Velez Raymond A, Lavrik Nickolay V, Kravchenko Ivan I, Sepaniak Michael J, Jesus Marco A De
1 University of Puerto Rico, Department of Chemistry, Mayaguez, Puerto Rico, USA.
2 Oak Ridge National Laboratory, Center for Nanophase Materials Sciences, Oak Ridge, TN, USA.
Appl Spectrosc. 2019 Jun;73(6):665-677. doi: 10.1177/0003702819846503. Epub 2019 May 20.
The use of nanomachining methods capable of reproducible construction of nano-arrayed devices have revolutionized the field of plasmonic sensing by the introduction of a diversity of rationally engineered designs. Significant strides have been made to fabricate plasmonic platforms with tailored interparticle gaps to improve their performance for surface-enhanced Raman scattering (SERS) applications. Over time, a dichotomy has emerged in the implementation of SERS for analytical applications, the construction of substrates, optimization of interparticle spacing as a means to optimize electromagnetic field enhancement at the localized surface plasmon level, and the substrate sensitivity over extended areas to achieve quantitative performance. This work assessed the enhancement factor of plasmonic Ag/SiO/Si disc-on-pillar (DOP) arrays of variable pitch with its analytical performance for quantitative applications. Experimental data were compared with those from finite-difference time-domain (FDTD) simulations used in the optimization of the array dimensions. A self-assembled monolayer (SAM) of benzenethiol rendered highly reproducible signals (RSD ∼4-10%) and SERS substrate enhancement factor (SSEF) values in the orders of 10-10 for all pitches. Spectra corresponding to rhodamine 6G (R6G) and 4-aminobenzoic acid demonstrated the advantages of using the more densely packed DOP arrays with a 160 nm pitch (gap = 40 nm) for quantitation in spite of the strongest SSEF was attained for a pitch of 520 nm corresponding to a 400 nm gap.
能够可重复构建纳米阵列器件的纳米加工方法的应用，通过引入多种合理设计的结构，彻底改变了等离子体传感领域。在制造具有定制颗粒间间隙的等离子体平台以提高其在表面增强拉曼散射（SERS）应用中的性能方面已经取得了重大进展。随着时间的推移，在SERS用于分析应用的实施、基底的构建、作为在局部表面等离子体水平优化电磁场增强手段的颗粒间距优化以及在扩展区域实现定量性能的基底灵敏度方面出现了分歧。这项工作评估了可变间距的等离子体Ag/SiO/Si柱上圆盘（DOP）阵列的增强因子及其在定量应用中的分析性能。将实验数据与用于优化阵列尺寸的有限差分时域（FDTD）模拟数据进行了比较。苯硫醇的自组装单层（SAM）对于所有间距都产生了高度可重复的信号（相对标准偏差约为4 - 10%）以及10 - 10数量级的SERS基底增强因子（SSEF）值。对应于罗丹明6G（R6G）和4 - 氨基苯甲酸的光谱表明，尽管对于间距为520 nm（间隙 = 400 nm）时获得了最强的SSEF，但使用间距为160 nm（间隙 = 40 nm）的更密集排列的DOP阵列进行定量分析具有优势。
