A DDA Calculation on the Optical Properties of Silver Nanorods
- Received Date: 2003-11-27
- Discrete dipole approximation，Nanorods，Nanosphere，Optical properties，Silver /
Abstract: The optical properties of metal nanoparticles are quite different from those of the bulk materials mainly due to the collective oscillations of their conduction electrons known as the surface plasmon resonance（SPR），which is strongly dependent on the particle shape and size，and the dielectric properties of the local environment where the nanoparticles are embedded in. Based on the discrete dipole approximation（DDA）method，we studied the optical properties of silver nanorods with different aspect ratios in some special dielectric environment including air，water，acetone，methylene chloride and pyridine. The DDA simulation of the ultraviolet-visible（UV-Vis）extinction spectra of silver nanorods with varying aspect ratios shows the plasmons absorption splits into two bands corresponding to the oscillation of the free electrons along and perpendicular to the long axis of the rods. The transverse mode shows almost a fixed resonance at about 350 nm while the resonance of the longitudinal mode is red-shifted and strongly depends on the aspect ratio of the nanorods. An empirical formula was given to predict the peak position of the longitudinal palsmon band of the silver nanorods with different aspect ratios in the air. The calculation result also shows the maximum of the longitudinal plasmon band of a silver nanorod with a fixed aspect ratio depends on the medium dielectric constant in a linear way. The TEM image and corresponding UV-Vis extinction spectrum of silver nanosphere and nanorods synthesized by our lab are in good agreement with the DDA simulation results.
|Citation:||Yang Zhilin, Hu Jianqiang, Li Xiuyan, Zhou Haiguang, Tian Zhongqun. A DDA Calculation on the Optical Properties of Silver Nanorods[J]. Chinese Journal of Chemical Physics , 2004, 17(3): 253-258. doi: 10.1088/1674-0068/17/3/253-258|