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 D-5(0) -> F-7(2) transition under 395 nm excitation showing a concentration quenching around 20 mol% of doping. The excitation spectra of the F-7(0) -> D-5(0) transition show small changes in the Eu3+ surroundings as function of dopant concentration. (C) 2011 Elsevier Ltd. All rights reserved.