Synthesis and luminescent properties of Eu3+, Eu3+/Bi3+ and Gd3+ codoped YAG:Ce3+ phosphors and their potential applications in warm white light-emitting diodes

A series of YAG:Ce 3+ /Eu 3+ , YAG:Ce 3+ /Eu 3+ /Bi 3+ and YAG:Ce 3+ /Gd 3+ phosphors were synthesized by a co-precipitation method. The results suggest that all of phosphors have the cubic phase and nearly spherical morphology. However, the red emission can be produced by codoping Eu 3+ and Eu 3+ /Bi 3+ ions in YAG:Ce 3+ , and the codoped Gd 3+ ions can induce the red-shift of Ce 3+ emission. These results suggest that the Eu 3+ , Eu 3+ /Bi 3+ and Gd 3+ ions can be used to decrease the correlated color temperature and increase the color-rendering index of white light-emitting diodes based on InGaN blue chip and YAG:Ce 3+ phosphors.