Oligothiophene Additive‐Assisted Morphology Control and Recombination Suppression Enable High‐Performance Organic Solar Cells

作者：Wenting Liang, Lu Chen, Zhibo Wang, Zhengxing Peng, Liangxiang Zhu, Chung Hang Kwok, Han Yu, Wenzhao Xiong, Tongzi Li, Ziyue Zhang, Yufei Wang, Yaozu Liao, Guangye Zhang, Huawei Hu, Yiwang Chen · 发表于：Advanced Energy Materials · 年份：2024 · DOI：10.1002/aenm.202303661 · 被引用次数：83 · 研究领域：Organic Electronics and Photovoltaics、Conducting polymers and applications、Perovskite Materials and Applications

Abstract Tuning the morphology through processing additives represents one of the most promising strategies to boost the performance of organic solar cells (OSCs). However, it remains unclear how oligothiophene‐based solid additives influence the molecular packing and performance of OSCs. Here, two additives namely 2T and 4T, are introduced into state‐of‐the‐art PM6:Y6‐based OSCs to understand how they influence the film formation process, nanoscale morphology, and the photovoltaic performance. It is found that the 2T additive can improve the molecular packing of both donor polymer and non‐fullerene acceptor, resulting in lower Urbach energy and reduced energy loss. Furthermore, the blend film with 2T treatment displays enhanced domain purity and a more favorable distribution of the acceptor and donor materials in the vertical direction, which can enhance charge extraction efficiency while simultaneously suppressing charge recombination. Consequently, OSCs processed with 2T additive realize a promising efficiency of 18.1% for PM6:Y6‐based devices. Furthermore, the general applicability of the additive is demonstrated, and an impressive efficiency of 18.6% for PM6:L8‐BO‐based OSCs is achieved. These findings highlight that the uncomplicated oligothiophenes have excellent potential in fine‐adjustment of the active layer morphology, which is crucial for the future development of OSCs.