• Schleid, Thomas
• Mudring, Anja-Verena
• Paterlini, Veronica
• Dorn, Katharina V.
• Goerigk, Felix C.

Abstract

<p>Pale yellow crystals of LnSb₂O₄Br (Ln = Eu-Tb) were synthesized via high temperature solid-state reactions from antimony sesquioxide, the respective lanthanoid sesquioxides and tribromides. Single-crystal X-ray diffraction studies revealed a layered structure in the monoclinic space group P2₁/c. In contrast to hitherto reported quaternary lanthanoid(III) halide oxoantimonates(III), in LnSb₂O₄Br the lanthanoid(III) cations are exclusively coordinated by oxygen atoms in the form of square hemiprisms. These [LnO₈]¹³⁻ polyhedra form layers parallel to (100) by sharing common edges. All antimony(III) cations are coordinated by three oxygen atoms forming ψ¹-tetrahedral [SbO₃]³⁻ units, which have oxygen atoms in common building up meandering strands along [001] according to (v = vertex-sharing, t = terminal). The bromide anions are located between two layers of these parallel running oxoantimonate(III) strands and have no bonding contacts with the Ln³⁺ cations. Since Sb³⁺ is known to be an efficient sensitizer for Ln³⁺ emission, photoluminescence studies were carried out to characterize the optical properties and assess their suitability as light phosphors. Indeed, for both, GdSb₂O₄Br and TbSb₂O₄Br doped with about 1.0-1.5 at-% Eu³⁺ efficient sensitization of the Eu³⁺ emission could be detected. For TbSb₂O₄Br, in addition, a remarkably high energy transfer from Tb³⁺ to Eu³⁺ could be detected that leads to a substantially increased Eu³⁺ emission intensity, rendering it an efficient red light emitting material.</p>

Topics

• impedance spectroscopy
• photoluminescence
• x-ray diffraction
• Oxygen
• layered
• forming
• space group
• Antimony