Bipolar-resistive switching characteristics in lead-free inorganic double-halide perovskite-based memory devices

Owing to the increasing demands of high-density data storage double-halide perovskite-based resistive random access memory (RRAM) have recently emerged as a promising candidate in the forefront of next-generation optoelectronic memory applications. The ionic motion-based quick switching is the key feature of this kind of material, which plays a significant role in resistive switching (RS) applications. Recently, lead-free tin-based double-halide perovskites have been considered as favourable material due to their superior stability, functionality and eco-friendly nature. Here, we report the synthesis of cesium tin (IV) iodide (Cs₂SnI₆) perovskites. X-ray diffraction (XRD) pattern of the as-synthesized perovskite confirms the formation of Cs₂SnI₆ material. The crystallographic data corroborate the formation of a pure cubic phase, free of any other phase at room temperature. We also studied optical properties of the sample by using the ultraviolet–visible (UV) spectra and photoluminescence (PL) spectra. A broadband at around 580 nm is observed in the UV−Vis absorption spectra. The optical band gap of the sample is found to be 1.68 eV. Cs₂SnI₆ perovskite exhibited intense PL emission at ~540 nm. In this work, to fabricate a flexible Al/Cs₂SnI₆/ITO-PET memory device, we used Cs₂SnI₆ film as a switching layer and the device exhibits bipolar RS characteristics.