Effect of bisalkylthio side chains on benzo[1, 2-b:4, 5-b′]dithiophene-based polymers for organic solar cells. (March 2017)

• Record Type: Journal Article
• Authors: Deng, Ping; Yu, Jiangsheng; Yin, Xinxing; Geng, Yongliang; Zhou, Baojing; Zhang, Fujun; Tang, Weihua
• Is Part Of: Dyes and pigments. Volume 138(2017)
• Page Start: 47
• Page End: 55
• Publication Date: 2017-03
• Subjects: Bisalkylthio side chain -- Benzo[1, 2-b:4, 5-b′]dithiophene -- Polymer solar cells -- Conjugated polymer -- Power conversion efficiency; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2016.11.015
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: The length and conformation of solubilizing side chains in π-conjugated polymers impact polymers' self-assembling properties in thin-film devices. To reveal the effect of different bisalkylthio side chains, four copolymers containing bisalkylthio side chain modifying two-dimensional benzo[1, 2- b :4, 5 -b ′]dithiophene (BDT) donor with (5, 6-difluoro-4, 7-di(thiophen-2-yl)benzo[ c ][1, 2, 5]thiadiazole (BDff) acceptor have been developed and studied in this report. The different absorption maxima ( λ max ) ofPBDTT-DS1-BTff, PBDTT-DS2-BTff, PBDTT-DS3-BTff andPBDTT-DS4-BTff are 578, 574, 591 and 594 nm in CHCl3 solution, respectively, indicating different aggregation behaviors. The devices based onPBDTT-DS1-BTff didn't reveal high PCEs due to its poor miscibility with PC71 BM compared to those with other polymers. The devices blendingPBDTT-DS2-BTff with PC71 BM exhibited a highest PCE of 5.82%, with an enhanced J SC of 11.06 mA cm −2, a V OC of 0.92 V and a FF of 57.2%. This work demonstrates that suitable side chain lengths in π-conjugated polymers are of great significance in optimizing the performance of polymers based solar cells. Graphical abstract: Highlights: The synthesis of bisalkylthiobenzo[1, 2- b :4, 5- b ′]dithiophene based polymers. The electrochemical characterization and molecular simulation of polymers. The effect of bisalkylthio side chains on BDT polymer properties. The highest PCE of 5.82% forPBDTT-DS2-BTff based OPVs.