Role of annealing conditions on the resistive switching behavior of solution processed formamidinium lead bromide FaPbBr3 devices

Hybrid organic-inorganic halide perovskites (OIHPs) are emerging as strong contenders for next-generation flexible nonvolatile memory systems due to their fascinating properties, including mixed ionic-electronic transport, high abundance, and cost-effective fabrication processes. This study investigates the impact of annealing the active layer on the resistive switching (RS) performance of FTO/formamidinium lead bromide (FAPbBr₃)/Al devices. Devices were fabricated with the FAPbBr₃ layer annealed under different conditions: 50 °C for 10 min (Device D1), 60 °C for 20 min (Device D2), and 100 °C for 30 min (Device D3). Each device displayed distinct bipolar hysteresis in current-voltage (I-V) characteristics, with Device D2 displaying the most prominent hysteresis loop. X-ray diffraction (XRD) analysis identified that the FAPbBr₃ layer in Device D2 predominantly contained the FABr–PbBr₂–DMF intermediate complex, resulting in a higher density of native defects. This increased defect density likely enhanced bromide ion migration, facilitating greater ionic accumulation at the interface, which contributed to the pronounced hysteresis loop. A model combining ionic transport and energy band modulation is proposed to elucidate the resistive switching (RS) mechanism in these devices. Capacitance-frequency (C–f) analysis further corroborated the highest interfacial charge accumulation for Device D2, reflected by its maximum accumulation capacitance. Additionally, the Device D2 exhibited the highest ionic conductivity, driving enhanced ion migration and accumulation at the interface, thereby enhancing the RS behavior. This work highlights the critical role of annealing in optimizing the RS performance, offering valuable insights for advancing perovskite-based RS device technologies.