Realizing highly efficient multicolor tunable emissions from Tb3+ and Eu3+ co-doped CaGd2(Wo(4))(4) phosphors via energy transfer by single ultraviolet excitation for lighting and display application's

In this paper, we reported on multicolor emission tuning in Tb3+ and Eu3+ co-doped CaGd2(WO4)(4) phosphors prepared by a traditional high-temperature solid-state reaction. Upon 380 nm ultraviolet excitation, the emission color of CaGd2(WO4)(4):Tb3+,Eu3+ phosphors can be readily tuned from green to yellow, orange and finally to pure red through varying the concentration ratio of Eu3+ and Tb3+ ions. The energy transfer mechanism from Tb3+ to Eu3+ was systematically investigated by photoluminescence spectra, luminescence decay times, and time-resolved spectra. The internal quantum efficiencies of these phosphors were measured, and their thermal stability was also studied. A prototype white light-emitting diode (LED) device was fabricated by using an ultraviolet chip combined with a blend of blue-emitting BaMgAl10O17:Eu2+ phosphors, green-emitting BaSrSiO4:Eu2+ phosphors, and red-emitting CaGd2(WO4)(4):50%Tb3+,50%Eu3+ phosphors. All the results indicate that the CaGd2(WO4)(4):Tb3+,Eu3+ has great potential application in lighting and displays.