Translucent and persistent luminescent SrAl2O4:Eu2+Dy3+ ceramics

Ceramics that exhibit persistent luminescence are usually opaque, which limits their utility. In this work, a laser-sintering technique is employed to produce persistent luminescent SrAl2O4:Eu2+Dy3+ ceramics that has enhanced translucency in the visible spectral range. In this technique, a CO2 laser was used as the main heating source for sintering with no atmosphere control employed. The ceramics sintered at a power density of 3.1 W/mm2 yielded homogeneous grain size distributions and transmittance up to 40% in the range of 600–800 nm. Upon sintering in air, the ceramics exhibited the characteristic green emission from the Eu2+ ion, corresponding to the 5d→4f transition (514 nm) and a weak emission from the Eu3+ ion at 614 nm, corresponding to the 5D0→7F2 transition. The valence of europium ions was further studied by the X-ray absorption spectroscopy in the XANES region and those details are reported herein.