马来酰亚胺修饰的新型三维受体材料的设计、合成及其光伏性能研究

In recent years, organic photovoltaics based on non-fullerene materials have received increasing attention. Perylene diimide (PDI) and its derivatives are the well-known non-fullerene acceptors. However, due to the challenge of functionalization onto PDI, the LUMO energy levels and absorption of such materials cannot be further decreased and broaden, respectively. This project intends to introduce electron-withdrawing maleic acid monoamide unit into PDI, then construct novel three-dimensional acceptors with low LUMO energy levels and broaden absorption via Diels-Alder reaction. By choosing different molecular cores and alkyl chains, we will investigate properties of these materials like photophysics, electrochemistry as well as their self-assembling behavior. Finally, this project aims to use such novel acceptor and low-bandgap donor as active layer to fabricate organic photovoltatic devices, which are expected to show efficient exciton dissociation and high short circuit current. This will also reveal the relationship between molecular structure and device performance, and give new thoughts for developing well-performed three-dimensional acceptors.

非富勒烯受体材料构建的有机太阳能电池近年来得到了广泛的关注。苝二酰亚胺（PDI）是非富勒烯受体材料中的明星分子，然而因对其官能化困难，限制了材料LUMO能级的进一步调控和对太阳光吸收光谱的进一步拓宽。本项目拟在PDI分子上引入吸电子基团的马来酰亚胺，通过Diels–Alder反应高效的合成出新型低LUMO能级、宽吸收的三维受体材料。选择不同的分子核和烷基链，研究对比材料的光物理、电化学以及薄膜态的自组装行为等性质。最终应用到有机太阳能电池器件，实现可以与更多窄带隙给体材料共混作为活化层，达到有效的激子分离和高短路电流的目的，揭示分子结构与器件效率的关系，为进一步设计性能优异的三维受体材料提供新的思路。

本课题实施过程中构建了多种新型有机共轭芳香化合物并对其结构、光物理、电化学及热力学性能进行了系统研究。部分材料应用到钙钛矿太阳能电池和有机场效应晶体管。具体表现在首次发现将金属铟的配合物引入到钙钛矿太阳能电池的空穴传输材料当中，电池的短路电流，开启电压和填充因子均得到了显著的提高，分别是从 19.53 mA/cm2 到 21.03 mA/cm2, 0.98 V 到1.01 V,和 0.67 到0.74。最终，电池的能量转换效率从 12.8% 提高到了 15.8%。同时，铟配合物的引入使得电池的稳定性得到了明显的提高。另一部分重要的工作在于开创了不同稠合单元的非线型氮杂并苯分子，即利用并苯分子的稠合长度搭配茚酮/噻吩/亚砜/砜不同电性类型的稠合单元对并苯分子进行能级的精准调控，进而改变并苯分子的光电性能，同时可以实现电荷的双极传输。