有机-无机杂化反钙钛矿铁电体定向设计与合成

Antiperovskites are a class of important functional materials developed in recent decades due to their excellent physical properties such as negative thermal expansion and superconductivity etc. However, ferroelectricity has always been unachieved in the inorganic counterpart, like fishing in the air. The main reason is that inorganic oxide structures with highly central symmetry do not match the ferroelectric nature of polar space groups. Organic-inorganic hybrid systems with structural flexibility, tunability, and structural diversity, overcoming the limitation of antiperovskite ferroelectricity in inorganic ceramics, are an important platform for the discovery of new types of very promising functional materials. However, it is not that easy to find new organic-inorganic hybrid antiperovskite ferroelectrics. This project intends to adopt the strategy of molecular design in the organic-inorganic hybrid system, the corresponding chemical modification is carried out to synthesize new and optimized antiperovskite molecular ferroelectrics with large spontaneous polarization, small coercivity field and easy domain switching, etc. The molecular design approach is introduced into the design of organic-inorganic hybrid antiperovskite molecular ferroelectric, which provides a new idea for the development of antiperovskite ferroelectric and plays a positive role in promoting the development of molecular ferroelectric materials.

反钙钛矿化合物因具有良好的负热膨胀、超导等物理性能，成为近几十年来发展起来的一类重要功能材料。然而铁电性一直是无机反钙钛矿材料无法实现的，犹如水中捞月。其主要原因在于具有高度中心对称性的无机氧化物结构与极性空间群的铁电本质不匹配。有机-无机杂化体系具备结构灵活性和可调谐性，并且结构多样化，而且突破了反钙钛矿铁电性在无机陶瓷中的限制，是一个发掘新型多功能材料非常重要的平台。然而寻找新的有机-无机杂化反钙钛矿铁电体的难度依然巨大。本项目拟在有机-无机杂化体系中采用定向分子设计的策略，基于已存在的反钙钛矿结构，对其进行相应的化学修饰，合成得到新的以及性能优化的反钙钛矿分子铁电体，其具备自发极化较大、矫顽场较小、畴易翻转等性质。将分子设计思想引入有机-无机杂化反钙钛矿分子铁电设计中，为反钙钛矿铁电的开发提供了新思路，也为分子铁电材料的发展起到积极的推动作用。

铁电体是能源、传感、信息等领域的重要功能材料，分子铁电材料具有柔韧性、生物兼容性、轻质等优势，符合国家在科技创新领域的重大需求。本项目拟在有机-无机杂化体系中采用定向分子设计的策略，基于我们前期已报道的反钙钛矿结构，对其进行化学修饰，合成得到性能优异的新型反钙钛矿分子铁电体。在按照项目既定的研究内容执行过程中，我们意外地发现了几例具有显著优异性能的新型分子铁电材料，例如具有优越横向压电性能的钙钛矿分子铁电体和具有显著热致变色铁弹分子铁电体。该项目利用分子设计手段不仅为新型分子铁电体的开发提供了新思路，而且也为分子铁电材料的发展起到积极的推动作用。在该项目的资助下，项目负责人以一作或通讯作者身份发表SCI论文13篇，其中影响因子大于3.0的文章13篇，包括J.Am.Chem.Soc.1篇、Angew.Chem.Int.Ed.1篇、Chem.Sci.1篇、Adv.Sci.1篇、Chem.Mater.1篇、Chem.Commun.1篇等。项目负责人获批2022年度国家自然科学基金委优秀青年科学基金项目。