Near infrared persistent luminescence of transparent Zn-Ga-Ge-O:Cr3+ glass ceramic for optical information storage

Cr 3+ -doped near-infrared (NIR) afterglow phosphors have received wide recognition in the optical storage field because of the high signal-to-noise ratio and broad excitation spectra. In this article, the high-temperature TL intensity of ZnGa 2 O 4 :Cr 3+ afterglow glass ceramic (ZGO:Cr 3+ GC) was enhanced via partial hetero-valence substitution of Ge for Ga, demonstrating the tunability of the trapped electron levels in ZGO:Cr 3+ GC. The persistent luminescence phosphor ZGO:Cr 3+ GC exhibits a zero-phonon lines emission peaking at 698 nm, attributing to the 2 E→ 4 A 2g transition of Cr 3+ ions. Moreover, the trap levels in Zn-Ga-Ge-O:Cr 3+ glass ceramic (ZGGO:Cr 3+ GC) are deeper than those of the Ge-free one and the captured electrons in deeper levels cannot be released only by the ambient thermal energy, thus the optical storage capacity of ZGGO:Cr 3+ GC is much larger. By means of an additional 980 nm laser photostimulation, an intense NIR emission could be obtained. In consequence, ZGGO:Cr 3+ GC has a promising application prospect in optical information storage field.