Abstract: The trivalent samarium doped Sr₂CeO₄ color-tunable phosphors were successfully synthesized by solid state reaction at 1200℃ for 6h and their luminescent characteristics were studied. The results indicate that the host can transfer its exciting energy to rare earth ion Sm³⁺ when excited with 365nm light. The emission color can be changed by tuning activator’s concentration in Sr₂CeO₄:Sm³⁺ phosphors. The doped compound emits strong white light when the concentration of the doped Sm³⁺ is lower than 3％. When the Sm³⁺ concentration is increased from 3％ to 15％, it emits red light. The chromaticity coordinate of Sr₂CeO₄: 1% Sm³⁺ phosphor is measured
to be (x, y) (0.334, 0.320), which is closed to the pure white (0.33, 0.33). It shows that Sr₂CeO₄: 1% Sm³⁺ phosphor is a promising single white phosphor for ultraviolet light-emitting diode.