Abstract

Metallic Mo powder and Ti(OBuⁿ)₄ were separately dissolved in H₂O₂ solution and the solutions obtained mixed in different Mo/Ti atomic ratios to prepare precursor solutions. Fresh gels obtained from the precursor solutions with > 40% Mo became blue upon exposure to ambient light. X-Ray photoelectron spectroscopy (XPS) was used to examine the chemical states and compositions of the resultant blue-tinged xerogel powders. Based on the XPS results, it is proposed that TiO₂ particles and surface species, including adsorbed water and organic residue, all contribute to the photochromic effect of MoO₃. Mo–Ti oxide films were spin-coated on ITO-coated glass substrates using a precursor solution containing 70% Mo. The cycling behaviours of the films annealed at 150 °C for 1 h were studied using cyclic voltammetry (CV) in propylene carbonate solution containing 1 mol L⁻¹ LiClO₄. The electrochromic properties of the films upon lithium intercalation were investigated by in situ monochromatic transmittance measurements during the CV process, as well as ex situ in the UV/Vis region. The Mo–Ti oxide films were found to possess excellent electrochromic properties upon Li⁺ ion insertion/extraction.