A low-power filamentary memristor crossbar array enabled via cubic α-phase stabilized mixed-cation lead halide perovskites

Halide perovskite (HP)-based resistive switching memory has demonstrated significant advantages, particularly in terms of rapid switching speed and low power consumption. To address the thermal instability associated with CH₃NH₃⁺ ions, which have been mainly focused on in related fields, we developed resistive switching memory utilizing distorted HPs (FA_0.8Cs_0.2PbI₃), incorporating thermally stable A-site cations. Moreover, we improved nonvolatility by introducing SCN anions to stabilize the cubic α-phase. Unlike the pristine FACsPbI₃ (FCPI) device untreated by the SCN⁻-based additive, which features an α-phase/δ-phase heterostructure and exhibits unstable switching characteristics, the FCPI-SCN device demonstrates a stable cubic α-phase and extended retention behavior. After α-phase stabilization, trap-controlled emission becomes dominant in the FCPI-SCN device, confirming the stable filament formation through the HP layer. This strategic approach effectively suppresses the formation of heterostructures, reducing planar defects that serve as preferential sites for the multiple thin filament formation, thereby promoting stable filaments within the matrix. While pristine FCPI exhibits an unstable retention time of 40 s, FCPI-SCN demonstrates significantly improved performance including low operating voltages of 0.248 V/−0.116 V, a prolonged retention time of 11 000 s, and endurance over 1200 cycles. Additionally, we fabricated a 3 × 3 crossbar array with FCPI-SCN filamentary memristor devices. The crossbar array efficiently encodes and preserves letter-based bitmaps, thus showcasing its practical utility for reliable nonvolatile memory applications.