Intrinsic Lead Ion Emissions in Zero-Dimensional Cs4PbBr6 Nanocrystals

Jun Yin, Yuhai Zhang, Annalisa Bruno, Cesare Soci, Osman M. Bakr, Jean Luc Brédas, Omar F. Mohammed

Research output: Contribution to journalArticlepeer-review

102 Scopus citations

Abstract

We investigate the intrinsic lead ion (Pb2+) emissions in zero-dimensional (0D) perovskite nanocrystals (NCs) using a combination of experimental and theoretical approaches. The temperature-dependent photoluminescence experiments for both "nonemissive" (highly suppressed green emission) and emissive (bright green emission) Cs4PbBr6 NCs show a splitting of emission spectra into high- and low-energy transitions in the ultraviolet (UV) spectral range. In the nonemissive case, we attribute the high-energy UV emission at approximately 350 nm to the allowed optical transition of 3P1 to 1S0 in Pb2+ ions and the low-energy UV emission at approximately 400 nm to the charge-transfer state involved in the 0D NC host lattice (D-state). In the emissive Cs4PbBr6 NCs, in addition to the broad UV emission, we demonstrate that energy transfer occurs from Pb2+ ions to green luminescent centers. The optical phonon modes in Cs4PbBr6 NCs can be assigned to both Pb-Br stretching and rocking motions from density functional theory calculations. Our results address the origin of the dual broadband Pb2+ ion emissions observed in Cs4PbBr6 NCs and provide insights into the mechanism of ionic exciton-optical phonon interactions in these 0D perovskites.

Original languageEnglish (US)
Pages (from-to)2805-2811
Number of pages7
JournalACS Energy Letters
Volume2
Issue number12
DOIs
StatePublished - Dec 8 2017
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry (miscellaneous)
  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Materials Chemistry

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