Au@SiO_(2)核-壳层单晶八面体纳米棒光吸收性质的研究

The Research on Optical Absorption Properties of Au@SiO_(2) Core-Shell Single Crystal Octahedron Nanorod

包覆材料改变了单一材料的力学、光学性质。利用离散偶极近似(Discrete Dipole Approximation,简称DDA)的方法,系统研究二氧化硅壳层、尺寸及形貌等因素对Au@SiO_(2)核-壳层单晶八面体纳米棒光学吸收谱峰值、峰位及其近场分布的影响。研究表明SiO_(2)壳层包覆的Au纳米棒的光学吸收谱同样表现为横向和纵向吸收峰。随着SiO_(2)壳层厚度增加,Au@SiO_(2)核-壳层单晶八面体纳米棒横向和纵向吸收缝的强度明显减弱,横向吸收峰的位置发生微小的蓝移,而纵向吸收峰位发生明显的红移。SiO_(2)壳层在提高纳米棒硬度的同时,改变光学吸收峰的峰值和峰位,削弱了Au核表面等离子体共振强度(Surface Plasma Resonance-SPR)。

The coating material changes the mechanical and optical properties of a single material.Using the Discrete Dipole Approximation(DDA)method,the influence of SiO_(2) shell material,size and morphology on peak value,peak location and near-field distribution of optical absorption spectrum of Au@SiO_(2) core-shell single crystal octahedron nanorod is systematically studied.The results show that the optical absorption spectrum of Au nanorod coated with SiO_(2) shell also shows transverse and longitudinal absorption peak.With the increase of SiO_(2) shell thickness,the intensity of the Au@SiO_(2) core-shell single crystal octahedron nanorod’s transverse and longitudinal absorption peak decreases significantly,the position of the transverse absorption peak is slightly blue shifted,however the longitudinal absorption peak location is significantly red shifted.The SiO_(2) shell can improve the hardness of the nanorod and change the peak value and position of optical absorption peak,which weakens the surface plasmon resonance intensity of Au core.