Using yellow tungsten oxide as a raw material, invisible warm clothing can be produced. We know that some professional and special people who want to be able to blend in with the colors of the environment. For example, when the snipers are fighting, they want to be the same color as the surrounding background. This can greatly reduce the probability that they will be discovered by the enemy, in order to be able to save their lives. This is a problem we cannot ignore. Today, with the help of high technology, American researchers have made great progress in putting relevant stealth warm clothing on the relevant technology. Yellow tungsten oxide warm coat has a certain invisible effect. Because yellow tungsten has photochromic characteristics. So what is the mechanism of photochromism? What factors are responsible for photochromism?

The mechanism of discoloration of nano tungsten can be explained by the double charge injection. Under ultraviolet irradiation, the valence band is excited into the conduction band, and electron-hole pairs are generated, and then the photoelectrons are captured by hexavalent tungsten to form pentavalent tungsten. At the same time, the photogenerated hole oxidizes the reducing material inside or on the surface of the warm clothing, generates protons, and injects into the interior of the garment, with the reduced blue tungsten bronze.

There are many factors affecting the photochromism of tungsten oxide. In addition to its structure and composition factors, the atmosphere will affect its discoloration performance. Currently studied are the photochromic properties of amorphous (a-WO3) or polycrystalline (c-WO3) films which have excellent photochromic properties. The influencing factors are mainly due to c-WO3 having lattice defects or small specific surface area. From the analysis of the influence of external environmental atmosphere, some organic matter vapors containing hydrogen or hydroxyl groups are beneficial to improve the color reaction speed and absorption intensity of tungsten oxide, which are helpful for improving the photochromic performance of tungsten oxide. Conducive to the production of better performance photochromic materials.