Surface-enhanced Raman spectroscopy of self-assembled monolayers: Sandwich architecture and nanoparticle shape dependence
Surface-enhanced Raman spectroscopy of self-assembled monolayers: Sandwich architecture and nanoparticle shape dependence
复制标题
DOI：
10.1021/ac048176x
复制
发表时间：
2005-05-15
影响因子：
7.4
通讯作者：
Murphy, CJ
中科院分区：
文献类型：
--
作者：
Orendorff, CJ;Gole, A;Murphy, CJ
本文研究了静电固定不同形状金纳米粒子的4-巯基苯甲酸（4-MBA）自组装单层（SAMs）的表面增强拉曼散射（SERS）光谱。与溶液中的4-MBA相比，在固定金纳米晶体的存在下，4-MBA的SERS光谱增强了10(7)-10(9)倍。大的增强因子可能是纳米颗粒（局部表面等离子体激元）和光滑的金衬底（表面等离子体激元）之间的等离子体耦合的结果，在它们的界面上产生了大的局部电磁场，4-MBA分子位于这个夹层结构中。此外，增强因子取决于纳米颗粒的形状，并以10倍的倍数变化。这种SERS几何结构为吸附在平面基底上的分子提供了较大的表面增强，对于确定二维基底上检测的低拉曼散射体的化学信息非常有用。
Surface enhanced Raman scattering (SERS) spectra of 4-mercaptobenzoic acid (4-MBA) self-assembled monolayers (SAMs) on gold substrates is presented for SAMs onto which gold nanoparticles of various shapes have been electrostatically immobilized. SERS spectra of 4-MBA SAMs are enhanced in the presence of immobilized gold nanocrystals by a factor of 10(7)-10(9) relative to 4-MBA in solution. Large enhancement factors are a likely result of plasmon coupling between the nanoparticles (localized surface plasmon) and the smooth gold substrate (surface plasmon polariton), creating large localized electromagnetic fields at their interface, where 4-MBA molecules reside in this sandwich architecture. Moreover, enhancement factors depend on nanoparticle shape and vary by a factor of 10(2). This SERS geometry offers large surface enhancements for molecules adsorbed onto planar substrates and could be quite useful for determining chemical information for poor Raman scatterers from assays on 2-D substrates.