Enhancing luminescence performance via adjusting the doping concentration and boron aluminum ratio in Dy3+ -activated barium-boroaluminosilicate glasses for laser and W-LED applications

A series of barium-boroaluminosilicate [30SiO2-11Al2O3-44B2O3-5BaO-(10-x)K2O-xDy2O3 (with x = 0.25, 0.5, 0.75, 1.0, 1.25, 1.5 mol%)] glasses doped with Dy3+ ions were prepared by the high temperature (melt quenching) method. In the glass matrix, the relationship among structure, luminescence properties, and B/Al ratio was analyzed; also studied are the physical properties of glass and influence of Dy3+ concentration on the luminescence properties. Differential Scanning Calorimeter (DSC) results have shown the glass matrix exhibiting good thermal stability and high resistance to crystallization. FTIR and Raman spectra have confirmed the presence of stretching and bending vibrations of [BO3], [AlO4] and [SiO4] structural units in the prepared glass. The observed UV-Vis-NIR spectra have indicated that the existence of thirteen bands corresponding to the transition Dy3+ ions from 6H15/2 level to different excited levels; the transmittance curves obtained have shown the transmittance up to 91 %. Increase in Dy3+ concentration is found to decrease the optical band gap; the calculated Judd-Oflet parameter is found to follow the trend Ω2＞Ω4＞Ω6. Photoluminescence studies have shown three emission peaks which could be associated to the transitions: 4F9/2 → 6H15/2 (blue light), 4F9/2 → 6H13/2 (yellow light), and 4F9/2 → 6H11/2 (red light); the maximum intensity obtained for the glass with x = 0.75 mol%, with spacing between Dy3+ ions being 1.9137 Å; and the decay curve could be fitted with double exponential function. The CIE results have revealed that the chromaticity coordinates are closer to that of standard white light, and the color temperature located in the region of cold white light.