New Insight into Phase Formation of M(x)Mg(2)Al(4+x)Si(5−x)O(18):Eu(2+) Solid Solution Phosphors and Its Luminescence Properties

Here we reported the phase formation of M(x)Mg(2)Al(4+x)Si(5−x)O(18):Eu(2+) (M = K, Rb) solid solution phosphors, where M(+) ions were introduced into the void channels of Mg(2)Al(4)Si(5)O(18) via Al(3+)/Si(4+) substitution to keep the charge balance. XRD results revealed that the as-prepared phosphors with different M(+) contents were iso-structural with Mg(2)Al(4)Si(5)O(18) phase. The combined analysis of the Rietveld refinement and high resolution transmission electron microscopy (HRTEM) results proved that M(+) ions were surely introduced into the intrinsic channels in Mg(2)Al(4)Si(5)O(18). The emission peaks of M(x)Mg(2)Al(4+x)Si(5−x)O(18):Eu(2+) (M = K, Rb) phosphors with various x values performed a systematic red-shift tendency, which was ascribed to the elongation of [MgO(6)] octahedra. The temperature stable photoluminescence and internal quantum efficiency (QE) of M(x)Mg(2)Al(4+x)Si(5−x)O(18):Eu(2+) (M = K, Rb) phosphors were enhanced owing to the filling of M(+) in the void channels suggesting a new insight to design the solid solution phosphors with improved photoluminescence properties.