Long‐Term Field Screening by Mobile Ions in Thick Metal Halide Perovskites: Understanding Saturation Currents

Metal halide perovskite-based semiconductor devices with micrometer-to-millimeter-thick perovskite layers show a current response upon polarization which evolves up to several hours, transiting regimes. This is the case of X-ray detectors where use absorber perovskites produces instabilities in dark reverse saturation hindering signal processing. Even though these phenomena are often attributed electronic–ionic conductivity and interface perovskites, proper theoretical description missing. Herein, numerical simulation study reproduces main experimental trends explains origin some apparently-always-increasing transients thick samples. The mobile ion concentration mobility correlated three transport regimes interpretation parameterization provided time terms ionic screening electric field toward interfaces. final steady-state under found as diffusion-limited electronic current, results from abrupt depletion proportional Debye length vicinity contact. conclusions suggest material optimization contact interfaces pathway reduce long times devices.