Charting the thermodynamic stability of hybrid perovskite alloys with machine learning

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Hauptverfasser: Laakso, Jarno, Tiihonen, Armi, Rinke, Patrick
Format: Preprint
Veröffentlicht: 2026
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author Laakso, Jarno
Tiihonen, Armi
Rinke, Patrick
author_facet Laakso, Jarno
Tiihonen, Armi
Rinke, Patrick
contents Alloy-based perovskite solar cells offer tunable properties and improved stability, but their complexity has impeded accurate modeling, hindering development. We present a machine-learning (ML) accelerated atomistic modeling approach for the phase stability of (Cs/FA)Pb(Br/I)3 and (Cs/FA)Sn(Br/I)3 perovskites, with FA being formamidinium. To make such quaternary alloys tractable, we adopt a two-level ML strategy, combining 1) graph neural network interatomic potentials trained on density functional theory data for efficient structure relaxations with 2) secondary ML models for direct energy prediction from unrelaxed structures. These models enable computations of free energy landscapes across compositions and phases, capturing alloy disorder and FA molecular orientations. Our results reveal narrower stable composition regions for the Sn-based system compared to its Pb-based counterpart, limiting options for compositional engineering. Maximum stability occurs at high I content, and no stabilization is observed near the center of the composition space. Our results guide the design of stable perovskites.
format Preprint
id arxiv_https___arxiv_org_abs_2605_30012
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Charting the thermodynamic stability of hybrid perovskite alloys with machine learning
Laakso, Jarno
Tiihonen, Armi
Rinke, Patrick
Materials Science
Alloy-based perovskite solar cells offer tunable properties and improved stability, but their complexity has impeded accurate modeling, hindering development. We present a machine-learning (ML) accelerated atomistic modeling approach for the phase stability of (Cs/FA)Pb(Br/I)3 and (Cs/FA)Sn(Br/I)3 perovskites, with FA being formamidinium. To make such quaternary alloys tractable, we adopt a two-level ML strategy, combining 1) graph neural network interatomic potentials trained on density functional theory data for efficient structure relaxations with 2) secondary ML models for direct energy prediction from unrelaxed structures. These models enable computations of free energy landscapes across compositions and phases, capturing alloy disorder and FA molecular orientations. Our results reveal narrower stable composition regions for the Sn-based system compared to its Pb-based counterpart, limiting options for compositional engineering. Maximum stability occurs at high I content, and no stabilization is observed near the center of the composition space. Our results guide the design of stable perovskites.
title Charting the thermodynamic stability of hybrid perovskite alloys with machine learning
topic Materials Science
url https://arxiv.org/abs/2605.30012