Synthesis of some silicates doped with eu3 and estimation of luminescence properties for red phosphors

Abstract

The Substance which exhibits the phenomenon of Luminescence is called Phosphor. The phosphor materials are play important role in solid state lighting devices to emit colors by exciting with suitable wavelengths. For that the phosphors should satisfy the criteria like high luminescent intensity, Least thermal quenching, Good color purity, regular morphology and low cost. Now a days for solid state lighting inorganic phosphors based silicate, aluminate and borate has great attention because of its high thermal, chemical and structural properties. Europium doped yttrium silicate phosphor material has been prepared using a combustion method with two step process for large scale production. For this material, the emission characteristics, crystallite size and morphology have been analyzed through PL, XRD and FE-SEM respectively. The prepared material belongs to the structure of and#945;-Y2Si2O7 (JCPDS card: 38-0223) which is confirmed by XRD analysis and its average crystallite size found to be 37nm. From PL analysis, the excitation peaks are observed at 260, 321, 363, 379, 384, 396, 412 and 416 nm. The broad band is centered at 260 nm is known as a charge transfer band (CTB). Moreover, the emission peaks are observed at 579, 587, 590, 598, 612, 615, 620 and 699 nm. From the ratio between the intensity of magnetic and electric dipole transition (I587nm and I620nm), the preferred site of Eu3+ has been discussed in this paper. The relation between Eu3+ concentration and PL intensity is also discussed. Eu3+ activated NaYSiO4, Na(1-x)YSiO4 and NaY(1-x)SiO4 high intense red emitting phosphors were prepared by a combustion method with two step process. The structure, luminescent properties and vibrational analysis of these powder samples were investigated by X-ray diffraction, newline