With the power conversion efficiency of binary polymer solar cells dramatically improved, the thermal stability of the small-molecule acceptors raised the main concerns on the device operating stability. Here, to address this issue, thiophene-dicarboxylate spacer tethered small-molecule acceptors are designed, and their molecular geometries are further regulated via the thiophene-core isomerism engineering, affording dimeric TDY-α with a 2, 5-substitution and TDY-β with 3, 4-substitution on the core. It shows that TDY-α processes a higher glass transition temperature, better crystallinity relative to its individual small-molecule acceptor segment and isomeric counterpart of TDY-β, and a more stable morphology with the polymer donor. As a result, the TDY-α based device delivers a higher device efficiency of 18.1%, and most important, achieves an extrapolated lifetime of about 35000 hours that retaining 80% of their initial efficiency. Our result suggests that with proper geometry design, the tethered small-molecule acceptors can achieve both high device efficiency and operating stability.

随着二元聚合物太阳能电池功率转换效率的显着提高，小分子受体的热稳定性成为器件运行稳定性的主要关注点。在这里，为了解决这个问题，设计了噻吩-二羧酸盐间隔物系链小分子受体，并通过噻吩核异构工程进一步调节其分子几何结构，提供具有 2、5-取代的二聚体 TDY-α 和 TDY-β在核心上有 3、4 个取代。它表明 TDY-α 处理更高的玻璃化转变温度，相对于其单个小分子受体链段和 TDY-β 的异构对应物更好的结晶度，以及与聚合物供体更稳定的形态。因此，基于 TDY-α 的器件提供了 18.1% 的更高器件效率，最重要的是，实现约 35000 小时的推断寿命，并保持其初始效率的 80%。我们的结果表明，通过适当的几何设计，系链小分子受体可以实现高器件效率和操作稳定性。