南开大学陈永胜团队揭示了非富勒烯受体的中心单元氟化使高效有机太阳能电池的效率超过18%。相关研究成果发表在2022年7月27日出版的国际知名学术期刊《德国应用化学》。

受体末端的卤化已被证明能显著提高有机太阳能电池的功率转换效率。尽管很少有研究，但如果在最先进的Y系列受体的中心单元上进行卤化，也可以预期类似的重要结果，因为已经证明中心单元对分子填充有显著影响。

该文中，研究人员设计/合成了一对受体CH₆和CH₄，其特征是具有共轭扩展控制吩嗪中心单元，含/不含氟化。CH₆上的额外氟化导致分子相互作用和结晶度增强，纤维网络形态优越，并改善共混膜中的电荷生成/传输，因此，与CH₄的16.49%相比，CH₆基二元OSCs的PCE更高，为18.33%。

该工作为Y系列分子的进一步结构优化提供了一个具有新中心位点的激动人心的平台，以提供性能更好的OSCs，并揭示了中心单元氟化的有效性。

附：英文原文

Title: Central Unit Fluorination of Non-Fullerene Acceptor Enables Highly Efficient Organic Solar Cells with Over 18% Efficiency

Author: Hongbin Chen, Huazhe Liang, Ziqi Guo, Yu Zhu, Zhe Zhang, Zhixiang Li, Xiangjian Cao, Haohui Wang, Wanying Feng, Yalu Zou, Lingxian Meng, Xiaoyun Xu, Bin Kan, Chenxi Li, Zhaoyang Yao, Xiangjian Wan, Zaifei Ma, Yongsheng Chen

Issue&Volume: 2022-07-27

Abstract: Halogenations on terminal of acceptors have been proven to render dramatical improvements in power conversion efficiencies (PCEs) of organic solar cells (OSCs). Despite rare studies, similar significant results could be also expected if halogenations on central units of the state-of-the-art Y-series acceptors is applied, given that central units have been proved to impact molecular packings significantly. Herein, a pair of acceptors, CH6 and CH4, featured with conjugation-extended control phenazine central unit with/out fluorination, have been designed/synthesized. The extra fluorination on CH6 leads to an enhanced molecular interaction and crystallinity, superior fibrillar network morphology and improved charge generation/transport in blend films, thus affording a higher PCE of 18.33% for CH6-based binary OSCs comparing to that of 16.49% for CH4. Our work provides an exciting platform with the new central site for further structural optimization on Y-series molecules to afford better-performed OSCs and reveals the effectiveness of fluorination on central units.

DOI: 10.1002/anie.202209580

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202209580