Anharmonic Lattice Dynamics in CsPbBr3

ORAL

Abstract

CsPbBr3 is a promising material for use in solar cells and thermoelectrics. The suitability of halide perovskites as photovoltaics derives from the long lifetimes of photoexcited carriers before recombination and it has been theorized that this is due to local polar fluctuations. Furthermore, CsPbBr3 has been shown to exhibit ultralow thermal conductivity which makes it attractive for use in thermoelectrics. CsPbBr3 has several lattice instabilities undergoing a cubic to tetragonal transition at ~400K before transforming to an orthorhombic phase at ~360K.

We report inelastic neutron scattering (INS) studies, supported by anharmonic first-principles simulations, on CsPbBr3 across its three phases. These momentum-resolved measurements allow us to investigate phonon behavior across the Brillouin zone and hence phonon-phonon scattering rates which directly impact thermal conductivity. We find large overall broadening of phonons, even at low temperature, but also a large temperature-dependent anisotropy in the anharmonicity.

*U.S. Department of Energy, Oce of Science, Basic Energy Sciences, Materials Sciences and Engineering Division, under Award No. DE-SC0019299.

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Presenters

  • Tyson Lanigan-Atkins

    • Duke University
    • Mechanical Engineering and Materials Science, Duke University

Authors

  • Tyson Lanigan-Atkins

    • Duke University
    • Mechanical Engineering and Materials Science, Duke University

  • Xing He

    • Duke University

  • Matthew Krogstad

    • Argonne National Laboratory
    • Argonne National Lab
    • Material Science Division, Argonne National Laboratory
    • Materials Science Division, Argonne National Lab
    • Materials Science Division, Argonne National Laboratory
    • Material Science, Argonne National Laboratory

  • Raymond Osborn

    • Argonne National Laboratory
    • Argonne National Lab
    • Material Science Division, Argonne National Laboratory
    • Materials Science Division, Argonne National Lab
    • Materials Science Division, Argonne National Laboratory
    • Material Science, Argonne National Laboratory

  • Stephan Rosenkranz

    • Materials Science Division, Argonne National Lab
    • Argonne National Laboratory
    • Argonne National Lab
    • Material Science Division, Argonne National Laboratory
    • Materials Science Division, Argonne National Laboratory
    • Argonne Natl Lab
    • Material Science, Argonne National Laboratory

  • Duck Young Chung

    • Argonne Natl Lab
    • Materials Science Division, Argonne National Laboratory
    • Materials Science Division, Argonne Natl Lab
    • Argonne National Laboratory
    • Material Science, Argonne National Laboratory

  • Mercouri Kanatzidis

    • Northwestern University
    • Materials Science Division, Argonne National Laboratory
    • Department of Chemistry, Northwestern University
    • Chemistry, Northwestern Univ

  • Daniel Pajerowski

    • Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
    • Oak Ridge National Lab
    • Oak Ridge National Laboratory

  • Guangyong Xu

    • Center of Neutron Research, National Institute of Standards and Technology
    • Neutron-Condensed Matter Science Group, National Institute of Standards and Technology
    • National Institute of Standards and Technology
    • NIST
    • Center for Neutron Research, National Institute of Standards and Technology
    • NIST Center for Neutron Research
    • Oak Ridge National Laboratory

  • Olivier Delaire

    • Duke University
    • Mechanical Engineering and Materials Science, Physics, Duke University