In-situ solvothermally grown hexagonal tungsten oxide films on FTO coated glasses for electrochromic applications

Hexagonal tungsten oxide films were directly synthesized on fluorine-doped tin dioxide (FTO) coated glasses by the solvothermal method. The tungsten oxide films prepared by using glutaric acid as a self-crystallizing seeding agent and thiourea as a structural guide have a porous morphology with interwoven nanowires. The as-prepared films show excellent electrochromic performance in 1 M sulfuric acid, including 53 % optical modulation at 633 nm by applying ± 0.3 V, fast switching speed of 5 s for coloring and 2 s for bleaching, and high coloring efficiency of 144 C −1 cm 2 .