Effect of Mn doping on the structural, optical, magnetic properties, and antibacterial activity of ZnO nanospheres

This work investigates the systematic study of the structural, optical, magnetic, and antibacterial properties of Mn-doped ZnO. Zinc oxide (ZnO) and Mn²⁺ doped zinc oxide (ZnMnO) nanoparticles (NPs), were prepared through the co-precipitation method. The X-ray diffraction studies confirmed that the synthesized nanoparticles did not modify the crystal structure upon Mn doping. However, the microstructural parameters were changed considerably upon the increase of the concentration of Mn dopant. The HRTEM images showed that the ZnO NPs exhibit nanospheres-like morphology, and a reduction in the average particle size from 41 nm to 33 nm was observed upon Mn²⁺ doping. The elemental composition of Zn, Mn, and O atoms were identified by EDAX spectra. The Zn–O stretching bands were observed at around 550 cm⁻¹ in the FTIR spectra and the zinc and oxygen vacancies defects were confirmed by PL spectra. The estimated band gap of ZnO was 2.95 eV and increased to 3.14 eV for ZnMnO3. In addition, the Mn-doped ZnO NPs showed a more significant antibacterial effect than the pure ZnO NPs. The ZnO and Mn-doped ZnO NPs showed significant changes in the M-H loop where the diamagnetic behavior of ZnO changes to a weak ferromagnetic nature when doped with Mn ions. [Figure not available: see fulltext.]