Transition metal (Co, Mn) co-doped ZnO nanoparticles: Effect on structural and optical properties

Pure ZnO and Co/Mn co-doped ZnO {Zn0.98-xCo0.02MnxO (0 ≤ x ≤ 0.06)} nanoparticles were synthesized by co-precipitation method. The structural, morphological and optical properties of prepared samples were explored in detail. Rietveld refinement of x-ray diffraction (XRD) data revealed the single phase, hexagonal wurtzite structure without any impurity phase. XRD and Fourier transform infra-red (FTIR) analysis confirmed the incorporation of Co/Mn ions at Zn site into host lattice structure. The morphology of samples was examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis. The particle size from TEM results was corroborated well with XRD data. The absorption spectra showed the initial decrease in optical energy band gap for low Mn concentration. The optical energy band gap further increased with a higher Mn concentration in co-doped ZnO samples. Photoluminescence (PL) spectra showed five emission peaks due to different defect states. The paper enhances the understanding of structural, optical properties of Co/Mn co-doped nanocrystals. This paves the path for its potential application in the optoelectronic devices e.g. solar cell. [Display omitted] •Pure and Co-Mn doped ZnO nanocrystals were synthesized by co-precipitation route.•Structural, morphological and optical properties of samples have been studied.•Oxygen related defect states are reduced with increasing doping concentrations.•Co-Mn doped ZnO samples are promising material for application in solar cells.