Effects of doping $$\hbox {Pr}³⁺$$ Pr 3 + and $$\hbox {Gd}³⁺$$ Gd 3 + into YAG:Ce phosphors on the luminescence properties

A series of ((hbox {Y}_0.98-x-yhbox {Ce}_0.02hbox {Pr}_xhbox {Gd}_y)₃hbox {Al}₅hbox {O}₁₂) ((x=0{-}0.02), (y=0,,0.3)) phosphors were prepared by a modified co-precipitation method. The phases, luminescence properties, effect of calcination temperature on luminescence properties and energy transfer (ET) were investigated. The results indicated that the doping of (hbox {Pr}³⁺) and (hbox {Gd}³⁺) in all samples did not produce any new phases but caused a slight lattice expansion. The series of ((hbox {Y}_0.98-xhbox {Ce}_0.02hbox {Pr}_x)₃hbox {Al}₅hbox {O}₁₂) phosphors emit additional red light at 612 nm, and when (x=0.005), the red/yellow ratio of the emission spectrum is the largest. Compared with the ((hbox {Y}_0.975hbox {Ce}_0.02hbox {Pr}_0.005)₃hbox {Al}₅hbox {O}₁₂) phosphor, continued doping 30 at% (hbox {Gd}³⁺) in the ((hbox {Y}_0.675hbox {Ce}_0.02hbox {Pr}_0.005hbox {Gd}_0.3)₃hbox {Al}₅hbox {O}₁₂) sample makes the peak wavelength of yellow light emission shift from 533 to 561 nm. Doping (hbox {Pr}³⁺) and (hbox {Gd}³⁺) results in the decrease of integrated emission intensity, but the emission intensity and the red/yellow ratio can be increased by raising the calcination temperature. In addition, there is only the ET from (hbox {Ce}³⁺) to (hbox {Pr}³⁺) in the ((hbox {Y}_0.675hbox {Ce}_0.02hbox {Pr}_0.005hbox {Gd}_0.3)₃hbox {Al}₅hbox {O}₁₂) sample.