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Abstract: Tunable white light of Eu2+ doped SiAlON crystal/glass composite phosphor with blue-yellow dual-emissions was demonstrated by variation of excitation wavelength in this work. The excitation properties of blue emission originated from the transition of Eu2+ ions in the Si–Al–B–O–N glass matrix and that of yellow emission originated from the transition of Eu2+ ions in the SiAlON lattice were investigated, respectively. By varying the excitation wavelength in the range of 330–380nm, white emission was tuned from cool white to warm white for this SiAlON crystal/glass composite phosphor owing to the various excitation properties of these two emission bands. Presented results indicate that this tunable SiAlON crystal/glass composite white-light phosphor might be applied in white LED, combining with UV chips with different emitting wavelengths in the range of 330–380nm. [Copyright &y& Elsevier]

Abstract: Cerium-doped Ca–α-SiAlON phosphors with Ca n−1.5x Si12−m−n Al m+n O n N16−n :Ce x (m=2n, 0.8≤m≤2.4, and 0.02≤x≤0.40) nominal compositions have been synthesized by gas pressure sintering (GPS). The photoluminescence (PL) properties were studied in relation to phase composition, particle morphology, and microstructure. Continuous addition of Ce rare-earth (RE) could enhance the emission intensity of phosphors, which was partially attributed to the formation of increased amount of planar defects where dense doping of Ce ions is achieved. Such enhancement could hold up to x=0.32, above which the emission intensity fell slightly due to the formation of more secondary phases and a surface glassy phase rather than concentration quenching. Finally, possible ways to improve the luminescence properties of Ce-doped α-SiAlON phosphors were discussed through tailoring the composition and microstructure. [Copyright &y& Elsevier]