Blue Emission of Sr2-xCaxP2O7:Eu2+ for Near UV Excitation
Journal of Alloys and Compounds
Sr2−xCaxP2O7:Eu2+ (x = 0 − 2) phosphors with intense and adjustable blue emission are prepared by solid state reaction. The crystal phase evolution and correlated photoluminescence properties are studied as a function of Ca2+ content based on the experimental measurements of X-ray diffraction, photoluminescence and fluorescence decay. Our results indicate that Sr2−xCaxP2O7:Eu2+ crystallize in single α-Sr2P2O7 type phase for x ≤ 0.75. As increasing x from 0.75, α-Ca2P2O7 type phase starts to form and increase followed by reduction of α-Sr2P2O7 type phase. The single α-Ca2P2O7 type phase is obtained only at x = 2. The emission band (band I) in α-Sr2P2O7 type phase and that (band II) in α-Ca2P2O7 type phase both shift to the red on increasing x due to enhancement of crystal field strength in case of Ca2+ substitution for Sr2+. This substitution also leads to remarkably inhomogeneous broadening of band I, within which energy transfer from the high energy Eu2+ to the low energy one is observed. The superposition of band I and band II results in various distributions of intense emission band including the redshifted and more broadened ones suitable for white light generation.
Yu, Jinying, Xia Zhang, Zhendong Hao, Yongshi Luo, Xiao-Jun Wang, Jiahua Zhang.
"Blue Emission of Sr2-xCaxP2O7:Eu2+ for Near UV Excitation."
Journal of Alloys and Compounds, 515: 39-43.