Plasmon-exciton coupling of monolayer MoS₂-Ag nanoparticles hybrids for surface catalytic reaction

Summary, in English

The optical properties of monolayer molybdenum disulfide (MoS₂)/Ag nanoparticle (NP) hybrids and their application to surface catalytic reactions were studied by transmission, photoluminescence (PL) and Raman spectroscopies. The local surface plasmon resonance (LSPR) of Ag nanoparticles was tuned to better match the exciton energy of monolayer MoS₂. The PL of the hybrids was enhanced by more than 50 times when the local surface plasmon resonance (LSPR) peak was tuned systematically from 438 nm to 532 nm, indicating a stronger coupling and higher energy transfer rate between the plasmon of the Ag NPs and the excitons of the MoS₂. Additionally, photocatalytic reactions of 4-nitrobenzenethiol (4NBT) were performed on the MoS₂, the Ag nanoparticles, and the hybrid MoS₂ with Ag nanoparticles. On the MoS₂ substrate alone, there is no photocatalytic reaction. With a low laser intensity, the probability of a chemical reaction occurring for molecules directly adsorbed onto the Ag NPs is much lower than the probability of a reaction involving those molecules adsorbed onto the MoS₂/Ag substrate. At a higher power, although the electric field was reduced by approximately 30% by the MoS₂ layer, there is better efficiency for the plasmon-exciton co-driven surface catalytic reactions on the MoS₂/Ag substrate compared to the Ag substrate alone. Our findings illustrate the potential to control hot carriers for better surface catalytic reactions by tuning the exciton-plasmon coupling between the 2D transition metal dichalcogenides (TMDCs) and Ag NPs.