Modulating the magnetic-optical properties of Zn1−xCoxO nanocrystals with x-content

In this study, magnetic-optical properties of Zn 1− x Co x O NCs were modulated with x -content. The optical, structural, morphological, and magnetic properties were investigated by optical absorption (OA), fluorescence (FL), X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and electronic paramagnetic resonance (EPR). The XRD and Raman results confirm the growth of Zn 1− x Co x O NCs, with x greater than 1.0 having occurred for the formation of the nanocomposite (Co-doped ZnO/ZnCo 2 O 4 ). The formation of the nanocomposite allows new and exciting optical and magnetic properties. SEM images show inhibition in ZnO nanorod growth with Co-content and formation of ZnCo 2 O 4 NCs. OA and FL spectra have changed with x -content in Zn 1− x Co x O NCs. These changes are strongly related to the symmetric environment of the Co 2+ ions within ZnO NCs and the formation of ZnCo 2 O 4 NCs. A linear dependence of FL intensity was observed with the x-content in the red-green region. The symmetric environment and the nanocomposite formation also alter the magnetic properties confirmed by EPR. Therefore, Zn 1− x Co x O NCs can be a material platform suitable for photonic devices, magnetic-optical devices, or spintronics. Graphic abstract