In light of recent improvements of perovskite solar cell (PSC) stability, evaluation of life expectancy can become costly as T80 could surpass 1000s of hours. ^[1] Accelerated testing could offer a solution by reducing resources needed to advance in preventing the initial stages of degradation, especially if properly related to long-term studies and by use of semi-automated analysis. Additionally, by suitable experiments, it becomes feasible to track physical phenomena occurring during the application of stress, and consequences for stability of reversible processes such as ion migration. ^[2] We have developed in-situ characterization methods to be applied in line with or parallel to ISOS-grade indoor and outdoor operational testing. These include X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS) and photoluminescence. I aim to present implementations of accelerated stress tests on PSCs under operando conditions, among others applying continuous light irradiation and bias-voltage. We followed device response with time under bias via in-situ XRD analyses in conjunction with quasi in-situ EIS. Our results demonstrate a clear relation between halide perovskite lattice expansion/constriction, increased ionic motion, current decay with time and device stability. ^[3] EIS analyses revealed a threshold where some of these bias-induced degradation mechanisms become irreversible. By a combination of detailed characterization, we could elucidate mechanisms of actuation when using additive engineering to passivate shallow defects. ^[3-5]

[1] J. Sou, B. Yang, E. Mosconi et al., Nat Energy2024, 9, 172-183.
[2] F. Baumann, S.R. Raga, M. Lira-Cantú, APL Energy2023, 1, 011501.
[3] F. Baumann et al. ACS Energy Letters 2025 10 (1), 476-483.
[4] H. Xie et al., Joule2021, 5, 1246-1266.
[5] M. Karimipour et al., Adv. Energy Mater.2023, 13, 2301959.