Warm White Light Emission from Dy3+-Doped Mixed Alkaline-Earth Zinc Silico-Aluminate Glass Under Ultra-Violet Excitation

A series of Dy3+-doped mixed alkaline-earth zinc silico-aluminate glasses (CSrZSA14: xDy2O3; x = 0.1, 0.25, 0.5, 1.0 and 2.0 mol%) have been synthesized through melt-quenching technique to elucidate their physical, thermal and luminescence characteristics and the results are reported here. The X-ray diffraction confirms the non-crystalline nature of the prepared glass samples. A good thermal stability (ΔT) of ~163 °C has been established for the prepared glasses from DSC analysis. Further, the glass transition temperature (Tg) is decreased with increasing molar concentration of Dy2O3 in CSrZSA14 glass systems. The measured emission spectra of CSrZSA14:Dyx glasses with a variation of concentrations of Dy2O3 under 351 nm excitation have displayed four characteristic 4f–4f intra-band transitions. It is found that beyond 0.5 mol% of Dy2O3, the concentration quenching effect is significant due to Dy3+–Dy3+ interactions. The yellow to blue luminescence intensity ratio (Y/B) is varied from (1.80–1.97) and CSrZSA14Dy0.5 glass has the lowest Y/B ratio (1.80) among all the doped glasses. The measured decay time of CSrZSA14Dy0.5 glass is 438 µs. The chromaticity coordinates (x, y), color rendering index (CRI), and correlated color temperature (CCT) for all the glass samples are evaluated from the CIE diagram 1931. The temperature dependant photoluminescence of CSrZSA14Dy0.5 upon 365 nm laser excitation reveals that the relative emission intensity at 150 °C temperature is 85% compared to room temperature (25 °C). Hence, CSrZSA14Dy0.5 glass is a suitable candidate for warm white light and yellow laser light applications amongst all the prepared glass samples.