Abstract
Vanadium oxide is one of the most interesting materials for electrochromic applications thanks to their both anodic and cathodic electrochromism and multicolor display. In this study, we have successfully synthesized vanadium oxyhydroxide H2V3O8 with mixed valence states (V5+ and V4+) from hydrothermal synthesis. Electrochromic vanadium oxyhydroxide thin films were deposited by dip coating from the homemade powders. Film structure and morphology were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM) while their electrochemical and optical properties are investigated by cyclic voltammetry (CV) and in situ transmittance. H2V3O8 thin film demonstrated good reversibility and durability upon 400 cycles, high transmittance modulation, and good coloration efficiency (CE approximate to 76.35 cm(2) C-1) at 550 nm and characterized with fast switching speeds (2 s for coloration and 3 s for bleaching). The nice color switch appears well suitable for smart windows application.