Color-tunable photoluminescence and persistent luminescence in a single LiYGeO4:Tb3+ phosphor

Persistent luminescence (PerL) phosphors have been widely applied in many advanced applications in the field of emergency lighting, safety signage, and ornaments. Recently, the PerL phosphors based on germanates have attracted great attention owing to their excellent PerL performance. However, the design and development of excellent germanates-based PerL materials with full spectral emissions remain challenging due to the lack of color-tunable PerL, especially in the blue and green regions (400-600 nm). Herein, we develop a new type of Tb3+-activated LiYGeO4 PerL phosphor with real-time adjusting the photoluminescence (PL) and PerL color, which can be effectively excited by a 254 UV light. Both blue and green PerL are realized simultaneously in a single phosphor. When LiYGeO4:Tb3+ doped with lower concentrations of Tb3+ ions, phosphors emit blue PL and PerL. With increasing Tb3+ concentration, the PL and PerL colors of LiYGeO4:Tb3+ PerL phosphor are gradually regulated from blue to green. Besides, LiYGeO4:Tb3+ exhibits temperature-dependent luminescence property, whose PL and PerL colors can also be successively widely tuned by various temperature. This stable and tunable color in real-time PL and PerL property promote the as-designed LiYGeO4:Tb3+ phosphor to have potential applications in advanced anti-counterfeiting and display devices.