Sonochemical synthesis of highly luminescent Ln(2)O(3):Eu3+ (Y, La, Gd) nanocrystals

Sonication of Ln(CH3COO)(3)center dot H2O, Eu(CH3COO)(3)center dot H2O and NaOH dissolved in the ionic liquid-butyl-3-methylimidazolium bis(trifluoromethane)sulfonylamide lead to Ln(OH)(3):Eu (Ln: Gd, La, Y) nanoparticles. Subsequent calcination at 800 degrees C for 3 h allowed to obtain La2O3:Eu nanopowders. Gd2O3 and Y2O3 were obtained in the C-type lanthanide sequioxide structure, whereas La2O3 crystallized in the A-type. Structure, morphology, and luminescent properties of the nano-oxides were investigated by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), dispersive X-ray (EDX), and photoluminescence (PL). SEM studies revealed that the synthesized Gd2O3:Eu, La2O3:Eu, and Y2O3:Eu formed nano-spindle, -sheets, and -rods in shape, respectively. The nanoscale materials show very efficient red emission due to the intraconfigurational f-f transitions of Eu3+. The quantum yields for La2O3:Eu (5%) were determined to be 4.2% for Ln=Gd, 13.8% for Ln=Y and 5.2% for Ln=La. The asymmetric ratio I-02/I-01 of Eu3+ varies from 5.3 for Gd2O3, to 5.6 for Y2O3 to 6.5 for La2O3, which increased the color chromaticity. (C) 2015 Published by Elsevier B.V.