All oxide lead-free bismuth ferrite perovskite absorber based FTO/ZnO/BiFeO3/Au solar cell with efficiency ∼ 12%: First principle material and macroscopic device simulation studies

Abstract

We report the photovoltaic response of bismuth ferrite (BiFeO3) multiferroic absorber based all oxide FTO/ZnO/BiFeO3/Au solar cell using density functional theory for materials optoelectronic properties and macroscopic device simulation-based hybrid approach. The structural, electronic, and optical properties of BiFeO3 are investigated using density functional theory (DFT). The band structure and density of states of R3c-BiFeO3 are computed considering the Hubbard parameter Ueff∼4.2eV for both Fe-3d and O-2p orbitals for matching the experimental bandgap of ∼2.5eV. The computed optical properties, such as absorption for rhombohedral R3c-BiFeO3, are used to investigate FTO/ZnO/BiFeO3/Au solar cell performance using a macroscopic device simulation approach. The thickness, acceptor concentration, defect concentration of the absorber layer, interface defect density, electron affinity of the electron transport layer, and the impact of series, shunt resistance, and metal back contact are investigated to optimize the photovoltaic response under realistic conditions. The optimum photoconversion efficiency (PCE) is ∼11.92% with open circuit voltage (Voc) of 1.033V, short circuit current density (Jsc) of 15.27mA/cm2, and fill factor (FF) of 75.59%. This study on BiFeO3-based absorber materials opens a way to realize lead-free perovskite absorber material with a potential for realizing all oxide solar cells.