Property of thin film material composed by single substance usually can not meet the actual requirement, so doped tungsten oxide thin film with different element will improve some of its characteristics including mechanics, electricity, optics, chemistry and structure or morphology, which will also be different by doping amount and different doping material. In essence, doping will cause changes in energy level and energy band of impurities, also the carrier concentration of crystal, which results in the change of crystal structure.
Tungsten oxide thin film with doped element will improve some of its properties greatly. For example, after doped with a certain amount of Pt and Pd, the hydrogen sensitive of thin film will improve and reduce the reaction time. Li-doped tungsten oxide thin film will improve its electrochromic property especially the speed of coloring and fading. Ag-doped tungsten oxide thin film will increase sensitivity for SO2. TiO2-doped tungsten oxide thin film will reduces its flaw. Ni and Co doped tungsten oxide thin film will lower its polarization voltage which will increase the stability.