Lead-Free FA3BiI6 Perovskite Memristor for Logic Gate Circuits and Data Encryption

The heavy metal toxicity of lead-based halide perovskites hinders their practical application in memristors. Herein, we report a lead-free FA₃BiI₆-based sandwich-structured memristor. The device exhibits stable bipolar resistive switching with negligible degradation over 200 DC cycles and a retention time of 3000 s, and excellent uniformity in switching voltages and resistance states. Mechanistic analysis reveals that electric-field-driven Ag⁺ migration, inducing local conductive filaments, is the key to the resistive-switching behavior. Pulse tests demonstrate that the device can mimic various biological synaptic plasticity, including excitatory postsynaptic current (EPSC), paired-pulse facilitation (PPF), and long-term potentiation/depression (LTP/LTD). Furthermore, OR, AND, and XOR basic logic gate circuits are constructed, with XOR operations being employed for lossless symmetric encryption/decryption of RGB color images, and the original image features being completely masked. This work provides a new approach for the development of environmentally friendly halide perovskite-based hardware encryption devices.