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

作者：Kim Sun Woog^*; Hasegawa Takuya; Abe Takeshi; Nakagawa Hiroko; Hasegawa Shota; Seki Kohei; Toda Kenji^*; Uematsu Kazuyoshi; Ishigaki Tadashi; Sato Mineo

来源：Ceramics International, 2016, 42(8): 10389-10392.

DOI：10.1016/j.ceramint.2016.03.176

• Lanthanum oxysulfide phosphor
• Thermal decomposition method
• 0.6Li(2)SO(4)-0.4Na(2)SO(4)

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 0.6U(2)SO(4)-0.4Na(2)SO(4) 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)(2)O2S (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)(2)O2S (lambda(ex) = 270 nm) was 132% that of the commercial green-emitting phosphor (La0.52Ce0.31Tb0.17)PO4 (lambda(ex) = 285 nm), which shows the highest excitation absorption.

• 出版日期2016-6