JPS62183436A - Transparent coloring and decoloring plate - Google Patents

Abstract

PURPOSE:To thoroughly eliminate the deterioration of a counter electrode and to make a titled plate adaptable to applications such as filters as well by providing a thin Prussian blue layer on the surface of the transparent electron conductive layer of a working counter electrode and subjecting the thin layer to anodic oxidation. CONSTITUTION:In2O3 is deposited by evaporation on a transparent base body 9 to form the transparent electron conductive layer 8 and a transparent coloring and decoloring layer 7 is deposited by evaporation on a working electrode 2 by using WO3 as an essential component. A transparent active material layer 6 formed by subjecting the insoluble Prussian blue of which the essential component has the structure expressed by the formula to the anodic oxidation is provided on the working counter electrode 1 and is united to a packing 5 via an electrolyte 4. Coloration and decoloration are governed by the coloring and decoloring reaction of the working electrode when the transparent working counter electrode formed by making the Prussian blue layer colorless by the anodic oxidation and the working electrode are combined. The transparent coloring and decoloring plate which changes between the blue color of the WO3 and the colorless state is thus constituted. The deterioration of the transparent electron conductive layer is thereby not admitted at all and since the color or the light past such combined plate is governed only by the reaction of the working electrode, said plate is widely usable for application for filters for attenuation, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an improvement in the counter electrode of a display electrode that can be applied to electrochromic display elements (devices) and filters.

BACKGROUND OF THE INVENTION Typical examples of display devices that utilize this type of electrochromic reaction include digital displays for watches, and filters such as light-reducing plates that can be arbitrarily controlled to add or remove color. The construction method of the electroclock reaction application device to be applied is basically the same, and has the following construction. That is, WO3tMo○3. is applied to a transparent substrate having a transparent electron conductive layer made of WO3tMo○3. The working electrode is an electrode with a transparent colored layer such as Prussian blue deposited or plated, and the counter electrode is a transparent electrode from which only the working electrode or coloring layer has been removed.The electrolyte is acetonitrile in which lithium perchlorate is dissolved. It had a structure in which a color-forming material was dissolved in an aqueous sulfuric acid solution and gelled with glycerin, and then sealed and integrated to form the desired form. For actual display purposes, a voltage is applied between the working electrode and the counter electrode, and the coloring characteristics of the working electrode are utilized. Depending on the intended use, the basic structure and materials will vary slightly, but in any case, the basic structure will not change.

This conventional basic configuration has the following problems. That is, when a voltage is applied between the working electrode and the counter electrode, an electrochemical reaction at the working electrode causes a change in the substance of the coloring layer, so that at least the same amount of electricity also passes through to the counter electrode. As a result, the elements constituting the transparent electron conductive film, such as NO203 and SNO2, are dissolved, and ions in the electrolytic solution are deposited on the surface of the counter electrode, causing damage to the counter electrode and rendering it unable to perform its function. In other words, the counter electrode deteriorates, resulting in a shortened lifespan.

Therefore, the following methods have been proposed to improve this problem.

(1) Use an electrode similar to the working electrode as a counter electrode.

That is, the counter electrode also holds an insoluble active material that can be charged and discharged.

(2) By reducing the coloring layer, that is, the layer of active material, arranged on the working electrode, and making the current flowing when a voltage is applied very small, the elution of the transparent electron-conducting film of the counter electrode and the precipitation of ions in the electrolyte are reduced. Slows down the rate of deterioration of the opposite electrode.

Problems to be Solved by the Invention In method 1 above, since both the counter electrode and the working electrode have an insoluble color-forming active material layer that can be charged and discharged, the life of the counter electrode, which had been a problem, can be improved. However, when the coloring/decoloring layer of the working electrode is colored, the counter electrode to which a reverse voltage is applied is in a bleached state, but if a voltage is applied in a direction that causes the working electrode to bleach, the counter electrode becomes colored. Due to this, complete decolorization is difficult with the general configuration in which both electrodes are stacked. For this reason, it is also possible to suppress the influence of coloring of the counter electrode by dispersing Ti02 powder in the electrolyte. However, although this method is suitable for display applications that reflect light from the working electrode side, the light
Since it is reflected and absorbed by iO3 and does not pass through the electrode, it cannot be used for a wider range of applications, such as filters.

The above method 2 has the disadvantage that deterioration of the counter electrode can be basically prevented by merely reducing the amount of the coloring layer, and the coloring power of the working electrode is also small.

The present invention solves these conventional problems,
The objective is to provide a transparent color-removable plate with no deterioration of the counter electrode and which can be used for filters and the like, and the counter electrode is provided with a colorless, transparent and insoluble active material layer.

Means to Solve the Problem In order to solve this problem, the present invention provides a Prussian blue thin layer on the surface of the transparent electron-conducting layer of the working and counter electrode, and anodically oxidizes this thin layer, which inherently has coloring and decoloring properties. By applying this process, it is made into a transparent active material.

Effect: According to this configuration, the transparent active material of the counter electrode reacts in response to the current passed for the coloring/decoloring reaction of the working electrode provided with the coloring layer, and the transparent active material of the counter electrode is not involved in the elution of the transparent electron conductive film of the counter electrode at all. ,
The lifespan of the opposite end can be extended.

At the same time, since it is a transparent active material, it can be used not only for display purposes that utilize reflected light from the working electrode, but also for coloring and decoloring properties in which the color of light passing from the front and back surfaces is affected only by the working electrode. .

EXAMPLES Examples of the present invention will be described below with reference to FIGS. 1 to 3.

FIGS. 1A and 1B show schematic diagrams of a transparent color-removable plate used for filter applications that can arbitrarily attenuate light. Note that it can also be used as a display by processing it into any shape. In the figure, 1 is a transparent working electrode, 2 is a working electrode that can be transparently attached/detached or transparently colored, and 3 and 3' are leads of each electrode, which make electrical contact with the reaction layer on the electrode surface. In order to maintain this, it is integrated with a resin that has electronic conductivity. This lead merely provides electrical contact with the outside, and may be a thin resin film printed with conductive powder. Reference numeral 4 is an electrolytic solution mainly composed of a 0.6M KC7 aqueous solution, and 5 is a backing made of, for example, epoxy resin for holding and integrating both electrodes and the electrolytic solution. Note that the distance between the electrodes was approximately 1 meter. Part of the visible light incident on the transparent working electrode 2 side is strongly absorbed by the colored layer of the transparent working electrode 2, producing a color, which passes through the transparent working counter electrode 1 and is observed from the opposite side.

Here, the details of the configuration of the working counter electrode and the working electrode are shown in Figure 1B.
This will be explained with reference to FIG. 2, which shows part C of FIG.

In the figure, 9 uses a glass plate with a transparent substrate, and 8 uses engineering n203.
evaporated to a thickness of 0.1μm, sheet resistance approximately 100Ω
/ 7 is a transparent electron conductive layer provided on the working electrode 2, and 7 is a transparent coloring/decoloring layer with a thickness of about 0.5μ mainly composed of WO2.
m layers were integrally deposited. Note that the transparent substrate of 0.9 may be a resin plate having heat resistance against the temperature during vapor deposition, or may be made of polyimide resin or the like. SnO3 may be used in place of step n203 in step 8, and Mo53 or Prussian blue may be used in the transparent coloring layer in step 7 without interfering with its original function.

6 is an important part of the action and counter electrode of the present invention, and the main component Fej+(
This is a transparent active material layer obtained by anodizing insoluble Prussian blue consisting of Fe''(CN)6]3, and is integrated with a backing 5 via an electrolyte 4.P/I/
Cyan blue is made by combining 0.02M of FeCl3-6H20 and 0.021V1 of KsFe(CN)e at 10
In an aqueous solution dissolved in 0 cc of water, electroplating was performed on the transparent electron conductive layer disposed on the transparent substrate at a current density of 5 μA/, -, I for 20 minutes to form a layer with an average thickness of 0.5 μm. Then, using the carbon electrode as a counter electrode in a KCl aqueous solution of ○, sM, 1. Anodic oxidation was performed at eV for 3 minutes to make it transparent and form a transparent active material layer.

The phenomenon that occurs on the absorbance due to anode polarization during this anode oxidation will be explained with reference to FIG. a1 to a4 are o, 3V, and 0.5V, respectively, with respect to the mercury chloride reference electrode.

o, eV, 1. It shows the absorption intensity versus wavelength when the anode was polarized for 3 minutes at a potential of oV. C indicates the absorption intensity with respect to the wavelength when a1 to a4 which have been anodically polarized are cathodically polarized (-0,3V), and a1 to a4
If the absorption intensity characteristics of are all cathodic polarized, they will be the same in this wavelength range. That is, a 1 , a 2
In C, it absorbs light on the longer wavelength side, so it exhibits a blue color, but in C, it is colorless because it allows most of the visible light to pass through. This is a normal transparent attachment/detachment nine-color reaction. However, when the anode polarization is set to o or eV, the absorption intensity characteristics begin to change drastically, and the absorption intensity of the entire visible light wavelength decreases, and rather the absorption intensity of short wavelengths becomes stronger. Therefore,
A slight yellowing phenomenon was observed. 1 more o
A4, which was polarized with V, became almost transparent. That is, even if anode polarization and cathode polarization are repeated, a
3. It has been found that a4 remains almost colorless and transparent, and is a colorless and transparent active material. Also, in the case of a3, if the anode polarization (oxidation) time is increased, a4
The absorption intensity characteristics approached that of . Therefore, when a transparent working counter electrode made by anodically oxidizing this Prussian blue layer to make it colorless is combined with a working electrode, the coloring and decoloring are controlled by the coloring reaction of the working electrode, and the WO2 changes between blue and colorless. A transparent removable color plate was constructed.

In addition, during anode polarization, the Prussian blue layer peels off in a KCl aqueous solution of 1.0 M or more, resulting in a low concentration (approximately
3M KCl or less), the time for colorlessness will be longer, so
．． 3-1.0M KCl is a practically preferred concentration.

Effects of the Invention As described above, according to the present invention, a transparent coloring/decoloring plate that is combined with a working counter electrode provided with a transparent active material layer and a working electrode provided with a transparent coloring/decoloring layer can solve the problem of the conventional transparent electron conductive layer. Since no deterioration is observed at all, and the color of the light passing through this combination plate is controlled only by the reaction of the working electrode, it has the advantage that it can be used not only for electrochromic displays but also for a wide range of applications such as light attenuation filters. can get.

[Brief explanation of drawings]

Figures 1A and B are a schematic diagram and a cross-sectional view of a transparent coloring/decoloring plate according to an embodiment of the present invention, Figure 2 is an enlarged cross-sectional view showing part C in Figure 1B, and Figure 3 shows various Prussian blue layers. FIG. 3 is a diagram showing changes in absorption intensity characteristics when the anode is polarized at a potential of . 1... Transparent counter electrode, 2... Working electrode, 4
... Electrolyte solution, 6 ... Transparent active material layer, 7.
. . . Transparent coloring layer, 8 . . . Transparent electron conductive layer, 9 . . . Transparent substrate. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Me 1 So F Figure 3 400 500 67) 0 70θ 8θθ S1 meeting;
(α9)

Claims (2)

[Claims] (1) A transparent coloring/decoloring plate in which a working electrode that produces a transparent color change due to an electrochemical reaction and a working counter electrode facing each other via an electrolyte are integrated in a plate shape, and the working counter electrode is formed on a transparent substrate. It has a transparent electron conductive layer on top, and further has Fe on it.
It has a structure with a Prussian blue layer mainly composed of ^3^+_4 [Fe^II (CN)_6]_3, and the Prussian blue layer is a transparent coloring and decoloring layer made of an anodized transparent and nearly colorless active material. Board. (2) The transparent coloring/decoloring plate according to claim 1, wherein the anodic oxidation is performed by applying a potential of 0.6 V or more to a mercury chloride reference electrode in a KCl aqueous solution. (2) The transparent coloring/decoloring plate according to claim 1, wherein the electrolytic solution consists of a 0.3 to 1.0 mol KCl aqueous solution, and the Prussian blue layer is anodized in this electrolytic solution.