Multi-component copolymerized donors (MCDs) represent an advantageous electron-donating material for optimizing the efficiency of flexible organic solar cells (f-OSCs). However, the inherent randomness in typical MCD structures often leads to non-uniform structures, thereby compromising intermolecular assembly and molecular organization. Consequently, achieving a balance between high efficiency and adequate stretchability poses a significant challenge. In this study, a novel series of sequential-block MCDs with high molecular weight has been developed. The regular polymer skeleton and ideal molecular stacking resulting from the sequential block arrangement in the PM6-Cl_0.8-b-D18-Cl_0.2-TCl donor material led to a stabilized power conversion efficiency (PCE) of 18.55% for rigid and 17.21% for flexible binary OSCs. Additionally, promising crack-onset strain (COS) values of 32.02% and 22.58% have been observed in pristine and blend films, respectively, striking a balance between photovoltaic and mechanical properties. Notably, the PCE of the optimal ternary device based on PM6-Cl_0.8-b-D18-Cl_0.2-TCl also reached 19.57%. Furthermore, the incorporation of the flexible functional group 1,4-bis(thiophen-2-ylthio) butane (BTB) further enhanced the mechanical stretchability. The COS values of 40.29% and 25.38% have been obtained in the flexible spacer-block MCD PM6-Cl_0.8-b-D18-Cl_0.2-BTB pristine film and the corresponding blended film, respectively, marking some of the highest values achieved by MCD-based binary OSCs. This study showcases the innovative potential of sequential-block MCDs incorporating flexible spacers in the development of high-performance and mechanically robust f-OSCs for the first time.

中文翻译：

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灵活的间隔块多组分共聚供体使有机太阳能电池具有超过 40% 的裂纹起始应变


多组分共聚供体 （MCD） 是一种有利的电子供体材料，可用于优化柔性有机太阳能电池 （f-OSC） 的效率。然而，典型 MCD 结构中固有的随机性通常会导致结构不均匀，从而影响分子间组装和分子组织。因此，在高效率和足够的可拉伸性之间取得平衡是一项重大挑战。在这项研究中，已经开发了一系列具有高分子量的新型顺序块 MCD。PM6-Cl 0.8-b-D18-Cl _0.2-TCl 供体材料中的顺序块状排列产生的规则聚合物骨架和理想的分子堆叠导致刚性 OSC 的稳定功率转换效率 （PCE） 为 18.55%，柔性二元 OSC 的稳定功率转换效率 （PCE） 为 17.21%。此外，在原始薄膜和混合薄膜中观察到的有希望的裂纹起始应变 （COS） 值分别为 32.02% 和 22.58%，在光伏和机械性能之间取得了平衡。值得注意的是，基于 PM6-Cl0.8-b-D18-Cl _0.2-TCl 的最佳三元器件的 PCE 也达到了 19.57%。此外，柔性官能团 1,4-双（噻吩-2-基硫代）丁烷 （BTB） 的掺入进一步增强了机械拉伸性。在柔性间隔块 MCD PM6-Cl0.8-b-D18-Cl _0.2-BTB 原始薄膜和相应的混合薄膜中分别获得了 40.29% 和 25.38% 的 COS 值，标志着基于 MCD 的二元 OSC 达到的一些最高值。 本研究首次展示了在开发高性能和机械坚固的 f-OSC 中采用柔性垫片的顺序块 MCD 的创新潜力。