Sunlight stimulated solar-blind ultraviolet phosphor

As a matter of experience, people always take it for granted that ambient light should be eliminated for the research and application of storage phosphors. Such an empirical viewpoint has hindered the development of storage phosphors in a lighting environment. Herein, we introduce a glow-in-the-daylight phenomenon, which is essentially photostimulated luminescence of ultraviolet phosphor upon stimulation by polychromatic daylight. As a proof of concept, imaging and spectral experiments are carried out using an x-ray-charged LuPO4:Pr3+ phosphor to demonstrate the glow performance. The charged phosphor exhibits solar-blind ultraviolet (200-280 nm) emission under sunlight, while its persistent luminescence is nearly absent in a dark environment, revealing the role of sunlight in releasing the stored energy of the phosphor. Moreover, inspired by the case of LuPO4:Pr3+, we expect to revisit other ultraviolet phosphors that do not exhibit persistent luminescence in the dark, enabling more glow-in-the-daylight materials to be developed.