Plasmon-trion and plasmon-exciton resonance energy transfer from a single plasmonic nanoparticle to monolayer MoS2

Resonance energy transfer (RET) from plasmonic metal nanoparticles (NPs) to two-dimensional (2D) materials enhances the performance of 2D optoelectronic devices and sensors. Herein, single-NP scattering spectroscopy is employed to investigate plasmon-trion and plasmon-exciton RET from single Au nanotriangles (AuNTs) to monolayer MoS2, at room temperature. The large quantum confinement and reduced dielectric screening in monolayer MoS2 facilitates efficient RET between single plasmonic metal NPs and the monolayer. Because of the large exciton binding energy of monolayer MoS2, charged excitons (i.e., trions) are observed at room temperature, which enable us to study the plasmon-trion interactions under ambient conditions. Tuning of plasmon-trion and plasmon-exciton RET is further achieved by controlling the dielectric constant of the medium surrounding the AuNT-MoS2 hybrids. Our observation of switchable plasmon-trion and plasmon-exciton RET inspires new applications of the hybrids of 2D materials and metal nanoparticles.