Synthesis of VO2 nanoparticles by a hydrothermal-assisted homogeneous precipitation approach for thermochromic applications

Abstract

Thermochromic VO₂ particles, which have potential applications in “smart windows” for energy saving, have been successfully prepared by a convenient route combining homogeneous precipitation and hydrothermal processes. As a result, the particle size can be easily tuned from several tens to hundreds of nanometers by controlling the initial vanadium source concentration. Lower concentration yielded large rod-like crystals, while high concentration resulted in small near-spherical nanocrystals. The decrease of the size of VO₂ particles leads to an improvement in thermochromic properties, along with a wider hysteresis of the phase transition temperature. In addition, the W-doping can effectively tune the phase transition temperature (T_c) down to ambient temperature with the efficiency of about −21.3 °C per at% W in the doping range from 0 to 2.0 at% W.