JP2007053044A - Organic electroluminescent element, display device, and lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL element which shows an excellent emission luminance with a small voltage rise and a dark spot when driven at a constant current, and furthermore has a high stability with the passage of time at high temperature and high humidity, and to provide a display device and a lighting system using the same. <P>SOLUTION: The organic electroluminescent element has an electrode and at least one layer or more of organic layers on a substrate. At least one layer of the organic layers is a luminous layer containing a host compound and a dopant, the viscosity of a composition prepared to form the luminous layer is 0.5-20 mPa s, and the film surface density of at least one layer of the organic layers is 1.10-1.25 g/cm<SP>3</SP>. <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, and injects electrons and holes into the light emitting layer and recombines them to generate excitons. This is an element that emits light by using light emission (fluorescence / phosphorescence) when the exciton is deactivated, and can emit light at a voltage of several volts to several tens of volts, and is self-luminous. In addition, it is attracting attention from the viewpoints of space saving, portability and the like because it is a thin film type complete solid element with a wide viewing angle and high visibility.

  In recent years, Princeton University has reported an organic EL device using phosphorescence emission from an excited triplet (see Non-Patent Document 1), and research on materials that exhibit phosphorescence at room temperature has become active (for example, Non-Patent Document 1). 2 and Patent Document 1). When excited triplets are used, the upper limit of internal quantum efficiency is 100%, so in principle the luminous efficiency is four times that of excited singlets, and the performance is almost the same as that of cold cathode tubes. It can be applied to 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 (see, for example, Patent Document 2 and Patent Document 3). Although the external extraction efficiency of 20%, which is the theoretical limit, was achieved for green light emission, sufficient efficiency was not yet obtained for light emission of other colors, and improvement was necessary. In particular, a device that emits blue light with high efficiency is demanded, and a compound having a larger band gap is desired.

  On the other hand, organic light-emitting elements that achieve high-intensity light emission are elements in which organic substances are stacked by vacuum vapor deposition, but depending on the application method from the viewpoint of simplification of the manufacturing process, processability, large area, etc. Device fabrication is also disclosed (see, for example, Patent Document 4).

  In addition, as another problem, there is dielectric breakdown due to the phenomenon that the film is deposited during film formation and the film quality becomes extremely rough, and it is studied to adjust the viscosity of the composition before coating (for example, patents). Reference 5).

However, conventional organic EL devices are desired to be improved in terms of voltage rise when driven at a constant current, generation of dark spots, and stability over time at high temperatures and high humidity. In addition, further improvement in emission luminance is desired.
US Pat. No. 6,097,147 JP 2002-1000047 A JP 2002-117978 A JP 2002-299061 A JP 2004-31360 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)

  The present invention has been made in view of the above problems, and an object of the present invention is to exhibit good light emission luminance, little increase in voltage and dark spot when driven at a constant current, and further, aging under high temperature and high humidity. An organic EL element having high stability, and a display device and a lighting device using the same are provided.

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

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 host compound and a dopant, and is prepared for forming the light-emitting layer. An organic electroluminescence device, wherein the composition has a viscosity of 0.5 to 20 mPa · s, and a film surface density of at least one layer of the organic layer is 1.10 to 1.25 g / cm ³ .

  2. 2. The organic electroluminescence device according to 1 above, wherein the dopant is a phosphorescent compound.

  3. 3. The organic electroluminescence device as described in 1 or 2 above, wherein the composition has a viscosity of 1 to 3 mPa · s.

4). 4. The organic electroluminescence device according to any one of 1 to 3, wherein a film surface density of at least one layer of the organic layer is 1.20 to 1.25 g / cm ³ .

  5. 5. The organic electroluminescence device as described in 4 above, wherein the host compound has a molecular weight of 400 to 2,000.

6). 4. The organic electroluminescence device according to any one of 1 to 3, wherein a film density of at least one layer of the organic layer is 1.10 to 1.15 g / cm ³ .

  7). 7. The organic electroluminescence device as described in 6 above, wherein the host compound has a molecular weight of 5,000 to 1,000,000.

8). 8. The organic electroluminescence device according to any one of 1 to 7, wherein the organic layer contains an organic solvent in an amount of 10 ⁻² to 10 ³ ppm.

  9. 9. The organic electroluminescence device according to any one of 1 to 8, wherein the substrate has a gas barrier layer.

  10. 10. The organic electroluminescence device according to any one of 1 to 9, wherein the light emission is red.

  11. 10. The organic electroluminescence device according to any one of 1 to 9, wherein the light emission is green.

  12 10. The organic electroluminescence device according to any one of 1 to 9, wherein the light emission is blue.

  13. 10. The organic electroluminescence device according to any one of 1 to 9, wherein the light emission is white.

  14 14. A display device comprising the organic electroluminescence element according to any one of 1 to 13 above.

  15. 14. An illumination device comprising the organic electroluminescence element according to any one of 1 to 13 above.

  16. 16. A display device comprising the illumination device according to 15 and a liquid crystal element as display means.

  ADVANTAGE OF THE INVENTION According to this invention, the organic EL element which shows favorable light-emission brightness, there are few voltage rises, a dark spot when driving at constant current, and also high stability with time at high temperature and high humidity, and a display using the same A device and a lighting device can be provided.

The inventor has prepared 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 prepared to form the light-emitting layer. The composition has a viscosity of 0.5 to 20 mPa · s, and the film surface density of at least one layer of the organic layer is set to 1.10 to 1.25 g / cm ³ , thereby providing good emission luminance. In addition, the present inventors have found that an organic electroluminescence device having a high voltage and low dark spot when driven at a constant current and having high temporal stability under high temperature and high humidity can be obtained.

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

  The composition used in the present invention will be described.

(viscosity)
The viscosity of the composition of the present invention is synonymous with absolute viscosity, and can be measured at 25 ° C. using a commercially available viscometer (B-type viscometer (manufactured by Toki Sangyo)).

  The viscosity of the composition prepared for forming the light emitting layer of the present invention is 0.5 to 10 mPa · s, and preferably 1 to 3 mPa · s. Thereby, it has the further improvement effect of a dark spot.

  The concentration of the organic compound contained in the composition of the present invention is 0.05 to 5% by mass, and preferably 0.1 to 1% by mass.

  Although there is no restriction | limiting in particular as an organic solvent used for this invention, For example, alcohols (methanol, ethanol, etc.), carboxylic acid esters (ethyl acetate, propyl acetate, etc.), nitriles (acetonitrile, etc.), ethers (isopropyl ether) , THF, etc.), aromatic hydrocarbons (cyclohexylbenzene, toluene, xylene, etc.), alkyl halides (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.

(Film density)
A method for measuring the film density will be described.

  In the present invention, the film density can be determined by an X-ray reflectivity measurement method. It is obtained by measuring the reflectance at a very low angle, for example, in the range of 0.2 degrees to 2 degrees, and fitting the obtained reflectance curve to the reflectance formula of the multilayer film sample obtained from the Fresnel formula. . For the fitting method, see L.C. G. Parratt, Phis. Rev. , 95, 359 (1954).

  Specifically, the X-ray generation source targets copper and operates at 50 kV-300 mA. X-rays monochromatized with a multilayer mirror and a Ge (111) channel cut monochromator are used. The measurement was performed using the software ATX-Crystal Guide Ver. 6.5.3.4, halved, after alignment adjustment, 2θ / ω = 0 ° to 1 ° from 0.002 ° / step to 0.05 ° / min. Scan with. After measuring the reflectance curve under the above measurement conditions, GXRR Ver. It can be determined using 2.1.0.0 analysis software.

The film density of at least one layer of the organic layer according to the present invention is 1.10 to 1.25 g / cm ³ , and as a result, the voltage rises when driven at a constant current, dark spots, and stable over time at high temperature and high humidity. Improved.

(Organic solvent content)
Next, the measuring method of organic solvent content is demonstrated.

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

The organic layer according to the present invention preferably 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.

  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, and the coating method is spin coating, dip coating, roll coating, bar coating, flexographic printing, screen printing, offset printing, inkjet method, preferably Is an inkjet method.

(Host compound)
Next, the host compound used in the present invention will be described.

  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.

  The host compound used in the present invention preferably has a band gap of 2.5 to 3.8 eV. More preferably, it is 2.9-3.8 eV, More preferably, it is 3.45-3.65 eV, Thereby, light-emitting luminance is improved further.

  Examples of the host compound used in the present invention include carbazole derivatives, azacarbazole derivatives, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, phenanthroline derivatives. Oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, organometallic compounds, arylmethane derivatives, and the like.

  Among these, compounds represented by the following general formulas (1) to (5) are more preferable.

Wherein, R ₁ to R ₄ represents a substituent. n1 and n2 represent the integer of 0-3. A ₁ and A ₂ represent a compound represented by the following general formula (2).

In the formula, Z ₁ and Z ₂ represent an aromatic heterocyclic ring or an aromatic hydrocarbon ring which may have a substituent, and Z ₃ represents a divalent 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 the compound 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 ₂₁ and A ₂₂ represent the compound represented by the general formula (2). L represents a divalent linking group.

More preferable among the general formulas (1), (2), and (4) is when Z ₁ and Z _{2 in} the general formula (2) are aromatic hydrocarbons.

In the formula, A ₃₁ and A 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. R ₃₁ and R ₃₂ represent a compound represented by the general formula (2).

In the general formulas (1), (3), (4) and (5), examples of the substituent represented by R _{1 to} R ₄ , R ₁₁ , R _{21 to} R ₂₄ , R ₃₁ and R ₃₂ include An alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as 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 2 to 8 carbon atoms, Vinyl, allyl, 2-butenyl, 3-pentenyl, etc.), alkynyl groups (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, and particularly preferably 2 to 8 carbon atoms). Rugyl, 3-pentynyl, etc.), aryl groups (preferably having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenyl, p-methylphenyl, naphthyl, etc. ), An amino group (preferably having 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, such as amino, methylamino, dimethylamino, diethylamino, dibenzylamino, etc.) An alkoxy group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as methoxy, ethoxy, butoxy, etc.), an aryloxy group (preferably having a carbon number) 6 to 20, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenyloxy, 2-naphthyloxy Etc.), an acyl group (preferably having 1 to 20 carbon atoms, 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 they are C2-C20, More preferably, it is C2-C16, Most preferably, it is C2-C12, for example, a methoxycarbonyl, an ethoxycarbonyl, etc., an aryloxycarbonyl group (preferably C7-20) , More preferably 7 to 16 carbon atoms, particularly preferably 7 to 10 carbon atoms, such as phenyloxycarbonyl, etc.), acyloxy groups (preferably 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, especially Preferably it has 2 to 10 carbon atoms, for example, acetoxy, benzoyloxy, etc.), acylamino group (preferably It has 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and particularly preferably 2 to 10 carbon atoms. For example, acetylamino, benzoylamino, etc., an alkoxycarbonylamino group (preferably 2 to 20 carbon atoms, more Preferably it has 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonylamino, etc., aryloxycarbonylamino group (preferably 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, Particularly preferably, it has 7 to 12 carbon atoms, for example, phenyloxycarbonylamino and the like, a sulfonylamino group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms). Yes, for example, methanesulfonylamino, benzenesulfonylamino, etc., sulfamoyl group (preferably carbon number) -20, more preferably 0 to 16 carbon atoms, particularly preferably 0 to 12 carbon atoms. For example, sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, phenylsulfamoyl etc.), carbamoyl group (preferably carbon The number is 1 to 20, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms. For example, carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl, etc.), alkylthio group (preferably 1 to 20 carbon atoms) , More preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, for example, methylthio, ethylthio, etc.), an arylthio group (preferably 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, especially Preferably it has 6 to 12 carbon atoms, such as phenylthio, etc., sulfonyl group (preferably Alternatively, it has 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms. For example, mesyl, tosyl, etc.), a sulfinyl group (preferably 1 to 20 carbon atoms, more preferably C1-C16, Most preferably, it is C1-C12, for example, methanesulfinyl, benzenesulfinyl, etc.), a ureido group (preferably C1-C20, more preferably C1-C16, especially preferably C1-C12, for example, ureido, methylureido, phenylureido, etc.), phosphoric acid amide group (preferably C1-C20, more preferably C1-C16, particularly preferably C1-C12 For example, diethyl phosphate amide, phenyl phosphate amide, etc.), 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, heterocyclic group (as a hetero atom, for example, nitrogen atom, oxygen atom) , A sulfur atom, a selenium atom, etc., preferably 1-30 carbon atoms, more preferably 1-20 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.

In the general formulas (2) and (4), the divalent linking group represented by L and L ₁ includes a hetero atom in addition to hydrocarbon groups such as alkylene, alkenylene, alkynylene, and arylene. Or a divalent linking group derived from a compound having an aromatic heterocycle such as a thiophene-2,5-diyl group or a pyrazine-2,3-diyl group (also referred to as a heteroaromatic compound). It may be a chalcogen atom such as oxygen or sulfur. Further, it may be a group such as an alkylimino group, a dialkylsilanediyl group, or a diarylgermandiyl group that connects and connects heteroatoms.

  As the host compound used in the present invention, either a low molecular compound or a high molecular compound can be used.

In the low molecular weight compound, the film surface density of at least one of the organic layers is 1.20 to 1.25 g / cm ³ , and the molecular weight is more preferably 400 to 2000, thereby further driving at a constant current. It has the effect of improving the aging stability under high voltage and high temperature and high humidity.

  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) to (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 a solution before the device is manufactured or during the device preparation. Further, a bond may be formed after the element is manufactured. When the polymerization reaction occurs, external energy (heat, light, ultrasonic waves, etc.) may be supplied, or the polymerization initiator, acid catalyst or 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 the current supplied at the time of driving the light emitting element or the generated light or heat. Two or more polymerizable compounds may be polymerized to form a copolymer.

  The molecular weight of the polymerized polymer compound is preferably 5,000 to 1,000,000 (weight average molecular weight), more preferably 5,000 to 200,000.

Further, it is more preferable that the film surface density is 1.10 to 1.15 g / cm ³ and the molecular weight is 5000 to 1000000, thereby further increasing the voltage when driven by a constant current, dark spots, and high temperature, It has the effect of improving the stability over time under high humidity.

  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, tert-butyl ester Peroxide initiators such as loperoxide, 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, etc. 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.

  Examples of the acid catalyst 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.

Basic catalysts 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, Na ₂ O and K Alkali metal oxides such as 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 sodium, potassium and rubidium And alkoxides such as cesium.

  Specific examples of the host compound preferably used in the present invention are listed below, but the present invention is not limited thereto.

(Dopant)
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 phosphorescence 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). Among them, the most preferable is an iridium compound.

  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 that, when a fluorescent compound is contained, produces fluorescence emission with a maximum emission wavelength different from the case where it is not contained, and preferably has a high fluorescence quantum yield in a solution state. It is. 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, pyrylium dyes, Examples include 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.

  Although the specific example of the fluorescent compound in connection with this invention is shown below, this invention is not limited to these.

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

  The organic EL 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 dopant.

  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, It refers to a layer containing a compound that emits light.

  The organic layer according to the present invention may have a hole transport layer, an electron transport layer, an anode buffer layer, a cathode buffer layer, and the like in addition to the light emitting layer as necessary, and has a structure sandwiched between a cathode and an anode. . Specific examples include the structures shown below.

(I) Anode / hole transport layer / light emitting layer / cathode (ii) Anode / light emitting layer / electron transport layer / cathode (iii) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (iv) Anode / Anode buffer layer / hole transport layer / light emitting layer / electron transport layer / cathode buffer layer / cathode Of the plural layers sandwiched between electrodes (anode and cathode) constituting the organic EL element, two organic layers are provided. It is preferable that it is above, and more preferably it is three or more layers.

<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.

  Further, a plurality of the above-mentioned host compounds and known 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. In addition, by using a plurality of phosphorescent compounds, it is possible to mix different light emission, thereby obtaining an arbitrary emission color. 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.

  As these known host compounds, compounds having a hole transporting ability and an electron transporting ability, preventing the emission of longer wavelengths, and having a high Tg (glass transition temperature) are preferable. The host compound has one of hole injection or transport and electron barrier properties. For example, a carbazole derivative, azacarbazole derivative, triazole derivative, oxadiazole derivative, imidazole derivative, polyarylalkane derivative, pyrazoline Derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, phenanthroline derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, organometallic compounds, arylmethane derivatives and the like.

  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 to the range of 5 nm-5 micrometers.

<< Hole injection layer, hole transport layer, electron injection layer, electron transport layer >>
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.

  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, an element having excellent light emitting performance such as accumulation at the interface in the light emitting layer and improvement in light emission efficiency is obtained.

《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 the 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 an organic EL element, and 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 further 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-4-3 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 08688 are linked in a starburst type ( MTDATA) 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.

(Hole injection layer thickness, hole transport layer thickness)
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 the 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.

  Examples of materials used for this 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, carbodiimides, Examples include fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives, and organometallic complexes. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which an oxygen atom of the oxadiazole ring is substituted with a sulfur atom, or a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  Or 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), etc., and the central metals of these metal complexes are In, Mg, Cu , Ca, Sn, Ga, or Pb can also be used as an electron transport material.

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

(Film thickness of electron transport layer)
Although the film thickness of an electron carrying layer does not have a restriction | limiting in particular, It is preferable to adjust to the range of 5 nm-5 micrometers. This electron transport layer may have a single layer structure composed of one or two or more of these electron transport materials, or may have a laminated structure composed of a plurality of layers having the same composition or different compositions.

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

  Furthermore, in addition to the basic constituent layers, layers having other functions may be laminated as necessary. For example, JP-A-11-204258 and 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)”.

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

"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, and 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 when pattern accuracy is not so high (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, 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 (Al2O3) 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.

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

  As a base material that can be used in the organic EL device of the present invention, there is no particular limitation on the type of glass, plastic and the like, 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 a mercapto compound having an acrylate compound and 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 what laminated | stacked 1 or 2 or more types of these resin by means, such as a lamination and a coating, as a base film.

  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. Further, 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 simultaneous biaxial stretching, etc. 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.

  In addition, in the base material according to the present invention, surface treatment such as corona treatment, flame treatment, plasma treatment, glow discharge treatment, roughening treatment, chemical treatment and the like may be performed before forming the deposited film.

Further, an anchor coating agent layer may be formed on the surface of the substrate according to the present invention for the purpose of improving the adhesion with the 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.

《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 element of the present invention may have a diffraction grating in any layer or in a 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 one of the layers or in the medium (in the transparent substrate or the transparent electrode), but is preferably in the vicinity of the organic light emitting layer where light is generated. At this time, the period of the diffraction grating is preferably 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.

《Gas barrier layer》
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.

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.

  The gas barrier layer according to the present invention is formed by spraying a raw material, which will be described later, a spray method, a spin coating method, a sputtering method, an ion assist method, a plasma CVD method, which will be described later, a plasma CVD method, which will be described later, at atmospheric pressure or near atmospheric pressure Can be formed by applying.

  FIG. 1 is an example showing the 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 is formed by laminating layers having different densities on a base material 22, and a structure in which an adhesion film 23, a ceramic film 24, a protective film 25, and a ceramic film 24 are laminated as one unit. Shows an example in which two units 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 which will be described later, an atmospheric pressure which will be described later or a pressure near atmospheric pressure is used. It can be formed by applying a plasma CVD method or the like.

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

Example 1
As a base material, on a polyethylene naphthalate film having a thickness of 100 μm (a film made by Teijin-Dyupon Co., Ltd., hereinafter abbreviated as “PEN”), the following atmospheric pressure plasma discharge treatment apparatus and discharge conditions are used to form a barrier with the profile configuration shown in FIG. A substrate 1 having a layer was 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.

  The roll electrode serving as the first electrode is coated with a high-density, high-adhesion alumina sprayed film by an atmospheric plasma method on a jacket roll metallic base material made of titanium alloy T64 having cooling means by cooling water, and roll diameter It was set to 1000 mmφ. On the other hand, the square electrode of the second electrode is a hollow rectangular tube-shaped titanium alloy T64 covered with 1 mm of the same dielectric material with the same thickness under the same conditions, and the opposing rectangular tube-shaped fixed electrode group and did.

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, an appropriate filter was 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 in 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 with 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 g / cm ³ 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 with a vaporizer manufactured by Lintec Corporation) 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 g / cm ³ as a result of measurement by the X-ray reflectivity method using MXP21 manufactured by Mac Science.

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.

(Preparation of organic EL element 1-1)
Next, as shown in FIG. 3, using a commercially available inkjet head 10 (KM512S non-aqueous head manufactured by Konica Minolta), a polymer of the following exemplary compound A15 as a host, phosphorescent compound Ir-1 (mass ratio 100) : 5) and the fluid D1 containing THF was discharged onto the ITO substrate 100 to form a light-emitting layer 111 having a thickness of 50 nm under the conditions of 100 ° C. for 60 minutes.

  Next, using the inkjet head 10, a fluid D2 containing a polymer of the following exemplary compound A28 and THF is discharged onto the light emitting layer 111, and the film thickness is 50 nm under the conditions of 100 ° C. and 60 minutes. An electron transport layer 112 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, the organic solvent content of the light emitting layer 111 and the electron transport layer 112 was adjusted to the values shown in Table 1. Furthermore, the base material 1 which has a gas barrier layer was affixed on it, and the organic EL element 1-1 was produced.

<Synthesis of Polymer of Exemplary Compound A15>
The reaction vessel was charged with 1.34 g (2.5 mmol) of Exemplified Compound A15, 0.010 g (0.061 mmol) of 2,2′-azobis (isobutyronitrile) (AIBN) and 30 ml of butyl acetate, and the atmosphere was replaced with nitrogen. Then, it was made to react at 80 degreeC 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 poured into methanol and reprecipitated twice for further purification. After recovery, vacuum drying is performed to obtain 1.20 g of the target Exemplified Compound A4 polymer as a powder. It was. The copolymer had a weight average molecular weight of 10,000 in terms of polystyrene (according to GPC measurement using HFIP (hexafluoroisopropanol) as an eluent).

A polymer of exemplary compound A28 was synthesized in the same manner. (Weight average molecular weight 26000)
(Preparation of organic EL elements 1-2 to 1-8)
In the production of the organic EL element 1-1, organic EL elements 1-2 to 1-8 were produced in the same manner except that the materials of the respective layers were changed to the materials shown in Table 1 below.

(Preparation of organic EL element 1-9)
After depositing A31 and phosphorescent compound Ir-1 (mass ratio 100: 5) as a light emitting layer on a glass substrate having an indium tin oxide transparent electrode (ITO electrode) at a thickness of 50 nm according to a conventional method, an electron transport layer is formed. As follows, M1 was vapor-deposited with a film thickness of 50 nm, and then Al was vapor-deposited with a film thickness of 200 nm to form a cathode. Furthermore, the base material 1 which has a gas barrier layer was bonded together, and the organic EL element 1-9 was produced.

(Preparation of organic EL element 1-10)
In the production of the organic EL element 1-1, the organic EL element was similarly prepared except that the material of each layer was changed to the material shown in Table 1 below and the glass substrate having an indium tin oxide transparent electrode (ITO electrode). 1-10 was produced.

  The film density and viscosity of the light emitting layer of the produced organic EL devices 1-1 to 1-10 and the organic solvent content of the organic layer were measured by the methods described above. The results are shown in Table 1.

(Evaluation of organic EL elements)
The obtained organic EL device was evaluated as follows, and the results are shown in Table 2.

<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 is expressed as a relative value when the organic EL element 1-8 is 100. The light emission luminance was measured using CS-1000 (manufactured by Konica Minolta Sensing).

<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 one month at 60 ° C. and 70% 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.

<Dark spot>
Further, after driving for 30 hours at a constant current of 15 mA / cm ² , the number of non-luminous spots (dark spots) that can be visually confirmed in the range of 2 mm × 2 mm square was measured.

  As is clear from Table 2, in the organic EL device of 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. In addition, the improvement effect was more remarkable when a substrate having a gas barrier layer was used as compared with a glass substrate.

Example 2
(Preparation of organic EL element 2-1)
Similarly to Example 1, a commercially available inkjet head 10 was used to discharge a fluid containing Exemplified Compound A36 and THF onto the ITO substrate 100, and a hole with a thickness of 50 nm under conditions of 100 ° C. for 60 minutes. A transport layer was formed.

  Next, a fluid containing Exemplified Compound A31, phosphorescent compound Ir-12 (mass ratio 100: 4) and THF as a host was discharged onto the hole transport layer, and the film thickness was measured at 100 ° C. for 60 minutes. A 50 nm light emitting layer was formed.

  Next, a fluid containing exemplary compound A35 and THF was discharged to the light emitting layer, and an electron transport layer having a thickness of 50 nm was formed at 100 ° C. for 60 minutes. Next, aluminum 113 (cathode) having a thickness of 200 nm was deposited on the electron transport layer.

  Further, the organic solvent content in the organic layer was adjusted as shown in Table 3. Furthermore, the base material 1 which has a gas barrier layer was affixed on it, and the organic EL element 2-1 was formed. In addition, as shown in Table 3, the viscosity of the composition of the light emitting layer was adjusted.

(Preparation of organic EL elements 2-1 to 2-6)
In the production of the organic EL element 2-1, the materials of each layer were changed to the materials shown in Table 3 below, and the remaining volatile solvent content of the organic layer was adjusted as shown in Table 3 except that the drying conditions were adjusted. Thus, organic EL elements 2-1 to 2-6 were produced.

(Preparation of organic EL elements 2-1 to 2-6)
Further, in the production of the organic EL element 1-10 of Example 1, the material of each layer was changed to the material shown in Table 3 below, and the residual volatile solvent content of the organic layer was adjusted as shown in Table 3 Made organic EL elements 2-7 and 2-8 in the same manner.

(Evaluation of organic EL elements)
About the produced organic EL element, it evaluated by the same measuring method and evaluation method as Example 1. FIG. The results are shown in Table 4. The light emission luminance was expressed as a relative value when the organic EL element 2-7 was 100.

  As is clear from the results in Table 4, the organic EL device of the present invention is excellent in light emission luminance, has little voltage increase when driven at a constant current, has few dark spots, and has high stability over time at high temperature and high humidity. It turns out that. In particular, when combined with a phosphorescent compound, the improvement effect was remarkable.

Example 3
The organic EL device 2-4 of the present invention produced in Example 2 and the organic EL device 2-4 of the present invention produced in Example 2 were produced in the same manner except that the phosphorescent compound was replaced with Ir-1. A green light-emitting organic EL element and a red light-emitting organic EL element produced in the same manner except that the phosphorescent compound of the organic EL element 2-4 of the present invention was replaced with Ir-9 were juxtaposed on the same substrate. The active matrix type full-color display device shown in FIG. FIG. 5 shows only a schematic diagram of the display section A of the produced full-color display device. That is, a wiring portion including a plurality of scanning lines 5 and data lines 6 and a plurality of juxtaposed pixels 3 (light emission color is a red region pixel, a green region pixel, a blue region pixel, etc.) on the same substrate. Each of the scanning lines 5 and the plurality of data lines 6 in the wiring portion is 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 (details). Is 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. Then, an 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 4
<Production of lighting device>
The non-light-emitting surface of each of the blue, green, and red light-emitting organic EL elements produced in Example 3 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. 6 is a schematic view of the lighting device, and FIG. 7 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 5
(Preparation of organic EL element 5-1)
An organic EL element 5-1 having a material and a film thickness configuration shown in Table 5 below was manufactured under the same conditions as those for manufacturing the organic EL element 1-1 of Example 1. % In Table 5 represents a mass ratio (%).

The compositions of the light emitting layers 1 to 3 were all adjusted to have a viscosity of 1.0 mPa · s, and the film density was 1.22 g / cm ³ . The drying conditions were adjusted so that the solvent content of the organic layer was 10 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 the organic EL element 1-1.

  The obtained organic EL element 5-1 was made into the illuminating 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 5-1 and the color filter has a wide color reproduction range and excellent performance in color reproducibility.

It is a schematic diagram which shows an example of the layer structure of the transparent gas barrier film which concerns on this invention, and its density profile. 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 the organic EL element 1-1. It is a figure which shows an active matrix system full color display apparatus. It is a schematic diagram of the display part A of a 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 1 Display 3 Pixel 5 Scan line 6 Data line 10 Inkjet head 21 Gas barrier layer 22 Base material 23 Adhesion film 24 Ceramic film 25 Protection film 30 Plasma discharge treatment chamber 35 Roll electrode 36 Electrode 41, 42 Power supply 51 Gas supply device 55 Electrode cooling Unit 100 ITO substrate 101 Organic EL element 102 Glass cover 105 Cathode 106 Organic EL layer 107 Glass substrate with transparent electrode 108 Nitrogen gas 108
109 Water catching agent 109
111 Hole Transport Layer 112 Electron Transport Layer 113 Cathode 114 Gas Barrier Film A Display Unit B Control Unit D Droplet

Claims (16)

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 host compound and a dopant, and is prepared for forming the light-emitting layer. An organic electroluminescence device, wherein the composition has a viscosity of 0.5 to 20 mPa · s, and a film surface density of at least one layer of the organic layer is 1.10 to 1.25 g / cm ³ . The organic electroluminescence device according to claim 1, wherein the dopant is a phosphorescent compound. The organic electroluminescence device according to claim 1, wherein the composition has a viscosity of 1 to 3 mPa · s. The organic electroluminescent element according to any one of claims 1 to ³ , wherein a film surface density of at least one layer of the organic layer is 1.20 to 1.25 g / cm ³ . The organic electroluminescence device according to claim 4, wherein the host compound has a molecular weight of 400 to 2,000. The organic electroluminescence device according to any one of claims 1 to ³ , wherein a film density of at least one layer of the organic layer is 1.10 to 1.15 g / cm ³ . The organic electroluminescent device according to claim 6, wherein the host compound has a molecular weight of 5,000 to 1,000,000. The organic electroluminescent element according to claim 1, wherein the organic layer contains an organic solvent in an amount of 10 ⁻² to 10 ³ ppm. The organic electroluminescent element according to claim 1, wherein the substrate has a gas barrier layer. Light emission is red, The organic electroluminescent element of any one of Claims 1-9 characterized by the above-mentioned. Light emission is green, The organic electroluminescent element of any one of Claims 1-9 characterized by the above-mentioned. The organic electroluminescence element according to claim 1, wherein the light emission is blue. Light emission is white, The organic electroluminescent element of any one of Claims 1-9 characterized by the above-mentioned. A display device comprising the organic electroluminescence element according to claim 1. An illuminating device comprising the organic electroluminescence element according to claim 1. A display device comprising the lighting device according to claim 15 and a liquid crystal element as a display means.

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