Silver-coated PMMA nanoparticles on- a-mirror substrates as high performance SERS sensors for detecting infinitesimal molecules

              The Paper of the Day describes the fabrication and characterization of a high-performance surface-enhanced Raman scattering (SERS) substrate based on silver-coated PMMA nanoparticles on a silver mirror. The substrate was fabricated using a top-down approach involving reactive ion etching and magnetron sputtering. The presence of the silver mirror was found to enhance the electric field and SERS intensity compared to a substrate without the mirror. The thickness of the PMMA layer was optimized to match the absorption peak with the excitation laser wavelength, achieving maximum SERS intensity. The optimized substrate demonstrated excellent SERS performance for detecting crystal violet (CV) molecules, with a low detection limit of 10^-13 M. The substrate also exhibited excellent uniformity, with a relative standard deviation of 7.75% in peak intensities, and long-term stability over 37 days. The results suggest this approach can be a promising candidate for constructing high-performance SERS substrates for quantitative and qualitative detection.