Relationship between the Nature of Monovalent Cations and Charge Recombination in Metal Halide Perovskites

Katelyn A. Dagnall, Benjamin J. Foley, Shelby A. Cuthriell, Matthew R. Alpert, Xiaoyu Deng, Alexander Z. Chen, Zeming Sun, Mool C. Gupta, Kai Xiao, Seung Hun Lee, Ying Zhong Ma, Joshua J. Choi

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

We report charge recombination rates in lead iodide perovskites with alloys of formamidinium (FA) and methylammonium (MA) cations, FAxMA1-xPbI3, 0 ≤ x ≤ 0.9, prepared through ion exchange with minimal differences in morphology and charge trap density. Our results show that the trap-mediated recombination rate increases over 2 orders of magnitude with decreasing MA content. These results are consistent with a proposed mechanism that MA molecules are more effective in screening charged defects. In contrast, band-to-band charge recombination rates are minimized at an intermediate alloy composition. These findings reveal that the monovalent cations impact recombination processes through different mechanisms.

Original languageEnglish
Pages (from-to)1298-1304
Number of pages7
JournalACS Applied Energy Materials
Volume3
Issue number2
DOIs
StatePublished - Feb 24 2020

Funding

J.J.C. and S.-H.L. acknowledge support from the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award No. DE-SC0016144. The work at Oak Ridge National Laboratory (ORNL) was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division (Y.-Z.M.) and the U.S. Department of Energy Office of Science Graduate Student Research program (B.J.F).

Keywords

  • alloys
  • charge carrier recombination
  • ion exchange
  • perovskites
  • renewable energy materials
  • ultrafast spectroscopy

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