Synthesis and luminescence properties of a blue-emitting Sr3.5Y6.5O2(PO4)1.5SiO4(4.5) :Eu2+ phosphor.

A novel blue-emitting Sr3.5Y6.5O2(PO4)1.5SiO4(4.5) :Eu2+ phosphor was synthesized via a solid-state reaction. Powder X-ray diffraction (XRD) analysis demonstrated that the Sr3.5Y6.5O2(PO4)1.5(SiO4)4.5 host had a hexagonal crystal structure in the space group P6(3) /m and unit cell parameters a = 9.418 Å, c = 6.900 Å. The as-prepared phosphor showed a blue emission and all the main emission peaks were located at around 466 nm for different excitation wavelengths of 297, 333 and 391 nm. The temperature dependence of the photoluminescence property was investigated in the range 20-250 °C, and the emission intensity decreased to 71% of the initial value at room temperature on increasing the temperature to 150 °C. According to the classical theory of fluorescent thermal quenching, the activation energy (ΔE) for the thermal quenching luminescence of the as-prepared Sr3.45Y6.5O2(PO4)1.5(SiO4)4.5 :0.05Eu2+ phosphor was determined to be 0.20 eV.