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Sombrero-shaped plasmonic nanoparticles with molecular-level sensitivity and multifunctionality.

TitleSombrero-shaped plasmonic nanoparticles with molecular-level sensitivity and multifunctionality.
Publication TypeJournal Article
Year of Publication2011
AuthorsWi J-S, Barnard ES, Wilson RJ, Zhang M, Tang M, Brongersma ML, Wang SX
JournalACS Nano
Volume5
Issue8
Pagination6449-57
Date Published2011 Aug 23
ISSN1936-086X
KeywordsMagnetic Phenomena, Nanoparticles, Nanotechnology, Rhodamines, Silicon Dioxide
Abstract

We demonstrate top-down synthesis of monodisperse plasmonic nanoparticles designed to contain internal Raman hot spots. Our Raman-active nanoparticles are fabricated using nanoimprint lithography and thin-film deposition and are composed of novel internal structures with sublithographic dimensions: a disk-shaped Ag core, a Petri-dish-shaped SiO(2) base whose inner surface is coated with Ag film, and a sub-10 nm scale circular gap between the core and the base. Confocal Raman measurements and electromagnetic simulations show that Raman hot spots appear at the inside perimeter of individual nanoparticles and serve as the source of a 1000-fold improvement of minimum molecular detection level that enables detection of signals from a few molecules near hot spots. A multimodality version of these nanoparticles, which includes the functionality offered by magnetic multilayers, is also demonstrated. These results illustrate the potential of direct fabrication for creating exotic monodisperse nanoparticles, which combine engineered internal nanostructures and multilayer composite materials, for use in nanoparticle-based molecular imaging and detection.

DOI10.1021/nn201649n
Alternate JournalACS Nano
PubMed ID21732686
PubMed Central IDPMC3160147
Grant List1U54CA119367 / CA / NCI NIH HHS / United States
1U54CA151459 / CA / NCI NIH HHS / United States
R33CA138330 / CA / NCI NIH HHS / United States