2D transition metal dichalcogenides materials are explored as potential surface-enhanced Raman spectroscopy substrates. Herein, a systematic study of the Raman enhancement mechanism on distorted 1T (1T') rhenium disulfide (ReS ) nanosheets is demonstrated. Combined Raman and photoluminescence studies with the introduction of an Al O dielectric layer unambiguously reveal that Raman enhancement on ReS materials is from a charge transfer process rather than from an energy transfer process, and Raman enhancement is inversely proportional while the photoluminescence quenching effect is proportional to the layer number (thickness) of ReS nanosheets. On monolayer ReS film, a strong resonance-enhanced Raman scattering effect dependent on the laser excitation energy is detected, and a detection limit as low as 10 m can be reached from the studied dye molecules such as rhodamine 6G and methylene blue. Such a high enhancement factor achieved through enhanced charge interaction between target molecule and substrate suggests that with careful consideration of the layer-number-dependent feature and excitation-energy-related resonance effect, ReS is a promising Raman enhancement platform for sensing applications.

Plasmon-driven catalysis on a single particle has attracted great attention in recent years, while the relationship between reaction efficiency and substrate remains to be deeply studied. Here, we demonstrate the fabrication of a novel Ag@MoS 2 coreshell single particle SERS substrate by coating MoS 2 film on Ag microspheres through the pulsed laser deposition (PLD) technique, where the thickness and crystallinity of MoS 2 can be effectively controlled by the PLD time and temperature. It is revealed that both the thickness and crystallinity of MoS 2 can greatly influence the hot electron transfer process, and thus the plasmon-driven reaction (4-NTP into DMAB) efficiency and Raman enhancement of dye molecules on Ag@MoS 2 substrates. Generally, high crystallinity and thin thickness of MoS 2 can lead to accelerated plasmon-driven reaction efficiency and greatly enhanced Raman signals of target molecules. This study opens up a new avenue for broadening the research area of the plasmon-driven catalysis and Raman enhancement on the hybrid system of two-dimensional materials and metal nanostructures.

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