Backbone Coplanarity Tuning of 1,4-Di(3-alkoxy-2-thienyl)-2,5-difluorophenylene-Based Wide Bandgap Polymers for Efficient Organic Solar Cells Processed from Nonhalogenated Solvent

• Published in: ACS applied materials & interfaces 2019-08, Vol.11 (34), p.31119-31128
• Main Authors: Liao, Qiaogan, Yang, Kun, Chen, Jianhua, Koh, Chang Woo, Tang, Yumin, Su, Mengyao, Wang, Yang, Yang, Yinhua, Feng, Xiyuan, He, Zhubing, Woo, Han Young, Guo, Xugang
• Format: Article
• Language: English
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.9b09692

Halogenated solvents are prevailingly used in the fabrication of nonfullerene organic solar cells (NF-OSCs) at the current stage, imposing significant restraints on their practical applications. By copolymerizing phthalimide or thieno­[3,4-c]­pyrrole-4,6-dione (TPD) with 1,4-di­(3-alkoxy-2-thienyl)-2,5-difluorophenylene (DOTFP), which features intramolecular noncovalent interactions, the backbone planarity of the resulting DOTFP-based polymers can be effectively tuned, yielding distinct solubilities, aggregation characters, and chain packing properties. Polymer DOTFP-PhI with a more twisted backbone showed a lower degree of aggregation in solution but an increased film crystallinity than polymer DOTFP-TPD. An organic thin-film transistor and NF-OSC based on DOTFP-PhI, processed with a nonhalogenated solvent, exhibited a high hole mobility up to 1.20 cm2 V–1 s–1 and a promising power conversion efficiency up to 10.65%, respectively. The results demonstrate that DOTFP is a promising building block for constructing wide bandgap polymers and backbone coplanarity tuning is an effective strategy to develop high-performance organic semiconductors processable with a nonhalogenated solvent.