Polyethylene-Glycol-Modified Halide Perovskite for Enhancing the Switching Ratio and Cycling Stability of Resistive Random Access Memory

As a result of the apparent hysteresis caused by ion migration, halide perovskites (HPs) are used as the active layer of resistive devices. Here, polyethylene glycol (PEG) is used to form an organic network in the Cs₃Bi₂Br₉ precursor solution to influence the nucleation growth rate of the substrate and, thus, control the perovskite surface morphology, crystallization process, and halide ion migration activation energy. Furthermore, the organic network consisting of non-conducting polymer PEG rests on the boundaries between perovskite crystals to cross-link perovskite particles. As a result, the particle size of perovskite increased from 64.6 to 76.2 nm as the nucleation rate of perovskite gradually decreased with the increase of the PEG concentration and the activation energy of the ion increases from 0.15 to 0.25 eV. Meanwhile, as the concentration of PEG increases, the switching ratio and cycle stability of the devices is improved.