Rehman Tahir, Liu Zhi-Xi, Lau Tsz-Ki, Yu Zhipeng, Shi Minmin, Lu Xinhui, Li Chang-Zhi, Chen Hongzheng
MOE Key Laboratory of Macromolecular Synthesis and Functionalization, State Key Laboratory of Silicon Materials, Department of Polymer Science and Engineering , Zhejiang University , Hangzhou 310027 , China.
Department of Physics , The Chinese University of Hong Kong , New Territories , Hong Kong , China.
ACS Appl Mater Interfaces. 2019 Jan 9;11(1):1394-1401. doi: 10.1021/acsami.8b16628. Epub 2018 Dec 17.
To further advance polymer solar cells requires the fast evolution of π-conjugated materials as well as a better understanding of their structure-property relationships. Herein, we present three copolymers (PT1, PT2, PT3) made through tuning π-bridges (without any group, thiophene, and 3-hexylthieno[3,2- b]thiophene) between electron-rich (D: BDTT) and -deficient (A: BDD) units. The comparative studies reveal the unique correlation that the tune of π-bridge on the polymeric backbone governs the solid stacking and photovoltaic properties of resultant poly(BDTT- alt-BDD)s, which provide an effective way to deliver new and efficient polymer with feasible processability. That is, polymers with either twist zigzag backbone (PT1) or with linear coplanar backbone (PT2) result in inferior photovoltaic performance upon simple solution casting. Among them, PT3 with extended zigzag backbone and planar segments exhibits suitable processability and retains good efficiency in nonfullerene solar cells through a single-solvent cast without involving tedious treatments. This work illustrates that the tuning of the D-π-A polymer backbone facilitates efficient materials with feasible processability, promising for scale-up fabrication.
要进一步推动聚合物太阳能电池的发展，需要π共轭材料的快速发展以及对其结构-性能关系的更好理解。在此，我们展示了三种通过调节富电子（给体：BDTT）和缺电子（受体：BDD）单元之间的π桥（无任何基团、噻吩和3-己基噻吩并[3,2-b]噻吩）制备的共聚物（PT1、PT2、PT3）。对比研究揭示了一种独特的关联，即聚合物主链上π桥的调节控制了所得聚（BDTT-alt-BDD）s的固体堆积和光伏性能，这为提供具有可行加工性的新型高效聚合物提供了一种有效方法。也就是说，具有扭曲之字形主链（PT1）或线性共面主链（PT2）的聚合物在简单溶液浇铸时会导致较差的光伏性能。其中，具有延伸之字形主链和平坦链段的PT3表现出合适的加工性，并且通过单溶剂浇铸在非富勒烯太阳能电池中保持了良好的效率，而无需繁琐的处理。这项工作表明，D-π-A聚合物主链的调节有助于制备具有可行加工性的高效材料，有望实现规模化制造。
