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A novel Eu³⁺/Eu²⁺ co-doped MgSrLa₈(SiO₄)₆O₂ single-phase white light phosphor for white LEDs

Gao, Xiaoli, Liu, Haitao, Yang, Xinyu, Tian, Yiguang, Lu, Xue, Han, Liyuan
RSC advances 2017 v.7 no.3 pp. 1711-1717
X-ray diffraction, crystal structure, europium, fluorescence, oxygen, ultraviolet radiation, white light
A novel MgSrLa₈₋ₓ(SiO₄)₆O₂:xEu (MSLSO:xEu) phosphor was synthesized through a high-temperature solid-state reaction. The crystal structures, luminescent properties, fluorescence decay time, and oxygen vacancies were investigated systemically. XRD analysis shows a typical oxyapatite structure with the space group P6₃/m. Europium can enter crystal matrices simultaneously in the form of Eu³⁺ and Eu²⁺ and occupy nonequivalent crystallographic positions in a lattice, thus forming various optical centers. Under ultraviolet light excitation, the phosphors simultaneously show the blue-green emission of Eu²⁺ and the green-yellow-red emission of Eu³⁺. The optimal doping content of Eu is 7.5 mol% (x = 0.075). White light can be realized with a CIE coordinate of (0.3664, 0.3260) by adjusting the concentration of Eu. The lifetimes of Eu³⁺ and Eu²⁺ in this study are considerably longer than those in other references. The results suggest that the MSLSO:Eu²⁺/Eu³⁺ (0.075) phosphor is a promising candidate for white LEDs.