Facile fabrication of polypyrrole-coated silver nanoparticles: A novel and efficient surface-enhanced Raman scattering support for molecule detection

Abstract

Conducting polymer coated noble metal particles, particularly polypyrrole (PPy)-coated silver (Ag) nanoparticles can be efficient and unprecedented surface-enhanced Raman scattering (SERS) electrodes. Here in this work, a very simple and robust strategy has been adopted to achieve PPy-coated Ag nanoparticles and thereafter used for molecular detection through SERS technique. PPy-coated Ag nanoparticles were synthesized by polymerizing pyrrole in presence of Ag nanoparticles via a facile oxidative chemical polymerization approach. Field emissions scanning electron microscopy, energy dispersive spectroscopy, elemental mapping analysis, Fourier transform infrared spectroscopy and UV–Visible diffuse reflectance spectroscopy data revealed the formation and structure of PPy-coated Ag nanoparticles. Strong interaction between PPy and PPy-coated Ag nanoparticles was observed. As-synthesized PPy-coated Ag nanoparticles were utilized as SERS-active substrate for molecule detection. Rhodamine 6G was used as an analyte and a detection limit up to part per billion was achieved. A plausible mechanism has been highlighted in this regard. The SERS-active electrodes as investigated in this study not only provide an effective means to molecule detection in reactive environment but also facilitate a viable strategy to coat sensitive nanoparticles, such as noble and transition metal nanoparticles, with conductive polymers. To the best of our knowledge, there is no attempt taken yet to use PPy-coated Ag nanoparticles as SERS-active substrate through photodynamic approach for molecule detection.