Synthesis and photoluminescence properties of Eu2+-activated Sr9In1−yLuy(PO4)7 phosphors
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In this work, two series of phosphors of Sr9−xIn(PO4)7:xEu2+ and Sr8.97In1−yLuy(PO4)7:0.03Eu2+ with β-Ca3(PO4)2-type structure are prepared via a high temperature solid-state reaction. The XRD, photoluminescence, photoluminescence excitation spectra and decay times are investigated in detail. Upon excitation at 365 nm, the Sr9−xIn(PO4)7:xEu2+ phosphors show a obvious band centered at 410 nm and a little hump peaked at 630 nm ascribed to the 4f65d1–4f7 transitions of Eu2+ in different crystallographic sites. The excitation spectra show a broad band in the 250–500 nm, which is well-matched with the NUV LED chip. For the Sr8.97In1−yLuy(PO4)7:0.03Eu2+ phosphors, the another emission band centered at 520 nm emerged with the substitution of Lu3+ for In3+ on the basis of Sr9In(PO4)7:Eu2+ phosphor under the 365 nm excitation, which indicates that the presence of different Eu2+ luminescence centers. And emitting-color can be tuned from bluish-violet to white and yellow-green by varying the ratio of Lu3+ and In3+. Our results indicate these phosphors can be as an attractive candidate for the application of white LEDs by ions substitution to obtain white light and tunable luminescent.
This work was financially supported by the Natural Science Foundation of Shanxi Province (201601d011030), Program for the Top Young Academic Leaders of Higher Learning Institutions of Shanxi, and school fund of Taiyuan University of Technology (1205-04020102).