Synthesis of Y[sub 2]O[sub 3]:Eu, Bi Red Phosphors by Homogeneous Coprecipitation and Their Photoluminescence Behaviors

Bismuth-doped is used as red phosphors with very high efficiency and appropriate emission wavelength. These red phosphors have been synthesized by homogeneous coprecipitation and solid-state reaction without any flux, which may be used in the field of white LEDs (light-emitting diodes). The crystal structure of bismuth-doped is cubic (space group: ) with and sites. can be excited by charge transfer and direct excitation (about ). When incorporated in phosphors, ions act as a sensitizer for ions under radiation. The energy transferred from ions to ions by a nonradiation process resulted in the final emission from excited ions. The emission is observed at , which is due to the electric dipole transition induced by the lack of inversion symmetry ( site). Moreover, luminescence intensity of , Bi increases with sintering temperature. Bismuth concentration dependence energy transfer rate and color purity have been observed in this investigation.