Direct Observation of Bandgap Oscillations Induced by Optical Phonons in Hybrid Lead Iodide Perovskites

Peijun Guo, Yi Xia, Jue Gong, Duyen H. Cao, Xiaotong Li, Xun Li, Qi Zhang, Constantinos C. Stoumpos, Matthew S. Kirschner, Haidan Wen, Vitali B. Prakapenka, John B. Ketterson, Alex B.F. Martinson, Tao Xu, Mercouri G. Kanatzidis, Maria K.Y. Chan, Richard D. Schaller*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Hybrid organic–inorganic perovskites such as methylammonium lead iodide have emerged as promising semiconductors for energy-relevant applications. The interactions between charge carriers and lattice vibrations, giving rise to polarons, have been invoked to explain some of their extraordinary optoelectronic properties. Here, time-resolved optical spectroscopy is performed, with off-resonant pumping and electronic probing, to examine several representative lead iodide perovskites. The temporal oscillations of electronic bandgaps induced by coherent lattice vibrations are reported, which is attributed to antiphase octahedral rotations that dominate in the examined 3D and 2D hybrid perovskites. The off-resonant pumping scheme permits a simplified observation of changes in the bandgap owing to the Ag vibrational mode, which is qualitatively different from vibrational modes of other symmetries and without increased complexity of photogenerated electronic charges. The work demonstrates a strong correlation between the lead–iodide octahedral framework and electronic transitions, and provides further insights into the manipulation of coherent optical phonons and related properties in hybrid perovskites on ultrafast timescales.

Original languageEnglish (US)
Article number1907982
JournalAdvanced Functional Materials
Issue number22
StatePublished - May 1 2020


  • Raman scattering
  • coherent optical phonons
  • electron–phonon coupling
  • hybrid perovskites
  • transient optical spectroscopy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • General Chemistry
  • Condensed Matter Physics
  • General Materials Science
  • Electrochemistry
  • Biomaterials


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