Fabrication of Eu doped CdO [Al/Eu-nCdO/p-Si/Al] photodiodes by perfume atomizer based spray technique for opto-electronic applications

Science.gov (United States)

Ravikumar, M.; Ganesh, V.; Shkir, Mohd; Chandramohan, R.; Arun Kumar, K. Deva; Valanarasu, S.; Kathalingam, A.; AlFaify, S.

2018-05-01

In this study, thin films of cadmium oxide (CdO) with different concentrations (0, 1, 3, and 5 wt%) of Eu doping were deposited onto Si and glass substrates by a novel and facile spray technique using simple perfume atomizer for the first time. Prepared films were characterized for structural, morphological, optical properties and the photo diode studies, using X-ray diffraction, scanning electron microscope, UV-Vis spectrophotometer, Isbnd V characteristics, and fundamental parameters are reported. All the prepared Eu:CdO films exhibit cubic structure. The preferential orientation is along (200) plane. Scanning electron microscopy study indicates the growth of smooth and pin-hole free films with clusters of homogeneous grains. The values of band gap energy are found to be varying from 2.42 to 2.33 eV for various Eu doping concentration from 0 to 5 wt%. EDAX studies revealed the presence of Eu, Cd and O elements without any other impurities. FTIR spectra showed a peak at 575 cm-1 confirming the stretching mode of Cdsbnd O. The resistivity (ρ), high carrier concentration (n) and carrier mobility (μ) for 3 wt% CdO thin film are found to be 0.452 × 10-3(Ω.cm), 17.82 × 1020 cm-3 and 7.757 cm2/V, respectively. Current-voltage measurements on the fabricated nanostructured Al/Eu-nCdO/p-Si/Al heterojunction device showed a non-linear electric characteristics indicating diode like behaviour.

Structural and luminescence studies of Eu3+: TeO2sbnd B2O3sbnd AOsbnd AF2 (A = Pb, Ba, Zn, Cd, Sr) glasses

Science.gov (United States)

Selvi, S.; Marimuthu, K.; Muralidharan, G.

2017-09-01

Eu3+ doped oxyfluoro boro-tellurite (TBXFE) with molar composition 29 TeO2sbnd 30B2O3sbnd 20AOsbnd 20AF2sbnd 1Eu2O3 (where A = Pb, Ba, Zn, Cd, Sr) glasses were prepared and investigated by XRD, FTIR, UV-Vis-NIR, luminescence and decay measurements. XRD patterns confirm the glassy nature of the prepared glasses. The influence of metal ions on the structure of boro-tellurite glasses were investigated through FTIR spectra. The intra band (4f-4f) transitions of Eu3+ ions are discussed through UV-Vis-NIR absorption spectra. The covalent nature around the Eu3+ ions with ligands are discussed using the bonding parameter (δ) and nephelauxetic ratio (β). The fundamental absorption edge, direct, indirect band gap, Urbach energy and band tailing parameters are reported. A bright red emission at 616 nm corresponding to the 5D0 → 7F2 transition of Eu3+ ions could be observed in the title glasses. Judd-Ofelt parameters were estimated from the emission spectra of Eu3+ ions. The dependence of these parameters on the composition of the glass is discussed. Judd-Ofelt parameters were used to derive the radiative parameters such as transition probabilities (A, s-1), branching ratios (βR), radiative lifetime (τrad) and stimulated emission cross-section (σPE) for the 5D0 → 7FJ (J = 0, 1, 2, 3 and 4) transitions. The luminescence intensity ratio (LIR) of 5D0 → 7F2/5D0 → 7F1 transitions was estimated to analyze the local site symmetry around the Eu3+ ions in the present glasses. The chromaticity coordinates and colour purity were calculated from the emission spectra and analyzed with Commission International de I'Eclairage (CIE) 1931 diagram. The experimental lifetime of 5D0 level could be fitted to a single exponential indicating the absence of energy transfer between the Eu3+ ions in the present glasses.

Sb2S3:C/CdS p-n junction by laser irradiation

International Nuclear Information System (INIS)

Arato, A.; Cardenas, E.; Shaji, S.; O'Brien, J.J.; Liu, J.; Castillo, G. Alan; Das Roy, T.K.; Krishnan, B.

2009-01-01

In this paper, we report laser irradiated carbon doping of Sb 2 S 3 thin films and formation of a p-n junction photovoltaic structure using these films. A very thin carbon layer was evaporated on to chemical bath deposited Sb 2 S 3 thin films of approximately 0.5 μm in thickness. Sb 2 S 3 thin films were prepared from a solution containing SbCl 3 and Na 2 S 2 O 3 at 27 deg. C for 5 h and the films obtained were highly resistive. These C/Sb 2 S 3 thin films were irradiated by an expanded laser beam of diameter approximately 0.5 cm (5 W power, 532 nm Verdi laser), for 2 min at ambient atmosphere. Morphology and composition of these films were analyzed. These films showed p-type conductivity due to carbon diffusion (Sb 2 S 3 :C) by the thermal energy generated by the absorption of laser radiation. In addition, these thin films were incorporated in a photovoltaic structure Ag/Sb 2 S 3 :C/CdS/ITO/Glass. For this, CdS thin film of 50 nm in thickness was deposited on a commercially available ITO coated glass substrate from a chemical bath containing CdCl 2 , sodium citrate, NH 4 OH and thiourea at 70 deg. C . On the CdS film, Sb 2 S 3 /C layers were deposited. This multilayer structure was subjected to the laser irradiation, C/Sb 2 S 3 side facing the beam. The p-n junction formed by p-Sb 2 S 3 :C and n-type CdS showed V oc = 500 mV and J sc = 0.5 mA/cm 2 under illumination by a tungsten halogen lamp. This work opens up a new method to produce solar cell structures by laser assisted material processing

Effect of structural packing on the luminescence properties in tungsten bronze compounds M{sub 2}KNb{sub 5}O{sub 15} (M=Ca, Sr, Ba)

Energy Technology Data Exchange (ETDEWEB)

Yin Xin; Shi Liu [State Key Laboratory of High Performance Ceramics and Superfine Microstructures and CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Wei Ang, E-mail: iamawei@njupt.edu.cn [Key Laboratory for Organic Electronics and Information Displays, 9 Wenyuan Road, Nanjing 210046 (China); Wan Dongyun; Wang Yaoming [State Key Laboratory of High Performance Ceramics and Superfine Microstructures and CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Huang Fuqiang, E-mail: huangfq@mail.sic.ac.cn [State Key Laboratory of High Performance Ceramics and Superfine Microstructures and CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China)

2012-08-15

Tungsten bronze compounds M{sub 2}KNb{sub 5}O{sub 15} (M=Ca, Sr, Ba) were successfully synthesized, and the luminescence properties were investigated. Among the three compounds, Ca{sub 2}KNb{sub 5}O{sub 15} showed an obviously broad band of host luminescence at 460 nm with exciting at 269 nm. By doping Eu{sup 3+} into the M sites, Ca{sub 2}KNb{sub 5}O{sub 15}:Eu{sup 3+} displayed strong red emission from Eu{sup 3+} ions characteristic transitions, nearly four times higher than Sr{sub 2}KNb{sub 5}O{sub 15}:Eu{sup 3+} and seven times higher than Ba{sub 2}KNb{sub 5}O{sub 15}:Eu{sup 3+}. Crystal packing factor (PF) was introduced to account for this luminescence difference, lower PF being correlated to higher luminescence intensity for perovskite-related structure. Both the as-prepared compounds and the literature examples were proved to fit this correlation. This can be explained through the influence of the structural packing on the environment distortion and crystal field splitting of the doping site. - Graphical abstract: Tungsten bronze compounds M{sub 2}KNb{sub 5}O{sub 15} (M=Ca, Sr, Ba) show the dependence of luminescence properties on structural packing, among which Ca{sub 2}KNb{sub 5}O{sub 15} has the superior luminescence. Highlights: Black-Right-Pointing-Pointer Tungsten bronze compounds were synthesized by solid state reaction. Black-Right-Pointing-Pointer Ca{sub 2}KNb{sub 5}O{sub 15} displayed remarkably blue host luminescence. Black-Right-Pointing-Pointer Ca{sub 2}KNb{sub 5}O{sub 15}:Eu{sup 3+} showed more intense red emission than M{sub 2}KNb{sub 5}O{sub 15}:Eu{sup 3+} (M=Sr, Ba). Black-Right-Pointing-Pointer The relationship between crystal packing factor and luminescence was obtained.

Rietveld refinement of the orthorhombic Pbca structures of Rb2CdSi5O12, Cs2MnSiO5O12, Cs2CoSi5O12 and Cs2NiSi5O12 leucites by synchrotron X-ray powder diffraction

International Nuclear Information System (INIS)

Bell, A.M.T.; Henderson, C.M.B.

1996-01-01

Analysis of high-resolution synchrotron X-ray powder diffraction patterns for hydrothermally synthesized Rb 2 CdSi 5 O 12 and Cs 2 MnSi 5 O 12 leucite analogues, and dry-synthesized Cs 2 CoSi 5 O 12 and Cs 2 NiSi 5 O 12 leucite analogues showed that they have an orthorhombic Pbca structure. The structures have been refined by the Rietveld method, showing that the tetrahedrally coordinated atoms (Si, Cd, Mn, Co and Ni) are ordered on separate sites. The Cs 2 MnSi 5 O 12 , Cs 2 CoSi 5 O 12 and Cs 2 NiSi 5 O 12 leucite samples are unusual in containing SiO 4 tetrahedra which are more distorted, on average, than the larger MnO 4 , CoO 4 and NiO 4 tetrahedra. The JCPDS file numbers for Rb 2 CdSi 5 O 12 , Cs 2 MnSi 5 O 12 and Cs 2 CoSi 5 O 12 are 46-1491, 46-1492 and 46-1493, respectively. (orig.)

A highly triflated rare-earth ion in [Eu(O_3SCF_3)_8]"5"-

International Nuclear Information System (INIS)

Bruns, Joern; Kluener, Thorsten; Kraeuter, Jessica; Wickleder, Mathias S.; Krueger, Sascha; Adlung, Matthias; Wickleder, Claudia; Niehaus, Oliver; Poettgen, Rainer

2015-01-01

The reaction of Eu_2O_3 with fuming nitric acid, trifluormethanesulfonic acid, and its anhydride in torch-sealed glass ampoules at 120 C gave the europium compound (NO)_5[Eu(O_3SCF_3)_8] (orthorhombic, Fddd, Z=16, a=1932.69(4), b=2878.44(7), c=2955.12(7) pm, V=16439.7(7) Aa"3). The compound exhibits the [Eu(O_3SCF_3)_8]"5"- anion showing for the first time a lanthanide ion that is exclusively coordinated by eight triflate anions. The anion has been further investigated by DFT calculations, which also allowed clear assignment of the vibrational spectra. Moreover, magnetochemical and luminescence measurements gave additional insight into the properties of this complex. The luminescence spectra revealed that the Eu"3"+ ions are in a pseudo D_4_d symmetric environment. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Synthesis and crystal structure of Cd2SbBr2

International Nuclear Information System (INIS)

Reshetova, L.N.; Shevel'kov, A.V.; Popovkin, B.A.

1999-01-01

A new cadmium antimonidobromide, i.e. Cd 2 SbBr 2 , has been synthesized by the standard ampoule method. The compound is crystallized in monoclinic system of sp. gr. P2 1 :a=8.244 (1), b=9.920(1), c=8.492(1) A, Β=116.80(1) deg. Binuclear anions of Sb 2 4- (Sb-Sb 2.78 A), octahedrically surrounded by six cadmium atoms, are a basic specific feature of the structure. Octahedrons of Sb 2 Cd 6 , by collectivizing the equatorial vertices. form layers, the alternation mode of which is similar to the one described for cadmium and mercury arsenidochlorides

Eu3+-doped (Y0.5La0.5)2O3: new nanophosphor with the bixbyite cubic structure

Science.gov (United States)

Đorđević, Vesna; Nikolić, Marko G.; Bartova, Barbora; Krsmanović, Radenka M.; Antić, Željka; Dramićanin, Miroslav D.

2013-01-01

New red sesquioxide phosphor, Eu3+-doped (Y0.5La0.5)2O3, was synthesized in the form of nanocrystalline powder with excellent structural ordering in cubic bixbyite-type, and with nanoparticle sizes ranging between 10 and 20 nm. Photoluminescence measurements show strong, Eu3+ characteristic, red emission ( x = 0.66 and y = 0.34 CIE color coordinates) with an average 5D0 emission lifetime of about 1.3 ms. Maximum splitting of the 7F1 manifold of the Eu3+ ion emission behaves in a way directly proportional to the crystal field strength parameter, and experimental results show perfect agreement with theoretical values for pure cubic sesquioxides. This could be used as an indicator of complete dissolution of Y2O3 and La2O3, showing that (Y0.5La0.5)2O3:Eu3+ behaves as a new bixbyite structure oxide, M2O3, where M acts as an ion having average ionic radius of constituting Y3+ and La3+. Emission properties of this new phosphor were documented with detailed assignments of Eu3+ energy levels at 10 K and at room temperature. Second order crystal field parameters were found to be B 20 = -66 cm-1 and B 22 = -665 cm-1 at 10 K and B 20 = -78 cm-1 and B 22 = -602 cm-1 at room temperature, while for the crystal field strength the value of 1495 cm-1 was calculated at 10 K and 1355 cm-1 at room temperature.

(2,4-Dioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylato-κ2O4,O5(4-oxido-2-oxo-1,2-dihydropyrimidine-5-carboxylato-κ2O4,O5bis(1,10-phenanthroline-κ2N,N′yttrium(III dihydrate

Directory of Open Access Journals (Sweden)

Zilu Chen

2008-09-01

Full Text Available In the title compound, [Y(C5H2N2O4(C5H3N2O4(C12H8N22]·2H2O, the YIII ion lies on a twofold rotation axis and exhibits a distorted square-antiprismatic coordination geometry. It is chelated by two 1,10-phenanthroline ligands, a 2,4-dioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate monoanion and a 4-oxido-2-oxo-1,2-dihydropyrimidine-5-carboxylate dianion. The H atom involved in an N—H...N hydrogen bond between the 1,2-dihydropyrimidine units has half occupancy and is disordered around a twofold rotation axis.

Sb{sub 2}S{sub 3}:C/CdS p-n junction by laser irradiation

Energy Technology Data Exchange (ETDEWEB)

Arato, A. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia-Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico); Cardenas, E. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Shaji, S. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia-Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico); O' Brien, J.J.; Liu, J. [Center for Nanoscience, University of Missouri-St. Louis, One University Boulevard, St. Louis, Missouri-63121 (United States); Department of Chemistry and Biochemistry, University of Missouri-St. Louis, One University Boulevard, St. Louis, Missouri-63121 (United States); Castillo, G. Alan; Das Roy, T.K. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Krishnan, B. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia-Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico)], E-mail: bkrishnan@fime.uanl.mx

2009-02-02

In this paper, we report laser irradiated carbon doping of Sb{sub 2}S{sub 3} thin films and formation of a p-n junction photovoltaic structure using these films. A very thin carbon layer was evaporated on to chemical bath deposited Sb{sub 2}S{sub 3} thin films of approximately 0.5 {mu}m in thickness. Sb{sub 2}S{sub 3} thin films were prepared from a solution containing SbCl{sub 3} and Na{sub 2}S{sub 2}O{sub 3} at 27 deg. C for 5 h and the films obtained were highly resistive. These C/Sb{sub 2}S{sub 3} thin films were irradiated by an expanded laser beam of diameter approximately 0.5 cm (5 W power, 532 nm Verdi laser), for 2 min at ambient atmosphere. Morphology and composition of these films were analyzed. These films showed p-type conductivity due to carbon diffusion (Sb{sub 2} S{sub 3}:C) by the thermal energy generated by the absorption of laser radiation. In addition, these thin films were incorporated in a photovoltaic structure Ag/Sb{sub 2}S{sub 3}:C/CdS/ITO/Glass. For this, CdS thin film of 50 nm in thickness was deposited on a commercially available ITO coated glass substrate from a chemical bath containing CdCl{sub 2}, sodium citrate, NH{sub 4}OH and thiourea at 70 deg. C . On the CdS film, Sb{sub 2}S{sub 3}/C layers were deposited. This multilayer structure was subjected to the laser irradiation, C/Sb{sub 2}S{sub 3} side facing the beam. The p-n junction formed by p-Sb{sub 2}S{sub 3}:C and n-type CdS showed V{sub oc} = 500 mV and J{sub sc} = 0.5 mA/cm{sup 2} under illumination by a tungsten halogen lamp. This work opens up a new method to produce solar cell structures by laser assisted material processing.

Synthesis, crystal structure, and magnetic properties of novel 2D kagome materials RE{sub 3}Sb{sub 3}Mg{sub 2}O{sub 14} (RE = La, Pr, Sm, Eu, Tb, Ho): Comparison to RE{sub 3}Sb{sub 3}Zn{sub 2}O{sub 14} family

Energy Technology Data Exchange (ETDEWEB)

Sanders, M.B.; Baroudi, K.M.; Krizan, J.W.; Mukadam, O.A.; Cava, R.J. [Department of Chemistry, Princeton University, Princeton, NJ (United States)

2016-10-15

The crystal structures and magnetic properties of RE{sub 3}Sb{sub 3}Mg{sub 2}O{sub 14} (RE = La, Pr, Sm, Eu, Tb, Ho) with a perfect kagome lattice are presented and compared to RE{sub 3}Sb{sub 3}Zn{sub 2}O{sub 14}. Rietveld structure refinements were performed using X-ray diffraction data, indicating that the layered compounds are fully structurally ordered. The compounds crystallize in a rhombohedral supercell of the cubic pyrochlore structure, in the space group R-3m. Magnetic susceptibility measurements show no signs of magnetic ordering above 2 K. The RE{sub 3}Sb{sub 3}Mg{sub 2}O{sub 14} family is similar to that of RE{sub 3}Sb{sub 3}Zn{sub 2}O{sub 14}; however, the series reported here features a fully ordered distribution of cations in both the nonmagnetic antimony and magnetic rare earth kagome lattices. Unlike the offsite disorder that Zn{sup 2+} experiences in RE{sub 3}Sb{sub 3}Zn{sub 2}O{sub 14}, the magnesium sites in RE{sub 3}Sb{sub 3}Mg{sub 2}O{sub 14} are completely ordered. Here we compare the magnetic properties in both series of kagome compounds to determine how significant Zn{sup 2+}'s positional ordering is within this structure type. The compounds reported here appear to be relatively defect-free and are therefore model systems for investigating magnetic frustration on an ideal 2D rare earth kagome lattice. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Structural and optical properties of Ta{sub 2}O{sub 5}:Eu{sup 3+}: Mg{sup 2+} or Ca{sup 2+} phosphor prepared by molten salt method

Energy Technology Data Exchange (ETDEWEB)

Verma, Naveen, E-mail: vermanaveen17@gmail.com; Singh, Krishan Chander; Jindal, Jitender [Department of chemistry, Maharshi Dayanand University, Rohtak-124001 – India (India); Mari, Bernabe; Mollar, Miguel; Manjón, F. J. [Institut de Disseny per la Fabricació Automatitzada - Departament de Física Aplicada, Universitat Politècnica de València, Camí de Vera s/n, 46022 València (Spain); Rana, Ravi [Department of Chemistry, SGT University, Gurgaon (India); Pereira, A. L. J. [Universitat Politècnica de València, 46022 València (Spain)

2016-04-13

Ta{sub 2}O{sub 5}:Eu{sup 3+}: Mg{sup 2+} or Ca{sup 2+} phosphor materials were prepared by molten salt method using KCl as flux. The X-ray diffraction (XRD) patterns illustrated that the well crystallized Ta{sub 2}O{sub 5}:Eu{sup 3+}: Mg{sup 2+} or Ca{sup 2+} were formed in the presence of flux under reduced temperature (800 °C) in contrast to conventional solid state method (1200-1500 °C). Scanning electron microscope (SEM) images indicate the achievement of well dispersed particles (hexagonal tablet and rod-like structures). Meanwhile, the photo-luminescent studies demonstrated that Ta{sub 2}O{sub 5} is an efficient host to sensitize europium red emissions. The addition of Mg{sup 2+} or Ca{sup 2+} as co-dopant enhanced the luminescent intensity of Ta{sub 2}O{sub 5}: Eu{sup 3+} compound.

Photoreduction of Carbon Dioxide to Methane Over Sb1.5Sn8.5-x Ti x O19.0 with High Conductivity.

Science.gov (United States)

Do, Jeong Yeon; Kwak, Byeong Sub; Kang, Misook

2018-09-01

In order to enhance the photoreduction of CO2 to CH4, a new type of photocatalyst, Sb1.5Sn8.5-xTixO19.0, with high conductivity and low bandgap was developed by partially incorporating Ti into the framework of Sb1.5Sn8.5O19.0 (antimony-doped tin oxide, ATO) using a controlled hydrothermal method. XRD and TEM analyses indicated that the Sb1.5Sn8.5-xTixO19.0 particles exhibited a tetragonal crystal structure and were approximately 20 nm in size. Furthermore, the bandgap and conductivity of these materials increased with increasing Ti content. A study of the photoreduction of CO2 with H2O revealed a remarkable increase in the generation of CH4 over the Sb1.5Sn8.5-xTixO19.0 catalysts. In particular, CH4 generation was the highest when Sb1.5Sn8.5Ti1.0O19.0 was used as the photocatalyst, and was three-fold higher than that achieved by using anatase TiO2. Photoluminescence studies showed that the enhanced photocatalytic activity of the Sb1.5Sn8.5-xTixO19.0 materials could be attributed to the interfacial transfer of photogenerated charges, which led to an effective charge separation and inhibition of the recombination of photogenerated electron-hole (e-/h+) pairs.

Thermal decomposition of RE(C2H5CO2)3·H2O (RE = Dy, Tb, Gd, Eu and Sm)

DEFF Research Database (Denmark)

Grivel, Jean-Claude

2014-01-01

The thermal decomposition of Dy(III), Tb(III), Gd(III), Eu(III), and Sm(III) propionate monohydrates was studied in argon by means of simultaneous differential thermal analysis and thermogravimetry, infrared-spectroscopy, X-ray diffraction, and optical microscopy. After dehydration, which takes......, an intermediate stage involving a RE2O(C2H5CO2)4 composition was evidenced in the case of the Eu- and Sm-propionates. For all compounds, further decomposition of RE2O2CO3 into the corresponding sesquioxides (RE2O3) is accompanied by the release of CO2. The thermal decomposition of Dy- and Tb-propionates occurs...

Luminescence of Eu:Y3Al5O12, Eu:Lu3Al5O12, and Eu:GdAlO3 Nanocrystals Synthesized by Solution Combustion

Science.gov (United States)

Vilejshikova, E. V.; Khort, A. A.; Podbolotov, K. B.; Loiko, P. A.; Shimanski, V. I.; Shashkov, S. N.; Yumashev, K. V.

2017-11-01

Nanocrystals of rare-earth garnets Y3Al5O12 and Lu3Al5O12 and perovskite GdAlO3 highly doped (10-20 at%) with Eu3+ are synthesized by the solution combustion technique and subsequent annealing in air at 800 and 1300oC. Their structure, morphology, and phase composition are studied. These materials exhibit intense red luminescence under UV excitation. Eu:GdAlO3 luminescence has CIE 1931 color coordinates (0.632, 0.368); dominant wavelength, 599.6 nm; and color purity, >99%. Judd-Ofelt parameters, luminescence branching ratios, and lifetimes of the Eu3+ 5D0 state are determined. The luminescence quantum yield for Eu:GdAlO3 (10 at%) reaches 74% with a lifetime of 1.4 ms for the 5D0 state. The synthesized materials are promising for red ceramic phosphors.

trans-Diaquabis(1,1,1,5,5,5-hexafluoropentane-2,4-dionato-κ2O,O′cobalt(II dihydrate

Directory of Open Access Journals (Sweden)

Takumi Tominaga

2017-01-01

Full Text Available The CoII atom in the mononuclear title compound, [Co(C5HF6O22(H2O2]·2H2O, is situated on an inversion centre and exhibits a slightly distorted octahedral coordination sphere. In the crystal, molecules are arranged in layers parallel to (100, held together by O—H...O and O—H...F hydrogen bonds.

Formation of high-conductivity regions in SnO2-AOx (A - Ti4+, Zr4+, Sb3+, Sb5+) films exposed to ultraviolet radiation of H2

International Nuclear Information System (INIS)

Postovalova, G.G.; Roginskaya, Yu.E.; Zav'yalov, S.A.; Galyamov, B.Sh.; Klimasenko, N.L.

2000-01-01

Composition, structure and electron properties of SnO 2 films doped by Ti, Zr and Sb oxides were studied. The doped SnO 2 films were determined to contain nano-regions of SnO 2 base crystalline solid solutions and amorphous SnO 2 containing Sn 2+ or Sb 3+ ions and residing at the surface of crystallites or between them. These composition and structure peculiarities affect essentially both electron structure and electrical properties of films. Localized 5s-states of the conductivity range diffused boundary of amorphous SnO 2 partially filled with 5s-electrons of Sn 2+ or Sb 3+ ions serving as traps capture free electrons in the crystalline ranges and motivate high resistance of films [ru

Syntheses and luminescence study for La{sub 1−x}Eu{sub x}[B{sub 5}O{sub 8}(OH){sub 2}]·1.5H{sub 2}O (0≤x≤0.40) and the dehydrated products β-La{sub 1−x}Eu{sub x}B{sub 5}O{sub 9} (0≤x≤0.15)

Energy Technology Data Exchange (ETDEWEB)

Sun, Xiaorui; Zhou, Zhengyang; Yang, Haixia; Gao, Wenliang; Cong, Rihong, E-mail: congrihong@cqu.edu.cn; Yang, Tao, E-mail: taoyang@cqu.edu.cn

2016-05-15

La{sub 1−x}Eu{sub x}[B{sub 5}O{sub 8}(OH){sub 2}]·1.5H{sub 2}O with the Eu{sup 3+}-doping upper limit of 40 atom% were synthesized hydrothermally. Thereafter, thermal treatments at 710 °C were applied to obtain β-La{sub 1−x}Eu{sub x}B{sub 5}O{sub 9}. The solid solution range is even narrower, i.e. 0≤x≤0.15, due to the mismatch between La{sup 3+} and Eu{sup 3+}. The host borate system shows a typical concentration quenching effect at x=0.20 under CT excitation, and this is postponed to x=0.30 under the f−f excitation. β-La{sub 1−x}Eu{sub x}B{sub 5}O{sub 9} shows a very intense absorption of charge transfer, and gives strong red emissions at 615 nm with large R/O ratios (1.9–2.4). The saturation effect appears at x=0.11, which is probably due to the lattice distortion. Eu{sup 3+} luminescence was applied as the structural probe to study the local coordination environment change during the dehydration and re-crystallization processes of La{sub 0.93}Eu{sub 0.07}[B{sub 5}O{sub 8}(OH){sub 2}]·1.5H{sub 2}O. - Highlights: • La{sub 1−x}Eu{sub x}[B{sub 5}O{sub 8}(OH){sub 2}]·1.5H{sub 2}O (0≤x≤0.40) were prepared by hydrothermal method. • The Eu{sup 3+}-doping limit in β-La{sub 1−x}Eu{sub x}B{sub 5}O{sub 9} is 15 atom% proved by powder XRD. • La{sub 1−x}Eu{sub x}[B{sub 5}O{sub 8}(OH){sub 2}]·1.5H{sub 2}O show relatively weaker red emissions. • β-La{sub 1−x}Eu{sub x}B{sub 5}O{sub 9} shows an intense CT absorption together with strong red emissions. • Eu{sup 3+} luminescence was studied when annealing La{sub 0.93}Eu{sub 0.07}[B{sub 5}O{sub 8}(OH){sub 2}]·1.5H{sub 2}O.

Crossrelaxations and non-radiative energy transfer from (4G5/2) Sm3+ → (5D0) Eu3+: B2O3–ZnO glasses

International Nuclear Information System (INIS)

Naresh, V.; Rudramadevi, B.H.; Buddhudu, S.

2015-01-01

Graphical abstract: The energy transfer process occurring from Sm 3+ to Eu 3+ in B 2 O 3 –ZnO (BZn) glasses is analyzed. Based on the Foster–Dexter theory, the possibility of energy transfer between Sm 3+ and Eu 3+ has been demonstrated from the spectral overlap of Eu 3+ absorption and Sm 3+ emission, photoluminescence spectra, energy level diagram and lifetime measurements. The energy transfer mechanism in (Sm 3+ + Eu 3+ ) co-doped glass is governed by dipole–dipole interaction. - Highlights: • Spectroscopic properties of individually doped Sm 3+ , Eu 3+ & co-doped (Sm 3+ + Eu 3+ ) in BZn glasses were studied separately. • The effect of Eu 3+ concentration on luminescence properties is explained from cross-relaxations. • Energy transfer from Sm 3+ ( 4 G 5/2 ) to Eu 3+ ( 5 D 0 ) has been explained from Foster–Dexter theory. • Dipole–dipole mechanism governs the energy transfer from Sm 3+ to Eu 3+ . - Abstract: The present paper reports on the results concerning to photoluminescence features of Eu 3+ , Sm 3+ ions and energy transfer process occurring from Sm 3+ to Eu 3+ doped in 45 B 2 O 3 –55 ZnO (BZn) glasses prepared by melt quenching technique. Luminescence quenching as a function of Eu 3+ concentration in BZn glasses has been discussed. Among the studied concentrations, 0.5 mol% of Eu 3+ is optimized because it has exhibited red emission transition 5 D 0 → 7 F 2 . With regard to Sm 3+ glasses, orange emission at 602 nm ( 4 G 5/2 → 6 H 7/2 ) has been noticed on exciting with λ exci = 403 nm. Based on the Foster–Dexter theory, the possibility of energy transfer between Sm 3+ and Eu 3+ has been explained from the spectral overlap of Eu 3+ absorption and Sm 3+ emission. The optimized concentration 0.5 mol% of Eu 3+ is co-doped with Sm 3+ in various concentrations ranging from 0.1 to 1.5 mol% inorder to study the sensitization effect of Sm 3+ on Eu 3+ luminescence. The results have revealed that with the addition of Sm 3+ to Eu 3+ : BZn

(1−x)[(K$_{0.5}$Na$_{0.5}$)NbO$_3$–LiSbO$_3

Indian Academy of Sciences (India)

Lead-free piezoelectric ceramics ( 1 − x ) [0.95(K 0.5 Na 0.5 )NbO 3 –0.05LiSbO 3 ]– x BiFe 0.8 Co 0.2 O 3 (KNN–LS– x BFC) were prepared by a conventional sintering technique. The effect of BFC content on the structure, piezoelectricand electrical properties of KNN–LS ceramics was investigated. The results reveal that ...

Study of 5f electron based filled skutterudite compound EuFe{sub 4}Sb{sub 12}, a thermoelectric (TE) material: FP-LAPW method

Energy Technology Data Exchange (ETDEWEB)

Shankar, A., E-mail: amitshan2009@gmail.com [Department of Physics, Mizoram University, Aizawl 796004 (India); Rai, D.P., E-mail: dibyaprakashrai@gmail.com [Beijing Computational Science Research Center, 3 Heqing Road, Beijing 100084 (China); Khenata, R. [Laboratoire de Physique Quantique et de Modlisation Mathmatique (LPQ3M), Dpartement de Technologie, Universit de Mascara, 29000 Mascara (Algeria); Maibam, J. [Department of Physics, Assam University, Silchar 788011 (India); Sandeep, E-mail: sndp.chettri@gmail.com [Department of Physics, Mizoram University, Aizawl 796004 (India); Thapa, R.K., E-mail: r.k.thapa@gmail.com [Department of Physics, Mizoram University, Aizawl 796004 (India)

2015-01-15

Highlights: • The compound EuFe{sub 4}Sb{sub 12} shows a semi-metallic behavior with pseudo gap. • The inherent dense band near E{sub F} facilitate the charge carriers. • The magnetic moment within LSDA and mBJ are underestimated. • The inclusion of onsite Coulomb repulsion (U) in LSDA has improved the result. • The results obtained from LSDA + U are consistent with the experimental data. - Abstract: We have studied the elastic, electronic and magnetic properties along with the thermoelectric properties of an undoped filled skutterudite EuFe{sub 4}Sb{sub 12} using full-potential linearized augmented plane wave (FP-LAPW) method. The LSDA, LSDA + U and a new exchange-correlation functional called modified Becke Johnson (mBJ) potential based on density functional theory (DFT) were used for studying material properties. The Eu-f and Fe-d are strongly correlated elements thus the inclusion of Coulomb repulsion (U) expected to give an exact ground state properties. The exchange-splitting of Eu-4f states were analyzed to explain the ferromagnetic behavior of EuFe{sub 4}Sb{sub 12} (half-metallic behavior). The numerical values of isotropic elastic parameters and related properties are estimated in the framework of the Voigt–Reuss–Hill approximation. The calculation of thermal transport properties at various temperature shows the high value of Seebeck coefficient and figure of merit (ZT) = 0.25 at room temperature in consistent to the experimental results.

Green-emissive transparent BaSi 2O 5:Eu 2 + film phosphor on quartz glass created by a sputtering thermal diffusion process

Science.gov (United States)

Seo, K. I.; Park, J. H.; Kim, J. S.; Na, Y. H.; Choi, J. C.; Bae, J. S.

2009-10-01

Eu 2+-doped BaSi 2O 5 film phosphors on quartz substrates are fabricated by radio-frequency magnetron sputtering thermal diffusion. The BaSi 2O 5: Eu 2+ phosphor crystals have some preferred orientations that are lattice-spacing matched with the crystallized β- SiO 2 crystals, and they show pore and grain boundary-free morphology with a rod-like shape fused into the crystallized β- SiO 2 crystals. The BaSi 2O 5: Eu 2+ film phosphor has a high transparency, with a transmittance of about 30% in visible light. The BaSi 2O 5: Eu 2+ film phosphor shows 510 nm green emission from the f-d transition of the Eu 2+ ions, and in particular the best sample shows a green photoluminescence brightness of about 5% of a BaSi 2O 5: Eu 2+ powder phosphor screen. These excellences in optical properties can be explained by less optical scattering at pores or grain boundaries, and less reflection at the continuously index-changed interface.

Ion-irradiation resistance of the orthorhombic Ln_2TiO_5 (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb and Dy) series

International Nuclear Information System (INIS)

Aughterson, Robert D.; Lumpkin, Gregory R.; Ionescu, Mihail; Reyes, Massey de los; Gault, Baptiste; Whittle, Karl R.; Smith, Katherine L.; Cairney, Julie M.

2015-01-01

The response of Ln_2TiO_5 (where Ln is a lanthanide) compounds exposed to high-energy ions was used to test their suitability for nuclear-based applications, under two different but complementary conditions. Eight samples with nominal stoichiometry Ln_2TiO_5 (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb and Dy), of orthorhombic (Pnma) structure were irradiated, at various temperatures, with 1 MeV Kr"2"+ ions in-situ within a transmission electron microscope. In each case, the fluence was increased until a phase transition from crystalline to amorphous was observed, termed critical dose D_c. At certain elevated temperatures, the crystallinity was maintained irrespective of fluence. The critical temperature for maintaining crystallinity, T_c, varied non-uniformly across the series. The T_c was consistently high for La, Pr, Nd and Sm_2TiO_5 before sequential improvement from Eu to Dy_2TiO_5 with T_c's dropping from 974 K to 712 K. In addition, bulk Dy_2TiO_5 was irradiated with 12 MeV Au"+ ions at 300 K, 723 K and 823 K and monitored via grazing-incidence X-ray diffraction (GIXRD). At 300 K, only amorphisation is observed, with no transition to other structures, whilst at higher temperatures, specimens retained their original structure. The improved radiation tolerance of compounds containing smaller lanthanides has previously been attributed to their ability to form radiation-induced phase transitions. No such transitions were observed here. - Highlights: • First ion-irradiation studies on a number of novel compounds including Pr_2TiO_5, Eu_2TiO_5 and Tb_2TiO_5. • Systematic in-situ ion-irradiation study of almost complete Ln_2TiO_5 series (Ln = lanthanides) with orthorhombic crystal structure type. • The first grazing incidence study of bulk irradiated Dy_2TiO_5 looking for irradiation induced phase transition.

Unique dielectric features of a ceramic-semiconductor nanocomposite MgNb2O6 + 0.25Zn0.5Cd0.5S

Science.gov (United States)

Pukazhselvan, D.; Selvaraj, Nivas Babu; Bdikin, Igor; Saravanan, R. Sakthi Sudar; Jakka, Suresh Kumar; Soares, M. J.; Fagg, Duncan Paul

2017-12-01

The present communication deals with the optical/dielectric characteristics of MgNb2O6 + 0.25Zn0.5Cd0.5S nanocomposite (10-30 nm) mixture. Zn0.5Cd0.5S (size ∼10 nm) was synthesized by microwave assisted solvo-thermal method. Monophase magnesium niobate (MN) nanoparticles (10-20 nm) were synthesized in a single step by mechanochemical treatment of MgO + Nb2O5 under dry N2 atmosphere. The nanocomposite, MgNb2O6 + 0.25Zn0.5Cd0.5S, was prepared by mechanical admixing of MgNb2O6 and Zn0.5Cd0.5S taken in 4:1 molar ratio. The photoluminescence study shows violet, yellow and orange-red emissions by the MgNb2O6 + 0.25Zn0.5Cd0.5S composite. The observed dielectric constant value (ε) for MgNb2O6 + 0.25Zn0.5Cd0.5S is only 4.7, which is ∼5 times smaller than the ε value of MgNb2O6 while a dielectric loss for the composite being closer to zero ensures promising commercial applications.

Bi∼3.785Cd∼3.575Cu∼1.5(PO4)3.5O5.5, a new arrangement of double (n=2) and triple (n=3) [M4Bi2n-2O2n]x+ polycationic ribbons in the bismuth-transition metal oxy-phosphate series

International Nuclear Information System (INIS)

Colmont, Marie; Huve, Marielle; Abraham, Francis; Mentre, Olivier

2004-01-01

This work is dedicated to investigation of new disordered bismuth-containing oxy-phosphates compounds with an original structure type. As previously observed in this series, they are formed of [M 4 Bi 2n-2 O 2n ] x+ polycationic ribbons of width n O(Bi,M) 4 tetrahedra, surrounded by PO 4 groups. In the new crystal structure type, double (=D), triple (=T) and tunnels (=t) alternate along a common axis obeying the TtDtTtDt/TTtTTt sequence in respect to a nomenclature previously described and recalled in this work. The existence this new polymorph has first been detected by electron diffraction in a multi-phased sample. Then, the crystal structure type, i.e., the TtDtTtDt/TTtTTt sequence, has been deduced from HREM images help to a contrast-interpreting code available for these series of polycations-formed compounds. The subsequent compounds formulation leads to a number of new materials that verify the general formula: [Bi 2 (Bi,M) 4 O 4 ] 2 [Bi 4 (Bi,M) 4 O 6 ] 6 (PO 4 ) 28 M x , with x= 2+ , Cd 2+ cations. Single crystals of the nominal [O6Bi 4.57 Cd 3.43 ] 4 +8.57 [O 6 Bi 4 Cd 4 ] 2 +8 [O 4 Bi 2 Cd 3.56 Cu 0.44 ] 2 +6 (PO 4 ) 28 Cu 10.86 have been prepared in a further stage and confirms the predicted crystal structure, Bi ∼3.785 Cd ∼3.575 Cu ∼1.5 (PO 4 ) 3.5 O 5.5 , a=11.506(8)A, b=5.416(4)A, c=53.94 (4)A, β=90.10(1) o , RF=0.0835, RwF=0.0993, SG=A2/m, Z=8. As already observed for other elements of this family such as Bi ∼1.2 M ∼1.2 O 1.5 (PO 4 ), Bi ∼6.2 Cu ∼6.2 O 8 (PO 4 ) 5 or Bi ∼3 Cd ∼3.72 M ∼1.28 O 5 (PO 4 ) 3 (M=Cu, Co, Zn), this compound shows an additional example of PO 4 disorder due to the presence of mixed Bi 3+ /M 2+ sites at the edges of ribbons. The origin and consequence of this so-called disorder mostly occurring on PO 4 configurations is intensively discussed and has been characterized by infrared spectroscopy and by neutron diffraction on similar compounds. It is noticeable that the great number of antagonist PO 4

Photoluminescence properties of a novel red phosphor Sr{sub 3}Ga{sub 2}O{sub 5}Cl{sub 2}:Eu{sup 3+}

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhonghua; Hu, Yihua; Zhang, Shaoan; Lin, Jun [Guangdong University of Technology, School of Physics and Optoelectronic Engineering, Guangzhou (China)

2016-02-15

Eu{sup 3+}-doped Sr{sub 3}Ga{sub 2}O{sub 5}Cl{sub 2} phosphors were synthesized successfully via a two-step solid-state reaction method. Phase purity and morphology of the phosphor were confirmed by XRD and SEM techniques. In the excitation spectra of Sr{sub 3}Ga{sub 2}O{sub 5}Cl{sub 2}:Eu{sup 3+} phosphor, the broad excitation band centering at 310 nm is due to the combination of charge transfer from Eu{sup 3+}→O{sup 2-} and host absorption. And it matches well the emission wavelength from UV LEDs. Sr{sub 3}Ga{sub 2}O{sub 5}Cl{sub 2}:Eu{sup 3+} phosphors show a bright orange-red luminescence under excitation with 301 nm. However, concentration quenching of Eu{sup 3+} in Sr{sub 3}Ga{sub 2}O{sub 5}Cl{sub 2}:Eu{sup 3+} occurs at a low content of 0.07 in this work. The quenching mechanism of Sr{sub 3}Ga{sub 2}O{sub 5}Cl{sub 2}:Eu{sup 3+} was discussed in detail on the basis of the experimental results. (orig.)

Absence of ferroelectric features in Eu2BaNiO5: An anomalous case within this rare-earth family

Science.gov (United States)

Upadhyay, Sanjay Kumar; Sampathkumaran, E. V.

2018-04-01

We report the results of magnetization, heat-capacity, magnetodielectric and pyrocurrent measurements above 2 K for the compound, Eu2BaNiO5, a Haldane spin-chain compound. This compound has been known to exhibit a magnetic transition in the vicinity of 5 K from Eu and Ni, but we do not find any evidence for ferroelectricity above 2 K, in sharp contrast to the multiferroic behavior reported for other members of this Haldane spin-chain family. Instead, there is a pyrocurrent peak around 40 K, which is sensitive to the rate of change of temperature thereby providing an evidence for thermally stimulated depolarization current. Additionally, this study brings out two more features: (i) There is a dielectric anomaly in the range 75-100 K, attributable to short-range magnetic correlations, similar to the situation encountered in another spin-chain system Ca3Co2O6, and (ii) there is a sign crossover of magnetodielectric effect (MDE) with varying magnetic field well below 8 K only, with relatively negligible values of MDE above 4 K, and this observation establishes the existence of a coupling between magnetic and electric dipoles at the onset of long-range magnetic order.

White LED based on CaAl2Si2O8:Eu2+ Mn2+ phosphor and CdS/ZnS quantum dots

Science.gov (United States)

Shen, Changyu; Zhong, Chuan; Hou, Qianglong; Li, Ke

2011-02-01

Core/shell CdS/ZnS quantum dots (QDs) with the emission wavelength of 610nm, was synthesized by thermal deposition using cadmium oxide and selenium as precursors in a hot lauric acid and hexadecylamine trioctylphosphine oxide hybrid. CaAl2Si2O8:Eu2+ Mn2+ phosphor was synthesized by high-temperature solid state reaction at 1290 °C for 2 hours under the H2 reducing atmosphere, and X-ray powder diffraction analysis confirmed the formation of it. It has two emission bands peaking at 420 nm and 580nm originated from the transition 5d to 4f of Eu2+ and 4T1-6A1 of Mn2+, respectively. Blends of CaAl2Si2O8:Eu2+,Mn2+ phosphor and CdS/ZnS QDs exhibited the prominent spectral evolution with an increasing content of QDs. A hybrid white LED, which combines a blue LED with the blend of CaAl2Si2O8:Eu2+ Mn2+ phosphor and QDs with a weight ratio of 2:1, with the CIE coordinate of (0.3183, 0.3036) and CRI of 85 was obtained.

Microstructural and thermoelectric properties of p-type Te-doped Bi{sub 0.5}Sb{sub 1.5}Te{sub 3} and n-type SbI{sub 3}-doped Bi{sub 2}Te{sub 2.85}Se{sub 0.15} compounds

Energy Technology Data Exchange (ETDEWEB)

Seo, J; Park, K; Lee, C; Kim, J

1997-07-01

The p-type Te-doped Bi{sub 0.5}Sb{sub 1.5}Te{sub 3} and n-type SbI{sub 3}-doped Bi{sub 2}Te{sub 2.85}Se{sub 0.15} thermoelectric compounds were fabricated by hot pressing in the temperature range of 380 to 440 C under 200 MPa in Ar. Both the compounds were highly dense and showed high crystalline quality. The grains of the compounds were preferentially oriented and contained many dislocations through the hot pressing. The fracture path followed the transgranular cleavage planes, which are perpendicular to the c-axis. In addition, with increasing the pressing temperature, the figure of merit was increased. The highest values of figure of merit for the p- and n-type compounds, which were obtained at 420 C, were 2.69 x 10{sup {minus}3}/K and 2.35 x 10{sup {minus}3}/K, respectively.

Synthesis and characterization of YBaCu2O5-δ compound

Science.gov (United States)

Ehsandoust, A.; Sandoghchi, M.; Mokhtari, P.; Akhavan, M.

2018-05-01

YBaCu2O5 compound as one of the possible microstructures of Y3Ba5Cu8O19 has been synthesized. The X-ray diffraction analysis of this compound indicates that its formation is accompanied with the formation of YBa2Cu3O7-δ. The observed superconductivity around ∼92 K supports this. So, it seems that YBa2Cu3O7-δ is responsible for the observed superconductivity in YBaCu2O5, and this phase is not an independent superconducting phase. Consequently, the overall effect of the YBaCu2O5 formation during the Y3Ba5Cu8O19 fabrication process could be a reduction in Tc.

Optical Properties and Photoactivity of The Pigmentary TiO2 Doped with P2O5, K2O, Al2O3 and Sb2O3

International Nuclear Information System (INIS)

Glen, M; Grzmil, B

2011-01-01

The influence of the increasing content of antimony calculated to Sb 2 O 3 (0.08-0.57 mol%) with the constant amount of the other additives (calculated to P 2 O 5 , K 2 O, Al 2 O 3 ) on the optical properties and photostability of doped rutile has been investigated. The properties of the obtained TiO 2 -PKAlSb samples were compared to the commercial TiO 2 -PKAl composition. The starting material was the concentrated suspension of technical-grade hydrated titanium dioxide (HTD). The dopant agents' solutions were introduced to HTD. Prepared samples were calcined with gradually increasing process temperature. The XRD analysis was used to determine the rutile content in the TiO 2 samples. Optical properties of modified titanium dioxide have been determined spectrophotometrically by measuring the colour in the white (brightness, white tone) and grey system (relative lightening power, grey tone). Photostability was characterized by the white lead-glycerin test with UV-Vis light. It was observed that with the increasing content of antimony in rutile TiO 2 , doped with phosphates, potassium and aluminium, the brightness and grey tone were increasing but white tone decreased. The changes of the relative lightening power values were insignificant. Comparing the samples of TiO 2 -PKAlSb with the TiO 2 -PKAl composition it was observed that titanium dioxide doped with antimony had better white and grey tone. The increasing Sb 2 O 3 content in the TiO 2 caused the improvement of the photostability.

Synthesis of homogeneous Ca0.5Sr0.5FeO2.5+δ compound using a mirror furnace method

International Nuclear Information System (INIS)

Mahboub, M.S.; Zeroual, S.; Boudjada, A.

2012-01-01

Graphical abstract: X-ray diffraction pattern indexing of Ca 0.5 Sr 0.5 FeO 2.5+δ powder sample obtained by mirror furnace method after thermal treatment. Highlights: ► A homogenous compound Ca 0.5 Sr 0.5 FeO 2.5+δ has been synthesized for the first time by a mirror furnace method. ► Ca 0.5 Sr 0.5 FeO 2.5+δ powder sample is perfectly homogenous, confirmed by X-ray diffraction, Raman spectroscopy and EDS technique. ► The thermal treatment of Ca 0.5 Sr 0.5 FeO 2.5+δ powder sample can increase their average grain sizes. -- Abstract: A new synthesis method using melting zone technique via the double mirror furnace around 1600 °C is used to obtain homogenous brownmillerite compounds Ca 1−x Sr x FeO 2.5+δ in the range 0.3 ≤ x ≤ 0.7. These compounds play important role in understanding the mystery of the oxygen diffusion in the perovskite-related oxides. We have successfully solved the miscibility gap problem by synthesizing a good quality of homogenous powder samples of Ca 0.5 Sr 0.5 FeO 2.5+δ compound. Our result was confirmed by X-rays diffraction, Raman spectroscopy and energy dispersive spectroscopy analysis. Thermal treatment was also applied until 800 °C under vacuum to confirm again the homogeneity of powder samples, improve its quality and show that no decomposition or return to form Ca- and Sr-enriched microdomains takes place as a result of phase separation.

Structural, hyperfine and Raman properties of RE2FeSbO7 compounds

International Nuclear Information System (INIS)

Berndt, G.; Silva, K.L.; Ivashita, F.F.; Paesano, A.; Blanco, M.C.; Miner, E.V.P.; Carbonio, R.E.; Dantas, S.M.; Ayala, A.P.; Isnard, O.

2015-01-01

Highlights: • We prepared monophasic RE 2 FeSbO 7 pyrochlores. • RE 2 FeSbO 7 compounds were characterized regarding crystallographic, vibrational and hyperfine properties. • We find out that a site disorder takes place for the RE’s of larger ionic radii. • Lattice parameters, Raman bands and quadrupole splittings were shown to depend correlatedly on the RE ionic radius. - Abstract: Pyrochlores of the RE 2 FeSbO 7 type were synthesized by ball-milling followed by annealing in free atmosphere at high temperatures. The samples prepared were characterized by X-ray diffraction, Raman spectroscopy and 57 Fe Mössbauer spectroscopy, at room temperature. The results showed that RE 2 FeSbO 7 compounds have a cubic structure, i.e., Fd-3m (#227) space group, and that a site disorder takes place for the RE’s of larger ionic radii. Lattice parameters, Raman bands and quadrupole splittings were shown to depend correlatedly on the RE ionic radius. This behavior is discussed in terms of the pyrochlore crystallographic structure

The 5s25p2 - (5s25p5d + 5s5p3 + 5s25p6s + 5s25p7s) transitions in Sb II and 5s25p - (5s5p2 + 5s2nl) transitions in Sb III

International Nuclear Information System (INIS)

Arcimowicz, B.; Joshi, Y.N.; Kaufman, V.

1989-01-01

The spectrum of antimony was photographed in the 575-2300 A region (1A 10 -10 m) using a hollow cathode and a triggered spark source. The analysis of the 5s 2 5p 2 - (5s 2 5p5d + 5s5p 3 + 5s 2 5p6s + 5s 2 5p7s) transitions in Sb II spectrum was revised and interpreted on the basis of multiconfiguration interaction calculations. Accurate wavelength measurements of Sb III lines lead to a revised ground-state 5s 2 5p 2 P interval value of 6574.5 cm -1 . (author). 15 refs., 9 tabs., 1 fig

Mixed oxides forming in CdO-OsO2 and PbO-OsO2 systems

International Nuclear Information System (INIS)

Shaplygin, I.S.; Lazarev, V.B.

1978-01-01

The formation of mixed oxides in systems CdO-OsO 2 and PbO-OsO 2 was studied by derivatography, X-ray phase analysis, and IR spectroscopy. It was established that in the system CdO-OsO 2 cubic phases of Cdsub(2)Ossub(2)Osub(6.7) and Cdsub(2)Ossub(2)Osub(7.2) with a pyrochlor-type structure, as well as new compounds with the structure of rhombic perovskite CdOsO 3 and Cd(Cdsub(0.5)Ossub(0.5))Osub(3) containing osmium in the formal degree of oxidation +4 and +6, respectively, are formed. The thermal stability of the compounds obtained was studied and their electrical properties determined

Phosphor thermometry: On the synthesis and characterisation of Y{sub 3}Al{sub 5}O{sub 12}:Eu (YAG:Eu) and YAlO{sub 3}:Eu (YAP:Eu)

Energy Technology Data Exchange (ETDEWEB)

Kissel, T. [Fachgebiet Reaktive Strömungen und Messtechnik (RSM), Center of Smart Interfaces (CSI), Technische Universität Darmstadt, Petersenstraße 32, 64287 Darmstadt (Germany); Brübach, J., E-mail: bruebach@ekt.tu-darmstadt.de [Fachgebiet Reaktive Strömungen und Messtechnik (RSM), Center of Smart Interfaces (CSI), Technische Universität Darmstadt, Petersenstraße 32, 64287 Darmstadt (Germany); Euler, M. [Fachgebiet Reaktive Strömungen und Messtechnik (RSM), Center of Smart Interfaces (CSI), Technische Universität Darmstadt, Petersenstraße 32, 64287 Darmstadt (Germany); Frotscher, M.; Litterscheid, C.; Albert, B. [Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Petersenstraße 18, 64287 Darmstadt (Germany); Dreizler, A. [Fachgebiet Reaktive Strömungen und Messtechnik (RSM), Center of Smart Interfaces (CSI), Technische Universität Darmstadt, Petersenstraße 32, 64287 Darmstadt (Germany)

2013-07-15

With regard to phosphor thermometry, the materials Y{sub 3}Al{sub 5}O{sub 12}:Eu (YAG:Eu) and YAlO{sub 3}:Eu (YAP:Eu) were synthesised and characterised in order to substitute the commonly used thermographic phosphor Y{sub 2}O{sub 3}:Eu, whose temperature sensitive luminescence lifetime exhibits a strong and most often undesirable cross-sensitivity to the oxygen concentration of the surrounding gas phase. The synthesis is outlined in detail and the crystallographic structure was characterised by X-ray diffraction. In a second step, the luminescence properties following pulsed UV laser excitation were determined. In this context, the emission spectra and the temperature lifetime characteristics were monitored. For Y{sub 3}Al{sub 5}O{sub 12}:Eu and YAlO{sub 3}:Eu, temperature sensitive ranges of 1000 K–1470 K and 850 K–1300 K were identified. Contrary to Y{sub 2}O{sub 3}:Eu, both materials do show much lower cross-sensitivities to the oxygen concentration of the surrounding gas phase. - Highlights: ► Y{sub 3}Al{sub 5}O{sub 12}:Eu and YAlO{sub 3}:Eu were synthesised and characterised. ► The synthesis is outlined and the crystallographic structure was characterised. ► Emission spectra and the temperature lifetime characteristics were monitored. ► Compared to Y{sub 2}O{sub 3}:Eu lower sensitivities to the oxyg. conc. of the gas phase emerged.

Reddish-orange, neutral and warm white emissions in Eu3+, Dy3+ and Dy3+/Eu3+ doped CdO-GeO2-TeO2 glasses

Science.gov (United States)

Rodríguez-Carvajal, David A.; Meza-Rocha, A. N.; Caldiño, U.; Lozada-Morales, R.; Álvarez, E.; Zayas, Ma. E.

2016-11-01

Eu3+, Dy3+ and Dy3+/Eu3+ doped CdO-GeO2-TeO2 glasses were prepared using the melt-quenching process and analyzed by X-diffraction, Raman spectroscopy, excitation and emission spectra, and emission decay time profiles. The lack of X ray diffraction peaks revealed that all samples are amorphous. Vibrational modes associated with Tesbnd Osbnd Te and Gesbnd Osbnd Ge related bonds and molecular oxygen were detected by Raman spectroscopy. The luminescence characteristics were studied upon excitations that correspond with the emission of InGaN (370-420 nm) based LEDs. The Eu3+ singly doped glass displayed reddish-orange global emission, with x = 0.601 and y = 0.349 CIE1931 chromaticity coordinates, upon 393 nm excitation. Neutral emission with x = 0.373 and y = 0.412 CIE1931 chromaticity coordinates and correlated color temperature (CCT) of 4400 K, was achieved in the Dy3+ singly doped glass excited at 388 nm. The Dy3+/Eu3+ co-doped glass exhibited warm, neutral and soft warm white emissions with CCT values of 3435, 4153 and 2740 K, under excitations at 382, 388 and 393 nm, respectively, depending mainly on the Dy3+ and Eu3+ relative excitation. The Dy3+ excitation bands observed in the Dy3+/Eu3+ glass by monitoring the 611 nm Eu3+ emission, suggest that Dy3+ → Eu3+ energy transfer takes place, despite the fact that the Dy3+ emission decays in the Dy3+ and Dy3+/Eu3+ doped glass, remain without changes. The shortening of Eu3+ decay in presence of Dy3+ was attributed to an Eu3+ → Dy3+ non-radiative energy transfer process, which according with the Inokuti-Hirayama model might be dominated through an electric quadrupole-quadrupole interaction, with efficiency and probability of 5.5% and 51.6 s-1, respectively.

Synthesis and characterization of polymorphs of photoluminescent Eu(III)-(2,5-furandicarboxylic acid, oxalic acid) MOFs

International Nuclear Information System (INIS)

Shi, Fa-Nian; Ananias, Duarte; Yang, Ting-Hai; Rocha, João

2013-01-01

A novel metal organic framework (MOF) formulated as [Eu(H 2 O) 2 (fdc)(ox) 0.5 ·(H 2 O)] n (1, fdc 2− =2,5-furandicarboxylate, ox 2− =oxalate), was hydrothermally synthesized via in situ ox 2− generation from the partial decomposition of the fdc 2− ligand. This material crystallizes in the monoclinic space group C2/c, unit cell parameters of 1: a=16.7570(10), b=10.5708(7), c=13.5348(14) Å, β=116.917(2)° (Z=8), and exhibits a three-dimensional (3D)-porous framework, with guest water molecules residing in the channel linking all other ligands (H 2 O, ox 2− and fdc 2− ) via hydrogen bonding interactions. Compound 2 is a polymorph of 1 crystallizing in monoclinic P21/c space group. The photoluminescence properties of 1 and 2 were studied at room temperature. The spectra show the typical Eu 3+ red emission and the differences observed reflects the slightly different structures of these polymorphs. - Graphical abstract: Exploring metal organic framework polymorphism in the system Eu(H 2 O) 2 (fdc)(ox) 0.5 ·(H 2 O)] n (fdc 2− =2,5-furandicarboxylate, ox 2− =oxalate) for tuning light emission. Display Omitted - Highlights: • Synthesis of Eu(III)-(2,5-furandicarboxylic acid, oxalic acid) MOF polymorphs. • Detailed single-crystal study of polymorphs including hydrogen-bonding networks. • Photoluminescence spectroscopy show subtle differences light emission properties

A highly triflated rare-earth ion in [Eu(O{sub 3}SCF{sub 3}){sub 8}]{sup 5-}

Energy Technology Data Exchange (ETDEWEB)

Bruns, Joern; Kluener, Thorsten; Kraeuter, Jessica; Wickleder, Mathias S. [Carl von Ossietzky Universitaet Oldenburg, Institut fuer Chemie (Germany); Krueger, Sascha; Adlung, Matthias; Wickleder, Claudia [Universitaet Siegen, Institut fuer Anorganische Chemie (Germany); Niehaus, Oliver; Poettgen, Rainer [Westfaelische Wilhelms Universitaet Muenster, Institut fuer Anorganische und Analytische Chemie (Germany)

2015-08-24

The reaction of Eu{sub 2}O{sub 3} with fuming nitric acid, trifluormethanesulfonic acid, and its anhydride in torch-sealed glass ampoules at 120 C gave the europium compound (NO){sub 5}[Eu(O{sub 3}SCF{sub 3}){sub 8}] (orthorhombic, Fddd, Z=16, a=1932.69(4), b=2878.44(7), c=2955.12(7) pm, V=16439.7(7) Aa{sup 3}). The compound exhibits the [Eu(O{sub 3}SCF{sub 3}){sub 8}]{sup 5-} anion showing for the first time a lanthanide ion that is exclusively coordinated by eight triflate anions. The anion has been further investigated by DFT calculations, which also allowed clear assignment of the vibrational spectra. Moreover, magnetochemical and luminescence measurements gave additional insight into the properties of this complex. The luminescence spectra revealed that the Eu{sup 3+} ions are in a pseudo D{sub 4d} symmetric environment. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

5,5-Dimethyl-2-methylseleno-1,3,2-dioxaphosphorinan-2-one

Directory of Open Access Journals (Sweden)

Grzegorz Cholewinski

2010-04-01

Full Text Available The title compound, C6H13O3PSe, was obtained in the reaction of 5,5-dimethyl-2-oxo-2-seleno-1,3,2-dioxaphosphorinane potassium salt with methyl iodide. The selenomethyl group is in the axial position in relation to the six-membered dioxaphosphorinane ring.

In vivo immunotoxicity of SiO2@(Y0.5Gd0.45Eu0.05)2O3 as dual-modality nanoprobes.

Science.gov (United States)

Tian, Xiumei; Li, Ermao; Yang, Fanwen; Peng, Ye; Zhu, Jixiang; He, Fupo; Chen, Xiaoming

2014-08-07

We have successfully synthesized SiO2@(Y0.5Gd0.45Eu0.05)2O3 nanocomposites as a potential dual-modality nanoprobe for molecular imaging in vitro. However, their immunotoxicity assessment in vivo remains unknown. In this article, the in vitro biocompatibility of our dual-modality nanoprobes was assayed in terms of cell viability and apoptosis. In vivo immunotoxicity was investigated by monitoring the generation of reactive oxygen species (ROS), cluster of differentiation (CD) markers and cytokines in Balb/c mice. The data show that the in vitro biocompatibility was satisfactory. In addition, the immunotoxicity data revealed there are no significant changes in the expression levels of CD11b and CD71 between the nanoprobe group and the Gd in a diethylenetriaminepentaacetic acid (DTPA) chelator (Gd-DTPA) group 24 h after injection in Balb/c mice (p>0.05). Importantly, there are significant differences in the expression levels of CD206 and CD25 as well as the secretion of IL-4 and the generation of ROS 24 h after injection (pimmunotoxicity of these rare earth-based biomaterials at the molecular level before molecular imaging in vivo.

CORRIGENDUM First principles study of crystalline and amorphous Ge2Sb2Te5 and the effects of stoichiometric defects First principles study of crystalline and amorphous Ge2Sb2Te5 and the effects of stoichiometric defects

Science.gov (United States)

Caravati, S.; Bernasconi, M.; Kühne, T. D.; Krack, M.; Parrinello, M.

2010-10-01

The distributions of coordination numbers reported in the insets of figure 7 actually refer to a bonding cutoff of 3.2 Å for all pairs of atoms. The distributions of coordination numbers referred to in the paper with bonding cutoff equal to 3.2 Å for all pairs but Sb-Te for which the bonding cutoff was set to the outer edge of the pair correlation function of c-GST (3.4 Å at 300 K) are given below for the three compounds. figure 1 Figure 7. Distribution of coordination numbers of different species obtained by integration of the partial pair correlation functions for (from left to right) Ge2Sb2Te5, Ge2Sb1.8Te5 and Ge2.2Sb2Te5.

Magnetic structure of the YbMn2SbBi compound

International Nuclear Information System (INIS)

Morozkin, A.V.; Manfrinetti, P.

2011-01-01

Graphical abstract: Display Omitted Research highlights: → A neutron diffraction investigation in zero applied field of La 2 O 2 S-type YbMn 2 SbBi shows antiferromagnetic ordering below 138(3) K and ferrimagnetic ordering below 112(3) K. → Between 138 and 112 K, the magnetic structure of YbMn 2 SbBi consists of antiferromagnetically coupled ab-plane magnetic moments of the manganese atoms (D 1d magnetic point group). → Below 112(3) K, the magnetic structure of YbMn 2 SbBi becames the sum antiferromagnetic component with D 1d magnetic point group and ferromagnetic one with C 2 magnetic point group. → The magnitude of Yb and Mn magnetic moments in YbMn 2 SbBi at 2 K (M Yb = 3.6(2) μ B , M Mn = 3.5(2) μ B ) correspond to the trivalent state of the Yb ions and tetravalent state of the Mn ions. - Abstract: A neutron diffraction investigation has been carried out on the trigonal La 2 O 2 S-type (hP5, space group P3-bar ml, No. 164; also CaAl 2 Si 2 -type) YbMn 2 SbBi intermetallic compound. The YbMn 2 SbBi presents antiferromagnetic ordering below 138(3) K and ferrimagnetic ordering below 112(3) K. Between 138 and 112 K, the magnetic structure of YbMn 2 SbBi consists of antiferromagnetically coupled ab-plane magnetic moments of the manganese atoms (D 1d magnetic point group). Below 112(3) K, the ferromagnetic components of Yb and Mn begin to develop, and the magnetic structure of YbMn 2 SbBi becames the sum antiferromagnetic component with D 1d magnetic point group and ferromagnetic one with C 2 magnetic point group. The magnitude of Yb and Mn magnetic moments in YbMn 2 SbBi at 2 K (M Yb = 3.6(2) μ B , M Mn = 3.5(2) μ B ) correspond to the trivalent state of the Yb ions and tetravalent state of the Mn ions.

Synthesis, crystal structure, and magnetic properties of quaternary iron selenides: Ba{sub 2}FePnSe{sub 5} (Pn=Sb, Bi)

Energy Technology Data Exchange (ETDEWEB)

Wang, Jian; Greenfield, Joshua T.; Kovnir, Kirill

2016-10-15

Two new barium iron pnictide–selenides, Ba{sub 2}FeSbSe{sub 5} and Ba{sub 2}FeBiSe{sub 5}, were synthesized by a high-temperature solid-state route and their crystal structures were determined using single crystal X-ray diffraction. Both compounds are isomorphic to the high pressure phase Ba{sub 3}FeS{sub 5} and crystallize in the orthorhombic space group Pnma (No. 62) with cell parameters of a=12.603(2)/12.619(2) Å, b=9.106(1)/9.183(1) Å, c=9.145(1)/9.123(1) Å and Z=4 for Ba{sub 2}FeSbSe{sub 5} and Ba{sub 2}FeBiSe{sub 5}, respectively. According to differential scanning calorimetry, Ba{sub 2}FePnSe{sub 5} compounds exhibit high thermal stability and melt congruently at 1055(5) K (Pn=Sb) and 1105(5) K (Pn=Bi). Magnetic characterizations reveal strong antiferromagnetic nearest-neighbor interactions in both compounds resulting in an antiferromagnetic ordering at 58(1) K for Ba{sub 2}FeSbSe{sub 5} and 79(2) K for Ba{sub 2}FeBiSe{sub 5}. The magnetic interactions between Fe{sup 3+} centers, which are at least 6 Å apart from each other, are mediated by superexchange interactions. - Graphical abstract: In Ba{sub 2}FeSbSe{sub 5} and Ba{sub 2}FeBiSe{sub 5} the magnetic interactions between Fe{sup 3+} centers, which are at least 6 Å apart from each other, are mediated by superexchange interactions. - Highlights: • New compounds Ba{sub 2}FeSbSe{sub 5} and Ba{sub 2}FeBiSe{sub 5} have been synthesized. • The crystal structure was determined by single crystal X-ray diffraction. • Both compounds melt congruently at temperatures above 1000 K. • Ba{sub 2}FeSbSe{sub 5} and Ba{sub 2}FeBiSe{sub 5} exhibit AFM ordering at 58 K (Sb) and 70 K (Bi). • Magnetic exchange between Fe{sup 3+} is mediated by either Se–Sb(Bi)–Se or Se–Ba–Se bridges.

Raman spectra of the system TeCl4-SbCl5

International Nuclear Information System (INIS)

Brockner, W.; Demiray, A.F.

1980-01-01

Raman spectra of the solid and molten TeCl 4 . SbCl 5 addition compound and of some TeCl 4 -SbCl 5 mixtures have been recorded. Two modifications of the crystalline TeCl 4 -SbCl 5 compound have been found. The structure of the melt can be described by the equilibrium TeCl 3 + + SbCl 6 - reversible TeCl 4 + SbCl 5 lying on the left side. Mixtures with other stoichiometry contain the 1:1 adduct only and excess TeCl 4 or SbCl 5 , respectively. Such melts are built up by the ionic species TeCl 3 + and SbCl 6 - also and TeCl 4 or SbCl 5 according to stoichiometry. (author)

Electronic structure and transport properties of Ba2Cd2Pn3 (Pn = As and Sb): An efficient materials for energy conversion

International Nuclear Information System (INIS)

Reshak, A.H.

2016-01-01

The full potential method within the recently modified Becke-Johnson potential explore that the Ba 2 Cd 2 Pn 3 (Pn = As and Sb) compounds are narrow band gap semiconductors of about 0.49 and 0.32 eV, which confute the finding of the previous TB-LMTO-ASA calculation that Ba 2 Cd 2 Sb 3 is a poor metal. It has been found that there are subtle difference in band desperations of the two compounds, resulting in significant influence on the electronic and transport properties, taking into account the size and the electro-negativity differences between As and Sb atoms. Calculation show that there exists a strong hybridization between the orbitals which may lead to form covalent bonding which is more favorable for the transport of the carriers than ionic one. The electronic structure, the anisotropy and the inter-atomic interactions are further analyzed by calculating the valence electronic charge density distribution in two crystallographic planes. The semi-classical Boltzmann theory as incorporated in BoltzTraP code was used to calculate the transport properties of Ba 2 Cd 2 As 3 and Ba 2 Cd 2 Sb 3 at different temperatures and chemical potentials to ascertain the influence of temperatures and substituting As by Sb on the transport properties. The carries mobility decreases with increasing the temperature also with increasing the carriers concentration. We have observed that substituting As by Sb lead to increase the carries mobility of Ba 2 Cd 2 Sb 3 along the whole temperature interval and the carries concentration range. It has been found that Ba 2 Cd 2 As 3 exhibit higher carriers concentration, electronic electrical conductivity and Seebeck coefficient than that of Ba 2 Cd 2 Sb 3 along the investigated temperature range. The highest value of Seebeck coefficient occurs at 300 K, which show good agreement with the experimental data. The power factor increases linearly with increasing the temperature and Ba 2 Cd 2 As 3 exhibit a bit higher power factor than that of Ba

Hydrothermal synthesis, characterization, and luminescence of Ca_2B_2O_5:RE (RE = Eu"3"+, Tb"3"+, Dy"3"+) nanofibers

International Nuclear Information System (INIS)

Yang, Li; Wan, Yingpeng; Li, Yuze; Pu, Yinfu; Huang, Yanlin; Chen, Cuili; Seo, Hyo Jin

2016-01-01

Ca_2B_2O_5:RE (RE = Eu"3"+, Tb"3"+, Dy"3"+) nanofibers were synthesized by the hydrothermal reaction method. The structural refinement was conducted on the base of the X-ray powder diffraction (XRD) measurements. The surface properties of the Ca_2B_2O_5:RE (RE = Eu"3"+, Tb"3"+, Dy"3"+) nanofibers were investigated by the measurements such as the scanning electron microscope (SEM), transmission electron microscope (TEM), and the energy dispersive spectrum (EDS). The nanofiber has a diameter of about 100 nm and a length of several micrometers. The luminescence properties such as photoluminescence excitation (PLE) and emission spectra (PL), decay lifetime, color coordinates, and the absolute internal quantum efficiency (QE) were reported. Ca_2B_2O_5:Eu"3"+ nanofibers show the red luminescence with CIE coordinates of (x = 0.41, y = 0.51) and the luminescence lifetime of 0.63 ms. The luminescence of Ca_2B_2O_5:Tb"3"+ nanofibers is green color (x = 0.29, y = 0.53) with the lifetime of 2.13 ms. However, Dy"3"+-doped Ca_2B_2O_5 nanofibers present a single-phase white-color phosphor with the fluorescence decay of 3.05 ms. Upon near-UV excitation, the absolute quantum efficiency is measured to be 65, 35, and 37 % for Eu"3"+-, Tb"3"+-, Dy"3"+-doped Ca_2B_2O_5 nanofibers, respectively. It is suggested that Ca_2B_2O_5:RE (RE = Eu"3"+, Tb"3"+, Dy"3"+) nanofibers could be an efficient phosphor for lighting and display.

Investigation of the transport properties and compositions of the Ca{sub 2}RE{sub 7}Pn{sub 5}O{sub 5} series (RE=Pr, Sm, Gd, Dy; Pn=Sb, Bi)

Energy Technology Data Exchange (ETDEWEB)

Forbes, Scott [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1 (Canada); Yuan, Fang [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1 (Canada); Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Kosuda, Kosuke; Kolodiazhnyi, Taras [Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Mozharivskyj, Yurij, E-mail: mozhar@mcmaster.ca [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1 (Canada)

2016-10-15

The Ca{sub 2}RE{sub 7}Pn{sub 5}O{sub 5} phases (RE=Pr, Sm, Gd, Dy; Pn=Sb, Bi) were successfully prepared from high temperature reactions at 1225–1300 °C. These phases maintain the same structure types as the parent RE{sub 9}Pn{sub 5}O{sub 5} phases, except for a Ca/RE mixing. The study and preparation of these phases was motivated by the desire to shift the metallic type properties of the parent RE{sub 9}Pn{sub 5}O{sub 5} phases to a level more suitable for thermoelectric applications. Electrical resistivity measurements performed on pure, bulk samples indicated all phases to be narrow band gap semiconductors or semimetals, supporting the charge balanced electron count of the Ca{sub 2}RE{sub 7}Pn{sub 5}O{sub 5} composition. Unfortunately, all samples are too electrically resistive for any potential usage as thermoelectrics. Electronic band structure calculations performed on idealized RE{sub 9}Pn{sub 5}O{sub 5} structures revealed the presence of a pseudogap at the Fermi level, which is consistent with the observed electrical resistivity and Seebeck coefficient behavior. - Graphical abstract: Ca substitution in RE{sub 9}Pn{sub 5}O{sub 5} leads to charge-balanced Ca{sub 2}RE{sub 7}Pn{sub 5}O{sub 5} phases with semiconducting or semimetallic properties. - Highlights: • The RE{sub 9}Pn{sub 5}O{sub 5} structure may be stabilized with calcium substitution in the form of Ca{sub 2}RE{sub 7}Pn{sub 5}O{sub 5}. • The Ca{sub 2}RE{sub 7}Pn{sub 5}O{sub 5} phases maintain the parent P 4/n structure, albeit with Ca/RE mixing. • The Ca{sub 2}RE{sub 7}Sb{sub 5}O{sub 5} phases behave as semiconductors while Ca{sub 2}RE{sub 7}Bi{sub 5}O{sub 5} are semimetals with electron-electron correlations. • Electronic structure calculations yield a semimetal-like density of states for both Ca{sub 2}RE{sub 7}Sb{sub 5}O{sub 5} and Ca{sub 2}RE{sub 7}Bi{sub 5}O{sub 5}.

Performance PtSnRh electrocatalysts supported on carbon-Sb2O5.SbO2 for the electro-oxidation of ethanol, prepared by an alcohol-reduction process

International Nuclear Information System (INIS)

Castro, Jose Carlos

2013-01-01

PtSnRh electrocatalysts supported on carbon-Sb 2 O 5 .SnO 2 , with metal loading of 20 wt%, were prepared by an alcohol-reduction process, using H 2 PtCl 6 .6H 2 O (Aldrich), RhCl 3 .xH 2 O (Aldrich) and SnCl 2 .2H 2 O (Aldrich), as source of metals; Sb 2 O 5 .SnO 2 (ATO) and carbon Vulcan XC72, as support; and ethylene glycol as reducing agent. The electrocatalysts obtained were characterized physically by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The diffractograms showed which PtSnRh/C-ATO electrocatalysts had FCC structure of Pt and Pt alloys, besides several peaks associated with SnO 2 and ATO. The average sizes of crystallites were between 2 and 4 nm. TEM micrographs showed a good distribution of the nanoparticles on the support. The average sizes of particles were between 2 and 3 nm, with good agreement for the average size of the crystallites. The performances of the electrocatalysts were analyzed by electrochemical techniques and in real conditions of operation using single direct ethanol fuel cell. In the chronoamperometry at 50 deg C, the electrocatalysts with carbon (85 wt%) and ATO (15 wt%) support, showed the best activity, and the atomic proportions which achieved the best results were PtSnRh(70:25:05) e (90:05:05). PtSnRh(70:25:05)/85C+15ATO electrocatalysts showed the best performance in a direct ethanol fuel cell. (author)

The feasibility of boron containing phosphors in thermal neutron image plates, in particular the systems M sub 2 B sub 5 O sub 9 X : Eu sup 2 sup + (M=Ca, Sr, Ba; X=Cl, Br) Part II: experimental results

CERN Document Server

Knitel, M J; Dorenbos, P; Eijk, C W E; Berezovskaya, I V; Dotsenko, V

2000-01-01

The storage phosphor properties of the compounds M sub 2 B sub 5 O sub 9 X : Eu sup 2 sup + (M=Ca, Sr, Ba; X=Cl, Br) have been studied. The best compounds, Sr sub 2 B sub 5 O sub 9 Br : Eu sup 2 sup + and Ca sub 2 B sub 5 O sub 9 Br : Eu sup 2 sup + , show a photostimulated luminescence yield of, respectively, 21 and 14 photons per incident thermal neutron. They contain natural boron. With these yields, image plates with detective quantum efficiency values of more than 40% are envisaged when using enriched sup 1 sup 0 B, but the stimulation energy at 633 nm is too high.

Triphenylbis(2,4,5-trifluoro-3-methoxybenzoatoantimony(V

Directory of Open Access Journals (Sweden)

Daqi Wang

2008-10-01

Full Text Available In the title compound, [Sb(C6H53(C8H4F3O32], the Sb atom lies on an inversion centre and exhibits a trigonal bipyramidal geometry with the axial positions occupied by the O atoms of two carboxylate groups and the equatorial positions occupied by C atoms of the phenyl groups. Intramolecular C—H...O hydrogen bonds stabilize the molecular conformation. In the crystal structure, molecules are connected by intermolecular C—H...O hydrogen-bonding interactions, forming a layer structure parallel to (overline{2}01.

The performance of Pt nanoparticles supported on Sb{sub 2}O{sub 5}.SnO{sub 2}, on carbon and on physical mixtures of Sb{sub 2}O{sub 5}.SnO{sub 2} and carbon for ethanol electro-oxidation

Energy Technology Data Exchange (ETDEWEB)

Oliveira Neto, A.; Brandalise, M.; Dias, R.R.; Ayoub, J.M.S.; Silva, A.C.; Penteado, J.C.; Linardi, M.; Spinace, E.V. [Instituto de Pesquisas Energeticas e Nucleares, IPEN - CNEN/SP, Av. Prof. Lineu Prestes, 2242 - Cidade Universitaria - CEP 05508-900 Sao Paulo, SP (Brazil)

2010-09-15

Pt nanoparticles were supported on Sb{sub 2}O{sub 5}.SnO{sub 2} (ATO), on carbon and on physical mixtures of ATO and carbon by an alcohol-reduction process using ethylene glycol as reducing agent. The obtained materials were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Their performance for ethanol oxidation was investigated at room temperature by chronoamperometry and in a direct ethanol fuel cell (DEFC) at 100 C. Pt nanoparticles supported on a physical mixture of ATO and carbon showed a significant increase of performance for ethanol oxidation compared to Pt nanoparticles supported on ATO or on carbon. (author)

Role of the dimensionality of the [GaX]2 network in the Zintl phases EuGa2X2

KAUST Repository

Singh, Nirpendra

2012-11-28

The structural, electronic, magnetic, optical, and thermoelectric properties of EuGa2X2 (X = P, As, and Sb) are investigated using first principles calculations (taking into account the onsite Coulomb interaction) and the semi-classical Boltzmanntheory. The divalent nature of Eu fulfils the Zintl principle as is confirmed by the calculated total magnetic moments of ∼7 μB. A metallic behavior is obtained for all compounds. The optical spectra originate mainly from the transitions between occupied Eu 4f states and unoccupied Eu 5d states. It is demonstrated that the two-dimensional [Ga(P/As)]2 network in EuGa2P2 and EuGa2As2 is favorable for thermoelectric applications as compared to the three-dimensional [GaSb]2 network in EuGa2Sb2.

Poly[(μ3-benzene-1,3,5-tricarboxylato-κ3O1:O3:O5(μ2-2-methylimidazolato-κ2N:N′tris(2-methylimidazole-κNdizinc(II

Directory of Open Access Journals (Sweden)

Palanikumar Maniam

2011-06-01

Full Text Available Hydrothermal reaction involving zinc nitrate hexahydrate, trisodium benzene-1,3,5-tricarboxylate (Na3BTC and 2-methylimidazole (2-MeImH yielded the title compound, [Zn2(C9H3O6(C4H5N2(C4H6N23]. In this mixed-ligand metal-organic compound, Zn2+ ions are coordinated by N atoms from 2-MeImH molecules and (2-MeIm− ions, as well as by O atoms from (BTC3− ions. This results in two different distorted tetrahedra, viz. ZnN3O and ZnN2O2. These tetrahedra are interconnected via (BTC3− ions and N:N′-bridging (2-MeIm− ions, thus forming a layered structure in the bc plane. Hydrogen bonds between the O atoms of carboxylate ions and NH groups of 2-MeImH ligands link the layers into a three-dimensional structure.

Phase change behaviors of Zn-doped Ge2Sb2Te5 films

International Nuclear Information System (INIS)

Wang Guoxiang; Nie Qiuhua; Shen Xiang; Fu Jing; Xu Tiefeng; Dai Shixun; Wang, R. P.; Wu Liangcai

2012-01-01

Zn-doped Ge 2 Sb 2 Te 5 phase-change materials have been investigated for phase change memory applications. Zn 15.16 (Ge 2 Sb 2 Te 5 ) 84.84 phase change film exhibits a higher crystallization temperature (∼258 °C), wider band gap (∼0.78 eV), better data retention of 10 years at 167.5 °C, higher crystalline resistance, and faster crystallization speed compared with the conventional Ge 2 Sb 2 Te 5 . The proper Zn atom added into Ge 2 Sb 2 Te 5 serves as a center for suppression of the face-centered-cubic (fcc) phase to hexagonal close-packed (hcp) phase transition, and fcc phase has high thermal stability partially due to the bond recombination among Zn, Sb, and Te atoms.

Thermal expansion studies on europium titanate (Eu2TiO5)

International Nuclear Information System (INIS)

Panneerselvam, G.; Subramanian, G.G.S.; Antony, M.P.

2008-01-01

The lattice thermal expansion characteristics of europium titanate (Eu 2 TiO 5 ) have been studied by measuring the lattice parameter by high temperature X-ray diffraction technique (HT-XRD) in the temperature range 298-1573K. Percentage linear thermal expansion and mean linear thermal expansion coefficients were computed from the lattice parameter data. The percentage linear thermal expansion in the temperature range 298-1573 K along a, b and c axes are 1.05, 1.15 and 0.95 respectively. (author)

1-Methoxy-3-o-tolylbicyclo[2.2.2]oct-5-ene-2,2-dicarbonitrile

Directory of Open Access Journals (Sweden)

Orhan Büyükgüngör

2009-09-01

Full Text Available In the title compound, C18H18N2O, the cyclohexene and cyclohexane rings of the bicyclo[2.2.2]oct-5-ene unit adopt distorted boat conformations. In the crystal, molecules exist as C—H...N hydrogen-bonded centrosymmetric R22(14 dimers, which are further linked by C—H...π interactions.

Solid-state synthesis, structure and properties of a novel open-framework cadmium selenite bromide: [Cd10(SeO3)8Br4]·HBr·H2O

International Nuclear Information System (INIS)

Chen, Wen-Tong; Wang, Ming-Sheng; Wang, Guan-E; Chen, Hui-Fen; Guo, Guo-Cong

2013-01-01

A novel open-framework cadmium selenite bromide, [Cd 10 (SeO 3 ) 8 Br 4 ]·HBr·H 2 O (1), has been obtained by a solid-state reaction at 450 °C, and the structure has been determined by single-crystal X-ray diffraction analysis. Compound 1 crystallizes in Pbcm of the orthorhombic system: a=10.882(3), b=16.275(5), c=18.728(6) Å, V=3317(2) Å 3 , R1/wR2=0.0411/0.0659. Compound 1 is characteristic of a novel 3-D open-framework structure, composing ∞ 2 [CdSeO 3 ] layers and the pillars of edge-shared CdO 3 Br 2 square pyramids. The lattice water molecules and the HBr molecules locate in the voids of the framework. Optical absorption spectrum of 1 reveals the presence of an optical gap of 1.65 eV. Solid-state photoluminescent study indicates that compound 1 exhibits strong violet emission. TG–DSC measurement shows that compound 1 is thermally stable up to 200 °C. - Graphical abstract: A metal selenite halide has been synthesized and features a 3-D open-framework structure, composing edge-shared CdO 8 decahedra and pillars of edge-sharing pentahedra. UV–vis, TG–DSC and luminescent measurements are also reported. Highlights: • This paper reports a novel cadmium selenite bromide obtained by an intermediate-temperature solid-state reaction. • The title compound is characteristic of a novel 3-D open-framework structure, composing ∞ 2 [CdSeO 3 ] layers and the pillars of edge-shared CdO 3 Br 2 square pyramids. • The title compound is thermally stable up to 200 °C. • The title compound has an optical gap of 1.65 eV and exhibits strong violet emission

Synthesis and characterization of polymorphs of photoluminescent Eu(III)-(2,5-furandicarboxylic acid, oxalic acid) MOFs

Science.gov (United States)

Shi, Fa-Nian; Ananias, Duarte; Yang, Ting-Hai; Rocha, João

2013-08-01

A novel metal organic framework (MOF) formulated as [Eu(H2O)2(fdc)(ox)0.5·(H2O)]n (1, fdc2-=2,5-furandicarboxylate, ox2-=oxalate), was hydrothermally synthesized via in situ ox2- generation from the partial decomposition of the fdc2- ligand. This material crystallizes in the monoclinic space group C2/c, unit cell parameters of 1: a=16.7570(10), b=10.5708(7), c=13.5348(14) Å, β=116.917(2)° (Z=8), and exhibits a three-dimensional (3D)-porous framework, with guest water molecules residing in the channel linking all other ligands (H2O, ox2-and fdc2-) via hydrogen bonding interactions. Compound 2 is a polymorph of 1 crystallizing in monoclinic P21/c space group. The photoluminescence properties of 1 and 2 were studied at room temperature. The spectra show the typical Eu3+ red emission and the differences observed reflects the slightly different structures of these polymorphs.

New antiferromagnetic semiconductor CuCr1.5Sb0.5S4

International Nuclear Information System (INIS)

Kesler, Ya.A.; Koroleva, L.I.; Mikheev, M.G.; Odintsov, A.G.; Filimonov, D.S.

1993-01-01

New halcogenide compound with spinel-antiferromagnetic semiconductor CuCr 1.5 Sb 0.5 S 4 are obtained and studied for the first time. Magnetic properties of this compound, namely, magnetization linear dependence, maximum on PHI(T) curve in the low-temperature area and realization of the Curie-Weis law for paramagnetic susceptibility with negative paramagnetic temperature testiby to the fact that this compound is antiferromagnetic

The spectral characteristics of Gd sub 2 SiO sub 5 :Eu sup 3 sup + in VUV-UV range

CERN Document Server

Chen Yong; Wei Ya Guang; Tao Ye

2002-01-01

Synchrotron radiation source was used to investigated the spectral characteristics of Gd sub 2 SiO sub 5 :Eu sup 3 sup + in VUV-UV range. The various energy transfers at room temperature and 10 K, including from host or Gd sup 3 sup + ions to Eu sup 3 sup + ions and transfer between Eu sup 3 sup + ions at two different lattice sites, were discussed. In addition the emission spectra under 186 nm and 276 nm excitation were compared from the view of quantum cutting. The results indicate that Gd sub 2 SiO sub 5 :Eu sup 3 sup + is a kind of material with potential high efficiency quantum cutting

Novel bluish white-emitting CdBaP{sub 2}O{sub 7}:Eu{sup 2+} phosphor for near-UV white-emitting diodes

Energy Technology Data Exchange (ETDEWEB)

Derbel, Mouna [Laboratory of Industrial Chemistry, National School of Engineers of Sfax, University of Sfax, BPW 3038 Sfax (Tunisia); Mbarek, Aïcha, E-mail: mbarekaicha@yahoo.fr [Laboratory of Industrial Chemistry, National School of Engineers of Sfax, University of Sfax, BPW 3038 Sfax (Tunisia); Chadeyron, Geneviève [Clermont Université, ENSCCF, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand (France); Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand (France); Fourati, Mohieddine [Laboratory of Industrial Chemistry, National School of Engineers of Sfax, University of Sfax, BPW 3038 Sfax (Tunisia); Zambon, Daniel [Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand (France); Mahiou, Rachid [Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR 6296, ICCF, BP 80026, F-63171 Aubiere (France)

2016-08-15

A new bluish white-emitting phosphor based on a phosphate host matrix, CdBaP{sub 2}O{sub 7}:Eu{sup 2+}, was prepared by a conventional solid-state reaction method. The photoluminescence properties were investigated in both ultraviolet (UV) and vacuum ultraviolet (VUV) regions. The band-gaps of Eu-doped CdBaP{sub 2}O{sub 7} powders can be tuned in the ranges of 2.26–2 eV. The Eu{sup 2+}-doped CdBaP{sub 2}O{sub 7} phosphor was efficiently excited at wavelengths of 250–400 nm, which is suitable for the blue emission band for near-UV light-emitting-diode (LED) chips (360–400 nm) and red emission peaks up to 700 nm. CdBaP{sub 2}O{sub 7}:Eu{sup 2+} displays two different luminescence centers, which were suggested to Ba{sup 2+} and Cd{sup 2+} sites in the host. The dependence of luminescence intensity on temperatures was measured. The chromaticity coordinates and activation energy for thermal quenching were reported. The phosphor shows a good thermal stability on temperature quenching.

Poly[[diaquabis(2,2′-bipyridine-κ2N,N′(μ3-5-hydroxyisophthalato-κ5O1,O1′:O3,O3′:O3′(μ3-5-hydroxyisophthalato-κ4O1,O1′:O3:O3′(μ2-5-hydroxyisophthalato-κ3O1,O1′:O3didysprosium(III] dihydrate

Directory of Open Access Journals (Sweden)

Yan-Lin Zhang

2011-10-01

Full Text Available The polymeric title compound, {[Dy2(C8H4O53(C10H8N22(H2O2]·2H2O}n, contains two independent DyIII ions, both of which are nine-coordinated in a distorted tricapped trigonal–prismatic geometry. One DyIII ion is coordinated by five 5-hydroxyisophthalate (hip ligands and one 2,2′-bipyridine (bpy ligand and the other by three hip ligands, one bpy ligand and two water molecules. The DyIII ions are bridged by the carboxylate groups of the hip ligands, forming a three-dimensional framework. O—H...O hydrogen bonds are present in the crystal structure.

Satellite line mapping in Eu3+–Ce3+ and Pr3+–Ce3+ codoped Y2SiO5

International Nuclear Information System (INIS)

Serrano, D.; Karlsson, J.; Zheng, L.; Dong, Y.; Ferrier, A.; Goldner, P.; Walther, A.; Rippe, L.; Kröll, S.

2016-01-01

In this work we perform a high-resolution spectroscopic investigation of Eu 3+ –Ce 3+ and Pr 3+ –Ce 3+ codoped Y 2 SiO 5 crystals. Satellite line spectra were recorded at low temperatures around the Eu 3+ : 7 F 0 → 5 D 0 and the Pr 3+ : 3 H 4 → 1 D 2 transitions. It is observed that the incorporation of Ce 3+ as a codopant notably changes the Eu 3+ and Pr 3+ satellite line patterns. Satellite lines measured in singly doped Eu 3+ :Y 2 SiO 5 were found at the same spectral positions in Eu 3+ –Ce 3+ codoped crystals. These coincident lines were concluded to be due to pairs of Eu 3+ ions. Extra satellite lines appeared in the codoped crystals, which were assigned to Ce 3+ related structures such as Ce 3+ –Eu 3+ pairs. The analysis of the Pr 3+ satellite line spectra presents further challenges. Satellite lines associated to Pr 3+ pairs show weaker intensity, presumably due to the efficient quenching of the Pr 3+1 D 2 emission through cross-relaxation paths ( 1 D 2 → 1 G 4 ; 3 H 4 → 3 F 4 ). The investigation of the Eu 3+ and Pr 3+ satellite line patterns in Y 2 SiO 5 is particularly interesting for their exploitation in rare-earth based quantum computation schemes. - Highlights: • We recorded Eu and Pr satellite lines in Y 2 SiO 5 with and without Ce as a codopant. • The presence of Ce leads to the appearance of extra satellite lines in the spectra. • The satellite lines are associated to minor crystal sites such as ion pairs. • Less than 100 ion pairs were detected per satellite line. • The exploitation of the satellite line structure is proposed for quantum computing.

Photoelectrochemical response and corrosion behavior of CdS/TiO2 nanocomposite films in an aerated 0.5 M NaCl solution

Science.gov (United States)

Boonserm, Aleena; Kruehong, Chaiyaput; Seithtanabutara, Varinrumpai; Artnaseaw, Apichart; Kwakhong, Panomkorn

2017-10-01

This research aimed to investigate the photoelectrochemical response and corrosion behavior of CdS/TiO2 nanocomposite films using electrochemical measurements in an aerated 0.5 M NaCl solution under white light illumination. The CdS/TiO2 nanocomposite films were prepared by chemical bath deposition technique in a solution of cadmium and sulfide ions. The high resolution images of CdS/TiO2 nanocomposite films were provided by field emission scanning electron microscope. Theirs chemical identification and quantitative compositional information, crystallinity and actual chemical compounds formed were determined by energy dispersive spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy, respectively. The results indicated that the photoelectrochemical activity of the films depended strongly on CdS content. From the preparation of CdS/TiO2 nanocomposite films by 5, 10 and 15 dipping cycles in the chemical solutions, the best photoelectrochemical response was revealed by the 10 dipping cycles-prepared film. Galvanic couple testing demonstrated that the photoelectrochemical response of the film decreased continuously compared to that of anodized nanoporous TiO2 substrate which described by photocorrosion of CdS nanoparticles. In addition, chloride-ion attack also induced pitting corrosion leading to fluctuation and deterioration of photoelectrochemical response. CdO2 and Cd(OH)2 depositions were found as the main photocorrosion products on collapsed nanostructured-surface. The relevance between photoelectrochemical response and corrosion behavior of CdS/TiO2 nanocomposite film was discussed in detail.

Crossrelaxations and non-radiative energy transfer from ({sup 4}G{sub 5/2}) Sm{sup 3+} → ({sup 5}D{sub 0}) Eu{sup 3+}: B{sub 2}O{sub 3}–ZnO glasses

Energy Technology Data Exchange (ETDEWEB)

Naresh, V., E-mail: varna.naresh@gmail.com; Rudramadevi, B.H.; Buddhudu, S., E-mail: profsb_svuniv@hotmail.com

2015-05-25

Graphical abstract: The energy transfer process occurring from Sm{sup 3+} to Eu{sup 3+} in B{sub 2}O{sub 3}–ZnO (BZn) glasses is analyzed. Based on the Foster–Dexter theory, the possibility of energy transfer between Sm{sup 3+} and Eu{sup 3+} has been demonstrated from the spectral overlap of Eu{sup 3+} absorption and Sm{sup 3+} emission, photoluminescence spectra, energy level diagram and lifetime measurements. The energy transfer mechanism in (Sm{sup 3+} + Eu{sup 3+}) co-doped glass is governed by dipole–dipole interaction. - Highlights: • Spectroscopic properties of individually doped Sm{sup 3+}, Eu{sup 3+} & co-doped (Sm{sup 3+} + Eu{sup 3+}) in BZn glasses were studied separately. • The effect of Eu{sup 3+} concentration on luminescence properties is explained from cross-relaxations. • Energy transfer from Sm{sup 3+} ({sup 4}G{sub 5/2}) to Eu{sup 3+} ({sup 5}D{sub 0}) has been explained from Foster–Dexter theory. • Dipole–dipole mechanism governs the energy transfer from Sm{sup 3+} to Eu{sup 3+}. - Abstract: The present paper reports on the results concerning to photoluminescence features of Eu{sup 3+}, Sm{sup 3+} ions and energy transfer process occurring from Sm{sup 3+} to Eu{sup 3+} doped in 45 B{sub 2}O{sub 3}–55 ZnO (BZn) glasses prepared by melt quenching technique. Luminescence quenching as a function of Eu{sup 3+} concentration in BZn glasses has been discussed. Among the studied concentrations, 0.5 mol% of Eu{sup 3+} is optimized because it has exhibited red emission transition {sup 5}D{sub 0} → {sup 7}F{sub 2}. With regard to Sm{sup 3+} glasses, orange emission at 602 nm ({sup 4}G{sub 5/2} → {sup 6}H{sub 7/2}) has been noticed on exciting with λ{sub exci} = 403 nm. Based on the Foster–Dexter theory, the possibility of energy transfer between Sm{sup 3+} and Eu{sup 3+} has been explained from the spectral overlap of Eu{sup 3+} absorption and Sm{sup 3+} emission. The optimized concentration 0.5 mol% of Eu{sup 3+} is co

Lattice mismatch and energy transfer of Eu- and Dy-codoped MO–Al2O3–SrO (M=Mg, Ca, Ba) ternary compounds affecting luminescence behavior

International Nuclear Information System (INIS)

Liang, Chen-Jui; Huang, Kuan-Yu

2017-01-01

A systematic investigation of energy transfers and luminescence behaviors for M x Sr 0.94−x Al 2 O 4 :Eu 0.02 , Dy 0.04 (M=Mg, Ca, Ba; x=0, 0.235, 0.47, 0.705, 0.94) ternary compounds was accomplished. The results demonstrated that six phenomena must be fitted into the energy-transfer mechanisms of the ternary compounds: (1) the optical band-gap energy of Mg 0.94 Al 2 O 4 :Eu 0.02 Dy 0.04 is extremely low and does not allow photoemission; (2) Ca 2+ and Ba 2+ ions are the main hosts when x≥0.47 in Ca x Sr 1−x Al 2 O 4 :Eu 0.02 Dy 0.04 and Ba x Sr 1−x Al 2 O 4 :Eu 0.02 Dy 0.04 , respectively; (3) Eu 3+ ions are the main activator ions in Ca x Sr 1−x Al 2 O 4 :Eu 0.02 Dy 0.04 with x=0.47 and in Ba x Sr 1−x Al 2 O 4 :Eu 0.02 Dy 0.04 with x=0.353−0.705; (4) Sr 2+ and Eu 2+ ions are the main host and activator ions, respectively, when x<0.353 in each ternary compound; (5) energy transfers from the MO phases to the SrO phase because the conduction band energy of SrO is the lowest; and (6) mutual substitution between alkaline-earth ions does not alter the resultant structures’ crystal field and nephelauxetic effects, as determined by measuring their luminescence. Two energy transfer paths were discovered to be possible in CaO–Al 2 O 3 –SrO and BaO–Al 2 O 3 –SrO ternary compounds, and the boundaries determining which path was chosen were the atomic ratios Ca:Sr and Ba:Sr, both approximately 1.6:1 (x=0.353). Because second path increased the energy transferred from the MO band gap to the SrO band gap, the corresponding structure's spectrum emission intensity was approximately 4.3 times higher than that of the SrO−Al 2 O 3 binary compound, and their photoluminescence was thus substantially higher.

Enhanced separation efficiency of photoinduced charges for antimony-doped tin oxide (Sb-SnO{sub 2})/TiO{sub 2} heterojunction semiconductors with varied Sb doping concentration

Energy Technology Data Exchange (ETDEWEB)

Zhang, Zhen-Long [School of Physics and Electronics, Henan University, Kaifeng 475004 (China); Ma, Wen-Hai [School of Physical Education, Henan University, Kaifeng 475004 (China); Mao, Yan-Li, E-mail: ylmao1@163.com [School of Physics and Electronics, Henan University, Kaifeng 475004 (China); Institute for Computational Materials Science, Henan University, Kaifeng 475004 (China)

2014-09-07

In this paper, antimony-doped tin oxide (Sb-SnO{sub 2}) nanoparticles were synthesized with varied Sb doping concentration, and the Sb-SnO{sub 2}/TiO{sub 2} heterojunction semiconductors were prepared with Sb-SnO{sub 2} and TiO{sub 2}. The separation efficiency of photoinduced charges was characterized with surface photovoltage (SPV) technique. Compared with Sb-SnO{sub 2} and TiO{sub 2}, Sb-SnO{sub 2}/TiO{sub 2} presents an enhanced separation efficiency of photoinduced charges, and the SPV enhancements were estimated to be 1.40, 1.43, and 1.99 for Sb-SnO{sub 2}/TiO{sub 2} composed of Sb-SnO{sub 2} with the Sb doping concentration of 5%, 10%, and 15%, respectively. To understand the enhancement, the band structure of Sb-SnO{sub 2} and TiO{sub 2} in the heterojunction semiconductor was determined, and the conduction band offsets (CBO) between Sb-SnO{sub 2} and TiO{sub 2} were estimated to be 0.56, 0.64, and 0.98 eV for Sb-SnO{sub 2}/TiO{sub 2} composed of Sb-SnO{sub 2} with the Sb doping concentration of 5%, 10%, and 15%, respectively. These results indicate that the separation efficiency enhancement is resulting from the energy level matching, and the increase of enhancement is due to the rising of CBO.

Electronic structure, Fermi surface topology and spectroscopic optical properties of LaBaCo{sub 2}O{sub 5.5} compound

Energy Technology Data Exchange (ETDEWEB)

Reshak, A.H. [New Technologies – Research Center, University of West Bohemia, Univerzitni 8, Pilsen 306 14 (Czech Republic); Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia); Al-Douri, Y. [Institute of Nano Electronic Engineering, University Malaysia Perlis, 01000 Kangar, Perlis (Malaysia); Khenata, R. [Laboratoire de Physique Quantique et de Modélisation Mathématique (LPQ3M), Département de Technologie, Université de Mascara, Mascara 29000 (Algeria); Khan, Wilayat; Khan, Saleem Ayaz [New Technologies – Research Center, University of West Bohemia, Univerzitni 8, Pilsen 306 14 (Czech Republic); Azam, Sikander, E-mail: sikander.physicst@gmail.com [New Technologies – Research Center, University of West Bohemia, Univerzitni 8, Pilsen 306 14 (Czech Republic)

2014-08-01

We have investigated the electronic band structure, Fermi surface topology, chemical bonding and optical properties of LaBaCo{sub 2}O{sub 5.5} compound. The first-principle calculations based on density functional theory (DFT) by means of the full-potential linearized augmented plane-wave method were employed. The atomic positions of LaBaCo{sub 2}O{sub 5.5} compound were optimized by minimizing the forces acting on atoms. We employed the local density approximation (LDA), generalized gradient approximation (GGA) and Engel–Vosko GGA (EVGGA) to treat the exchange correlation potential by solving Kohn–Sham equations. Electronic structure and bonding properties are studied throughout the calculation of densities of states, Fermi surfaces and charge densities. Furthermore, the optical properties are investigated via the calculation of the dielectric tensor component in order to characterize the linear optical properties. Optical spectra are analyzed by means of the electronic structure, which provides theoretical understanding of the conduction mechanism of the investigated compound. - Highlights: • DFT-FPLAPW method used for calculating the properties of LaBaCo{sub 2}O{sub 5.5} compound. • This study shows that nature of the compound is metallic. • Crystallographic plane which shows covalent character of O–Co bond. • The optical properties were also calculated and analyzed. • The Fermi surface of LaBaCo{sub 2}O{sub 5.5} is composed of five bands crossing along Γ–Z direction.

Vacuum ultraviolet excited luminescence properties of sol–gel derived GdP5O14:Eu3+ powders

International Nuclear Information System (INIS)

Mbarek, Aïcha; Chadeyron, Geneviève; Boyer, Damien; Avignant, Daniel; Fourati, Mohieddine; Zambon, Daniel

2014-01-01

Sol–gel route has successfully been used to synthesize pure and Eu 3+ doped polycrystalline samples of the GdP 5 O 14 pentaphosphates. The as-prepared samples have structurally been characterized using X-ray diffraction. Optical properties in the vacuum ultraviolet (VUV) of Eu 3+ activated GdP 5 O 14 samples prepared either by sol–gel process or solid-state reaction were investigated at room temperature for comparison. In this GdP 5 O 14 host matrix the P 5 O 14 ultraphosphate groups were proved to exhibit an efficient absorption in the VUV range. The excitation spectra recorded in the VUV-UV spectral region from 120 nm to 350 nm have revealed the presence of Gd 3+ 4f–5d interconfiguration transitions, Gd 3+ –O 2− and Eu 3+ –O 2− charge transfer states(CTS)in addition to intraconfiguration transitions of Gd 3+ ions.Furthermore the Gd 3+ →Eu 3+ energy transfer process was investigated and discussed in the framework of the multiphonon relaxation process. Besides, the GdP 5 O 14 :Eu 3+ phosphor led to a strong red emission under 147/172 nm excitation, so that it can be considered as a promising red phosphor for mercury-free lamps and plasma display panels applications. -- Highlights: • Lanthanide pentaphosphates were synthesized by the sol–gel process. • A broad absorption was evidenced in the VUV range for GdP 5 O 14 :Eu 3+ . • An efficient energy transfer was proved from pentaphosphate lattice to Eu 3+ ions

3,4-Dibromo-2,2,5,5-tetraphenyl-2,5-dihydrofuran

Directory of Open Access Journals (Sweden)

Nadine Seidel

2018-04-01

Full Text Available The crystal structure of the title compound, C28H20Br2O, was solved in the orthorhombic space group P212121 with one molecule in the asymmetric unit. The phenyl rings are nearly planar and inclined at angles of 67.7 (1, 68.8 (1, 79.3 (1 and 62.3 (1° to the plane of the 2,5-dihydrofuran ring. The crystal structure features C—H...π and Br...Br interactions, which connect the molecules to a three-dimensional supramolecular network.

Synthesis and magnetic structure of the YbMn{sub 2}Sb{sub 2} compound

Energy Technology Data Exchange (ETDEWEB)

Morozkin, A.V. [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation)]. E-mail: morozkin@general.chem.msu.ru; Isnard, O. [Institute Laue-Langevin, 6 Rue J. Horowitz, 38042 Grenoble (France); Henry, P. [Institute Laue-Langevin, 6 Rue J. Horowitz, 38042 Grenoble (France); Granovsky, S. [Physics Department, Moscow State University, GSP-2, 119899 Moscow (Russian Federation); Nirmala, R. [Indian Institute of Science, Bangalore (India); Manfrinetti, P. [Dipartimento di Chimica, Universita di Genova, Via Dodecaneso 31, 16146 Genova (Italy)

2006-08-31

A neutron diffraction investigation has been carried out on the trigonal La{sub 2}O{sub 3}-type (hP5, space group P3-bar ml, No. 164; also CaAl{sub 2}Si{sub 2}-type) YbMn{sub 2}Sb{sub 2} intermetallic. A two-step synthesis route has been tried in this work, and successfully utilised to prepare single phase samples of this compound. This study shows that YbMn{sub 2}Sb{sub 2} presents antiferromagnetic ordering below 120K. The magnetic structure of this intermetallic consists of antiferromagnetically coupled magnetic moments of the manganese atoms, in the Mn1 (1/3, 2/3, Z{sub Mn}) and Mn2 (2/3, 1/3, 1-Z{sub Mn}) sites; the direction of magnetic moments of manganese atoms forming a {phi} and a {theta} angle, respectively with the X- and the Z-axis. At 4K the magnetic moment of the Mn1 atom is {mu}{sub Mn}=3.6(1) {mu}{sub B}, with {phi}=0{sup o} and {theta}=62(4){sup o}, whilst the Mn2 atom has a magnetic moment {mu}{sub Mn}=3.6(1) {mu}{sub B}, with {phi}=0{sup o} and {theta}=242(4){sup o}. On the other hand, in this compound no local moment was detected on the Yb site.

Thermomechanical Properties of Sb2O3-TeO2-V2O5 Glassy Systems: Thermal Stability, Glass Forming Tendency and Vickers Hardness

Science.gov (United States)

Souri, Dariush; Torkashvand, Ziba

2017-04-01

Three-component 40TeO2-(60- x)V2O5- xSb2O3 glasses with 0 ≤ x ≤ 10 (in mol.%) were obtained by the rapid melt-quenching method. These glasses were studied with respect to some mechanical properties with the goal of obtaining information about their structure. The Vickers hardness test was employed to obtain Vickers micro-hardness ( H V) at two different loads, which was within the range of 13.187-17.557 GPa for a typical 0.1 HV (0.9807 N) load. In addition, theoretical micro-hardness ( H) was investigated and compared with experimental H V, showing the elevating trend with increase of Sb2O3 content, as for H V. Furthermore, differential scanning calorimetry (DSC) was employed within the range of 150-500°C at heating rates of φ = 3 K/min, 6 K/min, 9 K/min, 10 K/min, and 13 K/min. In this work, thermal stability ( T s = T cr - T x) and glass forming tendency ( K gl) were measured and reported for these glasses to determine the relationship between the chemical composition and the thermal stability, in order to interpret the structure of glass. Generally, from the ascertained outputs [analysis of mechanical data, titration study, the values of reduced fraction of vanadium ions ( C V) and oxygen molar volume ( V_{{O}}^{*} )], it was found that the micro-hardness had an increasing trend with increasing the Sb2O3 content. Among the studied glasses, the sample with x = 8 had a higher average micro-hardness value, the highest average thermal stability and glass forming tendency with respect to the other samples, which makes it a useful material (owning very good resistance against thermal attacks) for device manufacturing.

Hydrothermal-precipitation preparation of CdS@(Er3+:Y3Al5O12/ZrO2) coated composite and sonocatalytic degradation of caffeine.

Science.gov (United States)

Huang, Yingying; Wang, Guowei; Zhang, Hongbo; Li, Guanshu; Fang, Dawei; Wang, Jun; Song, Youtao

2017-07-01

Here, we reported a novel method to dispose caffeine by means of ultrasound irradiation combinated with CdS@(Er 3+ :Y 3 Al 5 O 12 /ZrO 2 ) coated composite as sonocatalyst. The CdS@(Er 3+ :Y 3 Al 5 O 12 /ZrO 2 ) was synthesized via hydrothermal-precipitation method and then characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX) and UV-vis diffuse reflectance spectra (DRS). After that, the sonocatalytic degradation of caffeine in aqueous solution was conducted adopting CdS@(Er 3+ :Y 3 Al 5 O 12 /ZrO 2 ) and CdS@ZrO 2 coated composites as sonocatalysts. In addition, some influencing factors such as CdS and ZrO 2 molar proportion, caffeine concentration, ultrasonic irradiation time, sonocatalyst dosage and addition of several inorganic oxidants on sonocatalytic degradation of caffeine were investigated by using UV-vis spectra and gas chromatograph. The experimental results showed that the presence of Er 3+ :Y 3 Al 5 O 12 could effectively improve the sonocatalytic degradation activity of CdS@ZrO 2 . To a certain extent some inorganic oxidants can also enhance sonocatalytic degradation of caffeine in the presence of CdS@(Er 3+ :Y 3 Al 5 O 12 /ZrO 2 ). The best sonocatalytic degradation ratio (94.00%) of caffeine could be obtained when the conditions of 5.00mg/L caffeine, 1.00g/L prepared CdS@(Er 3+ :Y 3 Al 5 O 12 /ZrO 2 ), 10.00mmol/LK 2 S 2 O 8 , 180min ultrasonic irradiation (40kHz frequency and 50W output power), 100mL total volume and 25-28°C temperature were adopted. It seems that the method of sonocatalytic degradation caused by CdS@(Er 3+ :Y 3 Al 5 O 12 /ZrO 2 ) displayspotentialadvantages in disposing caffeine. Copyright © 2017 Elsevier B.V. All rights reserved.

Current-voltage characteristics of SnO2-Co3O4-Cr2O3-Sb2O5 ceramics

International Nuclear Information System (INIS)

Aguilar-Martinez, J A; Glot, A B; Gaponov, A V; Hernandez, M B; Guerrero-Paz, J

2009-01-01

The effect of mechanical treatment in a planetary mill on the microstructure and electrical properties of tin dioxide based varistor ceramics in the system SnO 2 -Co 3 O 4 -Cr 2 O 3 -Sb 2 O 5 sintered in the range 1150-1450 0 C was studied. The mechanical treatment leads to an increase in shrinkage, decrease in porosity, decrease in sample diameter, change in colour of the sintered samples from grey to black and enhancement of nonlinearity. For the sample sintered at 1350 0 C the mechanical treatment enhances the nonlinearity coefficient from 11 to 31 and decreases the electric field E 1 (at 10 -3 A cm -2 ) from 3500 to 2800 V cm -1 . The observed changes in physical properties are explained in terms of an additional size reduction of oxide particles and a better mixing of oxide powder followed by the formation of potential barriers at the grain boundaries throughout the whole sample. In spite of the low porosity, the low-field electrical conductivity of mechanically treated ceramics is significantly increased with the growth of relative humidity. A higher humidity sensitivity is found for mechanically treated ceramics with higher barrier height and higher nonlinearity coefficient.

Syntheses and structural characterization of vanado-tellurites and vanadyl-selenites: SrVTeO{sub 5}(OH), Cd{sub 2}V{sub 2}Te{sub 2}O{sub 11}, Ca{sub 3}VSe{sub 4}O{sub 13}·H{sub 2}O and Ba{sub 2}VSe{sub 3}O{sub 10}

Energy Technology Data Exchange (ETDEWEB)

Konatham, Satish; Vidyasagar, Kanamaluru, E-mail: kvsagar@iitm.ac.in

2017-05-15

Four new quaternary vanado-tellurites and vanadyl-selenites, namely, SrVTeO{sub 5}(OH)(1), Cd{sub 2}V{sub 2}Te{sub 2}O{sub 11}(2), Ca{sub 3}VSe{sub 4}O{sub 13}·H{sub 2}O(3) and Ba{sub 2}VSe{sub 3}O{sub 10}(4) have been synthesized and structurally characterized by single crystal X-ray diffraction. The oxidation state of vanadium is +5 in tellurites 1 and 2 and +4 in selenites 3 and 4. The structures of SrVTeO{sub 5}(OH)(1) and Cd{sub 2}V{sub 2}Te{sub 2}O{sub 11}(2) compounds consist of (VTeO{sub 5}(OH)){sup 2-} and (V{sub 2}Te{sub 2}O{sub 11}){sup 4-}anionic chains respectively, which are built from tetrahedral VO{sub 4} and disphenoidal TeO{sub 4} moieties. Similarly the structures of Ca{sub 3}VSe{sub 4}O{sub 13}·H{sub 2}O(3) and Ba{sub 2}VSe{sub 3}O{sub 10}(4) respectively contain (VSe{sub 2}O{sub 7}){sup 2-} and (VSe{sub 3}O{sub 10}){sup 4-} anionic chains, which are made up of octahedral VO{sub 6} and pyramidal SeO{sub 3} units. Compounds 1 and 3 have been characterized by thermogravimetric and infrared spectroscopic methods. Compounds 1 and 2 are wide band gap semiconductors. - Graphical abstract: Ca{sub 3}VSe{sub 4}O{sub 13}·H{sub 2}O and Ba{sub 2}VSe{sub 3}O{sub 10} compounds contain (VSe{sub 2}O{sub 7}){sup 2-} and (VSe{sub 3}O{sub 10}){sup 4-} chains. - Highlights: • Four new vanado-tellurites and vanadyl-selenites are synthesized. • Their structural features are different. • The vanado-tellurites are wide band gap semiconductors.

Adsorption of Cs(I), Sr(II), Eu(III), Co(II) and Cd(II) by Al2O3

International Nuclear Information System (INIS)

Shiao, S.Y.; Egozy, Y.; Meyer, R.E.

1981-01-01

Adsorption of Cs(I), Sr(II), Eu(III), Co(II) and Cd(II) by Al 2 O 3 was carried out over a wide range of NaCl concentration and solution pH. In the medium pH region (pH 5 to 9), adsorption depends strongly on pH and less on salt concentration. However, in the high pH region (pH above 9), the salt dependence of the distribution coefficient becomes important. (author)

Facile fabrication of core–shell ZnO/Bi{sub 0.5}Sb{sub 1.5}Te{sub 3} nanorods: Enhanced photoluminescence through electron charge

Energy Technology Data Exchange (ETDEWEB)

Shen, Shengfei; Gao, Hongli [School of Materials Science & Engineering, Beihang University, Beijing 100191 (China); Deng, Yuan, E-mail: dengyuan@buaa.edu.cn [School of Materials Science & Engineering, Beihang University, Beijing 100191 (China); Wang, Yao [School of Materials Science & Engineering, Beihang University, Beijing 100191 (China); Qu, Shengchun, E-mail: qsc@semi.ac.cn [Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)

2016-01-15

Graphical abstract: - Highlights: • The Bi{sub 0.5}Sb{sub 1.5}Te{sub 3}/ZnO core–shells prepared by combining a facile hydrothermal growth and magnetron sputtering approach. • The light absorption and photoluminescence emission of the ZnO and the Bi{sub 0.5}Sb{sub 1.5}Te{sub 3}/ZnO core–shells are investigated. • The core–shell structure reveals a simultaneous novelty enhancement of the photoluminescence emission in the UV and visible range. • The mechanism for the PL simultaneous enhancement is described. - Abstract: Surface decoration techniques are emerging as promising strategy to improve the optical properties of the ZnO based materials. The core–shell ZnO/Bi{sub 0.5}Sb{sub 1.5}Te{sub 3} nanorods were grown on a FTO substrate through a facile hydrothermal and magnetron sputtering combined approach. The microstructure of the core–shell nanorod arrays were investigated by the X-ray diffraction (XRD), a field emission Scanning electron microscopy (SEM) and high resolution transmission electron microscope (HTEM). The optical properties of the core–shell nanorod arrays were investigated through the diffuse reflectance absorption spectra and photoluminescence emission. The visible light absorption and especially the photoluminescence emission of the ZnO nanorods are enhanced markedly with the Bi{sub 0.5}Sb{sub 1.5}Te{sub 3} grains coating the ZnO nanorods through the electron charge.

Investigations on the electrodeposition behaviors of Bi0.5Sb1.5Te3 thin film from nitric acid baths

International Nuclear Information System (INIS)

Li Feihui; Huang Qinghua; Wang Wei

2009-01-01

The electrochemical reduction process of Bi 3+ , HTeO 2 + , Sb III and their mixtures in nitric acid medium was investigated by means of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements. The reduction products electrodeposited at various potentials were examined using X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS). The results show that cathodic process in the nitric acid solution containing Bi 3+ , HTeO 2 + and Sb III involves the following reduction reactions in different polarizing potential ranges: In low polarizing potential ranges, Te 0 is formed firstly on the electrode surface through the electrochemical reduction of HTeO 2 + ; with the negative shift of the cathodic polarizing potential, the reduction reaction of Bi 3+ with Te 0 to form Bi 2 Te 3 takes place; when the cathodic polarizing potential is negative enough, Bi 3+ and Sb III react with Te 0 to form Bi 0.5 Sb 1.5 Te 3 . The results indicate that Bi 0.5 Sb 1.5 Te 3 films can be fabricated by controlling the electrodepositing potential in a proper high potential ranges.

N-[(2S-4-Chloro-2-(l-menthyloxy-5-oxo-2,5-dihydro-3-furyl]-l-alanine

Directory of Open Access Journals (Sweden)

Kai Yang

2009-05-01

Full Text Available The title compound, C17H26ClNO5, was prepared via a tandem asymmetric Michael addition–elimination reaction of (5S-3,4-dichloro-5-(l-menthyloxyfuran-2(5H-one and l-alanine in the presence of potassium hydroxide. The five-membered furanone ring is approximately planar while the six-membered menthyloxy ring adopts a chair conformation. The crystal packing is stabilized by intermolecular O—H...O and N—H...O hydrogen bonds.

2-Amino-5-bromopyridinium hydrogen succinate

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Hoong-Kun Fun

2010-03-01

Full Text Available In the title compound, C5H6BrN2+·C4H5O4−, the pyridine N atom of the 2-amino-5-bromopyridine molecule is protonated. The protonated N atom and the amino group are linked via N—H...O hydrogen bonds to the carboxylate O atoms of the singly deprotonated succinate anion. The hydrogen succinate anions are linked via O—H...O hydrogen bonds. A weak intermolecular C—H...O hydrogen bond is also observed.

The equilibrium diagram and some properties of alloys Gd5Sb3-Tb5Sb3 system

International Nuclear Information System (INIS)

Azizov, Yu.S.; Abulkhaev, V.D.; Ganiev, I.N.

2001-01-01

The purpose of present work is investigation equilibrium diagram of Gd 5 Sb 3 -Tb 5 Sb 3 system in total range of concentrations. Equilibrium diagram of Gd 5 Sb 3 -Tb 5 Sb 3 system investigated by methods of difference-thermal, roentgen-phase and metallographic analyses. For the first time on the base of difference-thermal, roentgen-phase and metallographic analyses was formed the equilibrium diagram of Gd 5 Sb 3 -Tb 5 Sb 3 system. Was determined the cristal-chemical parameters of solid solutions with general formula Gd x Tb 5 - x Sb 3

Crystal structures of the solid solutions Na3Zn0.912Cd0.088B5O10 and Na3Zn0.845Mg0.155B5O10

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Xue-An Chen

2017-11-01

Full Text Available Two new pentaborates, trisodium zinc cadmium pentaborate, Na3Zn0.912Cd0.088B5O10, and trisodium zinc magnesium pentaborate, Na3Zn0.845Mg0.155B5O10, have been synthesized by high-temperature solution reactions at 1023 K. Their crystal structures were determined by single-crystal X-ray diffraction. Both solid solutions crystallize in the orthorhombic form of the parent compound Na3ZnB5O10 (space group type Pbca, Z = 8 and contain the double ring [B5O10]5− anion composed of one BO4 tetrahedron and four BO3 triangles as the basic structural motif. The anions are bridged by tetrahedrally coordinated and occupationally disordered M2+ (M = Zn/Cd, Zn/Mg cations via common O atoms to form [MB5O10]n3n− layers. The intralayer intersecting channels and the interlayer voids are occupied by Na+ cations to balance the charge.

Sol–gel synthesis of long-lasting phosphors CdSiO3: Mn2+, RE3+ (RE = Tb, Eu, Nd) and luminescence mechanism research

International Nuclear Information System (INIS)

Qu, Xiaofei; Cao, Lixin; Liu, Wei; Su, Ge; Wang, Pingping; Schultz, Isabel

2012-01-01

Highlights: ► New long-lasting CdSiO 3 : Mn 2+ , RE 3+ (RE = Tb, Eu, Nd) phosphors were synthesized by a sol–gel method. ► The afterglow performance of the CdSiO 3 : Mn 2+ , Eu 3+ phosphor was the best. ► The role of RE 3+ co-doped into the CdSiO 3 : Mn 2+ matrix was discussed in this paper. -- Abstract: Mn 2+ and RE 3+ (RE = Tb, Eu, Nd) co-doped CdSiO 3 orange phosphors were prepared at 1050 °C by a sol–gel method. The phase and crystallinity of the synthesized materials were investigated by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The luminescence characteristics were analyzed using photoluminescence (PL) spectra, afterglow decay curves, long-lasting phosphorescence spectra, and thermoluminescence (TL) spectra. Due to the difference in co-doped rare earth ionic radii, it varied greatly in trap density and trap depth caused by the different defects deriving from RE 3+ ions co-doping into the CdSiO 3 : Mn 2+ host. The afterglow intensity and time for these samples increased as follows: CdSiO 3 : Mn 2+ 0.2%, Nd 3+ 0.8% 3 : Mn 2+ 0.4%, Tb 3+ 0.8% 3 : Mn 2+ 0.4%, Eu 3+ 0.3%. CdSiO 3 : Mn 2+ 0.4%, Eu 3+ 0.3% had the best afterglow properties, which could be due to the proper traps formed by Eu 3+ ions co-doping into the host. The role of RE 3+ co-doped into the CdSiO 3 : Mn 2+ matrix and the possible long-lasting phosphorescence process was also discussed in this paper.

Electrochemical oxidation of 2,4,5-trichlorophenoxyacetic acid by metal-oxide-coated Ti electrodes.

Science.gov (United States)

Maharana, Dusmant; Xu, Zesheng; Niu, Junfeng; Rao, Neti Nageswara

2015-10-01

Electrochemical oxidation of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) over metal-oxide-coated Ti anodes, i.e., Ti/SnO2-Sb/Ce-PbO2, Ti/SnO2-Sb and Ti/RuO2, was examined. The degradation efficiency of over 90% was attained at 20 min at different initial concentrations (0.5-20 mg L(-1)) and initial pH values (3.1-11.2). The degradation efficiencies of 2,4,5-T on Ti/SnO2-Sb/Ce-PbO2, Ti/SnO2-Sb and Ti/RuO2 anodes were higher than 99.9%, 97.2% and 91.5% at 30 min, respectively, and the respective total organic carbon removal ratios were 65.7%, 54.6% and 37.2%. The electrochemical degradation of 2,4,5-T in aqueous solution followed pseudo-first-order kinetics. The compounds, i.e., 2,5-dichlorohydroquinone and 2,5-dihydroxy-p-benzoquinone, have been identified as the main aromatic intermediates by liquid chromatography-mass spectrometry. The results showed that the energy efficiencies of 2,4,5-T (20 mg L(-1)) degradation with Ti/SnO2-Sb/Ce-PbO2 anode at the optimal current densities from 2 to 16 mA cm(-2) ranged from 8.21 to 18.73 kWh m(-3). Copyright © 2015 Elsevier Ltd. All rights reserved.

Performance PtSnRh electrocatalysts supported on carbon-Sb{sub 2}O{sub 5}.SbO{sub 2} for the electro-oxidation of ethanol, prepared by an alcohol-reduction process; Desempenho de eletrocatalisadores PtSnRh suportados em carbono-Sb{sub 2}O{sub 5}.SnO{sub 2} para a oxidacao eletroquimica do etanol, preparados pelo metodo de reducao por alcool

Energy Technology Data Exchange (ETDEWEB)

Castro, Jose Carlos

2013-07-01

PtSnRh electrocatalysts supported on carbon-Sb{sub 2}O{sub 5}.SnO{sub 2}, with metal loading of 20 wt%, were prepared by an alcohol-reduction process, using H{sub 2}PtCl{sub 6}.6H{sub 2}O (Aldrich), RhCl{sub 3}.xH{sub 2}O (Aldrich) and SnCl{sub 2}.2H{sub 2}O (Aldrich), as source of metals; Sb{sub 2}O{sub 5}.SnO{sub 2} (ATO) and carbon Vulcan XC72, as support; and ethylene glycol as reducing agent. The electrocatalysts obtained were characterized physically by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The diffractograms showed which PtSnRh/C-ATO electrocatalysts had FCC structure of Pt and Pt alloys, besides several peaks associated with SnO{sub 2} and ATO. The average sizes of crystallites were between 2 and 4 nm. TEM micrographs showed a good distribution of the nanoparticles on the support. The average sizes of particles were between 2 and 3 nm, with good agreement for the average size of the crystallites. The performances of the electrocatalysts were analyzed by electrochemical techniques and in real conditions of operation using single direct ethanol fuel cell. In the chronoamperometry at 50 deg C, the electrocatalysts with carbon (85 wt%) and ATO (15 wt%) support, showed the best activity, and the atomic proportions which achieved the best results were PtSnRh(70:25:05) e (90:05:05). PtSnRh(70:25:05)/85C+15ATO electrocatalysts showed the best performance in a direct ethanol fuel cell. (author)

Electrical conduction of glasses in the system Fe2O3-Sb2O3-TeO2; Fe2O3-Sb2O3-TeO2 kei garasu no denki dendo

Energy Technology Data Exchange (ETDEWEB)

Qiu, Honghua; Mori, H; Sakata, H; Hirayama, T [Tokai Univ., Tokyo (Japan). Faculty of Engineering

1995-01-01

In this study, taking into consideration that TeO2 is a component of the glass network and Sb2O3 shows the redox effect in the glasses reducing its possibility of transformation of Sb{sup 3+} to Sb{sup 5+} as well as glass basicity, highly conductive tellurite based glasses have been prepared by the press-quenching method selecting the Fe2O3-Sb2O3-TeO2 system, and the electroconductive mechanism of the glasses has been examined by measuring its D.C. conductivity {sigma}. Part of the obtained information is as follows; the glass formation range of the Fe2O3-Sb2O3-TeO2 system has been 0 {le} Fe2O3 {le} 15mol%, 0 {le} Sb2O3 {le} 18mol% and 78 {le} TeO2 {le} 100mol% and about 15mol% of the additional amount of Fe2O3 has been the limit of glass formation. As the amount of Fe2O3 has increased, C{sub Fe} has also increased and with this, the linear electroconductivity of the glasses has increased from 1.86 {times} 10{sup -7}S{center_dot}cm{sup -1} to 1.62 {times} 10{sup -6}S{center_dot}cm{sup -1} and the glasses have been confirmed as the n-type semiconductor. The factor determining {sigma} of the glasses has been C{sub Fe} which has increased as the amount of Fe2O3 has increased. 34 refs., 8 figs., 2 tabs.

Yellow light emission from Ta2O5:Er, Eu, Ce thin films deposited using a simple co-sputtering method

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K. Miura

2015-01-01

Full Text Available Erbium, europium, and cerium co-doped tantalum oxide (Ta2O5:Er, Eu, Ce thin films were prepared using a simple co-sputtering method, and yellow light emission was observed by the naked eye from a sample annealed at 900 °C for 20 min. The hexagonal Ta2O5 phase is very important, but the hexagonal CeTa7O19 phase should be avoided to obtain strong yellow light emission from Ta2O5:Er, Eu, Ce films. The co-sputtered films can be used as high-refractive-index and yellow-light-emitting materials of autocloned photonic crystals that can be applied to novel light-emission devices, and they will also be used as anti-reflection and down-conversion layers toward high-efficiency silicon solar cells.

Unprecedented connection mode of [V{sub 16}Sb{sub 4}O{sub 42}(H{sub 2}O)]{sup 8-} cluster anions by Mn{sup 2+} centered complexes. Solvothermal synthesis and properties of {[Mn(teta)]_4V_1_6Sb_4O_4_2(H_2O)}{sub n}.[(H{sub 2}O){sub 12}]{sub n}

Energy Technology Data Exchange (ETDEWEB)

Rasmussen, Maren; Naether, Christian; Bensch, Wolfgang [Institute of Inorganic Chemistry, Christian-Albrechts-University of Kiel (Germany); Leusen, Jan van; Koegerler, Paul [Institute of Inorganic Chemistry, RWTH Aachen University, Aachen (Germany)

2017-11-17

The new compound {[Mn(teta)]_4V_1_6Sb_4O_4_2}{sub n}.[(H{sub 2}O){sub 12}]{sub n} (teta = triethylenetetraamine) was synthesized under solvothermal conditions. The crystal structure features the high nuclearity [V{sub 16}{sup IV}Sb{sub 4}{sup III}O{sub 42}(H{sub 2}O)]{sup 8-} cluster anion, which consists of two rings composed of 8 edge-sharing VO{sub 5} polyhedra. The rings are perpendicular to each other generating four niches, which are occupied by two VO{sub 5} pyramids and two handle-like Sb{sub 2}O{sub 5} units. The two unique anions are each surrounded by eight Mn{sup 2+} centered complexes via Mn-O{sub term}-V bonds. Such an expansion has never been observed in heterometal polyoxovanadate chemistry. The connection mode between cluster anions and complex cations generates two individual layers stacked onto each other. Between the layers weak Sb..O contacts are observed. The crystal water molecules are mainly located in the empty space between the layers. Upon heating H{sub 2}O molecules are removed, while the crystal structure remains intact. The magnetic behavior is dominated by strong antiferromagnetic exchange interactions between the central V{sup 4+} ions, while the interaction between the cluster anion and central Mn{sup 2+} ions is significantly less pronounced. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

The abatement of indigo carmine using active chlorine electrogenerated on ternary Sb2O5-doped Ti/RuO2-ZrO2 anodes in a filter-press FM01-LC reactor

International Nuclear Information System (INIS)

Palma-Goyes, R.E.; Vazquez-Arenas, J.; Torres-Palma, R.A.; Ostos, C.; Ferraro, F.; González, I.

2015-01-01

Dimensionally Stable Anodes (DSA) of Sb 2 O 5 -doped Ti/RuO 2 -ZrO 2 are prepared by the Pechini method to perform the degradation of indigo carmine (IC) under conditions similar to textile wastewater effluents. XRD results along with Rietveld refinement reveal that the co-deposited phases on the DSA exhibit a tetragonal crystal structure (P4/mmm) for RuO 2 and monoclinic structure (P2/m) for ZrO 2 . Degradation tests conducted in solutions containing 0.64 mM IC and 0.05 M NaCl using a filter-press reactor (FM01-LC) show that the degradation rate is faster and more efficient at 200 A m −2 with a flow rate of 5 L min −1 , although the energy consumption is moderately higher. Under this condition, the pollutant is efficiently removed, and converted to aliphatic acid compounds of low molecular weight, as indicated by 90 % Chemical Oxygen Demand (COD), 22 % Total Organic Carbon (TOC) elimination, along with an Average Oxidation State (AOS) value equal to 3.0. The energy consumptions revealed that it is feasible to carry out the IC degradation under reasonable operating costs. Topological and Natural Bond Orbital (NBO) analyses are computed using density functional theory (DFT), and combined with experimental results to propose a reaction pathway for IC abatement

Synthesis and crystal structure of the rare earth borogermanate EuGeBO{sub 5}

Energy Technology Data Exchange (ETDEWEB)

Chi, Yang; Zhuang, Yan; Guo, Sheng-Ping [Yangzhou Univ., Jiangsu (China). College of Chemistry and Chemical Engineering

2017-03-01

The synthesis and crystal structure of the rare earth borogermanate EuGeBO{sub 5} are reported. It is synthesized by high-temperature solid-state reaction and crystallizes in the monoclinic space group P2{sub 1}/c (no. 14) with the unit cell parameters a=4.8860(5), b=7.5229(8), c=9.9587(10) Aa, and β=91.709(3) . Its crystal structure features a polyanion-type layer (GeBO{sub 5}){sup 3-} constructed by BO{sub 4} and GeO{sub 4} tetrahedra connected alternatingly. Eu{sup 3+} ions are located in cavities and are coordinated by eight O atoms. Various structures of the related compounds REMM'O{sub 5} (RE=rare earth metal; M=Si, Ge, and Sn; M'=B, Al, and Ga) are also discussed.

Lineage determination of CD7+ CD5- CD2- and CD7+ CD5+ CD2- lymphoblasts: studies on phenotype, genotype, and gene expression of myeloperoxidase, CD3 epsilon, and CD3 delta.

Science.gov (United States)

Yoneda, N; Tatsumi, E; Teshigawara, K; Nagata, S; Nagano, T; Kishimoto, Y; Kimura, T; Yasunaga, K; Yamaguchi, N

1994-04-01

The gene expression of myeloperoxidase (MPO), CD3 epsilon, and CD3 delta molecules, the gene rearrangement of T-cell receptor (TCR) delta, gamma, and beta and immunoglobulin heavy (IgH) chain, and the expression of cell-surface antigens were investigated in seven cases of CD7+ CD5- CD2- and four cases of CD7+ CD5+ CD2- acute lymphoblastic leukemia or lymphoblastic lymphoma (ALL/LBL) blasts, which were negative for cytochemical myeloperoxidase (cyMPO). More mature T-lineage blasts were also investigated in a comparative manner. In conclusion, the CD7+ CD5- CD2- blasts included four categories: undifferentiated blasts without lineage commitment, T-lineage blasts, T-/myeloid lineage blasts, and cyMPO-negative myeloblasts. The CD7+ CD5+ CD2- blasts included two categories; T-lineage and T-/myeloid lineage blasts. The 11 cases were of the germ-line gene (G) for TCR beta and IgH. Four cases were G for TCR delta and TCR gamma. The others were of the monoclonally rearranged gene (R) for TCR delta and G for TCR gamma or R for both TCR delta and TCR gamma. The expression or in vitro induction of CD13 and/or CD33 antigens correlated with the immaturity of these neoplastic T cells, since it was observed in all 11 CD7+ CD5- CD2- and CD7+ CD5+ CD2-, and some CD7+ CD5+ CD2+ (CD3- CD4- CD8-) cases, but not in CD3 +/- CD4+ CD8+ or CD3+ CD4+ CD8- cases. CD3 epsilon mRNA, but not CD3 delta mRNA, was detected in two CD7+ CD5- CD2- cases, while mRNA of neither of the two CD3 molecules was detected in the other tested CD7+ CD5- CD2- cases. In contrast, mRNA of both CD3 epsilon and CD3 delta were detected in all CD7+ CD5+ CD2- cases, indicating that CD7+ CD5- CD2- blasts at least belong to T-lineage. The blasts of two CD7+ CD5- CD2- cases with entire germ-line genes and without mRNA of the three molecules (MPO, CD3 epsilon, and CD3 delta) were regarded as being at an undifferentiated stage prior to their commitment to either T- or myeloid-lineage. The co-expression of the genes of MPO

Synthesis and effect of Ce and Mn co-doping on photoluminescence characteristics of Ca6AlP5O20:Eu novel phosphors.

Science.gov (United States)

Shinde, K N; Dhoble, S J

2013-01-01

A series of Ca6AlP5O20 doped with rare earths (Eu and Ce) and co-doped (Eu, Ce and Eu,Mn) were prepared by combustion synthesis. Under Hg-free excitation, Ca6AlP5O20:Eu exhibited Eu(2+) (486 nm) emission in the blue region of the spectrum and under near Hg excitation (245 nm), Ca6AlP5O20:Ce phosphor exhibited Ce(3+) emission (357 nm) in the UV range. Photoluminescence (PL) peak intensity increased in Ca6AlP5O20:Eu,Ce and Ca6AlP5O20:Eu, Mn phosphors due to co-activators of Ce(3+) and Mn(2+) ions. As a result, these ions played an important role in PL emission in the present matrix. Ca6AlP5O20:Eu, Ce and Ca6AlP5O20:Eu, Mn phosphors provided energy transfer mechanisms via Ce(3+) → Eu(2+) and Eu(2+) → Mn(2+), respectively. Eu ions acted as activators and Ce ions acted as sensitizers. Ce emission energy was well matched with Eu excitation energy in the case of Ca6AlP5O20:Eu, Ce and Eu ions acted as activators and Mn ions acted as sensitizers in Ca6AlP5O20:Eu, Mn. This study included synthesis of new and efficient phosphate phosphors. The impact of doping and co-doping on photoluminescence properties and energy transfer mechanisms were investigated and we propose a feasible interpretation. Copyright © 2012 John Wiley & Sons, Ltd.

Magnetic structure and physical properties of the multiferroic compound PrMn{sub 2}O{sub 5}

Energy Technology Data Exchange (ETDEWEB)

Doubrovsky, C. [Laboratoire de Physique des Solides, Universite Paris-Sud, CNRS-UMR 8502, 91405 Orsay Cedex (France); Andre, G. [Laboratoire Leon Brillouin, CEA-CNRS UMR 12, 91191 Gif-sur-Yvette Cedex (France); Bouquet, F. [Laboratoire de Physique des Solides, Universite Paris-Sud, CNRS-UMR 8502, 91405 Orsay Cedex (France); Elkaim, E. [Soleil Synchrotron, 91191 Gif-sur-Yvette Cedex (France); Li, M.; Greenblatt, M. [Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 (United States); Foury-Leylekian, P., E-mail: pascale.foury@u-psud.fr [Laboratoire de Physique des Solides, Universite Paris-Sud, CNRS-UMR 8502, 91405 Orsay Cedex (France)

2012-06-01

RMn{sub 2}O{sub 5} (R=lanthanide, Bi, Y) multiferroic compounds are intensively studied for their potential application in the spintronic field. In these systems, the key issue is to understand the origin of the strong coupling between the ferroelectric and magnetic orders and to investigate the influence of the nature of the R ions in this coupling. While the phase diagram of RMn{sub 2}O{sub 5} compounds with small R size is well established, this of large R size compounds is missing due to the lack of samples originating with difficulties of synthesis. We present in this paper the first investigation of the thermodynamic, structural and magnetic properties of high quality polycrystalline PrMn{sub 2}O{sub 5} samples. Our work shows that PrMn{sub 2}O{sub 5} presents two magnetic transitions corresponding to commensurate magnetic orderings. We also evidence a weak lattice effect coupled to the magnetic order. Our results point out that the physical properties of PrMn{sub 2}O{sub 5} differ from those of the parent compounds with magnetic R ions.

Rethinking Sensitized Luminescence in Lanthanide Coordination Polymers and MOFs: Band Sensitization and Water Enhanced Eu Luminescence in [Ln(C15H9O5)3(H2O)3]n (Ln = Eu, Tb).

Science.gov (United States)

Einkauf, Jeffrey D; Kelley, Tanya T; Chan, Benny C; de Lill, Daniel T

2016-08-15

A coordination polymer [Ln(C15H9O9)3(H2O)3]n (1-Ln = Eu(III), Tb(III)) assembled from benzophenonedicarboxylate was synthesized and characterized. The organic component is shown to sensitize lanthanide-based emission in both compounds, with quantum yields of 36% (Eu) and 6% (Tb). Luminescence of lanthanide coordination polymers is currently described from a molecular approach. This methodology fails to explain the luminescence of this system. It was found that the band structure of the organic component rather than the molecular triplet state was able to explain the observed luminescence. Deuterated (Ln(C15H9O9)3(D2O)3) and dehydrated (Ln(C15H9O9)3) analogues were also studied. When bound H2O was replaced by D2O, lifetime and emission increased as expected. Upon dehydration, lifetimes increased again, but emission of 1-Eu unexpectedly decreased. This reduction is reasoned through an unprecedented enhancement effect of the compound's luminescence by the OH/OD oscillators in the organic-to-Eu(III) energy transfer process.

Ge{sup 4+}, Eu{sup 3+}-codoped Y{sub 2}SiO{sub 5} as a novel red phosphor for white LED applications

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yan; Dong, Yuanyuan [School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418 (China); Wei, Bo [School of Chemistry and Materials Engineering, Changshu Institute of Technology, Changshu 215500 (China); Xu, Jiayue

2017-05-15

The phosphors Y{sub 2}SiO{sub 5}: Ge{sup 4+}, Eu{sup 3+} were synthesized by solid state reaction method assisted by flux, and have been characterized by X-ray powder diffraction and fluorescence spectrometer. The results showed that the phosphors can be effectively excited by near-UV (394 nm), and the major peak is located at 611 nm ascribed to the electric-dipole {sup 5}D{sub 0} → {sup 7}F{sub 2} transition of Eu{sup 3+}, the critical quenching concentration of Eu{sup 3+} in the phosphor is determined to be 15 mol% and the critical transfer distance is calculated as 8.90 Aa. Co-doping Y{sub 2}SiO{sub 5}: Eu{sup 3+} with Ge{sup 4+} helps to improve the luminescence intensity and color purity. The red emission of the phosphor under 394 nm excitation shows a good chromaticity index (0.652, 0.347) compared to commercial red phosphors Y{sub 2}O{sub 2}S: Eu{sup 3+} (0.631, 0.350). The quantum efficiency of the Y{sub 2}Si{sub 0.97}O{sub 5}: 0.03Ge{sup 4+}, 0.15Eu{sup 3+}phosphor under 394 nm excitation is estimated to be 45.24%. It can be concluded that efficient red light emitting diodes were fabricated using Ge{sup 4+}, Eu{sup 3+} co-doped phosphor based on near ultraviolet(NUV) excited LED lights. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

A three-dimensional coordination polymer based on 1,2,3-triazole-4,5-dicarboxylic acid (H{sub 3}tda): ([Cd{sub 12}(tda){sub 8}(H{sub 2}O){sub 11}] · (H{sub 2}O)6.25){sub n}

Energy Technology Data Exchange (ETDEWEB)

Zhou, Xin-Hui, E-mail: iamxhzhou@njupt.edu.cn; Chen, Qiang [Nanjing University of Posts and Telecommunications, Key Laboratory for Organic Electronics and Information Displays and Institute of Advanced Materials, National Jiangsu Syngerstic Innovation Center for Advanced Materials (SICAM) (China)

2017-03-15

The title coordination polymer ([Cd{sub 12}(tda){sub 8}(H{sub 2}O){sub 11}] · (H{sub 2}O){sub 6.25}){sub n} (H{sub 3}tda = 1,2,3-triazole-4,5-dicarboxylic acid), has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Complex crystallizes in orthorhombic sp. gr. Pmn2{sub 1} with Z = 4. The Cd{sub 2} unit doublebridged by one carboxylate oxygen atom and two neighboring nitrogen atoms from the tda{sup 3–} ligands are linked by the tda{sup 3–}ligands to lead to the 2D (4,4) network in the ac plane. The almost coplanar Cd{sub 2}(μ{sub 5}-tda){sub 2} unit comprised of two Cd ions double-bridged by two tda{sup 3–} ligands through the neighboring nitrogen atoms is connected with the other four Cd{sub 2}(μ{sub 5}-tda){sub 2} units form the undulating 2D network in the ac plane. The (4,4) networks and undulating 2D networks are alternatively connected along the b axis by the tda{sup 3–} ligands coordinating to the Cd ions to form the 3D framework.

FT-Raman and FT-IR studies of 1:2.5 piroxicam: β-cyclodextrin inclusion compound

Science.gov (United States)

Bertoluzza, A.; Rossi, M.; Taddei, P.; Redenti, E.; Zanol, M.; Ventura, P.

1999-05-01

The FT-Raman and FT-IR spectra of amorphous 1:2.5 piroxicam (P): β-cyclodextrin (βCD) inclusion compound (PβCD) are presented and discussed in comparison with the spectra of the three main modifications of piroxicam (α,β and monohydrate). In the 1700-1200 cm -1 FT-Raman spectrum of 1:2.5 PβCD inclusion compound the bands of βCD are weak and covered by those stronger of piroxicam, differently from the FT-IR spectrum where the bands of βCD are stronger, so covering a large part of the spectrum. Typical FT-Raman marker bands are assigned for the characterization of the three modifications of piroxicam. The FT-Raman spectrum of 1:2.5 PβCD inclusion compound predominantly shows the bands at about 1465 and 1400 cm -1 of the monohydrate, indicating that piroxicam assumes the zwitterionic structure stabilized by interaction with βCD via electrostatic and hydrogen bonds. The dipolar character of 1:2.5 PβCD inclusion compound improves the solubility and the dissolution rate of piroxicam and thus its rate of absorption.

Luminescent properties of Eu2+ and Ce3+ ions in strontium litho-silicate Li2SrSiO4

International Nuclear Information System (INIS)

Dotsenko, V.P.; Levshov, S.M.; Berezovskaya, I.V.; Stryganyuk, G.B.; Voloshinovskii, A.S.; Efryushina, N.P.

2011-01-01

The luminescent properties of Eu 2+ and Ce 3+ ions in Li 2 SrSiO 4 have been studied upon excitation in the 2-20 eV region. Based on the results of luminescent measurements, values of the crystal field splitting and the centroid shift of the Ce 3+ 5d configuration in Li 2 SrSiO 4 were found and compared with those of Ce 3+ ions in some other inorganic compounds. The Eu 2+ ions in Li 2 SrSiO 4 exhibit a broad band emission with a maximum at 576 nm, which is due to the 4f 6 5d→4f 7 transition. It was shown that the long-wavelength position of the Eu 2+ emission in Li 2 SrSiO 4 is caused by the large crystal-field splitting of the Eu 2+ 4f 6 5d configuration and relatively high degree of covalency of the Eu-O bond. The stabilization of Eu 2+ ions in Li 2 SrSiO 4 during the synthesis process requires a strong reducing agent. Two phenomenological approaches to explain the low stability of Eu 2+ in Li 2 SrSiO 4 are also discussed.

Densification, characterization and oxidation studies of novel TiB{sub 2}+EuB{sub 6} compounds

Energy Technology Data Exchange (ETDEWEB)

Murthy, T.S.R.Ch., E-mail: murthi@barc.gov.in [Materials Group, Bhabha Atomic Research Centre, Mumbai (India); Sonber, J.K.; Vishwanadh, B. [Materials Group, Bhabha Atomic Research Centre, Mumbai (India); Nagaraj, A. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai (India); Sairam, K.; Bedse, R.D.; Chakravartty, J.K. [Materials Group, Bhabha Atomic Research Centre, Mumbai (India)

2016-06-15

TiB{sub 2}+EuB{sub 6} ceramic samples with different EuB{sub 6} contents were fabricated using hot -pressing technique. The introduction of EuB{sub 6} promoted the sinterability, fracture toughness and oxidation resistance of TiB{sub 2}. 98.7% TD achieved by adding 2.5% EuB{sub 6} to TiB{sub 2} by hot pressing at a relatively low temperature of 1750 °C, 35 MPa, 1h. Formation of complete solid solution of TiB{sub 2}+EuB{sub 6} observed for all the samples by XRD, EDS and EBSD. Hardness of all samples is measured in the range of 24–27 GPa ∼50% higher fracture toughness value of 5.2 MPa m{sup 1/2} was obtained in the 2.5% EuB{sub 6} contained sample compared to monolithic TiB{sub 2}. Enhancement of oxidation resistance of TiB{sub 2} was observed by EuB{sub 6} addition due to the formation of EuBO{sub 3} and Eu{sub 2}O{sub 3}. Oxidized cross section of TiB{sub 2}+EuB{sub 6} sample was measured as 340 μm, which is ∼35% less than that of monolithic TiB{sub 2} (520 μm), after oxidation at 1400 °C for 8h. - Highlights: • 98.7% TD achieved by adding 2.5% EuB{sub 6} to TiB{sub 2}. • Formation of complete solid solution of TiB{sub 2}+EuB{sub 6} observed. • Fracture toughness value of 5.2 MPa m{sup 1/2} was obtained in the TiB{sub 2}+2.5% EuB{sub 6}. • EuBO{sub 3} and Eu{sub 2}O{sub 3} are enhanced the oxidation resistance of TiB{sub 2} + EuB{sub 6} compound. • Oxide layer thicknesses of TiB{sub 2} and TiB{sub 2}+EuB{sub 6} are 520 μm and 340 μm respectively.

Oral administration of the 5-HT6 receptor antagonists SB-357134 and SB-399885 improves memory formation in an autoshaping learning task.

Science.gov (United States)

Perez-García, Georgina; Meneses, Alfredo

2005-07-01

In this work we aimed to re-examine the 5-HT6 receptor role, by testing the selective antagonists SB-357134 (1-30 mg/kg p.o.) and SB-399885 (1-30 mg/kg p.o.) during memory consolidation of conditioned responses (CR%), in an autoshaping Pavlovian/instrumental learning task. Bioavailability, half-life and minimum effective dose to induce inappetence for SB-357134 were 65%, 3.4 h, and 30 mg/kg p.o., and for SB-399885 were 52%, 2.2 h, and 50 mg/kg p.o., respectively. Oral acute and chronic administration of either SB-357134 or SB-399885 improved memory consolidation compared to control groups. Acute administration of SB-357134, at 1, 3, 10 and 30 mg/kg, produced a CR% inverted-U curve, eliciting the latter dose a 7-fold increase relative to saline group. Acute injection of SB-399885 produced significant CR% increments, being 1 mg/kg the most effective dose. Repeated administration (7 days) of either SB-357134 (10 mg/kg) or SB-399885 (1 mg/kg) elicited the most significant CR% increments. Moreover, modeling the potential therapeutic benefits of 5-HT6 receptor blockade, acute or repeated administration of SB-399885, at 10 mg/kg reversed memory deficits produced by scopolamine or dizocilpine, and SB-357134 (3 and 10 mg/kg) prevented amnesia and even improved performance. These data support the notion that endogenously 5-HT acting, via 5-HT6 receptor, improves memory consolidation.

Rietveld refinement of the crystal structures of Rb2XSi5O12 (X = Ni, Mn

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Anthony M. T. Bell

2016-02-01

Full Text Available The synthetic leucite silicate framework mineral analogues Rb2XSi5O12 {X = Ni [dirubidium nickel(II pentasilicate] and Mn [dirubidium manganese(II pentasilicate]} have been prepared by high-temperature solid-state synthesis. The results of Rietveld refinements, using X-ray powder diffraction data collected using Cu Kα X-rays, show that the title compounds crystallize in the space group Pbca and adopt the cation-ordered structure of Cs2CdSi5O12 and other leucites. The structures consist of tetrahedral SiO4 and XO4 units sharing corners to form a partially substituted silicate framework. Extraframework Rb+ cations sit in channels in the framework. All atoms occupy the 8c general position for this space group. In these refined structures, silicon and X atoms are ordered onto separate tetrahedrally coordinated sites (T-sites. However, the Ni displacement parameter and the Ni—O bond lengths suggest that for the X = Ni sample, there may actually be some T-site cation disorder.

Synthesis and characteristics of a novel 3-D organic amine oxalate: (enH2)1.5[Bi3(C2O4)6(CO2CONHCH2CH2NH3)].6.5H2O

International Nuclear Information System (INIS)

Yu Xiaohong; Zhang Hanhui; Cao Yanning; Chen Yiping; Wang Zhen

2006-01-01

A novel 3-D compound of (enH 2 ) 1.5 [Bi 3 (C 2 O 4 ) 6 (CO 2 CONHCH 2 CH 2 NH 3 )].6.5H 2 O has been hydrothermally synthesized and characterized by IR, ultraviolet-visible diffuse reflection integral spectrum (UV-Vis DRIS), fluorescence spectra, TGA and single crystal X-ray diffraction. It crystallizes in the monoclinic system, space group C2/c with a=31.110(8)A, b=11.544(3)A, c=22.583(6)A, β=112.419(3) o , V=7497(3)A 3 , Z=8, R 1 =0.0463 and wR 2 =0.1393 for unique 7686 reflections I>2σ(I). In the title compound, the Bi atoms have eight-fold and nine-fold coordination with respect to the oxygen atoms, with the Bi atoms in distorted dodecahedron and monocapped square antiprism, respectively. The 3-D framework of the title compound contains channels and is composed of linkages between Bi atoms and oxalate units, forming honeycomb-like layers with two kinds of 6+6 membered aperture, and pillared by oxalate ligands and monamide groups. The channels have N-ethylamine oxalate monamide group - CO 2 CONHCH 2 CH 2 NH 3 + , which is formed by the in situ reaction of en and oxalate acid. At room temperature, the complex exhibits intense blue luminescence with an emission peak at 445nm

Hydrothermal synthesis of 4ZnO·B2O3·H2O:Ln3 + (Ln = Eu, Tb) phosphors: Morphology-tunable and luminescence properties

Science.gov (United States)

Cao, Shiwei; Jiao, Yang; Han, Weifang; Ge, Chunhua; Song, Bo; Wang, Jie; Zhang, Xiangdong

2018-02-01

4ZnO·B2O3·H2O:Ln3 + (Ln = Eu, Tb) phosphors with different morphologies have been successfully synthesized via one-step hydrothermal method through regulating the molar amount of Eu3 + and Tb3 +. Comprehensive scanning electron microscopy (SEM), X-ray diffraction (XRD) Fourier transform infrared spectrum (FT-IR) and inductively coupled plasma atomic emission spectrometer (ICP-AES) characterizations all confirm that obtained products are 4ZnO·B2O3·H2O:Ln3 + (Ln = Eu, Tb). The experimental results displayed that the morphology and photoluminescence of compounds is regularly changed with increased the molar amount of rare earth ions. For the Eu3 +-doped, Tb3 +-doped and Eu3 +/Tb3 + co-doped 4ZnO·B2O3·H2O phosphors of morphologies, the rod-like structures gradually changed to flower-like structures, fine wire-like structure and hybrid structure, respectively. To their photoluminescence, the Eu3 + shows a red emission (615 nm); the Tb3 + shows a green emission (545 nm); for the Eu3 +/Tb3 + co-doped 4ZnO·B2O3·H2O phosphors, a combination of blue (5d-4f of Eu2 +), green (5D4-7F5 of Tb3 +) and red (5D0-7F2 of Eu3 +) emissions emerges to achieve white emission. In addition, the energy transfer among Eu3 +, Eu2 + and Tb3 + ions was also discussed.

Electrical and Thermal Conductivity and Conduction Mechanism of Ge2Sb2Te5 Alloy

Science.gov (United States)

Lan, Rui; Endo, Rie; Kuwahara, Masashi; Kobayashi, Yoshinao; Susa, Masahiro

2018-06-01

Ge2Sb2Te5 alloy has drawn much attention due to its application in phase-change random-access memory and potential as a thermoelectric material. Electrical and thermal conductivity are important material properties in both applications. The aim of this work is to investigate the temperature dependence of the electrical and thermal conductivity of Ge2Sb2Te5 alloy and discuss the thermal conduction mechanism. The electrical resistivity and thermal conductivity of Ge2Sb2Te5 alloy were measured from room temperature to 823 K by four-terminal and hot-strip method, respectively. With increasing temperature, the electrical resistivity increased while the thermal conductivity first decreased up to about 600 K then increased. The electronic component of the thermal conductivity was calculated from the Wiedemann-Franz law using the resistivity results. At room temperature, Ge2Sb2Te5 alloy has large electronic thermal conductivity and low lattice thermal conductivity. Bipolar diffusion contributes more to the thermal conductivity with increasing temperature. The special crystallographic structure of Ge2Sb2Te5 alloy accounts for the thermal conduction mechanism.

Electrical and Thermal Conductivity and Conduction Mechanism of Ge2Sb2Te5 Alloy

Science.gov (United States)

Lan, Rui; Endo, Rie; Kuwahara, Masashi; Kobayashi, Yoshinao; Susa, Masahiro

2017-11-01

Ge2Sb2Te5 alloy has drawn much attention due to its application in phase-change random-access memory and potential as a thermoelectric material. Electrical and thermal conductivity are important material properties in both applications. The aim of this work is to investigate the temperature dependence of the electrical and thermal conductivity of Ge2Sb2Te5 alloy and discuss the thermal conduction mechanism. The electrical resistivity and thermal conductivity of Ge2Sb2Te5 alloy were measured from room temperature to 823 K by four-terminal and hot-strip method, respectively. With increasing temperature, the electrical resistivity increased while the thermal conductivity first decreased up to about 600 K then increased. The electronic component of the thermal conductivity was calculated from the Wiedemann-Franz law using the resistivity results. At room temperature, Ge2Sb2Te5 alloy has large electronic thermal conductivity and low lattice thermal conductivity. Bipolar diffusion contributes more to the thermal conductivity with increasing temperature. The special crystallographic structure of Ge2Sb2Te5 alloy accounts for the thermal conduction mechanism.

Preparation and crystal structure of Ca4Sb2O

International Nuclear Information System (INIS)

Eisenmann, B.; Limartha, H.; Schaefer, H.

1980-01-01

The formerly described compound Ca 2 Sb is to be corrected to Ca 4 Sb 2 O as shown by X-ray diffractometer data of single crystals and neutron diffraction diagrams of powders. The compound crystallizes in the K 2 NiF 4 structure type. (orig.)

Molecular dynamics simulation based on the multi-component molecular orbital method: Application to H5O2+,D5O2+,andT5O2+

International Nuclear Information System (INIS)

Ishimoto, Takayoshi; Koyama, Michihisa

2012-01-01

Graphical abstract: Molecular dynamics method based on multi-component molecular orbital method was applied to basic hydrogen bonding systems, H 5 O 2 + , and its isotopomers (D 5 O 2 + andT 5 O 2 + ). Highlights: ► Molecular dynamics method with nuclear quantum effect was developed. ► Multi-component molecular orbital method was used as ab initio MO calculation. ► Developed method applied to basic hydrogen bonding system, H 5 O 2 + , and isotopomers. ► O ⋯ O vibrational stretching reflected to the distribution of protonic wavefunctions. ► H/D/T isotope effect was also analyzed. - Abstract: We propose a molecular dynamics (MD) method based on the multi-component molecular orbital (MC M O) method, which takes into account the quantum effect of proton directly, for the detailed analyses of proton transfer in hydrogen bonding system. The MC M O based MD (MC M O-MD) method is applied to the basic structures, H 5 O 2 + (called “Zundel ion”), and its isotopomers (D 5 O 2 + andT 5 O 2 + ). We clearly demonstrate the geometrical difference of hydrogen bonded O ⋯ O distance induced by H/D/T isotope effect because the O ⋯ O in H-compound was longer than that in D- or T-compound. We also find the strong relation between stretching vibration of O ⋯ O and the distribution of hydrogen bonded protonic wavefunction because the protonic wavefunction tends to delocalize when the O ⋯ O distance becomes short during the dynamics. Our proposed MC M O-MD simulation is expected as a powerful tool to analyze the proton dynamics in hydrogen bonding systems.

Technology and optical characterization of luminophore coordination compounds Eu(o-MBA)3Phen and NC PEPC/Eu(o-MBA)3Phen

Science.gov (United States)

Bordian, Olga; Verlan, Victor; Culeac, Ion; Iovu, Mihail; Zubareva, Vera

2016-12-01

Were obtained a new nanocomposite (NC) based on poly N-epoxy prolyl carbazol (PEPC) and the coordination compound luminophore Eu(o-MBA)3Phen, where o-MBA is o- methylbenzoic acid and Phen - phenanthroline. Nanocrystals of Eu(o-MBA)3Phen with the dimensions 50 nm were uniformly incorporated into the PEPC polymer matrix with various concentrations. The absorption spectra of coordination compounds and thin layers of NC PEPC/Eu(o-MBA)3Phen revealed 1 intensive absorption bands at 2.02 eV. Photoluminescence (PL) spectra showed an intense red luminescence at 578 - 699 nm, which is assigned to the transitions 4D0->7Fi (i= 0,1,2 3 4) in the 4f-shell of the Eu3+ ion.

Crystal structure, vibrational spectra, optical and DFT studies of bis (3-azaniumylpropyl) azanium pentachloroantimonate (III) chloride monohydrate (C6H20N3)SbCl5·Cl·H2O

Science.gov (United States)

Ahmed, Houssem Eddine; Kamoun, Slaheddine

2017-09-01

The crystal structure of (C6H20N3)SbCl5·Cl·H2O is built up of [NH3(CH2)3NH2(CH2)3NH3]3 + cations, [SbCl5]2 - anions, free Cl- anions and neutral water molecules connected together by Nsbnd H ⋯ Cl, Nsbnd H ⋯ O and Osbnd H ⋯ Cl hydrogen bonds. The optical band gap determined by diffuse reflection spectroscopy (DRS) is 3.78 eV for a direct allowed transition. Optimized molecular geometry, atomic Mulliken charges, harmonic vibrational frequencies, HOMO-LUMO and related molecular properties of the (C6H20N3)SbCl5·Cl·H2O compound were calculated by Density functional theory (DFT) using B3LYP method with GenECP sets. The calculated structural parameters (bond lengths and angles) are in good agreement with the experimental XRD data. The vibrational unscaled wavenumbers were calculated and scaled by a proper scaling factor of 0.984. Acceptable consistency was observed between calculated and experimental results. The assignments of wavenumbers were made on the basis of potential energy distribution (PED) using Vibrational Energy Distribution Analysis (VEDA) software. The HOMO-LUMO study was extended to calculate various molecular parameters like ionization potential, electron affinity, global hardness, electro-chemical potential, electronegativity and global electrophilicity of the given molecule.

CdSe/beta-Pb0.33V2O5 heterostructures: Nanoscale semiconductor interfaces with tunable energetic configurations for solar energy conversion and storage

Science.gov (United States)

Milleville, Christopher C.

This dissertation focuses on the formation and characterization of semiconductor heterostructures, consisting of light-harvesting cadmium selenide quantum dots (CdSe QDs) and single crystalline lead vanadium oxide nanowires (β-Pb0.33V2O5 NWs), for the purpose of excited-state charge transfer and photocatalytic production of solar fuels. We reported two distinct routes for assembling CdSe/β-Pb0.33V2O5 heterostructures: linker-assisted assembly (LAA) mediated by a bifunctional ligand and successive ionic layer adsorption and reaction (SILAR). In the former case, the thiol end of a molecular linker, cysteine (Cys) is found to bind to the QD surface, whereas a protonated amine moiety interacts electrostatically with the negatively charged NW surface. In the alternative SILAR route, the surface coverage of CdSe on the β-Pb0.33V2O5 NWs is tuned by varying the number of successive precipitation cycles. Hard X-ray photoelectron spectroscopy (HAXPES) measurements revealed that the mid-gap states of β-Pb0.33V2O5 NWs are closely overlapped in energy with the valence band edges of CdSe QDs, suggesting that hole transfer from the valence band of CdSe into the mid-gap states is possible. Preliminary evidence of hole transfer was obtained through photoluminescence quenching experiments. Steady-state and time-resolved photoluminescence measurements on Cys-CdSe dispersions, mixed dispersions of Cys-CdSe QDs and β-Pb0.33V¬2O5 NWs, and mixed dispersions of Cys-CdS QDs and V2O5 revealed a greater extent of quenching of the emission of Cys-CdSe QDs by β Pb0.33V¬2O5 relative to V2O5. V2O5, devoid of mid-gap states, is unable to accept holes from CdSe and therefore should not quench emission to the same extent as β-Pb0.33V¬2O5. The additional quenching was dynamic, consistent with a mechanism involving the transfer of photogenerated holes from CdSe QDs to the mid-gap states of β Pb0.33V2O5. Transient absorption spectroscopy (TA) was used to probe the dynamics of interfacial

Ferromagnetic half-metallic characteristic in bulk Ni 0.5M 0.5O (M=Cu, Zn and Cd): A GGAU study

KAUST Repository

Mi, Wenbo; Yang, Hua; Cheng, Yingchun; Bai, Haili

2012-01-01

Ferromagnetic half metallicity with a high spin polarization of 100% was predicted in the bulk Ni 0.5Cu 0.5O using density-functional theory method. The band gap of majority spin is 3.45 eV for Ni 0.5Cu 0.5O. The density of states of minority spin at the Fermi level are mainly from Cu 3d and O 2p in the Ni 0.5Cu 0.5O. The magnetic moments are from Ni 3d states. Ni 0.5Zn 0.5O and Ni 0.5Cd 0.5O systems are ferromagnetic insulators, but the magnetic moment of Ni 2 ions is enhanced by the Zn and Cd incorporation. Therefore, Ni 0.5Cu 0.5O is the potential candidate for spintronics devices because of the predicted high spin polarization. © 2012 Elsevier Ltd. All rights reserved.

Ferromagnetic half-metallic characteristic in bulk Ni 0.5M 0.5O (M=Cu, Zn and Cd): A GGAU study

KAUST Repository

Mi, Wenbo

2012-07-01

Ferromagnetic half metallicity with a high spin polarization of 100% was predicted in the bulk Ni 0.5Cu 0.5O using density-functional theory method. The band gap of majority spin is 3.45 eV for Ni 0.5Cu 0.5O. The density of states of minority spin at the Fermi level are mainly from Cu 3d and O 2p in the Ni 0.5Cu 0.5O. The magnetic moments are from Ni 3d states. Ni 0.5Zn 0.5O and Ni 0.5Cd 0.5O systems are ferromagnetic insulators, but the magnetic moment of Ni 2 ions is enhanced by the Zn and Cd incorporation. Therefore, Ni 0.5Cu 0.5O is the potential candidate for spintronics devices because of the predicted high spin polarization. © 2012 Elsevier Ltd. All rights reserved.

Microstructure, mechanical properties, and thermoelectric properties of hot-extruded p-type Te-doped Bi{sub 0.5}Sb{sub 1.5}Te{sub 3} compounds

Energy Technology Data Exchange (ETDEWEB)

Park, K; Seo, J; Lee, C

1997-07-01

The p-type Bi{sub 0.5}Sb{sub 1.5}Te{sub 3} compounds with Te dopant (4.0 and 6.0 wt%) and without dopant were fabricated by hot extrusion in the temperature range of 300 to 510 C under an extrusion ratio of 20:1. The undoped and Te doped compounds were highly dense and showed high crystalline quality. The grains contained many dislocations and were fine equiaxed ({approximately}1.0 {micro}m) owing to the dynamic recrystallization during the extrusion. The hot extrusion gave rise to the preferred orientation of grains. The bending strength and the figure of merit of the undoped and Te doped compounds were increased with increasing the extrusion temperature. The Te dopant significantly increased the figure of merit. The values of the figure of merit of the undoped and 4.0 wt% Te-doped compounds hot extruded at 440 C were 2.11 x 10{sup {minus}3}/K and 2.94 x 10{sup {minus}3}/K, respectively.

Theoretical and experimental investigations of the properties of Ge2Sb2Te5 and indium-doped Ge2Sb2Te5 phase change material

Science.gov (United States)

Singh, Gurinder; Kaura, Aman; Mukul, Monika; Singh, Janpreet; Tripathi, S. K.

2014-06-01

We have carried out comprehensive computational and experimental study on the face-centered cubic Ge2Sb2Te5 (GST) and indium (In)-doped GST phase change materials. Structural calculations, total density of states and crystal orbital Hamilton population have been calculated using first-principle calculation. 5 at.% doping of In weakens the Ge-Te, Sb-Te and Te-Te bond lengths. In element substitutes Sb to form In-Te-like structure in the GST system. In-Te has a weaker bond strength compared with the Sb-Te bond. However, both GST and doped alloy remain in rock salt structure. It is more favorable to replace Sb with In than with any other atomic position. X-ray diffraction (XRD) analysis has been carried out on thin film of In-doped GST phase change materials. XRD graph reveals that In-doped phase change materials have rock salt structure with the formation of In2Te3 crystallites in the material. Temperature dependence of impedance spectra has been calculated for thin films of GST and doped material. Thickness of the as-deposited films is calculated from Swanepoel method. Absorption coefficient (α) has been calculated for amorphous and crystalline thin films of the alloys. The optical gap (indirect band gap) energy of the amorphous and crystalline thin films has also been calculated by the equation α hν = β (hν - E_{{g }} )2 . Optical contrast (C) of pure and doped phase change materials have also been calculated. Sufficient optical contrast has been found for pure and doped phase change materials.

Theoretical and experimental investigations of the properties of Ge2Sb2Te5 and indium-doped Ge2Sb2Te5 phase change material

International Nuclear Information System (INIS)

Singh, Gurinder; Kaura, Aman; Mukul, Monika; Singh, Janpreet; Tripathi, S.K.

2014-01-01

We have carried out comprehensive computational and experimental study on the face-centered cubic Ge 2 Sb 2 Te 5 (GST) and indium (In)-doped GST phase change materials. Structural calculations, total density of states and crystal orbital Hamilton population have been calculated using first-principle calculation. 5 at.% doping of In weakens the Ge-Te, Sb-Te and Te-Te bond lengths. In element substitutes Sb to form In-Te-like structure in the GST system. In-Te has a weaker bond strength compared with the Sb-Te bond. However, both GST and doped alloy remain in rock salt structure. It is more favorable to replace Sb with In than with any other atomic position. X-ray diffraction (XRD) analysis has been carried out on thin film of In-doped GST phase change materials. XRD graph reveals that In-doped phase change materials have rock salt structure with the formation of In 2 Te 3 crystallites in the material. Temperature dependence of impedance spectra has been calculated for thin films of GST and doped material. Thickness of the as-deposited films is calculated from Swanepoel method. Absorption coefficient (α) has been calculated for amorphous and crystalline thin films of the alloys. The optical gap (indirect band gap) energy of the amorphous and crystalline thin films has also been calculated by the equation αhν = β(hν - E g ) 2 . Optical contrast (C) of pure and doped phase change materials have also been calculated. Sufficient optical contrast has been found for pure and doped phase change materials. (orig.)

Stability Criteria of Fullerene-like Nanoparticles: Comparing V2O5 to Layered Metal Dichalcogenides and Dihalides

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Yehiam Prior

2010-08-01

Full Text Available Numerous examples of closed-cage nanostructures, such as nested fullerene-like nanoparticles and nanotubes, formed by the folding of materials with layered structure are known. These compounds include WS2, NiCl2, CdCl2, Cs2O, and recently V2O5. Layered materials, whose chemical bonds are highly ionic in character, possess relatively stiff layers, which cannot be evenly folded. Thus, stress-relief generally results in faceted nanostructures seamed by edge-defects. V2O5, is a metal oxide compound with a layered structure. The study of the seams in nearly perfect inorganic "fullerene-like" hollow V2O5 nanoparticles (NIF-V2O5 synthesized by pulsed laser ablation (PLA, is discussed in the present work. The relation between the formation mechanism and the seams between facets is examined. The formation mechanism of the NIF-V2O5 is discussed in comparison to fullerene-like structures of other layered materials, like IF structures of MoS2, CdCl2, and Cs2O. The criteria for the perfect seaming of such hollow closed structures are highlighted.

In Vivo Immunotoxicity of SiO2@(Y0.5Gd0.45Eu0.052O3 as Dual-Modality Nanoprobes

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Xiumei Tian

2014-08-01

Full Text Available We have successfully synthesized SiO2@(Y0.5Gd0.45Eu0.052O3 nanocomposites as a potential dual-modality nanoprobe for molecular imaging in vitro. However, their immunotoxicity assessment in vivo remains unknown. In this article, the in vitro biocompatibility of our dual-modality nanoprobes was assayed in terms of cell viability and apoptosis. In vivo immunotoxicity was investigated by monitoring the generation of reactive oxygen species (ROS, cluster of differentiation (CD markers and cytokines in Balb/c mice. The data show that the in vitro biocompatibility was satisfactory. In addition, the immunotoxicity data revealed there are no significant changes in the expression levels of CD11b and CD71 between the nanoprobe group and the Gd in a diethylenetriaminepentaacetic acid (DTPA chelator (Gd-DTPA group 24 h after injection in Balb/c mice (p > 0.05. Importantly, there are significant differences in the expression levels of CD206 and CD25 as well as the secretion of IL-4 and the generation of ROS 24 h after injection (p < 0.05. Transmission electron microscopy (TEM images showed that few nanoprobes were localized in the phagosomes of liver and lung. In conclusion, the toxic effects of our nanoprobes may mainly result from the aggregation of particles in phagosomes. This accumulation may damage the microstructure of the cells and generate oxidative stress reactions that further stimulate the immune response. Therefore, it is important to evaluate the in vivo immunotoxicity of these rare earth-based biomaterials at the molecular level before molecular imaging in vivo.

3-Hydroxy-2-[(4-hydroxy-3,5-dimethoxyphenyl(2-hydroxy-4,4-dimethyl-6-oxocyclohex-1-en-1-ylmethyl]-5,5-dimethylcyclohex-2-en-1-one

Directory of Open Access Journals (Sweden)

Xiao-Hui Yang

2011-02-01

Full Text Available In the title compound, C25H32O7, the 3-hydroxy-5,5-dimethylcyclohex-2-enone rings adopt slightly distorted envelope conformations with the two planes at the base of the envelope forming dihedral angles of 57.6 (4 and 53.9 (9° with the benzene ring. There is an intramolecular hydroxy–ketone O—H...O interaction between the two substituted cyclohexane rings as well as a short intramolecular phenol–methoxy O—H...O interaction.

Hydrothermal synthesis, characterization, and luminescence of Ca{sub 2}B{sub 2}O{sub 5}:RE (RE = Eu{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) nanofibers

Energy Technology Data Exchange (ETDEWEB)

Yang, Li; Wan, Yingpeng; Li, Yuze; Pu, Yinfu; Huang, Yanlin, E-mail: huang@suda.edu.cn [Soochow University, State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science (China); Chen, Cuili; Seo, Hyo Jin, E-mail: hjseo@pknu.ac.kr [Pukyong National University, Department of Physics and Interdisciplinary Program of Biomedical Engineering (Korea, Republic of)

2016-04-15

Ca{sub 2}B{sub 2}O{sub 5}:RE (RE = Eu{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) nanofibers were synthesized by the hydrothermal reaction method. The structural refinement was conducted on the base of the X-ray powder diffraction (XRD) measurements. The surface properties of the Ca{sub 2}B{sub 2}O{sub 5}:RE (RE = Eu{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) nanofibers were investigated by the measurements such as the scanning electron microscope (SEM), transmission electron microscope (TEM), and the energy dispersive spectrum (EDS). The nanofiber has a diameter of about 100 nm and a length of several micrometers. The luminescence properties such as photoluminescence excitation (PLE) and emission spectra (PL), decay lifetime, color coordinates, and the absolute internal quantum efficiency (QE) were reported. Ca{sub 2}B{sub 2}O{sub 5}:Eu{sup 3+} nanofibers show the red luminescence with CIE coordinates of (x = 0.41, y = 0.51) and the luminescence lifetime of 0.63 ms. The luminescence of Ca{sub 2}B{sub 2}O{sub 5}:Tb{sup 3+} nanofibers is green color (x = 0.29, y = 0.53) with the lifetime of 2.13 ms. However, Dy{sup 3+}-doped Ca{sub 2}B{sub 2}O{sub 5} nanofibers present a single-phase white-color phosphor with the fluorescence decay of 3.05 ms. Upon near-UV excitation, the absolute quantum efficiency is measured to be 65, 35, and 37 % for Eu{sup 3+}-, Tb{sup 3+}-, Dy{sup 3+}-doped Ca{sub 2}B{sub 2}O{sub 5} nanofibers, respectively. It is suggested that Ca{sub 2}B{sub 2}O{sub 5}:RE (RE = Eu{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) nanofibers could be an efficient phosphor for lighting and display.

Lattice mismatch and energy transfer of Eu- and Dy-codoped MO–Al{sub 2}O{sub 3}–SrO (M=Mg, Ca, Ba) ternary compounds affecting luminescence behavior

Energy Technology Data Exchange (ETDEWEB)

Liang, Chen-Jui, E-mail: cjliang@fcu.edu.tw; Huang, Kuan-Yu

2017-05-15

A systematic investigation of energy transfers and luminescence behaviors for M{sub x}Sr{sub 0.94−x}Al{sub 2}O{sub 4}:Eu{sub 0.02}, Dy{sub 0.04} (M=Mg, Ca, Ba; x=0, 0.235, 0.47, 0.705, 0.94) ternary compounds was accomplished. The results demonstrated that six phenomena must be fitted into the energy-transfer mechanisms of the ternary compounds: (1) the optical band-gap energy of Mg{sub 0.94}Al{sub 2}O{sub 4}:Eu{sub 0.02}Dy{sub 0.04} is extremely low and does not allow photoemission; (2) Ca{sup 2+} and Ba{sup 2+} ions are the main hosts when x≥0.47 in Ca{sub x}Sr{sub 1−x}Al{sub 2}O{sub 4}:Eu{sub 0.02}Dy{sub 0.04} and Ba{sub x}Sr{sub 1−x}Al{sub 2}O{sub 4}:Eu{sub 0.02}Dy{sub 0.04}, respectively; (3) Eu{sup 3+} ions are the main activator ions in Ca{sub x}Sr{sub 1−x}Al{sub 2}O{sub 4}:Eu{sub 0.02}Dy{sub 0.04} with x=0.47 and in Ba{sub x}Sr{sub 1−x}Al{sub 2}O{sub 4}:Eu{sub 0.02}Dy{sub 0.04} with x=0.353−0.705; (4) Sr{sup 2+} and Eu{sup 2+} ions are the main host and activator ions, respectively, when x<0.353 in each ternary compound; (5) energy transfers from the MO phases to the SrO phase because the conduction band energy of SrO is the lowest; and (6) mutual substitution between alkaline-earth ions does not alter the resultant structures’ crystal field and nephelauxetic effects, as determined by measuring their luminescence. Two energy transfer paths were discovered to be possible in CaO–Al{sub 2}O{sub 3}–SrO and BaO–Al{sub 2}O{sub 3}–SrO ternary compounds, and the boundaries determining which path was chosen were the atomic ratios Ca:Sr and Ba:Sr, both approximately 1.6:1 (x=0.353). Because second path increased the energy transferred from the MO band gap to the SrO band gap, the corresponding structure's spectrum emission intensity was approximately 4.3 times higher than that of the SrO−Al{sub 2}O{sub 3} binary compound, and their photoluminescence was thus substantially higher.

Comparative Study of Catalytic Oxidation of Ethanol to Acetaldehyde Using Fe(III Dispersed on Sb2O5 Grafted on SiO2 and on Untreated SiO2 Surfaces

Directory of Open Access Journals (Sweden)

Benvenutti Edilson V.

1998-01-01

Full Text Available Fe(III was supported on Sb(V oxide grafted on the silica gel surface and directly on the silica gel surface using ion-exchange and impregnation processes producing Fe/Sb/SiO2 and Fe/SiO2, respectively. The catalytic conversion of ethanol to acetaldehyde was much more efficient using Fe/Sb/SiO2 than Fe/SiO2 as catalyst. This higher efficiency of the former catalyst takes into account two aspects: a the new phase FeSbO4 formed when Fe/Sb/SiO2 is heat treated and, b it is higher dispersion on the matrix.

2-Amino-5-bromopyridinium 2-hydroxybenzoate

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Ching Kheng Quah

2010-08-01

Full Text Available In the title compound, C5H6BrN2+·C7H5O3−, the 2-amino-5-bromopyridinium cation and 2-hydroxybenzoate anion are essentially planar with maximum deviations of 0.020 (1 and 0.018 (2 Å, respectively. The anion is stabilized by an intramolecular O—H...O hydrogen bond, which generates an S(6 ring motif. In the crystal, the cations and anions are linked by N—H...O hydrogen bonds into chains propagating along [010]. The chains contain R22(8 ring motifs. The structure is further stabilized by π–π stacking interactions [centroid–centroid distances = 3.4908 (10 and 3.5927 (10 Å] and also features short Br...O contacts [2.9671 (13 Å].

Intrinsic radioactivity of KSr2I5:Eu2+

International Nuclear Information System (INIS)

Rust, M.; Melcher, C.; Lukosi, E.

2016-01-01

A current need in nuclear security is an economical, yet high energy resolution (near 2%), scintillation detector suitable for gamma-ray spectroscopy. For current scintillators on the market, there is an inverse relationship between scintillator energy resolution and cost of production. A new promising scintillator, KSr 2 I 5 :Eu 2+ , under development at the University of Tennessee, has achieved an energy resolution of 2.4% at 662 keV at room temperature, with potential growth rates exceeding several millimeters per hour. However, the internal background due to the 40 K content could present a hurdle for effective source detection/identification in nuclear security applications. As a first step in addressing this question, this paper reports on a computational investigation of the intrinsic differential pulse height spectrum (DPHS) generated by 40 K within the KSr 2 I 5 :Eu 2+ scintillator as a function of crystal geometry. It was found that the DPHS remains relatively equal to a constant multiplicative factor of the negatron emission spectrum with a direct increase of the 1.46 MeV photopeak relative height to the negatron spectrum with volume. Further, peak pileup does not readily manifest itself for practical KSr 2 I 5 :Eu 2+ volumes.

2-Amino-5-bromopyridinium trifluoroacetate

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Madhukar Hemamalini

2010-04-01

Full Text Available In the title compound, C5H6BrN2+·C2F3O2−, the F atoms of the anion are disordered over two sets of sites, with occupancies of 0.59 (2:0.41 (2. In the crystal structure, the anions and cations are linked into a two-dimensional network parallel to (100 by N—H...O and C—H...O hydrogen bonds. Within this network, the N—H...O hydrogen bonds generate R22(8 ring motifs.

2-Hydroxy-5-nitrobenzaldehyde

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Şamil Işık

2009-12-01

Full Text Available The title compound, C7H5NO4, is essentially planar, with a maximum deviation from the mean plane of 0.0116 (11 Å for the hydroxy O atom. The molecular and crystal structure are stabilized by intra- and intermolecular interactions. An intramolecular O—H...O hydrogen bond generates a six-membered ring, producing an S(6 ring motif. The C—H...O interactions result in the formation of C(5 chains and R22(8 rings forming an approximately planar network parallel to (10overline{1}. These planes are interconnected through π–π interactions [centroid–centroid distance 3.582 (2 Å].

3+ and [Sb13Se16Br2] 5+ - Double and quadruple spiro cubanes from ionic liquids

KAUST Repository

Ahmed, Ejaz

2014-01-08

The reaction of antimony and selenium in the bromine-rich Lewis acidic ionic liquid [BMIm]Br·4.7AlBr3 (BMIm: 1-butyl-3- methylimidazolium) in the presence of a small amount of NbCl5 at 160 °C yielded dark-red crystals of [Sb7Se8Br 2][AlX4]3. For X = Cl0.15(1)Br 0.85(1), the compound is isostructural to [Sb7S 8Br2][AlCl4]3 [P212 121, a = 12.5132(5) Å, b = 17.7394(6) Å, c = 18.3013(6) Å]. For a higher chlorine content, X = Cl 0.58(1)Br0.42(1), a slightly disordered variant with a bisected unit cell is found [P21212, a = 12.3757(3) Å, b = 17.4116(5) Å, c = 9.0420(2) Å]. The [Sb 7Se8Br2]3+ heteropolycation (C 2 symmetry) is a spiro double-cubane with an antimony atom on the shared corner. From this distorted octahedrally coordinated central atom, tricoordinate selenium and antimony atoms alternate in the bonding sequence. The terminal antimony atoms each bind to a bromine atom. Quantum chemical calculations confirm polar covalent Sb-Se bonding within the cubes and indicate three-center, four-electron bonds for the six-coordinate spiro atoms. The calculated charge distribution reflects the electron-donor role of the antimony atoms. The use of a chlorine-rich ionic liquid resulted in the formation of triclinic [Sb13Se16Br2][AlX4] 5 with X = Cl0.80(1)Br0.20(1) [P$\\\\bar {1}$, a = 9.0842(5) Å, b = 19.607(1) Å, c = 21.511(1) Å, α = 64.116(6), β = 79.768(7), γ = 88.499(7)]. The cationic cluster [Sb13Se16Br2]5+ is a bromine-terminated spiro quadruple-cubane. This 31 atom concatenation of four cubes is assumed to be the largest known discrete main group polycation. A similar reaction in a chloride-free system yielded [Sb7Se 8Br2][Sb13Se16Br2] [AlBr4]8. In its monoclinic structure [P2/c, a = 27.214(5) Å, b = 9.383(2) Å, c = 22.917(4) Å, β = 101.68(1)], the two types of polycations alternate in layers along the a axis. In the series [Sb4+3nSe4+4nBr2](2+n)+, these cations are the members with n = 1 and 3. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGa

Optical properties of ZrO2, SiO2 and TiO2-SiO2 xerogels and coatings doped with Eu3+ and Eu2+

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Gonçalves Rogéria R.

1999-01-01

Full Text Available Eu3+ doped bulk monoliths and thin films were obtained by sol-gel methods in the ZrO2, SiO2 and SiO2-TiO2 systems. Eu3+ 5D0 ® 7FJ emission and decay time characteristics were measured during the entire experimental preparation route from the initial sol to the final xerogels. The crystalline phases identified were tetragonal ZrO2 and mixtures of rutile and anatase TiO2 at high temperature treatments in bulk samples. Good quality thin films were obtained for all systems by dip-coating optical glasses (Schott BK270. The same spectroscopic features were observed either for the bulk monoliths or the films. By appropriate heat treatments under H2 atmosphere Eu2+ containing samples could be obtained in the SiO2-TiO2 system.

Phase formation of V2O5.xNb2O5 compounds via gels and freeze-dried precursors

International Nuclear Information System (INIS)

Langbein, Hubert; Mayer-Uhma, Tobias

2009-01-01

An X-ray powder diffraction study of the phase formation in the system V 2 O 5 /Nb 2 O 5 is performed. Freeze-dried ammonium vanadate and ammonium oxalato niobate, alkoxide-derived xerogels and a mixture of active oxides are used as precursors to compare the resulting phase composition. Thermal decomposition of the freeze-dried precursor is monitored with DTA/TG and mass spectrometry. In the quasi-binary system V 2 O 5 -Nb 2 O 5 metastable VNbO 5 , V 4 Nb 18 O 55 , VNb 9 O 25 and solid solutions of V 2 O 5 in TT-Nb 2 O 5 as also thermodynamically stable VNb 9 O 25 exist. The thermal decomposition of freeze-dried vanadate-oxalatoniobate solution allows the synthesis of all these phases in a relative simple manner. Structural relationships between an intermediate phase and the product, or, in the case of solid-state reactions, between one of the starting oxide and the product, favour the desired reaction. Therefore, the structure of a former phase influences or directs the structure of the product similar to a topotactic reaction

Effects of dopants on the amorphous-to-fcc transition in Ge{sub 2}Sb{sub 2}Te{sub 5} thin films

Energy Technology Data Exchange (ETDEWEB)

Privitera, S. [R and D Department, Micro, Power, Analog (MPA) Group, STMicroelectronics, MP8, Stradale Primosole 50, 95121 Catania (Italy)]. E-mail: stefania.privitera@st.com; Rimini, E. [Istituto di Microelettronica e Microsistemi (IMM), Consiglio Nazionale delle Ricerche (CNR), Stradale Primosole 50, 95121 Catania (Italy); Bongiorno, C. [Istituto di Microelettronica e Microsistemi (IMM), Consiglio Nazionale delle Ricerche (CNR), Stradale Primosole 50, 95121 Catania (Italy); Pirovano, A. [FTM, Advanced R and D, NVMTD, STMicroelectronics, Via Olivetti 2, 20041, Agrate Brianza (Italy); Bez, R. [FTM, Advanced R and D, NVMTD, STMicroelectronics, Via Olivetti 2, 20041, Agrate Brianza (Italy)

2007-04-15

The amorphous-to-crystal transition has been studied through in situ resistance measurements in Ge{sub 2}Sb{sub 2}Te{sub 5} thin films doped by ion implantation with nitrogen, oxygen or fluorine at different concentrations. Enhancement of the thermal stability has been observed in O and N amorphous doped Ge{sub 2}Sb{sub 2}Te{sub 5}. Larger effects have been found in the case of nitrogen doping. On the contrary, doping with Fluorine produced a decrease in the crystallization temperature. The electrical properties have been related to the structural phase change through in situ transmission electron microscopy analysis. The comparison between undoped and doped Ge{sub 2}Sb{sub 2}Te{sub 5} shows that the introduction of oxygen or nitrogen modifies in a different way the kinetics of the amorphous-to-fcc transition and gives new insight on the effects of doping with light elements in GeSbTe alloys.

Phase relations and linear thermal expansion of cubic solid solutions in the Th1-xMxO2-x/2 (M=Eu, Gd, Dy) systems

International Nuclear Information System (INIS)

Mathews, M.D.; Ambekar, B.R.; Tyagi, A.K.

2005-01-01

Cell parameters and linear thermal expansion studies of the Th-M oxide systems with general compositions Th 1-x M x O 2-x/2 (M=Eu 3+ , Gd 3+ and Dy 3+ , 0.0= 1.5 in the ThO 2 lattice. The upper solid solubility limits of EuO 1.5 , GdO 1.5 and DyO 1.5 in the ThO 2 lattice under conditions of slow cooling from 1673K are represented as Th 0.50 Eu 0.50 O 1.75 , Th 0.60 Gd 0.40 O 1.80 and Th 0.85 Dy 0.15 O 1.925 , respectively. The linear thermal expansion (293-1123K) of MO 1.5 and their single-phase solid solutions with thoria were investigated by dilatometery. The average linear thermal expansion coefficients (α-bar ) of the compounds decrease on going from EuO 1.5 to DyO 1.5 . The values of α-bar for EuO 1.5 , GdO 1.5 and DyO 1.5 containing solid solutions showed a downward trend as a function of the dopant concentration. The linear thermal expansion (293-1473K) of the solid solutions investigated by high-temperature XRD also showed a similar trend

Two-magnon scattering in the 5d all-in-all-out pyrochlore magnet Cd2Os2O7.

Science.gov (United States)

Nguyen, Thi Minh Hien; Sandilands, Luke J; Sohn, C H; Kim, C H; Wysocki, Aleksander L; Yang, In-Sang; Moon, S J; Ko, Jae-Hyeon; Yamaura, J; Hiroi, Z; Noh, Tae Won

2017-08-15

5d pyrochlore oxides with all-in-all-out magnetic order are prime candidates for realizing strongly correlated, topological phases of matter. Despite significant effort, a full understanding of all-in-all-out magnetism remains elusive as the associated magnetic excitations have proven difficult to access with conventional techniques. Here we report a Raman spectroscopy study of spin dynamics in the all-in-all-out magnetic state of the 5d pyrochlore Cd 2 Os 2 O 7 . Through a comparison between the two-magnon scattering and spin-wave theory, we confirm the large single ion anisotropy in this material and show that the Dzyaloshinskii-Moriya and exchange interactions play a significant role in the spin-wave dispersions. The Raman data also reveal complex spin-charge-lattice coupling and indicate that the metal-insulator transition in Cd 2 Os 2 O 7 is Lifshitz-type. Our work establishes Raman scattering as a simple and powerful method for exploring the spin dynamics in 5d pyrochlore magnets.Pyrochlore 5d transition metal oxides are expected to have interesting forms of magnetic order but are hard to study with conventional probes. Here the authors show that Raman scattering can be used to measure magnetic excitations in Cd 2 Os 2 O 7 and that it exhibits complex spin-charge-lattice coupling.

Crystalline and Electronic Structures and Magnetic and Electrical Properties of La-Doped Ca2Fe2O5 Compounds

Science.gov (United States)

Phan, T. L.; Tho, P. T.; Tran, N.; Kim, D. H.; Lee, B. W.; Yang, D. S.; Thiet, D. V.; Cho, S. L.

2018-01-01

Brownmillerite Ca2Fe2O5 has been observed to exhibit many outstanding properties that are applicable to ecotechnology. However, very little work on doped Ca2Fe2O5 compounds has been carried out to widen their application scope. We present herein a detailed study of the crystalline/geometric and electronic structures and magnetic and electrical properties of Ca2- x La x Fe2O5 ( x = 0 to 1) prepared by conventional solid-state reaction. X-ray diffraction patterns indicated that the compounds with x = 0 to 0.05 exhibited brownmillerite-type single phase. La doping with higher content ( x ≥ 0.1) stimulated additive formation of Grenier- (LaCa2Fe3O8) and perovskite-type (LaFeO3) phases. Extended x-ray absorption fine structure spectroscopy at the Fe K-edge and electron spin resonance spectroscopy revealed presence of Fe3+ in the parent Ca2Fe2O5 ( x = 0) and both Fe3+ and Fe4+ in the doped compounds ( x ≥ 0.05). The Fe4+ content tended to increase with increasing x. This stimulates ferromagnetic exchange interactions between Fe3+ and Fe4+ ions and directly influences the magnetic properties of Ca2- x La x Fe2O5. Electrical resistivity ( ρ) measurements in the temperature range of T = 20 K to 400 K revealed that all the compounds exhibit insulator behavior; the ρ( T) data for x ≥ 0.1 could be described based on the adiabatic small polaron hopping model.

Crystal structures of ZnCl2·2.5H2O, ZnCl2·3H2O and ZnCl2·4.5H2O

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Erik Hennings

2014-12-01

Full Text Available The formation of different complexes in aqueous solutions is an important step in understanding the behavior of zinc chloride in water. The structure of concentrated ZnCl2 solutions is governed by coordination competition of Cl− and H2O around Zn2+. According to the solid–liquid phase diagram, the title compounds were crystallized below room temperature. The structure of ZnCl2·2.5H2O contains Zn2+ both in a tetrahedral coordination with Cl− and in an octahedral environment defined by five water molecules and one Cl− shared with the [ZnCl4]2− unit. Thus, these two different types of Zn2+ cations form isolated units with composition [Zn2Cl4(H2O5] (pentaaqua-μ-chlorido-trichloridodizinc. The trihydrate {hexaaquazinc tetrachloridozinc, [Zn(H2O6][ZnCl4]}, consists of three different Zn2+ cations, one of which is tetrahedrally coordinated by four Cl− anions. The two other Zn2+ cations are each located on an inversion centre and are octahedrally surrounded by water molecules. The [ZnCl4] tetrahedra and [Zn(H2O6] octahedra are arranged in alternating rows parallel to [001]. The structure of the 4.5-hydrate {hexaaquazinc tetrachloridozinc trihydrate, [Zn(H2O6][ZnCl4]·3H2O}, consists of isolated octahedral [Zn(H2O6] and tetrahedral [ZnCl4] units, as well as additional lattice water molecules. O—H...O hydrogen bonds between the water molecules as donor and ZnCl4 tetrahedra and water molecules as acceptor groups leads to the formation of a three-dimensional network in each of the three structures.

Low-temperature synthesis of single-phase Co7Sb2O12

International Nuclear Information System (INIS)

Brito, M.S.L.; Escote, M.T.; Santos, C.O.P.; Lisboa-Filho, P.N.; Leite, E.R.; Oliveira, J.B.L.; Gama, L.; Longo, E.

2004-01-01

Polycrystalline Co 7 Sb 2 O 12 compounds have been synthesized by a chemical route, which is based on a modified polymeric precursor method. In order to study the physical properties of the samples, X-ray diffraction (XRD), thermal analyses (TG and DSC), infrared spectroscopy (IR), specific surface area (BET), and magnetization measurements were performed on these materials. Characterization through XRD revealed that the samples are single-phase after a heat-treatment at 1100 deg. C for 2 h, while the X-ray patterns of the samples heat-treated at lower temperatures revealed the presence of additional Bragg reflections belonging to the Co 6 Sb 2 O 6 phase. These data were analyzed by means of Rietveld refinement and further analyze showed that Co 7 Sb 2 O 12 displays an inverse spinel crystalline structure. In this structure, the Co 2+ ions occupy the eight tetrahedral positions, and the sixteen octahedral positions are randomly occupied by the Sb 5+ and Co 2+ ions. IR studies disclosed two strong absorption bands, ν 1 and ν 2 , in the expected spectral range for a spinel-type binary oxide with space group Fd3m. Exploratory studies concerning the magnetic properties indicated that this sample presents a spin-glass transition at T f ∼ 64 K

4-[4-(4-Fluorophenyl-2-methyl-5-oxo-2,5-dihydroisoxazol-3-yl]-1-methylpyridinium iodide–4-[3-(4-fluorophenyl-2-methyl-5-oxo-2,5-dihydroisoxazol-4-yl]-1-methylpyridinium iodide (0.6/0.4

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Simona Margutti

2008-01-01

Full Text Available The crystal structure of the title compound, C16H16FN2O2+·I−, was determined as part of a study of the biological activity of isoxazolone derivatives as p38 mitogen-activated protein kinase (MAPK inhibitors. The X-ray crystal structure of 4-[4-(4-fluorophenyl-2-methyl-5-oxo-2,5-dihydroisoxazol-3-yl]-1-methylpyridinium iodide showed the presence of the regioisomer 4-[3-(4-fluorophenyl-2-methyl-5-oxo-2,5-dihydroisoxazol-4-yl]-1-methylpyridinium iodide. The synthesis of the former compound was achieved by reacting 4-(4-fluorophenyl-3-(4-pyridylisoxazol-5(2H-one after treatment with Et3N in dimethylformamide, with iodomethane. The unexpected formation of the regioisomer could be explained by a rearrangement occurring via aziridine of the isoxazolone compound. The regioisomers have site occupancies of 0.632 (4/0.368 (4. The two six members rings make a dihedral angle of 66.8 (2°.

Probing the magnetic ground state of single crystalline Ce3TiSb5

Science.gov (United States)

Matin, M.; Kulkarni, R.; Thamizhavel, A.; Dhar, S. K.; Provino, A.; Manfrinetti, P.

2017-04-01

Motivated by the report of superconductivity in R3TiSb5 (R  =  La and Ce) and possibly Nd3TiSb5 at  ∼4 K, we grew single crystals of La3TiSb5 and Ce3TiSb5 by the high-temperature solution method using Sn as a flux. While in both compounds we observed a superconducting transition at 3.7 K for resistivity and low-field magnetization, our data conclusively show that it arose from residual Sn flux present in the single crystals. In particular, the heat capacity data do not present any of the anomalies expected from a bulk superconducting transition. The anisotropic magnetic properties of Ce3TiSb5, crystallizing in a hexagonal P63/mcm structure, were studied in detail. We find that the Ce ions in Ce3TiSb5 form a Kondo lattice and exhibited antiferromagnetic ordering at 5.5 K with a reduced moment and a moderately normalized Sommerfeld coefficient of 598 mJ/mol K2. The characteristic single-ion Kondo energy scale was found to be  ∼8 K. The magnetization data were subjected to a crystal electric field (CEF) analysis. The experimentally observed Schottky peak in the 4f-electron heat capacity of Ce3TiSb5 was reproduced fairly well by the energy levels derived from the CEF analysis.

Structural modulation and luminescent properties of four Cd{sup II} coordination architectures based on 3-(pyridin-4-yl)-5-(pyrazin-2-yl)-1H-1,2,4-triazole and flexible/rigid dicarboxylate ligands

Energy Technology Data Exchange (ETDEWEB)

Xia, Liang; Dong, Wen-Wen, E-mail: dongww1@126.com; Ye, Xiao; Zhao, Jun; Li, Dong-Sheng, E-mail: lidongsheng1@126.com

2016-10-15

To systematically investigate the influence of the flexible or rigid auxiliary ligands on the structures and properties of transition metal compounds, we synthesized four new d{sup 10} coordination polymers (CPs) from 3-(pyridin-4-yl)-5-(pyrazin-2-yl)-1H-1,2,4-triazole (4-Hpzpt) and flexible/rigid dicarboxylate ligands, [Cd(4-pzpt){sub 2}]{sub n} (1), [Cd{sub 3}(4-pzpt){sub 2}(suc){sub 2}]{sub n} (2), [Cd{sub 2}(4-Hpzpt)(nbc){sub 2}(H{sub 2}O)]{sub n} (3) and ([Cd{sub 2}(4-pzpt){sub 2}(tfbdc)(H{sub 2}O){sub 4}]·H{sub 2}O){sub n} (4) (H{sub 2}suc=1,2-ethanedicarboxylic acid, H{sub 2}nbc=hthalene-1,4-dicarboxylic acid, H{sub 2}tfbdc =2,3,5,6-tetrafluoroterephthalic acid). Single crystal X-ray analysis indicates that compound 1 shows a 4{sup 4}-sql layer, which is extended to a 3D network via nonclassical C–H{sup …}N hydrogen bonds. Compound 2 possesses a 6-connected pcu-4{sup 12}0.6{sup 3} net composed of trinuclear Cd{sup II}-clusters. Compound 3 represents a rare 3D (3,4,4,5)-connected topology with a Schläfli symbol of (4·6·7)(4·5{sup 3}·7{sup 2})(5{sup 3}·6·7·9)(4{sup 2}·5{sup 5}·6·7{sup 2}). Compound 4 exhibits a 2D+2D→2D parallel interpenetrated 6{sup 3}-hcb network. The adjacent 2D networks are interdigitated with each other to form the resulting 3D supramolecular architecture through classical O–H{sup …}N and O–H{sup …}O hydrogen bonds. Structural diversities indicate that the nature of flexible/rigid-dicarboxlates plays crucial roles in modulating structures of these compounds. Moreover, the luminescent properties of them have been briefly investigated. - Graphical abstract: Four new Cd{sup II} coordination architectures constructed from the primary ligand 4-Hpzpt and flexible/rigid dicarboxylate coligands. Structural diversities indicate that the nature of flexible/rigid-dicarboxlates plays crucial roles in modulating structures of these compounds. And more, the thermal stability and luminescence are discussed. - Highlights: �

Na/sub 3/Sb/sub 3/As/sub 2/O/sub 14/: An arsenic antimonate with intersecting tunnels

Energy Technology Data Exchange (ETDEWEB)

Haddad, A.; Jouini, T.; Ghedira, M.

1988-07-15

Na/sub 3/Sb/sub 3/As/sub 2/O/sub 14/, M/sub r/=808.06, monoclinic, P2/sub 1//a, a=12.67(4), b=7.31(1), c=6.52(1) A, ..beta..=107.1(2)/sup 0/, V=577.17 A/sup 3/, Z=2, D/sub m/=4.603 (in bromobenzene), D/sub x/=4.618 Mg m/sup -3/, ..mu../sub Mo/=13.18 mm/sup -1/ F(000)=728. The final R and wR values are 0.0359 and 0.0422 respectively for 845 unique reflections. This structure consists of sheets of corner-sharing SbO/sub 6/ octahedra linked together by AsO/sub 4/ tetrahedra to form a continuous three-dimensional skeleton with intersecting b-axis and c-axis tunnels. The Na/sup +/(1) ions are located at the intersections of these two tunnels and the Na/sup +/(2) ions in the tunnel running along c. The replacement of the Na/sup +/ ions by K/sup +/ results in a modification of the structure which is discussed, and leads to the compound K/sub 3/Sb/sub 3/As/sub 2/O/sub 14/ isotypic to the corresponding phosphate. The title compound exhibits ion exchange properties in an acid aqueous solution.

{2-[(3,5-Dichloro-2-oxidobenzylideneamino-κ2N,O]-3-methylpentanoato-κO}(N,N′-dimethylformamide-κOcopper(II

Directory of Open Access Journals (Sweden)

Xiao Zhen Feng

2008-05-01

Full Text Available In the title compound, [Cu(C13H13Cl2NO3(C3H7NO], the CuII atom is coordinated in a slightly distorted square-planar geometry by two O atoms and one N atom from the tridentate chiral ligand 2-[(3,5-dichloro-2-oxidobenzylideneamino]-3-methylpentanoate and by one O atom from dimethylformamide. In the crystal structure, the Cu atom forms contacts with Cl and O atoms of two units (Cu...Cl and Cu...O = 3.401 and 2.947 Å, respectively, thereby forming an approximately octahedral arrangement. A three-dimensional network is constructed through Cl...Cu, O...Cu, Cl...Cl contacts and C—H...O hydrogen bonds.

5-[3-(2,5-Dimethoxyphenylprop-2-enylidene]-1,3-diethyl-2-thioxohexahydropyrimidine-4,6-dione

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Abdullah Mohamed Asiri

2009-08-01

Full Text Available 1,3-Diethyl-2-thiobarbituric acid reacts with 2,5-dimethoxybenzaldehyde to form the title Knoevenagel product, C19H22N2O4S. In the compound, the two six-membered rings at either end of the three-membered –CHCHCH– chain are nearly coplanar with this fragment (r.m.s. deviation of the two six-membered rings and the three chain atoms = 0.08 Å.

Crystal structures of [SbF{sub 6}]{sup -} salts of di- and tetrahydrated Ag{sup +}, tetrahydrated Pd{sup 2+} and hexahydrated Cd{sup 2+} cations

Energy Technology Data Exchange (ETDEWEB)

Mazej, Zoran; Goreshnik, Evgeny [Jozef Stefan Institute, Ljubljana (Slovenia). Dept. of Inorganic Chemistry and Technology

2017-07-01

The [Ag(H{sub 2}O){sub 2}]SbF{sub 6}, is triclinic, P anti 1 (No. 2), with a=6.6419(3) Aa, b=7.6327(3) Aa, c=11.1338(3) Aa, α=95.492(3) , β=96.994(3) , γ=113.535(4) , V=507.13(4) Aa{sup 3} at 150 K, and Z=3. There are two crystallographically non-equivalent Ag{sup +} cations. The Ag1 is coordinated by two water molecules with Ag-OH{sub 2} distances equal to 2.271(2) Aa forming in that way a discrete linear [Ag(H{sub 2}O){sub 2}]{sup +} cation. Additionaly, it forms two short Ag..F contacts (2.630(2) Aa), resulting in AgO{sub 2}F{sub 2} plaquette, and four long ones (2 x 3.001(2) Aa and 2 x 3.095(2) Aa) with fluorine atoms located below and above the AgO{sub 2}F{sub 2} plaquette. The H{sub 2}O molecules bridge Ag2 atoms into {-[Ag(μ-OH_2)_2]-}{sub n} infinite chains, with Ag-O distances of 2.367(2)-2.466(2) Aa. The [Pd(H{sub 2}O){sub 4}](SbF{sub 6}){sub 2}.4H{sub 2}O is monoclinic, P2{sub 1}/a (No.14), with a=8.172(2) Aa, b=13.202(3) Aa, c=8.188(3) Aa, β=115.10(1) , V=799.9(4) Aa{sup 3} at 200 K, and Z=2. Its crystal structure can be described as an alternation of layers of [Pd(H{sub 2}O){sub 4}]{sup 2+} cations (interconnected by H{sub 2}O molecules) and [SbF{sub 6}]{sup -} anions. It represents the first example where [Pd(H{sub 2}O){sub 4}]{sup 2+} has been structurally determined in the solid state. Four oxygen atoms provided by H{sub 2}O molecules are in almost ideal square-planar arrangement with Pd-O bond lengths 2 x 2.004(5) Aa and 2 x 2.022(6) Aa. The [Cd(H{sub 2}O){sub 6}](SbF{sub 6}){sub 2}, is orthorhombic, Pnnm (No.58), with a=5.5331(2) Aa, b=14.5206(4) Aa, c=8.9051(3) Aa, V=715.47(4) Aa{sup 3} at 200 K, and Z=2. It consists of [Cd(H{sub 2}O){sub 6}]{sup 2+} cations and [SbF{sub 6}]{sup -} anions.

The development of new phosphors of Tb3+/Eu3+ co-doped Gd3Al5O12 with tunable emission

Science.gov (United States)

Teng, Xin; Wang, Wenzhi; Cao, Zhentao; Li, Jinkai; Duan, Guangbin; Liu, Zongming

2017-07-01

The gadolinium aluminum garnets Gd3Al5O12 (GdAG) activated with Tb3+/Eu3+ were successfully prepared via co-precipitation method at 1500 °C in this work. The crystal structure stabilization, elements analysis, microphotograph, PL/PLE spectra, decay behavior and quantum efficiency were discussed in detail. The metastable GdAG compounds been effectively stabilized by doping with smaller 10 at.% Tb3+, which then allows the development of new phosphors of (Gd0.9-xTb0.1Eux)3Al5O12 (GdAG:Tb3+/Eu3+, x = 0-0.03) for opto-functionality explorations. The PLE/PL spectra displays that the strongest PLE peak was located at ∼276 nm, which overlaps the 8S7/2 → 6IJ transition of Gd3+. Under 276 nm excitation, the phosphors exhibited both Tb3+ and Eu3+ emissions at 548 nm (green, 5D4 → 7F5 transition of Tb3+) and 592 nm (orange-red, 5D0 → 7F1 transition of Eu3+), respectively. The emission intensities of Tb3+ and Eu3+ remarkably varied with the Eu3+ incorporation. As a consequence, the emission color can be readily tuned from approximately green to orange-red. Fluorescence decay analysis found that the lifetime for the Tb3+ emission rapidly decreased conforming to the Tb3+ → Eu3+ energy transfer, and the energy transfer efficiency was calculated. Owing to the Gd3+ → Eu3+ and Gd3+ → Tb3+ energy transfer, the emission intensities of Tb3+ and Eu3+ in (Gd0.9-xTb0.1Eux)AG phosphor were higher than (Y0.87Tb0.1Eu0.03)AG and (Lu0.87Tb0.1Eu0.03)AG system. The (Gd0.9-xTb0.1Eux)AG garnet phosphors developed in this work may serve as a new type of phosphor which hopefully meets the requirements of various lighting and optical display applications.

(Carbonato-κ(2)O,O')bis-(5,5'-dimethyl-2,2'-bipyridyl-κ(2)N,N')cobalt(III) bromide trihydrate.

Science.gov (United States)

Arun Kumar, Kannan; Meera, Parthsarathi; Amutha Selvi, Madhavan; Dayalan, Arunachalam

2012-04-01

In the title complex, [Co(CO(3))(C(12)H(12)N(2))(2)]Br·3H(2)O, the Co(III) cation has a distorted octa-hedral coordination environment. It is chelated by four N atoms of two different 5,5'-dimethyl-2,2'-bipyridyl (dmbpy) ligands in axial and equatorial positions, and by two O atoms of a carbonate anion completing the equatorial positions. Although the water mol-ecules are disordered and their H atoms were not located, there are typical O⋯O distances between 2.8 and 3.0 Å, indicating O-H⋯O hydrogen bonding. The crystal packing is consolidated by C-H⋯O and C-H⋯Br hydrogen bonds, as well as π-π stacking inter-actions between adjacent pyridine rings of the dmbpy ligands, with centroid-centroid distances of 3.694 (3) and 3.7053 (3) Å.

Simultaneous removal of Cd(II) and Sb(V) by Fe–Mn binary oxide: Positive effects of Cd(II) on Sb(V) adsorption

Energy Technology Data Exchange (ETDEWEB)

Liu, Ruiping [Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Liu, Feng [Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Hu, Chengzhi, E-mail: czhu@rcees.ac.cn [Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); He, Zan [Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Liu, Huijuan; Qu, Jiuhui [Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China)

2015-12-30

Highlights: • Fe–Mn binary oxide achieves the simultaneous removal of Cd(II) and Sb(V). • Cd(II) at above 0.25 mmol/L improves Sb(V) adsorption onto FMBO. • Cd(II) improves more significant Sb(V) adsorption than Ca{sup 2+} and Mn{sup 2+}. • Sb(V) adsorption decreases whereas Cd(II) adsorption increases with elevated pH. • The increased ζ-potential and Cd(II)–Sb(V) precipitation favors Sb(V) adsorption. - Abstract: The coexistence of cadmium ion (Cd(II)) and antimonate (Sb(V)) creates the need for their simultaneous removal. This study aims to investigate the effects of positively-charged Cd(II) on the removal of negative Sb(V) ions by Fe–Mn binary oxide (FMBO) and associated mechanisms. The maximum Sb(V) adsorption density (Q{sub max,Sb(V)}) increased from 1.02 to 1.32 and 2.01 mmol/g in the presence of Cd(II) at 0.25 and 0.50 mmol/L. Cd{sup 2+} exhibited a more significant positive effect than both calcium ion (Ca{sup 2+}) and manganese ion (Mn{sup 2+}). Cd{sup 2+} showed higher affinity towards FMBO and increased its ζ-potential more significantly compared to Ca{sup 2+} and Mn{sup 2+}. The simultaneous adsorption of Sb(V) and Cd(II) onto FMBO can be achieved over a wide initial pH (pH{sub i}) range from 2 to 9, and Q{sub Sb(V)} decreases whereas Q{sub Cd(II)} increases with elevated pH{sub i}. Their combined values, as expressed by Q{sub Sb(V)+Cd(II)}, amount to about 2 mmol/g and vary slightly in the pH{sub i} range 4–9. FTIR and XPS spectra indicate the significant synergistic effect of Cd(II) on Sb(V) adsorption onto FMBO, and that little chemical valence transformation occurs. These results may be valuable for the treatment of wastewater with coexisting heavy metals such as Cd(II) and Sb(V).

Synthesis process and structural characterization of the Sr{sub 2}EuRuO{sub 6} complex perovskite

Energy Technology Data Exchange (ETDEWEB)

Triana, C.A.; Landinez Tellez, D.A. [Grupo de Fisica de Nuevos Materiales (GFNM), Departamento de Fisica, Universidad Nacional de Colombia, Bogota D.C. A.A. 5997 (Colombia); Roa-Rojas, J., E-mail: jroar@unal.edu.co [Grupo de Fisica de Nuevos Materiales (GFNM), Departamento de Fisica, Universidad Nacional de Colombia, Bogota D.C. A.A. 5997 (Colombia)

2012-03-05

Highlights: Black-Right-Pointing-Pointer Crystal structure, surface morphology and composition of Sr{sub 2}EuRuO{sub 6} have been studied. Black-Right-Pointing-Pointer Sr{sub 2}EuRuO{sub 6} crystallize in a monoclinic perovskite-type structure in P2{sub 1}/n space group. Black-Right-Pointing-Pointer Ru{sup 5+} and Eu{sup 3+} ions are on the six coordinate M sites, Sr{sup 2+} is located in the A-site. Black-Right-Pointing-Pointer Scanning electron microscopy and Scherrer formula shows a particle size of D = 34.2 nm. Black-Right-Pointing-Pointer Activation energy Q through the Arrhenius plot for Sr{sub 2}EuRuO{sub 6} is close to 39.6 kJ/mol. - Abstract: The Sr{sub 2}EuRuO{sub 6} complex perovskite has been synthesized by the solid-state reaction method and the crystal structure, surface morphology and composition have been investigated. Results of powder X-ray diffraction measurements and Rietveld analysis show that this compound crystallizes in a monoclinic distorted perovskite-type structure, which belongs to the monoclinic P2{sub 1}/n (no. 14) space group, that corresponds to the (a{sup +}b{sup -}b{sup -}) tilt system on the Glazer notation. The structure presents an alternating distribution of the Ru{sup 5+} and Eu{sup 3+} ions on the six coordinate M sites, while the Sr{sup 2+} is located in the A-site of the Sr{sub 2}EuRuO{sub 6} complex perovskite, with lattice parameters a = 5.7996(5) Angstrom-Sign , b = 5.8960(7) Angstrom-Sign , c = 8.3234(6) Angstrom-Sign , angle {beta} = 90.234(7) Degree-Sign and V = 284.61(4) Angstrom-Sign {sup 3}. Morphological analysis of this material, performed by scanning electron microscopy (SEM), allows to establish the granular feature of compound with agglomerates from amongst Almost-Equal-To 1 to 3 {mu}m size, and by means of the Scherrer formula was calculated a particle size of D = 34.2 nm. Result suggests that crystal structure of the Sr{sub 2}EuRuO{sub 6} suffers grain size-induced polarization rotation, which produces a

Preparation, photoluminescent properties and luminescent dynamics of BaAlF5:Eu2+ nanophosphors

International Nuclear Information System (INIS)

Zhang, Wei; Hua, Ruinian; Liu, Tianqing; Zhao, Jun; Na, Liyan; Chen, Baojiu

2014-01-01

Graphical abstract: Rice-shaped BaAlF 5 :Eu 2+ nanophosphors were synthesized via one-pot hydrothermal process. The as-prepared BaAlF 5 :Eu 2+ are composed of many particles with an average diameter of 40 nm. When excited at 260 nm, the sharp line emission located at 361 nm of Eu 2+ was observed. The optimum doping concentration of Eu 2+ was confirmed to be 5 mol%. The strong ultraviolet emission of Eu 2+ ions in BaAlF 5 :Eu 2+ nanoparticles suggests that these nanoparticles may have potential applications for sensing, solid-state lasers and spectrometer calibration. - Highlights: • BaAlF 5 :Eu 2+ nanophosphors were synthesized via a mild hydrothermal process. • The Van and Huang models were used to research the mechanism of concentration quenching. • The optimum doping concentration of Eu2+ was confirmed to be 5 mol%. - Abstract: Eu 2+ -doped BaAlF 5 nanophosphors were synthesized via a facile one-pot hydrothermal method. The final products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and photoluminescence (PL) spectroscopy. XRD results showed that the prepared samples are single-phase. The FE-SEM and TEM images indicated that the prepared BaAlF 5 :Eu 2+ nanophosphors are composed of many rice-shaped particles with an average diameter of 40 nm. When excited at 260 nm, BaAlF 5 :Eu 2+ nanophosphors exhibit the sharp line emissions of Eu 2+ at room temperature. The optimum doping concentration of Eu 2+ was confirmed to be 5 mol%. The Van and Huang models were used to study the mechanism of concentration quenching and the electric dipole–dipole interaction between Eu 2+ can be deduced to be a dominant for quenching fluorescence in BaAlF 5 :Eu 2+ nanophosphors. The strong ultraviolet emission of Eu 2+ in BaAlF 5 :Eu 2+ nanophosphors suggests that these nanoparticles may have potential applications for sensing, spectrometer calibration and solid-state lasers

Study of chromites YbMIICr2O5,5 (MII - Mg, Ca, Sr, Ba by X-ray diffraction

Directory of Open Access Journals (Sweden)

B. Kasenov

2012-03-01

Full Text Available Compounds of composition YbMeMnFeO5,5 (Me – Mg, Ca, Sr, Ba are synthesized from Yb2O3, , Cr2O3 and MgCO3, CaCO3, SrCO3, BaCO3 by solid phase method. X-ray powder diffraction showed that the compound YbMgCr2O5,5, YbCaCr2O5,5, YbSrCr2O5,5, YbBaCr2O5,5 crystallizes in the tetragonal crystal system.

Poly[[aqua(μ2-4,4′-bipyridine-κ2N:N′[μ3-3-bromo-2-(carboxylatomethylbenzoato-κ3O1:O1′:O2]cadmium] monohydrate

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Yangmei Liu

2012-08-01

Full Text Available In the title compound, {[Cd(C9H5BrO4(C10H8N2(H2O]·H2O}n, the CdII atom has a distorted octahedral coordination geometry. Two N atoms from two 4,4′-bipyridine (bipy ligands occupy the axial positions, while the equatorial positions are furnished by three carboxylate O atoms from three 3-bromo-2-(carboxylatomethylbenzoate (bcb ligands and one O atom from a water molecule. The bipy and bcb ligands link the CdII atoms into a three-dimensional network. O—H...O hydrogen bonds and π–π interactions between the pyridine and benzene rings [centroid–centroid distance = 3.736 (4 Å] are present in the crystal.

Structural modulation and luminescent properties of four CdII coordination architectures based on 3-(pyridin-4-yl)-5-(pyrazin-2-yl)-1H-1,2,4-triazole and flexible/rigid dicarboxylate ligands

Science.gov (United States)

Xia, Liang; Dong, Wen-Wen; Ye, Xiao; Zhao, Jun; Li, Dong-Sheng

2016-10-01

To systematically investigate the influence of the flexible or rigid auxiliary ligands on the structures and properties of transition metal compounds, we synthesized four new d10 coordination polymers (CPs) from 3-(pyridin-4-yl)-5-(pyrazin-2-yl)-1H-1,2,4-triazole (4-Hpzpt) and flexible/rigid dicarboxylate ligands, [Cd(4-pzpt)2]n (1), [Cd3(4-pzpt)2(suc)2]n (2), [Cd2(4-Hpzpt)(nbc)2(H2O)]n (3) and {[Cd2(4-pzpt)2(tfbdc)(H2O)4]·H2O}n (4) (H2suc=1,2-ethanedicarboxylic acid, H2nbc=hthalene-1,4-dicarboxylic acid, H2tfbdc =2,3,5,6-tetrafluoroterephthalic acid). Single crystal X-ray analysis indicates that compound 1 shows a 44-sql layer, which is extended to a 3D network via nonclassical C-H…N hydrogen bonds. Compound 2 possesses a 6-connected pcu-4120.63 net composed of trinuclear CdII-clusters. Compound 3 represents a rare 3D (3,4,4,5)-connected topology with a Schläfli symbol of (4·6·7)(4·53·72)(53·6·7·9)(42·55·6·72). Compound 4 exhibits a 2D+2D→2D parallel interpenetrated 63-hcb network. The adjacent 2D networks are interdigitated with each other to form the resulting 3D supramolecular architecture through classical O-H…N and O-H…O hydrogen bonds. Structural diversities indicate that the nature of flexible/rigid-dicarboxlates plays crucial roles in modulating structures of these compounds. Moreover, the luminescent properties of them have been briefly investigated.

Eu{sub 7}Ga{sub 6}Sb{sub 8}: A Zintl phase with Ga-Ga bonds and polymeric gallium antimonide chains

Energy Technology Data Exchange (ETDEWEB)

Park, S -M; Kim, S -J; Kanatzidis, M G

2004-08-01

The Zintl phase Eu{sub 7}Ga{sub 6}Sb{sub 8} was obtained from a direct element combination reaction at 900 deg. C. It crystallizes in the orthorhombic space group Pbca (No. 61) with a=15.6470(17) A, b=17.2876(19) A, c=17.9200(19) A, and Z=8. In Eu{sub 7}Ga{sub 6}Sb{sub 8}, the anionic framework forms infinite chains of [Ga{sub 6}Sb{sub 8}]{sup 14-} which are arranged side by side to make a sheet-like arrangement but without linking. The sheets of chains are separated by Eu{sup 2+} atoms and also within the sheet, Eu{sup 2+} atoms fill the spaces between two chains. The chain is made up of homoatomic tetramers (Ga{sub 4}){sup 6+} and dimers (Ga{sub 2}){sup 4+} connected by Sb atoms. The compound is a narrow band-gap semiconductor with E{sub g}{approx}0.6 eV and satisfies the classical Zintl concept. Extended Hueckel band structure calculations confirm that the material is a semiconductor and suggest that the structure is stabilized by strong Ga-Ga covalent bonding interactions. Magnetic susceptibility measurements for Eu{sub 7}Ga{sub 6}Sb{sub 8} show that the Eu atoms are divalent and the compound has an antiferromagnetic transition at 9 K.

Preparation and crystal structure of Ca/sub 4/Sb/sub 2/O

Energy Technology Data Exchange (ETDEWEB)

Eisenmann, B; Limartha, H; Schaefer, H; Graf, H A

1980-12-01

The formerly described compound Ca/sub 2/Sb is to be corrected to Ca/sub 4/Sb/sub 2/O as shown by X-ray diffractometer data of single crystals and neutron diffraction diagrams of powders. The compound crystallizes in the K/sub 2/NiF/sub 4/ type structure.

2-Methylsulfanyl-5,6-dihydro-2H-1,3-dithiolo[4,5-b][1,4]dioxin-2-ium tetrafluoroborate

Directory of Open Access Journals (Sweden)

Guoquan Zhou

2012-04-01

Full Text Available The title compound, C6H7O2S3+·BF4−, consists of a planar 2-thioxo-1,3-dithiol-4,5-yl unit [maximum deviation from the ring plane = 0.020 (3 Å], with an ethylenedioxy group fused at the 4,5-positions; the ethylenedioxy C atoms are disordered over two positions with site-occupancy factors of 0.5. The 1,4-dioxine ring has a twist-chair conformation. Weak cation–anion S...F interactions [3.022 (4–3.095 (4 Å] and an S...O [3.247 (4 Å] interaction are present.

Effect of Se substitution on the phase change properties of Ge2Sb2Te5

Science.gov (United States)

Shekhawat, Roopali; Rangappa, Ramanna; Gopal, E. S. R.; Ramesh, K.

2018-05-01

Ge2Sb2Te5 popularly known as GST is being explored for non-volatile phase change random access memory(PCRAM) applications. Under high electric field, thin films of amorphous GST undergo a phase change from amorphous to crystalline with a high contrast in electrical resistivity (about 103). The phase change is between amorphous and metastable NaCl structure occurs at about 150°C and not to the stable hexagonal phase which occurs at a high temperature (> 250 °C). In GST, about 50 % of Te substituted by Se (Ge2Sb2Te2.5Se2.5) is found to increase the contrast in electrical resistivity by 7 orders of magnitude (about 4 orders of magnitude higher than GST). The phase transition in Se added GST also found to be between amorphous and the stable hexagonal structure. The threshold voltage at which the Ge2Sb2Te2.5Se2.5 switches to the high conducting state increases to 9V as compared to 2V in GST. Interestingly, the threshold current decrease to 1mA as compared to 1.8mA in GST indicating the Se substitution reduces the power needed for switching between the low and high conducting states. The reduction in power needed for phase change, high contrast in electrical resistivity with high thermal stability makes Ge2Sb2Te2.5Se2.5 as a better candidate for PCRAM.

Preparation and observation of an artifact-free Ge2Sb2Te5 TEM specimen by the small angle cleavage technique

International Nuclear Information System (INIS)

Kim, M.S.; Kim, H.G.

2006-01-01

The amorphous Ge 2 Sb 2 Te 5 thin film for the application to the non-volatile memory device was prepared by the pulsed laser deposition on a SiO2/Si substrate. The amorphous Ge 2 Sb 2 Te 5 which has the T C around 150 deg. C is readily crystallized when exposed to a comparable heat such as the Ar beam irradiation during the conventional ion milling process. Retaining its amorphous initial phase is important in order to precisely observe and understand the crystallization behaviour whether it be the sample for a pure materialistic research or applied into the device. To avoid such deterioration of the film's amorphous nature, the complete mechanical TEM specimen preparation which is called the small angle cleavage technique (SACT) was adopted to show thermally undisturbed, an artifact-free amorphous Ge 2 Sb 2 Te 5 TEM specimen. The two distinctive amorphous and crystalline phases has been observed by the HRTEM study

Síntesis hidrotermal de monocristales LnMn2O5 (Ln= Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho y Er

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Señarís Rodríguez, M. A.

2008-08-01

Full Text Available Ten single crystals of the series LnMn2O5 (Ln= Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho and Er were synthesized by hydrothermal synthesis in a single step and without subsequent thermal treatments from aqueous solutions of metals salts at 240 ºC. The obtained single crystals have a size of various micrometers and their morphology changes throughout the serie: they are polygonal in the case of the compounds with Ln= Pr, Nd, Sm, Eu and Gd and needle-like in the case of the compounds with Ln= Y, Tb, Dy, Ho and Er. After the analysis of the obtained products employing different conditions of synthesis we attributed the different morphology to a greater growth rate along the c axis when the smaller ions (Y, Tb, Dy, Ho y Er are involved, due to their better adaptation to the compound’s crystal structure.Se han conseguido preparar monocristales de 10 óxidos mixtos de la serie LnMn2O5 (Ln= Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho y Er mediante síntesis hidrotermal optimizada, en un único paso y sin tratamientos térmicos posteriores partiendo de las correspondientes sales metálicas en disolución acuosa a 240 ºC. Los monocristales obtenidos son relativamente grandes, de varias micras y su morfología varía a lo largo de la serie: es poligonal en el caso de los compuestos de los lantánidos del inicio de la serie (Ln= Pr, Nd, Sm, Eu y Gd y acicular en el caso de los compuestos de Y y de los lantánidos del final de la serie (Ln= Tb, Dy, Ho y Er. Tras el análisis de los productos obtenidos empleando distintas condiciones de síntesis atribuimos la diferente morfología a una mayor velocidad de crecimiento cristalino a lo largo del eje c cuando intervienen los iones más pequeños (Y, Tb, Dy, Ho y Er debido a la mejor adaptación de éstos últimos a la estructura cristalina del compuesto.

Crystal structure of 2-(thiophen-2-yl)-1-(5-thioxo-4,5-dihydro-1,3,4-oxadiazol-2-yl) ethenyl]benzamide: N,N-dimethylformamide (1 : 1)

Energy Technology Data Exchange (ETDEWEB)

Sharma, P. [University of Jammu, X-ray Crystallography Laboratory, Department of Physics (India); Subbulakshmi, K. N.; Narayana, B. [Mangalore University, Department of Chemistry (India); Sarojini, B. K. [Mangalore University, Industrial Chemistry Division, Department of Studies in Chemistry (India); Kant, R., E-mail: rkant.ju@gmail.com [University of Jammu, X-ray Crystallography Laboratory, Department of Physics (India)

2016-03-15

The title compound, 2-(thiophen-2-yl)-1-(5-thioxo-4,5-dihydro-1,3,4-oxadiazol-2-yl)ethenyl] benzamide:N,N-dimethylformamide (1: 1), (C{sub 15}H{sub 11}N{sub 3}O{sub 2}S{sub 2} · C{sub 3}H{sub 7}NO), was synthesized, and its structure was established by spectral analysis and X-ray diffraction studies. The compound crystallizes in the monoclinic space group P2{sub 1}/n with a = 10.8714(7), b = 9.0497(5), c = 19.8347(13) Å, β = 91.093(5)°, Z = 4. The crystal structure is stabilized by N–H···S, C–H···O and N–H···O hydrogen bonds. The π···π interactions are also observed between the rings.

Microstructures and thermoelectric properties of GeSbTe based layered compounds

Energy Technology Data Exchange (ETDEWEB)

Yan, F.; Zhu, T.J.; Zhao, X.B. [Zhejiang University, State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Hangzhou (China); Dong, S.R. [Zhejiang University, Department of Information and Electronics Engineering, Hangzhou (China)

2007-08-15

Microstructures and thermoelectric properties of Ge{sub 1}Sb{sub 2}Te{sub 4} and Ge{sub 2}Sb{sub 2}Te{sub 5} chalcogenide semiconductors have been investigated to explore the possibility of their thermoelectric applications. The phase transformation from the face-centered cubic to hexagonal structure was observed in Ge{sub 2}Sb{sub 2}Te{sub 5} compounds prepared by the melt spinning technique. The Seebeck coefficient and electrical resistivity of the alloys were increased due to the enhanced scattering of charge carriers at grain boundaries. The maximum power factors of the rapidly solidified Ge{sub 1}Sb{sub 2}Te{sub 4} and Ge{sub 2}Sb{sub 2}Te{sub 5} attained 0.975 x 10{sup -3} Wm{sup -1}K{sup -2} at 750 K and 0.767 x 10{sup -3} Wm{sup -1}K{sup -2} at 643 K respectively, higher than those of water quenched counterparts, implying that thermoelectric properties of GeSbTe based layered compounds can be improved by grain refinement. The present results show this class of chalcogenide semiconductors is promising for thermoelectric applications. (orig.)

Optical Properties of Al- and Sb-Doped CdTe Thin Films

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A. A. J. Al-Douri

2010-01-01

Full Text Available Nondoped and (Al, Sb-doped CdTe thin films with 0.5, 1.5, and 2.5  wt.%, respectively, were deposited by thermal evaporation technique under vacuum onto Corning 7059 glass at substrate temperatures ( of room temperature (RT and 423 K. The optical properties of deposited CdTe films such as band gap, refractive index (n, extinction coefficient (, and dielectric coefficients were investigated as function of Al and Sb wt.% doping, respectively. The results showed that films have direct optical transition. Increasing and the wt.% of both types of dopant, the band gap decrease but the optical is constant as n, and real and imaginary parts of the dielectric coefficient increase.

N′-(3,5-Dibromo-2-hydroxybenzylidene-2-methylbenzohydrazide

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Chun-Bao Tang

2010-12-01

Full Text Available The asymmetric unit of the title compound, C15H12Br2N2O2, contains two independent molecules in which the dihedral angles between the benzene rings are 49.5 (7 and 66.4 (7°. Intramolecular O—H...N hydrogen bonds generate S(6 ring motifs in each molecule. In the crystal, molecules are linked through intermolecular N—H...O hydrogen bonds, forming chains along the b axis.

Effect of mixing RE elements (Nd, Sm, Gd, Eu, Y, Yb) on the RE2BaCuO5/Nd4-2xBa2+2xCu2-xO10-2x phases in RE cuprate high-Tc superconductors

International Nuclear Information System (INIS)

Langhorn, J.B.; Black, M.A.; McGinn, P.J.

1999-01-01

The phases RE 2 BaCuO 5 /RE 4 Ba 2 Cu 2 O 10 phases (where RE is a mixture of Nd, Sm, Gd, Eu, Y and Yb) have been synthesized in an oxygen atmosphere and subsequently characterized. The mixing of RE elements which inherently form the RE 2 BaCuO 5 phase through the peritectic decomposition of REBa 2 Cu 3 O 7-x (RE123) (i.e. Sm, Gd, Eu, Y, Yb), was observed to give homogeneous mixing of the elements in the 211 phase. In contrast it was found that on mixing Nd with other RE elements a mixture of the Nd 4-2x Ba 2+2x Cu 2-x O 10-2x (Nd422) and RE 2 BaCuO 5 (RE211) phases resulted. It was also observed that on mixing Nd with other REs a finite amount of the RE is substituted into the Nd422 phase and Nd into the RE211. (author)

Thermoelectric properties of c-GeSb{sub 0.75}Te{sub 0.5} to h-GeSbTe{sub 0.5} thin films through annealing treatment effects

Energy Technology Data Exchange (ETDEWEB)

Vora-ud, Athorn, E-mail: athornvora-ud@snru.ac.th [Program of Physics, Faculty of Science and Technology, Sakon Nakhon Rajabhat University, Mueang District, Sakon Nakhon 47000 (Thailand); Thermoelectrics Research Center, Research and Development Institution, Sakon Nakhon Rajabhat University, Mueang District, Sakon Nakhon 47000 (Thailand); Horprathum, Mati, E-mail: mati.horprathum@nectec.or.th [National Electronics and Computer Technology Center, National Science and Technology Development Agency, Pathumthani 12120 (Thailand); Eiamchai, Pitak [National Electronics and Computer Technology Center, National Science and Technology Development Agency, Pathumthani 12120 (Thailand); Muthitamongkol, Pennapa; Chayasombat, Bralee; Thanachayanont, Chanchana [National Metal and Materials Technology Center, National Science and Technology Development Agency, Pathumthani 12120 (Thailand); Pankiew, Apirak [National Electronics and Computer Technology Center, National Science and Technology Development Agency, Pathumthani 12120 (Thailand); Klamchuen, Annop [National Nanotechnology Center, National Science and Technology Development Agency, Pathumthani 12120 (Thailand); Naenkieng, Daengdech; Plirdpring, Theerayuth; Harnwunggmoung, Adul [Thermoelectric and Nanotechnology Research Center, Faculty of Science and Technology, Rajamangala University of Technology Suvarnabhumi, Huntra Phranakhon, Si Ayutthaya 13000 (Thailand); Charoenphakdee, Anek [NANO-Thermoelectrics Research Center, Division of Applied Physics, Faculty of Sciences and Liberal Arts, Rajamangala University of Technology Isan, Mueng Nakorn Ratchasima 30000 Thailand (Thailand); Somkhunthot, Weerasak [Program of Physics, Faculty of Science and Technology, Loei Rajabhat University, Muang District, Loei 42000 (Thailand); and others

2015-11-15

Germanium–Antimony–Tellurium (Ge–Sb–Te) thin films were deposited on silicon wafers with 1-μm silicon dioxide (SiO{sub 2}/Si) by pulsed dc magnetron sputtering from a 99.99% GeSbTe target of 1:1:1 ratio at ambient temperature. The samples were annealed at 573, 623, 673, and 723 K for 3600 s in a vacuum state. The effects of the annealing treatment on phase identification, atomic composition, morphology and film thickness, carrier concentration, mobility, and Seebeck coefficient of the Ge–Sb–Te samples have been investigated by grazing-incidence X-ray diffraction, auger electron spectroscopy, field-emission scanning electron microscopy, Hall-effect measurements, and steady state method, respectively. The results demonstrated that the as-deposited Ge–Sb–Te sample was amorphous. Atomic composition of as-deposited and annealed films at 573 K and 623 K were GeSb{sub 0.75}Te{sub 0.5} while annealed films at 673 K and 723 K were GeSbTe{sub 0.5} due to Sb-rich GeSb{sub 0.75}Te{sub 0.5}. The samples annealed at 573 K and 623 K showed the crystal phases of cubic structure (c-GeSb{sub 0.75}Te{sub 0.5}) into hexagonal structure (h-GeSbTe{sub 0.5}) after annealing at 673 K and 723 K. The study demonstrated the insulating condition from the as-deposited GeSbTe film, and the changes towards the thermoelectric properties from the annealing treatments. The GeSbTe films annealed at 673 K yielded excellent thermoelectric properties with the electrical resistivity, Seebeck coefficient, and power factor at approximately 1.45 × 10{sup −5} Ωm, 71.07 μV K{sup −1}, and 3.48 × 10{sup −4} W m{sup −1} K{sup −2}, respectively. - Highlights: • GeSbTe thin films were successfully sputtered for thermoelectric properties. • GeSbTe films were examined among physical, electrical and thermoelectric properties. • Thermoelectric properties were discussed based on composition of the films.

First-principles study of the amorphous In3SbTe2 phase change compound

Science.gov (United States)

Los, Jan H.; Kühne, Thomas D.; Gabardi, Silvia; Bernasconi, Marco

2013-11-01

Ab initio molecular dynamics simulations based on density functional theory were performed to generate amorphous models of the phase change compound In3SbTe2 by quenching from the melt. In-Sb and In-Te are the most abundant bonds with only a minor fraction of Sb-Te bonds. The bonding geometry in the amorphous phase is, however, strongly dependent on the density in the range 6.448-5.75 g/cm3 that we investigated. While at high density the bonding geometry of In atoms is mostly octahedral-like as in the cubic crystalline phase of the ternary compound In3SbTe2, at low density we observed a sizable fraction of tetrahedral-like geometries similar to those present in the crystalline phase of the two binary compounds InTe and InSb that the ternary system can be thought to be made of. We show that the different ratio between octahedral-like and tetrahedral-like bonding geometries has fingerprints in the optical and vibrational spectra.

Simultaneous removal of Cd(II) and Sb(V) by Fe–Mn binary oxide: Positive effects of Cd(II) on Sb(V) adsorption

International Nuclear Information System (INIS)

Liu, Ruiping; Liu, Feng; Hu, Chengzhi; He, Zan; Liu, Huijuan; Qu, Jiuhui

2015-01-01

Highlights: • Fe–Mn binary oxide achieves the simultaneous removal of Cd(II) and Sb(V). • Cd(II) at above 0.25 mmol/L improves Sb(V) adsorption onto FMBO. • Cd(II) improves more significant Sb(V) adsorption than Ca"2"+ and Mn"2"+. • Sb(V) adsorption decreases whereas Cd(II) adsorption increases with elevated pH. • The increased ζ-potential and Cd(II)–Sb(V) precipitation favors Sb(V) adsorption. - Abstract: The coexistence of cadmium ion (Cd(II)) and antimonate (Sb(V)) creates the need for their simultaneous removal. This study aims to investigate the effects of positively-charged Cd(II) on the removal of negative Sb(V) ions by Fe–Mn binary oxide (FMBO) and associated mechanisms. The maximum Sb(V) adsorption density (Q_m_a_x_,_S_b_(_V_)) increased from 1.02 to 1.32 and 2.01 mmol/g in the presence of Cd(II) at 0.25 and 0.50 mmol/L. Cd"2"+ exhibited a more significant positive effect than both calcium ion (Ca"2"+) and manganese ion (Mn"2"+). Cd"2"+ showed higher affinity towards FMBO and increased its ζ-potential more significantly compared to Ca"2"+ and Mn"2"+. The simultaneous adsorption of Sb(V) and Cd(II) onto FMBO can be achieved over a wide initial pH (pH_i) range from 2 to 9, and Q_S_b_(_V_) decreases whereas Q_C_d_(_I_I_) increases with elevated pH_i. Their combined values, as expressed by Q_S_b_(_V_)_+_C_d_(_I_I_), amount to about 2 mmol/g and vary slightly in the pH_i range 4–9. FTIR and XPS spectra indicate the significant synergistic effect of Cd(II) on Sb(V) adsorption onto FMBO, and that little chemical valence transformation occurs. These results may be valuable for the treatment of wastewater with coexisting heavy metals such as Cd(II) and Sb(V).

Heterogeneous nucleation of Mg2Si on Sr11Sb10 nucleus in Mg–x(3.5, 5 wt.%)Si–1Al alloys

International Nuclear Information System (INIS)

Wang, Hui-Yuan; Chen, Lei; Liu, Bo; Li, Xiao-Ran; Wang, Jin-Guo; Jiang, Qi-Chuan

2012-01-01

After combined additions of Sr and Sb, most primary Mg 2 Si crystals in Mg–3.5Si–1Al and Mg–5Si–1Al alloys transformed from equiaxed-dendritic shapes to octahedral morphologies; while eutectic phases also changed from Chinese script to short rod-shapes. The mechanisms of complex modification of Sr and Sb were attributed to the heterogeneous nucleation of primary Mg 2 Si on Sr 11 Sb 10 nucleus, together with change in growth manners caused by incorporation of Sb in Mg 2 Si crystals. -- Highlights: ► The Sr 11 Sb 10 is the heterogeneous nucleation of primary Mg 2 Si in Mg–3.5Si–1Al alloys. ► Some Sb atoms were incorporated by substituting Si which changed growth manners of primary Mg 2 Si. ► Primary Mg 2 Si transformed from equiaxed-dendritic to octahedral after modification. ► Eutectic phases changed from Chinese script to short rod-shapes after modification.

Electric Field-Induced Large Strain in Ni/Sb-co Doped (Bi0.5Na0.5) TiO3-Based Lead-Free Ceramics

Science.gov (United States)

Li, Liangliang; Hao, Jigong; Xu, Zhijun; Li, Wei; Chu, Ruiqing

2018-02-01

Lead-free piezoelectric ceramics (Bi0.5Na0.5)0.935Ba0.065Ti1- x (Ni0.5Sb0.5) x O3 (BNBT6.5- xNS) have been fabricated using conventional solid sintering technique. The effect of (Ni, Sb) doping on the phase structure and electrical properties of BNBT6.5 ceramics were systematically investigated. Results show that the addition of (Ni, Sb) destroyed the ferroelectric long-range order of BNBT6.5 and shifted the ferroelectric-relaxor transition temperature ( T F-R) down to room temperature. Thus, this process induced an ergodic relaxor phase at zero field in samples with x = 0.005. Under the electric field, the ergodic relaxor phase could reversibly transform to ferroelectric phase, which promotes the strain response with peak value of 0.38% (at 80 kV/cm, corresponding to d 33 * = 479 pm/V) at x = 0.005. Temperature-dependent measurements of both polarization and strain confirmed that the large strain originated from a reversible field-induced ergodic relaxor to ferroelectric phase transformation. The proposed material exhibits potential for nonlinear actuators.

3,5-Bis[1-acetyl-5-(4-chlorophenyl-4,5-dihydro-1H-pyrazol-3-yl]-2,6-dimethylpyridine tetrahydrofuran solvate

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Qun Qian

2008-07-01

Full Text Available In the title compound, C29H27Cl2N5O2·C4H8O, the polycyclic system is composed of three parts: one central pyridine ring substituted by two functionalized pyrazoline rings. The dihedral angles between the central pyridine plane and pyrazoline planes are 5.11 (1 and 13.99 (1°, whereas the dihedral angles between each chlorophenyl plane and the attached pyrazoline planes are 88.65 (1 and 83.87 (1°. Molecules are linked by intermolecular C—H...O hydrogen bonds, forming a three-dimensional network.

Strong red-emission of Eu{sup 3+}:Li{sub 4}Ti{sub 5}O{sub 12} powders for phosphor applications

Energy Technology Data Exchange (ETDEWEB)

Yang, Yan [Kazuo Inamori School of Engineering, New York State College of Ceramics, Alfred University, Alfred, NY 14802 (United States); Jiménez, José A. [Department of Chemistry, University of North Florida, Jacksonville, FL 32224 (United States); Wu, Yiquan, E-mail: wuy@alfred.edu [Kazuo Inamori School of Engineering, New York State College of Ceramics, Alfred University, Alfred, NY 14802 (United States)

2016-08-15

The synthesis and photoluminescence properties of trivalent europium doped lithium titanate (Eu{sup 3+}:Li{sub 4}Ti{sub 5}O{sub 12}) with different Eu{sup 3+} concentrations (0.1 mol%, 0.3 mol%, 1.0 mol%, 3.0 mol%) are reported and analyzed as a phosphor. Europium (III) nitrate (Eu(NO{sub 3}){sub 3}) was employed as Eu{sup 3+} source, while lithium acetate dihydrate (CH{sub 3}COOLi·2H{sub 2}O) and titanium n-butoxide (Ti(OC{sub 4}H{sub 9}){sub 4}) were adopted as raw materials to synthesize the host lithium titanate with a Li:Ti stoichiometry of 4.5:1. Phase identification was performed using X-ray diffraction (XRD), and morphology was examined using scanning electron microscopy (SEM). Eu{sup 3+}:Li{sub 4}Ti{sub 5}O{sub 12} powders showed strong red emission at 612 nm, corresponding to the {sup 5}D{sub 0}–{sup 7}F{sub 2} transition, with the strongest excitation peak observed in the blue light region at 464 nm. Decay time analyses revealed relatively short lifetimes accompanying typical exponential decay rates. The effect of Eu{sup 3+} concentration (0.1 mol%, 0.3 mol%, 1.0 mol%, 3.0 mol%) on photoluminescence intensity and decay time was explored, and is reported here. It was determined that the CIE color coordinates (0.66, 0.34) of the doped Li{sub 4}Ti{sub 5}O{sub 12} powders were independent of Eu{sup 3+} concentration, and that the coordinates are very similar to the ideal red chromaticity (0.67, 0.33) designated by the National Television Standard Committee (NTSC) system.

Effects of cationic substitution on the electronic and magnetic properties of manganocuprate with a layered Eu3Ba2Mn2Cu2O12 structure

International Nuclear Information System (INIS)

Matsubara, Ichiro; Funahashi, Ryoji; Ueno, Kazuo; Ishikawa, Hiroshi; Kida, Noriaki; Ohno, Nobuhito

1998-01-01

Systematic studies on the effect of substitutions on the layered manganocuprate Eu 3 Ba 2 Mn 2 Cu 2 O 12 have been conducted. To introduce holes, the authors have made substitutions of Ca for Eu and/or Sc for Mn, (Eu 3-x Ca x )Ba 2 (Mn 2-y Sc y )Cu 2 O 12 . Single-phase compounds are obtained over a fairly wide range of x and y values for x ≤ 0.7 (y = 0), x ≤ 0.5 (y = 0.5), and x ≤ 0.1 (y = 1.0). The doped holes are received predominantly at the Mn-O site and change the charge of Mn from 3+ to 4+, and no superconductivity has been obtained for any sample. The electronic ground state of (Eu 3-x Ca x )Ba 2 (Mn 2-y Sc y )Cu 2 O 12 is discussed by comparing with that of the three-dimensional perovskite La 1-x Ca x MnO 3 and K 2 NiF 4 -type La 1-x Sr 1+x MnO 4 compounds. The substitution of Sr for Ba gives rise to a different crystal structure, the Sr 3 Ti 2 O 7 structure

Zn2+, Cd2+, Hg2+ thiolates - derivatives of 2, 3, 5-trifluoro-4,6-bis(trifluoromethyl)thiophenol and heptafluoro-2-thionaphthol

International Nuclear Information System (INIS)

Larionov, S.V.; Kirichenko, V.N.; Platonov, V.E.; Maksimov, A.M.; Rodionov, P.P.; Fadeeva, V.P.; Oglezneva, I.M.; Lisojvan, V.I.; AN SSSR, Novosibirsk

1992-01-01

Zn 2+ , Cd 2+ , Hg 2+ coordination compounds with 2, 3, 5 -trifluoro- 4,6 bis(trifluoromethyl)trhiophenol (MHal) and heptafluoro-2-thionophthal (HT) of ZnHal 2 (CH 3 OH), CdHal 2 , HgHal 2 and MT 2 (M=Zn, Cd, Hg) composition, are obtained. Complexes are studied using thermal and X-ray phase analysis, vapour phase osmometry and IR spectroscopy, ZnHal 2 (CH 3 OH), CdHal 2 , ZnT 2 , HgHfl 2 , HgT 2 compounds in acetone solutions are in monomeric state, while in CdT 2 commeric particles. Frequencies of mostly valent vibrations of Cd-S bond are observed at 241 (CdHal 2 ), 225 (CdT 2 )

Mass transport in Ti0.5Sb2Te3 phase-change nanobridge

International Nuclear Information System (INIS)

Ji, Xinglong; Wu, Liangcai; Lv, Shilong; Rao, Feng; Zhu, Min; Song, Zhitang; Zhou, Xilin; Feng, Songlin

2014-01-01

Investigation of atomic migration behavior in nanoscale phase-change material is very valuable for phase-change memory applications. In this work, Ti 0.5 Sb 2 Te 3 -based phase-change nanobridges were fabricated and mass transport by atomic migration was studied. A 3-D finite-element simulation on the electrothermal field was introduced to describe the electrothermal environment in the phase-change region. During the nanosecond operation, an obvious compositional distribution resulting from atomic migration was observed in the Ti 0.5 Sb 2 Te 3 phase-change nanobridge. Based on the mass continuity equation, a physical model for mass transport is proposed to illustrate that the density variation during the amorphous-to-crystalline structural transformation is the main reason for the atomic migration in nanoscale Ti 0.5 Sb 2 Te 3 phase-change material

The OsO(3)F(+) and mu-F(OsO(3)F)(2)(+) cations: their syntheses and study by Raman and (19)F NMR spectroscopy and electron structure calculations and X-ray crystal structures of [OsO(3)F][PnF(6)] (Pn = As, Sb), [OsO(3)F][HF](2)[AsF(6)], [OsO(3)F][HF][SbF(6)], and [OsO(3)F][Sb(3)F(16)].

Science.gov (United States)

Gerken, Michael; Dixon, David A; Schrobilgen, Gary J

2002-01-28

The fluoride ion donor properties of OsO(3)F(2) have been investigated. The salts [OsO(3)F][AsF(6)], [OsO(3)F][HF](2)[AsF(6)], mu-F(OsO(3)F)(2)[AsF(6)], [OsO(3)F][HF](2)[SbF(6)], and [OsO(3)F][HF][SbF(6)] have been prepared by reaction of OsO(3)F(2) with AsF(5) and SbF(5) in HF solvent and have been characterized in the solid state by Raman spectroscopy. The single-crystal X-ray diffraction studies of [OsO(3)F][AsF(6)] (P2(1)/n, a = 7.0001(11) A, c = 8.8629(13) A, beta = 92.270(7) degrees, Z = 4, and R(1) = 0.0401 at -126 degrees C), [OsO(3)F][SbF(6)] (P2(1)/c, a = 5.4772(14) A, b = 10.115(3) A, c = 12.234(3) A, beta = 99.321(5) degrees, Z = 4, and R(1) = 0.0325 at -173 degrees C), [OsO(3)F][HF](2)[AsF(6)] (P2(1)/n, a = 5.1491(9) A, b = 8.129(2) A, c = 19.636(7) A, beta = 95.099(7) degrees, Z = 4, and R(1) = 0.0348 at -117 degrees C), and [OsO(3)F][HF][SbF(6)] (Pc, a = 5.244(4) A, b = 9.646(6) A, c = 15.269(10) A, beta = 97.154(13) degrees, Z = 4, and R(1) = 0.0558 at -133 degrees C) have shown that the OsO(3)F(+) cations exhibit strong contacts to the anions and HF solvent molecules giving rise to cyclic, dimeric structures in which the osmium atoms have coordination numbers of 6. The reaction of OsO(3)F(2) with neat SbF(5) yielded [OsO(3)F][Sb(3)F(16)], which has been characterized by (19)F NMR spectroscopy in SbF(5) and SO(2)ClF solvents and by Raman spectroscopy and single-crystal X-ray diffraction in the solid state (P4(1)m, a = 10.076(6) A, c = 7.585(8) A, Z = 2, and R(1) = 0.0858 at -113 degrees C). The weak fluoride ion basicity of the Sb(3)F(16)(-) anion resulted in an OsO(3)F(+) cation (C(3)(v) point symmetry) that is well isolated from the anion and in which the osmium is four-coordinate. The geometrical parameters and vibrational frequencies of OsO(3)F(+), ReO(3)F, mu-F(OsO(3)F)(2)(+), (FO(3)Os--FPnF(5))(2), and (FO(3)Os--(HF)(2)--FPnF(5))(2) (Pn = As, Sb) have been calculated using density functional theory methods.

Aquabis(3,5-dimethyl-1H-pyrazole-κN(oxalato-κ2O,O′copper(II

Directory of Open Access Journals (Sweden)

Andrii I. Buvailo

2008-01-01

Full Text Available In the title compound, [Cu(C2O4(C5H8N22(H2O], the CuII atom is coordinated in a slightly distorted square-pyramidal geometry by two N atoms belonging to the two 3,5-dimethyl-1H-pyrazole ligands, two O atoms of the oxalate anion providing an O,O′-chelating coordination mode, and an O atom of the water molecule occupying the apical position. The crystal packing shows a well defined layer structure. Intra-layer connections are realised through a system of hydrogen bonds while the nature of the inter-layer interactions is completely hydrophobic, including no hydrogen-bonding interactions.

(μ-3-Acetyl-5-carboxylato-4-methylpyrazolido-1:2κ4N2,O3:N1,O5-μ-chlorido-tetrapyridine-1κ2N,2κ2N-chlorido-1κCl-dicopper(II propan-2-ol solvate

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Sergey Malinkin

2009-10-01

Full Text Available The title compound, [Cu2(C7H6N2O3Cl2(C5H5N4]·C3H8O, is a binuclear pyrazolate complex, in which the two CuII atoms have different coordination numbers and are connected by a bridging Cl atom. One CuII atom has a distorted square-pyramidal coordination environment formed by two pyridine N atoms, one bridging Cl atom and an N,O-chelating pyrazolate ligand. The other CuII atom adopts an octahedral geometry defined by two pyridine N atoms at the axial positions, two Cl atoms and the coordinated pyrazolate ligand in the equatorial plane. An O—H...O hydrogen bond connects the complex molecules and propan-2-ol solvent molecules into pairs. These pairs form columns along the a axis.

Fluoride ion donor properties of cis-OsO(2)F(4): synthesis, raman spectroscopic study, and X-ray crystal structure of [OsO(2)F(3)][Sb(2)F(11)].

Science.gov (United States)

Hughes, Michael J; Mercier, Hélène P A; Schrobilgen, Gary J

2010-01-04

The salt, [OsO(2)F(3)][Sb(2)F(11)], has been synthesized by dissolution of cis-OsO(2)F(4) in liquid SbF(5), followed by removal of excess SbF(5) at 0 degrees C to yield orange, crystalline [OsO(2)F(3)][Sb(2)F(11)]. The X-ray crystal structure (-173 degrees C) consists of an OsO(2)F(3)(+) cation fluorine bridged to an Sb(2)F(11)(-) anion. The light atoms of OsO(2)F(3)(+) and the bridging fluorine atom form a distorted octahedron around osmium in which the osmium atom is displaced from its center toward an oxygen atom and away from the trans-fluorine bridge atom. As in other transition metal dioxofluorides, the oxygen ligands are cis to one another and the fluorine bridge atom is trans to an oxygen ligand and cis to the remaining oxygen ligand. The Raman spectrum (-150 degrees C) of solid [OsO(2)F(3)][Sb(2)F(11)] was assigned on the basis of the ion pair observed in the low-temperature crystal structure. Under dynamic vacuum, [OsO(2)F(3)][Sb(2)F(11)] loses SbF(5), yielding the known [mu-F(OsO(2)F(3))(2)][Sb(2)F(11)] salt with no evidence for [OsO(2)F(3)][SbF(6)] formation. Attempts to synthesize [OsO(2)F(3)][SbF(6)] by the reaction of [OsO(2)F(3)][Sb(2)F(11)] with an equimolar amount of cis-OsO(2)F(4) or by a 1:1 stoichiometric reaction of cis-OsO(2)F(4) with SbF(5) in anhydrous HF yielded only [mu-F(OsO(2)F(3))(2)][Sb(2)F(11)]. Quantum-chemical calculations at the SVWN and B3LYP levels of theory and natural bond orbital analyses were used to calculate the gas-phase geometries, vibrational frequencies, natural population analysis charges, bond orders, and valencies of OsO(2)F(3)(+), [OsO(2)F(3)][Sb(2)F(11)], [OsO(2)F(3)][SbF(6)], and Sb(2)F(11)(-). The relative thermochemical stabilities of [OsO(2)F(3)][SbF(6)], [OsO(2)F(3)][Sb(2)F(11)], [OsO(2)F(3)][AsF(6)], [mu-F(OsO(2)F(3))(2)][SbF(6)], [mu-F(OsO(2)F(3))(2)][Sb(2)F(11)], and [mu-F(OsO(2)F(3))(2)][AsF(6)] were assessed using the appropriate Born-Haber cycles to account for the preference for [mu-F(OsO(2)F(3))(2

Controlling Lateral Fano Interference Optical Force with Au-Ge2Sb2Te5 Hybrid Nanostructure

DEFF Research Database (Denmark)

Cao, Tun; Bao, Jiaxin; Mao, Libang

2016-01-01

is revealed through optical singularity in the Poynting vector. A thermal-electric simulation is adopted to investigate the temporal change of the Ge2Sb2Te5 film's temperature, which demonstrates the possibility of transiting the Ge2Sb2Te5 state by electrical heating. Our mechanism by tailoring the DQ...... in flexible nanomechanical control and may provide a new means of biomedical sensing and nano -optical conveyor belts....

N-Cyclohexyl-2-(5-fluoro-1H-indol-3-yl-2-oxoacetamide

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Dan-Li Tian

2011-07-01

Full Text Available In title compound, C16H17FN2O2, the cyclohexane ring adopts a chair conformation.. The crystal packing is stabilized by weak π–π stacking interactions [centroid–centroid distance = 3.503 (5 Å] and intermolecular C—H...O, N—H...O and N—H...F hydrogen-bond interactions.

Poly[[aqua(μ5-3,4,5,6-tetracarboxycyclohexane-1,2-dicarboxylatostrontium] monohydrate

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Pei-Chi Cheng

2011-12-01

Full Text Available In the title compound, {[Sr(C12H10O12(H2O]·H2O}n, the SrII ion is coordinated by six O atoms of five symmetry-related 3,4,5,6-tetracarboxycyclohexane-1,2-dicarboxylate ligands and one water molecule in a slightly distorted monocapped trigonal–prismatic environment. The ligands bridge the SrII ions, forming a two-dimensional structure. In the crystal, O—H...O hydrogen bonds further connect the structure into a three-dimensional network. The H atoms of two of the carboxyl groups were refined as half-occupancy.

Dicarbonyl[2-hydroxy-3,5,7-tris(morpholinomethylcyclohepta-2,4,6-trienonato(1–-κ2O1,O2]rhodium(I

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G. Steyl

2008-12-01

Full Text Available In the title compound, [Rh(C22H32N3O5(CO2], the RhI atom is coordinated by two carbonyl ligands and two tropolonate O atoms in a distorted square-planar geometry. It is an example of a new type of tropolone derivative that has not been characterized via solid-state methods. Weak intramolecular C—H...N and intermolecular C—H...O hydrogen bonds, and π–π stacking interactions between the tropolone rings [centroid–centroid distance = 3.590 (8 Å] are observed in the crystal structure.

Pd/Nb2O5/SiO2 catalyst for the direct hydrodeoxygenation of biomass-related compounds to liquid alkanes under mild conditions.

Science.gov (United States)

Shao, Yi; Xia, Qineng; Liu, Xiaohui; Lu, Guanzhong; Wang, Yanqin

2015-05-22

A simple Pd-loaded Nb2 O5 /SiO2 catalyst was prepared for the hydrodeoxygenation of biomass-related compounds to alkanes under mild conditions. Niobium oxide dispersed in silica (Nb2 O5 /SiO2 ) as the support was prepared by the sol-gel method and characterized by various techniques, including N2 adsorption, XRD, NH3 temperature-programmed desorption (TPD), TEM, and energy-dispersive X-ray spectroscopy (EDAX) atomic mapping. The characterization results showed that the niobium oxide species were amorphous and well dispersed in silica. Compared to commercial Nb2 O5 , Nb2 O5 /SiO2 has significantly more active niobium oxide species exposed on the surface. Under mild conditions (170 °C, 2.5 MPa), Pd/10 %Nb2 O5 /SiO2 was effective for the hydrodeoxygenation reactions of 4-(2-furyl)-3-buten-2-one (aldol adduct of furfural with acetone), palmitic acid, tristearin, and diphenyl ether (model compounds of microalgae oils, vegetable oils, and lignin), which gave high yields (>94 %) of alkanes with little CC bond cleavage. More importantly, owing to the significant promotion effect of NbOx species on CO bond cleavage and the mild reaction conditions, the CC cleavage was considerably restrained, and the catalyst showed an excellent activity and stability for the hydrodeoxygenation of palmitic acid with almost no decrease in hexadecane yield (94-95 %) in a 150 h time-on-stream test. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Methyl 4-(butyrylamino-5-methyl-2-nitrobenzoate

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Cheng Yao

2008-04-01

Full Text Available The title compound, C13H16N2O5, is useful as an intermediate in the field of agrochemicals. Intramolecular C—H...O hydrogen bonds result in the formation of one six- and one five-membered nearly planar ring; the six-membered ring is also nearly coplanar with the adjacent benzene ring. In the crystal structure, intermolecular C—H...O hydrogen bonds link the molecules.

A new three-dimensional cobalt phosphate: Co5(OH2)4(HPO4)2(PO4)2

International Nuclear Information System (INIS)

Han Zhangang; Tian Aixiang; Peng Jun; Zhai Xueliang

2006-01-01

A three-dimensional (3D) cobalt phosphate: Co 5 (OH 2 ) 4 (HPO 4 ) 2 (PO 4 ) 2 (1), has been synthesized by hydrothermal reaction and characterized by single-crystal X-ray diffraction, thermogravimetric analysis, and magnetic techniques. The title compound is a template free cobalt phosphate. Compound 1 exhibits a complex net architecture based on edge- and corner-sharing of CoO 6 and PO 4 polyhedra. The magnetic susceptibility measurements indicated that the title compound obeys Curie-Weiss behavior down to a temperature of 17 K at which an antiferromagnetic phase transition occurs. - Graphical abstract: A 3D cobalt phosphate with a neutral framework: Co 5 (OH 2 ) 4 (HPO 4 ) 2 (PO 4 ) 2 (1), has been synthesized and characterized. Compound 1 exhibits a complex net architecture based on edge- and corner-sharing of CoO 6 and PO 4 polyhedra. Its magnetic property was researched

Nanostructured rare earth doped Nb2O5: Structural, optical properties and their correlation with photonic applications

International Nuclear Information System (INIS)

Pereira, Rafael Ramiro; Aquino, Felipe Thomaz; Ferrier, Alban; Goldner, Philippe; Gonçalves, Rogéria R.

2016-01-01

In the present work, we report on a systematic study on structural and spectroscopic properties Eu 3+ and Er 3+ -doped Nb 2 O 5 prepared by sol–gel method. The Eu 3+ ions were used as structural probe to determine the symmetry sites occupied by lanthanide ions. The Eu 3+ -doped Nb 2 O 5 nanocrystalline powders were annealed at different temperatures to verify how the different Nb 2 O 5 crystalline phases affect the structure and the luminescence properties. Er 3+ -doped Nb 2 O 5 was prepared showing an intense NIR luminescence, and, visible luminescence on the green and red, deriving from upconversion process. The synthetized materials can find widespread applicability in photonics as red luminophor for white LED (with tricolor), optical amplifiers and upconverter materials. - Highlights: • Vis and NIR emission from nanostructured lanthanide doped Nb 2 O 5 . • Eu 3+ -doped Nb 2 O 5 as Red luminophor. • Multicolor tunability of intense upconversion emission from lanthanide doped Nb 2 O 5 . • Potential application as biological markers. • Broad band NIR emission.

Sb-SnO2-Nanosized-Based Resistive Sensors for NO2 Detection

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T. Krishnakumar

2009-01-01

Full Text Available A study over Sb-promoted tin oxide nanopowders for sensing applications is reported. SnO2 nanopowders pure and promoted with 5 wt% of antimony were prepared by wet chemical methods and widely characterized by TEM, XRD, and XPS techniques. Thick film resistive sensors were fabricated by depositing the synthesized nanopowders by drop-coating on interdigited alumina substrates. The sensing characteristics of the pure SnO2 and Sb-promoted sensors for the monitoring of trace level of NO2 were studied. The response of the sensors to water vapor was also investigated, revealing that Sb acts favorably eliminating the interference of humidity.

1-Acetyl-5-ferrocenyl-3-phenyl-2-pyrazoline

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Orhan Büyükgüngör

2009-02-01

Full Text Available In the title compound, [Fe(C5H5(C16H15N2O], the pyrazoline ring and the phenyl ring are nearly coplanar, making a dihedral angle of 6.54 (2°, while the substituted cyclopentadienyl ring is twisted out of the pyrazoline ring plane by 81.32 (1°. The molecules in the crystal structure are held together by weak C—H...O intermolecular hydrogen bonds and two C—H...π interactions.

Crystal structure of 5-hydroxy-5-propylbarbituric acid

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Thomas Gelbrich

2015-11-01

Full Text Available Molecules of the title compound, C7H10N2O4, systematic name 5-hydroxy-5-propylpyrimidine-2,4,6(1H,3H,5H-trione, form a hydrogen-bonded framework which is based on three independent hydrogen bonds, N—H...O(carbonyl, N—H...O(hydroxy and O—H...O(carbonyl. This framework has the topology of the 5-connected nov net. Each molecule is linked to five other molecules via six hydrogen bonds, and the descriptor of the hydrogen-bonded structure is F65[44.66-nov]. The crystal packing is isostructural with that of the previously reported 5-hydroxy-5-ethyl analogue.