RbBaScSi3O9: A suitable host for generating blue emitting phosphor doped with Ce3+ and enhanced cyan-green emitting phosphor co-doped with Eu2+ and Dy3+

Abstract

Inorganic phosphors based on RbBaScSi3O9 (RBS), a chemically and thermally stable host doped with Ce3+; Eu2+ and codoped with Ce3+/Eu2+ and Eu2+/Dy3+ ions have been developed by an ‘amorphous based metal complex method’ using a water soluble silicon compound. The phase purity of the phosphors has been verified by X-ray powder diffraction technique. RBS:Ce3+(4%) phosphor exhibits a broad excitation spectrum in UV spectral region and a broad emission band centred at ∼439 nm with a full-width at half-maximum of ∼85 nm under the UV excitation. RBS:Eu2+ phosphor showed intense cyan-green emission which has been found to increase by three times in Ce3+/Eu2+ co-doped phosphors owing to the energy transfer from Ce3+ to Eu2+ in RBS:Ce3+, Eu2+ phosphor. Moreover, by co-doping RBS with Eu2+ and Dy3+ ions, the cyan-green emission of Eu2+ has been found to enhance considerably; about 6.9 times higher as compared to the emission intensity of RBS:Eu2+ phosphor. This increase is attributed to the generation of large number of traps similar to the pre-existing traps as a result of the incorporation of Dy3+ ion in RBS host and the enhancement in PL has also been substantiated from the enhanced thermoluminescence intensity of RBS:Eu2+, Dy3+ phosphor with respect to RBS:Eu2+ phosphor. Although the afterglow duration of RBS:Eu2+ and RBS:Eu2+, Dy3+ phosphors are in the similar range, but the afterglow intensity of half maxima was found to be 1.63 times higher in RBS:Eu2+,Dy3+ as compared to RBS:Eu2+ which owes to the enhanced photoluminescence intensity of the former as compared to the latter. The short but intense afterglow of RBS:Eu2+,Dy3+ phosphor indicates its potential for making glow bullet for defense application. Furthermore, when compared with, the photoluminescence (PL) emission intensity of near UV- excitable RBS:Eu2+, Dy3+ phosphor has been found to be ∼2 times higher than the green emitting commercial phosphor from Intermix reflecting the potential of this phosphor for the fabrication of phosphor-converted LED.