Selective fabrication of tungsten nano-oxides via submerged photosynthesis with hydrogen peroxide for chromic device application

Abstract Tungsten nano-oxides of WO3 and H2WO4 have been studied as promising candidates for photocatalytic and chromic materials. To date, WO3 and H2WO4 nanoparticles are generally prepared by hydrothermal synthesis, which requires high temperature environment and pH adjustment. In this paper, we report on fabricating WO3 nanoparticles via photosynthesis by UV irradiation of the solution made from dissolving tungsten in hydrogen peroxide. Similarly, we have succeeded in fabricating H2WO4 nanoparticles by changing the concentration of hydrogen peroxide solution. Furthermore, an electrochromic device was fabricated by coating the WO3 nanoparticles on an ITO substrate, and the chromic properties are then confirmed.