Synthesis and optical characterization of single phased ZnS:Mn²⁺/CdS core-shell nanoparticles.

Uncoated ZnS, ZnS:Mn(2+), CdS and different thickness of CdS coated ZnS:Mn(2+) core-shell nanoparticles were successfully synthesized by a simple chemical method in an air atmosphere. X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques were used to characterize the uncoated and the novel ZnS:Mn(2+)/CdS core-shell nanoparticles. The results show that the size of the ZnS:Mn(2+)/CdS core-shell nanoparticles is less than the bare ZnS:Mn(2+). The PL study of ZnS:Mn(2+)/CdS core-shell nanoparticles shows an enhanced intensity than ZnS:Mn(2+). The coating of CdS layer over ZnS:Mn(2+) tuned the PL emission in the visible region. Addition of cadmium acetate (Cd 4 and 5M) in ZnS:Mn(2+) shows a distinct PL peak centered at 542 nm. The presence of Mn(2+) ions in ZnS lattice and the growth of the CdS on ZnS:Mn(2+) nanoparticles were confirmed by the ESR spectra.