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Abstract Strong light-matter interactions in localized nano-emitters placed near metallic mirrors have been widely reported via spectroscopic studies in the optical far-field. Here, we report a near-field nano-spectroscopic study of localized nanoscale emitters on a flat Au substrate. Using quasi 2-dimensional CdSe/Cd_xZn_1-xS nanoplatelets, we observe directional propagation on the Au substrate of surface plasmon polaritons launched from the excitons of the nanoplatelets as wave-like fringe patterns in the near-field photoluminescence maps. These fringe patterns were confirmed via extensive electromagnetic wave simulations to be standing-waves formed between the tip and the edge-up assembled nano-emitters on the substrate plane. We further report that both light confinement and in-plane emission can be engineered by tuning the surrounding dielectric environment of the nanoplatelets. Our results lead to renewed understanding of in-plane, near-field electromagnetic signal transduction from the localized nano-emitters with profound implications in nano and quantum photonics as well as resonant optoelectronics. 

Investigation of charge transfer in quantum dot (QD) systems is an area of great interest. Specifically, the relationship between capping ligand and rate of charge transfer has been studied as a means to optimize these materials. To investigate the role of ligand interaction on the QD surface for electron transfer, we designed and synthesized a series of ligands containing an electron accepting moiety, naphthalene bisimide (NBI). These ligands differ in their steric bulk: as one allows for π–π stacking between the NBI moieties at high surface coverages, while the other does not, allowing for a direct comparison of these effects. Once grafted onto QDs, these hybrid materials were studied using UV-Vis, fluorescence, and transient absorption spectroscopy. Interestingly, the sample with the fastest electron transfer was not the sample with the most NBI π–π stacking, it was instead where these ligands were mixed amongst oleic acid, breaking up H-aggregates between the NBI groups.