The structural and optical properties of tungsten oxide films and doped tungsten oxide films with transition metal oxide

Electrochromic, structural and optical properties of zirconium oxide mixed tungsten oxide films with respect to heat treatment temperature were investigated. 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 nkd analyzer. The films are amorphous and 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. The optical properties of sol-gel spin coated zirconium oxide mixed WO₃ thin films have been measured as a function of heat treatment temperature. The refractive index at λ=550nm increased from 1.92 to 2.19 ± 0.01 when heat treatment temperature increased from 200°C to 400°C for tungsten oxide films. The optical band gap value of WO₃ (200°C), WO₃-ZrO ₂ (200°C) and WO₃-ZrO₂ (400°C) were found to be 3.46, 3.53 and 3.51 eV respectively.