Photoluminescence properties of silica monoliths codoped with terbium and germanium

We prepared SiO2 monoliths doped with 1 mol% of Tb3+ ions and 1, 3, 5, 10 and 15 mol% of GeO2 via the sol–gel process. The xerogels were sintered at 1100 °C in air during three hours. We also prepared materials in a H2/Ar reductive atmosphere at 550 °C. We studied the luminescent properties of these materials. Among the most important results, we found that the distribution of the Tb3+ ions in the materials network is homogeneous. In addition, the incorporation of GeO2 in the silica network leads to the quenching of the emission signals of Tb3+, due to an energy transference process from the dopant to the SiO2-GeO2 matrix.