The influence of precursor chemistry on thermal decomposition and particle growth in a rapid microwave-assisted strategy was investigated, demonstrating the selective synthesis of small and ultrasmall luminescent lanthanide-doped NaGdF4 nanoparticles.

Single‐particle fluorescent probes with the capacity to infer specific intracellular conditions, for instance, have great application potential in the realm of biomedicine. Imaging techniques that improve our understanding of the fluorescence processes at a single‐particle level are thus instrumental in actualizing this potential. This study demonstrates the importance of implementing synergistic single‐particle spectroscopic techniques to gain a more comprehensive understanding of the optical anisotropy exhibited by upconverting erbium and ytterbium co‐doped lithium yttrium tetrafluoride (LiYF4:Yb3+/Er3+) microparticles. More specifically, optical trapping and single‐particle polarized emission spectroscopy is herein leveraged to provide a plausible explanation for the spatial emission intensity distribution variation exhibited by LiYF4:Yb3+/Er3+ microparticles during hyperspectral imaging. By probing the polarized emission stemming from a single, optically trapped LiYF4:Yb3+/Er3+ microparticle, it is possible to find evidence that the emission intensity anisotropy exhibited by the respective microparticles during hyperspectral imaging arises as a consequence of the selection rules governing the emission probability in rare‐earth (RE3+) ions doped into a uniaxially birefringent host matrix such as LiYF4.

Eleven new lanthanide (Ln = Nd-Lu)-thiophene-2,5-dicarboxylic acid (25-TDC)-2,2':6',2''-terpyridine (terpy) coordination polymers () which employ a dual ligand strategy have been synthesized hydrothermally and structurally characterized by single crystal and powder X-ray diffraction. Two additional members of the series ( and ) were made with Ce(3+) and Pr(3+) and characterized via powder X-ray diffraction only. The series is comprised of three similar structures wherein differences due to the lanthanide contraction manifest in Ln(3+) coordination number as well as the number of bound and solvent water molecules within the crystal lattice. Structure type I (Ce(3+)-Sm(3+)) contains two nine-coordinate Ln(3+) metal centers each with a bound water molecule. Structure type II (Eu(3+)-Ho(3+)) features a nine and an eight coordinate Ln(3+) metal along with one bound and one solvent water molecule. Structure type III (Er(3+)-Lu(3+)) includes two eight-coordinate Ln(3+) metal centers with both water molecules residing in the lattice. Assembly into supramolecular 3D networks via π-π interactions is observed for all three structure types, whereas structure types II and III also feature hydrogen-bonding interactions via the well-known C-HO and O-HO synthons. Visible and near-IR luminescence studies were performed on compounds , , , and at room temperature. As a result characteristic near-IR luminescent bands of Pr(3+), Nd(3+), Sm(3+), and Yb(3+) as well as visible bands of Sm(3+) were observed.

Hierarchical nanostructured nanoparticles showing high values of relative thermal sensitivity and magnetization at low temperatures.

Well dispersed non-stabilized lanthanum oxyfluoride and fluoride nanoparticles were prepared in situ in thin silica films from rapid thermal decomposition of lanthanum tris-trifluoroacetate under nitrogen atmosphere. The thin silica films were obtained from sol-gel method and spin-coating. The spectroscopic properties of the non-stabilized nanoparticles as well the nanoparticles dispersed into thin silica films were studied in order to apply the system in future photonic applications such as erbium(III)-doped waveguide amplifiers. The non-stabilized nanoparticles were characterized by XRD, FT-IR, Transmission Electron Microscopy, Confocal Raman Spectroscopy and steady-state and timeresolved Luminescence Spectroscopy and these characterizations were used as a starting point to characterize the nanoparticles dispersed into the films. According to the temperature of the thermal treatments, the non-stabilized nanoparticles may present Eu(III)-doped LaOF in tetragonal and rhombohedral phases as well as a mixed phase of Eu(III)-doped LaF 3 and LaOF. The tetragonal LaOF phase has C 4v La(III) point symmetry and is more symmetric than the rhombohedral LaOF phase, where the La(III) ion has C 3v symmetry, consequently tetragonal LaOF presented lower U 2 values than rhombohedral LaOF. Theoretical calculations of Judd-Ofelt intensity parameters were also performed and were in good agreement with the experimental values. The samples containing the mixed phase of LaF 3 and LaOF presented lower values of intensity parameters than pure LaOF phases. The samples containing the mixed phase presented higher values of emission lifetimes and quantum efficiencies. Confocal Raman spectroscopy of these samples complements the luminescence studies and indicates which LaOF phase is present in the mixed phase of LaF 3 and LaOF. The rapid thermal decomposition of the precursor tris-trifluoroacetate on thin silica films results in well-dispersed 10 nm nanoparticles. The mixed phase of LaF 3 and LaOF phases is also present in thin films. The luminescence of the Eu(III) and Er(III)/Yb(III)-doped LaF 3 /LaOF nanoparticles containing thin silica films presented broad emission bands suggesting that in the future the systems may be applied as erbium(III)-doped waveguide amplifiers.

Nanocrystalline ZnO sponges doped with 5 mol% EuO1.5 are obtained by heating metal–salt complex based precursor pastes at 200–900 °C for 3 min. X‐ray diffraction, transmission electron microscopy, and extended X‐ray absorption fine structure (EXAFS) show that phase separation into ZnO:Eu and c‐Eu2O3 takes place upon heating at 700 °C or higher. The unit cell of the clean oxide made at 600 °C shows only ≈0.4% volume increase versus undoped ZnO, and EXAFS shows a ZnO local structure that is little affected by the Eu‐doping and an average Eu3+ ion coordination number of ≈5.2. Comparisons of 23 density functional theory‐generated structures having differently sized Eu‐oxide clusters embedded in ZnO identify three structures with four or eight Eu atoms as the most energetically favorable. These clusters exhibit the smallest volume increase compared to undoped ZnO and Eu coordination numbers of 5.2–5.5, all in excellent agreement with experimental data. ZnO defect states are crucial for efficient Eu3+ excitation, while c‐Eu2O3 phase separation results in loss of the characteristic Eu3+ photoluminescence. The formation of molecule‐like Eu‐oxide clusters, entrapped in ZnO, proposed here, may help in understanding the nature of the unexpected high doping levels of lanthanide ions in ZnO that occur virtually without significant change in ZnO unit cell dimensions.

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This paper describes a novel system which has a great potential for use for extractions in biotechnological processes as it uses only polymers and can be operated at moderate temperatures and salt concentrations. The polymers used in this work are ethylene oxide-propylene oxide 10:90 (w/w) (EO10PO90) and ethylene oxide-propylene oxide 20:80 (w/w) (EO20PO80). The temperature required for thermoseparation decreases with increasing PO content of the copolymer and increasing buffer concentration