Compatibilizer‐Mediated Aggregation Suppression Enables High‐Performance Organic Photovoltaic Modules Processed From Green Solvents

Prolonged film formation from green solvents often induces excessive aggregation. This remains a critical challenge for the scalable fabrication of high‐performance organic photovoltaic (OPV) modules. Herein, we show that a rationally designed giant molecule, D‐IO, can serve as an effective third component to suppress aggregation. Employing PM6:BTP‐eC9 as a representative host blend, D‐IO effectively modulates donor‐acceptor interactions by enhancing their compatibility, thereby promoting cooperative assembly and inhibiting the uncontrolled growth of large aggregates during film formation. This yields a well‐defined fibrillar network morphology while preserving desired molecular packing and charge transport pathways. Consequently, small‐area devices processed with the green solvent o ‐xylene achieve a champion power conversion efficiency (PCE) of 19.71%. More importantly, this strategy is readily applicable to large‐area fabrication. Blade‐coated modules with active areas of 9.97 and 26.6 cm 2 achieved PCEs of 17.26% and 15.49%, respectively. This work provides an effective morphological regulator for high‐performance OPV modules processed from green solvents.