Phase transition-driven modulation of ferroelectricity and the photovoltaic effect in sol–gel-derived BiFeO3-based films

Abstract

BiFeO₃ films have attracted much attention because of their high polarization and relatively narrow bandgap. However, major challenges such as low remanent polarization and photovoltaic output have hindered their practical applications and further development. Here, enhanced ferroelectric polarization and photocurrent in Pt/Bi_1−xPr_xFe_0.95Cr_0.05O₃/FTO devices were achieved by Pr and Cr co-doped BiFeO₃ films. X-ray diffraction (XRD) and Raman spectroscopy analyses indicate that Bi_1−xPr_xFe_0.95Cr_0.05O₃ films have a phase structure with coexisting rhombic (R3c) and tetragonal (P4mm) phases. By controlling the doping element content, dense and uniform films with few chemical defects were obtained. Notably, at the Pr doping level of 15%, a P_max of 137.1 μC cm⁻² and a P_r of 135.8 μC cm⁻² were achieved. The short-circuit current density (J_SC) and open-circuit voltage (V_OC) are −0.12 mA cm⁻² and 63.9 mV, respectively, under LED white light illumination. This work provides valuable information for the design and development of next-generation memory and photovoltaic devices.