多极轴分子铁电薄膜

Recent development of molecular ferroelectrics (MFE) has made tremendous progress on the saturate polarization and transition temperature, which are comparable/exceeding to those of conventional inorganic ferroelectric ceramics. Such progress established the role of MFE as important supplementary element to conventional inorganic ferroelectrics. While the multiple-ferroelectric-axes feature has been proven to provide irreplaceable contribution to the performance of inorganic ferroelectric ceramics, however, as an important functional element, the ferroelectric axis, especially multiple-ferroelectric-axes, is remains an unexplored problem in the field of MFE. Almost all the newly discovered MFE have only one ferroelectric axis. Such a uniaxial characteristic greatly limits the development of MFE as polycrystalline materials, especially in the application of ferroelectric thin-films. In this proposal, we are planning to study the multiaxial element in MFE system. Based on our experimental experiences and theoretical background in discovery of new MFE, we will study the controllable synthesis of MFE with multiple-ferroelectric-axes and their self-assembly thin-film preparation. Other than fundamental study, we would develop a systematic method of in-situ characterization on the microscopic properties of multiaxial MFE in real-time. Such a method will allow us to probe the effect of multiaxial feature on the local domain-dynamics, as well as the polarization reversal mechanisms. By study those microscopic multiaxial properties, we can obtain valuable information which will offer effective guidance to our synthesis and optimization on the multiaxial ferroelectric thin-film.

随着研究的深入与发展，近些年来发现的许多新型分子铁电体无论在饱和极化值或者相变温度等关键性参数上都接近或超过了传统的无机陶瓷铁电材料，确立了分子铁电体作为无机陶瓷的有益补充这一关键地位。然而迄今为止，绝大多数明星分子仅具有一个铁电极轴，在分子铁电体的研究中也极少有针对多重极轴的研究和报道。相比于具有三个甚至六个极轴的无机陶瓷铁电体，单极轴特性严重的制约了分子铁电体在多晶态应用中，尤其是薄膜化应用的发展和潜力。在本项目中，我们从铁电极轴这一重要的功能基元入手，结合在分子铁电研究中获得的宝贵经验，通过分子设计和结构优化实现多极轴分子铁电体的可控合成，并探索其薄膜材料的自组装方法，最终获得具有优异宏观铁电性能的多极轴分子铁电薄膜。同时，建立起一套针对多极轴分子铁电薄膜的微区表征手段，实时、原位的研究多极轴特性对铁电畴反转、畴壁移动等动力学过程的影响机制，为多极轴分子铁电体的研究提供有益的帮助。

本项目以“多极轴分子铁电薄膜”为研究方向，针对分子铁电研究中面向应用产生的多极轴问题，以极轴特性这一功能基元为研究重点，以薄膜形式的分子铁电体为研究体系，针对函待解决的问题和限制，从结构设计出发，可控制备了多种多极轴分子铁电体，并对极轴特性进行优化，最终发展出一套可行性较强的多极轴分子设计方法。并通过制作多种分子薄膜，探索了多极轴分子铁电材料的应用前景。