Disentangling Ion Migration from Artifacts in High-Fidelity ToF-SIMS Depth Profiling of Perovskite Solar Cells

Nico Fransaert^a, Jean V. Manca^a, Shabnam Ahadzadeh^f^,^g^,^h, Bart Ruttens^f^,^g, Jan D'Haen^f, Dirk Valkenborg^b, Bart Cleuren^c, Bart Vermang^d^,^f^,^g^,^h, Aslihan H. Babayigit^d^,^f^,^g^,^h

^aHasselt University, X-LAB, Agoralaan, 3590 Diepenbeek, Belgium

^bHasselt University, Data Science Institute, Interuniversity Institute for Biostatistics and Statistical Bioinformatics, Center for Statistics, Agoralaan, 3590 Diepenbeek, Belgium

^cHasselt University, Faculty of Sciences, Theory Lab, Agoralaan, 3590 Diepenbeek, Belgium

^dHasselt University, Faculty of Industrial Engineering Technology, Photovoltaic Technology Group, Wetenschapspark, 3590 Diepenbeek, Belgium

^eHasselt University, Faculty of Industrial Engineering Technology, Functional Materials Engineering Group, Wetenschapspark, 3590 Diepenbeek, Belgium

^fHasselt University, Institute for Materials Research (IMO-IMOMEC), Martelarenlaan 42, 3500 Hasselt, Belgium

^gIMEC, IMO-IMOMEC, Wetenschapspark 1, 3590 Diepenbeek, Belgium

^hEnergyVille, Thor Park 8320, 3600 Genk, Belgium

Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV26)

Uppsala, Sweden, 2026 May 18th - 20th

Organizers: Gerrit Boschloo, Ellen Moons, Feng Gao and Anders Hagfeldt

Oral, Aslihan H. Babayigit, presentation 065
Publication date: 11th March 2026

Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) is increasingly used in perovskite (PVK) solar cell research for its high chemical specificity and ability to probe buried interfaces without invasive sample preparation [1]. However, we show that acquisition and interpretation of ToF-SIMS data from multilayered PVK solar cells should not be conflated with that of its thin films [2,3]. Here, we present a rigorously substantiated ToF-SIMS methodology that separates true ion migration from artifact-induced signals, revealing widely underappreciated measurement artifacts. Through systematic comparison of thin films and full devices of archetypal MAPbI₃ (1.6 eV) and compositionally complex (FA₇₅Cs₂₅)(Pb₆₀Sn₄₀)I₃ (1.25 eV), we show that spurious ion gradients arise exclusively in multilayer stacks, driven by top-layer interactions. We confirm their measurement-induced origin using a controlled peeling protocol designed to isolate these effects. We further introduce a novel fluence-matched acquisition protocol and the first statistically grounded workflow for replicate-based analysis—demonstrating that single-profile measurements can lead to contradictory interpretations, particularly in studies targeting subtle interfacial phenomena by trace passivation. Applying this framework, we enable reliable detection and aging analysis of buried self-assembled monolayers (SAMs), whose ultrathin (~1 nm), localized nature presents unique analytical challenges and growing importance in the design of molecular selective layers for high-efficiency, stable devices. Together, these findings establish a reproducible, artifact-aware framework for high-fidelity ToF-SIMS depth profiling in PVK solar cells and provide a reference standard for reliable chemical analysis of hybrid multilayer semiconductors. This work advances best practices in nanoscale characterization and in doing so supports precision interface engineering across next-generation energy technologies and beyond.

Keywords: Perovskite solar cells; ToF-SIMS; Depth profiling; Interface characterization, Ion migration; Self-assembled monolayers; Measurement artifacts; Energy materials.

References:

[1] Web of Science, research paper publication statistics, keywords: ‘ToF-SIMS’ and ‘perovskites’, year: 2019-2024, retrieved on 20th January 2025.

[2] Noël, C., Pescetelli, S., Agresti, A., Franquet, A., Spampinato, V., Felten, A., di Carlo, A., Houssiau, L. and Busby, Y. (2019). Hybrid perovskites depth profiling with variable-size argon clusters and monatomic ions beams. Materials, 12(5), 726.

[3] Harvey, S. P., Zhang, F., Palmstrom, A., Luther, J. M., Zhu, K. and Berry, J. J. (2019). Mitigating measurement artifacts in TOF-SIMS analysis of perovskite solar cells. ACS applied materials & interfaces, 11(34), 30911-30918.

Acknowledgements:

N.F. and J.V.M. thank dr. Alexis Franquet for overseeing the maintenance of the ToF-SIMS equipment at IMEC (Leuven, Belgium), which facilitated our measurements through the HERCULES ToF-SIMS collaboration 2022-2025 (IMEC/UHasselt). N.F. and A.H.B. thank Gabriel Belchior Miranda for insightful discussions. This research was carried out under financial support by the Research Foundation Flanders (FWO) under mandate grant IDs 11K4324N, 1260022N, 1SA4523N and 1297525N, and financial support by BOF-UHasselt grant ID R-12384.

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