Stacked and Tunable Large-Scale Plasmonic Nanoparticle Arrays for Surface-Enhanced Raman Spectroscopy
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- 作者：Stefan M眉hlig ; Dana Cialla ; Alastair Cunningham ; Anne M盲rz ; Karina Weber ; Thomas B眉rgi ; Falk Lederer ; Carsten Rockstuhl
- 刊名：Journal of Physical Chemistry C
- 出版年：2014
- 出版时间：May 15, 2014
- 年：2014
- 卷：118
- 期：19
- 页码：10230-10237
- 全文大小：446K
- 年卷期：v.118,no.19(May 15, 2014)
- ISSN：1932-7455
文摘
Surface-enhanced Raman spectroscopy takes advantage of plasmonic substrates that sustain resonances at tunable frequencies with a reproducibly extraordinary field enhancement. Low-cost and large-scale fabrication of these substrates is further required. Here, we present stacked large-scale arrays of strongly coupled gold nanoparticles as promising candidates for such substrates. These arrays are fabricated by bottom-up techniques that fulfill the aforementioned requirements. The distance between adjacent arrays in the stack is controlled with high precision using a discrete number of monolayers of molecules that enable the spectral position of the plasmonic resonances to be tuned. Although the nanoparticles are randomly arranged in each array, the spatial proximity of the stacked arrays enables a strong coupling among nanoparticles to be achieved in adjacent arrays. The huge field enhancements due to these strongly coupled gold nanoparticles are shown to enhance the Raman signal. We show that effectively the optical response from these stacked arrays and the Raman signals can be understood in a simplifying picture where only an individual nanoparticle dimer is considered. The possibility to tune the plasmonic resonances of the substrate across the visible spectrum makes our material a plasmonic substrate of choice for many applications where light鈥搈atter interactions need to be intensified.