Abstract: Spherical-like (Y,Bi)AG∶Eu³⁺ red phosphor powders with good photoluminescence performance were synthesized by chemical coprecipitation method. By using DTA-TGA and XRD, both the thermal decomposition and phase formation of (Y,Bi)AG∶Eu³⁺ precursors were investigated in process of calcination. The crystal structures, surface morphology and luminescence properties of the phosphors with different Bi³⁺ contents were characterized by means of XRD, SEM and fluorescence spectrometer. The result shows that the pure YAG crystal phase is formed after calcination at 1000℃ or above. The photoluminescence intensity of YAG∶Eu³⁺ red phosphor strengthens with increasing Bi³⁺ content due to the sensitizing of Bi³⁺ to Eu³⁺，but decreases by excessive Bi³⁺ ions. When the Bi3+ content is 0.0010, the photoluminescence intensity reaches the highest. Addition of Bi³⁺ cannot change the crystal structure of YAG∶Eu³⁺ phosphor, which is garnet with a little different lattice parameter. The particles of (Y,Bi)AG∶Eu³⁺ red phosphor are spherical-like shapes, narrow size distributions with no aggregation.

Key words: phosphor, garnet, co-precipitation, sensitization