The majority of host/guest materials used in organic solar cells (OSCs) are currently synthesized via Stille reaction, which suffers from poor atom/step economics, low cost-effectiveness, and environmental risks. Therefore, organic photovoltaic materials synthesized through low-cost and green methods are highly required. Here, an A-D-D-A type guest acceptor D-IDT was designed and synthesized by a tin-free direct C–H activation strategy and introduced into the classical D18:BTP-eC9 host system. Compared to the A-D-A type guest acceptor S-IDT, the D-IDT shows a greater π-conjugation but much weaker intermolecular interactions. Its low crystallinity results in good miscibility with the host acceptor BTP-eC9, which effectively promotes earlier assembly of BTP-eC9 and faster aggregation transition. This allows the formation of a smaller phase separation in the active layer, resulting in efficient exciton dissociation and charge transport. Moreover, the voltage loss of the OSCs device reduces by 18 mV when D-IDT is incorporated into the binary system. As a result, the efficiency of the D-IDT-controlled device is increased to 19.92% compared to the device with S-IDT (17.66%). This work provides valuable guidelines for the exploration of guest materials via the C–H activation reaction, while controlling the crystallization kinetics to fine-tune the assembly behavior of the host acceptor.

中文翻译：

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用于高效有机太阳能电池的直接 C-H 芳基化衍生的低结晶度客体受体


目前，有机太阳能电池 （OSC） 中使用的大多数主/客体材料都是通过 Stille 反应合成的，该反应存在原子/步骤经济性差、成本效益低和环境风险等问题。因此，对通过低成本和绿色方法合成的有机光伏材料提出了很高的要求。在这里，通过无锡直接 C-H 激活策略设计和合成了 A-D-D-A 型客体受体 D-IDT，并将其引入经典的 D18：BTP-eC9 宿主系统。与 A-D-A 型客体受体 S-IDT 相比，D-IDT 显示出更大的 π 偶联，但分子间相互作用要弱得多。其低结晶度导致与宿主受体 BTP-eC9 具有良好的混溶性，从而有效地促进了 BTP-eC9 的早期组装和更快的聚集转变。这允许在活性层中形成较小的相分离，从而实现有效的激子解离和电荷传输。此外，当 D-IDT 集成到二进制系统中时，OSCs 器件的电压损耗降低了 18 mV。因此，与采用 S-IDT 的设备 （17.66%） 相比，D-IDT 控制设备的效率提高了 19.92%。这项工作为通过 C-H 活化反应探索客体材料提供了有价值的指导，同时控制结晶动力学以微调宿主受体的组装行为。