Thermally Activated “Cold” Holes Overcome Recombination Limits in Single‐Component Organic Solar Cells With 15.6% Efficiency

Abstract

ABSTRACT Single‐component organic solar cells (SCOSCs) based on double‐cable conjugated polymers offer unparalleled morphological stability compared to bulk‐heterojunction systems, but their efficiencies are severely bottlenecked by rapid geminate recombination. While the intrinsic donor–acceptor proximity in these polymers generates ultralong‐lived charge‐transfer (CT) states (>5 ns), these “cold” carriers are traditionally viewed as an energetic trap. Here, we report a thermodynamic strategy that converts this extended temporal window into a resource for thermally activated charge extraction. By engineering an interfacial energy ladder using a D18 polymer layer with a precise 0.02 eV highest occupied molecular orbital (HOMO) offset, we demonstrate that long‐lived holes can be thermally promoted and selectively harvested. This active energy management mechanism successfully outcompetes non‐radiative recombination loss, simultaneously elevating the open‐circuit voltage, short‐circuit current, and fill factor. Consequently, the optimized devices achieve a record‐breaking power conversion efficiency of 15.65%. This work establishes a new paradigm for organic photovoltaics: demonstrating that long‐lived excited states, previously considered a fundamental limitation, can be strategically harnessed as a thermal activation reservoir to overcome thermodynamic recombination losses.