
Nano grain size tungsten trioxide may be used to manufacture thermal insulation coating, and therefore be applied in thermal insulation glass, such as building glass and car window glass. The glass will turn blue when sun shines on such glass. The reason why tungsten trioxide turns blue is the result of the transition of electrons in the W(V) valence band to the W(VII) conduction band. The double charge injection/extraction model, which was proposed in 1975, is the widely accepted model…