Utilization of Diamagnetic Force Introduced by External Magnetic Fields for Printing Scalable Organic Photovoltaics

The photovoltaic performance and stability of scalable organic solar cells (OSCs) are significantly governed by the micromorphology, molecular interactions, and stacking behavior of the active layer. As the device area increases, these effects are amplified, making long-range morphological control of small-molecule acceptors challenging and frequently leading to performance degradation. Herein, a non-contact and size-insensitive magnetic-field-assisted printing strategy is developed, which modulates the chemical environment of molecular end groups during film formation and enhances intermolecular interactions, thereby regulating the molecular stacking behavior. These collectively improve the film homogeneity, reduce the defect density, and minimize the performance loss in large-area devices. Finally, the optimal pseudo-planar heterojunction OSCs, fabricated via air atmosphere printing, achieve a champion power conversion efficiency (PCE) of 20.23%. Furthermore, large-area binary modules with an aperture area of 25.00 cm² retain an optimized PCE of 16.70%, underscoring their strong potential for scalable production. Overall, this work proposes a universal approach for printing high-quality photoactive films and provides a valuable framework for the collaborative optimization of organic electronic devices.