基于骨架调控和侧链修饰的新型非富勒烯受体材料研究

Polymer solar cells (PSCs) based on the bulk heterojunction structure have achieved tremendous progress, in which the highly efficient A-D-A type non-fullerene acceptors with finely modulated energy levels have played an important role. Using skeleton regulation and side chain engineering, a series of excellent conjugated small molecules with tunable energy levels and improved photovoltaic properties have been achieved. Recently, the studies have been mainly focused on transforming the donor, acceptor and bridge units and their side chains based on indacenodithiophene (IDT) or indacenodithieno[3,2-b]thiophene (IDTT) fused rings. However, the effections of the ring size of donor unit, electron density and side chains of the initial core on the energy levels and performances have been seldom investigated.. In this proposal, we will focus on investigating the influences of the electron density and side chains of the initial nucleus of dibenzo[b,d]-pentahedral-fused ring (fluorene, carbazole, dibenzo[b,d]silole, dibenzo[b,d]furan, dibenzo[b,d]thiophene and dibenzo[b,d]thiophene-5,5’-dioxide) on the energy levels and the power conversion efficiency (PCE). Furthermore, the ring size of donor unit between fused thiophenes and dibenzo[b,d]-pentahedral-fused ring, and the position and type of side chains based on fused thiophenes will be examined. Based on the preliminary work, highly efficient non-fullerene acceptors will be synthesized and characterized. And then, photovoltaic performance of PSCs based on the acceptors blending with suitable polymer donors will be formed and optimized to obtain enhanced PCE. Through systematic study of the acceptors, we want to clarify the rules of the skeleton regulation and side chain engineering on the performance of PSCs to in-depth understand the relationship between molecular structure and performance, which is of great importance in the design and synthesis of novel A-D-A type acceptor materials and the performance enhancement of PSCs.

基于高效A-D-A型非富勒烯受体材料聚合物光伏电池已取得了巨大进展，通过骨架调控和侧链修饰，实现了分子能级的调节和光伏性能的提升。目前集中于变换引达省类（IDT或IDTT）D、A单元、桥连单元及其侧链调节材料性能，而针对D单元环大小及起始母核电子云密度、侧链的微调控对光伏性能的影响尚未引起重视。.本项目在前期基础上设计和制备小分子受体材料，系统研究芴、咔唑等二苯并五元芳杂环、多并噻吩与噻吩构建多并稠环A-D-A型共轭分子，考察环大小对能级的影响，并研究二苯并五元芳杂环原子种类、侧链及多并噻吩类D单元侧链种类、位置对光伏性能的影响。选择合适的给体聚合物制备光伏器件，系统研究光伏电池性能，提升聚合物光伏电池光电转换效率。本项目的实施，对于深入理解材料结构和性能之间的关系，阐明骨架调控、侧链调节对性能影响的规律，为高效非富勒烯受体材料的设计与合成及实现聚合物光伏电池性能的继续提升具有重要意义。

近年来，基于A-D-A型非富勒烯受体材料的聚合物太阳能电池取得了快速发展，单层电池效率已经达到18%。本项目针对目前D单元环大小及起始母核电子云密度、侧链的微调对受体材料光伏性能影响等关键科学问题，以茚并芴、二苯并五元芳杂等给电子单元，设计合成了一系列A-D-A型宽光谱响应的非富勒烯受体材料，研究了材料的光物理性能、热稳定性、电化学性能及光伏性能等。通过器件优化，获得了高效稳定的聚合物太阳能电池器件。其中，基于茚并芴稠环给体材料的本体异质结有机太阳能电池效率达到7.84%，揭示了中心母核电子云及原子种类对材料性能的影响规律，为新型非富勒烯受体材料设计提供理论指导。在项目支持下，开展了侧链工程在基于硫脲染料分子中的应用研究。通过器件优化，基于烷基苯基取代的染料分子在染料敏化太阳能电池效率达到7.88%。同时考查了供体单元结构对染料分子在共敏体系中器件性能的影响规律，将N719共敏体系效率由7.29%提升至8.02%。此外，开展了D-A型窄带隙聚合物给体材料的设计与合成，阐明了双氟原子在异靛蓝不同取代位置对光伏性能影响机制，为高效D-A型聚合物给体材料设计提供新方法。.本项目的实施对于解决A-D-A型非富勒烯受体材料的关键问题，获得高性能的给受体材料及其稳定器件，促进非富勒烯受体材料和给体材料在聚合物太阳能电池的应用具有重要的理论和现实意义。依托本项目，项目负责人在国内外期刊上发表论文8篇，授权专利3件，本项目的研究成果或许为非富勒烯受体材料、染料分子及聚合物给体材料的设计提供了一条新思路。