Engineering moiré potentials in twisted bilayer MoS2 for selective single-molecule sensing

Twisted bilayer MoS2 forms a quantum-engineered sensing platform, where the moiré superlattice creates a configurable surface potential for molecular control. Here we present a periodically modulated landscape in bilayer MoS2 by twist-angle tuning, and use it for molecular trapping and selective sensing. The native 54 meV moiré potential confines aromatic molecules (e.g., rhodamine 6G, R6G; methylene blue, MB) at AA-stacking sites. Introducing extended vacancies deepens confinement to 238 meV, enhancing adsorption. Twist angle enables band alignment with molecules, driving charge-transfer resonances. This integrated design, moiré potentials, defect-enhanced trapping and band-aligned charge transfer, synergistically amplifies Raman signals, achieving single-molecule sensitivity down to 10−20 M. Importantly, the platform exhibits molecule-specific selectivity: R6G is optimally detected at 10° and 50° bilayer MoS2, while MB responds at 15° and 45°, demonstrating twist-angle encoding of molecular recognition. Our twisted MoS2 with extended vacancies establishes a moiré system as a versatile platform for selective molecular sensing. Twisted layers of van der Waals materials can generate moiré superlattices, forming reconfigurable surface potentials with nanoscale periodicity. Here, the authors show that the moiré potential in twisted bilayer MoS2 can be used to confine aromatic molecules, improving the surface-enhanced Raman spectroscopy sensitivity and selectivity of this platform.