Exploring the Potential of Electrospun Polymer-Coated Ag Nanofibers for Synergistic SERS Performance and Real-World Applications

Electrospinning is a prominent technique for fabricating polymer-stabilized composite nanofibers for surface-enhanced Raman scattering (SERS). However, further exploration of the surface chemistry of these electrospun composite substrates is crucial to manipulate the charge transfer (CT) effect and achieve synergistic effects between CT and localized surface plasmon resonance (LSPR) for enhanced bio-labeling and pesticide detection. Here, we present the development of a flexible and self-supporting SERS substrate using electrospinning, consisting of polymer-coated silver nanowires (AgNWs). By employing different polymer shells and probe molecules, we strategically adjusted the energy levels of the frontier orbitals, enabling effective control over the CT effect. The resulting nanofibers exhibited optimized selectivity and sensitivity through multiple CT routes, enabling the detection of thiram in apple skin using a convenient wiping sampling method with a low limit of detection (LOD) of 5 ng/cm². We also investigated other pesticides without viable CT routes to demonstrate the versatility of the composite substrates, although they exhibited relatively lower selectivity and sensitivity due to the absence of synergistic effects. This study highlights the potential of CT manipulation in harnessing synergistic effects in electrospun 2D composite nanofibers, thereby advancing the practical applications of SERS technology.