Herein, asymmetric isomer effects are systematically explored by designing and synthesizing two benzo[c][1,2,5]thiadiazole (BT)-fused nonacyclic electron acceptors. By changing from BP6T-4F to asymmetric ABP6T-4F, significantly enhanced dielectric constant and inhibited excessive molecular aggregation and unfavorable edge-on orientation could be achieved. The reduced exciton binding energy also facilitates a more efficient dissociation process in PM6:ABP6T-4F compared to PM6:BP6T-4F with the same energy offset. Moreover, the weaker crystallization behavior enables a significantly enhanced miscibility between PM6 and ABP6T-4F than that between PM6 and BP6T-4F, which leads to an optimized micromorphology with smooth surface, suitable domain size, and ordered π–π stacking. Organic solar cells (OSCs) based on PM6:ABP6T-4F achieve a 15.8% power conversion efficiency (PCE), which is remarkably higher than that of PM6:BP6T-4F-based OSCs (6.4%). Furthermore, ternary devices are also fabricated considering good compatibility between ABP6T-4F and CH1007 to deliver a PCE over 17%. This study reveals the effectiveness and great potential of asymmetric isomerization strategy in regulating molecular properties, which will provide guidance for the future design of non-fullerene acceptors.

中文翻译：

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苯并[c][1,2,5]噻二唑-稠合非环受体中的不对称异构体效应：显着提高光伏性能的介电常数和分子结晶度控制

本文通过设计合成二苯并[ c]系统地探索了不对称异构体效应。][1,2,5] 噻二唑 (BT) 稠合非环电子受体。通过将 BP6T-4F 改为不对称 ABP6T-4F，可以显着提高介电常数并抑制过度分子聚集和不利的边缘取向。与具有相同能量偏移的 PM6:BP6T-4F 相比，降低的激子结合能也促进了 PM6:ABP6T-4F 中更有效的解离过程。此外，较弱的结晶行为使得 PM6 和 ABP6T-4F 之间的混溶性比 PM6 和 BP6T-4F 之间的混溶性显着提高，从而导致具有光滑表面、合适的域尺寸和有序 π-π 堆积的优化微形态。基于 PM6:ABP6T-4F 的有机太阳能电池 (OSC) 实现了 15.8% 的功率转换效率 (PCE)，明显高于基于 PM6:BP6T-4F 的 OSC (6.4%)。此外，考虑到 ABP6T-4F 和 CH1007 之间的良好兼容性，还制造了三元器件，以提供超过 17% 的 PCE。该研究揭示了不对称异构化策略在调节分子性质方面的有效性和巨大潜力，将为未来非富勒烯受体的设计提供指导。