Two dependent working mechanisms enables efficient ternary polymer solar cells with broad compositional tolerance

Abstract Decades of rapid development of polymer solar cells, more and more researchers shift from the direction of pursuing higher power conversion efficiency (PCE) to investigate the properties that satisfy the future commercialization processing conditions. In this work, an efficient D1:D2:A nonfullerene ternary polymer solar cells (PSCs) was fabricated by introducing PM6 in PBTA-PS:ITIC system. With complementary light absorption, structure compatibility, more favorable face-on orientation, optimized morphology and tuned energy levels, the ternary PSCs achieve an enhanced PCE of 11.91% with enhanced short circuit current density (JSC) of 18.58 mA cm−2 and fill factor (FF) of 67.70%, which are higher than that of binary solar cells. It is useful to mention that the ternary devices exhibit with broad compositional tolerance and device stability, which satisfy the large-scale commercialization fabrication conditions. After systematically analysis, two dependent working mechanisms are illustrated in the ternary devices, including FRET channel and charge transfer channel, which benefit the energy transfer and excitons dissociation. Therefore, this work demonstrated a facile method to fabricate efficient two donors ternary PSCs with broad compositional tolerance, higher stability and two dependent working mechanisms, which further promote the commercialization of PSCs.