A research team from China has proposed a novel interfacial buffering strategy for pseudo-planar heterojunction (PPHJ) organic solar cells (OSCs) to improve device stability and fabrication reliability. By incorporating a highly crystalline polymer called D18 as a buffer layer between the donor and acceptor layers, the PM6/D18/L8-BO-based device achieved a superior power conversion efficiency of 19.80%, surpassing conventional devices. Further modifications with a non-fullerene small-molecule acceptor led to an efficiency of 20.21%, one of the highest reported for PPHJ OSCs. The study, published in the Chinese Journal of Polymer Science, offers practical insights for enhancing device performance and morphology regulation in organic solar cells with controlled vertical phase separation morphology.