Nonfullerene polymer solar cells (PSCs) are fabricated by using one wide bandgap donor PBDB‐T and one ultranarrow bandgap acceptor IEICO‐4F as the active layers. One medium bandgap donor PTB7‐Th is selected as the third component due to the similar highest occupied molecular orbital level compared to that of PBDB‐T and their complementary absorption spectra. The champion power conversion efficiency (PCE) of PSCs is increased from 10.25% to 11.62% via incorporating 20 wt% PTB7‐Th in donors, with enhanced short‐circuit current (J_SC) of 24.14 mA cm⁻² and fill factor (FF) of 65.03%. The 11.62% PCE should be the highest value for ternary nonfullerene PSCs. The main contribution of PTB7‐Th can be summarized as the improved photon harvesting and enhanced exciton utilization of PBDB‐T due to the efficient energy transfer from PBDB‐T to PTB7‐Th. Meanwhile, PTB7‐Th can also act as a regulator to adjust PBDB‐T molecular arrangement for optimizing charge transport, resulting in the enhanced FF of ternary PSCs. This experimental result may provide new insight for developing high‐performance ternary nonfullerene PSCs by selecting two well‐compatible donors with different bandgap and one ultranarrow bandgap acceptor.

中文翻译：

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高效三元聚合物太阳能电池，具有两个兼容的供体和一个超窄带隙非富勒烯受体

非富勒烯聚合物太阳能电池（PSC）是通过使用一种宽带隙供体PBDB-T和一种超窄带隙受体IEICO-4F作为活性层来制造的。与PBDB-T及其互补的吸收光谱相比，由于具有相同的最高占据分子轨道能级，因此选择了一个中带隙供体PTB7-Th作为第三组分。通过在施主中掺入20 wt％的PTB7-Th，PSC的最佳功率转换效率（PCE）从10.25％提高到11.62％，短路电流（J _SC）提高到24.14 mA cm ^-2填充因子（FF）为65.03％。三元非富勒烯PSC的最高PCE值应为11.62％。PTB7-Th的主要贡献可以归结为由于PBDB-T到PTB7-Th的有效能量转移，改善了PBDB-T的光子收集和激子利用。同时，PTB7-Th还可以作为调节剂来调节PBDB-T的分子排列，以优化电荷传输，从而提高三元PSC的FF。通过选择两个带隙不同的良好相容的供体和一个窄带隙受体，该实验结果可能为开发高性能三元富勒烯PSC提供新的见识。