Single Best Fits Can Be Misleading: Resolving Common Trapping Signatures across FA--Cs Perovskites
Abstract
Identifying defects responsible for non-radiative recombination in metal-halide perovskites remains challenging, with no common defect signatures established across compositions. Here, we combine fluence-dependent time-resolved photoluminescence, full Shockley--Read--Hall modelling and Bayesian posterior inference across an FA1−xCsxPbI3 compositional series. We show that trap occupation governs carrier dynamics and defect-parameter identifiability in semiconducting materials: weakly occupied states exhibit electron-capture-coefficient--trap-density degeneracies, whereas trap filling lifts them. In our perovskite systems, a non-degenerate signature Tβ, characterized by a strongly asymmetric βp/βn capture-coefficient ratio, occurs across all compositions, suggesting substantial trap filling is a general feature of perovskite carrier dynamics. We further identify Tα as a shared, device-performance-limiting non-radiative recombination channel, while a shallow Tε signature unique to FAPbI3 produces the largest steady-state non-radiative recombination rate and is consistent with the previously observed high stacking-fault density of this composition. This framework therefore provides a basis for comparing trapping signatures across different semiconducting materials at room temperature.
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BibTeX
@misc{simmonds2026single,
title = {{Single Best Fits Can Be Misleading: Resolving Common Trapping Signatures across FA--Cs Perovskites}},
author = {Maxim Simmonds and Katarzyna Pydzińska-Białek and Thomas C. Rossi and Mostafa Othman and Aïcha Hessler-Wyser and Christian Wolff and Christophe Ballif and Vincent M. Le Corre and Eva Unger},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.21545},
eprint = {2609.21545},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.21545},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Single Best Fits Can Be Misleading: Resolving Common Trapping Signatures across FA--Cs Perovskites
AU - Maxim Simmonds
AU - Katarzyna Pydzińska-Białek
AU - Thomas C. Rossi
AU - Mostafa Othman
AU - Aïcha Hessler-Wyser
AU - Christian Wolff
AU - Christophe Ballif
AU - Vincent M. Le Corre
AU - Eva Unger
PY - 2026
DA - 2026/09/18
PB - arXiv
DO - 10.48550/arxiv.2609.21545
UR - https://arxiv.org/abs/2609.21545
AB - Identifying defects responsible for non-radiative recombination in metal-halide perovskites remains challenging, with no common defect signatures established across compositions. Here, we combine fluence-dependent time-resolved photoluminescence, full Shockley--Read--Hall modelling and Bayesian posterior inference across an FA_1−xCs_xPbI_3 compositional series. We show that trap occupation governs carrier dynamics and defect-parameter identifiability in semiconducting materials: weakly occupied states exhibit electron-capture-coefficient--trap-density degeneracies, whereas trap filling lifts them. In our perovskite systems, a non-degenerate signature Tβ, characterized by a strongly asymmetric β_p/β_n capture-coefficient ratio, occurs across all compositions, suggesting substantial trap filling is a general feature of perovskite carrier dynamics. We further identify Tα as a shared, device-performance-limiting non-radiative recombination channel, while a shallow Tε signature unique to FAPbI_3 produces the largest steady-state non-radiative recombination rate and is consistent with the previously observed high stacking-fault density of this composition. This framework therefore provides a basis for comparing trapping signatures across different semiconducting materials at room temperature.
ER -