Determination of the structural phase and octahedral rotation angle in halide perovskites

Roberto dos Reis, Hao Yang, Colin Ophus, Peter Ercius, Gregory Bizarri, Didier Perrodin, Tetiana Shalapska, Edith Bourret, Jim Ciston, Ulrich Dahmen

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

A key to the unique combination of electronic and optical properties in halide perovskite materials lies in their rich structural complexity. However, their radiation sensitive nature limits nanoscale structural characterization requiring dose efficient microscopic techniques in order to determine their structures precisely. In this work, we determine the space-group and directly image the Br halide sites of CsPbBr3, a promising material for optoelectronic applications. Based on the symmetry of high-order Laue zone reflections of convergent-beam electron diffraction, we identify the tetragonal (I4/mcm) structural phase of CsPbBr3 at cryogenic temperature. Electron ptychography provides a highly sensitive phase contrast measurement of the halide positions under low electron-dose conditions, enabling imaging of the elongated Br sites originating from the out-of-phase octahedral rotation viewed along the [001] direction of I4/mcm persisting at room temperature. The measurement of these features and comparison with simulations yield an octahedral rotation angle of 6.5°(±1.5°). The approach demonstrated here opens up opportunities for understanding the atomic scale structural phenomena applying advanced characterization tools on a wide range of radiation sensitive halide-based all-inorganic and hybrid organic-inorganic perovskites.

Original languageEnglish (US)
Article number071901
JournalApplied Physics Letters
Volume112
Issue number7
DOIs
StatePublished - Feb 12 2018

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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    dos Reis, R., Yang, H., Ophus, C., Ercius, P., Bizarri, G., Perrodin, D., Shalapska, T., Bourret, E., Ciston, J., & Dahmen, U. (2018). Determination of the structural phase and octahedral rotation angle in halide perovskites. Applied Physics Letters, 112(7), [071901]. https://doi.org/10.1063/1.5017537