Bandgap tuning of Mn-doped of BiFeO3 thin films for Photovoltaic Application

Mn-doped BiFeO3 (BFO) thin films were prepared on glass substrates using a simple spin coating method, and their structural and optical properties were analyzed. The X-ray diffraction pattern of Mn-doped BFO confirmed the presence of rhombohedral distorted perovskite structure, while FTIR analysis detected the Bi-O and Fe-O bonds in the perovskite structure. The XPS spectra of the Mn-doped BFO thin film provided information on the valence states of Bi, Fe, and Mn based on their respective binding energies. The UV-visible-NIR spectra revealed that the optical band gap of the pristine BFO was 2.17 eV, while that of Mn-doped BFO was 1.65 eV, which is optimum for solar cell absorber layer applications. The decreasing pattern suggests effective Mn doping of BFO.