Correlation of Size and Surface-Enhanced Raman Scattering Activity of Optical and Spectroscopic Properties for Silver Nanoparticles

The primary focus of this research is to investigate the potential correlations between the absorption band and surface-enhanced Raman scattering (SERS) activity of solution-based silver nanoparticles and the morphology and size of the silver nanoparticles. Silver nanoparticles were synthesized using sodium borohydride reduction methods. The silver nanoparticles were tested for SERS activity using a highly SERS-active compound, trans-1,2-bis(4-pyridyl)ethylene (BPE). Scanning transmission electron microscopy (STEM) was used to analyze the size and shape of the Ag nanoparticles. The STEM, SERS, and UV−vis data have been investigated in order to make correlations between SERS activity, size, and shape of the nanoparticles and their corresponding λmax or surface plasmon (SP) band. The data suggest that as particle size increases, SERS activity decreases. Thus, using the sodium borohydride reduction and solution-based SERS studies, there appears to be an optimal nanoparticle size that is obtained at a λmax of...