Oriented attachment crystal growth kinetics and its roles in tailoring optical properties of quantum dots

Abstract

In-depth understandings of crystal growth mechanisms and kinetics provide guidance to tune the crystal growth and thus to achieve new types of nanostructures and new material properties. The common mechanisms to describe crystal growth is based on the Ostwald ripening (OR) theory and the newly discovered oriented attachment (OA) mechanism. The OR kinetics are characterized by the growth of larger particles at the expense of smaller particles. In OA mechanism, two common crystallographically oriented nanoparticles combine together to form a larger one. Recently, increasing attention is being paid to the role of OA in the formation of specific microstructure or self-assembly of nanomaterials. However, the majority of research is restricted to the investigation of the growth process itself rather than to get comprehensive insights of the kinetics and the underlying mechanism in particular. In this context, we review the progress of the OA mechanism and its important significance on materials science. Progress on the OA kinetic models was systematically summarized, showing the kinetic rules of size, morphology, and lattice structure of nanocrystals in OA or complexed OR+OA mechanism. The surface adsorption were proved to be an effective factor for arresting the OR process and facilitating the exclusive OA growth stage. The conrol mechanism of surface ligand on OR and OA were anaylzed thoroughly. Based on the above knowledge, attempts will be made to shed light on the relationship between the photoluminescence (PL) evolution rule of nanocrystal and the growth mechanism/kinetics of nanocrystals. We anticipate this work could provide the fundamental understanding for introducing the surface adsorption to tune the crystals growth of semiconductor nanocrystals, thus to tailor and achieve preparing QDs with desired PL properties.