Influence of Fe Doping on the Electrochromic Properties of Co-sputtered V2O5 Thin Films

Vanadium pentoxide (V2O5) attracts considerable attention in electrochromism due to its multicolor aspects and high ion storage capacity for the counter electrode. In this work, pure and Fe-doped V2O5 films are deposited by radiofrequency magnetron co-sputtering. The influence of Fe doping on the structural and electrochemical properties of V2O5-based thin films is investigated. Thin films containing up to 7.8 atom % of Fe are obtained without phase impurities. Although this high Fe doping is detrimental to V2O5 electrochromic properties, a proper amount of about 1.7 atom% of Fe leads to an enhancement of V2O5 crystallinity and electrochemical capacity. The higher capacity of a 1.7 atom % Fe-doped V2O5 film is associated with a stronger memory effect property, described as a reversible color persistence in open-circuit conditions. This work contributes to the exploration of Fe doping through co-sputtering and highlights the relevant role of the doping amount on the physicochemical properties of V2O5.