Photoluminescence and persistent luminescence in Bi3+-doped Zn2GeO4 phosphors

• Zn2GeO4:Bi3+ phosphors were synthesized by solid-state reaction method.
• The photoluminescence and persistent luminescence of Zn2GeO4:Bi3+ were investigated.
• The photoluminescence and persistent luminescence mechanism of Zn2GeO4:Bi3+ was illustrated in detail.

Bi3+-doped Zn2GeO4 were prepared by the high temperature solid-state reaction method. The phase purity and crystallinity of Zn2GeO4:Bi3+ samples were characterized by X-ray diffraction (XRD). The Photoluminescence and persistent properties of Zn2GeO4:Bi3+ phosphors were investigated through the excitation spectra, the emission spectra, the persistent luminescence, the persistent decay curves and thermoluminescence spectra. Excitation into the host absorption, Zn2GeO4:Bi3+ gives a blue broadband emission; a bluish-green emission of Zn2GeO4:Bi3+ is obtained for the direct excitation of Bi3+ under 300 nm excitation. Zn2GeO4:Bi3+ shows a weak persistent luminescence after irradiation by 254 nm UV light for 3 min. The photoluminescence and persistent luminescence mechanism of Zn2GeO4:Bi3+ were discussed in detail.