Synthesis and characterization of tungsten oxide films by electrodeposition with various precursors and electrochromic device application

Abstract

Peroxotungstic acid as well as acetylated peroxotungstic acid has commonly been utilized as precursors in electrodeposition technique to prepare tungsten oxide thin films. However, the use of tungsten chloride in electrodeposition, which is a common precursor for sol–gel application, has not been reported in the literature, to the best of our knowledge. In this manuscript, we sought to prepare tungsten oxide thin films from these precursors through electrodeposition technique on indium tin oxide glass substrate, and then their electrochemical, structural and optical properties were investigated. Based on our results, we refer to tungsten hexachloride as an innovative precursor. Compare to others as thin films from tungsten hexachloride these (i) have more charge insertion and extraction than those synthesized with other precursors, (ii) are deposited in relatively shorter time, less effortlessly, (iii) require lower initial potential than the other films did. Another result of this study is that acetylated peroxotungstic acid solution, obtained from sodium tungstate, had colored on the indium tin oxide surface, without forming a film presenting type I electrochromic properties. Herein, we should note that this electrochromic behavior, depending on the acidification level of the solution, offers large optical modulation and has not been reported in the literature.