Acquiring Bulk Photovoltaic Effect in One-Dimensional Sn-Based Perovskite Single Crystals by Nonlinear Organic Diamine

Low-dimensional
metal halide perovskites with noncentrosymmetric
crystal structure provides opportunities of bulk photovoltaic effect
(BPVE), which is expected to promote efficiency of photovoltaic devices
by strengthening the build-in potential and carrier transport. Up
to now, perovskite materials with BPVE usually contain toxic lead
ions, which severely limits their practical application. Herein, one-dimensional
(1D) Sn-based perovskites MDASn2I6 (MDA = 4,4′-methylenedianiline)
with noncentrosymmetric structure by selecting an organic diamine
with nonlinear molecular configuration are reported. The directional
arrangement and inherent polarity of the MDA molecules endow the as-grown
1D single crystals with noncentrosymmetric crystal structure and spontaneous
polarization. Photodetectors with symmetrical electrodes show switchable
photovoltage and current–voltage curves, demonstrating the
existence of BPVE. Finally, the crystal properties under high pressure,
at which the crystals exhibit enhanced carrier transport and broader
absorption range, are investigated, showing the potential application
in extreme conditions. This work provides a novel strategy for the
design and preparation of noncentrosymmetric lead-free perovskite
single-crystal materials, which will promote green fabrication of
perovskite single-crystal optoelectronic devices.