Coordination-Induced Dispersion of Covalent Organic Frameworks for Organic Solar Cells With 21.03% Efficiency.

Li, Mengdi; Xiao, Chengyi; Cheng, Yang; Gao, Zihao; Fan, Haiyun; Liang, Shijie; Kan, Jinglan; Jiang, Xiaoping et al. · Adv Mater · 2026

basic_science · Level V

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Abstract

Covalent organic frameworks (COFs) offer modular architectures and ordered π-channels ideal for organic solar cells (OSCs), yet their integration is hindered by poor solubility and deficient film-forming rheology. Herein, a coordination-induced dispersion strategy is reported using vanadium ions to unlock the potential of COFs as high-performance hole transport layers (HTLs). By intercalating vanadium ions into a novel COF (TBpy), the metal centers act as "molecular wedges," increasing interlayer spacing to transform the rigid framework into a highly dispersible, solution-processable precursor. This coordination refines film morphology and fine-tunes the electronic structure, establishing a seamless cascaded energy alignment. Consequently, OSCs utilizing TBpy-V HTLs achieve a high power conversion efficiency of 21.03% and extraordinary durability (T<sub>80</sub> lifetime of 20,097 h). Notably, the high conductivity of the framework renders the device thickness-insensitive, maintaining 17.80% PCE at 75 nm-a critical advantage for large-scale manufacturing. This study establishes metal-ion intercalation as a versatile tool for optimizing both the processability and electronic dynamics of crystalline optoelectronic materials.