Element doping: a marvelous strategy for pioneering the smart applications of VO 2 .

Smart materials are leading the future of materials by virtue of their autonomous response behavior to external stimuli; it is widely believed their development and application will bring a new revolution. Among them, vanadium dioxide (VO 2 ) is a special one showing a unique multi-stimulus responsive metal-insulator transition (MIT) accompanied by a structural phase transition (SPT) with striking changes of physical properties including optical, electrical and thermal properties, etc ., making it ideal for smart windows, micro-bolometers, actuators, etc . Since the attractive performances of VO 2 are rooted in MIT behavior (coupled with SPT), element doping becomes a powerful tool in tailoring VO 2 performance. Oriented on the practical requirements, element-doped VO 2 is more promising and competitive in terms of performance, prospect, and cost. Here we focus specifically on element-doped VO 2 , the recent progress and potential challenges of which are discussed. We devote attention to the crucial roles of element doping in modulating the properties and driving the practicality of VO 2 , aiming to inspire current research to pioneer new applications of VO 2 .