Preparation and Luminescence Spectra of Calcium- and Rare-Earth (R = Eu, Tb, and Pr)-Codoped α-SiAlON Ceramics |
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Authors: | Rong-Jun Xie Mamoru Mitomo Kyota Uheda Fang-Fang Xu Yoshio Akimune |
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Affiliation: | Smart Structure Research Center, National Institute of Advanced Industrial Science and Technology, Umezono 1–1, Tsukuba, Ibaraki 305–8568, Japan;Advanced Materials Laboratory, National Institute for Materials Science, Namiki 1–1, Tsukuba, Ibaraki 305–0044, Japan;Department of Material Chemistry, Graduate School of Engineering, Tohoku University, Aramaki Aza Aoba, Sendai 980–8579, Japan |
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Abstract: | Rare-earth-doped oxynitride or nitride compounds have been reported to be luminescent and may then serve as new phosphors with good thermal and chemical stabilities. In this work, we report the photoluminescence (PL) spectra of europium-, terbium-, and praseodymium-doped Ca-α-SiAlON ceramics. The highly dense ceramics were prepared by hot pressing at 1750°C for 1 h under 20 MPa in a nitrogen atmosphere. Europium-doped Ca-α-SiAlON displayed a single broad emission band peaking at λ= 550–590 nm depending on the europium concentration. The emission bands in the spectra of europium-doped Ca-α-SiAlONs were assigned to the allowed transition of Eu2+ from the lowest crystal field component of 4 f 65 d to 8S7/2 (4 f 7) ground-state level. The emission spectra of terbium- and praseodymium-doped Ca-α-SiAlON ceramics both consisted of several sharp lines, which were attributed to the 5D4→7F j ( j = 3, 4, 5, 6) transitions of Tb3+ and 3P0→3H j ( j = 3, 4, 5) transitions of Pr3+, respectively. In particular, the terbium-doped α-SiAlON ceramics showed a strong green emission among these phosphors. |
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Keywords: | rare-earths luminescence microstructure SiAlON |
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