JP2501133B2 - Electrochromic device - Google Patents

Description

Detailed Description of the Invention

[0001]

This invention relates to electrochromic devices.

[0002]

2. Description of the Related Art In recent years, electrochromic devices have been attracting attention as display device materials replacing liquid crystal devices. This has the advantage that the electrochromic element has less visual dependency than the liquid crystal element, the display is clear, and the memory effect allows the display to continue without power consumption. Because.

The electrochromic element utilizes electrochromism in which the light absorption characteristics of the material change and discolor depending on the value of the applied voltage and current, and an inorganic material is a material having such properties. Can be roughly divided into those consisting of and organic materials.
As inorganic materials, oxides of transition metals such as tungsten oxide and complexes such as Prussian blue have been mainly studied. Further, as organic materials, phthalocyanine, viologen complex, conductive polymer materials and the like have been studied.

Discoloration of an electrochromic device made of an inorganic material is generally caused by a change in light absorption characteristics due to charge transfer of a transition metal. Therefore, the response speed of the color change is faster than that of the organic material, but since the protons are often involved in the charge transfer reaction, the electrode is likely to deteriorate. In addition, there is a defect that the color tone is poor as compared with those made of organic materials.

On the other hand, in the case of an element made of an organic material, for example, when phthalocyanine is used, it is possible to form a color forming layer by vapor deposition on a substrate, but there is a problem in adhesion to the electrode, and Cause deterioration and uneven color. On the other hand, when a conductive polymer is used, there is an advantage that a film having good adhesion can be easily formed and the area can be increased.

Various proposals have been made so far regarding conductive polymers, for example, JP-A-61-2380.
In Japanese Patent No. 28, it is proposed to use a film of polyaniline, polypyrrole, polythioene or the like. However, the method using the above-mentioned film has a drawback that uneven color is caused because the film thickness is not uniform.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrochromic device having no color unevenness in view of the above drawbacks.

[0008]

The transparent electrode used in the present invention is not particularly limited as long as it is transparent. For example, indium oxide doped with tin (hereinafter referred to as ITO). Examples thereof include semiconductor thin films of tin oxide, indium oxide, titanium oxide, etc., metal thin films of gold, silver, etc., and those in which these thin films are laminated on a transparent substrate.

[0009] Examples of materials used for the transparent substrate include glass and acrylics, vinyls, polyolefins, polyesters, polyamides, and polycarbonate.
Polymers such as G-type are listed. As the counter electrode used in the present invention, any conventionally known electrode can be used, and in addition to the transparent electrode, for example, a metal plate, amorphous tungsten oxide-
An iron complex, a transition metal oxide-carbon sintered body, manganese oxide, etc. are preferably used.

In the electrochromic device of the present invention, an organic coloring layer and an electrolyte layer are provided between the transparent electrode and the counter electrode. The organic color-developing layer is made of an acetylene-based polymer mainly composed of a structural unit represented by the following general formula.

[0011]

Embedded image In the formula, R ¹ , R ² , and R ³ are hydrogen, an alkyl group having 10 or less carbon atoms, or an alkoxy group having 10 or less carbon atoms, and at least one of R ¹ , R ² , and R ³ is an alkoxy group. is there. Note that R ¹ , R ² and R ³ may be the same or different groups.

Examples of the acetylene-based polymer include poly (o-methoxyphenylacetylene), poly (p-methoxyphenylacetylene), poly (o-ethoxyphenylacetylene), poly (p-ethoxyphenylacetylene), and poly (p-ethoxyphenylacetylene). Examples include [(4-methoxy-2,5-dimethylphenyl) acetylene] and the like. Any method may be adopted as the method for producing the acetylene-based polymer, for example, Journal of Polymer Science: Part A: Poly.
mer Chemistry, Vol.27, 4267-4279 (1989).

The electrolyte layer used in the present invention may be a solid layer or a liquid layer, and examples thereof include the following. (1) Inorganic dielectric thin films such as tantalum oxide, niobium oxide, and titanium oxide. (2) Lithium perchlorate, tetraethylammonium borofluoride, electrolytes such as lithium iodide and polyvinyl alcohol, polyvinyl butyral, resin components such as polyethylene oxide, after both are dissolved in a soluble solvent, A polymer electrolyte obtained by removing a solvent.
(3) A liquid layer electrolyte in which the above polymer electrolyte is dissolved in an organic solvent such as acetonitrile or nitromethane.

[0014]

Embodiments of the present invention will be described below. Example 1 A solution prepared by dissolving 1 g of poly (o-methoxyphenylacetylene) in 20 ml of toluene was spin-coated on an ITO layer of a transparent electrode made of a glass plate on which ITO was deposited,
It dried and the organic coloring layer was laminated.

Next, 1 g of lithium perchlorate and 3 g of polyethylene oxide were dissolved in a mixed solvent of acetonitrile / water = 1/1 (volume ratio) to form a polyretylene phthalate film on which ITO was deposited. Counter electrode I
An electrolyte layer was laminated by coating on the TO layer and drying. The transparent electrode and the counter electrode were superposed so that the organic coloring layer and the electrolyte layer were in contact with each other, and the transparent electrode was used as an anode, the counter electrode was used as a cathode, and a voltage of 3 V was applied between both electrodes. The color changed to light gray, and when a voltage of -3 V was applied, the color changed from light gray to brown. No color unevenness was observed in the changed color.

When the potential was repeatedly changed between 3V and -3V, reversible color change from brown to light gray occurred.

[0017]

The electrochromic device of the present invention is
Because of the above-described configuration, the sharpness of color change due to the difference in applied voltage and the uniformity of color are excellent. Further, since the material used for the color forming layer is soluble in an organic solvent, a large area can be easily obtained by coating.

Claims (1)

(57) [Claims] 1. An electrochromic device in which an organic coloring layer and an electrolyte layer are provided between a transparent electrode and a counter electrode, wherein the coloring layer is mainly composed of a structural unit represented by the following general formula. Is an electrochromic device. Embedded image (In the formula, R ¹ , R ² , and R ³ are hydrogen, an alkyl group having 10 or less carbon atoms, or an alkoxy group having 10 or less carbon atoms, and at least one of R ¹ , R ² , and R ³ is an alkoxy group. Is)