White light generation in Eu- and Mn-codoped Ca(7)Mg(2)P(6)O(24) phosphor for white light-emitting diodes

Polycrystalline Ca(7)Mg(2)P(6)O(24):Eu(2+),Mn(2+) phosphors were prepared by a solid-state reaction under a weak reductive atmosphere. The phosphors have been characterized by X-ray diffraction and fluorescence measurements. The results show that the obtained phosphors are of single-phase rhombohedral Ca(7)Mg(2)P(6)O(24). Upon excitation of 355nm ultraviolet (UV) light, two intense broad bands have clearly been observed due to the allowed 5d-4f transition of Eu(2+) and the forbidden (4)T(1)-(6)A(1) transition of Mn(2+), respectively. A white light has been obtained from Ca(7)Mg(2)P(6)O(24):0.035Eu(2+),0.5Mn(2+) phosphor with CIE chromaticity coordinates of (x=0.32, y=0.29) and color temperature of 6175K. These results suggest that Ca(7)Mg(2)P(6)O(24):Eu(2+),Mn(2+) phosphors could be a promising candidate for UV-converting white light-emitting diodes (LEDs).