The solution growth route and characterization of electrochromic tungsten oxide thin films

Electrochromic tungsten oxide thin films were prepared by using an aqueous solution of Na₂WO₄·2H₂O and dimethyl sulfate. Various techniques were used for the characterization of the films such as X-ray diffraction, cyclic voltammetry, SEM analysis and VIS-spectroscopy. The thin film durability was tested in an aqueous solution of LiClO₄ (0.1 mol/dm³) for about 7000 cycles followed by cyclic voltammetry. No significant changes in the cyclic voltammograms were found, thus proving the high durability of the films.The optical transmittance spectra of coloured and bleached states showed significant change in the transmittance, which makes these films favorable for electrochromic devices.