Lattice Monte Carlo Simulation of Cluster Coalescence Kinetics with Application to Template-Assisted Synthesis of Quantum Dots

Abstract

A Lattice Monte Carlo (LMC) simulation technique has been developed to describe the synthesis of a single semiconductor nanocrystal inside the droplets of a microemulsion. The LMC simulation can track the diffusion of a precursor, its irreversible reaction with a second precursor to form nuclei, and the diffusion and coalescence of the nuclei into clusters and eventually into a single particle. In this paper we compare two scenarios for forming a single nanocrystal. The first scenario involves very rapid (spontaneous) conversion of a precursor dispersed in the droplet to nuclei that diffuse and coalesce into a single particle. The second scenario involves diffusion of a precursor to the droplet interface where an irreversible reaction with a second precursor forms nuclei that subsequently diffuse into the droplet and coalesce. Simulations were performed describing the synthesis of ZnSe nanocrystals with diameters up to 7 nm, i.e., below the quantum confinement threshold of 9 nm for this material. Comparis...