Discovery of an Above-Room-Temperature Antiferroelectric in Two-Dimensional Hybrid Perovskite

Antiferroelectric
materials have been regarded as a promising candidate
for electronic energy storage devices, due to their natural double
polarization versus electric field (P–E) hysteresis loops. Currently, two-dimensional organic–inorganic
hybrid perovskites with structural diversity and tunability, have
received blooming interests, whereas above-room-temperature antiferroelectrics
are still unreported in this perovskite system. Herein, for the first
time, we successfully acquire a two-dimensional Ruddlesden–Popper
hybrid perovskite antiferroelectric, ((CH3)2CHCH2NH3)2CsPb2Br7 (1), which shows an above-room-temperature Curie
temperature at 353 K, trigging by the synergistic dynamic motion of
inorganic Cs atoms and organic isobutylammonium cations. Intriguingly,
the antiferroelectricity of 1 existing over a wide temperature
range of 298–353 K are revealed by the distinct double P–E hysteresis loops. Besides, 1 possesses remarkable energy storage efficiency up to 69%,
comparable to those of some reported inorganic antiferroelectric ceramics,
promoting 1 potential application in energy storage devices.
This work provides an avenue to construct novel antiferroelectric
materials for high-performance electronic device applications.