JP2006351837A - Organic electroluminescence element, its manufacturing method, display and illuminator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL element exhibiting high external extraction quantum efficiency and long in luminescence lifetime, and to provide its manufacturing method, and an illuminator and a display employing the organic EL element. <P>SOLUTION: In the electroluminescence element having a cathode and an anode on a substrate and a plurality of organic layers between them, at least one organic layer is formed using a dispersion solution and one of the organic layer contains a compound composed of an isomer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

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

  However, for organic EL elements for practical use in the future, development of organic EL elements that emit light efficiently and with high luminance with lower power consumption is desired.

  In Japanese Patent No. 3093796, a small amount of a phosphor is doped into a stilbene derivative, a distyrylarylene derivative or a tristyrylarylene derivative to achieve improvement in light emission luminance and a longer device lifetime. Further, an element having an organic light-emitting layer in which an 8-hydroxyquinoline aluminum complex is used as a host compound and a small amount of phosphor is doped thereto (for example, JP-A 63-264692), and an 8-hydroxyquinoline aluminum complex is used as a host compound. For example, an element having an organic light emitting layer doped with a quinacridone dye (for example, JP-A-3-255190) is known.

  As described above, when light emission from an excited singlet is used, the generation ratio of singlet excitons and triplet excitons is 1: 3, so the generation probability of luminescent excited species is 25%, and the light extraction efficiency is high. Is about 20%, so the limit of the external extraction quantum efficiency (ηext) is 5%.

  However, since Princeton University reported on an organic EL device using phosphorescence emission from an excited triplet (MA Baldo et al., Nature, 395, 151-154 (1998)), Research on materials that exhibit phosphorescence has become active.

  For example, M.M. A. Baldo et al. , Nature, 403, 17, 750-753 (2000), US Pat. No. 6,097,147, and the like.

  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 there is a possibility that almost the same performance as a cold cathode tube can be obtained. For this reason, it is attracting attention as a lighting application.

  For example, S.M. Lamansky et al. , J .; Am. Chem. Soc. , 123, 4304 (2001), etc., many compounds are being studied for synthesis centering on heavy metal complexes such as iridium complexes.

  In addition, the aforementioned M.I. A. Baldo et al. , Nature, Vol. 403, No. 17, 750-753 (2000), studies have been made using tris (2-phenylpyridine) iridium as a dopant.

In addition, M.M. E. Thompson et al. In The 10th International Works on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu) used L ₂ Ir (acac), for example, (ppy) ₂ Ir (acac) as e-J. 0 g, Tetsuo Tsutsui, etc., again The 10th International Workshop on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu) in, as a dopant tris (2-(p-tolyl) pyridine) iridium (Ir (ptpy) _3), tris Investigations using (benzo [h] quinoline) iridium (Ir (bzq) ₃ ) and the like have been conducted (note that these metal complexes are generally called orthometalated iridium complexes).

  In addition, the S. Lamansky et al. , J .; Am. Chem. Soc. , 123, 4304 (2001), etc., attempts have been made to form devices using various iridium complexes.

  In order to obtain high luminous efficiency, in the 10th International Workshop on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu), Ikai et al. Uses a hole transporting compound as a host of a phosphorescent compound. In addition, M.M. E. Thompson et al. Use various electron transporting materials as a host of phosphorescent compounds, doped with a novel iridium complex.

  In any case, the light emission luminance and light emission efficiency of the light emitting device are greatly improved compared to conventional devices because the emitted light is derived from phosphorescence. In the past, it has been known to introduce an electron withdrawing group such as a fluorine atom, a trifluoromethyl group, and a cyano group into phenylpyridine as a substituent, and to introduce picolinic acid or a pyrazabole-based ligand as a ligand. (For example, see Non-Patent Documents 1 and 2.)

  In addition to the problem of shortening the wavelength, there is a problem that the concentration is quenched by aggregation / association of the dopant itself, and the efficiency is lowered. Therefore, a more highly efficient device that suppresses the concentration quenching is desired.

In addition, organic EL elements using these iridium complexes are currently produced mainly by vapor deposition. Research on producing an organic EL element by a coating method has been actively conducted, but the present situation is that it is difficult to produce an element by a coating method due to low solubility of an iridium complex. Therefore, it is desired to improve the solubility of the iridium complex.
Inorganic Chemistry, Vol. 41, No. 12, pp. 3055-3066 (2002) Applied Physics Letters, 79, 2082 (2001)

  An object of the present invention is to provide an organic EL element having a high external extraction quantum efficiency and a long emission lifetime, a manufacturing method thereof, and an illumination device and a display device using the organic EL element.

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

(Claim 1)
In an organic electroluminescent element having a cathode and an anode on a substrate and having a plurality of organic layers therebetween, at least one of the organic layers is a layer formed using a dispersion liquid, and any of the organic layers An organic electroluminescence device comprising a compound consisting of crab isomers.

(Claim 2)
2. The organic electroluminescence device according to claim 1, wherein the layer formed using the dispersion contains a compound composed of an isomer.

(Claim 3)
The organic electroluminescence device according to claim 2, wherein the dispersion is prepared from a dispersion of a compound comprising an isomer.

(Claim 4)
The organic luminescence device according to claim 1, wherein the isomer is a structural isomer.

(Claim 5)
The organic luminescence device according to any one of claims 1 to 3, wherein the isomer is a stereoisomer.

(Claim 6)
The organic electroluminescent device according to any one of claims 1 to 5, wherein the compound comprising the isomer is a phosphorescent complex, a host compound, or a hole transport material.

(Claim 7)
The organic electroluminescence device according to claim 1, wherein the abundance ratio of one isomer in the compound consisting of the isomers is 0.001 to 0.5.

(Claim 8)
The organic electroluminescent element according to claim 1, wherein one of the organic layers is a light emitting layer containing a phosphorescent complex.

(Claim 9)
The organic electroluminescent device according to claim 8, wherein the phosphorescent complex is a compound composed of an isomer.

(Claim 10)
10. The organic electroluminescence device according to claim 8, wherein the phosphorescent complex is an iridium complex.

(Claim 11)
Light emission is white, The organic electroluminescent element of any one of Claims 1-10 characterized by the above-mentioned.

(Claim 12)
When manufacturing the organic electroluminescent element of any one of Claims 1-11, it forms into a film by the apply | coating method using a dispersion liquid, The manufacturing method of the organic electroluminescent element characterized by the above-mentioned.

(Claim 13)
The method for producing an organic electroluminescent element according to claim 12, wherein the coating method is an inkjet method.

(Claim 14)
A display device using the organic electroluminescence element according to claim 11.

(Claim 15)
An organic electroluminescent element according to claim 11 is used.

  According to the present invention, it is possible to provide an organic EL element having a high external extraction quantum efficiency and a long light emission lifetime, a method for manufacturing the organic EL element, and an illumination device and a display device using the organic EL element.

  The present invention relates to an organic electroluminescence device having a cathode and an anode on a substrate and having a plurality of organic layers therebetween, wherein at least one of the organic layers is a layer formed using a dispersion, and the organic One of the layers is characterized by containing an isomer compound, and it is particularly preferable that the layer formed using the dispersion liquid contains an isomer compound, and the dispersion liquid comprises an isomer. It is preferably prepared from a dispersion of compounds. Here, the compound consisting of isomers is a mixture of isomers.

  The isomers, structural isomers, and stereoisomers are described in page 74 of the RIKEN Dictionary (5th edition).

  In solution coating, when the upper layer is applied on the already applied lower layer, the lower layer component is dissolved in the solvent used to dissolve the upper layer component (generally a highly soluble solvent is used), and the upper layer is dissolved. And the lower layer mix. However, when using a dispersion for upper layer coating, it is also possible to select a solvent with low solubility, and the lower layer component is less likely to dissolve in the solvent constituting the dispersion during upper layer coating. It is considered possible to suppress the mixing ratio. When the upper layer component and the lower layer component are mixed, there is a case where the device life is deteriorated, but it is expected that the deterioration can be improved by a dispersion coating method.

As a fine particle forming method, a well-known method for producing a fine particle dispersion can be used. For example, there are dispersion by physical force and emulsification dispersion by a homogenizer (high pressure, ultrasonic wave, etc.), a bead mill, a jet mill, and an optimizer. In addition to the above method, in the case of a polymer material, polymer fine particles are synthesized by a method such as gas phase polymerization, emulsion polymerization, suspension polymerization, etc., and this is dispersed (in some cases, redispersion may be necessary). ) And can be used in the dispersion method according to the present invention. Further, these methods may be used in combination. A reprecipitation method has also been reported as a method for preparing nanoparticles (Chemistry and Industry, page 137, 2002). By using this method, it is possible to produce nano-sized direct nanoparticles, which is suitable for obtaining the effects of the present invention. (Reference: P27223200 for nonlinear optical material manufacturing method)
The compound consisting of isomers is selected from a phosphorescent complex, a host compound or a hole transport material, and a phosphorescent complex is particularly preferred. The phosphorescent complex is preferably an iridium complex. In addition, the abundance ratio of one isomer in the compound consisting of isomers is 0.001 to 0.5.

  The constituent layers of the organic EL element of the present invention will be described. In this invention, although the preferable specific example of the layer structure of an organic EL element is shown below, this invention is not limited to these.

(I) Anode / light emitting layer / electron transport layer / cathode (ii) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (iii) Anode / hole transport layer / light emitting layer / hole blocking layer / electron Transport layer / cathode (iv) Anode / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode (v) Anode / anode buffer layer / hole transport layer / light emitting layer / hole Blocking layer / electron transport layer / cathode buffer layer / cathode Here, the light emitting layer may be a monochromatic light emitting layer having emission maximum wavelengths of 430 to 480 nm, 510 to 550 nm, and 600 to 640 nm, respectively. At least three light emitting layers may be laminated to form a white light emitting layer, and a non-light emitting intermediate layer may be provided between the light emitting layers. The organic EL device of the present invention is preferably a white light emitting layer.

  Each layer which comprises the organic EL element of this invention is demonstrated.

"anode"
As the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such electrode materials include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ and ZnO. Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used. For the anode, these electrode materials may be formed into a thin film by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or when pattern accuracy is not so high (about 100 μm or more) A pattern may be formed through a mask having a desired shape at the time of vapor deposition or sputtering of the electrode material. Or when using the substance which can be apply | coated like an organic electroconductivity compound, wet film forming methods, such as a printing system and a coating system, can also be used. When light emission is extracted from the anode, it is desirable that the transmittance be greater than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 to 1000 nm, preferably 10 to 200 nm.

"cathode"
On the other hand, as the cathode, a material having a work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Suitable are a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (Al ₂ O ₃ ) mixture, a lithium / aluminum mixture, aluminum and the like. The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm. In order to transmit the emitted light, if either one of the anode or the cathode of the organic EL element is transparent or translucent, the light emission luminance is improved, which is convenient.

  In addition, a transparent or semi-transparent cathode can be produced by producing the conductive transparent material mentioned in the description of the anode on the cathode after producing the metal with a thickness of 1 to 20 nm on the cathode. By applying the above, it is possible to manufacture a device in which both the anode and the cathode are transparent.

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

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

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

  The details of the anode buffer layer (hole injection layer) are described in JP-A Nos. 9-45479, 9-260062, and 8-288069. Representative examples thereof include copper phthalocyanine. Phthalocyanine buffer layers, oxide buffer layers typified by vanadium oxide, amorphous carbon buffer layers, polymer buffer layers using conductive polymers such as polyaniline (emeraldine) and polythiophene, and the like.

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

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

  The hole blocking layer has a function of an electron transport layer in a broad sense, and is composed of a hole blocking material that has a function of transporting electrons and has a remarkably small ability to transport holes, while transporting electrons, By blocking holes, the recombination probability of electrons and holes can be improved. Moreover, the structure of the electron carrying layer mentioned later can be used as a hole-blocking layer concerning this invention as needed.

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

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

  Further, in the present invention, when having a plurality of light emitting layers having different light emission colors, it is preferable that the light emitting layer whose light emission maximum wavelength is the shortest is the closest to the anode among all the light emitting layers. It is preferable to additionally provide a hole blocking layer between the shortest wave layer and the light emitting layer next to the anode next to the layer. Furthermore, it is preferable that 50% by mass or more of the compound contained in the hole blocking layer provided at the position has an ionization potential of 0.3 eV or more larger than the host compound of the shortest wave emitting layer.

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

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

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

  On the other hand, the electron blocking layer has a function of a hole transport layer in a broad sense, and is made of a material that has a function of transporting holes and has a remarkably small ability to transport electrons. The probability of recombination of electrons and holes can be improved by blocking. Moreover, the structure of the positive hole transport layer mentioned later can be used as an electron blocking layer as needed. The film thickness of the hole blocking layer and the electron transport layer according to the present invention is preferably 3 to 100 nm, and more preferably 5 to 30 nm.

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

  It is preferable that the light emitting layer of the organic EL device of the present invention contains a phosphorescent complex which is a compound composed of a host compound and an isomer according to the present invention. In the present invention, as the host compound, the following carbazole derivatives and azacarbazole derivatives are preferable.

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

  Further, a plurality of 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 efficiency of the organic EL element can be increased. Moreover, it becomes possible to mix different light emission by using multiple types of phosphorescence emission complexes, and, thereby, arbitrary luminescent colors can be obtained. White light emission is possible by adjusting the kind of phosphorescent complex and the amount of doping, and can also be applied to illumination and backlight.

  As a known host compound that may be used in combination, a compound that has a hole transporting ability and an electron transporting ability, prevents the emission of light from being increased in wavelength, and has a high Tg (glass transition temperature) is preferable.

  Specific examples of known host compounds include compounds described in the following documents.

  JP-A Nos. 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579, 2002-105445, 2002-343568, 2002 No. 141173, No. 2002-352957, No. 2002-203683, No. 2002-363227, No. 2002-231453, No. 2003-3165, No. 2002-234888, No. 2003-27048, No. 200 No. -255934, the 2002-260861 Patent, the 2002-280183 Patent, the 2002-299060 Patent, the 2002-302516 Patent, the 2002-305083 Patent, the 2002-305084 Patent, JP-like of Nos. 2002-308837.

  In the present invention, in the case of having a plurality of light emitting layers, it is preferable that 50% by mass or more of the host compound in each layer is the same compound because it is easy to obtain a uniform film property over the entire organic layer. More preferably, the phosphorescence emission energy of the compound is 2.9 eV or more because it is advantageous in efficiently suppressing energy transfer from the phosphorescence emission complex and obtaining high luminance. Phosphorescence emission energy means the peak energy of the 0-0 band of phosphorescence emission when the photoluminescence of a deposited film of 100 nm is measured on a substrate with a host compound.

  The host compound used in the present invention preferably has a phosphorescence emission energy of 2.9 eV or more and a Tg of 90 ° C. or more. If the Tg is lower than 90 ° C., the deterioration of the element over time (decrease in luminance, deterioration of film properties) is large and the market needs as a light source cannot be satisfied. That is, in order to satisfy both luminance and durability, it is preferable that phosphorescence emission energy is 2.9 eV or more and Tg is 90 ° C. or more. Tg is more preferably 100 ° C. or higher.

  In the present invention, in the case of having a plurality of light emitting layers, 50% by mass or more of the host compound of the light emitting layer is the same compound having a phosphorescence emission energy of 2.9 eV or more and a Tg of 90 ° C. or more. It is preferable. Surprisingly, even when the Tg is 90 ° C. or higher and each compound is excellent in durability, if a different compound is used for each light-emitting layer, the same compound is used for all the light-emitting layers. It has been found that there is a possibility of deterioration compared to the case. Although the cause of this is not clearly understood, when 50% by mass or more of the host compounds in all the light emitting layers are the same, that is, when the host compounds in all the light emitting layers are substantially the same, uniform film surface properties can be obtained. However, when a different compound is used for each light emitting layer, each compound may be stable, but non-uniformity is likely to occur at the layer interface or the like.

(Phosphorescent complex)
As a material used for the light emitting layer, it is preferable to contain a phosphorescent complex which is a compound composed of the isomer according to the present invention at the same time as containing the above host compound. As the phosphorescent complex, an iridium complex is particularly preferable.

  As structural isomers of iridium complexes, those described in “Basic Inorganic Chemistry” co-authored by Cotton, Wilkinson and Gauss, P156, etc. exist, but in particular in tris isomers represented by tris (2-phenylpyridine) iridium. There are facial and meridional bodies.

  Specific examples of the iridium complex preferably used in the organic EL device of the present invention are given below. However, the present invention is not limited to these.

All of these compounds have facial isomers and meridional isomers as structural isomers, each of which can be isolated by column chromatography, and its structure should be confirmed by ¹ H-NMR and ¹³ C-NMR. Can do.

  The phosphorescent complex according to the present invention is a compound in which light emission from an excited triplet is observed, is a compound that emits phosphorescence at room temperature (25 ° C.), and has a phosphorescence quantum yield of 0.2 at 25 ° C. 01 or more compounds. The phosphorescence quantum yield is 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 Experimental Chemistry Course 4 of the 4th edition. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence emission complex used for this invention should just achieve the said phosphorescence quantum yield in any solvent.

  There are two types of light emission of the phosphorescent complex, in principle. One is the recombination of the carrier on the host compound to which the carrier is transported, and the excited state of the host compound is generated. Energy transfer type to obtain light emission from the phosphorescent complex by transferring to the phosphorescent complex, and another is the carrier trap of the phosphorescent complex, carrier recombination occurs on the phosphorescent complex, Although it is a carrier trap type in which light emission from the phosphorescent complex can be obtained, in any case, the excited state energy of the phosphorescent complex is lower than the excited state energy of the host compound. is there.

  In addition to the iridium complex according to the present invention, a complex compound containing a group 8-10 metal in the periodic table of elements, preferably an osmium compound, a platinum compound (platinum complex compound), or a rare earth complex is used in combination. Also good. These compounds are described, for example, in Inorg. Chem. 40, 1704-1711, and the like.

  In the present invention, the phosphorescent maximum wavelength of the phosphorescent complex is not particularly limited, and can be obtained in principle by selecting a central metal, a ligand, a ligand substituent, and the like. The emitted light wavelength can be changed.

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

The white element referred to in the present invention means that when the front luminance at 2 ° C. viewing angle is measured by the above method, the chromaticity in the CIE 1931 color system at 1000 Cd / m ² is X = 0.33 ± 0.07, It is in the region of Y = 0.33 ± 0.07.

  The light emitting layer can be formed by forming the above compound by a known thinning method such as a vacuum deposition method, a spin coating method, a casting method, an LB method, or an ink jet method.

  In the present invention, the light emitting layer includes layers having different emission spectra in which the emission maximum wavelengths are in the range of 430 to 480 nm, 510 to 550 nm, and 600 to 640 nm, or a layer in which these are laminated.

  There is no restriction | limiting in particular as a lamination order of a light emitting layer, You may have a nonluminous intermediate | middle layer between each light emitting layer. In the present invention, it is preferable that at least one blue light emitting layer is provided at a position closest to the anode among all the light emitting layers.

  When four or more light emitting layers are provided, for example, blue / green / red / blue, blue / green / red / blue / green, blue / green / red / blue / green / red in order from the anode. In order to improve luminance stability, it is preferable to sequentially stack blue, green, and red.

  The total film thickness of the light emitting layer is not particularly limited, but is usually 2 nm to 5 μm, preferably 2 to 200 nm. In the present invention, it is preferably in the range of 10 to 20 nm. If it is too thin, it is difficult to obtain film uniformity. If it is thicker than this, a high voltage is required to obtain light emission, which is not preferable. A film thickness of 20 nm or less is preferable because it has the effect of improving the stability of the emission color with respect to the driving current as well as the voltage surface.

  The thickness of each light emitting layer is preferably selected in the range of 2 to 100 nm, and more preferably in the range of 2 to 20 nm. Although there is no restriction | limiting in particular about the film thickness relationship of each light emitting layer of blue, green, and red, It is preferable that the blue light emitting layer (the sum total when there are two or more layers) is the thickest among three light emitting layers.

  Moreover, in the range which maintains the said maximum wavelength, you may mix a several luminescent compound in each light emitting layer. For example, a blue light emitting compound having a maximum wavelength of 430 to 480 nm and a green light emitting compound having the same wavelength of 510 to 550 nm may be mixed in the blue light emitting layer.

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

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

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

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

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

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

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

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

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

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

  Conventionally, in the case of a single electron transport layer and a plurality of layers, an electron transport material (also serving as a hole blocking material) used for an electron transport layer adjacent to the light emitting layer on the cathode side is injected from the cathode. As long as it has a function of transferring electrons to the light-emitting layer, any material can be selected and used from among conventionally known compounds. For example, nitro-substituted fluorene derivatives, diphenylquinone derivatives Thiopyrandioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives and the like. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum Tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), and the like, and the central metals of these metal complexes are In, Mg, Metal complexes replaced with Cu, Ca, Sn, Ga or Pb can also be used as the electron transport material. In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transporting material. In addition, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and similarly to the hole injection layer and the hole transport layer, inorganic such as n-type-Si and n-type-SiC can be used. A semiconductor can also be used as an electron transport material.

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

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

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

《Support substrate》
The support substrate (hereinafter also referred to as a substrate, substrate, substrate, support, etc.) that can be used in the organic EL device of the present invention is not particularly limited in the type of glass, plastic, etc., and is transparent. May be opaque. When extracting light from the support substrate side, the support substrate is preferably transparent. Examples of the transparent support substrate preferably used include glass, quartz, and a transparent resin film. A particularly preferable support substrate is a resin film capable of giving flexibility to the organic EL element.

Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose acetate propionate (CAP), Cellulose esters such as cellulose acetate phthalate (TAC) and cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide , Polyethersulfone (PES), polyphenylene sulfide, polysulfones Cycloolefin resins such as polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic or polyarylate, Arton (trade name, manufactured by JSR) or Appel (trade name, manufactured by Mitsui Chemicals) Can be mentioned. The surface of the resin film may be formed with an inorganic film, an organic film or a hybrid film of both, and is preferably a barrier film having a water vapor permeability of 0.01 g / m ² · day · atm or less, Further, it is preferably a high barrier film having an oxygen permeability of 10 ⁻³ g / m ² / day or less and a water vapor permeability of 10 ⁻⁵ g / m ² / day or less.

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

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

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

  The external extraction quantum efficiency at room temperature of light emission of the organic EL device of the present invention is preferably 1% or more, more preferably 5% or more. Here, the external extraction quantum efficiency (%) = the number of photons emitted to the outside of the organic EL element / the number of electrons sent to the organic EL element × 100.

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

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

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

Specific examples include a glass plate, a polymer plate / film, and a metal plate / film. Examples of the glass plate include soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and polysulfone. Examples of the metal plate include those made of one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium, and tantalum. In the present invention, a polymer film and a metal film can be preferably used because the element can be thinned. Furthermore, the polymer film preferably has an oxygen permeability of 10 ⁻³ g / m ² / day or less and a water vapor permeability of 10 ⁻⁵ g / m ² / day or less.

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

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

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

  In addition, it is also preferable that the electrode and the organic layer are coated on the outside of the electrode facing the support substrate with the organic layer interposed therebetween, and an inorganic or organic layer is formed in contact with the support substrate to form a sealing film. . In this case, the material for forming the film may be any material that has a function of suppressing intrusion of elements that cause deterioration of the element such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like is used. it can. Further, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of organic materials. The method for forming these films is not particularly limited. For example, vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma A polymerization method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.

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

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

《Protective film, protective plate》
In order to increase the mechanical strength of the element, a protective film or a protective plate may be provided outside the sealing film or the sealing film on the side facing the support substrate with the organic layer interposed therebetween. In particular, when the sealing is performed by the sealing film, the mechanical strength is not necessarily high, and thus it is preferable to provide such a protective film and a protective plate. As a material that can be used for this, the same glass plate, polymer plate / film, metal plate / film, and the like used for the sealing can be used, but the polymer film is light and thin. Is preferably used.

《Light extraction》
The organic EL element emits light within a layer having a refractive index higher than that of air (refractive index is about 1.7 to 2.1), and can extract only about 15% to 20% of the light generated in the light emitting layer. It is generally said that there is no. This is because light incident on the interface (interface between the transparent substrate and air) at an angle θ greater than the critical angle causes total reflection and cannot be taken out of the device, or between the transparent electrode or light emitting layer and the transparent substrate. This is because light is totally reflected between the light and the light is guided through the transparent electrode or the light emitting layer, and as a result, the light escapes in the direction of the side surface of the device.

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

  In the present invention, these methods can be used in combination with the organic EL device of the present invention. However, a method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light emitter, or a substrate, transparent A method of forming a diffraction grating between any layers of the electrode layer and the light emitting layer (including between the substrate and the outside) can be suitably used. In the present invention, by combining these means, it is possible to obtain an element having higher luminance or durability.

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

  Examples of the low refractive index layer include aerogel, porous silica, magnesium fluoride, and a fluorine-based polymer. Since the refractive index of the transparent substrate is generally about 1.5 to 1.7, the low refractive index layer preferably has a refractive index of about 1.5 or less. 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 reduced when the thickness of the low-refractive index medium is about the wavelength of light and the electromagnetic wave exuded by evanescent enters the substrate.

  The method of introducing a diffraction grating into an interface or any medium that causes total reflection is characterized by a high effect of improving light extraction efficiency. This method uses the property that the diffraction grating can change the direction of light to a specific direction different from refraction by so-called Bragg diffraction such as first-order diffraction and second-order diffraction. Of these, light that cannot be emitted due to total reflection between layers, etc. is diffracted by introducing a diffraction grating into any layer or medium (inside a transparent substrate or transparent electrode). I want to take it out.

  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.

<Condenser sheet>
The organic EL element of the present invention can be processed on the light extraction side of the substrate, for example, by providing a microlens array-like structure or combined with a so-called condensing sheet, for example, in a specific direction, for example, the element light emitting surface On the other hand, the brightness | luminance in a specific direction can be raised by condensing in a front direction.

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

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

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

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

  First, a thin film made of a desired electrode material, for example, an anode material, is formed on a suitable substrate by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably 10 to 200 nm, thereby producing an anode. . Next, an organic compound thin film of a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and a hole blocking layer, which are organic EL element materials, is formed thereon.

  As a method for thinning the organic compound thin film, there are a vapor deposition method and a wet process (spin coating method, casting method, ink jet method, printing method) as described above, but it is easy to obtain a uniform film and a pinhole. In the present invention, film formation by a coating method such as a spin coating method, an ink jet method, or a printing method is particularly preferable.

  In the present invention, in the formation of the light emitting layer, it is preferable to form a film by a coating method using a solution in which a phosphorescent complex is dissolved or dispersed, and the coating method is particularly preferably an ink jet method.

  Examples of the liquid medium for dissolving or dispersing the phosphorescent complex composed of the isomer according to the present invention include ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, and halogenated hydrocarbons such as dichlorobenzene. , Organic solvents such as DMF and DMSO can be used. Moreover, as a dispersion method, it can disperse | distribute by dispersion methods, such as an ultrasonic wave, high shear force dispersion | distribution, and media dispersion | distribution.

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

  In addition, it is also possible to reverse the production order and produce the cathode, the electron injection layer, the electron transport layer, the light emitting layer, the hole transport layer, the hole injection layer, and the anode in this order. When a DC voltage is applied to the multicolor display device thus obtained, light emission can be observed by applying a voltage of about 2 to 40 V with the positive polarity of the anode and the negative polarity of the cathode. An alternating voltage may be applied. The alternating current waveform to be applied may be arbitrary.

<Application>
The organic EL element of the present invention can be used as a display device, a display, and various light emission sources. Examples of light sources include home lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, and light sources for optical sensors. However, the present invention is not limited to this, but it can be effectively used particularly as a backlight of a liquid crystal display device and a light source for illumination.

  In the organic EL device of the present invention, patterning may be performed by a metal mask, an ink jet printing method, or the like at the time of film formation, if necessary. When patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire element layer may be patterned.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this.

Example 1
(Preparation of solution coating solution)
Polyvinylcarbazole (PVK) 60 mg, Compound 1-8 Facial Form (1-8F) 2.0 mg and 1-8 Meridio Form (1-8M) 1.0 mg are dissolved in 6 ml of dichlorobenzene, and the target solution coating solution ( 1-1) was obtained.

(Preparation of dispersion coating solution)
300 mg of polyvinylcarbazole (PVK) and the compounds described in Table 1 were dissolved in 30 ml of tetrahydrofuran (THF). Next, 50 ml of ethanol / THF (9/1) solution was vigorously stirred, and 10 ml of the above THF solution was added dropwise thereto using a microsyringe to obtain a primary dispersion. The primary dispersion was stirred and slowly concentrated in a nitrogen stream over about 6 hours until the volume was almost halved to obtain the desired dispersion coating liquids (1-2) to (1-6). (Average particle size 60 nm).

[Production of Organic EL Elements 1-1 to 1-6]
After patterning on a substrate (NH-Techno Glass NA-45) on which a 100 nm × 100 mm × 1.1 mm glass substrate (ITO indium tin oxide) was deposited as an anode was provided, this ITO transparent electrode was provided. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  On this transparent support substrate, a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water at 3000 rpm for 30 seconds. After forming a film by spin coating, the film was dried at 200 ° C. for 1 hour to provide a first hole transport layer having a thickness of 30 nm. Next, the solution coating solution (1-1) was spin-coated on this transparent support substrate at 1000 rpm for 30 seconds (film thickness: about 100 nm) and vacuum-dried at 60 ° C. for 1 hour to obtain a light emitting layer.

This was attached to a vacuum deposition apparatus, and then the vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa, and 0.5 nm of lithium fluoride was deposited as a cathode buffer layer and 110 nm of aluminum was deposited as a cathode to form a cathode. -1 was produced.

  The same method as for the organic EL element 1-1 except that the solution-like coating liquid (1-1) in the production of the organic EL element 1-1 was changed to the dispersion-like coating liquids (1-2) to (1-6). Organic EL elements 1-2 to 1-6 were produced.

[Evaluation of Organic EL Elements 1-1 to 1-6]
The organic EL elements 1-1 to 1-6 were evaluated as follows, and the results are shown in Table 1.

《External extraction quantum efficiency》
About the produced organic EL element, the external extraction quantum efficiency (%) when a ^2.5 mA / cm ² constant current was applied in a dry nitrogen gas atmosphere at 23 ° C. was measured. For the measurement, a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing) was used in the same manner.

"lifespan"
When driving at a constant current of ^2.5 mA / cm ² , the time required for the luminance to drop to half of the luminance immediately after the start of light emission (initial luminance) was measured, and this was calculated as the half-life time (τ 0.5). As an index of life. For the measurement, a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing) was used.

  The measurement results of the external extraction quantum efficiency and lifetime of the organic EL elements 1-1 to 1-6 are shown in Table 1 as relative values when the organic EL element 1-1 is 100.

  From Table 1, it is clear that the organic EL device of the present invention is superior in both external quantum efficiency and lifetime as compared with the comparison.

Example 2
(Preparation of solution coating solution)
Polyvinylcarbazole (PVK) 60 mg, Compound 1-9 Facial Form (1-9F) 2.0 mg, 1-9 Meridio Form (1-9M) 1.0 mg are dissolved in 6 ml of dichlorobenzene, and the target solution coating solution ( 2-1) was obtained.

(Preparation of dispersion coating solution)
Polyvinylcarbazole (PVK) 12 g, the compound shown in Table 2 and 100 ml of 1,2-dichloroethane were added to a pot of CLEARMIX CLM (M Technique Co., Ltd.), and dissolved by stirring. 270 ml of pure water was added thereto and emulsified at 20000 rpm for 5 minutes. Thereafter, 1,2-dichloroethane was washed away to obtain a fine particle aqueous dispersion (average particle size 40 nm). Next, according to a conventional method, the solvent was replaced with n-butyl alcohol to obtain the desired dispersion coating liquids (2-2) to (2-6). (Average particle size 50 nm).

[Production of Organic EL Elements 2-1 to 2-6]
After patterning on a substrate (NH-Techno Glass NA-45) on which a 100 nm × 100 mm × 1.1 mm glass substrate (ITO indium tin oxide) was deposited as an anode was provided, this ITO transparent electrode was provided. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  A solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water on this transparent support substrate at 3000 rpm for 30 seconds. After film formation by a spin coating method, the film was dried at 200 ° C. for 1 hour to provide a 30-nm first hole transport layer. Subsequently, the solution-form coating liquid (2-1) was spin-coated on this transparent support substrate under the conditions of 1000 rpm for 30 seconds (film thickness: about 100 nm) and vacuum-dried at 60 ° C. for 1 hour to obtain a light emitting layer.

This is attached to a vacuum deposition apparatus, and then the vacuum chamber is decompressed to 4 × 10 ⁻⁴ Pa, lithium fluoride 0.5 nm is deposited as a cathode buffer layer, and aluminum 110 nm is deposited as a cathode to form a cathode, and an organic EL device 2-1.

  Except for changing the liquid coating liquid (2-1) to the dispersed coating liquids (2-2) to (2-6) as in the production of the organic EL element 2-1, the same method as the organic EL element 2-1. Organic EL elements 2-2 to 2-6 were produced.

[Evaluation of Organic EL Elements 2-1 to 2-6]
Evaluation of the organic EL elements 2-1 to 2-6 was performed in the same manner as in Example 1, and the results are shown in Table 2. Both external extraction quantum efficiency and lifetime are shown as relative values when the organic EL element 2-1 is set to 100.

  From Table 2, it is clear that the organic EL device of the present invention is superior in both external quantum efficiency and lifetime as compared with the comparison.

Example 3
(Preparation of solution coating solution)
10 mg of 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (α-NPD), 6.6 mg of compound 1-14 facial form (1-14F) and 1-14 meridio form (1 -14M) 3.4 mg was dissolved in 6 ml of dichlorobenzene to obtain the desired solution coating solution (3-1).

(Preparation of dispersion coating solution)
24 g of 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (α-NPD) and the compounds shown in Table 3 were added to 300 ml of ethyl alcohol, and this was added to an apex mill manufactured by Sakai Kogyo. The dispersion liquid of interest (3-2) to (3-6) was obtained by dispersing at a peripheral speed of 8 m / sec for 20 minutes using 0.05 mm beads. (Average particle size 35 nm).

[Production of Organic EL Elements 3-1 to 3-6]
After patterning on a substrate (NH-Techno Glass NA-45) on which a 100 nm × 100 mm × 1.1 mm glass substrate (ITO indium tin oxide) was deposited as an anode was provided, this ITO transparent electrode was provided. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  A solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water on this transparent support substrate at 3000 rpm for 30 seconds. After film formation by a spin coating method, the film was dried at 200 ° C. for 1 hour to provide a 30-nm first hole transport layer. Next, the solution coating solution (3-1) was spin-coated on this transparent support substrate at 1000 rpm for 30 seconds (film thickness: about 100 nm) and vacuum-dried at 60 ° C. for 1 hour to obtain a light emitting layer.

This is attached to a vacuum deposition apparatus, and then the vacuum chamber is decompressed to 4 × 10 ⁻⁴ Pa, lithium fluoride 0.5 nm is deposited as a cathode buffer layer, and aluminum 110 nm is deposited as a cathode to form a cathode, and an organic EL device 3-1.

  The same method as for the organic EL element 3-1, except that the solution coating liquid (3-1) in the production of the organic EL element 3-1 was changed to the dispersion coating liquids (3-2) to (3-6). Organic EL elements 3-2 to 3-6 were produced.

[Evaluation of Organic EL Elements 3-1 to 3-6]
Evaluation of the organic EL elements 3-1 to 3-6 was performed in the same manner as in Example 1, and the results are shown in Table 3. Both the external extraction quantum efficiency and lifetime are shown as relative values when the organic EL element 3-1 is 100.

  From Table 3, it is clear that the organic EL device of the present invention is superior in both external extraction quantum efficiency and lifetime as compared with the comparison.

Example 4
[Production of organic EL full-color display device]
FIG. 1 shows a schematic configuration diagram of an organic EL full-color display device. After patterning at a pitch of 100 μm on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) formed by forming a 100 nm ITO transparent electrode (102) on a glass substrate 101 as an anode, non-between the ITO transparent electrodes on this glass substrate. A photosensitive polyimide partition 103 (width 20 μm, thickness 2.0 μm) was formed by photolithography. A hole injection layer composition having the following composition is ejected and injected between polyimide partition walls on the ITO electrode using an inkjet head (manufactured by Epson Corporation; MJ800C), and a hole having a film thickness of 40 nm is obtained by drying at 200 ° C. for 10 minutes. An injection layer 104 was produced. A blue light-emitting layer composition, a green light-emitting layer composition, and a red light-emitting layer composition prepared by the following methods were respectively discharged and injected onto the hole injection layer using an inkjet head in the same manner. 105B, 105G, 105R). Finally, Al (106) was vacuum-deposited as a cathode so as to cover the light emitting layer 105, and an organic EL element was produced.

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

(Hole injection layer composition)
PEDOT / PSS mixed water dispersion (1.0% by mass) 20 parts by mass Water 65 parts by mass Ethoxyethanol 10 parts by mass Glycerin 5 parts by mass (Preparation of blue light emitting layer composition)
To a pot of CLEARMIX CLM (M Technique Co., Ltd.), add 12 g of polyvinylcarbazole (PVK), 480 mg of compound 1-14 facial, 240 mg of compound 1-14 meridio and 100 ml of 1,2-dichloroethane, and stir. And dissolved. 270 ml of pure water was added thereto and emulsified at 20000 rpm for 5 minutes. Thereafter, 1,2-dichloroethane was washed away to obtain a fine particle aqueous dispersion (average particle size 40 nm). Next, the solvent was replaced with n-butyl alcohol according to a conventional method to obtain the target blue light emitting layer composition.

(Preparation of green light emitting layer composition)
To a pot of Claremix CLM (M Technique Co., Ltd.), add 12 g of polyvinylcarbazole (PVK), 480 mg of compound 1-8 facial, 240 mg of compound 1-8 meridio and 100 ml of 1,2-dichloroethane and stir. And dissolved. 270 ml of pure water was added thereto and emulsified at 20000 rpm for 5 minutes. Thereafter, 1,2-dichloroethane was washed away to obtain a fine particle aqueous dispersion (average particle size 40 nm). Next, the solvent was replaced with n-butyl alcohol according to a conventional method to obtain the target green light emitting layer composition. (Average particle size 50 nm).

(Preparation of red light emitting layer composition)
To a pot of Claremix CLM (M Technique Co., Ltd.), add 12 g of polyvinylcarbazole (PVK), 480 mg of compound 1-9 facial, 240 mg of compound 1-9 meridio and 100 ml of 1,2-dichloroethane and stir. And dissolved. 270 ml of pure water was added thereto and emulsified at 20000 rpm for 5 minutes. Thereafter, 1,2-dichloroethane was washed away to obtain a fine particle aqueous dispersion (average particle size 40 nm). Next, the solvent was replaced with n-butyl alcohol according to a conventional method to obtain a target red light emitting layer composition. (Average particle size 50 nm).

Example 5
[Production of lighting device using white organic EL element]
In the organic EL device 1-3 produced in Example 1, the 1-8 facial body and 1-8 meridio body used for the light emitting layer were replaced with 1-8 (facial body and meridio body), 1-14 (facial body and An organic EL device 5-1 was produced in the same manner as the organic EL device 1-3 except that the mixture was changed to a mixture of 1-9 (facial body and meridio body). When a 10 V DC voltage was applied to the organic EL element 5-1, almost white light emission was obtained.

The schematic block diagram of an organic electroluminescent full color display apparatus is shown.

Explanation of symbols

101 Glass substrate 102 ITO transparent electrode 103 Partition 104 Hole injection layer 105B, 105G, 105R Light emitting layer

Claims (15)

In an organic electroluminescent element having a cathode and an anode on a substrate and having a plurality of organic layers therebetween, at least one of the organic layers is a layer formed using a dispersion liquid, and any of the organic layers An organic electroluminescence device comprising a compound consisting of crab isomers. 2. The organic electroluminescence device according to claim 1, wherein the layer formed using the dispersion contains a compound composed of an isomer. The organic electroluminescence device according to claim 2, wherein the dispersion is prepared from a dispersion of a compound comprising an isomer. The organic luminescence device according to claim 1, wherein the isomer is a structural isomer. The organic luminescence device according to any one of claims 1 to 3, wherein the isomer is a stereoisomer. The organic electroluminescent device according to any one of claims 1 to 5, wherein the compound comprising the isomer is a phosphorescent complex, a host compound, or a hole transport material. The organic electroluminescence device according to claim 1, wherein the abundance ratio of one isomer in the compound consisting of the isomers is 0.001 to 0.5. The organic electroluminescent element according to claim 1, wherein one of the organic layers is a light emitting layer containing a phosphorescent complex. The organic electroluminescent device according to claim 8, wherein the phosphorescent complex is a compound composed of an isomer. 10. The organic electroluminescence device according to claim 8, wherein the phosphorescent complex is an iridium complex. Light emission is white, The organic electroluminescent element of any one of Claims 1-10 characterized by the above-mentioned. When manufacturing the organic electroluminescent element of any one of Claims 1-11, it forms into a film by the apply | coating method using a dispersion liquid, The manufacturing method of the organic electroluminescent element characterized by the above-mentioned. The method for producing an organic electroluminescent element according to claim 12, wherein the coating method is an inkjet method. A display device using the organic electroluminescence element according to claim 11. An organic electroluminescent element according to claim 11 is used.

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