An in situ approach for facile fabrication of robust and scalable SERS substrates

The widespread implementation of surface enhanced Raman scattering (SERS) techniques for chemical and biological detection requires an inexpensive, yet robust SERS substrate with high sensitivity and reproducibility. To that end, we present a facile method to fabricate plasmonic SERS substrates with well-distributed SERS "hot spots" on a large scale with reproducible SERS enhancement factors of ∼10⁸ for the Raman probe molecule 4-aminobenzenethiol (4-ABT). The SERS enhancement is attributed to the synergistic interactions between the strong plasmonic coupling among the assembled Au NPs and the structure-associated tip enhancement. Additionally, these mechanically-flexible substrates exhibit remarkably reproducible SERS signals, demonstrating the merits of our methodology. Our approach illustrates the potential opportunities for fabricating robust, commercially-viable SERS substrates with well-distributed "hot spots" on a large scale while avoiding costly vacuum deposition technologies.