The Effects of Particle Concentration and Surface Charge on the Oriented Attachment Growth Kinetics of CdTe Nanocrystals in H2O

Crystal growth kinetics of thioglycolic acid (TGA)-capped CdTe nanoparticles in H2O was studied at different particle concentrations, with the aim to understand the effects of concentration and surface state of primary particles on the growth mechanism of nanocrystals. The growth process of CdTe nanoparticles was monitored by in situ UV–vis absorbance spectra, which reveal the coexisting growth mechanisms of oriented attachment (OA) and Ostwald ripening (OR). Increasing the primary nanoparticle concentration facilitated the OA-based growth at the initial stage, while the OR growth which was mainly occurring at the latter stage was restrained. On the basis of the fitting activation energy and experimental zeta potential, the effect of surface charge was further discussed and proved to be the critical factor that affected the OA process by directing the particle–particle interaction.