Nucleation Control in the Aggregative Growth of Bismuth Nanocrystals

The kinetics and mechanism of Bi-nanocrystal growth from the precursor Bi[N(SiMe 3 ) 2 ] 3 are determined at various Na[N(SiMe 3 ) 2 ] additive concentrations. The results establish that aggregative nucleation and growth processes dominate Bi-nanocrystal formation. The time dependence of the aggregative nucleation rate−the nucleation function−is determined over the range of Na[N(SiMe 3 ) 2 ] concentrations studied. The time width of aggregative nucleation (Δ t n ) is shown to remain reasonably narrow, and to correlate with the final Bi-nanocrystal size distribution. The maximum aggregative nucleation rate (Γ max ) is shown to vary systematically with Na[N(SiMe 3 ) 2 ] concentration, producing a systematic variation in the final nanocrystal mean size. The Na[N(SiMe 3 ) 2 ] additive functions as both a nucleation-control agent and an Ostwald-ripening agent.