ION MIGRATION MODEL IN PEROVSKITE SOLAR CELLS

Ion migration in perovskite solar cells critically influences device performance, stability, and hysteresis behavior. This study presents a comprehensive model describing ionic transport mechanisms within hybrid organic–inorganic perovskite structures, focusing on vacancy-assisted migration of halide ions and mobile cations under internal electric fields. The model integrates drift–diffusion equations with electrostatic coupling to account for time-dependent ion redistribution and its impact on charge carrier dynamics. Particular attention is given to the interaction between ionic defects and electronic processes, including recombination and band bending at interfaces. Numerical simulations reveal that ion accumulation at selective contacts leads to transient photovoltaic responses and long-term degradation pathways. The proposed framework provides insights into mitigating hysteresis and enhancing operational stability through material engineering and interface optimization. These findings contribute to the fundamental understanding of ion–electron coupling and offer practical strategies for improving the efficiency and durability of next-generation perovskite photovoltaic devices.