[R-3-hydroxylpiperidinium]2SbCl5 is a photoluminescent chiral lead-free organic–inorganic ferroelastic semiconductor showing switchable second-harmonic generation response and clear ferroelastic domains.

Organic single-component ferroelectrics, as an important kind of metal-free ferroelectrics, are highly desirable for their easy processing, mechanical flexibility, and biocompatibility. However, although nearly 50 years have passed since the...

Polarization in ferroelectrics is generally switched by an applied external electric field. Light is highly attractive as a noncontact and noninvasive means, but optically controlled ferroelectric polarization has been mainly realized in some inorganic ferroelectrics, and rarely found in molecular ferroelectrics, which have superiorities of easy processing, light weight, mechanical flexibility, and good biocompatibility. In this work, we reported an organic ferroelectric salicylideneaniline derivative N-3,5-di-tert-butylsalicylidene-2-aminoaniline (1), which shows optically controlled polarization switching. 1 not only exhibits a light-induced phase transition of photoisomerization between enol and trans-keto molecular configurations but also presents a temperature-triggered phase transition at around 364 K related to the order–disorder transition of a tert-butyl group in the structure. P–E (polarization–electric field) hysteresis loops and box-in-box ferroelectric domain reversal confirm its ferroelectricity. Upon photoirradiation, the ferroelectric domains show obvious variations and demonstrate reversible polarization switching under UV and visible light, originating from the photoinduced structural isomerization. This finding sheds light on the development of molecular ferroelectrics with noncontact and remote control of polarization switching by light for potential application in next-generation optically controlled ferroelectric devices.

[(S)-3-Aminopyrrolidinium I]2Bi2/3I4 is a novel chiral two-dimensional perovskite-like lead-free bismuth(iii) iodide hybrid showing a high phase transition temperature and a narrow bandgap.