Electrochromic Properties of Sol-Gel Deposited Electrochromic TiO2 Thin Films

Abstract

Electrochromic (EC) smart windows are a type of glass window that can change from transparent to darker colour shades when a small voltage is applied. Titanium dioxide (TiO₂) can be utilised as an EC material for EC smart windows. Although the TiO₂ sol-gel spin-coating method is commonly used, the effect of the number of TiO₂ layers was not reported. Thus, this paper investigates the effect of the number of TiO₂ layers. The increasing number of TiO₂ film layers demonstrated a noticeable increase in the thin films ‘anodic and cathodic diffusion coefficient, particularly with 11 TiO₂ layers. Additionally, the colouration and bleaching time was revealed to have a low correlation as the number of layers increased. Nonetheless, the lower number of TiO₂ layers resulted in lower colouring transmittance. Comparatively, the colouration efficiency for all films did not exhibit any significant change. Hence this study on the effect of the TiO₂ layering technique can open a new pathway in understanding the EC properties of TiO₂-based EC devices.