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Title: Precision synthesis : designing hot spots over hot spots via selective gold deposition on silver octahedra edges
Authors: Hegde, Ravi S.
Tjiu, Weng Weei
Cui, Yan
Ling, Xing Yi
Liu, Yejing
Pedireddy, Srikanth
Lee, Yih Hong
Keywords: DRNTU::Science::Physics
Issue Date: 2014
Source: Liu, Y., Pedireddy, S., Lee, Y. H., Hegde, R. S., Tjiu, W. W., Cui, Y., et al. (2014). Precision synthesis : designing hot spots over hot spots via selective gold deposition on silver octahedra edges. Small, 10(23), 4940-4950.
Series/Report no.: Small
Abstract: A major challenge in plasmonic hot spot fabrication is to efficiently increase the hot spot volumes on single metal nanoparticles to generate stronger signals in plasmon-enhanced applications. Here, the synthesis of designer nanoparticles, where plasmonic-active Au nanodots are selectively deposited onto the edge/tip hot spot regions of Ag nanoparticles, is demonstrated using a two-step seed-mediated precision synthesis approach. Such a “hot spots over hot spots” strategy leads to an efficient enhancement of the plasmonic hot spot volumes on single Ag nanoparticles. Through cathodoluminescence hyperspectral imaging of these selective edge gold-deposited Ag octahedron (SEGSO), the increase in the areas and emission intensities of hot spots on Ag octahedra are directly visualized after Au deposition. Single-particle surface-enhanced Raman scattering (SERS) measurements demonstrate 10-fold and 3-fold larger SERS enhancement factors of the SEGSO as compared to pure Ag octahedra and non-selective gold-deposited Ag octahedra (NSEGSO), respectively. The experimental results corroborate well with theoretical simulations, where the local electromagnetic field enhancement of our SEGSO particles is 15-fold and 1.3-fold stronger than pure Ag octahedra and facet-deposited particles, respectively. The growth mechanisms of such designer nanoparticles are also discussed together with a demonstration of the versatility of this synthetic protocol.
ISSN: 1613-6810
DOI: 10.1002/smll.201401242
Rights: © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Fulltext Permission: none
Fulltext Availability: No Fulltext
Appears in Collections:SPMS Journal Articles

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