mg of ET-10 in 10 ml of butanol at 1000 rpm for 30 seconds. Furthermore, it vacuum-dried at 60 degreeC for 1 hour, and was set as the electron carrying layer with a film thickness of about 30 nm.

Subsequently, this substrate was fixed to a substrate holder of a vacuum deposition apparatus, and after the vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa, lithium fluoride was deposited to 0.4 nm and aluminum was deposited to 110 nm as a cathode buffer layer. A cathode was formed, and an organic EL element 2-1 was produced.

  After the production, the non-light-emitting surface of the organic EL element 2-1 is covered with a glass case, a 300 μm thick glass substrate is used as a sealing substrate, and an epoxy photo-curing adhesive (Toagosei Co., Ltd.) is used as a sealant around the periphery. Lax Track LC0629B) is applied, and this is overlaid on the cathode and brought into close contact with the transparent substrate, irradiated with UV light from the glass substrate side, cured, and sealed, as shown in FIGS. A lighting device as shown was formed.

[Production of Organic EL Elements 2-2 to 2-20]
In the production of the organic EL device 2-1, the light-emitting host used for forming the light-emitting layer was the same except that the comparative compound and the exemplified compound according to the present invention were changed from Comparative 1 to Table 2, respectively. Organic EL elements 2-2 to 2-20 were produced.

<< Evaluation of organic EL elements >>
About the produced organic EL elements 2-1 to 2-20, in the same manner as in the method described in Example 1, evaluation of light emission efficiency (measurement of external extraction quantum efficiency), measurement of light emission lifetime, and voltage increase during driving Table 2 shows the results obtained. In addition, in each said evaluation, it represented with the relative value which set each characteristic value of the organic EL element 2-1 to 100.

  As is apparent from the results shown in Table 2, the organic EL device of the present invention in which each organic layer is formed by a wet coating method has a longer light emission lifetime and emits less voltage ΔV during driving than the comparative example. I can see that

Example 3
<Production of full-color display device>
(Production of blue light emitting element)
The organic EL element 1-11 produced in Example 1 was used as a blue light emitting element.

(Production of green light emitting element)
In the production of the organic EL element 1-1 described in Example 1, a green light emitting element was produced in the same manner except that D-1 was used instead of D-26 as the light emitting dopant.

(Production of red light emitting element)
In the production of the organic EL element 1-1 described in Example 1, a red light emitting element was produced in the same manner except that D-10 was used instead of D-26 as the light emitting dopant.

  The produced red light emitting element, green light emitting element, and blue light emitting element are juxtaposed on the same substrate to produce an active matrix type full color display device having the form as shown in FIGS.

  That is, a plurality of pixels 3 (light emission color is a red region pixel, a green region pixel, a blue region pixel, etc.) juxtaposed with a wiring portion including a plurality of scanning lines 5 and data lines 6 on the same substrate. The scanning lines 5 and the plurality of data lines 6 in the wiring portion are each made of a conductive material, and the scanning lines 5 and the data lines 6 are orthogonal to each other in a grid pattern and are connected to the pixels 3 at the orthogonal positions.

  The plurality of pixels 3 are driven by an active matrix system provided with an organic EL element corresponding to each emission color, a switching transistor as an active element, and a driving transistor, and a scanning signal is applied from the scanning line 5. The image data signal is received from the data line 6 and light is emitted according to the received image data. In this way, a full color display device was manufactured by appropriately juxtaposing red, green, and blue pixels.

  It was confirmed that when the obtained full color display device was driven, high brightness, high durability, and clear full color moving image display could be obtained.

Example 4
<< Preparation of white light emitting element and white lighting device >>
The electrode of the transparent electrode substrate described in Example 1 was patterned to 20 mm × 20 mm, and α-NPD was formed thereon with a thickness of 25 nm as a hole transport layer in the same manner as in Example 1, The heated boat containing the exemplified compound 16 as the luminescent host, the boat containing D-26, and the boat containing the D-10 were energized independently, and the exemplified compound 16 as the luminescent host and D- 26 and D-10 were adjusted to have a deposition rate of 100: 5: 0.6, and the deposition was performed to a thickness of 30 nm to provide a light emitting layer.

Next, 10 nm of BAlq was deposited to provide a hole blocking layer. Furthermore, it was deposited Alq ₃ at 40nm an electron transporting layer.

  Next, in the same manner as in Example 1, a square perforated mask having the same shape as the transparent electrode made of stainless steel was placed on the electron injection layer, lithium fluoride 0.5 nm as the cathode buffer layer and aluminum as the cathode. 150 nm was deposited and formed.

  The organic EL device thus produced was provided with a sealing can in the same manner as described in Example 1, and a flat lamp as shown in FIGS. 3 and 4 was produced. When this flat lamp was energized, almost white light was obtained, and it was found that it could be used as a lighting device.

Example 5
<< Preparation of white organic EL element >>
After patterning on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) on which a 100 nm × 100 mm, 1.1 mm-thick glass substrate of ITO (Indium Tin Oxide) was deposited to a thickness of 100 nm, this ITO transparent electrode was provided. The transparent substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and UV ozone cleaning was performed for 5 minutes.

  On this transparent 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 film formation by a spin coating method, the film was dried at 200 ° C. for 1 hour to provide a first hole transport layer having a thickness of 30 nm.

  The substrate was transferred to a nitrogen atmosphere, and a solution of 50 mg of commercially available ADS254BE (American Dye Source, Inc.) dissolved in 10 ml of toluene was spin-coated on the hole transport layer at 2500 rpm for 30 seconds to form a thin film. Formed. It vacuum-dried at 60 degreeC for 1 hour, and formed the 2nd positive hole transport layer.

  Next, a compound obtained by dissolving 100 mg of Exemplified Compound 16 as a luminescent host, 0.5 mg of D-10 and 16 mg of D-26 in 10 ml of butyl acetate was formed by spin coating at 1000 rpm for 30 seconds. Filmed. It vacuum-dried at 60 degreeC for 1 hour, and was set as the light emitting layer.

  Further, using a solution obtained by dissolving 25 mg of ET-10 in 5 ml of hexafluoroisopropanol (HFIP), a film was formed by spin coating under the condition of 2000 rpm for 30 seconds, and then vacuum dried at 60 ° C. for 1 hour. One electron transport layer was formed.

  Subsequently, this substrate was fixed to a substrate holder of a vacuum deposition apparatus, 200 mg of ET-7 was put in a molybdenum resistance heating boat, and attached to the vacuum deposition apparatus.

After depressurizing the vacuum tank to 4 × 10 ⁻⁴ Pa, the resistance heating boat containing ET-7 was energized and heated, and deposited on the formed electron transport layer at a deposition rate of 0.1 nm / second, A second electron transport layer having a thickness of 20 nm was formed. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Then, 0.5 nm of lithium fluoride and 110 nm of aluminum were vapor-deposited, the cathode was formed, and the organic EL element was produced.

  This organic EL element was provided with a sealing can having the same method and the same structure as in Example 1, and a flat lamp as shown in FIGS. 3 and 4 was produced. When this flat lamp was energized, almost white light was obtained, and it was found that it could be used as a lighting device.

DESCRIPTION OF SYMBOLS 1 Display 3 Pixel 5 Scan line 6 Data line 7 Emitted light A Display part B Control part 101 Organic EL element 102 Glass cover 105 Cathode 106 Organic EL layer 107 Glass substrate with a transparent electrode 108 Nitrogen gas 109 Water catching agent

Claims (6)

An organic electroluminescence device comprising a compound having a partial structure represented by the following general formula (2) or general formula (3) .

(Wherein R ₁ to R ₆ , R _{10 to} R ₁₄ , RA, RB, Rc, and Rd each independently represent a hydrogen atom or a substituent . At least one of RA and RB, or Rc, At least one of Rd is an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, a non-aromatic heterocyclic group, an aromatic heterocyclic group, a halogen atom, an alkoxyl group, or a cycloalkoxyl. Group, aryloxy group, alkylthio group, cycloalkylthio group, arylthio group, alkoxycarbonyl group, aryloxycarbonyl group, sulfamoyl group, ureido group, acyl group, acyloxy group, amide group, carbamoyl group, sulfinyl group, alkylsulfonyl group or Arylsulfonyl group, amino group, silyl group, trialkylboron Represents any group selected from a group, a triarylboron group, a nitro group, a cyano group, and a hydroxyl group, and both RA and RB represent the same substituent other than a hydrogen atom, and X represents O, S, or —NRa. Ra represents an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, a non-aromatic heterocyclic group or an aromatic heterocyclic group.

(In the formula, R _{1 to} R ₆ , R _{11 to} R ₁₆ , RA, RB and Rc each independently represent a hydrogen atom or a substituent, and at least one of RA, RB and Rc is an alkyl group. , Cycloalkyl group, alkenyl group, alkynyl group, aromatic hydrocarbon group, non-aromatic heterocyclic group, aromatic heterocyclic group, halogen atom, alkoxyl group, cycloalkoxyl group, aryloxy group, alkylthio group, cycloalkylthio group , Arylthio group, alkoxycarbonyl group, aryloxycarbonyl group, sulfamoyl group, ureido group, acyl group, acyloxy group, amide group, carbamoyl group, sulfinyl group, alkylsulfonyl group or arylsulfonyl group, amino group, silyl group, trialkyl Boron group, triaryl boron group, nitro group, cyano group, Represents any group selected from a droxyl group, and RA and RB both represent the same substituent other than a hydrogen atom, X represents O, S or —NRa, and Ra represents an alkyl group, a cycloalkyl group or an alkenyl group. Represents an alkynyl group, an aromatic hydrocarbon group, a non-aromatic heterocyclic group or an aromatic heterocyclic group.) The organic electroluminescent device according to claim 1, the light emitting format of the organic electroluminescent device is characterized in that it is a phosphorescent. The organic electroluminescent device according to claim 1 or 2, wherein the emission color is blue. The organic electroluminescent device according to claim 1 or 2, wherein the emission color is white. Display apparatus comprising the organic electroluminescent element of any one of claims 1 4. Lighting apparatus comprising the organic electroluminescent element of any one of claims 1 4.

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