Suppressing Co‐Crystallization of Halogenated Non‐Fullerene Acceptors for Thermally Stable Ternary Solar Cells

.H. and S.H.K.P. contributed equally to this work. The authors acknowledge the King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) under OSR-2018-CPF-4106 and the Knut and Alice Wallenberg Foundation through the project “Mastering Morphology for Solution-borne Electronics” (2016.0059) for funding. M.C.-Q. and A.H. acknowledge the European Research Council (ERC) for funding under grant agreement no. 648901. The authors thank MCIU for a Ramon y Cajal contract, Ikerbasque Foundation for the Fellow program (J.M) and grants Ref. PGC2018-094620-A-100, SEV-2015-0496 and PGC2018-095411-B-100. L.Y. thanks the National Nature Science Foundation of China (NSFC 21905185) for financial support. The authors thank the National Synchrotron Light Source II, Brookhaven National Lab (Suffolk, Upton, New York, USA) for beamtime.