Kinetics and Mechanisms of Aggregative Nanocrystal Growth

TLDR

The aggregative growth and oriented attachment of nanocrystals and nanoparticles are reviewed, contrasting them with classical LaMer nucleation and growth and Ostwald ripening, and aggregative growth is described as a nonclassical nucleation and growth process. Kinetic and mechanistic models are presented, including a nucleation function approximated by a Gaussian form whose height (Γmax) and width (Δtn) are systematically varied by conditions affecting the colloidal stability of primary nanocrystals. The nucleation parameters Γmax and Δtn correlate with the final nanocrystal mean size and size distribution, offering a potential means of achieving nucleation control in synthesis.

Abstract

The aggregative growth and oriented attachment of nanocrystals and nanoparticles are reviewed, and they are contrasted to classical LaMer nucleation and growth, and to Ostwald ripening. Kinetic and mechanistic models are presented, and experiments directly observing aggregative growth and oriented attachment are summarized. Aggregative growth is described as a nonclassical nucleation and growth process. The concept of a nucleation function is introduced, and approximated with a Gaussian form. The height (Γmax) and width (Δtn) of the nucleation function are systematically varied by conditions that influence the colloidal stability of the small, primary nanocrystals participating in aggregative growth. The nucleation parameters Γmax and Δtn correlate with the final nanocrystal mean size and size distribution, affording a potential means of achieving nucleation control in nanocrystal synthesis.