含醌式结构共轭聚合物的研究进展

Recent Progress of Conjugated Polymers Containing Quinoidal Structure

共轭聚合物由于其优异的溶液加工特性和良好的机械性能,近些年来受到了学术界和工业界的广泛关注.将π电子离域性好、刚性强以及LUMO能级低的醌式单元引入共轭主链是构建高性能聚合物半导体材料的潜在方法.然而,如何将醌式结构引入聚合物体系具有一定的挑战.本专论总结了近年来含醌式结构共轭聚合物的研究进展,按照醌式单体的结构分类,介绍了醌式单体的设计与合成,以及含醌式结构共轭聚合物在不同光电器件中的应用,并论述了该领域研究过程中存在的问题和未来发展方向,以期为高性能聚合物半导体材料的开发提供借鉴和指导.

In recent years,conjugated polymers have attracted extensive attention from both industry and academia due to their excellent solution processability and good mechanical properties.The incorporation of quinoidal unit,featured with good π-electron delocalization,rigidity structure and low-lying LUMO energy level,into conjugated backbone is a promising approach to developing high-performance conjugated polymers.However,how to introduce such structure into polymer backbone remains a challenge.In this feature article,we summarized the recent progress of conjugated polymers containing quinoidal structure.According to the structures of quinoidal units,we discussed the design and synthesis of quinoidal monomers.Particularly,we synthesized a series of oxindole-and indandione-terminated quinoidal compounds.The terminal aromatic rings in these quinoidal compounds provide an opportunity to feasibly adjust the properties of conjugated polymers.Furthermore,compared with the reported quinoids,oxindole-and indandione-terminated quinoidal compounds tend to exhibit lower LUMO energy levels,making them promising for the construction of n-type semiconductors.The applications of conjugated polymers containing quinoidal structure in different optoelectronic devices also have been discussed.Such polymers have been widely used in organic thin-film transistors(OTFTs),organic solar cells(OSCs),and organic thermoelectric(OTE)devices.For example,electron mobility of above 1 cm^(2)·V^(-1)·s^(-1) in OTFTs has been obtained for the polymers;air stable n-type OTE devices with power factor above 4.24μW·m^(-1)·K^(-2) can be fabricated based on these polymers.Finally,the current problems and future development directions in the research process of quinoid based polymers are also discussed,hoping to provide useful information for the development of high-performance polymer semiconductor materials.The major issues for this field include:(1)development of new configuration-locking methods for the synthesis of isomer-free quinoid monomers;(2)development of new quinoidal monomers for the synthesis of conjugated polymers with LUMO energy levels below -4.4 eV;(3)synthesis of conjugated polymers using quinoid units for NIR-Ⅱ photothermal therapy.