Enhanced Photovoltaic and Photosensing Performances in Gadolinium-Doped Bismuth Ferrite

Recent emerging developments have demonstrated that bismuth ferrite is one of the promising lead-free perovskite materials for solar-energy harvesting, photoelectrochemical conversion, and photodetector. This work reports high short-circuit photocurrent densities ~1.2×1033 µA/cm2 in p-type gadolinium (Gd)-doped BiFeO3 ceramic with n-type indium-tin-oxide under 405 nm irradiation and sunlight at 102 mW/cm2 intensity, respectively. A polarization-enhanced photosensing responsivity (R) of ~5.4×10-2 A/W and detectivity (D*) of ~1.5×1011 Jones were achieved at low 405 nm irradiation. Enhanced photovoltaic conversion via a prior electric-field poling can be attributed to the p-n junction and field-modulated Schottky barrier in conjunction with domain nucleation, ordered polar nano-regions (PNRs), and increased O 2p-Fe 3d orbital hybridization. The network of domain walls and grain boundaries serves as conduction pathways for the photo-generated charge carriers. The remarkable improvement of photocurrent in polycrystalline Gd-doped BiFeO3 opens a window for using bismuth ferrite materials in self-powered UV-visible photodetector.