Evolution of ZnS Nanostructure Morphology under Interfacial Free-Energy Control

Under hydrothermal conditions and extremely high NaOH activity, ZnS forms nanostructures with complex morphologies that are based upon individual or interpenetrating nanosheets. Nanostructure morphology is independent of the size of the ZnS precursor (3 nm, 20 nm, or bulk) but varies systematically with NaOH concentration, producing compact microspheres, open nest- and flowerlike structures, and finally, individual nanosheets. The observations are consistent with a concept of nanostructure morphology controlled by a single parameter—the interfacial free energy of the ZnS (001) face. The synthesis of thermodynamically stable nanostructures open opportunities for new synthetic routes of materials with complex architectures.