JP5036680B2 - Method for manufacturing organic electroluminescence device - Google Patents

Description

  The present invention relates to a method for manufacturing an organic electroluminescent element, an organic electroluminescent element obtained by the method for manufacturing the organic electroluminescent element, an illumination device using the organic electroluminescent element, a planar light source, and a display device.

  An organic electroluminescence element (hereinafter, sometimes referred to as an organic EL element) includes a pair of electrodes composed of an anode and a cathode, and an organic light emitting layer provided between the electrodes. When a voltage is applied to the organic EL element, holes and electrons are injected from each electrode, and light is emitted by recombining the injected holes and electrons in the organic light emitting layer. An organic EL element can be driven at a lower voltage than an inorganic EL element and has high luminance. Therefore, the organic EL element has been studied as one of light-emitting elements used in a display device or a lighting device.

  Usually, a display device using organic EL elements uses a display panel in which a large number of organic EL elements each functioning as one pixel are arranged in a matrix. In such a display panel, in order to form a large number of organic EL elements at predetermined positions on the substrate, the anode is formed in a stripe-like (vertical stripe or horizontal stripe) pattern, and a grid-like partition is formed on the anode. It is formed. A region surrounded by the grid-like partition corresponds to a pixel region, and a light emitting layer or the like is selectively formed in the pixel region, whereby a large number of organic EL elements are formed at predetermined positions on the substrate. The light emitting layer is formed by supplying an organic light emitting ink containing a material for forming the light emitting layer to a region surrounded by the partition walls, and further drying the ink.

  In the conventional technology, an organic luminescent ink containing an organic luminescent material and a solvent is supplied into each partition wall using a relief printing plate having a plurality of convex portions arranged corresponding to the arrangement of the pixel regions, and organic A light emitting layer is formed (see, for example, Patent Document 1).

  As described in Patent Document 1, a method of supplying various inks to each pixel region using a relief printing method is a method suitable for efficiently producing an organic EL element. According to the results, it was found that there are problems to be solved as follows.

  When supplying organic light-emitting ink to the pixel area defined by the partition using a relief printing plate, it is necessary to accurately align the plurality of projections provided on the relief printing plate and the plurality of pixel areas, respectively. Therefore, the tolerance for positional deviation is small, the positional accuracy in the plate cylinder direction of the relief printing plate, the positional accuracy in the circumferential direction, and the angular accuracy in the feeding direction of the substrate are strict, making it difficult to manufacture efficiently.

  In addition, a predetermined layer (such as an electron injection layer and a hole injection layer) different from the light emitting layer may be provided between the anode and the cathode for the purpose of improving the device life and the light emission characteristics. Yes (see, for example, Patent Document 2). For example, there is an organic EL element in which an inorganic oxide layer such as molybdenum oxide is provided between a light emitting layer and an anode.

  When forming the light emitting layer with the above-described relief printing plate, the light emitting layer is formed by a coating method after the molybdenum oxide layer is formed. However, the molybdenum oxide layer has low resistance to wet processes. When the light emitting layer is formed, the molybdenum oxide layer may be damaged. In some cases, the molybdenum oxide layer may be dissolved in the organic light emitting ink. As a result, the technique disclosed in Patent Document 2 has a problem that an organic EL element having high light emission characteristics and long life characteristics cannot be obtained.

JP 2006-286243 A JP 2002-367784 A

  The present invention has been made in view of the above-described problems of the prior art, and its problem is that it can be easily manufactured, has a long life, and does not reduce manufacturing efficiency. A method for producing an organic EL element that prevents printing misalignment when supplying organic light-emitting ink to a plurality of pixel areas defined by the printing method by a relief printing method and does not cause color mixing in an organic light-emitting layer formed in the pixel area Another object of the present invention is to provide an organic EL element obtained by the production method, an illumination device using the organic EL element, a planar light source, and a display device.

  In order to solve the above problems, the present invention provides an organic EL element manufacturing method adopting the following configuration, an organic EL element obtained by the manufacturing method, an illumination device using the organic EL element, a planar light source, and A display device is provided.

[1] An anode, a cathode, an organic light emitting layer disposed between the anode and the cathode, and a metal-doped molybdenum oxide layer disposed between the anode and the organic light emitting layer, and substantially parallel to each other A method for producing an organic electroluminescent element provided on a support substrate having a plurality of partition walls placed on
Preparing a substrate having an anode formed on a support substrate having the partition;
A metal-doped molybdenum oxide layer forming step;
An organic light emitting layer forming step of forming an organic light emitting layer by supplying an organic light emitting ink containing an organic light emitting material between the partition walls;
Have
In the organic light emitting layer forming step, the organic light emitting ink is continuously provided along the longitudinal direction of the partition using a relief printing plate having a convex portion corresponding to the concave groove in the concave groove between the plurality of partition walls. A method for producing an organic electroluminescent element, characterized by comprising:

[2] The method for producing an organic electroluminescent element according to [1], wherein in the metal-doped molybdenum oxide layer forming step, a metal-doped molybdenum oxide layer is formed by simultaneously depositing molybdenum oxide and a dopant metal. .

[3] The method for producing an organic electroluminescent element according to the above [1] or [2], further comprising a step of heating the metal-doped molybdenum oxide layer formed in the metal-doped molybdenum oxide layer forming step.

[4] The method for manufacturing an organic electroluminescence element according to any one of [1] to [3], wherein the visible light transmittance of the metal-doped molybdenum oxide layer is 50% or more.

[5] Any one of the above [1] to [4], wherein the dopant metal contained in the metal-doped molybdenum oxide layer is selected from the group consisting of transition metals, metals of Group 13 of the periodic table, and mixtures thereof. The manufacturing method of the organic electroluminescent element of description.

[6] The method for producing an organic electroluminescent element according to the above [6], wherein aluminum is used as the dopant metal.

[7] The organic electroluminescent element according to any one of [1] to [6], wherein a ratio of a dopant metal contained in the metal-doped molybdenum oxide layer is 0.1 to 20.0 mol%. Manufacturing method.

[8] The above-described relief printing plate is cylindrical or columnar, and the plurality of protrusions are arranged so that a longitudinal direction of the plurality of protrusions overlaps a circumferential direction. The manufacturing method of the organic electroluminescent element as described in any one of [1]-[7].

[9] An organic electroluminescence device obtained by the method for producing an organic electroluminescence device according to any one of [1] to [8].

[10] An illumination device comprising the organic electroluminescence element as described in [9].

[11] A planar light source comprising the organic electroluminescence element according to [9].

[12] A display device comprising the organic electroluminescence element according to [9].

According to the method for producing an organic EL device according to the present invention, since the inorganic oxide layer and the layer laminated thereon can be easily and with high quality, the production is easy, and the resulting organic The EL element has good light emission characteristics and a long life. In addition, the organic EL device manufacturing method according to the present invention continuously supplies the organic light emitting ink along the longitudinal direction of the partition walls to form a light emitting layer, so that the alignment accuracy in the longitudinal direction of the partition walls is increased. The manufacturing efficiency can be improved while forming the light emitting layer with high accuracy.
Therefore, the organic EL element of the present invention can be suitably used as a display device such as a lighting device, a planar light source, and a flat panel display.

  Below, the manufacturing method of the organic EL element concerning this invention and the structure of the organic EL element obtained by this manufacturing method are demonstrated. Note that the scale of each member in the drawings shown in the following description may differ from the actual scale. Moreover, although members, such as an electrode lead wire, also exist in an organic EL element, description and illustration are abbreviate | omitted since it is not directly related as description of this invention.

  The organic EL device manufacturing method according to the present invention includes an anode, a cathode, an organic light emitting layer (hereinafter sometimes simply referred to as “light emitting layer”) disposed between the anode and the cathode, the anode, and the above. A method for producing an organic electroluminescence device provided on a support substrate having a plurality of partition walls, each of which includes a metal-doped molybdenum oxide layer disposed between organic light-emitting layers and is placed substantially parallel to each other, A step of preparing a substrate in which an anode is formed on a support substrate having the partition; a step of forming a metal-doped molybdenum oxide layer; and an organic light-emitting ink containing an organic light-emitting material is supplied between the partitions. An organic light emitting layer forming step, and in the organic light emitting layer forming step, in the concave groove between the plurality of partition walls, using a relief printing plate provided with a convex portion corresponding to the concave groove, Bulkhead Along the longitudinal direction, characterized by continuously supplying the organic light-emitting ink.

  1-3 is a figure for demonstrating one Embodiment of the manufacturing method of the organic EL element which concerns on this invention, About the formation method of the organic light emitting layer in the manufacturing method of the organic electroluminescent element which concerns on this embodiment. Show.

(substrate)
The supporting substrate 1 may be any substrate that does not change in the process of forming the organic EL element, and may be a rigid substrate or a flexible substrate. For example, a glass plate, a plastic plate, a polymer film, a silicon plate, and a laminate of these. The laminated board etc. which were made are used suitably. Further, a plastic, a polymer film or the like that has been subjected to a low water permeability treatment can also be used. A commercially available substrate can be used as the substrate. Moreover, the said board | substrate can also be manufactured by a well-known method.

  In the bottom emission type organic EL element that extracts light from the support substrate 1, the support substrate 1 having a high light transmittance in the visible light region is preferably used. In the top emission type organic EL element that extracts light from the cathode side, the support substrate 1 may be transparent or opaque.

  In addition, as said commercially available board | substrate, there also exists a board | substrate with which the below-mentioned partition and anode were formed on the support substrate. When such a commercially available substrate is used, the following anode formation step and partition formation step can be omitted in the manufacturing method of this embodiment.

(anode)
The anode 2 formed on the support substrate 1 is an electrode exhibiting optical transparency when light is extracted from the support substrate 1 and functions as an anode.
The anode 2 can be made of a metal oxide, metal sulfide or metal thin film having high electrical conductivity, and can preferably be used with a high transmittance, and is a layer provided between the anode 2 and the light emitting layer. It can be appropriately selected and used according to the constituent materials. As the material of the anode 2, for example, a thin film such as indium oxide, zinc oxide, tin oxide, indium tin oxide (abbreviated as ITO), indium zinc oxide (abbreviated as IZO), gold, platinum, silver, and copper is used. . Among these, ITO, IZO, and tin oxide are preferable.

  Further, as a constituent material of the anode 2, an organic transparent conductive film such as polyaniline or a derivative thereof, polythiophene or a derivative thereof may be used.

  Further, from the viewpoint of facilitating charge injection into the light emitting layer, a conductive polymer such as a phthalocyanine derivative and a polythiophene derivative, Mo oxide, amorphous carbon, fluoride is formed on the surface of the anode 2 on the light emitting layer side. You may provide a 1-200 nm layer, such as carbon and a polyamine compound, or a layer with an average film thickness of 10 nm or less made of a metal oxide, metal fluoride, organic insulating material, or the like.

  The film thickness of the anode 2 can be appropriately selected in consideration of light transmittance and electrical conductivity, and is, for example, 5 nm to 10 μm, preferably 10 nm to 1 μm, more preferably 20 nm to 500 nm. .

(Anode formation process)
A substrate made of any of the aforementioned substrate materials is prepared. When a plastic substrate having high gas and liquid permeability is used, a lower sealing film is formed on the substrate as necessary.

  Next, an anode is patterned on the prepared substrate using any of the anode materials described above. When this anode is used as a transparent electrode, as described above, a transparent electrode material such as ITO, IZO, tin oxide, zinc oxide, indium oxide, and zinc aluminum composite oxide is used. For example, in the case of using ITO, the electrode pattern is formed as a uniform deposited film on the substrate by a sputtering method, and then patterned into a stripe shape by photolithography.

(Partition forming process)
FIG. 1 is a plan view of a substrate on which a partition wall is formed, and FIG. 2 is a cross-sectional view of the substrate as seen from the section line II-II in FIG. On the anode 2, a plurality of partition walls 13a arranged in a stripe shape are formed. Here, “arranged in a stripe shape” means that the plurality of partition walls 13 a are arranged substantially in parallel in a vertical stripe shape or a horizontal stripe shape.
In the present embodiment, the anodes 2 are arranged in stripes, and the partition walls 13 a are arranged so as to overlap the gaps between the anodes 2 when viewed from one side in the thickness direction of the substrate 1.

  In addition, a plurality of pixel regions in which pixels are formed may be set along the partition wall 13a between the partition walls 13a, and the height from the substrate 1 is lower than the partition wall 13a between the adjacent pixel regions 14. An electrical insulating layer 13b may be provided. In the present embodiment, an electrical insulating layer 13b is provided on the substrate 1 on which the anode 2 is formed.

The electrical insulating film 13b is usually formed by forming an insulating film having a thickness of 0.1 to 0.2 μm made of an inorganic insulating material such as SiO ₂ or SiN by a known method such as a plasma CVD method or a sputtering method, and then photolithography. And etching. The region where the insulating film is removed by this patterning is a region corresponding to the pixel region 14, and the film remaining without being removed becomes the electrical insulating layer 13b. The partition wall 13a is further provided on the above-described electrical insulating layer 13b.
In the case where the electrical insulating layer 13b is not provided, the anode 2 is exposed in a band shape between the partition walls 13a. This band-shaped region becomes the pixel region 14.

  The main role of the partition wall 13a is to prevent insulation between adjacent pixels separated by the partition wall 13a and to prevent color mixing between adjacent pixels. Therefore, the height dimension is set high. On the other hand, the role of the electrical insulating layer 13b is to provide insulation between a plurality of pixels of the same color arranged along the partition wall 13a, and has no role in preventing color mixing. Therefore, the partition wall 13a may be formed somewhat thicker than the total thickness of the laminated films such as the metal-doped molybdenum oxide layer and the organic light emitting layer formed on the pixel region 14. From this standard, the height of the partition wall 13a is preferably set to 2 to 3 μm, and the height of the electric insulating layer 13b is preferably set to 0.1 to 0.2 μm. Note that the electrical insulating layer 13b can be omitted depending on the electrical conductivity of the organic material.

The method for manufacturing the partition wall 13a having the above-described structure is not particularly limited. For example, the partition wall 13a can be manufactured as follows.
First, an insulating film having a thickness of 0.1 to 0.2 μm made of an inorganic insulating material such as SiO ₂ or SiN is formed by a known method such as a plasma CVD method or a sputtering method, and then a plurality of pixels are formed by photolithography and etching. By removing the region and patterning in a lattice shape, the electrical insulating layer 13b is formed.
Next, a photoresist layer having a thickness of 2 to 3 μm is formed on the grid-like electrical insulating layer 13b, and this photoresist layer is exposed through a stripe-shaped mask, and a plurality of anodes arranged in a stripe shape. Development is performed so that the resist layer remains only between the two, and heat curing is performed.
The resist layer patterned in the stripe form constitutes the partition wall 13a.

  The photosensitive material (photoresist composition) for forming the photoresist layer can be applied by a coating method using a spin coater, bar coater, roll coater, die coater, gravure coater, slit coater or the like. .

  The insulating photosensitive material forming the partition wall 13a may be either a positive resist or a negative resist. It is important that the partition wall 13a is insulative. If the partition wall 13a is not insulative, a current flows between the anodes 2 defined by the partition wall, resulting in display defects.

  As the insulating photosensitive material for constituting the partition wall 13a, specifically, polyimide, acrylic resin, and novolak resin photosensitive compounds can be used. This photosensitive material may contain a light-shielding material for the purpose of improving the display quality of the organic EL element.

  In order to impart ink repellency to the surface of the insulating partition wall 13a, an ink repellant substance may be added to the photosensitive material for forming the partition wall. Alternatively, after the insulating partition wall 13a is formed, the surface of the partition wall may be coated with an ink repellent material to impart ink repellency to the partition wall surface. This ink repellency must be ink repellant both for the solution for forming the “layer provided between the anode and the light emitting layer” described later and for the ink for the organic light emitting layer. preferable.

  As a substance used when an ink repellent substance is added to the photosensitive material, a silicone compound or a fluorine-containing compound is used. Since these ink repellent compounds exhibit ink repellency in both the organic light emitting ink (coating liquid) used for forming the organic light emitting layer described later and the organic material ink (coating liquid) such as the hole transport layer, it is preferable. Can be used.

As a method of forming an ink-repellent film on the surface of the partition wall after forming the partition wall 13a, a method of applying a coating liquid containing an ink-repellent component to the surface of the partition wall, vaporizing the ink-repellent component and depositing on the partition wall surface. Examples thereof include a method of modifying the surface by substituting the functional group of the organic material on the partition wall surface with fluorine. Specifically, as the deposition method by the latter vapor phase method, there is a method of imparting liquid repellency to the partition wall surface by converting CF ₄ gas into plasma using a vacuum plasma apparatus and causing a fluorine component to act on the partition wall surface. Can be mentioned.

(Metal-doped molybdenum oxide layer)
After the formation of the insulating partition wall 13a, the metal-doped molybdenum oxide layer 3 is provided between the anode 2 and a light emitting layer (not shown).
In addition to the metal-doped molybdenum oxide layer 3, a predetermined layer may be further provided between the anode 2 and the light emitting layer. Examples of the layer provided between the anode 2 and the light emitting layer include a hole injection layer, a hole transport layer, and an electron block layer described later.
Therefore, there are an element configuration in which only the metal-doped molybdenum oxide layer is provided between the anode 2 and the light emitting layer, and an element configuration in which the metal-doped molybdenum oxide layer and other layers are provided.
Examples of the layer provided between the light emitting layer and the cathode include an electron injection layer, an electron transport layer, and a hole blocking layer.

  The metal-doped molybdenum oxide layer contains molybdenum oxide and a dopant metal, and preferably consists essentially of molybdenum oxide and dopant metal. More specifically, the proportion of the total of the molybdenum oxide and the dopant metal in the total amount of the material constituting the metal-doped molybdenum oxide layer is preferably 98% by mass or more, more preferably 99% by mass or more, and still more preferably Is 99.9% by mass or more.

The metal-doped molybdenum oxide layer preferably serves also as a hole injection layer, or is provided in direct contact with the light emitting layer or the hole injection layer. More specific arrangements of the metal-doped molybdenum oxide layer are shown in the following (i) to (v).
(Ii) provided in contact with the anode and the hole transport layer (ii) provided in contact with the anode and the electron blocking layer (iii) provided in contact with the hole injection layer and the light emitting layer (iv) the hole injection layer and Provided in contact with the electron blocking layer (v) Provided in contact with the anode and the light emitting layer

  The visible light transmittance of the metal-doped molybdenum oxide layer is preferably 50% or more. By having a visible light transmittance of 50% or more, it can be suitably used for an organic EL device that emits light through the metal-doped molybdenum oxide layer.

The dopant metal contained in the metal-doped molybdenum oxide layer is preferably a transition metal, a Group 13 metal of the periodic table, or a mixture thereof, more preferably aluminum, nickel, copper, chromium, titanium, silver, gallium, zinc. , Neodymium, europium, holmium, cerium, and more preferably aluminum. On the other hand, it is preferable to employ MoO ₃ as the molybdenum oxide. When MoO ₃ is formed by an evaporation method such as vacuum evaporation, the stoichiometric composition ratio of Mo and O in the deposited film may deviate from MoO _3. It can be preferably used for an EL element.

  It is preferable that the ratio of the dopant metal contained in the metal doped molybdenum oxide layer is 0.1 to 20.0 mol%. When the content ratio of the dopant metal is within the above range, a metal-doped molybdenum oxide layer having good process resistance can be obtained.

  Although the thickness of the said metal dope molybdenum oxide layer is not specifically limited, It is preferable that it is 1-100 nm.

  A method for forming the metal-doped molybdenum oxide layer is not particularly limited, but a preferred method is a so-called co-evaporation method in which molybdenum oxide and a dopant metal are simultaneously deposited on a layer on which the metal-doped molybdenum oxide layer is laminated. It can be illustrated as one of these. For example, deposition can be carried out on an anode or cathode layer provided on a substrate to obtain a metal-doped molybdenum oxide layer in direct contact with the electrode. Alternatively, after an electrode is provided on the substrate, one or more other layers such as a light emitting layer, a charge injection layer, a charge transport layer, or a charge blocking layer are provided on the electrode, and deposition is further performed thereon. A metal-doped molybdenum oxide layer in direct contact can be obtained.

  Deposition can be performed by vacuum evaporation, molecular beam evaporation, sputtering or ion plating, ion beam evaporation, or the like. By introducing plasma into the film formation chamber, a plasma assisted vacuum deposition method with improved reactivity and film formability can be used. Examples of the evaporation source of the vacuum deposition method include resistance heating, electron beam heating, high frequency induction heating, and laser beam heating. As a simpler method, resistance heating, electron beam heating, and high frequency induction heating are preferable. There are a DC sputtering method, an RF sputtering method, an ECR sputtering method, a conventional sputtering method, a magnetron sputtering method, an ion beam sputtering method, a counter target sputtering method, and the like, and any of these methods can be used. In order not to damage the lower layer of the metal-doped molybdenum oxide layer, it is preferable to use a magnetron sputtering method, an ion beam sputtering method, or a counter target sputtering method.

Note that during film formation, vapor deposition can be performed by introducing a gas containing oxygen or an oxygen element into the atmosphere. Further, as a material for depositing the metal-doped molybdenum oxide layer, MoO ₃ or a dopant metal alone is usually used, but molybdenum alone, an oxide of MoO ₂ or a dopant metal, an alloy of a dopant metal and molybdenum, or these A mixture of the above can be used.

The deposited metal-doped molybdenum oxide layer is subjected to other steps such as heating, UV-O ₃ treatment, atmospheric exposure, etc. as it is or optionally. Among these, heat treatment is preferably performed in order to improve the transmittance.

The heating can be performed at 50 to 350 ° C. for 1 to 120 minutes. The UV-O ₃ treatment can be performed by irradiating with ultraviolet rays at an intensity of 1 to 100 mW / cm ² for 5 seconds to 30 minutes and in an atmosphere having an ozone concentration of 0.001 to 99%. The exposure to the atmosphere can be performed by leaving it in the atmosphere at a humidity of 40 to 95% and a temperature of 20 to 50 ° C. for 1 to 20 days.

(Layer provided between the anode and the light emitting layer)
At least a metal-doped molybdenum oxide layer is provided between the anode and the light emitting layer. As described above, a hole injection layer, a hole transport layer, an electron blocking layer, and the like may be provided in addition to the metal-doped molybdenum oxide layer. The metal-doped molybdenum oxide layer functions as at least one of these hole injection layer, hole transport layer, and electron block layer.

  The hole injection layer is a layer having a function of improving the hole injection efficiency from the anode 2. The hole transport layer is a layer having a function of improving hole injection from the anode, the hole injection layer, or the hole transport layer closer to the anode. The electron blocking layer is a layer having a function of blocking electron transport. In the case where the hole injection layer and / or the hole transport layer has a function of blocking electron transport, these layers may also serve as an electron blocking layer. The fact that the electron blocking layer has a function of blocking electron transport makes it possible, for example, to produce an element that allows only electron current to flow and confirm the blocking effect by reducing the current value.

(Hole injection layer)
As described above, the hole injection layer can be provided between the anode and the hole transport layer or between the anode and the light emitting layer. As a material constituting the hole injection layer, a known material can be appropriately used, and there is no particular limitation. For example, phenylamine, starburst amine, phthalocyanine, hydrazone derivative, carbazole derivative, triazole derivative, imidazole derivative, oxadiazole derivative having amino group, vanadium oxide, tantalum oxide, tungsten oxide, molybdenum oxide, ruthenium oxide And oxides such as aluminum oxide, amorphous carbon, polyaniline, polythiophene derivatives, and the like.

  As a film formation method of the hole injection layer, for example, film formation from a solution containing a material (hole injection material) that becomes the hole injection layer can be mentioned. The solvent used for film formation from a solution is not particularly limited as long as it dissolves the hole injection material. Chlorine solvents such as chloroform, methylene chloride and dichloroethane, ether solvents such as tetrahydrofuran, toluene, Mention may be made of aromatic hydrocarbon solvents such as xylene, ketone solvents such as acetone and methyl ethyl ketone, ester solvents such as ethyl acetate, butyl acetate and ethyl cellosolve acetate, and water.

  As a film forming method from a solution, 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, a spray coating method, a screen printing method, Examples of the application method include a flexographic printing method, an offset printing method, and an ink jet printing method. Among these, it is preferable to form a film using a relief printing method described later.

  The thickness of the hole injection layer is preferably about 5 to 300 nm. If the thickness is less than 5 nm, the production tends to be difficult. On the other hand, if the thickness exceeds 300 nm, the driving voltage and the voltage applied to the hole injection layer tend to increase.

(Hole transport layer)
The material constituting the hole transport layer is not particularly limited. For example, N, N′-diphenyl-N, N′-di (3-methylphenyl) 4,4′-diaminobiphenyl (TPD), 4 , 4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPB) and other aromatic amine derivatives, polyvinylcarbazole or derivatives thereof, polysilane or derivatives thereof, aromatic amines in the side chain or main chain Polysiloxane derivative having pyrazole, pyrazoline derivative, arylamine derivative, stilbene derivative, triphenyldiamine derivative, polyaniline or derivative thereof, polythiophene or derivative thereof, polyarylamine or derivative thereof, polypyrrole or derivative thereof, poly (p-phenylene vinylene) Or its derivatives, or poly (2,5-thienylene vinylene) or a derivative thereof is exemplified.

  Among these, as the hole transport material used for the hole transport layer, polyvinyl carbazole or a derivative thereof, polysilane or a derivative thereof, a polysiloxane derivative having an aromatic amine compound group in a side chain or a main chain, polyaniline or a derivative thereof, Polymeric hole transport materials such as polythiophene or derivatives thereof, polyarylamine or derivatives thereof, poly (p-phenylene vinylene) or derivatives thereof, or poly (2,5-thienylene vinylene) or derivatives thereof are preferred, and more preferred Is polyvinyl carbazole or a derivative thereof, polysilane or a derivative thereof, and a polysiloxane derivative having an aromatic amine in the side chain or main chain. In the case of a low-molecular hole transport material, it is preferably used by being dispersed in a polymer binder.

  The method for forming the hole transport layer is not particularly limited, but in the case of a low molecular hole transport material, film formation from a mixed solution containing a polymer binder and a hole transport material can be exemplified. Examples of molecular hole transport materials include film formation from a solution containing a hole transport material.

The solvent used for film formation from a solution is not particularly limited as long as it dissolves the hole transport material, and is a chlorine-based solvent such as chloroform, methylene chloride, dichloroethane, an ether-based solvent such as tetrahydrofuran, toluene, Examples thereof include aromatic hydrocarbon solvents such as xylene, ketone solvents such as acetone and methyl ethyl ketone, and ester solvents such as ethyl acetate, butyl acetate, and ethyl cellosolve acetate.
Examples of the film forming method from a solution include the same coating method as the above-described film forming method of the hole injection layer, and it is preferable to form a film using the relief printing method described above.

  As the polymer binder to be mixed, those that do not extremely inhibit charge transport are preferable, and those that weakly absorb visible light are preferably used. For example, polycarbonate, polyacrylate, polymethyl acrylate, polymethyl methacrylate, polystyrene, poly Examples thereof include vinyl chloride and polysiloxane.

  The thickness of the hole transport layer is not particularly limited, but can be appropriately changed according to the intended design, and is preferably about 1 to 1000 nm. If the thickness is less than the lower limit value, production tends to be difficult or the effect of hole transport is not sufficiently obtained. On the other hand, if the thickness exceeds the upper limit value, the driving voltage and the hole transport layer are increased. There is a tendency that the voltage applied to is increased. Therefore, the thickness of the hole transport layer is preferably 1 to 1000 nm as described above, more preferably 2 nm to 500 nm, and still more preferably 5 nm to 200 nm.

(Light emitting layer forming step)
After the metal doped molybdenum oxide layer 3 and other layers as necessary are formed, a light emitting layer is formed. The light-emitting layer forming step is characterized in that an organic light-emitting ink containing an organic light-emitting material is applied using a relief printing method, and the plurality of partition walls are used as a relief printing plate used in that case, as shown in FIG. A relief printing plate 20 having a plurality of convex portions 21 having a width corresponding to the width between the plurality of partition walls 13a and arranged in stripes at intervals corresponding to the intervals between the plurality of partition walls 13a is used. That is. Furthermore, the relief printing plate 20 is preferably cylindrical or columnar, and the plurality of convex portions 21 are preferably arranged so that the longitudinal direction of the convex portions overlaps the circumferential direction.

  In the case of manufacturing a multicolor organic EL element, the organic light emitting ink of the same color attached to the convex portion 21 corresponding to the concave groove 15 is formed in each concave groove defined by the partition wall 13a. Applied. Therefore, even in the case of multicolor printing, according to the above configuration, if the alignment of the convex portion 21 of the relief printing plate 20 with respect to the concave groove 15 between the partition walls 13a is made accurate, the alignment accuracy in the printing direction becomes moderate. However, each color of organic light-emitting ink is accurately applied.

(Constituent material of light emitting layer)
The light emitting layer usually has an organic substance that mainly emits fluorescence or phosphorescence, and may further contain a dopant material. The organic substance may be a low molecular compound or a high molecular compound, and the light emitting layer preferably contains a high molecular compound having a polystyrene-equivalent number average molecular weight of 10 ³ to 10 ⁸ . Examples of the light emitting material constituting the light emitting layer include the following. In addition, a plurality of light emitting layers may be disposed between the anode and the cathode without being limited to a single light emitting layer.

(Dye material)
Examples of the dye-based material include cyclopentamine derivatives, quinacridone derivatives, coumarin derivatives, tetraphenylbutadiene derivative compounds, triphenylamine derivatives, oxadiazole derivatives, pyrazoloquinoline derivatives, distyrylbenzene derivatives, distyrylarylene derivatives, Examples include pyrrole derivatives, thiophene ring compounds, pyridine ring compounds, perinone derivatives, perylene derivatives, oligothiophene derivatives, trifumanylamine derivatives, oxadiazole dimers, and pyrazoline dimers.

(Metal complex materials)
Examples of the metal complex material 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, azomethyls. Zinc complex, porphyrin zinc complex, europium complex, etc., which has Al, Zn, Be, etc. as the central metal or rare earth metals such as Tb, Eu, Dy, etc., and oxadiazole, thiadiazole, phenylpyridine, phenylbenzo as ligands Examples thereof include metal complexes having an imidazole or quinoline structure.

(Polymer material)
Polymeric materials include polyparaphenylene vinylene derivatives, polythiophene derivatives, polyparaphenylene derivatives, polysilane derivatives, polyacetylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, and polymerized chromophores and metal complex light emitting materials. Etc.

Among the light emitting materials, examples of the material that emits 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 materials that emit red light include coumarin derivatives, thiophene ring compounds, and polymers thereof, polyparaphenylene vinylene derivatives, polythiophene derivatives, and polyfluorene derivatives. Among these, polymer materials such as polyparaphenylene vinylene derivatives, polythiophene derivatives, and polyfluorene derivatives are preferable.

(Dopant material)
A dopant can be added to the light emitting layer for the purpose of improving the light emission efficiency and changing the light emission wavelength. Examples of such dopants include perylene derivatives, coumarin derivatives, rubrene derivatives, quinacridone derivatives, squalium derivatives, porphyrin derivatives, styryl dyes, tetracene derivatives, pyrazolone derivatives, decacyclene, phenoxazone, and the like. In addition, the thickness of such a light emitting layer is about 20-2000 mm normally.

  The organic light emitting ink is prepared by dissolving or stably dispersing the organic light emitting material in a solvent. Examples of the solvent for dissolving or dispersing the organic light emitting material include toluene, xylene, acetone, anisole, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and the like alone or a mixed solvent thereof. Among these, aromatic organic solvents such as toluene, xylene, and anisole are preferable because they have good solubility of the organic light emitting material.

  In addition, you may add surfactant, antioxidant, a viscosity modifier, a ultraviolet absorber, etc. to organic luminescent ink as needed.

(Layer provided between the cathode and the light emitting layer)
After the formation of the light emitting layer, one layer or a plurality of predetermined layers are provided as necessary. Between the light emitting layer and the cathode, an electron injection layer, an electron transport layer, a hole blocking layer, and the like are provided.
When both the electron injection layer and the electron transport layer are provided between the cathode and the light emitting layer, the layer in contact with the cathode is called an electron injection layer, and the layers other than the electron injection layer are called electron transport layers. is there.
The electron injection layer is a layer having a function of improving electron injection efficiency from the cathode. The electron transport layer is a layer having a function of improving electron injection from the cathode, the electron injection layer, or the electron transport layer closer to the cathode. The hole blocking layer is a layer having a function of blocking hole transport. In the case where the electron injection layer and / or the electron transport layer have a function of blocking hole transport, these layers may also serve as the hole blocking layer. The fact that the hole blocking layer has a function of blocking hole transport makes it possible, for example, to produce an element that allows only a hole current to flow, and confirm the blocking effect by reducing the current value.

(Electron transport layer)
As the material for forming the electron transport layer, known materials can be used, such as oxadiazole derivatives, anthraquinodimethane or derivatives thereof, benzoquinone or derivatives thereof, naphthoquinone or derivatives thereof, anthraquinones or derivatives thereof, tetracyanoanthraquinodi. Examples include methane or its derivatives, fluorenone derivatives, diphenyldicyanoethylene or its derivatives, diphenoquinone derivatives, or metal complexes of 8-hydroxyquinoline or its derivatives, polyquinoline or its derivatives, polyquinoxaline or its derivatives, polyfluorene or its derivatives, etc. The

  Of these, oxadiazole derivatives, benzoquinone or derivatives thereof, anthraquinones or derivatives thereof, or metal complexes of 8-hydroxyquinoline or derivatives thereof, polyquinoline or derivatives thereof, polyquinoxaline or derivatives thereof, polyfluorene or derivatives thereof are preferred, 2- (4-biphenylyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, benzoquinone, anthraquinone, tris (8-quinolinol) aluminum, and polyquinoline are more preferable.

  The electron injection layer and the hole injection layer may be collectively referred to as a charge injection layer, and the electron transport layer and the hole transport layer may be collectively referred to as a charge transport layer.

(Electron injection layer)
Depending on the type of the light emitting layer, the electron injection layer may be an alkali metal or alkaline earth metal, an alloy containing one or more of the above metals, an oxide, halide and carbonate of the metal, or a mixture of the substances. Etc.

  Examples of the alkali metal or its oxide, halide, carbonate include lithium, sodium, potassium, rubidium, cesium, lithium oxide, lithium fluoride, sodium oxide, sodium fluoride, potassium oxide, potassium fluoride, oxide Examples include rubidium, rubidium fluoride, cesium oxide, cesium fluoride, and lithium carbonate.

  Examples of the alkaline earth metals or oxides, halides and carbonates thereof include magnesium, calcium, barium, strontium, magnesium oxide, magnesium fluoride, calcium oxide, calcium fluoride, calcium fluoride, barium oxide, fluorine. Barium fluoride, strontium oxide, strontium fluoride, magnesium carbonate and the like.

  Furthermore, a metal, a metal oxide, an organometallic compound doped with a metal salt, an organometallic complex compound, or a mixture thereof can also be used as a material for the electron injection layer.

This electron injection layer may have a stacked structure in which two or more layers are stacked. Specifically, Li / Ca etc. are mentioned. This electron injection layer is formed by vapor deposition, sputtering, printing, or the like.
The thickness of the electron injection layer is preferably about 1 nm to 1 μm.

(cathode)
A material for the cathode is preferably a material having a small work function and easy electron injection into the light emitting layer. Further, as the material of the cathode, a material having high electric conductivity and high visible light reflectance is preferable. Specific examples of such cathode materials include metals, metal oxides, alloys, graphite or graphite intercalation compounds, and inorganic semiconductors such as zinc oxide (ZnO).

  As the metal, an alkali metal, an alkaline earth metal, a transition metal, a group 13 metal of the periodic table, or the like can be used. Specific examples of these metals include lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, gold, silver, platinum, copper, manganese, titanium, cobalt, nickel, tungsten, tin, and aluminum. , Scandium, vanadium, zinc, yttrium, indium, cerium, samarium, europium, terbium, ytterbium, and the like.

  Examples of the alloy include an alloy containing at least one of the above metals. Specifically, a magnesium-silver alloy, a magnesium-indium alloy, a magnesium-aluminum alloy, an indium-silver alloy, a lithium-aluminum alloy, Examples thereof include a lithium-magnesium alloy, a lithium-indium alloy, and a calcium-aluminum alloy.

  The cathode is an electrode having optical transparency as required. Examples of such materials include conductive oxides such as indium oxide, zinc oxide, tin oxide, ITO, and IZO; polyaniline or derivatives thereof, polythiophene or Examples thereof include conductive organic substances such as derivatives thereof.

  Note that the cathode may have a laminated structure of two or more layers. Moreover, an electron injection layer may be used as a cathode.

  The film thickness of the cathode can be appropriately selected in consideration of electric conductivity and durability, but is, for example, 10 nm to 10 μm, preferably 20 nm to 1 μm, and more preferably 50 nm to 500 nm.

  Examples of the method for forming the cathode include a vacuum deposition method, a sputtering method, and a laminating method in which a metal thin film is thermocompression bonded. Note that the cathode may have a laminated structure of two or more layers.

In the organic EL element of the present embodiment, a combination example of layer configurations from the anode 2 to the cathode is shown below.
a) Anode / hole injection layer / light emitting layer / cathode b) Anode / hole injection layer / light emitting layer / electron injection layer / cathode c) Anode / hole injection layer / light emitting layer / electron transport layer / cathode d) Anode / Hole injection layer / light emitting layer / electron transport layer / electron injection layer / cathode e) anode / hole transport layer / light emitting layer / cathode f) anode / hole transport layer / light emitting layer / electron injection layer / cathode g) Anode / hole transport layer / light emitting layer / electron transport layer / cathode h) anode / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode i) anode / hole injection layer / hole transport layer / Emissive layer / cathode j) anode / hole injection layer / hole transport layer / emission layer / electron injection layer / cathode k) anode / hole injection layer / hole transport layer / emission layer / electron transport layer / cathode l) Anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode (here, the symbol “/” indicates that the layers sandwiching the symbol “/” are stacked adjacent to each other) Indicating that. Hereinafter the same.)
In a) to l), one of the layers provided between the anode and the light emitting layer is a metal-doped molybdenum oxide layer.

The organic EL device of the present embodiment may have two or more light-emitting layers, and as an organic EL device having two light-emitting layers, any one of the layer configurations a) to l) above. In this case, when the laminate sandwiched between the anode and the cathode is referred to as “repeating unit A”, the layer configuration shown in the following m) can be exemplified.
m) Anode / (Repeating Unit A) / Charge Injection Layer / (Repeating Unit A) / Cathode As an organic EL device having three or more light emitting layers, “(Repeating Unit A) / Charge Injection Layer” As the “repeating unit B”, the layer constitution shown in the following n) can be mentioned.
n) Anode / (Repeating unit B) x / (Repeating unit A) / Cathode The symbol “x” represents an integer of 2 or more, and (Repeating unit B) x is a laminate in which the repeating unit B is laminated in x stages. Represents the body.
Here, the charge generation layer is a layer that generates holes and electrons by applying an electric field. Examples of the charge generation layer include a thin film made of vanadium oxide, indium tin oxide (abbreviated as ITO), molybdenum oxide, or the like.

  In the organic EL device of this embodiment, an insulating layer having a thickness of 2 nm or less may be provided adjacent to the electrode in order to further improve the adhesion with the electrode or improve the charge injection property from the electrode. In addition, a thin buffer layer may be inserted between each of the aforementioned layers in order to improve adhesion at the interface or prevent mixing.

(Protective layer)
After the cathode is formed as described above, a protective layer (upper sealing film) that seals the light emitting function part in order to protect the light emitting function part having the anode-light emitting layer-cathode as a basic structure. Is formed. This protective layer usually has at least one inorganic layer and at least one organic layer. The number of stacked layers is determined as necessary. Basically, inorganic layers and organic layers are alternately stacked.

  Note that the plastic substrate has higher permeability of gases such as oxygen and water than the glass substrate. Since a light emitting material such as a light emitting layer is easily oxidized and easily deteriorates by contact with oxygen, water, etc., when a plastic substrate is used as the substrate, the substrate is preliminarily subjected to a treatment for enhancing gas barrier properties. Is preferred. For example, it is preferable to stack a lower sealing film having a high barrier property against gas or the like on a plastic substrate, and then stack the light emitting function part on the lower sealing film. The lower sealing film is usually formed with the same configuration and the same material as the protective layer (upper sealing film).

  The organic EL device targeted by the method of the present invention may be a bottom emission type device that emits light from the light emitting layer to the outside from a transparent support substrate, or light from the light emitting layer may be a transparent cathode. It is also possible to use a top emission type element that transmits light from the transparent protective layer to the outside.

  The top emission type element may have a structure in which light from the light emitting layer is transmitted through the transparent cathode and emitted to the outside from the transparent protective layer.

  The organic EL element of the embodiment of the present invention as 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, or a display device.

  Examples of the display device including the organic EL element include an active matrix display device, a passive matrix display device, a segment display device, a dot matrix display device, and a liquid crystal display device. The 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, and is used as a light emitting element constituting each segment in a segment display device. In a liquid crystal display device, it is used as a backlight.

  In the present invention, a relief plate is provided with a metal-doped molybdenum oxide layer between the anode and the light emitting layer, and the concave groove 15 formed between the plurality of partition walls and the anode is provided with a convex portion corresponding to the concave groove 15. The light emitting layer is formed by continuously supplying the organic light emitting ink along the longitudinal direction of the partition wall using a printing plate.

  When manufacturing an organic EL element, when using a substrate provided with a grid-like partition wall as in the past, a plurality of protrusions regularly arranged in the row direction and the column direction so as to correspond to the grid-like partition wall. Printing is performed using a relief printing plate having a portion. Therefore, when printing, it is necessary to align the row direction and the column direction, and the tolerance in printing accuracy is small. That is, in the conventional manufacturing method using a substrate provided with a grid-like partition wall, the plate cylinder direction of the relief printing plate, the positional accuracy in the circumferential direction, and the angular accuracy in the feeding direction of the substrate become strict, and efficient manufacturing is difficult. there were. On the other hand, in the present invention, printing is performed using a relief printing plate having striped (vertical striped or horizontal striped) convex portions, so there is no need to align the longitudinal direction of the striped partition walls. Just align the direction. As a result, the alignment accuracy in the longitudinal direction of the partition walls can be relaxed, and the manufacturing efficiency of the element can be improved.

  In the present invention, a metal-doped molybdenum oxide layer is formed between the anode and the light-emitting layer. The metal-doped molybdenum oxide layer has a very high resistance to a wet process. Therefore, when forming the light emitting layer after forming the metal doped molybdenum oxide layer, the metal doped molybdenum oxide layer is not easily damaged even if the coating method (wet process) using the relief printing plate is used. do not do. As a result, the metal-doped molybdenum oxide layer does not impair the function as a layer, for example, the function as a hole injection layer.

  Therefore, according to the present invention, a long-life device is obtained by providing a metal-doped molybdenum oxide layer, and the long-life device is obtained by a specific organic light-emitting ink supply method using a relief printing plate. By forming the film, it can be obtained at a low cost with a simple process. The method for producing an organic electroluminescent element according to the present invention is highly effective and useful particularly when a light emitting layer is formed by coating on the surface of a metal-doped molybdenum oxide layer.

  Hereinafter, although a manufacture example and a comparative example are demonstrated, this invention is not limited to the following illustrations.

  In the following Production Examples 1 to 6 and Comparative Examples 1 and 2, in order to confirm the effect of providing the metal-doped molybdenum oxide layer between the anode and the light emitting layer, the metal doping was performed between the anode and the light emitting layer. An organic EL device provided with a molybdenum oxide layer was manufactured.

(Production Example 1)
(A: Deposition of Al-doped MoO ₃ on a glass substrate by a vacuum deposition method)
A plurality of glass substrates were prepared, one side of which was partially covered with a vapor deposition mask, and attached to the vapor deposition chamber using a substrate holder.

MoO ₃ powder (manufactured by Aldrich, purity 99.99%) was packed in a tungsten board for a box-type sublimation substance, covered with a cover with holes so that the material would not scatter, and set in a vapor deposition chamber. Al (manufactured by Koyo Chemical Co., Ltd., purity 99.999%) was put in a crucible and set in a vapor deposition chamber.

The degree of vacuum in the vapor deposition chamber is set to 3 × 10 ⁻⁵ Pa or less, MoO ₃ is gradually heated by a resistance heating method and sufficiently degassed, and Al is dissolved in the crucible by an electron beam and fully desorbed. After performing the gas, it was subjected to vapor deposition. The degree of vacuum during vapor deposition was 9 × 10 ⁻⁵ Pa or less. The film thickness and the deposition rate were constantly monitored with a crystal resonator. When the deposition rate of MoO ₃ was about 0.28 nm / second and the deposition rate of Al was about 0.01 nm / second, the main shutter was opened and film formation on the substrate was started. During deposition, the substrate was rotated so that the film thickness was uniform. Film formation was performed for about 36 seconds while controlling the vapor deposition rate to the above rate, and a substrate provided with a co-deposited film (metal-doped molybdenum oxide layer) having a thickness of about 10 nm was obtained. The composition ratio of Al to the total of MoO ₃ and Al in the film was about 3.5 mol%.

(B: Durability test)
After film formation, the obtained substrate was taken out into the atmosphere and the film surface was observed with an optical microscope (500 times). As a result, no crystal structure was observed, and it was confirmed that the film was in an amorphous state.
When the obtained substrate was exposed to pure water for 1 minute and observed again with an optical microscope, there was no change and the surface was not melted. In either case, the substrate was further exposed to pure water for 3 minutes, or the film was wiped with a non-woven fabric (trade name “Bencot”, manufactured by Ozu Sangyo Co., Ltd.) containing pure water and then visually observed. The membrane remained unchanged.

  Moreover, when the board | substrate obtained different from the board | substrate exposed to the said pure water was exposed to acetone for 1 minute and observed with the optical microscope, there was no change and the surface did not melt | dissolve. The substrate was further exposed to acetone for 3 minutes, or the film was wiped with a non-woven fabric containing acetone and visually confirmed. In either case, the film remained unchanged.

(C: Measurement of transmittance)
Further, the transmittance of the deposited film after film formation was measured using a transmittance / reflectance measuring apparatus (trade name “FilmTek 3000” manufactured by Scientific Computing International). The results are shown in (Table 1) below. The transmission spectrum rose from a wavelength of about 300 nm. The transmittance at a wavelength of 320 nm was 21.6%, and the transmittance at 360 nm was 56.6%. Compared to Comparative Example 1 described later, the transmittance was 3.6 times at 320 nm and 1.6 times at 360 nm.

(Production Example 2)
A substrate provided with a co-deposited film was obtained in the same manner as in Production Example 1 (A) except that oxygen was introduced into the chamber during the deposition. The amount of oxygen was controlled to 15 sccm by a mass flow controller. The degree of vacuum during vapor deposition was about 2.3 × 10 ⁻³ Pa. The thickness of the obtained co-deposited film (metal-doped molybdenum oxide layer) was about 10 nm, and the composition ratio of Al with respect to the total of MoO ₃ and Al in the film was about 3.5 mol%.

  After film formation, the durability of the obtained substrate was evaluated in the same manner as in Production Example 1 (B). No change was observed when exposed to either pure water or acetone.

(Production Example 3)
The vapor deposition rate was controlled in the same manner as in (A) of Production Example 1 except that the deposition rate was controlled to about 0.37 nm / second for MoO _{3 and} about 0.001 nm / second for Al. A substrate provided with a physical layer was obtained. The thickness of the obtained co-deposited film was about 10 nm, and the composition ratio of Al to the total of MoO ₃ and Al in the film was about 1.3 mol%.

  After film formation, the durability of the obtained substrate was evaluated in the same manner as in Production Example 1 (C). No change was observed when exposed to either pure water or acetone.

(Production Example 4)
The substrate obtained in (A) of Preparation Example 1 was placed in a clean oven in an air atmosphere and heat-treated at 250 ° C. for 60 minutes. After cooling, the transmittance of the deposited film (metal-doped molybdenum oxide layer) was measured in the same manner as in Example 1 (C). The results are shown in (Table 1) below. The transmittance at a wavelength of 320 nm was 28.9%, and the transmittance at 360 nm was 76.2%. Compared to Comparative Example 1 below, the transmittance was 4.7 times at 320 nm and 2.2 times at 360 nm.

(Comparative Example 1)
Except that Al was not deposited and only MoO ₃ was deposited at about 0.28 nm / second, the same operation as in Production Example 1 was performed to obtain a substrate provided with a deposited film having a thickness of about 10 nm.
After film formation, the obtained substrate was taken out into the atmosphere and the film surface was observed with an optical microscope (500 times). As a result, it was confirmed that the crystal structure was not observed and the film was in an amorphous state.

  When the obtained substrate was exposed to pure water for 1 minute and observed again with an optical microscope, it was observed that a bleeding pattern was observed and the surface was melted. The substrate was further exposed to pure water for 3 minutes, or the film was wiped with a non-woven fabric soaked with pure water and visually observed. In all cases, the film disappeared.

  Another obtained substrate was exposed to acetone for 1 minute and observed with an optical microscope. As a result, a bleeding pattern was observed and the surface was melted. The substrate was further exposed to acetone for 3 minutes, or the film was wiped with a non-woven fabric containing acetone and then visually confirmed. In all cases, the film was lost.

  Further, the transmittance of the deposited film after film formation was measured in the same manner as in Production Example 1 (C). The results are shown below (Table 1). The transmittance at a wavelength of 320 nm was 6.1%, the transmittance at 360 nm was 35.4%, and it was confirmed that the transmittance was low.

(Synthesis Example 1)
2,7-bis (1,3,2-dioxaborolan-2-yl) -9,9-dioctyl was added to a separable flask equipped with a stirring blade, baffle, length-adjustable nitrogen inlet tube, cooling tube, and thermometer. Fluorene 158. 29 parts by weight of bis- (4-bromophenyl) -4- (1-methylpropyl) -benzenamine 136. 11 parts by weight, 27 parts by weight of tricaprylmethylammonium chloride (Aliquat 336 manufactured by Henkel) and 1800 parts by weight of toluene were charged, and the temperature was raised to 90 ° C. with stirring while flowing nitrogen from the nitrogen introduction tube.

  Next, 0.066 parts by weight of palladium (II) acetate and 0.45 parts by weight of tri (o-toluyl) phosphine were added, and then a 17.5% aqueous sodium carbonate solution (573 parts by weight) was added dropwise over 1 hour. did. After completion of the dropwise addition, the nitrogen inlet tube was lifted from the liquid level and kept under reflux for 7 hours, then 3.6 parts by weight of phenylboric acid was added, kept under reflux for 14 hours, and cooled to room temperature.

  After removing the reaction solution aqueous layer, the reaction solution oil layer was diluted with toluene and washed with 3% acetic acid aqueous solution and ion-exchanged water. To the separated oil layer, 13 parts by weight of sodium N, N-diethyldithiocarbamate trihydrate was added and stirred for 4 hours. Thereafter, the mixture was passed through a mixed column of activated alumina and silica gel, and toluene was passed through to wash the column.

The filtrate and washings were mixed and then added dropwise to methanol to precipitate the polymer. The obtained polymer precipitate was separated by filtration, washed with methanol, and then dried with a vacuum dryer to obtain 192 parts by weight of polymer. The resulting polymer is referred to as polymer compound P1. When the polystyrene equivalent weight average molecular weight and number average molecular weight of this polymer compound P1 were determined by the following GPC analysis method, the polystyrene equivalent weight average molecular weight was 3.7 × 10 ⁵ , and the number average molecular weight was 8.9 ×. There were 10 ⁴ .

(GPC analysis method)
The polystyrene equivalent weight average molecular weight and number average molecular weight were determined by gel permeation chromatography (GPC). Standard polystyrene made by Polymer Laboratories was used to prepare a GPC calibration curve. The polymer to be measured was dissolved in tetrahydrofuran to a concentration of about 0.02% by weight, and 10 μL was injected into the GPC apparatus.

  The GPC apparatus used was LC-10ADvp manufactured by Shimadzu Corporation. As the column, two columns manufactured by Polymer Laboratories (“PLgel” 10 μm MIXED-B column (300 × 7.5 mm)) were connected in series, and tetrahydrofuran was used as a mobile phase at 25 ° C. and 1.0 mL / min. Flowed at a flow rate. The detector used was a UV detector, and the absorbance at 228 nm was measured.

(Production Example 5)
(Production of organic EL element)
Using a glass substrate with an ITO thin film patterned on the surface as a substrate, a 10 nm-thick Al-doped MoO ₃ layer (metal-doped molybdenum oxide layer) is vacuumed on this ITO thin film in the same procedure as in Production Example 1. Vapor deposition was performed.

  After the film formation, the substrate was taken out into the atmosphere, and the polymer compound P1 obtained in Synthesis Example 1 was formed on the deposited film by spin coating to form an interlayer layer having a thickness of 20 nm. The interlayer layer formed on the extraction electrode portion and the sealing area was removed, and baking was performed at 200 ° C. for 20 minutes on a hot plate.

  Thereafter, a polymer light-emitting organic material (manufactured by RP158 Summation Co., Ltd.) was formed on the interlayer layer by a spin coating method to form a light-emitting layer having a thickness of 90 nm. The light emitting layer formed on the extraction electrode portion and the sealing area was removed.

  The subsequent processes up to the sealing were performed in vacuum or nitrogen so that the elements in the process were not exposed to the atmosphere.

  The substrate was heated at a substrate temperature of about 100 ° C. for 60 minutes in a vacuum heating chamber. Thereafter, the substrate was transferred to a vapor deposition chamber, and a cathode mask was aligned on the surface of the light emitting layer so that a cathode was formed on the light emitting portion and the extraction electrode portion. Further, the cathode was deposited while rotating the mask and the substrate. As a cathode, metal Ba is heated by a resistance heating method and deposited at a deposition rate of about 0.2 nm / second and a film thickness of 5 nm, and Al is deposited thereon by an electron beam deposition method at a deposition rate of about 0.2 nm / second. The film was deposited with a film thickness of 150 nm.

Thereafter, the substrate is bonded to a prepared sealing glass coated with UV curable resin around the substrate, kept in vacuum, then returned to atmospheric pressure, fixed by irradiation with UV, and light emitting region Produced a 2 × 2 mm organic EL device.
The obtained organic EL device has a layer structure of glass substrate / ITO film / Al-doped MoO ₃ layer (metal-doped molybdenum oxide layer) / interlayer layer / light emitting layer / Ba layer / Al layer / sealing glass. It was.

(Evaluation of organic EL elements)
The manufactured element was energized so that the luminance was 1000 cd / m ^2, and current-voltage characteristics were measured. In addition, the device was driven at a constant current at 10 mA, light emission was started at an initial luminance of about 2000 cd / m ² , the light emission was continued as it was, and the light emission lifetime was measured. The results are shown in the following (Table 2) and (Table 3). Compared to Comparative Example 2 described later, the maximum power efficiency is slightly higher, the driving voltage at the time of 1000 cd / m ² emission is reduced, and the life is extended by about 1.6 times.

(Production Example 6)
An organic EL element was produced by operating in the same manner as in Production Example 5 except that an Al-doped MoO ₃ layer (metal-doped molybdenum oxide layer) was formed in the same procedure as in Production Example 3, and the current-voltage characteristics and The luminescence lifetime was measured. The emission lifetime was measured by driving at a constant current of 10 mA, starting emission at an initial luminance of about 2000 cd / m ² , and then continuing emission. The results are shown in the following (Table 2) and (Table 3). Compared with Comparative Example 2 below, the maximum power efficiency is slightly higher, the driving voltage at the time of light emission of 1000 cd / m ² is lowered, and the life is extended about 2.4 times.

(Comparative Example 2)
Instead of forming the Al-doped MoO ₃ layer, the same procedure as in Comparative Example 1 was followed, except that the MoO ₃ layer was formed in the same manner as in Production Example 5 to produce an organic EL device, and the current-voltage characteristics The emission lifetime was measured. The light emission lifetime was measured by driving at a constant current of 10 mA, starting light emission at an initial luminance of about 2000 cd / m ² , and continuing light emission as it was. The results are shown in the following (Table 2) and (Table 3).

  In the following Production Example 7, partition walls arranged substantially in parallel are provided, and an organic light emitting ink is used by using a relief printing plate having convex portions corresponding to the concave grooves in the concave grooves (corresponding to the pixel region) between the barrier ribs. The production effect of forming the organic light emitting layer was confirmed.

(Production Example 7)
(Preparation of substrate and formation of anode)
First, an ITO thin film was formed on a transparent glass plate of 200 mm (vertical) × 200 mm (horizontal) × 0.7 mm (thickness), and further patterned to form a striped anode. The repetition interval (pitch) of the anode was 80 μm, and the interval (space width) between the anodes was 10 μm with respect to the anode width (line width) of 70 μm (line / space = 70 μm / 10 μm). The thickness of the anode was 150 nm. A pixel region in which pixels are formed when viewed from one side in the thickness direction of the substrate is set in an island shape at a predetermined interval in the one direction on an ITO thin film extending in one direction.

(Formation of electrical insulation layer)
Next, an insulating film made of SiO ₂ was formed by plasma CVD, and then a plurality of rectangular pixel regions having a width of 50 μm and a length of 150 μm were removed by photolithography and etching to form an electrical insulating layer.

(Formation of partition walls)
Next, using the positive photoresist (trade name “OFPR-800”, manufactured by Tokyo Ohka Kogyo Co., Ltd.) on the entire surface of the substrate, the shape shown in FIGS. 1 and 2 is obtained by conventional photolithography. A partition wall 13a was formed. The formed partition wall 13a had a width dimension of 30 μm and a height dimension of 2 μm. Further, the adjacent dimension between the partition walls 13a was set to 75 μm.

Next, using a vacuum plasma apparatus (trade name “RIE-200L” manufactured by Samco International Co., Ltd.) using CF ₄ gas, the partition wall 13a was subjected to an ink repellency treatment.

(Letterpress printing plate)
A flexographic printing plate (material: polyester resin) having the structure shown in FIG. 3 was prepared corresponding to the partition. The convex portion 21 of the relief printing plate 20 had a height dimension of 100 μm, a width dimension of 30 μm, and a pitch width of 75 μm, and was formed in stripes in the circumferential direction perpendicular to the axial direction Y of the plate cylinder.

(Formation of hole injection layer)
Next, a suspension of poly (3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (manufactured by Bayer, trade name “BaytronP AI4083”) is prepared, and this suspension is filtered through a 0.2 μm membrane filter. did. This filtrate was applied to the pixel region using the relief printing plate. Subsequently, the coating layer was heat-treated at 200 ° C. for 20 minutes to form an 80 nm-thick hole injection layer.

(Formation of light emitting layer)
As organic light emitting materials, polymer light emitting materials of three colors of red, green, and blue (trade names “RP158 (red)”, “GP1300 (green)”, “BP361 (blue)” manufactured by Summation Co., Ltd.)) are respectively used as solvents ( An organic light emitting ink of 3 colors (concentration: 1% by weight) dissolved in anisole / cyclohexylbenzene = a mixed solvent having a weight ratio of 1/1) was prepared.

  Using a flexographic printing plate having stripe-shaped convex portions having the above structure, red organic light-emitting ink was printed on the corresponding pixel region on the substrate and dried to form a red organic light-emitting layer. Similarly, a green organic light emitting ink and a blue organic light emitting ink were sequentially printed and dried to form a green organic light emitting layer and a blue organic light emitting layer. The thickness of the organic light emitting layer of each color was almost the same dimension of 100 nm.

  For printing at this time, “Angstromer SDR-0023 (trade name), plate drum diameter: 80 mm” manufactured by Nissha Printing Co., Ltd. was used as a printing machine. The printing speed was 50 mm / second. Printing was performed in a state in which the plate and the substrate were in contact with each other with a printing push amount of 0 μm, and the plate was pressed from that position by 50 μm (print push amount = 50 μm).

  When the shape of the organic light emitting layer formed in each pixel region was observed with an optical microscope (manufactured by Nikon Corporation, trade name “Optiphoto 88”, objective lens magnification: 50 ×), each organic light emitting layer was separated from the pixel region. It was confirmed that the film was formed in the pixel region without deviation.

(Formation of cathode)
Next, calcium was vapor-deposited with a thickness of 100 mm as a cathode on the light emitting layer, and aluminum was vapor-deposited with a thickness of 2000 mm as an oxidation protective layer. Thus, an organic EL element having a bottom emission structure was produced.

  When the organic light-emitting device obtained as described above was caused to emit light, no blur was observed in multicolor light emission, and a clear multicolor display was obtained.

(Comparative Example 3)
Using a printing plate and printing conditions similar to those of Production Example 7 above, using a substrate provided with partition walls formed in a grid and a relief printing plate having projections corresponding to the pixel regions defined by the partition walls, The organic light emitting ink was printed and dried to form an organic light emitting layer. Other than that was carried out similarly to the said manufacture example 7, and manufactured the organic EL element. The formed partition wall had a height of 2 μm, a width of 50 μm, and a length of 150 μm.

  When the manufactured organic EL element was made to emit light, there was bleeding (mixed color) in color development and display unevenness occurred.

It is a top view of the board | substrate with which the partition was formed. It is a cross-sectional block diagram of the board | substrate seen from the cut surface line II-II of FIG. It is the perspective view which showed the structure of the relief printing plate used for this invention, and the positional relationship with the board | substrate at the time of the printing of the organic light emitting layer using this relief printing plate.

Explanation of symbols

1 Substrate 2 Anode 3 Metal Doped Molybdenum Oxide Layer 13a Partition Wall 13b Electrical Insulating Layer 14 Pixel Region 15 Concave Groove 20 Letterpress Printing Plate 21 Convex Part of Letterpress Printing Plate

Claims (6)

An anode, a cathode, an organic light emitting layer disposed between the anode and the cathode, and a metal-doped molybdenum oxide layer disposed between the anode and the organic light emitting layer, and are placed substantially parallel to each other A method for producing an organic electroluminescence element provided on a support substrate having a plurality of partition walls,
Preparing a substrate having an anode formed on a support substrate having the partition;
A metal-doped molybdenum oxide layer forming step;
An organic light emitting layer forming step of forming an organic light emitting layer by supplying an organic light emitting ink containing an organic light emitting material between the partition walls;
Have
In the organic light emitting layer forming step, the organic light emitting ink is continuously provided along the longitudinal direction of the partition using a relief printing plate having a convex portion corresponding to the concave groove in the concave groove between the plurality of partition walls. and supplied,
The manufacturing method of the organic electroluminescent element characterized by using aluminum as a dopant metal .   The method for manufacturing an organic electroluminescence element according to claim 1, wherein in the metal-doped molybdenum oxide layer forming step, a metal-doped molybdenum oxide layer is formed by simultaneously depositing molybdenum oxide and a dopant metal.   The manufacturing method of the organic electroluminescent element of Claim 1 or 2 which further includes the process of heating the said metal dope molybdenum oxide layer formed in the metal dope molybdenum oxide layer formation process.   The manufacturing method of the organic electroluminescent element of any one of Claims 1-3 which sets the visible light transmittance | permeability of the said metal dope molybdenum oxide layer to 50% or more. Method of manufacturing an organic electroluminescent device according to any one of claims 1 to 4, the proportion of dopant metal contained in the metal doped molybdenum oxide layer, a 0.1~20.0mol%. The relief printing plate is a cylindrical or columnar, the so that the longitudinal direction a plurality of convex portions overlaps the circumferential direction, according to claim 1-5, characterized by arranging the convex portions of several plurality The manufacturing method of the organic electroluminescent element of any one of these.

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