Correlation of Structure, Tunable Colors, and Lifetimes of (Sr, Ca, Ba)Al(2)O(4):Eu(2+), Dy(3+) Phosphors

(Sr, Ca, Ba)Al(2)O(4):Eu(2+), Dy(3+) phosphors were prepared via a high temperature solid-state reaction method. The correlation of phase structure, optical properties and lifetimes of the phosphors are investigated in this work. For the (Sr, Ca)Al(2)O(4):Eu(2+), Dy(3+) phosphors, the different phase formation from monoclinic SrAl(2)O(4) phase to hexagonal SrAl(2)O(4) phase to monoclinic CaAl(2)O(4) phase was observed when the Ca content increased. The emission color of SrAl(2)O(4):Eu(2+), Dy(3+) phosphors varied from green to blue. For the (Sr, Ba)Al(2)O(4):Eu(2+), Dy(3+) phosphors, different phase formation from the monoclinic SrAl(2)O(4) phase to the hexagonal BaAl(2)O(4) phase was observed, along with a shift of emission wavelength from 520 nm to 500 nm. More interestingly, the decay time of SrAl(2)O(4):Eu(2+), Dy(3+) changed due to the different phase formations. Lifetime can be dramatically shortened by the substitution of Sr(2+) with Ba(2+) cations, resulting in improving the performance of the alternating current light emitting diode (AC-LED). Finally, intense LEDs are successfully obtained by combining these phosphors with Ga(In)N near UV chips.