Synthesis and photoluminescence properties of Β-sialon: Eu2+ (Si6-z Alz Oz N8-z: Eu2+)

Divalent europium-activated Β -sialon (Si6-z Alz Oz N8-z, 0.1≤z≤2.0) phosphors with dopant concentration varying in the range of 0.02-1.5 mol % were synthesized by firing the powder mixture of α- Si3 N4, AlN, Al2 O3, and Eu2 O3 at 2000°C for 2 h under a nitrogen-gas pressure of 1.0 MPa. The phase purity, microstructure, luminescence spectra, and thermal quenching of the fired Β-sialon: Eu2+ phosphors were investigated. The samples with lower z values (z≤1.0) showed higher phase purity, finer and more uniform particle size, and higher emission. Green luminescence of Eu2+ (λem =528-550 nm) was achieved in Β -sialons upon near-ultraviolet (NUV) or blue-light excitations. Furthermore, the Β-sialon: Eu2+ phosphors had small thermal quenching, the emission intensity of which attained 84-87% of that measured at room temperature. The experimental data clearly indicates that Β-sialon: Eu2+ has great potentials as a down-conversion green phosphor for white light-emitting diodes (LEDs) utilizing NUV or blue LEDs as the primary light source.