Probing Localized Surface Plasmons of Trisoctahedral Gold Nanocrystals for Surface Enhanced Raman Scattering

Trisoctahedral (TOH) shaped Au nanocrystals (NCs) have emerged as a new class of metal nanoparticles (MNP) due to its superior catalystic and SERS activities caused by the presence of high density atomic steps and dangling bonds on their high index facets. We examine the radiative localized surface...

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Bibliographic Details
Published in:arXiv.org 2017-05
Main Authors: Maity, Achyut, Maiti, Arpan, Satpati, Biswarup, Patsha, Avinash, Dhara, Sandip, Chini, Tapas Kumar
Format: Article
Language:English
Subjects:
Aggregates
Cathodoluminescence
Chemical bonds
Density
Gold
Nanocrystals
Nanoparticles
Plasmons
Raman spectra
Rhodamine 6G
Silicon substrates
Spatial data
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Summary:Trisoctahedral (TOH) shaped Au nanocrystals (NCs) have emerged as a new class of metal nanoparticles (MNP) due to its superior catalystic and SERS activities caused by the presence of high density atomic steps and dangling bonds on their high index facets. We examine the radiative localized surface plasmon resonance (LSPR) modes of an isolated single TOH Au NC using cathodoluminescence (CL), with high resolution spatial information of the local density of optical states (LDOS) across the visible spectral range. Further we show pronounced enhancement factor in the Raman scattering by performing Raman spectroscopic measurements on Rhodamine 6G (R6G) covered TOH Au NPs aggregates on a Si substrate. We believe that the hot spots between two adjacent MNP surfaces (nanogaps) can be significantly stronger than single particle LSPRs. Such nanogaps hotspots may have crucial role on the substantial SERS enhancement observed in this report. Consequently, the present study indicates that MNPs aggregates are highly desirable than individual plasmonic nanoparticles for possible applications in SERS based biosensing.
ISSN:2331-8422
DOI:10.48550/arxiv.1705.04447