Precise Molecular Design Toward Organic-Inorganic Zinc Chloride ABX3 Ferroelectrics

Organic-inorganic ABX(3) (A, B = cations, X = anion) hybrids with perovskite structure have recently attracted tremendous interest due to their structural tunability and rich functional properties, such as ferroelectricity. However, ABX(3) hybrid ferroelectrics with other structures have rarely been reported. Here, we successfully designed an ABX(3) hybrid ferroelectric [(CH3)(3)NCH2F]ZnCl3 with a spontaneous polarization of 4.8 mu C/cm(2) by the molecular modification of [(CH3)(4)N]-ZnCl3 through hydrogen/halogen substitution. It is the first zinc halide ABX(3) ferroelectric, which contains one-dimensional [ZnCl3](n)(-) chains of corner-sharing ZnCl4 tetrahedra, distinct from the anionic framework of corner-sharing or face-sharing BX6 octahedra in the ABX(3) perovskites. From zero dimension to one dimension, the high symmetry of ZnCl4 tetrahedra is broken, and all of them align along one direction to form a polar [ZnCl3](n)(-) chain, beneficial to the generation of ferroelectricity. This finding provides an efficient polar anionic framework for enriching the family of hybrid ferroelectrics by assembling with various cations and should inspire further exploration of new classes of organic-inorganic ABX(3) ferroelectrics.