Research Paper: Analytical model for interface recombination limited ideality factors in p-i-n perovskite solar cells
Scientific Summary
This study presents a novel analytical model for elucidating the influence of nonradiative interface recombination on the open-circuit voltage (VOC) and ideality factor (nid) in p-i-n perovskite solar cells (PSCs). The main goal was to clarify how interface recombination, a dominant loss channel, affects these critical device parameters. Key findings include the derivation of analytical expressions demonstrating that in devices dominated by interface recombination, VOC is limited by the electrical potential loss across the charge transport layer, and nid becomes dependent on the dielectric properties (thickness, dielectric constant) of these layers. The model also reveals that nid strongly increases with higher mobile ion densities and slower voltage scan speeds. These findings are crucial for understanding and mitigating nonradiative losses.
Publication Details
Sandberg, O.J., Kumar, M., Stolterfoht, M., Neher, D. and Armin, A. (2025), Analytical model for interface recombination limited ideality factors in p-i-n perovskite solar cells. APL Energy, 3: 036107. https://doi.org/10.1063/5.0286898.
Fluxim Tools Used
SETFOS was utilized for numerical drift-diffusion simulations. SETFOS was instrumental in substantiating the derived analytical model by simulating J-V curves and the open-circuit voltage as a function of light intensity for various scenarios, including different transport layer thicknesses and mobile ion densities. The simulations considered interface Shockley-Read-Hall (SRH) recombination via mid-gap states at the perovskite/ETL interface, along with specific device parameters for electrodes, perovskite, HTL, and ETL.
Why it Matters
This research provides a fundamental and systematic understanding of how interface recombination dictates VOC and nid in p-i-n PSCs, offering crucial insights into how to minimize nonradiative losses by manipulating charge transport layer properties. The findings offer potential explanations for conflicting ideality factor observations in literature. SETFOS played a vital role by validating the analytical framework through robust numerical simulations, thereby strengthening the theoretical conclusions and accelerating the rational design of more efficient and stable perovskite solar cells.