Innovative molecule design strategy holds promise for the development of next‐generation acceptor materials for efficient organic solar cells with low non‐radiative energy loss (ΔEnr). In this study, we designed and prepared three novel acceptors, namely BTP‐Biso, BTP‐Bme and BTP‐B, with sterically structured triisopropylbenzene, trimethylbenzene and benzene as side chains inserted into the shoulder of the central core. The progressively enlarged steric hindrance from BTP‐B to BTP‐Bme and BTP‐Biso induces suppressed intramolecular rotation and altered the molecule packing mode in their aggregation states, leading to significant changes in absorption spectra and energy levels. By regulating the intermolecular π‐π interactions, BTP‐Bme possesses relatively reduced non‐radiative recombination rate and extended exciton diffusion lengths. The binary device based on PB2:BTP‐Bme exhibits an impressive power conversion efficiency (PCE) of 18.5% with a low ΔEnr of 0.19 eV. Furthermore, the ternary device comprising PB2:PBDB‐TF:BTP‐Bme achieves an outstanding PCE of 19.3%. The molecule design strategy in this study proposed new perspectives for developing high‐performance acceptors with low ΔEnr in OSCs.

中文翻译：

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通过空间位阻优化分子堆积以减少有机太阳能电池中的非辐射复合

创新的分子设计策略有望开发具有低非辐射能量损失（ΔEnr）的高效有机太阳能电池的下一代受体材料。在本研究中，我们设计并制备了三种新型受体，即BTP-Biso、BTP-Bme和BTP-B，其立体结构的三异丙苯、三甲苯和苯作为侧链插入到中心核的肩部。从 BTP-B 到 BTP-Bme 和 BTP-Biso 的空间位阻逐渐增大，导致分子内旋转受到抑制，并改变了聚集状态下的分子堆积模式，导致吸收光谱和能级发生显着变化。通过调节分子间π-π相互作用，BTP-Bme具有相对降低的非辐射复合率和延长的激子扩散长度。基于 PB2:BTP-Bme 的二元器件表现出令人印象深刻的 18.5% 功率转换效率 (PCE) 和 0.19 eV 的低 ΔEnr。此外，由 PB2:PBDB-TF:BTP-Bme 组成的三元器件实现了 19.3% 的出色 PCE。本研究中的分子设计策略为开发 OSC 中低 ΔEnr 的高性能受体提出了新的视角。