Air-Stable Lead-Free Perovskite Thin Film Based on CsBi₃I₁₀ and Its Application in Resistive Switching Devices

The development of organic-inorganic hybrid perovskite materials has been rapid in recent years; but their applications are limited by the toxicity and stability of the materials. To address these issues in the context of resistive switching devices, an inorganic lead-free perovskite namely CsBi₃I₁₀ is developed. Uniform and pinhole-free CsBi₃I₁₀ thin films can be fabricated by using CsI-rich precursor solution via a facile antisolvent-assisted spin-coating method. The nonvolatile resistive switching devices based on CsBi₃I₁₀ demonstrate a large on/off ratio (10³), reliable retention properties (10⁴ s), and endurance (150 cycles). Conductive atomic force microscopy reveals that the high- and low-resistance states are formed by breaking and formation of conductive filaments in the perovskite thin film. Because of the excellent stability of the CsBi₃I₁₀ perovskite, the devices exhibit no obvious change in resistive switching behavior even after over 2 month storage in an ambient (60% relative humidity) environment. Our work suggests that the all-inorganic lead-free CsBi₃I₁₀ perovskite has great potential in resistive switching memory as well as in other optoelectronic devices where toxicity and stability are a concern.