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Sample records for cadmium sulfide solar

  1. Cadmium sulfide solar cells

    NASA Technical Reports Server (NTRS)

    Stanley, A. G.

    1975-01-01

    Development, fabrication and applications of CdS solar cells are reviewed in detail. The suitability of CdS cells for large solar panels and microcircuitry, and their low cost, are emphasized. Developments are reviewed by manufacturer-developer. Vapor phase deposition of thin-film solar cells, doping and co-evaporation, sputtering, chemical spray, and sintered layers are reviewed, in addition to spray deposition, monograin layer structures, and silk screening. Formation of junctions by electroplating, evaporation, brushing, CuCl dip, and chemiplating are discussed, along with counterelectrode fabrication, VPD film structures, the Cu2S barrier layer, and various photovoltaic effects (contact photovoltage, light intensity variation, optical enhancement), and various other CdS topics.

  2. INVESTIGATION OF THIN FILM CADMIUM SULFIDE SOLAR CELLS.

    DTIC Science & Technology

    SOLAR CELLS , *CADMIUM COMPOUNDS, FILMS, SULFIDES, VAPOR PLATING, VACUUM APPARATUS, SINGLE CRYSTALS, TITANIUM, COPPER COMPOUNDS, CHLORIDES, INDIUM, MOLYBDENUM, SILICON COMPOUNDS, MONOXIDES, SURFACE PROPERTIES, ENERGY CONVERSION.

  3. Integrated thin film cadmium sulfide solar cell module

    NASA Technical Reports Server (NTRS)

    Mickelsen, R. A.; Abbott, D. D.

    1971-01-01

    The design, development, fabrication and tests of flexible integrated thin-film cadmium sulfide solar cells and modules are discussed. The development of low cost and high production rate methods for interconnecting cells into large solar arrays is described. Chromium thin films were applied extensively in the deposited cell structures as a means to: (1) achieve high adherence between the cadmium sulfide films and the vacuum-metallized copper substrates, (2) obtain an ohmic contact to the cadmium sulfide films, and (3) improve the adherence of gold films as grids or contact areas.

  4. A study of the stability of cadmium sulfide/copper sulfide and cadmium sulfide copper-indium-diselenide solar cells

    NASA Astrophysics Data System (ADS)

    Noel, G.; Richard, N.; Gaines, G.

    1984-08-01

    Groups of high efficiency cadmium sulfide/copper sulfide solar cells were exposed to combinations of stresses designed to isolate and accelerate intrinsic degradation mechanisms. Stresses included elevated temperature, illumination intensity, and cell loading conditions. All stress exposures and tests were conducted in a benign (high purity argon) atmosphere. Two primary intrinsic modes of degradation were identified: degradation of the open circuit voltage under continuous illumination and nonzero loading was found to be self recovering upon interruption of illumination or upon shorting or reverse biasing the cells. It was attributed to traps in the depletion region. Recovery from decay of light generated current was not spontaneous but could be partially accomplished by annealing in a reducing (hydrogen) environment. It was attributed to changes in the stoichiometry of the copper sulfide under the influence of electric fields and currents.

  5. Simulated space environment tests on cadmium sulfide solar cells

    NASA Technical Reports Server (NTRS)

    Clarke, D. R.; Oman, H.

    1971-01-01

    Cadmium sulfide (Cu2s - CdS) solar cells were tested under simulated space environmental conditions. Some cells were thermally cycled with illumination from a Xenon-arc solar simulator. A cycle was one hour of illumination followed immediately with one-half hour of darkness. In the light, the cells reached an equilibrium temperature of 60 C (333 K) and in the dark the cell temperature dropped to -120 C (153 K). Other cells were constantly illuminated with a Xenon-arc solar simulator. The equilibrium temperature of these cells was 55 C (328 K). The black vacuum chamber walls were cooled with liquid nitrogen to simulate a space heat sink. Chamber pressure was maintained at 0.000001 torr or less. Almost all of the solar cells tested degraded in power when exposed to a simulated space environment of either thermal cycling or constant illumination. The cells tested the longest were exposed to 10.050 thermal cycles.

  6. One-Dimensional Fast Transient Simulator for Modeling Cadmium Sulfide/Cadmium Telluride Solar Cells

    NASA Astrophysics Data System (ADS)

    Guo, Da

    Solar energy, including solar heating, solar architecture, solar thermal electricity and solar photovoltaics, is one of the primary alternative energy sources to fossil fuel. Being one of the most important techniques, significant research has been conducted in solar cell efficiency improvement. Simulation of various structures and materials of solar cells provides a deeper understanding of device operation and ways to improve their efficiency. Over the last two decades, polycrystalline thin-film Cadmium-Sulfide and Cadmium-Telluride (CdS/CdTe) solar cells fabricated on glass substrates have been considered as one of the most promising candidate in the photovoltaic technologies, for their similar efficiency and low costs when compared to traditional silicon-based solar cells. In this work a fast one dimensional time-dependent/steady-state drift-diffusion simulator, accelerated by adaptive non-uniform mesh and automatic time-step control, for modeling solar cells has been developed and has been used to simulate a CdS/CdTe solar cell. These models are used to reproduce transients of carrier transport in response to step-function signals of different bias and varied light intensity. The time-step control models are also used to help convergence in steady-state simulations where constrained material constants, such as carrier lifetimes in the order of nanosecond and carrier mobility in the order of 100 cm2/Vs, must be applied.

  7. Cadmium sulfide membranes

    DOEpatents

    Spanhel, Lubomir; Anderson, Marc A.

    1992-07-07

    A method is described for the creation of novel q-effect cadmium sulfide membranes. The membranes are made by first creating a dilute cadmium sulfide colloid in aqueous suspension and then removing the water and excess salts therefrom. The cadmium sulfide membrane thus produced is luminescent at room temperature and may have application in laser fabrication.

  8. Cadmium sulfide membranes

    DOEpatents

    Spanhel, Lubomir; Anderson, Marc A.

    1991-10-22

    A method is described for the creation of novel q-effect cadmium sulfide membranes. The membranes are made by first creating a dilute cadmium sulfide colloid in aqueous suspension and then removing the water and excess salts therefrom. The cadmium sulfide membrane thus produced is luminescent at room temperature and may have application in laser fabrication.

  9. Cadmium sulfide thin films deposited by close spaced sublimation and cadmium sulfide/cadmium telluride solar cells

    NASA Astrophysics Data System (ADS)

    Marinskiy, Dmitriy Nikolaevich

    1998-12-01

    One of the applications of CdS films is as a window layer in CdTe and Cu(In,Ga)Sesb2 solar cells. The study of the optical and structural properties of CdS films deposited by close spaced sublimation as well as their influence on CdS/CdTe solar cell performance is part of the CdTe solar cell program at the University of South Florida. CdS films have been deposited by the close-spaced sublimation technique. The influence of the main process parameters, the substrate and source temperatures, and the ambient in the deposition chamber has been investigated. As-deposited films have been subjected to heat treatments in Hsb2 ambient, in CdClsb2 atmosphere, and in atmosphere with small amounts of oxygen. A special annealing chamber was built to carry out the annealing experiments in the presence of CdClsb2 vapor and oxygen. Several CSS chambers were assembled to study the influence of various process parameters simultaneously and validate the results. Results of scanning electron microscopy and photoluminescence measurements have been used as the primary characterization techniques. X-ray diffraction, electron microprobe analysis, and transmission measurements have also been carried out. It was found that as deposited CdS films have a hexagonal structure independent of the process parameters used. The presence of a CdO phase was detected in the samples grown with the highest oxygen concentration in the ambient. The resistivity of CdS films is controlled by intergrain barriers. Photoluminescence measurements showed the presence of oxygen-acceptor transition and a wide variation in the intensity of deep emission bands. The variation in the intensities was correlated with the variation in the deposition and annealing conditions. However, no correlation was found between the PL intensities of defect bands and cell performance. CdS/CdTe junctions have been fabricated using standard deposition and postgrowth techniques developed in the USF solar cells laboratory. All cells have

  10. Method of epitaxially depositing cadmium sulfide

    NASA Technical Reports Server (NTRS)

    Hawrylo, Frank Z. (Inventor)

    1980-01-01

    A single crystal layer of either cadmium sulfide or an alloy of cadmium sulfide and indium phosphide is epitaxially deposited on a substrate of cadmium sulfide by liquid phase epitaxy using indium as the solvent.

  11. Process for producing cadmium sulfide on a cadmium telluride surface

    DOEpatents

    Levi, Dean H.; Nelson, Art J.; Ahrenkiel, Richard K.

    1996-01-01

    A process for producing a layer of cadmium sulfide on a cadmium telluride surface to be employed in a photovoltaic device. The process comprises providing a cadmium telluride surface which is exposed to a hydrogen sulfide plasma at an exposure flow rate, an exposure time and an exposure temperature sufficient to permit reaction between the hydrogen sulfide and cadmium telluride to thereby form a cadmium sulfide layer on the cadmium telluride surface and accomplish passivation. In addition to passivation, a heterojunction at the interface of the cadmium sulfide and the cadmium telluride can be formed when the layer of cadmium sulfide formed on the cadmium telluride is of sufficient thickness.

  12. From front contact to back contact in cadmium telluride/cadmium sulfide solar cells: Buffer layer and interfacial layer

    NASA Astrophysics Data System (ADS)

    Roussillon, Yann

    Cadmium telluride (CdTe) polycrystalline thin film solar cells, with their near optimum direct band-gap of 1.4 eV matching almost perfectly the sun radiation spectrum, are a strong contender as a less expensive alternative, among photovoltaic materials, than the more commonly used silicon-based cells. Polycrystalline solar cells are usually deposited over large areas. Such devices often exhibit strong fluctuations (nonuniformities) in electronic properties, which originate from deposition and post-deposition processes, and are detrimental to the device performance. Therefore their effects need to be constrained. A new approach in this work was, when a CdS/CdTe solar cell is exposed to light and immersed in a proper electrolyte, fluctuations in surface potential can drive electrochemical reactions which result in a nonuniform interfacial layer that could balance the original nonuniformity. This approach improved the device efficiency for CdS/CdTe photovoltaic devices from 1--3% to 11--12%. Cadmium sulfide (CdS), used as a window layer and heterojunction partner to CdTe, is electrically inactive and absorb light energies above its band-gap of 2.4 eV. Therefore, to maximize the device efficiency, a thin US layer needs to be used. However, more defects, such as pinholes, are likely to be present in the film, leading to shunts. A resistive transparent layer, called buffer layer, is therefore deposited before CdS. A key observation was that the open-circuit voltage (Voc) for cells made using a buffer layer was high, around 800 mV, similar to cells without buffer layer after Cu doping. The standard p-n junction theory cannot explain this phenomena, therefore an alternative junction mechanism, similar to metal-insulator-semiconductor devices, was developed. Furthermore, alternative Cu-free back-contacts were used in conjunction with a buffer layer. The Voc of the devices was found to be dependent of the back contact used. This change occurs as the back-contact junction

  13. Development of copper sulfide/cadmium sulfide thin-film solar cells

    SciTech Connect

    Szedon, J. R.; Biter, W. J.; Dickey, H. C.

    1982-03-08

    The most important accomplishments during this period were to demonstrate and to elucidate further the complex effects that occur during the aging of Cu/sub 2/S/CdS thin-film solar cells in flowing wet oxygen. There are two distinct effects. At constant illumination, the short-circuit current of cells aged at room temperature consistently decreases with time. The second effect, related to diode opposing current, is more involved and may result from several competing mechanisms. Over the short term (approx. 4 to 5 hours), the magnitude of diode opposing current decreases. After approx. 20 hours of aging, opposing current generally returns to the level achieved after hydrogen annealing which immediately preceded the aging sequence. Optical measurements of the spectral transmission of the Cu/sub 2/S layers in a cell content have been made using a silicon detector epoxied to the back of a CdS cell after the copper foil substrate was removed. There is no significant change in Cu/sub 2/S transmission behavior for wavelengths ranging from 525 to 1000 nm during wet-oxygen aging for periods of 2 to 36 hours. This suggests that the decrease in J/sub SC/ at constant illumination, for the aging experiments in a flowing wet-oxygen ambient, arises because of changes in minority-carrier transport properties of the Cu/sub 2/S. Before developing a method for using an epoxied silicon detector to measure optical behavior of the Cu/sub 2/S layer, we explored the possibility of using a junction-containing wafer of silicon as a substrate for deposited CdS films. Some monolithic structures were successfully fabricated. Comparisons were made of CdS grain structure details in the junction detector area and in an adjacent metallized area.

  14. Development of copper sulfide/cadmium sulfide thin-film solar cells

    SciTech Connect

    Szedon, J.R.; Biter, W.J.; Abel, J.A.; Dickey, H.C.; Shirland, F.A.

    1981-02-27

    The purpose of this work has been to identify aspects of cell fabrication and treatment which are critical for achieving high efficiency Cu/sub 2/S/CdS solar cells. In approaching the problem several comparisons were made of the effects of specific steps in two methods of cell fabrication. These methods had previously given cells of about 6% and a maximum of 9% efficiency. Three areas requiring special attention and specific means to achieve acceptable results were identified. (1) The Cu/sub 2/S/CdS heterojunction area must be minimized. If single source evaporations of CdS are made on substrates whose temperatures (approx. 220/sup 0/C) are monitored and controlled using welded thermocouples, the CdS films will have adequately large grains (grain diameter greater than or equal to 2 ..mu..m) and will not develop significant etch pits during texturing in a mild etchant solution. (2) The termination of the wet barrier processing steps must be done carefully. An acceptable termination involves minimizing the amount of cuprous chloride retained on the cell surface during transfer to a rinsing stage while providing adequate exclusion of air from the space above the surface of the cuprous chloride solution. (3) Once formed, the Cu/sub 2/S layer should not be exposed to high temperatures (>100/sup 0/C) for long periods of time (> 5 min) if surface adsorbed moisture or oxygen are present. Heat treatments in ampoules under flowing hydrogen atmospheres should be preceded and followed by periods of at least 30 minutes at room temperature in the reducing ambient. If all these precautions are taken, wet chemical barrier processing of thermally evaporated CdS films on zinc-plated copper foil substrates yields cells of nearly 8% conversion efficiency without AR coating.

  15. Electrical Properties of Polycrystalline Cadmium Sulfide Films Produced by Laser-Driven Physical Vapor Deposition for Cadmium Sulfide/cadmium Telluride Solar Cells

    NASA Astrophysics Data System (ADS)

    Tsien, Li-Hua

    1992-01-01

    Electrical conductivity, carrier density, and mobilities have been measured for CdS films grown on glass substrates by laser-driven physical vapor deposition (LDPVD). This work was part of an overall effort to gain a better understanding of the processes that are important in determining the efficiency of CdTe-based thin film solar cells. Films were grown from several target materials including pure CdS, CdS doped with indium, and CdS mixed with cadmium chloride. Some films were also subjected to post-growth chemical and thermal treatments. Generally, grain boundary effects dominate the mobility between 80K and 350K. The data is interpreted using a model for polycrystalline and powdered semiconductors which was developed by Orton and Powell (J. S. Orton and M. J. Powell, Rep. Prog. Phys. 43, 81 (1980)) and is discussed using the concept of effective doping levels.

  16. Stability studies of cadmium telluride/cadmium sulfide thin film solar cells

    NASA Astrophysics Data System (ADS)

    Tetali, Bhaskar Reddy

    CdTe/CdS solar cells have shown great potential for terrestrial solar power applications. To be commercially viable they need to operate efficiently for about 30 years. CdS/CdTe solar cells fabricated at USF have shown record efficiencies upto 16.5% [46]. This research involves the study of thermal stress (TS) and light soaking (LS) on the stability of high efficiency (>10%) solar cells. The change in key electrical parameters Voc, FF, J sc, A and Jo are quantified for more than 2000 hours of stressing. The device degradation was found to increase with stress temperature for TS. Below 100°C, the changes were due to collection and recombination losses. Above 100°C, "shunting" mechanisms were found to start affecting the device performance. A fast drop in performance within the first 500 hours was observed. It is believed to be due to an increase in deep-level Cu-related defects that increase with stress temperature. Diffusion of Cu i+ ions from the back contact along CdTe grain boundaries had been previously reported [16]. An increase in light/dark J-V crossover and bulk Rs with stress time and temperature was observed. A slow degradation component attributed to Cu-related substitutional defect [23] formation/diffusion to the junction and CdS is proposed. This should compensate the CdS over time and increase its photoconductivity/resistivity. An improvement in the current collection and FF within 100 hours of LS was observed. This is possibly due to the enhancement of Cui + diffusion into the junction and CdS during LS as previously reported [16]. A reduction in light/dark J-V crossover was observed, possibly due to an increase in CdS doping and reduction in the CdS/SnO2 front contact barrier. However, a fast decrease in Voc and increase in recombination current was also observed in the first 1000 hours of LS. This is possibly due to the existence of higher concentration of Cu-related deep level defects at the junction. A larger decrease in Voc was found for LS

  17. Process for producing cadmium sulfide on a cadmium telluride surface

    DOEpatents

    Levi, D.H.; Nelson, A.J.; Ahrenkiel, R.K.

    1996-07-30

    A process is described for producing a layer of cadmium sulfide on a cadmium telluride surface to be employed in a photovoltaic device. The process comprises providing a cadmium telluride surface which is exposed to a hydrogen sulfide plasma at an exposure flow rate, an exposure time and an exposure temperature sufficient to permit reaction between the hydrogen sulfide and cadmium telluride to thereby form a cadmium sulfide layer on the cadmium telluride surface and accomplish passivation. In addition to passivation, a heterojunction at the interface of the cadmium sulfide and the cadmium telluride can be formed when the layer of cadmium sulfide formed on the cadmium telluride is of sufficient thickness. 12 figs.

  18. Infrared birefringence spectra for cadmium sulfide and cadmium selenide.

    PubMed

    Chenault, D B; Chipman, R A

    1993-08-01

    Measurements of the birefringence spectra for cadmium sulfide and cadmium selenide from 2.5 to 16.5µm obtained with a rotating sample spectropolarimeter are presented. Because of the similarity in the birefringence spectra for cadmium sulfide and cadmium selenide, a highly achromatic IR retarder can be constructed from a combination of these materials. The ordinary and extraordinary refractive indices for cadmium sulfide are estimated in the region from 10.6 to 15 µm and for cadmium selenide from 10.6 to 16.5 µm by combining these birefringence data with an extrapolation of previous dispersion relations.

  19. The Triboluminescence of Zinc Cadmium Sulfide

    DTIC Science & Technology

    1978-11-01

    W£rA0fe4 5^5 /KD-AtW Sis TECHNICAL REPORT ARBRL-TR-02124 THE TRIBOLUMINESCENCE OF ZINC CADMIUM SULFIDE Carmen M. Cialella TECHNICAL James...THE TRIBOLUMINESCENCE OF ZINC CADMIUM SULFIDE READ INSTRUCTIONS BEFORE COMPLETING FORM 3. RECIPIENT’S CATALOG NUMBER 5. TYPE OF REPORT & PERIOD...and tested. This report presents subsequent efforts to determine the light output of the TL phosphor. Zinc Cadmium Sulfide (ZnCdS] as a function of

  20. Evolution of oxygenated cadmium sulfide (CdS:O) during high-temperature CdTe solar cell fabrication

    SciTech Connect

    Meysing, Daniel M.; Reese, Matthew O.; Warren, Charles W.; Abbas, Ali; Burst, James M.; Mahabaduge, Hasitha P.; Metzger, Wyatt K.; Walls, John M.; Lonergan, Mark C.; Barnes, Teresa M.; Wolden, Colin A.

    2016-12-01

    Oxygenated cadmium sulfide (CdS:O) produced by reactive sputtering has emerged as a promising alternative to conventional CdS for use as the n-type window layer in CdTe solar cells. Here, complementary techniques are used to expose the window layer (CdS or CdS:O) in completed superstrate devices and combined with a suite of materials characterization to elucidate its evolution during high temperature device processing. During device fabrication amorphous CdS:O undergoes significant interdiffusion with CdTe and recrystallization, forming CdS1-yTey nanocrystals whose Te fraction approaches solubility limits. Significant oxygen remains after processing, concentrated in sulfate clusters dispersed among the CdS1-yTey alloy phase, accounting for ~30% of the post-processed window layer based on cross-sectional microscopy. Interdiffusion and recrystallization are observed in devices with un-oxygenated CdS, but to a much lesser extent. Etching experiments suggest that the CdS thickness is minimally changed during processing, but the CdS:O window layer is reduced from 100 nm to 60-80 nm, which is confirmed by microscopy. Alloying reduces the band gap of the CdS:O window layer to 2.15 eV, but reductions in thickness and areal density improve its transmission spectrum, which is well matched to device quantum efficiency. The changes to the window layer in the reactive environments of device fabrication are profoundly different than what occurs by thermal annealing in an inert environment, which produced films with a band gap of 2.4 eV for both CdS and CdS:O. These results illustrate for the first time the significant changes that occur to the window layer during processing that are critical to the performance of CdTe solar cells.

  1. Effect of load voltage on thin film cuprous sulfide: Cadmium sulfide solar cells thermally cycled in a simulated space environment

    NASA Technical Reports Server (NTRS)

    Smithrick, J. J.; Thomas, R. D.

    1971-01-01

    Thin-film Cu2S-CdS solar cells, loaded at various fixed values of load resistance, were thermally cycled for 1429 cycles in a simulated space environment. Cell performance was measured under controlled conditions in air before and after thermal cycling. These data were used to determine the effect of load voltage on cell performance. The performance of the cells was relatively independent of load voltage up to about 0.39 volt. This appears to be a threshold voltage, beyond which there was a significant loss in cell performance. Fortunately, this threshold voltage appears to be sufficiently higher than the maximum power voltage of 0.33 volt so that it can be avoided in most applications.

  2. Cadmium stannate selective optical films for solar energy applications

    NASA Technical Reports Server (NTRS)

    Haacke, G.

    1975-01-01

    Efforts concentrated on reducing the electrical sheet resistance of sputtered cadmium stannate films, installing and testing equipment for spray coating experiments, and sputter deposition of thin cadmium sulfide layers onto cadmium stannate electrodes. In addition, single crystal silicon wafers were coated with cadmium stannate. Work also continued on the development of the backwall CdS solar cell.

  3. Impact of back-contact materials on performance and stability of cadmium sulfide/cadmium telluride solar cells

    NASA Astrophysics Data System (ADS)

    Demtsu, Samuel H.

    Thin-film CdTe based solar cells are one of the leading contenders for providing lowcost and pollution-free energy, The formation of a stable, low resistance, non-rectifying contact to p-CdTe thin-film is one of the major and critical challenges associated with this technology in the fabrication of efficient and stable solar cells. The premise of this thesis is a systematic study of the impact of back-contact materials on the initial performance and the degradation of CdS/CdTe solar cells. Two different back-contact structures that incorporate Cu as a key element are investigated in this study: (a) Cu1.4Te:HgTe-doped graphite and (b) evaporated-Cu back contacts. The effect of Cu inclusion is not limited to the back-contact layer where it is deposited. Cu is a known fast diffuser in p-CdTe, and therefore, a significant amount of Cu reaches both the CdTe and US layers. Hence, the effect of the presence of Cu on the individual layers: back-contact, the absorber (CdTe), and the window (CdS) layers is discussed respectively. The effect of different metals used to form the current-carrying electrode following the Cu layer is also evaluated. Devices are studied through current-voltage (JV) measurements at different temperatures and intensities, quantum efficiency (QE) measurements under light and voltage bias, capacitance-voltage (CV), drive-level-capacitance-profiling (DLCP), and time-resolved photoluminescence (TRPL) measurements. Numerical simulation is also used to reproduce and explain some of the experimental results. In devices made without Cu, a current-limiting effect, rollover (distortion) in the current-voltage characteristic, was observed. With the inclusion of a small amount of Cu (5-nm), however, the distortion disappeared, and higher FF was obtained. The performance of these devices was comparable to devices made with the standard Cu-doped graphite paste contacts when the same CdTe absorber is used. Small amount of Cu (5-20 nm) partially diffused into the

  4. Development of Polyaniline Using Electrochemical Technique for Plugging Pinholes in Cadmium Sulfide/Cadmium Telluride Solar Cells

    NASA Astrophysics Data System (ADS)

    Abdul-Manaf, N. A.; Echendu, O. K.; Fauzi, F.; Bowen, L.; Dharmadasa, I. M.

    2014-11-01

    Polyaniline (PAni) thin films were prepared by using an electrochemical polymerization technique on glass/FTO substrates by varying the deposition potential, deposition time, pH concentrations and heat treatment conditions. The structural, morphological, optical and electrical properties of electrodeposited PAni films were characterized using x-ray diffraction, scanning electron microscopy, UV-VIS spectroscopy, optical profilometry and D.C. conductivity measurements. Structural analysis shows the formation of the highest crystallinity for PAni thin film grown at V g 1654 mV. Optical absorption measurements have demonstrated a wide variety of energy band gaps ( E g), varying from ˜0.50 eV to 2.40 eV for PAni grown by tuning the pH value during the deposition. The electrical resistivity showed an increase from 0.37 × 106 Ω cm to 3.91 × 106 Ω cm when the pH increased from 2.00 to 6.50. The diode structures of glass/FTO/CdS/CdTe/PAni/Au were fabricated incorporating PAni as a pinhole plugging layer, and assessed for their photovoltaic activities. The results showed the enhancement of all device parameters, especially of open circuit voltage and fill factors. This improvement offers a great potential for enhancing solar cell performance and the device lifetime, and the latest results are presented in this paper.

  5. Effects of contact-based non-uniformities in cadmium sulfide/cadmium telluride thin-film solar cells

    NASA Astrophysics Data System (ADS)

    Davies, Alan R.

    To strongly contribute to the near-term electricity supply, CdTe-based photovoltaic devices must continue to improve in performance under the constraint of simple and cost efficient fabrication methods. This dissertation focuses on characterization and modeling of devices with non-uniform performance induced by the cell contacts. Devices were obtained from a commercially viable pilot-scale fabrication system at Colorado State University. Current versus voltage (J-V), quantum efficiency (QE) and laser-beam-induced current (LBIC) were the main characterization techniques applied in this work. The p-type CdTe semiconductor has a large work-function and thus tends to form a Schottky barrier when the back-electrode is formed. A common strategy of mitigating the performance-limiting contact barrier is to prepare the CdTe surface with a chemical etch, and include Cu to reduce the effective barrier. Non-uniformity of the etch or Cu inclusion, or insufficient application of Cu can result in a non-uniform contact, with regions of high- and low-energy Schottky barriers participating in the cell performance. Barrier non-uniformities in devices with little or no Cu were identified with the LBIC measurement and a model for their influence was developed and tested using PSpice circuit modeling software. Because of their superstrate configuration, CdTe cells feature front contacts made from transparent-conducting oxides (TCOs). Fluorine-doped tin oxide (F:SnO2) is a common choice because of its availability and acceptable optical and electrical properties. When the n-CdS layer of the CdS/CdTe structure is thinned to encourage greater current generation, non-uniformities of the solar cell junction arise, as CdTe comes into sporadic contact with the TCO layer. Device simulations suggest that the SnO2/CdTe junction is weaker than CdS/CdTe because of a large conduction-band offset induced by the differing electron affinities in the heterojunction. LBIC was used to verify increasing

  6. Chemical spray pyrolysis of copper indium diselenide/cadmium sulfide solar cells

    SciTech Connect

    Brown, B.J.

    1989-01-01

    This dissertation concentrates on Chemical Spray Pyrolysis (CSP) of CuInSe{sub 2} and CdS thin films and solar cells. The primary goal is to gain an understanding of the chemistry and physics of CSP, and apply this knowledge to the fabrication of CuInSe{sub 2}/CdS solar cells. It provide an extensive review of the literature on the properties of CuInSe{sub 2} an CdS produced by CSP and other techniques. The films are characterized by x-ray diffractometry, scanning electron microscopy, electron microprobe, van der Pauw-Hall measurements, and optical absorption spectroscopy, and the devices are characterized electrically in the dark and under illumination. A model for the chemical mechanisms involved in CSP of CdS an CuInSe{sub 2} thin films is developed which is used to point out similarities between the two systems and explain the correlation between spray solution pH and second phases in CuInSe{sub 2} thin films. Structural investigations show that the CuInSe{sub 2} films can be produced in either the ordered or disordered crystal structure, while different substrates radically change the morphology of the films. By taking into account the effect of second phases, the electrical and optical properties of the sprayed films agree with published results for CuInSe{sub 2} produced by other techniques. The properties of the sprayed CdS films in this work are shown to agree with those sprayed by others. The device properties of cells fabricated in both the backwall and reverse backwall configuration are compared with each other and related to the materials properties of the semiconductor layers. The highest efficiency cell employing sprayed CuInSe{sub 2} is reported; however, the efficiency of the cells still need improvement before becoming practical. The dissertation concludes with recommendations for increasing the efficiency of completely sprayed CuInSe{sub 2}/CdS solar cells.

  7. SINGLE CRYSTAL CADMIUM SULFIDE AND CADMIUM SELENIDE INSULATED-GATE FIELD-EFFECT TRIODES.

    DTIC Science & Technology

    Insulated-gate field-effect triodes were fabricated on single crystal cadmium sulfide and cadmium selenide . Both bulk crystals and platelets were...used for single crystal samples. Chromium and aluminum were found to make low impedance contacts to cadmium sulfide and cadmium selenide . The...polycrystalline cadmium sulfide and cadmium selenide IGFET’s. The characteristics of the fabricated devices were unstable with respect to time and temperature

  8. Photoluminescence study of copper-doped cadmium-telluride and related stability issues for cadmium-sulfide/cadmium-telluride solar-cell devices

    NASA Astrophysics Data System (ADS)

    Grecu, Dan S.

    Lifetime predictions for CdTe photovoltaic modules represent a complex problem, partly due to the fact that a fundamental understanding of the CdTe material properties and device operation is far from being complete. One of the stability issues actively investigated is the use of Cu for the formation of a back contact. Cu is one of the few good p-dopants for CdTe, which, by forming a p+ layer at the surface of the CdTe, relaxes the requirement for a high work function metal at the back contact. On the other hand, it is known that Cu is a fast diffuser in CdTe and it was suggested that Cu migration within the device could lead to some of the observed degradation effects. in this work, we explore Cu states and migration effects in CdTe and CdS/CdTe devices using photoluminescence (PL) as the main investigative method. We confirm the assignment of several Cu-related PL transitions observed in the CdTe spectrum, namely, a bound exciton transition (X, CUCd) at 1.59eV and a donor-acceptor pair (DAP) (D, CuCd) at 1.45eV. In addition, we observe and characterize new effects related to Cu diffusion in CdTe: (a) the quenching of a DAP, Cd-vacancy related band, at 1.55eV, and (b) the formation of a new strong lattice-coupled transition at 1.555eV. These effects, we suggest, are consistent with Cu atoms occupying substitutional positions on the Cd sublattice and/or forming Frenkel pairs of the type CUi-VCd- with Cd vacancies. Similar spectral characteristics are observed for the low-S-content CdS-CdTe alloy existent in the vicinity of the junction in solar-cell devices. Using Cu-induced changes in the PL spectrum, we propose that Cu diffuses rapidly through an interstitial mechanism, as a positively charged ion, throughout the CdTe and possibly the CdS layer during the back-contact fabrication procedure. Applied electrical fields can reverse the direction of Cu migration leading to device performance degradation. In addition, it was found that Cu-doped CdTe samples exhibit a

  9. Properties of reactively sputtered oxygenated cadmium sulfide (CdS:O) and their impact on CdTe solar cell performance

    SciTech Connect

    Meysing, Daniel M. Wolden, Colin A.; Griffith, Michelle M.; Mahabaduge, Hasitha; Pankow, Joel; Reese, Matthew O.; Burst, James M.; Rance, William L.; Barnes, Teresa M.

    2015-03-15

    Oxygenated cadmium sulfide (CdS:O) is commonly used as the n-type window layer in high-performance CdTe heterojunction solar cells. This layer is deposited by reactive sputtering, but the optimal amount of oxygen in the sputtering ambient is highly dependent on the specific system and process employed. In this work, the intrinsic properties of CdS:O were measured as a function of the oxygen content (0%–10%) in the sputtering ambient and correlated to device performance with the goal of better defining optimal CdS:O properties for CdTe solar cells. Optimal performance was found using CdS:O films that contained ∼40 at. % oxygen as measured by Rutherford backscattering spectrometry. X-ray photoelectron spectroscopy confirmed these results and showed that oxygen is incorporated primarily as oxygenated sulfur compounds (SO{sub x}). Device efficiency improved from 10.5% using CdS to >14% with CdS:O due largely to increases in short-circuit current density as well as a modest improvement in open-circuit voltage. The transparency of the CdS:O films was well correlated with observed improvements in blue quantum efficiency with increasing oxygen content. The optical bandgap of as-deposited CdS:O was identified as a simple metric for process optimization and transfer, with 2.8 eV being ideal for the device architecture employed.

  10. Process for thin film deposition of cadmium sulfide

    DOEpatents

    Muruska, H. Paul; Sansregret, Joseph L.; Young, Archie R.

    1982-01-01

    The present invention teaches a process for depositing layers of cadmium sulfide. The process includes depositing a layer of cadmium oxide by spray pyrolysis of a cadmium salt in an aqueous or organic solvent. The oxide film is then converted into cadmium sulfide by thermal ion exchange of the O.sup.-2 for S.sup.-2 by annealing the oxide layer in gaseous sulfur at elevated temperatures.

  11. Trichosporon jirovecii-mediated synthesis of cadmium sulfide nanoparticles.

    PubMed

    El-Baz, Ashraf Farag; Sorour, Noha Mohamed; Shetaia, Youssria Mohamed

    2016-05-01

    Cadmium sulphide is one of the most promising materials for solar cells and of great interest due to its useful applications in photonics and electronics, thus the development of bio-mediated synthesis of cadmium sulphide nanoparticles (CdS NPs) is one of the essential areas in nanoparticles. The present study demonstrates for the first time the eco-friendly biosynthesis of CdS NPs using the yeast Trichosporon jirovecii. The biosynthesis of CdS NPs were confirmed by UV-Vis spectrum and characterized by X-ray diffraction assay and electron microscopy. Scanning and transmission electron microscope analyses shows the formation of spherical CdS NPs with a size range of about 6-15 nm with a mean Cd:S molar ratio of 1.0:0.98. T. jirovecii produced hydrogen sulfide on cysteine containing medium confirmed by positive cysteine-desulfhydrase activity and the colony color turned yellow on 0.1 mM cadmium containing medium. T. jirovecii tolerance to cadmium was increased by the UV treatment and three 0.6 mM cadmium tolerant mutants were generated upon the UV radiation treatment. The overall results indicated that T. jirovecii could tolerate cadmium toxicity by its conversion into CdS NPs on cysteine containing medium using cysteine-desulfhydrase as a defense response mechanism. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Cadmium sulphide solar cell

    SciTech Connect

    Bassett, P.J.; Verheijen, A.W.

    1984-07-31

    The invention relates to the manufacture of cadmium sulphide solar cells. A cell is formed of a glass substrate 10, a front contact 12 made, for example, of tin oxide, a cadmium sulphide layer 14 and a copper sulphide layer 16, the junction between the layers 14 and 16 is photovoltaic. In order to form a rear contact 18 on the copper sulphide layer, the invention proposes vapor depositing a mixed layer of copper and copper oxide onto the sulphide layer. The invention also describes a method of heat treatment following the formation of the rear contact in order to optimise the electrical performance of the cell.

  13. Cadmium zinc sulfide by solution growth

    DOEpatents

    Chen, Wen S.

    1992-05-12

    A process for depositing thin layers of a II-VI compound cadmium zinc sulfide (CdZnS) by an aqueous solution growth technique with quality suitable for high efficiency photovoltaic or other devices which can benefit from the band edge shift resulting from the inclusion of Zn in the sulfide. A first solution comprising CdCl.sub.2 2.5H.sub.2 O, NH.sub.4 Cl, NH.sub.4 OH and ZnCl.sub.2, and a second solution comprising thiourea ((NH.sub.2).sub.2 CS) are combined and placed in a deposition cell, along with a substrate to form a thin i.e. 10 nm film of CdZnS on the substrate. This process can be sequentially repeated with to achieve deposition of independent multiple layers having different Zn concentrations.

  14. Impurity Studies in Single Crystal Cadmium Sulfide.

    DTIC Science & Technology

    1979-12-01

    widths and relative intensities carried out. While studying the exciton emission from pure cadmium sulfide at low temper- atures, Bliel and Broser ...A Ŗ ® tor ® i* or® 0 I jourt! 45 . leeOialdl Split ting Diatitdnl for lon i :d Donor in Cadmni um Sul1$idte AFML-TR-79-4104 B9-19-72(b) H I c CdS...Chem. Phys. 29, 1375 (1958). 4. C. E. Bleil and 1. Broser , Proceedings of the Seventh International Conference on the Physics of Semiconductors

  15. Optimization of chemical bath deposited cadmium sulfide thin films

    SciTech Connect

    Oladeji, I.O.; Chow, L.

    1997-07-01

    Cadmium sulfide (CdS) is known to be an excellent heterojunction partner of p-type cadmium telluride (CdTe) or p-type copper indium diselenide (CuInSe{sub 2}) due essentially to its high electron affinity. It is widely used as a window material in high efficiency thin-film solar cells based on CdTe or CuInSe{sub 2} owing to its transparency and photoconductivity among other properties. The authors report the optimization of CdS thin film grown by chemical bath deposition where homogeneous reactions are minimized. The optimum parameters have enabled them to maximize the thickness of the deposited film in a single dip and to grow thicker films by periodically replenishing the concentration of reactants while the substrate remains continuously dipped in the reaction bath. Characterization results reveal the deposited CdS films exhibit improved optical and electrical properties.

  16. Preparation of mesoporous cadmium sulfide nanoparticles with moderate pore size

    SciTech Connect

    Han Zhaohui Zhu, Huaiyong; Shi, Jeffrey; Parkinson, Gordon; Lu, G.Q.

    2007-03-15

    The preparation of cadmium sulfide nanoparticles that have a moderate pore size is reported. This preparation method involves a hydrothermal process that produces a precursor mixture and a following acid treatment of the precursor to get the porous material. The majority of the particles have a pore size close to 20nm, which complements and fills in the gap between the existing cadmium sulfide materials, which usually have a pore size either less than 10nm or are well above 100nm.

  17. Cadmium sulfide nanowires for the window semiconductor layer in thin film CdS-CdTe solar cells.

    PubMed

    Liu, Piao; Singh, Vijay P; Jarro, Carlos A; Rajaputra, Suresh

    2011-04-08

    Thin film CdS/CdTe heterojunction device is a leading technology for the solar cells of the next generation. We report on two novel device configurations for these cells where the traditional CdS window layer is replaced by nanowires (NW) of CdS, embedded in an aluminum oxide matrix or free-standing. An estimated 26.8% improvement in power conversion efficiency over the traditional device structure is expected, primarily because of the enhanced spectral transmission of sunlight through the NW-CdS layer and a reduction in the junction area/optical area ratio. In initial experiments, nanostructured devices of the two designs were fabricated and a power conversion efficiency value of 6.5% was achieved.

  18. Cobalt-doped cadmium sulfide nanoparticles as efficient strategy to enhance performance of quantum dot sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Firoozi, Najmeh; Dehghani, Hossein; Afrooz, Malihe

    2015-03-01

    In this study, we investigate the effect of Co2+ ion incorporation into CdS layer on the photovoltaic performance of quantum dot sensitized solar cell (QDSSC). Quantum dots are deposited by the successive ionic layer adsorption and reaction (SILAR) method on the mesoporous TiO2 film. The doped system modifies the structure of photoanode that leads to an increase in short circuit current density (Jsc) from 13.16 mA cm-2 to 16.6 mA cm-2 in the un-doped system. Electrochemical impedance analysis (EIS) reveals a decrease in charge transfer resistance at the TiO2/QDs/electrolyte interface that arises from the presence of an internal recombination pathway. The highest energy conversion efficiency (η) of 3.16% is obtained under standard air mass 1.5 global (AM 1.5G) simulated sun light by doping the optimized amount of Co2+ ion in CdS nanoparticles, corresponding to efficiency increment (35%) compared to the un-doped system. The origin of the increase in the efficiency is attributed to the dominance of charge collection to recombination. To further investigation of the electron transport time in the photoanode, the intensity modulated photocurrent spectroscopy (IMPS) is performed under standard conditions. Our obtained results can help to develop a simple and effective method to enhance the efficiency in the QDSSCs.

  19. Photocatalytic decomposition of hydrogen sulfide on cadmium and zinc sulfides immobilized on a cation exchange film

    SciTech Connect

    Makhmadmurodov, A.; Gruzdkov, Y.A.; Parmon, V.N.; Savinov, E.N.

    1986-08-01

    The photocatalytic decomposition of hydrogen sulfide on cadmium, zinc, and tin sulfides, immobilized on a polymer, was studied. Activation of the photocatalyst by finely divided particles of Pd and Pt was used. A quantum yield of 9.5% was achieved.

  20. Photoreduction of bicarbonate catalyzed by supported cadmium sulfide.

    PubMed

    Kisch, Horst; Lutz, Peter

    2002-04-01

    Cadmium sulfide supported on silica (CdS-chi/SiO2, chi = 4, 11, 17, 25%) and zinc sulfide (CdS-chi/ZnS, chi = 5, 10, 20, 30%) was prepared by impregnation with cadmium sulfate and subsequent addition of sodium sulfide. The specific surface areas of the silica and zinc sulfide supported powders are in the range o f 188-280 and 95-104 m2 g(-1), respectively. After sonication of an aqueous suspension of CdS-17/SiO2 the particle size distribution exhibited two maxima at 22 and 57 microm. In the presence of sodium sulfite the supported cadmium sulfides photocatalyze the reduction of bicarbonate to formate, formaldehyde, and oxalate. Upon polychromatic irradiation (lambda > or = 290 nm) the C1-products formate and formaldehyde were obtained in concentrations of 30-130 microM whereas the C2-product oxalate reached only 1-8 microM. Formaldehyde is not formed through reduction of intermediate formate whereas oxalate is produced via oxidation of the latter. The linear increase of oxalate concentration with coverage can be rationalized by the assumption that dimerization of the intermediate carbon dioxide radical anion does not occur on the cadmium sulfide but in solution or on the silica surface. For zinc sulfide supported samples the coverages of 10, 20, and 30% do not change the photocatalytic activity significantly whereas a loading of 5% induces a 40-fold and 16-fold increase as compared to unmodified cadmium and zinc sulfide, respectively. This strong enhancement suggests that in CdS-05/ZnS the efficiency of charge separation is strongly improved through interparticle electron transfer. The results demonstrate that both silica and zinc sulfide supports increase the photocatalytic activity of cadmium sulfide through the presence of a recently found electronic semiconductor-support interaction (SEMSI effect). Additionally, the low coverage sample CdS-05/ZnS combines this novel effect with the higher charge separation efficiency of a coupled semiconductor system.

  1. Solid-state phase diagram of the zinc sulfide-cadmium sulfide system

    SciTech Connect

    Fedorov, V.A.; Ganshin, V.A.; Korkishko, Y.N. )

    1993-01-01

    The II-VI wide-band compounds zinc sulfide, cadmium sulfide and Cd[sub x]ZN[sub 1[minus]x]S ternary alloys has been of considerable technological interest due to their semiconducting, optical and mechanical properties and are of considerable importance as photoconductors, phosphors, infrared and solar-cell window materials and materials for short-wavelength optoelectronic applications. Structures and phase relation in the ZnS-CdS system were investigated in the temperature range 150-700 C and the boundaries describing the equilibria between the zinc-blend and wurtzite Cd[sub x]An[sub 1[minus]x]S solid solutions were determined by examining the ion exchange processes Cd[sup 2+] [r arrow] Zn[sup 2+] in the ZnS powder. The complete thermodynamical description of the ZnS-CdS system is proposed. It was found, that Cd[sub x]Z[sub n[minus]1]S solid solutions of both modifications obey a regular solution model. Enthalpies of the zinc-blend-to-wurtzite structural phase transition in CdS (550[plus minus]50 J/mol) and in ZnS (1700[plus minus]100 J/mol) were defined. The solid state phase diagram calculated from defined thermodynamical parameters agrees well with the experimental data.

  2. A simple route to synthesize carbon-nanotube/cadmium-sulfide hybrid heterostructures and their optical properties

    SciTech Connect

    Zhao Yongbin; Liu Haijing; Wang Feng; Liu Jingjun; Chul Park, Ki; Endo, Morinobu

    2009-04-15

    Multi-walled carbon nanotube/cadmium sulfide hybrid heterostructures were easily synthesized by employing a thermal decomposition of thioacetamide as a sulfide-ion source in an aqueous regime. The resulting cadmium-sulfide phase is comprised of a zinc-blende structure of spherical polycrystalline nanoparticles (cadmium-sulfide nanoclusters) with the subunits of ca. 15 nm, deposited on the nanotube surface. The formation of the cadmium-sulfide nanoparticles with zinc-blende structure (cubic crystal) suggests that the local concentrations of reacting ion species in the vicinity of the nanotube surface are different from those in the reaction solution. The cadmium-sulfide nanoparticles are comprised of a stoichiometrically ideal chemical-composition ratio (cadmium: sulfur=1:1.02) of cadmium and sulfur with the valence states of +2 and -2, respectively. The optical responses of the cadmium-sulfide phase for ultraviolet-visible light and photoluminescence spectroscopes show the proper size-effect and inherent optical properties of the cadmium-sulfide nanoparticles. - Graphical abstract: Transmission electron micrograph observation and electron diffraction pattern analysis of MWCNT/CdS heterostructures, which show that CdS nanoparticles with cubic CdS phase are deposited on the surface of MWCNTs.

  3. Room temperature chemical bath deposition of cadmium selenide, cadmium sulfide and cadmium sulfoselenide thin films with novel nanostructures

    NASA Astrophysics Data System (ADS)

    VanderHyde, Cephas A.; Sartale, S. D.; Patil, Jayant M.; Ghoderao, Karuna P.; Sawant, Jitendra P.; Kale, Rohidas B.

    2015-10-01

    A simple, convenient and low cost chemical synthesis route has been used to deposit nanostructured cadmium sulfide, selenide and sulfoselenide thin films at room temperature. The films were deposited on glass substrates, using cadmium acetate as cadmium ion and sodium selenosulfate/thiourea as a selenium/sulfur ion sources. Aqueous ammonia was used as a complex reagent and also to adjust the pH of the final solution. The as-deposited films were uniform, well adherent to the glass substrate, specularly reflective and red/yellow in color depending on selenium and sulfur composition. The X-ray diffraction pattern of deposited cadmium selenide thin film revealed the nanocrystalline nature with cubic phase; cadmium sulfide revealed mixture of cubic along with hexagonal phase and cadmium sulfoselenide thin film were grown with purely hexagonal phase. The morphological observations revealed the growth and formation of interesting one, two and three-dimensional nanostructures. The band gap of thin films was calculated and the results are reported.

  4. Vertical growth of cadmium sulfide crystals on a silicon substrate

    NASA Astrophysics Data System (ADS)

    Belyaev, A. P.; Rubets, V. P.; Antipov, V. V.

    2017-02-01

    The results of the technological and microscopy studies of the mechanisms of the vertical growth of cadmium sulfide crystals during vacuum synthesis from the vapor phase were reported. Whisker crystals with a diameter from 10 nm to a few micrometers and with a length of dozens of millimeters can be grown by the vacuum vapor phase synthesis in a quasi-closed volume. The results of studies are satisfactorily explained in terms of the classical vapor-liquid-crystal model. The SEM micrographs are presented.

  5. Structural and electronic properties of cadmium sulfide clusters

    SciTech Connect

    Joswig, J.O.; Springborg, M.; Seifert, G.

    2000-03-30

    Crystalline cadmium sulfide is a semiconductor for which the wurtzite and zinc blend structures are energetically almost degenerate. Due to quantum-confinement effects, it is possible to tune the optical properties of finite cadmium sulfide clusters by varying their size. The authors report results of a theoretical study devoted to the properties of stoichiometric Cd{sub n}S{sub n} clusters as a function of their size n. The authors have optimized the structure, whereby the initial structures are spherical parts of either of the two crystal structures, and have studied systems with up to almost 200 atoms. The calculations were performed by using a simplified LCAO-DFT-LDA scheme. The results include the structure, electronic energy levels (in particular the frontier orbitals HOMO and LUMO), and stability as a function of size. The results allow for a unique definition of a surface region. The Mulliken populations indicate that the bonds within this region are more ionic than in the bulk. Furthermore, whereas the HOMO is delocalized over major parts of the nanoparticle, the LUMO is a surface state, which confirms recent experimental findings. Finally, the relative stability of the zinc blend and wurtzite structures is strongly dependent on the size of the system, and there is a close connection between the HOMO-LUMO energy gap and stability.

  6. Selective Facet Reactivity During Cation Exchange in Cadmium Sulfide Nanorods

    SciTech Connect

    Sadtler, Bryce; Demchenko, Denis; Zheng, Haimei; Hughes, Steven; Merkle, Maxwell; Dahmen, Ulrich; Wang, Lin-Wang; Alivisatos, A. Paul

    2008-12-18

    The partial transformation of ionic nanocrystals through cation exchange has been used to synthesize nanocrystal heterostructures. We demonstrate that 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. In the case of copper I (Cu+) cation exchange in cadmium sulfide (CdS) nanorods, the reaction starts preferentially at the ends of the nanorods such that copper sulfide (Cu2S) grows inwards from either end. The resulting morphology is very different from the striped pattern obtained in our previous studies of silver I (Ag+) exchange in CdS nanorods where non-selective nucleation of silver sulfide (Ag2S) occurs. From interface formation energies calculated for several models of epitaxialconnections between CdS and Cu2S or Ag2S, we infer the relative stability of each interface during the nucleation and growth of Cu2S or Ag2S within the CdS nanorods. The epitaxial connections of Cu2S to the end facets of CdS nanorods minimize the formation energy, making these interfaces stable throughout the exchange reaction. However, as the two end facets of wurtzite CdS nanorods are crystallographically nonequivalent, asymmetric heterostructures can be produced.

  7. Cadmium Telluride, Cadmium Telluride/Cadmium Sulfide Core/Shell, and Cadmium Telluride/Cadmium Sulfide/Zinc Sulfide Core/Shell/Shell Quantum Dots Study

    NASA Astrophysics Data System (ADS)

    Yan, Yueran

    CdTe, CdTe/CdS core/shell, and CdTe/CdS/ZnS core/shell/shell quantum dots (QDs) are potential candidates for bio-imaging and solar cell applications because of some special physical properties in these nano materials. For example, the band gap energy of the bulk CdTe is about 1.5 eV, so that principally they can emit 790 nm light, which is in the near-infrared range (also called biological window). Moreover, theoretically hot exciton generated by QDs is possible to be caught since the exciton relaxation process in QDs is slower than in bulk materials due to the large intraband energy gap in QDs. In this dissertation, we have synthesized the CdTe and CdTe/CdS core/shell QDs, characterized their structure, and analyzed their photophysical properties. We used organometallic methods to synthesize the CdTe QDs in a noncoordinating solvent. To avoid being quenched by air, ligands, solvent, or other compounds, CdS shell was successfully deposited on the CdTe QDs by different methods, including the slow injection method, the successive ion layer adsorption and reaction (SILAR) method, and thermal-cycling coupled single precursor method (TC-SP). Our final product, quasi-type- II CdTe/CdS core/shell QDs were able to emit at 770 nm with a fluorescence quantum yield as high as 70%. We also tried to deposit a second shell ZnS on CdTe/CdS core/shell QDs since some compounds can quench CdTe/CdS core/shell QDs. Even though different methods were used to deposit ZnS shell on the CdTe/CdS core/shell QDs, CdTe/CdS/ZnS core/shell/shell QDs still can be quenched. Furthermore, the CdTe/CdS core/shell and CdTe/CdS/ZnS core/shell/shell QDs were transferred into aqueous phase, phosphate buffered saline or deionized water, by switching the hydrophilic ligands (thiol or PEG ligands). The thioglycolic acid (TGA)-capped CdTe/CdS core/shell QDs can be kept in aqueous phase with high fluorescence quantum yield (60%--70%) for more than two months. However, some other compounds in organic or

  8. Photo-enhanced field electron emission of cadmium sulfide nanowires

    NASA Astrophysics Data System (ADS)

    Zhang, Jinling; Lv, Yinghua; Liu, Ning; Li, Yanqing; Gao, Peng; Bai, Xuedong

    2011-11-01

    The response of field electron emission of cadmium sulfide (CdS) nanowires (NWs) to visible light has been investigated. It is found that, upon light illumination, the turn-on voltage drops, emission current increases obviously, and the Fowler-Nordheim behavior deviates from a straight line. A process of field emission coupled with semiconducting properties of CdS NWs is proposed. Photon-excited electron transition from the valence band to the conductance band of CdS nanowires increases the quantity of emitting electrons, and the photoemission decreases the effective work function of CdS emitters, which largely enhances the field emission performance. The response of field emission of CdS NWs to light illumination suggests an approach for tuning field emission of semiconductor emitters.

  9. In situ synthesis of binary cobalt-ruthenium nanofiber alloy counter electrode for electrolyte-free cadmium sulfide quantum dot solar cells

    NASA Astrophysics Data System (ADS)

    Du, Nan; Ren, Lei; Sun, Weifu; Jin, Xiao; Zhao, Qing; Cheng, Yuanyuan; Wei, Taihuei; Li, Qinghua

    2015-06-01

    A facile, low-cost and low-temperature fabrication approach of counter electrode is essential for pursuing robust photovoltaic devices. Herein, we develop a hydrothermal in situ growth of Cobalt-Ruthenium (Co-Ru) alloy nanofiber electrode for quantum dot solar cell (QDSC) applications. Colloidal CdS QDs with tunable absorption band edge are synthesized and used as light absorber. After optimizing the QDs with the highest photoluminescence quantum yield accompanied by considerable solar light absorption ability, QDSC based on Co-Ru alloy electrode delivers a much higher power conversion efficiency than its counterparts, i.e., either pure Co or Ru metal electrodes. In detail, Co-Ru alloy electrode exhibits high specific area, excellent electrical behavior, intimate interface contact, and good stability, thus leading to notable improved device performances. The impressive robust function of Co-Ru alloy with simple manufacturing procedure highlights its potential applications in robust QDSCs.

  10. Beyond 11% efficient sulfide kesterite Cu2ZnxCd1–xSnS4 solar cell: Effects of cadmium alloying

    DOE PAGES

    Yan, Chang; Sun, Kaiwen; Huang, Jialiang; ...

    2017-04-03

    Here, kesterite Cu2ZnSnS4 (CZTS) thin-film solar cells have drawn worldwide attention because of outstanding performance and earth-abundant constituents. However, problems such as coexistence of complex secondary phases, the band tailing issue, short minority lifetime, bulk defects, and undesirable band alignment at p-n interfaces need to be addressed for further efficiency improvement. In this regard, Cd alloying shows promise for dealing with some of these problems. In this work, a beyond 11% efficient Cd-alloyed CZTS solar cell is achieved, and the effects of Cd-alloying and mechanism underpinning the performance improvement have been investigated. The introduction of Cd can significantly reduce themore » band tailing issue, which is confirmed by the reduction in the difference between the photoluminescence peak and optical band gap (Eg) as well as decreased Urbach energy. The microstructure, minority lifetime, and electrical properties of CZTS absorber are greatly improved by Cd alloying. Further XPS analyses show that the partial Cd alloying slightly reduces the band gap of CZTS via elevating the valence band maximum of CZTS. This suggests that there are opportunities for further efficiency improvement by engineering the absorber and the associated interface with the buffer.« less

  11. Titanium Dioxide/Upconversion Nanoparticles/Cadmium Sulfide Nanofibers Enable Enhanced Full-Spectrum Absorption for Superior Solar Light Driven Photocatalysis.

    PubMed

    Zhang, Fu; Zhang, Chuan-Ling; Wang, Wan-Ni; Cong, Huai-Ping; Qian, Hai-Sheng

    2016-06-22

    In this work, we demonstrate an electrospinning technique to fabricate TiO2 /upconversion nanoparticles (UCNPs)/CdS nanofibers on large scale. In addition, the as-prepared TiO2 nanofibers are incorporated with a high population of UCNPs and CdS nanospheres; this results in Förster resonance energy-transfer configurations of the UCNPs, TiO2 , and CdS nanospheres that are in close proximity. Hence, strong fluorescent emissions for the Tm(3+) ions including the (1) G4 →(3) H6 transition are efficiently transferred to TiO2 and the CdS nanoparticles through an energy-transfer process. The as-prepared TiO2 /UCNPs/CdS nanofibers exhibit full-spectrum solar-energy absorption and enable the efficient degradation of organic dyes by fluorescence resonance energy transfer between the UCNPs and TiO2 (or CdS). The UCNPs/TiO2 /CdS nanofibers may also have enhanced energy-transfer efficiency for wide applications in solar cells, bioimaging, photodynamics, and chemotherapy.

  12. Fabrication of polymer/cadmium sulfide hybrid solar cells [P3HT:CdS and PCPDTBT:CdS] by spray deposition.

    PubMed

    Kumar, Neetesh; Dutta, Viresh

    2014-11-15

    This paper investigates fabrication of surfactant free CdS nanoparticles (NPs) and application in the fabrication of P3HT:CdS and PCPDTBT:CdS bulk-heterojunction hybrid solar cells using high-throughput, large-area, low cost spray deposition technique. Both the hybrid active layers and hole transport layers are deposited by spray technique. The CdS/Poly(3-hexylthiophene-2,5-diyl) (P3HT) and CdS/Poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']dithiophene)-alt-4,7(2,1,3-benzothiadiazole)] (PCPDTBT) hybrid devices are fabricated by spray deposition process at optimized conditions (i.e. film thickness, spray solution volume, distance between sample and spray nozzle, substrate temperature, etc.). The power conversion efficiency of η=0.6% and 1.02% is obtained for P3HT:CdS and PCPDTBT:CdS hybrid devices, respectively. Spray coating holds significant promise as a technique capable of fabricating large-area, high performance hybrid solar cells. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Effect of temperature and illumination of streamer discharges in cadmium sulfide and cadmium selenide single crystals

    SciTech Connect

    Gladyshchuk, A.A.; Gurskii, A.L.; Parashchuk, V.V.; Yablonskii, G.P.

    1986-12-01

    The excitation conditions, the orientation, the radiation spectra of streamer discharges and the effect of laser illumination and temperature on the properties of streamers in cadmium sulfide single crystals has appeared in previous studies. Light generation in CdSe single crystals and in the mixed compounds CdS/sub x/Se/sub 1-x/ was obtained with streamer excitation through detailed information on the crystallographic orientation of the streamers and radiation spectra of these crystals. In this paper, the authors present new data on the effect of the temperature and illumination in the region 77-520/sup 0/K on the probability of excitation and the orientation of streamer discharges in cadmium sulfide crystals; the characteristic features of excitation, orientation, and luminescence spectra of streamer discharges in CdS/sub x/Se/sub 1-x/. The crystals were illuminated with radiation from an incandescent lamp with controllable intensity in the spectral range 560-580 nm and by impulsive radiation from an LGT-21 nitrogen laser (wavelength = 337.1 nm and I/sub e/ = 30 kW/cm/sup 2/. The resistivity of the crystalline plates as a function of the illumination intensity was determined from measurements of the photoconductivity. The streamer illumination of the discharge was separated from the illumination background by interference light filters.

  14. Photochemical hydrogen production with platinized suspensions of cadmium sulfide and cadmium zinc sulfide modified by silver sulfide

    SciTech Connect

    Reber, J.F.; Rusek, M.

    1986-02-27

    An efficient hydrogen production can be achieved by irradiated suspensions of platinized CdS in solutions of S/sup 2 -/ and/or SO/sub 3//sup 2 -/ ions. However, the photocatalytic activity of CdS powders strongly depends on their specific surface area. However, coprecipitation of CdS with about 0.5-3 wt% silver sulfide or surface modification of CdS with a large specific surface area by silver ions permitted preparation of very active platinized photocatalysts. The enhancement of activity is not limited to the absorption range of CdS, but also results from a significant extension of the spectral response up to about 620 nm. Further improvement of the photoactivity can be achieved by doping the Ag/sub 2/S activated CdS powders with zinc sulfide. 77 references, 17 figures.

  15. Experimental simulations of sulfide formation in the solar nebula.

    PubMed

    Lauretta, D S; Lodders, K; Fegley, B

    1997-07-18

    Sulfurization of meteoritic metal in H2S-H2 gas produced three different sulfides: monosulfide solid solution [(Fe,Ni)1-xS], pentlandite [(Fe,Ni)9-xS8], and a phosphorus-rich sulfide. The composition of the remnant metal was unchanged. These results are contrary to theoretical predictions that sulfide formation in the solar nebula produced troilite (FeS) and enriched the remaining metal in nickel. The experimental sulfides are chemically and morphologically similar to sulfide grains in the matrix of the Alais (class CI) carbonaceous chondrite, suggesting that these meteoritic sulfides may be condensates from the solar nebula.

  16. Support-controlled chemoselective olefin-imine addition photocatalyzed by cadmium sulfide on a zinc sulfide carrier.

    PubMed

    Gärtner, Marc; Ballmann, Joachim; Damm, Cornelia; Heinemann, Frank W; Kisch, Horst

    2007-02-01

    The semiconductor catalyzed photoaddition of cyclopentene or cyclohexene to various novel electron-poor imines of type p-XC(6)H(4)(CN)C[double bond, length as m-dash]N(COPh) (X = H, F, Cl, Br, Me, MeO) was investigated as a function of the nature of the cadmium sulfide photocatalyst. Irradiation (lambda>/= 350 nm) of silica supported cadmium sulfide surprisingly did not afford the expected olefin-imine adducts but an imine hydrocyanation product via an unprecedented dark reaction. However, when silica was replaced by zinc sulfide as the support for cadmium sulfide, the expected homoallylic N-benzoyl-alpha-amino cyanides were isolated in yields of 65-84%. Thus, chemoselectivity is introduced through replacing an insulating by a semiconducting support, a hitherto unknown effect in semiconductor photocatalysis. From the sign of the time resolved photovoltage it is found that the mixed metal sulfide interface CdS/ZnS increases the lifetime of photogenerated electron-hole pairs by about one order of magnitude as compared to the SiO(2)/CdS system. The reaction rate increases with increasing imine sigma-Hammett constants and decreasing stability of intermediate benzyl radicals.

  17. 3.88% efficient tin sulfide solar cells using congruent thermal evaporation.

    PubMed

    Steinmann, Vera; Jaramillo, R; Hartman, Katy; Chakraborty, Rupak; Brandt, Riley E; Poindexter, Jeremy R; Lee, Yun Seog; Sun, Leizhi; Polizzotti, Alexander; Park, Helen Hejin; Gordon, Roy G; Buonassisi, Tonio

    2014-11-26

    Tin sulfide (SnS), as a promising absorber material in thin-film photovoltaic devices, is described. Here, it is confirmed that SnS evaporates congruently, which provides facile composition control akin to cadmium telluride. A SnS heterojunction solar cell is demons trated, which has a power conversion efficiency of 3.88% (certified), and an empirical loss analysis is presented to guide further performance improvements.

  18. Cadmium-specific formation of metal sulfide 'Q-particles' by Klebsiella pneumoniae.

    PubMed

    Holmes, J D; Richardson, D J; Saed, S; Evans-Gowing, R; Russell, D A; Sodeau, J R

    1997-08-01

    Klebsiella pneumoniae overcomes cadmium toxicity through the 'biotrans-formation' of cadmium ions into photoactive, nanometre-sized CdS particles deposited on the cell surface. The kinetics of particle formation during batch culture growth was monitored by electron microscopy (EM), energy-dispersive X-ray analysis and electronic absorption spectroscopy (EAS). During the deceleration phase of bacterial growth, the presence of CdS particles on the outer cell wall of K. pneumoniae (> or = 5 nm in diameter) was detected by EM. The size of these electron-dense particles continued to increase throughout the stationary phase of growth, with some of the particles reaching a diameter > 200 nm. The formation of the extracellular CdS particles contributed to around 3-4% of the total cell biomass. EAS undertaken on these extracellular 'bio-CdS' particles suggested that the large 'superparticles' observed by EM, e.g. 200 nm, were aggregates of smaller particles termed 'Q-particles', approximately 4 nm in diameter. Metal sulfide particles were not formed in batch cultures of K. pneumoniae grown in the presence of lead, zinc, mercury, copper or silver ions. Growth in the presence of lead ions resulted in the formation of extracellular electron-dense particles containing lead but not sulfide or phosphate. Intracellular phosphorus-containing electron-opaque particles were formed during growth in the presence of copper and mercury. Intracellular electron-dense particles were formed in the presence of zinc ions but these did not contain phosphorus. From these results it was thought that metal sulfide formation in K. pneumoniae showed some cadmium-specificity. When cadmium and zinc ions were both added to the growth medium, metal sulfide particles were formed that were predominantly composed of cadmium, e.g. 48.6% cadmium and 0.04% zinc. Similarly, when cadmium and lead ions were both present during growth only CdS particles formed. In both cases analysis of the cells by EAS confirmed

  19. A Satellite Borne Cadmium Sulfide Total Corpuscular Energy Detector

    NASA Technical Reports Server (NTRS)

    Freeman, John W.

    1961-01-01

    The properties of single crystals of cadmium sulfide as radiation detectors are described. It has been found possible to select crystals such that: (a) The ratio of increase of conductivity under irradiation to the rate of absorption of energy in the crystal is substantially independent of particle energy (over the examined ranges of 500 ev to 80 kev for electrons and 5 kev to 180 kev for protons) and of the magnitude of energy flux (over the range from.005 to 10 ergs/cm(sup 2 -sec); and (b) The above ration is substantially the same for protons, electrons, alpha particles, x-rays, and gamma-rays. For a driving voltage of 100 volts, typical crystal yield currents of 10(sup -7) to 10(sup- 6) amperes for each erg/cm(sup 2-sec) of energy absorbed by the crystal. The threshold of such crystal detectors (resulting from dark currents of the order of 10(sup 10 amp) is typically 10(sup -3) ergs/cm(sup 2- sec). For the selected crystals a response-temperature coefficient of -0.25% per degree centigrade is found for the temperature range -50 deg C to + 50 deg C. A description is given of a complete CdS total corpuscular energy detector for the study of geomagnetically trapped radiation by means of a satellite. The detector described has a dynamic range great than 10(sup 4), a solid angle of 10(exp -3) steradian, and a detection threshold of approximately 1 erg/cm(sup 2-sec-sterad). A similar detector employing a small magnet for the selective exclusion of electrons is also described. Noteworthy practical features of these detectors for satellite and space probe experiments are: (a) Use of bare crystals, without covering foils, in order to detect charged particles having energies as low as hundreds of electron volts. (b) Simplicity of electronic auxiliaries. (c) Compactness, lightweight and nechanical ruggedness. (d) Low electrical power requirements; and (e) Conversion of conduction current to the rate of a twostate relaxation oscillator in order to facilitate telemetric

  20. Method of forming solar cells by grid contact isolation

    SciTech Connect

    Biter, W.J.

    1982-03-16

    A solar cell structure is produced by a method comprising baking the solar cell, containing a gridded top layer of cuprous sulfide formed on a base of cadmium sulfide, for 20 minutes to 10 hours, to produce a copper doped cds electrically insulating region in the cadmium sulfide base near the interface of the cuprous sulfide and the cadmium sulfide; removing the cuprous sulfide, and the copper doped cds insulating region not covered by the grid, to provide a bare cadmium sulfide areas; and then forming a cuprous sulfide layer on the exposed areas not covered by the grid.

  1. Release of dissolved cadmium and sulfur nanoparticles from oxidizing sulfide minerals

    EPA Science Inventory

    Cadmium enrichment (relative to Fe and Zn) in paddy rice grain occurs during the pre-harvest drainage of flooded soil, which causes oxidative dissolution of sulfide minerals present in reduced soil. We investigated this process over a range of environmentally realistic Cdcontain...

  2. Biexciton in nanosystem of quantum dots of cadmium sulfide in a dielectric matrix

    NASA Astrophysics Data System (ADS)

    Pokutnii, S. I.

    2016-11-01

    A significant increase in the binding energy of the singlet ground state of biexciton (of spatially separated electrons and holes) in a nanosystem that consists of CdS quantum dots grown in a borosilicate glass matrix has been predicted; the effect is almost two orders of magnitude larger than the binding energy of biexciton in a sulfide cadmium single crystal.

  3. Cadmium zinc sulfide/copper indium diselenide module design and cost assessment

    SciTech Connect

    Jackson, B.

    1985-09-01

    The report presents the results of a cadmium zinc sulfide/copper indium diselenide. The primary objective of the research was to clarify several of the technical issues facing the technology development. The design work focused on a large four-foot-square module suited for utility or large scale commercial applications. Cost estimates were developed from detailed descriptions of each manufacturing process step.

  4. Release of dissolved cadmium and sulfur nanoparticles from oxidizing sulfide minerals

    EPA Science Inventory

    Cadmium enrichment (relative to Fe and Zn) in paddy rice grain occurs during the pre-harvest drainage of flooded soil, which causes oxidative dissolution of sulfide minerals present in reduced soil. We investigated this process over a range of environmentally realistic Cdcontain...

  5. A new Klebsiella planticola strain (Cd-1) grows anaerobically at high cadmium concentrations and precipitates cadmium sulfide.

    PubMed

    Sharma, P K; Balkwill, D L; Frenkel, A; Vairavamurthy, M A

    2000-07-01

    Heavy metal resistance by bacteria is a topic of much importance to the bioremediation of contaminated soils and sediments. We report here the isolation of a highly cadmium-resistant Klebsiella planticola strain, Cd-1, from reducing salt marsh sediments. The strain grows in up to 15 mM CdCl(2) under a wide range of NaCl concentrations and at acidic or neutral pH. In growth medium amended with thiosulfate, it precipitated significant amounts of cadmium sulfide (CdS), as confirmed by x-absorption spectroscopy. In comparison with various other strains tested, Cd-1 is superior for precipitating CdS in cultures containing thiosulfate. Thus, our results suggest that Cd-1 is a good candidate for the accelerated bioremediation of systems contaminated by high levels of cadmium.

  6. Cadmium sulfide/copper ternary heterojunction cell research

    NASA Astrophysics Data System (ADS)

    Devaney, W. E.; Mickelsen, R. A.; Chen, W. S.; Stanbery, B. J.; Stewart, J. M.; Lytle, F. W.; Burnett, A. F.

    1987-11-01

    This is the final technical progress report on a thirty-two month research program on CuInSe2 and CuInGaSe2 based thin-film polycrystalline heterojunction solar cells. CuInGaSe2 films incorporating Ga fractions (x in CuIn(1-x)Ga(x)Se2) from 0.04 to 1.0 have been prepared and characterized. CuInGaSe2/CdZnS heterojunction devices have been fabricated for a range of Ga contents and show the expected variations in Voc and spectral response with Ga content. An efficiency of 10.2 percent (SERI test, ASTM87) has been measured for a cell with Ga fraction of 0.23, the highest efficiency reported for this material. A CuInSe2/CdZnS monolithically interconnected four cell series string of 91 sq cm area has been fabricated with a total area efficiency of 9.5 percent (SERI test, ASTM87). Results are presented on Ion-Assisted Deposition of the selenide and sulfide, on a new design for the Se evaporation source, on ITO reactive sputter deposition, and on CdZnS films prepared from an E-Gun Evaporation source. Spectral response and I-V characteristic variations with selenide composition before and after heat-treatment are discussed for the CuInSe2/CdZnS devices. The highest AM1 total area efficiency for the CuInSe2/CdZnS cell is now 11.9 percent (Boeing test, AM1 spectrum) with five cells measured over the previously reported high of 10.9 percent. Room Temperature Photoluminescence, Voltage Contrast Imaging of junction cross sections, Raman spectroscopy, and EXAFS measurements on the CuInSe2/CdZnS devices are also presented and discussed.

  7. Investigation of annealing temperature effect on magnetron sputtered cadmium sulfide thin film properties

    NASA Astrophysics Data System (ADS)

    Akbarnejad, E.; Ghorannevis, Z.; Abbasi, F.; Ghoranneviss, M.

    2017-03-01

    Cadmium sulfide (CdS) thin films are deposited on the fluorine doped tin oxide coated glass substrate using the radio frequency magnetron sputtering setup. The effects of annealing in air on the structural, morphological, and optical properties of CdS thin film are studied. Optimal annealing temperature is investigated by annealing the CdS thin film at different annealing temperatures of 300, 400, and 500 °C. Thin films of CdS are characterized by X-ray diffractometer analysis, field emission scanning electron microscopy, atomic force microscopy, UV-Vis-NIR spectrophotometer and four point probe. The as-grown CdS films are found to be polycrystalline in nature with a mixture of cubic and hexagonal phases. By increasing the annealing temperature to 500 °C, CdS film showed cubic phase, indicating the phase transition of CdS. It is found from physical characterizations that the heat treatment in air increased the mean grain size, the transmission, and the surface roughness of the CdS thin film, which are desired to the application in solar cells as a window layer material.

  8. Investigation of annealing temperature effect on magnetron sputtered cadmium sulfide thin film properties

    NASA Astrophysics Data System (ADS)

    Akbarnejad, E.; Ghorannevis, Z.; Abbasi, F.; Ghoranneviss, M.

    2016-12-01

    Cadmium sulfide (CdS) thin films are deposited on the fluorine doped tin oxide coated glass substrate using the radio frequency magnetron sputtering setup. The effects of annealing in air on the structural, morphological, and optical properties of CdS thin film are studied. Optimal annealing temperature is investigated by annealing the CdS thin film at different annealing temperatures of 300, 400, and 500 °C. Thin films of CdS are characterized by X-ray diffractometer analysis, field emission scanning electron microscopy, atomic force microscopy, UV-Vis-NIR spectrophotometer and four point probe. The as-grown CdS films are found to be polycrystalline in nature with a mixture of cubic and hexagonal phases. By increasing the annealing temperature to 500 °C, CdS film showed cubic phase, indicating the phase transition of CdS. It is found from physical characterizations that the heat treatment in air increased the mean grain size, the transmission, and the surface roughness of the CdS thin film, which are desired to the application in solar cells as a window layer material.

  9. Cadmium sulfide quantum dots induce oxidative stress and behavioral impairments in the marine clam Scrobicularia plana.

    PubMed

    Buffet, Pierre-Emmanuel; Zalouk-Vergnoux, Aurore; Poirier, Laurence; Lopes, Christelle; Risso-de-Faverney, Christine; Guibbolini, Marielle; Gilliland, Douglas; Perrein-Ettajani, Hanane; Valsami-Jones, Eugenia; Mouneyrac, Catherine

    2015-07-01

    Cadmium sulfide (CdS) quantum dots have a number of current applications in electronics and solar cells and significant future potential in medicine. The aim of the present study was to examine the toxic effects of CdS quantum dots on the marine clam Scrobicularia plana exposed for 14 d to these nanomaterials (10 µg Cd L(-1) ) in natural seawater and to compare them with soluble Cd. Measurement of labile Cd released from CdS quantum dots showed that 52% of CdS quantum dots remained in the nanoparticulate form. Clams accumulated the same levels of Cd regardless of the form in which it was delivered (soluble Cd vs CdS quantum dots). However, significant changes in biochemical responses were observed in clams exposed to CdS quantum dots compared with soluble Cd. Increased activities of catalase and glutathione-S-transferase were significantly higher in clams exposed in seawater to Cd as the nanoparticulate versus the soluble form, suggesting a specific nano effect. The behavior of S. plana in sediment showed impairments of foot movements only in the case of exposure to CdS quantum dots. The results show that oxidative stress and behavior biomarkers are sensitive predictors of CdS quantum dots toxicity in S. plana. Such responses, appearing well before changes might occur at the population level, demonstrate the usefulness of this model species and type of biomarker in the assessment of nanoparticle contamination in estuarine ecosystems. © 2015 SETAC.

  10. Hydrogen sulfide modulates cadmium-induced physiological and biochemical responses to alleviate cadmium toxicity in rice

    PubMed Central

    Mostofa, Mohammad Golam; Rahman, Anisur; Ansary, Md. Mesbah Uddin; Watanabe, Ayaka; Fujita, Masayuki; Phan Tran, Lam-Son

    2015-01-01

    We investigated the physiological and biochemical mechanisms by which H2S mitigates the cadmium stress in rice. Results revealed that cadmium exposure resulted in growth inhibition and biomass reduction, which is correlated with the increased uptake of cadmium and depletion of the photosynthetic pigments, leaf water contents, essential minerals, water-soluble proteins, and enzymatic and non-enzymatic antioxidants. Excessive cadmium also potentiated its toxicity by inducing oxidative stress, as evidenced by increased levels of superoxide, hydrogen peroxide, methylglyoxal and malondialdehyde. However, elevating endogenous H2S level improved physiological and biochemical attributes, which was clearly observed in the growth and phenotypes of H2S-treated rice plants under cadmium stress. H2S reduced cadmium-induced oxidative stress, particularly by enhancing redox status and the activities of reactive oxygen species and methylglyoxal detoxifying enzymes. Notably, H2S maintained cadmium and mineral homeostases in roots and leaves of cadmium-stressed plants. By contrast, adding H2S-scavenger hypotaurine abolished the beneficial effect of H2S, further strengthening the clear role of H2S in alleviating cadmium toxicity in rice. Collectively, our findings provide an insight into H2S-induced protective mechanisms of rice exposed to cadmium stress, thus proposing H2S as a potential candidate for managing toxicity of cadmium, and perhaps other heavy metals, in rice and other crops. PMID:26361343

  11. Hydrogen sulfide modulates cadmium-induced physiological and biochemical responses to alleviate cadmium toxicity in rice.

    PubMed

    Mostofa, Mohammad Golam; Rahman, Anisur; Ansary, Md Mesbah Uddin; Watanabe, Ayaka; Fujita, Masayuki; Tran, Lam-Son Phan

    2015-09-11

    We investigated the physiological and biochemical mechanisms by which H2S mitigates the cadmium stress in rice. Results revealed that cadmium exposure resulted in growth inhibition and biomass reduction, which is correlated with the increased uptake of cadmium and depletion of the photosynthetic pigments, leaf water contents, essential minerals, water-soluble proteins, and enzymatic and non-enzymatic antioxidants. Excessive cadmium also potentiated its toxicity by inducing oxidative stress, as evidenced by increased levels of superoxide, hydrogen peroxide, methylglyoxal and malondialdehyde. However, elevating endogenous H2S level improved physiological and biochemical attributes, which was clearly observed in the growth and phenotypes of H2S-treated rice plants under cadmium stress. H2S reduced cadmium-induced oxidative stress, particularly by enhancing redox status and the activities of reactive oxygen species and methylglyoxal detoxifying enzymes. Notably, H2S maintained cadmium and mineral homeostases in roots and leaves of cadmium-stressed plants. By contrast, adding H2S-scavenger hypotaurine abolished the beneficial effect of H2S, further strengthening the clear role of H2S in alleviating cadmium toxicity in rice. Collectively, our findings provide an insight into H2S-induced protective mechanisms of rice exposed to cadmium stress, thus proposing H2S as a potential candidate for managing toxicity of cadmium, and perhaps other heavy metals, in rice and other crops.

  12. Triton-X mediated interconnected nanowalls network of cadmium sulfide thin films via chemical bath deposition and their photoelectrochemical performance

    NASA Astrophysics Data System (ADS)

    Vanalakar, S. A.; Mali, S. S.; Jo, E. A.; Kim, J. Y.; Kim, J. H.; Patil, P. S.

    2014-10-01

    Thin films of cadmium sulfide (CdS) have been wet chemically deposited onto fluorine-doped tin oxide (FTO) coated conducting glass substrates by using non-ionic surfactant; Triton-X 100. An aqueous solution contains cadmium sulphate as a cadmium and thiourea as sulphur precursor. Ammonia used as a complexing agent. The results of measurements of the x-ray diffraction, Raman spectroscopy, optical spectroscopy, energy dispersive spectroscopy, scanning electron microscopy, Brunauer Emmett Teller (BET) surface areas and atomic force microscopy were used for the characterization of the films. These results revealed that the films are polycrystalline, consisting of CdS cubic phase. The films show a direct band gap with energy 2.39 eV. The films show interconnected nanowalls like morphology with well-defined surface area. Finally, the photoelectrochemical (PEC) performance of Triton-X mediated CdS thin film samples were studied. The sample shows photoelectrochemical (PEC) performance with maximum short circuit current density (Jsc) 1.71 mA/cm2 for larger area (1 cm2) solar cells.

  13. Spectroscopically characterized cadmium sulfide quantum dots lengthening the lag phase of Escherichia coli growth

    NASA Astrophysics Data System (ADS)

    Jaiganesh, T.; Daisy Vimala Rani, J.; Girigoswami, Agnishwar

    2012-06-01

    The present study reports the effect of cadmium sulfide (CdS) quantum dots on the life cycle of Escherichia coli. CdS quantum dots were synthesized by pH sensitive organochemical route using cadmium chloride and sodium sulfide as precursors and mercaptopropionic acid (MPA) as capping agent. It is observed that varying concentration of MPA leads to the production of different sized quantum dots with inverse proportionality and increment in the fluorescence quantum yield. The investigation also shows that CdS quantum dots have no antibacterial activity except it delays the log phase growth of bacteria in terms of size of the particles. The largest synthesized particles significantly elongate the lag phase growth.

  14. Enhanced photoluminescence from ordered arrays of cadmium sulfide nanotubes synthesized using nanoscale chemical reactors.

    PubMed

    Varghese, Arthur

    2014-06-01

    We report enhanced room temperature photoluminescence from ordered arrays of few micrometers long cadmium sulfide nanotubes fabricated using 'nanoscale chemical reactors' of porous alumina by a unique two-chamber synthesis without using any surfactants. Photoluminescence from these nanotubes is -20 times larger than that of nanocrystalline cadmium sulfide particles prepared by bulk mixing of the same reactants. However, we rule out any quantum size effect as a source of enhanced photoluminescence from these intentionally un-passivated nanotubes. We identify sulfur deficiency in these nanotubes and directional orientation of these ordered nanotube arrays as the main reason for its superior photoluminescence as compared to agglomerated nanocrystallites of CdS prepared by bulk mixing.

  15. Preparation and processing of monodisperse colloidal silica-cadmium sulfide nanocomposites

    SciTech Connect

    Chang, S.Y.; Liu, L.; Asher, S.A.

    1994-12-31

    A novel synthetic methodology has been developed for preparing monodisperse colloidal silica-cadmium sulfide nanocomposite spheres in the 50--300 nm size regime. This methodology uses water-in-oil microemulsions as the reaction medium. Monosize silica colloids are first produced by the controlled hydrolysis of tetraethyl orthosilicate in the micro water droplets of the microemulsion. Cadmium sulfide quantum dots are incorporated into the silica colloids during synthesis by the introductions of Cd{sup 2+} and S{sup 2{minus}} microemulsions. Various morphologies of the nanocomposite are fabricated by controlling the heterogeneous coagulation of CdS and SiO{sub 2}. Unique high surface area silica particles can be prepared when nitric acid etches out the CdS and leaves behind topologically defined voids. The CdS nanocomposites are new materials useful for non-linear optics, while the high surface area silica particles should have novel applications in areas such as catalysis.

  16. Characterization of biological iron sulfide composites and its application in the treatment of cadmium-contaminated wastewater.

    PubMed

    Yang, Yang; Xie, Yifei; Li, Xudong

    2015-03-01

    A strain of sulfate reducing bacteria, which could generate biological iron sulfide composites, was applied for Cd (II) removal from wastewater. The influence of biological iron sulfide composites dosage, initial pH and temperature on the rate of Cd (II) removal from wastewater by biological iron sulfide composites were investigated. The microscopic morphological characteristics and elemental composition changes of the biological iron sulfide before and after treatment was compared, using scanning electron microscopy and energy-dispersive spectrometry, then the mechanism of Cd (II) removal was explored. The results showed that Cd (II) reduction rate increased with increase in dosage of biological iron sulfide composites and initial temperature. At 25 degrees C, pH 4.0, with dosage of sulfide and cadmium ions molar equal to 99.93% Cd (II) was removed from cadmium wastewater (100 mg l(-1)), and the residual concentration of cadmium reached Chinese Integrated Wastewater Discharge Standard (GB8978-1996). The present study revealed that bio- precipitation of FeS, the main component of biological iron sulfide composites, played leading role in the process of Cd (II) reduction. Therefore, it is prospective to apply biological iron sulfide composites in the emergency treatment of cadmium-contaminated wastewater.

  17. Acid-volatile sulfide as a factor mediating cadmium and nickel bioavailability in contaminated sediments

    SciTech Connect

    Ankley, G.T.; Phipps, G.L.; Leonard, E.L.; Benoit, D.A.; Mattson, V.R.

    1991-01-01

    The authors investigated the influence of sulfide, measured as acid-volatile sulfide (AVS), on the bioavailability of cadmium and nickel in sediments. Seventeen samples from an estuarine system heavily contaminated with cadmium and nickel were analyzed for AVS and simultaneously extracted metals (SEM) and tested in 10-d exposures with the amphipod Hyalella azteca and the oligochaete Lumbriculus variegatus. Molar SEM(cadmium + nickel)/AVS ratios in the sediments ranged from less than one to greater than 200, with several in the range of 1 to 10. Samples with SEM/AVS ratios greater than one were consistently toxic to Hyalella azteca, whereas sediments with ratios less than one were not. Lumbriculus variegatus was less sensitive to the test sediments than Hyalella azteca, which was consistent with their relative sensitivity to cadmium and nickel in water-only exposures. SEM/AVS ratios in the sediments also appeared to be important in determining bioaccumulation of metals by Lumbriculus variegatus. These results support other studies with metal-spiked samples in demonstrating the importance of AVS in determining metal bioavailability in sediments and suggest that AVS normalization is a reasonable means for assessing the hazard of some sediment-associated metals to aquatic ecosystems.

  18. Continuous tuning of cadmium sulfide and zinc sulfide nanoparticle size in a water-in-supercritical carbon dioxide microemulsion.

    PubMed

    Fernandez, Carlos A; Wai, Chien M

    2007-01-01

    The size and size dispersion of cadmium sulfide and zinc sulfide semiconductor nanoparticles can be continuously tuned over a wide range of values by adjusting the density of the fluid phase in water-in-supercritical CO2 microemulsions. The average size of the ZnS nanoparticles decreases linearly from approximately 9.1 to 1.9 nm with increasing fluid density from 0.86 to 0.99 g cm(-3) at a water-to-surfactant ratio (W value) of 10. At a W value of 6, the particle size can be tuned from 7.0 to 1.5 nm in the same density range. In the case of CdS nanocrystals, the size varied from 7.1 to 2.0 nm when the W value was 10 and from 4.0 to 1.3 nm when the W value employed was 6, in the same density range. Monodispersive CdS and ZnS nanoparticles were synthesized by chemical reaction of cadmium or zinc nitrate with sodium sulfide, using two water-in-supercritical CO2 microemulsions as nanoreactors followed by protection with a fluorinated-thiol stabilizer. The stabilizer is introduced at 6 and 16 minutes after the mixing of the two microemulsions where the intensity of the characteristic absorption peak due to the quantum confinement properties of the CdS and ZnS nanoparticles (280 and 360 nm) reaches a maximum, respectively. The supercritical CO2 microemulsion method represents a simple approach to use a density-tunable solvent for synthesizing size-controlled semiconductor nanoparticles over a broad range of values.

  19. Cadmium-sulfide crystallites in Cd-(. gamma. EC) sub n G peptide complexes from tomato. [Lycopersicon esculentum

    SciTech Connect

    Reese, R.N.; White, C.A.; Winge, D.R. Univ. of Utah, Salt Lake City )

    1992-01-01

    Hydroponically grown tomato plants (Lycopersicon esculentum P. Mill cv Golden Boy) exposed to 100 micromolar cadmium sulfate produced metal-({gamma}EC){sub n}G peptide complexes containing acid-labile sulfur. The properties of the complexes resemble those of the cadmium-({gamma}EC){sub n}G peptide complexes from Schizo-saccharomyces pombe and Candida glabrata known to contain a cadmium sulfide crystallite core. The crystallite is stabilized by a sheath of peptides of general structure ({gamma}Glu-Cys){sub n}-Gly. The cadmium-peptide complexes of tomato contained predominantly peptides of n{sub 3}, n{sub 4}, and n{sub 5}. Spectroscopic analyses indicated that the tomato cadmium-sulfide-peptide complex contained CdS crystallite core particles smaller than 2.0 nanometers in diameter.

  20. Effects of diallyl sulfide and zinc on testicular steroidogenesis in cadmium-treated male rats.

    PubMed

    Sadik, Nermin A H

    2008-01-01

    Cadmium (Cd) is one of the environmental pollutants that affect various tissues and organs including testis. Harmful effect of cadmium on testis is known to be germ cell degeneration and impairment of testicular steroidogenesis. In the present study, the effect of diallyl sulfide (DAS), a sulfur-containing volatile compound present in garlic, and zinc (Zn) was investigated on cadmium-induced testicular toxicity in rats. Male adult Wistar rats treated with cadmium (2.5 mg/kg body wt, five times a week for 4 weeks) showed decreased body weight, paired testicular weight, relative testicular weight, serum testosterone, luteinizing hormone, follicle-stimulating hormone, and testicular total antioxidant capacity (TAC) and protein levels. Testicular steroidogenic enzymes, such as 3beta-hydroxysteroid dehydrogenase (3beta-HSD) and 17beta-hydroxysteroid dehydrogenase (17beta-HSD), and marker enzymes, such as sorbitol dehydrogenase (SDH), lactate dehydrogenase (LDH), acid phosphatase (ACP), alkaline phosphatase (ALP), and glucose-6-phosphate dehydrogenase (G6PD), showed a significant decrease in activities whereas that of gamma-glutamyl transferase was significantly increased after cadmium exposure. The results have revealed that concurrent treatment with DAS or zinc restored key steroidogenic enzymes, SDH, LDH, and G6PD and increased testicular weight significantly. DAS restored the TAC level and increased testosterone level and relative testicular weight significantly. Zinc restored testicular protein level and body weight. It can be concluded that cadmium causes testicular toxicity and inhibits androgen production in adult male rats probably by affecting pituitary gonadotrophins and that concurrent administration of DAS or zinc provides protection against cadmium-induced testicular toxicity.

  1. Synthesis and Characterization of Cadmium Sulfide Nanoparticles by Chemical Precipitation Method.

    PubMed

    Devi, R Aruna; Latha, M; Velumani, S; Oza, Goldie; Reyes-Figueroa, P; Rohini, M; Becerril-Juarez, I G; Lee, Jae-Hyeong; Yi, Junsin

    2015-11-01

    Cadmium sulfide (CdS) nanoparticles were synthesized by chemical precipitation method using cadmium chloride (CdCl2), sodium sulfide (Na2S) and water as a solvent by varying temperatures from 20-80 degrees C. The nanoparticles were characterized by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), High-resolution transmission electron microscopy (HR-TEM) and UV-Visible spectroscopy. XRD pattern revealed cubic crystal structure for all the synthesized CdS nanoparticles. Raman spectra showed first and second order longitudinal optical (LO) phonon vibrational modes of CdS. The size of CdS nanoparticles was found to be in the range of 15-80 nm by FE-SEM analysis, in all cases. The atomic percentage of cadmium and sulfur was confirmed to be 1:1 from EDS analysis. TEM micrograph depicts the spherical shape of the particles and the size is in the range of 15-85 nm while HR-TEM images of CdS nanoparticles exhibit well-resolved lattice fringes of the cubic structure of CdS. The optical properties of CdS were examined by UV-Visible spectroscopy which showed variation in absorption band from 460-480 nm. The band gap was calculated from the absorption edge and found to be in the range of 3.2-3.5 eV which is greater than the bulk CdS.

  2. Resonant photoactivation of cadmium sulfide and its effect on the surface chemical activity

    NASA Astrophysics Data System (ADS)

    Giberti, Alessio; Fabbri, Barbara; Gaiardo, Andrea; Guidi, Vincenzo; Malagù, Cesare

    2014-06-01

    Photo-enhanced surface chemical activity of cadmium sulfide gives rise to a wide class of surface-dependent phenomena, such as heterogeneous photocatalysis, chemoresistivity, and chemiluminescence, which have several technological and scientific applications. In this work, the photochemical properties of nanostructured cadmium sulfide films are investigated by means of electrical conductance measurements in controlled atmosphere, while irradiated by light of wavelengths ranging from 400 to 645 nm. Chemisorption of benzene, carbon monoxide, methane, ethanol, and hydrogen sulfide onto CdS surface has been analyzed as a function of the wavelength, in a gas concentration range of the order of parts per million. It resulted that the increase of photoconductance with gas adsorption is resonant with the bandgap energy. It turns out that this resonant enhancement of the surface chemical activity can be of advantage for all the optical and chemical mechanisms that depend upon it. An interpretation of these results, in terms of electronic optical transitions and Fermi level shift induced by light, is proposed.

  3. The static structure and dynamics of cadmium sulfide nanoparticles within poly(styrene-block-isoprene) diblock copolymer melts

    DOE PAGES

    Jang, Woo -Sik; Koo, Peter; Bryson, Kyle; ...

    2015-12-20

    Here, the static structure and dynamic behavior of cadmium sulfide nanoparticles suspended in block copolymer matrix are investigated using transmission electron microscopy, small-angle X-ray scattering, and X-ray photon correlation spectroscopy. The transmission electron micro- scopy study shows that cadmium sulfide nanoparticles are preferentially segregated within the polyisoprene domain of a poly(styrene-block-isoprene) diblock copolymer. For the dynamics study, X-ray photon correlation spectroscopy captures the relaxation process of cadmium sulfide nanoparticles. The measured characteristic relaxation time reveals that the observed dynamics are hyperdiffusive. The characteristic velocity and corresponding activation energy, which are hallmarks of a hyperdiffusive system, are determined from the relationshipmore » between the characteristic relaxation time and the wavevector.« less

  4. The static structure and dynamics of cadmium sulfide nanoparticles within poly(styrene-block-isoprene) diblock copolymer melts

    SciTech Connect

    Jang, Woo -Sik; Koo, Peter; Bryson, Kyle; Narayanan, Suresh; Sandy, Alec R.; Russell, Thomas P.; Mochrie, Simon G.

    2015-12-20

    Here, the static structure and dynamic behavior of cadmium sulfide nanoparticles suspended in block copolymer matrix are investigated using transmission electron microscopy, small-angle X-ray scattering, and X-ray photon correlation spectroscopy. The transmission electron micro- scopy study shows that cadmium sulfide nanoparticles are preferentially segregated within the polyisoprene domain of a poly(styrene-block-isoprene) diblock copolymer. For the dynamics study, X-ray photon correlation spectroscopy captures the relaxation process of cadmium sulfide nanoparticles. The measured characteristic relaxation time reveals that the observed dynamics are hyperdiffusive. The characteristic velocity and corresponding activation energy, which are hallmarks of a hyperdiffusive system, are determined from the relationship between the characteristic relaxation time and the wavevector.

  5. Cadmium sulfide nanocluster-based electrochemical stripping detection of DNA hybridization.

    PubMed

    Zhu, Ningning; Zhang, Aiping; He, Pingang; Fang, Yuzhi

    2003-03-01

    A novel, sensitive electrochemical DNA hybridization detection assay, using cadmium sulfide (CdS) nanoclusters as the oligonucleotide labeling tag, is described. The assay relies on the hybridization of the target DNA with the CdS nanocluster oligonucleotide DNA probe, followed by the dissolution of the CdS nanoclusters anchored on the hybrids and the indirect determination of the dissolved cadmium ions by sensitive anodic stripping voltammetry (ASV) at a mercury-coated glassy carbon electrode (GCE). The results showed that only a complementary sequence could form a double-stranded dsDNA-CdS with the DNA probe and give an obvious electrochemical response. A three-base mismatch sequence and non-complementary sequence had negligible response. The combination of the large number of cadmium ions released from each dsDNA hybrid with the remarkable sensitivity of the electrochemical stripping analysis for cadmium at mercury-film GCE allows detection at levels as low as 0.2 pmol L(-1) of the complementary sequence of DNA.

  6. Synthesis and characterization of luminescent cadmium selenide/zinc selenide/zinc sulfide cholinomimetic quantum dots.

    PubMed

    Gégout, Claire; McAtee, Maria L; Bennett, Nichole M; Viranga Tillekeratne, L M; Kirchhoff, Jon R

    2012-08-07

    Luminescent quantum dots conjugated with highly selective molecular recognition ligands are widely used for targeting and imaging biological structures. In this paper, water soluble cholinomimetic cadmium selenide (core), zinc selenide/zinc sulfide (shell) quantum dots were synthesized for targeting cholinergic sites. Cholinomimetic specificity was incorporated by conjugation of the quantum dots to an aminated analogue of hemicholinium-15, a well known competitive inhibitor of the high affinity choline uptake transporter. Detailed evaluation of the nanocrystal synthesis and characterization of the final product was conducted by (1)H and (31)P NMR, absorption and emission spectroscopy, as well as transmission electron microscopy.

  7. Some aspects of optical feedback with cadmium sulfide and related photoconductors. [for extended frequency response

    NASA Technical Reports Server (NTRS)

    Katzberg, S. J.

    1974-01-01

    A primary limitation of many solid state photoconductors used in electro-optical systems is their slow response in converting varying light intensities into electrical signals. An optical feedback technique is presented which can extend the frequency response of systems that use these detectors by orders of magnitude without adversely affecting overall signal-to-noise ratio performance. The technique is analyzed to predict the improvement possible and a system is implemented using cadmium sulfide to demonstrate the effectiveness of the technique and the validity of the analysis.

  8. Optical and electrical properties of inverted emulsions based on sodium bis(2-ethylhexyl) sulfosuccinate containing cadmium sulfide particles

    NASA Astrophysics Data System (ADS)

    Fedyaeva, O. A.; Poshelyuzhnaya, E. G.; Shubenkova, E. G.; Trenikhin, M. V.

    2017-03-01

    The optical and electrical properties of inverted emulsions based on sodium bis(2-ethylhexyl) sulfosuccinate (AOT) containing nanoparticles of cadmium sulfide are studied. The particle size of the synthesized samples is determined from UV spectroscopy data. The state of solubilized water in invert emulsions is found to change in the presence of cadmium sulfide due to the formation of aqua complexes. The shape of AOT micelles and the structures formed by drying the invert AOT emulsions are shown to be affected by the degree of hydration and the solubilization of CdS particles.

  9. Chronic effect of cadmium in sediments on colonization by benthic marine organisms: An evaluation of the role of interstitial cadmium and acid-volatile sulfide in biological availability

    SciTech Connect

    Hansen, D.J.; Berry, W.J.; Benyi, S.J.; Mahony, J.D.; Corbin, J.M.; Pratt, S.D.; Toro, D.M. di |; Abel, M.B.

    1996-12-01

    The role of interstitial cadmium and acid-volatile sulfide (AVS) in controlling the bioavailability of sediment-associated metal was examined using the chronic saltwater benthic colonization test. Sediments were spiked to achieve nominal cadmium/AVS molar ratios of 0.0 (control), 0.1, 0.8, and 3.0 in this 118-d test. Oxidation of AVS in the surficial 2.4 cm within 2 to 4 weeks resulted in sulfide profiles similar to those occurring naturally in local sediments. In the nominal 0.1 cadmium/AVS treatment measured simultaneously extracted metal (SEM{sub Cd}) was always less than AVS. Interstitial cadmium concentrations were less than those likely to cause biological effects. No significant biological effects were detected. In the nominal 0.8 cadmium/AVS treatment, measured SEM{sub Cd} commonly exceeded AVS in the surficial 2.4 cm of sediment. Interstitial cadmium concentrations were of likely toxicological significance to highly sensitive species. Shifts in the presence or absence over all taxa, and fewer macrobenthic polychaetes (Mediomastus ambiseta, Streblospio benedicti, and Podarke obscurea) and unidentified meiofaunal nematodes, were observed. In the nominal 3.0 cadmium/AVS treatment, concentrations of SEM{sub Cd} were always greater than AVS throughout the sediment column. Interstitial cadmium ranged from 28,000 to 174,000 {micro}g/L. In addition to the effects above, the sediments were colonized by fewer macrobenthic species, polychaete species, and harpacticoids; had lower densities of diatoms; lacked bivalve molluscs; and exhibited other impacts. Over all treatments, the observed biological responses were consistent with SEM{sub Cd}/AVS ratios in surficial sediments and interstitial water cadmium concentrations.

  10. Rectification effect in poly- p-xylylene-cadmium sulfide graded nanocomposites

    NASA Astrophysics Data System (ADS)

    Morozov, P. V.; Grigor'ev, E. I.; Zav'yalov, S. A.; Chvalun, S. N.

    2012-11-01

    The hybrid poly- p-xylylene-cadmium sulfide nanocomposites characterized by gradients of concentrations and sizes of CdS nanoparticles along the lines of an applied electric field have been synthesized using the vapor deposition polymerization in an inhomogeneous electric field. The maximum concentration of cadmium sulfide can exceed 10 vol %, while the average effective sizes of the nanoparticles depend on the concentration and do not exceed 5 nm. The synthesized thin-film nanocomposites exhibit a quantum confinement effect. According to the estimates obtained from the shift of the absorption band edge, the radius of nanoparticles is 2.7 nm near the negative electrode and 3.5 nm near the positive electrode. It has been found that the sample formed in an electric field of 10 kV/cm manifests a rectification effect, which can be associated with the gradient of nanoparticle sizes. The measurements of current-voltage characteristics and photoconductivity have demonstrated that the synthesized samples possess high photoconductivity. The photocurrent in the sample prepared in an electric field of 10 kV/cm can exceed the dark current by two orders of magnitude, and the rectification effect in this case disappears.

  11. Morphology and thermal studies of zinc sulfide and cadmium sulfide nanoparticles in polyvinyl alcohol matrix

    NASA Astrophysics Data System (ADS)

    Osuntokun, Jejenija; Ajibade, Peter A.

    2016-09-01

    Zn(II) and Cd(II) metal complexes of 1-cyano-1-carboethoxyethylene-2,2-dithiolato-κS,S'-bis(N,N-dimethylthiourea-κS) have been synthesized and characterized with analytical and spectroscopic techniques. The complexes were thermolysed in hexadecylamine at 200 °C to prepare ZnS and CdS nanoparticles. The nanoparticles were characterized with scanning electron microscope (SEM), transmission electron microscope (TEM), and powder X-ray diffraction (p-XRD). TEM images showed spherically shaped nanoparticles, whose sizes are in the range 4.33-7.21 nm for ZnS and 4.95-7.7 nm CdS respectively and XRD confirmed cubic crystalline phases for the nanoparticles. The optical band gap energy evaluated from the absorption spectra are 2.88 eV (430 nm) and 2.81 eV (440 nm) for the ZnS and CdS nanoparticles respectively. The as-prepared metal sulfide nanoparticles were further incorporated into polyvinyl alcohol (PVA) to give ZnS/PVA and CdS/PVA composites. The polymer nanocomposites were studied to investigate their morphology and thermal properties relative to the pure PVA. XRD diffractions indicated that the crystalline phases of the nanoparticles and the sizes in PVA matrices remained unaltered. Infra-red spectra studies revealed interactions between the PVA and the metal sulfide nanoparticles and TGA studies show that the ZnS/PVA and CdS/PVA nanocomposites exhibit better thermal stability than the pure PVA.

  12. Aerobic transformation of cadmium through metal sulfide biosynthesis in photosynthetic microorganisms

    PubMed Central

    2013-01-01

    Background Cadmium is a non-essential metal that is toxic because of its interference with essential metals such as iron, calcium and zinc causing numerous detrimental metabolic and cellular effects. The amount of this metal in the environment has increased dramatically since the advent of the industrial age as a result of mining activities, the use of fertilizers and sewage sludge in farming, and discharges from manufacturing activities. The metal bioremediation utility of phototrophic microbes has been demonstrated through their ability to detoxify Hg(II) into HgS under aerobic conditions. Metal sulfides are generally very insoluble and therefore, biologically unavailable. Results When Cd(II) was exposed to cells it was bioconverted into CdS by the green alga Chlamydomonas reinhardtii, the red alga Cyanidioschyzon merolae, and the cyanobacterium, Synechoccocus leopoliensis. Supplementation of the two eukaryotic algae with extra sulfate, but not sulfite or cysteine, increased their cadmium tolerances as well as their abilities to produce CdS, indicating an involvement of sulfate assimilation in the detoxification process. However, the combined activities of extracted serine acetyl-transferase (SAT) and O-acetylserine(thiol)lyase (OASTL) used to monitor sulfate assimilation, was not significantly elevated during cell treatments that favored sulfide biosynthesis. It is possible that the prolonged incubation of the experiments occurring over two days could have compensated for the low rates of sulfate assimilation. This was also the case for S. leopoliensis where sulfite and cysteine as well as sulfate supplementation enhanced CdS synthesis. In general, conditions that increased cadmium sulfide production also resulted in elevated cysteine desulfhydrase activities, strongly suggesting that cysteine is the direct source of sulfur for CdS synthesis. Conclusions Cadmium(II) tolerance and CdS formation were significantly enhanced by sulfate supplementation, thus

  13. Aerobic transformation of cadmium through metal sulfide biosynthesis in photosynthetic microorganisms.

    PubMed

    Edwards, Chad D; Beatty, Joseph C; Loiselle, Jacqueline B R; Vlassov, Katya A; Lefebvre, Daniel D

    2013-07-15

    Cadmium is a non-essential metal that is toxic because of its interference with essential metals such as iron, calcium and zinc causing numerous detrimental metabolic and cellular effects. The amount of this metal in the environment has increased dramatically since the advent of the industrial age as a result of mining activities, the use of fertilizers and sewage sludge in farming, and discharges from manufacturing activities. The metal bioremediation utility of phototrophic microbes has been demonstrated through their ability to detoxify Hg(II) into HgS under aerobic conditions. Metal sulfides are generally very insoluble and therefore, biologically unavailable. When Cd(II) was exposed to cells it was bioconverted into CdS by the green alga Chlamydomonas reinhardtii, the red alga Cyanidioschyzon merolae, and the cyanobacterium, Synechoccocus leopoliensis. Supplementation of the two eukaryotic algae with extra sulfate, but not sulfite or cysteine, increased their cadmium tolerances as well as their abilities to produce CdS, indicating an involvement of sulfate assimilation in the detoxification process. However, the combined activities of extracted serine acetyl-transferase (SAT) and O-acetylserine(thiol)lyase (OASTL) used to monitor sulfate assimilation, was not significantly elevated during cell treatments that favored sulfide biosynthesis. It is possible that the prolonged incubation of the experiments occurring over two days could have compensated for the low rates of sulfate assimilation. This was also the case for S. leopoliensis where sulfite and cysteine as well as sulfate supplementation enhanced CdS synthesis. In general, conditions that increased cadmium sulfide production also resulted in elevated cysteine desulfhydrase activities, strongly suggesting that cysteine is the direct source of sulfur for CdS synthesis. Cadmium(II) tolerance and CdS formation were significantly enhanced by sulfate supplementation, thus indicating that algae and cyanobacteria

  14. Studies of Sputtered Cadmium Telluride and Cadmium Selenide Solar Cells

    NASA Astrophysics Data System (ADS)

    Kwon, Dohyoung

    CdTe has recently become the most commercially successful polycrystalline thinfilm solar module material. Its low cost, large-area solar module is reshaping the silicondominated solar panel market; however, CdTe has much room to improve and thus more fundamental understanding is needed. Current thin film solar cell research is focused on two areas: One is identifying loss mechanisms and understanding the polycrystalline nature of single junction device to improve device performance. Another is searching for new materials and fabricating tandem solar cells. In this study, along with other people's work to improve the efficiency of CdTe solar module, I studied loss mechanism and growth mode of CdTe solar cells to have fundamental understanding of polycrystalline films. In addition to that, in an effort to make tandem solar cells, I fabricated and characterized CdSe solar cells, which is considered as an ideal candidate for the top cell with its band gap of 1.7 eV. This dissertation is designed to show similarities and differences between CdTe and CdSe solar cells, side by side. After the introduction (Chapter1), I will review the physical properties of CdTe and CdSe solar cells (Chapter 2). Two primary tools to study defects and surface morphology were photoluminescence (PL) and atomic force microscopy (AFM). PL showed information on the crystallinity and defects of CdTe and CdSe films before and after annealing.(Chapter 3). AFM measurements and their analysis using scaling theory revealed information on the growth modes of CdTe and CdSe films.(Chapter 4). With the goal of exploring suitability for tandem structures with ˜1.7 eV top cell and ˜1.1 eV bottom cell, I fabricated and characterized single-junction CdSe devices. (Chapter 5) In addition, for the bottom cell I fabricated HgCdTe cells with Eg˜1.1 eV. Single junction HgCdTe and two-terminal CdTe/HgCdTe tandem solar cells were fabricated and characterized. (Chapter 5)

  15. Charge Carrier Processes in Photovoltaic Materials and Devices: Lead Sulfide Quantum Dots and Cadmium Telluride

    NASA Astrophysics Data System (ADS)

    Roland, Paul

    Charge separation, transport, and recombination represent fundamental processes for electrons and holes in semiconductor photovoltaic devices. Here, two distinct materials systems, based on lead sulfide quantum dots and on polycrystalline cadmium telluride, are investigated to advance the understanding of their fundamental nature for insights into the material science necessary to improve the technologies. Lead sulfide quantum dots QDs have been of growing interest in photovoltaics, having recently produced devices exceeding 10% conversion efficiency. Carrier transport via hopping through the quantum dot thin films is not only a function of inter-QD distance, but of the QD size and dielectric media of the surrounding materials. By conducting temperature dependent transmission, photoluminescence, and time resolved photoluminescence measurements, we gain insight into photoluminescence quenching and size-dependent carrier transport through QD ensembles. Turning to commercially relevant cadmium telluride (CdTe), we explore the high concentrations of self-compensating defects (donors and acceptors) in polycrystalline thin films via photoluminescence from recombination at defect sites. Low temperature (25 K) photoluminescence measurements of CdTe reveal numerous radiative transitions due to exciton, trap assisted, and donor-acceptor pair recombination events linked with various defect states. Here we explore the difference between films deposited via close space sublimation (CSS) and radio frequency magnetron sputtering, both as-grown and following a cadmium chloride treatment. The as-grown CSS films exhibited a strong donor-acceptor pair transition associated with deep defect states. Constructing photoluminescence spectra as a function of time from time-resolved photoluminescence data, we report on the temporal evolution of this donor-acceptor transition. Having gained insight into the cadmium telluride film quality from low temperature photoluminescence measurements

  16. Synthesis of cadmium sulfide in situ in reverse micelles and in hydrocarbon gels

    SciTech Connect

    Petit, C.; Pileni, M.P.

    1988-04-21

    The synthesis in situ of cadmium sulfide semiconductors in AOT reverse micelles produces smaller and more monodispersed particles than are obtained in Triton reverse micelles or in aqueous solution. When gelatine is added to the previous solution, the semiconductor is entrapped in a hydrocarbon gel and it size remains the same as that obtained in reverse micelles. The size of the sulfite cadmium aggregate formed in AOT hydrocarbon gels is similar to that obtained under similar conditions in AOT reverse micelles. AOT surfactant can play the role of stabilizing agent. However, a more efficient stabilization is obtained by adding to AOT reverse micelles another stabilizing agent such as sodium hexametaphosphate. The crystallite size is strongly dependent on the ratio of the cadmium and sulfur ions, defined by x = (Cd/sup 2 +/)/(S/sup 2 -//. The yield of reduced viologen obtained by CdS irradiation in AOT reverse micelles is 15 times more efficient than that formed in aqueous solutions whereas it is only three times more in hydrocarbon gels.

  17. A sonochemical method for the preparation of cadmium sulfide and cadmium selenide nanoparticles in aqueous solutions.

    PubMed

    Kristl, Matjaz; Ban, Irena; Danc, Anita; Danc, Valerija; Drofenik, Miha

    2010-06-01

    Sonochemistry is a branch of chemistry where sound energy in the form of ultrasound is used to influence the course of reactions. A short-term, local increase in temperature occurs when the solutions and suspensions are irradiated by ultrasound. This happens because the substance absorbs the ultrasound waves. The purpose of this research was the synthesis of CdS and CdSe nanoparticles. We used cadmium sulfate hydrate (CdSO(4).8/3H(2)O), elemental S and Se. Aqueous solutions of NaOH, Na(2)SO(3) and EDTA were used as the solvents. During the syntheses, we used a direct immersion ultrasound probe by vibracell. The device operates with a constant frequency of 20 kHz, with the possibility to change the amplitude and with it the input of energy to the time unit. The products were characterized by X-ray powder diffraction (XRD), thermal analyses (TGA, SDTA) and TEM analyses.

  18. Theoretical simulation of performances in CIGS thin-film solar cells with cadmium-free buffer layer

    NASA Astrophysics Data System (ADS)

    Luo, Kang; Sun, Yulin; Zhou, Liyu; Wang, Fang; Wu, Fang

    2017-08-01

    Copper indium gallium selenium (CIGS) thin film solar cells have become one of the hottest topics in solar energy due to their high photoelectric transformation efficiency. To real applications, CIGS thin film is covered by the buffer layer and absorption layer. Traditionally, cadmium sulfide (CdS) is inserted into the middle of the window layer (ZnO) and absorption layer (CIGS) as a buffer layer. However, the application of the GIGS/CdS thin film solar cells has been limited because of the environmental pollution resulting from the toxic cadmium atom. Although zinc sulfide (ZnS) has been proposed to be one of the candidates, the performance of such battery cells has not been investigated. Here, in this paper, we systematically study the possibility of using zinc sulfide (ZnS) as a buffer layer. By including the effects of thickness, concentration of a buffer layer, intrinsic layer and the absorbing layer, we find that photoelectric transformation efficiency of ZnO/ZnS(n)/CIGS(i)/CIGS(p) solar cell is about 17.22%, which is qualified as a commercial solar cell. Moreover, we also find that the open-circuit voltage is ∼0.60 V, the short-circuit current is ∼36.99 mA/cm2 and the filled factor is ∼77.44%. Therefore, our results suggest that zinc sulfide may be the potential candidate of CdS as a buffer layer. Project supported by the NSF of Jiangsu Province (No. BK20131420), the Postgraduate Innovation Project of Jiangsu Province (No. KYLX15_0926), and the NJFU Outstanding Young Scholars Funding.

  19. Chemical bath deposition of cadmium sulfide on graphene-coated flexible glass substrate

    SciTech Connect

    Seo, Won-Oh; Jung, Younghun; Kim, Jihyun; Kim, Jiwan; Kim, Donghwan

    2014-03-31

    We demonstrate a flexible structure of cadmium sulfide (CdS) on graphene-coated glass substrate, where CdS was deposited by the chemical bath deposition method on defective tri-layer graphene. The defects in graphene, confirmed by micro-Raman spectroscopy, were created by a ultra-violet treatment with varying exposure time from 10 to 60 min. The number of defect sites in the graphene as a seed layer was related to the quality of the CdS thin films determined from the results from X-ray diffraction, optical transmittance, scanning electron microscopy, and room temperature micro-photoluminescence. Our film-on-substrate structure of CdS-graphene-on-glass was maintained up to a tensile strain of 0.3%, where graphene with a high failure strain was employed as a transparent conductive layer.

  20. The synthesis of cadmium sulfide nanoplatelets using a novel continuous flow sonochemical reactor

    SciTech Connect

    Palanisamy, Barath; Paul, Brian; Chang, Chih -hung

    2015-01-21

    A continuous flow sonochemical reactor was developed capable of producing metastable cadmium sulfide (CdS) nanoplatelets with thicknesses at or below 10 nm. The continuous flow sonochemical reactor included the passive in-line micromixing of reagents prior to sonochemical reaction. Synthesis results were compared with those from reactors involving batch conventional heating and batch ultrasound-induced heating. The continuous sonochemical synthesis was found to result in high aspect ratio hexagonal platelets of CdS possessing cubic crystal structures with thicknesses well below 10 nm. The unique shape and crystal structure of the nanoplatelets are suggestive of high localized temperatures within the sonochemical process. As a result, the particle size uniformity and product throughput are much higher for the continuous sonochemical process in comparison to the batch sonochemical process and conventional synthesis processes.

  1. The synthesis of cadmium sulfide nanoplatelets using a novel continuous flow sonochemical reactor

    DOE PAGES

    Palanisamy, Barath; Paul, Brian; Chang, Chih -hung

    2015-01-21

    A continuous flow sonochemical reactor was developed capable of producing metastable cadmium sulfide (CdS) nanoplatelets with thicknesses at or below 10 nm. The continuous flow sonochemical reactor included the passive in-line micromixing of reagents prior to sonochemical reaction. Synthesis results were compared with those from reactors involving batch conventional heating and batch ultrasound-induced heating. The continuous sonochemical synthesis was found to result in high aspect ratio hexagonal platelets of CdS possessing cubic crystal structures with thicknesses well below 10 nm. The unique shape and crystal structure of the nanoplatelets are suggestive of high localized temperatures within the sonochemical process. Asmore » a result, the particle size uniformity and product throughput are much higher for the continuous sonochemical process in comparison to the batch sonochemical process and conventional synthesis processes.« less

  2. Synthesis of cadmium sulfide Q particles in water-in-CO{sub 2} microemulsions

    SciTech Connect

    Holmes, J.D.; Bhargava, P.A.; Korgel, B.A.; Johnston, K.P.

    1999-09-28

    Semiconductor nanoparticles of cadmium sulfide were synthesized in ammonium perfluoropolyether (PFPE-NH{sub 4}) stabilized water-in-CO{sub 2} microemulsions. The particle size was tuned by varying the water-to-surfactant molar ratio ({omega}{sub 0}): {omega}{sub 0} ratios of 5 and 10 yielded nanocrystals with exciton energies of 3.86 and 3.09 eV, corresponding to mean particle radii of 0.9 and 1.8 nm, respectively. These exciton energies are significantly higher than the bulk band gap energy for CdS (2.45 eV) due to quantum confinement effects. Effectively, {omega}{sub 0} controls the size of the compartmentalized water droplets in which the particles grow.

  3. The Potential Application of Raw Cadmium Sulfide Nanoparticles as CT Photographic Developer

    NASA Astrophysics Data System (ADS)

    Wu, Qiang; Huang, Lingxin; Li, Zhan; An, Wenzhen; Liu, Dan; Lin, Jin; Tian, Longlong; Wang, Xinling; Liu, Bo; Qi, Wei; Wu, Wangsuo

    2016-04-01

    With the development of science and technology, new applications about nanoparticles should be explored to achieve full-scale knowledge. Therefore, in this work, the toxicity and potential application of raw cadmium sulfide nanoparticles (CdS) in vivo were further studied through ICP-OES and CTs. Surprisingly, CdS exhibited an excellent photographic property, except for finding the accumulation of CdS in the lungs, liver, spleen, and kidney with a strong dependence on time; it is also found that there were a significant uptake in the pancreas for an obvious CT imaging. And the following investigations showed that the raw CdS could damage the tissues accumulating nanoparticles. Through this work, it can be seen that the raw CdS being modified might be an excellent photographic developer for detecting cancers or other diseases.

  4. Self-organization of cadmium sulfide nanoparticles on the macroscopic scale

    NASA Astrophysics Data System (ADS)

    Rempel, Andrej A.; Kozhevnikova, Natalia S.; van den Berghe, Sven; van Renterghem, Wouter; Leenaers, Ann J. G.

    2005-06-01

    A self-organization of chemical bath deposited cadmium sulfide colloidal particles into well shaped hexagonal prisms of nearly the same size in a micrometer range is found. The self-organization phenomenon itself and the size of resulting prisms depend on the chemical affinity of the deposition reaction. In spite of the nearly perfect shape, the inner structure of the CdS colloidal crystals is highly disordered and has at least two hierarchy levels. On the scale of scanning electron microscopy, the loose and disordered microstructure of the colloidal crystals consists of nonuniformly shaped coagulates, with sizes between 150 and 250 nm. Transmission electron microscopy shows that the coagulates are polycrystals with large angle boundaries between nonuniformly shaped grains with an average size of 7 +/- 2 nm.

  5. Synthesis and interface structures of zinc sulfide sheathed zinc-cadmium nanowire heterojunctions.

    PubMed

    Shen, Guozhen; Bando, Yoshio; Gao, Yihua; Golberg, Dmitri

    2006-07-27

    Zinc sulfide (ZnS) sheathed zinc (Zn)-cadmium (Cd) nanowire heterojunctions have been prepared by thermal evaporating of ZnS and CdS powders in a vertical induction furnace at 1200 degrees C. Studies found that both the Zn and Cd subnanowires, within a single nanoheterojunction, are single-crystallines with the growth directions perpendicular to the [210] plane, whereas the sheathed ZnS is polycrystalline with a thickness of ca. 5 nm. The Zn/Cd interface structure in the ZnS sheathed Zn-Cd nanowire heterojunctions was thoroughly experimentally studied by high-resolution transmission electron microscopy and theoretically studied using a near-coincidence site lattice (NCSL) concept. The results show that the Cd and Zn have a crystalline orientation relationship as [0001]Zn//[0001]Cd, (10(-)10)Zn//(10(-)10)Cd, (01(-)10)Zn//(01(-)10)Cd, and ((-)1100)Zn//((-)1100)Cd.

  6. Imaging characteristics of zinc sulfide shell, cadmium telluride core quantum dots.

    PubMed

    Daneshvar, Hamid; Nelms, Jennifer; Muhammad, Osman; Jackson, Heather; Tkach, Jean; Davros, William; Peterson, Todd; Vogelbaum, Michael A; Bruchez, Marcel P; Toms, Steven A

    2008-02-01

    Quantum dots are optical nanocrystals whose in vitro and in vivo use in molecular imaging is expanding rapidly. In comparison with organic fluorophores, quantum dots exhibit desirable properties, such as multiwavelength fluorescence emission, excellent brightness and resistance to photobleaching. Their electron-dense, metallic cores suggest utility in other clinical imaging modalities. Core-shell zinc sulfide-cadmium telluride quantum dots were studied by magnetic resonance and computed tomography phantoms. Quantum dots were also injected into rat brain, as well as intravenously, using convection-enhanced delivery, prior to animal imaging. Computed tomography studies suggest that current formulations of quantum dots might be imaged in vivo in animals. Used in conjunction with optical imaging techniques, quantum dots have the potential to function as multimodal imaging platforms in vivo. The ability to detect an optical nanoparticle preoperatively with clinical imaging modality offers a distinct advantage to clinicians engaged in image-guided surgical applications.

  7. In situ-synthesized cadmium sulfide nanowire photosensor with a parylene passivation layer for chemiluminescent immunoassays.

    PubMed

    Im, Ju-Hee; Kim, Hong-Rae; An, Byoung-Gi; Chang, Young Wook; Kang, Min-Jung; Lee, Tae-Geol; Son, Jin Gyeng; Park, Jae-Gwan; Pyun, Jae-Chul

    2017-06-15

    The direct in situ synthesis of cadmium sulfide (CdS) nanowires (NWs) was presented by direct synthesis of CdS NWs on the gold surface of an interdigitated electrode (IDE). In this work, we investigated the effect of a strong oxidant on the surfaces of the CdS NWs using X-ray photoelectron spectroscopy, transmission electron microscopy, and time-of-flight secondary ion mass spectrometry. We also fabricated a parylene-C film as a surface passivation layer for in situ-synthesized CdS NW photosensors and investigated the influence of the parylene-C passivation layer on the photoresponse during the coating of parylene-C under vacuum using a quartz crystal microbalance and a photoanalyzer. Finally, we used the in situ-synthesized CdS NW photosensor with the parylene-C passivation layer to detect the chemiluminescence of horseradish peroxidase and luminol and applied it to medical detection of carcinoembryonic antigen.

  8. The Potential Application of Raw Cadmium Sulfide Nanoparticles as CT Photographic Developer.

    PubMed

    Wu, Qiang; Huang, Lingxin; Li, Zhan; An, Wenzhen; Liu, Dan; Lin, Jin; Tian, Longlong; Wang, Xinling; Liu, Bo; Qi, Wei; Wu, Wangsuo

    2016-12-01

    With the development of science and technology, new applications about nanoparticles should be explored to achieve full-scale knowledge. Therefore, in this work, the toxicity and potential application of raw cadmium sulfide nanoparticles (CdS) in vivo were further studied through ICP-OES and CTs. Surprisingly, CdS exhibited an excellent photographic property, except for finding the accumulation of CdS in the lungs, liver, spleen, and kidney with a strong dependence on time; it is also found that there were a significant uptake in the pancreas for an obvious CT imaging. And the following investigations showed that the raw CdS could damage the tissues accumulating nanoparticles. Through this work, it can be seen that the raw CdS being modified might be an excellent photographic developer for detecting cancers or other diseases.

  9. Effects of Liquid Medium and Ablation Wavelength on the Properties of Cadmium Sulfide Nanoparticles Formed by Pulsed-Laser Ablation.

    PubMed

    García Guillén, Grisel; Zuñiga Ibarra, Veronica Anahi; Mendivil Palma, Maria Isabel; Krishnan, Bindu; Avellaneda Avellaneda, David; Shaji, Sadasivan

    2017-05-05

    Pulsed-laser ablation in liquid (PLAL) is a green synthesis technique to obtain semiconductor nanomaterials in colloidal form. Herein, cadmium sulfide (CdS) nanoparticles were synthesized by the pulsed-laser ablation of a CdS target in different liquid media by using λ=532 and 1064 nm outputs from a pulsed (10 ns, 10 Hz) Nd:YAG laser at different ablation fluence values. The morphology, structure, crystalline phase, elemental composition, optical, and luminescent properties of CdS nanomaterials were analyzed by using transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV/Vis absorption spectroscopy, and fluorescence spectroscopy. By changing the liquid medium and ablation wavelength, CdS nanoparticles with different morphology and size were formed, as demonstrated by using TEM analysis. The crystallinity and chemical states of the ablation products were confirmed by using XRD and XPS analyses. The optical bandgap of the CdS nanoparticles was dependent on the ablation wavelength and the fluence. These nanocolloids presented different green emissions, which implied the presence of several emission centers. CdS nanocolloids in distilled water catalyzed the photocatalytic decay of methylene blue dye under light irradiation from a solar simulator. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Cadmium sulfide/copper sulfide heterojunction cell research. Final report, February 26, 1979-July 15, 1980

    SciTech Connect

    Thornton, J. A.; Cornog, D. G.

    1980-06-30

    Extensive modifications were made to the multi-source deposition apparatus. These include the installation of a larger vacuum chamber on the existing system. The new chamber provides improved inter-source shielding, an improved substrate mounting and heating system, and a vacuum interlock for introducing substrates. CdS resistivity control by both In doping and off-stoichiometric deposition has been investigated. Indium doping has been achieved both by diffusion from a pre-deposited In layer and by using In doped sputtering targets. Resistivities in the range 0.1 to 5 ..cap omega..-cm have been obtained for target doping levels of from 0.1 to 1 at. percent of In. These resistivities were found to be critically dependent on the H/sub 2/S injection rate, apparently because of compensation by Cd vacancies. Off-stoichiometry CdS coatings with solar-illuminated resistivities of about 10/sup 2/ ..cap omega..-cm have been deposited, using a cyclic reactive sputtering process were the H/sub 2/S injection is periodically switched on and off. The Cu/sub x/S deposition process was found to be sensitive to the period of cathode operation prior to coating deposition, probably because of the conditioning of cathode and shield surfaces. All-sputter-deposited Cd(Zn)S/Cu/sub 2/S cells, with Cd(Zn)S layers deposited using a Cd-0.10 Zn target doped with 2 atomic percent In, have yielded efficiencies of approx. 0.4%. All-sputtered cells with efficiencies of approx. 0.6% have been fabricated, using undoped CdS deposited by the pulse injection process. Efficiencies of approx. 1.2% have been achieved for cells with undoped sputter-deposited CdS and CuCl dry processed Cu/sub 2/S.

  11. Luminescent behavior of cadmium sulfide quantum dots for gallic acid estimation.

    PubMed

    Singh, Suman; Garg, Sourav; Chahal, Jitender; Raheja, Khushboo; Singh, Deepak; Singla, M L

    2013-03-22

    Thioglycolic acid capped cadmium sulfide (CdS/T) quantum dots have been synthesized using wet chemistry and their optical behavior has been investigated using UV-visible absorption and fluorescence spectroscopy. The role of the capping agent, sulfide source concentration, pH and temperature has been studied and discussed. Studies showed that alkaline pH leads to a decrease in the size of quantum dots and reflux temperature above 70 °C resulted in red-shift of emission spectra which is due to narrowing of the bandgap. Further, to reduce the toxicity and photochemical instability of quantum dots, the quantum dots have been functionalized with polyethylene glycol (PEG), which resulted in a 20% enhancement of the fluorescence intensity. The application potential of CdS/T-PEG quantum dots was further studied using gallic acid as a model compound. The sensing is based on fluorescence quenching of quantum dots in the presence of gallic acid, and this study showed linearity in the range from 1.3 × 10(-8) to 46.5 × 10(-8) mM, with a detection limit of 3.6 × 10(-8) mM.

  12. Luminescent behavior of cadmium sulfide quantum dots for gallic acid estimation

    NASA Astrophysics Data System (ADS)

    Singh, Suman; Garg, Sourav; Chahal, Jitender; Raheja, Khushboo; Singh, Deepak; Singla, M. L.

    2013-03-01

    Thioglycolic acid capped cadmium sulfide (CdS/T) quantum dots have been synthesized using wet chemistry and their optical behavior has been investigated using UV-visible absorption and fluorescence spectroscopy. The role of the capping agent, sulfide source concentration, pH and temperature has been studied and discussed. Studies showed that alkaline pH leads to a decrease in the size of quantum dots and reflux temperature above 70 °C resulted in red-shift of emission spectra which is due to narrowing of the bandgap. Further, to reduce the toxicity and photochemical instability of quantum dots, the quantum dots have been functionalized with polyethylene glycol (PEG), which resulted in a 20% enhancement of the fluorescence intensity. The application potential of CdS/T-PEG quantum dots was further studied using gallic acid as a model compound. The sensing is based on fluorescence quenching of quantum dots in the presence of gallic acid, and this study showed linearity in the range from 1.3 × 10-8 to 46.5 × 10-8 mM, with a detection limit of 3.6 × 10-8 mM.

  13. Effect of cadmium in sediments on colonization by benthic marine organisms: Role of interstitial cadmium and acid volatile sulfide in bioavailability

    SciTech Connect

    Hansen, D.; Berry, W.; Benyi, S.; Mahony, J.; Corbin, J.; Pratt, S.; Able, M.

    1995-12-31

    The role of interstitial cadmium and acid volatile sulfide (AVS) in controlling the bioavailability of sediment-associated metal was examined using the chronic saltwater benthic colonization test. Sediments were spiked with cadmium to achieve simultaneously extracted metal (SEM)/AVS molar ratios of 0. 0 (control), 0.1, 0.8 and 3.0 in this 118-day test. Oxidation of AVS in the surficial 2.4 cm within two to four weeks resulted in sulfide profiles similar to those occurring naturally in local sediments. In the nominal 0.1 SEM/AVS treatment, measured SEM was always less than AVS. Interstitial cadmium concentrations (< 3--10 {micro}g/L) were below those likely to cause biological effects. No significant biological effects were detected. In the nominal 0.8 SEM/AVS treatment, measured SEM commonly exceeded AVS in the surficial 2.4 cm of sediment. Interstitial cadmium concentrations (24--157 {micro}g/L) were likely of toxicological significance to sensitive species. Shifts were observed in presence/absence of species, and there were fewer macrobenthic polychaetes (Mediomastus ambiseta, Strebloapio benedicti and Podarke obscura) and unidentified meiofaunal nematodes. In the nominal 3.0 SEM/AVS treatment, concentrations of SEM were always greater than AVS throughout the sediment column. Interstitial cadmium ranged from 28,000 to 174,000 {micro}g/L. In addition to the effects above, these sediments were colonized by fewer macrobenthic species, polychaete species and harpacticoids; had lower densities of diatoms; lacked bivalve molluscs and exhibited other impacts. The observed biological responses were consistent with measured SEM/AVS ratios in surficial sediments and interstitial water cadmium concentrations, further supporting their utility in predicting metals bioavailability.

  14. Hydrogen sulfide alleviates cadmium toxicity through regulations of cadmium transport across the plasma and vacuolar membranes in Populus euphratica cells.

    PubMed

    Sun, Jian; Wang, Ruigang; Zhang, Xuan; Yu, Yicheng; Zhao, Rui; Li, Zongyun; Chen, Shaoliang

    2013-04-01

    Hydrogen sulfide (H2S) is emerging as a novel signalling molecule involved in plant growth and responses against abiotic stresses. However, little information is known about its role in cadmium (Cd) detoxification. In the present study, the effects of H2S on Cd toxicity were investigated in Populus euphratica cells using fluorescence imaging technique and a non-invasive vibrating ion-selective microelectrode. Pretreatment with a H2S donor, sodium hydrosulfide (NaHS), significantly mitigated the Cd-induced programmed cell death in P. euphratica cells. The alleviation effect of NaHS was more pronounced at 50-100 μM as compared to low (25 μM) and high doses (200 μM). Under Cd stress, total activities of antioxidant enzymes, such as ascorbate peroxidase, catalase and glutathione reductase, were significantly enhanced in NaHS-treated cells, leading to a decline of H2O2 accumulation and lipid peroxidation. Moreover, NaHS reduced Cd accumulation in the cytoplasm but increased the fraction of Cd in the vacuole. Cd flux profiles revealed that H2S inhibited the Cd influx through the plasma membrane (PM) calcium channels that activated by H2O2. NaHS enhanced Cd influx into the vacuole, and the Cd influx was dependent on the pH gradients across the tonoplast. Taken together, these results suggest that H2S alleviates Cd toxicity via the improvement of antioxidant system and cellular Cd homeostasis. The up-regulation of antioxidant enzymes by H2S reduced the accumulation of H2O2, and thus decreased Cd influx through the H2O2-activated PM calcium channels. The H2S-simulated vacuolar Cd sequestration was presumably due to the activation of tonoplast Cd(2+)/H(+) antiporters. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  15. Surface modification of cadmium sulfide thin film honey comb nanostructures: Effect of in situ tin doping using chemical bath deposition

    NASA Astrophysics Data System (ADS)

    Wilson, K. C.; Basheer Ahamed, M.

    2016-01-01

    Even though nanostructures possess large surface to volume ratio compared to their thin film counterpart, the complicated procedure that demands for the deposition on a substrate kept them back foot in device fabrication techniques. In this work, a honey comb like cadmium sulfide (CdS) thin films nanostructure are deposited on glass substrates using simple chemical bath deposition technique at 65 °C. Energy band gaps, film thickness and shell size of the honey comb nanostructures are successfully controlled using tin (Sn) doping and number of shells per unit area is found to be maximum for 5% Sn doped (in the reaction mixture) sample. X-ray diffraction and optical absorption analysis showed that cadmium sulfide and cadmium hydroxide coexist in the samples. TEM measurements showed that CdS nanostructures are embedded in cadmium hydroxide just like "plum pudding". Persistent photoconductivity measurements of the samples are also carried out. The decay constants found to be increased with increases in Sn doping.

  16. Cadmium solubility in paddy soils: effects of soil oxidation, metal sulfides and competitive ions.

    PubMed

    de Livera, Jennifer; McLaughlin, Mike J; Hettiarachchi, Ganga M; Kirby, Jason K; Beak, Douglas G

    2011-03-15

    Cadmium (Cd) is a non-essential element for human nutrition and is an agricultural soil contaminant. Cadmium solubility in paddy soils affects Cd accumulation in the grain of rice. This is a human health risk, exacerbated by the fact that rice grains are deficient in iron (Fe) and zinc (Zn) for human nutrition. To find ways of limiting this potential risk, we investigated factors influencing Cd solubility relative to Fe and Zn during pre-harvest drainage of paddy soils, in which soil oxidation is accompanied by the grain-filling stage of rice growth. This was simulated in temperature-controlled "reaction cell" experiments by first excluding oxygen to incubate soil suspensions anaerobically, then inducing aerobic conditions. In treatments without sulfur addition, the ratios of Cd:Fe and Cd:Zn in solution increased during the aerobic phase while Cd concentrations were unaffected and the Fe and Zn concentrations decreased. However, in treatments with added sulfur (as sulfate), up to 34 % of sulfur (S) was precipitated as sulfide minerals during the anaerobic phase and the Cd:Fe and Cd:Zn ratios in solution during the aerobic phase were lower than for treatments without S addition. When S was added, Cd solubility decreased whereas Fe and Zn were unaffected. When soil was spiked with Zn the Cd:Zn ratio was lower in solution during the aerobic phase, due to higher Zn concentrations. Decreased Cd:Fe and Cd:Zn ratios during the grain filling stage could potentially limit Cd enrichment in paddy rice grain due to competitive ion effects for root uptake. Copyright © 2010 Elsevier B.V. All rights reserved.

  17. Cadmium Telluride Solar Cells with PEDOT:PSS Back Contact

    NASA Astrophysics Data System (ADS)

    Mount, Michael; Duarte, Fernanda; Paudel, Naba; Yan, Yanfa; Wang, Weining

    Cadmium Telluride (CdTe) solar cell is one of the most promising thin film solar cells and its highest efficiency has reached 21%. To keep improving the efficiency of CdTe solar cells, a few issues need to be addressed, one of which is the back contact. The back contact of CdTe solar cells are mostly Cu-base, and the problem with Cu-based back contact is that Cu diffuses into the grain boundary and into the CdS/CdTe junction, causing degradation problem at high temperature and under illumination. To continue improving the efficiency of CdTe/CdS solar cells, a good ohmic back contact with high work function and long term stability is needed. In this work, we report our studies on the potential of conducting polymer being used as the back contact of CdTe/CdS solar cells. Conducting polymers are good candidates because they have high work functions and high conductivities, are easy to process, and cost less, meeting all the requirements of a good ohmic back contact for CdTe. In our studies, we used poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) with different conductivities and compared them with traditional Cu-based back contact. It was observed that the CdTe solar cell performance improves as the conductivity of the PEDOT:PSS increase, and the efficiency (9.1%) is approaching those with traditional Cu/Au back contact (12.5%). Cadmium Telluride Solar Cells with PEDOT:PSS Back Contact.

  18. Fluorescence modulation of cadmium sulfide quantum dots by azobenzene photochromic switches.

    PubMed

    Javed, Hina; Fatima, Kalsoom; Akhter, Zareen; Nadeem, Muhammad Arif; Siddiq, Muhammad; Iqbal, Azhar

    2016-02-01

    We have investigated the attachment of azobenzene photochromic switches on the modified surface of cadmium sulfide (CdS) quantum dots (QDs). The modification of CdS QDs is done by varying the concentration of the capping agent (mercaptoacetic acid) and NH3 in order to control the size of the QDs. The X-ray diffraction studies revealed that the crystallite size of CdS QDs ranged from 6 to 10 nm. The azobenzene photochromic derivatives bis(4-hydroxybenzene-1-azo)4,4'(1,1' diphenylmethane) (I) and 4,4'-diazenyldibenzoic acid (II) were synthesized and attached with surface-modified CdS QDs to make fluorophore-photochrome CdS-(I) and CdS-(II) dyad assemblies. Upon UV irradiation, the photochromic compounds (I) and (II) undergo a reversible trans-cis isomerization. The photo-induced trans-cis transformation helps to transfer photo-excited electrons from the conduction band of the CdS QDs to the lowest unoccupied molecular orbital of cis isomer of photochromic compounds (I) and (II). As a result, the fluorescence of CdS-(I) and CdS-(II) dyads is suppressed approximately five times compared to bare CdS QDs. The fluorescence modulation in such systems could help to design luminescent probes for bioimaging applications.

  19. Direct electrochemical stripping detection of cystic-fibrosis-related DNA linked through cadmium sulfide quantum dots.

    PubMed

    Marin, Sergio; Merkoçi, Arben

    2009-02-04

    Electrochemical detection of a cadmium sulfide quantum dots (CdS QDs)-DNA complex connected to paramagnetic microbeads (MB) was performed without the need for chemical dissolving. The method is based on dropping 20 microl of CdS QD-DNA-MB suspension on the surface of a screen-printed electrode. It is followed by magnetic collection on the surface of the working electrode and electrochemical detection using square-wave voltammetry (SWV), giving a well-shaped and sensitive analytical signal. A cystic-fibrosis-related DNA sequence was sandwiched between the two DNA probes. One DNA probe is linked via biotin-streptavidin bonding with MB and the other one via thiol groups with the CdS QD used as tags. Nonspecific signals of DNA were minimized using a blocking agent and the results obtained were successfully employed in a model DNA sensor with an interest in future applications in the clinical field. The developed nanoparticle biosensing system may offer numerous opportunities in other fields where fast, low cost and efficient detection of small volume samples is required.

  20. Circular dichroism sensor based on cadmium sulfide quantum dots for chiral identification and detection of penicillamine.

    PubMed

    Ngamdee, Kessarin; Puangmali, Theerapong; Tuntulani, Thawatchai; Ngeontae, Wittaya

    2015-10-22

    A new chemical sensor based on the measuring of circular dichroism signal (CD) was fabricated from cysteamine capped cadmium sulfide quantum dots (Cys-CdS QDs). The chiral-thiol molecules, d-penicillamine (DPA) and l-penicillamine (LPA), were used to evaluate potentials of this sensor. Basically, DPA and LPA provide very low CD signals. However, the CD signals of DPA and LPA can be enhanced in the presence of Cys-CdS QDs. The CD spectra of DPA and LPA exhibited a mirror image profile. Parameters affecting the determination of DPA and LPA were thoroughly investigated in details. Under the optimized condition, the CD signals of DPA and LPA displayed a linear relationship with the concentrations of both enantiomers, ranging from 1 to 35 μM. Detection limits of this sensor were 0.49 and 0.74 μM for DPA and LPA, respectively. To demonstrate a potential application of this sensor, the proposed sensor was used to determine DPA and LPA in real urine samples. It was confirmed that the proposed detection technique was reliable and could be utilized in a broad range of applications. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Cadmium sulfide with tunable morphologies: Preparation and visible-light driven photocatalytic performance

    NASA Astrophysics Data System (ADS)

    Fang, Zhi; Zhang, Liqin; Yang, Tao; Su, Lei; Chou, Kuo-Chih; Hou, Xinmei

    2017-09-01

    Wurtzite cadmium sulfide (CdS) with four kinds of morphologies including dendrites, flowers, multipods and spheres, were tunably prepared using a facile and simple hydrothermal route with an assistance of N,N-dimethylformamide (DMF). The formation mechanism of CdS with different morphologies was discussed based on the phase and microstructure characterization by X-ray diffraction (XRD) and field emission scanning electronic microscopy (FE-SEM) with energy dispersive spectrometer (EDS). The effect of morphology on the photoelectrochemical (PEC) performance was investigated using linear sweep voltammetry (LSV), photocurrent versus irradiation time curve (I-t) and electrochemical impedance spectroscope (EIS). The results show that the dendrite-like CdS exhibits the highest photocurrent density with 0.748 mA/cm2 at 0.253 V. The photodegradation of Rhodamine B (RhB) further proves the dendrite-like CdS possesses excellent photocatalytic (PC) performance, which could be mainly attributed to the unique hyperbranched structure, larger surface area and smaller crystal size.

  2. Fluorescence modulation of cadmium sulfide quantum dots by azobenzene photochromic switches

    PubMed Central

    Javed, Hina; Fatima, Kalsoom; Akhter, Zareen; Nadeem, Muhammad Arif; Siddiq, Muhammad; Iqbal, Azhar

    2016-01-01

    We have investigated the attachment of azobenzene photochromic switches on the modified surface of cadmium sulfide (CdS) quantum dots (QDs). The modification of CdS QDs is done by varying the concentration of the capping agent (mercaptoacetic acid) and NH3 in order to control the size of the QDs. The X-ray diffraction studies revealed that the crystallite size of CdS QDs ranged from 6 to 10 nm. The azobenzene photochromic derivatives bis(4-hydroxybenzene-1-azo)4,4′(1,1′ diphenylmethane) (I) and 4,4′-diazenyldibenzoic acid (II) were synthesized and attached with surface-modified CdS QDs to make fluorophore–photochrome CdS-(I) and CdS-(II) dyad assemblies. Upon UV irradiation, the photochromic compounds (I) and (II) undergo a reversible trans–cis isomerization. The photo-induced trans–cis transformation helps to transfer photo-excited electrons from the conduction band of the CdS QDs to the lowest unoccupied molecular orbital of cis isomer of photochromic compounds (I) and (II). As a result, the fluorescence of CdS-(I) and CdS-(II) dyads is suppressed approximately five times compared to bare CdS QDs. The fluorescence modulation in such systems could help to design luminescent probes for bioimaging applications. PMID:27118894

  3. Surface chemical analysis and electrokinetic properties of synthetic spherical mixed zinc-cadmium sulfides

    SciTech Connect

    Duran, J.D.G.; Guindo, M.C.; Delgado, A.V.; Gonzalez-Caballero, F.

    1997-09-15

    In this work, the authors analyze the surface and bulk chemical composition, as well as the crystal structure, of colloidal spherical particles of Zn-Cd mixed sulfides of different Zn/Cd ratios. Transmission electron microscopy of the particles show that their average diameter ranges from 50--60 nm (when the synthesis is carried out at 50 C) up to 150--200 nm (for a temperature of 70 C). Atomic absorption analysis of the twelve samples obtained indicated that the bulk Zn/Cd ratio increases with aging temperature; the same behavior is found when the concentration of Cd(NO{sub 3}){sub 2} used in the synthesis is decreased. The particles are more oxidized the larger the amount of cadmium on their surface. This is confirmed by electric conductivity determinations in aqueous suspensions of the samples, both in the presence of natural light and in the dark, as a function of time. These data, together with crystal structure determinations by XRD, suggest that, when the growth temperature is 50--60 C, the particles contain a ZnS (sphalerite) nucleus covered by a layer of mixed, hexagonal Zn-CdS and a surface layer of cubic ZnS. When the aging temperature is 70 C, the ZnS core is surrounded by a shell containing cubic ZnS and amorphous CdS. The surface electrical properties of the particles in aqueous suspensions were analyzed by electrophoresis.

  4. Direct electrochemical stripping detection of cystic-fibrosis-related DNA linked through cadmium sulfide quantum dots

    NASA Astrophysics Data System (ADS)

    Marin, Sergio; Merkoçi, Arben

    2009-02-01

    Electrochemical detection of a cadmium sulfide quantum dots (CdS QDs)-DNA complex connected to paramagnetic microbeads (MB) was performed without the need for chemical dissolving. The method is based on dropping 20 µl of CdS QD-DNA-MB suspension on the surface of a screen-printed electrode. It is followed by magnetic collection on the surface of the working electrode and electrochemical detection using square-wave voltammetry (SWV), giving a well-shaped and sensitive analytical signal. A cystic-fibrosis-related DNA sequence was sandwiched between the two DNA probes. One DNA probe is linked via biotin-streptavidin bonding with MB and the other one via thiol groups with the CdS QD used as tags. Nonspecific signals of DNA were minimized using a blocking agent and the results obtained were successfully employed in a model DNA sensor with an interest in future applications in the clinical field. The developed nanoparticle biosensing system may offer numerous opportunities in other fields where fast, low cost and efficient detection of small volume samples is required.

  5. Detection of real sample DNA at a cadmium sulfide--chitosan/gelatin modified electrode.

    PubMed

    Li, Ying; Chen, Wan-Chun; Chen, Shen-Ming; Lou, Bih-Show; Ali, M Ajmal; Al-Hemaid, Fahad M A

    2014-01-01

    Cadmium sulfide (CdS) was combined with chitosan (Chi) and gelatin (Gel) to prepare a CdS-Chi/Gel modified electrode. Chi exhibits a large positive charge density and was to provide a uniform of CdS surface. Gel exhibits high mechanical strength and low toxicity toward mammalian cells, and is non-antigenic biopolymer. CdS-Chi exhibits a lower contact angle than that of bare CdS, indicating that the hydrophilicity of the sample surface had increased. Electrochemical impedance spectroscopy (EIS) was used to determine diffusion coefficients and to characterize the electron transfer kinetics during the redox reactions. The surface morphologies of CdS-Chi and Gel were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Differential pulse voltammetry (DPV) was used to detect the analytes. DPV not only increased the linear range of the electrocatalytic current, but also lowered the overpotential for oxidation interference in the measurements. The CdS electrode exhibited a enhanced electrocatalytic activity toward the analytes evaluated in this study. The presence of Gel enhanced the loading and stability of the electrode. The fabricated electrode was successfully used for the simultaneous electrochemical oxidation of guanine (G) and adenine (A). Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Hydrogen sulfide and proline cooperate to alleviate cadmium stress in foxtail millet seedlings.

    PubMed

    Tian, Baohua; Qiao, Zengjie; Zhang, Liping; Li, Hua; Pei, Yanxi

    2016-12-01

    Hydrogen sulfide (H2S) and some functional amino acids in crops have been involved in the defense system against heavy-metal pollution. Here we report the relationships and functions of H2S and proline to cadmium (Cd) stress. Sodium hydrosulfide (NaHS) pretreatment decreased the electrolytic leakage and the malondialdehyde and hydrogen peroxide contents while enhancing photosynthesis in Cd-treated seedlings. Furthermore, pretreatment with NaHS markedly exacerbated Cd-induced alterations in proline content, the activities of proline-5-carboxylate reductase (P5CR) and proline dehydrogenase (PDH), and the transcript levels of P5CR and PDH. When endogenous H2S was scavenged or inhibited by various H2S modulators, the Cd-induced increase in endogenous proline was weakened. Combined pretreatment with H2S and proline was moderately higher in the Cd-stressed growth status, stomata movements and oxidative damage of seedlings compared to a single treatment with H2S or proline. These results suggest that H2S and proline cooperate to alleviate Cd-damage in foxtail millet.

  7. Design considerations for II-VI multi-gate transistors: the case of cadmium sulfide

    NASA Astrophysics Data System (ADS)

    Conde, J.; Mejia, I.; Aguirre-Tostado, F. S.; Young, C.; Quevedo-Lopez, M. A.

    2014-04-01

    In this paper, we report a feasibility study of MuGFETs (multi-gate field effect transistors) devices using solution-based cadmium sulfide films as the semiconductor. The simulations were carried out using the commercially available ATLAS simulator. Experimental parameters for CdS were extracted from planar thin film transistors fabricated using photolithography methods. Several critical design parameters for MuGFETs devices were studied, including fin width, fin high, channel length, and CdS carrier concentration. Short-channel effects can be reasonably controlled by reducing either fin height or width. It is shown that is possible to fabricate devices that operate in depletion or enhancement mode by controlling the device structure. ION/IOFF ratio was in the range 108-1010, subthreshold slope was closely related to the geometry of the MuGFET. We also observed that as the CdS carrier concentration decreases, the on-voltage shifts to positive values. Optimized MuGFETs simulated in enhancement mode show excellent subthreshold slope, and ION/IOFF ratio ˜1010. This study demonstrates that CdS can be used to fabricate enhanced mode/depletion mode devices using solution-based semiconductors. Furthermore, all processing is kept at temperatures below 100 °C, which demonstrates that these devices can be used in flexible substrates.

  8. An amperometric chloramphenicol immunosensor based on cadmium sulfide nanoparticles modified-dendrimer bonded conducting polymer.

    PubMed

    Kim, Dong-Min; Rahman, Md Aminur; Do, Minh Hien; Ban, Changill; Shim, Yoon-Bo

    2010-03-15

    An amperometric chloramphenicol (CAP) immunosensor was fabricated by covalently immobilizing anti-chloramphenicol acetyl transferase (anti-CAT) antibody on cadmium sulfide nanoparticles (CdS) modified-dendrimer that was bonded to the conducting polymer (poly 5, 2': 5', 2''-terthiophene-3'-carboxyl acid (poly-TTCA)) layer. The AuNPs, dendrimers, and CdS nanoparticles were deposited onto the polymer layer in order to enhance the sensitivity of the sensor probes. The particle sizes were determined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The immobilization of dendrimers, CdS, and anti-CAT were confirmed using energy disruptive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and quartz crystal microbalance (QCM) techniques. The detection of CAP was based on the competitive immuno-interaction between the free- and labeled-CAP for active sites of the anti-CAT. Hydrazine was used as the label for CAP, and it electrochemically catalyzed the reduction of H(2)O(2) at -0.35 V vs. Ag/AgCl. Under optimized conditions, the proposed immunosensor exhibited a linear range of CAP detection between 50 pg/mL and 950 pg/mL, and the detection limit was 45 pg/mL. The immunosensor was examined in real meat samples for the analysis of CAP.

  9. Synthesis, structural and optical properties of Sm{sup 3+} and Nd{sup 3+} doped cadmium sulfide nanocrystals

    SciTech Connect

    L, Saravanan; R, Jayavel; A, Pandurangan; Jih-Hsin, Liu; Hsin-Yuan, Miao

    2014-04-01

    Graphical abstract: Samarium (Sm{sup 3+}) and neodymium (Nd{sup 3+}) doped cadmium sulfide nanocrystals have been prepared via precipitation method. The structural and the luminescent properties of the as-synthesised nanocrystals have been discussed. - Highlights: • Cubic phase lanthanide ion doped cadmium sulfide nanocrystals were prepared by co-precipitation method. • HRTEM displays randomly aggregated nanoparticles with well-defined lattice fringes. • Energy gap and optical properties were affected by the different doping ions. • Effect of Sm and Nd ion doping on photo-emission of CdS nanocrystals was clarified. - Abstract: Cubic phase samarium (Sm{sup 3+}) and neodymium (Nd{sup 3+}) doped cadmium sulfide nanocrystals were synthesized through the chemical co-precipitation method. The crystallite size computed with high intense (1 1 1) peak using Scherrer formula was ∼3 nm. Morphology was examined with scanning electron microscopy (SEM). The transmission electron microscopy (TEM) images further established the formation of nanoclusters and EDAX spectra confirms the presence of cadmium, sulphide and rare earth elements in the sample. SAED pattern shows the crystallinity of the synthesized sample. Blue shift in the bandgap energy in the reflectance UV spectra, illustrates size quantization effect and dopant ion incorporation into the host lattice. The effect of doping concentrations of Sm{sup 3+} and Nd{sup 3+} on the luminescence spectra of CdS was studied. The emission spectra revealed that the intensity increased considerably in the presence of dopant ions. The variation in the optical properties and the enhancement in the luminescence were discussed for different doping levels.

  10. Polycrystalline thin film cadmium telluride solar cells fabricated by electrodeposition

    NASA Astrophysics Data System (ADS)

    Trefny, J. U.; Furtak, T. E.; Williamson, D. L.; Kim, D.

    1994-07-01

    This report describes the principal results of work performed during the second year of a 3-year program at the Colorado School of Mines (CSM). The work on transparent conducting oxides was carried out primarily by CSM students at NREL and is described in three publications listed in Appendix C. The high-quality ZnO produced from the work was incorporated into a copper indium diselenide cell that exhibited a world-record efficiency of 16.4%. Much of the time was devoted to the improvement of cadmium sulfide films deposited by chemical bath deposition methods and annealed with or without a cadmium chloride treatment. Progress was also made in the electrochemical deposition of cadmium telluride. High-quality films yielding CdS/CdTe/Au cells of greater than 10% efficiency are now being produced on a regular basis. We explored the use of zinc telluride back contacts to form an n-i-p cell structure as previously used by Ametek. We began small-angle x-ray scattering (SAXS) studies to characterize crystal structures, residual stresses, and microstructures of both CdTe and CdS. Large SAXS signals were observed in CdS, most likely because of scattering from gain boundaries. The signals observed to date from CdTe are much weaker, indicating a more homogeneous microstructure. We began to use the ADEPT modeling program, developed at Purdue University, to guide our understanding of the CdS/CdTe cell physics and the improvements that will most likely lead to significantly enhanced efficiencies.

  11. Alloys in cadmium telluride solar cells

    NASA Astrophysics Data System (ADS)

    Jensen, Douglas Garth

    Alloys formed intentionally or unintentionally during the fabrication of CdTe/CdS solar cells were investigated. The primary focuses were (1) characterizing thin films of CdTesb{1-x}Ssb{x} since these alloys appear to be present in all high-efficiency CdTe/CdS solar cells, and (2) investigating how these alloys affect solar cell performance. Thin films of CdTesb{1-x}Ssb{x} were fabricated and subjected to heat treatments under conditions identical to those used for making CdTe/CdS solar cells. The films were characterized by X-Ray Diffraction, Energy Dispersive Spectroscopy, Scanning Electron Microscopy, and optical measurements. The as-deposited CdTesb{1-x}Ssb{x} films were generally single-phase even when x was well within the miscibility gap shown on CdTe-CdS pseudo-binary phase diagrams. Heat treatments at 415sp°C in the presence of CdClsb2 promoted phase segregation. From diffraction analysis of the phase-segregated films, the solubility limits at 415sp°C of CdS in CdTe, and of CdTe in CdS were found to be 5.8± 0.2% and 3± 1%, respectively. Conventional CdTe/CdS solar cells and novel solar cells made by depositing CdTesb{1-x}Ssb{x}, in place of CdTe were fabricated, tested, characterized, and compared. For the conventional solar cells, diffusion of CdS into the CdTe layer during the fabrication process converted the CdTe to CdTesb{1-x}Ssb{x} with x ranging from the 5.8% solubility limit near the junction to {<}1% near the back contact. Similarly, the CdS layer was converted to CdSsb{1-y}Tesb{y} with y near the 3% solubility limit, in some cases, and {<}1% in cases where the CdS film was annealed with CdClsb2 prior to depositing CdTe. The performance of CdTesb{1-x}Ssb{x}/CdS cells made with x = 0.05-0.06 throughout the absorber layer was nearly identical to the CdTe/CdS cells. This indicates that the operation of conventional devices is largely controlled by the alloys formed by interdiffusion. For the CdTesb{1-x}Ssb{x}/CdS devices, less CdS was consumed by

  12. Electrodeposited cobalt sulfide hole collecting layer for polymer solar cells

    SciTech Connect

    Zampetti, Andrea; De Rossi, Francesca; Brunetti, Francesca; Reale, Andrea; Di Carlo, Aldo; Brown, Thomas M.

    2014-08-11

    In polymer solar cells based on the blend of regioregular poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester, the hole collecting layer has to be endowed with its ionization potential close to or greater than that of P3HT (∼5 eV). Conductive polymer blends such as poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and metal oxides such as vanadium pentoxide (V{sub 2}O{sub 5}) and molybdenum trioxide (MoO{sub 3}) satisfy this requirement and have been the most common materials used so far in bulk heterojunction structures. We report here cobalt sulfide (CoS) to be a promising hole collecting material deposited by convenient and room temperature electrodeposition. By simply tuning the CoS electrodeposition parameters, power conversion efficiencies similar (within 15%) to a reference structure with PEDOT:PSS were obtained.

  13. Photocurrent spectroscopy of cadmium sulfide/plastic, cadmium sulfide/glass, and zinc telluride/gallium arsenide hetero-pairs formed with pulsed-laser deposition

    NASA Astrophysics Data System (ADS)

    Acharya, Krishna Prasad

    This dissertation presents photocurrent (PC) spectroscopy of thin-film cadmium sulfide (CdS) on plastic, CdS on glass, and zinc telluride (ZnTe) on gallium arsenide (GaAs) hetero-pairs. All samples have been prepared with pulsed-laser deposition (PLD) and the thesis is organized into three principal sections. The first section presents the PLD essentials and characterization of CdS thin films on transparent plastic substrates. The second part focuses on the exploitation of CdS films on glass to quench or modulate alternating photocurrent (APC) by additional constant blue light illumination. Finally, PC spectra modification of n-GaAs due to ZnTe PLD will be investigated. First, the merger of a transparent plastic substrate with thin-film CdS for photonic application was realized using low-temperature PLD, where low-temperature PLD means the substrates were not externally heated. Although plastic is not considered to be a favored substrate material for semiconductor thin-film formation, the deposited CdS film possessed good adhesion to the plastic substrates and showed a blue-shifted photosensitivity with peak at 2.54 eV. The CdS deposition rate was monitored at different laser fluences and the maximum rate was found at 2.68 J/cm2. The visualization of the surface using an atomic force microscope (AFM) revealed its mosaic structure and electron probe microanalysis showed that target composition was maintained in the film. The study of thickness distribution revealed that the film deposition area is significantly increased with increase in laser fluence. The achieved results demonstrate the capability of PLD to form novel heterostructures with appealing and useful technological properties such as plasticity and low weight. In the second part, APC control via blue light illumination employing thin-film PLD CdS on a glass is introduced. In fact, the APC driven through the CdS film in conjunction with bias was quenched when the sample was additionally illuminated with a

  14. Hydrogen sulfide alleviates cadmium-induced morpho-physiological and ultrastructural changes in Brassica napus.

    PubMed

    Ali, Basharat; Gill, Rafaqat A; Yang, Su; Gill, Muhammad B; Ali, Shafaqat; Rafiq, Muhammad T; Zhou, Weijun

    2014-12-01

    In the present study, role of hydrogen sulfide (H2S) in alleviating cadmium (Cd) induced stress in oilseed rape (Brassica napus L.) was studied under greenhouse conditions. Plants were grown hydroponically under three levels (0, 100, and 500µM) of Cd and three levels (0, 100 and 200µM) of H2S donor, sodium hydrosulfide (NaHS). Results showed that application of H2S significantly improved the plant growth, root morphology, chlorophyll contents, elements uptake and photosynthetic activity in B. napus plants under Cd stress. Moreover, addition of H2S reduced the Cd concentration in the leaves and roots of B. napus plants under Cd-toxicity. Exogenously applied H2S decreased the production of malondialdehyde and reactive oxygen species in the leaves and roots by improving the enzymatic antioxidant activities under Cd stress conditions. The microscopic examination indicated that application of exogenous H2S improved the cell structures and enabled a clean mesophyll cell having a well developed chloroplast with thylakoid membranes, and a number of mitochondria could be observed in the micrographs. A number of modifications could be found in root tip cell i.e. mature mitochondria, long endoplasmic reticulum and golgibodies under combined application of H2S and Cd. On the basis of these findings, it can be concluded that application of exogenous H2S has a protective role on plant growth, photosynthetic parameters, elements uptake, antioxidants enzyme activities and ultrastructural changes in B. napus under high Cd stress conditions. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Effects of different annealing atmospheres on the properties of cadmium sulfide thin films

    SciTech Connect

    Yücel, E.; Kahraman, S.; Güder, H.S.

    2015-08-15

    Graphical abstract: The effects of different annealing atmospheres (air and sulfur) on the structural, morphological and optical properties of CdS thin films were studied at three different pH values. - Highlights: • Compactness and smoothness of the films were enhanced after sulfur annealing. • Micro-strain values of some films were improved after sulfur annealing. • Dislocation density values of some films were improved after sulfur annealing. • Band gap values of the films were improved after sulfur annealing. - Abstract: Cadmium sulfide (CdS) thin films were prepared on glass substrates by using chemical bath deposition (CBD) technique. The effects of different annealing atmospheres (air and sulfur) on the structural, morphological and optical properties of CdS thin films were studied at three different pH values. Compactness and smoothness of the films (especially for pH 10.5 and 11) enhanced after sulfur annealing. pH value of the precursor solution remarkably affected the roughness, uniformity and particle sizes of the films. Based on the analysis of X-ray diffraction (XRD) patterns of the films, micro-strain and dislocation density values of the sulfur-annealed films (pH 10.5 and 11) were found to be lower than those of air-annealed films. Air-annealed films (pH 10.5, 11 and 11.5) exhibited higher transmittance than sulfur-annealed films in the wavelength region of 550–800 nm. Optical band gap values of the films were found between 2.31 eV and 2.36 eV.

  16. Cadmium sulfide quantum dots stabilized by castor oil and ricinoleic acid

    NASA Astrophysics Data System (ADS)

    Kyobe, Joseph William; Mubofu, Egid Beatus; Makame, Yahya M. M.; Mlowe, Sixberth; Revaprasadu, Neerish

    2016-02-01

    Castor oil and ricinoleic acid (an isolate of castor oil) are environmentally friendly bio-based organic surfactants that have been used as capping agents to prepare nearly spherical cadmium sulfide quantum dots (QDs) at 230, 250 and 280 °C. The prepared quantum dots were characterized by Ultra violet-visible (UV-vis), Photoluminescence (PL), Transmission Electron Microscopy (TEM), High Resolution Transmission Electron Microscopy (HRTEM) and X-ray diffraction (XRD) giving an overall CdS QDs average size of 5.14±0.39 nm. The broad XRD pattern and crystal lattice fringes in the HRTEM images showed a hexagonal phase composition of the CdS QDs. The calculated/estimated average size of the prepared castor oil capped CdS QDs for various techniques were 4.64 nm (TEM), 4.65 nm (EMA), 5.35 nm (UV-vis) and 6.46 nm (XRD). For ricinoleic acid capped CdS QDs, the average sizes were 5.56 nm (TEM), 4.78 nm (EMA), 5.52 nm (UV-vis) and 8.21 nm (XRD). Optical properties of CdS QDs showed a change of band gap energy from its bulk band gap of 2.42-2.82 eV due to quantum size confinement effect for temperature range of 230-280 °C. Similarly, a blue shift was observed in the photoluminescence spectra. Scanning electron microscope (SEM) observations show that the as-synthesized CdS QDs structures are spherical in shape. Fourier transform infra-red (FTIR) studies confirms the formation of castor oil and ricinoleic acid capped CdS QDs.

  17. Flow-injection chemiluminescence analysis for sensitive determination of atenolol using cadmium sulfide quantum dots.

    PubMed

    Khataee, Alireza; Lotfi, Roya; Hasanzadeh, Aliyeh; Iranifam, Mortaza; Joo, Sang Woo

    2016-03-15

    A sensitive, rapid and simple flow-injection chemiluminescence (CL) system based on the light emitted from KMnO4-cadmium sulfide quantum dots (CdS QDs) reaction in the presence of cetyltrimethylammonium bromide (CTAB) in acidic medium was developed as a CL probe for the sensitive determination of atenolol. Optical and structural features of CdS QDs capped with l-cysteine, which synthesized via hydrothermal approach, were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), and UV-Vis spectroscopy. The CL intensity of KMnO4-CdS QDs-CTAB was remarkably enhanced in the presence of trace level of atenolol. Under optimum experimental conditions, there is a linear relationship between the increase in CL intensity of KMnO4-CdS QDs-CTAB system and atenolol concentration in a range of 0.001 to 4.0 mg L(-1) and 4.0 to 18.0 mg L(-1), with a detection limit (3σ) of 0.0010 mg L(-1). A possible mechanism for KMnO4-CdS QDs-CTAB-atenolol CL reaction is proposed. To prove the practical application of the KMnO4-CdS QDs-CTAB CL method, the method was applied for the determination of atenolol in spiked environmental water samples and commercial pharmaceutical formulation. Furthermore, corona discharge ionization ion mobility spectrometry (CD-IMS) technique was utilized for determination of atenolol. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Towards understanding junction degradation in cadmium telluride solar cells

    SciTech Connect

    Nardone, Marco

    2014-06-21

    A degradation mechanism in cadmium telluride (CdTe/CdS) solar cells is investigated using time-dependent numerical modeling to simulate various temperature, bias, and illumination stress conditions. The physical mechanism is based on defect generation rates that are proportional to nonequilibrium charge carrier concentrations. It is found that a commonly observed degradation mode for CdTe/CdS solar cells can be reproduced only if defects are allowed to form in a narrow region of the absorber layer close to the CdTe/CdS junction. A key aspect of this junction degradation is that both mid-gap donor and shallow acceptor-type defects must be generated simultaneously in response to photo-excitation or applied bias. The numerical approach employed here can be extended to study other mechanisms for any photovoltaic technology.

  19. Cadmium sulfide/copper ternary heterojunction cell research. Final report, April 1, 1980-August 25, 1982

    SciTech Connect

    Mickelsen, R. A.; Chen, W. S.

    1982-08-01

    The properties of polycrystalline, thin-film CuInSe/sub 2//CdS and CuInSe/sub 2//Zn/sub x/Cd/sub 1-x/S solar cells prepared by vacuum-evaporation techniques onto metallized-alumina substrates are described. An efficiency of 10.6% for a 1 cm/sup 2/ area cell and 8.3% for an 8 cm/sup 2/ cell when tested under simulated AM1 illumination is reported. The mixed-sulfide cells are described as exhibiting increased open-circuit voltages, slightly higher short-circuit currents, and improved efficiencies. Mixed-sulfide film preparation by evaporation of CdS and ZnS powders from a single source and from two sources is discussed with preference given to the later technique. Selenide-film preparation in a planetary or rotating substrate vacuum-deposition apparatus is described. A 1 cm/sup 2/ area cell without AR-coating produced by the planetary approach is reported to demonstrate a 7.5% efficiency. The results of cell heat-treatment studies showing a strong environmental dependence are presented and indicate the desirability of an oxygen-containing atmosphere. An automatic, computer-controlled, cell-measurement system for I-V, C-V, and spectral-response analysis is described. The results of the cell-analysis and cell-modeling studies on both the plain CdS and mixed Zn/sub x/Cd/sub 1-x/S thin-film devices are presented. Finally, data obtained from constant illumination and elevated temperature life-tests on the thin-film cells showing little degradation after 9300 hours is reported.

  20. Improving the efficiency of cadmium sulfide-sensitized titanium dioxide/indium tin oxide glass photoelectrodes using silver sulfide as an energy barrier layer and a light absorber.

    PubMed

    Chen, Chong; Zhai, Yong; Li, Chunxi; Li, Fumin

    2014-01-01

    Cadmium sulfide (CdS) and silver sulfide (Ag2S) nanocrystals are deposited on the titanium dioxide (TiO2) nanocrystalline film on indium tin oxide (ITO) substrate to prepare CdS/Ag2S/TiO2/ITO photoelectrodes through a new method known as the molecular precursor decomposition method. The Ag2S is interposed between the TiO2 nanocrystal film and CdS nanocrystals as an energy barrier layer and a light absorber. As a consequence, the energy conversion efficiency of the CdS/Ag2S/TiO2/ITO electrodes is significantly improved. Under AM 1.5 G sunlight irradiation, the maximum efficiency achieved for the CdS(4)/Ag2S/TiO2/ITO electrode is 3.46%, corresponding to an increase of about 150% as compared to the CdS(4)/TiO2/ITO electrode without the Ag2S layer. Our experimental results show that the improved efficiency is mainly due to the formation of Ag2S layer that may increase the light absorbance and reduce the recombination of photogenerated electrons with redox ions from the electrolyte.

  1. Improving the efficiency of cadmium sulfide-sensitized titanium dioxide/indium tin oxide glass photoelectrodes using silver sulfide as an energy barrier layer and a light absorber

    PubMed Central

    2014-01-01

    Cadmium sulfide (CdS) and silver sulfide (Ag2S) nanocrystals are deposited on the titanium dioxide (TiO2) nanocrystalline film on indium tin oxide (ITO) substrate to prepare CdS/Ag2S/TiO2/ITO photoelectrodes through a new method known as the molecular precursor decomposition method. The Ag2S is interposed between the TiO2 nanocrystal film and CdS nanocrystals as an energy barrier layer and a light absorber. As a consequence, the energy conversion efficiency of the CdS/Ag2S/TiO2/ITO electrodes is significantly improved. Under AM 1.5 G sunlight irradiation, the maximum efficiency achieved for the CdS(4)/Ag2S/TiO2/ITO electrode is 3.46%, corresponding to an increase of about 150% as compared to the CdS(4)/TiO2/ITO electrode without the Ag2S layer. Our experimental results show that the improved efficiency is mainly due to the formation of Ag2S layer that may increase the light absorbance and reduce the recombination of photogenerated electrons with redox ions from the electrolyte. PMID:25411566

  2. Improving the efficiency of cadmium sulfide-sensitized titanium dioxide/indium tin oxide glass photoelectrodes using silver sulfide as an energy barrier layer and a light absorber

    NASA Astrophysics Data System (ADS)

    Chen, Chong; Zhai, Yong; Li, Chunxi; Li, Fumin

    2014-11-01

    Cadmium sulfide (CdS) and silver sulfide (Ag2S) nanocrystals are deposited on the titanium dioxide (TiO2) nanocrystalline film on indium tin oxide (ITO) substrate to prepare CdS/Ag2S/TiO2/ITO photoelectrodes through a new method known as the molecular precursor decomposition method. The Ag2S is interposed between the TiO2 nanocrystal film and CdS nanocrystals as an energy barrier layer and a light absorber. As a consequence, the energy conversion efficiency of the CdS/Ag2S/TiO2/ITO electrodes is significantly improved. Under AM 1.5 G sunlight irradiation, the maximum efficiency achieved for the CdS(4)/Ag2S/TiO2/ITO electrode is 3.46%, corresponding to an increase of about 150% as compared to the CdS(4)/TiO2/ITO electrode without the Ag2S layer. Our experimental results show that the improved efficiency is mainly due to the formation of Ag2S layer that may increase the light absorbance and reduce the recombination of photogenerated electrons with redox ions from the electrolyte.

  3. CADMIUM SOLUBILITY IN PADDY SOILS: EFFECTS OF SOIL OXIDATION, METAL SULFIDES AND COMPETITIVE IONS.

    EPA Science Inventory

    Cadmium (Cd) is a non-essential element for human nutrition and is an agricultural soil contaminant. Cadmium solubility in paddy soils affects Cd accumulation in the grain of rice. This is a human health risk, exacerbated by the fact that rice grains are deficient in iron (Fe) an...

  4. CADMIUM SOLUBILITY IN PADDY SOILS: EFFECTS OF SOIL OXIDATION, METAL SULFIDES AND COMPETITIVE IONS.

    EPA Science Inventory

    Cadmium (Cd) is a non-essential element for human nutrition and is an agricultural soil contaminant. Cadmium solubility in paddy soils affects Cd accumulation in the grain of rice. This is a human health risk, exacerbated by the fact that rice grains are deficient in iron (Fe) an...

  5. Solar Photovoltaic Cells.

    ERIC Educational Resources Information Center

    Mickey, Charles D.

    1981-01-01

    Reviews information on solar radiation as an energy source. Discusses these topics: the key photovoltaic material; the bank theory of solids; conductors, semiconductors, and insulators; impurity semiconductors; solid-state photovoltaic cell operation; limitations on solar cell efficiency; silicon solar cells; cadmium sulfide/copper (I) sulfide…

  6. Solar Photovoltaic Cells.

    ERIC Educational Resources Information Center

    Mickey, Charles D.

    1981-01-01

    Reviews information on solar radiation as an energy source. Discusses these topics: the key photovoltaic material; the bank theory of solids; conductors, semiconductors, and insulators; impurity semiconductors; solid-state photovoltaic cell operation; limitations on solar cell efficiency; silicon solar cells; cadmium sulfide/copper (I) sulfide…

  7. Horizon-specific oxidation of acid volatile sulfide (AVS) in relation to the toxicity of cadmium spiked into a freshwater sediment

    SciTech Connect

    Leonard, E.N.; Mattson, V.R.; Ankley, G.T.

    1994-12-31

    To evaluate the effects of oxidative processes on acid volatile sulfide concentrations in various horizons of whole sediment cores, in relation to the toxicity of a metal (cadmium), the authors used an artificial system to ``age`` Cd-spiked sediment samples under a constant flow of fresh Lake Superior water. Sediments from Pequaywan Lake, MN (ca. 12 umol AVS/g) were spiked so as to achieve (nominal) cadmium: AVS molar ratios of 0.02 (control), 0.2, 0.8, 1.2 and 3.0. At 0, 24 and 48 days post-spiking, sediment cores were removed from the aging system and tested for toxicity to the amphipod Hyalella azteca. At the same time, horizons from replicate sediment cores were prepared for analysis by freezing, and then cutting them into 10--20 mm increments. The sediment horizons were analyzed for AVS and simultaneously extracted cadmium concentrations, and pore water concentrations of cadmium. Relatively little oxidation of surficial AVS concentrations was observed, even at aging times up to 48 d. By 48 d, pore water concentrations of cadmium were slightly elevated at all spiking concentrations, but were increased greatly at cadmium:AVS ratios greater than one. Hyalella azteca mortality was generally predictable based on surficial cadmium:AVS ratios or pore water cadmium concentrations.

  8. Flow-injection chemiluminescence analysis for sensitive determination of atenolol using cadmium sulfide quantum dots

    NASA Astrophysics Data System (ADS)

    Khataee, Alireza; Lotfi, Roya; Hasanzadeh, Aliyeh; Iranifam, Mortaza; Joo, Sang Woo

    2016-03-01

    A sensitive, rapid and simple flow-injection chemiluminescence (CL) system based on the light emitted from KMnO4-cadmium sulfide quantum dots (CdS QDs) reaction in the presence of cetyltrimethylammonium bromide (CTAB) in acidic medium was developed as a CL probe for the sensitive determination of atenolol. Optical and structural features of CdS QDs capped with L-cysteine, which synthesized via hydrothermal approach, were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), and UV-Vis spectroscopy. The CL intensity of KMnO4-CdS QDs-CTAB was remarkably enhanced in the presence of trace level of atenolol. Under optimum experimental conditions, there is a linear relationship between the increase in CL intensity of KMnO4-CdS QDs-CTAB system and atenolol concentration in a range of 0.001 to 4.0 mg L- 1 and 4.0 to 18.0 mg L- 1, with a detection limit (3σ) of 0.0010 mg L- 1. A possible mechanism for KMnO4-CdS QDs-CTAB-atenolol CL reaction is proposed. To prove the practical application of the KMnO4-CdS QDs-CTAB CL method, the method was applied for the determination of atenolol in spiked environmental water samples and commercial pharmaceutical formulation. Furthermore, corona discharge ionization ion mobility spectrometry (CD-IMS) technique was utilized for determination of atenolol. Figure S2. Optimization of the CL reaction conditions: (a) effect of KMnO4 concentration. Conditions: the concentrations of H2SO4, CdS QDs and atenolol were 1 mol L-1, 0.35 mol L-1, and 4.0 mg L-1, respectively; (b) effect of acidic media. Conditions: the concentrations of KMnO4 was 0.04 mmol L-1, other conditions were as in (a); (c) effect of CdS QDs concentration. Conditions: H2SO4 concentration was 1.0 mol L-1, other conditions were as in (b), and (d) effect of CTAB concentration. Conditions: CdS QDs concentration was 0.35 mmol L-1, other conditions were as in (c). Figure S3. UV-Vis absorption spectra of KMnO4-CdS QDs-atenolol CL system

  9. Lossless synthesis of graphene nanosheets decorated with tiny cadmium sulfide quantum dots with excellent nonlinear optical properties.

    PubMed

    Feng, Miao; Sun, Ruiqing; Zhan, Hongbing; Chen, Yu

    2010-02-19

    The implantation and growth of metal nanoparticles on graphene nanosheets (GNS) leads directly to severe damage to the regular structure of the graphene sheets, which disrupts the extended pi conjugation, resulting in an impaired device performance. In this paper, we describe a facile approach for achieving the lossless formation of graphene composite decorated with tiny cadmium sulfide quantum dots (QDs) with excellent nonlinear optical properties by using benzyl mercaptan (BM) as the interlinker. The mercapto substituent of BM binds to the CdS QDs during their nucleation and growth process, and then the phenyl comes into contact with the GNS via the pi-pi stacking interaction. Using this strategy, CdS QDs with an average diameter of 3 nm are uniformly dispersed over the surface of graphene, and the resulting QD-graphene composite exhibits excellent optical limiting properties, mainly contributed by nonlinear scattering and nonlinear absorption, upon both 532 and 1064 nm excitations, in the nanosecond laser pulse regime.

  10. The influence of pH and cadmium sulfide on the photocatalytic degradation of 2-chlorophenol in titanium dioxide suspensions.

    PubMed

    Doong, R A; Chen, C H; Maithreepala, R A; Chang, S M

    2001-08-01

    The influence of pH and cadmium sulfide on the photocatalytic degradation of 2-chlorophenol (2-CP) in titanium dioxide suspensions was investigated to evaluate the feasibility of mixed semiconductors on the photodegradation of chlorinated organics in aqueous solution. Apparent first-order rate constants (k(obs)) and initial rate constants were used to evaluate the degradation efficiency of 2-CP. Higher degradation efficiency of 2-CP was observed at higher pH values. The apparent pseudo-first-order rate constant was 0.036 min(-1) at pH 12.5 in TiO2/UV system, while a 2- to 9-fold decrease in k(obs) was observed over the pH range of 2.5-9.5. The addition of phosphate buffer solutions at different pH values have different effects on the degradation of 2-CP. H2PO4- has little effect on the photodegradation of 2-CP, while HPO4(2-) could inhibit the photodegradation efficiency of 2-CP. Chlorocatechol, hydroquinone, benzoquinone and phenol were identified as the predominant aromatic intermediates for the photocatalytic degradation of 2-CP. Moreover, less aromatic intermediates at higher pH were observed. Direct oxidation contributed significantly to the photodegradation of 2-CP. An addition of a semiconductor decreased the initial and apparent first-order rate constants of 2-CP. The cutoff of wavelength of 320nm could diminish the contribution of direct photolysis of 2-CP. The combination of cadmium sulfide and titanium dioxide can lead to an enhanced rate of disappearance of 2-CP compared to those in single semiconductor system. A 1.2 to 2.5-fold increase in rate constant in coupled semiconductor system relative to the single semiconductor system was obtained.

  11. Solar decomposition of cadmium oxide for hydrogen production. Final subcontract report

    SciTech Connect

    Schreiber, J. D.; Yudow, B. D.; Carty, R. H.; Whaley, T. P.; Pangborn, J. B.

    1981-11-01

    The reactor developed for this study performed satisfactorily in establishing the feasibility of cadmium oxide decomposition under the realistic conditions of the solar-furnace environment. The solar-furnace environment is very appropriate for the evaluation of design concepts. However, the solar furnace probably cannot give precise rate data. The flux is too nonuniform, so temperatures of reactant and corresponding reaction rates are also nonuniform. One of the most important results of this project was the recovery of samples from the quench heat exchanger that contained a surprisingly large amount of metallic cadmium. The fact that the sample taken from the quench heat exchanger was metallic in appearance and contained between 67% and 84% metallic cadmium would tend to indicate recombination of cadmium vapor and oxygen can be effectively prevented by the quenching operation. It would also tend to confirm recent studies that show cadmium oxide does not sublime appreciably. Determination of the decomposition rate of cadmium oxide was severely limited by fluctuating and nonuniform reactant temperatures and baseline drift in the oxygen sensor. However, the estimated rate based on a single run seemed to follow a typical solid decomposition rate pattern with an initial acceleratory period, followed by a longer deceleratory period. From a preliminary flowsheet analysis of the cadmium-cadmium oxide cycle, it was determined that at a cadmium oxide decomposition temperature of 1400/sup 0/C and a requirement of 0.2 V in the electrolyzer the efficiency was 41%, assuming total quenching of the cadmium oxide decomposition products. This efficiency could increase to a maximum of 59% if total recovery of the latent heats of vaporization and fusion of the decomposition products is possible.

  12. High temperature solar thermochemical processing - Hydrogen and sulfur from hydrogen sulfide

    NASA Astrophysics Data System (ADS)

    Noring, J. E.; Fletcher, E. A.

    1982-08-01

    Sunlight, concentrated to high intensities, has a rarely recognized potential for adding process heat to reactors at high temperatures. Hydrogen sulfide is a by-product of the sweetening of fossil fuels. In this paper, by way of example, the production of hydrogen and sulfur from hydrogen sulfide is used as a device for showing how solar processing might be considered as a successor to a currently used industrial process, the Claus process. It is concluded that this and other processes should be explored as means of using as well as storing solar energy.

  13. Methodological approach to study energetic and structural properties of nanostructured cadmium sulfide by using ab-initio molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Burresi, E.; Celino, M.

    2012-05-01

    A single wurtzite phase of cadmium sulfide cluster is investigated by ab-initio molecular dynamics simulations at different temperatures, ranging from 100 K to 600 K. In this study we propose a possible procedure to characterize the CdS quantum dots system by means of molecular dynamics calculations using a standard Car-Parrinello scheme. In order to ensure the accuracy of the numerical approach, preliminary calculations to test pseudopotentials, cutoff and box size on both single atoms systems and Cd-Cd, S-S, Cd-S dimers have been performed. Calculated binding energies and bond lengths are obtained in good agreement with experimental data. Subsequently, an uncapped CdS cluster with size below 2 nm, 48 atoms of cadmium and 48 atoms of sulfur, in a wurtzite geometry was structurally optimized to minimize internal stresses. The CdS cluster has been carefully characterized structurally at several temperatures up to T = 600 K. At the temperature of 340 K atomic diffusion on the surface allows the onset of a new stable atomic configuration.

  14. Phytochelatins in Cadmium-Sensitive and Cadmium-Tolerant Silene vulgaris (Chain Length Distribution and Sulfide Incorporation).

    PubMed Central

    De Knecht, J. A.; Van Dillen, M.; Koevoets, PLM.; Schat, H.; Verkleij, JAC.; Ernst, WHO.

    1994-01-01

    In response to a range of Cd concentrations, the root tips of Cd-tolerant plants of Silene vulgaris exhibit a lower rate of PC production accompanied by a lower rate of longer chain PC synthesis than those of Cd-sensitive plants. At the same Cd exposure level, stable PC-Cd complexes are more rapidly formed in the roots of Cd-sensitive plants than in those of tolerant plants. At an equal PC concentration in the roots, the PC composition and the amount of sulfide incorporated per unit of PC-thiol is the same in both populations. Although these compounds might play some role in mechanisms that contribute to Cd detoxification, the ability to produce these compounds in greater amounts is not, itself, the mechanism that produces increased Cd tolerance in tolerant S. vulgaris plants. PMID:12232077

  15. Photocatalytic Activities of Copper Doped Cadmium Sulfide Microspheres Prepared by a Facile Ultrasonic Spray-Pyrolysis Method.

    PubMed

    Su, Jinzhan; Zhang, Tao; Li, Yufeng; Chen, Yubin; Liu, Maochang

    2016-06-15

    Ultrasonic spray pyrolysis is a superior method for preparing and synthesizing spherical particles of metal oxide or sulfide semiconductors. Cadmium sulfide (CdS) photocatalysts with different sizes and doped-CdS with different dopants and doping levels have been synthesized to study their properties of photocatalytic hydrogen production from water. The CdS photocatalysts were characterized with scanning electron microscopy (SEM), X-ray fluorescence-spectrometry (XRF), UV-Vis absorption spectra and X-ray diffraction (XRD) to study their morphological and optical properties. The sizes of the prepared CdS particles were found to be proportional to the concentration of the metal nitrates in the solution. The CdS photocatalyst with smaller size showed a better photocatalytic activity. In addition, Cu doped CdS were also deposited and their photocatalytic activities were also investigated. Decreased bandgaps of CdS synthesized with this method were found and could be due to high density surface defects originated from Cd vacancies. Incorporating the Cu elements increased the bandgap by taking the position of Cd vacancies and reducing the surface defect states. The optimal Cu-doped level was found to be 0.5 mol % toward hydrogen evolution from aqueous media in the presence of sacrificial electron donors (Na₂S and Na₂SO₃) at a pH of 13.2. This study demonstrated that ultrasonic spray pyrolysis is a feasible approach for large-scale photocatalyst synthesis and corresponding doping modification.

  16. Effects of Buffer Salt Concentration on the Dominated Deposition Mechanism and Optical Characteristics of Chemically Deposited Cadmium Sulfide Thin Films

    NASA Astrophysics Data System (ADS)

    Kakhaki, Z. Makhdoumi; Youzbashi, A.; Sangpour, P.; Kazemzadeh, A.; Naderi, N.; Bazargan, A. M.

    2016-02-01

    Effects of buffer salt concentration on the rate of deposition, dominated deposition mechanism and subsequently the structural, morphological, and optical properties of cadmium sulfide (CdS) thin films deposited by chemical bath deposition (CBD) on glass substrate were investigated. The precursors were chosen to be cadmium chloride (CdCl2) as the cadmium source, thiourea (CS(NH2)2) as the sulfur source, ammonium nitrate (NH4NO3) as the buffer salt and ammonia as the complexing agent and the pH controller. The influence of the NH4NO3 concentration on the structure, morphology, film uniformity, stoichiometry and optical properties of CdS thin films was also studied by X-ray diffractometer (XRD), field emission scanning electron microscope (FE-SEM), energy dispersive X-ray (EDX) spectroscope, uv-visible and photoluminescence (PL) spectroscopes. The XRD studies revealed that all the deposited films exhibited a (002)h/(111)c preferred orientation. The crystallite size was increased from 20nm to 30nm by the increase of concentration of NH4NO3 from 0.5M to 2.5M. The morphology of CdS thin films were agglomerated spherical particles consisted of smaller particles. The surface of thin films deposited at the NH4NO3 concentration of 0.5M was compact and smooth. The increase of the concentration of NH4NO3 decreased the packing density of the films. The optical band gap was in the range of 2.25-2.4eV, which was decreased by the decrement of packing density. The PL spectra showed two peaks centered at 400nm and 500nm which are attributed to violet and band-to-band emissions, respectively.

  17. Incorporation of sulfide ions into the cadmium(II) thiolate cluster of Cicer arietinum metallothionein2.

    PubMed

    Wan, Xiaoqiong; Freisinger, Eva

    2013-01-18

    The plant metallothionein2 from Cicer arietinum (chickpea), cic-MT2, is known to coordinate five divalent metal ions such as Zn(II) or Cd(II), which are arranged in a single metal thiolate cluster. When the Zn(II) form of the protein is titrated with Cd(II) ions in the presence of sulfide ions, an increased Cd(II) binding capacity and concomitant incorporation of sulfide ions into the cluster are observed. The exact stoichiometry of this novel cluster, its spectroscopic properties, and the significantly increased pH stability are analyzed with different techniques, including UV and circular dichroism spectroscopy and colorimetric assays. Limited proteolytic digestion provides information about the spacial arrangement of the cluster within the protein. Increasing the Cd(II) scavenging properties of a metallothionein by additionally recruiting sulfide ions might be an economic and very efficient detoxification strategy for plants.

  18. Study of upscaling possibilities for antimony sulfide solid state sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Nikolakopoulou, Archontoula; Raptis, Dimitrios; Dracopoulos, Vasilios; Sygellou, Lamprini; Andrikopoulos, Konstantinos S.; Lianos, Panagiotis

    2015-03-01

    Solid state solar cells of inverted structure were constructed by successive deposition of nanoparticulate titania, antimony sulfide sensitizer and P3HT on FTO electrodes with PEDOT:PSS:Ag as counter electrode. Sensitized photoanode electrodes were characterized by XRD, Raman, XPS, FESEM and UV-vis. Small laboratory scale cells were first constructed and optimized. Functional cells were obtained by annealing the antimony sulfide film either in air or in inert atmosphere. High short-circuit currents were recorded in both cases with air-annealed sample producing more current but lower voltage. Small unit cells were combined to form cell modules. Connection of unit cells in parallel increased current but not proportionally to that of the unit cell. Connection in series preserved current and generated voltage multiplication. Cells were constructed and studied under ambient conditions, without encapsulation. The results encourage upscaling of antimony sulfide solar cells.

  19. Integration of Semiconducting Sulfides for Full-Spectrum Solar Energy Absorption and Efficient Charge Separation.

    PubMed

    Zhuang, Tao-Tao; Liu, Yan; Li, Yi; Zhao, Yuan; Wu, Liang; Jiang, Jun; Yu, Shu-Hong

    2016-05-23

    The full harvest of solar energy by semiconductors requires a material that simultaneously absorbs across the whole solar spectrum and collects photogenerated electrons and holes separately. The stepwise integration of three semiconducting sulfides, namely ZnS, CdS, and Cu2-x S, into a single nanocrystal, led to a unique ternary multi-node sheath ZnS-CdS-Cu2-x S heteronanorod for full-spectrum solar energy absorption. Localized surface plasmon resonance (LSPR) in the nonstoichiometric copper sulfide nanostructures enables effective NIR absorption. More significantly, the construction of pn heterojunctions between Cu2-x S and CdS leads to staggered gaps, as confirmed by first-principles simulations. This band alignment causes effective electron-hole separation in the ternary system and hence enables efficient solar energy conversion. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Cadmium-Induced Hydrogen Sulfide Synthesis Is Involved in Cadmium Tolerance in Medicago sativa by Reestablishment of Reduced (Homo)glutathione and Reactive Oxygen Species Homeostases

    PubMed Central

    Cui, Weiti; Chen, Huiping; Zhu, Kaikai; Jin, Qijiang; Xie, Yanjie; Cui, Jin; Xia, Yan; Zhang, Jing; Shen, Wenbiao

    2014-01-01

    Until now, physiological mechanisms and downstream targets responsible for the cadmium (Cd) tolerance mediated by endogenous hydrogen sulfide (H2S) have been elusive. To address this gap, a combination of pharmacological, histochemical, biochemical and molecular approaches was applied. The perturbation of reduced (homo)glutathione homeostasis and increased H2S production as well as the activation of two H2S-synthetic enzymes activities, including L-cysteine desulfhydrase (LCD) and D-cysteine desulfhydrase (DCD), in alfalfa seedling roots were early responses to the exposure of Cd. The application of H2S donor sodium hydrosulfide (NaHS), not only mimicked intracellular H2S production triggered by Cd, but also alleviated Cd toxicity in a H2S-dependent fashion. By contrast, the inhibition of H2S production caused by the application of its synthetic inhibitor blocked NaHS-induced Cd tolerance, and destroyed reduced (homo)glutathione and reactive oxygen species (ROS) homeostases. Above mentioned inhibitory responses were further rescued by exogenously applied glutathione (GSH). Meanwhile, NaHS responses were sensitive to a (homo)glutathione synthetic inhibitor, but reversed by the cotreatment with GSH. The possible involvement of cyclic AMP (cAMP) signaling in NaHS responses was also suggested. In summary, LCD/DCD-mediated H2S might be an important signaling molecule in the enhancement of Cd toxicity in alfalfa seedlings mainly by governing reduced (homo)glutathione and ROS homeostases. PMID:25275379

  1. Cadmium-induced hydrogen sulfide synthesis is involved in cadmium tolerance in Medicago sativa by reestablishment of reduced (homo)glutathione and reactive oxygen species homeostases.

    PubMed

    Cui, Weiti; Chen, Huiping; Zhu, Kaikai; Jin, Qijiang; Xie, Yanjie; Cui, Jin; Xia, Yan; Zhang, Jing; Shen, Wenbiao

    2014-01-01

    Until now, physiological mechanisms and downstream targets responsible for the cadmium (Cd) tolerance mediated by endogenous hydrogen sulfide (H2S) have been elusive. To address this gap, a combination of pharmacological, histochemical, biochemical and molecular approaches was applied. The perturbation of reduced (homo)glutathione homeostasis and increased H2S production as well as the activation of two H2S-synthetic enzymes activities, including L-cysteine desulfhydrase (LCD) and D-cysteine desulfhydrase (DCD), in alfalfa seedling roots were early responses to the exposure of Cd. The application of H2S donor sodium hydrosulfide (NaHS), not only mimicked intracellular H2S production triggered by Cd, but also alleviated Cd toxicity in a H2S-dependent fashion. By contrast, the inhibition of H2S production caused by the application of its synthetic inhibitor blocked NaHS-induced Cd tolerance, and destroyed reduced (homo)glutathione and reactive oxygen species (ROS) homeostases. Above mentioned inhibitory responses were further rescued by exogenously applied glutathione (GSH). Meanwhile, NaHS responses were sensitive to a (homo)glutathione synthetic inhibitor, but reversed by the cotreatment with GSH. The possible involvement of cyclic AMP (cAMP) signaling in NaHS responses was also suggested. In summary, LCD/DCD-mediated H2S might be an important signaling molecule in the enhancement of Cd toxicity in alfalfa seedlings mainly by governing reduced (homo)glutathione and ROS homeostases.

  2. Hydrogen sulfide - cysteine cycle system enhances cadmium tolerance through alleviating cadmium-induced oxidative stress and ion toxicity in Arabidopsis roots

    PubMed Central

    Jia, Honglei; Wang, Xiaofeng; Dou, Yanhua; Liu, Dan; Si, Wantong; Fang, Hao; Zhao, Chen; Chen, Shaolin; Xi, Jiejun; Li, Jisheng

    2016-01-01

    Cadmium (Cd2+) is a common toxic heavy metal ion. We investigated the roles of hydrogen sulfide (H2S) and cysteine (Cys) in plant responses to Cd2+ stress. The expression of H2S synthetic genes LCD and DES1 were induced by Cd2+ within 3 h, and endogenous H2S was then rapidly released. H2S promoted the expression of Cys synthesis-related genes SAT1 and OASA1, which led to endogenous Cys accumulation. The H2S and Cys cycle system was stimulated by Cd2+ stress, and it maintained high levels in plant cells. H2S inhibited the ROS burst by inducing alternative respiration capacity (AP) and antioxidase activity. H2S weakened Cd2+ toxicity by inducing the metallothionein (MTs) genes expression. Cys promoted GSH accumulation and inhibited the ROS burst, and GSH induced the expression of phytochelatin (PCs) genes, counteracting Cd2+ toxicity. In summary, the H2S and Cys cycle system played a key role in plant responses to Cd2+ stress. The Cd2+ tolerance was weakened when the cycle system was blocked in lcddes1-1 and oasa1 mutants. This paper is the first to describe the role of the H2S and Cys cycle system in Cd2+ stress and to explore the relevant and specificity mechanisms of H2S and Cys in mediating Cd2+ stress. PMID:28004782

  3. Size-controlled one-pot synthesis of fluorescent cadmium sulfide semiconductor nanoparticles in an apoferritin cavity

    NASA Astrophysics Data System (ADS)

    Iwahori, K.; Yamashita, I.

    2008-12-01

    A simple size-controlled synthesis of cadmium sulfide (CdS) nanoparticle (NP) cores in the cavity of apoferritin from horse spleen (HsAFr) was performed by a slow chemical reaction synthesis and a two-step synthesis protocol. We found that the CdS NP core synthesis was slow and that premature CdS NP cores were formed in the apoferritin cavity when the concentration of ammonia water was low. It was proven that the control of the ammonia water concentration can govern the CdS NP core synthesis and successfully produce size-controlled CdS NP cores with diameters from 4.7 to 7.1 nm with narrow size dispersion. X-ray powder diffraction (XRD), energy dispersive spectroscopy (EDS) analysis and high-resolution transmission electron microscopy (HR-TEM) observation characterized the CdS NP cores obtained as cubic polycrystalline NPs, which showed photoluminescence with red shifts depending on their diameters. From the research of CdS NP core synthesis in the recombinant apoferritins, the zeta potential of apoferritin is important for the biomineralization of CdS NP cores in the apoferritin cavity. These synthesized CdS NPs with different photoluminescence properties will be applicable in a wide variety of nano-applications.

  4. A highly stable electrochemiluminescence sensing system of cadmium sulfide nanowires/graphene hybrid for supersensitive detection of pentachlorophenol

    NASA Astrophysics Data System (ADS)

    Deng, Yanan; Chang, Quanying; Yin, Kai; Liu, Chengbin; Wang, Ying

    2017-10-01

    A highly stable and effective electrochemiluminescence (ECL) sensing system of cadmium sulfide nanowires/reduced graphene oxide (CdS NWS/rGO) hybrid is presented for supersensitive detection of pentachlorophenol (PCP). CdS nanowire is for the first time exploited in ECL sensing. The rGO served as both ECL signal amplifier and immobilization platform, can perfectly enhance the ECL intensity and stability of the sensing system. With S2O82- as coreactant, the ECL signal can be significantly quenched by the addition of PCP. The established ECL sensing system presents a wider linear range from 1.0 × 10-14 to 1.0 × 10-8 M and a much low detection limit of 2 × 10-15 M under the optimum test conditions (e.g., pH 7.0 and 100 mM S2O82-). Furthermore, the ECL sensing system displays a good selectivity for PCP detection. The practicability of the ECL sensing system in real water sample shows that this system could be promisingly applied in the analytical detection of PCP in real water environments.

  5. A circular dichroism sensor for Ni(2+) and Co(2+) based on L-cysteine capped cadmium sulfide quantum dots.

    PubMed

    Tedsana, Wimonsiri; Tuntulani, Thawatchai; Ngeontae, Wittaya

    2015-03-31

    A new circular dichroism sensor for detecting Ni(2+) and Co(2+) was proposed for the first time using chiral chelating quantum dots. The detection principle was based on changing of circular dichroism signals of the chiral quantum dots when forming a chiral complex with Ni(2+) or Co(2+). L-Cysteine capped cadmium sulfide quantum dots (L-Cyst-CdS QDs) were proposed as a chiral probe. The CD spectrum of L-Cyst-CdS QDs was significantly changed in the presence of Ni(2+) and Co(2+). On the other hand, other studied cations did not alter the original CD spectrum. Moreover, when increasing the concentration of Ni(2+) or Co(2+), the intensity of the CD spectrum linearly increased as a function of concentration and could be useful for the quantitative analysis. The proposed CD sensor showed linear working concentration ranges of 10-60 μM and 4-80 μM with low detection limits of 7.33 μМ and 1.13 μM for the detection of Ni(2+) and Co(2+), respectively. Parameters possibly affected the detection sensitivity such as solution pH and incubation time were studied and optimized. The proposed sensor was applied to detect Ni(2+) and Co(2+) in real water samples, and the results agreed well with the analysis using the standard ICP-OES. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Facile covalent immobilization of cadmium sulfide quantum dots on graphene oxide nanosheets: preparation, characterization, and optical properties

    NASA Astrophysics Data System (ADS)

    Pham, Tuan Anh; Choi, Byung Choon; Jeong, Yeon Tae

    2010-11-01

    A facile approach for the preparation of a novel hybrid material containing graphene and an inorganic semiconducting material, cadmium sulfide quantum dots (CdS QDs), is demonstrated for the first time. First, amino-functionalized CdS QDs were prepared by modifications of the kinetic trapping method. Then, pristine graphite was oxidized and exfoliated to obtain graphene oxide nanosheets (GONS), which were then acylated with thionyl chloride to introduce acyl chloride groups on their surface. Subsequently, immobilization of the CdS QDs on the GONS surface was achieved through an amidation reaction between the amino groups located on the CdS QDs surface and the acyl chloride groups bound to the GONS surface. Fourier transform infrared spectroscopy (FT-IR), 1H nuclear magnetic resonance (1H-NMR), x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and energy dispersive x-ray (EDX) spectroscopy were employed to investigate the changes in the surface functionalities, while high resolution transmission electron microscopy (HR-TEM) and field emission scanning electronic microscopy (FE-SEM) were used to study the morphologies and distribution of the CdS QDs on the GONS surface. Thermogravimetric analysis (TGA) was employed to characterize the weight loss of the samples on heating. Photoluminescence (PL) measurements were used to study the optical properties of the prepared CdS QDs and the CdS-graphene hybrid material.

  7. Facile covalent immobilization of cadmium sulfide quantum dots on graphene oxide nanosheets: preparation, characterization, and optical properties.

    PubMed

    Pham, Tuan Anh; Choi, Byung Choon; Jeong, Yeon Tae

    2010-11-19

    A facile approach for the preparation of a novel hybrid material containing graphene and an inorganic semiconducting material, cadmium sulfide quantum dots (CdS QDs), is demonstrated for the first time. First, amino-functionalized CdS QDs were prepared by modifications of the kinetic trapping method. Then, pristine graphite was oxidized and exfoliated to obtain graphene oxide nanosheets (GONS), which were then acylated with thionyl chloride to introduce acyl chloride groups on their surface. Subsequently, immobilization of the CdS QDs on the GONS surface was achieved through an amidation reaction between the amino groups located on the CdS QDs surface and the acyl chloride groups bound to the GONS surface. Fourier transform infrared spectroscopy (FT-IR), (1)H nuclear magnetic resonance ((1)H-NMR), x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and energy dispersive x-ray (EDX) spectroscopy were employed to investigate the changes in the surface functionalities, while high resolution transmission electron microscopy (HR-TEM) and field emission scanning electronic microscopy (FE-SEM) were used to study the morphologies and distribution of the CdS QDs on the GONS surface. Thermogravimetric analysis (TGA) was employed to characterize the weight loss of the samples on heating. Photoluminescence (PL) measurements were used to study the optical properties of the prepared CdS QDs and the CdS-graphene hybrid material.

  8. Hydrogen Sulfide Alleviates Cadmium-Induced Cell Death through Restraining ROS Accumulation in Roots of Brassica rapa L. ssp. pekinensis

    PubMed Central

    2015-01-01

    Hydrogen sulfide (H2S) is a cell signal molecule produced endogenously and involved in regulation of tolerance to biotic and abiotic stress in plants. In this work, we used molecular biology, physiology, and histochemical methods to investigate the effects of H2S on cadmium- (Cd-) induced cell death in Chinese cabbage roots. Cd stress stimulated a rapid increase of endogenous H2S in roots. Additionally, root length was closely related to the cell death rate. Pretreatment with sodium hydrosulfide (NaHS), a H2S donor, alleviated the growth inhibition caused by Cd in roots—this effect was more pronounced at 5 μM NaHS. Cd-induced cell death in roots was significantly reduced by 5 μM NaHS treatment. Under Cd stress, activities of the antioxidant enzymes were significantly enhanced in roots. NaHS + Cd treatment made their activities increase further compared with Cd exposure alone. Enhanced antioxidant enzyme activity led to a decline in reactive oxygen species accumulation and lipid peroxidation. In contrast, these effects were reversed by hydroxylamine, a H2S inhibitor. These results suggested that H2S alleviated the cell death caused by Cd via upregulation of antioxidant enzyme activities to remove excessive reactive oxygen species and reduce cell oxidative damage. PMID:26078819

  9. The Proteomic Response of Arabidopsis thaliana to Cadmium Sulfide Quantum Dots, and Its Correlation with the Transcriptomic Response

    PubMed Central

    Marmiroli, Marta; Imperiale, Davide; Pagano, Luca; Villani, Marco; Zappettini, Andrea; Marmiroli, Nelson

    2015-01-01

    A fuller understanding of the interaction between plants and engineered nanomaterials is of topical relevance because the latter are beginning to find applications in agriculture and the food industry. There is a growing need to establish objective safety criteria for their use. The recognition of two independent Arabidopsis thaliana mutants displaying a greater level of tolerance than the wild type plant to exposure to cadmium sulfide quantum dots (CdS QDs) has offered the opportunity to characterize the tolerance response at the physiological, transcriptomic, and proteomic levels. Here, a proteomics-based comparison confirmed the conclusions drawn from an earlier transcriptomic analysis that the two mutants responded to CdS QD exposure differently both to the wild type and to each other. Just over half of the proteomic changes mirrored documented changes at the level of gene transcription, but a substantial number of transcript/gene product pairs were altered in the opposite direction. An interpretation of the discrepancies is given, along with some considerations regarding the use and significance of -omics when monitoring the potential toxicity of ENMs for health and environment. PMID:26732871

  10. Cadmium

    Integrated Risk Information System (IRIS)

    Cadmium ; CASRN 7440 - 43 - 9 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effects

  11. Ternary spinel cadmium stannate, cadmium indate, and zinc stannate and binary tin oxide and indium oxide transparent conducting oxides as front contact materials for cadmium sulfide/cadmium tellurium photovoltaic devices

    NASA Astrophysics Data System (ADS)

    Mamazza, Robert, Jr.

    Transparent conducting oxides (TCO's) of Cd2SnO 4 (cadmium stannate), CdIn2O4 (cadmium indate), and Zn2SnO4 (zinc stannate) thin films were investigated from a materials and applications point of view through. All films were deposited by co-sputtering using either binary oxide or metallic (reactive sputtering) targets. The film properties were investigated as a function of film composition and stoichiometry. The effect of process parameters such as deposition temperatures, and post-deposition heat treatments on the structural and electro-optical properties of the films were also investigated extensively. All as-deposited films were found to be amorphous independent of substrate deposition temperature. The electro-optical and crystallographic properties were heavily dependant on the post deposition heat treatments. Cd2SnO4, Zn 2SnO4, and CdIn2O4 all produced highly transparent films with average transmission values (400--900 nm range) of 92%, 93%, and 90%, respectively. Cd2SnO4 and CdIn 2O4 were highly conductive with resistivity values as low as 2.01 x 10-4 O-cm and 2.90 x 10 -4 O-cm, respectively. Conversely, Zn2SnO 4 was not able to produce highly conductive films, with the lowest resistivity being 4.3 x 10-3 O-cm. CdTe solar cells were fabricated using al the above materials as front contacts or as high-ρ layers in bi-layer structures. All cells were of the superstrate configuration: Low-ρ TCO/high-ρ TCO/CdS/CdTe/Back contact. Only the TCO layers were varied; the remainder of the device was held constant. In most cases the inclusion of a high-ρ TCO layer was found to improve solar cell performance, especially in regard to the open circuit voltage. Cd2SnO4 was the exception. The incorporation of Zn2SnO4 as a high-ρ layer enabled a greatest current collection from high energy wavelengths through an apparent thinning effect on the CdS. This increased the overall short circuit current density to values in excess of 24.9 mA/cm2. The standard device consisted of

  12. Porous copper zinc tin sulfide thin film as photocathode for double junction photoelectrochemical solar cells.

    PubMed

    Dai, Pengcheng; Zhang, Guan; Chen, Yuncheng; Jiang, Hechun; Feng, Zhenyu; Lin, Zhaojun; Zhan, Jinhua

    2012-03-21

    Porous copper zinc tin sulfide (CZTS) thin film was prepared via a solvothermal approach. Compared with conventional dye-sensitized solar cells (DSSCs), double junction photoelectrochemical cells using dye-sensitized n-type TiO(2) (DS-TiO(2)) as the photoanode and porous p-type CZTS film as the photocathode shows an increased short circuit current, external quantum efficiency and power conversion efficiency.

  13. Use of solar cell in electrokinetic remediation of cadmium-contaminated soil.

    PubMed

    Yuan, Songhu; Zheng, Zhonghua; Chen, Jing; Lu, Xiaohua

    2009-03-15

    This preliminary study used a solar cell, instead of direct current (DC) power supply, to generate electric field for electrokinetic (EK) remediation of cadmium-contaminated soil. Three EK tests were conducted and compared; one was conducted on a cloudy and rainy day with solar cell, one was conducted on a sunny day with solar cell and another was conducted periodically with DC power supply. It was found that the output potential of solar cell depended on daytime and was influenced by weather conditions; the applied potential in soil was affected by the output potential and weather conditions, and the current achieved by solar cell was comparable with that achieved by DC power supply. Solar cell could be used to drive the electromigration of cadmium in contaminated soil, and removal efficiency achieved by solar cell was comparable with that achieved by DC power supply. Compared with traditional DC power supply, using solar cell as power supply for EK remediation can greatly reduce energy expenditure. This study provided an alternative to improve the EK soil remediation and expanded the use of solar cell in environmental remediation.

  14. Inorganic-organic solar cells based on quaternary sulfide as absorber materials.

    PubMed

    Hong, Tiantian; Liu, Zhifeng; Yan, Weiguo; Liu, Junqi; Zhang, Xueqi

    2015-12-14

    We report a novel promising quaternary sulfide (CuAgInS) to serve as a semiconductor sensitizer material in the photoelectrochemical field. In this study, CuAgInS (CAIS) sulfide sensitized ZnO nanorods were fabricated on ITO substrates through a facile and low-cost hydrothermal chemical method and applied on photoanodes for solar cells for the first time. The component and stoichiometry were key factors in determining the photoelectric performance of CAIS sulfide, which were controlled by modulating their reaction time. ZnO/Cu0.7Ag0.3InS2 nanoarrays exhibit an enhanced optical and photoelectric performance and the power conversion efficiency of ITO/ZnO/Cu0.7Ag0.3InS2/P3HT/Pt solid-state solar cell was up to 1.80%. The remarkable performance stems from improved electron transfer, a higher efficiency of light-harvesting and appropriate band gap alignment at the interface of the ZnO/Cu0.7Ag0.3InS2 NTs. The research indicates that CAIS as an absorbing material has enormous potential in solar cell systems.

  15. Cadmium-sulfide crystallites in Cd-. gamma. -glutamyl peptide complexes from Lycopersicon and Daucus

    SciTech Connect

    Reese, R.N. ); Winge, D.R. )

    1989-04-01

    Hydroponically-grown tomato plants (Lycopersicon esculentum P. Mill. cv stone) and suspension-cultured carrot cells (Daucus carota L.) exposed to 100 {mu}M cadmium salts produced metal-{gamma}-glutamyl peptide complexes containing acid labile sulfur. The properties of the complexes resemble the Cd-{gamma}-glutamyl complexes from Schizosaccharomyces pombe and Candida glabrata, known to contain a CdS crystallite core. The crystallite core is stabilized by a coating of peptides of the general structure ({gamma}-Glu-Cys){sub n}-Gly. The Cd-peptide complexes contain predominantly peptides of n{sub 2}, n{sub 3}, n{sub 4} and n{sub 3}desGly. Zn-peptide complexes were also isolated from carrot cultures grown in MS medium supplemented with 2 mM Zn and cysteine. Results of preliminary characterization of these complexes are consistent with the presence of a colloidal particle similar to that of the Cd-complexes.

  16. Single-enzyme biomineralization of cadmium sulfide nanocrystals with controlled optical properties

    PubMed Central

    Dunleavy, Robert; Lu, Li; Kiely, Christopher J.; McIntosh, Steven; Berger, Bryan W.

    2016-01-01

    Nature has evolved several unique biomineralization strategies to direct the synthesis and growth of inorganic materials. These natural systems are complex, involving the interaction of multiple biomolecules to catalyze biomineralization and template growth. Herein we describe the first report to our knowledge of a single enzyme capable of both catalyzing mineralization in otherwise unreactive solution and of templating nanocrystal growth. A recombinant putative cystathionine γ-lyase (smCSE) mineralizes CdS from an aqueous cadmium acetate solution via reactive H2S generation from l-cysteine and controls nanocrystal growth within the quantum confined size range. The role of enzymatic nanocrystal templating is demonstrated by substituting reactive Na2S as the sulfur source. Whereas bulk CdS is formed in the absence of the enzyme or other capping agents, nanocrystal formation is observed when smCSE is present to control the growth. This dual-function, single-enzyme, aerobic, and aqueous route to functional material synthesis demonstrates the powerful potential of engineered functional material biomineralization. PMID:27118834

  17. Single-enzyme biomineralization of cadmium sulfide nanocrystals with controlled optical properties.

    PubMed

    Dunleavy, Robert; Lu, Li; Kiely, Christopher J; McIntosh, Steven; Berger, Bryan W

    2016-05-10

    Nature has evolved several unique biomineralization strategies to direct the synthesis and growth of inorganic materials. These natural systems are complex, involving the interaction of multiple biomolecules to catalyze biomineralization and template growth. Herein we describe the first report to our knowledge of a single enzyme capable of both catalyzing mineralization in otherwise unreactive solution and of templating nanocrystal growth. A recombinant putative cystathionine γ-lyase (smCSE) mineralizes CdS from an aqueous cadmium acetate solution via reactive H2S generation from l-cysteine and controls nanocrystal growth within the quantum confined size range. The role of enzymatic nanocrystal templating is demonstrated by substituting reactive Na2S as the sulfur source. Whereas bulk CdS is formed in the absence of the enzyme or other capping agents, nanocrystal formation is observed when smCSE is present to control the growth. This dual-function, single-enzyme, aerobic, and aqueous route to functional material synthesis demonstrates the powerful potential of engineered functional material biomineralization.

  18. Fluorescent properties of a hybrid cadmium sulfide-dendrimer nanocomposite and its quenching with nitromethane.

    PubMed

    Campos, Bruno B; Algarra, Manuel; Esteves da Silva, Joaquim C G

    2010-01-01

    A fluorescent hybrid cadmium sulphide quantum dots (QDs) dendrimer nanocomposite (DAB-CdS) synthesised in water and stable in aqueous solution is described. The dendrimer, DAB-G5 dendrimer (polypropylenimine tetrahexacontaamine) generation 5, a diaminobutene core with 64 amine terminal primary groups. The maximum of the excitation and emission spectra, Stokes' shift and the emission full width of half maximum of this nanocomposite are, respectively: 351, 535, 204 and 212 nm. The fluorescence time decay was complex and a four component decay time model originated a good fit (chi = 1.20) with the following lifetimes: tau (1) = 657 ps; tau (2) = 10.0 ns; tau (3) = 59.42 ns; and tau (4) = 265 ns. The fluorescence intensity of the nanocomposite is markedly quenched by the presence of nitromethane with a dynamic Stern-Volmer constant of 25 M(-1). The quenching profiles show that about 81% of the CdS QDs are located in the external layer of the dendrimer accessible to the quencher. PARAFAC analysis of the excitation emission matrices (EEM) acquired as function of the nitromethane concentration showed a trilinear data structure with only one linearly independent component describing the quenching which allows robust estimation of the excitation and emission spectra and of the quenching profiles. This water soluble and fluorescent nanocomposite shows a set of favourable properties to its use in sensor applications.

  19. Roles of hydrogen sulfide and nitric oxide in the alleviation of cadmium-induced oxidative damage in alfalfa seedling roots.

    PubMed

    Li, Le; Wang, Yanqin; Shen, Wenbiao

    2012-06-01

    Despite hydrogen sulfide (H(2)S) and nitric oxide (NO) are important endogenous signals or bioregulators involved in many vital aspects of plant growth and responses against abiotic stresses, little information was known about their interaction. In the present study, we evaluated the effects of H(2)S and NO on alfalfa (Medicago sativa L.) plants exposed to cadmium (Cd) stress. Pretreatment with an H(2)S donor sodium hydrosulfide (NaHS) and well-known NO donor sodium nitroprusside (SNP) decreased the Cd toxicity. This conclusion was supported by the decreases of lipid peroxidation as well as the amelioration of seedling growth inhibition and Cd accumulation, in comparison with the Cd-stressed alone plants. Total activities and corresponding transcripts of antioxidant enzymes, including superoxide dismutase, peroxidase and ascorbate peroxidase were modulated differentially, thus leading to the alleviation of oxidative damage. Effects of H(2)S above were reversed by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt (cPTIO), the specific scavenger of NO. By using laser confocal scanning microscope combined with Greiss reagent method, further results showed that NO production increased significantly after the NaHS pretreatment regardless of whether Cd was applied or not, all of which were obviously inhibited by cPTIO. These decreases of NO production were consistent with the exaggerated syndromes associated with Cd toxicity. Together, above results suggested that NO was involved in the NaHS-induced alleviation of Cd toxicity in alfalfa seedlings, and also indicated that there exists a cross-talk between H(2)S and NO responsible for the increased abiotic stress tolerance.

  20. A comparative study of the annealing behavior of Cu(In,Ga)(S,Se){sub 2} based solar cells with an indium sulfide buffer layer, partly submitted to wet chemical treatments

    SciTech Connect

    Hönes, C.; Hackenberg, J.; Zweigart, S.; Wachau, A.; Hergert, F.; Siebentritt, S.

    2015-03-07

    Indium sulfide thin films deposited via thermal evaporation from compound source material have been successfully utilized as a cadmium free buffer layer for Cu(In,Ga)Se{sub 2} based solar cells. However, high efficiencies are only reached after an additional annealing step. In this work, the annealing behavior of Cu(In,Ga)(S,Se){sub 2} based indium sulfide buffered solar cells is compared to the annealing behavior of similar cells, which were submitted to wet chemical treatments partly containing cadmium ions. Upon annealing a significant improvement of the initial solar cell characteristics is observed for the untreated cell and is related to the increase of activation energy for the carrier recombination process and a decrease of the ideality factor within the one diode model. It is shown here that this improvement can also be achieved by wet treatments of the absorber prior to buffer layer deposition. Upon annealing these treated cells still gain in collection length but lose open circuit voltage, which is explained here within a model including a highly p-doped absorber surface layer and supported by simulations showing that a decrease in doping density of such a surface layer would lead to the observed effects.

  1. Cinnamaldehyde Ameliorates Cadmium-Inhibited Root Elongation in Tobacco Seedlings via Decreasing Endogenous Hydrogen Sulfide Production.

    PubMed

    Ye, Xie-Feng; Xue, Yanfeng; Ling, Tianxiao; Wang, Yong; Yu, Xiao-Na; Cheng, Changxin; Feng, Guosheng; Hu, Liangbin; Shi, Zhiqi; Chen, Jian

    2016-12-24

    Cinnamaldehyde (CA) is natural plant-derived compound that has been highly appreciated for its medicinal properties. However, little information is known about the regulation of plant intrinsic physiology by CA. To address these gaps, physiological, histochemical, and biochemical approaches were applied to investigate CA-facilitated cadmium (Cd) tolerance in the roots of tobacco (Nicotiana tabacum) seedlings. Treatment with CdCl₂ at 20 μM for 72 h resulted in the significant decrease in root elongation by 40.39% as compared to control. CA alleviated Cd-inhibited root elongation in dose- and time-dependent manners. The addition of CA at 20 μM induced significant increase in root elongation by 42.58% as compared to Cd treatment alone. CA abolished Cd-induced ROS (reactive oxygen species) accumulation, lipid peroxidation, loss of membrane integrity, cell death, and free Cd(2+) accumulation in roots. CA blocked the Cd-induced increase in the endogenous H₂S level through the down-regulation of d-cysteine desulfhydrase (DCD) expression. H₂S scavenger hypotaurine (HT) or potent H₂S-biosynthetic inhibitor dl-propargylglicine (PAG) were able mimic the action of CA on the blockade of Cd-induced H₂S accumulation, cell death, and growth inhibition. Enhancement of the endogenous H₂S level with NaHS (H₂S donor) abrogated all the beneficial capabilities of CA, HT, and PAG. Collectively, these results suggest that CA has great potential to confer plant tolerance against Cd stress, which is closely associated with its capability to inhibit Cd-induced H₂S production. This study not only provides evidences for the regulation of plant physiology by CA but also sheds new light on the cross-talk between CA and H₂S in physiological modulations.

  2. Workshop proceedings: Photovoltaic conversion of solar energy for terrestrial applications. Volume 1: Working group and panel reports

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Technological aspects of solar energy conversion by photovoltaic cells are considered. The advantage of the single crystal silicon solar cell approach is developed through comparisons with polycrystalline silicon, cadmium sulfide/copper sulfide thin film cells, and other materials and devices.

  3. Intratracheal instillation of zinc-cadmium sulfide (ZnCdS) in Fischer 344 rats.

    PubMed

    Bergmann, J D; Metker, L W; McCain, W C; Beall, P A; Michie, M W; Lee, R B

    2000-04-01

    The purpose of this study was to assess the bioavailability and pulmonary toxicity of ZnCdS in rats. Groups of 30 male Fischer 344 rats each were anesthetized and dosed via intratracheal instillation with 5 mg of either ZnCdS, quartz (positive control), or titanium dioxide (TiO(2), negative control) suspended in 0.5 ml saline. A vehicle control group received 0.5 ml saline. Ten animals from each test group were sacrificed at 1 day, 1 wk, and 14 wk after dosing for bronchoalveolar lavage fluid (BALF) analysis and histopathology. The BALF was analyzed for alkaline phosphatase, acid phosphatase, lactate dehydrogenase (LDH), beta-glucuronidase (beta-glu), total protein, and cell counts. Two separate groups of 24 rats each were dosed as already described with either ZnCdS or saline. Eight rats from each group were sacrificed at 1 day, 1 wk, and 14 wk after dosing for determination of cadmium (Cd) and zinc (Zn) concentrations in the lung, liver, kidney, and blood. Results indicate that at 1 day after dosing, all enzyme activities (except acid phosphatase) and cell counts in BALF from the quartz and ZnCdS groups were significantly higher than in the TiO(2) and saline groups. At 7 days after dosing, high enzyme activity persisted in the quartz group, while the ZnCdS group showed only LDH and total protein levels significantly higher than the saline group. At 14 wk after dosing, LDH, total protein, beta-glu, and cell counts in the quartz group were significantly higher than all other groups. Histologic examination revealed interstitial inflammation and accumulation of foreign material in the lungs and mediastinal lymph nodes of quartz-, TiO(2)-, and ZnCdS-treated rats. Metal analyses in tissues showed profuse Cd and Zn concentrations in the lung 1 day after dosing, followed by a successive decline at 7 days and 14 wk after dosing. A very small, but statistically significant, amount of Cd and Zn was found in the kidneys at 14 wk after dosing. In conclusion, ZnCdS appears to

  4. Chemically deposited thin films of sulfides and selenides of antimony and bismuth as solar energy materials

    NASA Astrophysics Data System (ADS)

    Nair, M. T.; Nair, Padmanabhan K.; Garcia, V. M.; Pena, Y.; Arenas, O. L.; Garcia, J. C.; Gomez-Daza, O.

    1997-10-01

    Chemical bath deposition techniques for bismuth sulfide, bismuth selenide, antimony sulfide, and antimony selenide thin films of about 0.20 - 0.25 micrometer thickness are reported. All these materials may be considered as solar absorber films: strong optical absorption edges, with absorption coefficient, (alpha) , greater than 104 cm-1, are located at 1.31 eV for Bi2Se3, 1.33 eV for Bi2S3, 1.8 eV for Sb2S3, and 1.35 eV for Sb2Se3. As deposited, all the films are nearly amorphous. However, well defined crystalline peaks matching bismuthinite (JCPDS 17- 0320), paraguanajuatite (JCPDS 33-0214), and stibnite (JCPDS 6-0474) and antimony selenide (JCPDS 15-0861) for Bi2S3, Bi2Se3, Sb2S3 and Sb2Se3 respectively, are observed when the films are annealed in nitrogen at 300 degrees Celsius. This is accompanied by a substantial modification of the electrical conductivity in the films: from 10-7 (Omega) -1 cm-1 (in as prepared films) to 10 (Omega) -1 cm-1 in the case of bismuth sulfide and selenide films, and enhancement of photosensitivity in the case of antimony sulfide films. The chemical deposition of a CuS/CuxSe film on these Vx- VIy films and subsequent annealing at 300 degrees Celsius for 1 h at 1 torr of nitrogen leads to the formation of p-type films (conductivity of 1 - 100 (Omega) -1 cm-1) of multinary composition. Among these, the formation of Cu3BiS3 (JCPDS 9-0488) and Cu3SbS4 (JCPDS 35- 0581), CuSbS2 (JCPDS 35-0413) have been clearly detected. Solar energy applications of these films are suggested.

  5. Studies of rf sputtered zinc tellurium:nitrogen and cadmium sulfide for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Drayton, Jennifer

    Photovoltaics based on thin film semiconductors are a renewable energy source with possible widespread applications. Semiconducting thin films from the II-VI family have the capability of being excellent candidates for this application as they are n-type, like CdS, which can be used with CdTe, another II-VI material which is p-type, to form a p-n junction. Other II-VI materials can be doped p-type, as in the case of ZnTe:N, which can be used as part of a back contact to a CdTe-based single junction solar cell and also as part of a recombination junction in a CdTe-based tandem solar cell. This dissertation investigates the properties of reactively rf sputtered ZnTe:N films and examines structures that utilize ZnTe:N as part of a back contact or as part of a recombination junction. The use of optical emission spectroscopy to determine which excited species of the N2 molecule are present in the plasma during reactive sputtering of ZnTe:N is also investigated. The use of optical emission spectroscopy as a diagnostic tool to monitor film quality by identifying contaminants in the sputtering system is also presented. The optimization of deposition parameters for CdTe, CdS, and ZnTe:N films fabricated in a new deposition system is presented. The effort to improve the CdS layer by increasing its resistivity is explored. By changing the deposition parameters but not adding any dopant we attempted to deposit highly resistive polycrystalline CdS. The resistivity measurements led to the discovery that CdS exhibits piezoelectric properties when used in CdTe-based photovoltaics. These important properties, which had not been observed previously, will be presented and discussed.

  6. High-performance cadmium sulphide-based planar perovskite solar cell and the cadmium sulphide/perovskite interfaces

    NASA Astrophysics Data System (ADS)

    Peng, Haitao; Sun, Weihai; Li, Yunlong; Yan, Weibo; Yu, Pingrong; Zhou, Huanping; Bian, Zuqiang; Huang, Chunhui

    2016-04-01

    Planar heterojunction perovskite solar cell is one of the most competitive photovoltaic technologies, while charge transport materials play a crucial role. We successfully demonstrated an effective electron transport material, namely chemical bath deposited cadmium sulphide (CdS) film under low temperature, in perovskite-based solar cells. Power conversion efficiency of 16.1% has been achieved, which is comparable to that of devices based on TiO2 film prepared via low-temperature processes. Electronic impedance spectra reveal that the CdS-based device presents a higher recombination resistance than TiO2-based devices, which reduces carrier recombination and increases the open circuit voltage. The interface between CdS and perovskite was characterized with improved characteristics when compared to TiO2, e.g., efficient carrier extraction and reduced surface defect-associated degradation in the devices, which help to alleviate anomalous hysteresis and long-term instability. Furthermore, the entire device was fabricated via solution process with a processing temperature below 100°C, suggesting a promising method of further development of perovskite solar cells and commercial manufacturing.

  7. Cadmium telluride solar cells: Record-breaking voltages

    DOE PAGES

    Poplawsky, Jonathan D.

    2016-01-01

    Here, the performance of CdTe solar cells — cheaper alternatives to silicon photovoltaics — is hampered by their low output voltages, which are normally well below the theoretical limit. Now, record voltages of over 1 V have been reported in single-crystal CdTe heterostructure solar cells, which are close to those of benchmark GaAs cells.

  8. Cadmium telluride solar cells: Record-breaking voltages

    SciTech Connect

    Poplawsky, Jonathan D.

    2016-01-01

    Here, the performance of CdTe solar cells — cheaper alternatives to silicon photovoltaics — is hampered by their low output voltages, which are normally well below the theoretical limit. Now, record voltages of over 1 V have been reported in single-crystal CdTe heterostructure solar cells, which are close to those of benchmark GaAs cells.

  9. Cadmium sulfide/copper ternary heterojunction cell research semiannual report, 1 July 1983 - 31 December 1983

    SciTech Connect

    Devaney, W.E.; Mickelsen, R.A.; Chen, W.S.; Hsiao, Y.R.; Stewart, J.M.; Olsen, L.C.; Rothwarf, A.

    1984-05-01

    The properties of polycrystalline, thin-film CuInSe/sub 2//CdS and CdZnS solar cells prepared by vacuum evaporation techniques onto metallized alumina and glass substrates are described. Cells on glass substrates are reported to show higher V/sub oc/'s but lower I/sub sc/'s than alumina substrate cells. Preparations for the deposition of CuIn/sub 1-x/Ga/sub x/Se/sub 2/ films in a planetary apparatus and initial results on annealing of CuInSe/sub 2/ films in H/sub 2/Se environments are discussed. Thermally Stimulated Capacitance (TSCAP) and Isothermal Capacitance Transient Spectroscopy (ICTS) results on CuInSe/sub 2/ cells are reported. The development of film and device analysis techniques including SEM, EDS and EBIC are described and typical results are presented. Low temperature (12/sup 0/K) photoluminescence of CuInSe/sub 2/ films excited with a He-Ne laser is discussed along with a proposed energy level model. Finally, results are presented from two subcontractors (Drexel University and JCGS) pertaining to cell analysis and theoretical cell mechanism studies.

  10. Cadmium sulfide/copper ternary heterojunction cell research. Final report, January 8, 1979-June 7, 1980

    SciTech Connect

    Fleming, D. L.

    1980-01-01

    Dual source, Se and CuInSe/sub 2/, coevaporation and flash evaporation of stoichiometric CuInSe/sub 2/ powder were investigated to develop a process of fabricating large area CdS/CuInSe/sub 2/ heterojunction solar cells. CuInSe/sub 2/ was seen to decompose upon evaporation, producing layered films in the dual source system. Annealing of these films and alternative dual sources have been considered. Single phase p type films have been produced but no devices have been made from such films. Flash evaporation circumvents the decomposition problem, and if one bakes the powder to obtain a small Cu excess as well as getting a Se excess in the film, p type CuInSe/sub 2/ films can be obtained. A 1% efficient device of 6 cm/sup 2/ area was made using a flash evaporated CuInSe/sub 2/ film. Annealing studies and measurements of spatial uniformity of this device are reported.

  11. Yellow-light generation and engineering in zinc-doped cadmium sulfide nanobelts with low-threshold two-photon excitation.

    PubMed

    Wang, Xiaoxu; Li, Jing; Li, Qisong; Chen, Bingkun; Song, Guangli; Zhang, Wensheng; Shi, Lijie; Zou, Bingsuo; Liu, Ruibin

    2014-08-15

    Through a simple doping route with zinc ion as a dopant in cadmium sulfide nanobelts, a bright yellow-colored light was obtained. The detailed chromaticity and brightness of the light can be engineered by the dopant concentration and the pumping power, which are used to control the dominant wavelength to any fine yellow color, and even cover the sodium-yellow-line of 589 nm. The nanobelts were synthesized through a chemical vapor deposition method. The peak shift of the XRD result proves that the zinc ions as a dopant exist in the nanobelts rather than in the ZnCdS alloy formation. Time-resolved photoluminescence of the nanobelt reveals the existence of the defect-related state, which induces a red band to further mix with green band-edge emission to form the yellow light. Moreover, low-threshold two-photon excitation was observed in the proper Zn-doped cadmium sulfide nanobelts. The dopant and pumping power-tuned generation and engineering of the yellow light makes it possible to use this kind of material as yellow light-emitting source.

  12. Structural, photoconductivity and photoluminescence characterization of cadmium sulfide quantum dots prepared by a co-precipitation method

    NASA Astrophysics Data System (ADS)

    Mishra, Sheo K.; Srivastava, Rajneesh K.; Prakash, S. G.; Yadav, Raghvendra S.; Panday, A. C.

    2011-03-01

    In this paper, cadmium sulfide (CdS) quantum dots (QDs) are synthesized by a simple co-precipitation method. X-ray diffraction (XRD) confirmed the formation of a cubical zinc blend structure of CdS nanoparticles. Transmission Electron Microscopy (TEM) images revealed that the CdS QDs are of 2-5 nm in size. The UV-vis absorption spectra showed an absorption peak at 427 nm (˜2.90 eV) indicating a blue shift of 0.48 eV as compared to bulk CdS. We estimated the particle sizes with the help of X-ray diffraction (XRD) patterns (3.665 nm) and the shift of the band gap absorption in the UV-vis spectrum (4.276 nm), which is very close to the TEM micrograph result. The photoluminescence spectrum shows three major emission peaks centered at 453 nm (˜2.73 eV), 526 nm (˜2.35 eV) and 551 nm (˜2.24 eV) at room temperature, which may be attributed to excitonic transitions, donor-acceptor (D-A) pairs recombination and the sulphur interstitial defects (Is) present in the band gap. To study the photoconductivity, the field dependence of the photocurrent and the dark-current was assessed, as was the time-resolved rise and decay photocurrent spectrum and wavelength-dependence photocurrent spectrum assessment of the CdS QDs. The time-resolved rise and decay photocurrent spectra exhibited negative photoconductivity (NPC) behavior when the CdS QDs were illuminated with 490 nm light. Such anomalous NPC may be attributed to the light-induced desorption of water molecules. The wavelength-dependence of the photocurrent was found to be close to the absorption and PL spectrum. The photoconductivity properties of the CdS QDs were measured using a thick film of powder without any binder. These CdS QDs can find potential application in optoelectronic devices and photodetectors.

  13. Device Engineering Towards Improved Tin Sulfide Solar Cell Performance and Performance Reproducibility

    SciTech Connect

    Steinmann, Vera; Chakraborty, Rupak; Rekemeyer, Paul; Siol, Sebastian; Martinot, Loic; Polizzotti, Alex; Yang, Chuanxi; Hartman, Katy; Gradecak, Silvija; Zakutayev, Andriy; Gordon, Roy G.; Buonassisi, Tonio

    2016-11-21

    As novel absorber materials are developed and screened for their photovoltaic (PV) properties, the challenge remains to rapidly test promising candidates in high-performing PV devices. There is a need to engineer new compatible device architectures, including the development of novel transparent conductive oxides and buffer layers. Here, we consider the two approaches of a substrate-style and a superstrate-style device architecture for novel thin-film solar cells. We use tin sulfide as a test absorber material. Upon device engineering, we demonstrate new approaches to improve device performance and performance reproducibility.

  14. Direct Synthesis of Novel and Reactive Sulfide-modified Nano Iron through Nanoparticle Seeding for Improved Cadmium-Contaminated Water Treatment.

    PubMed

    Su, Yiming; Adeleye, Adeyemi S; Huang, Yuxiong; Zhou, Xuefei; Keller, Arturo A; Zhang, Yalei

    2016-04-20

    Magnetic sulfide-modified nanoscale zerovalent iron (S-nZVI) is of great technical and scientific interest because of its promising application in groundwater remediation, although its synthesis is still a challenge. We develop a new nanoparticle seeding method to obtain a novel and reactive nanohybrid, which contains an Fe(0) core covered by a highly sulfidized layer under high extent of sulfidation. Syntheses monitoring experiments show that seeding accelerates the reduction rate from Fe(2+) to Fe(0) by 19%. X-ray adsorption near edge structure (XANES) spectroscopy and extended X-ray absorption fine structure analyses demonstrate the hexahedral Fe-Fe bond (2.45 and 2.83 Å) formation through breaking down of the 1.99 Å Fe-O bond both in crystalline and amorphous iron oxide. The XANES analysis also shows 24.2% (wt%) of FeS with bond length of 2.4 Å in final nanohybrid. Both X-ray diffraction and Mössbauer analyses further confirm that increased nanoparticle seeding results in formation of more Fe(0) crystals. Nano-SiO2 seeding brings down the size of single Fe(0) grain from 32.4 nm to 18.7 nm, enhances final Fe(0) content from 5.9% to 55.6%, and increases magnetization from 4.7 to 65.5 emu/g. The synthesized nanohybrid has high cadmium removal capacity and holds promising prospects for treatment of metal-contaminated water.

  15. Improved performance of silicon nanowire/cadmium telluride quantum dots/organic hybrid solar cells

    NASA Astrophysics Data System (ADS)

    Ge, Zhaoyun; Xu, Ling; Zhang, Renqi; Xue, Zhaoguo; Wang, Hongyu; Xu, Jun; Yu, Yao; Su, Weining; Ma, Zhongyuan; Chen, Kunji

    2015-04-01

    We fabricated silicon nanowire/cadmium telluride quantum dots (CdTe QDs)/organic hybrid solar cells and investigated their structure and electrical properties. Transmission electron microscope revealed that CdTe QDs were uniformly distributed on the surface of the silicon nanowires, which made PEDOT:PSS easily filled the space between SiNWs. The current density-voltage (J-V) characteristics of hybrid solar cells were investigated both in dark and under illumination. The result shows that the performance of the hybrid solar cells with CdTe QDs layer has an obvious improvement. The optimal short-circuit current density (Jsc) of solar cells with CdTe QDs layer can reach 33.5 mA/cm2. Compared with the solar cells without CdTe QDs, Jsc has an increase of 15.1%. Power conversion efficiency of solar cells also increases by 28.8%. The enhanced performance of the hybrid solar cells with CdTe QDs layers are ascribed to down-shifting effect of CdTe QDs and the modification of the silicon nanowires surface with CdTe QDs. The result of our experiments suggests that hybrid solar cells with CdTe QDs modified are promising candidates for solar cell application.

  16. An integrated photoelectrochemical-chemical loop for solar-driven overall splitting of hydrogen sulfide.

    PubMed

    Zong, Xu; Han, Jingfeng; Seger, Brian; Chen, Hongjun; Lu, Gaoqing Max; Li, Can; Wang, Lianzhou

    2014-04-22

    Abundant and toxic hydrogen sulfide (H2 S) from industry and nature has been traditionally considered a liability. However, it represents a potential resource if valuable H2 and elemental sulfur can be simultaneously extracted through a H2 S splitting reaction. Herein a photochemical-chemical loop linked by redox couples such as Fe(2+) /Fe(3+) and I(-) /I3 (-) for photoelectrochemical H2 production and H2 S chemical absorption redox reactions are reported. Using functionalized Si as photoelectrodes, H2 S was successfully split into elemental sulfur and H2 with high stability and selectivity under simulated solar light. This new conceptual design will not only provide a possible route for using solar energy to convert H2 S into valuable resources, but also sheds light on some challenging photochemical reactions such as CH4 activation and CO2 reduction. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Improved performance of quantum dot-sensitized solar cells adopting a highly efficient cobalt sulfide/nickel sulfide composite thin film counter electrode

    NASA Astrophysics Data System (ADS)

    Kim, Hee-Je; Kim, Su-Weon; Gopi, Chandu V. V. M.; Kim, Soo-Kyoung; Rao, S. Srinivasa; Jeong, Myeong-Soo

    2014-12-01

    Cobalt sulfide (CoS), nickel sulfide (NiS), and cobalt sulfide/nickel sulfide (CoS/NiS) were deposited onto fluorine-doped tin oxide (FTO) substrate using a facile chemical bath deposition method and utilized as counter electrodes (CEs) for polysulfide redox reactions in CdS/CdSe quantum dot-sensitized solar cells (QDSSCs). The thickness of 750 nm and 695 nm are optimized for NiS and CoS electrodes to prepare the CoS/NiS CE. Compared to a platinum (Pt) electrode, the CoS, NiS, and composite CoS/NiS electrodes provide higher electrocatalytic activity and lower charge-transfer resistance. The combination of a QDSSC with composite CoS/NiS CE shows an improved power conversion efficiency of 3.40% under the illumination of one sun (100 mW cm-2), which is higher than the CoS (2.53%), NiS (2.61%), and Pt (1.47%) CEs. This enhancement is mainly attributed to the NiS nanoparticles deposited on CoS film, due to which the composite structure exhibits a lower charge transfer resistance (7.61 Ω) at the interface of the CE and the electrolyte, along with superior electrochemical catalytic ability. This is well supported by the cyclic voltammetry, electrochemical impedance spectroscopy, and Tafel polarization measurements.

  18. Photoemf in cadmium sulfide

    NASA Technical Reports Server (NTRS)

    Boeer, K. W.

    1971-01-01

    Theoretical and experimental investigations on CdS single crystals and CuxS:CdS photovoltaic cells prepared from CdS single crystals by a chemical-dip procedure are described. The studies are aimed at clarifying cell mechanisms which affect key cell properties (efficiency, reliability, and lifetime) by examining the properties of intrinsic and extrinsic defects in the junction and surface regions and their effects on carrier transport through these regions. The experimental research described includes studies of thermal, infrared, and field quenching of acceptor-doped CdS crystals; investigation of optical and electrical properties of CuxS:CdS photovoltaic cells (current-voltage characteristics, spectral distribution of photocurrent and photovoltage) and the dependence of these properties on temperature and light intensity; measurement of changes, as a result of heat treatment in ultrahigh vacuum, in the spectral distribution of photoconductivity at room temperature and liquid nitrogen temperature, the luminescence spectrum at liquid nitrogen temperature, and the thermally stimulated current curves of CdS crystals; determination of the effect of irradiation with 150 keV (maximum) X-rays on the spectral distribution of photoconductivity and thermally-stimulated current of CdS crystals; and studies of the effect of growth conditions on the photoconductive properties of CdS crystals.

  19. Photoluminescence Excitation Spectroscopy Characterization of Cadmium Telluride Solar Cells

    SciTech Connect

    Moore, James E.; Wang, Xufeng; Grubbs, Elizabeth K.; Drayton, Jennifer; Johnston, Steve; Levi, Dean; Lundstrom, Mark S.; Bermel, Peter

    2016-11-21

    The use of steady-state photoluminescence spectroscopy as a contactless characterization tool, suitable for inline optical characterization, has been previously demonstrated for high efficiency solar cells such as GaAs. In this paper, we demonstrate the use of PLE characterization on a thin film CdS/CdTe np heterojunction solar cell, and compare the results to measured EQE and I-V data. In contrast to previous work on high-quality GaAs, the PLE and EQE spectra do not match closely here. We still find, however, that reliable material parameters can be extracted from the PLE measurements. We also provide a physical explanation of the limits defining the cases when the PLE and EQE spectra may be expected to match.

  20. Two-Dimensional Cadmium Chloride Nanosheets in Cadmium Telluride Solar Cells

    DOE PAGES

    Perkins, Craig L.; Beall, Carolyn; Reese, Matthew O.; ...

    2017-05-12

    In this paper we make use of a liquid nitrogen-based thermomechanical cleavage technique and a surface analysis cluster tool to probe in detail the tin oxide/emitter interface at the front of completed CdTe solar cells. We show that this thermomechanical cleavage occurs within a few angstroms of the SnO2/emitter interface. An unexpectedly high concentration of chlorine at this interface, ~20%, was determined from a calculation that assumed a uniform chlorine distribution. Angle-resolved X-ray photoelectron spectroscopy was used to further probe the structure of the chlorine-containing layer, revealing that both sides of the cleave location are covered by one-third of amore » unit cell of pure CdCl2, a thickness corresponding to about one Cl-Cd-Cl molecular layer. We interpret this result in the context of CdCl2 being a true layered material similar to transition-metal dichalcogenides. Exposing cleaved surfaces to water shows that this Cl-Cd-Cl trilayer is soluble, raising questions pertinent to cell reliability. Our work provides new and unanticipated details about the structure and chemistry of front surface interfaces and should prove important to improving materials, processes, and reliability of next-generation CdTe-based solar cells.« less

  1. Heterogeneous Bimetallic Phosphide/Sulfide Nanocomposite for Efficient Solar-Energy-Driven Overall Water Splitting.

    PubMed

    Xin, Yanmei; Kan, Xiang; Gan, Li-Yong; Zhang, Zhonghai

    2017-09-14

    Solar-driven overall water splitting is highly desirable for hydrogen generation with sustainable energy sources, which need efficient, earth-abundant, robust, and bifunctional electrocatalysts for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Herein, we propose a heterogeneous bimetallic phosphide/sulfide nanocomposite electrocatalyst of NiFeSP on nickel foam (NiFeSP/NF), which shows superior electrocatalytic activity of low overpotentials of 91 mV at -10 mA cm(-2) for HER and of 240 mV at 50 mA cm(-2) for OER in 1 M KOH solution. In addition, the NiFeSP/NF presents excellent overall water splitting performance with a cell voltage as low as 1.58 V at a current density of 10 mA cm(-2). Combining with a photovoltaic device of a Si solar cell or integrating into photoelectrochemical (PEC) systems, the bifunctional NiFeSP/NF electrocatalyst implements unassisted solar-driven water splitting with a solar-to-hydrogen conversion efficiency of ∼9.2% and significantly enhanced PEC performance, respectively.

  2. Thin film cadmium telluride solar cells. Final technical report for period July 1, 1979-August 31, 1980

    SciTech Connect

    Chu, T.L.

    1980-08-01

    The objectives of this contract are to investigate thin films of cadmium telluride on low cost substrates and to determine the feasibility of using these films for high efficiency solar cells. Efforts during this program have been directed to the construction of apparatus for the chemical vapor deposition of cadmium telluride films, the selection and preparation of substrates, the deposition and characterization of cadmium telluride films, and the fabrication and characterization of solar cells. Cadmium telluride films have been deposited on a number of substrates by the direct combination of cadmium and tellurium on the substrate surface at 500/sup 0/C or higher at rates of up to 0.6 ..mu..m/min. The structural, crystallographic, and electrical properties of cadmium telluride films deposited over a wide range of conditions have been evaluated. A series of doping experiments have been carried out using iodine and indium as the n-type dopant, and phosphorus, arsenic, and antimony as the p-type dopant. Low resistivity films have not been produced thus far. In/W/graphite substrates have been used for the deposition of n-type films with an ohmic interface. However, no suitable substrates have been found to form an ohmic interface with p-type films. Solar cells prepared from these films exhibit relatively good short-circuit current density, up to 15 mA/cm/sup 2/, but their conversion efficiencies are severely limited by the high series resistance of the devices.

  3. Workshop proceedings: Photovoltaic conversion of solar energy for terrestrial applications. Volume 2: Invited papers

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A photovoltaic device development plan is reported that considers technological as well as economical aspects of single crystal silicon, polycrystal silicon, cadmium sulfide/copper sulfide thin films, as well as other materials and devices for solar cell energy conversion systems.

  4. Leaching of cadmium and tellurium from cadmium telluride (CdTe) thin-film solar panels under simulated landfill conditions

    PubMed Central

    Ramos-Ruiz, Adriana; Wilkening, Jean V.; Field, James A.; Sierra-Alvarez, Reyes

    2017-01-01

    A crushed non-encapsulated CdTe thin-film solar cell was subjected to two standardized batch leaching tests (i.e., Toxicity Characteristic Leaching Procedure (TCLP) and California Waste Extraction Test (WET)) and to a continuous-flow column test to assess cadmium (Cd) and tellurium (Te) dissolution under conditions simulating the acidic- and the methanogenic phases of municipal solid waste landfills. Low levels of Cd and Te were solubilized in both batch leaching tests (<8.2% and <3.6% of added Cd and Te, respectively). On the other hand, over the course of 30 days, 73% of the Cd and 21% of the Te were released to the synthetic leachate of a continuous-flow column simulating the acidic landfill phase. The dissolved Cd concentration was 3.24-fold higher than the TCLP limit (1 mg L-1), and 650-fold higher than the maximum contaminant level established by the US-EPA for this metal in drinking water (0.005 mg L-1). In contrast, the release of Cd and Te to the effluent of the continuous-flow column simulating the methanogenic phase of a landfill was negligible. The remarkable difference in the leaching behavior of CdTe in the columns is related to different aqueous pH and redox conditions promoted by the microbial communities in the columns, and is in agreement with thermodynamic predictions. PMID:28472709

  5. Leaching of cadmium and tellurium from cadmium telluride (CdTe) thin-film solar panels under simulated landfill conditions.

    PubMed

    Ramos-Ruiz, Adriana; Wilkening, Jean V; Field, James A; Sierra-Alvarez, Reyes

    2017-08-15

    A crushed non-encapsulated CdTe thin-film solar cell was subjected to two standardized batch leaching tests (i.e., Toxicity Characteristic Leaching Procedure (TCLP) and California Waste Extraction Test (WET)) and to a continuous-flow column test to assess cadmium (Cd) and tellurium (Te) dissolution under conditions simulating the acidic- and the methanogenic phases of municipal solid waste landfills. Low levels of Cd and Te were solubilized in both batch leaching tests (<8.2% and <3.6% of added Cd and Te, respectively). On the other hand, over the course of 30days, 73% of the Cd and 21% of the Te were released to the synthetic leachate of a continuous-flow column simulating the acidic landfill phase. The dissolved Cd concentration was 3.24-fold higher than the TCLP limit (1mgL(-1)), and 650-fold higher than the maximum contaminant level established by the US-EPA for this metal in drinking water (0.005mgL(-1)). In contrast, the release of Cd and Te to the effluent of the continuous-flow column simulating the methanogenic phase of a landfill was negligible. The remarkable difference in the leaching behavior of CdTe in the columns is related to different aqueous pH and redox conditions promoted by the microbial communities in the columns, and is in agreement with thermodynamic predictions. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Effects of piezoelectricity on cadmium sulphide-copper sulphide solar cells

    SciTech Connect

    Bennett, M.S.

    1981-01-01

    Theoretical calculations of the effects of applied uniform and non-uniform stresses on copper sulphide-cadmium sulphide solar cells predict that uniform stress will not affect their performance, while non-uniform stress will. Changes in open-circuit voltage and capacitance resulting from piezoelectric effects are predicted to be proportional to the divergence of the piezoelectric polarization. Experiments performed on single crystal cells verified these calculations for uniform stresses, and for a particular non-uniform stress (uniaxial bending). The changes in the latter case were less than 1%. These experiments were extended to determine the growth face of crystallites in polycrystalline cells.

  7. Carbon nanotube/metal-sulfide composite flexible electrodes for high-performance quantum dot-sensitized solar cells and supercapacitors

    PubMed Central

    Muralee Gopi, Chandu V. V.; Ravi, Seenu; Rao, S. Srinivasa; Eswar Reddy, Araveeti; Kim, Hee-Je

    2017-01-01

    Carbon nanotubes (CNT) and metal sulfides have attracted considerable attention owing to their outstanding properties and multiple application areas, such as electrochemical energy conversion and energy storage. Here we describes a cost-effective and facile solution approach to the preparation of metal sulfides (PbS, CuS, CoS, and NiS) grown directly on CNTs, such as CNT/PbS, CNT/CuS, CNT/CoS, and CNT/NiS flexible electrodes for quantum dot-sensitized solar cells (QDSSCs) and supercapacitors (SCs). X-ray photoelectron spectroscopy, X-ray diffraction, and transmission electron microscopy confirmed that the CNT network was covered with high-purity metal sulfide compounds. QDSSCs equipped with the CNT/NiS counter electrode (CE) showed an impressive energy conversion efficiency (η) of 6.41% and remarkable stability. Interestingly, the assembled symmetric CNT/NiS-based polysulfide SC device exhibited a maximal energy density of 35.39 W h kg−1 and superior cycling durability with 98.39% retention after 1,000 cycles compared to the other CNT/metal-sulfides. The elevated performance of the composites was attributed mainly to the good conductivity, high surface area with mesoporous structures and stability of the CNTs and the high electrocatalytic activity of the metal sulfides. Overall, the designed composite CNT/metal-sulfide electrodes offer an important guideline for the development of next level energy conversion and energy storage devices. PMID:28422182

  8. Carbon nanotube/metal-sulfide composite flexible electrodes for high-performance quantum dot-sensitized solar cells and supercapacitors

    NASA Astrophysics Data System (ADS)

    Muralee Gopi, Chandu V. V.; Ravi, Seenu; Rao, S. Srinivasa; Eswar Reddy, Araveeti; Kim, Hee-Je

    2017-04-01

    Carbon nanotubes (CNT) and metal sulfides have attracted considerable attention owing to their outstanding properties and multiple application areas, such as electrochemical energy conversion and energy storage. Here we describes a cost-effective and facile solution approach to the preparation of metal sulfides (PbS, CuS, CoS, and NiS) grown directly on CNTs, such as CNT/PbS, CNT/CuS, CNT/CoS, and CNT/NiS flexible electrodes for quantum dot-sensitized solar cells (QDSSCs) and supercapacitors (SCs). X-ray photoelectron spectroscopy, X-ray diffraction, and transmission electron microscopy confirmed that the CNT network was covered with high-purity metal sulfide compounds. QDSSCs equipped with the CNT/NiS counter electrode (CE) showed an impressive energy conversion efficiency (η) of 6.41% and remarkable stability. Interestingly, the assembled symmetric CNT/NiS-based polysulfide SC device exhibited a maximal energy density of 35.39 W h kg-1 and superior cycling durability with 98.39% retention after 1,000 cycles compared to the other CNT/metal-sulfides. The elevated performance of the composites was attributed mainly to the good conductivity, high surface area with mesoporous structures and stability of the CNTs and the high electrocatalytic activity of the metal sulfides. Overall, the designed composite CNT/metal-sulfide electrodes offer an important guideline for the development of next level energy conversion and energy storage devices.

  9. Atomic layer deposition of titanium sulfide and its application in extremely thin absorber solar cells

    SciTech Connect

    Mahuli, Neha; Sarkar, Shaibal K.

    2015-01-15

    Atomic layer deposition (ALD) of TiS{sub 2} is investigated with titanium tetrachloride and hydrogen sulfide precursors. In-situ quartz crystal microbalance and ex-situ x-ray reflectivity measurements are carried out to study self-limiting deposition chemistry and material growth characteristics. The saturated growth rate is found to be ca. 0.5 Å/cycle within the ALD temperature window of 125–200 °C. As grown material is found poorly crystalline. ALD grown TiS{sub 2} is applied as a photon harvesting material for solid state sensitized solar cells with TiO{sub 2} as electron transport medium. Initial results with Spiro-OMeTAD as hole conducting layer show ca. 0.6% energy conversion efficiency under 1 sun illumination.

  10. Impact of Sodium Contamination in Tin Sulfide Thin-Film Solar Cells

    DOE PAGES

    Steinmann, Vera; Brandt, Riley E.; Chakraborty, Rupak; ...

    2016-02-12

    Empirical observations show that sodium(Na) is a benign contaminant in some thin-filmsolar cells. Here, we intentionally contaminate thermally evaporated tin sulfide (SnS)thin-films with sodium and measure the SnS absorber properties and solar cellcharacteristics. The carrier concentration increases from 2 × 1016 cm-3 to 4.3 × 1017 cm-3 in Na-doped SnSthin-films, when using a 13 nm NaCl seed layer, which is detrimental for SnS photovoltaic applications but could make Na-doped SnS an attractive candidate in thermoelectrics. We observed trends in carrier concentration and found that it is in good agreement with density functional theory calculations, which predict an acceptor-type NaSn defectmore » with low formation energy.« less

  11. Direct Synthesis of Novel and Reactive Sulfide-modified Nano Iron through Nanoparticle Seeding for Improved Cadmium-Contaminated Water Treatment

    PubMed Central

    Su, Yiming; Adeleye, Adeyemi S.; Huang, Yuxiong; Zhou, Xuefei; Keller, Arturo A.; Zhang, Yalei

    2016-01-01

    Magnetic sulfide-modified nanoscale zerovalent iron (S-nZVI) is of great technical and scientific interest because of its promising application in groundwater remediation, although its synthesis is still a challenge. We develop a new nanoparticle seeding method to obtain a novel and reactive nanohybrid, which contains an Fe(0) core covered by a highly sulfidized layer under high extent of sulfidation. Syntheses monitoring experiments show that seeding accelerates the reduction rate from Fe2+ to Fe0 by 19%. X-ray adsorption near edge structure (XANES) spectroscopy and extended X-ray absorption fine structure analyses demonstrate the hexahedral Fe-Fe bond (2.45 and 2.83 Å) formation through breaking down of the 1.99 Å Fe-O bond both in crystalline and amorphous iron oxide. The XANES analysis also shows 24.2% (wt%) of FeS with bond length of 2.4 Å in final nanohybrid. Both X-ray diffraction and Mössbauer analyses further confirm that increased nanoparticle seeding results in formation of more Fe0 crystals. Nano-SiO2 seeding brings down the size of single Fe0 grain from 32.4 nm to 18.7 nm, enhances final Fe0 content from 5.9% to 55.6%, and increases magnetization from 4.7 to 65.5 emu/g. The synthesized nanohybrid has high cadmium removal capacity and holds promising prospects for treatment of metal-contaminated water. PMID:27095387

  12. Direct Synthesis of Novel and Reactive Sulfide-modified Nano Iron through Nanoparticle Seeding for Improved Cadmium-Contaminated Water Treatment

    NASA Astrophysics Data System (ADS)

    Su, Yiming; Adeleye, Adeyemi S.; Huang, Yuxiong; Zhou, Xuefei; Keller, Arturo A.; Zhang, Yalei

    2016-04-01

    Magnetic sulfide-modified nanoscale zerovalent iron (S-nZVI) is of great technical and scientific interest because of its promising application in groundwater remediation, although its synthesis is still a challenge. We develop a new nanoparticle seeding method to obtain a novel and reactive nanohybrid, which contains an Fe(0) core covered by a highly sulfidized layer under high extent of sulfidation. Syntheses monitoring experiments show that seeding accelerates the reduction rate from Fe2+ to Fe0 by 19%. X-ray adsorption near edge structure (XANES) spectroscopy and extended X-ray absorption fine structure analyses demonstrate the hexahedral Fe-Fe bond (2.45 and 2.83 Å) formation through breaking down of the 1.99 Å Fe-O bond both in crystalline and amorphous iron oxide. The XANES analysis also shows 24.2% (wt%) of FeS with bond length of 2.4 Å in final nanohybrid. Both X-ray diffraction and Mössbauer analyses further confirm that increased nanoparticle seeding results in formation of more Fe0 crystals. Nano-SiO2 seeding brings down the size of single Fe0 grain from 32.4 nm to 18.7 nm, enhances final Fe0 content from 5.9% to 55.6%, and increases magnetization from 4.7 to 65.5 emu/g. The synthesized nanohybrid has high cadmium removal capacity and holds promising prospects for treatment of metal-contaminated water.

  13. Annealed single-crystal cadmium selenide electrodes in liquid junction solar cells

    SciTech Connect

    Wessel, S.; Colbow, K.; Mackintosh, A.

    1984-12-01

    I-V characteristics, voltage dependence of the quantum efficiency, and spectral response were compared for annealed single-crystal CdSe photoanodes. Annealing in cadmium atmosphere improved the overall solar response considerably, while annealing under vacuum revealed a poor response for photon energies larger than 1.8 eV and a high quantum efficiency for near-bandgap energies. This behavior may be attributed to electron-hole pai generation from interbandgap states and a large density of minority carrier recombination centers near the crystal surface, owing to a high nonstoichiometry and a selenium layer at the surface. Annealing in selenium atmosphere resulted in very poor solar response caused by compensation. Simultaneous illumination of the electrodes with a He-Ne lase strongly enhanced the quantum efficiency for vacuum-annealed crystals for near-bandgap photons. We attribute this to electron trapping in the selenium-rich surface, with a resulting increase in depletion-layer width in the cadmium selenide.

  14. Lead-Sulfide-Selenide Quantum Dots and Gold-Copper Alloy Nanoparticles Augment the Light-Harvesting Ability of Solar Cells.

    PubMed

    Das, Aparajita; Deepa, Melepurath; Ghosal, Partha

    2017-01-10

    Lead-sulfide-selenide (PbSSe) quantum dots (QDs) and gold-copper (AuCu) alloy nanoparticles (NPs) were incorporated into a cadmium sulfide (CdS)/titanium oxide (TiO2 ) photoanode for the first time to achieve enhanced conversion of solar energy into electricity. PbSSe QDs with a band gap of 1.02 eV extend the light-harvesting range of the photoanode from the visible region to the near-infrared region. The conduction band (CB) edge of the PbSSe QDs is wedged between the CBs of TiO2 and CdS; this additional level coupled with the good electrical conductivity of the dots facilitate charge transport and collection, and a high power conversion efficiency (PCE) of 4.44 % is achieved for the champion cell with the TiO2 /PbSSe/CdS electrode. Upon including AuCu alloy NPs in the QD-sensitized electrodes, light absorption is enhance by plasmonic and light-scattering effects and also by the injection of hot electrons to the CBs of the QDs. Comparison of the incident photon-to-current conversion efficiency enhancement factors in addition to fluorescence decay and impedance studies reveal that the PbSSe QDs and AuCu alloy NPs promote charge injection to the current collector and increase the photogenerated charges produced, which thus enables the TiO2 /PbSSe/CdS/AuCu cell to deliver the highest PCE of 5.26 % among all the various photoanode compositions used.

  15. Single-material zinc sulfide bi-layer antireflection coatings for GaAs solar cells.

    PubMed

    Leem, Jung Woo; Jun, Dong-Hwan; Heo, Jonggon; Park, Won-Kyu; Park, Jin-Hong; Cho, Woo Jin; Kim, Do Eok; Yu, Jae Su

    2013-09-09

    We demonstrated the efficiency improvement of GaAs single-junction (SJ) solar cells with the single-material zinc sulfide (ZnS) bi-layer based on the porous/dense film structure, which was fabricated by the glancing angle deposition (GLAD) method, as an antireflection (AR) coating layer. The porous ZnS film with a low refractive index was formed at a high incident vapor flux angle of 80° in the GLAD. Each optimum thickness of ZnS bi-layer was determined by achieving the lowest solar weighted reflectance (SWR) using a rigorous coupled-wave analysis method in the wavelength region of 350-900 nm, extracting the thicknesses of 20 and 50 nm for dense and porous films, respectively. The ZnS bi-layer with a low SWR of ~5.8% considerably increased the short circuit current density (J(sc)) of the GaAs SJ solar cell to 25.57 mA/cm(2), which leads to a larger conversion efficiency (η) of 20.61% compared to the conventional one without AR layer (i.e., SWR~31%, J(sc) = 18.81 mA/cm(2), and η = 14.82%). Furthermore, after the encapsulation, its J(sc) and η values were slightly increased to 25.67 mA/cm(2) and 20.71%, respectively. For the fabricated solar cells, angle-dependent reflectance properties and external quantum efficiency were also studied.

  16. "Counterdoping" and Tuning of the Near Infrared Plasmonics in Non Stoichiometric Copper Sulfide for Solar Cell Application

    NASA Astrophysics Data System (ADS)

    Beynis, Christian

    Copper Sulfide Cu2S has attracted much attention as a p-type material for solar cell application in the early eighties, although the inevitable degradation occurring through air exposition has plummeted the interest for such semiconductors. Throughout this thesis, we have reviewed and elucidated the major reasons for such degradation. The "counterdoping" of non stoichiometric copper sulfide CuxS has been proposed to remedy this problem, using simple one pot low temperature syntheses under Nitrogen atmosphere. To assess the success of the technique, comparisons with stoichiometric and non stoichiometric Copper Indium Sulfide quantum dots grown under similar conditions has been proposed. Also the Localized Surface Plasmon Resonance (LSPR) of the semiconductor has been monitored as an indication of the carrier density in the quantum dots. Here, to single out the effects of the carrier concentration on the LSPR, STEM, NIR and UV-vis sprectroscopy, Photoluminescence (PL), EDS as well as XRD measurements has been conducted to support our thesis.

  17. Synthesis of Copper-Antimony-Sulfide Nanocrystals for Solution-Processed Solar Cells.

    PubMed

    Suehiro, Satoshi; Horita, Keisuke; Yuasa, Masayoshi; Tanaka, Tooru; Fujita, Katsuhiko; Ishiwata, Yoichi; Shimanoe, Kengo; Kida, Tetsuya

    2015-08-17

    The p-type nanocrystals (NCs) of copper-based chalcogenides, such as CuInSe2 and Cu2ZnSnS4, have attracted increasing attention in photovoltaic applications due to their potential to produce cheap solution-processed solar cells. Herein, we report the synthesis of copper-antimony-sulfide (CAS) NCs with different crystal phases including CuSbS2, Cu3SbS4, and Cu12Sb4S13. In addition, their morphology, crystal phase, and optical properties were characterized using transmission electron microscopy, X-ray diffractometry, UV-vis-near-IR spectroscopy, and photoemission yield spectroscopy. The morphology, crystal phase, and electronic structure were significantly dependent on the chemical composition in the CAS system. Devices were fabricated using particulate films consisting of CAS NCs prepared by spin coating without a high-temperature treatment. The CAS NC-based devices exhibited a diode-like current-voltage characteristic when coupled with an n-type CdS layer. In particular, the CuSbS2 NC devices exhibited photovoltaic responses under simulated sunlight, demonstrating its applicability for use in solution-processed solar cells.

  18. Synthesis of POP3HT/lead sulfide nanocomposites for hybrid solar cell

    NASA Astrophysics Data System (ADS)

    Zhou, Miaoxin

    2007-12-01

    The recent discovery of high efficiency multiexciton generation in lead sulfide (PbS) and lead selenide (PbSe) nanocrystals makes them promising materials for high efficiency solar cells. One complication of extracting charges from the nanocrystals is the insulating ligands capping their surfaces. In this dissertation, we have successfully developed and characterized a phosphonate functionalized poly-3-hexylthiophene (POP3HT-50) and used it in the direct synthesis of PbS nanocrystals without the aid of extraneous ligands. These POP3HT/PbS nanocomposites were characterized by HR-TEM, TM-AFM, 1H NMR and absorption spectroscopy. The nanocomposites were also incorporated into solar cell devices and tested under AM 1.5G conditions. Devices made of POP3HT-50/PbS nanocomposites show an order of magnitude improvement in photocurrent and power conversion efficiency (eta) when compared to that reported for a P3HT/PbS device (eta = 0.011% vs. 0.001%). The improved photocurrent is consistent with improved contact between PbS nanocrystals and POP3HT-50, presumably leading to more efficient charge transfer. However, the overall efficiencies of such devices were still very low suggesting that further modification was needed. Future research could be focused on developing functional conductive polymer with lower ionization potential (Ip) for proper band alignment with these infrared nanocrystals, and on developing elongated nanocrystals with proper aspect ratio to reduce the rate of Auger recombination (decay process of multiexciton state).

  19. Structural, optical and impurity-absorption properties of CdS thin films deposited by a chemical bath using four cadmium sources

    NASA Astrophysics Data System (ADS)

    Wang, Xian; Han, Anjun; Huang, Yongliang; Liu, Xiaohui; Liu, Zhengxin

    2017-07-01

    This study examines the effects of four cadmium sources on the properties of cadmium sulfide (CdS) thin films prepared using chemical bath methods. The reaction solutions used cadmium acetate, cadmium sulfate, cadmium iodide and cadmium chloride as cadmium sources. The surface morphology, crystal structure, optical properties and impurities absorption of CdS films were analyzed. The CdS films deposited with different Cd sources showed similar crystalline structures and surface morphologies. In addition, the Cd film band gaps differed unobviously. Measurements made with Fourier transform infrared spectrum showed that CN bonds were the main impurities absorbed in the CdS films. After the CdS films had been annealed at 120 °C in air, the CN peak intensity for cadmium acetate, cadmium sulfate and cadmium chloride decreased while the CN peak intensity for cadmium iodide increased. We found that the performance of a copper indium gallium selenide (CIGS) solar cell was influenced by the Cd sources; this was especially true for the fill factor (FF). Higher values of CN bonds absorption yielded lower values of FF and conversion efficiency of CIGS solar cells. Among the four tested Cd sources, cadmium acetate and cadmium sulfate proved much more suitable as Cd sources for depositing CdS thin films.

  20. Processing of Copper Zinc Tin Sulfide Nanocrystal Dispersions for Thin Film Solar Cells

    NASA Astrophysics Data System (ADS)

    Williams, Bryce Arthur

    A scalable and inexpensive renewable energy source is needed to meet the expected increase in electricity demand throughout the developed and developing world in the next 15 years without contributing further to global warming through CO2 emissions. Photovoltaics may meet this need but current technologies are less than ideal requiring complex manufacturing processes and/or use of toxic, rare-earth materials. Copper zinc tin sulfide (Cu 2ZnSnS4, CZTS) solar cells offer a true "green" alternative based upon non-toxic and abundant elements. Solution-based processes utilizing CZTS nanocrystal dispersions followed by high temperature annealing have received significant research attention due to their compatibility with traditional roll-to-roll coating processes. In this work, CZTS nanocrystal (5-35 nm diameters) dispersions were utilized as a production pathway to form solar absorber layers. Aerosol-based coating methods (aerosol jet printing and ultrasonic spray coating) were optimized for formation of dense, crack-free CZTS nanocrystal coatings. The primary variables underlying determination of coating morphology within the aerosol-coating parameter space were investigated. It was found that the liquid content of the aerosol droplets at the time of substrate impingement play a critical role. Evaporation of the liquid from the aerosol droplets during coating was altered through changes to coating parameters as well as to the CZTS nanocrystal dispersions. In addition, factors influencing conversion of CZTS nanocrystal coatings into dense, large-grained polycrystalline films suitable for solar cell development during thermal annealing were studied. The roles nanocrystal size, carbon content, sodium uptake, and sulfur pressure were found to have pivotal roles in film microstructure evolution. The effects of these parameters on film morphology, grain growth rates, and chemical makeup were analyzed from electron microscopy images as well as compositional analysis

  1. Performance optimization of solar cells based on colloidal lead sulfide nanocrystals

    SciTech Connect

    Ulfa, Maria

    2014-02-24

    Colloidal semiconducting quantum dot nanocrystals (NCs) have attracted extensive interest as active building-block for low-cost solution-processed photovoltaic due to their size tunable absorption from the visible to near IR. Among various nanocrystal composition, lead sulfide (PbS), having a bulk bandgap of 0.41 eV, are particularly attractive for photovoltaic applications due to their excellent photosensitivity in the near IR. Starting from colloidal synthesis, in this project functional solar cells are fabricated and characterized based on the nearly monodispersed colloidal PbS nanocrystals that we synthesized. These NC-solar cells are fabricated under a “depleted heterojunction” device architecture containing a planar “tipe II” heretojunction formed by a layer of electron-transporting TiO{sub 2} and a layer of PbS NCs. Relevant structural, optical, and electrical characterizations are performed on NCs and their devices. To understand the operational mechanism of these NC-based solar cells, various material and device aspects are investigated in this work aiming for optimized photovoltaic performance. These aspects include the effect of: (1) NC dimensions (and thus their band gaps); (2) passivation of surface traps through post-synthesis treatments; (3) NC surface ligand-exchange; and (4) interfacial modifications at the heterojunction. The most optimized photovoltaic performance is found after combining the surface trap passivation strategy by halides, ligand-exchange by 3-mercaptopropionic acids, and interfacial TiCl4 treatment, leading to a peak open-circuit voltage of 0.53 V, a short-circuit current density of 14.03 mAcm{sup −2}, and a power conversion efficiency of 3.25%.

  2. Synthesis and structural characterization of magnetic cadmium sulfide-cobalt ferrite nanocomposite, and study of its activity for dyes degradation under ultrasound

    NASA Astrophysics Data System (ADS)

    Farhadi, Saeed; Siadatnasab, Firouzeh

    2016-11-01

    Cadmium sulfide-cobalt ferrite (CdS/CFO) nanocomposite was easily synthesized by one-step hydrothermal decomposition of cadmium diethyldithiocarbamate complex on the CoFe2O4 nanoparticles at 200 °C. Spectroscopic techniques of powder X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), UV-visible spectroscopy, field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), Brunauer-Emmett-Teller (BET), and magnetic measurements were applied for characterizing the structure and morphology of the product. The results of FT-IR, XRD and EDX indicated that the CdS/CFO was highly pure. SEM and TEM results revealed that the CdS/CFO nanocomposite was formed from nearly uniform and sphere-like nanoparticles with the size of approximately 20 nm. The UV-vis absorption spectrum of the CdS/CFO nanocomposite showed the band gap of 2.21 eV, which made it suitable for sono-/photo catalytic purposes. By using the obtained CdS/CFO nanocomposite, an ultrasound-assisted advanced oxidation process (AOP) has been developed for catalytic degradation of methylene blue (MB), Rhodamine B (RhB), and methyl orange (MO)) in the presence of H2O2 as a green oxidant. CdS/CFO nanocomposite exhibited excellent sonocatalytic activity, so that, dyes were completely degraded in less than 10 min. The influences of crucial factors such as the H2O2 amount and catalyst dosage on the degradation efficiency were evaluated. The as-prepared CdS/CFO nanocomposite exhibited higher catalytic activity than pure CdS nanoparticles. Moreover, the magnetic property of CoFe2O4 made the nanocomposite recyclable.

  3. The risk to the United Kingdom population of zinc cadmium sulfide dispersion by the Ministry of Defence during the "cold war"

    PubMed Central

    Elliott, P; Phillips, C; Clayton, B; Lachmann, P

    2002-01-01

    Objectives: To estimate exposures to cadmium (Cd) received by the United Kingdom population as a result of the dispersion of zinc Cd sulfide (ZnCdS) by the Ministry of Defence between 1953 and 1964, as a simulator of biological warfare agents. Methods: A retrospective risk assessment study was carried out on the United Kingdom population during the period 1953–64. This determined land and air dispersion of ZnCdS over most of the United Kingdom, inhalation exposure of the United Kingdom population, soil contamination, and risks to personnel operating equipment that dispersed ZnCdS. Results: About 4600 kg ZnCdS were dispersed from aircraft and ships, at times when the prevailing winds would allow large areas of the country to be covered. Cadmium released from 44 long range trials for which data are available, and extrapolated to a total of 76 trials to allow for trials with incomplete information, is about 1.2% of the estimated total release of Cd into the atmosphere over the same period. "Worst case" estimates are 10 µg Cd inhaled over 8 years, equivalent to Cd inhaled in an urban environment in 12–100 days, or from smoking 100 cigarettes. A further 250 kg ZnCdS was dispersed from the land based sites, but significant soil contamination occurred only in limited areas, which were and have remained uninhabited. Of the four personnel involved in the dispersion procedures (who were probably exposed to much higher concentrations of Cd than people on the ground), none are suspected of having related illnesses. Conclusion: Exposure to Cd from dissemination of ZnCdS during the "cold war" should not have resulted in adverse health effects in the United Kingdom population. PMID:11836463

  4. The risk to the United Kingdom population of zinc cadmium sulfide dispersion by the Ministry of Defence during the "cold war".

    PubMed

    Elliott, P J; Phillips, C J C; Clayton, B; Lachmann, P J

    2002-01-01

    To estimate exposures to cadmium (Cd) received by the United Kingdom population as a result of the dispersion of zinc Cd sulfide (ZnCdS) by the Ministry of Defence between 1953 and 1964, as a simulator of biological warfare agents. A retrospective risk assessment study was carried out on the United Kingdom population during the period 1953-64. This determined land and air dispersion of ZnCdS over most of the United Kingdom, inhalation exposure of the United Kingdom population, soil contamination, and risks to personnel operating equipment that dispersed ZnCdS. About 4600 kg ZnCdS were dispersed from aircraft and ships, at times when the prevailing winds would allow large areas of the country to be covered. Cadmium released from 44 long range trials for which data are available, and extrapolated to a total of 76 trials to allow for trials with incomplete information, is about 1.2% of the estimated total release of Cd into the atmosphere over the same period. "Worst case" estimates are 10 microg Cd inhaled over 8 years, equivalent to Cd inhaled in an urban environment in 12100 days, or from smoking 100 cigarettes. A further 250 kg ZnCdS was dispersed from the land based sites, but significant soil contamination occurred only in limited areas, which were and have remained uninhabited. Of the four personnel involved in the dispersion procedures (who were probably exposed to much higher concentrations of Cd than people on the ground), none are suspected of having related illnesses. Exposure to Cd from dissemination of ZnCdS during the "cold war" should not have resulted in adverse health effects in the United Kingdom population.

  5. Enhanced photocatalytic activity of cadmium-doped Bi2WO6 nanoparticles under simulated solar light

    NASA Astrophysics Data System (ADS)

    Song, Xu Chun; Li, Wen Ting; Huang, Wan Zhen; Zhou, Huan; Yin, Hao Yong; Zheng, Yi Fan

    2015-03-01

    Novel cadmium-doped Bi2WO6 nanoparticles with different Cd contents have been synthesized by a one-step route using ethylene glycol and water as solvents at 180 °C for 12 h. The as-synthesized samples were characterized in detailed by SEM, XRD, EDS, HRTEM, UV-Vis DRS, BET techniques, and so on. The results shown that with the increase of the Cd2+ addition, the crystal structure, lattice space, and absorption edge were not significantly changed and the calculated band gap value was 2.58 eV. However, the flower-like Bi2WO6 sphere was gradually destroyed. Simultaneously, the surface area and photocurrent responses of the catalysts were greatly increased. Photocatalytic activity of the Cd-doped Bi2WO6 samples was determined by monitoring the change of RhB concentration under simulated solar light. The results revealed that cadmium doping greatly improved the photocatalytic efficiency of Bi2WO6. The Bi2WO6 sample with R Cd = 0.05 displayed the highest photocatalytic activity, and the degradation rate is about two times greater than pure Bi2WO6. Moreover, the Cd-Bi2WO6 photocatalyst remained stable even after five consecutive cycles. A possible mechanism of photocatalytic activity enhancement on basis of the experimental results was proposed.

  6. Flower-like nickel cobalt sulfide microspheres modified with nickel sulfide as Pt-free counter electrode for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Huo, Jinghao; Wu, Jihuai; Zheng, Min; Tu, Yongguang; Lan, Zhang

    2016-02-01

    The nickel cobalt sulfide/nickel sulfide (NiCo2S4/NiS) microspheres which exhibit flower-like morphologies are synthesized by a two-step hydrothermal method. Then the NiCo2S4/NiS microspheres are deposited on a fluorine doped SnO2 substrate by spin-casting the isopropyl alcohol solution of as-prepared microspheres. The cyclic voltammetry, electrochemical impedance spectroscopy and Tafel tests are employed to measure the electrochemical performance of NiCo2S4/NiS counter electrode. The NiCo2S4 and NiS all are used to improve the conductivity and electrocatalytic ability of the films, and the NiS can also increase the specific surface area of microspheres. The dye-sensitized solar cells (DSSCs) with the NiCo2S4/NiS counter electrode exhibite a power conversion efficiency of 8.8%, which is higher than that of DSSC with Pt counter electrode (8.1%) under the light intensity of 100 mW cm-2 (AM 1.5 G).

  7. Different behavior of Staphylococcus epidermidis in intracellular biosynthesis of silver and cadmium sulfide nanoparticles: more stability and lower toxicity of extracted nanoparticles.

    PubMed

    Rezvani Amin, Zohreh; Khashyarmanesh, Zahra; Fazly Bazzaz, Bibi Sedigheh

    2016-09-01

    Chemical reagents that are used for synthesis of nanoparticles are often toxic, while biological reagents are safer and cost-effective. Here, the behavior of Staphylococcus epidermidis (ATCC 12228) was evaluated for biosynthesis of silver nanoparticles (Ag-NPs) and cadmium sulfide nanoparticles (CdS-NPs) using TEM images intra- and extracellularly. The bacteria only biosynthesized the nanoparticles intracellularly and distributed Ag-NPs throughout the cytoplasm and on outside surface of cell walls, while CdS-NPs only formed in cytoplasm near the cell wall. A new method for purification of the nanoparticles was used. TEM images of pure CdS-NPs confirmed biosynthesis of agglomerated nanoparticles. Biosynthetic Ag-NPs were more stable against bright light and aggregation reaction than synthetic Ag-NPs (prepared chemically) also biosynthetic Ag-NPs displayed lower toxicity in in vitro assays. CdS-NPs indicated no toxicity in in vitro assays. Biosynthetic nanoparticles as product of the detoxification pathway may be safer and more stable for biosensors.

  8. A selective fluorescence probe for mercury ion based on the fluorescence quenching of terbium(III)-doped cadmium sulfide composite nanoparticles.

    PubMed

    Fu, Jie; Wang, Lun; Chen, Hongqi; Bo, Ling; Zhou, Cailing; Chen, Jingguo

    2010-10-15

    A fluorescent probe for mercury(II) ions, based on the quenching of fluorescence of terbium(III) ions doped in CdS nanoparticles, has been developed. The terbium(III)-doped cadmium sulfide composite nanoparticles were successfully synthesized through a straightforward one-pot process, with the biomolecule glutathione (GSH) as a capping ligand. In addition, the terbium(III) ions were observed an enhancement of emission intensity, owing to fluorescence energy transfer from the excited CdS particles to the emitting terbium(III). Because of a specific interaction, the fluorescence intensity of terbium(III)-doped CdS particles is obviously reduced in the presence of mercury(II) ions. The fluorescence quenching phenomenon of terbium(III) can be attributed to the fact that the energy transfer system was destroyed by combining with mercury(II). Under the optimal conditions, the fluorescent intensity of terbium(III) ions at 491nm decreased linearly with the concentration of mercury(II) ions ranging from 4.5nmolL(-1) to 550nmolL(-1). The limit of detection for mercury(II) was 0.1nmolL(-1). This method is simple, practical, relatively free of interference from coexisting substances and can be successfully applied to the determination of mercury(II) ions in real water samples. In addition, the probable mechanism of reaction between terbium(III)-doped CdS composite nanoparticles and mercury(II) was also discussed.

  9. Luminescence and generation of laser radiation in zinc selenide and cadmium sulfide single crystals exposed to high-voltage subnanosecond pulses

    SciTech Connect

    Mesyats, G. A.; Nasibov, A. S. Shpak, V. G.; Shunailov, S. A.; Yalandin, M. I.

    2008-06-15

    The action of high-voltage subnanosecond pulses on A{sup II}B{sup VI} semiconductor compounds is studied. A negative pulse with a duration of up to 500 ps is applied to electrodes of a special shape. The pulse amplitude can be varied from 20 to 250 kV. Plane-parallel plates with a thickness of 1-2 mm made of bulk zinc selenide or cadmium sulfide single crystals are placed between the electrodes. Experiments are carried out in air without submerging single crystal plates in a liquid dielectric medium. As soon as a voltage pulse is applied, diverging discharges propagate from sharp edges of the negative electrode along electric field lines. With increasing voltage, generation of laser radiation is observed in the bulk of the semiconductor, displaying all its characteristic features, such as a sharp increase in the radiation power, narrowing the spectrum, and the radiation directionality. For zinc selenide at room temperature, the radiation characteristics are as follows: the wavelength is 480 nm, the radiation divergence is about 3{sup o}, and the peak pulse power is 600 W.

  10. Thermo-optical characterization of cadmium selenide/zinc sulfide (CdSe/ZnS) quantum dots embedded in biocompatible materials.

    PubMed

    Pilla, Viviane; Alves, Leandro P; Iwazaki, Adalberto N; Andrade, Acácio A; Antunes, Andrea; Munin, Egberto

    2013-09-01

    Cadmium selenide/zinc sulfide (CdSe/ZnS) core-shell quantum dots (QDs) embedded in biocompatible materials were thermally and optically characterized with a thermal lens (TL) technique. Transient TL measurements were performed with a mode-mismatched, dual-beam (excitation and probe) configuration. A thermo-optical study of the CdSe/ZnS QDs was performed for different core diameters (3.5, 4.0, 5.2, and 6.6 nm) in aqueous solution and synthetic saliva, and three different core diameters (2.4, 2.9, and 4.1 nm) embedded in restorative dental resin (0.025% by mass). The thermal diffusivity results are characteristic of the biocompatible matrices. The radiative quantum efficiencies for aqueous solution and biofluid materials are dependent on the core size of the CdSe/ZnS core-shell QDs. The results obtained from the fluorescence spectral measurements for the biocompatible materials support the TL results.

  11. Solar light-driven photocatalytic hydrogen evolution over ZnIn2S4 loaded with transition-metal sulfides

    PubMed Central

    2011-01-01

    A series of Pt-loaded MS/ZnIn2S4 (MS = transition-metal sulfide: Ag2S, SnS, CoS, CuS, NiS, and MnS) photocatalysts was investigated to show various photocatalytic activities depending on different transition-metal sulfides. Thereinto, CoS, NiS, or MnS-loading lowered down the photocatalytic activity of ZnIn2S4, while Ag2S, SnS, or CuS loading enhanced the photocatalytic activity. After loading 1.0 wt.% CuS together with 1.0 wt.% Pt on ZnIn2S4, the activity for H2 evolution was increased by up to 1.6 times, compared to the ZnIn2S4 only loaded with 1.0 wt.% Pt. Here, transition-metal sulfides such as CuS, together with Pt, acted as the dual co-catalysts for the improved photocatalytic performance. This study indicated that the application of transition-metal sulfides as effective co-catalysts opened up a new way to design and prepare high-efficiency and low-cost photocatalysts for solar-hydrogen conversion. PMID:21711804

  12. Thin film cadmium telluride, zinc telluride, and mercury zinc telluride solar cells

    SciTech Connect

    Chu, T.L. )

    1992-04-01

    This report describes research to demonstrate (1) thin film cadmium telluride solar cells with a quantum efficiency of 75% or higher at 0. 44 {mu}m and a photovoltaic efficiency of 11.5% or greater, and (2) thin film zinc telluride and mercury zinc telluride solar cells with a transparency to sub-band-gap radiation of 65% and a photovoltaic conversion efficiency of 5% and 8%, respectively. Work was directed at (1) depositing transparent conducting semiconductor films by solution growth and metal-organic chemical vapor deposition (MOCVD) technique, (2) depositing CdTe films by close-spaced sublimation (CSS) and MOCVD techniques, (3) preparing and evaluating thin film CdTe solar cells, and (4) preparing and characterizing thin film ZnTe, CD{sub 1-x}Zn{sub 1-x}Te, and Hg{sub 1-x}Zn{sub x}Te solar cells. The deposition of CdS films from aqueous solutions was investigated in detail, and their crystallographic, optical, and electrical properties were characterized. CdTe films were deposited from DMCd and DIPTe at 400{degrees}C using TEGa and AsH{sub 3} as dopants. CdTe films deposited by CSS had significantly better microstructures than those deposited by MOCVD. Deep energy states in CdTe films deposited by CSS and MOCVD were investigated. Thin films of ZnTe, Cd{sub 1- x}Zn{sub x}Te, and Hg{sub 1-x}Zn{sub x}Te were deposited by MOCVD, and their crystallographic, optical, and electrical properties were characterized. 67 refs.

  13. Zelda and company - Petrogenesis of sulfide-rich Fremdlinge and constraints on solar nebula processes

    NASA Technical Reports Server (NTRS)

    Armstrong, John T.; Hutcheon, Ian D.; Wasserburg, G. J.

    1987-01-01

    A detailed petrographic and chemical study of Zelda (a gigantic sulfide-rich Fremdling from the Allende Ca-rich inclusion, CAI, Egg 6) and its contact with the host was conducted using analytical SEM and electron-microprobe techniques, and the results were compared with those obtained on other sulfide-rich and oxide-rich Fremdlinge. Strong evidence is presented that Zelda, a type-example of sulfide-rich Fremdlinge, has been formed from a preexisting Ur-Fremdling, similar by composition to Willy, by closed-system sulfidization of magnetite and metal. At least two different sulfidization mechanisms appear to have occurred in altering Fremdlinge: one producing compositionally homogeneous equigranular objects such as Zelda, the other producing compositionally and texturally heterogeneous objects.

  14. Zelda and company - Petrogenesis of sulfide-rich Fremdlinge and constraints on solar nebula processes

    NASA Technical Reports Server (NTRS)

    Armstrong, John T.; Hutcheon, Ian D.; Wasserburg, G. J.

    1987-01-01

    A detailed petrographic and chemical study of Zelda (a gigantic sulfide-rich Fremdling from the Allende Ca-rich inclusion, CAI, Egg 6) and its contact with the host was conducted using analytical SEM and electron-microprobe techniques, and the results were compared with those obtained on other sulfide-rich and oxide-rich Fremdlinge. Strong evidence is presented that Zelda, a type-example of sulfide-rich Fremdlinge, has been formed from a preexisting Ur-Fremdling, similar by composition to Willy, by closed-system sulfidization of magnetite and metal. At least two different sulfidization mechanisms appear to have occurred in altering Fremdlinge: one producing compositionally homogeneous equigranular objects such as Zelda, the other producing compositionally and texturally heterogeneous objects.

  15. Cadmium sulfide/copper sulfide heterojunction cell research by sputter deposition. Quarterly technical progress report, March 1, 1981-June 30, 1981

    SciTech Connect

    Thornton, J.A.; Anderson, W.W.; Meakin, J.D.

    1981-08-01

    A second series of hybrid cells with sputter-deposited Cu/sub 2/S layers has been fabricated. An efficiency of about 4 3/4%, without antireflection coating, was achieved for one of the cells. This result approaches the 5 3/4% which was achieved in the first set (different Cu/sub 2/S deposition conditions) and confirms the viability of the sputtering process for this application. Significant progress has been made in fabricating all-sputtered cells with CdS layers deposited by planar magnetron reactive sputtering. Efficiencies of approximately 3%, without antireflection coatings, have been achieved in the as-deposited state for seven cells. Individual cells have yielded a J/sub sc/ of 12 mA/cm/sup 2/, a V/sub oc/ of 0.53V, and a fill factor of 0.72. Taken together these parameters would yield an efficiency of 4 1/2%. A strong coupling is found between the properties of the Cu/sub 2/S and CdS layers. However, the conditions which maximize J/sub sc/, V/sub oc/ and the fill factor do not appear to be mutually exclusive. Reflectance measurements indicate that 30% or more of the incident radiation is being reflected from the front surface of the cells over the wavelength range of the solar spectrum. Thus optimization of the cell parameters with a suitable antireflection coating should yield cell efficiencies of about 6%. Characterization of the junctions formed in the all-sputtered cells under near-optimum deposition conditions indicates that they have remarkable properties in their as-deposited state, being very similar to high performance conventional cells after heat treatment. Junction ideality factors are about unity in the light, with J/sub 0/ values of about 2 x 10/sup -8/ mA/cm/sup 2/. Interface recombination velocities are as low as a few times 10/sup 5/ cm/sec. CdS depletion layer widths are about 2000 nm in the dark and collapse to about 200 nm under illumination.

  16. Quantum dot-sensitized solar cells based on directly adsorbed zinc copper indium sulfide colloids.

    PubMed

    Guijarro, Néstor; Guillén, Elena; Lana-Villarreal, Teresa; Gómez, Roberto

    2014-05-21

    Heavy metal-based quantum dots (QDs) have been demonstrated to behave as efficient sensitizers in QD-sensitized solar cells (QDSSCs), as attested by the countless studies and encouraging efficiencies reported so far. However, their intrinsic toxicity has arisen as a major issue for the prospects of commercialization. Here, we examine the potential of environmentally friendly zinc copper indium sulfide (ZCIS) QDs for the fabrication of liquid-junction QDSSCs by means of photoelectrochemical measurements. A straightforward approach to directly adsorb ZCIS QDs on TiO2 from a colloidal dispersion is presented. Incident photon-to-current efficiency (IPCE) spectra of sensitized photoanodes show a marked dependence on adsorption time, with longer times leading to poorer performances. Cyclic voltammograms point to a blockage of the channels of the mesoporous TiO2 film by the agglomeration of QDs as the main reason for the decrease in efficiency. Photoanodes were also subjected to the ZnS treatment. Its effects on electron recombination with the electrolyte are analyzed through electrochemical impedance spectroscopy and photopotential measurements. The corresponding results bring out the role of the ZnS coating as a barrier layer in preventing electron leakage toward the electrolyte, as argued in other QD-sensitized systems. The beneficial effect of the ZnS coating is ultimately reflected in the power conversion efficiency of complete devices, reaching values of 2%. In a more general vein, through these findings, we aim to call the attention to the potentiality of this quaternary alloy, virtually unexplored as a light harvester for sensitized devices.

  17. Lead Sulfide Cathode for Quantum Dot Solar Cells: Electrosynthesis and Characterization

    NASA Astrophysics Data System (ADS)

    Van Le, Nghiem; Nguyen, Hoang Thai; Le, Hai Viet; Nguyen, Thoa Thi Phuong

    2017-01-01

    Deposition of lead sulfide (PbS) nanocrystalline thin films onto conducting fluorine-doped tin oxide (FTO) glass has been performed by cyclic voltammetry (CV) in 1.5 mM solution of lead nitrate and sodium thiosulfate at 100 mV s-1 scan rate in the potential range of -1.0 V to 0.0 V versus saturated calomel electrode. X-ray diffraction analysis and scanning electron microscopy revealed formation of cubic PbS crystals with size of 100 nm to 150 nm after 50 cycles. High electrocatalytic activity of the synthesized PbS film for the S2-/S n 2- redox couple, used as a mediator for quantum dot solar cells (QDSCs), was demonstrated by electrochemical impedance spectroscopy and CV measurements. The prepared PbS/FTO was used as a counterelectrode to fabricate PbS-QDSCs with a photoanode consisting of CdS/CdSe quantum dots adsorbed on mesoporous TiO2 film and a polysulfide solution electrolyte. The performance of the PbS-QDSC was compared with a QDSC with a platinum counterelectrode (Pt-QDSC). It was found that, using the same fabrication conditions, the performance of the PbS-QDSC was better than that of the Pt-QDSC. At 1 sun (100 mW cm-2) simulated light, average energy conversion efficiency of 2.14%, short-circuit current of 9.22 mA cm-2, open-circuit potential of 0.50 V, and fill factor of 0.47 were achieved by the fabricated PbS-QDSC.

  18. Synthesis and Electrophoretic Concentration of Cadmium Sulfide Nanoparticles in Reverse Microemulsions of Tergitol NP-4 in n-Decane.

    PubMed

    Kolodin, Aleksei N; Tatarchuk, Vladimir V; Bulavchenko, Alexander I; Poleeva, Evgeniia V

    2017-08-22

    The kinetics of thiourea synthesis of CdS nanoparticles (NPs) in reverse microemulsions of Tergitol Np-4/n-decane was studied in the temperature range of 313-333 K by spectrophotometry, photon-correlation spectroscopy, and transmission electron microscopy. The formation of NPs is described by the kinetic model, including two consecutive steps: homogeneous nucleation in a solution as the first step and the autocatalytic growth of NPs due to heterogeneous reaction on a continuously increasing surface as the second step. Effective rate constants of the steps (k1 = 1.52 × 10(-2)-1.75 × 10(-3) s(-1) and k2 = 4.9 × 10(-1)-5.1 × 10(-2) M(-1) s(-1)) and effective activation energies (Ea1 = 156 and Ea2 = 149 kJ/mol) were estimated in the pseudo-first-order reaction with respect to cadmium (cCd = 0.9 mM, cThio = 9 mM). The obtained constants were used to calculate the dependence of nanoparticle diameter on the synthesis time (d(3) ∼ t). The calculated values correlate well with experimental data of photon-correlation spectroscopy and transmission electron microscopy.

  19. Characterization and evaluation of cadmium indate photocatalysts for solar hydrogen conversion

    NASA Astrophysics Data System (ADS)

    Thornton, Jason M.

    Alternative energy sources are needed to respond to the continued increase in the global energy needs and a potential decrease in the future supplies of fossil fuels. Solar hydrogen conversion in which sunlight is harnessed to split water into H2 fuel and O2 is a promising source of energy because it is renewable and produces no CO2. A number of semiconducting oxide materials have shown promise for overall water splitting for the generation of hydrogen over the years. In this work we focus on the synthesis and analysis of undoped and C-doped cadmium indate (CdIn2O 4) thin films and nanoparticle powders, and their evaluation for hydrogen evolution via water splitting. The catalyst was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis, scanning electron microscopy (SEM), and BET surface adsorption measurements. Spray and sol-gel pyrolysis methods were used for the synthesis of the materials. Doping C into CdIn 2O4 leads to enhancement in light absorption and the band gap was determined to be 2.3 eV in the nanoparticle powders. Carbon doping improves the photocurrent density by 33% and the H2 evolution rate by a factor of two. The performance of C-doped CdIn2O4 were optimized with respect to several synthetic parameters, including the In:Cd molar ratio and glucose concentration, calcination temperature, and the film thickness while the nanoparticles were additionally optimized to F127 concentration and platinum cocatalyst loading. Hydrogen generation activity was evaluated under UV-visible irradiation without the use of a sacrificial reagent and using bandpass filters the quantum efficiency was determined. Compared to platinized TiO2 in methanol C-CdIn2O4 showed a 4-fold increase in hydrogen production. The material was capable of hydrogen generation using visible light only and with good efficiency even at 510 nm. Using natural sunlight illumination, the material evolved hydrogen at a rate of 17 micromol h-1. These studies show

  20. Cadmium sulfide/graphitic carbon nitride heterostructure nanowire loading with a nickel hydroxide cocatalyst for highly efficient photocatalytic hydrogen production in water under visible light

    NASA Astrophysics Data System (ADS)

    Yan, Zhiping; Sun, Zijun; Liu, Xiang; Jia, Hongxing; Du, Pingwu

    2016-02-01

    Photocatalytic hydrogen production from water in a noble-metal-free system has attracted much attention in recent years. Herein we report on the use of core/shell cadmium sulfide/graphitic carbon nitride (CdS/g-C3N4) heterojunction nanorods modified by nickel hydroxide (Ni(OH)2) as a highly efficient photocatalyst for visible light-driven hydrogen production from water. Due to efficient separation of the photoexcited charge carriers in the CdS/g-C3N4 core/shell nanorods and the synergistic effect of Ni(OH)2, the optimal hydrogen evolution rate over Ni(OH)2-CdS/g-C3N4 is 115.18 μmol h-1 mg-1 under visible light irradiation (λ > 420 nm), which is ~26 times higher than the CdS/g-C3N4 nanorod composite without Ni(OH)2 and ~7 times better than the 0.5 wt% Pt-CdS/g-C3N4 nanorod composite. The apparent quantum efficiency is ~16.7% at an excitation of 450 nm. During photocatalysis, no degradation of Ni(OH)2 was observed based on the XPS data, indicating that it is a robust cocatalyst. Moreover, the present photocatalyst showed excellent photocatalytic stability for hydrogen production and the turnover number (TON) reached ~24 600 over 90 hours.Photocatalytic hydrogen production from water in a noble-metal-free system has attracted much attention in recent years. Herein we report on the use of core/shell cadmium sulfide/graphitic carbon nitride (CdS/g-C3N4) heterojunction nanorods modified by nickel hydroxide (Ni(OH)2) as a highly efficient photocatalyst for visible light-driven hydrogen production from water. Due to efficient separation of the photoexcited charge carriers in the CdS/g-C3N4 core/shell nanorods and the synergistic effect of Ni(OH)2, the optimal hydrogen evolution rate over Ni(OH)2-CdS/g-C3N4 is 115.18 μmol h-1 mg-1 under visible light irradiation (λ > 420 nm), which is ~26 times higher than the CdS/g-C3N4 nanorod composite without Ni(OH)2 and ~7 times better than the 0.5 wt% Pt-CdS/g-C3N4 nanorod composite. The apparent quantum efficiency is ~16.7% at an

  1. Effect of the Concentration on the X-ray Luminescence Efficiency of a Cadmium Selenide/Zinc Sulfide (CdSe/ZnS) Quantum Dot Nanoparticle Solution

    NASA Astrophysics Data System (ADS)

    Valais, I.; Michail, C.; Nikolopoulos, D.; Fountzoula, C.; Bakas, A.; Yannakopoulos, P.; Fountos, G.; Panayiotakis, G.; Kandarakis, I.

    2015-09-01

    In the current study preliminary results on the luminescence efficiency (LE) of toluene dissolved Cadmium Selenide/Zinc Sulfide (CdSe/ZnS, Sigma-Aldrich, Lumidot 694622) quantum dot samples (QDs) after exposure to X-rays of variable radiation flux are shown. The distinctive influence of the weight over volume (w/v) concentration of the samples in LE was investigated. The light emission of the QDs was additionally measured after UV irradiation. The distribution of the emitted light was symmetrical with a maximum at 590 nm. The w/v concentration of the QDs varied between 7.1×10-5 mg/mL to 28.4×10-5 mg/mL. The samples were handled in a cubic 12.5×12.5×45mm3 quartz cuvette. Each sample was excited under X-ray irradiation, in the energy range from 50 to 130 kVp using a BMI General Medical Merate tube with rotating Tungsten anode and inherent filtration equivalent to 2 mm Al. The X-ray LE, induced by the 28.4×10-5 mg/mL QDs found higher, however, the distinction was vague in the highly concentrated samples. The maximum efficiency was obtained at the 90 kVp for QDs with 21.3×10-5 mg/mL w/v concentration. In the high energy range (120-130 kVp) all concentration levels exhibited comparable X-ray induced LE. The luminescence properties of the investigated QDs appear promising for X-ray detection applications.

  2. Commercialization of thick film solar cell. Final technical report, 9/15/79-9/14/80

    SciTech Connect

    1980-01-01

    Films of cadmium sulfide and cadmium telluride have been produced by screen printing and sintering. Cadmium sulfide films ten microns thick had a resistivity in the 10 ohm-cm range. A technique was developed for forming a cadmium telluride layer on top of a cadmium sulfide layer. Process control and device preparation are areas requiring further study.

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

    SciTech Connect

    Gupta, Vinay; Upreti, Tanvi; Chand, Suresh

    2013-12-16

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

  4. Process for removing cadmium from scrap metal

    SciTech Connect

    Kronberg, J.W.

    1994-01-01

    A process for the recovery of a metal, in particular, cadmium contained in scrap, in a stable form. The process comprises the steps of mixing the cadmium-containing scrap with an ammonium carbonate solution, preferably at least a stoichiometric amount of ammonium carbonate, and/or free ammonia, and an oxidizing agent to form a first mixture so that the cadmium will react with the ammonium carbonate to form a water-soluble ammine complex; evaporating the first mixture so that ammine complex dissociates from the first mixture leaving carbonate ions to react with the cadmium and form a second mixture that includes cadmium carbonate; optionally adding water to the second mixture to form a third mixture; adjusting the pH of the third mixture to the acid range whereby the cadmium carbonate will dissolve; and adding at least a stoichiometric amount of sulfide, preferably in the form of hydrogen sulfide or an aqueous ammonium sulfide solution, to the third mixture to precipitate cadmium sulfide. This mixture of sulfide is then preferably digested by heating to facilitate precipitation of large particles of cadmium sulfide. The scrap may be divided by shredding or breaking up to exposure additional surface area. Finally, the precipitated cadmium sulfide can be mixed with glass formers and vitrified for permanent disposal.

  5. Process for removing cadmium from scrap metal

    DOEpatents

    Kronberg, James W.

    1995-01-01

    A process for the recovery of a metal, in particular, cadmium contained in scrap, in a stable form. The process comprises the steps of mixing the cadmium-containing scrap with an ammonium carbonate solution, preferably at least a stoichiometric amount of ammonium carbonate, and/or free ammonia, and an oxidizing agent to form a first mixture so that the cadmium will react with the ammonium carbonate to form a water-soluble ammine complex; evaporating the first mixture so that ammine complex dissociates from the first mixture leaving carbonate ions to react with the cadmium and form a second mixture that includes cadmium carbonate; optionally adding water to the second mixture to form a third mixture; adjusting the pH of the third mixture to the acid range whereby the cadmium carbonate will dissolve; and adding at least a stoichiometric amount of sulfide, preferably in the form of hydrogen sulfide or an aqueous ammonium sulfide solution, to the third mixture to precipitate cadmium sulfide. This mixture of sulfide is then preferably digested by heating to facilitate precipitation of large particles of cadmium sulfide. The scrap may be divided by shredding or breaking up to expose additional surface area. Finally, the precipitated cadmium sulfide can be mixed with glass formers and vitrified for permanent disposal.

  6. Process for removing cadmium from scrap metal

    DOEpatents

    Kronberg, J.W.

    1995-04-11

    A process is described for the recovery of a metal, in particular, cadmium contained in scrap, in a stable form. The process comprises the steps of mixing the cadmium-containing scrap with an ammonium carbonate solution, preferably at least a stoichiometric amount of ammonium carbonate, and/or free ammonia, and an oxidizing agent to form a first mixture so that the cadmium will react with the ammonium carbonate to form a water-soluble ammine complex; evaporating the first mixture so that ammine complex dissociates from the first mixture leaving carbonate ions to react with the cadmium and form a second mixture that includes cadmium carbonate; optionally adding water to the second mixture to form a third mixture; adjusting the pH of the third mixture to the acid range whereby the cadmium carbonate will dissolve; and adding at least a stoichiometric amount of sulfide, preferably in the form of hydrogen sulfide or an aqueous ammonium sulfide solution, to the third mixture to precipitate cadmium sulfide. This mixture of sulfide is then preferably digested by heating to facilitate precipitation of large particles of cadmium sulfide. The scrap may be divided by shredding or breaking up to expose additional surface area. Finally, the precipitated cadmium sulfide can be mixed with glass formers and vitrified for permanent disposal. 2 figures.

  7. Radiation resistance of thin-film solar cells for space photovoltaic power

    NASA Technical Reports Server (NTRS)

    Woodyard, James R.; Landis, Geoffrey A.

    1991-01-01

    Copper indium diselenide, cadmium telluride, and amorphous silicon alloy solar cells have achieved noteworthy performance and are currently being studied for space power applications. Cadmium sulfide cells had been the subject of much effort but are no longer considered for space applications. A review is presented of what is known about the radiation degradation of thin film solar cells in space. Experimental cadmium telluride and amorphous silicon alloy cells are reviewed. Damage mechanisms and radiation induced defect generation and passivation in the amorphous silicon alloy cell are discussed in detail due to the greater amount of experimental data available.

  8. Cadmium Disrupts the Balance between Hydrogen Peroxide and Superoxide Radical by Regulating Endogenous Hydrogen Sulfide in the Root Tip of Brassica rapa.

    PubMed

    Lv, Wenjing; Yang, Lifei; Xu, Cunfa; Shi, Zhiqi; Shao, Jinsong; Xian, Ming; Chen, Jian

    2017-01-01

    Cd (cadmium) stress always alters the homeostasis of ROS (reactive oxygen species) including H2O2 (hydrogen sulfide) and [Formula: see text] (superoxide radical), leading to the oxidative injury and growth inhibition in plants. In addition to triggering oxidative injury, ROS has been suggested as important regulators modulating root elongation. However, whether and how Cd stress induces the inhibition of root elongation by differentially regulating endogenous H2O2 and [Formula: see text], rather than by inducing oxidative injury, remains elusive. To address these gaps, histochemical, physiological, and biochemical approaches were applied to investigate the mechanism for Cd to fine-tune the balance between H2O2 and [Formula: see text] in the root tip of Brassica rapa. Treatment with Cd at 4 and 16 μM significantly inhibited root elongation, while only 16 μM but not 4 μM of Cd induced oxidative injury and cell death in root tip. Fluorescent and pharmaceutical tests suggested that H2O2 and [Formula: see text] played negative and positive roles, respectively, in the regulation of root elongation in the presence of Cd (4 μM) or not. Treatment with Cd at 4 μM led to the increase in H2O2 and the decrease in [Formula: see text] in root tip, which may be attributed to the up-regulation of Br_UPB1s and the down-regulation of their predicted targets (four peroxidase genes). Cd at 4 μM resulted in the increase in endogenous H2S in root tip by inducing the up-regulation of LCDs and DCDs. Treatment with H2S biosynthesis inhibitor or H2S scavenger significantly blocked Cd (4 μM)-induced increase in endogenous H2S level, coinciding with the recovery of root elongation, the altered balance between H2O2 and [Formula: see text], and the expression of Br_UPB1s and two peroxidase genes. Taken together, it can be proposed that endogenous H2S mediated the phytotoxicity of Cd at low concentration by regulating Br_UPB1s-modulated balance between H2O2 and [Formula: see text] in root

  9. Cadmium Disrupts the Balance between Hydrogen Peroxide and Superoxide Radical by Regulating Endogenous Hydrogen Sulfide in the Root Tip of Brassica rapa

    PubMed Central

    Lv, Wenjing; Yang, Lifei; Xu, Cunfa; Shi, Zhiqi; Shao, Jinsong; Xian, Ming; Chen, Jian

    2017-01-01

    Cd (cadmium) stress always alters the homeostasis of ROS (reactive oxygen species) including H2O2 (hydrogen sulfide) and O2•– (superoxide radical), leading to the oxidative injury and growth inhibition in plants. In addition to triggering oxidative injury, ROS has been suggested as important regulators modulating root elongation. However, whether and how Cd stress induces the inhibition of root elongation by differentially regulating endogenous H2O2 and O2•–, rather than by inducing oxidative injury, remains elusive. To address these gaps, histochemical, physiological, and biochemical approaches were applied to investigate the mechanism for Cd to fine-tune the balance between H2O2 and O2•– in the root tip of Brassica rapa. Treatment with Cd at 4 and 16 μM significantly inhibited root elongation, while only 16 μM but not 4 μM of Cd induced oxidative injury and cell death in root tip. Fluorescent and pharmaceutical tests suggested that H2O2 and O2•– played negative and positive roles, respectively, in the regulation of root elongation in the presence of Cd (4 μM) or not. Treatment with Cd at 4 μM led to the increase in H2O2 and the decrease in O2•– in root tip, which may be attributed to the up-regulation of Br_UPB1s and the down-regulation of their predicted targets (four peroxidase genes). Cd at 4 μM resulted in the increase in endogenous H2S in root tip by inducing the up-regulation of LCDs and DCDs. Treatment with H2S biosynthesis inhibitor or H2S scavenger significantly blocked Cd (4 μM)-induced increase in endogenous H2S level, coinciding with the recovery of root elongation, the altered balance between H2O2 and O2•–, and the expression of Br_UPB1s and two peroxidase genes. Taken together, it can be proposed that endogenous H2S mediated the phytotoxicity of Cd at low concentration by regulating Br_UPB1s-modulated balance between H2O2 and O2•– in root tip. Such findings shed new light on the regulatory role of endogenous H2S in

  10. Discovery of Hg-Cu-bearing metal-sulfide assemblages in a primitive H-3 chondrite: Towards a new insight in early solar system processes

    NASA Astrophysics Data System (ADS)

    Caillet Komorowski, Catherine; El Goresy, Ahmed; Miyahara, Masaaki; Boudouma, Omar; Ma, Chi

    2012-10-01

    We report here the discovery of a novel meteoritic paragenesis consisting of sub-micrometric HgS, Cu sulfides, and Hg metal, associated with polycrystalline fine-grained native Cu in opaque mineral aggregates heterogeneously distributed in the matrix of the H-3 Tieschitz unequilibrated ordinary chondrite (UOC). The systematic association of Hg with Cu in Tieschitz chondrite provides a unique opportunity to place robust constraints on the origin of these assemblages either by condensation and sulfidation in a local nebular reservoir of non-solar composition, followed by gentle and fast accretion, or by sublimation of Hg from the hot interior of the asteroid and recondensation in its cold outer regions. The sulfide phase relations support low temperature conditions (<300 °C), implying that subsequent to accretion indigenous hydrothermal processing, oxidation/sulfidation, transportation, or shock-induced thermal processing of the assemblage on the parent body earlier proposed are very unlikely and unrealistic. Origin of HgS by sublimation of Hg from the hotter asteroid interior and precipitation as cinnabar in the colder surface regions is discrepant with our findings and can be ruled out because cinnabar occurs only in Tieschitz matrix in alternating rhythmic intergrowth with Cu-sulfide. The sublimation scenario calls for co-evaporation of both the highly volatile Hg as HgS and Hg metal and the moderately volatile Cu both as Cu metal, or their sulfides and deposition as sulfides in alternating episodes. Our findings provide further ample evidence refuting the repeated claim of formation of native copper in chondritic metal by shock-induced impact melting. Cold accretion is the only reasonable possibility to preserve the delicate accretionary intergrowth textures, the polycrystallinity of FeNi-metal, native Cu, Hg-Cu-sulfides and native Hg globules and the high Hg concentration retained in this meteorite. Our findings strongly suggest that Tieschitz resided near the

  11. Space-based solar power conversion and delivery systems study. Volume 4: Energy conversion systems studies

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Solar cells and optical configurations for the SSPS were examined. In this task, three specific solar cell materials were examined: single crystal silicon, single crystal gallium arsenide, and polycrystalline cadmium sulfide. The comparison of the three different cells on the basis of a subsystem parametric cost per kW of SSPS-generated power at the terrestrial utility interface showed that gallium arsenide was the most promising solar cell material at high concentration ratios. The most promising solar cell material with no concentration, was dependent upon the particular combination of parameters representing cost, mass and performance that were chosen to represent each cell in this deterministic comparative analysis. The potential for mass production, based on the projections of the present state-of-the-art would tend to favor cadmium sulfide in lieu of single crystal silicon or gallium arsenide solar cells.

  12. A metal sulfide photocatalyst composed of ubiquitous elements for solar hydrogen production.

    PubMed

    Shiga, Y; Umezawa, N; Srinivasan, N; Koyasu, S; Sakai, E; Miyauchi, M

    2016-06-14

    A visible-light-sensitive tin sulfide photocatalyst was designed based on a ubiquitous element strategy and density functional theory (DFT) calculations. Computational analysis suggested that tin monosulfide (SnS) would be more efficient than SnS2 as a photocathode for hydrogen production because of the low ionization potential and weak ionic character of SnS. To test this experimentally, nanoparticles of SnS were loaded onto a mesoporous electrode using a wet chemical method, and the bandgap of the synthesized SnS quantum dots was found to be tunable by adjusting the number of successive ionic layer adsorption and reaction (SILAR) cycles, which controls the magnitude of the quantum confinement effect. Efficient hydrogen production was achieved when the bandgap of SnS was wider than that of the bulk form.

  13. The 100 kW space station. [regenerative fuel cells and nickel hydrogen and nickel cadmium batteries for solar arrays

    NASA Technical Reports Server (NTRS)

    Mckhann, G.

    1977-01-01

    Solar array power systems for the space construction base are discussed. Nickel cadmium and nickel hydrogen batteries are equally attractive relative to regenerative fuel cell systems at 5 years life. Further evaluation of energy storage system life (low orbit conditions) is required. Shuttle and solid polymer electrolyte fuel cell technology appears adequate; large units (approximately four times shuttle) are most appropriate and should be studied for a 100 KWe SCB system. A conservative NiH2 battery DOD (18.6%) was elected due to lack of test data and offers considerable improvement potential. Multiorbit load averaging and reserve capacity requirements limit nominal DOD to 30% to 50% maximum, independent of life considerations.

  14. The 100 kW space station. [regenerative fuel cells and nickel hydrogen and nickel cadmium batteries for solar arrays

    NASA Technical Reports Server (NTRS)

    Mckhann, G.

    1977-01-01

    Solar array power systems for the space construction base are discussed. Nickel cadmium and nickel hydrogen batteries are equally attractive relative to regenerative fuel cell systems at 5 years life. Further evaluation of energy storage system life (low orbit conditions) is required. Shuttle and solid polymer electrolyte fuel cell technology appears adequate; large units (approximately four times shuttle) are most appropriate and should be studied for a 100 KWe SCB system. A conservative NiH2 battery DOD (18.6%) was elected due to lack of test data and offers considerable improvement potential. Multiorbit load averaging and reserve capacity requirements limit nominal DOD to 30% to 50% maximum, independent of life considerations.

  15. Tin doping in spray pyrolysed indium sulfide thin films for solar cell applications

    SciTech Connect

    Mathew, Meril; Gopinath, Manju; Kartha, C. Sudha; P.Vijayakumar, K.; Kashiwaba, Y.; Abe, T.

    2010-06-15

    This paper presents studies carried out on tin-doped indium sulfide films prepared using Chemical Spray Pyrolysis (CSP) technique. Effect of both in-situ and ex-situ doping were analyzed. Ex-situ doping was done by thermal diffusion, which was realized by annealing Sn/In{sub 2}S{sub 3} bilayer films. In-situ doping was accomplished by introducing Sn into the spray solution by using SnCl{sub 4}.5H{sub 2}O. Interestingly, it was noted that by ex-situ doping, conductivity of the sample enhanced considerably without affecting any of the physical properties such as crystallinity or band gap. Analysis also showed that higher percentage of doping resulted in samples with low crystallinity and negative photosensitivity. In-situ doping resulted in amorphous films. In contrast to ex-situ doping, 'in- situ doping' resulted in widening of optical band gap through oxygen incorporation; also it gave highly photosensitive films. (author)

  16. Efficient Nickel Sulfide and Graphene Counter Electrodes Decorated with Silver Nanoparticles and Application in Dye-Sensitized Solar Cells

    NASA Astrophysics Data System (ADS)

    Yue, Gentian; Li, Fumin; Yang, Guang; Zhang, Weifeng

    2016-05-01

    We reported a facile two-step electrochemical-chemical approach for in situ growth of nickel sulfide and graphene counter electrode (CE) decorated with silver nanoparticles (signed NiS/Gr-Ag) and served in dye-sensitized solar cells (DSSCs). Under optimum conditions, the DSSC achieved a remarkable power conversion efficiency of 8.36 % assembled with the NiS/Gr-Ag CE, much higher than that based on the Pt CE (7.76 %). The surface morphology of NiS/Gr-Ag CE exhibited a smooth surface with cross-growth of NiS, graphene, and Ag nanoparticles, which was beneficial to the fast mass transport of electrolytes; increased the contact area of electrolytes and active materials; and enabled to speed up the reduction of triiodide to iodide. The research on the electrochemical properties also showed that the NiS/Gr-Ag CE possessed lower charge transfer resistance and more excellent electrocatalytic activity in iodide/triiodide electrolyte compared to the Pt electrode.

  17. Charging of quantum dots by sulfide redox electrolytes reduces electron injection efficiency in quantum dot sensitized solar cells.

    PubMed

    Zhu, Haiming; Song, Nianhui; Lian, Tianquan

    2013-08-07

    In quantum dot (QD) sensitized solar cells (QDSSCs), redox electrolytes act as hole scavengers to regenerate the QD ground state from its oxidized form, thus enabling a continuous device operation. However, unlike molecular sensitizers, QDs also have redox-active trap states within the band gap, which can be charged in the presence of redox electrolyte. The effects of electrolyte induced charging of QDs on the performance of QDSSCs have not been reported. Here, using steady-state and time-resolved absorption and emission spectroscopy, we show that CdSe/CdS3MLZnCdS2MLZnS2ML core/multishell QDs are charged in the presence of sulfide electrolytes due to the reduction of surface states. As a result, exciton lifetimes in these QDs are shortened due to an Auger recombination process. Such charging induced fast Auger recombination can compete effectively with electron transfer from QDs to TiO2 and reduce the electron injection efficiency in QDSSCs. We believe that the reported charging effects are present for most colloidal nanocrystals in the presence of redox media and have important implications for designing QD-based photovoltaic and photocatalytic devices.

  18. Titanium dioxide/zinc indium sulfide hetero-junction: An efficient photoanode for the dye-sensitized solar cell

    NASA Astrophysics Data System (ADS)

    Hou, Wenjing; Xiao, Yaoming; Han, Gaoyi; Zhang, Ying; Chang, Yunzhen

    2016-10-01

    A facile strategy is developed for the fabrication of titanium dioxide/zinc indium sulfide (TiO2/ZnIn2S4) hetero-junction photoanode with an adjustable ZnIn2S4 doping content and application in the dye-sensitized solar cell (DSSC). Comparing to the pure TiO2, TiO2/ZnIn2S4 hetero-junction materials demonstrate an enhanced light utilizing efficiency, a reduced recombination rate of electron-hole pairs, and an accelerated migration process of photoinduced electrons. Due to above merits, DSSC based on TiO2/ZnIn2S4 hetero-junction photoanode achieves a greatly enhanced short-circuit current density, leading to an improved photoelectric conversion efficiency of 8.09% under full sunlight illumination (100 mW cm-2, AM 1.5 G), which is almost 14.43% higher than that of the pure TiO2-based DSSC (7.07%).

  19. Batch slurry photocatalytic reactors for the generation of hydrogen from sulfide and sulfite waste streams under solar irradiation

    SciTech Connect

    Priya, R.; Kanmani, S.

    2009-10-15

    In this study, two solar slurry photocatalytic reactors i.e., batch reactor (BR) and batch recycle reactor with continuous supply of inert gas (BRRwCG) were developed for comparing their performance. The performance of the photocatalytic reactors were evaluated based on the generation of hydrogen (H{sub 2}) from water containing sodium sulfide (Na{sub 2}S) and sodium sulfite (Na{sub 2}SO{sub 3}) ions. The photoreactor of capacity 300 mL was developed with UV-vis transparent walls. The catalytic powders ((CdS/ZnS)/Ag{sub 2}S + (RuO{sub 2}/TiO{sub 2})) were kept suspended by means of magnetic stirrer in the BR and gas bubbling and recycling of the suspension in the BRRwCG. The rate constant was found to be 120.86 (einstein{sup -1}) for the BRRwCG whereas, for the BR it was found to be only 10.92 (einstein{sup -1}). The higher rate constant was due to the fast desorption of products and suppression of e{sup -}/h{sup +} recombination. (author)

  20. An efficient and transparent copper sulfide nanosheet film counter electrode for bifacial quantum dot-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Ke, Weijun; Fang, Guojia; Lei, Hongwei; Qin, Pingli; Tao, Hong; Zeng, Wei; Wang, Jing; Zhao, Xingzhong

    2014-02-01

    Copper sulfide (CuS) with nanosheet structure has been synthesized at a low temperature in situ on copper (Cu) film coated fluorine-doped tin oxide glass and bifacial quantum dot-sensitized solar cells (QDSSCs) were herein developed by using these CuS as counter electrodes (CEs). CuS is an environmental compatible and low toxic material. The obtained two-dimensional CuS nanosheet film presents high carrier mobility and exhibits highly catalytic performance for the polysulfide-based electrolyte. The QDSSC based on a CuS CE presents a power conversion efficiency (PCE) of 3.65% by optimizing the thickness of the Cu film under front illumination. The QDSSC based on a CuS CE prepared with a 200 nm thick Cu film shows a very close PCE under front and rear illuminations in which the values are as high as 2.70% and 2.40%, respectively. All the PCEs of the CuS CEs are much higher than that of the Pt CE (1.34%).

  1. Highly effective nickel sulfide counter electrode catalyst prepared by optimal hydrothermal treatment for quantum dot-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Gopi, Chandu V. V. M.; Srinivasa Rao, S.; Kim, Soo-Kyoung; Punnoose, Dinah; Kim, Hee-Je

    2015-02-01

    Nickel sulfide (NiS) thin film has been deposited on a fluorine-doped tin oxide substrate by a hydrothermal method using 3-mercaptopropionic acid and used as an efficient counter electrode (CE) for polysulfide redox reactions in quantum dot-sensitized solar cells (QDSSCs). NiS has low toxicity and environmental compatibility. In the present study, the size of the NiS nanoparticle increases with the hydrothermal deposition time. The performance of the QDSSCs is examined in detail using polysulfide electrolyte with the NiS CE. A TiO2/CdS/CdSe/ZnS-based QDSSC using the NiS CE shows enhanced photovoltaic performance with a power conversion efficiency (PCE) of 3.03%, which is superior to that of a cell with Pt CE (PCE 2.20%) under one sun illumination (AM 1.5, 100 mW cm-2). The improved photovoltaic performance of the NiS-based QDSSC may be attributed to a low charge transfer resistance (5.08 Ω) for the reduction of polysulfide on the CE, indicating greater electrocatalytic activity of the NiS. Electrochemical impedance spectroscopy, cyclic voltammetry, and Tafel-polarization measurements were used to investigate the electrocatalytic activity of the NiS and Pt CEs.

  2. Green synthesis of wurtzite copper zinc tin sulfide nanocones for improved solar photovoltaic utilization

    NASA Astrophysics Data System (ADS)

    Arora, Leena; Gupta, Poonam; Chhikara, Nitu; Singh, Om Pal; Muhunthan, N.; Singh, V. N.; Singh, B. P.; Jain, Kiran; Chand, S.

    2015-02-01

    Cu2ZnSnS4 (CZTS) is considered to be one of the most promising light absorbing materials for low-cost and high-efficiency thin-film solar cells. It is composed of earth abundant, non-toxic elements. In the present study, wurtzite CZTS nanocone has been synthesized by a green chemistry route. The nanocones have been characterized for its optical, structural and microstructural properties using UV-Vis spectrophotometer, X-ray diffraction, Raman spectroscopy and high-resolution transmission electron microscopy. Optical absorption result shows a band gap of 1.42 eV. XRD and Raman results show wurtzite structure and TEM studies reveal the nanocone structure of the grown material. Growing vertically aligned nanocone structure having smaller diameter shall help in enhancing the light absorption in broader range which shall enhance the efficiency of solar cell. This study is a step in this direction.

  3. Non-Radiative Energy Transfer for Photovoltaic Solar Energy Conversion: Lead Sulfide Quantum Dots on Silicon Nanopillars

    NASA Astrophysics Data System (ADS)

    Lingley, Zachary R.

    This dissertation comprises a study aimed at understanding the competing dynamics of energy and charge transfer in quantum dot (QD) solids and from QDs to crystalline semiconductor substrates to assess a new type of hybrid solar cell that is based on non-radiative resonant energy transfer (NRET) from light absorbers such as nanocrystal QDs to high mobility charge carrier transport channels such as silicon nanopillars. As a platform to investigate a NRET solar cell we employed lead sulfide nanocrystal QDs as light absorbers and silicon as the acceptor transport channel for the NRET generated electrons and holes. Given NRET as the basic physical process at the core of the new type of solar cell the dissertation focused on examining: (1) synthesis of and surface ligand exchange for high quantum efficiency lead sulfide quantum dots, (2) studies of inter-QD NRET and competing inter-QD charge transfer as a function of inter-QD average separation and temperature, (3) structural and optical characteristics of lead sulfide quantum dots adsorbed on crystalline silicon surfaces, and (4) fabrication and examination of prototype colloidal PbS QD - silicon nanopillar array solar cell. The work in these four areas has each provided insights into and new results for the field of quantum dots, QD-based solids, and QD based opto-electronic devices that are of generic value. The need for maintaining the high quantum efficiency (QE) of the as-synthesized PbS QDs while exchanging the surface ligands with new ones better suited for the device lead us to introduce a new approach to ligand exchange that employs pre-conjugated lead cation -- ligand complexes as units that replace the lead cations bound to their as-grown ligand, thus maintaining the Pb-rich stoichiometry that suppresses defect formation while gaining the ability to control the length of the ligands. The ability to control the length of the ligands allowed control over the QD-QD separation in densely packed films referred to

  4. Electric field modulation of photoluminescence in cadmium selenide liquid junction solar cells

    SciTech Connect

    Garuthara, R.; Tomkiewicz, M.; Silberstein, R.P.

    1983-11-01

    We have utilized photoluminescence, modulated by small periodic changes of electrode potential, to study the potential distribution at the surface of single crystal cadmium selenide in contact with an electrolyte. We have shown that at reverse bias and at electrode potentials, not far from the flat-band potential, the modulated photoluminescence is described by the ''dead layer'' theory, in which the electric field in the space-charge layer quenches completely the photoluminescence in that region. The electrical characterization of the interface, based on modulated photoluminescence, agrees well with more conventional impedance measurements.

  5. Transparent conductive oxides of tin, indium, and cadmium for solar cell applications

    NASA Astrophysics Data System (ADS)

    Gorley, Peter; Khomyak, Volodymyr; Horley, Paul; Bilichuk, Sergiy; Bojko, Vyacheslav

    2007-06-01

    This paper presents the investigation results for the technology to obtain the films of SnO II, ITO, and CdO by magnetron sputtering in the pure argon and oxygen-argon mixture, as well as the physical characteristics of the films. For the deposition we have used the substrates made from the quartz glass, sital and silicon. Pure metallic tin, indium and cadmium were used as targets together with the synthesized powder oxides. The authors determined the optimal technological regimes allowing to obtain reproducible high-quality thin films of tin, indium and cadmium oxides with the following electrical and optical parameters: SnO II - specific resistivity ρ = 1.5 - 6.0•10 -4 Ω•cm, optical transmission T = 90 - 95% in transparency region; ITO - ρ = 4.0 - 6.0•10 -4 Ω•cm, T = 90 - 95%; CdO - ρ = 2.0 - 3.0•10 -4 Ω•cm, T = 80 - 90%.

  6. Study of copper sulfide counter electrode on the performances of CdS/CdSe/ZnS-sensitized hierarchical TiO2 spheres quantum dots solar cells

    NASA Astrophysics Data System (ADS)

    Buatong, Nattha; Tang, I.-Ming; Pon-On, Weeraphat

    2015-07-01

    The effects of using copper sulfide (CuS) counter electrodes on the performances of solar cells made with CdS/CdSe/ZnS quantum dots co-sensitized onto hierarchical TiO2 spheres (HTS) used as photoelectrode is reported. The HTS in the QDSSCs is composed of an assembly of numerous TiO2 spheres made by the solvolthermal method. The photoelectrical performance of HTS/CdS/CdSe/ZnS coupled to CuS counter electrode was compared to those coupled to Pt CE. The HTS/CdS/CdSe/ZnS coupled to the CuS CE showed the highest power conversion efficiency η (of 1.310 %.) which is significantly higher than those using a standard Pt CE (η = 0.374%) (3.50 fold). This higher efficiency is the results of the higher electrocatalytic activities when the copper sulfide CEs is used.

  7. Limits on the use of cobalt sulfide as anode of p-type dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Bonomo, Matteo; Congiu, Mirko; De Marco, Maria Letizia; Dowling, Denis P.; Di Carlo, Aldo; Graeff, Carlos F. O.; Dini, Danilo

    2017-06-01

    Thin films of cobalt sulfide (CoS) of thickness l  <  10 µm have been employed as anodes of p-type dye-sensitized solar cells (p-DSCs) when P1-sensitized nickel oxide (NiO) was the photoactive cathode and I3- /I - constituted the redox mediator. In the role of counter electrode for p-DSCs, CoS was preferred over traditional platinized fluorine-doped indium oxide (Pt-FTO) due to the lower cost of the starting materials (Co salts) and the easier procedure of deposition onto large area substrates. The latter process was carried out via direct precipitation of CoS from aqueous solutions. The photoconversion efficiency (η) of the corresponding device was 0.07%. This value is about 35% less than the efficiency that is obtained with the analogous p-DSC employing the Pt-FTO anode (η  =  0.11). Unlike p-DSCs based on Pt-FTO anodes, the photoelectrochemical cells employing CoS electrodes showed that this anodic material was not able to sustain the photocurrent densities generated by P1-sensitized NiO at a given photopotential. Illumination of the p-DSCs with CoS anodes and P1-sensitized NiO cathodes actually induced the reverse bias of the photoelectrochemical cell with CoS behaving like a p-type semiconductor with no degeneracy. Dedicated to Professor Roberto Federici on the occasion of his retirement.

  8. Occupational exposure to arsenic and cadmium in thin-film solar cell production.

    PubMed

    Spinazzè, Andrea; Cattaneo, Andrea; Monticelli, Damiano; Recchia, Sandro; Rovelli, Sabrina; Fustinoni, Silvia; Cavallo, Domenico M

    2015-06-01

    Workers involved in the production of Cd/As-based photovoltaic modules may be routinely or accidentally exposed to As- or Cd-containing inorganic compounds. Workers' exposure to As and Cd was investigated by environmental monitoring following a worst-case approach and biological monitoring from the preparation of the working facility to its decommissioning. Workplace surface contamination was also evaluated through wipe-test sampling. The highest mean airborne concentrations were found during maintenance activities (As = 0.0068 µg m(-3); Cd = 7.66 µg m(-3)) and laboratory simulations (As = 0.0075 µg m(-3); Cd = 11.2 µg m(-3)). These types of operations were conducted for a limited time during a typical work shift and only in specifically suited containment areas, where the highest surface concentrations were also found (laboratory: As = 2.94 µg m(-2), Cd = 167 µg m(-2); powder containment booth: As = 4.35 µg m(-2), Cd = 1500 µg m(-2)). The As and Cd urinary levels (As_u; Cd_u) were not significantly different for exposed (As_u = 6.11±1.74 µg l(-1); Cd_u = 0.24±2.36 µg g(-1) creatinine) and unexposed workers (As_u = 6.11±1.75 µg l(-1); Cd_u = 0.22±2.08 µg g(-1) creatinine). Despite airborne arsenic and cadmium exposure well below the threshold limit value (TLV) when the operation is appropriately maintained in line, workers who are involved in various operations (maintenance, laboratory test) could potentially be at risk of significant exposure, well in excess of the TLV. Nevertheless, the biological monitoring data did not show significant occupationally related arsenic and cadmium intake in workers and no significant changes or differences in arsenic and cadmium urinary level among the exposed and unexposed workers were found. © The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  9. Solar electric and thermal conversion system in close proximity to the consumer. [solar panels on house roofs

    NASA Technical Reports Server (NTRS)

    Boeer, K. W.

    1975-01-01

    Solar cells may be used to convert sunlight directly into electrical energy and into lowgrade heat to be used for large-scale terrestrial solar-energy conversion. Both forms of energy can be utilized if such cells are deployed in close proximity to the consumer (rooftop). Cadmium-sulfide/copper-sulfide (CdS/Cu2S) solar cells are an example of cells which may be produced inexpensively enough to become economically attractive. Cell parameters relevant for combined solar conversion are presented. Critical issues, such as production yield, life expectancy, and stability of performance, are discussed. Systems-design parameters related to operating temperatures are analyzed. First results obtained on Solar One, the experimental house of the University of Delaware, are given. Economic aspects are discussed. Different modes of operation are discussed in respect to the power utility and consumer incentives.

  10. Solar electric and thermal conversion system in close proximity to the consumer. [solar panels on house roofs

    NASA Technical Reports Server (NTRS)

    Boeer, K. W.

    1975-01-01

    Solar cells may be used to convert sunlight directly into electrical energy and into lowgrade heat to be used for large-scale terrestrial solar-energy conversion. Both forms of energy can be utilized if such cells are deployed in close proximity to the consumer (rooftop). Cadmium-sulfide/copper-sulfide (CdS/Cu2S) solar cells are an example of cells which may be produced inexpensively enough to become economically attractive. Cell parameters relevant for combined solar conversion are presented. Critical issues, such as production yield, life expectancy, and stability of performance, are discussed. Systems-design parameters related to operating temperatures are analyzed. First results obtained on Solar One, the experimental house of the University of Delaware, are given. Economic aspects are discussed. Different modes of operation are discussed in respect to the power utility and consumer incentives.

  11. Concentrations of carbonyl sulfide and hydrogen cyanide in the free upper troposphere and lower stratosphere deduced from ATMOS/Spacelab 3 infrared solar occultation spectra

    NASA Technical Reports Server (NTRS)

    Zander, R.; Rinsland, C. P.; Russell, J. M., III; Farmer, C. B.; Norton, R. H.

    1988-01-01

    This paper presents the results on the volume mixing ratio profiles of carbonyl sulfide and hydrogen cyanide, deduced from the spectroscopic analysis of IR solar absorption spectra obtained in the occultation mode with the Atmospheric Trace Molecule Spectroscopy (ATMOS) instrument during its mission aboard Spacelab 3. A comparison of the ATMOS measurements for both northern and southern latitudes with previous field investigations at low midlatitudes shows a relatively good agreement. Southern Hemisphere volume mixing ratio profiles for both molecules were obtained for the first time, as were the profiles for the Northern Hemisphere covering the upper troposphere and the lower stratosphere simultaneously.

  12. Ferrocene-graphene sheets for high-efficiency quenching of electrochemiluminescence from Au nanoparticles functionalized cadmium sulfide flower-like three dimensional assemblies and sensitive detection of prostate specific antigen.

    PubMed

    Yang, Jiu-Jun; Cao, Jun-Tao; Wang, Hui; Liu, Yan-Ming; Ren, Shu-Wei

    2017-05-15

    A signal-switchable electrochemiluminescence (ECL) aptasensor was presented for sensitive prostate specific antigen (PSA) assay using ferrocene-graphene sheets (Fc-GNs) for high-efficiency quenching of ECL from Au nanoparticles functionalized cadmium sulfide flower-like three dimensional (3D) assemblies (Au-CdS flower-like 3D assemblies). Au-CdS flower-like 3D assemblies were synthesized and employed as luminophore, exhibiting strong and stable ECL intensity, and followed by assembling captured DNA (cDNA) and hybridizing it with half of base sequence of PSA aptamer on the Au-CdS flower-like 3D assemblies modified electrode. The remaining part of the non-complementary base of the aptamer could preferentially adsorb GN with the signal switched "off" state. While in the presence of the PSA, the binding of PSA with aptamer caused desorption of aptamer from the surface of Fc-GNs and was then released from electrode surface, thus allowing the ECL signal enhancement. With the transformation of luminescence signal from "off" to "on", the aptasensor displays high sensitivity for PSA detection with a linear range from 1pgmL(-1) to 25ngmL(-1) and a detection limit of 0.38pgmL(-1)S/N=3). Moreover, this developed method could be successfully applied to the determination of PSA in human serum samples with recoveries of 85.8-104.0%, suggesting great potential applications in biochemical analysis.

  13. PHOTOVOLTAIC AND THERMOELECTRIC SOLAR ENERGY CONVERSION USING THIN FILMS,

    DTIC Science & Technology

    Solar energy conversion by the use of thin films in photovoltaic and thermoelectric devices is discussed. Experimental work is presented on the fabrication of a thin film cadmium sulfide cell which utilizes the photovoltaic effect. A theoretical investigation is made of the temperature differences obtainable in space by using thin, light-weight plastic sheets, and the use of such plastics for thermoelectric generators is discussed. Temperature differences of several hundred centrigrade degrees can be obtained. (Author)

  14. Selenium Sulfide

    MedlinePlus

    Selenium sulfide, an anti-infective agent, relieves itching and flaking of the scalp and removes the dry, ... Selenium sulfide comes in a lotion and is usually applied as a shampoo. As a shampoo, selenium ...

  15. High efficiency cadmium and zinc telluride-based thin film solar cells

    SciTech Connect

    Rohatgi, A.; Summers, C.J.; Erbil, A.; Sudharsanan, R.; Ringel, S. . School of Electrical Engineering)

    1990-10-01

    Polycrystalline Cd{sub 1-x}Zn{sub x}Te and Cd{sub 1-x}Mn{sub x}Te films with a band gap of 1.7 eV were successfully grown on glass/SnO{sub 2}/CdS substrates by molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD), respectively. Polycrystalline Cd{sub 1-x}Zn{sub x}Te films grown by MBE resulted in uniform composition and sharp interfaces. However, polycrystalline Cd{sub 1-x}Mn{sub x}Te films grown by MOCVD showed nonuniform compositions and evidence of manganese accumulation at the Cd{sub 1-x}Mn{sub x}Te/CdS interface. We found that manganese interdiffuses and replaces cadmium in the CdS film. By improving the CdTe/CdS interface and, thus, reducing the collection function effects, the efficiency of the MOCVD CdTe cell can be improved to about 13.5%. MBE-grown CdTe cells also produced 8%--9% efficiencies. The standard CdTe process was not optimum for ternary films and resulted in a decrease in the band gap. Recent results indicate that CdCl{sub 2} + ZnCl{sub 2} chemical treatment may prevent the band-gap reduction, and that chromate etch (rather than bromine etch) may provide the solution to contact resistance in the ternary cells.

  16. The role of acid-volatile sulfide and interstitial water metal concentrations in determining bioavailability of cadmium and nickel from contaminated sediments to the marine polychaete Neanthes arenaceodentata

    SciTech Connect

    Pesch, C.E.; Hansen, D.J.; Boothman, W.S. . Environmental Research Lab.); Berry, W.J. ); Mahony, J.D. . Chemistry Dept.)

    1995-01-01

    This study investigated the influence of acid-volatile sulfide (AVS) and interstitial water (IW) metal concentrations on bioavailability and toxicity of Cd and Ni to an infaunal sediment-ingesting marine worm, Neanthes Arenaceodentata. Ten-d exposures were conducted with sediments, contaminated primarily with Cd and Ni, from Foundry Cove (Hudson River, NY), and with uncontaminated sediments spiked with Cd or Ni. Molar ratios of simultaneously extracted metal (SEM)/AVS ranged from < 0.02 to 44 for Cd-spiked, 0.02 to 241 for Ni-spiked, and <0.06 to 125 for Foundry Cove sediments. In all experiments, significant mortality was not observed when SEM/AVS ratios were <1.0 and interstitial water toxic units (IWTU) were <1.0. In the Cd and Ni-spiked experiments, when SEM/AVS ratios or IWTUs were >1.0, sediments were either lethal or worms did not burrow. Mortality of worms in Foundry Cove sediments was [le] 20%, and worms burrowed in all these sediments. However, IW contained <1.0 TU (Ni + Cd) in all Foundry Cove sediments except one (IWTU = 1.69). Metal concentrations in worms generally increased with increases in sediment metal concentration, SEM/AVS molar ratio, and IW metal concentration. The presence of metal in worms from sediments from SEM/AVS ratios <1.0 may be evidence of release of Cd or Ni from oxidized metal sulfide (a result of burrowing), uptake of metal from ingested sediment, or adsorption to body surfaces. These results support the hypothesis that when the concentration of AVS in sediments exceeds that of divalent metals sediments will not be acutely toxic. However, a greater number of sediments was correctly predicted to be nontoxic when interstitial water metal concentration of <1.0 TU was used.

  17. Exploring the main function of reduced graphene oxide nano-flakes in a nickel cobalt sulfide counter electrode for dye-sensitized solar cell

    NASA Astrophysics Data System (ADS)

    Lu, Man-Ning; Lin, Jeng-Yu; Wei, Tzu-Chien

    2016-11-01

    Addition of carbonaceous materials into transition metal sulfide counter electrode (CE) of a dye-sensitized solar cell (DSSC) is a common method to improve the performance of the CE and consequent photovoltaic performance. This improvement is almost without exception attributed to the improvement of overall conductivity after the carbonaceous material addition; however, the root function of these carbonaceous materials in promoting the solar cell efficiency is seldom discussed. In this study, highly crystallized nickel cobalt sulfide (NCS) micro-particles were mixed with a small portion of home-made reduced graphene oxide (rGO) nano-flakes. This NCS/rGO hybrid is subjected to extensive characterizations including X-ray diffraction, Raman spectroscopy, field emission scanning microscopy and electrochemical impedance spectroscopy. It is found that the rGO acts bi-functionally including a co-catalyst in accelerating the tri-iodide reduction for the main NCS catalysts, conductivity promotor to decrease the series resistance of the CE. Proved by electrochemical impedance spectroscopy, it is confirmed that the decrease in series resistance is less insignificant than that in charge transfer resistance, indicating rGO functions more profoundly as a co-catalyst than as a conductivity promotor. Moreover, an argument to highlight the requirement of a CE in a dim-light optimized DSSC is also proposed.

  18. Platinum-Free Counter Electrode Comprised of Metal-Organic-Framework (MOF)-Derived Cobalt Sulfide Nanoparticles for Efficient Dye-Sensitized Solar Cells (DSSCs)

    NASA Astrophysics Data System (ADS)

    Hsu, Shao-Hui; Li, Chun-Ting; Chien, Heng-Ta; Salunkhe, Rahul R.; Suzuki, Norihiro; Yamauchi, Yusuke; Ho, Kuo-Chuan; Wu, Kevin C.-W.

    2014-11-01

    We fabricated a highly efficient (with a solar-to-electricity conversion efficiency (η) of 8.1%) Pt-free dye-sensitized solar cell (DSSC). The counter electrode was made of cobalt sulfide (CoS) nanoparticles synthesized via surfactant-assisted preparation of a metal organic framework, ZIF-67, with controllable particle sizes (50 to 320 nm) and subsequent oxidation and sulfide conversion. In contrast to conventional Pt counter electrodes, the synthesized CoS nanoparticles exhibited higher external surface areas and roughness factors, as evidenced by X-ray diffraction (XRD), scanning electron microscopy (SEM) element mapping, and electrochemical analysis. Incident photon-to-current conversion efficiency (IPCE) results showed an increase in the open circuit voltage (VOC) and a decrease in the short-circuit photocurrent density (Jsc) for CoS-based DSSCs compared to Pt-based DSSCs, resulting in a similar power conversion efficiency. The CoS-based DSSC fabricated in the study show great potential for economically friendly production of Pt-free DSSCs.

  19. Platinum-Free Counter Electrode Comprised of Metal-Organic-Framework (MOF)-Derived Cobalt Sulfide Nanoparticles for Efficient Dye-Sensitized Solar Cells (DSSCs)

    PubMed Central

    Hsu, Shao-Hui; Li, Chun-Ting; Chien, Heng-Ta; Salunkhe, Rahul R.; Suzuki, Norihiro; Yamauchi, Yusuke; Ho, Kuo-Chuan; Wu, Kevin C.-W.

    2014-01-01

    We fabricated a highly efficient (with a solar-to-electricity conversion efficiency (η) of 8.1%) Pt-free dye-sensitized solar cell (DSSC). The counter electrode was made of cobalt sulfide (CoS) nanoparticles synthesized via surfactant-assisted preparation of a metal organic framework, ZIF-67, with controllable particle sizes (50 to 320 nm) and subsequent oxidation and sulfide conversion. In contrast to conventional Pt counter electrodes, the synthesized CoS nanoparticles exhibited higher external surface areas and roughness factors, as evidenced by X-ray diffraction (XRD), scanning electron microscopy (SEM) element mapping, and electrochemical analysis. Incident photon-to-current conversion efficiency (IPCE) results showed an increase in the open circuit voltage (VOC) and a decrease in the short-circuit photocurrent density (Jsc) for CoS-based DSSCs compared to Pt-based DSSCs, resulting in a similar power conversion efficiency. The CoS-based DSSC fabricated in the study show great potential for economically friendly production of Pt-free DSSCs. PMID:25382139

  20. Surface oxidation of polycrystalline cadmium telluride thin films for Schottky barrier junction solar cells

    NASA Astrophysics Data System (ADS)

    Yi, X.; Liou, J. J.

    1995-06-01

    Polycrystalline CdTe thin films grown on graphite or tungsten-coated graphite substrates by chemical vapor deposition (CVD) were exposed to the air at room temperature in a natural atmosphere of about 60% air humidity for 6 months. X-ray photoemission spectroscopy (XPS) and Auger electron spectroscopy (AES) of the films indicate that a tellurium dioxide (TeO 2) overlayer has formed from this process. The effects of such an overlayer on the electrical property of polycrystalline CdTe-based Schottky barrier junction solar cells have also been discussed for the first time. It is shown that a solar cell formed on a CdTe film with TeO 2 overlayer has considerably higher open-circuit voltage and fill factor than that formed on a CdTe film without TeO 2 overlayer. Our study further indicates that using a polycrystalline CdTe film which is thermally oxidized at above room temperature (100-400°C) does not provide any improvement on the solar cell efficiency.

  1. Development of Materials and Structures for p-type Contacts in Cadmium Telluride Solar Cells

    NASA Astrophysics Data System (ADS)

    Ferizovic, Dino

    Solar cells based on CdTe absorbers are attractive due to the optimal direct band gap energy and large absorption coefficient of CdTe, however, their performance and commercialization is hindered by the lack of reliable p-type contacts. CdTe has a low carrier concentration and a large electron affinity, which results in a requirement of non-realistic work functions for metals to be used as back contacts in the solar cell. Even noble metals such as Ag present a significantly large potential barrier for holes, thereby reducing the hole current through the semiconductor/metal interface. Several attempts to resolve this challenge have been tried, however, many drawbacks have been encountered. Two particular systems, namely Cu2Te thin films and CdTe/ZnTe strained-layer superlattices, are investigated for their potential use as ohmic contacts in CdTe solar cells. A detailed analysis of the optical, electrical, and structural properties of Cu2Te thin films deposited by magnetron sputtering is presented. It is shown that these films have an indirect band gap and highly degenerate semiconductor behavior. The large p-type carrier concentration of Cu2Te films is highly desirable for the application of Cu2Te as a p-type contact to CdTe. In-depth studies of optical transitions and miniband transport in strained-layer CdTe/ZnTe superlattices are presented as well. The band offsets between CdTe and ZnTe were determined by comparison of measured and calculated optical transitions. Superlattice structures that offer best contact performance have been identified by use of tunneling probability simulations. Characterization of CdTe solar cells with above mentioned contacts indicated that contacts based on CdTe/ZnTe superlattices are a viable Cu free option for stable and reliable p-type contacts in CdTe solar cell. The contact performance of Cu2Te thin films was comparable to that of CdTe/ZnTe superlattices and both demonstrated an advantage over contacts based on ZnTe:N thin films

  2. Determination of Hydrogen Sulfide in Fermentation Broths Containing SO21

    PubMed Central

    Acree, T. E.; Sonoff, Elisabeth P.; Splittstoesser, D. F.

    1971-01-01

    A procedure for the determination of hydrogen sulfide in fermentation broths containing up to 100 μg of SO2 per ml is described. The method involves the sparging of H2S from the broth into a cadmium hydroxide absorption solution, the formation of methylene blue from the absorbed sulfide, and the measuring of this color spectrophotometrically. The use of cadmium hydroxide instead of zinc acetate, the common absorbent, substantially reduced the interference of SO2 with the analysis. PMID:5111300

  3. Electron-reflector strategy for cadmium telluride thin-film solar cells

    NASA Astrophysics Data System (ADS)

    Hsiao, Kuo-Jui

    The CdTe thin-film solar cell has a large absorption coefficient and high theoretical efficiency. Moreover, large-area photovoltaic panels can be economically fabricated. These features potentially make the CdTe thin-film solar cell the leading alternative energy source. However, the record CdTe efficiency (16.5%) is much less than its theoretical maximum efficiency (29%), primarily because the open-circuit voltage (0.845 V) is well below what is expected for its band gap (1.5 eV). The incorporation of an electron reflector is a strategy to improve the open-circuit voltage of solar cells, and thus a strong possibility to improve the efficiency of CdTe thin-film solar cells. An electron reflector is a conduction-band energy barrier at the back surface of the solar cell, which can reduce the recombination due to the electron flow to the back surface. Different methods to create an electron reflector are explained in the thesis: (1) expanded band gap, either an expanded-band-gap layer or a bulk-band-gap reduction, and (2) alteration to the band bending through a reversed back barrier or a heavily-doped back surface. Investigation shows that the expanded-band-gap layer is the most efficient and practical mechanism for an electron reflector, and the combination of any two mechanisms does not yield additional improvement. To have the optimal effect from the electron-reflector strategy, reasonable CdTe lifetime (1 ns or above) and full depletion of the CdTe layer are required to ensure high carrier collection. Furthermore, a good-quality reflector interface between the p-type CdTe layer and the electron-reflector layer is essential. Preliminary experimental evidence has shown that CdTe cells with a ZnTe back layer do have a slightly higher open-circuit voltage. An electron reflector should be particularly beneficial for thin (less than 2 microm) CdTe cells which have a fully-depleted CdTe absorber layer. Thin CdTe cells can also benefit from the optical reflection at the

  4. Drift Mobility Measurements and Electrical Characterization in Thin Film Cadmium Telluride Solar Cells

    NASA Astrophysics Data System (ADS)

    Long, Qi

    Thin film CdTe solar cells are leading the production in the thin film photovoltaic industry for the recent few years. The electric properties and mechanism for fabrication of high efficiency solar cells are still not well established. In this thesis, I'll report electron and hole drift mobilities measurements in thin film CdTe solar cells based on two characterization methods: time-of-flight and photocapacitance. For a deposition process similar to that used for high-efficiency cells, the electron drift mobilities are in the range 10-1 -- 100 cm2/Vs, and holes are in the range 100 -- 101 cm2/Vs. The electron drift mobilities are three orders of magnitude smaller than those measured in single crystal CdTe, the hole mobilities are about ten times smaller. Cells were examined before and after a vapor phase treatment with CdCl2; treatment had little effect on the hole drift mobility, but decreased the electron mobility. The electron mobility shows an interesting inverse correlation with the open-circuit voltage for the CdTe coupons with and without the CdCl2 treatment. We speculate that this correlation is due to the diffusion limited recombination. We also discuss the mechanisms reducing the mobilities from the single crystal values. In this thesis, we are able to exclude bandtail trapping and dispersion as a mechanism for the small drift mobilities in thin film CdTe. Other mechanisms like classic scattering, grain boundaries effect, and also polaron interaction will also be discussed in this thesis. All mechanisms mentioned above show little evidence on the influence to the mobility value. The true reason for such a huge change of the drift mobility from its single crystal values still need more interpretations.

  5. Flight experience of Solar Mesosphere Explorer's two nickel-cadmium batteries

    NASA Technical Reports Server (NTRS)

    Faber, J.

    1985-01-01

    The performance of the power system on the solar mesosphere explorer (SME) since launch is discussed. Predictions for continued operation for the rest of the project mission are also discussed. The SME satellite's power system was characterized by both insufficient loading and excessive battery charging during the first year of the mission. These conditions affected battery performance and jeopardized the long-term mission. Increased loading on selected orbits has improved battery performance. Long term projections indicate steadily increasing temperatures for the remainder of the mission.

  6. Non-Uniformities in Thin-Film Cadmium Telluride Solar Cells Using Electroluminescence and Photoluminescence: Preprint

    SciTech Connect

    Zaunbrecher, K.; Johnston, S.; Yan, F.; Sites, J.

    2011-07-01

    It is the purpose of this research to develop specific imaging techniques that have the potential to be fast, in-line tools for quality control in thin-film CdTe solar cells. Electroluminescence (EL) and photoluminescence (PL) are two techniques that are currently under investigation on CdTe small area devices made at Colorado State University. It is our hope to significantly advance the understanding of EL and PL measurements as applied to CdTe. Qualitative analysis of defects and non-uniformities is underway on CdTe using EL, PL, and other imaging techniques.

  7. Preparation, crystal structure, and thermal stability of the cadmium sulfide nanoclusters Cd6S44+ and Cd2Na2S4+in the sodalite cavities of zeolite A (LTA).

    PubMed

    Kim, Seok Han; Heo, Nam Ho; Kim, Ghyung Hwa; Hong, Suk Bong; Seff, Karl

    2006-12-28

    The crystal structure and thermal stability of two cadmium sulfide nanoclusters prepared in zeolite A (LTA) have been studied by XPS, TGA, and single-crystal and powder XRD. The crystal structures of Cd2.4Na3.2(Cd6S4)0.4(Cd2Na2S)0.6(H2O)> or =5.8[Si12Al12O48]-LTA (a = 12.2919(7) A, crystal 1 (hydrated)) and /Cd4Na2(Cd2O)(Na2O)/[Si12Al12O48]-LTA (a = 12.2617(4) A, crystal 2 (dehydrated)) were determined by single-crystal methods in the cubic space group Pm3m at 294(1) K. Crystal 1 was prepared by ion exchange of Na12-LTA in an aqueous stream 0.05 M in Cd2+, followed by washing in a stream of water, followed by reaction in an aqueous stream 0.05 M in Na2S. Crystal 2 was made by dehydrating crystal 1 at 623 K and 1 x 10(-6) Torr for 3 days. In crystal 1, Cd6S4(4+) nanoclusters were found in and extending out of about 40% of the sodalite cavities. Central to each Cd6S4(4+) cluster is a Cd4S4 unit (interpenetrating Cd2+ and S2- tetrahedra with near Td symmetry, Cd-S = 2.997(24) A, Cd-S-Cd = 113.8(12) degrees, and S-Cd-S = 58.1(24) degrees). Each of the two remaining Cd2+ ions bonds radially through a 6-ring of the zeolite framework to a sulfide ion of this Cd4S4 unit (Cd-S = 2.90(8) A). In each of the remaining 60% of the sodalite cavities of crystal 1, a planar Cd2Na2S4+ cluster was found (Cd-S/Na-S = 2.35(5)/2.56(14) A and Cd-S-Cd/Na-S-Na = 122(5)/92(7) degrees). Cd6S4(4+) and Cd2Na2S4+ are stable within the zeolite up to about 700 K in air. Upon vacuum dehydration at 623 K, all sulfur was lost (crystal 2). Instead as anions, only two oxide ions remain per sodalite unit. One bridges between two Cd2+ ions (Cd2O2+, Cd-O = 2.28(3) A) and the other between two Na+ ions (Na2O, Na-O = 2.21(10) A).

  8. A ternary photocatalyst of graphitic carbon nitride/cadmium sulfide/titania based on the electrostatic assembly using two-dimensional semiconductor nanosheets.

    PubMed

    Zhou, Chenjuan; Qian, Jiajia; Yan, Jing; Dong, Xiaoping; Zhou, Baocheng

    2017-04-01

    Herein, we employed the exfoliated two-dimensional (2D) graphitic carbon nitride nanosheets (CNNS) and titania nanosheets (TNS) as building blocks, and these negatively charged nanosheets were flocculated by Cd(2+) ions with a followed sulfidation treatment to produce a ternary heterostructure photocatalyst of CNNS/CdS/TNS. This novel nanocomposite exhibited outstanding absorption in visible spectral region, and meanwhile its gradient band structure and the closed interface promoted the separation of photo-generated charge. The relative content of CNNS and TNS in the ternary nanocomposite was optimized, and the optimal photocatalyst with a CNNS/TNS mass ratio of 98:2 could rapidly remove 10mgL(-1) rhodamine B (RhB) in 20min under visible light irradiation. The calculated rate constant of CNNS/CdS/TNS was 56.87, 12.18, and 6.67 times higher than those of the restacked CNNS and TNS and the individual CdS, as well as 8.31, 6.22 and 2.57 times higher than those of binary CNNS/TNS, CdS/TNS and CdS/CNNS photocatalysts, respectively. Moreover, this nanocomposite possessed a superior durability and universality for degradation of RhB in different concentration and other organic pollutants, including dyes and colorless compounds. Finally, the possible photocatalytic mechanism was proposed based on the theoretical calculation and the active species quenching experiment.

  9. Development of window layer for high efficiency high bandgap cadmium selenide solar cell for 4-terminal tandem solar cell applications

    NASA Astrophysics Data System (ADS)

    Vakkalanka, Sridevi A.

    Tandem solar cells fabricated from thin films provide promise of improved efficiency while keeping the processing costs low. CdSe as top cell are investigated in this work. CIGS has been a standardized process with lab efficiencies reaching 18% [53]. This dissertation focuses on the development of conductive window layer for the development of a high performance, high bandgap solar cell. ZnSe, Cu2-xSe, and ZnSexTe1-x are investigated as viable window layers of the top cell. ZnSe in undoped form forms a good junction with CdSe films, but the Voc from these devices could never exceed the 360mV mark, while the current densities approached 17.5mA/cm2 [61].To improve Voc's, the high contact energy at the ZnSe/Cu interface has to be overcome by replacing Cu with a metal having higher work function or doping the window layer to form a tunneling contact with Copper. Deposition of ZnSe from binary sources in presence of nitrogen plasma resulted in films with proper stoichiometry. However, doping could not be accomplished. ZnTe is easily dopable, and was the next alternative. ZnTe doping in presence of Nitrogen plasma resulted in Zn rich films. Hence doping of the ternary compound ZnSexTe1-x was considered. This work focuses on studying the effects of compositional variation on the conductivity of the ZnSexTe1-x films. ZnSexTe1-x films were doped using Nitrogen. Films were deposited by co-evaporation from ZnTe, ZnSe and Se sources. Te/Se ratio was varied by varying the ZnTe thickness and Se Thickness. Films with Zn/Group VI ratio close to 1 were measured for conductivity using IV measurements. Highest conductivity of 2* 10 -8 O-cm was obtained at ZnSe, ZnTe, and Se thicknesses of 2000A, 1500A, and 500A respectively. The actual carrier concentration could be concealed by the current limiting Cu contacts. All films with Zn/Group VI ratio close to 1 showed slight conductivity in the 10-10 O-cm range. Layered ZnSexTe1-x Films doped with Nitrogen had targeted Zn/Group VI ratio of

  10. Oxidation of polycrystalline materials based on zinc and cadmium chalcogenides

    SciTech Connect

    Gunchenko, N.N.; Dronova, G.N.; Maksimova, I.A.; Mironov, I.A.; Pavlova, V.N.; Pevtsova, N.I.

    1988-06-01

    The resistance of polycrystalline zinc sulfide and selenide and cadmium telluride to atmospheric exposure in heating to 300-700/degrees/C was investigated. Polycrystalline zinc sulfide (KO-2 optical ceramic) was prepared by hot powder molding and zinc selenide and cadmium telluride were prepared by evaporation with filtrations of vapors through porous materials and subsequent condensation on a heated support. Zinc sulfide was most sensitive to oxidation. The rate of oxidation of polycrystals was slightly higher than for single crystals. The possibility of using oxidation for creating protective and antireflective coatings on zinc sulfide and selenide should be noted.

  11. Study of copper-free back contacts to thin film cadmium telluride solar cells

    NASA Astrophysics Data System (ADS)

    Viswanathan, Vijay

    The goals of this project are to study Cu free back contact alternatives for CdS/CdTe thin film solar cells, and to research dry etching for CdTe surface preparation before contact application. In addition, an attempt has been made to evaluate the stability of some of the contacts researched. The contacts studied in this work include ZnTe/Cu2Te, Sb2Te 3, and Ni-P alloys. The ZnTe/Cu2Te contact system is studied as basically an extension of the earlier work done on Cu2Te at USF. RF sputtering from a compound target of ZnTe and Cu2Te respectively deposits these layers on etched CdTe surface. The effect of Cu2Te thickness and deposition temperature on contact and cell performance will be studied with the ZnTe depositions conditions kept constant. C-V measurements to study the effect of contact deposition conditions on CdTe doping will also be performed. These contacts will then be stressed to high temperatures (70--100°C) and their stability with stress time is analyzed. Sb2Te3 will be deposited on glass using RF sputtering, to study film properties with deposition temperature. The Sb2Te 3 contact performance will also be studied as a function of the Sb 2Te3 deposition temperature and thickness. The suitability of Ni-P alloys for back contacts to CdTe solar cells was studied by forming a colloidal mixture of Ni2P in graphite paste. The Ni-P contacts, painted on Br-methanol etched CdTe surface, will be studied as a function of Ni-P concentration (in the graphite paste), annealing temperature and time. Some of these cells will undergo temperature stress testing to determine contact behavior with time. Dry etching of CdTe will be studied as an alternative for wet etching processes currently used for CdTe solar cells. The CdTe surface is isotropically etched in a barrel reactor in N2, Ar or Ar:O 2 ambient. The effect of etching ambient, pressure, plasma power and etch time on contact performance will be studied.

  12. High efficiency cadmium telluride and zinc telluride based thin-film solar cells

    SciTech Connect

    Rohatgi, A.; Sudharsanan, R.; Ringel, S.A.; Chou, H.C. )

    1992-10-01

    This report describes work to improve the basic understanding of CdTe and ZnTe alloys by growing and characterizing these films along with cell fabrication. The major objective was to develop wide-band-gap (1.6--1.8 eV) material for the top cell, along with compatible window material and transparent ohmic contacts, so that a cascade cell design can be optimized. Front-wall solar cells were fabricated with a glass/SnO{sub 2}/CdS window, where the CdS film is thin to maximize transmission and current. Wide-band-gap absorber films (E{sub g} = 1.75 eV) were grown by molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD) techniques, which provided excellent control for tailoring the film composition and properties. CdZnTe films were grown by both MBE and MOCVD. All the as-grown films were characterized by several techniques (surface photovoltage spectroscopy, Auger electron spectroscopy (AES), and x-ray photoelectron spectroscopy (XPS)) for composition, bulk uniformity, thickness, and film and interface quality. Front-wall-type solar cells were fabricated in collaboration with Ametek Materials Research Laboratory using CdTe and CdZnTe polycrystalline absorber films. The effects of processing on ternary film were studied by AES and XPS coupled with capacitance voltage and current voltage measurements as a function of temperature. Bias-dependent spectral response and electrical measurements were used to test some models in order to identify and quantify dominant loss mechanisms.

  13. Analysis of advanced vapor source for cadmium telluride solar cell manufacturing

    NASA Astrophysics Data System (ADS)

    Khetani, Tejas Harshadkumar

    A thin film CdS/CdTe solar cell manufacturing line has been developed in the Materials Engineering Laboratory at Colorado State University. The original design incorporated infrared lamps for heating the vapor source. This system has been redesigned to improve the energy efficiency of the system, allow co-sublimation and allow longer run time before the sources have to be replenished. The advanced vapor source incorporates conduction heating with heating elements embedded in graphite. The advanced vapor source was modeled by computational fluid dynamics (CFD). From these models, the required maximum operating temperature of the element was determined to be 720 C for the processing of CdS/CdTe solar cells. Nichrome and Kanthal A1 were primarily selected for this application at temperature of 720 °C in vacuum with oxygen partial pressure. Research on oxidation effects and life due to oxidation as well as creep deformation was done, and Nichrome was found more suitable for this application. A study of the life of the Nichrome heating elements in this application was conducted and the estimate of life is approximately 1900 years for repeated on-off application. This is many orders of magnitude higher than the life of infrared heat lamps. Ceramic cement based on aluminum oxide (Resbond 920) is used for bonding the elements to the graphite. Thermodynamic calculations showed that this cement is inert to the heating element. An earlier design of the advanced source encountered failure of the element. The failed element was studies by scanning electron microscopy and the failure was attributed to loss of adhesion between the graphite and the ceramic element. The design has been modified and the advanced vapor source is currently in operation.

  14. Polycrystalline thin-film cadmium telluride solar cells fabricated by electrodeposition. Annual technical report

    SciTech Connect

    Trefny, J.U.; Mao, D.

    1998-01-01

    During the past year, Colorado School of Mines (CSM) researchers performed systematic studies of the growth and properties of electrodeposition CdS and back-contact formation using Cu-doped ZnTe, with an emphasis on low Cu concentrations. CSM also started to explore the stability of its ZnTe-Cu contacted CdTe solar cells. Researchers investigated the electrodeposition of CdS and its application in fabricating CdTe/CdS solar cells. The experimental conditions they explored in this study were pH from 2.0 to 3.0; temperatures of 80 and 90 C; CdCl{sub 2} concentration of 0.2 M; deposition potential from {minus}550 to {minus}600 mV vs. Ag/AgCl electrode; [Na{sub 2}S{sub 2}O{sub 4}] concentration between 0.005 and 0.05 M. The deposition rate increases with increase of the thiosulfate concentration and decrease of solution pH. Researchers also extended their previous research of ZnTe:Cu films by investigating films doped with low Cu concentrations (< 5 at. %). The low Cu concentration enabled them to increase the ZnTe:Cu post-annealing temperature without causing excessive Cu diffusion into CdTe or formation of secondary phases. The effects of Cu doping concentration and post-deposition annealing temperature on the structural, compositional, and electrical properties of ZnTe were studied systematically using X-ray diffraction, atomic force microscopy, electron microprobe, Hall effect, and conductivity measurements.

  15. Self-photosensitization of nonphotosynthetic bacteria for solar-to-chemical production.

    PubMed

    Sakimoto, Kelsey K; Wong, Andrew Barnabas; Yang, Peidong

    2016-01-01

    Improving natural photosynthesis can enable the sustainable production of chemicals. However, neither purely artificial nor purely biological approaches seem poised to realize the potential of solar-to-chemical synthesis. We developed a hybrid approach, whereby we combined the highly efficient light harvesting of inorganic semiconductors with the high specificity, low cost, and self-replication and -repair of biocatalysts. We induced the self-photosensitization of a nonphotosynthetic bacterium, Moorella thermoacetica, with cadmium sulfide nanoparticles, enabling the photosynthesis of acetic acid from carbon dioxide. Biologically precipitated cadmium sulfide nanoparticles served as the light harvester to sustain cellular metabolism. This self-augmented biological system selectively produced acetic acid continuously over several days of light-dark cycles at relatively high quantum yields, demonstrating a self-replicating route toward solar-to-chemical carbon dioxide reduction. Copyright © 2016, American Association for the Advancement of Science.

  16. Radio-frequency magnetron triode sputtering of cadmium telluride and zinc telluride films and solar cells

    NASA Astrophysics Data System (ADS)

    Sanford, Adam Lee

    The n-CdS/p-CdTe solar cell has been researched for many years now. Research groups use a variety of processes to fabricate thin-film CdS/CdTe cells, including physical vapor deposition, chemical vapor deposition, and RF diode sputtering. One of the central areas of investigation concerning CdS/CdTe cells is the problem of a Schottky barrier at the back contact. Even cells fabricated with ohmic back contacts degrade into Schottky barriers as the devices are used. This severely degrades power generation. One possible solution is to use p+-ZnTe as an interlayer between CdTe and the back contact. ZnTe is easily doped with Cu to be p-type. However, even contacts with this ZnTe interlayer degrade over time, because Cu is highly mobile and diffuses away from the contact towards the CdS/CdTe junction. Another possibility is to dope ZnTe with N. It has been demonstrated using molecular beam epitaxy and RF diode sputtering. In this study, CdTe films are fabricated using a variation of RF diode sputtering called triode sputtering. This technique allows for control of ion bombardment to the substrate during deposition. Also, a higher plasma density near the target is achieved allowing depositions at lower pressures. These films are characterized structurally to show the effects of the various deposition parameters. N-doped ZnTe films are also fabricated using this technique. These films are characterized electrically to show the effects of the various deposition parameters. Also, the effects of post-deposition annealing are observed. It is found that annealing at the right temperature can increase the conductivity of the films by a factor of 3 or more. However, annealing at higher temperatures decreases the conductivity to as low as 12% of the initial conductivity. Finally, RF triode sputtered N-doped ZnTe films are used as an interlayer at the back contact of a CdS/CdTe solar cell. The effects of annealing the device before and after contact deposition are observed

  17. Role of the copper-oxygen defect in cadmium telluride solar cells

    NASA Astrophysics Data System (ADS)

    Corwine, Caroline R.

    Thin-film CdTe is one of the leading materials used in photovoltaic (PV) solar cells. One way to improve device performance and stability is through understanding how various device processing steps alter defect states in the CdTe layer. Photoluminescence (PL) studies can be used to examine radiative defects in materials. This study uses low-temperature PL to probe the defects present in thin-film CdTe deposited for solar cells. One key defect seen in the thin-film CdTe was reproduced in single-crystal (sX) CdTe by systematic incorporation of known impurities in the thin-film growth process, hence demonstrating that both copper and oxygen were necessary for its formation. Polycrystalline (pX) thin-film glass/SnO2:F/CdS/CdTe structures were examined. The CdTe layer was grown via close-spaced sublimation (CSS), vapor transport deposition (VTD), and physical vapor deposition (PVD). After CdTe deposition, followed by a standard CdC12 treatment and a ZnTe:Cu back contact, a PL peak was seen at ˜1.46 eV from the free back surface of all samples (1.456 eV for CSS and PVD, 1.460-1.463 eV for VTD). However, before the Cu-containing contact was added, this peak was not seen from the front of the CdTe (the CdS/CdTe junction region) in any device with CdTe thickness greater than 4 mum. The CdCl2 treatment commonly used to increase CdTe grain size did not enhance or reduce the peak at ˜1.46 eV relative to the rest of the PL spectrum. When the Cu-containing contact was applied, the PL spectra from both the front and back of the CdTe exhibited the peak at 1.456 eV. The PL peak at ˜1.46 eV was present in thin-film CdTe after deposition, when the dominant impurities are expected to be both Cu from the CdTe source material and O introduced in the chamber during growth to assist in CdTe film density. Since Cu and/or O appeared to be involved in this defect, PL studies were done with sX CdTe to distinguish between the separate effects of Cu or O and the combined effect of Cu and O

  18. Clean thermal decomposition of tertiary-alkyl metal thiolates to metal sulfides: environmentally-benign, non-polar inks for solution-processed chalcopyrite solar cells

    NASA Astrophysics Data System (ADS)

    Heo, Jungwoo; Kim, Gi-Hwan; Jeong, Jaeki; Yoon, Yung Jin; Seo, Jung Hwa; Walker, Bright; Kim, Jin Young

    2016-11-01

    We report the preparation of Cu2S, In2S3, CuInS2 and Cu(In,Ga)S2 semiconducting films via the spin coating and annealing of soluble tertiary-alkyl thiolate complexes. The thiolate compounds are readily prepared via the reaction of metal bases and tertiary-alkyl thiols. The thiolate complexes are soluble in common organic solvents and can be solution processed by spin coating to yield thin films. Upon thermal annealing in the range of 200–400 °C, the tertiary-alkyl thiolates decompose cleanly to yield volatile dialkyl sulfides and metal sulfide films which are free of organic residue. Analysis of the reaction byproducts strongly suggests that the decomposition proceeds via an SN1 mechanism. The composition of the films can be controlled by adjusting the amount of each metal thiolate used in the precursor solution yielding bandgaps in the range of 1.2 to 3.3 eV. The films form functioning p-n junctions when deposited in contact with CdS films prepared by the same method. Functioning solar cells are observed when such p-n junctions are prepared on transparent conducting substrates and finished by depositing electrodes with appropriate work functions. This method enables the fabrication of metal chalcogenide films on a large scale via a simple and chemically clear process.

  19. CuxS counter electrodes in-situ prepared via the sulfidation of magnetron sputtering Cu film for quantum dot sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Wang, Yuanqiang; Zhang, Qinghong; Li, Yaogang; Wang, Hongzhi

    2016-06-01

    The nanosheet-structured CuxS thin films used as counter electrodes (CEs) for CdS/CdSe quantum dot sensitized solar cells (QDSSCs) have been in situ prepared via the sulfidation of Cu nanoparticles deposited on F-doped SnO2 glass (FTO glass) substrate by magnetron sputtering method. The thickness of the deposited Cu film affects the morphology and thickness of the obtained CuxS films. The CuxS nanosheet films have good adhesion with FTO glass and the surface exhibits uniform morphology. The characteristics of QDSSCs are studied in more detail by photocurrent-voltage performance measurements, incident photon-to-current conversion efficiency (IPCE) and electrochemical impedance spectroscopy (EIS). The CuxS on FTO glass (CuxS/FTO) CEs show much higher power conversion efficiency (PCE) and IPCE than those of the Pt on FTO (Pt/FTO) CE because of their superior carrier mobility and electro-catalytic ability for the polysulfide redox reactions. Based on an optimal CuxS film thickness of 2.7 μm obtained by the sulfidation of the Cu film thickness of 300 nm on FTO, the best photovoltaic performance with PCE of 3.67% (Jsc = 16.47 mA cm-2, Voc = 0.481 V, FF = 0.46) under full one-sun illumination is achieved.

  20. Clean thermal decomposition of tertiary-alkyl metal thiolates to metal sulfides: environmentally-benign, non-polar inks for solution-processed chalcopyrite solar cells

    PubMed Central

    Heo, Jungwoo; Kim, Gi-Hwan; Jeong, Jaeki; Yoon, Yung Jin; Seo, Jung Hwa; Walker, Bright; Kim, Jin Young

    2016-01-01

    We report the preparation of Cu2S, In2S3, CuInS2 and Cu(In,Ga)S2 semiconducting films via the spin coating and annealing of soluble tertiary-alkyl thiolate complexes. The thiolate compounds are readily prepared via the reaction of metal bases and tertiary-alkyl thiols. The thiolate complexes are soluble in common organic solvents and can be solution processed by spin coating to yield thin films. Upon thermal annealing in the range of 200–400 °C, the tertiary-alkyl thiolates decompose cleanly to yield volatile dialkyl sulfides and metal sulfide films which are free of organic residue. Analysis of the reaction byproducts strongly suggests that the decomposition proceeds via an SN1 mechanism. The composition of the films can be controlled by adjusting the amount of each metal thiolate used in the precursor solution yielding bandgaps in the range of 1.2 to 3.3 eV. The films form functioning p-n junctions when deposited in contact with CdS films prepared by the same method. Functioning solar cells are observed when such p-n junctions are prepared on transparent conducting substrates and finished by depositing electrodes with appropriate work functions. This method enables the fabrication of metal chalcogenide films on a large scale via a simple and chemically clear process. PMID:27827402

  1. Clean thermal decomposition of tertiary-alkyl metal thiolates to metal sulfides: environmentally-benign, non-polar inks for solution-processed chalcopyrite solar cells.

    PubMed

    Heo, Jungwoo; Kim, Gi-Hwan; Jeong, Jaeki; Yoon, Yung Jin; Seo, Jung Hwa; Walker, Bright; Kim, Jin Young

    2016-11-09

    We report the preparation of Cu2S, In2S3, CuInS2 and Cu(In,Ga)S2 semiconducting films via the spin coating and annealing of soluble tertiary-alkyl thiolate complexes. The thiolate compounds are readily prepared via the reaction of metal bases and tertiary-alkyl thiols. The thiolate complexes are soluble in common organic solvents and can be solution processed by spin coating to yield thin films. Upon thermal annealing in the range of 200-400 °C, the tertiary-alkyl thiolates decompose cleanly to yield volatile dialkyl sulfides and metal sulfide films which are free of organic residue. Analysis of the reaction byproducts strongly suggests that the decomposition proceeds via an SN1 mechanism. The composition of the films can be controlled by adjusting the amount of each metal thiolate used in the precursor solution yielding bandgaps in the range of 1.2 to 3.3 eV. The films form functioning p-n junctions when deposited in contact with CdS films prepared by the same method. Functioning solar cells are observed when such p-n junctions are prepared on transparent conducting substrates and finished by depositing electrodes with appropriate work functions. This method enables the fabrication of metal chalcogenide films on a large scale via a simple and chemically clear process.

  2. Cadmium Sulfide and Nickel Synergetic Co-catalysts Supported on Graphitic Carbon Nitride for Visible-Light-Driven Photocatalytic Hydrogen Evolution.

    PubMed

    Yue, Xinzheng; Yi, Shasha; Wang, Runwei; Zhang, Zongtao; Qiu, Shilun

    2016-02-29

    Design and preparation of noble-metal-free photocatalysts is of great importance for photocatalytic water splitting harvesting solar energy. Here, we report the high visible-light-driven hydrogen evolution upon the hybrid photocatalyst system consisting of CdS nanocrystals and Ni@NiO nanoparticles grown on the surface of g-C3N4. The hybrid system shows a high H2-production rate of 1258.7 μmol h(-1) g(-1) in the presence of triethanolamine as a sacrificial electron donor under visible light irradiation. The synergetic catalytic mechanism has been studied and the results of photovoltaic and photoluminescence properties show that efficient electron transfer could be achieved from g-C3N4 to CdS nanocrystals and subsequently to Ni@NiO hybrid.

  3. Cadmium Sulfide and Nickel Synergetic Co-catalysts Supported on Graphitic Carbon Nitride for Visible-Light-Driven Photocatalytic Hydrogen Evolution

    NASA Astrophysics Data System (ADS)

    Yue, Xinzheng; Yi, Shasha; Wang, Runwei; Zhang, Zongtao; Qiu, Shilun

    2016-02-01

    Design and preparation of noble-metal-free photocatalysts is of great importance for photocatalytic water splitting harvesting solar energy. Here, we report the high visible-light-driven hydrogen evolution upon the hybrid photocatalyst system consisting of CdS nanocrystals and Ni@NiO nanoparticles grown on the surface of g-C3N4. The hybrid system shows a high H2-production rate of 1258.7 μmol h‑1 g‑1 in the presence of triethanolamine as a sacrificial electron donor under visible light irradiation. The synergetic catalytic mechanism has been studied and the results of photovoltaic and photoluminescence properties show that efficient electron transfer could be achieved from g-C3N4 to CdS nanocrystals and subsequently to Ni@NiO hybrid.

  4. Cadmium Sulfide and Nickel Synergetic Co-catalysts Supported on Graphitic Carbon Nitride for Visible-Light-Driven Photocatalytic Hydrogen Evolution

    PubMed Central

    Yue, Xinzheng; Yi, Shasha; Wang, Runwei; Zhang, Zongtao; Qiu, Shilun

    2016-01-01

    Design and preparation of noble-metal-free photocatalysts is of great importance for photocatalytic water splitting harvesting solar energy. Here, we report the high visible-light-driven hydrogen evolution upon the hybrid photocatalyst system consisting of CdS nanocrystals and Ni@NiO nanoparticles grown on the surface of g-C3N4. The hybrid system shows a high H2-production rate of 1258.7 μmol h−1 g−1 in the presence of triethanolamine as a sacrificial electron donor under visible light irradiation. The synergetic catalytic mechanism has been studied and the results of photovoltaic and photoluminescence properties show that efficient electron transfer could be achieved from g-C3N4 to CdS nanocrystals and subsequently to Ni@NiO hybrid. PMID:26923439

  5. New Thin-Film Solar Cells Compared to Normal Solar Cells

    NASA Image and Video Library

    1966-06-21

    Adolph Spakowski, head of the Photovoltaic Fundamentals Section at the National Aeronautics and Space Administration (NASA) Lewis Research Center, illustrated the difference between conventional silicon solar cells (rear panel) and the new thin-film cells. The larger, flexible thin-film cells in the foreground were evaluated by Lewis energy conversion specialists for possible future space use. The conventional solar cells used on most spacecraft at the time were both delicate and heavy. For example, the Mariner IV spacecraft required 28,000 these solar cells for its flyby of Mars in 1964. NASA Lewis began investigating cadmium sulfide thin-film solar cells in 1961. The thin-film cells were made by heating semiconductor material until it evaporated. The vapor was then condensed onto an electricity-producing film only one-thousandth of an inch thick. The physical flexibility of the new thin-film cells allowed them to be furled, or rolled up, during launch. Spakowski led an 18-month test program at Lewis to investigate the application of cadmium sulfide semiconductors on a light metallized substrate. The new thin-film solar cells were tested in a space simulation chamber at a simulated altitude of 200 miles. Sunlight was recreated by a 5000-watt xenon light. Two dozen cells were exposed to 15 minutes of light followed by 15 minutes of darkness to test their durability in the constantly changing illumination of Earth orbit.

  6. Spectral analysis of the effects of 1.7 MeV electron irradiation on the current transfer characteristic of cadmium telluride solar cells.

    PubMed

    Tian, Jin-Xiu; Zeng, Guang-Gen; He, Xu-Lin; Zhang, Jing-Quan; Wu, Li-Li; Li, Wei; Li, Bing; Wang, Wen-Wu; Feng, Liang-Huan

    2014-04-01

    The effects of device performance of 1.7 MeV electron irradiation on cadmium telluride polycrystalline thin film solar cells with the structure of anti-radiation glass/ITO/ZnO/CdS/CdTe/ZnTe/ZnTe : Cu/Ni have been studied. Light and dark I-V characteristics, dark C-V characteristics, quantum efficiency (QE), admittance spectrum (AS) and other testing methods were used to analyze cells performance such as the open-circuit voltage (Voc), short-circuit current (Isc), fill factor (FF) and conversion efficiency (eta). It was explored to find out the effects of irradiation on the current transfer characteristic of solar cells combined with the dark current density (Jo), diode ideal factor (A), quantum efficiency, carrier concentration and the depletion layer width. The decline in short-circuit current was very large and the efficiency of solar cells decreased obviously after irradiation. Reverse saturation current density increased, which indicates that p-n junction characteristics of solar cells were damaged, and diode ideal factor was almost the same, so current transport mechanism of solar cells has not changed. Quantum efficiency curves proved that the damage of solar cells' p-n junction influenced the collection of photo-generated carriers. Irradiation made carrier concentration reduce to 40.6%. The analyses have shown that. A new defect was induced by electron irradiation, whose position is close to 0.58 eV above the valence band in the forbidden band, and capture cross section is 1.78 x 10(-16) cm2. These results indicate that irradiation influences the generation of photo-generated carriers, increases the risk of the carrier recombination and the reverse dark current, and eventually makes the short-circuit current of solar cells decay.

  7. Preliminary Measurements of Thin Film Solar Cells

    NASA Image and Video Library

    1967-06-21

    George Mazaris, works with an assistant to obtain the preliminary measurements of cadmium sulfide thin-film solar cells being tested in the Space Environmental Chamber at the National Aeronautics and Space Administration (NASA) Lewis Research Center. Lewis’ Photovoltaic Fundamentals Section was investigating thin-film alternatives to the standard rigid and fragile solar cells. The cadmium sulfide semiconductors were placed in a light, metallized substrate that could be rolled or furled during launch. The main advantage of the thin-film solar cells was their reduced weight. Lewis researchers, however, were still working on improving the performance of the semiconductor. The new thin-film solar cells were tested in a space simulation chamber in the CW-6 test cell in the Engine Research Building. The chamber created a simulated altitude of 200 miles. Sunlight was simulated by a 5000-watt xenon light. Some two dozen cells were exposed to 15 minutes of light followed by 15 minutes of darkness to test their durability in the constantly changing illumination of Earth orbit. This photograph was taken for use in a NASA recruiting publication.

  8. Errors in short circuit measurements due to spectral mismatch between sunlight and solar simulators

    NASA Technical Reports Server (NTRS)

    Curtis, H. B.

    1976-01-01

    Errors in short circuit current measurement were calculated for a variety of spectral mismatch conditions. The differences in spectral irradiance between terrestrial sunlight and three types of solar simulator were studied, as well as the differences in spectral response between three types of reference solar cells and various test cells. The simulators considered were a short arc xenon lamp AMO sunlight simulator, an ordinary quartz halogen lamp, and an ELH-type quartz halogen lamp. Three types of solar cells studied were a silicon cell, a cadmium sulfide cell and a gallium arsenide cell.

  9. a Study of Deep Levels in COPPER-INDIUM-SELENIUM(2) by Current-Voltage Capacitance-Voltage and Capacitance Transient Measurements on Cadmium-Sulfide -SELENIUM(2)

    NASA Astrophysics Data System (ADS)

    Christoforou, Nicholas

    A study was made of the deep levels in CuInSe _ 2 thin films by Current-Voltage, Capacitance-Voltage, Capacitance-Temperature, and Capacitance Transient measurements on CdS/CuInSe_ 2 solar cells. To accomplish this study, a semi -automated system for Current-Voltage (I-V), Capacitance -Voltage (C-V), and Deep Level Transient Spectroscopy (DLTS) has been developed for the study of semiconductor devices. I -V, C-V, and DLTS measurements can be taken over a wide temperature range, from 100 K up to 450 K. Software for processing the data obtained has also been developed. This thesis presents the first reported successful measurements of deep levels in CuInSe_ 2 by DLTS measurements. The results indicate the presence in the p-type CuInSe_ 2 films of a majority-carrier (hole) trap located 0.70 eV above the valence band edge and a minority-carrier (electron) trap located 0.35 eV below the conduction band edge. Simulation studies show that the width and shape of the DLTS spectra for the hole trap can be explained only by assuming that the traps are distributed in energy around 0.70 eV. Our results are consistent with traps distributed from 0.65 to 0.75 eV, but it is not possible to determine uniquely the exact distribution. The electron trap at 0.35 eV does is not distributed in energy. There is strong evidence from the C-V, C-T, and I-V measurements, and indirectly from the DLTS measurements, that there is a large hole trap concentration in the CuInSe _ 2 layer close to the interface with the CdS. These interface states have a concentration of approximately 5 times 10 ^{15} cm^{ -3}, compared to a doping density in the CuInSe _ 2 layer of 1 times 10^{15} cm ^{-3}, a hole trap concentration of 5 times 10^{14 } cm^{-3}, and an electron trap concentration of 0.5 times 10^{14} cm ^{-3}. The I-V measurements are consistent with charge transport via an interface recombination/tunneling mechanism, where the tunneling is assisted by the interface states.

  10. One-step fabrication of copper sulfide nanoparticles decorated on graphene sheets as highly stable and efficient counter electrode for CdS-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Hessein, Amr; Wang, Feiju; Masai, Hirokazu; Matsuda, Kazunari; Abd El-Moneim, Ahmed

    2016-11-01

    Quantum-dot-sensitized solar cells (QDSSCs) are thin-film photovoltaics and highly promising as next-generation solar cells owing to their high theoretical efficiency, easy fabrication process, and low production cost. However, the practical photoconversion efficiencies (PCEs) of QDSSCs are still far below the theoretically estimated value owing to the lack of an applicable design of the materials and electrodes. In this work, we developed a highly stable and efficient counter electrode (CE) from copper sulfide nanocrystals and reduced graphene oxide (Cu x S@RGO) for QDSSC applications. The Cu x S@RGO electrocatalyst was successfully prepared by a facile one-pot hydrothermal method, then directly applied to a fluorine-doped tin oxide (FTO)-coated glass substrate by the simple drop-casting technique. Owing to the synergistic effect between Cu x S nanocrystals and conductive RGO sheets, the Cu x S@RGO CE showed high electrocatalytic activity for polysulfide electrolyte reduction. A CdS QDSSC based on the Cu x S@RGO CE yielded a high and reproducible PCE of 2.36%, exceeding those of 1.57 and 1.33% obtained with the commonly used Cu2S/brass and Pt CEs, respectively. Moreover, the QDSSC with the Cu x S@RGO CE showed excellent photostability in a light-soaking test without any obvious decay in the photocurrent, whereas the cell based on the Cu2S/brass CE was severely degraded.

  11. Lead antimony sulfide (Pb5Sb8S17) solid-state quantum dot-sensitized solar cells with an efficiency of over 4%

    NASA Astrophysics Data System (ADS)

    Chang, Yi-Cheng; Suriyawong, Nipapon; Aragaw, Belete Asefa; Shi, Jen-Bin; Chen, Peter; Lee, Ming-Way

    2016-04-01

    Lead antimony sulfides are rare in nature and relatively unexplored ternary semiconductors. This work investigates the photovoltaic performance of Pb-Sb-S quantum dot-sensitized solar cells (QDSCs). Pb5Sb8S17 nanoparticles are grown on mesoporous TiO2 electrodes using the successive ionic layer adsorption reaction process. The synthesized Pb5Sb8S17 nanoparticles exhibit two attractive features for a good solar absorber material: a high optical absorption coefficient and a near optimal energy gap. Solid-state QDSCs are fabricated from the synthesized Pb5Sb8S17 nanoparticles using Spiro-OMeTAD as the hole-transporting material. The best cell yields a short-circuit current density Jsc of 11.92 mA cm-2, an open-circuit voltage Voc of 0.48 V, a fill factor FF of 30.7% and a power conversion efficiency (PCE) of 1.76% under 1sun. The external quantum efficiency (EQE) spectrum covers a spectral range of 350-800 nm with a maximal EQE = 65% at λ = 450 nm. At the reduced light intensity of 10% sun, the PCE increases to 4.14% with Jsc = 2.0 mA cm-2 (which could be normalized to 20 mA cm-2 under 1 sun). This PCE is 65% higher than the best previous result. The respectable PCE and Jsc indicate that Pb5Sb8S17 could be a potential candidate for a solar absorber material.

  12. Nanocrystal Photovoltaics: The Case of Copper Sulfide-Cadmium Sulfide

    NASA Astrophysics Data System (ADS)

    Rivest, Jessica Louis Baker

    In this dissertation, fine control over the morphology and composition of a nanostructured semiconductor thin film is demonstrated at a degree not previously possible. While such control is beneficial in a variety of optical and electrical devices, this research was performed from the perspective of photovoltaics. A new architecture is presented for low cost and high conversion efficiency photovoltaics, utilizing self-assembled nanocrystals. A method is introduced for vertically aligning nanorods using a controlled-evaporation self-assembly technique, enabling the uniform alignment of nanorods on a square-centimeter substrate. Such meso-scale assembly and optimization required the development of a morphology quantification technique. The technique presented here utilizes grazing incidence x-ray diffraction to assemble a quantitative pole figure, or nanorod orientation histogram, and can be used with any thin film. After nanorod assembly, an asymmetric electrical junction (required for photovoltaic operation) is achieved in each rod using a cation exchange technique, which can be performed reliably and reversibly on-chip. This results in a film comprising a massively parallel array of single-crystal nanodiodes. Electrical measurements of these films show rectified behavior and reveal a photocurrent upon illumination of the aligned and cation-exchanged films. Finally, the stability of the Cu 2S phase is investigated as a function of nanocrystal size. The low chalcocite to high chalcocite solid-solid crystallographic phase transition is found to occur at temperatures depressed 60 Kelvin below the bulk phase transition temperature. The research summarized in this dissertation describes a set of synthetic and analytical techniques that enable nanoscopic control of morphology and composition in device-scale semiconductor thin films. Such control may be leveraged to precisely manipulate the flow of charge carriers in optoelectronic devices. Due to the simple wet chemical processes employed in the fabrication of these devices, the techniques presented suggest the possibility of very low cost. This work provides a proof-of-concept for a next-generation photovoltaic device architecture, and serves as a set of guidelines for achieving the desired crystallographic phase, crystallographic orientation, and compositional patterning desired in a nanostructured semiconductor thin film.

  13. Removal of insoluble heavy metal sulfides from water.

    PubMed

    Banfalvi, Gaspar

    2006-05-01

    The necessity of heavy metal removal from wastewater has led to increasing interest in absorbents. We have developed a new approach to obtain high metal adsorption capacity by precipitating metal sulfides with sodium sulfide on the surface of bentonite and adhere them to the absorbent. This method allowed to remove approximately 90% of cadmium as CdS from 10(-4)-10(-6) M CdCl2 solutions. Additional reactions are related to the removal of excess sodium sulfide by the release of hydrogen sulfide and oxidation to sulfur using carbogen gas (5% CO2, 95% O2) followed by aeration.

  14. High-efficiency cadmium-free Cu(In,Ga)Se{sub 2} thin-film solar cells with chemically deposited ZnS buffer layers

    SciTech Connect

    Nakada, Tokio; Furumi, Keisuke; Kunioka, Akio

    1999-10-01

    Cadmium-free Cu(In,Ga)Se{sub 2} (CIGS) thin-film solar cells with a MgF{sub 2}/ZnO:Al/CBD-ZnS/CIGS/Mo/SLG structure have been fabricated using chemical bath deposition (CBD)-ZnS buffer layers and high-quality CIGS absorber layers grown using molecular beam epitaxy (MBE) system. The use of CBD-ZnS, which is a wider band gap material than CBD-CdS, improved the quantum efficiency of fabricated cells at short wavelengths, leading to an increase in the short-circuit current. The best cell at present yielded an active area efficiency of 16.9% which is the highest value reported previously for Cd-free CIGS thin-film solar cells. The as-fabricated solar cells exhibited a reversible light-soaking effect under AM 1.5, 100 mW/cm{sup 2} illumination. This paper also presents a discussion of the issues relating to the use of the CBD-ZnS buffer material for improving device performance.

  15. Optimized approach to retrieve information on the tropospheric and stratospheric carbonyl sulfide (OCS) vertical distributions above Jungfraujoch from high-resolution FTIR solar spectra.

    NASA Astrophysics Data System (ADS)

    Lejeune, Bernard; Mahieu, Emmanuel; Servais, Christian; Duchatelet, Pierre; Demoulin, Philippe

    2010-05-01

    Carbonyl sulfide (OCS), which is produced in the troposphere from both biogenic and anthropogenic sources, is the most abundant gaseous sulfur species in the unpolluted atmosphere. Due to its low chemical reactivity and water solubility, a significant fraction of OCS is able to reach the stratosphere where it is converted to SO2 and ultimately to H2SO4 aerosols (Junge layer). These aerosols have the potential to amplify stratospheric ozone destruction on a global scale and may influence Earth's radiation budget and climate through increasing solar scattering. The transport of OCS from troposphere to stratosphere is thought to be the primary mechanism by which the Junge layer is sustained during nonvolcanic periods. Because of this, long-term trends in atmospheric OCS concentration, not only in the troposphere but also in the stratosphere, are of great interest. A new approach has been developed and optimized to retrieve atmospheric abundance of OCS from high-resolution ground-based infrared solar spectra by using the SFIT-2 (v3.91) algorithm, including a new model for solar lines simulation (solar lines often produce significant interferences in the OCS microwindows). The strongest lines of the ν3 fundamental band of OCS at 2062 cm-1 have been systematically evaluated with objective criteria to select a new set of microwindows, assuming the HITRAN 2004 spectroscopic parameters with an increase in the OCS line intensities of the ν3band main isotopologue 16O12C32S by 15.79% as compared to HITRAN 2000 (Rothman et al., 2008, and references therein). Two regularization schemes have further been compared (deducted from ATMOS and ACE-FTS measurements or based on a Tikhonov approach), in order to select the one which optimizes the information content while minimizing the error budget. The selected approach has allowed us to determine updated OCS long-term trend from 1988 to 2009 in both the troposphere and the stratosphere, using spectra recorded on a regular basis with

  16. Biosorption of lead, copper and cadmium using the extracellular polysaccharides (EPS) of Bacillus sp., from solar salterns.

    PubMed

    Shameer, Syed

    2016-12-01

    Extracellular Polysaccharides (EPS) from both prokaryotes and eukaryotes have a great deal of research interest as they protect the producer from different stresses including antibiotics, ionic stress, desiccation and assist in bio-film formation, pathogenesis, adhesion, etc. In this study haloalkaliphilic Bacillus sp., known to cope with osmophilic stress, was selected and screened for EPS production. The EPS were isolated, partially purified and chemical characteristics were documented using liquid FT-IR followed by assessment of heavy metal biosorption (lead, copper and cadmium) using Atomic Absorption Spectroscopy (AAS). The EPS extracted from three isolates B. licheniformis NSPA5, B. cereus NSPA8 and B. subtilis NSPA13 showed maximum biosorption of Lead followed by Copper and Cadmium. Of the tested isolates, the EPS from isolate B. cereus NSPA8 showed maximum (90 %) biosorption of the lead.

  17. Mineral of the month: cadmium

    USGS Publications Warehouse

    Klimasauskas, Edward

    2005-01-01

    Cadmium, which was once used almost exclusively for pigments, now has many diverse applications. Cadmium’s low melting point, excellent electrical conductivity and resistance to corrosion make it valuable for many products including batteries, electroplated coatings, stabilizers for plastics, solar cells and nonferrous alloys. Today’s cadmium is primarily used in rechargeable batteries, accounting for about 78 percent of consumption in 2004. In 2000, an estimated 3.5 billion consumer batteries were sold in the United States, of which almost 10 percent were nickel-cadmium batteries.

  18. Cadmium toxicity

    PubMed Central

    Wan, Lichuan; Zhang, Haiyan

    2012-01-01

    Cadmium is a well-known environmental pollutant with distinctly toxic effects on plants. It can displace certain essential metals from a wealth of metalloproteins, and thus disturb many normal physiological processes and cause severe developmental aberrant. The harmful effects of cadmium stress include, but are not limited to: reactive oxygen species overproduction, higher lipid hydroperoxide contents, and chloroplast structure change, which may lead to cell death. Plants have developed diverse mechanisms to alleviate environmental cadmium stress, e.g., cadmium pump and transporting cadmium into the leaf vacuoles. This mini-review focuses on the current research into understanding the cellular mechanisms of cadmium toxicity on cytoskeleton, vesicular trafficking and cell wall formation in plants. PMID:22499203

  19. Room-temperature preparation of trisilver-copper-sulfide/polymer based heterojunction thin film for solar cell application

    NASA Astrophysics Data System (ADS)

    Lei, Yan; Yang, Xiaogang; Gu, Longyan; Jia, Huimin; Ge, Suxiang; Xiao, Pin; Fan, Xiaoli; Zheng, Zhi

    2015-04-01

    Solar cells devices based on inorganic/polymer heterojunction can be a possible solution to harvest solar energy and convert to electric energy with high efficiency through a cost-effective fabrication. The solution-process method can be easily used to produce large area devices. Moreover, due to the intrinsic different charge separation, diffusion or recombination in various semiconductors, the interfaces between each component may strongly influence the inorganic/polymer heterojunction performance. Here we prepared a n-type Ag3CuS2 (Eg = 1.25 eV) nanostructured film through a room-temperature element reaction process, which was confirmed as direct bandgap semiconductor through density function theory simulation. This Ag3CuS2 film was spin-coated with an organic semiconducting poly(3-hexythiophene) (P3HT) or polythieno[3,4-b]-thiophene-co-benzodithiophene (PTB7) film, which formed an inorganic/polymer heterojunction. After constructing it to a solar cell device, the power conversion efficiencies of 0.79% and 0.31% were achieved with simulated solar illumination on Ag3CuS2/P3HT and Ag3CuS2/PTB7, respectively. A possible mechanism was discussed and we showed the charge separation at interface of inorganic and polymer semiconductors played an important role.

  20. Dip coated nanocrystalline CdZnS thin films for solar cell application

    NASA Astrophysics Data System (ADS)

    Dongre, J. K.; Chaturvedi, Mahim; Patil, Yuvraj; Sharma, Sandhya; Jain, U. K.

    2015-07-01

    Nanocrystalline cadmium sulfide (CdS) and zinc cadmium sulfide (ZnCdS) thin films have been grown via simple and low cost dip coating technique. The prepared films are characterized by X-ray diffraction (XRD), atomic force microscopic (AFM) and UV-VIS spectrophotometer techniques to reveal their structural, morphological and optical properties. XRD shows that both samples grown have zinc blende structure. The grain size is calculated as 6.2 and 8 nm using Scherrer's formula. The band gap value of CdS and CdZnS film is estimated to be 2.58 and 2.69 eV respectively by UV-vis spectroscopy. Photoelectrochemical (PEC) investigations are carried out using cell configuration as n-CdZnS/(1M NaOH + 1M Na2S + 1M S)/C. The photovoltaic output characteristic is used to calculate fill-factor (FF) and solar conversion efficiency (η).

  1. Cadmium Alternatives

    DTIC Science & Technology

    2012-08-01

    including cadmium! Cadmium Replacements (With MIL-DTL-38999 Designations) Zn/Ni (Class Z) Per ASTM B 841, type D (black) Electroless Nickel plus... Electroless nickel / PTFE (Durmalon®) Electroplated Aluminum (Alumiplate®) Electroplated tin-zinc (SnZn) Control: cadmium with hexavalent chromate... electroless nickel / PTFE performed well Electroplated aluminum performed did not perform well on connectors Electroplated aluminum did not

  2. Sulfidation of Cadmium at the Nanoscale

    SciTech Connect

    Cabot, Andreu; Smith, Rachel; Yin, Yadong; Zheng, Haimei; Reinhard, Bjorn; Liu, Haitao; Alivisatos, A. Paul

    2008-05-22

    We investigate the evolution of structures that result when spherical Cd nanoparticles of a few hundred nanometers in diameter react with dissolved molecular sulfur species in solution to form hollow CdS. Over a wide range of temperatures and concentrations, we find that rapid Cd diffusion through the growing CdS shell localizes the reaction front at the outermost CdS/S interface, leading to hollow particles when all the Cd is consumed. When we examine partially reacted particles, we find that this system differs significantly from others in which the nanoscale Kirkendall effect has been used to create hollow particles. In previously reported systems, partial reaction creates a hollow particle with a spherically symmetric metal core connected to the outer shell by filaments. In contrast, here we obtain a lower symmetry structure, in which the unreacted metal core and the coalesced vacancies separate into two distinct spherical caps, minimizing the metal/void interface. This pattern of void coalescence is likely to occur in situations where the metal/vacancy self-diffusivities in the core are greater than the diffusivity of the cations through the shell.

  3. Investigation of photoresponse in cadmium sulfide nanoparticles

    NASA Astrophysics Data System (ADS)

    Mishra, Sheo K.; Tripathi, Akhilesh; Srivastava, Rajneesh K.; Dubey, K. C.; Shukla, R. K.

    2015-06-01

    In this work, we report on the photo-response of CdS nanoparticles prepared by simple solid state reaction method. The X-ray diffraction (XRD) study has confirmed the formation of cubical zinc blende (c) phase. In the photo-response study, voltage dependence of photocurrent and darkcurrent as well as temporal rise and decay of photocurrent of CdS nanoparticles have been investigated. The photo-response of prepared sample has been measured under visible illumination using thick film of powder with out any binder. The photocurrent (Ipc) and darkcurrent (Idc) follow power law with applied voltage i.e. I α Vr. The rise and decay of photocurrent show negative photoconductivity.

  4. Investigation of photoresponse in cadmium sulfide nanoparticles

    SciTech Connect

    Mishra, Sheo K. E-mail: dr.sheokmishra@gmail.com; Tripathi, Akhilesh; Shukla, R. K.; Srivastava, Rajneesh K.; Dubey, K. C.

    2015-06-24

    In this work, we report on the photo-response of CdS nanoparticles prepared by simple solid state reaction method. The X-ray diffraction (XRD) study has confirmed the formation of cubical zinc blende (c) phase. In the photo-response study, voltage dependence of photocurrent and darkcurrent as well as temporal rise and decay of photocurrent of CdS nanoparticles have been investigated. The photo-response of prepared sample has been measured under visible illumination using thick film of powder with out any binder. The photocurrent (I{sub pc}) and darkcurrent (I{sub dc}) follow power law with applied voltage i.e. I α V{sup r}. The rise and decay of photocurrent show negative photoconductivity.

  5. Cadmium zinc sulfide by solution growth

    SciTech Connect

    Chen, W.S.

    1992-05-12

    This patent describes a photoelectric cell. It comprises a thin film of CdZnS that forms a continuous coating free of pin holes and has a thickness that is sufficiently thin to provide at least 70% transmission of radiation having a wavelength 400 nm.

  6. Methods for improving solar cell open circuit voltage

    DOEpatents

    Jordan, John F.; Singh, Vijay P.

    1979-01-01

    A method for producing a solar cell having an increased open circuit voltage. A layer of cadmium sulfide (CdS) produced by a chemical spray technique and having residual chlorides is exposed to a flow of hydrogen sulfide (H.sub.2 S) heated to a temperature of 400.degree.-600.degree. C. The residual chlorides are reduced and any remaining CdCl.sub.2 is converted to CdS. A heterojunction is formed over the CdS and electrodes are formed. Application of chromium as the positive electrode results in a further increase in the open circuit voltage available from the H.sub.2 S-treated solar cell.

  7. Thin film cadmium telluride, zinc telluride, and mercury zinc telluride solar cells. Final subcontract report, 1 July 1988--31 December 1991

    SciTech Connect

    Chu, T.L.

    1992-04-01

    This report describes research to demonstrate (1) thin film cadmium telluride solar cells with a quantum efficiency of 75% or higher at 0. 44 {mu}m and a photovoltaic efficiency of 11.5% or greater, and (2) thin film zinc telluride and mercury zinc telluride solar cells with a transparency to sub-band-gap radiation of 65% and a photovoltaic conversion efficiency of 5% and 8%, respectively. Work was directed at (1) depositing transparent conducting semiconductor films by solution growth and metal-organic chemical vapor deposition (MOCVD) technique, (2) depositing CdTe films by close-spaced sublimation (CSS) and MOCVD techniques, (3) preparing and evaluating thin film CdTe solar cells, and (4) preparing and characterizing thin film ZnTe, CD{sub 1-x}Zn{sub 1-x}Te, and Hg{sub 1-x}Zn{sub x}Te solar cells. The deposition of CdS films from aqueous solutions was investigated in detail, and their crystallographic, optical, and electrical properties were characterized. CdTe films were deposited from DMCd and DIPTe at 400{degrees}C using TEGa and AsH{sub 3} as dopants. CdTe films deposited by CSS had significantly better microstructures than those deposited by MOCVD. Deep energy states in CdTe films deposited by CSS and MOCVD were investigated. Thin films of ZnTe, Cd{sub 1- x}Zn{sub x}Te, and Hg{sub 1-x}Zn{sub x}Te were deposited by MOCVD, and their crystallographic, optical, and electrical properties were characterized. 67 refs.

  8. Routes to copper zinc tin sulfide Cu2ZnSnS4 a potential material for solar cells.

    PubMed

    Ramasamy, Karthik; Malik, Mohammad A; O'Brien, Paul

    2012-06-11

    Power generation through photovoltaics (PV) has been growing at an average rate of 40% per year over the last decade; but has largely been fuelled by conventional Si-based technologies. Such cells involve expensive processing and many alternatives use either toxic, less-abundant and or expensive elements. Kesterite Cu(2)ZnSnS(4) (CZTS) has been identified as a solar energy material composed of both less toxic and more available elements. Power conversion efficiencies of 8.4% (vacuum processing) and 10.1% (non-vacuum processing) from cells constructed using CZTS have been achieved to date. In this article, we review various deposition methods for CZTS thin films and the synthesis of CZTS nanoparticles. Studies of direct relevance to solar cell applications are emphasised and characteristic properties are collated.

  9. Chemical Bath Deposited Zinc Sulfide Buffer Layers for Copper Indium Gallium Sulfur-selenide Solar Cells and Device Analysis

    SciTech Connect

    Kundu, Sambhu N.; Olsen, Larry C.

    2005-01-03

    Cd free CIGSS thin film solar cell structures with a MgF2/TCO/CGD-ZnS/CIGSS/Mo/SLG structure have been fabricated using chemical bath deposited (CBD)-ZnS buffer layers and high quality CIGSS absorber layers supplied from Shell Solar Industries. The use of CBD-ZnS, which is a higher band gap materials than CdS, improved the quantum efficiency of fabricated cells at lower wavelengths, leading to an increase in short circuit current. The best cell to date yielded an active area (0.43 cm2) efficiency of 13.3%. This paper also presents a discussion of the issues relating to the use of the CBD-ZnS buffer materials for improving device performance.

  10. Inorganic phosphate accumulation and cadmium detoxification in Klebsiella aerogenes NCTC 418 growing in continuous culture

    SciTech Connect

    Aiking, H.; Stijnman, A.; van Garderen, C.; van Heerikhuizen, H.; van Riet, J.

    1984-02-01

    Klebsiella aerogenes NCTC-418, growing in the presence of cadmium under glucose-, sulfate-, or phosphate-limited conditions in continuous culture, exhibits two different cadmium detoxifying mechanisms. In addition to sulfide formation, increased accumulation of P/sub i/ is demonstrated as a novel mechanism. Intracellular cadmium is always quantitatively counterbalanced by a concerted increase in both inorganic sulfide and P/sub i/ contents of the cells. This led to the conclusion that production of sulfide and accumulation of P/sub i/ are detoxification mechanisms present in K. aerogenes but that their relative importance is crucially dependent on the strain and the growth conditions employed.

  11. Wurtzite copper-zinc-tin sulfide as a superior counter electrode material for dye-sensitized solar cells

    PubMed Central

    2013-01-01

    Wurtzite and kesterite Cu2ZnSnS4 (CZTS) nanocrystals were employed as counter electrode (CE) materials for dye-sensitized solar cells (DSSCs). Compared to kesterite CZTS, the wurtzite CZTS exhibited higher electrocatalytic activity for catalyzing reduction of iodide electrolyte and better conductivity. Accordingly, the DSSC with wurtzite CZTS CE generated higher power conversion efficiency (6.89%) than that of Pt (6.23%) and kesterite CZTS (4.89%) CEs. PMID:24191954

  12. Selenium sulfide

    Integrated Risk Information System (IRIS)

    Selenium sulfide ; CASRN 7446 - 34 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic

  13. Carbonyl sulfide

    Integrated Risk Information System (IRIS)

    Carbonyl sulfide ; CASRN 463 - 58 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic

  14. Hydrogen sulfide

    Integrated Risk Information System (IRIS)

    EPA / 635 / R - 03 / 005 www.epa.gov / iris TOXICOLOGICAL REVIEW OF HYDROGEN SULFIDE ( CAS No . 7783 - 06 - 4 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) June 2003 U.S . Environmental Protection Agency Washington , DC DISCLAIMER This document has been

  15. In-situ growth of antimony sulfide in carbon nanoparticle matrix: Enhanced electrocatalytic activity as counter electrode in dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Sun, Panpan; Zhang, Ming; Ai, Changzhi; Wu, Zhixin; Lu, Shuang; Zhang, Xintong; Huang, Niu; Sun, Yihua; Sun, Xiaohua

    2016-07-01

    Considering the undesirable electrocatalytic activity toward I-/I3- redox system of prinstine antimony sulfide (Sb2S3) fabricated with the existing conditions, a mesoporous carbon nanoparticle film (CNP) is introduced here for in-situ growth of Sb2S3 to construct a Sb2S3@CNP hybrid catalyst. Based on a Sb-thiourea precursor solution, in-situ growth of Sb2S3 can be achieved via solution deposition (denoted as Sb2S3@CNP-S) as well as atmospheric pressure thermal evaporation (denoted as Sb2S3@CNP-T) in CNP matrix. Structural characterizations indicate that Sb2S3 particles have well dispersed in the pores of CNP matrix. Because of the introduction of porous and conductive CNP matrix to support Sb2S3, the hybrid catalyst exhibits lower charge transfer resistance at the catalyst/electrolyte interface and higher electrocatalytic activity. When used as counter electrode (CE) for dye-sensitized solar cells (DSSCs), devices using Sb2S3@CNP hybrid catalyst as CE produce fill factor of 67.6% and 66.3%, which is significantly higher than that using pristine Sb2S3 fabricated in our previous work (52.8%). Finally, the corresponding power conversion efficiencies reach 6.69% (Sb2S3@CNP-S) and 6.24% (Sb2S3@CNP-T), respectively, which are comparable to that using Pt CE measured under the same conditions (6.74%).

  16. The Determination of Hydrogen Sulfide in Stack Gases, Iodometric Titration After Sulfite Removal.

    ERIC Educational Resources Information Center

    Robles, E. G.

    The determination of hydrogen sulfide in effluents from coal-fired furnaces and incinerators is complicated by the presence of sulfur oxides (which form acids). Organic compounds also may interfere with or prevent the formation of the cadmium sulfide precipitate or give false positive results because of reaction with iodine. The report presents a…

  17. The Determination of Hydrogen Sulfide in Stack Gases, Iodometric Titration After Sulfite Removal.

    ERIC Educational Resources Information Center

    Robles, E. G.

    The determination of hydrogen sulfide in effluents from coal-fired furnaces and incinerators is complicated by the presence of sulfur oxides (which form acids). Organic compounds also may interfere with or prevent the formation of the cadmium sulfide precipitate or give false positive results because of reaction with iodine. The report presents a…

  18. Synthesis of Bi{sub 2}S{sub 3} quantum dots for sensitized solar cells by reverse SILAR

    SciTech Connect

    Singh, Navjot; Sharma, J.; Tripathi, S. K. E-mail: surya-tr@yahoo.com

    2016-05-06

    Quantum Dot Sensitized Solar cells (QDSSC) have great potential to replace silicon-based solar cells. Quantum dots of various materials and sizes could be used to convert most of the visible light into the electrical current. This paper put emphasis on the synthesis of Bismuth Sulphide quantum dots and selectivity of the anionic precursor by Successive Ionic Layer Adsorption Reaction (SILAR). Bismuth Sulfide (Bi{sub 2}S{sub 3}) (group V – Vi semiconductor) is strong contestant for cadmium free solar cells due to its optimum band gap for light harvesting. Optical, structural and electrical measurements are reported and discussed. Problem regarding the choice of precursor for anion extraction is discussed. Band gap of the synthesized quantum dots is 1.2 eV which does not match with the required energy band gap of bismuth sulfide that is 1.7 eV.

  19. A Photoelectrochemical Solar Cell Consisting of a Cadmium Sulfide Photoanode and a Ruthenium-2,2'-Bipyridine Redox Shuttle in a Non-aqueous Electrolyte.

    PubMed

    Kageshima, Yosuke; Kumagai, Hiromu; Minegishi, Tsutomu; Kubota, Jun; Domen, Kazunari

    2015-06-26

    A photoelectrochemical (PEC) cell consisting of an n-type CdS single-crystal electrode and a Pt counter electrode with the ruthenium-2,2'-bipyridine complex [Ru(bpy)3](2+/3+) as the redox shuttle in a non-aqueous electrolyte was studied to obtain a higher open-circuit voltage (V(OC)) than the onset voltage for water splitting. A V(OC) of 1.48 V and a short-circuit current (I(SC)) of 3.88 mA cm(-2) were obtained under irradiation by a 300 W Xe lamp with 420-800 nm visible light. This relatively high voltage was presumably due to the difference between the Fermi level of photo-irradiated n-type CdS and the redox potential of the Ru complex at the Pt electrode. The smooth redox reaction of the Ru complex with one-electron transfer was thought to have contributed to the high V(OC) and I(SC). The obtained V(OC) was more than the onset voltage of water electrolysis for hydrogen and oxygen generation, suggesting prospects for application in water electrolysis.

  20. Labile sulfide and sulfite in phytochelatin complexes

    SciTech Connect

    Eannetta, N.T.; Steffens, J.C. )

    1989-04-01

    Heavy metals such as cadmium induce tomato cell cultures to synthesize the metal binding polypeptides ({gamma}-Glu-Cys){sub 3} and ({gamma}-Glu-Cys){sub 4}-Gly (phytochelatins). Tomato cells selected for growth on normally lethal concentrations of CdCl{sub 2} synthesize higher quantities of these polypeptides. Cd{sup r} cells are not cross-resistant to other heavy metals, and recent work suggests that metal detoxification by these peptides may be Cd-specific. The occurrence of labile sulfur as a component of the metal complex raises questions concerning possible functions of phytochelatins besides that of Cd binding. The presence of acid-labile sulfide ion in phytochelatin complexes has been reported by several groups. We report the additional finding that labile sulfite is also present in these complexes and in higher amounts than sulfide. Sulfide and sulfite are both released from the metal binding complex by acidification or by treatment with EDTA.

  1. A Genome-Wide Screen of Genes Involved in Cadmium Tolerance in Schizosaccharomyces pombe

    PubMed Central

    Kennedy, Patrick J.; Vashisht, Ajay A.; Hoe, Kwang-Lae; Kim, Dong-Uk; Park, Han-Oh; Hayles, Jacqueline; Russell, Paul

    2008-01-01

    Cadmium is a worldwide environmental toxicant responsible for a range of human diseases including cancer. Cellular injury from cadmium is minimized by stress-responsive detoxification mechanisms. We explored the genetic requirements for cadmium tolerance by individually screening mutants from the fission yeast (Schizosaccharomyces pombe) haploid deletion collection for inhibited growth on agar growth media containing cadmium. Cadmium-sensitive mutants were further tested for sensitivity to oxidative stress (hydrogen peroxide) and osmotic stress (potassium chloride). Of 2649 mutants screened, 237 were sensitive to cadmium, of which 168 were cadmium specific. Most were previously unknown to be involved in cadmium tolerance. The 237 genes represent a number of pathways including sulfate assimilation, phytochelatin synthesis and transport, ubiquinone (Coenzyme Q10) biosynthesis, stress signaling, cell wall biosynthesis and cell morphology, gene expression and chromatin remodeling, vacuole function, and intracellular transport of macromolecules. The ubiquinone biosynthesis mutants are acutely sensitive to cadmium but only mildly sensitive to hydrogen peroxide, indicating that Coenzyme Q10 plays a larger role in cadmium tolerance than just as an antioxidant. These and several other mutants turn yellow when exposed to cadmium, suggesting cadmium sulfide accumulation. This phenotype can potentially be used as a biomarker for cadmium. There is remarkably little overlap with a comparable screen of the Saccharomyces cerevisiae haploid deletion collection, indicating that the two distantly related yeasts utilize significantly different strategies for coping with cadmium stress. These strategies and their relation to cadmium detoxification in humans are discussed. PMID:18684775

  2. A genome-wide screen of genes involved in cadmium tolerance in Schizosaccharomyces pombe.

    PubMed

    Kennedy, Patrick J; Vashisht, Ajay A; Hoe, Kwang-Lae; Kim, Dong-Uk; Park, Han-Oh; Hayles, Jacqueline; Russell, Paul

    2008-11-01

    Cadmium is a worldwide environmental toxicant responsible for a range of human diseases including cancer. Cellular injury from cadmium is minimized by stress-responsive detoxification mechanisms. We explored the genetic requirements for cadmium tolerance by individually screening mutants from the fission yeast (Schizosaccharomyces pombe) haploid deletion collection for inhibited growth on agar growth media containing cadmium. Cadmium-sensitive mutants were further tested for sensitivity to oxidative stress (hydrogen peroxide) and osmotic stress (potassium chloride). Of 2649 mutants screened, 237 were sensitive to cadmium, of which 168 were cadmium specific. Most were previously unknown to be involved in cadmium tolerance. The 237 genes represent a number of pathways including sulfate assimilation, phytochelatin synthesis and transport, ubiquinone (Coenzyme Q10) biosynthesis, stress signaling, cell wall biosynthesis and cell morphology, gene expression and chromatin remodeling, vacuole function, and intracellular transport of macromolecules. The ubiquinone biosynthesis mutants are acutely sensitive to cadmium but only mildly sensitive to hydrogen peroxide, indicating that Coenzyme Q10 plays a larger role in cadmium tolerance than just as an antioxidant. These and several other mutants turn yellow when exposed to cadmium, suggesting cadmium sulfide accumulation. This phenotype can potentially be used as a biomarker for cadmium. There is remarkably little overlap with a comparable screen of the Saccharomyces cerevisiae haploid deletion collection, indicating that the two distantly related yeasts utilize significantly different strategies for coping with cadmium stress. These strategies and their relation to cadmium detoxification in humans are discussed.

  3. Precipitation of cadmium by Clostridium thermoaceticum.

    PubMed Central

    Cunningham, D P; Lundie, L L

    1993-01-01

    Cadmium at an initial concentration of 1 mM was completely precipitated by cultures of Clostridium thermoaceticum in complex medium. The precipitation was energy dependent and required cysteine, although cysteine alone did not act as a growth substrate. Electron microscopic analysis revealed localized areas of precipitation at the surfaces of nonstarved cells as well as precipitate in the surrounding medium. The addition of cadmium had no apparent effect on growth or acetogenesis. However, nickel and cadmium were synergistically toxic at a concentration (1 mM) at which neither alone was toxic. The amount of protein extracted from cadmium-treated cultures was twofold higher than that in control extracts, and the amount of total sulfide was fourfold higher in cultures containing cadmium than in control cultures. Comparable levels of cysteine desulfhydrase activity were observed in extracts of both cadmium-treated and control cultures, but the enzyme activity was expressed maximally about 24 h earlier in the cadmium-treated cultures than in the untreated controls. Images PMID:8439169

  4. Cadmium-free junction fabrication process for CuInSe.sub.2 thin film solar cells

    DOEpatents

    Ramanathan, Kannan V.; Contreras, Miguel A.; Bhattacharya, Raghu N.; Keane, James; Noufi, Rommel

    1999-01-01

    The present invention provides an economical, simple, dry and controllable semiconductor layer junction forming process to make cadmium free high efficiency photovoltaic cells having a first layer comprised primarily of copper indium diselenide having a thin doped copper indium diselenide n-type region, generated by thermal diffusion with a group II(b) element such as zinc, and a halide, such as chlorine, and a second layer comprised of a conventional zinc oxide bilayer. A photovoltaic device according the present invention includes a first thin film layer of semiconductor material formed primarily from copper indium diselenide. Doping of the copper indium diselenide with zinc chloride is accomplished using either a zinc chloride solution or a solid zinc chloride material. Thermal diffusion of zinc chloride into the copper indium diselenide upper region creates the thin n-type copper indium diselenide surface. A second thin film layer of semiconductor material comprising zinc oxide is then applied in two layers. The first layer comprises a thin layer of high resistivity zinc oxide. The second relatively thick layer of zinc oxide is doped to exhibit low resistivity.

  5. Cadmium-free junction fabrication process for CuInSe{sub 2} thin film solar cells

    SciTech Connect

    Ramanathan, K.V.; Contreras, M.A.; Bhattacharya, R.N.; Keane, J.; Noufi, R.

    1999-09-07

    The present invention provides an economical, simple, dry and controllable semiconductor layer junction forming process to make cadmium free high efficiency photovoltaic cells having a first layer comprised primarily of copper indium diselenide having a thin doped copper indium diselenide n-type region, generated by thermal diffusion with a group II(b) element such as zinc, and a halide, such as chlorine, and a second layer comprised of a conventional zinc oxide bilayer. A photovoltaic device according the present invention includes a first thin film layer of semiconductor material formed primarily from copper indium diselenide. Doping of the copper indium diselenide with zinc chloride is accomplished using either a zinc chloride solution or a solid zinc chloride material. Thermal diffusion of zinc chloride into the copper indium diselenide upper region creates the thin n-type copper indium diselenide surface. A second thin film layer of semiconductor material comprising zinc oxide is then applied in two layers. The first layer comprises a thin layer of high resistivity zinc oxide. The second relatively thick layer of zinc oxide is doped to exhibit low resistivity.

  6. Recent developments in low cost silicon solar cells for terrestrial applications. [sheet production methods

    NASA Technical Reports Server (NTRS)

    Leipold, M. H.

    1978-01-01

    A variety of techniques may be used for photovoltaic energy systems. Concentrated or not concentrated sunlight may be employed, and a number of materials can be used, including silicon, gallium arsenide, cadmium sulfide, and cadmium telluride. Most of the experience, however, has been obtained with silicon cells employed without sunlight concentration. An industrial base exists at present for producing solar cells at a price in the range from $15 to $30 per peak watt. A major federal program has the objective to reduce the price of power provided by silicon solar systems to approximately $1 per peak watt in the early 1980's and $0.50 per watt by 1986. The approaches considered for achieving this objective are discussed.

  7. I-III-VI.sub.2 based solar cell utilizing the structure CuInGaSe.sub.2 CdZnS/ZnO

    DOEpatents

    Chen, Wen S.; Stewart, John M.

    1992-01-07

    A thin film I-III-VI.sub.2 based solar cell having a first layer of copper indium gallium selenide, a second layer of cadmium zinc sulfide, a double layer of zinc oxide, and a metallization structure comprised of a layer of nickel covered by a layer of aluminum. An optional antireflective coating may be placed on said metallization structure. The cadmium zinc sulfide layer is deposited by means of an aqueous solution growth deposition process and may actually consist of two layers: a low zinc content layer and a high zinc content layer. Photovoltaic efficiencies of 12.5% at Air Mass 1.5 illumination conditions and 10.4% under AMO illumination can be achieved.

  8. Investigation of II-VI Semiconductor Quantum Dots for Sensitized Solar Cell Applications

    NASA Astrophysics Data System (ADS)

    Horoz, Sabit

    Semiconductor nanocrystals, also referred to as quantum dots (QDs) which have advantages of low-cost, photostability, high molar extinction coefficients and size-dependent optical properties, have been the focus of great scientific and technological efforts in solar cells development. Due to the multi-electron generation effect, the theoretical maximum efficiency of quantum dots sensitized solar cells (QDSSCs) is much higher than that of dye sensitized solar cells (DSSCs). Thus QDSSCs have a clear potential to overtake the efficiency of other kinds of solar cells. Doped semiconductor QDs can not only retain nearly all advantages of intrinsic QDs, but also have additional absorption bands for improved efficiency. This approach is particularly important for wide band gap semiconductors, for example, zinc based QDs. Zinc based are desirable candidates as they are inexpensive, earth abundant and nontoxic. When doped, they can cover a broad range of visible spectrum. In my project, I aim at developing novel methods for the preparation of II-VI QDs and investigating the effects of doping on the properties and performances of QDSSCs. Cadmium selenide (CdSe), manganese doped cadmium selenide (Mn:CdSe), and manganese doped zinc sulfide (Mn:ZnS) QDs have been synthesized by laser ablation in water. The structural and luminescent properties of the QDs have been investigated. In addition, QDSSC performances of the samples have been measured using nanowire electrode made of ZnO and Zn2SnO 4. I have also successfully synthesized europium doped zinc sulfide (Eu:ZnS) and manganese doped cadmium sulfide (Mn:CdS) nanoparticles by wet chemical method, and analyzed structural, optical, and magnetic properties as well as the device performance of the nanoparticles.

  9. Sulfide chemiluminescence detection

    DOEpatents

    Spurlin, S.R.; Yeung, E.S.

    1985-11-26

    A method is described for chemiluminescently determining a sulfide which is either hydrogen sulfide or methyl mercaptan by reacting the sulfide with chlorine dioxide at low pressure and under conditions which allow a longer reaction time in emission of a single photon for every two sulfide containing species, and thereafter, chemiluminescently detecting and determining the sulfide. The invention also relates not only to the detection method, but the novel chemical reaction and a specifically designed chemiluminescence detection cell for the reaction. 4 figs.

  10. Sulfide chemiluminescence detection

    DOEpatents

    Spurlin, Stanford R.; Yeung, Edward S.

    1985-01-01

    A method of chemiluminescently determining a sulfide which is either hydrogen sulfide or methyl mercaptan by reacting the sulfide with chlorine dioxide at low pressure and under conditions which allow a longer reaction time in emission of a single photon for every two sulfide containing species, and thereafter, chemiluminescently detecting and determining the sulfide. The invention also relates not only to the detection method, but the novel chemical reaction and a specifically designed chemiluminescence detection cell for the reaction.

  11. Separation of Silver from a Zinc Sulfide Concentrate by a Co-smelting Process

    NASA Astrophysics Data System (ADS)

    Yang, Jian-Guang; Zhang, Xu-Liang; Yang, Jian-Ying

    2015-02-01

    The main purpose of this study is to characterize and separate silver from a zinc sulfide concentrate through co-smelting with lead oxide dust. This article reports the optimization of process parameters, such as flux composition, co-smelting temperature, flux dosage, and charging material compositions, on the silver separation rate and resultant zinc sulfide concentrate grade. A maximum silver recovery of 97.36%, zinc sulfide concentrate grade of 43.91%, and 98.25% crude lead enriched silver are obtained under the optimized condition of temperature 900°C, smelting duration 120 min, 27.5 wt.% zinc sulfide concentrate, and 15.0 wt.% lead oxide dust, flux composition . This co-smelting process was proven effective to separate silver from zinc sulfide concentrate and produce a higher grade zinc sulfide concentrate. Especially, it was found to be effective to separate some associated impurities from zinc sulfide concentrate, such as arsenic, cadmium, fluorine, and chlorine etc.

  12. CdS and CdS/CdSe sensitized ZnO nanorod array solar cells prepared by a solution ions exchange process

    SciTech Connect

    Chen, Ling; Gong, Haibo; Zheng, Xiaopeng; Zhu, Min; Zhang, Jun; Yang, Shikuan; Cao, Bingqiang

    2013-10-15

    Graphical abstract: - Highlights: • CdS and CdS/CdSe quantum dots are assembled on ZnO nanorods by ion exchange process. • The CdS/CdSe sensitization of ZnO effectively extends the absorption spectrum. • The performance of ZnO/CdS/CdSe cell is improved by extending absorption spectrum. - Abstract: In this paper, cadmium sulfide (CdS) and cadmium sulfide/cadmium selenide (CdS/CdSe) quantum dots (QDs) are assembled onto ZnO nanorod arrays by a solution ion exchange process for QD-sensitized solar cell application. The morphology, composition and absorption properties of different photoanodes were characterized with scanning electron microscope, transmission electron microscope, energy-dispersive X-ray spectrum and Raman spectrum in detail. It is shown that conformal and uniform CdS and CdS/CdSe shells can grow on ZnO nanorod cores. Quantum dot sensitized solar cells based on ZnO/CdS and ZnO/CdS/CdSe nanocable arrays were assembled with gold counter electrode and polysulfide electrolyte solution. The CdS/CdSe sensitization of ZnO can effectively extend the absorption spectrum up to 650 nm, which has a remarkable impact on the performance of a photovoltaic device by extending the absorption spectrum. Preliminary results show one fourth improvement in solar cell efficiency.

  13. Experimental and theoretical investigations of cadmium diffusion in vacancy-rich Cu(In, Ga)Se2 material

    NASA Astrophysics Data System (ADS)

    Biderman, Norbert J.

    Copper indium gallium selenide (Cu(In,Ga)Se2 or CIGS) has become a significant topic of research and development for photovoltaic application. CIGS photovoltaic devices have demonstrated record conversion efficiencies however are still below the maximum solar conversion efficiency. Losses in performance have been attributed structural defects including vacancies, doping, grain boundaries, and compositional non-uniformity that are poorly understood and controlled. The cadmium sulfide (CdS) buffer layer plays a critical role in high-performance CIGS photovoltaic devices, serving as the n-type component of the p-n junction formed with the p-type CIGS absorber layer. Cadmium diffusion into the CIGS surface during CdS deposition creates a buried p-n homojunction in addition to the CIGS/CdS p-n heterojunction. CdS is believed to assist in reducing carrier recombination at the CIGS/CdS interface, an important attribute of high-efficiency solar cells. In the present work, cadmium diffusion mechanisms in CIGS are experimentally investigated via secondary ion mass spectroscopy (SIMS) and Auger electron spectroscopy (AES). Two cadmium diffusion profiles with distinct Arrhenius diffusion kinetics within a single depth profile of the CIGS thin film are observed with SIMS and AES: an intense first-stage diffusion profile directly below the CIGS/CdS interface and a long-range, second-stage diffusion profile that extends deep into the thin film. Cadmium grain boundary diffusion is also detected in fine-grain CIGS samples. These multiple diffusion processes are quantified in the present work, and the two-stage cadmium diffusion profiles suggest distinctive lattice diffusion mechanisms. Calculations and modeling of general impurity diffusion via interstitial sites in CIGS are also conducted via numerical including cadmium, iron, and zinc. In the numerical simulations, the standard diffusion-reaction kinetics theory is extended to vacancy-rich materials like CIGS that contain 1 at

  14. Direct examination of cadmium bonding in rat tissues dosed with mine wastes and cadmium-containing solutions

    NASA Astrophysics Data System (ADS)

    Diacomanolis, V.; Ng, J. C.; Sadler, R.; Harris, H. H.; Nomura, M.; Noller, B. N.

    2010-06-01

    Direct examination by XANES and EXAFS of metal bonding in tissue can be demonstrated by examining cadmium uptake and bonding in animal tissue maintained at cryogenic temperatures. XANES at the K-edge of cadmium were collected at the Photon Factory Advanced Ring (PF-AR), NW10A beam line at KEK-Tsukuba-Japan. Rats fed with 1g mine waste containing 8-400 mg/kg cadmium per 200g body weight (b.w.) or dosed by oral gavage with either cadmium chloride solution alone (at 6 mg/kg b.w.) or in combination with other salts (As, Cu or Zn), 5 days/week for 6 weeks, had 0.1-7.5 and 8-86 mg/kg cadmium in the liver or kidney, respectively. Rats given intraperitoneally (ip) or intravenously (iv) 1-4 times with 1 mg/kg b.w. cadmium solution had 30-120 mg/kg cadmium in the liver or kidney. Tissues from rats were kept and transferred at cryogenic temperature and XANES were recorded at 20 K. The spectra for rat liver samples suggested conjugation of cadmium with glutathione or association with the sulfide bond (Cd-S) of proteins and peptides. EXAFS of rat liver fed by Cd and Zn solutions showed that Cd was clearly bound to S ligands with an inter-atomic distance of 2.54 Å for Cd-S that was similar to cadmium sulfide with an inter-atomic distance of 2.52 Å for Cd-S. Liver or kidney of rats fed with mine wastes did not give an edge in the XANES spectra indicating little uptake of cadmium by the animals. Longer and higher dosing regimen may be required in order to observe the same Cd-S bond in the rat tissue from mine wastes, including confirmation by EXAFS.

  15. Direct examination of cadmium bonding in rat tissues dosed with mine wastes and cadmium-containing solutions

    SciTech Connect

    Diacomanolis, V.; Ng, J. C.; Sadler, R.; Harris, H. H.; Nomura, M.; Noller, B. N.

    2010-06-23

    Direct examination by XANES and EXAFS of metal bonding in tissue can be demonstrated by examining cadmium uptake and bonding in animal tissue maintained at cryogenic temperatures. XANES at the K-edge of cadmium were collected at the Photon Factory Advanced Ring (PF-AR), NW10A beam line at KEK-Tsukuba-Japan. Rats fed with 1g mine waste containing 8-400 mg/kg cadmium per 200g body weight (b.w.) or dosed by oral gavage with either cadmium chloride solution alone (at 6 mg/kg b.w.) or in combination with other salts (As, Cu or Zn), 5 days/week for 6 weeks, had 0.1-7.5 and 8-86 mg/kg cadmium in the liver or kidney, respectively. Rats given intraperitoneally (ip) or intravenously (iv) 1-4 times with 1 mg/kg b.w. cadmium solution had 30-120 mg/kg cadmium in the liver or kidney. Tissues from rats were kept and transferred at cryogenic temperature and XANES were recorded at 20 K. The spectra for rat liver samples suggested conjugation of cadmium with glutathione or association with the sulfide bond (Cd-S) of proteins and peptides. EXAFS of rat liver fed by Cd and Zn solutions showed that Cd was clearly bound to S ligands with an inter-atomic distance of 2.54 A ring for Cd-S that was similar to cadmium sulfide with an inter-atomic distance of 2.52 A ring for Cd-S. Liver or kidney of rats fed with mine wastes did not give an edge in the XANES spectra indicating little uptake of cadmium by the animals. Longer and higher dosing regimen may be required in order to observe the same Cd-S bond in the rat tissue from mine wastes, including confirmation by EXAFS.

  16. Surface passivation of lead sulfide nanocrystals with low electron affinity metals: photoluminescence and photovoltaic performance.

    PubMed

    Tavakoli, Mohammad Mahdi; Mirfasih, Mohammad Hassan; Hasanzadeh, Soheil; Aashuri, Hossein; Simchi, Abdolreza

    2016-04-28

    During the last decade, solution-processed colloidal quantum dots (CQDs) have attracted significant attention for low-cost fabrication of optoelectronic devices. In this study, lead sulfide (PbS) CQDs were synthesized via the hot injection method and the effect of doping elements with low electron affinity, including cadmium, calcium and zinc, on the passivation of trap states was investigated. A red-shift in the luminescence emission was observed by doping through passivation of lead dangling bonds. Time-resolved photoluminescence measurements showed that the lifetime of charged carriers was significantly enhanced by cadmium doping (∼80%) which is quite noticeable compared with calcium- and zinc-doped nanocrystals. External quantum efficiency measurements on thin solid films (∼300 nm) prepared by spin coating supported improved lifetime of carriers through passivation of mid-gap trap states. In order to show the potential application of the doping process, bulk heterojunction CQD solar cells were fabricated. It was found that the power conversion efficiency (PCE) was improved up to ∼40%; the highest improvement was observed with the Cd treatment. Finally, density functional theory (DFT) and electrochemical impedance spectroscopy (EIS) were employed to study the effect of doping on the density of states. The results showed that doping with low electron affinity metals effectively reduced the deep trap states of PbS QDs.

  17. The Search for Interstellar Sulfide Grains

    NASA Technical Reports Server (NTRS)

    Keller, Lindsay P.; Messenger, Scott

    2010-01-01

    The lifecycle of sulfur in the galaxy is poorly understood. Fe-sulfide grains are abundant in early solar system materials (e.g. meteorites and comets) and S is highly depleted from the gas phase in cold, dense molecular cloud environments. In stark contrast, sulfur is essentially undepleted from the gas phase in the diffuse interstellar medium, indicating that little sulfur is incorporated into solid grains in this environment. It is widely believed that sulfur is not a component of interstellar dust grains. This is a rather puzzling observation unless Fe-sulfides are not produced in significant quantities in stellar outflows, or their lifetime in the ISM is very short due to rapid destruction. Fe sulfide grains are ubiquitous in cometary samples where they are the dominant host of sulfur. The Fe-sulfides (primarily pyrrhotite; Fe(1-x)S) are common, both as discrete 0.5-10 micron-sized grains and as fine (5-10 nm) nanophase inclusions within amorphous silicate grains. Cometary dust particles contain high abundances of well-preserved presolar silicates and organic matter and we have suggested that they should contain presolar sulfides as well. This hypothesis is supported by the observation of abundant Fe-sulfides grains in dust around pre- and post-main sequence stars inferred from astronomical spectra showing a broad 23 micron IR feature due to FeS. Fe-sulfide grains also occur as inclusions in bona fide circumstellar amorphous silicate grains and as inclusions within deuterium-rich organic matter in cometary dust samples. Our irradiation experiments show that FeS is far more resistant to radiation damage than silicates. Consequently, we expect that Fe sulfide stardust should be as abundant as silicate stardust in solar system materials.

  18. Charge-Transfer Complexation at Carminic Acid-CdS Interface and Its Impact on the Efficiency of Dye-Sensitized Solar Cells

    NASA Astrophysics Data System (ADS)

    Shahzad, Naila; Shah, Syed Mujtaba; Munir, Shamsa; Hana, Amina; Jabeen, Uzma; Nosheen, Erum; Habib, Banafsha; Khan, Arif Ullah; Hassan, Zubair; Siddiq, Muhammad; Hussain, Hazrat

    2015-04-01

    We report for the first time charge-transfer complex formation at the interface of carminic acid and cadmium sulfide (CdS) nanoparticles. The complex formation was confirmed by ultraviolet-visible (UV-vis) and fluorescence emission spectroscopy. Cadmium sulfide nanoparticles were synthesized by the wet chemical method and characterized by UV-vis spectroscopy, x-ray diffraction and transmission electron microscopy. Carminic acid, in different concentrations, was chemisorbed on the surface of CdS nanoparticles. Grafting of carminic acid on CdS was confirmed by Fourier transform infrared spectroscopy. Energy levels of the highest occupied molecular orbitals and lowest unoccupied molecular orbitals (LUMO) of both carminic acid and CdS nanoparticles matched well for the injection of electron from LUMO of carminic acid to the conduction band of cadmium sulfide. The photoactive nanohybrid material was used in dye-sensitized solar cells. The efficiency of carminic acid functionalized CdS nanoparticles was found to be double the value obtained for the reference device and remained constant over a certain concentration range owing to the complex formation at the interface. However, raising the concentration of carminic acid beyond 2.5 × 10-5 M resulted in a decrease in efficiency. This was ascribed to charge recombination due to the presence of ungrafted carminic acid molecules.

  19. The Study of Metal Sulfide as Efficient Counter Electrodes on the Performances of CdS/CdSe/ZnS-co-sensitized Hierarchical TiO2 Sphere Quantum Dot Solar Cells

    NASA Astrophysics Data System (ADS)

    Buatong, Nattha; Tang, I.-Ming; Pon-On, Weeraphat

    2017-03-01

    The effects of using different counter electrode metal sulfides on the performances of solar cells made with CdS/CdSe/ZnS quantum dots co-sensitized onto hierarchical TiO2 spheres (HTSs) used as photo-electrode are reported. The HTS in the QDSSCs is composed of an assembly of numerous TiO2 spheres made by the solvolthermal method. The photoelectrical performance of HTS/CdS/CdSe/ZnS coupled to CuS or to Cu2ZnSn(S1 - x Se x )4 with x = 0, 0.5, or 1.0 counter electrodes (CEs) were compared to those coupled to Pt CE. The HTS/CdS/CdSe/ZnS coupled to the CuS CE showed the highest power conversion efficiency η (of 3.46%). The efficiencies η of 1.88, 2.64, and 2.06% were obtained for CZTS ( x = 0), CZTS0.5Se0.5 ( x = 0.5), and CZTSe ( x = 1), respectively. These are significantly higher than those using a standard Pt CE ( η = 0.37%). These higher efficiencies are the results of the higher electrocatalytic activities when the metal sulfide CEs are used.

  20. The Study of Metal Sulfide as Efficient Counter Electrodes on the Performances of CdS/CdSe/ZnS-co-sensitized Hierarchical TiO2 Sphere Quantum Dot Solar Cells.

    PubMed

    Buatong, Nattha; Tang, I-Ming; Pon-On, Weeraphat

    2017-12-01

    The effects of using different counter electrode metal sulfides on the performances of solar cells made with CdS/CdSe/ZnS quantum dots co-sensitized onto hierarchical TiO2 spheres (HTSs) used as photo-electrode are reported. The HTS in the QDSSCs is composed of an assembly of numerous TiO2 spheres made by the solvolthermal method. The photoelectrical performance of HTS/CdS/CdSe/ZnS coupled to CuS or to Cu2ZnSn(S1 - x Se x )4 with x = 0, 0.5, or 1.0 counter electrodes (CEs) were compared to those coupled to Pt CE. The HTS/CdS/CdSe/ZnS coupled to the CuS CE showed the highest power conversion efficiency η (of 3.46%). The efficiencies η of 1.88, 2.64, and 2.06% were obtained for CZTS (x = 0), CZTS0.5Se0.5 (x = 0.5), and CZTSe (x = 1), respectively. These are significantly higher than those using a standard Pt CE (η = 0.37%). These higher efficiencies are the results of the higher electrocatalytic activities when the metal sulfide CEs are used.

  1. Cadmium sulfide and cadmium selenide/cadmium sulfide nanoparticles stabilized in water with poly(cysteine acrylamide).

    PubMed

    Sherman, Robert L; Chen, Yiyan; Ford, Warren T

    2004-11-01

    Cysteine acrylamide (N-acryloyl L-cysteine) stabilizes CdS nanoparticles as the particles form in aqueous dispersions. Cysteine acrylamide also exchanges for citrate on the surfaces of CdSe and core/shell CdSe/CdS nanoparticles to provide greater stability. Heating of the nanoparticle dispersions polymerizes the cysteine acrylamide on the surface to form a more efficient polydentate stabilizer. The polymer-coated nanoparticle dispersions are colloidally stable even after removal of low molecular weight solutes by dialysis. Emission quantum yields of the polymer-coated CdSe and CdSe/CdS samples were 0.9% and 2.6%, respectively, after aging of the samples in light. CdSe/CdS coated with poly(cysteine acrylamide) is colloidally stable for at least two years in the dark at 5 degrees C.

  2. SULFIDE MINERALS IN SEDIMENTS

    EPA Science Inventory

    The formation processes of metal sulfides in sediments, especially iron sulfides, have been the subjects of intense scientific research because of linkages to the global biogeochemical cycles of iron, sulfur, carbon, and oxygen. Transition metal sulfides (e.g., NiS, CuS, ZnS, Cd...

  3. SULFIDE MINERALS IN SEDIMENTS

    EPA Science Inventory

    The formation processes of metal sulfides in sediments, especially iron sulfides, have been the subjects of intense scientific research because of linkages to the global biogeochemical cycles of iron, sulfur, carbon, and oxygen. Transition metal sulfides (e.g., NiS, CuS, ZnS, Cd...

  4. Low cost preparation of Cu2ZnSnS4 and Cu2ZnSn(SxSe1-x)4 from binary sulfide nanoparticles for solar cell application

    NASA Astrophysics Data System (ADS)

    Chen, Guilin; Yuan, Chenchen; Liu, Jiwan; Deng, Yitao; Jiang, Guoshun; Liu, Weifeng; Zhu, Changfei

    2014-09-01

    A low-cost non-vacuum process for fabrication of Cu2ZnSnS4 (CZTS) and Cu2ZnSn(SxSe1-x)4 (CZTSSe) films by solvent-free mechanochemical method and doctor blade process is described. First, CuS, ZnS and SnS nanoparticles are synthesized via a facile, solvent-free route, which is low cost and easy to scale-up. Second, the sulfides nanoparticulates precursors are deposited in a thin layer by doctor blade technique. Finally, the dry layers are sintered into CZTS/CZTSSe thin films. Different annealing processes are used, and the influences of incorporation of sulfur/selenium on the CZTS/CZTSSe films have been investigated. These structure, morphology and optical properties of CZTS/CZTSSe films are suitable for thin film solar cell fabrication.

  5. Insights into cadmium diffusion mechanisms in two-stage diffusion profiles in solar-grade Cu(In,Ga)Se{sub 2} thin films

    SciTech Connect

    Biderman, N. J.; Sundaramoorthy, R.; Haldar, Pradeep; Novak, Steven W.; Lloyd, J. R.

    2015-12-07

    Cadmium diffusion experiments were performed on polished copper indium gallium diselenide (Cu(In,Ga)Se{sub 2} or CIGS) samples with resulting cadmium diffusion profiles measured by time-of-flight secondary ion mass spectroscopy. Experiments done in the annealing temperature range between 275 °C and 425 °C reveal two-stage cadmium diffusion profiles which may be indicative of multiple diffusion mechanisms. Each stage can be described by the standard solutions of Fick's second law. The slower cadmium diffusion in the first stage can be described by the Arrhenius equation D{sub 1} = 3 × 10{sup −4} exp (− 1.53 eV/k{sub B}T) cm{sup 2} s{sup −1}, possibly representing vacancy-meditated diffusion. The faster second-stage diffusion coefficients determined in these experiments match the previously reported cadmium diffusion Arrhenius equation of D{sub 2} = 4.8 × 10{sup −4} exp (−1.04 eV/k{sub B}T) cm{sup 2} s{sup −1}, suggesting an interstitial-based mechanism.

  6. CdS: Characterization and recent advances in CdTe solar cell performance

    SciTech Connect

    Ferekides, C.; Marinskiy, D.; Morel, D.L.

    1997-12-31

    Cadmium sulfide (CdS) films deposited by chemical bath deposition (CBD) have been used for the fabrication of high efficiency CdTe and CuIn{sub 1{minus}x}Ga{sub x}Se{sub 2} thin film solar cells. An attractive alternative deposition technology with manufacturing advantages over the CBD is the close spaced sublimation (CSS). In this work CdTe/CdS solar cells prepared entirely by the CSS process exhibited 15.0% efficiencies under global AM1.5 conditions as verified at the National Renewable Energy Laboratory. This paper reports on studies carried out on as deposited and heat treated CSS CdS films and all CSS CdTe/CdS solar cells using photoluminescence, x-ray diffraction, and I-V-T measurements.

  7. Sodium antimony sulfide (NaSbS2): Turning an unexpected impurity into a promising, environmentally friendly novel solar absorber material

    NASA Astrophysics Data System (ADS)

    Rahayu, Siti Utari; Chou, Chia-Ling; Suriyawong, Nipapon; Aragaw, Belete Asefa; Shi, Jen-Bin; Lee, Ming-Way

    2016-11-01

    We present a novel absorber material—NaSbS2—for solar cells. NaSbS2 is formed as an unexpected byproduct in the chemical synthesis of Sb2S3. However, NaSbS2 has many attractive features for a solar material. Here single phase NaSbS2 nanoparticles were synthesized through solution processing. NaSbS2 semiconductor-sensitized solar cells were demonstrated for the first time. The best cell yielded Jsc = 10.76 mA/cm2, Voc = 0.44 V, FF = 48.6%, and efficiency η = 2.30% under 1 sun. At the reduced 0.1 sun, the η increased to 3.18%—a respectable η for a new solar material.

  8. Nanotoxicological evaluation of oxidative responses in rat nephrocytes induced by cadmium

    PubMed Central

    Trabelsi, Hamdi; Azzouz, Inès; Ferchichi, Soumaya; Tebourbi, Olfa; Sakly, Mohsen; Abdelmelek, Hafedh

    2013-01-01

    The aim of this study was to investigate the interaction of cadmium chloride with mineral elements in rat nephrocytes in terms of the biosynthesis of nanocomplexes. The results show that selenium supplementation enhanced cadmium accumulation in kidneys. Analysis of the fluorescence revealed an increase in red fluorescence in the kidneys of rats co-exposed to cadmium and selenium. Interestingly, X-ray diffraction measurements carried out on kidney fractions of co-exposed rats point to the biosynthesis of cadmium selenide and/or sulfide nanoparticles (about 62 nm in size). Oxidative stress assays showed the ability of selenium to reduce lipid peroxidation and to restore glutathione peroxidase and superoxide dismutase activity in kidneys. Hence, cadmium complexation with selenium and sulfur at a nanoscale level could reduce oxidative stress induced by cadmium in kidneys. PMID:24043937

  9. Cadmium and the kidney.

    PubMed Central

    Friberg, L

    1984-01-01

    The paper is a review of certain aspects of importance of cadmium and the kidney regarding the assessment of risks and understanding of mechanisms of action. The review discusses the following topics: history and etiology of cadmium-induced kidney dysfunction and related disorders; cadmium metabolism, metallothionein and kidney dysfunction; cadmium in urine as indicator of body burden, exposure and kidney dysfunction; cadmium levels in kidney and liver as indicators of kidney dysfunction; characteristics of early kidney dysfunction; the critical concentration concept; critical concentrations of cadmium in kidney cortex; and prognosis. PMID:6734547

  10. One-step high-temperature solvothermal synthesis of TiO2/sulfide nanocomposite spheres and their solar visible-light applications.

    PubMed

    Ding, Shangjun; Yin, Xin; Lü, Xujie; Wang, Yaoming; Huang, Fuqiang; Wan, Dongyun

    2012-01-01

    A one-step high-temperature hydrated-sulfate assisted solvothermal method has been developed to synthesize TiO(2)/sulfide nanocomposite spheres. Different hybrid spheres of TiO(2)/CdS, TiO(2)/Cu(2)S, TiO(2)/FeS, TiO(2)/Co(9)S(8), and TiO(2)/ZnS were readily prepared by exploiting different hydrated sulfate. The hydrated sulfate has been proved to play multifunctional roles during the synthetic process, such as spherical template, water supplier, and composition controller. Nanocrystal CdS can be reduced from CdSO(4) at a high solvothermal temperature of 350 °C, and the TiO(2)/CdS nanocomposite spheres prepared by this method exhibit superior visible-light-driven photocatalytic efficiency because of its effective heterointerface and high crystallinity. © 2011 American Chemical Society

  11. Process for fabricating polycrystalline semiconductor thin-film solar cells, and cells produced thereby

    DOEpatents

    Wu, Xuanzhi; Sheldon, Peter

    2000-01-01

    A novel, simplified method for fabricating a thin-film semiconductor heterojunction photovoltaic device includes initial steps of depositing a layer of cadmium stannate and a layer of zinc stannate on a transparent substrate, both by radio frequency sputtering at ambient temperature, followed by the depositing of dissimilar layers of semiconductors such as cadmium sulfide and cadmium telluride, and heat treatment to convert the cadmium stannate to a substantially single-phase material of a spinel crystal structure. Preferably, the cadmium sulfide layer is also deposited by radio frequency sputtering at ambient temperature, and the cadmium telluride layer is deposited by close space sublimation at an elevated temperature effective to convert the amorphous cadmium stannate to the polycrystalline cadmium stannate with single-phase spinel structure.

  12. Metal Sulfides as Sensing Materials for Chemoresistive Gas Sensors

    PubMed Central

    Gaiardo, Andrea; Fabbri, Barbara; Guidi, Vincenzo; Bellutti, Pierluigi; Giberti, Alessio; Gherardi, Sandro; Vanzetti, Lia; Malagù, Cesare; Zonta, Giulia

    2016-01-01

    This work aims at a broad overview of the results obtained with metal-sulfide materials in the field of chemoresistive gas sensing. Indeed, despite the well-known electrical, optical, structural and morphological features previously described in the literature, metal sulfides present lack of investigation for gas sensing applications, a field in which the metal oxides still maintain a leading role owing to their high sensitivity, low cost, small dimensions and simple integration, in spite of the wide assortment of sensing materials. However, despite their great advantages, metal oxides have shown significant drawbacks, which have led to the search for new materials for gas sensing devices. In this work, Cadmium Sulfide and Tin (IV) Sulfide were investigated as functional materials for thick-film chemoresistive gas-sensors fabrication and they were tested both in thermo- and in photo-activation modes. Furthermore, electrical characterization was carried out in order to verify their gas sensing properties and material stability, by comparing the results obtained with metal sulfides to those obtained by using their metal-oxides counterparts. The results highlighted the possibility to use metal sulfides as a novel class of sensing materials, owing to their selectivity to specific compounds, stability, and the possibility to operate at room temperature. PMID:26927120

  13. Aquatic Life Criteria - Cadmium

    EPA Pesticide Factsheets

    Documents pertaining to 2016 Acute and Chronic Aquatic Life Ambient Water Quality Criteria for Cadmium (Freshwater, Estuarine/marine). These documents contain the safe levels of Cadmium in water that should protect to the majority of species.

  14. Cadmium and zinc relationships.

    PubMed

    Elinder, C G; Piscator, M

    1978-08-01

    Cadmium and zinc concentrations in kidney and liver have been measured under different exposure situations in different species including man. The results show that zinc increases almost equimolarly with cadmium in kidney after long-term low-level exposure to cadmium, e.g., in man, horse, pig, and lamb. In contrast, the increase of zinc follows that of cadmium to only a limited extent, e.g., in guinea pig, rabbit, rat, mouse, and chicks. In liver, the cadmium--zinc relationship seems to be reversed in such a way that zinc increases with cadmium more markedly in laboratory animals than in higher mammals. These differences between cadmium and zinc relationships in humans and large farm animals and those in commonly used laboratory animals must be considered carefully before experimental data on cadmium and zinc relationships in laboratory animals can be extrapolated to humans.

  15. Process for removing and detoxifying cadmium from scrap metal including mixed waste

    SciTech Connect

    Kronberg, J.W.

    1994-07-01

    Cadmium-bearing scrap from nuclear applications, such as neutron shielding and reactor control and safety rods, must usually be handled as mixed waste since it is radioactive and the cadmium in it is both leachable and highly toxic. Removing the cadmium from this scrap, and converting it to a nonleachable and minimally radioactive form, would greatly simplify disposal or recycling. A process now under development will do this by shredding the scrap; leaching it with reagents which selectively dissolve out the cadmium; reprecipitating the cadmium as its highly insoluble sulfide; then fusing the sulfide into a glassy matrix to bring its leachability below EPA limits before disposal. Alternatively, the cadmium may be recovered for reuse. A particular advantage of the process is that all reagents (except the glass frit) can easily be recovered and reused in a nearly closed cycle, minimizing the risk of radioactive release. The process does not harm common metals such as aluminum, iron and stainless steel, and is also applicable to non-nuclear cadmium-bearing scrap such as nickel-cadmium batteries.

  16. Sulfide Mineralogy and Geochemistry

    NASA Astrophysics Data System (ADS)

    Dilles, John

    2007-02-01

    Reviews in Mineralogy and Geochemistry Series, Volume 61 David J. Vaughan, Editor Geochemical Society and Mineralogical Society of America; ISBN 0-939950-73-1 xiii + 714 pp.; 2006; $40. Sulfide minerals as a class represent important minor rock-forming minerals, but they are generally known as the chief sources of many economic metallic ores. In the past two decades, sulfide research has been extended to include important roles in environmental geology of sulfide weathering and resultant acid mine drainage, as well as in geomicrobiology in which bacteria make use of sulfides for metabolic energy sources. In the latter respect, sulfides played an important role in early evolution of life on Earth and in geochemical cycling of elements in the Earth's crust and hydrosphere.

  17. Cadmium purification with a vibrating reactor

    SciTech Connect

    Torres, N.; Esna-Ashari, M.; Biallas, H.; Kangas, K.

    1986-08-01

    While electrolytically producing zinc from sulfide concentrates, purification is the most significant step. Impurities such as Co, Sn, Ge, Ni and Sb can cause extensive redissolution of the electrodeposited zinc, thus diminishing current efficiency. Other metals, particularly cadmium, lead and copper, can negatively affect zinc properties by deposition on the cathode. It is standard practice to use atomized zinc dust as a reducing agent in the purification process, either alone or combined with additives. In conventional operations, special facilities are necessary to produce zinc dust in an amount close to 8wt% of cathode production. This paper examines a technique which makes use of zinc granules instead of dust.

  18. Sulfide ions as modulators of metal-thiolate cluster size in a plant metallothionein.

    PubMed

    Huber, Tamara; Freisinger, Eva

    2013-06-28

    Metallothioneins are small cysteine-rich proteins coordinating various transition metal ions preferably with the electron configuration d(10). They are ubiquitously present in all phyla, and next to phytochelatins they represent a successful molecular concept for high-capacity metal ion binding. Recent studies showed the incorporation of sulfide ions into the metal-thiolate cluster of metallothionein 2 from the plant Cicer arietinum (cicMT2) increasing the cadmium binding capacity and stability of the cluster. In the present work, the sulfide-induced structural changes accompanying the cluster formation and the sulfide-modulated increase in cluster size are analyzed in detail with a variety of analytical and spectroscopic techniques. Evaluation of the mechanism of sulfide containing Cd(II)-thiolate cluster formation in cicMT2 reveals a strong dependence on the sequence of metal and sulfide additions for successful sulfide incorporation. To probe the general ability of metallothioneins to form sulfide containing larger metal-thiolate clusters, analogous experiments were performed with a mammalian metallothionein. The observation that the cadmium binding ability of rabbit liver MT2A was only slightly increased led to the development of a hypothesis in which the long cysteine-free linker regions present in certain plant metallothioneins may contribute to the accommodation of the respective larger cluster assemblies.

  19. Sunlight Promotes Fast Release of Hazardous Cadmium from Widely-Used Commercial Cadmium Pigment.

    PubMed

    Liu, Huiting; Gao, Han; Long, Mingce; Fu, Heyun; Alvarez, Pedro J J; Li, Qilin; Zheng, Shourong; Qu, Xiaolei; Zhu, Dongqiang

    2017-06-20

    Cadmium pigments are widely used in the polymer and ceramic industry. Their potential environmental risk is under debate, being the major barrier for appropriate regulation. We show that 83.0 ± 0.2% of hazardous cadmium ion (Cd(2+)) was released from the commercial cadmium sulfoselenide pigment (i.e., cadmium red) in aqueous suspension within 24 h under simulated sunlit conditions. This photodissolution process also generated sub-20 nm pigment nanoparticles. Cd(2+) release is attributed to the reactions between photogenerated holes and the pigment lattices. The photodissolution process can be activated by both ultraviolet and visible light in the solar spectrum. Irradiation under alkaline conditions or in the presence of phosphate and carbonate species resulted in reduced charge carrier energy or the formation of insoluble and photostable cadmium precipitates on pigment surfaces, mitigating photodissolution. Tannic acid inhibited the photodissolution process by light screening and scavenging photogenerated holes. The fast release of Cd(2+) from the pigment was further confirmed in river water under natural sunlight, with 38.6 ± 0.1% of the cadmium released within 4 h. Overall, this study underscores the importance to account for photochemical effects to inform risk assessments and regulations of cadmium pigments which are currently based on their low solubility.

  20. Facile room-temperature synthesis of carboxylated graphene oxide-copper sulfide nanocomposite with high photodegradation and disinfection activities under solar light irradiation

    NASA Astrophysics Data System (ADS)

    Yu, Shuyan; Liu, Jincheng; Zhu, Wenyu; Hu, Zhong-Ting; Lim, Teik-Thye; Yan, Xiaoli

    2015-11-01

    Carboxylic acid functionalized graphene oxide-copper (II) sulfide nanoparticle composite (GO-COOH-CuS) was prepared from carboxylated graphene oxide and copper precursor in dimethyl sulfoxide (DMSO) by a facile synthesis process at room temperature. The high-effective combination, the interaction between GO-COOH sheets and CuS nanoparticles, and the enhanced visible light absorption were confirmed by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectra (DRS) and Photoluminescence (PL) spectra. The as-synthesized GO-COOH-CuS nanocomposite exhibited excellent photocatalytic degradation performance of phenol and rhodamine B, high antibacterial activity toward E. coli and B. subtilis, and good recovery and reusability. The influence of CuS content, the synergistic reaction between CuS and GO-COOH, and the charge-transfer mechanism were systematically investigated. The facile and low-energy synthesis process combined with the excellent degradation and antibacterial performance signify that the GO-COOH-CuS has a great potential for water treatment application.

  1. Facile room-temperature synthesis of carboxylated graphene oxide-copper sulfide nanocomposite with high photodegradation and disinfection activities under solar light irradiation

    PubMed Central

    Yu, Shuyan; Liu, Jincheng; Zhu, Wenyu; Hu, Zhong-Ting; Lim, Teik-Thye; Yan, Xiaoli

    2015-01-01

    Carboxylic acid functionalized graphene oxide-copper (II) sulfide nanoparticle composite (GO-COOH-CuS) was prepared from carboxylated graphene oxide and copper precursor in dimethyl sulfoxide (DMSO) by a facile synthesis process at room temperature. The high-effective combination, the interaction between GO-COOH sheets and CuS nanoparticles, and the enhanced visible light absorption were confirmed by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectra (DRS) and Photoluminescence (PL) spectra. The as-synthesized GO-COOH-CuS nanocomposite exhibited excellent photocatalytic degradation performance of phenol and rhodamine B, high antibacterial activity toward E. coli and B. subtilis, and good recovery and reusability. The influence of CuS content, the synergistic reaction between CuS and GO-COOH, and the charge-transfer mechanism were systematically investigated. The facile and low-energy synthesis process combined with the excellent degradation and antibacterial performance signify that the GO-COOH-CuS has a great potential for water treatment application. PMID:26553709

  2. A Two-Step Absorber Deposition Approach To Overcome Shunt Losses in Thin-Film Solar Cells: Using Tin Sulfide as a Proof-of-Concept Material System

    SciTech Connect

    Steinmann, Vera; Chakraborty, Rupak; Rekemeyer, Paul H.; Hartman, Katy; Brandt, Riley E.; Polizzotti, Alex; Yang, Chuanxi; Moriarty, Tom; Gradečak, Silvija; Gordon, Roy G.; Buonassisi, Tonio

    2016-08-31

    As novel absorber materials are developed and screened for their photovoltaic (PV) properties, the challenge remains to reproducibly test promising candidates for high-performing PV devices. Many early-stage devices are prone to device shunting due to pinholes in the absorber layer, producing 'false-negative' results. Here, we demonstrate a device engineering solution toward a robust device architecture, using a two-step absorber deposition approach. We use tin sulfide (SnS) as a test absorber material. The SnS bulk is processed at high temperature (400 degrees C) to stimulate grain growth, followed by a much thinner, low-temperature (200 degrees C) absorber deposition. At a lower process temperature, the thin absorber overlayer contains significantly smaller, densely packed grains, which are likely to provide a continuous coating and fill pinholes in the underlying absorber bulk. We compare this two-step approach to the more standard approach of using a semi-insulating buffer layer directly on top of the annealed absorber bulk, and we demonstrate a more than 3.5x superior shunt resistance Rsh with smaller standard error ..sigma..Rsh. Electron-beam-induced current (EBIC) measurements indicate a lower density of pinholes in the SnS absorber bulk when using the two-step absorber deposition approach. We correlate those findings to improvements in the device performance and device performance reproducibility.

  3. One-step solvothermal tailoring the compositions and phases of nickel cobalt sulfides on conducting oxide substrates as counter electrodes for efficient dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Huang, Niu; Li, Guowang; Huang, Hua; Sun, Panpan; Xiong, Tianli; Xia, Zhifen; Zheng, Fang; Xu, Jixing; Sun, Xiaohua

    2016-12-01

    Several nickel cobalt sulfide (Ni-Co-S) counter electrodes (CEs) are prepared, and the Ni-Co-S nanoparticles are in-situ grown on SnO2: F (FTO) transparent conductive glasses via a facile solvothermal process, in which thiourea is used as the sulfurizing reagent. The X-ray diffraction, scanning electron microscopy, and energy dispersive spectrometer are employed to measure the microstructure and composition of the Ni-Co-S CEs. When a proper amount of thiourea is adopted, fine crystalline NiCo2S4 CE is obtained. When the amount of thiourea is small or large, (Ni,Co)4S3 or (Ni,Co)3S4 CE is acquired, respectively. Cyclic voltammetry, electrochemical impedance spectroscopy, Tafel polarization and open-circuit voltage decay (OCVD) measurements all demonstrate that the electrocatalytic activities and electrical conductivities of these Ni-Co-S CEs all approach or exceed those of Pt-pyrolysis CE. Their superior electrochemical performances are further confirmed by fabricating DSSCs with the Ni-Co-S CEs, they display similar or better photo-electric conversion efficiencies to/than the Pt-pyrolysis counterpart.

  4. Utilization of Metal Sulfide Material of (CuGa)(1-x)Zn(2x)S2 Solid Solution with Visible Light Response in Photocatalytic and Photoelectrochemical Solar Water Splitting Systems.

    PubMed

    Kato, Takaaki; Hakari, Yuichiro; Ikeda, Satoru; Jia, Qingxin; Iwase, Akihide; Kudo, Akihiko

    2015-03-19

    Upon forming a solid solution between CuGaS2 and ZnS, we have successfully developed a highly active (CuGa)(1-x)Zn(2x)S2 photocatalyst for H2 evolution in the presence of sacrificial reagents under visible light irradiation. The Ru-loaded (CuGa)0.8Zn0.4S2 functioned as a H2-evolving photocatalyst in a Z-scheme system with BiVO4 of an O2-evolving photocatalyst and Co complexes of an electron mediator. The Z-scheme system split water into H2 and O2 under visible light and simulated sunlight irradiation. The (CuGa)(1-x)Zn(2x)S2 possessed a p-type semiconductor character. The photoelectrochemical cell with a Ru-loaded (CuGa)0.5ZnS2 photocathode and a CoO(x)-modified BiVO4 photoanode split water even without applying an external bias. Thus, we successfully demonstrated that the metal sulfide material group can be available for Z-scheme and electrochemical systems to achieve solar water splitting into H2 and O2.

  5. Design of pilot-scale solar photocatalytic reactor for the generation of hydrogen from alkaline sulfide wastewater of sewage treatment plant.

    PubMed

    Priya, R; Kanmani, S

    2013-01-01

    Experiments were conducted for photocatalytic generation of renewable fuel hydrogen from sulphide wastewater from the sewage treatment plant. In this study, pilot-scale solar photocatalytic reactor was designed for treating 1 m3 of sulphide wastewater and also for the simultaneous generation of hydrogen. Bench-scale studies were conducted both in the batch recycle and continuous modes under solar irradiation at similar experimental conditions. The maximum of 89.7% conversion was achieved in the continuous mode. The length of the pilot-scale solar photocatalytic reactor was arrived using the design parameters such as volumetric flow rate (Q) (11 x 10(-2) m3/s), inlet concentration of sulphide ion (C(in)) (28 mol/m3), conversion (89.7%) and average mass flow destruction rate (3.488 x 10(-6) mol/m2 s). The treatment cost of the process was estimated to be 6 US$/m3. This process would be suitable for India like sub-tropical country where sunlight is abundantly available throughout the year.

  6. Enhancement of Photo-Current Conversion Efficiency in a CdS/CdSe Quantum-Dot-Sensitized Solar Cell Incorporated with Single-Walled Carbon Nanotubes.

    PubMed

    Park, Hyunjune; Lee, Jongtaek; Park, Taehee; Lee, Sanghun; Yi, Whikun

    2015-02-01

    Cadmium sulfide (CdS) and cadmium selenide (CdSe) are sequentially assembled onto a nanocrystalline TiO2 film to create a quantum-dot (QD)-sensitized solar cell application by a successive ionic layer adsorption and reaction (SILAR) method. The results show that CdS and CdSe QDs have a complementary effect in the performance of light harvest of solar cell. Single-walled carbon nanotubes (SWNTs) are incorporated with a CdS/CdSe QDs solar cell by mixing them with TiC2 film to enhance electron transfer. SWNTs are also sprayed onto CdSe QDs (SWNTs onto CdSe) to apply p+ type properties of SWNTs. Absorbance is increased in a wide wavelength range. In particular, cells having the sprayed SWNTs onto the QDs show a clear increase in absorbance at a low wavelength region. The fill factor of CdS/CdSe QDs solar cell with SWNTs is higher than that without SWNTs, indicating the decrease in loss of electron from TiO2 to QDs. Short-circuit current in a QD-sensitized solar cell having SWNTs on CdSe shows maximum value. Photo-current conversion efficiency of cells is increased in both cell types containing SWNTs at 10~17% compared with pristine cells. We expect that solar cells using SWNTs will affect future energy technology and devices.

  7. Cadmium and renal cancer

    SciTech Connect

    Il'yasova, Dora; Schwartz, Gary G. . E-mail: gschwart@wfubmc.edu

    2005-09-01

    Background: Rates of renal cancer have increased steadily during the past two decades, and these increases are not explicable solely by advances in imaging modalities. Cadmium, a widespread environmental pollutant, is a carcinogen that accumulates in the kidney cortex and is a cause of end-stage renal disease. Several observations suggest that cadmium may be a cause of renal cancer. Methods: We performed a systematic review of the literature on cadmium and renal cancer using MEDLINE for the years 1966-2003. We reviewed seven epidemiological and eleven clinical studies. Results: Despite different methodologies, three large epidemiologic studies indicate that occupational exposure to cadmium is associated with increased risk renal cancer, with odds ratios varying from 1.2 to 5.0. Six of seven studies that compared the cadmium content of kidneys from patients with kidney cancer to that of patients without kidney cancer found lower concentrations of cadmium in renal cancer tissues. Conclusions: Exposure to cadmium appears to be associated with renal cancer, although this conclusion is tempered by the inability of studies to assess cumulative cadmium exposure from all sources including smoking and diet. The paradoxical findings of lower cadmium content in kidney tissues from patients with renal cancer may be caused by dilution of cadmium in rapidly dividing cells. This and other methodological problems limit the interpretation of studies of cadmium in clinical samples. Whether cadmium is a cause of renal cancer may be answered more definitively by future studies that employ biomarkers of cadmium exposure, such as cadmium levels in blood and urine.

  8. Fabrication and characterization of nanowalls CdS/dye sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Abdulelah, Haider; Ali, Basil; Mahdi, M. A.; Hassan, J. J.; Al-Taay, H. F.; Jennings, P.

    2017-06-01

    A microwave assisted chemical bath deposition (MA-CBD) was adopted to fabricate nanowalls CdS nanocrystalline thin film. Nanomaterials (such as nanowalls structure) have attracted significant attention due to their fascinating properties and unique applications, especially in optoelectronic nanodevices. Here we describe the fabrication of dye sensitized solar cells (DSSCs) based nanowalls cadmium sulfide (CdS) nanocrystalline thin films. The surface morphology, crystalline structure, and optical properties of the prepared nanocrystalline thin films are investigated. Rhodamine B, Malachite green, Eosin methylene blue, and Cresyl violet perchlorate dyes are used to fabricate the DSSCS devices. Current-voltage (I-V) characteristics show that the nanowall CdS/Eosin methylene blue device is the highest conversion efficiency of 0.89% under 100 mW/cm2. However, heat treatment of the fabricated solar cells causes significant enhancement in the output of all devices.

  9. Fabrication of silver sulfide thin films for efficient organic solar cells with high short-circuit currents based on double heterojunctions

    NASA Astrophysics Data System (ADS)

    Chen, Chong; Zhai, Yong; Li, Fumin; Yue, Gentian

    2015-12-01

    Efficient solar cells based on Ag2S/P3HT and PCBM/P3HT heterojunctions are fabricated, in which the Ag2S nanoparticles are deposited on ITO glass via a newly developed high-speed rotating thermal decomposition method as an electron selective layer and a light absorption material. The ITO/Ag2S(n)/P3HT:PCBM films have a complementary effect in the light absorption due to the narrow band gap of Ag2S. The Ag2S nanoparticles in the upper layer of Ag2S film form a vertical nanotree-structure after many cycles of Ag2S deposition and lead to the formation of Ag2S/P3HT bulk heterojunction, which facilitates exciton dissociation at the P3HT/Ag2S interfaces and made Ag2S nanocrystals electron-transport materials in the active layers. Moreover, the Ag2S make a contribution to the photocurrent as a light absorber. The maximum power conversion efficiency of 3.21% is achieved for the fabricated ITO/Ag2S(50)/P3HT:PCBM/MoO3/Au solar cell with high short-circuit current, which is 1.13 times the best efficiency (2.84%) of the ITO/dense-TiO2/P3HT:PCBM/MoO3/Au cell made by the high-temperature process and is also much higher than that of reported similar hybrid solar cells based on Ag2S/conjugated polymer heterojunction. The improvement of the efficiency may result from the reduced charge recombination and increased light absorption due to the formation of Ag2S.

  10. Preparation of SnS/CdS Co-sensitized TiO2 Photoelectrodes for Quantum Dots Sensitized Solar Cells

    NASA Astrophysics Data System (ADS)

    Xie, Yu-Long; Song, Ping; Zhao, Su-Qing

    2016-10-01

    TiO2 porous films have been prepared by electrophoresis deposition method, while tin sulfide (SnS) and cadmium sulfide quantum dots (QDs) have been deposited by a simple and inexpensive successive ionic layer adsorption and reaction method. The CdS and SnS QDs modifications expanded the photoresponse range of TiO2 nanoparticles from the ultraviolet region to visible range. Such prepared SnS/CdS/TiO2 films were used as photo-anodes to assemble QDs sensitized solar cells with I-/I3 - liquid electrolyte and Pt-coated fluorine-doped tin oxide glass counter electrode. The best resulting cells had an open circuit voltage of 520 mV, a short circuit current density of 2.972 mA cm-2, a fill factor of 0.61, and with a conversion efficiency of 0.936%.

  11. Retrospective mortality study of cadmium workers: An update

    SciTech Connect

    Thun, M.J.; Schnorr, T.M.; Halperin, W.E.

    1986-02-06

    A retrospective cohort mortality study was conducted among a group of workers exposed to cadmium (7440439), to determine specific causes of death among these workers. The report reviewed the findings of the study and presented additional findings concerning exposures to other hazards at the facility. The study examined the causes of death for 292 cadmium workers who worked at least 2 years at a small facility that recovered cadmium from bag house dust. Exposures included dusts of cadmium-oxide (1306190) and cadmium-sulfide (1306236) and to fumes of cadmium itself. Over a two fold excess of deaths from respiratory cancer was noted among these workers when compared with the general population and over a three fold excess of deaths from prostatic cancer among the men. A follow up of the study cohort revealed that all cause mortality was slightly below that of the United States male population. The Standardized Mortality Ratio for circulatory disease was 65. Deaths due to respiratory cancer were 65% above the number expected. All of the 20 deaths from respiratory cancer were due to cancer of the lung, trachea and bronchus. Deaths due to genitourinary cancer were 35% above expected levels.

  12. Interstellar hydrogen sulfide.

    NASA Technical Reports Server (NTRS)

    Thaddeus, P.; Kutner, M. L.; Penzias, A. A.; Wilson, R. W.; Jefferts, K. B.

    1972-01-01

    Hydrogen sulfide has been detected in seven Galactic sources by observation of a single line corresponding to the rotational transition from the 1(sub 10) to the 1(sub 01) levels at 168.7 GHz. The observations show that hydrogen sulfide is only a moderately common interstellar molecule comparable in abundance to H2CO and CS, but somewhat less abundant than HCN and much less abundant than CO.

  13. Interstellar hydrogen sulfide.

    NASA Technical Reports Server (NTRS)

    Thaddeus, P.; Kutner, M. L.; Penzias, A. A.; Wilson, R. W.; Jefferts, K. B.

    1972-01-01

    Hydrogen sulfide has been detected in seven Galactic sources by observation of a single line corresponding to the rotational transition from the 1(sub 10) to the 1(sub 01) levels at 168.7 GHz. The observations show that hydrogen sulfide is only a moderately common interstellar molecule comparable in abundance to H2CO and CS, but somewhat less abundant than HCN and much less abundant than CO.

  14. Harnessing Sun's Energy with Quantum Dots Based Next Generation Solar Cell.

    PubMed

    Halim, Mohammad A

    2012-12-27

    Our energy consumption relies heavily on the three components of fossil fuels (oil, natural gas and coal) and nearly 83% of our current energy is consumed from those sources. The use of fossil fuels, however, has been viewed as a major environmental threat because of their substantial contribution to greenhouse gases which are responsible for increasing the global average temperature. Last four decades, scientists have been searching for alternative sources of energy which need to be environmentally clean, efficient, cost-effective, renewable, and sustainable. One of the promising sustainable sources of energy can be achieved by harnessing sun energy through silicon wafer, organic polymer, inorganic dye, and quantum dots based solar cells. Among them, quantum dots have an exceptional property in that they can excite multiple electrons using only one photon. These dots can easily be synthesized, processed in solution, and incorporated into solar cell application. Interestingly, the quantum dots solar cells can exceed the Shockley-Queisser limit; however, it is a great challenge for other solar cell materials to exceed the limit. Theoretically, the quantum dots solar cell can boost the power conversion efficiency up to 66% and even higher to 80%. Moreover, in changing the size of the quantum dots one can utilize the Sun's broad spectrum of visible and infrared ranges. This review briefly overviews the present performance of different materials-based solar cells including silicon wafer, dye-sensitized, and organic solar cells. In addition, recent advances of the quantum dots based solar cells which utilize cadmium sulfide/selenide, lead sulfide/selenide, and new carbon dots as light harvesting materials has been reviewed. A future outlook is sketched as to how one could improve the efficiency up to 10% from the current highest efficiency of 6.6%.

  15. Harnessing Sun’s Energy with Quantum Dots Based Next Generation Solar Cell

    PubMed Central

    Halim, Mohammad A.

    2012-01-01

    Our energy consumption relies heavily on the three components of fossil fuels (oil, natural gas and coal) and nearly 83% of our current energy is consumed from those sources. The use of fossil fuels, however, has been viewed as a major environmental threat because of their substantial contribution to greenhouse gases which are responsible for increasing the global average temperature. Last four decades, scientists have been searching for alternative sources of energy which need to be environmentally clean, efficient, cost-effective, renewable, and sustainable. One of the promising sustainable sources of energy can be achieved by harnessing sun energy through silicon wafer, organic polymer, inorganic dye, and quantum dots based solar cells. Among them, quantum dots have an exceptional property in that they can excite multiple electrons using only one photon. These dots can easily be synthesized, processed in solution, and incorporated into solar cell application. Interestingly, the quantum dots solar cells can exceed the Shockley-Queisser limit; however, it is a great challenge for other solar cell materials to exceed the limit. Theoretically, the quantum dots solar cell can boost the power conversion efficiency up to 66% and even higher to 80%. Moreover, in changing the size of the quantum dots one can utilize the Sun’s broad spectrum of visible and infrared ranges. This review briefly overviews the present performance of different materials-based solar cells including silicon wafer, dye-sensitized, and organic solar cells. In addition, recent advances of the quantum dots based solar cells which utilize cadmium sulfide/selenide, lead sulfide/selenide, and new carbon dots as light harvesting materials has been reviewed. A future outlook is sketched as to how one could improve the efficiency up to 10% from the current highest efficiency of 6.6%. PMID:28348320

  16. Embedded vertically aligned cadmium telluride nanorod arrays grown by one-step electrodeposition for enhanced energy conversion efficiency in three-dimensional nanostructured solar cells.

    PubMed

    Wang, Jun; Liu, Shurong; Mu, Yannan; Liu, Li; A, Runa; Yang, Jiandong; Zhu, Guijie; Meng, Xianwei; Fu, Wuyou; Yang, Haibin

    2017-11-01

    Vertically aligned CdTe nanorods (NRs) arrays are successfully grown by a simple one-step and template-free electrodeposition method, and then embedded in the CdS window layer to form a novel three-dimensional (3D) heterostructure on flexible substrates. The parameters of electrodeposition such as deposition potential and pH of the solution are varied to analyze their important role in the formation of high quality CdTe NRs arrays. The photovoltaic conversion efficiency of the solar cell based on the 3D heterojunction structure is studied in detail. In comparison with the standard planar heterojunction solar cell, the 3D heterojunction solar cell exhibits better photovoltaic performance, which can be attributed to its enhanced optical absorption ability, increased heterojunction area and improved charge carrier transport. The better photoelectric property of the 3D heterojunction solar cell suggests great application potential in thin film solar cells, and the simple electrodeposition process represents a promising technique for large-scale fabrication of other nanostructured solar energy conversion devices. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Synthesis of optimized indium phosphide/zinc sulfide core/shell nanocrystals and titanium dioxide nanotubes for quantum dot sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Lee, Seungyong

    Synthesis of InP/ZnS core/shell nanocrystals and TiO 2 nanotubes and the optimization study to couple them together were explored for quantum dot sensitized solar cells. Its intrinsic nontoxicity makes the direct band gap InP/ZnS core/shell be one of the most promising semiconductor nanocrystals for optoelectric applications, with the advantage of tuning the optical absorption range in the desired solar spectrum region. Highly luminescent and monodisperse InP/ZnS nanocrystals were synthesized in a non-coordinating solvent. By varying the synthesis scheme, different size InP/ZnS nanocrystals with emission peaks ranging from 520 nm to 620 nm were grown. For the purpose of ensuring air stability, a ZnS shell was grown. The ZnS shell improves the chemical stability in terms of oxidation prevention. Transmission electron microscopy (TEM) image shows that the nanocrystals are highly crystalline and monodisperse. Free-standing TiO2 nanotubes were produced by an anodization method using ammonium fluoride. The free-standing nanotubes were formed under the condition that the chemical dissolution speed associated with fluoride concentration was faster than the speed of Ti oxidation. Highly ordered free-standing anatase form TiO2 nanotubes, which are transformed by annealing at the optimized temperature, are expected to be ideal for coupling with the prepared InP/ZnS nanocrystals. Electrophoretic deposition was carried out to couple the InP/ZnS nanocrystals with the TiO2 nanotubes. Under the adjusted applied voltage condition, the current during the electrophoretic deposition decreased continuously with time. The amount of the deposited nanocrystals was estimated by calculation and the evenly deposited nanocrystals on the TiO2 nanotubes were observed by TEM.

  18. Cadmium in tobacco

    SciTech Connect

    Yue, L. )

    1992-03-01

    The present study was conducted to determine the cadmium level in tobacco planted in five main tobacco-producing areas, a cadmium polluted area, and in cigarettes produced domestically (54 brands). The results indicate that average cadmium content in tobacco was 1.48 (0.10-4.95 mg/kg), which was similar to that of Indian tobacco (1.24 mg/kg), but the cadmium of tobacco produced in the cadmium polluted area was quite high (8.60 mg/kg). The average cigarette cadmium was 1.05 micrograms/g (with filter tip) and 1.61 micrograms/g (regular cigarette). Therefore special attention should be paid to the soil used in planting tobacco.

  19. Cadmium - A metallohormone?

    SciTech Connect

    Byrne, Celia; Divekar, Shailaja D.; Storchan, Geoffrey B.; Parodi, Daniela A.; Martin, Mary Beth

    2009-08-01

    Cadmium is a heavy metal that is often referred to as the metal of the 20th century. It is widely used in industry principally in galvanizing and electroplating, in batteries, in electrical conductors, in the manufacture of alloys, pigments, and plastics, and in the stabilization of phosphate fertilizers. As a byproduct of smelters, cadmium is a prevalent environmental contaminant. In the general population, exposure to cadmium occurs primarily through dietary sources, cigarette smoking, and, to a lesser degree, drinking water. Although the metal has no known physiological function, there is evidence to suggest that the cadmium is a potent metallohormone. This review summarizes the increasing evidence that cadmium mimics the function of steroid hormones, addresses our current understanding of the mechanism by which cadmium functions as a hormone, and discusses its potential role in development of the hormone dependent cancers.

  20. Cadmium - a metallohormone?

    PubMed Central

    Byrne, Celia; Divekar, Shailaja D.; Storchan, Geoffrey B.; Parodi, Daniela A.; Martin, Mary Beth

    2009-01-01

    Cadmium is a heavy metal that is often referred to as the metal of the 20th Century. It is widely used in industry principally in galvanizing and electroplating, in batteries, in electrical conductors, in the manufacture of alloys, pigments, and plastics, and in the stabilization of phosphate fertilizers. As a byproduct of smelters, cadmium is a prevalent environmental contaminant. In the general population, exposure to cadmium occurs primarily through dietary sources, cigarette smoking, and, to a lesser degree, drinking water. Although the metal has no known physiological function, there is evidence to suggest that the cadmium is a potent metallohormone. This review summarizes the increasing evidence that cadmium mimics the function of steroid hormones, addresses our current understanding of the mechanism by which cadmium functions as a hormone, and discusses its potential role in development of the hormone dependent cancers. PMID:19362102

  1. Dip coated nanocrystalline CdZnS thin films for solar cell application

    SciTech Connect

    Dongre, J. K. Chaturvedi, Mahim; Patil, Yuvraj; Sharma, Sandhya; Jain, U. K.

    2015-07-31

    Nanocrystalline cadmium sulfide (CdS) and zinc cadmium sulfide (ZnCdS) thin films have been grown via simple and low cost dip coating technique. The prepared films are characterized by X-ray diffraction (XRD), atomic force microscopic (AFM) and UV-VIS spectrophotometer techniques to reveal their structural, morphological and optical properties. XRD shows that both samples grown have zinc blende structure. The grain size is calculated as 6.2 and 8 nm using Scherrer’s formula. The band gap value of CdS and CdZnS film is estimated to be 2.58 and 2.69 eV respectively by UV-vis spectroscopy. Photoelectrochemical (PEC) investigations are carried out using cell configuration as n-CdZnS/(1M NaOH + 1M Na2S + 1M S)/C. The photovoltaic output characteristic is used to calculate fill-factor (FF) and solar conversion efficiency (η)

  2. Investigation of cadmium resistance in an Alcaligenes sp.

    PubMed Central

    McEntee, J D; Woodrow, J R; Quirk, A V

    1986-01-01

    The mechanisms of metal resistance of a cadmium-resistant Alcaligenes sp. were studied. Growth in a defined medium was unaffected by cadmium at concentrations up to 0.1 mM, while at concentrations up to 2.5 mM, growth occurred after an extended lag phase. The increase in length of the lag phase was abolished by repeated subculturing at these higher concentrations. However, subculture in the absence of cadmium reversed the adaptation process. Plasmid DNA was not detected in adapted cells, suggesting that adaptation is not plasmid mediated. Increased sulfide production in response to cadmium was observed, although the levels were too low to account fully for cadmium resistance. Adaptation of cells to cadmium resulted in the appearance of a major new membrane protein (molecular weight, 34,500) whose presence was not dependent upon the method of membrane preparation. This protein was induced at cadmium concentrations of 0.1 mM and above, but below this level the protein was absent. The onset of growth at concentrations above 0.1 mM was coincident with the appearance of this protein, which was also induced by zinc (0.4 mM) but not by manganese or nickel. The protein was only solubilized by a sodium dodecyl sulfate-2-mercaptoethanol mixture. Similar solubility properties were shown by a second major membrane protein (molecular weight, 33,000). These two proteins proved to be similar by peptide-mapping experiments and amino acid analysis. The appearance of the 34,500-molecular-weight protein and its possible role in cadmium resistance are discussed. Images PMID:3963810

  3. Solid state, transparent, cadmium sulfide-polymer nanocomposites

    NASA Astrophysics Data System (ADS)

    Kothurkar, Nikhil K.

    This dissertation deals with the preparation and characterization of solid state, transparent CdS-polymer nanocomposites for potential applications in optical limiting, lenses and photovoltaics. The focus of this research was controlling CdS aggregation to obtain 1 mm thick, films with a transmittance >85%. CdS-polysulfone nanocomposites gave transparent sols using thiol-capping agents however solid films obtained, were translucent to opaque. CdS-epoxy nanocomposites gave 1 mm thick films with >85% transmittance. Oligomeric polyoxypropylene diamine stabilizers were used to shield the inter particle forces and increase the viscosity of the medium to give air stable sols. Films were obtained by curing the CdS sols with an epoxy resin system. The band edge of the nanocomposites showed a shoulder corresponding to the absorption from the CdS particles. A majority of small amorphous and non-stoichiometric (richer in Cd) particles <5 nm were observed in TEM micrographs. Relatively fewer CdS aggregates in the range of tens to hundreds of nanometers were also detected. Aggregates were generally more numerous in films as compared to sols. The two-photon absorption coefficient of the CdS particles in the films showed a 30-fold reduction compared to bulk CdS. This was attributed to the lack of crystallinity of particles. The films were stable up to 300°C. CdS aggregation in the CdS-epoxy system depends on a number of factors including temperature, stabilizer concentration, stabilizer molar mass and US concentration. Effective aggregation control yields transparent films. Factors affecting the band edge and transparency of the films were detected and regression models were fitted to the data. Temperature, stabilizer concentration and CdS concentration had significant effects on the band edge and transparency. Interactions between temperature-stabilizer concentration and temperature-CdS concentration had significant effects on the band edge. Band edge tunability with temperature was demonstrated. An attempt to estimate the particle size from the band edge was made but owing absence of any suitable theoretical models, an accurate estimate was not possible. However a rough estimate was provided. High concentration CdS-epoxy thin and thick films containing up to 21% US were synthesized using two different methods. High transparency of about 85% was obtained in some of them.

  4. Crystalline phase transformation of colloidal cadmium sulfide nanocrystals

    NASA Astrophysics Data System (ADS)

    Ghali, M.; Eissa, A. M.; Mosaad, M. M.

    2017-03-01

    In this paper, we give a microscopic view concerning influence of the growth conditions on the physical properties of nanocrystals (NCs) thin films made of CdS, prepared using chemical bath deposition CBD technique. We show a crystalline phase transformation of CdS NCs from hexagonal wurtzite (W) structure to cubic zincblende (ZB) when the growth conditions change, particularly the solution pH values. This effect was confirmed using X-ray diffraction (XRD), transmission electron microscopy (TEM), optical absorption and photoluminescence (PL) measurements. The optical absorption spectra allow calculation of the bandgap value, Eg, where significant increase ˜200 meV in the CdS bandgap when transforming from Hexagonal to Cubic phase was found.

  5. TEMPERATURE DEPENDENCE OF LINE STRUCTURE OF CADMIUM SULFIDE EDGE EMISSION

    DTIC Science & Technology

    The temperature dependence of the line structure in Cds edge emission stimulated by UV light was investigated from 4.2 K to 367 K. The spectral... dependence of the primary line groups is a linear function of temperature above 220 K with coefficients of change of 1.27 and 1.8 Angstroms degree K for the...lines observed. Below 220 K the dependence departs from linearity and approaches its limiting value more rapidly with decreasing temperature

  6. Sulfidation of silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Levard, C.; Michel, F. M.; Brown, G. E.

    2010-12-01

    Rapid development of nanotechnologies that exploit the properties of silver nanoparticles (Ag-NPs) raises questions concerning the impact of Ag on the environment. Ag-NPs are currently among the most widely used in the nanotechnology industry and the amount released into the environment is expected to increase along with production (1). When present in geochemical systems, Ag-NPs may undergo a variety of changes due to varying redox, pH, and chemical conditions. Expected changes range from surface modification (e.g., oxidation, sulfidation, chloridation etc.) to complete dissolution and re-precipitation. In this context, the focus of our work is on understanding the behavior of synthetic Ag-NPs with different particle sizes under varying conditions relevant to the environment. Sulfidation of Ag-NPs is of particular interest since it among the processes most likely to occur in aqueous systems, in particular under reducing conditions. Three sizes of Ag-NPs coated with polyvinyl pyrrolidone were produced using the polyol process (2) (7 ±1; 20 ±4, and 40 ±9 nm). Batch solutions containing the different Ag-NPs were subsequently reacted with Na2S solutions of different concentrations. The sulfidation process was followed step-wise for 24 hours and the corrosion products formed were characterized by electron microscopy (TEM/SEM), diffraction (XRD), and photo-electron spectroscopy (XPS). Surface charge (pHPZC) of the products formed during this process was also measured, as were changes in solubility and reactivity. Based on experimental observations we infer that the sulfidation process is the result of dissolution-precipitation and find that: (i) acanthite (Ag2S) is formed as a corrosion product; (ii) Ag-NPs aggregation increased with sulfidation rate; (iii) pHPZC increases with the rate of sulfidation; and (iv) the solubility of the corrosion products formed from sulfidation appears lower than that of non-sulfidated Ag-NPs. We observe size-dependent differences in

  7. Removal of heavy metals by sulfide precipitation in the presence of complexing agents

    SciTech Connect

    Ku, Y.

    1986-01-01

    Heavy metal removals and particle size distributions were presented for both hydroxide precipitation and sulfide precipitation of zinc, cadmium, copper, and nickel in the presence of various complexing agents. Both batch and continuous experiments were performed for synthetic and actual metal-containing wastewaters. Metal concentrations complexing agent concentrations, sulfide dosages, pH levels of the solutions, and reaction or residence times were varied to determine the reaction kinetics. Sulfide precipitation always achieved lower residual metal concentrations than the corresponding hydroxide precipitation. The presence of strong complexing agents severely inhibited the removal of heavy metal by the precipitation process. Weak complexing agents exhibited little effect on the chemical equilibria for both hydroxide and sulfide precipitation systems. Weak complexing agents did affect the particle size distribution through a nucleation/growth inhibition, general forming smaller particles.

  8. SULFIDE METHOD PLUTONIUM SEPARATION

    DOEpatents

    Duffield, R.B.

    1958-08-12

    A process is described for the recovery of plutonium from neutron irradiated uranium solutions. Such a solution is first treated with a soluble sullide, causing precipitation of the plutoniunn and uraniunn values present, along with those impurities which form insoluble sulfides. The precipitate is then treated with a solution of carbonate ions, which will dissolve the uranium and plutonium present while the fission product sulfides remain unaffected. After separation from the residue, this solution may then be treated by any of the usual methods, such as formation of a lanthanum fluoride precipitate, to effect separation of plutoniunn from uranium.

  9. The photoluminescence and phase composition of lead sulphide-cadmium sulphide layers obtained by chemical bath deposition

    NASA Astrophysics Data System (ADS)

    Maraeva, E. V.; Shupta, A. A.; Bobkov, A. A.; Levitskii, V. S.; Maximov, A. I.; Moshnikov, V. A.

    2016-08-01

    The study concerns optical properties and phase composition studies of the layers based on cadmium sulfide-lead sulfide synthesized by the hydro-chemical deposition. The presence of two peaks in the photoluminescence spectra presumably correspond to two different CdS modifications, i.e. the cubic structure of zinc blende and hexagonal structure (wurtzite type). X-ray phase analysis (XRPA) confirmes the presence of both types of crystallites.

  10. Cadmium in zinc deposits: Economic geology of a polluting element

    SciTech Connect

    Schwartz, M.O.

    2000-05-01

    The chief host of cadmium in zinc deposits is sphalerite, the cadmium content of which depends on the type of deposit. Sphalerite from Mississippi Valley-type (MVT) deposits has high cadmium concentrations whereas sphalerite from exhalative deposits has low cadmium concentrations. The Cd content of sphalerite depends on the Cd/Zn ratio, ligand activities, and temperature of the ore-forming fluids. The combined effect of variation of temperature, pH, total activity of reduced sulfur, and activity of Cl{sup {minus}} cannot by itself account for either Cd depletion (exhalative deposits) or Cd enrichment (MVT deposits). Variations in the Cd/Zn ratio of the fluid have a significant effect in determining that of sphalerite. Basinal brines, which can be considered to be the recent equivalents of MVT fluids, have high Cd/Zn ratios, and active exhalative systems are characterized by low Cd/Zn ratios. Probably the differences in sphalerite composition between the different deposit types are less a function of temperature and ligand activities than Cd/Zn ratio of the ore-forming fluids. In the hydrothermal environment, the Cd/Zn ratio is generally not high enough to allow crystallization of cadmium sulfides (greenockite or hawleyite). The abundance of greenockite in the supergene alteration zone of hydrothermal zinc deposits can be explained on the basis of Zn scavenging by crystallizing smithsonite.

  11. Wet oxidation of oil-bearing sulfide wastes

    SciTech Connect

    Miller, R.L.; Hotz, N.J.

    1991-01-01

    Oil-bearing metal sulfide sludges produced in treatment of an industrial wastewater, which includes plating wastes, have yielded to treatment by electrooxidation and hydrogen peroxide processes. The oxidation can be controlled to be mild enough to avoid decomposition of the organic phase while oxidizing the sulfides to sulfates. The pH is controlled to near neutral conditions where iron, aluminum and chromium(III) precipitate as hydrous oxides. Other metals, such as lead and barium, may be present as sulfate precipitates with limited solubility, while metals such as nickel and cadmium would be present as complexed ions in a sulfate solution. The oxidations were found to proceed smoothly, without vigorous reaction; heat liberation was minimal. 2 refs., 12 figs.

  12. Synthesis and photovoltaic application of coper (I) sulfide nanocrystals

    SciTech Connect

    Wu, Yue; Wadia, Cyrus; Ma, Wanli; Sadtler, Bryce; Alivisatos, A.Paul

    2008-06-24

    We present the rational synthesis of colloidal copper(I) sulfide nanocrystals and demonstrate their application as an active light absorbing component in combination with CdS nanorods to make a solution-processed solar cell with 1.6percent power conversion efficiency on both conventional glass substrates and flexible plastic substrates with stability over a 4 month testing period.

  13. Solar heat pump

    NASA Astrophysics Data System (ADS)

    Hermanson, R.

    Brief discussions of the major components of a solar powered, chemical ground source heat pump are presented. The components discussed are the solar collectors and the chemical heat storage battery. Sodium sulfide is the medium used for heat storage. Catalog information which provides a description of all of the heat pump systems is included.

  14. Sulfidation kinetics of silver nanoparticles reacted with metal sulfides.

    PubMed

    Thalmann, Basilius; Voegelin, Andreas; Sinnet, Brian; Morgenroth, Eberhard; Kaegi, Ralf

    2014-05-06

    Recent studies have documented that the sulfidation of silver nanoparticles (Ag-NP), possibly released to the environment from consumer products, occurs in anoxic zones of urban wastewater systems and that sulfidized Ag-NP exhibit dramatically reduced toxic effects. However, whether Ag-NP sulfidation also occurs under oxic conditions in the absence of bisulfide has not been addressed, yet. In this study we, therefore, investigated whether metal sulfides that are more resistant toward oxidation than free sulfide, could enable the sulfidation of Ag-NP under oxic conditions. We reacted citrate-stabilized Ag-NP of different sizes (10-100 nm) with freshly precipitated and crystalline CuS and ZnS in oxygenated aqueous suspensions at pH 7.5. The extent of Ag-NP sulfidation was derived from the increase in dissolved Cu(2+) or Zn(2+) over time and linked with results from X-ray absorption spectroscopy (XAS) analysis of selected samples. The sulfidation of Ag-NP followed pseudo first-order kinetics, with rate coefficients increasing with decreasing Ag-NP diameter and increasing metal sulfide concentration and depending on the type (CuS and ZnS) and crystallinity of the reacting metal sulfide. Results from analytical electron microscopy revealed the formation of complex sulfidation patterns that seemed to follow preexisting subgrain boundaries in the pristine Ag-NP. The kinetics of Ag-NP sulfidation observed in this study in combination with reported ZnS and CuS concentrations and predicted Ag-NP concentrations in wastewater and urban surface waters indicate that even under oxic conditions and in the absence of free sulfide, Ag-NP can be transformed into Ag2S within a few hours to days by reaction with metal sulfides.

  15. Zinc sulfide liquefaction catalyst

    DOEpatents

    Garg, Diwakar

    1984-01-01

    A process for the liquefaction of carbonaceous material, such as coal, is set forth wherein coal is liquefied in a catalytic solvent refining reaction wherein an activated zinc sulfide catalyst is utilized which is activated by hydrogenation in a coal derived process solvent in the absence of coal.

  16. Nonstoichiometry of crystalline cadmium selenide

    SciTech Connect

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

    1987-08-01

    A highly sensitive physicochemical method is developed for determining the cadmium concentration (10/sup -5/ at. % for a 10 g sample weight), dissolved in cadmium selenide. The nonstoichiometry of cadmium selenide crystals is studied after high-temperature annealing at 870-1370/sup 0/K in cadmium vapor. For the first time, it is discovered that in the investigated crystals the dissolved cadmium exists primarily in the form of electrically neutral defects, which are presumably clusters of selenium vacancies with low mobility.

  17. Influences of dietary uptake and reactive sulfides on metal bioavailability from aquatic sediments

    USGS Publications Warehouse

    Lee, B.-G.

    2000-01-01

    Understanding how animals are exposed to the large repository of metal pollutants in aquatic sediments is complicated and is important in regulatory decisions. Experiments with four types of invertebrates showed that feeding behavior and dietary uptake control bioaccumulation of cadmium, silver, nickel, and zinc. Metal concentrations in animal tissue correlated with metal concentrations extracted from sediments, but not with metal in porewater, across a range of reactive sulfide concentrations, from 0.5 to 30 micromoles per gram. These results contradict the notion that metal bioavailability in sediments is controlled by geochemical equilibration of metals between porewater and reactive sulfides, a proposed basis for regulatory criteria for metals.

  18. Influences of dietary uptake and reactive sulfides on metal bioavailability from aquatic sediments.

    PubMed

    Lee, B G; Griscom, S B; Lee, J S; Choi, H J; Koh, C H; Luoma, S N; Fisher, N S

    2000-01-14

    Understanding how animals are exposed to the large repository of metal pollutants in aquatic sediments is complicated and is important in regulatory decisions. Experiments with four types of invertebrates showed that feeding behavior and dietary uptake control bioaccumulation of cadmium, silver, nickel, and zinc. Metal concentrations in animal tissue correlated with metal concentrations extracted from sediments, but not with metal in porewater, across a range of reactive sulfide concentrations, from 0.5 to 30 micromoles per gram. These results contradict the notion that metal bioavailability in sediments is controlled by geochemical equilibration of metals between porewater and reactive sulfides, a proposed basis for regulatory criteria for metals.

  19. Enhanced performance of cadmium selenide quantum dot-sensitized solar cells by incorporating long afterglow europium, dysprosium co-doped strontium aluminate phosphors.

    PubMed

    Sun, Hengchao; Pan, Likun; Piao, Xianqing; Sun, Zhuo

    2014-02-15

    CdSe quantum dot-sensitized solar cells based on an efficient bifunctional structured layer composed of long afterglow SrAl2O4:Eu,Dy phosphors on top of a transparent layer of nanocrystalline TiO2 were fabricated and their photovoltaic performances were investigated. The results show that a high power conversion efficiency of 1.22% is achieved for the cell with SrAl2O4:Eu,Dy at one sun illumination (AM 1.5 G, 100 mW cm(-2)), which is an increase of 48% compared to the cell without SrAl2O4:Eu,Dy (0.82%). After one sun illumination for 1 min and subsequent turn off of the light source, the cell with SrAl2O4:Eu,Dy still shows an efficiency of 0.04% under dark condition due to the irradiation by the long persistent light from SrAl2O4:Eu,Dy. The present strategy should provide a possibility to fulfill the operation of solar cells even in the dark.

  20. Polymer/Nanocrystal Hybrid Solar Cells: Influence of Molecular Precursor Design on Film Nanomorphology, Charge Generation and Device Performance.

    PubMed

    MacLachlan, Andrew J; Rath, Thomas; Cappel, Ute B; Dowland, Simon A; Amenitsch, Heinz; Knall, Astrid-Caroline; Buchmaier, Christine; Trimmel, Gregor; Nelson, Jenny; Haque, Saif A

    2015-01-01

    In this work, molecular tuning of metal xanthate precursors is shown to have a marked effect on the heterojunction morphology of hybrid poly(3-hexylthiophene-2,5-diyl) (P3HT)/CdS blends and, as a result, the photochemical processes and overall performance of in situ fabricated hybrid solar cells. A series of cadmium xanthate complexes is synthesized for use as in situ precursors to cadmium sulfide nanoparticles in hybrid P3HT/CdS solar cells. The formation of CdS domains is studied by simultaneous GIWAXS (grazing incidence wide-angle X-ray scattering) and GISAXS (grazing incidence small-angle X-ray scattering), revealing knowledge about crystal growth and the formation of different morphologies observed using TEM (transmission electron microscopy). These measurements show that there is a strong relationship between precursor structure and heterojunction nanomorphology. A combination of TAS (transient absorption spectroscopy) and photovoltaic device performance measurements is used to show the intricate balance required between charge photogeneration and percolated domains in order to effectively extract charges to maximize device power conversion efficiencies. This study presents a strong case for xanthate complexes as a useful route to designing optimal heterojunction morphologies for use in the emerging field of hybrid organic/inorganic solar cells, due to the fact that the nanomorphology can be tuned via careful design of these precursor materials.

  1. Polymer/Nanocrystal Hybrid Solar Cells: Influence of Molecular Precursor Design on Film Nanomorphology, Charge Generation and Device Performance

    PubMed Central

    MacLachlan, Andrew J; Rath, Thomas; Cappel, Ute B; Dowland, Simon A; Amenitsch, Heinz; Knall, Astrid-Caroline; Buchmaier, Christine; Trimmel, Gregor; Nelson, Jenny; Haque, Saif A

    2015-01-01

    In this work, molecular tuning of metal xanthate precursors is shown to have a marked effect on the heterojunction morphology of hybrid poly(3-hexylthiophene-2,5-diyl) (P3HT)/CdS blends and, as a result, the photochemical processes and overall performance of in situ fabricated hybrid solar cells. A series of cadmium xanthate complexes is synthesized for use as in situ precursors to cadmium sulfide nanoparticles in hybrid P3HT/CdS solar cells. The formation of CdS domains is studied by simultaneous GIWAXS (grazing incidence wide-angle X-ray scattering) and GISAXS (grazing incidence small-angle X-ray scattering), revealing knowledge about crystal growth and the formation of different morphologies observed using TEM (transmission electron microscopy). These measurements show that there is a strong relationship between precursor structure and heterojunction nanomorphology. A combination of TAS (transient absorption spectroscopy) and photovoltaic device performance measurements is used to show the intricate balance required between charge photogeneration and percolated domains in order to effectively extract charges to maximize device power conversion efficiencies. This study presents a strong case for xanthate complexes as a useful route to designing optimal heterojunction morphologies for use in the emerging field of hybrid organic/inorganic solar cells, due to the fact that the nanomorphology can be tuned via careful design of these precursor materials. PMID:25866496

  2. Cadmium sulfide-copper sulfide heterojunction cell research. Annual report, September 1, 1979-August 31, 1980

    SciTech Connect

    1980-12-01

    The primary goal of this program, increasing the conversion efficiency of a thin-film cell based on CdS/Cu/sub 2/S, has been achieved. A number of (CdZn)S/Cu/sub 2/S cells have been made with conversion efficiencies in excess of 10% when tested in collimated sunlight. The highest efficiency achieved was 10.2% for a cell with 16% Zinc which had the following parameters; V/sub oc/ = 0.60V, J/sub sc/ = 22.8 mA/cm/sup 2/ (pro-rated to 100 mW/cm/sup 2/) FF = 74.9%. Further improvement in the performance of CdS/Cu/sub 2/S cells beyond the previously reported 9.2%, was found to be limited by deficiencies in the fundamental knowledge and control of the Cu/sub 2/S layer. A number of process changes in the production of CdS/Cu/sub 2/S cells have been explored and are reported on. Transient capacitance measurements on CdS/Cu/sub 2/S cells and further development of an integral encapsulation are also reported.

  3. Cadmium sulfide-copper sulfide heterojunction cell research. Quarterly progress report, March 1-May 31, 1980

    SciTech Connect

    1980-11-01

    A complete statistical analysis of the yield of CdS/Cu/sub 2/S cells produced by the standard processes is presented. Progress has been made on producing (CdZn)S films with the appropriate properties to yield high efficiency cells. Further studies of capacitance and transient-capacitance are reported. Defects in electron beam deposited glass are shown to be responsible for lack of effective sealing against atmospheric attack.

  4. Electrochemical behavior of silver sulfide

    SciTech Connect

    Drouven, B.U.E.

    1982-01-01

    The electrochemical behavior of silver sulfide in sulfuric acid as well as in nitric acid was studied using electrodes made from synthetic silver sulfide. The primary techniques used were potentiostatic, potentiodynamic, galvanostatic and corrosion cell experiments. The cathodic reaction of silver sulfide produces silver and hydrogen sulfide. This reaction mechanism is a sequential two step charge transfer involving a single electron in each step. Silver ions are produced from silver sulfide upon applying an anodic potential. The dissolution rate of silver sulfide can be so high that the formation of silver sulfate occurs which partially covers the silver sulfide surface and inhibits a further rate increase. The sulfur from the silver sulfide will be oxidized at low overpotentials to elemental sulfur; at high overpotentials, the oxidation to sulfate or bisulfate is observed. The results suggest that the catalysis of chalcopyrite by the addition of silver ions is caused by the formation and subsequent dissolution of silver sulfide leaving a porous layer behind. The understanding of the reaction mechanism of silver sulfide dissolution and its optimization will significantly improve the economic evaluation of industrial processes using the catalyzed leaching of chalcopyrite. The present knowledge of the catalysis indicates that other ions may be substituted for silver ions which would increase the feasibility of hydrometallurgical processes.

  5. Sulfide detoxification in plant mitochondria.

    PubMed

    Birke, Hannah; Hildebrandt, Tatjana M; Wirtz, Markus; Hell, Rüdiger

    2015-01-01

    In contrast to animals, which release the signal molecule sulfide in small amounts from cysteine and its derivates, phototrophic eukaryotes generate sulfide as an essential intermediate of the sulfur assimilation pathway. Additionally, iron-sulfur cluster turnover and cyanide detoxification might contribute to the release of sulfide in mitochondria. However, sulfide is a potent inhibitor of cytochrome c oxidase in mitochondria. Thus, efficient sulfide detoxification mechanisms are required in mitochondria to ensure adequate energy production and consequently survival of the plant cell. Two enzymes have been recently described to catalyze sulfide detoxification in mitochondria of Arabidopsis thaliana, O-acetylserine(thiol)lyase C (OAS-TL C), and the sulfur dioxygenase (SDO) ethylmalonic encephalopathy protein 1 (ETHE1). Biochemical characterization of sulfide producing and consuming enzymes in mitochondria of plants is fundamental to understand the regulatory network that enables mitochondrial sulfide homeostasis under nonstressed and stressed conditions. In this chapter, we provide established protocols to determine the activity of the sulfide releasing enzyme β-cyanoalanine synthase as well as sulfide-consuming enzymes OAS-TL and SDO. Additionally, we describe a reliable and efficient method to purify OAS-TL proteins from plant material. © 2015 Elsevier Inc. All rights reserved.

  6. High efficiency cadmium telluride and zinc telluride based thin-film solar cells. Annual subcontract report, 1 March 1990--28 February 1992

    SciTech Connect

    Rohatgi, A.; Sudharsanan, R.; Ringel, S.A.; Chou, H.C.

    1992-10-01

    This report describes work to improve the basic understanding of CdTe and ZnTe alloys by growing and characterizing these films along with cell fabrication. The major objective was to develop wide-band-gap (1.6--1.8 eV) material for the top cell, along with compatible window material and transparent ohmic contacts, so that a cascade cell design can be optimized. Front-wall solar cells were fabricated with a glass/SnO{sub 2}/CdS window, where the CdS film is thin to maximize transmission and current. Wide-band-gap absorber films (E{sub g} = 1.75 eV) were grown by molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD) techniques, which provided excellent control for tailoring the film composition and properties. CdZnTe films were grown by both MBE and MOCVD. All the as-grown films were characterized by several techniques (surface photovoltage spectroscopy, Auger electron spectroscopy (AES), and x-ray photoelectron spectroscopy (XPS)) for composition, bulk uniformity, thickness, and film and interface quality. Front-wall-type solar cells were fabricated in collaboration with Ametek Materials Research Laboratory using CdTe and CdZnTe polycrystalline absorber films. The effects of processing on ternary film were studied by AES and XPS coupled with capacitance voltage and current voltage measurements as a function of temperature. Bias-dependent spectral response and electrical measurements were used to test some models in order to identify and quantify dominant loss mechanisms.

  7. Geothermal hydrogen sulfide removal

    SciTech Connect

    Urban, P.

    1981-04-01

    UOP Sulfox technology successfully removed 500 ppM hydrogen sulfide from simulated mixed phase geothermal waters. The Sulfox process involves air oxidation of hydrogen sulfide using a fixed catalyst bed. The catalyst activity remained stable throughout the life of the program. The product stream composition was selected by controlling pH; low pH favored elemental sulfur, while high pH favored water soluble sulfate and thiosulfate. Operation with liquid water present assured full catalytic activity. Dissolved salts reduced catalyst activity somewhat. Application of Sulfox technology to geothermal waters resulted in a straightforward process. There were no requirements for auxiliary processes such as a chemical plant. Application of the process to various types of geothermal waters is discussed and plans for a field test pilot plant and a schedule for commercialization are outlined.

  8. Biotreatment of refinery spent sulfidic caustics

    SciTech Connect

    Sublette, K.L.; Rajganesh, B.; Woolsey, M.; Plato, A.

    1995-12-31

    Caustics are used in petroleum refinering to remove hydrogen sulfide from various hydrocarbon streams. Spent sulfidic caustics from two Conoco refineries have been successfully biotreated on bench and pilot scale, resulting in neutralization and removal of active sulfides. Sulfides were completely oxidized to sulfate by Thiobacillus denitrificans. Microbial oxidation of sulfide produced acid, which at least partially neutralized the caustic.

  9. Mineral commodity profiles: Cadmium

    USGS Publications Warehouse

    Butterman, W.C.; Plachy, Jozef

    2004-01-01

    Overview -- Cadmium is a soft, low-melting-point metal that has many uses. It is similar in abundance to antimony and bismuth and is the 63d element in order of crustal abundance. Cadmium is associated in nature with zinc (and, less closely, with lead and copper) and is extracted mainly as a byproduct of the mining and processing of zinc. In 2000, it was refined in 27 countries, of which the 8 largest accounted for two-thirds of world production. The United States was the third largest refiner after Japan and China. World production in 2000 was 19,700 metric tons (t) and U.S. production was 1,890 t. In the United States, one company in Illinois and another in Tennessee refined primary cadmium. A Pennsylvania company recovered cadmium from scrap, mainly spent nickel-cadmium (NiCd) batteries. The supply of cadmium in the world and in the United States appears to be adequate to meet future industrial needs; the United States has about 23 percent of the world reserve base.

  10. Suicide with hydrogen sulfide.

    PubMed

    Sams, Ralph Newton; Carver, H Wayne; Catanese, Charles; Gilson, Thomas

    2013-06-01

    This presentation will address the recent rise of suicide deaths resulting from the asphyxiation by hydrogen sulfide (H2S) gas.Hydrogen sulfide poisoning has been an infrequently encountered cause of death in medical examiner practice. Most H2S deaths that have been reported occurred in association with industrial exposure.More recently, H2S has been seen in the commission of suicide, particularly in Japan. Scattered reports of this phenomenon have also appeared in the United States.We have recently observed 2 intentional asphyxial deaths in association with H2S. In both cases, the decedents committed suicide in their automobiles. They generated H2S by combining a sulfide-containing tree spray with toilet bowl cleaner (with an active ingredient of hydrogen chloride acid). Both death scenes prompted hazardous materials team responses because of notes attached to the victims' car windows indicating the presence of toxic gas. Autopsy findings included discoloration of lividity and an accentuation of the gray matter of the brain. Toxicology testing confirmed H2S exposure with the demonstration of high levels of thiosulfate in blood.In summary, suicide with H2S appears to be increasing in the United States.

  11. Studies of adsorbate effects on the photoluminescence of cadmium sulfide and cadmium selenide

    SciTech Connect

    Zhang, Zhongju

    1993-12-31

    The electronic properties of semiconductors and their surface and photoluminescence properties are introduced. A short introduction to chemisorption and the Langmuir adsorption isotherm model is presented. The properties of II-VI semiconductors are briefly reviewed. Adsorption from CH{sub 2}Cl{sub 2} solution of a family of ring-substituted, 7,7,8,8-tetracyanoquinodimethane (TCNQ) derivatives onto the surface of etched, single-crystal n-CdSe quenches the band gap photoluminescence (PL) intensity of the semiconductor. PL quenching increases with the electron-withdrawing ability of the ring substituent. The C{sub 60} and C{sub 70} fullerenes can also be adsorbed from toluene solution onto the surfaces of n-CdS, and n-CdSe, causing quenching of the PL intensity. Quantitiatively, the magnitude of the PL quenching can be fit to a dead-layer model, permitting an estimate of maximum expansions in dead-layer thickness caused by adsorption of TCNQ derivatives and C{sub 60} onto the n-CdSe surface to reach {approximately}140 {angstrom} and 130 {angstrom}, respectively. The PL intensity changes are concentration-dependent and give good fits to the Langmuir adsorption isotherm model, yielding equilibrium binding constants on the order of {approximately}10{sup 5} to 10{sup 6} M{sup {minus}1} for TCNQ derivatives and fullerenes, among the largest reported to date.

  12. Luminescent Properties of Graded Cadmium Sulfoselenide Electrodes Prepared from Cadmium Sulfide Substrates.

    DTIC Science & Technology

    1984-09-28

    Sources Division 111 Chapel Street Crane, Indiana 47522 Newton, Massachusetts 02158 S. Ruby Dr. Aaron Wold-// DOE (STOR) Department of Chemistry M.S. 6B025...Physics Department of Physics University of Puerto Rico Washington State University Rio Piedras , Puerto Rico 00931 Pullman, Washington 99164 Dr. Joseph

  13. Cadmium Transporters in the Kidney and Cadmium-Induced Nephrotoxicity

    PubMed Central

    Yang, Hong; Shu, Yan

    2015-01-01

    Among the organs in which the environmental pollutant cadmium causes toxicity, the kidney has gained the most attention in recent years. Numerous studies have sought to unravel the exact pathways by which cadmium enters the renal epithelial cells and the mechanisms by which it causes toxicity in the kidney. The purpose of this review is to present the progress made on the mechanisms of cadmium transport in the kidney and the role of transporter proteins in cadmium-induced nephrotoxicity. PMID:25584611

  14. Cadmium migration in aerospace nickel cadmium cells

    NASA Technical Reports Server (NTRS)

    Mcdermott, P. P.

    1976-01-01

    The effects of temperature, the nature of separator material, charge and discharge, carbonate contamination, and the mode of storage are studied with respect to the migration of active material from the negative toward the positive plate. A theoretical model is proposed which takes into account the solubility of cadmium in various concentrations of hydroxide and carbonate at different temperatures, the generation of the cadmiate ion, Cd(OH)3(-), during discharge, the migration of the cadmiate ion and particulate Cd(OH)2 due to electrophoretic effects and the movement of electrolyte in and out of the negative plate and, finally, the recrystallization of cadmiate ion in the separator as Cd(OH)2. Application of the theoretical model to observations of cadmium migration in cycled cells is also discussed.

  15. Mechanical Activation-Assisted Reductive Leaching of Cadmium from Zinc Neutral Leaching Residue Using Sulfur Dioxide

    NASA Astrophysics Data System (ADS)

    Zhang, Chun; Min, Xiaobo; Chai, Liyuan; Zhang, Jianqiang; Wang, Mi

    2015-12-01

    In this work, zinc neutral leaching residue was mechanically activated by ball-milling. The subsequent leaching behavior and kinetics of cadmium extraction in a mixed SO2-H2SO4 system were studied. Changes in the crystalline phase, lattice distortion, particle size and morphology, which were induced by mechanical activation, were also investigated. The activated samples showed different physicochemical characteristics, and cadmium extraction was found to be easier than for the un-activated samples. Under the same conditions, mechanical activation contributed to higher cadmium leaching. The cadmium extraction kinetics at 75-95°C was found to fit the shrinking core model. The raw neutral leaching residue, and the samples activated for 60 min and 120 min had a calculated activation energy of 65.02 kJ/mol, 59.45 kJ/mol and 53.46 kJ/mol, respectively. The leaching residue was characterized by ICP, XRD and SEM analysis. According to XRD analysis, the main phases in the residue were lead sulfate (PbSO4), zinc sulfide (ZnS) and cadmium sulfide (CdS).

  16. Fatal cadmium-induced pneumonitis.

    PubMed

    Seidal, K; Jörgensen, N; Elinder, C G; Sjögren, B; Vahter, M

    1993-12-01

    A previously relatively healthy 78-year-old man was exposed to cadmium fumes during brazing with cadmium-containing silver solder. He developed severe chemical pneumonitis and died 25 d after exposure.

  17. Aquatic Life Criteria - Cadmium Documents

    EPA Pesticide Factsheets

    Documents pertaining to 2016 Acute and Chronic Aquatic Life Ambient Water Quality Criteria for Cadmium (Freshwater, Estuarine/marine). These documents contain the safe levels of Cadmium in water that should protect the majority of species.

  18. High-efficiency cadmium and zinc-telluride-based thin-film solar cells. Annual subcontract report, 1 March 1990--28 February 1991

    SciTech Connect

    Rohatgi, A.; Sudharsanan, R.; Ringel, S.

    1992-02-01

    This report describes research into polycrystalline CdTe solar cells grown by metal-organic chemical vapor deposition. Efficiencies of {approximately}10% were achieved using both p-i-n and p-n structures. A pre-heat treatment of CdS/SnO{sub 2}/glass substrates at 450{degrees}C in hydrogen atmosphere prior to the CdTe growth was found to be essential for high performance because this heat treatment reduces oxygen-related defects from the CdS surface. However, this treatment also resulted in a Cd-deficient CdS surface, which may in part limit the CdTe cell efficiency to 10% due to Cd vacancy-related interface defects. Preliminary model calculations suggest that removing these states can increase the cell efficiency from 10% to 13.5%. Photon absorption in the CdS film also limits the cell performance, and eliminating this loss mechanism can result in CdTe efficiencies in excess of 18%. Polycrystalline, 1.7-e, CdZnTe films were also grown for tandem-cell applications. CdZnTe/CdS cells processed using the standard CdTe cell fabrication procedure resulted in 4.4% efficiency, high series resistance, and a band-gap shift to 1.55 eV. The formation of Zn-O at and near the CdZnTe surface is the source of high contact resistance. A saturated dichromate each prior to contact deposition was found to solve the contact resistance problem. The CdCl{sub 2} treatment was identified as the cause of the observed band-gap shift due to the preferred formation of ZnCl{sub 2}. 59 refs.

  19. Polycrystalline thin-film cadmium telluride solar cells fabricated by electrodeposition. Annual subcontract report, 20 March 1992--19 March 1993

    SciTech Connect

    Trefny, J.U.; Furtak, T.E.; Wada, N.; Williamson, D.L.; Kim, D.

    1993-08-01

    This report describes progress during the first year of a 3-year program at Colorado School of Mines, based upon earlier studies performed by Ametek Corporation, to develop specific layers of the Ametek n-i-p structure as well as additional studies of several transparent conducting oxides. Thin films of ZnO and ZnO:Al were deposited under various conditions. For the n-layer of the Ametek structure, a dip-coating method was developed for the deposition of CdS films. The authors also present data on the characterization of these films by X-ray diffraction, Raman spectroscopy, scanning tunneling microscopy, small-angle X-ray scattering, and other techniques. They made progress in the electrodeposition of the CdTe i-layer of the Ametek structure. They developed appropriate electrochemical baths and are beginning to understand the role of the many experimental parameters that must be controlled to obtain high-quality films of this material. They explored the possibility of using an electrochemical process for fabricating the ZnTe p-layer. Some preliminary success was achieved, and this step will be pursued in the next phase. Finally, they fabricated a number of ``dot`` solar cells with the structure glass/SnO{sub 2}/CdS/CdTe/Au. Several cells with efficiencies in the range of 5%-6% were obtained, and they are confident, given recent progress, that cells with efficiencies in excess of 10% will be achieved in the near future.

  20. Effect of bioturbation on metal-sulfide oxidation in surficial freshwater sediments

    SciTech Connect

    Peterson, G.S.; Ankley, G.T.; Leonard, E.N.

    1996-12-01

    Recent studies have demonstrated the role of acid-volatile sulfide (AVS) in controlling the bioavailability of several cationic metals in anoxic sediments. However, metal-sulfide complexes can be relatively labile with respect to oxidation associated with factors such as seasonal changes in rates of oxidation/production of AVS. Another potentially important mechanism of AVS oxidation in surficial sediments is bioturbation. The authors used different densities of the burrowing oligochaete Lumbriculus variegatus in a series of laboratory experiments to evaluate the effect of bioturbation on oxidation of AVS and subsequent bioavailability of cadmium and zinc spiked into freshwater sediments. Metal bioavailability was determined directly by bioaccumulation in the test organisms and indirectly through analysis of interstitial (pore) water metal concentrations. In the studies, horizon-specific sediment analyses were conducted to assess spatial differences in AVS and pore-water metal concentrations specifically related to organism activity. Burrowing activity of the oligochaete significantly reduced AVS concentrations in surficial sediments in a density-dependent manner and resulted in elevated interstitial water concentrations of cadmium but not zinc. Concentrations of cadmium in pore water from deeper horizons were consistently lower than those in the surficial sediments. The bioaccumulation of cadmium, but not zinc, but the oligochaetes. Overall, the results indicate that bioturbation can enhance the bioavailability of some cationic metals in surficial sediments, via oxidation of AVS, and demonstrate the importance of analyzing surficial sediments when assessing bioavailability of metals in sediments.

  1. High transmittance cadmium oxysulfide Cd(S,O) buffer layer grown by triton X-100 mediated chemical bath deposition for thin-film heterojunction solar cells

    NASA Astrophysics Data System (ADS)

    Ballipinar, Faruk; Rastogi, A. C.

    2017-01-01

    Polycrystalline 100-190 nm Cd(S,O) n-type semiconductor thin films of high transparency in the visible range are deposited by a surfactant Triton X-100 mediated chemical bath deposition process. The crystalline structure of the films revealed by X-ray diffraction data shows a cubic-CdO phase signified by (111) and (200) planes alongside the (002), (220), and (110) planes from hexagonal-CdS. The invariance of the 2θ position of the (002) CdS diffraction is interpreted in terms of the growth of the composite film essentially by the formation of a dilute interstitial alloy of CdO and CdS. This is confirmed by Raman spectra which, besides the CdS 1LO and 2LO modes at 300 and 600 cm-1, also show Raman lines from CdO at 1098 cm-1 and 952 cm-1 assigned as overtone of 2LO phonon modes and 556 cm-1 due to band crossing between LO and TO modes of CdO. Optical spectra of Cd(S,O) films show a median transmittance of >85% compared to ˜70% for CdS films in the 550-1000 nm wavelength range. The Cd(S,O) films show optical bandgap varying from 2.34 to 2.26 eV with increasing CdO fraction but retain high sub-bandgap transmission and sharp band edge threshold. The Cd(S,O) films thus offer an alternative to the CdS buffer layer in the heterojunction solar cells, which has major shortcoming of poor stability and high sub-bandgap absorption. The photoluminescence spectra of Cd(S,O) films show three green bands, of which one is the near band edge transition at 511.5 nm, the same as in CdS, the second band at 526.0 nm that red shifted from the CdS position is due to shallow donor-acceptor defects arising from structural change due to CdO, and the third band at 543.6 nm (2.28 eV) originates from direct band transition in CdO. The growth mechanism of Cd(S,O) films is described, which invokes that the Triton X-100 molecule modifies the microenvironment around adsorbed [Cd(NH3)4]2+ species, thereby inducing two concurrent reactions, one with SH- species that cause CdS formation and the

  2. Sulfide bonded atomic radii

    NASA Astrophysics Data System (ADS)

    Gibbs, G. V.; Ross, N. L.; Cox, D. F.

    2017-03-01

    The bonded radius, r b(S), of the S atom, calculated for first- and second-row non-transition metal sulfide crystals and third-row transition metal sulfide molecules and crystals indicates that the radius of the sulfur atom is not fixed as traditionally assumed, but that it decreases systematically along the bond paths of the bonded atoms with decreasing bond length as observed in an earlier study of the bonded radius of the oxygen atom. When bonded to non-transition metal atoms, r b(S) decreases systematically with decreasing bond length from 1.68 Å when the S atom is bonded to the electropositive VINa atom to 1.25 Å when bonded to the more electronegative IVP atom. In the case of transition metal atoms, rb(S) likewise decreases with decreasing bond length from 1.82 Å when bonded to Cu and to 1.12 Å when bonded to Fe. As r b(S) is not fixed at a given value but varies substantially depending on the bond length and the field strength of the bonded atoms, it is apparent that sets of crystal and atomic sulfide atomic radii based on an assumed fixed radius for the sulfur atom are satisfactory in that they reproduce bond lengths, on the one hand, whereas on the other, they are unsatisfactory in that they fail to define the actual sizes of the bonded atoms determined in terms of the minima in the electron density between the atoms. As such, we urge that the crystal chemistry and the properties of sulfides be studied in terms of the bond lengths determined by adding the radii of either the atomic and crystal radii of the atoms but not in terms of existing sets of crystal and atomic radii. After all, the bond lengths were used to determine the radii that were experimentally determined, whereas the individual radii were determined on the basis of an assumed radius for the sulfur atom.

  3. Sulfide bonded atomic radii

    NASA Astrophysics Data System (ADS)

    Gibbs, G. V.; Ross, N. L.; Cox, D. F.

    2017-09-01

    The bonded radius, r b(S), of the S atom, calculated for first- and second-row non-transition metal sulfide crystals and third-row transition metal sulfide molecules and crystals indicates that the radius of the sulfur atom is not fixed as traditionally assumed, but that it decreases systematically along the bond paths of the bonded atoms with decreasing bond length as observed in an earlier study of the bonded radius of the oxygen atom. When bonded to non-transition metal atoms, r b(S) decreases systematically with decreasing bond length from 1.68 Å when the S atom is bonded to the electropositive VINa atom to 1.25 Å when bonded to the more electronegative IVP atom. In the case of transition metal atoms, rb(S) likewise decreases with decreasing bond length from 1.82 Å when bonded to Cu and to 1.12 Å when bonded to Fe. As r b(S) is not fixed at a given value but varies substantially depending on the bond length and the field strength of the bonded atoms, it is apparent that sets of crystal and atomic sulfide atomic radii based on an assumed fixed radius for the sulfur atom are satisfactory in that they reproduce bond lengths, on the one hand, whereas on the other, they are unsatisfactory in that they fail to define the actual sizes of the bonded atoms determined in terms of the minima in the electron density between the atoms. As such, we urge that the crystal chemistry and the properties of sulfides be studied in terms of the bond lengths determined by adding the radii of either the atomic and crystal radii of the atoms but not in terms of existing sets of crystal and atomic radii. After all, the bond lengths were used to determine the radii that were experimentally determined, whereas the individual radii were determined on the basis of an assumed radius for the sulfur atom.

  4. Field method for sulfide determination

    SciTech Connect

    Wilson, B L; Schwarser, R R; Chukwuenye, C O

    1982-01-01

    A simple and rapid method was developed for determining the total sulfide concentration in water in the field. Direct measurements were made using a silver/sulfide ion selective electrode in conjunction with a double junction reference electrode connected to an Orion Model 407A/F Specific Ion Meter. The method also made use of a sulfide anti-oxidant buffer (SAOB II) which consists of ascorbic acid, sodium hydroxide, and disodium EDTA. Preweighed sodium sulfide crystals were sealed in air tight plastic volumetric flasks which were used in standardization process in the field. Field standards were prepared by adding SAOB II to the flask containing the sulfide crystals and diluting it to the mark with deionized deaerated water. Serial dilutions of the standards were used to prepare standards of lower concentrations. Concentrations as low as 6 ppB were obtained on lake samples with a reproducibility better than +- 10%.

  5. Cadmium in the aquatic environment

    SciTech Connect

    Nriagu, J.O.; Sprague, J.B.

    1987-01-01

    This volume presents a comprehensive account of current research on the chemistry and toxicology of cadmium in natural waters. The first four chapters focus on the sources (natural vs. anthropogenic), behavior, and fate of cadmium in natural waters. These are followed by three chapters on the biocycling and effects of cadmium on freshwater biota. The ecotoxicity of cadmium to marine biota are covered by the next two chapters. The final chapter presents a succinct review of the analytical chemistry of cadmium in natural waters.

  6. Fabrication and investigation of the optoelectrical properties of MoS2/CdS heterojunction solar cells.

    PubMed

    Gu, Weixia; Yang, Fan; Wu, Chen; Zhang, Yi; Shi, Miaoyuan; Ma, Xiying

    2014-01-01

    Molybdenum disulfide (MoS2)/cadmium sulfide (CdS) heterojunction solar cells were successfully synthesized via chemical bath deposition (CBD) and chemical vapor deposition (CVD). The as-grown CdS film on a fluorine tin oxide (FTO) substrate deposited by CBD is continuous and compact. The MoS2 film deposited by CVD is homogeneous and continuous, with a uniform color and a thickness of approximately 10 nm. The optical absorption range of the MoS2/CdS heterojunction covers the visible and near-infrared spectral regions of 350 to 800 nm, which is beneficial for the improvement of solar cell efficiency. Moreover, the MoS2/CdS solar cell exhibits good current-voltage (I-V) characteristics and pronounced photovoltaic behavior, with an open-circuit voltage of 0.66 V and a short-circuit current density of 0.227 × 10(-6) A/cm(2), comparable to the results obtained from other MoS2-based solar cells. This research is critical to investigate more efficient and stable solar cells based on graphene-like materials in the future.

  7. Fabrication and investigation of the optoelectrical properties of MoS2/CdS heterojunction solar cells

    PubMed Central

    2014-01-01

    Molybdenum disulfide (MoS2)/cadmium sulfide (CdS) heterojunction solar cells were successfully synthesized via chemical bath deposition (CBD) and chemical vapor deposition (CVD). The as-grown CdS film on a fluorine tin oxide (FTO) substrate deposited by CBD is continuous and compact. The MoS2 film deposited by CVD is homogeneous and continuous, with a uniform color and a thickness of approximately 10 nm. The optical absorption range of the MoS2/CdS heterojunction covers the visible and near-infrared spectral regions of 350 to 800 nm, which is beneficial for the improvement of solar cell efficiency. Moreover, the MoS2/CdS solar cell exhibits good current-voltage (I-V) characteristics and pronounced photovoltaic behavior, with an open-circuit voltage of 0.66 V and a short-circuit current density of 0.227 × 10-6 A/cm2, comparable to the results obtained from other MoS2-based solar cells. This research is critical to investigate more efficient and stable solar cells based on graphene-like materials in the future. PMID:25593552

  8. Fabrication and investigation of the optoelectrical properties of MoS2/CdS heterojunction solar cells

    NASA Astrophysics Data System (ADS)

    Gu, Weixia; Yang, Fan; Wu, Chen; Zhang, Yi; Shi, Miaoyuan; Ma, Xiying

    2014-12-01

    Molybdenum disulfide (MoS2)/cadmium sulfide (CdS) heterojunction solar cells were successfully synthesized via chemical bath deposition (CBD) and chemical vapor deposition (CVD). The as-grown CdS film on a fluorine tin oxide (FTO) substrate deposited by CBD is continuous and compact. The MoS2 film deposited by CVD is homogeneous and continuous, with a uniform color and a thickness of approximately 10 nm. The optical absorption range of the MoS2/CdS heterojunction covers the visible and near-infrared spectral regions of 350 to 800 nm, which is beneficial for the improvement of solar cell efficiency. Moreover, the MoS2/CdS solar cell exhibits good current-voltage ( I- V) characteristics and pronounced photovoltaic behavior, with an open-circuit voltage of 0.66 V and a short-circuit current density of 0.227 × 10-6 A/cm2, comparable to the results obtained from other MoS2-based solar cells. This research is critical to investigate more efficient and stable solar cells based on graphene-like materials in the future.

  9. A statistical approach for optimizing parameters for electrodeposition of indium (III) sulfide (In2S3) films, potential low-hazard buffer layers for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Mughal, Maqsood Ali

    Clean and environmentally friendly technologies are centralizing industry focus towards obtaining long term solutions to many large-scale problems such as energy demand, pollution, and environmental safety. Thin film solar cell (TFSC) technology has emerged as an impressive photovoltaic (PV) technology to create clean energy from fast production lines with capabilities to reduce material usage and energy required to manufacture large area panels, hence, lowering the costs. Today, cost ($/kWh) and toxicity are the primary challenges for all PV technologies. In that respect, electrodeposited indium sulfide (In2S3) films are proposed as an alternate to hazardous cadmium sulfide (CdS) films, commonly used as buffer layers in solar cells. This dissertation focuses upon the optimization of electrodeposition parameters to synthesize In2S3 films of PV quality. The work describe herein has the potential to reduce the hazardous impact of cadmium (Cd) upon the environment, while reducing the manufacturing cost of TFSCs through efficient utilization of materials. Optimization was performed through use of a statistical approach to study the effect of varying electrodeposition parameters upon the properties of the films. A robust design method referred-to as the "Taguchi Method" helped in engineering the properties of the films, and improved the PV characteristics including optical bandgap, absorption coefficient, stoichiometry, morphology, crystalline structure, thickness, etc. Current density (also a function of deposition voltage) had the most significant impact upon the stoichiometry and morphology of In2S3 films, whereas, deposition temperature and composition of the solution had the least significant impact. The dissertation discusses the film growth mechanism and provides understanding of the regions of low quality (for example, cracks) in films. In2S3 films were systematically and quantitatively investigated by varying electrodeposition parameters including bath

  10. Commercialization of a thick-film solar cell. Final technical report, September 15, 1980-April 30, 1981

    SciTech Connect

    McDonald, G. D.

    1981-01-01

    No technical problems were encountered in the preparation of screen printed cadmium sulfide layers. High conductivity (less than 5 ohm cm resistivities) adherent layers could be produced on 7059 glass, Nesatron and tin oxide coated glass. No macro pinholes were observed in thick films. Solar cells produced from screen printed CdS had a maximum open circuit voltage of 0.44 volt and a maximum observed short circuit current of 8 ma/cm/sup 2/ under AM 1 illumination. A maximum cell efficiency of 2.2% was obtained. This performance is not felt to be a limitation produced by the screen printing approach but to be reflective of an unoptimized procedure for producing Cu/sub 2/S on the CdS film and the lack of a suitable post thermal treatment technique.

  11. Solution processable RGO-CdZnS composite for solar light responsive photocatalytic degradation of 4-Nitrophenol

    NASA Astrophysics Data System (ADS)

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

    2017-05-01

    We report the one pot single step synthesis and characterization of solution processable reduced graphene oxide (RGO) - cadmium zinc sulfide (CdZnS) nanocomposite materials. The composite was characterized structurally and morphologically by XRD and TEM studies. The reduction of GO in RGO-CdZnS composite, was confirmed by XPS and Raman spectroscopy. The photocatalytic activity of the RGO-CdZnS composite was investigated towards the degradation of 4-Nitrophenol. A notable increase of photocatalytic efficiency of RGO-CdZnS compare to controlled CdZnS was observed. Here RGO plays a crucial role to efficient photo induced charge separation from the CdZnS, and decreases the electron-hole recombination probability and subsequently enhanced the photocatalytic activity of the RGO-CdZnS composite material under simulated solar light irradiation. This work highlights the potential application of RGO-based materials in the field of photocatalytic degradation of organic water pollutant.

  12. Sulfide Mineral Surfaces

    SciTech Connect

    Rosso, Kevin M.; Vaughan, David J.

    2006-08-01

    The past twenty years or so have seen dramatic development of the experimental and theoretical tools available to study the surfaces of solids at the molecular (?atomic resolution?) scale. On the experimental side, two areas of development well illustrate these advances. The first concerns the high intensity photon sources associated with synchrotron radiation; these have both greatly improved the surface sensitivity and spatial resolution of already established surface spectroscopic and diffraction methods, and enabled the development of new methods for studying surfaces. The second centers on the scanning probe microscopy (SPM) techniques initially developed in the 1980's with the first scanning tunneling microscope (STM) and atomic force microscope (AFM) experiments. The direct 'observation' of individual atoms at surfaces made possible with these methods has truly revolutionized surface science. On the theoretical side, the availability of high performance computers coupled with advances in computational modeling has provided powerful new tools to complement the advances in experiment. Particularly important have been the quantum mechanics based computational approaches such as density functional theory (DFT), which can now be easily used to calculate the equilibrium crystal structures of solids and surfaces from first principles, and to provide insights into their electronic structure. In this chapter, we review current knowledge of sulfide mineral surfaces, beginning with an overview of the principles relevant to the study of the surfaces of all crystalline solids. This includes the thermodynamics of surfaces, the atomic structure of surfaces (surface crystallography and structural stability, adjustments of atoms at the surface through relaxation or reconstruction, surface defects) and the electronic structure of surfaces. We then discuss examples where specific crystal surfaces have been studied, with the main sulfide minerals organized by structure type

  13. Electrostatic Field Influence on Luminescence Features of Cadmium Sulphide Quantum Dots in Silica Matrix

    NASA Astrophysics Data System (ADS)

    Voznesenskiy, S. S.; Sergeev, A. A.; Postnova, I. V.; Shchipunov, Y. A.

    The effect of electrostatic field on optical properties of silicate nanocomposite with cadmium sulfide quantum dots was investigated. It was found that the electrostatic field causes quantum dot orientation along the field force lines leading to changes in the polarized components of the luminescence spectrum. The influence of field force line direction on photoinduced absorption characteristics arised from λ = 405.9 nm laser radiation exposure to nanocomposite was shown.

  14. Fabrication and applications of copper sulfide (CuS) nanostructures

    NASA Astrophysics Data System (ADS)

    Shamraiz, Umair; Hussain, Raja Azadar; Badshah, Amin

    2016-06-01

    This review article presents different fabrication procedures (under the headlines of solvothermal routes, aerosol methods, solution methods and thermolysis), and applications (photocatalytic degradation, ablation of cancer cells, electrode material in lithium ion batteries and in gas sensing, organic solar cells, field emission properties, super capacitor applications, photoelectrochemical performance of QDSCs, photocatalytic reduction of organic pollutants, electrochemical bio sensing, enhanced PEC characteristics of pre-annealed CuS film electrodes) of copper sulfide (Covellite).

  15. Cadmium plating replacements

    NASA Technical Reports Server (NTRS)

    Nelson, Mary J.; Groshart, Earl C.

    1995-01-01

    The Boeing Company has been searching for replacements to cadmium plate. Two alloy plating systems seem close to meeting the needs of a cadmium replacement. The two alloys, zinc-nickel and tin-zinc are from alloy plating baths; both baths are neutral pH. The alloys meet the requirements for salt fog corrosion resistance, and both alloys excel as a paint base. Currently, tests are being performed on standard fasteners to compare zinc-nickel and tin-zinc on threaded hardware where cadmium is heavily used. The Hydrogen embrittlement propensity of the zinc-nickel bath has been tested, and just beginning for the tin-zinc bath. Another area of interest is the electrical properties on aluminum for tin-zinc and will be discussed. The zinc-nickel alloy plating bath is in production in Boeing Commercial Airplane Group for non-critical low strength steels. The outlook is promising that these two coatings will help The Boeing Company significantly reduce its dependence on cadmium plating.

  16. Cadmium plating replacements

    SciTech Connect

    Nelson, M.J.; Groshart, E.C.

    1995-03-01

    The Boeing Company has been searching for replacements to cadmium plate. Two alloy plating systems seem close to meeting the needs of a cadmium replacement. The two alloys, zinc-nickel and tin-zinc are from alloy plating baths; both baths are neutral pH. The alloys meet the requirements for salt fog corrosion resistance, and both alloys excel as a paint base. Currently, tests are being performed on standard fasteners to compare zinc-nickel and tin-zinc on threaded hardware where cadmium is heavily used. The Hydrogen embrittlement propensity of the zinc-nickel bath has been tested, and just beginning for the tin-zinc bath. Another area of interest is the electrical properties on aluminum for tin-zinc and will be discussed. The zinc-nickel alloy plating bath is in production in Boeing Commercial Airplane Group for non-critical low strength steels. The outlook is promising that these two coatings will help The Boeing Company significantly reduce its dependence on cadmium plating.

  17. CADMIUM PHOSPHATE GLASS

    DOEpatents

    Carpenter, H.W.; Johnson, P.D.

    1963-04-01

    A method of preparing a cadmium phosphate glass that comprises providing a mixture of solid inorganic compounds of cadmuim and phosphate having vaporizable components and heating the resulting composition to a temperature of at least 850 un. Concent 85% C is presented. (AEC)

  18. Volcanogenic Massive Sulfide Deposit Density

    USGS Publications Warehouse

    Mosier, Dan L.; Singer, Donald A.; Berger, Vladimir I.

    2007-01-01

    A mineral-deposit density model for volcanogenic massive sulfide deposits was constructed from 38 well-explored control areas from around the world. Control areas contain at least one exposed volcanogenic massive sulfide deposit. The control areas used in this study contain 150 kuroko, 14 Urals, and 25 Cyprus massive sulfide subtypes of volcanogenic massive sulfide deposits. For each control area, extent of permissive rock, number of exposed volcanogenic massive sulfide deposits, map scale, deposit age, and deposit density were determined. The frequency distribution of deposit densities in these 38 control areas provides probabilistic estimates of the number of deposits for tracts that are permissive for volcanogenic massive sulfide deposits-90 percent of the control areas have densities of 100 or more deposits per 100,000 square kilometers, 50 percent of the control areas have densities of 700 or more deposits per 100,000 square kilometers, and 10 percent of the control areas have densities of 3,700 or more deposits per 100,000 square kilometers. Both map scale and the size of the control area are shown to be predictors of deposit density. Probabilistic estimates of the number of volcanogenic massive sulfide deposits can be made by conditioning the estimates on sizes of permissive area. The model constructed for this study provides a powerful tool for estimating the number of undiscovered volcanogenic massive sulfide deposits when conducting resource assessments. The value of these deposit densities is due to the consistency of these models with the grade and tonnage and the descriptive models. Mineral-deposit density models combined with grade and tonnage models allow reasonable estimates of the number, size, and grades of volcanogenic massive sulfide deposits to be made.

  19. Sulfides and oxides in comets

    NASA Technical Reports Server (NTRS)

    Rietmeijer, Frans J. M.

    1988-01-01

    Metal abundances associated with Sun-grazing P/comet Ikeya-Seki 1965f, the mineralogy of chrondritic interplanetary dust particles and cosmochemical affinities of Co, V, Cr, and Ni in extraterrestrial materials and probable vaporization data for nonsilicate minerals are used to evaluate the putative dearth of nonsilicates in short-period comets. It is concluded that sulfides and oxides are common, albeit minor, constituents of these comets. Sulfides and oxides can form in situ during perihelion passage in the nucleus of active short-period comets by sulfidation of Mg, Fe-silicates.

  20. Sulfides and oxides in comets

    NASA Technical Reports Server (NTRS)

    Rietmeijer, Frans J. M.

    1988-01-01

    Metal abundances associated with Sun-grazing P/comet Ikeya-Seki 1965f, the mineralogy of chrondritic interplanetary dust particles and cosmochemical affinities of Co, V, Cr, and Ni in extraterrestrial materials and probable vaporization data for nonsilicate minerals are used to evaluate the putative dearth of nonsilicates in short-period comets. It is concluded that sulfides and oxides are common, albeit minor, constituents of these comets. Sulfides and oxides can form in situ during perihelion passage in the nucleus of active short-period comets by sulfidation of Mg, Fe-silicates.

  1. Assessment of cadmium in aquatic sediment using dialysis samplers with ion-exchange-resin collection

    SciTech Connect

    Shi, B.; Allen, H.E.; Desnoyers, C.

    1998-05-01

    Simultaneously extracted metals (SEM) and acid volatile sulfide (AVS) show the potential for toxicity on the basis of their ratio. Accordingly, the authors spiked cadmium in a range for which Cd/AVS ratios were from 0.2 to 10 in the sediment with its weight about 8 kg in each batch. Dialysis samplers with a cation ion-exchange resin (Dowex 50W-X4) collection were used in a laboratory for the determination of free cadmium concentrations in pore water of the collected sediment. When equilibrium was reached among cadmium in pore water, sediment, and ion-exchange resin, cadmium exchanged onto resin phase was regenerated with 1 N hydrochloric acid (OPTIMA grade) and determined using an atomic absorption spectrophotometer (Zeeman 5000) with a graphite furnace accessory. Cadmium determined using the dialysis sampler is considered as free cadmium which is related to the metal bioavailability toward aquatic biota. The developed methodology provides a new technique for assessment of free metal in aquatic sediment systems.

  2. Apparatus for use in sulfide chemiluminescence detection

    DOEpatents

    Spurlin, S.R.; Yeung, E.S.

    1987-01-06

    A method is described for chemiluminescently determining a sulfide which is either hydrogen sulfide or methyl mercaptan by reacting the sulfide with chlorine dioxide at low pressure and under conditions which allow a longer reaction time in emission of a single photon for every two sulfide containing species, and thereafter, chemiluminescently detecting and determining the sulfide. The invention also relates not only to the detection method, but the novel chemical reaction and a specifically designed chemiluminescence detection cell for the reaction. 4 figs.

  3. Apparatus for use in sulfide chemiluminescence detection

    DOEpatents

    Spurlin, Stanford R.; Yeung, Edward S.

    1987-01-01

    A method of chemiluminescently determining a sulfide which is either hydrogen sulfide or methyl mercaptan by reacting the sulfide with chlorine dioxide at low pressure and under conditions which allow a longer reaction time in emission of a single photon for every two sulfide containing species, and thereafter, chemiluminescently detecting and determining the sulfide. The invention also relates not only to the detection method, but the novel chemical reaction and a specifically designed chemiluminescence detection cell for the reaction.

  4. Prevention of sulfide oxidation in sulfide-rich waste rock

    NASA Astrophysics Data System (ADS)

    Nyström, Elsa; Alakangas, Lena

    2015-04-01

    The ability to reduce sulfide oxidation in waste rock after mine closure is a widely researched area, but to reduce and/or inhibit the oxidation during operation is less common. Sulfide-rich (ca 30 % sulfur) waste rock, partially oxidized, was leached during unsaturated laboratory condition. Trace elements such as As and Sb were relatively high in the waste rock while other sulfide-associated elements such as Cu, Pb and Zn were low compared to common sulfide-rich waste rock. Leaching of unsaturated waste rock lowered the pH, from around six down to two, resulting in continuously increasing element concentrations during the leaching period of 272 days. The concentrations of As (65 mg/L), Cu (6.9 mg/L), Sb (1.2 mg/L), Zn (149 mg/L) and S (43 g/L) were strongly elevated at the end of the leaching period. Different alkaline industrial residues such as slag, lime kiln dust and cement kiln dust were added as solid or as liquid to the waste rock in an attempt to inhibit sulfide oxidation through neo-formed phases on sulfide surfaces in order to decrease the mobility of metals and metalloids over longer time scale. This will result in a lower cost and efforts of measures after mine closure. Results from the experiments will be presented.

  5. Chemically Deposited Thin-Film Solar Cell Materials

    NASA Technical Reports Server (NTRS)

    Raffaelle, R.; Junek, W.; Gorse, J.; Thompson, T.; Harris, J.; Hehemann, D.; Hepp, A.; Rybicki, G.

    2005-01-01

    We have been working on the development of thin film photovoltaic solar cell materials that can be produced entirely by wet chemical methods on low-cost flexible substrates. P-type copper indium diselenide (CIS) absorber layers have been deposited via electrochemical deposition. Similar techniques have also allowed us to incorporate both Ga and S into the CIS structure, in order to increase its optical bandgap. The ability to deposit similar absorber layers with a variety of bandgaps is essential to our efforts to develop a multi-junction thin-film solar cell. Chemical bath deposition methods were used to deposit a cadmium sulfide (CdS) buffer layers on our CIS-based absorber layers. Window contacts were made to these CdS/CIS junctions by the electrodeposition of zinc oxide (ZnO). Structural and elemental determinations of the individual ZnO, CdS and CIS-based films via transmission spectroscopy, x-ray diffraction, x-ray photoelectron spectroscopy and energy dispersive spectroscopy will be presented. The electrical characterization of the resulting devices will be discussed.

  6. Hydrogen from solar energy

    SciTech Connect

    Nix, R.G.

    1984-07-01

    This paper describes those portions of the Photo/Thermochemical Research Program that possibly apply to the production of hydrogen from sources such as water or hydrogen sulfide. That research centers around understanding high flux solids decomposition reactions and how to best exploit photoreactions so the energy contained in the entire solar spectrum is used. 2 references, 4 figures.

  7. Platinum metals magmatic sulfide ores.

    PubMed

    Naldrett, A J; Duke, J M

    1980-06-27

    Platinum-group elements (PGE) are mined predominantly from deposits that have formed by the segregation of molten iron-nickel-copper sulfides from silicate magmas. The absolute concentrations of PGE in sulfides from different deposits vary over a range of five orders of magnitude, whereas those of other chalcophile elements vary by factors of only 2 to 100. However, the relative proportions of the different PGE in a given deposit are systematically related to the nature of the parent magma. The absolute and relative concentrations of PGE in magmatic sulfides are explained in terms of the degree of partial melting of mantle peridotite required to produce the parent magma and the processes of batch equilibration and fractional segregation of sulfides. The Republic of South Africa and the U.S.S.R. together possess more than 97 percent of the world PGE reserves, but significant undeveloped resources occur in North America. The Stillwater complex in Montana is perhaps the most important example.

  8. Hydrogen sulfide in signaling pathways.

    PubMed

    Olas, Beata

    2015-01-15

    For a long time hydrogen sulfide (H₂S) was considered a toxic compound, but recently H₂S (at low concentrations) has been found to play an important function in physiological processes. Hydrogen sulfide, like other well-known compounds - nitric oxide (NO) and carbon monoxide (CO) is a gaseous intracellular signal transducer. It regulates the cell cycle, apoptosis and the oxidative stress. Moreover, its functions include neuromodulation, regulation of cardiovascular system and inflammation. In this review, I focus on the metabolism of hydrogen sulfide (including enzymatic pathways of H₂S synthesis from l- and d-cysteine) and its signaling pathways in the cardiovascular system and the nervous system. I also describe how hydrogen sulfide may be used as therapeutic agent, i.e. in the cardiovascular diseases.

  9. Thermoelectric Properties of Lanthanum Sulfide

    NASA Technical Reports Server (NTRS)

    Wood, C.; Lockwood, R.; Parker, J. B.; Zoltan, A.; Zoltan, L. D.; Danielson, L.; Raag, V.

    1987-01-01

    Report describes measurement of Seebeck coefficient, electrical resistivity, thermal conductivity, and Hall effect in gamma-phase lanthanum sulfide with composition of La3-x S4. Results of study, part of search for high-temperature thermoelectric energy-conversion materials, indicate this sulfide behaves like extrinsic semiconductor over temperature range of 300 to 1,400 K, with degenerate carrier concentration controlled by stoichiometric ratio of La to S.

  10. Thermoelectric Properties of Lanthanum Sulfide

    NASA Technical Reports Server (NTRS)

    Wood, C.; Lockwood, R.; Parker, J. B.; Zoltan, A.; Zoltan, L. D.; Danielson, L.; Raag, V.

    1987-01-01

    Report describes measurement of Seebeck coefficient, electrical resistivity, thermal conductivity, and Hall effect in gamma-phase lanthanum sulfide with composition of La3-x S4. Results of study, part of search for high-temperature thermoelectric energy-conversion materials, indicate this sulfide behaves like extrinsic semiconductor over temperature range of 300 to 1,400 K, with degenerate carrier concentration controlled by stoichiometric ratio of La to S.

  11. Cadmium hazard in silver brazing.

    PubMed

    Gan, S L; Tan, S H; Pinnagoda, J; Tan, K T

    1995-03-01

    This study evaluates the usage of cadmium-containing silver brazing alloys in Singapore and the potential cadmium hazard from its use. Of the 137 factories which responded to the survey questionnaire, only 28 (20.4%) carried out brazing. Of these, only 7 factories used cadmium-containing filler alloys. One hundred and six out of 123 workers from one of these factories had cadmium-in-blood concentrations exceeding 10 mcg/l. Thirty-one (29.2%) of the workers with excessive cadmium absorption had urinary beta-2 microglobulin levels exceeding 28 mcg/g creat. Workers in the other factories who were intermittently exposed had cadmium-in-blood concentrations of 10 mcg/l and below.

  12. POLYCRYSTALLINE THIN FILM SOLAR CELLS:Present Status and Future Potential

    NASA Astrophysics Data System (ADS)

    Birkmire, Robert W.; Eser, Erten

    1997-08-01

    Polycrystalline thin film solar cells on copper indium diselenide (CulnSe2) and its alloys and cadmium telluride (CdTe) appear to be the most promising candidates for large-scale application of photovoltaic energy conversion because they have shown laboratory-efficiences in excess of 15%. Heterojunction devices with n-type cadmium sulfide (CdS) films show very low minority carrier recombination at the absorber grain boundaries and at the metallurgical interface, which results in high quantum efficiences. Open circuit voltages of these devices are relatively low owing to the recombination in the space charge region in the absorber. Further improvements in efficiency can be achieved by reducing the recombination current, especially in devices based on CulnSe2 and its alloys. Low-cost manufacturing of modules requires better resolution of a number of other technical issues. For modules based on CulnSe2 and its alloys, the role of Na and higher deposition rates on device performance need to be better understood. In addition, replacing the chemical bath deposition method for CdS film deposition with an equally effective, but more environmentally acceptable process is needed. For modules based on CdTe, more fundamental understanding of the effect of chloride/oxygen treatment and the development of more reproducible and manufacturable CdTe contacting schemes are necessary.

  13. Cadmium-tolerant bacteria reduce the uptake of cadmium in rice: potential for microbial bioremediation.

    PubMed

    Siripornadulsil, Surasak; Siripornadulsil, Wilailak

    2013-08-01

    We selected 24 bacterial isolates that could tolerate up to 2500 µM CdCl2 from the soil of rice fields downstream from a zinc-mineralized area contaminated with a high level of cadmium (Cd). In the presence of 500 µM CdCl2, all isolates grew slower and with a prolonged lag-phase compared to in the absence of Cd. Cd-binding capacity was high and ranged from 6.38 to 9.38 log[Cd(atom)]/cell. The stability of Cd complexes in bacteria was affected by 1mM EDTA. In 500 µM CdCl2, all isolates produced 0.7 to 4.8-fold more inorganic sulfide and 0.6 to 2.2-fold more thio-rich compounds containing SH groups. Out of 24 Cd-tolerant bacterial isolates, KKU2500-3, -8, -9 and -20 were able to promote the growth of Thai jasmine rice (Kao Hom Mali 105) seedlings in the presence of 200 µM CdCl2, and KKU2500-3 produced the highest numbers of fibrous root. Interestingly, these 4 isolates increased Cd tolerance and decreased the accumulation of Cd in rice by 61, 9, 6, and 17% when grown in the presence of 200 µM CdCl2. Of the 4 isolates, KKU2500-3 produced more inorganic sulfide when grown in CdCl2 at 500-2000 µM. XANES analyses indicated that this isolate precipitated a detectable amount of cadmium sulfide (CdS) when grown in 500 µM CdCl2. Thus, the isolate KKU2500-3 could possibly transform toxic, soluble CdCl2 into non-toxic, insoluble CdS. These 4Cd-tolerant bacterial isolates were identified via 16S rDNA sequencing and classified as Cupriavidus taiwanensis KKU2500-3 and Pseudomonas aeruginosa KKU2500-8, -9, and -20. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Nickel-cadmium cells

    NASA Technical Reports Server (NTRS)

    Rubin, E. J.; Turchan, M. J.

    1974-01-01

    A high energy density nickel cadmium cell of aerospace quality was designed. The approach used was to utilize manufacturing techniques which produce highly uniform and controlled starting materials in addition to improvements in the overall design. Parameters controlling the production of plaque and both positive and negative plate were studied. Quantities of these materials were produced and prototype cells were assembled to test the proposed design.

  15. Cadmium sulfite hexahydrate revisited

    PubMed Central

    Baggio, Sergio; Ibáñez, Andrés; Baggio, Ricardo

    2008-01-01

    The present structural revision of the title compound, tetra­cadmium tetra­sulfite hexa­hydrate, [Cd4(SO3)4(H2O)5]·H2O, is a low-temperature upgrade (T = 100 K and R = 0.017) of the original room-temperature structure reported by Kiers & Vos [Cryst. Struct. Commun. (1978). 7, 399–403; T = 293 K and R = 0.080). The compound is a three-dimensional polymer with four independent cadmium centres, four sulfite anions and six water mol­ecules, five of them coordinated to two cadmium centres and the remaining one an unbound solvent mol­ecule which completes the asymmetric unit. There are two types of cadmium environment: CdO8 (through four chelating sulfite ligands) and CdO6 (by way of six monocoordinated ligands). The former groups form planar arrays [parallel to (001) and separated by half a unit cell translation along c], made up of chains running along [110] and [10], respectively. These chains are, in turn, inter­connected both in an intra­planar as well as in an inter­planar fashion by the latter CdO6 polyhedra into a tight three-dimensional framework. There is, in addition, an extensive network of hydrogen bonds, in which all 12 water H atoms act as donors and eight O atoms from all four sulfite groups and two water mol­ecules act as acceptors. PMID:21202728

  16. Ecofriendly and Nonvacuum Electrostatic Spray-Assisted Vapor Deposition of Cu(In,Ga)(S,Se)2 Thin Film Solar Cells.

    PubMed

    Hossain, Md Anower; Wang, Mingqing; Choy, Kwang-Leong

    2015-10-14

    Chalcopyrite Cu(In,Ga)(S,Se)2 (CIGSSe) thin films have been deposited by a novel, nonvacuum, and cost-effective electrostatic spray-assisted vapor deposition (ESAVD) method. The generation of a fine aerosol of precursor solution, and their controlled deposition onto a molybdenum substrate, results in adherent, dense, and uniform Cu(In,Ga)S2 (CIGS) films. This is an essential tool to keep the interfacial area of thin film solar cells to a minimum value for efficient charge separation as it helps to achieve the desired surface smoothness uniformity for subsequent cadmium sulfide and window layer deposition. This nonvacuum aerosol based approach for making the CIGSSe film uses environmentally benign precursor solution, and it is cheaper for producing solar cells than that of the vacuum-based thin film solar technology. An optimized CIGSSe thin film solar cell with a device configuration of molybdenum-coated soda-lime glass substrate/CIGSSe/CdS/i-ZnO/AZO shows the photovoltaic (j-V) characteristics of Voc=0.518 V, jsc=28.79 mA cm(-2), fill factor=64.02%, and a promising power conversion efficiency of η=9.55% under simulated AM 1.5 100 mW cm(-2) illuminations, without the use of an antireflection layer. This demonstrates the potential of ESAVD deposition as a promising alternative approach for making thin film CIGSSe solar cells at a lower cost.

  17. Improved performance of CdS/CdSe quantum dots sensitized solar cell by incorporation of ZnO nanoparticles/reduced graphene oxide nanocomposite as photoelectrode

    NASA Astrophysics Data System (ADS)

    Ghoreishi, F. S.; Ahmadi, V.; Samadpour, M.

    2014-12-01

    Here we present novel quantum dot sensitized solar cells (QDSSC) based on ZnO nanoparticles (NPs)/reduced graphene oxide (RGO) nanocomposite photoanodes for better light harvesting and energy conversion. Photoelectrodes are prepared by doctor blading ZnO NPs/GO nanocomposite paste on a fluorine doped tin oxide substrate which are then sintered at 450 °C to obtain ZnO NPs/RGO nanocomposites. The partial reduction of GO after thermal reduction, is studied by Fourier transform infrared and Raman spectroscopies. Cadmium sulfide (CdS) and cadmium selenide (CdSe) quantum dots are deposited on the films through successive ionic layer adsorption and reaction and chemical bath deposition methods, respectively. The unique properties of ZnO NPs/RGO photoanodes, lead to a significant enhancement in the photovoltaic properties of solar cells in comparison with bare ZnO photoanodes. Current-voltage characteristics of cells are studied and the best results are obtained from ZnO NPs-RGO/CdS/CdSe with photoelectric conversion efficiency of 2.20% which is almost two times higher than cells which are made by pure ZnO NPs as photoanode (1.28%). Electrochemical impedance measurements show that the enhancement can be attributed to the increase of electron transfer rate in the ZnO NPs/RGO nanocomposite photoanode which arises from the ultrahigh electron mobility in graphene (RGO) sheets.

  18. Crystallinity of Fe-Ni Sulfides in Carbonaceous Chondrites

    NASA Technical Reports Server (NTRS)

    Zolensky, Michael E.; Ohsumi, Kazumasa; Mikouchi, Takashi; Hagiya, Kenji; Le, Loan

    2008-01-01

    The main long-term goal of this research is to understand the physical conditions in the early solar nebula through the detailed characterization of a key class of mineral present in all primitive materials: Fe-Ni sulfides [1&2]. Fe-Ni sulfides can take dozens of structures, depending on the temperature of formation, as well as other physico-chemical factors which are imperfectly understood. Add to this the additional varying factor of Ni content, and we have a potentially sensitive cosmothermometer [3]. Unfortunately, this tool requires exact knowledge of the crystal structure of each grain being considered, and there have been few (none?) studies of the detailed structures of sulfides in chondritic materials. We report here on coordinated compositional and crystallographic investigation of Fe-Ni sulfides in diverse carbonaceous chondrites, initially Acfer 094 (the most primitive CM2 [4]) Tagish Lake (a unique type C2 [5]), a C1 lithology in Kaidun [6], Bali (oxidized CV3 [7]), and Efremovka (reduced CV3 [7]).

  19. Bioaccumulation of cadmium in marine organisms.

    PubMed Central

    Frazier, J M

    1979-01-01

    A general review of cadmium concentrations in marine organisms and studies of cadmium bioaccumulation is presented. Factors which influence cadmium concentrations, such as regional differences, seasonal fluctuations and salinity, are discussed and species which are likely to accumulate cadmium identified. Experimental studies designed to investigate the influence of some of these factors on cadmium bioaccumulation in a filter feeding bivalve mollusk, the American oyster (Crassostrea virginica), are presented. Field studies of seasonal dynamics of cadmium in oysters indicate patterns which may be correlated with seasonal physiological activity. The bioaccumulation of cadmium following input to estuarine systems by natural phenomena is observed. Cadmium concentrations in oysters collected from regions of different salinity suggest an inverse relationship between cadmium concentration and salinity. Laboratory experiments designed to investigate mechanisms of cadmium accumulation demonstrate that an inducible cadmium binding protein, similar to metallothiomein, is present in the American oyster. PMID:488051

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

    PubMed

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

    2014-03-10

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

  1. Quantum-dot-sensitized solar cells: Assembly of CdS-quantum-dots coupling techniques of self-assembled monolayer and chemical bath deposition

    NASA Astrophysics Data System (ADS)

    Lin, Sheng-Chih; Lee, Yuh-Lang; Chang, Chi-Hsiu; Shen, Yu-Jen; Yang, Yu-Min

    2007-04-01

    Two methods, coupling self-assembled monolayer and chemical bath deposition (CBD), were utilized to assemble cadmium sulfide (CdS) quantum dots (QDs) onto mesoporous TiO2 films for dye-sensitized solar cell (DSSC) applications. Colloidal CdS QDs were first self-assembled on the TiO2 surface. CBD was then introduced to replenish the incorporated amount and increase the coverage ratio of CdS QDs on the TiO2 surface. The preassembled CdS QDs act as nucleation sites in the CBD process, forming a CdS nanofilm with an interfacial structure capable of inhibiting the recombination of injected electrons. An efficiency as high as 1.35% for the QD-sensitized DSSC was achieved using the present strategy.

  2. Ti3C2 MXene co-catalyst on metal sulfide photo-absorbers for enhanced visible-light photocatalytic hydrogen production

    PubMed Central

    Ran, Jingrun; Gao, Guoping; Li, Fa-Tang; Ma, Tian-Yi; Du, Aijun; Qiao, Shi-Zhang

    2017-01-01

    Scalable and sustainable solar hydrogen production through photocatalytic water splitting requires highly active and stable earth-abundant co-catalysts to replace expensive and rare platinum. Here we employ density functional theory calculations to direct atomic-level exploration, design and fabrication of a MXene material, Ti3C2 nanoparticles, as a highly efficient co-catalyst. Ti3C2 nanoparticles are rationally integrated with cadmium sulfide via a hydrothermal strategy to induce a super high visible-light photocatalytic hydrogen production activity of 14,342 μmol h−1 g−1 and an apparent quantum efficiency of 40.1% at 420 nm. This high performance arises from the favourable Fermi level position, electrical conductivity and hydrogen evolution capacity of Ti3C2 nanoparticles. Furthermore, Ti3C2 nanoparticles also serve as an efficient co-catalyst on ZnS or ZnxCd1−xS. This work demonstrates the potential of earth-abundant MXene family materials to construct numerous high performance and low-cost photocatalysts/photoelectrodes. PMID:28045015

  3. Ti3C2 MXene co-catalyst on metal sulfide photo-absorbers for enhanced visible-light photocatalytic hydrogen production

    NASA Astrophysics Data System (ADS)

    Ran, Jingrun; Gao, Guoping; Li, Fa-Tang; Ma, Tian-Yi; Du, Aijun; Qiao, Shi-Zhang

    2017-01-01

    Scalable and sustainable solar hydrogen production through photocatalytic water splitting requires highly active and stable earth-abundant co-catalysts to replace expensive and rare platinum. Here we employ density functional theory calculations to direct atomic-level exploration, design and fabrication of a MXene material, Ti3C2 nanoparticles, as a highly efficient co-catalyst. Ti3C2 nanoparticles are rationally integrated with cadmium sulfide via a hydrothermal strategy to induce a super high visible-light photocatalytic hydrogen production activity of 14,342 μmol h-1 g-1 and an apparent quantum efficiency of 40.1% at 420 nm. This high performance arises from the favourable Fermi level position, electrical conductivity and hydrogen evolution capacity of Ti3C2 nanoparticles. Furthermore, Ti3C2 nanoparticles also serve as an efficient co-catalyst on ZnS or ZnxCd1-xS. This work demonstrates the potential of earth-abundant MXene family materials to construct numerous high performance and low-cost photocatalysts/photoelectrodes.

  4. Ti3C2 MXene co-catalyst on metal sulfide photo-absorbers for enhanced visible-light photocatalytic hydrogen production.

    PubMed

    Ran, Jingrun; Gao, Guoping; Li, Fa-Tang; Ma, Tian-Yi; Du, Aijun; Qiao, Shi-Zhang

    2017-01-03

    Scalable and sustainable solar hydrogen production through photocatalytic water splitting requires highly active and stable earth-abundant co-catalysts to replace expensive and rare platinum. Here we employ density functional theory calculations to direct atomic-level exploration, design and fabrication of a MXene material, Ti3C2 nanoparticles, as a highly efficient co-catalyst. Ti3C2 nanoparticles are rationally integrated with cadmium sulfide via a hydrothermal strategy to induce a super high visible-light photocatalytic hydrogen production activity of 14,342 μmol h(-1 )g(-1) and an apparent quantum efficiency of 40.1% at 420 nm. This high performance arises from the favourable Fermi level position, electrical conductivity and hydrogen evolution capacity of Ti3C2 nanoparticles. Furthermore, Ti3C2 nanoparticles also serve as an efficient co-catalyst on ZnS or ZnxCd1-xS. This work demonstrates the potential of earth-abundant MXene family materials to construct numerous high performance and low-cost photocatalysts/photoelectrodes.

  5. A Reaction Involving Oxygen and Metal Sulfides.

    ERIC Educational Resources Information Center

    Hill, William D. Jr.

    1986-01-01

    Describes a procedure for oxygen generation by thermal decomposition of potassium chlorate in presence of manganese dioxide, reacted with various sulfides. Provides a table of sample product yields for various sulfides. (JM)

  6. A Reaction Involving Oxygen and Metal Sulfides.

    ERIC Educational Resources Information Center

    Hill, William D. Jr.

    1986-01-01

    Describes a procedure for oxygen generation by thermal decomposition of potassium chlorate in presence of manganese dioxide, reacted with various sulfides. Provides a table of sample product yields for various sulfides. (JM)

  7. Sulfide Stability of Planetary Basalts

    NASA Technical Reports Server (NTRS)

    Caiazza, C. M.; Righter, K.; Gibson, E. K., Jr.; Chesley, J. T.; Ruiz, J.

    2004-01-01

    The isotopic system, 187Re 187Os, can be used to determine the role of crust and mantle in magma genesis. In order to apply the system to natural samples, we must understand variations in Re/Os concentrations. It is thought that low [Os] and [Re] in basalts can be attributed to sulfide (FeS) saturation, as Re behaves incompatibly to high degrees of evolution until sulfide saturation occurs [1]. Previous work has shown that lunar basalts are sulfide under-saturated, and mid-ocean ridge, ocean-island and Martian (shergottites) basalts are saturated [2,3]. However, little is known about arc basalts. In this study, basaltic rocks were analyzed across the Trans-Mexican Volcanic Belt.

  8. Fabrication and applications of copper sulfide (CuS) nanostructures

    SciTech Connect

    Shamraiz, Umair Hussain, Raja Azadar Badshah, Amin

    2016-06-15

    This review article presents different fabrication procedures (under the headlines of solvothermal routes, aerosol methods, solution methods and thermolysis), and applications (photocatalytic degradation, ablation of cancer cells, electrode material in lithium ion batteries and in gas sensing, organic solar cells, field emission properties, super capacitor applications, photoelectrochemical performance of QDSCs, photocatalytic reduction of organic pollutants, electrochemical bio sensing, enhanced PEC characteristics of pre-annealed CuS film electrodes) of copper sulfide (Covellite). - Highlights: • This review article presents the synthesis and applications of copper sulfide. • CuS has been used over the years for different applications in nanoscience. • Different synthetic protocols are followed for their preparation which help in the possible modifications in the morphology of CuS.

  9. Photovoltaic effect in individual asymmetrically contacted lead sulfide nanosheets.

    PubMed

    Dogan, Sedat; Bielewicz, Thomas; Lebedeva, Vera; Klinke, Christian

    2015-03-21

    Solution-processable, two-dimensional semiconductors are promising optoelectronic materials which could find application in low-cost solar cells. Lead sulfide nanocrystals raised attention since the effective band gap can be adapted over a wide range by electronic confinement and observed multi-exciton generation promises higher efficiencies. We report on the influence of the contact metal work function on the properties of transistors based on individual two-dimensional lead sulfide nanosheets. Using palladium we observed mobilities of up to 31 cm(2) V(-1) s(-1). Furthermore, we demonstrate that asymmetrically contacted nanosheets show photovoltaic effect and that the nanosheets' height has a decisive impact on the device performance. Nanosheets with a thickness of 5.4 nm contacted with platinum and titanium show a power conversion efficiency of up to 0.94% (EQE 75.70%). The results underline the high hopes put on such materials.

  10. Effect of initial sulfide concentration on sulfide and phenol oxidation under denitrifying conditions.

    PubMed

    Beristain-Cardoso, Ricardo; Texier, Anne-Claire; Sierra-Alvarez, Reyes; Razo-Flores, Elías; Field, Jim A; Gómez, J

    2009-01-01

    The objective of this work was to evaluate the effect of the initial sulfide concentration on the kinetics and metabolism of phenol and sulfide in batch bioassays using nitrate as electron acceptor. Complete oxidation of sulfide (20 mg L(-1) of S(2-)) and phenol (19.6 mg L(-1)) was linked to nitrate reduction when nitrate was supplemented at stoichiometric concentrations. At 32 mg L(-1) of sulfide, oxidation of sulfide and phenol by the organo-lithoautotrophic microbial culture was sequential; first sulfide was rapidly oxidized to elemental sulfur and afterwards to sulfate; phenol oxidation started once sulfate production reached a maximum. When the initial sulfide concentration was increased from 20 to 26 and finally to 32 mg L(-1), sulfide oxidation was inhibited. In contrast phenol consumption by the denitrifying culture was not affected. These results indicated that sulfide affected strongly the sulfide oxidation rate and nitrate reduction.

  11. Selected rare earth sulfides in thermoelectric applications

    SciTech Connect

    Raag, V.; Borodovsky, Y.

    1981-01-01

    This paper discusses preliminary results on the preparation and the measurement of thermoelectric properties of various rare earth sulfides of the stoichiometry R/sub 2/S/sub 3/. A preparation method that enables the rapid and predictable preparation of the sulfides has been discussed, along with some preliminary results on the measurement of thermoelectric properties of these sulfides.

  12. 30 CFR 250.808 - Hydrogen sulfide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 2 2011-07-01 2011-07-01 false Hydrogen sulfide. 250.808 Section 250.808... Safety Systems § 250.808 Hydrogen sulfide. Production operations in zones known to contain hydrogen sulfide (H2S) or in zones where the presence of H2S is unknown, as defined in § 250.490 of this...

  13. 30 CFR 250.504 - Hydrogen sulfide.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.504 Section 250.504... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Well-Completion Operations § 250.504 Hydrogen sulfide. When a well-completion operation is conducted in zones known to contain hydrogen sulfide (H2S) or...

  14. 30 CFR 250.604 - Hydrogen sulfide.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.604 Section 250.604... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Well-Workover Operations § 250.604 Hydrogen sulfide. When a well-workover operation is conducted in zones known to contain hydrogen sulfide (H2S) or...

  15. 30 CFR 250.808 - Hydrogen sulfide.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.808 Section 250.808... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Production Safety Systems § 250.808 Hydrogen sulfide. Production operations in zones known to contain hydrogen sulfide (H2S) or in zones where the presence of...

  16. 30 CFR 250.808 - Hydrogen sulfide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 2 2014-07-01 2014-07-01 false Hydrogen sulfide. 250.808 Section 250.808 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL... § 250.808 Hydrogen sulfide. Production operations in zones known to contain hydrogen sulfide (H2S) or in...

  17. 30 CFR 250.808 - Hydrogen sulfide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 2 2012-07-01 2012-07-01 false Hydrogen sulfide. 250.808 Section 250.808 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL... § 250.808 Hydrogen sulfide. Production operations in zones known to contain hydrogen sulfide (H2S) or in...

  18. 30 CFR 250.808 - Hydrogen sulfide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 2 2013-07-01 2013-07-01 false Hydrogen sulfide. 250.808 Section 250.808 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL... § 250.808 Hydrogen sulfide. Production operations in zones known to contain hydrogen sulfide (H2S) or in...

  19. Nanostructured metal sulfides for energy storage

    NASA Astrophysics Data System (ADS)

    Rui, Xianhong; Tan, Huiteng; Yan, Qingyu

    2014-08-01

    Advanced electrodes with a high energy density at high power are urgently needed for high-performance energy storage devices, including lithium-ion batteries (LIBs) and supercapacitors (SCs), to fulfil the requirements of future electrochemical power sources for applications such as in hybrid electric/plug-in-hybrid (HEV/PHEV) vehicles. Metal sulfides with unique physical and chemical properties, as well as high specific capacity/capacitance, which are typically multiple times higher than that of the carbon/graphite-based materials, are currently studied as promising electrode materials. However, the implementation of these sulfide electrodes in practical applications is hindered by their inferior rate performance and cycling stability. Nanostructures offering the advantages of high surface-to-volume ratios, favourable transport properties, and high freedom for the volume change upon ion insertion/extraction and other reactions, present an opportunity to build next-generation LIBs and SCs. Thus, the development of novel concepts in material research to achieve new nanostructures paves the way for improved electrochemical performance. Herein, we summarize recent advances in nanostructured metal sulfides, such as iron sulfides, copper sulfides, cobalt sulfides, nickel sulfides, manganese sulfides, molybdenum sulfides, tin sulfides, with zero-, one-, two-, and three-dimensional morphologies for LIB and SC applications. In addition, the recently emerged concept of incorporating conductive matrices, especially graphene, with metal sulfide nanomaterials will also be highlighted. Finally, some remarks are made on the challenges and perspectives for the future development of metal sulfide-based LIB and SC devices.

  20. Nanostructured metal sulfides for energy storage.

    PubMed

    Rui, Xianhong; Tan, Huiteng; Yan, Qingyu

    2014-09-07

    Advanced electrodes with a high energy density at high power are urgently needed for high-performance energy storage devices, including lithium-ion batteries (LIBs) and supercapacitors (SCs), to fulfil the requirements of future electrochemical power sources for applications such as in hybrid electric/plug-in-hybrid (HEV/PHEV) vehicles. Metal sulfides with unique physical and chemical properties, as well as high specific capacity/capacitance, which are typically multiple times higher than that of the carbon/graphite-based materials, are currently studied as promising electrode materials. However, the implementation of these sulfide electrodes in practical applications is hindered by their inferior rate performance and cycling stability. Nanostructures offering the advantages of high surface-to-volume ratios, favourable transport properties, and high freedom for the volume change upon ion insertion/extraction and other reactions, present an opportunity to build next-generation LIBs and SCs. Thus, the development of novel concepts in material research to achieve new nanostructures paves the way for improved electrochemical performance. Herein, we summarize recent advances in nanostructured metal sulfides, such as iron sulfides, copper sulfides, cobalt sulfides, nickel sulfides, manganese sulfides, molybdenum sulfides, tin sulfides, with zero-, one-, two-, and three-dimensional morphologies for LIB and SC applications. In addition, the recently emerged concept of incorporating conductive matrices, especially graphene, with metal sulfide nanomaterials will also be highlighted. Finally, some remarks are made on the challenges and perspectives for the future development of metal sulfide-based LIB and SC devices.