Metal Halide Perovskites Demonstrate Radiation Hardness and Defect Healing in Vacuum

Michael Holland, Anthony Ruth, Kamil Mielczarek, Vivek Dhas, Joseph Berry, Michael Irwin

Research output: Contribution to journalArticlepeer-review

8 Scopus Citations

Abstract

Herein, we subject formamidinium lead iodide films to oxygen-containing gases (flowing O2 or free diffusion of lab atmosphere), inert gases (flowing He, Ar, or N2), and vacuum. Our films are irradiated by Cu Kα X-rays and held at 75 °C while X-ray diffraction is recorded. Under all gas conditions, we observe a reproducible 1.1 ± 0.5 Å3 perovskite lattice contraction from an initial unit cell volume of 256.5 ± 0.8 Å3 concurrent with continuous perovskite loss and lead iodide growth. Oxygen-containing gases increase the reaction rates without materially altering perovskite structural changes. Under the same temperature and irradiation conditions in vacuo, a self-healing reaction is observed, exhibited by a reproducible (0.9 ± 0.3 Å3) lattice expansion and stabilization of the perovskite. Interactions between the perovskite, defects, and minority phases are simulated by generalized gradient approximation Perdew-Burke-Ernzerhof (GGA-PBE) density functional theory. Lattice contraction indicates an increase in the concentration of Schottky defects-pairs of formamidinium and iodine vacancies. Under irradiation in every atmospheric condition, a solid solution of Schottky defects with a concentration of several percent diffuses and precipitates forming lead iodide and consuming the defects. In the presence of ionized gases, this framework is modified to include the continual loss of formamidinium and iodine ions from the perovskite forming Schottky defects.

Original languageAmerican English
Pages (from-to)9352-9362
Number of pages11
JournalACS Applied Materials and Interfaces
Volume14
Issue number7
DOIs
StatePublished - 23 Feb 2022

Bibliographical note

Publisher Copyright:
© 2022 American Chemical Society.

NREL Publication Number

  • NREL/JA-5K00-78648

Keywords

  • environmental degradation
  • in vacuo
  • ion migration
  • perovskites
  • photovoltaics
  • Schottky defects
  • X-ray diffraction

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