Facilitating cryogenic blue persistent luminescence in a glassy matrix

Rare-earth ion doped glass, exhibiting remarkable compositional flexibility and persistent luminescence (PersL), retains the superior attributes of traditional glass while showcasing extraordinary responsive properties, thereby expanding its applicability across diverse technological domains. However, despite numerous PersL materials displaying impressive afterglow intensity and prolonged decay duration under ambient conditions, their performance often deteriorates significantly at lower temperatures. These thermosensitive limitations hinder the ability of PersL materials to sustain their efficacy in cryogenic environments. In this study, we employed a facile microwave-assisted synthesis method to incorporate a significant quantity of uniformly distributed shallow traps (0.55-0.76 eV) into an Eu doped MgO-Al₂O₃-SiO₂ vitreous matrix, thereby enabling efficient charge storage and release across a broad temperature range (-125 °C to 200 °C). This demonstrated that the density of shallow trap distribution surpasses that of the most prevalent commercial PersL materials emitting blue light, such as Sr₂MgSi₂O₇:Eu²⁺,Dy³⁺ and CaAl₂O₄:Eu²⁺,Nd³⁺. X-ray irradiation markedly enhanced the blue PersL attributes and storage efficiency of the glass within the cryogenic temperature range (-125 °C to 0 °C). Therefore, the exceptional blue PersL properties, wide operational temperature range, and robust energy storage efficiency of the glass under X-ray excitation make it an optimal candidate for implementation in photonic data storage, ionizing radiation detection, and cryogenic safety signage applications. This study not only successfully develops a blue PersL glass matrix but also elucidates the PersL mechanism at cryogenic temperatures, providing an example for the design of other low-temperature PersL materials.