Tunable luminescence and energy transfer of Ce3+/Eu2+/Mn2+-tridoped Sr8MgLa(PO4)7 phosphor for white light LEDs

A series of Ce3+/Eu2+/Mn2+-tridoped Sr8MgLa(PO4)(7) phosphors were synthesized by a solid state reaction. The crystal structure and luminescence properties were characterized by X-ray diffraction (XRD), photoluminescence emission spectroscopy (PL), and X-ray photoelectron spectroscopy (XPS). Effective energy transfer occurs from Ce3+ to Eu2+ and from Ce3+/Eu2+ to Mn2+ in Sr8MgLa(PO4)(7) host. Under near ultraviolet (UV) excitation, Sr8MgLa(PO4)(7):Eu2+,Mn2+ phosphor exhibits the yellow-green emission of the Eu2+ ions and the red emission of the Mn2+ ions and the emission color can be tuned from yellow egreen to orange with variation of the Mn2+ content. Co-doping Ce3+ ions is proved to be an effective approach to enhance both the emissions of Eu2+ and Mn2+ ions. A cascade model of energy transfer Ce3+ -> Eu2+ -> Mn2+ was put forward to explain the ET process in SMLP:Ce3+,Eu2+,Mn2+ system. Additionally, an increase in the number of luminescent centers (Eu2+) on Ce doping may be other causes of the enhanced Eu2+ luminescence. The developed Sr8MgLa(PO4)(7):Ce3+,Eu2+,Mn2+ phosphors could have potential applications in near UV-pumped white LEDs. (C) 2015 Elsevier B.V. All rights reserved.