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- Title
Synthesis and luminescent properties of Tb activated AWO based (A = Ca and Sr) efficient green emitting phosphors.
- Authors
Peter, Anthuvan; Shameem Banu, I.
- Abstract
Optically efficient terbium activated alkaline earth metal tungstate nano phosphors (AWO [A = Ca, Sr]) with different doping concentrations have been prepared by mechanochemically assisted solid state metathesis reaction at room temperature for the first time. The prepared phosphors were characterized by the X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscope (SEM), Fourier transform Raman (FT-Raman) spectroscopy, photoluminescence and diffuse reflectance spectroscopy measurements. The XRD and Raman spectra results showed that the prepared powders present a scheelite-type tetragonal structure. FTIR spectra exhibited a high absorption band situated at around 850 cm, which was ascribed to the W-O antisymmetric stretching vibrations into the [WO] tetrahedron groups and the SEM images reveal that the particle sizes were in the range of 20-60 nm. The excitation and the emission spectra were measured to characterize the luminescent properties of the phosphors. The excitation spectrum exhibits a charge transfer broad band along with some sharp peaks from the typical 4f-4f transitions of Tb. Under excitation of UV light, these AWO:xTb (A = Ca, Sr) phosphors showed a strong emission band centered at 545 nm (green) which corresponds to D → F transition of Tb. Analysis of the emission spectra with different Tb concentrations revealed that the optimum dopant concentration for CaWO:xTb and SrWO:xTb phosphors are about 8 and 6 mol% of Tb. The green emission intensity of the solid state meta-thesis prepared CaWO:0.08Tb and SrWO:0.06Tb phosphors are 1.5 and 1.2 times greater than that of the commercial LaPO:Ce, Tb green phosphor. All properties show that AWO:Tb (A = Ca, Sr) is a very appropriate green-emitting phosphor for fluorescent lamp applications.
- Subjects
LUMINESCENCE; TERBIUM; PHOSPHORS; FOURIER transform infrared spectroscopy; FLUORESCENT lamps; STRONTIUM; CALCIUM tungstate crystals; SCANNING electron microscopes
- Publication
Journal of Materials Science: Materials in Electronics, 2014, Vol 25, Issue 6, p2771
- ISSN
0957-4522
- Publication type
Article
- DOI
10.1007/s10854-014-1941-z