Photoluminescence Properties of Gold Nanorod and J-Aggregate Hybrid Systems Studied by Scanning Near-Field Optical Microscopy

Plasmons excited in metal nanostructures couple strongly with excitons in organic aggregates in the vicinity of the structure. The photoluminescence properties of plasmon-exciton hybrids have been studied, and peak splitting of the photoluminescence has been reported. However, the origin of the splitting is under discussion and remains to be solved. In this study, we investigate the photoluminescence properties of single-gold nanorod and J-aggregate hybrids using dark-field scattering and near-field optical microscopy. We reveal from the dark-field scattering and near-field transmission measurements that the hybrids are under a strong coupling regime. Near-field photoluminescence microscopy demonstrates that photoluminescence enhancement at the hybrid reaches more than 15-fold, and the enhancement is correlated with the reduced damping in the coupled states.