Well-regulated Structures Featured Giant-molecule Acceptors Enable Long-term Stability and High-Performance Binary Organic Solar Cells

The well-defined structures featured giant-molecule acceptors (GMAs) can exhibit unique properties of small-molecule acceptors and polymers simultaneously, and the consecutive innovations in materials design have enabled GMAs-based organic solar cells (OSCs) to possess outstanding devices power conversion efficiency (PCE) over 19% and extended long-term stability. Here, through systematically selecting the numbers and positions of selenium atom, π-spacer linking units and the outermost conjugate ring of central core of monomers, four novel GMAs are successfully synthesized, GMA-SSS, GMA-SSeS, GMA-SeSSe and GMA-SeSeSe. Surprisingly, PM6:GMA-SSeS-based OSC yields the highest PCE of 19.37% with remarkably open current voltage of 0.917 V with reduced voltage loss (ΔE3 = 0.246 eV), and excellent fill factor of 77.12%. Furthermore, when devices annealed at 100 °C, the PM6:GMA-SSeS and PM6:GMA-SSS-based OSCs exhibit remarkably extended t80% lifetimes of 5600 and 5250 h, respectively. Our work indicates that the selenium substituted regulation of GMAs structures in linking units and monomers is a valuable approach to obtain high-performance and long-term stability devices at the same time, shedding light on the further development of GMAs-based OSCs.