Long afterglow properties of Zn2GeO4:Mn2+, Cr3+ phosphor

• Long afterglow characteristics were found in Zn2GeO4:Mn2+ phosphor by co-doping Cr3+.
• The doping of Cr3+ ions deepens the native defect VGe traps.
• The mechanism explains the phosphorescence of the Zn2GeO4:Mn2+, Cr3+ phosphor.

Zn2GeO4:Mn2+, Cr3+ phosphors were prepared by conventional solid state reaction and the photoluminescence properties were investigated. The Mn2+ activated Zn2GeO4 phosphors exhibited green emission at 533 nm due to the 4T1(4G) → 6A1(6S) transition of Mn2+ ions. With Cr3+ co-doping in Zn2GeO4 host, long afterglow characteristics were found from the same transition of Mn2+. The TL results revealed the presence of same traps in the phosphor, and the doping of Cr3+ ions deepened the VGe traps. The native defect VGe as a hole traps is responsible for the long afterglow emission in Zn2GeO4:Mn2+, Cr3+ phosphor. The possible mechanism of this phosphor has also been discussed.