Hot Electrons Control of Quantum Dot Emission Using Plasmonic Supercells.

In hybrid systems composed of metallic nanoantennas and semiconductor quantum dots (QDs), exciton-plasmon coupling plays a central role in controlling the emission intensity and dynamics of the QDs. Here, we investigate how plasmon decay into hot electrons modulates this coupling through electronic modification of the QD environment. The plasmonic platform consists of closely packed periodic arrays of elongated Au nanoantennas that support plasmonic supercells. Owing to their periodicity, these supercells, formed via near-field coupling along the long axes or through hybrid plasmonic-photonic edge coupling, support plasmonic hot-spots and surface lattice resonances (SLRs), supporting enhanced hot-electron generation. The arrays are coated with a thin Si interlayer followed by an ultrathin InP/ZnS QD film, providing both dielectric coupling and electronic pathways for charge transfer. We show that hot electrons injected across the Au/Si interface can charge the environment of QDs, resulting in a polarization-dependent blue shift of the emission of QDs, accompanied by enhancement of their emission lifetime. These results highlight the key roles of SLRs and plasmonic hot spots in enabling hot-electron-mediated control of QD emission.