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Determine kinetic stability of metastable halide perovskites via accurate crystallization free-energy barriers

Determine the actual kinetic stability of metastable halide perovskites, including the black perovskite polymorphs of cesium lead iodide (CsPbI3), by accurately calculating free energy barriers for the multi-step solid–solid crystallization processes and using these barriers to compute the corresponding phase transition rates.

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Background

The paper investigates atomistic mechanisms of solid–solid phase transitions in CsPbI3 using multi-scale simulations, revealing complex multi-step pathways with stacked-faulted intermediates and facet-dependent growth behavior. Building on these insights, the authors emphasize that quantifying free energy barriers of the multi-step crystallization process is essential to compute phase transition rates.

They explicitly highlight that determining the kinetic stability of metastable perovskites (such as black-phase CsPbI3 relative to the thermodynamically stable δ-phase) remains unresolved because accurate barrier calculations across the full crystallization pathway are still lacking. This quantification is needed to assess kinetic stability and predict transformation dynamics under processing conditions.

References

Accurate calculations of free energy barriers for the multi-step crystallization process will serve as a crucial parameter for calculating the rates of phase transitions to determine the actual kinetic stability of these meta-stable perovskites: one of the key unsolved problem for halide perovskites.

— Size dependent solid-solid crystallization of halide perovskites (2404.05644 - Ahlawat, 8 Apr 2024) in Discussion and Conclusion (Section: Discussion and Conclusion)