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 similar to 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.