Self-emitting blue and red EuOX (X = F, Cl, Br, I) materials

Band structure, charge transfer energy, and emission energy

Donghyeon Kim, Jae Ryeol Jeong, Yujin Jang, Jong Seong Bae, In Chung, Runli Liang, Dong Kyun Seo, Seung Joo Kim, Jung Chul Park

Research output: Contribution to journalArticle

Abstract

Self-emitting blue and red EuOX (X = F, Cl, Br, and I) were successfully synthesized and characterized. Far-infrared and Raman measurements revealed that the vibration modes prominently reflected the Eu-O and Eu-X bond characters of these materials. X-ray photoelectron spectroscopy (XPS) of the red-emitting EuOX compounds showed that Eu exclusively existed as Eu3+, while in the blue-emitting EuOX, a mixed Eu3+/Eu2+ state was observed. For the red-emitting EuOX (X = F, Cl, and Br), the maximum wavelengths of the charge-transfer (CT) bands were red-shifted: F → Cl → Br (282, 320, and 330 nm for F, Cl, and Br, respectively). Using one-electron spin-polarized band structure calculations, it was verified that the red-shift of the CT energy from F to Br in EuOX was mainly due to the relative positions of the halogen orbital energies being gradually increased, following the trend in their electronegativity. For the blue-emitting EuOX (X = Cl, Br, and I), the emission band maxima were red-shifted from Cl to I (409, 414, and 432 nm for Cl, Br, and I, respectively), which was quite opposite to the trend predicted based on the spectrochemical series in crystal field theory, which was in good agreement with the previous results of the calculated 5d → 4f transition energies of the Eu2+ activator based on the crystal field theory. Through photoluminescence, UV-visible absorbance, and XPS, it was elucidated that the red emission due to Eu3+ was strongly masked by the intensified blue emission associated with the small amount of Eu2+ in the blue-emitting EuOX (X = Cl, Br, and I). These materials may provide a platform for modeling new phosphors for application in solid-state lighting.

Original languageEnglish
Pages (from-to)1737-1749
Number of pages13
JournalPhysical Chemistry Chemical Physics
Volume21
Issue number4
DOIs
Publication statusPublished - Jan 1 2019

Fingerprint

Band structure
Charge transfer
X ray photoelectron spectroscopy
charge transfer
Electronegativity
Crystals
Halogens
crystal field theory
photoelectron spectroscopy
Phosphors
trends
Photoluminescence
Lighting
Infrared radiation
red shift
electron spin
Wavelength
illuminating
halogens
phosphors

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Cite this

Self-emitting blue and red EuOX (X = F, Cl, Br, I) materials : Band structure, charge transfer energy, and emission energy. / Kim, Donghyeon; Jeong, Jae Ryeol; Jang, Yujin; Bae, Jong Seong; Chung, In; Liang, Runli; Seo, Dong Kyun; Kim, Seung Joo; Park, Jung Chul.

In: Physical Chemistry Chemical Physics, Vol. 21, No. 4, 01.01.2019, p. 1737-1749.

Research output: Contribution to journalArticle

Kim, Donghyeon ; Jeong, Jae Ryeol ; Jang, Yujin ; Bae, Jong Seong ; Chung, In ; Liang, Runli ; Seo, Dong Kyun ; Kim, Seung Joo ; Park, Jung Chul. / Self-emitting blue and red EuOX (X = F, Cl, Br, I) materials : Band structure, charge transfer energy, and emission energy. In: Physical Chemistry Chemical Physics. 2019 ; Vol. 21, No. 4. pp. 1737-1749.
@article{8a66c8b84acc466c88512b3c440b3b37,
title = "Self-emitting blue and red EuOX (X = F, Cl, Br, I) materials: Band structure, charge transfer energy, and emission energy",
abstract = "Self-emitting blue and red EuOX (X = F, Cl, Br, and I) were successfully synthesized and characterized. Far-infrared and Raman measurements revealed that the vibration modes prominently reflected the Eu-O and Eu-X bond characters of these materials. X-ray photoelectron spectroscopy (XPS) of the red-emitting EuOX compounds showed that Eu exclusively existed as Eu3+, while in the blue-emitting EuOX, a mixed Eu3+/Eu2+ state was observed. For the red-emitting EuOX (X = F, Cl, and Br), the maximum wavelengths of the charge-transfer (CT) bands were red-shifted: F → Cl → Br (282, 320, and 330 nm for F, Cl, and Br, respectively). Using one-electron spin-polarized band structure calculations, it was verified that the red-shift of the CT energy from F to Br in EuOX was mainly due to the relative positions of the halogen orbital energies being gradually increased, following the trend in their electronegativity. For the blue-emitting EuOX (X = Cl, Br, and I), the emission band maxima were red-shifted from Cl to I (409, 414, and 432 nm for Cl, Br, and I, respectively), which was quite opposite to the trend predicted based on the spectrochemical series in crystal field theory, which was in good agreement with the previous results of the calculated 5d → 4f transition energies of the Eu2+ activator based on the crystal field theory. Through photoluminescence, UV-visible absorbance, and XPS, it was elucidated that the red emission due to Eu3+ was strongly masked by the intensified blue emission associated with the small amount of Eu2+ in the blue-emitting EuOX (X = Cl, Br, and I). These materials may provide a platform for modeling new phosphors for application in solid-state lighting.",
author = "Donghyeon Kim and Jeong, {Jae Ryeol} and Yujin Jang and Bae, {Jong Seong} and In Chung and Runli Liang and Seo, {Dong Kyun} and Kim, {Seung Joo} and Park, {Jung Chul}",
year = "2019",
month = "1",
day = "1",
doi = "10.1039/c8cp06470a",
language = "English",
volume = "21",
pages = "1737--1749",
journal = "Physical Chemistry Chemical Physics",
issn = "1463-9076",
publisher = "Royal Society of Chemistry",
number = "4",

}

TY - JOUR

T1 - Self-emitting blue and red EuOX (X = F, Cl, Br, I) materials

T2 - Band structure, charge transfer energy, and emission energy

AU - Kim, Donghyeon

AU - Jeong, Jae Ryeol

AU - Jang, Yujin

AU - Bae, Jong Seong

AU - Chung, In

AU - Liang, Runli

AU - Seo, Dong Kyun

AU - Kim, Seung Joo

AU - Park, Jung Chul

PY - 2019/1/1

Y1 - 2019/1/1

N2 - Self-emitting blue and red EuOX (X = F, Cl, Br, and I) were successfully synthesized and characterized. Far-infrared and Raman measurements revealed that the vibration modes prominently reflected the Eu-O and Eu-X bond characters of these materials. X-ray photoelectron spectroscopy (XPS) of the red-emitting EuOX compounds showed that Eu exclusively existed as Eu3+, while in the blue-emitting EuOX, a mixed Eu3+/Eu2+ state was observed. For the red-emitting EuOX (X = F, Cl, and Br), the maximum wavelengths of the charge-transfer (CT) bands were red-shifted: F → Cl → Br (282, 320, and 330 nm for F, Cl, and Br, respectively). Using one-electron spin-polarized band structure calculations, it was verified that the red-shift of the CT energy from F to Br in EuOX was mainly due to the relative positions of the halogen orbital energies being gradually increased, following the trend in their electronegativity. For the blue-emitting EuOX (X = Cl, Br, and I), the emission band maxima were red-shifted from Cl to I (409, 414, and 432 nm for Cl, Br, and I, respectively), which was quite opposite to the trend predicted based on the spectrochemical series in crystal field theory, which was in good agreement with the previous results of the calculated 5d → 4f transition energies of the Eu2+ activator based on the crystal field theory. Through photoluminescence, UV-visible absorbance, and XPS, it was elucidated that the red emission due to Eu3+ was strongly masked by the intensified blue emission associated with the small amount of Eu2+ in the blue-emitting EuOX (X = Cl, Br, and I). These materials may provide a platform for modeling new phosphors for application in solid-state lighting.

AB - Self-emitting blue and red EuOX (X = F, Cl, Br, and I) were successfully synthesized and characterized. Far-infrared and Raman measurements revealed that the vibration modes prominently reflected the Eu-O and Eu-X bond characters of these materials. X-ray photoelectron spectroscopy (XPS) of the red-emitting EuOX compounds showed that Eu exclusively existed as Eu3+, while in the blue-emitting EuOX, a mixed Eu3+/Eu2+ state was observed. For the red-emitting EuOX (X = F, Cl, and Br), the maximum wavelengths of the charge-transfer (CT) bands were red-shifted: F → Cl → Br (282, 320, and 330 nm for F, Cl, and Br, respectively). Using one-electron spin-polarized band structure calculations, it was verified that the red-shift of the CT energy from F to Br in EuOX was mainly due to the relative positions of the halogen orbital energies being gradually increased, following the trend in their electronegativity. For the blue-emitting EuOX (X = Cl, Br, and I), the emission band maxima were red-shifted from Cl to I (409, 414, and 432 nm for Cl, Br, and I, respectively), which was quite opposite to the trend predicted based on the spectrochemical series in crystal field theory, which was in good agreement with the previous results of the calculated 5d → 4f transition energies of the Eu2+ activator based on the crystal field theory. Through photoluminescence, UV-visible absorbance, and XPS, it was elucidated that the red emission due to Eu3+ was strongly masked by the intensified blue emission associated with the small amount of Eu2+ in the blue-emitting EuOX (X = Cl, Br, and I). These materials may provide a platform for modeling new phosphors for application in solid-state lighting.

UR - http://www.scopus.com/inward/record.url?scp=85060381468&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85060381468&partnerID=8YFLogxK

U2 - 10.1039/c8cp06470a

DO - 10.1039/c8cp06470a

M3 - Article

VL - 21

SP - 1737

EP - 1749

JO - Physical Chemistry Chemical Physics

JF - Physical Chemistry Chemical Physics

SN - 1463-9076

IS - 4

ER -