PS微球阵列的制备与表面增强拉曼散射研究

摘要

为了研究不同直径PS微球(表面溅射Ag膜)基底的表面增强拉曼散射(SERS)效应,制造了一个新的表面增强拉曼散射(SERS)基底。通过在n型(100)单晶硅片上采用旋涂的方法,得到不同直径的呈六角形有序排列的单层PS微球阵列,然后在PS微球阵列表面磁控溅射一层约30 nm的Ag膜。利用拉曼光谱仪以罗丹明 R6 G为探针进行了SERS光谱测定,分析比较了不同直径PS微球阵列的表面增强拉曼散射效应,结果表明,溅射有 Ag膜的PS微球基底在不同直径下均有不同程度的 SERS效应。随着微球直径的增加,PS微球阵列的起伏程度不断加强(粗糙度不断增加),SERS 信号逐渐增强,当球直径达到600 nm 时,峰的增强信号达到最大,进而获得了一个最优化的SERS基底。同时发现在基底上获得了高信噪比的R6 G的SERS光谱,与苯环相关的一系列 C—C 双键伸缩振动特征谱以及与苯环相关的面内、面外变形振动特征谱均获得了明显增强。这种单一的大区域的拉曼散射基底,呈现出高低相间起伏分布的微观形貌,不同 PS微球之间的空隙和深度有很明显的不同,能够显著改善表面 Ag膜颗粒的大小和分布,进而提高了 PS微球基底的SERS活性。该基底所具有的特殊阵列结构使其在利用 SERS探究化学和生物等领域的单分子结构有很大的应用潜力。%To research surface-enhanced Raman scattering effect of different diameters’polystyrene nanospheres (Ag-coated) substrates,we had prepared a new surface-enhanced Raman scattering substrate.It was prepared by using spin-coating and self-assembled to form monolayer and hexagonal close-packed (HCP)order colloidal-crystal films with PS nanospheres of different diameters.Then,a 30 nm Ag film was deposited on the PS arrays with magnetron sputtering.We detected Raman scattered spectrum by means of Roman spectroscopy instrument with Rhodamine R6G as a probe molecule,and the conclusion was drawn that all the substrates of Ag-coated PS nanospheres displayed stronger Raman enhancement.With the increase of the diameter of the microspheres,the degree of fluctuation of polystyrene nanospheres array was continuously strengthened (increasing rough-ness),and the SERS signal was enhanced gradually.The signal peak reached a maximum when the ball diameter was 600 nm, and then we aquired an optimal SERS substrate.Simultaneously,we found that the SERS spectra of R6G of a high signal to noise ratio was obtained on the substrate,and associated with the benzene ring within a range of C—C double bond stretching vibration characteristic spectrum and the inner surface and the outer surface deformation vibration characteristic spectra were sig-nificantly enhanced.The single and large-scale Raman scattering substrate presents especial nanostructure of high and low distri-bution.The depth and the gap between different PS microspheres show the obvious differences,which can significantly improve the surface morphology structure of Ag film and Raman scattering effect of PS nanospheres substrate.The substrate presenting special arrays’structure has significantly great potential in exploring molecule of chemical and biological filed.