The incorporation of guest materials has been recognized as an effective strategy to further boost the photovoltaic performance. However, most guest materials introduced into ternary bulk heterojunctions are currently synthesized using multi-step Stille reactions, which typically suffer from poor atom-/step-economy, low cost-effectiveness and serious environmental problems. Consequently, guest materials synthesized through low-cost and eco-friendly tin-free approaches are highly required yet suffer from frequently poorly resolved issues. Herein, an asymmetric small-molecule guest donor oPhFO was designed and synthesized by a tin-free direct C–H activation strategy and incorporated into the classical PM6:BTP-ec9 host system. oPhFO exhibited a wide-bandgap and strong crystallinity, complementary absorption and cascade-like energy level alignment with the PM6:BTP-ec9 host system, which helps to improve the light-harvesting ability and open-circuit voltage. Moreover, oPhFO with a large dipole moment exhibited good miscibility with PM6, which finely regulated the pre-aggregation and crystallization kinetics of PM6 and BTP-ec9. This led to an optimized blend morphology and vertical phase separation, thereby achieving highly efficient exciton dissociation and charge transport. As a result, the PM6:oPhFO:BTP-ec9 ternary device achieved a champion power conversion efficiency of 19.5% with synchronously enhanced photovoltaic parameters. These results provide valuable guidelines for exploring tin-free guest materials while promoting the integration of green chemistry and clean energy.

中文翻译：

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由直接 C-H 芳基化衍生的宽带隙小分子客体供体实现的有机太阳能电池效率为 19.5%


客体材料的掺入已被认为是进一步提高光伏性能的有效策略。然而，目前引入三元本体异质结的客体材料大多采用多步Stille反应合成，通常存在原子/步骤经济性差、成本效益低和严重的环境问题。因此，迫切需要通过低成本且环保的无锡方法合成的客体材料，但经常遇到难以解决的问题。在此，通过无锡直接 C-H 激活策略设计和合成了不对称小分子客体供体o PhFO，并将其纳入经典的 PM6:BTP-ec9 宿主系统中。 o PhFO 表现出宽带隙和强结晶度、互补吸收以及与 PM6:BTP-ec9 宿主系统的级联能级对齐，这有助于提高光捕获能力和开路电压。此外，具有大偶极矩的o PhFO与PM6表现出良好的混溶性，可以精细调节PM6和BTP-ec9的预聚集和结晶动力学。这导致了优化的共混形态和垂直相分离，从而实现高效的激子解离和电荷传输。结果，PM6: o PhFO:BTP-ec9三元器件在同步增强的光伏参数下实现了19.5%的冠军功率转换效率。这些结果为探索无锡客体材料、同时促进绿色化学与清洁能源的融合提供了有价值的指导。