Rapid post-annealing effect on the TiO2-based electrochromic films

Abstract

The electrochromic (EC) window is a promising energy-saving smart window that can vary between three states: transparent, translucent, and opaque by applying low voltages. One of the potential EC materials is known as titanium dioxide (TiO2) due to its unique chemical and physical properties. Conventional post-annealing has been commonly employed for phase transition in EC thin films, but it suffers from drawbacks such as long treatment time and high energy consumption. Hence, in this study, TiO2 thin films were deposited on indium-doped tin oxide (ITO) and fluoride-doped tin oxide (FTO) glass substrates using a sol-gel spin coating technique, followed by a rapid post-annealing interval of 5 min at temperatures ranging from 300 to 450 °C. The optical, morphological, structural, and EC properties of TiO2 thin films were investigated. The measurement depicted that rapid post-annealing was a cost-effective and time-saving method for realising high-quality TiO2 EC thin films. Hence, this approach reduces the overall fabrication time and minimises energy consumption, rendering it an environmentally friendly process. The successful deployment of TiO2 in EC applications paves the way for integrating EC and photovoltaic technologies in energy-saving window glass applications, considering TiO2 is a crucial element in photovoltaic devices.