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Exploring the Electronic Band Structure of Organometal Halide Perovskite via Photoluminescence Anisotropy of Individual Nanocrystals

Täuber, Daniela LU ; Dobrovolsky, Alexander LU ; Camacho Dejay, Rafael LU and Scheblykin, Ivan G. LU (2016) In Nano Letters 16(8). p.5087-5094
Abstract

Understanding electronic processes in organometal halide perovskites, flourishing photovoltaic, and emitting materials requires unraveling the origin of their electronic transitions. Light polarization studies can provide important information regarding transition dipole moment orientations. Investigating individual methylammonium lead triiodide perovskite nanocrystals enabled us to detect the polarization of photoluminescence intensity and photoluminescence excitation, hidden in bulk samples by ensemble averaging. Polarization properties of the crystals were correlated with their photoluminescence spectra and electron microscopy images. We propose that distortion of PbI6 octahedra leads to peculiarities of the electronic... (More)

Understanding electronic processes in organometal halide perovskites, flourishing photovoltaic, and emitting materials requires unraveling the origin of their electronic transitions. Light polarization studies can provide important information regarding transition dipole moment orientations. Investigating individual methylammonium lead triiodide perovskite nanocrystals enabled us to detect the polarization of photoluminescence intensity and photoluminescence excitation, hidden in bulk samples by ensemble averaging. Polarization properties of the crystals were correlated with their photoluminescence spectra and electron microscopy images. We propose that distortion of PbI6 octahedra leads to peculiarities of the electronic band structure close to the band-edge. Namely, the lowest band transition possesses a transition dipole moment along the apical Pb-I-Pb bond resulting in polarized photoluminescence. Excitation of photoluminescence above the bandgap is unpolarized because it involves molecular orbitals delocalized both in the apical and equatorial directions of the perovskite octahedron. Trap-assisted emission at 77 K, rather surprisingly, was polarized similar to the bandgap emission.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
band structure, fluorescence microscopy, individual nanocrystal, organometal halide perovskite, photoluminescence polarization, trap-assisted emission
in
Nano Letters
volume
16
issue
8
pages
8 pages
publisher
The American Chemical Society
external identifiers
  • scopus:84981509443
  • wos:000381331900050
ISSN
1530-6984
DOI
10.1021/acs.nanolett.6b02012
language
English
LU publication?
yes
id
ec60c902-18f8-499d-a265-04d0a9ab98b8
date added to LUP
2016-12-06 15:00:44
date last changed
2017-10-22 05:23:15
@article{ec60c902-18f8-499d-a265-04d0a9ab98b8,
  abstract     = {<p>Understanding electronic processes in organometal halide perovskites, flourishing photovoltaic, and emitting materials requires unraveling the origin of their electronic transitions. Light polarization studies can provide important information regarding transition dipole moment orientations. Investigating individual methylammonium lead triiodide perovskite nanocrystals enabled us to detect the polarization of photoluminescence intensity and photoluminescence excitation, hidden in bulk samples by ensemble averaging. Polarization properties of the crystals were correlated with their photoluminescence spectra and electron microscopy images. We propose that distortion of PbI<sub>6</sub> octahedra leads to peculiarities of the electronic band structure close to the band-edge. Namely, the lowest band transition possesses a transition dipole moment along the apical Pb-I-Pb bond resulting in polarized photoluminescence. Excitation of photoluminescence above the bandgap is unpolarized because it involves molecular orbitals delocalized both in the apical and equatorial directions of the perovskite octahedron. Trap-assisted emission at 77 K, rather surprisingly, was polarized similar to the bandgap emission.</p>},
  author       = {Täuber, Daniela and Dobrovolsky, Alexander and Camacho Dejay, Rafael and Scheblykin, Ivan G.},
  issn         = {1530-6984},
  keyword      = {band structure,fluorescence microscopy,individual nanocrystal,organometal halide perovskite,photoluminescence polarization,trap-assisted emission},
  language     = {eng},
  month        = {08},
  number       = {8},
  pages        = {5087--5094},
  publisher    = {The American Chemical Society},
  series       = {Nano Letters},
  title        = {Exploring the Electronic Band Structure of Organometal Halide Perovskite via Photoluminescence Anisotropy of Individual Nanocrystals},
  url          = {http://dx.doi.org/10.1021/acs.nanolett.6b02012},
  volume       = {16},
  year         = {2016},
}