Critical island-size, stability, and morphology of 2D colloidal Au nanoparticle islands

The critical island-size, stability, and morphology of 2D colloidal Au nanoparticle islands formed during drop-drying are studied using an empirical potential which takes into account core-core, ligand-ligand, and ligand-solvent interactions. Good agreement with experiment is obtained for the dependence of the critical island-size on nanoparticle diameter. Our results for the critical length-scale for smoothing via edge-diffusion are also consistent with the limited facet size and island-relaxation observed in experiments. In addition, the relatively high rate of monomer diffusion on an island as well as the low barrier for interlayer diffusion are consistent with experimental observations that second-layer growth does not occur until after the first layer is complete.