Chiral Ag/Bi 6 S 2 O 15 Hybrid NWs Film Tailored Intense SERS Activity for Sensitive Detection Application

ABSTRACT Chiral nanostructures with enhanced synergistic and anisotropic plasmonic coupling, and large‐scale structural effect can help to induce giant chiroptical activity. Here, Ag nanowires (NWs) films were fabricated and generated strong circular dichroism (CD) in the range of 200–2000 nm by adjusting the number and the angle of layers. Chiral Ag NWs films exhibited a significant selective differential plasmonic coupling effect as indicated by circularly polarized light (CPL)‐surface enhanced Raman scattering (SERS) and photocurrent result. Chiral Ag NWs films exhibited chirality‐enhanced plasmon resonance effects under linearly polarized light excitation, and induced intense photocurrent and SERS intensity. Chiral Ag NWs films exhibit stronger SERS intensity than achiral Ag NWs film. The SERS intensity of chiral Ag NWs film was further amplified by stacking of ordered Bi 6 S 2 O 15 NWs film, with the SERS signal of chiral hybrid NWs film reaching 2.0 times of achiral Ag NWs film. This SERS‐active film enabled label‐free and sensitive detection of ergothioneine (EGT, a potent mitochondria‐targeted antioxidant), with a detection limit of 0.25 µg/mL. This method provides a new approach to design SERS substrates by employing chiral nanostructures and high‐permittivity semiconductors, for the study of antioxidant changes in the process of combating free radical damage and delaying cellular senescence.