Synthesis and thermal stability of W-doped VO2 nanocrystals

Pure and W-doped vanadium dioxide nanocrystals have been synthesized by using V2O5 and oxalic acid as precursors via a thermolysis method. The VO2 nanocrystals have a nearly spherical morphology with size ranging from 50 to 100 nm. The metal-insulator transition (MIT) temperature of the nanocrystals decreases with increasing W-doping content. The successive heat-induced fatigue character of the MIT in W-doped VO2 nanocrystals was investigated by DSC analysis together with structural study, and a high stability upon heating–cooling cycles was found with respect to MIT temperature, peak temperature and latent heat of the phase transition.

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► The VO2 nanocrystals with a nearly spherical morphology with size ranging from 50 to 100 nm were synthesized by using V2O5 and oxalic acid as precursors via a thermolysis method.
► The W dopant is in the W6+ form, and there is a small amount of V3+ in the VO2 nanocrystals. VO2 (R) nanocrystals with phase transition temperature at room temperature were obtained with 2.5 at% W-doing.
► A high stability upon heating–cooling cycles was observed with respect to MIT temperature, peak temperature and latent heat of the phase transition due to both the size effect and the existence of V3+ in the VO2 nanocrystals.