White-emission in single-phase Ba 2 Gd 2 Si 4 O 13 :Ce 3+ ,Eu 2+ ,Sm 3+ phosphor for white-LEDs.

To develop new white-light-emitting phosphor, a series of Ce3+ -Eu2+ -Sm3+ doped Ba2 Gd2 Si4 O13 (BGS) phosphors were prepared by the solid-state reaction method, and their photoluminescence properties were studied. The Ce3+ and Eu2+ single-doped BGS show broad emission bands around in the region of 350-550 and 420-650nm, respectively. By co-doping Ce3+ -Eu2+ into BGS, the energy transfer (ET) from Ce3+ to Eu2+ is inefficient, which could be due to the competitive absorption between the two activator ions. The Sm3+ -activated BGS exhibits an orangey-red emission in the region of 550-750nm. To achieve white emission, the BGS:0.06Ce3+ ,0.04Eu2+ ,ySm3+ (0≤y≤0.18) phosphors were designed, in which the ET from Ce3+ /Eu2+ to Sm3+ was observed. The emission color can be tuned by controlling the Sm3+ concentration, and white emission was obtained in the BGS:0.06Ce3+ ,0.04Eu2+ ,0.06Sm3+ sample. The investigation of thermal luminescence stability for the typical BGS:0.06Ce3+ ,0.04Eu2+ ,0.06Sm3+ sample reveals that the emission intensities of both Eu2+ and Sm3+ demonstrate continuous decrease but the Ce3+ emission is enhanced gradually with increasing temperature. The corresponding reason has been discussed.