Melt synthesis of oxide red phosphors

To synthesize various complex oxide materials and their solid solutions, we have applied a novel “meltsynthesis technique” rather than conventional solid-state reaction techniques. The synthesis of well-crystalline multi-component phosphor materials is sometimes difficult using conventional solid-state reaction techniques because the reaction rates are slow as a result of slow mutual diffusion among solid-state species, thereby creating an inhomogeneous product. However, the melt reaction is rapid and homogeneous as it proceeds because of a solution reaction with fast diffusion. Red-phosphor La2WO6:Eu3+ samples with 25 mol% Eu3+ were prepared in a short time using melt synthesis. Red emission was observed at 618 nm typical for the Eu3+ center. Meltsynthesized samples exhibited much higher emission intensities than those obtained for the sample prepared using a solid-state reaction.