Ternary Rare Earth Research Articles

Preparation, luminescence and thermal properties of lanthanide complexes with 2-chloro-4-fluorobenzoic acid

Three new solid ternary lanthanide complexes of [Ln(2-Cl-4-FBA) 3phen] 2 (Ln = Eu 3+(1), Tb 3+(2), Ho 3+(3), 2-Cl-4-FBA = 2-chloro-4-fluorobenzoate, phen = 1,10-phenanthroline) were synthesized and characterized by means of elemental analysis, IR and UV spectra and XRD. The complexes 1 and 2 emit bright red and green luminescence respectively under the excitation ultraviolet light at room temperature. Thermal analyses of the three complexes were discussed by TG–DTG and IR techniques. The heat capacities of the complexes were measured from 259.15 to 493.02 K by means of Differential scanning calorimetry (DSC). The relationship of the molar heat capacities varying with the reduced temperature ( x) ( x = [ T − ( T max + T min)/2]/[( T max − T min)/2]) was fitted to a polynomial equation with the least-squares method for each complex. Finally, the derived thermodynamic functions ( H T − H 298.15), ( S T − S 298.15) and ( G T − G 298.15) of the complexes relative to the standard reference temperature 298.15 K were also obtained on the base of the fitted polynomials and thermodynamic relationships.

Photophysical properties of ternary rare earth (Sm3+, Eu3+) centered hybrids with N-heterocyclic modified Si-O bridge and terminal ligands

5-Amino-1,10-phenanthroline (Phen-NH(2)) is grafted to 3-(triethoxysilyl)-propyl isocyanate (TESPIC) to achieve the organic precursor Phen-Si, which is coordinated to rare earth ions (Sm(3+) or Eu(3+)) and formed Si-O networks with tetraethoxysilane (TEOS) (Phen-Si-RE) after hydrolysis and polycondensation processes to obtain the hybrids Phen-Si-Ln. To investigate the influence of the second ligands to the photophysical properties of the hybrid material Phen-Si-RE, the organic ligand nicotinic acid (NA) and the polymers polyvinylpyrrolidone (PVP) (or PMMA) are further introduced into the above system to assemble the ternary hybrid materials Phen-Si-RE-NA and Phen-Si-RE-PVP (or Phen-Si-RE-PMMA), respectively. These hybrids are amorphous and especially the photophysical properties of them indicate that the introduction of the second ligands is favorable for the luminescence lifetime and quantum efficiency.

The First Lanthanide Telluride-Bromide: La3Te4Br, a Valence Compound

The first ternary lanthanide telluride-bromide La3Te4Br was obtained from a mixture of LaTe and LaBr3 (in the presence of iridium) in a sealed tantalum container at elevated temperatures. The crystal structure (orthorhombic, Pnma, a = 1634.3(2), b = 435.0(1), c = 1426.6(2) pm, Z = 4, R1 (I0 > 2s(I0)) = 0.0349) is built from dicapped trigonal prisms of tellurium and bromine atoms surrounding lanthanum in two different ways. The dicapped trigonal prisms are connected via common edges to a threedimensional structure, in the same fashion as is known for the binary U3Te5. La3Te4Br is a valence compound according to (La3+)3(Te2-)4(Br-) and one out of three lanthanide telluride-halides known to date.

Photofunctional ternary rare earth (Eu3+, Tb3+, and Sm3+) hybrid xerogels with hexafluoroacetylacetonate derived building block and bis(2-methoxyethyl)ether through coordination bonds

Abstract Hexafluoroacetylacetonate (HFAA) is functionalized with 3-(triethoxysilyl)-propyl isocyanate (TEPIC) to achieve a new molecular building block HFAASi. Then two series ternary hybrid xerogels of rare earth ions (Eu3+, Tb3+, and Sm3+) with HFAASi and special terminal ligands bis(2-methoxyethyl)ether (BME) have been assembled through coordination bonds, whose photoluminescence are studied in details.

Synthesis, characterization and luminescence property of ternary rare earth complexes with azatriphenylenes as highly efficient sensitizers

A series of novel ternary rare earth complexes showing attractive luminescence properties were prepared with both neutral and anion ligands. Three azatriphenylene neutral ligands, 1,10-phenanthroline (phen), dipyrido [3,2-a: 2′,3′-c] quinoxaline (dpq) and dipyrido [3,2-a: 2′,3′-c] phenazine (dppz) were investigated systematically as sensitizers in the ternary rare earth complexes. Benzoate ions (BA −) and phenoxyacetate ions (POA −) were chosen as anion ligands. The compositions of these complexes were characterized by elemental analysis, rare earth coordination titration, molar conductivity measurement, IR spectroscopy, UV–vis absorption spectroscopy, 1H NMR spectroscopy and TGA–DTA. The luminescence spectra, luminescence decay time and quantum efficiency of the complexes were also studied. The very strong luminescence intensities and rather long luminescence lifetimes (typically > 1.0 ms) were achieved for both Eu 3+ and Tb 3+ ternary complexes with phen and dpq as neutral ligands. Moreover, high quantum efficiencies (40–60%) were also obtained for Eu 3+ ternary complexes with phen and dpq as neutral ligands.

Electrical and Structural Properties of Ternary Rare-Earth Oxides on Si and Higher Mobility Substrates and Their Integration as High-k Gate Dielectrics in MOSFET Devices

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Cooperative sol–gel assembly, characterization and photoluminescence of rare earth hybrids with novel dihydroxyl linkages and 1,10-phenanthroline

A novel series of photoactive binary and ternary rare earth (Eu 3+, Tb 3+) hybrids with organic parts covalently bonded to inorganic parts via hydroxyl linkage and 1,10-phenanthroline (Phen) have been cooperative assembled through a sol–gel process. Two molecular bridges are used as covalent linkage from the functionalization of 4-vinylbenzeneboronic acid (VBBA) by two different silane crosslinking reagents (3-chloropropyl-trimethoxysilane (CPTMS) and 3-aminopropyltriethoxysilane (APTES)) after the copolymerization with acrylic acid, which mainly behave as structural unit to form the Si–O network. Besides, Phen is fabricated as the assistant functional ligand to sensitize the luminescence of rare earth ions. These hybrids are characterized and especially photophysical properties of them are studied in detail. Compared to binary hybrid materials RE–VC and RE–VA (RE = rare earth; VC = VBBA–CPTMS linkage; VA = VBBA–APTES linkage), ternary hybrid materials Phen–RE–VC and Phen–RE–VA exhibit stronger luminescence intensity, longer lifetime and higher quantum efficiency, proving that introduction of Phen improves luminescence of rare earth ions within hybrid system.

Photophysical Properties of Ternary Hybrid System of Lanthanide Center Linking Organically Modified Silica and Polymeric Chain

According to coordination chemistry principle and molecular assembly technology, series of ternary lanthanide centered hybrid systems have been constructed through coordination bonds. Among one component (ligand) is organically modified Si-O network, which originates from the functional molecular bridge (BFPPSi) by the functionalization of 1,3-bis(2-formylphenoxy)-2-propanol (BFPP) with 3-(triethoxysilyl)propyl isocyanate. In the second component (ligand), three different organic polymeric chains are introduced, poly-(methyl methacrylate) (PMMA, from the polymerization of MMA with the benzoyl peroxide [BPO] as the initiator), poly-(methyl acrylic acid) (PMAA, from the polymerization of MAA with the BPO as the initiator), polyvinyl pyridine, respectively. All these ternary hybrid materials show homogeneous, regular microstructure, suggesting the existence of assembly process of lanthanide centers, inorganic Si-O network and organic polymer chain. Compared to the binary hybrids without polymer chain, the photoluminescent properties of these ternary hybrids present stronger luminescent intensities, longer lifetimes and higher luminescent quantum efficiencies indicating that the introduction of organic polymer chain is favorable for the luminescence of the whole hybrid systems.

Coordination bonding construction, characterization and photoluminescence of ternary lanthanide (Eu3+, Tb3+) hybrids with phenylphenacyl-sulfoxide modified bridge and polymer units

A novel polysilsesquioxane bridge (PPSSi) is synthesized with methylene group modification of phenylphenacyl sulfoxide by isocyanate group from 3-(triethoxysilyl)propyl isocyanate (TEPIC). Then ternary lanthanide (Eu, Tb) hybrids of polysilsesquioxane bridge (PPSSi) and four kinds of polymer chain (polyacrylamide (PAM), polyvinylpyrrolidone (PVP), polymethyl methacrylate (PMMA) and polyethyl methacrylate (PEMA) were assembled wth coordination bonding. To explore the influence of the different polymeric chains on the properties of lanthanide hybrids, the microstructure and photoluminescent properties of these lanthanide coordination polymer hybrids (PPSSi-Ln-PAM (PVP, PMMA, PEMA)) are compared in detail. Four organic polymer chains with different structures not only can coordinate to the lanthanide ions by their own carbonyl groups, but also can form a polymeric matrix together with the inorganic Si-O network. The results show that all the obtained hybrids could show efficient intramolecular energy transfer and lead to excellent characteristic emission of lanthanide ions. Moreover, the different structures of the polymers induce different microstructures and different photoluminescent behavior (lifetime and quantum efficiency) for these hybrid systems. The PPSSi-Ln-PMMA hybrid leads to the longest lifetime and highest quantum efficiency.

Structure and dynamics of binary and ternary lanthanide(iii) and actinide(iii) tris[4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione] (TTA) – tributylphosphate (TBP) complexes. Part 3, the structure, thermodynamics and reaction mechanisms of 8- and 9-coordinated binary and ternary Y-TTA-TBP complexes studied by quantum chemical methods

Possible mechanisms for intermolecular exchange between coordinated and solvent water in the complexes Y(TTA)(3)(OH(2))(2) and Y(TTA)(3)(TBP)(OH(2)) and intermolecular exchange between free and coordinated HTTA in Y(TTA)(3)(OH(2))(HTTA) and Y(TTA)(3)(TBP)(HTTA) have been investigated using ab initio quantum chemical methods. The calculations comprise both structures and energies of isomers, intermediates and transition states. Based on these data and experimental NMR data (Part 2) we have suggested intimate reaction mechanisms for water exchange, intramolecular exchange between structure isomers and intermolecular exchange between free HTTA and coordinated TTA. A large number of isomers are possible for the complexes investigated, but only some of them have been investigated, in all of them the most stable geometry is a more or less distorted square anti-prism or bicapped trigonal prism; the energy differences between the various isomers are in general small, less than 10 kJ mol(-1). 9-coordinated intermediates play an important role in all reactions. Y(TTA)(3)(OH(2))(3) has three non-equivalent water ligands that can participate in ligand exchange reactions. The fastest of these exchanging sites has a QM activation energy of 18.1 kJ mol(-1), in good agreement with the experimental activation enthalpy of 19.6 kJ mol(-1). The mechanism for the intramolecular exchange between structure isomers in Y(TTA)(3)(OH(2))(2) involves the opening of a TTA-ring as the rate determining step as suggested by the good agreement between the QM activation energy and the experimental activation enthalpy 47.8 and 58.3 J mol(-1), respectively. The mechanism for the intermolecular exchange between free and coordinated HTTA in Y(TTA)(3)(HTTA) and Y(TTA)(3)(TBP)(HTTA) involves the opening of the intramolecular hydrogen bond in coordinated HTTA followed by proton transfer to coordinated TTA. This mechanism is supported by the good agreement between experimental activation enthalpies (within parenthesis) and calculated activation energies 68.7 (71.8) and 35.3 (38.8) kJ mol(-1). The main reason for the difference between the two systems is the much lower energy required to open the intramolecular hydrogen bond in the latter. The accuracy of the QM methods and chemical models used is discussed.

Electrical transport properties of ternary phosphides RRu2P2 (R=La, Ce,Pr and Eu) with ThCr2Si2 type crystal structure

It was found the growth method of single crystals of ternary lanthanide transition metal phosphide RRu2P2 (R=La, Ce,Pr and Eu) with enough large volume to measure the macroscopic physical properties, such as magnetization, electrical resistivity and specific heat. As a result, we succeeded in the measurements of electrical resistivity with a sufficiently good accuracy and reveal an experimental evidence of the superconducting transition in LaRu2P2 for the first time. On the basis of the results of electrical resistivity measurements we discuss that how P-P bonding state does affect on the electrical transport properties of RRu2P2 compounds.

Synthesis and Characterization of Ternary Terbium Luminescence Complexes with Phthalic Acid and 1, 10-Phenanthroline

Ternary rare earth luminescence complexes composed of Tb (III)-phthalic acid (H2L)-1,10-phenanthroline (phen) were synthesized using precipitation method. The elemental analysis, plasma atomic emission spectra, infrared spectra were measured the composition of obtained samples and the chemical composition deduced is TbL3/2(phen)0.5. XRD patterns show that the obtained coordination compound is new crystal different from that of two ligands. SEM results indicate that the coordination compound is a floral crystal with the size about 1-2 µm and has better dispersity. The TG-DTA result showed that the luminescence complex has good stability below 478 oC. Photoluminescence analysis indicated that the coordination compound emits Tb3+ characteristic green luminescence under ultraviolet excitation.

Theoretical prediction of topological insulator in ternary rare earth chalcogenides

A new class of three-dimensional topological insulator, ternary rare earth chalcogenides, is theoretically investigated with ab initio calculations. Based on both bulk band structure analysis and the direct calculation of topological surface states, we demonstrate that LaBiTe3 is a topological insulator. La can be substituted by other rare earth elements, which provide candidates for novel topological states such as quantum anomalous Hall insulator, axionic insulator and topological Kondo insulator. Moreover, YBiTe3 and YSbTe3 are found to be normal insulators. They can be used as protecting barrier materials for both LaBiTe3 and Bi2Te3 families of topological insulators for their well matched lattice constants and chemical composition.

Spectroscopic study of intramolecular energy transfer in a phosphine oxide Eu 3+ complex: A stepwise process induced by intermediate energy levels

The intramolecular energy transfer process in a ternary Europium(III) complex Eu(TTA) 3(TAPO) 2 ( 1, TAPO = (4-diphenylamine-phenyl)-diphenylphosphine oxide, TTA = 2-thenoyltrifluoroacetonate) was investigated with both steady-state and time-resolved spectroscopic approaches to figure out the detail of the energy transfer between the neutral and anion ligands. The energy transfer from the first singlet excited energy level (S 1) of the anion ligand TTA to the first triplet excited energy level (T 1) of TAPO was first proved. This discovery supports that when the neutral ligand has an appropriate T 1 level between the S 1 and T 1 levels of the anion ligand, the energy can be transferred from the S 1 energy level of the neutral ligands to 5D 0 of Eu 3+ through a stepwise process: S 1 TAPO → S 1 TTA → T 1 TAPO → T 1 TTA → D 0 E u 3 + 5 . This kind of sequential process makes intramolecular energy transfer more efficient, and is one of the most important factors resulting in the great improved photoluminescent performance of 1. It is shown that in ternary lanthanide complexes the efficient energy transfer between the neutral and anion ligands is crucial to the luminescent performance of the complex. And the intramolecular energy transfer can be facilitated by the ladder-like distribution of the excited energy levels.

Fluorescence enhancement of lanthanide(III) perchlorate by 1,10-phenanthroline in bis(benzoylmethyl) sulfoxide complexes and luminescence mechanism

Two novel ternary rare earth complexes LnL5L′(ClO4)32H2O (Ln=Eu(III), Tb(III); L=bis(benzoylmethyl) sulfoxide, L′=phen) were synthesized and characterized by elemental analysis, coordination titration analysis, molar conductivity, IR, TG–DSC,1H NMR and UV spectra. The fluorescence spectra illustrated that both the Eu(III) and Tb(III) ternary complexes displayed strong characteristic metal-centered fluorescence in solid state. After the introduction of the second ligand phen group, the relative emission intensities and fluorescence lifetimes of the ternary complex EuL5L′(ClO4)32H2O (L=C6H5COCH2SOCH2COC6H5, L′=phen) enhanced more obviously than that of the binary complex EuL5(ClO4)33H2O. This indicated that the presence of both organic ligands bis(benzoylmethyl) sulfoxide and the second ligand phen could sensitize fluorescence intensities of Eu(III) ions, and the introduction of phen group was resulted in the enhancement of the fluorescence properties of the Eu(III) ternary rare earth complexes. The phosphorescence spectra are also discussed.

Liquid Injection MOCVD Grown Binary Oxides and Ternary Rare-Earth Oxide as Alternate Gate-Oxides for Logic Devices

ZrO2, HfO2 and DyScO3 thin films having thickness in the range 2-20 nm were grown on SiOx/Si(100) substrates in a multi-wafer planetary MOCVD reactor combined with a liquid delivery system using engineered precursors. Growth rate, surface morphology, crystal structure, crystal density of the as-deposited films were analysed as a function of deposition temperature. The influence of post deposition annealing on the densification and crystallization was studied. Electrical properties of MIS capacitor structures are also discussed. Results on the optimised gate stack of Pt/ZrO2/SiOx/Si, Pt/HfO2/SiOx/Si, Pt/DyScO3/SiOx/Si are finally compared; and DyScO3 seems to be promising high-k material candidate compared to Group-IVB oxides for the coming technology nodes.

Improvement of the Electrochemical Performance of Ln0.58Sr0.4Fe0.8Co0.2O3 – δ IT‐SOFC Cathodes by Ternary Lanthanide Combinations (La‐Pr‐Sm)

AbstractActive perovskite‐based SOFC cathodes have been developed through lanthanide combination in the (La1 – x – yPrxSmy)0.58Sr0.4Fe0.8Co0.2O3 – δ system following a ternary mixture experimental design. These compositions were prepared through a sol–gel method and characterised by electrochemical impedance spectroscopy (EIS) as symmetrical cells on GDC‐electrolyte samples in the 450–650 °C temperature range. The electrochemical properties of the single lanthanide‐based Ln0.58Sr0.4Fe0.8Co0.2O3 – δ compounds were enhanced when different lanthanides were combined together in the same crystalline structure. The observed improvement does not follow a mere additional effect of the performance from the parent Ln0.58Sr0.4Fe0.8Co0.2O3 – δ compounds, i.e. it does not follow a linear behaviour, and the better performance is ascribed to synergetic catalytic effects among lanthanide cations. A reduction in electrode polarisation resistance with respect to non‐substituted compositions is stated for most Ln0.58Sr0.4Fe0.8Co0.2O3 – δ electrode compositions combining two or three lanthanides. Samarium addition to the electrode material involves a substantial reduction in the activation energy and the reduction degree is directly dependant on the samarium amount incorporated in the lattice. The best performing composition comprises a praseodymium‐rich lanthanum‐based electrode material. The experimental data derived from the ternary mixture design were modelled using nonlinear functions and this modelling allowed finding an electrode composition minimising the polarisation resistance while maintaining the activation energy at reduced values. Selected cathode compositions were tested in fully assembled anode‐supported cells and electrochemical characterisation supports the cooperative effect of lanthanide combination.

Ternary Rare Earth Inorganic–Organic Hybrids with a Mercapto‐Functionalized Si–O Linkage and a Polymer Chain: Coordination Bonding Assembly and Luminescence

AbstractA series of ternary organic/inorganic/polymer hybrid materials have been assembled on the basis of the coordination chemistry principle. Mercapto‐functionalized MBA‐Si from MBA (4‐mercaptobenzoic acid) behaves as the first coordination unit, which forms sulfide linkages, resulting in an inorganic Si–O network after hydrolysis and copolycondensation with TEOS (tetraethoxysilane). The organic polymers PVPD [poly(4‐vinylpyridine)] and PMMA [poly(methyl methacrylate)] play a role of the second coordination unit, whose organic polymeric C–C chain originates from addition polymerization of the monomers 4‐VPD (4‐vinylpyridine) and MMA (methyl methacrylate), respectively. These hybrids are characterized in detail to compare with the binary hybrids without an organic polymer unit, whose results reveal that the microstructure, the thermal stability, and especially the photoluminescence properties of the hybrid system are improved with the introduction of the polymer as the coligand.

Liquid Injection MOCVD Grown Binary Oxides and Ternary Rare-Earth Oxide as Alternate Gate-Oxides for Logic Devices

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Photoactive Ternary Rare Earth Complex Hybrids with Sulfoxide Functionalized Silica and PMMA (or Phen)

A series of ternary rare earth complexes were covalent grafted to the inorganic Si-O networks through the novel bifunctional silylated monomer BBMSSi (BBMS = Bis [benzoylmethyl] sulfoxide). FT-IR, NMR, XRD, TGA, SEM, DRS and photoluminescence properties were used to characterize the obtained hybrid materials. Scanning electron micrograph results revealed hybrids exhibiting homogeneous morphology with large particle size of 100-200 microm and no phase separation. Photoluminescence measurements indicated hybrids with characteristic red and green luminescence. In addition, the existence of the polymeric chain PMMA and 1,10-phenanthroline in different hybrid systems present different microstructure and luminescence behavior.