Tungsten trioxide is a new type of electrochromic material that is able to reversibly and persistently change its optical properties at an external voltage. Tungsten trioxide is considered as one of the most promising candidates for fabricating energy-saving smart window.

It has been reported that some experts fabricated nanocrystalline tungsten oxide based NO2 sensor by thin film microfabrication technique. And the sensitivity of this NO2 sensor was at parts per billion (ppb) level.

Tungsten oxide nano-urchins are paid much attention due to good electrochromic performance. You know, tungsten oxide as an inorganic electrochromic material has attracted considerable attention as it is promising in applications of electrochromic glass - energy-saving smart glass having high shielding performance to near-infrared rays and high transmittance to visible light.

W18O49 is an important material for fabricating infrared-shielding film, to sufficiently transmit visible rays and shield invisible near-infrared rays. Some experts prepared W18O49 powder by heating a mixture containing a predetermined amount of a tungsten compound at 550 °C in a reductive atmosphere for 1 h, then cooled to room temperature once in an argon atmosphere.

It has been reported that amorphous tungsten oxide thin film has good optical absorption to shield near-infrared rays, thereby reducing room temperature in hot summer and saving powder rate for cooling the room by using air conditioners or fans. Some experts have investigated the electrochromic color centers of amorphous tungsten oxide thin film by the Raman scattering method.

Sputtered tungsten trioxide, more specifically, sputtered WO3 film, may be applied as a photoelectrode to obtain high solar-to-hydrogen efficiency. Some experts have prepared tungsten oxide film with a dense, compact morphology at a temperature lower than 250 °C by reactive sputtering from tungsten targets in an argon/oxygen ambient in the context of photoelectrochemical water-splitting.

It has been reported that some researchers prepared electrochromic tungsten trioxide film by spray pyrolysis under various conditions using tungsten chloride (WCl6) to dissolve in 50% ethanol–50% water. And it was found that all the as-deposited electrochromic tungsten trioxide films were amorphous and dark. When annealed, they became crystallized and transparent. In the preparation process, the researchers also studied the structure and the composition of these films, before and after annealing.

Recently, tungsten-oxide-based material has received considerable attention among various photothermal nanomaterials because of its ability to absorb near-infrared light and its efficient light-to-heat conversion properties. In addition, tungsten-oxide-based material has an unusual oxygen defect structure and strong surface plasma resonance, which offers strong photoabsorption in a broad wavelength range of the near-infrared light region.

Some experts have proposed a preparation method of inorganic all-solid WO3 electrochromic device. Wherein, the inorganic all-solid electrochromic device has a nickel oxide-zirconia-tungsten oxide stacked structure, and silver nanowires are spin-coated on the stacked structure.

Tungsten oxide is an idea material for NO2 sensing. It has been reported that tungsten oxide based gas sensors exhibit excellent NO2 sensing properties to cover environmental standard of NO2. The experts have done researches to investigate several properties of nano crystallites of tungsten oxide including NO2 sensing characteristics.