Optical properties of vanadium dioxide thin film in nanoparticle structure

Abstract The thermo-optic effect and infrared optical properties of VO 2 nanoparticles were studied to obtain an optical material with special property that can be used in smart windows. The reflectance and transmittance spectra of the VO 2 nanoparticles with different duty cycles at different temperatures were simulated with a specific dispersion relation. Vanadium metal nanoparticles were deposited on glass substrate by magnetic reactive sputtering with porous alumina template (AAO) mask, and the VO 2 nanoparticles were prepared by thermal oxidation. The nanostructure and optical properties of the VO 2 nanoparticles were characterized by atomic force microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and spectrophotometry. The method of preparation of the sample is economical and the phase transition temperature is observed to drop to 43 °C. The transmission at 1700 nm exhibits a variation of 29% between the metallic and semiconducting states. The VO 2 nanoparticles exhibit a significant thermochromic property. The transmittance of the VO 2 nanoparticles is improved compared with the VO 2 film. The decrease in phase transition temperature and the enhancement of optical properties demonstrate that VO 2 film in nanoparticle structure is a viable candidate material for smart windows.