Transition metal oxide films: Technology and Smart Windows electrochromic device performance

A smart window is a device controlling the energy of solar flux entering building or car and makes the interiors comfortable and the solar energy utilization more effective. We have developed an optimized APCVD technology for thin film deposition on conductive glass. The films are capable to change their transmittance if a small voltage is applied across the film. The paper deals with the optimization of basic elements of electrochromic device: a working electrode of WO3-MoO3 film, a counter electrode of MoO3-CrO3 film, and polymeric electrolyte between them. The extensive research done on these materials led to conclusion, that WO3-MoO3 combines the excellent electrochromic performance of WO3 and the high-growth-rate of MoO3, when fabricated by the carbonyl APCVD process. A color efficiency in the order of 150-200 cm(2)/C and an optical modulation 40-50%(transmittance difference in bleached and color state) were achieved. APCVD Mo/Cr oxide films were developed to serve as counter electrode. They are optically passive. Results from the voltammetry measurements of the electrochromic performance are related to film structure and optical properties analyzed by Raman spectroscopy, FTIR and spectrophotometry techniques. Emphasis was given on polymeric electrolyte, its composition, technology for preparation, and influence on the EC properties. (C) 2011 Elsevier B.V. All rights reserved.