Peng Zhongxiang, Xian Kaihu, Cui Yong, Qi Qingchun, Liu Junwei, Xu Ye, Chai Yubo, Yang Chunming, Hou Jianhui, Geng Yanhou, Ye Long
School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin, 300350, China.
State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033, China.
Adv Mater. 2021 Dec;33(49):e2106732. doi: 10.1002/adma.202106732. Epub 2021 Oct 11.
Top-performance organic solar cells (OSCs) consisting of conjugated polymer donors and nonfullerene small molecule acceptors (NF-SMAs) deliver rapid increases in efficiencies. Nevertheless, many of the polymer donors exhibit high stiffness and small molecule acceptors are very brittle, which limit their applications in wearable devices. Here, a simple and effective strategy is reported to improve the stretchability and reduce the stiffness of high-efficiency polymer:NF-SMA blends and simultaneously maintain the high efficiency by incorporating a low-cost commercial thermoplastic elastomer, polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS). The microstructure, mechanical properties, and photovoltaic performance of PM6:N3 with varied SEBS contents and the molecular weight dependence of SEBS on microstructure and mechanical properties are thoroughly characterized. This strategy for mechanical performance improvement exhibits excellent applicability in some other OSC blend systems, e.g., PBQx-TF:eC9-2Cl and PBDB-T:ITIC. More crucially, the elastic modulus of such complex ternary blends can be nicely predicted by a mechanical model. Therefore, incorporating thermoplastic elastomers is a widely applicable and cost-effective strategy to improve mechanical properties of nonfullerene OSCs and beyond.
由共轭聚合物供体和非富勒烯小分子受体（NF-SMA）组成的高性能有机太阳能电池（OSC）的效率迅速提高。然而，许多聚合物供体表现出高刚性，小分子受体非常脆，这限制了它们在可穿戴设备中的应用。在此，报道了一种简单有效的策略，通过加入低成本的商用热塑性弹性体聚苯乙烯-嵌段-聚（乙烯-无规-丁烯）-嵌段-聚苯乙烯（SEBS）来提高高效聚合物：NF-SMA共混物的拉伸性并降低其刚性，同时保持高效率。对具有不同SEBS含量的PM6:N3的微观结构、机械性能和光伏性能以及SEBS对微观结构和机械性能的分子量依赖性进行了全面表征。这种改善机械性能的策略在一些其他OSC共混体系中表现出优异的适用性，例如PBQx-TF:eC9-2Cl和PBDB-T:ITIC。更关键的是，这种复杂三元共混物的弹性模量可以通过一个力学模型很好地预测。因此，加入热塑性弹性体是一种广泛适用且具有成本效益的策略，可用于改善非富勒烯OSC及其他材料的机械性能。
