Luminescência e transferência de energia em vidros dopados com íons terras raras Tr³+ (Tm, Ho, Tb, Sm, Dy)

Abstract

In this work, I present the investigation of luminescent properties and the study of the energy transfer process between rare-earth ions inserted as doping agents in the fluorogermanate (80PbGeO3:10PbF2:10CdF2 and 70PbGeO3:15PbF2:15CdF2) and zinc tellurite (60Te2. 40ZnO) vitreous compounds which were then doped with Tm3+, Ho3+ Tb3+, Sm3+ and Dy3+. The objective of the investigation was to study the optical properties, characterization and color tuning of these luminescent materials from the glass doping and the energy transfer mechanism between the ions. The glass samples used in this work were excited with lasers at 355, 375 and 1064 nm. We analyzed the 80PbGeO3:10PbF2:10CdF2 glassy matrix doped with Tm3+/Ho3+, excited via upconversion, with a 1064 nm laser, investigating energy transfer and color tuning in the magenta region. In the 70PbGeO3:15PbF2:15CdF2 sample, doped with Tb3+/Sm3+under at 355 and 375 nm excitation, we investigated the energy transfer from Tb3+ to Sm3+ and the color tuning from green to red. The Tm3+/Dy3+ doped 60TeO2. 40ZnO glassy matrix was excited via downconversion and upconversion. Experimental data showed that in both cases there is energy transfer from Tm3+ to Dy3+ and three energy transfer routes were identified. The last study presented in this thesis involves the analysis performed in Tm3+/Tb3+/Sm3+ doped 60TeO2. 40ZnO glass, which generated white light and revealed energy transfer mechanisms from Tm3+ to Tb3+, from Tm3+ to Sm3+ and from Tb3+ to Sm3+. The results obtained with this investigation suggest that the vitreous materials used provide a considerable response to doping with rare earth ions, allowing the generation of tunable light and, therefore, it is possible to reach the chromaticity diagram desired region, in addition to allowing to vary the color temperature. The energy transfer processes that occur between the suggested ions and the color tuning proved to be quite efficient and favorable from the point of view of intelligent lighting.