Solid state electrochromic display

Abstract

This paper is concerned with reversible electrochemical cells based on the solid electrodes, alkali metal tungsten bronze/ß-alumina. The electrochromic effect (colourless/blue) is associated with insertion of alkali metal atoms into tungstic trioxide. The fabrication of ECD cells involves the deposition of WO3, ITO and SiO2 in thin-film form on the ß-alumina fast ion conductor. The solid electrolyte is thus the substrate for deposition as well as the medium which optically isolates the viewing electrode from the counter electrode. The atomistic model of atom insertion into WO3 is described and the importance of the role of the free electron gas, in electrode potential, atom diffusion and optical absorption, is pointed out. The prospects of ECD based on the oxide bronzes are considered to be excellent. © 1981.