ELECTROCHEMICAL MECHANISMS IN TUNGSTEN-OXIDE THIN-FILMS

Electrochromic WO3 thin films can be deposited via the sol-gel process . According to experimental procedure, amorphous or crystalline oxides can be obtained. The electrochemical behavior of crystalline WO3,2H2O and WO3 has been compared with amorphous WO3,nH2O. The kinetics of th e different processes was followed by cyclic voltammetry and complex i mpedance measurements. Structural changes are observed by X-Ray diffra ction. These experiments show the role of water molecules during the e lectrochemical reaction. Li+ ions remain close to the water molecules in the interfoliar space whereas the whole oxide network is affected i n non hydrated oxides.