Impact of Iodide Ion Migration on Perovskite Solar Cells
- Operational Instability and Degradation: Iodide ions (I− and I3−) tend to migrate within the perovskite structure, leading to phase segregation and degradation of the perovskite films under illumination or operational conditions. This migration contributes to the instability and diminished performance of perovskite solar cells over time.
- Hysteresis in Solar Cells: The migration of iodide ions causes modulation of interfacial barriers, resulting in current-voltage hysteresis. This hysteresis is a characteristic phenomenon in perovskite solar cells that affects their efficiency and performance. Hysteresis complicates the measurement and prediction of cell performance, contributing to operational instability.
- Photocurrent Hysteresis and Device Efficiency: Ion migration, including iodide ions, is linked to the observed photocurrent hysteresis and other unusual phenomena in perovskite solar cells, such as switchable photovoltaic effects and electric-field-driven reversible phase transitions. This hysteresis can significantly reduce device efficiency and stability.
- Thermal Stability and Mitigation Strategies: To improve thermal stability, strategies have been developed to inhibit iodide ion migration. For example, additives like polyetheramine (PEA) can form strong interactions with iodides, effectively locking them in place and preventing migration. This approach can enhance thermal stability and device performance by reducing iodide loss and defects associated with ion migration.
- Future Directions: Despite advancements, thorough understanding and mitigation of ion migration remain crucial for enhancing the thermal stability and overall performance of perovskite solar cells. Addressing these challenges is essential for the long-term viability of these devices in practical applications.
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