Polaron self-localization in white-light emitting hybrid perovskites

Daniele Cortecchia, Jun Yin, Annalisa Bruno, Shu Zee Alencious Lo, Gagik G. Gurzadyan, Subodh Mhaisalkar, Jean Luc Brédas, Cesare Soci

Research output: Contribution to journalArticlepeer-review

149 Scopus citations

Abstract

Two-dimensional (2D) perovskites with the general formula APbX4 are attracting increasing interest as solution processable, white-light emissive materials. Recent studies have shown that their broadband emission is related to the formation of intra-gap colour centres. Here, we provide an in-depth description of the charge localization sites underlying the generation of such radiative centres and their corresponding decay dynamics, highlighting the formation of small polarons trapped within their lattice distortion field. Using a combination of spectroscopic techniques and first-principles calculations to study the white-light emitting 2D perovskites (EDBE)PbCl4 and (EDBE)PbBr4, we infer the formation of Pb23+, Pb3+, and X2 (where X = Cl or Br) species confined within the inorganic perovskite framework. Due to strong Coulombic interactions, these species retain their original excitonic character and form self-trapped polaron-excitons acting as radiative colour centres. These findings are expected to be relevant for a broad class of white-light emitting perovskites with large polaron relaxation energy.

Original languageEnglish (US)
Pages (from-to)2771-2780
Number of pages10
JournalJournal of Materials Chemistry C
Volume5
Issue number11
DOIs
StatePublished - 2017
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Chemistry

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