Cr 3+ -Doped Lanthanum Gallogermanate Phosphors with Long Persistent IR Emission

Lanthanum gallogermanate co-doped with chromium (La 3 Ga 5 GeO 14 :Cr 3+ ,M, where M = Li, Pb 2+ , Zn 2+ , Eu 3+ , Tm 3+ , and Dy 3+ ) samples have been prepared using a solid-state chemical reaction method. The phosphor with Dy 3+ is observed to have a persistent IR emission for more than 8 h, which is recorded using a spectrometer. The wavelength of the major IR emission is in the range from 700 to 1100 nm. The intensity of the phosphorescence and persistent time can be modified by co-doping proper trapping centers.