Visible emission studies by UV light conversion in (Dy3+/Tb3+) ions pair activated zinc-bismuth-barium borotellurite glasses for achieving intense green and white light

Abstract

Both white light and green emission properties of (Dy3+/Tb3+) ions pair activated zinc-bismuth-barium borotellurite glasses were studied by ultraviolet light (UV:388 and 366 nm) conversion with a focus on down-conversion process. On the dependences of Tb3+ amounts with co-doping of Dy3+, densities of glasses, excitation, emission, area of the integration in percent, decay times, multipolar interactions, and most responsible photometric parameters are investigated in the current work. These co-activated glasses show a broad color production range (450–700 nm) covering of red (∼622 nm), green (∼545 nm), and blue (∼488 nm) colors under the stimulation of UV light wavelengths. The ratio from Yellow to blue emission was analyzed to study the site symmetry of Dy3+ surrounds. With 388 nm of UV radiation, the area of the integrated intensity under the green (Tb3+:545 nm) peak reaches a maximum of 87 %, while it falls under the yellow (Dy3+:575 nm) peak at about 13 %. The decay times of co-activated glasses were found in decreasing order, followed by fitting with a double-exponential function. The Reisfeld and Dexter's energy transfer mechanism confirmed the reduction in Dy3+ emission and its lifetime values through quadrupole-quadrupole interaction (f = 10). Moreover, photometric properties such as relative color temperatures, color coordinates, and color purity were also discussed and compared to discriminate the potentiality of the present fabricated glasses for use in both white light and green-emitting devices.