含方酸共价有机框架材料的理论设计与光电性质研究

Covalent organic frameworks (COFs) are widely studied in field of materials, and behavior well in luminescence, charge transfer and light-harvesting area. Squaraine (SQ) performs excellent nonlinear optical property, so that COFs with SQ might be a promising nonlinear optical material. In this project, the concept of "bottom-up" reticular chemistry is employed, and 1,3-aromatic amine substituted SQ and other 5 types of aromatic units are matchedly chosen to build 2D and 3D COFs. The first principle methods based on HSE methods are used to calculate the electronical structure, dielectric function and 2nd-order nonlinear susceptibility of these novel COFs, furthermore the effects of external fileds on electronical structure and optical properties are also studied. The microscopic mechanism of effect of SQ on optical and electronic properties can be revealed in this project. What’s more, it is promising to find out the strategy for improving nonlinear optical property and thus provide theoretical guide for experimental synthesis.

共价有机框架材料 (Covalent organic frameworks, COFs) 是材料领域的一个研究热点，在荧光、电荷传输与光捕捉方面表现出优良性质。方酸化合物 (Squaraine, SQ) 具有优良的非线性光学特性，含方酸的功能化COF材料则有可能成为一种潜在的非线性光学材料。本项目依据“自下而上”-框架化学 (“Bottom-up” reticular chemistry) 的概念，选用1,3-二芳香胺取代方酸与其他5种芳香性分子以结构匹配的方式构筑出二维、三维新型COFs材料。拟通过基于杂化泛函（HSE）方法的第一性原理计算研究所构筑材料的电子结构、介电函数以及二阶非线性极化率，并研究在外部场源环境下材料电学、光学性质的变化。本项目可以从微观机理上揭示方酸分子对材料光学、电学性质的影响，有望发现改进材料非线性光学特性的途径，从而为实验合成提供理论指导。

多孔材料在化工、环境及能源领域发挥着重要作用。然而，基于实验手段研究影响多孔材料性能的微观机制仍然存在难度。结构决定性质，通过基于密度泛函的第一性原理计算和基于分子力场的分子模拟相结合这一多尺度理论方法来设计材料并预测其宏观性能，将有助于实现应用导向设计。本项目主要完成了以下两方面工作：①依据“自下而上”-框架化学 (“Bottom-up” reticular chemistry) 的概念，利用特定结构单元来构筑二维或三维共价有机框架(COF)材料，从而改进材料的电学、光学以及吸附扩散等性能；②研究典型无机多孔材料分子筛(zeolites)在催化、吸附以及扩散等方面的行为，揭示分子筛限域孔道中的构-效关联。