Suppressed Ion Migration along the In-Plane Direction in Layered Perovskites

Ion migration in a three-dimensional (3D) perovskite is the source of many unique phenomena such as photocurrent hysteresis and a giant switchable photovoltaic effect and can also accelerate the degradation of perovskite-based electronic devices. Here we report the observation of suppressed ion migration along the in-plane direction of layered perovskites by studying the conductivity of layered single-crystal perovskites at varied temperatures. Large-area layered perovskite thin single crystals are synthesized by the space-confined method. The absence of ion migration in these layered perovskites can be explained by an increase in the energy required to form an ion vacancy, compared to 3D perovskites. The suppressed ion migration in layered perovskites indicates that they have intrinsically better stability under an electric field and may contribute to the improved perovskite stability in devices made of layered perovskite through the reduction of ion diffusion-induced perovskite degradation or corrosion of charge transport layers and electrodes.