Facile synthesis of large-scale Ag nanosheet-assembled films with sub-10Â nm gaps as highly active and homogeneous SERS substrates

► Homogeneous Ag nanosheet-assembled films were prepared via galvanic cell reactions. ► The morphology of the films can be controlled in conjunction with photolithography. ► The Ag nanosheet-assembled films exhibit highly active and homogeneous SERS effect. ► The films can be used as reliable SERS substrates for rapid detection of PCBs.