Article

Color point tuning of Y3Al5O12:Ce3+ phosphor via Mn2+-Si4+ incorporation for white light generation

Journal of Materials Chemistry (Impact Factor: 6.63). 07/2012; DOI: 10.1039/C2JM32233A

ABSTRACT In this paper, the color point tuning of Y3Al5O12:Ce3+ phosphor has been realized by the incorporation of Mn2+-Si4+. The Mn2+ ions occupy the dodecahedral crystallographic Y3+ site, while the Si4+ ions substitute the tetrahedral Al3+ crystallographic site in the obtained powder. Under the 450 nm excitation, the YAG:Ce3+, Mn2+, Si4+ samples exhibit the typical yellowish-green emission band of the Ce3+ ions, as well as an orange emission band of the Mn2+ ions. Furthermore, the intensity ratio of the orange/yellowish-green band can be enhanced through the increase of Mn2+-Si4+ content. The intense orange emission band of the Mn2+ ions is attributed to the effective energy transfer from the Ce3+ to Mn2+ ions, which has been justified through the luminescence spectra and the fluorescence decay dynamics. The related mechanism was demonstrated to be the electric dipole-quadrupole interaction based on the Inokuti-Hirayama theoretical model, and critical distance is calculated to be 8.57A by the spectral overla

Full-text

Available from: Yongchao Jia, Jun 08, 2015
1 Follower
 · 
272 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: We report the surface modification of orange-red-emitting hexagonal and monoclinic polymorphs of BiPO4:Eu3+ with oleic acid (OA) for white light generation. The surface-modified hexagonal phase emits white light under near-UV excitation (350–395 nm) through the mixing of broad blue emission from OA and orange-red emission from Eu3+, whereas the same was not observed with the monoclinic phase. The variation in OA emission upon anchoring over the surface of hexagonal BiPO4:Eu3+ resulted in white light generation. Such variation in the interaction of OA with surfaces of BiPO4 polymorphs and surface induced midgap states was established through first-principles calculations that revealed the strong interaction of OA with hexagonal phase. The deduced density of states corroborates the experimental findings on the polymorph-dependent PL properties of OA-modified hexagonal and monoclinic BiPO4:Eu3+.
    The Journal of Physical Chemistry C 08/2014; 118(33):19308. DOI:10.1021/jp505454n · 4.84 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Cation substitution is a valuable approach to tune the crystal field splitting of garnet phosphor and hence enhances the red shift of the Ce3+ emission. A novel aluminate silicate garnet phosphor Mg2Y2Al2Si2O12:Ce3+ is designed with the aim of creating a large distortion of the dodecahedron and an external pressure from the large octahedron through the combination of the substitution of both dodecahedral Y3+ and octahedral Al3+ sites with Mg2+. The garnet structure and elemental composition of this phosphor were confirmed by XRD, SEM and TEM. The particular coordination environment of each element of the phosphor was illustrated by XPS and Rietveld refinement. Mg2Y1.94Al2Si2O12:0.06Ce(3+) exhibits a strong and broad yellow-orange emission band with a CIE coordinate of (x = 0.519, y = 0.472) and shifts to the red side of 57 nm, compared with the commercial phosphor YAG: Ce3+. This red-shift could be mainly ascribed to the distortion and shrinking of the dodecahedron, and subsequently, the larger crystal field splitting of the Ce3+ 5d levels. A white LED was fabricated and showed a high colour rending index of up to 84. These results reveal that Ce3+-doped Mg2Y2Al2Si2O12 phosphor is a promising blue light converted yellow-orange light emitting phosphor for white LED.
    RSC Advances 01/2014; 5(13):9489-9496. DOI:10.1039/C4RA14425B · 3.71 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: tilizing Mn2+ and Tb3+ ions as energy-transfer acceptors, we report a series of emission color-tunable Ca2GdZr2(AlO4)3:Ce3+,Mn2+,Tb3+ aluminate garnets. Incorporating Mn2+ and Tb3+ into Ca2GdZr2(AlO4)3:Ce3+ phosphor generates an orange emission band peaking at 572 nm and a green line peaking at 550 nm. The energy transfer from Ce3+ to Mn2+ and Ce3+ to Tb3+ ions are deduced from the spectral overlap between Ce3+ emission and Mn2+/Tb3+ excitation spectra. Fluorescence decay patterns are studied as a function of Mn2+ and Tb3+ concentrations. The calculated values based on the luminescence dynamical process indicates that the intensity ratios of orange to green band as a function of Mn2+ concentrations are in good agreement with that obtained directly from emission spectra. Commission on illumination value of color tumble emission as well as luminescence external quantum yield (20.4−48.9%) can be tuned by precisely controlling the content of Ce3+, Mn2+, and Tb3+. The energy transfer significantly enables the achievement of a broad emission spectrum covering an orange spectral region. It is suitable for a near-UV light-emitting diode (LED) excitation.
    01/2015; DOI:10.1039/C4TC02652G