Origin of Broad-Band Emission and Impact of Structural Dimensionality in Tin-Alloyed Ruddlesden-Popper Hybrid Lead Iodide Perovskites

Matthew Beard, Xihan Chen, Haipeng Lu, Tianyang Li, Xiaoming Wang, Yanfa Yan, David Mitzi

Research output: Contribution to journalArticlepeer-review

56 Scopus Citations

Abstract

Hybrid organic-inorganic lead halide perovskites have shown promising results as active layers in light-emitting diodes, typically utilizing the near-monochromatic, free exciton emission. Some perovskite compounds, however, show broad-band emission that is more intense than the free exciton counterpart. In this study, we show that the light emission properties of Ruddlesden-Popper hybrid perovskites PEA2MAn-1PbnI3n+1 (PEA = phenethylammonium, MA = methylammonium) can be tuned by Sn alloying and are highly sensitive to Sn %. With increasing dimensionality, the broad-band emission quantum yield decreases drastically, from 23% in n = 1 to <1% for the n = 3 compound. Using density functional theory calculations and transient reflectance spectroscopy, the broad emission is identified as originating from self-trapped excitons. A dynamic picture of the formation process is also presented, for which ultrafast (<5 ps) hole-trapping at the Sn site is the first step, followed by electron localization from Coulombic interaction. These findings are especially valuable for designing perovskite materials with intense room-temperature broad-band emission for solid-state lighting applications.

Original languageAmerican English
Pages (from-to)347-352
Number of pages6
JournalACS Energy Letters
Volume5
Issue number2
DOIs
StatePublished - 2020

Bibliographical note

Publisher Copyright:
© 2019 American Chemical Society.

NREL Publication Number

  • NREL/JA-5900-75462

Keywords

  • hybrid perovskite
  • transient reflectance
  • white light emission

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