Ultrafast Imaging of Carrier Cooling in Metal Halide Perovskite Thin Films

Sanghee Nah, Boris M. Spokoyny, Chan M.M. Soe, Constantinos C. Stoumpos, Mercouri G. Kanatzidis, Elad Harel*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


Understanding carrier relaxation in lead halide perovskites at the nanoscale is critical for advancing their device physics. Here, we directly image carrier cooling in polycrystalline CH3NH3PbI3 films with nanometer spatial resolution. We observe that upon photon absorption, highly energetic carriers rapidly thermalize with the lattice at different rates across the film. The initial carrier temperatures vary by many multiples of the lattice temperature across hundreds of nanometers, a factor that cannot be accounted for by excess photon energy above the bandgap alone or in variations of the initial carrier density. Electron microscopy suggests that morphology plays a critical role in determining the initial carrier temperature and that carriers in small crystal domains decay slower than those in large crystal domains. Our results demonstrate that local disorder dominates the observed carrier behavior, highlighting the importance of making local rather than averaged measurements in these materials.

Original languageEnglish (US)
Pages (from-to)1044-1048
Number of pages5
JournalNano letters
Issue number2
StatePublished - Feb 14 2018


  • Perovskite
  • carriers
  • cooling
  • microscopy
  • ultrafast

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering


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