Fig. 5: Simulations of lead-tin perovskite device behavior at varying J–V scan rates.

a PCE values extracted from backward and forward J–V scans with varying scan rates of a lead-tin perovskite device using a PEDOT:PSS HTL and b of a device using a PTAA HTL, after 0 and 19 h of encapsulated aging under 65 °C and simulated full-spectrum sunlight (76 mW cm⁻²) irradiance under open-circuit conditions (solid lines). The overlaid dotted lines show PCE values extracted from simulated J–V scans, modeled using the Ionmonger software for the same device architectures. Simulations were carried out for a range of perovskite bulk charge carrier lifetimes (τ_bulk) and mobile iodine vacancy densities (N_ion) shown in Fig. S15, with the best fits to experimental data shown here (corresponding parameter values are detailed in the legend). Dark lines represent parameters extracted from the initial reverse scans (decreasing in voltage), and pale lines represent the subsequent forward scan (increasing in voltage). c Simulated J–V curves modeled using the SCAPS−1D software for a lead-tin perovskite device using a PEDOT:PSS HTL, showing the impact of variation in the background hole density p₀ in the perovskite bulk. Dotted lines show the measured J–V curves for a device with the same architecture resulting from a very fast (752 V s⁻¹) scan, after 0 and 288 h of encapsulated aging under 65 °C and simulated full-spectrum sunlight (76 mW cm⁻²) irradiance under open-circuit conditions. Equivalent data is show in (d) for a device using a PTAA HTL and simulating variation in the background hole density p₀ in the perovskite bulk, in (e) for a device using a PEDOT:PSS HTL and simulating variation in the deep trap density in the perovskite bulk, and (f) for a device using a PTAA HTL and simulating variation in the deep trap density in the perovskite bulk.