High‐performance nonfullerene ternary organic solar cells (OSCs) with two polymer donors are less frequently reported because of the limited numbers of efficient polymer donors with good compatibility. Herein, a wide‐bandgap polymer P1 with a deep‐lying highest occupied molecular orbital (HOMO) level is incorporated as the third component into the benchmark PM6:Y6 binary system to fabricate ternary OSCs. The introduction of P1 not only leads to extended absorption coverage and forms a cascade‐like energy level alignment but also shows excellent compatibility with PM6, resulting in a favorable morphology in the ternary blend. More importantly, P1 possesses a deeper HOMO level (−5.6 eV) than most well‐known donor polymers, which enables resulting ternary OSCs with an improved open‐circuit voltage. As a result, the optimized ternary OSCs with 40 wt% P1 in donors achieve a power conversion efficiency (PCE) of 16.2% with a small nonradiative recombination loss of 0.23 eV, which is among the highest values of ternary OSCs based on two polymer donors. In addition, the ternary OSCs show a broad composition tolerance with a high PCE of over 14% throughout the whole blend ratios. These results provide an effective approach to fabricate efficient ternary OSCs by synergizing two wide‐bandgap polymer donors.

中文翻译：

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两个兼容的聚合物供体，使三元有机太阳能电池具有较小的无辐射能量损失和宽泛的组成公差

带有两个聚合物供体的高性能非富勒烯三元有机太阳能电池（OSC）报道较少，因为具有良好相容性的有效聚合物供体数量有限。在此，将具有深处最高占据分子轨道（HOMO）水平的宽带隙聚合物P1作为第三组分纳入基准PM6：Y6二元体系中，以制备三元OSC。P1的引入不仅导致吸收范围扩大，并形成级联状能级排列，而且与PM6表现出优异的相容性，从而在三元共混物中形成良好的形态。更重要的是，P1具有比大多数众所周知的供体聚合物更深的HOMO能级（-5.6 eV），这使得生成的三元OSC具有改善的开路电压。结果是，供体中P1含量为40 wt％的优化三元OSC的功率转换效率（PCE）为16.2％，非辐射复合损失很小，为0.23 eV，这是基于两个聚合物供体的三元OSC的最高值。此外，三元OSC在整个混合比例中显示出宽泛的成分耐受性，PCE超过14％。这些结果通过协同两个带隙宽的聚合物供体，为制造有效的三元OSC提供了有效的方法。