Characterization of sputter-deposited WO3 and CeO2-x-TiO2 thin films for electrochromic applications

DC magnetron sputter-deposited WO3 and CeO2-x-TiO2 thin films are investiga ted for electrochromic applications. Emphasis lies both on material charact erization and electrochemical measurements. Various surface analytical tech niques are used to obtain detailed information on the relation between thin film properties and charge density as the main electrochemical parameter. Parameters in electrochemical testing, such as the applied voltage, the amo unt of water in the liquid electrolyte and conditions of sample storage, ar e varied to clarify their influence on experimental results. A comparison o f the charge density measured electrochemically and that calculated from we t chemical analysis of etched samples reveals a significant share of proton intercalation, which falsifies the measured values. Furthermore, this pape r contributes to discussions of the intercalation mechanism in CeO2-x-TiO2 with regard to material properties, particularly the binding state (XPS) an d thin film density (GI-XRS). (C) 2001 Elsevier Science B.V. All rights res erved.