Optimized active layer morphology toward efficient and polymer batch insensitive organic solar cells

• Published in: Nature communications Vol. 11; no. 1; pp. 2855 - 9
• Main Authors: Weng, Kangkang, Ye, Linglong, Zhu, Lei, Xu, Jinqiu, Zhou, Jiajia, Feng, Xiang, Lu, Guanghao, Tan, Songting, Liu, Feng, Sun, Yanming
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 05.06.2020; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301; 639/624; Active control; Cell morphology; Cytology; Deposition; Drying; Efficiency; Fabrication; Fullerenes; Humanities and Social Sciences; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Morphology; multidisciplinary; Photovoltaic cells; Polymers; Science; Science (multidisciplinary); Solar cells; Spin coating
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-16621-x

Morphology control in laboratory and industry setting remains as a major challenge for organic solar cells (OSCs) due to the difference in film-drying kinetics between spin coating and the printing process. A two-step sequential deposition method is developed to control the active layer morphology. A conjugated polymer that self-assembles into a well-defined fibril structure is used as the first layer, and then a non-fullerene acceptor is introduced into the fibril mesh as the second layer to form an optimal morphology. A benefit of the combined fibril network morphology and non-fullerene acceptor properties was that a high efficiency of 16.5% (certified as 16.1%) was achieved. The preformed fibril network layer and the sequentially deposited non-fullerene acceptor form a robust morphology that is insensitive to the polymer batches, solving a notorious issue in OSCs. Such progress demonstrates that the utilization of polymer fibril networks in a sequential deposition process is a promising approach towards the fabrication of high-efficiency OSCs. Reliably controlling the morphology in organic solar cells is desired for up-scaling. Here Weng et al. combine the advantages of the fibril network donor and the state of the art Y6 acceptor in a two-step approach to deliver a high efficiency of 16% without batch-to-batch variation.