Hybrid Molecular Ferroelectrics, a Promising System with Unique and Outstanding Electromechanical Properties

Organic-inorganic hybrid ferroelectrics (OIHFs) is a novel member of ferroelectrics family comprised of both organic and inorganic parts as its building block. Since the year of 2014, tens of OIHF structures have been explored with striking progress made in electromechanical properties such as high ferroelastic strain output and piezoelectricity. Recently, giant d33 (1540 pC/N) and strain output (21.5%) were reported in this ferroelectric system, which are much higher (by around three times and two orders of magnitude, respectively) than those of lead zirconate titanate (PZT). These enmerging outstanding properties indicates their bright future as lightweight and high-performance electromechanical materials. Different with the widely used piezoelectric enhancement methods such as morphotropic phase boundary (MPB) effect in oxide perovskite, the strain/piezoelectricity enhancement strategies for OIHF are involved with special molecular engineering. In addition, the bond engineering in OIHF show bright future for high-performance soft piezoelectrics. With our works, I will report: 1. The space-confinement structure enables giant strain output of 21.5% and d35 of 4800 pm/V in an OIHF. 2. The bond weakening strategy renders high-performance soft piezoelectrics, in which the materials show orders of magnitudes higher power output (11W/m2) than general piezoelectric ceramics and simultaneously, excellent mechanical softness (0.8 GPa) better than PVDF (2 GPa). These results promise OIHF unique positions in ferroelectrics family, especially in actuator and in soft electronics applications.<br/><br/>Authors: Yuzhong Hu, Marin Alexe, Hong Jin Fan, Junling Wang, Pooi See Lee.<br/><br/>Some of the related works:<br/>Yuzhong Hu et al., Nature Materials, 20.5 (2021): 612-617<br/>Yuzhong Hu et al., Nature Communications, 13 (2022): 5607