Tuning terminal aromatics of electron acceptors to achieve high-efficiency organic solar cells

Herein, two new electron acceptors, BTTPC and BTTPC-Br, are developed through extending the conjugation of terminal electron accepting moieties with thiophene and bromine units. Such a structural design effectively improves the hole transfer of exciton dynamics in blends, revealing that BTTPC-Br and...

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Bibliographic Details
Published in:Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2019, Vol.7 (48), p.27632-27639
Main Authors: Qin, Ran, Wang, Di, Zhou, Guanqing, Yu, Zhi-Peng, Li, Shuixing, Li, Yuhao, Liu, Zhi-Xi, Zhu, Haiming, Shi, Minmin, Lu, Xinhui, Li, Chang-Zhi, Chen, Hongzheng
Format: Article
Language:English
Subjects:
Aromatic compounds
Bromine
Chemical synthesis
Conjugation
Electrons
Energy conversion efficiency
Excitons
Fabrication
Mixtures
Organic chemistry
Photovoltaic cells
Solar cells
Structural design
Structural engineering
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Summary:Herein, two new electron acceptors, BTTPC and BTTPC-Br, are developed through extending the conjugation of terminal electron accepting moieties with thiophene and bromine units. Such a structural design effectively improves the hole transfer of exciton dynamics in blends, revealing that BTTPC-Br and BTTPC based blends, in the presence of a smaller energetic offset as a driving force, exhibit faster hole transfer from acceptors to the polymeric donor interface, 4 times (BTTPC-Br) and 1.5 times (BTTPC) faster than 0.44 picoseconds of unmodified Y5. As a result, organic solar cells (OSCs) based on the BTTPC-Br acceptor, outperforming those of BTTPC:PBDB-T and Y5:PBDB-T, reach a power conversion efficiency of 15.22%, which is so far one of the highest among the single junction OSCs made with PBDB-T polymer donor. The structural tuning of non-fullerene acceptors with extended terminal aromatics enables faster hole transfer from the acceptor to the donor at smaller energy offsets, thereby achieving high efficiency in organic solar cells.
ISSN:2050-7488
2050-7496
DOI:10.1039/c9ta11285e