SERS detection for pesticide residue via a single-atom sites decoration strategy

Surface-enhanced Raman scattering (SERS) is a promising technique for detecting trace analytes, but the design of hotspots with nanoscale precision remains a challenge for achieving accurate detection. Here, photoinduced-synthesized single-atom sites Ag are uniformly dispersed on an Au nanostructure to form hierarchical hotspots. The precise control of hotspots exhibits significantly improved SERS performance with an enhancement factor (EF) of more than 109 and great Raman signal quantification for pesticide residue acetamiprid and cycocel. The superiority of the precise structure of hierarchical hotspots can be ascribed to structure uniformity and enhanced electronegativity, leading to a limit of detection (LOD) of down to 0.1 ppb and notable improvement of Raman signals stability compared with bare Au nanostructure. The LOD is among the best SERS substrates in literatures. Furthermore, the precise hotspot modification approach can be identified immediately by coloration under sunlight and applied to a SiO2 substrate to avoid the Ag oxidation in ambient conditions. Thus, the simple and effective SERS enhancement method via single-atom site decoration strategy is anticipated to shed light on practical sensing detection.