Optimized sol-gel synthesis of WO3 hydrogel for obtaining electrochromic films

This paper looks at the synthesis of thin WO3 films with electrochromic properties by peroxide sol-gel method. In particular, the paper considers an optimized process of drying the polyperoxotungstic acid solution after evaporation. In the course of this research, the authors substantiated and carried out volume drying and vacuum compaction of specimens placed in special design plastic containers. It is shown that the final product – i. e. amorphous WO3 hydrogel – has good solubility in ethyl alcohol. The paper considers how the products of drying the polyperoxotungstic acid solution after evaporation are being formed. The obtained product – i. e. WO3 hydrogel – was analyzed by means of differential thermal analysis in the temperature range of 20 to 500 oC at the heating rate of 5 degree/min in air. The authors used the method of X-ray diffractometry with the Cu Kα radiation from 10 to 60 degrees at the rate of 5 degree/min to examine the degree of WO3 hydrogel amorphism.