When it comes to the phenomenon of electrochromism, many people think of yellow tungsten oxide film (WO3 film) - an earliest and most studied inorganic electrochromic film material. Well, do you know what the electrochromic mechanism of crystalline WO3 film is? And what is the electrochromic mechanism of amorphous WO3 film?

Electrochromism refers to the phenomenon that optical properties such as transmittance and absorption of electrochromic materials undergo a stable and reversible color change under the action of an applied electric field. It means that electrochromism can occur in yellow tungsten oxide nanocrystalline composite film - an electrochromic material.

Yellow tungsten oxide nanorods for application in electrochromic film are WO3 nanorods that can be synthesized by solvothermal method. For example, some experts have synthesized monodisperse tungsten oxide nanorods by solvothermal method. Wherein, the experts prepared tungsten oxide nanorods of different size by adjusting the concentration of oleylamine in the precursor, and the size of the nanorods increased from 38nm x 3.2nm to 89nm x 4.5nm. Then, the WO3 nanorods electrochromic film was constructed by heat treatment at a certain temperature.

It is reported that some experts have prepared yellow tungsten oxide nanofibers (WO3 nanofibers) via electrostatic spinning with an average diameter of about 200nm. Wherein, WO3 nanofibers consist of a large amount of tungsten trioxide nano particles. These experts also studied the gas sensitivity characteristics of WO3 nanofibers-based gas sensors to H2S.