A new persistent luminescent composite for tracing toxic air particulate matter

Air pollution is a major health issue, notably due to the presence of potentially toxic particulate matter with a diameter of lower than or equal to 2.5 µm, named 'PM2.5.' There is, however, few precise knowledge on the sources, fate and toxicity of particulate matter, notably because there is a lack of method to trace particulate matter in the long term and over large distances. Therefore, we prepared here a novel persistent luminescent tracer composite by incorporating Zn₃Ga₂GeO₈:1%Cr (ZGGO:Cr) persistent luminescence phosphor into PM2.5 precursor followed by freeze drying. Due to a –C=O– chemical bond between PM2.5 and ZGGO:Cr, the obtained composite is well combined and can emit long-lasting persistent emission, of more than 100 min, peaking at 696 nm, following excitation by a 274 nm light. Furthermore, the ZGGO:Cr/PM2.5 composite is performed for simulated ~ 1-cm-thick tissue imaging. The new luminescent PM2.5 composite can be used for environment inspection, imaging, therapy and other complex applications.