Enhancement of Emission Intensity in Dy ³⁺ -Doped ZnO/ZnF <sub/>2</sub> Phosphoborate Glasses for W-LED Materials

摘要： Presently, white light emitting diodes (W-LEDs) were be used to substitute for conventional incandescent and fluorescent lamps due to their advantages; thus, it gets attention to create Dy3+-doped zinc phosphoborate glasses for enhancing better lightness. In this research, the replacing of ZnO by ZnF2 in 49B2O3:30P2O5:(20-x)ZnO:xZnF2:1Dy2O3 glasses, 0 ≤ x ≤ 20 mol% were prepared by melt quenching method and investigated through optical absorption and photoluminescence properties. The absorption results can be used for calculating the Judd-Ofelt (JO) intensity parameters (Ωλ, λ = 2, 4 and 6) and led to predicting the stimulated emission in present glasses. The trend of JO parameters is found to be Ω2 > Ω4 > Ω6 for all glasses. Nevertheless, replacing of ZnF2 does not affect position and intensity of optical absorption of Dy3+-doped glasses, whereas the observed blue (481 nm), yellow (573 nm) and red (662 and 752 nm) emission intensities of photoluminescence spectra rise with ZnF2 contents; the emission intensity at 573 nm for 20ZnF2 show the highest and was higher than 20ZnO around 1.6 times. The emission color of Dy3+-doped zinc phosphoborate glasses has been evaluated with CIE 1931 chromaticity diagram. The results revealed that all glasses emit white light. Hence, these glasses may be suitable candidate for using in W-LED and lighting materials.