Synaptic plasticity and handwritten digits recognition of memristor based on high-stability lead-free Cs3Bi2Br9 perovskite thin film

Lead-free Cs3Bi2Br9 perovskite has emerged as a promising candidate for memristor and artificial synapse devices due to its high environmental stability and low toxicity compared to lead-based alternatives. In this work, we successfully prepared a high-quality Cs3Bi2Br9 perovskite film via simple spin-coating method combined with low-pressure assisted treatment. Based on the obtained Cs3Bi2Br9 film, a memristor with the structure of W/Cs3Bi2Br9/ITO was fabricated. The memristor demonstrated excellent resistive switching performance, including analog-switching behavior, high environmental stability (> 11 months), low operating voltages (VFORMING ~ 0.65 V, VSET ~ 0.53 ± 0.08 V, and VRESET ~ −0.83 ± 0.11 V), fast switching speed (< 1 μs), and long switching endurance (> 1100 cycles). Furthermore, the synaptic plasticity such as short-term plasticity, long-term plasticity, and synaptic weight potentiation and depression were successfully simulated by pulse-train measurement. Finally, a Fully Connected Neural Network built with the W/Cs3Bi2Br9/ITO memristor can obtain an accuracy of about 90% in recognizing handwritten digits. The results indicate that the lead-free Cs3Bi2Br9-based memristor has great potential for high-stability, cost-effective, eco-friendly, and low-power consumption nonvolatile memory and neuromorphic computing applications.