Synthesis and photoluminescence properties of beta-sialon: Eu2+ (Si6-zAlzOzN8-z : Eu2+)

Divalent europium-activated beta-sialon (Si6-zAlzOzN8-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 alpha-Si3N4, AlN, Al2O3, and Eu2O3 at 2000 degrees 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 beta-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+ (lambda(em) = 528 - 550 nm) was achieved in beta-sialons upon near-ultraviolet (NUV) or blue-light excitations. Furthermore, the beta-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 beta-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. (c) 2007 The Electrochemical Society.