Determining molecular orientation via single molecule SERS in a plasmonic nano-gap.
Determining molecular orientation via single molecule SERS in a plasmonic nano-gap.
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DOI：
10.1039/c7nr05107g
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发表时间：
2017-11
期刊：
影响因子：
6.7
通讯作者：
Addison R. L. Marshall;J. Stokes;F. N. Viscomi;J. Proctor;J. Gierschner;J. Bouillard;A. Adawi
中科院分区：
文献类型：
--
作者：
Addison R. L. Marshall;J. Stokes;F. N. Viscomi;J. Proctor;J. Gierschner;J. Bouillard;A. Adawi
在这项工作中，等离子体纳米间隙组成的银纳米粒子耦合到扩展的银膜已被充分优化的单分子表面增强拉曼散射（Sers）光谱。Sers信号被发现是强烈依赖于颗粒的大小和相对于纳米间隙内的场的分子取向。使用时域有限差分（FDTD）模拟，以补充实验测量，激发增强和发射增强的系统作为粒子尺寸的函数之间的复杂的相互作用被强调。此外，结合密度泛函理论（DFT），在纳米间隙中定义良好的场方向能够恢复单个分子的取向。
In this work, plasmonic nano-gaps consisting of a silver nanoparticle coupled to an extended silver film have been fully optimized for single molecule Surface-Enhanced Raman Scattering (SERS) spectroscopy. The SERS signal was found to be strongly dependent on the particle size and the molecule orientation with respect to the field inside the nano-gap. Using Finite Difference Time Domain (FDTD) simulations to complement the experimental measurements, the complex interplay between the excitation enhancement and the emission enhancement of the system as a function of particle size were highlighted. Additionally, in conjunction with Density Functional Theory (DFT), the well-defined field direction in the nano-gap enables to recover the orientation of individual molecules.