Tuning the SERS activity and plasmon-driven reduction of p-nitrothiophenol on a Ag@MoS2 film
The combination of plasmonic metal nanostructures with semiconductors has been widely applied in plasmon-driven photocatalysis. Here, a uniform Ag@MoS2 hybrid film is fabricated by depositing MoS2 onto a thin Ag film via the pulsed laser deposition (PLD) technique. The thickness and crystallinity of MoS2 can be adjusted by controlling the PLD deposition time and temperature, respectively. With the assistance of surface-enhanced Raman scattering (SERS) analysis, the Raman enhancement uniformity of the substrate and plasmon-driven reaction of p-nitrothiophenol (PNTP) dimerizing into p,p′-dimercaptobenzene (DMAB) are carefully studied on Ag@MoS2 film substrates with different MoS2 crystallinities. The Raman enhancement decreases with increased MoS2 thickness, due to the weakened electromagnetic field enhancement as suggested by finite-difference time-domain (FDTD) simulations. The increased crystallinity of MoS2 can efficiently accelerate the hot electron transfer process, resulting in the enhancement of SERS activity and the improved efficiency of the plasmon-driven reaction. This study may pave the way for the design of other uniform metal–semiconductor hybrids for use as SERS substrates and photocatalysts.
- This article is part of the themed collection: Hot-electron science and microscopic processes in plasmonics and catalysis