Gyroid-structured Au–Ag periodic bimetal materials for ultrasensitive SERS detection

Abstract

Surface enhanced Raman scattering (SERS) has attracted much research attention for analysis and trace detection. In this work, we fabricated a gyroid-structured Au–Ag bimetal plasmonic material GSPMMs@Au by incorporating gyroid-structured silver periodic metallic materials (GSPMMs) with Au nanoparticles (NPs). By controlling the galvanic reaction time, we found that the highest surface plasmonic resonance enhancement among all the samples can be acquired with a deposition time of 50 s (GSPMMs@Au50). Finite-difference time domain simulation results prove that plasmonic coupling between the Au–Ag interface dramatically enhances the SERS performance. The SERS detection limit of bis(2-ethylhexyl) (DEHP) molecules based on GSPMMs@Au50 was 3.4 × 10⁻¹⁸ M, which is the best result among recently published studies.