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

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Chinese explanation / 中文解读

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Original 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.

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