Tungsten trioxide is an n-type semiconductor material with a narrow band gap (2.4-2.8 eV), is capable of responding to visible light, and has similar characteristics to TiO2 photocatalyst, which is stable, non-toxic, photo-resistant, and low-cost. Its valence band has a high potential and the photo-generated electron hole has strong oxidation ability.

Tungsten oxide is a transition metal oxide n-type semiconductor. As a functional material, in recent years, a large number of studies have found that tungsten-based oxides does not only can be applied as catalysis, electrochromism, battery electrodes, solar absorbing materials and invisible materials, but also has the semiconductor characteristics of heat-sensitive, pressure-sensitive and gas-sensitive.

Photocatalysis is a main measure to control environmental pollution in the future. Since the first use of titanium dioxide photocatalyst by the Japanese in 1972, the field of photocatalysis has experienced nearly half a century of development. At present, photocatalyst materials can be used in various fields and can be used for sewage treatment, air treatment, home environment purification, and even power generation.

Near-infrared light accounts for about 46% of the solar spectrum. In many countries, building energy consumption accounts for about 30-40% of national energy consumption, while energy consumed through glass doors and windows accounts for over 50% of building energy consumption. Building window glass energy-saving and insulation is of great significance for energy saving and emission reduction. Therefore, the development of thermal insulation coatings, especially architectural thermal insulation coatings closely related to human life, and has great practical significance.

Electrochromism refers to the phenomenon that displayed by some materials of reversibly changing color under the action of an applied electric field. Electrochromic device only needs a small voltage (about 2V) to work, and the original color or fading state can be maintained in the open circuit, so the energy consumption is less.

The ethanol gas sensor can detect the ethanol content in drunk driving inspection or industrial production, So as to reduce or avoid traffic accidents or production safety accidents. In recent years, the development of ethanol sensors has become more extensive and in-depth, and the ethanol sensing characteristics of tungsten oxide have received extensive attention from researchers.