Tungsten trioxide film can be used to prepare a large area smart glass as the WO3 material itself has good electrochromic properties. And the technology of large-area electrochromic glass is one of the main technologies required for building energy efficiency today.

Tungsten oxide film can be used to prepare an all-solid-state electrochromic window. Specifically, such an electrochromic device is assembled using an inorganic transition metal oxide (mainly tungsten trioxide) as an electrochromic material, and an inorganic lithium-containing compound or an organic polymer as an electrolyte layer.

Yellow tungsten oxide electrochromic film, also known as tungsten trioxide film, can be used to assemble an all-solid-state electrochromic window. Wherein the tungsten trioxide electrochromic thin film can be prepared by a hydrothermal method. The following are the preparation steps of the WO3∙0.33H2O film:

Tungsten trioxide film for producing an all-solid-state electrochromic window can be prepared by a sol-gel method in electrochemical and wet chemical methods. Certainly, there are many other preparation methods for electrochromic materials. These preparation methods commonly used at home and abroad include vacuum evaporation method, sputtering method, chemical vapor deposition method, ion plating technology, and electrochemical deposition method. The following is something about the sol-gel method.