ELECTROCHROMIC CHARACTERISTICS FOR ALL SOLID-STATE ECD COMPOSED OF POLYMER ELECTROLYTES

All solid state WO3-prussian blue (PB) based ECD is constructed with polymer electrolyte, and their electrochromic mechanism is investigated. From the analyses of cyclic voltammogram for PB or WO3 electrode measured in two or three electrodes system, electrochromic behavior of this ECD is indicated to be controlled by the electrochemical reaction for PB electrode. When alkali metal thiocyanates (MSCN) are used as additive salts for polymer electrolyte, resulting solid state ECD shown good electrochromic characteristics. Weak interaction between cation and surrounding polar environment is revealed to be effective to improve EC characteristics, because the cation should be fully desolvated from ether oxygens of polymer in order to be injected into PB lattice for such a ECD. Their coloring and bleaching mechanisms are discussed with the electrochemical behaviors in this ECD. © 1990.