Growth, structural and optical characterizations of LiLa(1−x)Eux(WO4)2 single-crystalline fibers by the micro-pulling-down method

Transparent and uniform LiLa(1−x)Eux(WO4)2 single-crystalline fibers where x = 0.005, 0.01, 0.03, 0.05, 0.07, 0.1, 0.15, 0.2, 0.25 and 1.0, with an average of 20–40 mm length were obtained by the micro-pulling-down method aiming structural and optical characterization. The optimum pulling rate was found to depend on the difference between alkali and rare earth ionic radii. Rietveld analysis from X-ray diffraction data and excitation spectroscopy at room temperature were applied to investigate the lattice changes due to the Eu3+ incorporation in the host. LiLa(1−x)Eux(WO4)2 crystal fibers present red emission due to the electric dipole 5D0 → 7F2 transition under 395 nm excitation showing a concentration quenching around 20 mol% of doping. The excitation spectra of the 7F0 → 5D0 transition show small changes in the Eu3+ surroundings as function of dopant concentration.

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► Transparent and uniform LiLa(1−x)Eux(WO4)2 single-crystalline fibers were grown by the micro-pulling-down method.
► Alkali and rare earth ionic radii influence the pulling rate on the growth.
► Eu incorporation in LiLa(WO4)2 induces local distortions in the crystalline lattice.
► LiLa(1−x)Eux(WO4)2 single-crystalline fibers present intense red emission under 395 nm excitation.
► Concentration quenching observed in the emission around 20 mol% of Eu doping.