Sunlight Activated Long-Lasting Luminescence from Ba₅Si₈O₂₁: Eu²⁺,Dy³⁺ Phosphor

Visible-light persistent phosphors are commonly used as self-sustained night vision and fluorescence labeling materials. From the inspiration of the structure of six-membered rings plane in Ba4(Si3O8)2, a similar structure of Ba5Si8O21 is expected that could exhibit more excellent phosphorescence property. In this Article, we report a novel visible long-lasting luminescence phosphor of Eu(2+)/Dy(3+) codoped Ba5Si8O21 for the first time. Ba5Si8O21:Eu(2+),Dy(3+) phosphor could be activated effectively by sunlight or even in severe weather conditions, which is mainly attributed to the broad excitation spectrum (200-455 nm) and highly responds to UV-A and violet-light in the solar spectrum. After activation, Ba5Si8O21:Eu(2+),Dy(3+) emits intense emission at 380-680 nm with persistent phosphorescence beyond 16 h. Moreover, it exhibits excellent and stable phosphorescence even in water, indicating that Ba5Si8O21:Eu(2+),Dy(3+) will be a all-weather material that can be effectively and repeatedly charged by natural daylight in all kinds of open-air environments. Furthermore, the quantum tunneling behavior was illustrated in the afterglow mechanism.