Multi‐dimensional Synergistic Regulation Enables Low Energy Loss and 20.23% Efficiency in Sequentially Deposited Ternary Organic Solar Cells ^†

Comprehensive Summary

Despite recent breakthroughs in organic solar cell (OSC) efficiency, the trade‐off between broadening spectral response and minimizing non‐radiative energy loss remains a critical bottleneck. While ternary strategies and sequential deposition (SqP) each offer unique benefits, their single‐dimensional optimization often fails to balance efficient photon harvesting with ideal vertical phase separation. Herein, we report a multi‐dimensional synergistic regulation strategy by incorporating polymer acceptor PYF‐T‐ o into the SqP‐processed PM6/eC9 system, where PYF‐T‐ o establishes a cascade energy‐level alignment and forms an alloy‐like acceptor phase with eC9. This unique microstructure broadens spectral absorption, lowers the donor/acceptor surface energy difference, accelerates crystallization kinetics (reducing nucleation time by 60 ms), and refines phase separation. Consequently, the ternary devices exhibit balanced carrier mobilities, ultrafast charge extraction (0.197 μs), and prolonged carrier lifetime (4.54 μs), effectively suppressing trap‐assisted recombination. The energetic disorder is reduced to 23.43 meV, minimizing non‐radiative voltage loss from 0.218 eV to 0.205 eV. By utilizing a 2PACz self‐assembled monolayer, the optimized device achieves a high power conversion efficiency of 20.23% and demonstrates enhanced photostability with the T ₈₀ lifetime extended from 117 h to 260 h. This work establishes a robust paradigm for synchronously reducing energy loss and enhancing device performance via multi‐dimensional synergistic regulation.