Chen Lizhuang, Liao Wei-Qiang, Ai Yong, Li Junyi, Deng Siyu, Hou Yunlong, Tang Yuan-Yuan
School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, People's Republic of China.
Ordered Matter Science Research Center, Nanchang University, Nanchang 330031, People's Republic of China.
J Am Chem Soc. 2020 Apr 1;142(13):6236-6243. doi: 10.1021/jacs.0c00315. Epub 2020 Mar 18.
Organic-inorganic ABX (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 hybrid ferroelectrics with other structures have rarely been reported. Here, we successfully designed an ABX hybrid ferroelectric [(CH)NCHF]ZnCl with a spontaneous polarization of 4.8 μC/cm by the molecular modification of [(CH)N]ZnCl through hydrogen/halogen substitution. It is the first zinc halide ABX ferroelectric, which contains one-dimensional [ZnCl] chains of corner-sharing ZnCl tetrahedra, distinct from the anionic framework of corner-sharing or face-sharing BX octahedra in the ABX perovskites. From zero dimension to one dimension, the high symmetry of ZnCl tetrahedra is broken, and all of them align along one direction to form a polar [ZnCl] 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 ferroelectrics.
具有钙钛矿结构的有机-无机ABX（A、B为阳离子，X为阴离子）杂化物由于其结构可调性和丰富的功能特性，如铁电性，最近引起了极大的关注。然而，具有其他结构的ABX杂化铁电体鲜有报道。在此，我们通过氢/卤素取代对[(CH)N]ZnCl进行分子修饰，成功设计出一种自发极化强度为4.8 μC/cm的ABX杂化铁电体[(CH)NCHF]ZnCl。它是首个卤化锌ABX铁电体，包含由共角的ZnCl四面体构成的一维[ZnCl]链，这与ABX钙钛矿中由共角或共面的BX八面体构成的阴离子骨架不同。从零维到一维，ZnCl四面体高对称性被打破，它们全部沿一个方向排列形成极性[ZnCl]链，有利于铁电性的产生。这一发现为通过与各种阳离子组装来丰富杂化铁电体家族提供了一种有效的极性阴离子骨架，并应能激发对新型有机-无机ABX铁电体的进一步探索。
