Interfacial engineering can significantly reduce hysteresis in perovskite solar cells (PSCs) but does not completely eliminate it. Research indicates that the hysteresis phenomenon primarily arises from the formation and release of interfacial charges at the electrode/perovskite interfaces, rather than solely from mobile ion migration within the perovskite layer itself. For example, a study using Kelvin probe force microscopy showed that localized interfacial charges at the anode interface screened the cell’s electric field, causing hysteresis; these charges formed and dissipated over milliseconds, which dominated the hysteresis behavior beyond the contribution of mobile ions.
Accurate interface engineering, such as the introduction of passivation layers or modifying the interfaces to suppress ion migration, can greatly reduce hysteresis effects and improve device stability. For example, using a NdCl3 interfacial layer at the rear electrode notably suppressed iodide ion migration, reduced trap densities, and achieved power conversion efficiencies up to 22.16% with negligible hysteresis. Similarly, modifying the hole transport layer or using 2D/3D passivation strategies improves energy band alignment and reduces interfacial recombination, which also helps mitigate hysteresis and improves stability.
However, despite these advances, hysteresis is not completely eliminated because the fundamental dynamic processes of charge accumulation, ion migration, and interfacial charge trapping/release can only be mitigated to a certain extent by engineering. Some studies demonstrate nearly negligible hysteresis but not absolute elimination under all operating conditions. Thus, interfacial engineering is a critical and effective approach to minimize hysteresis but cannot fully eradicate it due to the intrinsic material and device physics involved.
Summary:
| Aspect | Effect of Interfacial Engineering |
|---|---|
| Hysteresis Reduction | Significant reduction by suppressing ion migration and charge traps |
| Mechanism of Hysteresis | Mainly interfacial charge formation and release, minor ionic field effects |
| Device Stability | Improved by interface modification and passivation layers |
| Complete Elimination | Not fully achievable due to intrinsic dynamic processes |
In conclusion, interfacial engineering substantially minimizes hysteresis in perovskite solar cells but does not completely eliminate it across all device configurations and operating conditions.
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