针尖增强拉曼光谱中物理与化学效应的实验研究  

Experimental Study of Electromagnetic and Chemical Enhancement in Tip-Enhanced Raman Spectroscopy

作　　者：苏亚荣[1,2] 时元振 侯宜栋 刘旭东[3] 杜惊雷 SU Yarong;SHI Yuanzhen;HOU Yidong;LIU Xudong;DU Jinglei(College of Physical Science and Technology,Sichuan University,Chengdu 610064,China;Sino-British Joint Materials Research Institute,Chengdu 610064,China;College of Chemistry,Sichuan University,Chengdu 610064,China)

机构地区：[1]四川大学物理科学与技术学院,成都610064 [2]中英联合材料研究所,成都610064 [3]四川大学化学学院,成都610064

出　　处：《光散射学报》2018年第4期337-343,共7页The Journal of Light Scattering

摘　　要：针尖增强拉曼光谱(Tip-Enhanced Raman Spectroscopy,TERS)的增强机制中物理和化学效应的影响是一个非常重要的研究课题。通过采用基于原子力显微镜平台的针尖增强拉曼光谱系统,深入研究了金纳米光栅表面苯硫酚的针尖增强拉曼效应。通过与相同样品在表面增强拉曼光谱系统中不同模式的增强因子对比,发现在TERS中物理效应和化学效应对其拉曼信号的增强均有贡献,同时TERS技术会带来更大的化学增强效应,尽管在针尖加载的过程中并未改变苯硫酚与金光栅基底之间的化学环境。这种现象可以归因于苯硫酚分子在垂直金属表面方向上的各向异性及其与针尖表面电荷和外加光电场之间相互作用的影响。本文的研究促进人们对TERS机理的理解,为进一步完善TERS增强理论奠定基础。The distinction between physical and chemical enhancement effects is a very important research topic in tip-enhanced Raman spectroscopy.In this paper,we studied enhancement mechanism in tip-enhanced Raman spectroscopy(TERS)for benzenethiol adsorbed on the surface of gold nano-gratings based on an AFM-TERS system.It was found that both physical and chemical effects contributed in TERS enhancement.By comparing the enhancement factors corresponding to different modes in the SERS spectrum,the TERS technology brings greater chemical enhancement effects.This phenomenon can be attributed to the anisotropy of benzenethiol along with the vertical metal surface direction and the redistribution of the surface charge on metal tip under extra electric field.The research in this paper promotes people's understanding of the Raman enhancement mechanism and provides theoretical support for the further improvement of the TERS enhancement theory and also the design for high-quality SERS substrates.

关 键 词：针尖增强拉曼光谱 表面增强拉曼光谱 金属光栅 苯硫酚 

分 类 号：O433[机械工程—光学工程]