Abstract
A series of color tunable phosphors NaBa3La3Si6O20:Ce3+, Tb3+ were synthesized via the high-temperature solid-state method. NaBa3La3Si6O20 crystallizes in noncentrosymmetric space group Ama2 with the cell parameters of a = 14.9226(4) Å, b = 24.5215(5) Å and c = 5.6241(2) Å by the Rietveld refinement method. The Ce3+ ions doped NaBa3La3Si6O20 phosphors have a strong absorption band from 260 to 360 nm and show near ultraviolet emission light centered at 378 nm. The Ce3+ and Tb3+ ions coactivated phosphors exhibit color tunable emission light from deep blue to green by adjusting the concentration of the Tb3+ ions. An energy transfer of Ce3+ → Tb3+ investigated by the photoluminescence properties and lifetime decay, is demonstrated to be dipole–quadrupole interaction. These results indicate the NaBa3La3Si6O20:Ce3+, Tb3+ phosphors can be considered as potential candidates for blue-green components for white light emitting diodes.
Highlights
We reported a novel silicate host phosphor, NaBa3La3Si6O20:Ce3+, Tb3+ for the excitation by a n-UV LED chip, and the crystal structure, luminescent properties and energy transfer mechanism between the Ce3+ ion and the Tb3+ ion had been thoroughly investigated
A series of novel NaBa3La3Si6O20:Ce3+, Tb3+ phosphors were prepared by solid state method
The tunable colors from deep blue to green can be realized by varying the doping concentration of the Tb3+ ions under the irradiation of 331 nm. These results demonstrate the as-prepared NaBa3La3Si6O20:Ce3+, Tb3+ samples can act as potential n-UV based white light emitting diodes (w-LEDs) phosphors
Summary
The emission band of the NaBa3La3Si6O20:0.007Ce3+ sample can be decomposed into four Gaussian components A–D peaking at 364, 380, 394 and 410 nm with the energy gaps between A and C is 2092 cm−1, that of B and D is 1926 cm−1, which are close to the theoretical value of 2000 cm−1 40,41 These results imply that there should be two kinds of Ce3+ ions, which is consistent with the previous investigation on the crystal structure that there are two kinds of different chemical environment of La3+ ions in the NaBa3La3Si6O20 host. These results indicate that the emission light color can be modulated from deep blue to green only by varying the contention of the Tb3+ ions. X is the total concentration of the Ce3+ and Tb3+ ions, where the
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