Transparent Sialon phosphor ceramic plates for white light emitting diodes applications

Wide visible light emitting Sialon phosphor ceramic plates (PCPs) have been reported for Eu 2+ doped, and Gd 3+ and Pr 3+ co-doped systems fabricated by hot press sintering technique. The phase dependent luminescence for Eu 2+ doped PCPs is also presented in this work. Intense greenish-yellow luminescence at 552 nm wavelength under blue light excitation with the highest luminous efficacy of 58.78 lm/W was observed for β-Sialon PCP. Whereas, α-Sialon phase containing PCPs with Eu 2+ show orange luminescence at 590 nm wavelength under 460 nm wavelength excitation. The co-doping of Gd 3+ with Eu 2+ cations enhance the α-Sialon phase as well as transparency and even with a minimum content of Eu 2 O 3 (2 wt%) shows intense orange luminescence with luminous efficacy of 46.10 lm/W which is the highest among the orange emitting PCPs. The Gd 3+ co-doped with Pr 3+ without Eu 2+ PCP shows wide visible emission from cyan to red excited by 460 nm wavelength. Further, Gd 3+ and Pr 3+ were co-doped with Eu 2+ shows orange emission with a red shoulder emission. The PCPs coupled with 450 nm blue LED produces cool white light, day light and warm light corresponding to their phases and co-dopants.