Structural studies of nanoparticles doped with rare-earth ions in oxyfluoride lead-silicate glasses

Formation of PbF2 nanoparticles as up-conversion luminescent centers in oxyfluoride lead-silicate glass matrixes doped with rare-earth oxides has been studied by means of small-angle neutron scattering and neutron diffraction methods. During a two-stage heat treatment process, amorphous nanoparticles with sizes of similar to 5-7 nm were initially formed, then were aggregated into more complex clusters with average dimensions up to similar to 30 nm. The thermal treating at higher temperature led to crystallization of amorphous nanoparticles and, as a result, the formation of up-conversion luminescent centers in studied lead-silicate glasses. The sizes of amorphous and crystalline nanoparticles, fractional dimensions of density fluctuations in glass materials, as well as the lattice parameters of a phase of PbF2 were calculated.