Lafuente Marta, Kooijman Lucas J, Rodrigo Sergio G, Berenschot Erwin, Mallada Reyes, Pina María P, Tas Niels R, Tiggelaar Roald M
Departamento de Ingeniería Química y Tecnologías del Medio Ambiente, Campus Rio Ebro, C/Maria de Luna s/n, Universidad de Zaragoza, 50018 Zaragoza, Spain.
Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain.
Micromachines (Basel). 2024 Sep 4;15(9):1129. doi: 10.3390/mi15091129.
Surface enhanced Raman spectroscopy (SERS) is gaining importance as sensing tool. However, wide application of the SERS technique suffers mainly from limitations in terms of uniformity of the plasmonics structures and sensitivity for low concentrations of target analytes. In this work, we present SERS specimens based on periodic arrays of 3D-structures coated with silver, fabricated by silicon top-down micro and nanofabrication (10 mm × 10 mm footprint). Each 3D-structure is essentially an octahedron on top of a pyramid. The width of the top part-the octahedron-was varied from 0.7 µm to 5 µm. The smallest structures reached an analytical enhancement factor (AEF) of 3.9 × 10 with a relative standard deviation (RSD) below 20%. According to finite-difference time-domain (FDTD) simulations, the origin of this signal amplification lies in the strong localization of electromagnetic fields at the edges and surfaces of the octahedrons. Finally, the sensitivity of these SERS specimens was evaluated under close-to-reality conditions using a portable Raman spectrophotometer and monitoring of the three vibrational bands of 4-nitrobenzenethiol (4-NBT). Thus, this contribution deals with fabrication, characterization and simulation of multiscale 3D-structures with SERS activity.
表面增强拉曼光谱(SERS)作为一种传感工具正变得越来越重要。然而,SERS技术的广泛应用主要受到等离子体结构均匀性以及对低浓度目标分析物灵敏度方面的限制。在这项工作中,我们展示了基于涂有银的三维结构周期性阵列的SERS样本,这些样本是通过硅的自上而下的微纳加工制造的(占地面积为10毫米×10毫米)。每个三维结构本质上是一个位于金字塔顶部的八面体。顶部八面体部分的宽度从0.7微米变化到5微米。最小的结构达到了3.9×10的分析增强因子(AEF),相对标准偏差(RSD)低于20%。根据时域有限差分(FDTD)模拟,这种信号放大的起源在于八面体边缘和表面处电磁场的强烈局域化。最后,使用便携式拉曼分光光度计并监测4-硝基苯硫酚(4-NBT)的三个振动带,在接近实际的条件下评估了这些SERS样本的灵敏度。因此,本文涉及具有SERS活性的多尺度三维结构的制造、表征和模拟。