Tungsten disulfide nanosheet is a typical transition metal sulfide. It is a black powder with a chemical formula of WS? and a molecular weight of 247.97. It has the characteristics of low friction coefficient, good thermochemical stability and photoelectric properties. It is widely used in lubricants, catalysts, energy storage electrode materials and other fields.
Tungsten disulfide nanosheet is a black-gray powder with a relative density of 7.51. In terms of solubility, it has only a weak solubility in cold water, but it can be dissolved in hot water; conventional hydrochloric acid and general alkali solution cannot dissolve it. Only a special solution mixed with concentrated nitric acid and hydrofluoric acid can make it dissolve. It has reducing properties and will react chemically when it encounters hot concentrated sulfuric acid, nitric acid, aqua regia and other strong oxidizing substances.
Excellent lubricity: Tungsten disulfide nanosheet has a low friction coefficient, usually between 0.03-0.07. This is due to its unique layered crystal structure, where the layers are maintained by weak van der Waals forces, and interlayer slip is prone to occur under the action of external forces. Low friction properties make it excellent in the field of lubrication, which can effectively reduce the wear of mechanical parts and improve the operating efficiency and service life of equipment.
Excellent optical properties: Tungsten disulfide nanosheets have unique optical absorption and emission characteristics in the visible light to near-infrared light region. Due to the quantum confinement effect caused by its two-dimensional structure, the optical band gap of the nanosheet will change compared with the bulk WS?, showing a clear exciton absorption peak. Moreover, the single-layer WS? nanosheet has a high photoluminescence efficiency and can be used in optoelectronic devices such as light-emitting diodes and photodetectors.
Good electrical properties: Tungsten disulfide nanosheets are a semiconductor material with a suitable band gap, and its electrical properties can be regulated by changing the number of layers, doping, etc. Compared with traditional silicon-based materials, WS? nanosheets have higher carrier mobility and switching ratio in nanoelectronic devices, which can achieve lower power consumption and higher operating speed, and are expected to become the key material for the next generation of nanoelectronic devices.
High mechanical properties: Although tungsten disulfide nanosheets are very thin, they have excellent mechanical properties. It has a high Young's modulus and tensile strength, and can withstand large external forces without breaking or deforming. This high mechanical property makes WS2 nanosheets have broad application prospects in the fields of flexible electronic devices, composite materials, etc., and can provide good mechanical support for the devices while maintaining their excellent electrical and optical properties.
Large specific surface area: Tungsten disulfide nanosheets have a large specific surface area and can provide more active sites to interact with other substances. This feature makes WS2 nanosheets exhibit excellent performance in catalysis, sensors and other fields. For example, in catalytic reactions, more active sites can increase the reaction rate and selectivity; in sensors, they can fully contact with the detected substances and improve the sensitivity and response speed of the sensor.
Good chemical stability: Tungsten disulfide nanosheets have good stability under certain temperature and chemical environment, and can resist the erosion of most chemical substances. This chemical stability enables it to maintain its own structure and performance in various complex application environments and prolong its service life. However, under some strong oxidizing or reducing conditions, its chemical properties will also change to a certain extent, and this feature can be used to design specific chemical reactions or functional devices.
