Combustion synthesis and luminescence properties of Dy (III) activated NaBaBO_3 phosphor for solid state lighting applications

摘要

Polycrystalline samples of NaBaBO_3:Dy~(3+) were prepared by employing modified solution combustion synthesis method. The phase formation was confirmed by X-ray powder diffraction (XRD) measurements. The prepared sample was characterized by using SEM and FTIR Techniques. The photoluminescence excitation and emission spectra were measured on HITACHI F-7000 fluorescence spectrometer. Under the excitation of near- UV light, Dy~(3+) doped NaBaBO_3 presents the PLE spectra show the excitation peaks from 300 to 400 nm is due to the 4f-4f transitions of Dy~(3+). This mercury-free excitation is useful for solid state lighting and light-emitting diodes. The emission of Dy~(3+) ions upon 350 nm excitation is observed at 482 nm due to the ~4F_(9/2)→~6H_(15/2) transitions and 574 nm due to ~4F_(9/2)→~0H_(13/)2 transitions. The CIE chromaticity coordinates for NaBaBO_3:Dy~(3+) phosphors are simulated and located in the bluish-white region. The phosphor shows an excellent thermal stability on temperature quenching effects. The effect of concentration of Dy~(3+) ions on the PL intensity has also been investigated. It has been observed that the powder sample exhibits highest PL emission intensity for Dy~(3+) concentration of about 0.01 moles. The results were discussed on the relationship between the structure and the luminescence properties.