Blue to ultraviolet upconversion properties of Pr3+ doped Sr2MgSi2O7 phosphor.

Materials that convert visible light into ultraviolet-C (UV-C) radiation are an important class of phosphors, as UV-C has strong bactericidal activity and is widely used for disinfection and sterilization. Wide energy bandgap compounds doped with Pr3+ are capable of absorbing two blue photons and emitting one UV-C photon, making them promising candidates for next-generation UV light sources. This paper reports on Sr2MgSi2O7 phosphors doped with Pr3+ ions, which exhibit upconversion emission in the ultraviolet range (235-300 nm) under direct excitation of the 3P2 state at 444 nm. The optimal activator concentration was identified, and the dominant upconversion mechanism was determined. The spectral overlap coefficient with the germicidal effectiveness curve was found to be 0.65 - nearly twice that of standard Y2SiO5:Pr3+ - highlighting the potential of these silicates for disinfection and sterilization applications. In addition, the luminescent properties of Sr2MgSi2O7:Pr3+ crystallites in the visible and near-infrared regions were studied for the first time.