The π-expansion of non-fullerene acceptors is a promising method for boosting the organic photovoltaic performance by allowing the fine-tuning of electronic structures and molecular packing. In this work, highly efficient organic solar cells (OSCs) are fabricated using a 2D π-expansion strategy to design new non-fullerene acceptors. Compared with the quinoxaline-fused cores of AQx-16, the π-expanded phenazine-fused cores of AQx-18 induce more ordered and compact packing between adjacent molecules, affording an optimized morphology with rational phase separation in the blend film. This facilitates efficient exciton dissociation and inhibited charge recombination. Consequently, a power conversion efficiency (PCE) of 18.2% with simultaneously increasing V_oc, J_sc, and fill factor is achieved in the AQx-18-based binary OSCs. Significantly, AQx-18-based ternary devices fabricated via a two-in-one alloy acceptor strategy exhibit a superior PCE of 19.1%, one of the highest values ever reported for OSCs, along with a high V_oc of 0.928 V. These results indicate the importance of the 2D π-expansion strategy for the delicate regulation of the electronic structures and crystalline behaviors of the non-fullerene acceptors to achieve superior photovoltaic performance, aimed at significantly promoting further development of OSCs.

中文翻译：

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由具有良好电子和聚集结构的二维共轭非富勒烯受体实现效率超过 19% 的有机太阳能电池

非富勒烯受体的π扩展是一种通过微调电子结构和分子堆积来提高有机光伏性能的有前景的方法。在这项工作中，使用二维π扩展策略来设计新的非富勒烯受体来制造高效有机太阳能电池（OSC） 。与 AQx-16 的喹喔啉稠合核相比， AQx-18 的π扩展吩嗪稠合核诱导相邻分子之间更加有序和紧凑的堆积，从而在共混膜中提供具有合理相分离的优化形态。这有利于有效的激子解离并抑制电荷复合。因此，基于 AQx-18 的二元 OSC 实现了18.2% 的功率转换效率 (PCE)，同时增加了V _oc、J _{sc和填充因子。}值得注意的是，通过二合一合金受体策略制造的基于 AQx-18 的三元器件表现出 19.1% 的优异 PCE（这是 OSC 有史以来报道的最高值之​​一），以及 0.928 V 的高 V oc 。这些_{结果表明二维}π扩展策略对于非富勒烯受体的电子结构和晶体行为的精细调控以实现优异的光伏性能的重要性，旨在显着促进OSC的进一步发展。