Luminescence and structural characterization of transparent nanostructured Eu3+-doped LaF3–SiO2 glass–ceramics prepared by sol–gel method

Abstract Glass–ceramics with composition of 89.9SiO 2 –10LaF 3 –0.1EuF 3 (mol%) were prepared by sol–gel method. LaF 3 nanocrystals, precipitated by heat-treatments, were identified by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). Besides the well-known red emission of Eu 3+ ions, higher energy emissions coming from upper-lying levels 5 D 1 and 5 D 2 can be observed at room temperature due to the very low phonon energies of the LaF 3 matrix. Moreover, from site selective excitation and emission spectra in the temperature range from 13 to 300 K, it is concluded that the fraction of Eu 3+ ions partitioned into LaF 3 nanocrystals, substituting La 3+ ions, is comparable to the one staying in the SiO 2 glassy phase.