From device physics to system performance: multiscale evaluation of Ba2AgBiBr6 lead-free perovskite solar cells.

Lead-free double-perovskite photovoltaic devices are gaining traction as environmentally preferable substitutes for lead-containing halide solar cells. This work conducts an extensive numerical assessment of the barium-based double-perovskite Ba2AgBiBr6 using SCAPS-1D, aiming to refine the device stack and elevate photovoltaic parameters. Six candidate electron transport layers (ETLs), such as CdS, SnS2, WS2, PCBM, TiO2, and C60, were systematically paired with nine candidate hole transport layers (HTLs), such as MoTe2, CuI, Cu2Te, MoS2, CBTS, CFTS, Spiro-MeOTAD, PEDOT:PSS, and P3HT, producing 54 distinct device permutations for parametric screening. Additionally, three front metal contacts (Al, Ag, Cu) and nine back metal contacts (Cu, Fe, C, Au, W, Ni, Pd, Pt, Se) were examined to evaluate contact influence on performance. The best-performing solar cell used CdS as ETL and MoTe2 as HTL, achieving a power conversion efficiency (PCE) of 24.42%, with open-circuit voltage (V OC) = 0.6 V, short-circuit current density (J SC) = 49.58 mA cm-2, and fill factor (FF) = 82%. Device-level results were ported into PVsyst to assess module behavior under realistic operating conditions. For a 72-cell module layout, the CdS-based module produced a P MPP of 509.85 W among the tested ETL variants. The joint SCAPS-1D with PVsyst methodology thus provides a pragmatic route for translating cell-scale optimizations into module-scale energy predictions.