Investigation of electrochromic properties of novel tungsten trioxide nano-structure preparation using hydrothermal process

摘要

The purpose of this study is to fabricate the tungsten trioxide (WO3) nano-rod (WNRs) films by hydrothermal process and investigate the relationship between microstructure morphologies and electrochromic properties. A WO3 seed layer with monoclinic structure was deposited on a fluorine doped tin oxide (FTO) coated glass substrate by spin coating. The mixtures of sodium tungstate (Na2WO4), hydrochloric acid (HCl), oxalic acid (H2C2O4) and sodium acetate (CH3COONa, capping agent) were adopted to be the precursors of WO3 films for the hydrothermal process. By a series of experiments, it was found the optimal process parameters were the Na2WO4 concentration of 0.25M, the pH of 2.2, the capping agent of 0.0075mol, the growth temperature of 180??C and the growth time of 2 hr. It revealed the optimal process parameters samples possessed best electrochromic properties is due to having high specific surface area and porous structure which resulted in more easily react with lithium ion (Li+) in the electrolyte.