Decoding Interfacial Charge‐Carrier Dynamics in Integrated Perovskite/Organic Solar Cells via Numerical Modeling

Integrated perovskite/organic solar cells (I‐POSCs), which combine narrow‐bandgap organic absorbers with single‐junction perovskite cells, offer a new strategy for extending light absorption while maintaining the high open‐circuit voltage inherent to perovskites. Despite significant progress, I‐POSC efficiency is constrained by complex interfacial charge‐carrier dynamics at the perovskite/organic interface. A comprehensive theoretical framework based on drift‐diffusion simulations is developed to investigate charge‐carrier processes at the perovskite/organic interface. This stepwise analysis establishes critical links between carrier transport phenomena and device performance metrics. While Type‐II perovskite/organic alignment promotes photocurrent generation through efficient current extraction, and reverse Type‐II alignment preserves photovoltage via beneficial quasi‐Fermi level bending, the fill factor becomes the dominant performance‐limiting factor in the Type‐I transition regime due to moderate energetic barriers. Bimolecular recombination within the organic bulk heterojunction is identified as the primary loss mechanism in current I‐POSC devices, as opposed to interfacial trap‐assisted recombination. Suppressing this recombination channel can lead to substantial performance improvements. Further predictions indicate that the ideal performance of I‐POSCs remains confined within the detailed‐balance limits of the single‐junction OSC subcell. This work provides a unified physical understanding of the unusual behaviors in I‐POSCs and offers the I‐POSC community clear insights into their true potential.