JP2005306713A - Method of producing inorganic semiconductor- or phosphor-primary particle and inorganic semiconductor- or phosphor-primary particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inorganic semiconductor- or phosphor-primary particle having high luminance and a method of producing the inorganic semiconductor- or the phosphor-primary particle in a liquid phase. <P>SOLUTION: A method of producing inorganic semiconductor- or phosphor-primary particles comprises forming the particles by reacting at least one kind of precursor solution of the inorganic primary particle in a solvent, of which major component is water of a reacting vessel, under the conditions that the pressure is 0.2 to 20 MPa and the temperature is 120°C to 370°C. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing primary particles of an inorganic semiconductor or phosphor, and in particular, high-luminance and long-life electroluminescence containing zinc sulfide as a base material and containing an activator and a coactivator as the center of light emission ( EL) relates to a method for producing inorganic particles for phosphors.

  An inorganic electroluminescence (EL) phosphor is a light-emitting element that emits a phosphor by applying an alternating electric field to inorganic phosphor particles sandwiched between two electrodes. Luminescent materials are known. The dispersion-type EL phosphor has a structure in which phosphor particles of several μm are dispersed in a binder having a high dielectric constant, and at least one is sandwiched between two transparent electrodes. It is a surface light emitter that can be made thick, and has many advantages such as no heat generation and good luminous efficiency. Therefore, it is expected to be used for road signs, illumination for various interiors and exteriors, light sources for flat panel displays such as liquid crystal displays, and illumination light sources for large areas.

  As the phosphor particles used for the inorganic EL phosphor, those obtained by adding an activator (metal ion as a light emission center) to inorganic semiconductor particles are used. Generally, zinc sulfide is used as a base, and copper or the like is used. Those to which an activator and a coactivator such as chlorine are added are widely known. However, light-emitting elements made using these phosphor particles have the disadvantages of lower emission brightness and shorter emission lifetime than light-emitting elements based on other principles. Has been tried.

  In order to synthesize phosphor particles based on zinc sulfide, the raw material zinc sulfide nanoparticles are first baked at a very high temperature of 1300 ° C. to 1000 ° C. together with an inorganic salt called a flux into micron-sized particles. The mainstream method is to obtain the phosphor particles by growing and subsequently performing second baking at 500 to 1000 ° C. This manufacturing method is described in Patent Documents 1 to 3, for example. However, in this method, since firing is performed in a high-temperature furnace, it is difficult to add a substance to the system from the start to the end of the firing. For example, the concentration distribution of the activator or the coactivator inside the particle is determined within the particle. It is impossible to change. For this reason, it has been difficult to obtain further bright zinc sulfide phosphor particles.

  On the other hand, when synthesizing zinc sulfide particles in the liquid phase, it is possible to add an activator or a coactivator while controlling the amount of the particles during the growth of the particles. It is possible to generate phosphor particles in which the concentration distribution of the activator or coactivator inside is changed. It is also possible to obtain monodisperse zinc sulfide particles having a narrow size distribution by forming particles by separating nucleation and growth and controlling the degree of supersaturation during particle growth.

Regarding the method of synthesizing zinc sulfide particles for inorganic EL phosphors in the liquid phase, Patent Document 4 discloses a method of synthesizing nano-sized particles in water, and Non-Patent Documents 1 to 3 describe crystals of zinc sulfide in water. Has been reported to grow to sub-micron size. However, the spherical particles obtained in Non-Patent Document 1 are secondary particles (aggregated particles) formed by agglomerating nano-sized microcrystals, and the particles of Non-Patent Document 2 are also small-sized particles. Aggregates, which are desirable micron-sized primary particles as EL phosphor particles, have not been obtained. On the other hand, in Non-Patent Document 3, submicron-sized zinc sulfide primary particles are obtained by putting pre-formed nano-sized particles in a sealed container and aging at high temperature, but this method makes modification difficult during particle growth. Therefore, it is impossible to control the concentration distribution of the activator and coactivator inside the particles, and control the particle size distribution.
Japanese Patent Laid-Open No. 8-183954 JP-A-7-62342 JP-A-6-330035 JP 2002-31568 A “Fine Particles” (Fine PARTICLES, fluid science series, volume 92, edited by Sugimoto), p190-196 "Colloids and Surface A", vol.135, p.207-226 (1998) "Crystal Research Technology", vol.35, p.279-289 (2000)

  The present invention solves the above-mentioned problems in conventional inorganic EL phosphor particles, and aims to provide a method for producing micron-sized inorganic semiconductor or phosphor primary particles in a liquid phase, It is an object of the present invention to provide a method for producing a phosphor based on zinc sulfide.

The object of the present invention can be solved by the following means.
(1) It is characterized in that particles are formed by reacting at least one precursor solution in a solvent mainly composed of water in a reaction vessel set at a pressure of 0.2 to 20 MPa and a temperature of 120 to 370 ° C. A method for producing inorganic semiconductor primary particles.
(2) It is characterized in that particles are formed by reacting at least one precursor solution in a solvent mainly composed of water in a reaction vessel set at a pressure of 0.2 to 20 MPa and a temperature of 120 to 370 ° C. A method for producing primary particles of inorganic phosphor.
(3) The method for producing inorganic particles according to (1) to (2), wherein the precursor solution is an ionic aqueous solution.
(4) The method for producing inorganic particles according to (1) to (2), wherein the precursor solution is a solution containing inorganic fine particles having an average particle diameter of 1 to 50 nm.
(5) An aqueous solution containing sulfur ions and an aqueous solution containing zinc ions are added and reacted, and the sulfur ion concentration in the reaction solution is adjusted to be 10 ⁻⁵ to 10 mol / L excess with respect to the zinc ion concentration. The method for producing inorganic particles according to (3), characterized in that zinc sulfide having an average particle diameter of 0.5 to 50 μm formed as particles is used as a base.
(6) The method for producing inorganic particles according to any one of (1) to (5), wherein a chelating agent having an amino group or a carboxyl group is added.
(7) As an activator, at least one metal element selected from the group consisting of copper, manganese, silver, gold and rare earth elements is added. Any one of (1) to (6) The manufacturing method of the inorganic particle as described in any one of.
(8) The method for producing inorganic particles according to (7), wherein the metal element as the activator is added by mixing the metal ion solution and the chelating agent.
(9) Any one of (1) to (8), wherein an ion solution of at least one element selected from the group consisting of chlorine, bromine, iodine, and aluminum is added as a coactivator. The manufacturing method of the inorganic particle as described in claim | item.
(10) Inorganic particles produced by the method according to any one of (1) to (9), wherein the solubility product pKsp in water at 25 ° C. of the particles is in the range of 17-40. An inorganic semiconductor or phosphor primary particle characterized by.
(11) Inorganic particles produced by the method according to any one of (1) to (9), wherein the average particle size of the particles is in the range of 0.1 to 100 μm. Inorganic semiconductor or phosphor primary particles.
(12) An inorganic semiconductor or phosphor primary particle produced by the method according to any one of (1) to (9), wherein the particle is a metal sulfide.
(13) An inorganic particle or phosphor primary particle produced by the method according to any one of (1) to (9), wherein the particle is a metal oxide.
(14) An inorganic semiconductor or phosphor primary particle, wherein the inorganic particle is produced by the method according to any one of (1) to (9), and the particle is a metal nitride.
(15) Inorganic semiconductor or phosphor primary particles produced by the method according to any one of (1) to (9), wherein the particles are based on zinc sulfide. .

  According to the present invention, phosphor particles that are semiconductor or phosphor primary particles that are not aggregates of nano-sized particles and that have high luminance particularly for EL can be efficiently produced in a liquid phase.

Hereinafter, the present invention will be described in detail.
The inorganic semiconductor in the present invention is typically one or more elements selected from the group consisting of Group II elements and Group VI elements, and a group consisting of Group III elements and Group V elements. A semiconductor composed of one or more selected elements can be given. Examples thereof include CdS, CdSe, CdTe, ZnS, ZnSe, ZnSSe, ZnTe, CaS, MgS, SrS, GaP, GaAs, ZnO, GaN, InN, AlN, and mixed crystals thereof. Among these, ZnS, ZnSe, ZnSSe, CaS, CaSrS, ZnO and the like can be preferably used, and ZnS or ZnSSe is particularly preferable.

The inorganic phosphor in the present invention is typically a group consisting of one or more elements selected from the group consisting of Group II elements and Group VI elements, and Group III elements and Group V elements. And phosphors composed of one or more elements selected from For example, as the base material of the phosphor, CdS, CdSe, CdTe, ZnS, ZnSe, ZnSSe, ZnTe, CaS, MgS, SrS, GaP, GaAs, BaAl ₂ S ₄ , Ba ₂ SiO ₄ , BaMgAl ₁₀ O ₁₇ , CaGa ₂ S ₄ , Ga ₂ O ₃ , ZnO, Zn ₂ SiO ₄ , Zn ₂ GaO ₄ , ZnGa ₂ O ₄ , ZnGeO ₃ , ZnGeO ₄ , ZnAl ₂ O ₄ , CaGa ₂ O ₄ , CaGa ₂ S ₄ , CaGeO ₃ , Ca ₂ Ge ₂ O ₇ , CaO, CaWO ₄ , Ga ₂ O ₃ , GeO ₂ , SrAl ₂ O ₄ , SrGa ₂ O ₄ , SrGa ₂ S ₄ , SrP ₂ O ₇ , MgGa ₂ O ₄ , Mg ₂ GeO ₄ , MgGeO ₃ , BaAl ₂ O ₄ , Ga ₂ Ge ₂ O ₇ , BeGa ₂ O ₄ , Y ₂ SiO ₅ , Y ₂ GeO ₅ , Y ₂ Ge ₂ O ₇ , Y ₄ GeO ₈ , Y ₂ O ₃ , Y ₂ O _{2 S, YVO 4, YAlO 3,} YBO 3, SnO 2, Gd 2 O 2 S, La 2 O 2 S, LaOBr, La 2 O 2 S, GaN, InN, AlN or the like, and mixed crystals thereof are exemplified. Among these, ZnS, ZnSe, ZnSSe, CaS, CaSrS, ZnO and the like can be preferably used, and ZnS or ZnSSe is particularly preferable. In addition, the activator and coactivator that are contained in the phosphor matrix to form the luminescent center are Cu, Mn, Ag, Al, Au, Ga, Tl, Sn, Pb, Sb, Bi, Ti and other metal ions and Rare earth element ions such as Eu, Ce, Tb and Sm, and halide ions such as Cl and Br are preferably used.

  Many of these semiconductor or phosphor particles are poorly water-soluble, but can be produced even in the liquid phase according to the production method of the present invention. The generated semiconductor or phosphor particles are preferably 17 to 40, more preferably 17 to 35, and most preferably 17 to 28 in terms of solubility product pKsp (25 ° C.) in water. The solubility product pKsp (25 ° C.) of each semiconductor or phosphor particle can be easily determined from the solubility described in “Chemical Handbook” edited by the Chemical Society of Japan, for example.

  These poorly water-soluble semiconductor or phosphor compounds have a problem of low solubility in forming as micron-sized primary particles. Therefore, in the present invention, a liquid phase under high temperature and high pressure conditions is used for particle formation. The particle formation is performed with a solvent mainly containing water, preferably 50 vol% or more, more preferably 70 vol% or more, and the temperature condition is preferably 120 to 370 ° C, more preferably 150 to 350 ° C, still more preferably. 200-350 ° C. However, if the temperature of the solvent is raised too much, it becomes a supercritical state and, on the contrary, the solubility is lowered. In the case of water, it becomes a supercritical state at 375 ° C. or higher. In order to obtain a high temperature of 100 ° C. or higher with an aqueous solvent, a reaction container having a high pressure-resistant structure with high hermeticity is required. At this time, the saturated vapor pressure of the pressure in the container increases with temperature. In the present invention, the pressure in the container may be the saturated vapor pressure, or pressure may be applied from the outside. The pressure condition of the present invention is preferably 0.2 to 20 MPa, more preferably 0.5 to 15 MPa, and still more preferably 1.5 to 15 MPa. In the present invention, the aqueous solvent is a solvent mainly composed of water, and preferably refers to a solvent containing at least 50% by mass of water.

  The inorganic semiconductor or phosphor primary particles of the present invention are produced by adding at least one reaction solution (precursor solution) to the liquid phase under such a high temperature and high pressure condition. Here, the reaction solution is, for example, an ionic aqueous solution containing an element constituting an inorganic semiconductor or phosphor primary particles, a solution of a compound that is hydrolyzed by heating to produce an inorganic semiconductor or phosphor primary particles, an inorganic semiconductor or Examples thereof include a solution containing phosphor fine particles.

  The semiconductor or phosphor fine particle solution used as the reaction solution is added as a mixed solution with a solvent containing 50 vol% or more of water. The semiconductor or phosphor fine particle solution may be a solution prepared in advance, or may be prepared and added immediately before the addition in another reactor during particle formation. As another reaction apparatus, JP-B-7-23218, JP-A-10-43570 and the like can be referred to. The concentration of the semiconductor or phosphor fine particle solution used is preferably 1 mM or more and 5 M or less, more preferably 5 mM or more and 3 M or less. As the semiconductor or phosphor fine particle solution, at least one kind of solution can be added. For example, a solution having a different average particle diameter or a solution having a different concentration may be added in combination. The semiconductor or phosphor fine particle solution may be added alone or in combination with other ionic solutions. For example, it is possible to change the particle growth by adding it together with a solution of the compound that dissolves the fine particles.

  The reaction solution for producing the inorganic semiconductor or phosphor particles is continuously added. In that case, the aqueous solution of an activator and a coactivator can also be continuously added simultaneously. Various addition patterns are possible. For example, it is preferable to determine the addition rate of the solution in order to achieve the optimum degree of supersaturation separately for the nucleation and growth steps. The solution may be added at a constant flow rate or intermittently. Alternatively, the addition flow rate may be increased stepwise or continuously, or the addition flow rate may be decreased stepwise or continuously. The same applies to the addition of an aqueous solution of an activator and a coactivator. The time required for particle generation is preferably within 100 hours, more preferably within 12 hours and 5 minutes or more. An Ostwald ripening step is preferably provided between the nucleation process and the growth process in order to adjust the particle size. This Ostwald ripening is preferably performed at a temperature of 120 ° C. to 370 ° C., more preferably 200 ° C. to 350 ° C., and the aging time is preferably 5 minutes to 50 hours, more preferably 20 minutes to 10 hours. is there.

  Regarding the concentration of the reaction solution in the reaction vessel, the concentration of the produced inorganic semiconductor or phosphor particles is preferably 1 mM or more and 5 M or less, more preferably 5 mM or more and 3 M or less.

  The average particle size of the semiconductor or phosphor particles produced in the present invention is preferably 0.1 to 100 μm, more preferably 0.5 to 50 μm, and most preferably 1 to 30 μm. The average particle diameter is represented by an average value of 200 equivalent circle diameters measured from SEM (scanning electron microscope) photographs of the particles. The generated semiconductor or phosphor particles are obtained as primary particles. Here, the secondary particles are particles in which smaller particles are aggregated to increase the apparent particle size, and the primary particles are particles that are not aggregated. On the other hand, the average particle diameter of the semiconductor or phosphor fine particles used in the reaction solution is 200 average circle diameters measured from a TEM (transmission electron microscope) photograph of the particles, and is expressed as an average value thereof, preferably 1 to 50 nm. More preferably, it is 1-30 nm. The semiconductor or phosphor fine particles may be either primary particles or secondary particles.

  The apparatus used for the production of the inorganic semiconductor or phosphor primary particles of the present invention is a reaction vessel set at a high pressure and a high pressure of 0.2 to 20 MPa and a temperature of 120 to 370 ° C., for example, a semiconductor or phosphor fine particle solution. Therefore, it is preferable that a pipe capable of injecting an aqueous solution into the pressure vessel and a pressure-resistant precision pump can be used. As the material of the device, for example, a pressure-resistant and heat-resistant glass, a metal material such as Teflon material (trade name, tetrafluoroethylene), stainless steel, or the like is used according to the temperature and pressure to be used. However, in the case of a metal material, the metal which becomes an impurity elutes from a pressure vessel during particle formation, and the desired performance may not be expressed. For example, in EL phosphors based on zinc sulfide, iron, nickel, and cobalt are harmful metal ions that suppress light emission and must be avoided. Therefore, materials that do not contain harmful ions are used for pressure-resistant containers, addition pipes, stirrers, and other parts that come into contact with liquid used for particle formation. The material of the apparatus for producing the inorganic semiconductor or phosphor primary particles of the present invention is preferably a Teflon material, Hastelloy (trade name), or a titanium material. Moreover, it is preferable that the manufacturing apparatus used in the present invention includes a stirring mechanism. With regard to the stirring device, reference can be made to JP-B 55-10545, JP-B 49-48964 and the like.

Next, the present invention will be described in detail by taking phosphor particles for electroluminescence (hereinafter referred to as “EL phosphor particles”) based on zinc sulfide as an example.
In the present invention, in order to obtain zinc sulfide particles, it is preferable to keep the sulfur ion concentration during the reaction excessive. The excess sulfur ion concentration is preferably 10 ⁻⁵ to 10 mol / L with respect to the stoichiometric amount, that is, zinc ion, and preferably 10 ⁻³ to 1 mol / L. Excess sulfur ions may be added in advance to the aqueous solvent before the reaction, or an extra sulfur ion solution may be added to the zinc ion solution during the reaction.

  In the present invention, a chelating agent can be preferably used as a method for increasing the solubility of zinc sulfide in water when forming the zinc sulfide particles. As the chelating agent for zinc ions, those having an amino group or a carboxyl group are preferable. Specifically, ethylenediaminetetraacetic acid (hereinafter referred to as EDTA), N, 2-hydroxyethylethylenediaminetriacetic acid (hereinafter referred to as EDTA-OH). ), Diethylenetriaminepentaacetic acid, 2-aminoethylethyleneglycoltetraacetic acid, 1,3-diamino-2-hydroxypropanetetraacetic acid, nitrilotriacetic acid, 2-hydroxyethyliminodiacetic acid, iminodiacetic acid, 2-hydroxyethylglycine, Examples include ammonia, methylamine, ethylamine, propylamine, diethylamine, diethylenetriamine, triaminotriethylamine, allylamine, and ethanolamine. The chelating agent may be used after being dissolved in an aqueous solvent before the reaction, can be added alone as an aqueous solution, or can be added by mixing with a fine particle solution or the like.

  The activator that becomes the emission center of the EL phosphor of the zinc sulfide matrix may be any one that is generally used for phosphors as an activator, for example, various kinds of elements such as copper, manganese, silver, gold, and rare earth elements. These metal ions are preferably used. Specifically, acetates and sulfates of these elements are preferably used. These may be used alone or in combination. The wavelength (color) of the fluorescence emission depends on the type of the activator. For example, fluorescence such as blue-green (copper), orange (manganese), and blue (silver) is obtained. The preferred concentration of the activator depends on the type of the activator. For example, in the case of a copper activator, if the copper concentration is in the range of 0.01 to 0.5 mol% with respect to zinc sulfide of the base material of the final product, Good. In order to dope the activator into the zinc sulfide particles, it is preferable to form a complex of the doped substance and add it during or before the particle formation. As the complex-forming compound, the aforementioned chelating agent can be preferably used. At that time, the solubility of the complex of the doping substance is preferably close to the solubility of the zinc sulfide particles. Regarding this, reference can be made to JP-A-2002-338961.

  As the coactivator, a compound of halide ion or aluminum ion is preferable, and for example, a compound containing at least one element selected from the group consisting of chlorine, bromine, iodine, and aluminum is more preferable. Most preferably, nitrates or sulfates of aluminum ions are used. The preferred concentration of the coactivator depends on the type of coactivator. For example, in the case of an aluminum coactivator, the aluminum concentration is in the range of 0.01 to 0.5 mol% with respect to zinc sulfide of the base material of the final product. I just need it. When aluminum ions are used as the coactivator, it is preferable to add them before or after adding the aqueous solution of activator ions by mixing with the chelating agent.

  Regarding the doping of the activator and coactivator into the EL phosphor particles, once the zinc sulfide particles are prepared in the liquid phase, they are dried to a powder, and the activator and / or the co-activator is added to the powder. It can also dope by adding an activator and baking. At that time, the firing temperature is preferably 300 to 1200 ° C, more preferably 400 to 1000 ° C, and the firing time is preferably 30 minutes to 10 hours, more preferably 1 to 7 hours. During this firing, a flux can also be added. Examples of the flux include sodium chloride, magnesium chloride, barium chloride, and ammonium chloride.

  Further, impact modification (treatment for applying an impact force in a size that does not destroy the particles) performed for improving the light emission characteristics of the EL phosphor by the firing method can also be used for the EL phosphor particles of the present invention. As a method of applying an impact force, a method of bringing particles into contact with each other, a method of mixing and mixing spheres such as alumina (ball mill), a method of accelerating and colliding particles, a method of irradiating ultrasonic waves, and the like are preferably used.

  The EL phosphor particles of the present invention can also have a non-light emitting shell layer on the surface of the particles. The shell layer is preferably formed with a thickness of 0.01 μm or more using a chemical method following the preparation of the phosphor to be the core. Preferably it is the range of 0.01 micrometer or more and 1.0 micrometer or less. The non-light-emitting shell layer can be formed from an oxide, nitride, oxynitride, or a material that is formed on the base phosphor particles and has the same composition and does not contain an emission center. It can also be formed by epitaxially growing substances having different compositions on the host phosphor particle material. As a method of forming the non-light emitting shell layer, a laser ablation method, a CVD method, a plasma CVD method, a sputtering method, a resistance heating method, an electron beam method, and a gas phase method such as a method combining fluid oil surface deposition, a metathesis method, Sol-gel method, ultrasonic chemistry method, precursor thermal decomposition method, reverse micelle method or a combination of these methods with high-temperature firing, hydrothermal synthesis method, urea melting method, freeze drying method, etc. A thermal decomposition method or the like can also be used. In the present invention, since the phosphor particles are synthesized in the liquid phase, it is particularly suitable for forming a non-light emitting shell layer by a liquid phase method.

  The zinc phosphor matrix EL phosphor doped with the activator and coactivator thus obtained is washed with water, dried, washed with hydrochloric acid and potassium cyanide solution, and dried to obtain an EL phosphor powder. . This phosphor is dispersed in an organic binder and coated to form an EL light emitting layer. An electroluminescent lamp (EL light-emitting element) is completed by sealing and sealing the electroluminescent element in which the light-emitting layer is disposed between the reflective insulating layer on the back electrode and the transparent electrode with an outer film. When a voltage is applied between both electrodes, the phosphor in the light emitting layer emits light due to a high electric field formed on both electrodes. When the phosphor particles are subjected to a high electric field, the electric field concentrates on the conductive layer in which the activator, for example, copper ions, in the particle is localized, where a very high electric field is generated, and electrons and holes are generated from this conductive layer. The light is emitted when they recombine via an activator or coactivator. In EL phosphor particles, it is very important to efficiently generate and recombine electrons. It is considered that the zinc sulfide phosphor particles of the present invention can localize activator ions and coactivator ions freely in the particles, and enable effective electron generation and recombination. Furthermore, since the phosphor particles of the present invention have a uniform particle size distribution and little variation in the particle structure, it is possible to bring about higher luminous efficiency.

Subsequently, an EL light emitting device (hereinafter referred to as EL device) using the zinc sulfide EL phosphor particles of the present invention will be described in detail.
The EL element of the present invention has a structure in which a light emitting layer is sandwiched between a pair of opposing electrodes, at least one of which is transparent. It is preferable that a dielectric layer is adjacent between the light emitting layer and the electrode. As the light emitting layer, a material in which phosphor particles are dispersed in a binder can be used. As the binder, a polymer having a relatively high dielectric constant such as a cyanoethyl cellulose resin, or a resin such as polyethylene, polypropylene, polystyrene resin, silicone resin, epoxy resin, or vinylidene fluoride can be used. The dielectric constant can be adjusted by appropriately mixing fine particles having a high dielectric constant such as BaTiO ₃ and SrTiO _{3 with} these resins. As a dispersion method, a homogenizer, a planetary kneader, a roll kneader, an ultrasonic disperser, or the like can be used. As the dielectric layer, any material can be used as long as it has a high dielectric constant and insulation and has a high dielectric breakdown voltage. These metal oxides are selected from nitrides, for example _{TiO 2, BaTiO 3, SrTiO 3} , PbTiO 3, KNbO 3, PbNbO 3, Ta 2 O 3, BaTa 2 O 6, LiTaO 3, Y 2 O 3, Al ₂ O ₃ , ZrO ₂ , AlON, ZnS or the like is used. These may be installed as a uniform film, or may be used as a film having a particle structure. In the case of a uniform film, the dielectric film may be prepared by a vapor phase method such as sputtering or vacuum deposition. In this case, the thickness of the film is usually in the range of 0.1 μm to 10 μm. In the element configuration of the present invention, various protective layers, filter layers, light scattering reflection layers, and the like can be provided as necessary.

  The EL phosphor particle-containing coating liquid or the dielectric fine particle-containing coating liquid used for the manufacture of the EL element is a coating liquid containing at least an EL phosphor particle or dielectric fine particle, a binder, and a solvent for dissolving the binder. is there. The viscosity of the EL phosphor particle-containing coating solution or dielectric fine particle-containing coating solution at room temperature is preferably in the range of 0.1 Pa · s to 5 Pa · s, and in the range of 0.3 Pa · s to 1.0 Pa · s. Is particularly preferred. When the viscosity of the coating solution containing EL phosphor particles or the coating solution containing dielectric fine particles is too low, the coating film thickness unevenness is likely to occur, and the phosphor particles or dielectric fine particles are separated over time after dispersion. May settle. On the other hand, when the viscosity of the EL phosphor particle-containing coating solution or the dielectric fine particle-containing coating solution is too high, coating at a relatively high speed becomes difficult. The viscosity is a value measured at 16 ° C. which is the same as the coating temperature.

  Using a slide coater or an extrusion coater, the light emitting layer is continuously formed on a plastic support or the like provided with a transparent electrode so that the dry film thickness of the coating film is in the range of 0.5 μm to 30 μm. It is preferable to apply. At this time, the film thickness variation of the light emitting layer is preferably 12.5% or less, particularly preferably 5% or less.

  Each functional layer coated on the support is preferably a continuous process from at least the coating to the drying process. The drying process is divided into a constant rate drying process until the coating film is dried and solidified, and a decreasing rate drying process for reducing the residual solvent of the coating film. In the present invention, since the binder ratio of each functional layer is high, when rapidly dried, only the surface is dried and convection occurs in the coating film, so-called Benard cell is likely to occur, and blister failure is caused by rapid solvent expansion. It tends to occur and the uniformity of the coating film is significantly impaired. On the other hand, if the final drying temperature is low, the solvent remains in each functional layer, which affects the subsequent process of forming EL elements such as a moisture-proof film laminating process. Therefore, it is preferable that the drying step is performed slowly at a constant rate drying step and performed at a temperature sufficient for the solvent to dry. As a method for slowly performing the constant rate drying step, it is preferable to divide the drying chamber in which the support travels into several zones and increase the drying temperature after the coating step in a stepwise manner.

  In the production of the EL device of the present invention, preferably, the light emitting layer is calendered using a calendering machine. The smoothness of both main surfaces of the light-emitting layer formed by the calendar process is preferably in the range of 0.5 μm or less, more preferably 0.2 μm or less in terms of 10-point average roughness. The calendar processing machine to be used is not particularly limited, and can be appropriately selected from known apparatuses. A smoothing process is performed by passing a light-emitting layer in which phosphor particles are dispersed in a binder while applying pressure between a pair of rolls heated at 50 ° C. to 200 ° C., for example, at least one of them. . In the calendering process, it is preferable that the heating temperature of the calender roll is equal to or higher than the softening temperature of the binder contained in the light emitting layer. In addition, the calender pressure and transport speed can be obtained by taking into account the calender temperature and the width of the EL light emitting layer so as not to destroy the phosphor particles or extend the light emitting layer more than necessary. It is preferable to select as appropriate.

  In the EL device of the present invention, any transparent electrode material that is generally used is used as the transparent electrode. Examples thereof include oxides such as tin-doped tin oxide, antimony-doped tin oxide, and zinc-doped tin oxide, a multilayer structure in which a silver thin film is sandwiched between high refractive index layers, and π-conjugated polymers such as polyaniline and polypyrrole. It is also preferred to improve the conductivity by arranging a comb-type or grid-type fine metal wire on these transparent electrodes. The specific resistivity of the transparent electrode is preferably in the range of 0.01Ω / □ to 30Ω / □. For the back electrode on the side from which light is not extracted, any conductive material can be used. It is selected from gold, silver, platinum, copper, iron, aluminum and other metals, graphite, etc. depending on the form of the element to be created, the temperature of the production process, etc. It may be used. Further, both electrodes can be prepared by preparing a conductive material-containing coating solution in which the conductive fine particle material is dispersed together with a binder, and using the above-described slide coater or extrusion coater.

  The conductive material described above can also be used when a compensation electrode is provided to suppress vibration of the EL element. For example, when a compensation electrode is provided outside the transparent electrode from which light is extracted, an oxide such as tin-doped tin oxide, antimony-doped tin oxide, or zinc-doped tin oxide, and a multilayer structure in which a thin film of silver is sandwiched between high refractive index layers It is preferable to use transparent electrode materials such as π-conjugated polymers such as polyaniline and polypyrrole.

  In addition, when a compensation electrode is provided outside the back electrode from which light is not extracted, any conductive material such as metal such as gold, silver, platinum, copper, iron, aluminum, graphite, etc. can be used. A transparent electrode such as ITO may be used as long as it has the property. The compensation electrode is attached to the transparent electrode or the back electrode via an insulating layer. The insulating layer material is an insulating inorganic material or polymer material, a dispersion liquid in which inorganic material powder is dispersed in a polymer material, or the like. Can be formed by vapor deposition, coating, or the like. Alternatively, a conductive material-containing coating solution in which the conductive fine particle material is dispersed together with a binder can be prepared and applied using the above-described slide coater or extrusion coater. Furthermore, an insulating material-containing coating solution in which the insulating material is dispersed together with a binder can be prepared and applied simultaneously with the conductive material-containing coating solution. A voltage is applied to the compensation electrode provided from the drive power supply. At this time, the vibration generated in the light emitting layer can be canceled by setting the phase opposite to the voltage applied to the light emitting layer. The compensation electrode has the same effect even if it is attached to either the outside of the transparent electrode or the outside of the back electrode with an insulating layer sandwiched between them. It is preferable because it is possible. In order to effectively suppress vibrations, it is preferable to adjust the dielectric constant of the light emitting layer (and the dielectric layer) and the dielectric constant of the insulating layer inside the compensation electrode to be substantially equal.

  As another method for suppressing vibration of the EL element, when a buffer material layer used for the EL element is provided, a polymer material having a high impact absorbing ability or a polymer material foamed by adding a foaming agent may be used. preferable. Examples of polymer materials with high impact absorption include natural rubber, styrene butadiene rubber, polyisoprene rubber, polybutadiene rubber, nitrile rubber, chloroprene rubber, butyl rubber, Hypalon (trade name), silicon rubber, urethane rubber, ethylene propylene rubber, Fluororubber can be used. The hardness of these polymer materials is preferably 50 or less, more preferably 30 or less, from the viewpoint of vibration absorption ability. In addition, butyl rubber, silicon rubber, fluorine rubber, and the like are more preferable because they have low water absorption and function as a protective film that protects the EL element from moisture. It is also preferable to use as a buffer material a material obtained by adding a foaming agent to the above rubber material, polypropylene, polystyrene, or polyethylene resin. The buffer material layer using these buffer materials can be attached by adhering the buffer material layer to the EL element with an adhesive, but the buffer material is dissolved in a solvent to prepare a buffer material-containing coating solution, It can also apply | coat using the above-mentioned slide coater or extrusion coater. Although the thickness of the buffer material layer depends on the hardness of the polymer material, it needs to be 20 μm or more and preferably 50 μm or more in order to sufficiently absorb vibration. When the thickness is 200 μm or more, the thickness of the element increases greatly, which is not preferable in terms of mass and flexibility. Further, the combined use of the compensation electrode and the buffer material layer is preferable because vibration can be further suppressed.

  In the EL element, it is preferable to use a thinned light emitting layer. When the light emitting layer is thinned, the voltage applied to the light emitting layer is higher than that when the light emitting layer is thick as in the conventional EL element under the same driving conditions, so that the luminance is increased. In the case of driving with a luminance comparable to that of a conventional EL element, the driving voltage and frequency can be lowered, so that power consumption is reduced and vibration and noise can be further improved. In order to obtain such an effect, the light emitting layer preferably has a thickness of 0.5 μm or more and 30 μm or less, and particularly preferably 15 μm or less. Furthermore, the total film thickness of the light emitting layer containing the phosphor particles and the dielectric layer containing the inorganic dielectric particles adjacent to the light emitting layer containing the phosphor particles as necessary is preferably in the range of 1 μm or more and 50 μm or less, In particular, it is preferably 30 μm or less.

  The phosphor particles of the present invention preferably have an average particle size in the range of 0.1 μm to 15 μm in order to uniformly form a light emitting layer of 30 μm or less. Moreover, although it does not restrict | limit to the filling rate of the fluorescent substance particle in a light emitting layer, Preferably it is the range of 60 mass% or more and 95 mass% or less, More preferably, it is the range of 80 mass% or more and 90 mass% or less. In one embodiment of the present invention, by setting the particle size of the phosphor particles to 15 μm or less, the uniformity of the coating film thickness of the light emitting layer is improved, and the smoothness of the coating film surface is simultaneously improved. Furthermore, when the number of particles per unit area is greatly increased, fine light emission unevenness can be remarkably improved. Furthermore, the decrease in the particle size leads to an increase in the applied voltage of the phosphor particles, which is preferable for improving the luminance of the EL element in combination with the increase in the electric field strength to the light emitting layer due to the thinning of the light emitting layer. It is also preferable for suppression of vibration.

  The dielectric particles may be a thin film crystal layer or a particle shape. A combination thereof may also be used. The dielectric layer containing the dielectric particles may be provided on one side of the phosphor particle layer, and is preferably provided on both sides of the phosphor particle layer. When the dielectric layer is formed by coating, it is preferable to use a slide coater or an extrusion coater similarly to the light emitting layer. In the case of a thin film crystal layer, it may be a thin film formed on a substrate by a vapor phase method such as sputtering, or a sol-gel film using an alkoxide such as Ba or Sr. In the case of a particle shape, it is preferable that the size is sufficiently small with respect to the size of the phosphor particles. Specifically, a size in the range of 1/1000 to 1/3 of the phosphor particle size is preferable.

The dispersion-type EL element is finally processed using a sealing film so as to eliminate the influence of humidity and oxygen from the external environment. Sealing film for sealing the EL element is preferably not more than the water vapor transmission rate of 0.05g / m ² / day at 40 ° C. 90% RH, more preferably at most 0.01g / m ² / day. Furthermore, the oxygen permeability at 40 ° C. and 90% RH is preferably 0.1 cm ³ / m ² / day / atm or less, and more preferably 0.01 cm ³ / m ² / day / atm or less. As such a sealing film, a laminated film of an organic film and an inorganic film is preferably used. As the organic film, a polyethylene resin, a polypropylene resin, a polycarbonate resin, a polyvinyl alcohol resin, or the like is preferably used, and in particular, a polyvinyl alcohol resin can be more preferably used. Since polyvinyl alcohol resins and the like have water absorption properties, it is more preferable to use a resin that has been dried in advance by a treatment such as vacuum heating.

An inorganic film is deposited by vapor deposition, sputtering, CVD, or the like on these resins processed into a sheet by a method such as coating. As the inorganic film to be deposited, silicon oxide, silicon nitride, silicon oxynitride, silicon oxide / aluminum oxide, aluminum nitride, or the like is preferably used, and silicon oxide is particularly preferably used. In order to obtain a lower water vapor transmission rate and oxygen transmission rate, and to prevent the inorganic film from cracking due to bending, etc., the formation of the organic film and the inorganic film is repeated, or the organic film deposited with the inorganic film is used as an adhesive layer. It is preferable that a plurality of films are bonded together to form a multilayer film. The thickness of the organic film is preferably in the range of 5 μm to 300 μm, and more preferably in the range of 10 μm to 200 μm. The thickness of the inorganic film is preferably in the range of 10 nm to 300 nm, and more preferably in the range of 20 nm to 200 nm. The thickness of the laminated sealing film is preferably in the range of 30 μm to 1000 μm, and more preferably in the range of 50 μm to 300 μm. For example, in order to obtain a sealing film having a water vapor transmission rate of 0.05 g / m ² / day or less at 40 ° C. and 90% RH, in the configuration in which two layers of the organic film and the inorganic film are laminated, 50 to A film thickness of 100 μm is sufficient, but polychlorinated ethylene trifluoride conventionally used as a sealing film requires a film thickness of 200 μm or more. The thinner the sealing film, the better in terms of light transmission and device flexibility.

  When sealing an EL cell with this sealing film, even if the EL cell is sandwiched between two sealing films and the periphery is adhesively sealed, the sealing film overlaps by folding one sealing film in half The part may be adhesively sealed. As the EL cell sealed with the sealing film, only the EL cell may be separately prepared, or the EL cell may be directly formed on the sealing film. The sealing step is preferably performed in a dry atmosphere with vacuum or dew point management.

  Even when an advanced sealing process is performed, it is preferable to dispose a desiccant layer around the EL cell. As the desiccant (hygroscopic agent) used in the desiccant layer, alkaline earth metal oxides such as CaO, SrO and BaO, aluminum oxide, zeolite, activated carbon, silica gel, paper and highly hygroscopic resin are preferably used. However, alkaline earth metal oxides are more preferable in terms of moisture absorption performance. These desiccants can be used even in powder form. For example, the desiccant can be mixed with a resin material and processed into a sheet by coating or molding, or a coating liquid mixed with a resin material can be used as a dispenser. It is preferable to dispose the desiccant layer by applying it around the EL element. Furthermore, it is more preferable to cover not only the periphery of the EL cell but also the lower and upper surfaces of the EL cell with a desiccant. In this case, it is preferable to select a highly transparent desiccant layer for the light extraction surface. As the highly transparent desiccant layer, a polyamide-based resin or the like can be used.

  The use of the present invention is not particularly limited, but considering the use as a light source, the emission color is preferably white. Examples of a method for making the emission color white include a method using phosphor particles that emit white light alone, such as a zinc sulfide phosphor activated with copper and manganese and gradually cooled after firing, or three primary colors or complementary colors A method of mixing a plurality of phosphors emitting light in relation is preferable (a blue-green-red combination, a blue-green-orange combination, etc.). In addition, light is emitted at a short wavelength such as blue described in JP-A-7-166161, JP-A-9-245511, and JP-A-2002-62530, and light emission is performed using a fluorescent pigment or a fluorescent dye. A method of converting the wavelength of the part to green or red and emitting white is also preferable. Further, the CIE chromaticity coordinates (x, y) preferably have an x value in the range of 0.30 to 0.43 and a y value in the range of 0.27 to 0.41.

  Next, although an Example is given and this invention is demonstrated further in detail, this invention is not limited to this.

(Synthesis Example 1)
To 150 mL of pure water maintained at 300 ° C. (the pressure is about 9 MPa in the course of time), 150 mL of 0.1 mol / L sodium sulfide (Na ₂ S) aqueous solution and 0.1 mol / L zinc nitrate (Zn ( NO ₃ ) ₂ ) 150 mL of an aqueous solution was added at a constant speed over 150 minutes while stirring at 400 rpm. An outline of the reactor used for particle formation is shown in FIG. In FIG. 1, the apparatus comprises a pressure vessel 1 having a heater 3 and a pressure lid 2 and is designed to withstand a pressure of 20 MPa. There is a sample container 4 for holding a sample inside the pressure vessel, and the sample liquid in the container is stirred by the stirring device 5. The heater 3 surrounds the pressure vessel 1 in a spiral shape. The additive solution is added to the sample solution through the introduction tube 6 by a pressure resistant precision pump 7 having a pressure resistance of 30 MPa. All parts in contact with the sample solution in the reaction apparatus are made of titanium. The generated particles had an average particle size of 2.0 μm and were zinc oxide from the X-ray diffraction pattern. The X-ray diffraction peak was very sharp, indicating that the particles produced were primary particles and not nanoparticle aggregates.

(Synthesis Example 2)
Particle formation was performed in the same manner as in Synthesis Example 1 except that the reaction solution was added to 150 mL of pure water kept at 60 ° C. The generated particles had an average particle size of 0.4 μm and were zinc sulfide from the X-ray diffraction pattern. Moreover, the peak of X-ray diffraction was very broad, indicating that the generated particles were secondary particles and were aggregates of nanoparticles.

(Synthesis Example 3)
Particle formation was carried out in the same manner as in Synthesis Example 1 except that the reaction solution was added to 150 mL of a 0.1 mol / L Na ₂ S aqueous solution maintained at 300 ° C. (the pressure was about 9 MPa in the course of course). The generated particles had an average particle size of 0.8 μm, and were zinc sulfide having a senzinc crystal structure from an X-ray diffraction pattern. Moreover, the peak of X-ray diffraction was very sharp, indicating that the generated particles were primary particles and not nanoparticle aggregates.

(Synthesis Example 4)
Using the reaction device of FIG. 1, 300 ° C. (pressure approximately 9MPa at consequences) in Na ₂ S aqueous solution 150mL of 0.1 mol / L was maintained at a Na ₂ S solution 150mL of 0.1 mol / L 0 150 mL of a mixed solution of 1 mol / L Zn (NO ₃ ) ₂ aqueous solution and 0.05 mol / L ethylenediaminetetraacetic acid tetrasodium aqueous solution was added simultaneously at a constant speed over 150 minutes with stirring at 400 rpm. The generated particles had an average particle size of 2.0 μm and were zinc sulfide having a senzinc crystal structure from an X-ray diffraction pattern. The peak of X-ray diffraction was very sharp, indicating that the generated particles were primary particles and not nanoparticle aggregates.

  The characteristics of the particles produced in Synthesis Examples 1 to 4 are summarized in Table 1. The average particle size of the particles was determined from the SEM photograph of the particles, the crystal structure was determined from the X-ray diffraction pattern, and the primary particles and the secondary particles (aggregates) were discriminated by the half width of the X-ray diffraction peak.

  From Table 1, it can be seen that the inorganic semiconductor primary particles of μm class can be formed by the production method of the present invention.

(Preparation of fine particle solution A)
A solution prepared by dissolving 5 g of gelatin in 100 mL of pure water was placed in a three-necked flask, and 150 mL of a 0.1 mol / L Na ₂ S aqueous solution and 150 mL of a 0.1 mol / L Zn (NO ₃ ) ₂ aqueous solution were stirred at 50 ° C. At the same time, the mixture was rapidly added to prepare a zinc sulfide fine particle solution A. The average particle size of the generated fine particles was 18 nm.

(Preparation of fine particle solution B)
A solution prepared by dissolving 2 g of gelatin in 100 mL of pure water was placed in a three-necked flask, and 150 mL of a 0.1 mol / L Na ₂ S aqueous solution and 150 mL of a 0.1 mol / L Zn (NO ₃ ) ₂ aqueous solution were stirred at 80 ° C. At the same time, the mixture was rapidly added to prepare a zinc sulfide fine particle solution B. The average particle size of the generated fine particles was 40 nm.

(Synthesis Example 5)
Using the reaction device of FIG. 1, the Na ₂ S aqueous solution 150mL of 0.1 mol / L Temperature 300 ° C. (pressure approximately 9 MPa) was maintained at a Na ₂ S aqueous solution 15mL of 0.1 mol / L 0. 15 mL of 1 mol / L Zn (NO ₃ ) ₂ aqueous solution was simultaneously added at a constant rate for 10 minutes while stirring at 400 rpm. Subsequently, 360 mL of the fine particle solution A was slowly added at a constant rate over 360 minutes. The generated particles had an average particle size of 2.0 μm and were zinc sulfide having a senzinc crystal structure from an X-ray diffraction pattern. The peak of X-ray diffraction was very sharp, indicating that the generated particles were primary particles and not agglomerates of fine particles.

(Synthesis Example 6)
Using the reaction device of FIG. 1, the Na ₂ S aqueous solution 150mL of 0.1 mol / L Temperature 300 ° C. (pressure approximately 9 MPa) was maintained at a Na ₂ S aqueous solution 15mL of 0.1 mol / L 0. While stirring, 15 mL of 1 mol / L Zn (NO ₃ ) ₂ aqueous solution was simultaneously added at a constant rate for 2 minutes. After maintaining at 300 ° C. for 1 hour, 180 mL of the fine particle solution A was added at a constant rate for 180 minutes, and then 180 mL of the fine particle solution B was added at the primary acceleration for 120 minutes. After completion of the addition, the temperature was further maintained at 300 ° C. for 1 hour. The generated particles had an average particle diameter of 5.0 μm, and the X-ray diffraction pattern showed that the generated particles were zinc sulfide having a senzinc crystal structure and were primary particles.

(Synthesis Example 7)
Using the reactor shown in FIG. 1, 50 mL of the fine particle solution B was added to 150 mL of a 0.1 mol / L Na ₂ S aqueous solution maintained at a temperature of 300 ° C. (pressure was about 9 MPa) and held at 300 ° C. for 1 hour. Subsequently, 350 mL of the fine particle solution A was added at a primary acceleration for 180 minutes while stirring. After completion of the addition, the temperature was further maintained at 300 ° C. for 3 hours. The generated particles had an average particle size of 1.0 μm, and the X-ray diffraction pattern showed that the generated particles were primary sulfide particles with zinc sulfide having a senzinc crystal structure.

(Synthesis Example 8)
Using the reaction device of FIG. 1, the Na ₂ S aqueous solution 150mL of 0.1 mol / L Temperature 300 ° C. (pressure approximately 9 MPa) was maintained at a Na ₂ S aqueous solution 15mL of 0.1 mol / L 0. 15 mL of a mixed solution of 1 mol / L Zn (NO ₃ ) ₂ aqueous solution and 0.05 mol / L ethylenediaminetetraacetic acid tetrasodium aqueous solution was simultaneously added at a constant rate for 30 minutes while stirring. Subsequently, 360 mL of the fine particle solution A was slowly added over 300 minutes. The generated particles had an average particle size of 3.0 μm, and the X-ray diffraction pattern showed that the generated particles were primary particles with zinc sulfide having a senzinc crystal structure.

(Synthesis Example 9)
The synthesis was performed in the same manner as in Synthesis Example 5 except that a 0.1 mol / L aqueous solution of tetrasodium ethylenediaminetetraacetate was added at the same time when the fine particle solution A was added. The generated particles had an average particle size of 4.0 μm, and the X-ray diffraction pattern showed that the generated particles were primary particles with zinc sulfide having a senzinc crystal structure.

(Synthesis Example 10)
Experiments were conducted according to the prescription in Synthesis Example 3 using the stirrer shown in FIG. 3 described in Japanese Patent Publication No. 55-10545. As a result, primary particles of zinc sulfide having a senzinc structure of 0.6 μm were successfully obtained.

(Synthesis Example 11)
Experiments were conducted according to the prescription in Synthesis Example 3 using the stirrer shown in FIG. 6 described in Japanese Patent Publication No. 55-10545. As a result, primary particles of zinc sulfide having a senzinc structure of 0.9 μm were successfully obtained.

(Synthesis Example 12)
In the formulation of Synthesis Example 4, the solution was added while accelerating the addition rate of the solution to be added to the upper limit of the critical growth rate of the particles (the rate at which renucleation was not generated) to produce particles. As a result, primary particles of zinc sulfide having a senzinc structure of 2.5 μm were successfully obtained.

(Synthesis Example 13)
In the formulation of Synthesis Example 5, instead of the zinc sulfide fine particle solution A, 150 mL of a solution containing 0.1 mol / L Na ₂ S aqueous solution and 5 wt% low molecular weight gelatin at 50 ° C. and 0.1 mol / L Using a zinc sulfide fine particle solution C (average particle size of fine particles: 10 nm) prepared by mixing 150 mL of an aqueous solution of Zn (NO ₃ ) _{2 with} a mixer described in Japanese Patent Publication No. 7-23218, it is added immediately after preparation. The experiment was conducted. As a result, primary particles of zinc sulfide having a senzinc structure of 4.0 μm were successfully obtained.

(Synthesis Example 14)
Using the reaction device of FIG. 1, 300 ° C. (pressure approximately 9MPa at consequences) in Na ₂ S aqueous solution 150mL of 0.1 mol / L was maintained at a Na ₂ S aqueous solution 15mL of 0.1 mol / L 0 .15 mL of 1 mol / L Zn (NO ₃ ) ₂ aqueous solution was simultaneously added at a constant rate for 15 minutes while stirring. Subsequently, 15 mL of a 0.1 mol / L Na ₂ S aqueous solution, 0.1 mol / L Zn (NO ₃ ) ₂ , 0.0005 mol / L Cu (NO ₃ ) _2, and 0.0005 mol / L 135 mL of an aqueous solution mixed with tetrasodium ethylenediaminetetraacetate was simultaneously added at a constant rate for 135 minutes while stirring. The obtained particles were repeatedly washed with water until the conductivity of the centrifuged supernatant became 100 μS or less. Then, 10 times the amount of 1 mm glass beads was added to the particle-containing solution, and the mixture was slowly stirred at 40 rpm for 48 hours. Subsequently, the glass beads were removed with a sieve, the particles were separated by centrifugation, the particles were treated with a KCN solution, washed with water and dried to obtain phosphor powder.

(Synthesis Example 15)
In the formulation of Synthesis Example 14, the solution to be added in the second stage is 15 mL of 0.1 mol / L Na ₂ S aqueous solution, 0.1 mol / L Zn (NO ₃ ) ₂ , 0.0005 mol / L CuCl. _The procedure was the same except that the solution was changed to 135 mL of an aqueous solution mixed with ₂ and 0.0005 mol / L tetrasodium ethylenediaminetetraacetate.

(Synthesis Example 16)
In the formulation of Synthesis Example 14, the solution to be added in the second stage is 15 mL of a 0.1 mol / L Na ₂ S aqueous solution, 0.1 mol / L Zn (NO ₃ ) ₂ , 0.0005 mol / L Cu. The procedure was the same except that the solution was changed to 135 mL of an aqueous solution in which (NO ₃ ) ₂ , 0.0005 mol / L Al (NO ₃ ) ₃ and 0.0005 mol / L tetrasodium ethylenediaminetetraacetate were mixed.

(Preparation of fine particle solution D)
In a solution of 5 g of gelatin dissolved in 100 mL of pure water, 150 mL of a 0.1 mol / L Na ₂ S aqueous solution, 0.1 mol / L Zn (NO ₃ ) ₂ , 0.0005 mol / L Cu at 50 ° C. 150 mL of an aqueous solution mixed with (NO ₃ ) ₂ , 0.0005 mol / L Al (NO ₃ ) ₃ and 0.0005 mol / L tetrasodium ethylenediaminetetraacetate was rapidly added at the same time while stirring, A fine particle solution D was prepared. The generated fine particles had an average particle size of 25 nm.

(Synthesis Example 17)
Using the reaction device of FIG. 1, the Na ₂ S aqueous solution 150mL of 0.1 mol / L Temperature 300 ° C. (pressure approximately 9 MPa) was maintained at a Na ₂ S aqueous solution 15mL of 0.1 mol / L 0. While stirring, 15 mL of 1 mol / L Zn (NO ₃ ) ₂ aqueous solution was simultaneously added at a constant rate for 15 minutes. After maintaining at 300 ° C. for 1 hour, 360 mL of the fine particle solution D was added at a constant rate for 300 minutes. After completion of the addition, the temperature was further maintained at 300 ° C. for 3 hours. The obtained particles were repeatedly washed with water until the electric conductivity of the filtrate reached 100 μS or less by ultrafiltration. Then, 10 times the amount of 1 mm glass beads was added to the particle-containing solution, and the mixture was slowly stirred at 40 rpm for 48 hours. Subsequently, the glass beads were removed with a sieve, the particles were separated by centrifugation, the particles were treated with a KCN solution, washed with water and dried to obtain phosphor powder.

  The characteristics of the particles produced in Synthesis Examples 14 to 17 are summarized in Table 2. The average particle size of the particles was determined from the SEM photograph of the particles, the crystal structure was determined from the X-ray diffraction pattern, and the primary particles and the secondary particles (aggregates) were discriminated by the half width of the X-ray diffraction peak. Further, the incorporation rate of Cu into the particles was analyzed by ashing the particle powder with concentrated nitric acid and dissolving in pure water, and using an ICP analysis method.

  Using the zinc sulfide particles of Synthesis Examples 14 to 17, EL elements were prepared and the light emission characteristics were evaluated. In addition, the viscosity of each coating liquid is under stirring (rotation speed: 20 rpm) using a viscometer (VISCONIC ELD.R and VISCOMETER CONTROLLER E-200 Rotor No. 71, manufactured by Tokyo Keiki Co., Ltd., both trade names). , And measured at a liquid temperature of 16 ° C.

(Preparation of phosphor coating solution)
Zinc sulfide EL phosphors of Synthesis Examples 14 to 17 and cyanoresin (trade name: CR-S, manufactured by Shin-Etsu Chemical Co., Ltd.) as a binder were added to a DMF organic solvent at the following composition ratio, and a propeller mixer (rotation speed: 3000 rpm). An EL phosphor particle-containing coating solution having a viscosity at 16 ° C. of 0.5 Pa · s was prepared.
-Zinc sulfide EL phosphors of Synthesis Examples 14 to 17: 100 parts by weight-Cyanoresin: 25 parts by weight

(Preparation of coating solution containing dielectric fine particles)
Barium titanate (made by Cabot Specialty Chemicals, trade name, BT-8: average particle size 120 nm) as dielectric fine particles and cyanoresin (trade name: CR-S, made by Shin-Etsu Chemical Co., Ltd.) as a binder in the following composition ratio are DMF. It was added to an organic solvent and dispersed with a propeller mixer (rotation speed 3000 rpm) to prepare a coating solution containing dielectric fine particles having a viscosity at 25 ° C. of 0.5 Pa · s.
・ Barium titanate ・ ・ ・ 90 parts by weight ・ Cyanoresin ・ ・ ・ ・ ・ ・ ・ ・ 30 parts by weight

(Production and evaluation of EL elements)
On a polyethylene terephthalate (thickness 100 μm) on which an ITO transparent electrode was sputtered as a support, an EL phosphor particle-containing coating solution was applied using a slide coater so that the target film thickness of the dried coating film was 20 μm. After application, the sheet-like laminate A having an EL phosphor layer formed on ITO was obtained by drying at 120 ° C. Subsequently, the sheet-like laminate A is placed again on the coating apparatus provided with the above-mentioned slide coater, and the coating solution containing dielectric fine particles is applied in the same manner as the coating of the phosphor layer so that the dry film thickness of the coating film becomes 10 μm. Thus, it apply | coated and dried and obtained the sheet-like laminated body B which laminated | stacked the EL fluorescent substance layer and the dielectric material layer on ITO. A 30 μm-thick aluminum foil is pasted on the sheet-like laminate B as a back electrode, a lead wire for supplying voltage to the transparent electrode and the back electrode is attached, and then the whole is sealed with a sealing film An EL element was obtained. When an alternating current of 100 V and 1 kHz was applied to the EL element, good light emission characteristics were exhibited.

It is outline | summary explanatory drawing of the apparatus for hydrothermal synthesis used in the Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pressure-resistant container 2 Pressure-resistant lid 3 Heater 4 Sample container 5 Stirrer 6 Introducing pipe 7 Pressure-resistant precision pump

Claims (15)

  Inorganic semiconductor primary characterized in that particles are formed by reacting at least one precursor solution in a solvent mainly composed of water in a reaction vessel set at a pressure of 0.2 to 20 MPa and a temperature of 120 to 370 ° C. Particle production method.   An inorganic phosphor characterized in that particles are formed by reacting at least one precursor solution in a solvent mainly composed of water in a reaction vessel set at a pressure of 0.2 to 20 MPa and a temperature of 120 to 370 ° C. A method for producing primary particles.   The method for producing inorganic particles according to claim 1, wherein the precursor solution is an ionic aqueous solution.   The method for producing inorganic particles according to claim 1, wherein the precursor solution is a solution containing inorganic fine particles having an average particle diameter of 1 to 50 nm. An aqueous solution containing sulfur ions and an aqueous solution containing zinc ions are added and reacted, and particles are adjusted so that the sulfur ion concentration in the reaction solution is 10 ⁻⁵ to 10 mol / L excess with respect to the zinc ion concentration 4. The method for producing inorganic particles according to claim 3, wherein the formed zinc sulfide having an average particle diameter of 0.5 to 50 [mu] m is used as a base material.   A method for producing inorganic particles according to any one of claims 1 to 5, wherein a chelating agent having an amino group or a carboxyl group is added.   The inorganic particle according to any one of claims 1 to 6, wherein at least one metal element selected from the group consisting of copper, manganese, silver, gold and rare earth elements is added as an activator. Manufacturing method.   The method for producing inorganic particles according to claim 7, wherein a metal element as an activator is added by mixing an ion solution of the metal and a chelating agent.   The inorganic substance according to any one of claims 1 to 8, wherein an ion solution of at least one element selected from the group consisting of chlorine, bromine, iodine, and aluminum is added as a coactivator. Particle production method.   An inorganic particle produced by the method according to any one of claims 1 to 9, wherein the solubility product pKsp in water at 25 ° C of the particle is in the range of 17 to 40. Semiconductor or phosphor primary particles.   An inorganic semiconductor or phosphor produced by the method according to any one of claims 1 to 9, wherein the average particle size of the particles is in the range of 0.1 to 100 µm. Primary particles.   An inorganic semiconductor or phosphor primary particle produced by the method according to any one of claims 1 to 9, wherein the particle is a metal sulfide.   An inorganic particle or phosphor primary particle produced by the method according to claim 1, wherein the particle is a metal oxide.   An inorganic particle produced by the method according to any one of claims 1 to 9, wherein the particle is a metal nitride, or an inorganic semiconductor or phosphor primary particle.   An inorganic particle or phosphor primary particle produced by the method according to any one of claims 1 to 9, wherein the particle is based on zinc sulfide.

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