Simulation Study of Self-Assembly of Polydisperse Nanoparticles Into Highly Uniform Aggregates

We investigate the self-assembly of highly polydisperse inorganic nanoparticles (CdSe, CdS, ZnSe and PbS) into highly uniform supraparticles with a core-shell morphology. The self-assembly process is believed to be self-limiting due to the balance between van der Waals attraction and Coulombic repulsion as observed in experiments and further elaborated by our simulations. The uniform supraparticles are shown to be thermodynamically stable states. Our results also reveal that it is the considerable polydispersity of the nanoparticles that results in the core-shell morphology of the supraparticles. The generic nature of the governing interactions suggests great versatility in the composition, size and shape of the constituent building blocks, and allows for a large family of self-assembled structures, including colloidal crystals.