
Tungsten trioxide may be applied for manufacturing thermal insulation coating. And the widely accepted mechanism of discoloration of WO3 is the dual charge injection/extraction model (inter-band transition of electrons) proposed in 1975. The dual charge injection/extraction model was first discovered and proposed in the electrochromic study of WO3 and was later widely used to explain the photochromic performance of WO3. When tungsten trioxide is irradiated by ultraviolet light, electrons in the valence band are excited into the conduction band, leaving…