Role of Mn in biological, optical, and magnetic properties ZnO nano-particles

The properties of manganese-doped ZnO nano-particles fabricated by the sol-gel method were studied. The concentration of Mn in the ZnO was 1–4% w/w. The X-ray diffraction (XRD) confirmed wurtzite phase of ZnO. The results showed that Mn 2+ ions substituted Zn 2+ ions without altering the wurtzite structure of ZnO. Crystallite size was increased with increase in Mn doping percentage. Optical transmission recorded by UV–VIS–NIR spectrophotometer decreased with increase in Mn doping percentage. The optical band gap energy was quite low in the range 2.99–3.18 eV as compared to undoped ZnO and found to change with the increase in Mn percentage. Magnetic study displays that the Mn doped ZnO nanoparticles show ferro-magnetism at room temperature and the variation of the Mn percentage can tailor the ferromagnetic behavior of the nano-particles. Maximum coercivity of 228.07(Oe) is achieved for 2.5% Mn dopant and saturation magnetization is 0.03780 emu/g for 1.5% of Mn. Photo-catalytic activity was explored against methylene blue. 1% Mn contents have shown better photo-catalytic activity. It was discovered that ZnO nanoparticles with Mn doping displayed good antibacterial efficiency against Escherichia coli ( E. coli ) and Pseudomonas aeruginosa ( P. aeruginosa ) bacteria. The results displayed that the antibacterial activity of Mn doped ZnO nano-particles enhances with an increase in Mn percentage. Surface morphology is modified with an increase in Mn percentage. All thin films consist of nano-sized dispersed particles which are in agreement with the XRD results.