Article Robust and orange-yellow-emitting Sr-rich polytypoid α-SiAlON (Sr3Si24Al6N40:Eu2+) phosphor for white LEDs

ESTILI Mehdi SAMURAI ORCID (Research Center for Electronic and Optical Materials/Optical Materials Field/Optical Ceramics Group, National Institute for Materials ScienceROR) ; Xie Rong-Jun (Xiamen University) ; TAKAHASHI Kohsei SAMURAI ORCID (Research Center for Electronic and Optical Materials/Optical Materials Field/Advanced Phosphor Group, National Institute for Materials ScienceROR) ; FUNAHASHI Shiro SAMURAI ORCID (Research Center for Electronic and Optical Materials/Optical Materials Field/Advanced Phosphor Group, National Institute for Materials ScienceROR) ; SUZUKI Tohru SAMURAI ORCID (Research Center for Electronic and Optical Materials/Optical Materials Field/Optical Ceramics Group, National Institute for Materials ScienceROR) ; HIROSAKI Naoto SAMURAI ORCID (Research Center for Electronic and Optical Materials/Optical Materials Field/Advanced Phosphor Group, National Institute for Materials ScienceROR)

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ESTILI Mehdi, Xie Rong-Jun, TAKAHASHI Kohsei, FUNAHASHI Shiro, SUZUKI Tohru, HIROSAKI Naoto. Robust and orange-yellow-emitting Sr-rich polytypoid α-SiAlON (Sr3Si24Al6N40:Eu2+) phosphor for white LEDs. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS. 2024, 25 (1), 2396276. https://doi.org/10.1080/14686996.2024.2396276
SAMURAI

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(abstract)

Nitrides and oxynitrides isostructural to α-Si3N4 (M-α-SiAlON, M = Sr, Ca, Li) possess
superb thermally stable photoluminescence (PL) properties, making them reliable
phosphors for high-power solid-state lighting. However, the synthesis of phase-pure Sr-αSiAlON still remains a great challenge and has only been reported for Sr below 1.35 at.%
as the large size of Sr2+ ions tends to destabilize the α-SiAlON structure. Here, we
succeeded to synthesize the single-phase powders of a unique “Sr-rich” polytypoid αSiAlON (Sr3Si24Al6N40:Eu2+) phosphor with three distinctive Sr/Eu luminescence sites
using a solid-state remixing-reannealing process. The Sr content of this polytypoid structure
exceeds those of a few previously reported structures by over 200%. The phase purity,
composition, structure, and PL properties of this phosphor were investigated. A single phase can be obtained by firing the stoichiometric mixtures of all-nitride precursors at
2050 °C under a 0.92 MPa N2 atmosphere. The Sr3Si24Al6N40:Eu2+ shows an intense
orange-yellow emission, with the emission maximum of 590 nm and internal/external
quantum efficiency of 66%/52% under 400 nm excitation. It also has a quite small thermal
quenching, maintaining 93% emission intensity at 150 °C. In comparison to Ca-αSiAlON:Eu2+, this Sr counterpart shows superior quantum efficiency and thermal stability,
enabling it to be an interesting orange-yellow down-conversion luminescent material for
white LEDs.

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Keyword: phosphors, nitrides, photoluminescence, powder synthesis, White light emitting diodes

Date published: 2024-12-31

Publisher: Taylor & Francis

Journal:

  • SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS (ISSN: 14686996) vol. 25 issue. 1 p. 1-19 2396276

Funding:

Manuscript type: Publisher's version (Version of record)

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First published URL: https://doi.org/10.1080/14686996.2024.2396276

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Updated at: 2024-09-25 16:30:35 +0900

Published on MDR: 2024-09-25 16:30:35 +0900

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