Gel-combustion assisted synthesis of eulytite-type Sr3Y(PO4)3 as a single host for narrow-band Eu3+ and broad-band Eu2+ emissions.

A series of eulytite-type Sr 3 Y 1- x (PO 4 ) 3 : x Eu 3+ ( x = 0–0.13) and Sr 3- y Y(PO 4 ) 3 : y Eu 2+ ( y = 0–0.10) phosphors were successfully synthesized via gel-combustion and subsequent calcination in O 2 and Ar/H 2 atmospheres at 1250 °C, respectively. Detailed crystal structure analysis via Rietveld refinement showed that the phosphors were crystallized in the cubic system (space group I -43 d , No. 220), in which the Eu 3+ and Eu 2+ activators reside at the Y 3+ and Sr 2+ sites, respectively. The trivalent Eu 3+ ions (CN = 6) exhibited typical narrow-band luminescence via intra-4 f 6 transitions, with the red emission at ~ 615 nm being dominant ( 5 D 0 → 7 F 2 transition, FWHM = 15.9 ± 0.2 nm). The divalent Eu 2+ ions (CN = 6 and 9) showed broad-band luminescence ranging from light-blue to blue via 4 f 6 5 d 1 → 4 f 7 transitions (FWHM = 115 ± 2 nm). The optimal Eu 3+ and Eu 2+ concentrations were determined to be 10 at% ( x = 0.10) and 7 at% ( y = 0.07), respectively, and the mechanisms of concentration quenching were discussed. The excitation/emission properties, fluorescence decay kinetics, CIE chromaticity, and particularly the rarely addressed thermal stability of the phosphors were investigated in detail. [ABSTRACT FROM AUTHOR]