JP2007042726A - Organic electroluminescent element, display device, and illumination device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL element exhibiting excellent emission luminance, having less dark spot and having high aging stability at high temperature and high humidity, and to provide a display device and an illumination device employing the same. <P>SOLUTION: In the electroluminescent element having an electrode and at least one or more organic layers on a substrate, at least one layer of the organic layers is a light-emitting layer containing dopant and has an electron transport layer adjacent to the light-emitting layer, the electron transport layer contains an organic compound having the HOMO of -5.0 to -6.9 eV and LUMO of -1.0 to -2.0 eV, and the organic layer contains an organic solvent of 10<SP>-2</SP>to 10<SP>3</SP>ppm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  Conventionally, there is an electroluminescence display (ELD) as a light-emitting electronic display device. Examples of the constituent elements of ELD include inorganic electroluminescent elements and organic electroluminescent elements (hereinafter also referred to as organic EL elements).

  An organic EL device has a structure in which a light emitting layer containing a compound that emits light is sandwiched between a cathode and an anode, injects electrons and holes into the light emitting layer, and recombines them to generate excitons (exciton). It is an element that emits light by using light emission (fluorescence / phosphorescence) when this exciton is deactivated, and can emit light at a voltage of several volts to several tens of volts, and is further self-luminous. It is attracting attention from the viewpoints of space saving, portability, etc. because of its wide viewing angle, high visibility, and thin film type solid state element.

  In recent years, Princeton University has reported an organic EL device using phosphorescence emission from an excited triplet (see, for example, Non-Patent Document 1), and research on materials that exhibit phosphorescence at room temperature has become active (for example, (See Non-Patent Document 2 and Patent Document 1.) When the excited triplet is used, the upper limit of the internal quantum efficiency is 100%. In principle, the luminous efficiency is four times that of the excited singlet, and the performance is almost the same as that of a cold cathode tube. Is applicable and attracts attention. For example, many compounds have been studied for synthesis centering on heavy metal complexes such as iridium complexes (see, for example, Non-Patent Document 3).

  Currently, further improvement in light emission efficiency and long life of organic EL elements using phosphorescence is being studied. In order to obtain high luminous efficiency, optimization of the light emitting layer (for example, refer to Patent Document 2) and introduction of a hole blocking layer (for example, refer to Patent Document 3) have been studied. For green light emission, the external extraction efficiency of 20%, which is the theoretical limit, has been achieved, but for other colors of light emission, sufficient efficiency has not yet been obtained and improvement has been required. In particular, there is a demand for an element that emits blue light with high efficiency.

On the other hand, organic light-emitting elements that achieve high-intensity light emission are elements in which organic substances are stacked by vacuum deposition. From the viewpoints of simplifying the manufacturing process, processability, and increasing the area, etc. The device fabrication according to is also disclosed (for example, see Patent Document 4). However, conventional organic electroluminescence devices are desired to be improved in terms of voltage rise when driven at a low voltage, generation of dark spots, and stability over time at high temperatures and high humidity. In addition, further improvement in light emission luminance is desired.
US Pat. No. 6,097,147 JP 2002-1000047 A JP 2002-117978 A JP 2002-299061 A M.M. A. Baldo et al. , Nature, 395, 151-154 (1998) M.M. A. Baldo et al. , Nature, 403, 17, 750-753 (2000) S. Lamansky et al. , J .; Am. Chem. Soc. 123, 4304 (2001)

  An object of the present invention is to provide an organic EL element that exhibits good light emission luminance, has a small voltage increase when driven at a constant current, has little dark spots, and has high temporal stability under high temperature and high humidity, and a display using the same It is providing a device and a lighting device.

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

(Claim 1)
In an organic electroluminescence device having an electrode and at least one organic layer on a substrate, at least one of the organic layers is a light-emitting layer containing a dopant, and has an electron transport layer adjacent to the light-emitting layer, The electron transport layer contains an organic compound having a HOMO of −5.0 to −6.9 eV and a LUMO of −1.0 to −2.0 eV, and the organic layer contains an organic solvent of 10 ⁻² to 10 ³ ppm. An organic electroluminescence device containing the organic electroluminescence device.

(Claim 2)
The organic electroluminescence device according to claim 1, wherein the dopant is a phosphorescent compound.

(Claim 3)
The organic electroluminescent device according to claim 1 or 2, wherein the organic compound has a HOMO of -5.4 to -6.8 eV and a LUMO of -1.2 to -1.9 eV.

(Claim 4)
The organic electroluminescent element according to claim 1, wherein the organic layer contains an organic solvent in an amount of 0.1 to 100 ppm.

(Claim 5)
The organic electroluminescence device according to any one of claims 1 to 4, wherein the organic compound has a weight average molecular weight of 5000 or more.

(Claim 6)
The organic electroluminescent element according to claim 1, wherein the substrate has a gas barrier layer.

(Claim 7)
The organic electroluminescence element according to claim 1, wherein the light emission is red.

(Claim 8)
The organic electroluminescence element according to claim 1, wherein the light emission is green.

(Claim 9)
The organic electroluminescence element according to claim 1, wherein the light emission is blue.

(Claim 10)
The organic electroluminescence element according to claim 1, wherein the light emission is white.

(Claim 11)
A display device comprising the organic electroluminescence element according to claim 7.

(Claim 12)
It has an organic electroluminescent element of any one of Claims 7-10, The illuminating device characterized by the above-mentioned.

(Claim 13)
13. A display device comprising the illumination device according to claim 12 and a liquid crystal element as a display means.

  According to the present invention, an organic EL element which exhibits good light emission luminance, has a low voltage increase when driven at a constant current, has few dark spots, and has high temporal stability under high temperature and high humidity, and a display device using the same, A lighting device could be provided.

The inventor of the present invention provides an organic electroluminescence device having an electrode and at least one organic layer on a substrate, wherein at least one of the organic layers is a light-emitting layer containing a dopant, and is adjacent to the light-emitting layer. The electron transport layer contains an organic compound having a HOMO of −5.0 to −6.9 eV and a LUMO of −1.0 to −2.0 eV, and further contains an organic solvent in the organic layer of 10 ^−2. By containing -10 ³ ppm, an organic electroluminescence device that exhibits good light emission luminance, has a high voltage when driven at a constant current, has few dark spots, and has high temporal stability under high temperature and high humidity. I found that I can do it.

  Hereinafter, each component of the present invention will be described in detail.

  In the present invention, the values of HOMO and LUMO are Gaussian 98 (Gaussian 98, Revision A.11.4, MJ Frisch, et al, Gaussian, Inc., Pittsburgh PA, software for molecular orbital calculation manufactured by Gaussian, USA. 2002.) and is defined as a value (eV unit converted value) calculated by performing structural optimization using B3LYP / 6-31G * as a keyword. This calculation value is effective because the correlation between the calculation value obtained by this method and the experimental value is high.

  Next, a method for measuring the organic solvent content used in the present invention will be described.

  The organic solvent contained in the organic layer according to the present invention can be measured by gas chromatography (GC) mass spectrometry (MS) equipped with a purge and trap sampler (PT-GC / MS). Specifically, a 10 cm × 10 cm square organic EL device was prepared, and the residual solvent was adsorbed in a gas recovery chamber and an organic gas adsorption tube (TENAX GR), and PT-GC / MS measurement was performed. The solvent concentration was determined from a calibration curve prepared using a reference sample with a known concentration.

The organic layer according to the present invention contains 10 ⁻² to 10 ³ ppm of an organic solvent. Preferably, the organic solvent is contained in an amount of 0.1 to 100 ppm, and this has the effect of further improving the voltage rise when driven at a constant current, dark spots, and stability over time at high temperature and high humidity.

  Although there is no restriction | limiting in particular as an organic solvent which concerns on this invention, For example, alcohol (methanol, ethanol, etc.), carboxylic acid esters (ethyl acetate, propyl acetate, etc.), nitriles (acetonitrile, etc.), ethers (isopropyl ether, THF), aromatic hydrocarbons (cyclohexylbenzene, toluene, xylene, etc.), halogenated alkyls (methylene chloride, etc.), saturated hydrocarbons (heptane, etc.). Of these, preferred are carboxylic acid esters, nitriles, ethers, aromatic hydrocarbons, alkyl halides, saturated hydrocarbons, and more preferred are carboxylic acid esters, ethers, aromatic hydrocarbons. It is kind.

  The boiling point of the organic solvent used in the present invention is preferably 200 ° C. or lower, more preferably 150 ° C. or lower.

  The organic layer according to the present invention is formed by a vapor deposition method or a coating method. In the coating method, spin coating, dip coating, roll coating, bar coating, flexographic printing, screen printing, offset printing, and inkjet method are preferable. Is an inkjet method.

  Next, the organic compound used in the present invention will be described.

  In the present invention, the organic compound contained in the electron transport layer adjacent to the light emitting layer will be described.

  As an organic compound used in the present invention, HOMO is −5.0 to −6.9 eV, and LUMO is −1.0 to −2.0 eV. Preferably, HOMO is -5.4 to -6.8 eV, LUMO is -1.2 to -1.9 eV, and more preferably, HOMO is -5.5 to -6.7 eV, and LUMO is -1.3 to -1.8 eV, which has a further effect of improving the light emission luminance.

  Examples of the organic compound used in the present invention include carbazole derivatives, azacarbazole derivatives, triazole derivatives, oxadiazole derivatives, imidazole derivatives, pyrazoline derivatives and pyrazolone derivatives, phenanthroline derivatives, oxazole derivatives, fluorenone derivatives, hydrazone derivatives, and organic metals. Examples thereof include compounds, arylmethane derivatives, and boron compounds.

  Among these, preferred are azacarbazole derivatives, triazole derivatives, oxadiazole derivatives, imidazole derivatives, organometallic compounds, and boron compounds, and more preferred are compounds represented by the following structures.

In formula, R < ₁ >, R < ₂ > represents a hydrogen atom and a substituent. R ₃ and R ₄ represent a substituent. n1 and n2 represent the integer of 0-3. A ₁ and A ₂ represent an arylamino group or a structure represented by the following general formula (2).

In the formula, Z ₁ represents an aromatic heterocyclic ring which may have a substituent, Z ₂ represents an aromatic heterocyclic ring or an aromatic hydrocarbon ring which may have a substituent, and Z ₃ represents a divalent group. Represents a linking group or a simple bond. L ₁ represents a divalent linking group or a simple bond.

In the formula, R ₁₁ represents a substituent. n11 represents an integer of 0 to 4. A ₁₁ and A ₁₂ represent an arylamino group or a structure represented by the general formula (2).

In the formula, R ₂₁ and R ₂₂ represent a substituent. n21 and n22 represent an integer of 0 to 3. A ₁ and A ₂ represent an arylamino group or a structure represented by the general formula (2). L represents a divalent linking group.

In the formula, R ₃₁ and R ₃₂ represent a substituent. n31 and n32 represent an integer of 0 to 3. Y represents an oxygen atom, a sulfur atom, an imino group, a sulfoxide group or a sulfonyl group. A ₃₁ and A ₃₂ represent an arylamino group or a structure represented by the general formula (2).

R _{1 to} R ₄ in the general formula (1), R _{11 in} the general formula (3), R ₂₁ and R ₂₂ in the general formula (4), and R ₃₁ and R ₃₂ in the general formula (5) are represented. Examples of the substituent include an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 8 carbon atoms. For example, methyl, ethyl, iso-propyl, tert- Butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.), an alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably C2-8, for example, vinyl, allyl, 2-butenyl, 3-pentenyl, etc.), alkynyl groups (preferably having 2-20 carbons, and more). Preferably, it has 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, such as propargyl, 3-pentynyl, etc.), an aryl group (preferably 6 to 30 carbon atoms, more preferably carbon atoms). 6 to 20, particularly preferably 6 to 12 carbon atoms, for example, phenyl, p-methylphenyl, naphthyl, etc.), amino group (preferably 0 to 20 carbon atoms, for example amino, methyl Amino, dimethylamino, diethylamino, dibenzylamino, diphenylamino, phenylnaphthylamino, etc.), an alkoxy group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 carbon atom). -8, for example, methoxy, ethoxy, butoxy, etc.), aryloxy group (preferably carbon 6 to 20, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenyloxy, 2-naphthyloxy, etc.), acyl groups (preferably 1 to 1 carbon atoms). 20, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as acetyl, benzoyl, formyl, pivaloyl, etc.), an alkoxycarbonyl group (preferably having 2 to 20 carbon atoms, More preferably, it has 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, and examples thereof include methoxycarbonyl, ethoxycarbonyl and the like, and an aryloxycarbonyl group (preferably 7 to 20 carbon atoms, more preferably It has 7 to 16 carbon atoms, particularly preferably 7 to 10 carbon atoms, and examples thereof include phenyloxycarbonyl. The ), An acyloxy group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, such as acetoxy and benzoyloxy), an acylamino group (preferably Has 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, and examples thereof include acetylamino, benzoylamino, and the like, and an alkoxycarbonylamino group (preferably having a carbon number). 2 to 20, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, and examples include methoxycarbonylamino and the like, aryloxycarbonylamino group (preferably 7 to 20 carbon atoms, More preferably, it has 7 to 16 carbon atoms, particularly preferably 7 to 12 carbon atoms. A sulfonylamino group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms, such as methanesulfonylamino and benzenesulfonylamino). ), A sulfamoyl group (preferably having 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, and particularly preferably 0 to 12 carbon atoms. For example, sulfamoyl, methylsulfamoyl, dimethylsulfamoyl , Phenylsulfamoyl, etc.), a carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as carbamoyl, methylcarbamoyl, And diethylcarbamoyl and phenylcarbamoyl). Kirthio group (preferably having 1 to 20 carbon atoms, more preferably having 1 to 16 carbon atoms, particularly preferably having 1 to 12 carbon atoms, such as methylthio, ethylthio, etc.), arylthio group (preferably having carbon number) 6 to 20, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, including, for example, phenylthio and the like, a sulfonyl group (preferably 1 to 20 carbon atoms, more preferably carbon number). 1 to 16, particularly preferably 1 to 12 carbon atoms, for example, mesyl, tosyl, etc.), sulfinyl group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably C1-C12, for example, methanesulfinyl, benzenesulfinyl, etc.), ureido group (preferably C1-C1) 20, More preferably, it is C1-C16, Most preferably, it is C1-C12, for example, ureido, methylureido, phenylureido etc. are mentioned. ), Phosphoric acid amide groups (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms, and examples thereof include diethyl phosphoric acid amide and phenyl phosphoric acid amide. .), Hydroxyl group, mercapto group, halogen atom (eg, fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group Group, heterocyclic group (including hetero atoms such as nitrogen atom, oxygen atom, sulfur atom, selenium atom, etc., preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, for example, imidazolyl, pyridyl , Furyl, piperidyl, morpholino, etc.). These substituents may be further substituted. If possible, they may be linked to form a ring.

  Of these, preferred are an alkyl group and an aryl group.

  The divalent linking group may be a hydrocarbon group such as alkylene, alkenylene, alkynylene, and arylene, and may contain a heteroatom, and may be a thiophene-2,5-diyl group or pyrazine-2,3. -It may be a divalent linking group derived from a compound having an aromatic heterocyclic ring (also called a heteroaromatic compound) such as a diyl group, or may be a chalcogen atom such as oxygen or sulfur. Further, it may be a group such as an imino group, a dialkylsilanediyl group, or a diarylgermandiyl group that joins and connects heteroatoms.

  As the organic compound used in the present invention, both a low molecular compound and a high molecular compound can be used, and a high molecular compound is particularly preferable.

  The polymer compound is obtained by polymerizing a compound having at least one polymerizable group (polymerizable compound). Examples of the polymerizable group include a vinyl group, an epoxy group, an oxetane group, an isocyanate group, and a thioisocyanate group. Is mentioned. Among these, a vinyl group is preferable. The organic compounds represented by the general formulas (1), (3), (4) and (5) according to the present invention may have these polymerizable groups at any position in the molecule.

  The polymerization reaction of the polymerizable compound will be described. As the time when the polymerization is formed, a polymer that has been polymerized in advance may be used, or polymerization may be performed in the solution before the device is manufactured or during the device preparation. Further, a bond may be formed after the element is manufactured. When a polymerization reaction is caused, external energy (heat, light, ultrasonic waves, etc.) may be supplied, or a polymerization initiator, an acid catalyst or a base catalyst may be added to cause the reaction. Alternatively, when the polymerization reaction is caused when the compound according to the present invention is contained in the light emitting element, the reaction may be caused by a current supplied at the time of driving the light emitting element or generated light or heat. Two or more polymerizable compounds may be polymerized to form a copolymer.

  The polymerized polymer preferably has a weight average molecular weight of 5,000 to 1,000,000, more preferably 5,000 to 100,000. Thereby, it has the further improvement effect of light-emitting luminance and a dark spot.

  Examples of the radical polymerization initiator include 2,2′-azobisbutyronitrile, 2,2′-azobiscyclohexanecarbonitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2 ′. -Azobis (2-methylbutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 4,4 '-Azobis (4-cyanovaleric acid), dimethyl 2,2'-azobisisobutyrate, 2,2'-azobis (2-methylpropionamidoxime), 2,2'-azobis (2- (2-imidazoline-2- Yl) propane), azo initiators such as 2,2'-azobis (2,4,4-trimethylpentane), benzoyl peroxide, di-t-butyl peroxide, t-butyl Peroxide initiators such as droperoxide and cumene hydroperoxide, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethyl ketal, benzyl-β-methoxyethyl acetal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenylketone, 4- Aromatic carbonyl initiators such as phenoxydichloroacetophenone, 4-t-butyldichloroacetophenone, 4-t-butyltrichloroacetophenone, 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one Is mentioned. Further, disulfide initiators such as tetraethylthiilam disulfide, nitroxyl initiators such as 2,2,6,6-tetramethylpiperidine-1-oxyl, 4,4′-di-t-butyl-2,2′- Living radical polymerization initiators such as a bipyridine copper complex-methyl trichloroacetate complex can also be used.

  Acid catalysts include activated clays, clays such as acidic clays, mineral acids such as sulfuric acid and hydrochloric acid, organic acids such as p-toluenesulfonic acid and trifluoroacetic acid, aluminum chloride, ferric chloride, stannic chloride, Lewis acids such as titanium trichloride, titanium tetrachloride, boron trifluoride, hydrogen fluoride, boron tribromide, aluminum bromide, gallium chloride, gallium bromide, and solid acids such as zeolite, silica, alumina, silica Various types such as alumina, cation exchange resin, heteropolyacid (for example, phosphotungstic acid, phosphomolybdic acid, silicotungstic acid, silicomolybdic acid) can be used.

Examples of the basic catalyst used in the present invention include alkali metal carbonates such as Li ₂ CO ₃ , Na ₂ CO ₃ and K ₂ CO ₃ , alkaline earth metal carbonates such as BaCO ₃ and CaCO ₃ , Li ₂ O, Alkali metal oxides such as Na ₂ O and K ₂ O, alkaline earth metal oxides such as BaO and CaO, alkali metals such as Na and K, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, or Examples thereof include alkoxides such as sodium, potassium, rubidium and cesium.

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

  The present invention may be used in combination with the organic compounds described above, or may be used in combination with a conventionally known electron transport material.

  Next, the dopant used in the present invention will be described.

  The dopant used in the present invention is a fluorescent compound or a phosphorescent compound, and a phosphorescent compound is particularly preferable.

  The phosphorescent compound in the present invention is a compound in which light emission from an excited triplet is observed, and is a compound having a phosphorescence quantum yield of 0.001 or more at 25 ° C. The phosphorescent quantum yield is preferably 0.01 or more, more preferably 0.1 or more. The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of the Fourth Edition Experimental Chemistry Course 7. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence quantum yield used in the present invention is only required to achieve the above phosphorescence quantum yield in any solvent.

  The phosphorescent compound used in the present invention is preferably a complex compound containing a group VIII metal in the periodic table of elements, more preferably an iridium compound, an osmium compound, or a platinum compound (platinum complex compound). Of these, iridium compounds are most preferred.

  Specific examples of the phosphorescent compound used in the present invention are shown below, but are not limited thereto. These compounds are described, for example, in Inorg. Chem. 40, 1704-1711, and the like. In addition, the fluorescent compound and phosphorescent compound to be contained may or may not have a polymerizable group or a reactive group.

  The phosphorescent compound used in the present invention may be used in combination with other phosphorescent compounds or fluorescent compounds.

  The fluorescent compound used in the present invention is a compound capable of obtaining fluorescence emission with a maximum emission wavelength different from the case where the fluorescent compound is not contained, and preferable one is that having a high fluorescence quantum yield in a solution state. is there. Here, the fluorescence quantum yield is preferably 10% or more, particularly preferably 30% or more. Specific fluorescent compounds include, for example, coumarin dyes, anthracene dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, and pyrylium dyes. Examples thereof include dyes, perylene dyes, stilbene dyes, polythiophene dyes, and rare earth complex phosphors. The fluorescence quantum yield here can be measured by the method described in Spectroscopic II, page 362 (1992 edition, Maruzen) of 4th edition Experimental Chemistry Course 7.

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

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

  The organic electroluminescence device of the present invention has an electrode (cathode and anode) and at least one organic layer on a substrate, and at least one of the organic layers is a light emitting layer containing a phosphorescent compound.

  In a broad sense, the light emitting layer according to the present invention is a layer that emits light when a current is passed through an electrode composed of a cathode and an anode. Specifically, when a current is passed through an electrode composed of a cathode and an anode, A layer containing a compound that emits light.

  In the organic EL device of the present invention, at least one of the organic layers is a light emitting layer, and has an electron transport layer adjacent to the light emitting layer. If necessary, in addition to the light-emitting layer and the electron transport layer, a hole transport layer, an anode buffer layer, a cathode buffer layer, and the like may be included, and a structure sandwiched between the cathode and the anode is employed. Specific examples include the structures shown below.

(I) Anode / light emitting layer / electron transport layer / cathode (ii) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (iii) Anode / anode buffer layer / hole transport layer / light emitting layer / electron transport Layer / cathode buffer layer / cathode Among the plural layers sandwiched between the electrodes (anode and cathode) constituting the organic EL element, the organic layer is preferably 2 layers or more, more preferably 3 layers or more. .

<Light emitting layer>
The light emitting layer of the organic EL device of the present invention preferably contains a host compound and a phosphorescent compound (also referred to as a phosphorescent compound). Thereby, the luminous efficiency can be further increased.

  In the present invention, the host compound is defined as a compound having a phosphorescence quantum yield of phosphorescence emission of less than 0.01 at room temperature (25 ° C.) among compounds contained in the light emitting layer.

  Further, a plurality of host compounds may be used in combination. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the organic EL element can be made highly efficient. Further, by using a plurality of types of phosphorescent compounds, it is possible to mix different light emission, and thereby any light emission color can be obtained. White light emission is possible by adjusting the kind of phosphorescent compound and the amount of doping, and can also be applied to illumination and backlight.

  The host compound according to the present invention is preferably a compound that has a hole transporting ability and an electron transporting ability, prevents the emission of light from becoming longer, and has a high Tg (glass transition temperature). The host compound has one of hole injection or transport and electron barrier properties. For example, a carbazole derivative, an azacarbazole derivative, a triazole derivative, an oxadiazole derivative, an imidazole derivative, a polyarylalkane derivative, Examples include pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, phenanthroline derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, organometallic compounds, and arylmethane derivatives.

  Of these, carbazole derivatives and azacarbazole derivatives are preferably used.

  There is no restriction | limiting in particular about the film thickness of the light emitting layer formed in this way, Although it can select suitably according to a condition, It is preferable to adjust film thickness in the range of 5 nm-5 micrometers.

  Next, other layers constituting the organic EL element in combination with the light emitting layer, such as a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer, will be described.

<< Hole injection layer, hole transport layer, electron injection layer, electron transport layer >>
The hole injection layer and hole transport layer used in the present invention have a function of transmitting holes injected from the anode to the light emitting layer. The hole injection layer and hole transport layer are formed of an anode and a light emitting layer. By interposing them, many holes are injected into the light emitting layer with a lower electric field, and electrons injected into the light emitting layer from the cathode, electron injection layer, or electron transport layer are injected into the light emitting layer and holes. Due to an electron barrier existing at the interface of the layer or the hole transport layer, it is accumulated at the interface in the light emitting layer, and the light emitting efficiency is improved.

《Hole injection material, hole transport material》
The material of the hole injection layer and hole transport layer (hereinafter referred to as hole injection material and hole transport material) has the property of transmitting holes injected from the anode to the light emitting layer. If it is a thing, there will be no restriction | limiting in particular, In a photoconductive material, what is conventionally used as a charge injection transport material of a hole, and well-known used for the hole injection layer of a EL element, a hole transport layer Any one can be selected and used.

  The hole injection material and the hole transport material have either hole injection or transport or electron barrier properties, and may be either organic or inorganic. Examples of the hole injection material and hole transport material include triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, An oxazole derivative, a styryl anthracene derivative, a fluorenone derivative, a hydrazone derivative, a stilbene derivative, a silazane derivative, an aniline-based copolymer, or a conductive polymer oligomer, particularly a thiophene oligomer can be used.

  The above-mentioned materials can be used as the hole injection material and 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 the aromatic tertiary amine compound and styrylamine compound 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; Bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl; 1,1-bis (4-di-p- Tolylaminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N′-diphenyl-N, N -Di (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadri N; N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenyl Amino- (2-diphenylvinyl) benzene; 3-methoxy-4′-N, N-diphenylaminostilbenzene; N-phenylcarbazole, and two more described in US Pat. No. 5,061,569 Having a condensed aromatic ring of, for example, 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (α-NPD), JP-A-4-30 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 8688 are linked in a starburst type ( MTDATA) etc. Further, 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.

  Alternatively, 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. The hole injection layer and the hole transport layer are formed by thinning the hole injection material and the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, or an LB method. Can be formed.

  Although there is no restriction | limiting in particular about the film thickness of a positive hole injection layer and a positive hole transport layer, It is preferable to adjust to the range about 5 nm-5 micrometers. The hole injection layer and hole transport layer may have a single layer structure composed of one or more of the above materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions.

<< Electron transport layer, electron transport material >>
The electron transport layer according to the present invention is only required to have a function of transmitting electrons injected from the cathode to the light emitting layer, and as the material thereof, any one of conventionally known compounds can be selected and used. Can do.

  Further, in the present invention, a buffer layer (electrode interface layer) may exist between the anode and the light emitting layer or the hole injection layer and between the cathode and the light emitting layer or the electron injection layer.

  The buffer layer is a layer provided between the electrode and the organic layer in order to lower the driving voltage and improve the luminous efficiency. “The organic EL element and its forefront of industrialization (published by NTS Corporation on November 30, 1998) 2), Chapter 2, “Electrode Materials” (pages 123 to 166) in detail, and includes an anode buffer layer and a cathode buffer layer.

  The details of the anode buffer layer are described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069 and the like. Specific examples include a phthalocyanine buffer layer represented by copper phthalocyanine, Examples thereof include an oxide buffer layer typified 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 are described in JP-A-6-325871, JP-A-9-17574, and JP-A-10-74586, and specifically, metal buffers represented by strontium, aluminum and the like. Examples thereof include an alkali metal compound buffer layer typified by lithium fluoride, an alkaline earth metal compound buffer layer typified by magnesium fluoride, an oxide buffer layer typified by aluminum oxide and lithium oxide, and the like.

  The buffer layer is preferably a very thin film, and the film thickness is preferably in the range of 0.1 to 100 nm, although it depends on the material.

  Further, in addition to the above basic constituent layers, layers having other functions may be laminated as required. For example, JP-A-11-204258, JP-A-11-204359, and “Organic EL element and its It may have a functional layer such as a hole blocking layer described on page 237 of “Industrialization Front Line (November 30, 1998, issued by NTT)”.

"electrode"
Next, the electrode of the organic EL element will be described. The electrode of the organic EL element consists of a cathode and an 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, conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO.

  The anode may be formed by depositing a thin film of these electrode materials by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or the pattern accuracy is not required so much (about 100 μm or more) ) May form a pattern through a mask having a desired shape during vapor deposition or sputtering of the electrode material. When light emission is extracted from the anode, it is desirable that the transmittance is greater than 10%, or 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 1 μm, preferably 10 to 200 nm.

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

  The cathode can be produced by forming a thin film from these electrode materials by a method such as vapor deposition or sputtering. Alternatively, the sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 1 μm, preferably 50 to 200 nm. In addition, in order to transmit light emission, if either one of the anode or the cathode of the organic EL element is transparent or translucent, it is advantageous because the light emission efficiency is improved.

"substrate"
The organic EL element of the present invention is preferably formed on a substrate (hereinafter also referred to as a base material, a substrate, a support, a film, etc.).

  As a substrate that can be used in the organic EL device of the present invention, there is no particular limitation on the type of glass, plastic, etc., and there is no particular limitation as long as it is transparent, For example, glass, quartz, and a transparent film can be mentioned. A particularly preferable substrate is a transparent film that can give flexibility to the organic EL element.

  Specifically, homopolymers or copolymers such as ethylene, polypropylene and butene, polyolefin (PO) resins such as copolymers, amorphous polyolefin resins (APO) such as cyclic polyolefins, polyethylene terephthalate (PET), Polyester resins such as polyethylene 2,6-naphthalate (PEN), polyamide (PA) resins such as nylon 6, nylon 12, copolymer nylon, polyvinyl alcohol (PVA) resin, ethylene-vinyl alcohol copolymer (EVOH) Polyvinyl alcohol resins such as polyimide (PI) resin, polyetherimide (PEI) resin, polysulfone (PS) resin, polyethersulfone (PES) resin, polyetheretherketone (PEEK) resin, polycarbonate (PC) resin , Polyvini Butyrate (PVB) resin, polyarylate (PAR) resin, ethylene-tetrafluoroethylene copolymer (ETFE), ethylene trifluoride chloride (PFA), ethylene tetrafluoride-perfluoroalkyl vinyl ether copolymer (FEP) Fluorine-based resins such as vinylidene fluoride (PVDF), vinyl fluoride (PVF), and perfluoroethylene-perfluoropropylene-perfluorovinyl ether-copolymer (EPA) can be used.

  In addition to the resins listed above, a resin composition comprising an acrylate compound having a radical-reactive unsaturated compound, a resin composition comprising an acrylate compound and a mercapto compound having a thiol group, epoxy acrylate, urethane acrylate, It is also possible to use a photocurable resin such as a resin composition in which an oligomer such as polyester acrylate or polyether acrylate is dissolved in a polyfunctional acrylate monomer, and a mixture thereof. Furthermore, it is also possible to use as a substrate film a laminate of one or more of these resins by means such as laminating or coating.

  These materials can be used alone or in combination as appropriate. Above all, ZEONEX and ZEONOR (manufactured by ZEON CORPORATION), amorphous cyclopolyolefin resin film ARTON (manufactured by JSR Corporation), polycarbonate film Pure Ace (manufactured by Teijin Limited), Konicatac of cellulose triacetate film Commercially available products such as KC4UX and KC8UX (manufactured by Konica Minolta Opto Co., Ltd.) can be preferably used.

  In addition, the base material according to the present invention using the above-described resins or the like may be an unstretched film or a stretched film.

  The base material according to the present invention can be produced by a conventionally known general method. For example, an unstretched substrate that is substantially amorphous and not oriented can be produced by melting a resin as a material with an extruder, extruding it with an annular die or a T-die, and quenching. In addition, the unstretched base material is subjected to a known method such as uniaxial stretching, tenter-type sequential biaxial stretching, tenter-type simultaneous biaxial stretching, tubular-type simultaneous biaxial stretching, or the flow direction of the base material (vertical axis), or A stretched substrate can be produced by stretching in the direction perpendicular to the flow direction of the substrate (horizontal axis). The draw ratio in this case can be appropriately selected according to the resin as the raw material of the base material, but is preferably 2 to 10 times in each of the vertical axis direction and the horizontal axis direction.

  Moreover, in the base material which concerns on this invention, you may perform surface treatments, such as a corona treatment, a flame treatment, a plasma treatment, a glow discharge process, a roughening process, a chemical treatment, before forming a vapor deposition film.

Furthermore, you may form an anchor coating agent layer in the base-material surface based on this invention for the purpose of the adhesive improvement with a vapor deposition film. Examples of the anchor coating agent used in this anchor coating agent layer include polyester resin, isocyanate resin, urethane resin, acrylic resin, ethylene vinyl alcohol resin, vinyl modified resin, epoxy resin, modified styrene resin, modified silicon resin, and alkyl titanate. Can be used alone or in combination. Conventionally known additives can be added to these anchor coating agents. The above-mentioned anchor coating agent is coated on the substrate by a known method such as roll coating, gravure coating, knife coating, dip coating, spray coating, etc., and anchor coating is performed by drying and removing the solvent, diluent, etc. Can do. The application amount of the anchor coating agent is preferably about 0.1 to 5 g / m ² (dry state).

  The substrate is conveniently a long product wound up in a roll. Since the thickness of the base material varies depending on the use of the film to be obtained, it cannot be specified unconditionally. However, when the film is used for packaging, it is not particularly limited, and is 3 to 400 μm from the suitability as a packaging material. It is preferable to be in the range of 6 to 30 μm.

  Moreover, as for the base material used for this invention, 10-200 micrometers is preferable as a film thickness of a film-shaped thing, More preferably, it is 50-100 micrometers.

<Display device>
The organic EL device of the present invention may be used as a kind of lamp such as an illumination or exposure light source, a projection device that projects an image, or a display device that directly recognizes a still image or a moving image. (Display) may be used. 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. Alternatively, it is possible to change the color of one emission color, for example, white emission to BGR using a color filter, and to achieve full color. Furthermore, it is possible to convert the emission color of the organic EL to another color by using a color conversion filter, and in this case, λmax of the organic EL emission is preferably 480 nm or less.

  An example of a display device composed of the organic EL element of the present invention will be described with reference to the drawings.

  FIG. 4 is a schematic diagram illustrating an example of a display device including organic EL elements. It is a schematic diagram of a display such as a mobile phone that displays image information by light emission of an organic EL element.

  The display 1 includes a display unit A having a plurality of pixels, a control unit B that performs image scanning of the display unit A based on image information, and the like. The control unit B is electrically connected to the display unit A, and sends a scanning signal and an image data signal to each of the plurality of pixels based on image information from the outside. The pixels for each scanning line are converted into image data signals by the scanning signal. In response to this, light is sequentially emitted and image scanning is performed to display image information on the display unit A.

  FIG. 5 is a schematic diagram of the display unit A.

  The display unit A includes a wiring unit including a plurality of scanning lines 5 and data lines 6, a plurality of pixels 3 and the like on a substrate. The main members of the display unit A will be described below. FIG. 5 shows a case where the light emitted from the pixel 3 is extracted in the direction of the white arrow (downward). 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 orthogonal positions (details are shown in FIG. Not shown). 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 that emit light on the same substrate.

  Next, the light emission process of the pixel will be described. FIG. 6 is a schematic diagram of a pixel.

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

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

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

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

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

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

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

  FIG. 7 is a schematic diagram of a passive matrix display device. In FIG. 7, a plurality of scanning lines 5 and a plurality of image data lines 6 are provided in a lattice shape so as to face each other with the pixel 3 interposed therebetween.

  When the scanning signal of the scanning line 5 is applied by sequential scanning, the pixel 3 connected to the applied scanning line 5 emits light according to the image data signal. In the passive matrix system, the pixel 3 has no active element, and the manufacturing cost can be reduced.

《Light extraction technology》
In the organic EL device of the present invention, in order to improve the extraction efficiency of light emitted from the light emitting layer, a prism or lens-like process is applied to the surface of the substrate, or a prism sheet or a lens sheet is attached to the surface of the substrate. Also good.

  The organic EL device of the present invention may have a low refractive index layer between the electrode and the substrate. Examples of the low refractive index layer include aerogel, porous silica, magnesium fluoride, and a fluorine-based polymer.

  Since the refractive index of the 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. Furthermore, it is preferable that it is 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 organic EL device of the present invention may have a diffraction grating in any interlayer or medium (in a transparent substrate or a transparent electrode). It is desirable that the diffraction grating to be introduced 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 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.

  The substrate according to the present invention preferably has a gas barrier layer. Thereby, it has the further improvement effect of the aging stability in a dark spot and high temperature and high humidity.

《Gas barrier layer》
The composition of the gas barrier layer according to the present invention is not particularly limited as long as it is a layer that blocks permeation of oxygen and water vapor. The oxygen permeability is preferably 0.005 ml / m ² / day or less at 23 ° C. and 0% RH, and the water vapor permeability measured according to the JIS K7129 B method is preferably 0.1 g / m ² / day or less. Specifically, an inorganic oxide is preferable as the material constituting the gas barrier layer according to the present invention, and examples include silicon oxide, aluminum oxide, silicon oxynitride, aluminum oxynitride, magnesium oxide, zinc oxide, indium oxide, and tin oxide. be able to.

  The thickness of the gas barrier layer in the present invention is appropriately selected depending on the type and configuration of the material used, and is suitably selected, but is preferably in the range of 5 to 2000 nm. This is because when the thickness of the gas barrier layer is thinner than the above range, a uniform film cannot be obtained, and it is difficult to obtain a barrier property against gas. Further, when the thickness of the gas barrier layer is larger than the above range, it is difficult to maintain the flexibility of the gas barrier film, and the gas barrier film is cracked due to external factors such as bending and pulling after film formation. This is because it may occur.

  For the gas barrier layer according to the present invention, a raw material described later is applied by a spray method, a spin coat method, a sputtering method, an ion assist method, a plasma CVD method, a plasma CVD method under atmospheric pressure or a pressure near atmospheric pressure described later, and the like. Can be formed.

  FIG. 1 is a schematic view showing a configuration of a substrate having a gas barrier layer according to the present invention.

  The structure and density of the substrate having the gas barrier layer according to the present invention will be described.

  The gas barrier layer 21 according to the present invention has a structure in which layers having different densities are laminated on a base material 22 and an adhesion film 23, a ceramic film 24, and a protective film 25 are laminated. FIG. 1 shows an example in which three layers are stacked. The density distribution in each layer is uniform, and the density of the ceramic film is set higher than the densities of the adhesion film and the protective film positioned above and below the ceramic film. Although each layer is shown as one layer in FIG. 1, it may have a configuration of two or more layers as necessary.

  As a method for forming an adhesion film, a ceramic film and a protective film on a substrate, a spray method, a spin coating method, a sputtering method, an ion assist method, a plasma CVD method, or a plasma CVD under a pressure at or near atmospheric pressure. It can be formed by applying a law or the like.

  Hereinafter, although an example explains the present invention, the present invention is not limited to this.

Example 1
<Preparation of organic EL element OLED1-1>
As a base material, a base material 1 having a barrier layer with a profile configuration shown in FIG. 1 is formed on a polyethylene naphthalate film (film made by Teijin-Dyupon Co., Ltd.) having a thickness of 100 μm with the following atmospheric pressure plasma discharge treatment apparatus and discharge conditions Produced.

(Atmospheric pressure plasma discharge treatment equipment)
Using the atmospheric pressure plasma discharge treatment apparatus of FIG. 2, a set of a roll electrode covered with a dielectric and a plurality of rectangular tube electrodes was produced as follows.

  A roll electrode 35 serving as a first electrode is formed by coating a titanium alloy T64 jacket roll metal base material having cooling means with cooling water with a high-density, high-adhesion alumina sprayed film by an atmospheric plasma method. The diameter was set to 1000 mmφ. On the other hand, the square electrode 36 of the second electrode is formed by coating a hollow rectangular tube titanium alloy T64 with a dielectric similar to the above with a thickness of 1 mm under the same conditions, and opposing square tube type fixed electrode groups. It was.

Ten square tube electrodes were arranged around the roll rotating electrode with a counter electrode gap of 1 mm. The total discharge area of the rectangular tube type fixed electrode group was 150 cm (length in the width direction) × 4 cm (length in the transport direction) × 10 (number of electrodes) = 6000 cm ² . In all cases, appropriate filters were installed.

  During plasma discharge, the first electrode (roll rotating electrode) is kept at a temperature of 120 ° C. and the second electrode (square tube fixed electrode group) is adjusted to 80 ° C., and the roll rotating electrode is rotated by a drive to form a thin film. went. Among the 10 rectangular tube-shaped fixed electrodes, two from the upstream side are used for forming the following first layer (adhesion layer), and the following six are used for forming the following second layer (ceramic layer). The following two were used for film formation of the third layer (protective layer), each condition was set, and three layers were laminated in one pass.

(First layer: adhesion layer)
Plasma discharge was performed under the following conditions to form an adhesion layer having a thickness of about 50 nm.

<Gas conditions>
Discharge gas: Nitrogen gas 94.5% by volume
Thin-film forming gas: Hexamethyldisiloxane (vaporized by mixing with nitrogen gas with a vaporizer manufactured by Lintec) 0.5% by volume
Additive gas: Oxygen gas 5.0% by volume
<Power supply conditions: Only the power supply on the first electrode side was used>
1st electrode side Power supply type
Frequency 80kHz
Output density 10W / cm ²
The density of the formed first layer (adhesion layer) was 1.90 as a result of measurement by the X-ray reflectivity method using MXP21 manufactured by MacScience.

(Second layer: Ceramic layer)
Plasma discharge was performed under the following conditions to form a ceramic layer having a thickness of about 30 nm.

<Gas conditions>
Discharge gas: Nitrogen gas 94.9% by volume
Thin film forming gas: Hexamethyldisiloxane (vaporized by mixing with nitrogen gas using a vaporizer manufactured by Lintec) 0.1% by volume
Additive gas: Oxygen gas 5.0% by volume
<Power supply conditions>
1st electrode side Power supply type
Frequency 80kHz
Output density 10W / cm ²
Second electrode side Power supply type High frequency power supply manufactured by Pearl Industrial Co., Ltd.
Frequency 13.56MHz
Output density 10W / cm ²
The density of the formed second layer (ceramic layer) was 2.20 as a result of measurement by the X-ray reflectivity method using MXP21 manufactured by Mac Science.

(3rd layer: protective layer)
Plasma discharge was performed under the following conditions to form a protective layer having a thickness of about 200 nm.

<Gas conditions>
Discharge gas: Nitrogen gas 93.0% by volume
Thin-film forming gas: Hexamethyldisiloxane (vaporized by mixing with nitrogen gas using a vaporizer manufactured by Lintec) 2.0% by volume
Additive gas: Oxygen gas 5.0% by volume
<Power supply conditions: Only the power supply on the first electrode side was used>
1st electrode side Power supply type
Frequency 80kHz
Output density 10W / cm ²
The density of the formed third layer (protective layer) was 1.95 as a result of measurement by the X-ray reflectivity method using MXP21 manufactured by MacScience.

As a result of measuring the water vapor transmission rate by a method based on JIS-K-7129B, it was 10 ⁻³ g / m ² / day or less. As a result of measuring the oxygen transmission rate by a method based on JIS-K-7126B, it was 10 ⁻³ g / m ² / day or less.

Next, after patterning a substrate having a 120 nm ITO (Indium Tin Oxide) film formed on the base material 1 having a gas barrier layer, the substrate with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol and dried nitrogen gas. And UV ozone cleaning was performed for 5 minutes. The ITO substrate 100 was manufactured by fixing to a substrate holder of a commercially available vacuum deposition apparatus and reducing the pressure to 4 × 10 ⁻⁴ Pa.

  Next, using a commercially available inkjet head 10 (KM512S non-aqueous head manufactured by Konica Minolta), M1 as a host compound, phosphorescent compound Ir-1,2,2′-azobis (isobutyronitrile): AIBN (mass ratio) The fluid D1 containing 100: 5: 1) and THF was discharged onto the ITO substrate 100 and dried at 100 ° C. for 40 minutes to form a light emitting layer 111 having a thickness of 50 nm.

  Next, using the inkjet head 10, a fluid D2 containing Exemplified Compound A10, AIBN (mass ratio 100: 1) and THF is discharged onto the light emitting layer 111, and dried at 100 ° C. for 40 minutes to form a film. An electron transport layer 112 having a thickness of 50 nm was formed.

  Next, an aluminum layer 113 (cathode) having a thickness of 200 nm was formed on the electron transport layer 112 by vapor deposition.

  Further, drying was performed so that the organic solvent content of the light emitting layer 111 and the electron transporting layer 112 was 5.0 ppm. Furthermore, the base material 1 which has a gas barrier layer was affixed on it, and organic EL element OLED1-1 was formed.

  FIG. 3 shows the discharge and film forming steps of the organic EL element OLED1-1.

<Preparation of organic EL element OLED1-2, 1-3>
Illustrative compound A9, 1.4 g (2.5 mmol), AIBN 0.010 g (0.061 mmol), and 30 ml of butyl acetate were added to the reaction vessel, and the reaction was carried out at 80 ° C. for 10 hours. After the reaction, it was poured into acetone for reprecipitation, and the polymer was recovered by filtration. The recovered polymer chloroform solution is purified by adding it again into methanol and reprecipitating twice, and after recovery, vacuum drying is performed to obtain 1.2 g of the target Exemplified Compound A9 polymer as a powder. It was. The copolymer had a weight average molecular weight of 11000 in terms of polystyrene (according to GPC measurement using HFIP (hexafluoroisopropanol) as an eluent).

  A polymer of compound M2 was synthesized in the same manner (weight average molecular weight 16000).

  In the manufacturing method of the organic EL element OLED1-1, instead of the fluid D1, the fluid D3 containing the polymer of M2 described above, the phosphorescent compound Ir-1 (mass ratio 100: 5) and THF is used. Instead of D2, a fluid D4 containing the polymer of the exemplified compound A9 and THF described above was used, and the organic EL of the light emitting layer 111 and the electron transport layer 112 was further dried so that the organic solvent was 13 ppm. Organic EL element OLED1-2 was produced with the manufacturing method similar to the manufacturing method of element OLED1-1.

  Moreover, in the manufacturing method of organic EL element OLED1-2, except having dried so that the organic solvent of the light emitting layer 111 and the electron carrying layer 112 might be 0.7 mass%, Organic EL element OLED1-3 was produced with the same manufacturing method.

<Preparation of organic EL elements OLED1-4 to 1-8>
In the manufacturing method of organic EL element OLED1-3, the organic EL element except that the material of each layer was changed to the material shown in Table 1 below and the organic solvent residual content of the organic layer was further dried as shown in Table 1. Organic EL elements OLED1-4 to 1-8 were produced by the same production method as the production method of OLED1-3.

<Preparation of organic EL element OLED1-9>
In the manufacturing method of the organic EL element OLED1-2, the material of each layer was changed to the material shown in Table 1 below, and the organic EL element OLED1-2 was changed to a glass substrate having an indium tin oxide transparent electrode (ITO electrode). Organic EL element OLED1-9 was produced with the manufacturing method similar to this manufacturing method.

<Evaluation of organic EL element>
The organic EL device obtained as described below was evaluated, and the results are shown in Table 1.

(Luminance brightness)
The emission luminance (cd / m ² ) of the organic EL device at a temperature of 23 ° C. and a 10 V DC voltage was measured. The light emission luminance was expressed as a relative value when the organic electroluminescence element OLED1-3 was set to 100. The light emission luminance was measured using CS-1000 (manufactured by Konica Minolta Sensing).

(Dark spot)
Further, after driving for 30 hours at a constant current of 10 mA / cm ² , the number of non-luminous spots (dark spots) that can be visually confirmed in a range of 2 mm × 2 mm square was measured.

(Voltage increase rate)
When driven at a constant current of 10 mA / cm ² , the initial voltage and the voltage after 100 hours were measured. The relative value of the voltage after 100 hours with respect to the initial voltage was defined as the voltage increase rate.

(Stability over time)
After the organic EL device was stored for 1 month at 50 ° C. and 60% RH, the emission luminance (cd / m ² ) was measured in the same manner as in Example 1. The stability over time was expressed as a relative value with respect to the measured luminance value before storage.

  As is apparent from Table 2, in the organic EL device using the method according to the present invention, the dark spot and the voltage increase rate were greatly reduced, the temporal stability was improved, and the emission luminance was also improved.

Example 2
In the manufacturing method of the organic EL element OLED1-3 of Example 1, the material of each layer was changed to the material shown in Table 3 below, and the organic solvent residual content of the organic layer was further dried as shown in Table 3. Organic EL elements OLED2-1 to 2-4 were produced by the same production method as that for organic EL element OLED1-3.

  Furthermore, in the manufacturing method of organic EL element OLED1-1 of Example 1, the material of each layer was changed to the material shown in Table 3 below, and the organic solvent remaining content of the organic layer was further dried as shown in Table 3. Produced the organic EL elements OLED2-5 to 2-7 by the same manufacturing method as that of the organic EL element OLED1-1.

  The organic EL elements OLED2-1 to 2-7 were also evaluated by the same evaluation method as in Example 1. The light emission luminance is expressed as a relative value when the organic electroluminescence element OLED2-1 is 100. Table 4 shows the evaluation results of the organic EL element.

  As is apparent from the results in Table 4, the organic EL device of the present invention is excellent in light emission luminance, has little voltage increase and dark spot when driven at a constant current, and has high temporal stability under high temperature and high humidity. I found out that

Example 3
<Preparation of organic EL element OLED3-1, 3-2>
On a glass substrate having an indium tin oxide transparent electrode (ITO electrode), after depositing NPD as a hole transport layer with a film thickness of 50 nm according to a conventional method, CBP as a light emitting layer, phosphorescent compound Ir-12 (mass ratio) 100: 5) was deposited to a thickness of 50 nm, A17 was deposited as an electron transport layer to a thickness of 50 nm, and then Al was deposited to a thickness of 110 nm to form a cathode. This was sealed in a sample bottle containing THF vapor under a nitrogen atmosphere, the content was adjusted as shown in Table 5, the base material 1 having a gas barrier layer was bonded, and the organic EL elements OLEDs 3-1 and 3 -2 was produced.

<Preparation of organic EL element OLED3-3>
Using M1 as a hole transport material, film formation was performed on a glass substrate having an indium tin oxide transparent electrode (ITO electrode) under conditions of a crucible temperature of 210 ° C., an irradiation electron current of 5 mA, and an irradiation electron energy of 50 eV. A thin film was formed. The film growth rate was 6 nm per minute, the film thickness of the polymer formed was 50 nm, and the average molecular weight was about 11000.

  Next, a polymer thin film is formed using M2 and phosphorescent compound Ir-12 (mass ratio 100: 5) as the organic compound of the light emitting layer under conditions of a crucible temperature of 210 ° C., an irradiation electron current of 5 mA, and an irradiation electron energy of 50 eV. did. The formed polymer had a film thickness of 50 nm and an average molecular weight of about 11,000.

  Similarly, Example Compound A9 was used as an electron transport material, and a polymer thin film was formed under the conditions of a crucible temperature of 210 ° C., an irradiation electron current of 5 mA, and an irradiation electron energy of 50 eV. A polymer thin film was formed. The formed polymer had a thickness of 50 nm and an average molecular weight of about 10,000.

  Next, aluminum having a thickness of 110 nm was deposited. This was sealed in a sample bottle containing THF vapor under a nitrogen atmosphere, the content was adjusted as shown in Table 5, and the base material 1 having a gas barrier layer was bonded to produce an organic EL element OLED3-3. .

<Preparation of organic EL element OLED3-4>
In the manufacturing method of the organic EL element OLED1-3, the material of each layer was changed to the material shown in Table 5 below, and the organic solvent remaining content of the organic layer was further dried as shown in Table 5 to be an organic EL element. Organic EL element OLED3-4 was produced with the manufacturing method similar to the manufacturing method of OLED1-3.

  The performance of the organic EL elements OLED3-1 to 3-4 produced in this manner was evaluated in the same manner as in Example 1. The light emission luminance is expressed as a relative value when the organic electroluminescence element OLED3-1 is 100.

  As is apparent from the results in Table 6, the organic EL device of the present invention is excellent in light emission luminance, has little increase in voltage and dark spots when driven at a constant current, and has high stability over time at high temperature and high humidity. I found out that

Example 4
Fabricated in the same manner except that the phosphorescent compound of the organic EL device 2-3 of the present invention produced in Example 2 and the organic EL device OLED2-3 of the present invention produced in Example 2 was replaced with Ir-1. The green light-emitting organic EL element and the red light-emitting organic EL element produced in the same manner except that the phosphorescent compound of the organic EL element OLED2-3 of the present invention was replaced with Ir-9 were juxtaposed on the same substrate. An active matrix type full-color display device shown in FIG. 4 was produced. FIG. 5 shows only a schematic diagram of the display section A of the produced full-color display device. 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 lattice shape and are connected to the pixels 3 at the orthogonal positions (for details, see FIG. Not shown). 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 a 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, full-color display is possible by appropriately juxtaposing the red, green, and blue pixels.

  By driving the full-color display device, a clear full-color moving image display was obtained.

Example 5
<Production of lighting device>
A non-light emitting surface of each of the blue, green, and red light emitting organic EL elements produced in Example 4 was covered with a glass case to obtain a lighting device. The lighting device has high luminous efficiency and can be used as a thin lighting device that emits white light with a long emission life. FIG. 8 is a schematic view of the lighting device, and FIG. 9 is a cross-sectional view of the lighting device. The organic EL element 101 was covered with a glass cover 102. Reference numeral 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.

Example 6
<Preparation of organic EL element OLED6-1>
An organic EL element OLED6-1 having a material and a film thickness configuration shown in Table 7 below was manufactured under the same conditions as the conditions for manufacturing the organic EL element OLED1-3 of Example 1. % In Table 7 represents a mass ratio (%).

  The drying conditions were adjusted so that the organic solvent content of the organic layer was 15 ppm. Next, aluminum having a thickness of 200 nm was deposited thereon. In sealing, the base material 1 which has a gas barrier layer was affixed similarly to organic EL element OLED1-1.

  The obtained organic EL element OLED6-1 was used as an illumination device as shown in FIG. The lighting device has high luminous efficiency and can be used as a thin lighting device that emits white light with a long emission life.

  Subsequently, the color gamut when the color filter marketed for displays was combined was evaluated. It was confirmed that the combination of the organic EL element 6-1 and the color filter has a wide color gamut and excellent performance in color reproducibility.

It is a schematic diagram which shows the layer structure of the transparent gas barrier film which concerns on this invention. It is the schematic which shows an example of the atmospheric pressure plasma discharge processing apparatus of the system which processes a base material between counter electrodes useful for this invention. It is a figure which shows the discharge and film-forming process of organic EL element OLED1-1. It is the schematic diagram which showed an example of the display apparatus comprised from an organic EL element. It is a schematic diagram of a display part. It is a schematic diagram of a pixel. It is a schematic diagram of a passive matrix type full-color display device. It is the schematic of an illuminating device. It is sectional drawing of an illuminating device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 30 Plasma discharge process chamber 35 Roll electrode 36 Electrode 41, 42 Power supply 51 Gas supply apparatus 55 Electrode cooling unit 100 ITO board | substrate 111 Hole transport layer 112 Electron transport layer 113 Cathode 114 Gas barrier film 10 Inkjet head D Droplet 1 Display 3 Pixel DESCRIPTION OF SYMBOLS 5 Scan line 6 Data line 7 Power supply line 10 Organic EL element 11 Switching transistor 12 Drive transistor 13 Capacitor A Display part B Control part 107 Glass substrate with a transparent electrode 106 Organic EL layer 105 Cathode 102 Glass cover 108 Nitrogen gas 109 Water trapping agent

Claims (13)

In an organic electroluminescence device having an electrode and at least one organic layer on a substrate, at least one of the organic layers is a light-emitting layer containing a dopant, and has an electron transport layer adjacent to the light-emitting layer, The electron transport layer contains an organic compound having a HOMO of −5.0 to −6.9 eV and a LUMO of −1.0 to −2.0 eV, and the organic layer contains an organic solvent of 10 ⁻² to 10 ³ ppm. An organic electroluminescence device containing the organic electroluminescence device. The organic electroluminescence device according to claim 1, wherein the dopant is a phosphorescent compound. The organic electroluminescent device according to claim 1 or 2, wherein the organic compound has a HOMO of -5.4 to -6.8 eV and a LUMO of -1.2 to -1.9 eV. The organic electroluminescent element according to claim 1, wherein the organic layer contains an organic solvent in an amount of 0.1 to 100 ppm. The organic electroluminescence device according to any one of claims 1 to 4, wherein the organic compound has a weight average molecular weight of 5000 or more. The organic electroluminescent element according to claim 1, wherein the substrate has a gas barrier layer. The organic electroluminescence element according to claim 1, wherein the light emission is red. The organic electroluminescence element according to claim 1, wherein the light emission is green. The organic electroluminescence element according to claim 1, wherein the light emission is blue. The organic electroluminescence element according to claim 1, wherein the light emission is white. A display device comprising the organic electroluminescence element according to claim 7. It has an organic electroluminescent element of any one of Claims 7-10, The illuminating device characterized by the above-mentioned. 13. A display device comprising the illumination device according to claim 12 and a liquid crystal element as a display means.

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