Controllable volatile-to-nonvolatile memristive switching in single-crystal lead-free double perovskite with ultralow switching electric field

All-inorganic lead-free double perovskite offers a potential material platform for electronic or optoelectronic memory devices owing to its ionic migration-based electrical transport, high photosensitivity, low toxicity, and environmental stability. However, the commonly used polycrystalline perovskite films severely restrict device performance. Herein, we demonstrate a high-performance memristor based on single-crystal double perovskite Cs 2 AgBiBr 6 with an ultralow switching electric field of 6.67 × 10 4 V m −1 and a high current on/off ratio of 10 7 . Remarkably, the resistive switching of Cs 2 AgBiBr 6 is found to be thickness-dependent, which evolves from volatile threshold to nonvolatile resistance switching with the crystal thickness from 100 to 800 nm. Elemental analysis reveals that the formation of conductive channels in Cs 2 AgBiBr 6 is associated with the migration of Br vacancies with low activation energy. In addition, the formed conductive channels can be annihilated by light illumination with controlled wavelength and intensity, which leads to the realization of optoelectronic memories with separate electrical-writing and optical-erasing processes. Our findings provide deep insights into the ionic migration in single-crystal perovskite and pave the way for its future application in electronic and optoelectronic memory devices.