Enhancement of VO2 thermochromic properties by Si doping

• Si-doped VO2 films were prepared at a low temperature by magnetron sputtering.
• The grain size and vanadium cations state changed with different Si content.
• Transparency increased by maintaining NIR switching and solar modulation efficiency.
• Phase transition temperature decreased to 46 °C with a doping ratio of Si/V = 0.17.

Silicon doped vanadium dioxide films were successfully prepared on indium tin oxide coated glass substrates at 255 °C annealing temperature by direct current magnetron sputtering. Maintaining spheroidal grains, the size of VO2 films nanoparticles decreased with silicon doping ratios increasing. Transmittance spectra indicated a 46 nm blue-shift of absorption edge and improved the samples' integrated luminous transmittances (from 28.4% at Si/V = 0 to 36.1% at Si/V = 0.17) with similar thickness of 90 nm. The samples presented excellent thermochromic properties that possessed higher than 40% near-infrared switching efficiency at 2000 nm and showed at least 9.2% solar modulation efficiency. Moreover, the metal–semiconductor phase transition temperature for heavily doped VO2 (Si/V = 0.17) decreased to 46.1 °C (22 °C lower than bulk). These features suggest the practical application of VO2 to smart windows.

With Si doping, VO2 samples increased 27% luminous transmittance remaining excellent solar modulation efficiency and decreasing MST temperature to 46.1 °C.Figure optionsDownload high-quality image (230 K)Download as PowerPoint slide