Dynamic hydrogen-bonding enables high-performance and mechanically robust organic solar cells processed with non-halogenated solvent

• Published in: Nature communications Vol. 16; no. 1; pp. 787 - 14
• Main Authors: He, Haozhe, Li, Xiaojun, Zhang, Jingyuan, Chen, Zekun, Gong, Yufei, Zhuo, Hongmei, Wu, Xiangxi, Li, Yuechen, Wang, Shijie, Bi, Zhaozhao, Song, Bohao, Zhou, Kangkang, Liang, Tongling, Ma, Wei, Lu, Guanghao, Ye, Long, Meng, Lei, Zhang, Ben, Li, Yaowen, Li, Yongfang
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 17.01.2025; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301/299/946; 639/4077/909/4101/4096/946; Charge efficiency; Charge transport; Chemical bonds; Chemistry; Clean energy; Commercialization; Efficiency; Energy; Energy charge; Energy conversion efficiency; Energy loss; Engineering; Ethyl esters; Humanities and Social Sciences; Hydrogen; Hydrogen bonding; Laboratories; Materials science; Molecular structure; Morphology; multidisciplinary; Phase distribution; Phase separation; Photovoltaic cells; Photovoltaics; Polymers; Robustness; Science; Science (multidisciplinary); Solar cells; Solvents; Stretchability; Thermal stability; Transport properties; Vertical distribution; Vertical separation; Xylene
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-55375-8

Developing active-layer systems with both high performance and mechanical robustness is a crucial step towards achieving future commercialization of flexible and stretchable organic solar cells (OSCs). Herein, we design and synthesize a series of acceptors BTA-C6, BTA-E3, BTA-E6, and BTA-E9, featuring the side chains of hexyl, and 3, 6, and 9 carbon-chain with ethyl ester end groups respectively. Benefiting from suitable phase separation and vertical phase distribution, the PM6:BTA-E3-based OSCs processed by o -xylene exhibit lower energy loss and improved charge transport characteristic and achieve a power conversion efficiency of 19.92% (certified 19.57%), which stands as the highest recorded value in binary OSCs processed by green solvents. Moreover, due to the additional hydrogen-bonding provided by ethyl ester side chain, the PM6:BTA-E3-based active-layer systems achieve enhanced stretchability and thermal stability. Our work reveals the significance of dynamic hydrogen-bonding in improving the photovoltaic performance, mechanical robustness, and morphological stability of OSCs. Developing high-performance and mechanically robust active-layer systems is crucial to commercializing flexible organic solar cells. Here, authors design small molecule acceptors with ethyl ester side chains and achieve certified efficiency of over 19% for mechanically robust devices.