Self-organization of cadmium sulfide nanoparticles on the macroscopic scale

A self-organization of chemical bath deposited cadmium sulfide colloidal particles into well shaped hexagonal prisms of nearly the same size in a micrometer range is found. The selforganization phenomenon itself and the size of resulting prisms depend on the chemical affinity of the deposition reaction. In spite of the nearly perfect shape, the inner structure of the CdS colloidal crystals is highly disordered and has at least two hierarchy levels. On the scale of scanning electron microscopy, the loose and disordered microstructure of the colloidal crystals consists of nonuniformly shaped coagulates, with sizes between 150 and 250 nm. Transmission electron microscopy shows that the coagulates are polycrystals with large angle boundaries between nonuniformly shaped grains with an average size of 7 ± 2 nm.