Discovery of an Antiperovskite Ferroelectric in [(CH₃)₃NH]₃(MnBr₃)(MnBr₄)

Abstract

It is known that perovskites with the general chemical formula of ABX (A, B = cations, X = anion) have been intensively studied over the last half century because of their diverse functional properties, such as ferroelectricity in BaTiO, piezoelectricity in PZT (lead zirconate titanate), and recently developed photovoltaic properties in CHNHPbI. However, rather less attention has been paid to their "inverse" analogs, antiperovskites, which have a chemical formula XBA, where A and B are anions and X is a cation. Although most of important ferroelectrics are perovskites, no antiperovskite ferroelectrics have been found since the discovery of antiperovskites in 1930. Here, for the first time, we report a XBA antiperovskite ferroelectric [(CH)NH](MnBr)(MnBr) (where (CH)NH is X, MnBr is B, and MnBr is A), which shows outstanding ferroelectricity with a significantly high phase transition temperature of 458 K as well as fascinating photoluminescence properties with two intense emissions. This finding opens a new avenue to explore the golden area of antiperovskites for high-performance functional materials.

Unprecedented Dielectric Bistable Switching in a Binuclear HgII Based Hybrid Compound

“…To the best of our knowledge, such a promising contrast is unprecedented, despite the fact that extensive research has focused on the switchable dielectric behavior of most organic‐inorganic hybrid complexes . These advantages may represent a breakthrough in the search for fresh polycrystalline dielectric switches with such a fascinating high contrast …”

Halide Double Perovskite Ferroelectrics

“…This value is larger than some reported typical ferroelectrics, for instance, [(CH 3 ) 3 NH] 3 (MnBr 3 )(MnBr 4 ) (ca. 0.45 μC cm −2 ), Rochelle's salt (0.2 μC cm −2 ), and ammonium sulfate (0.25 μC cm −2 ), but slightly small than those of recently reported 2D lead‐based perovskite ferroelectrics (see Table S1). Figure S10 displays the variable‐temperature second harmonic generation (SHG) effects, revealing an obvious phase transition from a non‐centrosymmetric to a centrosymmetric state at about 222 K. Additionally, the polarization was determined by measuring of pyroelectric effects.…”

Halide Double Perovskite Ferroelectrics

“…This value is larger than some reported typical ferroelectrics, for instance, [(CH 3 ) 3 NH] 3 (MnBr 3 )(MnBr 4 ) (ca. 0.45 mC cm À2 ), [11] Rochelles salt (0.2 mC cm À2 ), and ammonium sulfate (0.25 mC cm À2 ), [12] but slightly small than those of recently reported 2D lead-based perovskite ferroelectrics (see Table S1). Figure S10 displays the variable-temperature second harmonic generation (SHG) effects, revealing an obvious phase transition from a non-centrosymmetric to a centrosymmetric state at about 222 K. Additionally, the polarization was determined by measuring of pyroelectric effects.…”