title: EPR and optical studies of erbium-doped beta-PbF2 single-crystals and nanocrystals in transparent glass-ceramics.
abstract: beta-PbF(2) single-crystals and nanocrystals in transparent glass-ceramics doped with ErF(3) have been synthesized and studied with two complementary techniques: electron paramagnetic resonance (EPR) and optical spectroscopy (absorption, selective excitation, fluorescence). A comparative study shows that, in both single-crystals and glass-ceramics, Er(3+) ions occupy the same types of sites, leading to similar optical properties. An EPR investigation demonstrates that, in these materials, part of the Er(3+) ions occupy cubic symmetry sites. For these ions, we determine the crystal field splitting of the ground state (4)I(15/2) and the symmetry of its sublevels. We also provide evidence for the presence of another type of Er(3+) ions, not detectable by EPR but evidenced by optical spectroscopy. We clearly show that this Er(3+), which gives rise to up-conversion luminescence, corresponds to clusters associating Er(3+) and F(-) ions. In the single-crystals, the proportion of these two types of erbium ions is estimated. It strongly depends on the doping rate of the beta-PbF(2) crystals.
authors.affiliation: Laboratoire de Chimie de la Matière Condensée de Paris, ENSCP, UMR 7574, 11 rue Curie, F- 75231, Paris Cedex 05, France.
authors.forename: Géraldine
authors.initials: G
authors.lastname: Dantelle
authors.forename: Michel
authors.initials: M
authors.lastname: Mortier
authors.forename: Daniel
authors.initials: D
authors.lastname: Vivien
mesh_terms: D000042:Absorption; D002516:Ceramics / Q000737:chemistry*; D003460:Crystallization; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D004871:Erbium / Q000737:chemistry / Q000145:classification*; D005459:Fluorides / Q000737:chemistry*; D007854:Lead / Q000737:chemistry*; D049449:Luminescence; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry*; D013053:Spectrophotometry / Q000379:methods*; D014961:X-Ray Diffraction
chemical_list: C077765:lead fluoride; D007854:Lead; D004871:Erbium; C023506:Glass ceramics; D005459:Fluorides