全共轭聚噻吩类和聚硒吩类嵌段共聚物的凝聚态结构调控

Controlling the Condensed Structure of Polythiophene and Polyselenophene-based All-conjugated Block Copolymers

嵌段共聚物可发生微相分离形成丰富的介观尺度上的相结构,而共轭聚合物是一类具有特殊的力学、导电性能或光电功能的半刚性链高分子.全共轭嵌段共聚物因其兼具两者的特性而备受瞩目.本文着重介绍了近年来课题组在基于全共轭聚(3-烷基噻吩)和聚(3-烷基硒吩)嵌段共聚物体系的研究进展,通过改变体系的分子结构包括主侧链结构、侧链的烷基长度及取代基团等以及对体系在溶液状态及薄膜状态进行后处理包括改变溶剂、热处理、溶剂蒸气处理等来调控体系的微相分离行为和结晶行为,实现对材料凝聚态结构的调控.在此基础上,以有机场效应晶体管和聚合物太阳能电池器件作为最终体现聚噻吩或聚硒吩类体系凝聚态结构与性能关系的平台,将获得的调控体系凝聚态结构的有效策略用于实现其半导体材料物理性能的提升.

Block copolymers can microphase separate into a variety of well-defined nanoscale structures.Conjugated polymers are a kind of semi-rigid macromolecules with special mechanical, conducting, and optoelectronic properties. All-conjugated block semiconducting copolymers have gained immense interest because they combine the optoelectronic properties of conjugated polymers with the fascinating self-assembly properties of block copolymers. In this feature article, we introduced some research progresses on poly(3-alkylthiophene) and poly(3-alkylselenophene)-based all-conjugated diblock copolymers, focusing on controlling the condensed structure of these two systems in our group. By tuning their molecular structures(such as main/side chains, the length of alkyl side chains and side substitutions, etc.), and the post-treatment in their solution and film states(such as changing solvents, aging, thermal and solvent annealing, etc.), the synergy and competition between two basic phase transitions, that is, their microphase-separated behavior and crystalline behavior were systematically studied and clarified. As a result, their condensed structures were efficiently tuned. Furthermore, their optoelectronic properties such as charge mobilities based on their different condensed structures were investigated to build up the relationship among their chemical structures, condensed structures, and device performance. As poly(3-alkylthiophene) and poly(3-alkylselenophene) are model systems with simple molecular structures, the rules and knowledge about controlling their condensed structures obtained from these model systems are expected to be applied in other conjugated systems with more complexed molecular structures and better properties.