TY - JOUR
T1 - Structure-activity relationships in gold nanoparticle dimers and trimers for surface-enhanced raman spectroscopy
AU - Wustholz, Kristin L.
AU - Henry, Anne Isabelle
AU - McMahon, Jeffrey M.
AU - Freeman, R. Griffith
AU - Valley, Nicholas
AU - Piotti, Marcelo E.
AU - Natan, Michael J.
AU - Schatz, George C.
AU - Duyne, Richard P.Van
PY - 2010/8/11
Y1 - 2010/8/11
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=77955373367&partnerID=8YFLogxK
U2 - 10.1021/ja104174m
DO - 10.1021/ja104174m
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C2 - 20681724
AN - SCOPUS:77955373367
SN - 0002-7863
VL - 132
SP - 10903
EP - 10910
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 31
ER -