Various Morphologies/Phases of Gold-Based Nanocomposite Particles Produced by Pulsed Laser Irradiation in Liquid Media: Insight in Physical Processes Involved in Particles Formation

In this work taking Au/M_xO_y (M = Fe, Co, Ni) particles as examples, we investigate and discuss the physical processes involved in particles formation by laser irradiation of mixture of two different kinds of nanoparticles dispersed in liquids. We showed that this method is an efficient and universal way for synthesis and control a variety of composite particles with various morphology (core-shell, alloy) and compositions which are not only metals or oxides but also nonequilibrium bimetallic alloys (AuFe, AuCo, and AuNi). Additionally, fluence diagrams which were designed to show the relation between laser fluence and particle diameter plot based on the heating-melting-evaporation model are useful for better understanding of the mechanism of composite particles formation during pulsed laser irradiation. To the extent of our knowledge, this is the first explanation of the mechanism of Au-based composite particles formation during pulsed laser irradiation of mixture of two different raw nanomaterials dispersed in liquid based on experimental results and theoretical calculations.