Preparation, characterization and properties of thermochromic tungsten-doped vanadium dioxide by thermal reduction and annealing

Thermochromic tungsten-doped vanadium dioxide (VO2) powders were successfully synthesized by thermal reduction using V2O5 as a vanadium precursor. The products were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The results indicated that W was successfully doped into the crystal lattice of VO2 matrix, and prepared tungsten-doped VO2 had a rod-like morphology. The effects of reducing temperature and annealing temperature on the crystallographic structures were also discussed. The phase transition temperature (Tt) of VO2 could be simply tuned by changing the doping concentration of tungsten. When the doping concentration was 1.58 mol%, the Tt could be reduced to 37.8 °C from initial 69.5 °C, suggesting that tungsten-doped VO2 possesses prominent thermochromic properties and optical switching characters. It has shown that this convenient and efficient approach could be applied in the mass-production of functional powders materials.