High temperature degradation mechanism of a red phosphor, CaAlSiN3:Eu for solid-state lighting

Masatsugu Oishi, Shohei Shiomi, Takashi Yamamoto, Tomoyuki Ueki, Yoichiro Kai, Shigefusa F. Chichibu, Aiko Takatori, Kazunobu Kojima

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

Thermal properties of a red phosphor CaAlSiN3:Eu (CASN) at elevated temperatures were evaluated. A heat treatment at 800 °C degraded the photoluminescence property of CASN and caused irreversible changes in both the excitation and emission intensities. The heat treatment in air simultaneously decreased the N elements and increased the O elements. Consequently, the Eu2+ luminescence center was oxidized and CASN lost its photoluminescence property. Although the crystal structure of CASN host was stable even after the heat treatments, the local structure change around the Eu2+ ions is the origin of the thermal degradation of CASN. We found that the heat treatment in N2 atmosphere suppresses the thermal degradation. This is due to the suppression of N evolutions and the incorporation of O elements, which sustains the optically active Eu2+ state.

Original languageEnglish
Article number113104
JournalJournal of Applied Physics
Volume122
Issue number11
DOIs
Publication statusPublished - 2017 Sep 21

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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