Influence of Fe Doping\non the Electrochromic Properties\nof Co-sputtered V<sub>2</sub>O<sub>5</sub> Thin Films

Vanadium pentoxide (V<sub>2</sub>O<sub>5</sub>) attracts\nconsiderable\nattention in electrochromism due to its multicolor aspects and high\nion storage capacity for the counter electrode. In this work, pure\nand Fe-doped V<sub>2</sub>O<sub>5</sub> films are deposited by radiofrequency\nmagnetron co-sputtering. The influence of Fe doping on the structural\nand electrochemical properties of V<sub>2</sub>O<sub>5</sub>-based\nthin films is investigated. Thin films containing up to 7.8 atom %\nof Fe are obtained without phase impurities. Although this high Fe\ndoping is detrimental to V<sub>2</sub>O<sub>5</sub> electrochromic\nproperties, a proper amount of about 1.7 atom% of Fe leads to an enhancement\nof V<sub>2</sub>O<sub>5</sub> crystallinity and electrochemical capacity.\nThe higher capacity of a 1.7 atom % Fe-doped V<sub>2</sub>O<sub>5</sub> film is associated with a stronger memory effect property, described\nas a reversible color persistence in open-circuit conditions. This\nwork contributes to the exploration of Fe doping through co-sputtering\nand highlights the relevant role of the doping amount on the physicochemical\nproperties of V<sub>2</sub>O<sub>5</sub>.