Huang, DaByers, Chad P.Wang, Lin-YungHoggard, AnneliHoener, BenChang, Wei-ShunLandes, Christy F.Link, Stephan2015-10-012015-10-012015Huang, Da, Byers, Chad P., Wang, Lin-Yung, et al.. "Photoluminescence of a Plasmonic Molecule." <i>ACS Nano,</i> 9, no. 7 (2015) American Chemical Society: 7072-7079. http://dx.doi.org/10.1021/acsnano.5b01634.https://hdl.handle.net/1911/81858Photoluminescent Au nanoparticles are appealing for biosensing and bioimaging applications because of their non-photobleaching and non-photoblinking emission. The mechanism of one-photon photoluminescence from plasmonic nanostructures is still heavily debated though. Here, we report on the one-photon photoluminescence of strongly coupled 50 nm Au nanosphere dimers, the simplest plasmonic molecule. We observe emission from coupled plasmonic modes as revealed by single-particle photoluminescence spectra in comparison to correlated dark-field scattering spectroscopy. The photoluminescence quantum yield of the dimers is found to be surprisingly similar to the constituent monomers, suggesting that the increased local electric field of the dimer plays a minor role, in contradiction to several proposed mechanisms. Aided by electromagnetic simulations of scattering and absorption spectra, we conclude that our data are instead consistent with a multistep mechanism that involves the emission due to radiative decay of surface plasmons generated from excited electron–hole pairs following interband absorption.engThis is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by the American Chemical Society.Journal articlephotoluminescencesurface plasmongold nanoparticlenanoparticle dimerplasmon couplinghttp://dx.doi.org/10.1021/acsnano.5b01634