Bright persistent ceramic phosphors of Ce~(3+) -Cr~(3+) -codoped garnet able to store by blue light

摘要

We have developed bright persistent phosphors of Ce~(3+)-Cr~(3+)-doped Y_3Al_(5-x)Ga_xO_(12) (x = 2.5, 3, 3.5) ceramics with green luminescence (Ce~(3+):5d→4f) via blue-light excitation. The persistent luminance value 5 min after ceasing blue-light excitation for the Ce~(3+)-Cr~(3+)-doped Y_3Al_2Ga_3O_(12) sample is approximately 3900 times higher than that for a Ce~(3+)-doped Y_3Al_2Ga_3O_(12) sample and better than that from compact SrAl_2O_4:Eu~(2+)-Dy~(3+) powders. The results are consequences of efficient carrier trap formation and effective excitation of the interior of the translucent ceramic samples. A series of Ce~(3+)-Cr~(3+)-doped garnet materials is the best candidate for the persistent phosphor under white-light emitting diode (LED) illumination consisting of blue LEDs and visible phosphors.