A facile low temperature growth of CdTe nanocrystals using novel dithiocarbamate ligands in aqueous solution

Proline dithiocarbamic acid disodium salt (ProDTC) was first explored as a novel ligand, instead of the usual used thiols, for the synthesis of CdTe nanocrystals (NCs). Due to the weak bonding between Cd ions and ProDTC, CdTe NCs show rapid nucleation and growth at much lower temperature (30-50 degrees C) compared to the traditional synthesis in an aqueous solution. Moreover, faster growth of ProDTCCdTe NCs under lower pH value was observed, while the thiol-CdTe system has an opposite tendency. The distinct growth kinetics is ascribed to the different complex constants between ProDTC-Cd and hiol-Cd, which has significant influence on the monomer activity. Although the photoluminescence quantum yield (PLQY) of as-prepared NCs was relatively low, it can be easily increased up to about 50% after further treatment of ligand exchange by replacing the surface-binding ProDTC molecules with the mercaptopropionic acid.