Solution Synthesis of Monodisperse Indium Nanoparticles and Highly Faceted Indium Polyhedra

We report a simple and effective synthetic method to prepare monodisperse indium metal nanoparticles less than 10 nm in size via a simple lithium borohydride reduction method conducted in amine based solvents. The method has advantages over literature methods; in particular, use of highly reactive and costly organoindium precursors and small gold clusters is required for the heterogeneous growth of sub-10-nm indium nanoparticles. Highly monodisperse spherical nanoparticles produced in one pot in our system could be selectively passivated with commonly available surfactants, including oleylamine, trioctylphosphine and trioctylphosphine oxide. The amine solvents could be readily moved by evaporation under reduced pressure and the particles easily redispersed in common organic solvent in colloidal form. Additionally, highly faceted polyhedra of indium metal could also be produced under specific conditions.