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In this research, Ce31 and Tb31 doped alkaline-earth silicate Sr2MgSi2O7 phosphors have been synthesized by solid-state reaction. The results show that the Sr2
xMgSi2O7:xCe31 phosphors exhibit a violet–blue emission with excitation at 348 nm, whereas the Sr2
yMgSi2O7:yTb31 phosphor show a green emission with excitation at 243 nm. In addition, the structure of Sr2MgSi2O7 host has been analyzed by Crystalmaker program. Staggered arrangements of [SiO4] and [MgO4] units in the Sr2MgSi2O7 system underlie possible chemical tuning and phase segregation, providing a potential candidate of tunable luminescence. A red shift of wave length is clarified by crystal field theory and Van Uitert expression. The FESEM image of Sr1.99MgSi2O7:0.01Ce31 phosphors reveal that it has a proper particle size for application in WLEDs. With different Tb31 doping concentration, the CIE chromaticity coordinates Sr2MgSi2O7:Tb31 phosphors still remain a steady position. These results indicate that Sr2
xMgSi2O7:xCe31, Sr2
yMgSi2O7:yTb31 phosphors are promising phosphors for WLEDs.

I. INTRODUCTION

Since the end of the last century, the area of solid-state lighting has been a tremendous development due to a rapid advance of the technology of phosphors that is used as lighting sources on the foundation of a nitride-based lighting-emitting-diodes (LEDs) chip.1,2 Currently, LEDs are widely investigated because of their high efficiency, durability, reliability, and environmental friendliness. With more superior optical performance and easier compositions, white-lighting-emitting-diodes (WLEDs) have attracted more attention to improve properties or design novel phosphors excited by near-UV or blue light.3–6 WLEDs are considered as the next generation lighting sources to replace the traditional incandescent lamps and fluorescent lamps. Therefore, it is necessary to develop efficient and stable phosphors with high thermal quenching temperature in the visible light region under near-UV or blue excitation.7 Simultaneously, the single-composition phosphors can prevent from the drawbacks of the degradation of luminescent intensity due to the reabsorption among the phosphors, which is caused by multi-component phosphors. A controllable emission adjustment will be required to obtain white light by mixing suitable complementary color region.8–10 Rare earth ions have been widely investigated as activators to doping into host materials due to the peculiar multi-level structure with a variety types of transition.11,12 Contributing Editor: Winston V. Schoenfeld Address all correspondence to these authors. a) e-mail: [email protected] b) e-mail: [email protected] DOI: 10.1557/jmr.2016.524

Numerous 4f levels are not sensitive to local coordination environment because of shielding effect, which leads to a stable characteristic emission spectrum.13–15 In particular, 5d–4f transition of Eu21 and Ce31 are sensitive to local variation of structure, resulting in crystal field splitting to form a broad band emission.16–20 By controlling the doping concentration and preferential occ