Structure-activity relationships in gold nanoparticle dimers and trimers for surface-enhanced raman spectroscopy

Kristin L. Wustholz, Anne Isabelle Henry, Jeffrey M. McMahon, R. Griffith Freeman, Nicholas Valley, Marcelo E. Piotti, Michael J. Natan, George C. Schatz, Richard P.Van Duyne

Research output: Contribution to journalArticlepeer-review

700 Scopus citations


Understanding the detailed relationship between nanoparticle structure and activity remains a significant challenge for the field of surface-enhanced Raman spectroscopy. To this end, the structural and optical properties of individual plasmonic nanoantennas comprised of Au nanoparticle assemblies that are coated with organic reporter molecules and encapsulated by a SiO2 shell have been determined using correlated transmission electron microscopy (TEM), dark-field Rayleigh scattering microscopy, surface-enhanced Raman scattering (SERS) microscopy, and finite element method (FEM) calculations. The distribution of SERS enhancement factors (EFs) for a structurally and optically diverse set of nanoantennas is remarkably narrow. For a collection of 30 individual nanoantennas ranging from dimers to heptamers, the EFs vary by less than 2 orders of magnitude. Furthermore, the EFs for the hot-spot-containing nanoparticles are uncorrelated to aggregation state and localized surface plasmon resonance (LSPR) wavelength but are crucially dependent on the size of the interparticle gap. This study demonstrates that the creation of hot spots, where two particles are in subnanometer proximity or have coalesced to form crevices, is paramount to achieving maximum SERS enhancements.

Original languageEnglish
Pages (from-to)10903-10910
Number of pages8
JournalJournal of the American Chemical Society
Issue number31
StatePublished - 11 Aug 2010
Externally publishedYes


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