An Isomeric Solid Additive Enables High‐Efficiency Polymer Solar Cells Developed Using a Benzo‐Difuran‐Based Donor Polymer

作者：Lu Chen, Jicheng Yi, Ruijie Ma, Lu Ding, Top Archie Dela Peña, Heng Liu, Jian Chen, Cuifen Zhang, Chaoyue Zhao, Wen Lu, Qi Wei, Bin Zhao, Huawei Hu, Jiaying Wu, Zaifei Ma, Xinhui Lu, Mingjie Li, Guangye Zhang, Gang Li, He Yan · 发表于：Advanced Materials · 年份：2023 · DOI：10.1002/adma.202301231 · 被引用次数：83 · 研究领域：Organic Electronics and Photovoltaics、Perovskite Materials and Applications、Conducting polymers and applications

Currently, nearly all high-efficiency organic photovoltaic devices use donor polymers based on the benzo-dithiophene (BDT) unit. To diversify the choices of building blocks for high-performance donor polymers, the use of benzo-difuran (BDF) units is explored, which can achieve reduced steric hindrance, stronger molecular packing, and tunable energy levels. In previous research, the performance of BDF-based devices lagged behind those of BDT-based devices. In this study, a high efficiency (18.4%) is achieved using a BDF-based polymer donor, which is the highest efficiency reported for BDF donor materials to date. The high efficiency is enabled by a donor polymer (D18-Fu) and the aid of a solid additive (2-chloronaphthalene), which is the isomer of the commonly used additive 1-chloronaphthalene. These results revealed the significant effect of 2-chloronaphthalene in optimizing the morphology and enhancing the device parameters. This work not only provides a new building block that can achieve an efficiency comparable to dominant BDT units but also proposes a new solid additive that can replace the widely used 1-chloronaphthalene additive.