Zeng Yu-Ling, Huang Xue-Qin, Huang Chao-Ran, Zhang Hua, Wang Fang, Wang Zhong-Xia
Ordered Matter Science Research Center, Nanchang University, Nanchang, 330031, P. R. China.
Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, College of Chemistry and Chemical Engineering, Gannan Normal University, Ganzhou, 341000, P. R. China.
Angew Chem Int Ed Engl. 2021 May 3;60(19):10730-10735. doi: 10.1002/anie.202102195. Epub 2021 Mar 30.
Chiral perovskites have emerged as a significant class of materials showing promising optoelectronic and spintronic applications. Reports of chiral perovskite ferroelectrics, however, have been scarce. In this work, we have successfully synthesized homochiral lead-iodide perovskite ferroelectrics [(R)-N-(1-phenylethyl)ethane-1,2-diaminium]PbI and [(S)-N-(1-phenylethyl)ethane-1,2-diaminium]PbI by introducing a methyl group into the organic cation of the parent (N-benzylethane-1,2-diaminium)PbI . Vibrational circular dichroism spectra identify the chiral mirroring relationship. They both undergo 222F2-type paraelectric-ferroelectric behavior at around 378 K coupled with clear ferroelastic domain "ON/OFF" switching. Besides, they exhibit an evident thermochromism with color change from orange-yellow to orange-red. To our knowledge, the discovery of integrated ferroelectricity, ferroelasticity, and reversible thermochromism in chiral perovskites is unprecedented.
手性钙钛矿已成为一类重要的材料，在光电子和自旋电子应用方面展现出广阔前景。然而，关于手性钙钛矿铁电体的报道却很少。在这项工作中，我们通过在母体（N-苄基乙烷-1,2-二铵）PbI 的有机阳离子中引入甲基，成功合成了纯手性碘化铅钙钛矿铁电体[(R)-N-(1-苯乙基)乙烷-1,2-二铵]PbI 和[(S)-N-(1-苯乙基)乙烷-1,2-二铵]PbI 。振动圆二色光谱确定了手性镜像关系。它们在约378 K时均呈现222F2型顺电-铁电行为，并伴有明显的铁弹畴“开/关”切换。此外，它们还表现出明显的热致变色现象，颜色从橙黄色变为橙红色。据我们所知，在手性钙钛矿中发现集成铁电性（铁弹性）和可逆热致变色是前所未有的。
