We have measured the flexophotovoltaic effect of single crystals of halide perovskites ${\mathrm{MAPbBr}}_3$ and ${\mathrm{MAPbI}}_3$, as well as the benchmark oxide perovskite ${\mathrm{SrTiO}}_3$. For halide perovskites, the flexophotovoltaic effect is found to be orders of magnitude larger than for ${\mathrm{SrTiO}}_3$, and indeed large enough to induce photovoltages bigger than the band gap. Moreover, we find that in ${\mathrm{MAPbI}}_3$ the flexophotovoltaic effect is additional to a native bulk photovoltaic response that is switchable and ferroelectric-like. The results suggest that strain gradient engineering can be a powerful tool to modify the photovoltaic output even in already well-established photovoltaic materials.

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• Ferroelectricity
• Flexoelectricity
• Photocurrent