Michieli Niccolò, Balasa Ionut Gabriel, Kalinic Boris, Cesca Tiziana, Mattei Giovanni
Department of Physics and Astronomy, NanoStructures Group, University of Padova Via Marzolo 8 I-35131 Padova Italy
Nanoscale Adv. 2020 Jun 3;2(8):3304-3315. doi: 10.1039/d0na00208a. eCollection 2020 Aug 11.
Combining finite elements method electrodynamic simulations and cost-effective and scalable nanofabrication techniques, we carried out a systematic investigation and optimization of the sensing properties of non-interacting gold nanodisk arrays. Such plasmonic nanoarchitectures offer a very effective platform for fast and simple, label-free, optical bio- and chemical-sensing. We varied their main geometrical parameters (diameter and height) to monitor the plasmonic resonance position and to find the configurations that maximize the sensitivity to small layers of an analyte (local sensitivity) or to the variation of the refractive index of an embedding medium (bulk sensitivity). The spectral position of the plasmonic resonance can be tuned over a wide range from the visible to the near-IR region (500-1300 nm) and state-of-the-art performances can be obtained using the optimized nanodisks; we obtained local and bulk sensitivities of = 11.9 RIU and = 662 nm RIU, respectively. Moreover, the results of the simulations are compared with the performances of experimentally synthesized non-interacting Au nanodisk arrays fabricated by combining sparse colloidal lithography and hollow mask lithography, with the parameters obtained by the sensitivity numerical optimization. An excellent agreement between the experimental and the simulated results is demonstrated, confirming that the optimization performed with the simulations is directly applicable to nanosensors realized with cost-effective methods, due to the quite large stability basin around the maximum sensitivities.
结合有限元法电动力学模拟以及经济高效且可扩展的纳米制造技术，我们对非相互作用金纳米盘阵列的传感特性进行了系统研究和优化。这种等离子体纳米结构为快速、简单、无标记的光学生物和化学传感提供了一个非常有效的平台。我们改变了它们的主要几何参数（直径和高度），以监测等离子体共振位置，并找到对分析物小层（局部灵敏度）或嵌入介质折射率变化（体灵敏度）灵敏度最大化的配置。等离子体共振的光谱位置可以在从可见光到近红外区域（500 - 1300 nm）的宽范围内进行调谐，并且使用优化后的纳米盘可以获得最先进的性能；我们分别获得了局部灵敏度为 = 11.9 RIU 和体灵敏度为 = 662 nm RIU。此外，将模拟结果与通过结合稀疏胶体光刻和空心掩膜光刻实验合成的非相互作用金纳米盘阵列的性能进行了比较，并与通过灵敏度数值优化获得的参数进行了对比。实验结果与模拟结果之间显示出极好的一致性，证实了通过模拟进行的优化可直接应用于采用经济高效方法实现的纳米传感器，这是由于在最大灵敏度附近存在相当大的稳定性区域。
