Mildly reduced graphene oxide-Ag nanoparticle hybrid films for surface-enhanced Raman scattering.
Mildly reduced graphene oxide-Ag nanoparticle hybrid films for surface-enhanced Raman scattering.
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DOI：
10.1186/1556-276x-7-205
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发表时间：
2012-04-03
影响因子：
--
通讯作者：
Liang K
中科院分区：
文献类型：
--
作者：
Li X;Tay BK;Li J;Tan D;Tan CW;Liang K
通过酰胺化反应在SiO2/Si表面自组装大面积温和还原氧化石墨烯（MR-GO）单层膜。以MR-GO为模板，采用柠檬酸钠为还原剂，在紫外光照射下，将MR-GO单分子层浸入银盐溶液中，制备了MR-GO-Ag纳米粒子（MR-GO-Ag NP）杂化薄膜。SEM图像表明具有小颗粒间间隙的Ag纳米颗粒均匀地分布在MR-GO单层上。拉曼光谱表明，银纳米颗粒下方的MR-GO单层可以有效地淬灭在激光激发下从银膜和染料分子发射的荧光信号，导致化学增强（CM）。具有窄禁带的Ag纳米颗粒提供了许多热点，这些热点与电磁机制（EM）密切相关，并且被认为显著增强了分子的拉曼信号。由于CM和EM效应的共同贡献以及MR-GO和Ag NP之间的配位机制，MR-GO-Ag NP混合膜比单独的Ag膜或MR-GO单层表现出更优异的拉曼信号增强性能。这将进一步丰富表面增强拉曼散射在分子检测中的应用。
Large-area mildly reduced graphene oxide (MR-GO) monolayer films were self-assembled on SiO2/Si surfaces via an amidation reaction strategy. With the MR-GO as templates, MR-GO-Ag nanoparticle (MR-GO-Ag NP) hybrid films were synthesized by immersing the MR-GO monolayer into a silver salt solution with sodium citrate as a reducing agent under UV illumination. SEM image indicated that Ag NPs with small interparticle gap are uniformly distributed on the MR-GO monolayer. Raman spectra demonstrated that the MR-GO monolayer beneath the Ag NPs can effectively quench the fluorescence signal emitted from the Ag films and dye molecules under laser excitation, resulting in a chemical enhancement (CM). The Ag NPs with narrow gap provided numerous hot spots, which are closely related with electromagnetic mechanism (EM), and were believed to remarkably enhance the Raman signal of the molecules. Due to the co-contribution of the CM and EM effects as well as the coordination mechanism between the MR-GO and Ag NPs, the MR-GO-Ag NP hybrid films showed more excellent Raman signal enhancement performance than that of either Ag films or MR-GO monolayer alone. This will further enrich the application of surface-enhanced Raman scattering in molecule detection.