Constructing Controlled Vertical Gradient Morphology in Pseudo‐Planar Heterojunction Organic Photovoltaics via Self‐Assembled Interface Orthogonal Strategy

Abstract Precisely regulating vertically distributed morphology by blade‐coating process is crucial to realize high‐performance large‐scale pseudo‐planar heterojunction organic photovoltaics (OPVs). However, the thermodynamic motion and random diffusion of donor/acceptor (D/A) generated from the differences in surface energy and concentration during sequentially blade‐coating process will cause great challenges for obtaining ideal active layer morphology. Herein, this study have proposed a self‐assembled interface orthogonal strategy by introducing low surface energy guest (N2200) to form protective layer on PM6 surface, which counteracts erosion from orthogonal solution of acceptor to enhance continuity of D/A phases, thus promoting directional carrier migration and effectively suppressing energetic disorder. Finally, N2200‐modified device achieves the highest power conversion efficiency (PCE) of 19.86%, and large‐area module (16.94 cm 2 ) exhibits exceptional PCE (16.43%). This investigation presents innovative insights into morphology issue triggered by molecular motion and provides an effective method for air‐printing large‐scale OPVs with precisely controlled morphology based on non‐halogenated solvent.