Photovoltaic effect induced by self-polarization in BiFeO₃ films

In this work, a significant visible-light photovoltaic effect is obtained under the influence of a built-in electric field in BiFeO₃ thin films. The photocurrent density, open-circuit voltage, and short-circuit current of the films are investigated systematically. For cells, the open-circuit voltage increases from 0.08 to 0.26 V after irradiation with light with a wavelength of 550 nm at a power density of 0.18 mW/nm. The photocurrent density at 550 nm reaches 1.8 × 10⁻⁷ A/cm², which is two orders higher compared to that of the dark state. The significant increase in these parameters is closely related to the separation and transport of photogenerated carriers driven by the built-in electric field. From the results, it is expected that this work can provide a method for improving the photoelectric performance of photovoltaic devices based on ferroelectric materials.