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

Thermochromic tungsten-doped vanadium dioxide (VO 2) powders were successfully synthesized by thermal reduction using V 2O 5 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 VO 2 matrix, and prepared tungsten-doped VO 2 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 VO 2 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 VO 2 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.