Shi Zhifang, Fang Zheng, Wu Jingshu, Chen Yi, Mi Qixi
School of Physical Science and Technology, ShanghaiTech University, Shanghai, China.
Nat Commun. 2021 Jun 10;12(1):3548. doi: 10.1038/s41467-021-23917-z.
The structure and properties of organic-inorganic hybrid perovskites are impacted by the order-disorder transition, whose driving forces from the organic cation and the inorganic framework cannot easily be disentangled. Herein, we report the design, synthesis and properties of a cage-in-framework perovskite AthMn(N), where Ath is an organic cation 4-azatricyclo[2.2.1.0]heptanium. Ath features a rigid and spheroidal profile, such that its molecular reorientation does not alter the cubic lattice symmetry of the Mn(N) host framework. This order-disorder transition is well characterized by NMR, crystallography, and calorimetry, and associated with the realignment of Ath dipole from antiferroelectric to paraelectric. As a result, an abrupt rise in the dielectric constant was observed during the transition. Our work introduces a family of perovskite structures and provides direct insights to the order-disorder transition of hybrid materials.
有机-无机杂化钙钛矿的结构和性质受到有序-无序转变的影响，而来自有机阳离子和无机骨架的驱动力不易区分。在此，我们报告了一种骨架内嵌笼状钙钛矿AthMn(N)的设计、合成及性质，其中Ath是有机阳离子4-氮杂三环[2.2.1.0]庚烷鎓。Ath具有刚性且呈球状外形，因此其分子重排不会改变Mn(N)主体骨架的立方晶格对称性。通过核磁共振、晶体学和量热法对这种有序-无序转变进行了很好的表征，并且该转变与Ath偶极从反铁电体到顺电体的重新排列有关。结果，在转变过程中观察到介电常数急剧上升。我们的工作引入了一类钙钛矿结构，并为杂化材料的有序-无序转变提供了直接的见解。
