Preparation of Eu ions doped Sr5(PO4)3F transparent glass ceramics and their luminescence properties

Abstract

The lack of red light components in solid-state lighting technology urgently requires the development of new efficient red-emitting bulk phosphors. Herein, we successfully prepared a kind of red-emitting glass ceramics (GCs) (λex = 392 nm, λem = 613 nm) containing Eu-doped strontium fluorophosphates (Sr5(PO4)3F:Eu) nanocrystals via a melt-quenching method in SrF2–K2CO3–P2O5–H3BO3 glass. The heat treatment temperature was found to significantly affect the grain size of the Sr5(PO4)3F:Eu nanocrystals as well as the transmittance of the prepared GCs. After heat treatment at 600 °C for 2 h, the Sr5(PO4)3F:Eu nanocrystals with grain size of about 18 nm were precipitated inside the GCs (GC600), which exhibited a high transmittance of 58–70 % in the range of 500–800 nm, with a stronger luminescence intensity than that of PG. Under excitation of 392 and 464 nm wavelengths, the CIE 1931 color coordinates of GC600 were around (0.626, 0.373) and (0.638, 0.362), respectively, both falling in red region. The present Sr5(PO4)3F:Eu GCs are promising as red phosphors for UV-pumped white-light LEDs.