Abstract: WO₃ sol(600 mL) was prepared with tungsten powder and 37% H₂O₂ through the sol-gel method in this paper. WO₃ thin films were prepared on silicon chips and ordinary slide glasses via Dip Master method and annealed in ambient air at temperatures of 50, 150, 250, 350 and 450 ℃, respectively. Thickness and refractive index of the WO₃ thin films were researched by Spectroscopic Ellipsometer. Surface morphology and microstructure of the films were analyzed with AFM, IR and XRD respectively. The annealing temperature have an important effect on the structure and gaschromic properties of WO₃ thin films. At low annealing temperature, WO₃ thin films is amorphous and porous structure, and the water of WO₃ thin films is appropriate, then this kind of WO₃ thin films have a good gaschromic properties.

Key words: WO₃ thin Films, WO₃ thin Films, Annealing temperature, Annealing temperature, Gaschromic, Gaschromic