Departamento de Quimica Inorganica, Facultad de Quimica, Pontificia Universidad Católica de Chile, Chile.
Appl Spectrosc. 2011 Aug;65(8):838-43. doi: 10.1366/11-06279.
Coated silver (Ag) colloids synthesized with D-glucose permit the observation of surface-enhanced fluorescence (SEF) and surface-enhanced resonance Raman scattering (SERRS) of the rhodamine B (RhB) molecule. The organic coating formed during the synthesis of the Ag nanostructures was identified by its surface-enhanced Raman scattering (SERS) spectrum as D-gluconic acid. The RhB molecule is used to exemplify the distance dependence of SEF and SERRS on the coated Ag nanostructures. The fluorescence enhancement factor for RhB on D-gluconic acid coated silver nanoparticles was determined experimentally and estimated using a simple model. Further support for the plasmon enhancement is obtained from the fact that the measured fluorescence lifetime of RhB on the silver coated with D-gluconic acid is shorter than that found on a glass surface. A very modest enhancement factor is obtained, as expected for very short distance between RhB and the metal surface. Given the very thin metal-fluorophore separation, estimated from the size of the D-gluconic acid, the energy transfer or fluorescence quenching is still efficient and the SEF enhancement is just overcoming the energy transfer. Therefore, both SEF and SERRS are observed. Notably, the aggregation of coated nanoparticles also increases the enhancement factor for SEF.
用 D-葡萄糖合成的包覆银（Ag）胶体允许观察到罗丹明 B（RhB）分子的表面增强荧光（SEF）和表面增强共振拉曼散射（SERRS）。在 Ag 纳米结构合成过程中形成的有机涂层通过其表面增强拉曼散射（SERS）光谱被鉴定为 D-葡萄糖酸。RhB 分子被用来举例说明 SEF 和 SERRS 对包覆 Ag 纳米结构的距离依赖性。通过实验确定了 RhB 在 D-葡萄糖酸包覆的银纳米粒子上的荧光增强因子，并使用简单模型进行了估计。从 RhB 在涂有 D-葡萄糖酸的银上的测量荧光寿命短于在玻璃表面上的测量荧光寿命这一事实，可以进一步证明等离子体增强。考虑到 RhB 与金属表面之间的距离非常短，预计会得到非常适度的增强因子。鉴于从 D-葡萄糖酸的大小估计的非常薄的金属荧光团分离，能量转移或荧光猝灭仍然有效，并且 SEF 增强只是克服了能量转移。因此，既观察到 SEF 又观察到 SERRS。值得注意的是，包覆纳米粒子的聚集也会增加 SEF 的增强因子。
