Abstract
This research describes the preparation of Co-doped ZnS Quantum Dots (QDs) with a high-reactivity colloidal method. Homogeneous nucleation occurred at the precursors' high-reactivity temperature, which is found dependent on the dopant concentration. Two compositions were studied: Zn0.095SCo0.005 and Zn0.091SCo0.009. The homogeneous nucleation occurred at 64 °C and 84 °C, respectively. Two schemes have been followed, temperature variation leading to an average QD size of 5.5 nm and aging routine, leading to a QD size of 5.0 nm. High-intensity emission spectral lines with a narrow linewidth that fell in the range of 1.4 nm–5 nm were observed. The purity of the created QD samples has been verified using elemental analysis. The X-ray diffraction (XRD) results of the crystal structure and high-resolution transmission electron microscopy (HRTEM) had shown coincidence. Doping ZnS QDs with cobalt reduced the FWHM from 3.67 nm to 1.40 nm. High emission intensities were observed at the most probable emission reported by the Co II's transition data.
•Zn0.1-xSCox QDs were prepared by the high-reactivity temperature colloidal method.•Narrow linewidth high-intensity emission has been obtained.•The QDs sizes have been tuned during temperature and timing stages.•Quantum confinement occurred with all dopant concentrations.•Resonance absorption and emission energies were observed.