Novel Ca8Mg3AlGaSi7O28:Eu2+,Ce3+ phosphor with blue emitting and persistent green luminescence for emergency lighting

Abstract

A special optical phenomenon called persistent luminescence, or long afterglow, occurs when light emission lasts for hours or even days after stimulation is turned off. Persistent luminescent materials have attracted significant research attention and have found extensive application in a variety of fields. These include safety signage, security ink, and night-vision monitoring. Nevertheless, the majority of these compounds only glow in one color and need to be excited in the UV region of the spectrum; these characteristics restrict their applicability to particular uses. Hence, it is significant to develop long afterglow luminescent materials that are color-tunable and chargeable by blue light. In this study, a persistent luminescence material, Ca₈Mg₃AlGaSi₇O₂₈:Eu²⁺,Ce³⁺, with blue photoluminescence and blue-light-excited yellowish-green persistent luminescence is investigated. Ca₈Mg₃AlGaSi₇O₂₈:Eu²⁺ exhibits a broadband bright yellowish-green emission centered at 530 nm, which is attributed to the 4f⁷ → 4f⁶5d¹ electron transition of Eu²⁺ ions. Moreover, color-tunable emission from bright yellowish-green to blue with yellowish-green persistent luminescence is achieved by adjusting the Ce³⁺ concentration. Owing to the integration of photo-stimulated luminescence, persistent luminescence and color-tunability, this integrated luminescent Ca₈Mg₃AlGaSi₇O₂₈:Eu²⁺,Ce³⁺ phosphor has potential applications in emergency lighting, optical data storage and anti-counterfeiting.