Precursor-Driven Nucleation and Growth Kinetics of Gold Nanostars

Recently, seed-mediated approach has been widely utilized for synthesizing monodisperse gold nanostars well-known for plasmonic and sensing applications. Herein, we report a single step seedless/templateless organic synthesis procedure for the complex 3D gold nanostars with a high degree of size/shape control, involving the complexation of polyvinylpyrrolidone (PVP) in polar solvent N,N-dimethylformamide (DMF) and their reduction of AuCl4 ions along with hydrochloric acid (HCl) as an effective mediator. On the basis of the kinetic optical absorption and Fourier transform infrared (FTIR) spectroscopy measurements, a convenient ligand exchange mechanism has been proposed for the first time to the best of our knowledge to understand the evolution of these complex shaped gold nanostructures. The coordination interaction among PVP and DMF as well as PVP-DMF-AuCl4 has been identified as the major driving factors influencing the temporal evolution of the size/shape-controlled gold nanostars.