Integration of sputtering and solvothermal techniques for the synthesis and assessment of WO3 nanostructure for enhanced electrochromic performance

This study presents the successful synthesis of WO3 nanorods using a combined sputtering and solvothermal approach. The optimization of seed layer deposition time was found to influence the electrochromic properties of the resulting films. The nanorods were synthesized solvothermally on FTO glass substrates which are pre-coated with seed layers using DC magnetron sputtering for durations of 1, 2, and 3 min. Structural characterization revealed a hexagonal crystal structure and pure WO3 composition for all samples, with the 3-min seed layer film exhibiting densely packed nanorods with higher porosity. Electrochromic studies revealed that the 3-min seed layer deposition yielded the most favourable results, exhibiting an enhanced colouration efficiency (CE) of 12.97 cm(2)/C, an optical modulation of 27%, and an optical density of 0.279. Additionally, this film demonstrated superior cycling stability, with nominal degradation in electrochromic performance after 300 cycles. The 3-min seed layer film also had the highest diffusion coefficient (25.81 x 10(-10) cm(2)/s) compared to the 1- and 2-min films. Chronoamperometric studies revealed faster switching times of 1.3 s for colouration and 0.9 s for bleaching in the 3-min seed layer film. These findings underscore the potential of this hybrid method for developing efficient electrochromic materials for applications in smart windows, displays, and energy storage devices.