Visible erbium luminescence in SiO2–TiO2–Er3+ sol–gel powders

Spectroscopic properties of erbium ions in SiO 2 -TiO 2 -Er 3+ powders are studied and the nature of the emissions discussed. A strong green luminescence and less intense red and blue emissions were observed in the samples when exciting at 490 nm, 532 nm, 980 nm and 1532 nm. The excitation and emission mechanisms proposed were supported on experimental results, such as the lifetime decay times, the absorption spectra and the emission spectra.