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.