[Electrochemical synthesis and spectroscopic characterization of gold nanoparticles]

Two electrochemical methods were used to synthesize Au nanoparticles (AuNPs) with different shapes depending on the applied current. The dumbbell, spheroid and rod-like AuNPs were synthesized by increasing the current with a certain increment, while spheroid and dumbbell AuNPs were obtained by applying constant current. The AuNPs were characterized by TEM, UV-Vis spectrum and surface enhanced Raman spectra (SERS). One absorption band located at near-IR region was observed on the AuNPs, indicating the existence of gold nanorods with the aspect ratio of about 6. The SERS effect from the AuNPs surface was studied by using crystal violet as probe molecules, which adsorbed on AuNPs surface with flat orientation. Meanwhile, the forming mechanism of AuNPs involving crystallization and growth was deduced based on the TEM results.