We investigate the correlation between electron energy loss spectroscopy (EELS) and optical properties of single molecule surface-enhanced Raman scattering (SMSERS) active nanoparticles. It is well established that the gap regions (hot-spots) between two closely spaced metallic nanoparticles play a significant role in observing SMSERS. To this end, we employ EELS to image plasmon modes of the hot-spots, especially those containing two closely spaced nanoparticles, to obtain spatial maps of the localized surface plasmon modes.  The Bi-analyte approach using two isotopologues of Rhodamine 6G in silver nanoparticles is used to identify SMSERS active nanoparticles. Raman scattering and resonant-Rayleigh scattering are recorded employing a micro-Raman setup and the EEL spectra of the exact same SMSERS active nanoparticles measured utilizing scanning transition electron microscopy. This study reveals new information on the bright and dark field plasmon modes of the SMSERS active nanoparticles and may yield complementary information on their photonic density of state.

Electron energy loss spectroscopy of single molecule surface-enhanced Raman scattering hot spots

243rd National Meeting (2012)

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