Facile Synthesis of Silver Nanoparticles with Application of Reproducible Surface Enhanced Raman Scattering Substrates

Surface enhanced Raman scattering (SERS) allows the determination of analytes at low concentrations on silver substrates. A novel facile method is reported to reproducibly synthesize large area SERS substrates. A composite of silver nanoparticles was fabricated by drop casting silver nitrate followed by thermal reduction to immobilize the nanoparticles on the surface. The morphology of the nanoparticles was characterized by optical and scanning electron microscopy, and the composition was evaluated by X-ray photoelectron spectroscopy. Reproducible substrates were prepared using Rhodamine 6G at concentrations from 1 to 50 µM as the SERS probe with relative standard deviations of 22% for ten locations on one sample. An inverse correlation between probe concentration and precision was obtained. The influence of microstructure morphology on the reproducibility was characterized; the more uniform the morphology of the silver microstructure, the better the precision of the substrates. Some silver patterns provided better precision than others, showing the significance of this work for basic and applied SERS.