| Téléchargement | - Voir la version finale : From soft harmonic phonons to fast relaxational dynamics in CH₃NH₃PbBr₃ (PDF, 1.5 Mio)
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| DOI | Trouver le DOI : https://doi.org/10.1103/PhysRevB.92.100303 |
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| Auteur | Rechercher : Swainson, I. P.1; Rechercher : Stock, C.; Rechercher : Parker, S. F.; Rechercher : Van eijck, L.; Rechercher : Russina, M.; Rechercher : Taylor, J. W. |
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| Affiliation du nom | - Conseil national de recherches du Canada. Technologies de sécurité et de rupture
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| Format | Texte, Article |
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| Résumé | The lead-halide perovskites, including CH₃NH₃PbBr₃, are components in cost effective, highly efficient photovoltaics, where the interactions of the molecular cations with the inorganic framework are suggested to influence the electronic and ferroelectric properties. CH₃NH₃PbBr₃ undergoes a series of structural transitions associated with orientational order of the CH₃NH₃ (methylammonium) molecular cation and tilting of the PbBr₃ host framework. We apply high-resolution neutron scattering to study the soft harmonic phonons associated with these transitions, and find a strong coupling between the PbBr₃ framework and the quasistatic CH₃NH₃ dynamics at low energy transfers. At higher energy transfers, we observe a PbBr₆ octahedra soft mode driving a transition at 150 K from bound molecular excitations at low temperatures to relatively fast relaxational excitations that extend up to ∼50–100 meV. We suggest that these temporally overdamped dynamics enables possible indirect band gap processes in these materials that are related to the enhanced photovoltaic properties. |
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| Date de publication | 2015-09-08 |
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| Maison d’édition | APS (American Physical Society) |
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| Dans | |
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| Langue | anglais |
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| Publications évaluées par des pairs | Oui |
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| Numéro NPARC | 23001091 |
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| Exporter la notice | Exporter en format RIS |
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| Signaler une correction | Signaler une correction (s'ouvre dans un nouvel onglet) |
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| Identificateur de l’enregistrement | 61d159a0-142f-4034-84f5-a57067be0b89 |
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| Enregistrement créé | 2016-12-12 |
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| Enregistrement modifié | 2020-06-02 |
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