Lead-Free Cs₃BiBr₆ Perovskite Memristor for Biomimetic Nociceptor Emulation and Information Encryption

Driven by the demand for device multifunctionality in fields such as neuromorphic computing, biomimetic sensing, and information security, memristors have become a research focus due to their dual capabilities of data storage and signal processing. Herein, a Cs₃BiBr₆ lead-free perovskite memristor with a sandwich structure of Ag/PMMA/Cs₃BiBr₆/ITO is fabricated and systematically investigated. Under a low current compliance of 1 mA, the device demonstrates stable bipolar resistive switching behavior, including over 800 switching cycles, an average on/off ratio greater than 20, and good data retention. At 10 mA, random high-resistance state distribution enables construction of a true random number array. The switching mechanism is dominated by Ag atoms and bromide vacancies driving conductive filaments fracture-regeneration. Moreover, the device emulates the nociceptor function in biological systems, achieving graded stimulus discrimination and postinjury hyperalgesia reproduction. Additionally, OR/AND/XOR logic gates are constructed via bipolar resistive switching, with digital information and image encryption/decryption realized via the integration of the random key matrix.