WorldWideScience

Sample records for dysprosium selenides

  1. Synthesis and characterization of tetraphenylporphyrinate of dysprosium route dysprosium acetylacetonate

    International Nuclear Information System (INIS)

    Martinez M, V.

    1992-01-01

    Dysprosium bis (tetraphenylporphyrinate) and bis (dysprosium) Tris (tetraphenylporphyrinate) were synthesized from dysprosium tetraphenylporphyrinate prepared in situ, and characterized by IR, UV-vis, TGA, DTA, EPR and magnetic susceptibility measurements. The double decker compound was obtained by direct oxidation of the HDy(TPP) 2 intermediate. The existence of the radical anion, (TPP) - , in the double decker product was conformed by EPR spectrometry. Dysprosium monoporphyrinate was isolated and characterized by the same techniques. (Author)

  2. Formation of copper-indium-selenide and/or copper-indium-gallium-selenide films from indium selenide and copper selenide precursors

    Science.gov (United States)

    Curtis, Calvin J [Lakewood, CO; Miedaner, Alexander [Boulder, CO; Van Hest, Maikel [Lakewood, CO; Ginley, David S [Evergreen, CO; Nekuda, Jennifer A [Lakewood, CO

    2011-11-15

    Liquid-based indium selenide and copper selenide precursors, including copper-organoselenides, particulate copper selenide suspensions, copper selenide ethylene diamine in liquid solvent, nanoparticulate indium selenide suspensions, and indium selenide ethylene diamine coordination compounds in solvent, are used to form crystalline copper-indium-selenide, and/or copper indium gallium selenide films (66) on substrates (52).

  3. Precursors for formation of copper selenide, indium selenide, copper indium diselenide, and/or copper indium gallium diselenide films

    Science.gov (United States)

    Curtis, Calvin J; Miedaner, Alexander; Van Hest, Maikel; Ginley, David S

    2014-11-04

    Liquid-based precursors for formation of Copper Selenide, Indium Selenide, Copper Indium Diselenide, and/or copper Indium Galium Diselenide include copper-organoselenides, particulate copper selenide suspensions, copper selenide ethylene diamine in liquid solvent, nanoparticulate indium selenide suspensions, and indium selenide ethylene diamine coordination compounds in solvent. These liquid-based precursors can be deposited in liquid form onto substrates and treated by rapid thermal processing to form crystalline copper selenide and indium selenide films.

  4. Determination of cadmium selenide nonstoichiometry

    International Nuclear Information System (INIS)

    Brezhnev, V.Yu.; Kharif, Ya.L.; Kovtunenko, P.V.

    1986-01-01

    Physicochemical method of determination of cadmium selenide nonstoichiometry is developed. The method nature consists in the fact, that under definite conditions dissolved cadmium is extracted from crystals to a vapor phase and then is determined in it using the photocolorimetric method. Cadmium solubility in CdSe crystal is calculated from known CdSe mass and amount of separated cadmium. The lower boundary of determined contents constitutes 1x10 -5 % mol at sample of cadmium selenide 10 g

  5. On polymorphism of dysprosium trichloride

    Energy Technology Data Exchange (ETDEWEB)

    Zakiryanova, Irina D.; Khokhlov, Vladimir A.; Salyulev, Alexander B.; Korzun, Iraida V. [RAS Ural Branch, Ekaterinburg (Russian Federation). Institute of High-Temperature Electrochemistry

    2015-07-01

    For the first time, the structure of crystalline DyCl{sub 3} over a wide temperature range from room temperature to melting point was studied by Raman spectroscopy. The phonon modes (cm{sup -1}) of dysprosium trichloride (monoclinic crystal lattice of AlCl{sub 3} type, Z = 4, CN = 6) at room temperature are 257 (A{sub 1g}), 201 (E{sub g}), 112 (E{sub g}), 88 (A{sub 1g}), and 63 (E{sub g}). The monoclinic structure of the crystalline DyCl{sub 3} C{sub 2h}{sup 3} symmetry was found to remain constant over the studied temperature range. No polymorphic transformation in the solid state was detected. Gravimetry, calorimetry, and mass spectrometry have been used in addition to support the conclusions made on the basis of Raman spectroscopic data.

  6. On polymorphism of dysprosium trichloride

    International Nuclear Information System (INIS)

    Zakiryanova, Irina D.; Khokhlov, Vladimir A.; Salyulev, Alexander B.; Korzun, Iraida V.

    2015-01-01

    For the first time, the structure of crystalline DyCl 3 over a wide temperature range from room temperature to melting point was studied by Raman spectroscopy. The phonon modes (cm -1 ) of dysprosium trichloride (monoclinic crystal lattice of AlCl 3 type, Z = 4, CN = 6) at room temperature are 257 (A 1g ), 201 (E g ), 112 (E g ), 88 (A 1g ), and 63 (E g ). The monoclinic structure of the crystalline DyCl 3 C 2h 3 symmetry was found to remain constant over the studied temperature range. No polymorphic transformation in the solid state was detected. Gravimetry, calorimetry, and mass spectrometry have been used in addition to support the conclusions made on the basis of Raman spectroscopic data.

  7. Can a dysprosium shortage threaten green energy technologies?

    International Nuclear Information System (INIS)

    Hoenderdaal, Sander; Tercero Espinoza, Luis; Marscheider-Weidemann, Frank; Graus, Wina

    2013-01-01

    Dysprosium, one of the various rare earth elements, is currently for more than 99% mined in China. As China is reducing its exports, new mining projects outside of China are needed to sustain supply and meet future demands. Dysprosium is mainly used in permanent magnets to retain the magnet's strength at elevated temperatures. Therefore, the use of dysprosium doped permanent magnets is preferred in electric vehicles and direct-drive wind turbines. Based on four scenarios it could be shown that dysprosium demand will probably outstrip supply in the short term (up to 2020). Although new mines are being developed, it takes several years for them to become productive. For the long term it is expected that enough dysprosium oxide is available in the earth crust (which is economically feasible to mine with current dysprosium prices) to fulfil the projected demand of dysprosium up to 2050. Recycling of dysprosium can further secure dysprosium supply in the long term by reducing primary dysprosium use by 35% in 2050. Electric vehicles are likely to play a dominant role in future increases in dysprosium demand. Even with the limited market share in 2011, electric vehicles already contribute to 20% of dysprosium use. -- Highlights: ► Dysprosium may hamper the implementation of electric cars and wind mills. ► In the short term (up to 2020) a deficit of dysprosium supply can be expected. ► In the long term (up to 2050) sufficient dysprosium is available. ► Electric vehicles are expected to dominate future dysprosium demand. ► China's dominance in dysprosium supply is likely to decrease by 2020.

  8. Resonance ionization spectroscopy in dysprosium

    Energy Technology Data Exchange (ETDEWEB)

    Studer, D., E-mail: dstuder@uni-mainz.de; Dyrauf, P.; Naubereit, P.; Heinke, R.; Wendt, K. [Johannes Gutenberg-Universität Mainz, Institut für Physik (Germany)

    2017-11-15

    We report on resonance ionization spectroscopy (RIS) of high-lying energy levels in dysprosium. We developed efficient excitation schemes and re-determined the first ionization potential (IP) via analysis of Rydberg convergences. For this purpose both two- and three-step excitation ladders were investigated. An overall ionization efficiency of 25(4) % could be demonstrated in the RISIKO mass separator of Mainz University, using a three-step resonance ionization scheme. Moreover, an extensive analysis of the even-parity 6sns- and 6snd-Rydberg-series convergences, measured via two-step excitation was performed. To account for strong perturbations in the observed s-series, the approach of multichannel quantum defect theory (MQDT) was applied. Considering all individual series limits we extracted an IP-value of 47901.76(5) cm{sup −1}, which agrees with the current literature value of 47901.7(6) cm{sup −1}, but is one order of magnitude more precise.

  9. Nature of the magnetic susceptibility of dysprosium. Paramagnetic susceptibility of dysprosium - yttrium alloys

    International Nuclear Information System (INIS)

    Demidov, V.G.; Levitin, R.Z.; Chistyakov, O.D.

    1976-01-01

    The paramagnetic susceptibility of single crystals of dysprosium-yttirum alloys is measured in the basal plane and along the hexagonal axis. It is shown that the susceptibility of the alloys obeys the Curie-Weiss law, the effective magnetic moments allong the different directions being the same and the paramagnetic Curie temperatures being different. The difference between the paramagnetic Curie temperatures in the basal plane and along the hexagonal axis is independent of the dysprosium concentration in the alloy. As a comparison with the theoretical models of magnetic anisotropy shows, this is an indication that the magnetic anisotropy of dysprosium - yttrium alloys is of a single-ion nature

  10. Semiconductor composition containing iron, dysprosium, and terbium

    Science.gov (United States)

    Pooser, Raphael C.; Lawrie, Benjamin J.; Baddorf, Arthur P.; Malasi, Abhinav; Taz, Humaira; Farah, Annettee E.; Kalyanaraman, Ramakrishnan; Duscher, Gerd Josef Mansfred; Patel, Maulik K.

    2017-09-26

    An amorphous semiconductor composition includes 1 to 70 atomic percent iron, 15 to 65 atomic percent dysprosium, 15 to 35 atomic percent terbium, balance X, wherein X is at least one of an oxidizing element and a reducing element. The composition has an essentially amorphous microstructure, an optical transmittance of at least 50% in at least the visible spectrum and semiconductor electrical properties.

  11. Dysprosium complexes with the tetraphenylporphyrin macrocyclic ligand

    International Nuclear Information System (INIS)

    Martinez M, V.; Padilla, J.; Ramirez, F.M.

    1992-04-01

    In this report, the results obtained on the synthesis, characterization and study of the chemical behavior of dysprosium complex with the acetylacetone chelating agent (Hacac) and the tetraphenylporphyrin macrocyclic ligand (H 2 TFP) are given. Based on the literature but according to our necessities and interest, the appropriate methodology settled down from the synthesis of prime matters until the obtaining and characterization of the products. The acetyl acetonate complex was obtained of mono hydrated dysprosium [Dy(acac) 3 . H 2 0] and trihydrated [Dy(acac) 3 .3 H 2 0], the mono tetra phenyl porphyrinate [Dy(TFP)(acac). 2 ac] the double sandwich of the dysprosium porphyrinate [Dy(TFP) 2 ] and the triple sandwich of the dysprosium porphyrinate [Dy(TFP) 3 . 2 TCB] (TCB = trichlorobenzene). Its were characterized by their melting points, solubility, IR, UV, TGA and DTA both first and besides the techniques already mentioned for NMR'H, RPE and Magnetic susceptibility the three last complexes. From the spectroscopic point of view, IR and RPE its suggested the existence of a complex of inverse mixed valence [Dy(TFP) 2- (TFP) 1- ] for the Dy(TFP) 2 as a result of the existence of the free radical (TFP' 1- and that it was not in none of the other porphyrin compounds. In the NMR'H spectra of the compounds were not observed signals in the region from 0 to 10 ppm that which shows that the dysprosium complexes in special those of the porphyrin type are highly paramagnetic and its could be used as displacement reagents, creators of images and contrast agents of great utility in these days in studies of NMR, technique today by today used in medical diagnoses. (Author)

  12. Heat capacity measurements on dysprosium titanate

    International Nuclear Information System (INIS)

    Kandan, R.; Prabhakara Reddy, B.; Panneerselvam, G.; Nagarajan, K.

    2014-01-01

    Dysprosium titanate is considered as a candidate material for use in the control rods of future nuclear reactors. The Dy 2 TiO 5 compound was prepared by solid-state synthesis and characterized by XRD technique. The high temperature enthalpy increments of dysprosium titanates have been measured for the first time by employing the method of inverse drop calorimetry in the temperature range 748-1645 K by using high temperature drop calorimeter. The calorimeter, the method of measurement and the procedure adopted for enthalpy increment measurements and analysis of the measured data to compute thermodynamic functions have been described elsewhere. The measured enthalpy increments were fitted to polynomial in temperature by using the least squares method. The fit equation in the temperature range from 298 to 1800 K is given

  13. High temperature oxidation kinetics of dysprosium particles

    Energy Technology Data Exchange (ETDEWEB)

    Jaques, Brian J.; Butt, Darryl P., E-mail: DarrylButt@BoiseState.edu

    2015-09-25

    Highlights: • The oxidation behavior of dysprosium particles was studied from 500 to 1000 °C. • Activation energy in initial region found as 8–25 kJ/mol, depending on atmosphere. • Activation energy in intermediate region found as 80–95 kJ/mol. • The oxide grows at the metal–oxide interface. • Generally, the formed oxide behaved as a p-type semiconductor. - Abstract: Rare earth elements have been recognized as critical materials for the advancement of many strategic and green technologies. Recently, the United States Department of Energy has invested many millions of dollars to enhance, protect, and forecast their production and management. The work presented here attempts to clarify the limited and contradictory literature on the oxidation behavior of the rare earth metal, dysprosium. Dysprosium particles were isothermally oxidized from 500 to 1000 °C in N{sub 2}–(2%, 20%, and 50%) O{sub 2} and Ar–20% O{sub 2} using simultaneous thermal analysis techniques. Two distinct oxidation regions were identified at each isothermal temperature in each oxidizing atmosphere. Initially, the oxidation kinetics are very fast until the reaction enters a slower, intermediate region of oxidation. The two regions are defined and the kinetics of each are assessed to show an apparent activation energy of 8–25 kJ/mol in the initial region and 80–95 kJ/mol in the intermediate oxidation reaction region. The effects of varying the oxygen partial pressure on the reaction rate constant are used to show that dysprosium oxide (Dy{sub 2}O{sub 3}) generally acts as a p-type semiconductor in both regions of oxidation (with an exception above 750 °C in the intermediate region)

  14. Can a dysprosium shortage threaten green energy technologies?

    NARCIS (Netherlands)

    Hoenderdaal, S.; Tercero Espinoza, L.; Marschneider-Weidemann, F.; Crijns - Graus, Wina|info:eu-repo/dai/nl/308005015

    2013-01-01

    Dysprosium, one of the various rare earth elements, is currently for more than 99% mined in China. As China is reducing its exports, new mining projects outside of China are needed to sustain supply and meet future demands. Dysprosium is mainly used in permanent magnets to retain the magnet's

  15. Ethanolamine derivatives of dysprosium and holmium

    International Nuclear Information System (INIS)

    Gharia, K.S.; Singh, M.; Mathur, S.; Sankhla, B.S.

    1981-01-01

    The preparation and properties of dysprosium and holmium derivatives of mono-, di- and tri-ethanolamine derivatives are described. Compounds of general formulae: Ln(OPrsup(i)) 2 (mea), Ln(OPrsup(i))(mea) 2 , Ln(mea) 3 , Ln(OPrsup(i))(dea), Ln 2 (dea) 3 , Ln(dea)(deaH) and Ln(tea) (where Ln = Dy or Ho and mea, dea and tea are the anions of respective ethanolamine) were obtained and characterized by elemental analysis and IR spectra. (author)

  16. Synthesis and characterization of tetraphenylporphyrinate of dysprosium route dysprosium acetylacetonate.; Sintesis y caracterizacion de un porfirinato de disprosio via acetilacetonato de disprosio.

    Energy Technology Data Exchange (ETDEWEB)

    Martinez M, V

    1993-12-31

    Dysprosium bis (tetraphenylporphyrinate) and bis (dysprosium) Tris (tetraphenylporphyrinate) were synthesized from dysprosium tetraphenylporphyrinate prepared in situ, and characterized by IR, UV-vis, TGA, DTA, EPR and magnetic susceptibility measurements. The double decker compound was obtained by direct oxidation of the HDy(TPP){sub 2} intermediate. The existence of the radical anion, (TPP){sup -} , in the double decker product was conformed by EPR spectrometry. Dysprosium monoporphyrinate was isolated and characterized by the same techniques. (Author).

  17. Method for producing dysprosium-iron-boron alloy powder

    International Nuclear Information System (INIS)

    Camp, F.E.; Wooden, S.A.

    1989-01-01

    A method for producing a dysprosium-iron alloy adapted for use in the manufacture of rare-earth element containing, iron-boron permanent magnets, the method including providing a particle mixture comprising dysprosium oxide, iron and calcium, compacting the particle mixture to produce a consolidated article, heating the article for a time at temperature to form a metallic compound comprising dysprosium and iron and to form calcium oxide, producing a particle mass of -35 mesh from the compact, washing the particle mass with water at a temperature no greater than 10 0 C to react to the calcium and to the calcium oxide therewith to form a calcium hydroxide, while preventing oxidation of the particle mass, and removing the calcium hydroxide from the particle mass

  18. Characterization of tin selenides synthesized by high-energy milling

    Directory of Open Access Journals (Sweden)

    Marcela Achimovičová

    2011-12-01

    Full Text Available Tin selenides SnSeX (x=1,2 were synthesized from tin and selenium powder precursors by high-energy milling in the planetary ballmill Pulverisette 6 (Fritsch, Germany. The orthorhombic tin selenide SnSe and the hexagonal tin diselenide SnSe2 phases were formed after4 min and 5 min of milling, respectively. Specific surface area of both selenides increased with increasing time of mechanochemicalsynthesis. The particle size distribution analysis demonstrated that the synthesized products contain agglomerated selenide particlesconsisting of numerous idiomorphic tin selenide crystals, measuring from 2 to more than 100 nm in diameter, which were also documentedby TEM. UV-Vis spectrophotometry confirmed that tin selenide particles do not behave as quantum dots.

  19. Selenide isotope generator for the Galileo mission

    International Nuclear Information System (INIS)

    Goebel, C.J.; Hammel, T.E.

    1978-01-01

    A significantly improved thermoelectric generator has been developed to provide electric power for NASA's Galileo Mission in 1982. Nominal power requirements for Galileo will be about 450 watts at BOL (Beginning of Life), and this will be furnished by two Selenide Isotope Generators (SIG) each powered by a Multi Hundred Watt (MHW) radioisotopic heat source. A Ground Demonstration System (GDS) of a nominal 100 w(e) features a 3M - produced selenide ring module around a shortened MHW-dimensioned electrical heat source, newly developed axially-grooved heat pipes on a disc-shaped radiator, and other innovations which will allow a full-sized generator's weight to be held at about 90 lbs

  20. Fabrication, characterization and applications of iron selenide

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, Raja Azadar, E-mail: hussainazadar@yahoo.com [Department of Chemistry, Quaid-i-Azam University, 45320 Islamabad (Pakistan); Badshah, Amin [Department of Chemistry, Quaid-i-Azam University, 45320 Islamabad (Pakistan); Lal, Bhajan [Department of Energy Systems Engineering, Sukkur Institute of Business Administration (Pakistan)

    2016-11-15

    This review article presents fabrication of FeSe by solid state reactions, solution chemistry routes, chemical vapor deposition, spray pyrolysis and chemical vapor transport. Different properties and applications such as crystal structure and phase transition, band structure, spectroscopy, superconductivity, photocatalytic activity, electrochemical sensing, and fuel cell activity of FeSe have been discussed. - Graphical abstract: Iron selenide can be synthesized by solid state reactions, chemical vapor deposition, solution chemistry routes, chemical vapor transport and spray pyrolysis. - Highlights: • Different fabrication methods of iron selenide (FeSe) have been reviewed. • Crystal structure, band structure and spectroscopy of FeSe have been discussed. • Superconducting, catalytic and fuel cell application of FeSe have been presented.

  1. Cybernetic prediction of selenide Chevreul's phases

    International Nuclear Information System (INIS)

    Kiseleva, N.N.; Savitskij, E.M.

    1981-01-01

    The method of training a computer is used to forecast the possibility for the formation of selenide Chevreul's phases of the Asub(x)Bsub(6)Sesub(8) composition (where A is any chemical element, B-Mo, Cr, W, Re). The peculiarities of applying cybernetic forecasting systems in inorganic chemistry are considered. The critical temperature of transfer into the superconducting state of some phases forecasted is estimated [ru

  2. Synthesis and thermal decomposition study of dysprosium trifluoroacetate

    DEFF Research Database (Denmark)

    Opata, Y. A.; Grivel, J.-C.

    2018-01-01

    A study of the thermal decomposition process of dysprosium trifluoroacetate hydrate under flowing argon is presented. Thermogravimetry, differential thermal analysis, evolved gas analysis and ex-situ x-ray diffraction techniques have been employed in the investigation. Three main stages were...

  3. Magnon contribution to electrical resistance of gadolinium-dysprosium alloy single crystals

    International Nuclear Information System (INIS)

    Nikitin, S.A.; Slobodchikov, S.S.; Solomkin, I.K.

    1978-01-01

    The magnon, phonon and interelectron collision contributions to the electric resistance of single crystals of gadolinium-dysprosium alloys were quantified. A relationship was found to exist between the electric resistance and the variation of the topology of the Fermi surface on melting of gadolinium with dysprosium. It was found that gadolinium-dysprosium alloys, which have no helicoidal magnetic structure in magnetically ordered state, feature a spin-spin helicoidal-type correlations in the paramagnetic field

  4. Compounds of divalent thulium, neodymium, and dysprosium

    International Nuclear Information System (INIS)

    Bochkarev, M.N.; Fedushkin, I.L.; Trifonov, A.A.; Fagin, A.A.; Kirillov, E.N.

    1998-01-01

    Full text: Judging on the Ln(II)/Ln(III) potentials Tm, Nd, and Dy are the first candidates after Sm, Eu, and Yb for the preparation of Ln(II) compounds. The first molecular Tm(II) derivatives, TmI 2 (DME) 3 (I), has been obtained recently by the reduction of TmI 3 with thulium metal in DME (1,2-dimethoxyethane). The tetrahydrofuran (THF) analogue, TmI 2 (THF) 5 , was synthesized similarly. In the case of TmBI 3 and TmCl 3 the same reaction does not occur. The compound I is inert toward naphthalene, anthracene, phenylacetylene, CpH, (Me 3 Si) 2 NH, 2,4,6-t-Bu 3 C 6 H 2 OH, Cp 2 V, Cp 2 Fe, or Cp 3 Er. The reactions of I with PhOH, Ph 3 COH, 3,6-t-Bu 2 C 6 H 2 (OH) 2 -1,2 (Cat), and calixarene (Cal) produce, Ph 3 COTmI 2 (DME) 2 , (Cat)TmI(DME) 2 , and (Cal)TmI, correspondingly. The attempts to use I for preparation of the other Tm(II) complexes failed. In all cases (reactions with C 10 H 8 Li, CpK, [1,3-(Me 3 Si) 2 C 5 H 3 ]MgCl, and [Cp'-SiMe 2 -Ind']K 2 ) the Tm(III) derivatives (respectively, (C 10 H 8 Tm) 2 C 10 H 8 , Cp 3 Tm, [1,3-(Me 3 Si) 2 C 5 H 3 ] 2 TmCl, and Cp'-SiMe 2 -Ind')TmI) were obtained. The new stable Tm(II) complex, PhOTmI(DME) 2 (II), has been synthesized by the reduction of I with potassium metal in DME. The product was isolated as the green crystals with μ eff 4.6 BM. Unlike TmI 3 , NdI 3 and DyI 3 can not be reduced by metallic neodymium, dysprosium or sodium in DME or THF. Re-investigation of the product formed in the reaction of NdCl 3 with a lack of Li and naphthalene which was claimed before as NdCl 2 (THF) 2 has shown that this is a mixture of Nd(III) naphthalene complexes of the type [(NdCl 2 (THF) 2 ]nC 10 H 8 (n = 4- 7) (III). Nevertheless the product may be used instead of NdCl 2 for the preparation of RNdCl 2 type complexes. The reactions of III with t-BuNCH=CHNBu-t (DAD), PhCH=CHCH=CHPh (DBD), and PhCH=CHPh afford (DAD)NdCl 2 (THF) 2 , (DBD)[NdCl 2 (THF) 2 ] 2 , and (PhCHCHPh)[NdCl 2 ] 2 (THF) 3 , respectively. The iodides of Nd

  5. Properties of Polydisperse Tin-doped Dysprosium and Indium Oxides

    Directory of Open Access Journals (Sweden)

    Malinovskaya Tatyana

    2017-01-01

    Full Text Available The results of investigations of the complex permittivity, diffuse-reflectance, and characteristics of crystal lattices of tin-doped indium and dysprosium oxides are presented. Using the methods of spectroscopy and X-ray diffraction analysis, it is shown that doping of indium oxide with tin results in a significant increase of the components of the indium oxide complex permittivity and an appearance of the plasma resonance in its diffuse-reflectance spectra. This indicates the appearance of charge carriers with the concentration of more than 1021 cm−3 in the materials. On the other hand, doping of the dysprosium oxide with the same amount of tin has no effect on its optical and electromagnetic properties.

  6. Charge transfer cross sections for dysprosium and cerium

    Energy Technology Data Exchange (ETDEWEB)

    Adachi, Hajime; Tamura, Koji; Okazaki, Tetsuji; Shibata, Takemasa [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-06-01

    Symmetric resonant charge transfer cross sections between singly ionized ions and the parent atoms were measured for dysprosium and cerium in the impact energy of 200-2000eV. The cross sections were determined from the ratio between the number of ions produced by charge transfer and those in primary ion beam. The primary ion beam was produced by a laser ion source in which their atoms were ionized by laser resonant photo-ionization. The slow ions produced by charge transfer and fast primary ions were detected with Faraday cups. The obtained cross sections were (1.82{+-}0.14) x 10{sup -14} cm{sup 2} for dysprosium and (0.88{+-}0.12) x 10{sup -14} cm{sup 2} for cerium in the above energy range. The difference of these values can mostly be explained by considering the electron configurations of these atoms and ions. (author)

  7. Charge transfer cross sections for dysprosium and cerium

    International Nuclear Information System (INIS)

    Adachi, Hajime; Tamura, Koji; Okazaki, Tetsuji; Shibata, Takemasa

    1998-06-01

    Symmetric resonant charge transfer cross sections between singly ionized ions and the parent atoms were measured for dysprosium and cerium in the impact energy of 200-2000eV. The cross sections were determined from the ratio between the number of ions produced by charge transfer and those in primary ion beam. The primary ion beam was produced by a laser ion source in which their atoms were ionized by laser resonant photo-ionization. The slow ions produced by charge transfer and fast primary ions were detected with Faraday cups. The obtained cross sections were (1.82±0.14) x 10 -14 cm 2 for dysprosium and (0.88±0.12) x 10 -14 cm 2 for cerium in the above energy range. The difference of these values can mostly be explained by considering the electron configurations of these atoms and ions. (author)

  8. Neutron capture measurements and resonance parameters of dysprosium

    Energy Technology Data Exchange (ETDEWEB)

    Shin, S.G.; Kye, Y.U.; Namkung, W.; Cho, M.H. [Pohang University of Science and Technology, Division of Advanced Nuclear Engineering, Pohang, Gyeongbuk (Korea, Republic of); Kang, Y.R.; Lee, M.W. [Dongnam Inst. of Radiological and Medical Sciences, Research Center, Busan (Korea, Republic of); Kim, G.N. [Kyungpook National University, Department of Physics, Daegu (Korea, Republic of); Ro, T.I. [Dong-A University, Department of Physics, Busan (Korea, Republic of); Danon, Y.; Williams, D. [Rensselaer Polytechnic Institute, Department of Mechanical, Aerospace, and Nuclear Engineering, Troy, NY (United States); Leinweber, G.; Block, R.C.; Barry, D.P.; Rapp, M.J. [Naval Nuclear Laboratory, Knolls Atomic Power Laboratory, Schenectady, NY (United States)

    2017-10-15

    Neutron capture yields of dysprosium isotopes ({sup 161}Dy, {sup 162}Dy, {sup 163}Dy, and {sup 164}Dy) were measured using the time-of-flight method with a 16 segment sodium iodide multiplicity detector. The measurements were made at the 25m flight station at the Gaerttner LINAC Center at Rensselaer Polytechnic Institute. Resonance parameters were obtained using the multilevel R-matrix Bayesian code SAMMY. The neutron capture data for four enriched dysprosium isotopes and one natural dysprosium sample were sequentially fitted. New resonances not listed in ENDF/B-VII.1 were observed. There were 29 and 17 new resonances from {sup 161}Dy and {sup 163}Dy isotopes, respectively. Six resonances from {sup 161}Dy isotope, two resonances from {sup 163}Dy, and four resonances from {sup 164}Dy were not observed. The capture resonance integrals of each isotope were calculated with the resulting resonance parameters and those of ENDF/B-VII.1 in the energy region from 0.5 eV to 20 MeV and were compared to the capture resonance integrals with the resonance parameters from ENDF/B-VII.1. A resonance integral value of the natural dysprosium calculated with present resonance parameters was 1405 ± 3.5 barn. The value is ∝ 0.3% higher than that obtained with the ENDF/B-VII.1 parameters. The distributions of the present and ENDF/B-VII.1 neutron widths were compared to a Porter-Thomas distribution. Neutron strength functions for {sup 161}Dy and {sup 163}Dy were calculated with the present resonance parameters and both values were in between the values of ''Atlas of Neutron Resonances'' and ENDF/B-VII.1. The present radiation width distributions of {sup 161}Dy and {sup 163}Dy were fitted with the χ{sup 2} distribution by varying the degrees of freedom. (orig.)

  9. The development of dysprosium-165 hydroxide macroaggregates for radiation synovectomy

    International Nuclear Information System (INIS)

    McLaren, A.B.; Hetherington, E.L.R.; Maddalena, D.J.; Snowden, G.M.

    1988-06-01

    The development of a dysprosium-165 product, Dy-HMA, which is suitable for the radiation synovectomy of arthritic joints is described. Dysprosium-165 is a short-lived (t 1/2 = 139 min) beta-emitter produced by the neutron irradiation of natural dysprosium. Dy-HMA is a suspension of macroaggregated hydroxide particles in saline with the majority of particles in the 3-5 μm range. Studies in rabbits have demonstrated minimal leakage following the intra-articular injection of a knee joint. At 24 hours, the accumulation in the liver is about 0.003% of the injected dose and there is considerably less in other organs and tissue. The use of Dy-HMA has considerable advantages over the presently used yttrium-90 products. The undesired leakage to and subsequent irradiation of other organs is considerably reduced. The period of hospitalisation is reduced from four days to one and the production of 165 Dy in Australia will overcome the difficulties of supply 90 Y from overseas. 21 refs., 1 fig., 18 tabs

  10. Dosimetric properties of dysprosium doped lithium borate glass irradiated by 6 MV photons

    International Nuclear Information System (INIS)

    Ab Rasid, A.; Wagiran, H.; Hashim, S.; Ibrahim, Z.; Ali, H.

    2015-01-01

    Undoped and dysprosium doped lithium borate glass system with empirical formula (70–x) B 2 O 3 –30 Li 2 O–(x) Dy 2 O 3 (x=0.1, 0.3, 0.5, 0.7, 1.0 mol%) were prepared using the melt-quenching technique. The dosimetric measurements were performed by irradiating the samples to 6 MV photon beam using linear accelerator (LINAC) over a dose range of 0.5–5.0 Gy. The glass series of dysprosium doped lithium borate glass produced the best thermoluminescence (TL) glow curve with the highest intensity peak from sample with 1.0 mol% Dy 2 O 3 concentration. Minimum detectable dose was detected at 2.24 mGy, good linearity of regression coefficient, high reproducibility and high sensitivity compared to the undoped glass are from 1.0 mol% dysprosium doped lithium borate glass. The results indicated that the series of dysprosium doped lithium glasses have a great potential to be considered as a thermoluminescence dosimetry (TLD). - Highlights: • TL response of undoped and dysprosium doped lithium borate glass subjected to 6 MV photons irradiation at low dose range. • TL linear response of dysprosium doped lithium borate glass. • The sensitivity of dysprosium doped lithium borate glass is approximately 93 times higher than undoped glass

  11. Neutralization by metal ions of the toxicity of sodium selenide.

    Directory of Open Access Journals (Sweden)

    Marc Dauplais

    Full Text Available Inert metal-selenide colloids are found in animals. They are believed to afford cross-protection against the toxicities of both metals and selenocompounds. Here, the toxicities of metal salt and sodium selenide mixtures were systematically studied using the death rate of Saccharomyces cerevisiae cells as an indicator. In parallel, the abilities of these mixtures to produce colloids were assessed. Studied metal cations could be classified in three groups: (i metal ions that protect cells against selenium toxicity and form insoluble colloids with selenide (Ag⁺, Cd²⁺, Cu²⁺, Hg²⁺, Pb²⁺ and Zn²⁺, (ii metal ions which protect cells by producing insoluble metal-selenide complexes and by catalyzing hydrogen selenide oxidation in the presence of dioxygen (Co²⁺ and Ni²⁺ and, finally, (iii metal ions which do not afford protection and do not interact (Ca²⁺, Mg²⁺, Mn²⁺ or weakly interact (Fe²⁺ with selenide under the assayed conditions. When occurring, the insoluble complexes formed from divalent metal ions and selenide contained equimolar amounts of metal and selenium atoms. With the monovalent silver ion, the complex contained two silver atoms per selenium atom. Next, because selenides are compounds prone to oxidation, the stabilities of the above colloids were evaluated under oxidizing conditions. 5,5'-dithiobis-(2-nitrobenzoic acid (DTNB, the reduction of which can be optically followed, was used to promote selenide oxidation. Complexes with cadmium, copper, lead, mercury or silver resisted dissolution by DTNB treatment over several hours. With nickel and cobalt, partial oxidation by DTNB occurred. On the other hand, when starting from ZnSe or FeSe complexes, full decompositions were obtained within a few tens of minutes. The above properties possibly explain why ZnSe and FeSe nanoparticles were not detected in animals exposed to selenocompounds.

  12. Elevated temperature study of Nd-Fe-B--based magnets with cobalt and dysprosium additions

    International Nuclear Information System (INIS)

    Gauder, D.R.; Froning, M.H.; White, R.J.; Ray, A.E.

    1988-01-01

    This paper discusses the elevated temperature performance of Nd-Fe-B magnets containing 0--15 wt. % cobalt substitutions for iron and 0--10 wt. % dysprosium substitutions for neodymium. Test samples were prepared using conventional powder metallurgy techniques. Elevated temperature hysteresis loop and open-circuit measurements were performed on the samples to investigate irreversible losses and long term aging losses at 150 0 C. Magnets with high amounts of both cobalt and dysprosium exhibited lower losses of coercivity and magnetization. Dysprosium had more influence on the elevated temperature performance of the material than did cobalt

  13. Ex situ formation of metal selenide quantum dots using bacterially derived selenide precursors

    International Nuclear Information System (INIS)

    Fellowes, J W; Pattrick, R A D; Lloyd, J R; Charnock, J M; Coker, V S; Mosselmans, J F W; Weng, T-C; Pearce, C I

    2013-01-01

    Luminescent quantum dots were synthesized using bacterially derived selenide (Se II− ) as the precursor. Biogenic Se II− was produced by the reduction of Se IV by Veillonella atypica and compared directly against borohydride-reduced Se IV for the production of glutathione-stabilized CdSe and β-mercaptoethanol-stabilized ZnSe nanoparticles by aqueous synthesis. Biological Se II− formed smaller, narrower size distributed QDs under the same conditions. The growth kinetics of biologically sourced CdSe phases were slower. The proteins isolated from filter sterilized biogenic Se II− included a methylmalonyl-CoA decarboxylase previously characterized in the closely related Veillonella parvula. XAS analysis of the glutathione-capped CdSe at the S K-edge suggested that sulfur from the glutathione was structurally incorporated within the CdSe. A novel synchrotron based XAS technique was also developed to follow the nucleation of biological and inorganic selenide phases, and showed that biogenic Se II− is more stable and more resistant to beam-induced oxidative damage than its inorganic counterpart. The bacterial production of quantum dot precursors offers an alternative, ‘green’ synthesis technique that negates the requirement of expensive, toxic chemicals and suggests a possible link to the exploitation of selenium contaminated waste streams. (paper)

  14. Ex Situ Formation of Metal Selenide Quantum Dots Using Bacterially Derived Selenide Precursors

    Energy Technology Data Exchange (ETDEWEB)

    Fellowes, Jonathan W.; Pattrick, Richard; Lloyd, Jon; Charnock, John M.; Coker, Victoria S.; Mosselmans, JFW; Weng, Tsu-Chien; Pearce, Carolyn I.

    2013-04-12

    Luminescent quantum dots were synthesized using bacterially derived selenide (SeII-) as the precursor. Biogenic SeII- was produced by the reduction of Se-IV by Veillonella atypica and compared directly against borohydride-reduced Se-IV for the production of glutathione-stabilized CdSe and beta-mercaptoethanol-stabilized ZnSe nanoparticles by aqueous synthesis. Biological SeII- formed smaller, narrower size distributed QDs under the same conditions. The growth kinetics of biologically sourced CdSe phases were slower. The proteins isolated from filter sterilized biogenic SeII- included a methylmalonyl-CoA decarboxylase previously characterized in the closely related Veillonella parvula. XAS analysis of the glutathione-capped CdSe at the S K-edge suggested that sulfur from the glutathione was structurally incorporated within the CdSe. A novel synchrotron based XAS technique was also developed to follow the nucleation of biological and inorganic selenide phases, and showed that biogenic SeII- is more stable and more resistant to beam-induced oxidative damage than its inorganic counterpart. The bacterial production of quantum dot precursors offers an alternative, 'green' synthesis technique that negates the requirement of expensive, toxic chemicals and suggests a possible link to the exploitation of selenium contaminated waste streams.

  15. Slow recombination centers in cadmium selenide monocrystalline films

    International Nuclear Information System (INIS)

    Smyntyna, V.A.

    1983-01-01

    As a result of annealing when concentration of selenium Vacancies decreases due to their diffusion towards the surface, show recombination K-centers begin to influence the photoelectric properties of monocrystalline cadmium selenide layers. Energy levels of K-centers are located by 0.23-0.25 eV over the valent zone ceiling. The nature of K-centers is determined by the presence in the cadmium selenide layer structure of intrisic defects-cadmium vacancies in contrast to r-centers of slow recombination which are bound with impurities in a semiconductor material

  16. Study on the electrochemical of the metal deposition from ionic liquids for lithium, titanium and dysprosium

    International Nuclear Information System (INIS)

    Berger, Claudia A.

    2017-01-01

    The thesis was aimed to the characterization of electrochemically deposited film of lithium, titanium and dysprosium on Au(111) from different ionic liquids, finally dysprosium on neodymium-iron-boron magnate for industrial applications. The investigation of the deposits were performed using cyclic voltametry, in-situ scanning tunneling microscopy, electrochemical quartz microbalance, XPS and Auger electron spectroscopy. The sample preparation is described in detail. The deposition rate showed a significant temperature dependence.

  17. A terminal fluoride ligand generates axial magnetic anisotropy in dysprosium complexes

    Energy Technology Data Exchange (ETDEWEB)

    Norel, Lucie [Department of Chemistry, University of California, Berkeley, CA (United States); Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, Rennes (France); Darago, Lucy E.; Chakarawet, Khetpakorn; Gonzalez, Miguel I.; Olshansky, Jacob H.; Long, Jeffrey R. [Department of Chemistry, University of California, Berkeley, CA (United States); Le Guennic, Boris; Rigaut, Stephane [Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, Rennes (France)

    2018-02-12

    The first dysprosium complexes with a terminal fluoride ligand are obtained as air-stable compounds. The strong, highly electrostatic dysprosium-fluoride bond generates a large axial crystal-field splitting of the J=15/2 ground state, as evidenced by high-resolution luminescence spectroscopy and correlated with the single-molecule magnet behavior through experimental magnetic susceptibility data and ab initio calculations. (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Terbium and dysprosium complexes luminescence at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Meshkova, S B; Kravchenko, T B; Kononenko, L.I.; Poluehktov, N S [AN Ukrainskoj SSR, Odessa. Fiziko-Khimicheskij Inst.

    1979-01-01

    The variation is studied of the luminescence intensity of terbium and dysprosium complexes used in the analysis as solutions are cooled down to the liquid nitrogen temperature. Three groups of methods have been studied: observation of fluorescence of aqueous solutions, precipitate and extract suspensions in organic solvents. The brightest luminescence and greatest increase in luminescence intensity are observed at freezing of complex solvents with 1,2-dioxybenzene-3,5-disulfonic acid (DBSA) and iminodiacetic acid (IDA) and DBSA+EDTA, as well as in the case of benzene extracting of complexes with phenanthroline and salicylic acid. Otherwise the intensity increases 2-14-fold and for the complex of terbium with acetoacetic ester 36-fold.

  19. Dysprosium (holmium) determination in the presence of erbium and dysprosium (holmium, erbium) determination in the presence of cerium

    International Nuclear Information System (INIS)

    Tolubara, A.I.; Kochubej, A.I.; Usatenko, Yu.I.

    1978-01-01

    Effect of salicylic acid upon complex formation in the systems REE - boronsulfoalizarinate, REE - oxine and REE - boronsulfoalizarinate - oxine is investigated. Comparison of optical characteristics of the above systems in the absence and in the presence of salicylic acid is carried out. It is established that in all the cases the effect of salicylic acid depends both on the nature of REE and the ratio of all the components of the system. Under certain conditions the given dependence is observed only for erbium complexes. Extraction-photometric methods of dysprosium and holmium determination in the presence of equal erbium amounts, as well as holmium and erbium determination in the presence of cerium equal amounts is developed

  20. Dysprosium (holmium) determination in the presence of erbium and dysprosium (holmium, erbium) determination in the presence of cerium

    Energy Technology Data Exchange (ETDEWEB)

    Tolubara, A I; Kochubei, A I; Usatenko, Yu I

    1978-01-01

    Effect of salicylic acid upon complex formation in the systems REE - boronsulfoalizarinate, REE - oxine and REE - boronsulfoalizarinate - oxine is investigated. Comparison of optical characteristics of the above systems in the absence and in the presence of salicylic acid is carried out. It is established that in all the cases the effect of salicylic acid depends both on the nature of REE and the ratio of all the components of the system. Under certain conditions the given dependence is observed only for erbium complexes. Extraction-photometric methods of dysprosium and holmium determination in the presence of equal erbium amounts, as well as holmium and erbium determination in the presence of cerium equal amounts is developed.

  1. Mechanochemical synthesis of nanocrystalline lead selenide. Industrial approach

    Energy Technology Data Exchange (ETDEWEB)

    Achimovicova, Marcela; Balaz, Peter [Slovak Academy of Sciences, Kosice (Slovakia). Inst. of Geotechnics; Durisin, Juraj [Slovak Academy of Sciences, Kosice (Slovakia). Inst. of Materials Research; Daneu, Nina [Josef Stefan Institute, Ljubljana (Slovenia). Dept. for Nanostructured Materials; Kovac, Juraj; Satka, Alexander [Slovak Univ. of Technology and International Laser Centre, Bratislava (Slovakia). Dept. of Microelectronics; Feldhoff, Armin [Leibniz Univ. Hannover (Germany). Inst. fuer Physikalische Chemie und Elektrochemie; Gock, Eberhard [Technical Univ. Clausthal, Clausthal-Zellerfeld (Germany). Inst. of Mineral and Waste Processing and Dumping Technology

    2011-04-15

    Mechanochemical synthesis of lead selenide PbSe nanoparticles was performed by high-energy milling of lead and selenium powder in a laboratory planetary ball mill and in an industrial eccentric vibratory mill. Structural properties of the synthesized lead selenide were characterized using X-ray diffraction that confirmed crystalline nature of PbSe nanoparticles. The average size of PbSe crystallites of 37 nm was calculated from X-ray diffraction data using the Williamson-Hall method. The methods of particle size distribution analysis, specific surface area measurement, scanning electron microscopy and transmission electron microscopy were used for characterization of surface, mean particle size, and morphology of PbSe. An application of industrial mill verified a possibility of the synthesis of a narrow bandgap semiconductor PbSe at ambient temperature and in a relatively short reaction time. (orig.)

  2. Isotopic shifts and configuration mixing in the dysprosium II spectrum

    International Nuclear Information System (INIS)

    Aufmuth, P.

    1977-01-01

    Using a photoelectric Fabry-Perot spectrometer with digital data acquisition, the isotopic shifts of all stable dysprosium isotopes (Z = 66, A = 156, 158, 160, 161, 162, 163, 164) have been measured in transitions from the groundstate configuration 4f 10 6s to the excited configurations 4f 9 5d6s, 4f 9 5d 2 , and 4f 10 6p of the spark spectrum. Mass and volume effects have been seperated; the results are compared with arc spectrum measurements. From the volume effect of a pure s-p transition the change of the mean electric quadratic nuclear radius delta 2 > has been calculated. In order to test fine structure calculations of the Dy II spectrum, the isotopic shifts of 29 lines of the isotopes 162 Dy and 164 Dy have been measured. Based on the sharing rule, the reported configuration mixing could be confirmed in principle; for one energy level (E = 22908 K) the asignement has been proved to be false, in the case of three other levels (E = 22467, 22672, and 28885 K) the asignement is doubtfull. For the ground state levels 4f 10 6s 6 I the influence of relativistic effects could be proved; these effects can be interpreted in the framework of a parametric representation of the isotopic shift. The order of magnitude of the crossed second order effects has been estimated. (orig.) [de

  3. Low Field Magnetic and Thermal Hysteresis in Antiferromagnetic Dysprosium

    Directory of Open Access Journals (Sweden)

    Iuliia Liubimova

    2017-06-01

    Full Text Available Magnetic and thermal hysteresis (difference in magnetic properties on cooling and heating have been studied in polycrystalline Dy (dysprosium between 80 and 250 K using measurements of the reversible Villari effect and alternating current (AC susceptibility. We argue that measurement of the reversible Villari effect in the antiferromagnetic phase is a more sensitive method to detect magnetic hysteresis than the registration of conventional B(H loops. We found that the Villari point, recently reported in the antiferromagnetic phase of Dy at 166 K, controls the essential features of magnetic hysteresis and AC susceptibility on heating from the ferromagnetic state: (i thermal hysteresis in AC susceptibility and in the reversible Villari effect disappears abruptly at the temperature of the Villari point; (ii the imaginary part of AC susceptibility is strongly frequency dependent, but only up to the temperature of the Villari point; (iii the imaginary part of the susceptibility drops sharply also at the Villari point. We attribute these effects observed at the Villari point to the disappearance of the residual ferromagnetic phase. The strong influence of the Villari point on several magnetic properties allows this temperature to be ranked almost as important as the Curie and Néel temperatures in Dy and likely also for other rare earth elements and their alloys.

  4. Kinetics of the nitridation of dysprosium during mechanochemical processing

    Energy Technology Data Exchange (ETDEWEB)

    Alanko, Gordon A.; Osterberg, Daniel D.; Jaques, Brian J. [Department of Materials Science and Engineering, College of Engineering, Boise State University, 1910 University Drive, Boise, ID 83725 (United States); Hurley, Michael F. [Department of Materials Science and Engineering, College of Engineering, Boise State University, 1910 University Drive, Boise, ID 83725 (United States); Center for Advanced Energy Studies, 995 University Boulevard, Idaho Falls, ID 83401 (United States); Butt, Darryl P., E-mail: darrylbutt@boisestate.edu [Department of Materials Science and Engineering, College of Engineering, Boise State University, 1910 University Drive, Boise, ID 83725 (United States); Center for Advanced Energy Studies, 995 University Boulevard, Idaho Falls, ID 83401 (United States)

    2015-01-25

    Highlights: • DyN was mechanochemically synthesized by milling pure metal under nitrogen. • Temperature and pressure were monitored to investigate reaction progress. • The effects of metal adhered to media on the impact energetics was measured. • The reactive milling kinetics are described in terms of reactive surface formation. - Abstract: Dysprosium nitride was synthesized by the reactive milling of the rare earth metal under 400 kPa nitrogen gas in a planetary ball mill. The nitrogen consumption rate was calculated from in situ temperature and pressure measurements to find the reaction extent as a function of milling time at milling speeds from 350 to 650 rpm. The results are analyzed in terms of a fundamental milling dynamics model in which the input milling energy is the primary driving force for reaction and the rate limiting step of the nitridation kinetics is the formation of chemically active surfaces. The model differs from traditional gas–solid reactions which are often limited by diffusion of a species through a surface layer or by dissociation of the gas molecule. These results give fresh insight into reactive gas–solid milling kinetics.

  5. Selenide-Based Electrocatalysts and Scaffolds for Water Oxidation Applications

    KAUST Repository

    Xia, Chuan

    2015-11-05

    Selenide-based electrocatalysts and scaffolds on carbon cloth are successfully fabricated and demonstrated for enhanced water oxidation applications. A max­imum current density of 97.5 mA cm−2 at an overpotential of a mere 300 mV and a small Tafel slope of 77 mV dec−1 are achieved, suggesting the potential of these materials to serve as advanced oxygen evolution reaction catalysts.

  6. Coulometric titration at low temperatures-nonstoichiometric silver selenide

    OpenAIRE

    Beck, Gesa K.; Janek, Jürgen

    2003-01-01

    A modified coulometric titration technique is described for the investigation of nonstoichiometric phases at low temperatures. It allows to obtain titration curves at temperatures where the conventional coulometric titration technique fails because of too small chemical diffusion coefficients of the mobile component. This method for indirect coulometric titration is applied to silver selenide between -100 and 100 °C. The titration curves are analyzed on the basis of a defect chemical model an...

  7. Selenide-Based Electrocatalysts and Scaffolds for Water Oxidation Applications

    KAUST Repository

    Xia, Chuan; Jiang, Qiu; Zhao, Chao; Hedhili, Mohamed N.; Alshareef, Husam N.

    2015-01-01

    Selenide-based electrocatalysts and scaffolds on carbon cloth are successfully fabricated and demonstrated for enhanced water oxidation applications. A max­imum current density of 97.5 mA cm−2 at an overpotential of a mere 300 mV and a small Tafel slope of 77 mV dec−1 are achieved, suggesting the potential of these materials to serve as advanced oxygen evolution reaction catalysts.

  8. Systems of pyridine, piperidine, piperazine, morpholine hydrochlorides-terbium (dysprosium) chloride-water

    International Nuclear Information System (INIS)

    Gajfutdinova, R.K.; Sharafutdinova, A.A.; Murinov, Yu.I.

    1988-01-01

    The isothermal cross section method at 25 and 50 deg C is applied to study pyridine hydrochloride-terbium chloride-water (1) piperidine hydrochloride-dysprosium chloride-water (2), piperazine dihydrochloride-dysprosium chloride-water (3) and morpholine hydrochloride-terbium chloride (4) systems. Solubility isotherma prove the formation of incongruently soluble compound of the TbCl 3 x6C 5 H 5 NxHCl composition systems (1). The individuality of the new solid phase is proved by the chemical and DTA methods. Systems (2-4) are of a simple eutonic type

  9. Exploration of dysprosium: the most critical element for Japan

    Science.gov (United States)

    Watanabe, Y.

    2012-04-01

    Dysprosium (Dy), one of the heavy rare earth elements, is used mainly as an additive for NdFeB permanent magnets which are installed in various modern industrial products such as voice coil motors in computers, factory automation machinery, hybrid and electric vehicles, home electronics, and wind turbine, to improve heat resistance of the magnets. Dy has been produced about 2,000t per year from the ores from ion adsorption type deposits in southern China. However, the produced amount of Dy was significantly reduced in 2011 in China due to reservation of heavy rare earth resources and protection of natural environment, resulting in soaring of Dy price in the world. In order to respond the increasing demand of Dy, unconventional supply sources are inevitably developed, in addition to heavy rare earth enriched ion adsorption type deposits outside China. Heavy rare earth elements including Dy are dominantly hosted in xenotime, fergusonite, zircon, eudialyte, keiviite, kainosite, iimoriite, etc. Concentration of xenotime is found in placer deposits in Malaysia and India, hydrothermal deposits associated with unconformity-type uranium mineralization (Athabasca basin in Canada, Western Australia), iron-oxide fluorite mineralization (South Africa) and Sn-bearing alkaline granite (Brazil). Zircon and fergusontie concentration is found as igneous and hydrothermal products in peralkaline syenite, alkaline granite and pegmatite (e.g., Nechalacho in Canada). Eudialyte concentration is found in some peralkaline syenite bodies in Greenland, Canada, Sweden and Russia. Among these sources, large Dy resources are estimated in the deposits hosted in peralkaline rocks (Nechalacho: 79,000t, Kvanefjeld: 49,000t, Norra Karr: 15,700t, etc.) compared to the present demand of Dy. Thus, Dy will be supplied from the deposits associated with peralkaline and alkaline deposits in future instead of ion adsorption type deposits in southern China.

  10. Asymmetric supercapacitors with metal-like ternary selenides and porous graphene electrodes

    KAUST Repository

    Xia, Chuan; Jiang, Qiu; Zhao, Chao; Beaujuge, Pierre; Alshareef, Husam N.

    2016-01-01

    nanostructured ternary nickel cobalt selenides result in a much higher areal capacitance (2.33 F cm−2 at 4 mA cm−2), better rate performance and cycling stability than their binary selenide equivalents, and other ternary oxides and chalcogenides. Those hybrid

  11. Vapor transport deposition of antimony selenide thin film solar cells with 7.6% efficiency.

    Science.gov (United States)

    Wen, Xixing; Chen, Chao; Lu, Shuaicheng; Li, Kanghua; Kondrotas, Rokas; Zhao, Yang; Chen, Wenhao; Gao, Liang; Wang, Chong; Zhang, Jun; Niu, Guangda; Tang, Jiang

    2018-06-05

    Antimony selenide is an emerging promising thin film photovoltaic material thanks to its binary composition, suitable bandgap, high absorption coefficient, inert grain boundaries and earth-abundant constituents. However, current devices produced from rapid thermal evaporation strategy suffer from low-quality film and unsatisfactory performance. Herein, we develop a vapor transport deposition technique to fabricate antimony selenide films, a technique that enables continuous and low-cost manufacturing of cadmium telluride solar cells. We improve the crystallinity of antimony selenide films and then successfully produce superstrate cadmium sulfide/antimony selenide solar cells with a certified power conversion efficiency of 7.6%, a net 2% improvement over previous 5.6% record of the same device configuration. We analyze the deep defects in antimony selenide solar cells, and find that the density of the dominant deep defects is reduced by one order of magnitude using vapor transport deposition process.

  12. Dosimetric properties of dysprosium doped lithium borate glass irradiated by 6 MV photons

    Science.gov (United States)

    Ab Rasid, A.; Wagiran, H.; Hashim, S.; Ibrahim, Z.; Ali, H.

    2015-07-01

    Undoped and dysprosium doped lithium borate glass system with empirical formula (70-x) B2O3-30 Li2O-(x) Dy2O3 (x=0.1, 0.3, 0.5, 0.7, 1.0 mol%) were prepared using the melt-quenching technique. The dosimetric measurements were performed by irradiating the samples to 6 MV photon beam using linear accelerator (LINAC) over a dose range of 0.5-5.0 Gy. The glass series of dysprosium doped lithium borate glass produced the best thermoluminescence (TL) glow curve with the highest intensity peak from sample with 1.0 mol% Dy2O3 concentration. Minimum detectable dose was detected at 2.24 mGy, good linearity of regression coefficient, high reproducibility and high sensitivity compared to the undoped glass are from 1.0 mol% dysprosium doped lithium borate glass. The results indicated that the series of dysprosium doped lithium glasses have a great potential to be considered as a thermoluminescence dosimetry (TLD).

  13. In situ characterization of the nitridation of dysprosium during mechanochemical processing

    Energy Technology Data Exchange (ETDEWEB)

    Jaques, Brian J.; Osterberg, Daniel D.; Alanko, Gordon A.; Tamrakar, Sumit; Smith, Cole R.; Hurley, Michael F.; Butt, Darryl P., E-mail: DarrylButt@BoiseState.edu

    2015-01-15

    Highlights: • A nitridation reaction in a high energy planetary ball mill was monitored in situ. • Dysprosium mononitride was synthesized from Dy at low temperatures in short times. • Ideal gas law and in situ temperature and pressure used to assess reaction extent. • It is proposed that reaction rate is proportional to the creation of new surface. - Abstract: Processing of advanced nitride ceramics traditionally requires long durations at high temperatures and, in some cases, in hazardous atmospheres. In this study, dysprosium mononitride (DyN) was rapidly formed from elemental dysprosium in a closed system at ambient temperatures. An experimental procedure was developed to quantify the progress of the nitridation reaction during mechanochemical processing in a high energy planetary ball mill (HEBM) as a function of milling time and intensity using in situ temperature and pressure measurements, SEM, XRD, and particle size analysis. No intermediate phases were formed. It was found that the creation of fresh dysprosium surfaces dictates the rate of the nitridation reaction, which is a function of milling intensity and the number of milling media. These results show clearly that high purity nitrides can be synthesized with short processing times at low temperatures in a closed system requiring a relatively small processing footprint.

  14. A model for additive transport in metal halide lamps containing mercury and dysprosium tri-iodide

    NARCIS (Netherlands)

    Beks, M.L.; Haverlag, M.; Mullen, van der J.J.A.M.

    2008-01-01

    The distribution of additives in a metal halide lamp is examined through numerical modelling. A model for a lamp containing sodium iodide additives has been modified to study a discharge containing dysprosium tri-iodide salts. To study the complex chemistry the method of Gibbs minimization is used

  15. Neutronography of an intermediate phase in dysprosium near the Neel point

    Energy Technology Data Exchange (ETDEWEB)

    Bessergenev, V G; Gogava, V V; Kovalevskaya, Yu A; Mandzhavidze, A G; Fedorov, V M; Shilo, S I

    1985-11-25

    Neutronographical study of dysprosium magnetic structure near the point of magnetic disordering depending on thermal prehistory of the sample is carried out. Intermediate vortex phase transformed then into the helical one is shown to occur from the paramagnetic phase under cooling.

  16. Synthesis and X-ray structure of the dysprosium(III) complex derived ...

    African Journals Online (AJOL)

    Synthesis and X-ray structure of the dysprosium(III) complex derived from the ligand 5-chloro-1 ... Bulletin of the Chemical Society of Ethiopia ... synthesized and its crystal structure determined by single X-ray diffraction at room temperature.

  17. Dysprosium-containing layered double hydroxides nanoparticles intercalated with biologically active species as an approach for theranostic systems

    KAUST Repository

    Arratia-Quijada, Jenny

    2015-10-23

    A layered double hydroxide structure including dysprosium cations was prepared by co-precipitation. The nanoparticles showed a linear relationship with the reciprocal relaxation spin-lattice (T1) time of water protons which is reflected as contrast in aqueous suspensions analyzed by magnetic resonance imaging. The interlayer space of dysprosium containing LDH was successfully intercalated with folate, ibuprofen and gallate ions, which are key molecules for recognition of some cancer cells and treatment of diseases. The paramagnetic property of the dysprosium-containing LDH detected in this work beside the ability to transport drugs open up the opportunity to design theranostic materials in a single crystal phase with nanometric dimensions.

  18. Dysprosium-containing layered double hydroxides nanoparticles intercalated with biologically active species as an approach for theranostic systems

    KAUST Repository

    Arratia-Quijada, Jenny; Sá nchez Jimé nez, Cecilia; Gurinov, Andrei; Pé rez Centeno, Armando; Ceja Andrade, Israel; Carbajal Arí zaga, Gregorio Guadalupe

    2015-01-01

    A layered double hydroxide structure including dysprosium cations was prepared by co-precipitation. The nanoparticles showed a linear relationship with the reciprocal relaxation spin-lattice (T1) time of water protons which is reflected as contrast in aqueous suspensions analyzed by magnetic resonance imaging. The interlayer space of dysprosium containing LDH was successfully intercalated with folate, ibuprofen and gallate ions, which are key molecules for recognition of some cancer cells and treatment of diseases. The paramagnetic property of the dysprosium-containing LDH detected in this work beside the ability to transport drugs open up the opportunity to design theranostic materials in a single crystal phase with nanometric dimensions.

  19. Extinction in an extended-face crystal of zinc selenide

    International Nuclear Information System (INIS)

    Stevenson, A.W.; Barnea, Z.

    1982-01-01

    X-ray intensity measurements from an extended-face single crystal of cubic zinc selenide obtained by McIntyre, Moss and Barnea (1980) have been re-analysed with a view to explaining the unresolved discrepancies between theory and experiment present in the original analysis of the most severely extinguished reflections. The results are shown to complement the recent findings of a wavelength dependent study using the same crystal specimen and foreshadow the need to allow for the presence of the Borrmann effect

  20. Adsorption and gas-chromatographic properties of tungsten selenide

    International Nuclear Information System (INIS)

    Gavrilova, T.B.; Kiselev, A.V.; Roshchina, T.M.

    1988-01-01

    Method of gas chromatography was used to investigate the surface properties of a series of tungsten selenide WSe 2 samples as well as to determine the role of geometrical and electronic structure of adsorbate molecules and their orientation with respect to the surface during adsorption on WSe 2 . Thermodynamic characteristics of hydrocarbon C 6 -C 10 adsorption at surface occupation close to the zero one were determined. Correlation of the values of thermodynamic characteristics of saturated and aromatic hydrocarbon adsorption enabled to refer WSe 2 to nonspecific adsorbents. It is noted that the main role during hydrocarbon adsorption on WSe 2 is played by nonpolar basic facets, occupied by selenium atoms

  1. Dysprosium complexes with the tetraphenylporphyrin macrocyclic ligand; Complejos de disprosio con el ligante macrociclico tetrafenilporfirina

    Energy Technology Data Exchange (ETDEWEB)

    Martinez M, V.; Padilla, J.; Ramirez, F.M

    1992-04-15

    In this report, the results obtained on the synthesis, characterization and study of the chemical behavior of dysprosium complex with the acetylacetone chelating agent (Hacac) and the tetraphenylporphyrin macrocyclic ligand (H{sub 2}TFP) are given. Based on the literature but according to our necessities and interest, the appropriate methodology settled down from the synthesis of prime matters until the obtaining and characterization of the products. The acetyl acetonate complex was obtained of mono hydrated dysprosium [Dy(acac){sub 3}. H{sub 2}0] and trihydrated [Dy(acac){sub 3} .3 H{sub 2}0], the mono tetra phenyl porphyrinate [Dy(TFP)(acac). 2 ac] the double sandwich of the dysprosium porphyrinate [Dy(TFP){sub 2}] and the triple sandwich of the dysprosium porphyrinate [Dy(TFP){sub 3}. 2 TCB] (TCB = trichlorobenzene). Its were characterized by their melting points, solubility, IR, UV, TGA and DTA both first and besides the techniques already mentioned for NMR'H, RPE and Magnetic susceptibility the three last complexes. From the spectroscopic point of view, IR and RPE its suggested the existence of a complex of inverse mixed valence [Dy(TFP){sup 2-} (TFP) {sup 1-}] for the Dy(TFP){sub 2} as a result of the existence of the free radical (TFP' {sup 1-} and that it was not in none of the other porphyrin compounds. In the NMR'H spectra of the compounds were not observed signals in the region from 0 to 10 ppm that which shows that the dysprosium complexes in special those of the porphyrin type are highly paramagnetic and its could be used as displacement reagents, creators of images and contrast agents of great utility in these days in studies of NMR, technique today by today used in medical diagnoses. (Author)

  2. Dysprosium complexes with the tetraphenylporphyrin macrocyclic ligand; Complejos de disprosio con el ligante macrociclico tetrafenilporfirina

    Energy Technology Data Exchange (ETDEWEB)

    Martinez M, V; Padilla, J; Ramirez, F M

    1992-04-15

    In this report, the results obtained on the synthesis, characterization and study of the chemical behavior of dysprosium complex with the acetylacetone chelating agent (Hacac) and the tetraphenylporphyrin macrocyclic ligand (H{sub 2}TFP) are given. Based on the literature but according to our necessities and interest, the appropriate methodology settled down from the synthesis of prime matters until the obtaining and characterization of the products. The acetyl acetonate complex was obtained of mono hydrated dysprosium [Dy(acac){sub 3}. H{sub 2}0] and trihydrated [Dy(acac){sub 3} .3 H{sub 2}0], the mono tetra phenyl porphyrinate [Dy(TFP)(acac). 2 ac] the double sandwich of the dysprosium porphyrinate [Dy(TFP){sub 2}] and the triple sandwich of the dysprosium porphyrinate [Dy(TFP){sub 3}. 2 TCB] (TCB = trichlorobenzene). Its were characterized by their melting points, solubility, IR, UV, TGA and DTA both first and besides the techniques already mentioned for NMR'H, RPE and Magnetic susceptibility the three last complexes. From the spectroscopic point of view, IR and RPE its suggested the existence of a complex of inverse mixed valence [Dy(TFP){sup 2-} (TFP) {sup 1-}] for the Dy(TFP){sub 2} as a result of the existence of the free radical (TFP' {sup 1-} and that it was not in none of the other porphyrin compounds. In the NMR'H spectra of the compounds were not observed signals in the region from 0 to 10 ppm that which shows that the dysprosium complexes in special those of the porphyrin type are highly paramagnetic and its could be used as displacement reagents, creators of images and contrast agents of great utility in these days in studies of NMR, technique today by today used in medical diagnoses. (Author)

  3. Dysprosium, the balance problem, and wind power technology

    International Nuclear Information System (INIS)

    Elshkaki, Ayman; Graedel, T.E.

    2014-01-01

    Highlights: • We investigate the impacts of the increasing market share of wind power on the demand and supply of REE. • The analysis is carried out using a dynamic material flow and stock model and three scenarios for Dy supply. • The supply of Dy from all deposits will likely lead to an oversupply of the total REEs, Nd, La, Ce and Y. • The supply of Dy from critical REE or Dy rich deposits will likely lead to an oversupply of Ce and Y only. • Large quantities of thorium will be co-produced as a result of Dy demand that needs to be managed carefully. - Abstract: Wind power technology is one of the cleanest electricity generation technologies that are expected to have a substantial share in the future electricity mix. Nonetheless, the expected increase in the market share of wind technology has led to an increasing concern of the availability, production capacity and geographical concentration of the metals required for the technology, especially the rear earth elements (REE) neodymium (Nd) and the far less abundant dysprosium (Dy), and the impacts associated with their production. Moreover, Nd and Dy are coproduced with other rare earth metals mainly from iron, titanium, zirconium, and thorium deposits. Consequently, an increase in the demand for Nd and Dy in wind power technology and in their traditional applications may lead to an increase in the production of the host metals and other companion REE, with possible implications on their supply and demand. In this regard, we have used a dynamic material flow and stock model to study the impacts of the increasing demand for Nd and Dy on the supply and demand of the host metals and other companion REE. In one scenario, when the supply of Dy is covered by all current and expected producing deposits, the increase in the demand for Dy leads to an oversupply of 255 Gg of total REE and an oversupply of the coproduced REE Nd, La, Ce and Y. In the second and third scenarios, however, when the supply of Dy is

  4. Dysprosium-containing layered double hydroxides nanoparticles intercalated with biologically active species as an approach for theranostic systems

    Energy Technology Data Exchange (ETDEWEB)

    Arratia-Quijada, Jenny [Departamento de Ciencias de la Salud, Centro Universitario Tonalá, Universidad de Guadalajara, Av. Nuevo Periférico No. 555, C.P. 48525, Tonalá, Jalisco (Mexico); Sánchez Jiménez, Cecilia [Departamento de Química, Universidad de Guadalajara, Boulevard Marcelino García Barragán 1421, C.P. 44430, Guadalajara, Jalisco (Mexico); Gurinov, Andrey [Research Resources Center for Magnetic Resonance, St. Petersburg State University, Universitetskiy pr. 26, 198504 St. Petersburg (Russian Federation); NMR Core Lab, King Abdullah University of Science and Technology, Thuwal 23955-6900 (Saudi Arabia); Pérez Centeno, Armando; Ceja Andrade, Israel [Departamento de Física, Universidad de Guadalajara, Boulevard Marcelino García Barragán 1421, C.P. 44430, Guadalajara, Jalisco (Mexico); Carbajal Arízaga, Gregorio Guadalupe, E-mail: gregoriocarbajal@yahoo.com.mx [Departamento de Química, Universidad de Guadalajara, Boulevard Marcelino García Barragán 1421, C.P. 44430, Guadalajara, Jalisco (Mexico)

    2016-01-15

    Graphical abstract: - Highlights: • LDH structure including dysprosium was prepared by co-precipitation. • LDH was capable to produce contrast in the T1 mode of MRI. • LDH were intercalated with folate, ibuprofen and gallate ions. - Abstract: A layered double hydroxide structure including dysprosium cations was prepared by co-precipitation. The nanoparticles showed a linear relationship with the reciprocal relaxation spin-lattice (T1) time of water protons which is reflected as contrast in aqueous suspensions analyzed by magnetic resonance imaging. The interlayer space of dysprosium containing LDH was successfully intercalated with folate, ibuprofen and gallate ions, which are key molecules for recognition of some cancer cells and treatment of diseases. The paramagnetic property of the dysprosium-containing LDH detected in this work beside the ability to transport drugs open up the opportunity to design theranostic materials in a single crystal phase with nanometric dimensions.

  5. Dysprosium-containing layered double hydroxides nanoparticles intercalated with biologically active species as an approach for theranostic systems

    International Nuclear Information System (INIS)

    Arratia-Quijada, Jenny; Sánchez Jiménez, Cecilia; Gurinov, Andrey; Pérez Centeno, Armando; Ceja Andrade, Israel; Carbajal Arízaga, Gregorio Guadalupe

    2016-01-01

    Graphical abstract: - Highlights: • LDH structure including dysprosium was prepared by co-precipitation. • LDH was capable to produce contrast in the T1 mode of MRI. • LDH were intercalated with folate, ibuprofen and gallate ions. - Abstract: A layered double hydroxide structure including dysprosium cations was prepared by co-precipitation. The nanoparticles showed a linear relationship with the reciprocal relaxation spin-lattice (T1) time of water protons which is reflected as contrast in aqueous suspensions analyzed by magnetic resonance imaging. The interlayer space of dysprosium containing LDH was successfully intercalated with folate, ibuprofen and gallate ions, which are key molecules for recognition of some cancer cells and treatment of diseases. The paramagnetic property of the dysprosium-containing LDH detected in this work beside the ability to transport drugs open up the opportunity to design theranostic materials in a single crystal phase with nanometric dimensions.

  6. Interaction distances in oxides, sulfides and selenides with face-centered packing

    International Nuclear Information System (INIS)

    Kesler, Ya.A.

    1993-01-01

    Concept of characteristic distances (CD) was specified with account of the principle of topologically face-centered anion packing: calculation method was presented and boundary conditions of CD concept applicability were considered. Tables of CD in oxides, sulfides and selenides, obtained in result of self-consistent calculations on the basis of experimental crystallographic data, are presented. Pair correlations between CD in oxides, sulfides and selenides were considered, their relationship with cation electron structure was established. Peculiarities of chemical bond in oxides, sulfides and selenides with face-centered anion packing were discussed

  7. A facile way to control phase of tin selenide flakes by chemical vapor deposition

    Science.gov (United States)

    Wang, Zhigang; Pang, Fei

    2018-06-01

    Although two-dimensional (2D) tin selenides are attracting intense attentions, studies on its phase transition are still relatively few. Here we report a facile way to control the phase growth of tin selenide flakes on mica and SiO2/Si by only adjusting nominal Sn:Se ratio, which refers to the amount of loaded SnO2 and Se precursors. High normal Sn:Se ratio induced SnSe flakes, conversely SnSe2 flakes formed. It could be used as a practical guide to selectively synthesize pure phase of single crystalline 2D layered chalcogenide materials similar to tin selenides.

  8. Green Hydroselenation of Aryl Alkynes: Divinyl Selenides as a Precursor of Resveratrol

    Directory of Open Access Journals (Sweden)

    Gelson Perin

    2017-02-01

    Full Text Available A simple and efficient protocol to prepare divinyl selenides has been developed by the regio- and stereoselective addition of sodium selenide species to aryl alkynes. The nucleophilic species was generates in situ, from the reaction of elemental selenium with NaBH4, utilizing PEG-400 as the solvent. Several divinyl selenides were obtained in moderate to excellent yields with selectivity for the (Z,Z-isomer by a one-step procedure that was carried out at 60 °C in short reaction times. The methodology was extended to tellurium, giving the desired divinyl tellurides in good yields. Furthermore, the Fe-catalyzed cross-coupling reaction of bis(3,5-dimethoxystyryl selenide 3f with (4-methoxyphenylmagnesium bromide 5 afforded resveratrol trimethyl ether 6 in 57% yield.

  9. In Silico Studies of Mammalian δ-ALAD Interactions with Selenides and Selenoxides.

    Science.gov (United States)

    Andrei Nogara, Pablo; Batista Teixeira Rocha, João

    2018-04-01

    Previous studies have shown that the mammalian δ-aminolevulinic acid dehydratase (δ-ALAD) is inhibited by selenides and selenoxides, which can involve thiol oxidation. However, the precise molecular interaction of selenides and selenoxides with the active center of the enzyme is unknown. Here, we try to explain the interaction of selenides and the respective selenoxides with human δ-ALAD by in silico molecular docking. The in silico data indicated that Se atoms of selenoxides have higher electrophilic character than their respective selenides. Further, the presence of oxygen increased the interaction of selenoxides with the δ-ALAD active site by O…Zn coordination. The interaction of S atom from Cys124 with the Se atom indicated the importance of the nucleophilic attack of the enzyme thiolate to the organoselenium molecules. These observations help us to understand the interaction of target proteins with organoselenium compounds. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Green Hydroselenation of Aryl Alkynes: Divinyl Selenides as a Precursor of Resveratrol.

    Science.gov (United States)

    Perin, Gelson; Barcellos, Angelita M; Luz, Eduardo Q; Borges, Elton L; Jacob, Raquel G; Lenardão, Eder J; Sancineto, Luca; Santi, Claudio

    2017-02-20

    A simple and efficient protocol to prepare divinyl selenides has been developed by the regio- and stereoselective addition of sodium selenide species to aryl alkynes. The nucleophilic species was generates in situ , from the reaction of elemental selenium with NaBH₄, utilizing PEG-400 as the solvent. Several divinyl selenides were obtained in moderate to excellent yields with selectivity for the ( Z , Z )-isomer by a one-step procedure that was carried out at 60 °C in short reaction times. The methodology was extended to tellurium, giving the desired divinyl tellurides in good yields. Furthermore, the Fe-catalyzed cross-coupling reaction of bis(3,5-dimethoxystyryl) selenide 3f with (4-methoxyphenyl)magnesium bromide 5 afforded resveratrol trimethyl ether 6 in 57% yield.

  11. Dysprosium-Catalyzed Growth of Single-Walled Carbon Nanotube Arrays on Substrates

    Directory of Open Access Journals (Sweden)

    Qian Yong

    2009-01-01

    Full Text Available Abstract In this letter, we report that dysprosium is an effective catalyst for single-walled carbon nanotubes (SWNTs growth via a chemical vapor deposition (CVD process for the first time. Horizontally superlong well-oriented SWNT arrays on SiO2/Si wafer can be fabricated by EtOH-CVD under suitable conditions. The structure and properties are characterized by scanning electron microscopy, transition electron microscopy, Raman spectroscopy and atomic force microscopy. The results show that the SWNTs from dysprosium have better structural uniformity and better conductivity with fewer defects. This rare earth metal provides not only an alternative catalyst for SWNTs growth, but also a possible method to generate high percentage of superlong semiconducting SWNT arrays for various applications of nanoelectronic device.

  12. Sandwich-type tetrakis(phthalocyaninato) dysprosium-cadmium quadruple-decker SMM.

    Science.gov (United States)

    Wang, Hailong; Qian, Kang; Wang, Kang; Bian, Yongzhong; Jiang, Jianzhuang; Gao, Song

    2011-09-14

    Homoleptic tetrakis[2,3,9,10,16,17,23,24-octa(butyloxy)phthalocyaninato] dysprosium-cadmium quadruple-decker complex 1 was isolated in relatively good yield of 43% from a simple one-pot reaction. This compound represents the first sandwich-type tetrakis(phthalocyaninato) rare earth-cadmium quadruple-decker SMM that has been structurally characterized. This journal is © The Royal Society of Chemistry 2011

  13. {Delta}I = 2 energy staggering in normal deformed dysprosium nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Riley, M.A.; Brown, T.B.; Archer, D.E. [Florida State Univ., Tallahassee, FL (United States)] [and others

    1996-12-31

    Very high spin states (I{ge}50{Dirac_h}) have been observed in {sup 155,156,157}Dy. The long regular band sequences, free from sharp backbending effects, observed in these dysprosium nuclei offer the possibility of investigating the occurence of any {Delta}I = 2 staggering in normal deformed nuclei. Employing the same analysis techniques as used in superdeformed nuclei, certain bands do indeed demonstrate an apparent staggering and this is discussed.

  14. Analysis of the x-ray spectrum emitted by laser-produced plasma of dysprosium

    International Nuclear Information System (INIS)

    Marcus, Gilad; Louzon, Einat; Henis, Zohar; Maman, Shlomo; Mandelbaum, Pinchas

    2007-01-01

    A detailed analysis of the x-ray spectrum (5-10.2 A ring ) emitted by laser-produced plasma of dysprosium (Dy) is given using ab initio calculations with the HULLAC relativistic code and isoelectronic trends. Resonance 3d-4p, 3d-nf (n=4 to 7), 3p-4s, and 3p-4d transitions of Ni I-like Dy XXXIX and neighboring ion satellite transitions (from Dy XXXIV to Dy XL) are identified

  15. Selenide isotope generator for the Galileo mission. Reliability program plan

    International Nuclear Information System (INIS)

    1978-10-01

    The reliability program plan for the Selenide Isotope Generator (SIG) program is presented. It delineates the specific tasks that will be accomplished by Teledyne Energy Systems and its suppliers during design, development, fabrication and test of deliverable Radioisotopic Thermoelectric Generators (RTG), Electrical Heated Thermoelectric Generators (ETG) and associated Ground Support Equipment (GSE). The Plan is formulated in general accordance with procedures specified in DOE Reliability Engineering Program Requirements Publication No. SNS-2, dated June 17, 1974. The Reliability Program Plan presented herein defines the total reliability effort without further reference to Government Specifications. The reliability tasks to be accomplished are delineated herein and become the basis for contract compliance to the extent specified in the SIG contract Statement of Work

  16. Phosphor Dysprosium-Doped Layered Double Hydroxides Exchanged with Different Organic Functional Groups

    Directory of Open Access Journals (Sweden)

    David Ricardo Martínez Vargas

    2013-01-01

    Full Text Available The layers of a Zn/Al layered double hydroxide (LDH were doped with Dy3+ cations. Among some compositions, the Zn2+ : Al3+ : Dy3+ molar ratio equal to 30 : 9 : 1 presented a single crystalline phase. Organic anions with carboxylic, amino, sulfate, or phosphate functional groups were intercalated as single layers between LDH layers as confirmed by X-ray diffraction and infrared spectroscopy. Photoluminescence spectra of the nitrate intercalated LDH showed a wide emission band with strong intensity in the yellow region (around 574 nm, originated due to symmetry distortion of the octahedral coordination in dysprosium centers. Moreover, a broad red band emission was also detected apparently due to the presence of zinc oxide. The distorted symmetry of the dysprosium coordination environment, also confirmed by X-ray photoelectron spectroscopy analysis, was modified after the intercalation with phenyl phosphonate (PP, aspartate (Asp, adipate (Adip, and serinate (Ser anions; the emission as measured from PL spectra of these LDH was more intense in the blue region (ca. 486 nm, thus indicating an increase in symmetry of dysprosium octahedrons. The red emission band from zinc oxide kept the same intensity after intercalation of dodecyl sulfate (DDS. An additional emission of unknown origin at λ = 767 nm was present in all LDHs.

  17. Synovectomy of the rheumatoid knee using intra-articular injection of dysprosium-165-ferric hydroxide macroaggregates

    International Nuclear Information System (INIS)

    Sledge, C.B.; Zuckerman, J.D.; Shortkroff, S.; Zalutsky, M.R.; Venkatesan, P.; Snyder, M.A.; Barrett, W.P.

    1987-01-01

    One hundred and eleven patients who had seropositive rheumatoid arthritis and persistent synovitis of the knee were treated with intra-articular injection of 270 millicuries of dysprosium-165 bound to ferric hydroxide macroaggregates. A two-year follow-up was available for fifty-nine of the treated knees. Thirty-nine had a good result; nine, a fair result; and eleven, a poor result. Of the twenty-five knees that had Stage-I radiographic changes, nineteen had a good result. Of the thirty-four knees that had Stage-II radiographic changes, twenty showed a good result. Systemic spread of the radioactivity from the injected joint was minimum. The mean whole-body dose was calculated to be 0.3 rad and that to the liver twenty-four hours after injection, 3.2 rads. The results indicated that dysprosium-165-ferric hydroxide macroaggregate is an effective agent for performing radiation synovectomy, particularly in knees that have Stage-I radiographic changes. Because of the minimum rate of systemic spread of the dysprosium-165, it offers a definite advantage over agents that previously have been used

  18. Development and mastering of production of dysprosium hafnate as absorbing material for control rods of promising thermal neutron reactors

    International Nuclear Information System (INIS)

    Zakharov, A.V.; Risovany, V.D.; Muraleva, E.M.; Sokolov, V.F.

    2011-01-01

    The main advantages of dysprosium hafnate as an absorbing material for LWR control rods are the following: -) unlimited radiation resistance; - two absorbing components, Dy and Hf, increasing physical efficiency of the material compared to Dy 2 O 3 -TiO 2 and alloy 80% Ag - 15% In - 5% Cd; -) variability of physical efficiency by changing a composition, but maintaining other performance characteristics of the material; -) high process-ability due to the absence of phase transients and single-phase structure (solid solution); -) production of high density pellets. Lab-scale mastering of dysprosium hafnate pellets production showed a possibility of material synthesis using a solid-phase method, as well as of dysprosium hafnate pellets production by cold pressing and subsequent sintering. Within a whole range of examined compositions (23 mol% - 75 mol% Dy 2 O 3 ), a single-phase material with a highly radiation resistant fluorite-like structure was produced. Experiments on cold pressing and sintering of pellets confirmed a possibility of producing high quality dysprosium hafnate pellets from synthesized powder. A pilot batch of dysprosium hafnate pellets with standard sizes was produced. The standard sizes corresponded to the absorbing elements of the WWER-1000 control rods and met the main requirements to the absorbing element columns. The pilot batch size was approximately 6 kg. Acceptance testing of the pilot batch of dysprosium hafnate pellets was conducted, fulfillment of the requirements of technical conditions was checked and preirradiation properties of the pellets were examined. High quality of the produced pellets was confirmed, thus, demonstrating a real possibility of producing large batches of the dysprosium hafnate pellets. The next step is the production of test absorbing elements and cluster assemblies for the WWER-1000 control rods with their further installation for pilot operation at one of the Russian nuclear power plants

  19. Systematic study on surface and magnetostructural changes in Mn-substituted dysprosium ferrite by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Rekha, G. [Department of Physics, College of Engineering Guindy, Anna University, Sardar Patel Road, Chennai 600025 (India); Tholkappiyan, R. [Department of Physics, College of Engineering Guindy, Anna University, Sardar Patel Road, Chennai 600025 (India); Department of Physics, College of Science, UAE University, Al-Ain 15551 (United Arab Emirates); Vishista, K., E-mail: raovishista@gmail.com [Department of Physics, College of Engineering Guindy, Anna University, Sardar Patel Road, Chennai 600025 (India); Hamed, Fathalla [Department of Physics, College of Science, UAE University, Al-Ain 15551 (United Arab Emirates)

    2016-11-01

    Highlights: • Garnet type Dy{sub 3}Fe{sub 5-x}Mn{sub x}O{sub 12} (x = 0–0.06) nanoparticles of 88.4–86.8 nm were synthesized by hydrothermal method. • The Dy, Mn, Fe and O elements in the ferrites were confirmed from XPS. • The multiple oxidation states of Fe and Mn ions, bonding energy and cationic distributions of the samples were examined by XPS. • The magnetic property shows ferromagnetic behavior from VSM technique. • The results from these studies are correlated with respect to Mn dopant. - Abstract: Dysprosium iron garnets are of scientific importance because of the wide range of magnetic properties that can be obtained in substituting dysprosium by a rare earth metal. In the present work, the effect of Mn substitution on magnetostructural changes in dysprosium ferrite nanoparticles is studied. Highly crystalline pure and Mn doped dysprosium ferrite nanoparticles were synthesized by hydrothermal method. The samples were calcined at 1100 °C for 2 h in air atmosphere which is followed by characterization using XRD, FT-IR analysis, SEM, XPS and VSM. The average crystallite size of synthesized samples were calculated by X-ray diffraction falls in the range of 88.4–86.8 nm and was found to be in cubic garnet structure. For further investigation of the structure and corresponding changes in the tetrahedral and octahedral stretching vibrational bonds, FT-IR was used. The synthesized samples consist of multiple oxidation (Fe{sup 3+} and Fe{sup 2+}) states for Fe ions and (Mn{sup 3+} and Mn{sup 2+}) Mn ions analyzed in three ways of Fe 2p and Mn 2p spectra from the XPS analysis. With respect to Mn dopant in Dy{sub 3}Fe{sub 5}O{sub 12}, the cationic distributions of elements were discussed from high resolution XPS spectra by peak position and shift, area, width. To find out the porous/void surface morphology of the sample, scanning electron microscopy was used. From XPS analysis, the presence of elements (Dy, Mn, Fe and O) and their composition in the

  20. Synthesis, structural characterization and in vitro testing of dysprosium containing silica particles as potential MRI contrast enhancing agents

    Energy Technology Data Exchange (ETDEWEB)

    Chiriac, L.B.; Trandafir, D.L. [Faculty of Physics & National Magnetic Resonance Center, Babeş-Bolyai University, Cluj-Napoca, RO-400084 (Romania); Interdisciplinary Research Institute on Bio-Nano-Sciences & Faculty of Physics, Babeş-Bolyai University, Cluj-Napoca, RO-400084 (Romania); Turcu, R.V.F. [Faculty of Physics & National Magnetic Resonance Center, Babeş-Bolyai University, Cluj-Napoca, RO-400084 (Romania); Todea, M. [Interdisciplinary Research Institute on Bio-Nano-Sciences & Faculty of Physics, Babeş-Bolyai University, Cluj-Napoca, RO-400084 (Romania); Simon, S., E-mail: simons@phys.ubbcluj.ro [Faculty of Physics & National Magnetic Resonance Center, Babeş-Bolyai University, Cluj-Napoca, RO-400084 (Romania); Interdisciplinary Research Institute on Bio-Nano-Sciences & Faculty of Physics, Babeş-Bolyai University, Cluj-Napoca, RO-400084 (Romania)

    2016-11-01

    Highlights: • Dysprosium containing silica microparticles obtained by freeze and spray drying. • Higher structural units interconnection achieved in freeze vs. spray dried samples. • Dy occurance on the outermost layer of the microparticles evidenced by XPS. • Enhanced MRI contrast observed for freeze dried samples with 5% mol Dy{sub 2}O{sub 3}. - Abstract: The work is focused on synthesis and structural characterization of novel dysprosium-doped silica particles which could be considered as MRI contrast agents. Sol-gel derived silica rich particles obtained via freeze-drying and spray-drying processing methods were structurally characterized by XRD, {sup 29}Si MAS-NMR and XPS methods. The occurrence of dysprosium on the outermost layer of dysprosium containing silica particles was investigated by XPS analysis. The MRI contrast agent characteristics have been tested using RARE-T{sub 1} and RARE-T{sub 2} protocols. The contrast of MRI images delivered by the investigated samples was correlated with their local structure. Dysprosium disposal on microparticles with surface structure characterised by decreased connectivity of the silicate network units favours dark T{sub 2}-weighted MRI contrast properties.

  1. Synthesis, structural characterization and in vitro testing of dysprosium containing silica particles as potential MRI contrast enhancing agents

    International Nuclear Information System (INIS)

    Chiriac, L.B.; Trandafir, D.L.; Turcu, R.V.F.; Todea, M.; Simon, S.

    2016-01-01

    Highlights: • Dysprosium containing silica microparticles obtained by freeze and spray drying. • Higher structural units interconnection achieved in freeze vs. spray dried samples. • Dy occurance on the outermost layer of the microparticles evidenced by XPS. • Enhanced MRI contrast observed for freeze dried samples with 5% mol Dy_2O_3. - Abstract: The work is focused on synthesis and structural characterization of novel dysprosium-doped silica particles which could be considered as MRI contrast agents. Sol-gel derived silica rich particles obtained via freeze-drying and spray-drying processing methods were structurally characterized by XRD, "2"9Si MAS-NMR and XPS methods. The occurrence of dysprosium on the outermost layer of dysprosium containing silica particles was investigated by XPS analysis. The MRI contrast agent characteristics have been tested using RARE-T_1 and RARE-T_2 protocols. The contrast of MRI images delivered by the investigated samples was correlated with their local structure. Dysprosium disposal on microparticles with surface structure characterised by decreased connectivity of the silicate network units favours dark T_2-weighted MRI contrast properties.

  2. Synthesis, characterization and sup 23 Na NMR shift studies of a novel dysprosium(III) crown ether texaphyrin

    Energy Technology Data Exchange (ETDEWEB)

    Sessler, J.L.; Mody, T.D. (Texas Univ., Austin, TX (United States). Dept. of Chemistry); Ramasamy, R.; Sherry, A.D. (Texas Univ., Dallas, TX (United States))

    1992-05-01

    The synthesis and characterization of a novel dysprosium(III) crown-ether texaphyrin (Dy(BCTxp)){sup 2+} is reported. This complex was designed to serve as a ditopic chelate for both dysprosium(III) and sodium cations. {sup 23}Sodium NMR spectroscopic studies indicates that titration of Na{sup +} with increasing concentrations of (Dy(BCTxp)){sup 2+} results in a shift toward higher frequency and gives a net hyperfine shift of 0.86 ppm. Sodium complexation is taking place into the crown subunit in (Dy(BCTxp)){sup 2+} and the degree of complexation is not reduced substantially by the positive charge on the dysprosium(III) portion of this binucleating system.

  3. Selective growth of gold onto copper indium sulfide selenide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Witt, Elena; Parisi, Juergen; Kolny-Olesiak, Joanna [Oldenburg Univ. (Germany). Inst. of Physics, Energy and Semiconductor Research

    2013-05-15

    Hybrid nanostructures are interesting materials for numerous applications in chemistry, physics, and biology, due to their novel properties and multiple functionalities. Here, we present a synthesis of metal-semiconductor hybrid nanostructures composed of nontoxic I-III-VI semiconductor nanoparticles and gold. Copper indium sulfide selenide (CuInSSe) nanocrystals with zinc blende structure and trigonal pyramidal shape, capped with dodecanethiol, serve as an original semiconductor part of a new hybrid nanostructure. Metallic gold nanocrystals selectively grow onto vertexes of these CuInSSe pyramids. The hybrid nanostructures were studied by transmission electron microscopy, energy dispersive X-ray analysis, X-ray diffraction, and UV-Vis-absorption spectroscopy, which allowed us conclusions about their growth mechanism. Hybrid nanocrystals are generated by replacement of a sacrificial domain in the CuInSSe part. At the same time, small selenium nanocrystals form that stay attached to the remaining CuInSSe/Au particles. Additionally, we compare the synthesis and properties of CuInSSe-based hybrid nanostructures with those of copper indium disulfide (CuInS{sub 2}). CuInS{sub 2}/Au nanostructures grow by a different mechanism (surface growth) and do not show any selectivity. (orig.)

  4. Synthesis and stability of hydrogen selenide compounds at high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Pace, Edward J.; Binns, Jack; Alvarez, Miriam Pena; Dalladay-Simpson, Philip; Gregoryanz, Eugene; Howie, Ross T. (Edinburgh); (CHPSTAR- China)

    2017-11-14

    The observation of high-temperature superconductivity in hydride sulfide (H2S) at high pressures has generated considerable interest in compressed hydrogen-rich compounds. High-pressure hydrogen selenide (H2Se) has also been predicted to be superconducting at high temperatures; however, its behaviour and stability upon compression remains unknown. In this study, we synthesize H2Se in situ from elemental Se and molecular H2 at pressures of 0.4 GPa and temperatures of 473 K. On compression at 300 K, we observe the high-pressure solid phase sequence (I-I'-IV) of H2Se through Raman spectroscopy and x-ray diffraction measurements, before dissociation into its constituent elements. Through the compression of H2Se in H2 media, we also observe the formation of a host-guest structure, (H2Se)2H2, which is stable at the same conditions as H2Se, with respect to decomposition. These measurements show that the behaviour of H2Se is remarkably similar to that of H2S and provides further understanding of the hydrogen chalcogenides under pressure.

  5. Dysprosium disilicide nanostructures on silicon(001) studied by scanning tunneling microscopy and transmission electron microscopy

    International Nuclear Information System (INIS)

    Ye Gangfeng; Nogami, Jun; Crimp, Martin A.

    2006-01-01

    The microstructure of self-assembled dysprosium silicide nanostructures on silicon(001) has been studied by scanning tunneling microscopy and transmission electron microscopy. The studies focused on nanostructures that involve multiple atomic layers of the silicide. Cross-sectional high resolution transmission electron microscopy images and fast Fourier transform analysis showed that both hexagonal and orthorhombic/tetragonal silicide phases were present. Both the magnitude and the anisotropy of lattice mismatch between the silicide and the substrate play roles in the morphology and epitaxial growth of the nanostructures formed

  6. Major conformations of the ligand skeleton of a tetranuclear dysprosium (3) tartrate complex

    International Nuclear Information System (INIS)

    Chevela, V.V.; Semenov, V.Eh.; Bezryadin, S.G.; Savitskaya, T.V.; Kolesar, I.R.; Matveev, S.N.; Shamov, G.A.

    1999-01-01

    By the molecular mechanics method (MIND program, stoichiometry was studied and basic conformations of ligand frame of dysprosium (3) tetranuclear complex bis-(d-tartrato) bis-(l-tartrato)tetradysprosiate (3) - anion Dy 4 (d-L) 2 (l-L) 2 4- (1) (d-H 4 L = d-tartaric acid, l-H 4 L = l - tartaric acid) were revealed. It is shown that theoretically calculated mP τ constants for so-called compact conformations of 1, where tartratoligands are in gosh conformation, agree with experimentally obtained constant of paramagnetic birefringence (mP e ) of complex 1 [ru

  7. Incinerator carryover tests with dysprosium as a stand-in for plutonium

    International Nuclear Information System (INIS)

    Hooker, R.L.

    1981-11-01

    A full-scale (5 kg/h) incinerator is being tested with nonradioactive feed materials which simulate SRP-generator combustible transuranic wastes. The incinerator is two-stage and is designed to provide relatively quiescent conditions in the primary chamber where the ash is formed. This feature should minimize entrainment of Pu-bearing particles into the off-gas system. A series of runs have been completed in which incinerator feed was spiked with dysprosium to simulate Pu. Carryover of Dy into the off-gas system was found to be low (about 1/4%). 4 figures, 3 tables

  8. Incorporation of dysprosium ions into PbTiO3 ferroelectric ceramic system

    Directory of Open Access Journals (Sweden)

    A. Peláiz-Barranco

    2015-03-01

    Full Text Available A structural analysis concerning the incorporation of dysprosium into A- and/or B-sites of the lead titanate is shown. The two "boundary" refinements are presented, i.e., Dy2+ substitutes for Pb2+ (Dy3+ substitutes for Ti4+ and Dy3+ substitutes for Pb2+ (Dy3+ substitutes for Ti4+. The results offer quantitative information about the incorporation into both crystallographic sites. The increase of Dy3+ fraction into B-site provides the increase of the Ti4+ atomic displacement along the [001] direction and the tetragonal distortion.

  9. Assessment of fibrous insulation materials for the selenide isotope generator system

    International Nuclear Information System (INIS)

    Wei, G.C; Tennery, V.J.

    1977-11-01

    Fibrous insulations for use in the converter and the heat source of the radioisotope-powered, selenide element, thermoelectric generator (selenide isotope generator) are assessed. The most recent system design and material selection basis is presented. Several fibrous insulation materials which have the potential for use as load-bearing or nonload-bearing thermal insulations are reviewed, and thermophysical properties supplied by manufacturers or published in the literature are presented. Potential problems with the application of fibrous insulations in the selenide isotope generator are as follows: compatibility with graphite, the thermoelectric elements, and the isolation hot frame; devitrification, grain growth, and sintering with an accompanying degradation of insulation quality; impurity diffusion from the insulation to adjoining structures; outgassing and storage of fibrous materials. Areas in which thermophysical data or quantitative information on the insulation and structural stability is lacking are identified

  10. Ammonia-free chemical bath method for deposition of microcrystalline cadmium selenide films

    International Nuclear Information System (INIS)

    Lokhande, C.D.; Lee, Eun-Ho; Jung, Kwang-Deog; Joo, Oh-Shim

    2005-01-01

    Chemical deposition of cadmium selenide (CdSe) films has been carried out from alkaline aqueous solution containing Cd 2+ and Se 2- ions. In general, the alkaline pH of the CdSe deposition bath has been adjusted by addition of liquid ammonia. However, the use of ammonia in large-scale chemical deposition method represents an environmental problem due to its volatility and toxicity. The volatility of ammonia changes the pH of deposition bath and results into irreproducible film properties. In the present paper, ammonia-free and weak alkaline (pH < 9.0) chemical method for cadmium selenide film has been developed. The cadmium selenide films are microcrystalline (grain size 0.5-0.7 μm) with hexagonal crystal structure. These films are photoactive and therefore, useful in photo conversion of light into electrical power

  11. Metal Selenides as Efficient Counter Electrodes for Dye-Sensitized Solar Cells.

    Science.gov (United States)

    Jin, Zhitong; Zhang, Meirong; Wang, Min; Feng, Chuanqi; Wang, Zhong-Sheng

    2017-04-18

    Solar energy is the most abundant renewable energy available to the earth and can meet the energy needs of humankind, but efficient conversion of solar energy to electricity is an urgent issue of scientific research. As the third-generation photovoltaic technology, dye-sensitized solar cells (DSSCs) have gained great attention since the landmark efficiency of ∼7% reported by O'Regan and Grätzel. The most attractive features of DSSCs include low cost, simple manufacturing processes, medium-purity materials, and theoretically high power conversion efficiencies. As one of the key materials in DSSCs, the counter electrode (CE) plays a crucial role in completing the electric circuit by catalyzing the reduction of the oxidized state to the reduced state for a redox couple (e.g., I 3 - /I - ) in the electrolyte at the CE-electrolyte interface. To lower the cost caused by the typically used Pt CE, which restricts the large-scale application because of its low reserves and high price, great effort has been made to develop new CE materials alternative to Pt. A lot of Pt-free electrocatalysts, such as carbon materials, inorganic compounds, conductive polymers, and their composites with good electrocatalytic activity, have been applied as CEs in DSSCs in the past years. Metal selenides have been widely used as electrocatalysts for the oxygen reduction reaction and light-harvesting materials for solar cells. Our group first expanded their applications to the DSSC field by using in situ-grown Co 0.85 Se nanosheet and Ni 0.85 Se nanoparticle films as CEs. This finding has inspired extensive studies on developing new metal selenides in order to seek more efficient CE materials for low-cost DSSCs, and a lot of meaningful results have been achieved in the past years. In this Account, we summarize recent advances in binary and mutinary metal selenides applied as CEs in DSSCs. The synthetic methods for metal selenides with various morphologies and stoichiometric ratios and

  12. Dosimetric properties of dysprosium doped calcium magnesium borate glass subjected to Co-60 gamma ray

    Energy Technology Data Exchange (ETDEWEB)

    Omar, R. S., E-mail: ratnasuffhiyanni@gmail.com; Wagiran, H., E-mail: husin@utm.my; Saeed, M. A. [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 Johor Bahru (Malaysia)

    2016-01-22

    Thermoluminescence (TL) dosimetric properties of dysprosium doped calcium magnesium borate (CMB:Dy) glass are presented. This study is deemed to understand the application of calcium as the modifier in magnesium borate glass with the presence of dysprosium as the activator to be performed as TL dosimeter (TLD). The study provides fundamental knowledge of a glass system that may lead to perform new TL glass dosimetry application in future research. Calcium magnesium borate glass systems of (70-y) B{sub 2}O{sub 3} − 20 CaO – 10 MgO-(y) Dy{sub 2}O{sub 3} with 0.05  mol % ≤ y ≤ 0.7  mol % of dyprosium were prepared by melt-quenching technique. The amorphous structure and TL properties of the prepared samples were determined using powder X-ray diffraction (XRD) and TL reader; model Harshaw 4500 respectively. The samples were irradiated to Co-60 gamma source at a dose of 50 Gy. Dosimetric properties such as annealing procedure, time temperature profile (TTP) setting, optimization of Dy{sub 2}O{sub 3} concentration of 0.5 mol % were determined for thermoluminescence dosimeter (TLD) reader used.

  13. Treatment of rheumatoid synovitis of the knee with intraarticular injection of dysprosium 165-ferric hydroxide macroaggregates

    International Nuclear Information System (INIS)

    Sledge, C.B.; Zuckerman, J.D.; Zalutsky, M.R.

    1986-01-01

    One hundred eight knees of 93 patients with seropositive rheumatoid arthritis and persistent synovitis of the knee were treated with an intraarticular injection of 270 mCi of dysprosium 165 bound to ferric hydroxide macroaggregate. Leakage of radioactivity from the injected joint was minimal. Mean leakage to the venous blood 3 hours after injection was 0.11% of the injected dose; this corresponds to a mean whole body dose of 0.2 rads. Mean leakage to the liver 24 hours after injection was 0.64% of the injected dose; this corresponds to a mean liver dose of 3.2 rads. In 7 additional patients examined, there was negligible or near negligible activity found in the draining inguinal lymph nodes. One-year followup was possible for 74 knees (63 patients). Sixty-one percent of the knees had good results, 23% had fair results, and 16% had poor results. There was a direct correlation between the radiographic stage and response to treatment. In knees with stage I radiographic changes, 72% showed good results; 93% showed improvement. In knees with stage II changes, 59% showed good results; 81% showed improvement. These preliminary results indicate that dysprosium 165-ferric hydroxide macroaggregate is an effective agent for radiation synovectomy. The low leakage rates observed offer a definite advantage over agents previously used

  14. Dual responsive dysprosium-doped hydroxyapatite particles and toxicity reduction after functionalization with folic and glucuronic acids

    Energy Technology Data Exchange (ETDEWEB)

    Sánchez Lafarga, Ana Karen; Pacheco Moisés, Fermín P. [Departamento de Química, Universidad de Guadalajara, Marcelino García Barragán 1421, C.P. 44430, Guadalajara, Jalisco (Mexico); Gurinov, Andrey [Research Resources Center for Magnetic Resonance, Saint Petersburg State University, Universitetskij pr. 26, 198504 St. Petersburg (Russian Federation); Ortiz, Genaro Gabriel [Laboratorio Desarrollo-Envejecimiento, Enfermedades Neurodegenerativas, Centro de Investigación Biomédica de Occidente (CIBO), Instituto Mexicano de Seguro Social (IMSS), Guadalajara, Jalisco (Mexico); Carbajal Arízaga, Gregorio Guadalupe, E-mail: gregoriocarbajal@yahoo.com.mx [Departamento de Química, Universidad de Guadalajara, Marcelino García Barragán 1421, C.P. 44430, Guadalajara, Jalisco (Mexico)

    2015-03-01

    The development of probes for biomedical applications demands materials with low toxicity levels besides fluorescence or magnetic properties to be detected by confocal microscopes or MRI resonators. Several drug delivery systems or other biomedical materials prepared with hydroxyapatite have been proposed, however, toxicity effects might arise when the size of particles is nanometric. In this study, hydroxyapatite functionalized with glucuronic or folic acids presented lower oxidative stress, measured from lipoperoxides and nitric oxide indicators in rats than pure hydroxyapatite. In separated experiments, hydroxyapatite was doped with dysprosium cations by coprecipitation producing a single crystal phase with fluorescent properties easily visualized by confocal microscopy when excited at 488 nm. These particles also presented the ability to modify the proton relaxation time in T1 maps collected by magnetic resonance imaging. These modified hydroxyapatite nanoparticles could be candidates to design bimodal probes with low toxicity. - Highlights: • Hydroxyapatite functionalized with glucuronic acid reduced oxidative stress in rats. • Functionalization with folic acid reduced oxidative stress in rats. • Dysprosium doping does not affect the crystalline structure of hydroxyapatite. • Dysprosium doped particles are visible in fluorescent microscope. • Dysprosium doped particles act as MRI contrast agents.

  15. Kinetic stability of the dysprosium(3) complex with tetraazaporphine in acetic acid-water and acetic acid-methanol mixtures

    International Nuclear Information System (INIS)

    Khelevina, O.G.; Vojnov, A.A.

    1999-01-01

    Water-soluble dysprosium tetraazaporphine with acetylacetonate-ion as extraligand is synthesized for the first time. Its kinetic stability in acetic acid solutions is investigated. It is shown that the complex is dissociated with formation of free tetraazaporphine. Kinetic parameters of dissociation reaction are determined [ru

  16. Dual responsive dysprosium-doped hydroxyapatite particles and toxicity reduction after functionalization with folic and glucuronic acids

    International Nuclear Information System (INIS)

    Sánchez Lafarga, Ana Karen; Pacheco Moisés, Fermín P.; Gurinov, Andrey; Ortiz, Genaro Gabriel; Carbajal Arízaga, Gregorio Guadalupe

    2015-01-01

    The development of probes for biomedical applications demands materials with low toxicity levels besides fluorescence or magnetic properties to be detected by confocal microscopes or MRI resonators. Several drug delivery systems or other biomedical materials prepared with hydroxyapatite have been proposed, however, toxicity effects might arise when the size of particles is nanometric. In this study, hydroxyapatite functionalized with glucuronic or folic acids presented lower oxidative stress, measured from lipoperoxides and nitric oxide indicators in rats than pure hydroxyapatite. In separated experiments, hydroxyapatite was doped with dysprosium cations by coprecipitation producing a single crystal phase with fluorescent properties easily visualized by confocal microscopy when excited at 488 nm. These particles also presented the ability to modify the proton relaxation time in T1 maps collected by magnetic resonance imaging. These modified hydroxyapatite nanoparticles could be candidates to design bimodal probes with low toxicity. - Highlights: • Hydroxyapatite functionalized with glucuronic acid reduced oxidative stress in rats. • Functionalization with folic acid reduced oxidative stress in rats. • Dysprosium doping does not affect the crystalline structure of hydroxyapatite. • Dysprosium doped particles are visible in fluorescent microscope. • Dysprosium doped particles act as MRI contrast agents

  17. Photoconductivity in reactively evaporated copper indium selenide thin films

    Science.gov (United States)

    Urmila, K. S.; Asokan, T. Namitha; Pradeep, B.; Jacob, Rajani; Philip, Rachel Reena

    2014-01-01

    Copper indium selenide thin films of composition CuInSe2 with thickness of the order of 130 nm are deposited on glass substrate at a temperature of 423 ±5 K and pressure of 10-5 mbar using reactive evaporation, a variant of Gunther's three temperature method with high purity Copper (99.999%), Indium (99.999%) and Selenium (99.99%) as the elemental starting materials. X-ray diffraction (XRD) studies shows that the films are polycrystalline in nature having preferred orientation of grains along the (112) plane. The structural type of the film is found to be tetragonal with particle size of the order of 32 nm. The structural parameters such as lattice constant, particle size, dislocation density, number of crystallites per unit area and strain in the film are also evaluated. The surface morphology of CuInSe2 films are studied using 2D and 3D atomic force microscopy to estimate the grain size and surface roughness respectively. Analysis of the absorption spectrum of the film recorded using UV-Vis-NIR Spectrophotometer in the wavelength range from 2500 nm to cutoff revealed that the film possess a direct allowed transition with a band gap of 1.05 eV and a high value of absorption coefficient (α) of 106 cm-1 at 570 nm. Photoconductivity at room temperature is measured after illuminating the film with an FSH lamp (82 V, 300 W). Optical absorption studies in conjunction with the good photoconductivity of the prepared p-type CuInSe2 thin films indicate its suitability in photovoltaic applications.

  18. Selenide Mineralization in the Příbram Uranium and Base-Metal District (Czech Republic

    Directory of Open Access Journals (Sweden)

    Pavel Škácha

    2017-06-01

    Full Text Available Selenium mineralization in the Příbram uranium and base-metal district (Central Bohemia, Czech Republic bound to uraninite occurrences in calcite hydrothermal veins is extremely diverse. The selenides antimonselite, athabascaite, bellidoite, berzelianite, brodtkorbite, bukovite, bytízite, cadmoselite, chaméanite, clausthalite, crookesite, dzharkenite, eskebornite, eucairite, ferroselite, giraudite, hakite, klockmannite, naumannite, permingeatite, příbramite, sabatierite, tiemannite, and umangite were found here, including two new mineral phases: Hg-Cu-Sb and Cu-As selenides. Those selenides—and in some cases their sulphidic equivalents—are characterized using wavelength-dispersive spectroscopy, reflected light, powder X-ray diffraction, single crystal X-ray diffraction, Raman spectroscopy, and electron backscatter diffraction. The selenide mineralization in the Příbram uranium district is bound to the border of the carbonate-uraninite and subsequent carbonate-sulphidic stages. Selenides crystallized there at temperatures near 100 °C in the neutral-to-weakly-alkaline environment from solutions with high oxygen fugacity and a high Se2/S2 fugacity ratio.

  19. The bulk modulus of cubic spinel selenides: an experimental and theoretical study

    DEFF Research Database (Denmark)

    Waskowska, A.; Gerward, Leif; Olsen, J.S.

    2009-01-01

    It is argued that mainly the selenium sublattice determines the overall compressibility of the cubic spinel selenides, AB2Se4, and that the bulk modulus for these compounds is about 100GPa. The hypothesis is supported by experiments using high-pressure X-ray diffraction and synchrotron radiation...

  20. A simple and effective approach to the synthesis of alkynyl selenides from terminal alkynes

    Institute of Scientific and Technical Information of China (English)

    Barahman Movassagh; Mozhgan Navidi

    2012-01-01

    Alkynyl selenides were prepared under very mild conditions by reacting terminal alkynes with respective diorganic diselenides in the presence of potassium t-butoxide.The advantages of this protocol include the use of readily available substrates and reagent and good yield of the products.

  1. Diagnostic Genesis Features of Au-Ag Selenide-Telluride Mineralization of Western Java Deposits

    Directory of Open Access Journals (Sweden)

    Euis Tintin Yuningsih

    2016-01-01

    Full Text Available DOI: 10.17014/ijog.3.1.67-76The ore mineralogy of the westernmost part of West Java such as Pongkor, Cibaliung, Cikidang, Cikotok, and Cirotan are characterized by the dominance of silver-arsenic-antimony sulfosalt with silver selenides and rarely tellurides over the argentite, whereas the eastern part of West Java including Arinem and Cineam deposits are dominated by silver-gold tellurides. Mineralogy of Se-type deposits at Pongkor, Cikidang, Cibaliung, Cisungsang, and Cirotan and Te-type deposits at Arinem and Cineam shows their different geochemical characteristics. Mineralogical and geochemical differences can be explained by variation of physico-chemical conditions that existed during gold-silver deposition by applying the phase relation among sulfide, telluride, and selenide mineral association in the deposits. The relative values of ƒSe2(g, ƒTe(g, and ƒS2(g control the actual presence of selenide or telluride minerals within the West Java deposits, which also depend on their concentrations in the hydrothermal fluid. Even though the concentration of selenium in the hydrothermal fluid of Te-type deposits might have been similar or even higher than that in the Se-type, early substitution of selenium in the sulfide minerals prevents its concentration in the hydrothermal fluid to the levels for precipitating selenide minerals. Therefore, early sulfide mineral deposition from reduction fluids will not increase the ƒSe2(g/ƒS2(g ratio to form selenide minerals in Te-type deposits of Arinem and Cineam, other than selenium-bearing sulfide mineral such as Se-bearing galena or Se-bearing pyrargyrite-proustite.

  2. Watt-level dysprosium fiber laser at 315 μm with 73% slope efficiency

    Science.gov (United States)

    Woodward, R. I.; Majewski, M. R.; Bharathan, G.; Hudson, D. D.; Fuerbach, A.; Jackson, S. D.

    2018-04-01

    Rare-earth-doped fiber lasers are emerging as promising high-power mid-infrared sources for the 2.6-3.0 {\\mu}m and 3.3-3.8 {\\mu}m regions based on erbium and holmium ions. The intermediate wavelength range, however, remains vastly underserved, despite prospects for important manufacturing and defense applications. Here, we demonstrate the potential of dysprosium-doped fiber to solve this problem, with a simple in-band pumped grating-stabilized linear cavity generating up to 1.06 W at 3.15 {\\mu}m. A slope efficiency of 73% with respect to launched power (77% relative to absorbed power) is achieved: the highest value for any mid-infrared fiber laser to date, to the best of our knowledge. Opportunities for further power and efficiency scaling are also discussed.

  3. Proton NMR relaxivity of blood samples in the presence of some gadolinium and dysprosium compounds

    International Nuclear Information System (INIS)

    Coroiu, I.; Darabont, Al.; Bogdan, M.

    1999-01-01

    The use of some new compounds in MRI tissue and blood characterisation based on nuclear spin relaxation time measurements cannot be sustained until the molecular sources of these variations are understood. Tissues and blood are complex molecular systems with complex NMR properties. A better comprehension of the molecular basis of relaxation offers the possibility to predict the changes expected for a given pathology. The purpose of this contribution is to evidence the different relaxation characteristics of some gadolinium and dysprosium compounds in the presence and absence of the blood and to give a possible explanation about the molecular processes that cause occurrence of changes. Some gadolinium and dysprosium compounds such as: Gd-CIT (gadolinium citrate), Dy-DTPA (DTPA-diethylenetriamine pentaacetic acid), iron oxide - gadolinium oxide (or dysprosium oxide)- dextran complexes were prepared. The longitudinal T 1 -1 and transverse T 2 -1 'relaxation rates' measurements have been carried out as a function of molar concentrations. All measurements have been made at room temperature (about 25 deg.C) and the proton Larmor frequency ν o = 90 MHz. The pulsed NMR spectrometer utilised was a commercial Bruker SXP4/100 spectrometer. Transverse relaxation rate measurements have been made using the Carr-Purcell method, while longitudinal relaxation rate measurements using the inversion recovery pulse sequence, 180 angle-τ-90 angle. The accuracy was about 2-3% for the longitudinal relaxation rates and about 5-7% for the transverse relaxation rates. R 1 and R 2 relaxivities, in mM -1 s -1 were determined from the least square determination of the slopes of plots 1/T 1,2 versus compound molar concentration, using at least five independent measurements at several concentrations between 0 and 2 mM. Increased R 2 relaxivity observed for dysprosium compounds in the blood presence can be explained by PRE effect. The largest gain in R 2 relaxivity seems to imply a noncovalent

  4. Investigation on rare earth magnets recycling by organophosphoric extractant encapsulated polymeric beads for separation of dysprosium

    International Nuclear Information System (INIS)

    Yadav, Kartikey K.; Singh, D.K.; Kain, V.

    2017-01-01

    Rare earth elements (REEs) are a basic requirement of the electronics and new industries including green technology. In the present work an organophosphoric extractant encapsulating polyethersulfone (PES) beads has been developed and employed for dysprosium (Dy) separation from aqueous stream. Polyethersulfonic beads encapsulating PC88A were prepared by phase inversion method. During the synthesis of the beads, preparatory parameters were also optimized to obtain best suited beads which were subsequently characterized for their encapsulation capacity and micro structural investigation. The results obtained in the present investigation suggested that PES/PVAJPC88A composite beads could be used for separation of rare earths from aqueous medium obtained from the solubilisation of magnetic scrap materials

  5. Design and validation of a photon insensitive multidetector neutron spectrometer based on Dysprosium activation foils

    International Nuclear Information System (INIS)

    Gómez-Ros, J.M.; Bedogni, R.; Palermo, I.; Esposito, A.; Delgado, A.; Angelone, M.; Pillon, M.

    2011-01-01

    This communication describes a photon insensitive passive neutron spectrometer consisting of Dysprosium (Dy) activation foils located along three perpendicular axes within a single moderating polyethylene sphere. The Monte Carlo code MCNPX 2.6 was used to optimize the spatial arrangement of the detectors and to derive the spectrometer response matrix. Nearly isotropic response in terms of neutron fluence for energies up to 20 MeV was obtained by combining the readings of the detectors located at the same radius value. The spectrometer was calibrated using a previously characterized 14 MeV neutron beam produced in the ENEA Frascati Neutron Generator (FNG). The overall uncertainty of the spectrometer response matrix at 14 MeV, assessed on the basis of this experiment, was ±3%.

  6. Influence of modifiers on the separation of dysprosium from neodymium using organophosphorus acid derivates

    Energy Technology Data Exchange (ETDEWEB)

    Elwert, Tobias; Schwarz, Sabrina; Goldmann, Daniel [TU Clausthal, Clausthal-Zellerfeld (Germany). Lehrstuhl fuer Rohstoffaufbereitung und Recycling

    2016-01-15

    The aim of this study was to investigate the applicability of three organophosphorus acid derivates (D2EHPA, EHEHPA and Cyanex 572) for the separation of terbium and dysprosium from praseodymium and neodymium from NdFeB magnets in chloride solution. A special focus was put on the effect of phase modifiers. The investigations revealed that all extractants show in general a similar extraction behavior but the extraction is shifted to higher pH values in the order D2EHPA < EHEHPA < Cyanex 572. Therefore, and due to higher realizable loadings, EHEHPA and Cyanex 572 are more suitable for the investigated separation problem than D2EHPA. Whereas EHEHPA requires 1-decanol as phase modifier, Cyanex 572 can be employed without modifier addition.

  7. Automated spectrofluorimetric determinations of terbium and dysprosium in rare earth mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Lyle, S.J.; Za' tar, N. (Kent Univ., Canterbury (UK))

    1983-12-01

    Several methods involving the use of water-soluble binary and ternary complexes have been proposed for the spectrofluorimetric determination based on terbium(III) emission at 545 nm. These are terbium(III) with (A) ethylenediamine-N,N'-bis(o-hydroxyphenylacetic acid), (B) o-hydroxyphenyliminodiacetic acid, (C) EDTA + 5-sulphosalicylic acid, (D) EDTA + 1,2-dihydroxybenzene-3,5-disulphonic acid disodium salt (Tiron), and (E) iminodiacetic acid (IDA) + Tiron. Two of the reagent mixtures (D and E) can also be used for the fluorimetric determination of dysprosium(III) at 582 nm. A comparison has been made of these methods in order to select the most satisfactory procedure with respect to selectivity, sensitivity and suitability for adaption to automatic operation. Results are given and discussed.

  8. Spectrographic determination of dysprosium in doped crystals of calcium sulfate used for dosimetric material

    International Nuclear Information System (INIS)

    Grigoletto, T.; Lordello, A.R.

    1984-01-01

    A spectrographic method is described for the quantitative determination of dysprosium in doped crystals of calcium sulphate. The consequences of the changes in some parameters of the excitation conditions, such as arc current, electrode type and total or partial burning of sample, in the analytical results are discussed. Matrix effects are investigated. Variations in the intensity of the spectral lines are verified by recording the spectrum in distinct photographic plates. The role of internal standard in analytical reproducibility and in counterbalance of the variations in the arc current and in the weight of sample is studied. Accuracy is estimated by comparative analysis of two calcium sulphate samples by X-Ray Fluorescence, Neutron Activation and Inductive Coupled Plasma Emission Spectroscopy. (M.A.C.) [pt

  9. Use of dispersive liquid-liquid microextraction for simultaneous preconcentration of samarium, europium, gadolinium and dysprosium

    International Nuclear Information System (INIS)

    Mallah, M.H.; Atomic Energy Organization of Iran, Tehran; Shemirani, F.; Ghannadi Maragheh, M.

    2008-01-01

    A new preconcentration method of dispersive liquid-liquid microextraction (DLLME) was developed for simultaneous preconcentration of samarium, europium, gadolinium and dysprosium. DLLME technique was successfully used as a sample preparation method. In this preconcentration method, an appropriate mixture of extraction solvent, disperser solvent was injected rapidly into an aqueous solution containing Sm, Eu, Gd and Dy after complex formation using chelating reagent of the 1-(2-pyridylazo)-2-naphthol (PAN). After phase separation, 0.5 mL of the settled phase containing enriched analytes was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The main factors affected the preconcentration of Sm, Eu, Gd and Dy were extraction and dispersive solvent type and their volume, extraction time, volume of chelating agent (PAN), centrifuge speed and drying temperature of the samples. Under the best operating condition simultaneous preconcentration factors of 80, 100, 103 and 78 were obtained for Sm, Eu, Gd and Dy, respectively. (author)

  10. A model for additive transport in metal halide lamps containing mercury and dysprosium tri-iodide

    International Nuclear Information System (INIS)

    Beks, M L; Haverlag, M; Mullen, J J A M van der

    2008-01-01

    The distribution of additives in a metal halide lamp is examined through numerical modelling. A model for a lamp containing sodium iodide additives has been modified to study a discharge containing dysprosium tri-iodide salts. To study the complex chemistry the method of Gibbs minimization is used to decide which species have to be taken into account and to fill lookup tables with the chemical composition at different combinations of elemental abundance, lamp pressure and temperature. The results from the model with dysprosium additives were compared with earlier results from the lamp containing sodium additives and a simulation of a pure mercury lamp. It was found that radial segregation creates the conditions required for axial segregation. Radial segregation occurs due to the unequal diffusion of atoms and molecules. Under the right conditions convection currents in the lamp can cause axial demixing. These conditions depend on the ratio of axial convection and radial diffusion as expressed by the Peclet number. At a Peclet number of unity axial segregation is most pronounced. At low Peclet numbers radial segregation is at its worst, while axial segregation is not present. At large Peclet numbers the discharge becomes homogeneously mixed. The degree of axial segregation at a Peclet number of unity depends on the temperature at which the additive under consideration fully dissociates. If the molecules dissociate very close to the walls no molecules are transported by the convective currents in the lamp, and hence axial segregation is limited. If they dissociate further away from the walls in the area where the downward convective currents are strongest, more axial segregation is observed

  11. Electrochemical behaviour of dysprosium in the eutectic LiCl-KCl at W and Al electrodes

    International Nuclear Information System (INIS)

    Castrillejo, Y.; Bermejo, M.R.; Barrado, A.I.; Pardo, R.; Barrado, E.; Martinez, A.M.

    2005-01-01

    The electrochemical behaviour of DyCl 3 was studied in the eutectic LiCl-KCl at different temperatures. The cathodic reaction can be written:Dy(III)+3e-bar Dy(0)which can be divided in two very close cathodic steps:Dy(III)+1e-bar Dy(II)andDy(II)+2e-bar Dy(0)Transient electrochemical techniques, such as cyclic voltammetry, chronopotentiometry, and chronoamperometry were used in order to study the reaction mechanism and the transport parameters of electroactive species at a tungsten electrode. The results showed that in the eutectic LiCl-KCl, electrocrystallization of dysprosium seems to be the controlling electrochemical step. Chronoamperometric studies indicated instantaneous nucleation of dysprosium with three dimensional growth of the nuclei whatever the applied overpotential.Mass transport towards the electrode is a simple diffusion process, and the diffusion coefficient of the electroactive species, i.e. Dy(III), has been calculated. The validity of the Arrhenius law was also verified by plotting the variation of the logarithm of the diffusion coefficient versus 1/T.In addition, the electrode reactions of the LiCl-KCl-DyCl 3 solutions at an Al wire were also investigated by cyclic voltammetry and open circuit chronopotentiometry. The redox potential of the Dy(III)/Dy couple at the Al electrode was observed at more positive potentials values than those at the inert electrode. This potential shift was thermodynamically analyzed by a lowering of activity of Dy in the metal phase due to the formation of intermetallic compounds

  12. Dysprosium lithium borate glass mircrospheres for radiation synovectomy: The in vitro and in vivo performance evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Di; Yu Jing [Institute of Bioengineering and Information Technology Materials, Center for Advanced Materials and Nano-Biomedicine, Tongji University, Shanghai, 200092 (China); Huang Wenhai, E-mail: whhuang@tongji.edu.cn [Institute of Bioengineering and Information Technology Materials, Center for Advanced Materials and Nano-Biomedicine, Tongji University, Shanghai, 200092 (China); Zhou Nai; Wang Deping [Institute of Bioengineering and Information Technology Materials, Center for Advanced Materials and Nano-Biomedicine, Tongji University, Shanghai, 200092 (China); Yin Wei [Institute of Isotope Research, Sinitic Academy of Atomic Energy, Beijing 102413 (China); Chen Yaqing [The Sixth People' s Hospital, Shanghai 200233 (China)

    2010-08-30

    The radioactive dysprosium lithium borate glass (DyLB) microspheres with different glass compositions were prepared for radiation synovectomy. The biodegradability and biocompatibility of these DyLB microspheres were evaluated in vitro and in vivo. The DyLB microspheres studied in this work were partially biodegradable in a simulated body fluid (SBF), with the final weight loss of the microspheres in the range of 24.6% and 55.0% (wt.%) after 8 days of immersion. The ICP results revealed that the dissolution of lithium significantly decreased from 100% to 53.7% with increasing content of Dy{sub 2}O{sub 3} in the microspheres from 18% to 22% (wt.%, from S-1 to S-3). However, for all of the three samples, nearly all of the dysprosium (> 99.997%, wt.%) remained in the microspheres, in the form of insoluble phosphates and carbonates, which was proved by the SEM and EDX analyses. The degradation of DyLB microspheres in SBF gradually decreased with immersion time and eventually reached equilibrium after 7 days of immersion. Compared to the other two samples, the S-3 sample with the lowest Dy{sup 3+} dissolution (about 0.002%) was considered more secure for clinical application. Furthermore, the S-3 DyLB microspheres exhibited good biocompatibility, since neither tissue damage nor inflammation was observed, after they were implanted in the liver of rat for two weeks. After neutron activation, the radionuclide purity of radioactive S-3 DyLB microspheres was 99.999%, which were suitable for radiation synovectomy.

  13. Photoluminescence study on amino functionalized dysprosium oxide-zinc oxide composite bifunctional nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, Aswathy; Praveen, G.L; Abha, K.; Lekha, G.M [Department of Chemistry, University of Kerala, Kariavattom, Kerala 695581 (India); George, Sony, E-mail: emailtosony@gmail.com [Department of Chemistry, University of Kerala, Kariavattom, Kerala 695581 (India)

    2012-08-15

    An organic dispersion of 9-15 nm size stable dysprosium oxide incorporated zinc oxide nanocomposites exhibiting luminescence in the visible region has been synthesised by a wet chemical precipitation technique at room temperature. Tetraethoxysilane TEOS [(C{sub 2}H{sub 5}O){sub 4}Si], (3-aminopropyl) trimethoxysilane (APTS) and a 1:1 mixture of TEOS-APTS have been used as capping agents to control the particle size as well as to achieve uniform dispersion of composite nanoparticles in methanol medium. X-ray diffractometer (XRD) analysis reveals the formation phase of amino-functionalised colloidal dysprosium oxide incorporated ZnO composite nanoparticles to be of zincite structure. The Transmission Electron Microscopy (TEM) images show that the particles are spheroids in shape, having average crystalline sizes ranging from 9 to 15 nm. The photoluminescence (PL) observed in these composites has been attributed to the presence of near band edge excitonic emission and existence of defect centres. The time correlated single photon counting studies of the composite nanoparticles exhibited three decay pathways. The enhanced PL emission intensity of solid state fluorescence spectra of samples is attributed to the absence of vibrational relaxation process. - Highlights: Black-Right-Pointing-Pointer Nano-composites are synthesised using a one step wet chemical precipitation method. Black-Right-Pointing-Pointer A significant fluorescence life time of 8.25 ns is obtained for the nano-composite. Black-Right-Pointing-Pointer Nano-composite particles exhibited pale yellow fluorescence rather than blue. Black-Right-Pointing-Pointer Vibrational cascade free enhanced fluorescence is obtained for the dry sample.

  14. Simultaneous determination of dysprosium, holmium and erbium in high purity rare earth oxides by second order derivative spectrophotometry

    International Nuclear Information System (INIS)

    Anbu, M.; Prasada Rao, T.; Iyer, C. S. P.; Damodaran, A. D.

    1996-01-01

    High purity individual rare earth oxides are increasingly used as major components in lasers (Y 2 O 3 ), phosphors (YVO 3 , Eu 2 O 3 ), magnetic bubble memory films (Gd 2 O 3 ) and refractive-index lenses and fibre optics (La 2 O 3 ). The determination of individual lanthanides in high purity rare earth oxides is a more important and difficult task. This paper reports the utilization of higher order derivative spectrophotometry for the simultaneous determination of dysprosium, holmium and erbium in high purity rare earth oxides. The developed procedure is simple, reliable and allows the determination of 0.001 to 0.2% of dysprosium, holmium and erbium in several rare earth. (author). 9 refs, 2 figs, 2 tabs

  15. Mixed (phthalocyaninato)(Schiff-base) di-dysprosium sandwich complexes. Effect of magnetic coupling on the SMM behavior.

    Science.gov (United States)

    Wang, Hailong; Liu, Chenxi; Liu, Tao; Zeng, Suyuan; Cao, Wei; Ma, Qi; Duan, Chunying; Dou, Jianmin; Jiang, Jianzhuang

    2013-11-21

    Reaction between Schiff-base ligand and half-sandwich complex M(Pc)(acac) led to the isolation of new sandwich-type mixed (phthalocyaninato)(Schiff-base) di-lanthanide compounds M2(Pc)2(L)H2O (M = Dy, Gd) (1, 2) [H2Pc = metal free phthalocyanine, Hacac = acetylacetone, H2L = N,N'-bis(3-methyloxysalicylidene)benzene-1,2-diamine] with the triple-decker molecular structure clearly revealed by single crystal X-ray diffraction analysis. For the comparative studies, sandwich triple-decker analogues with pure Schiff-base ligand M2(L)3H2O (M = Dy, Gd) (3, 4) were also prepared. Dynamic magnetic measurement result reveals the single-molecule magnet (SMM) nature of the di-dysprosium derivative 1, while the static magnetic investigation over both pure and the diamagnetic diluted samples of this compound discloses the interionic ferromagnetic coupling between the two dysprosium ions, which in turn effectively suppresses the QTM and enhances the energy barrier of this SMM. Nevertheless, comparative studies over the static magnetic properties of the di-dysprosium triple-decker complexes 1 and 3 indicate the stronger magnetic coupling between the two lanthanide ions in mixed (phthalocyaninato)(Schiff-base) species than in the pure Schiff-base triple-decker analogue, suggesting the special coordination sphere around the dysprosium ions in the former compound over the latter one on the more intense inter-ionic ferromagnetic coupling. As a very small step towards understanding the structure-property relationship, the present result will be surely helpful for the design and synthesis of the multinuclear lanthanide-based SMMs with good properties.

  16. Hydrothermal synthesis and characterization of sea urchin-like nickel and cobalt selenides nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xiaohe [Department of Inorganic Materials, Central South University, Changsha, Hunan 410083 (China) and School of Metallurgical Science and Engineering, Central South University, Changsha, Hunan 410083 (China)]. E-mail: liuxh@mail.csu.edu.cn; Zhang Ning [Department of Inorganic Materials, Central South University, Changsha, Hunan 410083 (China); Yi Ran [Department of Inorganic Materials, Central South University, Changsha, Hunan 410083 (China); Qiu Guanzhou [Department of Inorganic Materials, Central South University, Changsha, Hunan 410083 (China); Yan Aiguo [Department of Inorganic Materials, Central South University, Changsha, Hunan 410083 (China); Wu Hongyi [Department of Inorganic Materials, Central South University, Changsha, Hunan 410083 (China); Meng Dapeng [Department of Inorganic Materials, Central South University, Changsha, Hunan 410083 (China); Tang, Motang [School of Metallurgical Science and Engineering, Central South University, Changsha, Hunan 410083 (China)

    2007-05-25

    Sea urchin-like nanorod-based nickel and cobalt selenides nanocrystals have been selective synthesized via a hydrothermal reduction route in which hydrated nickel chloride and hydrated cobalt chloride were employed to supply Ni and Co source and aqueous hydrazine (N{sub 2}H{sub 4}.H{sub 2}O) was used as reducing agent. The composition, morphology, and structure of final products could be easily controlled by adjusting the molar ratios of reactants and process parameters such as hydrothermal time. The morphology and phase structure of the final products have been investigated by X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. The probable formation mechanism of the sea urchin-like nanorod-based nickel and cobalt selenides nanocrystals was discussed on the basis of the experimental results.

  17. Electronic band structure and optical properties of antimony selenide under pressure

    Energy Technology Data Exchange (ETDEWEB)

    Abhijit, B.K.; Jayaraman, Aditya; Molli, Muralikrishna, E-mail: muralikrishnamolli@sssihl.edu.in [Department of Physics, Sri Sathya Sai Institute of Higher Learning, Prasanthinilayam, 515 134 (India)

    2016-05-23

    In this work we present the optical properties of Antimony Selenide (Sb{sub 2}Se{sub 3}) under ambient conditions and under pressure of 9.2 GPa obtained using first principles calculations. We investigated the electronic band structure using the FP-LAPW method within the sphere of the density functional theory. Optical properties like refractive index, absorption coefficient and optical conductivity are calculated using the WIEN2k code.

  18. Peroxidase-like activity of nanocrystalline cobalt selenide and its application for uric acid detection

    Directory of Open Access Journals (Sweden)

    Zhuang QQ

    2017-04-01

    Full Text Available Quan-Quan Zhuang,1 Zhi-Hang Lin,1 Yan-Cheng Jiang,1 Hao-Hua Deng,2 Shao-Bin He,1,3 Li-Ting Su,4 Xiao-Qiong Shi,2 Wei Chen2 1Department of Pharmacy, Affiliated Quanzhou First Hospital of Fujian Medical University, Quanzhou, 2Department of Pharmaceutical Analysis, School of Pharmacy, Fujian Medical University, Fuzhou, 3Department of Pharmacy, Quanzhou Infectious Disease Hospital, 4Department of Pharmaceutical Analysis, Quanzhou Medical College, Quanzhou, People’s Republic of China Abstract: Dendrite-like cobalt selenide nanostructures were synthesized from cobalt and selenium powder precursors by a solvothermal method in anhydrous ethylenediamine. The as-prepared nanocrystalline cobalt selenide was found to possess peroxidase-like activity that could catalyze the reaction of peroxidase substrates in the presence of H2O2. A spectrophotometric method for uric acid (UA determination was developed based on the nanocrystalline cobalt selenide-catalyzed coupling reaction between N-ethyl-N-(3-sulfopropyl-3-methylaniline sodium salt and 4-aminoantipyrine (4-AAP in the presence of H2O2. Under optimum conditions, the absorbance was proportional to the concentration of UA over the range of 2.0–40 µM with a detection limit of 0.5 µM. The applicability of the proposed method has been validated by determination of UA in human serum samples with satisfactory results. Keywords: enzyme mimics, cobalt selenide, peroxidase-like activity, uric acid, human serum

  19. Determination of dimethyl selenide and dimethyl sulphide compounds causing off-flavours in bottled mineral waters.

    Science.gov (United States)

    Guadayol, Marta; Cortina, Montserrat; Guadayol, Josep M; Caixach, Josep

    2016-04-01

    Sales of bottled drinking water have shown a large growth during the last two decades due to the general belief that this kind of water is healthier, its flavour is better and its consumption risk is lower than that of tap water. Due to the previous points, consumers are more demanding with bottled mineral water, especially when dealing with its organoleptic properties, like taste and odour. This work studies the compounds that can generate obnoxious smells, and that consumers have described like swampy, rotten eggs, sulphurous, cooked vegetable or cabbage. Closed loop stripping analysis (CLSA) has been used as a pre-concentration method for the analysis of off-flavour compounds in water followed by identification and quantification by means of GC-MS. Several bottled water with the aforementioned smells showed the presence of volatile dimethyl selenides and dimethyl sulphides, whose concentrations ranged, respectively, from 4 to 20 ng/L and from 1 to 63 ng/L. The low odour threshold concentrations (OTCs) of both organic selenide and sulphide derivatives prove that several objectionable odours in bottled waters arise from them. Microbial loads inherent to water sources, along with some critical conditions in water processing, could contribute to the formation of these compounds. There are few studies about volatile organic compounds in bottled drinking water and, at the best of our knowledge, this is the first study reporting the presence of dimethyl selenides and dimethyl sulphides causing odour problems in bottled waters. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Theory of two-magnon Raman scattering in alkaline iron selenide superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.S. [Department of Physics, Yanshan University, Qinhuangdao 006004 (China); Department of Physics, National Taiwan Normal University, Taipei 11677, Taiwan (China); Zhang, A.M. [Department of Physics, Renmin University of China, Beijing 100872 (China); Xu, T.F. [Department of Physics, Yanshan University, Qinhuangdao 006004 (China); Wu, W.C., E-mail: wu@phy.ntnu.edu.tw [Department of Physics, National Taiwan Normal University, Taipei 11677, Taiwan (China)

    2014-11-15

    Highlights: • Two-magnon Raman scattering is theoretically studied for alkaline iron selenides. • Underlying spin interactions of the √(5)×√(5) AF superstructure are investigated in details. • Optimal set of exchange parameters is revealed when fitting to experiments. - Abstract: Motivated by the recent experiment of two-magnon Raman scattering in alkaline iron selenide superconductors (Zhang et al., 2012), we investigate in details the underlying spin interactions of the √(5)×√(5) antiferromagnetic superstructure. Based on the linear spin wave approximation, the Fleury-London (FL) two-magnon Raman cross-sections are calculated. By comparing theoretical results with the Raman data in both A{sub g} and B{sub g} channels, an optimal set of exchange parameters which are consistent with the fitting to the neutron scattering data are obtained. It reveals that the experimentally observed broad and asymmetric peaks around 1600 cm{sup −1} are dominantly originated from quasiparticle excitations in two nearly degenerate magnon bands in the (0,±π) and (±π,0) directions. The result thus supports that the magnetic properties in alkaline iron selenide AFe{sub 1.6+x}Se{sub 6} superconductors can be basically described by the quantum spin model with up to third nearest-neighbor exchange couplings.

  1. Evaluating United States and world consumption of neodymium, dysprosium, terbium, and praseodymium in final products

    Science.gov (United States)

    Hart, Matthew

    This paper develops scenarios of future rare-earth-magnet metal (neodymium, dysprosium, terbium, and praseodymium) consumption in the permanent magnets used in wind turbines and hybrid electric vehicles. The scenarios start with naive base-case scenarios for growth in wind-turbine and hybrid-electric-vehicle sales over the period 2011 to 2020, using historical data for each good. These naive scenarios assume that future growth follows time trends in historical data and does not depend on any exogenous variable. Specifically, growth of each technological market follows historical time trends, and the amount of rare earths used per unit of technology remains fixed. The chosen reference year is 2010. Implied consumptions of the rare earth magnet metals are calculated from these scenarios. Assumptions are made for the material composition of permanent magnets, the market share of permanent-magnet wind turbines and vehicles, and magnet weight per unit of technology. Different scenarios estimate how changes in factors like the material composition of magnets, growth of the economy, and the price of a substitute could affect future consumption. Each scenario presents a different method for reducing rare earth consumption and could be interpreted as potential policy choices. In 2010, the consumption (metric tons, rare-earth-oxide equivalent) of each rare-earth-magnet metal was as follows. Total neodymium consumption in the world for both technologies was 995 tons; dysprosium consumption was 133 tons; terbium consumption was 50 tons; praseodymium consumption was zero tons. The base scenario for wind turbines shows there could be strong, exponential growth in the global wind turbine market. New U.S. sales of hybrid vehicles would decline (in line with the current economic recession) while non-U.S. sales increase through 2020. There would be an overall increase in the total amount of magnetic rare earths consumed in the world. Total consumption of each rare earth in the short

  2. Spectrographic determination of dysprosium dopant in calcium sulphate used as dosimetric material

    International Nuclear Information System (INIS)

    Grigoletto, T.

    1982-01-01

    A spectrographic method is described for the quantitative determination of dysprosium in doped crystals of calcium sulphate. The consequences of the changes in some parameters of the excitation conditions, such as arc current, electrode type and total or partial burning of sample, in the analytical results are discussed. Matrix effects are investigated by comparison among analytical curves obtained from three different methods of standard preparations. Variations in the intensity of the spectral lines are verificated by recording the spectrum in distinct photographic plates (SA-1). The role of internal standard in analytical reproducibility and in counterbalance of the variations in the arc current and in the weight of sample are studied. The great similarity in excitation behavior of many of the rare earths is used to provide a high degree of internal standardization. Precision studies show a standard deviation of about + - 2,4 percent by use of lanthanum as an internal standard. Accuracy is estimate by comparative analysis of two calcium sulphate samples by X-Rays Fluorescence, Neutron Activation and Inductive Coupled Plasma (ICP) Emission Spectroscopy. (Author) [pt

  3. Combustion of gadolinium and dysprosium chelates as a cellular integrity marker in MR imaging

    International Nuclear Information System (INIS)

    Ericsson, A.; Bach-Gansmo, T.; Niklasson, F.; Hemmingsson, A.

    1995-01-01

    A combination of gadolinium (Gd) and dysprosium (Dy) chelates was investigated as a potential marker of cell-membrane integrity by means of a double-contrast effect in MR imaging. Blood samples with varying hematocrit (Hct) levels containing intact or lysed cells were used as model systems. With intact cells, the agents were assumed to be distributed solely extracellularly and the highest Hct studied (69%) was assumed to mimic the ratio of extracellular to intracellular water in tissue. The combined effect on image intensity of Gd (in a concentration corresponding to 0.2 mmol/kg b.w. in humans) and Dy (0.6 mmol/kg b.w.) applied simultaneously was a marked difference in signal intensity between samples with intact and lysed cells in both the T1- and T2-weighted spin-echo images with a corresponding increase in the contrast-to-noise ratio. This was the result of a T1 reduction caused by Gd with a negligible Dy susceptibility effect in areas with lysed cells. On the other hand, the Dy susceptibility effect (i.e. reduced apparent T2) dominated in areas with intact cells. Thus, the combination of Gd and Dy may serve as a marker of cell-membrane integrity in MR examinations. (orig.)

  4. Isolation of {sup 163}Ho from dysprosium target material by HPLC for neutrino mass measurements

    Energy Technology Data Exchange (ETDEWEB)

    Mocko, Veronika; Taylor, Wayne A.; Nortier, Francois M.; Engle, Jonathan W.; Pollington, Anthony D.; Kunde, Gerd J.; Rabin, Michael W.; Birnbaum, Eva R. [Los Alamos National Laboratory, Los Alamos, NM (United States). Chemistry Div.; Barnhart, Todd E.; Nickles, Robert J. [Univ. Wisconsinn, Madison, WI (United States). Dept. of Medical Physics

    2015-07-01

    The rare earth isotope {sup 163}Ho is of interest for neutrino mass measurements. This report describes the isolation of {sup 163}Ho from a proton-irradiated dysprosium target and its purification. A Dy metal target was irradiated with 16 MeV protons for 10 h. After target dissolution, {sup 163}Ho was separated from the bulk Dy via cation-exchange high performance liquid chromatography using 70 mmol dm{sup -3} α-hydroxyisobutyric acid as the mobile phase. Subsequent purification of the collected Ho fraction was performed to remove the α-hydroxyisobutyrate chelating agent and to concentrate the Ho in a low ionic strength aqueous matrix. The final solution was characterized by MC-ICP-MS to determine the {sup 163}Ho/{sup 165}Ho ratio, {sup 163}Ho and the residual Dy content. The HPLC purification process resulted in a decontamination factor 1.4 x 10{sup 5} for Dy. The isolated Ho fraction contained 24.8 ± 1.3 ng of {sup 163}Ho corresponding to holmium recovery of 72 ± 3%.

  5. Nuclear statistics of dysprosium resonance parameters in the energy range 10 - 1000 eV

    International Nuclear Information System (INIS)

    Shin, S. G.; Kye, Y. U.; Cho, M. H.; Kim, G. N.; Namkung, W.; Lee, M. W.; Kang, Y. R.; Roe, T. I.

    2016-01-01

    A resonance parameter analysis is often performed in the Resolved Resonance Region (RRR) in order to estimate the average level spacing, distribution of the reduced widths and so on. Neutron Capture experiments on dysprosium isotopes were performed at the electron linear accelerator (LINAC) facility of the Rensselear Polytechnic Institute (RPI) in the neutron energy region from 10 eV to 1 keV. The following nuclear statistics of the resonance parameters will be discussed in this paper. The D 0 for 161 Dy and 163 Dy were judged to be constant up to 120.6 and 163.9 eV, respectively. It was assumed that the D 0 of 162 Dy and 164 Dy is constant up to 1000 eV because they have few resonances. The results were compared with the values from Reference 11 as shown in Figure 1. Statistical distributions of reduced neutron were investigated for the three isotopes in the region from 0 to 1000 eV; 161 Dy, 162 Dy, and 163 Dy, but not for 164 Dy because of a few number of resonances. The reduced neutron widths Γ n 0 were divided by the unweighted average reduced neutron width < Γ n 0 > for each isotope. A cumulative distribution of these unitless ratios is compared with the integral of the Porter-Thomas distribution (χ 2 distribution with one degree of freedom). The results agree reasonably with the Porter Thomas distributions.

  6. Self-organized dysprosium-directed alginate hydrogels and its chemical features

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Qianmin [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Gao, Jinwei [Institute for Advanced Materials, Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006 (China); Peng, Huojun [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Wang, Qianming, E-mail: qmwang@scnu.edu.cn [Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Guangzhou Key Laboratory of Materials for Energy Conversion and Storage, Guangzhou 510006 (China)

    2016-09-15

    Rational use of self-organized materials may contribute in developing new structures and devices in practical technology. Synthetic metallo-supramolecular gels are generally designed with transitional metal-directed process. However, the assembly of both lanthanide and sodium alginate in macromolecular systems would find a new way of utilizing its physical properties. The stimuli-responsive molecule (alginate) could firmly form stable hydrogels upon the encapsulation of dysprosium ions. In addition, the immobilization of YVO{sub 4}: Eu{sup 3+} nanoparticle in the soft matrix has been achieved and it has never been explored in the fabrication of phosphor-incorporated luminescent alginate gels. The key feature of the present soft matter is that its red emission could be switched off in the presence of sodium ascorbate and the results may have a tremendous impact on the extension of photophysical application based on soft nanoscale devices. - Highlights: • Dy{sup 3+} can be used for the gelation of the dissolved alginate. • Lanthanide hydrogels could exhibit red emissions under excitations. • Luminescence could be switched “off” in the presence of sodium ascorbate.

  7. Optical properties of zinc borotellurite glass doped with trivalent dysprosium ion

    Science.gov (United States)

    Ami Hazlin, M. N.; Halimah, M. K.; Muhammad, F. D.; Faznny, M. F.

    2017-04-01

    The zinc borotellurite doped with dysprosium oxide glass samples with chemical formula {[(TeO2) 0 . 7(B2O3) 0 . 3 ] 0 . 7(ZnO) 0 . 3 } 1 - x(Dy2O3)x (where x=0.01, 0.02, 0.03, 0.04 and 0.05 M fraction) were prepared by using conventional melt quenching technique. The structural and optical properties of the proposed glass systems were characterized by using X-ray diffraction (XRD) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, and UV-VIS spectroscopy. The amorphous nature of the glass systems is confirmed by using XRD technique. The infrared spectra of the glass systems indicate three obvious absorption bands which are assigned to BO3 and TeO4 vibrational groups. Based on the absorption spectra obtained, the direct and indirect optical band gaps, as well as the Urbach energy were calculated. It is observed that both the direct and indirect optical band gaps increase with the concentration of Dy3+ ions. On the other hand, the Urbach energy is observed to decrease as the concentration of Dy3+ ions increases.

  8. The liquid membrane for extraction of Yttrium and Dysprosium from Acid Nitric

    International Nuclear Information System (INIS)

    Johny, W.S.; Raldi-Artono-Koestoer; Kris-Tri-Basuki; Sudibyo

    1996-01-01

    The determination of surfactant in liquid membrane has been done. The surfactant is span-80 (sorbitol-monooleate), the liquid membrane phase was the organic phase (O), the internal liquid phase (W) with ratio O/W = 1, and surfactant. The organic phase using D 2 EHPA in the kerosene and the internal liquid phase using aqua des or acid nitric. The determination of surfactant with variation of span-80 (0,25 - 2%) in the liquid membrane volume. The speed of stirrer was 3500 rpm in 20 minute. The ratio of liquid membrane phase form and external phase (aqua des or acid nitric) was 1, the speed of stirrer was 350 rpm in 10 minute (permeation process). The liquid phase and the liquid membrane phase was separated and then determinated the volume of liquid membrane, the result of percentage of span-80 was 0,25 % volume. The extraction of yttrium and dysprosium in 2 M HNO 3 was Kd y = 2.945 and Kd D y = 0.019

  9. Morphology-Tuned Synthesis of Nickel Cobalt Selenides as Highly Efficient Pt-Free Counter Electrode Catalysts for Dye-Sensitized Solar Cells.

    Science.gov (United States)

    Qian, Xing; Li, Hongmei; Shao, Li; Jiang, Xiancai; Hou, Linxi

    2016-11-02

    In this work, morphology-tuned ternary nickel cobalt selenides based on different Ni/Co molar ratios have been synthesized via a simple precursor conversion method and used as counter electrode (CE) materials for dye-sensitized solar cells (DSSCs). The experimental facts and mechanism analysis clarified the possible growth process of product. It can be found that the electrochemical performance and structures of ternary nickel cobalt selenides can be optimized by tuning the Ni/Co molar ratio. Benefiting from the unique morphology and tunable composition, among the as-prepared metal selenides, the electrochemical measurements showed that the ternary nickel cobalt selenides exhibited a more superior electrocatalytic activity in comparison with binary Ni and Co selenides. In particular, the three-dimensional dandelion-like Ni 0.33 Co 0.67 Se microspheres delivered much higher power conversion efficiency (9.01%) than that of Pt catalyst (8.30%) under AM 1.5G irradiation.

  10. Custom Coordination Environments for Lanthanoids: Tripodal Ligands Achieve Near-Perfect Octahedral Coordination for Two Dysprosium-Based Molecular Nanomagnets.

    Science.gov (United States)

    Lim, Kwang Soo; Baldoví, José J; Jiang, ShangDa; Koo, Bong Ho; Kang, Dong Won; Lee, Woo Ram; Koh, Eui Kwan; Gaita-Ariño, Alejandro; Coronado, Eugenio; Slota, Michael; Bogani, Lapo; Hong, Chang Seop

    2017-05-01

    Controlling the coordination sphere of lanthanoid complexes is a challenging critical step toward controlling their relaxation properties. Here we present the synthesis of hexacoordinated dysprosium single-molecule magnets, where tripodal ligands achieve a near-perfect octahedral coordination. We perform a complete experimental and theoretical investigation of their magnetic properties, including a full single-crystal magnetic anisotropy analysis. The combination of electrostatic and crystal-field computational tools (SIMPRE and CONDON codes) allows us to explain the static behavior of these systems in detail.

  11. Experimental and theoretical approach on the optical properties of zinc borotellurite glass doped with dysprosium oxide

    Science.gov (United States)

    Halimah, M. K.; Ami Hazlin, M. N.; Muhammad, F. D.

    2018-04-01

    A series of glass samples with chemical formula {[(TeO2)0.7(B2O3)0.3]0.7(ZnO)0.3}1 - x(Dy2O3)x where x = 0.01, 0.02, 0.03, 0.04 and 0.05 M fraction were synthesized through conventional melt-quenching method. The most common way to fabricate a glass material is by fusion of two or more component oxides followed by their quenching. This technique is known as melt-quenching technique. Kaur et al. (2016) [1] highlighted that the melt-quenching method able to enhance the mechanical properties like hardness and flexural strength of the material. The nature of the glass systems is proven to be amorphous based on the XRD pattern. The FTIR spectra of the glass systems confirm the existence of five bands which are assigned for the BO4, BO3, TeO4 and TeO3 vibrational groups. The density of the glass systems is increased with the addition of Dy2O3 while the molar volume is found to be inversely proportional to the density of the proposed glass. The optical properties of the glasses are determined through the absorption spectra obtained from the UV-VIS spectrophotometer. From the absorption spectra, the indirect and direct optical band gaps and the Urbach energy are found to be inversely proportional to each other. As the molar fraction of the Dy2O3 increased, the optical band gaps are observed to increase as opposed to the Urbach energy. For this glass system, the values of refractive index, electronic polarizability, oxide ion polarizability and the optical basicity are found to decrease as the addition of the dysprosium oxide is increased. From the emission spectra, two intense blue and yellow emission bands are observed, which correspond to the 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 transitions of Dy3 + ions respectively. The CIE chromaticity coordinates of the zinc borotellurite glass systems are found to be located in the white light region. Generation of white light The generation of the white light can be achieved by using two emission bands which comprise of the yellow

  12. Electrosynthesis of cadmium selenide films from sodium citrate-selenosulphite bath

    International Nuclear Information System (INIS)

    Lokhande, C.D.; Lee, Eun-Ho; Jung, Kwang-Deog; Joo, Oh-Shim

    2005-01-01

    Electrosynthesis of cadmium selenide (CdSe) film has been carried out from deposition bath containing sodium selenosulphite, along with cadmium complexed with sodium citrate under potentiostatic deposition condition on titanium substrates. The pH of deposition bath was weakly basic (< 9.0). The CdSe films up to 3.0 μm were deposited. The X-ray diffraction (XRD) studies revealed that the CdSe films are microcrystalline with increased grain size after annealing. The scanning electron microscopy showed that the films are porous with cauliflower-like morphology. The photelectrochemical characterization showed that the CdSe films are photoactive

  13. Enhanced Manifold of States Achieved in Heterostructures of Iron Selenide and Boron-Doped Graphene

    Directory of Open Access Journals (Sweden)

    Valentina Cantatore

    2017-10-01

    Full Text Available Enhanced superconductivity is sought by employing heterostructures composed of boron-doped graphene and iron selenide. Build-up of a composite manifold of near-degenerate noninteracting states formed by coupling top-of-valence-band states of FeSe to bottom-of-conduction-band states of boron-doped graphene is demonstrated. Intra- and intersubsystem excitons are explored by means of density functional theory in order to articulate a normal state from which superconductivity may emerge. The results are discussed in the context of electron correlation in general and multi-band superconductivity in particular.

  14. Selenide mineralization in the Příbram uranium and base-metal district (Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Škácha, P.; Sejkora, J.; Plášil, Jakub

    2017-01-01

    Roč. 7, č. 6 (2017), s. 1-56, č. článku 91. ISSN 2075-163X R&D Projects: GA MŠk LO1603 EU Projects: European Commission(XE) CZ.2.16/3.1.00/24510 Institutional support: RVO:68378271 Keywords : selenides * chemical composition * crystal structure * wavelength-dispersive spectroscopy * X-ray diffraction * Příbram Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 2.088, year: 2016

  15. Enhanced performance of hybrid solar cells using longer arms of quantum cadmium selenide tetrapods

    KAUST Repository

    Lee, Kyu-Sung

    2011-12-01

    We demonstrate that enhanced device performance of hybrid solar cells based on tetrapod (TP)-shaped cadmium selenide (CdSe) nanoparticles and conjugated polymer of poly (3-hexylthiophene) (P3HT) can be obtained by using longer armed tetrapods which aids in better spatial connectivity, thus decreasing charge hopping events which lead to better charge transport. Longer tetrapods with 10 nm arm length lead to improved power conversion efficiency of 1.12% compared to 0.80% of device having 5 nm short-armed tetrapods:P3HT photoactive blends.

  16. Enhanced performance of hybrid solar cells using longer arms of quantum cadmium selenide tetrapods

    KAUST Repository

    Lee, Kyu-Sung; Kim, Inho; Gullapalli, Sravani; Wong, Michael S.; Jabbour, Ghassan E.

    2011-01-01

    We demonstrate that enhanced device performance of hybrid solar cells based on tetrapod (TP)-shaped cadmium selenide (CdSe) nanoparticles and conjugated polymer of poly (3-hexylthiophene) (P3HT) can be obtained by using longer armed tetrapods which aids in better spatial connectivity, thus decreasing charge hopping events which lead to better charge transport. Longer tetrapods with 10 nm arm length lead to improved power conversion efficiency of 1.12% compared to 0.80% of device having 5 nm short-armed tetrapods:P3HT photoactive blends.

  17. Textured dysprosium and gadolinium poles for high-field, short-period hybrid undulators

    International Nuclear Information System (INIS)

    Murokh, Alex; Solovyov, Vyacheslav; Agustsson, Ron; O'Shea, Finn H.; Chubar, Oleg; Chen, Yung; Grandsaert, Thomas

    2014-01-01

    We discuss the feasibility of enhancement of the gap field in a short-period hybrid undulator by using pole inserts with the saturation inductance B s , over that of iron, 2 T. Dysprosium metal, with the saturation inductance of 3.4 T below 90 K, and Gadolinium with B s =2.7 T, appear as good candidates as the optimized pole material. However, due to the high magnetic anisotropy of Dy, such a high level of magnetization can only be realized when the external field lies in the basal plane. This implies that the pole has to be single-crystalline or highly textured. Considering that growing large, >10mm, Dy single crystals is difficult, we propose secondary recrystallization as a method to induce the required texture in thin Dy and Gd foils. The textured foils can be stacked to produce pole inserts of the desired geometry and orientation. Results of small-scale processing and magnetic measurements of thin (20–60 μ) foils provide evidence that the required texture quality can be achieved by a relatively simple sequence of heat-treatments and cold rolling. The advantage of textured Dy and Gd poles is demonstrated in a several period test undulator. -- Highlights: • Textured rare-earth materials for use as undulator pole materials. • We measure the development of texture in Dy and Gd. • We compare the rare-earth materials with high saturation steel in undulators. • Thin sheets of Dy and Gd materials perform similar to single crystals

  18. Electrocatalytic approach for the efficiency increase of electrolytic hydrogen production: Proof-of-concept using platinum-dysprosium alloys

    International Nuclear Information System (INIS)

    Santos, D.M.F.; Šljukić, B.; Sequeira, C.A.C.; Macciò, D.; Saccone, A.; Figueiredo, J.L.

    2013-01-01

    Development of electrocatalytic materials for the hydrogen evolution reaction (HER) is attempted with the aim of reducing the water electrolysis overpotential and increasing its efficiency. Using linear scan voltammetry measurements of the hydrogen discharge enables evaluation of the electrocatalytic activity for the HER of platinum–dysprosium (Pt–Dy) intermetallic alloy electrodes of different compositions. Understanding of materials electrocatalytic performance is based on determination of several crucial kinetic parameters, including the Tafel coefficients, b, charge transfer coefficients, α, exchange current densities, j 0 , and activation energies, E a . Influence of temperature on HER is investigated by performing studies at temperatures ranging from 25 °C to 85 °C. The effect of the Dy amount in the efficiency of the HER on the Pt–Dy alloys is analysed. Results demonstrate that Dy can substantially increase the electrocatalytic activity of the Pt alloys, in comparison to the single Pt electrode. Efforts are made to correlate the microstructure of the alloys with their performance towards the HER. - Highlights: ► Development of electrocatalysts to increase efficiency of electrolytic hydrogen production. ► Synthesis and evaluation of composition and morphology of platinum–dysprosium (Pt–Dy) alloys. ► Hydrogen evolution reaction on Pt–Dy alloys electrodes studied using linear scan voltammetry in alkaline medium. ► Pt–Dy alloy with equiatomic composition enhances kinetics of hydrogen discharge compared to single Pt

  19. The application of x-ray spectrometry to isotopic-source activation analysis of dysprosium and holmium

    International Nuclear Information System (INIS)

    Pillay, A.E.; Mboweni, R.C.M.

    1990-01-01

    A novel aspect of activation analysis is described for the determination of dysprosium and holmium at low concentrations. The method involves the measurement of K x-rays from radionuclides produced by thermal neutron activation using a 1 mg 252 Cf source. The basis for elemental selection depends largely on the demand for analysis and on the existence of favourable nuclear properties for the production of a practicable x-ray yield. A full appraisal of the analytical potential of the method is presented with particular emphasis on its application to geological matrices. The sensitivity was optimised by employing a detector that was particularly effective at photon energies below 150 keV. Analytical conditions are demonstrated for the elements of interest over a wide range of concentrations in small powdered samples. The investigation formed the basis of a feasibility study to establish if the application could be developed for the routine off-line determination of dysprosium and holmium using an isotopic-neutron source. (author)

  20. Reduction of titanocene dichloride with dysprosium: access to a stable titanocene(ii) equivalent for phosphite-free Takeda carbonyl olefination.

    Science.gov (United States)

    Bousrez, G; Déchamps, I; Vasse, J-L; Jaroschik, F

    2015-05-28

    The reduction of titanocene dichloride with dysprosium yields a new titanocene(ii) equivalent without the need for further stabilising ligands. This reagent can be employed in combination with dithioacetals for the olefination of different carbonyl groups and allows for a simplified all-in-one procedure.

  1. Polycrystalline thin films of antimony selenide via chemical bath deposition and post deposition treatments

    International Nuclear Information System (INIS)

    Rodriguez-Lazcano, Y.; Pena, Yolanda; Nair, M.T.S.; Nair, P.K.

    2005-01-01

    We report a method for obtaining thin films of polycrystalline antimony selenide via chemical bath deposition followed by heating the thin films at 573 K in selenium vapor. The thin films deposited from chemical baths containing one or more soluble complexes of antimony, and selenosulfate initially did not show X-ray diffraction (XRD) patterns corresponding to crystalline antimony selenide. Composition of the films, studied by energy dispersive X-ray analyses indicated selenium deficiency. Heating these films in presence of selenium vapor at 573 K under nitrogen (2000 mTorr) resulted in an enrichment of Se in the films. XRD peaks of such films matched Sb 2 Se 3 . Evaluation of band gap from optical spectra of such films shows absorption due to indirect transition occurring in the range of 1-1.2 eV. The films are photosensitive, with dark conductivity of about 2 x 10 -8 (Ω cm) -1 and photoconductivity, about 10 -6 (Ω cm) -1 under tungsten halogen lamp illumination with intensity of 700 W m -2 . An estimate for the mobility life time product for the film is 4 x 10 -9 cm 2 V -1

  2. From zinc selenate to zinc selenide nano structures synthesized by reduction process

    International Nuclear Information System (INIS)

    Hutagalung, S.D.; Eng, S.T.; Ahmad, Z.A.; Ishak Mat; Yussof Wahab

    2009-01-01

    One-dimensional nano structure materials are very attractive because of their electronic and optical properties depending on their size. It is well known that properties of material can be tuned by reducing size to nano scale because at the small sizes, that they behave differently with its bulk materials and the band gap will control by the size. The tunability of the band gap makes nano structured materials useful for many applications. As one of the wide band gaps semiconductor compounds, zinc selenide (ZnSe) nano structures (nanoparticles, nano wires, nano rods) have received much attention for the application in optoelectronic devices, such as blue laser diode, light emitting diodes, solar cells and IR optical windows. In this study, ZnSe nano structures have been synthesized by reduction process of zinc selenate using hydrazine hydrate (N 2 H 4 .2H 2 O). The reductive agent of hydrazine hydrate was added to the starting materials of zinc selenate were heat treated at 500 degree Celsius for 1 hour under argon flow to form one-dimensional nano structures. The SEM and TEM images show the formation of nano composite-like structure, which some small nano bar and nano pellets stick to the rod. The x-ray diffraction and elemental composition analysis confirm the formation of mixture zinc oxide and zinc selenide phases. (author)

  3. PROPERTIES AND OPTICAL APPLICATION OF POLYCRYSTALLINE ZINC SELENIDE OBTAINED BY PHYSICAL VAPOR DEPOSITION

    Directory of Open Access Journals (Sweden)

    A. A. Dunaev

    2015-05-01

    Full Text Available Findings on production technology, mechanical and optical properties of polycrystalline zinc selenide are presented. The combination of its physicochemical properties provides wide application of ZnSe in IR optics. Production technology is based on the method of physical vapor deposition on a heated substrate (Physical Vapor Deposition - PVD. The structural features and heterogeneity of elemental composition for the growth surfaces of ZnSe polycrystalline blanks were investigated using CAMEBAX X-ray micro-analyzer. Characteristic pyramid-shaped crystallites were recorded for all growth surfaces. The measurements of the ratio for major elements concentrations show their compliance with the stoichiometry of the ZnSe compounds. Birefringence, optical homogeneity, thermal conductivity, mechanical and optical properties were measured. It is established that regardless of polycrystalline condensate columnar and texturing, the optical material is photomechanically isotropic and homogeneous. The actual performance of parts made of polycrystalline optical zinc selenide in the thermal spectral ranges from 3 to 5 μm and from 8 to 14 μm and in the CO2 laser processing plants with a power density of 500 W/cm2 is shown. The developed technology gives the possibility to produce polycrystalline optical material on an industrial scale.

  4. Chemical Potential Tuning and Enhancement of Thermoelectric Properties in Indium Selenides.

    Science.gov (United States)

    Rhyee, Jong-Soo; Kim, Jin Hee

    2015-03-20

    Researchers have long been searching for the materials to enhance thermoelectric performance in terms of nano scale approach in order to realize phonon-glass-electron-crystal and quantum confinement effects. Peierls distortion can be a pathway to enhance thermoelectric figure-of-merit ZT by employing natural nano-wire-like electronic and thermal transport. The phonon-softening known as Kohn anomaly, and Peierls lattice distortion decrease phonon energy and increase phonon scattering, respectively, and, as a result, they lower thermal conductivity. The quasi-one-dimensional electrical transport from anisotropic band structure ensures high Seebeck coefficient in Indium Selenide. The routes for high ZT materials development of In₄Se₃ - δ are discussed from quasi-one-dimensional property and electronic band structure calculation to materials synthesis, crystal growth, and their thermoelectric properties investigations. The thermoelectric properties of In₄Se₃ - δ can be enhanced by electron doping, as suggested from the Boltzmann transport calculation. Regarding the enhancement of chemical potential, the chlorine doped In₄Se₃ - δ Cl 0.03 compound exhibits high ZT over a wide temperature range and shows state-of-the-art thermoelectric performance of ZT = 1.53 at 450 °C as an n -type material. It was proven that multiple elements doping can enhance chemical potential further. Here, we discuss the recent progress on the enhancement of thermoelectric properties in Indium Selenides by increasing chemical potential.

  5. Compatibility of Pt-3008 with selected components of the selenide isotope generator system

    International Nuclear Information System (INIS)

    Keiser, J.R.

    1979-04-01

    The first in a new generation of radioisotopic thermoelectric generators being built by Teledyne Energy Systems and designated the Selenide Isotope Generator has thermoelectric materials that can be degraded by reaction with O 2 , H 2 O, CO, and other gases. Consequently, for at least the first ground demonstration system a protective xenon atmosphere will be maintained over the thermoelectrics. The high-temperature portion of the atmosphere-retaining structure will be fabricated from the alloy Pt-3008 (Pt--30 wt % Rh--8 wt % W), which was developed at Oak Ridge National Laboratory. For this application Pt-3008 must be compatible with the various insulations and thermoelectric materials. A study of the compatibility of Pt-3008 with these materials and showed that Pt-3008 was embrittled after exposure to some of the insulations that were not adequately outgassed and by one of the thermoelectric materials (Cu 2 Se) in some of the isothermal tests. It is believed that Pt-3008 will be compatible with the Selenide Isotope Generator materials when they are well outgassed and under the temperature gradient conditions of the operating system

  6. Chemical Potential Tuning and Enhancement of Thermoelectric Properties in Indium Selenides

    Directory of Open Access Journals (Sweden)

    Jong-Soo Rhyee

    2015-03-01

    Full Text Available Researchers have long been searching for the materials to enhance thermoelectric performance in terms of nano scale approach in order to realize phonon-glass-electron-crystal and quantum confinement effects. Peierls distortion can be a pathway to enhance thermoelectric figure-of-merit ZT by employing natural nano-wire-like electronic and thermal transport. The phonon-softening known as Kohn anomaly, and Peierls lattice distortion decrease phonon energy and increase phonon scattering, respectively, and, as a result, they lower thermal conductivity. The quasi-one-dimensional electrical transport from anisotropic band structure ensures high Seebeck coefficient in Indium Selenide. The routes for high ZT materials development of In4Se3−δ are discussed from quasi-one-dimensional property and electronic band structure calculation to materials synthesis, crystal growth, and their thermoelectric properties investigations. The thermoelectric properties of In4Se3−δ can be enhanced by electron doping, as suggested from the Boltzmann transport calculation. Regarding the enhancement of chemical potential, the chlorine doped In4Se3−δCl0.03 compound exhibits high ZT over a wide temperature range and shows state-of-the-art thermoelectric performance of ZT = 1.53 at 450 °C as an n-type material. It was proven that multiple elements doping can enhance chemical potential further. Here, we discuss the recent progress on the enhancement of thermoelectric properties in Indium Selenides by increasing chemical potential.

  7. Two-step synthesis of silver selenide semiconductor with a linear magnetoresistance effect

    International Nuclear Information System (INIS)

    Yang, Fengxia; Xiong, Shuangtao; Liu, Fengxian; Han, Chong; Zhang, Duanming; Xia, Zhengcai

    2012-01-01

    A two-step synthesis method for polycrystalline β-silver selenide (β-Ag 2 Se) was developed. In the first step, nanopowder was prepared using a chemical conversion method at room temperature. In the second step, the nanopowder was compressed and then the bulk Ag 2 Se was fabricated by the solid-state sintering process. The crystalline phase and morphology were examined. The results showed that β-Ag 2 Se was fast fabricated at room temperature. The dense polycrystalline Ag-rich Ag 2 Se was synthesized successfully at 450 °C for 0.5 h under Argon flow. For the polycrystalline, the electronic properties and transverse magnetoresistance (TMR) in a pulsed magnetic field were investigated. The samples displayed n-type semiconducting behaviors and a critical temperature with a broaden temperature range of 140–150 K. Also, it presented a positive and nearly linear dependence on magnetic field H at H ≥ H c (crossover field) ranging from 2 to 20 T. Moreover, the linear dependence of TMR at strong field was non-saturating up to 35 T. Combining with the observation of morphology, it is thought that this unusual TMR effect was caused by slightly excess Ag. This new synthesis method provided a potential route to synthesize nonstoichiometric silver selenide. (paper)

  8. Asymmetric supercapacitors with metal-like ternary selenides and porous graphene electrodes

    KAUST Repository

    Xia, Chuan

    2016-04-14

    Asymmetric supercapacitors provide a promising approach to fabricate capacitive energy storage devices with high energy and power densities. In this work, asymmetric supercapacitors with excellent performance have been fabricated using ternary (Ni, Co)0.85Se on carbon fabric as bind-free positive electrode and porous free-standing graphene films as negative electrode. Owing to their metal-like conductivity (~1.67×106 S m−1), significant electrochemical activity, and superhydrophilic nature, our nanostructured ternary nickel cobalt selenides result in a much higher areal capacitance (2.33 F cm−2 at 4 mA cm−2), better rate performance and cycling stability than their binary selenide equivalents, and other ternary oxides and chalcogenides. Those hybrid supercapacitors can afford impressive areal capacitance and stack capacitance of 529.3 mF cm−2 and 6330 mF cm−3 at 1 mA cm−2, respectively. More impressively, our optimized asymmetric device operating at 1.8 V delivers a very high stack energy density of 2.85 mWh cm−3 at a stack power density of 10.76 mW cm−3, as well as 85% capacitance retention after 10,000 continuous charge-discharge cycles. Even at a high stack power density of 1173 mW cm−3, this device still deliveries a stack energy density of 1.19 mWh cm−3, superior to most of the reported supercapacitors.

  9. Transition metal oxide nanopowder and ionic liquid: an efficient system for the synthesis of diorganyl selenides, selenocysteine and derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Narayanaperumal, Senthil; Gul, Kashif; Kawasoko, Cristiane Y.; Singh, Devender; Dornelles, Luciano; Rodrigues, Oscar E.D. [Universidade Federal de Santa Maria (UFSC), RS (Brazil). Dept. de Quimica. LabSelen-NanoBio; Braga, Antonio L. [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. de Quimica. LabSelen

    2010-07-01

    We have developed an efficient method for the synthesis of diorganyl selenides and {beta}-seleno amines using Zn, catalytic amounts of ZnO nanopowder, as a catalyst and ionic liquid as a recyclable solvent. This ZnO/ionic liquid system shows high efficiency in catalyzing these transformations with the formation of the desired products in high yields. (author)

  10. Acute dysprosium toxicity to Daphnia pulex and Hyalella azteca and development of the biotic ligand approach

    Energy Technology Data Exchange (ETDEWEB)

    Vukov, Oliver, E-mail: vuko3930@mylaurier.ca [Biology Department, Wilfrid Laurier University, Waterloo, Ontario N2L 3C5 (Canada); Smith, D. Scott [Chemistry Department, Wilfrid Laurier University, Waterloo, Ontario N2L 3C5 (Canada); McGeer, James C. [Biology Department, Wilfrid Laurier University, Waterloo, Ontario N2L 3C5 (Canada)

    2016-01-15

    The toxicological understanding of rare earth elements (REEs) in the aquatic environment is very limited but of increasing concern. The objective of this research is to compare the toxicological effect of the REE dysprosium to the freshwater invertebrates Daphnia pulex and Hyalella azteca and in the more sensitive organism, understand the toxicity modifying influence of Ca, Na, Mg, pH and dissolved organic matter (DOM). Standard methods (Environment Canada) were followed for testing and culture in media of intermediate hardness (60 mg CaCO{sub 3} mg/L) at pH 7.8 with Ca at 0.5, Na 0.5, Mg 0.125 (mM) and 23 °C. Acute toxicity tests were done with <24 h old neonates for 48 h in the case of D. pulex and with 2–9 days old offspring for 96 h tests with Hyalella. The potential protective effect of cationic competition was tested with Ca (0.5–2.0 mM), Na (0.5–2.0 mM) and Mg (0.125–0.5 mM). The effect of pH (6.5–8.0) and Suwannee River DOM complexation (at dissolved organic carbon (DOC) concentrations of 9 and 13 mg C/L) were evaluated. Dissolved Dy concentrations were lower than total (unfiltered) indicating precipitation, particularly at higher concentrations. Acute toxicity of Dy to H. azteca and D. pulex revealed Hyalella to be 1.4 times more sensitive than Daphnia. Additions of Ca and Na but not Mg provided significant protection against Dy toxicity to Hyalella. Similarly, low pH was associated with reduction in toxicity. Exposures which were pH buffered with and without MOPS were significantly different and indicated that MOPS enhanced Dy toxicity. DOM also mitigated Dy toxicity. Biotic ligand based parameters (Log K values) were calculated based on free ion relationships as determined by geochemical equilibrium modeling software (WHAM ver. 7.02). The log K value for Dy{sup 3+} toxicity to Hyalella was 7.75 while the protective influence of Ca and Na were 3.95 and 4.10, respectively. This study contributes data towards the development of site specific

  11. Synthesis and characterization of phosphors based on calcium and magnesium silicates doped with europium and dysprosium

    International Nuclear Information System (INIS)

    Misso, Agatha Matos

    2016-01-01

    Ca and Mg silicates based phosphors were prepared by sol-gel method combined with the molten salts process. The gel of silica was obtained from Na 2 SiO 3 solution by using europium, dysprosium, calcium and magnesium chloride solutions. Therefore, those chlorides were homogeneously dispersed into the gel. The obtained gel was dried and heat treated to 900° C for 1h to allow the fusion of the present salts. Then it was water washed until negative test for Cl - , and dried. The reduction of the europium to Eu 2+ was performed under atmosphere of 5% of H 2 and 95% of Ar to 900° C for 3h, to reach CaMgSi 2 O 6 :Eu 2+ and CaMgSi 2 O 6 :Eu 2+ :Dy 3+ phosphors. Diopside was identified as main crystalline phase and quartz, as secondary phase from XRD (X-ray diffraction) patterns. SEM (scanning electron microscopy) micrographs, of the samples showed needles, spheres, leaves and rods of particles and agglomerates. Thermal analysis (TGA-DTGA) curves revealed that the crystallization temperature of CaMgSi 2 O 6 :Eu 2+ lies around 765° C. Photoluminescence spectroscopy of the phosphors was studied based on interconfigurational 4f N → 4f N-1 5d transition of Eu 2+ ion. The spectra of excitation showed 4f N → 4f N-1 5d transition of Eu 2+ ion broad band, related to the ligand to metal charge transfer transition (LMCT) O 2- (2p) → Eu 3+ in the 250 nm region, when the emission is monitored at 583,5 nm. It also presents the 4f ↔ 4f transitions of Eu 3+ ion bands, showing the 7 F 0 → 5 L 6 transition at 393 nm. From emission spectra with excitation monitored at 393 nm, it can be observed fine peaks between 570 and 750 nm which are characteristics of 5 D 0 → 7 F J (J = 0 - 5) transition of Eu 3+ ion, indicating that the Eu 3+ ion occupies a site with center of inversion. Finally, the obtained results indicate that the developed method is suitable to synthesize CaMgSi 2 O 6 :Eu 2+ and CaMgSi 2 O 6 :Eu 2+ :Dy 3+ phosphors, as it has been proposed. (author)

  12. Luminescence properties of dysprosium doped calcium magnesium silicate phosphor by solid state reaction method

    Energy Technology Data Exchange (ETDEWEB)

    Sahu, Ishwar Prasad, E-mail: ishwarprasad1986@gmail.com [School of Studies in Physics & Astrophysics, Pt. Ravishankar Shukla University, Raipur, C.G. 492010 (India); Chandrakar, Priya; Baghel, R.N.; Bisen, D.P.; Brahme, Nameeta [School of Studies in Physics & Astrophysics, Pt. Ravishankar Shukla University, Raipur, C.G. 492010 (India); Tamrakar, Raunak Kumar [Department of Applied Physics, Bhilai Institute of Technology, Durg, C.G. 491001 (India)

    2015-11-15

    Dysprosium doped calcium magnesium silicate (CaMgSi{sub 2}O{sub 6}:Dy{sup 3+}) white light emitting phosphor was synthesized by solid state reaction process. The crystal structure of sintered phosphor was monoclinic structure with space group C2/c. Chemical composition of the sintered CaMgSi{sub 2}O{sub 6}:Dy{sup 3+} phosphor was confirmed by EDX. The prepared CaMgSi{sub 2}O{sub 6}:Dy{sup 3+} phosphor was excited from 352 nm and their corresponding emission spectra were recorded at blue (470 nm), yellow (570 nm) and red (675 nm) line due to the {sup 4}F{sub 9/2} → {sup 6}H{sub 15/2}, {sup 4}F{sub 9/2} → {sup 6}H{sub 13/2}, {sup 4}F{sub 9/2} → {sup 6}H{sub 11/2} transitions of Dy{sup 3+} ions. The combination of these three emissions constituted as white light confirmed by the Commission Internationale de L'Eclairage (CIE) chromatic coordinate diagram. The possible mechanism of the white light emitting long lasting CaMgSi{sub 2}O{sub 6}:Dy{sup 3+} phosphor was also investigated. Investigation on afterglow property show that phosphor held fast and slow decay process. The peak of mechanoluminescence (ML) intensity increases linearly with increasing impact velocity of the moving piston. Thus the present investigation indicates that the local piezoelectricity-induced electron bombardment model is responsible to produce ML in prepared CaMgSi{sub 2}O{sub 6}:Dy{sup 3+} phosphor. - Highlights: • The crystal structure of CaMgSi{sub 2}O{sub 6}:Dy{sup 3+} phosphor is consistent with standard monoclinic structure. • CIE coordinates of CaMgSi{sub 2}O{sub 6}:Dy{sup 3+} phosphor is suitable as white light emitting phosphor. • The local piezoelectricity-induced electron bombardment model is responsible to produce ML in CaMgSi{sub 2}O{sub 6}:Dy{sup 3+} phosphor.

  13. An ICP AES method for determination of dysprosium and terbium in high purity yttrium oxide

    International Nuclear Information System (INIS)

    Rupawate, V.H.; Hareendran, K.N.; Roy, S.B.

    2011-01-01

    High purity yttrium finds interesting application in astronavigation, luminescence, nuclear energy and metallurgical industries. Most of these applications require yttrium oxide of highest purity. Consequently there is a need for production of high purity yttrium oxide. Separation and purification of yttrium from other rare earths is a challenging task due to their close chemical properties. Liquid-liquid extraction and ion exchange have been widely used in the production of yttrium oxide of highest purity. Determination of impurities, especially other rare earths, in ppm level is required for process development and chemical characterization of the high purity Y 2 O 3 . Many methods have been described in literature. However since the advent of ICP AES much work in this area has been carried out by this technique. This paper describes the work done for determination of dysprosium (Dy) and terbium (Tb) in yttrium oxide using a high resolution sequential ICP AES. Emission spectra of rare earth elements are very complex and due to this complexity it is important to select spectral interference free analyte lines for determination of rare earths in rare earth matrix. For the determination of Dy and Tb in Y 2 O 3 , sensitive lines of Dy and Tb are selected from the instrument wavelength table and spectral interference free emission lines for the determination is selected by scanning around the selected wavelengths using 5 g/L Y solution and 5 mg/L standard solutions of Dy and Tb prepared in 4% nitric acid. It is found 353.170 nm line of Dy and 350.917 nm line Tb is suitable for quantitative determination. The signal to background ratio increases with increase in matrix concentration, i.e. from 1 to 5 mg/L. The optimum forward power is determined and it is found to be 1100W for Dy and 1000W for Tb. The instrument is calibrated using matrix matched standards containing 5g/L of Y matrix. Samples are dissolved in nitric acid and Y concentration is maintained at 5g/L. Two

  14. Acute dysprosium toxicity to Daphnia pulex and Hyalella azteca and development of the biotic ligand approach

    International Nuclear Information System (INIS)

    Vukov, Oliver; Smith, D. Scott; McGeer, James C.

    2016-01-01

    The toxicological understanding of rare earth elements (REEs) in the aquatic environment is very limited but of increasing concern. The objective of this research is to compare the toxicological effect of the REE dysprosium to the freshwater invertebrates Daphnia pulex and Hyalella azteca and in the more sensitive organism, understand the toxicity modifying influence of Ca, Na, Mg, pH and dissolved organic matter (DOM). Standard methods (Environment Canada) were followed for testing and culture in media of intermediate hardness (60 mg CaCO 3 mg/L) at pH 7.8 with Ca at 0.5, Na 0.5, Mg 0.125 (mM) and 23 °C. Acute toxicity tests were done with <24 h old neonates for 48 h in the case of D. pulex and with 2–9 days old offspring for 96 h tests with Hyalella. The potential protective effect of cationic competition was tested with Ca (0.5–2.0 mM), Na (0.5–2.0 mM) and Mg (0.125–0.5 mM). The effect of pH (6.5–8.0) and Suwannee River DOM complexation (at dissolved organic carbon (DOC) concentrations of 9 and 13 mg C/L) were evaluated. Dissolved Dy concentrations were lower than total (unfiltered) indicating precipitation, particularly at higher concentrations. Acute toxicity of Dy to H. azteca and D. pulex revealed Hyalella to be 1.4 times more sensitive than Daphnia. Additions of Ca and Na but not Mg provided significant protection against Dy toxicity to Hyalella. Similarly, low pH was associated with reduction in toxicity. Exposures which were pH buffered with and without MOPS were significantly different and indicated that MOPS enhanced Dy toxicity. DOM also mitigated Dy toxicity. Biotic ligand based parameters (Log K values) were calculated based on free ion relationships as determined by geochemical equilibrium modeling software (WHAM ver. 7.02). The log K value for Dy 3+ toxicity to Hyalella was 7.75 while the protective influence of Ca and Na were 3.95 and 4.10, respectively. This study contributes data towards the development of site specific water quality

  15. Growth and Low Temperature Transport Measurements of Pure and Doped Bismuth Selenide

    DEFF Research Database (Denmark)

    Mlack, Jerome Thomas

    Se3, which is a strong spin orbit material and a topological insulator. I describe a synthesis technique and low-temperature transport measurements of nanostructures of Bi2Se3, that when annealed with palladium show evidence of superconductivity. The growth method is a catalyst-free atmospheric...... with palladium via annealing, the transport properties of the samples can be altered to exhibit superconductivity. Thin films of palladium are deposited on prefabricated Bi2Se3 nanodevices and annealed at temperatures in excess of 100 Celsius. We find that Bi2Se3 absorbs Pd under these conditions...... pressure vapor-solid growth. The growth method yields a variety of nanostructures, and materials analysis shows ordered structures of bismuth selenide in all cases. Low-temperature measurements of as-grown nanostructures indicate tunable carrier density in all samples. By doping the nanostructures...

  16. Electron exchange between neutral and ionized impurity iron centers in vitreous arsenic selenide

    Energy Technology Data Exchange (ETDEWEB)

    Marchenko, A. V. [Herzen State Pedagogical University of Russia (Russian Federation); Terukov, E. I. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation); Egorova, A. Yu. [St.-Petersburg Mining University (Russian Federation); Kiselev, V. S.; Seregin, P. P., E-mail: ppseregin@mail.ru [Herzen State Pedagogical University of Russia (Russian Federation)

    2017-04-15

    Impurity iron atoms in vitreous arsenic-selenide As{sub 2}Se{sub 3} films modified by iron form one-electron donor centers with an ionization energy of 0.24 (3) eV (the energy is counted from the conduction-band bottom). The Fermi level is shifted with an increase in the iron concentration from the mid-gap to the donorlevel position of iron due to the filling of one-electron states of the acceptor type lying below the Fermi level. At an iron concentration of ≥3 at %, the electron-exchange process is observed between neutral and ionized iron centers resulting in a change both in the electron density and in the tensor of the electric-field gradient at iron-atom nuclei with increasing temperature above 350 K.

  17. Optoelectronic and low temperature thermoelectric studies on nanostructured thin films of silver gallium selenide

    International Nuclear Information System (INIS)

    Jacob, Rajani; Philip, Rachel Reena; Nazer, Sheeba; Abraham, Anitha; Nair, Sinitha B.; Pradeep, B.; Urmila, K. S.; Okram, G. S.

    2014-01-01

    Polycrystalline thin films of silver gallium selenide were deposited on ultrasonically cleaned soda lime glass substrates by multi-source vacuum co-evaporation technique. The structural analysis done by X-ray diffraction ascertained the formation of nano structured tetragonal chalcopyrite thin films. The compound formation was confirmed by X-ray photo-electron spectroscopy. Atomic force microscopic technique has been used for surface morphological analysis. Direct allowed band gap ∼1.78eV with high absorption coefficient ∼10 6 /m was estimated from absorbance spectra. Low temperature thermoelectric effects has been investigated in the temperature range 80–330K which manifested an unusual increase in Seebeck coefficient with negligible phonon drag toward the very low and room temperature regime. The electrical resistivity of these n-type films was assessed to be ∼2.6Ωm and the films showed good photo response

  18. Optoelectronic and low temperature thermoelectric studies on nanostructured thin films of silver gallium selenide

    Science.gov (United States)

    Jacob, Rajani; Philip, Rachel Reena; Nazer, Sheeba; Abraham, Anitha; Nair, Sinitha B.; Pradeep, B.; Urmila, K. S.; Okram, G. S.

    2014-01-01

    Polycrystalline thin films of silver gallium selenide were deposited on ultrasonically cleaned soda lime glass substrates by multi-source vacuum co-evaporation technique. The structural analysis done by X-ray diffraction ascertained the formation of nano structured tetragonal chalcopyrite thin films. The compound formation was confirmed by X-ray photo-electron spectroscopy. Atomic force microscopic technique has been used for surface morphological analysis. Direct allowed band gap ˜1.78eV with high absorption coefficient ˜106/m was estimated from absorbance spectra. Low temperature thermoelectric effects has been investigated in the temperature range 80-330K which manifested an unusual increase in Seebeck coefficient with negligible phonon drag toward the very low and room temperature regime. The electrical resistivity of these n-type films was assessed to be ˜2.6Ωm and the films showed good photo response.

  19. Photo-induced cooperative covalent-bond switching in amorphous arsenic selenide

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, O [Lviv Scientific Research Institute of Materials of SRC ' Carat' , 202, Stryjska str., Lviv, UA-290031 (Ukraine); Balitska, V [Lviv Scientific Research Institute of Materials of SRC ' Carat' , 202, Stryjska str., Lviv, UA-290031 (Ukraine); Filipecki, J [Institute of Physics of Jan Dlugosz University, 13/15, Al. Armii Krajowej, Czestochowa, PL-42201 (Poland)

    2005-01-01

    A microstructural mechanism of photoinduced transformations in amorphous arsenic selenide films was studied with IR Fourier-spectroscopy technique in 300-100 cm{sup -1} region. It was shown that stage of irreversible photostructural changes was connected with cooperative process of coordination defect formation accompanied by homopolar chemical bonds switching in heteropolar ones. On the contrary, reversible photoinduced effects were caused by heteropolar chemical bonds switching in homopolar ones, as well as additional channel of bridge heteropolar bonds switching in short-layer ones. The both processes were associated with formation of anomalously coordinated defect pairs and accompanying atomic displacements at the level of medium-range ordering. The developed mathematical simulation procedure testified in a favour of defect-related origin of the reversible photo-thermallyinduced transformations, since their kinetics corresponded to known stretched-exponential dependence, tending to bimolecular behaviour rather then to single-exponential one.

  20. Radiation-induced physical ageing in network arsenic-sulfide/selenide glasses

    International Nuclear Information System (INIS)

    Shpotyuk, M; Golovchak, R; Kozdras, A; Shpotyuk, O

    2010-01-01

    Effect of radiation-induced physical ageing is investigated by differential scanning calorimetry method in As x Se 100-x (10 ≤ x ≤ 42) and As x S 100-x (30 ≤ x ≤ 42) glasses. Obtained results are compared with conventional physical ageing at normal conditions. Significant radiation-induced physical ageing is recorded for glassy As x S 100-x within 30 ≤ x x Se 100-x glasses from the same compositional interval do not show any measurable changes in DSC curves after γ-irradiation. Observed difference in radiation-induced physical ageing in arsenic-sulfide/selenide glasses is explained by a greater lifetime of γ-induced excitations within sulfur-based network in comparison with selenium-based one.

  1. Radiation-induced physical ageing in network arsenic-sulfide/selenide glasses

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, M; Golovchak, R; Kozdras, A; Shpotyuk, O, E-mail: shpotyuk@novas.lviv.ua

    2010-11-15

    Effect of radiation-induced physical ageing is investigated by differential scanning calorimetry method in As{sub x}Se{sub 100-x} (10 {<=} x {<=} 42) and As{sub x}S{sub 100-x} (30 {<=} x {<=} 42) glasses. Obtained results are compared with conventional physical ageing at normal conditions. Significant radiation-induced physical ageing is recorded for glassy As{sub x}S{sub 100-x} within 30 {<=} x < 40 range, while As{sub x}Se{sub 100-x} glasses from the same compositional interval do not show any measurable changes in DSC curves after {gamma}-irradiation. Observed difference in radiation-induced physical ageing in arsenic-sulfide/selenide glasses is explained by a greater lifetime of {gamma}-induced excitations within sulfur-based network in comparison with selenium-based one.

  2. Organic molecules passivated Mn doped Zinc Selenide quantum dots and its properties

    International Nuclear Information System (INIS)

    Archana, J.; Navaneethan, M.; Ponnusamy, S.; Hayakawa, Y.; Muthamizhchelvan, C.

    2011-01-01

    Quantum dots of Mn doped Zinc Selenide with N-Methylaniline as the capping agent was prepared by simple and inexpensive wet chemical method. Size of the particles observed by TEM was of the order of 2-4 nm which was well consistent with the size measured by UV analysis. The presence of paramagnetic substance Mn 2+ in the ZnSe quantum dots was confirmed by EPR measurement. Mn doped ZnSe nanoparticles exhibited a strong blue emission that was strongly dependent upon the Mn dopant level and the surface passivation produced by N-Methylaniline. The stability of the product was studied by thermal analysis which shows that this product is highly suitable for opto-electronic applications.

  3. Solar Light Responsive Photocatalytic Activity of Reduced Graphene Oxide-Zinc Selenide Nanocomposite

    Science.gov (United States)

    Chakraborty, Koushik; Ibrahim, Sk; Das, Poulomi; Ghosh, Surajit; Pal, Tanusri

    2017-10-01

    Solution processable reduced graphene oxide-zinc selenide (RGO-ZnSe) nanocomposite has been successfully synthesized by an easy one-pot single-step solvothermal reaction. The RGO-ZnSe composite was characterized structurally and morphologically by the study of XRD analysis, SEM and TEM imaging. Reduction in graphene oxide was confirmed by FTIR spectroscopy analysis. Photocatalytic efficiency of RGO-ZnSe composite was investigated toward the degradation of Rhodamine B under solar light irradiation. Our study indicates that the RGO-ZnSe composite is catalytically more active compared to the controlled-ZnSe under the solar light illumination. Here, RGO plays an important role for photoinduced charge separation and subsequently hinders the electron-hole recombination probability that consequently enhances photocatalytic degradation efficiency. We expect that this type of RGO-based optoelectronics materials opens up a new avenue in the field of photocatalytic degradation of different organic water pollutants.

  4. Control of accidental releases of hydrogen selenide in vented storage cabinets

    Science.gov (United States)

    Fthenakis, V. M.; Moskowitz, P. D.; Sproull, R. D.

    1988-07-01

    Highly toxic hydrogen selenide and hydrogen sulfide gases are used in the production of copper-indium-diselenide photovoltaic cells by reactive sputtering. In the event of an accident, these gases may be released to the atmosphere and pose hazards to public and occupational safety and health. This paper outlines an approach for designing systems for the control of these releases given the uncertainty in release conditions and lack of data on the chemical systems involved. Accidental releases of these gases in storage cabinets can be controlled by either a venturi and packed-bed scrubber and carbon adsorption bed, or containment scrubbing equipment followed by carbon adsorption. These systems can effectively reduce toxic gas emissions to levels needed to protect public health. The costs of these controls (˜0.012/Wp) are samll in comparison with current (˜6/Wp) and projected (˜I/Wp) production costs.

  5. The role of isomorphous substitutions in natural selenides belonging to the pyrite group

    International Nuclear Information System (INIS)

    Bindi, Luca; Cipriani, Curzio; Pratesi, Giovanni; Trosti-Ferroni, Renza

    2008-01-01

    The present paper reports chemical and structural data of selenide minerals belonging to the pyrite group. Eighteen samples of minerals in this group with variable chemical composition (7 samples of penroseite, NiSe 2 ; 10 samples of krutaite, CuSe 2 ; 1 sample of trogtalite, CoSe 2 ) were studied by means of X-ray single-crystal diffraction and electron microprobe. On the basis of information gained from the chemical characterization, we can conclude that a complete solid solution between NiSe 2 and CuSe 2 exists in nature with the absence of pure end-members. Although verified only for the Ni-rich members, we also infer a solid solution between NiSe 2 and CoSe 2 . The unit-cell parameters were modeled using a multiple regression method as a function of the Co, Ni, and Cu contents

  6. The role of isomorphous substitutions in natural selenides belonging to the pyrite group

    Energy Technology Data Exchange (ETDEWEB)

    Bindi, Luca [Museo di Storia Naturale, sez. di Mineralogia e Litologia, Universita degli Studi di Firenze, via La Pira 4, I-50121 Firenze (Italy)], E-mail: luca.bindi@unifi.it; Cipriani, Curzio [Museo di Storia Naturale, sez. di Mineralogia e Litologia, Universita degli Studi di Firenze, via La Pira 4, I-50121 Firenze (Italy); Pratesi, Giovanni [Museo di Storia Naturale, sez. di Mineralogia e Litologia, Universita degli Studi di Firenze, via La Pira 4, I-50121 Firenze (Italy); Dipartimento di Scienze della Terra, Universita degli Studi di Firenze, via La Pira 4, I-50121 Firenze (Italy); Trosti-Ferroni, Renza [Dipartimento di Scienze della Terra, Universita degli Studi di Firenze, via La Pira 4, I-50121 Firenze (Italy)

    2008-07-14

    The present paper reports chemical and structural data of selenide minerals belonging to the pyrite group. Eighteen samples of minerals in this group with variable chemical composition (7 samples of penroseite, NiSe{sub 2}; 10 samples of krutaite, CuSe{sub 2}; 1 sample of trogtalite, CoSe{sub 2}) were studied by means of X-ray single-crystal diffraction and electron microprobe. On the basis of information gained from the chemical characterization, we can conclude that a complete solid solution between NiSe{sub 2} and CuSe{sub 2} exists in nature with the absence of pure end-members. Although verified only for the Ni-rich members, we also infer a solid solution between NiSe{sub 2} and CoSe{sub 2}. The unit-cell parameters were modeled using a multiple regression method as a function of the Co, Ni, and Cu contents.

  7. Density functional theory study of inter-layer coupling in bulk tin selenide

    Science.gov (United States)

    Song, Hong-Yue; Lü, Jing-Tao

    2018-03-01

    We study the inter-layer coupling in bulk tin selenide (SnSe) through density functional theory based calculations. Different approximations for the exchange-correlation functionals and the van der Waals interaction are employed. By performing comparison with graphite, MoS2 and black phosphorus, we analyze the inter-layer coupling from different points of view, including the binding energy, the low frequency inter-layer optical phonons, and the inter-layer charge transfer. We find that, there is a strong charge transfer between layers of SnSe, resulting in the strongest inter-layer coupling. Moreover, the charge transfer renders the inter-layer coupling in SnSe not of van der Waals type. Mechanical exfoliation has been used to fabricate mono- or few-layer graphene, MoS2 and black phosphorus. But, our results show that it may be difficult to apply similar technique to SnSe.

  8. Short-range order in amorphous thin films of indium selenides

    International Nuclear Information System (INIS)

    Zakharov, V.P.; Poltavtsev, Yu.G.; Sheremet, G.P.

    1982-01-01

    A structure of the short-range order and a character of interatomic interactions in indium selenides Insub(1-x)Sesub(x) with 0.333 <= x <= 0.75, obtained in the form of amorphous films 0.05-0.80 μm thick are studied using electron diffraction method. It is found out that mostly tetrahedrical coordination of nearest neighbours in the vicinity of indium atoms is characteristic for studied amorphous films, and coordination of selenium atoms is different. Amorphous film with x=0.75 posesses a considereably microheterogeneous structure of the short-range order, which is characterized by the presence of microunclusions of amorphous selenium and atoms of indium, octohedrically coordinated by selenium atoms

  9. Lead Selenide Nanostructures Self-Assembled across Multiple Length Scales and Dimensions

    Directory of Open Access Journals (Sweden)

    Evan K. Wujcik

    2016-01-01

    Full Text Available A self-assembly approach to lead selenide (PbSe structures that have organized across multiple length scales and multiple dimensions has been achieved. These structures consist of angstrom-scale 0D PbSe crystals, synthesized via a hot solution process, which have stacked into 1D nanorods via aligned dipoles. These 1D nanorods have arranged into nanoscale 2D sheets via directional short-ranged attraction. The nanoscale 2D sheets then further aligned into larger 2D microscale planes. In this study, the authors have characterized the PbSe structures via normal and cryo-TEM and EDX showing that this multiscale multidimensional self-assembled alignment is not due to drying effects. These PbSe structures hold promise for applications in advanced materials—particularly electronic technologies, where alignment can aid in device performance.

  10. Improved microstructure and thermoelectric properties of iodine doped indium selenide as a function of sintering temperature

    Science.gov (United States)

    Dhama, Pallavi; Kumar, Aparabal; Banerji, P.

    2018-04-01

    In this paper, we explored the effect of sintering temperature on the microstructure, thermal and electrical properties of iodine doped indium selenide in the temperature range 300 - 700 K. Samples were prepared by a collaborative process of vacuum melting, ball milling and spark plasma sintering at 570 K, 630 K and 690 K. Single phase samples were obtained at higher sintering temperature as InSe is stable only at lower temperature. With increasing sintering temperature, densities of the samples were found to improve with larger grain size formation. Negative values of Seebeck coefficient were observed which indicates n-type carrier transport. Seebeck coefficient increases with sintering temperature and found to be the highest for the sample sintered at 690 K. Thermal conductivity found to be lower in the samples sintered at lower temperatures. The maximum thermoelectric figure of merit found to be ˜ 1 at 700 K due to the enhanced power factor as a result of improved microstructure.

  11. Controllable synthesis of metal selenide heterostructures mediated by Ag2Se nanocrystals acting as catalysts

    Science.gov (United States)

    Zhou, Jiangcong; Huang, Feng; Xu, Ju; Wang, Yuansheng

    2013-09-01

    Ag2Se nanocrystals were demonstrated to be novel semiconductor mediators, or in other word catalysts, for the growth of semiconductor heterostructures in solution. This is a result of the unique feature of Ag2Se as a fast ion conductor, allowing foreign cations to dissolve and then to heterogrow the second phase. Using Ag2Se nanocrystals as catalysts, dimeric metal selenide heterostructures such as Ag2Se-CdSe and Ag2Se-ZnSe, and even multi-segment heterostructures such as Ag2Se-CdSe-ZnSe and Ag2Se-ZnSe-CdSe, were successfully synthesized. Several interesting features were found in the Ag2Se based heterogrowth. At the initial stage of heterogrowth, a layer of the second phase forms on the surface of an Ag2Se nanosphere, with a curved junction interface between the two phases. With further growth of the second phase, the Ag2Se nanosphere tends to flatten the junction surface by modifying its shape from sphere to hemisphere in order to minimize the conjunct area and thus the interfacial energy. Notably, the crystallographic relationship of the two phases in the heterostructure varies with the lattice parameters of the second phase, in order to reduce the lattice mismatch at the interface. Furthermore, a small lattice mismatch at the interface results in a straight rod-like second phase, while a large lattice mismatch would induce a tortuous product. The reported results may provide a new route for developing novel selenide semiconductor heterostructures which are potentially applicable in optoelectronic, biomedical, photovoltaic and catalytic fields.Ag2Se nanocrystals were demonstrated to be novel semiconductor mediators, or in other word catalysts, for the growth of semiconductor heterostructures in solution. This is a result of the unique feature of Ag2Se as a fast ion conductor, allowing foreign cations to dissolve and then to heterogrow the second phase. Using Ag2Se nanocrystals as catalysts, dimeric metal selenide heterostructures such as Ag2Se-CdSe and Ag2Se

  12. Dual responsive dysprosium-doped hydroxyapatite particles and toxicity reduction after functionalization with folic and glucuronic acids.

    Science.gov (United States)

    Sánchez Lafarga, Ana Karen; Pacheco Moisés, Fermín P; Gurinov, Andrey; Ortiz, Genaro Gabriel; Carbajal Arízaga, Gregorio Guadalupe

    2015-03-01

    The development of probes for biomedical applications demands materials with low toxicity levels besides fluorescence or magnetic properties to be detected by confocal microscopes or MRI resonators. Several drug delivery systems or other biomedical materials prepared with hydroxyapatite have been proposed, however, toxicity effects might arise when the size of particles is nanometric. In this study, hydroxyapatite functionalized with glucuronic or folic acids presented lower oxidative stress, measured from lipoperoxides and nitric oxide indicators in rats than pure hydroxyapatite. In separated experiments, hydroxyapatite was doped with dysprosium cations by coprecipitation producing a single crystal phase with fluorescent properties easily visualized by confocal microscopy when excited at 488nm. These particles also presented the ability to modify the proton relaxation time in T1 maps collected by magnetic resonance imaging. These modified hydroxyapatite nanoparticles could be candidates to design bimodal probes with low toxicity. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Magnetic anisotropy of dysprosium(III) in a low-symmetry environment: a theoretical and experimental investigation.

    Science.gov (United States)

    Bernot, Kevin; Luzon, Javier; Bogani, Lapo; Etienne, Mael; Sangregorio, Claudio; Shanmugam, Muralidharan; Caneschi, Andrea; Sessoli, Roberta; Gatteschi, Dante

    2009-04-22

    A mixed theoretical and experimental approach was used to determine the local magnetic anisotropy of the dysprosium(III) ion in a low-symmetry environment. The susceptibility tensor of the monomeric species having the formula [Dy(hfac)(3)(NIT-C(6)H(4)-OEt)(2)], which contains nitronyl nitroxide (NIT-R) radicals, was determined at various temperatures through angle-resolved magnetometry. These results are in agreement with ab initio calculations performed using the complete active space self-consistent field (CASSCF) method, validating the predictive power of this theoretical approach for complex systems containing rare-earth ions, even in low-symmetry environments. Susceptibility measurements performed with the applied field along the easy axis eventually permitted a detailed analysis of the temperature and field dependence of the magnetization, providing evidence that the Dy ion transmits an antiferromagnetic interaction between radicals but that the Dy-radical interaction is ferromagnetic.

  14. Watt-level dysprosium fiber laser at 3.15  μm with 73% slope efficiency.

    Science.gov (United States)

    Woodward, R I; Majewski, M R; Bharathan, G; Hudson, D D; Fuerbach, A; Jackson, S D

    2018-04-01

    Rare-earth-doped fiber lasers are emerging as promising high-power mid-infrared sources for the 2.6-3.0 μm and 3.3-3.8 μm regions based on erbium and holmium ions. The intermediate wavelength range, however, remains vastly underserved, despite prospects for important manufacturing and defense applications. Here, we demonstrate the potential of dysprosium-doped fiber to solve this problem, with a simple in-band pumped grating-stabilized linear cavity generating up to 1.06 W at 3.15 μm. A slope efficiency of 73% with respect to launched power (77% relative to absorbed power) is achieved-the highest value for any mid-infrared fiber laser to date, to the best of our knowledge. Opportunities for further power and efficiency scaling are also discussed.

  15. Investigating Phase Transform Behavior in Indium Selenide Based RAM and Its Validation as a Memory Element

    Directory of Open Access Journals (Sweden)

    Swapnil Sourav

    2016-01-01

    Full Text Available Phase transform properties of Indium Selenide (In2Se3 based Random Access Memory (RAM have been explored in this paper. Phase change random access memory (PCRAM is an attractive solid-state nonvolatile memory that possesses potential to meet various current technology demands of memory design. Already reported PCRAM models are mainly based upon Germanium-Antimony-Tellurium (Ge2Sb2Te5 or GST materials as their prime constituents. However, PCRAM using GST material lacks some important memory attributes required for memory elements such as larger resistance margin between the highly resistive amorphous and highly conductive crystalline states in phase change materials. This paper investigates various electrical and compositional properties of the Indium Selenide (In2Se3 material and also draws comparison with its counterpart mainly focusing on phase transform properties. To achieve this goal, a SPICE model of In2Se3 based PCRAM model has been reported in this work. The reported model has been also validated to act as a memory cell by associating it with a read/write circuit proposed in this work. Simulation results demonstrate impressive retentivity and low power consumption by requiring a set pulse of 208 μA for a duration of 100 μs to set the PCRAM in crystalline state. Similarly, a reset pulse of 11.7 μA for a duration of 20 ns can set the PCRAM in amorphous state. Modeling of In2Se3 based PCRAM has been done in Verilog-A and simulation results have been extensively verified using SPICE simulator.

  16. The digital structural analysis of cadmium selenide crystals by a method of ion beam thinning for high resolution electron microscopy

    International Nuclear Information System (INIS)

    Kanaya, Koichi; Baba, Norio; Naka, Michiaki; Kitagawa, Yukihisa; Suzuki, Kunio

    1986-01-01

    A digital processing method using a scanning densitometer system for structural analysis of electron micrographs was successfully applied to a study of cadmium selenide crystals, which were prepared by an argon-ion beam thinning method. Based on Fourier techniques for structural analysis from a computer-generated diffractogram, it was demonstrated that when cadmium selenide crystals were sufficiently thin to display the higher order diffraction spots at a high resolution approaching the atomic level, they constitute an alternative hexagonal lattice of imperfect wurtzite phase from a superposition of individual harmonic images by the enhanced scattering amplitude and corrected phase. From the structural analysis data, a Fourier synthetic lattice image was reconstructed, representing the precise location and three-dimensional arrangement of each of the atoms in the unit cell. Extensively enhanced lattice defect images of dislocations and stacking faults were also derived and shown graphically. (author)

  17. Fluorescence imaging technology (FI) for high-throughput screening of selenide-modified nano-TiO2 catalysts.

    Science.gov (United States)

    Wang, Liping; Lee, Jianchao; Zhang, Meijuan; Duan, Qiannan; Zhang, Jiarui; Qi, Hailang

    2016-02-18

    A high-throughput screening (HTS) method based on fluorescence imaging (FI) was implemented to evaluate the catalytic performance of selenide-modified nano-TiO2. Chemical ink-jet printing (IJP) technology was reformed to fabricate a catalyst library comprising 1405 (Ni(a)Cu(b)Cd(c)Ce(d)In(e)Y(f))Se(x)/TiO2 (M6Se/Ti) composite photocatalysts. Nineteen M6Se/Tis were screened out from the 1405 candidates efficiently.

  18. Synthesis, structure, and thermal properties of soluble hydrazinium germanium(IV) and tin(IV) selenide salts.

    Science.gov (United States)

    Mitzi, David B

    2005-05-16

    The crystal structures of two hydrazinium-based germanium(IV) and tin(IV) selenide salts are determined. (N(2)H(5))(4)Ge(2)Se(6) (1) [I4(1)cd, a = 12.708(1) Angstroms, c = 21.955(2) Angstroms, Z = 8] and (N(2)H(4))(3)(N(2)H(5))(4)Sn(2)Se(6) (2) [P, a = 6.6475(6) Angstroms, b = 9.5474(9) Angstroms, c = 9.8830(10) Angstroms, alpha = 94.110(2) degrees, beta = 99.429(2) degrees, gamma = 104.141(2) degrees, Z = 1] each consist of anionic dimers of edge-sharing metal selenide tetrahedra, M(2)Se(6)(4-) (M = Ge or Sn), separated by hydrazinium cations and, for 2, additional neutral hydrazine molecules. Substantial hydrogen bonding exists among the hydrazine/hydrazinium molecules as well as between the hydrazinium cations and the selenide anions. Whereas the previously reported tin(IV) sulfide system, (N(2)H(5))(4)Sn(2)S(6), decomposes cleanly to microcrystalline SnS(2) when heated to 200 degrees C in an inert atmosphere, higher temperatures (>300 degrees C) are required to dissociate selenium from 1 and 2 for the analogous preparations of single-phase metal selenides. The metal chalcogenide salts are highly soluble in hydrazine, as well as in a variety of amines and DMSO, highlighting the potential usefulness of these compounds as precursors for the solution deposition of the corresponding metal chalcogenide films.

  19. Study by vibration spectrometry of addition compounds of boron fluoride with some alkyl oxides, sulphides and selenides

    International Nuclear Information System (INIS)

    Le Calve, Jacques

    1966-01-01

    This research thesis reports the study of the vibration spectrum of some addition compounds of boron fluoride with alkyl oxides, sulphides and selenides. The objective was first the assignment of spectra, and then the study of the influence of the formation of a coordination bound on boron fluoride vibrations and on that of its donor. The author also tried to define correlations between spectrum and structures, and studied the effects of physical status and solvents [fr

  20. On-line complexation/cloud point preconcentration for the sensitive determination of dysprosium in urine by flow injection inductively coupled plasma-optical emission spectrometry

    International Nuclear Information System (INIS)

    Ortega, Claudia; Cerutti, Soledad; Silva, Maria F.; Olsina, Roberto A.; Martinez, Luis D.

    2003-01-01

    An on-line dysprosium preconcentration and determination system based on the hyphenation of cloud point extraction (CPE) to flow injection analysis (FIA) associated with ICP-OES was studied. For the preconcentration of dysprosium, a Dy(III)-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol complex was formed on-line at pH 9.22 in the presence of nonionic micelles of PONPE-7.5. The micellar system containing the complex was thermostated at 30 C in order to promote phase separation, and the surfactant-rich phase was retained in a microcolumn packed with cotton at pH 9.2. The surfactant-rich phase was eluted with 4 mol L -1 nitric acid at a flow rate of 1.5 mL min -1 , directly in the nebulizer of the plasma. An enhancement factor of 50 was obtained for the preconcentration of 50 mL of sample solution. The detection limit value for the preconcentration of 50 mL of aqueous solution of Dy was 0.03 μg L -1 . The precision for 10 replicate determinations at the 2.0 μg L -1 Dy level was 2.2% relative standard deviation (RSD), calculated from the peak heights obtained. The calibration graph using the preconcentration system for dysprosium was linear with a correlation coefficient of 0.9994 at levels near the detection limits up to at least 100 μg L -1 . The method was successfully applied to the determination of dysprosium in urine. (orig.)

  1. Graphite furnace atomic absorption spectrometry with a tantalum boat for the determination of yttrium, samarium, and dysprosium in a mish metal

    International Nuclear Information System (INIS)

    Daidoji, Hidehiro; Tamura, Shohei

    1982-01-01

    The determination of yttrium, samarium, and dysprodium by means of graphite-furnace atomic absorption spectrometry (AAS) was studied by a tantalum boat inserted into a graphite tube atomizer. These elements could not be determined by the use of a commercial graphite tube, In the atomization from a tantalum boat, better analytical sensitivities and negligible memory effects for these rare earths are obtained. The analytical sensitivities of yttrium, samarium, and dysprodium with the tantalum boat were 0.60 ng, 0.86 ng, and 0.17 ng respectively. This method was applied for the determination of yttrium, samarium, and dysprosium in a mish metal. The measurements were performed with slightly acidified solutions (0.01 mol dm 3 HCI or HNO 3 ). The sensitivities and the precisions for these elements decreased with increasing acid concentration. An enhancement in the sensitivities of yttrium and dysprosium upon the addition of a large excess of lanthanum, neodymium, and praseodymium salts were observed. The yttrium, samarium, and dysprosium in a mish metal were determined with both analytical curves of standard solutions containing an excess of lanthanum, cerium, and neodymium ions and of the standard addition. The precisions for this work were in the 3 - 9.3% range. (author)

  2. Phase-Engineered Type-II Multimetal-Selenide Heterostructures toward Low-Power Consumption, Flexible, Transparent, and Wide-Spectrum Photoresponse Photodetectors.

    Science.gov (United States)

    Chen, Yu-Ze; Wang, Sheng-Wen; Su, Teng-Yu; Lee, Shao-Hsin; Chen, Chia-Wei; Yang, Chen-Hua; Wang, Kuangye; Kuo, Hao-Chung; Chueh, Yu-Lun

    2018-05-01

    Phase-engineered type-II metal-selenide heterostructures are demonstrated by directly selenizing indium-tin oxide to form multimetal selenides in a single step. The utilization of a plasma system to assist the selenization facilitates a low-temperature process, which results in large-area films with high uniformity. Compared to single-metal-selenide-based photodetectors, the multimetal-selenide photodetectors exhibit obviously improved performance, which can be attributed to the Schottky contact at the interface for tuning the carrier transport, as well as the type-II heterostructure that is beneficial for the separation of the electron-hole pairs. The multimetal-selenide photodetectors exhibit a response to light over a broad spectrum from UV to visible light with a high responsivity of 0.8 A W -1 and an on/off current ratio of up to 10 2 . Interestingly, all-transparent photodetectors are successfully produced in this work. Moreover, the possibility of fabricating devices on flexible substrates is also demonstrated with sustainable performance, high strain tolerance, and high durability during bending tests. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Field Effect Transistors Using Atomically Thin Layers of Copper Indium Selenide (CuInSe)

    Science.gov (United States)

    Patil, Prasanna; Ghosh, Sujoy; Wasala, Milinda; Lei, Sidong; Vajtai, Robert; Ajayan, Pulickel; Talapatra, Saikat

    We will report fabrication of field-effect transistors (FETs) using few-layers of Copper Indium Selenide (CuInSe) flakes exfoliated from crystals grown using chemical vapor transport technique. Our transport measurements indicate n-type FET with electron mobility µ ~ 3 cm2 V-1 s-1 at room temperature when Silicon dioxide (SiO2) is used as a back gate. Mobility can be further increased significantly when ionic liquid 1-Butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6) is used as top gate. Similarly subthreshold swing can be further improved from 103 V/dec to 0.55 V/dec by using ionic liquid as a top gate. We also found ON/OFF ratio of ~ 102 for both top and back gate. Comparison between ionic liquid top gate and SiO2 back gate will be presented and discussed. This work is supported by the U.S. Army Research Office through a MURI Grant # W911NF-11-1-0362.

  4. Synthesis and Characterization of Aqueous Lead Selenide Quantum Dots for Solar Cell Application

    Science.gov (United States)

    Albert, Ancy; Sreekala, C. O.; Prabhakaran, Malini

    2018-02-01

    High quality, colloidal lead selenide (PbSe) nanoparticles possessing cube shaped morphology have been successfully synthesized by organometallic synthesis method, using oleic acid (OA) as capping agent. The use of non-coordinating solvent, 1-Octadecene (ODE), during the synthesis results in good quality nanocrystals. Morphology analysis by transmission electron microscopy reveals that cube-shaped nanocrystals with a size range of 10 nm have been produced during the synthesis. The absorption and PL spectra analysis showed an emission peak at 675 nm when excited to a wavelength of 610 nm, further confirmed the formation of PbSe nanocrystals. The surface modification of this colloidal quantum dots was then carried out using L- cysteine ligand, to make them water soluble, for solar cell application. The J-V characteristics study of this PbSe quantum dots solar cell (PbSe QDSC) showed a little power conversion efficiency which intern it shows significant advance toward effective utilization of PbSe nanocrystals sensitized in solar cells.

  5. Efficient solution-processed small molecule: Cadmium selenide quantum dot bulk heterojunction solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Vinay, E-mail: drvinaygupta@netscape.net [Physics of Energy Harvesting Division, Organic and Hybrid Solar Cell Group, CSIR-National Physical Laboratory, New Delhi-110012 (India); Department of Physics, University of California, Santa Barbara, California 93106 (United States); Upreti, Tanvi; Chand, Suresh [Physics of Energy Harvesting Division, Organic and Hybrid Solar Cell Group, CSIR-National Physical Laboratory, New Delhi-110012 (India)

    2013-12-16

    We report bulk heterojunction solar cells based on blends of solution-processed small molecule [7,7′-(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b′]dithiophene-2,6-diyl) bis(6-fluoro-4-(5′-hexyl-[2,2′-bithiophen]-5yl)benzo[c] [1,2,5] thiadiazole)] p-DTS(FBTTh{sub 2}){sub 2}: Cadmium Selenide (CdSe) (70:30, 60:40, 50:50, and 40:60) in the device configuration: Indium Tin Oxide /poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/p-DTS(FBTTh{sub 2}){sub 2}: CdSe/Ca/Al. The optimized ratio of p-DTS(FBTTh{sub 2}){sub 2}:CdSe::60:40 leads to a short circuit current density (J{sub sc}) = 5.45 mA/cm{sup 2}, open circuit voltage (V{sub oc}) = 0.727 V, and fill factor (FF) = 51%, and a power conversion efficiency = 2.02% at 100 mW/cm{sup 2} under AM1.5G illumination. The J{sub sc} and FF are sensitive to the ratio of p-DTS(FBTTh{sub 2}){sub 2}:CdSe, which is a crucial factor for the device performance.

  6. Efficient solution-processed small molecule: Cadmium selenide quantum dot bulk heterojunction solar cells

    International Nuclear Information System (INIS)

    Gupta, Vinay; Upreti, Tanvi; Chand, Suresh

    2013-01-01

    We report bulk heterojunction solar cells based on blends of solution-processed small molecule [7,7′-(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b′]dithiophene-2,6-diyl) bis(6-fluoro-4-(5′-hexyl-[2,2′-bithiophen]-5yl)benzo[c] [1,2,5] thiadiazole)] p-DTS(FBTTh 2 ) 2 : Cadmium Selenide (CdSe) (70:30, 60:40, 50:50, and 40:60) in the device configuration: Indium Tin Oxide /poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/p-DTS(FBTTh 2 ) 2 : CdSe/Ca/Al. The optimized ratio of p-DTS(FBTTh 2 ) 2 :CdSe::60:40 leads to a short circuit current density (J sc ) = 5.45 mA/cm 2 , open circuit voltage (V oc ) = 0.727 V, and fill factor (FF) = 51%, and a power conversion efficiency = 2.02% at 100 mW/cm 2 under AM1.5G illumination. The J sc and FF are sensitive to the ratio of p-DTS(FBTTh 2 ) 2 :CdSe, which is a crucial factor for the device performance

  7. Synthesis of Co-Electrospun Lead Selenide Nanostructures within Anatase Titania Nanotubes for Advanced Photovoltaics

    Directory of Open Access Journals (Sweden)

    Evan K. Wujcik

    2015-06-01

    Full Text Available Inorganic nano-scale heterostructures have many advantages over hybrid organic-inorganic dye-sensitized solar cells (DSSC or Grätzel cells, including their resistance to photo-bleaching, thermal stability, large specific surface areas, and general robustness. This study presents a first-of-its-kind low-cost all-inorganic lead selenide-anatase titania (PbSe/TiO2 nanotube heterostructure material for photovoltaic applications. Herein, PbSe nanostructures have been co-electrospun within a hollow TiO2 nanotube with high connectivity for highly efficient charge carrier flow and electron-hole pair separation. This material has been characterized by transmission electron microscopy (TEM, electron diffraction, energy dispersive X-ray spectroscopy (EDX to show the morphology and material composition of the synthesized nanocomposite. Photovoltaic characterization has shown this newly synthesized proof-of-concept material can easily produce a photocurrent under solar illumination, and, with further refinement, could reveal a new direction in photovoltaic materials.

  8. Point contacts at the copper-indium-gallium-selenide interface—A theoretical outlook

    Energy Technology Data Exchange (ETDEWEB)

    Bercegol, Adrien, E-mail: adrien.bercegol@polytechnique.edu; Chacko, Binoy; Klenk, Reiner; Lauermann, Iver; Lux-Steiner, Martha Ch. [Helmholtz-Zentrum Berlin für Materialien und Energie, Albert Einstein Straße 15, 12489 Berlin (Germany); Liero, Matthias [Weierstraß-Institut für Angewandte Analysis und Stochastik, 10117 Berlin (Germany)

    2016-04-21

    For a long time, it has been assumed that recombination in the space-charge region of copper-indium-gallium-selenide (CIGS) is dominant, at least in high efficiency solar cells with low band gap. The recent developments like potassium fluoride post deposition treatment and point-contact junction may call this into question. In this work, a theoretical outlook is made using three-dimensional simulations to investigate the effect of point-contact openings through a passivation layer on CIGS solar cell performance. A large set of solar cells is modeled under different scenarios for the charged defect levels and density, radius of the openings, interface quality, and conduction band offset. The positive surface charge created by the passivation layer induces band bending and this influences the contact (CdS) properties, making it beneficial for the open circuit voltage and efficiency, and the effect is even more pronounced when coverage area is more than 95%, and also makes a positive impact on the device performance, even in the presence of a spike at CIGS/CdS heterojunction.

  9. Swift heavy ion induced modifications in optical and electrical properties of cadmium selenide thin films

    Science.gov (United States)

    Choudhary, Ritika; Chauhan, Rishi Pal

    2017-07-01

    The modification in various properties of thin films using high energetic ion beam is an exciting area of basic and applied research in semiconductors. In the present investigations, cadmium selenide (CdSe) thin films were deposited on ITO substrate using electrodeposition technique. To study the swift heavy ion (SHI) induced effects, the deposited thin films were irradiated with 120 MeV heavy Ag9+ ions using pelletron accelerator facility at IUAC, New Delhi, India. Structural phase transformation in CdSe thin film from metastable cubic phase to stable hexagonal phase was observed after irradiation leading to decrease in the band gap from 2.47 eV to 2.12 eV. The phase transformation was analyzed through X-ray diffraction patterns. During SHI irradiation, Generation of high temperature and pressure by thermal spike along the trajectory of incident ions in the thin films might be responsible for modification in the properties of thin films.[Figure not available: see fulltext.

  10. The effect of annealing on structural, optical and photosensitive properties of electrodeposited cadmium selenide thin films

    Directory of Open Access Journals (Sweden)

    Somnath Mahato

    2017-06-01

    Full Text Available Cadmium selenide (CdSe thin films have been deposited on indium tin oxide coated glass substrate by simple electrodeposition method. X-ray Diffraction (XRD studies identify that the as-deposited CdSe films are highly oriented to [002] direction and they belong to nanocrystalline hexagonal phase. The films are changed to polycrystalline structure after annealing in air for temperatures up to 450 °C and begin to degrade afterwards with the occurrence of oxidation and porosity. CdSe completely ceases to exist at higher annealing temperatures. CdSe films exhibit a maximum absorbance in the violet to blue-green region of an optical spectrum. The absorbance increases while the band gap decreases with increasing annealing temperature. Surface morphology also shows that the increase of the annealing temperature caused the grain growth. In addition, a number of distinct crystals is formed on top of the film surface. Electrical characteristics show that the films are photosensitive with a maximum sensitivity at 350 °C.

  11. Layered bismuth selenide utilized as hole transporting layer for highly stable organic photovoltaics

    KAUST Repository

    Yuan, Zhongcheng

    2015-11-01

    Abstract Layered bismuth selenide (L-Bi2Se3) nanoplates were implemented as hole transporting layers (HTLs) for inverted organic solar cells. Device based on L-Bi2Se3 showed increasing power conversion efficiency (PCE) during ambient condition storage process. A PCE of 4.37% was finally obtained after 5 days storage, which outperformed the ones with evaporated-MoO3 using poly(3-hexylthiophene) (P3HT) as donor material and [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) as acceptor. The improved device efficiency can be attributed to the high conductivity and increasing work function of L-Bi2Se3. The work function of L-Bi2Se3 increased with the storage time in ambient condition due to the oxygen atom doping. Ultraviolet photoelectron spectroscopy and high resolution X-ray photoelectron spectroscopy were conducted to verify the increased work function, which originated from the p-type doping process. The device based on L-Bi2Se3 exhibited excellent stability in ambient condition up to 4 months, which was much improved compared to the device based on traditional HTLs. © 2015 Elsevier B.V.

  12. Zinc Selenide-Based Schottky Barrier Detectors for Ultraviolet-A and Ultraviolet-B Detection

    Directory of Open Access Journals (Sweden)

    V. Naval

    2010-01-01

    Full Text Available Wide-bandgap semiconductors such as zinc selenide (ZnSe have become popular for ultraviolet (UV photodetectors due to their broad UV spectral response. Schottky barrier detectors made of ZnSe in particular have been shown to have both low dark current and high responsivity. This paper presents the results of electrical and optical characterization of UV sensors based on ZnSe/Ni Schottky diodes fabricated using single-crystal ZnSe substrate with integrated UV-A (320–400 nm and UV-B (280–320 nm filters. For comparison, characteristics characterization of an unfiltered detector is also included. The measured photoresponse showed good discrimination between the two spectral bands. The measured responsivities of the UV-A and UV-B detectors were 50 mA/W and 10 mA/W, respectively. A detector without a UV filter showed a maximum responsivity of about 110 mA/W at 375 nm wavelength. The speed of the unfiltered detector was found to be about 300 kHz primarily limited by the RC time constant determined largely by the detector area.

  13. Workplace testing of the new single sphere neutron spectrometer based on Dysprosium activation foils (Dy-SSS)

    International Nuclear Information System (INIS)

    Bedogni, R.; Gómez-Ros, J.M.; Esposito, A.; Gentile, A.; Chiti, M.; Palacios-Pérez, L.; Angelone, M.; Tana, L.

    2012-01-01

    A photon insensitive passive neutron spectrometer consisting of a single moderating polyethylene sphere with Dysprosium activation foils arranged along three perpendicular axes was designed by CIEMAT and INFN. The device is called Dy-SSS (Dy foil-based Single Sphere Spectrometer). It shows nearly isotropic response in terms of neutron fluence up to 20 MeV. The first prototype, previously calibrated with 14 MeV neutrons, has been recently tested in workplaces having different energy and directional distributions. These are a 2.5 MeV nearly mono-chromatic and mono-directional beam available at the ENEA Frascati Neutron Generator (FNG) and the photo-neutron field produced in a 15 MV Varian CLINAC DHX medical accelerator, located in the Ospedale S. Chiara (Pisa). Both neutron spectra are known through measurements with a Bonner Sphere Spectrometer. In both cases the experimental response of the Dy-SSS agrees with the reference data. Moreover, it is demonstrated that the spectrometric capability of the new device are independent from the directional distribution of the neutron field. This opens the way to a new generation of moderation-based neutron instruments, presenting all advantages of the Bonner sphere spectrometer without the disadvantage of the repeated exposures. This concept is being developed within the NESCOFI@BTF project of INFN (Commissione Scientifica Nazionale 5).

  14. Workplace testing of the new single sphere neutron spectrometer based on Dysprosium activation foils (Dy-SSS)

    Science.gov (United States)

    Bedogni, R.; Gómez-Ros, J. M.; Esposito, A.; Gentile, A.; Chiti, M.; Palacios-Pérez, L.; Angelone, M.; Tana, L.

    2012-08-01

    A photon insensitive passive neutron spectrometer consisting of a single moderating polyethylene sphere with Dysprosium activation foils arranged along three perpendicular axes was designed by CIEMAT and INFN. The device is called Dy-SSS (Dy foil-based Single Sphere Spectrometer). It shows nearly isotropic response in terms of neutron fluence up to 20 MeV. The first prototype, previously calibrated with 14 MeV neutrons, has been recently tested in workplaces having different energy and directional distributions. These are a 2.5 MeV nearly mono-chromatic and mono-directional beam available at the ENEA Frascati Neutron Generator (FNG) and the photo-neutron field produced in a 15 MV Varian CLINAC DHX medical accelerator, located in the Ospedale S. Chiara (Pisa). Both neutron spectra are known through measurements with a Bonner Sphere Spectrometer. In both cases the experimental response of the Dy-SSS agrees with the reference data. Moreover, it is demonstrated that the spectrometric capability of the new device are independent from the directional distribution of the neutron field. This opens the way to a new generation of moderation-based neutron instruments, presenting all advantages of the Bonner sphere spectrometer without the disadvantage of the repeated exposures. This concept is being developed within the NESCOFI@BTF project of INFN (Commissione Scientifica Nazionale 5).

  15. Workplace testing of the new single sphere neutron spectrometer based on Dysprosium activation foils (Dy-SSS)

    Energy Technology Data Exchange (ETDEWEB)

    Bedogni, R., E-mail: roberto.bedogni@lnf.infn.it [INFN-LNF (Frascati National Laboratories), Via E. Fermi n. 40-00044 Frascati (Italy); Gomez-Ros, J.M. [INFN-LNF (Frascati National Laboratories), Via E. Fermi n. 40-00044 Frascati (Italy); CIEMAT, Av. Complutense 40, 28040 Madrid (Spain); Esposito, A.; Gentile, A.; Chiti, M.; Palacios-Perez, L. [INFN-LNF (Frascati National Laboratories), Via E. Fermi n. 40-00044 Frascati (Italy); Angelone, M. [ENEA C.R. Frascati, C.P. 65, 00044 Frascati (Italy); Tana, L. [A.O. Universitaria Pisana-Ospedale S. Chiara, Via Bonanno Pisano, Pisa (Italy)

    2012-08-21

    A photon insensitive passive neutron spectrometer consisting of a single moderating polyethylene sphere with Dysprosium activation foils arranged along three perpendicular axes was designed by CIEMAT and INFN. The device is called Dy-SSS (Dy foil-based Single Sphere Spectrometer). It shows nearly isotropic response in terms of neutron fluence up to 20 MeV. The first prototype, previously calibrated with 14 MeV neutrons, has been recently tested in workplaces having different energy and directional distributions. These are a 2.5 MeV nearly mono-chromatic and mono-directional beam available at the ENEA Frascati Neutron Generator (FNG) and the photo-neutron field produced in a 15 MV Varian CLINAC DHX medical accelerator, located in the Ospedale S. Chiara (Pisa). Both neutron spectra are known through measurements with a Bonner Sphere Spectrometer. In both cases the experimental response of the Dy-SSS agrees with the reference data. Moreover, it is demonstrated that the spectrometric capability of the new device are independent from the directional distribution of the neutron field. This opens the way to a new generation of moderation-based neutron instruments, presenting all advantages of the Bonner sphere spectrometer without the disadvantage of the repeated exposures. This concept is being developed within the NESCOFI@BTF project of INFN (Commissione Scientifica Nazionale 5).

  16. Self-standing nanoribbons of antimony selenide and antimony sulfide with well-defined size and band gap

    International Nuclear Information System (INIS)

    Vadapoo, Rajasekarakumar; Krishnan, Sridevi; Yilmaz, Hulusi; Marin, Carlos

    2011-01-01

    Sub-10 nm semiconducting nanostructures are crucial for the realization of nanoscale devices. Fabrication of nanostructures at this scale with homogeneous properties is challenging. Using ab initio calculations, we show that self-standing ribbons of antimony selenide and antimony sulfide of width 1.1 nm exhibit well-defined bandgaps of 1.66 and 2.16 eV, respectively. Molecular dynamics studies show that these ribbons are stable at 500 K. The one-dimensional (1D) heterostructure of these nanoribbons (Sb 2 Se 3 /Sb 2 S 3 ) along the [001] direction shows a straddling type behavior.

  17. Laser Photolysis and Thermolysis of Organic Selenides and Tellurides for Chemical Gas-phase Deposition of Nanostructured Materials

    Directory of Open Access Journals (Sweden)

    Josef Pola

    2009-03-01

    Full Text Available Laser radiation-induced decomposition of gaseous organic selenides and tellurides resulting in chemical deposition of nanostructured materials on cold surfaces is reviewed with regard to the mechanism of the gas-phase decomposition and properties of the deposited materials. The laser photolysis and laser thermolysis of the Se and Te precursors leading to chalcogen deposition can also serve as a useful approach to nanostructured chalcogen composites and IVA group (Si, Ge, Sn element chalcogenides provided that it is carried out simultaneously with laser photolysis or thermolysis of polymer and IVA group element precursor.

  18. catena-Poly[[copper(II)-bis[μ-bis(3,5-dimethyl-1H-pyrazol-4-yl) selenide

    Science.gov (United States)

    Seredyuk, Maksym; Haukka, Matti; Pavlenko, Vadim A.; Fritsky, Igor O.

    2009-01-01

    In the title compound, {[Cu(C10H14N4Se)2](ClO4)2}n, the CuII ion is located on a twofold rotation axis and has a tetra­gonally distorted square-planar geometry constituted by four N atoms. A pair of bis(3,5-dimethyl-1H-pyrazol-4-yl) selenide (L) ligands bridges the copper centers into a polymeric chain extending along [001]. The perchlorate anions are involved in inter­molecular N—H⋯O hydrogen bonding, which links the chains into layers parallel to the bc plane. PMID:21578140

  19. catena-Poly[[copper(II-bis[μ-bis(3,5-dimethyl-1H-pyrazol-4-yl selenide

    Directory of Open Access Journals (Sweden)

    Maksym Seredyuk

    2009-11-01

    Full Text Available In the title compound, {[Cu(C10H14N4Se2](ClO42}n, the CuII ion is located on a twofold rotation axis and has a tetragonally distorted square-planar geometry constituted by four N atoms. A pair of bis(3,5-dimethyl-1H-pyrazol-4-yl selenide (L ligands bridges the copper centers into a polymeric chain extending along [001]. The perchlorate anions are involved in intermolecular N—H...O hydrogen bonding, which links the chains into layers parallel to the bc plane.

  20. Analysis on the Performance of Copper Indium Gallium Selenide (CIGS Based Photovoltaic Thermal

    Directory of Open Access Journals (Sweden)

    Zulkepli Afzam

    2016-01-01

    Full Text Available This paper deals with the efficiency improvement of Copper Indium Gallium Selenide (CIGS Photovoltaic (PV and also solar thermal collector. Photovoltaic thermal (PV/T can improve overall efficiency for PV and also solve the problem of limited roof space at urban area. Objective of this study is to clarify the effect of mass flow rate on the efficiency of the PV/T system. A CIGS solar cell is used with rated output power 65 W and 1.18 m2 of area. 4 set of experiments were carried out, which were: thermal collector with 0.12 kg/s flow rate, PV/T with 0.12 kg/s flow rate, PV/T with 0.09 kg/s flow rate and PV. It was found that PV/T with 0.12 kg/s flow rate had the highest electrical efficiency, 2.92 %. PV/T with 0.09 kg/s flow rate had the lowest electrical efficiency, 2.68 %. It also had 2 % higher overall efficiency. The efficiency gained is low due to several factors. The rated output power of the PV is low for the area of 1.18 m2. The packing factor of the PV also need to be considered as it may not be operated at the optimal packing factor. Furthermore, aluminium sheet of the PV may affect the PV temperature due to high thermal conductivity. Further study on more values of mass flow rate and also other parameters that affect the efficiency of the PV/T is necessary.

  1. Structural and electrochemical analysis of chemically synthesized microcubic architectured lead selenide thin films

    Science.gov (United States)

    Bhat, T. S.; Shinde, A. V.; Devan, R. S.; Teli, A. M.; Ma, Y. R.; Kim, J. H.; Patil, P. S.

    2018-01-01

    The present work deals with the synthesis of lead selenide (PbSe) thin films by simple and cost-effective chemical bath deposition method with variation in deposition time. The structural, morphological, and electrochemical properties of as-deposited thin films were examined using characterization techniques such as X-ray diffraction spectroscopy (XRD), field-emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy. XRD reveals formation of rock salt phase cubic structured PbSe. FE-SEM images show the formation of microcubic structured morphology. The existence of the PbSe is confirmed from the XPS analysis. On the other hand, CV curves show four reaction peaks corresponding to oxidation [PbSe and Pb(OH)2] and reduction (PbO2 and Pb(OH)2) at the surface of PbSe thin films. The PbSe:2 sample deposited for 80 min. shows maximum specific capacitance of 454 ± 5 F g- 1 obtained at 0.25 mA cm- 2 current density. The maximum energy density of 69 Wh kg- 1 was showed by PbSe:2 electrode with a power density of 1077 W kg- 1. Furthermore, electrochemical impedance studies of PbSe:2 thin film show 80 ± 3% cycling stability even after 500 CV cycles. Such results show the importance of microcubic structured PbSe thin film as an anode in supercapacitor devices.

  2. A transparent nickel selenide counter electrode for high efficient dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Jia; Wu, Jihuai, E-mail: jhwu@hqu.edu.cn; Jia, Jinbiao; Ge, Jinhua; Bao, Quanlin; Wang, Chaotao; Fan, Leqing

    2017-04-15

    Highlights: • Ni{sub 0.85}Se was obtained by hydrothermal way and the film was gained by spin-coating. • Ni{sub 0.85}Se film has good conductivity and excellent electrocatalytic activity. • DSSC based on transparent Ni{sub 0.85}Se counter electrode obtains PCE of 8.96%. • The PCE reaches 10.76% when putting a mirror under Ni{sub 0.85}Se counter electrode. - Abstract: Nickel selenide (Ni{sub 0.85}Se) was synthesized by a facile one-step hydrothermal reaction and Ni{sub 0.85}Se film was prepared by spin-coating Ni{sub 0.85}Se ink on FTO and used as counter electrode (CE) in dye-sensitized solar cells (DSSC). The Ni{sub 0.85}Se CEs not only show high transmittance in visible range, but also possess remarkable electrocatalytic activity toward I{sup −}/I{sub 3}{sup −}. The electrocatalytic ability of Ni{sub 0.85}Se films was verified by cyclic voltammetry, electrochemical impedance spectroscopy and Tafel polarization curves. The DSSC using Ni{sub 0.85}Se CE exhibits a power conversion efficiency (PCE) of 8.96%, while the DSSC consisting of sputtered Pt CE only exhibits a PCE of 8.15%. When adding a mirror under Ni{sub 0.85}Se CE, the resultant DSSC exhibits a PCE of 10.76%, which exceeds that of a DSSC based on sputtered Pt CE (8.44%) by 27.49%.

  3. Transparent nickel selenide used as counter electrode in high efficient dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Jinbiao; Wu, Jihuai, E-mail: jhwu@hqu.edu.cn; Tu, Yongguang; Huo, Jinghao; Zheng, Min; Lin, Jianming

    2015-08-15

    Highlights: • A transparent Ni{sub 0.85}Se is prepared by a facile solvothermal reaction. • Ni{sub 0.85}Se electrode has better electrocatalytic activity than Pt electrode. • DSSC with Ni{sub 0.85}Se electrode obtains efficiency of 8.88%, higher than DSSC with Pt. • DSSC with Ni{sub 0.85}Se/mirror electrode achieves an efficiency of 10.19%. - Abstract: A transparent nickel selenide (Ni{sub 0.85}Se) is prepared by a facile solvothermal reaction and used as an efficient Pt-free counter electrode (CE) for dye-sensitized solar cells (DSSCs). Field emission scanning electron microscopy observes that the as-prepared Ni{sub 0.85}Se possesses porous structure. Cyclic voltammogram measurement indicates that Ni{sub 0.85}Se electrode has larger current density than Pt electrode. Electrochemical impedance spectroscopy shows that the Ni{sub 0.85}Se electrode has lower charge-transfer resistance than Pt electrode. Under simulated solar light irradiation with intensity of 100 mW cm{sup −2} (AM 1.5), the DSSC based on the Ni{sub 0.85}Se CE achieves a power conversion efficiency (PCE) of 8.88%, which is higher than the solar cell based on Pt CE (8.13%). Based on the transparency of Ni{sub 0.85}Se, the DSSC with Ni{sub 0.85}Se/mirror achieves a PCE of 10.19%.

  4. Oxide perovskites with tetravalent dysprosium and compounds of the type Ba/sub 3/RE/sub 4/O/sub 9/ (RE = Rare Earth Element)

    Energy Technology Data Exchange (ETDEWEB)

    Brauer, G; Kristen, H [Freiburg Univ. (Germany, F.R.)

    1980-03-01

    In analogy to our investigations concerning tetravalent Nd in oxide perovskites, we also tried to stabilize dysprosium(IV) by incorporation in host-lattices with the perovskite structure. As host-lattices we used BaCeO/sub 3/, BaTbO/sub 3/, and SrTbO/sub 3/. Only in Ba(Ce, Dy)O/sub 3/ we could trace Dy(IV) with certainty. Among the prepared mixed oxides, also the phase Ba/sub 3/Dy/sub 4/O/sub 9/ occured. The lattice parameters of several phases of this latter type were redetermined.

  5. Effect of solvents on relation of intensities of bands of luminescence spectra of terbium and dysprosium ions in solutions of their complexes with acetoacetic ester

    International Nuclear Information System (INIS)

    Kononenko, L.I.; Bel'tyukova, S.V.; Meshkova, S.B.; Kravchenko, T.B.; Poluehktov, N.S.

    1978-01-01

    An investigation is made of the effect of different solvents on the ratio of the intensity of luminescence spectrum bands of terbium and dysprosium ions, corresponding and not corresponding to ''supersensitive'' transitions in complex compounds with acetoacetic ether. A dependence is established between these values and the dielectric constant of the solvent, and also parallels in their changes, which indicate the similar manifestation of the effect of solvents in both elements. A correlation is observed between ratios of the intensity of luminescence spectrum bands and values of forces of neodymium complex absorption band oscillators in different solvents

  6. Optical amplifier operating at 1.3 microns useful for telecommunications and based on dysprosium-doped metal chloride host materials

    Energy Technology Data Exchange (ETDEWEB)

    Page, R.H.; Schaffers, K.I.; Payne, S.A.; Krupke, W.F.; Beach, R.J.

    1997-12-02

    Dysprosium-doped metal chloride materials offer laser properties advantageous for use as optical amplifiers in the 1.3 {micro}m telecommunications fiber optic network. The upper laser level is characterized by a millisecond lifetime, the host material possesses a moderately low refractive index, and the gain peak occurs near 1.31 {micro}m. Related halide materials, including bromides and iodides, are also useful. The Dy{sup 3+}-doped metal chlorides can be pumped with laser diodes and yield 1.3 {micro}m signal gain levels significantly beyond those currently available. 9 figs.

  7. Optical amplifier operating at 1.3 microns useful for telecommunications and based on dysprosium-doped metal chloride host materials

    Energy Technology Data Exchange (ETDEWEB)

    Page, Ralph H. (San Ramon, CA); Schaffers, Kathleen I. (Pleasanton, CA); Payne, Stephen A. (Castro Valley, CA); Krupke, William F. (Pleasanton, CA); Beach, Raymond J. (Livermore, CA)

    1997-01-01

    Dysprosium-doped metal chloride materials offer laser properties advantageous for use as optical amplifiers in the 1.3 .mu.m telecommunications fiber optic network. The upper laser level is characterized by a millisecond lifetime, the host material possesses a moderately low refractive index, and the gain peak occurs near 1.31 .mu.m. Related halide materials, including bromides and iodides, are also useful. The Dy.sup.3+ -doped metal chlorides can be pumped with laser diodes and yield 1.3 .mu.m signal gain levels significantly beyond those currently available.

  8. Determination of Diclofenac on a Dysprosium Nanowire- Modified Carbon Paste Electrode Accomplished in a Flow Injection System by Advanced Filtering

    Directory of Open Access Journals (Sweden)

    Ali Akbar Moosavi-Movahedi

    2009-09-01

    Full Text Available A new detection technique called Fast Fourier Transform Square-Wave Voltammetry (FFT SWV is based on measurements of electrode admittance as a function of potential. The response of the detector (microelectrode, which is generated by a redox processes, is fast, which makes the method suitable for most applications involving flowing electrolytes. The carbon paste electrode was modified by nanostructures to improve sensitivity. Synthesized dysprosium nanowires provide a more effective nanotube-like surface [1-4] so they are good candidates for use as a modifier for electrochemical reactions. The redox properties of diclofenac were used for its determination in human serum and urine samples. The support electrolyte that provided a more defined and intense peak current for diclofenac determination was a 0.05 mol L−1 acetate buffer pH = 4.0. The drug presented an irreversible oxidation peak at 850 mV vs. Ag/AgCl on a modified nanowire carbon paste electrode which produced high current and reduced the oxidation potential by about 100 mV. Furthermore, the signal-to-noise ratio was significantly increased by application of a discrete Fast Fourier Transform (FFT method, background subtraction and two-dimensional integration of the electrode response over a selected potential range and time window. To obtain the much sensivity the effective parameters such as frequency, amplitude and pH was optimized. As a result, CDL of 2.0 × 10−9 M and an LOQ of 5.0 × 10−9 M were found for the determination for diclofenac. A good recovery was obtained for assay spiked urine samples and a good quantification of diclofenac was achieved in a commercial formulation.

  9. Phase diagram of (Li(1-x)Fe(x))OHFeSe: a bridge between iron selenide and arsenide superconductors.

    Science.gov (United States)

    Dong, Xiaoli; Zhou, Huaxue; Yang, Huaixin; Yuan, Jie; Jin, Kui; Zhou, Fang; Yuan, Dongna; Wei, Linlin; Li, Jianqi; Wang, Xinqiang; Zhang, Guangming; Zhao, Zhongxian

    2015-01-14

    Previous experimental results have shown important differences between iron selenide and arsenide superconductors which seem to suggest that the high-temperature superconductivity in these two subgroups of iron-based families may arise from different electronic ground states. Here we report the complete phase diagram of a newly synthesized superconducting (SC) system, (Li1-xFex)OHFeSe, with a structure similar to that of FeAs-based superconductors. In the non-SC samples, an antiferromagnetic (AFM) spin-density-wave (SDW) transition occurs at ∼127 K. This is the first example to demonstrate such an SDW phase in an FeSe-based superconductor system. Transmission electron microscopy shows that a well-known √5×√5 iron vacancy ordered state, resulting in an AFM order at ∼500 K in AyFe2-xSe2 (A = metal ions) superconductor systems, is absent in both non-SC and SC samples, but a unique superstructure with a modulation wave vector q = (1)/2(1,1,0), identical to that seen in the SC phase of KyFe2-xSe2, is dominant in the optimal SC sample (with an SC transition temperature Tc = 40 K). Hence, we conclude that the high-Tc superconductivity in (Li1-xFex)OHFeSe stems from the similarly weak AFM fluctuations as FeAs-based superconductors, suggesting a universal physical picture for both iron selenide and arsenide superconductors.

  10. Remarkable photo-catalytic degradation of malachite green by nickel doped bismuth selenide under visible light irradiation

    International Nuclear Information System (INIS)

    Kulsi, Chiranjit; Ghosh, Amrita; Mondal, Anup; Kargupta, Kajari; Ganguly, Saibal; Banerjee, Dipali

    2017-01-01

    Highlights: • Bi_2Se_3 and Ni doped Bi_2Se_3 were synthesized by solvothermal approach. • Presence of nickel was confirmed by X-ray photoelectron spectroscopy (XPS) measurement. • Complete degradation of malachite green (MG) dye was achieved by Ni doped Bi_2Se_3 with H_2O_2. • Remarkable photo-catalytic degradation by doped bismuth selenide has been explained. • Scavenger tests show degradation of MG is mainly dominated by ·OH oxidation process. - Abstract: Bismuth selenide (Bi_2Se_3) and nickel (Ni) doped Bi_2Se_3 were prepared by a solvothermal approach to explore the photo-catalytic performance of the materials in degradation of malachite green (MG). The presence of nickel was confirmed by X-ray photoelectron spectroscopy (XPS) measurement in doped Bi_2Se_3. The results showed that the nickel doping played an important role in microstructure and photo-catalytic activity of the samples. Nickel doped Bi_2Se_3 sample exhibited higher photo-catalytic activity than that of the pure Bi_2Se_3 sample under visible-light irradiation. The photo-catalytic degradation followed first-order reaction kinetics. Fast degradation kinetics and complete (100% in 5 min of visible light irradiation) removal of MG was achieved by nickel doped Bi_2Se_3 in presence of hydrogen peroxide (H_2O_2) due to modification of band gap energies leading to suppression of photo-generated electron-hole recombination.

  11. A study on the optics of copper indium gallium (di)selenide (CIGS) solar cells with ultra-thin absorber layers

    NARCIS (Netherlands)

    Xu, M.; Wachters, A.J.H.; Van Deelen, J.; Mourad, M.C.D.; Buskens, P.J.P.

    2014-01-01

    We present a systematic study of the effect of variation of the zinc oxide (ZnO) and copper indium gallium (di)selenide (CIGS) layer thickness on the absorption characteristics of CIGS solar cells using a simulation program based on finite element method (FEM). We show that the absorption in the

  12. Methods of making copper selenium precursor compositions with a targeted copper selenide content and precursor compositions and thin films resulting therefrom

    Science.gov (United States)

    Curtis, Calvin J [Lakewood, CO; Miedaner, Alexander [Boulder, CO; van Hest, Marinus Franciscus Antonius Maria; Ginley, David S [Evergreen, CO; Leisch, Jennifer [Denver, CO; Taylor, Matthew [West Simsbury, CT; Stanbery, Billy J [Austin, TX

    2011-09-20

    Precursor compositions containing copper and selenium suitable for deposition on a substrate to form thin films suitable for semi-conductor applications. Methods of forming the precursor compositions using primary amine solvents and methods of forming the thin films wherein the selection of temperature and duration of heating controls the formation of a targeted species of copper selenide.

  13. On the annealing behaviour of dysprosium ion implanted nickel: a combined study using Rutherford backscattering, transmission electron microscopy, and total current spectroscopy

    International Nuclear Information System (INIS)

    Chadderton, L.T.; Johnson, E.

    1977-01-01

    Despite continuing improvements in applications of the analytical method of Rutherford backscattering (RBS) to solid state physics it is recognized that more complete information can be obtained if other techniques - for example transmission electron microscopy (TEM) - are employed simultaneously. Experiments are described in which a combined RBS and TEM study of the annealing of nickel, rendered amorphous by implantation of 20 keV dysprosium ions is supplemented with a completely new technique - total current spectroscopy (TCS). In TCS low energy electrons (0-15 eV) are used to probe the damaged nickel. Observations have been made during annealing of both the reappearance of the bulk band structure of the metal and of a 'surface peak' which is highly sensitive to the recovery process. Changes in the height of the surface peak reveal three sharp annealing stages, the first two being preceded by reverse annealing which correlates well with RBS and TEM results. The first annealing stage - following the amorphous to crystalline transition - may be associated with electronic effects in the vicinity of the Curie point. Changes in the position of the surface peak allow one to trace the diffusion of dysprosium to the surface. Quantum mechanical resonances at the damage/crystal interface have also been followed throughout annealing. The initially amorphous layer (approximately 2.2nm) increases in thickness slightly during recovery. (Auth.)

  14. Cytocompatibility of direct water synthesized cadmium selenide quantum dots in colo-205 cells

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Torres, Marcos R. [Universidad Metropolitana, Nanomaterials Science Laboratory, School of Science and Technology (United States); Velez, Christian; Zayas, Beatriz [Universidad Metropolitana, ChemTox Laboratory, School of Environmental Affairs (United States); Rivera, Osvaldo [Universidad Metropolitana, Nanomaterials Science Laboratory, School of Science and Technology (United States); Arslan, Zikri [Jackson State University, Department of Chemistry (United States); Gonzalez-Vega, Maxine N. [Universidad Metropolitana, Nanomaterials Science Laboratory, School of Science and Technology (United States); Diaz-Diestra, Daysi; Beltran-Huarac, Juan; Morell, Gerardo [University of Puerto Rico, Molecular Science Research Center (United States); Primera-Pedrozo, Oliva M., E-mail: oprimera1@suagm.edu [Universidad Metropolitana, Nanomaterials Science Laboratory, School of Science and Technology (United States)

    2015-06-15

    Cadmium selenide quantum dots (CdSe QDs), inorganic semiconducting nanocrystals, are alluring increased attraction due to their highly refined chemistry, availability, and super tunable optical properties suitable for many applications in different research areas, such as photovoltaics, light-emitting devices, environmental sciences, and nanomedicine. Specifically, they are being widely used in bio-imaging in contrast to organic dyes due to their high brightness and improved photo-stability, and their ability to tune their absorption and emission spectra upon changing the crystal size. The production of CdSe QDs is mostly assisted by trioctylphosphine oxide compound, which acts as solvent or solubilizing agent and renders the QDs soluble in organic compounds (such as toluene, chloroform, and hexane) that are highly toxic. To circumvent the toxicity-related factor in CdSe QDs, we report the synthesis of CdSe QDs capped with thioglycolic acid (TGA) in an aqueous medium, and their biocompatibility in colo-205 cancer cells. In this study, the [Cd{sup 2+}]/[TGA] ratio was adjusted to 11:1 and the Se concentration (10 and 15 mM) was monitored in order to evaluate its influence on the optical properties and cytocompatibility. QDs resulted to be quite stable in water (after purification) and RPMI cell medium and no precipitation was observed for long contact times, making them appealing for in vitro experiments. The spectroscopy analysis, advanced electron microscopy, and X-ray diffractometry studies indicate that the final products were successfully formed exhibiting an improved optical response. Colo-205 cells being exposed to different concentrations of TGA-capped CdSe QDs for 12, 24, and 48 h with doses ranging from 0.5 to 2.0 mM show high tolerance reaching cell viabilities as high as 93 %. No evidence of cellular apoptotic pathways was observed as pointed out by our Annexin V assays at higher concentrations. Moreover, confocal microscopy analysis conducted to

  15. Depression-like behavior and mechanical allodynia are reduced by bis selenide treatment in mice with chronic constriction injury: a comparison with fluoxetine, amitriptyline, and bupropion.

    Science.gov (United States)

    Jesse, Cristiano R; Wilhelm, Ethel A; Nogueira, Cristina W

    2010-12-01

    Neuropathic pain is associated with significant co-morbidities, including depression, which impact considerably on the overall patient experience. Pain co-morbidity symptoms are rarely assessed in animal models of neuropathic pain. Neuropathic pain is characterized by hyperexcitability within nociceptive pathways and remains difficult to treat with standard analgesics. The present study determined the effect of bis selenide and conventional antidepressants (fluoxetine, amitriptyline, and bupropion) on neuropathic pain using mechanical allodynic and on depressive-like behavior. Male mice were subjected to chronic constriction injury (CCI) or sham surgery and were assessed on day 14 after operation. Mice received oral treatment with bis selenide (1-5 mg/kg), fluoxetine, amitriptyline, or bupropion (10-30 mg/kg). The response frequency to mechanical allodynia in mice was measured with von Frey hairs. Mice were evaluated in the forced swimming test (FST) test for depression-like behavior. The CCI procedure produced mechanical allodynia and increased depressive-like behavior in the FST. All of the drugs produced antiallodynic effects in CCI mice and produced antidepressant effects in control mice without altering locomotor activity. In CCI animals, however, only the amitriptyline and bis selenide treatments significantly reduced immobility in the FST. These data demonstrate an important dissociation between the antiallodynic and antidepressant effects in mice when tested in a model of neuropathic pain. Depressive behavior in CCI mice was reversed by bis selenide and amitriptyline but not by the conventional antidepressants fluoxetine and buproprion. Bis selenide was more potent than the other drugs tested for antidepressant-like and antiallodynic effects in mice.

  16. Evolution of the chemical bonding nature and electrode activity of indium selenide upon the composite formation with graphene nanosheets

    International Nuclear Information System (INIS)

    Oh, Seung Mi; Lee, Eunsil; Adpakpang, Kanyaporn; Patil, Sharad B.; Park, Mi Jin; Lim, Young Soo; Lee, Kyu Hyoung; Kim, Jong-Young; Hwang, Seong-Ju

    2015-01-01

    Graphical abstract: Display Omitted -- Highlights: • In 4 Se 2.85 @graphene nanocomposite is easily prepared by high energy mechanical milling process. • The bond covalency of In 4 Se 2.85 is notably changed upon the composite formation with graphene. • In 4 Se 2.85 @graphene nanocomposite shows promising anode performance for lithium ion battery. -- Abstract: Evolution of the chemical bonding nature and electrochemical activity of indium selenide upon the composite formation with carbon species is systematically investigated. Nanocomposites of In 4 Se 2.85 @graphene and In 4 Se 2.85 @carbon-black are synthesized via a solid state reaction between In and Se elements, and the following high energy mechanical milling of In 4 Se 2.85 with graphene and carbon-black, respectively. The high energy mechanical milling (HEMM) of In 4 Se 2.85 with carbon species gives rise to a decrease of particle size with a significant depression of the crystallinity of In 4 Se 2.85 phase. In contrast to the composite formation with carbon-black, that with graphene induces a notable decrease of (In−Se) bond covalency, underscoring significant chemical interaction between graphene and In 4 Se 2.85 . Both the nanocomposites of In 4 Se 2.85 @graphene and In 4 Se 2.85 @carbon-black show much better anode performance for lithium ion batteries with larger discharge capacity and better cyclability than does the pristine In 4 Se 2.85 material, indicating the beneficial effect of composite formation on the electrochemical activity of indium selenide. Between the present nanocomposites, the electrode performance of the In 4 Se 2.85 @graphene nanocomposite is superior to that of the In 4 Se 2.85 @carbon-black nanocomposite, which is attributable to the weakening of (In−Se) bonds upon the composite formation with graphene as well as to the better mixing between In 4 Se 2.85 and graphene. The present study clearly demonstrates that the composite formation with graphene has strong influence

  17. Four new dysprosium and neodymium octamolybdate hydrates: assembly of RE2(Mo8O27) sheets and topotactic transformations.

    Science.gov (United States)

    Kuang, Xiaojun; Evans, Ivana R

    2010-07-05

    Four new Dy and Nd hydrated octamolybdate materials have been prepared: [Dy(2)(H(2)O)(12)](Mo(8)O(27)) x 8 H(2)O, [Dy(2)(H(2)O)(6)](Mo(8)O(27)), [Nd(2)(H(2)O)(12)](Mo(8)O(27)) x 6 H(2)O, and [Nd(2)(H(2)O)(6)]Mo(8)O(27) x 3 H(2)O. They adopt one known and three new structure types, which we have determined ab initio from powder X-ray diffraction data. The four compounds contain the same basic structural building block, in the form of RE(2)Mo(8)O(27) (RE = Dy, Nd) chains, which are arranged differently for the two rare earths in the fully hydrated precursor materials. [Dy(2)(H(2)O)(12)](Mo(8)O(27)) x 8 H(2)O comprises isolated Dy(2)Mo(8)O(27) chains assembled in a zigzag manner along the a axis with interspersed crystallized water molecules, which differs from the parallel arrangements of isolated Nd(2)Mo(8)O(27) chains in [Nd(2)(H(2)O)(12)](Mo(8)O(27)) x 6 H(2)O. Partial dehydration of the two precursors leads to new phases [Dy(2)(H(2)O)(6)](Mo(8)O(27)) and [Nd(2)(H(2)O)(6)]Mo(8)O(27) x 3 H(2)O, respectively, prior to complete dehydration, which leads to initially amorphous and eventually crystalline rare-earth molybdenum mixed metal oxides. Both initial transformations occur topotactically. Partial dehydration of the Dy phase condenses the assembly of the Dy(2)Mo(8)O(27) chains principally along the a axis, leading to a 3-dimensional (3D) framework, with each Dy bridging two (Mo(8)O(27))(6-) sheets in the product. The partial dehydration of the Nd precursor condenses the assembly of Nd(2)Mo(8)O(27) chains along the [110] axis, leading to a 3D framework where each Nd bridges three (Mo(8)O(27))(6-) units. Both new dysprosium octamolybdates adopt noncentrosymmetric polar structures in space group P2(1) and are second harmonic generation (SHG) active.

  18. Microstructure and thermal properties of dysprosium and thulium co-doped barium titanate ceramics for high performance multilayer ceramic capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jinseong; Kim, Dowan; Noh, Taimin [School of Materials Science and Engineering, Pusan National University, Busan 609-735 (Korea, Republic of); Ahn, Byungmin [Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-0241 (United States); Lee, Heesoo, E-mail: heesoo@pusan.ac.kr [School of Materials Science and Engineering, Pusan National University, Busan 609-735 (Korea, Republic of)

    2011-09-15

    Highlights: > Dy/Tm co-doping method in BaTiO{sub 3} was suggested to improve electrical properties and temperature stability simultaneously. > We examined these properties in terms of microstructural analysis and substitution rate. > Increase of Dy{sub 2}O{sub 3} addition enhanced dielectric constant. > Increase of Tm{sub 2}O{sub 3} addition enhanced temperature stability. > Improved electrical properties and temperature stability through Dy/Tm co-doping were deduced from formation of electrons and core-shell structure. - Abstract: The co-doping characteristics on microstructure and thermal properties of barium titanate (BaTiO{sub 3}) were investigated to elucidate formation of core-shell structure by dysprosium (Dy) and thulium (Tm) addition in the BaTiO{sub 3}-Dy{sub 2}O{sub 3}-Tm{sub 2}O{sub 3} system. The dielectrics co-doped with 0.7 mol% Dy{sub 2}O{sub 3} and 0.3 mol% Tm{sub 2}O{sub 3} had the dielectric constant up to 2200 as a function of temperature, which was 30% higher than that of specimen containing only Tm{sub 2}O{sub 3} at the room temperature. It could be explained by the fact that the increase of Dy{sub 2}O{sub 3} addition contributed to the improvement of dielectric constant. On the other hand, the rapid diffusion rate of Dy{sup 3+} ions in BaTiO{sub 3} showed an adverse effect on temperature stability caused by destruction of core-shell. As the compensation for shell expansion in BaTiO{sub 3}, the reinforcement of the core-shell structure through the addition of Tm{sub 2}O{sub 3} was confirmed by TEM-EDS analysis and attributed the temperature coefficient of capacitance (TCC) in a reliability condition (-55 deg. C to 125 deg. C, {Delta}C = {+-}15% or less). The enhanced electrical properties and temperature stability could be deduced from the generation of electrons and the formation core-shell structure in co-doped BaTiO{sub 3} system respectively.

  19. Crystal structure of non-stoichiometric copper selenides studied by neutron scattering and X-ray diffraction

    International Nuclear Information System (INIS)

    Bikkulova, N.N.; Yagafarova, Z.A.; Asylguzhina, G.N.; Danilkin, S.A.; Fuess, H.; Skomorokhov, A.N.; Yadrovskii, E.L.; Beskrovnyi, A.I.

    2003-01-01

    Structural characteristics of non-stoichiometric copper selenides were studied by the elastic neutron and X-ray scattering techniques. Rietveld analysis was used to refine the structure of the high-temperature β-phase of the Cu 1.75 Se, Cu 1.78 Se, and Cu 1.83 Se samples. The homogeneity ranges of the cubic phase were determined. The modification of the crystal structure accompanying the β-α phase transition was studied for Cu 1.75 Se and Cu 1.98 Se compounds within the 443-10 K temperature range. It was shown that the phase transition is accompanied by distortions of the fcc lattice and the ordering of copper ions

  20. Post-test analysis of components from selenide isotope generator modules M-7, M-15, and M-18

    International Nuclear Information System (INIS)

    Wei, G.C.; Keiser, J.R.; Crouse, R.S.; Allen, M.D.; Schaffhauser, A.C.

    1979-05-01

    Several critical components removed from SIG (Selenide Isotope Generator) thermoelectric modules M-7, M-15C, M-15D, and M-18 were examined. These modules failed to show the predicted stability and conversion efficiency. Understanding the degradation and identifying means for preventing it necessitated detailed post-test examinations of key parts in the modules. Steel springs, which provided pressure for contacts at the hot and cold ends of P- or N-legs, relaxed more than expected. Beryllium oxide insulators had dark deposits that caused electrical shorts. The GdSe 1 49 N-leg exhibited cracking. The (Cu,Ag) 2 Se P-leg lost weight or sublimed excessively in module M-7 and more than expected in the other modules

  1. Synthesis and characterization of hexagonal nano-sized nickel selenide by simple hydrothermal method assisted by CTAB

    Energy Technology Data Exchange (ETDEWEB)

    Sobhani, Azam [Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P.O. Box 87317-51167 (Iran, Islamic Republic of); Davar, Fatemeh [Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P.O. Box 87317-51167 (Iran, Islamic Republic of); Salavati-Niasari, Masoud, E-mail: salavati@kashanu.ac.ir [Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P.O. Box 87317-51167 (Iran, Islamic Republic of); Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P.O. Box 87317-51167 (Iran, Islamic Republic of)

    2011-07-01

    Nano-sized nickel selenide powders have been successfully synthesized via an improved hydrothermal route based on the reaction between NiCl{sub 2}.6H{sub 2}O, SeCl{sub 4} and hydrazine (N{sub 2}H{sub 4}.H{sub 2}O) in water, in present of cetyltrimethyl ammonium bromide (CTAB) as surfactant, at various conditions. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray energy dispersive spectroscopy analysis. Effects of temperature, reaction time and reductant agent on the morphology, the particle sizes and the phase of the final products have been investigated. It was found that the phase and morphology of the products could be greatly influenced by these parameters. The synthesis procedure is simple and uses less toxic reagents than the previously reported methods. Photoluminescence (PL) was used to study the optical properties of NiSe samples.

  2. Chemical bath deposited zinc sulfide buffer layers for copper indium gallium sulfur-selenide solar cells and device analysis

    International Nuclear Information System (INIS)

    Kundu, Sambhu; Olsen, Larry C.

    2005-01-01

    Cadmium-free copper indium gallium sulfur-selenide (CIGSS) thin film solar cells have been fabricated using chemical bath deposited (CBD) zinc sulfide (ZnS) buffer layers. Shell Solar Industries provided high quality CIGSS absorber layers. The use of CBD-ZnS, which is a higher band gap material than CdS, improved the quantum efficiency of fabricated cells at lower wavelengths, leading to an increase in short circuit current. The best cell to date yielded an active area (0.43 cm 2 ) efficiency of 13.3%. The effect of the ZnS buffer layer thickness on device performance was studied carefully. This paper also presents a discussion of issues relevant to the use of the CBD-ZnS buffer material for improving device performance

  3. Efficient cold cathode emission in crystalline-amorphous hybrid: Study on carbon nanotube-cadmium selenide system

    Science.gov (United States)

    Sarkar, S.; Banerjee, D.; Das, N. S.; Ghorai, U. K.; Sen, D.; Chattopadhyay, K. K.

    2018-03-01

    Cadmium Selenide (CdSe) quantum dot (QD) decorated amorphous carbon nanotubes (a-CNTs) hybrids have been synthesized by simple chemical process. The samples were characterized by field emission scanning and transmission electron microscopy, Fourier transformed infrared spectroscopy, Raman and UV-Vis spectroscopy. Lattice image obtained from transmission electron microscopic study confirms the successful attachment of CdSe QDs. It is seen that hybrid samples show an enhanced cold emission properties with good stability. The results have been explained in terms of increased roughness, more numbers of emitting sites and favorable band bending induced electron transport. ANSYS software based calculation has also supported the result. Also a first principle based study has been done which shows that due to the formation of hybrid structure there is a profound upward shift in the Fermi level, i.e. a decrease of work function, which is believed to be another key reason for the observed improved field emission performance.

  4. Low-energy electron energy losses and inelastic mean free paths in zinc, selenium, and zinc selenide

    Energy Technology Data Exchange (ETDEWEB)

    Bourke, J.D.; Chantler, C.T., E-mail: chantler@unimelb.edu.au

    2014-10-15

    We compute low-energy optical energy loss spectra for the elemental solids zinc and selenium, and for the binary compound zinc selenide. The optical data are transformed via a constrained partial-pole algorithm to produce momentum-dependent electron energy loss spectra and electron inelastic mean free paths. This enables a comparison between the electron scattering behaviour in a compound solid and its constituent elements. Results cannot be explained by aggregation methods or commonly used universal curves, and prove that new approaches are required. Our work demonstrates new capabilities for the determination of fundamental material properties for a range of structures previously inaccessible to established theoretical models, and at energy levels inaccessible to most experimental techniques.

  5. Low-energy electron energy losses and inelastic mean free paths in zinc, selenium, and zinc selenide

    International Nuclear Information System (INIS)

    Bourke, J.D.; Chantler, C.T.

    2014-01-01

    We compute low-energy optical energy loss spectra for the elemental solids zinc and selenium, and for the binary compound zinc selenide. The optical data are transformed via a constrained partial-pole algorithm to produce momentum-dependent electron energy loss spectra and electron inelastic mean free paths. This enables a comparison between the electron scattering behaviour in a compound solid and its constituent elements. Results cannot be explained by aggregation methods or commonly used universal curves, and prove that new approaches are required. Our work demonstrates new capabilities for the determination of fundamental material properties for a range of structures previously inaccessible to established theoretical models, and at energy levels inaccessible to most experimental techniques

  6. Ecotoxicological assessment of solar cell leachates: Copper indium gallium selenide (CIGS) cells show higher activity than organic photovoltaic (OPV) cells

    Energy Technology Data Exchange (ETDEWEB)

    Brun, Nadja Rebecca [University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz (Switzerland); Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Universitätsstrasse 16, CH-8092 Zürich (Switzerland); Wehrli, Bernhard [Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Universitätsstrasse 16, CH-8092 Zürich (Switzerland); Fent, Karl, E-mail: karl.fent@fhnw.ch [University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz (Switzerland); Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Universitätsstrasse 16, CH-8092 Zürich (Switzerland)

    2016-02-01

    Despite the increasing use of photovoltaics their potential environmental risks are poorly understood. Here, we compared ecotoxicological effects of two thin-film photovoltaics: established copper indium gallium selenide (CIGS) and organic photovoltaic (OPV) cells. Leachates were produced by exposing photovoltaics to UV light, physical damage, and exposure to environmentally relevant model waters, representing mesotrophic lake water, acidic rain, and seawater. CIGS cell leachates contained 583 μg L{sup −1} molybdenum at lake water, whereas at acidic rain and seawater conditions, iron, copper, zinc, molybdenum, cadmium, silver, and tin were present up to 7219 μg L{sup −1}. From OPV, copper (14 μg L{sup −1}), zinc (87 μg L{sup −1}) and silver (78 μg L{sup −1}) leached. Zebrafish embryos were exposed until 120 h post-fertilization to these extracts. CIGS leachates produced under acidic rain, as well as CIGS and OPV leachates produced under seawater conditions resulted in a marked hatching delay and increase in heart edema. Depending on model water and solar cell, transcriptional alterations occurred in genes involved in oxidative stress (cat), hormonal activity (vtg1, ar), metallothionein (mt2), ER stress (bip, chop), and apoptosis (casp9). The effects were dependent on the concentrations of cationic metals in leachates. Addition of ethylenediaminetetraacetic acid protected zebrafish embryos from morphological and molecular effects. Our study suggests that metals leaching from damaged CIGS cells, may pose a potential environmental risk. - Highlights: • Photovoltaics may be disposed in the environment after usage. • Copper indium gallium selenide (CIGS) and organic (OPV) cells were compared. • Morphological and molecular effects were assessed in zebrafish embryos. • Environmental condition affected metal leaching and ecotoxicological activity. • Damaged CIGS cells pose higher risk to the environment than OPV cells.

  7. Single-molecule magnet behavior in an octanuclear dysprosium(iii) aggregate inherited from helical triangular Dy3 SMM-building blocks.

    Science.gov (United States)

    Zhang, Li; Zhang, Peng; Zhao, Lang; Wu, Jianfeng; Guo, Mei; Tang, Jinkui

    2016-06-28

    An unprecedented octanuclear dysprosium(iii) cluster with the formula [Dy8L6(μ3-OH)4(μ2-CH3O)2(CH3OH)6(H2O)2]·6H2O·10CH3OH·2CH3CN () based on a nonlinearly tritopic aroylhydrazone ligand H3L has been isolated, realizing the successful linking of pairwise interesting triangular Dy3 SMMs. It is noteworthy that two enantiomers (Λ and Δ configurations) individually behaving as a coordination-induced chirality presented in the Dy3 helicate are connected in the meso Dy8 cluster. Remarkably, alternating-current magnetic susceptibility measurements revealed that the Dy8 cluster shows typical SMM behavior inherited from its Dy3 helical precursor. It is one of the rare polynuclear Lnn SMMs (n > 7) under zero dc field.

  8. Study for the determination of samarium, europium,terbium, dysprosium and yttrium in gadolinium oxide matrix by means of atomic absorption spectrophotometry using a graphite furnace

    International Nuclear Information System (INIS)

    Caires, A.C.F.

    1985-01-01

    A study for determination of samarium, europium, terbium, dysprosium and yttrium in a gadolinium oxide matrix by atomic absorption spectrophotometry using a graphite furnace is presented. The best charrring and atomization conditions were estabilished for each element, the most convenient ressonance lines being selected as well. The study was carried out for the mentioned lanthanides both when pure and when in binary mixtures with gadolinium, besides those where all for them were together with gadolinium. The determination limits for pure lanthanides were found to be between 1.3 and 9.6 ng assuming a 20% relative standard deviation as acceptable. The detection limits were in the range 0.51 and 7.5 ng, assuming as positive any answer higher than twofold the standard deviation. (author) [pt

  9. Synthesis and X-ray diffraction studies of dysprosium-calcium ferrites Dy1-xCaxFeO3-y (0≤x≤2/3)

    International Nuclear Information System (INIS)

    Li, J.; Song, D.; Su, Z.; Wang, T.M.

    1997-01-01

    Samples of dysprosium-calcium ferrites Dy 1-x Ca x FeO 3-y with x ranging from 0 to 2/3 were novelly prepared in air by solid state reaction and characterized by X-ray powder diffraction. These samples are single-phased orthorhombic perovskite-type compounds belonging to the space group D 2h 16 -Pbnm. The lattice constants of the Dy 1-x Ca x FeO 3-y samples have been refined by Cohen's least-squares method. The initial substitution of Ca for Dy leads to a decrease of the lattice constants. Further substitution of Ca for Dy has hardly any influence on the lattice dimensions. (orig.)

  10. Investigation of deep level defects in epitaxial semiconducting zinc sulpho-selenide. Progress report, 15 June 1979-14 June 1980

    International Nuclear Information System (INIS)

    Wessels, B.W.

    1980-01-01

    In an effort to understand the defect structure of the ternary II-VI compound zinc sulpho-selenide, the binary compound zinc selenide was investigated. Thin single crystalline films of zinc selenide were heteroepitaxially grown on (100) GaAs. Epitaxial layers from 5 to 50 microns thick could be readily grown using a chemical vapor transport technique. The layers had an excellent morphology with few stacking faults and hillocks. Detailed epitaxial growth kinetics were examined as a function of temperature and reactant concentration. It was found that hydrogen flow rate, source and substrate temperature affect the growth rate of the epitaxial films. Au - ZnSe Schottky barrier diodes and ZnSe - GaAs n-p heterojunctions were prepared from the epitaxial layers. Current-voltage characteristics were measured on both types of diodes. From capacitance-voltage measurements the residual doping density of the epitaxial layers were found to be of the order of 10 14 - 10 15 cm -3 . Finally, we have begun to measure the deep level spectrum of both the Schottky barrier diodes and the heterojunctions. Deep level transient spectroscopy appears to be well suited for determining trapping states in ZnSe provided the material has a low enough resistivity

  11. Exploring the thermoelectric and magnetic properties of uranium selenides: Tl2Ag2USe4 and Tl3Cu4USe6

    International Nuclear Information System (INIS)

    Azam, Sikander; Khan, Saleem Ayaz; Din, Haleem Ud; Khenata, Rabah; Goumri-Said, Souraya

    2016-01-01

    The electronic, magnetic and thermoelectric properties of Tl 2 Ag 2 USe 4 and Tl 3 Cu 4 USe 6 compounds were investigated using the full potential linear augmented plane wave (FP-LAPW) method based on the density functional theory (DFT). The exchange correlation was treated with the generalized gradient approximation plus optimized effective Hubbard parameter and spin–orbit coupling (GGA+U+SOC). The present uranium selenides show narrow direct energy band gap values of 0.7 and 0.875 eV for Tl 2 Ag 2 USe 4 and Tl 3 Cu 4 USe 6 respectively. For both selenides U-d/f states are responsible for electrical transport properties. Uranium atoms were the most contributors in the magnetic moment compared to other atoms and show ferromagnetic nature. The spin density isosurfaces show the polarization of neighboring atoms of Uranium, such as silver/copper and selenium. Thermoelectric calculations reveal that Tl 3 Cu 4 USe 6 is more suitable for thermoelectric device applications than Tl 2 Ag 2 USe 4 . - Highlights: • Electronic, magnetic and thermoelectric properties of uranium selenides are investigated with DFT. • They show a narrow direct energy band gap of 0.7 and 0.875 eV. • U-d/f states are responsible for electrical transport properties. • Tl 3 Cu 4 USe 6 is more suitable for thermoelectric device applications than Tl 2 Ag 2 USe 4 .

  12. Study of the crystallographic phase change on copper (I) selenide thin films prepared through chemical bath deposition by varying the pH of the solution

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval-Paz, M.G., E-mail: myrnasandoval@udec.cl [Departament of Physics, Faculty of Physical Sciences and Mathematics, University of Concepcion, Box 160-C, Concepción (Chile); Rodríguez, C.A. [Department of Materials Engineering, Faculty of Engineering, University of Concepción, Edmundo Larenas 270, Concepción 4070409 (Chile); Porcile-Saavedra, P.F. [Departament of Physics, Faculty of Physical Sciences and Mathematics, University of Concepcion, Box 160-C, Concepción (Chile); Trejo-Cruz, C. [Department of Physics, Faculty of Science, University of Biobío, Avenue Collao 1202, Box 5C, Concepción 4051381 (Chile)

    2016-07-15

    Copper (I) selenide thin films with orthorhombic and cubic structure were deposited on glass substrates by using the chemical bath deposition technique. The effects of the solution pH on the films growth and subsequently the structural, optical and electrical properties of the films were studied. Films with orthorhombic structure were obtained from baths wherein both metal complex and hydroxide coexist; while films with cubic structure were obtained from baths where the metal hydroxide there is no present. The structural modifications are accompanied by changes in bandgap energy, morphology and electrical resistivity of the films. - Graphical abstract: “Study of the crystallographic phase change on copper (I) selenide thin films prepared through chemical bath deposition by varying the pH of the solution” by M. G. Sandoval-Paz, C. A. Rodríguez, P. F. Porcile-Saavedra, C. Trejo-Cruz. Display Omitted - Highlights: • Copper (I) selenide thin films were obtained by chemical bath deposition. • Orthorhombic to cubic phase change was induced by varying the reaction solution pH. • Orthorhombic phase is obtained mainly from a hydroxides cluster mechanism. • Cubic phase is obtained mainly from an ion by ion mechanism. • Structural, optical and electrical properties are presented as a function of pH.

  13. Facile hot-injection synthesis of stoichiometric Cu2ZnSnSe4 nanocrystals using bis(triethylsilyl) selenide.

    Science.gov (United States)

    Jin, Chunyu; Ramasamy, Parthiban; Kim, Jinkwon

    2014-07-07

    Cu2ZnSnSe4 is a prospective material as an absorber in thin film solar cells due to its many advantages including direct band gap, high absorption coefficient, low toxicity, and relative abundance (indium-free) of its elements. In this report, CZTSe nanoparticles have been synthesized by the hot-injection method using bis-(triethylsilyl)selenide [(Et3Si)2Se] as the selenium source for the first time. Energy dispersive X-ray spectroscopy (EDS) confirmed the stoichiometry of CZTSe nanoparticles. X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies showed that the nanocrystals were single phase polycrystalline with their size within the range of 25-30 nm. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy measurements ruled out the existence of secondary phases such as Cu2SnSe3 and ZnSe. The effect of reaction time and precursor injection order on the formation of stoichiometric CZTSe nanoparticles has been studied by Raman spectroscopy. UV-vis-NIR data indicate that the CZTSe nanocrystals have an optical band gap of 1.59 eV, which is optimal for photovoltaic applications.

  14. Engineering phase transformation of cobalt selenide in carbon cages and the phases’ bifunctional electrocatalytic activity for water splitting

    Science.gov (United States)

    Gao, Jiaojiao; Liu, Li; Qiu, Hua-Jun; Wang, Yu

    2017-08-01

    Using Co-based metal-organic frameworks as the precursor, we synthesized cobalt selenide (CoSe2) nanoparticles imbedded in carbon cages. By simply controlling the annealing conditions, phase transformation of CoSe2 from the orthorhombic phase to the cubic phase has been realized. Benefitting from the metallic character, the cubic phase CoSe2 shows greatly enhanced electrocatalytic activity for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). The as-prepared cubic phase CoSe2 electrode possesses onset overpotentials of 43 and 200 mV, and Tafel slopes of 51 and 83 mV dec-1 for HER and OER, respectively, which are remarkably superior to that of the orthorhombic phase CoSe2 catalyst and comparable to those of commercial noble-metal catalysts. In addition, the cubic phase CoSe2 electrode also demonstrates excellent stability after long-term operations. Our work not only provides a high performance catalyst for water splitting, but also introduces a new route to the design of a highly efficient catalyst by phase transformation.

  15. Aspects of a Distinct Cytotoxicity of Selenium Salts and Organic Selenides in Living Cells with Possible Implications for Drug Design

    Directory of Open Access Journals (Sweden)

    Ethiene Castellucci Estevam

    2015-07-01

    Full Text Available Selenium is traditionally considered as an antioxidant element and selenium compounds are often discussed in the context of chemoprevention and therapy. Recent studies, however, have revealed a rather more colorful and diverse biological action of selenium-based compounds, including the modulation of the intracellular redox homeostasis and an often selective interference with regulatory cellular pathways. Our basic activity and mode of action studies with simple selenium and tellurium salts in different strains of Staphylococcus aureus (MRSA and Saccharomyces cerevisiae indicate that such compounds are sometimes not particularly toxic on their own, yet enhance the antibacterial potential of known antibiotics, possibly via the bioreductive formation of insoluble elemental deposits. Whilst the selenium and tellurium compounds tested do not necessarily act via the generation of Reactive Oxygen Species (ROS, they seem to interfere with various cellular pathways, including a possible inhibition of the proteasome and hindrance of DNA repair. Here, organic selenides are considerably more active compared to simple salts. The interference of selenium (and tellurium compounds with multiple targets could provide new avenues for the development of effective antibiotic and anticancer agents which may go well beyond the traditional notion of selenium as a simple antioxidant.

  16. Iron selenide films by aerosol assisted chemical vapor deposition from single source organometallic precursor in the presence of surfactants

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, Raja Azadar [Department of Chemistry, Quaid-i-Azam University, 45320 Islamabad (Pakistan); Badshah, Amin, E-mail: aminbadshah@yahoo.com [Department of Chemistry, Quaid-i-Azam University, 45320 Islamabad (Pakistan); Younis, Adnan [School of Materials Science and Engineering, University of New South Wales, Sydney 2052, NSW (Australia); Khan, Malik Dilshad [Department of Chemistry, Quaid-i-Azam University, 45320 Islamabad (Pakistan); Akhtar, Javeed [Department of Physics, COMSATS Institute of Information Technology, Park Road, Chak Shahzad, Islamabad (Pakistan)

    2014-09-30

    This article presents the synthesis and characterization (multinuclear nuclear magnetic resonance, Fourier transform infrared spectroscopy, carbon–hydrogen–nitrogen–sulfur analyzer, atomic absorption spectrometry and thermogravimetric analysis) of a single source organometallic precursor namely 1-acetyl-3-(4-ferrocenylphenyl)selenourea for the fabrication of iron selenide (FeSe) films on glass substrates using aerosol assisted chemical vapor deposition (AACVD). The changes in the morphologies of the films have been monitored by the use of two different surfactants i.e. triton X-100 and tetraoctylphosphonium bromide during AACVD. The role of surfactant has been evaluated by examining the interaction of the surfactants with the precursor by using UV–vis spectroscopy and cyclic voltammetry. The fabricated FeSe films have been characterized with powder X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. - Highlights: • Ferrocene incorporated selenourea (FIS) has been synthesized and characterized. • FeSe thin films have been fabricated from FIS. • Mechanism of film growth was studied with cyclic voltammetry and UV–vis spectroscopy.

  17. Influence of growth and photocatalytic properties of copper selenide (CuSe) nanoparticles using reflux condensation method

    Energy Technology Data Exchange (ETDEWEB)

    Sonia, S. [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641046 (India); Kumar, P. Suresh [Thin Film and Nanomaterials Laboratory, Department of Physics, Bharathiar University, Coimbatore 641046 (India); Mangalaraj, D., E-mail: dmraj800@yahoo.com [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641046 (India); Ponpandian, N.; Viswanathan, C. [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641046 (India)

    2013-10-15

    Influence of reaction conditions on the synthesis of copper selenide (CuSe) nanoparticles and their photo degradation activity is studied. Nearly monodispersed uniform size (23–44 nm) nanoparticles are synthesized by varying the reaction conditions using reflux condensation method. The obtained nanoparticles are characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy and UV–visible absorption spectroscopy. The X-ray diffraction analysis of the sample shows the formation of nanoparticles with hexagonal CuSe structure. The result indicates that on increasing the reaction time from 4 to 12 h, the particle size decreases from 44 to 23 nm, but an increase in the reaction temperature increases the particle size. The calculated band gap E{sub g} is ranging from 2.34 to 3.05 eV which is blue shifted from the bulk CuSe (2.2 eV). The photocatalytic degradation efficiency of the CuSe nanoparticles on two organic dyes Methylene blue (MB) and Rhodamine-B (RhB) in aqueous solution under UV region is calculated as 76 and 87% respectively.

  18. Remarkable photo-catalytic degradation of malachite green by nickel doped bismuth selenide under visible light irradiation

    Science.gov (United States)

    Kulsi, Chiranjit; Ghosh, Amrita; Mondal, Anup; Kargupta, Kajari; Ganguly, Saibal; Banerjee, Dipali

    2017-01-01

    Bismuth selenide (Bi2Se3) and nickel (Ni) doped Bi2Se3 were prepared by a solvothermal approach to explore the photo-catalytic performance of the materials in degradation of malachite green (MG). The presence of nickel was confirmed by X-ray photoelectron spectroscopy (XPS) measurement in doped Bi2Se3. The results showed that the nickel doping played an important role in microstructure and photo-catalytic activity of the samples. Nickel doped Bi2Se3 sample exhibited higher photo-catalytic activity than that of the pure Bi2Se3 sample under visible-light irradiation. The photo-catalytic degradation followed first-order reaction kinetics. Fast degradation kinetics and complete (100% in 5 min of visible light irradiation) removal of MG was achieved by nickel doped Bi2Se3 in presence of hydrogen peroxide (H2O2) due to modification of band gap energies leading to suppression of photo-generated electron-hole recombination.

  19. Enhanced phosphorescence and electroluminescence in triplet emitters by doping gold into cadmium selenide/zinc sulfide nanoparticles

    International Nuclear Information System (INIS)

    Liu, H.-W.; Laskar, Inamur R.; Huang, C.-P.; Cheng, J.-A.; Cheng, S.-S.; Luo, L.-Y.; Wang, H.-R.; Chen, T.-M.

    2005-01-01

    Gold-cadmium selenide/zinc sulfide (Au-CdSe/ZnS) nanocomposites (NCs) were synthesized and characterized by transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis, ultraviolet-visible (UV-visible) absorption and photoluminescence (PL) emission spectroscopy. The PL intensity in the Au-CdSe/ZnS NCs system was found to be much greater than that of CdSe/ZnS nanoparticles (NPs) alone, because of the surface-enhanced Raman scattering of Au NPs. Adding Au-CdSe/ZnS NCs to the cyclometalated iridium(III) complex (Ir-complex) greatly enhanced the PL intensity of a triplet emitter. Three double-layered electroluminescence (EL) devices were fabricated where the emitting zone contains the definite mixture of Ir-complex and the NCs [molar concentration of Ir-complex/NCs = 1:0 (Blank, D-1), 1:1 (D-2) and 1:3 (D-3)] and the device D-2 exhibited optimal EL performances

  20. MOF-derived Co-doped nickel selenide/C electrocatalysts supported on Ni foam for overall water splitting

    KAUST Repository

    Ming, Fangwang

    2016-09-01

    It is of prime importance to develop dual-functional electrocatalysts with good activity for overall water splitting, which remains a great challenge. Herein, we report the synthesis of a Co-doped nickel selenide (a mixture of NiSe and NiSe)/C hybrid nanostructure supported on Ni foam using a metal-organic framework as the precursor. The resulting catalyst exhibits excellent catalytic activity toward the oxygen evolution reaction (OER), which only requires an overpotential of 275 mV to drive a current density of 30 mA cm. This overpotential is much lower than those reported for precious metal free OER catalysts. The hybrid is also capable of catalyzing the hydrogen evolution reaction (HER) efficiently. A current density of -10 mA cm can be achieved at 90 mV. In addition, such a hybrid nanostructure can achieve 10 and 30 mA cm at potentials of 1.6 and 1.71 V, respectively, along with good durability when functioning as both the cathode and the anode for overall water splitting in basic media.

  1. MOF-derived Co-doped nickel selenide/C electrocatalysts supported on Ni foam for overall water splitting

    KAUST Repository

    Ming, Fangwang; Liang, Hanfeng; Shi, Huanhuan; Xu, Xun; Mei, Gui; Wang, Zhoucheng

    2016-01-01

    It is of prime importance to develop dual-functional electrocatalysts with good activity for overall water splitting, which remains a great challenge. Herein, we report the synthesis of a Co-doped nickel selenide (a mixture of NiSe and NiSe)/C hybrid nanostructure supported on Ni foam using a metal-organic framework as the precursor. The resulting catalyst exhibits excellent catalytic activity toward the oxygen evolution reaction (OER), which only requires an overpotential of 275 mV to drive a current density of 30 mA cm. This overpotential is much lower than those reported for precious metal free OER catalysts. The hybrid is also capable of catalyzing the hydrogen evolution reaction (HER) efficiently. A current density of -10 mA cm can be achieved at 90 mV. In addition, such a hybrid nanostructure can achieve 10 and 30 mA cm at potentials of 1.6 and 1.71 V, respectively, along with good durability when functioning as both the cathode and the anode for overall water splitting in basic media.

  2. Electrical and optical characteristics of heterojunction devices composed of silicon nanowires and mercury selenide nanoparticle films on flexible plastics.

    Science.gov (United States)

    Yeo, Minje; Yun, Junggwon; Kim, Sangsig

    2013-09-01

    A pn heterojunction device based on p-type silicon (Si) nanowires (NWs) prepared by top-down method and n-type mercury selenide (HgSe) nanoparticles (NPs) synthesized by the colloidal method have been fabricated on a flexible plastic substrate. The synthesized HgSe NPs were analyzed through the effective mass approximation. The characteristics of the heterojunction device were examined and studied with the energy band diagram. The device showed typical diode characteristics with a turn-on voltage of 1.5 V and exhibited a high rectification ratio of 10(3) under relatively low forward bias. Under illumination of 633-nm-wavelength light, the device presented photocurrent efficiency of 117.5 and 20.1 nA/W under forward bias and reverse bias conditions, respectively. Moreover, the photocurrent characteristics of the device have been determined by bending of the plastic substrate upward and downward with strain of 0.8%. Even though the photocurrent efficiency has fluctuations during the bending cycles, the values are roughly maintained for 10(4) bending cycles. This result indicates that the fabricated heterojunction device has the potential to be applied as fundamental elements of flexible nanoelectronics.

  3. Pulsed voltage deposited lead selenide thin film as efficient counter electrode for quantum-dot-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Bin Bin [Key Laboratory of Macromolecular Science of Shaanxi Province & School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710062 (China); Department of Chemical Engineering, Institute of Chemical Industry, Shaanxi Institute of Technology, Xi’an 710300 (China); Wang, Ye Feng [Key Laboratory of Macromolecular Science of Shaanxi Province & School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710062 (China); Wang, Xue Qing [Faculty of Chemical, Environmental and Biological Science and Technology, Dalian University of Technology, Dalian 116024 (China); Zeng, Jing Hui, E-mail: jhzeng@ustc.edu [Key Laboratory of Macromolecular Science of Shaanxi Province & School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710062 (China)

    2016-04-30

    Highlights: • PbSe thin film is deposited on FTO glass by a pulse voltage electrodeposition method. • The thin film is used as counter electrode (CE) in quantum dot-sensitized solar cell. • Superior electrocatalytic activity and stability in the polysulfide electrolyte is received. • The narrow band gap characteristics and p-type conductivity enhances the cell efficiency. • An efficiency of 4.67% is received for the CdS/CdSe co-sensitized solar cells. - Abstract: Lead selenide (PbSe) thin films were deposited on fluorine doped tin oxide (FTO) glass by a facile one-step pulse voltage electrodeposition method, and used as counter electrode (CE) in CdS/CdSe quantum dot-sensitized solar cells (QDSSCs). A power conversion efficiency of 4.67% is received for the CdS/CdSe co-sensitized solar cells, which is much better than that of 2.39% received using Pt CEs. The enhanced performance is attributed to the extended absorption in the near infrared region, superior electrocatalytic activity and p-type conductivity with a reflection of the incident light at the back electrode in addition. The physical and chemical properties were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS), reflectance spectra, electrochemical impedance spectroscopy (EIS) and Tafel polarization measurements. The present work provides a facile pathway to an efficient CE in the QDSSCs.

  4. Selenide isotope generator for the Galileo Mission: copper/water axially-grooved heat pipe topical report

    International Nuclear Information System (INIS)

    Strazza, N.P.

    1979-01-01

    This report presents a summary of the major accomplishments for the development, fabrication, and testing of axially-grooved copper/water heat pipes for Selenide Isotopic Generator (SIG) applications. The early development consisted of chemical, physical, and analytical studies to define an axially-grooved tube geometry that could be successfully fabricated and provide the desired long term (up to seven years) performance is presented. Heat pipe fabrication procedures, measured performance and accelerated life testing of heat pipes S/Ns AL-5 and LT-57 conducted at B and K Engineering are discussed. S/N AL-5 was the first axially-grooved copper/water heat pipe that was fabricated with the new internal coating process for cupric oxide (CuO) and the cleaning and water preparation methods developed by Battelle Columbus Laboratories. Heat pipe S/N LT-57 was fabricated along with sixty other axially-grooved heat pipes allocated for life testing at Teledyne Energy Systems. As of June 25, 1979, heat pipes S/Ns AL-5 and LT-57 have been accelerated life tested for 13,310 and 6,292 respectively, at a nominal operating temperature of 225 0 C without any signs of thermal performance degradation

  5. Ecotoxicological assessment of solar cell leachates: Copper indium gallium selenide (CIGS) cells show higher activity than organic photovoltaic (OPV) cells.

    Science.gov (United States)

    Brun, Nadja Rebecca; Wehrli, Bernhard; Fent, Karl

    2016-02-01

    Despite the increasing use of photovoltaics their potential environmental risks are poorly understood. Here, we compared ecotoxicological effects of two thin-film photovoltaics: established copper indium gallium selenide (CIGS) and organic photovoltaic (OPV) cells. Leachates were produced by exposing photovoltaics to UV light, physical damage, and exposure to environmentally relevant model waters, representing mesotrophic lake water, acidic rain, and seawater. CIGS cell leachates contained 583 μg L(-1) molybdenum at lake water, whereas at acidic rain and seawater conditions, iron, copper, zinc, molybdenum, cadmium, silver, and tin were present up to 7219 μg L(-1). From OPV, copper (14 μg L(-1)), zinc (87 μg L(-1)) and silver (78 μg L(-1)) leached. Zebrafish embryos were exposed until 120 h post-fertilization to these extracts. CIGS leachates produced under acidic rain, as well as CIGS and OPV leachates produced under seawater conditions resulted in a marked hatching delay and increase in heart edema. Depending on model water and solar cell, transcriptional alterations occurred in genes involved in oxidative stress (cat), hormonal activity (vtg1, ar), metallothionein (mt2), ER stress (bip, chop), and apoptosis (casp9). The effects were dependent on the concentrations of cationic metals in leachates. Addition of ethylenediaminetetraacetic acid protected zebrafish embryos from morphological and molecular effects. Our study suggests that metals leaching from damaged CIGS cells, may pose a potential environmental risk. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. X-Ray diffraction analysis of thermally evaporated copper tin selenide thin films at different annealing temperature

    International Nuclear Information System (INIS)

    Mohd Amirul Syafiq Mohd Yunos; Zainal Abidin Talib; Wan Mahmood Mat Yunus; Josephine Liew Ying Chyi; Wilfred Sylvester Paulus

    2010-01-01

    Semiconductor thin films Copper Tin Selenide, Cu 2 SnSe 3 , a potential compound for semiconductor radiation detector or solar cell applications were prepared by thermal evaporation method onto well-cleaned glass substrates. The as-deposited films were annealed in flowing purified nitrogen, N 2 , for 2 hours in the temperature range from 100 to 500 degree Celsius. The structure of as-deposited and annealed films has been studied by X-ray diffraction technique. The semi-quantitative analysis indicated from the Reitveld refinement show that the samples composed of Cu 2 SnSe 3 and SnSe. These studies revealed that the films were structured in mixed phase between cubic space group F-43 m (no. 216) and orthorhombic space group P n m a (no. 62). The crystallite size and lattice strain were determined from Scherrer calculation method. The results show that increasing in annealing temperature resulted in direct increase in crystallite size and decrease in lattice strain. (author)

  7. Influence of intramolecular f-f interactions on nuclear spin driven quantum tunneling of magnetizations in quadruple-decker phthalocyanine complexes containing two terbium or dysprosium magnetic centers.

    Science.gov (United States)

    Fukuda, Takamitsu; Matsumura, Kazuya; Ishikawa, Naoto

    2013-10-10

    Nuclear spin driven quantum tunneling of magnetization (QTM) phenomena, which arise from admixture of more than two orthogonal electronic spin wave functions through the couplings with those of the nuclear spins, are one of the important magnetic relaxation processes in lanthanide single molecule magnets (SMMs) in the low temperature range. Although recent experimental studies have indicated that the presence of the intramolecular f-f interactions affects their magnetic relaxation processes, little attention has been given to their mechanisms and, to the best of our knowledge, no rational theoretical models have been proposed for the interpretations of how the nuclear spin driven QTMs are influenced by the f-f interactions. Since quadruple-decker phthalocyanine complexes with two terbium or dysprosium ions as the magnetic centers show moderate f-f interactions, these are appropriate to investigate the influence of the f-f interactions on the dynamic magnetic relaxation processes. In the present paper, a theoretical model including ligand field (LF) potentials, hyperfine, nuclear quadrupole, magnetic dipolar, and the Zeeman interactions has been constructed to understand the roles of the nuclear spins for the QTM processes, and the resultant Zeeman plots are obtained. The ac susceptibility measurements of the magnetically diluted quadruple-decker monoterbium and diterbium phthalocyanine complexes, [Tb-Y] and [Tb-Tb], have indicated that the presence of the f-f interactions suppresses the QTMs in the absence of the external magnetic field (H(dc)) being consistent with previous reports. On the contrary, the faster magnetic relaxation processes are observed for [Tb-Tb] than [Tb-Y] at H(dc) = 1000 Oe, clearly demonstrating that the QTMs are rather enhanced in the presence of the external magnetic field. Based on the calculated Zeeman diagrams, these observations can be attributed to the enhanced nuclear spin driven QTMs for [Tb-Tb]. At the H(dc) higher than 2000 Oe, the

  8. Dual-mode T_1 and T_2 magnetic resonance imaging contrast agent based on ultrasmall mixed gadolinium-dysprosium oxide nanoparticles: synthesis, characterization, and in vivo application

    International Nuclear Information System (INIS)

    Tegafaw, Tirusew; Xu, Wenlong; Ahmad, Md Wasi; Lee, Gang Ho; Baeck, Jong Su; Chang, Yongmin; Bae, Ji Eun; Chae, Kwon Seok; Kim, Tae Jeong

    2015-01-01

    A new type of dual-mode T_1 and T_2 magnetic resonance imaging (MRI) contrast agent based on mixed lanthanide oxide nanoparticles was synthesized. Gd"3"+ ("8S_7_/_2) plays an important role in T_1 MRI contrast agents because of its large electron spin magnetic moment resulting from its seven unpaired 4f-electrons, and Dy"3"+ ("6H_1_5_/_2) has the potential to be used in T_2 MRI contrast agents because of its very large total electron magnetic moment: among lanthanide oxide nanoparticles, Dy_2O_3 nanoparticles have the largest magnetic moments at room temperature. Using these properties of Gd"3"+ and Dy"3"+ and their oxide nanoparticles, ultrasmall mixed gadolinium-dysprosium oxide (GDO) nanoparticles were synthesized and their potential to act as a dual-mode T_1 and T_2 MRI contrast agent was investigated in vitro and in vivo. The D-glucuronic acid coated GDO nanoparticles (d_a_v_g = 1.0 nm) showed large r_1 and r_2 values (r_2/r_1 ≈ 6.6) and as a result clear dose-dependent contrast enhancements in R_1 and R_2 map images. Finally, the dual-mode imaging capability of the nanoparticles was confirmed by obtaining in vivo T_1 and T_2 MR images. (paper)

  9. Extraction of Dysprosium Ions with DTPA Functionalized Superparamagnetic Nanoparticles Probed by Energy Dispersive X-ray Fluorescence and TEM/High-Angle Annular Dark Field Imaging.

    Science.gov (United States)

    Melo, Fernando Menegatti de; Almeida, Sabrina da Nobrega; Uezu, Noemi Saori; Ramirez, Carlos Alberto Ospina; Santos, Antonio Domingues Dos; Toma, Henrique Eisi

    2018-06-01

    The extraction of dysprosium (Dy3+) ions from aqueous solution was carried out successfully, using magnetite (Fe3O4) nanoparticles functionalized with diethylenetriaminepentaacetic acid (MagNP@DTPA). The process was monitored by energy dispersive X-ray fluorescence spectroscopy, as a function of concentration, proceeding according to a Langmuir isotherm with an equilibrium constant of 2.57 × 10-3 g(MagNP) L-1 and a saturation limit of 63.2 mgDy/gMagNP. The presence of paramagnetic Dy3+ ions attached to the superparamagnetic nanoparticles led to an overall decrease of magnetization. By imaging the nanoparticles surface using scanning transmission electron microscopy equipped with high resolution elemental analysis, it was possible to probe the binding of the Dy3+ ions to DTPA, and to show their distribution in a region of negative magnetic field gradients. This finding is coherent with the observed decrease of magnetization, associated with the antiferromagnetic coupling between the lanthanide ions and the Fe3O4 core.

  10. Transition-Metal-Free Diarylannulated Sulfide and Selenide Construction via Radical/Anion-Mediated Sulfur-Iodine and Selenium-Iodine Exchange.

    Science.gov (United States)

    Wang, Ming; Fan, Qiaoling; Jiang, Xuefeng

    2016-11-04

    A facile, straightforward protocol was established for diarylannulated sulfide and selenide construction through S-I and Se-I exchange without transition metal assistance. Elemental sulfur and selenium served as the chalcogen source. Diarylannulated sulfides were systematically achieved from a five- to eight-membered ring. A trisulfur radical anion was demonstrated as the initiator for this radical process via electron paramagnetic resonance (EPR) study. OFET molecules [1]benzothieno[3,2-b][1]benzothiophene (BTBT) and [1]benzothieno[3,2-b][1]benzoselenophene (BTBS) were efficiently established.

  11. {sup 77} Se NMR of deuteride vinyl and acetylene selenides; RMn de {sup 77} Se de selenetos vinilicos e acetilenicos deuterados

    Energy Technology Data Exchange (ETDEWEB)

    Roque, L C; Stefani, H A; Arruda Campos, I.P. de; Comasseto, J V [Sao Paulo Univ., SP (Brazil). Inst. de Quimica

    1992-12-31

    The main objective of this work is a contribution for establishing a data base sufficient for interpretation of the selenium organic compound spectra. Due to the short literature on acetylene and vinyl selenides, the investigation of these compounds using {sup 77} Se NMR has been considered interesting. Particularly, compounds containing the selenium phenyl group have been selected, as they are larger used in organic chemistry. Non usual deuterated compounds have been applied, viewing simplification of the experimental results interpretation, since the use of deuterium virtually eliminates the Se-H coupling constants, due to the protons of the selenium phenyl group 5 refs., 2 tabs.

  12. Transition from Sign-Reversed to Sign-Preserved Cooper-Pairing Symmetry in Sulfur-Doped Iron Selenide Superconductors.

    Science.gov (United States)

    Wang, Qisi; Park, J T; Feng, Yu; Shen, Yao; Hao, Yiqing; Pan, Bingying; Lynn, J W; Ivanov, A; Chi, Songxue; Matsuda, M; Cao, Huibo; Birgeneau, R J; Efremov, D V; Zhao, Jun

    2016-05-13

    An essential step toward elucidating the mechanism of superconductivity is to determine the sign or phase of the superconducting order parameter, as it is closely related to the pairing interaction. In conventional superconductors, the electron-phonon interaction induces attraction between electrons near the Fermi energy and results in a sign-preserved s-wave pairing. For high-temperature superconductors, including cuprates and iron-based superconductors, prevalent weak coupling theories suggest that the electron pairing is mediated by spin fluctuations which lead to repulsive interactions, and therefore that a sign-reversed pairing with an s_{±} or d-wave symmetry is favored. Here, by using magnetic neutron scattering, a phase sensitive probe of the superconducting gap, we report the observation of a transition from the sign-reversed to sign-preserved Cooper-pairing symmetry with insignificant changes in T_{c} in the S-doped iron selenide superconductors K_{x}Fe_{2-y}(Se_{1-z}S_{z})_{2}. We show that a rather sharp magnetic resonant mode well below the superconducting gap (2Δ) in the undoped sample (z=0) is replaced by a broad hump structure above 2Δ under 50% S doping. These results cannot be readily explained by simple spin fluctuation-exchange pairing theories and, therefore, multiple pairing channels are required to describe superconductivity in this system. Our findings may also yield a simple explanation for the sometimes contradictory data on the sign of the superconducting order parameter in iron-based materials.

  13. Polyamide–thallium selenide composite materials via temperature and pH controlled adsorption–diffusion method

    Energy Technology Data Exchange (ETDEWEB)

    Ivanauskas, Remigijus; Samardokas, Linas [Department of Physical and Inorganic Chemistry, Kaunas University of Technology, Radvilenu str. 19, Kaunas LT-50254 (Lithuania); Mikolajunas, Marius; Virzonis, Darius [Department of Technology, Kaunas University of Technology, Panevezys Faculty, Daukanto 12, 35212 Panevezys (Lithuania); Baltrusaitis, Jonas, E-mail: job314@lehigh.edu [Department of Chemical and Biomolecular Engineering, Lehigh University, B336 Iacocca Hall, 111 Research Drive, Bethlehem, PA 18015 (United States)

    2014-10-30

    Graphical abstract: Single phase polyamide–thallium selenide hybrid functional materials were synthesized for solar energy conversion. - Highlights: • Thallium selenide–polyamide composite materials surfaces synthesized. • Mixed phase composition confirmed by XRD. • Increased temperature resulted in a denser surface packing. • Urbach energies correlated with AFM showing decreased structural disorder. • Annealing in N{sub 2} at 100 °C yielded a single TlSe phase. - Abstract: Composite materials based on III–VI elements are promising in designing efficient photoelectronic devices, such as thin film organic–inorganic solar cells. In this work, TlSe composite materials were synthesized on a model polymer polyamide using temperature and pH controlled adsorption–diffusion method via (a) selenization followed by (b) the exposure to the group III metal (Tl) salt solution and their surface morphological, chemical and crystalline phase information was determined with particular focus on their corresponding structure–optical property relationship. XRD analysis yielded a complex crystalline phase distribution which correlated well with the optical and surface morphological properties measured. pH 11.3 and 80 °C yielded well defined, low structural disorder composite material surface. After annealing in N{sub 2} at 100 °C, polycrystalline PA-Tl{sub x}Se{sub y} composite materials yielded a single TlSe phase due to the enhanced diffusion and reaction of thallium ions into the polymer. The method described here can be used to synthesize variety of binary III–VI compounds diffused into the polymer at relatively low temperatures and low overall cost, thus providing for a flexible synthesis route for novel composite solar energy harvesting materials.

  14. New quaternary thallium indium germanium selenide TlInGe2Se6: Crystal and electronic structure

    Science.gov (United States)

    Khyzhun, O. Y.; Parasyuk, O. V.; Tsisar, O. V.; Piskach, L. V.; Myronchuk, G. L.; Levytskyy, V. O.; Babizhetskyy, V. S.

    2017-10-01

    Crystal structure of a novel quaternary thallium indium germanium selenide TlInGe2Se6 was investigated by means of powder X-ray diffraction method. It was determined that the compound crystallizes in the trigonal space group R3 with the unit cell parameters a = 10.1798(2) Å, c = 9.2872(3) Å. The relationship with similar structures was discussed. The as-synthesized TlInGe2Se6 ingot was tested with X-ray photoelectron spectroscopy (XPS) and X-ray emission spectroscopy (XES). In particular, the XPS valence-band and core-level spectra were recorded for initial and Ar+ ion-bombarded surfaces of the sample under consideration. The XPS data allow for statement that the TlInGe2Se6 surface is rigid with respect to Ar+ ion-bombardment. Particularly, Ar+ ion-bombardment (3.0 keV, 5 min duration, ion current density fixed at 14 μA/cm2) did not cause substantial modifications of stoichiometry in topmost surface layers. Furthermore, comparison on a common energy scale of the XES Se Kβ2 and Ge Kβ2 bands and the XPS valence-band spectrum reveals that the principal contributions of the Se 4p and Ge 4p states occur in the upper and central portions of the valence band of TlInGe2Se6, respectively, with also their substantial contributions in other portions of the band. The bandgap energy of TlInGe2Se6 at the level of αg=103 cm-1 is equal to 2.38 eV at room temperature.

  15. Physical and biophysical assessment of highly fluorescent, magnetic quantum dots of a wurtzite-phase manganese selenide system

    Science.gov (United States)

    Sarma, Runjun; Das, Queen; Hussain, Anowar; Ramteke, Anand; Choudhury, Amarjyoti; Mohanta, Dambarudhar

    2014-07-01

    Combining fluorescence and magnetic features in a non-iron based, select type of quantum dots (QDs) can have immense value in cellular imaging, tagging and other nano-bio interface applications, including targeted drug delivery. Herein, we report on the colloidal synthesis and physical and biophysical assessment of wurtzite-type manganese selenide (MnSe) QDs in cell culture media. Aiming to provide a suitable colloidal system of biological relevance, different concentrations of reactants and ligands (e.g., thioglycolic acid, TGA) have been considered. The average size of the QDs is ˜7 nm, which exhibited a quantum yield of ˜75% as compared to rhodamine 6 G dye®. As revealed from time-resolved photoluminescence (TR-PL) response, the near band edge emission followed a bi-exponential decay feature with characteristic times of ˜0.64 ns and 3.04 ns. At room temperature, the QDs were found to exhibit paramagnetic features with coercivity and remanence impelled by TGA concentrations. With BSA as a dispersing agent, the QDs showed an improved optical stability in Dulbecco’s Modified Eagle Media® (DMEM) and Minimum Essential Media® (MEM), as compared to the Roswell Park Memorial Institute® (RPMI-1640) media. Finally, the cell viability of lymphocytes was found to be strongly influenced by the concentration of MnSe QDs, and had a safe limit upto 0.5 μM. With BSA inclusion in cell media, the cellular uptake of MnSe QDs was observed to be more prominent, as revealed from fluorescence imaging. The fabrication of water soluble, nontoxic MnSe QDs would open up an alternative strategy in nanobiotechnology, while preserving their luminescent and magnetic properties intact.

  16. Polyamide–thallium selenide composite materials via temperature and pH controlled adsorption–diffusion method

    International Nuclear Information System (INIS)

    Ivanauskas, Remigijus; Samardokas, Linas; Mikolajunas, Marius; Virzonis, Darius; Baltrusaitis, Jonas

    2014-01-01

    Graphical abstract: Single phase polyamide–thallium selenide hybrid functional materials were synthesized for solar energy conversion. - Highlights: • Thallium selenide–polyamide composite materials surfaces synthesized. • Mixed phase composition confirmed by XRD. • Increased temperature resulted in a denser surface packing. • Urbach energies correlated with AFM showing decreased structural disorder. • Annealing in N 2 at 100 °C yielded a single TlSe phase. - Abstract: Composite materials based on III–VI elements are promising in designing efficient photoelectronic devices, such as thin film organic–inorganic solar cells. In this work, TlSe composite materials were synthesized on a model polymer polyamide using temperature and pH controlled adsorption–diffusion method via (a) selenization followed by (b) the exposure to the group III metal (Tl) salt solution and their surface morphological, chemical and crystalline phase information was determined with particular focus on their corresponding structure–optical property relationship. XRD analysis yielded a complex crystalline phase distribution which correlated well with the optical and surface morphological properties measured. pH 11.3 and 80 °C yielded well defined, low structural disorder composite material surface. After annealing in N 2 at 100 °C, polycrystalline PA-Tl x Se y composite materials yielded a single TlSe phase due to the enhanced diffusion and reaction of thallium ions into the polymer. The method described here can be used to synthesize variety of binary III–VI compounds diffused into the polymer at relatively low temperatures and low overall cost, thus providing for a flexible synthesis route for novel composite solar energy harvesting materials

  17. Zr{sub 2}N{sub 2}Se. The first zirconium(IV) nitride selenide by the oxidation of zirconium(III) nitride with selenium

    Energy Technology Data Exchange (ETDEWEB)

    Lissner, Falk; Hack, Bettina; Schleid, Thomas [Institute for Inorganic Chemistry, University of Stuttgart (Germany); Lerch, Martin [Institute for Chemistry, Technical University of Berlin (Germany)

    2012-08-15

    The oxidation of zirconium(III) nitride (ZrN) with suitable amounts of selenium (Se) in the presence of sodium chloride (NaCl) as flux yields small yellow brownish platelets of the first zirconium(IV) nitride selenide with the composition Zr{sub 2}N{sub 2}Se. The new compound crystallizes in the hexagonal space group P6{sub 3}/mmc (no. 194) with a = 363.98(2) pm, c = 1316.41(9) pm (c/a = 3.617) and two formula units per unit cell. The crystallographically unique Zr{sup 4+} cations are surrounded by three selenide and four nitride anions in the shape of a capped trigonal antiprism. The Se{sup 2-} anions are coordinated by six Zr{sup 4+} cations as trigonal prism and the N{sup 3-} anions reside in tetrahedral surrounding of Zr{sup 4+} cations. These [NZr{sub 4}]{sup 13+} tetrahedra become interconnected via three edges each to form {sup 2}{sub ∞}{[(NZr_4_/_4)_2]"2"+} double layers parallel to the (001) plane, which are held together by monolayers of Se{sup 2-} anions. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Transport properties of Cu-doped bismuth selenide single crystals at high magnetic fields up to 60 Tesla: Shubnikov-de Haas oscillations and π-Berry phase

    Science.gov (United States)

    Romanova, Taisiia A.; Knyazev, Dmitry A.; Wang, Zhaosheng; Sadakov, Andrey V.; Prudkoglyad, Valery A.

    2018-05-01

    We report Shubnikov-de Haas (SdH) and Hall oscillations in Cu-doped high quality bismuth selenide single crystals. To increase the accuracy of Berry phase determination by means of the of the SdH oscillations phase analysis we present a study of n-type samples with bulk carrier density n ∼1019 -1020cm-3 at high magnetic field up to 60 Tesla. In particular, Landau level fan diagram starting from the value of the Landau index N = 4 was plotted. Thus, from our data we found π-Berry phase that directly indicates the Dirac nature of the carriers in three-dimensional topological insulator (3D TI) based on Cu-doped bismuth selenide. We argued that in our samples the magnetotransport is determined by a general group of carriers that exhibit quasi-two-dimensional (2D) behaviour and are characterized by topological π-Berry phase. Along with the main contribution to the conductivity the presence of a small group of bulk carriers was registered. For 3D-pocket Berry phase was identified as zero, which is a characteristic of trivial metallic states.

  19. Global use structures of the magnetic materials neodymium and dysprosium. A scenario-based analysis of the effect of the diffusion of electromobility on the demand for rare earths; Globale Verwendungsstrukturen der Magnetwerkstoffe Neodym und Dysprosium. Eine szenariobasierte Analyse der Auswirkung der Diffusion der Elektromobilitaet auf den Bedarf an Seltenen Erden

    Energy Technology Data Exchange (ETDEWEB)

    Gloeser-Chahoud, Simon; Kuehn, Andre; Tercero Espinoza, Luis

    2016-06-15

    Neodymium-iron-boron magnets (NdFeB) have experienced a significant demand as the most powerful permanent magnet in recent years, especially for the manufacture of compact electric servomotors with high efficiency and high power density, especially for mobile applications in hybrid traction motors and electric vehicles or for electric bikes. However, NdFeB magnets are also increasingly being used in general mechanical engineering (conveying and pumping systems, tools, air conditioning systems, lift motors, etc.), in the small electric motors of conventional passenger cars or in the generators of large wind power plants with permanent magnetic direct drive. Nevertheless, there is still high uncertainty in the use structures of NdFeB magnets and the contained rare earth elements neodymium and dysprosium. An effective instrument for increasing the market transparency and the understanding of complex anthropogenic material cycles is the dynamic material flow modeling. In the present work paper, this instrument is used for an in-depth analysis of the use structures of NdFeB magnets and the contained rare earths on a global scale. The dynamic modeling of product usage cycles reveals today's usage structures and quantifies future magnetic quantities in obsolete product flows. It could be shown that the magnets in today's scrap volume are mainly contained in obsolete electronics applications such as hard disks (HDD), CD and DVD drives, which makes the recycling hardly seem to be economical due to the small magnets and the high material spread, but in the foreseeable future with larger magnetic quantities from synchronous servomotors and generators can be expected, which significantly increases the recycling potential. In a further step, the effect of the diffusion of alternative drives in the automotive market on the dysprosium requirement is analyzed using a system dynamics model and possible adaptation mechanisms in the form of different substitution effects in

  20. Controlling Growth High Uniformity Indium Selenide (In2Se3) Nanowires via the Rapid Thermal Annealing Process at Low Temperature.

    Science.gov (United States)

    Hsu, Ya-Chu; Hung, Yu-Chen; Wang, Chiu-Yen

    2017-09-15

    High uniformity Au-catalyzed indium selenide (In 2 Se 3) nanowires are grown with the rapid thermal annealing (RTA) treatment via the vapor-liquid-solid (VLS) mechanism. The diameters of Au-catalyzed In 2 Se 3 nanowires could be controlled with varied thicknesses of Au films, and the uniformity of nanowires is improved via a fast pre-annealing rate, 100 °C/s. Comparing with the slower heating rate, 0.1 °C/s, the average diameters and distributions (standard deviation, SD) of In 2 Se 3 nanowires with and without the RTA process are 97.14 ± 22.95 nm (23.63%) and 119.06 ± 48.75 nm (40.95%), respectively. The in situ annealing TEM is used to study the effect of heating rate on the formation of Au nanoparticles from the as-deposited Au film. The results demonstrate that the average diameters and distributions of Au nanoparticles with and without the RTA process are 19.84 ± 5.96 nm (30.00%) and about 22.06 ± 9.00 nm (40.80%), respectively. It proves that the diameter size, distribution, and uniformity of Au-catalyzed In 2 Se 3 nanowires are reduced and improved via the RTA pre-treated. The systemic study could help to control the size distribution of other nanomaterials through tuning the annealing rate, temperatures of precursor, and growth substrate to control the size distribution of other nanomaterials. Graphical Abstract Rapid thermal annealing (RTA) process proved that it can uniform the size distribution of Au nanoparticles, and then it can be used to grow the high uniformity Au-catalyzed In 2 Se 3 nanowires via the vapor-liquid-solid (VLS) mechanism. Comparing with the general growth condition, the heating rate is slow, 0.1 °C/s, and the growth temperature is a relatively high growth temperature, > 650 °C. RTA pre-treated growth substrate can form smaller and uniform Au nanoparticles to react with the In 2 Se 3 vapor and produce the high uniformity In 2 Se 3 nanowires. The in situ annealing TEM is used to realize the effect of heating

  1. New Antimony Selenide/Nickel Oxide Photocathode Boosts the Efficiency of Graphene Quantum-Dot Co-Sensitized Solar Cells.

    Science.gov (United States)

    Kolay, Ankita; Kokal, Ramesh K; Kalluri, Ankarao; Macwan, Isaac; Patra, Prabir K; Ghosal, Partha; Deepa, Melepurath

    2017-10-11

    A novel assembly of a photocathode and a photoanode is investigated to explore their complementary effects in enhancing the photovoltaic performance of a quantum-dot solar cell (QDSC). While p-type nickel oxide (NiO) has been used previously, antimony selenide (Sb 2 Se 3 ) has not been used in a QDSC, especially as a component of a counter electrode (CE) architecture that doubles as the photocathode. Here, near-infrared (NIR) light-absorbing Sb 2 Se 3 nanoparticles (NPs) coated over electrodeposited NiO nanofibers on a carbon (C) fabric substrate was employed as the highly efficient photocathode. Quasi-spherical Sb 2 Se 3 NPs, with a band gap of 1.13 eV, upon illumination, release photoexcited electrons in addition to other charge carriers at the CE to further enhance the reduction of the oxidized polysulfide. The p-type conducting behavior of Sb 2 Se 3 , coupled with a work function at 4.63 eV, also facilitates electron injection to polysulfide. The effect of graphene quantum dots (GQDs) as co-sensitizers as well as electron conduits is also investigated in which a TiO 2 /CdS/GQDs photoanode structure in combination with a C-fabric CE delivered a power-conversion efficiency (PCE) of 5.28%, which is a vast improvement over the 4.23% that is obtained by using a TiO 2 /CdS photoanode (without GQDs) with the same CE. GQDs, due to a superior conductance, impact efficiency more than Sb 2 Se 3 NPs do. The best PCE of a TiO 2 /CdS/GQDs-nS 2- /S n 2- -Sb 2 Se 3 /NiO/C-fabric cell is 5.96% (0.11 cm 2 area), which, when replicated on a smaller area of 0.06 cm 2 , is seen to increase dramatically to 7.19%. The cell is also tested for 6 h of continuous irradiance. The rationalization for the channelized photogenerated electron movement, which augments the cell performance, is furnished in detail in these studies.

  2. Structure data of elements and intermetallic phases. SubVol. B. Sulfides, selenides, tellurides. Pt. 1. Ag-Al-Cd-S. Cu-Te-Yb

    Energy Technology Data Exchange (ETDEWEB)

    Hellwege, K H; Hellwege, A M [eds.; Eisenmann, B; Schaefer, H

    1986-01-01

    Volume III/14 'Structure data of elements and intermetallic phases' is a supplement to and extension of Volume III/6. Since the publication of III/6 in 1971 (considering original papers up to 1967), the amount of new information for these substances has increased rapidly. Therefore the data had to be divided into several parts. The first part, III/14b1, is presented herewith. In Volume III/6, simple sulfides, selenides and tellurides were treated together with the intermetallic phases. The data are compiled in the same way as in III/6: for each substance the space group, lattice constants, their dependence on temperature and pressure, and other information is listed in the tables. In several cases, mostly for solid solutions, diagrams are given which are added in a separate chapter. Original papers containing a complete structure analysis are referred to in the tables. (orig./GSCH).

  3. Coexistence of multiphase superconductivity and ferromagnetism in lithiated iron selenide hydroxide [(L i1 -xF ex) OH ]FeSe

    Science.gov (United States)

    Urban, Christian; Valmianski, Ilya; Pachmayr, Ursula; Basaran, Ali C.; Johrendt, Dirk; Schuller, Ivan K.

    2018-01-01

    We present experimental evidence for (a) multiphase superconductivity and (b) coexistence of magnetism and superconductivity in a single structural phase of lithiated iron selenide hydroxide [(L i1 -xF ex )OH]FeSe. Magnetic field modulated microwave spectroscopy data confirms superconductivity with at least two distinct transition temperatures attributed to well-defined superconducting phases at TSC 1=40 ±2 K and TSC 2=35 ±2 K. Magnetometry data for the upper critical fields reveal a change in the magnetic order (TM=12 K) below TSC 1 and TSC 2 that is consistent with ferromagnetism. This occurs because the superconducting coherence length is much smaller than the structural coherence length, allowing for several different electronic and magnetic states on a single crystallite. The results give insight into the physics of complex multinary materials, where several phenomena governed by different characteristic length scales coexist.

  4. Physical, optical and electrical properties of copper selenide (CuSe) thin films deposited by solution growth technique at room temperature

    International Nuclear Information System (INIS)

    Gosavi, S.R.; Deshpande, N.G.; Gudage, Y.G.; Sharma, Ramphal

    2008-01-01

    Copper selenide (CuSe) thin films are grown onto amorphous glass substrate from an aqueous alkaline medium using solution growth technique (SGT) at room temperature. The preparative parameters were optimized to obtain good quality of thin films. The as-deposited films were characterized for physical, optical and electrical properties. X-ray diffraction (XRD) pattern reveals that the films are polycrystalline in nature. Energy dispersive analysis by X-ray (EDAX) shows formation of stoichiometric CuSe compound. Uniform deposition of CuSe thin films on glass substrate was observed from scanning electron microscopy (SEM) and atomic force microscopy (AFM) micrographs. Average grain size was determined to 144.53 ± 10 nm using atomic force microscopy. The band gap was found to be 2.03 eV with direct band-to-band transition. Semi-conducting behaviour was observed from resistivity measurements. Ohmic behaviour was seen from I-V curve with good electrical conductivity

  5. A study on the optics of copper indium gallium (di)selenide (CIGS) solar cells with ultra-thin absorber layers.

    Science.gov (United States)

    Xu, Man; Wachters, Arthur J H; van Deelen, Joop; Mourad, Maurice C D; Buskens, Pascal J P

    2014-03-10

    We present a systematic study of the effect of variation of the zinc oxide (ZnO) and copper indium gallium (di)selenide (CIGS) layer thickness on the absorption characteristics of CIGS solar cells using a simulation program based on finite element method (FEM). We show that the absorption in the CIGS layer does not decrease monotonically with its layer thickness due to interference effects. Ergo, high precision is required in the CIGS production process, especially when using ultra-thin absorber layers, to accurately realize the required thickness of the ZnO, cadmium sulfide (CdS) and CIGS layer. We show that patterning the ZnO window layer can strongly suppress these interference effects allowing a higher tolerance in the production process.

  6. Design and fabrication of anti-reflection coating on Gallium Phosphide, Zinc Selenide and Zinc Sulfide substrates for visible and infrared application

    Directory of Open Access Journals (Sweden)

    Mokrý P.

    2013-05-01

    Full Text Available Results of design and fabrication of a dual-band anti-reflection coating on a gallium phosphide (GaP, zinc selenide (ZnSe and zinc sulfide (ZnS substrates are presented. A multilayer stack structure of antireflection coatings made of zinc sulfide and yttrium fluoride (YF3 was theoretically designed for optical bands between 0.8 and 0.9 μm and between 9.5 and 10.5 μm. This stack was designed as efficient for these materials (GaP, ZnS, ZnSe together. Multilayer stack structure was deposited using thermal evaporation method. Theoretically predicted transmittance spectra were compared with transmitted spectra measured on coated substrates. Efficiency of anti-reflection coating is estimated and discrepancies are analyzed and discussed.

  7. Layer Structured Bismuth Selenides of Bi2Se3 and Bi3Se4 for High Energy and Flexible All-Solid-State Micro-Supercapacitors.

    Science.gov (United States)

    Hao, Chunxue; Wang, Lidan; Wen, Fusheng; Xiang, Jianyong; Li, Lei; Hu, Wentao; Liu, Zhongyuan

    2017-12-20

    Bismuth selenides (Bi2Se3 and Bi3Se4), both of which have the layered rhombohedral crystal structure, and found to be useful as electrode materials for supercapacitor application in this work. Bi2Se3 nanoplates as electrode material exhibit much better performance than that of Bi3Se4 nanoparticles in liquid electrolyte system (6 M KOH), which delivers a higher specific capacitance (272.9 F/g) than that of Bi3Se4 (193.6 F/g) at 5 mV/s. This result would may be attributed to that Bi2Se3 nanoplates possess more active electrochemical surfaces for the reversible surface redox reactions owing to its planar quintuple stacked layers (septuple layers for Bi3Se4). For the demand of electronic skin, we used a novel flexible annular interdigital structure electrode applying for all-solid-state micro-supercapacitors (AMSCs). Bi2Se3 AMSCs device delivers a much more excellent supercapacitor performance, exhibits a large stack capacitance 89.5 F/cm3 (Bi3Se4: 79.1 F/cm3) at 20 mV/s, a high energy density 17.9 mWh/cm3 and high power density 18.9 W/cm3. The bismuth selenides also exhibit good cycle stability, retention 95.5% (90.3%) after 1000 c for Bi2Se3 (Bi3Se4). Obviously, Bi2Se3 nanoplates can be promising electrode materials for flexible annular interdigital all-solid-sate supercapacitor. © 2017 IOP Publishing Ltd.

  8. Layer structured bismuth selenides Bi2Se3 and Bi3Se4 for high energy and flexible all-solid-state micro-supercapacitors

    Science.gov (United States)

    Hao, Chunxue; Wang, Lidan; Wen, Fusheng; Xiang, Jianyong; Li, Lei; Hu, Wentao; Liu, Zhongyuan

    2018-02-01

    In this work, bismuth selenides (Bi2Se3 and Bi3Se4), both of which have a layered rhombohedral crystal structure, have been found to be useful as electrode materials for supercapacitor applications. In a liquid electrolyte system (6M KOH), Bi2Se3 nanoplates exhibit much better performance as an electrode material than Bi3Se4 nanoparticles do, delivering a higher specific capacitance (272.9 F g-1) than that of Bi3Se4 (193.6 F g-1) at 5 mV s-1. This result may be attributed to the fact that Bi2Se3 nanoplates possess more active electrochemical surfaces for the reversible surface redox reactions owing to their planar quintuple stacked layers (septuple layers for Bi3Se4). To meet the demands of electronic skin, we used a novel flexible annular interdigital structure electrode to support the all-solid-state micro-supercapacitors (AMSCs). The Bi2Se3 AMSC device delivers a much better supercapacitor performance, exhibits a large stack capacitance of 89.5 F cm-3 at 20 mV s-1 (Bi3Se4: 79.1 F cm-3), a high energy density of 17.9 mWh cm-3 and a high power density of 18.9 W cm-3. The bismuth selenides also exhibit good cycle stability, with 95.5% retention after 1000 c for Bi2Se3 (Bi3Se4:90.3%). Clearly, Bi2Se3 nanoplates can be promising electrode materials for flexible annular interdigital AMSCs.

  9. Synthesis and characterization of a family of structurally characterized dysprosium alkoxides for improved fatigue-resistance characteristics of PDyZT thin films.

    Science.gov (United States)

    Boyle, Timothy J; Bunge, Scott D; Clem, Paul G; Richardson, Jacob; Dawley, Jeffrey T; Ottley, Leigh Anna M; Rodriguez, Mark A; Tuttle, Bruce A; Avilucea, Gabriel R; Tissot, Ralph G

    2005-03-07

    Using either an ammoniacal route, the reaction between DyCl3, Na0, and HOR in liquid ammonia, or preferentially reacting Dy(N(SiMe3)2)3 with HOR in a solvent, we isolated a family of dysprosium alkoxides as [Dy(mu-ONep)2(ONep)]4 (1), (ONep)2Dy[(mu3-ONep)(mu-ONep)Dy(ONep)(THF)]2(mu-ONep) (2), (ONep)2Dy[(mu3-ONep)(mu-ONep)Dy(ONep)(py)]2(mu-ONep) (3), [Dy3(mu3-OBut)2(mu-OBut3(OBut)4(HOBut)2] (4), [Dy3(mu3-OBut)2(mu-OBut)3(OBut)4(THF)2] (5), [Dy3(mu3-OBut)2(mu-OBut)3(OBut)4(py)2] (6), (DMP)Dy(mu-DMP)4[Dy(DMP)2(NH3)]2 (7), [Dy(eta6-DMP)(DMP)2]2 (8), Dy(DMP)3(THF)3 (9), Dy(DMP)3(py)3 (10), Dy(DIP)3(NH3)2 (11), [Dy(eta6-DIP)(DIP)2]2 (12), Dy(DIP)3(THF)2 (13), Dy(DIP)3(py)3 (14), Dy(DBP)3(NH3) (15), Dy(DBP)3 (16), Dy(DBP)3(THF) (17), Dy(DBP)3(py)2 (18), [Dy(mu-TPS)(TPS2]2 (19), Dy(TPS)3(THF)3 (20), and Dy(TPS)3(py)3 (21), where ONep = OCH2CMe3, OBut) = OCMe3, DMP = OC6H3(Me)(2)-2,6, DIP = OC6H3(CHMe2)(2)-2,6, DBP = OC6H3(CMe3)(2)-2,6, TPS = OSi(C6H5)3, tol = toluene, THF = tetrahydrofuran, and py = pyridine. We were not able to obtain X-ray quality crystals of compounds 2, 8, and 9. The structures observed and data collected for the Dy compounds are consistent with those reported for its other congeners. A number of these precursors were used as Dy dopants in Pb(Zr0.3Ti0.7)O3 (PZT 30/70) thin films, with compound 12 yielding the highest-quality films. The resulting Pb0.94Dy0.04(Zr0.3Ti0.7)O3 [PDyZT (4/30/70)] had similar properties to PZT (30/70), but showed substantial resistance to polarization reversal fatigue.

  10. The role of dysprosium on the structural and magnetic properties of (Nd_1_−_xDy_x)_2Fe_1_4B nanoparticles

    International Nuclear Information System (INIS)

    Rahimi, Hamed; Ghasemi, Ali; Mozaffarinia, Reza; Tavoosi, Majid

    2017-01-01

    In current work, Nd2Fe14B nanoparticles was synthesized by sol-gel method. Dysprosium powders were added into Nd2Fe14B nanoparticles by mechanical alloying process in order to enhancement of coercivity. The phase analysis, structure, and magnetic properties of annealed (Nd_1_−_xDy_x)_2Fe_1_4B nanoparticles with different Dy-content (x=0.1, 0.2, 0.3, 0.4, 0.5, 0.6) were investigated by employing X-ray diffraction, X-ray photoelectron spectroscopy, energy dispersive spectroscopy, field emission scanning electron microscope, transmission electron microscope and vibrating sample magnetometer techniques. The results showed that with an increase in Dy amounts, the coercivity of particles increased from 2.9 kOe to 13.4 kOe and then decreased to 5.6 kOe. By adding an optimum amount of Dy (x=0.4), the coercivity was significantly increased from 2.9 kOe to 13.4 kOe. The average particle size of annealed (Nd_1_−_xDy_x)_2Fe_1_4B nanoparticles was below 10 nm. Magnetization reversal studies indicate that the coercivity of milled and annealed (Nd_1_−_xDy_x)_2Fe_1_4B nanoparticles is controlled by the nucleation of reversed magnetic domains. The experimental results in the angular dependence of coercivity for (Nd_1_−_xDy_x)_2Fe_1_4B permanent magnets showed that the normalized coercivity of the permanent magnets H_c(θ)/H_c(0) increases from 1 to about 1.2–1.5 with increasing θ from 0 to about π/3, for x=0.4–0.6. - Highlights: • Dy was added to Nd_2Fe_1_4B nanoparticles to improve the coercivity. • A maximum squareness ratio of 0.99 was obtained. • The average particle size decreased with an increase in Dy-content.

  11. Global use structures of the magnetic materials neodymium and dysprosium. A scenario-based analysis of the effect of the diffusion of electromobility on the demand for rare earths

    International Nuclear Information System (INIS)

    Gloeser-Chahoud, Simon; Kuehn, Andre; Tercero Espinoza, Luis

    2016-01-01

    Neodymium-iron-boron magnets (NdFeB) have experienced a significant demand as the most powerful permanent magnet in recent years, especially for the manufacture of compact electric servomotors with high efficiency and high power density, especially for mobile applications in hybrid traction motors and electric vehicles or for electric bikes. However, NdFeB magnets are also increasingly being used in general mechanical engineering (conveying and pumping systems, tools, air conditioning systems, lift motors, etc.), in the small electric motors of conventional passenger cars or in the generators of large wind power plants with permanent magnetic direct drive. Nevertheless, there is still high uncertainty in the use structures of NdFeB magnets and the contained rare earth elements neodymium and dysprosium. An effective instrument for increasing the market transparency and the understanding of complex anthropogenic material cycles is the dynamic material flow modeling. In the present work paper, this instrument is used for an in-depth analysis of the use structures of NdFeB magnets and the contained rare earths on a global scale. The dynamic modeling of product usage cycles reveals today's usage structures and quantifies future magnetic quantities in obsolete product flows. It could be shown that the magnets in today's scrap volume are mainly contained in obsolete electronics applications such as hard disks (HDD), CD and DVD drives, which makes the recycling hardly seem to be economical due to the small magnets and the high material spread, but in the foreseeable future with larger magnetic quantities from synchronous servomotors and generators can be expected, which significantly increases the recycling potential. In a further step, the effect of the diffusion of alternative drives in the automotive market on the dysprosium requirement is analyzed using a system dynamics model and possible adaptation mechanisms in the form of different substitution effects in the

  12. Synthesis and characterization of (Ni{sub 1−x}Co{sub x})Se{sub 2} based ternary selenides as electrocatalyst for triiodide reduction in dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Theerthagiri, J.; Senthil, R.A. [Solar Energy Lab, Department of Chemistry, Thiruvalluvar University, Vellore 632115 (India); Buraidah, M.H. [Centre for Ionics University of Malaya, Department of Physics, University of Malaya, Kuala Lumpur 50603 (Malaysia); Raghavender, M. [Department of Physics, Yogi Vemana University, Kadapa 516003, Andhra Pradesh (India); Madhavan, J., E-mail: jagan.madhavan@gmail.com [Solar Energy Lab, Department of Chemistry, Thiruvalluvar University, Vellore 632115 (India); Arof, A.K. [Centre for Ionics University of Malaya, Department of Physics, University of Malaya, Kuala Lumpur 50603 (Malaysia)

    2016-06-15

    Ternary metal selenides of (Ni{sub 1−x}Co{sub x})Se{sub 2} with 0≤x≤1 were synthesized by using one-step hydrothermal reduction route. The synthesized metal selenides were utilized as an efficient, low-cost platinum free counter electrode for dye-sensitized solar cells. The cyclic voltammetry and electrochemical impedance spectroscopy studies revealed that the Ni{sub 0.5}Co{sub 0.5}Se{sub 2} counter electrode exhibited higher electrocatalytic activity and lower charge transfer resistance at the counter electrode/electrolyte interface than the other compositions for reduction of triiodide to iodide. Ternary selenides of Ni{sub 0.5}Co{sub 0.5}Se{sub 2} offer a synergistic effect to the electrocatalytic activity for the reduction of triiodide that might be due to an increase in active catalytic sites and small charge transfer resistance. The DSSC with Ni{sub 0.5}Co{sub 0.5}Se{sub 2} counter electrode achieved a high power conversion efficiency of 6.02%, which is comparable with that of conventional platinum counter electrode (6.11%). This present investigation demonstrates the potential application of Ni{sub 0.5}Co{sub 0.5}Se{sub 2} as counter electrode in dye-sensitized solar cells.

  13. Extension of the energy range of the experimental activation cross-sections data of longer-lived products of proton induced nuclear reactions on dysprosium up to 65MeV.

    Science.gov (United States)

    Tárkányi, F; Ditrói, F; Takács, S; Hermanne, A; Ignatyuk, A V

    2015-04-01

    Activation cross-sections data of longer-lived products of proton induced nuclear reactions on dysprosium were extended up to 65MeV by using stacked foil irradiation and gamma spectrometry experimental methods. Experimental cross-sections data for the formation of the radionuclides (159)Dy, (157)Dy, (155)Dy, (161)Tb, (160)Tb, (156)Tb, (155)Tb, (154m2)Tb, (154m1)Tb, (154g)Tb, (153)Tb, (152)Tb and (151)Tb are reported in the 36-65MeV energy range, and compared with an old dataset from 1964. The experimental data were also compared with the results of cross section calculations of the ALICE and EMPIRE nuclear model codes and of the TALYS nuclear reaction model code as listed in the latest on-line libraries TENDL 2013. Copyright © 2015. Published by Elsevier Ltd.

  14. Dysprosium doping induced shape and magnetic anisotropy of Fe{sub 3−x}Dy{sub x}O{sub 4} (x=0.01–0.1) nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Richa [School of Sciences, Indira Gandhi National Open University, Maidan Garhi, New Delhi 110068 (India); Department of Physics, ARSD college, University of Delhi, New Delhi 110021 (India); Luthra, Vandna [Department of Physics, Gargi College, Siri Fort Road, New Delhi 110049 (India); Gokhale, Shubha, E-mail: sgokhale@ignou.ac.in [School of Sciences, Indira Gandhi National Open University, Maidan Garhi, New Delhi 110068 (India)

    2016-09-15

    The effect of dysprosium doping on evolution of structural and magnetic properties of magnetite (Fe{sub 3}O{sub 4}) nanoparticles is reported. A standard route of co-precipitation was used for the synthesis of undoped and doped magnetite nanoparticles Fe{sub 3−x}Dy{sub x}O{sub 4} (x=0.0–0.1). Transmission electron microscopy (TEM) shows formation of round shaped particles with diameter in the range of 8–14 nm for undoped sample. On doping beyond x=0.01, the formation of rod like structures is initiated along with the round shaped particles. The number of rods is found to increase with increasing doping concentration. Magnetic characterization using Vibrating Sample Magnetometer (VSM) revealed doping dependent magnetic properties which can be correlated with the crystallite size as determined from X-ray diffraction (XRD). Enhancement in the saturation magnetization in the initial stages of doping can be explained on the basis of incorporation of Dy{sup 3+} ions in the inverse spinel structure at the octahedral site in place of Fe{sup 3+} ions. Subsequent decrease in saturation magnetization observed beyond x=0.03 could be attributed to precipitation of excess Dy in form of dysprosium ferrite phase. - Highlights: • Report on formation of nanorods in magnetite prompted by Dy doping. • Observation of anisotropic magnetic behaviour emanating from the shape anisotropy. • Evidence of Dy{sup 3+} ions occupying octahedral site in place of Fe{sup 3+} ions. • Nanorods envisaged to be useful as catalysts and in biomedical applications.

  15. Investigation of Electronic and Opto-Electronic Properties of Two-Dimensional (2D) Layers of Copper Indium Selenide Field Effect Transistors

    Science.gov (United States)

    Patil, Prasanna Dnyaneshwar

    Investigations performed in order to understand the electronic and optoelectronic properties of field effect transistors based on few layers of 2D Copper Indium Selenide (CuIn7Se11) are reported. In general, field effect transistors (FETs), electric double layer field effect transistors (EDL-FETs), and photodetectors are crucial part of several electronics based applications such as tele-communication, bio-sensing, and opto-electronic industry. After the discovery of graphene, several 2D semiconductor materials like TMDs (MoS2, WS2, and MoSe2 etc.), group III-VI materials (InSe, GaSe, and SnS2 etc.) are being studied rigorously in order to develop them as components in next generation FETs. Traditionally, thin films of ternary system of Copper Indium Selenide have been extensively studied and used in optoelectronics industry as photoactive component in solar cells. Thus, it is expected that atomically thin 2D layered structure of Copper Indium Selenide can have optical properties that could potentially be more advantageous than its thin film counterpart and could find use for developing next generation nano devices with utility in opto/nano electronics. Field effect transistors were fabricated using few-layers of CuIn7Se11 flakes, which were mechanically exfoliated from bulk crystals grown using chemical vapor transport technique. Our FET transport characterization measurements indicate n-type behavior with electron field effect mobility microFE ≈ 36 cm2 V-1 s-1 at room temperature when Silicon dioxide (SiO2) is used as a back gate. We found that in such back gated field effect transistor an on/off ratio of 104 and a subthreshold swing ≈ 1 V/dec can be obtained. Our investigations further indicate that Electronic performance of these materials can be increased significantly when gated from top using an ionic liquid electrolyte [1-Butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6)]. We found that electron field effect mobility microFE can be increased from

  16. Dysprosium selective potentiometric membrane sensor

    Energy Technology Data Exchange (ETDEWEB)

    Zamani, Hassan Ali, E-mail: haszamani@yahoo.com [Department of Applied Chemistry, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of); Faridbod, Farnoush; Ganjali, Mohammad Reza [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of)

    2013-03-01

    A novel Dy(III) ion-selective PVC membrane sensor was made using a new synthesized organic compound, 3,4-diamino-N Prime -((pyridin-2-yl)methylene)benzohydrazide (L) as an excellent sensing element. The electrode showed a Nernstian slope of 19.8 {+-} 0.6 mV per decade in a wide concentration range of 1.0 Multiplication-Sign 10{sup -6}-1.0 Multiplication-Sign 10{sup -2} mol L{sup -1}, a detection limit of 5.5 Multiplication-Sign 10{sup -7} mol L{sup -1}, a short conditioning time, a fast response time (< 10 s), and high selectivity towards Dy(III) ion in contrast to other cations. The proposed sensor was successfully used as an indicator electrode in the potentiometric titration of Dy(III) ions with EDTA. The membrane sensor was also applied to the F{sup -} ion indirect determination of some mouth washing solutions and to the Dy{sup 3+} determination in binary mixtures. Highlights: Black-Right-Pointing-Pointer The novelty of this work is based on the high affinity of the ionophore toward the Dy{sup 3+} ions. Black-Right-Pointing-Pointer This technique is very simple, fast and inexpensive and it is not necessary to use sophisticated equipment. Black-Right-Pointing-Pointer The newly developed sensor is superior to the formerly reported Dy{sup 3+} sensors in terms of selectivity.

  17. A study of the atmospherically important reactions between dimethyl selenide (DMSe) and molecular halogens (X2 = Cl2, Br2, and I2) with ab initio calculations.

    Science.gov (United States)

    Rhyman, Lydia; Armata, Nerina; Ramasami, Ponnadurai; Dyke, John M

    2012-06-14

    The atmospherically relevant reactions between dimethyl selenide (DMSe) and the molecular halogens (X(2) = Cl(2), Br(2), and I(2)) have been studied with ab initio calculations at the MP2/aug-cc-pVDZ level of theory. Geometry optimization calculations showed that the reactions proceed from the reagents to the products (CH(3)SeCH(2)X + HX) via three minima, a van der Waals adduct (DMSe:X(2)), a covalently bound intermediate (DMSeX(2)), and a product-like complex (CH(3)SeCH(2)X:HX). The computed potential energy surfaces are used to predict what molecular species are likely to be observed in spectroscopic experiments such as gas-phase photoelectron spectroscopy and infrared matrix isolation spectroscopy. It is concluded that, for the reactions of DMSe with Cl(2) and Br(2), the covalent intermediate should be seen in spectroscopic experiments, whereas, in the DMSe + I(2) reaction, the van der Waals adduct DMSe:I(2) should be observed. Comparison is made with previous related calculations and experiments on dimethyl sulfide (DMS) with molecular halogens. The relevance of the results to atmospheric chemistry is discussed. The DMSeX(2) and DMSe:X(2) intermediates are likely to be reservoirs of molecular halogens in the atmosphere which will lead on photolysis to ozone depletion.

  18. Zinc sulfide and zinc selenide immersion gratings for astronomical high-resolution spectroscopy: evaluation of internal attenuation of bulk materials in the short near-infrared region

    Science.gov (United States)

    Ikeda, Yuji; Kobayashi, Naoto; Kondo, Sohei; Yasui, Chikako; Kuzmenko, Paul J.; Tokoro, Hitoshi; Terada, Hiroshi

    2009-08-01

    We measure the internal attenuation of bulk crystals of chemical vapor deposition zinc selenide (CVD-ZnS), chemical vapor deposition zinc sulfide (CVD-ZnSe), Si, and GaAs in the short near-infrared (sNIR) region to evaluate the possibility of astronomical immersion gratings with those high refractive index materials. We confirm that multispectral grade CVD-ZnS and CVD-ZnSe are best suited for the immersion gratings, with the smallest internal attenuation of αatt=0.01 to 0.03 cm-1 among the major candidates. The measured attenuation is roughly in proportion to λ-2, suggesting it is dominated by bulk scattering due to the polycrystalline grains rather than by absorption. The total transmittance in the immersion grating is estimated to be at least >80%, even for the spectral resolution of R=300,000. Two potential problems, the scattered light by the bulk material and the degradation of the spectral resolution due to the gradient illumination in the diffracted beam, are investigated and found to be negligible for usual astronomical applications. Since the remaining problem, the difficulty of cutting grooves on CVD-ZnS and CVD-ZnSe, has recently been overcome by the nanoprecision fly-cutting technique, ZnS and ZnSe immersion gratings for astronomy can be technically realized.

  19. Effect of deposition temperature on the structural, morphological and optical band gap of lead selenide thin films synthesized by chemical bath deposition method

    Energy Technology Data Exchange (ETDEWEB)

    Hone, Fekadu Gashaw, E-mail: fekeye@gmail.com [Hawassa University, Department of Physics, Hawassa (Ethiopia); Ampong, Francis Kofi [Kwame Nkrumah University of Science and Technology, Department of Physics, Kumasi (Ghana)

    2016-11-01

    Lead selenide (PbSe) nanocrystalline thin films have been deposited on silica glass substrates by the chemical bath deposition technique. The samples were deposited at the bath temperatures of 60, 75 and 90 °C respectively and characterized by a variety of techniques. The XRD results revealed that the PbSe thin film deposited at 60 °C was amorphous in nature. Films deposited at higher temperatures exhibited sharp and intense diffraction peaks, indicating an improvement in crystallinety. The deposition temperature also had a strong influence on the preferred orientation of the crystallites as well as other structural parameters such as microstrain and dislocation density. From the SEM study it was observed that film deposited at 90 °C had well defined crystallites, uniformly distributed over the entire surface of the substrate. The EDAX study confirmed that the samples deposited at the higher temperature had a better stoichiometric ratio. The optical band gap varied from 2.26 eV to 1.13 eV with increasing deposition temperature. - Highlights: • The crystallinety of the films improved as the deposition temperature increased. • The deposition temperature strongly influenced the preferred orientations. • Microstrain and dislocation density are decreased linearly with deposition temperature. • Band gap decreased from 2.26 eV to 1.13 eV as the deposition temperature increased.

  20. In Situ Determination of Bisphenol A in Beverage Using a Molybdenum Selenide/Reduced Graphene Oxide Nanoparticle Composite Modified Glassy Carbon Electrode

    Directory of Open Access Journals (Sweden)

    Rongguang Shi

    2018-05-01

    Full Text Available Due to the endocrine disturbing effects of bisphenol A (BPA on organisms, rapid detection has become one of the most important techniques for monitoring its levels in the aqueous solutions associated with plastics and human beings. In this paper, a glassy carbon electrode (GCE modified with molybdenum selenide/reduced graphene oxide (MoSe2/rGO was fabricated for in situ determination of bisphenol A in several beverages. The surface area of the electrode dramatically increases due to the existence of ultra-thin nanosheets in a flower-like structure of MoSe2. Adding phosphotungstic acid in the electrolyte can significantly enhance the repeatability (RSD = 0.4% and reproducibility (RSD = 2.2% of the electrode. Under the optimized condition (pH = 6.5, the linear range of BPA was from 0.1 μM–100 μM and the detection limit was 0.015 μM (S/N = 3. When using the as-prepared electrode for analyzing BPA in beverage samples without any pretreatments, the recoveries ranged from 98–107%, and the concentrations were from below the detection limit to 1.7 μM, indicating its potential prospect for routine analysis of BPA.

  1. In Situ Determination of Bisphenol A in Beverage Using a Molybdenum Selenide/Reduced Graphene Oxide Nanoparticle Composite Modified Glassy Carbon Electrode.

    Science.gov (United States)

    Shi, Rongguang; Liang, Jing; Zhao, Zongshan; Liu, Yi; Liu, Aifeng

    2018-05-22

    Due to the endocrine disturbing effects of bisphenol A (BPA) on organisms, rapid detection has become one of the most important techniques for monitoring its levels in the aqueous solutions associated with plastics and human beings. In this paper, a glassy carbon electrode (GCE) modified with molybdenum selenide/reduced graphene oxide (MoSe₂/rGO) was fabricated for in situ determination of bisphenol A in several beverages. The surface area of the electrode dramatically increases due to the existence of ultra-thin nanosheets in a flower-like structure of MoSe₂. Adding phosphotungstic acid in the electrolyte can significantly enhance the repeatability (RSD = 0.4%) and reproducibility (RSD = 2.2%) of the electrode. Under the optimized condition (pH = 6.5), the linear range of BPA was from 0.1 μM⁻100 μM and the detection limit was 0.015 μM (S/ N = 3). When using the as-prepared electrode for analyzing BPA in beverage samples without any pretreatments, the recoveries ranged from 98⁻107%, and the concentrations were from below the detection limit to 1.7 μM, indicating its potential prospect for routine analysis of BPA.

  2. Dependence of Optical Properties of SEL-Deposited Silver Gallium Selenide Thin Films on the On-Line Growth Parameter: Annealing Duration

    International Nuclear Information System (INIS)

    Bhuiyan, M.R.A.; Firoz Hasan, S.M.

    2005-01-01

    Silver gallium selenide (AGS) composite thin films were formed onto ultrasonically and chemically cleaned glass substrates by successive on-line thermal evaporation of individual elements and post-deposition annealing at 300 0 C for various durations in vacuum. The annealing duration was varied between 5 and 20 minutes. The structural and optical properties of the films were ascertained by x-ray diffraction (XRD) and uv-vis-nir spectrophotometry (photon wavelength ranging between 300 and 2500 nm), respectively. The diffractogram indicated that these films were polycrystalline in nature having tetragonal structure with lattice parameters, a ∼ 6.0034 A and c ∼ 10.9165 A. The optical transmittance and reflectance were utilized to compute the absorption coefficient, refractive index and energy gap of the films. Dependence of the optical and structural properties of the films on various annealing durations has been analyzed. The nature of the optical transitions has been direct allowed with band gap energies ranging between 1.713 and 1.757 eV and refractive indices between 1.596 and 3.351 depending on photon energy as well as annealing duration. (authors)

  3. Exploring the thermoelectric and magnetic properties of uranium selenides: Tl{sub 2}Ag{sub 2}USe{sub 4} and Tl{sub 3}Cu{sub 4}USe{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Azam, Sikander; Khan, Saleem Ayaz [New Technologies – Research Center, University of West Bohemia, Univerzitni 8, 30614 Pilsen (Czech Republic); Din, Haleem Ud [Department of Physics, Hazara University, Mansehra (Pakistan); Khenata, Rabah [Laboratoire de Physique Quantique et de Modélisation Mathématique (LPQ3M), Département de Technologie, Université de Mascara, Mascara 29000 (Algeria); Goumri-Said, Souraya, E-mail: sosaid@alfaisal.edu [College of Science, Physics department, Alfaisal University, P.O. Box 50927, Riyadh 11533 (Saudi Arabia)

    2016-09-01

    The electronic, magnetic and thermoelectric properties of Tl{sub 2}Ag{sub 2}USe{sub 4} and Tl{sub 3}Cu{sub 4}USe{sub 6} compounds were investigated using the full potential linear augmented plane wave (FP-LAPW) method based on the density functional theory (DFT). The exchange correlation was treated with the generalized gradient approximation plus optimized effective Hubbard parameter and spin–orbit coupling (GGA+U+SOC). The present uranium selenides show narrow direct energy band gap values of 0.7 and 0.875 eV for Tl{sub 2}Ag{sub 2}USe{sub 4} and Tl{sub 3}Cu{sub 4}USe{sub 6} respectively. For both selenides U-d/f states are responsible for electrical transport properties. Uranium atoms were the most contributors in the magnetic moment compared to other atoms and show ferromagnetic nature. The spin density isosurfaces show the polarization of neighboring atoms of Uranium, such as silver/copper and selenium. Thermoelectric calculations reveal that Tl{sub 3}Cu{sub 4}USe{sub 6} is more suitable for thermoelectric device applications than Tl{sub 2}Ag{sub 2}USe{sub 4}. - Highlights: • Electronic, magnetic and thermoelectric properties of uranium selenides are investigated with DFT. • They show a narrow direct energy band gap of 0.7 and 0.875 eV. • U-d/f states are responsible for electrical transport properties. • Tl{sub 3}Cu{sub 4}USe{sub 6} is more suitable for thermoelectric device applications than Tl{sub 2}Ag{sub 2}USe{sub 4}.

  4. IR Laser-Induced Co-decomposition of Dimethyl Selenide and Trisilane: Gas-Phase Formation of SiSe and Chemical Vapor Deposition of Nanostructured H/Si/Se/C Polymers.

    Czech Academy of Sciences Publication Activity Database

    Santos, M.; Díaz, L.; Urbanová, Markéta; Bastl, Zdeněk; Šubrt, Jan; Pola, Josef

    2007-01-01

    Roč. 188, 2-3 (2007) , s. 399-408 ISSN 1010-6030 R&D Projects: GA MŠk(CZ) ME 846 Grant - others:MCyT(ES) BQU2003/08531/C02/02 Institutional research plan: CEZ:AV0Z40720504; CEZ:AV0Z40320502; CEZ:AV0Z40400503 Keywords : laser deposition * laser-induced polymers * silicon selenide Subject RIV: CH - Nuclear ; Quantum Chemistry Impact factor: 1.911, year: 2007

  5. An approach to global rovibrational analysis based on anharmonic ladder operators: Application to Hydrogen Selenide (H{sub 2}{sup 80}Se)

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez-Bajo, O. [Dpto. Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, 21071 Huelva (Spain); Carvajal, M., E-mail: miguel.carvajal@dfa.uhu.es [Dpto. Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, 21071 Huelva (Spain); Perez-Bernal, F. [Dpto. Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, 21071 Huelva (Spain)

    2012-01-02

    Graphical abstract: Schematic diagram of a bent triatomic molecule, depicting the atom numbering, and molecular axis system. An algebraic approach to perform global rovibrational analysis is presented. Highlights: Black-Right-Pointing-Pointer Novel approach for a global rovibrational analysis of polyatomic molecules spectra. Black-Right-Pointing-Pointer One-dimensional vibron model limit combined with rotational degrees of freedom. Black-Right-Pointing-Pointer Phase space Hamiltonian written in terms of anharmonic ladder operators. Black-Right-Pointing-Pointer Algebraic calculations performed with a symmetry-adapted rovibrational basis. Black-Right-Pointing-Pointer Description of the rovibrational spectrum of H{sub 2}Se in the ground electronic state. - Abstract: An algebraic approach to perform global rovibrational analysis of molecular spectra is presented. The approach combines the one-dimensional limit of the vibron model with rotational degrees of freedom. The model is based on the expression of the phase space Hamiltonian in terms of anharmonic ladder operators and the use of a symmetry-adapted basis set given by the linear combination of products of local vibrational and rotational wavefunctions. As an example we model the rovibrational spectra of a bent triatomic molecule, providing a global analysis for vibrational bands up to polyad 12 and J{sub max} = 5 of Hydrogen Selenide (H{sub 2}Se). Satisfactory fits of vibrational and rovibrational energies are obtained. A prediction of 2579 rovibrational energies up to J Less-Than-Or-Slanted-Equal-To 5 and polyad 12 for the 140 lowest vibrational bands is also obtained. A possible extension of the model to reach spectroscopic quality results in larger molecular systems is also given.

  6. Determination of the some electronic parameters of nanostructure copper selenide and Cu/Cu3Se2/n-GaAs/In structure

    International Nuclear Information System (INIS)

    Güzeldir, B.; Sağlam, M.; Ateş, A.; Türüt, A.

    2015-01-01

    Highlights: • Introducing to a new degree of freedom in the control of effective barrier height by using Cu. • We want to experimentally observe whether or not the diode continues the ideality in the temperature range of 60–400 K. • We have modified the Richardson’s plot using the temperature dependent values of effective area of the patches. - Abstract: The nanostructure copper selenide thin film has been grown on n-type gallium arsenide substrate by Successive Ionic Layer Adsorption and Reaction (SILAR) method. The film has been characterized by X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Atomic Force Microscope (AFM) measurements. X-ray diffraction analysis of the film confirms a polycrystalline with preferred orientation. The AFM and SEM micrographs of the film reveal smooth and uniform surface pattern without any dark pits, pinholes and microcracks. The Cu/Cu 3 Se 2 /n-GaAs/In structure has been thermally formed in evaporating system after the SILAR process. The electrical analysis of Cu/Cu 3 Se 2 /n-GaAs/In structure has been investigated by means of current–voltage (I–V) measurements in the temperature range of 60–400 K in dark conditions. The values of barrier height (BH) and ideality factor (n) ranged from 0.21 eV and 4.97 (60 K) to 0.83 eV and 1.14 (400 K), respectively. In the calculations, the electrical parameters of the experimental forward bias I–V characteristics of the Cu/Cu 3 Se 2 /n-GaAs/In with the homogeneity in the 60–400 K range have been explained by means of the thermionic emission (TE), considering Gaussian distribution (GD) of BH with linear bias dependence

  7. Determination of the some electronic parameters of nanostructure copper selenide and Cu/Cu{sub 3}Se{sub 2}/n-GaAs/In structure

    Energy Technology Data Exchange (ETDEWEB)

    Güzeldir, B.; Sağlam, M. [Department of Physics, Faculty of Sciences, Atatürk University, 25240 Erzurum (Turkey); Ateş, A. [Department of Material Engineering, Faculty of Engineering and Natural Sciences, Yıldırım Beyazıt University, Ankara (Turkey); Türüt, A. [Department of Physics Engineering, Faculty of Sciences, Istanbul Medeniyet University, 34000 Istanbul (Turkey)

    2015-04-05

    Highlights: • Introducing to a new degree of freedom in the control of effective barrier height by using Cu. • We want to experimentally observe whether or not the diode continues the ideality in the temperature range of 60–400 K. • We have modified the Richardson’s plot using the temperature dependent values of effective area of the patches. - Abstract: The nanostructure copper selenide thin film has been grown on n-type gallium arsenide substrate by Successive Ionic Layer Adsorption and Reaction (SILAR) method. The film has been characterized by X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Atomic Force Microscope (AFM) measurements. X-ray diffraction analysis of the film confirms a polycrystalline with preferred orientation. The AFM and SEM micrographs of the film reveal smooth and uniform surface pattern without any dark pits, pinholes and microcracks. The Cu/Cu{sub 3}Se{sub 2}/n-GaAs/In structure has been thermally formed in evaporating system after the SILAR process. The electrical analysis of Cu/Cu{sub 3}Se{sub 2}/n-GaAs/In structure has been investigated by means of current–voltage (I–V) measurements in the temperature range of 60–400 K in dark conditions. The values of barrier height (BH) and ideality factor (n) ranged from 0.21 eV and 4.97 (60 K) to 0.83 eV and 1.14 (400 K), respectively. In the calculations, the electrical parameters of the experimental forward bias I–V characteristics of the Cu/Cu{sub 3}Se{sub 2}/n-GaAs/In with the homogeneity in the 60–400 K range have been explained by means of the thermionic emission (TE), considering Gaussian distribution (GD) of BH with linear bias dependence.

  8. Formation of CuInSe{sub 2} films from metal sulfide and selenide precursor nanocrystals by gas-phase selenization, an in-situ XRD study

    Energy Technology Data Exchange (ETDEWEB)

    Capon, B., E-mail: boris.capon@ugent.be [Department of Solid State Sciences, Ghent University, Krijgslaan 281-S1, B-9000 Ghent (Belgium); Dierick, R. [Physics and Chemistry of Nanostructures, Ghent University, Krijgslaan 281-S3, B-9000 Ghent (Belgium); Hens, Z. [Physics and Chemistry of Nanostructures, Ghent University, Krijgslaan 281-S3, B-9000 Ghent (Belgium); Center for Nano and Biophotonics, Ghent University, Ghent (Belgium); Detavernier, C. [Department of Solid State Sciences, Ghent University, Krijgslaan 281-S1, B-9000 Ghent (Belgium)

    2016-08-01

    In this work phase pure CuInSe{sub 2} thin flms were obtained by selenization of ternary CuInSe{sub 2} and CuInS{sub 2} nanocrystals and mixtures of binary nanocrystals such as CuS, In{sub 2}S{sub 3}, Cu{sub 2}Se and In{sub 2}Se{sub 3}. The temperature of the selenium source was kept at 400 °C during selenization. Monitoring the process using in-situ x-ray diffraction, the effect of selenization on the phase formation and grain growth in the precursor film was investigated. Whereas CuInSe{sub 2} and CuInS{sub 2} nanocrystals exhibit little grain growth, we found that mixtures of binary nanocrystals can show significant sintering depending on the reaction conditions. For the mixture of CuS and In{sub 2}S{sub 3} nanocrystals, the crystallinity and the morphology of the obtained fims strongly depends on the Cu/In ratio, with a Cu excess strongly promoting grain growth. With mixtures of Cu{sub 2}Se and In{sub 2}Se{sub 3} nanocrystals the selenium partial pressure plays a crucial role. Selenium evaporation from the mixed compounds results in CuInSe{sub 2} films composed of relatively small crystallites. Higher selenium partial pressures however resulted in improved sintering. Incomplete propagation of the selenization reaction through the layer was observed though, only leading to a well sintered CuInSe{sub 2} top layer above a fine grained bottom layer. - Highlights: • Different types of colloidal nanocrystals were used as precursors to obtain CuInSe{sub 2} films by gas-phase selenization. • In-situ XRD was used to study the effect of selenization on the phase formation and grain growth in the precursor films. • For a mixture of binary metal sulfides the crystallinity and the morphology strongly depend on the Cu/In ratio. • Higher selenium partial pressures result in improved sintering for a mixture of binary metal selenides.

  9. Real Time Spectroscopic Ellipsometry Analysis of First Stage CuIn1−xGaxSe2 Growth: Indium-Gallium Selenide Co-Evaporation

    Directory of Open Access Journals (Sweden)

    Puja Pradhan

    2018-01-01

    Full Text Available Real time spectroscopic ellipsometry (RTSE has been applied for in-situ monitoring of the first stage of copper indium-gallium diselenide (CIGS thin film deposition by the three-stage co-evaporation process used for fabrication of high efficiency thin film photovoltaic (PV devices. The first stage entails the growth of indium-gallium selenide (In1−xGax2Se3 (IGS on a substrate of Mo-coated soda lime glass maintained at a temperature of 400 °C. This is a critical stage of CIGS deposition because a large fraction of the final film thickness is deposited, and as a result precise compositional control is desired in order to achieve the optimum performance of the resulting CIGS solar cell. RTSE is sensitive to monolayer level film growth processes and can provide accurate measurements of bulk and surface roughness layer thicknesses. These in turn enable accurate measurements of the bulk layer optical response in the form of the complex dielectric function ε = ε1 − iε2, spectra. Here, RTSE has been used to obtain the (ε1, ε2 spectra at the measurement temperature of 400 °C for IGS thin films of different Ga contents (x deduced from different ranges of accumulated bulk layer thickness during the deposition process. Applying an analytical expression in common for each of the (ε1, ε2 spectra of these IGS films, oscillator parameters have been obtained in the best fits and these parameters in turn have been fitted with polynomials in x. From the resulting database of polynomial coefficients, the (ε1, ε2 spectra can be generated for any composition of IGS from the single parameter, x. The results have served as an RTSE fingerprint for IGS composition and have provided further structural information beyond simply thicknesses, for example information related to film density and grain size. The deduced IGS structural evolution and the (ε1, ε2 spectra have been interpreted as well in relation to observations from scanning electron microscopy, X

  10. 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.

  11. Optimization of Electrochemically Deposited Highly Doped ZnO Bilayers on Ga-Rich Chalcopyrite Selenide for Cost-Effective Photovoltaic Device Technology

    Directory of Open Access Journals (Sweden)

    Dimitra N. Papadimitriou

    2016-11-01

    Full Text Available High quality polycrystalline bilayers of aluminium doped ZnO (Al:ZnO were successively electrodeposited in the form of columnar structures preferentially oriented along the ( 10 1 ¯ 1 crystallographic direction from aqueous solution of zinc nitrate (Zn(NO32 at negative electrochemical potential of EC = (−0.8–(−1.2 V and moderate temperature of 80 °C on gallium rich (30% Ga chalcopyrite selenide Cu(In,GaSe2 (CIGS with chemically deposited ZnSe buffer (ZnSe/Cu(In,GaSe2/Mo/glass. The aluminium doped ZnO layer properties have initially been probed by deposition of Al:ZnO/i-ZnO bilayers directly on Mo/glass substrates. The band-gap energy of the Al:ZnO/i-ZnO reference layers was found to vary from 3.2 to 3.7 eV by varying the AlCl3 solute dopant concentration from 1 to 20 mM. The electrical resistivity of indium-pellet contacted highly doped Al:ZnO sheet of In/Al:ZnO/i-ZnO/Mo/glass reference samples was of the order ρ ~10−5 Ω·cm; the respective carrier concentration of the order 1022 cm−3 is commensurate with that of sputtered Al:ZnO layers. For crystal quality optimization of the bilayers by maintenance of the volatile selenium content of the chalcopyrite, they were subjected to 2-step annealing under successive temperature raise and N2 flux regulation. The hydrostatic compressive strain due to Al3+ incorporation in the ZnO lattice of bilayers processed successively with 5 and 12 mM AlCl3 dopant was εh = −0.046 and the respective stress σh = −20 GPa. The surface reflectivity of maximum 5% over the scanned region of 180–900 nm and the (optical band gap of Eg = 3.67 eV were indicative of the high optical quality of the electrochemically deposited (ECD Al:ZnO bilayers.

  12. Quijarroite, Cu6HgPb2Bi4Se12, a New Selenide from the El Dragόn Mine, Bolivia

    Directory of Open Access Journals (Sweden)

    Hans-Jürgen Förster

    2016-11-01

    Full Text Available Quijarroite, ideally Cu6HgPb2Bi4Se12, is a new selenide species from the El Dragόn mine, Department of Potosí, Bolivia. It most frequently occurs as lath-shaped thin plates (up to 150 µm in length and 20 µm in width intimately (subparallel intergrown with hansblockite, forming an angular network-like intersertal texture. Quijarroite is occasionally also present as sub- to anhedral grains up to 200 µm in length and 50 µm in width. It is non-fluorescent, black and opaque with a metallic luster and black streak. It is brittle, with an irregular fracture and no obvious cleavage and parting. In plane-polarized incident light, quijarroite is weakly pleochroic from cream to very slightly more brownish-cream, displaying no internal reflections. Between crossed polars, quijarroite is moderately anisotropic with pale orange-brown to blue rotation tints. Lamellar twinning on {110} is common; parquet twinning occurs rarely. The reflectance values in the air for the COM (Commission on Ore Mineralogy standard wavelengths (R1 and R2 are: 46.7, 46.8 (470 nm, 47.4, 48.2 (546 nm, 47.1, 48.5 (589 nm, and 46.6, 48.7 (650 nm. Electron-microprobe analyses yielded a mean composition of Cu 13.34, Ag 1.02, Hg 7.67, Pb 16.87, Co 0.03, Ni 0.15, Bi 27.65, Se 33.52, total 100.24 wt %. The mean empirical formula, normalized to 25 apfu (atoms per formula unit, is (Cu5.84Ag0.26Σ = 6.10(Hg1.06Ni0.07Co0.01Σ = 1.14Pb2.27Bi3.68Se11.81 (n = 24. The simplified formula is Cu6HgPb2Bi4Se12. Quijarroite is orthorhombic, space group Pmn21, with a = 9.2413(8, b = 9.0206(7, c = 9.6219(8 Å, V = 802.1(1 Å3, Z = 1. The calculated density is 5.771 g·cm−3. The five strongest X-ray powder-diffraction lines (d in Å (I/I0 (hkl are: 5.36 (55 (111, 3.785 (60 (211, 3.291 (90 (022, 3.125 (100 (212, and 2.312 (50 (400. The crystal structure of quijarroite can be considered a galena derivative and could be derived from that of bournonite. It is a primary mineral, deposited from an

  13. The role of dysprosium on the structural and magnetic properties of (Nd{sub 1−x}Dy{sub x}){sub 2}Fe{sub 14}B nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Rahimi, Hamed; Ghasemi, Ali, E-mail: ali13912001@yahoo.com; Mozaffarinia, Reza; Tavoosi, Majid

    2017-02-15

    In current work, Nd2Fe14B nanoparticles was synthesized by sol-gel method. Dysprosium powders were added into Nd2Fe14B nanoparticles by mechanical alloying process in order to enhancement of coercivity. The phase analysis, structure, and magnetic properties of annealed (Nd{sub 1−x}Dy{sub x}){sub 2}Fe{sub 14}B nanoparticles with different Dy-content (x=0.1, 0.2, 0.3, 0.4, 0.5, 0.6) were investigated by employing X-ray diffraction, X-ray photoelectron spectroscopy, energy dispersive spectroscopy, field emission scanning electron microscope, transmission electron microscope and vibrating sample magnetometer techniques. The results showed that with an increase in Dy amounts, the coercivity of particles increased from 2.9 kOe to 13.4 kOe and then decreased to 5.6 kOe. By adding an optimum amount of Dy (x=0.4), the coercivity was significantly increased from 2.9 kOe to 13.4 kOe. The average particle size of annealed (Nd{sub 1−x}Dy{sub x}){sub 2}Fe{sub 14}B nanoparticles was below 10 nm. Magnetization reversal studies indicate that the coercivity of milled and annealed (Nd{sub 1−x}Dy{sub x}){sub 2}Fe{sub 14}B nanoparticles is controlled by the nucleation of reversed magnetic domains. The experimental results in the angular dependence of coercivity for (Nd{sub 1−x}Dy{sub x}){sub 2}Fe{sub 14}B permanent magnets showed that the normalized coercivity of the permanent magnets H{sub c}(θ)/H{sub c}(0) increases from 1 to about 1.2–1.5 with increasing θ from 0 to about π/3, for x=0.4–0.6. - Highlights: • Dy was added to Nd{sub 2}Fe{sub 14}B nanoparticles to improve the coercivity. • A maximum squareness ratio of 0.99 was obtained. • The average particle size decreased with an increase in Dy-content.

  14. The decay of hot dysprosium nuclei

    International Nuclear Information System (INIS)

    Atac, A.; Rekstad, J.; Guttormsen, M.; Messelt, S.; Ramsoey, T.; Thorsteinsen, T.F.; Loevhoeiden, G.; Roedland, T.

    1987-03-01

    The γ-decay following the 162,163 Dy( 3 He,αxn) reactions with E 3 He =45 MeV has been studied. Non-statistical γ-radiation with energies of E γ ≅1 MeV and ≅2 MeV is found for various residual nuclei. The properties of these γ-ray bumps depend on the number of emitted neutrons and reveal an odd-even mass dependence. New techniques to extract average neutron energies as a function of excitation energy and of the number of emitted neutrons are employed. The deduced neutron energies are consistent with Fermi-gas model predictions

  15. Synthesis and magnetic structure of the layered manganese oxide selenide Sr{sub 2}MnO{sub 2}Ag{sub 1.5}Se{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Blandy, Jack N. [Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR (United Kingdom); Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE (United Kingdom); Boskovic, Jelena C. [Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR (United Kingdom); Clarke, Simon J., E-mail: simon.clarke@chem.ox.ac.uk [Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR (United Kingdom)

    2017-01-15

    The synthesis of a high-purity sample of the layered oxide selenide Sr{sub 2}MnO{sub 2}Ag{sub 1.5}Se{sub 2} is reported. At ambient temperature it crystallises in the space group I4/mmm with two formula units in the unit cell and lattice parameters a=4.08771(1) Å, c=19.13087(8) Å. The compound displays mixed-valent manganese in a formal oxidation state close to +2.5 and powder neutron diffraction measurements reveal that below the Néel temperature of 63(1) K this results in an antiferromagnetic structure which may be described as A-type, modelled in the magnetic space group P{sub I}4/mnc (128.410 in the Belov, Neronova and Smirnova (BNS) scheme) in which localised Mn moments of 3.99(2) μ{sub B} are arranged in ferromagnetic layers which are coupled antiferromagnetically. In contrast to the isostructural compound Sr{sub 2}MnO{sub 2}Cu{sub 1.5}S{sub 2}, Sr{sub 2}MnO{sub 2}Ag{sub 1.5}Se{sub 2} does not display long range ordering of coinage metal ions and vacancies, nor may significant amounts of the coinage metal readily be deintercalated using soft chemical methods. - Graphical abstract: Sr{sub 2}MnO{sub 2}Ag{sub 1.5}Se{sub 2} containing mixed valent Mn ions undergoes magnetic ordering with ferromagnetic coupling within MnO{sub 2} sheets and antiferromagnetic coupling between MnO{sub 2} sheets. - Highlights: • High purity sample of Sr{sub 2}MnO{sub 2}Ag{sub 1.5}Se{sub 2} obtained. • Magnetic structure determined. • Compared with related mixed-valent manganite oxide chalcogenides.

  16. Improving the efficiency of copper indium gallium (Di-)selenide (CIGS) solar cells through integration of a moth-eye textured resist with a refractive index similar to aluminum doped zinc oxide

    Energy Technology Data Exchange (ETDEWEB)

    Burghoorn, M.; Kniknie, B.; Deelen, J. van; Ee, R. van [The Netherlands Organisation for Applied Scientific Research (TNO), De Rondom 1, 5612 AP, Eindhoven (Netherlands); Xu, M. [The Netherlands Organisation for Applied Scientific Research (TNO), De Rondom 1, 5612 AP, Eindhoven (Netherlands); Delft University of Technology, Optics Group, Van der Waalsweg 8, 2628 CH, Delft (Netherlands); Vroon, Z. [The Netherlands Organisation for Applied Scientific Research (TNO), De Rondom 1, 5612 AP, Eindhoven (Netherlands); Zuyd Hogeschool, Nieuw Eyckholt 300, 6419 DJ, Heerlen (Netherlands); Belt, R. van de [Kriya Materials BV, Urmonderbaan 22, 6167 RD, Geleen (Netherlands); Buskens, P., E-mail: pascal.buskens@tno.nl, E-mail: buskens@dwi.rwth-aachen.de [The Netherlands Organisation for Applied Scientific Research (TNO), De Rondom 1, 5612 AP, Eindhoven (Netherlands); DWI – Leibniz Institute for Interactive Materials, Forckenbeckstrasse 50, 52056, Aachen (Germany)

    2014-12-15

    Textured transparent conductors are widely used in thin-film silicon solar cells. They lower the reflectivity at interfaces between different layers in the cell and/or cause an increase in the path length of photons in the Si absorber layer, which both result in an increase in the number of absorbed photons and, consequently, an increase in short-circuit current density (J{sub sc}) and cell efficiency. Through optical simulations, we recently obtained strong indications that texturing of the transparent conductor in copper indium gallium (di-)selenide (CIGS) solar cells is also optically advantageous. Here, we experimentally demonstrate that the J{sub sc} and efficiency of CIGS solar cells with an absorber layer thickness (d{sub CIGS}) of 0.85 μm, 1.00 μm and 2.00 μm increase through application of a moth-eye textured resist with a refractive index that is sufficiently similar to AZO (n{sub resist} = 1.792 vs. n{sub AZO} = 1.913 at 633 nm) to avoid large optical losses at the resist-AZO interface. On average, J{sub sc} increases by 7.2%, which matches the average reduction in reflection of 7.0%. The average relative increase in efficiency is slightly lower (6.0%). No trend towards a larger relative increase in J{sub sc} with decreasing d{sub CIGS} was observed. Ergo, the increase in J{sub sc} can be fully explained by the reduction in reflection, and we did not observe any increase in J{sub sc} based on an increased photon path length.

  17. Improving the efficiency of copper indium gallium (Di-selenide (CIGS solar cells through integration of a moth-eye textured resist with a refractive index similar to aluminum doped zinc oxide

    Directory of Open Access Journals (Sweden)

    M. Burghoorn

    2014-12-01

    Full Text Available Textured transparent conductors are widely used in thin-film silicon solar cells. They lower the reflectivity at interfaces between different layers in the cell and/or cause an increase in the path length of photons in the Si absorber layer, which both result in an increase in the number of absorbed photons and, consequently, an increase in short-circuit current density (Jsc and cell efficiency. Through optical simulations, we recently obtained strong indications that texturing of the transparent conductor in copper indium gallium (di-selenide (CIGS solar cells is also optically advantageous. Here, we experimentally demonstrate that the Jsc and efficiency of CIGS solar cells with an absorber layer thickness (dCIGS of 0.85 μm, 1.00 μm and 2.00 μm increase through application of a moth-eye textured resist with a refractive index that is sufficiently similar to AZO (nresist = 1.792 vs. nAZO = 1.913 at 633 nm to avoid large optical losses at the resist-AZO interface. On average, Jsc increases by 7.2%, which matches the average reduction in reflection of 7.0%. The average relative increase in efficiency is slightly lower (6.0%. No trend towards a larger relative increase in Jsc with decreasing dCIGS was observed. Ergo, the increase in Jsc can be fully explained by the reduction in reflection, and we did not observe any increase in Jsc based on an increased photon path length.

  18. Full four-component relativistic calculations of the one-bond 77Se-13C spin-spin coupling constants in the series of selenium heterocycles and their parent open-chain selenides.

    Science.gov (United States)

    Rusakov, Yury Yu; Rusakova, Irina L; Krivdin, Leonid B

    2014-05-01

    Four-component relativistic calculations of (77)Se-(13)C spin-spin coupling constants have been performed in the series of selenium heterocycles and their parent open-chain selenides. It has been found that relativistic effects play an essential role in the selenium-carbon coupling mechanism and could result in a contribution of as much as 15-25% of the total values of the one-bond selenium-carbon spin-spin coupling constants. In the overall contribution of the relativistic effects to the total values of (1)J(Se,C), the scalar relativistic corrections (negative in sign) by far dominate over the spin-orbit ones (positive in sign), the latter being of less than 5%, as compared to the former (ca 20%). A combination of nonrelativistic second-order polarization propagator approach (CC2) with the four-component relativistic density functional theory scheme is recommended as a versatile tool for the calculation of (1)J(Se,C). Solvent effects in the values of (1)J(Se,C) calculated within the polarizable continuum model for the solvents with different dielectric constants (ε 2.2-78.4) are next to negligible decreasing negative (1)J(Se,C) in absolute value by only about 1 Hz. The use of the locally dense basis set approach applied herewith for the calculation of (77)Se-(13)C spin-spin coupling constants is fully justified resulting in a dramatic decrease in computational cost with only 0.1-0.2-Hz loss of accuracy. Copyright © 2014 John Wiley & Sons, Ltd.

  19. Structural, magnetic, and electronic properties of iron selenide Fe{sub 6-7}Se{sub 8} nanoparticles obtained by thermal decomposition in high-temperature organic solvents

    Energy Technology Data Exchange (ETDEWEB)

    Lyubutin, I. S., E-mail: lyubutinig@mail.ru, E-mail: crlin@mail.npue.edu.tw; Funtov, K. O.; Dmitrieva, T. V.; Starchikov, S. S. [Shubnikov Institute of Crystallography, Russian Academy of Sciences, Moscow 119333 (Russian Federation); Lin, Chun-Rong, E-mail: lyubutinig@mail.ru, E-mail: crlin@mail.npue.edu.tw [Department of Applied Physics, National Pingtung University of Education, Pingtung 90003, Taiwan (China); Siao, Yu-Jhan [Department of Mechanical Engineering, Southern Taiwan University of Science and Technology, Tainan 71005, Taiwan (China); Chen, Mei-Li [Department of Electro-optical Engineering, Southern Taiwan University of Science and Technology, Tainan 71005, Taiwan (China)

    2014-07-28

    Iron selenide nanoparticles with the NiAs-like crystal structure were synthesized by thermal decomposition of iron chloride and selenium powder in a high-temperature organic solvent. Depending on the time of the compound processing at 340 °C, the nanocrystals with monoclinic (M)-Fe{sub 3}Se{sub 4} or hexagonal (H)-Fe{sub 7}Se{sub 8} structures as well as a mixture of these two phases can be obtained. The magnetic behavior of the monoclinic and hexagonal phases is very different. The applied-field and temperature dependences of magnetization reveal a complicated transformation between ferrimagnetic (FRM) and antiferromagnetic (AFM) structures, which can be related to the spin rotation process connected with the redistribution of cation vacancies. From XRD and Mössbauer data, the 3c type superstructure of vacancy ordering was found in the hexagonal Fe{sub 7}Se{sub 8}. Redistribution of vacancies in Fe{sub 7}Se{sub 8} from random to ordered leads to the transformation of the magnetic structure from FRM to AFM. The Mössbauer data indicate that vacancies in the monoclinic Fe{sub 3}Se{sub 4} prefer to appear near the Fe{sup 3+} ions and stimulate the magnetic transition with the rotation of the Fe{sup 3+} magnetic moments. Unusually high coercive force H{sub c} was found in both (H) and (M) nanocrystals with the highest (“giant”) value of about 25 kOe in monoclinic Fe{sub 3}Se{sub 4}. This is explained by the strong surface magnetic anisotropy which is essentially larger than the core anisotropy. Such a large coercivity is rare for materials without rare earth or noble metal elements, and the Fe{sub 3}Se{sub 4}-based compounds can be the low-cost, nontoxic alternative materials for advanced magnets. In addition, an unusual effect of “switching” of magnetization in a field of 10 kOe was found in the Fe{sub 3}Se{sub 4} nanoparticles below 280 K, which can be important for applications.

  20. Effect of increasing tellurium content on the electronic and optical properties of cadmium selenide telluride alloys CdSe{sub 1-x}Te{sub x}: An ab initio study

    Energy Technology Data Exchange (ETDEWEB)

    Reshak, Ali Hussain, E-mail: maalidph@yahoo.co.uk [Institute of Physical Biology-South Bohemia University, Nove Hrady 37333 (Czech Republic); School of Material Engineering, Malaysia University of Perlis, P.O Box 77, d/a Pejabat Pos Besar, 01007 Kangar, Perlis (Malaysia); Kityk, I.V. [Electrical Engineering Department, Technical University of Czestochowa, Al. Armii Krajowej 17/19, Czestochowa (Poland); Khenata, R. [Laboratoire de Physique Quantique et de Modelisation Mathematique de la Matiere (LPQ3 M), universite de Mascara, Mascara 29000 (Algeria); Department of Physics and Astronomy, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Auluck, S. [National Physical Laboratory Dr. K S Krishnan Marg, New Delhi 110012 (India)

    2011-06-16

    Highlights: > Theoretical study of effect of vary Te content on band structure, density of states, linear and nonlinear optical susceptibilities of CdSe{sub 1-x}Te{sub x}. > Increasing Te content leads to a decrease in the energy band gap. > Significant enhancement of the electronic properties as a function of tellurium concentration - Abstract: An all electron full potential linearized augmented plane wave method, within a framework of GGA (EV-GGA) approach, has been used for an ab initio theoretical study of the effect of increasing tellurium content on the band structure, density of states, and the spectral features of the linear and nonlinear optical susceptibilities of the cadmium-selenide-telluride ternary alloys CdSe{sub 1-x}Te{sub x} (x = 0.0, 0.25, 0.5, 0.75 and 1.0). Our calculations show that increasing Te content leads to a decrease in the energy band gap. We find that the band gaps are 0.95 (1.76), 0.89 (1.65), 0.83 (1.56), 0.79 (1.44) and 0.76 (1.31) eV for x = 0.0, 0.25, 0.5, 0.75 and 1.0 in the cubic structure. As these alloys are known to have a wurtzite structure for x less than 0.25, the energy gaps are 0.8 (1.6) eV and 0.7 (1.55) eV for the wurtzite structure (x = 0.0, 0.25) for the GGA (EV-GGA) exchange correlation potentials. This reduction in the energy gaps enhances the functionality of the CdSe{sub 1-x}Te{sub x} alloys, at least for these concentrations, leading to an increase in the effective second-order susceptibility coefficients from 16.75 pm/V (CdSe) to 18.85 pm/V (CdSe{sub 0.75}Te{sub 0.25}), 27.23 pm/V (CdSe{sub 0.5}Te{sub 0.5}), 32.25 pm/V (CdSe{sub 0.25}Te{sub 0.75}), and 37.70 pm/V (CdTe) for the cubic structure and from 12.65 pm/V (CdSe) to 21.11 pm/V (CdSe{sub 0.75}Te{sub 0.25}) in the wurtzite structure. We find a nonlinear relationship between the absorption/emission energies and composition, and a significant enhancement of the electronic properties as a function of tellurium concentration. This variation will help in

  1. Positron lifetime experiments in indium selenide

    International Nuclear Information System (INIS)

    Cruz, R.M. de la; Pareja, R.

    1988-01-01

    Positron lifetime experiments have been performed on as-grown samples which had been isochronally annealed up to 820 K and plastically deformed and these experiments yield a constant lifetime of 282 ± 2 ps which is attributed to bulk positron states in InSe. Electron-irradiated samples exhibit a two-component spectrum, revealing the presence of positron traps which anneal out at about 330 K. The nature of the native shallow donors in InSe is discussed in the light of the results, which support the idea that native donor centres are probably interstitial In atoms rather than Se vacancies. Positron trapping observed in the electron-irradiated samples is attributed to defects related to In vacancies. (author)

  2. Lead selenide quantum dot polymer nanocomposites

    Science.gov (United States)

    Waldron, Dennis L.; Preske, Amanda; Zawodny, Joseph M.; Krauss, Todd D.; Gupta, Mool C.

    2015-02-01

    Optical absorption and fluorescence properties of PbSe quantum dots (QDs) in an Angstrom Bond AB9093 epoxy polymer matrix to form a nanocomposite were investigated. To the authors’ knowledge, this is the first reported use of AB9093 as a QD matrix material and it was shown to out-perform the more common poly(methyl methacrylate) matrix in terms of preserving the optical properties of the QD, resulting in the first reported quantum yield (QY) for PbSe QDs in a polymer matrix, 26%. The 1-s first excitonic absorption peak of the QDs in a polymer matrix red shifted 65 nm in wavelength compared to QDs in a hexane solution, while the emission peak in the polymer matrix red shifted by 38 nm. The fluorescence QY dropped from 55% in hexane to 26% in the polymer matrix. A time resolved fluorescence study of the QDs showed single exponential lifetimes of 2.34 and 1.34 μs in toluene solution and the polymer matrix respectively.

  3. Mercury Cadmium Selenide for Infrared Detection

    Science.gov (United States)

    2013-06-01

    were grown using elemental mercury (Hg), cadmium (Cd), and selenium (Se) sources. The beam equiva- lent pressure ( BEP ) emanating from all sources was...flux), the BEP measured for the cracker source was found to vary with the cracking zone temperature, tracking with the data found in Ref. 7. This sug...The Se BEP measured for the typical cracking zone temperature of 800 C was found to be close to a factor of two lower than at the typical effusion cell

  4. Synthesis and characterization of phosphors based on calcium and magnesium silicates doped with europium and dysprosium; Síntese e caracterização de fósforos a base de silicatos de cálcio e magnésio dopados com európio e disprósio

    Energy Technology Data Exchange (ETDEWEB)

    Misso, Agatha Matos

    2016-07-01

    Ca and Mg silicates based phosphors were prepared by sol-gel method combined with the molten salts process. The gel of silica was obtained from Na{sub 2}SiO{sub 3} solution by using europium, dysprosium, calcium and magnesium chloride solutions. Therefore, those chlorides were homogeneously dispersed into the gel. The obtained gel was dried and heat treated to 900° C for 1h to allow the fusion of the present salts. Then it was water washed until negative test for Cl{sup -}, and dried. The reduction of the europium to Eu{sup 2+} was performed under atmosphere of 5% of H{sub 2} and 95% of Ar to 900° C for 3h, to reach CaMgSi{sub 2}O{sub 6}:Eu{sup 2+} and CaMgSi{sub 2}O{sub 6}:Eu{sup 2+}:Dy{sup 3+} phosphors. Diopside was identified as main crystalline phase and quartz, as secondary phase from XRD (X-ray diffraction) patterns. SEM (scanning electron microscopy) micrographs, of the samples showed needles, spheres, leaves and rods of particles and agglomerates. Thermal analysis (TGA-DTGA) curves revealed that the crystallization temperature of CaMgSi{sub 2}O{sub 6}:Eu{sup 2+} lies around 765° C. Photoluminescence spectroscopy of the phosphors was studied based on interconfigurational 4f{sup N} → 4f{sup N-1} 5d transition of Eu{sup 2+} ion. The spectra of excitation showed 4f{sup N} → 4f{sup N-1} 5d transition of Eu{sup 2+} ion broad band, related to the ligand to metal charge transfer transition (LMCT) O{sup 2-} (2p) → Eu{sup 3+} in the 250 nm region, when the emission is monitored at 583,5 nm. It also presents the 4f ↔ 4f transitions of Eu{sup 3+} ion bands, showing the {sup 7}F{sub 0} → {sup 5}L{sub 6} transition at 393 nm. From emission spectra with excitation monitored at 393 nm, it can be observed fine peaks between 570 and 750 nm which are characteristics of {sup 5}D{sub 0} → {sup 7}F{sub J} (J = 0 - 5) transition of Eu{sup 3+} ion, indicating that the Eu{sup 3+} ion occupies a site with center of inversion. Finally, the obtained results indicate

  5. Photodissociation spectroscopy of the dysprosium monochloride molecular ion

    Energy Technology Data Exchange (ETDEWEB)

    Dunning, Alexander, E-mail: alexander.dunning@gmail.com; Schowalter, Steven J.; Puri, Prateek; Hudson, Eric R. [Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States); Petrov, Alexander; Kotochigova, Svetlana [Department of Physics, Temple University, Philadelphia, Pennsylvania 19122 (United States)

    2015-09-28

    We have performed a combined experimental and theoretical study of the photodissociation cross section of the molecular ion DyCl{sup +}. The photodissociation cross section for the photon energy range 35 500 cm{sup −1} to 47 500 cm{sup −1} is measured using an integrated ion trap and time-of-flight mass spectrometer; we observe a broad, asymmetric profile that is peaked near 43 000 cm{sup −1}. The theoretical cross section is determined from electronic potentials and transition dipole moments calculated using the relativistic configuration-interaction valence-bond and coupled-cluster methods. The electronic structure of DyCl{sup +} is extremely complex due to the presence of multiple open electronic shells, including the 4f{sup 10} configuration. The molecule has nine attractive potentials with ionically bonded electrons and 99 repulsive potentials dissociating to a ground state Dy{sup +} ion and Cl atom. We explain the lack of symmetry in the cross section as due to multiple contributions from one-electron-dominated transitions between the vibrational ground state and several resolved repulsive excited states.

  6. Influence of dysprosium addition on the structural, morphological ...

    Indian Academy of Sciences (India)

    Microwave absorption properties of hexaferrite (70 wt%)–acrylic resin. (30 wt%) composites ... the RE ions were substituted for Sr (Ba) or Fe, taking into accounts the .... general the RE substitutions weaken the super exchange interactions ...

  7. Single molecule magnet behaviour in robust dysprosium-biradical complexes.

    Science.gov (United States)

    Bernot, Kevin; Pointillart, Fabrice; Rosa, Patrick; Etienne, Mael; Sessoli, Roberta; Gatteschi, Dante

    2010-09-21

    A Dy-biradical complex was synthesized and characterized down to very low temperature. ac magnetic measurements reveal single molecule magnet behaviour visible without any application of dc field. The transition to the quantum tunneling regime is evidenced. Photophysical and EPR measurements provide evidence of the excellent stability of these complexes in solution.

  8. Scissors Mode of Dipolar Quantum Droplets of Dysprosium Atoms

    Science.gov (United States)

    Ferrier-Barbut, Igor; Wenzel, Matthias; Böttcher, Fabian; Langen, Tim; Isoard, Mathieu; Stringari, Sandro; Pfau, Tilman

    2018-04-01

    We report on the observation of the scissors mode of a single dipolar quantum droplet. The existence of this mode is due to the breaking of the rotational symmetry by the dipole-dipole interaction, which is fixed along an external homogeneous magnetic field. By modulating the orientation of this magnetic field, we introduce a new spectroscopic technique for studying dipolar quantum droplets. This provides a precise probe for interactions in the system, allowing us to extract a background scattering length for 164Dy of 69 (4 )a0 . Our results establish an analogy between quantum droplets and atomic nuclei, where the existence of the scissors mode is also only due to internal interactions. They further open the possibility to explore physics beyond the available theoretical models for strongly dipolar quantum gases.

  9. Calorimetric investigation of an yttrium-dysprosium spin glass

    International Nuclear Information System (INIS)

    Wenger, L.E.

    1978-01-01

    In an effort to compare the spin glass characteristics of yttrium--rare earth alloys with those of the noble-metal spin glasses, the susceptibility and heat capacity of Y/sub 0.98/Dy/sub 0.02/ have been measured in the temperature range 2.5--40 K. The low-field ac susceptibility measurement shows the characteristic cusp-like peak at 7.64 K. The magnetic specific heat of the same sample shows a peak at 7.0 K and may be qualitatively described as a semi-cusp. The magnetic entropy change from absolute zero to 7 K is approximately 0.52 of cR ln(2J+1). These results are qualitatively different than previous calorimetric results on the archetypal spin glasses, AuFe and CuMn, where rounded maxima are observed at temperatures above the spin glass transition temperatures

  10. Emission spectra of yttrium vanadate doped with bismuth and dysprosium

    International Nuclear Information System (INIS)

    Pawar, B.V.; Patil, R.N.

    1975-01-01

    The fluorescence spectra of YVO 4 :Bi and YVO 4 :Bi:Dy phosphors under X-rays and ultra-violet radiation have been studied. The observations on the phosphors with constant Bi 3+ and varying Dy 3+ concentration can be attributed to radiationless transfer of energy from Bi 3+ to Dy 3+ coupled with non-radiative losses due to self-quenching at higher level of Dy 3+ concentration. While the observations on the phosphors with constant Dy 3+ and varying Bi 3+ concentration indicate that there is radiationless transfer from Bi 3+ to Dy 3+ under X-ray or UV irradiation. (author)

  11. Dysprosium-free melt-spun permanent magnets

    International Nuclear Information System (INIS)

    Brown, D N; Wu, Z; He, F; Miller, D J; Herchenroeder, J W

    2014-01-01

    Melt-spun NdFeB powders can be formed into a number of different types of permanent magnet for a variety of applications in electronics, automotive and clean technology industries. The melt-spinning process produces flake powder with a fine uniform array of nanoscale Nd 2 Fe 14 B grains. These powders can be net-shape formed into isotropic polymer-bonded magnets or hot formed into fully dense magnets. This paper discusses the influence of heavy rare earth elements and microstructure on the magnetic performance, thermal stability and material cost of NdFeB magnets. Evidence indicates that melt-spun nanocrystalline NdFeB magnets are less dependent on heavy rare earth elements for high-temperature performance than the alternative coarser-grained sintered NdFeB magnets. In particular, hot-pressed melt-spun magnets are an attractive low-cost solution for applications that require thermal stability up to 175–200 °C. (paper)

  12. Dysprosium-free melt-spun permanent magnets.

    Science.gov (United States)

    Brown, D N; Wu, Z; He, F; Miller, D J; Herchenroeder, J W

    2014-02-12

    Melt-spun NdFeB powders can be formed into a number of different types of permanent magnet for a variety of applications in electronics, automotive and clean technology industries. The melt-spinning process produces flake powder with a fine uniform array of nanoscale Nd2Fe14B grains. These powders can be net-shape formed into isotropic polymer-bonded magnets or hot formed into fully dense magnets. This paper discusses the influence of heavy rare earth elements and microstructure on the magnetic performance, thermal stability and material cost of NdFeB magnets. Evidence indicates that melt-spun nanocrystalline NdFeB magnets are less dependent on heavy rare earth elements for high-temperature performance than the alternative coarser-grained sintered NdFeB magnets. In particular, hot-pressed melt-spun magnets are an attractive low-cost solution for applications that require thermal stability up to 175-200 °C.

  13. Crystal and molecular structure of dysprosium (3) n-aminobenzoate

    International Nuclear Information System (INIS)

    Khiyalov, M.S.; Amiraslanov, I.R.; Mamedov, Kh.S.; Movsumov, Eh.M.

    1981-01-01

    The X ray diffraction investigation of the Dy(NH 2 C 6 H 4 COO) 3 x3H 2 O complex is carried out. Triclinic crystals have lattice parameters α=11.095(15), b=9.099(17), c=12.780 (15)A, α=108.051(12), β=89.072(10); γ=104.954(12) 0 , space group P anti 1, Z=2. The structure consists of dimer molecules. The third water molecule in the formula is an outer spherical one. The average lengths of Dy-O and Dy-OH 2 are 2.39 and 2.40 A respectively, the average value of Dy-O in bridge carboxylates (2.26A) is remarkably shorter. Hydrogen bonds between amine ligand ends, carboxylic groups oxygen and water molecules bind complex molecules into the three-dimensional frame [ru

  14. Microscopic study of neutron-rich dysprosium isotopes

    International Nuclear Information System (INIS)

    Vargas, Carlos E.; Velazquez, Victor; Lerma, Sergio

    2013-01-01

    Microscopic studies in heavy nuclei are very scarce due to large valence spaces involved. This computational problem can be avoided by means of the use of symmetry-based models. Ground-state, γ and β bands, and their B(E2) transition strengths in 160-168 Dy isotopes, are studied in the framework of the pseudo-SU(3) model which includes the preserving symmetry Q . Q term and the symmetry-breaking Nilsson and pairing terms, systematically parametrized. Additionally, three rotor-like terms are considered, whose free parameters, fixed for all members of the chain, are used to fine tune the moment of inertia of rotational bands and the band head of γ and β bands. The model succesfully describes in a systematic way rotational features in these nuclei and allows to extrapolate toward the midshell nucleus 170 Dy. The results presented show that it is possible to study a full chain of isotopes or isotones in the region with the present model. (orig.)

  15. Microscopic study of neutron-rich dysprosium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, Carlos E. [Universidad Veracruzana, Facultad de Fisica e Inteligencia Artificial, Xalapa (Mexico); Universidad Nacional Autonoma de Mexico, Facultad de Ciencias, Apartado Postal 70-542, Mexico D.F. (Mexico); Velazquez, Victor [Universidad Nacional Autonoma de Mexico, Facultad de Ciencias, Apartado Postal 70-542, Mexico D.F. (Mexico); Lerma, Sergio [Universidad Veracruzana, Facultad de Fisica e Inteligencia Artificial, Xalapa (Mexico)

    2013-01-15

    Microscopic studies in heavy nuclei are very scarce due to large valence spaces involved. This computational problem can be avoided by means of the use of symmetry-based models. Ground-state, {gamma} and {beta} bands, and their B(E2) transition strengths in {sup 160-168}Dy isotopes, are studied in the framework of the pseudo-SU(3) model which includes the preserving symmetry Q . Q term and the symmetry-breaking Nilsson and pairing terms, systematically parametrized. Additionally, three rotor-like terms are considered, whose free parameters, fixed for all members of the chain, are used to fine tune the moment of inertia of rotational bands and the band head of {gamma} and {beta} bands. The model succesfully describes in a systematic way rotational features in these nuclei and allows to extrapolate toward the midshell nucleus {sup 170}Dy. The results presented show that it is possible to study a full chain of isotopes or isotones in the region with the present model. (orig.)

  16. Structural and magnetic study of dysprosium substituted cobalt ferrite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Hemaunt, E-mail: hvatsal@gmail.com [Department of Physics, Govind Ballabh Pant University of Agr. & Technology, Pantnagar, Uttarakhand 263145 (India); Srivastava, R.C. [Department of Physics, Govind Ballabh Pant University of Agr. & Technology, Pantnagar, Uttarakhand 263145 (India); Pal Singh, Jitendra [Advanced Analysis Centre, Korea Institute of Science and Technology, Seoul 02792 (Korea, Republic of); Negi, P. [Department of Physics, Govind Ballabh Pant University of Agr. & Technology, Pantnagar, Uttarakhand 263145 (India); Agrawal, H.M. [Advanced Analysis Centre, Korea Institute of Science and Technology, Seoul 02792 (Korea, Republic of); Das, D. [UGC-DAE CSR Kolkata Centre, Kolkata 700098 (India); Hwa Chae, Keun [Advanced Analysis Centre, Korea Institute of Science and Technology, Seoul 02792 (Korea, Republic of)

    2016-03-01

    The present work investigates the magnetic behavior of Dy{sup 3+} substituted cobalt ferrite nanoparticles. X-ray diffraction studies reveal presence of cubic spinel phases in these nanoparticles. Raman spectra of these nanoparticles show change in intensity of Raman bands, which reflects cation redistribution in cubic spinel lattice. Saturation magnetization and coercivity decrease with increase of Dy{sup 3+}concentration in these nanoparticles. Room temperature Mössbauer measurements show the cation redistribution in these nanoparticles and corroborates the results obtained from Raman Spectroscopic measurements. Decrease in magnetization of Dy{sup 3+} substituted cobalt ferrite is attributed to the reduction in the magnetic interaction and cation redistribution. - Highlights: • Slight decrease in crystallite size after Dy{sup 3+} doping. • Saturation magnetization and coercivity decrease after Dy{sup 3+} doping. • Mössbauer measurements show the cation redistribution in the samples.

  17. Dysprosium Acetylacetonato Single-Molecule Magnet Encapsulated in Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Ryo Nakanishi

    2016-12-01

    Full Text Available Dy single-molecule magnets (SMMs, which have several potential uses in a variety of applications, such as quantum computing, were encapsulated in multi-walled carbon nanotubes (MWCNTs by using a capillary method. Encapsulation was confirmed by using transmission electron microscopy (TEM. In alternating current magnetic measurements, the magnetic susceptibilities of the Dy acetylacetonato complexes showed clear frequency dependence even inside the MWCNTs, meaning that this hybrid can be used as magnetic materials in devices.

  18. On the specific electrophysical properties of n-InSe single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Abdinov, A. Sh., E-mail: abdinov-axmed@yahoo.com [Baku State University (Azerbaijan); Babaeva, R. F., E-mail: babaeva-rena@yandex.ru; Rzaev, R. M., E-mail: abdinov-axmed@yandex.ru [Azerbaijan State Economic University (Azerbaijan); Ragimova, N. A.; Amirova, S. I. [Baku State University (Azerbaijan)

    2016-01-15

    The temperature dependences of physical parameters (the conductivity and the Hall constant) are experimentally investigated for pure indium-selenide (n-InSe) crystals and those lightly doped with rareearth elements (gadolinium, holmium, and dysprosium). It is established that the obtained results depend on the origin of the samples under investigation and prove to be contradictory for different samples. The obtained experimental results are treated taking into account the presence of chaotic large-scale defects and drift barriers caused by them in these samples.

  19. Two hexagonal series of lanthanoid(III) oxide fluoride selenides.: M{sub 6}O{sub 2}F{sub 8}Se{sub 3} (M = La - Nd) and M{sub 2}OF{sub 2}Se (M = Nd, Sm, Gd - Ho)

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, Dirk D.; Grossholz, Hagen; Wolf, Sarah; Schleid, Thomas [Institut fuer Anorganische Chemie, Universitaet Stuttgart (Germany); Janka, Oliver [Institut fuer Anorganische Chemie, Universitaet Stuttgart (Germany); Institut fuer Anorganische und Analytische Chemie, Westfaelische Wilhelms-Universitaet Muenster (Germany); Mueller, Alexander C. [Institut fuer Anorganische Chemie, Universitaet Stuttgart (Germany); Institut fuer Textilchemie und Chemiefasern, Denkendorf (Germany)

    2015-09-15

    Two hexagonal series of lanthanoid(III) oxide fluoride selenides with similar structure types can be obtained by the reaction of the components MF{sub 3}, M{sub 2}O{sub 3}, M, and Se in sealed niobium tubes at 850 C using CsI as fluxing agent. The compounds with the lighter and larger representatives (M = La - Nd) occur with the formula M{sub 6}O{sub 2}F{sub 8}Se{sub 3}, whereas with the heavier and smaller ones (M = Nd, Sm, Gd - Ho) their composition is M{sub 2}OF{sub 2}Se. For both systems single-crystal determinations were used in all cases. The compounds crystallize in the hexagonal crystal system (space group: P6{sub 3}/m) with lattice parameters of a = 1394-1331 pm and c = 403-372 pm (Z = 2 for M{sub 6}O{sub 2}F{sub 8}Se{sub 3} and Z = 6 for M{sub 2}OF{sub 2}Se). The (M1){sup 3+} cations show different square antiprismatic coordination spheres with or without an extra capping fluoride anion. All (M2){sup 3+} cations exhibit a ninefold coordination environment shaped as tricapped trigonal prism. In both structure types the Se{sup 2-} anions are sixfold coordinated as trigonal prisms of M{sup 3+} cations, being first condensed by edges to generate trimeric units and then via faces to form strands running along [001]. The light anions reside either in threefold triangular or in fourfold tetrahedral cationic coordination. For charge compensation, both structures have to contain a certain amount of oxide besides fluoride anions. Since F{sup -} and O{sup 2-} can not be distinguished by X-ray diffraction, bond-valence calculations were used to address the problem of their adjunction to the available crystallographic sites. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Two-dimensional cadmium selenide electronic and optical properties

    Indian Academy of Sciences (India)

    2017-09-12

    Sep 12, 2017 ... determine the energy gap within the plasmon pole and the random phase ... the stability and possible applications in the fabrication of thin ... conditions and characterization [19,20]. ... In CdSe nanosheets, the surface is polarized, which could .... layer structure is not distorted drastically in comparison to the.

  1. AC electrical conductivity in amorphous indium selenide thin films

    International Nuclear Information System (INIS)

    Di Giulio, H.; Rella, R.; Tepore, A.

    1987-01-01

    In order to obtain additional information about the nature of the conduction mechanism in amorphous InSe films results of an experimental study concerning the frequency and temperature dependence of the ac conductivity are reported. The measurements were performed on specimens of different thickness and different electrode contact areas. The results can be explained assuming that conduction occurs by phonon-assisted hopping between localized states near the Fermi level

  2. Reversibility windows in selenide-based chalcogenide glasses

    International Nuclear Information System (INIS)

    Shpotyuk, O.; Hyla, M.; Boyko, V.; Golovchak, R.

    2008-01-01

    A simple route for the estimation of the reversibility windows in the sense of non-ageing ability is developed for chalcogenide glasses obeying '8-N' rule at the example of As-Se, Ge-Se and Ge-As-Se glass systems. The low limit of their reversibility windows is determined at the average coordination number Z=2.4 in full agreement with rigidity percolation theory, while the upper limit is shown to be related to the glass preparation conditions and samples prehistory

  3. Reversibility windows in selenide-based chalcogenide glasses

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, O. [Lviv Scientific Research Institute of Materials of SRC ' Carat' , 202, Stryjska Street, Lviv, UA 79031 (Ukraine); Institute of Physics of Jan Dlugosz University, 13/15, al. Armii Krajowej, Czestochowa, PL 42200 (Poland); Hyla, M. [Institute of Physics of Jan Dlugosz University, 13/15, al. Armii Krajowej, Czestochowa, PL 42200 (Poland); Boyko, V. [Lviv Scientific Research Institute of Materials of SRC ' Carat' , 202, Stryjska Street, Lviv, UA 79031 (Ukraine); Lviv National Polytechnic University, 12, Bandera Street, Lviv, UA 79013 (Ukraine); Golovchak, R. [Lviv Scientific Research Institute of Materials of SRC ' Carat' , 202, Stryjska Street, Lviv, UA 79031 (Ukraine)], E-mail: golovchak@novas.lviv.ua

    2008-10-01

    A simple route for the estimation of the reversibility windows in the sense of non-ageing ability is developed for chalcogenide glasses obeying '8-N' rule at the example of As-Se, Ge-Se and Ge-As-Se glass systems. The low limit of their reversibility windows is determined at the average coordination number Z=2.4 in full agreement with rigidity percolation theory, while the upper limit is shown to be related to the glass preparation conditions and samples prehistory.

  4. Selenidation of epitaxial silicene on ZrB2

    NARCIS (Netherlands)

    Wiggers, F. B.; Yamada-Takamura, Y.; Kovalgin, A. Y.; de Jong, M. P.

    2018-01-01

    The deposition of elemental Se on epitaxial silicene on ZrB2 thin films was investigated with synchrotron-based core-level photoelectron spectroscopy and low-energy electron diffraction. The deposition of Se at room temperature caused the appearance of Si 2p peaks with chemical shifts of n × 0.51 ±

  5. Electronic transport in bismuth selenide in the topological insulator regime

    Science.gov (United States)

    Kim, Dohun

    The 3D topological insulators (TIs) have an insulating bulk but spin-momentum coupled metallic surface states stemming from band inversion due to strong spin-orbit interaction, whose existence is guaranteed by the topology of the band structure of the insulator. While the STI surface state has been studied spectroscopically by e.g. photoemission and scanned probes, transport experiments have failed to demonstrate clear signature of the STI due to high level of bulk conduction. In this thesis, I present experimental results on the transport properties of TI material Bi2Se3 in the absence of bulk conduction (TI regime), achieved by applying novel p-type doping methods. Field effect transistors consisting of thin (thickness: 5-17 nm) Bi2Se3 are fabricated by mechanical exfoliation of single crystals, and a combination of conventional dielectric (300 nm thick SiO2) and electrochemical or chemical gating methods are used to move the Fermi energy through the surface Dirac point inside bulk band gap, revealing the ambipolar gapless nature of transport in the Bi2Se3 surface states. The minimum conductivity of the topological surface state is understood within the self-consistent theory of Dirac electrons in the presence of charged impurities. The intrinsic finite-temperature resistivity of the topological surface state due to electron-acoustic phonon scattering is measured to be 60 times larger than that of graphene largely due to the smaller Fermi and sound velocities in Bi2Se 3, which will have implications for topological electronic devices operating at room temperature. Along with semi-classical Boltzmann transport, I also discuss 2D weak anti-localization (WAL) behavior of the topological surface states. By investigating gate-tuned WAL behavior in thin (5-17 nm) TI films, I show that WAL in the TI regime is extraordinarily sensitive to the hybridization induced quantum mechanical tunneling between top and bottom topological surfaces, and interplay of phase coherence time and inter-surface tunneling time results in a crossover from two decoupled (top and bottom) symplectic 2D metal surfaces to a coherently coupled single channel. Furthermore, a complete suppression of WAL is observed in the 5 nm thick Bi2Se 3 film which was found to occur when the hybridization gap becomes comparable to the disorder strength.

  6. Synthesis of layered sodium lanthanum selenide through ion exchange reactions

    International Nuclear Information System (INIS)

    Butts, Laura J.; Strickland, Nicholas; Martin, Benjamin R.

    2009-01-01

    Layered hexagonal KLaSe2 (α-NaFeO 2 -type) was synthesized using the reactive flux method and analyzed by powder XRD to determine its lattice constants (space group R-3m, a = 4.40508(5) A, c = 22.7838(5) A). NaLaSe 2 , which normally crystallizes as a disordered rock salt structure with mixed Na+/La + 3 sites, was synthesized through a solid state ion exchange reaction at 585 deg. C from a 1:3 molar ratio mixture of KLaSe 2 :NaI. The product of this reaction was hexagonally layered NaLaSe 2 (space group R-3m, a = 4.3497(3) A, c = 20.808(2) A) isostructural to KLaSe 2 . This product was analyzed by comparison with members of the set of solid solutions Na (1-x) K (x) LaSe 2 to confirm that the extent ion exchange in this reaction was complete. Cubic (disordered) NaLaSe 2 was also reacted with KI to yield the poorly crystalline hexagonally layered product with the approximate formula Na 0.79 K 0.21 LaSe 2

  7. Selenide isotope generator for the Galileo mission. GDS disassembly report

    International Nuclear Information System (INIS)

    1978-11-01

    The GDS-1 was disassembled to determine the cause for the rapid degradation of the output power. Unfortunately, it was not possible to relate the observations to direct causes for the degradation. However, some positive statements can be made which have an impact on the flight program. First, the outgassing and gas management techniques were shown to be adequate to maintain clean conditions within the generator. Second, the non-modular components within the generator including the receptacles on the housing were not affected by the thermal environment during operation of GDS-1. Third, a significant amount of sublimation of the P-legs has occurred during the relatively short life of 2000 + hours as shown by the bullet nosing of the legs and deposits on the cold end hardware. The fact that the generator atmosphere was not 100% xenon may have some bearing on this observation but the statement is still accurate. Fourth, all exposed N-legs display cracks and/or chips. Fifth, a great deal of misalignment of both N and P-legs was seen both visually and with radiographs. Although no definite conclusions can be made concerning the cause for the rapid degradation of performance, several of the observed conditions within the module could possibly contribute to that fact. They are: cracks in N-legs (increased resistance); deposits on edges of BeO discs (shorting of thermoelectric circuit); and bullet nosing of P-legs (increased resistance). It remains to be shown if any of these effects or the follower hangup described earlier contributed to the poor performance of GDS-1 or if another effect as yet unknown was the important factor

  8. Ab initio transport across bismuth selenide surface barriers

    KAUST Repository

    Narayan, Awadhesh

    2014-11-24

    © 2014 American Physical Society. We investigate the effect of potential barriers in the form of step edges on the scattering properties of Bi2Se3(111) topological surface states by means of large-scale ab initio transport simulations. Our results demonstrate the suppression of perfect backscattering, while all other scattering processes, which do not entail a complete spin and momentum reversal, are allowed. Furthermore, we find that the spin of the surface state develops an out-of-plane component as it traverses the barrier. Our calculations reveal the existence of quasibound states in the vicinity of the surface barriers, which appear in the form of an enhanced density of states in the energy window corresponding to the topological state. For double barriers we demonstrate the formation of quantum well states. To complement our first-principles results we construct a two-dimensional low-energy effective model and illustrate its shortcomings. Our findings are discussed in the context of a number of recent experimental works.

  9. Bath parameter dependence of chemically deposited Copper Selenide thin film

    International Nuclear Information System (INIS)

    Al-Mamun; Islam, A.B.M.O.

    2004-09-01

    In this article, a low cost chemical bath deposition (CBD) technique has been used for the preparation Of Cu 2-x Se thin films on to glass substrate. Different thin fms (0.2-0.6/μm) were prepared by adjusting the bath parameter like concentration of ammonia, deposition time, temperature of the solution, and the ratios of the mixing composition between copper and selenium in the reaction bath. From these studies, it reveals that at low concentration of ammonia or TEA, the terminal thicknesses of the films are less, which gradually increases with the increase of concentrations and then drop down at still higher concentrations. It has been found that completing the Cu 2+ ions with EA first, and then addition of ammonia yields better results than the reverse process. The film thickness increases with the decrease of value x of Cu 2-x Se. (author)

  10. Sulfide, selenide and telluride glassy systems for optoelectronic applications

    Czech Academy of Sciences Publication Activity Database

    Ležal, Dimitrij; Zavadil, Jiří; Procházka, M.

    2005-01-01

    Roč. 7, č. 5 (2005), 2281-2291 ISSN 1454-4164 R&D Projects: GA ČR(CZ) GA104/05/0878 Institutional research plan: CEZ:AV0Z20670512 Keywords : transmission * fluorescence spectroscopy * chalcogenide glasses * optical properties Subject RIV: CA - Inorganic Chemistry Impact factor: 1.138, year: 2005

  11. Iron-Doped Zinc Selenide: Spectroscopy and Laser Development

    Science.gov (United States)

    2014-03-27

    pulsed and CW platforms have been continuously tuned across the whole gain bandwidth of Cr:ZnSe using dispersive tuning elements [9, 13, 14]. Lasers...induced fluorescence studies of the upper state manifold of Fe:ZnSe. 3.2 Laser-Induced Fluorescence Spectroscoscopy of Fe:ZnSe A Cryo Industries of...that temperature was recorded to provide a basis for calculation of the spectral distribution of gain. The recorded spectrum was black- body

  12. Electrical properties of silver selenide thin films prepared by reactive ...

    Indian Academy of Sciences (India)

    Unknown

    2001-07-29

    Jul 29, 2001 ... tion of a given vapour at a given rate takes place only if the temperature of ... temperature for evaporation of compound and subsequent decomposition ... Electrical conductivity and Hall effect measurements were carried out ...

  13. Selenide isotope generator for the Galileo Mission: safety test plan

    International Nuclear Information System (INIS)

    1979-01-01

    The intent of this safety test plan is to outline particular kinds of safety tests designed to produce information which would be useful in the safety analysis process. The program deals primarily with the response of the RTG to accident environments; accordingly two criteria were established: (1) safety tests should be performed for environments which are the most critical in terms of risk contribution; and (2) tests should be formulated to determine failure conditions for critical heat source components rather than observe heat source response in reference accident environments. To satisfy criterion 1. results of a recent safety study were used to rank various accidents in terms of expected source terms. Six kinds of tests were then proposed which would provide information meeting the second criterion

  14. Vertically aligned zinc selenide nanoribbon arrays: microstructure and field emission

    International Nuclear Information System (INIS)

    Zhao Lijuan; Pang Qi; Cai Yuan; Wang Ning; Ge Weikun; Wang Jiannong; Yang Shihe

    2007-01-01

    Uniform ZnSe precursor (ZnSe : 0.38en, en = ethylenediamine) nanoribbon arrays are grown vertically on Zn foils in ethylenediamine (en) using a solvothermal method. After the annealing treatment in N 2 , the ZnSe nanoribbon arrays can be obtained without an obvious morphology change and the crystallinity of ribbons is greatly improved. The microstructures of both individual ZnSe precursor and ZnSe nanoribbons are investigated. Field emission characteristics show that the onset field required drawing a current density of ∼0.1 μ A cm -2 from the ZnSe nanoribbons is 5.0 V μm -1 and the field enhancement factors are determined to be ∼1382

  15. Short-range order of germanium selenide glass

    Indian Academy of Sciences (India)

    Carlo (RMC) simulations are useful to compute the partial pair distribution ... recent times,13 the sorption ability of Ge20Se80 thin films, ... and the structural configuration is adjusted so as to mini- ... it is accepted with probability exp(−(χ2 n − χ2.

  16. Ab initio transport across bismuth selenide surface barriers

    KAUST Repository

    Narayan, Awadhesh; Rungger, Ivan; Droghetti, Andrea; Sanvito, Stefano

    2014-01-01

    © 2014 American Physical Society. We investigate the effect of potential barriers in the form of step edges on the scattering properties of Bi2Se3(111) topological surface states by means of large-scale ab initio transport simulations. Our results

  17. Adsorption of dysprosium on the graphite (0001) surface: Nucleation and growth at 300 K

    International Nuclear Information System (INIS)

    Kwolek, Emma J.; Lii-Rosales, Ann; Lei, Huaping; Wang, Cai-Zhuang; Tringides, Michael C.; Evans, James W.; Wallingford, Mark; Zhou, Yinghui; Thiel, Patricia A.

    2016-01-01

    We have studied nucleation and growth of Dy islands on the basal plane of graphite at 300 K using scanning tunneling microscopy, density functional theory (DFT) in a form that includes van der Waals interactions, and analytic theory. The interaction of atomic Dy with graphite is strong, while the diffusion barrier is small. Experiment shows that at 300 K, the density of nucleated islands is close to the value predicted for homogeneous nucleation, using critical nucleus size of 1 and the DFT-derived diffusion barrier. Homogeneous nucleation is also supported by the monomodal shape of the island size distributions. Comparison with the published island density of Dy on graphene shows that the value is about two orders of magnitude smaller on graphite, which can be attributed to more effective charge screening in graphite. The base of each island is 3 atomic layers high and atomically ordered, forming a coincidence lattice with the graphite. Islands resist coalescence, probably due to multiple rotational orientations associated with the coincidence lattice. Upper levels grow as discernible single-atom layers. Analysis of the level populations reveals significant downward interlayer transport, which facilitates growth of the base. This island shape is metastable, since more compact three-dimensional islands form at elevated growth temperature.

  18. Dysprosium separation from aqueous phase by non-dispersive solvent extraction employing hollow fibre membrane module

    International Nuclear Information System (INIS)

    Yadav, Kartikey K.; Singh, D.K.; Kain, V.

    2017-01-01

    Rare earth elements (REEs) consist of fourteen lanthanides and three elements which are Sc, Y and La resulting in total 17 REEs. In the last decade, these rare earths elements which have unique physical and chemical properties have been highly in demand for their application in almost all walks of life. Various methods such as ion exchange, precipitation and solvent extraction have been used to recover these elements from aqueous solutions. These traditional methods have some inherent disadvantages like handling of hazardous organic chemicals, ineffectiveness to recover a very low concentration of contaminated source etc. In this regard, an important method i.e. liquid membrane offers separation scheme; which combines the characteristics, of solvent extraction and solid membrane separation, to overcome the disadvantages of conventional techniques. Various experiments were carried out to evaluate the effect of feed acidity, metal ion concentration, carrier concentration, feed composition, flow rates and phase ratio on the transport of rare earths metal ions across the membrane

  19. Manufacturing of Dysprosium-Iron Alloys by Electrolysis in Fluoride-Based Electrolytes: Oxide Solubility Determinations

    Science.gov (United States)

    Martinez, Ana Maria; Støre, Anne; Osen, Karen Sende

    2018-04-01

    Electrolytic production of light rare earth elements and alloys takes place in a fluoride-based electrolyte using rare earth oxides as raw material. The optimization of this method, mainly in terms of the energy efficiency and environmental impact control, is rather challenging. Anode effects, evolution of fluorine-containing compounds, and side cathode reactions could largely be minimized by a good control of the amount of rare earth oxide species dissolved in the fluoride-based electrolyte and their dissolution rate. The oxide content of the fluoride melts REF3-LiF (RE = Nd, Dy) at different compositions and temperatures were experimentally determined by carbothermal analysis of melt samples. The highest solubility values of oxide species, added as Dy2O3 and Dy2(CO3)3, were obtained to be of ca. 3 wt pct (expressed as Dy2O3) in the case of the equimolar DyF3-LiF melt at 1323 K (1050 °C). The oxide saturation values increased with the amount of REF3 present in the molten bath and the working temperature.

  20. A naproxen complex of dysprosium intercalates into calf thymus DNA base pairs

    International Nuclear Information System (INIS)

    Yang, Mengsi; Jin, Jianhua; Xu, Guiqing; Cui, Fengling; Luo, Hongxia

    2014-01-01

    Highlights: • Binding mode to ctDNA was studied by various methods. • Intercalation is the most possible binding mode. • Dynamic and static quenching occurred simultaneously. • Hydrophobic force played a major role. • Binding characteristic of rare earth complexes to DNA are dependent on the element. - Abstract: The binding mode and mechanism of dysprosium–naproxen complex (Dy–NAP) with calf thymus deoxyribonucleic acid (ctDNA) were studied using UV–vis and fluorescence spectra in physiological buffer (pH 7.4). The results showed that more than one type of quenching process occurred and the binding mode between Dy–NAP with ctDNA might be intercalation. In addition, ionic strength, iodide quenching and fluorescence polarization experiments corroborated the intercalation binding mode between Dy–NAP and ctDNA. The calculated thermodynamic parameters ΔG, ΔH and ΔS at different temperature demonstrated that hydrophobic interaction force played a major role in the binding process

  1. White light emission and color tunability of dysprosium doped barium silicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Lokesh; Sharma, Anchal; Vishwakarma, Amit K.; Jha, Kaushal [Department of Applied Physics, Delhi Technological University, Delhi 110042 (India); Jayasimhadri, M., E-mail: jayaphysics@yahoo.com [Department of Applied Physics, Delhi Technological University, Delhi 110042 (India); Ratnam, B.V.; Jang, Kiwan [Department of Physics, Changwon National University, Changwon 641-77 (Korea, Republic of); Rao, A.S.; Sinha, R.K. [Department of Applied Physics, Delhi Technological University, Delhi 110042 (India)

    2016-01-15

    The present work elucidates the synthesis of Dy{sup 3+} doped barium silicate glasses, along with the subsequent studies performed to evaluate its viability in solid state lighting applications. The synthesized photonic glasses were investigated via X-Ray Diffraction, Scanning Electron Microscopy and Fourier Transform Infrared Spectroscopy. The photoluminescence properties were examined under ultraviolet (UV)/near UV (NUV) excitation. Photoluminescence spectrum exhibited characteristic emission bands at λ{sub em}=483 nm (blue) and λ{sub em}=576 nm (yellow) which are ascribed to the {sup 4}F{sub 9/2}→{sup 6}H{sub 15/2} and {sup 4}F{sub 9/2}→{sup 6}H{sub 13/2} transitions of Dy{sup 3+} ion, respectively. The chromaticity coordinates under excitation of λ{sub ex}=348 nm are (0.31, 0.34), which lies in the white region of CIE 1931 chromaticity diagram and are in excellent proximity with the standard equal energy white illuminant (0.333, 0.333). The calculated correlated color temperature and the yellow to blue (Y/B) ratio are found to be 6602 K and 1.12, respectively for the optimized sample. The synthesized photonic glass also offered the possibility of tuning the color as exemplified through the variation in CIE coordinates, correlated color temperature and the Y/B ratio. The results confirm the possibility of color tunability from the proposed glass and may be useful for various photonic device applications. - Highlights: • Successfully synthesized Dy{sup 3+} doped barium silicate glasses. • Structural properties thoroughly discussed by using XRD and FT-IR. • Photoluminescence and colorimetry properties have been investigated. • Y/B ratio and the reason for color tunability have been successfully explained. • CIE coordinates of Dy{sup 3+}:BBS glass confirm its suitability for w-LEDs.

  2. New ultrasonic attenuation maxima for single crystal dysprosium in a magnetic field

    International Nuclear Information System (INIS)

    Treder, R.A.; Maekawa, S.; Levy, M.

    1976-01-01

    The temperatures and corresponding applied basal plane magnetic fields are reported for longitudinal ultrasonic attenuation maxima in a cylindrical Dy sample. Besides maxima at Tsub(N) and Tsub(C), two new maxima are observed and possible explanations for their existence are given. (Auth.)

  3. Adsorption of dysprosium on the graphite (0001) surface: Nucleation and growth at 300 K

    Energy Technology Data Exchange (ETDEWEB)

    Kwolek, Emma J.; Lii-Rosales, Ann [The Ames Laboratory, Ames, Iowa 50011 (United States); Department of Chemistry, Iowa State University, Ames, Iowa 50011 (United States); Lei, Huaping; Wang, Cai-Zhuang; Tringides, Michael C.; Evans, James W. [The Ames Laboratory, Ames, Iowa 50011 (United States); Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States); Wallingford, Mark; Zhou, Yinghui [The Ames Laboratory, Ames, Iowa 50011 (United States); Thiel, Patricia A., E-mail: pthiel@iastate.edu [The Ames Laboratory, Ames, Iowa 50011 (United States); Department of Chemistry, Iowa State University, Ames, Iowa 50011 (United States); Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011 (United States)

    2016-12-07

    We have studied nucleation and growth of Dy islands on the basal plane of graphite at 300 K using scanning tunneling microscopy, density functional theory (DFT) in a form that includes van der Waals interactions, and analytic theory. The interaction of atomic Dy with graphite is strong, while the diffusion barrier is small. Experiment shows that at 300 K, the density of nucleated islands is close to the value predicted for homogeneous nucleation, using critical nucleus size of 1 and the DFT-derived diffusion barrier. Homogeneous nucleation is also supported by the monomodal shape of the island size distributions. Comparison with the published island density of Dy on graphene shows that the value is about two orders of magnitude smaller on graphite, which can be attributed to more effective charge screening in graphite. The base of each island is 3 atomic layers high and atomically ordered, forming a coincidence lattice with the graphite. Islands resist coalescence, probably due to multiple rotational orientations associated with the coincidence lattice. Upper levels grow as discernible single-atom layers. Analysis of the level populations reveals significant downward interlayer transport, which facilitates growth of the base. This island shape is metastable, since more compact three-dimensional islands form at elevated growth temperature.

  4. An operationally simple method for separating the rare-earth elements neodymium and dysprosium

    Energy Technology Data Exchange (ETDEWEB)

    Bogart, Justin A.; Lippincott, Connor A.; Carroll, Patrick J.; Schelter, Eric J. [Department of Chemistry, University of Pennsylvania, Philadelphia, PA (United States)

    2015-07-06

    Rare-earth metals are critical components of electronic materials and permanent magnets. Recycling of consumer materials is a promising new source of rare earths. To incentivize recycling there is a clear need for simple methods for targeted separations of mixtures of rare-earth metal salts. Metal complexes of a tripodal nitroxide ligand [{(2-"tBuNO)C_6H_4CH_2}{sub 3}N]{sup 3-} (TriNOx{sup 3-}), feature a size-sensitive aperture formed of its three η{sup 2}-(N,O) ligand arms. Exposure of metal cations in the aperture induces a self-associative equilibrium comprising [M(TriNOx)thf]/[M(TriNOx)]{sub 2} (M=rare-earth metal). Differences in the equilibrium constants (K{sub eq}) for early and late metals enables simple Nd/Dy separations through leaching with a separation ratio S{sub Nd/Dy}=359. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. An Operationally Simple Method for Separating the Rare-Earth Elements Neodymium and Dysprosium.

    Science.gov (United States)

    Bogart, Justin A; Lippincott, Connor A; Carroll, Patrick J; Schelter, Eric J

    2015-07-06

    Rare-earth metals are critical components of electronic materials and permanent magnets. Recycling of consumer materials is a promising new source of rare earths. To incentivize recycling there is a clear need for simple methods for targeted separations of mixtures of rare-earth metal salts. Metal complexes of a tripodal nitroxide ligand [{(2-(t) BuNO)C6 H4 CH2 }3 N](3-) (TriNOx(3-) ), feature a size-sensitive aperture formed of its three η(2) -(N,O) ligand arms. Exposure of metal cations in the aperture induces a self-associative equilibrium comprising [M(TriNOx)thf]/ [M(TriNOx)]2 (M=rare-earth metal). Differences in the equilibrium constants (Keq ) for early and late metals enables simple Nd/Dy separations through leaching with a separation ratio SNd/Dy =359. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Cerium: an unlikely replacement of dysprosium in high performance Nd-Fe-B permanent magnets.

    Science.gov (United States)

    Pathak, Arjun K; Khan, Mahmud; Gschneidner, Karl A; McCallum, Ralph W; Zhou, Lin; Sun, Kewei; Dennis, Kevin W; Zhou, Chen; Pinkerton, Frederick E; Kramer, Matthew J; Pecharsky, Vitalij K

    2015-04-24

    Replacement of Dy and substitution of Nd in NdFeB-based permanent magnets by Ce, the most abundant and lowest cost rare earth element, is important because Dy and Nd are costly and critical rare earth elements. The Ce, Co co-doped alloys have excellent high-temperature magnetic properties with an intrinsic coercivity being the highest known for T ≥ 453 K. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. A Linear Tetranuclear Dysprosium(III) Compound Showing Single-Molecule Magnet Behavior

    Energy Technology Data Exchange (ETDEWEB)

    Ke, Hongshan; Xu, Gong Feng; Guo, Yun-Nan; Gamez, Patrick; Beavers, Christine M; Teat, Simon J; Tang, Jinkui

    2010-04-20

    Although magnetic measurements reveal a single-relaxation time for a linear tetranuclear Dy(III) compound, the wide distribution of the relaxation time observed clearly suggests the presence of two slightly different anisotropic centres, therefore opening new avenues for investigating the relaxation dynamics of lanthanide aggregates.

  8. Experimental study of induced staggered magnetic fields in dysprosium gallium garnet (DGG)

    International Nuclear Information System (INIS)

    Steiner, M.; Corliss, L.M.; Hastings, J.M.; Blume, M.; Giordano, N.; Wolf, W.P.

    1979-01-01

    Neutron diffraction techniques have been used to study induced staggered magnetic field effects in DGG. The application of a uniform magnetic field at temperatures much greater than the Neel temperature induces a significant amount of antiferromagnetic order. The temperature and field dependences of this effect are in good agreement with recent theoretical predicions

  9. Influence of dysprosium and terbium additions on aluminium structure and properties

    International Nuclear Information System (INIS)

    Fridlyander, I.N.; Sokolovskaya, E.M.; Zimina, E.N.; Tkachenko, E.A.; Artemova, M.S.

    1992-01-01

    The influence of 0.3%Dy and 0.3%Tb additions were investigated on grain size in aluminium ingots and on recrystallization and mechanical properties in 1.5 mm thick sheets. Grain refinement in ingots was revealed along with an increase of sheet recrystallization temperature and grain growth retardation in the process of secondary recrystallization. Ultimate strength was found to rise at some decrease of specific elongation

  10. Improvement of high-frequency characteristics of Z-type hexaferrite by dysprosium doping

    International Nuclear Information System (INIS)

    Mu Chunhong; Liu Yingli; Song Yuanqiang; Wang Liguo; Zhang Huaiwu

    2011-01-01

    Z-type hexaferrite has great potential applications as anti-EMI material for magnetic devices in the GHz region. In this work, Dy-doped Z-type hexaferrites with nominal stoichiometry of Ba 3 Co 2 Dy x Fe 24-x O 41 (x 0.0, 0.05, 0.5, 1.0) were prepared by an improved solid-state reaction method. The effects of rare earth oxide (Dy 2 O 3 ) addition on the phase composition, microstructure and electromagnetic properties of the ceramics were investigated. Structure and micromorphology characterizations indicate that certain content of Dy doping will cause the emergence of the second phase Dy 3 Fe 5 O 12 at the grain boundaries of the majority phase Z-type hexaferrite, due to which the straightforward result is the grain refinement during the successive sintering process. Permeability spectra measurements show that the initial permeability reaches its maximum of 17 at 300 MHz with x = 0.5, while the cutoff frequency keeps above 800 MHz. The apparent specific anisotropy field H K of Dy-doped Z-type hexaferrites decreases with x increasing. The relationships among phase composition, grain size, permeability spectra, and anisotropy are theoretically investigated, and according to the analysis, Dy doping effects on its magnetic properties can be well explained and understood.

  11. Synthesis, photoluminescence and intramolecular energy transfer model of a dysprosium complex

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Aiqin; Zhang Jiuli; Pan Qiliang; Wang Shuhua [College of Materials Science and Engineering, Taiyuan University of Technology, No. 79 West Yingze Street, Taiyuan, Shanxi 030024 (China); Key Laboratory of Interface Science and Engineering in Advanced Materials of Taiyuan University of Technology, Ministry of Education, Taiyuan, Shanxi 030024 (China); Jia Husheng, E-mail: Jia_Husheng@126.com [College of Materials Science and Engineering, Taiyuan University of Technology, No. 79 West Yingze Street, Taiyuan, Shanxi 030024 (China) and Key Laboratory of Interface Science and Engineering in Advanced Materials of Taiyuan University of Technology, Ministry of Education, Taiyuan, Shanxi 030024 (China); Xu Bingshe [College of Materials Science and Engineering, Taiyuan University of Technology, No. 79 West Yingze Street, Taiyuan, Shanxi 030024 (China); Key Laboratory of Interface Science and Engineering in Advanced Materials of Taiyuan University of Technology, Ministry of Education, Taiyuan, Shanxi 030024 (China)

    2012-04-15

    The energy of the highest occupied molecular orbital and the lowest unoccupied molecular orbital as well as their energy gaps, and the singlet and triplet state energy levels of 4-benzoylbenzoic acid (HL=4-BBA) and triphenylphosphine oxide (TPPO) were calculated with the Gaussian03 program package. The singlet state and triplet state energy levels were also estimated from the UV-vis absorption spectra and phosphorescence spectra. The results suggest that the calculated values approximately coincided with the experimental values. A Dy(III) complex was synthesized with 4-BBA as primary ligand and TPPO as neutral ligand. The structure of the complex was characterized by elemental analysis, {sup 1}H NMR spectrometry, and FTIR spectrometry. TG-DTG analysis indicates that the complex kept stable up to 305 Degree-Sign C. The photoluminescence properties were studied by fluorescence spectrometry. The results show that Dy(III) ion sensitized by 4-BBA and TPPO emitted characteristic peaks at 572 nm ({sup 4}F{sub 9/2}-{sup 6}H{sub 13/2}) and 480 nm ({sup 4}F{sub 9/2}-{sup 6}H{sub 15/2}), and its Commission Internationale de L'Eclairge coordinates were calculated as x=0.33 and y=0.38, being located in the white range. Intermolecular energy transfer process was discussed and energy transfer model was also proposed. - Highlights: Black-Right-Pointing-Pointer Quantum calculation provides theoretical method of ligand choice for rare earth. Black-Right-Pointing-Pointer The complex Dy(L){sub 3}(TPPO){sub 2} emitted white light. Black-Right-Pointing-Pointer The CIE coordinates were calculated as x=0.33 and y=0.38. Black-Right-Pointing-Pointer Energy transfer in Dy(L){sub 3}(TPPO){sub 2} followed Dexter electron exchange theory.

  12. Crystal-field magnetic anisotropy of dilute dysprosium or erbium in yttrium single crystals

    DEFF Research Database (Denmark)

    Høg, J.; Touborg, P.

    1974-01-01

    Magnetization measurements have been performed between 1.3 and 300 K in fields up to 50 × 105 A/m in the a, b, and c directions of hcp crystals of pure Y and Y doped with 0.14-at.% Dy or 0.14-at.% Er, using the Faraday method and a vibrating-sample method. The characteristic behavior of both...

  13. Extraction and stripping of neodymium (III) and dysprosium (III) by TRUEX solvent

    International Nuclear Information System (INIS)

    Rout, Alok; Venkatesan, K.A.; Antony, M.P.; Srinivasan, T.G.; Vasudeva Rao, P.R.

    2009-01-01

    McCabe-Thiele diagram for the extraction and stripping of Nd (III) and Dy (III) by TRUEX solvent has been constructed to determine the number of stages required for complete extraction and stripping. (author)

  14. Electron-beam nanosculpting and materials analysis of exfoliated bismuth selenide

    Science.gov (United States)

    Friedensen, Sarah; Parkin, William; Mlack, Jerome; Drndic, Marija

    We report on nanosculpting Bi2Se3 with a highly-focused electron beam in a scanning transmission electron microscope (STEM). Exfoliated Bi2Se3 flakes were transferred onto silicon nitride TEM windows and structures at least 100 nm by 100 nm in size were selected for shaping. Focused ion beam (FIB) cutting was used to carve larger features into the structures and provide preliminary thinning if desired. Then, a STEM probe was used to sculpt more delicate features, including nanowires of approximately 20 nm in width, point contacts, and T-shaped junctions. During STEM cutting, the structures were monitored using energy dispersive X-ray spectroscopy (EDS) mapping, electron diffraction, and high-resolution imaging, and it was found that the crystal structure remains largely intact. This process opens the way for in-situ determination of the effects of size and structure on electrical and thermal properties of Bi2Se3 and fabrication of nanodevices with more elaborate geometries than can be achieved with growth methods alone.

  15. Synthesis, structure and electrical properties of a new tin vanadium selenide

    Energy Technology Data Exchange (ETDEWEB)

    Atkins, Ryan, E-mail: atkins@uoregon.edu [Department of Chemistry and Materials Science Institute, University of Oregon, Eugene, OR 97403 (United States); Disch, Sabrina, E-mail: disch@ill.fr [Institut Laue-Langevin (ILL), F-38042 Grenoble (France); Jones, Zachary, E-mail: zjones@chem.ucsb.edu [Department of Chemistry and Materials Science Institute, University of Oregon, Eugene, OR 97403 (United States); Haeusler, Ines, E-mail: haeusler@physik.hu-berlin.de [Novel Materials, Humboldt-Universität zu Berlin, Newtonstr. 15, 12489 Berlin (Germany); Grosse, Corinna, E-mail: Corinna.Grosse@physik.hu-berlin.de [Novel Materials, Humboldt-Universität zu Berlin, Newtonstr. 15, 12489 Berlin (Germany); Fischer, Saskia F., E-mail: Saskia.Fischer@physik.hu-berlin.de [Novel Materials, Humboldt-Universität zu Berlin, Newtonstr. 15, 12489 Berlin (Germany); Neumann, Wolfgang, E-mail: wsn@uoregon.edu [Department of Chemistry and Materials Science Institute, University of Oregon, Eugene, OR 97403 (United States); Zschack, Paul, E-mail: zschack@bnl.gov [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States); Johnson, David C., E-mail: davej@uoregon.edu [Department of Chemistry and Materials Science Institute, University of Oregon, Eugene, OR 97403 (United States)

    2013-06-15

    The turbostratically disordered misfit layer compound (SnSe){sub 1.15}VSe{sub 2} was synthesized and structurally characterized. Electrical transport measurements suggest this compound undergoes a charge or spin density wave (CDW or SDW) transition, which has not been observed in previous misfit layer compounds. The (SnSe){sub 1.15}VSe{sub 2} compound, created through the modulated elemental reactants technique, contains highly oriented intergrowths of SnSe bilayers and VSe{sub 2} structured Se–V–Se trilayers with abrupt interfaces between them perpendicular to the c-axis. X-ray diffraction data and transmission electron microscope images show that each constituent has in-plane crystallinity but that there is a random rotational disorder between the constituent layers. Temperature-dependent electrical resistivity data and Hall measurements are consistent with (SnSe){sub 1.15}VSe{sub 2} being a metal, however an abrupt increase in the resistivity occurs between 30 and 100 K. The carrier concentration decreases by approximately 1 carrier per vanadium atom during this temperature interval. - Graphical abstract: Turbostratically disordered (SnSe){sub 1.15}VSe{sub 2}. - Highlights: • New compound (SnSe){sub 1.15}VSe{sub 2}. • Turbostratic disorder. • Charge density wave at 100 K.

  16. Weak antilocalization and low-temperature characterization of sputtered polycrystalline bismuth selenide

    Science.gov (United States)

    Sahu, Protyush; Chen, Jun-Yang; Myers, Jason C.; Wang, Jian-Ping

    2018-03-01

    We report a thorough crystal and transport characterization of sputtered polycrystalline BixSe1 -x (20 nm), grown on a thermally oxidized silicon substrate. The crystal and grain structures of the sample are characterized by transmission electron microscopy. Selected-area electron diffraction shows a highly polycrystalline structure. Transport measurements suggest semiconducting behavior of the BixSe1 -x film with a very high carrier concentration (˜1020 cm3) and low mobility [˜8 cm2/(V s)]. High-field magnetoresistance measurements reveal weak antilocalization, to which both the low mobility and the angular dependence suggest an impurity-dominated contribution. Fitting parameters are obtained from 2D magnetoconductivity using the Hikami-Larkin-Nagaoka equation. The variation of the phase coherence length with temperature suggests electron-electron scattering for phase decoherence. Electron-electron interaction theory is used to analyze the low-temperature conductivity.

  17. Selenide isotope generators for the Galileo Mission: SIG hermetic bimetal weld transition joint

    International Nuclear Information System (INIS)

    Barnett, W.J.

    1979-08-01

    The successful development of the commercial 6061-T651/Silver/304L explosive clad plate material as a bimetal weld transition joint material, as described herein, satisfies all SIG Galileo design requirements for hermetic weld attachment of stainless steel subassemblies to aluminum alloy generator housing or end cover structures. The application of this type weld transition joint to the hermetic attachment of stainless steel shell connectors is well-developed and tested. Based on on-going life tests of stainless steel receptacle/bimetal ring attachment assemblies and metallurgical characterization studies of this transition joint material, it appears evident that this transition joint material has more than adequate capability to meet the 250 to 300 0 F and 50,000 hr. design life of the SIG/Galileo mission. Its extended life temperture capability may well approach 350 to 400 0 F

  18. Selenide isotope generator for the Galileo Mission: SIG thermal insulation evaluaion tests

    International Nuclear Information System (INIS)

    1979-06-01

    Since the SIG program required the use of very high performance thermal insulation materials in rather severe thermal and environmental conditions, a thorough screening and testing program was performed. Several types of materials were included in the preliminary survey. Most promising were oxide and carbonaceous fibrous insulations, oxide and carbonaceous foamed materials, and multilayer materials with both powder and cloth spacers. The latter were only viable for the vacuum option. In all, over one hundred materials from more than sixty manufacturers were evaluated from literature and manufacturers' data. The list was pared to eighteen candidates in seven basic types, i.e., fibrous microporous SiO 2 , fibrous SiO 2 /Al 2 O 3 , fibrous ZrO 2 , fibrous carbon, foamed SiO 2 , foamed carbon, and multilayer. Test results are presented

  19. Synthesis and characterization of rare-earth oxide transition-metal arsenides and selenides

    Energy Technology Data Exchange (ETDEWEB)

    Peschke, Simon Friedrich

    2017-04-06

    The present thesis includes two different quaternary systems that have been studied extensively. On the one hand, several samples of the REFeAsO{sub 1-x}F{sub x} family of iron-based superconductors were prepared using a novel solid state metathesis reaction, which also provided a possibility to prepare late rare-earth compounds of this family at ambient pressure. Comparison of structural and physical properties of those samples with samples from conventional solid state and high pressure syntheses revealed both, commonalities as well as striking differences. The observations gave reason to the conclusion that superconducting properties strongly depend, beside electronic infl uence, on the structural parameters. On the other hand, the quaternary system RE-T-Se-O with T = Ti-Mn was investigated using a NaI/KI flux mediated synthesis route. It has been shown that oC -La{sub 2}O{sub 2}MnSe{sub 2} is exclusively accessible in su fficient purity by the use of a fl ux material. Therefore, further syntheses in this quaternary system were performed by a flux mediated synthesis route leading to a large amount of new materials. Among them, a new polymorph mC-La{sub 2}O{sub 2}MnSe{sub 2} which forms, together with La{sub 4}MnSe{sub 3}O{sub 4} and La{sub 6}MnSe{sub 4}O{sub 6}, the series La{sub 2n+2}MnSe{sub n+2}O{sub 2n+2}. In addition, the alternative preparation method also enabled a large scale synthesis of the first examples of rare-earth chromium oxyselenides with chromium in the oxidation state +II, namely RE{sub 2}CrSe{sub 2}O{sub 2} (RE = La-Nd), which opened the door to study their magnetism in detail by powder neutron diffraction and muon spin rotation techniques. Research into the La-V-Se-O system revealed the first fi ve quaternary compounds of this family with interesting magnetic properties including ferromagnetism, antiferromagnetism, metamagnetism and more complex behaviour. In addition, the crystal structure of two new quaternary titanium containing oxyselenides were identifi ed and revealed unique structural building blocks that have not been observed in these systems before. The results of this thesis demonstrate not only the power of alternative preparation methods, but also the still increasing structural variety in the discussed quaternary systems. Strategic research in the field of transition-metal oxypnictides and oxychalcogenides, which still include a multiplicity of unknown materials, revealed numerous compounds with interesting physical properties and further investigations will probably uncover also new superconducting materials.

  20. Interaction between crystal lattice and mobile ions in copper selenides studied by EXAFS spectroscopy

    International Nuclear Information System (INIS)

    Asylgushina, G.N.; Bikkulova, N.N.; Titova, S.G.; Kochubey, D.I.

    2005-01-01

    Interaction between crystal lattice and mobile Cu ions has been studied in Cu 2- x Se in superionic and in normal state using EXAFS-spectroscopy. It has been found that the transition from normal to superionic state and change of mobile Cu ion concentration practically do not have an influence on local state of Cu atoms, but change of both these parameters is accompanied by a change of Se-sublattice state

  1. Electronic structure of germanium selenide investigated using ultra-violet photo-electron spectroscopy

    Science.gov (United States)

    Mishra, P.; Lohani, H.; Kundu, A. K.; Patel, R.; Solanki, G. K.; Menon, Krishnakumar S. R.; Sekhar, B. R.

    2015-07-01

    The valence band electronic structure of GeSe single crystals has been investigated using angle resolved photoemission spectroscopy (ARPES) and x-ray photoelectron spectroscopy. The experimentally observed bands from ARPES, match qualitatively with our LDA-based band structure calculations along the Γ-Z, Γ-Y and Γ-T symmetry directions. The valence band maximum occurs nearly midway along the Γ-Z direction, at a binding energy of -0.5 eV, substantiating the indirect band gap of GeSe. Non-dispersive features associated with surface states and indirect transitions have been observed. The difference in hybridization of Se and Ge 4p orbitals leads to the variation of dispersion along the three symmetry directions. The predominance of the Se 4pz orbitals, evidenced from theoretical calculations, may be the cause for highly dispersive bands along the Γ-T direction. Detailed electronic structure analysis reveals the significance of the cation-anion 4p orbitals hybridization in the valence band dispersion of IV-VI semiconductors. This is the first comprehensive report of the electronic structure of a GeSe single crystal using ARPES in conjugation with theoretical band structure analysis.

  2. Physical ageing in the above-bandgap photoexposured glassy arsenic selenides

    Energy Technology Data Exchange (ETDEWEB)

    Kozdras, A [Faculty of Physics of Opole University of Technology, 75, Ozimska str., Opole, PL-45370 (Poland); Golovchak, R [Lviv Scientific Research Institute of Materials of SRC ' Carat' , 202, Stryjska str., Lviv, UA-79031 (Ukraine); Shpotyuk, O [Lviv Scientific Research Institute of Materials of SRC ' Carat' , 202, Stryjska str., Lviv, UA-79031 (Ukraine)

    2007-08-15

    Physical ageing induced by above-bandgap light illumination is studied in glassy As-Se using differential scanning calorimetry. It is shown that measurable effect like to known short-term physical ageing is observed only in Se-rich glasses. The kinetics of this effect is compared with that caused by natural storage in a dark.

  3. Physical ageing in the above-bandgap photoexposured glassy arsenic selenides

    International Nuclear Information System (INIS)

    Kozdras, A; Golovchak, R; Shpotyuk, O

    2007-01-01

    Physical ageing induced by above-bandgap light illumination is studied in glassy As-Se using differential scanning calorimetry. It is shown that measurable effect like to known short-term physical ageing is observed only in Se-rich glasses. The kinetics of this effect is compared with that caused by natural storage in a dark

  4. Pseudo-self-organized topological phases in glassy selenides for IR photonics

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, O. [Lviv Institute of Materials of Scientific Research Company ' ' Carat' ' 202, Stryjska str., 79031 Lviv (Ukraine); Institute of Physics of Jan Dlugosz University 13/15, al. Armii Krajowej, 42201 Czestochowa (Poland); Golovchak, R. [Lviv Institute of Materials of Scientific Research Company ' ' Carat' ' 202, Stryjska str., 79031 Lviv (Ukraine)

    2011-09-15

    Network-forming cluster approach is applied to As-Se and Ge-Se glasses to justify their tendency to self-organization. It is shown that reversibility windows determined by temperature-modulated differential scanning calorimetry using short-term aged or as-prepared samples do not necessary coincide with self-organized phase in these materials. The obtained results testify also pseudo-self-organization phenomenon in Ge-Se glasses: over-constrained outrigger raft structural units built of two edge- and four corner-shared tetrahedra are interconnected via optimally-constrained {identical_to}Ge-Se-Se-Ge{identical_to} bridges within the range of compositions identified previously as self-organized phase by temperature modulated differential scanning calorimetry technique. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Step-wise kinetics of natural physical ageing in arsenic selenide glasses

    International Nuclear Information System (INIS)

    Golovchak, R; Kozdras, A; Balitska, V; Shpotyuk, O

    2012-01-01

    The long-term kinetics of physical ageing at ambient temperature is studied in Se-rich As-Se glasses using the conventional differential scanning calorimetry technique. It is analysed through the changes in the structural relaxation parameters occurring during the glass-to-supercooled liquid transition in the heating mode. Along with the time dependences of the glass transition temperature (T g ) and partial area (A) under the endothermic relaxation peak, the enthalpy losses (ΔH) and calculated fictive temperature (T F ) are analysed as key parameters, characterizing the kinetics of physical ageing. The latter is shown to have step-wise character, revealing some kinds of subsequent plateaus and steep regions. A phenomenological description of physical ageing in the investigated glasses is proposed on the basis of an alignment-shrinkage mechanism and first-order kinetic equations.

  6. Electronic structure and thermoelectric properties of bismuth telluride and bismuth selenide

    CERN Document Server

    Mishra, S K; Jepsen, O

    1997-01-01

    The electronic structures of the two thermoelectric materials Bi sub 2 Te sub 3 and Bi sub 2 Se sub 3 are studied using density-functional theory with the spin - orbit interaction included. The electron states in the gap region and the chemical bonding can be described in terms of pp sigma interaction between the atomic p orbitals within the 'quintuple' layer. For Bi sub 2 Se sub 3 , we find both the valence-band maximum as well as the conduction-band minimum, each with a nearly isotropic effective mass, to occur at the zone centre in agreement with experimental results. For Bi sub 2 Te sub 3 , we find that the six valleys for the valence-band maximum are located in the mirror planes of the Brillouin zone and they have a highly anisotropic effective mass, leading to an agreement between the de Haas-van Alphen data for the p-doped samples and the calculated Fermi surface. The calculated conduction band, however, has only two minima, instead of the six minima indicated from earlier experiments. The calculated S...

  7. Long-chain amine-templated synthesis of gallium sulfide and gallium selenide nanotubes

    Science.gov (United States)

    Seral-Ascaso, A.; Metel, S.; Pokle, A.; Backes, C.; Zhang, C. J.; Nerl, H. C.; Rode, K.; Berner, N. C.; Downing, C.; McEvoy, N.; Muñoz, E.; Harvey, A.; Gholamvand, Z.; Duesberg, G. S.; Coleman, J. N.; Nicolosi, V.

    2016-06-01

    We describe the soft chemistry synthesis of amine-templated gallium chalcogenide nanotubes through the reaction of gallium(iii) acetylacetonate and the chalcogen (sulfur, selenium) using a mixture of long-chain amines (hexadecylamine and dodecylamine) as a solvent. Beyond their role as solvent, the amines also act as a template, directing the growth of discrete units with a one-dimensional multilayer tubular nanostructure. These new materials, which broaden the family of amine-stabilized gallium chalcogenides, can be tentatively classified as direct large band gap semiconductors. Their preliminary performance as active material for electrodes in lithium ion batteries has also been tested, demonstrating great potential in energy storage field even without optimization.We describe the soft chemistry synthesis of amine-templated gallium chalcogenide nanotubes through the reaction of gallium(iii) acetylacetonate and the chalcogen (sulfur, selenium) using a mixture of long-chain amines (hexadecylamine and dodecylamine) as a solvent. Beyond their role as solvent, the amines also act as a template, directing the growth of discrete units with a one-dimensional multilayer tubular nanostructure. These new materials, which broaden the family of amine-stabilized gallium chalcogenides, can be tentatively classified as direct large band gap semiconductors. Their preliminary performance as active material for electrodes in lithium ion batteries has also been tested, demonstrating great potential in energy storage field even without optimization. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01663d

  8. Surfactant-thermal syntheses, structures, and magnetic properties of Mn-Ge-sulfides/selenides

    KAUST Repository

    Zhang, Guodong; Li, Peizhou; Ding, Junfeng; Liu, Yi; Xiong, Weiwei; Nie, Lina; Wu, Tao; Zhao, Yanli; Tok, Alfred Iing Yoong; Zhang, Qichun

    2014-01-01

    tetrahedra, MnGe2Se7 trimer, and MnGe3Se10 T2 cluster. Compounds 1-3 have been fully characterized by single-crystal X-ray diffraction (XRD), powder XRD, UV-vis spectra, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Moreover

  9. Nanoantenna enhanced terahertz spectroscopy of a monolayer of cadmium selenide quantum dots

    KAUST Repository

    Razzari, Luca; Toma, Andrea; Tuccio, Salvatore; Prato, Mirko; De Donato, Francesco; Perucchi, Andrea; Di Pietro, Paola; Marras, Sergio; Liberale, Carlo; Proietti Zaccaria, Remo; De Angelis, Francesco De; Manna, Liberato; Lupi, Stefano; Di Fabrizio, Enzo M.

    2014-01-01

    Exploiting the localization and enhancement capabilities of terahertz resonant dipole nanoantennas coupled through nanogaps, we present an effective method to perform terahertz spectroscopy on an extremely small number of nano-objects.

  10. Active Edge Sites Engineering in Nickel Cobalt Selenide Solid Solutions for Highly Efficient Hydrogen Evolution

    KAUST Repository

    Xia, Chuan

    2017-01-06

    An effective multifaceted strategy is demonstrated to increase active edge site concentration in NiCoSe solid solutions prepared by in situ selenization process of nickel cobalt precursor. The simultaneous control of surface, phase, and morphology result in as-prepared ternary solid solution with extremely high electrochemically active surface area (C = 197 mF cm), suggesting significant exposure of active sites in this ternary compound. Coupled with metallic-like electrical conductivity and lower free energy for atomic hydrogen adsorption in NiCoSe, identified by temperature-dependent conductivities and density functional theory calculations, the authors have achieved unprecedented fast hydrogen evolution kinetics, approaching that of Pt. Specifically, the NiCoSe solid solutions show a low overpotential of 65 mV at -10 mV cm, with onset potential of mere 18 mV, an impressive small Tafel slope of 35 mV dec, and a large exchange current density of 184 μA cm in acidic electrolyte. Further, it is shown that the as-prepared NiCoSe solid solution not only works very well in acidic electrolyte but also delivers exceptional hydrogen evolution reaction (HER) performance in alkaline media. The outstanding HER performance makes this solid solution a promising candidate for mass hydrogen production.

  11. Preparation of EuSe nanoparticles from Eu(III) complex containing selenides

    International Nuclear Information System (INIS)

    Adachi, Taka-aki; Tanaka, Atsushi; Hasegawa, Yasuchika; Kawai, Tsuyoshi

    2008-01-01

    The EuSe nanoparticles were prepared by the thermal reduction of Europium nitrate with new organic selenium compound, tetraphenylphosphonium diphenylphosphinediselenide (PPh 4 )(Se 2 P(C 6 H 5 ) 2 ), for the first time. EuSe nanoparticles were identified by the X-ray diffraction (XRD), the transmission electron microscope (TEM) and the energy dispersive X-ray spectroscopy (EDX) measurements. The average size of the EuSe nanoparticles was found to be 19 nm. The energy gap in EuSe nanoparticles of 19 nm was estimated by edge of absorption band, giving the energy gap of 1.86 eV

  12. Effect of temperature on optical and structural properties of indium selenide thin films

    International Nuclear Information System (INIS)

    Asabe, M.R.; Manikshete, A.H.; Hankare, P.P.

    2013-01-01

    In 2 Se 3 thin film have been prepared for the first time by using a relatively simple chemical bath deposition technique at room temperature using indium chloride, tartaric acid, hydrazine hydrate and sodium selenosulphate in an aqueous alkaline medium. Various preparative conditions of thin film deposition are outlined. The films deposited at optimum preparative parameters are annealed at different temperatures. The as-deposited films those annealed at 100℃ and have been characterized by X-ray diffraction (XRD), Energy Dispersive Analysis by X-ray (EDAX), Optical absorption and scanning electron microscopy (SEM). The as grown films were found to be transparent, uniform, well adherent and brown in color. The XRD analysis of the as-deposited and annealed films shows the presence of polycrystalline nature in tetragonal crystal structure. EDAX study reveals that as-deposited films are almost stoichiometric while optical absorption study shows the presence of band gap for direct while optical absorption study shows the presence of band gap for direct transition at 2.35 and 2.10 eV respectively, for the as-deposited and annealed films. SEM study indicated the presence of uniformly distributed grains over the surface of substrate for the as-deposited as well as annealed film. (author)

  13. Optical studies of 2DEGs in Zinc Selenide quantum wells in high magnetic fields

    International Nuclear Information System (INIS)

    Ossau, Wolfgang J.; Astakhov, G.V.; Yakovlev, D.R.; Crooker, Scott A.; Waag, A.

    2002-01-01

    Optical properties of a two-dimensional electron gas in ZnSe/(Zn,Be,Mg)Se quantum well structures have been examined by means of photoluminescence and reflectivity techniques in external magnetic fields up to 50 T. For these structures the Fermi energy of the two-dimensional electron gas is falling in the range between the trion binding energy and the exciton binding energy, which keeps the dominating role of Coulombic interaction between electrons and photoexcited holes. Characteristic peculiarities of optical spectra are discussed.

  14. Synthesis, structure and electrical properties of a new tin vanadium selenide

    International Nuclear Information System (INIS)

    Atkins, Ryan; Disch, Sabrina; Jones, Zachary; Haeusler, Ines; Grosse, Corinna; Fischer, Saskia F.; Neumann, Wolfgang; Zschack, Paul; Johnson, David C.

    2013-01-01

    The turbostratically disordered misfit layer compound (SnSe) 1.15 VSe 2 was synthesized and structurally characterized. Electrical transport measurements suggest this compound undergoes a charge or spin density wave (CDW or SDW) transition, which has not been observed in previous misfit layer compounds. The (SnSe) 1.15 VSe 2 compound, created through the modulated elemental reactants technique, contains highly oriented intergrowths of SnSe bilayers and VSe 2 structured Se–V–Se trilayers with abrupt interfaces between them perpendicular to the c-axis. X-ray diffraction data and transmission electron microscope images show that each constituent has in-plane crystallinity but that there is a random rotational disorder between the constituent layers. Temperature-dependent electrical resistivity data and Hall measurements are consistent with (SnSe) 1.15 VSe 2 being a metal, however an abrupt increase in the resistivity occurs between 30 and 100 K. The carrier concentration decreases by approximately 1 carrier per vanadium atom during this temperature interval. - Graphical abstract: Turbostratically disordered (SnSe) 1.15 VSe 2 . - Highlights: • New compound (SnSe) 1.15 VSe 2 . • Turbostratic disorder. • Charge density wave at 100 K

  15. Wavelength dependent measurement of extinction in an extended-face crystal of zinc selenide

    International Nuclear Information System (INIS)

    Stevenson, A.W.; Barnea, Z.

    1982-01-01

    The effect of extinction on Bijvoet ratios is demonstrated. It is suggested that an observed anomaly in the wavelength dependence of ZnSe Bijvoet ratios is due to the Borrmann effect. It is shown that wavelength dependent studies of extinction may be used to obtain extinction parameters from relative intensity measurements without resorting to a refined scale factor

  16. Indium selenide (In2Se3) thin film for phase-change memory

    International Nuclear Information System (INIS)

    Lee, Heon; Kang, Dae-Hwan; Tran, Lung

    2005-01-01

    A cross-point type phase-change random access memory (PRAM) device without an access transistor is successfully fabricated with the In 2 Se 3 -phase-change resistor, which has much higher electrical resistivity than Ge 2 Sb 2 Te 5 and of which electric resistivity can be varied by the factor of 10 5 times, related with the degree of crystallization. Due to its higher electrical resistivity, the switching power can be delivered more effectively. Since In 2 Se 3 is single-phase binary compound, the device failure related to phase decomposition can be avoided. Since the volume of phase change is very limited, and the heating duration is only for few tens of nanoseconds to 10 μs, the transition of In 2 Se 3 -phase-change material is done under very far from its thermodynamic equilibrium condition, and thus, formation of the secondary phases or different crystalline phases was not observed. The static mode switching (dc test) is tested for the 5 μm-sized In 2 Se 3 PRAM device. In the first sweep, the as-grown amorphous In 2 Se 3 resistor showed the high resistance state at low voltage region. However, when it reached the threshold voltage, the electrical resistance of the device was drastically reduced through the formation of an electrically conducting path. The pulsed mode switching of the 5 μm-sized In 2 Se 3 PRAM device shows that the reset (crystalline → amorphous) of the device was done with a 70 ns-3.1 V pulse and the set (amorphous → crystalline) of the device was done with a 10 μs-1.2 V pulse. As high as 100 of switching dynamic range (ratio of R high to R low ) was observed

  17. Design and Optimization of Copper Indium Gallium Selenide Thin Film Solar Cells

    Science.gov (United States)

    2015-09-01

    cathode material= Aluminum y.min=0 y.max=$topcontht x.min=$topxcontstart x.max=$topxcontend elec num=2 name= anode bottom 46 # DOPING doping...for this collection of information is estimated to average 1 hour per response, including the time for reviewing instruction, searching existing data...Design ........................................18 C. TRAP DENSITY IN CIGS ALLOYS ....................................................19 III. TCAD

  18. Zinc Cadmium Selenide Cladded Quantum Dot Based Electroluminescent and Nonvolatile Memory Devices

    Science.gov (United States)

    Al-Amody, Fuad H.

    This dissertation presents electroluminescent (EL) and nonvolatile memory devices fabricated using pseudomorphic ZnCdSe-based cladded quantum dots (QDs). These dots were grown using our own in-school built novel reactor. The EL device was fabricated on a substrate of ITO (indium tin oxide) coated glass with the quantum dots sandwiched between anode and cathode contacts with a small barrier layer on top of the QDs. The importance of these cladded dots is to increase the quantum yield of device. This device is unique as they utilize quantum dots that are pseudomorphic (nearly lattice-matched core and the shell of the dot). In the case of floating quantum dot gate nonvolatile memory, cladded ZnCdSe quantum dots are deposited on single crystalline gate insulator (ZnMgS/ZnMgSe), which is grown using metal-organic chemical vapor deposition (MOCVD). The control gate dielectric layer of the nonvolatile memory is Si3N4 or SiO2 and is grown using plasma enhanced chemical vapor deposition (PECVD). The cladded dots are grown using an improved methodology of photo-assisted microwave plasma metal-organic chemical vapor deposition (PMP-MOCVD) enhanced reactor. The cladding composition of the core and shell of the dots was engineered by the help of ultraviolet light which changed the incorporation of zinc (and hence composition of ZnCdSe). This makes ZnxCd1--xSe-ZnyCd1--y Se QDs to have a low composition of zinc in the core than the cladding (x

  19. Room temperature chemical synthesis of lead selenide thin films with preferred orientation

    Science.gov (United States)

    Kale, R. B.; Sartale, S. D.; Ganesan, V.; Lokhande, C. D.; Lin, Yi-Feng; Lu, Shih-Yuan

    2006-11-01

    Room temperature chemical synthesis of PbSe thin films was carried out from aqueous ammoniacal solution using Pb(CH3COO)2 as Pb2+ and Na2SeSO3 as Se2- ion sources. The films were characterized by a various techniques including, X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HR-TEM), selected area electron diffraction (SAED), Fast Fourier transform (FFT) and UV-vis-NIR techniques. The study revealed that the PbSe thin film consists of preferentially oriented nanocubes with energy band gap of 0.5 eV.

  20. Room temperature chemical synthesis of lead selenide thin films with preferred orientation

    Energy Technology Data Exchange (ETDEWEB)

    Kale, R.B. [Department of Chemical Engineering, National Tsing-Hua University, Hsin-Chu, Taiwan 30043 (China)]. E-mail: rb_kale@yahoo.co.in; Sartale, S.D. [Hahn Meitner Institute, Glienicker Strasse-100, D-14109 Berlin (Germany); Ganesan, V. [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452017 (India); Lokhande, C.D. [Thin Film Physics Laboratory, Department of Physics, Shivaji University, Kolhapur 416004 (India); Lin, Y.-F. [Department of Chemical Engineering, National Tsing-Hua University, Hsin-Chu, Taiwan 30043 (China); Lu, S.-Y. [Department of Chemical Engineering, National Tsing-Hua University, Hsin-Chu, Taiwan 30043 (China)]. E-mail: sylu@mx.nthu.edu.tw

    2006-11-15

    Room temperature chemical synthesis of PbSe thin films was carried out from aqueous ammoniacal solution using Pb(CH{sub 3}COO){sub 2} as Pb{sup 2+} and Na{sub 2}SeSO{sub 3} as Se{sup 2-} ion sources. The films were characterized by a various techniques including, X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HR-TEM), selected area electron diffraction (SAED), Fast Fourier transform (FFT) and UV-vis-NIR techniques. The study revealed that the PbSe thin film consists of preferentially oriented nanocubes with energy band gap of 0.5 eV.

  1. Observation of point defects in impurity-doped zinc selenide films using a monoenergetic positron beam

    International Nuclear Information System (INIS)

    Miyajima, T.; Okuyama, H.; Akimoto, K.; Mori, Y.; Wei, L.; Tanigawa, S.

    1992-01-01

    We studied point defects in ZnSe films grown by molecular beam epitaxy using the positron annihilation method. We found that doping with Ga atoms induces vacancy-type defects such as Zn vacancies, and that heavy doping with oxygen atoms induces interstitial type defects. We think that these defects are one of the causes of active carrier saturation in doped ZnSe films. (author)

  2. Synthesis and characterization of Fe doped cadmium selenide thin films by spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Abhijit A., E-mail: aay_physics@yahoo.co.in [Thin Film Physics Laboratory, Department of Physics, Electronics and Photonics, Rajarshi Shahu Mahavidyalaya, Latur 413 512, Maharashtra (India)

    2012-12-05

    Highlights: Black-Right-Pointing-Pointer Simple and inexpensive method to dope trivalent Fe in CdSe thin films. Black-Right-Pointing-Pointer Fe doped CdSe thin films are highly photosensitive. Black-Right-Pointing-Pointer AFM analysis shows uniform deposition of film over the entire substrate surface. Black-Right-Pointing-Pointer The band gap energy decreases from 1.74 to 1.65 eV with Fe doping. Black-Right-Pointing-Pointer Film resistivity decreases to 6.76 Multiplication-Sign 10{sup 4} {Omega}-cm with Fe doping in CdSe thin films. - Abstract: Undoped and Fe doped CdSe thin films have been deposited onto the amorphous and fluorine doped tin oxide coated glass substrates by spray pyrolysis. The Fe doping concentration has been optimized by photoelectrochemical (PEC) characterization technique. The structural, surface morphological, compositional, optical and electrical properties of undoped and Fe doped CdSe thin films have been studied. X-ray diffraction study reveals that the as deposited CdSe films possess hexagonal crystal structure with preferential orientation along (1 0 0) plane. AFM analysis shows uniform deposition of the film over the entire substrate surface with minimum surface roughness of 7.90 nm. Direct allowed type of transition with band gap decreasing from 1.74 to 1.65 eV with Fe doping has been observed. The activation energy of the films has been found to be in the range of 0.14-0.19 eV at low temperature and 0.27-0.44 eV at high temperature. Semi-conducting behavior has been observed from resistivity measurements. The thermoelectric power measurements reveal that the films are of n type.

  3. Change in the Magnetocapacity in the Paramagnetic Region in a Cation-Substituted Manganese Selenide

    Science.gov (United States)

    Aplesnin, S. S.; Sitnikov, M. N.; Zhivul'ko, A. M.

    2018-04-01

    The capacity and the dielectric loss tangent of a Gd x Mn1- x Se ( x ≤ 0.2) solid solution have been measured in the frequency range 1-300 kHz without a magnetic field and in a magnetic field of 8 kOe in the temperature range 100-450 K, and the magnetic moment of the solid solution has been measured in a field of 8.6 kOe. The magnetocapacity effect and the change in the magnetocapacity sign have been observed in room temperature in the paramagnetic region. A correlation of the changes in the dielectric permittivity and the magnetic susceptibility with temperature has been revealed. The magnetocapacity is described using the model with orbital electron ordering and the Maxwell-Wagner model.

  4. Synthesis and characterization of rare-earth oxide transition-metal arsenides and selenides

    International Nuclear Information System (INIS)

    Peschke, Simon Friedrich

    2017-01-01

    The present thesis includes two different quaternary systems that have been studied extensively. On the one hand, several samples of the REFeAsO_1_-_xF_x family of iron-based superconductors were prepared using a novel solid state metathesis reaction, which also provided a possibility to prepare late rare-earth compounds of this family at ambient pressure. Comparison of structural and physical properties of those samples with samples from conventional solid state and high pressure syntheses revealed both, commonalities as well as striking differences. The observations gave reason to the conclusion that superconducting properties strongly depend, beside electronic infl uence, on the structural parameters. On the other hand, the quaternary system RE-T-Se-O with T = Ti-Mn was investigated using a NaI/KI flux mediated synthesis route. It has been shown that oC -La_2O_2MnSe_2 is exclusively accessible in su fficient purity by the use of a fl ux material. Therefore, further syntheses in this quaternary system were performed by a flux mediated synthesis route leading to a large amount of new materials. Among them, a new polymorph mC-La_2O_2MnSe_2 which forms, together with La_4MnSe_3O_4 and La_6MnSe_4O_6, the series La_2_n_+_2MnSe_n_+_2O_2_n_+_2. In addition, the alternative preparation method also enabled a large scale synthesis of the first examples of rare-earth chromium oxyselenides with chromium in the oxidation state +II, namely RE_2CrSe_2O_2 (RE = La-Nd), which opened the door to study their magnetism in detail by powder neutron diffraction and muon spin rotation techniques. Research into the La-V-Se-O system revealed the first fi ve quaternary compounds of this family with interesting magnetic properties including ferromagnetism, antiferromagnetism, metamagnetism and more complex behaviour. In addition, the crystal structure of two new quaternary titanium containing oxyselenides were identifi ed and revealed unique structural building blocks that have not been observed in these systems before. The results of this thesis demonstrate not only the power of alternative preparation methods, but also the still increasing structural variety in the discussed quaternary systems. Strategic research in the field of transition-metal oxypnictides and oxychalcogenides, which still include a multiplicity of unknown materials, revealed numerous compounds with interesting physical properties and further investigations will probably uncover also new superconducting materials.

  5. Conversion of visible light to electrical energy - Stable cadmium selenide photoelectrodes in aqueous electrolytes

    Science.gov (United States)

    Wrighton, M. S.; Ellis, A. B.; Kaiser, S. W.

    1977-01-01

    Stabilization of n-type CdSe to photoanodic dissolution is reported. The stabilization is accomplished by the competitive oxidation of S(--) or S(n)(--) at the CdSe photoanode in an electrochemical cell. Such stabilized cells are shown to sustain the conversion of low energy (not less than 1.7 eV) visible light to electricity with good efficiency and no deterioration of the CdSe photoelectrode or of the electrolyte. The electrolyte undergoes no net chemical change because the oxidation occurring at the photoelectrode is reversed at the cathode. Conversion of monochromatic light at 633 nm to electricity is shown to be up to approximately 9% efficient with output potentials of approximately 0.4 V. Conversion of solar energy to electricity is estimated to be approximately 2% efficient.

  6. Active Edge Sites Engineering in Nickel Cobalt Selenide Solid Solutions for Highly Efficient Hydrogen Evolution

    KAUST Repository

    Xia, Chuan; Liang, Hanfeng; Zhu, Jiajie; Schwingenschlö gl, Udo; Alshareef, Husam N.

    2017-01-01

    free energy for atomic hydrogen adsorption in NiCoSe, identified by temperature-dependent conductivities and density functional theory calculations, the authors have achieved unprecedented fast hydrogen evolution kinetics, approaching that of Pt

  7. Understanding sensitization behavior of lead selenide photoconductive detectors by charge separation model

    International Nuclear Information System (INIS)

    Zhao, Lihua; Qiu, Jijun; Weng, Binbin; Chang, Caleb; Yuan, Zijian; Shi, Zhisheng

    2014-01-01

    We introduce a charge separation model in this work to explain the mechanism of enhanced photoconductivity of polycrystalline lead salt photoconductors. Our results show that this model could clarify the heuristic fabrication processes of such lead salt detectors that were not well understood and often considered mysterious for nearly a century. The improved lifetime and performance of the device, e.g., responsivity, are attributed to the spatial separation of holes and electrons, hence less possibility of carrier recombination. This model shows that in addition to crystal quality the size of crystallites, the depth of outer conversion layer, and doping concentration could all affect detector performance. The simulation results agree well with experimental results and thus offer a very useful tool for further improvement of lead salt detectors. The model was developed with lead salt family of photoconductors in mind, but may well be applicable to a wider class of semiconducting films

  8. Rational Design of Cobalt-Iron Selenides for Highly Efficient Electrochemical Water Oxidation.

    Science.gov (United States)

    Zhang, Jun-Ye; Lv, Lin; Tian, Yifan; Li, Zhishan; Ao, Xiang; Lan, Yucheng; Jiang, Jianjun; Wang, Chundong

    2017-10-04

    Exploring active, stable, earth-abundant, low-cost, and high-efficiency electrocatalysts is highly desired for large-scale industrial applications toward the low-carbon economy. In this study, we apply a versatile selenizing technology to synthesize Se-enriched Co 1-x Fe x Se 2 catalysts on nickel foams for oxygen evolution reactions (OERs) and disclose the relationship between the electronic structures of Co 1-x Fe x Se 2 (via regulating the atom ratio of Co/Fe) and their OER performance. Owing to the fact that the electron configuration of the Co 1-x Fe x Se 2 compounds can be tuned by the incorporated Fe species (electron transfer and lattice distortion), the catalytic activity can be adjusted according to the Co/Fe ratios in the catalyst. Moreover, the morphology of Co 1-x Fe x Se 2 is also verified to strongly depend on the Co/Fe ratios, and the thinner Co 0.4 Fe 0.6 Se 2 nanosheets are obtained upon selenization treatment, in which it allows more active sites to be exposed to the electrolyte, in turn promoting the OER performance. The Co 0.4 Fe 0.6 Se 2 nanosheets not only exhibit superior OER performance with a low overpotential of 217 mV at 10 mA cm -2 and a small Tafel slope of 41 mV dec -1 but also possess ultrahigh durability with a dinky degeneration of 4.4% even after 72 h fierce water oxidation test in alkaline solution, which outperforms the commercial RuO 2 catalyst. As expected, the Co 0.4 Fe 0.6 Se 2 nanosheets have shown great prospects for practical applications toward water oxidation.

  9. Room temperature chemical synthesis of lead selenide thin films with preferred orientation

    International Nuclear Information System (INIS)

    Kale, R.B.; Sartale, S.D.; Ganesan, V.; Lokhande, C.D.; Lin, Y.-F.; Lu, S.-Y.

    2006-01-01

    Room temperature chemical synthesis of PbSe thin films was carried out from aqueous ammoniacal solution using Pb(CH 3 COO) 2 as Pb 2+ and Na 2 SeSO 3 as Se 2- ion sources. The films were characterized by a various techniques including, X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HR-TEM), selected area electron diffraction (SAED), Fast Fourier transform (FFT) and UV-vis-NIR techniques. The study revealed that the PbSe thin film consists of preferentially oriented nanocubes with energy band gap of 0.5 eV

  10. Ozone Oxidation of Self-Assembled Monolayers on SiOx-Coated Zinc Selenide Surfaces

    Science.gov (United States)

    McIntire, T. M.; Ryder, O. S.; Finlayson-Pitts, B. J.

    2008-12-01

    Airborne particles are important for visibility, human health, climate, and atmospheric reactions. Atmospheric particles contain a significant fraction of organics and such compounds present on airborne particles are susceptible to oxidation by atmospheric oxidants, such as OH, ozone, halogen atoms, and nitrogen trioxide. Oxidized organics associated with airborne particles are thought to be polar, hygroscopic species with enhanced cloud-nucleating properties. Oxide layers on silicon, or SiO2-coated substrates, act as models of environmentally relevant surfaces such as dust particles upon which organics adsorb. We have shown previously that ozone oxidation of unsaturated self-assembled monolayers (SAMs) on silicon attenuated total reflectance (ATR) crystals leads to the formation of carbonyl groups and micron-sized, hydrophobic organic aggregates surrounded by carbon depleted substrate that do not have increased water uptake as previously assumed. Reported here are further ATR-FTIR studies of the oxidation of alkene SAMs on ZnSe and SiO2-coated ZnSe. These substrates have the advantage that they transmit below 1500 cm-1, allowing detection of additional product species. These experiments show that the loss of C=C and formation of carbonyl groups is also accompanied by formation of a peak at 1110 cm-1, attributed to the secondary ozonide. Details concerning the products and mechanism of ozonolysis of alkene SAMs on surfaces based on these new data are presented and the implications for the oxidation of alkenes on airborne dust particles are discussed.

  11. Surfactant-thermal syntheses, structures, and magnetic properties of Mn-Ge-sulfides/selenides

    KAUST Repository

    Zhang, Guodong

    2014-10-06

    Although either surfactants or amines have been investigated to direct the crystal growth of metal chalcogenides, the synergic effect of organic amines and surfactants to control the crystal growth has not been explored. In this report, several organic bases (hydrazine monohydrate, ethylenediamine (en), 1,2-propanediamine (1,2-dap), and 1,3-propanediamine (1,3-dap)) have been employed as structure-directing agents (SDAs) to prepare four novel chalcogenides (Mn3Ge2S7(NH3)4 (1), [Mn(en)2(H2O)][Mn(en)2MnGe3Se9] (2), (1,2-dapH)2{[Mn(1,2-dap)2]Ge2Se7} (3), and (1,3-dapH)(puH)MnGeSe4(4) (pu = propyleneurea) under surfactant media (PEG-400). These as-prepared new crystalline materials provide diverse metal coordination geometries, including MnS3N tetrahedra, MnGe2Se7 trimer, and MnGe3Se10 T2 cluster. Compounds 1-3 have been fully characterized by single-crystal X-ray diffraction (XRD), powder XRD, UV-vis spectra, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Moreover, magnetic measurements for compound 1 showed an obvious antiferromagnetic transition at ∼9 K. Our research not only enriches the structural chemistry of the transitional-metal/14/16 chalcogenides but also allows us to better understand the synergic effect of organic amines and surfactants on the crystallization of metal chalcogenides.

  12. A novel fluorescent array for mercury (II) ion in aqueous solution with functionalized cadmium selenide nanoclusters

    International Nuclear Information System (INIS)

    Chen Jinlong; Gao Yingchun; Xu, ZhiBing; Wu, GenHua; Chen, YouCun; Zhu, ChangQing

    2006-01-01

    Mono-disperse CdSe nanoclusters have been prepared facilely and functionalized with L-cysteine through two steps by using safe and low cost substances. They are water-soluble and biocompatible. Especially these functionalized quantum dots can be stably soluble in water more than for 30 days, and the intensity of fluorescence and absorbance was decreased less than 15% of fresh prepared CdSe colloids. These functionalized CdSe QDs exhibited strong specific affinity for mercury (II) through QDs interface functional groups. Based on the quenching of fluorescence signals of functionalized CdSe QDs at 530 nm and no obvious wavelength shift or no new emission band in present of Hg (II) at pH 7.75 of phosphate buffer solution, a simple, rapid and specific array for Hg (II) was proposed. In comparison with conventional organic fluorophores, these nanoparticles are brighter, more stable against photobleaching, and do not suffer from blinking. Under optimum conditions, the response of linearly proportional to the concentration of Hg (II) between 0 and 2.0 x 10 -6 mol L -1 , and the limit of detection is 6.0 x 10 -9 mol L -1 . The relative standard deviation of six replicate measurements is 1.8% for 1.0 x 10 -7 mol L -1 Hg (II). The mechanism of reaction is also discussed. The proposed method was successfully applied for Hg (II) detection in four real samples with a satisfactory result that was obtained by cold vapor atomic fluorescence spectrometry (CV-AFS)

  13. Selenide isotope generator for the Galileo Mission: SIG/Galileo hermetic receptable test program final report

    International Nuclear Information System (INIS)

    Roedel, S.

    1979-06-01

    The purpose of the receptacle test program was to test various types of hermetically sealed electrical receptacles and to select one model as the spaceflight hardware item for SIG/Galileo thermoelectric generators. The design goal of the program was to qualify a hermetic seal integrity of less than or equal to 1 x 10 -9 std cc He/sec -atm at 400 0 F (204 0 C) and verify a reliability of 0.95 at a 50% confidence level for a flight mission in excess of 7 years

  14. Selenide isotope generator for the Galileo Mission. Axially-grooved heat pipe: accelerated life test results

    International Nuclear Information System (INIS)

    1979-08-01

    The results through SIG/Galileo contract close-out of accelerated life testing performed from June 1978 to June 1979 on axially-grooved, copper/water heat pipes are presented. The primary objective of the test was to determine the expected lifetime of axially-grooved copper/water heat pipes. The heat pipe failure rate, due to either a leak or a build-up of non-condensible gas, was determined. The secondary objective of the test was to determine the effects of time and temperature on the thermal performance parameters relevant to long-term (> 50,000 h) operation on a space power generator. The results showed that the gas generation rate appears to be constant with time after an initial sharp rise although there are indications that it drops to approximately zero beyond approx. 2000 h. During the life test, the following pipe-hours were accumulated: 159,000 at 125 0 C, 54,000 at 165 0 C, 48,000 at 185 0 C, and 8500 at 225 0 C. Heated hours per pipe ranged from 1000 to 7500 with an average of 4720. Applying calculated acceleration factors yields the equivalent of 930,000 pipe-h at 125 0 C. Including the accelerated hours on vendor tested pipes raises this number to 1,430,000 pipe-hours at 125 0 C. It was concluded that, for a heat pipe temperature of 125 0 C and a mission time of 50,000 h, the demonstrated heat pipe reliability is between 80% (based on 159,000 actual pipe-h at 125 0 C) and 98% (based on 1,430,000 accelerated pipe-h at 125 0 C). Measurements indicate some degradation of heat transfer with time, but no detectable degradation of heat transport

  15. Electronic structure of germanium selenide investigated using ultra-violet photo-electron spectroscopy

    International Nuclear Information System (INIS)

    Mishra, P; Lohani, H; Sekhar, B R; Kundu, A K; Menon, Krishnakumar S R; Patel, R; Solanki, G K

    2015-01-01

    The valence band electronic structure of GeSe single crystals has been investigated using angle resolved photoemission spectroscopy (ARPES) and x-ray photoelectron spectroscopy. The experimentally observed bands from ARPES, match qualitatively with our LDA-based band structure calculations along the Γ–Z, Γ–Y and Γ–T symmetry directions. The valence band maximum occurs nearly midway along the Γ–Z direction, at a binding energy of −0.5 eV, substantiating the indirect band gap of GeSe. Non-dispersive features associated with surface states and indirect transitions have been observed. The difference in hybridization of Se and Ge 4p orbitals leads to the variation of dispersion along the three symmetry directions. The predominance of the Se 4p z orbitals, evidenced from theoretical calculations, may be the cause for highly dispersive bands along the Γ–T direction. Detailed electronic structure analysis reveals the significance of the cation–anion 4p orbitals hybridization in the valence band dispersion of IV–VI semiconductors. This is the first comprehensive report of the electronic structure of a GeSe single crystal using ARPES in conjugation with theoretical band structure analysis. (paper)

  16. Hydrozirconation of lithium alkynylselenolate anions. Generation and reactions of alpha-zirconated vinyl selenide intermediates

    Science.gov (United States)

    Dabdoub; Begnini; Guerrero; Baroni

    2000-01-14

    Lithium alkynylselenolate anions react completely with 1.0 equiv of Cp(2)Zr(H)Cl in THF at room temperature to give exclusively the alpha-zirconated vinylselenolate intermediates 23-27, which by treatment with an alkyl halide afforded the alpha-zirconated vinyl alkylselenide intermediates 29-33. Reaction of 29-33 with butyltellurenyl bromide results in the formation of ketene telluro(seleno) acetals 35-39 with total control of the regio- and stereochemistry. The synthetic utility of the ketene telluro(seleno) acetals obtained here was demonstrated by reaction of 36 with butyllithium. This promotes the exclusive and stereospecific removal of the tellurium moiety and enables formation of the corresponding selenium-containing allylic alcohol of type 44, alpha-(alkylseleno)-alpha,beta-unsaturated aldehyde 45, ester 46, or carboxylic acid 47, after reaction with different types of electrophiles.

  17. Solid-state reactions to synthesize nanostructured lead selenide semiconductor powders by high-energy milling

    Energy Technology Data Exchange (ETDEWEB)

    Rojas-Chavez, H., E-mail: uu_gg_oo@yahoo.com.mx [Centro de Investigacion e Innovacion Tecnologica - IPN, Cerrada de CECATI s/n, Col. Santa Catarina, Del. Azcapotzalco (Mexico) and Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada - IPN, Legaria 694, Col. Irrigacion, Del. Miguel Hidalgo (Mexico); Reyes-Carmona, F. [Facultad de Quimica - UNAM, Circuito de la Investigacion Cientifica s/n, C.U. Del. Coyoacan (Mexico); Jaramillo-Vigueras, D. [Centro de Investigacion e Innovacion Tecnologica - IPN, Cerrada de CECATI s/n, Col. Santa Catarina, Del. Azcapotzalco (Mexico)

    2011-10-15

    Highlights: {yields} PbSe synthesized from PbO instead of Pb powder do not require an inert atmosphere. {yields} During high-energy milling oxygen has to be chemically reduced from the lead oxide. {yields} Solid-state and solid-gas chemical reactions promote both solid and gaseous products. -- Abstract: Both solid-solid and gas-solid reactions have been traced during high-energy milling of Se and PbO powders under vial (P, T) conditions in order to synthesize the PbSe phase. Chemical and thermodynamic arguments are postulated to discern the high-energy milling mechanism to transform PbO-Se micropowders onto PbSe-nanocrystals. A set of reactions were evaluated at around room temperature. Therefore an experimental campaign was designed to test the nature of reactions in the PbO-Se system during high-energy milling.

  18. Solid-state reactions to synthesize nanostructured lead selenide semiconductor powders by high-energy milling

    International Nuclear Information System (INIS)

    Rojas-Chavez, H.; Reyes-Carmona, F.; Jaramillo-Vigueras, D.

    2011-01-01

    Highlights: → PbSe synthesized from PbO instead of Pb powder do not require an inert atmosphere. → During high-energy milling oxygen has to be chemically reduced from the lead oxide. → Solid-state and solid-gas chemical reactions promote both solid and gaseous products. -- Abstract: Both solid-solid and gas-solid reactions have been traced during high-energy milling of Se and PbO powders under vial (P, T) conditions in order to synthesize the PbSe phase. Chemical and thermodynamic arguments are postulated to discern the high-energy milling mechanism to transform PbO-Se micropowders onto PbSe-nanocrystals. A set of reactions were evaluated at around room temperature. Therefore an experimental campaign was designed to test the nature of reactions in the PbO-Se system during high-energy milling.

  19. Crystal quality of two-dimensional gallium telluride and gallium selenide using Raman fingerprint

    Directory of Open Access Journals (Sweden)

    Jannatul Susoma

    2017-01-01

    Full Text Available We have established Raman fingerprint of GaTe and GaSe to investigate their crystal quality. As unencapsulated, they both oxidise in ambient conditions which can be detected in their Raman analysis. X-ray photoelectron spectroscopy (XPS analysis shows a good agreement with Raman analysis. 50-nm-thick Al2O3 encapsulation layer deposited by atomic layer deposition (ALD inhibits degradation in ambient conditions.

  20. Antiferroquadrupolar ordering and anisotropic magnetic phase diagram of dysprosium palladium bronze, DyPd3S4

    International Nuclear Information System (INIS)

    Matsuoka, Eiichi; Tayama, Takashi; Sakakibara, Toshiro; Hiroi, Zenji; Takeda, Naoya; Ishikawa, Masayasu; Shirakawa, Naoki

    2007-01-01

    From the measurements of magnetization and specific heat, we constructed B-T phase diagrams of single-crystalline DyPd 3 S 4 which is known to exhibit antiferroquadrupolar (AFQ) and antiferromagnetic (AFM) ordering at low temperatures. The phase diagrams are found to be highly anisotropic and re-entrant, which are typical of rare-earth compounds exhibiting multipolar ordering. The crystalline electric field (CEF) scheme of Dy 3+ in DyPd 3S4 was deduced from the specific heat and magnetization measurements of the Y-diluted compounds Dy 1-x Y x Pd 3 S 4 (0.1≤x≤0.9) and discussed in detail. The CEF ground state was determined to be the orbitally-degenerated quartet Γ 67 (1) , and the overall splitting width was estimated to be about 104 K. No correlation was found between the anisotropy of T Q and that of the Zeeman splitting width of the ground quartet Γ 67 (1) . (author)

  1. Effect of Ligand Field Tuning on the SMM Behavior for Three Related Alkoxide-Bridged Dysprosium Dimers.

    Science.gov (United States)

    Peng, Yan; Mereacre, Valeriu; Baniodeh, Amer; Lan, Yanhua; Schlageter, Martin; Kostakis, George E; Powell, Annie K

    2016-01-04

    The synthesis and characterization of three Dy2 compounds, [Dy2(HL1)2(NO3)4] (1), [Dy2(L2)2(NO3)4] (2), and [Dy2(HL3)2(NO3)4] (3), formed using related tripodal ligands with a central tertiary amine bearing picolyl and alkoxy arms, 2-[(2-hydroxy-ethyl)-pyridin-2-ylmethylamino]-ethanol (H2L1), 2-(bis-pyridin-2-ylmethylamino)-ethanol (HL2), and 2-(bis-pyridin-2-ylmethylamino)-propane-1,3-diol (H2L3), are reported. The compounds are rare examples of alkoxide-bridged {Dy2} complexes and display capped square antiprism coordination geometry around each Dy(III) ion. Changes in the ligand field environment around the Dy(III) ions brought about through variations in the ligand donors can be gauged from the magnetic properties, with compounds 1 and 2 showing antiparallel coupling between the Dy(III) ions and 3 showing parallel coupling. Furthermore, slow relaxation of the magnetization typical of SMM behavior could be observed for compounds 2 and 3, suggesting that small variations in the ligand field can have a significant influence on the slow relaxation processes responsible for SMM behavior of Dy(III)-based systems.

  2. Effects of magnetic annealing on structure and multiferroic properties of pure and dysprosium substituted BiFeO 3

    KAUST Repository

    Zhang, Shuxia; Yao, Yingbang; Chen, Yao; Wang, Dongliang; Zhang, Xianping; Awaji, Satoshi; Watanabe, Kazuo; Ma, Yanwei

    2012-01-01

    In this work, the effects of magnetic annealing on crystal structure and multiferroic properties of BiFeO 3 and Bi 0.85Dy 0.15FeO 3 have been investigated. It is found that the X-ray diffraction patterns of pure BiFeO 3 samples are obviously broadened after magnetic annealing, whereas those of Bi 0.85Dy 0.15FeO 3 samples are almost unchanged. Magnetic field annealing did not affect the magnetic properties of these two kinds of samples much. However, ferroelectric properties of the two materials exhibited different behaviors after magnetic field annealing. For pure BiFeO 3 samples, the remnant polarizations (P r) are suppressed; in contrast, for Bi 0.85Dy 0.15FeO 3 samples, P r is greatly enhanced. Possible mechanisms for the effects of magnetic field annealing have been discussed. © 2012 Elsevier B.V. All rights reserved.

  3. A rational approach to the modulation of the dynamics of the magnetisation in a dysprosium-nitronyl-nitroxide radical complex.

    Science.gov (United States)

    Poneti, Giordano; Bernot, Kevin; Bogani, Lapo; Caneschi, Andrea; Sessoli, Roberta; Wernsdorfer, Wolfgang; Gatteschi, Dante

    2007-05-14

    A control of the dynamics of the magnetisation is chemically achieved in a ring-like Dy-radical based molecule, allowing the estimation of the quantum tunneling frequency with a (4)He-cooled susceptometer.

  4. Manufacturing of Dysprosium-Iron Alloys by Electrolysis in Fluoride-Based Electrolytes. Electrolysis in a Laboratory-Scale Cell

    Science.gov (United States)

    Martinez, Ana Maria; Osen, Karen Sende; Støre, Anne; Gudbrandsen, Henrik; Kjos, Ole Sigmund; Solheim, Asbjørn; Wang, Zhaohui; Oury, Alexandre; Namy, Patrick

    2018-04-01

    Electrolytic production of light rare earth elements and rare earth alloys with transition elements takes place in a fluoride-based electrolyte using rare earth oxides as raw material. The optimization of this method, mainly in terms of the energy efficiency and environmental impact control, is rather challenging. Anode effects, evolution of fluorine-containing compounds and side cathode reactions could largely be minimized by good control of the amount of rare earth oxide species dissolved in the fluoride-based electrolyte and their dissolution rate. The Dy2O3 feed rate needed for stable cell operation was studied by following up the anode voltage and gas analysis. On-line analysis of the cell off-gases by FTIR showed that the electrochemical reaction for the formation of Dy-Fe alloy gives mainly CO gas and that CF4 is starting to evolve gradually at anode voltages of ca. 3.25 V. The limiting current density for the discharge of the oxide ions at the graphite anode was in the range of 0.1 to 0.18 A cm-2 at dissolved Dy2O3 contents of ca. 1 wt pct. Modeling of the laboratory cell reactor was also carried out by implementing two models, i.e., an electrical model simulating the current density distribution at the electrodes and a laminal bubbly flow model that explains the electrolyte velocity induced by gas bubble production at the anode.

  5. Sol-gel synthesis and crystallization kinetics of dysprosium-titanate Dy2Ti2O7 for photonic applications

    Czech Academy of Sciences Publication Activity Database

    Mrázek, Jan; Potel, M.; Buršík, Jiří; Mráček, A.; Kallistová, Anna; Jonášová, Šárka; Boháček, Jan; Kašík, Ivan

    2015-01-01

    Roč. 168, November (2015), s. 159-167 ISSN 0254-0584 Institutional support: RVO:67985882 ; RVO:68081723 ; RVO:67985831 Keywords : Ceramics * Inorganic compounds * Optical materials Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering; JG - Metallurgy (UFM-A); CB - Analytical Chemistry, Separation (GLU-S) Impact factor: 2.101, year: 2015

  6. Critical Rare Earths, National Security, and U.S.-China Interactions: A Portfolio Approach to Dysprosium Policy Design

    Science.gov (United States)

    2015-01-01

    from Donald and Susan Rice , both funds which enabled me to focus on the dissertation. I thank Dean Susan Marquis for her dedication to the growth of...quota of 89,2000 tonnes (Table 2.2). The sprawling black market not only prevents Beijing’s efforts to bring the production under its levers to...yttrium are often used for pigmentation for consumer products such as paint and sunglasses. REE-based lasers are used for cosmetic , epidermal, and

  7. White- and blue-light-emitting dysprosium(III) and terbium(III)-doped gadolinium titanate phosphors.

    Science.gov (United States)

    Antić, Ž; Kuzman, S; Đorđević, V; Dramićanin, M D; Thundat, T

    2017-06-01

    Here we report the synthesis and structural, morphological, and photoluminescence analysis of white- and blue-light-emitting Dy 3 + - and Tm 3 + -doped Gd 2 Ti 2 O 7 nanophosphors. Single-phase cubic Gd 2 Ti 2 O 7 nanopowders consist of compact, dense aggregates of nanoparticles with an average size of ~25 nm for Dy 3 + -doped and ~50 nm for Tm 3 + -doped samples. The photoluminescence results indicated that ultraviolet (UV) light excitation of the Dy 3 + -doped sample resulted in direct generation of white light, while a dominant yellow emission was obtained under blue-light excitation. Intense blue light was obtained for Tm 3 + -doped Gd 2 Ti 2 O 7 under UV excitation suggesting that this material could be used as a blue phosphor. Copyright © 2016 John Wiley & Sons, Ltd.

  8. Isothermal sections of phase equilibria diagrams for systems (terbium, dysprosium, holmium)-molybdenum-boron at 1273 K

    International Nuclear Information System (INIS)

    Kuz'ma, Yu.B.; Zakharchuk, N.P.; Maksimova, L.T.

    1988-01-01

    The methods of X-ray analysis are used to study the R-Mo-B (R-Tb, Dy, Ho) systems and isothermal sections of phase equilibria diagrams at 1273 K are plotted. A formation of RMoB 4 (structure of the YCrB 4 type) is confirmed and borides R 3 MoB 7 (structure of the Er 3 CrB 7 type) and ∼ RMo 4 B 8 (of the unknown structure) are obtained for the first time. Borides DyMoB 3 and HoMoB 3 are of the ErMoB 3 structure. Lattice periods of new compounds are indicated. Diffractogrammes of borides Dy 3 MoB 7 and DyMoB 3 are calculated. A peculiarity of components interaction in the systems rare-earth metal-molybdenum-boron is considered

  9. Effects of magnetic annealing on structure and multiferroic properties of pure and dysprosium substituted BiFeO 3

    KAUST Repository

    Zhang, Shuxia

    2012-07-01

    In this work, the effects of magnetic annealing on crystal structure and multiferroic properties of BiFeO 3 and Bi 0.85Dy 0.15FeO 3 have been investigated. It is found that the X-ray diffraction patterns of pure BiFeO 3 samples are obviously broadened after magnetic annealing, whereas those of Bi 0.85Dy 0.15FeO 3 samples are almost unchanged. Magnetic field annealing did not affect the magnetic properties of these two kinds of samples much. However, ferroelectric properties of the two materials exhibited different behaviors after magnetic field annealing. For pure BiFeO 3 samples, the remnant polarizations (P r) are suppressed; in contrast, for Bi 0.85Dy 0.15FeO 3 samples, P r is greatly enhanced. Possible mechanisms for the effects of magnetic field annealing have been discussed. © 2012 Elsevier B.V. All rights reserved.

  10. Generation of White Light from Dysprosium-Doped Strontium Aluminate Phosphor by a Solid-State Reaction Method

    Science.gov (United States)

    Sahu, Ishwar Prasad; Bisen, D. P.; Brahme, N.; Tamrakar, Raunak Kumar

    2016-04-01

    A single-host lattice, white light-emitting SrAl2O4:Dy3+ phosphor was synthesized by a solid-state reaction method. The crystal structure of prepared SrAl2O4:Dy3+ phosphor was in a monoclinic phase with space group P21. The chemical composition of the sintered SrAl2O4:Dy3+ phosphor was confirmed by the energy dispersive x-ray spectroscopy technique. Under ultra-violet excitation, the characteristic emissions of Dy3+ are peaking at 475 nm, 573 nm and 660 nm, originating from the transitions of 4F9/2 → 6H15/2, 4F9/2 →&!nbsp; 6H13/2 and 4F9/2 → 6H11/2 in the 4f9 configuration of Dy3+ ions. Commission International de I'Eclairage color coordinates of SrAl2O4:Dy3+ are suitable for white light-emitting phosphor. In order to investigate the suitability of the samples as white color light sources for industrial uses, correlated color temperature (CCT) and color rendering index (CRI) values were calculated. Values of CCT and CRI were found well within the defined acceptable range. Mechanoluminescence (ML) intensity of SrAl2O4:Dy3+ phosphor increased linearly with increasing impact velocity of the moving piston. Thus, the present investigation indicates piezo-electricity was responsible for producing ML in sintered SrAl2O4:Dy3+ phosphor. Decay rates of the exponential decaying period of the ML curves do not change significantly with impact velocity. The photoluminescence and ML results suggest that the synthesized SrAl2O4:Dy3+ phosphor was useful for the white light-emitting diodes and stress sensor respectively.

  11. Complexes of lanthanum(III), cerium(III), samarium(III) and dysprosium(III) with substituted piperidines

    Energy Technology Data Exchange (ETDEWEB)

    Manhas, B S; Trikha, A K; Singh, H; Chander, M

    1983-11-01

    Complexes of the general formulae M/sub 2/Cl/sub 6/(L)/sub 3/.C/sub 2/H/sub 5/OH and M/sub 2/(NO/sub 3/)/sub 6/(L)/sub 2/.CH/sub 3/OH have been synthesised by the reactions of chlorides and nitrates of La(III), Ce(III), Sm(III) and Dy(III) with 2-methylpiperidine, 3-methylpiperidine and 4-methylpiperidine. These complexes have been characterised on the basis of their elemental analysis, and IR and electronic reflectance spectra. IR spectral data indicate the presence of coordinated ethanol and methanol molecules and bidentate nitrate groups. Coordination numbers of the metal ions vary from 5 to 8. 19 refs.

  12. Study of the optical and magnetostatic properties of thin platelets of dysprosium and holmium ortho-ferrites

    International Nuclear Information System (INIS)

    Challeton, Didier

    1970-07-01

    Device applications of cylindrical magnetic domains - sometimes referred to as 'bubbles' - was first demonstrated by A.H. Bobeck in the rare earth ortho-ferrites. General magnetic and optical properties of the rare earth ortho-ferrites are considered. The theoretical study of the cylindrical magnetic domains and their stability conditions are presented in this paper. The single crystals were grown by the PbO flux method. The thin platelets (≅ 50 microns thick) preparation is specified and the magneto-optical measurements are presented. Absorption, birefringence and Faraday rotation were measured in HoFeO 3 and DyFeO 3 . The utilisation conditions of these materials are characterized by the measurements of the smallest stable domain diameter. (author) [fr

  13. The molecular beam epitaxy growth and characterization of zinc cadmium selenide/zinc cadmium magnesium selenide-indium phosphide quantum cascade structures for operation in the 3 - 5 um range

    Science.gov (United States)

    Charles, William O.

    The quantum cascade (QC) laser has captured the interest of researchers for almost three decades. In the early stages, researchers were very interested in proving the QC concept1 proposed by Kazarinov and Suris in 1971. This new concept gave researchers hope that very bulky energy inefficient infra-red (IR) lasers would be replaced with ones that are very compact, tunable and portable. Since the proposal of the QC laser concept and its first demonstration by researchers at Bell Laboratories2 in 1994, this technology has progressed to the point where it is now finding commercial applications in a variety of areas such as military counter measures, free space telecommunications, infra-red imaging and chemical spectroscopy.3-5 The success of this technology can be attributed to the coming of age of the techniques of molecular beam epitaxy (MBE) semiconductor growth and bandgap engineering. 6,7 Using MBE technology, the temperature of the source material can be stabilized by making use of a combination of proportional integral derivative (PID) controllers and thermocouple feedbacks. As a result, the material flux from the effusion cells can achieve stability better than (+/-) 1%. This flux stability together with a well-developed computer controlled shuttering mechanism make it possible to grow multi-quantum well (MQW) structures with excellent layer thickness precision (mono-layer scale) and interface quality. This stringent control of material flux is also a tool that is used by MBE growers to vary the material compositions for the growth of lattice matched and strain compensated QC structures. Today, MBE stands out as one of the premier methods for growing high performing QC lasers. The first successful demonstration of a QC laser2 was done using the InGaAs/InAlAs-InP material system. This demonstration was then repeated a few years later using GaAs/AlGaAs-InP.8 These III-V material systems were extensively studied to establish their material parameters. Given that material parameters are critically important in the process of modeling QC structures, it is not surprising that early success was achieved using these systems. Today, the best performing QC lasers operate in the 4--13 mum range and are produced using lattice matched InGaAs/InAlAs-InP. In order to produce short wavelength QC lasers, the well layer thicknesses in the active region of the device must be reduced in an effort to push the lasing energy states further apart. This reduction in well thicknesses results in the movement of the upper lasing state closer to the bandedge. This action increases the probability of the lost of lasing state electrons to the continuum. Therefore, in order to produce high performing short wavelength QC lasers, a large conduction band offset (CBO) is required. The CBO of lattice matched InGaAs/InAlAs-InP is 0.52 eV. In an attempt to produce high performing devices below 4 mum many researchers have resorted to the use of strain compensation9-11 . This approach has yielded very little improvement in performance due to electron scattering to the X and L intervalleys. This has lead to the exploration of wide bandgap material systems such as the antominides and nitrides. In this work the wide bandgap II-V Znx'Cd(1-x')Se/Zn xCdyMg(1-x-y)Se-InP will be explored for QC laser fabrication. To this end, QC lasers were designed for operation at 3--5 mum range. A Matlab-based program was written to calculate the energy level spacing within the active region of these devices. This simulation program was based on Schroindger's equation and the transfer matrix technique. Several calibration samples were grown to establish the doping levels and growth rate of the well and barrier materials. The growth rate was measured using scanning electron microscopy (SEM) and reflection high energy electron diffraction (RHEED) oscillations during MBE growth. X-ray diffraction measurements were performed to determine the lattice mismatch of the II-VI bulk layers, and therefore predict whether material composition adjustments were required to attain the lattice match condition. The samples that were grown were studied using photoluminescence (PL) to determine the bandgap of the well and barrier material. This information was then used to calculate the CBO of the II-VI MQW structure. In addition, PL studies were also carried out to look for material defects and assess the quality of the well/barrier interface. These II-VI QC samples were also subjected to Fourier transform infra-red (FTIR) absorption spectroscopy to determine the energy levels in the grown structures. After optimizing the active regions using simulation data and FTIR results, electroluminescence (EL) structures were grown and processed into QC emitters using a combination photolithography and electron beam contact deposition. The processed structures were then biased and investigated for IR emission at temperatures ranging from 80 K to room temperature.

  14. On the size and temperature dependence of the energy gap in cadmium-selenide quantum dots embedded in fluorophosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Lipatova, Zh. O., E-mail: zluka-yo@mail.ru; Kolobkova, E. V.; Babkina, A. N.; Nikonorov, N. V. [ITMO University (Russian Federation)

    2017-03-15

    The temperature and size dependences of the energy gap in CdSe quantum dots with diameters of 2.4, 4.0, and 5.2 nm embedded in fluorophosphate glasses are investigated. It is shown that the temperature coefficient of the band gap dE{sub g}/dT in the quantum dots differs from the bulk value and depends strictly on the dot size. It is found that, furthermore, the energy of each transition in these quantum dots is characterized by an individual temperature coefficient dE/dT.

  15. Loading of atorvastatin and linezolid in β-cyclodextrin–conjugated cadmium selenide/silica nanoparticles: A spectroscopic study

    International Nuclear Information System (INIS)

    Antony, Eva Janet; Shibu, Abhishek; Ramasamy, Sivaraj; Paulraj, Mosae Selvakumar; Enoch, Israel V.M.V.

    2016-01-01

    The preparation of β–cyclodextrin–conjugated cadmium selenide–silica nanoparticles, the loading of two drugs viz., Atorvastatin and linezolid in the cyclodextrin cavity, and the fluorescence energy transfer between CdSe/SiO_2 nanoparticles and the drugs encapsulated in the cyclodextrin cavity are reported in this paper. IR spectroscopy, X-ray diffractometry, transmission electron microscopy, and particle size analysis by light–scattering experiment were used as the tools of characterizing the size and the crystal system of the nanoparticles. The nanoparticles fall under hexagonal system. The silica–shell containing CdSe nanoparticles were functionalized by reaction with aminoethylamino–β–cyclodextrin. Fluorescence spectra of the nanoparticles in their free and drug–encapsulated forms were studied. The FÖrster distances between the encapsulated drugs and the CdSe nanoparticles are below 3 nm. The change in the FÖrster resonance energy parameters under physiological conditions may aid in tracking the release of drugs from the cavity of the cyclodextrin. - Highlights: • CdSe/SiO_2 nanoparticles of crystallite size 15 nm are prepared. • β-Cyclodextrin is attached to the surface of the nanoparticles. • Atorvastatin and linezolid get encapsulated in the cyclodextrin cavity. • FRET efficiency between the nanoparticles and the loaded drugs are determined.

  16. Loading of atorvastatin and linezolid in β-cyclodextrin–conjugated cadmium selenide/silica nanoparticles: A spectroscopic study

    Energy Technology Data Exchange (ETDEWEB)

    Antony, Eva Janet; Shibu, Abhishek [Department of Nanosciences & Technology, Karunya University, Coimbatore 641114, Tamil Nadu (India); Ramasamy, Sivaraj; Paulraj, Mosae Selvakumar [Department of Chemistry, Karunya University, Coimbatore 641114, Tamil Nadu (India); Enoch, Israel V.M.V., E-mail: drisraelenoch@gmail.com [Department of Nanosciences & Technology, Karunya University, Coimbatore 641114, Tamil Nadu (India); Department of Chemistry, Karunya University, Coimbatore 641114, Tamil Nadu (India)

    2016-08-01

    The preparation of β–cyclodextrin–conjugated cadmium selenide–silica nanoparticles, the loading of two drugs viz., Atorvastatin and linezolid in the cyclodextrin cavity, and the fluorescence energy transfer between CdSe/SiO{sub 2} nanoparticles and the drugs encapsulated in the cyclodextrin cavity are reported in this paper. IR spectroscopy, X-ray diffractometry, transmission electron microscopy, and particle size analysis by light–scattering experiment were used as the tools of characterizing the size and the crystal system of the nanoparticles. The nanoparticles fall under hexagonal system. The silica–shell containing CdSe nanoparticles were functionalized by reaction with aminoethylamino–β–cyclodextrin. Fluorescence spectra of the nanoparticles in their free and drug–encapsulated forms were studied. The FÖrster distances between the encapsulated drugs and the CdSe nanoparticles are below 3 nm. The change in the FÖrster resonance energy parameters under physiological conditions may aid in tracking the release of drugs from the cavity of the cyclodextrin. - Highlights: • CdSe/SiO{sub 2} nanoparticles of crystallite size 15 nm are prepared. • β-Cyclodextrin is attached to the surface of the nanoparticles. • Atorvastatin and linezolid get encapsulated in the cyclodextrin cavity. • FRET efficiency between the nanoparticles and the loaded drugs are determined.

  17. Growth and Evaluation of Nonlinear Optical Crystals for Laser Applications: Lithium Borate, Barium Borate and Silver Gallium Selenide.

    Science.gov (United States)

    1994-12-08

    communication 2. S. A. Kutovi, V. V. Laptev and S. Yu. Matsnev, " Lanthanum scandoborate as a new highly efficient active medium of solid state lasers," Sov. J...34Noncritical detection of tunable C02 laser radiation into green by upconversion in silver thio- gallate ," Applied Physics B53, 19 (1991). 3. N.-H

  18. Thermodynamic properties of selenoether-functionalized ionic liquids and their use for the synthesis of zinc selenide nanoparticles.

    Science.gov (United States)

    Klauke, Karsten; Zaitsau, Dzmitry H; Bülow, Mark; He, Li; Klopotowski, Maximilian; Knedel, Tim-Oliver; Barthel, Juri; Held, Christoph; Verevkin, Sergey P; Janiak, Christoph

    2018-04-03

    Three selenoether-functionalized ionic liquids (ILs) of N-[(phenylseleno)methylene]pyridinium (1), N-(methyl)- (2) and N-(butyl)-N'-[(phenylseleno)methylene]imidazolium (3) with bis(trifluoromethanesulfonyl)imide anions ([NTf2]) were prepared from pyridine, N-methylimidazole and N-butylimidazole with in situ obtained phenylselenomethyl chloride, followed by ion exchange to give the desired compounds. The crystal structures of the bromide and tetraphenylborate salts of the above cations (1-Br, 2-BPh4 and 3-BPh4) confirm the formation of the desired cations and indicate a multitude of different supramolecular interactions besides the dominating Coulomb interactions between the cations and anions. The vaporization enthalpies of the synthesized [NTf2]-containing ILs were determined by means of a quartz-crystal microbalance method (QCM) and their densities were measured with an oscillating U-tube. These thermodynamic data have been used to develop a method for assessment of miscibility of conventional solvents in the selenium-containing ILs by using Hildebrandt solubility parameters, as well as for modeling with the electrolyte perturbed-chain statistical associating fluid theory (ePC-SAFT) method. Furthermore, structure-property relations between selenoether-functionalized and similarly shaped corresponding aryl-substituted imidazolium- and pyridinium-based ILs were analyzed and showed that the contribution of the selenium moiety to the enthalpy of vaporization of an IL is equal to the contribution of a methylene (CH2) group. An incremental approach to predict vaporization enthalpies of ILs by a group contribution method has been developed. The reaction of these ILs with zinc acetate dihydrate under microwave irradiation led to ZnSe nanoparticles of an average diameter between 4 and 10 nm, depending on the reaction conditions.

  19. Singlet and triplet states of trions in Zinc Selenide-based quantum wells probed by magnetic fields to 50 Tesla

    International Nuclear Information System (INIS)

    Astakhov, G.V.; Yakovlev, D.R.; Crooker, Scott A.; Barrick, Todd; Dzyubenko, A.B.; Sander, Thomas; Kochereshko, V.P.; Ossau, W.; Faschinger, W.; Waag, A.

    2002-01-01

    Singlet and triplet states of positively (X + ) and negatively (X - ) charged excitons in ZnSe-based quantum wells have been studied by means of photoluminescence in pulsed magnetic fields up to 50 T. The binding energy of the X - singlet state shows a monotonic increase with magnetic field with a tendency to saturation, while that of the X + slightly decreases. The triplet X + and X - states, being unbound at zero magnetic field, noticeably increase their binding energy in high magnetic fields. The experimental evidence for the interaction between the triplet and singlet states of lTions leading to their anticrossing in magnetic fields has been found.

  20. Electrodeposited cadmium selenide films for solar cells; Electrodeposition de couches minces de CdSe: Application a la conversion photovoltaique

    Energy Technology Data Exchange (ETDEWEB)

    Bnamar, E.; Rami, M.; Fahoume, M.; Chraibi, F.; Ennaoui, A. [Universite Mohammed 5, Rabat (Morocco). Faculte des Sciences; Fahoume, M. [Universite Ibn Tofail, Faculte des Sciences, Kenitra (Morocco)

    1998-01-01

    Solar cells based on II-IV semiconductors are among the leading candidates for low-cost photovoltaic conversion of solar energy due to their high absorption coefficients and therefore the low materials consumption for their production. The synthesis of polycrystalline Cd Se thin films by cathodic electrodeposition on conducting substrates is described in this paper. Electrodeposition involves potentiostatic reduction from an acid aqueous bath. The influence of bath temperature and deposition potential on the crystallinity is discussed. For optimized deposition parameters, the XRD patterns reveal cubic and hexagonal Cd Se. Electron probe microanalysis shows an excess of Se in the samples. Photoelectrochemical studies of the films in aqueous polysulfide allowed us to determine the photovoltaic properties e.g.: semiconducting type, short-circuit current, open circuit voltage and fill factor. (authors) 5 refs.

  1. Chip-scale white flip-chip light-emitting diode containing indium phosphide/zinc selenide quantum dots

    Science.gov (United States)

    Fan, Bingfeng; Yan, Linchao; Lao, Yuqin; Ma, Yanfei; Chen, Zimin; Ma, Xuejin; Zhuo, Yi; Pei, Yanli; Wang, Gang

    2017-08-01

    A method for preparing a quantum dot (QD)-white light-emitting diode (WLED) is reported. Holes were etched in the SiO2 layer deposited on the sapphire substrate of the flip-chip LED by inductively coupled plasma, and these holes were then filled with QDs. An ultraviolet-curable resin was then spin-coated on top of the QD-containing SiO2 layer, and the resin was cured to act as a protecting layer. The reflective sidewall structure minimized sidelight leakage. The fabrication of the QD-WLED is simple in preparation and compatible with traditional LED processes, which was the minimum size of the WLED chip-scale integrated package. InP/ZnS core-shell QDs were used as the converter in the WLED. A blue light-emitting diode with a flip-chip structure was used as the excitation source. The QD-WLED exhibited color temperatures from 5900 to 6400 K and Commission Internationale De L'Elcairage color coordinates from (0.315, 0.325) to (0.325, 0.317), under drive currents from 100 to 400 mA. The QD-WLED exhibited stable optoelectronic properties.

  2. Functionalization of Cadmium Selenide Quantum Dots with Poly(ethylene glycol): Ligand Exchange, Surface Coverage, and Dispersion Stability.

    Science.gov (United States)

    Wenger, Whitney Nowak; Bates, Frank S; Aydil, Eray S

    2017-08-22

    Semiconductor quantum dots synthesized using rapid mixing of precursors by injection into a hot solution of solvents and surfactants have surface ligands that sterically stabilize the dispersions in nonpolar solvents. Often, these ligands are exchanged to disperse the quantum dots in polar solvents, but quantitative studies of quantum dot surfaces before and after ligand exchange are scarce. We studied exchanging trioctylphosphine (TOP) and trioctylphosphine oxide (TOPO) ligands on as-synthesized CdSe quantum dots dispersed in hexane with a 2000 g/mol thiolated poly(ethylene glycol) (PEG) polymer. Using infrared spectroscopy we quantify the absolute surface concentration of TOP/TOPO and PEG ligands per unit area before and after ligand exchange. While 50-85% of the TOP/TOPO ligands are removed upon ligand exchange, only a few are replaced with PEG. Surprisingly, the remaining TOP/TOPO ligands outnumber the PEG ligands, but these few PEG ligands are sufficient to disperse the quantum dots in polar solvents such as chloroform, tetrahydrofuran, and water. Moreover, as-synthesized quantum dots once easily dispersed in hexane are no longer dispersible in nonpolar solvents after ligand exchange. A subtle coverage-dependent balance between attractive PEG-solvent interactions and repulsive TOP/TOPO-solvent interactions determines the dispersion stability.

  3. Long term aging of selenide glasses: evidence of sub-Tg endotherms and pre-Tg exotherms

    Science.gov (United States)

    Chen, Ping; Boolchand, P.; Georgiev, D. G.

    2010-02-01

    Long term aging, extending from months to several years, is studied on several families of chalcogenide glasses including the Ge-Se, As-Se, and Ge-As-Se systems. Special attention is given to the As-Se binary, a system that displays a rich variety of aging behavior intimately tied to sample synthesis conditions and the ambient environment in which samples are aged. Calorimetric (modulated DSC) and Raman scattering experiments are undertaken. Our results show all samples display a sub-Tg endotherm typically 10-70 °C below Tg in glassy networks possessing a mean coordination number r in the 2.25 < r < 2.45 range. Two sets of AsxSe100-x samples aged for eight years were compared, set A consisted of slow cooled samples aged in the dark, and set B consisted of melt-quenched samples aged at laboratory environment. Samples of set B in the As concentration range, 35% < x < 60%, display a pre-Tg exotherm, but the feature is not observed in samples of set A. The aging behavior of set A presumably represents intrinsic aging in these glasses, while that of set B is extrinsic due to the presence of light. The reversibility window persists in both sets of samples, but is less well defined in set B. These findings contrast with a recent study by Golovchak et al (2008 Phys. Rev. B 78 014202), which finds the onset of the reversibility window moved up to the stoichiometric composition (x = 40%). Here we show that the up-shifted window is better understood as resulting due to demixing of As4Se4 and As4Se3 molecules from the backbone, i.e., nanoscale phase separation (NSPS). We attribute sub-Tg endotherms to compaction of the flexible part of the networks upon long term aging, while the pre-Tg exotherm is to NSPS. The narrowing and sharpening of the reversibility window upon aging is interpreted as the slow 'self-organizing' stress relaxation of the phases just outside the intermediate phase, which itself is stress free and displays little aging.

  4. Investigation into short-range order, electric conductivity and optical absorption edge of indium selenide thin amorphous films

    International Nuclear Information System (INIS)

    Bilyj, M.N.; Didyk, G.V.; Stetsiv, Ya.I.; Yurechko, R.Ya.

    1980-01-01

    Thin amorphous films of InSe have been obtained by the method of discrete vacuum evaporation of about 10 -2 Pa. The short-range order is investigated according to the radial distribution curves. The temperature and film thickness are shown to affect the character of conductivity. The width of the forbidden band determined by the fundamental absorption edge is found to depend on the time of film annealing

  5. Bis(η2-ethylene[azanidediylbis(diisopropylphosphine selenide-κ2Se,Se′]iridium(III

    Directory of Open Access Journals (Sweden)

    Qian-Feng Zhang

    2009-12-01

    Full Text Available In the title compound, [Ir(η2-C2H42(C12H28NP2Se2], the central Ir atom is chelated by the [N(iPr2PSe2]− ligand via two Se atoms and is coordinated by two η2-ethylene molecules via four C atoms in an octahedral coordination geometry.

  6. 71Ga-77Se connectivities and proximities in gallium selenide crystal and glass probed by solid-state NMR

    Science.gov (United States)

    Nagashima, Hiroki; Trébosc, Julien; Calvez, Laurent; Pourpoint, Frédérique; Mear, François; Lafon, Olivier; Amoureux, Jean-Paul

    2017-09-01

    We introduce two-dimensional (2D) 71Ga-77Se through-bond and through-space correlation experiments. Such correlations are achieved using (i) the J-mediated Refocused Insensitive Nuclei Enhanced by Polarization Transfer (J-RINEPT) method with 71Ga excitation and 77Se Carr-Purcell-Meiboon-Gill (CPMG) detection, as well as (ii) the J- or dipolar-mediated Hetero-nuclear Multiple-Quantum Correlation (J- or D-HMQC) schemes with 71Ga excitation and quadrupolar CPMG (QCPMG) detection. These methods are applied to the crystalline β-Ga2Se3 and the 0.2Ga2Se3-0.8GeSe2 glass. Such glass leads to a homogeneous and reproducible glass-ceramic, which is a good alternative to single-crystalline Ge and polycrystalline ZnSe materials for making lenses transparent in the IR range for thermal imaging applications. We show that 2D 71Ga-77Se correlation experiments allow resolving the 77Se signals of molecular units, which are not resolved in the 1D 77Se CPMG spectrum. Additionally, the build-up curves of the J-RINEPT and the J-HMQC experiments allow the estimate of the 71Ga-77Se J-couplings via one and three-bonds in the three-dimensional network of β-Ga2Se3. Furthermore, these build-up curves show that the one-bond 1J71Ga-77Se couplings in the 0.2Ga2Se3-0.8GeSe2 glass are similar to those measured for β-Ga2Se3. We also report 2D 71Ga Satellite Transition Magic-Angle Spinning (STMAS) spectrum of β-Ga2Se3 using QCPMG detection at high magnetic field and high Magic-Angle Spinning frequency using large radio frequency field. Such spectrum allows separating the signal of β-Ga2Se3 and that of an impurity.

  7. Properties of zinc selenide grown by chemical vapor transport and its application to room-temperature radiation detection

    International Nuclear Information System (INIS)

    Brunett, B.A.; Toney, J.E.; Schlesinger, T.E.; Yoon, H.; Goorsky, M.S.; Rudolph, P.

    1998-01-01

    The authors have characterized ZnSe material grown by chemical vapor transport in iodine using triple-axis X-ray diffraction (TAD), photo-induced current transient spectroscopy (PICTS), photoluminescence (PL), current-voltage measurements and gamma-ray spectroscopy. The material was found to have inadequate carrier transport for nuclear spectrometer use, but there was a discernible difference in performance between crystals which could be correlated with crystallinity as determined by the TAD rocking curves

  8. Few-layer bismuth selenides exfoliated by hemin inhibit amyloid-β1–42 fibril formation

    Science.gov (United States)

    Peng, Jian; Xiong, Yunjing; Lin, Zhiqin; Sun, Liping; Weng, Jian

    2015-01-01

    Inhibiting amyloid-β (Aβ) fibril formation is the primary therapeutic strategy for Alzheimer’s disease. Several small molecules and nanomaterials have been used to inhibit Aβ fibril formation. However, insufficient inhibition efficiency or poor metabolization limits their further applications. Here, we used hemin to exfoliate few-layer Bi2Se3 in aqueous solution. Then we separated few-layer Bi2Se3 with different sizes and thicknesses by fractional centrifugation, and used them to attempt to inhibit Aβ1-42 aggregation. The results show that smaller and thinner few-layer Bi2Se3 had the highest inhibition efficiency. We further investigated the interaction between few-layer Bi2Se3 and Aβ1-42 monomers. The results indicate that the inhibition effect may be due to the high adsorption capacity of few-layer Bi2Se3 for Aβ1−42 monomers. Few-layer Bi2Se3 also decreased Aβ-mediated peroxidase-like activity and cytotoxicity according to in vitro neurotoxicity studies under physiological conditions. Therefore, our work shows the potential for applications of few-layer Bi2Se3 in the biomedical field. PMID:26018135

  9. Observation of a hidden hole-like band approaching the fermi level in K-doped iron selenide superconductor

    International Nuclear Information System (INIS)

    Sunagawa, Masanori; Terashima, Kensei; Hamada, Takahiro

    2016-01-01

    One of the ultimate goals of the study of iron-based superconductors is to identify the common feature that produces the high critical temperature (T c ). In the early days, based on a weak-coupling viewpoint, the nesting between hole- and electron-like Fermi surfaces (FSs) leading to the so-called s± state was considered to be one such key feature. However, this theory has faced a serious challenge ever since the discovery of alkali-metal-doped FeSe (AFS) superconductors, in which only electron-like FSs with a nodeless superconducting gap are observed. Several theories have been proposed, but a consistent understanding is yet to be achieved. Here we show experimentally that a hole-like band exists in K x Fe 2-y Se 2 , which presumably forms a hole-like Fermi surface. The present study suggests that AFS can be categorized in the same group as iron arsenides with both hole- and electron-like FSs present. This result provides a foundation for a comprehensive understanding of the superconductivity in iron-based superconductors. (author)

  10. Hexanuclear, heterometallic, Ni₃Ln₃ complexes possessing O-capped homo- and heterometallic structural subunits: SMM behavior of the dysprosium analogue.

    Science.gov (United States)

    Goura, Joydeb; Guillaume, Rogez; Rivière, Eric; Chandrasekhar, Vadapalli

    2014-08-04

    The reaction of hetero donor chelating mannich base ligand 6,6'-{(2-(dimethylamino)ethylazanediyl)bis(methylene)}bis(2-methoxy-4-methylphenol) with Ni(ClO4)2·6H2O and lanthanide(III) salts [Dy(III) (1); Tb(III) (2); Gd (III) (3); Ho(III) (4); and Er(III) (5)] in the presence of triethylamine and pivalic acid afforded a series of heterometallic hexanuclear Ni(II)-Ln(III) coordination compounds, [Ni3Ln3(μ3-O)(μ3-OH)3(L)3(μ-OOCCMe3)3]·(ClO4)·wCH3CN·xCH2Cl2·yCH3OH·zH2O [for 1, w = 8, x = 3, y = 0, z = 5.5; for 2, w = 0, x = 5, y = 0, z = 6.5; for 3, w = 15, x = 18, y = 3, z = 7.5; for 4, w = 15, x = 20, y = 6, z = 9.5; and for 5, w = 0, x = 3, y = 2, z = 3]. The molecular structure of these complexes reveals the presence of a monocationic hexanuclear derivative containing one perchlorate counteranion. The asymmetric unit of each of the hexanuclear derivatives comprises the dinuclear motif [NiLn(L)(μ3-O)(μ3-OH)(μ-Piv)]. The cation contains three interlinked O-capped clusters: one Ln(III)3O and three Ni(II)Ln(III)2O. Each of the lanthanide centers is eight- coordinated (distorted trigonal-dodecahedron), while the nickel centers are hexacoordinate (distorted octahedral). The study of the magnetic properties of all compounds are reported and suggests single molecule magnet behavior for the Dy(III) derivative (1).

  11. Enhancement of lanthanide evaporation by complexation: Dysprosium tri-iodide mixed with indium iodide and thulium tri-iodide mixed with thallium iodide

    Energy Technology Data Exchange (ETDEWEB)

    Curry, J. J.; Henins, A.; Hardis, J. E. [National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899 (United States); Estupiñán, E. G. [OSRAM SYLVANIA Inc., 71 Cherry Hill Drive, Beverly, Massachusetts 01915 (United States); Lapatovich, W. P. [Walter Lapatovich Consulting, 51 Pye Brook Lane, Boxford, Massachusetts 01921 (United States); Shastri, S. D. [Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)

    2013-09-28

    The vapors in equilibrium with condensates of DyI{sub 3}, DyI{sub 3}/InI, TmI{sub 3}, and TmI{sub 3}/TlI were observed over the temperature range from 900 K to 1400 K using x-ray induced fluorescence. The total densities of each element (Dy, Tm, In, Tl, and I) in the vapor, summed over all atomic and molecular species, were determined. Dramatic enhancements in the total vapor densities of Dy and Tm were observed in the vapors over DyI{sub 3}/InI and TmI{sub 3}/TlI as compared to the vapors over pure DyI{sub 3} and pure TmI{sub 3}, respectively. An enhancement factor exceeding 10 was observed for Dy at T≈ 1020 K, decreasing to 0 at T≈ 1250 K. An enhancement factor exceeding 20 was observed for Tm at T≈ 1040 K, decreasing to 0 at T≈ 1300 K. Such enhancements are expected from the formation of the vapor-phase hetero-complexes DyInI{sub 4} and TmTlI{sub 4}. Numerical simulations of the thermo-chemical equilibrium suggest the importance of additional complexes in liquid phases. A description of the measurement technique is given. Improvements in the absolute calibration lead to an approximately 40% correction to previously reported preliminary results [J. J. Curry et al., Chem. Phys. Lett. 507, 52 (2011); Appl. Phys. Lett. 100, 083505 (2012)].

  12. Complexation behaviour of DADCA and DAPDA with dysprosium-166/holmium-166 parent daughter system and its potential for use in radioimmunotherapy

    International Nuclear Information System (INIS)

    Orsini, S.; University of Technology, Broadway, NSW; Di Bartolo, N.; Smith, S.; Baker, T.

    1998-01-01

    Full text: A novel approach for the delivery of therapeutic doses from 166 Ho to cancerous tissue is via the decay of its parent, 166 Dy. When designing radioimmunoconjugte, a crucial question is to determine whether the ligand used in the radiolabeling process is capable of holding the 166 Ho on decay of the parent, 166 Dy. In this study, two pendant arm macrocycles 1, 10-Diaza-4, 7, 13, 16-tetraoxacyclooctadecane-N, N'-diacetic acid, (DACDA) and 1, 10-Diaza-4, 7, 13-trioxacyclopentadecane-N, N'-diacetic acid, (DAPDA) that were reported to forms reasonably stable complexes with Dy and Ho, were synthesised. The synthesis of the two pendant arm macrocycles was first attempted using methods outlined by Chang and Rowland. The yields obtained through this method were low (10 % for both ligands) and it was considered important to investigate alternative approaches to the synthesis. The new method involved an alkylation reaction in the presence of acetonitrile and sodium bicarbonate. The method took considerably less time and the yields increased to 88 %. The ligands were characterised using 1 H NMR, 13 C NMR and mass spectrometry. The chemical and radiolytic stabilities of 166 Dy and 166 Ho complexes of the two ligands were investigated at pH = 5 and the ligands potential for use in the in vivo generator system evaluated

  13. CCDC 1402057: Experimental Crystal Structure Determination : pentakis(tetra-n-butylammonium) tetrakis(mu-oxalato)-dodecachloro-tetranitrosyl-ethanol-tetra-ruthenium-dysprosium sesquihydrate

    KAUST Repository

    Kuhn, Paul-Steffen; Cremer, Laura; Gavriluta, Anatolie; Jovanović, Katarina K.; Filipović, Lana; Hummer, Alfred A.; Bü chel, Gabriel E.; Dojčinović, Biljana P.; Meier, Samuel M.; Rompel, Annette; Radulović, Siniša; Tommasino, Jean Bernard; Luneau, Dominique; Arion, Vladimir B.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  14. 3D dysprosium density in the metal-halide lamp measured by emission and laser absorption spectroscopy in a centrifuge at 1-10g

    NARCIS (Netherlands)

    Flikweert, A.J.; Nimalasuriya, T.; Thubé, G.M.; Kroesen, G.M.W.; Stoffels, W.W.

    2007-01-01

    The metal-halide lamp is a High Intensity Discharge (HID) lamp with a high efficiency. The salt additive (DyI3) acts as prime radiator. The present lamp suffers from non-uniform light output, caused by diffusion and convection processes. To gain a better understanding of the lamp, the convection is

  15. Effect of dysprosium substitution on electrical properties of SrBi{sub 4}Ti{sub 4}O{sub 15}

    Energy Technology Data Exchange (ETDEWEB)

    Mamatha, B., E-mail: boinanemamatha@gmail.com; Sarah, P.

    2014-10-15

    SrBi{sub 4−x}Dy{sub x}Ti{sub 4}O{sub 15} (with x = 0.02, 0.04, 0.06 and 0.08) powders have been synthesized using the stoichiometric amounts of nitrates and oxides of the constituent materials through sol–gel method. The compound so formed is characterized using X-ray diffraction. The density and lattice parameters are calculated. The impedance and electrical conductivity properties are investigated. The imaginary part of impedance as a function of frequency shows Debye like relaxation. Impedance data presented in the Nyquist plot which is used to identify an equivalent circuit and the fundamental circuit parameters are determined at different temperatures. The results of bulk a.c. conductivity as a function of frequency at different temperatures are presented. The dielectric behavior was investigated. Permittivity was calculated based on the relaxation frequency using an alternative approach based on the variation of the imaginary impedance component as a function of reciprocal angular frequency. The frequency dependence of real and imaginary permittivities was also investigated. - Highlights: • SrBi{sub 4−x}Dy{sub x}Ti{sub 4}O{sub 15} (x = 0.02, 0.04, 0.06 and 0.08) powders are produced by sol–gel method. Phase formation is confirmed by XRD analysis. • Frequency dependent imaginary part of impedance shows distribution of relaxation in system. • Broadness of Z″ peak shows distribution of relaxation frequency. • Increase in peak width at ½ maxima of Z″ with increase of temperature shows increase of relaxation frequency distribution. • Cole–Cole plots are resolved into two different circles, ascribed to different mechanisms of polarization and relaxation phenomena.

  16. Transition metal redox switches for reversible "on/off" and "slow/fast" single-molecule magnet behaviour in dysprosium and erbium bis-diamidoferrocene complexes.

    Science.gov (United States)

    Dickie, Courtney M; Laughlin, Alexander L; Wofford, Joshua D; Bhuvanesh, Nattamai S; Nippe, Michael

    2017-12-01

    Single-molecule magnets (SMMs) are considered viable candidates for next-generation data storage and quantum computing. Systems featuring switchability of their magnetization dynamics are particularly interesting with respect to accessing more complex logic gates and device architectures. Here we show that transition metal based redox events can be exploited to enable reversible switchability of slow magnetic relaxation of magnetically anisotropic lanthanide ions. Specifically, we report anionic homoleptic bis-diamidoferrocene complexes of Dy 3+ (oblate) and Er 3+ (prolate) which can be reversibly oxidized by one electron to yield their respective charge neutral redox partners (Dy: [1] - , 1 ; Er: [2] - , 2 ). Importantly, compounds 1 and 2 are thermally stable which allowed for detailed studies of their magnetization dynamics. We show that the Dy 3+ [1] - / 1 system can function as an "on"/"off" or a "slow"/"fast" redox switchable SMM system in the absence or presence of applied dc fields, respectively. The Er 3+ based [2] - / 2 system features "on"/"off" switchability of SMM properties in the presence of applied fields. Results from electrochemical investigations, UV-vis-NIR spectroscopy, and 57 Fe Mössbauer spectroscopy indicate the presence of significant electronic communication between the mixed-valent Fe ions in 1 and 2 in both solution and solid state. This comparative evaluation of redox-switchable magnetization dynamics in low coordinate lanthanide complexes may be used as a potential blueprint toward the development of future switchable magnetic materials.

  17. Comparison of MR imaging after administration of dysprosium-based magnetic-susceptibility contrast media with diffusion-weighted MR imaging in evaluation of regional cerebral ischemia

    International Nuclear Information System (INIS)

    Moseley, M.E.; Kucharczyk, J.; Kurhanewicz, J.; Mintorovitch, J.; Cohen, Y.; Rocklage, S.; Quay, S.C.; Norman, D.

    1989-01-01

    This paper reports on a study to establish whether a nonionic T2-shortening contrast agent, Dy-DTPA-bis(methylamide) (Dy-DTPA-BMA), would facilitate early detection of stroke-induced cerebral perfusion deficits. The sensitivity of susceptibility-enhanced MR imaging was compared with that of diffusion-weighted MR imaging in the same cats subjected to unilateral occlusion of the middle cerebral artery (MCA). A 2-T unit, equipped with self-shielded gradient coils (± 20 G/cm, 15-cm bore size), was used in conjunction with an 8.5-cm inner diameter low-pass bird cage proton imaging coil. Diffusion-weighted images displayed increased signal intensity in the ischemic MCA territory less than 1 hour after occlusion, whereas T2-weighted MR images without contrast enhancement usually failed to depict injury for 2--3 hours after toke. With contrast administration (0.5 mmoles/kg of Dy-DTPA-BMA), however, T2-weighted images revealed perfusion deficits (hyperintensity) within 1 hour after MCA occlusion, and these corresponded to the anatomic regions of ischemic injury shown on diffusion-weighted MR images

  18. Magnetic anisotropy and neutron scattering studies of some rare earth metals

    International Nuclear Information System (INIS)

    Day, R.

    1978-08-01

    The thesis is concerned with magnetic anisotropy of dysprosium and alloys of gadolinium: yttrium, and also neutron scattering studies of dysprosium. The experiments are discussed under the topic headings: magnetic anisotropy, rare earths, torque measurements, elastic neutron scattering, inelastic neutron scattering, dysprosium measurements, and results for the gadolinium: yttrium alloys. (U.K.)

  19. Studies of the absorbance peak on the N719 dye influence by combination between Cadmium Selenide (CdSeQDs and Zinc Sulfide(ZnSQDs

    Directory of Open Access Journals (Sweden)

    Saad Mohammad Azren

    2018-01-01

    Full Text Available The absorption rate of the photoanode can be influenced by the combination between the difference semiconductor quantum dot sensitizer. Six samples were prepared with difference weight percent (wt% of ZnS from 0% to 50% and constant wt% of CdSe which then will be called as semiconductor QDs were immersed in 0.5mM of N719 dye. The purity of ZnS powder and CdSe powder was determined using x-ray diffraction (XRD.The ultraviolet-visible spectrophotometry (Uv-Vis use to investigate the absorption spectrum and absorbance peak of this sample. 50 wt% of ZnS is the best composition to increase the absorbance peak of the photoanode. The Cyclic voltammetry (CV of varying wt% of ZnS, found that the 40 wt% of ZnS is suitable combination for a DSSC’s photoanode and produced the higher current.

  20. Cobalt selenide hollow nanorods array with exceptionally high electrocatalytic activity for high-efficiency quasi-solid-state dye-sensitized solar cells

    Science.gov (United States)

    Jin, Zhitong; Zhang, Meirong; Wang, Min; Feng, Chuanqi; Wang, Zhong-Sheng

    2018-02-01

    In quasi-solid-state dye-sensitized solar cells (QSDSSCs), electron transport through a random network of catalyst in the counter electrode (CE) and electrolyte diffusion therein are limited by the grain boundaries of catalyst particles, thus diminishing the electrocatalytic performance of CE and the corresponding photovoltaic performance of QSDSSCs. We demonstrate herein an ordered Co0.85Se hollow nanorods array film as the Pt-free CE of QSDSSCs. The Co0.85Se hollow nanorods array displays excellent electrocatalytic activity for the reduction of I3- in the quasi-solid-state electrolyte with extremely low charge transfer resistance at the CE/electrolyte interface, and the diffusion of redox species within the Co0.85Se hollow nanorods array CE is pretty fast. The QSDSSC device with the Co0.85Se hollow nanorods array CE produces much higher photovoltaic conversion efficiency (8.35%) than that (4.94%) with the Co0.85Se randomly packed nanorods CE, against the control device with the Pt CE (7.75%). Moreover, the QSDSSC device based on the Co0.85Se hollow nanorods array CE presents good long-term stability with only 4% drop of power conversion efficiency after 1086 h one-sun soaking.

  1. Synthesis, crystal structure, optical, and electronic study of the new ternary thorium selenide Ba{sub 3}ThSe{sub 3}(Se{sub 2}){sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Prakash, Jai [Department of Chemistry, Northwestern University, Evanston, IL 60208-3113 (United States); Mesbah, Adel [Department of Chemistry, Northwestern University, Evanston, IL 60208-3113 (United States); ICSM, UMR 5257 CEA/CNRS/UM2/ENSCM, Site de Marcoule-Bât. 426, BP 17171, 30207 Bagnols-sur-Cèze cedex (France); Beard, Jessica [Department of Chemistry, Northwestern University, Evanston, IL 60208-3113 (United States); Lebègue, Sébastien [Laboratoire de Cristallographie, Résonance Magnétique et Modélisations (CRM2, UMR CNRS 7036), Institut Jean Barriol, Université de Lorraine, BP 239, Boulevard des Aiguillettes, 54506 Vandoeuvre-lès-Nancy (France); Malliakas, Christos D. [Department of Chemistry, Northwestern University, Evanston, IL 60208-3113 (United States); Ibers, James A., E-mail: ibers@chem.northwestern.edu [Department of Chemistry, Northwestern University, Evanston, IL 60208-3113 (United States)

    2015-11-15

    The compound Ba{sub 3}ThSe{sub 3}(Se{sub 2}){sub 2} has been synthesized by solid-state methods at 1173 K. Its crystal structure features one-dimensional chains of {sup 1}{sub ∞}[Th(Se){sub 3}(Se{sub 2}){sub 2}{sup 6−}] separated by Ba{sup 2+} cations. Each Th atom in these chains is coordinated to two Se–Se single-bonded pairs and four Se atoms to give rise to a pseudooctahedral geometry around Th. The Th–Se distances are consistent with Th{sup 4+} and hence charge balance of Ba{sub 3}ThSe{sub 3}(Se{sub 2}){sub 2} is achieved as 3×Ba{sup 2+}, 1×Th{sup 4+}, 3×Se{sup 2−}, and 2×Se{sub 2}{sup 2−}. From optical measurements the band gap of Ba{sub 3}ThSe{sub 3}(Se{sub 2}){sub 2} is 1.96(2) eV. DFT calculations indicate that the compound is a semiconductor. - Graphical abstract: Local coordination environment of Th atoms in the Ba{sub 3}ThSe{sub 3}(Se{sub 2}){sub 2} structure. - Highlights: • Ba{sub 3}ThSe{sub 3}(Se{sub 2}){sub 2} has been synthesized by solid-state methods at 1173 K. • The structure features chains of {sup 1}{sub ∞}[Th(Se){sub 3}(Se{sub 2}){sub 2}{sup 6−}] separated by Ba{sup 2+} cations. • Ba{sub 3}ThSe{sub 3}(Se{sub 2}){sub 2} is a semiconductor with a band gap of 1.96(2) eV.

  2. Photoluminescence spectral study of single cadmium selenide/zinc sulfide colloidal nanocrystals in poly(methyl methacrylate) and quantum dots molecules

    Science.gov (United States)

    Shen, Yaoming

    Quantum dots (QDs)and Nano-crystals (NCs) have been studies for decades. Because of the nanoscale quantum confinement, delta shape like energy density states and narrowband emitters properties, they hold great promise for numerous optoelectronics and photonics applications. They could be used for tunable lasers, white LED, Nano-OLED, non-volatile memory and solar cells. They are also the most promising candidates for the quantum computing. The benefits for NCs over QDs is that NCs can be incorporated into a variety of polymers as well as thin films of bulk semiconductors. These exceptional flexibility and structural control distinguish NCs from the more traditional QD structures fabricated using epitaxial growth techniques. In my research of work, I studied the photoluminescence (PL) and absorption character of ensemble NCs incorporated in Polymethyl methacrylate (PMMA). To understand the behavior of the NCs in PMMA, it is important to measure a singe NC to avoid the inhomogenous broading of many NCs. So I particularly studied the behavior of a single NC in PMMA matrix. A microphotoluminescence setup to optically isolate a single nanocrystal is used. Random spectral shift and blinking behavior (on and off) are found. Addition to that, two color spectral shifting, is a major phenomena found in the system. Other interesting results such as PL intensity changes (decreasing or increasing with time) and quenching effect are observed and explained too. From the correlation function, we can distinguish the phonon replicas. The energy of these phonons can be calculated very accurately from the experiment result. The Huang-Rhys factors can be estimated too. Self-assembled semiconductor quantum dots (QDs), from highly strained-layer heteroepitaxy in the Stranski-Krastanow (S-K) growth mode, have been intensively studied because of the delta-function-like density of states, which is significant for optoelectronic applications. Spontaneous formation of semiconductor quantum-dot molecules (QDMs), which are clusters of a few QDs, has attracted attention as a possible implementation of future quantum devices such as quantum cellular antomata. With the advances in crystal growth techniques, the fabrication methods for nanostructures have been improved continuously. Lateral QDMs have been achieved. As a side topic, lateral QDMs have been studied and the result is presented in the last chapter.

  3. Study the physical and optoelectronic properties of silver gallium indium selenide AgGaInSe2/Si heterojunction solar cell

    Science.gov (United States)

    Hassun, Hanan K.

    2018-05-01

    AgGa1-x InxSe2 (AGIS) thin films was deposited on Si and glass substrates by thermal evaporation at RT and different ratios of Indium (x=0.2, 0.5, 0.8). The synthetics properties of AGIS thin film have been examined using X-ray diffraction and AFM. AGIS thin films possessed a polycrystalline tetragonal structure. Average diameter and roughness calculated from AFM images shows an increase in its value with increasing the ratios of Indium. Hall measurements showed n-type conduction with high mobility. The AgGa0.2In0.8Se2 thin film solar cell with a band gap of 1.65eV exhibit a total efficiency of 6.3% with open-circuit voltage Voc 0.38V, short circuit current Jsc 29 mA/cm2, fill factor FF 0.571 and total area 1 cm2. The built-in potential Vbi, concentration of majoritarian carrier ND and depletion width w are definite under different ratios of Indium from C-V amount.

  4. Litochlebite, Ag2PbBi4Se8, a new selenide mineral species from Zalesi, Czech Republic: description and crystal structure

    DEFF Research Database (Denmark)

    Makovicky, Emil; Topa, Dan; Sejkora, Jiri

    2011-01-01

    Moravia, Czech Republic. It occurs as irregular grains up to 200 mm, which form aggregates up to 1–2 mm in size in a quartz gangue. These aggregates are replaced along the margins and fractures by a heterogeneous supergene Bi–Se–O phase. Other associated minerals included uraninite, hematite...... [Fo > 4s(Fo)] collected on a Bruker AXS diffractometer with a CCD detector and MoKa radiation. The crystal structure contains one lead site, four independent Bi sites, four silver sites and eight independent Se sites. One Ag site is an octahedrally coordinated (2 + 4) site in the pseudotetragonal...

  5. Towards a systematic assessment of errors in diffusion Monte Carlo calculations of semiconductors: Case study of zinc selenide and zinc oxide

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Jaehyung [Department of Mechanical Science and Engineering, 1206 W Green Street, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Wagner, Lucas K. [Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Ertekin, Elif, E-mail: ertekin@illinois.edu [Department of Mechanical Science and Engineering, 1206 W Green Street, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); International Institute for Carbon Neutral Energy Research - WPI-I" 2CNER, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395 (Japan)

    2015-12-14

    The fixed node diffusion Monte Carlo (DMC) method has attracted interest in recent years as a way to calculate properties of solid materials with high accuracy. However, the framework for the calculation of properties such as total energies, atomization energies, and excited state energies is not yet fully established. Several outstanding questions remain as to the effect of pseudopotentials, the magnitude of the fixed node error, and the size of supercell finite size effects. Here, we consider in detail the semiconductors ZnSe and ZnO and carry out systematic studies to assess the magnitude of the energy differences arising from controlled and uncontrolled approximations in DMC. The former include time step errors and supercell finite size effects for ground and optically excited states, and the latter include pseudopotentials, the pseudopotential localization approximation, and the fixed node approximation. We find that for these compounds, the errors can be controlled to good precision using modern computational resources and that quantum Monte Carlo calculations using Dirac-Fock pseudopotentials can offer good estimates of both cohesive energy and the gap of these systems. We do however observe differences in calculated optical gaps that arise when different pseudopotentials are used.

  6. Power Scaling Feasibility or Chromium-Doped II-VI Laser Sources and the Demonstration of a Chromium-Doped Zinc Selenide Face-Cooled Disk Laser

    National Research Council Canada - National Science Library

    McKay, Jason

    2002-01-01

    ...+:ZnSe disk laser design that can produce sufficient output power. Cr2+:II-VI laser materials are found to be susceptible to overheating and thermal lensing, but are otherwise satisfactory laser materials...

  7. NMR spectroscopy of organic compounds of selenium and tellurium. Communication 9. Chemical shifts of /sup 13/C in isological series of unsaturated ethers, sulfides, selenides and tellurides

    Energy Technology Data Exchange (ETDEWEB)

    Kalabin, G.A.; Bzhezovskii, V.M.; Kushnarev, D.F.; Proidakov, A.G. (Irkutskii Gosudarstvennyj Univ. (USSR))

    1981-06-01

    The effects of heteroatoms Eh(Eh=O, S, Se, Te) on /sup 13/C chemical shifts in eleven isological series of R/sup 1/-Eh-R/sup 2/ unsaturated compounds are compared. A linear relation between /sup 13/C nuclei screening and tEh electronegativity is observed. An assumption is suggested that both likeness of the effects of 6A and 7A group elements on /sup 13/C chemical shifts of R/sup 1/ and R/sup 2/ substituents and their difference for elements of the 4A group are caused by unbonded interactions of the substituents with unshared electron pairs of heteroatoms.

  8. Preparation, characterization, and luminescence properties of dysprosium perchlorate with MABA-Si and phen or dipy complexes as well as SiO{sub 2}@Dy(MABA-Si)L core-shell structure nanometermeter luminescent composites

    Energy Technology Data Exchange (ETDEWEB)

    Li, Wen-Xian, E-mail: nmglwx@163.com [College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021 (China); Zheng, Yu-Shan [Inner Mongolia Autonomous Region Product Quality Inspection Institute, Hohhot 010010 (China); Cao, Xiao-fang; Bai, Juan; Fu, Zhi-Fang; Bao, Jin-Rong; Li, Yi-Lian [College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021 (China)

    2016-10-15

    Two novel ternary rare earth complexes Dy(MABA-Si)·L{sub 2}(ClO{sub 4}){sub 3}·2H{sub 2}O (L= Phen or Dipy) were prepared using HOOCC{sub 6}H{sub 4}N(CONH(CH{sub 2}){sub 3}Si-(OCH{sub 2}CH{sub 3}){sub 3}){sub 2} which was abbreviated or denoted as MABA-Si. MABA-Si was the first ligand, L was the second ligand. The corresponding two SiO{sub 2}@Dy(MABA-Si)L nanometermeter luminescent composites were synthesized as well, and the silica spheres is the core, and the ternary rare earth complex Dy(MABA-Si)·L{sub 2}(ClO{sub 4}){sub 3}·2H{sub 2}O was the shell layer, who was abbreviated or denoted as Dy((MABA-Si)L). The ternary complexes have been characterized by element analysis, molar conductivity, IR spectra and {sup 1}HNMR spectra. The results showed that the chemical formula of the complex was Dy(MABA-Si)·L{sub 2}(ClO{sub 4}){sub 3}·2H{sub 2}O. The fluorescent spectra illustrated that the complexes displayed its characteristic luminescence in solid state, and the luminescence was superior than Dy{sup 3+}. The core-shell structure of SiO{sub 2}@Dy(MABA-Si)L nanometermeter luminescent composite was characterized by SEM, TEM and IR spectra. Based on the SEM photographs, the core-shell structure particles showed its regular microstructure including smooth surface, and good dispersity. The ternary complex coated on the mono-dispersed SiO{sub 2} spheres by self-assembly. The fluorescent spectra illustrated that the core-shell structure of SiO{sub 2}@Dy(MABA-Si)L nanometermeter luminescent composites exhibited stronger fluorescent than the ternary complexes. The fluorescence lifetime of the complexes and core-shell structure composites was measured as well.

  9. Dysprosium-doped PbGa2S4 laser generating at 4.3 μm directly pumped by 1.7 μm laser diode.

    Science.gov (United States)

    Jelínková, Helena; Doroshenko, Maxim E; Jelínek, Michal; Sulc, Jan; Osiko, Vyacheslav V; Badikov, Valerii V; Badikov, Dmitrii V

    2013-08-15

    In this Letter, we demonstrate the pulsed and CW operation of the Dy:PbGa(2)S(4) laser directly pumped by the 1.7 μm laser diode. In the pulsed regime (pulse duration 5 ms; repetition rate 20 Hz), the maximum mean output power of 9.5 mW was obtained with the slope efficiency of 9.3% with respect to the absorbed pump power. The generated wavelength was 4.32 μm, and the laser beam cross section was approximately Gaussian on both axes. Stable CW laser generation was also successfully obtained with the maximum output power of 67 mW and the slope efficiency of 8%. Depopulation of the lower laser level by 1.7 μm pump radiation absorption followed by 1.3 μm upconversion fluorescence was demonstrated. These results show the possibility of construction of the compact diode-pumped solid-state pulsed or CW laser generating at 4.3 μm in the power level of tens mW operating at room temperature.

  10. Stability constants and thermodynamic parameters of trivalent gadolinium, yttrium, terbium, dysprosium and holmium complexes with 2-(p-sulphophenylazo) 1,8-dihydroxynaphthalene 3,6 disulphonic acid (trisodium salt)[SPADNS

    International Nuclear Information System (INIS)

    Dubey, S.N.; Nagpal, S.; Kalra, H.L.; Puri, D.M.

    1980-01-01

    The stepwise stability constants of Gd(III), Y(III), Tb(III), Dy(III) and Ho(III) complexes with SPADNS have been determined potentiometrically in aqueous solution using Bjerrum-Calvin technique as modified by Irving and Rossotti at different temperatures (20deg and 40deg) and 0.1 M ionic strength (NaClO 4 ). The trend in the stability of these metal complexes has been found to be: Ho(III) > Dy(III) > Tb(III) > Y(III) > Gd(III). The overall changes in ΔGdeg, ΔHdeg and ΔSdeg accompanying the complex formation have also been determined. (author)

  11. Stability constants and thermodynamic parameters of trivalent gadolinium, yttrium, terbium, dysprosium and holmium complexes with 2-(p-sulphophenylazo) 1,8-dihydroxynaphthalene 3,6 disulphonic acid (trisodium salt)(SPADNS)

    Energy Technology Data Exchange (ETDEWEB)

    Dubey, S.N.; Nagpal, S.; Kalra, H.L.; Puri, D.M. (Kurukshetra Univ. (India). Dept. of Chemistry)

    1980-10-01

    The stepwise stability constants of Gd(III), Y(III), Tb(III), Dy(III) and Ho(III) complexes with SPADNS have been determined potentiometrically in aqueous solution using Bjerrum-Calvin technique as modified by Irving and Rossotti at different temperatures (20deg and 40deg) and 0.1 M ionic strength (NaClO/sub 4/). The trend in the stability of these metal complexes has been found to be: Ho(III) > Dy(III) > Tb(III) > Y(III) > Gd(III). The overall changes in ..delta..Gdeg, ..delta..Hdeg and ..delta..Sdeg accompanying the complex formation have also been determined.

  12. Poly[(6-carboxypicolinato-κ3O2,N,O6(μ3-pyridine-2,6-dicarboxylato-κ5O2,N,O6:O2′:O6′dysprosium(III

    Directory of Open Access Journals (Sweden)

    Xu Li

    2009-11-01

    Full Text Available In the title complex, [Dy(C7H3NO4(C7H4NO4]n, one of the ligands is fully deprotonated while the second has lost only one H atom. Each DyIII ion is coordinated by six O atoms and two N atoms from two pyridine-2,6-dicarboxylate and two 6-carboxypicolinate ligands, displaying a bicapped trigonal-prismatic geometry. The average Dy—O bond distance is 2.40 Å, some 0.1Å longer than the corresponding Ho—O distance in the isotypic holmium complex. Adjacent DyIII ions are linked by the pyridine-2,6-dicarboxylate ligands, forming a layer in (100. These layers are further connected by π–π stacking interactions between neighboring pyridyl rings [centroid–centroid distance = 3.827 (3 Å] and C—H...O hydrogen-bonding interactions, assembling a three-dimensional supramolecular network. Within each layer, there are other π–π stacking interactions between neighboring pyridyl rings [centroid–centroid distance = 3.501 (2 Å] and O—H...O and C—H...O hydrogen-bonding interactions, which further stabilize the structure.

  13. Superconducting selenides intercalated with organic molecules: synthesis, crystal structure, electric and magnetic properties, superconducting properties, and phase separation in iron based-chalcogenides and hybrid organic-inorganic superconductors

    Science.gov (United States)

    Krzton-Maziopa, Anna; Pesko, Edyta; Puzniak, Roman

    2018-06-01

    Layered iron-based superconducting chalcogenides intercalated with molecular species are the subject of intensive studies, especially in the field of solid state chemistry and condensed matter physics, because of their intriguing chemistry and tunable electric and magnetic properties. Considerable progress in the research, revealing superconducting inorganic–organic hybrid materials with transition temperatures to superconducting state, T c, up to 46 K, has been brought in recent years. These novel materials are synthesized by low-temperature intercalation of molecular species, such as solvates of alkali metals and nitrogen-containing donor compounds, into layered FeSe-type structure. Both the chemical nature as well as orientation of organic molecules between the layers of inorganic host, play an important role in structural modifications and may be used for fine tuning of superconducting properties. Furthermore, a variety of donor species compatible with alkali metals, as well as the possibility of doping also in the host structure (either on Fe or Se sites), makes this system quite flexible and gives a vast array of new materials with tunable electric and magnetic properties. In this review, the main aspects of intercalation chemistry are discussed with a particular attention paid to the influence of the unique nature of intercalating species on the crystal structure and physical properties of the hybrid inorganic–organic materials. To get a full picture of these materials, a comprehensive description of the most effective chemical and electrochemical methods, utilized for synthesis of intercalated species, with critical evaluation of their strong and weak points, related to feasibility of synthesis, phase purity, crystal size and morphology of final products, is included as well.

  14. 壳寡糖模板法合成纳米硒化镍及其性质研究%Synthesis of nickel selenide nanocrystalines using Chitooligosaccharides as soft-template and their properties

    Institute of Scientific and Technical Information of China (English)

    朱文晶; 张胜义

    2012-01-01

    Ni0 85 Se Spherical nanocrystaline was synthesized by using Chitooligosaccharides as soft-template in a low-temperature hydrothermal process, the as-obtained product could then be transited to hollow spherical NiSe2 nanocrystaline at 500 t. Both products were characterized by transmission electron microscope (TEM) ,X-ray diffraction (XRD),ultraviolet (UV) analysis and photoluminescence (PL). The form mechanism and conditions affected were also discussed. In addition,the electrochemical properties of the two products were studied.%采用壳寡糖为软模板,通过低温水热法合成了球状纳米Ni0.85Se晶体,在500℃下灼烧50 min,转化为空心球状NiSe2晶体.通过透射电镜(TEM)、X射线衍射(XRD)、紫外-可见光谱(UV-vis)和荧光光谱(PL)等手段对产物进行了分析和表征,讨论了复合物的形成机理及反应条件对产物的影响.研究了产物的电化学性质.

  15. Experimental formation of Pb, Sn, Ge and Sb sulfides, selenides and chlorides in the presence of sal ammoniac: A contribution to the understanding of the mineral formation processes in coal wastes self-ignition

    Czech Academy of Sciences Publication Activity Database

    Laufek, F.; Veselovský, F.; Drábek, M.; Kříbek, B.; Klementová, Mariana

    176-177, May (2017), s. 1-7 ISSN 0166-5162 Institutional support: RVO:68378271 Keywords : coal wastes * metalloids * mineral formation * self-burning processes Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 4.783, year: 2016

  16. Improving the efficiency of copper indium gallium (Di-)selenide (CIGS) solar cells through integration of a moth-eye textured resist with a refractive index similar to aluminum doped zinc oxide

    NARCIS (Netherlands)

    Burghoorn, M.M.A.; Kniknie, B.J.; Deelen, J. van; Xu, M.; Vroon, Z.A.E.P.; Ee, R.J. van; Belt, R. van de; Buskens, P.J.P.

    2014-01-01

    Textured transparent conductors are widely used in thin-film silicon solar cells. They lower the reflectivity at interfaces between different layers in the cell and/or cause an increase in the path length of photons in the Si absorber layer, which both result in an increase in the number of absorbed

  17. Study on Magnetic Responsibility of Rare Earth Ferrite/Polyacrylamide Magnetic Microsphere

    Institute of Scientific and Technical Information of China (English)

    Zhang Ming; Wang Zhifeng; Zhang Hong; Dai Shaojun; Qiu Guanming; Okamoto Hiroshi

    2005-01-01

    In inverse microemulsion, rare earth ferrite/polyacrylamide magnetic microsphere were prepared and their magnetic responsibility were studied by magnetic balance. Results indicate that the magnetic responsibility of microsphere relates to magnetic moment of rare earth ion, and it can be improved by the addition of dysprosium ion of high magnetic moment. Dysprosium content has an effect on magnetic responsibility of dysprosium ferrite/polyacrylamide magnetic microsphere. The microsphere displays strong magnetic responsibility when the molar ratio of Dy3+/iron is 0.20.

  18. Electronic Structure of Cdse Nanowires Terminated With Gold ...

    African Journals Online (AJOL)

    Cadmium selenide nanowires in the wurtzite bulk phase, connected to gold electrodes are studied using local density approximation. The short wire is fully metalized by metal-induced gap states. For longer wires, a gap similar to that in bare cadmium selenide nanowires is observed near the center while sub-gap structure ...

  19. Zinc-enriched boutons in rat spinal cord

    DEFF Research Database (Denmark)

    Schrøder, H D; Danscher, G; Jo, S M

    2000-01-01

    The rat spinal cord reveals a complex pattern of zinc-enriched (ZEN) boutons. As a result of in vivo exposure to selenide ions, nanosized clusters of zinc selenide are created in places where zinc ions are present, including the zinc-containing synaptic vesicles of ZEN boutons. The clusters can...

  20. Characterization of Materials by Raman Scattering

    Science.gov (United States)

    Kozielski, M.

    2007-03-01

    The paper reports on the use of phonon spectra obtained with the Raman spectroscopy for characterization of different materials. The Raman scattering spectra obtained for zinc selenide crystals, mixed crystals zinc selenide admixtured with magnesium or beryllium, oxide crystals including strontium lanthanum gallate, molecular crystals of triammonium hydrogen diseleniate and a homologous series of polyoxyethylene glycols are analysed.

  1. 75 FR 39520 - Certain New Chemicals; Receipt and Status Information

    Science.gov (United States)

    2010-07-09

    ... of manufacturing copper indium metal selenide solar panel. The finished solar panel with copper indium metal selenide deposited on the substrate is encapsulated with the complete solar panel unit. The solar panel is sold to commercial entities only. P-10-0425 06/18/10 09/15/10 CBI (G) Component of (G...

  2. Synthesis and X-ray structure of the dysprosium(III complex derived from the ligand 5-chloro-1,3-diformyl-2-hydroxybenzene-bis-(2-hydroxybenzoylhydrazone [Dy2(C22H16ClN4O53](SCN 3.(H2O.(CH3OH

    Directory of Open Access Journals (Sweden)

    Aliou H. Barry

    2003-12-01

    Full Text Available The title compound [Dy2(C22H16ClN4O53](SCN 3.(H2O.(CH3OH has been synthesized and its crystal structure determined by single X-ray diffraction at room temperature. The two nine coordinated Dy(III are bound to three macromolecules ligand through the phenolic oxygens of the p-chlorophenol moieties, the nitrogen atoms and the carbonyl functions of the hydrazonic moieties. The phenolic oxygen atoms of the 2-hydroxybenzoyl groups are not bonded to the metal ions. In the bases of the coordination polyhedra the six Dy-N bonds are in the range 2.563(13-2.656(13 Å and the twelve Dy-O bonds are in the range 2.281(10-2.406(10 Å.

  3. Synthesis and magneto-structural studies on a new family of carbonato bridged 3d-4f complexes featuring a [CoLn(CO3)] (Ln = La, Gd, Tb, Dy and Ho) core: slow magnetic relaxation displayed by the cobalt(ii)-dysprosium(iii) analogue.

    Science.gov (United States)

    Majee, Mithun Chandra; Towsif Abtab, Sk Md; Mondal, Dhrubajyoti; Maity, Manoranjan; Weselski, Marek; Witwicki, Maciej; Bieńko, Alina; Antkowiak, Michał; Kamieniarz, Grzegorz; Chaudhury, Muktimoy

    2018-03-06

    A new family of [3 + 3] hexanuclear 3d-4f complexes [(μ 3 -CO 3 ){Co II Ln III L(μ 3 -OH)(OH 2 )} 3 ]-(ClO 4 )·mC 2 H 5 OH·nH 2 O (1-5) [Ln = La (1), Gd (2), Tb (3), Dy (4), and Ho (5)] have been prepared in moderate to high yields (62-78%) following a self-assembly reaction between the ligand 6,6',6''-(nitrilotris(methylene))tris-(2-methoxy-4-methylphenol) (H 3 L), Co(OAc) 2 ·4H 2 O and the lanthanide ion precursors in the mandatory presence of tetrabutylammonium hydroxide. During the reaction, atmospheric carbon dioxide is fixed in the product molecule as a bridging carbonato ligand which connects all the three lanthanide centers of this molecular assembly through a rare η 2 :η 2 :η 2 -μ 3 mode of bridging as revealed from X-ray crystallography. The metal centers in all these compounds, except the Gd III analogue (2), are coupled in antiferromagnetic manner while the nature of coupling in the CoGd complex is ferromagnetic. DFT calculations revealed that this ferromagnetic interaction occurs most likely by the Co II -Gd III superexchange, mediated via the bridging oxygen atoms. Only the Co II -Dy III compound (4) displayed a slow relaxation of the magnetization at a very low temperature as established by AC susceptibility measurements. The data provides an estimation of the activation energy U/k B = 9.2 K and the relaxation time constant τ 0 = 1.0 × 10 -7 s.

  4. XRD and 119Sn Moessbauer spectroscopy characterization of SnSe obtained from a simple chemical route

    International Nuclear Information System (INIS)

    Bernardes-Silva, Ana Claudia; Mesquita, A.F.; Moura de Neto, E.; Porto, A.O.; Ardisson, J.D.; Lima, G.M. de; Lameiras, F.S.

    2005-01-01

    Crystalline tin selenide semiconductor was synthesized by a chemical route. Selenium powder reacted with potassium boronhydride, giving a soluble selenium species potassium seleniumhydride. The reaction of potassium seleniumhydride with tin chloride produced crystalline tin selenide, which was characterized by X-ray diffraction, 119 Sn Moessbauer spectroscopy and scanning electronic microscopy. The material was thermally treated, in nitrogen flow, at 300 and 600 deg. C for 2 h and the particle size evolution was studied by X-ray diffraction. The X-ray diffraction and 119 Sn Moessbauer results showed that a mixture of tin oxides and orthorhombic tin selenide was obtained

  5. Photoelectric sensor output controlled by eyeball movements

    Science.gov (United States)

    1965-01-01

    The difference between the infrared absorption of the iris and infrared reflectivity of the eyeball controls the operation of a device consisting of an infrared source and amplifier, a cadmium selenide infrared sensor, and an infrared filter.

  6. Preparation of PbSe nanoparticles by electron beam irradiation ...

    Indian Academy of Sciences (India)

    Wintec

    Recently, the synthesis of binary metal selenides of group. IV has been investigated ... Pb(Ac)2 and Se powder reacted ... hol (PVA), potassium hydroxide (KOH), and isopropyl. *Author for ... 40 ml distilled water and reacted adequately. Subse-.

  7. Bulletin of Materials Science | News

    Indian Academy of Sciences (India)

    scale grain growth of two nanocrystalline materials, Pd81Zr19 and RuAl. ... Structural, optical and electrical properties of chemically deposited copper selenide films .... Effect of substitution of titanium by magnesium and niobium on structure and ...

  8. Integration of Solar Cells on Top of CMOS Chips - Part II: CIGS Solar Cells

    NARCIS (Netherlands)

    Lu, J.; Liu, Wei; Kovalgin, Alexeij Y.; Sun, Yun; Schmitz, Jurriaan

    2011-01-01

    We present the monolithic integration of deepsubmicrometer complementary metal–oxide–semiconductor (CMOS) microchips with copper indium gallium (di)selenide (CIGS) solar cells. Solar cells are manufactured directly on unpackaged CMOS chips. The microchips maintain comparable electronic performance,

  9. Growth Mechanism of Nanowires: Binary and Ternary Chalcogenides

    Science.gov (United States)

    Singh, N. B.; Coriell, S. R.; Su, Ching-Hua; Hopkins, R. H.; Arnold, B.; Choa, Fow-Sen; Cullum, Brian

    2016-01-01

    Semiconductor nanowires exhibit very exciting optical and electrical properties including high transparency and a several order of magnitude better photocurrent than thin film and bulk materials. We present here the mechanism of nanowire growth from the melt-liquid-vapor medium. We describe preliminary results of binary and ternary selenide materials in light of recent theories. Experiments were performed with lead selenide and thallium arsenic selenide systems which are multifunctional material and have been used for detectors, acousto-optical, nonlinear and radiation detection applications. We observed that small units of nanocubes and elongated nanoparticles arrange and rearrange at moderate melt undercooling to form the building block of a nanowire. Since we avoided the catalyst, we observed self-nucleation and uncontrolled growth of wires from different places. Growth of lead selenide nanowires was performed by physical vapor transport method and thallium arsenic selenide nanowire by vapor-liquid-solid (VLS) method. In some cases very long wires (>mm) are formed. To achieve this goal experiments were performed to create situation where nanowires grew on the surface of solid thallium arsenic selenide itself.

  10. Cermet electrode

    Science.gov (United States)

    Maskalick, Nicholas J.

    1988-08-30

    Disclosed is a cermet electrode consisting of metal particles of nickel, cobalt, iron, or alloys or mixtures thereof immobilized by zirconia stabilized in cubic form which contains discrete deposits of about 0.1 to about 5% by weight of praseodymium, dysprosium, terbium, or a mixture thereof. The solid oxide electrode can be made by covering a substrate with particles of nickel, cobalt, iron, or mixtures thereof, growing a stabilized zirconia solid oxide skeleton around the particles thereby immobilizing them, contacting the skeleton with a compound of praseodymium, dysprosium, terbium, or a mixture thereof, and heating the skeleton to a temperature of at least 500.degree. C. The electrode can also be made by preparing a slurry of nickel, cobalt, iron, or mixture and a compound of praseodymium, dysprosium, terbium, or a mixture thereof, depositing the slurry on a substrate, heating the slurry to dryness, and growing a stabilized zirconia skeleton around the metal particles.

  11. Chemical composition and microstructure of magnetically melt-textured Bi2Sr2Ca0.8Dy0.2Cu2O8-y

    International Nuclear Information System (INIS)

    Stassen, S.; Rulmont, A.; Krekels, T.; Ausloos, M.; Cloots, R.

    1996-01-01

    Dysprosium-doped Bi-based 2212 materials have been synthesized in the presence of a magnetic field, applied perpendicularly to the lateral face of a cylinder, by a melt-textured growth process. Thick (well oriented) layers of different chemical composition have been observed. A dysprosium-doped 2212 phase (the expected D phase) and a dysprosium-free bismuth-rich and strontium-deficient 2212 phase have been found. It is argued that the latter is a so-called M phase. Other impurity phases have been observed, connected with both 2212-type layers. A novel aspect of this work is the calcium solubility at the strontium site in the 2201 structure, and inversely the strontium solubility at the calcium site in the 8250 structure. (orig.)

  12. Influence of a solvent on thermodynamics of electrolytic dissociation of simple and complex rare earth salts

    Energy Technology Data Exchange (ETDEWEB)

    Gorodyskij, A.V.; Fialkov, Yu.Ya.; Chernyj, D.B. (AN Ukrainskoj SSR, Kiev. Inst. Obshchej i Neorganicheskoj Khimii; Kievskij Politekhnicheskij Inst. (Ukrainian SSR))

    1982-03-01

    Influence of the double mixed solvent on thermodynamic characteristics of ionic migration of lanthanum, neodymium, europium and dysprosium chlorides as well as their phenanthroline complexes is considered. Decrease of lambdasub(c) of simple and complex rare earth salts in the lanthanum, neodymium-europium-dysprosium series as explained by increase of solvation degree, associated with lanthanum compression. It is shown that increase of methanol or propanol content results in exothermicity decrease of the ionic migration process. The temperature constituents of enthalpy and entropy of dissociation of the simple and complex rare earth salts are presented.

  13. Steric structure and thermodynamic aspects of Dy3+ complexes with aminobenzoic acids in aqueous solutions

    International Nuclear Information System (INIS)

    Kondrashina, Yu.G.; Mustafina, A.R.; Vul'fson, S.G.

    1994-01-01

    Stability and structure of dysprosium(3) aminobenzoate complexes with molar ratios Dy:L 1:1 and 1:2 (HL-aminobenzoic acid) in aqueous solutions are determined on the basis of pH-metric and paramagnetic birefringence data. The increase of conjugation effect in the series of benzoic, meta- ortho-, and para-aminobenzoic acid results in the increase of stability of 1:1 and 1:2 complexes. Features of the structure and coordination of ligands in dysprosium complexes with meta-, ortho-, and para-aminobenzoic acid are considered. 11 refs.; 4 figs.; 2 tabs

  14. Faraday effect in γ-Dy2S3 and c-Dy2O3 paramagnetic crystals

    International Nuclear Information System (INIS)

    Shelykh, A.I.

    1987-01-01

    Studies of spectral and temperature dependences of Faraday effect in γ-Dy 2 S 3 and C-Dy 2 O 3 paramagnetic crystals are conducted. Paramagnetism of these crystals is brought about by Dy 3+ ions. Estimation of the effect of such factors as the value of paramagnetic ion concentration, width of the forbidden band, crystallochemical composition on magnetooptical effect in the considered compounds of dysprosium is carried out on the basis of the obtained experimental data and theoretical analysis. It is shown, that the Faraday effect in the considered compounds of dysprosium as well as the value of paramagnetic moment may be regarded rather accurately in free ion approximation

  15. The change of the state of an endohedral fullerene by encapsulation into SWCNT: a Raman spectroelectrochemical study of Dy3N@C80 peapods

    Czech Academy of Sciences Publication Activity Database

    Kalbáč, Martin; Kavan, Ladislav; Zukalová, Markéta; Yang, S.; Čech, J.; Roth, S.; Dunsch, L.

    2007-01-01

    Roč. 13, - (2007), s. 8811-8817 ISSN 0947-6539 R&D Projects: GA AV ČR KJB400400601; GA MŠk LC510 Institutional research plan: CEZ:AV0Z40400503 Keywords : dysprosium * electrochemistry * fullerenes * nanotubes Subject RIV: CG - Electrochemistry Impact factor: 5.330, year: 2007

  16. Preparation, Structure Characterization and Thermal Decomposition ...

    African Journals Online (AJOL)

    NJD

    Decomposition Process of the Dysprosium(III) m-Methylbenzoate 1 ... A dinuclear complex [Dy(m-MBA)3phen]2·H2O was prepared by the reaction of DyCl3·6H2O, m-methylbenzoic acid and .... ing rate of 10 °C min–1 are illustrated in Fig. 4.

  17. Critical resources in clean energy technologies and waste flows

    DEFF Research Database (Denmark)

    Habib, Komal

    is fraught with the risk of shifting the supply security problem from one type of non‐renewable resources (fossil fuels) to another type (metals), in particular the specialty metals such as rare earth elements e.g. neodymium and dysprosium. This PhD work presented an in‐depth analysis of potential resource...

  18. Regulation of the growth and photosynthesis of cherry tomato ...

    African Journals Online (AJOL)

    The growth and photosynthetic characteristics of cherry tomato seedlings were investigated under seven light irradiations such as dysprosium lamps (white light; control, C), red light emitting diodes (LEDs) (R), blue LEDs (B), orange LEDs (O), green LEDs (G), red and blue LEDs (RB) and red, blue and green LEDs (RBG) ...

  19. Axial segregation in high intensity discharge lamps measured by laser absorption spectroscopy

    NARCIS (Netherlands)

    Flikweert, A.J.; Nimalasuriya, T.; Groothuis, C.H.J.M.; Kroesen, G.M.W.; Stoffels, W.W.

    2005-01-01

    High intensity discharge lamps have a high efficiency. These lamps contain rare-earth additives (in our case dysprosium iodide) which radiate very efficiently. A problem is color separation in the lamp because of axial segregation of the rare-earth additives, caused by diffusion and convection. Here

  20. Axial segregation in high intensity discharge lamps measured by laser absorption spectroscopy

    NARCIS (Netherlands)

    Stoffels, W.W.; Flikweert, A.J.; Nimalasuriya, T.; Groothuis, C.H.J.M.; Haverlag, M.; Kroesen, G.M.W.

    2005-01-01

    HID lamps containing rare earth additives (in our case dysprosium) show color separation because of axial segregation, caused by diffusion and convection. Two-dimensional atomic Dy density profiles are measured by means of laser absorption spectroscopy. The radially resolved atomic density

  1. Test plan for air monitoring during the Cryogenic Retrieval Demonstration

    International Nuclear Information System (INIS)

    Yokuda, E.

    1992-06-01

    This report presents a test plan for air monitoring during the Cryogenic Retrieval Demonstration (CRD). Air monitors will be used to sample for the tracer elements neodymium, terbium, and ytterbium, and dysprosium. The results from this air monitoring will be used to determine if the CRD is successful in controlling dust and minimizing contamination. Procedures and equipment specifications for the test are included

  2. Material flow analysis of NdFeB magnets for Denmark: a comprehensive waste flow sampling and analysis approach.

    Science.gov (United States)

    Habib, Komal; Schibye, Peter Klausen; Vestbø, Andreas Peter; Dall, Ole; Wenzel, Henrik

    2014-10-21

    Neodymium-iron-boron (NdFeB) magnets have become highly desirable for modern hi-tech applications. These magnets, in general, contain two key rare earth elements (REEs), i.e., neodymium (Nd) and dysprosium (Dy), which are responsible for the very high strength of these magnets, allowing for considerable size and weight reduction in modern applications. This study aims to explore the current and future potential of a secondary supply of neodymium and dysprosium from recycling of NdFeB magnets. For this purpose, material flow analysis (MFA) has been carried out to perform the detailed mapping of stocks and flows of NdFeB magnets in Denmark. A novel element of this study is the value added to the traditionally practiced MFAs at national and/or global levels by complementing them with a comprehensive sampling and elemental analysis of NdFeB magnets, taken out from a sample of 157 different products representing 18 various product types. The results show that the current amount of neodymium and dysprosium in NdFeB magnets present in the Danish waste stream is only 3 and 0.2 Mg, respectively. However, this number is estimated to increase to 175 Mg of neodymium and 11.4 Mg of dysprosium by 2035. Nevertheless, efficient recovery of these elements from a very diverse electronic waste stream remains a logistic and economic challenge.

  3. Scanning Electron Microscope-Cathodoluminescence Analysis of Rare-Earth Elements in Magnets.

    Science.gov (United States)

    Imashuku, Susumu; Wagatsuma, Kazuaki; Kawai, Jun

    2016-02-01

    Scanning electron microscope-cathodoluminescence (SEM-CL) analysis was performed for neodymium-iron-boron (NdFeB) and samarium-cobalt (Sm-Co) magnets to analyze the rare-earth elements present in the magnets. We examined the advantages of SEM-CL analysis over conventional analytical methods such as SEM-energy-dispersive X-ray (EDX) spectroscopy and SEM-wavelength-dispersive X-ray (WDX) spectroscopy for elemental analysis of rare-earth elements in NdFeB magnets. Luminescence spectra of chloride compounds of elements in the magnets were measured by the SEM-CL method. Chloride compounds were obtained by the dropwise addition of hydrochloric acid on the magnets followed by drying in vacuum. Neodymium, praseodymium, terbium, and dysprosium were separately detected in the NdFeB magnets, and samarium was detected in the Sm-Co magnet by the SEM-CL method. In contrast, it was difficult to distinguish terbium and dysprosium in the NdFeB magnet with a dysprosium concentration of 1.05 wt% by conventional SEM-EDX analysis. Terbium with a concentration of 0.02 wt% in an NdFeB magnet was detected by SEM-CL analysis, but not by conventional SEM-WDX analysis. SEM-CL analysis is advantageous over conventional SEM-EDX and SEM-WDX analyses for detecting trace rare-earth elements in NdFeB magnets, particularly dysprosium and terbium.

  4. Accumulation of weak optical signals and spectral memory in InSe single crystals

    International Nuclear Information System (INIS)

    Abdinov, A.Shj.; Babaeva, R.F.

    1995-01-01

    Dysprosium alloying effect on the electron and physico-chemical properties of InSe monocrystals is studied. Accumulation of low light signals and spectral or color memory is shown to be observed under certain conditions (temperature, content of admitted impurity, wave length and light intensity)

  5. Tuning the activity of Pt alloy electrocatalysts by means of the lanthanide contraction

    DEFF Research Database (Denmark)

    Escribano, Maria Escudero; Malacrida, Paolo; Hansen, Martin Hangaard

    2016-01-01

    is lanthanum, cerium, samarium, gadolinium, terbium, dysprosium, thulium, or calcium. The materials are among the most active polycrystalline Pt-based catalysts reported, presenting activity enhancement by a factor of 3 to 6 over Pt. The active phase consists of a Pt overlayer formed by acid leaching. The ORR...

  6. Influence of organic component on geometry and stability of the Dy(3) complexes with benzoic and aminobenzoic acids in water-80 vol.% DMSO(DMFA) mixtures

    International Nuclear Information System (INIS)

    Kondrashina, Yu.G.; Mustafina, A.R.; Devyatov, F.V.; Vul'fson, S.G.; Kazanskij Gosudarstvennyj Univ., Kazan

    1995-01-01

    Data of pH-metric and magnetooptical analyses were used to evaluate stability and structure of benzoate and aminobenzoate dysprosium (3) complexes in water and water - 80 vol.% DMSO (DMFA) mixtures. Factors, dictating change of complex structure and stability when passing from water to organic water solvents, are discussed. 19 refs.; 2 figs.; 1 tab

  7. Thermal characterization of (U, Dy)O2 pellets

    International Nuclear Information System (INIS)

    Pelloni, M; Bianchi, L; Pablovich, M.E; Kaufmann, F; Kempf, R

    2012-01-01

    The thermal diffusivity of (U,Dy)O 2 pellets were determined in the temperature range 250 K to 1600 K measured by the laser flash method. The dependence of thermal with temperature and dysprosium content was studied and found in good agreement with physical models available (author)

  8. Material Flow Analysis of NdFeB magnets for Denmark: A comprehensive waste flow sampling and analysis approach

    DEFF Research Database (Denmark)

    Habib, Komal; Schibye, Peter Klausen; Vestbø, Andreas Peter

    2014-01-01

    for considerable size and weight reduction in modern applications. This study aims to explore the current and future potential of secondary supply of neodymium and dysprosium from recycling of NdFeB magnets. For this purpose, Material Flow Analysis (MFA) has been carried out to perform the detailed mapping...

  9. Field dosimetry on sterilization area of medical-hospitable materials

    International Nuclear Information System (INIS)

    Mariano, C.S.T.P.; Campos, L.L.

    1992-01-01

    The calcium sulfate doped with dysprosium, used in high dose dosimetry by electron paramagnetic resonance (EPR), is studied on field dosimetry for medical-hospitable materials sterilization. The calibration curves of EPR signal in function of absorbed dose in air and the thermal decay of EPR signal at room temperature are also presented. (C.G.C)

  10. A Thermally Actuated Flux Pump for Energizing YBCO Pucks

    Science.gov (United States)

    2016-05-01

    a Hall sensor with an advertised active area of approximately 1.016 mm diameter supplied by Lakeshore was positioned in the centre of the YBCO as...top and the coldhead (green) along the bottom. The brown colour is the light green of the coldhead and the orange of the dysprosium centre

  11. Excited bands in even-even rare-earth nuclei

    International Nuclear Information System (INIS)

    Vargas, Carlos E.; Hirsch, Jorge G.

    2004-01-01

    The energetics of states belonging to normal parity bands in even-even dysprosium isotopes, and their B(E2) transition strengths, are studied using an extended pseudo-SU(3) shell model. States with pseudospin 1 are added to the standard pseudospin 0 space, allowing for a proper description of known excited normal parity bands

  12. Perovskite catalysts for oxidative coupling

    Science.gov (United States)

    Campbell, Kenneth D.

    1991-01-01

    Perovskites of the structure A.sub.2 B.sub.2 C.sub.3 O.sub.10 are useful as catalysts for the oxidative coupling of lower alkane to heavier hydrocarbons. A is alkali metal; B is lanthanide or lanthanum, cerium, neodymium, samarium, praseodymium, gadolinium or dysprosium; and C is titanium.

  13. Optical properties of CuSe thin films - band gap determination

    Directory of Open Access Journals (Sweden)

    Petrović Milica

    2017-01-01

    Full Text Available Copper selenide thin films of three different thicknesses have been prepared by vacuum evaporation method on a glass substrate at room temperature. The optical properties of the films were investigated by UV-VIS-NIR spectroscopy and photoluminescence spectroscopy. Surface morphology was investigated by field-emission scanning electron microscopy. Copper selenide exhibits both direct and indirect transitions. The band gap for direct transition is found to be ~2.7 eV and that for indirect transition it is ~1.70 eV. Photoluminescence spectra of copper selenide thin films have also been analyzed, which show emission peaks at 530, 550, and 760 nm. The latter corresponds to indirect transition in investigated material. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III45003

  14. Brodtkorbite, Cu.sub.2./sub.HgSe.sub.2./sub., from Příbram, Czech Republic: crystal structure and description

    Czech Academy of Sciences Publication Activity Database

    Sejkora, J.; Škácha, P.; Laufek, F.; Plášil, Jakub

    2017-01-01

    Roč. 29, May (2017), s. 663-672 ISSN 0935-1221 R&D Projects: GA MŠk LO1603 EU Projects: European Commission(XE) CZ.2.16/3.1.00/24510 Institutional support: RVO:68378271 Keywords : brodtkorbite * silver mercury selenide * selenide minerals * crystal structure * uranium deposit * Příbram * Czech Republic Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 1.362, year: 2016

  15. Příbramite, CuSbSe.sub.2./sub., the Se-analogue of chalcostibite, a new mineral from Příbram, Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Škácha, P.; Sejkora, J.; Plášil, Jakub

    2017-01-01

    Roč. 29, May (2017), s. 653-661 ISSN 0935-1221 R&D Projects: GA MŠk LO1603 EU Projects: European Commission(XE) CZ.2.16/3.1.00/24510 Institutional support: RVO:68378271 Keywords : příbramite * new mineral * Se-analogue of chalcostibite * copper antimony selenide * selenide minerals * crystal structure * uranium deposite * Příbram * Czech republic Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 1.362, year: 2016

  16. Ultrasound-promoted organocatalytic enamine–azide [3 + 2] cycloaddition reactions for the synthesis of ((arylselanylphenyl-1H-1,2,3-triazol-4-ylketones

    Directory of Open Access Journals (Sweden)

    Gabriel P. Costa

    2017-04-01

    Full Text Available The use of sonochemistry is described in the organocatalytic enamine–azide [3 + 2] cycloaddition between 1,3-diketones and aryl azidophenyl selenides. These sonochemically promoted reactions were found to be amenable to a range of 1,3-diketones or aryl azidophenyl selenides, providing an efficient access to new ((arylselanylphenyl-1H-1,2,3-triazol-4-ylketones in good to excellent yields and short reaction times. In addition, this protocol was extended to β-keto esters, β-keto amides and α-cyano ketones. Selanyltriazoyl carboxylates, carboxamides and carbonitriles were synthesized in high yields at short times of reaction under very mild reaction conditions.

  17. Effect of relativistic electron radiation on Se Zn monocrystal microembrittlement

    International Nuclear Information System (INIS)

    Mazilov, A.V.; Stratienko, V.A.; Migal', V.P.; Lugovskaya, E.I.

    2002-01-01

    The influence of 60 MeV electron irradiation (fluences between 10 9 and 10 16 el/sm 2 ) on the mikrobrittleness of n-type sphalerite-structure zinc selenide has been investigated.It was found that irradiation caused the crack lengths to increase under constant load.In the fluence range of 10 9 to 10 13 el/sm 2 , an increase was observed in the critical load, at which cracks were formed. It is shown that the mechanical properties of zinc selenide are dominantly influenced by the defect clusters, for the formation of which an energy over 400 eV is needed

  18. Solid-state framing camera with multiple time frames

    Energy Technology Data Exchange (ETDEWEB)

    Baker, K. L.; Stewart, R. E.; Steele, P. T.; Vernon, S. P.; Hsing, W. W.; Remington, B. A. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2013-10-07

    A high speed solid-state framing camera has been developed which can operate over a wide range of photon energies. This camera measures the two-dimensional spatial profile of the flux incident on a cadmium selenide semiconductor at multiple times. This multi-frame camera has been tested at 3.1 eV and 4.5 keV. The framing camera currently records two frames with a temporal separation between the frames of 5 ps but this separation can be varied between hundreds of femtoseconds up to nanoseconds and the number of frames can be increased by angularly multiplexing the probe beam onto the cadmium selenide semiconductor.

  19. Diagrams of the formation of In2S3 and In2Se3 films on vitroceramic upon precipitation, according to potentiometric titration

    Science.gov (United States)

    Tulenin, S. S.; Bakhteev, S. A.; Yusupov, R. A.; Maskaeva, L. N.; Markov, V. F.

    2013-10-01

    Boundary conditions and ranges of the formation of indium(III) sulfide and selenide upon precipitation by thiocarbamide and selenocarbamide are determined. Potentiometric titration of indium chloride (InCl3) in the concentration range of 0.0001 to 0.100 mol/L by a solution of sodium hydroxide is performed. It is found that the following pH ranges are optimal for In2S3 and In2Se3 film precipitation: from 3.0 to 4.5 and from 9.0 to 14.0. Indium selenide layers 100 to 300 nm thick are prepared on vitroceramic by hydrochemcial precipitation.

  20. Anisotropic formation and distribution of stacking faults in II-VI semiconductor nanorods.

    Science.gov (United States)

    Hughes, Steven M; Alivisatos, A Paul

    2013-01-09

    Nanocrystals of cadmium selenide exhibit a form of polytypism with stable forms in both the wurtzite and zinc blende crystal structures. As a result, wurtzite nanorods of cadmium selenide tend to form stacking faults of zinc blende along the c-axis. These faults were found to preferentially form during the growth of the (001) face, which accounts for 40% of the rod's total length. Since II-VI semiconductor nanorods lack inversion symmetry along the c-axis of the particle, the two ends of the nanorod may be identified by this anisotropic distribution of faults.