Monitoring a Silent Phase Transition in CH3NH3PbI3 Solar Cells via Operando X-ray Diffraction

Joseph Luther, Jeffrey Christians, Joseph Berry, Laura Schelhas, Michael Toney, Christopher Tassone, Kevin Stone

Research output: Contribution to journalArticlepeer-review

51 Scopus Citations

Abstract

The relatively modest temperature of the tetragonal-to-cubic phase transition in CH3NH3PbI3 perovskite is likely to occur during real world operation of CH3NH3PbI3 solar cells. In this work, we simultaneously monitor the structural phase transition of the active layer along with solar cell performance as a function of the device operating temperature. The tetragonal to cubic phase transition is observed in the working device to occur reversibly at temperatures between 60.5 and 65.4 °C. In these operando measurements, no discontinuity in the device performance is observed, indicating electronic behavior that is insensitive to the structural phase transition. This decoupling of device performance from the change in long-range order across the phase transition suggests that the optoelectronic properties are primarily determined by the local structure in CH3NH3PbI3. That is, while the average crystal structure as probed by X-ray diffraction shows a transition from tetragonal to cubic, the local structure generally remains well characterized by uncorrelated, dynamic octahedral rotations that order at elevated temperatures but are unchanged locally.

Original languageAmerican English
Pages (from-to)1007-1012
Number of pages6
JournalACS Energy Letters
Volume1
Issue number5
DOIs
StatePublished - 11 Nov 2016

Bibliographical note

Publisher Copyright:
© 2016 American Chemical Society.

NREL Publication Number

  • NREL/JA-5900-67115

Keywords

  • cubic
  • operando
  • perovskite
  • phase transition
  • solar cells
  • temperature
  • tetragonal
  • XRD

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