Explanation

Also known as colloidal nanocrystals, it refers to the inorganic particles that grow in solution, have a particle size of nanometer, and are stabilized by a layer of surfactant attached to the surface, which can be single crystal, polycrystal or quasicrystal, as opposed to bulk materials. Sometimes called "artificial atoms. Their electronic state density (the fundamental point of many physical property regulation) It is easy to adjust the composition, size and shape of nanocrystal. nanocrystal has typical size effect, surface effect and quantum confinemem effect of nanomaterials. Semiconductor nano crystal whose size is less than 100nm are also called quantum dots. Chemists can control the composition, size, shape, crystal structure and surface properties of nano crystal to achieve more precise control of physical and chemical properties of these materials. The synthetic elements of colloidal nanocrystals include precursors, organic surfactants and solvents. In the growth process, the widely recognized growth mechanisms include Ostwald growth, LaMer growth, and orientation epiphyte. The two key steps of "rapid nucleation" and "slow growth" in the LaMer growth mechanism can be used to realize the preparation of monodisperse nanocrystal. Different surfactants can be used to achieve isotropic and anisotropic growth restriction, thereby achieving precise regulation of their size and shape. In particular, it is possible to selectively restrict the growth of some crystal faces by using the bonding force between the active groups of surfactants and different crystal faces, so as to achieve crystal particles with different shapes and different crystal faces. Therefore, by regulating the exposure of highly active crystal surfaces, it has shown broad application prospects in the field of catalysis. At present, the widely studied nanocrystal include metals, metal oxides, semiconductor nanocrystal and heterogeneous nanocrystal. These nanocrystal show broad application prospects in luminescence, photoelectric information, new energy, biology, catalysis and other fields.

Classification