Determination of the True Lateral Grain Size in Organic-Inorganic Halide Perovskite Thin Films

Mengjin Yang, David Moore, Kai Zhu, Gordon MacDonald, Chelsea Heveran, Virginia Ferguson, Jason Killgore, Frank DelRio

Research output: Contribution to journalArticlepeer-review

16 Scopus Citations


In this letter, methylammonium lead iodide (MAPbI3) thin films were examined via piezoresponse force microscopy (PFM) and nanoindentation (NI) to determine if long-range atomic order existed across the full width and depth of the apparent grains. From the PFM, the piezoelectric response of the films was strongly correlated with low-index planes of the crystal structure and ferroelastic domains in macroscale solution-grown MAPbI3 crystals, which implied long-range order near the top surface. From the NI, it was found that the induced cracks were straight and extended across the full width of the apparent grains, which indicated that the long-range order was not limited to the near-surface region, but extended through the film thickness. Interestingly, the two MAPbI3 processes examined resulted in subtle differences in the extracted electro-mechanical and fracture properties, but exhibited similar power conversion efficiencies of >17% in completed devices.

Original languageAmerican English
Pages (from-to)33565-33570
Number of pages6
JournalACS Applied Materials and Interfaces
Issue number39
StatePublished - 4 Oct 2017

Bibliographical note

Publisher Copyright:
© 2017 American Chemical Society.

NREL Publication Number

  • NREL/JA-5K00-70187


  • Ferroelastic domains
  • Grain size
  • Nanoindentation
  • Perovskites
  • Photovoltaic devices
  • Piezoresponse force microscopy


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