Figure 6.

Proposed scheme for understanding the role of ultrasonic energy in the formation of gold nanoparticles. (a) Reduction of gold ions with sonication energy;, (b) growth of gold nanoparticles, (c) prevention or minimisation of wire-shaped gold cluster formation by breaking chain-like nanowires by ultrasonic waves, (d) monodispersed gold nanoparticles by ultrasonic waves with Oswald ripening or intra-particle ripening and (e) particle-particle fusion induced by excess of ultrasonic energy.