Co-Doped ZnS Quantum Dots: Structural, Optical, Photoluminescence, Magnetic, and Photocatalytic Properties

Pristine and Co-doped ZnS quantum dots (QDs) were fabricated via a hydrothermal technique. Morphology studies showed that the fabricated QDs were nearly spheroidal with narrow size distribution. X-ray diffraction and Raman spectroscopy analyses demonstrated that the Co ions effectively penetrated the host matrix without changing its cubic phase. A minimal blue shift was found in the pristine ZnS QDs after doping with Co. The pristine and Co-doped samples exhibited similar blue emission, while increased (two times) photoluminescence intensity was observed for the Co-doped sample. X-ray photoelectron spectroscopy analysis showed trivalent Co ions in the ZnS lattice. The diamagnetic ZnS QDs were turned into ferromagnetic through Co-doping. The Co-doped ZnS QDs portrayed higher photocatalytic degradation (PCD) of Rhodamine B dye under artificial solar simulator irradiation than pristine ZnS. Hence, the Co-doped ZnS QDs may find applications in luminescent, spintronic and photocatalytic devices.