Simulation and Optimization of FAPbI₃ Perovskite Solar Cells with a BaTiO₃ Layer for Efficiency Enhancement

Since the addition of BaTiO₃ in perovskite solar cells (PSCs) provides a more energetically favorable transport route for electrons, resulting in more efficient charge separation and electron extraction, in this work we experimentally prepared such a PSC and used a modeling approach to point out which simulation parameters have an influence on PSC characteristics and how they can be improved. We added a layer of BaTiO₃ onto the TiO₂ electron transport layer and prepared a PSC, which had an FTO/TiO₂/BaTiO₃/FAPbI₃/spiro-OMeTAD/Au architecture with a power conversion efficiency (PCE) of 11%. Further, we used the simulation program SCAPS-1D to investigate and optimize the device parameters (thickness of the BaTiO₃ and absorber layers, doping, and defect concentration) resulting in devices with PCEs reaching up to 15%, and even up to 20% if we assume an ideal structure with no interlayer defects. Our experimental findings and simulations in this paper highlight the promising interplay of multilayer TiO₂/BaTiO₃ ETLs for potential future applications in PSCs.