Rationalizing the Influence of Tunable Energy Levels on Quantum Efficiency to Design Optimal Non?Fullerene Acceptor?Based Ternary Organic Solar Cells

Non-fullerene acceptor (NFA)-based ternary bulk heterojunction solar cells (TSC) are the most efficient organic (OSCs) today due to their broader absorption and quantum efficiencies (QE) often surpassing those of corresponding binary blends. We study how energetics driving charge transfer at electron donor:electron (D/A) interfaces impact QE in blends PBDB-T-2F donor with several pairs lower bandgap NFAs. As blends, ionization energy offset between ({\Delta}IE) controls maximizes for {\Delta}IE > 0.5 eV. However, is not controlled by individual NFAs IEs but average, weighted blending ratio. Using this property, we improved a PBDB-T-2F:IEICO blend that had an insufficient generation adding deep IE third component: IT-4F. Combining two enables optimize D/A alignment cells' without molecular engineering.