Optically Controlled Polarization Switching in an Organic Ferroelectric with Light- and Temperature-Triggered Phase Transitions

Abstract

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.

Molecular Cage with Dual Outputs of Photochromism and Luminescence Both in Solution and the Solid State

“…Many conventional photochromic luminophores, e.g., azobenzenes, diarylethenes, , spiropyrans, , and so on, , suffer from the aggregation-caused quenching (ACQ) effect at high concentrations . One potential solution to this ACQ problem is covalently coupling the photochromic unit with AIEgens, i.e., materials exhibiting aggregation-induced emission (AIE) properties.…”

“…Compared to other stimuli-responsive materials, 1−7 this class of photoactive compounds have unique advantages, such as contactless control and quick responsiveness, which have enabled their wide applications such as in photoresponsive materials, 8−11 biomedical materials, 12−14 and supramolecular materials. 15−17 Many conventional photochromic luminophores, e.g., azobenzenes, 18 diarylethenes, 19,20 spiropyrans, 21,22 and so on, 23,24 suffer from the aggregation-caused quenching (ACQ) effect at high concentrations. 25 One potential solution to this ACQ problem is covalently coupling the photochromic unit with AIEgens, i.e., materials exhibiting aggregation-induced emission (AIE) 26 properties.…”

Light-Driven Domain Switching on a Photochromic Ferroelectric

“…Under the ambient condition, t Bu-2-FSA possessed the enol form in the solid state, as depicted in Figure b. The plausible mechanism for photochromism is the proton transfer-induced structural transition, where proton transfer from the hydroxyl group (enol form) to the nitrogen and lead to the formation of ketone (trans–keto form). − We also checked the thermal transformation of t Bu-2-FSA from the trans–keto form to enol form by the color change (Figure S3). As shown in Figure c, in order to investigate the photochromic properties, UV–vis absorption measurements were conducted by various light irradiation treatments.…”

“…The structural phase transition caused by photoisomerization was found to be associated with ferroelectricity. − Those conformation-adjustable SA and its derivatives with polar structures are highly expected as photochromic ferroelectrics, where ferroelectric domains can also be switched by non-destructive light irradiation. Although the photochromic characteristics, thermochromic characteristics, crystal, dielectrics, and phase transitions of typical SA derivatives have been extensively studied, − the ferroelectric domain switching in a photochromic SA without thermodynamic structural phase transition has rarely been discussed. ,, …”

Tin-based organic–inorganic metal halides with a reversible phase transition and thermochromic response

“…[1][2][3][4][5][6][7][8][9][10] The perfect combination of organic and inorganic components provides feasibility for the occurrence of phase transition behavior. [11][12][13] At the same time, dielectric phase transition (thermally stimulated response) materials often bring about interesting physical properties such as fluorescence, [14][15][16] thermochromism, [17][18][19][20] ferroelectricity [21][22][23] and so on. [24][25][26][27][28][29][30] Compared with high-dimensional hybrid phase transition materials with limited organic ammonium species, the structures of low-dimensional compounds are more flexible and diverse.…”