Ordered Matter Science Research Center, Nanchang University, Nanchang, 330031, P. R. China.
Adv Sci (Weinh). 2021 Dec;8(24):e2102614. doi: 10.1002/advs.202102614. Epub 2021 Oct 29.
Ferroelectrics usually exhibit temperature-triggered structural changes, which play crucial roles in controlling their physical properties. However, although light is very striking as a non-contact, non-destructive, and remotely controlled external stimuli, ferroelectric crystals with light-triggered structural changes are very rare, which holds promise for optical control of ferroelectric properties. Here, an organic molecular ferroelectric, N-salicylidene-2,3,4,5,6-pentafluoroaniline (SA-PFA), which shows light-triggered structural change of reversible photoisomerization between cis-enol and trans-keto configuration is reported. SA-PFA presents clear ferroelectricity with the saturate polarization of 0.84 μC cm , larger than those of some typical organic ferroelectrics with thermodynamically structural changes. Benefit from the reversible photoisomerization, the dielectric real part of SA-PFA can be reversibly switched by light. More strikingly, the photoisomerization enables SA-PFA to show reversible optically induced ferroelectric polarization switching. Such intriguing behaviors make SPFA a potential candidate for application in next-generation photo-controlled ferroelectric devices. This work sheds light on further exploration of more excellent molecular ferroelectrics with light-triggered structural changes for optical control of ferroelectric properties.
铁电体通常表现出温度触发的结构变化，这些变化在控制其物理性质方面起着至关重要的作用。然而，尽管光作为一种非接触、非破坏性和远程控制的外部刺激非常引人注目，但具有光触发结构变化的铁电晶体非常罕见，这为铁电性能的光学控制提供了希望。在这里，报告了一种有机分子铁电体 N-水杨醛-2,3,4,5,6-五氟苯胺（SA-PFA），它表现出顺式-烯醇和反式-酮构象之间可逆光致异构化的光触发结构变化。SA-PFA 呈现出明显的铁电性，饱和极化强度为 0.84 μC cm ，大于一些具有热力学结构变化的典型有机铁电体。得益于可逆光致异构化，SA-PFA 的介电实部可以通过光可逆切换。更引人注目的是，光致异构化使 SA-PFA 能够表现出可逆的光诱导铁电极化开关。这种有趣的行为使 SPFA 成为下一代光控铁电器件应用的潜在候选者。这项工作为进一步探索具有光触发结构变化的更优秀的分子铁电体以实现铁电性能的光学控制提供了思路。
