A Vinylene‐Linker‐Based Polymer Acceptor Featuring a Coplanar and Rigid Molecular Conformation Enables High‐Performance All‐Polymer Solar Cells with Over 17% Efficiency. Issue 27 (29th May 2022)

• Record Type: Journal Article
• Authors: Yu, Han; Wang, Yan; Kim, Ha Kyung; Wu, Xin; Li, Yuhao; Yao, Zefan; Pan, Mingao; Zou, Xinhui; Zhang, Jianquan; Chen, Shangshang; Zhao, Dahui; Huang, Fei; Lu, Xinhui; Zhu, Zonglong; Yan, He
• Is Part Of: Advanced materials. Volume 34:Issue 27(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-05-29
• Subjects: all‐polymer solar cells -- polymer acceptors -- polymer conformation -- organic solar cells -- vinylene‐linkers; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202200361
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: State‐of‐art Y‐series polymer acceptors are typically based on a mono‐thiophene linker, which can cause some twisted molecular conformations and thus limit the performance of all‐polymer solar cells (all‐PSCs). Here, a high‐performance polymer acceptor based on vinylene linkers is reported, which leads to surprising changes in the polymers' molecular conformations, optoelectronic properties, and enhanced photovoltaic performance. It is found that the polymer acceptors based on thiophene or bithiophene linkers (PY‐T‐γ and PY‐2T‐γ) display significant molecular twisting between end‐groups and linker units, while the vinylene‐based polymer (PY‐V‐γ) exhibits a more coplanar and rigid molecular conformation. As a result, PY‐V‐γ demonstrates a better conjugation and tighter interchain stacking, which results in higher mobility and a reduced energetic disorder. Furthermore, detailed morphology investigations reveal that the PY‐V‐γ‐based blend exhibits high domain purity and thus a better fill factor in its all‐PSCs. With these, a higher efficiency of 17.1% is achieved in PY‐V‐γ‐based all‐PSCs, which is the highest efficiency reported for binary all‐PSCs to date. This work demonstrates that the vinylene‐linker is a superior unit to build polymer acceptors with more coplanar and rigid chain conformation, which is beneficial for polymer aggregation and efficient all‐PSCs. Abstract : A vinylene‐linker‐based polymer acceptor (PY‐V‐γ) with rigid and coplanar chain conformations is synthesized, exhibiting redshifted absorption and ordered packing. When employed in all‐polymer solar cells, the PY‐V‐γ‐based devices yield a higher efficiency of 17.1% than PY‐T‐γ‐ and PY‐2T‐γ‐based ones and exhibit robust mechanical stability in flexible devices, suggesting the potential for commercial application.