Non-equilibrium Spark Plasma Reactive Doping Enables Highly Adjustable Metal-to-Insulator Transitions and Improved Mechanical Stability for VO2

Although vanadium dioxide (VO2) exhibits the most abrupt metal-to-insulator transition (MIT) properties near room temperature, the present regulation of their MIT functionalities is insufficient owing to the high complexity and susceptibility associated with V4+. Herein, we demonstrate a spark plasma-assisted reactive sintering approach to simultaneously achieve in situ doping and sintering of VO2 within a largely short period (similar to 10 min). This enables high convenience and flexibility in regulating the electronic structure of VO2 via dopant elements covering Ti, W, Nb, Mo, Cr, and Fe, leading to a wide adjustment in their MIT temperature (TMIT) and basic resistivity (rho). Furthermore, the mechanical strength of the doped VO2 is meanwhile largely improved via the compositing effect of the high melting-point dopant oxide. The high adjustability in MIT properties and improved mechanical properties further pave the way toward practical applications of VO2 in power electronics, thermochromism, and infrared camouflage.