Rechargeable and sunlight-activated Sr3Y2Ge3O12:Bi3+ UV–Visible-NIR persistent luminescence material for night-vision signage and optical information storage

Persistent luminescence (PersL) materials that can be excited by natural sunlight are in great demand to reduce energy consumption, but the design and development of efficient sunlight-activated PersL phosphor remains a daunting challenge so far. Herein, we report the development of a new kind of sunlight-activated PersL material based on Bi3+-doped Sr3Y2Ge3O12 (SYGO) phosphor, which exhibits an intense UV–Visible-NIR PersL and possesses a super-long PersL longer than 60 h. This newly developed PersL material can be effectively and repeatedly activated by sunlight radiation in all kinds of weather conditions because of its high response to both direct sunlight and diffuse solar radiation. Owing to the existence of stabilized deep traps with suitable depths, SYGO:Bi3+ also shows excellent photostimulated luminescence (PSL) properties. A series of excitation-time-dependent TL experiments, PL and PersL spectra were systematically studied to reveal the trapping and de-trapping processes of this material. Furthermore, by utilizing the unique PersL and PSL properties, we demonstrate the applications of SYGO:Bi3+ for night-vision signage and optical information storage. Our achievement in the case of Bi3+-doped SYGO phosphor is expected to promote the future development of more excellent sunlight-activated and photostimulated PersL materials towards versatile practical applications.