Evolution of V_OC, J_SC, and FF for simulated degradation mechanisms among the cells studied. (a) Formation of deep defects in the perovskite, (b) reduction of hole mobility in the perovskite, (c) increase of series resistance. For each case, ∼100 evolutions are simulated. The average is shown in red, and the shaded area represents the 95% confidence interval. The isolated spike in panel (c) arises from a single simulation (numerical artefact) and does not affect the mean trend.