CdS_xTe_1_-_x ternary semiconductors band gaps calculation using ground state and GW approximations

International Nuclear Information System (INIS)

Kheloufi, Nawal; Bouzid, Abderrazak

2016-01-01

We present band gap calculations of zinc-blende ternary CdS_xTe_1_-_x semiconductors within the standard DFT and quasiparticle calculations employing pseudopotential method. The DFT, the local density approximation (LDA) and the Generalized Gradient Approximation (GGA) based calculations have given very poor results compared to experimental data. The quasiparticle calculations have been investigated via the one-shot GW approximation. The present paper discuses and confirms the effect of inclusion of the semicore states in the cadmium (Cd) pseudopotential. The obtained GW quasiparticle band gap using Cd"+"2"0 pseudopotential has been improved compared to the obtained results from the available pseudopotential without the treatment of semicore states. Our DFT and quasiparticle band gap results are discussed and compared to the available theoretical calculations and experimental data. - Graphical abstract: Band gaps improvement concerning the binary and ternary alloys using the GW approximation and Cd"2"0"+ pseudopotential with others levels of approximations (the LDA and GGA approximation employing the Cd"1"2"+ and the LDA within Cd"2"0"+ pseudopotential). - Highlights: • The direct Γ- Γ and indirect Γ- X and Γ- L bands gaps show a nonlinear behavior when S content is enhanced. • The quasiparticle band gap result for the investigated semiconductors is improved using the GW approximation. • All CdS_xTe_1_-_x compounds in all compositions range from 0 to 1 are direct band gap semiconductors.

Experimental study of the ternary Ag-Cu-In phase diagram

International Nuclear Information System (INIS)

Bahari, Zahra; Elgadi, Mohamed; Rivet, Jacques; Dugue, Jerome

2009-01-01

The phase diagram of the Ag-Cu-In system was investigated using powder X-ray diffraction (XRD), differential scanning calorimetry (DSC) and electron probe microanalysis (EPMA). Two isothermal sections (at 510 and 607 deg. C) and 15 isopletic sections were studied. The results showed seven ternary peritectics, one ternary eutectic and one ternary metatectic. A complete reaction scheme was constructed, the valleys were drawn and the liquidus surfaces were derived from DSC data in the entire composition range.

Experimental study of the ternary Ag-Cu-In phase diagram

Energy Technology Data Exchange (ETDEWEB)

Bahari, Zahra [Laboratoire de chimie physique et minerale, Faculte des sciences pharmaceutiques et biologiques, Universite Paris Descartes, avenue de l' Observatoire, 75006 Paris (France); Laboratoire de chimie du solide mineral (LCSM), Faculte des sciences, Universite Mohamed 1er, Route Sidi Maafa, B.P. 524, Oujda, Maroc (Morocco); Elgadi, Mohamed [Laboratoire de chimie du solide mineral (LCSM), Faculte des sciences, Universite Mohamed 1er, Route Sidi Maafa, B.P. 524, Oujda, Maroc (Morocco); Rivet, Jacques [Laboratoire de chimie physique et minerale, Faculte des sciences pharmaceutiques et biologiques, Universite Paris Descartes, avenue de l' Observatoire, 75006 Paris (France); Dugue, Jerome [Laboratoire de chimie physique et minerale, Faculte des sciences pharmaceutiques et biologiques, Universite Paris Descartes, avenue de l' Observatoire, 75006 Paris (France)], E-mail: jerome.dugue@univ-paris5.fr

2009-05-27

The phase diagram of the Ag-Cu-In system was investigated using powder X-ray diffraction (XRD), differential scanning calorimetry (DSC) and electron probe microanalysis (EPMA). Two isothermal sections (at 510 and 607 deg. C) and 15 isopletic sections were studied. The results showed seven ternary peritectics, one ternary eutectic and one ternary metatectic. A complete reaction scheme was constructed, the valleys were drawn and the liquidus surfaces were derived from DSC data in the entire composition range.

Origin of the Distinct Diffusion Behaviors of Cu and Ag in Covalent and Ionic Semiconductors.

Science.gov (United States)

Deng, Hui-Xiong; Luo, Jun-Wei; Li, Shu-Shen; Wei, Su-Huai

2016-10-14

It is well known that Cu diffuses faster than Ag in covalent semiconductors such as Si, which has prevented the replacement of Ag by Cu as a contact material in Si solar cells for reducing the cost. Surprisingly, in more ionic materials such as CdTe, Ag diffuses faster than Cu despite that it is larger than Cu, which has prevented the replacement of Cu by Ag in CdTe solar cells to improve the performance. But, so far, the mechanisms behind these distinct diffusion behaviors of Cu and Ag in covalent and ionic semiconductors have not been addressed. Here we reveal the underlying mechanisms by combining the first-principles calculations and group theory analysis. We find that the symmetry controlled s-d coupling plays a critical role in determining the diffusion behaviors. The s-d coupling is absent in pure covalent semiconductors but increases with the ionicity of the zinc blende semiconductors, and is larger for Cu than for Ag, owing to its higher d orbital energy. In conjunction with Coulomb interaction and strain energy, the s-d coupling is able to explain all the diffusion behaviors from Cu to Ag and from covalent to ionic hosts. This in-depth understanding enables us to engineer the diffusion of impurities in various semiconductors.

CdS{sub x}Te{sub 1-x} ternary semiconductors band gaps calculation using ground state and GW approximations

Energy Technology Data Exchange (ETDEWEB)

Kheloufi, Nawal; Bouzid, Abderrazak, E-mail: a_bouzid34@hotmail.com

2016-06-25

We present band gap calculations of zinc-blende ternary CdS{sub x}Te{sub 1-x} semiconductors within the standard DFT and quasiparticle calculations employing pseudopotential method. The DFT, the local density approximation (LDA) and the Generalized Gradient Approximation (GGA) based calculations have given very poor results compared to experimental data. The quasiparticle calculations have been investigated via the one-shot GW approximation. The present paper discuses and confirms the effect of inclusion of the semicore states in the cadmium (Cd) pseudopotential. The obtained GW quasiparticle band gap using Cd{sup +20} pseudopotential has been improved compared to the obtained results from the available pseudopotential without the treatment of semicore states. Our DFT and quasiparticle band gap results are discussed and compared to the available theoretical calculations and experimental data. - Graphical abstract: Band gaps improvement concerning the binary and ternary alloys using the GW approximation and Cd{sup 20+} pseudopotential with others levels of approximations (the LDA and GGA approximation employing the Cd{sup 12+} and the LDA within Cd{sup 20+} pseudopotential). - Highlights: • The direct Γ- Γ and indirect Γ- X and Γ- L bands gaps show a nonlinear behavior when S content is enhanced. • The quasiparticle band gap result for the investigated semiconductors is improved using the GW approximation. • All CdS{sub x}Te{sub 1-x} compounds in all compositions range from 0 to 1 are direct band gap semiconductors.

A facile fabrication of plasmonic g-C{sub 3}N{sub 4}/Ag{sub 2}WO{sub 4}/Ag ternary heterojunction visible-light photocatalyst

Energy Technology Data Exchange (ETDEWEB)

Dai, Kai, E-mail: daikai940@chnu.edu.cn [College of Physics and Electronic Information, Huaibei Normal University, Huaibei, 235000 (China); Lv, Jiali [College of Physics and Electronic Information, Huaibei Normal University, Huaibei, 235000 (China); Lu, Luhua, E-mail: lhlu@cug.edu.cn [Faculty of Material Science and Chemical Engineering, China University of Geosciences, Wuhan, 430074 (China); Liang, Changhao [College of Physics and Electronic Information, Huaibei Normal University, Huaibei, 235000 (China); Key Laboratory of Materials Physics and Anhui Key Laboratory of Nanomaterials and Nanotechnology, Institute of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031 (China); Geng, Lei; Zhu, Guangping [College of Physics and Electronic Information, Huaibei Normal University, Huaibei, 235000 (China)

2016-07-01

It's important to reduce recombination of electrons and holes and enhance charge transfer through fine controlled interfacial structure. In this work, novel graphitic-C{sub 3}N{sub 4} (g-C{sub 3}N{sub 4})/Ag{sub 2}WO{sub 4}/Ag ternary photocatalyst has been synthesized by deposition of Ag{sub 2}WO{sub 4} onto g-C{sub 3}N{sub 4} template and followed by sun light reduction of Ag{sub 2}WO{sub 4} into Ag{sub 2}WO{sub 4}/Ag. As-prepared g-C{sub 3}N{sub 4}/Ag{sub 2}WO{sub 4}/Ag presented significantly enhanced photocatalytic performance in degrading methylene blue (MB) under 410 nm LED light irradiation. Metallic Ag{sup 0} is used as plasmonic hot spots to generate high energy charge carriers. Optimal g-C{sub 3}N{sub 4} content has been confirmed to be 40 wt%, corresponding to apparent pseudo-first-order rate constant kapp of 0.0298 min{sup −1}, which is 3.3 times and 37.3 times more than that of pure g-C{sub 3}N{sub 4} and Ag{sub 2}WO{sub 4}, respectively. This novel ternary g-C{sub 3}N{sub 4}/Ag{sub 2}WO{sub 4}/Ag structure material is an ideal candidate in environmental treatment and purifying applications. - Graphical abstract: A high efficient plasmonic graphitic-C{sub 3}N{sub 4}/Ag{sub 2}WO{sub 4}/Ag ternary nanocomposite photocatalyst was synthesized. - Highlights: • g-C{sub 3}N{sub 4}/Ag{sub 2}WO{sub 4}/Ag ternary nanocomposite photocatalyst was prepared. • g-C{sub 3}N{sub 4}/Ag{sub 2}WO{sub 4}/Ag showed high photocatalytic activity. • g-C{sub 3}N{sub 4}/Ag{sub 2}WO{sub 4}/Ag showed long reusable life.

Experimental study of the phase equilibria in the Mg–Zn–Ag ternary system at 300 °C

Energy Technology Data Exchange (ETDEWEB)

Wang, Jian, E-mail: jian.wang@polymtl.ca [Center for Research in Computational Thermochemistry (CRCT), Department of Chemical Engineering, École Polytechnique, Montréal, Québec H3C 3A7 (Canada); Zhang, Yi-Nan [Department of Mechanical Engineering, Concordia University, 1455 De Maisonneuve Blvd. West, Montreal, Quebec H3G 1M8 (Canada); Hudon, Pierre; Jung, In-Ho [Department of Mining and Materials Engineering, McGill University, 3610 University Street, Montreal, Quebec H3A 0C5 (Canada); Medraj, Mamoun [Department of Mechanical Engineering, Concordia University, 1455 De Maisonneuve Blvd. West, Montreal, Quebec H3G 1M8 (Canada); Department of Mechanical and Materials Engineering, Masdar Institute, Masdar City, P.O. Box 54224, Abu Dhabi (United Arab Emirates); Chartrand, Patrice [Center for Research in Computational Thermochemistry (CRCT), Department of Chemical Engineering, École Polytechnique, Montréal, Québec H3C 3A7 (Canada)

2015-08-05

Highlights: • The phase equilibria of Mg–Zn–Ag system at 300 °C were determined. • A bcc continuous ternary solid solution forms between MgAg (bcc-B2) and AgZn (bcc-A2) was determined. • The extended solid solubilities of the sub-binary compounds were also determined. - Abstract: The phase equilibria in the Mg–Zn–Ag ternary system at 300 °C were investigated using three diffusion couples and 35 key samples. Scanning electron microscopy (SEM) equipped with energy-dispersive spectroscope (EDS) and X-ray diffraction (XRD) techniques were used for homogeneity ranges and crystal structure determination. Large solid solubility limits, due to substitution among Mg, Zn and Ag atoms in Mg{sub 3}Ag and MgZn{sub 2} phases, were observed in the present work. Solid solubility limits of Ag and Zn in the hcp (Mg) phase were found to be less than 1 at.%. The extended solid solubilities of the Mg{sub 12}Zn{sub 13}, Mg{sub 2}Zn{sub 3}, MgZn{sub 2} (C14), Mg{sub 2}Zn{sub 11}, Ag{sub 5}Zn{sub 8} and hcp (AgZn{sub 3}) sub-binary compounds were also determined in the Mg–Zn–Ag ternary system. In addition, a bcc continuous ternary solid solution forms between MgAg (bcc-B2) and AgZn (bcc-A2) at 300 °C.

Study of the pseudo-ternary Ag2SAs2S3HgI2 vitreous system

Science.gov (United States)

Boidin, R.; Le Coq, D.; Cuisset, A.; Hindle, F.; Brubach, J.-B.; Michel, K.; Bychkov, E.

2013-03-01

Chalcogenide alloys in the Ag2SAs2S3HgI2 pseudo-ternary system were synthesized and their vitreous nature was verified by X-ray diffraction. The glass transition and crystallization temperatures (Tg and Tc), the density (d), and the total electrical conductivity (σ) were measured for all samples of three series, A, B, and C corresponding to (Ag2S)50-x/2(As2S3)50-x/2(HgI2)x, (Ag2S)y(As2S3)80-y(HgI2)20 and (Ag2S)z(As2S3)50(HgI2)50-z, respectively. The maximum of Tg was approximately 160 °C for glasses with low HgI2 content whereas the maximum of density (5.75 g cm-3) was obtained for the sample in the B-series with the highest Ag2S concentration (z=60 mol%). This composition also possesses the highest conductivity at 298 K (σ298 K≈10-3 S cm-1). Unexpectedly the conductivity of the A-series samples was observed to decrease as a function of the Ag2S content. The far-infrared transmission in the 100-600 cm-1 window range (3.3-18.2 THz, 100-16.6 μm) was also given for a few glass compositions highlighting the strong influence of the HgI2 content.

Physical Properties Of Some Pd-Au-Ag Ternary Alloys: A Md Study

International Nuclear Information System (INIS)

Aydin, G.

2010-01-01

Mechanical properties of palladium (Pd), gold (Au) and silver (Ag) and their ternary alloys in the following concentrations (Au 5 0Ag 2 5Pd 2 5, Au 4 0Ag 2 0Pd 4 0) are studied by using by using molecular dynamics with Quantum Sutton-Chen (Q-SC) potential. Cell constants, densities, enthalpies, elastic constants and heat capacities are investigated. Calculations are performed in the solid phase. Rafii-Tabar combination rules are used and it is showed that these combination rules are valid for ternary alloys also. Additionally, temperature dependence of mechanical properties of alloys are investigated.

Photocatalytic oxidation removal of Hg"0 using ternary Ag/AgI-Ag_2CO_3 hybrids in wet scrubbing process under fluorescent light

International Nuclear Information System (INIS)

Zhang, Anchao; Zhang, Lixiang; Chen, Xiaozhuan; Zhu, Qifeng; Liu, Zhichao; Xiang, Jun

2017-01-01

Highlights: • Ag/AgI-Ag_2CO_3 hybrids were employed for Hg"0 removal under fluorescent light. • Superoxide radical (·O_2"−) played a key role in Hg"0 removal. • NO exhibited a significant effect on Hg"0 removal in comparison to SO_2. • The mechanism for enhanced Hg"0 removal over Ag/AgI-Ag_2CO_3 was proposed. - Abstract: A series of ternary Ag/AgI-Ag_2CO_3 photocatalysts synthesized using a facile coprecipitation method were employed to investigate their performances of Hg"0 removal in a wet scrubbing reactor. The hybrids were characterized by N_2 adsorption-desorption, XRD, SEM-EDS, HRTEM, XPS, DRS and ESR. The photocatalytic activities of Hg"0 removal were evaluated under fluorescent light. The results showed that AgI content, fluorescent light irradiation, reaction temperature all showed significant influences on Hg"0 removal. NO exhibited significant effect on Hg"0 removal in comparison to SO_2. Among these ternary Ag/AgI-Ag_2CO_3 hybrids, Ag/AgI(0.1)-Ag_2CO_3 showed the highest Hg"0 removal efficiency, which could be ascribed to the effective separation of photogenerated electron-hole pairs between AgI and Ag_2CO_3 and the surface plasmon resonance (SPR) effect in the visible region by metallic silver nanoparticles (Ag"0 NPs). The trapping studies of reactive radicals showed that the superoxide radicals (·O_2"−) may play a key role in Hg"0 removal under fluorescent light. According to the experimental and characterization results, a possible photocatalytic oxidation mechanism for enhanced Hg"0 removal over Ag/AgI(0.1)-Ag_2CO_3 hybrid under fluorescent light was proposed.

Bond charges and electronic charge transfer in ternary semiconductors

International Nuclear Information System (INIS)

Pietsch, U.

1986-01-01

By means of a simple molecule-theoretic model of 'linear superposition of two-electron molecules' the bond charges between nearest neighbours and the effective charges of ions are calculated for ternary zinc-blende structure alloys as well as chalcopyrite semiconductors. Taking into account both, the charge transfer among the ions caused by the differences of electronegativities of atoms used and between the bonds created by the internal stress of the lattice a nearly unvaried averaged bond charge amount of the alloy is found, but rather dramatically changed local bond charge parameters in comparison with the respective values of binary compounds used. This fact should influence the noncentral force interaction in such semiconductors. (author)

Synthesis and Characterization of Novel Ternary and Quaternary Alkali Metal Thiophosphates

KAUST Repository

Alahmary, Fatimah S.

2014-05-01

The ongoing development of nonlinear optical (NLO) crystals such as coherent mid-IR sources focuses on various classes of materials such as ternary and quaternary metal chalcophosphates. In case of thiophosphates, the connection between PS4-tetrahedral building blocks and metals gives rise to a broad structural variety where approximately one third of all known ternary (A/P/S) and quaternary (A/M/P/S) (A = alkali metal, M = metal) structures are acentric and potential nonlinear optical materials. The molten alkali metal polychalcophosphate fluxes are a well-established method for the synthesis of new ternary and quaternary thiophosphate and selenophosphate compounds. It has been a wide field of study and investigation through the last two decades. Here, the flux method is used for the synthesis of new quaternary phases containing Rb, Ag, P and S. Four new alkali metal thiophosphates, Rb4P2S10, RbAg5(PS4), Rb2AgPS4 and Rb3Ag9(PS4)4, have been synthesized successfully from high purity elements and binary starting materials. The new compounds were characterized by single crystal and powder X-ray diffraction, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), ultraviolet-visible (UV-VIS), Raman spectroscopy, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). These compounds show interesting structural variety and physical properties. The crystal structures feature 3D anionic framework built up of PS4 tetrahedral units and charge balanced by Ag and alkali metal cations. All prepared compounds are semiconductors with band gap between 2.3 eV to 2.6 eV and most of them are thermally stable up to 600ºC.

Thermodynamics and phase equilibria of ternary systems relevant to contact materials for compound semiconductors

International Nuclear Information System (INIS)

Ipser, H.; Richter, K.; Micke, K.

1997-01-01

In order to investigate the stability of ohmic contacts to compound semiconductors, it is necessary to know the phase equilibria in the corresponding multi-component systems. We are currently studying the phase equilibria and thermophysical properties of several ternary systems which are of interest in view of the use of nickel, palladium and platinum as contact materials for GaSb and InSb compound semiconductors: Ga-Ni-Sb, In-Ni-Sb, Ga-Pd-Sb and Ga-Pt-Sb. Phase equilibria are investigated by thermal analyses, X-ray powder diffraction methods as well as electron microprobe analysis. Thermodynamic properties are derived from vapour pressure measurements using an isopiestic method. It is planned to combine all information on phase equilibria and thermochemistry for the ternary and the limiting binary systems to perform an optimization of the ternary systems by computer calculations using standard software. (author)

Thermal analysis and prediction of phase equilibria in ternary Pb-Zn-Ag system

Directory of Open Access Journals (Sweden)

Živković D.

2011-01-01

Full Text Available Ternary Pb-Zn-Ag system is typical for some physicochemical processes going on in refining phase in the extractive metallurgy of lead. Therefore, investigation of mentioned system is important from both theoretical and practical research of the phenomena occurring during the lead desilverizing process. The results of experimental investigation using differential thermal analysis (DTA and thermodynamic calculation of phase equilibria in Pb-Zn-Ag system according to CALPHAD method, in the sections with Zn:Ag mass ratio equal to 90:10, 70:30 and 50:50, are presented in this paper.

Ternary rare earth sulfide CaCe2S4: Synthesis and characterization of stability, structure, and photoelectrochemical properties in aqueous media

Science.gov (United States)

Sotelo, Paola; Orr, Melissa; Galante, Miguel Tayar; Hossain, Mohammad Kabir; Firouzan, Farinaz; Vali, Abbas; Li, Jun; Subramanian, Mas; Longo, Claudia; Rajeshwar, Krishnan; Macaluso, Robin T.

2018-06-01

A red-orange rare earth ternary chalcogenide, CaCe2S4, was prepared in powder form by solid-state synthesis. The structural details of this compound were determined by powder X-ray diffraction. The optical band gap of CaCe2S4 was determined by diffuse reflectance spectroscopy (DRS) to be 2.1 eV, consistent with the observed red-orange color. Quantitative colorimetry measurements also support the observed color and band gap of CaCe2S4. Both direct and indirect optical transitions were gleaned from Tauc analyses of the DRS data. Photoelectrochemistry experiments on CaCe2S4 films showed n-type semiconductor behavior. Analyses of these data via the Butler-Gärtner model afforded a flat-band potential of - 0.33 V (vs. Ag/AgCl/KCl 4 M) in pH 9 aqueous sulfite electrolyte. The potential and limitations of this material for solar water splitting and photocatalytic environmental remediation (e.g., dye photodegradation) are finally presented against the backdrop of its photoelectrochemical stability and surface hole transfer kinetics in aqueous electrolytes.

Photocatalytic oxidation removal of Hg{sup 0} using ternary Ag/AgI-Ag{sub 2}CO{sub 3} hybrids in wet scrubbing process under fluorescent light

Energy Technology Data Exchange (ETDEWEB)

Zhang, Anchao, E-mail: aczhang@qq.com [School of Mechanical and Power Engineering, Henan Polytechnic University, Jiaozuo, 454000 (China); Zhang, Lixiang; Chen, Xiaozhuan; Zhu, Qifeng; Liu, Zhichao [School of Mechanical and Power Engineering, Henan Polytechnic University, Jiaozuo, 454000 (China); Xiang, Jun, E-mail: xiangjun@mail.hust.edu.cn [State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan, 430074 (China)

2017-01-15

Highlights: • Ag/AgI-Ag{sub 2}CO{sub 3} hybrids were employed for Hg{sup 0} removal under fluorescent light. • Superoxide radical (·O{sub 2}{sup −}) played a key role in Hg{sup 0} removal. • NO exhibited a significant effect on Hg{sup 0} removal in comparison to SO{sub 2}. • The mechanism for enhanced Hg{sup 0} removal over Ag/AgI-Ag{sub 2}CO{sub 3} was proposed. - Abstract: A series of ternary Ag/AgI-Ag{sub 2}CO{sub 3} photocatalysts synthesized using a facile coprecipitation method were employed to investigate their performances of Hg{sup 0} removal in a wet scrubbing reactor. The hybrids were characterized by N{sub 2} adsorption-desorption, XRD, SEM-EDS, HRTEM, XPS, DRS and ESR. The photocatalytic activities of Hg{sup 0} removal were evaluated under fluorescent light. The results showed that AgI content, fluorescent light irradiation, reaction temperature all showed significant influences on Hg{sup 0} removal. NO exhibited significant effect on Hg{sup 0} removal in comparison to SO{sub 2}. Among these ternary Ag/AgI-Ag{sub 2}CO{sub 3} hybrids, Ag/AgI(0.1)-Ag{sub 2}CO{sub 3} showed the highest Hg{sup 0} removal efficiency, which could be ascribed to the effective separation of photogenerated electron-hole pairs between AgI and Ag{sub 2}CO{sub 3} and the surface plasmon resonance (SPR) effect in the visible region by metallic silver nanoparticles (Ag{sup 0} NPs). The trapping studies of reactive radicals showed that the superoxide radicals (·O{sub 2}{sup −}) may play a key role in Hg{sup 0} removal under fluorescent light. According to the experimental and characterization results, a possible photocatalytic oxidation mechanism for enhanced Hg{sup 0} removal over Ag/AgI(0.1)-Ag{sub 2}CO{sub 3} hybrid under fluorescent light was proposed.

Microstructural evolution of ternary Ag33Cu42Ge25 eutectic alloy inside ultrasonic field

Directory of Open Access Journals (Sweden)

Wei Zhai

2014-12-01

Full Text Available Ultrasonic field with a frequency of 20 kHz is introduced into the solidification process of ternary Ag33Cu42Ge25 eutectic alloy from the sample bottom to its top. The ultrasound stimulates the nucleation of alloy melt and prevents its bulk undercooling. At low ultrasound power of 250 W, the primary ε2 phase in the whole alloy sample grows into non-faceted equiaxed grains, which differs to its faceted morphology of long strip under static condition. The pseudobinary (Ag+ε2 eutectic transits from dendrite shape grain composed of rod type eutectic to equiaxed chrysanthemus shape formed by lamellar structure. By contrast, the ultrasound produces no obvious variation in the morphology of ternary (Ag+Ge+ε2 eutectic except a coarsening effect. When ultrasound power rises to 500 W, divorced ternary (Ag+Ge+ε2 eutectic forms at the sample bottom. However, in the upper part, the ultrasonic energy weakens, and it only brings about prominent refining effect to primary ε2 phase. The microstructural evolution mechanism is investigated on the cavitation, acoustic streaming and acoustic attenuation.

On the ternary Ag – Cu – Ga system: Electromotive force measurement and thermodynamic modeling

International Nuclear Information System (INIS)

Gierlotka, Wojciech; Jendrzejczyk-Handzlik, Dominika; Fitzner, Krzysztof; Handzlik, Piotr

2015-01-01

The ternary silver–copper–gallium system found application as a solder material in jewel crafting and electronics, thus a phase diagram of this system seems to be important tool, which is necessary for a proper application of different alloys. The activity of gallium in liquid phase was determined by electromotive measurement technique and after that the equilibrium diagram of Ag – Cu – Ga was modeled based on available experimental data using Calphad approach. A set of Gibbs energies was found and used for calculation a phase diagram and thermodynamic properties of liquid phase. The experimental data was reproduced well by calculation. - Highlights: • For the first time activity of Ga in liquid Ag – Cu – Ga alloys was measured. • For the first time the ternary Ag – Cu – Ga system was thermodynamically modeled. • Modeled Ag – Cu – Ga system reproduces experimental data well

Synthesis and characterization of the ternary telluroargentate K4[Ag18Te11

KAUST Repository

Davaasuren, Bambar

2014-10-19

The ternary potassium telluroargentate(I), K4[Ag18Te11], was prepared by solvothermal synthesis in ethylenediamine at 160 °C. It crystallizes in the cubic space group Fm3¯ m (no. 225) with the cell parameter a = 18.6589(6) Å. The crystal structure can be described as a [Ag18Te11]4- three-dimensional anionic framework with the voids accommodating potassium cations. Chemical bonding analysis reveals polar covalent Ag-Te bonds and considerable Ag-Ag interactions, which support the complex anionic character of the structure. The compound is thermally stable up to 450 °C in an inert atmosphere.

One-pot, facile fabrication of a Ag3PO4-based ternary Z-scheme photocatalyst with excellent visible-light photoactivity and anti-photocorrosion performance

Science.gov (United States)

Xie, Mingyuan; Zhang, Tailiang

2018-04-01

Ag3PO4 can-not be widely used as an efficient photocatalyst in practical applications because of its susceptibility to photocorrosion. In this study, a novel, ternary Z-scheme photocatalytic system containing graphene oxide (GO), Ag3PO4 and SnS2 was fabricated by a one-pot, mild, in-situ precipitation method successfully. Using Rhodamine B (RhB) as the target of elimination, GO/Ag3PO4/SnS2 exhibited outstanding photocatalytic and anti-photocorrosion properties compared with those of Ag3PO4, Ag3PO4/SnS2 and GO/Ag3PO4. RhB was thoroughly degraded over the optimized GO/Ag3PO4/SnS2 nanocomposite after only 15 min under visible-light irradiation; this result is approximately 2.14, 3.33 and 5.83 times faster than that of GO/Ag3PO4, Ag3PO4/SnS2 and Ag3PO4, respectively. After three reuses, the photocatalytic activity of the ternary composite slightly decreased but remained 2.36, 4.08 and 12.70 times higher than those of the reused GO/Ag3PO4, Ag3PO4/SnS2 and Ag3PO4, respectively. In this system, the efficient separation and migration of the photoinduced current carriers in Ag3PO4 was realized through a double Z-scheme electron-transfer mechanism in which the GO nanosheets acted as the photocatalyst and electron mediator, thereby enhancing the photoactivity and stability of Ag3PO4. The present study provides a new perspective for enhancing photocatalytic and anti-photocorrosion performances in perishable photocatalysts for organic sewage and other environmental contamination treatments.

Ternary ZnO/AgI/Ag2CO3 nanocomposites: Novel visible-light-driven photocatalysts with excellent activity in degradation of different water pollutants

International Nuclear Information System (INIS)

Golzad-Nonakaran, Behrouz; Habibi-Yangjeh, Aziz

2016-01-01

ZnO/AgI/Ag 2 CO 3 nanocomposites with different Ag 2 CO 3 contents were fabricated by a facile ultrasonic-irradiation method. The resultant samples were fairly characterized using XRD, EDX, SEM, TEM, UV–vis DRS, FT-IR, and PL techniques to reveal their microstructure, purity, morphology, and spectroscopic properties. Photocatalytic activity of the prepared samples was investigated by photodegradation of four dye pollutants (rhodamine B, methyl orange, methylene blue, and fuchsine) under visible-light irradiation. The photocatalytic experiments in degradation of rhodamine B showed that the ternary ZnO/AgI/Ag 2 CO 3 (30%) nanocomposite has an enhanced activity nearly 19 and 14 times higher than those of the binary ZnO/Ag 2 CO 3 and ZnO/AgI photocatalysts, respectively. Based on the obtained results, the highly enhanced activity was attributed to generation of more electron-hole pairs under visible-light irradiation and separation of the photogenerated charge carriers due to formation of tandem n-n heterojunctions between counterparts of the nanocomposite. The active species trapping experiments were also examined and it was showed that superoxide ion radicals play a vital role in the photocatalytic degradation reaction. More importantly, the ternary photocatalyst demonstrated good photostability. - Highlights: • ZnO/AgI/Ag 2 CO 3 nanocomposites were fabricated by an ultrasonic-irradiation method. • The activity was investigated by photodegradation of four dyes under visible light. • ZnO/AgI/Ag 2 CO 3 (30%) nanocomposite has the best activity under visible light. • Activity is 19 and 14-folds higher than ZnO/Ag 2 CO 3 and ZnO/AgI in degradation of RhB.

Direct femtosecond observation of charge carrier recombination in ternary semiconductor nanocrystals: The effect of composition and shelling

KAUST Repository

Bose, Riya; Ahmed, Ghada H.; Alarousu, Erkki; Parida, Manas R.; Abdelhady, Ahmed L.; Bakr, Osman; Mohammed, Omar F.

2015-01-01

Heavy-metal free ternary semiconductor nanocrystals are emerging as key materials in photoactive applications. However, the relative abundance of intra-bandgap defect states and lack of understanding of their origins within this class

Stability of Naturally Relevant Ternary Phases in the Cu–Sn–S system in Contact with an Aqueous Solution

Directory of Open Access Journals (Sweden)

Andrea Giaccherini

2016-07-01

Full Text Available A relevant research effort is devoted to the synthesis and characterization of phases belonging to the ternary system Cu–Sn–S, mainly for their possible applications in semiconductor technology. Among all ternary phases, kuramite, Cu3SnS4, mohite, Cu2SnS3, and Cu4Sn7S16 have attracted the highest interest. Numerous studies were carried out claiming for the description of new phases in the ternary compositional field. In this study, we revise the existing literature on this ternary system, with a special focus on the phases stable in a temperature range at 25 °C. The only two ternary phases observed in nature are mohite and kuramite. Their occurrence is described as very rare. A numerical modelling of the stable solid phases in contact with a water solution was underwent to define stability relationships of the relevant phases of the system. The numerical modelling of the Eh-pH diagrams was carried out through the phreeqc software with the lnll.dat thermodynamic database. Owing to the complexity of this task, the subsystems Cu–O–H, Sn–O–H, Cu–S–O–H and Sn–S–O–H were firstly considered. The first Pourbaix diagram for the two naturally relevant ternary phases is then proposed.

Antibacterial Activity Of ternary semiconductor compounds AgInSe2 Nanoparticles Synthesized by Simple Chemical Method

Science.gov (United States)

Shehab, A. A.; Fadaam, S. A.; Abd, A. N.; Mustafa, M. H.

2018-05-01

In this objective AgInSe2Nanoparticles (AgInSe2 NPs) were prepared by a simple chemical method (SCM). The optica structural l and morphological properties of the synthesized AgInSe2 NPs swere investigated by using UVVI absorption atomic force microscopy AFMmf, Fourier Transform Infrared Spectroscopy and x-ray diffraction. The resistance of bacteria represents a trouble and the outlook for the use of antibiotics in the future until now uncertain. Measures must be taken to decrease this problem. Antibacterial activity of the AgInSe2 nanoparticles were exposed against several pathogenic bacteriaa including Klebsiella pneumonia KPa, Staphylococcus aureus, Bacillus subtili, Enterobacter Cloacae and Esherichia Coliby. Using a good spread method the results showed that AgInSe2 NPs had inhibitory effect versus some pathogenic bacteria with suppression area 18, 14 and 17 mm for SAgInSe2 NPs had an inhibitory effect against S Bacillus Subtilis 11 mm K EnterobactercCloacae 12 mm.

Single-step solvothermal synthesis of mesoporous Ag-TiO2-reduced graphene oxide ternary composites with enhanced photocatalytic activity

Science.gov (United States)

Arif Sher Shah, Md. Selim; Zhang, Kan; Park, A. Reum; Kim, Kwang Su; Park, Nam-Gyu; Park, Jong Hyeok; Yoo, Pil J.

2013-05-01

With growing interest in the photocatalytic performance of TiO2-graphene composite systems, the ternary phase of TiO2, graphene, and Ag is expected to exhibit improved photocatalytic characteristics because of the improved recombination rate of photogenerated charge carriers and potential contribution of the generation of localized surface plasmon resonance at Ag sites on a surface of the TiO2-graphene binary matrix. In this work, Ag-TiO2-reduced graphene oxide ternary nanocomposites were successfully synthesized by a simple solvothermal process. In a single-step synthetic procedure, the reduction of AgNO3 and graphene oxide and the hydrolysis of titanium tetraisopropoxide were spontaneously performed in a mixed solvent system of ethylene glycol, N,N-dimethylformamide and a stoichiometric amount of water without resorting to the use of typical reducing agents. The nanocomposites were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, along with different microscopic and spectroscopic techniques, enabling us to confirm the successful reduction of AgNO3 and graphite oxide to metallic Ag and reduced graphene oxide, respectively. Due to the highly facilitated electron transport of well distributed Ag nanoparticles, the synthesized ternary nanocomposite showed enhanced photocatalytic activity for degradation of rhodamine B dye under visible light irradiation.With growing interest in the photocatalytic performance of TiO2-graphene composite systems, the ternary phase of TiO2, graphene, and Ag is expected to exhibit improved photocatalytic characteristics because of the improved recombination rate of photogenerated charge carriers and potential contribution of the generation of localized surface plasmon resonance at Ag sites on a surface of the TiO2-graphene binary matrix. In this work, Ag-TiO2-reduced graphene oxide ternary nanocomposites were successfully synthesized by a simple solvothermal process. In a single-step synthetic procedure, the reduction

Facile synthesis of the flower-like ternary heterostructure of Ag/ZnO encapsulating carbon spheres with enhanced photocatalytic performance

Energy Technology Data Exchange (ETDEWEB)

Zhao, Xiaohua [School of Environment, Key Laboratory of Yellow River and Huai River Water Environment and Pollution Control (Ministry of Education), Henan Key Laboratory for Environmental Pollution Control, Henan Engineering Laboratory of Environmental Functional Materials and Pollution Control, Henan Normal University, Xinxiang, 453007 (China); School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, 453007 (China); Su, Shuai; Wu, Guangli; Li, Caizhu [School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, 453007 (China); Qin, Zhe [School of Environment, Key Laboratory of Yellow River and Huai River Water Environment and Pollution Control (Ministry of Education), Henan Key Laboratory for Environmental Pollution Control, Henan Engineering Laboratory of Environmental Functional Materials and Pollution Control, Henan Normal University, Xinxiang, 453007 (China); Lou, Xiangdong [School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, 453007 (China); Zhou, Jianguo, E-mail: zhoujgwj@163.com [School of Environment, Key Laboratory of Yellow River and Huai River Water Environment and Pollution Control (Ministry of Education), Henan Key Laboratory for Environmental Pollution Control, Henan Engineering Laboratory of Environmental Functional Materials and Pollution Control, Henan Normal University, Xinxiang, 453007 (China)

2017-06-01

Highlights: • Flower-like Ag/ZnO encapsulating carbon spheres (Ag/ZnO@C) was synthesized. • A green facile synthesis method was used. • Ag/ZnO@C exhibited better photocatalytic performance than Ag/ZnO, ZnO@C, and ZnO. • Dye and metronidazole both can be decomposed by Ag/ZnO@C. - Abstract: To utilize sunlight more effectively in photocatalytic reactions, the flower-like ternary heterostructure of Ag/ZnO encapsulating carbon spheres (Ag/ZnO@C) was successfully synthesized by a green and facile one-pot hydrothermal method. The carbon spheres (CSs) were wrapped by ZnO nanosheets, forming flower-like microstructures, and Ag nanoparticles (Ag NPs) were deposited on the surface of the ZnO nanosheets. The Ag/ZnO@C ternary heterostructure exhibited enhanced photocatalytic activity compared to those of Ag/ZnO, ZnO@C and pure ZnO for the degradation of Reactive Black GR and metronidazole under sunlight and visible light irradiation. This was attributed to the enhanced visible light absorption and effective charge separation based on the synergistic effect of ZnO, Ag NPs, and CSs. Due to the surface plasmon resonance effect of Ag NPs and surface photosensitizing effect of CSs, Ag/ZnO@C exhibited enhanced visible light absorption. Meanwhile, Ag NPs and CSs can both act as rapid electron transfer units to improve the separation of photogenerated charge carriers in Ag/ZnO@C. The primary active species were determined, and the photocatalytic mechanism was proposed. This work demonstrates an effective way to improve the photocatalytic performance of ZnO and provides information for the facile synthesis of noble metal/ZnO@C ternary heterostructure.

Ternary Weighted Function and Beurling Ternary Banach Algebra l1ω(S

Directory of Open Access Journals (Sweden)

Mehdi Dehghanian

2011-01-01

Full Text Available Let S be a ternary semigroup. In this paper, we introduce our notation and prove some elementary properties of a ternary weight function ω on S. Also, we make ternary weighted algebra l1ω(S and show that l1ω(S is a ternary Banach algebra.

Studies on highly luminescent AgInS{sub 2} and Ag–Zn–In–S quantum dots

Energy Technology Data Exchange (ETDEWEB)

Xiang, Weidong, E-mail: xiangweidong001@126.com [College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035 (China); College of Materials Science and Engineering, Tongji University, Shanghai 201804 (China); Xie, Cuiping; Wang, Jing; Zhong, Jiasong; Liang, Xiaojuan; Yang, Hailong; Luo, Le [College of Materials Science and Engineering, Tongji University, Shanghai 201804 (China); Chen, Zhaoping [College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035 (China)

2014-03-05

Highlights: • The quantum yield of the obtained ternary AgInS{sub 2} QDs was up to 62% with the emission peak of 642 nm under the excitation of 460 nm. • Colorful luminescent Ag–Zn–In–S QDs were obtained by adding Zn salts directly as well as Ag and In precursors. • The obtained highly luminescent quantum dots showed promising applications in the white light emitting diodes (W-LED). • The electroluminescence (EL) of AgInS{sub 2} QDs was observed in QD-LED device. -- Abstract: Silver indium sulfide (AIS) quantum dots (QDs) with different Ag/In molar ratios were synthesized via a hot-injection method. Intense photoluminescence (PL) originating from the donor–acceptor pair recombination were observed for all the samples and the emission peak blue-shifted from 739 to 632 nm, being similar to the behavior of the absorption onset as the Ag/In ratios decreased. The highest PL quantum yield (QY) of the obtained ternary AIS QDs was ca. 62% with an optimum ratio of Ag/In = 1/4. Compared with AIS QDs, when Zn ions were introduced, the absorption spectra of the obtained quaternary Ag–Zn–In–S QDs were blue-shifted, and their emission peaks moved to higher energies accordingly, showing a tunable emission from red to green by altering the band gap energy. In order to further study the electroluminescence (EL) as well as looking forward to the applications in the optoelectronic devices of the obtained highly luminescent nanoparticles, the colloidal AIS QDs were deposited as thin films to the sandwich-like structured QD-LED. The experimental results showed that the obtained EL device exhibited EL emission originated from QDs thin films by adjusting the turn on voltage, which is for the first time to realize EL of AIS QDs in such QD-LED.

Synthesis and characterization of the ternary telluroargentate K4[Ag18Te11

KAUST Repository

Davaasuren, Bambar; Dashjav, Enkhtsetseg; Rothenberger, Alexander

2014-01-01

The ternary potassium telluroargentate(I), K4[Ag18Te11], was prepared by solvothermal synthesis in ethylenediamine at 160 °C. It crystallizes in the cubic space group Fm3¯ m (no. 225) with the cell parameter a = 18.6589(6) Å. The crystal structure

Photoelectric properties of thin films from the CdS-Ag2 S system

International Nuclear Information System (INIS)

Ristova-Lipanovikj, Mimoza

1996-01-01

Three different methods for preparation of thin films of CdS-Ag 2 S system are presented. Those methods are modified from the already existing methods of chemical deposition, and the method of spray pyrolysis, both widely utilized for preparation of wide range of binary, ternary and quaternary semiconductor thin films. The atomic absorption method was applied for quantitative analysis of the samples. The crystal structure of the thin films was studied by X-ray diffraction, while their morphology and the texture was analyzed from the microphotographs, taken on the samples by an optical microscope, in transmitted light. An extensive research was undertaken, to improve the crystallinity of the samples, by performing a post preparation thermal treatment. Photoelectric as well as some other physical properties were studied. VIS and NIR transmission spectra were recorded. The optical band gaps for various thin films containing different portions of Ag and Cd in the system, were evaluated. Spectral dependence of the photoconductivity was recorded. The optical band gaps were determined from the positions of the corresponding maxima of the photoconductivity. From the curves of the time relaxation of the photoconductivity, the carrier life times were calculates. Measurements of the thermal dependence of the resistivity on various samples were performed. Based on the extensive experimental research, the most convenient composition for PV application was selected. For the sake of comparison, two different types of PV cells were manufactured, Sn O 2 :F/CdS:Ag-Sn x S, and Sn O 2 :F/CdS-Sn x S, in order to study the influence of the silver content in the CdS. The plots of I-V and C-V characteristics are presented, and the parameters of the solar cells, were determined and taken in a relation with the content of the silver on the CdS. Finally, some directions of a possible future experimental and theoretical research in this field are given, based on the conclusions made. (author)

Conductance switching in Ag(2)S devices fabricated by in situ sulfurization.

Science.gov (United States)

Morales-Masis, M; van der Molen, S J; Fu, W T; Hesselberth, M B; van Ruitenbeek, J M

2009-03-04

We report a simple and reproducible method to fabricate switchable Ag(2)S devices. The alpha-Ag(2)S thin films are produced by a sulfurization process after silver deposition on an Si substrate. Structure and composition of the Ag(2)S are characterized using XRD and RBS. Our samples show semiconductor behaviour at low bias voltages, whereas they exhibit reproducible bipolar resistance switching at higher bias voltages. The transition between both types of behaviour is observed by hysteresis in the I-V curves, indicating decomposition of the Ag(2)S, increasing the Ag(+) ion mobility. The as-fabricated Ag(2)S samples are a good candidate for future solid state memory devices, as they show reproducible memory resistive properties and they are fabricated by an accessible and reliable method.

Conductance switching in Ag2S devices fabricated by in situ sulfurization

International Nuclear Information System (INIS)

Morales-Masis, M; Molen, S J van der; Hesselberth, M B; Ruitenbeek, J M van; Fu, W T

2009-01-01

We report a simple and reproducible method to fabricate switchable Ag 2 S devices. The α-Ag 2 S thin films are produced by a sulfurization process after silver deposition on an Si substrate. Structure and composition of the Ag 2 S are characterized using XRD and RBS. Our samples show semiconductor behaviour at low bias voltages, whereas they exhibit reproducible bipolar resistance switching at higher bias voltages. The transition between both types of behaviour is observed by hysteresis in the I-V curves, indicating decomposition of the Ag 2 S, increasing the Ag + ion mobility. The as-fabricated Ag 2 S samples are a good candidate for future solid state memory devices, as they show reproducible memory resistive properties and they are fabricated by an accessible and reliable method.

Cooling thermal parameters and microstructure features of directionally solidified ternary Sn–Bi–(Cu,Ag) solder alloys

Energy Technology Data Exchange (ETDEWEB)

Silva, Bismarck L., E-mail: bismarck_luiz@yahoo.com.br [Department of Materials Engineering, Federal University of São Carlos, UFSCar, 13565-905 São Carlos, SP (Brazil); Garcia, Amauri [Department of Manufacturing and Materials Engineering, University of Campinas, UNICAMP, 13083-860 Campinas, SP (Brazil); Spinelli, José E. [Department of Materials Engineering, Federal University of São Carlos, UFSCar, 13565-905 São Carlos, SP (Brazil)

2016-04-15

Low temperature soldering technology encompasses Sn–Bi based alloys as reference materials for joints since such alloys may be molten at temperatures less than 180 °C. Despite the relatively high strength of these alloys, segregation problems and low ductility are recognized as potential disadvantages. Thus, for low-temperature applications, Bi–Sn eutectic or near-eutectic compositions with or without additions of alloying elements are considered interesting possibilities. In this context, additions of third elements such as Cu and Ag may be an alternative in order to reach sounder solder joints. The length scale of the phases and their proportions are known to be the most important factors affecting the final wear, mechanical and corrosions properties of ternary Sn–Bi–(Cu,Ag) alloys. In spite of this promising outlook, studies emphasizing interrelations of microstructure features and solidification thermal parameters regarding these multicomponent alloys are rare in the literature. In the present investigation Sn–Bi–(Cu,Ag) alloys were directionally solidified (DS) under transient heat flow conditions. A complete characterization is performed including experimental cooling thermal parameters, segregation (XRF), optical and scanning electron microscopies, X-ray diffraction (XRD) and length scale of the microstructural phases. Experimental growth laws relating dendritic spacings to solidification thermal parameters have been proposed with emphasis on the effects of Ag and Cu. The theoretical predictions of the Rappaz-Boettinger model are shown to be slightly above the experimental scatter of secondary dendritic arm spacings for both ternary Sn–Bi–Cu and Sn–Bi–Ag alloys examined. - Highlights: • Dendritic growth prevailed for the ternary Sn–Bi–Cu and Sn–Bi–Ag solder alloys. • Bi precipitates within Sn-rich dendrites were shown to be unevenly distributed. • Morphology and preferential region for the Ag{sub 3}Sn growth depend on Ag

Ag nanoprisms with Ag₂S attachment.

KAUST Repository

Xiong, Shenglin; Xi, Baojuan; Zhang, Kang; Chen, Yifei; Jiang, Jianwen; Hu, Jiangyong; Zeng, Hua Chun

2013-01-01

Triangular Ag nanoprisms are a type of most-studied noble-metal nanostructures over the past decade owing to their special structural architecture and outstanding optical and catalytic properties for a wide range of applications. Nevertheless, in contrast to active research for the synthesis of phase-pure Ag nanoprisms, no asymmetric heterodimers containing Ag prisms have been developed so far, probably due to lack of suitable synthetic methods. Herein, we devise a simple ion-exchange method to synthesize Ag2S/Ag heterodimers at room temperature, through which Ag nanoprisms with controllable size and thickness can be fabricated. Formation chemistry and optical properties of the heterodimers have been investigated. These semiconductor/metal heterodimers have exhibited remarkable bactericidal activity to E. coli cells under visible light illumination.

Synthesis and properties of Ag/ZnO/g-C3N4 ternary micro/nano composites by microwave-assisted method

Science.gov (United States)

Zhang, Zijie; Li, Xuexue; Chen, Haitao; Shao, Gang; Zhang, Rui; Lu, Hongxia

2018-01-01

Ag/ZnO/g-C3N4 ternary micro/nanocomposites, as novel visible-light-driven photocatalysts, were prepared by a simple and convenient microwave-assisted method. The resulting ternary structure micro/nano composites were characterized by x-ray diffraction, x-ray photoelectron spectroscopy, scanning electron microscopy, ultraviolet-visible diffuse reflectance spectroscopy and infrared radiation techniques to examine its phase structure, valence state, morphological, thermal and optical properties. Well crystallized Ag/ZnO/g-C3N4 ternary micro/nano composites were synthesized under microwave-radiation for 15 min with the output of 240 W. Further experiments indicated Ag(5.0mol%)/ZnO/g-C3N4 photocatalyst in degradation of methylene blue exhibited an outstanding photocatalytic activity and its reaction rate constant (k, 0.0084 min-1) is 7.5, 2.4 2.9 and 3.5 times higher than that of monolithic ZnO (k, 0.0011 min-1), ZnO/g-C3N4(k, 0.0035 min-1), Ag(5 mol%)/ZnO(k, 0.0029 min-1) and Ag(5mol%)/g-C3N4 (k, 0.0024 min-1) respectively. Finally, a possible photocatalytic mechanism of Ag/ZnO/g-C3N4 photocatalyst in degradation process was proposed. This work provides a feasible strategy to synthesize an efficient ZnO-based photocatalyst which combines structure and properties of different dimensional components and made this ternary system an exciting candidate for sunlight-driven photocatalytic water treatment.

Ag-CuO-ZnO metal-semiconductor multiconcentric nanotubes for achieving superior and perdurable photodegradation.

Science.gov (United States)

Xu, Kaichen; Wu, Jiagen; Tan, Chuan Fu; Ho, Ghim Wei; Wei, Ang; Hong, Minghui

2017-08-17

Solar energy represents a robust and natural form of resource for environment remediation via photocatalytic pollutant degradation with minimum associated costs. However, due to the complexity of the photodegradation process, it has been a long-standing challenge to develop reliable photocatalytic systems with low recombination rates, excellent recyclability, and high utilization rates of solar energy, especially in the visible light range. In this work, a ternary hetero-nanostructured Ag-CuO-ZnO nanotube (NT) composite is fabricated via facile and low-temperature chemical and photochemical deposition methods. Under visible light irradiation, the as-synthesized ZnO NT based ternary composite exhibits a greater enhancement (∼300%) of photocatalytic activity than its counterpart, Ag-CuO-ZnO nanorods (NRs), in pollutant degradation. The enhanced photocatalytic capability is primarily attributed to the intensified visible light harvesting, efficient charge carrier separation and much larger surface area. Furthermore, our as-synthesised hybrid ternary Ag-CuO-ZnO NT composite demonstrates much higher photostability and retains ∼98% of degradation efficiency even after 20 usage cycles, which can be mainly ascribed to the more stable polar planes of ZnO NTs than those of ZnO NRs. These results afford a new route to construct ternary heterostructured composites with perdurable performance in sewage treatment and photocorrosion suppression.

Ternary ZnO/AgI/Ag{sub 2}CO{sub 3} nanocomposites: Novel visible-light-driven photocatalysts with excellent activity in degradation of different water pollutants

Energy Technology Data Exchange (ETDEWEB)

Golzad-Nonakaran, Behrouz; Habibi-Yangjeh, Aziz, E-mail: ahabibi@uma.ac.ir

2016-12-01

ZnO/AgI/Ag{sub 2}CO{sub 3} nanocomposites with different Ag{sub 2}CO{sub 3} contents were fabricated by a facile ultrasonic-irradiation method. The resultant samples were fairly characterized using XRD, EDX, SEM, TEM, UV–vis DRS, FT-IR, and PL techniques to reveal their microstructure, purity, morphology, and spectroscopic properties. Photocatalytic activity of the prepared samples was investigated by photodegradation of four dye pollutants (rhodamine B, methyl orange, methylene blue, and fuchsine) under visible-light irradiation. The photocatalytic experiments in degradation of rhodamine B showed that the ternary ZnO/AgI/Ag{sub 2}CO{sub 3} (30%) nanocomposite has an enhanced activity nearly 19 and 14 times higher than those of the binary ZnO/Ag{sub 2}CO{sub 3} and ZnO/AgI photocatalysts, respectively. Based on the obtained results, the highly enhanced activity was attributed to generation of more electron-hole pairs under visible-light irradiation and separation of the photogenerated charge carriers due to formation of tandem n-n heterojunctions between counterparts of the nanocomposite. The active species trapping experiments were also examined and it was showed that superoxide ion radicals play a vital role in the photocatalytic degradation reaction. More importantly, the ternary photocatalyst demonstrated good photostability. - Highlights: • ZnO/AgI/Ag{sub 2}CO{sub 3} nanocomposites were fabricated by an ultrasonic-irradiation method. • The activity was investigated by photodegradation of four dyes under visible light. • ZnO/AgI/Ag{sub 2}CO{sub 3} (30%) nanocomposite has the best activity under visible light. • Activity is 19 and 14-folds higher than ZnO/Ag{sub 2}CO{sub 3} and ZnO/AgI in degradation of RhB.

Probability of ternary fission of 93Nb andnat Ag nuclei induced by 0.8-1.8 GeV photons

International Nuclear Information System (INIS)

Lima, D.A. de; Milomen, W.C.C.; Tavares, O.A.P.

1989-01-01

The yields of ternary fission of 93 Nb and nat Ag nuclei induced by bremsstrahlung photons of 0.8, 1.0, 1.4 and 1.8 GeV end-point energies have been measured by using the 2 Π-forward geometry with thick target metal foils in contact with makrofol polycarbonate sheets as fission-track detectors. Absolute mean cross sections per photon in the range 0.8-1.8 GeV have been obtained as 0.3 ± 0.3 μb and 0.5 ± μb, respectively, for 93 Nb and nat Ag nuclei. These correspond to a probability of ternary fission of approx. 10 -5 for both nuclei. Results are discussed and compared with previous ternary fission data obtained for nuclei of A [pt

The role of In in III-nitride ternary semiconductors

CERN Multimedia

Redondo cubero, A

This proposal aims to study the role of In in the outstanding efficiency of luminescent devices based on group III-nitride ternary semiconductors. To study the microscopic environments of In in GaInN and AlInN, Perturbed Angular Correlation (PAC) experiments will be performed using the PAC-probes $^{111m}$Cd($^{111}$Cd), $^{115}$Cd($^{115}$In) and $^{117}$Cd($^{117}$In). Temperature dependent PAC measurements using the $^{111}$In($^{111}$Cd) probe indicated that In in GaN and AlN forms a complex with a defect, possibly a nitrogen vacancy (V$_{N}$), which is stable up to high temperatures and might be involved in the luminescence mechanisms. Analysing these results two questions arose: \\\\ \\\\1. Does the fact that the actual measurement is performed with the daughter nucleus $^{111}$Cd (being an acceptor) influence the probe-defect interaction? This question can be answered by performing measurements with the complementary probe $^{117}$Cd($^{117}$In). \\\\ \\\\ 2. What is the significance of $\\textit{a...

Direct femtosecond observation of charge carrier recombination in ternary semiconductor nanocrystals: The effect of composition and shelling

KAUST Repository

Bose, Riya

2015-02-12

Heavy-metal free ternary semiconductor nanocrystals are emerging as key materials in photoactive applications. However, the relative abundance of intra-bandgap defect states and lack of understanding of their origins within this class of nanocrystals are major factors limiting their applicability. To remove these undesirable defect states which considerably shorten the lifetimes of photogenerated excited carriers, a detailed understanding about their origin and nature is required. In this report, we monitor the ultrafast charge carrier dynamics of CuInS2 (CIS), CuInSSe (CISSe), and CuInSe2 (CISe) nanocrystals, before and after ZnS shelling, using state-of-the-art time-resolved laser spectroscopy with broadband capabilities. The experimental results demonstrate the presence of both electron and hole trapping intra-bandgap states in the nanocrystals which can be removed significantly by ZnS shelling, and the carrier dynamics is slowed down. Another important observation remains the reduction of carrier lifetime in the presence of Se, and the shelling strategy is observed to be less effective at suppressing trap states. This study provides quantitative physical insights into the role of anion composition and shelling on the charge carrier dynamics in ternary CIS, CISSe, and CISe nanocrystals which are essential to improve their applicability for photovoltaics and optoelectronics.

Phase transitions during formation of Ag nanoparticles on In{sub 2}S{sub 3} precursor layers

Energy Technology Data Exchange (ETDEWEB)

Liu, Yang, E-mail: yang.liu@helmholtz-berlin.de; Fu, Yanpeng; Dittrich, Thomas; Sáez-Araoz, Rodrigo; Schmid, Martina; Hinrichs, Volker; Lux-Steiner, Martha Ch.; Fischer, Christian-Herbert

2015-09-01

Phase transitions have been investigated for silver deposition onto In{sub 2}S{sub 3} precursor layers by spray chemical vapor deposition from a trimethylphosphine (hexafluoroacetylacetonato) silver (Ag(hfacac)(PMe{sub 3})) solution. The formation of Ag nanoparticles (Ag NPs) on top of the semiconductor layer set on concomitant with the formation of AgIn{sub 5}S{sub 8}. The increase of the diameter of Ag NPs was accompanied by the evolution of orthorhombic AgInS{sub 2}. The formation of Ag{sub 2}S at the interface between Ag NPs and the semiconductor layer was observed. Surface photovoltage spectroscopy indicated charge separation and electronic transitions in the ranges of corresponding band gaps. The phase transition approach is aimed to be applied for the formation of plasmonic nanostructures on top of extremely thin semiconducting layers. - Highlights: • Silver nanoparticles were deposited onto In{sub 2}S{sub 3} precursor layer by spray pyrolysis. • The silver nanoparticle size and density could be controlled by deposition time. • Phase transitions during deposition and material properties were investigated. • The layers still show semiconducting properties after phase transitions. • Plasmonic absorption enhancement has been demonstrated.

Strain/size analysis in ternary compounds AgIn{sub 5} VI{sub 8} (Vi = S, Se, Te) by X-ray diffraction; Analisis de tension/tamano en compuestos ternarios AgIn{sub 5} VI{sub 8} (VI = S, Se, Te) mediante difraccion de rayos X

Energy Technology Data Exchange (ETDEWEB)

Fermin, J. R.; Salcedo, D. Y.; Durante R, C.; Castro, J. A. [Universidad del Zulia, Facultad Experimental de Ciencias, Departamento de Fisica, Maracaibo, Zulia (Venezuela, Bolivarian Republic of)

2017-11-01

In this work, we have study the microstructural properties of the ternary compounds AgIn{sub 5} VI{sub 8} (Vi = S, Se, Te) by X-ray diffraction technique (XRD). The linewidth of the XRD profile is measured as function of the diffraction angle. Structural parameters such as, average grain size, micro strains, and crystalline dislocation density, are obtained on the framework of a strain/size analysis based on the modified Scherrer equation for Gaussian profiles. The crystalline dislocation arrange according to a Gaussian distribution function, indicating that these dislocations are randomly distributed within the grains. (Author)

Conductance switching in Ag{sub 2}S devices fabricated by in situ sulfurization

Energy Technology Data Exchange (ETDEWEB)

Morales-Masis, M; Molen, S J van der; Hesselberth, M B; Ruitenbeek, J M van [Kamerlingh Onnes Laboratorium, Universiteit Leiden, PO Box 9504, 2300 RA Leiden (Netherlands); Fu, W T [Leiden Institute of Chemistry, Gorlaeus Laboratorium, Universiteit Leiden, PO Box 9502, 2300 RA Leiden (Netherlands)], E-mail: ruitenbeek@physics.leidenuniv.nl

2009-03-04

We report a simple and reproducible method to fabricate switchable Ag{sub 2}S devices. The {alpha}-Ag{sub 2}S thin films are produced by a sulfurization process after silver deposition on an Si substrate. Structure and composition of the Ag{sub 2}S are characterized using XRD and RBS. Our samples show semiconductor behaviour at low bias voltages, whereas they exhibit reproducible bipolar resistance switching at higher bias voltages. The transition between both types of behaviour is observed by hysteresis in the I-V curves, indicating decomposition of the Ag{sub 2}S, increasing the Ag{sup +} ion mobility. The as-fabricated Ag{sub 2}S samples are a good candidate for future solid state memory devices, as they show reproducible memory resistive properties and they are fabricated by an accessible and reliable method.

Effective Electron Transfer Pathway of the Ternary TiO2/RGO/Ag Nanocomposite with Enhanced Photocatalytic Activity under Visible Light

Directory of Open Access Journals (Sweden)

Hongwei Tian

2017-05-01

Full Text Available Mesoporous TiO2/reduced graphene oxide/Ag (TiO2/RGO/Ag ternary nanocomposite with an effective electron transfer pathway is obtained by an electrostatic self-assembly method and photo-assisted treatment. Compared with bare mesoporous TiO2 (MT and mesoporous TiO2/RGO (MTG, the ternary mesoporous TiO2/RGO/Ag (MTGA nanocomposite exhibited superior photocatalytic performance for the degradation of methylene blue (MB under visible light, and the degradation rate reached 0.017 min−1, which was 3.4-times higher than that of MTG. What is more, the degradation rate of MTGA nanocomposite after three cycle times is 91.2%, and the composition is unchanged. In addition, we found that the OH•, h+ and especially O2•− contribute to the high photocatalytic activity of MTGA for MB degradation. It is proposed that Ag nanoparticles can form the local surface plasmon resonance (LSPR to absorb the visible light and distract the electrons into MT, and RGO can accept the electrons from MT to accelerate the separation efficiency of photogenerated carriers. The establishment of MTGA ternary nanocomposite makes the three components act synergistically to enhance the photocatalytic performance.

Investigation of the growth and in situ heating transmission electron microscopy analysis of Ag2S-catalyzed ZnS nanowires

Science.gov (United States)

Kim, Jung Han; Kim, Jong Gu; Song, Junghyun; Bae, Tae-Sung; Kim, Kyou-Hyun; Lee, Young-Seak; Pang, Yoonsoo; Oh, Kyu Hwan; Chung, Hee-Suk

2018-04-01

We investigated the semiconductor-catalyzed formation of semiconductor nanowires (NWs) - silver sulfide (Ag2S)-catalyzed zinc sulfide (ZnS) NWs - based on a vapor-liquid-solid (VLS) growth mechanism through metal-organic chemical vapor deposition (MOCVD) with a Ag thin film. The Ag2S-catalyzed ZnS NWs were confirmed to have a wurtzite structure with a width and length in the range of ∼30 nm to ∼80 nm and ∼1 μm, respectively. Using extensive transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS) analyses from plane and cross-sectional viewpoints, the ZnS NWs were determined to have a c-axis, [0001] growth direction. In addition, the catalyst at the top of the ZnS NWs was determined to consist of a Ag2S phase. To support the Ag2S-catalyzed growth of the ZnS NWs by a VLS reaction, an in situ heating TEM experiment was conducted from room temperature to 840 °C. During the experiment, the melting of the Ag2S catalyst in the direction of the ZnS NWs was first observed at approximately 480 °C along with the formation of a carbon (C) shell. Subsequently, the Ag2S catalyst melted completely into the ZnS NWs at approximately 825 °C. As the temperature further increased, the Ag2S and ZnS NWs continuously melted and vaporized up to 840 °C, leaving only the C shell behind. Finally, a possible growth mechanism was proposed based on the structural and chemical investigations.

Experimental investigation of the Ag–Bi–I ternary system and thermodynamic properties of the ternary phases

International Nuclear Information System (INIS)

Mashadieva, Leyla F.; Aliev, Ziya S.; Shevelkov, Andrei V.; Babanly, Mahammad B.

2013-01-01

Highlights: ► The self-consistent phase diagram of the Ag–Bi–I system is constructed. ► Ag 2 BiI 5 and AgBi 2 I 7 are the only ternary phases of the system. ► Standard thermodynamic functions of formation and the standard entropies of Ag 2 BiI 5 and AgBi 2 I 7 are calculated. - Abstract: The phase equilibriums in the Ag–Bi–I ternary system and thermodynamic properties of the ternary phases were experimentally determined by using DTA and XRD techniques and EMF measurements with the Ag 4 RbI 5 solid electrolyte. According to the obtained experimental results, the polythermal sections of the ternary phase diagram, its isothermal section at 300 K as well as the projection of the liquids surface have been revised. The fields of the primary crystallization and types and coordinates of nonvariant and monovariant equilibriums were determined. The partial molar functions of silver iodide and silver in the alloys as well as the standard thermodynamic functions of formation and the standard entropies of Ag 2 BiI 5 and AgBi 2 I 7 were calculated based on EMF measurements.

Electronic structure of Ag8GeS6

Directory of Open Access Journals (Sweden)

D.I. Bletskan

2017-04-01

Full Text Available For the first time, the energy band structure, total and partial densities of states of Ag8GeS6 crystal were calculated using the ab initio density functional method in LDA and LDA+U approximations. Argyrodite is direct-gap semiconductor with the calculated band gap width Egd = 1.46 eV in the LDA+U approximation. The valence band of argyrodite contains four energy separated groups of occupied subzones. The unique feature of electron-energy structure of Ag8GeS6 crystal is the energy overlapping between the occupied d-states of Ag atoms and the delocalized valence p-states of S atoms in relatively close proximity to the valence band top.

The effect of dielectric constants on noble metal/semiconductor SERS enhancement: FDTD simulation and experiment validation of Ag/Ge and Ag/Si substrates.

Science.gov (United States)

Wang, Tao; Zhang, Zhaoshun; Liao, Fan; Cai, Qian; Li, Yanqing; Lee, Shuit-Tong; Shao, Mingwang

2014-02-11

The finite-difference time-domain (FDTD) method was employed to simulate the electric field distribution for noble metal (Au or Ag)/semiconductor (Ge or Si) substrates. The simulation showed that noble metal/Ge had stronger SERS enhancement than noble metal/Si, which was mainly attributed to the different dielectric constants of semiconductors. In order to verify the simulation, Ag nanoparticles with the diameter of ca. 40 nm were grown on Ge or Si wafer (Ag/Ge or Ag/Si) and employed as surface-enhanced Raman scattering substrates to detect analytes in solution. The experiment demonstrated that both the two substrates exhibited excellent performance in the low concentration detection of Rhodamine 6G. Besides, the enhancement factor (1.3 × 10(9)) and relative standard deviation values (less than 11%) of Ag/Ge substrate were both better than those of Ag/Si (2.9 × 10(7) and less than 15%, respectively), which was consistent with the FDTD simulation. Moreover, Ag nanoparticles were grown in-situ on Ge substrate, which kept the nanoparticles from aggregation in the detection. To data, Ag/Ge substrates showed the best performance for their sensitivity and uniformity among the noble metal/semiconductor ones.

Development of aluminum (Al5083)-clad ternary Ag-In-Cd alloy for JSNS decoupled moderator

International Nuclear Information System (INIS)

Teshigawara, M.; Harada, M.; Saito, S.; Oikawa, K.; Maekawa, F.; Futakawa, M.; Kikuchi, K.; Kato, T.; Ikeda, Y.; Naoe, T.; Koyama, T.; Ooi, T.; Zherebtsov, S.; Kawai, M.; Kurishita, H.; Konashi, K.

2006-01-01

To develop Ag (silver)-In (indium)-Cd (cadmium) alloy decoupler, a method is needed to bond the decoupler between Al alloy (Al5083) and the ternary Ag-In-Cd alloy. We found that a better HIP condition was temperature, pressure and holding time at 803 K, 100 MPa and 10 min. for small test pieces (φ22 mm in dia. x 6 mm in height). Hardened layer due to the formation of AlAg 2 was found in the bonding layer, however, the rupture strength of the bonding layer is more than 30 MPa, the calculated design stress. Bonding tests of a large size piece (200 x 200 x 30 mm 3 ), which simulated the real scale, were also performed according to the results of small size tests. The result also gave good bonding and enough required-mechanical-strength

Design of medium band gap Ag-Bi-Nb-O and Ag-Bi-Ta-O semiconductors for driving direct water splitting with visible light.

Science.gov (United States)

Wang, Limin; Cao, Bingfei; Kang, Wei; Hybertsen, Mark; Maeda, Kazuhiko; Domen, Kazunari; Khalifah, Peter G

2013-08-19

Two new metal oxide semiconductors belonging to the Ag-Bi-M-O (M = Nb, Ta) chemical systems have been synthesized as candidate compounds for driving overall water splitting with visible light on the basis of cosubstitution of Ag and Bi on the A-site position of known Ca2M2O7 pyrochlores. The low-valence band edge energies of typical oxide semiconductors prevents direct water splitting in compounds with band gaps below 3.0 eV, a limitation which these compounds are designed to overcome through the incorporation of low-lying Ag 4d(10) and Bi 6s(2) states into compounds of nominal composition "AgBiM2O7". It was found that the "AgBiTa2O7" pyrochlores are in fact a solid solution with an approximate range of Ag(x)Bi(5/6)Ta2O(6.25+x/2) with 0.5 semiconductors with the onset of strong direct absorption at 2.72 and 2.96 eV, respectively. Electronic structure calculations for an ordered AgBiNb2O7 structure show that the band gap reduction and the elevation of the valence band primarily result from hybridized Ag d(10)-O 2p orbitals that lie at higher energy than the normal O 2p states in typical pyrochlore oxides. While the minimum energy gap is direct in the band structure, the lowest energy dipole allowed optical transitions start about 0.2 eV higher in energy than the minimum energy transition and involve different bands. This suggests that the minimum electronic band gap in these materials is slightly smaller than the onset energy for strong absorption in the optical measurements. The elevated valence band energies of the niobate and tantalate compounds are experimentally confirmed by the ability of these compounds to reduce 2 H(+) to H2 gas when illuminated after functionalization with a Pt cocatalyst.

Ag2S/CdS/TiO2 Nanotube Array Films with High Photocurrent Density by Spotting Sample Method.

Science.gov (United States)

Sun, Hong; Zhao, Peini; Zhang, Fanjun; Liu, Yuliang; Hao, Jingcheng

2015-12-01

Ag2S/CdS/TiO2 hybrid nanotube array films (Ag2S/CdS/TNTs) were prepared by selectively depositing a narrow-gap semiconductor-Ag2S (0.9 eV) quantum dots (QDs)-in the local domain of the CdS/TiO2 nanotube array films by spotting sample method (SSM). The improvement of sunlight absorption ability and photocurrent density of titanium dioxide (TiO2) nanotube array films (TNTs) which were obtained by anodic oxidation method was realized because of modifying semiconductor QDs. The CdS/TNTs, Ag2S/TNTs, and Ag2S/CdS/TNTs fabricated by uniformly depositing the QDs into the TNTs via the successive ionic layer adsorption and reaction (SILAR) method were synthesized, respectively. The X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectrum (XPS) results demonstrated that the Ag2S/CdS/TNTs prepared by SSM and other films were successfully prepared. In comparison with the four films of TNTs, CdS/TNTs, Ag2S/TNTs, and Ag2S/CdS/TNTs by SILAR, the Ag2S/CdS/TNTs prepared by SSM showed much better absorption capability and the highest photocurrent density in UV-vis range (320~800 nm). The cycles of local deposition have great influence on their photoelectric properties. The photocurrent density of Ag2S/CdS/TNTs by SSM with optimum deposition cycles of 6 was about 37 times that of TNTs without modification, demonstrating their great prospective applications in solar energy utilization fields.

Temperature and frequency response of conductivity in Ag2S doped chalcogenide glassy semiconductor

Science.gov (United States)

Ojha, Swarupa; Das, Anindya Sundar; Roy, Madhab; Bhattacharya, Sanjib

2018-06-01

The electric conductivity of chalcogenide glassy semiconductor xAg2S-(1-x)(0.5S-0.5Te) has been presented here as a function of temperature and frequency. Formation of different nanocrystallites has been confirmed from X-ray diffraction study. It is also noteworthy that average size of nanocrystallites decreases with the increase of dislocation density. Dc conductivity data have been interpreted using Mott's model and Greaves's model in low and high temperature regions respectively. Ac conductivity above the room temperature has been analyzed using Meyer-Neldel (MN) conduction rule. It is interestingly noted that Correlated Barrier Hopping (CBH) model is the most appropriate conduction mechanism for x = 0.35, where pairs of charge carrier are considered to hop over the potential barrier between the sites via thermal activation. To interpret experimental data for x = 0.45, modified non-overlapping small polaron tunnelling (NSPT) model is supposed to be appropriate model due to tunnelling through grain boundary. The conductivity spectra at various temperatures have been analyzed using Almond-West Formalism (power law model). Scaling of conductivity spectra reveals that electrical relaxation process of charge carriers (polaron) is temperature independent but depends upon the composition of the present chalcogenide glassy system.

Substrate effects on the formation of flat Ag films on (110) surfaces of III-V compound semiconductors

International Nuclear Information System (INIS)

Chao, K.; Zhang, Z.; Ebert, P.; Shih, C.K.

1999-01-01

Ag films grown at 135 K on (110) surfaces of III-V compound semiconductors and annealed at room temperature are investigated by scanning tunneling microscopy and low-energy electron diffraction. Ag films on Ga-V semiconductors are well ordered, atomically flat, and exhibit a specific critical thickness, which is a function of the substrate material. Films grown on In-V semiconductors are still rather flat, but significantly more disordered. The (111) oriented Ag films on III-arsenides and III-phosphides exhibit a clear twofold superstructure. Films on III-antimonides exhibit threefold low-energy electron diffraction images. The morphology of the Ag films can be explained on the basis of the electronic growth mechanism. copyright 1999 The American Physical Society

Ag2S/CdS/TiO2 Nanotube Array Films with High Photocurrent Density by Spotting Sample Method

OpenAIRE

Sun, Hong; Zhao, Peini; Zhang, Fanjun; Liu, Yuliang; Hao, Jingcheng

2015-01-01

Ag2S/CdS/TiO2 hybrid nanotube array films (Ag2S/CdS/TNTs) were prepared by selectively depositing a narrow-gap semiconductor—Ag2S (0.9 eV) quantum dots (QDs)—in the local domain of the CdS/TiO2 nanotube array films by spotting sample method (SSM). The improvement of sunlight absorption ability and photocurrent density of titanium dioxide (TiO2) nanotube array films (TNTs) which were obtained by anodic oxidation method was realized because of modifying semiconductor QDs. The CdS/TNTs, Ag2S/TNT...

Synthesis, characterization, and photo-physical properties of nano-crystallites of CdyZn1-yS semiconductors

International Nuclear Information System (INIS)

Cizeron, Joel

1996-01-01

This research thesis reports the study of the synthesis of particles of semiconductor with a hybrid composition (Cd y Zn 1-y S) in an inverse micellar system. This system is made of nano-scopic water droplets suspended in oil by Brownian movement. Inverse micelles of AOT/water/alkane have been successfully used in laboratory to synthesize semiconductor particles (CdS, Ag 2 S, AgI, PbS) and metallic particles (Ag, Cu, Co) with a diameter of few nanometers. The objective has been to demonstrate the feasibility of synthesises of solid solution with a composition controlled by colloidal techniques. It was then possible to identify new information on the mechanism which governs the size of semiconductor particles. Optical properties of these particles were then studied. These nano-particles exhibit a displacement of their exciton towards high energies; it is the so-called size quantum effect. This effect has been analysed for the particles and their fluorescence [fr

Deformation effects in electronic spectra of the layered semiconductors TlGaS sub 2 , TlGaSe sub 2 and TlInS sub 2

CERN Document Server

Allakhverdiev, K R; Suleymanov, R A; Gasanov, N Z

2003-01-01

The deformation effects in electronic spectra of the ternary layered semiconductors TlGaS sub 2 , TlGaSe sub 2 and TlInS sub 2 are considered. It is shown that the influence of hydrostatic pressure, thermal expansion and variation of composition in solid solutions on the band gap of the crystals investigated can be described in the framework of one common model of deformation potentials. This model appears to be close to that of layered semiconductors of the A sub 3 B sub 6 group, attesting to the fact that the main principles of formation of band structure in these two groups of layered crystals are the same.

Sunlight impelled photocatalytic pursuance of Ag-TiO2-SGO and Pt-TiO2-SGO ternary nanocomposites on rhodamine B degradation

Science.gov (United States)

Alamelu, K.; Ali, B. M. Jaffar

2018-04-01

We demonstrate a hydrothermal method combined with polyol reduction process for the synthesis of an Ag-TiO2-SGO and Pt-TiO2-SGO ternary nanocomposites in which the Ag, Pt and TiO2 nanoparticles are dispersed on the Sulfonated graphene oxide nanosheets. The structural and optical properties of obtained nanocomposites were characterized by XRD, UV-DRS, Raman, FTIR and Photoluminescence spectroscopy. The nanocomposites shows increased light absorption ability in the visible region due to surface plasmon resonance effect of noble metal. The rate of electron-hole pair recombination was significating reduced for nanocomposites system compare to pure. Also, their Performance for the photocatalytic degradation of Rhodamine B as a model organic pollutant is explored. The results showed that Ag-TiO2-SGO and Pt-TiO2-SGO nanocomposites could degrade 95% of the dye within 90 min, under natural sunlight irradiation. The reaction kinetics of ternary nanocomposites exhibit more than 2.2 fold increased photocatalytic activity compared to pristine TiO2. Sulfonated graphene based ternary photocatalyst are potential candidates for wastewater treatment in real time application, due to this ability degrade cationic and anionic dyes.

The irradiation influence on the properties of silver sulfide (Ag2S) colloidal nanoparticles

Science.gov (United States)

Rempel, S. V.; Kuznetsova, Yu. V.; Gerasimov, E. Yu.; Rempel', A. A.

2017-08-01

The aqueous solutions of different stability containing silver sulfide (Ag2S) nanoparticles are studied. The stable, transparent, and turbid solutions have been subjected to daylight for 7 months, to ultraviolet and laser irradiation, as well as to an electron beam. Solar radiation is found to favor the Ag2S reduction to Ag and/or the formation of Ag2S/Ag hybrid nanoparticles in the solution. At a high amount of hybrid nanoparticles, the exciton-plasmon interaction causes asymmetry in the absorption spectra. The exposure of Ag2S particles precipitated from the solution with the electron beam leads to the reversible growth of Ag threads. The possible exciton-plasmon interplay mechanisms in Ag2S/Ag hybrid nanoparticles are considered. The physical mechanisms of the changing Ag2S stoichiometry, the formation of metallic Ag and Ag2S/Ag hybrid nanoparticles are the generation of hot carriers and the energy transfer (exciton-plasmon interaction) in a metal-semiconductor hybrid nanosystem are elucidated, as well.

Thermodynamic properties of solid solutions in the system Ag2S–Ag2Se

International Nuclear Information System (INIS)

Pal’yanova, G.A.; Chudnenko, K.V.; Zhuravkova, T.V.

2014-01-01

We have summarized experimental data on the phase diagram of the system Ag 2 S–Ag 2 Se. Standard thermodynamic functions of four solid solutions in this system have been calculated using the model of regular and subregular solutions: a restricted fcc solid solution γ-Ag 2 S-Ag 2 S 1−x Se x (x 2 S–Ag 2 Se, monoclinic solid solution (α) from Ag 2 S to Ag 2 S 0.4 Se 0.6 , and orthorhombic solid solution (α) from Ag 2 S 0.3 Se 0.7 to the Ag 2 Se. G mix and S mix have been evaluated using the subregular model for asymmetric solution for the region Ag 2 S 0.4 Se 0.6 –Ag 2 S 0.3 Se 0.7 . The thermodynamic data can be used for modeling in complex natural systems and in matters of semiconductor materials

Structural Investigation of Photocatalyst Solid Ag1−xCuxInS2 Quaternary Alloys Sprayed Thin Films Optimized within the Lattice Compatibility Theory (LCT Scope

Directory of Open Access Journals (Sweden)

A. Colantoni

2014-01-01

Full Text Available CuxAg1−xInS2 solid thin films were fabricated through a low-cost process. Particular process-related enhanced properties lead to reaching a minimum of lattice mismatch between absorber and buffer layers within particular solar cell devices. First, copper-less samples X-ray diffraction analysis depicts the presence of AgInS2 ternary compound in chalcopyrite tetragonal phase with privileged (112 peak (d112=1.70 Å according to JCPDS 75-0118 card. Second, when x content increases, we note a shift of the same preferential orientation (112 and its value reaches 1.63 Å corresponding to CuInS2 chalcopyrite tetragonal material according to JCPDS 89-6095 file. Finally, the formation and stability of these quaternaries have been discussed in terms of the lattice compatibility in relation with silver-copper duality within indium disulfide lattice structure. Plausible explanations for the extent and dynamics of copper incorporation inside AgInS2 elaborated ternary matrices have been proposed.

Experimental study of the Ag-Sn-In phase diagram

International Nuclear Information System (INIS)

Vassilev, Gueorgui P.; Dobrev, Evgueni S.; Tedenac, Jean-Claude

2005-01-01

Combined metallographic, differential scanning calorimetry, X-ray and scanning electron microscopy studies have been performed using 27 ternary alloys. The microhardness of the α(Ag), ε(Ag 3 Sn) and ζ(Ag 4 Sn,Ag 3 In) phases has been measured. The ternary extension of the phase φ(Ag x In y Sn z , where x ∼ 0.36, y ∼ 0.61, z ∼ 0.03) has been revealed in some specimens, although the binary compound (AgIn 2 ) melts at 166 deg. C. This finding is attributed to the limited cooling rate. The solubility ranges of the solid solution and the intermetallic phases have been determined. The tin and the indium show approximately equal mutual solubility (around 2 at.%) in the ternary extensions of their Ag-Sn or Ag-In phases. The experimental data have been compared with a calculated isothermal section at 280 deg. C and with a vertical section at 2.5 at.% Ag. The thermal analyses have confirmed, in general, the temperatures of the invariant reactions in the Ag-Sn-In system as calculated by literature data

Liquidus Projection and Thermodynamic Modeling of a Sn-Ag-Zn System

Science.gov (United States)

Chen, Sinn-wen; Chiu, Wan-ting; Gierlotka, Wojciech; Chang, Jui-shen; Wang, Chao-hong

2017-12-01

Sn-Ag-Zn alloys are promising Pb-free solders. In this study, the Sn-Ag-Zn liquidus projection was determined, and the Sn-Ag-Zn thermodynamic modeling was developed. Various Sn-Ag-Zn alloys were prepared. Their as-cast microstructures and primary solidification phases were examined. The invariant reaction temperatures of the ternary Sn-Ag-Zn system were determined. The liquidus projection of the Sn-Ag-Zn ternary system was constructed. It was found that the Sn-Ag-Zn ternary system has eight primary solidification phases: ɛ2-AgZn3, γ-Ag5Zn8, β-AgZn, ζ-Ag4Sn, (Ag), ɛ1-Ag3Sn, β-(Sn) and (Zn) phases. There are eight ternary invariant reactions, and the liquid + (Ag) = β-AgZn + ζ-Ag4Sn reaction is of the highest temperature at 935.5 K. Thermodynamic modeling of the ternary Sn-Ag-Zn system was also carried out in this study based on the thermodynamic models of the three constituent binary systems and the experimentally determined liquidus projection. The liquidus projection and the isothermal sections are calculated. The calculated and experimentally determined liquidus projections are in good agreement.

Photoelectric properties of ZnO/Ag2S heterostructure and its photoelectric ethanol sensing characteristics

International Nuclear Information System (INIS)

Zhang Yu; Liu Bingkun; Wang Dejun; Lin Yanhong; Xie Tengfeng; Zhai Jiali

2012-01-01

Highlights: ► The ZnO/Ag 2 S heterostructure shows good photoelectric properties under visible-light irradiation. ► Transient photovoltage results reveal the separation process of photo-generated charges and give further evidence of interfacial effects. ► Photoelectric ethanol sensing characteristics have been found for the ZnO/Ag 2 S heterostructure at room temperature. - Abstract: The photoelectric properties of ZnO microspheres, ZnO/Ag 2 S heterogeneous microspheres and Ag 2 S hollow microspheres were investigated systematically by surface photovoltage, transient photovoltage and surface photocurrent techniques. The ZnO/Ag 2 S heterostructure shows superior photoelectric properties in visible-light region compared with pure Ag 2 S. Transient photovoltage results reveal the separation processes of photo-generated charge carriers in the samples. The photoelectric ethanol sensing property induced by visible light for the ZnO/Ag 2 S heterostructure has been found, which should be valuable for the practical application of semiconductor gas sensors at room temperature.

A simple solution-phase approach to synthesize high quality ternary AgInSe2 and band gap tunable quaternary AgIn(S1-xSe x)2 nanocrystals

KAUST Repository

Bai, Tianyu

2014-01-01

A facile solution-phase route for the preparation of AgInSe2 nanocrystals was developed by using silver nitrate, indium stearate, and oleylamine-selenium (OAm-Se) as precursors. The evolution process of the AgInSe2 nanocrystals is discussed in detail and different reaction conditions all have a great impact on the growth and morphology of the nanocrystals. Alloyed AgIn(S1-xSex)2 nanocrystals with controlled composition across the entire range (0 ≤ x ≤ 1) was also successfully prepared by modulating the S/Se reactant mole ratio. X-ray diffraction (XRD), energy dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) were used to confirm that the alloyed AgIn(S1-xSex)2 nanocrystals are homogeneous. The UV-vis absorption spectra revealed that the band gap energies of the alloyed AgIn(S1-xSex)2 nanocrystals could be continuously tuned by increasing the Se content. © The Royal Society of Chemistry 2014.

Martensitic transformation behavior in Ti–Ni–X (Ag, In, Sn, Sb, Te, Tl, Pb, Bi) ternary alloys

Energy Technology Data Exchange (ETDEWEB)

Jang, Jai-young; Chun, Su-jin; Kim, Nam-suk; Cho, Jeung-won; Kim, Jae-hyun [School of Materials Science and Engineering, Gyeongsang National University, 900 Gazwadong, Jinju, Gyeongnam 660-701 (Korea, Republic of); Yeom, Jong-taek [Light Metal Division, Korea Institute of Materials Science (KIMS), Changwon 642-831 (Korea, Republic of); Kim, Jae-il [Materials Science and Engineering, University of Dong-A, Hadan-dong, Saha-gu, Busan 604-714 (Korea, Republic of); Nam, Tae-hyun, E-mail: tahynam@gnu.ac.kr [School of Materials Science and Engineering, Gyeongsang National University, 900 Gazwadong, Jinju, Gyeongnam 660-701 (Korea, Republic of)

2013-12-15

Graphical abstract: - Highlights: • Ag, In and Sn were soluble in TiNi matrix, while Sb, Te, Tl, Pb and Bi were not. • The B2-R-B19′transformation occurred in Ti-Ni-(Ag, In, Sn) alloys. • Solid solution hardening was essential for inducing the B2-R transformation. - Abstract: The microstructures and transformation behaviors of Ti–Ni–X (Ag, In, Sn, Sb, Te, Tl, Pb, Bi) ternary alloys were investigated using electron probe micro-analysis (EPMA), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and Micro Vickers hardness tests. All specimens consisted of Ti–Ni matrices and second phase particles. Ag, In and Sn were soluble in Ti–Ni matrices with a limited solubility (≤1.0 at%), while Sb, Te, Tl, Pb and Bi were not soluble. Two-stage B2-R-B19′ transformation occurred in Ti–48.8Ni–1.2Ag, Ti–49.0Ni–1.0In and Ti–49.0Ni–1.0Sn alloys, while one-stage B2-B19′ transformation occurred in Ti–49.0Ni–1.0Ag, Ti–49.0Ni–1.0Sb, Ti–49.0Ni–1.0Te, Ti–49.0Ni–1.0Pb and Ti–49.0Ni–1.0Bi alloys. Micro Vickers hardness of the alloys displaying the B2-R-B19′ transformation (Hv 250–368) was much larger than that (in Ti–Ni–X (X = non-transition elements) alloys.

Martensitic transformation behavior in Ti–Ni–X (Ag, In, Sn, Sb, Te, Tl, Pb, Bi) ternary alloys

International Nuclear Information System (INIS)

Jang, Jai-young; Chun, Su-jin; Kim, Nam-suk; Cho, Jeung-won; Kim, Jae-hyun; Yeom, Jong-taek; Kim, Jae-il; Nam, Tae-hyun

2013-01-01

Graphical abstract: - Highlights: • Ag, In and Sn were soluble in TiNi matrix, while Sb, Te, Tl, Pb and Bi were not. • The B2-R-B19′transformation occurred in Ti-Ni-(Ag, In, Sn) alloys. • Solid solution hardening was essential for inducing the B2-R transformation. - Abstract: The microstructures and transformation behaviors of Ti–Ni–X (Ag, In, Sn, Sb, Te, Tl, Pb, Bi) ternary alloys were investigated using electron probe micro-analysis (EPMA), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and Micro Vickers hardness tests. All specimens consisted of Ti–Ni matrices and second phase particles. Ag, In and Sn were soluble in Ti–Ni matrices with a limited solubility (≤1.0 at%), while Sb, Te, Tl, Pb and Bi were not soluble. Two-stage B2-R-B19′ transformation occurred in Ti–48.8Ni–1.2Ag, Ti–49.0Ni–1.0In and Ti–49.0Ni–1.0Sn alloys, while one-stage B2-B19′ transformation occurred in Ti–49.0Ni–1.0Ag, Ti–49.0Ni–1.0Sb, Ti–49.0Ni–1.0Te, Ti–49.0Ni–1.0Pb and Ti–49.0Ni–1.0Bi alloys. Micro Vickers hardness of the alloys displaying the B2-R-B19′ transformation (Hv 250–368) was much larger than that (< Hv 200) of the alloys displaying the B2-B19′ transformation. Solid solution hardening was an important factor for inducing the B2-R transformation in Ti–Ni–X (X = non-transition elements) alloys

Low-temperature solid-state preparation of ternary CdS/g-C3N4/CuS nanocomposites for enhanced visible-light photocatalytic H2-production activity

Science.gov (United States)

Cheng, Feiyue; Yin, Hui; Xiang, Quanjun

2017-01-01

Low-temperature solid-state method were gradually demonstrated as a high efficiency, energy saving and environmental protection strategy to fabricate composite semiconductor materials. CdS-based multiple composite photocatalytic materials have attracted increasing concern owning to the heterostructure constituents with tunable band gaps. In this study, the ternary CdS/g-C3N4/CuS composite photocatalysts were prepared by a facile and novel low-temperature solid-state strategy. The optimal ternary CdS/g-C3N4/CuS composite exhibits a high visible-light photocatalytic H2-production rate of 57.56 μmol h-1 with the corresponding apparent quantum efficiency reaches 16.5% at 420 nm with Na2S/Na2SO3 mixed aqueous solution as sacrificial agent. The ternary CdS/g-C3N4/CuS composites show the enhanced visible-light photocatalytic H2-evolution activity comparing with the binary CdS-based composites or simplex CdS. The enhanced photocatalytic activity is ascribed to the heterojunctions and the synergistic effect of CuS and g-C3N4 in promotion of the charge separation and charge mobility. This work shows that the low-temperature solid-state method is efficient and environmentally benign for the preparation of CdS-based multiple composite photocatalytic materials with enhanced visible-light photocatalytic H2-production activity.

Influence of layer compositions and annealing conditions on complete formation of ternary PdAgCu alloys prepared by sequential electroless and electroplating methods

Energy Technology Data Exchange (ETDEWEB)

Sumrunronnasak, Sarocha [Graduate Program of Petrochemistry and Polymer Science, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Tantayanon, Supawan, E-mail: supawan.t@chula.ac.th [Green Chemistry Research Laboratory, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Kiatgamolchai, Somchai [Department of Physics, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand)

2017-01-01

PdAgCu ternary alloy membranes were synthesized by the sequential electroless plating of Pd following by electroplating of Ag and Cu onto stainless steel substrate. The composition of the composite was varied by changing the deposition times. The fabricated layers were annealed at the temperatures between 500 and 600 °C for 20–60 h. The Energy Dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) were employed to investigate the element distribution in the membrane which provided the insight on membrane alloying process. Complete formation of the alloy could be obtained when the Pd composition was greater than a critical value of 60 wt%, and Ag and Cu contents were in the range of 18–30 wt% and 2–13 wt%, respectively. Deposition times of Ag and Cu were found to affect the completion of alloy formation. Excess amount of the deposited Cu particularly tended to segregate on the surface of the membrane. - Highlights: • Ternary PdAgCu alloy membranes were successfully prepared by the sequential electroless and electroplating methods. • The average Pd composition required to form alloy was found to be approximately at least 60%wt. • The alloy region was achieved for f Pd 60–73 wt%, Cu 18–30 wt% and Ag 2–13 wt%. • Suitable annealing temperature in the range of 500–600 °C for an adequate period of treating time (20–60 h).

Crystal Growth of Ternary Compound Semiconductors in Low Gravity Environment

Science.gov (United States)

Su, Ching-Hua

2014-01-01

A low gravity material experiment will be performed in the Material Science Research Rack (MSRR) on International Space Station (ISS). There are two sections of the flight experiment: (I) crystal growth of ZnSe and related ternary compounds, such as ZnSeS and ZnSeTe, by physical vapor transport (PVT) and (II) melt growth of CdZnTe by directional solidification. The main objective of the project is to determine the relative contributions of gravity-driven fluid flows to the compositional distribution, incorporation of impurities and defects, and deviation from stoichiometry observed in the grown crystals as results of buoyancy-driven convection and growth interface fluctuations caused by irregular fluid-flows on Earth. The investigation consists of extensive ground-based experimental and theoretical research efforts and concurrent flight experimentation. This talk will focus on the ground-based studies on the PVT crystal growth of ZnSe and related ternary compounds. The objectives of the ground-based studies are (1) obtain the experimental data and conduct the analyses required to define the optimum growth parameters for the flight experiments, (2) perfect various characterization techniques to establish the standard procedure for material characterization, (3) quantitatively establish the characteristics of the crystals grown on Earth as a basis for subsequent comparative evaluations of the crystals grown in a low-gravity environment and (4) develop theoretical and analytical methods required for such evaluations. ZnSe and related ternary compounds have been grown by vapor transport technique with real time in-situ non-invasive monitoring techniques. The grown crystals have been characterized extensively by various techniques to correlate the grown crystal properties with the growth conditions.

Construction of RGO/CdIn2S4/g-C3N4 ternary hybrid with enhanced photocatalytic activity for the degradation of tetracycline hydrochloride

Science.gov (United States)

Xiao, Peng; Jiang, Deli; Ju, Lixin; Jing, Junjie; Chen, Min

2018-03-01

Although RGO shows great advantage in promoting charge separation and transfer of semiconductor, construction of an efficient RGO-incorporated photocatalyst is still challenging. Herein, RGO was employed to construct novel RGO/CdIn2S4/g-C3N4 (donated as RGO/CIS/CN) ternary photocatalyst by a facile hydrothermal method for the degradation of tetracycline hydrochloride (TC). The RGO/CIS/CN ternary photocatalyst showed significantly enhanced photocatalytic activity towards the degradation of TC as compared to the binary CIS/CN, CIS/CN, and CN/RGO. The photoluminescence and photocurrent response results indicate that this enhanced photocatalytic activity can be mainly ascribed to the improved charge separation and transfer efficiency. Based on the radical trapping and electron spin resonance results, the superoxide radicals and holes are proposed to play an important role in the degradation of TC over RGO/CIS/CN ternary photocatalyst. This work paves new opportunities for the synthesis of RGO-incorporated ternary photocatalyst as an efficient photocatalyst for the degradation of organic contaminant.

Mechanical properties of some binary, ternary and quaternary III-V compound semiconductor alloys

International Nuclear Information System (INIS)

Navamathavan, R.; Arivuoli, D.; Attolini, G.; Pelosi, C.; Choi, Chi Kyu

2007-01-01

Vicker's microindentation tests have been carried out on InP/InP, GaAs/InP, InGaAs/InP and InGaAsP/InP III-V compound semiconductor alloys. The detailed mechanical properties of these binary, ternary and quaternary epilayers were determined from the indentation experiments. Microindentation studies of (1 1 1) GaAs/InP both A and B faces show that the hardness value increases with load and attains a constant for further increase in load and the microhardness values were found to lie between 3.5 and 4.0 GPa. The microhardness values of InGaAs/InP epilayers with different thickness were found to lie between 3.93 and 4.312 GPa. The microhardness values of InGaAsP/InP with different elemental composition were found to lie between 5.08 and 5.73 GPa. The results show that the hardness of the quaternary alloy drastically increases, the reason may be that the increase in As concentration hardens the lattice when phosphorous concentration is less and hardness decreases when phosphorous is increased. It was interestingly observed that the hardness value increases as we proceed from binary to quaternary III-V compound semiconductor alloys

Thermodynamic analysis and phase equilibria investigation in Pb−Zn−Ag system

Directory of Open Access Journals (Sweden)

Mitovski Aleksandra M.

2010-01-01

Full Text Available Physico-chemical processes that take place during the refining process in the extractive metallurgy of lead, are connected with ternary Pb−Zn−Ag system, which is necessary to study from the theoretical practical and aspects. Such investigation is important from production point of view, because of the phenomena that occur during desilvering of lead which is one of the important stages during lead refining process. Process of lead desilvering binds to ternary system Pb−Zn−Ag, which was the reason for numerous investigations, both from thermodynamic point of view and in terms of testing and determining the phase diagram, bearing in mind the theoretical, and practical importance of knowledge about the processes which are going in investigated system. The paper presents the results of thermodynamic analysis and investigation of phase equilibria of the Pb−Zn−Ag ternary system using the method of thermodynamic predictions and phase diagrams calculations, respectively, and the experimental results of metalography obtained by optical microscopy. Phase diagram of the vertical section Pb−Zn80Ag20 is presented, obtained by CALPHAD calculation methodology, and using PANDAT thermodynamic software, compared to experimental results obtained by DTA analysis. The results show a pronounced break in solubility, which is characteristic for the whole ternary Pb−Zn−Ag system. Also, it can be noticed that the thermodynamic properties follow the behavior of this system, which is expressed through positive deviation of Raoult’s law, pointing to the lack of lead affinity compared to the other two components in the system. The optical microscopy results of the investigated system show the following: - Sample L1 (weight% Pb = 98: the structure of the observed section shows double eutectic (Pbsol+Zn−Agsol which lies in the base of the primary crystals of lead (Pbsol - Samples L2−L5: the structure consists of a dual eutectic (Pbsol+Zn−Agsol and

Ternary g-C{sub 3}N{sub 4}/ZnO/AgCl nanocomposites: Synergistic collaboration on visible-light-driven activity in photodegradation of an organic pollutant

Energy Technology Data Exchange (ETDEWEB)

Akhundi, Anise; Habibi-Yangjeh, Aziz, E-mail: ahabibi@uma.ac.ir

2015-12-15

Graphical abstract: - Highlights: • Novel ternary g-C{sub 3}N{sub 4}/ZnO/AgCl nanocomposites were prepared using a facile method. • g-C{sub 3}N{sub 4}/ZnO/AgCl (40%) has superior activity in degradation of RhB under visible-light. • The activity is 7.5 and 6-fold higher than g-C{sub 3}N{sub 4}/ZnO and g-C{sub 3}N{sub 4}/AgCl, respectively. • There are synergistic collaboration between ZnO and AgCl in enhancing the activity. - Abstract: The present work demonstrates the preparation of ternary g-C{sub 3}N{sub 4}/ZnO/AgCl nanocomposites, as novel visible-light-driven photocatalysts, using a facile large-scale methodology. The microstructure, morphology, purity, thermal, and spectroscopic properties of the prepared samples were studied using XRD, TEM, EDX, TG, UV–vis DRS, FT-IR, and PL techniques. Compared with the g-C{sub 3}N{sub 4}/ZnO and g-C{sub 3}N{sub 4}/AgCl nanocomposites, the g-C{sub 3}N{sub 4}/ZnO/AgCl nanocomposites displayed higher photocatalytic activity for degradation of rhodamine B under visible-light irradiation. Photocatalytic activity of the g-C{sub 3}N{sub 4}/ZnO/AgCl (40%) nanocomposite is about 9.5, 7.5, and 6-fold higher than those of the g-C{sub 3}N{sub 4}, g-C{sub 3}N{sub 4}/ZnO, and g-C{sub 3}N{sub 4}/AgCl samples, respectively. The enhanced photocatalytic activity of the nanocomposites was mainly attributed to efficiently separation of the charge carriers by synergistic collaboration of ZnO and AgCl in removing photogenerated electrons from g-C{sub 3}N{sub 4}. Furthermore, the results showed that the photocatalytic activity of the nanocomposite considerably depends on the preparation time, calcination temperature, and scavengers of the reactive species. Finally, the nanocomposite was found to be a reusable photocatalyst.

Fabrication of Ternary AgPdAu Alloy Nanoparticles on c-Plane Sapphire by the Systematical Control of Film Thickness and Deposition Sequence

Science.gov (United States)

Kunwar, Sundar; Pandey, Puran; Sui, Mao; Bastola, Sushil; Lee, Jihoon

2018-06-01

In this work, a systematic study on the fabrication of ternary AgPdAu alloy nanoparticles (NPs) on c-plane sapphire (0001) is presented and the corresponding structural and optical characteristics are demonstrated. The metallic trilayers of various thicknesses and deposition orders are annealed in a controlled manner (400 °C to 900 °C) to induce the solid-state dewetting that yields the various structural configurations of AgPdAu alloy NPs. The dewetting of relatively thicker trilayers (15 nm) is gradually progressed with void nucleation, growth, and coalescence, isolated NP formation, and shape transformation, along with the temperature control. For 6 nm thickness, owing to the sufficient dewetting of trilayers along with enhanced diffusion, dense and small spherical alloy NPs are fabricated. Depending on the specific growth condition, the surface diffusion and interdiffusion of metal atoms, surface and interface energy minimization, Rayleigh instability, and equilibrium configuration are correlated to describe the fabrication of ternary alloy NPs. Ternary alloy NPs exhibit morphology-dependent ultraviolet-visible-near infrared (UV-VIS-NIR) reflectance properties such as the inverse relationship of average reflectance with the surface coverage, absorption enhancement in specific regions, and reflectance maxima in UV and NIR regions. In addition, Raman spectra depict the six active phonon modes of sapphires and their intensity and position modulation by the alloy NPs.

Photoreduction of Ag{sup +} in Ag/Ag{sub 2}S/Au memristor

Energy Technology Data Exchange (ETDEWEB)

Mou, N.I.; Tabib-Azar, M., E-mail: azar.m@utah.edu

2015-06-15

Highlights: • The effect of illumination on the operating voltages and switching speed of Ag/Ag{sub 2}S/Au memristors is studied • Illumination decreased the average switching time from high to low resistance states by ∼19% and decreased the turn-off voltages dramatically from −0.8 V to −0.25 V. • Photo-induced reduction of silver in Ag{sub 2}S may be used in three dimensional optical memories that can be electronically read and reset. • Illumination changed sulfur's valency and modified its oxidation/reduction potential. - Abstract: Silver halides and chalcogenides are excellent memristor materials that have been extensively used in the past as photosensitive layers in photography. Here we examine the effect of illumination on the operating voltages and switching speed of Ag/Ag{sub 2}S/Au memristors using a green laser (473–523 nm). Our results indicate that illumination decreases the average switching time from high to low resistance states by ∼19% and decreases the turn-off voltages dramatically from −0.8 V to −0.25 V that we attribute to the change in sulfur valency and a photo-induced change in its oxidation/reduction potential. Photo-induced reduction of silver in Ag{sub 2}S may be used in three dimensional optical memories that can be electronically read and reset.

Graphene oxide reinforced core-shell structured Ag@Cu2O with tunable hierarchical morphologies and their morphology-dependent electrocatalytic properties for bio-sensing applications.

Science.gov (United States)

Gan, Tian; Wang, Zhikai; Shi, Zhaoxia; Zheng, Dongyun; Sun, Junyong; Liu, Yanming

2018-07-30

In this study, a facile solution approach was developed for the synthesis of a series of core-shell structured Ag@Cu 2 O nanocrystals of various shapes including triangles, spheres, and cubes with well-defined stable heterojunctions. The electrooxidation of dopamine (DA), uric acid (UA), guanine (G), and adenine (A) using these hybrids revealed morphology-dependent sensing properties, with activities and accumulation ability following the order, triangular Ag@Cu 2 O > spherical Ag@Cu 2 O > cubic Ag@Cu 2 O. Further, we constructed a novel graphene oxide (GO) nanosheet-reinforced triangular Ag@Cu 2 O ternary hetero-nanostructure. Such a hybrid with a three-dimensional interconnected hierarchical architecture is suitable for catalysis, since it not only leads to improved interfacial electron transfer, but also readily exposes the highly catalytic Ag@Cu 2 O to the reactants. Therefore, more enhanced electrochemical activities were observed for the oxidation of DA, UA, G, and A. This study provides an efficient way to synthesize morphology-controlled Ag@Cu 2 O heterogeneous catalysts for the fabrication of potential biosensors, and also opens up attractive avenues in the design of multifunctional ternary noble metal-semiconductor-carbon hybrids. Copyright © 2018 Elsevier B.V. All rights reserved.

Acceptors in II-IV Semiconductors - Incorporation and Complex Formation

CERN Multimedia

2002-01-01

A strong effort is currently devoted to the investigation of defects and the electrical activation of dopant atoms in II-VI semiconductors. In particular, the knowledge about the behaviour of acceptors, prerequisite for the fabrication of p-type semiconductors, is rather limited. The perturbed $\\,{\\gamma\\gamma}$ -angular correlation technique (PAC) and the photoluminescence spectroscopy (PL) using the radioactive isotopes $^{77}\\!$Br and $^{111}\\!$Ag will be applied for investigating the behaviour of acceptor dopant atoms and their interactions with defects in II-VI semiconductors. The main topic will be the identification of the technical conditions for the incorporation of electrically active acceptors in the II-VI semiconductors ~ZnS, ZnSe, ZnTe, CdS, CdSe, and CdTe with particular emphasis on the compounds~ CdTe, ZnSe, and ZnTe. The investigations will be supplemented by first exploratory PL experiments with the group V acceptors $^{71}\\!$As and $^{121}\\!$Sb. With help of the probe $^{111}\\!$Ag, the pos...

Synthesis of biocompatible AuAgS/Ag2S nanoclusters and their applications in photocatalysis and mercury detection

International Nuclear Information System (INIS)

Zhao, Qian; Chen, Shenna; Zhang, Lingyang; Huang, Haowen; Liu, Fengping; Liu, Xuanyong

2014-01-01

In this paper, a facile approach for preparation of AuAgS/Ag 2 S nanoclusters was developed. The unique AuAgS/Ag 2 S nanoclusters capped with biomolecules exhibit interesting excellent optical and catalytic properties. The fluorescent AuAgS/Ag 2 S nanoclusters show tunable luminescence depending on the nanocluster size. The apoptosis assay demonstrated that the AuAgS/Ag 2 S nanoclusters showed low cytotoxicity and good biocompatibility. Therefore, the nanoclusters can be used not only as a probe for labeling cells but also for their photocatalytic activity for photodegradation of organic dye. Moreover, a highly selective and sensitive assay for detection of mercury including Hg 2+ and undissociated mercury complexes was developed based on the quenching fluorescent AuAgS/Ag 2 S nanoclusters, which provides a promising approach for determining various forms of Hg in the mercury-based compounds in environment. These unique nanoclusters may have potential applications in biological labeling, sensing mercury, and photodegradation of various organic pollutants in waste water.Graphical Abstract

Design of ternary clocked adiabatic static random access memory

International Nuclear Information System (INIS)

Wang Pengjun; Mei Fengna

2011-01-01

Based on multi-valued logic, adiabatic circuits and the structure of ternary static random access memory (SRAM), a design scheme of a novel ternary clocked adiabatic SRAM is presented. The scheme adopts bootstrapped NMOS transistors, and an address decoder, a storage cell and a sense amplifier are charged and discharged in the adiabatic way, so the charges stored in the large switch capacitance of word lines, bit lines and the address decoder can be effectively restored to achieve energy recovery during reading and writing of ternary signals. The PSPICE simulation results indicate that the ternary clocked adiabatic SRAM has a correct logic function and low power consumption. Compared with ternary conventional SRAM, the average power consumption of the ternary adiabatic SRAM saves up to 68% in the same conditions. (semiconductor integrated circuits)

Single-particle spectroscopy of I-III-VI semiconductor nanocrystals: spectral diffusion and suppression of blinking by two-color excitation.

Science.gov (United States)

Sharma, Dharmendar Kumar; Hirata, Shuzo; Bujak, Lukasz; Biju, Vasudevanpillai; Kameyama, Tatsuya; Kishi, Marino; Torimoto, Tsukasa; Vacha, Martin

2016-07-14

Ternary I-III-VI semiconductor nanocrystals have been explored as non-toxic alternatives to II-VI semiconductors for optoelectronic and sensing applications, but large photoluminescence spectral width and moderate brightness restrict their practical use. Here, using single-particle photoluminescence spectroscopy on nanocrystals of (AgIn)xZn2(1-x)S2 we show that the photoluminescence band is inhomogeneously broadened and that size distribution is the dominant factor in the broadening. The residual homogeneous linewidth of individual nanocrystals reaches up to 75% of the ensemble spectral width. Single nanocrystals undergo spectral diffusion which also contributes to the inhomogeneous band. Excitation with two lasers with energies above and below the bandgap reveals coexistence of two emitting donor states within one particle. Spectral diffusion in such particles is due to temporal activation and deactivation of one such state. Filling of a trap state with a lower-energy laser enables optical modulation of photoluminescence intermittency (blinking) and leads to an almost two-fold increase in brightness.

Identification of Ag-acceptors in $^{111}Ag^{111}Cd$ doped ZnTe and CdTe

CERN Document Server

Hamann, J; Deicher, M; Filz, T; Lany, S; Ostheimer, V; Strasser, F; Wolf, H; Wichert, T

2000-01-01

Nominally undoped ZnTe and CdTe crystals were implanted with radioactive /sup 111/Ag, which decays to /sup 111/Cd, and investigated by photoluminescence spectroscopy (PL). In ZnTe, the PL lines caused by an acceptor level at 121 meV are observed: the principal bound exciton (PBE) line, the donor-acceptor pair (DAP) band, and the two-hole transition lines. In CdTe, the PBE line and the DAP band that correspond to an acceptor level at 108 meV appear. Since the intensities of all these PL lines decrease in good agreement with the half-life of /sup 111/Ag of 178.8 h, both acceptor levels are concluded to be associated with defects containing a single Ag atom. Therefore, the earlier assignments to substitutional Ag on Zn- and Cd-lattice sites in the respective II-VI semiconductors are confirmed. The assignments in the literature of the S/sub 1/, S /sub 2/, and S/sub 3/ lines in ZnTe and the X/sub 1//sup Ag/, X/sub 2 //sup Ag//C/sub 1//sup Ag/, and C/sub 2//sup Ag/ lines in CdTe to Ag- related defect complexes are ...

Chemically deposited In2S3–Ag2S layers to obtain AgInS2 thin films by thermal annealing

International Nuclear Information System (INIS)

Lugo, S.; Peña, Y.; Calixto-Rodriguez, M.; López-Mata, C.; Ramón, M.L.; Gómez, I.; Acosta, A.

2012-01-01

Highlights: ► We obtained polycrystalline silver indium sulfide thin films through the annealing of chemically deposited In 2 S 3 –Ag 2 S films. ► According to XRD chalcopyrite structure of AgInS 2 was obtained. ► AgInS 2 thin film has a band gap of 1.86 eV and a conductivity value of 1.2 × 10 −3 (Ω cm) −1 . - Abstract: AgInS 2 thin films were obtained by the annealing of chemical bath deposited In 2 S 3 –Ag 2 S layers at 400 °C in N 2 for 1 h. According to the XRD and EDX results the chalcopyrite structure of AgInS 2 has been obtained. These films have an optical band gap, E g , of 1.86 eV and an electrical conductivity value of 1.2 × 10 −3 (Ω cm) −1 .

Structural Characterization of AgGaS2-type Photocatalysts for Hydrogen Production from Water Under Visible Light

International Nuclear Information System (INIS)

Choi, Sun Hee; Shin, Namsoo; Jang, Jum Suk; Lee, Jae Sung

2007-01-01

Bulky AgGaS2 was synthesized as a p-type semiconductor photocatalyst by a conventional solid state reaction under N2 flow for hydrogen production under visible light. To remove the impurity phase involved in the synthesized material and improve its crystallinity, the material was treated at various temperatures of 873-1123 K under H2S flow. Impurity phases were identified as β-Ga2O3 and Ag9GaS6 with Rietveld analysis of XRD, and the local coordination structure around gallium atom in AgGaS2 was investigated by EXAFS. As the H2S-treatment temperature increased, the contribution from impurity phase was diminished. When the temperature reached 1123 K, the impurity phases were completely removed and the material showed the highest photocatalytic activity

Low-temperature solid-state preparation of ternary CdS/g-C_3N_4/CuS nanocomposites for enhanced visible-light photocatalytic H_2-production activity

International Nuclear Information System (INIS)

Cheng, Feiyue; Yin, Hui; Xiang, Quanjun

2017-01-01

Highlights: • CdS/g-C_3N_4/CuS composite were synthesized by low-temperature solid-state method. • CdS/g-C_3N_4/CuS show enhanced visible-light photocatalytic H_2 evolution activity. • The enhanced photocatalytic H_2 production activity is due to the heterojunction. • Heterojunction between the components promote charge separation/transfer property. - Abstract: Low-temperature solid-state method were gradually demonstrated as a high efficiency, energy saving and environmental protection strategy to fabricate composite semiconductor materials. CdS-based multiple composite photocatalytic materials have attracted increasing concern owning to the heterostructure constituents with tunable band gaps. In this study, the ternary CdS/g-C_3N_4/CuS composite photocatalysts were prepared by a facile and novel low-temperature solid-state strategy. The optimal ternary CdS/g-C_3N_4/CuS composite exhibits a high visible-light photocatalytic H_2-production rate of 57.56 μmol h"−"1 with the corresponding apparent quantum efficiency reaches 16.5% at 420 nm with Na_2S/Na_2SO_3 mixed aqueous solution as sacrificial agent. The ternary CdS/g-C_3N_4/CuS composites show the enhanced visible-light photocatalytic H_2-evolution activity comparing with the binary CdS-based composites or simplex CdS. The enhanced photocatalytic activity is ascribed to the heterojunctions and the synergistic effect of CuS and g-C_3N_4 in promotion of the charge separation and charge mobility. This work shows that the low-temperature solid-state method is efficient and environmentally benign for the preparation of CdS-based multiple composite photocatalytic materials with enhanced visible-light photocatalytic H_2-production activity.

Scattering amplitudes and static atomic correction factors for the composition-sensitive 002 reflection in sphalerite ternary III-V and II-VI semiconductors.

Science.gov (United States)

Schowalter, M; Müller, K; Rosenauer, A

2012-01-01

Modified atomic scattering amplitudes (MASAs), taking into account the redistribution of charge due to bonds, and the respective correction factors considering the effect of static atomic displacements were computed for the chemically sensitive 002 reflection for ternary III-V and II-VI semiconductors. MASAs were derived from computations within the density functional theory formalism. Binary eight-atom unit cells were strained according to each strain state s (thin, intermediate, thick and fully relaxed electron microscopic specimen) and each concentration (x = 0, …, 1 in 0.01 steps), where the lattice parameters for composition x in strain state s were calculated using continuum elasticity theory. The concentration dependence was derived by computing MASAs for each of these binary cells. Correction factors for static atomic displacements were computed from relaxed atom positions by generating 50 × 50 × 50 supercells using the lattice parameter of the eight-atom unit cells. Atoms were randomly distributed according to the required composition. Polynomials were fitted to the composition dependence of the MASAs and the correction factors for the different strain states. Fit parameters are given in the paper.

Atomistic study of ternary oxides as high-temperature solid lubricants

Science.gov (United States)

Gao, Hongyu

Friction and wear are important tribological phenomena tightly associated with the performance of tribological components/systems such as bearings and cutting machines. In the process of contact and sliding, friction and wear lead to energy loss, and high friction and wear typically result in shortened service lifetime. To reduce friction and wear, solid lubricants are generally used under conditions where traditional liquid lubricants cannot be applied. However, it is challenging to maintain the functionality of those materials when the working environment becomes severe. For instance, at elevated temperatures (i.e., above 400 °C), most traditional solid lubricants, such as MoS2 and graphite, will easily oxidize or lose lubricity due to irreversible chemical changes. For such conditions, it is necessary to identify materials that can remain thermally stable as well as lubricious over a wide range of temperatures. Among the currently available high-temperature solid lubricants, Ag-based ternary metal oxides have recently drawn attention due to their low friction and ability to resist oxidation. A recent experimental study showed that the Ag-Ta-O ternary exhibited an extremely low coefficient of friction (0.06) at 750 °C. To fully uncover the lubricious nature of this material as a high-temperature solid lubricant, a series of tribological investigations were carried out based on one promising candidate - silver tantalate (AgTaO3). The study was then extended to alternative materials, Cu-Ta-O ternaries, to accommodate a variety of application requirements. We aimed to understand, at an atomic level, the effects of physical and chemical properties on the thermal, mechanical and tribological behavior of these materials at high temperatures. Furthermore, we investigated potassium chloride films on a clean iron surface as a representative boundary lubricating system in a nonextreme environment. This investigation complemented the study of Ag/Cu-Ta-O and enhanced the

Ag3PO4-TiO2-Graphene Oxide Ternary Composites with Efficient Photodegradation, Hydrogen Evolution, and Antibacterial Properties

Directory of Open Access Journals (Sweden)

Fu-Jye Sheu

2018-02-01

Full Text Available Ag3PO4-TiO2-graphene oxide ternary composite photocatalysts were fabricated by the photocatalytic reduction and ion exchange methods. The properties and photocatalytic activity of the composites were examined, and the photodegradation mechanism was investigated. More TiO2 nanoparticles in the composites were found to improve light absorption, but caused a larger impedance and inferior charge transport. Excess TiO2 nanoparticles distributed over the surfaces of Ag3PO4 and graphene oxide decreased the specific surface area and thus lowered light absorbance. An appropriate TiO2 content enhanced photocatalytic performance. When the molar ratio of Ag3PO4 to TiO2 was 0.6, the highest efficiency in photodegradation, hydrogen production (with a quantum efficiency of 8.1% and a hydrogen evolution rate of 218.7 μmole·g−1·h−1 and bacterial inactivation was achieved. Trapping experiments demonstrated that superoxide radicals and holes are the major active species involved in the photodegradation process.

Synthesis and characterization of thermally evaporated Cu2SnSe3 ternary semiconductor

Science.gov (United States)

Hamdani, K.; Chaouche, M.; Benabdeslem, M.; Bechiri, L.; Benslim, N.; Amara, A.; Portier, X.; Bououdina, M.; Otmani, A.; Marie, P.

2014-11-01

Copper Tin Selenide (CuSnSe) powder was mechanically alloyed by high energy planetary ball milling, starting from elemental powders. Synthesis time and velocity have been optimized to produce Cu2SnSe3 materials. Thin films were prepared by thermal evaporation on Corning glass substrate at Ts = 300 °C. The structural, compositional, morphological and optical properties of the synthesized semiconductor have been analyzed by X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), scanning electron microscopy (SEM) and transmission electron microscopy. The analyzed powder exhibited a cubic crystal structure, with the presence of Cu2Se as a secondary phase. On the other hand, the deposited films showed a cubic Cu2SnSe3 ternary phase and extra peaks belonging to some binary compounds. Furthermore, optical measurements showed that the deposited layers have a relatively high absorption coefficient of 105 cm-1 and present a band gap of 0.94 eV.

Synthesis and Characterization of the Ternary Thiobismuthates A9Bi13S24 (A = K, Rb)

KAUST Repository

Davaasuren, Bambar

2016-11-16

Ternary alkali metal thiobismuthates ABiS (A = K, Rb) were synthesized by direct combination reactions at 650 °C. The compounds crystallize in the monoclinic space group C2/m (no. 12) with cell parameters a = 30.919(1) Å, b = 4.1008(2) Å, c = 20.9072(9) Å, β = 105.826(3)° for KBiS (1) and a = 31.823(6) Å, b = 4.1177(8) Å, c = 21.086(4) Å, β = 105.62(3)° for RbBiS (2). The crystal structure of 1 contains a 3D [KBiS] polyanionic framework, whereas 2 consists of 2D [RbBiS] polyanionic slabs stacked along [201]. Both 1 and 2 are semiconductors with a band gap of 1.4 and 1.3 eV, respectively, which is supported by an electronic structure calculation. 1 melts congruently at 580 °C, while 2 melts incongruently at 575 °C. 1 and 2 are airstable and insoluble in water and organic solvents.

Design of ternary low-power Domino JKL flip—flop and its application

International Nuclear Information System (INIS)

Wang Pengjun; Yang Qiankun; Zheng Xuesong

2012-01-01

By researching the ternary flip—flop and the adiabatic Domino circuit, a novel design of low-power ternary Domino JKL flip—flop on the switch level is proposed. First, the switch-level structure of the ternary adiabatic Domino JKL flip—flop is derived according to the switch-signal theory and its truth table. Then the ternary loop operation circuit and ternary reverse loop operation circuit are achieved by employing the ternary JKL flip—flop. Finally, the circuit is simulated by using the Spice tool and the results show that the logic function is correct. The energy consumption of the ternary adiabatic Domino JKL flip—flop is 69% less than its conventional Domino counterpart. (semiconductor integrated circuits)

Facile synthesis, structure, and properties of Ag{sub 2}S/Ag heteronanostructure

Energy Technology Data Exchange (ETDEWEB)

Sadovnikov, S. I., E-mail: sadovnikov@ihim.uran.ru; Gusev, A. I. [Ural Branch of the Russian Academy of Sciences, Institute of Solid State Chemistry (Russian Federation)

2016-09-15

Ag{sub 2}S/Ag heteronanostructure has been produced by a simple one-stage chemical deposition from aqueous solutions of silver nitrate, sodium sulfide, and sodium citrate with the use of monochromatic light irradiation. For simultaneous synthesis of Ag{sub 2}S and Ag nanoparticles, deposition has been performed from reaction mixtures with reduced sodium sulfide concentration. The size of Ag{sub 2}S and Ag nanoparticles is 45–50 and 15–20 nm, respectively. It is established that in the contact layer between silver sulfide and silver, nonconducting α-Ag{sub 2}S acanthite transforms into superionic β-Ag{sub 2}S argentite under the action of external electric field. The scheme of the operation of a resistive switch based on an Ag{sub 2}S/Ag heteronanostructure is proposed. The UV–Vis optical absorption spectra of colloidal solutions of Ag{sub 2}S/Ag heteronanostructures have been studied.Graphical Abstract.

Thermochemical properties of silver tellurides including empressite (AgTe) and phase diagrams for Ag-Te and Ag-Te-O

Science.gov (United States)

Voronin, Mikhail V.; Osadchii, Evgeniy G.; Brichkina, Ekaterina A.

2017-10-01

This study compiles original experimental and literature data on the thermodynamic properties (ΔfG°, S°, ΔfH°) of silver tellurides (α-Ag2Te, β-Ag2Te, Ag1.9Te, Ag5Te3, AgTe) obtained by the method of solid-state galvanic cell with the RbAg4I5 and AgI solid electrolytes. The thermodynamic data for empressite (AgTe, pure fraction from Empress Josephine Mine, Colorado USA) have been obtained for the first time by the electrochemical experiment with the virtual reaction Ag + Te = AgTe. The Ag-Te phase diagrams in the T - x and log fTe2 (gas) - 1/ T coordinates have been refined, and the ternary Ag-Te-O diagrams with Ag-Te-TeO2 (paratellurite) composition range have been calculated.

Simultaneous determination of Hg(II)-Ag(I)-Cd(II) by conductometric titration using the formation of ternary complex

International Nuclear Information System (INIS)

Hayashida, Ichiro; Yoshida, Hitoshi; Taga, Mitsuhiko; Hikime, Seiichiro

1979-01-01

A conductometric determination of Hg(II), Ag(I) and Cd(II) was carried out by using the insoluble ternary complex formation of the metal ions with iodide ion in the presence of 1,10-phenanthroline (phen). Recommended procedure is as follows; An aliquot of sample solution containing (14 -- 29) mg of Hg(II), (8 -- 16) mg of Ag(I), and (9 -- 17) mg of Cd(II) transfered into a 100 ml beaker. Add to acetate buffer and stoichiometric amounts of phen (40% ethanol-water solution). Amounts of nitrate ion which was estimated separately by other titration with 0.1 M Ag(phen) 2 complex (40% ethanol-water solution) are adjusted in the range of (4.0 -- 6.0) mM. The sample solution is titrated with 0.1 M KI standard solution at the rate of 0.20 ml/min or less. The titration curve showed three end-points corresponding to the formation of (1) Hg(phen) 2 I 2 , (2) Ag(phen)I, and (3) Cd(phen) 2 I 2 . The relative standard deviation was less than 0.8%, when the pH value was controlled at 4.0 -- 4.5 (acetate buffer) and the nitrate concentration was adjusted in the range of (4.0 -- 6.0)mM. The effect of diverse ions on the determination was also investigated in detail. (author)

The negative temperature coefficient resistivities of Ag2S-Ag core–shell structures

International Nuclear Information System (INIS)

Yu, Mingming; Liu, Dongzhi; Li, Wei; Zhou, Xueqin

2014-01-01

In this paper, the conductivity of silver nanoparticle films protected by 3-mercaptopropionic acid (Ag/MPA) has been investigated. When the nanoparticles were annealed in air at 200 °C, they converted to stable Ag 2 S-Ag core–shell structures. The mechanism for the formation of the Ag 2 S-Ag core–shell structures along with the compositional changes and the microstructural evolution of the Ag/MPA nanoparticles during the annealing process are discussed. It is proposed that the Ag 2 S-Ag core–shell structure was formed through a solid-state reduction reaction, in which the Ag + ions coming from Ag 2 S were reduced by sulfonate species and sulfur ions. The final Ag 2 S-Ag films display an exponentially decreased resistivity with increasing temperature from 25 to 170 °C. The negative temperature coefficient resistivity of Ag 2 S-Ag films can be adjusted by changing the S/Ag molar ratio used for the synthesis of the Ag/MPA nanoparticles, paving the way for the preparation of negative temperature-coefficient thermistors via printing technology for use in the electronics.

Evolution of Ternary AuAgPd Nanoparticles by the Control of Temperature, Thickness, and Tri-Layer

Directory of Open Access Journals (Sweden)

Sundar Kunwar

2017-11-01

Full Text Available Metallic alloy nanoparticles (NPs possess great potential to enhance the optical, electronic, chemical, and magnetic properties for various applications by the control of morphology and elemental composition. This work presents the fabrication of ternary AuAgPd alloy nanostructures on sapphire (0001 via the solid-state dewetting of sputter-deposited tri-metallic layers. Based on the systematic control of temperature, thickness, and deposition order of tri-layers, the composite AuAgPd alloy nanoparticles (NPs with various shape, size, and density are demonstrated. The metallic tri-layers exhibit various stages of dewetting based on the increasing growth temperatures between 400 and 900 °C at 15 nm tri-layer film thickness. Specifically, the nucleation of tiny voids and hillocks, void coalescence, the growth and isolated nanoparticle formation, and the shape transformation with Ag sublimation are observed. With the reduced film thickness (6 nm, tiny alloy NPs with improved structural uniformity and spatial arrangement are obtained due to enhanced dewetting. The growth trend of alloy NPs is drastically altered by changing the deposition order of metallic tri-layers. The overall evolution is governed by the surface diffusion and inter-mixing of metallic atoms, Rayleigh-like instability, surface and interface energy minimization, and equilibrium state of the system. The UV-VIS-NIR reflectance spectra reveal the formation of an absorption band and reflectance maxima at specific wavelengths based on the morphology and composition of AuAgPd alloy NPs. In addition, Raman spectra analysis shows the modulation of intensity and peak position of natural vibration modes of sapphire (0001.

Ternary magnetic g-C{sub 3}N{sub 4}/Fe{sub 3}O{sub 4}/AgI nanocomposites: Novel recyclable photocatalysts with enhanced activity in degradation of different pollutants under visible light

Energy Technology Data Exchange (ETDEWEB)

Akhundi, Anise; Habibi-Yangjeh, Aziz, E-mail: ahabibi@uma.ac.ir

2016-05-01

In the present work, we illustrate the preparation of graphitic carbon nitride/magnetite/silver iodide (g-C{sub 3}N{sub 4}/Fe{sub 3}O{sub 4}/AgI) nanocomposites, as novel magnetically recyclable visible-light-driven photocatalysts. The nanocomposites were prepared by reflux method at 96 °C with no require to any additives or post preparation treatments. The resultant samples were characterized using XRD, EDX, SEM, TEM, FT-IR, UV–vis DRS, PL, TGA, and VSM techniques. Among the nanocomposites, the sample with 20 percent of AgI displayed superior activity. This nanocomposite exhibited superparamagnetic property with a saturation magnetization of 16.9 emu/g. Photocatalytic activity of the g-C{sub 3}N{sub 4}/Fe{sub 3}O{sub 4}/AgI (20%) nanocomposite was about 8.7 and 6.9 fold higher than those of the g-C{sub 3}N{sub 4} and g-C{sub 3}N{sub 4}/Fe{sub 3}O{sub 4} samples, respectively for degradation of rhodamine B (RhB) under visible-light irradiation. Moreover, we investigated the influence of refluxing time, calcination temperature, and scavengers of the reactive species on the degradation activity. It was demonstrated that the ternary magnetic photocatalyst has considerable activity in degradation of two more dye pollutants. Besides, it was demonstrated that the ternary magnetic nanocomposite has reasonable stability during five recycling experiments. - Highlights: • Novel ternary g-C{sub 3}N{sub 4}/Fe{sub 3}O{sub 4}/AgI nanocomposites were prepared using a facile method. • g-C{sub 3}N{sub 4}/Fe{sub 3}O{sub 4}/AgI (20%) has the best activity in degradation of RhB under visible-light. • The activity is 8.7 and 6.9E-fold higher than g-C{sub 3}N{sub 4} and g-C{sub 3}N{sub 4}/Fe{sub 3}O{sub 4}, respectively. • The nanocomposite showed enhance activity in degradation of two more pollutants.

Deviations from Vegard’s law in ternary III-V alloys

KAUST Repository

Murphy, S. T.

2010-08-03

Vegard’s law states that, at a constant temperature, the volume of an alloy can be determined from a linear interpolation of its constituent’s volumes. Deviations from this description occur such that volumes are both greater and smaller than the linear relationship would predict. Here we use special quasirandom structures and density functional theory to investigate such deviations for MxN1−xAs ternary alloys, where M and N are group III species (B, Al, Ga, and In). Our simulations predict a tendency, with the exception of AlxGa1−xAs, for the volume of the ternary alloys to be smaller than that determined from the linear interpolation of the volumes of the MAs and BAs binary alloys. Importantly, we establish a simple relationship linking the relative size of the group III atoms in the alloy and the predicted magnitude of the deviation from Vegard’s law.

Synthesis, morphological control, and antibacterial properties of hollow/solid Ag2S/Ag heterodimers

KAUST Repository

Pang, Maolin

2010-08-11

Ag2S and Ag are important functional materials that have received considerable research interest in recent years. In this work, we develop a solution-based synthetic method to combine these two materials into hollow/solid Ag2S/Ag heterodimers at room temperature. Starting from monodisperse Cu2O solid spheres, CuS hollow spheres can be converted from Cu2O through a modified Kirkendall process, and the obtained CuS can then be used as a solid precursor for preparation of the Ag2S/Ag heterodimers through ion exchange and photo-assisted reduction. We have found that formation of the Ag2S/Ag heterodimers is instantaneous, and the size of Ag nanocrystals on the hollow spheres of Ag2S can be controlled by changing the concentration and power of reducing agents in the synthesis. The growth of Ag nanoparticles on hollow spheres of Ag2S in the dimers is along the [111] direction of the silver crystal; the light absorption properties have also been investigated. Furthermore, coupling or tripling of Ag2S/Ag heterodimers into dumbbell-like trimers ((Ag 2S)2/Ag, linear) and triangular tetramers ((Ag 2S)3/Ag, coplanar) can also be attained at 60°C by adding the bidentate ligand ethylenediamine as a cross-linking agent. To test the applicability of this highly asymmetric dipolar composite, photocatalytic inactivation of Escherichia coli K-12 in the presence of the as-prepared Ag 2S/Ag heterodimers has been carried out under UV irradiation. The added Ag2S/Ag heterodimers show good chemical stability under prolonged UV irradiation, and no appreciable solid dissolution is found. Possible mechanisms regarding the enhanced antibacterial activity have also been addressed. © 2010 American Chemical Society.

A Solution-Doped Polymer Semiconductor:Insulator Blend for Thermoelectrics

KAUST Repository

Kiefer, David; Yu, Liyang; Fransson, Erik; Gó mez, André s; Primetzhofer, Daniel; Amassian, Aram; Campoy-Quiles, Mariano; Mü ller, Christian

2016-01-01

Poly(ethylene oxide) is demonstrated to be a suitable matrix polymer for the solution-doped conjugated polymer poly(3-hexylthiophene). The polarity of the insulator combined with carefully chosen processing conditions permits the fabrication of tens of micrometer-thick films that feature a fine distribution of the F4TCNQ dopant:semiconductor complex. Changes in electrical conductivity from 0.1 to 0.3 S cm−1 and Seebeck coefficient from 100 to 60 μV K−1 upon addition of the insulator correlate with an increase in doping efficiency from 20% to 40% for heavily doped ternary blends. An invariant bulk thermal conductivity of about 0.3 W m−1 K−1 gives rise to a thermoelectric Figure of merit ZT ∼ 10−4 that remains unaltered for an insulator content of more than 60 wt%. Free-standing, mechanically robust tapes illustrate the versatility of the developed dopant:semiconductor:insulator ternary blends.

A Solution-Doped Polymer Semiconductor:Insulator Blend for Thermoelectrics

KAUST Repository

Kiefer, David

2016-09-01

Poly(ethylene oxide) is demonstrated to be a suitable matrix polymer for the solution-doped conjugated polymer poly(3-hexylthiophene). The polarity of the insulator combined with carefully chosen processing conditions permits the fabrication of tens of micrometer-thick films that feature a fine distribution of the F4TCNQ dopant:semiconductor complex. Changes in electrical conductivity from 0.1 to 0.3 S cm−1 and Seebeck coefficient from 100 to 60 μV K−1 upon addition of the insulator correlate with an increase in doping efficiency from 20% to 40% for heavily doped ternary blends. An invariant bulk thermal conductivity of about 0.3 W m−1 K−1 gives rise to a thermoelectric Figure of merit ZT ∼ 10−4 that remains unaltered for an insulator content of more than 60 wt%. Free-standing, mechanically robust tapes illustrate the versatility of the developed dopant:semiconductor:insulator ternary blends.

Chemically deposited In{sub 2}S{sub 3}-Ag{sub 2}S layers to obtain AgInS{sub 2} thin films by thermal annealing

Energy Technology Data Exchange (ETDEWEB)

Lugo, S. [Universidad Autonoma de Nuevo Leon, UANL, Fac. de Ciencias Quimicas, Av. Universidad S/N Ciudad Universitaria San Nicolas de Los Garza Nuevo Leon, C.P. 66451 (Mexico); Pena, Y., E-mail: yolapm@gmail.com [Universidad Autonoma de Nuevo Leon, UANL, Fac. de Ciencias Quimicas, Av. Universidad S/N Ciudad Universitaria San Nicolas de Los Garza Nuevo Leon, C.P. 66451 (Mexico); Calixto-Rodriguez, M. [Centro de Investigacion en Energia-Universidad Nacional Autonoma de Mexico, 62580, Temixco, Morelos (Mexico); Lopez-Mata, C. [Instituto Tecnologico de Chetumal, Av. Insurgentes No. 330, C.P. 77013, Col. David Gustavo Gtz., Chetumal, Quintana Roo (Mexico); Ramon, M.L. [Centro de Investigacion en Energia-Universidad Nacional Autonoma de Mexico, 62580, Temixco, Morelos (Mexico); Gomez, I.; Acosta, A. [Universidad Autonoma de Nuevo Leon, UANL, Fac. de Ciencias Quimicas, Av. Universidad S/N Ciudad Universitaria San Nicolas de Los Garza Nuevo Leon, C.P. 66451 (Mexico)

2012-12-15

Highlights: Black-Right-Pointing-Pointer We obtained polycrystalline silver indium sulfide thin films through the annealing of chemically deposited In{sub 2}S{sub 3}-Ag{sub 2}S films. Black-Right-Pointing-Pointer According to XRD chalcopyrite structure of AgInS{sub 2} was obtained. Black-Right-Pointing-Pointer AgInS{sub 2} thin film has a band gap of 1.86 eV and a conductivity value of 1.2 Multiplication-Sign 10{sup -3} ({Omega} cm){sup -1}. - Abstract: AgInS{sub 2} thin films were obtained by the annealing of chemical bath deposited In{sub 2}S{sub 3}-Ag{sub 2}S layers at 400 Degree-Sign C in N{sub 2} for 1 h. According to the XRD and EDX results the chalcopyrite structure of AgInS{sub 2} has been obtained. These films have an optical band gap, E{sub g}, of 1.86 eV and an electrical conductivity value of 1.2 Multiplication-Sign 10{sup -3} ({Omega} cm){sup -1}.

Transport properties of S0.8Se16M0.2 (M = Al, Ag or Cu) system

International Nuclear Information System (INIS)

Wahab, L.A.

2003-01-01

The results are presented of a study of the electrical and optical properties of vacuum evaporated amorphous thin films in the S 0.8 Se 16 M 0.2 (M=Al, Ag or Cu) system. The activation energy and the pre-exponential factor which appear in the dc conductivity are found to be higher in case of Cu than in case of Ag and Al. The reflectance and transmission are used to measure the optical gap. The glass S 0.8 Se 16 Cu 0.2 behaves as a quasi intrinsic semiconductor (the electrical activation energy is about half of the optical gap). The electrical activation energy is about one-third of the optical gap for the chalcogenide glasses S 0.8 Se 16 Al 0.2 and S 0.8 Se 16 Ag 0.2 . The variation in the refractive index and the imaginary part of the dielectric constant with photon energy have also been reported. The influence of composition on the investigated parameters is reported

Room-temperature ductile inorganic semiconductor

Science.gov (United States)

Shi, Xun; Chen, Hongyi; Hao, Feng; Liu, Ruiheng; Wang, Tuo; Qiu, Pengfei; Burkhardt, Ulrich; Grin, Yuri; Chen, Lidong

2018-05-01

Ductility is common in metals and metal-based alloys, but is rarely observed in inorganic semiconductors and ceramic insulators. In particular, room-temperature ductile inorganic semiconductors were not known until now. Here, we report an inorganic α-Ag2S semiconductor that exhibits extraordinary metal-like ductility with high plastic deformation strains at room temperature. Analysis of the chemical bonding reveals systems of planes with relatively weak atomic interactions in the crystal structure. In combination with irregularly distributed silver-silver and sulfur-silver bonds due to the silver diffusion, they suppress the cleavage of the material, and thus result in unprecedented ductility. This work opens up the possibility of searching for ductile inorganic semiconductors/ceramics for flexible electronic devices.

Special quasirandom structures for binary/ternary group IV random alloys

KAUST Repository

Chroneos, Alexander I.; Jiang, Chao; Grimes, Robin W.; Schwingenschlö gl, Udo

2010-01-01

Simulation of defect interactions in binary/ternary group IV semiconductor alloys at the density functional theory level is difficult due to the random distribution of the constituent atoms. The special quasirandom structures approach is a

In situ controllable synthesis of novel surface plasmon resonance-enhanced Ag{sub 2}WO{sub 4}/Ag/Bi{sub 2}MoO{sub 6} composite for enhanced and stable visible light photocatalyst

Energy Technology Data Exchange (ETDEWEB)

Lv, Jiali [College of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000 (China); Dai, Kai, E-mail: daikai940@chnu.edu.cn [College of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000 (China); Zhang, Jinfeng [College of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000 (China); Lu, Luhua, E-mail: lhlu@cug.edu.cn [Engineering Research Center of Nano-Geomaterials of Ministry of Education, China University of Geosciences, Wuhan 430074 (China); Liang, Changhao, E-mail: chliang@issp.ac.cn [College of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000 (China); Key Laboratory of Materials Physics and Anhui Key Laboratory of Nanomaterials and Nanotechnology, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 23003 (China); Geng, Lei; Wang, Zhongliao; Yuan, Guangyu; Zhu, Guangping [College of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000 (China)

2017-01-01

Highlights: • Novel Ag{sub 2}WO{sub 4}/Ag/Bi{sub 2}MoO{sub 6} ternary photocatalyst was prepared. • Ag{sub 2}WO{sub 4}/Ag/Bi{sub 2}MoO{sub 6} showed enhanced catalytic activity. • Ag{sub 2}WO{sub 4}/Ag/Bi{sub 2}MoO{sub 6} showed long reusable life. - Abstract: A novel hierarchical Ag{sub 2}WO{sub 4}/Ag/Bi{sub 2}MoO{sub 6} ternary visible-light-driven photocatalyst was successfully synthesized by in situ doping Ag{sub 2}WO{sub 4} with Bi{sub 2}MoO{sub 6} nanosheets through a facile hydrothermal and photochemical process. The morphology, structure, optical performance and crystallinity of the products were measured by field emission scanning electron microscope (FESEM), energy dispersive spectrometer (EDS), UV–vis diffuse reflectance spectroscopy (DRS) and X-ray diffraction (XRD). The results showed that Ag{sub 2}WO{sub 4}/Ag was uniformly dispersed on the surface of Bi{sub 2}MoO{sub 6} nanosheets. The photocatalytic performance of Ag{sub 2}WO{sub 4}/Ag/Bi{sub 2}MoO{sub 6} heterostructures was evaluated by the degradation of methylene blue (MB) under 410 nm LED arrays. The ternary Ag{sub 2}WO{sub 4}/Ag/Bi{sub 2}MoO{sub 6} nanocomposite exhibits higher photocatalytic activity than Bi{sub 2}MoO{sub 6} and Ag{sub 2}WO{sub 4}. The synergistic effect of Ag{sub 2}WO{sub 4} and Bi{sub 2}MoO{sub 6} could generated more heterojunctions which promoted photoelectrons transfer from Ag{sub 2}WO{sub 4} to Bi{sub 2}MoO{sub 6}, leading to the improvement of photocatalytic performance by photoelectrons-holes recombination suppression. At the same time, the surface plasmon resonance of Ag{sub 2}WO{sub 4}/Ag/Bi{sub 2}MoO{sub 6} is another crucial reason for the high photocatalytic performance of organic pollutants degradation. And the 20 wt% Ag{sub 2}WO{sub 4}-loaded Bi{sub 2}MoO{sub 6} shows the optimal photocatalytic performance in the degradation of MB. In addition, the ternary composites can be easily reclaimed by precipitation and exhibits high stability of photocatalytic

A simple solution-phase approach to synthesize high quality ternary AgInSe2 and band gap tunable quaternary AgIn(S1-xSe x)2 nanocrystals

KAUST Repository

Bai, Tianyu; Li, Chunguang; Li, Feifei; Zhao, Lan; Wang, Zhaorui; Huang, He; Chen, Cailing; Han, Yu; Shi, Zhan; Feng, Shouhua

2014-01-01

in detail and different reaction conditions all have a great impact on the growth and morphology of the nanocrystals. Alloyed AgIn(S1-xSex)2 nanocrystals with controlled composition across the entire range (0 ≤ x ≤ 1) was also successfully prepared

Trialkylphosphine-stabilized copper(I) gallium(III) phenylchalcogenolate complexes: crystal structures and generation of ternary semiconductors by thermolysis.

Science.gov (United States)

Kluge, Oliver; Krautscheid, Harald

2012-06-18

A series of organometallic trialkylphosphine-stabilized copper gallium phenylchalcogenolate complexes [(R(3)P)(m)Cu(n)Me(2-x)Ga(EPh)(n+x+1)] (R = Me, Et, (i)Pr, (t)Bu; E = S, Se, Te; x = 0, 1) has been prepared and structurally characterized by X-ray diffraction. From their molecular structures three groups of compounds can be distinguished: ionic compounds, ring systems, and cage structures. All these complexes contain one gallium atom bound to one or two methyl groups, whereas the number of copper atoms, and therefore the nuclearity of the complexes, is variable and depends mainly on size and amount of phosphine ligand used in synthesis. The Ga-E bonds are relatively rigid, in contrast to flexible Cu-E bonds. The lengths of the latter are controlled by the coordination number and steric influences. The Ga-E bond lengths depend systematically on the number of methyl groups bound to the gallium atom, with somewhat shorter bonds in monomethyl compounds compared to dimethyl compounds. Quantum chemical computations reproduce this trend and show furthermore that the rotation of one phenyl group around the Ga-E bond is a low energy process with two distinct minima, corresponding to two different conformations found experimentally. Mixtures of different types of chalcogen atoms on molecular scale are possible, and then ligand exchange reactions in solution lead to mixed site occupation. In thermogravimetric studies the complexes were converted into the ternary semiconductors CuGaE(2). The thermolysis reaction is completed at temperatures between 250 and 400 °C, typically with lower temperatures for the heavier chalcogens. Because of significant release of Me(3)Ga during the thermolysis process, and especially in case of copper excess in the precursor complexes, binary copper chalcogenides are obtained as additional thermolysis products. Quaternary semiconductors can be obtained from mixed chalcogen precursors.

Structural and optical properties of AgIn5S8

Science.gov (United States)

Rincón, Carlos A. Durante; Durán, Larissa T.; Medina, Josefa Estévez; Castro, Jaime A.; León, Máximo; Fermín, Jose R.

2017-12-01

Compounds of the chalcogenide family Ag-In-VI (VI = S, Se, Te) are interesting materials due to their stoichiometric stability and potential application in nonlinear optics and solar cells. A polycrystalline ingot of AgIn5S8, an ordered vacancy semiconductor, was prepared by direct fusion of the stoichiometric mixture of the elements in an evacuated quartz ampoule. The presence of a single phase with cubic structure was confirmed by X-ray powder diffraction at room temperature. The lattice parameter, a, was calculated, giving 10.821750 Å. Samples in evacuated quartz ampoules were used to perform Differential Thermal Analysis measurements, showing congruent melting at 1110∘C. Transmittance and reflectivity measurements were used to calculate the absorption coefficient α. From the plot of (αhν)2 versus hν, two direct transitions are observed at 1.25 eV and 1.88 eV. While the higher energy direct transition has been observed by other authors, the direct nature of the lower energy transition was confirmed from the fitting of the plot of the reflectivity versus 1/hν between 0.53 eV-1 (1.89 eV) and 0.55 eV-1 (1.82 eV), obtaining a value of 1.29 eV. The real refractive index n and the high-frequency dielectric constant 𝜀∞ were also obtained from the fit of the reflectivity, resulting to be 2.68 and 7.2, respectively.

Photoconductive properties of organic-inorganic Ag/p-CuPc/n-GaAs/Ag cell

Energy Technology Data Exchange (ETDEWEB)

Karimov, Khasan Sanginovich; Saeed, Muhammad Tariq; Khalid, Fazal Ahmad [GIK Institute of Engineering Sciences and Technology, Top 23640, Swabi, Khyber Pakhtunkhwa (Pakistan); Karieva, Zioda Mirzoevna, E-mail: tariqchani@hotmail.com [Tajik Technical University, Rajabov St.10, Dushanbe, 734000 (Tajikistan)

2011-07-15

A thin film of copper phthalocyanine (CuPc), a p-type semiconductor, was deposited by thermal evaporation in vacuum on an n-type gallium arsenide (GaAs) single-crystal semiconductor substrate. Then semi-transparent Ag thin film was deposited onto the CuPc film also by thermal evaporation to fabricate the Ag/p-CuPc/n-GaAs/Ag cell. Photoconduction of the cell was measured in photoresistive and photodiode modes of operation. It was observed that with an increase in illumination, the photoresistance decreased in reverse bias while it increased in forward bias. The photocurrent was increased in reverse bias operation. In forward bias operation with an increase in illumination, the photocurrent showed a different behavior depending on the voltage applied. (semiconductor physics)

Low-cost spray-processed Ag{sub 1−x}Cu{sub x}InS{sub 2} nano-films: Structural and functional investigation within the Lattice Compatibility Theory framework

Energy Technology Data Exchange (ETDEWEB)

Gherouel, D. [Unité de Physique des Dispositifs à Semi-conducteurs, Faculté des Sciences de Tunis, Tunis El Manar University, 2092 Tunis (Tunisia); Yumak, A. [Physics Department, The Faculty of Arts and Science,Marmara University, 34722 Göztepe, Istanbul (Turkey); Znaidi, M. [Institut Préparatoire Aux Etudes d’Ingénieurs de Nabeul, Merazka, 8000 Nabeul (Tunisia); Bouzidi, A. [Unité de Physique des Dispositifs à Semi-conducteurs, Faculté des Sciences de Tunis, Tunis El Manar University, 2092 Tunis (Tunisia); Boubaker, K., E-mail: mmbb11112000@yahoo.fr [Unité de Physique des Dispositifs à Semi-conducteurs, Faculté des Sciences de Tunis, Tunis El Manar University, 2092 Tunis (Tunisia); Yacoubi, N. [Institut Préparatoire Aux Etudes d’Ingénieurs de Nabeul, Merazka, 8000 Nabeul (Tunisia); Amlouk, M. [Unité de Physique des Dispositifs à Semi-conducteurs, Faculté des Sciences de Tunis, Tunis El Manar University, 2092 Tunis (Tunisia)

2015-08-15

Highlights: • Cu{sub x}Ag{sub 1−x}InS{sub 2} with a minimal lattice mismatch between absorbers and buffers. • The lattice compatibility for understanding silver–copper kinetics. • Controlled and enhanced spray pyrolisis method as a low-cost synthesis protocol. - Abstract: This work deals with some structural and optical investigations about Cu{sub x}Ag{sub 1−x}InS{sub 2} alloys sprayed films and the beneficial effect of copper incorporation in AgInS{sub 2} ternary matrices. The main purpose of this work is to obtain the band gap energy E{sub g} as well as different lattice parameters. The studied properties led to reaching minimum of lattice mismatch between absorber and buffer layers within solar cell devices. As a principal and original finding, the lattice compatibility between both silver and copper indium disulfide structures has been proposed as a guide for understanding kinetics of these materials crystallization.

Improvement of gas-adsorption performances of Ag-functionalized monolayer MoS2 surfaces: A first-principles study

Science.gov (United States)

Song, Jian; Lou, Huan

2018-05-01

Investigations of the adsorptions of representative gases (NO2, NH3, H2S, SO2, CO, and HCHO) on different Ag-functionalized monolayer MoS2 surfaces were performed by first principles methods. The adsorption configurations, adsorption energies, electronic structure properties, and charge transfer were calculated, and the results show that the adsorption activities to gases of monolayer MoS2 are dramatically enhanced by the Ag-modification. The Ag-modified perfect MoS2 (Ag-P) and MoS2 with S-vacancy (Ag-Vs) substrates exhibit a more superior adsorption activity to NO2 than other gases, which is consistent with the experimental reports. The charge transfer processes of different molecules adsorbed on different surfaces exhibit various characteristics, with potential benefits to gas selectivity. For instance, the NO2 and SO2 obtain more electrons from both Ag-P and Ag-Vs substrates but the NH3 and H2S donate more electrons to materials than others. In addition, the CO and HCHO possess totally opposite charge transfer directs on both substrates, respectively. The BS and PDOS calculations show that semiconductor types of gas/Ag-MoS2 systems are more determined by the metal-functionalization of material, and the directs and numbers of charge transfer process between gases and adsorbents can cause the increase or decline of material resistance theoretically, which is helpful to gas detection and distinction. The further analysis indicates suitable co-operation between the gain-lost electron ability of gas and metallicity of featuring metal might adjust the resistivity of complex and contribute to new thought for metal-functionalization. Our works provide new valuable ideas and theoretical foundation for the potential improvement of MoS2-based gas sensor performances, such as sensitivity and selectivity.

Low-temperature solid-state preparation of ternary CdS/g-C{sub 3}N{sub 4}/CuS nanocomposites for enhanced visible-light photocatalytic H{sub 2}-production activity

Energy Technology Data Exchange (ETDEWEB)

Cheng, Feiyue; Yin, Hui; Xiang, Quanjun, E-mail: xiangqj@mail.hzau.edu.cn

2017-01-01

Highlights: • CdS/g-C{sub 3}N{sub 4}/CuS composite were synthesized by low-temperature solid-state method. • CdS/g-C{sub 3}N{sub 4}/CuS show enhanced visible-light photocatalytic H{sub 2} evolution activity. • The enhanced photocatalytic H{sub 2} production activity is due to the heterojunction. • Heterojunction between the components promote charge separation/transfer property. - Abstract: Low-temperature solid-state method were gradually demonstrated as a high efficiency, energy saving and environmental protection strategy to fabricate composite semiconductor materials. CdS-based multiple composite photocatalytic materials have attracted increasing concern owning to the heterostructure constituents with tunable band gaps. In this study, the ternary CdS/g-C{sub 3}N{sub 4}/CuS composite photocatalysts were prepared by a facile and novel low-temperature solid-state strategy. The optimal ternary CdS/g-C{sub 3}N{sub 4}/CuS composite exhibits a high visible-light photocatalytic H{sub 2}-production rate of 57.56 μmol h{sup −1} with the corresponding apparent quantum efficiency reaches 16.5% at 420 nm with Na{sub 2}S/Na{sub 2}SO{sub 3} mixed aqueous solution as sacrificial agent. The ternary CdS/g-C{sub 3}N{sub 4}/CuS composites show the enhanced visible-light photocatalytic H{sub 2}-evolution activity comparing with the binary CdS-based composites or simplex CdS. The enhanced photocatalytic activity is ascribed to the heterojunctions and the synergistic effect of CuS and g-C{sub 3}N{sub 4} in promotion of the charge separation and charge mobility. This work shows that the low-temperature solid-state method is efficient and environmentally benign for the preparation of CdS-based multiple composite photocatalytic materials with enhanced visible-light photocatalytic H{sub 2}-production activity.

Preparation and application of agar/alginate/collagen ternary blend functional food packaging films.

Science.gov (United States)

Wang, Long-Feng; Rhim, Jong-Whan

2015-09-01

Ternary blend agar/alginate/collagen (A/A/C) hydrogel films with silver nanoparticles (AgNPs) and grapefruit seed extract (GSE) were prepared. Their performance properties, transparency, tensile strength (TS), water vapor permeability (WVP), water contact angle (CA), water swelling ratio (SR), water solubility (WS), and antimicrobial activity were determined. The A/A/C film was highly transparent, and both AgNPs and GSE incorporated blend films (A/A/C(AgNPs) and A/A/C(GSE)) exhibited UV-screening effect, especially, the A/A/C(GSE) film had high UV-screening effect without sacrificing the transmittance. In addition, the A/A/C blend films formed efficient hydrogel film with the water holding capacity of 23.6 times of their weight. Both A/A/C(AgNPs) and A/A/C(GSE) composite films exhibited strong antimicrobial activity against both Gram-positive (Listeria monocytogenes) and Gram-negative (Escherichia coli) food-borne pathogenic bacteria. The test results of fresh potatoes packaging revealed that all the A/A/C ternary blend films prevented forming of condensed water on the packaged film surface, both A/A/C(AgNPs) and A/A/C(GSE) composite films prevented greening of potatoes during storage. The results indicate that the ternary blend hydrogel films incorporated with AgNPs or GSE can be used not only as antifogging packaging films for highly respiring fresh agriculture produce, but also as an active food packaging system utilizing their strong antimicrobial activity. Copyright © 2015 Elsevier B.V. All rights reserved.

Measurement of the energetics of metal film growth on a semiconductor: Ag/ Si(100)-2x1

DEFF Research Database (Denmark)

Starr, D.E.; Ranney, J.T.; Larsen, Jane Hvolbæk

2001-01-01

The first direct calorimetric measurements of the energetics of metal film growth on a semiconductor surface are presented. The heat of adsorption of Ag on Si(100)-(2 x 1) at 300 K decreases from similar to 347 to 246 kJ/mol with coverage in the first monolayer (ML) due to overlap of substrate...... strain from nearby Ag islands. It then rises quickly toward the bulk sublimation enthalpy (285 kJ/mol) as 3D particles grow. A wetting layer grows to 1.0 ML, but is metastable above similar to0.55 ML and dewets when kinetics permit. This may be common when adsorbate islands induce a large strain...

OPTOELECTRONIC PROPERTIES OF CdS – AgInS2 SOLAR CELLS

Directory of Open Access Journals (Sweden)

M. A. Abdullaev

2016-01-01

Full Text Available Aim. To conduct experimental studies of optoelectronic properties of CdS - AgInS2 solar cells.Methods. AgInS2 films for solar cell CdS-AgInS2 were obtained by magnetron sputtering of crystalline targets derived from bulk ingots. Cadmium sulfide layers were deposited on the AgInS2 films by an electrochemical method in cadmium salts solution, thiourea and ammonia. AgInS2 bulk crystals were obtained in two stages: a direct fusion of the primary components (99,999 in a stoichiometric ratio, followed by directional solidification in a vertical furnace; re-synthesis has been performed on a staggered basis by heating the obtained ingots at temperatures close to the melting points of elements in the two-zone horizontal furnace.Findings. The paper presents the results of experimental studies of the electrical properties and photosensitivity of CdS-AgInS2 film heterojunction obtained by the magnetron. We measured the current-voltage characteristics and quantum efficiency of photoconversion at temperatures up to 250-356 K. We also identified the short circuit current of up to 25 mA/cm2 and open circuit voltage of 0.38 V.Conclusions. The study of the properties of solar cells in recent years has an important place. The results presented in the work would contribute to more efficient conversion of solar energy into electricity.

Peculiarities of thermoelectric half-Heusler phase formation in Zr–Co–Sb ternary system

Energy Technology Data Exchange (ETDEWEB)

Romaka, V.V., E-mail: romakav@lp.edu.ua [Department of Applied Material Science and Materials Engineering, Lviv Polytechnic National University, Ustyyanovycha Str. 5, 79013 Lviv (Ukraine); Institut für Physikalische Chemie, Universität Wien, Währingerstr. 42, A-1090 Wien (Austria); Romaka, L. [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine); Rogl, P. [Institut für Physikalische Chemie, Universität Wien, Währingerstr. 42, A-1090 Wien (Austria); Stadnyk, Yu. [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine); Melnychenko, N. [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine); Army Academy named after Hetman Petro Sahaydachnyi, Gvardijska Str. 32, 79012 Lviv (Ukraine); Korzh, R.; Duriagina, Z. [Department of Applied Material Science and Materials Engineering, Lviv Polytechnic National University, Ustyyanovycha Str. 5, 79013 Lviv (Ukraine); Horyn, A. [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya Str. 6, 79005 Lviv (Ukraine)

2014-02-05

Highlights: • Phase relations for the Zr–Co–Sb system at 500 °C. • Homogeneity region for half-Heusler phase. • The distribution of DOS for Zr{sub 1+x}Co{sub 1−x}Sb predicts transition from semiconductor (x = 0) to metallic (x = 0.13) like behavior. • The existence of the solid solution Zr{sub 5}Co{sub x}Sb{sub 3+y} (x = 0.0–1.0, y = 0.0–1.0). -- Abstract: The phase equilibria in the Zr–Co–Sb ternary system were studied at 873 K by means of X-ray and metallographic analyses in the whole concentration range. The interaction between the elements results the formation of four ternary compounds at investigated temperature: ZrCoSb (MgAgAs-type), Zr{sub 6}CoSb{sub 2} (K{sub 2}UF{sub 6}-type), Zr{sub 5}CoSb{sub 3} (Hf{sub 5}CuSn{sub 3}-type) and Zr{sub 5}Co{sub 0.5}Sb{sub 2.5} (W{sub 5}Si{sub 3}-type). The limited composition Zr{sub 5}CoSb{sub 3} of the solid solution based on the Zr{sub 5}Sb{sub 3−4} binaries is considered as compound with Hf{sub 5}CuSn{sub 3} structure type. The influence of the disordering and defects in the crystal structure of ZrCoSb on the physical properties was analyzed. The performed electronic structure calculations are in good agreement with electrical and magnetic studies.

Ag/CdS heterostructural composites: Fabrication, characterizations and photocatalysis

International Nuclear Information System (INIS)

Liu, Yang; Chi, Mei; Dong, Hailiang; Jia, Husheng; Xu, Bingshe; Zhang, Zhuxia

2014-01-01

Highlights: • Novel Ag/CdS core–shell heterostructural composites were fabricated using a two-step chemical method. • A formation mechanism of Ag/CdS heterostructural composites. • The photocatalytic activity of Ag/CdS heterostructural composites was found to be improved. • PL emissions are markedly quenched in the Ag/CdS composites than in CdS nanoparticles. - Abstract: Ag/CdS heterostructural materials were successfully synthesized by ultrasound-assisted polyols and hydrothermal method. Under hydrothermal condition, thiourea adsorbed on Ag nanowires releases S 2− ions, which react with vicinal Cd 2+ ions to form CdS clusters on Ag nanowires. Thereafter, the Ag/CdS composites grow into core–shell structure through CdS aggregation, Ostwald ripening, and preferential growth. The obtained core–shell structures and morphologies were investigated by XRD, SEM, and TEM; the experimental results indicate that the composites are composed of Ag nanowires serving as the core and CdS particles as the shell. The photocatalytic property of Ag/CdS core–shell materials was then investigated in detail. Comparing studies on the degradation of methylene blue were employed by using pure CdS, pure Ag, and Ag/CdS composites, respectively. The results show that the Ag/CdS composites possess higher photocatalytic degradation efficiency. Moreover, the Ag/CdS composites show improved stability, and the photocatalytic activity remains almost unchanged after four recycles. The enhanced photocatalytic effect for Ag/CdS composites is mainly attributed to the photogenerated electron transfer from CdS to Ag nanowire, while photogenerated holes still remain in CdS's valence band. Consequently, the effective separation of photogenerated electrons and holes and the resulting OH radicals improve the photocatalytic efficiency of Ag/CdS composites greatly

Structural elucidation of AgAsS2 glass by the analysis of clusters formed during laser desorption ionisation applying quadrupole ion trap time-of-flight mass spectrometry.

Science.gov (United States)

Mawale, Ravi Madhukar; Alberti, Milan; Zhang, Bo; Fraenkl, Max; Wagner, Tomas; Havel, Josef

2016-03-15

The structure of AgA(s)S2 glass, which has a broad range of applications, is still not well understood and a systematic mass spectrometric analysis of AgA(s)S2 glass is currently not available. Elucidation of the structure should help in the development of this material. The AgA(s)S2 glass was prepared by the melt-quenched technique. Laser desorption ionisation (LDI) using quadrupole ion trap time-of-flight mass spectrometry (QIT-TOFMS) was used to follow the generation of Ag(m)As(n)S(x) clusters. The stoichiometry of the clusters generated was determined via collision-induced dissociation (CID) and modelling of isotopic patterns. The AgA(s)S2 glass was characterised by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy. The LDI of AgA(s)S2 glass leads to the formation of unary (Ag+/− and As(3+)) species, 38 binary (As(n)S(x), Ag(m)S(x)), and 98 ternary (Ag(m)As(n)S(x)) singly charged clusters. The formation of silver-rich nano-grains during AgA(s)S2 glass synthesis has been identified using TEM analysis and also verified by QIT-TOFMS. TOFMS was shown to be a useful technique to study the generation of Ag(m)As(n)S(x )clusters. SEM, TEM and EDX analysis proved that the structure of AgA(s)S2 glass is ‘grain-like’ where grains are either: (1) Silver-rich ‘islands’ (Ag(m,) m up to 39) connected by arsenic and/or sulfur or arsenic sulfide chains or (2) silver sulfide (Ag2S)m (m = 9-20) clusters also similarly inter-connected. This obtained structural information may be useful for the development of ultra-high-density phase-change storage and memory devices using this kind of glass as a base.

Synthesis, morphological control, and antibacterial properties of hollow/solid Ag2S/Ag heterodimers

KAUST Repository

Pang, Maolin; Hu, Jiangyong; Zeng, Huachun

2010-01-01

of this highly asymmetric dipolar composite, photocatalytic inactivation of Escherichia coli K-12 in the presence of the as-prepared Ag 2S/Ag heterodimers has been carried out under UV irradiation. The added Ag2S/Ag heterodimers show good chemical stability under

Insights into highly improved solar-driven photocatalytic oxygen evolution over integrated Ag3PO4/MoS2 heterostructures

Science.gov (United States)

Cui, Xingkai; Yang, Xiaofei; Xian, Xiaozhai; Tian, Lin; Tang, Hua; Liu, Qinqin

2018-04-01

Oxygen evolution has been considered as the rate-determining step in photocatalytic water splitting due to its sluggish four-electron half-reaction rate, the development of oxygen-evolving photocatalysts with well-defined morphologies and superior interfacial contact is highly important for achieving high-performance solar water splitting. Herein, we report the fabrication of Ag3PO4/MoS2 nanocomposites and, for the first time, their use in photocatalytic water splitting into oxygen under LED light illumination. Ag3PO4 nanoparticles were found to be anchored evenly on the surface of MoS2 nanosheets, confirming an efficient hybridization of two semiconductor materials. A maximum oxygen-generating rate of 201.6 mol L-1 g-1 h-1 was determined when 200 mg MoS2 nanosheets were incorporated into Ag3PO4 nanoparticles, which is around 5 times higher than that of bulk Ag3PO4. Obvious enhancements in light-harvesting property, as well as electron-hole separation and charge transportation are revealed by the combination of different characterizations. ESR analysis verified that more active oxygen-containing radicals generate over illuminated Ag3PO4/MoS2 composite photocatalysts rather than irradiated Ag3PO4. The improvement in oxygen evolution performance of Ag3PO4/MoS2 composite photocatalysts is ascribed to wide spectra response in the visible-light region, more efficient charge separation and enhanced oxidation capacity in the valence band (VB). This study provides new insights into the design and development of novel composite photocatalytic materials for solar-to-fuel conversion.

Synthesis and characterization of Ag/AgBrO{sub 3} photocatalyst with high photocatalytic activity

Energy Technology Data Exchange (ETDEWEB)

Song, Limin, E-mail: songlmnk@sohu.com [College of Environment and Chemical Engineering & State Key Laboratory of Hollow-Fiber Membrane Materials and Membrane Processes, Tianjin Polytechnic University, Tianjin, 300387 (China); Li, Tongtong [College of Environment and Chemical Engineering & State Key Laboratory of Hollow-Fiber Membrane Materials and Membrane Processes, Tianjin Polytechnic University, Tianjin, 300387 (China); Zhang, Shujuan [College of Science, Tianjin University of Science & Technology, Tianjin, 300457 (China)

2016-10-01

A new Ag/AgBrO{sub 3} photocatalyst was prepared by mixing aqueous solutions of AgNO{sub 3} and NaBrO{sub 3}. The catalyst’s structure and performance were investigated with X-ray powder diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. The UV–vis absorption spectrum of Ag/AgBrO{sub 3} exhibits a band gap of 3.97 eV. The results show that the Ag/AgBrO{sub 3} semiconductor can be excited by ultraviolet–visible light. The photodegradation of Rhodamine B displayed much higher photocatalytic activity than that of N-doped TiO{sub 2} under the same experimental conditions. Moreover, ·OH and ·O{sub 2}{sup −} generated in the photocatalysis played a key role of the photodegradation of Rhodamine B. - Highlights: • Ag/AgBrO{sub 3} with higher photodegradation ability was synthesized. • ·OH and ·O{sub 2}{sup −} radicals were the main active species in the oxidation of RhB. • The possible reaction mechanism was discussed in details.

Peculiarities of linear thermal expansion of CuInS2 single crystal

International Nuclear Information System (INIS)

Akira, Nagaoka; Kenji, Yoshino; Hideto, Miyake

2010-01-01

Full text : I-III-VI 2 chalcopyrire semiconductors have made rapid progress in recent years. In addition chalcopyrite semiconductors show unique thermal properties. Usually, liner thermal expansion in semiconductors increases with increasing temperature. However, liner thermal expansion of most chalcopyrite semiconductors decreases at low temperature. For example, AgGaSe 2 shows decreasing the liner thermal expansion below 100 K 1 , 2). It is well known that high-quality single crystals of the I-III-VI 2 compounds are difficult to grow because most of the compounds grow through a peritectic reaction or a solid state transition during the cooling process. CuInS 2 single crystal can be grown by traveling heater method (THM), which is one of the solution growth techniques. Advantages of the THM growth are following that growth temperature is low compared with that of the other melt growth and larger crystals can be grown compared with a conventional solution growth. In a previous study, CuGaS 2 , CuGaSe 2 , CuGaTe 2 , CuInSe 2 ternary compounds have been obtained by the THM technique. In this work, it is investigated a liner thermal expansion of single crystal CuInS 2 by using X-ray diffraction. Measurement temperature was changed from 10 K to 300 K. From results of XRD measurement, it is calculated lattice constants of a and c axes and the liner thermal expansion. As a result, lattice constants of a axis increase with increasing temperature, that of c axis decreases with increasing temperature. The liner thermal expansion decreases for T 2 single crystal at low temperature

Controlling the emission wavelength in group III-V semiconductor laser diodes

KAUST Repository

Ooi, Boon S.

2016-12-29

Methods are provided for modifying the emission wavelength of a semiconductor quantum well laser diode, e.g. by blue shifting the emission wavelength. The methods can be applied to a variety of semiconductor quantum well laser diodes, e.g. group III-V semiconductor quantum wells. The group III-V semiconductor can include AlSb, AlAs, Aln, AlP, BN, GaSb, GaAs, GaN, GaP, InSb, InAs, InN, and InP, and group III-V ternary semiconductors alloys such as AlxGai.xAs. The methods can results in a blue shifting of about 20 meV to 350 meV, which can be used for example to make group III-V semiconductor quantum well laser diodes with an emission that is orange or yellow. Methods of making semiconductor quantum well laser diodes and semiconductor quantum well laser diodes made therefrom are also provided.

Temperature-agile and structure-tunable optical properties of VO2/Ag thin films

International Nuclear Information System (INIS)

Zhang, X.R.; Hu, X.; Wang, W.; Zhao, Y.; Reinhardt, K.; Knize, R.J.; Lu, Yalin

2012-01-01

By integrating together VO 2 's unique near-room-temperature (RT) semiconductor-metal (S-M) phase transition with a thin silver (Ag) layer's plasmonic properties, VO 2 /Ag multilayers could present a much enhanced optical transmission change when increasing the temperature from RT to over VO 2 's S-M phase-transition temperature. Changing VO 2 and Ag layer thicknesses can also significantly tune their transmission and absorption properties, which could lead to a few useful designs in optoelectronic and energy-saving industries. (orig.)

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

-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. Electronic supplementary information (ESI) available: Fig. S1-S8 and Table S1. See DOI: 10.1039/c3nr03601d

Insight on a novel layered semiconductors: CuTlS and CuTlSe

Energy Technology Data Exchange (ETDEWEB)

Aliev, Ziya S., E-mail: ziyasaliev@gmail.com [Institute of Catalysis and Inorganic Chemistry, ANAS, H.Javid ave. 113, AZ1143 Baku (Azerbaijan); Institute of Physics, ANAS, H.Javid ave. 131, AZ1143 Baku (Azerbaijan); Donostia International Physics Center (DIPC), 20080 San Sebastian (Spain); Zúñiga, Fco. Javier [Departamento de Física de la Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apdo. 644, 48080 Bilbao (Spain); Koroteev, Yury M. [Institute of Strength Physics and Materials Science, Russian Academy of Sciences, Siberian Branch, 634055 Tomsk (Russian Federation); Tomsk State University, Tomsk, 634050 (Russian Federation); Breczewski, Tomasz [Departamento de Física de la Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apdo. 644, 48080 Bilbao (Spain); Babanly, Nizamaddin B. [Institute of Catalysis and Inorganic Chemistry, ANAS, H.Javid ave. 113, AZ1143 Baku (Azerbaijan); Amiraslanov, Imamaddin R. [Institute of Physics, ANAS, H.Javid ave. 131, AZ1143 Baku (Azerbaijan); Politano, Antonio [Department of Physics, University of Calabria, 87036 Rende (CS) (Italy); Madariaga, Gotzon [Departamento de Física de la Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apdo. 644, 48080 Bilbao (Spain); Babanly, Mahammad B. [Institute of Catalysis and Inorganic Chemistry, ANAS, H.Javid ave. 113, AZ1143 Baku (Azerbaijan); and others

2016-10-15

Single crystals of the ternary copper compounds CuTlS and CuTlSe have been successfully grown from stoichiometric melt by using vertical Bridgman-Stockbarger method. The crystal structure of the both compounds has been determined by powder and single crystal X-Ray diffraction. They crystallize in the PbFCl structure type with two formula units in the tetragonal system, space group P4/nmm, a=3.922(2); c=8.123(6); Z=2 and a=4.087(6); c=8.195(19) Å; Z=2, respectively. The band structure of the reported compounds has been analyzed by means of full-potential linearized augmented plane-wave (FLAPW) method based on the density functional theory (DFT). Both compounds have similar band structures and are narrow-gap semiconductors with indirect band gap. The resistivity measurements agree with a semiconductor behavior although anomalies are observed at low temperature. - Graphical abstract: The crystal structures of CuTl and CuTlSe are isostructural with the PbFCl-type and the superconductor LiFeAs-type tetragonal structure. The band structure calculations confirmed that they are narrow-gap semiconductors with indirect band gaps of 0.326 and 0.083 eV. The resistivity measurements, although confirming the semiconducting behavior of both compounds exhibit unusual anomalies at low temperatures. - Highlights: • Single crystals of CuTlS and CuTlSe have been successfully grown by Bridgman-Stockbarger method. • The crystal structure of the both compounds has been determined by single crystal XRD. • The band structure of the both compounds has been analyzed based on the density functional theory (DFT). • The resistivity measurements have been carried out from room temperature down to 10 K.

Stability enhancement of Cu2S against Cu vacancy formation by Ag alloying

Science.gov (United States)

Barman, Sajib K.; Huda, Muhammad N.

2018-04-01

As a potential solar absorber material, Cu2S has proved its importance in the field of renewable energy. However, almost all the known minerals of Cu2S suffer from spontaneous Cu vacancy formation in the structure. The Cu vacancy formation causes the structure to possess very high p-type doping that leads the material to behave as a degenerate semiconductor. This vacancy formation tendency is a major obstacle for this material in this regard. A relatively new predicted phase of Cu2S which has an acanthite-like structure was found to be preferable than the well-known low chalcocite Cu2S. However, the Cu-vacancy formation tendency in this phase remained similar. We have found that alloying silver with this structure can help to reduce Cu vacancy formation tendency without altering its electronic property. The band gap of silver alloyed structure is higher than pristine acanthite Cu2S. In addition, Cu diffusion in the structure can be reduced with Ag doped in Cu sites. In this study, a systematic approach is presented within the density functional theory framework to study Cu vacancy formation tendency and diffusion in silver alloyed acanthite Cu2S, and proposed a possible route to stabilize Cu2S against Cu vacancy formations by alloying it with Ag.

Ternary System with Controlled Structure: A New Strategy toward Efficient Organic Photovoltaics.

Science.gov (United States)

Cheng, Pei; Wang, Rui; Zhu, Jingshuai; Huang, Wenchao; Chang, Sheng-Yung; Meng, Lei; Sun, Pengyu; Cheng, Hao-Wen; Qin, Meng; Zhu, Chenhui; Zhan, Xiaowei; Yang, Yang

2018-02-01

Recently, a new type of active layer with a ternary system has been developed to further enhance the performance of binary system organic photovoltaics (OPV). In the ternary OPV, almost all active layers are formed by simple ternary blend in solution, which eventually leads to the disordered bulk heterojunction (BHJ) structure after a spin-coating process. There are two main restrictions in this disordered BHJ structure to obtain higher performance OPV. One is the isolated second donor or acceptor domains. The other is the invalid metal-semiconductor contact. Herein, the concept and design of donor/acceptor/acceptor ternary OPV with more controlled structure (C-ternary) is reported. The C-ternary OPV is fabricated by a sequential solution process, in which the second acceptor and donor/acceptor binary blend are sequentially spin-coated. After the device optimization, the power conversion efficiencies (PCEs) of all OPV with C-ternary are enhanced by 14-21% relative to those with the simple ternary blend; the best PCEs are 10.7 and 11.0% for fullerene-based and fullerene-free solar cells, respectively. Moreover, the averaged PCE value of 10.4% for fullerene-free solar cell measured in this study is in great agreement with the certified one of 10.32% obtained from Newport Corporation. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Plasmonic Ag{sub 2}MoO{sub 4}/AgBr/Ag composite: Excellent photocatalytic performance and possible photocatalytic mechanism

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhongliao [College of Physics and Electronic Information, Anhui Key Laboratory of Energetic Materials, Huaibei Normal University, Huaibei, 235000 (China); Zhang, Jinfeng, E-mail: zjf_y2004@126.com [College of Physics and Electronic Information, Anhui Key Laboratory of Energetic Materials, Huaibei Normal University, Huaibei, 235000 (China); Lv, Jiali [College of Physics and Electronic Information, Anhui Key Laboratory of Energetic Materials, Huaibei Normal University, Huaibei, 235000 (China); Dai, Kai, E-mail: daikai940@chnu.edu.cn [College of Physics and Electronic Information, Anhui Key Laboratory of Energetic Materials, Huaibei Normal University, Huaibei, 235000 (China); Liang, Changhao [College of Physics and Electronic Information, Anhui Key Laboratory of Energetic Materials, Huaibei Normal University, Huaibei, 235000 (China); Key Laboratory of Materials Physics and Anhui Key Laboratory of Nanomaterials and Nanotechnology, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei, 230031 (China)

2017-02-28

Highlights: • Novel Ag{sub 2}MoO{sub 4}/AgBr/Ag photocatalyst was prepared. • Ag{sub 2}MoO{sub 4}/AgBr/Ag showed high photocatalytic activity. • Ag{sub 2}MoO{sub 4}/AgBr/Ag showed long reusable life. - Abstract: Plasmonic Ag{sub 2}MoO{sub 4}/AgBr/Ag composite is fabricated by in-situ ion exchange and reduction methods at room temperature. The samples are characterized by X-ray diffraction (XRD), UV–vis diffuse reflectance (DRS), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscope (SEM) and photoluminescence (PL) measurements. The results show that butterfly-like Ag{sub 2}MoO{sub 4} nanosheets served as the precursor, and Ag{sub 2}MoO{sub 4}/AgBr/Ag is formed in phase transformation with MoO{sub 4}{sup 2−} displaced by Br{sup −}. The ternary Ag{sub 2}MoO{sub 4}/AgBr/Ag composite photocatalysts show greatly enhanced photocatalytic activity in photodegrading methylene blue (MB) under visible light irradiation compared with AgBr and Ag{sub 2}MoO{sub 4}. The pseudo-first-order rate constant k{sub app} of Ag{sub 2}MoO{sub 4}/AgBr/Ag is 0.602 min{sup −1}, which is 11.6 and 18.3 times as high as that of AgBr and Ag{sub 2}MoO{sub 4}, respectively. Meanwhile, the efficiency of degradation still kept 90% after ten times cyclic experiments. Eventually, possible photocatalytic mechanism was proposed.

Stimulation of the photoluminescent properties of CBD-CdS thin films achieved by structural modifications resulting from Ag{sup +} doping

Energy Technology Data Exchange (ETDEWEB)

Flores-Pacheco, A.; Contreras-Rascon, J.I.; Castillo, S.J.; Alvarez-Ramos, M.E. [Posgrado en Nanotecnologia, Departamento de Fisica, Universidad de Sonora, Hermosillo (Mexico); Diaz-Reyes, J. [Centro de Investigacion en Biotecnologia Aplicada, Instituto Politecnico Nacional, Tepetitla, Tlaxcala (Mexico); Angel-Vicente, P.D. [Instituto Mexicano del Petroleo, Direccion de Investigacion y Posgrado, Ciudad de Mexico (Mexico); Enriquez, J.P. [Centro de Investigacion y Desarrollo Tecnologico en Energias Renovables, Universidad de Ciencias y Artes de Chiapas, Tuxtla Gutierrez (Mexico)

2017-08-15

The present study details the changes in photoluminescence properties stimulated by the structural changes in consequence of doping the II-VI nanocomposite thin-film semiconductor cadmium sulfide (CdS) with the IB metallic ion Ag{sup +}. The synthesis of the matrix and doped semiconductors was performed using low-temperature chemical bath deposition (CBD). The doping percentage of the CdS matrix was determined by energy-dispersive X-ray spectroscopy (EDS) with a value around 3%. The crystallographic study shows a cubic (1 1 1) preferential growth plane for the undoped material. Both X-ray and HRTEM characterizations show the presence of a polycrystalline structure for the Ag{sup +}-doped sample. Measurements of particle size from HRTEM micrographs confirm quantum confinement with a reduction of the average particle size from 5.46 to 4.12 nm in the doped sample. The photoluminescence study shows intense downshifted emissions in the green range of the visible spectrum. This could be due to the shallow electron traps formed by crystalline defects in the lattice, which are induced by the metallic ion. This study also shows higher-energy emissions due to the decrease of the particle size below the effective CdS exciton Bohr radius. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Physical properties of glasses in the Ag2GeS3-AgBr system

Science.gov (United States)

Moroz, M. V.; Demchenko, P. Yu.; Prokhorenko, S. V.; Moroz, V. M.

2013-08-01

Glasses have been prepared by quenching melts in the Ag2GeS3-AgBr system in a range of 0-53 mol % AgBr. The concentration dependences of density, microhardness, glass transition temperatures, and crystallization of alloys have been established. The conductivity of glasses has been investigated by the dc probe method in a range of 240-420 K. The models of the drift motion of silver and halogen ions have been proposed.

A facile room temperature route to ternary Cu{sub 7.2}S{sub 2}Se{sub 2} compounds and their photovoltaic properties based on elemental copper

Energy Technology Data Exchange (ETDEWEB)

Cheng, Jiamei [Department of Chemistry, Zhengzhou University, Henan 450001 (China); Key Laboratory of Micro-Nano Materials for Energy Storage and Conversion of Henan Province, Institute of Surface Micro and Nano Materials, Xuchang University, Henan 461000 (China); Jia, Huimin, E-mail: zhengzhi99999@gmail.com [Key Laboratory of Micro-Nano Materials for Energy Storage and Conversion of Henan Province, Institute of Surface Micro and Nano Materials, Xuchang University, Henan 461000 (China); Lei, Yan [Key Laboratory of Micro-Nano Materials for Energy Storage and Conversion of Henan Province, Institute of Surface Micro and Nano Materials, Xuchang University, Henan 461000 (China); Liu, Songzi [Department of Chemistry, Zhengzhou University, Henan 450001 (China); Key Laboratory of Micro-Nano Materials for Energy Storage and Conversion of Henan Province, Institute of Surface Micro and Nano Materials, Xuchang University, Henan 461000 (China); Gao, Yuanhao [Key Laboratory of Micro-Nano Materials for Energy Storage and Conversion of Henan Province, Institute of Surface Micro and Nano Materials, Xuchang University, Henan 461000 (China); Hou, Hongwei [Department of Chemistry, Zhengzhou University, Henan 450001 (China); Zheng, Zhi, E-mail: zzheng@xcu.edu.cn [Key Laboratory of Micro-Nano Materials for Energy Storage and Conversion of Henan Province, Institute of Surface Micro and Nano Materials, Xuchang University, Henan 461000 (China)

2017-06-01

A one-pot synthesis of novel hierarchical flower-like Cu{sub 7.2}S{sub 2}Se{sub 2} nanocrystals was developed based on the direct metal surface elemental reaction (DMSER) method. This new room temperature synthesis is an economic and environmentally friendly soft chemical approach. The prepared Cu{sub 7.2}S{sub 2}Se{sub 2} nanocrystals uniformly cover the surface of the Cu substrates. The mechanism of formation was investigated by observing the materials produced from changing the reaction time, the molar ratio of Na{sub 2}S to elemental selenium, and the volume of solvent. The crystal structure, surface morphologies and light absorption properties were collected by X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV–visible spectroscopy. The results show that the as-prepared ternary nanocrystals are face-centered cubic and have an optical bandgap of 1.58 eV, which is ideal for potential solar cell applications. Transient photovoltage spectroscopy (TPV) was used to evaluate the photovoltaic performance of pure Cu{sub 7.2}S{sub 2}Se{sub 2} nanocrystalline powder as well as in-situ generated Cu{sub 7.2}S{sub 2}Se{sub 2}/ZnO heterojunctions. The current work offers a novel and simple approach for preparing ternary chalcogenide semiconductors for photoelectric and photocatalytic applications. - Highlights: • A one-pot synthesis of novel hierarchical flower-like Cu{sub 7.2}S{sub 2}Se{sub 2} was developed. • This work offers a facile way for prepare ternary chalcogenide at room temperature. • TPV was firstly used to evaluate the photovoltaic performance of Cu{sub 7.2}S{sub 2}Se{sub 2}.

Silver environment and covalent network rearrangement in GeS3–Ag glasses

International Nuclear Information System (INIS)

Rátkai, L; Jóvári, P; Kaban, I; Wágner, T; Kolář, J; Valková, S; Voleská, Iva; Beuneu, B

2013-01-01

The structure of Ag-doped GeS 3 glasses (0, 15, 20, 25 at.% Ag) was investigated by diffraction techniques and extended x-ray absorption fine structure measurements. Structural models were obtained by fitting the experimental datasets simultaneously by the reverse Monte Carlo simulation technique. It is observed that Ge has mostly S neighbours in GeS 3 , but Ge–Ge bonds appear already at 15% Ag content. Sulfur has ∼2 S/Ge neighbours over the whole concentration range, while the S–Ag coordination number increases with increasing Ag content. Ag–Ag pairs can already be found at 15% Ag. The Ag–S mean coordination number changes from 2.17 ± 0.2 to 2.86 ± 0.2 between 15% and 25% Ag content. Unlike the As–S network in AsS 2 –25Ag glass, the Ge–S network is not fragmented upon Ag-doping of GeS 3 glass. (paper)

AgSbSe2 and AgSb(S,Se)2 thin films for photovoltaic applications

International Nuclear Information System (INIS)

Garza, J.G.; Shaji, S.; Rodriguez, A.C.; Das Roy, T.K.; Krishnan, B.

2011-01-01

Silver antimony selenide (AgSbSe 2 ) thin films were prepared by heating sequentially deposited multilayers of antimony sulphide (Sb 2 S 3 ), silver selenide (Ag 2 Se), selenium (Se) and silver (Ag). Sb 2 S 3 thin film was prepared from a chemical bath containing SbCl 3 and Na 2 S 2 O 3 , Ag 2 Se from a solution containing AgNO 3 and Na 2 SeSO 3 and Se thin films from an acidified solution of Na 2 SeSO 3 , at room temperature on glass substrates. Ag thin film was deposited by thermal evaporation. The annealing temperature was 350 deg. C in vacuum (10 -3 Torr) for 1 h. X-ray diffraction analysis showed that the thin films formed were polycrystalline AgSbSe 2 or AgSb(S,Se) 2 depending on selenium content in the precursor films. Morphology and elemental analysis of these films were done using scanning electron microscopy and energy dispersive X-ray spectroscopy. Optical band gap was evaluated from the UV-visible absorption spectra of these films. Electrical characterizations were done using Hall effect and photocurrent measurements. A photovoltaic structure: glass/ITO/CdS/AgSbSe 2 /Al was formed, in which CdS was deposited by chemical bath deposition. J-V characteristics of this structure showed V oc = 435 mV and J sc = 0.08 mA/cm 2 under illumination using a tungsten halogen lamp. Preparation of a photovoltaic structure using AgSbSe 2 as an absorber material by a non-toxic selenization process is achieved.

Ag nanocrystals anchored CeO2/graphene nanocomposite for enhanced supercapacitor applications

International Nuclear Information System (INIS)

Vanitha, M.; Keerthi; Cao, P.; Balasubramanian, N.

2015-01-01

Highlights: • Quasi spherical Ag and CeO 2 nanoparticles were decorated on rGO matrix. • The Ag/CeO 2 /rGO nanocomposite exhibits specific capacitance of 710 F g −1 . • Ag plays an imperative role in improving the electrochemical performance. - Abstract: A novel ternary Ag decorated CeO 2 /reduced graphene oxide (rGO) nanocomposite was synthesized by a facile hydrothermal method with polyvinylpyrrolidone (PVP) as surface directing agent and was designed as an electrode material for supercapacitors application. The structure and morphology of the nanocomposites were analyzed by X-ray diffraction analysis (XRD), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The synergistic effect between the CeO 2 nanoparticles wrapped rGO matrix with Ag nanoparticles gives rise to a nanostructure, empowering the material with enhanced electrochemical performance. The electrochemical characterization was performed using cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopic studies in 3 M KOH aqueous electrolyte. The nanocomposite electrode materials possess a high specific capacitance of 710.42 F g −1 at an applied current density of 0.2 A g −1 , which was nearly two fold higher than CeO 2 /rGO nanocomposite. This work endows a new route for building Ag/CeO 2 /rGO ternary nanocomposite which will have some impact on the exploitation of novel ternary electrode materials for supercapacitor applications

Implementation of ternary Shor’s algorithm based on vibrational states of an ion in anharmonic potential

Science.gov (United States)

Liu, Wei; Chen, Shu-Ming; Zhang, Jian; Wu, Chun-Wang; Wu, Wei; Chen, Ping-Xing

2015-03-01

It is widely believed that Shor’s factoring algorithm provides a driving force to boost the quantum computing research. However, a serious obstacle to its binary implementation is the large number of quantum gates. Non-binary quantum computing is an efficient way to reduce the required number of elemental gates. Here, we propose optimization schemes for Shor’s algorithm implementation and take a ternary version for factorizing 21 as an example. The optimized factorization is achieved by a two-qutrit quantum circuit, which consists of only two single qutrit gates and one ternary controlled-NOT gate. This two-qutrit quantum circuit is then encoded into the nine lower vibrational states of an ion trapped in a weakly anharmonic potential. Optimal control theory (OCT) is employed to derive the manipulation electric field for transferring the encoded states. The ternary Shor’s algorithm can be implemented in one single step. Numerical simulation results show that the accuracy of the state transformations is about 0.9919. Project supported by the National Natural Science Foundation of China (Grant No. 61205108) and the High Performance Computing (HPC) Foundation of National University of Defense Technology, China.

A ternary functional Ag@GO@Au sandwiched hybrid as an ultrasensitive and stable surface enhanced Raman scattering platform

Science.gov (United States)

Zhang, Cong-yun; Hao, Rui; Zhao, Bin; Hao, Yao-wu; Liu, Ya-qing

2017-07-01

The graphene-mediated surface enhanced Raman scattering (SERS) substrates by virtues of plasmonic metal nanostructures and graphene or its derivatives have attracted tremendous interests which are expected to make up the deficiency of traditional plasmonic metal substrates. Herein, we designed and fabricated a novel ternary Ag@GO@Au sandwich hybrid wherein the ultrathin graphene oxide (GO) films were seamlessly wrapped around the hierarchical flower-like Ag particle core and meanwhile provided two-dimensional anchoring scaffold for the coating of Au nanoparticles (NPs). The surface coverage density of loading Au NPs could be readily controlled by tuning the dosage amount of Au particle solutions. These features endowed the sandwiched structures high enrichment capability for analytes such as aromatic molecules and astonishing SERS performance. The Raman signals were enormously enhanced with an ultrasensitive detection limit of rhodamine-6G (R6G) as low as 10-13 M based on the chemical enhancement from GO and multi-dimensional plasmonic coupling between the metal nanoparticles. In addition, the GO interlayer as an isolating shell could effectively prevent the metal-molecule direct interaction and suppress the oxidation of Ag after exposure at ambient condition which enabled the substrates excellent reproducibility with less than 6% signal variations and prolonged life-time. To evaluate the feasibility and the practical application for SERS detection in real-world samples based on GO sandwiched hybrid as SERS-active substrate, three different prohibited colorants with a series of concentrations were measured with a minimum detected concentration down to 10-9 M. Furthermore, the prepared GO sandwiched nanostructures can be used to identify different types of colorants existing in red wine, implying the great potential applications for single-particle SERS sensing of biotechnology and on-site monitoring in food security.

Ag nanocrystals anchored CeO{sub 2}/graphene nanocomposite for enhanced supercapacitor applications

Energy Technology Data Exchange (ETDEWEB)

Vanitha, M.; Keerthi [Department of Chemical Engineering, A.C Tech, Anna University, Chennai 600025 (India); Cao, P. [Department of Chemical and Materials Engineering, The University of Auckland, PB 92019, Auckland 1142 (New Zealand); Balasubramanian, N., E-mail: nbsbala@annauniv.edu [Department of Chemical Engineering, A.C Tech, Anna University, Chennai 600025 (India)

2015-09-25

Highlights: • Quasi spherical Ag and CeO{sub 2} nanoparticles were decorated on rGO matrix. • The Ag/CeO{sub 2}/rGO nanocomposite exhibits specific capacitance of 710 F g{sup −1}. • Ag plays an imperative role in improving the electrochemical performance. - Abstract: A novel ternary Ag decorated CeO{sub 2}/reduced graphene oxide (rGO) nanocomposite was synthesized by a facile hydrothermal method with polyvinylpyrrolidone (PVP) as surface directing agent and was designed as an electrode material for supercapacitors application. The structure and morphology of the nanocomposites were analyzed by X-ray diffraction analysis (XRD), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The synergistic effect between the CeO{sub 2} nanoparticles wrapped rGO matrix with Ag nanoparticles gives rise to a nanostructure, empowering the material with enhanced electrochemical performance. The electrochemical characterization was performed using cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopic studies in 3 M KOH aqueous electrolyte. The nanocomposite electrode materials possess a high specific capacitance of 710.42 F g{sup −1} at an applied current density of 0.2 A g{sup −1}, which was nearly two fold higher than CeO{sub 2}/rGO nanocomposite. This work endows a new route for building Ag/CeO{sub 2}/rGO ternary nanocomposite which will have some impact on the exploitation of novel ternary electrode materials for supercapacitor applications.

Structural and elastic properties of AIBIIIC 2 VI semiconductors

Science.gov (United States)

Kumar, V.; Singh, Bhanu P.

2018-01-01

The plane wave pseudo-potential method within density functional theory has been used to calculate the structural and elastic properties of AIBIIIC 2 VI semiconductors. The electronic band structure, density of states, lattice constants (a and c), internal parameter (u), tetragonal distortion (η), energy gap (Eg), and bond lengths of the A-C (dAC) and B-C (dBC) bonds in AIBIIIC 2 VI semiconductors have been calculated. The values of elastic constants (Cij), bulk modulus (B), shear modulus (G), Young's modulus (Y), Poisson's ratio (υ), Zener anisotropy factor (A), Debye temperature (ϴD) and G/B ratio have also been calculated. The values of all 15 parameters of CuTlS2 and CuTlSe2 compounds, and 8 parameters of 20 compounds of AIBIIIC 2 VI family, except AgInS2 and AgInSe2, have been calculated for the first time. Reasonably good agreement has been obtained between the calculated, reported and available experimental values.

Building Structural Complexity in Semiconductor Nanocrystals through Chemical Transformations

Energy Technology Data Exchange (ETDEWEB)

Sadtler, Bryce F [Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2009-05-01

Methods are presented for synthesizing nanocrystal heterostructures comprised of two semiconductor materials epitaxially attached within individual nanostructures. The chemical transformation of cation exchange, where the cations within the lattice of an ionic nanocrystal are replaced with a different metal ion species, is used to alter the chemical composition at specific regions ofa nanocrystal. Partial cation exchange was performed in cadmium sulfide (CdS) nanorods of well-defined size and shape to examine the spatial organization of materials within the resulting nanocrystal heterostructures. The selectivity for cation exchange to take place at different facets of the nanocrystal plays an important role in determining the resulting morphology of the binary heterostructure. The exchange of copper (I) (Cu⁺) cations in CdS nanorods occurs preferentially at the ends of the nanorods. Theoretical modeling of epitaxial attachments between different facets of CdS and Cu₂S indicate that the selectivity for cation exchange at the ends of the nanorods is a result of the low formation energy of the interfaces produced. During silver (I) (Ag⁺) cation exchange in CdS nanorods, non-selective nucleation of silver sulfide (Ag₂S), followed by partial phase segregation leads to significant changes in the spatial arrangement of CdS and Ag₂S regions at the exchange reaction proceeds through the nanocrystal. A well-ordered striped pattern of alternating CdS and Ag₂S segments is found at intermediate fractions of exchange. The forces mediating this spontaneous process are a combination of Ostwald ripening to reduce the interfacial area along with a strain-induced repulsive interaction between Ag₂S segments. To elucidate why Cu⁺ and Ag⁺ cation exchange with CdS nanorods produce different morphologies, models for epitaxial attachments between various facets of CdS with Cu₂S or

Structural, electronic and optical properties of AgXY{sub 2}(X = Al, Ga, In and Y = S, Se, Te)

Energy Technology Data Exchange (ETDEWEB)

Ullah, Saeed; Din, Haleem Ud [Materials Modeling Lab, Department of Physics, Islamia College University, Peshawar (Pakistan); Murtaza, G., E-mail: murtaza@icp.edu.pk [Materials Modeling Lab, Department of Physics, Islamia College University, Peshawar (Pakistan); Ouahrani, T. [Laboratoire de Physique Théorique, B.P. 119, Université de Tlemcen, Tlemcen 13000 (Algeria); Khenata, R., E-mail: khenata_rabah@yahoo.fr [Laboratoire de Physique Quantique et de Modélisation Mathématique, Université de Mascara, Mascara 29000 (Algeria); Naeemullah [Department of Physics, G.D.C. Darra Adam Khel, F.R. Kohat, KPK (Pakistan); Bin Omran, S. [Department of Physics and Astronomy, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia)

2014-12-25

Highlights: • The compounds are studied by FP-LAPW method within mBJ approximation. • All of the studied materials show isotropic behavior. • All the compounds show direct band gap nature. • Bonding nature is mostly covalent among the studied compounds. • High absorption peaks and reflectivity ensures there utility in optoelectronic devices. - Abstract: The structural, electronic and optical properties of the ternary semiconducting compounds AgXY{sub 2} (X = Al, Ga, In and Y = S, Se, Te) in Heusler and chalcopyrite crystal phases have been investigated using the density functional theory (DFT) based on the full potential linear augmented plane wave (FP-LAPW) method. The calculated lattice constant and band gap values for AgXY{sub 2} in chalcopyrite phase are in good agreement with the available experimental data. Band structure calculations are performed using modified Becke–Johnson (mBJ) method which match closely with experimental data and yield better band gaps rather than those obtained by using generalized gradient approximation (GGA) and Engel–Vosko generalized gradient approximation (EV–GGA). Decrease in band gap is observed by changing cations X and Y from the top to bottom of periodic table. Chemical bonding trends are predicted through charge density plots and quantified by Bader’s analysis. Optical properties reveal that these compounds are suitable candidates for optoelectronic devices in the visible and ultraviolet (UV) regions.

Two-photon Photoemission of Organic Semiconductor Molecules on Ag(111)

Energy Technology Data Exchange (ETDEWEB)

Yang, Aram [Univ. of California, Berkeley, CA (United States)

2008-05-01

Angle- and time-resolved two-photon photoemission (2PPE) was used to study systems of organic semiconductors on Ag(111). The 2PPE studies focused on electronic behavior specific to interfaces and ultrathin films. Electron time dynamics and band dispersions were characterized for ultrathin films of a prototypical n-type planar aromatic hydrocarbon, PTCDA, and representatives from a family of p-type oligothiophenes.In PTCDA, electronic behavior was correlated with film morphology and growth modes. Within a fewmonolayers of the interface, image potential states and a LUMO+1 state were detected. The degree to which the LUMO+1 state exhibited a band mass less than a free electron mass depended on the crystallinity of the layer. Similarly, image potential states were measured to have free electron-like effective masses on ordered surfaces, and the effective masses increased with disorder within the thin film. Electron lifetimes were correlated with film growth modes, such that the lifetimes of electrons excited into systems created by layer-by-layer, amorphous film growth increased by orders of magnitude by only a few monolayers from the surface. Conversely, the decay dynamics of electrons in Stranski-Krastanov systems were limited by interaction with the exposed wetting layer, which limited the barrier to decay back into the metal.Oligothiophenes including monothiophene, quaterthiophene, and sexithiophene were deposited on Ag(111), and their electronic energy levels and effective masses were studied as a function of oligothiophene length. The energy gap between HOMO and LUMO decreased with increasing chain length, but effective mass was found to depend on domains from high- or low-temperature growth conditions rather than chain length. In addition, the geometry of the molecule on the surface, e.g., tilted or planar, substantially affected the electronic structure.

Fabrication of metal/semiconductor nanocomposites by selective laser nano-welding.

Science.gov (United States)

Yu, Huiwu; Li, Xiangyou; Hao, Zhongqi; Xiong, Wei; Guo, Lianbo; Lu, Yongfeng; Yi, Rongxing; Li, Jiaming; Yang, Xinyan; Zeng, Xiaoyan

2017-06-01

A green and simple method to prepare metal/semiconductor nanocomposites by selective laser nano-welding metal and semiconductor nanoparticles was presented, in which the sizes, phases, and morphologies of the components can be maintained. Many types of nanocomposites (such as Ag/TiO 2 , Ag/SnO 2 , Ag/ZnO 2 , Pt/TiO 2 , Pt/SnO 2 , and Pt/ZnO) can be prepared by this method and their corresponding performances were enhanced.

An investigation of the Pd-Ag-Ru-Gd quaternary system phase diagram

International Nuclear Information System (INIS)

Zhang Kanghou; Xu Yun

2005-01-01

On the basis of the Ag-Pd-Gd, Ag-Ru-Gd and Pd-Ru-Gd ternary systems, the partial phase diagram of Pd-Ag-Ru-Gd (Gd 3 Gd and Ag 51 Gd 14 ; five two-phase regions: Pd(Ag) + (Ru), Pd(Ag) + Ag 51 Gd 14 (Ru) + Ag 51 Gd 14 , Pd(Ag) + Pd 3 Gd and (Ru) + Pd 3 Gd; three three-phase regions: Pd(Ag) + Pd 3 Gd + (Ru), Pd(Ag) + Ag 51 Gd 14 + (Ru) and (Ru) + Ag 51 Gd 14 + Pd 3 Gd; one four-phase region Pd(Ag) + (Ru) + Ag 51 Gd 14 + Pd 3 Gd. No new quaternary intermetallic phase has been found

Phase relations in the M2MoO4 - Ag2MoO4 - Hf(MoO4)2 (M=Li, Na) systems

International Nuclear Information System (INIS)

Bazarova, Zh.G.; Bazarov, B.G.; Balsanova, L.V.

2002-01-01

The M 2 MoO 4 - Ag 2 MoO 4 - Hf(MoO 4 ) 2 (M=Li, Na) systems were studied by X-ray diffraction and differential thermal analyses in the subsolidus area (450 - 500 Deg C) for the first time. The formation of the binary compound with the variable composition Li 4-x Hf 1+0.2x (MoO 4 ) 4 (0 ≤ x ≤ 0.6) in the Li 2 MoO 4 - Hf(MoO 4 ) 2 system and the ternary molybdates Li 4 Ag 2 Hf(MoO 4 ) 5 (S 1 ) and Na 2 Ag 2 Hf(MoO 4 ) 4 (S 2 ) was established and the thermal characteristics of the prepared compounds were examined. The new binary molybdate Ag 2 Hf(MoO 4 ) 3 was prepared by the reaction between Ag 2 MoO 4 and Hf(MoO 4 ) 2 [ru

Energy distribution in semiconductors

International Nuclear Information System (INIS)

Ance, C.

1979-01-01

For various semiconductors the dispersive energy Esub(d) defined in the Wemple-Didomenico model is connected with the covalent and ionic energies Esub(h) and C. A continuous curve of ionicity against the ratio of the two energies Esub(A) and Esub(B), connected to Esub(h) and C is reported. Afromowitz's model is applied to the ternary compounds Gasub(1-x)Alsub(x)Sb using optical decomposition. From these results the average energy gap Esub(g) is given by Esub(g) = D 0 M 0 sup((IB))/(epsilon 1 (0)-1) where M 0 sup((IB)) is the interband transition contribution to the optical moment M 0 . (author)

Ternary particle yields in 249Cf(nth,f)

Science.gov (United States)

Tsekhanovich, I.; Büyükmumcu, Z.; Davi, M.; Denschlag, H. O.; Gönnenwein, F.; Boulyga, S. F.

2003-03-01

An experiment measuring ternary particle yields in 249Cf(nth,f) was carried out at the high flux reactor of the Institut Laue-Langevin using the Lohengrin recoil mass separator. Parameters of energy distributions were determined for 27 ternary particles up to 30Mg and their yields were calculated. The yields of 17 further ternary particles were estimated on the basis of the systematics developed. The heaviest particles observed in the experiment are 37Si and 37S; their possible origin is discussed.

Crystal Growth of ZnSe and Related Ternary Compound Semiconductors by Vapor Transport in Low Gravity

Science.gov (United States)

Su, Ching-Hua; Ramachandran, N.

2013-01-01

Crystals of ZnSe and related ternary compounds, such as ZnSeS and ZnSeTe, will be grown by physical vapor transport in the Material Science Research Rack (MSRR) on International Space Station (ISS). The objective of the project is to determine the relative contributions of gravity-driven fluid flows to the compositional distribution, incorporation of impurities and defects, and deviation from stoichiometry observed in the crystals grown by vapor transport as results of buoyance-driven convection and growth interface fluctuations caused by irregular fluid-flows on Earth. The investigation consists of extensive ground-based experimental and theoretical research efforts and concurrent flight experimentation. The objectives of the ground-based studies are (1) obtain the experimental data and conduct the analyses required to define the optimum growth parameters for the flight experiments, (2) perfect various characterization techniques to establish the standard procedure for material characterization, (3) quantitatively establish the characteristics of the crystals grown on Earth as a basis for subsequent comparative evaluations of the crystals grown in a low-gravity environment and (4) develop theoretical and analytical methods required for such evaluations. ZnSe and related ternary compounds have been grown by vapor transport technique with real time in-situ non-invasive monitoring techniques. The grown crystals have been characterized extensively by various techniques to correlate the grown crystal properties with the growth conditions.

Photoinduced formation of Ag nanoparticles on the surface of As2S3/Ag thin bilayer

International Nuclear Information System (INIS)

Binu, S; Khan, Pritam; Barik, A R; Sharma, Rituraj; Adarsh, K V; Golovchak, R; Jain, H

2014-01-01

In this article, we demonstrate the combined effect of photodoping and photoinduced-surface deposition in a bilayer of chalcogenide glass (ChG) and Ag as an alternative method to optically synthesize Ag nanoparticles (AgNP) on the surface of ChG. In our experiment, AgNP formation occurs through two distinct stages: In the first stage, Ag is transported through the As 2 S 3 layer as Ag + ions, and in the second stage Ag + ions are photo-deposited as AgNP. The ex situ x-ray photoelectron spectroscopy measurements and AFM observations show photoinduced Ag mass transport and the formation of AgNP. (paper)

Semiconductor detectors in the low countries

CERN Document Server

Heijne, Erik H M

2003-01-01

Several milestones in the development of semiconductor radiation imaging detectors are attributed to scientists from the Low Countries, the Netherlands and Belgium, and a few historical details will be highlighted. The very first usable semiconductor nuclear detector was made in Utrecht, around 1943, in the form of an AgCl crystal. The earliest large-scale application of monolithic, double- sided silicon strip detectors was in the BOL experiment around 1968 at IKO, now NIKHEF, in Amsterdam. The technology developed and patented by Philips and IKO was adapted by the author and coworkers in 1980 to produce the first silicon microstrip detector used for the reconstruction of events in a CERN fixed target experiment. An avalanche of developments then led to worldwide use of silicon microstrip detectors in elementary particle physics, motivated by the capability to reconstruct particles with lifetime similar to 10**- **1**2s, which decay on sub-millimeter scale. The intensive activity in silicon detector R&D c...

Surface reconstruction of titania with g-C3N4 and Ag for promoting efficient electrons migration and enhanced visible light photocatalysis

International Nuclear Information System (INIS)

Leong, Kah Hon; Liu, Sze Ling; Sim, Lan Ching; Saravanan, Pichiah; Jang, Min; Ibrahim, Shaliza

2015-01-01

Graphical abstract: - Highlights: • Visible light responsive TiO 2 was reconstructed with g-C 3 N 4 and Ag by simple route. • g-C 3 N 4 simultaneously promoted electrons migration and tuned energy gap of TiO 2 . • Ag facilitated electron junction and enhanced the visible light through SPR. • Reconstructed TiO 2 showed an excellent photocatalytic performance by removing AMX. - Abstract: The developments of heterogeneous photocatalysts are one among the competent reconstruction approach to enrich the visible light responsiveness of conventional TiO 2 . In the present work the TiO 2 was reconstructed with graphitic carbon nitride (g-C 3 N 4 ) and silver (Ag) to form a ternary (g-C 3 N 4 )–Ag/TiO 2 . The graphitic carbon nitride an intriguing material was prepared through a facile pyrolysis by using urea as a precursor. The silver (Ag) that plays a role as electron-conduction mobiliser in the ternary was synthesised through solar mediated photodeposition method. The synthesised ternary composite characteristics were thoroughly investigated through various physical and chemical analyses. The presence of g-C 3 N 4 in the ternary photocatalysts promoted the formation of interface between the Ag/TiO 2 and g-C 3 N 4 and stimulated the electron transfer between them. These electrons migration acknowledged by the synergic effect prolonged the lifetime of charge carriers. The g-C 3 N 4 also significantly tuned the energy band of conventional TiO 2 . The prepared ternary exhibited significantly high visible light photocatalytic performance by degrading Amoxicillin (AMX) a poor photosensitising pollutant at highest rate.

Synthesis of Ag{sub 2}S nanorods by biomimetic method in the lysozyme matrix

Energy Technology Data Exchange (ETDEWEB)

Qin, Dezhi, E-mail: dezhiqin@163.com; Zhang, Li; He, Guoxu; Zhang, Qiuxia

2013-09-01

Graphical abstract: - Highlights: • Firstly, Ag{sub 2}S nanorods were synthesized by biomimetic method in the lysozyme solutions. • The study of the interaction between Ag{sup +} and the lysozyme. • Discussion of possible formation mechanism of Ag{sub 2}S nanorods. • The synthesis process of lyso-conjugated Ag{sub 2}S nanocrystals is facile, effective and environment friendly. - Abstract: Ag{sub 2}S nanorods were successfully synthesized by biomimetic route in the lysozyme solution at physiological temperature and atmospheric pressure. The transmission electron microscopy (TEM) images revealed that the prepared nanorods are uniform and monodisperse with homogeneous size about 50 nm in diameter and 150 nm in length. The optical property of Ag{sub 2}S nanocrystals was studied by the ultraviolet–visible (UV–vis) and photoluminescence (PL) spectroscopy, the results show that the products exhibit well-defined emission at 471 nm and 496 nm excited by 292 nm. The interaction of Ag{sup +}/Ag{sub 2}S with the lysozyme was investigated through Fourier transform infrared (FT-IR) spectroscopy, which shows that the cooperation effect of the lysozyme and Ag{sup +} could be responsible for the formation of as obtained Ag{sub 2}S nanorods.

Ag on Si(111) from basic science to application

Energy Technology Data Exchange (ETDEWEB)

Belianinov, Aleksey [Iowa State Univ., Ames, IA (United States)

2012-01-01

In our work we revisit Ag and Au adsorbates on Si(111)-7x7, as well as experiment with a ternary system of Pentacene, Ag and Si(111). Of particular interest to us is the Si(111)-(√3x√3)R30°}–Ag (Ag-Si-√3 hereafter). In this thesis I systematically explore effects of Ag deposition on the Ag-Si-√3 at different temperatures, film thicknesses and deposition fluxes. The generated insight of the Ag system on the Si(111) is then applied to generate novel methods of nanostructuring and nanowire growth. I then extend our expertise to the Au system on the Ag-Si(111) to gain insight into Au-Si eutectic silicide formation. Finally we explore behavior and growth modes of an organic molecule on the Ag-Si interface.

Theoretical optoelectronic analysis of intermediate-band photovoltaic material based on ZnY1−xOx (Y = S, Se, Te) semiconductors by first-principles calculations

International Nuclear Information System (INIS)

Wu Kong-Ping; Zhou Meng-Ran; Huang You-Rui; Gu Shu-Lin; Ye Jian-Dong; Zhu Shun-Ming; Zhang Rong; Zheng You-Dou; Tang Kun

2013-01-01

The structural, energetic, and electronic properties of lattice highly mismatched ZnY 1−x O x (Y = S, Se, Te) ternary alloys with dilute O concentrations are calculated from first principles within the density functional theory. We demonstrate the formation of an isolated intermediate electronic band structure through diluted O-substitute in zinc-blende ZnY (Y = S, Se, Te) at octahedral sites in a semiconductor by the calculations of density of states (DOS), leading to a significant absorption below the band gap of the parent semiconductor and an enhancement of the optical absorption in the whole energy range of the solar spectrum. It is found that the intermediate band states should be described as a result of the coupling between impurity O 2p states with the conduction band states. Moreover, the intermediate bands (IBs) in ZnTeO show high stabilization with the change of O concentration resulting from the largest electronegativity difference between O and Te compared with in the other ZnSO and ZnSeO. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Ternary particle yields in 249Cf(nth,f)

International Nuclear Information System (INIS)

Tsekhanovich, I.; Bueyuekmumcu, Z.; Davi, M.; Denschlag, H.O.; Goennenwein, F.; Boulyga, S.F.

2003-01-01

An experiment measuring ternary particle yields in 249 Cf(n th ,f) was carried out at the high flux reactor of the Institut Laue-Langevin using the Lohengrin recoil mass separator. Parameters of energy distributions were determined for 27 ternary particles up to 30 Mg and their yields were calculated. The yields of 17 further ternary particles were estimated on the basis of the systematics developed. The heaviest particles observed in the experiment are 37 Si and 37 S; their possible origin is discussed

Ternary CoS{sub 2}/MoS{sub 2}/RGO electrocatalyst with CoMoS phase for efficient hydrogen evolution

Energy Technology Data Exchange (ETDEWEB)

Liu, Yan-Ru; Shang, Xiao [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China); Gao, Wen-Kun [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China); College of Science, China University of Petroleum (East China), Qingdao 266580 (China); Dong, Bin, E-mail: dongbin@upc.edu.cn [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China); College of Science, China University of Petroleum (East China), Qingdao 266580 (China); Chi, Jing-Qi; Li, Xiao; Yan, Kai-Li; Chai, Yong-Ming [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China); Liu, Yun-Qi, E-mail: liuyq@upc.edu.cn [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China); Liu, Chen-Guang [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China)

2017-08-01

Highlights: • Ternary CoS{sub 2}/MoS{sub 2}/RGO with CoMoS phase as electrocatalyst for HER was prepared. • CoMoS phase have the metallic nature and highly intrinsic activity for HER. • RGO support ensures good distribution of CoMoS phase and enhances the conductivity. • The introduction of CoMoS and RGO may be a novel strategy for efficient HER of MoS{sub 2}. - Abstract: CoMoS phase with metallic character plays crucial role on enhancing the activity of MoS{sub 2} electrocatalysts for hydrogen evolution reaction (HER). However, only Co atoms located in the edges of MoS{sub 2} can create CoMoS phase, so it is a challenge to obtain CoMoS phase with homogeneous distribution limited by the layered MoS{sub 2} and doping method of Co. Herein, we reported a simple one-pot hydrothermal method to prepare novel ternary CoS{sub 2}/MoS{sub 2}/RGO with CoMoS phase for HER using reduced graphene oxide (RGO) as support. XPS proves the formation of CoMoS phase, implying the enhanced activity for HER. RGO support ensures the well distribution of CoMoS phase and enhances the conductivity of CoS{sub 2}/MoS{sub 2}/RGO. Compared to CoS{sub 2}/RGO, MoS{sub 2}/RGO and CoS{sub 2}/MoS{sub 2}, the obtained CoS{sub 2}/MoS{sub 2}/RGO shows superior activity for HER with an onset overpotential of −80 mV (vs. RHE), small Tafel slope of 56 mV dec{sup −1}, high exchange current density of 11.4 μA cm{sup −2} and rigid electrochemical durability. The enhanced performances for HER may be ascribed to the formation of CoMoS phase with high activity and the existence of RGO support with good electrical conductivitys in ternary CoS{sub 2}/MoS{sub 2}/RGO. Therefore, the introduction of CoMoS phase and RGO into MoS{sub 2} could effectively enhance electrocatalytic properties for HER.

Photocatalytic degradation of H2S aqueous media using sulfide nanostructured solid-solution solar-energy-materials to produce hydrogen fuel.

Science.gov (United States)

Lashgari, Mohsen; Ghanimati, Majid

2018-03-05

H 2 S is a corrosive, flammable and noxious gas, which can be neutralized by dissolving in alkaline media and employed as H 2 -source by utilizing inside semiconductor-assisted/photochemical reactors. Herein, through a facile hydrothermal route, a ternary nanostructured solid-solution of iron, zinc and sulfur was synthesized in the absence and presence of Ag-dopant, and applied as efficient photocatalyst of hydrogen fuel production from H 2 S media. The effect of pH on the photocatalyst performance was scrutinized and the maximum activity was attained at pH=11, where HS - concentration is high. BET, diffuse reflectance and photoluminescence studies indicated that the ternary solid-solution photocatalyst, in comparison to its solid-solvent (ZnS), has a greater surface area, stronger photon absorption and less charge recombination, which justify its superiority. Moreover, the effect of silver-dopant on the photocatalyst performance was examined. The investigations revealed that although silver could boost the absorption of photons and increase the surface area, it could not appreciably enhance the photocatalyst performance due to its weak influence on retarding the charge-recombination process. Finally, the phenomenon was discussed in detail from mechanistic viewpoint. Copyright © 2017 Elsevier B.V. All rights reserved.

Phase relations in the quasi-binary Cu{sub 2}GeS{sub 3}-ZnS and quasi-ternary Cu{sub 2}S-Zn(Cd)S-GeS{sub 2} systems and crystal structure of Cu{sub 2}ZnGeS{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Parasyuk, O.V. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine)]. E-mail: oleg@lab.univer.lutsk.ua; Piskach, L.V. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine); Romanyuk, Y.E. [Advanced Photonics Laboratory, Institute of Imaging and Applied Optics, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Olekseyuk, I.D. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine); Zaremba, V.I. [Department of Inorganic Chemistry, Ivan Franko National University of Lviv, 6 Kyryla and Mefodiya Str., 79005 L' viv (Ukraine); Pekhnyo, V.I. [V.I. Vernadskii Institute of General and Inorganic Chemistry, Ukrainian National Academy of Sciences, Palladina Ave 32-34, 03680 Kiev (Ukraine)

2005-07-19

The isothermal section of the Cu{sub 2}S-Zn(Cd)S-GeS{sub 2} systems at 670K was constructed using X-ray diffraction analysis. At this temperature, two quaternary intermediate phases, Cu{sub 2}CdGeS{sub 4} and {approx}Cu{sub 8}CdGeS{sub 7}, exist in the Cu{sub 2}S-CdS-GeS{sub 2} system, and only one phase, Cu{sub 2}ZnGeS{sub 4}, exists in the Cu{sub 2}S-ZnS-GeS{sub 2} system. The phase diagram of the Cu{sub 2}GeS{sub 3}-ZnS system was constructed using differential-thermal analysis and X-ray diffraction, and the existence of Cu{sub 2}ZnGeS{sub 4} has been confirmed. It forms incongruently at 1359K. Powder X-ray diffraction was used to refine the crystal structure of Cu{sub 2}ZnGeS{sub 4}, which crystallizes in the tetragonal stannite-type structure at 670K (space group I4-bar 2m, a=0.534127(9)nm, c=1.05090(2)nm, R{sub I}=0.0477). The possibility of the formation of quaternary compounds in the quasi-ternary systems A{sup I}{sub 2}X-B{sup II}X-C{sup IV}X{sub 2}, where A{sup I}-Cu, Ag; B{sup II}-Zn, Cd, Hg; C{sup IV}-Si, Ge, Sn and X-S, Se, Te is discussed.

NiS and MoS2 nanosheet co-modified graphitic C3N4 ternary heterostructure for high efficient visible light photodegradation of antibiotic.

Science.gov (United States)

Lu, Xuejun; Wang, Yu; Zhang, Xinyi; Xu, Guangqing; Wang, Dongmei; Lv, Jun; Zheng, Zhixiang; Wu, Yucheng

2018-01-05

The development of efficient solar driven catalytic system for the degradation of antibiotics has become increasingly important in environmental protection and remediation. Non-noble-metal NiS and MoS 2 nanosheet co-modified graphitic C 3 N 4 ternary heterostructure has been synthesized via a facile combination of hydrothermal and ultrasound method, and the ternary heterostructure has been utilized for photocatalytic degradation of antibiotic agents. The antibiotics of ciprofloxacin (CIP) and tetracycline hydrochloride (TC) were photodegraded by the hybrid under the visible light. The optimal photodegradation rate of the ternary heterostructure reaches about 96% after 2h irradiation, which is 2.1 times higher than that of pure g-C 3 N 4 for TC degradation. The photocatalytic degradation rates of the ternary heterostructure for both CIP and TC obey the pseudo-first-order kinetic model. The enhanced visible light adsorption and charge separation efficiency contribute to the photocatalytic performance of the ternary heterostructure. This work provides new insights and pathways by which efficient degradation of antibiotics can be achieved and will stimulate further studies in this important field. Copyright © 2017 Elsevier B.V. All rights reserved.

Magnetization study of interlayer exchange in semiconductor EuS-PbS ferromagnetic wedge multilayers

International Nuclear Information System (INIS)

Kowalczyk, L.; Osinniy, V.; Chernyshova, M.; Dziawa, P.; Boratynski, A.; Story, T.; Smits, C.J.P.; Swagten, H.J.M.; Sipatov, A.Yu.; Volobuev, V.V.

2006-01-01

Interlayer coupling was experimentally studied in semiconductor EuS-PbS ferromagnetic superlattice wedge structures grown on KCl (0 0 1) substrates with the wedges covering the semiconductor nonmagnetic PbS spacer layer thickness from 0.3 to 6 nm. Structural parameters of the wedges were examined by X-ray diffraction analysis of EuS-PbS superlattice period. Measurements of magnetic hysteresis loops of EuS-PbS structures were performed by both SQUID (for small terminal parts of the wedge) and MOKE (magneto-optical analysis along the wedge) magnetometry. A strong decrease of magnetic remanence and an increase of saturation field observed for EuS-PbS structures with the PbS spacer thickness decreasing below about 1.5 nm is discussed in terms of the influence of antiferromagnetic interlayer coupling

AgSbSe{sub 2} and AgSb(S,Se){sub 2} thin films for photovoltaic applications

Energy Technology Data Exchange (ETDEWEB)

Garza, J.G. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Shaji, S. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Facultad de Ingenieria Mecanica y Electrica, CIIDIT - Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico); Rodriguez, A.C.; Das Roy, T.K. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Krishnan, B., E-mail: kbindu_k@yahoo.com [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Facultad de Ingenieria Mecanica y Electrica, CIIDIT - Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico)

2011-10-01

Silver antimony selenide (AgSbSe{sub 2}) thin films were prepared by heating sequentially deposited multilayers of antimony sulphide (Sb{sub 2}S{sub 3}), silver selenide (Ag{sub 2}Se), selenium (Se) and silver (Ag). Sb{sub 2}S{sub 3} thin film was prepared from a chemical bath containing SbCl{sub 3} and Na{sub 2}S{sub 2}O{sub 3}, Ag{sub 2}Se from a solution containing AgNO{sub 3} and Na{sub 2}SeSO{sub 3} and Se thin films from an acidified solution of Na{sub 2}SeSO{sub 3}, at room temperature on glass substrates. Ag thin film was deposited by thermal evaporation. The annealing temperature was 350 deg. C in vacuum (10{sup -3} Torr) for 1 h. X-ray diffraction analysis showed that the thin films formed were polycrystalline AgSbSe{sub 2} or AgSb(S,Se){sub 2} depending on selenium content in the precursor films. Morphology and elemental analysis of these films were done using scanning electron microscopy and energy dispersive X-ray spectroscopy. Optical band gap was evaluated from the UV-visible absorption spectra of these films. Electrical characterizations were done using Hall effect and photocurrent measurements. A photovoltaic structure: glass/ITO/CdS/AgSbSe{sub 2}/Al was formed, in which CdS was deposited by chemical bath deposition. J-V characteristics of this structure showed V{sub oc} = 435 mV and J{sub sc} = 0.08 mA/cm{sup 2} under illumination using a tungsten halogen lamp. Preparation of a photovoltaic structure using AgSbSe{sub 2} as an absorber material by a non-toxic selenization process is achieved.

CsAg{sub 5}Te{sub 3}: a new metal-rich telluride with a unique tunnel structure

Energy Technology Data Exchange (ETDEWEB)

Jing, Li [Rutgers Univ., Camden, NJ (United States). Dept. of Chem.; Hongyou, Guo [Rutgers Univ., Camden, NJ (United States). Dept. of Chem.; Xiang, Zhang [Michigan State Univ., East Lansing, MI (United States). Dept. of Chemistry; Kanatzidis, M G [Michigan State Univ., East Lansing, MI (United States). Dept. of Chemistry

1995-02-15

The synthesis and structure of a new ternary silver telluride, CsAg{sub 5}Te{sub 3}, is described. The compound was prepared from a Cs{sub 2}Te-CaTe-Te flux but it can also be prepared from a direct combination of Cs{sub 2}Te and Ag{sub 2}Te under vacuum at 600 C. The crystal data for CsAg{sub 5}Te{sub 3} at 20 C (Mo K{alpha} radiation) are as follows: a=14.672(2) A and c=4.601(3) A; V=990.5(8) A{sup 3}; Z=4; D{sub calc}=7.075 g cm{sup -3}; space group, P4{sub 2} /mnm (No. 136); 2{theta}{sub max}=50 ; number of independent data collected, 572; number of data observed with I>3{sigma}(I), 267; number of variables, 32; {mu}=218.51 cm{sup -1}; extinction coefficient, 0.585x10{sup -7}; final R=0.040; R{sub w}=0.046; goodness of fit, 1.42. The compound features a new structure type with Cs{sup +}-filled, relatively large tunnels running through the lattice. The material is a semiconductor with a band gap of about 0.65 eV. ((orig.))

Evaluation of a New Biosensor Based on in Situ Synthesized PPy-Ag-PVP Nanohybrid for Selective Detection of Dopamine.

Science.gov (United States)

Vellaichamy, Balakumar; Periakaruppan, Prakash; Paulmony, Tharmaraj

2017-02-09

In the present work, in situ synthesis of polypyrrole-silver-polyvinylpyrrolidone (PPy-Ag-PVP) nanohybrid using AgNO 3 as an oxidant and polyvinylpyrrolidone (PVP) as a stabilizer and surfactant is demonstrated. The obtained ternary PPy-Ag-PVP nanohybrid was characterized by UV-vis, FT-IR, XRD, Raman, TGA, SEM, and HR-TEM analysis. Further the synthesized PPy-Ag-PVP has been investigated for its selective and sensitive sensing of dopamine (DA). The PPy-Ag-PVP modified glassy carbon electrode shows a reversible electrochemical behavior with superior response for DA. The limit of detection and limit of quantification are found to be 0.0126 and 0.042 μM (S/N = 3 and 10), respectively, with remarkable sensitivity (7.26 μA mM -1 cm -2 ). The practical application of the present modified electrode has been validated by determining the concentration of DA in human urine samples of different age group.

High thermally stable Ni /Ag(Al) alloy contacts on p-GaN

Science.gov (United States)

Chou, C. H.; Lin, C. L.; Chuang, Y. C.; Bor, H. Y.; Liu, C. Y.

2007-01-01

Ag agglomeration was found to occur at Ni /Ag to p-GaN contacts after annealing at 500°C. This Ag agglomeration led to the poor thermal stability showed by the Ni /Ag contacts in relation to the reflectivity and electrical properties. However, after alloying with 10at.% Al by e-gun deposition, the Ni /Ag(Al) p-GaN contacts were found to effectively retard Ag agglomeration thereby greatly enhancing the thermal stability. Based on the x-ray photoelectron spectroscopy analysis, the authors believe that the key for the retardation of Ag agglomeration was the formation of ternary Al-Ni-O layer at p-GaN interface.

Design of Ag-Ge-Zn braze/solder alloys: Experimental thermodynamics and surface properties

Directory of Open Access Journals (Sweden)

Delsante S.

2017-01-01

Full Text Available The experimental investigation of the Ag-Ge-Zn phase diagram was performed by using combined microstructural and Differential Scanning Calorimeter (DSC analyses. The samples were subjected to thermal cycles by a heat-flux DSC apparatus with heating and cooling rate of 0.5 or 0.3°C/min. The microstructure of the samples, both after annealing and after DSC analysis, was studied by optical and scanning electron microscopy coupled with EDS (Energy Dispersive Spectroscopy analysis. Considering the slow heating and cooling rate adopted, the isothermal section at room temperature was established. No ternary compounds were observed. On the basis of the experimental investigations the invariant reactions were identified. Combining the thermodynamic data on the Ag-Ge, Ag-Zn and Ge-Zn liquid phases by means of Butler’s model the surface tension of Ag-Ge-Zn alloys was calculated.

Ternary oxide nanostructures and methods of making same

Science.gov (United States)

Wong, Stanislaus S [Stony Brook, NY; Park, Tae-Jin [Port Jefferson, NY

2009-09-08

A single crystalline ternary nanostructure having the formula A.sub.xB.sub.yO.sub.z, wherein x ranges from 0.25 to 24, and y ranges from 1.5 to 40, and wherein A and B are independently selected from the group consisting of Ag, Al, As, Au, B, Ba, Br, Ca, Cd, Ce, Cl, Cm, Co, Cr, Cs, Cu, Dy, Er, Eu, F, Fe, Ga, Gd, Ge, Hf, Ho, I, In, Ir, K, La, Li, Lu, Mg, Mn, Mo, Na, Nb, Nd, Ni, Os, P, Pb, Pd, Pr, Pt, Rb, Re, Rh, Ru, S, Sb, Sc, Se, Si, Sm, Sn, Sr, Ta, Tb, Tc, Te, Ti, Tl, Tm, U, V, W, Y, Yb, and Zn, wherein the nanostructure is at least 95% free of defects and/or dislocations.

Growth of Wide Band Gap II-VI Compound Semiconductors by Physical Vapor Transport

Science.gov (United States)

Su, Ching-Hua; Sha, Yi-Gao

1995-01-01

The studies on the crystal growth and characterization of II-VI wide band gap compound semiconductors, such as ZnTe, CdS, ZnSe and ZnS, have been conducted over the past three decades. The research was not quite as extensive as that on Si, III-V, or even narrow band gap II-VI semiconductors because of the high melting temperatures as well as the specialized applications associated with these wide band gap semiconductors. In the past several years, major advances in the thin film technology such as Molecular Beam Epitaxy (MBE) and Metal Organic Chemical Vapor Deposition (MOCVD) have demonstrated the applications of these materials for the important devices such as light-emitting diode, laser and ultraviolet detectors and the tunability of energy band gap by employing ternary or even quaternary systems of these compounds. At the same time, the development in the crystal growth of bulk materials has not advanced far enough to provide low price, high quality substrates needed for the thin film growth technology.

Contributions of electron microscopy to the understanding of reactions on compound semiconductor surfaces

International Nuclear Information System (INIS)

Sands, T.

1986-01-01

Reacted films on compound semiconductor substrates present challenging materials characterization problems which often require the application of transmission electron microscopy (TEM) techniques. In this paper, both the problem - solving potential of the TEM techniques and the limits imposed by preparation of thin film/compound semiconductor TEM specimens are discussed. Studies of the Ni/GaAs, CuCl/aq)/CdS and Pd/GaAs reactions exemplify the role of TEM in identifying and determining the spatial distribution of interface - stabilized polymorphs and new ternary phases (e.g. tetragonal Cu/sub 2/S, Ni/sub 3/GaAs and Pd/sub x/GaAs). These examples also serve to clarify the relationship between TEM and complementary analysis techniques such as Rutherford backscattering spectrometry, Auger electron spectroscopy and glancing-angle x-ray diffraction. In particular, it is argued that a combination of (1) high-spatial-resolution information obtained by TEM and (2) an indication of the ''average'' behavior provided by data from a complementary characterization technique provide the minimum quality and quantity of data necessary to understand most reactions on compound semiconductor substrates

Questing and the application for silicon based ternary compound within ultra-thin layer of SIS intermediate region

International Nuclear Information System (INIS)

Chen, Shumin; Gao, Ming; Wan, Yazhou; Du, Huiwei; Li, Yong; Ma, Zhongquan

2016-01-01

Highlights: • A new kind of functional material with plasticity of dielectric was obtained. • Powerful characterization methods was exploited to determine this ultra-thin layer. • The electronic structures and properties of this intermediate layer were analyzed. • A potential application of this structure were investigated. - Abstract: A silicon based ternary compound was supposed to be solid synthesized with In, Si and O elements by magnetron sputtering of indium tin oxide target (ITO) onto crystal silicon substrate at 250 °C. To make clear the configuration of the intermediate region, a potential method to obtain the chemical bonding of Si with other existing elements was exploited by X-ray photoelectron spectroscopy (XPS) instrument combined with other assisted techniques. The phase composition and solid structure of the interfacial region between ITO and Si substrate were investigated by X-ray diffraction (XRD) and high resolution cross sectional transmission electron microscope (HR-TEM). A photovoltaic device with structure of Al/Ag/ITO/SiOx/p-Si/Al was assembled by depositing ITO films onto the p-Si substrate by using magnetron sputtering. The new matter has been assumed to be a buffer layer for semiconductor-insulator-semiconductor (SIS) photovoltaic device and plays critical role for the promotion of optoelectronic conversion performance from the view point of device physics.

Questing and the application for silicon based ternary compound within ultra-thin layer of SIS intermediate region

Energy Technology Data Exchange (ETDEWEB)

Chen, Shumin; Gao, Ming; Wan, Yazhou; Du, Huiwei; Li, Yong [SHU-SolarE R& D Lab, Department of Physics, Shanghai University, Shanghai 200444 (China); Ma, Zhongquan, E-mail: zqma@shu.edu.cn [SHU-SolarE R& D Lab, Department of Physics, Shanghai University, Shanghai 200444 (China); Instrumental Analysis & Research Center, Shanghai University, Shanghai 200444 (China)

2016-12-01

Highlights: • A new kind of functional material with plasticity of dielectric was obtained. • Powerful characterization methods was exploited to determine this ultra-thin layer. • The electronic structures and properties of this intermediate layer were analyzed. • A potential application of this structure were investigated. - Abstract: A silicon based ternary compound was supposed to be solid synthesized with In, Si and O elements by magnetron sputtering of indium tin oxide target (ITO) onto crystal silicon substrate at 250 °C. To make clear the configuration of the intermediate region, a potential method to obtain the chemical bonding of Si with other existing elements was exploited by X-ray photoelectron spectroscopy (XPS) instrument combined with other assisted techniques. The phase composition and solid structure of the interfacial region between ITO and Si substrate were investigated by X-ray diffraction (XRD) and high resolution cross sectional transmission electron microscope (HR-TEM). A photovoltaic device with structure of Al/Ag/ITO/SiOx/p-Si/Al was assembled by depositing ITO films onto the p-Si substrate by using magnetron sputtering. The new matter has been assumed to be a buffer layer for semiconductor-insulator-semiconductor (SIS) photovoltaic device and plays critical role for the promotion of optoelectronic conversion performance from the view point of device physics.

Enhanced Light Absorption in Fluorinated Ternary Small-Molecule Photovoltaics

Energy Technology Data Exchange (ETDEWEB)

Eastham, Nicholas D. [Department; Dudnik, Alexander S. [Department; Harutyunyan, Boris [Department; Aldrich, Thomas J. [Department; Leonardi, Matthew J. [Department; Manley, Eric F. [Department; Chemical; Butler, Melanie R. [Department; Harschneck, Tobias [Department; Ratner, Mark A. [Department; Chen, Lin X. [Department; Chemical; Bedzyk, Michael J. [Department; Department; Melkonyan, Ferdinand S. [Department; Facchetti, Antonio [Department; Chang, Robert P. H. [Department; Marks, Tobin J. [Department; Department

2017-06-14

Using small-molecule donor (SMD) semiconductors in organic photovoltaics (OPVs) has historically afforded lower power conversion efficiencies (PCEs) than their polymeric counterparts. The PCE difference is attributed to shorter conjugated backbones, resulting in reduced intermolecular interactions. Here, a new pair of SMDs is synthesized based on the diketopyrrolopyrrole-benzodithiophene-diketopyrrolopyrrole (BDT-DPP2) skeleton but having fluorinated and fluorinefree aromatic side-chain substituents. Ternary OPVs having varied ratios of the two SMDs with PC61BM as the acceptor exhibit tunable open-circuit voltages (Vocs) between 0.833 and 0.944 V due to a fluorination-induced shift in energy levels and the electronic “alloy” formed from the miscibility of the two SMDs. A 15% increase in PCE is observed at the optimal ternary SMD ratio, with the short-circuit current density (Jsc) significantly increased to 9.18 mA/cm2. The origin of Jsc enhancement is analyzed via charge generation, transport, and diffuse reflectance measurements, and is attributed to increased optical absorption arising from a maximum in film crystallinity at this SMD ratio, observed by grazing incidence wide-angle X-ray scattering.

Ternary superconductors

International Nuclear Information System (INIS)

Giorgi, A.L.

1987-01-01

Ternary superconductors constitute a class of superconducting compounds with exceptional properties such as high transition temperatures (≅ 15.2 K), extremely high critical fields (H c2 >60 Tesla), and the coexistence of superconductivity and long-range magnetic order. This has generated great interest in the scientific community and resulted in a large number of experimental and theoretical investigations in which many new ternary compounds have been discovered. A review of some of the properties of these ternary compounds is presented with particular emphasis on the ternary molybdenum chalcogenides and the ternary rare earth transition metal tetraborides. The effect of partial substitution of a second metal atom to form pseudoternary compounds is examined as well as some of the proposed correlations between the superconducting transition temperature and the structural and electronic properties of the ternary superconductors

Hydrothermal synthesis of 3D urchin-like Ag/TiO_2/reduced graphene oxide composites and its enhanced photocatalytic performance

International Nuclear Information System (INIS)

Liu, Yuhuan; Zhou, Yi; Yang, Luyue; Wang, Yutang; Wu, Yiwei; Li, Chaocheng; Lu, Jun

2016-01-01

Innovative 3D urchin-like ternary TiO_2 composites, which combine Ag nanoparticles with graphene, have been successfully synthesized through a simple hydrothermal method. This process employed nontoxic and mild dihydrate sodium citrate as a reducing agent. During the hydrothermal process, graphene oxide and AgNO_3 were reduced to reduced graphene oxide (RGO) and Ag, respectively. Subsequently, they were grown on the surface of rutile TiO_2 with a 3D urchin-like microsphere (1.5 μm). The as-prepared 3D urchin-like composites were characterized by X-ray diffraction, SEM and TEM. These techniques were also employed to ensure the morphology of urchin-like and rutile phase of TiO_2. FT-IR, Raman spectroscopy and XPS characterization demonstrated the successful reduction in AgNO_3 and graphite oxide to metallic Ag and RGO. The UV–visible spectrum of the ternary composite displayed strong absorption in the visible light region, which was attributed to the efficient electron transport of well-dispersed Ag nanoparticles (20–40 nm) and the formation of Ti–O–C bond between graphene and titania. The synthesized urchin-like ternary composite exhibited enhanced photocatalytic activity (98.7 %) for Rhodamine B degradation. This work provides a very convenient chemical route to the scalable production of Ag/TiO_2/RGO ternary composite photocatalyst for potential applications in solving the environmental problems and energy issues. Also, the proposed mechanism underlying the photocatalytic degradation of Rhodamine B dyes was discussed.Graphical AbstractFourier transform infrared (FTIR) spectra of pure UT, UTG and Ag–UTG composite. The scheme of proposed mechanism for the photocatalytic degradation of RhB on Ag–UTG.

Two Dimensional Effective Electron Mass at the Fermi Level in Quantum Wells of III-V, Ternary and Quaternary Semiconductors.

Science.gov (United States)

Chakrabarti, S; Chatterjee, B; Debbarma, S; Ghatak, K P

2015-09-01

In this paper we study the influence of strong electric field on the two dimensional (2D)effective electron mass (EEM) at the Fermi level in quantum wells of III-V, ternary and quaternary semiconductors within the framework of k x p formalism by formulating a new 2D electron energy spectrum. It appears taking quantum wells of InSb, InAs, Hg(1-x)Cd(x)Te and In(1-x)Ga(x)As(1-y)P(y) lattice matched to InP as examples that the EEM increases with decreasing film thickness, increasing electric field and increases with increasing surface electron concentration exhibiting spikey oscillations because of the crossing over of the Fermi level by the quantized level in quantum wells and the quantized oscillation occurs when the Fermi energy touches the sub-band energy. The electric field makes the mass quantum number dependent and the oscillatory mass introduces quantum number dependent mass anisotropy in addition to energy. The EEM increases with decreasing alloy composition where the variations are totally band structure dependent. Under certain limiting conditions all the results for all the cases get simplified into the well-known parabolic energy bands and thus confirming the compatibility test. The content of this paper finds three applications in the fields of nano-science and technology.

Stable and metastable phases in reciprocal systems PbSe + Ag2I2 Ag2Se + PbI2 and PbSe + CdI2 = CdSe + PbI2

International Nuclear Information System (INIS)

Odin, I.N.; Grin'ko, V.V.; Kozlovskij, V.F.; Safronov, E.V.

2005-01-01

Mutual system PbSe + Ag 2 I 2 = Ag 2 Se + PbI 2 is investigated. It is shown that diagonal Ag 2 Se-PbI 2 is stable. Liquidus surface and isothermal section at 633 K of phase diagram of PbSe-Ag 2 Se-PbI 2 system are built. Transformations directing to crystallization metastable ternary compound forming in PbSe-PbI 2 system and metastable polytype modifications of lead iodide in PbSe-Ag 2 Se-PbI 2 system at 620-685 K are studied. By hardening from molten state (1150-1220 K) new interstitial metastable phases crystallizing in CdCl 2 structural type are obtained in PbSe-Ag 2 Se-PbI 2 and PbSe + CdI 2 = CdSe + PbI 2 systems [ru

Magnetism in the p-type Monolayer II-VI semiconductors SrS and SrSe

Science.gov (United States)

Lin, Heng-Fu; Lau, Woon-Ming; Zhao, Jijun

2017-01-01

Using density functional theory calculations, we study the electronic and magnetic properties of the p-type monolayer II-VI semiconductors SrX (X = S,Se). The pristine SrS and SrSe monolayers are large band gap semiconductor with a very flat band in the top valence band. Upon injecting hole uniformly, ferromagnetism emerges in those system in a large range of hole density. By varying hole density, the systems also show complicated phases transition among nonmagnetic semiconductor, half metal, magnetic semiconductor, and nonmagnetic metal. Furthermore, after introducing p-type dopants in SrS and SrSe via substitutionary inserting P (or As) dopants at the S (or Se) sites, local magnetic moments are formed around the substitutional sites. The local magnetic moments are stable with the ferromagnetic order with appreciable Curie temperature. The ferromagnetism originates from the instability of the electronic states in SrS and SrSe with the large density of states at the valence band edge, which demonstrates a useful strategy for realizing the ferromagnetism in the two dimensional semiconductors. PMID:28378761

Optical and electrical characterization of AgInS2 thin films deposited by spray pyrolysis

International Nuclear Information System (INIS)

Calixto-Rodriguez, M.; Martinez, H.; Calixto, M.E.; Pena, Y.; Martinez-Escobar, Dalia; Tiburcio-Silver, A.; Sanchez-Juarez, A.

2010-01-01

Silver indium sulfide (AgInS 2 ) thin films have been prepared by spray pyrolysis (SP) technique using silver acetate, indium acetate, and N, N-dimethylthiourea as precursor compounds. Films were deposited onto glass substrates at different substrate temperatures (T s ) and Ag:In:S ratios in the starting solutions. Optical transmission and reflection as well as electrical measurements were performed in order to study the effect of deposition parameters on the optical and electrical properties of AgInS 2 thin films. X-ray diffraction measurements were used to identify the deposited compounds. It was found that different compounds such as AgInS 2 , Ag 2 S, In 2 O 3 , and In 2 S 3 can be grown only by changing the Ag:In:S ratio in the starting solution and T s . So that, by carefully selecting the deposition parameters, single phase AgInS 2 thin films can be easily grown. Thin films obtained using a molar ratio of Ag:In:S = 1:1:2 and T s = 400 o C, have an optical band gap of 1.9 eV and n-type electrical conductivity with a value of 0.3 Ω -1 cm -1 in the dark.

Observation of a Ag protrusion on a Ag2S island using a scanning tunneling microscope

Directory of Open Access Journals (Sweden)

Takeo Ohno

2015-01-01

Full Text Available A silver sulfide (Ag2S island as an ionic conductor in resistive switching memories was formed and a protrusion of silver from the Ag2S formed by an electrochemical reaction was observed using a scanning tunneling microscope.

Surface reconstruction of titania with g-C{sub 3}N{sub 4} and Ag for promoting efficient electrons migration and enhanced visible light photocatalysis

Energy Technology Data Exchange (ETDEWEB)

Leong, Kah Hon; Liu, Sze Ling [Environmental Engineering Laboratory, Department of Civil Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Sim, Lan Ching [Faculty of Engineering and Green Technology, Universiti Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, 31900 Kampar, Perak (Malaysia); Saravanan, Pichiah, E-mail: saravananpichiah@um.edu.my [Environmental Engineering Laboratory, Department of Civil Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Nanotechnology & Catalysis Research Center (NANOCAT), University of Malaya, 50603 Kuala Lumpur (Malaysia); Jang, Min [Environmental Engineering Laboratory, Department of Civil Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Nanotechnology & Catalysis Research Center (NANOCAT), University of Malaya, 50603 Kuala Lumpur (Malaysia); Ibrahim, Shaliza [Environmental Engineering Laboratory, Department of Civil Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2015-12-15

Graphical abstract: - Highlights: • Visible light responsive TiO{sub 2} was reconstructed with g-C{sub 3}N{sub 4} and Ag by simple route. • g-C{sub 3}N{sub 4} simultaneously promoted electrons migration and tuned energy gap of TiO{sub 2}. • Ag facilitated electron junction and enhanced the visible light through SPR. • Reconstructed TiO{sub 2} showed an excellent photocatalytic performance by removing AMX. - Abstract: The developments of heterogeneous photocatalysts are one among the competent reconstruction approach to enrich the visible light responsiveness of conventional TiO{sub 2}. In the present work the TiO{sub 2} was reconstructed with graphitic carbon nitride (g-C{sub 3}N{sub 4}) and silver (Ag) to form a ternary (g-C{sub 3}N{sub 4})–Ag/TiO{sub 2}. The graphitic carbon nitride an intriguing material was prepared through a facile pyrolysis by using urea as a precursor. The silver (Ag) that plays a role as electron-conduction mobiliser in the ternary was synthesised through solar mediated photodeposition method. The synthesised ternary composite characteristics were thoroughly investigated through various physical and chemical analyses. The presence of g-C{sub 3}N{sub 4} in the ternary photocatalysts promoted the formation of interface between the Ag/TiO{sub 2} and g-C{sub 3}N{sub 4} and stimulated the electron transfer between them. These electrons migration acknowledged by the synergic effect prolonged the lifetime of charge carriers. The g-C{sub 3}N{sub 4} also significantly tuned the energy band of conventional TiO{sub 2}. The prepared ternary exhibited significantly high visible light photocatalytic performance by degrading Amoxicillin (AMX) a poor photosensitising pollutant at highest rate.

Hydrothermal synthesis of 3D urchin-like Ag/TiO{sub 2}/reduced graphene oxide composites and its enhanced photocatalytic performance

Energy Technology Data Exchange (ETDEWEB)

Liu, Yuhuan; Zhou, Yi, E-mail: zhouyihn@aliyun.com, E-mail: zhouyihn@163.com; Yang, Luyue [Changsha University of Science and Technology, Department of Chemical and Biological Engineering (China); Wang, Yutang [Changsha University, Hunan Province Key Laboratory of Applied Environmental Photocatalysis (China); Wu, Yiwei; Li, Chaocheng; Lu, Jun [Changsha University of Science and Technology, Department of Chemical and Biological Engineering (China)

2016-09-15

Innovative 3D urchin-like ternary TiO{sub 2} composites, which combine Ag nanoparticles with graphene, have been successfully synthesized through a simple hydrothermal method. This process employed nontoxic and mild dihydrate sodium citrate as a reducing agent. During the hydrothermal process, graphene oxide and AgNO{sub 3} were reduced to reduced graphene oxide (RGO) and Ag, respectively. Subsequently, they were grown on the surface of rutile TiO{sub 2} with a 3D urchin-like microsphere (1.5 μm). The as-prepared 3D urchin-like composites were characterized by X-ray diffraction, SEM and TEM. These techniques were also employed to ensure the morphology of urchin-like and rutile phase of TiO{sub 2}. FT-IR, Raman spectroscopy and XPS characterization demonstrated the successful reduction in AgNO{sub 3} and graphite oxide to metallic Ag and RGO. The UV–visible spectrum of the ternary composite displayed strong absorption in the visible light region, which was attributed to the efficient electron transport of well-dispersed Ag nanoparticles (20–40 nm) and the formation of Ti–O–C bond between graphene and titania. The synthesized urchin-like ternary composite exhibited enhanced photocatalytic activity (98.7 %) for Rhodamine B degradation. This work provides a very convenient chemical route to the scalable production of Ag/TiO{sub 2}/RGO ternary composite photocatalyst for potential applications in solving the environmental problems and energy issues. Also, the proposed mechanism underlying the photocatalytic degradation of Rhodamine B dyes was discussed.Graphical AbstractFourier transform infrared (FTIR) spectra of pure UT, UTG and Ag–UTG composite. The scheme of proposed mechanism for the photocatalytic degradation of RhB on Ag–UTG.

Photoelectrochemical processes in organic semiconductor: Ambipolar perylene diimide thin film

Science.gov (United States)

Kim, Jung Yong; Chung, In Jae

2018-03-01

A thin film of N,N‧-dioctadecyl-3,4,9,10-perylene tetracarboxylic diimide (PTCDI-C18) is spin-coated on indium tin oxide (ITO) glass. Using the PTCDI-C18/ITO electrode, we fabricate a photoelectrochemical cell with the ITO/PTCDI-C18/Redox Electrolyte/Pt configuration. The electrochemical properties of this device are investigated as a function of hydroquinone (HQ) concentration, bias voltage, and wavelength of light. Anodic photocurrent is observed at V ≥ -0.2 V vs. Ag/AgCl, indicating that the PTCDI-C18 film acts as an n-type semiconductor as usual. However, when benzoquinone (BQ) is inserted into the electrolyte system instead of HQ, cathodic photocurrent is observed at V ≤ 0.0 V, displaying that PTCDI-C18 abnormally serves as a p-type semiconductor. Hence the overall results reveal that the PTCDI-C18 film can be an ambipolar functional semiconductor depending on the redox couple in the appropriate voltage.

True ternary fission in 310126X

International Nuclear Information System (INIS)

Banupriya, B.; Vijayaraghavan, K.R.; Balasubramaniam, M.

2015-01-01

All possible combinations are minimized by the two dimensional minimization process and minimized with respect to neutron numbers and proton numbers of the fragments. Potential energy is low and Q - value is high at true ternary fission region. It shows that true ternary mode is the dominant mode in the ternary fission of superheavy nuclei. Also, the results show that the fragments with neutron magic numbers are the dominant one in the ternary fission of superheavy nuclei whereas the fragments with proton magic numbers are the dominant one in the ternary fission of heavy nuclei

Quadratite, AgCdAsS₃

DEFF Research Database (Denmark)

Bindi, Luca; Spry, Paul G.; Bonazzi, Paola

2013-01-01

of BAB slabs [A: (Cd,Ag)CdS2 atomic plane; B: (Ag,Pb)AsS2 atomic plane] along [001]. The rectangular unit cell of these slabs is oriented diagonally to the a axes of quadratite and consecutive slabs are related via interlayer twofold rotation operations parallel either to [100] or to [010...

Sulfurization of sputtered Ag–In precursors for AgInS{sub 2} solar cell absorber layers

Energy Technology Data Exchange (ETDEWEB)

Anantha Sunil, M. [Energy and Health Monitoring Instrumentation Laboratory, Department of Instrumentation & Applied Physics, Indian Institute of Science, Bangalore 560012 (India); Thota, Narayana [Advanced Materials Research Laboratory, Department of Physics, Yogi Vemana University, Kadapa 516003 (India); Deepa, K.G. [Energy and Health Monitoring Instrumentation Laboratory, Department of Instrumentation & Applied Physics, Indian Institute of Science, Bangalore 560012 (India); Jampana, Nagaraju, E-mail: solarjnr@gmail.com [Energy and Health Monitoring Instrumentation Laboratory, Department of Instrumentation & Applied Physics, Indian Institute of Science, Bangalore 560012 (India)

2015-11-30

Silver indium sulfide (AgInS{sub 2}) thin films are deposited by sequential sputtering of metallic precursor [Ag/In] followed by sulfurization. Effect of substrate temperature (T{sub sub}) during sulfurization process on the film growth is studied by varying the substrate temperature from 350 to 500 °C. Films prepared above 350 °C showed a mixture of orthorhombic and tetragonal phases of AgInS{sub 2} with tetragonal phase being dominant. Better crystalline, nearly stoichiometric and p-type films are obtained at a substrate temperature of 500 °C. The characteristic A{sub 1} mode of AgInS{sub 2} chalcopyrite structure is observed in the Raman spectra at 274 cm{sup −1} for the films prepared above 350 °C. The grain size of the film increases from 489 to 895 nm with the increase in substrate temperature. The binding energies of the constituent elements are determined using XPS. The band gap of AgInS{sub 2} films is in the range of 1.64–1.92 eV and the absorption coefficient is found to be > 10{sup 4} cm{sup −1}. Preliminary studies on the AgInS{sub 2}/ZnS solar cell showed an efficiency of 0.3%. - Highlights: • AgInS{sub 2} films are grown by sulfurization of sputtered metal precursors. • Effect of substrate temperature on the growth of AgInS{sub 2} films is studied. • Films sulfurized at 500 °C have the best structural and opto-electrical properties. • AgInS{sub 2}/ZnS solar cell has been fabricated with an efficiency of ~ 0.3%.

Structural and electronic properties of Ga{sub 1-x}In{sub x} As{sub 1-y}N{sub y} quaternary semiconductor alloy on GaAs substrate

Energy Technology Data Exchange (ETDEWEB)

Aslan, Metin, E-mail: maslan@sakarya.edu.tr [Sakarya University, Art, Science Faculty, Department of Physics, Esentepe Campus, 54187 Sakarya (Turkey); Yalc Latin-Small-Letter-Dotless-I n, Battal G.; Uestuendag, Mehmet [Sakarya University, Art, Science Faculty, Department of Physics, Esentepe Campus, 54187 Sakarya (Turkey)

2012-04-05

Highlights: Black-Right-Pointing-Pointer In this study we used DFT in the frame of LDA approach to determine electronic and structural properties of GaInAsN alloy. Black-Right-Pointing-Pointer We calculated lattice parameter and band gap energy of binary (GaAs, InAs, and GaN), ternary (GaInAs, GaAsN) and quaternary (GaInAsN) semiconductor alloys. Black-Right-Pointing-Pointer We formulated lattice parameter of GaInAsN respect to In and N composition. Black-Right-Pointing-Pointer We investigated different In and N composition of GaInAsN/GaAs heterostructure for various device applications. - Abstract: We have presented structural and electronic properties of binary (GaAs, GaN and InAs), ternary (Ga{sub 1-x}In{sub x}As and GaAs{sub 1-y}N{sub y}) and quaternary (Ga{sub 1-x}In{sub x}As{sub 1-y}N{sub y}) semiconductor alloys by using a first-principles pseudopotential technique. The structural and electronic properties of Zinc-Blende phase of these materials have been calculated by using the local density approximation (LDA) of the density-functional theory (DFT). To obtain the lattice parameter and band gap energy of the (GaInAsN) quaternary semiconductor alloy we separately calculated the lattice constant and band gap energies of ternary semiconductor alloys, namely GaAsN and GaInAs. The calculated lattice constant, bulk modulus and the direct band gaps for studied semiconductors showed great parallelism with the previous available theoretical and experimental studies.

Effect of fluctuations on electron and phonon processes and thermodynamic parameters of Ag2Te and Ag2Se in the region of phase transition

International Nuclear Information System (INIS)

Aliev, S. A.; Aliev, F. F.

2008-01-01

Temperature dependences of electrical conductivity σ, thermoelectric power α, results of differential thermal analysis ΔT y , thermal conductivity χ, temperature conductivity κ, and heat capacity C p were studied in Ag 2 Te and Ag 2 Se semiconductors in the region of the phase transition. Two extrema are observed in the temperature dependence χ(T): a maximum in the region of the α' → β' transition and a minimum in the region of the β' → β transition; these extrema are caused by the similar dependence C p (T). It is shown that the α → α' and β' → β transitions are displacement transitions, while the α' → β' transition is of reconstruction type. It is established that the disorder parameter η in silver chalcogenides is highly smeared in the region of the phase transition; therefore, disordering of phases at the point of the phase transition is incomplete: 73, 62, and 48% in Ag 2 Te, Ag 2 Se, and Ag 2 S, respectively. The minimum volumes V ph for new phases are calculated; it is shown that the value of V ph in displacement transitions is larger than in the reconstruction-type transitions

Band gap characterization of ternary BBi1−xNx (0≤x≤1) alloys using modified Becke–Johnson (mBJ) potential

International Nuclear Information System (INIS)

Yalcin, Battal G.

2015-01-01

The semi-local Becke–Johnson (BJ) exchange-correlation potential and its modified form proposed by Tran and Blaha have attracted a lot of interest recently because of the surprisingly accurate band gaps they can deliver for many semiconductors and insulators (e.g., sp semiconductors, noble-gas solids, and transition-metal oxides). The structural and electronic properties of ternary alloys BBi 1−x N x (0≤x≤1) in zinc-blende phase have been reported in this study. The results of the studied binary compounds (BN and BBi) and ternary alloys BBi 1−x N x structures are presented by means of density functional theory. The exchange and correlation effects are taken into account by using the generalized gradient approximation (GGA) functional of Wu and Cohen (WC) which is an improved form of the most popular Perdew–Burke–Ernzerhof (PBE). For electronic properties the modified Becke–Johnson (mBJ) potential, which is more accurate than standard semi-local LDA and PBE calculations, has been chosen. Geometric optimization has been implemented before the volume optimization calculations for all the studied alloys structure. The obtained equilibrium lattice constants of the studied binary compounds are in coincidence with experimental works. And, the variation of the lattice parameter of ternary alloys BBi 1−x N x almost perfectly matches with Vegard's law. The spin–orbit interaction (SOI) has been also considered for structural and electronic calculations and the results are compared to those of non-SOI calculations

Electrical conductivity studies in (Ag3AsS3)x(As2S3)1-x superionic glasses and composites

Science.gov (United States)

Studenyak, I. P.; Neimet, Yu. Yu.; Kranjčec, M.; Solomon, A. M.; Orliukas, A. F.; Kežionis, A.; Kazakevičius, E.; Šalkus, T.

2014-01-01

Compositional, frequency, and temperature studies of impedance and electrical conductivity in (Ag3AsS3)x(As2S3)1-x superionic glasses and composites were performed. Frequency range from 10 Hz to 3 × 109 Hz and temperature interval 300-400 K were used for the measurements. Compositional dependences of electrical conductivity and activation energy are analyzed; the most substantial changes are observed with the transition from (Ag3AsS3)0.4(As2S3)0.6 glass to (Ag3AsS3)0.5(As2S3)0.5 composite. With increase of Ag3AsS3 content, the investigated materials are found to have crystalline inclusions and show the two-phase composite nature. Addition of Ag3AsS3 leads to the increase of electrical conductivity whereas the activation energy decreases.

Metal ion displacements in noncentrosymmetric chalcogenides La{sub 3}Ga{sub 1.67}S{sub 7}, La{sub 3}Ag{sub 0.6}GaCh{sub 7} (Ch=S, Se), and La{sub 3}MGaSe{sub 7} (M=Zn, Cd)

Energy Technology Data Exchange (ETDEWEB)

Iyer, Abishek K. [Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G2G2 (Canada); Yin, Wenlong [Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G2G2 (Canada); Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang 621900 (China); Rudyk, Brent W. [Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G2G2 (Canada); Lin, Xinsong [Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G2G2 (Canada); Centre for Oil Sands Sustainability, Northern Alberta Institute of Technology, Edmonton, Alberta, Canada T6N1E5 (Canada); Nilges, Tom [Department of Chemistry, Technical University of Munich, 85748 Garching b. München (Germany); Mar, Arthur, E-mail: arthur.mar@ualberta.ca [Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G2G2 (Canada)

2016-11-15

The quaternary Ga-containing chalcogenides La{sub 3}Ag{sub 0.6}GaS{sub 7}, La{sub 3}Ag{sub 0.6}GaSe{sub 7}, La{sub 3}ZnGaSe{sub 7}, and La{sub 3}CdGaSe{sub 7}, as well as the related ternary chalcogenide La{sub 3}Ga{sub 1.67}S{sub 7}, were prepared by reactions of the elements at 950 °C. They adopt noncentrosymmetric hexagonal structures (space group P6{sub 3}, Z=2) with cell parameters (a=10.2 Å, c=6.1 Å for the sulfides; a=10.6 Å, c=6.4 Å for the selenides) that are largely controlled by the geometrical requirements of one-dimensional stacks of Ga-centered tetrahedra separated by the La atoms. Among these compounds, which share the common formulation La{sub 3}M{sub 1–x}GaCh{sub 7} (M=Ga, Ag, Zn, Cd; Ch=S, Se), the M atoms occupy sites within a stacking of trigonal antiprisms formed by Ch atoms. The location of the M site varies between extremes with trigonal antiprismatic (CN6) and trigonal planar (CN3) geometry. Partial occupation of these sites and intermediate ones accounts for the considerable versatility of these structures and the occurrence of large metal displacement parameters. The site occupations can be understood in a simple way as being driven by the need to satisfy appropriate bond valence sums for both the M and Ch atoms. Band structure calculations rationalize the substoichiometry observed in the Ag-containing compounds (La{sub 3}Ag{sub 0.6}GaS{sub 7}, La{sub 3}Ag{sub 0.6}GaSe{sub 7}) as a response to overbonding. X-ray photoelectron spectroscopy supports the presence of monovalent Ag atoms in these compounds, which are not charge-balanced. - Graphical abstract: Partial occupation of metal atoms in multiple sites accounts for versatility in Ga-containing chalcogenides La{sub 3}M{sub 1–x}GaCh{sub 7} with noncentrosymmetric hexagonal structures. - Highlights: • La{sub 3}M{sub 1–x}GaCh{sub 7} (M =Ga, Ag, Zn, Cd; Ch =S, Se) adopt related hexagonal structures. • Large displacements of M atoms originate from partial occupation of multiple

Optical and electrical characterization of AgInS{sub 2} thin films deposited by spray pyrolysis

Energy Technology Data Exchange (ETDEWEB)

Calixto-Rodriguez, M., E-mail: manuela@fis.unam.mx [Instituto de Ciencias Fisicas-Universidad Nacional Autonoma de Mexico, Apartado Postal 48-3, 62210, Cuernavaca, Morelos (Mexico); Martinez, H. [Instituto de Ciencias Fisicas-Universidad Nacional Autonoma de Mexico, Apartado Postal 48-3, 62210, Cuernavaca, Morelos (Mexico); Calixto, M.E. [Instituto de Fisica, Benemerita Universidad Autonoma de Puebla, Apartado Postal J-48, 72570, Puebla, Puebla (Mexico); Pena, Y. [Facultad de Ciencias Quimicas, Universidad Autonoma de Nuevo Leon, Pedro de Alba s/n, Ciudad Universitaria, 66451, San Nicolas de los Garza, Nuevo Leon (Mexico); Martinez-Escobar, Dalia [Centro de Investigacion en Energia-Universidad Nacional Autonoma de Mexico, 62580, Temixco, Morelos (Mexico); Tiburcio-Silver, A. [Instituto Tecnologico de Toluca-SEP, Apartado Postal 20, 52176, Metepec 3, Estado de Mexico (Mexico); Sanchez-Juarez, A. [Centro de Investigacion en Energia-Universidad Nacional Autonoma de Mexico, 62580, Temixco, Morelos (Mexico)

2010-10-25

Silver indium sulfide (AgInS{sub 2}) thin films have been prepared by spray pyrolysis (SP) technique using silver acetate, indium acetate, and N, N-dimethylthiourea as precursor compounds. Films were deposited onto glass substrates at different substrate temperatures (T{sub s}) and Ag:In:S ratios in the starting solutions. Optical transmission and reflection as well as electrical measurements were performed in order to study the effect of deposition parameters on the optical and electrical properties of AgInS{sub 2} thin films. X-ray diffraction measurements were used to identify the deposited compounds. It was found that different compounds such as AgInS{sub 2}, Ag{sub 2}S, In{sub 2}O{sub 3}, and In{sub 2}S{sub 3} can be grown only by changing the Ag:In:S ratio in the starting solution and T{sub s}. So that, by carefully selecting the deposition parameters, single phase AgInS{sub 2} thin films can be easily grown. Thin films obtained using a molar ratio of Ag:In:S = 1:1:2 and T{sub s} = 400 {sup o}C, have an optical band gap of 1.9 eV and n-type electrical conductivity with a value of 0.3 {Omega}{sup -1} cm{sup -1} in the dark.

The 4s24p3-4s4p4 transition in AsI-like AgXV

International Nuclear Information System (INIS)

Dong Chenzhong; Zhao Jinbao

1992-01-01

Some terms of the 4s 4p 4 configuration in RuXII, RhXIII and PdXIV ions can be improved and all the energy values of the configuration in AgXV can be predicted theoretically by means of a configuration-interaction ab initio analysis for the level structure of the 4s 4p 4 configuration along the AsI sequence of KrIV-AgXV ions. Calculations of the wavelengths and oscillator strenghts are presented for the 4s 2 4p 3 -4s 4p 4 transition in AgXV. (orig.)

Preparation and optical properties of AgGaS{sub 2} nanofilms

Energy Technology Data Exchange (ETDEWEB)

Zhang, Jianjun [School of Materials Sci. and Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Huang, Yi [School of Electronic and Information Engineering, Southwest University for Nationalities, Chengdu 610041 (China)

2011-05-15

In this paper, AgGaS{sub 2} nanofilms have been prepared by a two-step process involving the successive ionic layer absorption and reaction (SILAR) and annealing method. Using AgNO{sub 3}, GaCl{sub 3} and Na{sub 2}S{sub 2}O{sub 3} as reaction sources, the mixture films were firstly deposited on quartz glass substrates at room temperature, and then annealed in Ar environment at 200-500 C for 4 h, respectively. The effects of annealing temperature on structural and optical properties were investigated by XRD, UV-Vis, EDS and photoluminescence (PL) spectra. It was revealed in XRD results that {alpha}-Ag{sub 9}GaS{sub 6} was contained in the samples annealed at 200 C, and this phase was decreased with increase of the annealing temperatures. When the sample was annealed at above 400 C, the chalcopyrite AgGaS{sub 2} nanofilm was obtained. The preferred orientation was exhibited along the (112) plane. It was shown in atomic force microscopy (AFM) results that the grain sizes in AgGaS{sub 2} nanofilms were 18-24 nm and the thin films were smooth and strongly adherent to the substrates. When the annealing temperature was higher than 400 C, it is an optimum condition to improve the structural and optical properties of the AgGaS{sub 2} thin films. The room temperature PL spectra of AgGaS{sub 2} nanofilms showed prominent band edge emission at 2.72 eV. Based on all results mentioned above, it can be concluded that the SILAR-annealing method is preferable to preparing high-quality AgGaS{sub 2} nanofilms. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Deviations from Vegard’s law in ternary III-V alloys

KAUST Repository

Murphy, S. T.; Chroneos, Alexander; Grimes, R. W.; Jiang, C.; Schwingenschlö gl, Udo

2010-01-01

the linear relationship would predict. Here we use special quasirandom structures and density functional theory to investigate such deviations for MxN1−xAs ternary alloys, where M and N are group III species (B, Al, Ga, and In). Our simulations predict a

Microstructure of III-N semiconductors related to their applications in optoelectronics

Science.gov (United States)

Leszczynski, M.; Czernetzki, R.; Sarzynski, M.; Krysko, M.; Targowski, G.; Prystawko, P.; Bockowski, M.; Grzegory, I.; Suski, T.; Domagala, J.; Porowski, S.

2005-03-01

There has been more than a decade since Shuji Nakamura from Japanese company Nichia constructed the first blue LED based on structure of (AlGaIn)N semiconductor and eight years since he made the first blue laser diode (LD). This work gives a survey on the current technological status with green/blue/violet/UV optoelectronics based on III-N semiconductors in relation with their microstructure. The following devices are presented: i) Low-power green and blue LEDs, ii) High-power LEDs targeting solid-state white lighting, iii) Low-power violet LDs for high definition DVD market, iv) High-power violet LDs, v) UV LEDs. The discussion will be focused on three main technological problems related to the microstructure of (AlGaIn)N layers in emitters based on III-N semiconductors: i) high density of dislocations in epitaxial layers of GaN on foreign substrates (sapphire, SiC, GaAs), ii), presence of strains, iii) atom segregation in ternary and quaternary compounds.

Quantum dot sensitized solar cell based on TiO2/CdS/Ag2S heterostructure

Science.gov (United States)

Pawar, Sachin A.; Patil, Dipali S.; Kim, Jin Hyeok; Patil, Pramod S.; Shin, Jae Cheol

2017-04-01

Quantum dot sensitized solar cell (QDSSC) is fabricated based on a stepwise band structure of TiO2/CdS/Ag2S to improve the photoconversion efficiency of TiO2/CdS system by incorporating a low band gap Ag2S QDs. Vertically aligned TiO2 nanorods assembly is prepared by a simple hydrothermal technique. The formation of CdS and Ag2S QDs over TiO2 nanorods assembly as a photoanode is carried out by successive ionic layer adsorption and reaction (SILAR) technique. The synthesized electrode materials are characterized by XRD, XPS, field emission scanning electron microscopy (FE-SEM), Optical, solar cell and electrochemical performances. The results designate that the QDs of CdS and Ag2S have efficiently covered exterior surfaces of TiO2 nanorods assembly. A cautious evaluation between TiO2/CdS and TiO2/CdS/Ag2S sensitized cells tells that CdS and Ag2S synergetically helps to enhance the light harvesting ability. Under AM 1.5G illumination, the photoanodes show an improved power conversion efficiency of 1.87%, in an aqueous polysulfide electrolyte with short-circuit photocurrent density of 7.03 mA cm-2 which is four fold higher than that of a TiO2/CdS system.

Ag/PEPC/NiPc/ZnO/Ag thin film capacitive and resistive humidity sensors

International Nuclear Information System (INIS)

Karimov, Kh. S.; Saleem, M.; Murtaza, Imran; Farooq, M.; Cheong, Kuan Yew; Noor, Ahmad Fauzi Mohd

2010-01-01

A thin film of blended poly-N-epoxypropylcarbazole (PEPC) (25 wt.%), nickel phthalocyanine (NiPc) (50 wt.%) and ZnO nano-powder (25 wt.%) in benzene (5 wt.%) was spin-coated on a glass substrate with silver electrodes to produce a surface-type Ag/PEPC/NiPc/ZnO/Ag capacitive and resistive sensor. Sensors with two different PEPC/NiPc/ZnO film thicknesses (330 and 400 nm) were fabricated and compared. The effects of humidity on capacitance and resistance of the Ag/PEPC/NiPc/ZnO/Ag sensors were investigated at two frequencies of the applied voltage: 120 Hz and 1 kHz. It was observed that at 120 Hz under humidity of up to 95% RH the capacitance of the sensors increased by 540 times and resistance decreased by 450 times with respect to humidity conditions of 50% RH. It was found that the sensor with a thinner semiconducting film (330 nm) was more sensitive than the sensor with a thicker film (400 nm). The sensitivity was improved when the sensor was used at a lower frequency as compared with a high frequency. It is assumed that the humidity response of the sensors is associated with absorption of water vapors and doping of water molecules in the semiconductor blend layer. This had been proven by simulation of the capacitance-humidity relationship. (semiconductor devices)

Ternary fission

International Nuclear Information System (INIS)

Wagemans, C.

1991-01-01

Since its discovery in 1946, light (charged) particle accompanied fission (ternary fission) has been extensively studied, for spontaneous as well as for induced fission reactions. The reason for this interest was twofold: the ternary particles being emitted in space and time close to the scission point were expected to supply information on the scission point configuration and the ternary fission process was an important source of helium, tritium, and hydrogen production in nuclear reactors, for which data were requested by the nuclear industry. Significant experimental progress has been realized with the advent of high-resolution detectors, powerful multiparameter data acquisition systems, and intense neutron and photon beams. As far as theory is concerned, the trajectory calculations (in which scission point parameters are deduced from the experimental observations) have been very much improved. An attempt was made to explain ternary particle emission in terms of a Plateau-Rayleigh hydrodynamical instability of a relatively long cylindrical neck or cylindrical nucleus. New results have also been obtained on the so-called open-quotes trueclose quotes ternary fission (fission in three about-equal fragments). The spontaneous emission of charged particles has also clearly been demonstrated in recent years. This chapter discusses the main characteristics of ternary fission, theoretical models, light particle emission probabilities, the dependence of the emission probabilities on experimental variables, light particle energy distributions, light particle angular distributions, correlations between light particle accompanied fission observables, open-quotes trueclose quotes ternary fission, and spontaneous emission of heavy ions. 143 refs., 18 figs., 8 tabs

Dependence of nonlinear optical properties of Ag2S@ZnS core-shells on Zinc precursor and capping agent

Science.gov (United States)

Dehghanipour, M.; Khanzadeh, M.; Karimipour, M.; Molaei, M.

2018-03-01

In this research, four different types of Ag2S@ZnS core-shells were synthesized and their nonlinear optical (NLO) properties were investigated using a Z-scan technique by a 532 nm laser diode. Here, Ag2S and ZnS nanoparticles were also synthesized and their NLO properties were compared with Ag2S@ZnS core-shells. It was observed that the NLO properties of Ag2S@ZnS quantum dots significantly increased by increasing the values of Zn(NO3)2 and thioglycolic acid (TGA). It was also observed that the NLO properties of Ag2S@ZnS core-shells for 0.1 g of Zn(NO3)2 and 7000 μl TGA is higher than sole Ag2S and ZnS nanoparticles. In open aperture Z-scan curve of ZnS sample, a saturable absorption peak was observed and this peak was seen also in type of Ag2S@ZnS nanoparticles which the value of Zn(NO3)2 much more.

Room Temperature Hard Radiation Detectors Based on Solid State Compound Semiconductors: An Overview

Science.gov (United States)

Mirzaei, Ali; Huh, Jeung-Soo; Kim, Sang Sub; Kim, Hyoun Woo

2018-05-01

Si and Ge single crystals are the most common semiconductor radiation detectors. However, they need to work at cryogenic temperatures to decrease their noise levels. In contrast, compound semiconductors can be operated at room temperature due to their ability to grow compound materials with tunable densities, band gaps and atomic numbers. Highly efficient room temperature hard radiation detectors can be utilized in biomedical diagnostics, nuclear safety and homeland security applications. In this review, we discuss room temperature compound semiconductors. Since the field of radiation detection is broad and a discussion of all compound materials for radiation sensing is impossible, we discuss the most important materials for the detection of hard radiation with a focus on binary heavy metal semiconductors and ternary and quaternary chalcogenide compounds.

Room Temperature Hard Radiation Detectors Based on Solid State Compound Semiconductors: An Overview

Science.gov (United States)

Mirzaei, Ali; Huh, Jeung-Soo; Kim, Sang Sub; Kim, Hyoun Woo

2018-03-01

Si and Ge single crystals are the most common semiconductor radiation detectors. However, they need to work at cryogenic temperatures to decrease their noise levels. In contrast, compound semiconductors can be operated at room temperature due to their ability to grow compound materials with tunable densities, band gaps and atomic numbers. Highly efficient room temperature hard radiation detectors can be utilized in biomedical diagnostics, nuclear safety and homeland security applications. In this review, we discuss room temperature compound semiconductors. Since the field of radiation detection is broad and a discussion of all compound materials for radiation sensing is impossible, we discuss the most important materials for the detection of hard radiation with a focus on binary heavy metal semiconductors and ternary and quaternary chalcogenide compounds.

Ternary semiconductors NiZrSn and CoZrBi with half-Heusler structure: A first-principles study

Science.gov (United States)

Fiedler, Gregor; Kratzer, Peter

2016-08-01

The ternary semiconductors NiZrSn and CoZrBi with C 1b crystal structure are introduced by calculating their basic structural, electronic, and phononic properties using density functional theory. Both the gradient-corrected PBE functional and the hybrid functional HSE06 are employed. While NiZrSn is found to be a small-band-gap semiconductor (Eg=0.46 eV in PBE and 0.60 eV in HSE06), CoZrBi has a band gap of 1.01 eV in PBE (1.34 eV in HSE06). Moreover, effective masses and deformation potentials are reported. In both materials A B C , the intrinsic point defects introduced by species A (Ni or Co) are calculated. The Co-induced defects in CoZrBi are found to have a higher formation energy compared to Ni-induced defects in NiZrSn. The interstitial Ni atom (Nii) as well as the VNiNii complex introduce defect states in the band gap, whereas the Ni vacancy (VNi) only reduces the size of the band gap. While Nii is electrically active and may act as a donor, the other two types of defects may compensate extrinsic doping. In CoZrBi, only the VCoCoi complex introduces a defect state in the band gap. Motivated by the reported use of NiZrSn for thermoelectric applications, the Seebeck coefficient of both materials, both in the p -type and the n -type regimes, is calculated. We find that CoZrBi displays a rather large thermopower of up to 500 μ V /K when p doped, whereas NiZrSn possesses its maximum thermopower in the n -type regime. The reported difficulties in achieving p -type doping in NiZrSn could be rationalized by the unintended formation of Nii2 + in conjunction with extrinsic acceptors, resulting in their compensation. Moreover, it is found that all types of defects considered, when present in concentrations as large as 3%, tend to reduce the thermopower compared to ideal bulk crystals at T =600 K. For NiZrSn, the calculated thermodynamic data suggest that additional Ni impurities could be removed by annealing, leading to precipitation of a metallic Ni2ZrSn phase.

Mechanical properties and dual atmosphere tolerance of Ag-Al based braze

Energy Technology Data Exchange (ETDEWEB)

Kim, Jin Yong; Choi, Jung-Pyung; Scott Weil, K. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States)

2008-07-15

In this paper, the effects of aluminum on the microstructure, mechanical properties, and high temperature dual atmosphere tolerance of silver and silver-copper oxide filler metals were investigated. It was found that joints brazed with binary Ag-Al braze foils containing more than 2 at% Al retained a metallic form of aluminum within the metallic braze filler matrix after brazing at 1000 C in air. The bend strengths of these joints decreased with increasing aluminum content due to the formation of interfacial aluminum oxide. However, the existence of metallic aluminum in the braze filler matrix appeared to enhance the high-temperature dual atmosphere tolerance of the silver-based braze filler, which displayed measurably less porosity after 1000h of exposure at 800 C in a dual reducing/oxidizing atmosphere environment than unalloyed silver. A series of binary and ternary braze pastes based on the Ag-Al(-Cu) system were also formulated as potential pSOFC (planar solid oxide fuel cell) sealants. Model alumina joints brazed with these pastes exhibited an increase in bend strength with increasing copper content. However, unlike the binary Ag-Al filler metals, the ternary compositions often retained no protective metallic aluminum after brazing. Thus, while the addition of copper improves filler metal wettability and, therefore, joint strength in the Ag-Al alloys, it appears to reduce the dual atmosphere tolerance of these filler metals. (author)

From Large-Scale Synthesis to Lighting Device Applications of Ternary I-III-VI Semiconductor Nanocrystals: Inspiring Greener Material Emitters.

Science.gov (United States)

Chen, Bingkun; Pradhan, Narayan; Zhong, Haizheng

2018-01-18

Quantum dots with fabulous size-dependent and color-tunable emissions remained as one of the most exciting inventories in nanomaterials for the last 3 decades. Even though a large number of such dot nanocrystals were developed, CdSe still remained as unbeatable and highly trusted lighting nanocrystals. Beyond these, the ternary I-III-VI family of nanocrystals emerged as the most widely accepted greener materials with efficient emissions tunable in visible as well as NIR spectral windows. These bring the high possibility of their implementation as lighting materials acceptable to the community and also to the environment. Keeping these in mind, in this Perspective, the latest developments of ternary I-III-VI nanocrystals from their large-scale synthesis to device applications are presented. Incorporating ZnS, tuning the composition, mixing with other nanocrystals, and doping with Mn ions, light-emitting devices of single color as well as for generating white light emissions are also discussed. In addition, the future prospects of these materials in lighting applications are also proposed.

Selective recovery of Ag(I) coordination anion from simulate nickel electrolyte using corn stalk based adsorbent modified by ammonia–thiosemicarbazide

Energy Technology Data Exchange (ETDEWEB)

Xiong, Ying, E-mail: xiongying_1977@hotmail.com; Wan, Li; Xuan, Jing; Wang, Yongwei; Xing, Zhiqing; Shan, Weijun; Lou, Zhenning

2016-01-15

Highlights: • We developed a “green” corn stalk adsorbent treated by thiosemicarbazide–glutaraldehyde. • Adsorption mechanism of AgCl{sub i}{sup 1−i} could be electrostatic interaction with C−SH{sup +}−N and C=SH{sup +} group. • The gel could selectively adsorb AgCl{sub i}{sup 1−i} coordination anion from the Ag(I)–Cu(II)–Ni(II) simulate nickel electrolyte. - Abstract: In nickel electrolyte, Ag(I) was present at trace level concentration (10–20 mg L{sup −1}) and existed in the form of AgCl{sub i}{sup 1−i} coordination anion, instead of Ag{sup +} positive ion usually in several sources. In the present study, TSC-NH{sub 3}-OCS adsorbent based on natural corn stalk modified by ammonia (NH{sub 3})–thiosemicarbazide (TSC) was synthesized and characterized using some instrumental techniques. The TSC-NH{sub 3}-OCS adsorbent could selectively adsorb Ag(I) as AgCl{sub i}{sup 1−i} coordination anion from the Ag(I)–Cu(II)–Ni(II) simulate nickel electrolyte, especially in the case of the very high levels of Cu(II) and Ni(II), which significantly outperforms the commercial available resins. The adsorption mechanism was believed to be electrostatic interaction of the protonated bands of AgCl{sub 4}{sup 3−} with protonated thiol form of the thioamide units by FTIR and XPS analysis. The maximum adsorption capacity in the Ag(I) single and Ag(I)–Cu(II)–Ni(II) ternary system were obtained and calculated as 153.54 and 46.69 mg g{sup −1}, respectively. The reasons that the maximum adsorption capacity of AgCl{sub i}{sup 1−i} from the single and ternary system varied widely could be explained by adsorption kinetic and thermodynamic results. In addition, three successive sorption/desorption cycle runs from ternary system were performed which indicated that the TSC-NH{sub 3}-OCS adsorbent has a good performance for recovery Ag(I) from simulate nickel electrolyte.

Synthesis and Characterization of the Rubidium Thiophosphate Rb 6 (PS 5 )(P 2 S 10 ) and the Rubidium Silver Thiophosphates Rb 2 AgPS 4 , RbAg 5 (PS 4 ) 2 and Rb 3 Ag 9 (PS 4 ) 4

KAUST Repository

Alahmary, Fatimah S.

2016-02-18

The metal thiophosphates Rb2AgPS4 (2), RbAg5(PS4)2 (3), and Rb3Ag9(PS4)4 (4) were synthesized by stoichiometric reactions, whereas Rb6(PS5)(P2S10) (1) was prepared with excess amount of sulfur. The compounds crystallize as follows: 1 monoclinic, P21/c (no. 14), a = 17.0123(7) Å, b = 6.9102(2) Å, c = 23.179(1) Å, β = 94.399(4)°; 2 triclinic, P ¯ (no. 2), a = 6.600(1) Å, b = 6.856(1) Å, c = 10.943(3) Å, α = 95.150(2)°, β = 107.338(2)°, γ = 111.383(2)°; 3 orthorhombic, Pbca (no. 61), a = 12.607(1) Å, b = 12.612(1) Å, c = 17.759(2) Å; 4 orthorhombic, Pbcm (no. 57), a = 6.3481(2) Å, b = 12.5782(4) Å, c = 35.975(1) Å. The crystal structures contain discrete units, chains, and 3D polyanionic frameworks composed of PS4 tetrahedral units arranged and connected in different manner. Compounds 1-3 melt congruently, whereas incongruent melting behavior was observed for compound 4. 1-4 are semiconductors with bandgaps between 2.3 and 2.6 eV and thermally stable up to 450 °C in an inert atmosphere. Copyright © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis and characterization of Zn(O,OH)S and AgInS2 layers to be used in thin film solar cells

Science.gov (United States)

Vallejo, W.; Arredondo, C. A.; Gordillo, G.

2010-11-01

In this paper AgInS2 and Zn(O,OH)S thin films were synthesized and characterized. AgInS2 layers were grown by co-evaporation from metal precursors in a two-step process, and, Zn(O,OH)S thin films were deposited from chemical bath containing thiourea, zinc acetate, sodium citrate and ammonia. X-ray diffraction measurements indicated that AgInS2 thin films grown with chalcopyrite structure, and the as-grown Zn(O,OH)S thin films were polycrystalline. It was also found that the AgInS2 films presented p-type conductivity, a high absorption coefficient (greater than 104 cm-1) and energy band-gap Eg of about 1.95 eV, Zn(O,OH),S thin films presented Eg of about 3.89 eV. Morphological analysis showed that under this synthesis conditions Zn(O,OH),S thin films coated uniformly the absorber layer. Additionally, the Zn(O,OH)S kinetic growth on AgInS2 layer was studied also. Finally, the results suggest that these layers possibly could be used in one-junction solar cells and/or as top cell in a tandem solar cell.

Structural and dielectric studies on Ag doped nano ZnSnO3

Science.gov (United States)

Deepa, K.; Angel, S. Lilly; Rajamanickam, N.; Jayakumar, K.; Ramachandran, K.

2018-04-01

Undoped and Ag-doped nano Zinc Stannate (ZSO) ternary oxide were prepared by co-precipitation method. The crystallographic, morphological and optical properties of the synthesized nanoparticles were studied using X-ray diffraction (XRD) and UV-Visible spectroscopy (UV-Vis) and Scanning electron microscopy (SEM). The electrical properties of the synthesized samples were studied by dielectric measurements. Higher concentration Ag doped ZSO nanoparticles exhibit higher dielectric constant at low frequency.

New chalcogenide glasses in the CdTe-AgI-As{sub 2}Te{sub 3} system

Energy Technology Data Exchange (ETDEWEB)

Kassem, M. [Univ. Picardie Jules Verne, F-80000 Amiens (France); Le Coq, D., E-mail: david.lecoq@univ-littoral.fr [Univ. Lille Nord de France, F-59000 Lille (France); ULCO, LPCA, EA 4493, F-59140 Dunkerque (France); Boidin, R.; Bychkov, E. [Univ. Lille Nord de France, F-59000 Lille (France); ULCO, LPCA, EA 4493, F-59140 Dunkerque (France)

2012-02-15

Highlights: Black-Right-Pointing-Pointer Determination of the glass-forming region in the pseudo-ternary CdTe-AgI-As{sub 2}Te{sub 3} system. Black-Right-Pointing-Pointer Characterization of macroscopic properties of the new CdTe-AgI-As{sub 2}Te{sub 3} glasses. Black-Right-Pointing-Pointer Characterization of the total conductivity of CdTe-AgI-As{sub 2}Te{sub 3} glasses. Black-Right-Pointing-Pointer Comparison between the selenide and telluride equivalent systems. -- Abstract: Chalcogenide glasses in the pseudo-ternary CdTe-AgI-As{sub 2}Te{sub 3} system were synthesized and the glass-forming range was determined. The maximum content of CdTe in this glass system was found to be equal to 15 mol.%. The macroscopic characterizations of samples have consisted in Differential Scanning Calorimetry, density, and X-ray diffraction measurements. The cadmium telluride addition does not generate any significant change in the glass transition temperature but the resistance of binary AgI-As{sub 2}Te{sub 3} glasses towards crystallisation is estimated to be decreasing on the base of {Delta}T = T{sub x} - T{sub g} parameter. The total electrical conductivity {sigma} was measured by complex impedance spectroscopy. First, the CdTe additions in the (AgI){sub 0.5}(As{sub 2}Te{sub 3}){sub 0.5} host glass, (CdTe){sub x}(AgI){sub 0.5-x/2}(As{sub 2}Te{sub 3}){sub 0.5-x/2} lead to a conductivity decrease at x {<=} 0.05. Then, the behaviour is reversed at 0.05 {<=} x {<=} 0.15. The obtained results are discussed by comparison with the equivalent selenide system.

Fast detoxication of 2-chloro ethyl ethyl sulfide by p-type Ag_2O semiconductor nanoparticle-loaded Al_2O_3-based supports

International Nuclear Information System (INIS)

Ma, Meng-Wei; Kuo, Dong-Hau

2016-01-01

Highlights: • Detoxication of CWA surrogate of 2-chloro ethyl ethyl sulfide is investigated. • A small amount of Ag_2O on Al_2O_3-base support is sufficient to degrade 2-CEES. • Detoxication conversion >82% in 15 min is achieved for >2.5% Ag_2O/Na_2SiO_3/Al_2O_3. • Na_2SiO_3 modified Al_2O_3 to have the valley-like line pattern for depositing Ag_2O. • 2-CEES oxidation is initiated from the dominant electronic holes in p-type Ag_2O. - Abstract: p-type Ag_2O semiconductor nanoparticle-loaded Al_2O_3 or Na_2SiO_3/Al_2O_3 powders used for detoxicating the surrogate of sulfur mustard of 2-chloro ethyl ethyl sulfide (C_2H_5SCH_2CH_2Cl, 2-CEES) were investigated. Different amounts of Ag_2O and Na_2SiO_3 on catalyst supports were evaluated. Gas chromatography with a pulsed flame photometric detector (GC–PFPD) and gas chromatography coupled with a mass spectroscopy (GC–MS) were used to monitor and identify the catalytic reactions, together with reaction products analysis. The GC analyses showed that the decontamination of 2-CEES in isopropanol solvent for 15 min was above 82% efficiency for the 0.5% Na_2SiO_3/Al_2O_3 support deposited with a Ag_2O content above 2.5%. 2-(ethylthio)ethanol and 2-(ethylthio)ethanoic acid were identified as the major products after catalytic reactions. The electronic holes dominating in p-type Ag_2O is proposed to provide the key component and to initiate the catalytic reactions. The electronic hole-based detoxication mechanism is proposed.

Intermixing, band alignment and charge transport in AgIn5S8/CuI heterojunctions

International Nuclear Information System (INIS)

Konovalov, I.; Makhova, L.; Hesse, R.; Szargan, R.

2005-01-01

Possibilities of creating photovoltaic devices using CuI/AgIn 5 S 8 heterojunctions are considered. Among other properties, preferential formation of polar (111) surfaces makes n-type AgIn 5 S 8 an attractive candidate for absorber layers of top cells in 4-terminal tandem structures. Cu-Ag exchange at the interface with p-type CuI was observed. This intermixing results in an additional component of Ag 3d5 photoelectron line after deposition of CuI, in the Cu (but not I) contamination of the surface after a chemical removal of CuI, and in a photoelectric sensitivity of the junction at energies below the band gaps. Valence band offsets of 0.4 and 0.5 eV (cliff) were found at interfaces with thin film and bulk AgIn 5 S 8 , supporting a conduction mechanism through interface recombination. Pinning conflict at the interface between materials with contradictory doping limitations is likely to promote the intermixing

Photodegradation properties and optics of Ag/TiO{sub 2} films; Propiedades de fotodegradacion y opticas de peliculas Ag/TiO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Tirado G, S. [IPN, Escuela Superior de Fisica y Matematicas, San Pedro Zacatenco, 07738 Ciudad de Mexico (Mexico); Valenzuela Z, M. A., E-mail: tirado@esfm.ipn.mx [IPN, Escuela Superior de Ingenieria Quimica e Industrias Extractivas, Laboratorio de Catalisis y Materiales, San Pedro Zacatenco, 07738 Ciudad de Mexico (Mexico)

2016-10-15

In the thin semiconductor films of Ag/TiO{sub 2} the topographic properties were recorded by atomic force microscopy and the main parameters of roughness were determined; the optical properties were also recorded when determining their transmittance degree, their refractive indexes, their thickness and the bandwidth of the semiconductor Eg, both for pure TiO{sub 2} films and the modified Ag/TiO{sub 2} films with various layers of the Ag catalyst. The Ag/TiO{sub 2} films that were grown by sol-gel and repeated immersion, chemical technique that has been used in the development of thin film technology, were carried out in photo catalysis, when are used in photo degradation of methyl orange at an aqueous concentration of 14 ppm, once they are characterized with several techniques required to be able to explain the possible photo catalytic reactions at the solid-aqueous interface, when irradiated with UV; with the possible application in water treatment. The photoluminescence spectra of the prepared Ag/TiO{sub 2} samples are reported, which resulted in a green emission, characteristic of the visible, in addition to emissions in the UV range. (Author)

Recent Developments in p-Type Oxide Semiconductor Materials and Devices

KAUST Repository

Wang, Zhenwei

2016-02-16

The development of transparent p-type oxide semiconductors with good performance may be a true enabler for a variety of applications where transparency, power efficiency, and greater circuit complexity are needed. Such applications include transparent electronics, displays, sensors, photovoltaics, memristors, and electrochromics. Hence, here, recent developments in materials and devices based on p-type oxide semiconductors are reviewed, including ternary Cu-bearing oxides, binary copper oxides, tin monoxide, spinel oxides, and nickel oxides. The crystal and electronic structures of these materials are discussed, along with approaches to enhance valence-band dispersion to reduce effective mass and increase mobility. Strategies to reduce interfacial defects, off-state current, and material instability are suggested. Furthermore, it is shown that promising progress has been made in the performance of various types of devices based on p-type oxides. Several innovative approaches exist to fabricate transparent complementary metal oxide semiconductor (CMOS) devices, including novel device fabrication schemes and utilization of surface chemistry effects, resulting in good inverter gains. However, despite recent developments, p-type oxides still lag in performance behind their n-type counterparts, which have entered volume production in the display market. Recent successes along with the hurdles that stand in the way of commercial success of p-type oxide semiconductors are presented.

Recent Developments in p-Type Oxide Semiconductor Materials and Devices

KAUST Repository

Wang, Zhenwei; Nayak, Pradipta K.; Caraveo-Frescas, Jesus Alfonso; Alshareef, Husam N.

2016-01-01

The development of transparent p-type oxide semiconductors with good performance may be a true enabler for a variety of applications where transparency, power efficiency, and greater circuit complexity are needed. Such applications include transparent electronics, displays, sensors, photovoltaics, memristors, and electrochromics. Hence, here, recent developments in materials and devices based on p-type oxide semiconductors are reviewed, including ternary Cu-bearing oxides, binary copper oxides, tin monoxide, spinel oxides, and nickel oxides. The crystal and electronic structures of these materials are discussed, along with approaches to enhance valence-band dispersion to reduce effective mass and increase mobility. Strategies to reduce interfacial defects, off-state current, and material instability are suggested. Furthermore, it is shown that promising progress has been made in the performance of various types of devices based on p-type oxides. Several innovative approaches exist to fabricate transparent complementary metal oxide semiconductor (CMOS) devices, including novel device fabrication schemes and utilization of surface chemistry effects, resulting in good inverter gains. However, despite recent developments, p-type oxides still lag in performance behind their n-type counterparts, which have entered volume production in the display market. Recent successes along with the hurdles that stand in the way of commercial success of p-type oxide semiconductors are presented.

Double Z-scheme ZnO/ZnS/g-C3N4 ternary structure for efficient photocatalytic H2 production

Science.gov (United States)

Dong, Zhifang; Wu, Yan; Thirugnanam, Natarajan; Li, Gonglin

2018-02-01

In the present work, a novel ZnO/ZnS/g-C3N4 ternary nanocomposite with double Z-scheme heterojunction has been designed via a two-step facile chemical conversion route. The spherical ZnS nanoparticles were uniformly loaded onto ZnO nanoflowers surface. And then the ZnO/ZnS nanocomposite was further hybridized with g-C3N4 nanosheets. Ternary ZnO/ZnS/g-C3N4 nanocomposite displays the largest specific surface area (about 76.2 m2/g), which provides plentiful activated sites for photocatalytic reaction. Furthermore, the ternary material exhibits the highest methylene blue photodegradation rate of about 0.0218 min-1 and the optimum photocatalytic H2 production (1205 μmol/g) over water splitting at 4 h under solar light irradiation. Moreover, it showed the highest photocurrent effect and the minimum charge-transfer resistance. These results implied that the higher photoactivity of ZnO/ZnS/g-C3N4 nanocomposite could be attributed to the multi-steps charge transfer and effective electron-hole separation in the double Z-scheme system.

Compound Semiconductor Radiation Detector

International Nuclear Information System (INIS)

Kim, Y. K.; Park, S. H.; Lee, W. G.; Ha, J. H.

2005-01-01

In 1945, Van Heerden measured α, β and γ radiations with the cooled AgCl crystal. It was the first radiation measurement using the compound semiconductor detector. Since then the compound semiconductor has been extensively studied as radiation detector. Generally the radiation detector can be divided into the gas detector, the scintillator and the semiconductor detector. The semiconductor detector has good points comparing to other radiation detectors. Since the density of the semiconductor detector is higher than that of the gas detector, the semiconductor detector can be made with the compact size to measure the high energy radiation. In the scintillator, the radiation is measured with the two-step process. That is, the radiation is converted into the photons, which are changed into electrons by a photo-detector, inside the scintillator. However in the semiconductor radiation detector, the radiation is measured only with the one-step process. The electron-hole pairs are generated from the radiation interaction inside the semiconductor detector, and these electrons and charged ions are directly collected to get the signal. The energy resolution of the semiconductor detector is generally better than that of the scintillator. At present, the commonly used semiconductors as the radiation detector are Si and Ge. However, these semiconductor detectors have weak points. That is, one needs thick material to measure the high energy radiation because of the relatively low atomic number of the composite material. In Ge case, the dark current of the detector is large at room temperature because of the small band-gap energy. Recently the compound semiconductor detectors have been extensively studied to overcome these problems. In this paper, we will briefly summarize the recent research topics about the compound semiconductor detector. We will introduce the research activities of our group, too

Designing and Validating Ternary Pd Alloys for Optimum Sulfur/Carbon Resistance in Hydrogen Separation and Carbon Capture Membrane Systems Using High-Throughput Combinatorial Methods

Energy Technology Data Exchange (ETDEWEB)

Lewis, Amanda [Pall Corporation, Port Washington, NY (United States); Zhao, Hongbin [Pall Corporation, Port Washington, NY (United States); Hopkins, Scott [Pall Corporation, Port Washington, NY (United States)

2014-12-01

This report summarizes the work completed under the U.S. Department of Energy Project Award No.: DE-FE0001181 titled “Designing and Validating Ternary Pd Alloys for Optimum Sulfur/Carbon Resistance in Hydrogen Separation and Carbon Capture Membrane Systems Using High-Throughput Combinatorial Methods.” The project started in October 1, 2009 and was finished September 30, 2014. Pall Corporation worked with Cornell University to sputter and test palladium-based ternary alloys onto silicon wafers to examine many alloys at once. With the specialized equipment at Georgia Institute of Technology that analyzed the wafers for adsorbed carbon and sulfur species six compositions were identified to have resistance to carbon and sulfur species. These compositions were deposited on Pall AccuSep® supports by Colorado School of Mines and then tested in simulated synthetic coal gas at the Pall Corporation. Two of the six alloys were chosen for further investigations based on their performance. Alloy reproducibility and long-term testing of PdAuAg and PdZrAu provided insight to the ability to manufacture these compositions for testing. PdAuAg is the most promising alloy found in this work based on the fabrication reproducibility and resistance to carbon and sulfur. Although PdZrAu had great initial resistance to carbon and sulfur species, the alloy composition has a very narrow range that hindered testing reproducibility.

NaAuS chicken-wire-like semiconductor: Electronic structure and optical properties

International Nuclear Information System (INIS)

Reshak, A.H.; Khan, Saleem Ayaz; Kamarudin, H.; Bila, Jiri

2014-01-01

Highlights: • Chicken wire like semiconductor NaAuS was investigated. • Good agreement with experimental data was found. • Electronic charge density of chicken wire like semiconductor NaAuS was obtained. • The calculated uniaxial anisotropy is −0.0005, indicating the strong anisotropy. -- Abstract: The electronic structure, charge density and optical properties of NaAuS a chicken-wire-like semiconductor was calculated using full potential linear augmented plane wave based on density functional theory. The Ceperley-Alder local density approximation, Perdew Becke Ernzerhof Generalized gradient approximation and Engel Voskov Generalized Gradient Approximation were applied to solve the exchange correlation potential. The investigation of band structures and density of states elucidates that Engle Vasko Generalized Gradient Approximation shows close agreement to the experimental data. The calculated valence charge density shows pure ionic nature of Au–Au bond. It becomes partially covalent when Au is connected with two Na atoms. The linear optical susceptibilities of chicken-wire-like NaAuS semiconductor are calculated so as to obtain further insight into the electronic properties. The uniaxial anisotropy is −0.0005, indicating the strong anisotropy of the dielectric function in the NaAuS a chicken-wire-like semiconductor

NaAuS chicken-wire-like semiconductor: Electronic structure and optical properties

Energy Technology Data Exchange (ETDEWEB)

Reshak, A.H. [Institute of Complex Systems, FFPW, CENAKVA, University of South Bohemia in CB, Nove Hrady 37333 (Czech Republic); Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia); Khan, Saleem Ayaz, E-mail: sayaz_usb@yahoo.com [Institute of Complex Systems, FFPW, CENAKVA, University of South Bohemia in CB, Nove Hrady 37333 (Czech Republic); Kamarudin, H. [Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia); Bila, Jiri [Department of Instrumentation and Control Engineering, Faculty of Mechanical Engineering, CTU in Prague, Technicka 4, 166 07 Prague 6 (Czech Republic)

2014-01-05

Highlights: • Chicken wire like semiconductor NaAuS was investigated. • Good agreement with experimental data was found. • Electronic charge density of chicken wire like semiconductor NaAuS was obtained. • The calculated uniaxial anisotropy is −0.0005, indicating the strong anisotropy. -- Abstract: The electronic structure, charge density and optical properties of NaAuS a chicken-wire-like semiconductor was calculated using full potential linear augmented plane wave based on density functional theory. The Ceperley-Alder local density approximation, Perdew Becke Ernzerhof Generalized gradient approximation and Engel Voskov Generalized Gradient Approximation were applied to solve the exchange correlation potential. The investigation of band structures and density of states elucidates that Engle Vasko Generalized Gradient Approximation shows close agreement to the experimental data. The calculated valence charge density shows pure ionic nature of Au–Au bond. It becomes partially covalent when Au is connected with two Na atoms. The linear optical susceptibilities of chicken-wire-like NaAuS semiconductor are calculated so as to obtain further insight into the electronic properties. The uniaxial anisotropy is −0.0005, indicating the strong anisotropy of the dielectric function in the NaAuS a chicken-wire-like semiconductor.

Investigation of AgInS2 thin films grown by coevaporation

Science.gov (United States)

Arredondo, C. A.; Clavijo, J.; Gordillo, G.

2009-05-01

AgInS2 thin films were grown on soda-lime glass substrates by co-evaporation of the precursors in a two-step process. X-ray diffraction (XRD) measurements indicated that these compounds grow in different phases and with different crystalline structure depending upon the deposition conditions. However, through a parameter study, conditions were found to grow thin films containing only the AgInS2 phase with chalcopyrite type structure. In samples containing a mixture of several phases, the contribution in percentage terms of each phase to the whole compound was estimated with the help of the PowderCell simulation package. It was also found that the AgInS2 films present p-type conductivity, a high absorption coefficient (greater than 104 cm-1) and an energy band gap Eg of about 1.95 eV, indicating that this compound has good properties to perform as absorbent layer in thin film tandem solar cells. The effect of the deposition conditions on the optical and morphological properties was also investigated through spectral transmitance and atomic force microscopy (AFM) measurements.

Photovoltaic applications of Cu(Sb,Bi)SM (M = Ag, Pb, Pt)

Science.gov (United States)

Tablero, C.

2017-04-01

Ternary Cu-(Sb,Bi)-S compounds are great absorbents of the solar radiation with a variety of applications including optoelectronic and photovoltaic applications. The analyses of several quaternary semiconductors derived from Cu-(Sb,Bi)-S materials is carried out using first-principles density-functional theory with orbital-dependent one-electron potentials. These analyses focus on the optoelectronic properties and the potential for solar cells. The optical properties are obtained from first-principles calculations, and split into inter- and intra-shell-species contributions in order to quantify the optical transitions responsible for the absorption. The absorption coefficients are then used as criteria to evaluate the efficiencies of these materials under several sunlight concentrations. The results indicate high energy photovoltaic conversion efficiency because of the large intra shell s-p absorption of the S and Sb or Bi atomic species.

Thermodynamic behavior of very stable binary compounds with a wide homogeneity range: Their influence in the liquid phase in ternary and higher component systems in the solid state

International Nuclear Information System (INIS)

Hoch, M.

1988-01-01

The Hoch-Arpshofen model is combined with the Schottky-Wagner disorder model to describe first binary liquid systems, where a very stable solid protrudes into the liquid. We analyze the systems K-I 2 , Cs-I 2 , U-UO 3 , Ag-S and Al-Sb. The system Al-Sb can be described as Al-Sb and as Al-AlSb-Sb. Then we examine the Al-Co, Al-Ni, and Al-Fe systems to describe the stable compounds CoAl, NiAl, and FeAl, which all have a wide homogeneity range in the solid state. Here the Schottky-Wagner model is sufficient. Finally we describe a model which treats the influence of these stable binary compounds in ternary and larger systems such as Al-Cr-Ni and Al-Cr-Fe, again in the solid state. (orig./IHOE) [de

Electronic structure and optical properties of the scintillation material wurtzite ZnS(Ag)

Institute of Scientific and Technical Information of China (English)

Dong-Yang Jiang; Zheng Zhang; Rui-Xue Liang; Zhi-Hong Zhang; Yang Li; Qiang Zhao; Xiao-Ping Ouyang

2017-01-01

In order to investigate the effect of Ag doping (ZnS(Ag)) and Zn vacancy (Vzn) on the alpha particle detection performance of wurtzite (WZ) ZnS as a scintillation cell component,the electronic structure and optical properties of ZnS,ZnS(Ag),and Vzn were studied by firstprinciple calculation based on the density functional theory.The results show that the band gaps of ZnS,ZnS(Ag),and Vzn are 2.17,1.79,and 2.37 eV,respectively.Both ZnS(Ag) and Vzn enhance the absorption and reflection of the low energy photons.A specific energy,about 2.9 eV,leading to decrease of detection efficiency is observed.The results indicate that Ag doping has a complex effect on the detection performance.It is beneficial to produce more visible light photons than pure WZ ZnS when exposed to the same amount of radiation,while the increase of the absorption to visible light photons weakens the detection performance.Zn vacancy has negative effect on the detection performance.If we want to improve the detection performance of WZ ZnS,Ag doping will be a good way,but we should reduce the absorption to visible light photons and control the number of Zn vacancy rigorously.

Electronic transport behavior of diameter-graded Ag nanowires

International Nuclear Information System (INIS)

Wang Xuewei; Yuan Zhihao

2010-01-01

Ag nanowires with a graded diameter in anodic aluminum oxide (AAO) membranes were fabricated by the direct-current electrodeposition. The Ag nanowires have a graded-change in diameter from 8 to 32 nm, which is matched with the graded-change of the AAO pore diameter. Electronic transport measurements show that there is a transport behavior similar to that of a metal-semiconductor junction along the axial direction in the diameter-graded Ag nanowires. Such a novel homogeneous nanojunction will be of great fundamental and practical significance.

Electronic transport behavior of diameter-graded Ag nanowires

Science.gov (United States)

Wang, Xue Wei; Yuan, Zhi Hao

2010-05-01

Ag nanowires with a graded diameter in anodic aluminum oxide (AAO) membranes were fabricated by the direct-current electrodeposition. The Ag nanowires have a graded-change in diameter from 8 to 32 nm, which is matched with the graded-change of the AAO pore diameter. Electronic transport measurements show that there is a transport behavior similar to that of a metal-semiconductor junction along the axial direction in the diameter-graded Ag nanowires. Such a novel homogeneous nanojunction will be of great fundamental and practical significance.

Luminescent Ag-doped In{sub 2}S{sub 3} nanoparticles stabilized by mercaptoacetate in water and glycerol

Energy Technology Data Exchange (ETDEWEB)

Raevskaya, Alexandra E.; Ivanchenko, Maria V.; Stroyuk, Oleksandr L., E-mail: alstroyuk@ukr.net, E-mail: stroyuk@inphyschem-nas.kiev.ua; Kuchmiy, Stepan Ya. [L.V. Pysarzhevsky Institute of Physical Chemistry of National Academy of Sciences of Ukraine, Department of Photochemistry (Ukraine); Plyusnin, Victor F. [Institute of Chemical Kinetics and Combustion of Siberian Branch of Russian Academy of Sciences (Russian Federation)

2015-03-15

Colloidal nanoparticles (NPs) of tetragonal β-In{sub 2}S{sub 3} were stabilized in water and glycerol by mercaptoacetate anions. Doping of In{sub 2}S{sub 3} NPs with Ag{sup I} cations at the time of the synthesis imparts the NPs with the photoluminescence (PL) in the visible part of the spectrum. The doping results also in a shift of the absorption threshold and the PL band maximum to longer wavelengths proportional to the Ag{sup I} content. The PL band maximum of Ag{sup I}-doped In{sub 2}S{sub 3} NPs can be varied from 575–580 to 760–765 nm by augmenting the silver(I) amount and the duration and temperature of the post-synthesis aging. The average radiative life-time of Ag{sup I}-doped In{sub 2}S{sub 3} NPs also depends on the silver(I) content and reaches the maximal value, 960 ns, at a molar Ag:In ratio of 1:4. The maximal quantum yield of stationary PL, 12 %, is observed at this Ag:In ratio as well. Deposition of a ZnS “shell” on the surface of Ag{sup I}-doped In{sub 2}S{sub 3} NPs results in an increase of the PL quantum yield to ∼30 %.

Experimental and theoretical investigation on photocatalytic activities of 1D Ag/Ag2WO4 nanostructures

Science.gov (United States)

Liu, Danqing; Huang, Weicheng; Li, Long; Liu, Lu; Sun, Xiaojun; Liu, Bo; Yang, Bin; Guo, Chongshen

2017-09-01

Ag2WO4 is a significant photocatalyst that responds to UV light irradiation only, which greatly hinders it for further practical application for solar light. To address this problem, herein, 1D plasmonic Ag/Ag2WO4 photocatalysts have been fabricated by a successive process including hydrothermal synthesis to obtain Ag2WO4 followed by an additional in situ chemical-reduction process for Ag decoration. Then, the structural features, optical properties, and electronic structures of Ag2WO4 and Ag/Ag2WO4 nanowires were systematically investigated via a combination of theoretical calculations and experimental evidence. The plasmon-enhanced Ag/Ag2WO4 nanowires exhibited higher visible-light-driven photocatalytic activity, which performed a desired photodestruction ratio of 91.2% on methylene blue within 60 min and good stability in five cycles. The Ag decoration greatly facilitates visible-light harvesting and thus promotes photogenerated radical oxidation to dye, which is evidenced by the higher hydroxyl radical level of Ag/Ag2WO4 detected in the ESR test during the photocatalytic process. The theoretical calculation based on density functional theory indicates that Ag nanoparticles formed on the surface of Ag2WO4 could narrow the band gap of Ag2WO4. In addition, the surface plasmon resonance absorption effect and fast charge transfer effect in the metal-semiconductor system contribute to the photocatalytic performance of Ag/Ag2WO4.

Nuclear Electrical and Optical Studies of Hydrogen in Semiconductors.

CERN Multimedia

Dietrich, M; Toulemonde, M

2002-01-01

During the last years, the understanding of H and its interaction with dopant atoms in Si, Ge and III-V semiconductors has improved considerably concerning the stability of the formed complexes their structural arrangements, and the implications of this interaction on the electrical properties of the semiconductors " passivation " The perturbed angular correlation technique (PAC) has contributed to the understanding of this phenomena on an atomistic scale using radioactive isotopes provided by ISOLDE. \\\\ \\\\The aim of the proposed experiments is twofold: \\\\ \\\\\\begin{enumerate} \\item The H passivation mechanism of acceptors in GaN and ternary III-V compounds (AlGaAs, GaInP, AlGaN) shall be investigated, using the PAC probe atom $^{111m}$Cd as a 'representative' of group II-B metal acceptors. The problems addressed in these technological important systems are microscopic structure, formation and stability of the hydrogen correlated complexes as function of doping and stoichiometry (i.e. the size of the band gap)...

Optical power limiting in ensembles of colloidal Ag{sub 2}S quantum dots

Energy Technology Data Exchange (ETDEWEB)

Ovchinnikov, O V; Smirnov, M S; Perepelitsa, A S; Shatskikh, T S [Voronezh State University, Voronezh (Russian Federation); Shapiro, B I [M.V. Lomonosov Moscow State Academy of Fine Chemical Technology, Moscow (Russian Federation)

2015-12-31

The effect of power limiting for optical radiation at a wavelength of 660 nm with a pulse duration of 10 ms and operation threshold of 2.2 – 3.1 mJ cm{sup -2} is observed in ensembles of colloidal Ag{sub 2}S quantum dots (QDs). Using the z-scanning method in an open-aperture scheme it is found that the power is limited mainly due to reverse saturable absorption caused by two-photon optical transitions that involve energy levels of Ag{sub 2}S photoluminescence centres, related to structural impurity defects in colloidal Ag{sub 2}S QDs. At the same time, the z-scanning in a closed-aperture scheme demonstrates the formation of a thermal dynamic lens. (nonlinear optical phenomena)

Susceptibility of ternary aluminum alloys to cracking during solidification

International Nuclear Information System (INIS)

Liu, Jiangwei; Kou, Sindo

2017-01-01

The crack susceptibility map of a ternary Al alloy system provides useful information about which alloy compositions are most susceptible to cracking and thus should be avoided by using a filler metal with a significantly different composition. In the present study the crack susceptibility maps of ternary Al alloy systems were calculated based on the maximum |dT/d(f S ) 1/2 | as an index for the crack susceptibility, where T is temperature and f S fraction solid. Due to the complexity associated with ternary alloy solidification, commercial thermodynamic software Pandat and Al database PanAluminum, instead of analytical equations, were used to calculate f S as a function of T and hence the maximum |dT/d(f S ) 1/2 | for ternary Al-Mg-Si, Al-Cu-Mg and Al-Cu-Si alloy systems. A crack susceptibility map covering 121 alloy compositions was constructed for each of the three ternary alloy systems at each of the following three levels of back diffusion: no back diffusion, back diffusion under a 100 °C/s cooling rate, and back diffusion under 20° C/s. The location of the region of high crack susceptibility, which is the most important part of the map, was shown in each of the nine calculated maps. These locations were compared with those observed in crack susceptibility tests by previous investigators. With back diffusion considered, either under 20 or 100 °C/s, the agreement between the calculated and observed maps was good especially for Al-Mg-Si and Al-Cu-Mg. Thus, the maximum |dT/d(f S ) 1/2 | can be used as a crack susceptibility index to construct crack susceptibility maps for ternary Al alloys and to evaluate the effect of back diffusion on their crack susceptibility. - Graphical abstract: The crack susceptibility map of a ternary alloy system indicates the composition range most susceptible to cracking, which should be avoided in welding or casting. The crack susceptibility maps of ternary Al alloy systems Al-Mg-Si, Al-Cu-Mg and Al-Cu-Si were calculated based

Photodegradation properties and optics of Ag/TiO2 films

International Nuclear Information System (INIS)

Tirado G, S.; Valenzuela Z, M. A.

2016-10-01

In the thin semiconductor films of Ag/TiO 2 the topographic properties were recorded by atomic force microscopy and the main parameters of roughness were determined; the optical properties were also recorded when determining their transmittance degree, their refractive indexes, their thickness and the bandwidth of the semiconductor Eg, both for pure TiO 2 films and the modified Ag/TiO 2 films with various layers of the Ag catalyst. The Ag/TiO 2 films that were grown by sol-gel and repeated immersion, chemical technique that has been used in the development of thin film technology, were carried out in photo catalysis, when are used in photo degradation of methyl orange at an aqueous concentration of 14 ppm, once they are characterized with several techniques required to be able to explain the possible photo catalytic reactions at the solid-aqueous interface, when irradiated with UV; with the possible application in water treatment. The photoluminescence spectra of the prepared Ag/TiO 2 samples are reported, which resulted in a green emission, characteristic of the visible, in addition to emissions in the UV range. (Author)

Synthesis and properties of new CdSe-AgI-As2Se3 chalcogenide glasses

International Nuclear Information System (INIS)

Kassem, M.; Le Coq, D.; Fourmentin, M.; Hindle, F.; Bokova, M.; Cuisset, A.; Masselin, P.; Bychkov, E.

2011-01-01

Research highlights: → Determination of the glass-forming region in the pseudo-ternary CdSe-AgI-As 2 Se 3 system. → Characterization of macroscopic properties of the new CdSe-AgI-As 2 Se 3 glasses. → Far infrared transmission of chalcogenide glasses. → Characterization of the total conductivity of CdSe-AgI-As 2 Se 3 glasses. -- Abstract: The glass-forming region in the pseudo-ternary CdSe-AgI-As 2 Se 3 system was determined. Measurements including differential scanning calorimetry (DSC), density, and X-ray diffraction were performed. The effect resulting from the addition of CdSe or AgI has been highlighted by examining three series of different base glasses. The characteristic temperatures of the glass samples, including glass transition (T g ), crystallisation (T x ), and melting (T m ) temperatures are reported and used to calculate their ΔT = T x - T g and their Hruby, H r = (T x - T g )/(T m - T x ), criteria. Evolution of the total electrical conductivity σ and the room temperature conductivity σ 298 was also studied. The terahertz transparency domain in the 50-600 cm -1 region was pointed for different chalcogenide glasses (ChGs) and the potential of the THz spectroscopy was suggested to obtain structural information on ChGs.

Controllable Charge Transfer in Ag-TiO2 Composite Structure for SERS Application

Directory of Open Access Journals (Sweden)

Yaxin Wang

2017-06-01

Full Text Available The nanocaps array of TiO2/Ag bilayer with different Ag thicknesses and co-sputtering TiO2-Ag monolayer with different TiO2 contents were fabricated on a two-dimensional colloidal array substrate for the investigation of Surface enhanced Raman scattering (SERS properties. For the TiO2/Ag bilayer, when the Ag thickness increased, SERS intensity decreased. Meanwhile, a significant enhancement was observed when the sublayer Ag was 10 nm compared to the pure Ag monolayer, which was ascribed to the metal-semiconductor synergistic effect that electromagnetic mechanism (EM provided by roughness surface and charge-transfer (CT enhancement mechanism from TiO2-Ag composite components. In comparison to the TiO2/Ag bilayer, the co-sputtered TiO2-Ag monolayer decreased the aggregation of Ag particles and led to the formation of small Ag particles, which showed that TiO2 could effectively inhibit the aggregation and growth of Ag nanoparticles.

Direct evidence of strong local ferroelectric ordering in a thermoelectric semiconductor

Energy Technology Data Exchange (ETDEWEB)

Aggarwal, Leena; Sekhon, Jagmeet S.; Arora, Ashima; Sheet, Goutam, E-mail: goutam@iisermohali.ac.in [Department of Physical Sciences, Indian Institute of Science Education and Research Mohali (IISER M), Sector 81, S. A. S. Nagar, Manauli PO-140306 (India); Guin, Satya N.; Negi, Devendra S.; Datta, Ranjan; Biswas, Kanishka, E-mail: kanishka@jncasr.ac.in [New Chemistry Unit and International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur, Bangalore 560064 (India)

2014-09-15

It is thought that the proposed new family of multi-functional materials, namely, the ferroelectric thermoelectrics may exhibit enhanced functionalities due to the coupling of the thermoelectric parameters with ferroelectric polarization in solids. Therefore, the ferroelectric thermoelectrics are expected to be of immense technological and fundamental significance. As a first step towards this direction, it is most important to identify the existing high performance thermoelectric materials exhibiting ferroelectricity. Herein, through the direct measurement of local polarization switching, we show that the recently discovered thermoelectric semiconductor AgSbSe{sub 2} has local ferroelectric ordering. Using piezo-response force microscopy, we demonstrate the existence of nanometer scale ferroelectric domains that can be switched by external electric field. These observations are intriguing as AgSbSe{sub 2} crystalizes in cubic rock-salt structure with centro-symmetric space group (Fm–3m), and therefore, no ferroelectricity is expected. However, from high resolution transmission electron microscopy measurement, we found the evidence of local superstructure formation which, we believe, leads to local distortion of the centro-symmetric arrangement in AgSbSe{sub 2} and gives rise to the observed ferroelectricity. Stereochemically active 5S{sup 2} lone-pair of Sb may also give rise to local structural distortion thereby creating ferroelectricity in AgSbSe{sub 2}.

Determination of the transport levels in thin films of organic semiconductors

Energy Technology Data Exchange (ETDEWEB)

Krause, Stefan

2009-07-27

The approach of using the combination of Ultraviolet (UPS) and Inverse Photoemission (IPS) to determine the transport levels in thin films of organic semiconductors is the scope of this work. For this matter all influences on the peak position and width in Photoelectron Spectroscopy are discussed with a special focus on organic semiconductors. Many of these influences are shown with experimental results of the investigation of diindenoperylene on Ag(111). These findings are applied to inorganic semiconductors silicon in order to establish the use of UPS and IPS on a well-understood system. Finally, the method is used to determine the transport level of several organic semiconductors (PTCDA, Alq3, CuPc, DIP, PBI-H4) and the corresponding exciton binding energies are calculated by comparison to optical absorption data. (orig.)

TlHgInS ₃ : An Indirect-Band-Gap Semiconductor with X-ray Photoconductivity Response

Energy Technology Data Exchange (ETDEWEB)

Li, Hao; Malliakas, Christos D.; Han, Fei; Chung, Duck Young; Kanatzidis, Mercouri G.

2015-08-11

The quaternary compound TlHgInS3 crystallizes in a new structure type of space group, C2/c, with cell parameters a = 13.916(3) angstrom, b = 3.9132(8) angstrom, c = 21.403(4) angstrom, beta = 104.16(3)degrees, V = 1130.1(8) angstrom(3), and rho = 7.241 g/cm(3). The structure is a unique three-dimensional framework with parallel tunnels, which is formed by (1)(infinity)[InS33-] infinite chains bridged by linearly coordinated Hg2+ ions. TlHgInS3 is a semiconductor with a band gap of 1.74 eV and a resistivity of similar to 4.32 G Omega cm. TlHgInS3 single crystals exhibit photocurrent response when exposed to Ag X-rays. The mobility-lifetime product (mu tau) of the electrons and holes estimated from the photocurrent measurements are (mu tau)(e) approximate to 3.6 x 10(-4) cm(2)/V and (mu tau)(h) approximate to 2.0 x 10(-4) cm(2)/V. Electronic structure calculations at the density functional theory level indicate an indirect band gap and a relatively small effective mass for both electrons and holes. Based on the photoconductivity data, TlHgInS3 is a potential material for radiation detection applications.

Syntheses and crystal structures of BaAgTbS{sub 3}, BaCuGdTe{sub 3}, BaCuTbTe{sub 3}, BaAgTbTe{sub 3}, and CsAgUTe{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Prakash, Jai; Beard, Jessica C.; Ibers, James A. [Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113 (United States); Mesbah, Adel [Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113 (United States); ICSM-UMR 5257 CNRS/CEA/UM2/ENSCM, Bat 426, BP 17171, 30207 Bagnols/Ceze (France)

2015-06-15

Five new quaternary chalcogenides of the 1113 family, namely BaAgTbS{sub 3}, BaCuGdTe{sub 3}, BaCuTbTe{sub 3}, BaAgTbTe{sub 3}, and CsAgUTe{sub 3}, were synthesized by the reactions of the elements at 1173-1273 K. For CsAgUTe{sub 3} CsCl flux was used. Their crystal structures were determined by single-crystal X-ray diffraction studies. The sulfide BaAgTbS{sub 3} crystallizes in the BaAgErS{sub 3} structure type in the monoclinic space group C{sup 3},{sub 2h}-C2/m, whereas the tellurides BaCuGdTe{sub 3}, BaCuTbTe{sub 3}, BaAgTbTe{sub 3}, and CsAgUTe{sub 3} crystallize in the KCuZrS{sub 3} structure type in the orthorhombic space group D{sup 1},{sub 2}{sup 7},{sub h}-Cmcm. The BaAgTbS{sub 3} structure consists of edge-sharing [TbS{sub 6}{sup 9-}] octahedra and [AgS{sub 5}{sup 9-}] trigonal pyramids. The connectivity of these polyhedra creates channels that are occupied by Ba atoms. The telluride structure features {sup 2}{sub ∞}[MLnTe{sub 3}{sup 2-}] layers for BaCuGdTe{sub 3}, BaCuTbTe{sub 3}, BaAgTbTe{sub 3}, and {sup 2}{sub ∞}[AgUTe{sub 3}{sup 1-}] layers for CsAgUTe{sub 3}. These layers comprise [MTe{sub 4}] tetrahedra and [LnTe{sub 6}] or [UTe{sub 6}] octahedra. Ba or Cs atoms separate these layers. As there are no short Q..Q (Q = S or Te) interactions these compounds achieve charge balance as Ba{sup 2+}M{sup +}Ln{sup 3+}(Q{sup 2-}){sub 3} (Q = S and Te) and Cs{sup +}Ag{sup +}U{sup 4+}(Te{sup 2-}){sub 3}. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Broadband absorption and enhanced photothermal conversion property of octopod-like Ag@Ag2S core@shell structures with gradually varying shell thickness.

Science.gov (United States)

Jiang, Qian; Zeng, Wenxia; Zhang, Canying; Meng, Zhaoguo; Wu, Jiawei; Zhu, Qunzhi; Wu, Daxiong; Zhu, Haitao

2017-12-19

Photothermal conversion materials have promising applications in many fields and therefore they have attracted tremendous attention. However, the multi-functionalization of a single nanostructure to meet the requirements of multiple photothermal applications is still a challenge. The difficulty is that most nanostructures have specific absoprtion band and are not flexible to different demands. In the current work, we reported the synthesis and multi-band photothermal conversion of Ag@Ag 2 S core@shell structures with gradually varying shell thickness. We synthesized the core@shell structures through the sulfidation of Ag nanocubes by taking the advantage of their spatially different reactivity. The resulting core@shell structures show an octopod-like mopgorlogy with a Ag 2 S bulge sitting at each corner of the Ag nanocubes. The thickness of the Ag 2 S shell gradually increases from the central surface towards the corners of the structure. The synthesized core@shell structures show a broad band absorption spectrum from 300 to 1100 nm. Enhanced photothermal conversion effect is observed under the illuminations of 635, 808, and 1064 nm lasers. The results indicate that the octopod-like Ag@Ag 2 S core@shell structures have characteristics of multi-band photothermal conversion. The current work might provide a guidance for the design and synthesis of multifunctional photothermal conversion materials.

Surface assisted electric transport in Ag2S thin films

International Nuclear Information System (INIS)

Karashanova, D.; Starbov, N.

2006-01-01

Electric transport measurements of thickness-dependent electronic and ionic conductivity of epitaxial Ag 2 S films are used to split both kinds of conductivity into bulk and surface components. The established considerable electronic and ionic surface conductances demonstrate unambiguously the co-existance of electronic and ionic space charge regions in the vicinity of silver sulfide free surface oriented along the zone axes [1-bar 01-bar ]. The parameters of both space charge layers - surface potential, thickness of the space charge region and concentration of the surface compensating charges, are calculated. It is estimated that for intrinsic silver sulfide, the effective surface potential of (1-bar 01-bar ) Ag 2 S surface is negative, its value being about -610mV at 400K

Ion beam modifications of near-surface compositions in ternary alloys

International Nuclear Information System (INIS)

Lam, N.Q.; Tang, S.; Yacout, A.M.; Rehn, L.E.; Stubbins, J.F.

1990-11-01

Changes in the surface and subsurface compositions of ternary alloys during elevated-temperature sputtering with inert-gas ions were investigated. Theoretically, a comprehensive kinetic model which includes all the basic processes, such as preferential sputtering, displacement mixing, Gibbsian segregation, radiation-enhanced diffusion and radiation-induced segregation, was developed. This phenomenological approach enabled to predict the effects of each individual process or of a combination of processes on the compositional modification in model alloys. Experimentally, measurements of compositional changes at the surface of a Ag-40at%Au -- 20at%Cu alloy during 3-keV Ne + bombardment at various temperatures were made, using ion scattering spectroscopy. These measurements were interpreted on the basis of the results of theoretical modeling. 8 refs., 2 figs

Synthesis and electromagnetic absorption properties of Ag-coated reduced graphene oxide with MnFe_2O_4 particles

International Nuclear Information System (INIS)

Wang, Yan; Wu, Xinming; Zhang, Wenzhi; Huang, Shuo

2016-01-01

A ternary composite of Ag/MnFe_2O_4/reduced graphene oxide (RGO) was synthesized by a facile hydrothermal method. The morphology, microstructure, magnetic and electromagnetic properties of as-prepared Ag/MnFe_2O_4/RGO composite were characterized by means of XRD, TEM, XPS, VSM and vector network analyzer. The maximum reflection loss (R_L) of Ag/ MnFe_2O_4/RGO composite shows maximum absorption of −38 dB at 6 GHz with the thickness of 3.5 mm, and the absorption bandwidth with the R_L below −10 dB is up to 3.5 GHz (from 3.7 to 7.2 GHz). The result demonstrates that the introduction of Ag significantly leads to the multiple absorbing mechanisms. It is believed that such composite could serve as a powerful candidate for microwave absorber. - Highlights: • A ternary composite of Ag/MnFe_2O_4/reduced graphene oxide (RGO) was synthesized by a facile method. • The morphology, microstructure, magnetic and electromagnetic properties were characterized. • The maximum reflection loss of Ag/MnFe_2O_4/RGO is −38 dB at 6 GHz with a thickness of 3.5 mm. • The composite shows a wide absorption band.

Devitrification behavior and glass-forming ability of Cu-Zr-Ag alloys

International Nuclear Information System (INIS)

Louzguine-Luzgin, Dmitri V.; Xie, Guoqiang; Zhang, Wei; Inoue, Akihisa

2007-01-01

This paper presents an influence of Ag addition on the glass-forming ability and devitrification behavior of Cu-Zr glassy alloys on heating. The crystallization kinetics and structure changes in Cu 45 Zr 45 Ag 10 and Cu 35 Zr 45 Ag 20 glassy alloys on heating were studied by X-ray diffraction, transmission electron microscopy, differential scanning and isothermal calorimetry methods. Based on the results obtained one can assume that the improvement of the glass-forming ability of the Cu-Zr alloys by the addition of Ag is connected with a particular crystallization mechanism and a higher reduced glass-transition temperature of the Cu 45 Zr 45 Ag 10 ternary alloy compared to the binary Cu 55 Zr 45 counterpart. As observed in the present work crystallization of the Cu-Zr-Ag alloys is found to cause embitterment of the samples and should be avoided as these alloys are considered to be used as structural materials. The Cu 35 Zr 45 Ag 20 alloy shows possible submicron-scale phase separation upon annealing

Interpretation of dc and ac conductivity of Ag2O–SeO2–MoO3 glass-nanocomposite-semiconductor

International Nuclear Information System (INIS)

Bhattacharya, Sanjib; Kundu, Ranadip; Das, Anindya Sundar; Roy, Debasish

2015-01-01

Highlights: • Polaron hopping. • Dc and ac conductivity. • Mott's model and Greave's model. • Ag 2 MoO 4 , Ag 2 Mo 2 O 7 and Ag 6 Mo 10 O 33 nanoparticles and SeO 3 and SeO 4 nanoclusters. • XRD and FESEM studies. - Abstract: A new type of semiconducting glass-nanocomposites 0.3Ag 2 O–0.7 (xMoO 3 –(1 − x) SeO 2 ) is prepared by melt-quenching route. The formation of Ag 2 MoO 4 , Ag 2 Mo 2 O 7 and Ag 6 Mo 10 O 33 nanoparticles and SeO 3 and SeO 4 nanoclusters in glass-nanocomposites has been confirmed from X-ray diffraction (XRD) and field emission scanning electron microscopic (FESEM) studies. Fourier transform infrared (FTIR) spectroscopy is employed to find out Se−O stretching vibration as well as stretching vibrations of Mo 2 O 7 2− ions. The dc conductivity of them is studied on the light of polaron hopping approach in a wide temperature range. At low temperatures, variable range hopping model (Mott's model) is employed to analyze the conductivity data. Greave's model is used to predict temperature dependent variable range hopping in the high temperature region. Frequency dependent ac conductivity is well explained on the basis of tunneling. I–V characteristics of the as-prepared samples have also been investigated

High-performance semiconductor optical preamplifier receiver at 10 Gb/s

DEFF Research Database (Denmark)

Mikkelsen, Benny; Jørgensen, Carsten Gudmann; Jensen, N.

1993-01-01

A semiconductor optical preamplifier receiver for bitrates of 10 Gb/s is described. The measured sensitivity is -28 dBm, with a polarization sensitivity of less than 0.5 dB. Using the same transmitter and receiver configuration but with a 980-nm pumped fiber amplifier instead of the semiconductor...... amplifier, the sensitivity is -34 dBm...

Ternary systems

International Nuclear Information System (INIS)

Kagan, D.N.; Hubberstey, P.; Barker, M.G.

1985-01-01

The paper reviews the experimental and theoretical studies carried out on multicomponent alkali metal systems. Solid-liquid phase equilibria studies are mainly concerned with the systems Na-K-Rb and Na-K-Cs, and data on the liquidus temperatures in these systems are presented. The thermodynamic properties of the ternary Na-K-Cs eutectic system have been determined experimentally, and the enthalpy, heat capacity and excess functions of the alloy are given. An analysis of calculational methods used in determining thermodynamic functions of ternary liquid metals systems is described. Finally, data are tabulated for the density, compressibility, saturated vapour pressure, viscosity and thermal conductivity of the ternary Na-K-Cs eutectic system. (UK)

Temperature behaviour of optical parameters in (Ag3AsS3)0.3(As2S3)0.7 thin films

Science.gov (United States)

Kutsyk, Mykhailo M.; Ráti, Yosyp Y.; Izai, Vitalii Y.; Makauz, Ivan I.; Studenyak, Ihor P.; Kökényesi, Sandor; Komada, Paweł; Zhailaubayev, Yerkin; Smailov, Nurzhigit

2015-12-01

(Ag3AsS3)0.3(As2S3)0.7 thin films were deposited onto a quartz substrate by rapid thermal evaporation. The optical transmission spectra of thin films were measured in the temperature range 77-300 K. It is shown that the absorption edge spectra are described by the Urbach rule. The temperature behaviour of absorption spectra was studied, the temperature dependences of energy position of absorption edge and Urbach energy were investigated. The influence of transition from three-dimensional glass to the two-dimensional thin film as well as influence of Ag3AsS3 introduction into As2S3 on the optical parameters of (Ag3AsS3)0.3(As2S3)0.7 were analysed. The spectral and temperature behaviour or refractive index for (Ag3AsS3)0.3(As2S3)0.7 thin film were studied.

Surface-enhanced Raman effect in hybrid metal–semiconductor nanoparticle assemblies

International Nuclear Information System (INIS)

Lughi, Vanni; Bonifacio, Alois; Barbone, Matteo; Marsich, Lucia; Sergo, Valter

2013-01-01

Hybrid metal–semiconductor nanoparticles consisting of silver nanoparticle cores (AgNPs) coated with a layer of CdSe quantum dots (QDs) have been studied by Raman spectroscopy. The hybrid nanoparticles were prepared via electrostatic interaction by mixing aqueous suspensions of QDs and AgNPs, where opposite charges on the AgNPs and QDs surfaces were induced by opportunely selected capping agents. Assemblies of such hybrid nanoparticles show an increased intensity of the Raman spectrum of up to 500 times, when compared to that of the sole QDs. This enhancement is attributed to the SERS effect (Surface-enhanced Raman scattering). Such enhancement of the Raman modes suggests several opportunities for further research, both in imaging and sensing applications.

Special quasirandom structures for binary/ternary group IV random alloys

KAUST Repository

Chroneos, Alexander I.

2010-06-01

Simulation of defect interactions in binary/ternary group IV semiconductor alloys at the density functional theory level is difficult due to the random distribution of the constituent atoms. The special quasirandom structures approach is a computationally efficient way to describe the random nature. We systematically study the efficacy of the methodology and generate a number of special quasirandom cells for future use. In order to demonstrate the applicability of the technique, the electronic structures of E centers in Si1-xGex and Si1-x -yGexSny alloys are discussed for a range of nearest neighbor environments. © 2010 Elsevier B.V. All rights reserved.

Thermodynamic investigation of the ternary mixed aqueous electrolyte (MgCl{sub 2} + MgSO{sub 4}) system by potentiometric method at T = 298.15 K

Energy Technology Data Exchange (ETDEWEB)

Bagherinia, Mohammad A., E-mail: mabagherinia@yahoo.com [Department of Chemistry, Faculty of Science, Lahijan Branch, Islamic Azad University, Lahijan (Iran, Islamic Republic of); Giahi, Masoud; Pournaghdy, Mohammad; Vaghar, Gholam R. [Department of Chemistry, Faculty of Science, Lahijan Branch, Islamic Azad University, Lahijan (Iran, Islamic Republic of)

2012-01-15

Highlights: > In this study we investigated the thermodynamic properties of MgCl{sub 2} + MgSO{sub 4} + H{sub 2}O. > The method used in this work was potentiometric method. > Mg-ISE and the Ag/AgCl electrodes used in this work had a good Nernst response. > The experimental results obeyed the Harned rule. > The Pitzer model could be used to describe this ternary system satisfactorily. - Abstract: This work reports the results of thermodynamic investigation of the ternary mixed-electrolyte system (MgCl{sub 2} + MgSO{sub 4} + H{sub 2}O). The investigation was performed based on Pitzer ion interaction model by using the potentiometric technique at T = 298.15 K. The mean activity coefficients of MgCl{sub 2} in the mixed aqueous electrolyte system were determined on the galvanic cell without liquid junction of the type: Mg-ISE|MgCl{sub 2} (m{sub A}), MgSO{sub 4} (m{sub B}), H{sub 2}O|Ag/AgCl over total ionic strengths from (0.001 to 8.000) mol . kg{sup -1} for different series of salt ratio r (r=m{sub MgCl{sub 2}}/m{sub MgSO{sub 4}}=2.5,5.0,7.5,10.0,15.0 and pure MgCl{sub 2}). The PVC based magnesium ion-selective electrode (Mg-ISE) and the Ag/AgCl electrode used in this work were made in our laboratory and had a reasonably good Nernst response. The experimental results obeyed the Harned rule, and the Pitzer model could be used to describe this ternary system satisfactorily. Pitzer ion-interaction parameters for mixed salts were determined for this system. Then, these parameters ({theta}{sub ClSO{sub 4}}=0.0252{+-}0.0042, {psi}{sub MgClSO{sub 4}}=-0.0049{+-}0.0003) were used to calculate the values of the mean activity coefficients of MgSO{sub 4}, the osmotic coefficients of water ({phi}) and the excess Gibbs free energies of solution (G{sup E}) for the whole series of the studied electrolyte systems.

In situ synthesis of CdS/CdWO4/WO3 heterojunction films with enhanced photoelectrochemical properties

Science.gov (United States)

Zhan, Faqi; Li, Jie; Li, Wenzhang; Yang, Yahui; Liu, Wenhua; Li, Yaomin

2016-09-01

CdS/CdWO4/WO3 heterojunction films on fluorine-doped tin oxide (FTO) substrates are for the first time prepared as an efficient photoanode for photoelectrochemical (PEC) hydrogen generation by an in situ conversion process. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet visible spectrometry (UV-vis) and X-ray photoelectron spectroscopy (XPS). The CdS hollow spheres (∼80 nm) sensitized WO3 plate film with a CdWO4 buffer-layer exhibits increased visible light absorption and a significantly improved photoelectrochemical performance. The photocurrent density at 0 V (vs. Ag/AgCl) of the CdS/CdWO4/WO3 anode is ∼3 times higher than that of the CdWO4/WO3 anode, and ∼9 times higher than that of pure WO3 under illumination. The highest incident-photon-to-current-efficiency (IPCE) value increased from 16% to 63% when the ternary heterojunction was formed. This study demonstrates that the synthesis of ternary composite photocatalysts by the in situ conversion process may be a promising approach to achieve high photoelectric conversion efficiency.

Photoluminescence and photocatalytic activities of Ag/ZnO metal-semiconductor heterostructure

International Nuclear Information System (INIS)

Sarma, Bikash; Deb, Sujit Kumar; Sarma, Bimal K.

2016-01-01

Present article focuses on the photocatalytic activities of ZnO nanorods and Ag/ZnO heterostructure deposited on polyethylene terephthalate (PET) substrate. ZnO nanorods are synthesized by thermal decomposition technique and Ag nanoparticles deposition is done by photo-deposition technique using UV light. X-ray diffraction studies reveal that the ZnO nanorods are of hexagonal wurtzite structure. Further, as-prepared samples are characterized by Scanning Electron Microscopy (SEM), Photoluminescence (PL) spectroscopy and UV-Vis spectroscopy. The surface plasmon resonance response of Ag/ZnO is found at 420 nm. The photocatalytic activities of the samples are evaluated by photocatalytic decolorization of methyl orange (MO) dye with UV irradiation. The degradation rate of MO increases with increase in irradiation time. The degradation of MO follows the first order kinetics. The photocatalytic activity of Ag/ZnO heterostructure is found to be more than that of ZnO nanorods. The PL intensity of ZnO nanorods is stronger than that of the Ag/ZnO heterostructure. The strong PL intensity indicates high recombination rate of photoinduced charge carriers which lowers the photocatalytic activity of ZnO nanorods. The charge carrier recombination is effectively suppressed by introducing Ag nanoparticles on the surface of the ZnO nanorods. This study demonstrates a strong relationship between PL intensity and photocatalytic activity. (paper)

A review of Pb-Sb(As-S, Cu(Ag-Fe(Zn-Sb(As-S, Ag(Pb-Bi(Sb-S and Pb-Bi-S(Te sulfosalt systems from the Boranja orefield, West Serbia

Directory of Open Access Journals (Sweden)

Radosavljević Slobodan A.

2016-01-01

Full Text Available Recent mineralogical, chemical, physical, and crystallographic investigations of the Boranja orefield showed very complex mineral associations and assemblages where sulfosalts have significant role. The sulfosalts of the Boranja orefield can be divided in four main groups: (i Pb-Sb(As-S system with ±Fe and ±Cu; (ii Cu(Ag-Fe(Zn-Sb(As-S system; (iii Ag(Pb-Bi(Sb-S; (iv and Pb-Bi-S(Te system. Spatially, these sulfosalts are widely spread, however, they are the most abundant in the following polymetallic deposits and ore zones: Cu(Bi-FeS Kram-Mlakva; Pb(Ag-Zn-FeS2 Veliki Majdan (Kolarica-Centralni revir-Kojići; Sb-Zn-Pb-As Rujevac; and Pb-Zn-FeS2-BaSO4 Bobija. The multi stage formation of minerals, from skarnhydrothermal to complex hydrothermal with various stages and sub-stages has been determined. All hydrothermal stages and sub-stages of various polymetallic deposits and ore zones within the Boranja orefield are followed by a variety of sulfosalts. [Projekat Ministarstva nauke Republike Srbije, br. OI-176016: Magmatism and geodynamics of the Balkan Peninsula from Mesozoic to present day: Significance for the formation of metallic and non-metallic mineral deposits

In situ growth of Ag nanoparticles on α-Ag2WO4 under electron irradiation: probing the physical principles

Science.gov (United States)

San-Miguel, Miguel A.; da Silva, Edison Z.; Zannetti, Sonia M.; Cilense, Mario; Fabbro, Maria T.; Gracia, Lourdes; Andrés, Juan; Longo, Elson

2016-06-01

Exploiting the plasmonic behavior of Ag nanoparticles grown on α-Ag2WO4 is a widely employed strategy to produce efficient photocatalysts, ozone sensors, and bactericides. However, a description of the atomic and electronic structure of the semiconductor sites irradiated by electrons is still not available. Such a description is of great importance to understand the mechanisms underlying these physical processes and to improve the design of silver nanoparticles to enhance their activities. Motivated by this, we studied the growth of silver nanoparticles to investigate this novel class of phenomena using both transmission electron microscopy and field emission scanning electron microscopy. A theoretical framework based on density functional theory calculations (DFT), together with experimental analysis and measurements, were developed to examine the changes in the local geometrical and electronic structure of the materials. The physical principles for the formation of Ag nanoparticles on α-Ag2WO4 by electron beam irradiation are described. Quantum mechanical calculations based on DFT show that the (001) of α-Ag2WO4 displays Ag atoms with different coordination numbers. Some of them are able to diffuse out of the surface with a very low energy barrier (less than 0.1 eV), thus, initiating the growth of metallic Ag nanostructures and leaving Ag vacancies in the bulk material. These processes increase the structural disorder of α-Ag2WO4 as well as its electrical resistance as observed in the experimental measurements.

Fabrication of worm-like Ag2S nanocrystals under mediation of protein

Indian Academy of Sciences (India)

1College of Chemistry and Chemical Engineering, Pingdingshan University, Pingdingshan 467000, ... inorganic–organic nanocomposites and there is strong interaction between Ag2S and pepsin. ... applied in the fields of photovoltaics, electroluminescence .... method for fabricating Ag2S nanostructure by using proteins.

Loss-of-function and gain-of-function phenotypes of stomatocytosis mutant RhAG F65S

Science.gov (United States)

Stewart, Andrew K.; Shmukler, Boris E.; Vandorpe, David H.; Rivera, Alicia; Heneghan, John F.; Li, Xiaojin; Hsu, Ann; Karpatkin, Margaret; O'Neill, Allison F.; Bauer, Daniel E.; Heeney, Matthew M.; John, Kathryn; Kuypers, Frans A.; Gallagher, Patrick G.; Lux, Samuel E.; Brugnara, Carlo; Westhoff, Connie M.

2011-01-01

Four patients with overhydrated cation leak stomatocytosis (OHSt) exhibited the heterozygous RhAG missense mutation F65S. OHSt erythrocytes were osmotically fragile, with elevated Na and decreased K contents and increased cation channel-like activity. Xenopus oocytes expressing wild-type RhAG and RhAG F65S exhibited increased ouabain and bumetanide-resistant uptake of Li+ and 86Rb+, with secondarily increased 86Rb+ influx sensitive to ouabain and to bumetanide. Increased RhAG-associated 14C-methylammonium (MA) influx was severely reduced in RhAG F65S-expressing oocytes. RhAG-associated influxes of Li+, 86Rb+, and 14C-MA were pharmacologically distinct, and Li+ uptakes associated with RhAG and RhAG F65S were differentially inhibited by NH4+ and Gd3+. RhAG-expressing oocytes were acidified and depolarized by 5 mM bath NH3/NH4+, but alkalinized and depolarized by subsequent bath exposure to 5 mM methylammonium chloride (MA/MA+). RhAG F65S-expressing oocytes exhibited near-wild-type responses to NH4Cl, but MA/MA+ elicited attenuated alkalinization and strong hyperpolarization. Expression of RhAG or RhAG F65S increased steady-state cation currents unaltered by bath Li+ substitution or bath addition of 5 mM NH4Cl or MA/MA+. These oocyte studies suggest that 1) RhAG expression increases oocyte transport of NH3/NH4+ and MA/MA+; 2) RhAG F65S exhibits gain-of-function phenotypes of increased cation conductance/permeability, and loss-of-function phenotypes of decreased and modified MA/MA+ transport, and decreased NH3/NH4+-associated depolarization; and 3) RhAG transports NH3/NH4+ and MA/MA+ by distinct mechanisms, and/or the substrates elicit distinct cellular responses. Thus, RhAG F65S is a loss-of-function mutation for amine transport. The altered oocyte intracellular pH, membrane potential, and currents associated with RhAG or RhAG F65S expression may reflect distinct transport mechanisms. PMID:21849667

Semiconductor detectors in the low countries

International Nuclear Information System (INIS)

Heijne, Erik H.M.

2003-01-01

Several milestones in the development of semiconductor radiation imaging detectors are attributed to scientists from the Low Countries, the Netherlands and Belgium, and a few historical details will be highlighted. The very first usable semiconductor nuclear detector was made in Utrecht, around 1943, in the form of an AgCl crystal. The earliest large-scale application of monolithic, double-sided silicon strip detectors was in the BOL experiment around 1968 at IKO, now NIKHEF, in Amsterdam. The technology developed and patented by Philips and IKO was adapted by the author and coworkers in 1980 to produce the first silicon microstrip detector used for the reconstruction of events in a CERN fixed target experiment. An avalanche of developments then led to worldwide use of silicon microstrip detectors in elementary particle physics, motivated by the capability to reconstruct particles with lifetime ∼10 -12 s, which decay on sub-millimeter scale. The intensive activity in silicon detector R and D culminated in 1991 in the construction of fine-grained 2D monolithic and hybrid pixel detectors that incorporate sophisticated electronic functions in each microscopic detection element, with typical dimensions of 25-100 μm. Besides being a powerful high intensity tracker for particle physics, this device can also be designed as a new X-ray imager, which allows selective counting of individual photons in each pixel at MHz frequency

The Ag-Al-Cu system

Energy Technology Data Exchange (ETDEWEB)

Witusiewicz, V.T. [ACCESS e. V., Intzestr. 5, D-52072 Aachen (Germany)]. E-mail: victor@access.rwth-aachen.de; Hecht, U. [ACCESS e. V., Intzestr. 5, D-52072 Aachen (Germany); Fries, S.G. [ACCESS e. V., Intzestr. 5, D-52072 Aachen (Germany); Rex, S. [ACCESS e. V., Intzestr. 5, D-52072 Aachen (Germany)

2005-01-25

The thermodynamic description of the Ag-Al-Cu system is obtained by modelling the Gibbs energy of all individual phases in the system using the CALPHAD approach. The model parameters have been evaluated, by means of a computer optimisation technique, based on the descriptions of the constituent binaries proposed in the first part of the work and relevant experimental information for ternary alloys both from literature and own experimental measurements. Several vertical and isothermal sections, the liquidus surface and some thermodynamic properties are calculated using the evaluated parameters. A good agreement between the calculations and the experimental data is achieved.

Effects of gold based dimers on structural and electronic properties of MoS{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Kadioglu, Yelda [Department of Physics, Adnan Menderes University, 09100 Aydın (Turkey); Gökoğlu, Gökhan [Department of Physics, Karabük University, 78050 Karabük (Turkey); Aktürk, Olcay Üzengi, E-mail: ouzengi@adu.edu.tr [Department of Electrical & Electronics Engineering, Adnan Menderes University, 09100 Aydın (Turkey); Nanotechnology Application and Research Center, Adnan Menderes University, 09100 Aydın (Turkey)

2017-02-28

Highlights: • Semiconductor MoS{sub 2} shows metallic character by AuPt and AuPd adsorption. • MoS{sub 2} maintains its semiconductor characteristics with a decrease in the band gap values after AuAg, AuCu, and AuAl adsorption. • AuPt adsorbed system is the most stable structure energetically. • AuAl exhibits the weakest adsorption to MoS{sub 2} among the considered dimers. - Abstract: In view of first principles calculations, we investigate the electronic structure redecoration of monolayer MoS{sub 2} upon adsorptions of AuAg, AuPt, AuPd, AuCu, and AuAl bimetallic dimers. Geometrical structure, band structures, electronic density of states, charge density differences of dimer adsorbed MoS{sub 2} systems are presented and discussed. All the systems studied have non-magnetic ground states. Charge transfers occur from dimer to surface except for AuPt adsorption. Our results indicate that the semiconductor MoS{sub 2} maintains its semiconductor character with decreased band gaps upon AuAg, AuCu, and AuAl adsorptions. However, MoS{sub 2} shows metallic behaviour by AuPt and AuPd adsorptions, so Pt-d and Pd-d states cross Fermi level yielding metallic character. AuPt adsorbed system has the highest E{sub ads} value of 3.15 eV indicating the most stable structure energetically among the dimer adsorbed MoS{sub 2} systems considered.

Structural, electronic, elastic and thermal properties of Li{sub 2}AgSb. First-principles calculations

Energy Technology Data Exchange (ETDEWEB)

Li, Ji-Hong [Sichuan Univ., Chengdu (China). Inst. of Atomic and Molecular Physics; Longdong Univ., Qingyang (China). College of Physics and Electronic Engineering; Zhu, Xu-Hui [Sichuan Univ., Chengdu (China). Inst. of Atomic and Molecular Physics; Cheng, Yan [Sichuan Univ., Chengdu (China). Inst. of Atomic and Molecular Physics; Sichuan Univ., Chengdu (China). Key Laboratory of High Energy Density Physics and Technology of Ministry of Education; Ji, Guang-Fu [Chinese Academy of Engineering Physics, Mianyang (China). National Key Laboratory of Shock Wave and Detonation Physics

2015-07-01

Based on the first-principles density functional theory calculations combined with the quasi-harmonic Debye model, the pressure dependencies of the structural, elastic, electronic and thermal properties of Li{sub 2}AgSb were systematically investigated. The calculated lattice parameters and unit cell volume of Li{sub 2}AgSb at the ground state were in good agreement with the available experimental data. The obtained elastic constants, the bulk modulus and the shear modulus revealed that Li{sub 2}AgSb is mechanically stable and behaves in a ductile manner under the applied pressure. The elasticity-relevant properties, the Young's modulus and the Poisson's ratio showed that pressure can enhance the stiffness of Li{sub 2}AgSb and that Li{sub 2}AgSb is mechanically stable up to 20 GPa. The characteristics of the band structure and the partial density of states of Li{sub 2}AgSb were analysed, showing that Li{sub 2}AgSb is a semiconductor with a direct band gap of 217 meV at 0 GPa and that the increasing pressure can make the band structure of Li{sub 2}AgSb become an indirect one. Studies have shown that, unlike temperature, pressure has little effect on the heat capacity and the thermal expansion coefficient of Li{sub 2}AgSb.

Measurement and correlation of (vapor + liquid) equilibrium data for {α-pinene + p-cymene + (S)-(−)-limonene} ternary system at atmospheric pressure

International Nuclear Information System (INIS)

Sun, Lixia; Liao, Dankui; Yang, Zhengyu; Chen, Xiaopeng; Tong, Zhangfa

2013-01-01

Highlights: ► The VLE data of (α-pinene + p-cymene) and (α-pinene + p-cymene + (S)-(−)-limonene) at atmospheric pressure were measured. ► The VLE data of binary system were correlated by four activity coefficient models. ► The ternary VLE data were predicted from binary parameters of the Liebermann–Fried model. ► The constant G 123 E counters plotted on the Roozeboom diagrams. -- Abstract: (Vapor + liquid) equilibrium (VLE) data for binary system of (α-pinene + p-cymene) and ternary system of {α-pinene + p-cymene + (S)-(−)-limonene} were measured at 100.7 kPa using the modified Ellis equilibrium still. The VLE data are thermodynamically consistent. Parameters of the binary system for the four solution models — Liebermann–Fried, Wilson, NRTL, and UNIQUAC — were calculated by referencing least squares method to minimize an objective function based on the total pressure. The ternary system data were predicted with the parameters of Liebermann–Fried model obtained from the pertinent binary systems. The predicted bubble-point temperature and the vapor composition for the ternary system were in good agreement with the experimental results. Smooth representations of the results are used to construct constant excess Gibbs free energy contours on Roozeboom diagrams

Synthesis and luminescence properties of (Zn,Cd)S:Ag nanocrystals by hydrothermal method

International Nuclear Information System (INIS)

Luo Xixian; Cao Wanghe; Zhou Lixin

2007-01-01

ZnS:Ag and (Zn,Cd)S:Ag nanoparticles with particle sizes of about 50 and 150 nm have been prepared by hydrothermal method. The effects of hydrothermal process on the physical and luminescence characteristics are investigated. The photoluminescence intensities of hydrothermal treatment ZnS:Ag samples are 10 times higher than that of non-treated samples after annealing at 800 deg. C

Ternary fission

Indian Academy of Sciences (India)

the energy minimization of all possible ternary breakups of a heavy radioactive nucleus. Further, within the TCM we have analysed the competition between different geometries as well as different positioning of the fragments. Also, an attempt was made to calculate the mass distribution of ternary fission process within the ...

Recent advancements in the development of radiation hard semiconductor detectors for S-LHC

CERN Document Server

Fretwurst, E; Al-Ajili, A A; Alfieri, G; Allport, P P; Artuso, M; Assouak, S; Avset, B S; Barabash, L; Barcz, A; Bates, R; Biagi, S F; Bilei, G M; Bisello, D; Blue, A; Blumenau, A; Boisvert, V; Bölla, G; Bondarenko, G B; Borchi, E; Borrello, L; Bortoletto, D; Boscardin, M; Bosisio, L; Bowcock, T J V; Brodbeck, T J; Broz, J; Bruzzi, M; Brzozowski, A; Buda, M; Buhmann, P; Buttar, C; Campabadal, F; Campbell, D; Candelori, A; Casse, G; Cavallini, A; Charron, S; Chilingarov, A G; Chren, D; Cindro, V; Collins, P; Coluccia, R; Contarato, D; Coutinho, J; Creanza, D; Cunningham, L; Dalla Betta, G F; Dawson, I; de Boer, Wim; De Palma, M; Demina, R; Dervan, P; Dittongo, S; Dolezal, Z; Dolgolenko, A; Eberlein, T; Eremin, V; Fall, C; Fasolo, F; Ferbel, T; Fizzotti, F; Fleta, C; Focardi, E; Forton, E; García, C; García-Navarro, J E; Gaubas, E; Genest, M H; Gill, K A; Giolo, K; Glaser, M; Gössling, C; Golovine, V; González-Sevilla, S; Gorelov,I; Goss, J; Gouldwell-Bates, A; Grégoire, G; Gregori, P; Grigoriev, E; Grillo, A A; Groza, A; Guskov, J; Haddad, L; Härkönen, J; Hauler, F; Hoeferkamp, M; Honniger, F; Horazdovsky, T; Horisberger, R P; Horn, M; Houdayer, A; Hourahine, B; Hughes, G; Ilyashenko, Yu S; Irmscher, K; Ivanov, A; Jarasiunas, K; Johansen, K M H; Jones, B K; Jones, R; Joram, C; Jungermann, L; Kalinina, E; Kaminski, P; Karpenko, A; Karpov, A; Kazlauskiene, V; Kazukauskas, V; Khivrich, V; Khomenkov, V P; Kierstead, J A; Klaiber Lodewigs, J M; Klingenberg, R; Kodys, P; Kohout, Z; Korjenevski, S; Koski, M; Kozlowski, R; Kozodaev, M; Kramberger, G; Krasel, O; Kuznetsov, A; Kwan, S; Lagomarsino, S; Lassila-Perini, K M; Lastovetsky, V F; Latino, G; Lazanu, I; Lazanu, S; Lebedev, A; Lebel, C; Leinonen, K; Leroy, C; Li, Z; Lindström, G; Linhart, V; Litovchenko, P G; Litovchenko, A P; Lo Giudice, A; Lozano, M; Luczynski, Z; Luukka, Panja; Macchiolo, A; Makarenko, L F; Mandic, I; Manfredotti, C; Manna, N; Martí i García, S; Marunko, S; Mathieson, K; Melone, J; Menichelli, D; Messineo, A; Metcalfe, J; Miglio, S; Mikuz, M; Miyamoto, J; Moll, M; Monakhov, E; Moscatelli, F; Naoumov, D; Nossarzhevska, E; Nysten, J; Olivero, P; O'Shea, V; Palviainen, T; Paolini, C; Parkes, C; Passeri, D; Pein, U; Pellegrini, G; Perera, L; Petasecca, M; Piemonte, C; Pignatel, G U; Pinho, N; Pintilie, I; Pintilie, L; Polivtsev, L; Polozov, P; Popa, A; Populea, J; Pospísil, S; Pozza, A; Radicci, V; Rafí, J M; Rando, R; Röder, R; Rohe, T; Ronchin, S; Rott, C; Roy, A; Ruzin, A; Sadrozinski, H F W; Sakalauskas, S; Scaringella, M; Schiavulli, L; Schnetzer, S; Schumm, B; Sciortino, S; Scorzoni, A; Segneri, G; Seidela, S; Seiden, A; Sellberg, G; Sellin, P J; Sentenac, D; Shipsey, I; Sícho, P; Sloan, T; Solar, M; Son, S; Sopko, B; Sopko, V; Spencer, N; Stahl, J; Stolze, D; Stone, R; Storasta, J; Strokan, N; Sudzius, M; Surma, B; Suvorov, A; Svensson, B G; Tipton, P; Tomasek, M; Tsvetkov, A; Tuominen, E; Tuovinen, E; Tuuva, T; Tylchin, M; Uebersee, H; Uher, J; Ullán, M; Vaitkus, J V; Velthuis, J; Verbitskaya, E; Vrba, V; Wagner, G; Wilhelm, I; Worm, S; Wright, V; Wunstorf, R; Yiuri, Y; Zabierowski, P; Zaluzhny, A; Zavrtanik, M; Zen, M; Zhukov, V; Zorzi, N

2005-01-01

The proposed luminosity upgrade of the Large Hadron Collider (S-LHC) at CERN will demand the innermost layers of the vertex detectors to sustain fluences of about 1016 hadrons/cm2. Due to the high multiplicity of tracks, the required spatial resolution and the extremely harsh radiation field new detector concepts and semiconductor materials have to be explored for a possible solution of this challenge. The CERN RD50 collaboration “Development of Radiation Hard Semiconductor Devices for Very High Luminosity Colliders” has started in 2002 an R&D program for the development of detector technologies that will fulfill the requirements of the S-LHC. Different strategies are followed by RD50 to improve the radiation tolerance. These include the development of defect engineered silicon like Czochralski, epitaxial and oxygen-enriched silicon and of other semiconductor materials like SiC and GaN as well as extensive studies of the microscopic defects responsible for the degradation of irradiated sensors. Furthe...

A bamboo-inspired hierarchical nanoarchitecture of Ag/CuO/TiO_2 nanotube array for highly photocatalytic degradation of 2,4-dinitrophenol

International Nuclear Information System (INIS)

Zhang, Xuhong; Wang, Longlu; Liu, Chengbin; Ding, Yangbin; Zhang, Shuqu; Zeng, Yunxiong; Liu, Yutang; Luo, Shenglian

2016-01-01

Highlights: • Bamboo-like architecture of ternary photocatalyst. • High simulated solar light photocatalytic activity. • Integration of p-n heterojunction and Schottky junction. • Excellent stable recycling performance. - Abstract: The optimized geometrical configuration of muitiple active materials into hierarchical nanoarchitecture is essential for the creation of photocatalytic degradation system that can mimic natural photosynthesis. A bamboo-like architecture, CuO nanosheets and Ag nanoparticles co-decorated TiO_2 nanotube arrays (Ag/CuO/TiO_2), was fabricated by using simple solution-immersion and electrodeposition process. Under simulated solar light irradiation, the 2,4-dinitrophenol (2,4-DNP) photocatalytic degradation rate over Ag/CuO/TiO_2 was about 2.0, 1.5 and 1.2 times that over TiO_2 nanotubes, CuO/TiO_2 and Ag/TiO_2, respectively. The enhanced photocatalytic activity of ternary Ag/CuO/TiO_2 photocatalyst was ascribed to improved light absorption, reduced carrier recombination and more exposed active sites. Moreover, the excellent stability and reliability of the Ag/CuO/TiO_2 photocatalyst demonstrated a promising application for organic pollutant removal from water.

Ternary diffusion in Cu-rich fcc Cu–Al–Si alloys at 1073 K

Energy Technology Data Exchange (ETDEWEB)

Liu, Dandan [School of Materials Science and Engineering, Central South University, Changsha, Hunan 410083 (China); State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Zhang, Lijun [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Du, Yong, E-mail: yongducalphad@gmail.com [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Xu, Honghui [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Jin, Zhanpeng [School of Materials Science and Engineering, Central South University, Changsha, Hunan 410083 (China)

2013-07-25

Highlights: •Interdiffusivities in Cu-rich fcc Cu–Al–Si alloys at 1073 K were determined. •The present results were compared with experimental data in boundary binary systems. •The present results were validated by thermodynamic constraints and Fick’s law. •The sign of ternary cross diffusivities was predicted in terms of thermodynamics. -- Abstract: Utilizing six groups of bulk diffusion couples and with electron probe microanalysis technique, the composition dependence of ternary interdiffusion coefficients in Cu-rich fcc Cu–Al–Si alloys at 1073 K were determined by the Matano-Kirkaldy method. Using a three-dimensional representation, the obtained main ternary diffusion coefficients were found to be consistent with the experimental data in boundary binaries available in the literature. The reliability of the obtained interdiffusivities was further validated by thermodynamic constraints as well as by Fick’s second law applied to numerical simulation. The sign of the ternary cross diffusivities in fcc Cu–Al–Si alloys, which shows a noticeable effect on microstructure, was also successfully predicted in terms of thermodynamics.

Ternary diffusion in Cu-rich fcc Cu–Al–Si alloys at 1073 K

International Nuclear Information System (INIS)

Liu, Dandan; Zhang, Lijun; Du, Yong; Xu, Honghui; Jin, Zhanpeng

2013-01-01

Highlights: •Interdiffusivities in Cu-rich fcc Cu–Al–Si alloys at 1073 K were determined. •The present results were compared with experimental data in boundary binary systems. •The present results were validated by thermodynamic constraints and Fick’s law. •The sign of ternary cross diffusivities was predicted in terms of thermodynamics. -- Abstract: Utilizing six groups of bulk diffusion couples and with electron probe microanalysis technique, the composition dependence of ternary interdiffusion coefficients in Cu-rich fcc Cu–Al–Si alloys at 1073 K were determined by the Matano-Kirkaldy method. Using a three-dimensional representation, the obtained main ternary diffusion coefficients were found to be consistent with the experimental data in boundary binaries available in the literature. The reliability of the obtained interdiffusivities was further validated by thermodynamic constraints as well as by Fick’s second law applied to numerical simulation. The sign of the ternary cross diffusivities in fcc Cu–Al–Si alloys, which shows a noticeable effect on microstructure, was also successfully predicted in terms of thermodynamics

Attapulgite-CeO{sub 2}/MoS{sub 2} ternary nanocomposite for photocatalytic oxidative desulfurization

Energy Technology Data Exchange (ETDEWEB)

Li, Xiazhang, E-mail: lixiazhang509@163.com [Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Changzhou University, Changzhou 213164 (China); Jiangsu Key Laboratory for Environment Functional Materials, Suzhou University of Science and Technology, Suzhou 215009 (China); W.M.Keck Center for Advanced Microscopy and Microanalysis, University of Delaware, Newark, DE 19716 (United States); Zhang, Zuosong [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China); Yao, Chao [Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Changzhou University, Changzhou 213164 (China); Lu, Xiaowang [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China); Zhao, Xiaobing [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China); Jiangsu Key Laboratory for Environment Functional Materials, Suzhou University of Science and Technology, Suzhou 215009 (China); Ni, Chaoying [W.M.Keck Center for Advanced Microscopy and Microanalysis, University of Delaware, Newark, DE 19716 (United States)

2016-02-28

Graphical abstract: - Highlights: • Novel attapulgite(ATP)-CeO{sub 2}/MoS{sub 2} ternary nanocomposites were fabricated. • ATP possessed outstanding adsorption property and enhanced the stability of the network structure. • CeO{sub 2}/MoS{sub 2} couples facilitated the separation of photo-induced electrons and holes. • Mass ratio of CeO{sub 2}/MoS{sub 2} influenced the photocatalytic oxidation desulfurization. - Abstract: Novel attapulgite(ATP)-CeO{sub 2}/MoS{sub 2} ternary nanocomposites were synthesized by microwave assisted assembly method. The structures of the nanocomposites were characterized by XRD, FT-IR, UV–vis, XPS and in situ TEM. The photocatalytic activities of ATP-CeO{sub 2}/MoS{sub 2} composites were investigated by degradating dibenzothiophene (DBT) in gasoline under visible light irradiation. The effect of the mass ratio of CeO{sub 2} to MoS{sub 2} on photocatalytic activity was investigated. The results indicate that the three-dimensional network structure is firmly constructed by ATP skeleton, CeO{sub 2} particles and MoS{sub 2} nanosheet which effectively increase the surface area of the composites and promote the separation of electrons and holes by resulting electronic transmission channels of multi-channel in space. The degradation rate of DBT can reach 95% under 3 h irradiation when the mass ratio of CeO{sub 2}/MoS{sub 2} is 4/10. A plausible mechanism for the photocatalytic oxidative desulfurization of this nanocomposite is put forward.

Electron-transfer reactions of extremely small AgI colloids

International Nuclear Information System (INIS)

Vucemilovic, M.I.; Micic, O.I.

1988-01-01

Small colloidal AgI particles (particle diameter 20-50 A) have been prepared in water and acetonitrile, and optical effects due to size quantization have been observed. Electron transfer reactions involving electron donors and electron acceptors with AgI have been studied by pulse radiolysis techniques. Both reduction and oxidation of the colloids led to transient bleaching of semiconductor absorption. The recovery of the bleaching has been attributed to corrosion processes. Electrons injected into AgI colloids produce metallic silver and hydrogen. Hydrogen evolution is catalyzed by metallic silver formation. (author)

Study of adsorption states in ZnO—Ag gas-sensitive ceramics using the ECTV curves method

Directory of Open Access Journals (Sweden)

Lyashkov A. Yu.

2013-12-01

Full Text Available The ZnO—Ag ceramic system as the material for semiconductor sensors of ethanol vapors was proposed quite a long time ago. The main goal of this work was to study surface electron states of this system and their relation with the electric properties of the material. The quantity of doping with Ag2O was changed in the range of 0,1–2,0% of mass. The increase of the Ag doping leads to a shift of the Fermi level down (closer to the valence zone. The paper presents research results on electrical properties of ZnO-Ag ceramics using the method of thermal vacuum curves of electrical conductivity. Changes in the electrical properties during heating in vacuum in the temperature range of 300—800 K were obtained and discussed. The increase of Tvac leads to removal of oxygen from the surface of samples The oxygen is adsorbed in the form of O2– and O– ions and is the acceptor for ZnO. This results in the lowering of the inter-crystallite potential barriers in the ceramic. The surface electron states (SES above the Fermi level are virtually uncharged. The increase of the conductivity causes desorption of oxygen from the SES settled below the Fermi level of the semiconductor. The model allows evaluating the depth of the Fermi level in the inhomogeneous semiconductor materials.

Determination of 210Po in Slovak mineral waters by sorption on ZnS(Ag)

International Nuclear Information System (INIS)

Krivosik, M.

2009-01-01

In determining of 210 Po it was followed according to the Czech technical standard CSN 75 7626 Water quality - Determination of polonium-210. The aim of this work was to optimize the conditions for sorption of 210 Po on ZnS (Ag) from acidic environment from the model solutions. The effect of pH of the sample, its volume and the presence of NaCl on the sorption of 210 Po on ZnS (Ag) was studied. Three types of filters for filtering ZnS (Ag), Synpor, paper and glass fiber filters were tested. Bulk activity of 210 Po was determined in the samples of Slovak mineral waters and healing waters as well as in water samples from antimony mine (mine Rufus) near the village Poproc (rural Kosice district). (author)

Investigation of AgInS{sub 2} thin films grown by coevaporation

Energy Technology Data Exchange (ETDEWEB)

Arredondo, C A; Gordillo, G [Departamento de Fisica, Universidad Nacional de Colombia, Bogota (Colombia); J, Clavijo, E-mail: caarredondoo@unal.edu.c, E-mail: ggordillog@unal.edu.c [Departamento de Quimica, Universidad Nacional de Colombia, Bogota, Cr.30 N0 45-03 (Colombia)

2009-05-01

AgInS{sub 2} thin films were grown on soda-lime glass substrates by co-evaporation of the precursors in a two-step process. X-ray diffraction (XRD) measurements indicated that these compounds grow in different phases and with different crystalline structure depending upon the deposition conditions. However, through a parameter study, conditions were found to grow thin films containing only the AgInS{sub 2} phase with chalcopyrite type structure. In samples containing a mixture of several phases, the contribution in percentage terms of each phase to the whole compound was estimated with the help of the PowderCell simulation package. It was also found that the AgInS{sub 2} films present p-type conductivity, a high absorption coefficient (greater than 10{sub 4} cm{sub -1}) and an energy band gap Eg of about 1.95 eV, indicating that this compound has good properties to perform as absorbent layer in thin film tandem solar cells. The effect of the deposition conditions on the optical and morphological properties was also investigated through spectral transmitance and atomic force microscopy (AFM) measurements.

A bamboo-inspired hierarchical nanoarchitecture of Ag/CuO/TiO{sub 2} nanotube array for highly photocatalytic degradation of 2,4-dinitrophenol

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xuhong; Wang, Longlu [State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082 (China); Liu, Chengbin, E-mail: chem_cbliu@hnu.edu.cn [State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082 (China); Ding, Yangbin; Zhang, Shuqu; Zeng, Yunxiong [State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082 (China); Liu, Yutang, E-mail: liuyutang@126.com [Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Luo, Shenglian [State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082 (China)

2016-08-05

Highlights: • Bamboo-like architecture of ternary photocatalyst. • High simulated solar light photocatalytic activity. • Integration of p-n heterojunction and Schottky junction. • Excellent stable recycling performance. - Abstract: The optimized geometrical configuration of muitiple active materials into hierarchical nanoarchitecture is essential for the creation of photocatalytic degradation system that can mimic natural photosynthesis. A bamboo-like architecture, CuO nanosheets and Ag nanoparticles co-decorated TiO{sub 2} nanotube arrays (Ag/CuO/TiO{sub 2}), was fabricated by using simple solution-immersion and electrodeposition process. Under simulated solar light irradiation, the 2,4-dinitrophenol (2,4-DNP) photocatalytic degradation rate over Ag/CuO/TiO{sub 2} was about 2.0, 1.5 and 1.2 times that over TiO{sub 2} nanotubes, CuO/TiO{sub 2} and Ag/TiO{sub 2}, respectively. The enhanced photocatalytic activity of ternary Ag/CuO/TiO{sub 2} photocatalyst was ascribed to improved light absorption, reduced carrier recombination and more exposed active sites. Moreover, the excellent stability and reliability of the Ag/CuO/TiO{sub 2} photocatalyst demonstrated a promising application for organic pollutant removal from water.

Electronic transport in heavily doped Ag/n-Si composite films

Directory of Open Access Journals (Sweden)

Clayton W. Bates Jr.

2013-10-01

Full Text Available Hall measurements characterized Ag/n-Si composite films 1 micron thick produced by magnetron co-sputtering onto high resistivity Si (111 substrates at 550°C. The targets were Ag and n-type Si doped with 3 × 1019/cm3 of antimony. Films were prepared with 13, 16 and 22 at. % Ag and measured over a temperature range 77–500°K. Conduction takes place at low temperatures by variable rang hopping in localized states at the Fermi level and by thermal activation over grain boundaries at higher temperatures. The Log Resistivity vs 1/kT curves for the three Ag concentrations vary in a similar manner, but decrease in magnitude with increasing Ag due to the smaller number of grain boundaries between Ag nanoparticles occurring with increasing Ag concentration. At low temperatures Hall mobilities are essentially independent of temperature as the carrier densities for the three Ag concentrations are constant from 77 to slightly under 300°K with resistivities varying by small amounts. The mobilities at all Ag concentrations increase with temperature and approach each other as the effects of grain boundaries become less important. This work presents for the first time the effects of metal particles embedded in a semiconductor on the transport properties of carriers in the semiconductor. Though these effects are for a given average particle size most of the results are expected to hold over a range of particle sizes. Free electrons produced in films containing 13 and 16 at. % Ag result in concentrations of 1.5 × 1019/cm3, one half the antimony doping, while those with 22 at. % Ag, the carrier concentrations are three orders of magnitude higher. These constant carrier concentrations are due to the metal-insulator transition that occurs in doped crystalline and polycrystalline silicon for carrier densities nc >3.9 × 1018/cm3. The three orders of magnitude higher carrier concentration produced in films with 22 at. % Ag is argued to be due to doping of the Si

Binary and ternary systems

International Nuclear Information System (INIS)

Petrov, D.A.

1986-01-01

Conditions for thermodynamical equilibrium in binary and ternary systems are considered. Main types of binary and ternary system phase diagrams are sequently constructed on the basis of general regularities on the character of transition from one equilibria to others. New statements on equilibrium line direction in the diagram triple points and their isothermal cross sections are developed. New represenations on equilibria in case of monovariant curve minimum and maximum on three-phase equilibrium formation in ternary system are introduced

Enhanced selective photocatalytic CO{sub 2} reduction into CO over Ag/CdS nanocomposites under visible light

Energy Technology Data Exchange (ETDEWEB)

Zhu, Zezhou; Qin, Jiani; Jiang, Min; Ding, Zhengxin; Hou, Yidong, E-mail: ydhou@fzu.edu.cn

2017-01-01

Highlights: • Ag/CdS nanocomposites were prepared by a facile photodeposition method. • Ag/CdS was more effective as a photocatalyst for CO{sub 2} reduction than CdS. • Ag as cocatalyst served as electron trap as well as active site for CO{sub 2} reduction reaction. - Abstract: Photocatalytic reduction of carbon dioxide can convert chemically inert carbon dioxide into useful chemical fuel in a mild manner. Herein, Ag-CdS nanocomposites were prepared by photodeposition method and examined for photocatalytic CO{sub 2} reduction under visible light. Meanwhile, the nanocomposites were characterized by XRD, SEM, TEM, XPS, DRS and PL in detail. The results show that, the deposition of Ag improves the photocatalytic performance of CdS, especially in the selectivity of CO{sub 2}-to-CO. The highest photocatalytic activity is achieved over 1.0 wt.% Ag/CdS, with an increase by 3 times in comparison to CdS. In this reaction system, Ag can serve as electron trap as well as active site for CO{sub 2} reduction, which is probably responsible for the enhanced activity and selectivity of CO{sub 2} to CO over Ag/CdS. The possible mechanism of CO{sub 2} photoreduction over Ag/CdS was proposed in view of the abovementioned analysis.

Optical and semiconductive properties of binary and ternary thin films from the Nb-Ti-O system

Science.gov (United States)

Aperador, W.; Yate, L.; Pinzón, M. J.; Caicedo, J. C.

2018-06-01

A study has been conducted based on the Mott-Schottky model acquisition by potentiodynamic electrochemical impedance spectroscopy, to determine the physical-chemical properties of binary TiO2, Nb2O5 and ternary Nb-Ti-O thin films (semiconductor type) based on Nb,Ti, O elements. The technique used for the study of optical properties was that of spectral transmittance, measurements were performed using a spectrophotometer. The consistency of the impedance data has been studied by calculating the Kramers-Kronig relations. The structural properties were analyzed by XRD patterns; the chemical composition measurements for all thin films were made by using XPS technique. So, in this research the transmittance values change from 72.74% for Nb2O5 to 59.68% for Ti-Nb-O with wavelength around 355 nm. The absorption coefficients for all films were analyzed from 31823.87 cm-1 for Nb2O5 to 91240.90 cm-1 for Nb-Ti-O with wavelength around 355 nm evidencing thus a 65% reduction. The direct band gap it was found that the photon energy (band gap Eg) changes in all films from 3.56 eV for Nb2O5 to 3.96 eV for Ti-Nb-O evidencing a 10% reduction. The extinction coefficient values change in all films from 0.038 cm-1 for Nb2O5 to 0.277 cm-1 for Ti-Nb-O films with wavelength around 355 nm, exhibiting an 86% increasing. Finally, it was observed by the Mott-Schottky analysis that the reference potential (Ag/AgCl) changes for all films from -2.09 V for Nb2O5 to -0.80 V for Ti-Nb-O material showing a 62% reduction.

Thermal analysis and prediction of phase equilibria in ternary Pb-Zn-Ag System

Czech Academy of Sciences Publication Activity Database

Živković, D.; Minić, D.; Manasijević, D.; Šesták, Jaroslav; Živković, Ž.

2011-01-01

Roč. 47, č. 1 (2011), 23-30 ISSN 1450-5339 Institutional research plan: CEZ:AV0Z10100521 Keywords : Pb-Zn-Ag system * thermal analysis * phase equilibrium Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.317, year: 2011

Outstanding laser damage threshold in Li2MnGeS4 and tunable optical nonlinearity in diamond-like semiconductors.

Science.gov (United States)

Brant, Jacilynn A; Clark, Daniel J; Kim, Yong Soo; Jang, Joon I; Weiland, Ashley; Aitken, Jennifer A

2015-03-16

The new Li2MnGeS4 and Li2CoSnS4 compounds result from employing a rational and simple design strategy that guides the discovery of diamond-like semiconductors (DLSs) with wide regions of optical transparency, high laser damage threshold, and efficient second-order optical nonlinearity. Single-crystal X-ray diffraction was used to solve and refine the crystal structures of Li2MnGeS4 and Li2CoSnS4, which crystallize in the noncentrosymmetric space groups Pna21 and Pn, respectively. Synchrotron X-ray powder diffraction (SXRPD) was used to assess the phase purity, and diffuse reflectance UV-vis-NIR spectroscopy was used to estimate the bandgaps of Li2MnGeS4 (Eg = 3.069(3) eV) and Li2CoSnS4 (Eg = 2.421(3) eV). In comparison with Li2FeGeS4, Li2FeSnS4, and Li2CoSnS4 DLSs, Li2MnGeS4 exhibits the widest region of optical transparency (0.60-25 μm) and phase matchability (≥1.6 μm). All four of the DLSs exhibit second-harmonic generation and are compared with the benchmark NLO material, AgGaSe2. Most remarkably, Li2MnGeS4 does not undergo two- or three-photon absorption upon exposure to a fundamental Nd:YAG beam (λ = 1.064 μm) and exhibits a laser damage threshold > 16 GW/cm(2).

Studies of optical properties and applications of some mixed ternary semiconductors

International Nuclear Information System (INIS)

Ghosh, P.S.; Ghosh, D.K.; Samanta, L.K.

1989-01-01

Refractive indices of some mixed compound semiconductors below the bandgap are presented on the basis of some fundamental parameters and the effect of lattice mismatch on the refractive index step is also studied. The results help to design a variety of opto-electronic devices for the use in optical fiber communication and heterostructure lasers. The calculated values agree well with available experimental values thus justifying the approach. (author)

Copper substitutions in synthetic miargyrite α-AgSbS{sub 2} mineral: Synthesis, characterization and dielectrical properties

Energy Technology Data Exchange (ETDEWEB)

Galdámez, A., E-mail: agaldamez@uchile.cl [Departamento de Química, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); López-Vergara, F.; Veloso Cid, N.; Manríquez, V. [Departamento de Química, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Ávila, R.E. [Departamento de Producción y Servicios, Comisión Chilena de Energía Nuclear, Casilla 188-D, Santiago (Chile)

2014-02-14

The nominal compositions Ag{sub 0.8}Cu{sub 0.2}SbS{sub 2} and Ag{sub 0.7}Cu{sub 0.3}SbS{sub 2} have been synthesized by conventional ceramic solid-state reaction at high temperature. X-ray diffraction (XRD) and scanning electron microscopy chemical analysis (SEM-EDAX) revealed single phases, isostructural to the natural miargyrite α-AgSbS{sub 2} mineral. Examination of the lattice parameters shows a decrease in the cell volume with increasing copper substitutions. The Raman analysis displays absorptions which may be assigned to the Sb–S stretching vibrations of the SbS{sub 3} pyramids. The impedance-frequency analysis showed grain boundary and electrode interface contributions in non-Debye type relaxation, following Jonscher's universal power law. The giant permittivity response is attributed to extrinsic effects without evidence of a ferroelectric transition. Summerfield scaling, leading to the superposition of impedance analysis, implies that the relaxation is thermally activated, without introducing more than one underlying transport mechanism. - Highlights: • Ag{sub 0.8}Cu{sub 0.2}SbS{sub 2} and Ag{sub 0.7}Cu{sub 0.3}SbS{sub 2} are isostructural with the natural miargyrite α-AgSbS{sub 2} mineral. • The overall resistance correspond to grain boundary and electrode/sample interface responses. • In these solid solutions no ferroelectric-like transition is noticed. • The overall frequency dependence follows the Jonscher's universal power law. • σ{sub ac} vs. frequency can be normalized by Summerfield scaling procedure.

Effect of CdS Growth Time on the Optical Properties of One-Pot Preparation of CdS-Ag2S Binary Compounds

Science.gov (United States)

Karimipour, M.; Izadian, L.; Molaei, M.

2018-02-01

CdS-Ag2S binary nanoparticles were synthesized using a facile one-pot microwave irradiation method. The effect of initial nucleation of CdS quantum dots (QDs) using 3 min, 5 min, and 7 min of microwave irradiation on the optical properties of the final compound was studied. The composition and crystal structure of the compounds were verified using energy dispersive x-ray spectroscopy and x-ray diffraction. They revealed that existence of Ag and Cd elements with an atomic ratio of 0.19 crystalizes in the form of monoclinic Ag2S and hexagonal CdS. Scanning electron microscope images showed a spherical morphology of the resultant compound, and transmission electron microscope images showed the formation of fine particles of CdS-Ag2S composites with an average size of 5-7 nm and 10-14 nm for CdS and Ag2S, respectively. Photoluminescence spectroscopy revealed that the initial growth time of CdS has a crucial effect on the emission of binary compounds such that for 3 min and 5 min of irradiation of CdS solution, the binary compound obtains strong red and considerable near-IR emission (850 nm), but for longer time, it rapidly quenches. The results indicate that the strong red emission can be tuned from 600 nm up to 700 nm with prolonging nucleation time of CdS. This study also emphasized that the origin of red emission strongly depends on the size and defects created in the CdS QDs.

Synthesis of Mn-doped ZnS architectures in ternary solution and their optical properties

Energy Technology Data Exchange (ETDEWEB)

Wang Xinjuan, E-mail: wangxj@hnu.edu.cn [State Key lab of CBSC, Micronano Research Center, Hunan University, Changsha 410082 (China); Zhang Qinglin [State Key lab of CBSC, Micronano Research Center, Hunan University, Changsha 410082 (China); Zou Bingsuo, E-mail: zoubs@bit.edu.cn [State Key lab of CBSC, Micronano Research Center, Hunan University, Changsha 410082 (China); Micro-nano Technology Center and School of MSE, BIT, Beijing 100081 (China); Lei Aihua; Ren Pinyun [State Key lab of CBSC, Micronano Research Center, Hunan University, Changsha 410082 (China)

2011-10-01

Mn-doped ZnS sea urchin-like architectures were fabricated by a one-pot solvothermal route in a ternary solution made of ethylenediamine, ethanolamine and distilled water. The as-prepared products were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and photoluminescence spectra (PL). It was demonstrated that the as-prepared sea urchin-like architectures with diameter of 0.5-1.5 {mu}m were composed of nanorods, possessing a wurtzite structures. The preferred growth orientation of nanorods was found to be the [0 0 2] direction. The PL spectra of the Mn-doped ZnS sea urchin-like architectures show a strong orange emission at 587 nm, indicating the successful doping of Mn{sup 2+} ions into ZnS host. Ethanolamine played the role of oriented-assembly agent in the formation of sea urchin-like architectures. A possible growth mechanism was proposed to explain the formation of sea urchin-like architectures.

Synthesis of Mn-doped ZnS architectures in ternary solution and their optical properties

International Nuclear Information System (INIS)

Wang Xinjuan; Zhang Qinglin; Zou Bingsuo; Lei Aihua; Ren Pinyun

2011-01-01

Mn-doped ZnS sea urchin-like architectures were fabricated by a one-pot solvothermal route in a ternary solution made of ethylenediamine, ethanolamine and distilled water. The as-prepared products were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and photoluminescence spectra (PL). It was demonstrated that the as-prepared sea urchin-like architectures with diameter of 0.5-1.5 μm were composed of nanorods, possessing a wurtzite structures. The preferred growth orientation of nanorods was found to be the [0 0 2] direction. The PL spectra of the Mn-doped ZnS sea urchin-like architectures show a strong orange emission at 587 nm, indicating the successful doping of Mn 2+ ions into ZnS host. Ethanolamine played the role of oriented-assembly agent in the formation of sea urchin-like architectures. A possible growth mechanism was proposed to explain the formation of sea urchin-like architectures.

A comparative study about electronic structures at rubrene/Ag and Ag/rubrene interfaces

Directory of Open Access Journals (Sweden)

Sumona Sinha

2015-10-01

Full Text Available The contact between the electrode and the organic semiconductor is one of the most crucial factors in determining the organic device performance. The development and production technology of different organic devices require the understanding of different types of metal/organic semiconducting thin film interfaces. Comparisons about the electronic structures at Rubrene/Ag and Ag/Rubrene interfaces have been studied using photoemission spectroscopy. The Ag on rubrene interfaces is found to show more interesting and complex natures than its counterpart. The vacuum level (VL was shifted about 0.51 eV from push back effect for deposition of 5 Å rubrene onto Ag film whereas the electronic features of silver was only suppressed and no energy shift was resulted. While the deposition of 5 Å Ag onto rubrene film leads to the diffusion of the Ag atoms, as a cluster with quantum size effect, inside the film. Angle dependent XPS measurement indicates that diffused metal clusters were present at entire probed depth of the film. Moreover these clusters dope the uppermost surface of the rubrene film which consequences a shift of the electronic states of thick organic film towards higher binding energy. The VL was found to shift about 0.31 eV toward higher binding energy whereas the shift was around 0.21 eV for the electronic states of rubrene layer.

A comparative study about electronic structures at rubrene/Ag and Ag/rubrene interfaces

Energy Technology Data Exchange (ETDEWEB)

Sinha, Sumona, E-mail: sumona.net.09@gmail.com; Mukherjee, M. [Saha Institute of Nuclear Physics, 1/AF, Bidhan Nagar, Kolkata 700064 (India)

2015-10-15

The contact between the electrode and the organic semiconductor is one of the most crucial factors in determining the organic device performance. The development and production technology of different organic devices require the understanding of different types of metal/organic semiconducting thin film interfaces. Comparisons about the electronic structures at Rubrene/Ag and Ag/Rubrene interfaces have been studied using photoemission spectroscopy. The Ag on rubrene interfaces is found to show more interesting and complex natures than its counterpart. The vacuum level (VL) was shifted about 0.51 eV from push back effect for deposition of 5 Å rubrene onto Ag film whereas the electronic features of silver was only suppressed and no energy shift was resulted. While the deposition of 5 Å Ag onto rubrene film leads to the diffusion of the Ag atoms, as a cluster with quantum size effect, inside the film. Angle dependent XPS measurement indicates that diffused metal clusters were present at entire probed depth of the film. Moreover these clusters dope the uppermost surface of the rubrene film which consequences a shift of the electronic states of thick organic film towards higher binding energy. The VL was found to shift about 0.31 eV toward higher binding energy whereas the shift was around 0.21 eV for the electronic states of rubrene layer.

Synthesis and properties of new CdSe-AgI-As{sub 2}Se{sub 3} chalcogenide glasses

Energy Technology Data Exchange (ETDEWEB)

Kassem, M. [Univ Lille Nord de France, F-59000 Lille (France); ULCO, LPCA, EAC CNRS 4493 F-59140 Dunkerque (France); Le Coq, D., E-mail: david.lecoq@univ-littoral.fr [Univ Lille Nord de France, F-59000 Lille (France); ULCO, LPCA, EAC CNRS 4493 F-59140 Dunkerque (France); Fourmentin, M.; Hindle, F.; Bokova, M.; Cuisset, A.; Masselin, P.; Bychkov, E. [Univ Lille Nord de France, F-59000 Lille (France); ULCO, LPCA, EAC CNRS 4493 F-59140 Dunkerque (France)

2011-02-15

Research highlights: {yields} Determination of the glass-forming region in the pseudo-ternary CdSe-AgI-As{sub 2}Se{sub 3} system. {yields} Characterization of macroscopic properties of the new CdSe-AgI-As{sub 2}Se{sub 3} glasses. {yields} Far infrared transmission of chalcogenide glasses. {yields} Characterization of the total conductivity of CdSe-AgI-As{sub 2}Se{sub 3} glasses. -- Abstract: The glass-forming region in the pseudo-ternary CdSe-AgI-As{sub 2}Se{sub 3} system was determined. Measurements including differential scanning calorimetry (DSC), density, and X-ray diffraction were performed. The effect resulting from the addition of CdSe or AgI has been highlighted by examining three series of different base glasses. The characteristic temperatures of the glass samples, including glass transition (T{sub g}), crystallisation (T{sub x}), and melting (T{sub m}) temperatures are reported and used to calculate their {Delta}T = T{sub x} - T{sub g} and their Hruby, H{sub r} = (T{sub x} - T{sub g})/(T{sub m} - T{sub x}), criteria. Evolution of the total electrical conductivity {sigma} and the room temperature conductivity {sigma}{sub 298} was also studied. The terahertz transparency domain in the 50-600 cm{sup -1} region was pointed for different chalcogenide glasses (ChGs) and the potential of the THz spectroscopy was suggested to obtain structural information on ChGs.

Structural, morphological and magnetic analysis of Cd–Co–S dilute magnetic semiconductor nanofilms

Energy Technology Data Exchange (ETDEWEB)

Kumar, Suresh [Department of Physics and Materials Science, Jaypee University of Information Technology, Waknaghat, Solan, Himachal Pradesh 173234 (India); Negi, N.S. [Department of Physics, Himachal Pradesh University, Summer Hill, Shimla, Himachal Pradesh 171005 (India); Katyal, S.C. [Department of Physics, Jaypee Institute of Information Technology, Sec-128, Noida, Uttar Pradesh 201301 (India); Sharma, Pankaj, E-mail: pankaj.sharma@juit.ac.in [Department of Physics and Materials Science, Jaypee University of Information Technology, Waknaghat, Solan, Himachal Pradesh 173234 (India); Sharma, Vineet [Department of Physics and Materials Science, Jaypee University of Information Technology, Waknaghat, Solan, Himachal Pradesh 173234 (India)

2014-10-01

Cd{sub 1−x}Co{sub x}S dilute magnetic semiconductor nanofilms (0≤x≤0.08 at%) deposited by chemical bath deposition have been investigated using grazing angle x-ray diffraction, atomic force microscopy and vibrating sample magnetometer. The introduction of Co{sup 2+} ions in CdS structure induces structural disorders and hence, results in degradation of crystallinity. The crystallite size, interplanar spacing and lattice parameter ratio decrease with increasing Co{sup 2+} concentration in CdS. The diamagnetic state of CdS disappears with increase in Co concentration and films with x>0.02 exhibit ferromagnetism. This may be explained in terms of the spin–orbit interactions and Co{sup 2+} ion induced the lattice defects and phase separation. - Highlights: • Cd{sub 1−x}Co{sub x}S dilute magnetic semiconductor nanofilms (0≤x≤0.08 at%) deposited by CBD. • The diamagnetic state of CdS vanishes for x=0.02. • For x>0.02, dilute magnetic semiconductor nanofilms shows a ferromagnetic state.

Structure and photoelectrochemistry of silver-copper-indium-diselenide ((AgCu)InSe2) thin film

Science.gov (United States)

Zhang, Lin Rui; Li, Tong; Wang, Hao; Pang, Wei; Chen, Yi Chuan; Song, Xue Mei; Zhang, Yong Zhe; Yan, Hui

2018-02-01

In this work, silver (Ag) precursors with different thicknesses were sputtered on the surfaces of CuIn alloys, and (AgCu)InSe2 (ACIS) films were formed after selenization at 550 °C under nitrogen condition using a rapid thermal process furnace. The structure and electrical properties of the ACIS films were investigated. The result showed that the distribution of Ag+ ion was more uniform with increasing the thickness of Ag precursor, and the surface of the thin-film became more homogeneous and denser. When Ag/Cu ratio ≥0.249, the small grain particles disappeared. The band gap can be rationally controlled by adjusting Ag content. When (Ag + Cu)/In ratio ≥ 1.15, the surface of the ACIS thin-film mainly exhibited n-type semiconductor. Through the photoelectrochemistry measurement, it was observed that the incorporation of Ag+ ions could improve photocurrent by adjusting the band gap. With the Ag precursor thickness increased, the dark current decreased at the more negative potential.

Quantum Dot Sensitized Solar Cells Based on TiO2/AgInS2

Science.gov (United States)

Pawar, Sachin A.; Jeong, Jae Pil; Patil, Dipali S.; More, Vivek M.; Lee, Rochelle S.; Shin, Jae Cheol; Choi, Won Jun

2018-05-01

Quantum dot heterojunctions with type-II band alignment can efficiently separate photogenerated electron-hole pairs and, hence, are useful for solar cell studies. In this study, a quantum dot sensitized solar cell (QDSSC) made of TiO2/AgInS2 is achieved to boost the photoconversion efficiency for the TiO2-based system by varying the AgInS2 layer's thickness. The TiO2 nanorods array film is prepared by using a simple hydrothermal technique. The formation of a AgInS2 QD-sensitized TiO2-nanorod photoelectrode is carried out by successive ionic layer adsorption and reaction (SILAR) technique. The effect of the QD layer on the performance of the solar cell is studied by varying the SILAR cycles of the QD coating. The synthesized electrode materials are characterized by using X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, high resolution transmission electron microscopy and solar cell performances. The results indicate that the nanocrystals have effectively covered the outer surfaces of the TiO2 nanorods. The interfacial structure of quantum dots (QDs)/TiO2 is also investigated, and the growth interface is verified. A careful comparison between TiO2/AgInS2 sensitized cells reveals that the trasfer of electrons and hole proceeds efficiently, the recombination is suppressed for the optimum thickness of the QD layer and light from the entire visible spectrum is utilised. Under AM 1.5G illumination, a high photocurrent of 1.36 mAcm-2 with an improved power conversion efficiency of 0.48% is obtained. The solar cell properties of our photoanodes suggest that the TiO2 nanorod array films co-sensitized by AgInS2 nanoclusters have potential applications in solar cells.

Target swapping in PLD: An efficient approach for CdS/SiO2 and CdS:Ag(1%)/SiO2 nanocomposite thin films with enhanced luminescent properties

International Nuclear Information System (INIS)

Saxena, Nupur; Kumar, Pragati; Gupta, Vinay

2017-01-01

A novel synthesis method for luminescent and by-products (like CdO) free CdS/SiO 2 and CdS:Ag(1%)/SiO 2 (i.e. 1%Ag doped CdS/SiO 2 ) nanocomposite thin films at room temperature by pulsed laser deposition is reported. Targets of CdS, CdS:Ag(1%) and SiO 2 are used to deposit CdS/SiO 2 and CdS:Ag(1%)/SiO 2 nanocomposite thin films by swapping them at a frequency ratio of 2:8 laser pulses/sec. X-ray photoelectron spectroscopy analysis ensures the ratio of CdS to SiO 2 in nanocomposite as 21:79 which is nearly same as the ratio of incident pulses/sec (i.e. 2:8) on the two targets. Transmission electron micrographs visualize the formation of CdS/ CdS:Ag(1%) nanocrystals in nanocomposite systems after annealing at 500 °C. Highly intense and broad red emission is achieved from CdS/SiO 2 and CdS:Ag(1%)/SiO 2 nanocomposites. The efficiencies of emission from pristine CdS:SiO 2 and CdS:Ag(1%)/SiO 2 nanocomposites are found to be enhanced by approximately two times as compared to sole nanocrystalline CdS and CdS:Ag(1%) thin films respectively and further enhanced upto 7 times on annealing the nanocomposite systems at 500 °C. - Graphical abstract: A modified synthesis method for luminescent and by-products (like CdO) free undoped &1% Ag doped CdS/SiO 2 (deposit CdS/SiO 2 and CdS:Ag(1%)/SiO 2 ) nanocomposite thin films at room temperature by pulsed laser deposition is reported. Targets of CdS or CdS:Ag(1%) and SiO 2 are used to deposit CdS/SiO 2 and CdS:Ag(1%)/SiO 2 nanocomposite thin films by swapping them at a frequency of 2:8 pulses/sec. X-ray photoelectron spectroscopy analysis ensures the ratio of CdS to SiO 2 in nanocomposite as 21:79 which is nearly same as the ratio of incident pulses/sec (2:8) on the two targets. Transmission electron micrographs visualize the formation of CdS nanocrystals in nanocomposite systems after annealing at 500 °C. Intense and broad red emission is achieved from deposit CdS/SiO 2 and CdS:Ag(1%)/SiO 2 nanocomposites. The efficiency of

Preparation and supercapacitance performance of manganese oxide nanosheets/graphene/carbon nanotubes ternary composite film

International Nuclear Information System (INIS)

Tang, Qianqiu; Sun, Minqiang; Yu, Shuangmin; Wang, Gengchao

2014-01-01

Graphical abstract: - Highlights: • The MnO 2 nanosheets/graphene/MWCNT composite film with a porous sandwich structure was fabricated through a filtration-directed self-assembly. • The introduction of graphene and MWCNT restricts dense stacking of MnO 2 nanosheets. • Ternary composite film exhibits impressive electrochemical performance compared to pure MnO 2 nanosheets. - Abstract: A novel MnO 2 nanosheets/graphene nanosheets/carboxylic multi-walled carbon nanotubes (MONS/GNS/cMWCNT) ternary composite film was fabricated through a filtration-directed self-assembly method. The Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images showed the porous sandwiched structure of MONS/GNS/cMWCNT with GNS providing a conductive substrate and cMWCNT functioning as a vertical electron pathway. The X-ray diffraction (XRD) and Raman spectra further confirmed that the introduction of GNS and cMWCNT restricted the serious aggregation of MONS, resulting in a higher specific area (691 m 2 g −1 ). As a result, the MONS/GNS/cMWCNT composite film exhibited higher specific capacitance (248 Fg −1 at 1 Ag −1 in 1 M Na 2 SO 4 ), better rate performance (66.9% capacitance retention from 0.2 to 10 Ag −1 ) and cycling stability (86.5% retention after 3000 cycles) compared with those of pure dried MnO 2 nanosheets

Improvement of photocatalytic activities of Ag/P25 hybrid systems by controlled morphology of Ag nanoprisms

Energy Technology Data Exchange (ETDEWEB)

Lee, Ti, E-mail: r01527017@ntu.edu.tw [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Chao, Bo-Kai, E-mail: d98527007@ntu.edu.tw [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Kuo, Yu-Lin, E-mail: ylkuo@mail.ntust.edu.tw [Department of Mechanical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Hsueh, Chun-Hway, E-mail: hsuehc@ntu.edu.tw [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

2017-05-01

Constructing hybrid systems with noble metal nanostructures is one known way to improve the poor photocatalysis efficiency of TiO{sub 2} under visible light. In our study, two different Ag nanostructures were prepared: (1) Ag nanospheres synthesized by chemical reduction method, and (2) Ag nanoprisms transformed from nanospheres with an additional photo-conversion process. Both Ag-TiO{sub 2} hybrid systems were prepared by mixing various concentrations of Ag solutions with commercial TiO{sub 2} powder (P25), and they were then utilized as photocatalysts for the photodecolorization test of methyl blue under various light sources (fluorescent, UV light and red LED lamps) irradiations. Results of the photodecolorization tests showed that Ag nanostructures could evidently enhance the photocatalytic activity of TiO{sub 2} under different light sources, while an optimal composition of 0.432 wt% Ag nanoprisms/TiO{sub 2} displayed superior photocatalytic properties under visible light irradiations (fluorescent and red LED lamps). The enhanced photocatalytic activities could be mainly attributed to the mechanisms of hot electrons injection and resonant energy transfer by the localized surface plasmon resonance of Ag nanostructures and the electronic states favorable of charge separation at the interface between metals and semiconductors. - Highlights: • We used Ag nanostructures to improve photocatalysis efficiency of TiO{sub 2}. • Ag nanoprisms were more efficient than Ag nanospheres under visible light. • Ag nanoprisms/P25 is about 7 times more efficient than P25 under fluorescent lamp. • Mechanisms rely on hot electrons injection and resonant energy transfer by LSPR.

Improvement of photocatalytic activities of Ag/P25 hybrid systems by controlled morphology of Ag nanoprisms

International Nuclear Information System (INIS)

Lee, Ti; Chao, Bo-Kai; Kuo, Yu-Lin; Hsueh, Chun-Hway

2017-01-01

Constructing hybrid systems with noble metal nanostructures is one known way to improve the poor photocatalysis efficiency of TiO_2 under visible light. In our study, two different Ag nanostructures were prepared: (1) Ag nanospheres synthesized by chemical reduction method, and (2) Ag nanoprisms transformed from nanospheres with an additional photo-conversion process. Both Ag-TiO_2 hybrid systems were prepared by mixing various concentrations of Ag solutions with commercial TiO_2 powder (P25), and they were then utilized as photocatalysts for the photodecolorization test of methyl blue under various light sources (fluorescent, UV light and red LED lamps) irradiations. Results of the photodecolorization tests showed that Ag nanostructures could evidently enhance the photocatalytic activity of TiO_2 under different light sources, while an optimal composition of 0.432 wt% Ag nanoprisms/TiO_2 displayed superior photocatalytic properties under visible light irradiations (fluorescent and red LED lamps). The enhanced photocatalytic activities could be mainly attributed to the mechanisms of hot electrons injection and resonant energy transfer by the localized surface plasmon resonance of Ag nanostructures and the electronic states favorable of charge separation at the interface between metals and semiconductors. - Highlights: • We used Ag nanostructures to improve photocatalysis efficiency of TiO_2. • Ag nanoprisms were more efficient than Ag nanospheres under visible light. • Ag nanoprisms/P25 is about 7 times more efficient than P25 under fluorescent lamp. • Mechanisms rely on hot electrons injection and resonant energy transfer by LSPR.

Enhanced Visible Light Photocatalytic Degradation of Organic Pollutants over Flower-Like Bi2O2CO3 Dotted with Ag@AgBr

Directory of Open Access Journals (Sweden)

Shuanglong Lin

2016-10-01

Full Text Available A facile and feasible oil-in-water self-assembly approach was developed to synthesize flower-like Ag@AgBr/Bi2O2CO3 micro-composites. The photocatalytic activities of the samples were evaluated through methylene blue degradation under visible light irradiation. Compared to Bi2O2CO3, flower-like Ag@AgBr/Bi2O2CO3 micro-composites show enhanced photocatalytic activities. In addition, results indicate that both the physicochemical properties and associated photocatalytic activities of Ag@AgBr/Bi2O2CO3 composites are shown to be dependent on the loading quantity of Ag@AgBr. The highest photocatalytic performance was achieved at 7 wt % Ag@AgBr, degrading 95.18% methylene blue (MB after 20 min of irradiation, which is over 1.52 and 3.56 times more efficient than that of pure Ag@AgBr and pure Bi2O2CO3, respectively. Bisphenol A (BPA was also degraded to further demonstrate the degradation ability of Ag@AgBr/Bi2O2CO3. A photocatalytic mechanism for the degradation of organic compounds over Ag@AgBr/Bi2O2CO3 was proposed. Results from this study illustrate an entirely new approach to fabricate semiconductor composites containing Ag@AgX/bismuth (X = a halogen.

Influence of Ag doping concentration on structural and optical properties of CdS thin film

International Nuclear Information System (INIS)

Kumar, Pragati; Saxena, Nupur; Gupta, Vinay; Agarwal, Avinash

2015-01-01

This work shows the influence of Ag concentration on structural properties of pulsed laser deposited nanocrystalline CdS thin film. X-ray photoelectron spectroscopy (XPS) studies confirm the dopant concentration in CdS films and atomic concentration of elements. XPS studies show that the samples are slightly sulfur deficient. GAXRD scan reveals the structural phase transformation from cubic to hexagonal phase of CdS without appearance of any phase of CdO, Ag 2 O or Ag 2 S suggesting the substitutional doping of Ag ions. Photoluminescence studies illustrate that emission intensity increases with increase in dopant concentration upto 5% and then decreases for higher dopant concentration

Influence of Ag doping concentration on structural and optical properties of CdS thin film

Energy Technology Data Exchange (ETDEWEB)

Kumar, Pragati, E-mail: pkumar.phy@gmail.com [Department of Physics, Bareilly College, Bareilly, 243 005, Uttar Pradesh (India); Department of Physics and Astrophysics, University of Delhi, Delhi, 110 007 (India); Saxena, Nupur; Gupta, Vinay [Department of Physics and Astrophysics, University of Delhi, Delhi, 110 007 (India); Agarwal, Avinash [Department of Physics, Bareilly College, Bareilly, 243 005, Uttar Pradesh (India)

2015-05-15

This work shows the influence of Ag concentration on structural properties of pulsed laser deposited nanocrystalline CdS thin film. X-ray photoelectron spectroscopy (XPS) studies confirm the dopant concentration in CdS films and atomic concentration of elements. XPS studies show that the samples are slightly sulfur deficient. GAXRD scan reveals the structural phase transformation from cubic to hexagonal phase of CdS without appearance of any phase of CdO, Ag{sub 2}O or Ag{sub 2}S suggesting the substitutional doping of Ag ions. Photoluminescence studies illustrate that emission intensity increases with increase in dopant concentration upto 5% and then decreases for higher dopant concentration.