基于醌式芳香单元的n型共轭聚合物的设计、合成与表征

Considering the lack of high electron mobility and air-stable n-type conjugated polymers, in this project, we will design and synthesize quinoidal aromatics with low LUMO and HOMO energy levels for the construction of n-type conjugated polymers featuring with high planar backbone and strong intermolecular interaction. The protocols for the efficient synthesis of this quinoidal units will be explored, and their LUMO and HOMO energy levels will be lowered by introducing electron-withdrawing groups such as cyano, amide and imide. Steric effect and/or weak intramolecular interactions will be employed to restrict the isomers of quinoidal aromatics. HOMO and LUMO energy levels, backbone conformations and condensed state structures of the resultant conjugated polymers will be tuned by using different co-monomers and optimizing polymerization conditions. Via these studies, we hope to establish the relationship between molecular structures, condensed state structures and device performance, and finally, to develop n-type conjugated polymers with high electron mobility and great ambient device-stability.

鉴于有机薄膜晶体管（OTFT）器件性能稳定的高迁移率n型共轭聚合物匮乏的问题，本项目将设计与合成具有低HOMO和LUMO能级的可聚合醌式芳香单元，并以此构筑平面性好、分子间作用力强的n型共轭聚合物。探索可聚合醌式芳香单元的高效合成路线，引入腈基、酰胺、酰亚胺等强吸电子基团，降低醌式芳香单元的HOMO和LUMO能级，利用取代基的位阻效应以及分子内弱相互作用，抑制异构体的生成。通过与不同芳香单元共聚，优化聚合条件，协同调控聚合物的HOMO和LUMO能级、链构象和聚集态结构，建立分子结构-聚集态结构-器件性能之间的关系，发展电子迁移率高且空气中器件性能稳定的n型共轭聚合物新体系。

低LUMO能级共轭聚合物的缺乏是目前n型半导体材料发展远远落后于p型半导体材料的重要原因。本项目针对这一问题，提出在聚合物链骨架引入醌式单元降低聚合物LUMO能级的分子设计策略，从而实现共轭聚合物的n型传输特性。实现了吲哚酮封端醌式单体的高效合成，结合对聚合物链构象的调节，基于此类醌式单体获得了电子迁移率达到0.49 cm2 V-1 s-1的n型共轭聚合物；基于苯并二吡咯烷酮醌式单体开发了电子迁移率超过1 cm2 V-1 s-1的n型共轭聚合物，为目前含醌式结构共轭聚合物的最高电子迁移率；发展了茚满二酮封端的醌式化合物体系，探究了端基修饰对醌式化合物光电性质的影响。这些研究为n型共轭聚合物的合成提供了新的分子设计新概念，有助于推动n型共轭聚合物的发展。