Enhanced electrochromic performance of WO3 nanowire networks grown directly on fluorine-doped tin oxide substrates

Abstract

Electrochromic devices have shown enhanced performances when constructed with nanostructured crystalline materials due to increased surface area and improved stability. A thin film of hexagonal WO₃ nanowires was grown directly onto a bare fluorine-doped tin oxide glass (FTO) without the assistance of a WO₃ seed layer via a facile and low-cost solvothermal method. Compared with the WO₃ film synthesized with a seed layer, a faster switching time, higher coloration efficiency and more stable cycling were achieved due to direct nanowire contact with the substrate. In order to improve the contact between the WO₃ and FTO, and therefore increase the stability of the electrode, it was annealed under N₂ and the time of cycling stability increased by almost a factor of 10.