Optically driven ultraviolet-C glowing from an in situ trapping–detrapping approach

In recent years, the world has witnessed rapid progress in research on ultraviolet (UV) luminescent materials, ranging from high-level anticounterfeiting, solar-blind optical tagging, to antibacterial applications. In particular, background-signal free solar-blind surveillance of ultraviolet-C (UVC) photons provides a new opportunity in both bright indoor and outdoor environments. However, ambient daylight or inevitable external photostimulation is always eliminated or underestimated for the research of persistent phosphors. Herein, an in-situ trapping-detrapping experimental procedure is employed to reveal more intrinsic properties. Total trap energy and trap modulations after photostimulation are systematically evaluated by in-situ approach. Our findings reveal the presence of optically active trapping defects with photostimulated detrapping and retrapping behavior. This work provides a fundamental advance in revealing the trap distribution and trap reshuffling during glowing-in-the-daylight event, offering new insights into manipulating traps.