Impact of Composition and Temperature on Ionic Degradation and Recovery in Perovskite Solar Cells

Paria Forozi Sowmeeh^a, Jarla Thiesbrummel^a, Andres Felipe Castro Mendez^a, Sahil Shah^b, Biruk Alebachew Seid^a, Francisco Peña-Camargo^c, Thomas Hultzsch^a, Jan Hagenberg^a, Martin Stolterfoht^d, Felix Lang^a

^aInstitute of Physics and Astronomy, University of Potsdam, Potsdam-Golm, Germany

^bUniversity of Queensland, Australia

^cHelmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany

^dElectronic Engineering Department, The Chinese University of Hong Kong, Hong Kong SAR, China

Proceedings of MATSUS Fall 2026 Conference (MATSUSFall26)

B2 Ionic Dynamics and Transport Phenomena in Metal Halide Perovskites

Palma, Spain, 2026 October 26th - 30th

Organizers: Silvia Colella, Sofia Masi and Pablo P. Boix

Oral, Paria Forozi Sowmeeh, presentation 205
Publication date: 22nd July 2026

Mobile ions in metal halide perovskites are known to negatively impact the intrinsic stability of perovskite-based solar cells (PSCs). Under illumination, mobile ions can migrate along grain boundaries and accumulate at perovskite interfaces, where they create metastable trap states, and in some cases, penetrate into charge transport layers, ultimately contributing to device failure ^1,2.

In this presentation, we quantitatively investigate photo-induced aging and self-healing in PSCs under light/dark cycling. Under prolonged illumination, the device degrades as ion density and ionic loss increase.³ However, when the device is allowed to rest in the dark⁴, part of this ionic loss is recovered, leading to reduced ion density and partial performance restoration. The incomplete restoration of power conversion efficiency (PCE) indicates the simultaneous presence of reversible and irreversible degradation mechanisms, which progressively accumulate over successive cycles. Consequently, degradation accumulates over repeated light/dark cycles, representing a key factor that limits the operational stability of PSCs.

By directly comparing a stable and a poorly stable system, we observe that, while degradation and subsequent recovery are clearly observable in the poorly stable device, the stable device exhibits gradual performance improvement during successive cycles. This contrasting behavior highlights the different metastability characteristics of the two device types. Moreover, we investigate the link between PSC recovery and temperature. We further identify perovskite composition as a key factor governing device self-healing during dark resting. Complementary current density-voltage (J-V), fast hysteresis (FH), and bias-assisted charge extraction (BACE) analyses confirm these findings.

While degradation is generally considered unavoidable in PSCs, understanding the intrinsic self-repair capability of perovskites and learning how to control it to slow the efficiency loss process offers a promising step towards achieving stable perovskite solar cells. Together, these findings highlight light/dark cycling-based test protocols as a transformative approach for understanding and controlling degradation, offering new pathways toward extending the lifetime of PSCs.

References:

[1] Azpiroz, J. M., Mosconi, E., Bisquert, J. & De Angelis, F. Defect migration in methylammonium lead iodide and its role in perovskite solar cell operation. Energy Environ. Sci. 8, 2118–2127 (2015).

[2] Thiesbrummel, J. et al. Ion migration in perovskite solar cells. Nature Reviews Chemistry Preprint at https://doi.org/10.1038/s41570-025-00790-8 (2026).

[3] Thiesbrummel, J. et al. Ion-induced field screening as a dominant factor in perovskite solar cell operational stability. Nat. Energy 9, 664–676 (2024).

[4] Domanski, K. et al. Migration of cations induces reversible performance losses over day/night cycling in perovskite solar cells. Energy Environ. Sci. 10, 604–613 (2017).

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