Synthesis and luminescence properties of glass ceramics containing MSiO3:Eu2+ (M=Ca, Sr, Ba) phosphors for white LED

Abstract Eu 2+ doped silicate glasses were prepared of the system 52SiO 2 –48MO: x Eu 2+ (in molar ratio, M=Ca, Sr, Ba; x =1, 3, 5, 7, 9) by a high temperature melt-quenching method in a reducing atmosphere. Glass ceramics containing MSiO 3 :Eu 2+ (M=Ca, Sr, Ba) nano-phosphors were obtained after the heat treatment of the glass samples. The excitation, emission spectra and lifetime decay curves of 4f 6 5d 1 →4f 7 of Eu 2+ were measured and interpreted with respect to their crystal structures and multi-site occupations of divalent europium in the hosts. Their excitation bands mainly extend from 450 to 250 nm, which is adaptable to the main emission region of the UV LED chip. With UV light excitation, the Eu 2+ emission in CaSiO 3 , SrSiO 3 and BaSiO 3 shows blue, green and yellow colors centered at 440, 505 and 555 nm, respectively. The critical Eu 2+ concentration was studied and determined to be x =5 for both CaSiO 3 and SrSiO 3 and x =7 for BaSiO 3 phosphors. The results show that the Eu 2+ doped glass ceramic phosphors containing MSiO 3 (M=Ca, Sr, Ba) nano-crystals can be used as potential matrix materials for a high power white LED pumped by the UV LED chip.