Modulated photovoltaic response in a flexoelectric device using microscopic indentation

The use of ferroelectric materials in photovoltaics has garnered significant attention due to the presence of a giant open circuit voltage response. In addition, while flexoelectric effects are known to contribute to the magnitude and direction of internal electric fields, they have yet to be exploited in a controllable and permanent way in devices. In this study, we employ microscopic indentation in photovoltaic capacitor devices based on an archetypal ferroelectric material, that is, BaTiO3. Our findings reveal that the applied indentation force can modulate the internal electric fields via flexoelectric effects. However, this comes with increased device conductivity, which indicates the unavoidable presence of an increased number of defects. Importantly, this modulation is accompanied by a tunable photovoltaic response. These results suggest that indentation offers a novel approach to engineer devices with an enhanced photoresponse.