Solution-processed nonfullerene bulk-heterojunction (BHJ) polymer solar cells (PSCs), which are composed of polymer donors and organic acceptors, are proven to manifest promising performance and long-term stability. In this concise contribution, bithieno[3,4-c]pyrrole-4,6-dione (BiTPD), which is a TPD derivative but presents a large planar structure and strong electron-withdrawing ability, was used to construct a large-bandgap polymer donor PBiTPD. Results show that the polymer donor PBiTPD realized power conversion efficiency (PCE) as high as 14.2% in fullerene-free BHJ solar cells. Larger ionization potential value, more favorable face-on backbone orientation, and stronger crystallinity were concurrently obtained in PBiTPD. Correspondingly, improved and more balanced charge transportation; less nongeminate and trap-assisted recombination losses; and thus high fill factor (FF) of 67%, short-circuit current density (JSC) of 25.6 mA·cm-2, and high open-circuit voltage (VOC) of 0.83 V were concurrently achieved in PBiTPD-based devices. PBiTPD does clear the way for a novel and promising class of large-bandgap polymer donor candidates.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was financially supported by the National Natural Science Foundation of China (Nos. 21805097, 21671071, and 51521002), the Guangdong Natural Science Foundation (No. 2016A030310428), Guangdong Applied Science and Technology Planning Project (Nos. 2015B010135009 and 2017B090917002), and Guangzhou Science and Technology Foundation (No. 201904010361). The authors thank Jinwei Gao (SCNU), Xin Song (King Abdullah University of Science & Technology (KAUST)), Zhiguang Xu (SCNU), and Wei Wei (SCNU) for help in thin-film thickness, PESA, theoretical calculation, and PL measurements, respectively. The authors appreciate SCNU Analysis & Testing Center for technical support. This work was performed in part on the SAXS/WAXS beamline at the Australian Synchrotron, which is part of ANSTO.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.