Controllable Synthesis of Porous Vanadium Dioxide Nanostructures

This chapter focuses on the porosity design and controllable synthesis of porous vanadium dioxide (VO₂) nanostructures from the fundamental and experimental aspects, referring to the most recent literature. In the porous design for VO₂ thin films, the degree of order/disorder and the periodicity have a great impact on the performance improvement. Scientists have developed four effective approaches for constructing porous VO₂ thin films: colloidal lithography assembly, polymer-assisted deposition, dual-phase transformation, and freeze-drying preparation. In colloidal lithography assembly, a closely packed monolayer colloidal crystal (MCC) is first used as the sacrificial template for constructing periodic continuous thin films and then the periodic porous structure is attained after the subsequent removal of the MCC template via chemical etching or high-temperature sintering, an attractive approach for preparing periodic porous structures. A newly developed template-free method to prepare nanoporous VO₂ structures is dual-phase transformation, which could give rise to ultrahigh visible transmittance.