摘要： Electromagnetic hotspots at the interstices of plasmonic assemblies are recognized to be the most potent sites for surface enhanced Raman scattering (SERS). We demonstrate a novel “add-on” electromagnetic hotspot formation technique, which significantly improves the sensitivity of conventional SERS substrates comprised of individual plasmonic nanostructures. The novel approach demonstrated here involves the transfer of “plasmonic patch”, a transparent, flexible and conformal elastomeric film adsorbed with plasmonic nanostructures, onto a conventional SERS substrate. The addition of plasmonic patch onto conventional SERS substrate following the analyte capture results in the formation of electromagnetic hotspots and hence large SERS enhancement. The application of plasmonic patch improves the sensitivity and limit of detection of conventional SERS substrates by upto ~100-fold. The transfer of plasmonic patch also effectively transforms the SERS-inactive gold mirror to a highly SERS-active “particle-on-mirror” system. Furthermore, we demonstrate that the “add-on” technique can be effectively utilized for the vapor phase detection of explosives such as trinitrotoluene (TNT) using peptide recognition elements. We believe that the on-demand hotspot formation approach presented here represents a highly versatile and ubiquitously applicable technology readily expandable to any existing SERS substrate without employing complicated modification.