文摘
We report silver nanoparticles (Ag NPs) with high stability, sensitivity, and no surface enhanced Raman scattering (SERS) background. The Ag NPs were synthesized via a one-step process with polysodium styrenesulfonate (PSSS) templates, and they could efficiently adsorb polycyclic aromatic molecules via π–π stacking. The adsorption mechanisms and applicability were systematically studied by experimental measurements and theoretical simulations. When the polycyclic aromatic analytes were adsorbed on the PSSS-templated Ag NPs, the vibrations of π–π stacking-bound moieties were attenuated, yet those of the other unbound aromatic moieties increased. Most importantly, when the analytes had more than two π–π stacking binding sites, the PSSS-templated Ag NPs could trap the analytes by focusing through the optical force induced or via the simultaneously formed analyte–Ag NPs aggregates. This afforded high SERS intensity and very low detection limits.
