基于吡咯并[3,2-b]吡咯结构的有机共轭电子给体的合成及其在有机半导体材料中的应用研究

The design of novel donor and acceptor building blocks is vital to the discovery of high-performance organic conjugated polymers and oligomers, and is the focus of organic electronics field. In the 10-pi electron systems, pyrrolo[3,2-b]pyrrole is known to have the strongest electron donating ability, but also suffer from its electron-rich nature(i.e., very sensitive towards oxidation). Indolo[3,2-b]indole, as its pi-extended derivative, gains some notice as the donor block in organic conjugated systems recently, however, its performance is deteriorated due to its high-lying HOMO energy level and the steric hindrance brought by its terminal benzene ring. Based on our previous work, we plan to solve these problems by re-designing the conjugated system based on pyrrolo[3,2-b]pyrrole core, via strategies such as the introduction of electron-withdrawing group to adjusts its HOMO engery level, and fusing the less-hindered heteroaromatics to the core, etc. The systematic study of the polymer/oligomer based on such novel structures will enrich the donor building block pool, and we hope we could discover 2-3 types of novel organic conjugated polymers/oligomers with outstanding performance in OPVs and OFETs.

新型的给体单元(D)和受体单元(A)的设计的合成对于提高此D-A型有机共轭聚合物以及A-D-A型寡聚物的性能起着至关重要的作用，是有机光电材料研究中的热点。在已知的十电子芳杂环体系中，吡咯并[3,2-b]吡咯给电子能力最强，但也最容易被氧化而不稳定。其衍生物，吲哚并[3,2-b]吲哚，最近在有机共轭材料的研究中开始引起关注，但其光电性能受制于其较高的HOMO能级以及其两端苯环在聚合物或齐聚物体系中所带来的位阻。针对这一问题，在我们前期工作的基础上，我们拟对吲哚并[3,2-b]吲哚的结构进行系统化改造，通过引入拉电子基团、并入位阻更小的芳杂环等手段来达到调节HOMO能级和降低位阻的效果，从而提升基于此类给体单元的聚合物和寡聚物的光电性能。对吡咯并[3,2-b]吡咯衍生物的系统研究对于丰富给体体系有着重要的意义，可望筛选出2-3种在OFET和OPV领域具有优异光电性能的有机共轭材料。

在项目执行期间，我们系统地研究了吡咯并[3,2-b]吡咯衍生物的场效应晶体管性能，解析了构效关系，研究了a.杂原子的引入; b. 烷基侧链的引入；c卤素的引入对材料场效应晶体管性能的影响。在吡咯并[3,2-b]吡咯的核心结构中巧妙地插入了拉电子的羰基，合成的新的受体单元，并系统地研究了其在有机太阳能电池和有机场效应晶体管中的应用，得到了性能优异的宽带隙有机共轭材料，可用于构筑性能优异的宽带隙有机太阳能电池， 在带隙超过2.2 eV的情况下，仍然可以获得超过6%的光电转换效率，且受添加剂、膜厚的影响小，适合于大面积构筑有机太阳能电池。在此基础上，合成了新的含氮杂环—噻唑异靛蓝，在有机场效应晶体管方面展现出优异的性能。我们完成了筛选出2-3种在OFET和OPV领域具有优异光电性能的有机共轭材料的目标。在此过程中，我们发表SCI论文10篇，培养博士生3名，硕士生1名。