Plasmonic Grating on Monolayer MoS2for Strong Photoluminescence Enhancement and Ultrasensitive Surface-Enhanced Raman Scattering (SERS) Detection

Abstract

Monolayer MoS<inf>2</inf>, a key 2D transition metal dichalcogenide (TMDC), offers strong potential for next-generation optoelectronic devices due to its direct bandgap and tunable optical properties. However, its ultrathin structure results in inherently weak light–matter interactions and limited photoluminescence (PL) output. Here, we demonstrate a scalable strategy for enhancing the optical response of monolayer MoS<inf>2</inf>using plasmonic nanoresonators patterned via capillary-force-assisted assembly of the thermoresponsive polymer poly(ε-caprolactone) (PCL), eliminating complex nanofabrication. Subsequent deposition of plasmonic metals (Au, Ag, Al) forms well-defined resonator arrays, enabling sequential fabrication of multiple patterns on a single layer. Optimized Au gratings (818 nm width, 2.6 nm thickness) achieved over 390-fold PL enhancement through efficient exciton–plasmon coupling. Moreover, the crossbar-type Au–Au gratings on MoS<inf>2</inf>exhibited remarkable surface-enhanced Raman scattering (SERS) sensitivity, enabling detection of rhodamine 6G down to 10–18M. This practical approach significantly amplifies light–matter interactions in 2D materials, advancing their integration into flexible photonic, sensing, and optoelectronic systems. © 2025 American Chemical Society