有机太阳电池（OSCs）具有质轻、可弯曲、低成本的等特点而受到了人们的广泛关注。设计和开发新型活性层给受、体材料是进一步提高体异质结有机太阳电池器件性能的关键。特别是在过去的几年中，基于非富勒烯电子受体的有机太阳电池效率已经实现了超过18%。苝二酰亚胺（PDI）衍生物由于其具有高电子迁移率、在可见光谱区强吸收、能级易调节和高热稳定性而成为一类代表性的电子受体材料。然而，PDI单元的大平面π共轭骨架易于形成大的聚集体，导致未修饰的PDI光伏性能较差。为了抑制PDI受体的过度聚集，研究者致力于发展非平面结构的PDI受体材料。本文围绕构建非平面型PDI分子开展工作，设计合成了两个系列的新型PDI衍生物，并将这些电子受体材料应用于有机太阳电池，研究了其光电转换性能。

       首先，以二元稠合PDI单元（FPDI-T）为基础设计并合成了两种四元PDI分子S-TFPDI-MFT和S-TFPDI-FT，分别是呈T型结构的S-TFPDI-FT和H型结构的S-TFPDI-MFT。相比FPDI-T，S-TFPDI-FT加大了分子的扭曲程度，减弱了分子的聚集程度，活性层的形貌得到了优化，提高了载流子迁移率，获得了7.78%的PCE。而S-TFPDI-MFT虽然具有一定程度扭曲结构，但其p-p堆积距离较小，共混膜形貌较差，载流子迁移率不高，获得了4.46%的PCE。

       其次，用单键将两个PDI单元连接到咔唑中心核，并尝试在PDI单元的bay位插入环化硫原子和硒原子，合成了C-diPDI、C-diPDI-S和C-diPDI-Se。三者的PDI单元与中心核呈现不同的夹角，C-diPDI、C-diPDI-S和C-diPDI-Se二面角分别是55°，65°和62°。其中C-diPDI-S的分子构型扭曲程度最大，有效抑制了PDI基团的大尺度聚集，得到较为合适的相分离尺寸。基于PBDB-T:C-diPDI-S的器件获得了5.41%的PCE；基于PBDB-T:C-diPDI/C-diPDI-Se的器件获得了4.95%和5.04%的PCE。

Given the attractive features of light weight, mechanical flexibility and low cost, organic solar cells (OSCs) have attracted extensive attention. Designing and exploiting novel donor/acceptor materials for the active layer is the key to further enhance the performance of BHJ OSCs. Particularly in the last few years, the non-fullerene OSCs have achieved an outstanding power conversion efficiency (PCE) of over 18%. Perylene diimide (PDI) derivatives are potential acceptors in non-fullerene organic solar cells due to their high electron mobility, strong absorption in the visible region, tunable energy level and excellent thermal stability. However, the large planar π-conjugated system of the PDI unit is prone to form excessive self-aggregation, which may lead to poor photovoltaic performance. In order to overcome these above shortcomings of PDI, many researchers are devoted to develop non-planar PDI acceptors. Focused on constructing non-planar PDI acceptors, two series of new PDI derivatives were designed and synthesized in this artical. Using these new acceptor materials, we construct a series of OSCs to study their photoelectric properties.

Firstly, a series of quaternary PDI acceptors S-TFPDI-FT and S-TFPDI-MFT which have a T-shaped/H-shaped molecular structure were designed and synthesized on the basis of binary fused PDI unit (FPDI-T). Due to the increase of twist in S-TFPDI-FT compared to FPDI-T, the molecular aggregation is greatly eased. As expected, S-TFPDI-FT showed a better morphology as well as balanced and better charge carrier mobility. Devices based on PBDB-T:S-TFPDI-FT achieved a PCE of 7.78%. Though S-TFPDI-MFT showed a excessively twisted molecular comformation, its p-p stacking distance is smaller than that of S-TFPDI-FT. The blend film of PBDB-T:S-TFPDI-MFT showed a poor morphology as well as charge carrier mobilities. As a result, devices based on PBDB-T:S-TFPDI-MFT obtained a worse PCE of 4.46%.

Secondly, three binary PDI acceptors C-diPDI, C-diPDI-S and C-diPDI-Se based on a carbazole core connected with two PDI were designed and synthesized. C-diPDI-S and C-DIPDI-Se were annulated at the bay positions of the PDI units by sulfur (S), and selenium (Se) respectively. The average dihedral angles between the carbazole core and the PDI units were 55° for C-diPDI, 65° for C-diPDI-S, and 62° for C-diPDI-Se. So C-diPDI-S had a most severe twisted molecular skeleton which strongly suppressed the aggregation. Finally, organic solar cells based on PBDB-T:C-diPDI-S exhibited a higher PCE of 5.41%. However, the PBDB-T:C-diPDI and PBDB-T:C-diPDI-Se based devices only showed a PCE of 4.95% and 5.04% respectively.