Structural and Optical Properties of Tungsten Oxide Based Thin Films and Nanofibers

Tungsten oxide nanomaterials confined to one and two dimensions can be prepared with tungsten metal powder, tungsten chloride, peroxotungstic acid and acetylated peroxotungstic acid precursors by sol-gel, evaporation and electrodeposition techniques. Nanofibers and nanowires of tungsten oxide are synthesized by organic/inorganic blend of tungsten hexachloride, tungsten metal powder and polyvinylpyrrolidone with electrospinning technique. Standard and mesoporous tungsten oxide thin films are prepared from an ethanolic solution of tungsten hexachloride. Several polymers were employed as a template to generate the mesoporous structure. Additionally a detailed systematic study of the evaporated tungsten oxide thin films has been carried out at progressively increasing temperatures. Overall, the optical, electrochemical and structural properties of the deposited films were examined in both liquid and solid electrolytes. All solid electrochromic devices were fabricated using tungsten oxide active electrochromic layers. The fabrication and evaluation of a prototype solid-state electrochromic device are also described.