Doped and undoped ZnS colloidal nanocrystals have drawn much attention due to their versatile applications in the fields of optoelectronics and biotechnology. In this paper, Cu doped ZnS quantum dots were synthesized via the simple thermolysis of ethylxanthate salts. The lattice and
optical properties of the nanocrystals were then studied in detail. The quantum dot lattice contracted linearly between Cu concentrations of 0.2–2%, while it continued to contract more gradually as Cu concentrations were further increased from 4 to 6%, due in part to the Cu ions located
on the surface of the ZnS lattice. Cu incorporation induces a long tail in absorption at long wavelengths. The PL spectrum shows a red shift at first, and then a blue shift with increases in Cu concentration. Cu doped at low concentrations (0.2–1%) enhanced the emission, while high Cu
concentrations (2–6%) quenched emissions.
Red-shift of the photoluminescent emission peaks of CdTe quantum dots due to the synergistic interaction with carbon quantum dot mixtures
