Cesium desorption mechanism in Cs0.33WO3 by first-principles molecular dynamics calculations

Cesium-doped tungsten bronze, CsxWO3 (CWO), has the property of absorbing near-infrared (NIR) light and transmitting visible light and is used as an NIR shielding material for window glasses. However, the NIR shielding ability of CWO deteriorates with color bleaching in a high-temperature and high-humidity environment, thus limiting its applications. Decolorization is induced by the desorption of Cs in the presence of H2O. This reaction was investigated based on first-principles molecular dynamics calculations and the potential–pH diagram. The results clarified the mechanism of the Cs desorption reaction from a microscopic viewpoint. Furthermore, a countermeasure to suppress the Cs desorption, which employs the steric hindrance effect of cation substitutions with large ions on the surface, was proposed.