Effect of germanium-codoping on the luminescence of terbium doped silica xerogels

Abstract The luminescence and excitation spectra of sol–gel derived silica containing up to 7.5 mol% Tb as well as of silica containing 1 mol% Tb and additionally up to 12 mol% Ge are reported. At 355 nm excitation, we demonstrate an increase of the Tb emission intensity due to Ge incorporation. The excitation spectra of both Tb and Tb–Ge doped silica change after heat treatment. We conclude, that electronic as well as structural defects play an important role for the Tb luminescence in silica xerogels.