Nano cesium tungsten bronze is a kind of near infrared shielding material. And the study of the selective transmittance mechanism of cesium tungsten bronze found:
In cesium tungsten bronze, the valence state of tungsten is a mixture of hexavalent (W6+) and pentavalent (W5+), and charge carrier hopping between the two valence states are very likely to occur. When W5+ is oxidized to W6+, lattice vacancies will occur, and the electrons lost by tungsten will occupy vacancies and become color center. When irradiated by a spectrum in a certain visible light region, the electrons present in the color center are excited, thereby producing a color. When the amount of doped positive ions (Cs+) changes, the ratio of W5+ and W6+ in the cesium tungsten bronze also changes, so that the number of electrons undergoing charge carrier hopping changes immediately, resulting in the absorption of light waves in different wavelength bands of visible light.
More details, please visit:
http://www.tungsten-powder.com/cesium-tungsten-bronze-chinatungsten.html
