Crystallite size controlled doping of transition metals (Co, Cu) in ZnO nanocrystals to investigate microstructural, optical, magnetic, and photocatalytic properties

Abstract

In this report, Co and Cu doped ZnO nanocrystals with controlled crystallite size were synthesized. The formation of the hexagonal wurtzite phase is confirmed by Rietveld refinement of X-ray diffraction (XRD) patterns. Crystallite size ranges (17 nm–20 nm) obtained from XRD analysis are complemented with transmission electron microscopy (TEM) observation. The presence of E2high mode recognized the unchanged phase and good crystalline nature of the nanocrystals. Photoluminescence (PL) spectra of Co and Cu doped ZnO nanocrystals are related to zinc and oxygen based defect states. The quenching of PL intensity is due to the incorporation of Co and Cu in the ZnO nanocrystals. ESR results complement the decrease in ferromagnetic order as obtained by VSM measurement in both Co and Cu doped ZnO nanocrystals. The superior photocatalytic activity of Cu doped ZnO nanocrystals could be due to the higher electron trapping capability of Cu2+ ions.