Effect of immersion time on morphology and resistive switching of CsPbBr₃ films via two-step spin-coating

The effect of immersion time on the morphology, crystallinity, and resistive switching of CsPbBr₃ thin films prepared via a two-step spin-coating method was systematically studied. Devices with an ITO/PEDOT:PSS/CsPbBr₃/Al structure were fabricated with immersion durations ranging from 5 to 20 min. SEM and XRD analyses indicated that longer immersion enhanced grain uniformity and crystallinity, whereas excessive duration led to the appearance of secondary phases. Electrical measurements demonstrated typical bipolar switching behavior, with the device prepared at 20 min achieving the highest ON/OFF ratio of approximately 1.6 × 10⁴, along with stable set and reset voltages of about ~ 0.6 V and ~  − 1.6 V, endurance over 300 cycles, and retention exceeding 10⁴ s. The devices fabricated under each immersion condition exhibited consistent switching characteristics, confirming the reproducibility of the observed performance trends. These findings underscore immersion time as a critical parameter for optimizing phase purity and performance in perovskite-based RRAM.