Nanostructure formation via post growth of particles.

Post growth of particles will lead to new nanostructure formation, and blur the boundaries of crystal growth and molecular chemistry as well. The driving force of post growth usually stems from the inherent stabilities of the nanoparticles (NPs) and the environmental changes, which results in the transformation of the pristine nanostructures. One type of post growth driven by thermodynamic stability is Ostwald ripening, which usually leads to the elimination of small particles, and can be utilized to prepare hollow structures. By sophisticatedly controlling the reaction conditions, the NPs may undergo oriented attachment to form nanostructures with more complexity. This process is different from the random aggregation of nanoparticles; the final morphologies can be ingeniously controlled, and the kinetics resemble polymerization in some cases. If the chemical bonding during the oriented attachment process is replaced by non-covalent bonding, self-assembly of the NPs is achieved. Self-assembly of NPs further extends the diversity of nanostructures, as well as the understanding of crystallization. Post growth of particles is also a feasible strategy to fabricate heterostructures. The wetting behaviour sheds light on the final morphologies of the heterostructures. Meanwhile, seed mediated growth enables an alternative method to control pre-formed NPs. Another heterostructure of atomically-thin layered sheets connected via van der Waals forces also extends the potential of nanomaterials. The driving forces of the post growth of particles are divergent, and the applications are various. It can be utilized to prepare homogeneous and heterogeneous structures. [ABSTRACT FROM AUTHOR]