1. A Near-infrared Non-fullerene Acceptor with Thienopyrrole-expanded Benzo[1,2-b:4,5-b′]dithiophene Core for Polymer Solar Cells.
- Author
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Chen, Zhen, Ma, Shan-Shan, Zhang, Kai, Hu, Zhi-Cheng, Yin, Qing-Wu, Huang, Fei, and Cao, Yong
- Subjects
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THIOPHENES , *SOLAR cells , *FULLERENE polymers , *INTRAMOLECULAR charge transfer , *OPEN-circuit voltage , *SHORT-circuit currents , *POLYMERS - Abstract
A near-infrared non-fullerene acceptor (NFA) BDTIC, based on thienopyrrole-expanded benzo[1,2-b:4,5-b′]dithiophene unit (heptacyclic S,N-heteroacene) as core, is designed and synthesized. The aromatic pyrrole ring with strong electron-donating ability in the core enhances the intramolecular charge transfer effect, finely tunes the optical bandgap and absorption profile of BDTIC, and thus results in a narrowed optical bandgap (Egopt) of 1.38 eV and a near-infrared absorption to 900 nm. When BDTIC is paired with donor polymer PBDB-T to fabricate organic solar cells, the optimized device achieves a best power conversion efficiency of 12.1% with a short-circuit current density of 20.0 mA·cm−2 and an open-circuit voltage of 0.88 V. The photovoltaic performance benefits from the broad absorption, weak bimolecular recombination, efficient charge separation and collection, and favorable blend morphology. This work demonstrates that thienopyrrole-expanded benzo[1,2-b:4,5-b′]dithiophene unit (heptacyclic S,N-heteroacene) is a promising building unit to construct high-performance NFAs by enhancing the intramolecular charge transfer effect, broadening absorption as well as maintaining good intermolecular stacking property. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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