Research of Optical Performance of VO2/V2O5 Composite Film with Ultra-High Luminous Transmittance

Abstract

The optical performance of vanadium dioxide film is important for the application in smart windows. In this work, we prepared ultra-thin vanadium oxide films with thickness from 30 nm to 120 nm and investigated the influence of thickness on the optical performance of ultra-thin vanadium oxide films. The experimental results show that the composite of vanadium pentoxide (V2O5) with a low refractive index can improve luminous transmittance, which reaches 66.32% at the film thickness of 30 nm. The transmittance of metallic phase ultra-thin vanadium oxide film in the visible band is higher than that in the semiconductor phase, which leads to cross-points in transmittance curve and negative solar energy modulation. With the increase of thickness, the position of cross-points in transmittance curve shifts to long-wavelength, and the absolute value of negative solar energy modulation increases from 0.73% to 1.5%, which is related to the principle of optical interference. These conclusions will inspire ultra-thin vanadium dioxide film in improving the solar energy modulation of smart windows under the high luminous transmittance.