Short wavelength persistent luminescence in the ultraviolet A region from a novel phosphor

Abstract

Ultraviolet-A (UVA) persistent luminescent materials (PLMs) have recently attracted growing attention for their potential applications to activate photosensitizers in photodynamic therapy and continuous sterilization. However, the emission spectra of currently reported UVA PLMs are chiefly located in 350–400 nm, and UVA PLMs with shorter wavelengths below 350 nm are still lacking. Here, a series of novel short wavelength UVA PLMs, Mg4Y2-xLuxGe3O13:Bi3+, are synthesized. By adjusting x, tuning of the PersL emission peak from 340 to 330 nm is realized. Among these PLMs, Mg4Y1.2Lu0.8Ge3O13:Bi3+ has the best PersL intensity performance. To further improve the PersL performance, it was found that Li+-doping significantly enhances its PersL intensity with a decay time lasting more than 100 h. Moreover, Mg4Y1.2Lu0.8Ge3O13:Bi3+,Li+ (MYLGO) can be rejuvenated by short-time photostimulation with a red LED or NIR laser illumination after the long-term decay. This work enriches the short wavelength UVA PLMs, and MYLGO is expected to have potential applications in the fields of medical therapy and continuous sterilization.