Preparation and Optical Properties of Near Infrared Persistent Luminescence Material of ZnGa₂O₄：Cr³⁺

In this paper, the near infrared persistent luminescent material ZnGa₂O₄：Cr³⁺ is prepared by a high temperature solid state method and the photoluminescence, long persistent photoluminescence, photostimulated luminescence and thermoluminescence properties of ZnGa₂O₄：Cr³⁺ are studied in details. The persistent luminescence excitation spectra reveal that the persistent luminescence of ZnGa₂O₄：Cr³⁺ comes from the charge transfer transition from O^2-to Ga³⁺ instead of the intrinsic transition of Cr³⁺. The investigation in photo-stimulated persistent luminescence indicates that the sample can emit bright persistent luminescence again under infrared light excitation after the UV light excited persistent luminescence decays completely. The result shows that the UV light written information in ZnGa₂O₄：Cr³⁺can be read by infrared light. Moreover, in accordance with the result, the recombination luminescence model of conduction electrons is employed to elaborate the luminescence mechanism of the sample.