Self‐Assembly of Delta‐Formamidinium Lead Iodide Nanoparticles to Nanorods: Study of Memristor Properties and Resistive Switching Mechanism

Abstract In the quest for advanced memristor technologies, this study introduces the synthesis of delta‐formamidinium lead iodide ( δ ‐FAPbI ₃ ) nanoparticles (NPs) and their self‐assembly into nanorods (NRs). The formation of these NRs is facilitated by iodide vacancies, promoting the fusion of individual NPs at higher concentrations. Notably, these NRs exhibit robust stability under ambient conditions, a distinctive advantage attributed to the presence of capping ligands and a crystal lattice structured around face‐sharing octahedra. When employed as the active layer in resistive random‐access memory devices, these NRs demonstrate exceptional bipolar switching properties. A remarkable on/off ratio (10 ⁵ ) is achieved, surpassing the performances of previously reported low‐dimensional perovskite derivatives and α ‐FAPbI ₃ NP‐based devices. This enhanced performance is attributed to the low off‐state current owing to the reduced number of halide vacancies, intrinsic low dimensionality, and the parallel alignment of NRs on the FTO substrate. This study not only provides significant insights into the development of superior materials for memristor applications but also opens new avenues for exploring low‐dimensional perovskite derivatives in advanced electronic devices.