Electrochemical Synthesis and Deposition of Surface-Enhanced Raman Scattering-Active Silver Microstructures on a Screen-Printed Carbon Electrode

We demonstrated a series of Ag microstructures with controlled morphologies directly deposited on a screen-printed carbon electrode by using electrochemical procedures in the presence of different electrolytes. Scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and high-resolution X-ray diffractometry were used for characterizing as-prepared Ag substrates. Thereafter, the potential of the flower-like Ag microstructures for use in surface-enhanced Raman scattering (SERS) applications was investigated. The flower-like Ag microstructures provided a more intense SERS signal because of extremely intense local electromagnetic fields. The enhancement factor value was approximately 1.2 × 10⁶ for 4-mercaptobenzoic acid molecules. The percentage of relative standard deviation of SERS signals was lower than 2.1%. Determining the SERS spectra of 4,4′-dimercapto-azobenzene, 5,5′-dithiobis-2-nitrobenzoic acid, adenine, and single-stranded DNA (fumarylacetoacetate hydrolase gene) was straightforward. Furthermore, the thermal stability and aging behavior of the microstructures were improved. The present substrate fabrication process is facile and has excellent SERS-active properties and reproducibility and thus provides opportunities for quantitative analysis by using flower-like Ag microstructures.