Sr4Y6(AlO4)x(SiO4)6-xOδ:Eu2+: A novel apatite structure blue-green emitting phosphor

A series of typical apatite-structure phosphors Sr4Y6(AlO4)x(SiO4)6-xO(1-x/2):0.01Eu2+ (x = 0, 1, 1.5, 1.7, 2) and Sr4Y6(AlO4)2(SiO4)4: y Eu2+ (y = 0.003, 0.005, 0.01, 0.02, 0.04, 0.05, 0.06, 0.08, 0.09) have been synthesized by a conventional high temperature solid-state reaction. Two different Eu2+ centers for Sr4Y6(AlO4)2(SiO4)4: y Eu2+ samples and the energy transfer between Eu(I) and Eu(II) have been analyzed by the photoluminescence spectra and the decay curves. The interaction mechanism has been indicated to be a dipole-dipole interaction between the Eu(I) and Eu(II). Besides, the temperature-dependent emission intensity of Sr4Y6(AlO4)2(SiO4)4: 0.06 Eu2+ was investigated, and it showed a blue-shift with the increasing temperature. The emission color could be tuned from blue to green by adjusting the ligand (XO4) or by increasing the concentration of Eu2+. All of them suggested that the typical apatite-structure phosphor Sr4Y6(AlO4)x(SiO4)6-xO(1-x/2): Eu2+ might have a potential application as a UV-LED phosphor.