Numerical Insights Into Carrier Dynamics for ≈ 28% Efficient Perovskite Solar Cells via Surface‐Passivated FAPbI ₃ Absorber and Bilayer Electron Extraction Pathway

In the fast‐developing field of perovskite (PVT) solar cells (PSCs), concurrently accomplishing high efficiency and long‐term stability remains a critical impediment because of defect density and interfacial stability. Widely adopted technologies, namely the deployment of surface‐passivated hetero‐interfaces, can adequately confront these concerns via interfacial defect neutralization and streamlining hetero‐interface carrier extraction and transport. An extensive numerical modelling of devices featuring such strategic hetero‐interfaces is key to unveiling the carrier dynamics of potential PSC architectures ahead of expensive fabrication, and relevant studies remain unexplored. Thus, a comprehensive numerical modelling of a PSC employing a cesium iodide (CsI)‐surface passivated interface between the PVT absorber and the electron transport bilayer (SnO 2 /c‐TiO 2 ) evidenced ameliorated hetero‐interfacial band alignment. The effect of CsI incorporation on various pivotal layer parameters is rigorously investigated, benchmarking PSCs with CsI‐passivated interfaces (w/CsI) to their pristine analogues. The findings demonstrate a significant enhancement in power conversion efficiency of 27.61%, stemming from remarkable photovoltaic metrics. Furthermore, analysis of derived charge carrier recombination profiles and spectroscopic impedance analysis reveal a profound decline in hetero‐interfacial defect density due to CsI adaptation. These extensive numerical optimizations highlight the prospect of a well‐developed methodology for the expeditious emergence of robust and efficient PSCs for potential applications.