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Ferreira AC, Létoublon A, Paofai S, Raymond S, Ecolivet C, Rufflé B, Cordier S, Katan C, Saidaminov MI, Zhumekenov AA, Bakr OM, Even J, Bourges P. Elastic Softness of Hybrid Lead Halide Perovskites. Phys Rev Lett 2018; 121:085502. [PMID: 30192590 DOI: 10.1103/physrevlett.121.085502] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Indexed: 05/17/2023]
Abstract
Much recent attention has been devoted towards unraveling the microscopic optoelectronic properties of hybrid organic-inorganic perovskites. Here we investigate by coherent inelastic neutron scattering spectroscopy and Brillouin light scattering, low frequency acoustic phonons in four different hybrid perovskite single crystals: MAPbBr_{3}, FAPbBr_{3}, MAPbI_{3}, and α-FAPbI_{3} (MA: methylammonium, FA: formamidinium). We report a complete set of elastic constants characterized by a very soft shear modulus C_{44}. Further, a tendency towards an incipient ferroelastic transition is observed in FAPbBr_{3}. We observe a systematic lower sound group velocity in the technologically important iodide-based compounds compared to the bromide-based ones. The findings suggest that low thermal conductivity and hot phonon bottleneck phenomena are expected to be enhanced by low elastic stiffness, particularly in the case of the ultrasoft α-FAPbI_{3}.
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Affiliation(s)
- A C Ferreira
- Laboratoire Léon Brillouin, CEA-CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette, France
- Univ Rennes, INSA Rennes, CNRS, Institut FOTON - UMR 6082, F-35000, Rennes, France
| | - A Létoublon
- Univ Rennes, INSA Rennes, CNRS, Institut FOTON - UMR 6082, F-35000, Rennes, France
| | - S Paofai
- Univ Rennes, ENSCR, INSA Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, F-35000, Rennes, France
| | - S Raymond
- Univ. Grenoble Alpes, CEA, INAC, MEM, 38000 Grenoble, France
| | - C Ecolivet
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - B Rufflé
- Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, Montpellier, FR-34095, France
| | - S Cordier
- Univ Rennes, ENSCR, INSA Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, F-35000, Rennes, France
| | - C Katan
- Univ Rennes, ENSCR, INSA Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, F-35000, Rennes, France
| | - M I Saidaminov
- King Abdullah University of Science and Technology (KAUST), KAUST Catalysis Center, KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Thuwal 23955-6900, Saudi Arabia
| | - A A Zhumekenov
- King Abdullah University of Science and Technology (KAUST), KAUST Catalysis Center, KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Thuwal 23955-6900, Saudi Arabia
| | - O M Bakr
- King Abdullah University of Science and Technology (KAUST), KAUST Catalysis Center, KAUST Solar Center, Physical Sciences and Engineering Division (PSE), Thuwal 23955-6900, Saudi Arabia
| | - J Even
- Univ Rennes, INSA Rennes, CNRS, Institut FOTON - UMR 6082, F-35000, Rennes, France
| | - P Bourges
- Laboratoire Léon Brillouin, CEA-CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette, France
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