Alkali-metal-doped WO3, as a near-infrared shielding material, is often designed for preparing smart windows. According to the experts, the development of new WO3-based material is significantly important for smart window applications.

WO3 is well-known as an electrochromic material for preparing an all solid-state electrochromic window. And such a window is known as a smart window with function of adjusting room temperature. Some experts have studied the all solid-state smart window of electrodeposited WO3 and TiO2 particulate film with PTREGD gel electrolyte.

WO3 is an important functional material for producing high performance energy-saving smart window. It is reported that the WO3/TiO2 core–shell structure possesses superior properties, giving it good potential for use in energy-saving smart windows. For example, some experts have investigated the electrochromic, photodegradation, and photoinduced hydrophilicity properties of the WO3/TiO2 core–shell nanostructure as a smart building material for energy-saving.

Cs0.33WO3-xFx, which is known as an important near-infrared shielding material, may be prepared by the gel-gel method. For example, some experts have prepared Cs and F co-doped Cs0.33WO3-xFx by sol-gel method with using tungstic acid, CsCl, and CsF as raw materials (Cs/W = 0.33), and discussed the effects of different F doping amounts on product phase, morphology, and optical properties.