Digestive ripening, nanophase segregation and superlattice formation in gold nanocrystal colloids

A novel digestive ripening process is shown to narrow the particle size distribution from a highly polydisperse dodecanethiol ligated gold colloid. Unlike the Ostwald ripening process, the digestion occurs through transferring materials from large particles to small particles. Temperature-induced size segregation can further select the particle sizes. By using these two methods, highly ordered superlattices using nanocrystals as building blocks can be synthesized directly from a polydisperse colloid.