Perovskite Ion Migration & J-V Hysteresis

Metal-halide perovskite solar cells are famous for a quirk that ordinary silicon cells don't share: their measured efficiency depends on how fast — and in which direction — you sweep the voltage. This simulator renders the microscopic cause directly: mobile iodide-vacancy ions inside the perovskite layer drift under the applied field and pile up at the transport-layer interfaces, partially screening the voltage the diode actually experiences. Because that ionic polarization lags the sweep, the forward and reverse legs of the J-V curve trace different paths, opening a hysteresis loop whose width you can control with scan rate, ion mobility, vacancy density and temperature — the same knobs real device physicists use to diagnose and suppress hysteresis.