Polymerized Small Molecular Acceptor with Branched Side Chains for All Polymer Solar Cells with Efficiency over 16.7%

Li, Yun; Song, Jiali; Dong, Yicai; Jin, Hui; Xin, Jingming; Wang, Shijie; Cai, Yunhao; Jiang, Lang; Ma, Wei; Tang, Zheng; Sun, Yanming

doi:10.1002/adma.202110155

DOE OSTI · 1981353

Polymerized Small Molecular Acceptor with Branched Side Chains for All Polymer Solar Cells with Efficiency over 16.7%

Li, Yun·Song, Jiali·Dong, Yicai·Jin, Hui·Xin, Jingming·Wang, Shijie·Cai, Yunhao·Jiang, Lang·Ma, Wei·Tang, Zheng·Sun, Yanming

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Abstract

The power conversion efficiencies (PCEs) of small molecule acceptor (SMA)-based organic solar cells have already exceeded 18%. However, the development of polymer acceptors still lags far behind their SMA counterparts mainly due to the lack of efficient polymer acceptors. In this work, a series of polymer acceptors named PY-X (with X being the branched alkyl chain) are designed and synthesized by employing the same central core with the SMA L8-BO but with different branched alkyl chains on the pyrrole motif. It is found that the molecular packing of SMA-HD featuring 2-hexyldecyl side chain used in the synthesis of PY-HD is similar to L8-BO, in which the branched alkyl chains lead to condensed and high-order molecular assembly in SMA-HD molecules. When combined with PM6, PY-HD-based all polymer solar cell (all-PSC) exhibits a high PCE of 16.41%, representing the highest efficiency for the binary all-PSCs. Moreover, the side-chain modification on the pyrrole site position further improves the performance of the all-PSCs, and the PY-DT-based device delivers a new record high efficiency of 16.76% (certified as 16.3%). The work provides new insights for understanding the structure–property relationship of polymer acceptors and paves a feasible avenue to develop efficient conjugated polymer acceptors.

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14 SOLAR ENERGY all polymer solar cells branched side chain efficiency polymer acceptors small molecular acceptors

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Li, Yun, Song, Jiali, Dong, Yicai, Jin, Hui, Xin, Jingming, Wang, Shijie, Cai, Yunhao, Jiang, Lang, Ma, Wei, Tang, Zheng, Sun, Yanming. 2022-01-28. Polymerized Small Molecular Acceptor with Branched Side Chains for All Polymer Solar Cells with Efficiency over 16.7%. https://doi.org/10.1002/adma.202110155

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