Modulating the self-assembly process of polymer donors is crucial to acquire an ideal morphology of the photoactive layer for efficient photovoltaics, however, this always requires complicated chemical synthesis or comprehensive physical treatments. In this work, a facile morphology optimization method was realized by irradiating polymer solutions with a 365 nm UV-light for achieving enhanced intermolecular ordering of polymer donors. Fourier transform infrared spectroscopy and Raman spectroscopy reveal that light irradiation can disrupt the aromatic conformation of polymers and induce the formation of a rigid quinone structure. Synchrotron X-ray diffraction suggests that the rigid qunione skeleton improves the planarity of polymers to form compact aggregates with enhanced π–π stacking in their pristine and blend thin films with non-fullerene acceptor L8-BO. As a result, both PM6:L8-BO and D18:L8-BO based devices exhibited enhanced carrier transport and suppressed recombination, leading to power conversion efficiency (PCE) enhancements from 18.8% to 19.7% and from 18.9% to 19.6%. The versatility of this strategy is also verified using more polymer donors including PTB7-Th and PBDB-T. Impressively, the D18:PM6:L8-BO ternary system delivered a maximum PCE of 19.9%, which is among the highest value of single-junction organic solar cells.

中文翻译：

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聚合物供体的光诱导醌构象，有机太阳能电池效率达到 19.9%

调节聚合物供体的自组装过程对于获得高效光伏的光活性层的理想形态至关重要，然而，这总是需要复杂的化学合成或全面的物理处理。在这项工作中，通过用 365 nm 紫外光照射聚合物溶液，实现了一种简便的形态优化方法，以增强聚合物供体的分子间有序性。傅里叶变换红外光谱和拉曼光谱表明，光照射可以破坏聚合物的芳香构象并诱导刚性醌结构的形成。同步加速器X射线衍射表明，刚性醌骨架改善了聚合物的平面度，从而在其原始和与非富勒烯受体L8-BO共混薄膜中形成具有增强π-π堆积的致密聚集体。结果，基于 PM6:L8-BO 和 D18:L8-BO 的器件均表现出增强的载流子传输和抑制的复合，导致功率转换效率 (PCE) 从 18.8% 提高到 19.7%，从 18.9% 提高到 19.6%。该策略的多功能性也通过使用更多的聚合物供体（包括 PTB7-Th 和 PBDB-T）得到了验证。令人印象深刻的是，D18:PM6:L8-BO三元系统的最大PCE达到19.9%，这是单结有机太阳能电池的最高值之​​一。