Lee En-Tzu, Cheng Hui-Wen, Yang Jung-Yen, Li Yiming
J Nanosci Nanotechnol. 2017 Feb;17(2):871-77. doi: 10.1166/jnn.2017.12660.
The metal nanoparticles exhibit different degrees of localized surface plasmon resonance which depends on different type nano-sized structures. In this work, in experiment, Au/TiO2/Ti/Si SERS-active substrate with spherical shape nanoparticles is fabricated by using a hydrothermal treatment process and applied to detect Rhodamine 6G sample. Based on experimental observation, a three-dimensional finite-difference time-domain simulation is utilized to explore the local field distributions. We examine the effect of surface roughness and shape of Au nanoparticles on the enhancement magnitude of local electric field of SERS-active substrates. Besides, different shapes of nanoparticles, nanocages and Au/Ag alloy nanoparticles are also modeled and discussed. The engineering findings of this study indicate that the substrate with roughened surface may exhibit large electric field enhancement; in particular, for the cubic shape of nanoparticles. The electric field enhancement of spherical and cubic nanoparticles could be further enlarged by Au/Ag alloy and Au nanocage structures. The results may benefit the design and fabrication of nanoparticles for various biochemical sensing applications.
金属纳米颗粒表现出不同程度的局域表面等离子体共振，这取决于不同类型的纳米尺寸结构。在本工作中，实验上通过水热法制备了具有球形纳米颗粒的Au/TiO2/Ti/Si表面增强拉曼散射（SERS）活性基底，并将其应用于检测罗丹明6G样品。基于实验观察，利用三维时域有限差分模拟来探究局部场分布。我们研究了金纳米颗粒的表面粗糙度和形状对SERS活性基底局部电场增强幅度的影响。此外，还对不同形状的纳米颗粒、纳米笼和金/银合金纳米颗粒进行了建模和讨论。本研究的工程学发现表明，表面粗糙的基底可能表现出较大的电场增强；特别是对于立方体形的纳米颗粒。金/银合金和金纳米笼结构可以进一步放大球形和立方体形纳米颗粒的电场增强。这些结果可能有助于设计和制造用于各种生化传感应用的纳米颗粒。
