Impact of Hydroiodic Acid on Resistive Switching Performance of Lead-Free Cs₃Cu₂I₅ Perovskite Memory

Abstract

Herein, we employed lead-free Cs₃Cu₂I₅ perovskite films as the functional layers to construct Al/Cs₃Cu₂I₅/ITO memory devices and systematically investigated the impact on the corresponding resistive switching (RS) performance via adding different amounts of hydroiodic acid (HI) in Cs₃Cu₂I₅ precursor solution. The results demonstrated that the crystallinity and morphology of the Cs₃Cu₂I₅ films can be improved and the resistive switching performance can be modulated by adding an appropriate amount of HI. The obtained Cs₃Cu₂I₅ films by adding 5 μL HI exhibit the fewest lattice defects and flattest surface (RMS = 13.3 nm). Besides, the memory device, utilizing the optimized films, has a low electroforming voltage (1.44 V), a large on/off ratio (∼65), and a long retention time (10⁴ s). The RS performance impacted by adding HI, providing a scientific strategy for improving the RS performance of iodine halide perovskite-based memories.