Structural and luminescence properties of Y_2‐xGeMoO₈:RE_x (RE = Eu, Tb) phosphors

Abstract

Y(2-x)GeMoO8:REx (RE = Eu, Tb) phosphors were synthesized using a facile sol-gel method. The morphology and structure of the phosphors were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD); while their luminescent properties were investigated by photoluminescence (PL) spectrometry. Our results reveal that all of these Y(2-x)GeMoO8:REx (RE = Eu, Tb) phosphors adopted the tetragonal phase, belonging to Scheelite (CaWO4 ) structure. The obtained YGeMoO8:Eu phosphors exhibit a strong emission in the red light range which can be assigned to the (5)D0 → (7)F2 transition of Eu(3+) when it is excited at 459 nm. Under 392 and 489 nm excitation, the YGeMoO8:Tb phosphors present predominant green emission ((5)D4 → (7)F5) at 540 nm. The highest emission of the phosphors can be achieved by adjusting the doping concentration to be 0.25 for Eu(3+) and 0.15 for Tb(3+), respectively. The promising luminescence properties of these materials indicate that they can be potentially applied to white-light-emitting diodes.

Tunable emission, energy transfer and charge compensation in SrMoO4:Sm3+,Tb3+,Na+ phosphor

“…In Sr 0.97 MoO 4 :0.02 Tb 3+ phosphor, the PLE spectrum within the range 200–330 nm contained a broad band peaking at ~ 295 nm, which was attributed to O 2– → Mo 6+ LMCT, O 2– → Tb 3+ CT and the 4 f 8 –4 f 7 5 d 1 transition of Tb 3+ ions . Other PLE bands within the range of 330–500 nm were related to the f–f transitions of Tb 3+ ions: 7 F 6 → ( 5 D 0 , 5 L 7 , 5 L 9 , 5 G 5 , 5 G 6 and 5 D 4 ), . The PL spectrum contained four bands peaking at ~ 489, 545, 588 and 620 nm, which were attributed to the 5 D 4 → 7 F J ( J = 6, 5, 4 and 3) transitions of Tb 3+ ions .…”