Structural and surface analysis of Mo-W oxide films prepared by atmospheric pressure chemical vapor deposition

The study deals with the structure, morphology and the optoelectronic properties of tungsten and molybdenum based oxide films showing high electrochromic performance. The films were deposited by atmospheric pressure chemical vapor deposition (APCVD) technique. The present work is related to optimization of the electrochromic effect through the films electronic composition and through some parameters of the ion intercalation process, depending on the type of electrolyte, respectively type of ions and their concentration, as well as on kinetics parameters, like the scan rate during the voltammometric measurements of the electrochromic effect. X-ray photoelectron spectroscopy (XPS) was used to prove the existence of multivalent states of the corresponding metals in the mixed films. In result of these different metallic states, more intensive transition processes should define higher optical absorption and correspondingly better expressed electrochromic effect. The present study proved this expectation in the case of mixed W/Mo based oxide films. Obtained were excellent color efficiency and optical modulation, exceeding these of WO3 films. (C) 2007 Elsevier B.V. All rights reserved.