ja8b13109_si_002.cif (257.59 kB)
Download fileFluoridation Achieved Antiperovskite Molecular Ferroelectric in [(CH3)2(F-CH2CH2)NH]3(CdCl3)(CdCl4)
dataset
posted on 2019-02-25, 00:00 authored by Zhong-Xia Wang, Yi Zhang, Yuan-Yuan Tang, Peng-Fei Li, Ren-Gen XiongAntiperovskites
have developed to be one kind of important functional
material over the past few decades, showing abundant physical properties
such as negative thermal expansion and superconductivity, etc. However, antiperovskite ferroelectrics have scarcely
been discovered in inorganic ceramics. In this article, we report
a new organic–inorganic hybrid antiperovskite ferroelectric
[(CH3)2(F-CH2CH2)NH]3(CdCl3)(CdCl4) based on the strategy
of molecular design. The replacement of one methyl in [(CH3)3NH]CdCl3 with ethyl produces the lower symmetric
[(CH3)2(CH2CH3)NH]CdCl3 with nonpolar perovskite structure, while the polar hexagonal
antiperovskite structure with the formula of X3BA (where
X = [(CH3)2(F-CH2CH2)NH]+, B = [CdCl3]−, and A = [CdCl4]2–) was received after further fluoridation
of the ethyl group. Therefore, fluoridation successfully achieves
the structural transformation from perovskite to antiperovskite, as
well as the significant changes in physical properties from nonferroelectric
to ferroelectric. The antiperovskite [(CH3)2(F-CH2CH2)NH]3(CdCl3)(CdCl4) exhibits typical ferroelectric phase transition above room
temperature (Tc = 333 K) including thermal
anomalies, dielectric transitions, and second harmonic generation
(SHG) responses. Moreover, lower coercive fields and easy polarization
switching are observed by the measurements of hysteresis loops and
ferroelectric domains. The saturated polarization (Ps) of 4.0 μC/cm2 is almost 10 times as
large as those recently discovered antiperovskite molecular ferroelectrics.
This finding provides a novel strategy to design and explore more
antiperovskite organic–inorganic hybrid ferroelectric materials.
