Self-Assembled Large Au Nanoparticle Arrays with Regular Hot Spots for SERS
Self-Assembled Large Au Nanoparticle Arrays with Regular Hot Spots for SERS
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DOI：
10.1002/smll.201100686
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发表时间：
2011-08-22
期刊：
影响因子：
13.3
通讯作者：
Vlasko-Vlasov, Vitalii K.
中科院分区：
文献类型：
--
作者：
Chen, Aiqing;DePrince, A. Eugene, III;Vlasko-Vlasov, Vitalii K.
80 nm的Au纳米粒子（NPs）的成本有效的自组装成大域，六方密排阵列的高灵敏度和高保真度的表面增强拉曼光谱（Sers）的证明。这些阵列表现出特定的光共振，由于强粒子间耦合，这是很好地再现时域有限差分（FDTD）模拟。NP之间的间隙形成热点的规则晶格，其使得能够对光致发光和拉曼信号两者进行大的放大。在较小的波长下，热点远离最小间隙位置延伸，这允许不适合小间隙的较大分析物的Sers。使用CdSe量子点（QD）的3-5倍以上的光致发光增强比以前报道的实验证明，并通过直接扫描电子显微镜成像的量子点负责的拉曼信号获得的电磁Sers增强因子的一个明确的估计约为10（4）。对于穿透NP带隙的苯乙撑分子，在较大波长处获得了约10（8）的更强增强。
The cost-effective self-assembly of 80 nm Au nanoparticles (NPs) into large-domain, hexagonally close-packed arrays for high-sensitivity and high-fidelity surface-enhanced Raman spectroscopy (SERS) is demonstrated. These arrays exhibit specific optical resonances due to strong interparticle coupling, which are well reproduced by finite-difference time-domain (FDTD) simulations. The gaps between NPs form a regular lattice of hot spots that enable a large amplification of both photoluminescence and Raman signals. At smaller wavelengths the hot spots are extended away from the minimum-gap positions, which allows SERS of larger analytes that do not fit into small gaps. Using CdSe quantum dots (QDs) a 3-5 times larger photoluminescence enhancement than previously reported is experimentally demonstrated and an unambiguous estimate of the electromagnetic SERS enhancement factor of approximate to 10(4) is obtained by direct scanning electron microscopy imaging of QDs responsible for the Raman signal. Much stronger enhancement of approximate to 10(8) is obtained at larger wavelengths for benzenethiol molecules penetrating the NP gaps.