Preparation and Characterization of Ni-Doped Zns Nanoparticles for Diffuse Reflectance

Abstract

ZnS nanoparticles doped with Ni were successfully synthesized by chemical precipitation method. The influence of various reaction conditions and dopant concentrations on the formation, phase, morphology and diffuse reflectance of NPs have been investigated and discussed. XRD studies clearly showed the formation of zinc blende phase of ZnS and also confirm that Ni atoms are not incorporated into the lattice of ZnS as no impurity peak of Ni was found. But broadening in the diffraction peaks with different molar concentrations of Ni suggests the presence of Ni on the surface of ZnS. The average crystallite size decreases as the concentration of dopant was increased. TEM micrograph showed the uniformity in shape of synthesized nanoparticles. From the absorption spectra the band gap of the NPs was calculated and found to be higher than that of the bulk counterpart. Also, UV-visible studies showed that band gap of ZnS increases as the concentration of dopant increases. The luminescence property of the NPs was studied by the emission spectrum, which confirms the presence of defect levels caused by the S2- vacancies. PL studies showed that Ni acts as electron trapping center, which results into nonradiative recombination thereby decreasing the luminescent intensity due to S2-. From the reflectance spectra of NPs diffuse reflectance comes out to be 92-98% in the visible region.