基于大分子芳酰亚胺类高效有机光伏器件的激子解离驱动力研究

As a new type of photoelectric conversion device, organic solar cells (OSCs) have become a focused area in the field of photovoltaic in recent years. Fused-ring perylene diimides (PDIs), as a classical type of electron acceptor material have been the most potential one with a wide band-gap, due to the excellent extinction coefficient, good carrier mobility and outstanding chemical and thermal stability. At present, the high-performance PDIs acceptors are composed of multiple PDI units, making it more difficult to construct the relationship between molecular structure and photo-to-current conversion process. At the same time, the OSCs can still achieve good exciton dissociation even with a small energy level offset between donor and acceptor. Thus, more comprehensive and in-depth exploration should be taken on to determine the source and the optimal value of exciton dissociation driving force. This project is intended to be established in the fused-ring PDIs derivatives. We will reveal the influence of fused-ring degree on the dielectric constant, reorganization energy and molecular dipole. Following, an internal connection between the molecular structure, aggregation morphology and device performance will be established. At last, we will reveal the origin of exciton dissociation driving force and charge recombination mechanism for the OSCs with low energy loss, and therefore provide scientific guide for further improvement of molecular structure and device performance.

有机光伏器件作为一类新型的光电转换器件，近年来成为光伏领域的研究热点。作为电子受体材料的稠环苝酰亚胺（PDIs）类衍生物因具有优异的消光系数、良好的载流子迁移率和突出的化学、热稳定性，成为当前最具发展潜力的一类宽带隙受体材料。目前高性能的稠环PDIs类受体材料均是由多个PDI单元稠合而成，分子的高度稠合化加大了分子结构-光电转换过程之间关系的构筑难度；同时，该类电池在低给、受体能级差下仍能实现良好的激子解离，因此对于激子解离驱动力的来源及电荷的复合机制需要更加全面深入的探索。本项目立足于特色鲜明的稠环PDIs类衍生物，通过揭示分子的稠合度大小对介电常数、重组能、分子偶极等物化性质的影响规律，建立大分子PDIs类受体材料的分子结构与聚集态形貌、器件性能之间的内在联系，从而揭示该类光伏器件在低能级差条件下所需的激子解离驱动力来源和电荷复合机制，拟为有机光伏材料的分子结构和性能改进提供科学指导。

有机光伏器件作为一类新型的光电转换器件，近年来成为光伏领域的研究热点。其中，构筑光活性层的一类重要的电子受体材料---稠环苝酰亚胺（PDIs）类衍生物，因具有优异的消光系数、良好的载流子迁移率和突出的化学/热稳定性等，成为当前最具发展潜力的宽带隙受体材料。目前高性能的稠环PDIs类受体材料均是由多个PDI单元稠合而成，分子的高度稠合化加大了分子结构-光电转换过程之间关系的构筑难度；同时，该类电池在低给、受体能级差下仍能实现良好的激子解离，因此对于激子解离驱动力的来源及电荷的复合机制需要更加全面深入的探索。本项目针对特色鲜明的稠环芳酰亚胺类衍生物体系开展了系统性研究工作，包括基于稠环芳酰亚胺类材料的设计与合成，以及聚合物太阳能电池的制备与研究两部分内容，主要内容如下：通过揭示分子结构与物化性质之间的影响规律，建立了大分子芳酰亚胺类受体材料的分子结构与聚集态形貌、器件性能之间的内在联系，并尝试揭示该类光伏器件在低能级差条件下所需的激子解离驱动力来源和电荷复合机制，为有机光伏材料的分子结构和性能改进提供了科学指导。