WO3 thin films were fabricated by an electrophoretic deposition (EPD) process and prepared at various applied currents ranging from 10 to 40 mA. The surface morphology and thickness of the as-deposited WO3 films depended on the current applied during the EPD process. The surface roughness decreased and the film thickness increased with an increase in the applied current. The electrochromic properties were investigated using chronocoulometry, transmittance measurements, and cyclic voltammetry. Sample C prepared at 30 mA showed the best performance with a coloration efficiency of 17.3 cm2 • C-1. The same film exhibited the lowest W6+/W4+composition area ratio confirmed by X-ray photoelectron spectroscopy data, indicating an increase in the non-stoichiometry of WO3.

Keywords: Electrochromic materials, Electrophoretic deposition, Tungsten trioxide, Transmittance, Coloration efficiency.