WO3 electrochromic film for new electrochromic window can be prepared by sol-impregnation method. For example, some experts have prepared tungsten oxide electrochromic thin film with good light adjustment ability by sol-impregnation method.
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In the process, the experts found that: At the heat treatment temperature of 500 °C for 3 h, the surface of the obtained electrochromic film is very flat with nano-scale crystal grains, and the coloring-bleaching property is better. In addition, the cyclic voltammetric characteristics of the film are stable, and the ion injection and extraction process are reversible. Further, the difference in the maximum transmittance of the colored state of the film and the bleached state occurs at a wavelength of 750 nm, which is about 45%. In a word, the obtained tungsten oxide electrochromic thin film has a good light-adjusting ability – good shielding performance to infrared rays and ultraviolet rays with high transparency.