Doping induced structural, band gap and photoluminescence properties of Cd0.9-xZn0.1CoxS nanoparticles

Co doped Cd0.9Zn0.1S (Co = 0-3 %) nanoparticles were prepared by a simple chemical co-precipitation method at room temperature. Optical and structural properties of the prepared samples have been studied using X-ray diffraction (XRD) and UV-visible spectrophotometer. XRD confirmed the cubic structure (phase singularity) of the samples and decline the secondary phase formation. Energy dispersive X-ray spectra showed the presence of Cd, Zn, Co and S in the appropriate proportion. Distortion produced by Co2+ in Cd-Zn-S made the lattice parameter of Co doped Cd0.9-xZn0.1S nanoparticles always higher than Cd0.9Zn0.1S. The reduced energy gap with Co substitution is mainly due to sp-d exchange interaction between the band electrons and the localized d electrons of the Co2+ ions substituting for host ions. The ultraviolet emission and visible band emission intensity and the modification in emission band position by Co-doping were discussed based on the size effect/change in structure and band gap. Based on the tailoring of energy gap and luminescence behavior, it can be concluded that Co-doped Cd0.9-xZn0.1S is a promising material for selective coatings for solar cells; use as antireflective coating materials, and for fabrication of optoelectronic devices.