The characters of WO3 electrochromic film prepared by sol-gel method

Electrochromic device is made up of transparent conduction layer, electrochromic layer, electrolyte layer and counter electrode layer. In this paper, we used a sol-gel method, which could decrease the cost, to prepare the WO
₃
electrochromic film. We firstly spin-coated the precursor on the ITO glass and then annealed the WO
₃
film at different temperature. Finally, we covered the electrolyte layer on the WO
₃
film and assembled it into electrochromic device. The film was investigated by Scanning electron microscope (SEM), X-ray diffraction (XRD) and UV spectrophotometer. We found the precursor's color will change from yellow to white after it was stirred over 4h. After comparison, the film annealed at 573K could get the highest contrast ratio.