Synthesis of Positively Charged Luminescent CdTe Nanocrystals in Aqueous Solution

Highly luminescent positively charged CdTe nanocrystals were prepared from a facile and reproducible approach by the reaction of Cd2+ and HTe- in the presence of mercaptoethylamine. The influence of various experimental variables, including pH value, growth temperature, Te-to-Cd ratio, as well as Cd-to-ligand ratio, on the growth rate and optical properties of CdTe nanocrystals have been systematically investigated. Experimental results indicate that the pH value and Te-to-Cd molar ratio play the crucial role in determining luminescent properties of the obtained CdTe nanocrystals. The mechanism for the resulting high-quality optical properties of the resulting CdTe nanocrystals was also elucidated.