RESUMO
A series of barium tungstate (BaWO(4)) phosphors were synthesized by the solid state reaction method, and the systematic effect of Dy(3+)/Sr(2+) doping concentration on the structural and photoluminescence (PL) properties were investigated. X-ray diffraction studies confirm the structure of the phosphors as tetragonal with space group I4(1)/a. The PL emission spectra show two peaks in the blue and yellow regions which were tuned to produce near-white emission. The quality of the white light was checked by estimating CIE parameters. This indicates the suitability of barium-tungstate-based phosphors for near-white LED applications.
RESUMO
A series of Dy(3+)/K(+) doped calcium tungstate phosphors were synthesized by solid state reaction method. The crystal structure, surface morphology, chemical composition and photoluminescence properties of the prepared phosphors were investigated. The luminescence decay curves of doped/codoped phosphors were recorded. The X-ray diffraction analysis shows that the phosphors are of tetragonal structure. SEM studies confirm the particle size in the micro-meter (µm) range. The photoluminescence results indicate that these phosphors could be efficiently excited by the near-ultraviolet radiation which causes the emission in the blue and yellow regions. The white light was achieved by tailoring this yellow to blue ratio varying the Dy(3+)/K(+) dopant concentration. The quality of emitted white light was checked by calculating different CIE parameters of these phosphors. Decay kinetics studies confirms the life time of activator ions in micro-second (µs) range.