Preparation and Optical Properties of CdTe/CdO·nH2O Core/shell Nano-composites in Aqueous Solution

摘要

In this study, the deposition of CdO·nH2O on CdTe nanoparticles was studied in an aqueous phase. The CdTe nanocrystals (NCs) were prepared in aqueous solution through the reaction between Cd2+ and NaHTe in the presence of thioglycolic acid (TGA) as a stabilizer. The molar ratio of the Cd2+ to Te2- ions in the precursory solution played an important role in the photoluminescence of the ultimate CdTe NCs. The strongest photoluminescence was obtained under 4.0 of [Cd2+]/[Te2-] at pH～8.2. With the optimum dosage of cadmium (II) hydrous oxide deposited on the CdTe Ⅱ NCs, the photoluminescence was enhanced greatly. The photoluminescence of these nanocomposites was kept constant in the pH range of 8.0～10.0, but dramatically decreased with an obvious blue-shifted peak while the pH was below 8.0. In addition, the photochemical oxidation of CdTe NCs with cadmium hydrous oxide deposition was markedly inhibited.