Influence of the rare earth ions concentration on luminescence properties of barium gallo-germanate glasses for white lighting

Barium gallo-germanate glasses co-doped with Ce3+ and Dy3+ were synthesized and their luminescence properties were studied using optical spectroscopy. The characteristic luminescence bands originating to electronic transitions of Ce3+ and Dy3+ ions were observed under direct excitation of Ce3+. Furthermore, the influence of rare earth ions concentration on luminescence properties of glass systems was examined. Luminescence lifetimes for the upper 4F9/2 excited state of Dy3+ ions were also evaluated and discussed in detail. The obtained experimental results indicate that energy transfer between these rare earth ions is possible. From the emission spectra, the Commission Internationale de I'Eclairage (CIE) chromaticity coordinates (x, y) are calculated in relation to potential application of germanate glass systems for white light emitting devices. It has been proved that our glass systems exhibit neutral/cool white emission originating from the simultaneous generation of several bands of Ce3+ and Dy3+ under the UV-visible light excitation.