Enhancing Photovoltaic and Photosensing Performances in Bismuth Ferrite via Polar Order Engineering

Recent emerging developments have demonstrated that bismuth ferrite is one of the promising lead-free perovskite materials used in solar energy harvesting devices and photodetectors. This work reports high short-circuit photocurrent densities of ∼1.2 × 103 and ∼0.55 × 103 μA/cm2 in a p-type gadolinium-doped BiFeO3 ceramic with n-type indium tin oxide under 405 nm irradiation and sunlight at 102 mW/cm2 intensity, respectively. Polarization-enhanced photoresponsivity of ∼5.4 × 10–2 A/W and specific detectivity of ∼1.5 × 1011 Jones were achieved with response times of ∼1 and ∼10 ms, respectively, at the rising and decaying edges. Enhanced photovoltaic conversion via a prior electric-field poling can be attributed to the p–n junction and the field-modulated Schottky barrier in conjunction with domain nucleation, ordered polar nanoregions, and increased O 2p–Fe 3d orbital hybridization. The network of domain walls and grain boundaries serves as conduction pathways for the photogenerated charge carriers. The improved photocurrent in gadolinium-doped BiFeO3 opens up an opportunity for using bismuth ferrite materials in self-powered photodetectors.