Phase Purity and Luminescence Properties of Fine Ca-α-SiAlON:Eu Phosphors Synthesized by Gas Reduction Nitridation Method

This paper reports a simple, inexpensive, and efficient synthetic route to -based yellow phosphors for white light-emitting diodes. Through direct gas reduction and nitridation of the homogeneous oxide precursor of , fine phosphors were obtained by one-step firing at for 4 h in the flowing and mixture gas. The dependence of the structural characterization and optical properties on the overall composition of the host lattice has been investigated. A nearly single-phase can be synthesized by controlling the overall composition of the host lattice at and . The strongest luminescence is achieved at about and . Further improvement of the powder characteristics was attained by post heat-treatment at for 2 h under 5 atm of by gas-pressure sintering. The post-treated powders showed a pure phase at . The phosphor exhibits a high crystallinity, high luminescence intensity, high quantum efficiency, and very low thermal quenching, which is better than those prepared by the conventional solid-state reaction.