Trap Characteristic and Persistent Luminescence of ZnGa ₂ O ₄ :Cr ³⁺ Transparent Ceramics for Optical Information Storage

ABSTRACT Traps with suitable depths and appropriate distributions are indispensable for optical information storage in persistent luminescence (PersL) materials. However, ZnGa 2 O 4 : Cr 3+ fluorescent powders suffer from shallow trap depth and can hardly be regarded as candidates for storing optical information. In this study, ZnGa 2 O 4 :0.25 at% Cr 3+ PersL transparent ceramics were prepared by pressureless sintering combined with hot isostatic pressing (HIP). The ceramics exhibit in‐line transmittances of 69.1% at 0.7 µm and 82.2% at 2.5 µm. The initial afterglow intensity of the transparent ceramics is two orders of magnitude higher than that of the powders, and its duration is longer. Traps distributed in the range of 0.71–0.92 eV are suitable for optical information storage at room temperature. More oxygen vacancies and oxygen vacancy clusters were generated in the transparent ceramics due to the influence of the sintering process, which resulted in an increase in trap depth. The ceramics exhibit erasable and stable optical storage performance, with an information retention time exceeding 1 week. This study highlights the prospect of applying PersL transparent ceramics to optical information storage through trap regulation.