Nano tungsten oxide is a near infrared absorption material with high transmittance in the visible region. Also, it has strong plasma absorption in the near-infrared region near the visible region.

Tungsten oxide, mainly referred to as WO3-x, is a near infrared absorption material. Experts say that tungsten oxide nanopowder does not have the absorption of near-infrared light, so it needs to be reduced to WO3–x. So, how to reduce the tungsten oxide nano powder into WO3–x?

WO3 electrochromic film may be used to produce a smart window, in which the tungsten trioxide film is prepared from WO3 nanopowder. Specifically, experts say that the WO3 film can be combined with a counter electrode material such as a V2O5 film to form a smart window with better optical properties, and the reaction formula is:

Amorphous tungsten oxide electrochromic film has electrochromic properties, so it can absorb infrared rays. In other words, such film can absorb heat in sunlight to reduce room temperature. And therefore the heat insulating film is often used in the field of buildings or automobiles. Some experts obtained the amorphous WO3 film by sol-gel electrophoresis, and studied the transmittance of the film with the applied voltage.