Entropy-engineered 2D TMDs for attomolar SERS sensitivity and universal resonant-non-resonant molecular detection

Abstract

Two-dimensional (2D) transition metal dichalcogenides (TMDs) have emerged as promising platforms for surface-enhanced Raman scattering (SERS) owing to their unique excitonic properties. However, the SERS performance of pristine TMDs is intrinsically constrained by their fixed electronic energy levels, which suppress charge transfer efficiency and limit molecular versatility. Here, we report an entropy-engineered 2D SERS platform, (VMoRe)S2, synthesized via a liquid precursor-assisted chemical vapor deposition process. The incorporation of V, Mo, and Re into the TMD lattice induces synergistic electronic and structural modulations, leading to the formation of abundant mid-gap states and localized lattice distortions. These features simultaneously enhance charge transfer resonance and strengthen molecular adsorption. Consequently, the (VMoRe)S2-based SERS substrate achieves ultrasensitive detection limits down to 1 & times; 10-18 M for rhodamine 6G and 1 & times; 10-12 M for various analytes. Beyond standard dye detection, (VMoRe)S2 also enables the SERS detection of glucose (2 & times; 10-2 M), a physiologically relevant biomolecule with a non-resonant Raman signature. These findings demonstrate the exceptional sensitivity, molecular versatility, and structural robustness of (VMoRe)S2, presenting a powerful strategy for advancing chemical sensing and practical molecular diagnostics beyond the limitations of conventional TMD-based SERS platforms.