The promising green oxynitride phosphor, Ba3Si6O12N2:Eu(2+), was synthesized at 1350 °C for 5 hours under a reducing N2/H2 (5%) atmosphere by using the solid-state reaction method. The phase purity was investigated by varying the nominal compositions, and the pure phase was achieved by carefully controlling the Si/Ba and O/Ba ratios. The phosphor displayed a broad excitation band spanning from the ultraviolet (UV) to the blue spectral region, and showed a single symmetrical emission band peaking at 525 nm with a full width at half maximum (FWHM) of ∼ 68 nm. The as-prepared green phosphor exhibited a small thermal quenching, which remained 90% of the initial emission intensity when measured at 200 °C. The internal and external quantum efficiencies measured under 450 nm excitation were 68 and 38%, respectively. Color temperature-tunable white LEDs with a high color rendering index of Ra = 88-94 were attained by combining the prepared green phosphor and a red phosphor Sr2Si5N8:Eu(2+) with a blue LED chip.

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A novel Y 3Àx Si 6 N 11 : xCe 3+ yellow phosphor was synthesized using the carbothermal reduction and nitridition method at 1550°C for 16 h in this letter. Photoluminescence spectra indicated that the phosphor showed broad excitation spectrum and had strong absorption in range of 350-450 nm. It also gave a broad emission band (Full width at half maximum = 153 nm) centered at 575 nm under 425-nm excitation. With increasing Ce 3+ concentration, the strongest emission intensity was obtained at 5 mol% Ce 3+ doping amount and a systematic redshift was observed as the Ce 3+ concentration increased. The results indicate that this novel yellow phosphor is a promising candidate for using in blue-chip-excited white light-emitting diodes (LEDs).