Ti-Doped WO3 synthesized by a facile wet bath method for improved electrochromism

Electrochromic materials could modulate the optical transmittance reversibly by the application of electric potential and the increase in the surface area for fast ionic diffusion is an efficient way to improve their electrochromism. In this work, WO3 based nanomaterials with a size as small as 5 nm were synthesized via a facile wet bath method that leads to Ti doping of WO3 based on the heterovalency of W(VI) and Ti(IV). Ti doping improved the WO3 electrochromism effectiveness in transmittance contrast and coloration efficiency due to the reduced crystallite size and therefore an increase in the surface area, the Ti doping also enhanced the cycling stability benefiting from the stable Ti-O bonding. However, the coloring/bleaching kinetics were deteriorated due to the reduced proton diffusion coefficient after the Ti ion substitution into the WO3 lattice. A high coloration efficiency of 106.6 cm(2) C-1 and a good optical contrast of similar to 67.6% can be obtained for the optimized Ti-doped WO3 at a wavelength of 633 nm.