Cadmium sulfide nanocrystals are the most widely studied and the most promising class of II-VI semiconductor nanocrystals. Due to their important nonlinear optical properties, luminescent properties and other physical and chemical properties, they have attracted worldwide attention. As a very important semiconductor material, it has been widely used in many fields, such as various light-emitting devices, laser and infrared detection devices, infrared windows and nonlinear optical materials and photosensitive sensors. Especially cadmium sulfide can absorb visible light very well, so it is the first choice material of photocatalyst.

Nano materials show a series of unique properties in micro scale, such as surface effect, quantum effect, small size effect, quantum tunneling effect and so on. Under the influence of these properties, nano materials, especially one-dimensional nano materials, show outstanding specific surface area, adsorption and desorption performance, which contributes to the development of one-dimensional materials.

In order to obtain a gas sensitive detector with high selectivity, high sensitivity, low working temperature and high stability, gas sensitive properties are mainly improved by modifying gas sensitive materials Tungsten oxide with one-dimensional nanowire structure attracts many researchers because of its huge specific surface area. In the aspect of gas sensing material modification, the main ways are doping noble metal Pt, Au, PD or transition metal oxide, in addition, it can be modified by constructing heterostructure. Compared with the two, the cost of heterostructure modification is relatively low.

Tungsten oxide film has important application value in display field because of its excellent electrochromic characteristics. It can effectively improve its electrochromic performance by doping a proper amount of FTO (fluorine doped tin oxide) nanocrystals. The display device prepared by the film has the characteristics of no blind angle, high contrast, low energy consumption, and can be used as electronic paper, indicator board, etc.