Shape-controlled growth of metal nanoparticles: an atomistic view

Official URL: http://dx.doi.org/10.1039/C5CP03902A

Recent developments in shape-controlled synthesis of metallic nano-particles present a promising path for precisely tuning chemical activity, selectivity, and stability of nano-materials. While previous studies have highlighted the macroscopic description of synthesis processes, there is less understanding as to whether individual atomic-scale processes posses any signicant role in controlling growth of nano-products. The presented molecular static and dynamic simulations are the rst simulations to understand the underlying atomistic mechanisms of the experimentally determined growth modes of metal nano-clusters. Our simulations on Ag nano-cubes conrm that metal nano-seeds enclosed by {100} facets can be directed to grow into octopod, concave, truncated cube, and cuboctahedron when the relative surface diusion and deposition rates are nely tuned. Here we further showed that atomic level processes play a signicant role in controllably ne tuning the two competing rates: surface diusion and deposition. We also found that regardless of temperature and initial shape of the nano-seeds, the exchange of the deposited atom with an edge atom of the seed is by far the governing diusion mechanism between the neighboring facets, and thus is the leading atomistic process determining the conditions for ne tuning of macroscopic processes.