Novel Fused-Ring Electron Acceptors Based on Double Electron-Deficient Central Core for High-Performance Organic Solar Cells.

Authors

Jin Li, Jiayi Cheng, Yuang Fu, Jinyang Yu, Mingtao Liu, Shuzhen Liao, Weilin Zhou, Yuanyuan Jiang, Peipei Zhu, Meng Tao, Ting Yang, Xiaopeng Xu, Feng Liu, Xinhui Lu, Haiming Zhu, Xunfan Liao, Yiwang Chen

Published in

Angewandte Chemie (International ed. in English). Nov 05, 2026. Epub Nov 05, 2026.

Abstract

Rapid advances in A-DA'D-A fused-ring electron acceptors have significantly boosted organic solar cells (OSCs), yet non-radiative energy loss (ΔE₃) remains a persistent bottleneck, and reliance on single electron-deficient cores limits further molecular diversification. Herein, we report CBT-4F, a novel acceptor featuring a double electron-deficient bis([1,2,5]thiadiazolo)[3,4-c:3',4'-g]carbazole (CBT) core constructed via stepwise intramolecular Cadogan reductive cyclization. This synthetic strategy circumvents the challenges of carrying multiple nitro groups through key cross-coupling steps and offers an extensible route to multi-electron-deficient-core acceptors. Compared with the benchmark acceptor Y6, CBT-4F exhibits extended π-conjugation, increased backbone curvature, a lower average molecular electrostatic potential, and a distinct packing motif. These coupled molecular and solid-state characteristics, together with optimized blend morphology and recombination behavior, are associated with significantly suppressed ΔE₃ in PM6:CBT-4F devices (0.220 vs. 0.262 eV for PM6:Y6). Benefiting from a wider photovoltaic bandgap and reduced ΔE₃, PM6:CBT-4F achieves a power conversion efficiency (PCE) of 19.02% with a high open-circuit voltage (V_OC) of 0.923 V, substantially outperforming the PM6:Y6 counterpart (17.63%, 0.834 V). Furthermore, incorporating CBT-4F as a third component into the PM6:BTP-eC9 system boosts the ternary PCE to 20.57%. This work establishes CBT-4F as a high-performance molecular platform and expands synthetic accessibility to multi-electron-deficient-core acceptors.

PMID:
42989717
Bibliographic data and abstract were imported from PubMed on 06 Nov 2026.

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