Effect of shells on photoluminescence of aqueous CdTe quantum dots

• CdTe quantum dots were fabricated using an aqueous synthesis.
• CdS, ZnS, and CdS/ZnS shells were subsequently deposited on CdTe cores.
• Outer ZnS shells provide an efficient confinement of electron and hole inside the QDs.
• Inside CdS shells can reduce the strain on the QDs.
• Aqueous CdTe/CdS/ZnS QDs exhibited high stability and photoluminescence efficiency of 80%.

CdTe cores with various sizes were fabricated in aqueous solutions. Inorganic shells including CdS, ZnS, and CdS/ZnS were subsequently deposited on the cores through a similar aqueous procedure to investigate the effect of shells on the photoluminescence properties of the cores. In the case of CdTe/CdS/ZnS quantum dots, the outer ZnS shell provides an efficient confinement of electron and hole wavefunctions inside the quantum dots, while the middle CdS shell sandwiched between the CdTe core and ZnS shell can be introduced to obviously reduce the strain on the quantum dots because the lattice parameters of CdS is situated at the intermediate-level between those of CdTe and ZnS. In comparison with CdTe/ZnS core–shell quantum dots, the as-prepared water-soluble CdTe/CdS/ZnS quantum dots in our case can exhibit high photochemical stability and photoluminescence efficiency up to 80% in an aqueous solution, which implies the promising applications in the field of biomedical labeling.

Size-tunable CdTe coated with several shells using an aqueous solution synthesis. CdTe/CdS/ZnS quantum dots exhibited high PL efficiency up to 80% which implies the promising applications for biomedical labeling.Figure optionsDownload as PowerPoint slide