Electrochemical Doping of Halide Perovskites with Silver Interstitial Ions: Mechanistic Insights and Enhanced Performance in Memristor Applications

Halide perovskites have garnered significant attention for their exceptional carrier mobility, balanced bipolar transport properties, and ion-electron mixing conductivity, making them highly promising for applications, such as solar cells, photodetectors, and memristors. Despite their potential, intrinsic ions and defects within these materials complicate effective doping, and interactions between metal electrodes and perovskite materials can trigger interfacial chemical reactions that compromise device stability and performance. This study examines the influence of Ag electrodes on perovskite devices, specifically investigating the n-doping effects of Ag_i⁺ interstitial ions in MAPbI₃ perovskites through an integrated approach combining first-principles density functional theory (DFT) calculations and experimental analysis. Findings reveal that Ag_i⁺ interstitial ions, generated electrochemically at Ag electrodes, penetrate the MAPbI₃ structure and migrate under an applied electric field, achieving stable n-doping under controlled bias conditions. Detailed characterization of the doping process was conducted using current density-time (<i>J</i>-<i>t</i>) measurements, electrochemical AC impedance (EIS), TOF-SIMS/XPS depth profiling, and temperature/illumination-dependent studies. Additionally, the memristive behavior of the device, including doping mechanisms and the formation of metallic conductive filaments, was demonstrated, offering insights into its potential applications in advanced electronics. These findings elucidate the physicochemical interactions at metal-perovskite interfaces under bias in diode devices.