Fabrication of Eu:SrAl2O4-based glass ceramics using Frozen sorbet method

The Frozen sorbet (FS) method is applied to the SrO–Al2O3–B2O3 system in order to fabricate glass ceramics consisting of Eu2+,Dy3+-doped SrAl2O4 phosphors, and their luminescent properties are examined. Through the quenching of melts (e.g., 55SrO–27Al2O3–18B2O3 with Eu2O3 and Dy2O3), composites (glass ceramics) consisting of the glass phase and SrAl2O4 crystals with a diameter of ∼40 µm are fabricated. It is found that SrAl2O4 crystals in the glass ceramics show excellent long persistent phosphorescent properties and improved excitation efficiency at ∼460 nm in the PL excitation spectra compared with SrAl2O4 phosphors prepared using a conventional solid state reaction. It is suggested that the Al3+-sites in SrAl2O4 crystals are partially substituted by B3+-ions. The present study proposes that the Frozen sorbet method can be a useful technique for the design of new SrAl2O4-based phosphor composites which can be used under white light emitting diode (LED) excitation (∼460 nm).