Study On Extinction Characteristics Of Noble Metal Nanoparticles

In recent years due to the preeminent electro-optical properties, the noble metal nanoparticles have attracted much attention and become a hot topic in various fields. Its special effects such as quantum size effect, surface effect, quantum tunneling effect, etc. have been widely used in physics, chemistry, biology, communications and many other fields.Based on the FEM business software Comsol Multiphysics, the paper studies the extinction properties of spherical silver nanoparticles, ellipsoid silver nanoparticles, cylinder silver nanoparticles, gold and silver core-shell nanoparticles and the change of extinction peak with different size and dielectric environment.The results show that the extinction properties are influenced by size, component, permittivity, etc. For silver nanoparticles We can see one distinct extinction peak of spherical silver nanoparticles, two of ellipsoid silver nanoparticles and three of cylinder silver nanoparticles. With the increase of size parameter, the extinction peaks take place to a redshift and the scattering peak value increases gradually as the absorption peak value reduces.For gold and silver core-shell nanoparticles, with the increase of shell thickness, the extinction spectra of composite nanoparticles changes from two peaks as formed by two elemental metal to one peak with a wider half-peak width. With the increase of the permittivity of dielectric environment, the extinction peaks take place to a redshift.Then, we get the parabolic fitting relationship between extinction peak of spherical silver nanoparticles and the sphere diameter, and linear fitting relationship between extinction peak of other models and their size parameters. And we will get different extinction spectrum of noble metal nanoparticles by using the incident light which has different polarization direction.