▎ 摘　　要

Silver nanoparticles/graphene oxide(AgNPs/GO) films with few-layer GO were prepared through alternating deposition of GO sheets and positively charged AgNPs via electrostatic self-assembly approach. The formation and surface morphology of prepared substrates were characterized by UV-Vis spectra, AFM and SEM. The results show that the AgNPs/GO substrates with "Sandwich" structure and AgNPs aggregates can be obtained by the control of concentration of AgNPs colloid and self-assembly cycles. The SERS performances show that the AgNPs/GO-4 substrate has the optimal SERS activity. The average analytical enhancement factors(AEFs) of this substrate towards Rhodamine 6G and crystal violet are 3.4x10(8) and 1.3x10(9), respectively, and the minimum detectable concentration of R6G is 10(-12) mol/L. Due to the "Sandwich" structure and strong coupling effect of narrow interparticle distance, abundant "hot spots" can be generated in GO sheets, resulting in improved SERS activity. Furthermore, the strong adsorption ability of few-layer GO is beneficial for enrichment of molecules in substrate, providing the chemical enhancement effect and improving the SERS sensitivity.