JP6781606B2 - Manufacturing method of organic EL element - Google Patents

Description

The present invention relates to a method for manufacturing an organic EL device.

The organic EL (Electro Luminescence) element includes an anode, an organic EL portion including a light emitting layer, and a cathode. In addition to the light emitting layer, a predetermined layer is further provided in the organic EL unit as needed. The organic EL unit may have, for example, an electron injection layer arranged between the cathode and the light emitting layer.

The organic EL element is formed by laminating each layer on a substrate. The stacking order includes a form of stacking in order from the anode side and a form of stacking in order from the cathode side. In the present specification, the form of laminating from the anode side is referred to as "forward lamination", and the form of laminating from the cathode side is referred to as "reverse lamination". For example, Patent Document 1 describes a method for manufacturing a reverse-laminated organic EL element.

Japanese Unexamined Patent Publication No. 2005-259550

If the layer structure is the same for the forward stacking and the reverse stacking, the stacking order is only the reverse order. Therefore, it is expected that the light emission characteristics of both will be the same. However, in reality, there is a difference in the characteristics between the forward lamination and the reverse lamination.

For example, in an organic EL element in which an electron injection layer is formed by a coating method, a drive voltage may be higher in an organic EL element in reverse stacking than in forward stacking. It is presumed that this is because when the organic EL element is manufactured by reverse lamination, a step of forming an electron injection layer on the cathode by a coating method occurs, and the cathode is modified at that time.

Therefore, an object of the present invention is to provide a method for manufacturing an organic EL device which is a reverse laminated type in which a cathode is arranged on a substrate side from an anode and can realize a low driving voltage.

The method for producing an organic EL element according to the present invention includes a step of forming an electrode layer containing a metal material which becomes an n-type semiconductor by being modified on a substrate, and an organic including a light emitting layer on the electrode layer. A step of forming an EL portion and a step of forming an anode on the organic EL portion are provided, and after the step of forming the electrode layer, the electrode layer is modified to include an n-type semiconductor region. Form a cathode.

In the above method for manufacturing an organic EL element, it is possible to manufacture a reverse-stacked organic EL element provided with a cathode, an organic EL portion, and an anode in this order from the substrate side. After the step of forming the electrode layer, the cathode including the n-type semiconductor region is formed by modifying the electrode layer. As described above, since the cathode includes the n-type semiconductor region, electron injection from the cathode toward the organic EL portion is less likely to be hindered. As a result, a low drive voltage can be realized.

The step of forming the organic EL portion includes a step of forming an electron injection layer on the electrode layer and a step of forming the light emitting layer on the electron injection layer, and the electron injection layer is formed. In the step of forming, the electron injection layer may be formed by a coating method using a coating solution containing a solvent or a dispersion medium capable of modifying at least the surface portion of the electrode layer.

With this manufacturing method, it is possible to manufacture an organic EL device in which an electron injection layer is in contact with a cathode. The electron injection layer is formed by a coating method, and the coating method uses a solvent or a dispersion medium capable of modifying at least the surface portion of the electrode layer. At least the surface portion of the electrode layer can be modified by this solvent or dispersion medium. In this case, the electron injection layer can be formed by the coating method, and at least the surface portion of the electrode layer can be modified during the formation of the electron injection layer to obtain a cathode, so that the productivity of the organic EL element can be improved. Can be planned.

The metal material can be zinc, titanium or indium.

The anode may have translucency with respect to visible light. In this case, light can be output from the anode side.

In the step of forming the electrode layer in a form in which the anode has transparency to visible light, the first layer and the second layer are formed in order from the substrate side, and the material of the second layer is the metal material. The material of the first layer may be a metal material having a higher reflectance to visible light than the metal material constituting the second layer.

In this case, a cathode is formed on which a layer corresponding to the second layer and having a surface portion modified to an n-type semiconductor region is laminated on the layer corresponding to the first layer. Since the material of the first layer is composed of a metal material having a higher reflectance with respect to visible light than the material of the second layer, the light from the light emitting layer is efficiently reflected by the cathode in the organic EL element. Cheap. As a result, the luminous efficiency of the organic EL element is improved.

The material of the first layer may be a metal material having a reflectance of 70% or more with respect to visible light. An example of the material of the first layer can be aluminum or silver.

According to the present invention, it is possible to provide a method for manufacturing an organic EL element which is a reverse laminated type in which a cathode is arranged on a substrate side from an anode and can realize a low driving voltage.

FIG. 1 is a schematic diagram showing a configuration of an example of an organic EL device manufactured by the method for manufacturing an organic EL device according to an embodiment. FIG. 2 is a flowchart of an example of the method for manufacturing the organic EL element shown in FIG. FIG. 3 is a drawing for explaining a process of forming an electrode layer. FIG. 4 is a drawing for explaining a process of forming an electron injection layer. FIG. 5 is a schematic view showing a configuration of a modified example of the organic EL element shown in FIG. FIG. 6 is a flowchart of an example of the method for manufacturing the organic EL element shown in FIG. FIG. 7 is a drawing for explaining a process of forming an electrode layer. FIG. 8 is a graph showing the experimental results of the experimental element E1a used in the verification experiment 1. FIG. 9 is a graph showing the experimental results of the experimental element E1b used in the verification experiment 1. FIG. 10 is an experimental result of the verification experiment 2 and is a graph showing the measurement result of the luminance with respect to the voltage. FIG. 11 is an experimental result of the verification experiment 2 and is a graph showing the measurement result of the current density with respect to the voltage. FIG. 12 is a graph showing the experimental results of the verification experiment 3. FIG. 13 is a graph showing the experimental results of the verification experiment 4.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same elements are designated by the same reference numerals, and duplicate description will be omitted. The dimensional ratios in the drawings do not always match those described.

In the organic EL element 10 manufactured by the method for manufacturing an organic EL element of the present embodiment, the cathode 14, the organic EL portion 16, and the anode 18 are arranged in this order on the substrate 12, as schematically shown in FIG. It is constructed by stacking. Unless otherwise noted, the organic EL element 10 emits light from the anode 18 side, not from the substrate 12 side.

[substrate]
As the substrate 12, a substrate 12 that does not chemically change in the process of manufacturing the organic EL element 10 is preferably used. In the organic EL element 10 of the present embodiment, both the substrate 12 having translucency and the substrate 12 having no translucency can be used. For the substrate 12, for example, a glass plate, a polymer film, a silicon plate, a metal foil such as aluminum or copper foil, or a laminated product thereof is used. A flexible substrate or a rigid substrate is used for the substrate 12 depending on the application of the organic EL element 10. The thickness of the substrate 12 is, for example, 30 μm or more and 700 μm or less.

[cathode]
The cathode 14 includes an n-type semiconductor region 14a. For example, as shown in FIG. 1, the cathode 14 includes an n-type semiconductor region 14a at least on the surface portion (the portion on the organic EL portion 16 side). Although FIG. 1 illustrates a form in which the cathode 14 includes an n-type semiconductor region 14a and a metal region 14b, the entire cathode 14 may be an n-type semiconductor region 14a. The n-type semiconductor region 14a in the present specification preferably has an electrical resistivity (Ω · cm) of 9 × 10 ⁻⁵ Ω · cm or more and 1 × 10 ^-1 Ω · cm or less.

The cathode 14 contains a metallic material that can be modified to form an n-type semiconductor region 14a. Examples of the material (cathode material) of the cathode 14 include indium (In), zinc (Zn), tin (Sn), titanium (Ti), cadmium (Cd), gallium (Ga), copper (Cu) and the like. .. Among these, Zn, Ti or In is preferable, and Zn is more preferable. Here, reforming refers to a chemical change to a composition different from the original material due to an external factor.

The thickness of the cathode 14 is, for example, 0. It is lnm or more and 500 nm or less. This is because if it is too thin, the effect of providing the cathode 14 becomes small, and if it is too thick, the amount of light absorbed increases.

[Organic EL part]
The organic EL unit 16 is provided between the cathode 14 and the anode 18, and performs charge transfer, charge recombination, and the like according to the power (for example, voltage) applied between the anode 18 and the cathode 14. , An organic EL functional unit that contributes to the light emission of the organic EL element 10. The organic EL unit 16 includes an electron injection layer 161 and a light emitting layer 162 as functional layers. As will be described later, the organic EL unit 16 may include another functional layer.

(Electron injection layer)
The electron injection layer 161 is arranged in contact with the cathode 14. The electron injection layer 161 contains an ionic polymer.

Examples of the ionic polymer contained in the electron injection layer 161 include JP-A-2009-239279, JP-A-2012-033845, JP-A-2012-216821, JP-A-2012-216822, and JP-A. Examples include the compounds described in 2012-216815.

(Light emitting layer)
The light emitting layer 162 is a functional layer having a function of emitting light (including visible light). Usually, it is mainly composed of an organic substance that emits at least one of fluorescence and phosphorescence, or an organic substance and a dopant that assists the organic substance. Dopants are added, for example, to improve luminous efficiency and change the emission wavelength. The organic substance may be a low molecular weight compound or a high molecular weight compound. Emitting layer 162 has a number average molecular weight in terms of ^polystyrene, preferably contains a polymer compound is 10 3 to 10 ^8. The thickness of the light emitting layer 162 is, for example, about 2 nm to 200 nm.

Examples of organic substances that are luminescent materials that mainly emit at least one of fluorescence and phosphorescent light include the following pigment-based materials, metal complex-based materials, and polymer-based materials.

(Dye material)
Examples of the dye-based material include cyclopendamine derivatives, tetraphenylbutadiene derivative compounds, triphenylamine derivatives, oxaziazole derivatives, pyrazoloquinolin derivatives, distyrylbenzene derivatives, distyrylarylene derivatives, pyrrole derivatives, and thiophene ring compounds. , Pylin ring compounds, perinone derivatives, perylene derivatives, oligothiophene derivatives, oxaziazole dimers, pyrazoline dimers, quinacridone derivatives, coumarin derivatives and the like.

(Metal complex material)
Examples of the metal complex material include rare earth metals such as Tb, Eu, and Dy, or Al, Zn, Be, Ir, and Pt as the central metal, and oxadiazole, thiadiazol, phenylpyridine, phenylbenzoimidazole, and quinoline. Examples of metal complexes having a structure as a ligand include metal complexes that emit light from a triple-term excited state such as iridium complexes and platinum complexes, aluminum quinolinol complexes, benzoquinolinol berylium complexes, and benzoxazolyl zinc. Examples thereof include a complex, a benzothiazole zinc complex, an azomethylzinc complex, a porphyrin zinc complex, and a phenanthroline europium complex.

(Polymer-based material)
As the polymer-based material, a polyparaphenylene vinylene derivative, a polythiophene derivative, a polyparaphenylene derivative, a polysilane derivative, a polyacetylene derivative, a polyfluorene derivative, a polyvinylcarbazole derivative, and the above-mentioned dye-based material and metal complex-based luminescent material are polymerized. You can mention things.

Among the above-mentioned luminescent materials, examples of the material that emits blue light include dystilyl arylene derivatives, oxadiazole derivatives, and polymers thereof, polyvinylcarbazole derivatives, polyparaphenylene derivatives, and polyfluorene derivatives. Of these, polyvinylcarbazole derivatives, polyparaphenylene derivatives and polyfluorene derivatives, which are polymer materials, are preferable.

Examples of the material that emits green light include quinacridone derivatives, coumarin derivatives and polymers thereof, polyparaphenylene vinylene derivatives, polyfluorene derivatives and the like. Among them, as the material that emits green light, a polyparaphenylene vinylene derivative or a polyfluorene derivative, which is a polymer material, is preferable.

Examples of the material that emits red light include coumarin derivatives, thiophene ring compounds and polymers thereof, polyparaphenylene vinylene derivatives, polythiophene derivatives, polyfluorene derivatives and the like. Among them, as the material that emits red light, a polyparaphenylene vinylene derivative, a polythiophene derivative, a polyfluorene derivative, etc., which are polymer materials, are preferable.

(Dopant material)
Examples of the dopant material include perylene derivative, coumarin derivative, rubrene derivative, quinacridone derivative, squalium derivative, porphyrin derivative, styryl dye, tetracene derivative, pyrazolone derivative, decacyclene and phenoxazone.

The organic EL unit 16 may further have a predetermined functional layer, if necessary. For example, an electron transport layer, a hole transport layer, a hole injection layer, and the like may be provided between the cathode 14 and the anode 18.

An example of the layer structure that the organic EL element 10 can have is shown below.
(A) Cathode / electron injection layer / light emitting layer / hole injection layer / anode (b) cathode / electron injection layer / electron transport layer / light emitting layer / hole injection layer / anode (c) cathode / electron injection layer / light emission Layer / hole transport layer / hole injection layer / anode (d) cathode / electron injection layer / electron transport layer / light emitting layer / hole transport layer / hole injection layer / anode (e) cathode / electron injection layer / light emission Layer / anode (f) cathode / electron injection layer / electron transport layer / light emitting layer / anode (g) cathode / light emitting layer / anode (h) cathode / light emitting layer / hole injection layer / anode (i) cathode / light emitting layer / Hole transport layer / Hole injection layer / Anode (Here, the symbol "/" indicates that the layers sandwiching the symbol "/" are laminated adjacent to each other. The same shall apply hereinafter.) The organic of the present embodiment. The EL element 10 may have two or more light emitting layers 162.

(Hole injection layer)
Examples of the hole injection material constituting the hole injection layer include oxides such as vanadium oxide, molybdenum oxide, ruthenium oxide, and aluminum oxide, phenylamine compounds, starburst amine compounds, phthalocyanine, and amorphous carbon. Examples thereof include polyaniline and polythiophene derivatives.

The thickness of the hole injection layer is appropriately set in consideration of electrical characteristics, ease of film formation, and the like, and is, for example, 1 nm to 1 μm, preferably 2 nm to 500 nm, and more preferably 5 nm to 200 nm. is there.

(Hole transport layer)
Examples of the hole transport material constituting the hole transport layer include polyvinylcarbazole or a derivative thereof, polysilane or a derivative thereof, a polysiloxane derivative having an aromatic amine in the side chain or the main chain, a pyrazoline derivative, an arylamine derivative, and a stillben derivative. Triphenyldiamine derivative, polyaniline or its derivative, polythiophene or its derivative, polyarylamine or its derivative, polypyrrole or its derivative, poly (p-phenylene vinylene) or its derivative, or poly (2,5-thienylene vinylene) or The derivative and the like can be mentioned.

Among these, as the hole transport material, polyvinylcarbazole or its derivative, polysilane or its derivative, polysiloxane derivative having an aromatic amine compound group in the side chain or main chain, polyaniline or its derivative, polythiophene or its derivative, poly A high molecular weight hole transporting material such as arylamine or a derivative thereof, poly (p-phenylene vinylene) or a derivative thereof, or poly (2,5-thienylene vinylene) or a derivative thereof is preferable, and polyvinylcarbazole or a derivative thereof is more preferable. , Polysilane or its derivative, polysiloxane derivative having aromatic amine in the side chain or main chain. In the case of a low molecular weight hole transport material, it is preferable to disperse it in a high molecular weight binder.

The thickness of the hole transport layer is appropriately set in consideration of electrical characteristics, ease of film formation, and the like, and is, for example, 1 nm to 1 μm, preferably 2 nm to 500 nm, and more preferably 5 nm to 200 nm. Is.

(Electronic transport layer)
As the electron transport material constituting the electron transport layer, known materials can be used, and oxadiazole derivatives, anthracinodimethane or its derivatives, benzoquinone or its derivatives, naphthoquinone or its derivatives, anthraquinone or its derivatives, tetracyanoanthra. Kinodimethane or its derivatives, fluorenone derivatives, diphenyldicyanoethylene or its derivatives, diphenoquinone derivatives, or metal complexes of 8-hydroxyquinoline or its derivatives, polyquinolin or its derivatives, polyquinoxalin or its derivatives, polyfluorene or its derivatives, etc. Can be mentioned.

Among these, the electron transporting material includes oxadiazole derivative, benzoquinone or its derivative, anthraquinone or its derivative, or metal complex of 8-hydroxyquinoline or its derivative, polyquinoline or its derivative, polyquinoxalin or its derivative, polyfluorene. Alternatively, a derivative thereof is preferable, and 2- (4-biphenylyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, benzoquinone, anthraquinone, tris (8-quinolinol) aluminum, and polyquinoline are further preferable. preferable.

The thickness of the electron transport layer is appropriately set in consideration of electrical characteristics, ease of film formation, and the like, and is, for example, 1 nm to 1 μm, preferably 2 nm to 500 nm, and more preferably 5 nm to 200 nm. ..

[anode]
In the case of a configuration in which the light emitted from the light emitting layer 162 is emitted through the anode 18 as in the organic EL element 10, an electrode having translucency with respect to visible light is used for the anode 18. As the electrode having light transmittance, a thin film such as a metal oxide, a metal sulfide, or a metal having high electric conductivity can be used, and one having high light transmittance is preferably used. Specifically, thin films made of indium oxide, zinc oxide, tin oxide, indium tin oxide (ITO), indium zinc oxide (IZO), gold, platinum, silver, copper and the like are used, and among these, ITO, A thin film made of IZO or tin oxide is preferably used. As the anode 18, an organic transparent conductive film such as polyaniline or a derivative thereof, polythiophene or a derivative thereof may be used.

The thickness of the anode 18 can be appropriately selected in consideration of light transmission, electrical resistance, etc., and is, for example, 10 nm to 10 μm, preferably 20 nm to 1 μm, and more preferably 50 nm to 500 nm. ..

[Manufacturing method of organic EL element]
Next, as shown in FIG. 1, an example of a method for manufacturing the organic EL element 10 in which the organic EL unit 16 has a laminated structure of the electron injection layer 161 and the light emitting layer 162 will be described.

As shown in FIG. 2, the method for manufacturing an organic EL element includes a step S10 for forming an electrode layer, a step S12 for forming an organic EL portion, and a step S14 for forming an anode. Hereinafter, each step will be described. Hereinafter, the step S10 for forming the electrode layer, the step S12 for forming the organic EL portion, and the step S14 for forming the anode are referred to as an electrode layer forming step S10, an organic EL portion forming step S12, and an anode forming step S14, respectively.

<Electrode layer forming process>
In the electrode layer forming step S10, the electrode layer 20 is formed on the substrate 12 as shown in FIG. The material of the electrode layer 20 is a material in which the n-type semiconductor region 14a is formed by being modified. An example of the material of the electrode layer 20 is the metal material exemplified as the cathode material in the description of the cathode 14. The electrode layer 20 is formed by, for example, an inkjet printing method, a screen printing method, a vacuum vapor deposition method, a sputtering method, or the like, and among these, it is preferable to form the electrode layer 20 by a vacuum vapor deposition method or a sputtering method.

<Organic EL part forming process>
In the organic EL portion forming step S12, the organic EL portion 16 is formed on the electrode layer 20. As shown in FIG. 2, the organic EL portion forming step S12 includes a step of forming an electron injection layer (hereinafter referred to as an “electron injection layer forming step”) S12A and a step of forming a light emitting layer (hereinafter, “light emitting”). Includes (referred to as "layer formation step") S12B.

(Electron injection layer forming process)
In the electron injection layer forming step S12A, the electron injection layer 161 is formed on the electrode layer 20. In this step S12A, the electron injection layer 161 is formed by using a solvent or a dispersion medium capable of modifying at least the surface portion of the electrode layer 20 and a coating liquid (for example, ink) containing the material for the electron injection layer 161 described above. .. The solvent or dispersion medium capable of modifying at least the surface portion of the electrode layer 20 is such that only the surface portion of the electrode layer 20 can be modified, but the entire surface portion of the electrode layer 20 can be modified. It may be. Examples of the solvent or dispersion medium capable of modifying at least the surface portion of the electrode layer 20 include a polar solvent or a polar dispersion medium. Specifically, examples of the solvent or dispersion medium capable of modifying the electrode layer 20 include alcohols, ethers, esters, nitrile compounds, nitro compounds, alkyl halides, aryl halides, and thiols. Classes, sulfides, sulfoxides, thioketones, amides, carboxylic acids and the like. Among these, a solvent having a solubility of 9.3 or more is preferable, and alcohols are more preferable. Examples of the alcohols include methanol, ethanol, 2-propanol, 1-butanol, t-butyl alcohol, 1,2-ethanediol and the like.

The coating methods include spin coating method, inkjet printing method, slit coating method, micro gravure coating method, gravure coating method, bar coating method, roll coating method, wire bar coating method, spray coating method, screen printing method, and flexographic printing method. , Offset printing method, nozzle printing method and the like.

In this way, if the electron injection layer 161 is formed using a coating liquid containing a solvent or a dispersion medium capable of modifying at least the surface portion of the electrode layer 20, at least the electrode layer 20 is formed in the process of forming the electron injection layer 161. As shown in FIG. 4, the surface portion is modified to obtain the cathode 14 in which the n-type semiconductor region 14a is formed. Therefore, in the electrode layer forming step S12A, the electron injection layer 161 is formed and the n-type semiconductor region 14a is formed. Therefore, in the present embodiment, the electron injection layer forming step S12A is also a step of forming the n-type semiconductor region 14a. Since the cathode 14 including the n-type semiconductor region 14a is formed by modifying at least a part of the electrode layer 20, the electron injection layer forming step S12A can be a part of the step of forming the cathode 14. .. At this time, the unmodified portion of the electrode layer 20 becomes the metal region 14b. In the electron injection layer forming step S12A, when the entire electrode layer 20 is modified, the cathode 14 having only the n-type semiconductor region 14a without the metal region 14b is formed.

FIG. 4 shows a form in which the n-type semiconductor region 14a is formed on the surface portion of the electrode layer 20 shown in FIG. That is, the cathode 14 including the metal region 14b and the n-type semiconductor region 14a is shown in the figure.

In the present specification, the "electrode layer" means a layer corresponding to a cathode (a layer to be a cathode) in the description of the method for manufacturing an organic EL element and before being modified. The "cathode" is a component included in an organic EL device manufactured by a method for manufacturing an organic EL device, and means a component formed by modifying at least a part of an electrode layer. ..

(Light emitting layer forming process)
In the light emitting layer forming step S12B, the light emitting layer 162 is formed on the electron injection layer 161. The light emitting layer 162 is formed by, for example, a coating method, a vacuum vapor deposition method, a sputtering method, or the like, and is preferably formed by a coating method from the viewpoint of simplicity of the process. Examples of the coating method include the coating method exemplified in the above-mentioned electron injection layer forming step S12A.

When the light emitting layer 162 is formed by a coating method, it is preferable to form the light emitting layer 162 by using a coating liquid (for example, ink) that is difficult to dissolve the electron injection layer 161.

Such a coating liquid contains a material to be the light emitting layer 162 and a solvent or a dispersion medium. For example, when the electron injection layer 161 is composed of a material that dissolves in a polar solvent such as alcohols, it is preferable to use a non-polar solvent or a non-polar dispersion medium in which the electron injection layer 161 is difficult to dissolve, such a solvent. Alternatively, as the dispersion medium, for example, a chlorine-based solvent such as chloroform, methylene chloride, dichloroethane, an ether-based solvent such as tetrahydrofuran, an aromatic hydrocarbon-based solvent such as toluene and xylene, a ketone solvent such as acetone and methyl ethyl ketone, and ethyl acetate. , Ester-based solvents such as butyl acetate and ethyl cell solve acetate, and aromatic hydrocarbon-based solvents are preferable.

(Anode forming process)
In the anode forming step S14, the anode 18 is formed on the light emitting layer 162. The anode 18 is subjected to, for example, a spin coating method, an inkjet coating method, a screen printing method, a flexographic printing method, an offset flat plate printing method, a spray coating method, a nozzle printing method, a vacuum deposition method, a sputtering method, an ion plating method, a plating method, or the like. It is formed.

The method for manufacturing the organic EL element is a manufacturing method when the organic EL unit 16 has a laminated structure composed of an electron injection layer 161 and a light emitting layer 162. As described above, the organic EL unit 16 may have a layer other than the electron injection layer 161 and the light emitting layer 162 (for example, an electron transport layer, a hole transport layer, a hole injection layer, etc.). In the form in which the organic EL unit 16 includes layers other than the electron injection layer 161 and the light emitting layer 162, the corresponding layers may be formed in order from the electrode layer 20 side. The layers other than the electron injection layer 161 and the light emitting layer 162 can be formed by a coating method, a vacuum vapor deposition method, a sputtering method, an ion plating method, or the like.

The organic EL element 10 manufactured by the manufacturing method shown in the flowchart of FIG. 2 is a reverse-stacked organic EL element 10 in which the cathode 14 is located on the substrate 12 side with respect to the anode 18. In the above manufacturing method, a metal material that becomes an n-type semiconductor by being modified is used as the material of the electrode layer 20, and in the step of forming the electron injection layer 161 on the electrode layer 20, at least the electrode layer 20 is formed. The surface portion is modified to form the cathode 14 including the n-type semiconductor region 14a. Therefore, it is possible to realize a reverse-stacked organic EL element 10 that can be driven with a low drive voltage.

This point will be described in comparison with the case where aluminum, which is a material that does not form an n-type semiconductor even if modified, is used as the cathode material in contact with the organic EL portion 16.

Since aluminum has a high reflectance of visible light, it is often used as a cathode material when light is emitted from the anode 18 side in the field of the organic EL element 10. However, aluminum is easily modified by exposure to a polar solvent to form an insulating region. Therefore, when the aluminum is used as a cathode material in contact with the organic EL portion in the reverse laminated type organic EL element, the aluminum is modified in the manufacturing process and the organic EL portion is in contact with the insulating region. As a result, the electron injection property from the cathode to the light emitting layer is lowered, and the driving voltage of the organic EL element is increased.

On the other hand, in the method for manufacturing an organic EL device of the present embodiment, a metal material that is modified to become an n-type semiconductor is used as the material of the electrode layer 20, and the organic EL portion 16 is being formed (FIG. 1). In the device configuration illustrated in (1), at least the surface portion of the electrode layer 20 is modified to form the n-type semiconductor region 14a during the formation of the electron injection layer 161). Therefore, in the manufactured organic EL element 10, the organic EL unit 16 (electron injection layer 161 in the element configuration illustrated in FIG. 1) is in contact with the n-type semiconductor region 14a. Therefore, in the method for manufacturing an organic EL element of the present embodiment, it is possible to manufacture the organic EL element 10 capable of realizing a low drive voltage.

Since a metal material that becomes an n-type semiconductor by modification is used as the material of the electrode layer 20, the layer of the organic EL portion 16 in contact with the electrode layer 20 can be formed by a coating method as illustrated. .. For example, in the configuration shown in FIG. 1, an electron injection layer 161 can be formed on the electrode layer 20 by a coating method. Further, a light emitting layer 162 can also be formed on the electron injection layer 161 by a coating method. Since the coating method can be carried out while transporting the substrate 12, for example, it is easy to improve the productivity of the reverse-laminated organic EL element 10. Further, by adopting the coating method, it is possible to apply the roll-to-roll method which is advantageous for improving the productivity of the organic EL element 10.

When the layer (for example, the electron injection layer 161) to be formed directly on the electrode layer 20 is formed by the coating method, at least the surface portion of the electrode layer 20 can be modified by using a solvent or a dispersion medium during the layer formation. At least the surface portion of the electrode layer 20 can be modified to form the n-type semiconductor region 14a. In this case, since the step of forming the layer directly formed on the electrode layer 20 also serves as the step of modifying the electrode layer 20, high productivity can be realized.

(Modification example)
FIG. 5 is a schematic view of the organic EL element 10A which is a modification of the organic EL element 10 shown in FIG. The organic EL element 10A differs from the configuration of the organic EL element 10 in that it has a cathode 22 having a first cathode 221 and a second cathode 222 instead of the cathode 14. The configuration of the organic EL element 10 other than the above differences is the same as that of the organic EL element 10. Therefore, a modified example will be described focusing on the differences.

The first cathode 221 contains a metal material that becomes an n-type semiconductor by being modified, similarly to the cathode 14 included in the organic EL element 10. The example of the metal material for the first cathode 221 is the same as the metal material exemplified for the cathode 14. The first cathode 221 includes an n-type semiconductor region 221a on its surface portion (portion on the organic EL portion 16 side). An example of the thickness of the first cathode 221 is 0.1 nm to 200 nm. FIG. 5 illustrates a form in which the first cathode 221 includes an n-type semiconductor region 221a and a metal region 221b, but the entire first cathode 221 is an n-type semiconductor region 221a as in the case of the cathode 14. You may.

The second cathode 222 is arranged between the substrate 12 and the first cathode 221. The thickness of the second cathode 222 is preferably, for example, 0.1 nm to 300 nm. The second cathode 222 has a higher reflectance than the first cathode 221 with respect to visible light.

Examples of the material of the second cathode 222 include aluminum (Al), silver (Ag), gold (Au), and chromium (Cr), or alloys containing at least two of these metals. The second cathode 222 is preferably composed of Al or Ag among the exemplified metals.

The organic EL element 10A is different in that it includes an electrode layer forming step (step of forming the electrode layer) S20 instead of the electrode layer forming step S10 shown in FIG. 2, as shown in the flowchart shown in FIG. Other than that, it is manufactured by the same manufacturing method as in the case of the organic EL element 10. Therefore, as a method for manufacturing the organic EL element 10A, the electrode layer forming step S20, which is mainly the above-mentioned difference, will be described.

The electrode layer forming step S20 is a step of forming a lower layer (first layer) on the substrate 12 (hereinafter referred to as a “lower layer forming step”) S20A and forming an upper layer (second layer) on the lower layer. The step (hereinafter, referred to as “upper layer forming step”) S20B is included. As a result, in the electrode layer forming step S20, as shown in FIG. 7, the electrode layer 24 having the lower layer 241 and the upper layer 242 is formed.

The electrode layer 24 is a two-layer structure electrode layer that becomes a cathode 22 by modifying at least a part (for example, a surface portion) of the upper layer 242. Specifically, the upper layer 242 is a layer that should become the first cathode 221 by modifying at least a part (for example, a surface portion) of the upper layer 242. The lower layer 241 is a layer corresponding to the second cathode 222 in the description of the method for manufacturing the organic EL element. The lower layer 241 is not modified. That is, in the description of the method for manufacturing the organic EL element, the second cathode 222 is conveniently referred to as the lower layer 241.

In the lower layer forming step S20A, the lower layer 241 as the second cathode 222 is formed on the substrate 12. The lower layer 241 can be formed in the same manner as when the electrode layer 20 is formed, except that the material for the second cathode 222 is used. In order to realize the reflectance relationship between the first cathode 221 and the second cathode 222 described above, the material for the lower layer 241 has a higher reflectance for visible light than the material for the upper layer 242. The reflectance for the lower layer 241 is, for example, 70% or more, more preferably 90% or more with respect to visible light. In the upper layer forming step S20B, the upper layer 242 to be the first cathode 221 is formed on the lower layer 241. The upper layer 242 can form the upper layer 242 in the same manner as in the case of forming the lower layer 241 except that the material for the second cathode 222 is used. Since the material for the second cathode 222 can be the same as the material of the electrode layer 20, the upper layer forming step S20B can be the same as the electrode layer forming step S10.

After performing the electrode layer forming step S20, the organic EL element 10A is manufactured by carrying out the organic EL portion forming step S12 and the anode forming step S14 in the same manner as in the case of the organic EL element 10.

In the production of the organic EL element 10A, an upper layer 242 containing a metal material that is modified to become an n-type semiconductor is configured. Therefore, in the organic EL portion forming step S12, if the electron injection layer 161 is formed on the upper layer 242 in the same manner as in the case of the organic EL element 10, at least the surface portion of the upper layer 242 is modified, and n The first cathode 221 including the type semiconductor region 14a is formed. Therefore, in the method for manufacturing the organic EL element 10A, the electrode layer forming step S12A includes a modification step of the electrode layer 24 (more specifically, the upper layer 242).

In the organic EL element 10A manufactured by the above manufacturing method, the first cathode 221 of the cathode 22 in contact with the organic EL portion 16 includes an n-type semiconductor region 14a. Therefore, the organic EL element 10A and its manufacturing method have at least the same effects as those of the organic EL element 10 and its manufacturing method.

In the method for manufacturing the organic EL element 10A, after the lower layer 241 as the second cathode 222 is formed, the upper layer 242 to be the first cathode 221 is formed, and the material for the lower layer 241 is for the upper layer 242. It has a higher reflectance to visible light than the material of. Therefore, in the manufacturing method of this modification, the organic EL element 10A having the cathode 22 in which the first cathode 221 is laminated on the second cathode 222 having a reflectance higher than that of the first cathode 221 is manufactured. Therefore, the light emitted from the light emitting layer 162 is easily reflected by the cathode 22. As a result, the luminous efficiency of the organic EL element 10A that outputs light from the anode 18 side is improved. That is, the method for manufacturing the organic EL element described in this modification can manufacture the organic EL element 10A in which the luminous efficiency is improved while realizing a low drive voltage.

Hereinafter, the verification experiment of the action and effect of the organic EL element described in the above-described embodiment and modification will be described.

[Verification experiment 1]
In verification experiment 1, it was verified that the electron injection characteristics are improved by using a metal material that is modified to become an n-type semiconductor as a cathode material. In this verification experiment 1, an experimental element having the following element configuration (hereinafter referred to as an experimental element E1) was used.
Substrate / lower electrode / electron injection layer / light emitting layer / electron injection layer / upper electrode

As the experimental element E1 having the above configuration, an element using Zn as the material for the lower electrode (hereinafter referred to as "experimental element E1a") and an element using Al as the material for the lower electrode (hereinafter, "experiment"). The elements (referred to as "elements E1b") were manufactured.

(Manufacturing method of experimental element E1a)
For the experimental element E1a, a 0.7 mm thick glass plate was prepared as a substrate. Further, 2 mg of the ionic polymer was mixed with 1 ml of methanol to prepare a coating liquid containing the ionic polymer (hereinafter referred to as “coating liquid α”). Further, the polymer light emitting material P1 and xylene were mixed to prepare a composition C for forming a light emitting layer containing 1.3% by weight of the polymer light emitting material P1.

Next, using a load-lock type sputtering device, a thin film (Zn film) having a thickness of 50 nm and made of Zn was formed on the substrate (glass plate) as a lower electrode. A coating film is obtained by spin-coating the coating liquid α containing the ionic polymer on the Zn film in a nitrogen atmosphere, and the coating film is heated and dried at 130 ° C. for 10 minutes in a nitrogen atmosphere. An electron-injected layer having a thickness of 30 nm was obtained.

On the electron injection layer obtained above, the light emitting layer forming composition C was applied by a spin coating method in a nitrogen atmosphere to obtain a coating film having a thickness of 80 nm. The substrate on which the coating film was provided was heated at 190 ° C. for 60 minutes in a nitrogen atmosphere to evaporate the solvent and then naturally cooled to room temperature to obtain a substrate on which a light emitting layer was formed.

A coating film was obtained by spin-coating a coating liquid α containing the ionic polymer on the light emitting layer of the substrate on which the light emitting layer was formed in a nitrogen atmosphere, and the coating film was applied under a nitrogen atmosphere. The mixture was heated and dried at 130 ° C. for 10 minutes to obtain an electron-injected layer having a thickness of 30 nm. A thin film (Al film) having a thickness of 80 nm and made of Al was formed on the electron injection layer as an upper electrode by a vacuum vapor deposition method to obtain an experimental element E1a.

As can be understood from the above production method, a coating liquid containing methanol, which is a polar solvent, is used to form the electron injection layer. Therefore, in the manufacturing process, when the electron injection layer is formed on the Zn film, the surface portion of the Zn film is modified, and an n-type semiconductor region is formed on the surface portion of the Zn film. On the other hand, since the upper electrode is formed by the vacuum vapor deposition method, the electron injection layer side of the upper electrode is not modified.

(Manufacturing method of experimental element E1b)
The experimental element E1b was manufactured by the same method as the method for manufacturing the experimental element E1a, except that the material of the lower electrode was changed to Al in the method for manufacturing the experimental element E1a. Even in the experimental element E1b, a coating liquid containing methanol as a polar solvent is used for forming the electron injection layer. Therefore, in the manufacturing process, when the electron injection layer is formed on the thin film (Al film) made of Al of the lower electrode having a thickness of 50 nm, the surface portion of the Al film of the lower electrode is modified and the Al of the lower electrode is formed. An insulating region is formed on the surface of the film.

(Electron injection experiment)
For the case where a voltage from -3V to + 10V is applied between the lower electrode and the upper electrode of the experimental element E1a (first measurement) and the case where a voltage is applied from + 3V to -10V (second measurement). Then, the state of electron injection into the experimental element E1a was evaluated based on the current flowing through the experimental element E1a. The experimental results were as shown in FIG. The horizontal axis of FIG. 8 shows the voltage (V), and the vertical axis shows the current (A).

In FIG. 8, the white square mark indicates the current value when a voltage is applied from -3V to + 10V between the lower electrode and the upper electrode as the first measurement, and the white diamond mark is the second measurement. As a measurement, the current value when a voltage is applied from + 3V to -10V between the lower electrode and the upper electrode is shown. In FIG. 8, the electron injection property from the lower electrode is shown from -3V to 0V in the first measurement and from 0V to -10V in the second measurement, and from 0V to + 10V in the first measurement. From + 3V to 0V in the second measurement, the electron injection property from the upper electrode is shown.

Similarly, when a voltage is applied from -5V to + 10V between the lower electrode and the upper electrode of the experimental element E1b (first measurement) and when a voltage is applied from + 5V to -10V (second measurement). On the other hand, the state of electron injection into the experimental element E1b was evaluated based on the current flowing through the experimental element E1b. The experimental results were as shown in FIG. The horizontal axis of FIG. 9 shows the voltage (V), and the vertical axis shows the current (A).

In FIG. 9, the white square mark indicates the current value when a voltage of −5 V to + 10 V is applied between the lower electrode and the upper electrode as the first measurement. The white diamond mark indicates the current value when a voltage from + 5V to -10V is applied between the lower electrode and the upper electrode as the second measurement. Similar to the case of FIG. 8, in FIG. 9, the electron injection property from the lower electrode is shown from -5V to 0V in the first measurement and from 0V to -10V in the second measurement, and the first measurement. From 0V to + 10V in the measurement of No. 1 and from + 5V to 0V in the second measurement, the electron injection property from the upper electrode is shown.

As shown in FIG. 8, in the experimental element E1a using Zn as the material for the lower electrode, the electron injection property from the lower electrode and the electron injection property from the upper electrode made of Al are almost the same. confirmed. On the other hand, as shown in FIG. 9, in the experimental element E1b using Al as the material for the lower electrode, the electron injection property from the lower electrode is lower than the electron injection property from the upper electrode made of Al. It was confirmed that It is considered that the result of the experimental element E1b is that an insulating region is formed on the surface portion of the lower electrode.

Therefore, by using Zn, which is modified to be an n-type semiconductor, as the material for the lower electrode, the same degree as electron injection from the upper electrode (Al film) where the surface portion on the electron injection layer side is not modified. Electron injection can be realized from the lower electrode side. That is, it was verified that the electron injection property could be improved by using a metal material modified into an n-type semiconductor as the cathode material in contact with the organic EL portion.

[Verification experiment 2]
In the verification experiment 2, the effect of manufacturing an organic EL device and using a metal material modified to become an n-type semiconductor as a cathode material was verified. In this verification experiment 2, an experimental element having the following element configuration (hereinafter referred to as an experimental element E2) was used. As can be understood from the configuration below, the experimental element E2 is an organic EL element.
Substrate / Cathode / Electron injection layer / Light emitting layer / Hole transport layer / Hole injection layer / Anode

As the experimental element E2 having the above configuration, an element using Zn as the cathode material (hereinafter referred to as the experimental element E2a) and an element using Al as the cathode material (hereinafter referred to as the experimental element E2b) are manufactured. did.

(Manufacturing method of experimental element E2a)
For the production of the experimental element E2a, a 0.7 mm thick glass plate was prepared as a substrate as in the case of the experimental element E1a. Further, as a coating liquid for forming the electron injection layer, a coating liquid α was prepared as in the case of the experimental element E1a. Further, as the light emitting layer forming composition for forming the light emitting layer, the light emitting layer forming composition C was prepared as in the case of the experimental element E1a.

In the method for producing the experimental device E2a, in order to form the hole transport layer, the polymer compound P2 was dissolved in xylene at a concentration of 0.6% by weight, and a xylene solution containing the polymer compound P2 was prepared. Further, in order to form the hole injection layer, the polymer compound P3 was dissolved in a solvent to prepare a suspension of the polymer compound P3.

Next, a Zn film having a thickness of 50 nm was formed on the substrate (glass substrate) using a load-lock sputtering apparatus. A coating film was obtained by spin-coating the coating liquid α containing the ionic polymer on the Zn film in a nitrogen atmosphere, and the coating film was heated and dried at 130 ° C. for 10 minutes to make it thicker. An electron injection layer having a diameter of 10 nm was obtained.

On the electron injection layer obtained above, the light emitting layer forming composition C was applied by a spin coating method in a nitrogen atmosphere to obtain a coating film having a thickness of 80 nm. The substrate on which the coating film was provided was heated at 190 ° C. for 60 minutes in a nitrogen atmosphere to evaporate the solvent and then naturally cooled to room temperature to obtain a substrate on which a light emitting layer was formed.

A xylene solution containing the polymer compound P2 is applied onto the light emitting layer by a spin coating method in the air, and the coating film is dried by heating at 180 ° C. for 60 minutes in a nitrogen atmosphere to dry holes having a thickness of 20 nm. Obtained a transport layer.

A suspension of the polymer compound P3 is applied onto the hole transport layer by a spin coating method in the air, and heated at 170 ° C. for 15 minutes in a nitrogen atmosphere to obtain a hole injection layer having a thickness of 60 nm. It was.

A film (Au film) made of Au having a thickness of 20 nm was formed on the hole injection layer as an anode by a vacuum vapor deposition method to obtain an experimental element E2a having a light emitting portion having a size of 2 mm × 2 mm.

As can be understood from the above production method, a coating liquid containing methanol, which is a polar solvent, is used to form the electron injection layer. Therefore, in the manufacturing process, when the electron injection layer is formed on the Zn film, the surface portion of the Zn film is modified, so that a cathode having an n-type semiconducting region is formed on the surface portion.

(Manufacturing method of experimental element E2b)
The experimental element E2b was produced by the same method as the method for producing the experimental element E2a, except that the cathode material was changed to Al in the method for producing the experimental element E2a. Even in the experimental element E2b, a coating liquid containing methanol as a polar solvent is used for forming the electron injection layer. Therefore, in the manufacturing process, when the electron injection layer is formed on the Al film, the surface portion of the Al film is modified, so that a cathode having an insulating region is formed on the surface portion.

(Light emission test)
While changing the voltage applied between the cathode and the anode of each of the experimental element E2a and the experimental element E2b, the experimental element E2a and the experimental element E2b were made to emit light, and the brightness and the current density were measured. The brightness was measured by measuring the light output from the anode side using a luminance meter, and the current density was calculated from the current flowing through the experimental element E2a and the experimental element E2b and the area of the light emitting portion. The brightness measurement results are as shown in FIG. 10, and the current density measurement results are as shown in FIG. In FIG. 10, the horizontal axis represents voltage (V) and the vertical axis represents luminance (cd / m ² ). In FIG. 6, the horizontal axis represents the voltage (V) and the vertical axis represents the current density (mA / cm ² ).

As shown in FIG. 10, at the same drive voltage, the experimental element E2a was able to realize higher brightness than the experimental element E2b. As shown in FIG. 11, at the same current density, the experimental element E2a was able to realize a lower drive voltage than the experimental element E2b. For example, when the current density is 80 mA / cm ² , the drive voltage of the experimental element E2a is about 8 V, and the drive voltage of the experimental element E2b is about 10 V. That is, when the current density was 80 mA / cm ² , the drive voltage of the experimental element E2a was about 2 V lower than that of the experimental element E2b.

That is, by using a metal material (Zn in verification experiment 2) that is modified to form an n-type semiconductor as the cathode material, a metal material that is modified to form an insulating region (Al in verification experiment 2) is used. It was verified that the drive voltage of the organic EL element can be lowered as compared with the case where the organic EL element was used.

[Verification experiment 3]
An experimental element E3a in which a Zn film having a thickness of 50 nm was formed on this substrate was manufactured by using a load-lock sputtering apparatus using a glass plate having a thickness of 0.7 mm as a substrate. Similarly, a 0.7 mm thick glass plate is used as the substrate, and a load lock type sputtering device is used to form an Al film having a thickness of 50 nm on the substrate, and then a Zn film having a thickness of 2 nm is formed on the Al film. By doing so, the experimental element E3b was manufactured. In the production of the experimental element E3b, the thickness of the Zn film was changed to 5 nm, 10 nm, 15 nm, and 25 nm, but the experimental elements E3c, E3d, E3e, and E3f were manufactured in the same manner as the experimental element E3b. Manufactured.

The reflectances of the experimental elements E3a to E3f when light was incident from the Zn film side were measured using an optical thin film measuring system (Film Tek 3000) manufactured by Scientific Computing International. The experimental results were as shown in FIG. As shown in FIG. 12, it was verified that the laminated structure of the Al film and the Zn film showed higher reflectance than the experimental element E3a in which the Zn film was formed of a single layer on the substrate.

[Verification experiment 4]
In the verification experiment 4, the action and effect of the organic EL element when the cathode has a laminated structure of the second cathode and the first cathode and the second cathode has a higher reflectance with respect to visible light than the first cathode was verified.

In the verification experiment 4, an experimental element (hereinafter referred to as an experimental element E4), which is an organic EL element having the following element configuration, was used.
Substrate / Cathode / Electron injection layer / Light emitting layer / Hole transport layer / Hole injection layer / Anode

In the verification experiment 4, an experimental element (hereinafter referred to as an experimental element E5), which is an organic EL element having the following element configuration, was also used.
Substrate / 2nd cathode / 1st cathode / Electron injection layer / Light emitting layer / Hole transport layer / Hole injection layer / Anode

As the experimental element E5 having the above configuration, elements having the thickness of the first cathode of 2 nm, 5 nm, 10 nm, and 15 nm (hereinafter referred to as experimental elements E5a, E5b, E5c, E5d) were manufactured.

(Manufacturing method of experimental element E4)
The experimental device E4 was manufactured in the same manner as the experimental device E2a except that the thickness of the light emitting layer was changed to 70 nm and the thickness of the hole injection layer was changed to 65 nm. Therefore, in the manufacturing process, when the electron injection layer is formed on the Zn film, the surface portion of the Zn film is modified, and an n-type semiconductor region is formed on the surface portion of the Zn film.

(Manufacturing method of experimental element E5a)
For the production of the experimental element E5a, a glass plate having a thickness of 0.7 mm was prepared as a substrate as in the case of the experimental element E1a. Further, as a coating liquid for forming the electron injection layer, a coating liquid α was prepared as in the case of the experimental element E1a. Further, as the light emitting layer forming composition for forming the light emitting layer, the light emitting layer forming composition C was prepared as in the case of the experimental element E1a.

In the method for producing the experimental element E5a, as in the case of the experimental element E2a, the polymer compound P2 is dissolved in xylene at a concentration of 0.6% by weight in order to form a hole transport layer, and the polymer compound is formed. A xylene solution containing P2 was prepared. Further, in order to form the hole injection layer, a suspension of the polymer compound P3 was prepared as in the case of the experimental device E2a.

Next, using a load-lock type sputtering device, an Al film having a thickness of 50 nm is formed on the substrate (glass substrate) as a second cathode, and then a Zn film having a thickness of 2 nm is formed on the Al film. did. After that, the experimental element E5a was obtained in the same manner as in the method for manufacturing the experimental element E4. In the manufacturing process of the experimental element 5a, when the electron injection layer is formed on the Zn film, the surface portion of the Zn film is modified, so that a cathode having an n-type semiconductor region is formed on the surface portion.

(Manufacturing method of experimental elements E5b to E5d)
The experimental elements E5b to E5d are the same as the manufacturing method of the experimental element E5a except that the Zn film formed on the Al film having a thickness of 50 nm, which is the second cathode, is 5 nm, 10 nm, and 15 nm. Manufactured. Therefore, in the manufacturing process of each of the experimental elements E5b to E5d, when the electron injection layer is formed on the Zn film, the surface portion of the Zn film is modified, so that the cathode having the n-type semiconductor region on the surface portion is formed. It is formed.

(Light emission test)
The experimental element E4 and the experimental element E5a to 5d are made to emit light while changing the voltage applied between the cathode and the anode of each of the experimental element E4 and the experimental element E5a to 5d, and the experimental element E4 and the experimental element E5a to 5d are used for the experiment. The light emission efficiency of each of the elements E5a to 5d was calculated. Specifically, the brightness and the current density were obtained in the same manner as in the verification experiment 2, and the luminous efficiency was calculated based on them. The experimental results are as shown in FIG. In FIG. 13, the horizontal axis represents the voltage (V) and the vertical axis represents the luminous efficiency (cd / A).

As shown in FIG. 13, the experimental elements E5a to E5d laminated with Al have higher luminous efficiency than the experimental element E4 using only Zn as the cathode material. It is considered that this is because more light is reflected by the second cathode made of Al. Therefore, as in the organic EL element 10A shown in FIG. 5, by forming the cathode 22 having a laminated structure of the second cathode 222 having a reflectance higher than that of the first cathode 221 and the first cathode 221, the driving force is low. It is possible to manufacture an organic EL element capable of improving light emission efficiency while realizing a voltage.

The various embodiments and examples of the present invention have been described above. However, the present invention is not limited to the various embodiments and examples described above, and various modifications can be made without departing from the spirit of the present invention.

In the method for manufacturing the organic EL element illustrated in FIGS. 2 and 6, the electrode layer is modified by using a solvent or a dispersion medium when the organic EL portion has a layer in contact with the electrode layer and is formed by the coating method. Although the quality has been implemented, the modification method is not particularly limited as long as the electrode layer can be modified.

The modification of the electrode layer may be carried out after the step of forming the electrode layer, may be carried out during the step of forming the organic EL portion, or may be carried out before forming the organic EL portion. ..

The organic EL element may be in the form of emitting light from the substrate side as long as the cathode has translucency and is composed of a material that is modified to become an n-type semiconductor.

10, 10A ... organic EL element, 12 ... substrate, 14 ... cathode, 14a ... n-type semiconductor region, 16 ... organic EL part, 161 ... electron injection layer, 162 ... light emitting layer, 18 ... anode, 20 ... electrode layer, 22 ... Cathode, 24 ... Electrode layer, 241 ... Lower layer (first layer), 242 ... Upper layer (second layer).

Claims (6)

A process of forming an electrode layer containing a metal material that becomes an n-type semiconductor by being modified on a substrate, and
A step of forming an organic EL portion including a light emitting layer on the electrode layer,
The step of forming an anode on the organic EL part and
With
After the step of forming the electrode layer, by modifying the electrode layer, to form a cathode comprising an n-type semiconductor region,
The step of forming the organic EL portion is
A step of forming an electron injection layer on the electrode layer and
The step of forming the light emitting layer on the electron injection layer and
Have,
In the step of forming the electron injection layer, the electron injection layer is formed by a coating method using a coating solution containing a solvent or a dispersion medium capable of modifying at least the surface portion of the electrode layer.
A method for manufacturing an organic EL element. The metal material is zinc, titanium or indium.
The method for manufacturing an organic EL element according to claim 1 . The anode is translucent with respect to visible light.
The method for manufacturing an organic EL element according to claim 1 or 2 . In the step of forming the electrode layer, the first layer and the second layer are formed in order from the substrate side.
The material of the second layer is the metal material.
The material of the first layer is a metal material having a higher reflectance to visible light than the metal material constituting the second layer.
The method for manufacturing an organic EL element according to claim 3 . The material of the first layer is a metal material having a reflectance of 70% or more with respect to visible light.
The method for manufacturing an organic EL element according to claim 4 . The material of the first layer is aluminum or silver.
The method for manufacturing an organic EL element according to claim 5 .

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