不同介质中Au纳米粒子二聚体SERS增强效应的理论模拟研究

Theoretical Simulation on SERS Effect of Au Nanoparticles Dimer in Different Medias

对贵金属纳米粒子结构表面等离激元的精准调控一直是表面增强拉曼光谱领域的热点,在众多影响SPR的因素中,介质环境一直被众多研究者忽视。本文利用理论模拟系统地研究了介质环境对于贵金属纳米结构SPR的影响,研究发现介质的介电常数增大,SPR的峰位置红移,在合适的激发线下,其所对应的SERS增强效应增大。改变介质的种类可实现SERS"热点"从纳米粒子-纳米粒子模式向纳米粒子-金属基底模式的有效转移。

The precise control on the surface plasma resonance(SPR)of noble metallic nanostructures has been attracted considerable attention in the field of surface enhanced Raman spectroscopy(SERS).Among the factors affecting SPR,involving the size,shape and composition,the media environment has always been neglected.Herein,the theoretical simulation was employed to investigate the effect of media conditions on the SPR of Au nanoparticles dimers.The results revealed that the frequencies of the SPR bands were red-shifted with the increase of the dielectric constant,the corresponding SERS effect was improved for a certain excitation line.By changing the media conditions,the'hot spots'was transferred successfully from the nanoparticle-nanoparticle mode to the gap mode.