Eu Ions Doped Transparent Glass Ceramics Containing Sr₅(PO₄)₃F Crystals for UV LEDs

New types of red fluorescent conversion materials promote the application of solid-state lighting technology. In this study, we successfully prepared Eu-doped strontium fluorophosphate (Sr₅(PO₄)₃F:Eu) red-emitting transparent glass ceramics (GCs) with SrF₂-Zn₂SO₄-P₂O₅-H₃BO₃ glass matrix using a melt-quenching method. GCs were obtained by heating precursor glass (PG). After the obtained Sr₅(PO₄)₃F:Eu GCs (GC120) were thermally treated at 610°C for 120 min, they exhibited a transmittance of 48% in the range of 500-800 nm, achieving a stronger luminescence intensity and longer fluorescence lifetime than PG. The CIE 1931 color coordinates of GC120 were in the red region (0.643, 0.357), and its photoluminescence quantum yield (PLQY) was 37.9%. Finally, using GC120 as the red phosphors, white-light LEDs with a correlated color temperature of 5356 K and R_a = 84.6 (color render index) were obtained. Hence, Sr₅(PO₄)₃F:Eu GCs are promising red phosphors for white-light LEDs under UV-LED excitation.