Quantifying charge transportation for stable organic solar cells with a novel aluminum acetylacetone electron collection layer

摘要

Elucidating charge transportation mechanism for low-temperature solution-processed charge collection layer is crucial for efficient and stable organic solar cells (OSCs). Herein, we present a facile method to fabricate Al (acac)_3 film and integrate it as electron collection layer (ECU in OSCs. The PM6:Y6-based OSCs with Al(acac)_3 ECL achieve a higher efficiency of 16.12% as compared to the control devices with a 10.90% efficiency. Importantly, the Al(acac)_3-based devices present superior operational stability, which retains 60% of the initial PCE after 100 h continuous illumination in air. Investigations on optics and carrier recombination dynamics reveal that the improved performance benefits from high up to 98% transparency of Al(acac)_3 ECL, optimized interfacial contact and enhanced exciton dissociation ratio from 85.10% to 97.51%. Further studies on quantified interface resistances during the internal charge transfer indirectly reflect the enhancement of stability. These results highlight the promising prospect of Al(acac)_3 ECL in processing compatible, operationally stable high efficiency OSCs.