High thermochromic performance of Fe/Mg co-doped VO2 thin films for smart window applications

In the field of energy-efficient smart windows, vanadium dioxide (VO 2 ) is a promising material due to its reversible metal-insulator transition. However, the development of VO 2 -based smart windows has been restricted by several drawbacks in performance, including high phase transition temperature ( T C ), low luminous transmittance ( T lum ), insufficient solar energy modulation ability (Δ T sol ) and unpopular color. In this paper, Fe/Mg co-doping is proposed for the first time to improve the thermochromic performance of VO 2 films. Interestingly, the Fe/Mg co-doped films can exhibit outstanding thermochromic performance with a balanced solar regulation efficiency of 12.8%, suitable luminous transmittance up to 42.1%, and low phase transition temperature around 38.2 °C, which is very promising for practical applications. In addition, the color of films is modified to increase their brightness and lighten the brown color. Different from previous work on co-doped VO 2 focusing on W 6+ and low-valence (