在石墨烯-Ag纳米颗粒复合结构表面增强拉曼散射(SERS)基底常规制备工艺的基础上, 提出了采用偶联剂吸附的方法来改善Ag纳米颗粒在目标基底上分布的均匀性; 采用双层聚甲基丙烯酸甲酯(PMMA)来转移石墨烯, 以减少石墨烯表面的缺陷; 采用退火处理的方法来降低SERS基底的拉曼背景噪声, 从而提高拉曼光谱的对比度。 实验结果表明, 采用优化制备工艺得到的复合结构SERS基底均匀性有较大提高, 石墨烯G峰和2D峰的增强拉曼光谱对比度分别提高了54.9%和64.3%, 罗丹明6G(R6G)分子在774和1 363 cm-1处的拉曼光谱强度随浓度变化关系的拟合优度(R2)分别达到了0.997 5和0.986 7。

Based on general preparation process of surface-enhanced Raman scattering (SERS) substrate of graphene-silver nanoparticles composites, the coupling agent has been used to improve the uniformity of silver nanoparticles adsorbed on the target substrates; bilayer of polymethylmethacrylate (PMMA) has been used to transfer graphene in order to reduce the defects of graphene; annealing treatment has been used to reduce the Raman background noise and improve the contrast of Raman spectra. The experimental results indicate that using the optimized preparation process can improve the uniformity of SERS substrate. The contrast of graphene Raman signal at G and 2D peak increased by 54.9% and 64.3%, respectively. The goodness of fit (R2) on the relationship between Raman intensities of Rhodamine 6G (R6G, at 774 and 1 363 cm-1) and concentration achieved 0.997 5 and 0.986 7, respectively.