The degradation mechanism of gradual decrease of the contrast between colored and bleached states of Lix'. WO3 films with switching cycles was investigated. We made electro-chemical and quantitative chemical analyses to clarify this phenomenon. It was found that the decrease in contrast was mostly attributed to the parallel cathodic shift of emf(x), passibly caused by ion exchange reaction expressed by: WOH + Li+ WOLi + H. Fully ion-exchanged WO3 films showed no appreciable change in spite of the presence of a large amount of Li in them. These films were capable of accepting as much Li as the fresh films did on coloration and reached to the same optical densities. It is concluded that there are two kinds of active sites available for accepting lithium ions in the WO3 structure, one for ion exchange and the other for coloration.

Date Published: 2 November 1984
PDF: 9 pages
Proc. SPIE 0502, Optical Materials Technology for Energy Efficiency and Solar Energy Conversion III, (2 November 1984); doi: 10.1117/12.944786

Published in SPIE Proceedings Vol. 0502:
Optical Materials Technology for Energy Efficiency and Solar Energy Conversion III
Carl M. Lampert, Editor(s)