Recent progress in vanadium dioxide: The multi-stimuli responsive material and its applications

The reversible phase transition in vanadium dioxide (VO2) with light, heat, electric, magnetic, and mechanical stimuli is the enabling concept to function as a smart material. It is the basis for the development of numerous varieties of VO2-based optical, electrochemical, electrical, mechanical, and energy storage devices in micron-to nano-meter scale dimensions on rigid and flexible platforms. Due to its near room temperature (RT) phase transition, VO2 is considered an excellent alternative and promising candidate to replace the conventional ma-terials used in various applications. Ample interests have been growing to apply VO2 in novel devices, exploring the device functionality by structural manipulation of VO2 that could lead to impressive innovations. Much effort is invested in resolving the practical challenges to deal with real-life applications, along with finding out industrially feasible large-scale VO2-based device fabrication methodology which may act as a stepping stone to embark on the commercial market. In this context, it is crucial to review the recent advancements in devices that use VO2 smart material as a building element in the device architecture along with the device operation controlled by the phase transition mechanism in VO2. This review summarizes the new applications of VO2 in various devices. We start with a brief introduction of the present landscape of various phase transition mecha-nisms involved in VO2 followed by significant advantages of VO2 as a functional material for various applica-tions. In the main part of the paper, the recent five years' progress in VO2-based single-stimulus, multi-stimuli, and multifunctional devices, their operation mechanism, and important experimental and theoretical break-throughs are summarized under each device. Although VO2 plays a significant role in controlling the device operation, various practical challenges are there to be rectified to further enhance the device performance that would accelerate VO2-based devices in reaching the commercial platform. Future trends, possible challenges in VO2-based devices, and potential solutions are presented with perspectives in the final part of the paper.