The Preparation Of Nanometer Silver Particle And Its Application

Substance is understood from the macroscopical and microscopical view. However, macroscopical matter is not connected with microscopical substance directly, and there is a mesoscopic, nanometer scale between them. Silver nano-particle has some particular properties, such as surface effect, quantum size effect, etc. Moreover, silver nano-particle can be utilized particularly, for surface enhanced Raman spectrum and medicine.In this dissertation, the preparation and application of the nanometer silver colloid are discussed. In the first place, three methods of preparing nanometer silver colloid are introduced, especially photochemical method. Secondly, the properties of nanometer silver colloid are studied in detail from the view of absorption spectrum. It is found that there is a critical point in the density of silver nitrate solution when the photochemical reaction of silver nitrate and trisodium citrate takes place. Above this point, the more the density of silver nitrate, the more the scale of silver particle. Below the point, the scale of silver particle decrease while the density of the solution is increased. Analyzing the absorption spectrum of silver colloid, it is discovered that trisodium citrate has two functions in the experiment. One is stabilization of silver colloid conglomeration, the other is deoxidization of silver nitrate or acting as an activator, In the end, the application of nanometer silver colloid is presented, including surface enhanced Raman scattering, self-assembly membrane of nanometer silver, and the application in atomic force microscopy.