  Inorganic ferroelectric perovskite oxides are more stable than hybrid
perovskites. However, their solar energy harvest efficiency is not so good.
Here, by constructing a series of BiFeO3 based devices (solar cells), we
investigated three factors that influence the photovoltaic performance,
including spontaneous polarization, terminated ions species in the interface
between BiFeO3 and the electrode, and polarized light irradiation. This work
was carried out in the framework of density functional theory combined with
non-equilibrium Green's function theory under built in electric field or finite
bias. The results showed that 1. the photocurrent is larger only under a
suitable electronic band gap rather than larger spontaneous polarization; 2.
the photocurrent reaches the largest in Bi ions terminated interface than in
the case of Fe ion or O ion with SrTiO3 electrode; 3. the photocurrent could be
largely enhanced if the polarized direction of the monochromatic light is
perpendicular to the spontaneous polarization direction. The results would
deepen the understanding of some experimental results of BiFeO3 based solar
cells.
