Controlled Growth of Silver Nanoparticle Seeds Using Green Solvents

A common method for producing silver nanoparticles (Ag NPs) is by chemical reduction of dissolved Ag⁺ with subsequent nucleation and growth of Ag(0). However, producing a monodisperse product with a controlled size can be a major challenge. Herein, we report results from a seeded Ag NP growth in a mixture of two green solvents, propylene carbonate (PC) and propylene glycol (PG). The solubility of AgCl in the mixed solvent is sufficiently high such that heterogeneous nucleation on AgCl can be prevented. In addition, results from varying the molar ratio of silver salt precursor to the Ag NP seeds enabled identification of an ideal range over which the homogeneous formation of new silver seeds can also be prevented. Preventing these two mechanisms is essential for the controlled and exclusive growth on the Ag NP seeds.