Side-chain engineering for efficient non-fullerene polymer solar cells based on a wide-bandgap polymer donor. Issue 19 (26th April 2017)

• Record Type: Journal Article
• Authors: Fan, Qunping; Su, Wenyan; Guo, Xia; Wang, Yan; Chen, Juan; Ye, Chennan; Zhang, Maojie; Li, Yongfang
• Is Part Of: Journal of materials chemistry. Volume 5:Issue 19(2017)
• Page Start: 9204
• Page End: 9209
• Publication Date: 2017-04-26
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c7ta02075a
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : Non-fullerene polymer solar cells based on a wide-bandgap polymer, PSBZ, exhibited a PCE of up to 10.5% with a high J sc of 19.0 mA cm −2 . Abstract : In this work, a new wide-bandgap polymer, PSBZ, based on thienyl substituted benzodithiophene (BDTT) as the donor unit and difluorobenzotriazole (BTz-2F) as the acceptor unit was synthesized for photovoltaic applications. Compared to the analogous polymer J61 with linear dodecylthio side chains in the BDTT unit and a long 2-hexyldecyl side chain in BTz-2F, PSBZ possesses branched 2-butyloctyl side chains to increase steric hindrance of the BDTT unit and a short 2-butyloctyl side chain to decrease steric hindrance of the BTz-2F unit for more efficient charge separation and transport in the devices. As a result, PSBZ exhibited stronger π–π interaction and smaller stacking spacing leading to a higher extinction coefficient of 1.48 × 10 5 cm −1 and a high hole mobility of 8.56 × 10 −3 cm 2 V −1 s −1 . Compared to the analogous polymer J61 with a power conversion efficiency (PCE) of 9.53% and a short-circuit current density ( J sc ) of 17.43 mA cm −2, the PSBZ:ITIC-based polymer solar cells yielded a higher PCE of 10.5% with a higher J sc of 19.0 mA cm −2 . The results show that our design strategy is successful for improving photovoltaic performance by side chain engineering.