JPH0730314B2 - Electrochromic display material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an EC film to be deposited on the surface of a display electrode in an electrochromic display device, which comprises a basic dye or a cationic dye and a polymer having an anionic functional group. The present invention relates to an EC display material characterized by being used as a redox polymer.

[Technical background of the invention]

Amorphous tungsten oxide, viologen derivatives, viologen polymers, metal phthalocyanines, polythiophenes, etc. can be used as conventional representative EC materials.
An EC display device has been developed in which this is fixed as a thin film on the surface of a transparent electrode. However, the above-mentioned EC material alone causes only color change of colorless / colored or 2 to 4 colors, and it is difficult to make the EC display element multi-colored unless several EC materials are combined.

Many basic dyes and cationic dyes have a positive charge in the molecule and can form a polyion complex by electrostatic interaction with a polyanion polymer. As a result, a polyanion polymer having these dyes fixed thereon can be deposited on the transparent electrode and used as an EC display device. Basic dyes and cationic dyes are generally inferior in light resistance to acid dyes and the like, but it is known that fixing them in a polymer such as a polyanion polymer markedly increases light resistance and weather resistance (Japanese Patent Laid-Open Publication No. 2005-242242). 60-
18559, Sho 60-11542). Therefore, an EC display device produced by coating the above-mentioned polymer dye on a transparent electrode is expected to have excellent stability such as light resistance and weather resistance.

The present inventors have fixed various basic dyes and cationic dyes on the polyanion polymer film coated on the transparent electrode surface,
As a result of studying the EC characteristics of this membrane-coated electrode, it was found that this electrode exhibits excellent EC characteristics in an appropriate supporting electrolyte solution, and the present invention was completed.

[Object of the Invention] An object of the present invention is to provide a novel redox polymer membrane using a basic dye or a cationic dye as an EC substance, and comprising this and a polyanion polymer as a support for the EC substance.

[Outline of Invention]

The present invention uses a basic dye or a cationic dye having a wide variety of colors and high chromaticity as an EC substance to create an EC display device capable of developing various colors, and these on a transparent electrode surface. An EC display material using a polyanionic polymer forming a polyion complex with a dye for immobilization as a dye support.

In the present invention, an oxazine dye, a thiazine dye, an azine dye, a methine dye, an azo dye or a triarylmethane dye, which is a basic dye or a cationic dye, can be used as an EC substance constituting the EC film. Typical examples of these dyes are shown below.

(1) Oxazine dye (2) Thiazine dye (3) Azine dye (4) Methine dye (5) Azo dye (6) Triarylmethane dye Each of these dyes has a cationic functional group in the molecule and forms a polyion complex with the anionic functional group in the polyanionic polymer film. Therefore, the dye can be concentrated and fixed in the film by immersing the transparent electrode coated with the polyanion polymer film in the aqueous solution of these dyes.

The polyanionic polymer used in the present invention includes poly (sodium styrenesulfonate) (hereinafter abbreviated as PSS), poly (sodium styrenesulfonate) -poly (n-butylmethacrylate) copolymer (PSS-PB
M), poly (styrene) -poly (sodium styrenesulfonate) copolymer (PS-PSS) or poly (sodium perfluorosulfonate) (NAFION).
When the transparent electrode thus prepared is immersed in an appropriate supporting electrolyte solution and a voltage is applied to the electrode, a color change occurs due to the oxidation or reduction of these dyes, so these electrodes can be used for EC display devices. .

〔The invention's effect〕

According to the present invention, by using the above dye, blue,
There are a wide variety of colors such as red, green, and yellow, and it is possible to prepare an EC film that develops a mixed color of these colors. Furthermore, by fixing two or more kinds of dyes in the film, it is possible to prepare an EC display element that emits at least three kinds of colors including the white background by controlling the applied voltage. Further, by fixing a basic dye or a cationic dye, which is inferior in light resistance to an acid dye, to a polyanion polymer film, these dyes, light resistance and weather resistance can be remarkably enhanced, and an EC film having excellent durability can be prepared. .

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples.
The invention is not limited to these examples only.

Example 1 A 1 wt% solution of a polymer represented by the formula 1 (a solution having a composition of ethanol: dimethyl sulfoxide = 1: 1 in volume ratio was used) was applied to a transparent electrode having an area of 1 cm ² at 2 × 10 ^−3. ml was placed and only the solvent was air dried. A solution containing 1 mM galocyanine (volume ratio of water: dimethyl sulfoxide = 4:
1) and then the electrode was taken out, washed with water and dried.

In this way, a polyanion polymer film-coated electrode in which galocyanine was concentrated and fixed was prepared. Using this as the working electrode, a platinum winding as the counter electrode and a saturated sodium chloride calomel electrode (hereinafter abbreviated as SSCE) as the reference electrode, an ordinary 3-electrode H-type cell was used. I checked. The electrolyte solution used was an aqueous solution containing 0.1 M perchloric acid and 0.2 M sodium perchlorate at pH 1.0. Prior to electrolysis, nitrogen was sufficiently aerated in the electrolyte solution to remove oxygen in the solution. The polymer film-coated electrode prepared as described above was immersed in this solution, and -0.2 V to +0.
The potential range of 5 V (vs SSCE) was repeatedly subjected to potential scanning. The results are shown in FIG. The scanning speed of the electric potential is 200 mV / s. In the current-potential curve based on the redox reaction of galocyanine, the anodic and cathodic peak potentials are at +0.24 V and +0.16 V (vs SSCE), respectively, and it is possible that galocyanine reacts reversibly within this potential range. Recognize. It was confirmed that galocyanine changes from purple to colorless by the reduction reaction, and changes from colorless to purple by the oxidation reaction. The peak current of the current-potential curve did not decrease even after repeated potential scanning, indicating that galocyanine was stably fixed in the polymer film.

Examples 2 to 6 In addition to the galocyanine (Ga) used in Example 1, here, methylene green (MG) as a thiazine dye, safranine T (Sa-T) as an azine dye, and Basi as a methine dye.
c Red 14 (BR-14), Basic Blue as an azomethine dye
Brilliant Green (BG) was used as the 41 (BB-41) and triarylmethane dye, respectively. For polyanionic polymer, PSS and PSS-PB represented by formulas 2 to 4
M and PS-PSS were used.

According to the method described in Example 1, a polymer film-coated transparent electrode having a dye immobilized thereon was prepared. 2 x 10 ^-3 ml of 1 wt% polyanion polymer solution (water was used for PSS, and toluene was used for PSS-PBM and PS-PSS respectively) was placed on a transparent electrode with an area of 1 cm ² , and only the solvent was air-dried. did. This electrode was immersed in a solution containing 1 mM of each dye (volume ratio of water: dimethylsulfoxide = 4: 1) for 5 minutes, and then the electrode was taken out, washed with water and dried. The experimental conditions are shown in Table 1 together with Example 1.

Table 1 Examples Dyes Polyanionic polymer 1 Ga NAFION 2 MG PSS 3 Sa-T PS-PBM 4 BR14 PS-PSS 5 BB41 PS-PBM 6 BG NAFION The polymer membrane-coated electrode thus prepared was used as a supporting salt in an amount of 0.1M. It was immersed in an acidic aqueous solution (pH 1.0) containing perchloric acid and 0.2 M sodium perchlorate, and the potential was scanned to obtain a current-potential curve based on the redox reaction of each dye.
However, in Example 3, a mixed solution containing 0.1 M hydrochloric acid (volume ratio of water: ethanol = 4: 1) was used as the electrolyte solution. This is shown in FIGS. It was confirmed that these redox waves did not change even after repeated potential scanning, and that the color change of the EC film occurred with good reproducibility. Table 2 shows the change in color of each dye.

[Brief description of drawings]

1 to 6 show current-potential curves obtained by immersing a transparent electrode coated with a polymer film on which a dye is fixed in an electrolyte solution and then scanning the potential.

Claims (3)

[Claims] 1. An EC display material characterized in that a coloring substance fixed in an EC film deposited on a transparent electrode of an electrochromic (hereinafter abbreviated as EC) display element is a basic dye or a cationic dye. . 2. The EC display material according to claim 1, wherein the EC film is a polymer film having an anionic functional group which is a support for the EC substance and a basic dye or a cationic dye as the EC substance. 3. The EC display material according to claim 2, wherein the basic dye or the cationic dye is an oxazine dye, a thiazine dye, an azine dye, a methine dye, an azo dye or a triarylmethane dye.