Temperature tunable Studies of thermochromic VO₂ and W-VO₂ hybridizised with Flexible IR - 1D Photonic crystals for energy efficent smart windows

The effect of flexible Infra-red 1D photonic crystal as a spectral selective tunable device with Vanadium dioxide as a phase changing material for smart windows application is being studied. Vanadium Dioxide goes under semiconducting to IR - blocking metallic Phase transition around 68º C due to change in its crystal structure from monoclinic to rutile. Monoclinic VO₂ nanostructures with tuned crystallinity due to ambient change is studied. VO₂ thin films were incorporated with 40 % transmitting DBR. Influence of DBR stacking is also being studied, and by slight increase in no. of stacks, nearly 100% reflecting DBR is fabricated, the optical transmission of metallic VO₂ films on DBR with increase in temperature nearly vanishes in the near-IR spectrum and make it a perfect Photo absorber in IR region. To make these energy efficient smart window design more practical, the transition temperature of VO₂ is reduced to near room temperature by doping with tungsten, which is the most suitable dopant for temperature reduction. 1.1 at. % W - Doped VO₂ were synthesized to brought the temperature of IMT transition to 37 ºC from 68 ºC. W-VO₂ nanostructures were incorporated with Infra-red Flexible 1-D photonic crystal and optical transmission vanishes completely with corresponding reflection decrease, this made these structure as spectral selective tunable device which can efficiently control the optical modulation of W-VO₂ nanostructure with change in temperature.  W-VO₂/DBR hybrid structure can substantially control the heat flux and also offers retrofitting application for energy economy.