Enhanced orange emission of Zn0.98-XMn0.02CoxS (x=0≤0.02) quantum dots

Mn (2+), Co2+ ions double doped ZnS was obtained via co-precipitation technique under room temperature. The doping concentration of Mn2+ was fixed as 2 at. wt% and Co2+ was varied from 0 to 3%. The synthesized products were analyzed using XRD, SEM, EDX, UV-vis optical study, FT-IR spectra and PL spectra. The synthesized nanostructures size was determined from XRD results and they were in the range of 2.9 to 3.7 nm and the size was increased for Co2+ 1 at. wt% doping. All the samples had a cubic structure without a trace of any secondary phases. The optical band gap values are red-shifted due to the increase of Co2+ concentration. A higher UV-vis optical transmittance was offered by 1 at. wt% Co2+ doped Mn:ZnS nanostructures. PL emissions noticed at 472 and 592 nm. These blue and orange emissions were addressed by the creation of trap states due to the incorporation of Co2+ ions and the emission intensity was increased at higher composition of dopant. The creation of more charge carriers and the generation of defects are responsible for the improved catalytic behavior in Co = 2% doped Zn0.98Mn0.02S which established superior efficiency after sex recycling progression.