Ferroelectric materials are interesting candidates for future photovoltaic applications due to their potential to overcome the fundamental limits of conventional single bandgap semiconductor-based solar cells. Although a more efficient charge separation and above bandgap photovoltages are advantageous in these materials, tailoring their photovoltaic response using ferroelectric functionalities remains puzzling. Here we address this issue by reporting a clear hysteretic character of the photovoltaic effect as a function of electric field and its dependence on the poling history. Furthermore, we obtain insight into light induced nonequilibrium charge carrier dynamics in Bi2FeCrO6 films involving not only charge generation, but also recombination processes. At the ferroelectric remanence, light is able to electrically depolarize the films with remanent and transient effects as evidenced by electrical and piezoresponse force microscopy (PFM) measurements. The hysteretic nature of the photovoltaic response and its nonlinear character at larger light intensities can be used to optimize the photovoltaic performance of future ferroelectric-based solar cells.

Ferroelectric materials are an alternative to semiconductor-based photovoltaics and offer the advantage of above bandgap photovoltage generation. However, there are few known compounds, and photovoltaic efficiencies remain low. Here, we report the discovery of a photovoltaic effect in undoped lead magnesium niobate-lead titanate crystal and a significant improvement in the photovoltaic response under suitable electric fields and temperatures. The photovoltaic effect is maximum near the electric-field-driven ferroelectric dipole reorientation, and increases threefold near the Curie temperature (T c ). Moreover, at ferroelectric saturation, the photovoltaic response exhibits clear remanent and transient effects. The transient-remanent combinations together with electric and thermal tuning possibilities indicate photoferroelectric crystals as emerging elements for photovoltaics and optoelectronics, relevant to all-optical information storage and beyond. DOI: 10.1103/PhysRevMaterials.2.012401 Photoferroelectrics are remarkable materials that have great potential for multifunctional applications [1]. These materials that exhibit (multi)ferroic order are particularly interesting, because they offer advanced electric operation that is related to multiple electric polarization switching states [2]. The field was rejuvenated after the discovery of the photovoltaic effect in the multiferroic BiFeO 3 [3,4], resulting in the revival of ferroelectric-based photovoltaic operation and related materials [5][6][7][8]. Based on recent progress in photovoltaic efficiency of Bi 2 FeCrO 6 films [9], ferroelectric (FE) cells might become competitors for conventional photovoltaics in the near future. In this respect, better insight into photoinduced changes of electrical properties over a wide range of temperatures and electric fields would be helpful. Such a study, however, requires high-quality crystals that are free from the surface/interface effects occurring in thin films [10] and the grain size dependence occurring in ceramics [11]. This task is challenging because the total number of currently known photovoltaicferroelectric compounds is well below 20 [5][6][7][8] We also detail the remanent photopolarization properties originating from the photocarrier generation-distribution mechanism, and demonstrate how the photovoltaic response can be tuned by varying the applied electric field and temperature.The crystals had (001) orientation, and were square shaped with edges along the [010] and [100] directions [ Fig. 1(a)]. In-* Corresponding author: kundysATipcms.unistra.fr dependent energy-dispersive x-ray spectroscopy (EDS) analysis confirmed the PMN-32%PT composition of the crystal. The sample's dimensions were 901 μm × 272 μm × 2161 μm, and both electrodes were formed with silver paste covering the edges in the planes parallel to yz [ Fig. 1(a)]. This experimental geometry was chosen to minimize light power loss and to avoid possible extrinsic contributions related to light-assisted charge injection from electrodes. The hyster...