Effect of Co-doping on the electrochromic performance of hexagonal phase WO₃ nanorods

In this study, cobalt-doped hexagonal phase WO₃ nanorods were prepared by a template-free hydrothermal method. The effects of varying the cobalt doping concentration on the microscopic morphology and electrochromic properties of hexagonal phase WO₃ films were investigated. Films synthesized with the optimal cobalt element doping concentration demonstrate a notable improvement in their electrochromic properties compared to the pure hexagonal phase WO₃ films. The film doped with 1.5% Co exhibited excellent cycling stability, retaining 98.55% of its original value after 500 cycles. The introduction of cobalt results in the formation of a nanorod structure with a high specific surface area within the film. This structure provides additional reaction sites for the electrochromic reaction process, thereby enhancing the optical modulation and coloration efficiency of WO₃. The resulting films with excellent electrochromic properties provide a convenient and effective means for ion-doped modification of WO₃-based electrochromic films.