Research on developing SERS substrates based on a ZnO porous membrane decorated with silver nanoparticles aimed at detecting low concentrations of Rhodamine B

Abstract

Recently, Ag-decorated ZnO has been explored for detecting the residual organic toxins through surface-enhanced Raman scattering (SERS), based on the local surface plasmonic resonance (LSPR) effect. In this study, we presented the composite of Ag/ZnO nanoparticles with a porous structure, supported by polystyrene (PS), for fabricating SERS substrates to detect Rhodamine B (RhB) at low concentration. In this structure, Ag nanoparticles (NPs) enhance the Raman signals via the electromagnetic mechanism (EM), while ZnO contributes to signal enhancement through the chemical mechanism (CM). PS microspheres improve the adhesion of Ag/ZnO on substrates and enable the formation of a porous structure in the membrane. At an excitation wavelength of 532 nm, the SERS intensity of RhB at 1645 cm⁻¹ exhibits a linear relationship with RhB concentration. The limit of detection (LOD) and enhancement factor (EF) for the porous Ag/ZnO structure are calculated to be 7.9 × 10⁻⁶ ppm and 3.08 × 10⁶, respectively. The innovative porous architecture is advantageous for Raman signal generation and therefore well-suited for detecting residual organic toxins in agricultural products.