Toward low-cost and sustainable SERS substrate: novel ultrasensitive AMS5 nanoflowers

Abstract

Surface-enhanced Raman scattering (SERS) is an analytical technique for the rapid detection of low-concentration analytes. However, the lack of uniform, stable, and recyclable substrate limits its wide applications. Here, Ag-doped MoS₂ (AMS_x) was prepared by the hydrothermal method. Band structures, LSV, and EIS characteristics confirmed that Ag doping can reduce the indirect band gap and increase the charge transfer between substrates and molecules. As a SERS substrate, AMS_x displays excellent reproducibility, stability, and recyclability, which is beneficial for the application of the SERS substrate. Meanwhile, AMS_x has excellent sensitivity with an enhancement factor of 4.07 × 10⁶, comparable to that of precious metals. In addition, AMS_x exhibits ultrahigh sensitivity in sensing bilirubin and Bisphenol A (BPA); the corresponding detection limit of both is 10⁻⁹ M, also better than that of previously reported semiconductors. This work provided a novel idea to synthesize low-cost ultrasensitive SERS substrates and the strategy of improving metal-chalcogenide semiconductor sensing.