基于有机膦酸的分子基铁电体的合成与性质研究

Ferroelectrics are recognized as an important class of advanced material with a wide range of applications in data storage, infrared detection, energy harvesting, optoelectronic device, and many other high-tech fields. The exploring of ferroelectric materials is a hot topic in physics, chemistry and materials science. In recent years, the molecule-based ferroelectrics have attracted much attention because they can not only provide new ideas but also act as potential candidates for the application and development of ferroelectric material. In this research project, we have noted that phosphonate group features some potential advantages on the syntheses of molecule-based ferroelectrics, and we will design appropriate phosphonic acids as the primary building blocks to assemble new molecule-based ferroelectrics. The "composition-structure-properties" of such ferroelectrics will be thoroughly investigated via the X-ray crystal structure analysis, conventional physical and chemical characterizations, and modern spectroscopic techniques, especially the dielectric and ferroelectric experiments. Finally, the mechanisms of the polarization and ferroelectric phase transition in such ferroelectrics are expected to be clarified, and the functions of the phosphonate group on the assembly of molecule-based ferroelectrics will be summarized. Through this project, we also seek to obtain ferroelectric crystals with good properties for practical application.

铁电材料是铁电存储、红外探测、机电转换、光电器件等众多高新技术领域中一类非常重要的先进功能材料。探寻、制备具有优良性能的铁电材料是物理学、化学、材料学等学科共同关注的一个热点。近年来，在各类铁电材料的研究中，新兴的分子基铁电体由于能够为铁电材料的应用与开发提供新的思路和素材而受到重视。在本研究项目中，我们注意到有机膦酸基在构筑合成分子基铁电体中的一些潜在优势，因此拟设计合成特定的有机膦酸分子，或者将膦酸基嫁接到某些功能基团上，通过控制适当的条件来组装、制备新型分子基铁电体。应用X射线单晶结构分析、常规理化表征、现代谱学技术，尤其是介电、铁电性能测试等手段来分析研究这类分子基铁电体的组成、结构、性能及它们之间的关系。通过对这类铁电体电极化的产生与调控的研究，阐明其极化和铁电相变机制，总结膦酸基在构筑合成分子基铁电体中的特点和功能；同时也力图筛选获得实用性能优良的铁电晶体。

电极化材料（如介电、压电、热释电、铁电材料）是现代电工电子装置的重要组件。探寻、制备具有优良性能的电极化材料是物理学、化学、材料学等学科共同关注的一个热点。近年来，新兴的分子基电极化材料由于能够为介电、铁电材料的应用与开发提供新的思路和素材而受到重视。在本研究项目中，我们主要设计合成了一系列基于膦酸及其四面体构型类似物（如次膦酸、卤代铬酸根、一水合三卤化锌离子团等）的共晶化合物和配位聚合物，以及一系列基于叠氮的类钙钛矿配位聚合物。应用X射线单晶结构分析、常规理化表征、现代谱学技术，尤其是介电、铁电性能测试及分子动力学模拟等手段来分析研究这类分子基电极化材料的组成、结构、固态相变、性能及它们之间的关系。通过对这些固态分子基化合物的系统研究，总结了这些化合物电极化效应的调控规律，阐明了微观结构与宏观极化性质的内在联系，以及外界温度变化对其极化性质的影响等。