The paper reports a novel mechanism for photovoltaic charge separation in ferroelectric materials, specifically in BiFeO$_3$ (BFO). Unlike conventional photovoltaics, which generate voltages up to the semiconductor's bandgap, this mechanism produces voltages significantly higher than the bandgap. The separation occurs at nanoscale domain walls in BFO, where the electric field is naturally present. This effect is reversible and controllable through electric field manipulation, allowing for the reversal of the photovoltaic polarity or turning off the effect. The study demonstrates that the photovoltage is linearly dependent on the number of domain walls and their width, with a potential drop per domain wall of about 10 mV. The mechanism involves the creation of a net charge imbalance near the domain walls due to the higher local electric field, leading to a significant voltage across the sample. The findings suggest potential applications in optoelectronic devices.The paper reports a novel mechanism for photovoltaic charge separation in ferroelectric materials, specifically in BiFeO$_3$ (BFO). Unlike conventional photovoltaics, which generate voltages up to the semiconductor's bandgap, this mechanism produces voltages significantly higher than the bandgap. The separation occurs at nanoscale domain walls in BFO, where the electric field is naturally present. This effect is reversible and controllable through electric field manipulation, allowing for the reversal of the photovoltaic polarity or turning off the effect. The study demonstrates that the photovoltage is linearly dependent on the number of domain walls and their width, with a potential drop per domain wall of about 10 mV. The mechanism involves the creation of a net charge imbalance near the domain walls due to the higher local electric field, leading to a significant voltage across the sample. The findings suggest potential applications in optoelectronic devices.