Electrochromic WO3 films prepared by a new electrodeposition method

Tungsten oxide (WO3) films with good electrochromic properties were prepared by a new electrodeposition method. The structural properties were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The electrochemical and optical properties were measured by cyclic voltammetry (CV) and spectral optical transmittance and reflectance methods. The films are amorphous or microcrystalline depending on the post-annealing temperatures, both of them having a very smooth surface. Different electrochromic properties can be obtained for amorphous and microcrystalline films, with the amorphous one showing good absorption modulation in the visible range and microcrystalline one showing obvious reflectance change in the near-infrared range. Good durability of the deposited films was observed which was very important for the practical applications.