Synthesis, microstructure, and phase transition characteristics of Gd/Nd-doped nano VO₂ powders

Abstract The nano VO2 powders were prepared by hydrothermal synthesis. The effects of Gd and Nd element doping on the structure and phase transition temperature of VO2 were studied. The X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), and Transmission electron microscopy (TEM) results showed that Gd element and Nd element will affect the structure of VO2. Gd3+ and Nd3+ can occupy partial position of V4+ lattice and form solid solution, increasing the lattice parameters of VO2. Both the doped and un-doped VO2 powders exhibit a monoclinic structure at room temperature. Due to the lattice deformation caused by Gd or Nd doping, the aggregation of particles is prevented, and the grain is refined obviously. Differential scanning calorimetry curves showed that both Gd doping and Nd doping can reduce the phase transition temperature of VO2(M). When the Gd doping concentration is 6 at%, the phase transition temperature can be reduced from 71.7°C to 60.3°C, and the infrared transmittance before and after the phase transition also changes significantly, reaching more than 40%. Nd doping is similar, and the phase transition temperature decreased to 55.6°C with the addition of 9 at% Nd.