Facile one-step deposition of electrochromic WO3·0.33H2O films on ITO substrate under solvothermal condition

•A facile method was developed to directly deposit tungsten oxide films on the ITO substrate under solvothermal condition.•The content of isopropyl alcohol is found to be crucial for the direct deposition of WO3·0.33H2O films to initiate the film growth with different morphologies on the ITO substrate.•The electrochromic properties of these films reveal their promising potential applications in smart windows.

Tungsten oxide films were directly deposited on ITO substrates by a facile one-step method under solvothermal condition using isopropyl alcohol (IA) in the precursor solution. By using X-ray diffraction and scanning electron microscopy, the structural and morphological changes of the film were characterized after introducing different IA contents in the precursor solution. Results show that increasing the IA content leads to increased crystallites grown on the ITO substrate with morphology evolution from dispersed particle-like structure to compact microbricks, and finally to well-aligned nanosheets, indicating a crucial role of IA to initiate the direct deposition of WO3·0.33H2O film on the ITO substrate. Moreover, corresponding electrochromic results further exhibit the fast switch speed and high contrast around near-infrared region of the films, suggesting their potential application in smart windows in the future.

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