Effect of growth temperature on the nanostructure and electrochemical properties of in-situ deposited WO_3 thin films

摘要

Thin films of tungsten trioxide (WO_3) have widespread applications such as in photocatalysis, electrochromism, photochromism, etc. Tuning the nanostructure of WO_3 thin films has a notable impact on their electro/photocatalytic properties. In this work, WO_3 thin films were prepared on FTO glass employing the in-situ hydrothermal method. Amongst other parameters of thin-film growth, the hydrothermal growth temperature is crucial toward WO_3 thin film characteristics. The reaction temperature for the preparation of WO_3 thin films in this study varied from 120 to 180 ℃. XRD analysis revealed that WO_3 thin films prepared at reaction temperatures of 120 (W120) and 150 ℃ (W150) have a hexagonal structure, whereas thin film prepared at 180 ℃ (W180) has a mixed hexagonal and monoclinic structure. The morphology of thin films changed with reaction temperature, as evidenced by FE-SEM analysis. Cyclic voltammetry analysis indicated that W120 exhibited fast Li~+ ions insertion and extraction kinetics as compared to thin films synthesized at other temperatures. Finally, a correlation was made between the better electrochemical performance of W120 with its structure and morphology.