JPS6132037A - Electrochromic device - Google Patents

Abstract

PURPOSE:To obtain an electrochromic device having a high response speed and not causing foaming and reduction in the response speed due to light, ultraviolet rays or heat by adding a lactone solvent and a substance for an iodine ion source to an electrolyte soln. or by further adding a substance for a cation source. CONSTITUTION:A metallic iodide such as LiI or NaI having a high response speed and superior durability as a redox agent and a lactone solvent for the redox agent such as beta-, gamma- or delta-lactone having satisfactory properties with respect to dielectric constant, b.p., stability and durability are added to an electrolyte soln. 6 in a electrochromic (EC) device having a transparent front substrate 1. When NH4I or an ammono-iodide such as (C2H5)4NI is used in place of the metallic iodide, a substance for implanting H<+>, Li<+> or other cation which makes a layer 5 of an EC substance develop color is added to the electrolyte soln 6. The generation of gaseous CO2 and H2 from the soln. 6 is prevented, and a thermally stable EC device not causing coloring due to light and having superior durability and weather resistance is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an electrochromic/erasable device, and particularly to an electrochromic/erasable device using a so-called electrochromic (hereinafter abbreviated as EC) material.

[Prior Art] In recent years, electrochromic/erasable devices using EC substances have begun to be used as anti-glare mirrors, dimming windows, various display elements, and the like.

Such an electrochromic coloring/decoloring device usually has a distance of 1 liter between the electrode substrate.
03, M o 03, etc., and an electrolyte solution containing ions capable of coloring the EC material.

As the electrolyte solution, various compositions have been studied as systems containing Hl or L1+ with good conductivity, but typically, for example, as described in JP-A-55-138720, , Li4 such as LiC104
Ion sources in which an ion source material is dissolved in a solvent such as propylene carbonate (hereinafter abbreviated as PC) are known, while those in which Li3N or LiI are used as Li conductive solid electrolytes are also known.

[Problems to be solved by the invention] The present inventors have proposed an invention that has already been applied for (Japanese Unexamined Patent Publication No. 58-307
In 29), it was shown that by adding a redox agent to the electrolyte, a light control body using a transparent electrode as a counter electrode could be obtained. It was found that the source material exhibits properties superior to other redox agents in terms of responsiveness and durability. However, when Lil, for example, is used in solution form as such an iodine ion source material, CO2 gas is generated at high temperatures, Li2003 is precipitated, and when exposed to light, PC is used as a solvent. There was also a drawback that CO2 gas was generated even when In addition, alcoholic solvents such as butyl alcohol (hereinafter referred to as BuOH) may also be used.
When the light irradiation is terminated, the flat band potential of the surface of the EC material, such as 1l103, in contact with the electrolyte solution shifts in the positive direction, making it easier to be colored by the light, and H2 The disadvantage was that gas was generated.

The present invention was made in order to eliminate the above-mentioned drawbacks of conventional electro-coloring and decoloring devices, and it is an electrolytic solution that uses an electrolyte solution that is thermally stable and does not cause phenomena such as foaming and coloring due to light. The purpose of the present invention is to provide a color erasing device.

Means for Solving Problem E] That is, the electrolytic coloring/erasing device of the present invention uses an iodine ion source material that has excellent reaction speed and durability as a redox agent in an electrolyte solution, and uses an iodine ion source material as a solvent for dissolving the redox agent. It is recommended to use a lactone-based solvent that has excellent properties as a solvent such as dielectric constant, dropping point, stability, and durability, and a cation source substance when the iodine ion source substance does not function as a cation source. Features.

The present invention will be explained in detail below.

The electrode substrate is made of 5n02.11203 or indium tin oxide (
A conductive transparent film such as ITO) formed by a known method such as coating, vapor deposition, or sputtering to form an electrode is used. Note that in applications such as light control mirrors that do not require light to pass through the electrochromic/erasable device, one of the substrates does not need to be transparent and may be made of ceramic or metal such as AI. Also, TiN and ZrN can be used as electrodes.

A reflective electrode such as HfN may also be used. Furthermore, when used as a light control mirror, both of the electrode substrates may be transparent, and a mirror surface may be formed on the back surface of one of the electrode substrates.

EC substances are WO3, Mob, , Tio2+ Ir
Known substances such as 2p3 can be used, but l1103-based substances are preferable.

An iodine ion source substance is used as a redox agent for the electrolyte solution, and examples of the iodine ion source substance include Lil, N
Metal iodides such as a1 and NH4.

(C2Hh) a Ammonium iodide such as N1 is used. When ammonium-based iodide or the like is used, it is necessary to add cations such as H+ or Li", which cause the EC material layer to develop color, for ion implantation into the EC material layer.

Such redox agents require a counter electrode to be a transparent or reflective electrode, and are used in electroluminescent devices such as dimming mirrors and dimming windows where opaque counter electrodes cannot be formed like in ordinary display elements. Particularly effective results are obtained when used in decolorizing devices. Further, the electrical coloring/decolorizing device of the present invention has a cycle life of 106 times or more for coloring/decolorizing when used as a small display, and can be put to practical use as a display by devising a driving system.

As a solvent for dissolving the redox agent, β-lactone,
Lactone-based substances such as γ-lactone and δ-lactone are used. Add 0 of the above iodine ion source substances to this solvent.
．． An electrolyte solution is prepared by adding 0.001 M/liter to saturation. Among these lactone-based substances, they have a high boiling point and can be used at high temperatures, a high dielectric constant that allows them to transport a large amount of solutes and good conductivity, and a low freezing point that allows them to be used at low temperatures. γ-Butyrolactone (hereinafter abbreviated as γ-BL) is particularly desirable because it has all the desirable properties as a solvent, such as being able to absorb the oxidation agents and being non-toxic.

In addition, a thickener such as polyvinyl butyral (PVB), urethane, or acrylic polymer may be added to the electrolyte solution to gel the electrolyte solution.

[Example] Hereinafter, an electric coloring/decoloring device according to an example of the present invention will be described with reference to the cross-sectional view of FIG.

I was deposited on the glass back substrate 3 of 10C1ll square by vapor deposition.
A transparent electrode 4 is formed by coating a TO film to a thickness of 1,500 mm. Furthermore, a film with a thickness of 50 mm is formed on the transparent electrode 4 of the back substrate 3J:
An EC material layer 5 is formed by depositing a 11i03 film.

In addition, ITOII was placed on a 10 cm square glass front substrate 1.
The transparent electrode 2 is formed by vapor depositing a film having a thickness of 1500 Å.

A cell is formed by facing the front substrate 1 and the back substrate 3 so that the distance between the ITO film and the Wσ3 film is 200 m, and in the cell, γ-BL is applied at a rate of 0.5 M/m. An electrolyte solution 6 in which Lil was dissolved was injected and sealed with a sealing material 7 to produce a light control element 8.

This light control element 8 has a response speed of 10 seconds from 80% to 20% coloring in OoC, and has excellent characteristics in the cycle test shown in Figure 2 and the heat resistance test shown in Figure 4. showed that.

That is, Fig. 2 is a graph showing data after a cycle test in which a voltage of ±1 V is applied to the electrodes of the dimming element for 1 minute each to repeat coloring and decoloring, and the vertical axis is the data after applying the voltage for 171 minutes. The amount of electricity injected, the horizontal axis shows the number of cycles, the data marked with 0 is the data of the above-mentioned example, and the data marked with Δ is obtained by using PC as a solvent and an electrolyte solution containing 0.5 M/l LiT dissolved in PC. The data of the light control element used, the data marked with 0, uses BuOH as the solvent and 0.5 Mi of Li in BuOH.
This is data of a light control element using an electrolyte solution in which L is dissolved. The measurement was performed at room temperature, and the unit of the amount of electricity injected was [mC
/cnl].

As is clear from the figure, Lil, as a redox agent,
The light control element of this example using γ-〇, L as a solvent is as follows:
Compared to those using other solvents, it exhibited stable and fast response characteristics and was able to survive a 105 cycle test.

FIG. 3 is a graph showing data from a test in which a light control element is left outdoors to examine its resistance to use in a natural environment such as ultraviolet rays and rain, and is referred to as an outdoor exposure cycle test. The specimen, test method, etc. are the same as the cycle test shown in FIG.

In this test, the light control element using B u OH as a solvent foamed and stopped discoloring after 103 cycles. Further, in the light control element using Pc as a solvent, the amount of injected electricity decreased extremely from the 102 to 103 cycles, and foaming occurred at the 105 cycles. Compared to these, the light control element of this example using γ-BL as a solvent shows a slight decrease in the amount of injected electricity after 105 cycles, and exhibits sufficient toughness for practical use without foaming. Ta.

Figure 4 shows the weather resistance test data using Weather-O-Meter (hereinafter abbreviated as WOM), and the horizontal axis is WOM.
The vertical axis shows the amount of electricity injected when applying a voltage of ±IV for 1 minute.

In this test, both of the light control elements using BuOH and PC as solvents foamed and did not fade after 500 hours of testing. In comparison, the light control element of this example using γ-BL withstood the test for 2,000 hours without foaming and showed sufficient practicality.

Figure 5 is a graph showing heat resistance test data, where the horizontal axis shows the number of days left in an environment of 60°C, and the vertical axis shows soil IV.
, shows the amount of electricity injected when voltage is applied for 1 minute.

In this test, the light control element using Pc as a solvent was
After being left for 0 days, white powder precipitated and became unusable.

In this test as well, the light control element of this example using γ-BL as a solvent exhibited high-speed response characteristics and was sufficiently practical to withstand heating for 30 days.

[Effects of the Invention] As explained above, the electrolyte coloring and decoloring device of the present invention uses an electrolyte solution in which an iodine ion source substance is dissolved as a redox agent in a lactone solvent, so the response speed is fast and light It does not foam or reduce response speed even under adverse environments such as irradiation with ultraviolet rays, high temperatures, etc. It also withstands 106 cycle tests and has sufficient weather resistance and durability.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIGS. 2 to 5 are graphs showing various test results of the embodiment of FIG. 1. 1.3---One substrate 2.4---One transparent electrode 5
--------E C material layer 6-------1 Electrolyte solution 7--Sealing material 8---------1 Dimming element spear 1 Figure □Old school Figure 2 -+ Number Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. In an electrochromic coloring/decolorizing device comprising an electrochromic material layer and an electrolyte solution interposed between opposing electrode substrates, the electrolyte solution contains at least a lactone solvent, an iodine ion source material, and the iodine. An electrochromic/erasing device characterized in that it contains a cation source substance when the ion source substance does not function as a cation source. 2. The electrochromic/erasable device according to claim 1, wherein the lactone solvent is γ-butyrolactone. 3. The electrochromic/decolorizing device according to claim 1 or 2, wherein the iodine ion source material is a metal iodide. 4. The electrochromic/erasable device according to claim 3, wherein the metal iodide is lithium iodide. 5. The electrochromic/decolorizing device according to claim 1 or 2, wherein the iodine ion source material is an ammonium-based iodide.