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Facile synthesis, morphology and tunable photoluminescence properties of BaMgF <sub/>4</sub> :Ce <sup>3+</sup> /Tb <sup>3+</sup> /Eu <sup>3+</sup> phosphors
摘要： A series of BaMgF4:Ce3+/Tb3+/Eu3+ phosphors were successfully prepared via a facile hydrothermal process. X-ray diffraction (XRD), energy dispersive spectrometry (EDS), scanning electron microscopy (SEM), n-UV–UV-vis photoluminescence (PL) and fluorescence decays were employed to investigate the structure, composition, morphology, luminescence properties and energy transfer processes. The as-prepared BaMgF4 phosphors exhibit a rod-like morphology and the size of the product can be effectively regulated by changing the amount of NH4F in the original solution. Under n-UV–UV light excitation, the Ce3+, Tb3+ and Eu3+ singly-doped BaMgF4 phosphors all show good characteristic luminescence; the Ce3+–Tb3+ and Tb3+–Eu3+ co-doped BaMgF4 phosphors both show tunable emission colors from blue (green) to green (orange-red) because of the energy transfer of Ce3+ → Tb3+ and Tb3+ → Eu3+, respectively. Moreover, the efficient energy transfer from Ce3+ (Tb3+) to Tb3+ (Eu3+) ions in the co-doped samples was confirmed by investigating the excitation/emission spectra and decay lifetimes. The results indicate that the phosphors may be potentially used as single-component multi-color phosphors for white light-emitting diodes.
关键词： energy transfer,BaMgF4,white light-emitting diodes,phosphors,hydrothermal process
更新于2025-09-04 15:30:14
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Synthesis and luminescence properties of Eu3+-doped a novel double perovskite Sr2YTaO6 phosphor
摘要： A novel Sr2Y1?xTaO6:xEu3+ (x = 0.04–0.20) red-emitting phosphor was synthesized by using the conventional solid-state reaction method. The crystal structure, photoluminescence properties, thermal stability and decay lifetimes were investigated in detail. Upon near UV light excitation, this sample exhibited a strong red emission peak centered at 612?nm due to 5D0 → 7F2, which indicated that Eu3+ occupies low symmetry sites within the Sr2YTaO6 host lattice. The optimized doping concentration of Eu3+ ion is about 12?mol%. The excellent thermal stability of Sr2YTaO6:Eu3+ phosphor was tested according to the temperature dependent emission spectra. In addition, the Sr2Y1?xEuxTaO6 phosphors exhibited good color coordinate (0.6076, 0.3879) and high color purity about 84.55%. All results indicated that the Sr2Y1?xTaO6:xEu3+ phosphors can serve as an efficient red phosphor in the white light emitting diodes.
关键词： Sr2YTaO6:Eu3+,phosphor,luminescence,thermal stability,white light emitting diodes
更新于2025-09-04 15:30:14
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Design and energy transfer mechanism for single-phased Gd2MgTiO6: Bi3+, Eu3+ tunable white light-emitting phosphors
摘要： In recent years, numerous efforts have been made to develop single-phased white light-emitting phosphors for the near-UV region to solve problems of color reabsorption and ratio regulation between different phosphors. In this work, we have designed Bi3+- and Eu3+-codoped single-phased Gd2MgTiO6 phosphors to achieve tunable white light emission based on multi-luminescence center energy transfer. The structural analysis showed that all the samples were crystallized as a monoclinic double perovskite with the P21/n symmetry space group (No. 14), with HRTEM images showing clear lattice fringes between the lattice planes. The single Bi3+-doped Gd2MgTiO6 sample exhibits two obvious emission peaks at 417 and 508 nm, which correspond to a characteristic 3P1 → 1S0 transition for the Bi3+ ions under near-UV excitation due to two types of Bi3+ emission centers, with their relative emission intensity depending closely on the value of the excitation wavelength. In this case, a suitable choice of excitation wavelength can achieve tunable emission for Gd2MgTiO6: Bi3+ between blue and green. Eu3+ is codoped into Gd2MgTiO6 as a red emission component and shows sharp emission lines that correspond to the characteristic 5D0 → 7FJ (J = 1, 2, 3, and 4) transitions of Eu3+ ions. Energy transfer in Gd2MgTiO6: Bi3+, Eu3+ has been confirmed by the electric dipole–dipole (d–d) interaction from Bi3+ to Eu3+. Our experiments show that it is straightforward to create tunable white light emission by adjusting the excitation scheme and Eu3+ concentration. Moreover, a schematic for the energy transfer mechanism and simplified spectral levels based on Bi3+ and Eu3+ ions has also been established.
关键词： Eu3+,Bi3+,Gd2MgTiO6,white light-emitting phosphors,energy transfer,tunable emission,near-UV
更新于2025-09-04 15:30:14