Dissecting the structure-stability relationship of Y-series electron acceptors for real-world solar cell applications

• DOI: 10.1016/j.joule.2023.07.003
• Publication Date: 2023-07-24T14:38:50Z
• Authors: Han Xu; Jianhua Han; Si Chen; Ye Liu; Luis Huerta Herna...; Jules Bertrandie; Maxime Babics; Shahidul Alam; Diego Rosas Villalva; Sri Harish Kumar ...; Julien Gorenflot; Christoph Herok; Nicolas Ramos; Joel Troughton; Anirudh Sharma; Todd B. Marder; Bernd Engels; Jaime Martin; Stefaan De Wolf; Frédéric Laquai; Derya Baran
• Keywords: 621; 01 natural sciences; 0104 chemical sciences

Despite striking progress toward improving the photovoltaic (PV) performance of organic solar cells (OSCs) with recent Y-series non-fullerene acceptors (Y-NFAs), knowledge about their outdoor performance under real-world conditions and photodegradation mechanisms remains elusive, which is urgently needed to close the lab-to-fab gap of OSCs. Herein, for the first time, we study the structure-outdoor-stability relationship of Y-NFAs. We show that Y-NFAs with long internal side-chains exhibit high energy barriers for photoisomerization, and fluorinated end-groups can enhance the structural confinement to inhibit the photodegradation pathway and thereby improve device stability. Furthermore, the performance loss of Y-NFA-based OSCs under illumination is mainly driven by increased trap-assisted recombination over time. The structure-stability correlation and demonstration of outdoor performance of these state-of-the-art Y-NFA cells provided in this study highlight molecular engineering of device stability control to minimize power output losses in real-world climates. ; This publication is based upon work supported by the King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) under award no. OSR-CARF/CCF-3079 and award no. OSR-CRG2018-3746. We acknowledge the use of the KAUST Solar Center and the support from its staff. J.H. thanks the Alexander von Humboldt Foundation for a Postdoctoral Fellowship. D.B. acknowledges her daughter Ada for being an inspiration for the work on A-D-A structures.