Structural, Spectroscopic, and Magnetic Properties of Eu³⁺-Doped GdVO₄ Nanocrystals Synthesized by a Hydrothermal Method

Abstract

New interesting aspects of the spectroscopic properties, magnetism, and method of synthesis of gadolinium orthovanadates doped with Eu(3+) ions are discussed. Gd(1-x)Eu(x)VO4 (x = 0, 0.05, 0.2) bifunctional luminescent materials with complex magnetic properties were synthesized by a microwave-assisted hydrothermal method. Products were formed in situ without previous precipitation. The crystal structures and morphologies of the obtained nanomaterials were analyzed by X-ray diffraction and transmission and scanning electron microscopy. Crystallographic data were analyzed using Rietveld refinement. The products obtained were nanocrystalline with average grain sizes of 70-80 nm. The qualitative and quantitative elemental composition as well as mapping of the nanocrystals was proved using energy-dispersive X-ray spectroscopy. The spectroscopic properties of red-emitting nanophosphors were characterized by their excitation and emission spectra and luminescence decays. Magnetic measurements were performed by means of vibrating sample magnetometry. GdVO4 and Gd0.8Eu0.2VO4 exhibited paramagnetic behavior with a weak influence of antiferromagnetic couplings between rare-earth ions. In the substituted sample, an additional magnetic contribution connected with the population of low-lying excited states of europium was observed.

Room-temperature fabrication of light-emitting thin films based on amorphous oxide semiconductor

“…1, excitation energy (E ex ) for PL centered at 4.59 eV. The excitation mechanism for Eu 3+ ions has been explained by a CT process, 16,17 which is consistent with our observation of the CT band (CTB) in the PLE spectrum. As illustrated in the energy level diagram, the highest occupied state of Eu 3+ 4 f is around 1 eV below the E VBM .…”

“…On the other hand, PLE spectra of the 614 nm emission exhibited a broad band centered at 270 nm (4.59 eV), which is known to be a charge-transfer (CT) process. 16,17 As shown in Fig. 1(b), we observed intense red emission from the room-temperature fabricated a-IGZO:Eu 0.3 thin films under 270 nm monochromated light illumination.…”

“…As will be explained later, strong PL were observed in a-IGZO:Eu x films deposited at room temperature when the (In 2−x Eu x )GaZnO y target with x = 0.3 was used and the deposition condition was optimized to P O2 = 5 Pa. Figure 1( 6,16,17 The strongest emission was the 5 D 0 → 7 F 2 electric dipole transition at 614 nm. On the other hand, PLE spectra of the 614 nm emission exhibited a broad band centered at 270 nm (4.59 eV), which is known to be a charge-transfer (CT) process.…”

Silk fibroin-antigenic peptides-YVO 4 :Eu 3+ nanostructured thin films as sensors for hepatitis C

“…This Eu 3 þ bands region is zoomed in the inset for clearer observation. A broader band is observed peaking at around 300 nm, assigned to a composition of the O 2-Eu 3 þ and the O 2-V 5 þ charge transfer states, which efficiently populate the Eu 3 þ emitting states [27,28]. Just the broad band is observed for the composite film suggesting that the Eu 3 þ emission is efficiently excited through the already mentioned charge transfer states together with the aromatic amino acids present in the medium and which absorption occurs at that spectral region.…”

Photochemical studies of monodispersed YPO 4 :Eu microspheres: The role of surface modification on structural and luminescence properties

“…The observed orange and red emission from Eu 3+ is incorporated to the biological window to trace the particular biomolecules [1,12]. These materials are generally produced red emission by excitation from the ultraviolet region (395) nm [13][14][15]. Thus, these Eu-doped yttrium phosphate nanomaterials have been optimized for application in the display panel, fluorescent lamps and optical diodes [8,16,17].…”