Geração de luz visível e estudo da transferência de energia em vidros TeO2:ZnO dopados e co-dopados com Dy3+/Pr3+ e Eu3+/Ho3+

Abstract

In this work, we carried out a spectroscopic study of glass based on Tellurium and Zinc oxides (xTeO2:yZnO), doped and co-doped with Dy3+/Pr3+ and Eu3+/Ho3+ ions, under UV and blue excitation. The analysis of this investigation was based on of optical absorption and excitation, luminescence, time-resolved luminescence measurements and energy transfer efficiency parameters. The results show that under UV/blue excitation the co-doped systems generate well-defined emission bands in the visible region, and the behavior of the emission intensity as a function of the co-dopant concentration indicated the presence of energy transfer mechanisms Dy3+ → Pr3+, Pr3+ → Dy3+, Eu3+ → Ho3+ and Ho3+ → Eu3+, which were later confirmed by lifetime measurements. The analysis of energy transfer efficiencies indicated that transfers according to Dy3+ → Pr3+ and Ho3+ → Eu3+ Dy3+ → Pr3+ and Ho3+ → Eu3+ mechanisms are more efficient and, therefore, are more likely to occur. It was also observed that the emissions are sensitive to the employed excitation wavelengths, and furthermore, these excitations are responsible for altering the sensitizer/activator relationship during the energy transfer process, showing, therefore, that the spectral profile of the emissions is a function not only of the ion concentration, but also of the excitation wavelength used and consequently of the energy transfer. The results presented here may impact studies that explore the optical properties of devices based on the light emitted by Dy3+/ Pr3+ and Eu3+/ Ho3+ ion pairs.