Sulfur Vacancies‐Triggered High SERS Activity of Molybdenum Disulfide for Ultrasensitive Detection of Trace Diclofenac

Abstract Due to the efficient photoinduced charge transfer properties of nonmetals, nonmetallic surface‐enhanced Raman scattering (SERS) substrates have been advanced rapidly these years. And among of these, molybdenum disulfide (MoS₂) is perceived as one of the most representative nonmetallic SERS substrates due to its abundant active sites. However, its progress in SERS field is severely hindered because of the lower SERS activity. Herein, one type of vacancies‐triggered highly sensitive SERS substrate based on nanostructured MoS₂ with sulfur vacancies (V_S) is proposed. The V_S‐MoS₂ substrates are intended to promote the SERS performance through the V_S density regulation. Intrinsically, moderate V_S can change the bandgap structure of MoS₂, thus promoting the separation of internal carriers and enhancing the interaction with target species. Externally, the presence of V_S can bring abundant adsorption sites on MoS₂ surface, which greatly improves its ability to enrich target molecules. Both internal and external properties make V_S‐MoS₂ a high SERS activity substrate. Moreover, with the antibiotic contaminant diclofenac as a model probe molecule, the V_S‐MoS₂ substrate can accurately perceive its nanomolar concentration level with an enhancement factor up to 5.85 × 10³. This work demonstrates exciting potential for analysis in real water environments based on nonmetallic SERS applications.