Abnormal improvement in emission of lanthanum oxysulfide phosphor La2O2S:Tb3+ synthesized by a novel method, thermal decomposition in eutectic molten salt

Sun Woog Kim, Takuya Hasegawa, Takeshi Abe, Hiroko Nakagawa, Shota Hasegawa, Kohei Seki, Kenji Toda, Kazuyoshi Uematsu, Tadashi Ishigaki, Mineo Sato

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

The lanthanum oxysulfide phosphor La2O2S:Tb3+ is generally synthesized by the direct sulfidation of La2O3 using H2S or CS2 gas. However, these gases are known to be highly toxic to humans. In this paper, a new synthesis method that uses 0.6Li2SO4-0.4Na2SO4 as the flux is proposed for obtaining La2O2S:Tb3+ phosphor, without the need for H2S or CS2 gas. The proposed method consists of two steps: 1) oxidation to obtain La2O2SO4 and 2) reduction to reduce La2O2SO4 to La2O2S. Using this novel method, (La1-xTbx)2O2S (0.01≤x≤0.13) were successfully synthesized in a single-phase form. The synthesized phosphors exhibited extraordinary luminescence behavior. Further, despite their low Tb3+ ion content, the phosphors showed high emission intensities. The relative emission intensity of (La0.95Tb0.05)2O2S (λex=270 nm) was 132% that of the commercial green-emitting phosphor (La0.52Ce0.31Tb0.17)PO4ex=285 nm), which shows the highest excitation absorption.

Original languageEnglish
Pages (from-to)10389-10392
Number of pages4
JournalCeramics International
Volume42
Issue number8
DOIs
Publication statusPublished - 2016 Jun 1
Externally publishedYes

Keywords

  • 0.6LiSO-0.4NaSO
  • Lanthanum oxysulfide phosphor
  • Thermal decomposition method

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Process Chemistry and Technology
  • Surfaces, Coatings and Films
  • Materials Chemistry

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