Preparation of WO3 Thin Film by Successive Dip Coating for Electrochromic and Photoelectrochromic Devices

Here we report the superiority of WO3 thin films prepared by successive dip coating in electrochromic devices. Dip coatings were done on transparent conducting oxide substrates in the WO3 precursor solution a number of times without drying in between the coating steps. This process enabled the fabrication of WO3 films with optimum thickness and large roughness, which led to enhanced performance when they were employed as the electrode in electrochromic devices. We made a further observation by applying these electrodes in photoelectrochromic devices and verified the excellent properties of the successively dip‐coated WO3 films.