Cr³⁺-Doped Lanthanum Gallogermanate Phosphors with Long Persistent IR Emission

Lanthanum gallogermanate co-doped with chromium (La₃Ga ₅GeO₁₄: Cr³⁺,M, where M=Li, Pb²⁺, Zn²⁺, Eu³⁺, Tm³⁺, and Dy³⁺) samples have been prepared using a solid-state chemical reaction method. The phosphor with Dy³⁺ 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.