JP2002328401A - Electrochromic element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display capable of displaying sharp images with superior contrast which are durable even for medical diagnosis, for example. SOLUTION: The electrochromic element has two planar electrodes facing to each other and at least one electrode has a layer made of transparent conductive fine particles by binding on the face opposing to the other electrode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrochromic device having excellent display image contrast and a high display response speed.

[0002]

2. Description of the Related Art In the field of medical diagnostics, for example, radiographic image diagnosis uses radiographic films, but radiation image diagnosis using photostimulable phosphor panels has been requested in response to requests for reduction of exposure dose and digitization. There is a move to the system. This system detects radiation image information accumulated in a panel by stimulated emission by scanning of excitation light, performs photoelectric conversion processing, and reproduces the image. After confirming the reproduced image on a CRT monitor,
Diagnosis is performed on an image obtained after scanning and exposing, for example, a silver salt photothermographic material with image data. This is because the image displayed on a CRT monitor or the like is not at a level necessary for guaranteeing diagnostic performance, and eventually requires a hard copy, so that an image sufficient for diagnosis can be obtained without making a hard copy. There is a strong market need for monitors that can display.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a display capable of displaying a clear and high-contrast image that can withstand medical diagnosis. It is in.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is to provide two opposing flat electrodes, at least one of which has a layer of transparent conductive fine particles on the opposing surface by bonding. Electrochromic device, the average particle size of the fine particles is 5 nm to 10 μm, polymethyl methacrylate (PMMA), cellulose, polycarbonate, titanium oxide, silicon oxide, zinc oxide, alumina, zeolite, Sn-doped indium oxide (ITO) ), Antimony-doped tin oxide (ATO), fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide, and titanium oxide fine particles selected from fine particles coated with ITO, ATO, and FTO on the surface. Transparent conductive film, formed by fine particles and fine particles Having voids as the outer shell of the transparent conductive film, being a transparent conductive film containing an indium oxide compound or a tin oxide compound as a main component, being a transparent conductive film formed by a sol-gel method, That the fine particles or the transparent conductive film carry an electrochromic dye, that the electrochromic dye is a viologen compound, that it carries a plurality of electrochromic dyes that develop different colors, and that a voltage is applied between opposing electrodes. Is applied to precipitate silver oxide or bismuth.

Hereinafter, the present invention will be described in detail. The present invention relates to an electrochromic device utilizing a change in absorption wavelength (electrochromism phenomenon) of a substance accompanying an electrochemical redox reaction. Examples of materials (electrochromic compounds) that exhibit the electrochromic phenomenon include reduction coloring inorganic compounds such as tungsten oxide, vanadium oxide, and molybdenum oxide, iridium oxide, nickel oxide, titanium oxide, indium oxide, chromium oxide, cobalt oxide, and manganese oxide. , Oxidative coloring type inorganic compounds such as Prussian blue, nitrides such as indium nitride, tin nitride, zirconium nitride chloride, viologen dyes, anthraquinone dyes, pyrazoline dyes, phenothiazine dyes, fluoran dyes, styryl spiropyran dyes, phthalocyanines Organic dyes such as organic dyes; conductive polymer compounds such as polyaniline, polythiophene, polypyrrole, polybenzidine, and polyisothianaphthene; silver oxide deposition type; and bismuth deposition type.

Conventionally, an electrochromic compound has been used as an electrode formed on a transparent electrode, and is decomposed by a vacuum evaporation method or by heating and baking an organic metal compound to form a thin film of a corresponding metal oxide or the like. Although it is formed by the method of obtaining, it is necessary to increase the film thickness in order to obtain a sufficient optical density and contrast, and when the film thickness is increased, the response speed becomes slow, and the driving current becomes large. I will.

On the other hand, medical images for diagnosis are required to be clear and have excellent contrast. The present inventor has arrived at the present invention based on the finding that by realizing a fine structure on the electrode surface, the contrast can be improved while maintaining the response speed. The electrode of the present invention is applicable to any of the conventional electrochromic compounds, and can obtain the above-described effects. In addition, the application is not limited to medical diagnosis, and can be adopted, for example, to digital paper.

In the present invention, the flat electrode functions as an electrode, and a layer made of primary particles of fine particles is bonded on at least one of the two opposing surfaces. Therefore, those having no layer made of primary particles of fine particles themselves and made of a conductive material, those having an electrode layer laminated on at least one surface of a substrate having no conductivity, and the present invention, It includes a substrate having no conductivity and having a layer composed of primary particles of fine particles on the surface thereof and an electrode layer having a surface microstructure realized thereon. The substrate itself must have a smooth surface at room temperature, but may be deformed by stress. The electrodes used in the present invention may be transparent, opaque, or reflective. A material in which both electrodes are transparent is suitable for a display element or a light control glass, and a material in which one electrode is transparent and another is opaque is suitable for a display element. Is transparent and the other is reflective, which is suitable for an electrochromic mirror.

[0009] The transparent electrode is usually in a form in which a transparent electrode layer is laminated on a transparent substrate. Here, "transparent" means having a light transmittance of 10 to 100% in a visible light region. As the opaque electrode, (1) a metal plate,
(2) A laminate in which an electrode layer is laminated on one surface of an opaque substrate having no conductivity (a variety of non-transparent plastics, glass, wood, and stones can be used) can be exemplified.
As the reflective electrode, (1) a laminate in which a reflective electrode layer is laminated on a transparent or opaque substrate having no conductivity;
(2) a laminate in which a transparent electrode layer is laminated on one surface of a transparent substrate having no conductivity, and a reflective layer is laminated on the other surface; (3) a reflective layer is formed on a transparent substrate having no conductivity. A laminate in which a transparent electrode layer is laminated on a reflective layer, (4) a laminate in which a reflective plate is used as a substrate and a transparent electrode layer is laminated thereon, and (5) a substrate in which both a light reflective layer and an electrode layer are used. And the like, and the like.

The transparent substrate is not particularly limited. For example, a colorless or colored glass, a tempered glass, or the like, or a colorless or colored transparent resin is used. Specific examples include polyethylene terephthalate, polyethylene naphthalate, polyamide, polysulfone, polyethersulfone, polyetheretherketone, polyphenylene sulfide, polycarbonate, polyimide, polymethyl methacrylate, and polystyrene.

The material of the transparent electrode is not particularly limited, and examples thereof include a metal thin film such as gold, silver, chromium, copper, and tungsten, and a metal oxide. Examples of the metal oxide include ITO (In ₂ O ₃ —SnO ₂ ), tin oxide, silver oxide, zinc oxide, and vanadium oxide. The thickness of the electrode is usually 100 to 5,000, preferably 500 to 3,000. Further, the surface resistance (resistivity) is usually in the range of 0.5 to 500 Ω / cm ² , preferably 1 to 50 Ω / cm ² . A transparent electrode may be provided with a partially opaque electrode active material for the purpose of imparting oxidation-reduction ability, imparting conductivity, and imparting electric double layer capacitance. At this time, the applied amount is, of course, selected within a range that does not impair the transparency of the entire electrode surface. Opaque electrode active materials include, for example, copper,
Metals such as silver, gold, platinum, iron, tungsten, titanium, and lithium; organic substances having a redox ability such as polyaniline, polythiophene, polypyrrole, and phthalocyanine;
Activated carbon, carbon materials such as graphite, V ₂ O ₅ , Mn
Metal oxides such as O ₂ , NiO and Ir ₂ O ₃ or mixtures thereof can be used. Further, in order to bind them to the electrodes, various resins may be used. In order to apply the opaque electrode active material or the like to the electrode, for example, a composition comprising activated carbon fiber, graphite, acrylic resin, or the like is formed on the ITO transparent electrode in a fine pattern such as a stripe or a dot. , Gold (Au)
On the thin film, a composition comprising V ₂ O ₅ , acetylene black, butyl rubber, or the like can be formed in a mesh shape.

The reflective electrode layer means a thin film having a mirror surface and exhibiting an electrochemically stable function as an electrode. Examples of such a thin film include gold, platinum, tungsten, tantalum and rhenium. And metal films of osmium, iridium, silver, nickel, palladium and the like, and alloy films of platinum-palladium, platinum-rhodium and stainless steel. Any method can be used to form such a thin film having a mirror surface, and for example, a vacuum evaporation method, an ion plating method, a sputtering method, or the like can be appropriately employed. The substrate on which the reflective electrode layer is provided may be transparent or opaque.

The reflection plate or the reflection layer means a substrate or a thin film having a mirror surface, for example, a plate-like body of silver, chromium, aluminum, stainless steel or the like or a thin film thereof. Examples of the plate-like body in which the substrate itself has both the reflective layer and the electrode function include those having self-supporting properties among those exemplified as the reflective electrode layers.

In the electrochromic device of the present invention, an electrolyte is used between the electrodes. The electrolyte is injected into a gap provided between the electrodes sealed by a vacuum injection method, an air injection method, a meniscus method, or the like, or after forming a layer of an electrolyte substance on the electrode by a sputtering method, an evaporation method, a sol-gel method, or the like. It can be used by combining opposing electrodes or laminating by using a film-like electrolyte substance.

This electrolyte is not particularly limited as long as it can color, decolor, and change the color of the electrochromic layer, but is usually 1 × 10 ⁻⁷ S / c at room temperature.
It is preferably a substance having an ionic conductivity of at least m. The electrolyte substance is not particularly limited, and a liquid system or a gelling liquid system that can fill the pores formed by the fine particles and the electrode substrate and the fine particles can be used.

As the above-mentioned liquid system, a solution in which a supporting electrolyte such as salts, acids and alkalis is dissolved in a solvent can be used. The solvent is not particularly limited as long as it can dissolve the supporting electrolyte, but a polar solvent is particularly preferable. Specifically, water, methanol, ethanol, propylene carbonate, ethylene carbonate,
Dimethyl sulfoxide, dimethoxyethane, acetonitrile, γ-butyrolactone, γ-valerolactone, sulfolane, dimethylformamide, dimethoxyethane, tetrahydrofuran, acetonitrile, propionnitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, dimethylacetamide, methylpyrrolidinone, dimethylsulfoxide Organic polar solvents such as dioxolane, sulfolane, trimethyl phosphate, and polyethylene glycol, and the like, preferably propylene carbonate, ethylene carbonate, dimethyl sulfoxide, dimethoxyethane, acetonitrile, γ-butyrolactone, sulfolane, dioxolan, dimethylformamide, dimethoxyethane, Tetrahydrofuran, adiponitrile, methoki Acetonitrile, dimethylacetamide, methylpyrrolidinone, dimethyl sulfoxide, dioxolane, sulfolane, trimethyl phosphate, organic polar solvents such as polyethylene glycol is desirable. These can be used alone or as a mixture when used.

The salts as the supporting electrolyte are not particularly limited, and include various inorganic ion salts such as alkali metal salts and alkaline earth metal salts, quaternary ammonium salts and cyclic quaternary ammonium salts. Is LiClO ₄ , Li
SCN, LiBF ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , L
iPF ₆ , LiI, NaI, NaSCN, NaClO ₄ ,
Li such as NaBF ₄ , NaAsF ₆ , KSCN, KCl,
Alkali metal salts of Na and K, (CH ₃ ) ₄ NBF ₄ ,
(C ₂ H ₅ ) ₄ NBF ₄ , (n-C ₄ H ₉ ) ₄ NBF ₄ , (C _{2
H 5) 4 NBr, (C} 2 H 5) 4 NClO 4, (n-C 4 H 9)
Suitable examples include quaternary ammonium salts such as ₄ NCLO ₄ and cyclic quaternary ammonium salts, and the like, and mixtures thereof. The acids as the supporting electrolyte are not particularly limited, and include inorganic acids and organic acids. Specific examples include sulfuric acid, hydrochloric acid, phosphoric acids, sulfonic acids, and carboxylic acids. The alkali as the supporting electrolyte is not particularly limited, and examples thereof include sodium hydroxide, potassium hydroxide, and lithium hydroxide.

As the gelling liquid electrolyte, a viscous or gelled liquid electrolyte obtained by further adding a polymer or a gelling agent to the above liquid electrolyte can be used. The polymer used is not particularly limited, for example, polyacrylonitrile, carboxymethylcellulose, polyvinyl chloride, polyethylene oxide,
Examples include polyurethane, polyacrylate, polymethacrylate, polyamide, polyacrylamide, cellulose, polyester, polypropylene oxide, and Nafion. Further, the gelling agent is not particularly limited, oxyethylene methacrylate, oxyethylene acrylate, urethane acrylate, acrylamide,
Agar, and the like.

A known solid electrolyte may be used as long as the pores formed by the fine particles and the electrode substrate and the fine particles can be filled.

As the fine particles bound to form a layer according to the present invention, particles of PMMA, cellulose, polycarbonate, titanium oxide, silicon oxide, zinc oxide, alumina, zeolite and the like can be used. The conductive fine particles that can form an electrode film with the fine particles themselves include Sn-doped indium oxide (ITO) and antimony-doped tin oxide (A
In addition to conductive fine particles such as TO), fluorine-doped tin oxide (FTO), and aluminum-doped zinc oxide, fine particles having titanium oxide fine particles coated with ITO, ATO, or FTO can be used. In addition, the conductivity here means that the powder resistance at a pressure of 100 kg / cm ² is 0.01.
１００100 Ωcm, preferably 0.01 to 10 Ωcm.

In order to obtain the contrast improving effect of the present invention
The average particle diameter of the fine particles is preferably 5 nm to 10 μm,
More preferably, it is 20 nm to 1 μm. Also the specific surface area
Is 10 by simple BET method^-3-10^Twom^Two/ G is preferred
Preferably, more preferably, 10 ^-2-10m^Two/ G.
The shape of the fine particles can be any shape such as irregular, needle, spherical, etc.
Is used.

As the binding of the fine particles by the transparent conductive film, a sol-gel method can be adopted. For example, 1) J
own of the Ceramic Soc
iety of Japan, 102,2, p200
(1994), 2) Journal of the Ceramic Society of Japan 90, 4, p157,
3) J.I. of Non-Cryst. Solids, 8
2,400 (1986) and the like.
ATO film formation is possible. Further, a transparent conductive film is formed by a sol-gel method using a sol liquid in which non-conductive fine particles such as PMMA spherical particles are dispersed, and a conductive film can be formed on the surface of these fine particles. In this manner, by forming the pores formed by the fine particles and the electrode substrate and the fine particles as the outer shell of the transparent conductive film, the substantial surface area of the electrode can be increased.

FIG. 1 shows a model diagram of a porous electrode according to the present invention. In the figure, fine particles 1 having a conductive or transparent conductive film as an outer shell are bound to an electrode substrate 2 to form a layer, and a hole formed by the electrode substrate and the fine particles also forms a transparent conductive film as an outer shell. 3 Then, the electrolyte 4 exists in a form that also fills the pores formed by the fine particles and the electrode substrate and the fine particles.

Here, the binding of the fine particles means 0.1 g or more, preferably 1 g, when the adhesion force of the fine particle layer is measured by a continuous weighting type surface property measuring device (so-called scratch tester).
A state having the above resistance.

In the present invention, in order to configure the electrochromic device to have a desired color tone or to develop a color image, it is preferable to carry an electrochromic dye on fine particles or a transparent conductive film. Can raise viologen compounds. Also, a plurality of electrochromic dyes that develop colors different from each other may be supported.

The viologen compound is

[0027]

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Having the following structure. Here, X 1 ⁻ and X 2 ⁻ represent counter anions, which may be the same or different, and may be a halogen anion, ClO ₄ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ ,
An anion selected from CH ₃ COO ⁻ and CH ₃ (C ₆ H ₄ ) SO ₃ ⁻ is shown. Examples of the halogen anion, F ^-,
Cl ^-, Br ^-, I ^-, and the like. R ₁ and R ₂ each represent a hydrocarbon group having 1 to 20, preferably 1 to 12 carbon atoms. Such hydrocarbon groups include an alkyl group, an aralkyl group, and an aryl group, and are preferably an alkyl group or an aralkyl group. Examples of the alkyl group include a methyl group, an ethyl group, an i-propyl group, an n-propyl group, and an n-
Butyl group, t-butyl group, n-pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, lauryl group, cyclohexyl group, cyclohexylmethyl group and the like. As the aralkyl group, a benzyl group,
Phenethyl group, phenylpropyl group, tolylmethyl group,
And an ethylphenylmethyl group. General formula (1)
Specific examples of the compound represented by are N, N'-diheptylbipyridinium dibromide, N, N'-diheptylbipyridinium dichloride, N, N'-diheptylbipyridinium diperchlorate, N, N'- Diheptylbipyridinium ditetrafluoroborate, N,
N'-diheptylbipyridinium dihexafluorophosphate, N, N'-dihexylbipyridinium dibromide, N, N'-dihexylbipyridinium dichloride, N, N'-dihexylbipyridinium diperchlorate, N, N'-dihexylbipyridinium ditetra Fluoroborate, N, N'-dihexylbipyridinium dihexafluorophosphate, N, N'-dipropylbipyridinium dibromide, N, N'-dipropylbipyridinium dichloride, N, N'-dipropylbipyridinium diperchlorate, N, N′-dipropylbipyridinium ditetrafluoroborate, N, N′-dipropylbipyridinium dihexafluorophosphate, N,
N'-dibenzylbipyridinium dibromide, N,
N′-dibenzylbipyridinium diperchlorate,
N, N'-dibenzylbipyridinium ditetrafluoroborate, N, N'-dibenzylbipyridinium dihexafluorophosphate, N-heptyl-N'-benzylbipyridinium diperchlorate, N-heptyl-N'-
Benzylbipyridinium ditetrafluoroborate, N-
Heptyl-N'-benzylbipyridinium dibromide, N-heptyl-N'-benzylbipyridinium idichloride, N-heptyl-N'-methylpyridinium dibromide, N-heptyl-N'-methylpyridinium dichloride and the like. The amount of the viologen compound used for the electrolyte is not particularly limited.
0.00001 to 50% by mass, preferably 0.000%
It is about 1 to 30% by mass, more preferably about 0.001 to 10% by mass. If necessary, the viologen compound can be doped with a compound that promotes color development.

A viologen compound having a polymer structure can also be used, and examples thereof include those having the following repeating units. However, n is preferably 3 to 30
It is.

[0030]

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Examples of the viologen compound having another polymer structure include polymers or copolymers represented by the following general formulas (1) to (5).

[0032]

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In the general formulas (1) to (3), m is 1 or more.
The above integer, preferably an integer of 1 to 1000, n is 0 or more
, Preferably an integer of 0 to 1000. General formula
In (2), it is preferable that n = 0. Also,
R¹, R^{twenty one}, R^{twenty three}, R³¹Each have 1 to 20 carbon atoms and are preferred
Or a divalent hydrocarbon residue of 1 to 12 or a simple covalent bond
(Ie, directly on the polymer chain without going through the hydrocarbon residue)
A form in which a viologen group is bonded), and the hydrocarbon residue
Examples thereof include a hydrocarbon group or an oxygen-containing hydrocarbon group.
It is. Examples of the hydrocarbon group include a methylene group, ethylene
Group, propylene group, tetramethylene group, pentamethylene
Hydrocarbon group, hexamethylene group, etc., phenyle
Aromatic carbonization such as benzene, biphenylene, benzylidene, etc.
Hydrogen group and the like, and also as an oxygen-containing hydrocarbon group
Is -OCH_Two-Group, -OCH_TwoCH _Two-Group, -OCH_TwoCH
_TwoCH_TwoAn aliphatic alkoxylen group such as a group, -OCH_TwoC
H_TwoO-group, -OCH_TwoCH_TwoCH_TwoAliphatic dia such as O-group
Lucoxylene group, -O (C₆H_Four) -Group, -OCH_Two(C₆
H_Four)-Group and the like, an aryloxy group, -O (C₆H_Four)
O-group, -OCH_Two(C₆H_Four) Aromatic diali such as O- group
And a hydroxy group. X1^-, X2^-Is as defined above
It is. R^Two, R^Three, R^Four, R^{twenty two}, R^{twenty four}, R³², R³³, R
³⁴Each has 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms.
Shows hydrogen group, hetero atom-containing substituent group, and halogen atom
Examples of the hydrocarbon group include a methyl group and an ethyl group.
Groups, propyl groups, alkyl groups such as hexyl groups, phenyl
, Tolyl, benzyl, naphthyl and other aryl groups
And the like, and as the hetero atom-containing substituent, the number of carbon atoms
1 to 20, preferably 1 to 12, oxygen-containing hydrocarbon groups or
Amide group, amino group, cyano group, etc.
Examples of the hydrocarbon group include methoxy and ethoxy groups.
Aryloxy such as coxyl group, phenoxy group and toloxy
Group, carboxyl group, carboxylate group, etc.
I can do it. The compound represented by the general formula (1) is
In the case of coalescence, the copolymerization mode of the repeating unit is
, Random or alternating.

[0034]

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In the general formula (4), p represents an integer of 0 or more, preferably 0 to 20, and q represents 1 to 1000.
Indicates an integer. R ⁴¹ is the same as R ^{1 in} formula (1).

In the general formula (5), r represents an integer of 1 or more, preferably 1 to 1,000. R ⁵¹ is the same as R ^{1 in} formula (1), and R ⁵² is the same as R ^{2 in} formula (1).

Specific examples of these compounds are described, for example, in JP-A-11-183938. JP 2000
The viologen compound described in -131722 can also be used in the present invention.

It is preferable that the structure of R ₁ and R _{2 in} the above formula (Chemical Formula 1) have an adsorptive substituent such as a carboxyl group, a sulfonic acid group or a phosphoric acid group. Examples include, but are not limited to:

[0039]

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In addition, dyes having an adsorbable substituent on a styryl group as shown below can also be used.

[0041]

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Here, n is 1 to 3, preferably 1 or 2. The following are specific examples.

[0043]

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[0044]

EXAMPLES Example 1 (Preparation of Substrate 1) A liquid in which antimony-doped tin oxide fine particles (average particle size: 0.5 μm) were dispersed in a 0.5% solution of indium (III) isopropoxide in isopropanol was used. IT with a sheet resistance of 10Ω / □ by spin coating
It was applied on an O glass substrate. After treatment at 100 ° C. for 1 hour, a porous electrode having a thickness of about 3 μm was formed on the ITO glass substrate. A tungsten oxide film is formed on the porous electrode by sputtering, and a thickness of 1 μm is formed on the electrode surface.
A 00 nm tungsten oxide layer was provided.

(Preparation of Substrate 2) A 100 nm-thick iridium oxide layer was formed by sputtering on an ITO glass substrate on which a porous electrode had been formed in the same manner as in the preparation of Substrate 1.

(Preparation and Evaluation of Electrochromic Device) 0.1% by mass of a 20% by mass ethanol solution of Neoceptor SA-2 (ion conductive polymer) manufactured by Tokuyama Corporation.
Of PMMA particles (particle diameter 5 μm, spherical) were mixed and dispersed. This solution was applied to the surfaces of the substrates 1 and 2 so as to have a dry film thickness of 5 μm, and dried at 90 ° C. for 3 minutes. Substrate 1,
The electrochromic element was produced by bonding 2 and sealing. This device has a good response speed with respect to the device in which the porous electrode according to the present invention is not formed,
And very high contrast. In addition, this device developed colors at both poles and exhibited a bluish black upon superposition. Even when the color was erased, good characteristics with little residual color were exhibited.

Example 2 (Preparation of Sol A) In a 0.14 M aqueous solution of indium nitrate,
A colloidal solution of indium hydroxide was obtained by gradually adding tin chloride having a molar ratio of 14% to indium nitrate and further dropping 2M aqueous ammonia until the pH reached 8.5. The colloid particles were separated, washed, and dispersed in a 0.28 M aqueous solution of indium chloride to obtain a sol. Acetic acid corresponding to 2.7 M was added to this sol, and 0.3% by mass of polyvinyl alcohol (PVA) was further dissolved to prepare sol A.

(Preparation of Porous Electrode Substrate) Rutile-type titanium oxide fine particles (average particle diameter: 0.5 μm) coated with ATO as conductive fine particles were dispersed in sol A. Pure water is added so that the mass of the ITO film formed from the sol is 1/50 of the mass of the conductive fine particles to form a coating solution.
It was applied on an O glass substrate. After performing a pretreatment at 100 ° C. for 30 minutes, it was baked at 500 ° C. for 30 minutes to form a porous electrode having a thickness of 3 μm.

(Formation of Tungsten Oxide Layer) 8 g of tungsten powder was gradually added to 50 ml of 15% hydrogen peroxide while cooling to 0 ° C. After the reaction is completed, filtration and decomposition of excess hydrogen peroxide with a platinum catalyst,
An aqueous solution of polytungstic acid was obtained. This aqueous solution was further diluted 100 times with pure water, applied on the porous electrode, and immediately dried at 100 ° C. for 2 hours. A 100 nm thick tungsten oxide layer was formed on the electrode surface.

(Formation of Cerium Oxide Layer) A cerium oxide layer having a thickness of 100 nm was formed on the surface of another porous electrode substrate by a sputtering method.

(Electrolyte) 2% by mass of water was added to a 1M propylene carbonate solution of LiClO ₄ to form a white powder of titanium oxide and a spherical PM having a diameter of 5 μm as a spacer.
An electrolytic solution was prepared by dispersing MA (0.3% by mass).

(Preparation and Evaluation of Electrochromic Element) The above-mentioned electrolytic solution was applied on a substrate on which a tungsten oxide layer had been formed, and while the substrate on which a cerium oxide layer had been formed was adhered, defoaming and sealing were performed. This device had a good response speed and a very high contrast with respect to the device in which the porous electrode according to the present invention was not formed.

Example 3 (Preparation of porous electrode substrate) Tin oxide fine particles doped with antimony (average particle size: 0.3 μm) were dispersed in the sol A of Example 2. The mass of the ITO film formed from the sol is
Pure water was added so as to be 1/50 with respect to the mass of the conductive fine particles to form a coating liquid, and the ink jet method was used.
It was applied on an ITO glass substrate having a sheet resistance of 10Ω / □. 1
After performing a pretreatment at 00 ° C. for 30 minutes, it was baked at 500 ° C. for 30 minutes to form a porous electrode having a thickness of 3 μm.

(Formation and Evaluation of Electrochromic Layer and Device) A solution prepared by dissolving 1 g of polystyrenesulfonic acid and 1 g of viologen polymer VP-1 in 100 g of γ-butyrolactone was applied on the porous electrode substrate and dried.
0.1% by mass of spherical PMMA in 0.3M KCl aqueous solution
(Particle diameter: 5 μm) was applied, and the electrode substrate on which the cerium oxide layer of Example 2 was formed was defoamed and sealed while being bonded. This device repeated coloring and decoloring of magenta at a driving voltage of 1 V, and showed a good response speed and a very high contrast with respect to a device in which a porous electrode was not formed.

Example 4 Instead of 1 g of viologen polymer VP-1, VP-
A device was produced in the same manner as in Example 3, except that 0.33 g of each of 1, 2, and 3 was mixed and used. This element is 1
With a driving voltage of V, the coloration and decoloration of black were repeated, and the response speed was good for an element that did not form a porous electrode.
And very high contrast.

Example 5 Viologen compound V-1 (all anion components were Cl
^- ) A solution obtained by dissolving 1 g in 100 g of γ-butyrolactone was applied on the porous electrode substrate and dried. 0.3M K
An electrolytic solution obtained by mixing 0.1% by mass of spherical PMMA with a diameter of 5 μm in a Cl aqueous solution was applied, and while the electrode substrate on which the cerium oxide layer of Example 2 was formed was adhered, defoaming and sealing were performed. This device repeated coloring and decoloring of reddish purple at a driving voltage of 1 V, and showed a good response speed and a very high contrast with respect to a device in which a porous electrode was not formed.

Example 6 V-1 was replaced by 0.1 g instead of 1 g of viologen compound V-1.
A device was produced in the same manner as in Example 5, except that 5 g, 0.25 g of V-2, and 0.25 g of V-3 (each anion component was Cl ⁻ ) were used. This element repeatedly developed and erased black at a driving voltage of 1 V, and exhibited a good response speed and a very high contrast with respect to an element in which a porous electrode was not formed.

Example 7 1 g of the dye S-1 (n = 1) was converted to γ-butyrolactone 10
A solution dissolved in 0 g was applied on the porous electrode substrate and dried. 0.1 of tetrabutylammonium perchlorate.
0.1% by mass of spherical PMMA in 3M acetonitrile solution
(Particle diameter: 5 μm) was applied, and the electrode substrate on which the cerium oxide layer of Example 2 was formed was defoamed and sealed while being bonded. This device repeated red coloring and decoloring at a driving voltage of 1 V, and exhibited a good response speed and a very high contrast with respect to a device in which a porous electrode was not formed.

Example 8 While stirring a 0.1 M aqueous solution of silver nitrate, 30% aqueous ammonia was gradually added dropwise to form silver oxide to form a black liquid.
When the addition was continued, the solution became transparent and a silver ammonia complex solution was obtained. On the other hand, the porous electrode substrate prepared in Example 2 and the ITO glass substrate having a sheet resistance of 10Ω / □
m, and the ends were sealed with an epoxy-based adhesive. The silver-ammonia complex solution was injected from a partially opened injection port, defoamed, and sealed to produce an electrochromic device. This element repeatedly developed and erased black at a driving voltage of 1 V, and exhibited a good response speed and a very high contrast with respect to an element in which a porous electrode was not formed.

Example 9 An aqueous solution was prepared by dissolving in 10 mM bismuth chloride, 10 mM cupric chloride, 75 mM lithium bromide, and 0.5 M hydrochloric acid. On the other hand, the porous electrode substrate produced in Example 2 and an ITO glass substrate having a sheet resistance of 10Ω / □ were bonded together via a 0.2 mm spacer, and the ends were sealed with an epoxy adhesive. The silver-ammonia complex solution was injected from a partially opened injection port, defoamed, and sealed to produce an electrochromic device. This device repeated coloring and decoloring of black at a driving voltage of 1.5 V, and had a good response speed and a very high contrast with respect to a device in which a porous electrode was not formed.

[0061]

According to the present invention, the display by the obtained electrochromic device has excellent contrast and high response speed.

[Brief description of the drawings]

FIG. 1 is a model diagram of a porous electrode according to the present invention.

[Explanation of symbols]

 1 fine particles 2 electrode substrate 3 transparent conductive film 4 electrolyte

Claims (11)

[Claims] 1. An electrochromic device having two flat electrodes facing each other, wherein at least one of the electrodes has a layer made of transparent conductive fine particles on the facing surface by binding. 2. The fine particles have an average particle size of 5 nm to 10 μm.
The electrochromic device according to claim 1, wherein m is m. 3. The method according to claim 1, wherein the fine particles are polymethyl methacrylate (PMMA), cellulose, polycarbonate, titanium oxide, silicon oxide, zinc oxide, alumina, zeolite,
Sn-doped indium oxide (ITO), antimony-doped tin oxide (ATO), fluorine-doped tin oxide (FT
3. The electrochromic device according to claim 1, wherein the electrochromic device is selected from O), aluminum-doped zinc oxide, and titanium oxide fine particles coated with ITO, ATO, and FTO. 4. The electrochromic device according to claim 1, wherein the fine particles are bound by a transparent conductive film. 5. The electrochromic device according to claim 4, wherein pores formed between the fine particles and between the electrode substrate and the fine particles have the transparent conductive film as an outer shell. 6. The electrochromic device according to claim 4, wherein the electrochromic device is a transparent conductive film containing an indium oxide compound or a tin oxide compound as a main component. 7. The electrochromic device according to claim 4, wherein the electrochromic device is a transparent conductive film formed by a sol-gel method. 8. The method according to claim 1, wherein the fine particles or the transparent conductive film carries an electrochromic dye.
The electrochromic device according to any one of claims 1 to 7, wherein 9. The electrochromic device according to claim 8, wherein the electrochromic dye is a viologen compound. 10. The electrochromic device according to claim 8, wherein the electrochromic device carries a plurality of electrochromic dyes that emit different colors. 11. The electrochromic device according to claim 1, wherein silver oxide or bismuth is deposited by applying a voltage between the opposing electrodes.