Anisotropic Electron-Phonon Interactions in 2D Lead-Halide Perovskites

Jaco J. Geuchies, Johan Klarbring, Lucia Di Virgilio, Shuai Fu, Sheng Qu, Guangyu Liu, Hai Wang, Jarvist M. Frost, Aron Walsh, Mischa Bonn, Heejae Kim

Research output: Contribution to journalArticlepeer-review

Abstract

Two-dimensional (2D) hybrid organic-inorganic metal halide perovskites offer enhanced stability for perovskite-based applications. Their crystal structure’s soft and ionic nature gives rise to strong interaction between charge carriers and ionic rearrangements. Here, we investigate the interaction of photogenerated electrons and ionic polarizations in single-crystal 2D perovskite butylammonium lead iodide (BAPI), varying the inorganic lamellae thickness in the 2D single crystals. We determine the directionality of the transition dipole moments (TDMs) of the relevant phonon modes (in the 0.3-3 THz range) by the angle- and polarization-dependent THz transmission measurements. We find a clear anisotropy of the in-plane photoconductivity, with a ∼10% reduction along the axis parallel with the transition dipole moment of the most strongly coupled phonon. Detailed calculations, based on Feynman polaron theory, indicate that the anisotropy originates from directional electron-phonon interactions.

Original languageEnglish
Pages (from-to)8642-8649
Number of pages8
JournalNano Letters
Volume24
Issue number28
DOIs
StatePublished - 17 Jul 2024

Bibliographical note

Publisher Copyright:
© 2024 The Authors. Published by American Chemical Society.

Keywords

  • Low-dimensional perovskites
  • electron−phonon coupling
  • polarons
  • ultrafast THz spectroscopy

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