Zhu Yuhang, Ma Yunlong, Liu Li, Cai Dongdong, Wang Jin-Yun, Shi Haiting, Zheng Qingdong
State Key Laboratory of Structure Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, 350002, China.
College of Chemistry, Fuzhou University, Fuzhou, 350116, China.
Angew Chem Int Ed Engl. 2024 Dec 9;63(50):e202411155. doi: 10.1002/anie.202411155. Epub 2024 Oct 17.
As the simplest oligomeric acceptors, dimerized acceptors (DAs) are easier to synthesize, and more importantly, they can retain good intermolecular interaction and photovoltaic properties of their parent small-molecule acceptors (SMAs). Nevertheless, currently most efficient DAs are derived from banana-shaped acceptors and they might suffer from inferior device stability with high diffusion coefficients. Herein, we design and synthesize two planar DAs (DMT-FH and DMT-HF) by bridging two linear-shaped M-series SMAs with a thiophene unit. The effects of fluorination position on the diffusion coefficients, power conversion efficiencies (PCEs) and stability of the DAs are systematically studied. Our results suggest that DMT-HF with fluorination on the ending indanone groups shows enhanced intermolecular interactions, improved PCE and stability compared with the counterpart (DMT-FH) with fluorination on the central indanone groups. Further optimization on the DMT-HF-based devices yields an outstanding PCE of 17.17 %, which is the highest among all linear-shaped SMA-based DAs. Notably, with the low diffusion coefficient (3.36×10 cm s) of DMT-HF, the resulting device retains over 93 % of the initial PCE after 5000 h of continuous heating at 85 °C, suggesting its excellent thermal stability. The results highlight the importance of intermolecular interaction and fluorination for achieving efficient and stable polymer solar cells.
作为最简单的寡聚受体，二聚受体（DAs）易于合成，更重要的是，它们能够保留其母体小分子受体（SMAs）良好的分子间相互作用和光伏性能。然而，目前大多数高效的DAs都源自香蕉形受体，并且它们可能因高扩散系数而导致器件稳定性较差。在此，我们通过用噻吩单元桥接两个线性M系列SMA来设计并合成了两种平面DAs（DMT-FH和DMT-HF）。系统研究了氟化位置对DAs的扩散系数、功率转换效率（PCE）和稳定性的影响。我们的结果表明，与在中心茚满酮基团上氟化的对应物（DMT-FH）相比，在末端茚满酮基团上氟化的DMT-HF表现出增强的分子间相互作用、更高的PCE和稳定性。对基于DMT-HF的器件进行进一步优化后，获得了17.1７%的出色PCE，这在所有基于线性SMA的DAs中是最高的。值得注意的是，由于DMT-HF的低扩散系数（3.36×10 cm s），在85°C连续加热5000小时后，所得器件保留了超过93%的初始PCE，表明其具有出色的热稳定性。这些结果突出了分子间相互作用和氟化对于实现高效稳定的聚合物太阳能电池的重要性。
