Uses
Tungsten-doped vanadium dioxide (W:VO2) with 1.9% tungsten content has been investigated for use as a "spectrally-selective" window coating to block infrared transmission and reduce the loss of building interior heat through windows. This material behaves like a semiconductor at temperatures below 29 °C, allowing more transmission, and like a conductor at higher temperatures, providing much greater reflectivity. Varying the amount of tungsten allows regulating the phase transition temperature. However, the coating has a slight yellow-green color.
Vanadium dioxide can act as extremely fast optical shutters, optical modulators, infrared modulators for missile guidance systems, cameras, data storage, and other applications.. The thermochromic phase transition between the transparent semiconductive and reflective conductive phase, occurring at 68 °C, can happen in times as short as 100 femtoseconds.
Read more about this topic: Vanadium(IV) Oxide