Silver–Gold Nanostructures on ITO and Glass for SERS-Based Detection of Environmental Organic Dyes

The rapid and ultrasensitive detection of trace organic pollutants, including synthetic dyes and pesticide residues, in aquatic environments is critically important for environmental monitoring and food safety assurance. While surface-enhanced Raman scattering (SERS) serves as a powerful analytical tool for such molecular trace analysis, its practical implementation depends strongly on the development of stable, cost-effective, and highly enhancing plasmonic platforms. In this study, we successfully developed and systematically evaluated four distinct SERS substrates based on indium tin oxide (ITO) decorated with silver nanoparticles (Ag NPs) and gold nanoparticles (Au NPs), as well as glass with silver nanoflowers (Ag NFs). The ITO-based substrates (ITO-Au, ITO-APTES-Au, and ITO-Ag) were fabricated via an electrochemical deposition strategy, whereas the glass-silver (G-Ag) substrates were synthesized through a facile wet-chemical approach. Among the fabricated platforms, the G-Ag platform exhibited the best analytical performance, achieving ultralow limits of detection (LOD) of 2.16 × 10–13 M for methylene blue, 1.96 × 10–12 M for rhodamine B, and 1.8 × 10–10 M for another analyte, alongside a remarkable maximum enhancement factor (EF) of 8.85 × 1010. In addition, the G-Ag platform is promising for development in biomedicine, food safety control, environmental pollutant monitoring, and trace forensic analysis.