Energy Transfer in Dy(3+) and Tb(3+) Double-Doped Barium Borate Glass

In this work, single- and double-doped Dy3+ and Tb3+ barium borate glasses are investigated for their potential as light converters. The density and the absorption coefficient show linearly increasing trends with an increasing lanthanide content. The external quantum efficiency of the double-doped samples is a combination of the respective single-doped samples. The strong energy transfer from Dy3+ to Tb3+ results in an intense Tb3+-related emission, i.e., an intense green luminescence. Thus, excitation at a Dy3+-related wavelength of 452 nm enables a Tb3+-related emission, at which a single-doped Tb3+ sample barely shows any luminescence. Lifetime measurements show that there is not only an energy transfer from Dy3+ to Tb3+, but also vice versa.