In this work 1% Fe-doped tungsten trioxide WO₃ thin films  have been prepared on glass substrates heated to a fixed temperature of 350 °C, using the spray pyrolysis technique, from an aqueous solution based on ammonium tungstate (NH₄)₁₀.H₂(W₂O₇)₆ with 0.005M concentration. The films were annealed at 400 °C, 450 °C, 500 °C and 550 °C for 4 hours. We used X-ray diffraction (XRD), thickness measurement by stylus profilometer for structural characterizations and UV-Visible spectra in the wavelength range [190nm to 1100nm] for optical characterizations.

The structural characterization of the WO₃ thin films by XRD shows that they crystallize in a monoclinic structure, with a space group P2/n. The lattice parameters of samples annealed at 400 °C for 4hours were: a=7.4017í…, b=7.5703í…, c=7.7323í…, β=91.44 °. The average grain size is of the order of 62 nm and the thickness varies between 271 and 351 nm. The UV-Visible transmission spectra confirm that it is possible to obtain good transparent WO₃ thin films, with a 72% and 81% of transmittance in the visible. From the transmittance spectra, we determined the indirect transition band gap value of 3.68 eV at 450 °C for 4 hours.