Plasmon-Enhanced Emission in Gold Nanoparticle Aggregates

We have investigated the influence of the plasmon resonances of individual, spatially isolated gold nanoparticle aggregates on their emission properties using combined optical confocal and dark field scattering microscopy and spectroscopy. The emission intensity of the same aggregate is enhanced by up to 1 order of magnitude if the emission wavelengths overlap with the plasmon resonance in the corresponding white light scattering spectrum. Regardless of the specific geometry of an individual aggregate, the in situ measurement of the plasmon characteristics delivers unique information about its potential as a substrate for surface-enhanced spectroscopy and allows its characterization as a nanoscatterer, nanoemitter, or local heater.