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

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 (T₈₀ 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.