Synthesis, structural and morphological characterization and photoluminescence study of Y0.9Er0.1−xYbxVO4 materials

Abstract

Erbium/ytterbium-dopped Y0.9Er0.1−xYbxVO4 samples with x = 0, 0.01, 0.05 and 0.09 were synthesized by hydrothermal synthesis at basic pH with urea addition. For comparison purposes, another sample with x = 0 was also prepared by the solgel method. X-ray diffraction patterns were indexed on the basis to a tetragonal symmetry of space group I41/amd with Z = 4 compatible with a zircon-type, in good agreement with FTIR spectra. Additionally, some of the samples were coated with silica, and the successful coating process was verified in both X-ray diffraction profiles and FTIR spectra. Particles of two different morphologies were found in transmission electron microscopy images of uncoated samples, some spherical with sizes between 14 and 20 nm and others elongated. A shell of ~ 5 nm thickness was also observed in silica covered samples. The relationship between dopant content and the luminescence emission was systematically explored. Erbium-doped samples exhibit bright green fluorescence under stimulation at 360 nm. The substitution of erbium by ytterbium successfully produced an up-conversion emission under stimulation at 808 nm, being able to observe green and red emission bands. The potential use as fluorescent thermometers of erbium/ ytterbium doped samples at 300, 325 and 350 K was finally investigated