Hydrothermal synthesis of VO2(A) nanobelts and their phase transition and optical switching properties

VO₂(A) nanobelts are successfully synthesised through a facile hydrothermal approach using peroxovanadium (V) complexes and green solvent (ethanol) as the reducing agent without using any surfactants or templates. The as-obtained products were characterised by X-ray photoelectron spectroscopy, X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy. The as-obtained VO₂(A) nanobelts are with typical lengths up to several tens of micrometres, widths about 180 nm and thicknesses about 45 nm on average. The phase transition properties of VO₂(A) was investigated by differential scanning calorimetry, indicating that it exhibits a strong phase transition at around 160.9°C. Furthermore, the optical switching properties of VO₂(A) were first studied by the variable-temperature infrared spectra to the best of author´s knowledge, and it was found that VO₂(A) nanobelts could be used as the optical switch at different vibratory absorption bands.