Self-bleaching mechanism of electrochromic WO{sub 3} films

Book · Fri Dec 31 04:00:00 EST 1993

OSTI ID:201305

Zhang, J G; Benson, D K; Tracy, C E; Webb, J; Deb, S K ^[1]

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1. National Renewable Energy Lab., Golden, CO (United States)

The authors report the first investigation of the self-bleaching behavior of electrochemically colored WO{sub 3} films. These films exhibit accelerated self-bleaching behavior over an 8-hour period when exposed to ambient air and show negligible or limited transmittance changes in other environments. The rate of self-bleaching in these films also depends on their preparation conditions, the electrolytes used in the coloring process, and film thickness and roughness. Self-bleaching in a WO{sub 3} film colored by lithium ions can be attributed mainly to the reaction between Li{sup +} ions and water vapor, but self-bleaching in WO{sub 3} films colored by protons may be mainly due to the reaction between H{sup +} and oxygen. The fast self-bleaching of the films in their early stages is dominated by the reaction of surface Li{sup +} or H{sup +} ions which are in direct contact with the reactive gases. The rate of self-bleaching increases with increasing film surface roughness but decreases with film thickness. The latter stages of self-bleaching exhibit a slower transmittance increase and are limited by diffusion of the reaction species.

• DOE Contract Number: AC36-83CH10093
• OSTI ID: 201305
• Report Number(s): CONF-930722--; ISBN 0-8194-1266-X
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
BLEACHING
ELECTROCHROMISM
EXPERIMENTAL DATA
HYDROGEN IONS
MATHEMATICAL MODELS
MICROSTRUCTURE
ROUGHNESS
TUNGSTEN OXIDES
WINDOWS