Department of Chemical Engineering, Queen's University, 19 Division St., Kingston, ON K7L 3N6, Canada.
Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, ON K7L 3N6, Canada.
Biosensors (Basel). 2022 Feb 17;12(2):128. doi: 10.3390/bios12020128.
Metallic nanoparticles (MNPs) and metallic nanostructures are both commonly used, independently, as SERS substrates due to their enhanced plasmonic activity. In this work, we introduce and investigate a hybrid nanostructure with strong SERS activity that benefits from the collective plasmonic response of the combination of MNPs and flow-through nanohole arrays (NHAs). The electric field distribution and electromagnetic enhancement factor of hybrid structures composed of silver NPs on both silver and gold NHAs are investigated via finite-difference time-domain (FDTD) analyses. This computational approach is used to find optimal spatial configurations of the nanoparticle positions relative to the nanoapertures and investigate the difference between Ag-NP-on-Ag-NHAs and Ag-NP-on-Au-NHAs hybrid structures. A maximum G value of 6.8 × 10 is achieved with the all-silver structure when the NP is located 0.5 nm away from the rim of the NHA, while the maximum of 4.7 × 10 is obtained when the nanoparticle is in full contact with the NHA for the gold-silver hybrid structure. These results demonstrate that the hybrid nanostructures enable hotspot formation with strong SERS activity and plasmonic enhancement compatible with SERS-based sensing applications.
金属纳米粒子（MNPs）和金属纳米结构都由于其增强的等离子体活性而被独立地用作 SERS 基底。在这项工作中，我们引入并研究了一种具有强 SERS 活性的混合纳米结构，它受益于 MNPs 和流动纳米孔阵列（NHA）组合的集体等离子体响应。通过有限差分时域（FDTD）分析研究了银 NPs 在银和金 NHA 上的混合结构的电场分布和电磁增强因子。这种计算方法用于找到相对于纳米孔的纳米粒子位置的最佳空间配置，并研究 Ag-NP-on-Ag-NHAs 和 Ag-NP-on-Au-NHAs 混合结构之间的差异。当 NP 距离 NHA 的边缘 0.5nm 时，全银结构可实现最大 G 值为 6.8×10，而当纳米粒子与金-银混合结构的 NHA 完全接触时，最大 G 值为 4.7×10。这些结果表明，混合纳米结构能够形成具有强 SERS 活性和等离子体增强的热点，与基于 SERS 的传感应用兼容。
