An Order–Disorder Type High‐Temperature Multiaxial Supramolecular Ferroelectric

Abstract

AbstractMuch progress has been witnessed in exploring host–guest type ferroelectrics represented by ammonium‐crown ether compounds. However, the major obstacles in expanding their promising applications in nonvolatile memory elements, capacitors, and sensors are relatively low Curie temperature (Tc) and uniaxial attribute. Herein, by screening different organic cations and inorganic anions to assemble with 18‐crown‐6 molecule, it is found that a new ammonium‐crown ether inclusion ferroelectric 1, [(ATHTP)(18‐crown‐6)]BF4 (ATHTP = protonated 4‐aminotetrahydrothiopyran), undergoing a ferroelectric phase transition at a much higher Tc of 392 K which is comparable to BaTiO3 (Tc = 393 K). Notably, the distinct symmetry breaking, that is, 4/mmmFmm2, leads to a biaxial ferroelectric with four equivalent directions of polarization. Such high Tc and multiaxial nature are rare in existing crown ether‐based ferroelectrics. This work can help the exploration of high‐Tc multiaxial ferroelectrics toward further device applications.