Crystalline Nanoflowers with Different Chemical Compositions and Physical Properties Grown by Limited Ligand Protection

摘要

Colloidal nanocrystals with controlled size and shape play a key role in nanotechnology.[1]-[3] Organometallic[4]-[6] and related alternative (or so-called greener)[7]-[10] synthetic methods at elevated temperatures in non-aqueous solvents are the current mainstream strategies for producing high-quality nanocrystals. The ability to control the size and size distribution of nanodots using these strategies is reasonably well developed. Also, advances in the formation of 1D nanocrystals have recently been reported.[5], [11]-[14] These 1D structures offer a unique technical potential that is inaccessible with the corresponding 0D nanocrystals. Reports on the synthesis of complex 3D nanostructures, however, remain uncommon.[15]-[19] Most of these structures are grown on substrates, are large in size, and/or are polycrystalline. Herein, we demonstrate that, by simply reducing the degree of ligand protection to the domain of limited ligand protection (LLP), the existing mainstream synthetic chemistry for 0D and 1D nanocrystals - more specifically, the greener approaches - can also produce high-quality complex 3D nanostructures, such as crystalline nanoflowers. Unlike the formation of tetrapods of II-VI semiconductors with specific crystal structures,[15], [20] we reveal that LLP coupled with 3D oriented attachment can be applied in the preparation of nanocrystals with different compositions, crystal structures, and physical (magnetic and electronic) properties.