Color tunable emission in Ce~(3+) and Tb~(3+) co-doped Ba_2Ln(BO_3)_2Cl (Ln = Gd and Y) phosphors for white light-emitting diodes

摘要

(Graph Presented) Ce~(3+) and Tb~(3+) co-doped Ba _2Ln(BO_3)_2Cl (Ln = Y and Gd) green emitting phosphors were prepared by solid state reaction in reductive atmosphere. The emission and excitation spectra as well as luminescence decays were investigated, showing the occurrence of efficient energy transfer from Ce ~(3+) to Tb~(3+) in this system. The phosphors exhibit both a blue emission from Ce~(3+) and a green emission from Tb~(3+) under near ultraviolet light excitation with 325-375 nm wavelength. Emission colors of phosphors could be tuned from deep blue through cyan to green by adjusting the Tb~(3+) concentrations. The energy transfer efficiency and emission intensity of Ba_2Y(BO_3)_2Cl:Ce ~(3+),Tb~(3+) precede those of Ba_2Gd(BO _3)_2Cl:Ce~(3+),Tb~(3+), and the sample Ba_2Y(BO_3)_2Cl:0.03Ce~(3+), 0.10Tb ~(3+) is the best candidate for n-UV LEDs.