Persistent luminescence of Eu/Dy-doped Sr 2 MgSi 2 O 7 glass-ceramics processed by aerodynamic levitation

Glass beads of the Sr 2 MgSi 2 O 7 stoichiometric composition and a non-stoichiometric composition with higher SiO 2 /SrO ratio doped with Eu 2 O 3 /Dy 2 O 3 were prepared through aerodynamic levitation coupled to CO 2 laser heating. The glass beads were subsequently treated at 1100 ºC to produce glass-ceramics with Sr 2 MgSi 2 O 7 : Eu 2+ , Dy 3+ as the main crystalline phase. The doped glasses exhibit red emissions; after crystallisation, the corresponding glass-ceramics emit blue light under UV excitation. The starting glass composition considerably affects the crystallisation process, resulting in Sr 2 MgSi 2 O 7 glass-ceramics with very different microstructures which, in turn, have a significant influence on the luminescence properties. The photoluminescence emission spectra of the glass-ceramics under UV light show a broadband emission (λ= 400-500 nm) with a main peak assigned to the typical Eu 2+ transition under excitation at 365 nm. Both the intensity of the emission and the persistence time significatively increase on decreasing temperature. Glass-ceramics from the non-stoichimetric glass composition co-doped with 1Eu 2 O 3 /0.5Dy 2 O 3 (mol%.) provided the longest persistence times.