Mixing Matters: Nanoscale Heterogeneity and Stability in Metal Halide Perovskite Solar Cells

Laura Mundt, Fei Zhang, Axel Palmstrom, Junwei Xu, Robert Tirawat, Leah Kelly, Kevin Stone, Kai Zhu, Joseph Berry, Michael Toney, Laura Schelhas

Research output: Contribution to journalArticlepeer-review

21 Scopus Citations

Abstract

The structural stability of the metal halide perovskite (MHP) absorber material is crucial for the long-term solar cell stability in this thin-film photovoltaic technology. Here, we use mixed A-site FA0.83Cs0.17PbI3 to demonstrate that nanoscale compositional heterogeneity can serve as initiation sites for more macroscale, irreversible phase segregation, which causes device performance degradation. Probing compositional heterogeneity on length scales that has not been detected with conventional characterization techniques, we analyze the tetragonal to cubic phase transition behavior to indirectly determine the level of nanoscale compositional heterogeneity in the initial films. Further, we show that the thermal annealing conditions of the MHP layer during film processing influence the initial nanoscale compositional heterogeneity, and changing these processing conditions can be used to improve the device performance stability. The insights into structural degradation mechanisms initiated by nanoscale compositional heterogeneity and the proposed mitigation strategies will help guide the way toward long-term stable MHP solar cells.

Original languageAmerican English
Pages (from-to)471-480
Number of pages10
JournalACS Energy Letters
Volume7
Issue number1
DOIs
StatePublished - 2022

Bibliographical note

Publisher Copyright:
© 2021 American Chemical Society

NREL Publication Number

  • NREL/JA-5900-81467

Keywords

  • heterogeneous films
  • metal halide perovskites
  • nanoscale heterogeneity
  • stability parameter analyzer

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