Electrochromic properties and Raman spectroscopy analysis of tungsten oxide thin film by RF sputter

This study utilizes tungsten oxide as the research subject and investigates changes between different argon/oxygen gas flow ratio and deposits on ITO substrates through RF reactively sputtering. Propylene carbonate (PC) is further mixed with LiClO ₄ for the preparation of electrolyte. After packaged into components, electric voltage is applied to the films to generate reduction or oxidization, which can obtain different colored/bleached states. Lastly, Raman spectroscopy analysis is performed to get a greater understanding of electrochromic mechanisms. The results of the experiment discovered that as-deposited tungsten oxide thin film shows the formation of W ⁺⁶ states, and the application of driving voltage causes the formation of W ⁺⁶ states. At the same time, the thin film coloring effect appears. Increases in driving voltage cause the gradual conversion of W ⁺⁶ states into W ⁺⁶ states, which further leads to a more significant coloring effect. On the other hand, W-O-W deformed crystal lattice structures are also produced, which also affects the incidence of electrochromic property.