Air-Stable, Eco-Friendly RRAMs Based on Lead-Free Cs₃Bi₂Br₉ Perovskite Quantum Dots for High-Performance Information Storage

Development of lead-free halide perovskites that are innocuous and stable has become an attractive trend in resistive random access memory (RRAM) fields. However, their inferior memory properties compared with the leadbased analogs hinder their commercialization. Herein, the lead-free Cs₃Bi₂Br₉ perovskite quantum dot (PQD)-based RRAMs are reported with outstanding memory performance, where Cs₃Bi₂Br₉ quantum dots (QDs) are synthesized via a modified ligand-assisted recrystallization process. This is the first report of applying Cs₃Bi₂Br₉ QDs as the switching layer for RRAM device. The Cs₃Bi₂Br₉ QD device demonstrates nonvolatile resistive switching (RS) effect with large ON/OFF ratio of 10⁵, low set voltage of −0.45 V, as well as good reliability, reproducibility, and flexibility. Concurrently, the device exhibits the notable tolerance toward moisture, heat and light illumination, and longterm stability of 200 days. More impressively, the device shows the reliable light-modulated RS behavior, and therefrom the logic gate operations including “AND” and “OR” are implemented, foreboding its prospect in logic circuits integrated with storage and computation. Such multifunctionality of device could be derived from the unique 2D layered crystal structure, small particle size, quantum confinement effect, and photoresponse of Cs₃Bi₂Br₉ QDs. This work provides the strategy toward the high-performance RRAMs based on stable and eco-friendly perovskites for future applications.