PURPOSE: To obtain a stable ECD having good driving performance and visibility by using display electrodes provided with iron hexacyano-ferrate films on a substrate having a conductive surface and using univalent cations as one of mobile ions of an electrolyte.
CONSTITUTION: Iron hexaamino-ferrate as an electrochemical coloring material is electrolytically deposited on transparent electrodes provided with an SiO2 film on a glass substrate to provide a working electrode of an ECD. The EC film is a blue pigment known as prussian blue, and its chemical structure is expressed by the formulasI, II. Said film is a mixed valency complex wherein tervalent iron and bivalent iron exist simultaneously in the same crystal. If the tervalent iron is fully reduced to the bivalent iron, the blue color disappears without any change in crystal structure and becomes colorless. The chloride contg. univalent cations expressed by the formula II is used as an electrolyte of the ECD. The ion radii of the cations resemble and the cations go into and out from the EC film complex, thus providing the ECD having long-term stable driving performance.
SHIBAYAMA KIMIO
SOTOJIMA SHINOBU
ATAKA TATSUAKI
IWASA KOUJI
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