Flexible and lead-free halide perovskite ReRAM: Toward sustainable and adaptive memory devices

Halide perovskite-based resistive random-access memory (ReRAM), a next-generation non-volatile memory option, has attracted a lot of attention due to the search for environmentally friendly and adaptive electronics. Recent developments in flexible ReRAM and in lead-free halide perovskite-based memory devices are compiled in this paper, with an emphasis on electrical performance, switching mechanisms, stability-enhancing techniques, and structural design. Halide perovskites' natural advantages-such as their low working voltage, fast switching speed, and solution processability-make them attractive for incorporation into flexible platforms including neuromorphic computers, wearable electronics, and implanted devices. These devices exhibit fast switching, low operating voltages (<1 V), and high ON/OFF ratios (>10 6 ), making them promising for low-power applications. The operating voltages of devices that use MAPbI 3 and CsPbBr 3 are less than 1 V, and their ON/OFF ratios are greater than 10 6 . Performance deterioration brought on by mechanical deformation and exposure to the environment is still a major problem, though. Mechanical resilience and long-term retention have been improved through composite structures, interface engineering, and encapsulation strategies. There have been significant efforts to create lead-free substitutes in order to address environmental concerns regarding lead-based compounds. Even though compounds like Cs 3 Bi 2 I 9 , Cs 2 SnI 6 , and Cs 2 AgBiBr 6 are less toxic and more chemically stable, issues like oxidation, decreased mobility, and variability still exist. Strategies such as dimensional tuning and passivation are being explored to overcome these limitations. However, integration scalability, switching uniformity, and environmental stability remain key challenges for future research. Halide Perovskite-based ReRAM is positioned as a viable candidate for adaptable, ecologically friendly memory applications that meet the demands of modern electronics thanks to ongoing material innovation and system-level optimization.