Flexible plasmonic nanoparticle-on-a-mirror metasurface-enabled substrates for high-quality surface-enhanced Raman spectroscopy detection

Surface-enhanced Raman scattering (SERS) technology with the advantages of ultra-high sensitivity, nondestructive analysis, and quick measurement for molecular detection applications is receiving increasing attention. However, traditional rigid SERS substrates face challenges in in-suit conformal detection and weak structure coupling effect for real-life applications. Here we report a flexible polydimethylsiloxane (PDMS) substrate loaded with plasmonic nanoparticle-on-a-mirror (NPOM) metasurface for SERS detection that featured outstanding sensitivity, uniformity, repeatability, and excellent mechanical flexibility. The upper multilayered NPOM metasurface can be fabricated in a single-step process by ion beam sputtering of various targets. This NPOM configuration consists of dense silver nanoparticles over a silver mirror, separated by a SiO2 spacer layer, which can realize near-total power absorption and exhibits superior SERS ability. The bottom PDMS layer for support can provide excellent mechanical properties. In the test, the as-prepared NPOM/PDMS substrates show high SERS performance in detecting crystal violet and chlorpyrifos molecules. This flexible metasurface SERS substrate promises to provide an in-suit and efficient approach for trace substance detection.