Structural, morphology and luminescence study of Er+3-doped garnet-type Li5La3Nb2O12 electrolytes as a potential new phosphor

Abstract

Erbium doped garnet-type Li5La3Nb2O12 electrolytes were synthesized by conventional solid state reaction in air at 900 °C. Formation, microstructure and luminescence properties were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–VIS absorption and luminescence techniques. The limits of the Li5La3-xErxNb2O12 solid solution (0 ≤ x ≤ 0.05) were established by XRD and SEM. For x > 0.05, garnet structure coexists with segregated Er2O3. Rietveld refinement of room temperature powder XRD patterns shows that this solid solution exhibits a cubic garnet structure (a ~ 12.79 Å and S.G. Ia-3d) and trivalent Er ions replace La cations in cubic coordination (located in 24c site). The typical green, red and infrared luminescence of Er3+ ions can be efficiently excited under several wavelength lights in the UV–VIS–NIR region. Optical measurements have been improved dispersing Li5La3-xEr-xNb2O12 powder in KBr pellets. Our results indicate the potentiality of rare earth doped Li5La3Nb2O12 garnets as a new family of phosphors.