Mixed Microscopic Eu2+ Occupancies in the Next-Generation Red LED Phosphor Sr[Li2Al2O2N2]:Eu2+ (SALON:Eu2+)

Freia Ruegenberg, Amador García-Fuente, Markus Seibald, Dominik Baumann, Gregor Hoerder, Tim Fiedler, Werner Urland, Hubert Huppertz, Andries Meijerink, Markus Suta*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Red-emitting narrow-band phosphors are of utmost importance for next-generation white-light phosphor-converted light-emitting diodes (pc-wLEDs) for improved efficacy and optimized correlated color temperatures. A promising representative crystallizing in an ordered variant of the UCr4C4 structure type is Sr[Li2Al2O2N2]:Eu2+ (SALON:Eu2+) emitting at a desirable wavelength of 614 nm. Despite an expected eightfold coordination of the Eu2+ ions by four N3− and O2− ions, respectively, the exact local coordination symmetry and a 1:1 ratio between the two types of ligands is not straightforwardly proven by X-ray diffraction. Low-temperature luminescence spectroscopy in conjunction with ligand field theory are powerful alternatives to resolve local features of Eu2+ as its excited 4f65d1 configuration reacts sensitively to the polarity of the ligands. The dominant emission at 614 nm shows pronounced vibronic fine structure at 10 K. In addition, weak emission bands can be resolved at 570 and 650 nm even at a low doping concentration of 0.5 mol% and are assigned to Eu2+ ions being eightfold coordinated by N3− and O2− ions in a ratio different from 1:1. Due to the feature of vierer ring-type channels in SALON:Eu2+, those Eu2+ centers are sufficiently close for mutual energy transfer, which is characterized by time-resolved luminescence at 10 K.

Original languageEnglish
Article number2202732
Number of pages11
JournalAdvanced Optical Materials
Volume11
Issue number9
DOIs
Publication statusPublished - 4 May 2023

Bibliographical note

Publisher Copyright:
© 2023 The Authors. Advanced Optical Materials published by Wiley-VCH GmbH.

Funding

M.S. is grateful for a material cost allowance from the Fonds der Chemischen Industrie e.V. and funding from the "Junges Kolleg" of the North‐Rhine Westphalian Academy of Sciences and Arts. A.G.‐F. acknowledges funding of the project PGC2018‐094783 (MCIU/AEI/FEDER, EU) and Asturias FICYT under grant AYUD/2021/51185 with the support of FEDER funds. Parts of this work are funded by the German Federal Ministry of Economic Affairs and Climate Action (Bundesministerium für Wirtschaft und Klimaschutz) in the frame of the Important Project of Common European Interest (IPCEI) on microelectronics. M.S. is grateful for a material cost allowance from the Fonds der Chemischen Industrie e.V. and funding from the "Junges Kolleg" of the North-Rhine Westphalian Academy of Sciences and Arts. A.G.-F. acknowledges funding of the project PGC2018-094783 (MCIU/AEI/FEDER, EU) and Asturias FICYT under grant AYUD/2021/51185 with the support of FEDER funds. Parts of this work are funded by the German Federal Ministry of Economic Affairs and Climate Action (Bundesministerium für Wirtschaft und Klimaschutz) in the frame of the Important Project of Common European Interest (IPCEI) on microelectronics. Open access funding enabled and organized by Projekt DEAL.

FundersFunder number
Asturias FICYTAYUD/2021/51185
Bundesministerium für Wirtschaft und Klimaschutz
German Federal Ministry of Economic Affairs and Climate Action
North-Rhine Westphalian Academy of Sciences and Arts
North‐Rhine Westphalian Academy of Sciences and ArtsPGC2018‐094783
Verband der Chemischen Industrie
Ministerio de Ciencia, Innovación y Universidades
European Commission
European Regional Development Fund
Agencia Estatal de Investigación

    Keywords

    • Eu
    • light-emitting diodes
    • narrow-band red emitter
    • Sr[Li Al O N ] (SALON)
    • UCr C -type phosphors

    Fingerprint

    Dive into the research topics of 'Mixed Microscopic Eu2+ Occupancies in the Next-Generation Red LED Phosphor Sr[Li2Al2O2N2]:Eu2+ (SALON:Eu2+)'. Together they form a unique fingerprint.

    Cite this