Tunable white light emission from single-phased Li2 SrSiO4 :Dy(3+) phosphors by co-doping with Eu(3+)

A series of single-phase full-color emitting Li2 Sr1-x-y SiO4 :xDy(3+) ,yEu(3+) phosphors were synthesized by solid-state reaction and characterized by X-ray diffraction and photoluminescence analyses. The samples showed emission peaks at 488 nm (blue), 572 nm (yellow), 592 nm (orange) and 617 nm (red) under 393 nm excitation. The photoluminescence excitation spectra, comprising the Eu-O charge transfer band and 4f-4f transition bands of Dy(3+) and Eu(3+) , range from 200 to 500 nm. The Commission Internationale de I'Eclairage chromaticity coordinates for Li2 Sr0.98-x SiO4 :0.02Dy(3+) ,xEu(3+) phosphors were simulated. By manipulating Eu(3+) and Dy(3+) concentrations, the color points of Li2 Sr1-x-y SiO4 :xDy(3+) ,yEu(3+) were tuned from the greenish-white region to white light and eventually to reddish-white region, demonstrating that a tunable white light can be obtained by Li2 Sr1-x-y SiO4 :xDy(3+) ,yEu(3+) phosphors. Li2 Sr0.98-x SiO4 :0.02Dy(3+) , xEu(3+) can serve as a white-light-emitting phosphor for phosphor-converted light-emitting diode.