纳米Ag材料表面等离子体激元引起的表面增强拉曼散射光谱研究

Research of surface enhanced Raman scattering caused by surface plasmon of Ag nano-structures

用热蒸发的方法制备了纳米Ag材料,并用扫描电子显微镜对纳米粒子进行了形貌的表征,通过紫外—可见分光光度计得到Ag纳米粒子的透过谱,得到了Ag纳米粒子的表面等离子体共振的峰值位置.以罗丹明6G为探针分子测定Ag纳米粒子衬底的表面增强拉曼散射效应,通过拉曼散射光谱与透过谱研究了由表面等离子体激元的强极化场引起的表面增强拉曼散射效应,结合透过谱与拉曼增益因子提出了一种描述表面等离子体光学和电学特性的方法,并结合扫描电镜的结果给出了不同结构的纳米Ag材料对表面等离子体激元强度的影响.

Silver nano-structures were synthesized through thermal evaporation. Scanning electron microscopy （SEM） observations showed that the silver nano-structures had several types of morphology. The optical properties of silver nano-structures were obtained by ultraviolet-visible spectrometry,which shows the resonance wavelength of surface plasmon. In this work,we demonstrate the surface enhanced Raman scattering （SERS） signals which allow us to track down the surface plasmon local field spectra of Ag nano-structures. To prove it,we also used rhodamine 6G deposited on samples. As a result,we show that the transmittance spectra and SERS enhancement gives a complete description of optical and electric field caused by surface plasmon resonance of Ag nano-structures. The difference of Raman enhancement also indicates that different structures give different surface plasmon intensity when combined with the result of SEM.