Color tuning of (K1−x,Nax)SrPO4:0.005Eu2+, yTb3+ blue-emitting phosphors via crystal field modulation and energy transfer

Nitride phosphors have drawn much interest because of their outstanding thermal and chemical stability and interesting photoluminescence properties. Currently, it remains a challenge to synthesize these phosphors through a convenient chemical route. Herein we propose a general and convenient strategy based on hydrothermal-ammonolysis reaction to successfully prepare zinc germanium nitride (ZnGeN 2 ) and Mn 2+ doped ZnGeN 2 phosphors. The crystal structure, composition, morphology, luminescence and reflectance spectra, quantum efficiency, and the temperature-dependent photoluminescence behavior were studied respectively. The phase formation and crystal structure of ZnGeN 2 were confirmed from powder X-ray diffraction and Rietveld refinement. EDX analysis confirmed the actual atomic ratios of Zn/Ge and N/Ge and suggested the presence of Ge vacancy defects in the ZnGeN 2 host, which is associated with its yellow emission at 595 nm with a FWHM of 143 nm under UV light excitation. For Mn 2+ doped ZnGeN 2 phosphor, it exhibits an intense red emission due to the 4 T 1g -6 A 1g transition of Mn 2+ ions. The unusual red emission of Mn 2+ at the tetrahedral Zn 2+ sites is attributed to the strong nephelauxetic effect and crystal field between Mn 2+ and the tetrahedrally coordinated N 3À . Moreover, the PL intensity of ZnGeN 2 :Mn 2+ phosphors can be enhanced by Mg 2+ ions partially substituting for Zn 2+ ions in a certain concentration range. The optimal Mn 2+ doping concentration in the ZnGeN 2 host is 0.4 mol%. The critical energy transfer distance of this phosphor is calculated to be about 27.99 Å and the concentration quenching mechanism is proved to be the dipole-dipole interaction. With increasing temperature, the luminescence of ZnGeN 2 :Mn 2+ phosphors gradually decreases and the FWHM of the emission band broadens from 54 nm to 75 nm. The corresponding activation energy E a was reckoned to be 0.395 eV. And the nonradiative transition probability increases with the increasing temperature, finally leading to the lifetime decrease with the increase of the temperature.

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“…72,73 Fig. S8 (ESI †) shows the CIE chromaticity of the prepared ZnGeN 2 and ZnGeN 2 :Mn 2+ phosphors.…”

Section: Diffuse Reflectance Spectra and Density Function Theory (Dftmentioning

confidence: 99%

ZnGeN₂ and ZnGeN₂:Mn²⁺ phosphors: hydrothermal-ammonolysis synthesis, structure and luminescence properties

et al. 2015

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“…However, the 35 emission from these phosphors is too blue to create a suitable white light 14 . For GdF 3 :Dy 3+ phosohors, the emission intensity of Dy 3+ at 475 nm is stronger than that at 570 nm, namely, the intensity of blue emission is greater than others emission.…”

Section: Introductionmentioning

confidence: 99%

Energy transfer and tunable multicolor emission and paramagnetic properties of GdF₃:Dy³⁺,Tb³⁺,Eu³⁺ phosphors

Guan

et al. 2016

Phys. Chem. Chem. Phys.

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A series of Dy(3+), Tb(3+), Eu(3+) singly or doubly or triply doped GdF3 phosphors were synthesized by a glutamic acid assisted one-step hydrothermal method. The samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and photoluminescence (PL) spectroscopy. The results show that the synthesized samples are all pure GdF3. The obtained samples have a peanut-like morphology with a diameter of about 270 nm and a length of about 600 nm. Under UV excitation, GdF3:Dy(3+), GdF3:Tb(3+) and GdF3:Eu(3+) samples exhibit strong blue, green and red emissions, respectively. By adjusting their relative doping concentrations in the GdF3 host, the different color hues of green and red light are obtained by co-doped Dy(3+), Tb(3+) and Tb(3+), Eu(3+) ions in the GdF3 host, respectively. Besides, there exist two energy transfer pairs in the GdF3 host: (1) Dy(3+) → Tb(3+) and (2) Tb(3+) → Eu(3+). More significantly, in the Dy(3+), Tb(3+), and Eu(3+) tri-doped GdF3 phosphors, white light can also be achieved upon excitation of UV light by adjusting the doping concentration of Eu(3+). In addition, the obtained samples also exhibit paramagnetic properties at room temperature (300 K) and low temperature (2 K). It is obvious that multifunctional Dy(3+), Tb(3+), Eu(3+) tri-doped GdF3 materials including tunable multicolors and intrinsic paramagnetic properties may have potential applications in the field of full-color displays.

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“…Up to now, many strategies have been proposed for improving the efficiency, which include the chemical modification, crystal structure and local field adjustment, introduction of codopant sensitizers and hybrid configuration, etc [10][11][12][13][14][15]. With development of plasmonic and surface enhanced spectroscopy, noble metal nanoparticles(NPs) has been considered as a new way to enhance the UC luminescence efficiency [16][17][18][19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Influence of SiO2 layer on the plasmon quenched upconversion luminescence emission of core-shell NaYF4:Yb,Er@SiO2@Ag nanocomposites

Wang

Gao

Wang

et al. 2016

Materials Research Bulletin

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β-NaYF 4 :Yb,Er@SiO 2 @Ag core-shell hybrid nanostructures are prepared and single core-shell hybrid particle is taken to investigate the influence of separation layer on the metal enhanced upconversion luminescence and corresponding mechanism. It is found that the green ( 4 S 3/2 → 4 I 15/2 ) and red ( 4 F 9/2 → 4 I 15/2 ) emissions of Er 3+ increase first and then decrease with the increase of silica shell thickness. The best enhancement is observed at the silica thickness of 12 nm. Time-resolved spectra study shows that the emission enhancement dominates when the silica thickness is 12 nm, which leads to an enhancement factor of 1.28. But the enhancement factor reduces to 0.52 when the silica shell thickness is 5 nm. Here, we define enhancement factor g(ω F ) as 0 F / ) ( I I g F   , I F and I 0 are fluorescence intensities of UCNPs with emission enhancement and without plasmon enhancement. The luminescence enhancement is owing to the enhanced emission process rather than the excitation process.

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Color tuning of (K1−x,Nax)SrPO4:0.005Eu2+, yTb3+ blue-emitting phosphors via crystal field modulation and energy transfer

Cited by 86 publications

References 27 publications

ZnGeN₂ and ZnGeN₂:Mn²⁺ phosphors: hydrothermal-ammonolysis synthesis, structure and luminescence properties

ZnGeN₂ and ZnGeN₂:Mn²⁺ phosphors: hydrothermal-ammonolysis synthesis, structure and luminescence properties

Energy transfer and tunable multicolor emission and paramagnetic properties of GdF₃:Dy³⁺,Tb³⁺,Eu³⁺ phosphors

Influence of SiO2 layer on the plasmon quenched upconversion luminescence emission of core-shell NaYF4:Yb,Er@SiO2@Ag nanocomposites

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Color tuning of (K1−x,Nax)SrPO4:0.005Eu2+, yTb3+ blue-emitting phosphors via crystal field modulation and energy transfer

Cited by 86 publications

References 27 publications

ZnGeN2 and ZnGeN2:Mn2+ phosphors: hydrothermal-ammonolysis synthesis, structure and luminescence properties

ZnGeN2 and ZnGeN2:Mn2+ phosphors: hydrothermal-ammonolysis synthesis, structure and luminescence properties

Energy transfer and tunable multicolor emission and paramagnetic properties of GdF3:Dy3+,Tb3+,Eu3+ phosphors

Influence of SiO2 layer on the plasmon quenched upconversion luminescence emission of core-shell NaYF4:Yb,Er@SiO2@Ag nanocomposites

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ZnGeN₂ and ZnGeN₂:Mn²⁺ phosphors: hydrothermal-ammonolysis synthesis, structure and luminescence properties

ZnGeN₂ and ZnGeN₂:Mn²⁺ phosphors: hydrothermal-ammonolysis synthesis, structure and luminescence properties

Energy transfer and tunable multicolor emission and paramagnetic properties of GdF₃:Dy³⁺,Tb³⁺,Eu³⁺ phosphors