Surface-Enhanced Raman Scattering with Gold Core Silver Shell Nanoparticles

Nanotechnology is becoming increasingly important and has many different applications; understanding the chemical and physical properties of matter in this size regime is therefore important. Gold and silver nanoparticles are particularly interesting because they are relatively simple to make and they provide a substrate for surface-enhanced Raman scattering (SERS). SERS can be used to characterize how molecules adsorbed to silver or gold nanoparticles are orientated and if they react on the surfaces. When making silver nanoparticles, batch to batch variability of particle size and shape is high even though silver gives the best enhancement for SERS. This results in low reproducibility in SERS with silver. Gold nanoparticles are more consistent in shape from one batch to the next, but they do not give the enhancement that silver nanoparticles do. We are trying to address this limitation by making gold core silver shell nanoparticles that have the batch consistency of gold and enhancement close to silver. We are testing the gold core silver shell nanoparticles with p-(dimethyamino) cinnamic acid (DMACA) and p-aminocinnamic acid (ACA) to the surface of the nanoparticles.