Ghent University Academic Bibliography

Advanced

Charge transfer induced energy storage in CaZnOS:Mn : insight from experimental and computational spectroscopy

Jonas Joos UGent, Kurt Lejaeghere UGent, Katleen Korthout UGent, Ang Feng UGent, Dirk Poelman UGent and Philippe Smet UGent (2017) PHYSICAL CHEMISTRY CHEMICAL PHYSICS. 19(13). p.9075-9085
abstract
CaZnOS: Mn2+ is a rare-earth-free luminescent compound with an orange broadband emission at 612 nm, featuring pressure sensing capabilities, often explained by defect levels where energy can be stored. Despite recent efforts from experimental and theoretical points of view, the underlying luminescence mechanisms in this phosphor still lack a profound understanding. By the evaluation of thermoluminescence as a function of the charging wavelength, we probe the defect levels allowing energy storage. Multiple trap depths and trapping routes are found, suggesting predominantly local trapping close to Mn2+ impurities. We demonstrate that this phosphor shows mechanoluminescence which is unexpectedly stable at high temperature (up to 200 degrees C), allowing pressure sensing in a wide temperature range. Next, we correlate the spectroscopic results with a theoretical study of the electronic structure and stability of the Mn defects in CaZnOS. DFT calculations at the PBE+U level indicate that Mn impurities are incorporated on the Zn site in a divalent charge state, which is confirmed by X-ray absorption spectroscopy (XAS). Ligand-to-metal charge transfer (LMCT) is predicted from the location of the Mn impurity levels, obtained from the calculated defect formation energies. This LMCT proves to be a very efficient pathway for energy storage. The excited state landscape of the Mn2+ 3d(5) electron configuration is assessed through the spin-correlated crystal field and a good correspondence with the emission and excitation spectra is found. In conclusion, studying phosphors at both a singleparticle level (i.e. via calculation of defect formation energies) and a many-particle level (i.e. by accurately localizing the excited states) is necessary to obtain a complete picture of luminescent defects, as demonstrated in the case of CaZnOS: Mn2+.
Please use this url to cite or link to this publication:
author
organization
year
type
journalArticle (original)
publication status
published
subject
keyword
luminescence, mechanoluminescence, manganese, crystal field theory, DFT, modeling, charge transfer, DENSITY-FUNCTIONAL THEORY, RARE-EARTH IONS, VIBRONIC SPECTRA, AB-INITIO, LUMINESCENCE PROPERTIES, ALKALI-HALIDES, LIGAND-FIELD, PHOSPHORS, 1ST-PRINCIPLES, LANTHANIDE
journal title
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
Phys. Chem. Chem. Phys.
volume
19
issue
13
pages
9075 - 9085
Web of Science type
Article
Web of Science id
000399004700049
ISSN
1463-9076
1463-9084
DOI
10.1039/c7cp00285h
project
Center for nano- and biophotonics (NB-Photonics)
language
English
UGent publication?
yes
classification
A1
copyright statement
I have retained and own the full copyright for this publication
id
8519876
handle
http://hdl.handle.net/1854/LU-8519876
date created
2017-05-09 08:58:36
date last changed
2017-05-12 08:04:40
@article{8519876,
  abstract     = {CaZnOS: Mn2+ is a rare-earth-free luminescent compound with an orange broadband emission at 612 nm, featuring pressure sensing capabilities, often explained by defect levels where energy can be stored. Despite recent efforts from experimental and theoretical points of view, the underlying luminescence mechanisms in this phosphor still lack a profound understanding. By the evaluation of thermoluminescence as a function of the charging wavelength, we probe the defect levels allowing energy storage. Multiple trap depths and trapping routes are found, suggesting predominantly local trapping close to Mn2+ impurities. We demonstrate that this phosphor shows mechanoluminescence which is unexpectedly stable at high temperature (up to 200 degrees C), allowing pressure sensing in a wide temperature range. Next, we correlate the spectroscopic results with a theoretical study of the electronic structure and stability of the Mn defects in CaZnOS. DFT calculations at the PBE+U level indicate that Mn impurities are incorporated on the Zn site in a divalent charge state, which is confirmed by X-ray absorption spectroscopy (XAS). Ligand-to-metal charge transfer (LMCT) is predicted from the location of the Mn impurity levels, obtained from the calculated defect formation energies. This LMCT proves to be a very efficient pathway for energy storage. The excited state landscape of the Mn2+ 3d(5) electron configuration is assessed through the spin-correlated crystal field and a good correspondence with the emission and excitation spectra is found. In conclusion, studying phosphors at both a singleparticle level (i.e. via calculation of defect formation energies) and a many-particle level (i.e. by accurately localizing the excited states) is necessary to obtain a complete picture of luminescent defects, as demonstrated in the case of CaZnOS: Mn2+.},
  author       = {Joos, Jonas and Lejaeghere, Kurt and Korthout, Katleen and Feng, Ang and Poelman, Dirk and Smet, Philippe},
  issn         = {1463-9076},
  journal      = {PHYSICAL CHEMISTRY CHEMICAL PHYSICS},
  keyword      = {luminescence,mechanoluminescence,manganese,crystal field theory,DFT,modeling,charge transfer,DENSITY-FUNCTIONAL THEORY,RARE-EARTH IONS,VIBRONIC SPECTRA,AB-INITIO,LUMINESCENCE PROPERTIES,ALKALI-HALIDES,LIGAND-FIELD,PHOSPHORS,1ST-PRINCIPLES,LANTHANIDE},
  language     = {eng},
  number       = {13},
  pages        = {9075--9085},
  title        = {Charge transfer induced energy storage in CaZnOS:Mn : insight from experimental and computational spectroscopy},
  url          = {http://dx.doi.org/10.1039/c7cp00285h},
  volume       = {19},
  year         = {2017},
}

Chicago
Joos, Jonas, Kurt Lejaeghere, Katleen Korthout, Ang Feng, Dirk Poelman, and Philippe Smet. 2017. “Charge Transfer Induced Energy Storage in CaZnOS:Mn : Insight from Experimental and Computational Spectroscopy.” Physical Chemistry Chemical Physics 19 (13): 9075–9085.
APA
Joos, J., Lejaeghere, K., Korthout, K., Feng, A., Poelman, D., & Smet, P. (2017). Charge transfer induced energy storage in CaZnOS:Mn : insight from experimental and computational spectroscopy. PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 19(13), 9075–9085.
Vancouver
1.
Joos J, Lejaeghere K, Korthout K, Feng A, Poelman D, Smet P. Charge transfer induced energy storage in CaZnOS:Mn : insight from experimental and computational spectroscopy. PHYSICAL CHEMISTRY CHEMICAL PHYSICS. 2017;19(13):9075–85.
MLA
Joos, Jonas, Kurt Lejaeghere, Katleen Korthout, et al. “Charge Transfer Induced Energy Storage in CaZnOS:Mn : Insight from Experimental and Computational Spectroscopy.” PHYSICAL CHEMISTRY CHEMICAL PHYSICS 19.13 (2017): 9075–9085. Print.