Luminescent properties of β-SiAlON:Eu²⁺ green phosphors synthesized by gas pressured sintering

Abstract

β-SiAlON: Eu²⁺ oxynitride green phosphors with compositions of Eu_xSi_6-zAl_zO_zN_8-z (x=0.0065 -0.0390, z=0.231) were successfully prepared using GPS (gas pressured sintering) method. The phase purity, microstructure, luminescent and thermal quenching properties for the prepared β-SiAlON:Eu²⁺ phosphors were investigated in detail. The prepared β-SiAlON:Eu²⁺ phosphor samples with Eu²⁺ doping concentration of x<0.0238 showed pure single β-SiAlON phase. The prepared β-SiAlON: Eu²⁺ phosphors absorbed UV-visible spectral region, and showed a single intense broadband emission in a range from 525 to 540 nm. The effects of the Eu²⁺ doping concentration on the optical properties for the β-SiAlON: Eu²⁺ phosphors were discussed under consideration of concentration quenching. The temperature dependence of photoluminescence (PL) properties was investigated from 25 to 300°C, and the activation energies (ΔE) for thermal quenching of the prepared β-SiAlON:Eu²⁺ phosphors were determined by Arrhenius fitting. The experimental results clearly indicates that the prepared β-SiAlON:Eu²⁺ has great potentials as a down-conversion green phosphor for white light emitting diodes (LEDs) utilizing near UV or blue LEDs as the primary light source.