Photovoltaic conversion and quantum efficiency in perovskite multiferroic ceramics

Abstract

Junction-driven photovoltaic effects in lead-free perovskite BiFeO3 multiferroic materials have demonstrated promising applications in energy harvesting and optical sensors. This study highlights remarkable photon-to-electron external quantum efficiency (EQE) of ∼9% and light-to-electric power-conversion efficiency (PCE) of ∼0.8% in the heterostructure consisting of A-site neodymium-doped BiFeO3 ceramic and indium-tin-oxide (ITO) thin film under irradiation of wavelength λ = 405 nm. A theoretical p-n-junction model based on the photo-generated carriers was employed to quantitatively describe open-circuit voltage (Voc) and short-circuit current density (Jsc) as functions of irradiation intensity, and to calculate junction widths and carrier densities. The direct band gap and the degree of local disorder (or defect state) were estimated using the photon-energy-dependent optical attenuation coefficient with the Tauc and Urbach relations.