  Ferroelectric photovoltaic 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. 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.
