Formation of gold nanoparticles and self-assembly into dimer and trimer aggregates

Gold nanoparticles synthesized by in situ chemical reduction of HAuCl4 with the use of polyelectrolyte serve as reductant and stabilizer. At the same time, gold nanoparticles were observed self-assembly into dimer and trimer aggregates, which were evidenced by TEM. The nucleation and growth kinetics was characterized by in situ UV-vis experiment. A model was proposed to illustrate the formation mechanism.