An air-stable artificial synapse based on a lead-free double perovskite Cs2AgBiBr6 film for neuromorphic computing

Halide perovskites (HPs) are promising materials for preparing nonvolatile memory and artificial synapse devices. However, the instability and toxicity of lead HPs seriously restrict their further application. Herein, a lead-free and air-stable Ag/polymethylmethacrylate (PMMA)/Cs2AgBiBr6/ITO device is fabricated, which exhibits typical resistive switching (RS) characteristics and synaptic behaviors, including long-term potentiation (LTP), long-term depression (LTD), paired-pulse facilitation (PPF) and spike-dependent plasticity. The ion migration of Br− and Ag+ in Cs2AgBiBr6 led to the formation and fracture of a conductive filament. Notably, no obvious decay in the device performance was observed after being directly exposed to the ambient environment for 20 days, indicating that the device exhibits good environmental stability. Furthermore, the recognition rate reaches 91.3% by using the MNIST handwritten data set. This air-stable and lead-free device provides a new candidate for the next generation of neuromorphic computation based on halide perovskites.