WO2012147990A1

WO2012147990A1 - Organic electroluminescence element and method for producing same

Info

Publication number: WO2012147990A1
Application number: PCT/JP2012/061628
Authority: WO
Inventors: 上谷　保則
Original assignee: 住友化学株式会社
Priority date: 2011-04-26
Filing date: 2012-04-25
Publication date: 2012-11-01
Also published as: JP2013008935A; JP5834539B2; TW201251173A

Abstract

The present invention pertains to a method for producing an organic electroluminescence element involving forming an anode, forming a light-emitting layer, and forming a functional layer by applying a coating liquid containing a particulate electron-transporting material, and further forming a cathode by a coating method.

Description

Organic electroluminescence device and method for producing the same

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

In recent years, research and development of organic functional devices using organic semiconductor materials instead of inorganic semiconductor materials such as silicon have been actively conducted in the electronics field. One example of such an organic functional device is an organic electroluminescence element (hereinafter sometimes referred to as an organic EL element). The organic EL element is formed, for example, by sequentially laminating an anode, a light emitting layer, an electron transport layer, and a cathode (see, for example, JP-A-2005-63834).

In the organic EL element described above, it has been studied to sequentially form an electron transport layer and a cathode by a coating method. May dissolve again. Due to such re-dissolution of the electron transport layer, the characteristics of the produced organic EL device may be deteriorated.
The objective of this invention is providing the manufacturing method of the organic EL element which can prevent the functional layer provided in the lower layer of a cathode dissolving in the coating liquid used when forming a cathode by the apply | coating method. is there.
The present invention includes the following aspects [1] to [8].
[1] An organic electroluminescence device in which an anode is formed, a light emitting layer is formed, a functional layer is formed by coating a coating liquid containing a particulate electron transporting material, and a cathode is further formed by a coating method Manufacturing method.
[2] The method for producing an organic electroluminescence element according to [1], wherein the particulate electron transporting material is particulate zinc oxide.
[3] The coating liquid containing the particulate electron transport material is at least one selected from the group consisting of an alkali metal complex, an alkali metal salt, an alkaline earth metal complex, and an alkaline earth metal salt. The manufacturing method of the organic electroluminescent element of [1] or [2] containing a seed.
[4] The method for producing an organic electroluminescent element according to any one of [1] to [3], wherein the cathode includes polythiophene and / or a polythiophene derivative.
[5] The method for producing an organic electroluminescent element according to any one of [1] to [4], wherein the cathode includes polyaniline and / or a polyaniline derivative.
[6] The method for manufacturing an organic electroluminescence element according to any one of [1] to [4], wherein the cathode includes nanoparticles of a conductive substance, nanowires of a conductive substance, or nanotubes of a conductive substance.
[7] An organic electroluminescence device having a structure in which a light emitting layer, a functional layer, and a cathode are laminated in this order on an anode on a support substrate, wherein the functional layer contains a particulate electron transport material. An organic electroluminescence element formed by coating film formation.
[8] A display device comprising a reflective display body and a transmissive display body disposed on the reflective display body,
The reflective display has a reflective display layer capable of selectively displaying the first color and the second color according to a predetermined position;
The transmissive display has an organic electroluminescence element produced by the method according to any one of [1] to [6] or an organic electroluminescence element of [7] as a pixel light source,
The organic electroluminescence element is a display device in which an anode and a cathode are realized by electrodes exhibiting optical transparency.

Hereinafter, the present invention will be described in detail.
<1> Organic EL Element The organic EL element of the present invention is an organic electroluminescence element having a configuration in which a light emitting layer, a functional layer, and a cathode are laminated in this order on an anode, and the functional layer has a particulate electron transport. It is formed by coating a coating solution containing a functional material. The anode is usually laminated on a support substrate.
At least one of the anode and the cathode is constituted by a transparent or translucent electrode. In the case of a so-called bottom emission type organic EL element in which light emitted from the light emitting layer is emitted through the support substrate, the anode is constituted by a transparent or translucent electrode. In the case of a so-called top emission type organic EL element in which light emitted from the light emitting layer is emitted in a direction away from the support substrate, the cathode is constituted by a transparent or translucent electrode. In the case of a see-through type organic EL element in which light emitted from the light emitting layer is emitted through the support substrate and also emitted in a direction away from the support substrate, the anode and the cathode are made of transparent or translucent electrodes. Composed.
(Support substrate)
The support substrate may be any substrate that does not change chemically when an organic EL element is produced. Examples of the material include glass, plastic, polymer film, and silicon. In the case of the top emission type organic EL element, an opaque substrate can be used as the support substrate. However, in the case of the bottom emission type and see-through type organic EL elements, the support substrate is transparent or semi-transparent. A transparent substrate is used.
(anode)
For the anode, a conductive metal oxide film, a metal thin film, a conductive film containing an organic substance, or the like is used. Specifically, the anode includes indium oxide, zinc oxide, tin oxide, indium tin oxide (abbreviated as ITO), indium zinc oxide (abbreviated as IZO), gold, platinum, silver, Thin films such as copper, aluminum, polyaniline and derivatives thereof, and polythiophene and derivatives thereof are used. Among these, a thin film of ITO, IZO, or tin oxide is preferably used for the anode. In the organic EL element configured to extract light from the anode, for example, a transparent or translucent electrode in which the film thickness of the above-described anode is set to a thickness that allows light to pass therethrough is used as the anode.
The thickness of the anode is usually 1 nm to 1 mm, preferably 10 nm to 100 μm, and more preferably 20 nm to 10 μm.
(Light emitting layer)
The light emitting layer is usually formed of an organic substance that mainly emits fluorescence and / or phosphorescence, or an organic substance and a dopant that assists the organic substance. The light emitting layer is preferably formed by a coating method. The light emitting layer preferably contains a polymer compound, may contain one kind of polymer compound alone, or may contain two or more kinds in combination, and further comprises a conjugated polymer compound. preferable. In order to enhance the charge transporting property of the light emitting layer, an electron transporting compound and / or a hole transporting compound may be mixed and used in the light emitting layer. Examples of the light emitting material constituting the light emitting layer include the following dye materials, metal complex materials, polymer materials, and dopant materials.
Dye-type material Examples of the dye-type material include cyclopentamine derivatives, tetraphenylbutadiene derivative compounds, triphenylamine derivatives, oxadiazole derivatives, pyrazoloquinoline derivatives, distyrylbenzene derivatives, distyrylarylene derivatives, pyrrole derivatives, Examples thereof include thiophene ring compounds, pyridine ring compounds, perinone derivatives, perylene derivatives, oligothiophene derivatives, trifumanylamine derivatives, oxadiazole dimers, pyrazoline dimers, quinacridone derivatives, and coumarin derivatives.
Metal complex material As a metal complex material, for example, a central metal includes a typical metal or transition metal such as Al, Zn, Be, Ir, Pt, or a rare earth metal such as Tb, Eu, Dy, and a ligand. Examples thereof include metal complexes having an oxadiazole, thiadiazole, phenylpyridine, phenylbenzimidazole, quinoline structure, and the like. Examples of metal complex materials include metal complexes that emit light from triplet excited states such as iridium complexes and platinum complexes, aluminum quinolinol complexes, benzoquinolinol beryllium complexes, benzoxazolyl zinc complexes, benzothiazole zinc complexes, azomethyl zinc A complex, a porphyrin zinc complex, a europium complex, etc. can be mentioned.
Polymeric materials Polymeric materials include polyparaphenylene vinylene derivatives, polythiophene derivatives, polyparaphenylene derivatives, polysilane derivatives, polyacetylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, the above-mentioned dye materials and metal complex light emitting materials. A polymerized product can be exemplified.
Among the above light-emitting materials, examples of materials that emit blue light include distyrylarylene derivatives, oxadiazole derivatives, and polymers thereof, polyvinylcarbazole derivatives, polyparaphenylene derivatives, and polyfluorene derivatives. Of these, polymer materials such as polyvinyl carbazole derivatives, polyparaphenylene derivatives, and polyfluorene derivatives are preferred.
Examples of materials that emit green light include quinacridone derivatives, coumarin derivatives, and polymers thereof, polyparaphenylene vinylene derivatives, polyfluorene derivatives, and the like. Of these, polymer materials such as polyparaphenylene vinylene derivatives and polyfluorene derivatives are preferred.
Examples of the material that emits red light include a coumarin derivative, a thiophene ring compound, a polymer thereof, a polyparaphenylene vinylene derivative, a polythiophene derivative, and a polyfluorene derivative. Among these, polymer materials such as polyparaphenylene vinylene derivatives, polythiophene derivatives, and polyfluorene derivatives are preferable.
Dopant material Examples of the dopant material include perylene derivatives, coumarin derivatives, rubrene derivatives, quinacridone derivatives, squalium derivatives, porphyrin derivatives, styryl dyes, tetracene derivatives, pyrazolone derivatives, decacyclene, phenoxazone, and the like.
The thickness of the light emitting layer is usually 1 nm to 100 μm, preferably 2 nm to 1000 nm, more preferably 2 nm to 200 nm, still more preferably 5 nm to 500 nm, and particularly preferably 20 nm to 200 nm.
(Functional layer)
The functional layer is provided between the light emitting layer and the cathode, and is formed by coating a coating solution containing a particulate electron transporting material. First, when a coating liquid containing a particulate electron transporting material is formed into a film and then dried, a functional layer that is difficult to dissolve in a solvent such as water can be obtained. When a cathode or the like is formed on such a functional layer by a coating method, the functional layer can be prevented from being dissolved in the coating liquid, so that formation by a coating method such as a cathode is facilitated. In the present invention, the coating solution includes a dispersion such as an emulsion (emulsion) or a suspension (suspension).
Examples of the particulate electron transport material include zinc oxide, titanium oxide, zirconium oxide, tin oxide, indium oxide, ITO (indium tin oxide), FTO (fluorine-doped tin oxide), and GZO (gallium-doped zinc oxide). , ATO (antimony-doped tin oxide), AZO (aluminum-doped zinc oxide), among these, zinc oxide, GZO (gallium-doped zinc oxide), and AZO (aluminum-doped zinc oxide) are preferable, and from the viewpoint of price Zinc oxide is more preferred.
In forming the functional layer, it is preferable to form a coating liquid containing particulate zinc oxide, GZO or AZO (preferably zinc oxide) to form the functional layer. As such an electron transporting material, it is preferable to use so-called nanoparticles of zinc oxide, GZO or AZO (preferably zinc oxide), and electrons consisting only of nanoparticles of zinc oxide, GZO or AZO (preferably zinc oxide). It is more preferable to form a functional layer using a transport material. The average particle diameter corresponding to the spheres of the electron transport material, particulate zinc oxide, GZO and AZO is preferably 1 nm to 1000 nm, more preferably 10 nm to 100 nm. The average particle diameter is measured by a laser light scattering method or X-ray diffraction.
By providing a functional layer containing a particulate electron-transporting material between the cathode and the light-emitting layer, it is possible to prevent peeling of the cathode and increase the efficiency of electron injection from the cathode to the light-emitting layer. The functional layer is preferably provided in contact with the light emitting layer, and more preferably provided in contact with the cathode. By providing the functional layer including the electron transporting material as described above, it is possible to prevent the cathode from being peeled off and to further increase the efficiency of electron injection from the cathode to the light emitting layer. By providing such a functional layer, an organic EL element with high reliability and high luminous efficiency can be realized.
The functional layer containing the particulate electron transporting material functions as a so-called electron transport layer and / or electron injection layer. By providing such a functional layer, the efficiency of electron injection from the cathode is increased, the injection of holes from the light emitting layer is prevented, the electron transport capability is increased, and the cathode is formed by a coating method. It is possible to protect the light emitting layer from erosion by the coating solution used and to suppress deterioration of the light emitting layer.
The functional layer containing the particulate electron transporting material is preferably composed of a material having high wettability with respect to a coating solution used when the cathode is applied and formed. Specifically, the functional layer containing the particulate electron transport material preferably has higher wettability with respect to the coating liquid than the wettability of the light emitting layer with respect to the coating liquid used when the cathode is applied and formed. The wettability of the functional layer or the light emitting layer with respect to the coating liquid can be evaluated by, for example, the contact angle between the coating liquid and the functional layer or the light emitting layer. The smaller the contact angle, the higher the wettability. By coating and forming the cathode on such a functional layer, when forming the cathode, the coating liquid can be well spread on the surface of the functional layer, and a cathode having a uniform film thickness can be formed.
The coating liquid containing the particulate electron transport material is at least one selected from the group consisting of an alkali metal complex, an alkali metal salt, an alkaline earth metal complex, and an alkaline earth metal salt (hereinafter, It may preferably be referred to as “alkaline metal, alkaline earth metal complex or salt”. By using such a coating solution, a functional layer containing an alkali metal, alkaline earth metal complex or salt can be formed. By containing an alkali metal, alkaline earth metal complex or salt, the electron injection efficiency can be further increased.
The alkali metal or alkaline earth metal complex or salt is preferably soluble in the solvent of the coating solution. Examples of the alkali metal include lithium, sodium, potassium, rubidium, and cesium. Examples of the alkaline earth metal include magnesium, calcium, strontium, and barium. Examples of the complex include β-diketone complexes, and examples of the salt include alkoxide, phenoxide, carboxylate, carbonate, and hydroxide.
Specific examples of alkali metal or alkaline earth metal complexes or salts include sodium acetylacetonate, cesium acetylacetonate, calcium bisacetylacetonate, barium bisacetylacetonate, sodium methoxide, sodium phenoxide, sodium tert-butoxide Sodium tert-pentoxide, sodium acetate, sodium citrate, cesium carbonate, cesium acetate, sodium hydroxide, cesium hydroxide and the like.
Among these, sodium acetylacetonate, cesium acetylacetonate, and cesium acetate are preferable, and cesium acetate is more preferable from the viewpoint of solubility in a coating solution containing a particulate electron transporting material.
In the coating solution containing the particulate electron transporting material, the total weight of the alkali metal, alkaline earth metal complex or salt is 1 to 1000 parts by weight when the particulate electron transporting material is 100 parts by weight. It is preferably 5 to 500 parts by weight.
(cathode)
The cathode can take the form of a single layer or a stack of a plurality of layers. In this embodiment, the cathode is formed by a coating method (wet process). The coating liquid used when forming the cathode by a coating method includes a constituent material of the cathode and a solvent. The cathode preferably contains a polymer compound exhibiting conductivity, and is preferably made of a polymer compound substantially exhibiting conductivity. Examples of the constituent material of the cathode include organic materials such as polyaniline and derivatives thereof, polythiophene and derivatives thereof, and polypyrrole and derivatives thereof.
The cathode is preferably composed of polythiophene and / or polythiophene derivatives, and is preferably substantially composed of polythiophene and / or polythiophene derivatives. The cathode is preferably composed of polyaniline and / or a polyaniline derivative, and is preferably composed of polyaniline and / or a polyaniline derivative.
Specific examples of polythiophene and derivatives thereof include compounds containing one or more of the following structural formulas.

Specific examples of polypyrrole and derivatives thereof include compounds containing one or more of a plurality of structural formulas shown below.

Specific examples of polyaniline and derivatives thereof include compounds containing one or more of the following structural formulas.

Among the constituent materials of the above cathode, PEDOT / PSS composed of poly (3,4-ethylenedioxythiophene) (PEDOT) and poly (4-styrenesulfonic acid) (PSS) has a high luminous efficiency. It is suitably used as a constituent material for the cathode.
The cathode is not limited to the coating liquid containing the organic material, but an emulsion (emulsion) or suspension (suspension) containing conductive material nanoparticles, conductive material nanowires, or conductive material nanotubes. Alternatively, it may be formed by a coating method using a dispersion such as a metal paste, a low melting point metal in a molten state, or the like. Examples of the conductive substance include metals such as gold and silver, oxides such as ITO (indium tin oxide), and carbon nanotubes. The cathode may be composed only of nanoparticles or nanofibers of a conductive material. However, as shown in Japanese Translation of PCT International Publication No. 2010-525526, the cathode is composed of conductive particles or nanofibers. You may have the structure disperse | distributed and arrange | positioned in predetermined media, such as a polymer.
The organic EL element is not limited to the element configuration described above, and an additional layer may be further provided between the anode and the cathode. That is, an additional layer may be provided between the anode and the light emitting layer, between the light emitting layer and the functional layer, and between the functional layer and the cathode. Examples of such an additional layer include a hole transport layer that transports holes, an electron transport layer that transports electrons, and a buffer layer. For example, the hole transport layer is provided between the anode and the light emitting layer, the electron transport layer is provided between the light emitting layer and the functional layer, and the buffer layer is provided, for example, between the cathode and the functional layer. By providing the buffer layer, planarization of the surface and charge injection can be promoted.
As the material used for the hole transport layer or the electron transport layer as the additional layer, the above-described electron donating compound and electron accepting compound can be used, respectively. As a material used for the buffer layer as an additional layer, an alkali metal such as lithium fluoride, a halide of an alkaline earth metal, an oxide, or the like can be used.
<2> Method for Producing Organic EL Element In the method for producing an organic EL element of the present invention, an anode is formed, a light emitting layer is formed, and a coating liquid containing a particulate electron transporting material is applied and formed into a film. A layer is formed, and a cathode is further formed by a coating method. Thus, an organic EL element is formed by forming each layer in order of an anode, a light emitting layer, a functional layer, and a cathode.
<Anode formation process>
The anode is formed by depositing the anode material described as an example on the above-described support substrate by vacuum deposition, sputtering, ion plating, plating, or the like. The anode may be formed by a coating method using a coating liquid containing an organic material such as polyaniline and its derivative, polythiophene and its derivative, a metal ink, a metal paste, a molten low melting point metal, or the like.
<Light emitting layer forming step>
The light emitting layer is preferably formed by a coating method. The light emitting layer can be formed, for example, by a coating method using a coating solution containing the constituent material of the light emitting layer and a solvent. For example, the light emitting layer is formed by a coating method using a coating solution containing a polymer phosphor compound and a solvent. be able to.
Examples of the solvent include hydrocarbon solvents such as toluene, xylene, mesitylene, tetralin, decalin, bicyclohexyl, n-butylbenzene, s-butylbezen, and t-butylbenzene, carbon tetrachloride, chloroform, dichloromethane, dichloroethane, and chlorobutane. , Halogenated saturated hydrocarbon solvents such as bromobutane, chloropentane, bromopentane, chlorohexane, bromohexane, chlorocyclohexane, bromocyclohexane, halogenated unsaturated hydrocarbon solvents such as chlorobenzene, dichlorobenzene, trichlorobenzene, tetrahydrofuran, And ether solvents such as tetrahydropyran.
The coating liquid used in the present invention may contain two or more kinds of solvents, and may contain two or more kinds of the solvents exemplified above.
As a method of applying a coating solution containing the constituent material of the light emitting layer, a spin coating method, a casting method, a micro gravure coating method, a gravure coating method, a bar coating method, a roll coating method, a wire bar coating method, a dip coating method, Examples of the spray coating method, screen printing method, flexographic printing method, offset printing method, ink jet printing method, dispenser printing method, nozzle coating method, capillary coating method, and the like include spin coating method and flexographic method. A printing method, an inkjet printing method, and a dispenser printing method are preferable.
<Functional layer formation process>
As described above, a functional layer containing a particulate electron transport material is formed between the light emitting layer and the cathode. That is, after the formation of the light emitting layer and before the formation of the cathode, the functional layer is formed by coating and forming a coating liquid containing the above-described particulate electron transporting material on the light emitting layer.
When the functional layer containing the particulate electron transporting material is provided in contact with the light emitting layer, the functional layer is formed by applying the coating solution on the surface of the light emitting layer. When forming the functional layer, it is preferable to use a coating solution that causes little damage to a layer to which the coating solution is applied (such as a light emitting layer). Specifically, a layer to which the coating solution is applied (such as a light emitting layer). It is preferable to use a coating solution that hardly dissolves.
The coating liquid used for coating and forming the functional layer includes a solvent and the particle electron transport material described above. Examples of the solvent for the coating solution include water and alcohol. Specific examples of the alcohol include methanol, ethanol, isopropanol, butanol, ethylene glycol, propylene glycol, butoxyethanol, methoxybutanol and the like. The coating liquid used in the present invention may contain two or more kinds of solvents, and may contain two or more kinds of the solvents exemplified above.
In forming the functional layer, it is preferable to dry the formed thin film after forming the coating solution. The thin film is dried, for example, by vacuum drying, heat drying, or natural drying. By drying the thin film in this manner, the functional layer can be insolubilized with respect to the coating liquid applied on the functional layer.
<Cathode formation process>
The cathode is formed on the surface of the functional layer or the like by a coating method. Specifically, the cathode is formed by applying a coating liquid containing a solvent and the above-described cathode constituent material onto the surface of a functional layer or the like. Examples of the solvent for the coating solution used for forming the cathode include hydrocarbon solvents such as toluene, xylene, mesitylene, tetralin, decalin, bicyclohexyl, n-butylbenzene, s-butylbezen, t-butylbenzene, and the like. Halogenated saturated hydrocarbon solvents such as carbon chloride, chloroform, dichloromethane, dichloroethane, chlorobutane, bromobutane, chloropentane, bromopentane, chlorohexane, bromohexane, chlorocyclohexane, bromocyclohexane, halogens such as chlorobenzene, dichlorobenzene, and trichlorobenzene Unsaturated hydrocarbon solvents, ether solvents such as tetrahydrofuran and tetrahydropyran, water, alcohols and the like. Specific examples of the alcohol include methanol, ethanol, isopropanol, butanol, ethylene glycol, propylene glycol, butoxyethanol, methoxybutanol and the like. The coating liquid used in the present invention may contain two or more kinds of solvents, and may contain two or more kinds of the solvents exemplified above.
When the cathode is formed using a coating solution that damages the light emitting layer or the functional layer, for example, the cathode has a two-layer structure, and the first thin film does not damage the light emitting layer or the functional layer. It may be formed using a coating solution, and then the second thin film may be formed using a coating solution capable of damaging the light emitting layer and the functional layer. Thus, by using a two-layer cathode, even if the second thin film is formed using a coating solution that can damage the light-emitting layer or the functional layer, the first thin film functions as a protective layer. Therefore, damage to the light emitting layer and the functional layer can be suppressed. For example, since the functional layer made of zinc oxide is easily damaged by an acidic solution, when forming a cathode on the functional layer made of zinc oxide, the first thin film is formed using a neutral coating solution. Then, a two-layered cathode may be formed by forming a second-layer thin film using an acidic solution.
In the present embodiment, it is preferable to form the remaining constituent elements excluding the anode among the constituent elements of the organic EL element by a coating method. Thus, by forming each element by a simple coating method as a process, an organic EL element can be easily formed, productivity can be improved, and the cost of element manufacture can be reduced. In addition to the anode, it is more preferable to form all components constituting the organic EL element by a coating method. Thus, by forming all the elements by a simple coating method as a process, an organic EL element can be easily formed, productivity can be improved, and the cost of element manufacture can be reduced.
The organic EL element described above can be suitably used for a curved or flat illumination device, for example, a planar light source used as a light source of a scanner, and a display device. As described above, an apparatus including an organic EL element that can be manufactured by a simple process can be manufactured at a low cost by a simple process as in the case of the organic EL element.
Examples of the display device including an organic EL element include a segment display device and a dot matrix display device. The dot matrix display device includes an active matrix display device and a passive matrix display device. An organic EL element is used as a light emitting element constituting each pixel in an active matrix display device and a passive matrix display device. The organic EL element is used as a light emitting element constituting each segment in the segment display device, and is used as a backlight in the liquid crystal display device.
The display device including the organic EL element is a display device including a reflective display body and a transmissive display body disposed on the reflective display body, and the reflective display body is at a predetermined position. Accordingly, it has a reflective display layer that can selectively display the first color and the second color, and the transmissive display has the organic EL element described above as a pixel light source. The organic EL element includes a display device in which an anode and a cathode are realized by an electrode having optical transparency.
An organic EL element in which the anode and the cathode are realized by an electrode having optical transparency is an optically transparent element. The transmissive display body constitutes a transmissive display body, for example, by arranging a large number of organic EL elements exhibiting light transmittance as light sources of pixels on a substrate exhibiting light transmittance.
The reflective display body is realized by so-called electronic paper or the like. This reflection type display body includes a reflection type display body layer capable of selectively displaying the first color and the second color. The first color and the second color are not particularly limited as long as the colors are different. For example, one color is white and the other color is black. The reflective display layer can display, for example, image information, for example, in black and white, by selectively displaying the first color and the second color according to a predetermined position.
This display device includes control means for controlling display states of the reflective display body and the transmissive display body. For example, when the image information to be displayed on the display device is a so-called moving image that changes with time, the control means displays the entire surface of the reflective display body in black, displays the moving image on the transmissive display body, When the image information to be displayed on the display device is a still image such as character information that does not change over time, the still image is displayed on the reflective display body, and the transmissive display body is made non-luminous and transparent. Control to maintain. By controlling in this way, an organic EL element having a high response is used as a light source even when a device that is not highly responsive, such as electronic paper, and is not suitable for moving image display is used as a reflective display. Since the moving image is displayed on the used transmissive display body suitable for moving image display, the moving image can be appropriately displayed. On the other hand, although an apparatus such as electronic paper is generally not suitable for moving image display, since power consumption is small, power consumption of the entire display device can be suppressed by displaying a still image on a reflective display. A still image does not mean that image information does not change completely over time. For example, when displaying character information, the image information changes when the character information is updated according to the user's action. Such image information is also included in the still image.
Such a display device is realized by, for example, a device described in Japanese Patent Application Laid-Open No. 2004-30321.
When the cathode and the anode are constituted by transparent or translucent electrodes, an organic EL element exhibiting light transmittance can be constituted. Such an organic EL element can be easily configured as a parallel-type or series-type multi-junction element by being superimposed with a light-transmitting organic EL element or a light-transmitting organic EL element. Have advantages.

Examples will be shown below for illustrating the present invention in more detail, but the present invention is not limited to these examples.
-Method for measuring molecular weight-
In the synthesis examples, the number average molecular weight (Mn) and the weight average molecular weight (Mw) were determined in terms of polystyrene by gel permeation chromatography (GPC). Specifically, using a column in which three TSKgel SuperHM-H (manufactured by Tosoh) are connected in series by GPC (manufactured by Tosoh, product name: HLC-8220GPC), tetrahydrofuran is used as a developing solvent at 0.5 mL / min. Flowed at a flow rate and measured at 40 ° C. A differential refractive index detector was used as the detector.
<Synthesis Example 1> (Synthesis of Polymer Compound 1)
In a 5 L separable flask, triscaprylylmethylammonium chloride (Tricaprylmethylmethylammonium chloride, trade name: Aliquat 336 “registered trademark”, manufactured by Aldrich) 40.18 g, the following formula:

Compound E 234.06g represented by the following formula:

172.06 g of the compound F represented by the formula:

28.5528 g of the compound G represented by the formula (1) was taken, and the gas in the flask was replaced with nitrogen. Argon bubbling 2620 g of toluene was added and argon bubbling was continued for 30 minutes with stirring. 99.1 mg of palladium acetate and 937.0 mg of tris (o-tolyl) phosphine were added, washed with 158 g of toluene, and heated to 95 ° C. After dropwise addition of 855 g of a 17.5 wt% aqueous sodium carbonate solution, the bath temperature was raised to 110 ° C. and stirred for 9.5 hours, and then 5.39 g of phenylboric acid was dissolved in 96 ml of toluene and stirred for 14 hours. 200 ml of toluene was added, the reaction solution was separated, and the organic phase was washed twice with 850 ml of 3% by weight acetic acid aqueous solution. Further, 850 ml of water and 19.89 g of sodium N, N-diethyldithiocarbamate were added and stirred for 4 hours. did. After separation, the solution was passed through a silica gel-alumina column and washed with toluene. When the obtained toluene solution was dropped into 50 L of methanol, precipitation occurred. The resulting precipitate was washed with methanol. After drying under reduced pressure, the product was dissolved in 11 L of toluene, and the resulting toluene solution was dropped into 50 L of methanol, resulting in precipitation.
The obtained precipitate was filtered and dried under reduced pressure to obtain 278.39 g of the polymer compound 1. The number average molecular weight Mn in terms of polystyrene of the polymer compound 1 was 7.7 × 10 ⁴ , and the weight average molecular weight Mw in terms of polystyrene was 3.8 × 10 ⁵ .
<Synthesis Example 2> (Synthesis of Polymer Compound 2)
In a 500 ml four-necked flask, 1.72 g of triscaprylylmethyl ammonium chloride (Triscaprylmethylmethylammonium chloride, trade name: Aliquat 336 “registered trademark”, manufactured by Aldrich), the following formula:

6.2171 g of the compound A represented by the following formula:

Compound B 0.5085 g represented by the following formula:

Compound C 6.2225g represented by the following formula:

0.5487 g of the compound D represented by the above was taken, and the gas in the flask was replaced with nitrogen. Toluene (100 ml) was added, dichlorobis (triphenylphosphine) palladium (II) (7.6 mg) and sodium carbonate aqueous solution (24 ml) were added, and the mixture was stirred under reflux for 3 hours. Thereafter, 0.40 g of phenylboric acid was added and stirred overnight. Thereafter, an aqueous sodium N, N-diethyldithiocarbamate solution was added, and the mixture was further stirred for 3 hours under reflux. The obtained reaction solution was separated, and the organic phase was washed with an aqueous acetic acid solution and water, and then dropped into methanol, resulting in precipitation. The obtained precipitate was filtered, dried under reduced pressure, dissolved in toluene, passed through a silica gel-alumina column, and washed with toluene. When the obtained toluene solution was dropped into methanol, precipitation occurred. The obtained precipitate was filtered, dried under reduced pressure, dissolved in toluene, and dropped into methanol, resulting in precipitation. The obtained precipitate was filtered and dried under reduced pressure to obtain 7.72 g of polymer compound 2 which is a conjugated polymer compound. The number average molecular weight Mn in terms of polystyrene of the polymer compound 2 was 1.2 × 10 ⁵ , and the weight average molecular weight Mw in terms of polystyrene was 2.9 × 10 ⁵ .
Example 1
(Production and evaluation of organic EL elements)
On a glass substrate on which an indium tin oxide (ITO) film corresponding to the anode (film thickness: 150 nm, formed by sputtering) is formed, a hole injection layer solution (trade name: CLEVIOS, manufactured by HC Starck Co., Ltd.) AI4083) was applied by spin coating to form a hole injection layer (film thickness: 50 nm) by drying at 200 ° C. for 10 minutes on an air hot plate.
Next, the xylene solution of polymer compound 1 was filtered through a Teflon (registered trademark) filter having a pore diameter of 0.2 μm, and this solution was applied onto the hole injection layer by spin coating to form a nitrogen atmosphere in the glove box. Below, it baked at 180 degreeC for 15 minute (s), and the positive hole transport layer (film thickness: 20 nm) was formed.
Next, a 1 wt% xylene solution of a green light emitting organic material (Lumation GP1300, manufactured by Summation) was applied onto the hole transport layer by spin coating to form a light emitting layer (film thickness: about 100 nm).
Next, a 45 wt% isopropanol dispersion (HTD-711Z, manufactured by Teika) of zinc oxide nanoparticles (particle size 20-30 nm) is diluted with 5 parts by weight of isopropanol of the dispersion to prepare a coating solution. did. This coating solution was applied onto the light emitting layer with a film thickness of 220 nm by spin coating, and dried to form a functional layer insoluble in an aqueous solvent.
Next, a conductive wire layer having a thickness of 120 nm is formed by applying a wire-like conductor dispersion liquid (ClearOhm (registered trademark) Ink-N AQ: manufactured by Cambrios Technologies Corporation) in an aqueous solvent with a spin coater and drying. Obtained. The conductive wire layer formed in an unnecessary part was peeled off with a cotton swab soaked with water to obtain a conductive wire layer having a predetermined pattern corresponding to the cathode. Then, the organic EL element was obtained by sealing with UV curable sealing agent.
A voltage was applied stepwise to the obtained organic EL element, and the current density and the luminance of EL emission at each voltage were measured. The current efficiency value was obtained from the measurement result. The maximum value of current efficiency of the obtained device was 5.85 cd / A. The EL emission was green emission with CIE chromaticity coordinates of (0.40, 0.58).
Example 2
(Production and evaluation of organic EL elements)
Instead of the wire-like conductor dispersion of the aqueous solvent of Example 1, a low-temperature sinterable silver ink (Flow Metal SW-1020 manufactured by Bando Chemical Co., Ltd.) A silver nanoparticle dispersion) was applied onto the functional layer by spin coating, and sintered at 130 ° C. for 30 minutes in a nitrogen atmosphere to form a cathode having a thickness of 700 nm. Then, the organic EL element was obtained by sealing with UV curable sealing agent.
A voltage was applied stepwise to the obtained organic EL element, and the current density and the luminance of EL emission at each voltage were measured. The current efficiency value was obtained from the measurement result. The maximum value of current efficiency of the obtained element was 0.49 cd / A. The EL emission was green emission with CIE chromaticity coordinates of (0.38, 0.59).
Example 3
(Production and evaluation of organic EL elements)
On a glass substrate on which an indium tin oxide (ITO) film corresponding to the anode (film thickness: 150 nm, formed by sputtering) is formed, a hole injection layer solution (trade name: CLEVIOS, manufactured by HC Starck Co., Ltd.) AI4083) was applied by spin coating to form a hole injection layer (film thickness: 50 nm) by drying at 200 ° C. for 10 minutes on an air hot plate.
Next, the xylene solution of polymer compound 1 was filtered through a Teflon (registered trademark) filter having a pore diameter of 0.2 μm, and this solution was applied onto the hole injection layer by spin coating to form a nitrogen atmosphere in the glove box. Below, it baked at 180 degreeC for 15 minute (s), and the positive hole transport layer (film thickness: 20 nm) was formed.
Next, a xylene solution of the polymer compound 2 was applied onto the hole transport layer by spin coating to form a light emitting layer (film thickness of about 100 nm).
Next, 1 part by weight of 45% by weight isopropanol dispersion (HTD-711Z, manufactured by Teika) of zinc oxide nanoparticles (particle size 20 to 30 nm) and 5% by weight of isopropanol in which 1% by weight of calcium bisacetylacetonate is dissolved. The coating liquid was prepared. This coating solution was applied onto the light emitting layer with a film thickness of 210 nm by spin coating, and dried to form a functional layer insoluble in an aqueous solvent.
Next, a conductive wire layer having a thickness of 120 nm is formed by applying a wire-like conductor dispersion liquid (ClearOhm (registered trademark) Ink-N AQ: manufactured by Cambrios Technologies Corporation) in an aqueous solvent with a spin coater and drying. Obtained. The conductive wire layer formed in an unnecessary part was peeled off with a cotton swab soaked with water to obtain a conductive wire layer having a predetermined pattern corresponding to the cathode. Then, the organic EL element was obtained by sealing with UV curable sealing agent.
A voltage was applied stepwise to the obtained organic EL element, and the current density and the luminance of EL emission at each voltage were measured. The current efficiency value was obtained from the measurement result. The maximum value of current efficiency of the obtained element was 0.47 cd / A. The EL emission was blue emission with CIE chromaticity coordinates of (0.15, 0.23).
Example 4
(Production and evaluation of organic EL elements)
On a glass substrate on which an indium tin oxide (ITO) film corresponding to the anode (film thickness: 150 nm, formed by sputtering) is formed, a hole injection layer solution (trade name: CLEVIOS, manufactured by HC Starck Co., Ltd.) AI4083) was applied by spin coating to form a hole injection layer (film thickness: 50 nm) by drying at 200 ° C. for 10 minutes on an air hot plate.
Next, the xylene solution of polymer compound 1 was filtered through a Teflon (registered trademark) filter having a pore diameter of 0.2 μm, and this solution was applied onto the hole injection layer by spin coating to form a nitrogen atmosphere in the glove box. Below, it baked at 180 degreeC for 15 minute (s), and the positive hole transport layer (film thickness: 20 nm) was formed.
Next, a xylene solution of the polymer compound 2 was applied onto the hole transport layer by spin coating to form a light emitting layer (film thickness of about 100 nm).
Next, 1 part by weight of 45% by weight isopropanol dispersion (HTD-711Z, manufactured by Teica) of zinc oxide nanoparticles (particle size 20-30 nm) and 5 parts by weight of methanol in which 1% by weight of cesium carbonate was dissolved Mixing was performed to prepare a coating solution. This coating solution was applied to the light emitting layer with a thickness of 290 nm by spin coating and dried to form a functional layer insoluble in an aqueous solvent.
Next, a conductive wire layer having a thickness of 120 nm is formed by applying a wire-like conductor dispersion liquid (ClearOhm (registered trademark) Ink-N AQ: manufactured by Cambrios Technologies Corporation) in an aqueous solvent with a spin coater and drying. Obtained. The conductive wire layer formed in an unnecessary part was peeled off with a cotton swab soaked with water to obtain a conductive wire layer having a predetermined pattern corresponding to the cathode. Then, the organic EL element was obtained by sealing with UV curable sealing agent.
A voltage was applied stepwise to the obtained organic EL element, and the current density and the luminance of EL emission at each voltage were measured. The current efficiency value was obtained from the measurement result. The maximum value of current efficiency of the obtained element was 1.4 cd / A. The EL emission was blue emission with CIE chromaticity coordinates of (0.15, 0.22).
Example 5
(Production and evaluation of organic EL elements)
On a glass substrate on which an indium tin oxide (ITO) film corresponding to the anode (film thickness: 150 nm, formed by sputtering) is formed, a hole injection layer solution (trade name: CLEVIOS, manufactured by HC Starck Co., Ltd.) AI4083) was applied by spin coating to form a hole injection layer (film thickness: 50 nm) by drying at 200 ° C. for 10 minutes on an air hot plate.
Next, the xylene solution of polymer compound 1 was filtered through a Teflon (registered trademark) filter having a pore diameter of 0.2 μm, and this solution was applied onto the hole injection layer by spin coating to form a nitrogen atmosphere in the glove box. Below, it baked at 180 degreeC for 15 minute (s), and the positive hole transport layer (film thickness: 20 nm) was formed.
Next, a xylene solution of the polymer compound 2 was applied onto the hole transport layer by spin coating to form a light emitting layer (film thickness of about 100 nm).
Next, 1 part by weight of 45% by weight isopropanol dispersion (HTD-711Z, manufactured by Teica) of zinc oxide nanoparticles (particle size 20-30 nm) and 5 parts by weight of isopropanol in which 1% by weight of sodium tert-butoxide is dissolved. Were mixed to prepare a coating solution. This coating solution was applied on the light emitting layer with a film thickness of 330 nm by spin coating and dried to form a functional layer insoluble in an aqueous solvent.
Next, a conductive wire layer having a thickness of 120 nm is formed by applying a wire-like conductor dispersion liquid (ClearOhm (registered trademark) Ink-N AQ: manufactured by Cambrios Technologies Corporation) in an aqueous solvent with a spin coater and drying. Obtained. The conductive wire layer formed in an unnecessary part was peeled off with a cotton swab soaked with water to obtain a conductive wire layer having a predetermined pattern corresponding to the cathode. Then, the organic EL element was obtained by sealing with UV curable sealing agent.
A voltage was applied stepwise to the obtained organic EL element, and the current density and the luminance of EL emission at each voltage were measured. The current efficiency value was obtained from the measurement result. The maximum value of current efficiency of the obtained device was 1.9 cd / A. The EL emission was blue emission with CIE chromaticity coordinates of (0.15, 0.22).
Example 6
(Production and evaluation of organic EL elements)
On a glass substrate on which an indium tin oxide (ITO) film corresponding to the anode (film thickness: 150 nm, formed by sputtering) is formed, a hole injection layer solution (trade name: CLEVIOS, manufactured by HC Starck Co., Ltd.) AI4083) was applied by spin coating to form a hole injection layer (film thickness: 50 nm) by drying at 200 ° C. for 10 minutes on an air hot plate.
Next, the xylene solution of polymer compound 1 was filtered through a Teflon (registered trademark) filter having a pore diameter of 0.2 μm, and this solution was applied onto the hole injection layer by spin coating to form a nitrogen atmosphere in the glove box. Below, it baked at 180 degreeC for 15 minute (s), and the positive hole transport layer (film thickness: 20 nm) was formed.
Next, a xylene solution of the polymer compound 2 was applied onto the hole transport layer by spin coating to form a light emitting layer (film thickness of about 100 nm).
Next, 1 part by weight of a 45% by weight isopropanol dispersion (HTD-711Z, manufactured by Teika) of zinc oxide nanoparticles (particle size: 20 to 30 nm) and 5 parts by weight of isopropanol in which 1% by weight of sodium acetylacetonate is dissolved Were mixed to prepare a coating solution. This coating solution was applied onto the light emitting layer with a film thickness of 210 nm by spin coating, and dried to form a functional layer insoluble in an aqueous solvent.
Next, a conductive wire layer having a thickness of 120 nm is formed by applying a wire-like conductor dispersion liquid (ClearOhm (registered trademark) Ink-N AQ: manufactured by Cambrios Technologies Corporation) in an aqueous solvent with a spin coater and drying. Obtained. The conductive wire layer formed in an unnecessary part was peeled off with a cotton swab soaked with water to obtain a conductive wire layer having a predetermined pattern corresponding to the cathode. Then, the organic EL element was obtained by sealing with UV curable sealing agent.
A voltage was applied stepwise to the obtained organic EL element, and the current density and the luminance of EL emission at each voltage were measured. The current efficiency value was obtained from the measurement result. The maximum value of current efficiency of the obtained device was 3.08 cd / A. The EL emission was blue emission with CIE chromaticity coordinates of (0.15, 0.23).
Example 7
(Production and evaluation of organic EL elements)
On a glass substrate on which an indium tin oxide (ITO) film corresponding to the anode (film thickness: 150 nm, formed by sputtering) is formed, a hole injection layer solution (trade name: CLEVIOS, manufactured by HC Starck Co., Ltd.) AI4083) was applied by spin coating to form a hole injection layer (film thickness: 50 nm) by drying at 200 ° C. for 10 minutes on an air hot plate.
Next, the xylene solution of polymer compound 1 was filtered through a Teflon (registered trademark) filter having a pore diameter of 0.2 μm, and this solution was applied onto the hole injection layer by spin coating to form a nitrogen atmosphere in the glove box. Below, it baked at 180 degreeC for 15 minute (s), and the positive hole transport layer (film thickness: 20 nm) was formed.
Next, a xylene solution of the polymer compound 2 was applied onto the hole transport layer by spin coating to form a light emitting layer (film thickness of about 100 nm).
Next, 1 part by weight of 45% by weight isopropanol dispersion (HTD-711Z, manufactured by Teica) of zinc oxide nanoparticles (particle size 20-30 nm) and 5 parts by weight of isopropanol in which 1% by weight of cesium acetate was dissolved Mixing was performed to prepare a coating solution. This coating solution was applied onto the light emitting layer with a film thickness of 210 nm by spin coating, and dried to form a functional layer insoluble in an aqueous solvent.
Next, a conductive wire layer having a thickness of 120 nm is formed by applying a wire-like conductor dispersion liquid (ClearOhm (registered trademark) Ink-N AQ: manufactured by Cambrios Technologies Corporation) in an aqueous solvent with a spin coater and drying. Obtained. The conductive wire layer formed in an unnecessary part was peeled off with a cotton swab soaked with water to obtain a conductive wire layer having a predetermined pattern corresponding to the cathode. Then, the organic EL element was obtained by sealing with UV curable sealing agent.
A voltage was applied stepwise to the obtained organic EL element, and the current density and the luminance of EL emission at each voltage were measured. The current efficiency value was obtained from the measurement result. The maximum value of current efficiency of the obtained device was 1.91 cd / A. The EL emission was blue emission with CIE chromaticity coordinates of (0.15, 0.22).
Example 8
(Production and evaluation of organic EL elements)
On a glass substrate on which an indium tin oxide (ITO) film corresponding to the anode (film thickness: 150 nm, formed by sputtering) is formed, a hole injection layer solution (trade name: CLEVIOS, manufactured by HC Starck Co., Ltd.) AI4083) was applied by spin coating to form a hole injection layer (film thickness: 50 nm) by drying at 200 ° C. for 10 minutes on an air hot plate.
Next, the xylene solution of polymer compound 1 was filtered through a Teflon (registered trademark) filter having a pore diameter of 0.2 μm, and this solution was applied onto the hole injection layer by spin coating to form a nitrogen atmosphere in the glove box. Below, it baked at 180 degreeC for 15 minute (s), and the positive hole transport layer (film thickness: 20 nm) was formed.
Next, a xylene solution of the polymer compound 2 was applied onto the hole transport layer by spin coating to form a light emitting layer (film thickness of about 100 nm).
Next, 1 part by weight of 45% by weight isopropanol dispersion (HTD-711Z, manufactured by Teica) of zinc oxide nanoparticles (particle size 20-30 nm) and 5 parts by weight of isopropanol in which 5% by weight of cesium acetate were dissolved Mixing was performed to prepare a coating solution. This coating solution was applied onto the light emitting layer with a film thickness of 210 nm by spin coating, and dried to form a functional layer insoluble in an aqueous solvent.
Next, a conductive wire layer having a thickness of 120 nm is formed by applying a wire-like conductor dispersion liquid (ClearOhm (registered trademark) Ink-N AQ: manufactured by Cambrios Technologies Corporation) in an aqueous solvent with a spin coater and drying. Obtained. The conductive wire layer formed in an unnecessary part was peeled off with a cotton swab soaked with water to obtain a conductive wire layer having a predetermined pattern corresponding to the cathode. Then, the organic EL element was obtained by sealing with UV curable sealing agent.
A voltage was applied stepwise to the obtained organic EL element, and the current density and the luminance of EL emission at each voltage were measured. The current efficiency value was obtained from the measurement result. The maximum value of current efficiency of the obtained device was 2.17 cd / A. The EL emission was blue emission with CIE chromaticity coordinates of (0.15, 0.22).
Example 9
(Production and evaluation of organic EL elements)
On a glass substrate on which an indium tin oxide (ITO) film corresponding to the anode (film thickness: 150 nm, formed by sputtering) is formed, a hole injection layer solution (trade name: CLEVIOS, manufactured by HC Starck Co., Ltd.) AI4083) was applied by spin coating to form a hole injection layer (film thickness: 50 nm) by drying at 200 ° C. for 10 minutes on an air hot plate.
Next, the xylene solution of polymer compound 1 was filtered through a Teflon (registered trademark) filter having a pore diameter of 0.2 μm, and this solution was applied onto the hole injection layer by spin coating to form a nitrogen atmosphere in the glove box. Below, it baked at 180 degreeC for 15 minute (s), and the positive hole transport layer (film thickness: 20 nm) was formed.
Next, a xylene solution of the polymer compound 2 was applied onto the hole transport layer by spin coating to form a light emitting layer (film thickness of about 100 nm).
Next, 1 part by weight of a 45% by weight isopropanol dispersion (HTD-711Z, manufactured by Teica) of zinc oxide nanoparticles (particle size 20 to 30 nm), 5 parts by weight of isopropanol in which 1% by weight of cesium hydroxide was dissolved, Were mixed to prepare a coating solution. This coating solution was applied onto the light emitting layer with a film thickness of 210 nm by spin coating, and dried to form a functional layer insoluble in an aqueous solvent.
Next, a conductive wire layer having a thickness of 120 nm is formed by applying a wire-like conductor dispersion liquid (ClearOhm (registered trademark) Ink-N AQ: manufactured by Cambrios Technologies Corporation) in an aqueous solvent with a spin coater and drying. Obtained. The conductive wire layer formed in an unnecessary part was peeled off with a cotton swab soaked with water to obtain a conductive wire layer having a predetermined pattern corresponding to the cathode. Then, the organic EL element was obtained by sealing with UV curable sealing agent.
A voltage was applied stepwise to the obtained organic EL element, and the current density and the luminance of EL emission at each voltage were measured. The current efficiency value was obtained from the measurement result. The maximum value of current efficiency of the obtained device was 2.37 cd / A. The EL emission was blue emission with a CIE chromaticity coordinate of (0.15, 0.21).
Comparative Example 1
(Production and evaluation of organic EL elements)
On a glass substrate on which an indium tin oxide (ITO) film corresponding to the anode (film thickness: 150 nm, formed by sputtering) is formed, a hole injection layer solution (trade name: CLEVIOS, manufactured by HC Starck Co., Ltd.) AI4083) was applied by spin coating to form a hole injection layer (film thickness: 50 nm) by drying at 200 ° C. for 10 minutes on an air hot plate.
Next, the xylene solution of polymer compound 1 was filtered through a Teflon (registered trademark) filter having a pore diameter of 0.2 μm, and this solution was applied onto the hole injection layer by spin coating to form a nitrogen atmosphere in the glove box. Below, it baked at 180 degreeC for 15 minute (s), and the positive hole transport layer (film thickness: 20 nm) was formed.
Next, a 1 wt% xylene solution of a green light emitting organic material (Lumation GP1300, manufactured by Summation) was applied onto the hole transport layer by spin coating to form a light emitting layer (film thickness: about 100 nm).
Next, a wire-like conductor dispersion liquid (ClearOhm (registered trademark) Ink-N AQ: manufactured by Cambridge Technologies Corporation) in an aqueous solvent is applied by a spin coater and dried to form a conductive wire layer having a thickness of 120 nm. Obtained. The conductive wire layer formed in an unnecessary part was peeled off with a cotton swab soaked with water to obtain a conductive wire layer having a predetermined pattern corresponding to the cathode. Then, the organic EL element was obtained by sealing with UV curable sealing agent.
A voltage was applied stepwise to the obtained organic EL element, and the current density and the luminance of EL emission at each voltage were measured. The current efficiency value was obtained from the measurement result. The maximum value of current efficiency of the obtained device was 0.33 cd / A. The EL emission was green emission with CIE chromaticity coordinates of (0.40, 0.58).
Comparative Example 2
(Production and evaluation of organic EL elements)
Instead of the wire-like conductor dispersion liquid of the aqueous solvent of Comparative Example 1, a low-temperature sinterable silver ink (Flow Metal SW-1020 manufactured by Bando Chemical Co., Ltd.) is used as an aqueous solvent containing 40% by weight of silver nanoparticles having a particle diameter of 20 to 40 nm. (Silver nanoparticle dispersion) was applied onto the light emitting layer by spin coating, but the wettability of the low-temperature sintered silver ink on the surface of the light emitting layer was poor and repelled, and a cathode coating film could not be obtained. .

The organic EL device of the present invention forms a functional layer by coating a coating solution containing a particulate electron transporting material. Therefore, when forming a cathode on the functional layer, the coating for forming a cathode is used. It is possible to prevent the functional layer from being dissolved again in the liquid.

Claims

A method for producing an organic electroluminescent device, comprising forming an anode, forming a light emitting layer, forming a functional layer by coating a coating liquid containing a particulate electron transporting material, and further forming a cathode by a coating method .
The method for producing an organic electroluminescent element according to claim 1, wherein the particulate electron transporting material is particulate zinc oxide.
The coating liquid containing the particulate electron transport material contains at least one selected from the group consisting of an alkali metal complex, an alkali metal salt, an alkaline earth metal complex, and an alkaline earth metal salt. The manufacturing method of the organic electroluminescent element of Claim 1 or 2.
4. The method for producing an organic electroluminescent element according to claim 1, wherein the cathode includes polythiophene and / or a polythiophene derivative.
5. The method for producing an organic electroluminescence element according to claim 1, wherein the cathode contains polyaniline and / or a polyaniline derivative.
5. The method of manufacturing an organic electroluminescence element according to claim 1, wherein the cathode includes a conductive substance nanoparticle, a conductive substance nanowire, or a conductive substance nanotube.
An organic electroluminescence device having a structure in which a light emitting layer, a functional layer, and a cathode are laminated in this order on an anode on a support substrate, and the functional layer is formed by applying a coating liquid containing a particulate electron transporting material. An organic electroluminescence element formed by performing the above process.
A display device comprising a reflective display and a transmissive display disposed on the reflective display,
The reflective display has a reflective display layer capable of selectively displaying the first color and the second color according to a predetermined position;
The transmissive display has an organic electroluminescent element produced by the method according to any one of claims 1 to 6 or the organic electroluminescent element according to claim 7 as a pixel light source,
The organic electroluminescence element is a display device in which an anode and a cathode are realized by electrodes exhibiting optical transparency.