Hybrid Plasmonic–Monolayer Transition Metal Dichalcogenide Heterostructures Obtained by Liquid-Assisted Origamization

We investigate the interplay between plasmonic coupling, dielectric screening, and mechanical deformation in folded hybrid plasmonic (Ag)–monolayer (1L) MoS2 heterostructures comprising various stacking configurations of the 1L MoS2 and Ag layer: MoS2–Ag, Ag–Ag–MoS2, MoS2–Ag–Ag–MoS2, and Ag–MoS2–Ag. These structures were obtained via liquid-induced folding of the 1L MoS2 covered with a continuous Ag film, and exhibit distinct optical and vibrational characteristics for each type of the stacking and thickness of the Ag film, fixed to 10 and 14 nm. Photoluminescence (PL) mapping reveals that thinner Ag films promote stronger X0A emission and higher neutral-to-trion intensity ratios, indicative of enhanced radiative recombination and reduced doping─likely due to suppressed plasmonic damping and nonradiative losses. Deconvoluted PL spectra show a progressive suppression of trion (X–) and B-exciton (X0B) features in thinner or encapsulated configurations, consistent with reduced charge transfer and exciton–plasmon quenching. The extracted trion binding energy increases from ∼25 meV in MoS2–Ag regions to ∼48 meV in sandwich-type structures, reflecting enhanced exciton confinement and reduced carrier screening. Raman spectroscopy reveals symmetry breaking and enhanced out-of-plane vibrational modes, with intensified A1g and A′ peaks in double-Ag configurations. The Raman mapping further indicates line width narrowing and frequency shifts associated with strain anisotropy, dielectric modulation, and plasmon–phonon interactions. These findings highlight the potential of geometry- and thickness-engineered 2D–metal hybrids for tunable excitonic and phononic functionalities in next-generation optoelectronic and nanophotonic devices.