Phonon Interaction and Phase Transition in Single Formamidinium Lead Bromide Quantum Dots

Oliver Pfingsten, Julian Klein, Loredana Protesescu, Maryna I. Bodnarchuk, Maksym V. Kovalenko, Gerd Bacher

Research output: Contribution to journalArticleAcademicpeer-review

28 Citations (Scopus)

Abstract

Formamidinium lead bromide (FAPbBr(3)) quantum dots (QDs) are promising materials for light emitting applications in the visible spectral region because of their high photoluminescence (PL) quantum yield (QY) and the enhanced chemical stability as compared to, for instance, methylammonium based analogues. Toward practical harnessing of their compelling optical characteristics, the exciton recombination process, and in particular the exciton-phonon interaction and the impact of crystal phase transition, has to be understood in detail. This is addressed in this contribution by PL studies on single colloidal FAPbBr(3) QDs. Polarization resolved PL measurements reveal a fine structure splitting of excitonic transitions due to the Rashba effect. Distinct phonon replica have been observed within energetic distances of 4.3 +/- 0.5, 8.6 +/- 0.9, and 13.2 +/- 1.1 meV from the zero phonon line, which we attribute to vibrational modes of the lead bromide lattice. Additional vibrational modes of 18.6 +/- 0.3 and 38.8 +/- 1.1 meV are found and related to liberation modes of the formamidinium (FA) cation. Temperature-dependent PL spectra reveal a line broadening of the emission caused by exciton phonon interaction as well an unusual energy shift which is attributed to a crystal phase transition within the single QD.

Original languageEnglish
Pages (from-to)4440-4446
Number of pages7
JournalNano Letters
Volume18
Issue number7
DOIs
Publication statusPublished - Jul-2018
Externally publishedYes

Keywords

  • Formamidinium lead bromide
  • single quantum dots
  • phonon interaction
  • fine structure
  • phase transition
  • HALIDE PEROVSKITE NANOCRYSTALS
  • LIGHT-EMITTING-DIODES
  • EXCITON FINE-STRUCTURE
  • SOLAR-CELLS
  • PHOTON EMISSION
  • COLLOIDAL NANOCRYSTALS
  • CRYSTAL-STRUCTURE
  • DEFECT TOLERANCE
  • RESONANCE-RAMAN
  • CSPBBR3

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