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

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 <i>via</i> 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.