Post-annealing effect on the electrochromic properties of WO3 films

Abstract The idea of Internet of Things (IoT) has brought about the innovation of smart materials and devices which affect our everyday life. One of the technologies associated to the IoT is the electrochromic (EC) smart windows and the key material is tungsten oxide (WO3). WO3 is considered as the best candidate due to its superior EC properties for example high optical modulation and high colouration efficiency. In this work, the structural properties of WO3 films were manipulated by varying the post annealing temperature between 27 °C and 450 °C. The WO3 films annealed at different temperature were characterised for their structural, morphological, optical and EC properties using X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), optical transmittance study, cyclic voltammetry (CV) and chronoamperometry (CA) measurements. The effect of post annealing temperature will be analysed and investigated which is important for smart window performance optimisation.