Cobalt ions doped tungsten oxide nanowires achieved vertically aligned nanostructure with enhanced electrochromic properties

Abstract In this research, Co ions doped WO3 films are introduced with modified morphology and enhanced electrochromic (EC) properties by seed free hydrothermal method. Effects of Co dopant on the structure and electrochromic performance of the WO3 films are systematically investigated. It is found that compared with the pure WO3 film, Co ions doped WO3 films present significant variation in surface morphology, and also exhibit much higher transmittance modulation (75.4% at 680 nm and 76.7% at 890 nm), higher CE value (65.7 cm2 C−1) and better long-term stability (over 4000 cycles). The explanation of the enhanced EC performance is mainly attributed to the vertically aligned nanostructure of the films, which provided larger specific surface area, larger number of accessible intercalation sites and rapid ions diffusion. Thus, these Co-doped WO3 nanowire arrays films may offer a promising way for developing materials with high EC performance.