Search results for "LANTHANIDE"
showing 10 items of 230 documents
Eu3+ ion distribution in oxyfluoride glass nanocomposites
2019
The authors are grateful to Dr. Andris Fedotovs for photography of the samples. This research is funded by the Latvian Council of Science, project “Novel transparent nanocomposite oxyfluoride materials for optical applications”, project No. LZP-2018/1-0335.
Lanthanide-doped Y3Ga5O12 garnets for nanoheating and nanothermometry in the first biological window
2018
Abstract Absorption and luminescence spectra in the first biological window of Nd3+ single-doped and Er3+-Yb3+ co-doped Y3Ga5O12 nano-garnets have been studied to evaluate their potential use as simultaneous optical nanoheaters and nanothermometers in biomedicine. Nd3+-doped nano-garnets uses the 808 nm laser radiation, resonant with the largest absorption peak of the 4I9/2 → 4F5/2 transition, for both heating the nanoparticle and populating the 4F3/2 emitting level. Changes in the relative intensities of different emission peaks between Stark levels of the 4F3/2 (R1,2)→4I9/2 (Z1-5) transition can be directly related to the temperature of the nano-garnet. On the other hand, the Yb3+/Er3+com…
Electronic, Structural and Functional Versatility in Tetrathiafulvalene-Lanthanide Metal-Organic Frameworks
2019
<div>Tetrathiafulvalene-Lanthanide (TTF-Ln) Metal-Organic Frameworks (MOFs) are an interesting class of multifunctional materials in which porosity can be combined with electronic properties such as electrical conductivity, redox activity, luminescence and magnetism. Herein we report a new family of isostructural TTF-Ln MOFs, denoted as <b>MUV-5(Ln)</b> (Ln = Gd, Tb, Dy, Ho, Er), exhibiting semiconducting properties as a consequence of the short intermolecular S···S contacts established along the chain direction between partially oxidised TTF moieties. In addition, this family shows photoluminescence properties and single-molecule magnetic behaviour, finding near-infrared …
Influence of Ce codoping and H2 pre-loading on Er/Yb-doped fiber: Radiation response characterized by Confocal Micro-Luminescence
2011
International audience; Confocal microscopy luminescence measurements were applied to study the X-ray radiation response of Er/Yb-doped optical fibers in connection with H2 pre-loading and with the addition of another lanthanide element (Cerium) in the core composition. Laser excitations at 488 nm and 325 nm allow deriving the emission and absorption pattern of Er3+, the latter derived from the dips appearing in a wide luminescence band related to defects in silica. We found that the luminescence spectrum of the X-irradiated Er/Yb-doped core fiber evidences an increase in the emission intensity around 520 and 660 nm; in contrast, no changes are induced by radiation neither after H2 pre-load…
Influence of thermally induced structural transformations on the magnetic and luminescence properties of tartrate-based chiral lanthanide organic-fra…
2020
This work reports on the synthesis and characterization of five enantiomeric pairs of isostructural 3D metal-organic frameworks (MOFs) with the general formula {[Ln2(μ4-tar)2(μ-tar)(H2O)2]·xH2O}n [where Ln(iii) = Tb (Tb-L and Tb-D), Dy (Dy-L and Dy-D), Ho (Ho-L and Ho-D), Er (Er-L and Er-D) and Tm (Tm-L and Tm-D); tar = tartrate (d- or l-) and x = 3 or 4 depending on the counterpart], which possess interesting luminescence and magnetic properties. These MOFs undergo progressive and reversible dehydration processes upon controlled heating yielding three crystalline phases (Ln-L′, Ln-L′′ and Ln-L′′′). Alternating current magnetic measurements on Tb, Dy and Er-based compounds exhibit field ind…
A magnetic study of a layered lanthanide hydroxide family: Ln8(OH)20Cl4·nH2O (Ln = Tb, Ho, Er)
2018
Three layered lanthanide hydroxides (LLHs), with the general formula Ln8(OH)20Cl4·nH2O (Ln = Tb (1), Ho (2), Er (3)), were prepared and magnetically characterized. These compounds were further diluted within a yttrium diamagnetic matrix, LYH:xLn, LYH:0.044Tb (1’), LYH:0.045Ho (2’), and LYH:0.065Er (3’), being the study complemented with theoretical calculations in order to understand the electronic configuration and the contributions to the slow relaxation behavior. In the pure compounds dominant 3D ferromagnetic interactions are observed, with a small magnetization hysteresis at 1.8 K for 1, while the magnetically diluted solid solutions display slow relaxation of the magnetization at low …
Hybrid organic-inorganic mononuclear lanthanoid single ion magnets
2019
The first family of hybrid mononuclear organic-inorganic lanthanoid complexes is reported, based on [PW11O39]7− and 1,10-phenanthroline ligands. This hybrid approach causes a dramatic improvement of the relaxation time (×1000) with a decrease of the optimal field while maintaining the Ueff of the inorganic analogues.
Adsorption of Rare Earth Elements onto DNA-Functionalized Mesoporous Carbon.
2020
The recovery and separation of rare earth elements (REEs) are of national importance owing to the specific usages, high demand, and low supply of these elements. In this research, we have investigated the adsorption of rare earth elements onto DNA-functionalized mesoporous carbons with a BET surface area of 605 m2/g and a median mesopore width of 48 A. Three types of single-stranded DNA, one with 100 base units of thymine, another with 20 units of thymine, and the third, a 2000 unit long DNA from salmon milt were grafted on the carboxylated mesoporous carbon surface. All of the DNA-functionalized mesoporous carbons demonstrated higher adsorption of REEs compared to pristine mesoporous carbo…
A broadening temperature sensitivity range with a core-shell YbEr@YbNd double ratiometric optical nanothermometer.
2016
The chemical architecture of lanthanide doped core–shell up-converting nanoparticles can be engineered to purposely design the properties of luminescent nanomaterials, which are typically inaccessible to their homogeneous counterparts. Such an approach allowed to shift the up-conversion excitation wavelength from ∼980 to the more relevant ∼808 nm or enable Tb or Eu up-conversion emission, which was previously impossible to obtain or inefficient. Here, we address the issue of limited temperature sensitivity range of optical lanthanide based nano-thermometers. By covering Yb–Er co-doped core nanoparticles with the Yb–Nd co-doped shell, we have intentionally combined temperature dependent Er u…
Core–Shell Engineering to Enhance the Spectral Stability of Heterogeneous Luminescent Nanofluids
2017
This work was supported by the Spanish Ministerio de Educación y Ciencia (MAT2016-75362-C3-1-R) and by COST Action CM1403. L.L.-P. thanks the Universidad Autónoma de Madrid for the ‘‘Formación de Personal Investigador (FPI-UAM)’’program. P.H.-G. thanks the Spanish Ministerio de Economia y Competitividad for the Juan de la Cierva program (IJCI-2015-24551). M.P. and A.S. thank University of Verona (Italy) for financial support in the framework of the ‘‘Cooperint 2016’’ and “Ricerca di Base 2015” projects. The work of K.S. was supported by Latvian National Research Program IMIS2 (Grant No. 302/2012).