JPH07111524B2 - Electrochromic device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel electrochromic device.

(Prior Art) In recent years, an electrochromic element has been attracting attention as a new display device replacing a liquid crystal display device. Electrochromic devices have less visual dependence than liquid crystals, display is clear, and a memory effect allows display to continue without power consumption.

Electrochromic devices utilize electrochromism in which light absorption characteristics change according to voltage application or current, and materials having such properties can be roughly classified into inorganic materials and organic materials. As inorganic materials, oxides of transfer metals such as tungsten oxide and complexes such as Prussian blue have been mainly studied. In addition to phthalocyanine and viologen complex, conductive polymer materials have been studied as organic materials.

The discoloration mechanism of inorganic materials is generally due to the change in spectral structure due to charge transfer of the transition metal. Therefore, the response speed of color change is faster than that of organic materials, but protons are often involved in the charge transfer reaction, and the deterioration of the electrode is likely to occur. In addition, the color tone is poorer than that of organic materials. Even with organic materials, phthalocyanine and the like are vapor-deposited on the substrate, but there remains a problem with the adhesion to the electrodes. On the other hand, the conductive polymer has the advantage that the film can be easily formed and the area can be increased, and various proposals have been made. For example, Japanese Patent Application Laid-Open No. 61-238028 discloses polyaniline. It has been proposed to use films such as Polypyrrole, Polythiophene, etc.

However, the above resin did not cause a sharp color change, and was insufficient for use as an electrochromic device.

(Problems to be Solved by the Invention) An object of the present invention is to provide an electrochromic device that exhibits a sharp color change in view of the above-mentioned drawbacks.

(Means for Solving the Problem) The electrochromic device of the present invention has a structure in which an organic coloring layer and an electrolyte layer are arranged between a transparent electrode and a counter electrode, and the organic coloring layer is represented by the general formula (I). It is an acetylene polymer mainly composed of the constitutional unit shown in FIG.

In the formula, R ¹ , R ² and R ³ are hydrogen or a trialkylsilyl group (the alkyl group has 6 or less carbon atoms), and may be the same or different, for example, poly (o -Trimethylsilylphenyl) acetylene, polyphenylacetylene, and the like.

Any method may be adopted as the method for producing the above-mentioned acetylene-based polymer, and it is described in, for example, JP-A-63-92619.

The transparent electrode used in the present invention may be any transparent electrode, for example, a semiconductor thin film of indium oxide / tin oxide, tin oxide, titanium oxide, etc., a metal thin film of gold, silver, etc. , Those laminated on a plastic film and the like.

The counter electrode used in the present invention can be any conventionally known electrode, other than the transparent electrode, a metal plate, an amorphous tungsten oxide-iron complex, a transition metal oxide-carbon sintered body,
Examples include manganese oxide and the like.

The electrolyte layer used in the present invention may be a solid phase,
It may be in a liquid phase, and examples thereof include the following.

(1) An inorganic dielectric thin film of tantalum oxide, niobium oxide, titanium oxide or the like.

(2) By dissolving the electrolyte such as lithium perchlorate, tetraethylammonium borofluoride, lithium iodide and the like and the resin component such as polyvinyl alcohol, polyvinyl butyral and polyethylene oxide in a solvent capable of dissolving them, and then removing the solvent. The resulting polyelectrolyte.

(3) A liquid phase electrolyte obtained by dissolving the above electrolyte in an organic solvent such as acetonitrile or nitromethane.

In the electrochromic device of the present invention, the organic coloring layer and the electrolyte layer are arranged between the transparent electrode and the counter electrode, that is, the coloring layer is in close contact with either the transparent electrode or the counter electrode, and the electrolyte layer is the other. At the interface between the coloring layer and the electrolyte layer, ions have a structure in which ions freely move in and out due to charge transfer at the electrode interface. A color change occurs in the organic coloring layer due to the ingress and egress of the ions.

(Example) Next, the Example of this invention is described.

Example A solution prepared by dissolving 1 g of poly (o-trimethylsilylphenyl) acetylene (weight average molecular weight of 1,000,000) in 60 ml of toluene was spin-coated on a vapor deposition layer of a transparent electrode on which a glass plate was vapor deposited with indium oxide-tin oxide. It dried and the organic coloring layer was laminated.

A solution prepared by dissolving 1 g of lithium perchlorate and 10 g of cyanoethyl poval in 40 ml of methyl ethyl ketone was applied and dried on the vapor-deposited layer of the counter electrode having indium oxide-tin oxide deposited on one surface of the polyethylene terephthalate film, and the electrolyte layer was laminated.

The transparent electrode and the counter electrode thus obtained were superposed so that the organic coloring layer and the electrolyte layer were in contact with each other, and the transparent electrode was the anode, the counter electrode was the cathode, and a potential of 1.8 V was applied between both electrodes. The color changed from purple to colorless, and when a potential of -1.2 V was applied next, the color changed from colorless to magenta. Both of these color changes required 0.05 seconds.

Also, the potential was repeatedly changed between 1.8V and -1.2V,
The color change did not change even after repeated times.

(Advantages of the Invention) Since the electrochromic device of the present invention has the above-described configuration, it exhibits a clear color change due to the difference in applied voltage and is excellent in durability.

Claims (1)

[Claims] 1. In an electrochromic device in which an organic coloring layer and an electrolyte layer are arranged between a transparent electrode and a counter electrode, the organic coloring layer mainly comprises a structural unit represented by the general formula (1). An electrochromic device characterized by being an acetylene polymer. "In the formula, R ¹ , R ² , and R ³ are hydrogen or a trialkylsilyl group (the alkyl group has 6 or less carbon atoms), and may be the same or different."