Study Of Structural And Optical Properties Of Copper, Manganese, And Mixed Metal (Cu And Mn) Oxide Nanoparticles

Background: Unique optical and electronic properties are exhibited by semiconductors in nanoparticle state as compared to their bulk form. Copper and manganese are transition metals which show various oxidation states and all the oxides have different characteristics as nanomaterials. These metal oxides have various applications in biosensing, photocatalysis, etc. Methods: For this work, pure copper and manganese oxide nanoparticles were synthesized via the Sol-Gel method. The same method was used to obtain mixed metal (Cu and Mn) oxide nanoparticles for three values of doping (5%, 10%, and 15%) of metallic Cu in manganese oxide and Mn in copper oxide. Results: X-Ray diffraction (XRD) patterns reveal that the monoclinic structure of pure CuO changes to tetragonal on doping it with Mn, whereas the cubic phase of manganese oxide is found to change to tetragonal and then to monoclinic as the doping level of Cu in it is increased. The surface texture of pure and mixed metal Scanning Electron Microscopy (SEM) has been used to study nanoparticles, and it has shown that as the doping level is raised, the nanoparticles' size and form vary noticeably. Additionally, the optical characteristics investigated by UV-Visible spectroscopy show that the energy band gap in the two cases strongly depends on the doping percentage. Conclusion: The crystallite size decreased from 30nm to 15nm after doping of Mn in CuO, whereas it increased from 17nm to 20nm after doping of Cu in MnO. The energy gap value changed from 1.34 eV to 1.77 eV for CuO and from 3.86 eV to 2.14 eV for MnO nanoparticles after doping.