Tuning resonance coupling between Au nanorod and WS2 by chemical treatment

Abstract

Hybrid system composed of metal nanoparticles and two-dimensional transition metal dichalcogenides (TMDs) is important for studying the light-matter interaction at the nanoscale. In particular, the 2D excitons are very sensitive to external stimulus, allowing their active control via temperature scanning, gating, and optical excitation. In comparison with other active tuning strategies, chemical treatment is another effective method. In this study, we realize tuning of the resonance coupling, through a chemical approach, in heterostructure composed of an individual gold nanorod integrated with monolayer WS2 flake. Treating the heterostructure with an organic superacid: bis(trifluoromethane)sulfonimide (TFSI), the photoluminescence intensity can be enhanced by 7 times. The coupled system has enhanced energy splitting about 50 meV. The chemical treatment based on the TFSI solution provides a new approach for tuning the resonance coupling effect.