CHARACTERISTICS OF ELECTROCHROMIC MATERIALS AU-WO3 AND PT-WO3+

The electrochromic cermet Au-WO3 is composed of grains of Au, approximately 20-120å in diameter, embedded in a matrix of amorphous WO3. As prepared, the cermet is blue and when electrochemically colored it is red or pink. The matrix must be amorphous in order for the red color to develop. In polycrystalline Au-WO3 films, the colored state is dark blue. We find that the properties of the amorphous WO3 matrix in the presence of Au are different from pure amorphous WO3. In particular, the presence of the Au grains suppresses the high electrical conductivity characteristic of colored WO3. Pt-WO3 cermets are compared and contrasted with Au-WO3. We discuss the optical and electrical properties of the Au-W03 cermets and their possible use in display devices. © 1979 AIME.