Collective Plasmonic Properties in Few-Layer Gold Nanorod Supercrystals.
Collective Plasmonic Properties in Few-Layer Gold Nanorod Supercrystals.
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DOI：
10.1021/acsphotonics.5b00369
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发表时间：
2015-10-21
期刊：
影响因子：
7
通讯作者：
Liz-Marzán LM
中科院分区：
文献类型：
--
作者：
Hamon C;Novikov SM;Scarabelli L;Solís DM;Altantzis T;Bals S;Taboada JM;Obelleiro F;Liz-Marzán LM
金纳米棒超晶体已被广泛用于检测相关的生物分析物，检测限范围从纳米到皮摩尔的水平，证实了这些结构的生物传感的有前途的性质。即使超晶体的高度（即，堆叠的纳米棒层的数量）和增强因子，但没有系统的研究报道。为了解决这个问题，我们制备了不同层数的金纳米棒超晶体，并通过原子力显微镜、电子显微镜和表面增强拉曼散射对其进行了广泛的分析。将实验结果与对由数千个纳米棒构建块组成的真实尺寸的超晶体进行的数值模拟进行了比较。对模拟超晶体中的热点分布的分析表明，存在分布在不同深度的驻波，这取决于每个超晶体中的层数。在这些理论结果的基础上，我们解释了实验数据的分析物渗透到最顶层，这表明扩散到内部的超晶体将是至关重要的，如果要利用堆叠的纳米棒产生的完整的场增强。我们建议，我们的结论将是高度相关的下一代等离子体激元器件的设计。
Gold nanorod supercrystals have been widely employed for the detection of relevant bioanalytes with detection limits ranging from nano- to picomolar levels, confirming the promising nature of these structures for biosensing. Even though a relationship between the height of the supercrystal (i.e., the number of stacked nanorod layers) and the enhancement factor has been proposed, no systematic study has been reported. In order to tackle this problem, we prepared gold nanorod supercrystals with varying numbers of stacked layers and analyzed them extensively by atomic force microscopy, electron microscopy and surface enhanced Raman scattering. The experimental results were compared to numerical simulations performed on real-size supercrystals composed of thousands of nanorod building blocks. Analysis of the hot spot distribution in the simulated supercrystals showed the presence of standing waves that were distributed at different depths, depending on the number of layers in each supercrystal. On the basis of these theoretical results, we interpreted the experimental data in terms of analyte penetration into the topmost layer only, which indicates that diffusion to the interior of the supercrystals would be crucial if the complete field enhancement produced by the stacked nanorods is to be exploited. We propose that our conclusions will be of high relevance in the design of next generation plasmonic devices.