▎ 摘　　要

Surface-enhanced Raman spectroscopy (SERS) as a powerful analytical tool has gained extensive attention. Despite of many efforts in the design of SERS substrates, it remains a great challenge for creating a universal substrate with long-term stability and reproducible SERS signals. In this work, Ag nanocubes and graphene oxide (GO) suspension were mixed to form a stable solution and further vacuum filtrated to obtain a free-standing hybrid paper. The Ag/GO hybrid papers exhibit excellent SERS activity because of the synergistic effect of Ag nanocubes and GO sheets. GO sheets can act as both SERS enhancement substrate and framework for supporting Ag nanocubes. Moreover, GO sheets can protect Ag nanoparticles from oxidation under ambient condition for prolonged life time SERS substrate. Furthermore, we demonstrate the use of the free-standing and flexible Ag/GO hybrid paper to enable direct, real-time and reliable detection of trace amounts of analytes in aqueous systems. This novel SERS substrate is expected to be applied in real-time analysis and expands the flexibility of SERS for useful applications in the materials and life science.