JP2016133648A - Electrochromic device and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrochromic device with no coloring unevenness and excellent in response speed.SOLUTION: An electrochromic device includes: a first electrode layer formed on a first substrate; a second electrode layer formed on a second substrate arranged to face the first electrode layer; an electrolyte layer formed between the first electrode layer and the second electrode layer; and an electrochromic layer arranged so as to abut on one of the first electrode layer and the second electrode layer. The electrochromic device further includes an auxiliary electrode made of a material whose resistance is lower than the electrode layer on a side having the electrochromic layer, so that the auxiliary electrode abuts on the electrode layer on the side having the electrochromic layer. The auxiliary electrode is embedded in a surface of the substrate on the side having the electrochromic layer. A smooth surface is composed by the surface of the auxiliary electrode and the surface of the substrate on the side having the electrochromic layer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrochromic device and a method for manufacturing the same.

  A phenomenon in which a redox reaction occurs reversibly and a color changes reversibly by applying a voltage is called electrochromism. The electrochromism is generally formed between two electrodes facing each other, and performs an oxidation-reduction reaction in a configuration in which an ion-conductive electrolyte is filled between the electrodes. When a reduction reaction occurs in the vicinity of one of the two electrodes facing each other, an oxidation reaction that is a reverse reaction occurs in the vicinity of the other electrode. In such an electrochromic element, in order to obtain a transparent display device, it is necessary to be made of a material having a colorless and transparent state.

  Since the electrochromism is an electrochemical phenomenon, the resistance value of the electrode affects the response speed of the electrochromic device. By reducing the resistance value of the electrode, the response of the electrochromic element can be increased in speed, and the voltage drop when the area of the electrochromic element is increased can be suppressed.

  Patent Document 1 proposes to provide a thin metal layer or metal paste layer having higher conductivity than the display electrode pattern so as to surround and touch the periphery of the display electrode pattern. However, since the structure surrounds the periphery of the display electrode pattern, the effect is low in increasing the voltage drop and the response speed inside the display pattern when responding at high speed. In addition, there is a description that it is effective to provide a mesh-like conductive layer within the display pattern so as not to impair the quality. However, there is no specific example and it is not feasible.

  Patent Document 2 proposes an electrochromic element in which a highly conductive layer is partially provided in contact with or inside a transparent electrode. However, the good conductive layer of Patent Document 2 is defined in width and thickness, and the good conductive layer as defined can be visually recognized, and the transparency is significantly lowered. Furthermore, since the pattern of the good conductive layer exists as irregularities, the thickness of the electrochromic layer changes according to the pattern. If the thickness of the electrochromic layer is a uniform electrochromic layer, the thickness of the electrochromic layer is proportional to the absorbance. Expressed as unevenness).

  Patent Document 3 proposes disposing a metal grid electrode on a transparent conductive film. When unevenness according to the metallic grid electrode is present on the surface of the transparent electrode film, the thickness unevenness of the electrochromic layer according to the pattern of the metallic grid electrode is generated as in Patent Document 2. . On the other hand, in the proposed numerical range, there is a combination in which the surface of the transparent electrode film is smooth and smooth. For example, the grid electrode thickness is 1 μm and the transparent electrode film is 1 μm or more. However, it is not realistic that the thickness of the transparent electrode film exceeds 1 μm, and the transparency of the transparent electrode film exceeding 1 μm is significantly reduced.

Therefore, the present situation is that an electrochromic element having no uneven coloring and excellent response speed has not been provided.
SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to solve the conventional problems and achieve the following object. That is, an object of the present invention is to provide an electrochromic device having no uneven coloring and excellent response speed.

The electrochromic device of the present invention as a means for solving the above problems includes a first electrode layer formed on a first support,
A second electrode layer formed on a second support provided to face the first electrode layer;
An electrolyte layer provided between the first electrode layer and the second electrode layer;
An electrochromic element having an electrochromic layer provided so as to be in contact with either the first electrode layer or the second electrode layer,
Having an auxiliary electrode made of a material having a lower resistance than the electrode layer on the side having the electrochromic layer so that the auxiliary electrode is in contact with the electrode layer on the side having the electrochromic layer;
The auxiliary electrode is embedded in the surface of the support on the side having the electrochromic layer, and the surface formed by the surface of the auxiliary electrode and the surface of the support on the side having the electrochromic layer is smooth .

  ADVANTAGE OF THE INVENTION According to this invention, the various problems in the past can be solved, and the electrochromic element with no coloring unevenness and excellent response speed can be provided.

FIG. 1 is a schematic sectional view showing an example of the electrochromic device of the present invention. FIG. 2 is a schematic sectional view showing another example of the electrochromic device of the present invention. FIG. 3A is a schematic cross-sectional view showing an example of a conventional electrochromic device. FIG. 3B is a partially enlarged view showing an alternate long and short dash line portion of FIG. 3A. FIG. 4 is a schematic cross-sectional view showing another example of a conventional electrochromic device.

(Electrochromic device)
The electrochromic device of the present invention includes first and second supports, first and second electrode layers, an auxiliary electrode, an electrochromic layer, and an electrolyte layer, and further if necessary. And other members.

<First support, second support>
The support is formed of a transparent material capable of supporting each layer and has a structure capable of supporting each layer, and at least the electrochromic layer described later among the surfaces of the first support and the second support. As long as the concave portion is formed on the surface of the support having the electrode layer on the side where the electrode layer is formed, the shape, structure, size, material, etc. are not particularly limited and may be appropriately selected according to the purpose. Can do.

  There is no restriction | limiting in particular as a shape of the said support body, According to the objective, it can select suitably, For example, the shape which has flat plate shape, a curved surface, etc. are mentioned.

  As the structure of the support, among the surfaces of the first support and the second support, at least the surface on the side where the electrode layer of the support on the side having the electrochromic layer is formed As long as the concave portion is formed, there is no particular limitation, and it can be appropriately selected according to the purpose.

There are no particular limitations on the width of the recesses, the depth of the recesses, the pitch of the recesses, the means for forming the recesses, etc., as long as the recesses are formed on the support and have auxiliary electrodes to be described later embedded therein. Can be appropriately selected according to the purpose.
The width of the recess is not particularly limited and may be appropriately selected depending on the purpose. From the viewpoint of not significantly reducing the aperture ratio of the support, considering that the auxiliary electrode is embedded, 5 μm to 50 μm is preferred.
There is no restriction | limiting in particular as the depth of the said recessed part, Although it can select suitably according to the objective, 0.5 micrometer-10 micrometers are preferable.
There is no restriction | limiting in particular as a pitch of the said recessed part, Although it can select suitably according to the objective, 100 micrometers-50,000 micrometers are preferable, and 500 micrometers-5,000 micrometers are more preferable.
The means for forming the recess (recess forming step) is not particularly limited and may be appropriately selected depending on the purpose. For example, a forming means using a laser, a forming means using a photolithography / etching process, a stamper And fine processing means.

In addition, the said recessed part is good also as a groove | channel shape which is a recessed strip, It is preferable to make the width | variety of the transversal direction of the said groove | channel into the range of the width | variety of the said recessed part.
There is no restriction | limiting in particular as a pattern shape of the said groove | channel, According to the objective, it can select suitably, For example, from a viewpoint of the simplicity in forming the said groove | channel, a line shape, a lattice shape, etc. are mentioned.

  There is no restriction | limiting in particular as a magnitude | size of the said support body, According to the objective, it can select suitably.

  As the material of the support, it is sufficient if it is transparent, and a well-known organic material or inorganic material can be used as it is. In addition, resin substrates such as polycarbonate resin, acrylic resin, polyethylene, polyvinyl chloride, polyester, epoxy resin, melamine resin, phenol resin, polyurethane resin, and polyimide resin can be used.

  The surface of the support may have a transparent insulating layer, a UV cut layer, an antireflection layer, etc. in order to improve water vapor barrier properties, gas barrier properties, ultraviolet resistance, and visibility.

<First electrode layer, second electrode layer>
The material for the first electrode layer and the second electrode layer is not particularly limited as long as it is a transparent material having conductivity, and can be appropriately selected according to the purpose. For example, indium oxide doped with tin (Hereinafter referred to as “ITO”), tin oxide doped with fluorine (hereinafter referred to as “FTO”), tin oxide doped with antimony (hereinafter referred to as “ATO”), zinc oxide, and other inorganic materials. Can be mentioned. Among these, InSnO, GaZnO, SnO, In ₂ O ₃ and ZnO are preferable.
In addition, carbon nanotubes with transparency and other highly conductive non-permeable materials such as Au, Ag, Pt, and Cu are formed in a fine network to improve conductivity while maintaining transparency. An electrode may be used.

The thickness of each of the first electrode layer and the second electrode layer is adjusted so that an electric resistance value necessary for the oxidation-reduction reaction of the electrochromic layer is obtained.
When ITO is used as a material for the first electrode layer and the second electrode layer, the thickness of each of the first electrode layer and the second electrode layer is preferably, for example, 50 nm or more and 500 nm or less. .

As a manufacturing method of each of the first electrode layer and the second electrode layer, for example, a vacuum deposition method, a sputtering method, an ion plating method, or the like can be used.
There is no particular limitation as long as each material of the first electrode layer and the second electrode layer can be formed by coating. For example, spin coating method, casting method, micro gravure coating method, gravure coating method, bar coating Method, roll coating method, wire bar coating method, dip coating method, slit coating method, capillary coating method, spray coating method, nozzle coating method, gravure printing method, screen printing method, flexographic printing method, offset printing method, reverse printing method Various printing methods such as an inkjet printing method can be used.

<First auxiliary electrode, second auxiliary electrode>
Of the first auxiliary electrode and the second auxiliary electrode, at least the auxiliary electrode on the side having the electrochromic layer is embedded in the support on the side having the electrochromic layer, and has the electrochromic layer If the surface formed by the surface of the support on the side having the electrochromic layer together with the auxiliary electrode on the side having the electrochromic layer is smooth so as to be flush with the surface of the support on the side, the material thereof, There is no restriction | limiting in particular in a formation method etc., According to the objective, it can select suitably. Further, similarly to the auxiliary electrode on the side having the electrochromic layer, the auxiliary electrode on the side not having the electrochromic layer is embedded in a support on the side not having the electrochromic layer, and the electrochromic layer The surface formed by the surface of the support that does not have the electrochromic layer together with the auxiliary electrode that does not have the electrochromic layer is smooth so that it is flush with the surface of the support that does not have the electrochromic layer. May be.

  The average step between the surface of the auxiliary electrode and the surface of the support having the electrochromic layer is preferably 50 nm or less. When the average step is 50 nm or less, a smooth electrochromic layer can be formed.

  The material of the auxiliary electrode is not particularly limited as long as it has excellent electrical conductivity, and can be appropriately selected according to the purpose. For example, silver paste, copper paste, silver ink, copper ink, low resistance metal ( Gold, silver, copper, aluminum, nickel, tin), carbon nanotubes, and the like can be used.

  There is no restriction | limiting in particular as an average width | variety of the said auxiliary electrode, Although it can select suitably according to the objective, 5 micrometers-50 micrometers are preferable from a viewpoint which does not reduce the aperture ratio of the said support body remarkably. When the average width of the auxiliary electrode is 5 μm or more, the responsiveness of the electrochromic element can be improved, and when it is 50 μm or less, the visibility of the electrochromic element can be prevented from being lowered.

  There is no restriction | limiting in particular as average thickness of the said auxiliary electrode, Although it can select suitably according to the objective, 0.5 micrometer-10 micrometers are preferable from a viewpoint of the responsiveness of the said electrochromic element. When the average thickness of the auxiliary electrode is 0.5 μm or more, the responsiveness of the electrochromic element can be improved, and when it is 10 μm or less, the thickness of the electrochromic element can be suppressed.

A method for forming the auxiliary electrode (auxiliary electrode forming step) is not particularly limited as long as it can be formed in the concave portion or the groove of the support, and can be appropriately selected according to the purpose. A method of forming an electrode only at a desired site by masking a non-electrode portion using a forming method by various printing means such as printing, gravure offset printing, ink jet printing, sputtering, vapor deposition, ion plating method, After patterning the seed layer in the groove, an electrode forming method by electroless plating or electrolytic plating may be used. In the case of the electroless plating, the seed layer may be any one that can serve as a catalyst for the electroless plating, and is selected according to the type of metal to be deposited by the electroless plating and the plating solution used. For example, PdTiO ₃ · 6H ₂ or O (metal oxide hydrate) particles, it can be like used particles obtained by supporting Pd on a metal oxide such as titanium oxide. In the case of the electrolytic plating, any material can be used as long as it is conductive. For example, silver paste, copper paste, silver ink, copper ink, ITO, or the like can be used.
The auxiliary electrode is preferably formed such that the aperture ratio of the support after the auxiliary electrode is formed on the support is 90% or more, and the auxiliary electrode is 95% or more. It is more preferable to form

There is no particular limitation on the method of smoothing the surface of the support in which the auxiliary electrode is embedded together with the auxiliary electrode (surface smoothing step), and the method can be appropriately selected according to the purpose. For example, an auxiliary electrode material is formed on the patterned support with the recesses or grooves formed by an arbitrary method, and a polishing process is performed with a flat polishing machine, so that the support together with the auxiliary electrode is formed. The surface can be smoothed. The method for forming the auxiliary electrode material is not particularly limited as long as the patterned concave portion or groove is filled with the auxiliary electrode material, and can be appropriately selected depending on the purpose. A method of forming the auxiliary electrode may be used.
In addition, in the smooth surface on another support having a smooth surface, the auxiliary electrode is patterned to form a convex portion or a ridge, and the auxiliary electrode is embedded or softened. After filling the molten support, the support is cured, and the auxiliary electrode is peeled off from the other support so that the surface of the support is smoothed together with the auxiliary electrode. It is also possible. There is no particular limitation on the patterning of the auxiliary electrode, and the auxiliary electrode forming method described above may be used.

<Electrochromic layer>
The electrochromic layer is a layer containing an electrochromic material.
The electrochromic material may be either an inorganic electrochromic compound or an organic electrochromic compound. Moreover, you may use the conductive polymer known by showing electrochromism.

Examples of the inorganic electrochromic compound include tungsten oxide, molybdenum oxide, iridium oxide, and titanium oxide.
Examples of the organic electrochromic compound include viologen, rare earth phthalocyanine, and styryl.
Examples of the conductive polymer include polypyrrole, polythiophene, polyaniline, or derivatives thereof.

As the electrochromic layer, it is preferable to use a structure in which an organic electrochromic compound is supported on conductive or semiconductive fine particles. Specifically, it has a structure in which fine particles having a particle diameter of about 5 nm to 50 nm are bound to the electrode surface, and an organic electrochromic compound having a polar group such as phosphonic acid, carboxyl group, silanol group or the like is adsorbed on the surface of the fine particles. .
In the structure, since electrons are efficiently injected into the organic electrochromic compound by utilizing the large surface effect of the fine particles, a high-speed response is possible as compared with the conventional electrochromic display element. Furthermore, since a transparent film can be formed as a display layer by using fine particles, a high color density of the electrochromic dye can be obtained. Also, a plurality of types of organic electrochromic compounds can be supported on conductive or semiconductive fine particles. Furthermore, electroconductive particle can serve as electroconductivity as an electrode layer.
Specifically, polymer-based and dye-based electrochromic compounds include, for example, azobenzene, anthraquinone, diarylethene, dihydroprene, dipyridine, styryl, styrylspiropyran, spirooxazine, spirothiopyran, thioindigo. , Tetrathiafulvalene, terephthalic acid, triphenylmethane, benzidine, triphenylamine, naphthopyran, viologen, pyrazoline, phenazine, phenylenediamine, phenoxazine, phenothiazine, phthalocyanine, Examples thereof include low molecular organic electrochromic compounds such as fluoran, fulgide, benzopyran, and metallocene, and conductive polymer compounds such as polyaniline and polythiophene. These may be used individually by 1 type and may use 2 or more types together.
Among these, viologen compounds and dipyridine compounds are preferable from the viewpoint of low color development / discoloration potential and good color values. For example, dipyridine compounds represented by the following general formula (1) are more preferable.

前記一般式（１）において、Ｒ１及びＲ２は、それぞれ独立に置換基を有していてもよい炭素数１〜８のアルキル基、及びアリール基のいずれかを表し、Ｒ１及びＲ２の少なくとも一方は、ＣＯＯＨ、ＰＯ（ＯＨ）_２、及びＳｉ（ＯＣ_ｋＨ_２ｋ＋１）_３（ただし、ｋは、１〜２０を表す）から選択される置換基を有する。
前記一般式（１）において、Ｘは、一価のアニオンを表す。前記一価のアニオンとしては、カチオン部と安定に対をなすものであれば特に制限はなく、目的に応じて適宜選択することができ、例えば、Ｂｒイオン（Ｂｒ⁻）、Ｃｌイオン（Ｃｌ⁻）、ＣｌＯ_４イオン（ＣｌＯ_４ ⁻）、ＰＦ_６イオン（ＰＦ_６ ⁻）、ＢＦ_４イオン（ＢＦ_４ ⁻）などが挙げられる。
前記一般式（１）において、ｎ、ｍ、及びｌは、それぞれ独立に０、１、又は２を表す。
前記一般式（１）において、Ａ、Ｂ、及びＣは、各々独立に置換基を有してもよい炭素数１〜２０のアルキル基、アリール基、及び複素環基のいずれかを表す。 <General formula (1)>

In the general formula (1), R1 and R2 each independently represent an optionally substituted alkyl group having 1 to 8 carbon atoms and an aryl group, and at least one of R1 and R2 is , COOH, PO (OH) ₂ , and Si (OC _k H _{2k + 1} ) ₃ (wherein k represents 1 to 20).
In the general formula (1), X represents a monovalent anion. The monovalent anion is not particularly limited as long as it forms a stable pair with the cation moiety, and can be appropriately selected according to the purpose. For example, Br ion (Br ⁻ ), Cl ion (Cl ⁻ ), ClO ₄ ions (ClO ₄ ⁻ ), PF ₆ ions (PF ₆ ⁻ ), BF ₄ ions (BF ₄ ⁻ ), and the like.
In the said General formula (1), n, m, and 1 represent 0, 1, or 2 each independently.
In the said General formula (1), A, B, and C represent either the C1-C20 alkyl group, aryl group, and heterocyclic group which may have a substituent each independently.

  As the metal complex-based and metal oxide-based electrochromic compounds, for example, inorganic electrochromic compounds such as titanium oxide, vanadium oxide, tungsten oxide, indium oxide, iridium oxide, nickel oxide, and Prussian blue are used. it can.

There is no restriction | limiting in particular as electroconductive or semiconductive fine particle which carries the said electrochromic compound, Although it can select suitably according to the objective, It is preferable to use a metal oxide.
Examples of the metal oxide material include titanium oxide, zinc oxide, tin oxide, zirconium oxide, cerium oxide, yttrium oxide, boron oxide, magnesium oxide, strontium titanate, potassium titanate, barium titanate, and calcium titanate. , Calcium oxide, ferrite, hafnium oxide, tungsten oxide, iron oxide, copper oxide, nickel oxide, cobalt oxide, barium oxide, strontium oxide, vanadium oxide, aluminosilicate, calcium phosphate, aluminosilicate, etc. Is mentioned. These may be used individually by 1 type and may use 2 or more types together.
Among these, from the viewpoint of physical properties such as electrical properties and optical properties such as electrical conductivity, from titanium oxide, zinc oxide, tin oxide, zirconium oxide, iron oxide, magnesium oxide, indium oxide, and tungsten oxide. At least one selected from the above is preferable, and titanium oxide is particularly preferable from the viewpoint that a color display excellent in response speed of color development and decoloration is possible.

  The shape of the conductive or semiconductive fine particles is not particularly limited and can be appropriately selected according to the purpose. In order to efficiently carry the electrochromic compound, the surface area per unit volume (hereinafter referred to as specific surface area). ) Is used. For example, when the fine particle is an aggregate of nanoparticles, it has a large specific surface area, so that the electrochromic compound is more efficiently supported and the display contrast ratio of color development and decoloration is excellent.

  The electrochromic layer and the conductive or semiconducting fine particle layer can be formed by vacuum film formation, but are preferably applied and formed as a particle-dispersed paste from the viewpoint of productivity.

  There is no restriction | limiting in particular in the thickness of the said electrochromic layer, Although it can select suitably according to the objective, 0.2 micrometer-5.0 micrometers are preferable. When the thickness is 0.2 μm or more, the color density can be reliably obtained, and when the thickness is 5.0 μm or less, the manufacturing cost can be suppressed and the deterioration of the visibility due to coloring can be prevented. .

The electrochromic layer may be provided so as to be in contact with either the first electrode layer or the second electrode layer, or the electrochromic layer may be provided so as to be in contact with the first electrode layer. Alternatively, another electrochromic layer in contact with the second electrode layer may be provided.
As said another electrochromic layer, it is preferable that it is formed smoothly similarly to the said electrochromic layer, and may be formed with the same material and the same thickness as the said electrochromic layer, and another material. And may be formed with a thickness.

<Electrolyte layer>
The electrolyte layer is filled with an electrolyte between the first electrode and the second electrode.
Examples of the electrolyte include inorganic ion salts such as alkali metal salts and alkaline earth metal salts, quaternary ammonium salts, acids, and alkali supporting salts. Specifically, LiClO ₄ and LiBF ₄ can be used. , LiAsF ₆ , LiPF ₆ , LiCF ₃ SO ₃ , LiCF ₃ COO, KCl, NaClO ₃ , NaCl, NaBF ₄ , NaSCN, KBF ₄ , Mg (ClO ₄ ) ₂ , Mg (BF ₄ ) _{2 and the} like.

An ionic liquid can also be used as the electrolyte material. Among these, the organic ionic liquid is preferably used because it has a molecular structure showing the liquid in a wide temperature range including room temperature.
As the molecular structure of the organic ionic liquid, examples of the cationic component include imidazole derivatives such as N, N-dimethylimidazole salt, N, N-methylethylimidazole salt, and N, N-methylpropylimidazole salt; Examples thereof include pyridinium derivatives such as N-dimethylpyridinium salt and N, N-methylpropylpyridinium salt; aliphatic quaternary ammonium compounds such as trimethylpropylammonium salt, trimethylhexylammonium salt and triethylhexylammonium salt.
As the anion component, it is preferable to use a compound containing fluorine in consideration of stability in the atmosphere. For example, BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , PF ₄ ⁻ , (CF ₃ SO _2). ) ₂ N- ^{and the} like.

As the electrolyte material, it is preferable to use an ionic liquid in which the cation component and the anion component are arbitrarily combined.
The ionic liquid may be directly dissolved in any of photopolymerizable monomers, oligomers, and liquid crystal materials. If the solubility is poor, the solution may be dissolved in a small amount of solvent and mixed with any of photopolymerizable monomers, oligomers, and liquid crystal materials.
Examples of the solvent include propylene carbonate, acetonitrile, γ-butyrolactone, ethylene carbonate, sulfolane, dioxolane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,2-dimethoxyethane, 1,2-ethoxymethoxyethane, and polyethylene glycol. , Alcohols, or a mixed solvent thereof.

The electrolyte need not be a low-viscosity liquid, and can take various forms such as a gel, a polymer cross-linked type, and a liquid crystal dispersion type. By forming the electrolyte in a gel or solid form, advantages such as improved element strength and improved reliability can be obtained.
As a solidification method, it is preferable to hold the electrolyte and the solvent in the polymer resin. This is because high ionic conductivity and solid strength can be obtained. Further, the polymer resin is preferably a photocurable resin. This is because the device can be manufactured at a low temperature and in a short time as compared with the method of thinning by thermal polymerization or evaporation of the solvent.

  There is no restriction | limiting in particular in the average thickness of the electrolyte layer which consists of said electrolyte, Although it can select suitably according to the objective, 100 nm-100 micrometers are preferable.

<Other members>
There is no restriction | limiting in particular as said other member, According to the objective, it can select suitably, For example, an insulating porous layer, a deterioration prevention layer, a protective layer, etc. are mentioned.

<< Insulating porous layer >>
The insulating porous layer has a function of retaining an electrolyte while isolating the first electrode layer and the second electrode layer so as to be electrically insulated. The material of the insulating porous layer is not particularly limited as long as it is porous, and it is preferable to use an organic material or an inorganic material having high insulating properties and durability and excellent film forming properties, and a composite thereof. .
As the method for forming the insulating porous layer, for example, a sintering method (using fine pores formed between particles by partially fusing polymer fine particles or inorganic particles by adding a binder or the like), extraction, etc. Method (after forming a constituent layer with a solvent-soluble organic or inorganic substance and a binder that does not dissolve in the solvent, the organic or inorganic substance is dissolved in the solvent to obtain pores), foaming foaming method, good solvent and poor Examples include a phase change method in which a solvent is manipulated to phase-separate a mixture of polymers, and a radiation irradiation method in which various radiations are emitted to form pores.

<< Deterioration prevention layer >>
The role of the deterioration preventing layer is to perform a chemical reaction reverse to that of the electrochromic layer, and to balance the charge, the first electrode layer and the second electrode layer are corroded or deteriorated by an irreversible redox reaction. Is to suppress it. In addition, the reverse reaction includes acting as a capacitor in addition to the case where the degradation preventing layer is oxidized and reduced.
The material of the deterioration preventing layer is not particularly limited as long as it is a material that plays a role of preventing corrosion due to irreversible oxidation-reduction reaction of the first electrode layer and the second electrode layer, and is appropriately selected depending on the purpose. For example, antimony tin oxide, nickel oxide, titanium oxide, zinc oxide, tin oxide, or a conductive or semiconducting metal oxide containing a plurality of them can be used.
The deterioration preventing layer can be composed of a porous thin film that does not hinder electrolyte injection. For example, conductive or semiconductive metal oxide fine particles such as antimony tin oxide, nickel oxide, titanium oxide, zinc oxide, tin oxide, etc., for example, acrylic, alkyd, isocyanate, urethane, epoxy, phenol, etc. By fixing to the second electrode with this binder, a suitable porous thin film satisfying the electrolyte permeability and the function as a deterioration preventing layer can be obtained.

<< Protective layer >>
The role of the protective layer is unnecessary for protecting the device from external stress and chemicals in the cleaning process, preventing leakage of electrolyte, and stable operation of the electrochromic device such as moisture and oxygen in the atmosphere. For example, to prevent the entry of things.
There is no restriction | limiting in particular as thickness of the said protective layer, Although it can select suitably according to the objective, 1 micrometer-200 micrometers are preferable.
As the material for the protective layer, for example, an ultraviolet curable resin or a thermosetting resin can be used, and specific examples include acrylic, urethane, and epoxy resins.

<Application>
The electrochromic device of the present invention includes, for example, an electrochromic display, a large display plate such as a stock price display plate, a light control device such as an antiglare mirror and a light control glass, a low voltage driving device such as a touch panel key switch, and an optical switch. It can be suitably used for optical memory, electronic paper, electronic album, and the like.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiments. Note that the reference numerals such as “1” in the drawings mean the same thing.

  FIG. 1 is a schematic sectional view showing an example of the electrochromic device of the present invention. FIG. 2 is a schematic sectional view showing another example of the electrochromic device of the present invention.

  As shown in FIG. 1, the electrochromic element 10 includes a first auxiliary electrode 42 embedded in a groove 26 that is a continuous recess formed on the first support 22, and the first support 22 and the first support 22. The surface composed of one auxiliary electrode 42 is configured to be smooth. A first electrode layer 32 is formed on the surface composed of the first support 22 and the first auxiliary electrode 42, and an electrochromic layer 52 is laminated on the first electrode layer 32. A second auxiliary electrode 44 is formed on the second support 24. A second electrode layer 34 is formed on the surface composed of the second support 24 and the second auxiliary electrode 44. Then, the first electrode layer 32 on the first support 22 side and the second electrode layer 34 on the second support 24 side are formed to face each other with the electrolyte layer 60 interposed therebetween. The electrochromic element 10 of the present invention is formed.

  By smoothing the surface composed of the first support 22 and the first auxiliary electrode 42, it is possible to make the thickness of the layer to be laminated uniform. This is particularly advantageous for an electrochromic device in which the thickness of the electrochromic layer affects the color unevenness.

  In addition, as shown in FIG. 2, the second auxiliary electrode 44 is embedded in the groove 28 formed on the second support 24, and the second support electrode 24 and the second auxiliary electrode 44 are separated from each other. The structure which made the surface to become smooth may be sufficient. In this structure, the second electrode layer 34 is smoothly formed on the surface composed of the second support 24 and the second auxiliary electrode 44. As in the electrochromic element 10 shown in FIG. 1, the first electrode layer 32 on the first support 22 side and the second electrode layer on the second support 24 side through the electrolyte layer 60. 34 are formed so as to face each other, and the electrochromic element 10 of the present invention is formed.

  The electrochromic element 10 is embedded in the groove 26 of the patterned first support 22 so that the first auxiliary electrode 42 having a lower resistance than the first electrode layer 32 has a pattern. Compared with the case where the first auxiliary electrode 42 and the second auxiliary electrode 44 are not provided, the electrochromic response speed can be increased.

  Furthermore, the material of the first auxiliary electrode 42 and the second auxiliary electrode 44 is made of a material having high electrical conductivity such as metal or carbon, so that the electrochromic response speed can be improved more efficiently. it can. Further, by forming the first electrode layer 32 and the second electrode layer 34 on the entire surface, the electrochromic layer 52 and another electrochromic layer (not shown) can react uniformly in the plane. Become. Furthermore, by making the first electrode layer 32 and the second electrode layer 34 a layer containing a conductive oxide, conductive particles, or conductive carbon, not only the conductivity and transparency can be made compatible. It also functions as a protective layer for the first auxiliary electrode 42 and the second auxiliary electrode 44, and enables the electrochromic device 10 to be stabilized over a long period of time.

(Electrochromic light control member)
The electrochromic light control member of the present invention includes the electrochromic element of the present invention, and further includes other members as necessary. As said electrochromic light control member, it can be used conveniently for light control glasses, light control glass, a glare-proof mirror, etc., for example.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

Example 1
An electrochromic device having the configuration shown in FIG. 2 was fabricated and evaluated.

<Formation of first auxiliary electrode and first electrode layer on first support>
A glass substrate (40 mm × 40 mm × 0.7 mm) was prepared as a first support.
On the surface of the first support, a cross-shaped groove was patterned by a laser so as to have a width of 20 μm, a depth of 3 μm, and a pitch of 5 mm. Gold was deposited on the first support on which the cross-shaped grooves were patterned by sputtering, and then copper was deposited by electrolytic plating until the grooves were filled. The copper-plated first support was subjected to a polishing process with a flat polishing machine so that the copper was embedded as a first auxiliary electrode so that the surface was smooth on the first support. A configuration was formed.
Next, an ITO film having a thickness of about 100 nm is formed by sputtering on the first support embedded so that the produced first auxiliary electrode is smooth with the first support surface. 1 electrode layer was formed, and the 1st laminated body was obtained.

<Formation of Second Auxiliary Electrode and Second Electrode Layer on Second Support>
Similar to the first laminate, a glass substrate (40 mm × 40 mm × 0.7 mm) was prepared as the second support.
On the surface of the second support, a cross-shaped groove was patterned by a laser so as to have a width of 20 μm, a depth of 3 μm, and a pitch of 5 mm. After the gold was formed on the second support on which the cross-shaped grooves were patterned by sputtering, copper was formed by electrolytic plating until the grooves were filled. The copper-plated second support was subjected to a polishing process with a flat polishing machine so that the copper was embedded as a second auxiliary electrode so that the surface was smooth on the second support. A configuration was formed.
Next, an ITO film is formed to a thickness of about 100 nm by sputtering on the second support embedded so that the produced second auxiliary electrode is smooth with the surface of the second support. Two electrode layers were formed to obtain a second laminate.

<Formation of electrochromic layer>
A titanium oxide nanoparticle dispersion (trade name: SP210, manufactured by Showa Titanium Co., Ltd., average particle size: 20 nm) is applied onto the first electrode of the first laminate produced by a spin coating method at 120 ° C. By performing an annealing treatment for 15 minutes, a nanostructured semiconductor material composed of a titanium oxide particle film having a thickness of about 1.0 μm was formed. Next, a 2,2,3,3-tetrafluoropropanol solution containing 1.5% by mass of a compound represented by the following structural formula A as an electrochromic compound was applied to the nanostructured semiconductor material by a spin coating method. Thereafter, an annealing treatment was performed at 120 ° C. for 10 minutes to carry (adsorb) the titanium oxide particle film, thereby forming an electrochromic layer.
[Structural Formula A]

<Formation of electrolyte layer and production of electrochromic element>
An electrolyte solution having the following composition was prepared.
IRGACURE184 (manufactured by BASF Japan KK): 5 parts by mass PEG400DA (manufactured by Nippon Kayaku Co., Ltd.): 100 parts by mass 1-ethyl-3-methylimidazolium tetracyanoborate (manufactured by Merck): 50 parts by mass

30 mg of the obtained electrolyte solution was measured with a micropipette and dropped onto the electrochromic layer on the first laminate. On top of this, the second laminate was bonded to produce a bonded element.
The obtained bonded element was irradiated for 60 seconds at 10 mW by a UV (wavelength 250 nm) irradiation apparatus (SPOT CURE, manufactured by USHIO INC.). Thus, an electrochromic element was produced.

<Measurement of average step>
As the measurement of the step between the surface of the first support and the surface of the first auxiliary electrode, a stylus-type step meter (Alpha step IQ: manufactured by Yamato Scientific Co., Ltd.) is used. The step was measured and the average value was calculated to calculate the average step. Note that the step measurement value is a value after noise correction.

<Response evaluation>
A voltage of −3V was applied for 5 seconds between the first electrode layer and the second electrode layer of the electrochromic element so that the first electrode layer became negative, and color was developed. Further, a voltage of +3 V was applied for 5 seconds so that the first electrode layer became positive, and the color was erased. The responsiveness of the electrochromic device colored and decolored as described above was evaluated according to the following criteria.
〔Evaluation criteria〕
◎: Color development or decoloration is completed in 2 seconds or less ○: Color development or color erasure is completed in 2 seconds or more and 5 seconds or less ×: Color development or color erasure takes more than 5 seconds

<Transparency evaluation>
The transparency of the decolored electrochromic element was evaluated based on visibility and transmittance according to the following criteria.

<< Visibility evaluation >>
〔Evaluation criteria〕
A: The auxiliary electrode is not noticed when viewed from a distance of 30 cm.
A: Almost no auxiliary electrode can be confirmed when viewed from a distance of 30 cm.
X: The auxiliary electrode can be clearly confirmed when viewed from a distance of 30 cm.

<< Transmittance evaluation >>
An average value of transmittance at wavelengths of 400 nm to 800 nm was determined and evaluated according to the following criteria. The transmittance was measured with a USB4000 manufactured by Ocean Optics.
〔Evaluation criteria〕
◎: Transmittance is 60% or more ○: Transmittance is 50% or more and less than 60% ×: Transmittance is less than 50%

<Evaluation of uneven coloring>
The color development unevenness of the electrochromic element in the color development state was visually evaluated according to the following criteria.
〔Evaluation criteria〕
A: The color unevenness is not noticed when viewed from a distance of 30 cm.
◯: Color unevenness is hardly confirmed when viewed from a distance of 30 cm.
X: Clear color unevenness seen from a distance of 30 cm.

(Example 2)
In Example 1, a cross lattice-shaped groove is patterned on the surface of the first support with a laser so as to have a width of 5 μm, a depth of 0.5 μm, and a pitch of 5 mm, and the first auxiliary electrode has a width of 5 μm and a thickness. An electrochromic device was prepared and evaluated in the same manner as in Example 1 except that the thickness was 0.5 μm and the pitch was 5 mm.

Example 3
In Example 1, a cross-shaped groove is patterned on the surface of the first support with a laser so as to have a width of 5 μm, a depth of 10 μm, and a pitch of 5 mm, and the first auxiliary electrode has a width of 5 μm and a thickness of 10 μm. An electrochromic device was prepared and evaluated in the same manner as in Example 1 except that the pitch was 5 mm.

Example 4
In Example 1, a cross lattice-shaped groove is patterned on the surface of the first support with a laser so as to have a width of 50 μm, a depth of 0.5 μm, and a pitch of 5 mm, and the first auxiliary electrode has a width of 50 μm and a thickness. An electrochromic device was prepared and evaluated in the same manner as in Example 1 except that the thickness was 0.5 μm and the pitch was 5 mm.

(Example 5)
In Example 1, a cross-shaped lattice-shaped groove is patterned on the surface of the first support with a laser so as to have a width of 50 μm, a depth of 10 μm, and a pitch of 5 mm, and the first auxiliary electrode has a width of 50 μm and a thickness of 10 μm. An electrochromic device was prepared and evaluated in the same manner as in Example 1 except that the pitch was 5 mm.

(Comparative Example 1)
The electrochromic device shown in FIG. 3A was produced and evaluated in the same manner as in Example 1.
<Formation of auxiliary electrode and electrode layer on support>
A glass substrate (40 mm × 40 mm × 0.7 mm) was prepared as a first support.
The non-auxiliary electrode portion that does not form the auxiliary electrode on the surface of the first support is mask-protected, and after ITO is formed by sputtering, the mask is removed, and copper is 20 μm wide by electrolytic plating. It was formed to have a cross lattice shape with a wire thickness of 3 μm and a pitch of 5 mm.
An ITO film having a thickness of about 100 nm was formed on the first support on which the first auxiliary electrode was formed by sputtering to form a first electrode layer.
The second support, the second auxiliary electrode, and the second electrode layer were also formed in the same manner as described above.

<Formation of electrochromic layer>
An electrochromic layer was formed in the same manner as in Example 1 except that the dip coating method was used instead of the spin coating method.

(Comparative Example 2)
The electrochromic device shown in FIG. 3A was produced in the same manner as in Comparative Example 1, and was evaluated in the same manner as in Example 1.
It is the same as Comparative Example 1 except that the width of the first auxiliary electrode and the second auxiliary electrode is 60 μm and the line thickness is 0.3 μm.

(Comparative Example 3)
The electrochromic device shown in FIG. 3A was produced in the same manner as in Comparative Example 1, and was evaluated in the same manner as in Example 1.
The same as Comparative Example 1, except that the line width of the first auxiliary electrode and the second auxiliary electrode is 2 μm and the line thickness is 0.3 μm.

(Comparative Example 4)
The electrochromic device shown in FIG. 4 was produced and evaluated in the same manner as in Example 1.
<Formation of electrode layer on support>
A glass substrate (40 mm × 40 mm × 0.7 mm) was prepared as a first support. Without forming the first auxiliary electrode, an ITO film was formed on the first support to a thickness of about 100 nm by sputtering to form a first electrode layer.
The second support and the second electrode layer were also formed in the same manner as described above.
The rest is the same as in the first embodiment.

Table 1 shows the results of responsiveness evaluation, transparency evaluation, and color unevenness evaluation for Examples 1 to 5 and Comparative Examples 1 to 4. It was confirmed that the average steps between the surface of the first support and the surface of the first auxiliary electrode of the electrochromic devices produced in Examples 1 to 5 were 0 ± 3 nm, and all were 50 nm or less.
In Comparative Examples 1 to 3, measurement of the step is omitted because the first support including the first auxiliary electrode is not smooth. Moreover, since the comparative example 4 does not have an auxiliary electrode, the measurement of the level difference is omitted.

From the results of Table 1, it is apparent that Examples 1 to 5 can provide an electrochromic device having no evaluation item “x”, no color unevenness, and excellent response speed.
That is, as shown in FIG. 3A, when the first auxiliary electrode 42 is formed without being embedded on the first support 22, the first support is formed according to the line thickness and line width of the first auxiliary electrode 42. Convex is formed on the body 22. In particular, according to the line thickness of the first auxiliary electrode 42, the thickness in the vertical direction of the electrochromic layer 52 in the region indicated by the broken line in FIG. 3A (see FIG. 3B) increases, resulting in uneven thickness of the electrochromic layer 52. The film thickness unevenness appears as color unevenness when the electrochromic element is colored. Since the film thickness unevenness of the electrochromic layer 52 is generated according to the protrusions on the first support 22, as shown in FIG. 1, only the protrusions are eliminated and the support and the auxiliary electrode are made smooth. The color unevenness is solved.

As an aspect of this invention, it is as follows, for example.
<1> a first electrode layer formed on a first support;
A second electrode layer formed on a second support provided to face the first electrode layer;
An electrolyte layer provided between the first electrode layer and the second electrode layer;
An electrochromic element having an electrochromic layer provided so as to be in contact with either the first electrode layer or the second electrode layer,
Having an auxiliary electrode made of a material having a lower resistance than the electrode layer on the side having the electrochromic layer so that the auxiliary electrode is in contact with the electrode layer on the side having the electrochromic layer;
The auxiliary electrode is embedded in the surface of the support on the side having the electrochromic layer, and the surface formed by the surface of the auxiliary electrode and the surface of the support on the side having the electrochromic layer is smooth This is an electrochromic element.
<2> The electrochromic device according to <1>, wherein an average step between the surface of the auxiliary electrode and the surface of the support having the electrochromic layer is 50 nm or less.
<3> An auxiliary electrode made of a material having a lower resistance than the electrode layer on the side not having the electrochromic layer is in contact with the electrode layer on the side not having the electrochromic layer, and the auxiliary electrode is The surface <1 that is embedded in the surface of the support that does not have the electrochromic layer and that is formed by the surface of the auxiliary electrode and the surface of the support that does not have the electrochromic layer is <1. The electrochromic device according to any one of <2> to <2>.
<4> The electrochromic device according to any one of <1> to <3>, wherein an average width of the auxiliary electrode is 5 μm to 50 μm.
<5> The electrochromic device according to any one of <1> to <4>, wherein the auxiliary electrode has an average thickness of 0.5 μm to 10 μm.
<6> The electrochromic device according to any one of <1> to <5>, wherein a material of the auxiliary electrode is at least one selected from gold, silver, copper, aluminum, nickel, tin, and carbon. is there.
<7> The method according to any one of <1> to <6>, wherein the first electrode layer and the second electrode layer are layers containing conductive oxide, conductive particles, or conductive carbon. It is an electrochromic element.
<8> An electrochromic light control member comprising the electrochromic element according to any one of <1> to <7>.
<9> The electrochromic light control member according to <8>, wherein the electrochromic light control member is any one of light control glasses, light control glass, and an antiglare mirror.
<10> a recess forming step of forming a recess on a surface of at least one of the first support and the second support facing each other;
An auxiliary electrode forming step of forming an auxiliary electrode in the recess;
A surface smoothing step of smoothing a surface on which the auxiliary electrode is formed of at least the electrochromic layer of the first support and the second support; and
Is a method for producing an electrochromic device.

DESCRIPTION OF SYMBOLS 10 Electrochromic element 22 1st support body 24 2nd support body 26 Groove 28 Groove 32 1st electrode layer 34 2nd electrode layer 42 1st auxiliary electrode 44 2nd auxiliary electrode 52 Electrochromic layer 60 Electrolyte layer

Japanese Patent Publication No. 60-38711 JP-A-1-90422 JP 2010-14917 A

Claims (10)

A first electrode layer formed on a first support;
A second electrode layer formed on a second support provided to face the first electrode layer;
An electrolyte layer provided between the first electrode layer and the second electrode layer;
An electrochromic element having an electrochromic layer provided so as to be in contact with either the first electrode layer or the second electrode layer,
Having an auxiliary electrode made of a material having a lower resistance than the electrode layer on the side having the electrochromic layer so that the auxiliary electrode is in contact with the electrode layer on the side having the electrochromic layer;
The auxiliary electrode is embedded in the surface of the support on the side having the electrochromic layer, and the surface formed by the surface of the auxiliary electrode and the surface of the support on the side having the electrochromic layer is smooth An electrochromic device characterized by that.   The electrochromic device according to claim 1, wherein an average step between the surface of the auxiliary electrode and the surface of the support having the electrochromic layer is 50 nm or less. Having an auxiliary electrode made of a material having a lower resistance than the electrode layer on the side not having the electrochromic layer so as to be in contact with the electrode layer on the side not having the electrochromic layer;
The auxiliary electrode is embedded in the surface of the support that does not have the electrochromic layer, and the surface formed by the surface of the auxiliary electrode and the surface of the support that does not have the electrochromic layer is smooth. The electrochromic device according to claim 1.   4. The electrochromic device according to claim 1, wherein an average width of the auxiliary electrode is 5 μm to 50 μm.   5. The electrochromic device according to claim 1, wherein the auxiliary electrode has an average thickness of 0.5 μm to 10 μm.   The electrochromic device according to any one of claims 1 to 5, wherein a material of the auxiliary electrode is at least one selected from gold, silver, copper, aluminum, nickel, tin, and carbon.   The electrochromic device according to any one of claims 1 to 6, wherein the first electrode layer and the second electrode layer are layers containing a conductive oxide, conductive particles, or conductive carbon.   An electrochromic light control member comprising the electrochromic element according to claim 1.   The electrochromic light control member according to claim 8, wherein the electrochromic light control member is any one of light control glasses, light control glass, and an antiglare mirror. A recess forming step of forming a recess on a surface of at least one of the first support and the second support facing each other;
An auxiliary electrode forming step of forming an auxiliary electrode in the recess;
A surface smoothing step of smoothing a surface on which the auxiliary electrode is formed of at least the electrochromic layer of the first support and the second support; and
A method for producing an electrochromic device, comprising:

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