Liu Hui-Yu, Zhang Han-Yue, Chen Xiao-Gang, Xiong Ren-Gen
Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing 211189, People's Republic of China.
J Am Chem Soc. 2020 Sep 9;142(36):15205-15218. doi: 10.1021/jacs.0c07055. Epub 2020 Aug 30.
Ferroelectric materials have a variety of technological applications, as transducers, capacitors, sensors, etc. Great interest in molecular ferroelectrics has emerged because of their structural flexibility, tunability, and homochirality. However, the discoveries of molecular ferroelectrics are not abundant. The lack of chemical design is the main challenge in realizing new molecular ferroelectrics. Consequently, chemical design approaches, including the ideas of introducing quasi-spherical theory, homochirality, and H/F substitution, have been developed recently. Through these advanced methodologies, a wide range of ferroelectrics were successfully synthesized, changing the blind search into a targeted chemical design. In this Perspective, we aim to provide insight into the fundamental chemistry and physics of molecular ferroelectrics and propose the concept of "ferroelectrochemistry", concerned with the targeted design and performance optimization of molecular ferroelectrics from the chemical point of view. We start with the basic theories used in the modification of chemical structures for new molecular ferroelectrics, such as the quasi-spherical theory. After that, we focus on the fundamentals of homochirality from the perspective of chemistry and advantages of introducing a homochiral molecule within the scope of ferroelectrics. Further, we explore another design strategy, H/F substitution, as an analogue of the H/D isotope effect. The introduction of a F atom usually does not change the polar point group but may induce a minor structural disruption that enhances physical properties such as Curie temperature and spontaneous polarization. We hope our comprehensive studies on the targeted design and performance optimization strategies for molecular ferroelectrics may build up and enrich the content of ferroelectrochemistry.
铁电材料有多种技术应用，如作为换能器、电容器、传感器等。由于其结构的灵活性、可调性和同手性，人们对分子铁电体产生了浓厚兴趣。然而，分子铁电体的发现并不丰富。缺乏化学设计是实现新型分子铁电体的主要挑战。因此，最近已经开发了化学设计方法，包括引入准球形理论、同手性和H/F取代等概念。通过这些先进方法，成功合成了多种铁电体，将盲目搜索转变为有针对性的化学设计。在这篇展望文章中，我们旨在深入了解分子铁电体的基础化学和物理，并提出“铁电化学”的概念，即从化学角度关注分子铁电体的靶向设计和性能优化。我们从用于新型分子铁电体化学结构修饰的基本理论开始，如准球形理论。之后，我们从化学角度关注同手性的基本原理以及在铁电体范围内引入同手性分子的优势。此外，我们探索另一种设计策略，即H/F取代，作为H/D同位素效应的类似物。引入F原子通常不会改变极性点群，但可能会引起轻微的结构破坏，从而增强诸如居里温度和自发极化等物理性质。我们希望我们对分子铁电体靶向设计和性能优化策略的全面研究能够建立并丰富铁电化学的内容。
