Long persistent luminescence and traps distribution of Tb3+ doped calcium gallium germanate

A new type of long persistent green luminescent phosphor Ca2Ga2GeO7: Tb3+ was prepared by high temperature solid-state reaction technique. In this paper, the crystal structure, luminescence properties and decay curves of phosphors were mainly studied. The long persistent luminescence (LPL) properties of these phosphors were characterized by LPL spectra, LPL decay curves and thermoluminescence (TL) spectra. When the ultraviolet (UV) light source was turned off, Ca2Ga2GeO7: Tb3+ phosphor exhibit typical LPL behavior for approximately 1.2 h. The green-emitting LPL was originated form the typical 5D4→7F5 transition of Tb3+ ions, and the green LPL is similar to PL. Based on the experimental results, the LPL mechanism and traps distribution of the Ca2Ga2GeO7: Tb3+ was described via TL analysis in detail.