Phase transition and IR properties of tungsten-doped vanadium dioxide nanopowders

Thermochromic vanadium dioxide exhibits a semiconducting to metallic phase transition at Tt = 341 K, involving strong variations in electrical, magnetic, optical transmittance. Tungsten-doped vanadium dioxide nanopowders were synthesized by thermolysis with slight improvement and active white powdery tungstic acid (WPTA) used as a substitutional dopant. The results show that the phase transition temperature of the doped VO2 powders were decreased to 298.6 K, which is very close to the room temperature. Tungsten-doped has enhanced the IR properties of VO2 nanopowders because the contrast of its IR transmission below and above the room temperature is up to 92% in our experiment.