JP2008089707A - Electrochromic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrochromic device which has extremely high color purity, with which colors are precisely controlled and which is most suitable as a display element for displaying a full color image. <P>SOLUTION: The electrochromic device: which has a pair of electrode structures (a display electrode structure 11 and a counter electrode structure 12) comprising at least transparent electrodes 2, 7 formed on the supporting substrates 1, 6, and disposed so as to make the transparent electrodes be opposite to each other while interposing an electrolyte layer 5 in between; which has a porous electrode having an electrochromic coloring agent 3 to develop color with oxidation or reduction reactions adsorbed thereto is formed on at least one transparent electrode of the pair of electrode structures; and which has a porous electrode 8, having a polyquinone compound 13 having at least one out of benzoquinone, naphthoquinone, and anthraquinone as its monomer adsorbed thereto, formed on the transparent electrode 7 constituting the counter electrode structure 12, is provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrochromic device excellent in response speed, color development efficiency, display color purity, capable of forming a clear and sharp image and excellent in repeated durability.

In recent years, there has been a growing demand for display dye materials and display elements using the same that are bright and excellent in color purity, consume less power, and can be easily applied to full-color display. Conventionally, CRT, LCD, PDP Many proposals have been made on light-emitting elements such as ELD.
However, since the above-mentioned various conventional light-emitting elements are used in such a manner that the user looks directly at the light emission, there is a problem that visual fatigue is caused when browsing for a long time.
In addition, mobile devices such as mobile phones are often used outdoors, and there is also a problem that the visibility is deteriorated by canceling light emission under sunlight.
Furthermore, LCD is a technology that is especially in demand among light-emitting elements, and is used in various display applications such as large and small. However, LCD has a narrow viewing angle and is easy to see. There are issues to be improved.

By the way, regarding the reflective display element, various techniques have been proposed in the past due to an increase in demand for electronic paper.
For example, a reflective LCD or an electrophoretic method can be used.
As the reflective LCD, a GH type liquid crystal system using a dichroic dye, a cholesteric liquid crystal, and the like are known. These methods have the advantage of power saving because they do not use a backlight, compared to conventional light emitting LCDs, but they have a viewing angle dependency and low light reflection efficiency, so There is a problem that the screen becomes dark.
On the other hand, the electrophoresis method is a method that utilizes a phenomenon in which charged particles dispersed in a solvent move by an electric field, and has the advantage of low power consumption and no viewing angle dependency. However, in the case of performing full color, it is necessary to apply a juxtaposed mixing method using a color filter, so that there is a problem that the reflectance is lowered and the screen is inevitably darkened.

In recent years, a device using an electrochromic (hereinafter abbreviated as EC) element has been proposed for a light control mirror, a timepiece or the like of an automobile.
Display using an EC element does not require a polarizing plate or the like, has no viewing angle dependency, is a reflective type, has excellent visibility, has a simple structure, can be easily enlarged, and can be varied depending on the selection of materials. There is an advantage that a color tone can be displayed.

As a display device using a specific EC element, there is a proposal for a display device having a structure in which a semiconductor nanoporous layer is provided on at least one of a pair of transparent electrodes and an EC dye is supported on the semiconductor nanoporous layer. (For example, refer to Patent Documents 1 and 2 and Non-Patent Documents 1 and 2.)
These display devices can be held in a static state just by forming an open circuit to block the movement of electrons between the electrodes and maintaining the oxidation-reduction state, so no power is required to maintain the display image and consumption It is excellent in that the power is extremely low.

JP 2003-248242 A JP 2003-270670 A Displays, 25 (2004) 223. J. et al. Phys. Chem. B, 104 (2000) 11449

  When the structure of the display device using various EC elements of the above-mentioned conventional publicly known documents was specifically examined, an antimony-doped tin oxide (ATO) porous electrode was provided on the transparent electrode as the counter electrode (non-patent) Document 2) and those provided with a metal oxide semiconductor porous electrode carrying a phenothiazine derivative (Patent Documents 1 and 2 and Non-Patent Document 1) have been disclosed.

However, antimony-doped tin oxide (ATO) that constitutes the counter electrode of the display device of Non-Patent Document 2 is colored dark gray as a material and is suitable as an electrode material for performing color display. It was not material.
Moreover, since the phenothiazine derivative carried on the metal oxide semiconductor porous electrode constituting the counter electrode of the display device of Patent Documents 1 and 2 and Non-Patent Document 1 has a property of red coloration by an oxidation reaction, The display electrode side has a drawback of hindering the desired color display by the EC dye.
In particular, three color layers of cyan (C), magenta (M), and yellow (Y) were laminated for the purpose of obtaining a transparent display device or for clear full-color image display. When constructing a device with a configuration, it is ideal that the counter electrode is made of a colorless and transparent material as a whole, and that the supported material does not cause a hue change due to oxidation / reduction reactions. It is.

  Therefore, in the present invention, in view of the problems of the above-described conventionally known display devices, the configuration on the counter electrode side is particularly examined, and a material that is colorless and transparent and does not cause a hue change even by an oxidation / reduction reaction. The present invention provides an electrochromic device that has a supported structure, is extremely suitable for full-color display, and is clear, has high color purity, and is excellent in repeated durability.

  In the present invention, a pair of electrode structures (display electrode structure and counter electrode structure) on which at least a transparent electrode is formed on a support substrate sandwich an electrolyte layer so that the transparent electrodes face each other. A porous electrode on which an electrochromic dye that develops color by oxidation or reduction reaction is adsorbed and formed on at least one transparent electrode of the pair of electrode structures, and the counter electrode Provided is an electrochromic device having a structure in which a porous electrode on which a polyquinone compound containing at least one of benzoquinone, naphthoquinone, and anthraquinone is adsorbed is formed on a transparent electrode constituting the structure.

  According to the present invention, a colorless and transparent material is applied as a porous electrode constituting the counter electrode structure, and a material that does not cause a hue change by an oxidation / reduction reaction is supported, so that an extremely color display as a whole is achieved. In particular, the present invention is suitable for full color applications, and has an electrochromic display device having a practically sufficient response speed and color development efficiency, high color purity and capable of precise image control.

The electrochromic device of the present invention will be specifically described with reference to the drawings.
However, the present invention is not limited to the following examples, and a conventionally known configuration can be added as appropriate, and does not depart from the gist of the present invention.

FIG. 1 shows a schematic sectional view of an example of the electrochromic device of the present invention.
The electrochromic device 10 includes a display electrode structure 11 having a structure in which a transparent electrode 2 and a porous electrode 4 on which an organic EC dye 3 made of a pyridine compound described later is supported are provided on a support substrate 1, and a support substrate. A counter electrode structure 12 having a configuration in which a transparent electrode 7 and a porous electrode 8 carrying a polyquinone compound 13 described later are supported on the electrode 6 via the electrolyte layer 5. Yes.
Hereinafter, the components will be sequentially described.

The support substrates 1 and 6 are preferably made of a material having excellent heat resistance and high dimensional stability in the planar direction. Specifically, glass materials and transparent resins can be applied, but the present invention is not limited thereto. Absent.
Examples of the transparent resin include polyethylene terephthalate, polyethylene naphthalate, polyamide, polysulfone, polyether sulfone, polyether ether ketone, polyphenylene sulfide, polycarbonate, polyimide, polymethyl methacrylate, and polystyrene.

The transparent electrodes 2 and 7 are formed by laminating a transparent electrode layer on a predetermined transparent substrate.
Examples of the material for forming the transparent electrode layer include a mixture of In ₂ O ₃ and SnO ₂ , a so-called ITO film, and a film coated with SnO ₂ or In ₂ O ₃ .
Further, Sn, Sb, F, or the like may be doped into the ITO film or a film coated with SnO ₂ or In ₂ O ₃ , and other MgO, ZnO, or the like can be applied.

The porous electrode 4 is preferably composed of a material having a large surface area in order to ensure a high supporting function of the organic EC dye described later. Examples thereof include a porous shape having fine pores on the surface and inside, a lot shape, a wire shape, a mesoporous shape, and an aggregated particle shape.
The porous electrode 4 is made of metal, various semiconductor materials, and a conductive polymer.
Examples of the oxide semiconductor include TiO ₂ , SnO ₂ , Fe ₂ O ₃ , SrTiO ₃ , WO ₃ , ZnO, ZrO ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , V ₂ O ₅ , In ₂ O ₃ , Examples thereof include CdO, MnO, CoO, TiSrO ₃ , KTiO ₃ , Cu ₂ O, sodium titanate, barium titanate, and potassium niobate.
Examples of the complex oxide semiconductor include SnO ₂ —ZnO, Nb ₂ O ₅ —SrTiO ₃ , Nb ₂ O ₅ —Ta ₂ O ₅ , Nb ₂ O ₅ —ZrO ₂ , Nb ₂ O ₅ —TiO ₂ , Ti _{-SnO 2, Zr-SnO 2,} Sb-SnO 2, Bi-SnO 2, In-SnO 2 and the like.
Examples of the conductive polymer include polythiophene, polypyrrole, polyacetylene, polyphenylene vinylene, and polyphenylene sulfide.
In order to finally configure the target electrochromic device for color display, the porous electrode material is optimally colorless and transparent, and among these materials, in particular, TiO ₂ , SnO ₂ , Sb -SnO ₂ and In-SnO ₂ are preferred.

Next, the organic EC dye 3 will be described.
The organic EC dye 3 is assumed to be carried on the surface of the porous electrode 4 and the internal micropores. As the organic EC dye 3, a known material can be used as an electrochromic dye. However, in order to make it adsorb | suck to the porous electrode 4 by the method mentioned later, it is preferable that the organic EC pigment | dye 3 has an adsorption group for adsorb | sucking to a porous electrode. Specific examples of the adsorbing group include an acidic group such as a carboxyl group, a sulfonic acid group, and a phosphonic acid group, an amino group, a metal alkoxide, and a metal halide. A plurality of compounds may be mixed and used.

  In FIG. 1 for explaining the present example, the organic EC dye 3 for color display is shown to be supported only on the porous electrode 4 on the display electrode structure 11 side. The configuration is not limited to the example, and the porous electrode 8 on the counter electrode structure 12 side may be supported. However, in such a case, a material that reverses the oxidation / reduction reaction in the color development / decoloration reaction of the organic EC dye is applied.

  Specific examples of the organic EC dye 3 are shown in the following formulas (6) to (19).

In the above formula, Me is a methyl group.
Of the organic EC dyes of the above formulas (6) to (19), the materials represented by the formulas (7), (8), (11), (18), and (19) are particularly excellent in color developability at a low voltage. It was confirmed that it was excellent.

Next, a method for supporting the organic EC dye on the porous electrode 4 will be described.
For example, conventionally known techniques such as a method of adsorbing on the surface of the porous electrode 4 and a method of chemically bonding the surface of the porous electrode and the organic EC dye can be applied.
As a specific method, a dry process such as a vacuum deposition method, a coating method such as spin coating, an electric field deposition method, an electric field polymerization method, a natural adsorption method immersed in a solution of a compound to be supported, and the like can be applied. A method of chemically bonding an organic EC dye to the surface of the porous electrode is preferable.

As a natural adsorption method, a solution is prepared by dissolving a predetermined organic EC dye in a predetermined solvent, and a transparent substrate on which a porous electrode 4 that has been previously dried is formed is immersed, The method of apply | coating the solution which melt | dissolved organic EC pigment | dye to the porous electrode 4 is mentioned.
In this natural adsorption method, in order to reliably adsorb the organic EC dye to the porous electrode 4, it is necessary to introduce a functional group having adsorptivity into the chemical structure of the organic EC dye.
The functional group having the adsorptivity is appropriately selected according to the material of the porous electrode 4. For example, when the porous electrode 4 is made of an oxide semiconductor, the adsorptive functional group in the chemical structure of the organic EC dye includes a phosphonic acid group, a sulfonic acid group, a carboxyl group, a hydroxy group, an amino group, etc. Is preferably introduced in advance.

  The functional group may be introduced directly into the skeleton of the chemical structure of the organic EC dye, or may be introduced by forming a bond via another predetermined functional group. Among the above, when a predetermined functional group is used, an adsorptive functional group can be introduced through, for example, an alkyl group, a phenyl group, an ester, an amide group, or the like.

  Examples of the solvent for dissolving the organic EC dye include water, alcohol, acetonitrile, propionitrile, halogenated hydrocarbons, ethers, dimethyl sulfoxide, N, N-dimethylformamide, N-methylpyrrolidone, esters, Carbonates, ketones, hydrocarbons and the like can be applied. These may be used singly or may be mixed as appropriate.

Further, when the organic EC dye is chemically bonded to the surface of the porous electrode 4, a predetermined functional group may be interposed between the surface of the porous electrode 4 and the organic EC dye skeleton. For example, functional groups such as an alkyl group, a phenyl group, an ester, and an amide can be mentioned.
Further, after the surface of the porous electrode 4 is modified with a silane coupling agent or the like, an organic EC dye may be chemically bonded and formed.
By such surface modification, when the organic EC dye forms a chemical bond with the material of the porous electrode 4, the binding force of the organic EC dye becomes stronger. This is advantageous when using a high-priced material, and the material selectivity of the organic dye is increased, and the durability of the electrochromic device is improved.

The electrolyte layer 5 has a configuration in which a supporting electrolyte is dissolved in a solvent.
Examples of the supporting electrolyte include lithium salts such as LiCl, LiBr, LiI, LiBF ₄ , LiClO ₄ , LiPF ₆ , and LiCF ₃ SO ₃ , potassium salts such as KCl, KI, and KBr, and NaCl, NaI, NaBr, and the like. And tetraalkylammonium salts such as tetraethylammonium borofluoride, tetraethylammonium perchlorate, tetrabutylammonium borofluoride, tetrabutylammonium perchlorate, and tetrabutylammonium halide.
A known redox compound may be added to the electrolyte layer 5 as necessary. As the redox substance, for example, a ferrocene derivative, a tetracyanoquinodimethane derivative, a benzoquinone derivative, a phenylenediamine derivative, or the like can be applied.
As the solvent, a solvent that dissolves the supporting electrolyte and does not dissolve the organic EC dye described above is selected.
For example, it is appropriately selected from water, acetonitrile, dimethylformamide, propylene carbonate, dimethyl sulfoxide, propylene carbonate and the like.

Further, a so-called matrix material may be applied to the electrolyte layer 5.
Matrix material can be appropriately selected depending on the purpose, for example, skeletal unit _{respectively, - (CC-O) n} -, - (CC (CH 3) -O) n -, - (CC-N ) _n- , or-(C-C-S) _n- , for example, polyethylene oxide, polypropylene oxide, polyethyleneimine, and polyethylene sulfide.
In addition, you may have a branched structure suitably by making these into a principal chain structure. Polymethyl methacrylate, polyvinylidene fluoride, polyvinylidene chloride, polycarbonate, and the like are also suitable.

The electrolyte layer 5 may be a polymer solid electrolyte layer.
In this case, it is preferable to add a predetermined plasticizer to the polymer of the matrix material.
As the plasticizer, when the matrix polymer is hydrophilic, water, ethyl alcohol, isopropyl alcohol, and a mixture thereof are preferable. When the matrix polymer is hydrophobic, propylene carbonate, dimethyl carbonate, ethylene carbonate, γ- Preferred are butyrolactone, acetonitrile, sulfolane, dimethoxyethane, ethyl alcohol, isopropyl alcohol, dimethylformamide, dimethyl sulfoxide, dimethylacetamide, n-methylpyrrolidone, and mixtures thereof.

The porous electrode 8 is made of a transparent material having a large surface area so as to enhance the function of supporting a polyquinone compound described later. For example, those having a porous shape, a lot shape, a wire shape or the like having fine pores on the surface and inside are preferable.
As a material for forming the porous electrode 8, metals, various semiconductor materials, and conductive polymers can be applied.
Examples of the oxide semiconductor include TiO ₂ , SnO ₂ , Fe ₂ O ₃ , SrTiO ₃ , WO ₃ , ZnO, ZrO ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , V ₂ O ₅ , In ₂ O ₃ , Examples thereof include CdO, MnO, CoO, TiSrO ₃ , KTiO ₃ , Cu ₂ O, sodium titanate, barium titanate, and potassium niobate. Examples of the complex oxide semiconductor include SnO ₂ —ZnO, Nb ₂ O ₅ —SrTiO ₃ , Nb ₂ O ₅ —Ta ₂ O ₅ , Nb ₂ O ₅ —ZrO ₂ , Nb ₂ O ₅ —TiO _{2. , Ti-SnO 2, Zr-} SnO 2, Sb-SnO 2, Bi-SnO 2, In-SnO 2 and the like.
In order to finally configure the target electrochromic device for color display, the porous electrode material is optimally colorless and transparent, and among these materials, in particular, TiO ₂ , SnO ₂ , Sb— SnO ₂ and In—SnO ₂ are preferable.

Next, the polyquinone compound 13 will be described.
The polyquinone compound 13 applied in the present invention is at least one of those represented by the following formulas (1), (2), (3), (4), and (5).

However, X in the above formula (5) is a hydrogen atom or an aliphatic hydrocarbon group, and Y is any one of a hydrogen atom, an aliphatic hydrocarbon group, an ether group, and a hydroxy group.
The polyquinone compound 13 is a polymer comprising a benzoquinone derivative, a naphthoquinone derivative, and an anthraquinone derivative as repeating units.
Specifically, the following polybenzoquinone (following formula (1)), polymercaptobenzoquinone (following formula (2)), poly (1,4-naphthoquinone-5,8-diyl) (following formula (3)) , Poly (anthraquinone-2,6-diyl) (following formula (4)), poly (anthraquinone-1.4-diyl) (following formula (20)), poly (2-methylanthraquinone-1,4-diyl) (Formula (21) below) and the like are suitable.

Next, a method for adsorbing the polyquinone compound to the porous electrode 8 on the counter electrode structure side will be described.
For example, various coating methods such as electrolytic polymerization, dip, spin, cast, and the like can be mentioned.
When coating, the polyquinone compound is previously dissolved in an organic solvent.
Examples of the organic solvent include water, alcohol, acetonitrile, propionitrile, halogenated hydrocarbon, ethers, dimethyl sulfoxide, N, N-dimethylformamide, N-methylpyrrolidone, chloroform, dichloromethane, methylene chloride, toluene, and tetrahydrofuran. Esters, carbonates, ketones, hydrocarbons and the like can be applied. These may be used singly or may be mixed as appropriate.

When the polyquinone compound is fixed by the electrolytic polymerization method, it can be formed as a polyquinone film by causing an oxidation reaction in an electrolytic solution in which a quinone monomer is dissolved.
In addition, since it may be in a colored state depending on the degree of progress of the polymerization reaction, it is preferable to control the degree of polymerization to ensure a colorless and transparent state.
Examples of the monomer for polymerization include compounds shown in the following (22) to (24).

Alternatively, it may be polymerized in advance and coated to be applied to the porous electrode.
In this case, various polyquinone compounds can be obtained by performing a polymerization reaction using a dihalide quinone monomer.
For example, a compound of the following formula (25) is reacted with the following formulas (26), (27), (28) in a predetermined solvent under a nitrogen atmosphere, and then an acid is added to the reaction solution to precipitate. To obtain the compound of the above formula (20).

Next, a display method of the electrochromic device 10 will be described.
The porous electrode 4 of the electrochromic device 10 of FIG. 1 carries a predetermined pyridine compound, which is an organic EC dye that does not absorb in the visible region in a steady state.
A predetermined lead wire is connected to the pair of electrode structures 11 and 12 to constitute a display device.
When a predetermined voltage is applied through the predetermined lead wire, electrons are transferred between the porous electrode 4 and the organic EC dye material carried on the porous electrode 4, and an electrochemical reduction reaction occurs in the organic EC dye, Color develops in a radical state.

The electrochromic device of the present invention is not limited to the so-called monochromatic display configuration shown in FIG. 1, and can be applied to a multicolor display configuration.
That is, an organic EC having the same structure as the electrochromic structure shown in FIG. 1 and having a radical state due to an electrochemical reaction and developing colors of magenta (M), cyan (C), and yellow (Y). By applying a dye and carrying it on a porous electrode to produce an electrode structure, and using these three layers, a laminated structure of magenta (M), yellow (Y), and cyan (C) is obtained. As a result, a full color display electrochromic device capable of reversibly performing color generation and decoloration display is obtained.

  Next, specific examples of the electrochromic device of the present invention and a comparative example thereof will be described.

[Preparation of display electrode structure]
On a support substrate 1 made of glass having a thickness of 1.1 mm, a 15 Ω / □ FTO film (transparent electrode 2) was formed in a plane.
Next, polyethylene glycol was dissolved at a rate of 5% by weight in a slurry in which 15% by weight of titanium oxide having a primary particle diameter of 20 nm was dispersed in an aqueous hydrochloric acid solution having a pH of about 1.0 to prepare a coating material. This paint was applied on the FTO film by a squeegee method.
Next, an FTO substrate on which a titanium oxide porous electrode 4 having a film thickness of 5 μm is formed by performing a drying treatment at 80 ° C. for 15 minutes on a hot plate and further sintering at 500 ° C. for 1 hour in an electric furnace. Obtained.
The FTO substrate on which the porous electrode 4 made of the titanium oxide film was formed was immersed in a 5 mM aqueous solution of the organic EC dye represented by the above formula (18) for 24 hours to adsorb the organic EC dye.
Thereafter, washing treatment and drying treatment were performed with an ethanol solution.

[Production of first counter electrode structure]
On a support substrate 6 made of glass having a thickness of 1.1 mm, a 15Ω / □ FTO film (transparent electrode 7) was formed in a plane.
Next, a polyethylene glycol was dissolved at a rate of 5% by weight in a slurry in which 15% by weight of ITO having a primary particle size of 25 nm was dispersed in an aqueous hydrochloric acid solution having a pH of about 2.0 to prepare a coating material.
This paint was applied on the FTO film by a squeegee method.
Next, drying was performed at 80 ° C. for 15 minutes on a hot plate, and further, sintering was performed at 500 ° C. for 1 hour in an electric furnace to obtain an FTO substrate on which an ITO porous electrode having a thickness of 7 μm was formed. .

(Synthesis of polyquinone compound: Formula (2) above)
2.5 g of 5-hydroxy-1,3-benzoxiathiol-2-one is prepared and dissolved in 25 ml of 2M aqueous sodium hydroxide under N ₂ gas atmosphere.
The reaction is carried out at 100 ° C. for 1 hour in an N ₂ atmosphere.
Under a N ₂ atmosphere, 2M sulfuric acid is added until carbon dioxide is produced.
Next, diethyl ether is added and stirred to collect the ether. This operation was repeated three times.
The collected ether solutions were combined and the solvent was removed, followed by crystallization with a mixed solvent of chloroform / ethyl acetate = 10: 1 to obtain mercaptohydroquinone.
Next, using the obtained mercaptohydroquinone, a polymercaptohydroquinone film was formed on the ITO porous electrode.
An ITO porous electrode was used as a working electrode, a platinum wire was used as a counter electrode, and silver / silver chloride was used as a reference electrode, and a voltage of +0.7 V was applied to carry out electrolytic oxidation polymerization of mercaptohydroquinone. The electrolytic solution Britton-Robinson buffer 50ml and (pH 7.0), with a mixture of ethanol 10ml dissolved mercapto hydroquinone 0.09 g, after electrolytic polymerization was deoxygenated by bubbling for 30 minutes with N ₂ gas For 30 minutes with stirring at room temperature.
Then, the board | substrate was dried and the methanol washing process was performed.
Next, when CV measurement was performed using the polyquinone compound film formed as described above, a clear redox wave was observed, and a polyquinone film was formed on the ITO porous electrode. It has been confirmed.

[Production of second counter electrode structure]
(Synthesis of polyquinone compound: Formula (20) above)
Under a N ₂ atmosphere, 1.8 g of bis (1,5-cyclooctadiene) nickel (0), 0.624 ml of 1,5-cyclooctadiene, and 1.032 g of 2,2-bipyridyl are dissolved in 84 ml of DMF.
1.5 g of 1,4-dichloroanthraquinone is dissolved in 20 ml of DMF, and this solution is added to the reaction solution under N ₂ atmosphere and reacted at 60 ° C. for 48 hours.
After completion of the reaction, the mixture is cooled, and the reaction solution is added dropwise to 1M hydrochloric acid to form a precipitate.
The precipitate was collected by filtration, after which the resulting solid was washed twice with 1M hydrochloric acid, then once with methanol and then three times with aqueous 50 ° C. disodium ethylenediaminetetraacetate solution, Next, it was washed with hot water at 50 ° C. and finally washed once with methanol.
The solid obtained by the above operation was dissolved in chloroform, and methanol was added dropwise to crystallize to obtain the compound of the above formula (20).
The obtained compound of the above formula (20) is dissolved in chloroform to make a 3 wt% solution, and this is spin-coated and dried at 3000 rpm for 10 seconds on the ITO porous electrode to form a film made of a polyquinone compound. The obtained electrode was obtained.

(Production of third counter electrode structure)
On a support substrate 6 made of glass having a thickness of 1.1 mm, a 15Ω / □ FTO film (transparent electrode 7) was formed in a plane.
Next, polyethylene glycol was dissolved at a ratio of 5% by weight in a slurry in which 20% by weight of antimony-doped tin oxide having a primary particle diameter of 20 nm was dispersed in water to prepare a paint.
This paint was applied on the FTO film by a squeegee method.
Next, after drying at 80 ° C. for 15 minutes on a hot plate and further sintering at 500 ° C. for 1 hour in an electric furnace, an antimony-doped tin oxide porous electrode 8 having a film thickness of 12 μm is formed. An FTO substrate was obtained.

(Fabrication of fourth counter electrode structure)
On a support substrate 6 made of glass having a thickness of 1.1 mm, a 15Ω / □ FTO film (transparent electrode 7) was formed in a plane.
Next, a coating material was prepared by dissolving polyethylene glycol at a ratio of 5% by weight in a slurry in which 15% by weight of tin oxide having a primary particle diameter of 25 nm was dispersed in an aqueous hydrochloric acid solution having a pH of about 2.0.
This paint was applied on the FTO film by a squeegee method.
Next, a FTO substrate on which a tin oxide porous electrode 8 having a thickness of 8 μm is formed by performing a drying process at 80 ° C. for 15 minutes on a hot plate, further sintering at 500 ° C. for 1 hour in an electric furnace. Obtained.
The FTO substrate on which the porous electrode 8 made of the tin oxide film was formed was immersed in a 5 mM aqueous solution of a phenothiazine derivative represented by the following formula (29) for 24 hours to adsorb the phenothiazine derivative to the tin oxide electrode.

(Preparation of solution for electrolyte layer)
As the electrolyte layer 5 forming solution, a solution obtained by dissolving 0.1 mol / L of lithium perchlorate in gamma-butyrolaclone, dehydrating and degassing was applied.

(Lamination of electrode structure)
Using the display electrode structure (substrate with a dye-adsorbed titanium oxide porous electrode) produced as described above and the first to fourth counter electrode structures, respectively, using a thermoplastic film adhesive having a thickness of 50 μm. And bonded at 90 ° C. At this time, an injection port was formed in a part so that the electrolyte solution could be injected by a process described later.

(Injection of electrolyte solution)
The electrolytic solution was injected from the injection port.
Thereafter, the injection port was sealed with an epoxy-based thermosetting resin, thereby completing an electrochromic device including electrode structures facing each other with the electrolyte layer sandwiched therebetween.
In accordance with the manufacturing process of the electrochromic device described above, different organic EC dyes supported on the porous electrode were applied to prepare sample cells of the following examples and comparative examples.

[Example 1]
The display electrode structure and the first counter electrode structure were applied to produce an electrochromic device having the configuration of FIG.
When a voltage of -1.5 V was applied between both electrodes of this electrochromic device, the color was immediately developed to cyan.
The response speed of the display change was about 180 ms, which was a sufficiently good speed for practical use.
Further, when 0.5 V was applied between the electrodes, it became transparent again immediately. The response speed of the display change was about 90 ms, which was a sufficiently good speed for practical use.
FIG. 2 shows spectra at the time of decoloring and color development. In this example, since the porous electrode constituting the counter electrode structure is made of a colorless material and the polyquinone compound to be supported is selected not to be colored by oxidation / reduction reaction, A colorless and transparent state could be obtained, and a vivid cyan color could be displayed during color development.
Furthermore, -1.5V and 0.5V were alternately applied 1 million times at 1 Hz between the display electrode and the counter electrode of the electrochromic device in this example, but even after the voltage application was repeated 1 million times. Almost no change in the initial state and spectrum shape was observed, and it was confirmed that the material had sufficiently excellent durability for practical use.

[Example 2]
The display electrode structure and the second counter electrode structure were applied to produce an electrochromic device having the configuration of FIG.
When a voltage of -1.5 V was applied between both electrodes of this electrochromic device, the color was immediately developed to cyan. The response speed for changing the display was about 160 ms, which was a sufficiently good speed for practical use.
Furthermore, when 0.5 V was applied between the electrodes, it became transparent again immediately. The response speed of the display change was about 80 ms, which was a sufficiently good speed for practical use.
FIG. 3 shows the spectrum at the time of decoloring and color development. In this example, a colorless material was used especially as the porous electrode constituting the counter electrode structure, and the polyquinone compound to be supported was selected so as not to be colored by oxidation / reduction reactions. It was possible to achieve a colorless and transparent state, and vivid cyan display could be performed during color development.
Furthermore, -1.5V and 0.5V were alternately applied 1 million times at 1 Hz between the display electrode and the counter electrode of the electrochromic device in this example, but even after the voltage application was repeated 1 million times. Almost no change in the initial state and spectrum shape was observed, and it was confirmed that the material had sufficiently excellent durability for practical use.

[Comparative Example 1]
The display electrode structure and the third counter electrode structure were applied to produce an electrochromic device having the configuration shown in FIG.
When a voltage of -1.5 V was applied between the electrodes of this electrochromic device, the color developed in dull cyan.
The display change response speed was about 130 ms.
Furthermore, when 0.5 V was applied between the electrodes, it became transparent again immediately. The response speed of the display change was about 60 ms.
FIG. 4 shows spectra at the time of decoloring and color development. This confirms that it is not completely colorless and transparent even at the time of decoloring. This is because antimony-doped tin oxide, which is a porous electrode material constituting the third counter electrode structure, is a material colored gray. Therefore, when the color was developed, it was displayed in a dull cyan color, and the original color development of the EC dye could not be expressed.

[Comparative Example 2]
The display electrode structure and the fourth counter electrode structure were applied to produce an electrochromic device having the configuration of FIG.
When a voltage of -1.5 V was applied between the electrodes of this electrochromic device, the color developed blue. The display change response speed was about 280 ms.
Furthermore, when 0.5 V was applied between the electrodes, it became transparent again immediately. The response speed of the display change was about 160 ms.
FIG. 5 shows the spectrum at the time of decoloring and color development. According to this, it is confirmed that the element is almost colorless and transparent at the time of decoloring.
However, when the coloring operation is performed, the phenothiazine derivative carried on the porous electrode of the counter electrode structure develops color, which is mixed with the coloring of the organic EC dye, so that it is displayed in blue as a whole. The coloring of the EC dye could not be expressed.

  As is clear from the above, according to the present invention, by forming a film made of a polyquinone compound on the porous electrode constituting the counter electrode structure, it is ensured that substantially colorless and transparent is ensured at the time of decoloring. On the other hand, a sharp target color can be displayed at the time of color development, and reversible color erasing display can be performed with high stability. Especially, it is an optimal electrochromic device for application to full color. I was able to provide it.

1 shows a schematic cross-sectional view of an example of an electrochromic device of the present invention. The transmission spectrum at the time of color development and decoloring of Example 1 is shown. The transmission spectrum at the time of color development and decoloring of Example 2 is shown. The transmission spectrum at the time of coloring and decoloring of Comparative Example 1 is shown. The transmission spectrum at the time of coloring and decoloring of Comparative Example 2 is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,6 ... Support substrate, 2 ... Transparent electrode, 3 ... Organic EC pigment | dye, 4,8 ... Porous electrode, 5 ... Electrolyte layer, 10 ... Electrochromic device, 11 ... Display electrode structure 12 ... Counter electrode structure 13 ... Polyquinone compound

Claims (3)

A pair of electrode structures (a display electrode structure and a counter electrode structure) in which at least a transparent electrode is formed on a support substrate,
It is arranged with the electrolyte layer sandwiched so that the transparent electrodes face each other,
On at least one transparent electrode of the pair of electrode structures,
A porous electrode is formed on which an electrochromic dye that develops color by oxidation or reduction reaction is adsorbed,
On the transparent electrode constituting the counter electrode structure,
An electrochromic device characterized in that a porous electrode is formed on which a polyquinone compound containing at least one of benzoquinone, naphthoquinone, and anthraquinone as a monomer is adsorbed. The electrochromic device according to claim 1, wherein the polyquinone compound is composed of at least one of the following formulas (1) to (5).

In the above formula (5), X represents a hydrogen atom or an aliphatic hydrocarbon group, and Y represents any one of a hydrogen atom, an aliphatic hydrocarbon group, an ether group, and a hydroxy group. To do.   3. The electrochromic according to claim 1, wherein the porous electrode is formed of a metal, a semiconductor material, or a conductive polymer in a mesoporous shape, an aggregated particle shape, a lot shape, or a wire shape. apparatus.

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