Luminescence of Er3+-doped nanostructured SiO2-LaF3 glass-ceramics prepared by the sol-gel method

Transparent glass ceramics with composition of 95SiO(2)-5LaF(3) doped with 0.1 mol% of Er3+ were synthesized by thermal treatment of precursor sol-gel glasses. Segregated LaF3 nanocrystals in the glass were confirmed from a structural analysis performed by X-ray diffraction. Blue, green and red efficient up-conversion emissions were observed under 980 nm excitation at room temperature. Under this excitation near infrared down-conversion at 1.55 mu m is also observed. These results could be attributed to the precipitation of LaF3 nanocrystals and the incorporation of most Er3+ ions in these nanocrystals. The mechanisms involved in the up-conversion emissions could be ascribed to two and three photon processes. (c) 2006 Elsevier B.V. All rights reserved.