Achieving 19.41% efficiency in thickness-insensitive all-polymer solar cells via interface modifier-mediated morphological modulation

Abstract

This study introduces a dual-compatibility third component as an interfacial modifier to precisely regulate the active layer morphology of bulk heterojunction organic solar cells (BHJ-OSCs). This approach successfully suppresses excessive phase separation, thus significantly enhancing the performance of thick-film devices. This interface-styling strategy enhances donor–acceptor interactions, optimizes the vertical phase separation morphology, extends the exciton diffusion length, improves the exciton dissociation efficiency, facilitates efficient charge transport, and effectively suppresses trap-assisted recombination. The ternary device based on PM6:PCN3:PY-IT achieved a power conversion efficiency (PCE) of 19.41%, which was much higher than that of the PM6:PY-IT binary system (18.67%). The device maintains excellent performance at an active layer thickness of 200 nm, achieving a high PCE of 18.25%. This study demonstrates the significance of using dually compatible molecules for interface modification in all-polymer solar cells (all-PSCs), providing theoretical guidance for the fabrication of high-performance thick-film devices.