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.