Ca8MgSm1-x(PO4)7:xEu3+, promising red phosphors for WLED application

JOURNAL OF ALLOYS AND COMPOUNDS

卷:776

Article

Deyneko, Dina, V¹  Nikiforov, Ivan, V¹  Lazoryak, Bogdan, I¹  Spassky, Dmitry A.²  Leonidov, Ivan I.³  Stefanovich, Sergey Yu¹  Petrova, Dania A.^1,4  Aksenov, Sergey M.^5,6  Burns, Peter C.^6,7 

[1] Lomonosov Moscow State Univ, Dept Chem, Moscow 119991, Russia

[2] Lomonosov Moscow State Univ, Skobeltsyn Inst Nucl Phys, Moscow 119991, Russia

[3] UB RAS, Inst Solid State Chem, Ekaterinburg 620990, Russia

[4] Gubkin Univ Oil & Gas, Moscow 119991, Russia

[5] RAS, Nesmeyanov Inst Organoelement Cpds, Moscow 119991, Russia

[6] Univ Notre Dame, Dept Civil & Environm Engn & Earth Sci, Notre Dame, IN 46556 USA

[7] Univ Notre Dame, Dept Chem & Biochem, Notre Dame, IN 46556 USA

关键词: Red phosphors;    Whitlockite-type structure;    WLED;    Sm3+;    Eu3+;   

DOI  :  10.1016/j.jallcom.2018.10.317

来源: Elsevier

【 摘 要 】

Novel red emitting phosphors Ca8MgSm1-x(PO4)(7):xEu(3+) with whitlockite-type structure were prepared by a high temperature solid-state reaction in air. Powder X-ray diffraction (PXRD), photoluminescence spectra, and fluorescence decay were used to characterize the structure and luminescence properties. All samples were found to have the expected rhombohedral structure with R (3) over barc space group. The non-polar space group is also confirmed by a photoluminescence study. This space group allows forbidden transitions for Eu3+. The presence of only one Shtark component in D-5(0)-F-7(0) confirms the presence of only one non-equivalent site containing Eu3+ ions. The high intensity of the transition ratio D-5(0)-F-7(2)/D-5(0)-F-7(1) establishes the strongly disordered environment of the Eu3+ ions. Thus, M1-M3 sites in the host matrix are occupied by Ca2+, Sm3+, and Eu3+ ions, whereas M5 is fully occupied by Mg2+. The optimal concentration was found with x = 0.75 in Ca8MgSm1-x(PO4)(7):XEu3+ phosphors. The emitting of Sm3+ was depressed due to the high intensity of Eu3+ luminescence; however, the contribution of Sm3+ is manifested in the energy transfer process and shift of CIE coordinates. Furthermore, the CIE chromaticity coordinate of as-prepared Ca8MgSm0.25(PO4)(7):0.75Eu(3+) (x = 0.650; y = 0.345) is close to the standard red-emitting point (x = 0.67, y=0.33). The experimental data indicate that Ca8MgSm1-x(PO4)(7):XEu3+ upon excitation by near-UV radiation is a promising red phosphor for white-light-emitting diodes. (C) 2018 Elsevier B.V. All rights reserved.

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