JP2017139062A - Method for manufacturing electrode for organic el device, and method for manufacturing organic el device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic EL device which never induces a short circuit in the device, and which enables the achievement of a higher light-extraction efficiency.SOLUTION: A method for manufacturing an electrode for an organic EL device comprises the steps of: coating a support substrate with an active energy ray-curable composition arranged by mixing organic particles A, inorganic particles B smaller than the organic particles A, and an active energy ray-curable component C and then, drying the coated active energy ray-curable composition to form an active energy ray-curable film X of a particular thickness; then, irradiating the film with active energy rays to form a cured film Y; heating the film to destroy part of a convex portion on a surface of the cured film Y to form a concave portion, thereby obtaining a cured film Z; and depositing metal on the hardened film Z.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing an electrode for an organic EL element, and a method for producing an organic EL element.

Organic electroluminescence elements (hereinafter referred to as organic EL elements) are used as self-luminous elements as video display devices such as displays and as surface light sources. Such an organic EL element is generally a translucent electrode as an anode on a translucent support substrate such as a glass substrate or a transparent plastic film, an organic layer including a light emitting layer, and a cathode. It is manufactured by sequentially laminating metal electrodes. The organic layer including the light emitting layer includes a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer. The hole injection layer is located on the translucent electrode (anode) side, and the electron injection layer is located on the cathode (metal electrode) side.
Due to the voltage applied between the translucent electrode and the metal electrode, the electrons supplied from the cathode and the holes supplied from the anode are recombined in the organic layer, and the excitons generated thereby are excited. EL light is emitted when transitioning from a state to a ground state. The light emitted from the EL is transmitted through the transparent electrode and taken out from the transparent support substrate side.

  However, such an organic EL element has a problem that light generated in the organic layer including the light emitting layer cannot be sufficiently extracted to the outside. That is, most of the light generated in the organic layer including the light-emitting layer disappears due to heat while repeating multiple reflections inside the element, or is guided from the end of the element through the inside of the element. Since the light is emitted, there is a problem that sufficient external extraction efficiency cannot be achieved. Therefore, in recent years, in the field of organic EL elements, it has been proposed to improve the efficiency of extracting light to the outside by using the diffraction effect by the electrode having the concavo-convex shape.

A metal fine particle layer in which metal fine particles are dispersed inside the dielectric layer is provided between the light emitting layer and the electron transport layer, or between the light emitting layer and the hole transport layer, and light from the light emitting layer passes through the metal fine particle layer. A technology has been devised that excites plasmon resonance when propagating and takes out light outside with high efficiency (Patent Document 1).
In addition, a technique for improving luminous efficiency by utilizing surface plasmon resonance by a periodic grating structure is disclosed (Patent Documents 2 to 9).

  In these prior documents, photolithography, electron beam lithography, mechanical cutting, laser processing, two-beam interference exposure, reduced exposure, and the like are used as methods for producing a periodic grating structure. However, except for two-beam interference exposure, these methods are not suitable for producing a periodic grating structure in a large area, and thus are limited in terms of industrial use. In addition, periodic grating structure fabrication by two-beam interference exposure can also be fabricated to a certain large area, but in the case of a large area with a side of several centimeters or more, vibration, wind, thermal contraction / expansion of the entire optical setup, It is extremely difficult to produce a uniform and accurate periodic grating structure due to various disturbance factors such as fluctuations, voltage fluctuations, and the like. In addition, the production of a periodic grating structure by a dry etching method using a particle monolayer film as an etching mask also has a problem that a monolayer film production apparatus and an etching apparatus are indispensable, resulting in a large area and low cost productivity.

JP 2007-35430 A JP 2002-270891 A Special Table 2005-535121 JP 2005-108982 A JP 2006-259064 A Japanese Patent Laid-Open No. 2004-31350 JP 2006-313667 A JP 2009-158478 A Japanese Patent Application No. 2013-522947

  The present invention has been made in view of the above-described problems of the prior art, and provides an organic EL device capable of achieving higher light extraction efficiency without inducing a short circuit in the device. For the purpose.

As a result of intensive studies to solve the above problems, the present inventors have reached the present invention.
That is, this invention is a manufacturing method of the electrode for organic EL elements containing following process (1)-(5).
(1) An average particle size of the dispersion is 100 to 500 nm, and a dispersion of organic particles A having a coefficient of variation of 30% or less, a dispersion of inorganic particles B, and an active energy ray-curable component C are mixed. An active energy ray-curable composition, wherein the average particle size of the organic particles A in the dispersion of the organic particles A is larger than the average particle size of the inorganic particles B in the dispersion of the inorganic particles B A step of preparing a linear curable composition.
(2) The active energy ray-curable film X, which is coated with the active energy ray-curable composition on a support substrate and then dried and has convex portions due to the organic particles A on the surface, the organic particles A step of forming an active energy ray-curable film X having a thickness of 2 to 20 times the average particle diameter of the organic particles A in the dispersion of A.
(3) A step of irradiating the active energy ray-curable film X with active energy rays to form a cured film Y.
(4) Next, the surface of the cured film Y is heated to break the convex portions so as to leave the ridges, and the concave portions are formed, and the proportion of the concaves and convexes with an interval of 200 to 450 nm is 30% or more. A step of obtaining a cured film Z.
(5) A step of depositing a metal on the cured film Z.

  It is a manufacturing method of the element electrode for organic EL of Claim 1 whose average height of the unevenness | corrugation of the cured film Z is 10-100 nm.

  The manufacturing method of the element electrode for organic EL of Claim 1 or 2 whose average particle diameter of the dispersion | distribution of the inorganic particle B is 5-50 nm.

Moreover, this invention relates to the manufacturing method of the organic EL element containing following process (1)-(8).
(1) An average particle size of the dispersion is 100 to 500 nm, and a dispersion of organic particles A having a coefficient of variation of 30% or less, a dispersion of inorganic particles B, and an active energy ray-curable component C are mixed. An active energy ray-curable composition, wherein the average particle size of the organic particles A in the dispersion of the organic particles A is larger than the average particle size of the inorganic particles B in the dispersion of the inorganic particles B A step of preparing a linear curable composition.
(2) The active energy ray-curable film X, which is coated with the active energy ray-curable composition on a support substrate and then dried and has convex portions due to the organic particles A on the surface, the organic particles A step of forming an active energy ray-curable film X having a thickness of 2 to 20 times the average particle diameter of the organic particles A in the dispersion of A.
(3) A step of irradiating the active energy ray-curable film X with active energy rays to form a cured film Y.
(4) Next, the surface of the cured film Y is heated to break the convex portions so as to leave the ridges, and the concave portions are formed, and the proportion of the concaves and convexes with an interval of 200 to 450 nm is 30% or more. A step of obtaining a cured film Z.
(5) A step of manufacturing a device electrode for organic EL by depositing a metal on the cured film Z.
(6) A step of forming an organic layer including a light emitting layer on the organic EL electrode.
(7) A step of forming a transparent electrode on the organic layer including the light emitting layer.
(8) The process of sticking on a transparent support substrate on the said transparent electrode using an adhesive agent.

  According to the present invention, an electrode for providing an organic EL device capable of achieving higher light extraction efficiency without inducing a short circuit in the device can be obtained by a simple method.

  Embodiments of the present invention will be described in detail below, but the description of the constituent elements described below is an example (representative example) of an embodiment of the present invention, and the present invention does not exceed the gist thereof. Not specific to the content.

<Organic particle A>
The organic particles A will be described.
As the organic particles A, polyacrylate beads, polymethacrylate beads, acrylic-styrene copolymer beads, melamine resin beads, polycarbonate beads, crosslinked polystyrene beads, polyvinyl chloride beads, benzoguanamine-melamine formaldehyde condensate beads, and the like are used. However, it is not necessarily limited to these.

  The organic particles A can be obtained by various methods, and can be obtained in a dispersion state. Examples thereof include emulsion polymerization (one embodiment of which is soap-free emulsion polymerization), dispersion polymerization, suspension polymerization, seed polymerization and the like. Among these, emulsion polymerization and dispersion polymerization are preferable because they have a relatively narrow particle size distribution and contribute to the reduction of wavelength dependency in the present invention. Moreover, the dispersibility by steric repulsion can be provided by setting it as the polymer containing various (meth) acrylates.

  It is important that the average particle size of the dispersion of organic particles A obtained as described above is larger than the average particle size of the inorganic particles B in the dispersion of inorganic particles B described later. Specifically, the average particle size of the dispersion of organic particles A is preferably 100 to 500 nm. The uneven shape of the cured film Z to be described later can be controlled by the average particle diameter of the dispersion of organic particles A. By setting the average particle diameter of the dispersion of organic particles A to 100 nm or more, the uneven average interval with respect to the visible light wavelength can be controlled, and by setting the average particle diameter to 500 nm or less, a diffraction angle necessary for the diffraction effect can be secured. it can. Preferably, it is 100 nm-450 nm, More preferably, it is 150 nm-370 nm.

In the present specification, the “average particle size” of the dispersion of organic particles A is a dispersed particle size in consideration of the particle size of secondary particles due to aggregation, unlike the average primary particle size described later. This can be determined by the dynamic light scattering method. Here, even if the organic particles A having the same average primary particle size are used, the average primary particle size and the particle size distribution are different depending on the dispersion state of the organic particles A. Because there is.
“Average particle size” is the value of the dispersed particle size at 50% by volume of the measurement sample. These can be measured by “Nanotrack UPA” manufactured by Nikkiso Co., Ltd. in the dynamic light scattering method.

As the particle size distribution of the organic particles A, the coefficient of variation is preferably 30% or less. The “variation coefficient” is expressed as a percentage of a value obtained by dividing the standard deviation of the particle diameter by the average particle diameter, and is an index of the degree of variation with respect to the average particle diameter.
If the coefficient of variation is larger than 30%, the variation in particle size increases, and a predetermined uneven shape may not be obtained. More preferably, the coefficient of variation is 20% or less.

  As the dispersion of the organic particles A, a dispersion liquid previously dispersed in a solvent is preferably used. At that time, an additive such as a surfactant for stabilizing the dispersion may be added.

<Inorganic particles B>
The curable film X, the cured film Y, and the cured film Z include inorganic particles B. It is desirable that the inorganic particles B do not aggregate with the organic particles A and are uniformly dispersed in the active energy ray-curable composition, the curable film X, the cured film Y, and the cured film Z.
When forming the cured film Z, the inorganic particles B have a function of promoting the destruction and decomposition of the organic particles A located in the vicinity of the surface.
Specifically, as the inorganic particles B, titanium oxide (TiO ₂ ), zirconium oxide (ZrO ₂ ), cerium oxide (CeO ₂ ), hafnium oxide (HfO ₂ ), niobium pentoxide (Nb ₂ O ₅ ), five From at least one material selected from the group consisting of tantalum oxide (Ta ₂ O ₅ ), indium oxide (In ₂ O ₃ ), tin oxide (SnO ₂ ), indium tin oxide (ITO), and zinc oxide (ZnO). Particles, but not necessarily limited to these.
Titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ) are particularly preferable from the viewpoint of dispersibility.

In order to form predetermined irregularities on the cured film Z, it is preferable that there is no strong aggregation between the inorganic particles B. Therefore, the average primary particle diameter of the inorganic particles B is preferably 100 nm or less, more preferably 5 to 50 nm.
The “average primary particle diameter” in the present specification means an individual particle diameter not taking aggregation into account, and is, for example, 50 actually measured using a transmission electron microscope (TEM) or a scanning electron microscope (SEM). It is the average value of the particle diameter.

  As the inorganic particles B, powder can be used as it is, but it is preferable to use a dispersion previously dispersed in a solvent. The average particle size of the dispersion of inorganic particles B is preferably 5 to 50 nm.

The dispersing method is preferably a method using a dispersing machine using a dispersing agent that matches the surface state of the inorganic particles B. Dispersers include paint conditioner (manufactured by Red Devil), ball mill, sand mill (such as “Dyno mill” manufactured by Shinmaru Enterprises), attritor, pearl mill (such as “DCP mill” manufactured by Eirich), coball mill, homomixer, Homogenizers (such as “Clairemix” manufactured by M Technique Co., Ltd.), wet jet mills (“Genus PY” manufactured by Genus, “Nanomizer” manufactured by Nanomizer), microbead mills (“Super Apeck Mill” manufactured by Kotobuki Industries Co., Ltd.) And “Ultra Apeck Mill”), an ultrasonic disperser, and the like.
When media are used in the disperser, glass beads, zirconia beads, alumina beads, magnetic beads, polystyrene beads, and the like are preferably used.
Regarding dispersion, two or more types of dispersers or two or more types of media having different sizes may be used and may be implemented step by step.

  In order to disperse the inorganic particles B, a dispersant can be added as necessary. The dispersant is not particularly limited as long as it suppresses the aggregation of the inorganic particles B and improves the dispersibility. Preferably, a low molecular weight dispersant, a high molecular weight dispersant, and a surfactant type dispersant are suitably used.

<Active energy ray-curable component C>
As the component having active energy ray curability, those having an ethylenically unsaturated double bond are preferable. Examples of the ethylenically unsaturated double bond include (meth) acrylate groups and unsaturated groups such as maleimide groups. The component having active energy ray curability can also have an epoxy group, an oxetanyl group, and the like.
By curing the component having active energy ray curability, the organic particles A or the inorganic particles B can be held in the cured film. The component having active energy ray curability preferably has a mass average molecular weight (Mw) of 5,000 to 20,000. When the mass average molecular weight (Mw) is 5000 or more, the organic particles A or the inorganic particles B can be favorably dispersed. Further, when the mass average molecular weight (Mw) is 20000 or less, the viscosity can be reduced, and aggregation of the organic particles A or inorganic particles B can be suppressed / prevented, and a curable film X having excellent flatness can be obtained.

  When the component having active energy ray curability contains an ethylenically unsaturated double bond, the double bond equivalent is preferably 400 (g / mol) to 1600 (g / mol). When the double bond equivalent is 400 (g / mol) or more, curing shrinkage of the cured film can be suppressed, and a fine crack or peeling is hardly generated in the translucent electrode. On the other hand, when the double bond equivalent is 1600 (g / mol) or less, the crosslinking density increases, and peeling of the electrode in the cleaning step can be suppressed / prevented.

There is no restriction | limiting in particular as a method of obtaining the component which has an ethylenically unsaturated double bond.
For example, an unsaturated monomer component containing an ethylenically unsaturated monomer having one or more functional groups selected from a hydroxyl group, an epoxy group, an acid (carboxyl) group, and an isocyanate group is polymerized. And a method of modifying the functional group in the copolymer with an ethylenically unsaturated monomer having a functional group capable of reacting with the functional group and an ethylenically unsaturated double bond.
The combination of the functional group of the copolymer and the functional group of the ethylenically unsaturated monomer used for modification is not particularly limited. For example, a hydroxyl group and an isocyanate group, a hydroxyl group and an epoxy group, and an epoxy group and an acid (carboxyl) ) Group and the like.

  Moreover, it is preferable that the component C which has active energy ray curability has a heat crosslinkable group as a crosslinkable group other than an ethylenically unsaturated double bond. Thermally crosslinkable functional groups include hydroxyl groups, epoxy groups, oxetanyl groups, acid (carboxyl) groups, and isocyanate groups. These can be used alone or in combination of two or more.

<Active energy ray-curable composition>, <Active energy ray-curable film X>
The active energy ray-curable composition is prepared by independently preparing a dispersion of organic particles A and a dispersion of inorganic particles B, and then mixing or kneading the component C having active energy ray curability. Can be obtained.
From the viewpoint of dispersion stability, after mixing the dispersion of the organic particles A and the dispersion of the inorganic particles B, the component C having active energy ray curability and, if necessary, other components are uniformly mixed. A method of mixing is preferred.
The active energy ray-curable composition may be a silane compound, an ultraviolet absorber, an antioxidant, a heat stabilizer, a light stabilizer, an antistatic agent, a surfactant, a storage stabilizer, a leveling agent, Light stabilizers and the like can also be included.

The active energy ray curable film X is applied to a support substrate with an active energy ray curable composition containing a dispersion of organic particles A, a dispersion of inorganic particles B, and a component C having active energy ray curable properties. Obtained by drying. Hereinafter, the active energy ray-curable film X may be abbreviated as the curable film X. It is important that the thickness of the curable film X is 2 to 20 times the average particle diameter of the organic particles A in the dispersion of the organic particles A, and preferably 2 to 10 times.
The curable film X can contain a photopolymerization initiator in addition to the organic particles A, the inorganic particles B, and the component C having active energy ray curability.

The curable film X comprises the organic particles A, the inorganic particles B, and the active energy ray-curable component C in a total of 100% by mass, the organic particles A being 1 to 35% by mass, and the inorganic particles B being 30 to 75% by mass. The active energy ray-curable component C is preferably contained in an amount of 1 to 35% by mass, the organic particles A in an amount of 10 to 35% by mass, the inorganic particles B in an amount of 35 to 75% by mass, and the active energy ray curable component C in an amount of 5 to 30%. More preferably, the organic particle A contains 15 to 30% by mass, the inorganic particle B contains 40 to 70% by mass, and the active energy ray-curable component C contains 5 to 30% by mass.
The amount of the organic particles A is preferably in the above range in that a predetermined uneven shape is expressed on the surfaces of the curable film X and the cured film Y. The amount of the inorganic particles B is important in terms of suppressing aggregation of the particles and ensuring the strength of the uneven shape to be formed, and is preferably in the above range. The amount of the active energy ray-curable component C is preferably in the above range from the viewpoint of improving the stability and operability of the active energy ray-curable cured film X.

As a method of applying the active energy ray-curable composition to the support substrate, a known method can be used,
For example using lots or wire bars;
In addition, various coating methods such as micro gravure coating, gravure coating, die coating, curtain coating, lip coating, slot coating or spin coating can be used.
In the case of patterning, 1) a method of directly patterning by a printing method and 2) a method of patterning by a photolithography method can be used.
1) The printing method can be performed by a normal printing method such as flexographic printing, gravure printing, gravure offset printing, offset printing, reverse offset printing, screen printing, letterpress printing, and ink jet printing.
2) In the photolithography method, a photosensitive active energy ray-curable composition is used. In that case, the active energy ray-curable composition is directly applied to the substrate and dried, or after coating the composition dissolved in a solvent on a film substrate (hereinafter referred to as a separate film), the solvent is dried. After bonding the photosensitive dry film obtained by the step to a light-transmitting substrate, the active energy ray-curable cured film X was formed by performing adhesion or removal of bubbles and the like by lamination or vacuum lamination. Later, pattern formation is performed by solution development or alkali development.

<Curing film Y>
By irradiating the active energy ray-curable film X with active energy rays, the cured film Y can be formed.
By curing with active energy rays, the uneven shape on the surface of the curable film X can be fixed. The active energy rays can be used in combination of one or two or more selected from light (electromagnetic wave) curability by visible light, ultraviolet rays, infrared rays, and the like, and electron beam irradiation.

The surfaces of the curable film X and the cured film Y have irregularities. The average height of the irregularities is preferably 10 to 200 nm, and more preferably 20 to 150 nm.
“Average height of unevenness” and “interval of unevenness” on the surfaces of the curable film X and the cured film Y are measured with a scanning probe microscope (for example, product name “Asylum Research MFP-3D” manufactured by Oxford Instruments). Etc.). That is, the average of the absolute values of the altitudes (Yp) of the highest peak to the tenth peak measured from the average line of the extracted part in the vertical direction from the roughness line by a reference length of 5 μm. The sum of the value and the average value of the absolute values of the altitude (Yv) of the bottom valley from the lowest valley bottom to the tenth valley is called “average height of unevenness”.

  Moreover, the uneven | corrugated space | interval distribution state of the surface of the curable film X and the cured film Y can be calculated | required using the same apparatus. For example, with respect to a 2.0 μm × 2.0 μm region, the interval between adjacent convex portions or adjacent concave portions can be measured, and the interval distribution state of the unevenness can be obtained from the distribution. In the distribution of the unevenness on the surfaces of the curable film X and the cured film Y in the present invention, the proportion of the unevenness with an interval of 200 to 450 nm is preferably 10% or more, and more preferably 20% or more.

<Curing film Z>
By heating and curing the cured film Y, at least a part of the organic particles A in the vicinity of the cured film Y surface is destroyed and decomposed so as to leave the ridges of the protrusions on the surface of the cured film Y. Can be obtained. For example, when the temperature is raised at 10 ° C./minute, the heating time of the cured film Y at a temperature at which the mass of the organic particles A is reduced by 5 to 10% is the distance between the unevenness and the depth of the cured film Z It can heat on the conditions used as the range mentioned later.

  For example, the heating conditions for breaking the convex portions of the organic particles A and forming the concave portions can be controlled by temperature and time. The heating temperature is preferably 200 to 300 ° C. By making it 200 degreeC or more, it can be decomposed | disassembled gradually, and by making it 300 degreeC or less, a decomposition rate can be controlled arbitrarily. More preferably, it is 210 degreeC-280 degreeC, More preferably, it is 220-250 degreeC. The heating time is preferably 5 to 60 minutes. By setting it to 5 minutes or more, the decomposition rate can be arbitrarily controlled, and by setting it to 60 minutes or less, the shape of the recess can be maintained and controlled to a predetermined uneven shape. Preferably it is 10-50 minutes, More preferably, it is 20-40 minutes.

As in the case of the curable film X and the cured film Y, the average height of the unevenness of the cured film Z and the interval distribution state of the unevenness can be obtained.
The average height of the unevenness of the cured film Z is preferably 10 to 100 nm. When the thickness is 10 nm or more, the diffraction effect with respect to the visible light wavelength can be secured, and when the thickness is 100 nm or less, the above-described non-uniform electric field distribution can be suppressed, and heat generation and element destruction due to electric field concentration can be prevented. The average height is more preferably 20 to 90 nm, further preferably 30 to 80 nm, and further preferably 40 to 60 nm.
In the unevenness distribution of the cured film Z, the proportion of the unevenness with an interval of 200 to 450 nm is preferably 30% or more, and more preferably 40% or more.
By setting the unevenness on the surface of the cured film Z to such a depth and interval, similar unevenness can be formed on the surface of the electrode for an organic EL element in which a metal is vapor-deposited on the cured film Z. As a result, the energy of light lost as surface plasmons is extracted by the concavo-convex structure, and the extracted energy can be emitted from the surface of the metal layer as radiation light.

[Electrode for organic EL element], [Organic EL element]
The electrode for an organic EL element can be obtained by vapor-depositing a metal on the cured film Z.
And an organic EL element forms the organic layer containing a light emitting layer on the said electrode for organic EL elements, then forms a transparent electrode on the organic layer containing the said light emitting layer, and also uses the adhesive agent, It can be obtained by pasting on a transparent support substrate on a transparent electrode.
As the metal used for vapor deposition and the vapor deposition method, a known metal and a known method can be used.
For the organic layer including the light emitting layer, the transparent electrode, the adhesive, and the transparent support substrate, similarly, a known material and a known production method can be appropriately selected.

The surface of the electrode for organic EL elements can have the same unevenness as that of the cured film Z on the surface. In the organic EL element, near-field light is generated in the very vicinity when the light emitting layer emits light. Since the distance between the light emitting layer and the metal layer is very short, the near-field light is converted into propagation-type surface plasmon energy on the surface of the metal layer. As a result, high-intensity light is emitted from the extraction surface, and the extraction efficiency is improved.
In this invention, the periodicity of the unevenness | corrugation of the surface of the electrode for organic EL elements is low, and a recessed part or a convex part is distributed at random. This randomness of the uneven shape contributes to the improvement of broadband light extraction efficiency.

  EXAMPLES The present invention will be described more specifically with reference to the following examples. However, the following examples do not limit the scope of rights of the present invention. Unless otherwise specified, “part” represents “part by mass” and “%” represents mass%.

  First, the dispersion particle diameter of the organic particles A and the inorganic particles B, the measurement method of the heating conditions for obtaining the cured film Z, and the measurement method of the uneven shape will be described.

(Dispersed particle size)
The dispersed particle size was measured using “Nanotrack UPA” manufactured by Nikkiso Co., Ltd.
The sample cell was filled with a dispersion medium used for organic particles A or inorganic particles B, and a blank was measured. Next, organic particle A dispersion liquid or inorganic particle B was added thereto and diluted to a measurable concentration range. The measurement by the dynamic light scattering method was performed, and the value of the dispersed particle size at 50% by volume of the measurement sample was defined as the particle size. Further, among the dispersed particle diameters, the volume% of the particle diameter of 600 nm or more was defined as the content of particles having a particle diameter of 600 nm or more.

(Temperature conditions for obtaining the cured film Z)
The heating conditions (temperature, time) for obtaining the cured film Z were measured by the following method. Using a differential thermal and thermal mass measuring device EXSTER TG / DTA6300 manufactured by Seiko Instruments Inc., the mass of the organic particles A is reduced by 5% under an air stream of 200 ml / min at a heating rate of 10 ° C./min. Then, a temperature of 95% before temperature increase was obtained.

(Measurement of film thickness of curable film X and cured films Y and Z)
The film thicknesses of the curable film X and the cured films Y and Z were measured by the following method. Using a contact type film thickness meter “Digi Micro Counter TC-101” manufactured by Nikon Corporation, an average value of 10 or more measured values was defined as a film thickness.

(Measurement of irregularities on the surfaces of the curable film X and the cured films Y and Z)
Measurement was performed using a product name “Asylum Research MFP-3D” manufactured by Oxford Instruments.
Cantilever material: Silicon Measurement environment temperature: 25 ° C
Measurement area: 2 μm × 2 μm

(1) Preparation of dispersion of organic particles A
(Production Example 101)
Under N ₂ atmosphere, 50 g of trifluoroethyl methacrylate, 40 g of methyl methacrylate, 5 g of allyl methacrylate, and 5 g of isobornyl acrylate were added to 566.7 g of water and stirred vigorously. An aqueous solution in which 0.167 g of '-azobis (2-amidinopropane) dihydrochloride (hereinafter referred to as “V-50”) was dissolved in a very small amount of water was added at once and polymerized at 80 ° C. for 8 hours. After the polymerization, methoxypropyl acetate was added, water was removed by stripping, and an organic particle A dispersion (A-1) (acrylic resin particle dispersion) adjusted to a solid content of 20% by mass was produced.
The average particle diameter of the organic particles A in the obtained organic particle A dispersion (A-1) was 290 nm, and the coefficient of variation was 5%.
The organic particle A dispersion (A-1) was dried to obtain organic particles A. The 5% thermal decomposition temperature was determined to be 230 ° C.

(Production Example 102)
Polymerization and stripping were carried out in the same composition as in Production Example 101 except that the amount of water was changed to 900 g to produce an organic particle A dispersion (A-2) (acrylic resin particle dispersion) having a solid content of 20% by mass. did.
The average particle diameter of the organic particles A in the obtained organic particle A dispersion (A-2) was 120 nm, and the coefficient of variation was 5%.
The organic particle A dispersion (A-2) was dried to obtain organic particles A. The 5% thermal decomposition temperature was determined to be 230 ° C.

(Production Example 103)
Under N ₂ atmosphere, 50 g of trifluoroethyl methacrylate, 40 g of methyl methacrylate, 5 g of allyl methacrylate, and 5 g of isobornyl metallate were added to a mixed solvent of 365 g of methanol and 201.7 g of water, and the mixture was vigorously stirred and heated to 60 ° C. Then, an aqueous solution in which 0.167 g of “V-50” was dissolved in a very small amount of water was added all at once and polymerized at 60 ° C. for 8 hours. After the polymerization, methoxypropyl acetate was added, and methanol and water were removed by stripping to prepare an organic particle A dispersion (A-3) (acrylic resin particle dispersion) adjusted to a solid content of 20% by mass.
The average particle diameter of the organic particles A in the obtained organic particle A dispersion (A-3) was 420 nm, and the variation coefficient was 11%.
The organic particle A dispersion (A-3) was dried to obtain organic particles A. The 5% thermal decomposition temperature was determined to be 230 ° C.

(Production Example 104)
Under a N ₂ atmosphere, 50 g of trifluoroethyl methacrylate, 45 g of methyl methacrylate, and 5 g of allyl methacrylate were added to a mixed solvent of 409.2 g of methanol and 157.5 g of water and stirred vigorously. An aqueous solution in which 0.167 g was dissolved in a very small amount of water was added all at once and polymerized at 40 ° C. for 8 hours. After polymerization, methoxypropyl acetate was added, methanol and water were removed by stripping, and an organic particle A dispersion (A-4) (acrylic resin particle dispersion) adjusted to a solid content of 20% by mass was produced.
The average particle diameter of the organic particles A in the obtained organic particle A dispersion (A-4) was 588 nm, and the coefficient of variation was 15%.
The organic particle A dispersion (A-4) was dried to obtain organic particles A. The 5% thermal decomposition temperature was determined to be 230 ° C.

(Production Example 105)
Polymerization and stripping were carried out with the same composition as in Production Example 101 except that 0.167 g of “V-50” dissolved in a very small amount of water was gradually added dropwise over 1 hour, and the solid content was 20% by mass. Organic particle A dispersion liquid (A-5) (acrylic resin particle dispersion liquid) was prepared.
The average particle diameter of the organic particles A in the obtained organic particle A dispersion (A-5) was 340 nm, and the variation coefficient was 40%.
The organic particle A dispersion (A-5) was dried to obtain organic particles A. The 5% thermal decomposition temperature was 230 ° C.

(Production Example 106)
Advancel NS (manufactured by Sekisui Chemical Co., Ltd.), which is a commercially available organic particle, was added to methoxypropyl acetate to obtain an organic particle A dispersion (A-6) adjusted to a solid content of 20% by mass. The average particle diameter of the organic particles A in the obtained organic particle A dispersion (A-6) was 150 nm, and the coefficient of variation was 13%.
The organic particle A dispersion (A-6) was dried to obtain organic particles A. The 5% thermal decomposition temperature was determined to be 230 ° C.

(Production Example 107)
Commercially available organic particles Tuftic F-120 (Toyobo Co., Ltd.) was added to methoxypropyl acetate to obtain an organic particle A dispersion (A-7) adjusted to a solid content of 20% by mass. The average particle diameter of organic particles A in the obtained organic particle A dispersion (A-7) was 200 nm, and the coefficient of variation was 10%.
The organic particle A dispersion (A-7) was dried to obtain organic particles A. The 5% thermal decomposition temperature was 230 ° C.

(2) Preparation of dispersant
A 4-necked flask equipped with a stirrer, reflux condenser, dry air inlet tube, thermometer, 80.0 parts biphenyltetracarboxylic dianhydride, 250.0 parts pentaerythritol triacrylate, 0.24 parts methylhydroquinone, cyclohexanone 217.83 parts were added and the temperature was raised to 85 ° C. Next, 1,8-diazabicyclo [5.4.0] -7-undecene as a catalyst 65 parts was added and reacted at 90 ° C. for 8 hours. Subsequently, 134.3 parts of lauryl glycidyl ether, 86.9 parts of cyclohexanone, and 2.82 parts of dimethylbenzylamine were added to the solution, and the temperature was gradually raised and reacted at 100 degrees. The mixture was cooled to room temperature to obtain a dispersant solution having a solid content of 60% by mass. The weight average molecular weight (Mw) was 3,500.

(3) Preparation of Dispersion of Inorganic Particle B Dispersant solution 3 obtained from 106.7 g of titanium oxide (TiO ₂ ) fine particles having an average primary particle diameter of 15 nm and 86.7 g of methoxypropyl acetate as a dispersion medium, (2) .3 g (containing about 1.98 g of dispersant) was added. A two-stage dispersion treatment was performed on the obtained liquid. As pre-dispersion, zirconia beads (average diameter: 1.25 mm) were used as media and dispersed for 1 hour with a paint shaker. As this dispersion, zirconia beads (average diameter: 0.1 mm) were used as media, and the dispersion was carried out for 7 hours with a disperser UAM-015 manufactured by Kotobuki Industries Co., Ltd. As described above, an inorganic particle B dispersion (titanium oxide fine particle dispersion) was produced. The average particle diameter of the titanium oxide fine particles in the dispersion was 50 nm. The dispersion contains 50% non-volatile components, titanium oxide contained in 100% non-volatile components is about 83.5%, and the dispersant is 16.5%.

(4) Production of active energy ray-curable component 100 parts of methoxypropyl acetate as a solvent was placed in a reaction vessel equipped with a stirrer, a thermometer, a dropping device, a reflux condenser, and a gas introduction tube. The container was heated to 80 ° C. while injecting nitrogen gas. While maintaining this temperature, a mixture of 24 parts of dicyclopentanyl methacrylate, 15 parts of hydroxyethyl methacrylate, 36.6 parts of methacrylic acid, and 3 parts of 2,2′-azobisisobutyronitrile was added dropwise over 1 hour. The polymerization reaction was carried out. After completion of the dropwise addition, the mixture was further reacted at 80 ° C. for 3 hours, and then 0.5 parts of azobisisobutyronitrile dissolved in 40 parts of methoxypropyl acetate was added, and then stirring was continued for 3 hours at the same temperature. Thus, a copolymer was obtained.
Next, dry air was introduced into the reaction vessel, charged with 30 parts of glycidyl methacrylate (GMA), 37 parts of methoxypropyl acetate, 0.6 part of dimethylbenzylamine, and 0.1 part of methoquinone, and then at the same temperature for 10 hours. Stirring was continued. After cooling to room temperature, a solution of an active energy ray-curable component having a solid content of 35% by mass was obtained by dilution with methoxypropyl acetate. The active energy ray-curable component had a 5% thermal decomposition temperature of 230 ° C. or higher, a mass average molecular weight (Mw) of 15000, and a double bond equivalent of 500.

Example 1
(5) Preparation of active energy ray-curable composition Organic particle A: inorganic particle B: active energy ray-curable component: photopolymerization initiator: silane coupling agent: leveling agent mass ratio is 20: 60.1: 8 After mixing the organic particle A dispersion (A-1), the inorganic particle B dispersion, the solution of the active energy ray curable component, and the like so as to be 2: 0.6: 11: 0.1. The mixture was filtered through a filter having a mesh diameter of 5 μm to prepare an active energy ray curable composition.

(6) Production of active energy ray-curable film X Using a spin coater, the active energy ray-curable composition is applied to a 100 mm × 100 mm, 0.7 mm thick glass substrate (Corning glass “Eagle 2000”). After coating and holding on a hot plate heated to 110 ° C. for 2 minutes, it was allowed to cool to produce an active energy ray-curable film X having a thickness of 1.3 μm.

(7) Production of cured film Y Next, the cured film Y was irradiated with ultraviolet rays having illuminances of 20 mW / cm ² and 200 mJ / cm ² using an ultrahigh pressure mercury lamp.

(8) Production of Cured Film Z Next, the cured film Y was placed in an oven heated to 230 ° C. and left for 20 minutes. Then, the cured film Z was obtained by standing to cool at room temperature.

(9) Preparation of electrode for organic EL element After vapor-depositing Mg and Ag on the cured film Z to form a MgAg layer having a thickness of 100 nm, from the viewpoint of preventing MgAg oxidation, Ag was deposited thereon to a thickness of 50 nm to form a back electrode (cathode) for an organic EL device.

(10) Production of Organic EL Element A 30 nm thick electron injection layer ([Alq3] shown in Table 2) is formed on the organic EL element electrode, and a 40 nm thick red color is formed on the electron injection layer. The light emitting layer (see Table 2) was formed.
Next, N, N′-di- (1-naphthyl) -N, N′-diphenylbenzine (hereinafter referred to as α-NPD) is formed to a thickness of 50 nm as a hole transport layer on the red light emitting layer. On the hole transport layer, copper phthalocyanine (hereinafter referred to as CuPc) was formed to a thickness of 15 nm as a hole injection layer.
Thereafter, an ITO ceramic target (In ₂ O ₃ : SnO ₂ = 90: 10 (mass ratio)) was used to form an ITO film having a thickness of 150 nm on the hole injection layer by DC sputtering. The ITO film was etched using a photoresist to form a pattern so that the light emission area was 5 mm × 5 mm. After ultrasonic cleaning, ozone cleaning was performed using a low-pressure ultraviolet lamp to obtain a transparent electrode (anode).
Thereafter, an ultraviolet curable epoxy resin was dropped, and a slide glass was placed thereon as a transparent support substrate, and the epoxy resin was cured using a high-pressure ultraviolet lamp to obtain a red organic EL device element.
In the same manner as described above, a light emitting layer and an electron injection layer shown in Table 2 were used to produce blue, green, and white light emitting elements, respectively, thereby obtaining organic EL elements.

(11) Evaluation The light extraction efficiency, the light emission appearance, and the wavelength dependency of the obtained organic EL element were evaluated based on the following criteria.
<< light extraction efficiency >>
Front luminance of organic EL element produced by glass substrate without forming cured film Z by using Konica Minolta Sensing Co., Ltd. spectral radiance meter “CS-2000” Was measured respectively.
Based on the case where the cured film Z was not formed, the improvement rate of the front luminance of the white light emitting element when the cured film Z was formed was obtained as the improvement rate of the front luminance of the organic EL element.
Front brightness improvement rate 1.5 times or more: Excellent (◎),
Front brightness improvement rate of 1.2 times to less than 1.5 times: good (○),
Front brightness improvement rate less than 1.2 times: Possible (△)

<< Luminous appearance (dark spots, unevenness) >>
A forward current of 10 mA / cm ^{2 was} applied to the light-emitting element of each organic EL element at room temperature, and the light emission appearance (dark spots, unevenness) was observed.
Dark spots and unevenness are not observed: Good (○),
Dark spots and unevenness are slightly observed: Yes (△),
Dark spots and unevenness are observed: Impossible (×)

<< Wavelength dependence >>
Evaluation was made based on the difference in front luminance in the light emitting device using the red, blue, and green light emitting layers shown in Table 2 and the presence or absence of a change in the shape of the emission spectrum in the light emitting device using the white light emitting layer. The emission spectrum was measured using an MCPD-9800 manufactured by Otsuka Electronics Co., Ltd. The difference in front luminance improvement values of red, blue, and green was less than 10%, and the white spectrum shape was changed. No: Good (○),
The difference in the value of the front luminance improvement rate for each of red, blue, and green is 10% or more and less than 20%, and the white spectrum shape is not changed: Yes (△),
The difference between the values of the front luminance improvement ratios of red, blue, and green is 20% or more and the white spectrum shape is changed: Impossible (×)

(Examples 2 to 5)
Instead of the organic particle A dispersion (A-1) used in Example 1, the organic particle A dispersions (A-2), (A-3), (A-6), and (A-7) are used. In the same manner as in Example 1, a curable film X, a cured film Y, Z, an organic EL element electrode, and an organic EL element were sequentially prepared and evaluated in the same manner.

(Comparative Examples 1-2)
Curability was the same as in Example 1 except that the organic particle A dispersions (A-4) and (A-5) were used instead of the organic particle A dispersion (A-1) used in Example 1. A film X, a cured film Y, Z, an organic EL element electrode, and an organic EL element were sequentially formed and evaluated in the same manner.

(Comparative Examples 3-5)
After creating the cured film Y, the cured film Z, the organic EL element electrode, and the organic EL element were sequentially formed in the same manner as in Example 1 except that the heating conditions were changed as shown in Table 3. evaluated.

(Comparative Example 6)
The organic particle A dispersion liquid (A-1) used in Example 1 was not used, but a curable film X and a cured film Y were prepared in the same manner as in Example 1, and a vapor deposition layer was formed on the cured film Y without heating. The formed electrodes for organic EL elements and organic EL elements were sequentially prepared and evaluated in the same manner.

In Examples 1 to 5, improvement in extraction efficiency was recognized by having a predetermined concavo-convex shape, and no defect in light emission appearance due to a short circuit in the element was confirmed. On the other hand, in Comparative Examples 1 and 2, since the predetermined particle diameter and the coefficient of variation are not satisfied, the average height of the target uneven shape and the ratio of the average interval are not satisfied, and the extraction efficiency and the light emission appearance are poor. It was.
In Comparative Examples 3 to 5, even if the same active energy ray-curable composition as in Example 1 was used, the ratio of the average interval of 200 to 450 nm of the cured film Z was less than 30% due to the difference in heating conditions, and the extraction efficiency was The luminescent appearance was poor. In Comparative Example 6, there was no uneven shape, so the light emission appearance was good, but the extraction efficiency was low.

  As described above, according to the present invention, there is provided an organic EL device capable of further improving the light extraction efficiency without causing a short circuit in the device and achieving sufficiently high light emission efficiency. It becomes possible to provide.

Claims (4)

The manufacturing method of the electrode for organic EL elements containing following process (1)-(4).
(1) An average particle size of the dispersion is 100 to 500 nm, and a dispersion of organic particles A having a coefficient of variation of 30% or less, a dispersion of inorganic particles B, and an active energy ray-curable component C are mixed. An active energy ray-curable composition, wherein the average particle size of the organic particles A in the dispersion of the organic particles A is larger than the average particle size of the inorganic particles B in the dispersion of the inorganic particles B A step of preparing a linear curable composition.
(2) The active energy ray-curable film X, which is coated with the active energy ray-curable composition on a support substrate and then dried and has convex portions due to the organic particles A on the surface, the organic particles A step of forming an active energy ray-curable film X having a thickness of 2 to 20 times the average particle diameter of the organic particles A in the dispersion of A.
(3) A step of irradiating the active energy ray-curable film X with active energy rays to form a cured film Y.

(4) Next, the surface of the cured film Y is heated to break the convex portions so as to leave the ridges, and the concave portions are formed, and the proportion of the concaves and convexes with an interval of 200 to 450 nm is 30% or more. A step of obtaining a cured film Z.
(5) A step of depositing a metal on the cured film Z.   The manufacturing method of the element electrode for organic EL of Claim 1 whose average height of the unevenness | corrugation of the cured film Z is 10-100 nm.   The manufacturing method of the element electrode for organic EL of Claim 1 or 2 whose average particle diameter of the dispersion | distribution of the inorganic particle B is 5-50 nm. The manufacturing method of the organic EL element containing following process (1)-(7).
(1) An average particle size of the dispersion is 100 to 500 nm, and a dispersion of organic particles A having a coefficient of variation of 30% or less, a dispersion of inorganic particles B, and an active energy ray-curable component C are mixed. An active energy ray-curable composition, wherein the average particle size of the organic particles A in the dispersion of the organic particles A is larger than the average particle size of the inorganic particles B in the dispersion of the inorganic particles B A step of preparing a linear curable composition.
(2) The active energy ray-curable film X, which is coated with the active energy ray-curable composition on a support substrate and then dried and has convex portions due to the organic particles A on the surface, the organic particles A step of forming an active energy ray-curable film X having a thickness of 2 to 20 times the average particle diameter of the organic particles A in the dispersion of A.
(3) A step of irradiating the active energy ray-curable film X with active energy rays to form a cured film Y.
(4) Next, the surface of the cured film Y is heated to break the convex portions so as to leave the ridges, and the concave portions are formed, and the proportion of the concaves and convexes with an interval of 200 to 450 nm is 30% or more. A step of obtaining a cured film Z.
(5) A step of manufacturing a device electrode for organic EL by depositing a metal on the cured film Z.
(6) A step of forming an organic layer including a light emitting layer on the organic EL electrode.
(7) A step of forming a transparent electrode on the organic layer including the light emitting layer.
(8) The process of sticking on a transparent support substrate on the said transparent electrode using an adhesive agent.