Growth Kinetics of Aqueous CdTe Nanocrystals in the Presence of Simple Amines

In this paper, simple amines, such as ammonia (NH3) and hydrazine (N2H4), were deliberately added to the growing system of aqueous CdTe nanocrystals (NCs) to promote their growth at room temperature. Systematical investigations revealed that NC growth was the combination of kinetics-favored agglomeration growth and thermodynamics-favored diffusion equilibrium (or decomposition). On one hand, the rapid growth of NCs in the presence of amines was mainly an agglomeration growth. Simple amines were weak electrolytes, the presence of which greatly weakened the interparticle electrostatic repulsion. Accordingly, the adsorption and fusion of NC monomers and/or clusters were facilitated, leading to a rapid agglomeration growth of NCs. On the other hand, the growth rate and process of NCs also depended on pH, species of mercapto-ligands, and especially species and concentrations of amines. These indicated that the evolution of NCs also related to the activity of Cd and/or Te monomers in solution, which was thermod...