Self-Powered Photodetector Using Two-Dimensional Ferroelectric Dion–Jacobson Hybrid Perovskites

Dion–Jacobson (DJ) phase organic–inorganic
hybrid
perovskites (OIHPs) have emerged as promising alternatives to Ruddlesden–Poppers
perovskites because of their chemical stability and ferroelectric
phase. Here we fabricate a ferroelectricity-modulated photodetector
based on the n = 2 homologue of the ferroelectric
two-dimensional DJ-OIHP (AMP)­(MA)­Pb2I7 (DJPn=2, AMP = 4-(aminomethyl)­piperidinium; MA = methylammonium), which
shows an out-of-plane polarization and a saturated polarization (Ps) value of 3.7 μC/cm2. The
coercive field of DJPn=2 (0.34 kV/cm) is lower than that for the n = 1 homologue (AMP)­PbI4 (DJPn=1,0.4 kV/cm). DJPn=2 has a much longer carrier lifetime and absorption edge (580 nm,
2.13 eV) in comparison to DJPn=1 (523 nm, 2.37 eV); thus, DJPn=2 can be
used for efficient photodetection in the visible range, in which a
responsivity of 0.16 mA/W was achieved at 532 nm. The influence of
remnant polarization on the direction and magnitude of the photocurrent
was also demonstrated.