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Sample records for cadmium telluride photovoltaic

  1. Brief review of cadmium telluride-based photovoltaic technologies

    Science.gov (United States)

    Başol, Bülent M.; McCandless, Brian

    2014-01-01

    Cadmium telluride (CdTe) is the most commercially successful thin-film photovoltaic technology. Development of CdTe as a solar cell material dates back to the early 1980s when ˜10% efficient devices were demonstrated. Implementation of better quality glass, more transparent conductive oxides, introduction of a high-resistivity transparent film under the CdS junction-partner, higher deposition temperatures, and improved Cl-treatment, doping, and contacting approaches yielded >16% efficient cells in the early 2000s. Around the same time period, use of a photoresist plug monolithic integration process facilitated the demonstration of the first 11% efficient module. The most dramatic advancements in CdTe device efficiencies were made during the 2013 to 2014 time frame when small-area cell conversion efficiency was raised to 20% range and a champion module efficiency of 17% was reported. CdTe technology is attractive in terms of its limited life-cycle greenhouse gas and heavy metal emissions, small carbon footprint, and short energy payback times. Limited Te availability is a challenge for the growth of this technology unless Te utilization rates are greatly enhanced along with device efficiencies.

  2. Thin-film cadmium telluride photovoltaics: ES and H issues, solutions, and perspectives

    International Nuclear Information System (INIS)

    Photovoltaics (PV) is a growing business worldwide, with new technologies evolving towards potentially large-volume production. PV use produces no emissions, thus offsetting many potential environmental problems. However, the new PV technologies also bring unfamiliar environment, safety, and health (ES and H) challenges that require innovative solutions. This is a summary of the issues, solutions, and perspectives associated with the use of cadmium in one of the new and important PV technologies: thin-film, cadmium telluride (CdTe) PV, which is being developed and commercialized by several companies including Solar Cells Inc. (Toledo, Ohio), BP Solar (Fairfield, California), and Matsushita (Japan). The principal ES and H issue for thin-film cadmium telluride PV is the potential introduction of cadmium--a toxic heavy metal--into the air or water. The amount of cadmium in thin-film PV, however, is quite small--one nickel cadmium flashlight battery has about as much cadmium (7 g) as a square meter of PV module using current technology--and a typical cordless power tool will have 5--10 batteries. CdTe modules are also very well sealed, limiting the chance of release. Nonetheless, minimizing the amount of cadmium in cadmium telluride modules and preventing the introduction of that cadmium into the environment is a top priority for National Renewable Energy Laboratory researchers and cadmium telluride PV manufacturers

  3. Method of making a thin film cadmium telluride solar cell

    International Nuclear Information System (INIS)

    A method for making a photovoltaic cell is described comprising the steps of: (a) depositing a transparent or semi-transparent conductive window layer onto a substrate; (b) depositing a layer of cadmium telluride including phosphorus onto the window layer; (c) depositing a layer of lead telluride onto the layer of cadmium telluride; and (d) depositing a metallic electrode onto the lead telluride layer

  4. Regulatory policy governing cadmium-telluride photovoltaics: A case study contrasting life cycle management with the precautionary principle

    International Nuclear Information System (INIS)

    Market projections for cadmium-telluride (CdTe) thin-film photovoltaics (PV) are tempered by global environmental policies based on the precautionary principle which restrict electronic products containing cadmium, a known human carcinogen. An alternative to the precautionary principle is life cycle management, which involves manufacturers assuming product stewardship from beginning to end of product life. Both approaches have the aim of minimizing environmental contamination, but attempt to do so in different ways. Restrictions on electronic products containing cadmium by the precautionary principle-based restriction of hazardous substances (RoHS) directive in the European Union and a similar policy in China are presented, relative to their potential impact on CdTe PV. Life cycle environmental risks with respect to potential release of cadmium to the environment are also presented for routine operation of CdTe PV panels, potential catastrophic release of cadmium from a residential fire, and at the end of the product life. There is negligible risk of environmental cadmium contamination during routine operation and insignificant risk during catastrophic exposure events such as fire. At the end of the product life, risks of contamination are minimized by take-back programs that may be paid for by insurance premiums incorporated into the cost of the product. Therefore, policies based on the precautionary principle that could potentially ban the product based on its cadmium content may not be warranted

  5. Physical characterization of cadmium telluride/cadmium sulfide photovoltaics: Defects, fields, and micrononuniformities

    Science.gov (United States)

    Shvydka, Diana

    Recent advances in large area thin-film photovoltaic manufacturing have raised a number of problems related to the physical parameters and processes behind the device efficiency and stability. The characteristics of interest include the defect spectra and related optical absorption, the built-in electric field distribution, the degree of lateral uniformity of the device, and the device stability. Established in this thesis is a set of techniques appropriate for the physical characterization of the above features in CdTe/CdS solar cells, addressing the issues of device spectra vs. energy (as revealed in the optical absorption, photoluminescence (PL), and admittance spectroscopy); the electric field distribution analyzed by means of bias dependent PL, and, indirectly, by capacitance measurements; device lateral resistivity and uniformity, through the phenomenon of nonlocal optical response and PL mapping; local parameter fluctuations as appear in virtually all of the above cases. The most important physical conclusions made are: energy spectra of polycrystalline CdTe based photovoltaics combine the features of crystalline materials, such as identifiable point defects, and amorphous materials, which exhibit continuous spectra of localized states; the concept of a single-defect (elemental) capacitance is for the first time defined and applied to estimate the density of states in polycrystalline p-n junctions; a phenomenon of bias-dependent PL in CdTe based photovoltaics is for the first time observed and modeled; a new phenomenon of nonlocal photovoltaic response is observed and interpreted. The results suggest several practical applications, such as: absorption and PL measurements as a diagnostic tool for monitoring the CdCl2, quality of treatments; admittance spectroscopy techniques to diagnose the material quality and degradation through its defect spectra and concentration; bias-dependent PL as a sensitive nondestructive accelerated life testing tool; nonlocal PV

  6. Polycrystalline Thin-Film Research: Cadmium Telluride (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2011-06-01

    Capabilities fact sheet that includes scope, core competencies and capabilities, and contact/web information for Polycrystalline Thin-Film Research: Cadmium Telluride at the National Center for Photovoltaics.

  7. Derived reference doses for three compounds used in the photovoltaics industry: Copper indium diselenide, copper gallium diselenide, and cadmium telluride

    Energy Technology Data Exchange (ETDEWEB)

    Moskowitz, P.D.; Bernholc, N.; DePhillips, M.P.; Viren, J.

    1995-07-06

    Polycrystalline thin-film photovoltaic modules made from copper indium diselenide (CIS), copper gallium diselenide (CGS), and cadmium telluride (CdTe) arc nearing commercial development. A wide range of issues are being examined as these materials move from the laboratory to large-scale production facilities to ensure their commercial success. Issues of traditional interest include module efficiency, stability and cost. More recently, there is increased focus given to environmental, health and safety issues surrounding the commercialization of these same devices. An examination of the toxicological properties of these materials, and their chemical parents is fundamental to this discussion. Chemicals that can present large hazards to human health or the environment are regulated often more strictly than those that are less hazardous. Stricter control over how these materials are handled and disposed can increase the costs associated with the production and use of these modules dramatically. Similarly, public perception can be strongly influenced by the inherent biological hazard that these materials possess. Thus, this report: presents a brief background tutorial on how toxicological data are developed and used; overviews the toxicological data available for CIS, CGS and CdTe; develops ``reference doses`` for each of these compounds; compares the reference doses for these compounds with those of their parents; discusses the implications of these findings to photovoltaics industry.

  8. Cadmium telluride nuclear radiation detectors

    International Nuclear Information System (INIS)

    The characteristics and performance of undoped high resistivity cadmium telluride detectors are compared to chlorine lifted counters. It is shown, in particular, that Undodep CdTe is in fact aluminium doped and that compensation occurs, as an silicon or germanium, by pair and triplet formation between the group III donor and the doubly charged cadmium vacancy acceptor. Furthermore, in chlorine doped samples, the polarization effect results from the unpaired level at Esub(c)-0,6eV

  9. Modelling of illuminated current–voltage characteristics to evaluate leakage currents in long wavelength infrared mercury cadmium telluride photovoltaic detectors

    Energy Technology Data Exchange (ETDEWEB)

    Gopal, Vishnu, E-mail: vishnu-46@yahoo.com, E-mail: wdhu@mail.sitp.ac.cn [Institute of Defence Scientists and Technologists, CFEES Complex, Brig. S. K. Majumdar Marg, Delhi 110054 (India); Qiu, WeiCheng; Hu, Weida, E-mail: vishnu-46@yahoo.com, E-mail: wdhu@mail.sitp.ac.cn [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China)

    2014-11-14

    The current–voltage characteristics of long wavelength mercury cadmium telluride infrared detectors have been studied using a recently suggested method for modelling of illuminated photovoltaic detectors. Diodes fabricated on in-house grown arsenic and vacancy doped epitaxial layers were evaluated for their leakage currents. The thermal diffusion, generation–recombination (g-r), and ohmic currents were found as principal components of diode current besides a component of photocurrent due to illumination. In addition, both types of diodes exhibited an excess current component whose growth with the applied bias voltage did not match the expected growth of trap-assisted-tunnelling current. Instead, it was found to be the best described by an exponential function of the type, I{sub excess} = I{sub r0} + K{sub 1} exp (K{sub 2} V), where I{sub r0}, K{sub 1}, and K{sub 2} are fitting parameters and V is the applied bias voltage. A study of the temperature dependence of the diode current components and the excess current provided the useful clues about the source of origin of excess current. It was found that the excess current in diodes fabricated on arsenic doped epitaxial layers has its origin in the source of ohmic shunt currents. Whereas, the source of excess current in diodes fabricated on vacancy doped epitaxial layers appeared to be the avalanche multiplication of photocurrent. The difference in the behaviour of two types of diodes has been attributed to the difference in the quality of epitaxial layers.

  10. Thin-film cadmium telluride photovoltaic cells. Final subcontract report, 1 November 1992--1 January 1994

    Energy Technology Data Exchange (ETDEWEB)

    Compaan, A.D.; Bohn, R.G. [Toledo Univ., OH (United States)

    1994-09-01

    This report describes work to develop and optimize radio-frequency (rf) sputtering for the deposition of thin films of cadmium telluride (CdTe) and related semiconductors for thin-film solar cells. Pulsed laser physical vapor deposition was also used for exploratory work on these materials, especially where alloying or doping are involved, and for the deposition of cadmium chloride layers. The sputtering work utilized a 2-in diameter planar magnetron sputter gun. The film growth rate by rf sputtering was studied as a function of substrate temperature, gas pressure, and rf power. Complete solar cells were fabricated on tin-oxide-coated soda-lime glass substrates. Currently, work is being done to improve the open-circuit voltage by varying the CdTe-based absorber layer, and to improve the short-circuit current by modifying the CdS window layer.

  11. Cadmium zinc telluride spectral modeling

    International Nuclear Information System (INIS)

    Cadmium zinc telluride (CZT) detectors are the highest resolution room temperature gamma-ray detectors available for isotopic analysis. As with germanium detectors, accurate isotopic analysis using spectra requires peak deconvolution. The CZT peak shapes are asymmetric, with a long low energy tail. The asymmetry is a result of the physics of the electron/hole transport in the semiconductor. An accurate model of the physics of the electron/hole transport through an electric field will allow the parameterization of the peak shapes as a function of energy. In turn this leads to the ability to perform accurate spectral deconvolution and therefore accurate isotopic analysis. The model and the peak-shape parameterization as a function of energy will be presented

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

    Energy Technology Data Exchange (ETDEWEB)

    Chu, T.L. (University of South Florida, Tampa, FL (United States))

    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. Transient Response of Cadmium Telluride Modules to Light Exposure: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Deline, C.; del Cueto, J.; Albin, D. S.; Petersen, C.; Tyler, L.; TamizhMani, G.

    2011-07-01

    Commercial cadmium telluride (CdTe) photovoltaic (PV) modules from three different manufacturers were monitored for performance changes during indoor and outdoor light-exposure. Short-term transients in Voc were recorded on some modules, with characteristic times of ~1.1 hours. Outdoor performance data shows a similar drop in Voc after early morning light exposure. Preliminary analysis of FF changes show light-induced changes on multiple time scales, including a long time scale.

  14. High-efficiency, thin-film cadmium telluride photovoltaic cells. Annual subcontract report, 20 January 1994--19 January 1995

    Energy Technology Data Exchange (ETDEWEB)

    Compaan, A.D.; Bohn, R.G.; Rajakarunanayake, Y. [Toledo Univ., OH (United States)

    1995-08-01

    This report describes work performed to develop and optimize the process of radio frequency (RF) sputtering for the fabrication of thin-film solar cells on glass. The emphasis is on CdTe-related materials including CdTe, CdS, ZnTe, and ternary alloy semiconductors. Pulsed laser physical vapor deposition (LPVD) was used for exploratory work on these materials, especially where alloying or doping are involved, and for the deposition of cadmium chloride layers. For the sputtering work, a two-gun sputtering chamber was implemented, with optical access for monitoring temperature and growth rate. We studied the optical and electrical properties of the plasmas produced by two different kinds of planar magnetron sputter guns with different magnetic field configurations and strengths. Using LPVD, we studied alloy semiconductors such as CdZnTe and heavily doped semiconductors such as ZnTe:Cu for possible incorporation into graded band gap CdTe-based photovoltaic devices.

  15. Thin-film cadmium telluride solar cells

    Science.gov (United States)

    Chu, T. L.

    1987-10-01

    Cadmium telluride, with a room-temperature band-gap energy of 1.5 eV, is a promising thin-film photovoltaic material. The major objective of this research has been to demonstrate thin-film CdTe heterojunction solar cells with a total area greater than 1 sq cm and photovoltaic efficiencies of 13 percent or more. Thin-film p-CdTe/CdS/SnO2:F/glass solar cells with an AM1.5 efficiency of 10.5 percent have been reported previously. This report contains results of work done on: (1) the deposition, resistivity control, and characterization of p-CdTe films by the close-spaced sublimation process; (2) the deposition of large-band-gap window materials; (3) the electrical properties of CdS/CdTe heterojunctions; (4) the formation of stable, reproducible, ohmic contacts (such as p-HgTe) to p-CdTe; and (5) the preparation and evaluation of heterojunction solar cells.

  16. Cadmium telluride quantum dots advances and applications

    CERN Document Server

    Donegan, John

    2013-01-01

    Optical Properties of Bulk and Nanocrystalline Cadmium Telluride, Núñez Fernández and M.I. VasilevskiyAqueous Synthesis of Colloidal CdTe Nanocrystals, V. Lesnyak, N. Gaponik, and A. EychmüllerAssemblies of Thiol-Capped CdTe Nanocrystals, N. GaponikFörster Resonant Energy Transfer in CdTe Nanocrystal Quantum Dot Structures, M. Lunz and A.L. BradleyEmission of CdTe Nanocrystals Coupled to Microcavities, Y.P. Rakovich and J.F. DoneganBiological Applications of Cadmium Telluride Semiconductor Quantum Dots, A. Le Cign

  17. Electron mobility in mercury cadmium telluride

    Science.gov (United States)

    Patterson, James D.

    1988-01-01

    A previously developed program, which includes all electronic interactions thought to be important, does not correctly predict the value of electron mobility in mercury cadmium telluride particularly near room temperature. Part of the reason for this discrepancy is thought to be the way screening is handled. It seems likely that there are a number of contributors to errors in the calculation. The objective is to survey the calculation, locate reasons for differences between experiment and calculation, and suggest improvements.

  18. Numerical Simulation of the Performance Characteristics, Instability, and Effects of Band Gap Grading in Cadmium Telluride Based Photovoltaic Devices

    Energy Technology Data Exchange (ETDEWEB)

    Michael David Petersen

    2001-06-27

    Using computer simulations, the performance of several CdTe based photovoltaic structures has been studied. The advantages and disadvantages of band gap grading, through the use of (Zn, Cd)Te, have also been investigated in these structures. Grading at the front interface between a CdS window layer and a CdTe absorber layer, can arise due to interdiffusion between the materials during growth or due to the intentional variation of the material composition. This grading has been shown to improve certain performance metrics, such as the open-circuit voltage, while degrading others, such as the fill factor, depending on the amount and distance of the grading. The presence of a Schottky barrier as the back contact has also been shown to degrade the photovoltaic performance of the device, resulting in a characteristic IV curve. However, with the appropriate band gap grading at the back interface, it has been shown that the performance can be enhanced through more efficient carrier collection. These results were then correlated with experimental observations of the performance degradation in devices subjected to light and heat stress.

  19. Numerical Simulation of the Performance Characteristics, Instability, and Effects of Band Gap Grading in Cadmium Telluride Based Photovoltaic Devices

    Energy Technology Data Exchange (ETDEWEB)

    Michael David Petersen

    2001-05-01

    Using computer simulations, the performance of several CdTe based photovoltaic structures has been studied. The advantages and disadvantages of band gap grading, through the use of (Zn,Cd)Te, have also been investigated in these structures. Grading at the front interface between a CdS window layer and a CdTe absorber layer, can arise due to interdiffusion between the materials during growth or due to the intentional variation of the material composition. This grading has been shown to improve certain performance metrics, such as the open-circuit voltage, while degrading others, such as the fill factor, depending on the amount and distance of the grading. The presence of a Schottky barrier as the back contact has also been shown to degrade the photovoltaic performance of the device, resulting in a characteristic IV curve. However, with the appropriate band gap grading at the back interface, it has been shown that the performance can be enhanced through more efficient carrier collection. These results were then correlated with experimental observations of the performance degradation in devices subjected to light and heat stress.

  20. High-efficiency thin-film cadmium telluride photovoltaic cells. Annual technical report, January 20, 1996--January 19, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Compaan, A D; Bohn, R G; Contreras-Puente, G [Univ. of Toledo, OH (United States)

    1997-08-01

    The University of Toledo photovoltaics group has been instrumental in developing rf sputtering for CDs/CdTe thin-film solar cells. During the third phase of the present contract our work focussed on efforts to determine factors which limit the efficiency in our {open_quotes}all-sputtered{close_quotes} thin-film CdTe solar cells on soda-lime glass. We find that our all-sputtered cells, which are deposited at substantially lower temperature than those by sublimation or vapor deposition, require less aggressive CdCl{sub 2} treatments than do other deposition techniques and this is presumably related to CDs/CdTe interdiffusion. The CDs/CdTe interdiffusion process has been studied by several methods, including photoluminescence and capacitance-voltage measurements. Furthermore, we have deposited special thin bilayer films on quartz and borosilicate glass. Interdiffusion in these thin bilayers have been probed by Rutherford backscattering, with collaborators at Case Western Reserve University, and grazing incidence x-ray scattering (GIXS), with collaborators at the University at Buffalo and Brookhaven National Lab. Also, in order better to understand the properties of the ternary alloy material, we used laser physical vapor deposition to prepare a series of CdS{sub x}Te{sub 1-x} films on borosilicate glass. The composition of the alloy films was determined by wavelength dispersive x-ray spectroscopy at NREL. These films are currently being investigated by us and other groups at NREL and IEC.

  1. Effects of nanoassembly on the optoelectronic properties of cadmium telluride - zinc oxide nanocomposite thin films for use in photovoltaic devices

    Science.gov (United States)

    Beal, Russell Joseph

    Quantum-scale semiconductors embedded in an electrically-active matrix have the potential to improve photovoltaic (PV) device power conversion efficiencies by allowing the solar spectral absorption and photocarrier transport properties to be tuned through the control of short and long range structure. In the present work, the effects of phase assembly on quantum confinement effects and carrier transport were investigated in CdTe - ZnO nanocomposite thin films for use as a spectrally sensitized n-type heterojunction element. The nanocomposites were deposited via a dual-source, sequential radio-frequency (RF) sputter technique that offers the unique opportunity for in-situ control of the CdTe phase spatial distribution within the ZnO matrix. The manipulation of the spatial distribution of the CdTe nanophase allowed for variation in the electromagnetic coupling interactions between semiconductor domains and accompanying changes in the effective carrier confinement volume and associated spectral absorption properties. Deposition conditions favoring CdTe connectivity had a red shift in absorption energy onset in comparison to phase assemblies with a more isolated CdTe phase. While manipulating the absorption properties is of significant interest, the electronic behavior of the nanocomposite must also be considered. The continuity of both the matrix and the CdTe influenced the mobility pathways for carriers generated within their respective phases. Photoconductivity of the nanocomposite, dependent upon the combined influences of nanostructure-mediated optical absorption and carrier transport path, increased with an increased semiconductor nanoparticle number density along the applied field direction. Mobility of the carriers in the nanocomposite was further mediated by the interface between the ZnO and CdTe nanophases which acts as a source of carrier scattering centers. These effects were influenced by low temperature annealing of the nanocomposite which served to

  2. Avalanche multiplication of electrons and holes in cadmium telluride

    CERN Document Server

    Demich, N V

    2001-01-01

    Determination of the ratio of the coefficients of the electrons and holes of the diode structures impact ionization is carried out with the purpose of optimizing the parameters of the avalanche diodes from the cadmium telluride. It is shown experimentally, that the process of the impact ionization in the cadmium telluride is stimulated by holes. The ratio of the coefficients of the holes and electrons impact ionization constitutes approx = 30-40

  3. Landfill waste and recycling: Use of a screening-level risk assessment tool for end-of-life cadmium telluride (CdTe) thin-film photovoltaic (PV) panels

    International Nuclear Information System (INIS)

    Grid-connected solar photovoltaic (PV) power is currently one of the fastest growing power-generation technologies in the world. While PV technologies provide the environmental benefit of zero emissions during use, the use of heavy metals in thin-film PV cells raises important health and environmental concerns regarding the end-of-life disposal of PV panels. To date, there is no published quantitative assessment of the potential human health risk due to cadmium leaching from cadmium telluride (CdTe) PV panels disposed in a landfill. Thus, we used a screening-level risk assessment tool to estimate possible human health risk associated with disposal of CdTe panels into landfills. In addition, we conducted a literature review of potential cadmium release from the recycling process in order to contrast the potential health risks from PV panel disposal in landfills to those from PV panel recycling. Based on the results of our literature review, a meaningful risk comparison cannot be performed at this time. Based on the human health risk estimates generated for PV panel disposal, our assessment indicated that landfill disposal of CdTe panels does not pose a human health hazard at current production volumes, although our results pointed to the importance of CdTe PV panel end-of-life management. - Highlights: • Analysis of possible human health risk posed by disposal of CdTe panels into landfills. • Qualitative comparison of risks associated with landfill disposal and recycling of CdTe panels. • Landfill disposal of CdTe panels does not pose a human health hazard at current production volumes. • There could be potential risks associated with recycling if not properly managed. • Factors other than concerns over toxic substances will likely drive the decisions of how to manage end-of-life PV panels

  4. Thin films and solar cells of cadmium telluride and cadmium zinc telluride

    Energy Technology Data Exchange (ETDEWEB)

    Ferekides, C.S.

    1991-01-01

    The objectives of this dissertation are to investigate (1) the metalorganic chemical vapor deposition (MOCVD) and properties of cadmium telluride (CdTe) and cadmium zinc telluride (Cd(1-x)Zn(z)Te) films and junctions, and their potential application to solar cells, and (2) the fabrication and characterization of CdTe solar cells by the close spaced sublimation (CSS) technique. CdTe and Cd(1-x)Zn(x)Te films have been deposited by MOCVD on a variety of substrates at 300-400 C.The effect of the deposition parameters and post deposition heat treatments on the electrical, optical, and structural properties have been investigated. Heterojunctions of the configuration CdTe/transparent conducting semiconductor (TCS) and Cd(1-x)Zn(x)Te/TCS have been prepared and characterized. CdTe(MOCVD)/CdS and Cd(1-x)Zn(x)Te(E sub g = 1.65eV)/Cd(1-x)Zn(x)S solar cells with efficiencies of 9.9 percent and 2.4 percent, respectively have been fabricated. The as-deposited CdTe(MOCVD)/CdS junctions exhibited high dark current densities due to deflects at the interface associated with small grain size. No effective post-deposition heat treatment has been developed. CdTe/CdS solar cells have also been fabricated by the close spaced sublimation (CSS). Significant improvements in material and processing have been made, and in collaboration with fellow researchers an AM1.5 conversion efficiency of 13.4 percent has been demonstrated, the highest efficiency ever measured for such devices. The highest conversion efficiency for the CdTe(CSS)/CdS solar cell was achieved by reaching high open-circuit voltages and fill factors, while the short-circuit current densities were moderate. These results indicate that further improvements to increase the short-circuit current densities can result in conversion efficiencies over 15 percent.

  5. Review of the field performance of one cadmium telluride module

    Energy Technology Data Exchange (ETDEWEB)

    Cueto, J.A. del [National Renewable Energy Lab., Golden, CO (United States)

    1998-12-01

    Performance data gathered in situ from a large-area cadmium telluride (CdTe) thin-film photovoltaic (PV) module that has been deployed outdoors since February 1995 are investigated. It appears that the module's performance has been stable over the last 2 years but it exhibits a semi-cyclical variation whereby the efficiency appears to peak between the autumnal equinox and winter solstice. Analyses are performed that dissect module current-voltage parameters by irradiance and examine their dependence on temperature. The temperature coefficient of the efficiency is quite small and negative from 80% of 1-sun intensity and upwards. Its meager value is the outcome of the sizes and opposite sings of the temperature coefficients of the open-circuit voltage and fill factor. Average module series resistance is quantified and shown to be a determinant in power loss of 11% at 1-sun intensity. It is demonstrated to constrain the fill factor at illumination intensities above 60% of 1-sun, which occurs in the same range of illumination intensities that the temperature coefficients of the fill factor exhibit positive values. Evidence is presented that points to some spectrally-induced variations in the efficiency. (Author)

  6. Thin film cadmium telluride, zinc telluride, and mercury zinc telluride solar cells. Final subcontract report, 1 July 1988--31 December 1991

    Energy Technology Data Exchange (ETDEWEB)

    Chu, T.L. [University of South Florida, Tampa, FL (United States)

    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.

  7. The Cadmium Zinc Telluride Imager on AstroSat

    CERN Document Server

    Bhalerao, V; Vibhute, A; Pawar, P; Rao, A R; Hingar, M K; Khanna, Rakesh; Kutty, A P K; Malkar, J P; Patil, M H; Arora, Y K; Sinha, S; Priya, P; Samuel, Essy; Sreekumar, S; Vinod, P; Mithun, N P S; Vadawale, S V; Vagshette, N; Navalgund, K H; Sarma, K S; Pandiyan, R; Seetha, S; Subbarao, K

    2016-01-01

    The Cadmium Zinc Telluride Imager (CZTI) is a high energy, wide-field imaging instrument on AstroSat. CZT's namesake Cadmium Zinc Telluride detectors cover an energy range from 20 keV to > 200 keV, with 11% energy resolution at 60 keV. The coded aperture mask attains an angular resolution of 17' over a 4.6 deg x 4.6 deg (FWHM) field of view. CZTI functions as an open detector above 100 keV, continuously sensitive to GRBs and other transients in about 30% of the sky. The pixellated detectors are sensitive to polarisation above ~100 keV, with exciting possibilities for polarisation studies of transients and bright persistent sources. In this paper, we provide details of the complete CZTI instrument, detectors, coded aperture mask, mechanical and electronic configuration, as well as data and products.

  8. Predeposition ultraviolet treatment for adhesion improvement of thin films on mercury cadmium telluride

    International Nuclear Information System (INIS)

    Poor film adhesion to mercury cadmium telluride is a problem of general concern because of the low film deposition temperatures (11 cm-2 and slow interface state densities of 4x1010 cm-2 were obtained at 100 K for aluminum nitiride/mercury cadmium telluride metal-insulator-semiconductor structures which had undergone the treatment

  9. Removal of CdTe in acidic media by magnetic ion-exchange resin: A potential recycling methodology for cadmium telluride photovoltaic waste

    International Nuclear Information System (INIS)

    Highlights: • Sulfonated magnetic microsphere was prepared as one strong acid cation-exchange resin. • Cd and Te can be removed directly from the highly acidic leaching solution of CdTe. • Good chemical stability, fast adsorbing rate and quick magnetic separation in strong acidic media. • A potential path for recycling CdTe photovoltaic waste. - Abstract: Sulfonated magnetic microspheres (PSt-DVB-SNa MPs) have been successfully prepared as adsorbents via an aqueous suspension polymerization of styrene-divinylbenzene and a sulfonation reaction successively. The resulting adsorbents were confirmed by means of Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS) and vibrating sample magnetometer (VSM). The leaching process of CdTe was optimized, and the removal efficiency of Cd and Te from the leaching solution was investigated. The adsorbents could directly remove all cations of Cd and Te from a highly acidic leaching solution of CdTe. The adsorption process for Cd and Te reached equilibrium in a few minutes and this process highly depended on the dosage of adsorbents and the affinity of sulfonate groups with cations. Because of its good adsorption capacity in strong acidic media, high adsorbing rate, and efficient magnetic separation from the solution, PSt-DVB-SNa MPs is expected to be an ideal material for the recycling of CdTe photovoltaic waste

  10. Removal of CdTe in acidic media by magnetic ion-exchange resin: A potential recycling methodology for cadmium telluride photovoltaic waste

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Teng, E-mail: zhangteng@mail.iee.ac.cn; Dong, Zebin; Qu, Fei; Ding, Fazhu; Peng, Xingyu; Wang, Hongyan; Gu, Hongwei

    2014-08-30

    Highlights: • Sulfonated magnetic microsphere was prepared as one strong acid cation-exchange resin. • Cd and Te can be removed directly from the highly acidic leaching solution of CdTe. • Good chemical stability, fast adsorbing rate and quick magnetic separation in strong acidic media. • A potential path for recycling CdTe photovoltaic waste. - Abstract: Sulfonated magnetic microspheres (PSt-DVB-SNa MPs) have been successfully prepared as adsorbents via an aqueous suspension polymerization of styrene-divinylbenzene and a sulfonation reaction successively. The resulting adsorbents were confirmed by means of Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS) and vibrating sample magnetometer (VSM). The leaching process of CdTe was optimized, and the removal efficiency of Cd and Te from the leaching solution was investigated. The adsorbents could directly remove all cations of Cd and Te from a highly acidic leaching solution of CdTe. The adsorption process for Cd and Te reached equilibrium in a few minutes and this process highly depended on the dosage of adsorbents and the affinity of sulfonate groups with cations. Because of its good adsorption capacity in strong acidic media, high adsorbing rate, and efficient magnetic separation from the solution, PSt-DVB-SNa MPs is expected to be an ideal material for the recycling of CdTe photovoltaic waste.

  11. The photocorrosion of n-cadmium telluride and its suppression

    Science.gov (United States)

    Curran, J. S.

    1980-09-01

    The photoelectrochemical properties of n-type cadmium telluride were studied in water and five other organic solvents, with a view to suppression of the photocorrosion reaction which prevents this and other n-type small bandgap semiconductors from being used in a practical semiconductor-electrolyte junction solar cell. Only the low donicity organic solvents propylene carbonate and methyl nitrate reduce the corrosion rate significantly. A stable photocurrent can be obtained using a solution of ferrocene in these two solvents but analysis of photoelectrolyzed solutions revealed a slow photocorrosion. The dependence of the flatband potential and of the practical significance with respect to solar cell applications considered.

  12. An evaluation of cadmium telluride detectors for computer assisted tomography.

    Science.gov (United States)

    Chu, D; Kaufman, L; Hosier, K; Hoenninger, J

    1978-11-01

    Cadmium telluride (CdTe) presents a set of extremely attractive features as an X-ray detector for computer assisted tomography (CAT). It is stable and easily handled; has a high detection efficiency and very efficient conversion of energy to charge; and permits a high element density in a compact configuration. Unfortunately, effects due to "polarization," "tailing," high and variable leakage currents, and long "memory" are incompatible with the needs of CAT instrumentation. Pulse-processing techniques have allowed us to eliminate these problems in positive-sensitive detectors, thus opening the way for utilization of CdTe in CAT. PMID:711945

  13. Surface Passivation of Mercury-Cadmium-Telluride Infrared Detectors

    Directory of Open Access Journals (Sweden)

    R. Singh

    1991-07-01

    Full Text Available The theoretical considerations and practical aspects of passivating insulator films, in the context of their use on high-performance mercury cadmium telluride (MCT infrared detectors are reviewed. The methods of growth, the interface properties and the applications of both native and deposited passivant films have been discussed. Native films include anodic, chemical, photochemical, and plasma oxides as well as anodic sulphides and fluoro-oxides. Deposited films include ZnS, photo-CVD-grown SiO2, CDTe, and SiN/sub x/. The properties of all these passivant films on MCT have been summarized.

  14. Study of rectification at the metal-cadmium telluride contact

    International Nuclear Information System (INIS)

    The barrier heights at the contact between metals and N or P type cadmium telluride have been determined. Various surface treatments have been used for the semiconductor: lapping, polishing and etching in a bromine in methanol solution. Depending on these preparation differences of about 0.1 eV have been observed for the barrier height which in any case was no more than 0.9 - 1.0 eV. These results can not be explained by only considering the Schottky theory of rectification

  15. Removal of CdTe in acidic media by magnetic ion-exchange resin: a potential recycling methodology for cadmium telluride photovoltaic waste.

    Science.gov (United States)

    Zhang, Teng; Dong, Zebin; Qu, Fei; Ding, Fazhu; Peng, Xingyu; Wang, Hongyan; Gu, Hongwei

    2014-08-30

    Sulfonated magnetic microspheres (PSt-DVB-SNa MPs) have been successfully prepared as adsorbents via an aqueous suspension polymerization of styrene-divinylbenzene and a sulfonation reaction successively. The resulting adsorbents were confirmed by means of Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS) and vibrating sample magnetometer (VSM). The leaching process of CdTe was optimized, and the removal efficiency of Cd and Te from the leaching solution was investigated. The adsorbents could directly remove all cations of Cd and Te from a highly acidic leaching solution of CdTe. The adsorption process for Cd and Te reached equilibrium in a few minutes and this process highly depended on the dosage of adsorbents and the affinity of sulfonate groups with cations. Because of its good adsorption capacity in strong acidic media, high adsorbing rate, and efficient magnetic separation from the solution, PSt-DVB-SNa MPs is expected to be an ideal material for the recycling of CdTe photovoltaic waste. PMID:25128764

  16. Cadmium Telluride-Titanium Dioxide Nanocomposite for Photodegradation of Organic Substance.

    Science.gov (United States)

    Ontam, Areeporn; Khaorapapong, Nithima; Ogawa, Makoto

    2015-12-01

    Cadmium telluride-titanium dioxide nanocomposite was prepared by hydrothermal reaction of sol-gel derived titanium dioxide and organically modified cadmium telluride. The crystallinity of titanium dioxide in the nanocomposite was higher than that of pure titanium dioxide obtained by the reaction under the same temperature and pressure conditions, showing that cadmium telluride induced the crystallization of titanium dioxide. Diffuse reflectance spectrum of the nanocomposite showed the higher absorption efficiency in the UV-visible region due to band-gap excitation of titanium dioxide. The nanocomposite significantly showed the improvement of photocatalytic activity for 4-chlorophenol with UV light.

  17. Thin film cadmium telluride photovoltaic cells

    Energy Technology Data Exchange (ETDEWEB)

    Compaan, A.; Bohn, R. (Toledo Univ., OH (United States))

    1992-04-01

    This report describes research to develop to vacuum-based growth techniques for CdTe thin-film solar cells: (1) laser-driven physical vapor deposition (LDPVD) and (2) radio-frequency (rf) sputtering. The LDPVD process was successfully used to deposit thin films of CdS, CdTe, and CdCl{sub 2}, as well as related alloys and doped semiconductor materials. The laser-driven deposition process readily permits the use of several target materials in the same vacuum chamber and, thus, complete solar cell structures were fabricated on SnO{sub 2}-coated glass using LDPVD. The rf sputtering process for film growth became operational, and progress was made in implementing it. Time was also devoted to enhancing or implementing a variety of film characterization systems and device testing facilities. A new system for transient spectroscopy on the ablation plume provided important new information on the physical mechanisms of LDPVD. The measurements show that, e.g., Cd is predominantly in the neutral atomic state in the plume but with a fraction that is highly excited internally ({ge} 6 eV), and that the typical neutral Cd translational kinetic energies perpendicular to the target are 20 eV and greater. 19 refs.

  18. Megapixel mercury cadmium telluride focal plane arrays for infrared imaging out to 12 microns Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose the fabrication of large format, long wave infrared (LWIR) mercury cadmium telluride (HgCdTe or MCT) detector arrays where the cutoff wavelength is...

  19. High efficiency thin film cadmium telluride solar cells

    Science.gov (United States)

    Chu, T. L.; Chu, Shirley S.; Britt, J.; Chen, G.; Ferekides, C.; Schultz, N.; Wang, C.; Wu, C. Q.

    1992-12-01

    Cadmium sulfide (CdS), grown from an aqueous solution, and zinc oxide (ZnO), cadmium zinc sulfide (Cd1-xZnxS), and zinc selenide (ZnSe), deposited by metalorganic chemical vapor deposition (MOCVD), have been used as the window for thin film cadmium telluride (CdTe) solar cells. Thin film solar cells were prepared by the successive deposition of the window and p-CdTe (by MOCVD and close-spaced sublimation, CSS) on SnO2:F/glass substrates. CdS/CdTe(CSS) solar cells show considerably better characteristics than CdS/CdTe(MOCVD) solar cells because of the better microstructure of CSS CdTe films. Total area conversion efficiency of 14.6%, verified by the National Renewable Energy Laboratory, has been achieved for solar cells of about 1 cm2 area. Solar cell prepared by using ZnO, ZnSe, or Cd1-xZnxS as window have significantly lower photovoltage than CdS/CdTe solar cells.

  20. Optical properties of thermally evaporated cadmium telluride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Khairnar, U.P.; Bhavsar, D.S.; Vaidya, R.U.; Bhavsar, G.P

    2003-05-26

    Polycrystalline CdTe films have been deposited onto glass substrates at 373 K by vacuum evaporation technique. The transmittance and reflectance have been measured at normal and near normal incidence, respectively, in the spectral range 200-2500 nm. The dependence of absorption coefficient, {alpha} on the photon energy have been determined. Analysis of the result showed that for CdTe films of different thicknesses, direct transition occurs with band gap energies in the range 1.45-1.52 eV. Refractive indices and extinction coefficients have been evaluated in the above spectral range. The XRD analysis confirmed that CdTe films are polycrystalline having hexagonal structure. The lattice parameters of thin films are almost matching with the JCPDS 82-0474 data for cadmium telluride.

  1. Mercury Cadmium Telluride Photoconductive Long Wave Infrared Linear Array Detectors

    Directory of Open Access Journals (Sweden)

    Risal Singh

    2003-07-01

    Full Text Available Mercury cadmium telluride (Hg1-x, CdxTe (MCT photoconductive long wave infrared linear arrays are still in demand due to several advantages. The linear array technology is well established, easier, economical and is quite relevant to thermal imaging even today. The scan thermal imaging systems based on this technology offer wider field of view coverage and capacity for higher resolution in the scan direction relative to staring systems that use expensive and yet to mature focal plane array detector technology. A critical review on photoconductive n-Hg1-x CdxTe linear array detector technology for the long wave infrared range has been presented. The emphasis lies on detector design and processing technology. The critical issues of diffusion and drift effects, Hi-Lo and heterostructure blocking contacts, surface passivation, and other related aspects have been considered from the detector design angle. The device processing technology aspects are of vital importance

  2. Study on thermal annealing of cadmium zinc telluride (CZT) crystals

    Energy Technology Data Exchange (ETDEWEB)

    Yang, G.; Bolotnikov, A.E.; Fochuk, P.M.; Camarda, G.S.; Cui, Y.; Hossain, A.; Kim, K.; Horace, J.; McCall, B.; Gul, R.; Xu, L.; Kopach, O.V.; and James, R.B.

    2010-08-01

    Cadmium Zinc Telluride (CZT) has attracted increasing interest with its promising potential as a room-temperature nuclear-radiation-detector material. However, different defects in CZT crystals, especially Te inclusions and dislocations, can degrade the performance of CZT detectors. Post-growth annealing is a good approach potentially to eliminate the deleterious influence of these defects. At Brookhaven National Laboratory (BNL), we built up different facilities for investigating post-growth annealing of CZT. Here, we report our latest experimental results. Cd-vapor annealing reduces the density of Te inclusions, while large temperature gradient promotes the migration of small-size Te inclusions. Simultaneously, the annealing lowers the density of dislocations. However, only-Cd-vapor annealing decreases the resistivity, possibly reflecting the introduction of extra Cd in the lattice. Subsequent Te-vapor annealing is needed to ensure the recovery of the resistivity after removing the Te inclusions.

  3. Study of oxide films on the surface of cadmium telluride

    International Nuclear Information System (INIS)

    Study of oxide films on surfaces of CdTe monocrystals is continued by methods of ellipsometry and by absorption in IR-spectral range. Index values of refruction of oxide films, produced by cadmium telluride oxidation in hydrogen peroxide solutions, in oxigen flow at 673 K and by anode oxidation, as a rule, differ essentially in dependence on method of production, that gives evidence of differences in these films composition. Oxide films, produced in oxygen flow, as opposed to films, produced by two other methods, have intensive absorption, characteristic for tellurite group. Film thickness, produced by oxidation in hydrogen peroxide and in oxygen flow, varies within rather wide limits with observance of externally similar conditions of production. By contrast to it, thickness of anode films is regulated reliably by anode potential

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

    Science.gov (United States)

    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.

  5. Thin film cadmium telluride solar cells by two chemical vapor deposition techniques

    Energy Technology Data Exchange (ETDEWEB)

    Chu, T.L.

    1988-01-15

    Cadmium telluride (CdTe) has long been recognized as a promising thin film photovoltaic material. In this work, polycrystalline p-CdTe films have been deposited by two chemical vapor deposition techniques, namely the combination of vapors of elements (CVE) and close-spaced sublimation (CSS). The CVE technique is more flexible in controlling the composition of deposited films while the CSS technique can provide very high deposition rates. The resistivity of p-CdTe films deposited by the CVE and CSS techniques can be controlled by intrinsic (cadmium vacancies) or extrinsic (arsenic or antimony) doping, and the lowest resistivity obtainable is about 200 ..cap omega.. cm. Both front-wall (CdTe/TCS/glass) and back-wall (TCS/CdTe/substrate) cells have been prepared. The back-wall cells are less efficient because of the high and irreproducible p-CdTe-substrate interface resistance. The CSS technique is superior to the CVE technique because of its simplicity and high deposition rates; however, the cleaning of the substrate in situ is more difficult. The interface cleanliness is an important factor determining the electrical and photovoltaic characteristics of the heterojunction. Heterojunction CdS/CdTe solar cells of area 1 cm/sup 2/ with conversion efficiencies higher than 10% have been prepared and junction properties characterized.

  6. Varying cadmium telluride growth temperature during deposition to increase solar cell reliability

    Energy Technology Data Exchange (ETDEWEB)

    Albin, David S.; Johnson, James Neil; Zhao, Yu; Korevaar, Bastiaan Arie

    2016-04-26

    A method for forming thin films or layers of cadmium telluride (CdTe) for use in photovoltaic modules or solar cells. The method includes varying the substrate temperature during the growth of the CdTe layer by preheating a substrate (e.g., a substrate with a cadmium sulfide (CdS) heterojunction or layer) suspended over a CdTe source to remove moisture to a relatively low preheat temperature. Then, the method includes directly heating only the CdTe source, which in turn indirectly heats the substrate upon which the CdTe is deposited. The method improves the resulting CdTe solar cell reliability. The resulting microstructure exhibits a distinct grain size distribution such that the initial region is composed of smaller grains than the bulk region portion of the deposited CdTe. Resulting devices exhibit a behavior suggesting a more n-like CdTe material near the CdS heterojunction than devices grown with substrate temperatures held constant during CdTe deposition.

  7. Ambient temperature cadmium zinc telluride radiation detector and amplifier circuit

    International Nuclear Information System (INIS)

    A low noise, low power consumption, compact, ambient temperature signal amplifier for a Cadmium Zinc Telluride (CZT) radiation detector is disclosed. The amplifier can be used within a larger system (e.g., including a multi-channel analyzer) to allow isotopic analysis of radionuclides in the field. In one embodiment, the circuit stages of the low power, low noise amplifier are constructed using integrated circuit (IC) amplifiers , rather than discrete components, and include a very low noise, high gain, high bandwidth dual part preamplification stage, an amplification stage, and an filter stage. The low noise, low power consumption, compact, ambient temperature amplifier enables the CZT detector to achieve both the efficiency required to determine the presence of radionuclides and the resolution necessary to perform isotopic analysis to perform nuclear material identification. The present low noise, low power, compact, ambient temperature amplifier enables a CZT detector to achieve resolution of less than 3% full width at half maximum at 122 keV for a Cobalt-57 isotope source. By using IC circuits and using only a single 12 volt supply and ground, the novel amplifier provides significant power savings and is well suited for prolonged portable in-field use and does not require heavy, bulky power supply components. 9 figs

  8. Preliminary uranium enrichment analysis results using cadmium zinc telluride detectors

    International Nuclear Information System (INIS)

    Lawrence Livermore National Laboratory (LLNL) and EG ampersand G ORTEC have jointly developed a portable ambient-temperature detection system that can be used in a number of application scenarios. The detection system uses a planar cadmium zinc telluride (CZT) detector with custom-designed detector support electronics developed at LLNL and is based on the recently released MicroNOMAD multichannel analyzer (MCA) produced by ORTEC. Spectral analysis is performed using software developed at LLNL that was originally designed for use with high-purity germanium (HPGe) detector systems. In one application, the CZT detection system determines uranium enrichments ranging from less than 3% to over 75% to within accuracies of 20%. The analysis was performed using sample sizes of 200 g or larger and acquisition times of 30 min. The authors have demonstrated the capabilities of this system by analyzing the spectra gathered by the CZT detection system from uranium sources of several enrichments. These experiments demonstrate that current CZT detectors can, in some cases, approach performance criteria that were previously the exclusive domain of larger HPGe detector systems

  9. Using atomistic simulations to model cadmium telluride thin film growth

    Science.gov (United States)

    Yu, Miao; Kenny, Steven D.

    2016-03-01

    Cadmium telluride (CdTe) is an excellent material for low-cost, high efficiency thin film solar cells. It is important to conduct research on how defects are formed during the growth process, since defects lower the efficiency of solar cells. In this work we use computer simulation to predict the growth of a sputter deposited CdTe thin film. On-the-fly kinetic Monte Carlo technique is used to simulate the CdTe thin film growth on the (1 1 1) surfaces. The results show that on the (1 1 1) surfaces the growth mechanisms on surfaces which are terminated by Cd or Te are quite different, regardless of the deposition energy (0.1∼ 10 eV). On the Te-terminated (1 1 1) surface the deposited clusters first form a single mixed species layer, then the Te atoms in the mixed layer moved up to form a new layer. Whilst on the Cd-terminated (1 1 1) surface the new Cd and Te layers are formed at the same time. Such differences are probably caused by stronger bonding between ad-atoms and surface atoms on the Te layer than on the Cd layer.

  10. Health, safety and environmental issues relating to cadmium usage in photovoltaic energy systems

    Energy Technology Data Exchange (ETDEWEB)

    Moskowitz, P.D.; Fthenakis, V.M. (Brookhaven National Lab., Upton, NY (USA)); Zweibel, K. (Solar Energy Research Inst., Golden, CO (USA))

    1989-12-01

    This paper discusses the current technology base and hazards associated with two promising thin-film photovoltaic cells that contain cadmium compounds -- cadmium telluride (CdTe) and copper indium diselenide (CuInSe{sub 2}). More specifically, this paper summarizes the toxicological information on cadmium (Cd) compounds; evaluates potential health, safety and environmental hazards associated with cadmium usage in the photovoltaics industry; describes regulatory requirements associated with the use, handling and disposal of cadmium compounds; and lists management options to permit the safe and continued use of these materials. Handling of cadmium in photovoltaic production can present hazards to health, safety and the environment. Prior recognition of these hazards can allow device manufacturers and regulators to implement appropriate and readily available hazard management strategies. Hazards associated with product use (i.e., array fires) and disposal remain controversial and partially unresolved. The most likely effects that could be expected would be those associated with chronic low-level exposures to cadmium wastes. Because of the general immobility of the cadmium present in these devices and availability of environmental and biomonitoring protocols, chronic hazards can be monitored, and remediated if necessary. Nevertheless, concern about cadmium hazards should continue to be emphasized to ensure that health, safety and environmental issues are properly managed. At the same time, the potential role that these systems can play in ameliorating some important health and environmental hazards related to other energy systems should not be ignored. 27 refs., 5 figs., 2 tabs.

  11. X-ray computed tomography system utilizing a cadmium telluride detector

    OpenAIRE

    佐藤, 英一; 野宮, 聖一郎; 人見, 啓太朗; 尾鍋, 秀明; 河合, 敏明; 小川, 彰; 佐藤, 成大; 市丸, 俊夫; サトウ, エイイチ; ノミヤ, セイイチロウ; ヒトミ, ケイタロウ; オナベ, ヒデアキ; カワイ, トシアキ; オガワ, アキラ; サトウ, シゲヒロ

    2007-01-01

    A simple x-ray computed tomography(CT) system utilizing a cadmium telluride detector is described. The CT system is of the first generation type and consists of an x-ray generator, a turn table, a translation table, a motor drive unit, a cadmium telluride detector, an interface unit for the detector, and a personal computer(PC). Tomography was performed by the repetition of the translation and rotation of an object. The maximum values of the tube voltage and the tube current were 110kV and 2....

  12. Current transport mechanisms in mercury cadmium telluride diode

    Science.gov (United States)

    Gopal, Vishnu; Li, Qing; He, Jiale; He, Kai; Lin, Chun; Hu, Weida

    2016-08-01

    This paper reports the results of modelling of the current-voltage characteristics (I-V) of a planar mid-wave Mercury Cadmium Telluride photodiode in a gate controlled diode experiment. It is reported that the diode exhibits nearly ideal I-V characteristics under the optimum surface potential leading to the minimal surface leakage current. Deviations from the optimum surface potential lead to non ideal I-V characteristics, indicating a strong relationship between the ideality factor of the diode with its surface leakage current. Diode's I-V characteristics have been modelled over a range of gate voltages from -9 V to -2 V. This range of gate voltages includes accumulation, flat band, and depletion and inversion conditions below the gate structure of the diode. It is shown that the I-V characteristics of the diode can be very well described by (i) thermal diffusion current, (ii) ohmic shunt current, (iii) photo-current due to background illumination, and (iv) excess current that grows by the process of avalanche multiplication in the gate voltage range from -3 V to -5 V that corresponds to the optimum surface potential. Outside the optimum gate voltage range, the origin of the excess current of the diode is associated with its high surface leakage currents. It is reported that the ohmic shunt current model applies to small surface leakage currents. The higher surface leakage currents exhibit a nonlinear shunt behaviour. It is also shown that the observed zero-bias dynamic resistance of the diode over the entire gate voltage range is the sum of ohmic shunt resistance and estimated zero-bias dynamic resistance of the diode from its thermal saturation current.

  13. Directional Solidification of Mercury Cadmium Telluride in Microgravity

    Science.gov (United States)

    Lechoczhy, Sandor L.; Gillies, Donald C.; Szofran, Frank R.; Watring, Dale A.

    1998-01-01

    Mercury cadmium telluride (MCT) has been directionally solidified for ten days in the Advanced Automated Directional Solidification Furnace (AADSF) on the second United States Microgravity Payload Mission (USMP-2). A second growth experiment is planned for the USMP-4 mission in November 1997. Results from USMP-2 demonstrated significant changes between microgravity and ground-based experiments, particularly in the compositional homogeneity. Changes were also observed during the microgravity mission which were dependent on the attitude of the space shuttle and the relative magnitudes of axial and transverse residual accelerations with respect to the growth axis of the crystal. Issues of shuttle operation, especially those concerned with safety and navigation, and the science needs of other payloads dictated the need for changes in attitude. One consequence for solidification of MCT in the USMP4 mission is the desire for a shorter growth time to complete the experiment without subjecting the sample to shuttle maneuvers. By using a seeded technique and a pre-processed boule of MCT with an established diffusion layer quenched into the solid, equilibrium steady state growth can be established within 24 hours, rather than the three days needed in USMP-2. The growth of MCT in AADSF during the USMP-4 mission has been planned to take less than 72 hours with 48 hours of actual growth time. A review of the USMP-2 results will be presented, and the rationale for the USMP-4 explained. Pre-mission ground based tests for the USN4P-4 mission will be presented, as will any available preliminary flight results from the mission.

  14. Health, safety and environmental issues relating to cadmium usage in photovoltaic energy systems

    Energy Technology Data Exchange (ETDEWEB)

    Moskowitz, P.D.; Fthenakis, V.M. (Brookhaven National Lab., Upton, NY (USA)); Zweibel, K. (Solar Energy Research Inst., Golden, CO (USA))

    1990-01-01

    This paper discusses the current technology base and hazards associated with two promising thin-film photovoltaic cells that contain cadmium compounds--cadmium telluride (CdTe) and copper indium deselenide (CuInSe{sub 2}). More specifically, this paper summarized the toxicological information on cadmium (Cd) compounds;evaluates potential health, safety and environmental hazards associated with cadmium usage in the photovoltaics industry; describes regulatory requirements associated with the use, handling and disposal of cadmium compounds; and lists management options to permit the safe and continued use of these materials. Handling of cadmium in photovoltaic production can present hazards to health, safety and the environment. Prior recognition of these hazards can allow device manufacturers and regulators to implement appropriate and readily available hazard management strategies. Hazards associated with product use (i.e., array fires) and disposal remain controversial and partially unresolved. The most likely effects that could be expected would be those associated with chronic low-level exposures to cadmium wastes. Because of the general immobility of the cadmium present in these devices and availability of environmental and biomonitoring protocols, chronic hazards can be monitored, and remediated if necessary. 26 refs., 5 figs., 2 tabs.

  15. Stable, high efficiency thin film solar cells produced by electrodeposition of cadmium telluride

    Energy Technology Data Exchange (ETDEWEB)

    Turner, A.K.; Woodcock, J.M.; Ozsan, M.E.; Summers, J.G.; Barker, J.; Binns, S.; Buchanan, K.; Chai, C.; Dennison, S.; Hart, R.; Johnson, D.; Marshall, R.; Oktik, S.; Patterson, M.; Perks, R.; Roberts, S.; Sadeghi, M.; Sherborne, J.; Szubert, J.; Webster, S. (BP Solar, Solar House, Leatherhead (United Kingdom))

    1991-12-01

    The highest known efficiency of 9.5% for a 300x300 mm series interconnected cadmium telluride solar cell is reported. In addition, efficiencies of up to 13% have been measured for small cells based on electrodeposited CdTe. The stability of modules in outdoor tests is discussed and an outline is given of the device fabrication procedure. (orig.).

  16. Thin-film cadmium telluride solar cells: Final subcontract report, 1 May 1985--31 May 1988

    Energy Technology Data Exchange (ETDEWEB)

    Chu, T.L.

    1988-06-01

    This report describes results of research performed to demonstrate thin-film cadmium telluride heterojunction solar cells with a total area greater than 1 cm/sup 2/ and efficiencies of 13% or higher. Efforts were directed to (1) the deposition, resistivity control, and characterization of p-CdTe films by combining the vapor of the elements (CVE) and close-spaced sublimation (CSS) techniques; (2) the deposition and characterization of transparent conducting semiconductors; (3) the deposition of p-HgTe as a low-resistance ohmic contact to p-CdTe; (4) the electrical properties of CdS/CdTe heterojunctions; and (5) the preparation and evaluation of heterojunction solar cells. CdS/CdTe solar cells showed the best photovoltaic characteristics, and the best cell had a conversion efficiency of about 10.6%. 20 refs., 30 figs., 1 tab.

  17. Characterization of large cadmium zinc telluride crystals grown by traveling heater method

    DEFF Research Database (Denmark)

    Chen, H.; Awadalla, S.A.; Iniewski, K.;

    2008-01-01

    The focus of this paper is to evaluate thick, 20 X 20 X 10 and 10 X 10 X 10 mm(3), cadmium zinc telluride (CZT), Cd0.9Zn0.1Te, crystals grown using the traveling heater method (THIM). The phenomenal spectral performance and small size and low concentration of Te inclusions/precipitates of these c......The focus of this paper is to evaluate thick, 20 X 20 X 10 and 10 X 10 X 10 mm(3), cadmium zinc telluride (CZT), Cd0.9Zn0.1Te, crystals grown using the traveling heater method (THIM). The phenomenal spectral performance and small size and low concentration of Te inclusions...

  18. Optical property of amorphous semiconductor mercury cadmium telluride from first-principles study

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The structural and optical properties of amorphous semiconductor mercury cadmium telluride (a-MCT) are obtained by the first principles calculations. The total pair distribution functions and the density of states show that the a-MCT has the semiconductor characteristic. The calculated results of dielectric function show that E2 peak of the imaginary of dielectric function for the crystal mercury cadmium telluride abruptly disappears in the amorphous case due to the long-range disorders. And the imaginary of dielectric function of a-MCT shows a large broad peak, which is in agreement with the available results of other amorphous semiconductors. From the linear extrapolation of the curve ωε 2(ω)1/2 versus ω, it can be obtained that the optical energy gap of amorphous semiconductor Hg0.5Cd0.5Te is 0.51±0.05 eV.

  19. Optical property of amorphous semiconductor mercury cadmium telluride from first-principles study

    Institute of Scientific and Technical Information of China (English)

    WANG Liang; CHEN XiaoShuang; LU Wei; HUANG Yan; WANG XiaoFang; ZHAO JiJun

    2009-01-01

    The structural and optical properties of amorphous semiconductor mercury cadmium telluride(a-MCT) are obtained by the first principles calculations. The total pair distribution functions and the density of states show that the a-MCT has the semiconductor characteristic. The calculated results of dielectric function show that E2 peak of the imaginary of dielectric function for the crystal mercury cadmium telluride abruptly disappears in the amorphous case due to the long-range disorders. And the imaginary of dielectric function of a-MCT shows a large broad peak, which is in agreement with the available results of other amorphous semiconductors. From the linear extrapolation of the curve (n)ωε2(ω)1/2 versus (n)ω,it can be obtained that the optical energy gap of amorphous semiconductor Hg0.5Cd0.5Te is 0.51±0.05 eV.

  20. Spectroscopic, microscopic, and internal stress analysis in cadmium telluride grown by close-space sublimation

    Energy Technology Data Exchange (ETDEWEB)

    Manciu, Felicia S., E-mail: fsmanciu@utep.edu [Department of Physics, The University of Texas at El Paso, El Paso, TX 79968 (United States); Salazar, Jessica G. [Department of Physics, The University of Texas at El Paso, El Paso, TX 79968 (United States); Diaz, Aryzbe; Quinones, Stella A. [Department of Electrical and Computer Engineering, The University of Texas at El Paso, El Paso, TX 79968 (United States)

    2015-08-31

    High quality materials with excellent ordered structure are needed for developing photovoltaic and infrared devices. With this end in mind, the results of our research prove the importance of a detailed, comprehensive spectroscopic and microscopic analysis in assessing cadmium telluride (CdTe) characteristics. The goal of this work is to examine not only material crystallinity and morphology, but also induced stress in the deposit material. A uniform, selective growth of polycrystalline CdTe by close-space sublimation on patterned Si(111) and Si(211) substrates is demonstrated by scanning electron microscopy images. Besides good crystallinity of the samples, as revealed by both Raman scattering and Fourier transform infrared absorption investigations, the far-infrared transmission data also show the presence of surface optical phonon modes, which is direct evidence of confinement in such a material. The qualitative identification of the induced stress was achieved by performing confocal Raman mapping microscopy on sample surfaces and by monitoring the existence of the rock-salt and zinc-blende structural phases of CdTe, which were associated with strained and unstrained morphologies, respectively. Although the induced stress in the material is still largely due to the high lattice mismatch between CdTe and the Si substrate, the current results provide a direct visualization of its partial release through the relaxation effect at crystallite boundaries and of preferential growth directions of less strain. Our study, thus offers significant value for improvement of material properties, by targeting the needed adjustments in the growth processes. - Highlights: • Assessing the characteristics of CdTe deposited on patterned Si substrates • Proving the utility of confocal Raman microscopy in monitoring the induced stress • Confirming the partial stress release through the grain boundary relaxation effect • Demonstrating the phonon confinement effect in low

  1. Mitochondrial Toxicity of Cadmium Telluride Quantum Dot Nanoparticles in Mammalian Hepatocytes

    OpenAIRE

    Nguyen, Kathy C; Rippstein, Peter; Tayabali, Azam F.; Willmore, William G.

    2015-01-01

    There are an increasing number of studies indicating that mitochondria are relevant targets in nanomaterial-induced toxicity. However, the underlying mechanisms by which nanoparticles (NPs) interact with these organelles and affect their functions are unknown. The aim of this study was to investigate the effects of cadmium telluride quantum dot (CdTe-QD) NPs on mitochondria in human hepatocellular carcinoma HepG2 cells. CdTe-QD treatment resulted in the enlargement of mitochondria as examined...

  2. Recycling of cadmium and selenium from photovoltaic modules and manufacturing wastes. A workshop report

    Energy Technology Data Exchange (ETDEWEB)

    Moskowitz, P.D.; Zweibel, K. [eds.

    1992-10-01

    Since the development of the first silicon based photovoltaic cell in the 1950`s, large advances have been made in photovoltaic material and processing options. At present there is growing interest in the commercial potential of cadmium telluride (CdTe) and copper indium diselenide (CIS) photovoltaic modules. As the commercial potential of these technologies becomes more apparent, interest in the environmental, health and safety issues associated with their production, use and disposal has also increased because of the continuing regulatory focus on cadmium and selenium. In future, recycling of spent or broken CdTe and CIS modules and manufacturing wastes may be needed for environmental, economic or political reasons. To assist industry to identify recycling options early in the commercialization process, a Workshop was convened. At this Workshop, representatives from the photovoltaic, electric utility, and nonferrous metals industries met to explore technical and institutional options for the recycling of spent CdTe and CIS modules and manufacturing wastes. This report summarizes the results of the Workshop. This report includes: (1) A discussion of the Resource Conservation and Recovery Act regulations and their potential implications to the photovoltaic industry; (2) an assessment of the needs of the photovoltaic industry from the perspective of module manufacturers and consumers; (3) an overview of recycling technologies now employed by other industries for similar types of materials; and, (4) a list of recommendation.

  3. Spatial mapping of cadmium zinc telluride materials properties and electrical response to improve device yield and performance

    CERN Document Server

    Van Scyoc, J M; Yoon, H; Gilbert, T S; Hilton, N R; Lund, J C; James, R B

    1999-01-01

    Cadmium zinc telluride has experienced tremendous growth in its application to various radiation sensing problems over the last five years. However, there are still issues with yield, particularly of the large volume devices needed for imaging and sensitivity-critical applications. Inhomogeneities of various types and on various length scales currently prevent the fabrication of large devices of high spectral performance. This paper discusses the development of a set of characterization tools for quantifying these inhomogeneities, in order to develop improvement strategies to achieve the desired cadmium zinc telluride crystals for detector fabrication.

  4. Specific features of the photoconductivity of semi-insulating cadmium telluride

    Energy Technology Data Exchange (ETDEWEB)

    Golubyatnikov, V. A.; Grigor’ev, F. I.; Lysenko, A. P., E-mail: aplysenko@hse.ru; Strogankova, N. I.; Shadov, M. B. [National Research University Higher School of Economics, Moscow Institute of Electronics and Mathematics (Russian Federation); Belov, A. G. [OAO GIREDMET State Research and Design Institute of the Rare-Metal Industry (Russian Federation)

    2014-12-15

    The effect of local illumination providing a high level of free-carrier injection on the conductivity of a sample of semi-insulating cadmium telluride and on the properties of ohmic contacts to the sample is studied. It is found that, irrespective of the illumination region, the contact resistance of ohmic contacts decreases and the concentration of majority carriers in the sample grows in proportion to the illumination intensity. It is shown that inherent heterogeneities in crystals of semi-insulating semiconductors can be studied by scanning with a light probe.

  5. Synthesis of cadmium telluride quantum wires and the similarity of their band gaps to those of equidiameter cadmium telluride quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lin-Wang; Sun, Jianwei; Wang, Lin-Wang; Buhro, William E.

    2008-07-11

    High-quality colloidal CdTe quantum wires having purposefully controlled diameters in the range of 5-11 nm are grown by the solution-liquid-solid (SLS) method, using Bi-nanoparticle catalysts, cadmium octadecylphosphonate and trioctylphosphine telluride as precursors, and a TOPO solvent. The wires adopt the wurtzite structure, and grow along the [002] direction (parallel to the c axis). The size dependence of the band gaps in the wires are determined from the absorption spectra, and compared to the experimental results for high-quality CdTe quantum dots. In contrast to the predictions of an effective-mass approximation, particle-in-a-box model, and previous experimental results from CdSe and InP dot-wire comparisons, the band gaps of CdTe dots and wires of like diameter are found to be experimentally indistinguishable. The present results are analyzed using density functional theory under the local-density approximation by implementing a charge-patching method. The higher-level theoretical analysis finds the general existence of a threshold diameter, above which dot and wire band gaps converge. The origin and magnitude of this threshold diameter is discussed.

  6. Controlled cadmium telluride thin films for solar cell applications (emerging materials systems for solar cell applications). Quarterly progress report No. 1, April 9-July 8, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Vedam, K.

    1979-08-01

    Preparation and properties of cadmium telluride thin films for use in solar cells are studied. CdTe sputter deposition, crystal doping, and carrier typing are discussed. Future experimental plans are described. (WHK)

  7. The use of cadmium telluride detectors for the qualitative analysis of diagnostic x-ray spectra.

    Science.gov (United States)

    Di Castro, E; Pani, R; Pellegrini, R; Bacci, C

    1984-09-01

    A method is introduced for the evaluation of x-ray spectra from x-ray machines operating in the range 50-100 kVp using a cadmium telluride (CdTe) detector with low detection efficiency. The pulse height distribution obtained with this kind of detector does not represent the true photon spectra owing to the presence of K-escape, Compton scattering, etc.; these effects were evaluated using a Monte Carlo method. A stripping procedure is described for implementation on a Univac 1100/82 computer. The validity of our method was finally tested by comparison with experimental results obtained with a Ge detector and with data from the literature; the results are in good agreement with published data. PMID:6483976

  8. Ion Beam Induced Charge Collection (IBICC) Studies of Cadmium Zinc Telluride (CZT) Radiation Detectors

    International Nuclear Information System (INIS)

    Cadmium Zinc Telluride is an emerging material for room temperature radiation detectors. In order to optimize the performance of these detectors, it is important to determine how the electronic properties of CZT are related to the presence of impurities and defects that are introduced during the crystal growth and detector fabrication. At the Sandia microbeam facility IBICC and Time Resolved IBICC (TRIBICC) were used to image electronic properties of various CZT detectors. Two-dimensional areal maps of charge collection efficiency were deduced from the measurements. In order to determine radiation damage to the detectors, we measured the deterioration of the IBICC signal as the function of dose. A model to explain quantitatively the pattern observed in the charge collection efficiency maps of the damaged detectors has been developed and will be discussed in the paper

  9. Electronic properties of chlorine doped cadmium telluride used as high energy photoconductive detector

    International Nuclear Information System (INIS)

    A new high energy X-ray chlorine doped Cadmium Telluride (CdTe:Cl) photoconductor is described. We discuss different deposition techniques (Sputtering, Evaporation, Electroless) to realize ohmic contacts which have low leakage current and which allow high applied electric field. The temperature dependence of the dark current give an activation energy of 0.6 eV for standard CdTe:Cl. The transient response of photoconductors under high X-ray energy beams has been characterized using three different pulse duration 150 ps, 30 ns and 4 μs. Sensitivity and speed of response are studied as a function of neutron pre-irradiated doses (0, 1014, 1015, 1016 n/cm2): neutron irradiations reduce the carrier lifetime at the expense of a lower sensitivity

  10. Internal Electric Field Behavior of Cadmium Zinc Telluride Radiation Detectors Under High Carrier Injection

    Energy Technology Data Exchange (ETDEWEB)

    Yang, G.; Bolotnikov, A.E.; Camarda, G.S.; Cui, Y.; Hossain, A.; Kim, K.H.; Gul, R.; and James, R.B.

    2010-10-26

    The behavior of the internal electric-field of nuclear-radiation detectors substantially affects the detector's performance. We investigated the distribution of the internal field in cadmium zinc telluride (CZT) detectors under high carrier injection. We noted the build-up of a space charge region near the cathode that produces a built-in field opposing the applied field. Its presence entails the collapse of the electric field in the rest of detector, other than the portion near the cathode. Such a space-charge region originates from serious hole-trapping in CZT. The device's operating temperature greatly affects the width of the space-charge region. With increasing temperature from 5 C to 35 C, its width expanded from about 1/6 to 1/2 of the total depth of the detector.

  11. An optically-interrogated microwave-Poynting-vector sensor using cadmium manganese telluride.

    Science.gov (United States)

    Chen, Chia-Chu; Whitaker, John F

    2010-06-01

    A single cadmium-manganese-telluride crystal that exhibits both the Pockels and Faraday effects is used to produce a Poynting-vector sensor for signals in the microwave regime. This multi-birefringent crystal can independently measure either electric or magnetic fields through control of the polarization of the optical probe beam. After obtaining all the relevant electric and magnetic field components, a map of the Poynting vector along a 50-Omega microstrip was experimentally determined without the need for any further transformational calculations. The results demonstrate that this sensor can be used for near-field mapping of the Poynting vector. Utilizing both amplitude and phase information from the fields in the microwave signal, it was confirmed for the case of an open-terminated microstrip that no energy flowed to the load, while for a microstrip with a matched termination, the energy flowed consistently along the transmission line. PMID:20588348

  12. Cadmium telluride quantum dots as pH-sensitive probes for tiopronin determination

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yunqing; Ye Chao; Zhu Zhenghui [Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, Nanjing 210009 (China); Department of Analytical Chemistry, China Pharmaceutical University, Nanjing 210009 (China); Hu Yuzhu [Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, Nanjing 210009 (China) and Department of Analytical Chemistry, China Pharmaceutical University, Nanjing 210009 (China)], E-mail: njhuyuzu@126.com

    2008-03-03

    The pH-sensitive cadmium telluride (CdTe) quantum dots (QDs) were used as proton probes for tiopronin determination. Based on the fluorescence quenching of CdTe QDs caused by tiopronin, a simple, rapid and specific quantitative method was proposed. Under the optimal conditions, the calibration plot of ln(F{sub 0}/F) with concentration of tiopronin was linear in the range of 0.15-20 {mu}g mL{sup -1}(0.92-122.5 {mu}mol L{sup -1}) with correlation coefficient of 0.998. The limit of detection (LOD) (3{sigma}/k) was 0.15 {mu}g mL{sup -1}(0.92 {mu}mol mL{sup -1}). The content of tiopronin in pharmaceutical tablet was determined by the proposed method and the result agreed with that obtained from the oxidation-reduction titration method and the claimed value.

  13. Cadmium telluride quantum dots as pH-sensitive probes for tiopronin determination

    International Nuclear Information System (INIS)

    The pH-sensitive cadmium telluride (CdTe) quantum dots (QDs) were used as proton probes for tiopronin determination. Based on the fluorescence quenching of CdTe QDs caused by tiopronin, a simple, rapid and specific quantitative method was proposed. Under the optimal conditions, the calibration plot of ln(F0/F) with concentration of tiopronin was linear in the range of 0.15-20 μg mL-1(0.92-122.5 μmol L-1) with correlation coefficient of 0.998. The limit of detection (LOD) (3σ/k) was 0.15 μg mL-1(0.92 μmol mL-1). The content of tiopronin in pharmaceutical tablet was determined by the proposed method and the result agreed with that obtained from the oxidation-reduction titration method and the claimed value

  14. Experiments and Monte Carlo modeling of a higher resolution Cadmium Zinc Telluride detector for safeguards applications

    Science.gov (United States)

    Borella, Alessandro

    2016-09-01

    The Belgian Nuclear Research Centre is engaged in R&D activity in the field of Non Destructive Analysis on nuclear materials, with focus on spent fuel characterization. A 500 mm3 Cadmium Zinc Telluride (CZT) with enhanced resolution was recently purchased. With a full width at half maximum of 1.3% at 662 keV, the detector is very promising in view of its use for applications such as determination of uranium enrichment and plutonium isotopic composition, as well as measurement on spent fuel. In this paper, I report about the work done with such a detector in terms of its characterization. The detector energy calibration, peak shape and efficiency were determined from experimental data. The data included measurements with calibrated sources, both in a bare and in a shielded environment. In addition, Monte Carlo calculations with the MCNPX code were carried out and benchmarked with experiments.

  15. Low-cost cadmium zinc telluride radiation detectors based on electron-transport-only designs

    International Nuclear Information System (INIS)

    The goal of this project was to utilize a novel device design to build a compact, high resolution, room temperature operated semiconductor gamma ray sensor. This sensor was constructed from a cadmium zinc telluride (CZT) crystal. It was able to both detect total radiation intensity and perform spectroscopy on the detected radiation. CZT detectors produced today have excellent electron charge carrier collection, but suffer from poor hole collection. For conventional gamma-ray spectrometers, both the electrons and holes must be collected with high efficiency to preserve energy resolution. The requirement to collect the hole carriers, which have relatively low lifetimes, limits the efficiency and performance of existing experimental devices. By implementing novel device designs such that the devices rely only on the electron signal for energy information, the sensitivity of the sensors for detecting radiation can be increased substantially. In this report the authors describe a project to develop a new type of electron-only CZT detector. They report on their successful efforts to design, implement and test these new radiation detectors. In addition to the design and construction of the sensors the authors also report, in considerable detail, on the electrical characteristics of the CZT crystals used to make their detectors

  16. Novel Cadmium Zinc Telluride Devices for Myocardial Perfusion Imaging-Technological Aspects and Clinical Applications.

    Science.gov (United States)

    Ben-Haim, Simona; Kennedy, John; Keidar, Zohar

    2016-07-01

    Myocardial perfusion imaging plays an important role in the assessment of patients with known or suspected coronary artery disease and is well established for diagnosis and for prognostic evaluation in these patients. The dedicated cardiac SPECT cameras with solid-state cadmium zinc telluride (CZT) detectors were first introduced a decade ago. A large body of evidence is building up, showing the superiority of the new technology compared with conventional gamma cameras. Not only the CZT detectors, but also new collimator geometries, the ability to perform focused imaging optimized for the heart and advances in data processing algorithms all contribute to the significantly improved sensitivity up to 8-10 times, as well as improved energy resolution and improved reconstructed spatial resolution compared with conventional technology. In this article, we provide an overview of the physical characteristics of the CZT cameras, as well as a review of the literature published so far, including validation studies in comparison with conventional myocardial perfusion imaging and with invasive coronary angiography, significant reduction in radiation dose, and new imaging protocols enabled by the new technology.

  17. Low-cost cadmium zinc telluride radiation detectors based on electron-transport-only designs

    Energy Technology Data Exchange (ETDEWEB)

    B. A. Brunett; J. C. Lund; J. M. Van Scyoc; N. R. Hilton; E. Y. Lee; R. B. James

    1999-01-01

    The goal of this project was to utilize a novel device design to build a compact, high resolution, room temperature operated semiconductor gamma ray sensor. This sensor was constructed from a cadmium zinc telluride (CZT) crystal. It was able to both detect total radiation intensity and perform spectroscopy on the detected radiation. CZT detectors produced today have excellent electron charge carrier collection, but suffer from poor hole collection. For conventional gamma-ray spectrometers, both the electrons and holes must be collected with high efficiency to preserve energy resolution. The requirement to collect the hole carriers, which have relatively low lifetimes, limits the efficiency and performance of existing experimental devices. By implementing novel device designs such that the devices rely only on the electron signal for energy information, the sensitivity of the sensors for detecting radiation can be increased substantially. In this report the authors describe a project to develop a new type of electron-only CZT detector. They report on their successful efforts to design, implement and test these new radiation detectors. In addition to the design and construction of the sensors the authors also report, in considerable detail, on the electrical characteristics of the CZT crystals used to make their detectors.

  18. Directional Solidification of Mercury Cadmium Telluride During the Second United States Microgravity Payload Mission (USMP-2)

    Science.gov (United States)

    Gillies, D. C.; Lehoczky, S. L.; Szofran, F. R.; Watring, D. A.; Alexander, H. A.; Jerman, G. A.

    1996-01-01

    As a solid solution semiconductor having, a large separation between liquidus and solidus, mercury cadmium telluride (MCT) presents a formidable challenge to crystal growers desiring an alloy of high compositional uniformity. To avoid constitutional supercooling during Bridgman crystal growth it is necessary to solidify slowly in a high temperature gradient region. The necessary translation rate of less than 1 mm/hr results in a situation where fluid flow induced by gravity on earth is a significant factor in material transport. The Advanced Automated Directional Solidification Furnace (AADSF) is equipped to provide the stable thermal environment with a high gradient, and the required slow translation rate needed. Ground based experiments in AADSF show clearly the dominance of flow driven transport. The first flight of AADSF in low gravity on USMP-2 provided an opportunity to test theories of fluid flow in MCT and showed several solidification regimes which are very different from those observed on earth. Residual acceleration vectors in the orbiter during the mission were measured by the Orbital Acceleration Research Experiment (OARE), and correlated well with observed compositional differences in the samples.

  19. Heart imaging by cadmium telluride gamma camera European Program 'BIOMED' consortium

    CERN Document Server

    Scheiber, C; Chambron, J; Prat, V; Kazandjan, A; Jahnke, A; Matz, R; Thomas, S; Warren, S; Hage-Hali, M; Regal, R; Siffert, P; Karman, M

    1999-01-01

    Cadmium telluride semiconductor detectors (CdTe) operating at room temperature are attractive for medical imaging because of their good energy resolution providing excellent spatial and contrast resolution. The compactness of the detection system allows the building of small light camera heads which can be used for bedside imaging. A mobile pixellated gamma camera based on 2304 CdTe (pixel size: 3x3 mm, field of view: 15 cmx15 cm) has been designed for cardiac imaging. A dedicated 16-channel integrated circuit has also been designed. The acquisition hardware is fully programmable (DSP card, personal computer-based system). Analytical calculations have shown that a commercial parallel hole collimator will fit the efficiency/resolution requirements for cardiac applications. Monte-Carlo simulations predict that the Moire effect can be reduced by a 15 deg. tilt of the collimator with respect to the detector grid. A 16x16 CdTe module has been built for the preliminary physical tests. The energy resolution was 6.16...

  20. Heart imaging by cadmium telluride gamma cameraEuropean Program ``BIOMED'' consortium

    Science.gov (United States)

    Scheiber, Ch.; Eclancher, B.; Chambron, J.; Prat, V.; Kazandjan, A.; Jahnke, A.; Matz, R.; Thomas, S.; Warren, S.; Hage-Hali, M.; Regal, R.; Siffert, P.; Karman, M.

    1999-06-01

    Cadmium telluride semiconductor detectors (CdTe) operating at room temperature are attractive for medical imaging because of their good energy resolution providing excellent spatial and contrast resolution. The compactness of the detection system allows the building of small light camera heads which can be used for bedside imaging. A mobile pixellated gamma camera based on 2304 CdTe (pixel size: 3×3 mm, field of view: 15 cm×15 cm) has been designed for cardiac imaging. A dedicated 16-channel integrated circuit has also been designed. The acquisition hardware is fully programmable (DSP card, personal computer-based system). Analytical calculations have shown that a commercial parrallel hole collimator will fit the efficiency/resolution requirements for cardiac applications. Monte-Carlo simulations predict that the Moire effect can be reduced by a 15° tilt of the collimator with respect to the detector grid. A 16×16 CdTe module has been built for the preliminary physical tests. The energy resolution was 6.16±0.6 keV (mean ± standard deviation, n=30). Uniformity was ±10%, improving to ±1% when using a correction table. Test objects (emission data: letters 1.8 mm in width) and cold rods in scatter medium have been acquired. The CdTe images have been compared to those acquired with a conventionnal gamma camera.

  1. Investigation of the Electronic Properties of Cadmium Zinc Telluride (CZT) Detectors using a Nuclear Microprobe

    International Nuclear Information System (INIS)

    The electronic transport properties of Cadmium Zinc Telluride (CZT) determine the charge collection efficiency (i.e. the signal quality) of CZT detectors. These properties vary on both macroscopic and microscopic scale and depend on the presence of impurities and defects introduced during the crystal growth. Ion Beam Induced Charge Collection (IBICC) is a proven method to measure the charge collection efficiency. Using an ion microbeam, the charge collection efficiency can be mapped with submicron resolution, and the map of electronic properties (such as drift length) can be calculated from the measurement. A more sophisticated version of IBICC, the Time Resolved IBICC (TRIBICC) allows them to determine the mobility and the life time of the charge carriers by recording and analyzing the transient waveform of the detector signal. Furthermore, lateral IBICC and TRIBICC can provide information how the charge collection efficiency depends on the depth where the charge carriers are generated. This allows one to deduce information on the distribution of the electric field and transport properties of the charge carriers along the detector axis. IBICC and TRIBICC were used at the Sandia microbeam facility to image electronic properties of several CZT detectors. From the lateral TRIBICC measurement the electron and hole drift length profiles were calculated

  2. Inhibition of autophagy contributes to the toxicity of cadmium telluride quantum dots in Saccharomyces cerevisiae.

    Science.gov (United States)

    Fan, Junpeng; Shao, Ming; Lai, Lu; Liu, Yi; Xie, Zhixiong

    2016-01-01

    Cadmium telluride quantum dots (CdTe QDs) are used as near-infrared probes in biologic and medical applications, but their cytological effects and mechanism of potential toxicity are still unclear. In this study, we evaluated the toxicity of CdTe QDs of different sizes and investigated their mechanism of toxicity in the yeast Saccharomyces cerevisiae. A growth inhibition assay revealed that orange-emitting CdTe (O-CdTe) QDs (half inhibitory concentration [IC50] =59.44±12.02 nmol/L) were more toxic than green-emitting CdTe QDs (IC50 =186.61±19.74 nmol/L) to S. cerevisiae. Further studies on toxicity mechanisms using a transmission electron microscope and green fluorescent protein tagged Atg8 processing assay revealed that O-CdTe QDs could partially inhibit autophagy at a late stage, which differs from the results reported in mammalian cells. Moreover, autophagy inhibited at a late stage by O-CdTe QDs could be partially recovered by enhancing autophagy with rapamycin (an autophagy activator), combined with an increased number of living cells. These results indicate that inhibition of autophagy acts as a toxicity mechanism of CdTe QDs in S. cerevisiae. This work reports a novel toxicity mechanism of CdTe QDs in yeast and provides valuable information on the effect of CdTe QDs on the processes of living cells. PMID:27524895

  3. Investigation of the electrochemical deposition of thick layers of cadmium telluride

    International Nuclear Information System (INIS)

    This research thesis deals with the problem of electrochemical deposition of thick layers of cadmium telluride (CdTe) meeting the requirements of high energy radiation detection. The author first recalls the physicochemical properties of CdTe and the basic principles of radiology. He details the different criteria which define a material for X ray detection. He describes the experimental conditions, the nature and preparation of substrates, and the different electrochemical systems used in this research. He studies the impact of the applied potential on the material properties, and compares previously obtained results available in the literature with those obtained in the chosen pool conditions. He discusses the synthesis of CdTe thick layers for which different methods are tested: static in potential, static in intensity, pulsed. The coatings obtained with a given potential and then with a given current are investigated. Finally, the influence of a thermal treatment in presence or absence of a sintering agent on the morphology, the chemical composition, and the crystalline and electric properties of the deposited material is discussed, and the results of the behaviour under X rays of a electrodeposited layer are presented

  4. 3D Particle Track Reconstrution in a Single Layer Cadmium-Telluride Hybrid Active Pixel Detector

    CERN Document Server

    Filipenko, Mykhaylo; Anton, Gisela; Michel, Thilo

    2014-01-01

    In the past 20 years the search for neutrinoless double beta decay has driven many developements in all kind of detector technology. A new branch in this field are highly-pixelated semiconductor detectors - such as the CdTe-Timepix detectors. It compromises a cadmium-telluride sensor of 14 mm x 14 mm x 1 mm size with an ASIC which has 256 x 256 pixel of 55 \\textmu m pixel pitch and can be used to obtain either spectroscopic or timing information in every pixel. In regular operation it can provide a 2D projection of particle trajectories; however, three dimensional trajectories are desirable for neutrinoless double beta decay and other applications. In this paper we present a method to obtain such trajectories. The method was developed and tested with simulations that assume some minor modifications to the Timepix ASIC. Also, we were able to test the method experimentally and in the best case achieved a position resolution of about 90 \\textmu m with electrons of 4.4 GeV.

  5. Cadmium telluride nanoparticles loaded on activated carbon as adsorbent for removal of sunset yellow

    Science.gov (United States)

    Ghaedi, M.; Hekmati Jah, A.; Khodadoust, S.; Sahraei, R.; Daneshfar, A.; Mihandoost, A.; Purkait, M. K.

    2012-05-01

    Adsorption is a promising technique for decolorization of effluents of textile dyeing industries but its application is limited due to requirement of high amounts of adsorbent required. The objective of this study was to assess the potential of cadmium telluride nanoparticles loaded onto activated carbon (CdTN-AC) for the removal of sunset yellow (SY) dye from aqueous solution. Adsorption studies were conducted in a batch mode varying solution pH, contact time, initial dye concentration, CdTN-AC dose, and temperature. In order to investigate the efficiency of SY adsorption on CdTN-AC, pseudo-first-order, pseudo-second-order, Elovich, and intra-particle diffusion kinetic models were studied. It was observed that the pseudo-second-order kinetic model fits better than other kinetic models with good correlation coefficient. Equilibrium data were fitted to the Langmuir model. Thermodynamic parameters such as enthalpy, entropy, activation energy, and sticking probability were also calculated. It was found that the sorption of SY onto CdTN-AC was spontaneous and endothermic in nature. The proposed adsorbent is applicable for SY removal from waste of real effluents including pea-shooter, orange drink and jelly banana with efficiency more than 97%.

  6. Two-color detector: Mercury-cadmium-telluride as a terahertz and infrared detector

    Energy Technology Data Exchange (ETDEWEB)

    Sizov, F.; Zabudsky, V.; Petryakov, V.; Golenkov, A.; Andreyeva, K.; Tsybrii, Z. [Institute of Semiconductor Physics, 03028 Kiev (Ukraine); Dvoretskii, S. [Institute of Semiconductor Physics of SB RAS, 630090 Novosibirsk (Russian Federation)

    2015-02-23

    In this paper, issues associated with the development of infrared (IR) and terahertz (THz) radiation detectors based on HgCdTe are discussed. Two-color un-cooled and cooled to 78 K narrow-gap mercury-cadmium-telluride semiconductor thin layers with antennas were considered both as sub-THz (sub-THz) direct detection bolometers and 3–10 μm IR photoconductors. The noise equivalent power (NEP) for one of the detectors studied at ν ≈ 140 GHz reaches NEP{sub 300 K} ≈ 4.5 × 10{sup −10} W/Hz{sup 1/2} and NEP{sub 78 K} ≈ 5 × 10{sup −9} W/Hz{sup 1/2}. The same detector used as an IR photoconductor showed the responsivity at temperatures T = 78 K and 300 K with signal-to-noise ratio S/N ≈ 750 and 50, respectively, under illumination by using IR monochromator and globar as a thermal source.

  7. Macro-loading Effects in Inductively Coupled Plasma Etched Mercury Cadmium Telluride

    Science.gov (United States)

    Apte, Palash; Rybnicek, Kimon; Stoltz, Andrew

    2016-09-01

    This paper reports the effect of macro-loading on mercury cadmium telluride (Hg1- x Cd x Te) and Photoresist (PR) etched in an inductively coupled plasma (ICP). A significant macro-loading effect is observed, which affects the etch rates of both PR and Hg1- x Cd x Te. It is observed that the exposed silicon area has a significant effect on the PR etch rate, but not on the Hg1- x Cd x Te etch rate. It is also observed that the exposed Hg1- x Cd x Te area has a significant effect on the etch rate of the PR, but the exposed PR area does not seem to have an effect on the Hg1- x Cd x Te etch rate. Further, the exposed Hg1- x Cd x Te area is shown to affect the etch rate of the Hg1- x Cd x Te, but there does not seem to be a similar effect for the exposed PR area on the etch rate of the PR. Since the macro-loading affects the selectivity significantly, this effect can cause significant problems in the etching of deep trenches. A few techniques to reduce the effect of macro-loading on the etch rates of the PR and Hg1- x Cd x Te are listed, herein.

  8. Measurement and Modeling of Blocking Contacts for Cadmium Telluride Gamma Ray Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Beck, Patrick R. [California Polytechnic State Univ. (CalPoly), San Luis Obispo, CA (United States)

    2010-01-07

    Gamma ray detectors are important in national security applications, medicine, and astronomy. Semiconductor materials with high density and atomic number, such as Cadmium Telluride (CdTe), offer a small device footprint, but their performance is limited by noise at room temperature; however, improved device design can decrease detector noise by reducing leakage current. This thesis characterizes and models two unique Schottky devices: one with an argon ion sputter etch before Schottky contact deposition and one without. Analysis of current versus voltage characteristics shows that thermionic emission alone does not describe these devices. This analysis points to reverse bias generation current or leakage through an inhomogeneous barrier. Modeling the devices in reverse bias with thermionic field emission and a leaky Schottky barrier yields good agreement with measurements. Also numerical modeling with a finite-element physics-based simulator suggests that reverse bias current is a combination of thermionic emission and generation. This thesis proposes further experiments to determine the correct model for reverse bias conduction. Understanding conduction mechanisms in these devices will help develop more reproducible contacts, reduce leakage current, and ultimately improve detector performance.

  9. Reproductive toxicity and gender differences induced by cadmium telluride quantum dots in an invertebrate model organism

    Science.gov (United States)

    Yan, Si-Qi; Xing, Rui; Zhou, Yan-Feng; Li, Kai-Le; Su, Yuan-Yuan; Qiu, Jian-Feng; Zhang, Yun-Hu; Zhang, Ke-Qin; He, Yao; Lu, Xiao-Ping; Xu, Shi-Qing

    2016-01-01

    Sexual glands are key sites affected by nanotoxicity, but there is no sensitive assay for measuring reproductive toxicity in animals. The aim of this study was to investigate the toxic effects of cadmium telluride quantum dots (CdTe-QDs) on gonads in a model organism, Bombyx mori. After dorsal vein injection of 0.32 nmol of CdTe-QDs per individual, the QDs passed through the outer membranes of gonads via the generation of ROS in the membranes of spermatocysts and ovarioles, as well as internal germ cells, thereby inducing early germ cell death or malformations via complex mechanisms related to apoptosis and autophagy through mitochondrial and lysosomal pathways. Histological observations of the gonads and quantitative analyses of germ cell development showed that the reproductive toxicity was characterized by obvious male sensitivity. Exposure to QDs in the early stage of males had severe adverse effects on the quantity and quality of sperm, which was the main reason for the occurrence of unfertilized eggs. Ala- or Gly-conjugated QDs could reduce the nanotoxicity of CdTe-QDs during germ cell development and fertilization of their offspring. The results demonstrate that males are preferable models for evaluating the reproductive toxicity of QDs in combined in vivo/in vitro investigations. PMID:27669995

  10. Electronic characterization of defects in narrow gap semiconductors: Comparison of electronic energy levels and formation energies in mercury cadmium telluride, mercury zinc telluride, and mercury zinc selenide

    Science.gov (United States)

    Patterson, James D.; Li, Wei-Gang

    1995-01-01

    The project has evolved to that of using Green's functions to predict properties of deep defects in narrow gap materials. Deep defects are now defined as originating from short range potentials and are often located near the middle of the energy gap. They are important because they affect the lifetime of charge carriers and hence the switching time of transistors. We are now moving into the arena of predicting formation energies of deep defects. This will also allow us to make predictions about the relative concentrations of the defects that could be expected at a given temperature. The narrow gap materials mercury cadmium telluride (MCT), mercury zinc telluride (MZT), and mercury zinc selenide (MZS) are of interest to NASA because they have commercial value for infrared detecting materials, and because there is a good possibility that they can be grown better in a microgravity environment. The uniform growth of these crystals on earth is difficult because of convection (caused by solute depletion just ahead of the growing interface, and also due to thermal gradients). In general it is very difficult to grow crystals with both radial and axial homogeneity.

  11. Characterization of cadmium manganese telluride (Cd1-xMnxTe) crystals grown by floating zone method

    Science.gov (United States)

    Hossain, A.; Gu, G. D.; Bolotnikov, A. E.; Camarda, G. S.; Cui, Y.; Gul, R.; Roy, U. N.; Yang, G.; Liu, T.; Zhong, R.; Schneeloch, J.; James, R. B.

    2014-09-01

    Recently, Cadmium Manganese Telluride (CMT) emerged as a promising material for roomtemperature X- and gamma-ray detectors. However, our studies revealed several material defects primarily related to growth processes that are impeding the production of large single crystals with high resistivity and high mobility-lifetime product. In this work, we characterized various defects in materials grown by the floating zone method, including twins, Te inclusions, and dislocations, using our unique facilities. We also fabricated detectors from selected CMT crystals and tested their performance. This paper discusses our detailed findings on the material's properties and the performance of fabricated CMT detectors.

  12. Chemiluminescence studies between aqueous phase synthesized mercaptosuccinic acid capped cadmium telluride quantum dots and luminol-H2O2

    Science.gov (United States)

    Kaviyarasan, Kulandaivelu; Anandan, Sambandam; Mangalaraja, Ramalinga Viswanathan; Asiri, Abdullah M.; Wu, Jerry J.

    2016-08-01

    Mercaptosuccinic acid capped Cadmium telluride quantum dots have been successfully synthesized via aqueous phase method. The products were well characterized by a number of analytical techniques, including FT-IR, XRD, HRTEM, and a corrected particle size analysis by the statistical treatment of several AFM measurements. Chemiluminescence experiments were performed to explore the resonance energy transfer between chemiluminescence donor (luminol-H2O2 system) and acceptor CdTe QDs. The combination of such donor and acceptor dramatically reduce the fluorescence while compared to pristine CdTe QDs without any exciting light source, which is due to the occurrence of chemiluminescence resonance energy transfer (CRET) processes.

  13. On the possible role played by tunnel recombination in the loss processes of excess current carriers in cadmium telluride

    Science.gov (United States)

    Novikov, G. F.; Marinin, A. A.; Gapanovich, M. V.; Rabenok, E. V.

    2010-05-01

    The microwave photoconductivity method was used to study the kinetics of the decay of current carriers generated by nitrogen laser pulses in n- and p-type cadmium telluride. The dependences of the shape and amplitude of photoresponse decays on temperature and light intensity were studied. Photoresponse decays contained "fast" (at t 50 ns) components. At long times, the dependence of photoresponse on the logarithm of time was linear. The shape of slow component decays was almost independent of temperature. The slow component of photoresponse decay could correspond to the loss process of entrapped charges in tunnel recombination.

  14. Chemiluminescence studies between aqueous phase synthesized mercaptosuccinic acid capped cadmium telluride quantum dots and luminol-H2O2.

    Science.gov (United States)

    Kaviyarasan, Kulandaivelu; Anandan, Sambandam; Mangalaraja, Ramalinga Viswanathan; Asiri, Abdullah M; Wu, Jerry J

    2016-08-01

    Mercaptosuccinic acid capped Cadmium telluride quantum dots have been successfully synthesized via aqueous phase method. The products were well characterized by a number of analytical techniques, including FT-IR, XRD, HRTEM, and a corrected particle size analysis by the statistical treatment of several AFM measurements. Chemiluminescence experiments were performed to explore the resonance energy transfer between chemiluminescence donor (luminol-H2O2 system) and acceptor CdTe QDs. The combination of such donor and acceptor dramatically reduce the fluorescence while compared to pristine CdTe QDs without any exciting light source, which is due to the occurrence of chemiluminescence resonance energy transfer (CRET) processes. PMID:27131144

  15. Cadmium zinc telluride based infrared interferometry for X-ray detection

    Energy Technology Data Exchange (ETDEWEB)

    Lohstroh, A., E-mail: A.Lohstroh@surrey.ac.uk; Della Rocca, I. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Parsons, S. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); AWE Aldermaston, Reading RG7 4PR (United Kingdom); Langley, A.; Shenton-Taylor, C.; Blackie, D. [AWE Aldermaston, Reading RG7 4PR (United Kingdom)

    2015-02-09

    Cadmium Zinc Telluride (CZT) is a wide band gap semiconductor for room temperature radiation detection. The electro-optic Pockels effect of the material has been exploited in the past to study electric field non-uniformities and their consequence on conventional detector signals in CZT, by imaging the intensity distribution of infrared (IR) light transmitted through a device placed between crossed polarizers. Recently, quantitative monitoring of extremely high intensity neutron pulses through the change of transmitted IR intensity was demonstrated, offering the advantage to place sensitive electronics outside the measured radiation field. In this work, we demonstrate that X-ray intensity can be deduced directly from measuring the change in phase of 1550 nm laser light transmitted through a 7 × 7 × 2 mm{sup 3} CZT based Pockels cell in a simple Mach Zehnder interferometer. X-rays produced by a 50 kVp Mo X-ray tube incident on the CZT cathode surface placed at 7 mm distance cause a linearly increasing phase shift above 0.3 mA tube current, with 1.58 ± 0.02 rad per mA for an applied bias of 500 V across the 2 mm thick device. Pockels images confirm that the sample properties are in agreement with the literature, exhibiting electric field enhancement near the cathode under irradiation, which may cause the non-linearity at low X-ray tube anode current settings. The laser used to probe the X-ray intensity causes itself some space charge, whose spatial distribution does not seem to be exclusively determined by the incident laser position, i.e., charge carrier generation location, with respect to the electrodes.

  16. Cadmium zinc telluride based infrared interferometry for X-ray detection

    International Nuclear Information System (INIS)

    Cadmium Zinc Telluride (CZT) is a wide band gap semiconductor for room temperature radiation detection. The electro-optic Pockels effect of the material has been exploited in the past to study electric field non-uniformities and their consequence on conventional detector signals in CZT, by imaging the intensity distribution of infrared (IR) light transmitted through a device placed between crossed polarizers. Recently, quantitative monitoring of extremely high intensity neutron pulses through the change of transmitted IR intensity was demonstrated, offering the advantage to place sensitive electronics outside the measured radiation field. In this work, we demonstrate that X-ray intensity can be deduced directly from measuring the change in phase of 1550 nm laser light transmitted through a 7 × 7 × 2 mm3 CZT based Pockels cell in a simple Mach Zehnder interferometer. X-rays produced by a 50 kVp Mo X-ray tube incident on the CZT cathode surface placed at 7 mm distance cause a linearly increasing phase shift above 0.3 mA tube current, with 1.58 ± 0.02 rad per mA for an applied bias of 500 V across the 2 mm thick device. Pockels images confirm that the sample properties are in agreement with the literature, exhibiting electric field enhancement near the cathode under irradiation, which may cause the non-linearity at low X-ray tube anode current settings. The laser used to probe the X-ray intensity causes itself some space charge, whose spatial distribution does not seem to be exclusively determined by the incident laser position, i.e., charge carrier generation location, with respect to the electrodes

  17. Mercury-Cadmium-Telluride Focal Plane Array Performance Under Non-Standard Operating Conditions

    Science.gov (United States)

    Richardson, Brandon S.; Eastwood, Michael L.; Bruce, Carl F.; Green, Robert O.; Coles, J. B.

    2011-01-01

    This paper highlights a new technique that allows the Teledyne Scientific & Imaging LLC TCM6604A Mercury-Cadmium-Telluride (MCT) Focal Plane Array (FPA) to operate at room temperature. The Teledyne MCT FPA has been a standard in Imaging Spectroscopy since its creation in the 1980's. This FPA has been used in applications ranging from space instruments such as CRISM, M3 and ARTEMIS to airborne instruments such as MaRS and the Next Generation AVIRIS Instruments1. Precise focal plane alignment is always a challenge for such instruments. The current FPA alignment process results in multiple cold cycles requiring week-long durations, thereby increasing the risk and cost of a project. These alignment cycles are necessary because optimal alignment is approached incrementally and can only be measured with the FPA and Optics at standard operating conditions, requiring a cold instrument. Instruments using this FPA are normally cooled to temperatures below 150K for the MCT FPA to properly function. When the FPA is run at higher temperatures the dark current increases saturating the output. This paper covers the prospect of warm MCT FPA operation from a theoretical and experimental perspective. We discuss the empirical models and physical laws that govern MCT material properties and predict the optimal settings that will result in the best MCT PA performance at 300K. Theoretical results are then calculated for the proposed settings. We finally present the images and data obtained using the actual system with the warm MCT FPA settings. The paper concludes by emphasizing the strong positive correlation between the measured values and the theoretical results.

  18. Development and evaluation of polycrystalline cadmium telluride dosimeters for accurate quality assurance in radiation therapy

    Science.gov (United States)

    Oh, K.; Han, M.; Kim, K.; Heo, Y.; Moon, C.; Park, S.; Nam, S.

    2016-02-01

    For quality assurance in radiation therapy, several types of dosimeters are used such as ionization chambers, radiographic films, thermo-luminescent dosimeter (TLD), and semiconductor dosimeters. Among them, semiconductor dosimeters are particularly useful for in vivo dosimeters or high dose gradient area such as the penumbra region because they are more sensitive and smaller in size compared to typical dosimeters. In this study, we developed and evaluated Cadmium Telluride (CdTe) dosimeters, one of the most promising semiconductor dosimeters due to their high quantum efficiency and charge collection efficiency. Such CdTe dosimeters include single crystal form and polycrystalline form depending upon the fabrication process. Both types of CdTe dosimeters are commercially available, but only the polycrystalline form is suitable for radiation dosimeters, since it is less affected by volumetric effect and energy dependence. To develop and evaluate polycrystalline CdTe dosimeters, polycrystalline CdTe films were prepared by thermal evaporation. After that, CdTeO3 layer, thin oxide layer, was deposited on top of the CdTe film by RF sputtering to improve charge carrier transport properties and to reduce leakage current. Also, the CdTeO3 layer which acts as a passivation layer help the dosimeter to reduce their sensitivity changes with repeated use due to radiation damage. Finally, the top and bottom electrodes, In/Ti and Pt, were used to have Schottky contact. Subsequently, the electrical properties under high energy photon beams from linear accelerator (LINAC), such as response coincidence, dose linearity, dose rate dependence, reproducibility, and percentage depth dose, were measured to evaluate polycrystalline CdTe dosimeters. In addition, we compared the experimental data of the dosimeter fabricated in this study with those of the silicon diode dosimeter and Thimble ionization chamber which widely used in routine dosimetry system and dose measurements for radiation

  19. Investigations of portable cadmium telluride (CdTe(Cl)) detectors for clinical studies with radioactive indicators

    International Nuclear Information System (INIS)

    The combination of small, portable γ-radiation-sensitive Cadmium Telluride (CdTE(Cl)) crystal detectors and portable solid state data storage memories makes it feasible to extend the measuring period in a number of clinical investigations based on the use of various radioisotopes and external detection. Blood sampling can be avoided in some cases. Continuous ambulatory monitoring of relevant physiological parameters is practicable, e.g. kidney function (GFR), left ventricular ejection fraction, subcutaneous blood flow, muscle blood flow and insulin absorption in diabetic patients. In the present methodological study the applicability of the 133-Xe washout technique to subcutaneous (s.c.) adipose tissue blood flow (SBF) has been investigated and adapted to the use of CdTe(Cl) detectors attached to the skin surface for the measurement of local 133-Xe-disappearance rate constants (k). Physical characterization of CdTe(Cl) detectors as γ-sensitive devices has been performed, and adequate counting sensitivities were found without detector energy-resolution properties. The CdTe(Cl) detectors are therefore suitable for single indicator studies. The measuring geometry of CdTe(Cl) detectors was studied and compared with that of stationary Sodium Iodide (NaI(Tl)) detectors in both phantom and in vivo investigations. The spatial properties of CdTe(Cl) detectors could to some extent be adjusted by pulse height discrimination and lead collimation. When long-term measurements were complicated by for instance physical activity of the patients, the small CdTe(Cl) detectors in general showed equal or better performance than the heavy and voluminous NaI(Tl) detectors. The free movement of the ambulatory patient and the avoidance of cable connections to stationary data-collecting systems gave improved possibilities for measurements of the relevant parameters. From this point of view, portable CdTe(Cl) detectors must be considered an important advance for radioactivity studies in

  20. Electronic Characterization of Defects in Narrow Gap Semiconductors-Comparison of Electronic Energy Levels and Formation Energies in Mercury Cadmium Telluride, Mercury Zinc Telluride, and Mercury Zinc Selenide

    Science.gov (United States)

    Patterson, James D.

    1996-01-01

    We have used a Green's function technique to calculate the energy levels and formation energy of deep defects in the narrow gap semiconductors mercury cadmium telluride (MCT), mercury zinc telluride (MZT) and mercury zinc selenide (MZS). The formation energy is calculated from the difference between the total energy with an impurity cluster and the total energy for the perfect crystal. Substitutional (including antisite), interstitial (self and foreign), and vacancy deep defects are considered. Relaxation effects are calculated (with molecular dynamics). By use of a pseudopotential, we generalize the ideal vacancy model so as to be able to consider relaxation for vacancies. Different charge states are considered and the charged state energy shift (as computed by a modified Haldane-Anderson model) can be twice that due to relaxation. Different charged states for vacancies were not calculated to have much effect on the formation energy. For all cases we find deep defects in the energy gap only for cation site s-like orbitals or anion site p-like orbitals, and for the substitutional case only the latter are appreciably effected by relaxation. For most cases for MCT, MZT, MZS, we consider x (the concentration of Cd or Zn) in the range appropriate for a band gap of 0.1 eV. For defect energy levels, the absolute accuracy of our results is limited, but the precision is good, and hence chemical trends are accurately predicted. For the same reason, defect formation energies are more accurately predicted than energy level position. We attempt, in Appendix B, to calculate vacancy formation energies using relatively simple chemical bonding ideas due to Harrison. However, these results are only marginally accurate for estimating vacancy binding energies. Appendix C lists all written reports and publications produced for the grant. We include abstracts and a complete paper that summarizes our work which is not yet available.

  1. Microbial toxicity of ionic species leached from the II-VI semiconductor materials, cadmium telluride (CdTe) and cadmium selenide (CdSe).

    Science.gov (United States)

    Ramos-Ruiz, Adriana; Zeng, Chao; Sierra-Alvarez, Reyes; Teixeira, Luiz H; Field, Jim A

    2016-11-01

    This work investigated the microbial toxicity of soluble species that can potentially be leached from the II-VI semiconductor materials, cadmium telluride and cadmium selenide. The soluble ions tested included: cadmium, selenite, selenate, tellurite, and tellurate. Their toxicity towards the acetoclastic and hydrogen-consuming trophic groups in a methanogenic consortium as well as towards a bioluminescent marine bacterium, Aliivibrio fischeri (Microtox(®) test), was assessed. The acetoclastic methanogenic activity was the most affected as evidenced by the low 50% inhibiting concentrations (IC50) values obtained of 8.6 mg L(-1) for both cadmium and tellurite, 10.2 mg L(-1) for tellurate, and 24.1 mg L(-1) for selenite. Both tellurium oxyanions caused a strong inhibition of acetoclastic methanogenesis at low concentrations, each additional increment in concentration provided progressively less inhibition increase. In the case of the hydrogenotrophic methanogenesis, cadmium followed by selenite caused the greatest inhibition with IC50 values of 2.9 and 18.0 mg L(-1), respectively. Tellurite caused a moderate effect as evidenced by a 36.8% inhibition of the methanogenic activity at the highest concentration tested, and a very mild effect of tellurate was observed. Microtox(®) analyses showed a noteworthy inhibition of cadmium, selenite, and tellurite with 50% loss in bioluminescence after 30 min of exposure of 5.5, 171.1, and 458.6 mg L(-1), respectively. These results suggest that the leaching of cadmium, tellurium and selenium ions from semiconductor materials can potentially cause microbial toxicity.

  2. Microbial toxicity of ionic species leached from the II-VI semiconductor materials, cadmium telluride (CdTe) and cadmium selenide (CdSe).

    Science.gov (United States)

    Ramos-Ruiz, Adriana; Zeng, Chao; Sierra-Alvarez, Reyes; Teixeira, Luiz H; Field, Jim A

    2016-11-01

    This work investigated the microbial toxicity of soluble species that can potentially be leached from the II-VI semiconductor materials, cadmium telluride and cadmium selenide. The soluble ions tested included: cadmium, selenite, selenate, tellurite, and tellurate. Their toxicity towards the acetoclastic and hydrogen-consuming trophic groups in a methanogenic consortium as well as towards a bioluminescent marine bacterium, Aliivibrio fischeri (Microtox(®) test), was assessed. The acetoclastic methanogenic activity was the most affected as evidenced by the low 50% inhibiting concentrations (IC50) values obtained of 8.6 mg L(-1) for both cadmium and tellurite, 10.2 mg L(-1) for tellurate, and 24.1 mg L(-1) for selenite. Both tellurium oxyanions caused a strong inhibition of acetoclastic methanogenesis at low concentrations, each additional increment in concentration provided progressively less inhibition increase. In the case of the hydrogenotrophic methanogenesis, cadmium followed by selenite caused the greatest inhibition with IC50 values of 2.9 and 18.0 mg L(-1), respectively. Tellurite caused a moderate effect as evidenced by a 36.8% inhibition of the methanogenic activity at the highest concentration tested, and a very mild effect of tellurate was observed. Microtox(®) analyses showed a noteworthy inhibition of cadmium, selenite, and tellurite with 50% loss in bioluminescence after 30 min of exposure of 5.5, 171.1, and 458.6 mg L(-1), respectively. These results suggest that the leaching of cadmium, tellurium and selenium ions from semiconductor materials can potentially cause microbial toxicity. PMID:27494313

  3. Inhibition of autophagy contributes to the toxicity of cadmium telluride quantum dots in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Fan J

    2016-07-01

    Full Text Available Junpeng Fan,1–4 Ming Shao,1–4 Lu Lai,3–5 Yi Liu,3–5 Zhixiong Xie1–4,6 1College of Life Sciences, Wuhan University, 2Hubei Provincial Cooperative Innovation Center of Industrial Fermentation,3State Key Laboratory of Virology, 4Key Laboratory of Analytical Chemistry for Biology and Medicine (MOE, 5College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 6School of Life Science and Technology, Hubei Engineering University, Xiaogan, People’s Republic of China Abstract: Cadmium telluride quantum dots (CdTe QDs are used as near-infrared probes in biologic and medical applications, but their cytological effects and mechanism of potential toxicity are still unclear. In this study, we evaluated the toxicity of CdTe QDs of different sizes and investigated their mechanism of toxicity in the yeast Saccharomyces cerevisiae. A growth inhibition assay revealed that orange-emitting CdTe (O-CdTe QDs (half inhibitory concentration [IC50] =59.44±12.02 nmol/L were more toxic than green-emitting CdTe QDs (IC50 =186.61±19.74 nmol/L to S. cerevisiae. Further studies on toxicity mechanisms using a transmission electron microscope and green fluorescent protein tagged Atg8 processing assay revealed that O-CdTe QDs could partially inhibit autophagy at a late stage, which differs from the results reported in mammalian cells. Moreover, autophagy inhibited at a late stage by O-CdTe QDs could be partially recovered by enhancing autophagy with rapamycin (an autophagy activator, combined with an increased number of living cells. These results indicate that inhibition of autophagy acts as a toxicity mechanism of CdTe QDs in S. cerevisiae. This work reports a novel toxicity mechanism of CdTe QDs in yeast and provides valuable information on the effect of CdTe QDs on the processes of living cells. Keywords: CdTe quantum dots, Saccharomyces cerevisiae, toxicity, autophagy

  4. A rapid and sensitive assay for determination of doxycycline using thioglycolic acid-capped cadmium telluride quantum dots

    Science.gov (United States)

    Tashkhourian, Javad; Absalan, Ghodratollah; Jafari, Marzieh; Zare, Saber

    2016-01-01

    A rapid, simple and inexpensive spectrofluorimetric sensor for determination of doxycycline based on its interaction with thioglycolic acid-capped cadmium telluride quantum dots (TGA/CdTe QDs) has been developed. Under the optimum experimental conditions, the sensor exhibited a fast response time of doxycycline could quench the fluorescence of TGA/CdTe QDs via electron transfer from the QDs to doxycycline through a dynamic quenching mechanism. The sensor permitted determination of doxycycline in a concentration range of 1.9 × 10-6-6.1 × 10-5 mol L-1 with a detection limit of 1.1 × 10-7 mol L-1. The sensor was applied for determination of doxycycline in honey and human serum samples.

  5. Baseline Evaluation of Thin-Film Amorphous Silicon, Copper Indium Diselenide, and Cadmium Telluride for the 21st Century: Preprint

    International Nuclear Information System (INIS)

    This paper examines three thin-film PV technologies: amorphous silicon, cadmium telluride, and copper indium selenide. The purpose is to: (1) assess their status and potential; (2) provide an improved set of criteria for comparing these existing thin films against any new PV technological alternatives, and examining the longer-term (c. 2050) potential of thin films to meet cost goals that would be competitive with conventional sources of energy without any added value from the substantial environmental advantages of PV. Among the conclusions are: (1) today's thin films have substantial economic potential, (2) any new approach to PV should be examined against the substantial achievements and potential of today's thin films, (3) the science and technology base of today's thin films needs substantial strengthening, (4) some need for alternative technologies exists, especially as the future PV marketplace expands beyond about 30 GW of annual production

  6. Crystal Growth, Characterization and Fabrication of Cadmium Zinc Telluride-based Nuclear Detectors

    Science.gov (United States)

    Krishna, Ramesh M.

    In today's world, nuclear radiation is seeing more and more use by humanity as time goes on. Nuclear power plants are being built to supply humanity's energy needs, nuclear medical imaging is becoming more popular for diagnosing cancer and other diseases, and control of weapons-grade nuclear materials is becoming more and more important for national security. All of these needs require high-performance nuclear radiation detectors which can accurately measure the type and amount of radiation being used. However, most current radiation detection materials available commercially require extensive cooling, or simply do not function adequately for high-energy gamma-ray emitting nuclear materials such as uranium and plutonium. One of the most promising semiconductor materials being considered to create a convenient, field-deployable nuclear detector is cadmium zinc telluride (CdZnTe, or CZT). CZT is a ternary semiconductor compound which can detect high-energy gamma-rays at room temperature. It offers high resistivity (≥ 1010 O-cm), a high band gap (1.55 eV), and good electron transport properties, all of which are required for a nuclear radiation detector. However, one significant issue with CZT is that there is considerable difficulty in growing large, homogeneous, defect-free single crystals of CZT. This significantly increases the cost of producing CZT detectors, making CZT less than ideal for mass-production. Furthermore, CZT suffers from poor hole transport properties, which creates significant problems when using it as a high-energy gamma-ray detector. In this dissertation, a comprehensive investigation is undertaken using a successful growth method for CZT developed at the University of South Carolina. This method, called the solvent-growth technique, reduces the complexity required to grow detector-grade CZT single crystals. It utilizes a lower growth temperature than traditional growth methods by using Te as a solvent, while maintaining the advantages of

  7. Controlled cadmium telluride thin films for solar-cell applications. Final technical report, June 1, 1980-May 31, 1981

    Energy Technology Data Exchange (ETDEWEB)

    Das, M.B.; Krishnaswamy, S.V.

    1981-06-01

    The objectives of this contract were to carry out a systematic study on the preparation and characterization of rf-sputtered CdTe thin films in order to establish reproducibility of the films with good electrical characteristics and to demonstrate the feasibility of fabricating various types of junctions and ohmic contacts with reproducible characteristics and finally to optimize the most promising solar cell structure in order to achieve an efficiency of 6% or higher. Efforts have been directed to the control of various sputtering parameters in order to obtain good quality films. The structure, crystallographic, compositional and electrical properties of cadmium telluride films sputtered over a wide range of conditions have been evaluated. A series of doping experiments have been carried out using primarily Cd, Te, In, as the n-type dopants and Cu as the p-type dopant. Of these dopants, indium doping provided films with which S.B. junctions can be obtained for further electrical characterization. Use of cadmium overpressure during CdTe:In sputtering has improved the film characteristics. Ion Beam Sputtering was attempted as an alternative technique for film preparation. For lack of time and due to a number of mechanical failures, no significant results could be obtained.

  8. Thermoelectrically-cooled Cadmium Zinc Telluride detectors (CZT) for X-ray and gamma-ray detection

    International Nuclear Information System (INIS)

    Recently, Cadmium Zinc Telluride (CZT) became one of the most promising room temperature semiconductor detectors. Although significant progress has been made in the growth and characterization of CZT crystals, the energy resolution of CZT detectors at room temperature is still limited by leakage current and the charge transport effects. To optimize the performance of the room temperature CZT detectors a compromise should be made when selecting the shaping time constant of the spectroscopy amplifier. A short shaping time constant reduces leakage current fluctuations. However, the short pulse shapes are more sensitive to ballistic deficit and charge collection fluctuations. In addition, when short shaping time constants are used, the charge sensitive preamplifier noise limits the energy resolution, especially when low energy X-rays are detected. It is therefore important to reduce the leakage current of the detector and to keep the preamplifier noise as low as possible. One way to do this is to cool the detector, the front stage, and the feedback components of the preamplifier. This paper describes a compact, thermoelectrically-cooled radiation detector using a CZT crystal, designated the XR-100T-CZT. (J.P.N.)

  9. Improved Sensitization of Zinc Oxide Nanorods by Cadmium Telluride Quantum Dots through Charge Induced Hydrophilic Surface Generation

    Directory of Open Access Journals (Sweden)

    Karthik Laxman

    2014-01-01

    Full Text Available This paper reports on UV-mediated enhancement in the sensitization of semiconductor quantum dots (QDs on zinc oxide (ZnO nanorods, improving the charge transfer efficiency across the QD-ZnO interface. The improvement was primarily due to the reduction in the interfacial resistance achieved via the incorporation of UV light induced surface defects on zinc oxide nanorods. The photoinduced defects were characterized by XPS, FTIR, and water contact angle measurements, which demonstrated an increase in the surface defects (oxygen vacancies in the ZnO crystal, leading to an increase in the active sites available for the QD attachment. As a proof of concept, a model cadmium telluride (CdTe QD solar cell was fabricated using the defect engineered ZnO photoelectrodes, which showed ∼10% increase in photovoltage and ∼66% improvement in the photocurrent compared to the defect-free photoelectrodes. The improvement in the photocurrent was mainly attributed to the enhancement in the charge transfer efficiency across the defect rich QD-ZnO interface, which was indicated by the higher quenching of the CdTe QD photoluminescence upon sensitization.

  10. Measurement of the electrical properties of a polycrystalline cadmium telluride for direct conversion flat panel x-ray detector

    International Nuclear Information System (INIS)

    Cadmium telluride (CdTe) is one of the best candidate direct conversion material for medical X-ray application because it satisfies the requirements of direct conversion x-ray material such as high atomic absorption, density, bandgap energy, work fuction, and resistivity. With such properties, single crystal CdTe exhibits high quantum efficiency and charge collection efficiency. However, for the development of low-cost large area detector, the study of the improvement of polycrystalline CdTe property is desirable. In this study, in order to improve the properties of polycrystalline CdTe, we produced polycrystalline CdTe with different kinds of raw materials, high purity Cd and Te powder compounds and bulk CdTe compound synthesized from single crystal CdTe. The electric properties including resistivity, x-ray sensitivity, and charge transport properties were investigated. As a result, polycrystalline CdTe exhibited simular level of resistivity and x-ray sensitivity to single crystal CdTe. The carrier transport properties of polycrystalline CdTe showed poorer properties than those of single crystal CdTe due to significant charge trapping. However, the polycrystalline CdTe fabricated with bulk CdTe compound synthesized from single crystal CdTe showed better charge transport properties than the polycrystalline CdTe fabricated with CdTe powder compounds. This is suitable for diagnostic x-ray detectors, especially for digital fluoroscopy

  11. Liver Toxicity of Cadmium Telluride Quantum Dots (CdTe QDs Due to Oxidative Stress in Vitro and in Vivo

    Directory of Open Access Journals (Sweden)

    Ting Zhang

    2015-09-01

    Full Text Available With the applications of quantum dots (QDs expanding, many studies have described the potential adverse effects of QDs, yet little attention has been paid to potential toxicity of QDs in the liver. The aim of this study was to investigate the effects of cadmium telluride (CdTe QDs in mice and murine hepatoma cells alpha mouse liver 12 (AML 12. CdTe QDs administration significantly increased the level of lipid peroxides marker malondialdehyde (MDA in the livers of treated mice. Furthermore, CdTe QDs caused cytotoxicity in AML 12 cells in a dose- and time-dependent manner, which was likely mediated through the generation of reactive oxygen species (ROS and the induction of apoptosis. An increase in ROS generation with a concomitant increase in the gene expression of the tumor suppressor gene p53, the pro-apoptotic gene Bcl-2 and a decrease in the anti-apoptosis gene Bax, suggested that a mitochondria mediated pathway was involved in CdTe QDs’ induced apoptosis. Finally, we showed that NF-E2-related factor 2 (Nrf2 deficiency blocked induced oxidative stress to protect cells from injury induced by CdTe QDs. These findings provide insights into the regulatory mechanisms involved in the activation of Nrf2 signaling that confers protection against CdTe QDs-induced apoptosis in hepatocytes.

  12. A novel approach of chemical mechanical polishing using environment-friendly slurry for mercury cadmium telluride semiconductors

    Science.gov (United States)

    Zhang, Zhenyu; Wang, Bo; Zhou, Ping; Guo, Dongming; Kang, Renke; Zhang, Bi

    2016-03-01

    A novel approach of chemical mechanical polishing (CMP) is developed for mercury cadmium telluride (HgCdTe or MCT) semiconductors. Firstly, fixed-abrasive lapping is used to machine the MCT wafers, and the lapping solution is deionized water. Secondly, the MCT wafers are polished using the developed CMP slurry. The CMP slurry consists of mainly SiO2 nanospheres, H2O2, and malic and citric acids, which are different from previous CMP slurries, in which corrosive and toxic chemical reagents are usually employed. Finally, the polished MCT wafers are cleaned and dried by deionized water and compressed air, respectively. The novel approach of CMP is environment-friendly. Surface roughness Ra, and peak-to-valley (PV) values of 0.45, and 4.74 nm are achieved, respectively on MCT wafers after CMP. The first and second passivating processes are observed in electrochemical measurements on MCT wafers. The fundamental mechanisms of CMP are proposed according to the X-ray photoelectron spectroscopy (XPS) and electrochemical measurements. Malic and citric acids dominate the first passivating process, and the CMP slurry governs the second process. Te4+3d peaks are absent after CMP induced by the developed CMP slurry, indicating the removing of oxidized films on MCT wafers, which is difficult to achieve using single H2O2 and malic and citric acids solutions.

  13. SemiSPECT: A small-animal single-photon emission computed tomography (SPECT) imager based on eight cadmium zinc telluride (CZT) detector arrays

    OpenAIRE

    Kim, Hyunki; Furenlid, Lars R.; Crawford, Michael J.; Wilson, Donald W.; Barber, H. Bradford; Todd E. Peterson; Hunter, William C. J.; Liu, Zhonglin; Woolfenden, James M.; Barrett, Harrison H.

    2006-01-01

    The first full single-photon emission computed tomography (SPECT) imager to exploit eight compact high-intrinsic-resolution cadmium zinc telluride (CZT) detectors, called SemiSPECT, has been completed. Each detector consists of a CZT crystal and a customized application-specific integrated circuit (ASIC). The CZT crystal is a 2.7 cm × 2.7 cm × ~ 0.2 cm slab with a continuous top electrode and a bottom electrode patterned into a 64 × 64 pixel array by photolithography. The ASIC is attached to ...

  14. Comparison between stress myocardial perfusion SPECT recorded with cadmium-zinc-telluride and Anger cameras in various study protocols

    Energy Technology Data Exchange (ETDEWEB)

    Verger, Antoine; Karcher, Gilles [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); INSERM U947, Nancy (France); Nancyclotep Experimental Imaging Platform, Nancy (France); Djaballah, Wassila [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); INSERM U947, Nancy (France); Fourquet, Nicolas [Clinique Pasteur, Toulouse (France); Rouzet, Francois; Le Guludec, Dominique [AP-HP, Hopital Bichat, Department of Nuclear Medicine, Paris (France); INSERM U 773 Inserm and Denis Diderot University, Paris (France); Koehl, Gregoire; Roch, Veronique [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); Nancyclotep Experimental Imaging Platform, Nancy (France); Imbert, Laetitia [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); Nancyclotep Experimental Imaging Platform, Nancy (France); Centre Alexis Vautrin, Department of Radiotherapy, Vandoeuvre (France); Poussier, Sylvain [INSERM U947, Nancy (France); Nancyclotep Experimental Imaging Platform, Nancy (France); Fay, Renaud [INSERM, Centre d' Investigation Clinique CIC-P 9501, Nancy (France); Marie, Pierre-Yves [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); Nancyclotep Experimental Imaging Platform, Nancy (France); INSERM U961, Nancy (France); Hopital de Brabois, CHU-Nancy, Medecine Nucleaire, Vandoeuvre-les-Nancy (France)

    2013-03-15

    The results of stress myocardial perfusion SPECT could be enhanced by new cadmium-zinc-telluride (CZT) cameras, although differences compared to the results with conventional Anger cameras remain poorly known for most study protocols. This study was aimed at comparing the results of CZT and Anger SPECT according to various study protocols while taking into account the influence of obesity. The study population, which was from three different institutions equipped with identical CZT cameras, comprised 276 patients referred for study using protocols involving {sup 201}Tl (n = 120) or {sup 99m}Tc-sestamibi injected at low dose at stress ({sup 99m}Tc-Low; stress/rest 1-day protocol; n = 110) or at high dose at stress ({sup 99m}Tc-High; rest/stress 1-day or 2-day protocol; n = 46). Each Anger SPECT scan was followed by a high-speed CZT SPECT scan (2 to 4 min). Agreement rates between CZT and Anger SPECT were good irrespective of the study protocol (for abnormal SPECT, {sup 201}Tl 92 %, {sup 99m}Tc-Low 86 %, {sup 99m}Tc-High 98 %), although quality scores were much higher for CZT SPECT with all study protocols. Overall correlations were high for the extent of myocardial infarction (r = 0.80) and a little lower for ischaemic areas (r = 0.72), the latter being larger on Anger SPECT (p < 0.001). This larger extent was mainly observed in 50 obese patients who were in the {sup 201}Tl or {sup 99m}Tc-Low group and in whom stress myocardial counts were particularly low with Anger SPECT (228 {+-} 101 kcounts) and dramatically enhanced with CZT SPECT (+279 {+-} 251 %). Concordance between the results of CZT and Anger SPECT is good regardless of study protocol and especially when excluding obese patients who have low-count Anger SPECT and for whom myocardial counts are dramatically enhanced on CZT SPECT. (orig.)

  15. Downstream resource utilization following hybrid cardiac imaging with an integrated cadmium-zinc-telluride/64-slice CT device

    International Nuclear Information System (INIS)

    Low yield of invasive coronary angiography and unnecessary coronary interventions have been identified as key cost drivers in cardiology for evaluation of coronary artery disease (CAD). This has fuelled the search for noninvasive techniques providing comprehensive functional and anatomical information on coronary lesions. We have evaluated the impact of implementation of a novel hybrid cadmium-zinc-telluride (CZT)/64-slice CT camera into the daily clinical routine on downstream resource utilization. Sixty-two patients with known or suspected CAD were referred for same-day single-session hybrid evaluation with CZT myocardial perfusion imaging (MPI) and coronary CT angiography (CCTA). Hybrid MPI/CCTA images from the integrated CZT/CT camera served for decision-making towards conservative versus invasive management. Based on the hybrid images patients were classified into those with and those without matched findings. Matched findings were defined as the combination of MPI defect with a stenosis by CCTA in the coronary artery subtending the respective territory. All patients with normal MPI and CCTA as well as those with isolated MPI or CCTA finding or combined but unmatched findings were categorized as ''no match''. All 23 patients with a matched finding underwent invasive coronary angiography and 21 (91%) were revascularized. Of the 39 patients with no match, 5 (13%, p < 0.001 vs matched) underwent catheterization and 3 (8%, p < 0.001 vs matched) were revascularized. Cardiac hybrid imaging in CAD evaluation has a profound impact on patient management and may contribute to optimal downstream resource utilization. (orig.)

  16. Myocardial perfusion imaging with a cadmium zinc telluride-based gamma camera versus invasive fractional flow reserve

    Energy Technology Data Exchange (ETDEWEB)

    Mouden, Mohamed [Isala klinieken, Department of Cardiology, Zwolle (Netherlands); Isala klinieken, Department of Nuclear Medicine, Zwolle (Netherlands); Ottervanger, Jan Paul; Timmer, Jorik R. [Isala klinieken, Department of Cardiology, Zwolle (Netherlands); Knollema, Siert; Reiffers, Stoffer; Oostdijk, Ad H.J.; Jager, Pieter L. [Isala klinieken, Department of Nuclear Medicine, Zwolle (Netherlands); Boer, Menko-Jan de [University Medical Centre Nijmegen, Department of Cardiology, Nijmegen (Netherlands)

    2014-05-15

    Recently introduced ultrafast cardiac SPECT cameras with cadmium zinc telluride-based (CZT) detectors may provide superior image quality allowing faster acquisition with reduced radiation doses. Although the level of concordance between conventional SPECT and invasive fractional flow reserve (FFR) measurement has been studied, that between FFR and CZT-based SPECT is not yet known. Therefore, we aimed to assess the level of concordance between CZT SPECT and FFR in a large patient group with stable coronary artery disease. Both invasive FFR and myocardial perfusion imaging with a CZT-based SPECT camera, using Tc-tetrofosmin as tracer, were performed in 100 patients with stable angina and intermediate grade stenosis on invasive coronary angiography. A cut-off value of <0.75 was used to define abnormal FFR. The mean age of the patients was 64 ± 11 years, and 64 % were men. SPECT demonstrated ischaemia in 31 % of the patients, and 20 % had FFR <0.75. The concordance between CZT SPECT and FFR was 73 % on a per-patient basis and 79 % on a per-vessel basis. Discordant findings were more often seen in older patients and were mainly (19 %) the result of ischaemic SPECT findings in patients with FFR ≥0.75, whereas only 8 % had an abnormal FFR without ischaemia as demonstrated by CZT SPECT. Only 20 - 30 % of patients with intermediate coronary stenoses had significant ischaemia as assessed by CZT SPECT or invasive FFR. CZT SPECT showed a modest degree of concordance with FFR, which is comparable with previous results with conventional SPECT. Further investigations are particularly necessary in patients with normal SPECT and abnormal FFR, especially to determine whether these patients should undergo revascularization. (orig.)

  17. The energetic impact of small Cd{sub x}Te{sub y} clusters on Cadmium Telluride

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Miao, E-mail: M.Yu2@lboro.ac.uk; Kenny, Steven D., E-mail: S.D.Kenny@lboro.ac.uk

    2015-06-01

    Cadmium Telluride (CdTe) is an excellent material for low-cost, high efficiency thin film solar cells. It is important to do research on how these defects are formed during the growth process, since defects lower the efficiency of solar cells. In this work we use computer simulation to predict the growth of a sputter deposited CdTe thin film. Single deposition tests have been performed, to study the behaviour of deposited clusters under different conditions. We deposit a Cd{sub x}Te{sub y} (x,y = 0,1) cluster onto the (100) and (111) Cd and Te terminated surfaces with energies ranging from 1 to 40 eV. More than 1000 simulations have been performed for each of these cases so as to sample the possible deposition positions and to collect sufficient statistics. The results show that Cd atoms are more readily sputtered from the surface than Te atoms and the sticking probability is higher on Te terminated surfaces than Cd terminated surfaces. They also show that increasing the deposition energy typically leads to an increase in the number of atoms sputtered from the system and tends to decrease the number of atoms that sit on or in the surface layer, whilst increasing the number of interstitials observed. - Highlights: • Deposition of Cd, Te and CdTe particles on (100) and (111) Cd and Te surfaces • Cd atoms are more readily sputtered from the surface than Te atoms. • The Te terminated surfaces have a higher sticking probability than the Cd ones. • Higher impact energies imply more sputtered atoms from the surface.

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

    Energy Technology Data Exchange (ETDEWEB)

    Rohatgi, A.; Summers, C.J.; Erbil, A.; Sudharsanan, R.; Ringel, S. (Georgia Inst. of Tech., Atlanta, GA (USA). 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.

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

    Science.gov (United States)

    Rohatgi, A.; Summers, C. J.; Erbil, A.; Sudharsanan, R.; Ringel, S.

    1990-10-01

    Polycrystalline Cd(1-x)Zn(x)Te and Cd(1-x)Mn(x)Te films with a band gap of 1.7 eV were successfully grown on glass/SnO2/CdS substrates by molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD), respectively. Polycrystalline Cd(1-x)Zn(x)Te films grown by MBE resulted in uniform composition and sharp interfaces. However, polycrystalline Cd(1-x)Mn(x)Te films grown by MOCVD showed nonuniform compositions and evidence of manganese accumulation at the Cd(1-x)Mn(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 percent. MBE-grown CdTe cells also produced 8 to 9 percent efficiencies. The standard CdTe process was not optimum for ternary films and resulted in a decrease in the band gap. Recent results indicate that CdCl2 + ZnCl2 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.

  20. Polycrystalline thin film photovoltaic technology

    Energy Technology Data Exchange (ETDEWEB)

    Ullal, H.S.; Zweibel, K.; Mitchell, R.L.; Noufi, R.

    1991-03-01

    Low-cost, high-efficiency thin-film modules are an exciting photovoltaic technology option for generating cost-effective electricity in 1995 and beyond. In this paper we review the significant technical progress made in the following thin films: copper indium diselenide, cadmium telluride, and polycrystalline thin silicon films. Also, the recent US DOE/SERI initiative to commercialize these emerging technologies is discussed. 6 refs., 9 figs.

  1. Size and temperature dependence of the photoluminescence properties of NIR emitting ternary alloyed mercury cadmium telluride quantum dots

    Science.gov (United States)

    Jagtap, Amardeep M.; Chatterjee, Abhijit; Banerjee, Arup; Babu Pendyala, Naresh; Koteswara Rao, K. S. R.

    2016-04-01

    Exciton-phonon coupling and nonradiative relaxation processes have been investigated in near-infrared (NIR) emitting ternary alloyed mercury cadmium telluride (CdHgTe) quantum dots. Organically capped CdHgTe nanocrystals of sizes varying from 2.5-4.2 nm have been synthesized where emission is in the NIR region of 650-855 nm. Temperature-dependent (15-300 K) photoluminescence (PL) and the decay dynamics of PL at 300 K have been studied to understand the photophysical properties. The PL decay kinetics shows the transition from triexponential to biexponential on increasing the size of the quantom dots (QDs), informing the change in the distribution of the emitting states. The energy gap is found to be following the Varshni relation with a temperature coefficient of 2.1-2.8  ×  10-4 eV K-1. The strength of the electron-phonon coupling, which is reflected in the Huang and Rhys factor S, is found in the range of 1.17-1.68 for QDs with a size of 2.5-4.2 nm. The integrated PL intensity is nearly constant until 50 K, and slowly decreases up to 140 K, beyond which it decreases at a faster rate. The mechanism for PL quenching with temperature is attributed to the presence of nonradiative relaxation channels, where the excited carriers are thermally stimulated to the surface defect/trap states. At temperatures of different region (<140 K and 140-300 K), traps of low (13-25 meV) and high (65-140 meV) activation energies seem to be controlling the quenching of the PL emission. The broadening of emission linewidth is found to due to exciton-acoustic phonon scattering and exciton-longitudinal optical (LO) phonon coupling. The exciton-acoustic phonon scattering coefficient is found to be enhanced up to 55 μeV K-1 due to a stronger confinement effect. These findings give insight into understanding the photophysical properties of CdHgTe QDs and pave the way for their possible applications in the fields of NIR photodetectors and other optoelectronic devices.

  2. Determining energy production of CdTe photovoltaic system

    OpenAIRE

    Virtič, Peter; Šlamberger, Jan

    2015-01-01

    This paper presents a method for determining energy production of Cadmium-Telluride photovoltaic system, which has a different working performance than the most used Silicon photovoltaic systems. The main difference is sensitivity to the temperature and the solar irradiance. The CdTe cells are less sensitive to the temperature and in contrast to the Si Cells they have a higher efficiency at lower irradiance.

  3. Thin film cadmium telluride photovoltaic cells. Annual subcontract report, 1 November 1991--31 October 1992

    Energy Technology Data Exchange (ETDEWEB)

    Compaan, C.D.; Bohn, R.G. [Toledo Univ., OH (United States)

    1993-10-01

    This report describes work to develop and optimize radio-frequency (RF) sputtering and laser-driven physical vapor deposition (LDPVD) for CdTe-based thin-film solar cells. Both of these techniques are vacuum-based and share several other common physical principles. However, they differ somewhat in the typical kinetic energies of Cd, Te, and S that impact on the growth surface. The values of several processing parameters-optimized with the LDPVD technique-were taken as starting values for the RF sputtering method. We completed an initial optimization of the sputtering parameters for the CdTe growth and also successfully sputtered CdS for the first time. In addition, we successfully fabricated what we believe are the first CdS/CdTe cells in which RF sputtering was used for both CdS and CdTe layers. We achieved an all-LDPVD ell with an air mass (AM) 1.5 efficiency of 10.5% and an all-RF-sputtered cell with AM 1.5 efficiency of 10.4%, as tested by NREL.

  4. Thin film cadmium telluride photovoltaic cells. Annual subcontract report, 23 July 1990--31 October 1991

    Energy Technology Data Exchange (ETDEWEB)

    Compaan, A.; Bohn, R. [Toledo Univ., OH (United States)

    1992-04-01

    This report describes research to develop to vacuum-based growth techniques for CdTe thin-film solar cells: (1) laser-driven physical vapor deposition (LDPVD) and (2) radio-frequency (rf) sputtering. The LDPVD process was successfully used to deposit thin films of CdS, CdTe, and CdCl{sub 2}, as well as related alloys and doped semiconductor materials. The laser-driven deposition process readily permits the use of several target materials in the same vacuum chamber and, thus, complete solar cell structures were fabricated on SnO{sub 2}-coated glass using LDPVD. The rf sputtering process for film growth became operational, and progress was made in implementing it. Time was also devoted to enhancing or implementing a variety of film characterization systems and device testing facilities. A new system for transient spectroscopy on the ablation plume provided important new information on the physical mechanisms of LDPVD. The measurements show that, e.g., Cd is predominantly in the neutral atomic state in the plume but with a fraction that is highly excited internally ({ge} 6 eV), and that the typical neutral Cd translational kinetic energies perpendicular to the target are 20 eV and greater. 19 refs.

  5. Material and detector properties of cadmium manganese telluride (Cd1-xMnxTe) crystals grown by the modified floating-zone method

    Science.gov (United States)

    Hossain, A.; Gu, G. D.; Bolotnikov, A. E.; Camarda, G. S.; Cui, Y.; Roy, U. N.; Yang, G.; Liu, T.; Zhong, R.; Schneeloch, J.; James, R. B.

    2015-06-01

    We demonstrated the material- and radiation-detection properties of cadmium manganese telluride (Cd1-xMnxTe; x=0.06), a wide-band-gap semiconductor crystal grown by the modified floating-zone method. We investigated the presence of various bulk defects, such as Te inclusions, twins, and dislocations of several as-grown indium-doped Cd1-xMnxTe crystals using different techniques, viz., IR transmission microscopy, and chemical etching. We then fabricated four planar detectors from selected CdMnTe crystals, characterized their electrical properties, and tested their performance as room-temperature X- and gamma-ray detectors. Our experimental results show that CMT crystals grown by the modified floating zone method apparently are free from Te inclusions. However, we still need to optimize our growth parameters to attain high-resistivity, large-volume single-crystal CdMnTe.

  6. Efficient charge transfer and field-induced tunneling transport in hybrid composite device of organic semiconductor and cadmium telluride quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Varade, Vaibhav, E-mail: vaibhav.tvarade@gmail.com; Jagtap, Amardeep M.; Koteswara Rao, K. S. R.; Ramesh, K. P.; Menon, R. [Department of Physics, Indian Institute of Science, Bangalore 560012 (India); Anjaneyulu, P. [Department of Physics, Gitam University, Hyderabad 502329 (India)

    2015-06-07

    Temperature and photo-dependent current–voltage characteristics are investigated in thin film devices of a hybrid-composite comprising of organic semiconductor poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) and cadmium telluride quantum dots (CdTe QDs). A detailed study of the charge injection mechanism in ITO/PEDOT:PSS-CdTe QDs/Al device exhibits a transition from direct tunneling to Fowler–Nordheim tunneling with increasing electric field due to formation of high barrier at the QD interface. In addition, the hybrid-composite exhibits a huge photoluminescence quenching compared to aboriginal CdTe QDs and high increment in photoconductivity (∼ 400%), which is attributed to the charge transfer phenomena. The effective barrier height (Φ{sub B} ≈ 0.68 eV) is estimated from the transition voltage and the possible origin of its variation with temperature and photo-illumination is discussed.

  7. Investigation of the Internal Electric Field in Cadmium Zinc Telluride Detectors Using the Pockels Effect and the Analysis of Charge Transients

    Science.gov (United States)

    Groza, Michael; Krawczynski, Henic; Garson, Alfred, III; Martin, Jerrad W.; Lee, Kuen; Li, Qiang; Beilicke, Matthias; Cui, Yunlong; Buliga, Vladimir; Guo, Mingsheng; Coca, Constantine; Burger, Arnold

    2010-01-01

    The Pockels electro-optic effect can be used to investigate the internal electric field in cadmium zinc telluride (CZT) single crystals that are used to fabricate room temperature x and gamma radiation detectors. An agreement is found between the electric field mapping obtained from Pockels effect images and the measurements of charge transients generated by alpha particles. The Pockels effect images of a CZT detector along two mutually perpendicular directions are used to optimize the detector response in a dual anode configuration, a device in which the symmetry of the internal electric field with respect to the anode strips is of critical importance. The Pockels effect is also used to map the electric field in a CZT detector with dual anodes and an attempt is made to find a correlation with the simulated electric potential in such detectors. Finally, the stress-induced birefringence effects seen in the Pockels images are presented and discussed.

  8. Efficient charge transfer and field-induced tunneling transport in hybrid composite device of organic semiconductor and cadmium telluride quantum dots

    International Nuclear Information System (INIS)

    Temperature and photo-dependent current–voltage characteristics are investigated in thin film devices of a hybrid-composite comprising of organic semiconductor poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) and cadmium telluride quantum dots (CdTe QDs). A detailed study of the charge injection mechanism in ITO/PEDOT:PSS-CdTe QDs/Al device exhibits a transition from direct tunneling to Fowler–Nordheim tunneling with increasing electric field due to formation of high barrier at the QD interface. In addition, the hybrid-composite exhibits a huge photoluminescence quenching compared to aboriginal CdTe QDs and high increment in photoconductivity (∼ 400%), which is attributed to the charge transfer phenomena. The effective barrier height (ΦB ≈ 0.68 eV) is estimated from the transition voltage and the possible origin of its variation with temperature and photo-illumination is discussed

  9. Cadmium telluride module development

    Energy Technology Data Exchange (ETDEWEB)

    Albrigth, S.P.; Chamberlin, R.R.; Jordan, J.F. (Photon Energy, Inc., El Paso, TX (USA))

    1991-05-01

    Efficiencies of up to 12.3% have been achieved on small devices. It is expected that 14% efficiency will be exceeded on small devices by improving the fill factors on the present devices in the reasonably near future. Efficiencies in the range 16%-18% are expected to be achieved in the longer term. Modules of 6 W, approximately 929 cm{sup 2} in area with an active area efficiency of over 8% (aperture efficiency of 7.3%) have been achieved. The feasibility of producing 4 ft{sup 2} modules of CdS/CdTe has been shown and requires further efforts in order to realize the overall potentials. The structural integrity of the encapsulation design has been studied by thermal cycling and outdoor life testing. Submodules have been life tested for over 270 days with no observable degradation by the SERI Outdoor Reliability and Life Testing Laboratory. In addition to further optimization of materials and device structure, module output in the future will be increased by an improvement in the uniformity of the deposition process, and by minimizing the loss of active area due to cell division interconnections. Module output is expected to attain 135 W m{sup -2} in the mid 1990s and over 150 W m{sup -2} in the long term. (orig.).

  10. Effects of annealing conditions of electrodes on the photovoltaic properties of sintered cadmium sulfide/cadmium telluride solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Kim, C.S.; Im, H.B. (Korea Advanced Inst. of Science, Seoul (Republic of Korea). Dept. of Materials Science)

    1990-01-01

    Polycrystalline n-CdS/p-CdTe solar cells with a commercial carbon paint on the p-CdTe layer and an In- Ag paint on the n-CdS layer were fabricated by a coating and sintering method. Electrical properties of the conducting paints and solar cell parameters of the heterojunction solar cells were investigated as a function of electrode annealing conditions. The sintered CdS/CdTe solar cells whose electrode contacts were annealed at 350{degrees}C for 10 min in nitrogen showed maximum values of short-circuit current density, fill factor, and solar efficiency. Commercial carbon and silver paints can be used as electrodes to fabricate sintered CdS/CdTe solar cells with efficiency over 10%.

  11. Photovoltaic properties of cadmium selenide–titanyl phthalocyanine planar heterojunction devices

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • CdSe/TiOPc cells harvest light practically in the whole visible range. • Two mechanism of photogeneration of charge carriers are distinguished. • Monomolecular recombination of free charge carriers is predominant. • Relatively high fill factor under monochromatic illumination was obtained. • Thickness optimization is required for the improvement of current density. - Abstract: Photovoltaic phenomenon taking place in cadmium selenide (CdSe)/titanyl phthalocyanine (TiOPc) planar heterojunction devices is described. Mechanisms of free charge carrier generation and their recombination in the dark and under illumination are analyzed, chosen photovoltaic parameters are presented

  12. Photovoltaics

    Science.gov (United States)

    Seippel, R. G.

    This book attempts to provide the reader with a cursory look at solar energy from a quarry of quartz to a sophisticated solar system. The progression of the theories of light is discussed along with the progression of photoelectricity, light rays, the optical spectrum, light reception, photodetection, aspects of photometry and radiometry, preferred terms in radiometric measurement, semiconductor physics, and light energy availability. Other subjects explored are related to manufacturing processes, photovoltaic materials, crystal growing, slicing techniques, wafer finishing, solar cell fabrication, photovoltaic cell types, concentrators, module fabrication, problems of quality assurance, photovoltaic systems, and the photovoltaics hierarchy. Attention is given to the polycrystalline cell, insulator cells, cadmium sulfide cells, amorphous silicon cells, an electrochemical cell, and the low-cost solar array project.

  13. Characterization of a sub-assembly of 3D position sensitive cadmium zinc telluride detectors and electronics from a sub-millimeter resolution PET system

    Science.gov (United States)

    Abbaszadeh, Shiva; Gu, Yi; Reynolds, Paul D.; Levin, Craig S.

    2016-09-01

    Cadmium zinc telluride (CZT) offers key advantages for small animal positron emission tomography (PET), including high spatial and energy resolution and simple metal deposition for fabrication of very small pixel arrays. Previous studies have investigated the intrinsic spatial, energy, and timing resolution of an individual sub-millimeter resolution CZT detector. In this work we present the first characterization results of a system of these detectors. The 3D position sensitive dual-CZT detector module and readout electronics developed in our lab was scaled up to complete a significant portion of the final PET system. This sub-system was configured as two opposing detection panels containing a total of twelve 40~\\text{mm}× 40~\\text{mm}× 5 mm monolithic CZT crystals for proof of concept. System-level characterization studies, including optimizing the trigger threshold of each channel’s comparators, were performed. 68Ge and 137Cs radioactive isotopes were used to characterize the energy resolution of all 468 anode channels in the sub-system. The mean measured global 511 keV photopeak energy resolution over all anodes was found to be 7.35+/- 1.75 % FWHM after correction for photon interaction depth-dependent signal variation. The measured global time resolution was 37 ns FWHM, a parameter to be further optimized, and the intrinsic spatial resolution was 0.76 mm FWHM.

  14. Simulation and experimental characterization of the point spread function, pixel saturation, and blooming of a mercury cadmium telluride focal plane array.

    Science.gov (United States)

    Soehnel, Grant; Tanbakuchi, Anthony

    2012-11-20

    A custom IR spot scanning experiment was constructed to project subpixel spots on a mercury cadmium telluride focal plane array (FPA). The hardware consists of an FPA in a liquid nitrogen cooled Dewar, high precision motorized stages, a custom aspheric lens, and a 1.55 and 3.39 μm laser source. By controlling the position and intensity of the spot, characterizations of cross talk, saturation, blooming, and (indirectly) the minority carrier lifetime were performed. In addition, a Monte-Carlo-based charge diffusion model was developed to validate experimental data and make predictions. Results show very good agreement between the model and experimental data. Parameters such as wavelength, reverse bias, and operating temperature were found to have little effect on pixel crosstalk in the absorber layer of the detector. Saturation characterizations show that these FPAs, which do not have antiblooming circuitry, exhibit an increase in cross talk due to blooming at ∼39% beyond the flux required for analog saturation. PMID:23207309

  15. Rapid long-wave infrared laser-induced breakdown spectroscopy measurements using a mercury-cadmium-telluride linear array detection system.

    Science.gov (United States)

    Yang, Clayton S-C; Brown, Eiei; Kumi-Barimah, Eric; Hommerich, Uwe; Jin, Feng; Jia, Yingqing; Trivedi, Sudhir; D'souza, Arvind I; Decuir, Eric A; Wijewarnasuriya, Priyalal S; Samuels, Alan C

    2015-11-20

    In this work, we develop a mercury-cadmium-telluride linear array detection system that is capable of rapidly capturing (∼1-5  s) a broad spectrum of atomic and molecular laser-induced breakdown spectroscopy (LIBS) emissions in the long-wave infrared (LWIR) region (∼5.6-10  μm). Similar to the conventional UV-Vis LIBS, a broadband emission spectrum of condensed phase samples covering the whole 5.6-10 μm region can be acquired from just a single laser-induced microplasma or averaging a few single laser-induced microplasmas. Atomic and molecular signature emission spectra of solid inorganic and organic tablets and thin liquid films deposited on a rough asphalt surface are observed. This setup is capable of rapidly probing samples "as is" without the need of elaborate sample preparation and also offers the possibility of a simultaneous UV-Vis and LWIR LIBS measurement.

  16. High-efficiency cadmium and zinc telluride based thin-film solar cells: Annual report, June 1, 1987--May 31, 1988

    Energy Technology Data Exchange (ETDEWEB)

    Rohatgi, A.; Summers, C.J.; Erbil, A.; Sudharsanan, R.; Ringel. S.

    1989-04-01

    This report contains results of research on high-efficiency cadmium and zinc telluride based thin-film solar cells from June 1987 to May 1988. CdTe and CdZnTe and CdTe and CdMnTe films were grown on CdS/SnO/sub 2//glass substrates by molecular beam epitaxy and metal-organic chemical vapor deposition, respectively. As-grown films were characterized by x-ray diffraction, surface photovoltage spectroscopy, and infrared, Raman, and Auger electron spectroscopy, among others, for composition, bulk uniformity, thickness, and film and interface quality. Single-crystal films were grown simultaneously to understand the growth conditions of the polycrystalline films. Cell efficiencies ranging from 6.0% to 6.7% were achieved with the Cd/sub 0.95/Mn/sub 0.05/Te film employing the glass/SnO/sub 2//CdS/CdMnTe/ZnTe/Au front-wall solar cell structure. Cells fabricated by using CdZnTe films yielded efficiencies from 3.0% to 3.6%. 12 refs., 32 figs., 7 tabs.

  17. Nuclear myocardial perfusion imaging with a novel cadmium-zinc-telluride detector SPECT/CT device: first validation versus invasive coronary angiography

    International Nuclear Information System (INIS)

    We evaluated the diagnostic accuracy of attenuation corrected nuclear myocardial perfusion imaging (MPI) with a novel hybrid single photon emission computed tomography (SPECT)/CT device consisting of an ultrafast dedicated cardiac gamma camera with cadmium-zinc-telluride (CZT) solid-state semiconductor detectors integrated onto a multislice CT scanner to detect coronary artery disease (CAD). Invasive coronary angiography served as the standard of reference. The study population included 66 patients (79% men; mean age 63 ± 11 years) who underwent 1-day 99mTc-tetrofosmin pharmacological stress/rest examination and angiography within 3 months. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) as well as accuracy of the CT X-ray based attenuation corrected CZT MPI for detection of CAD (≥50% luminal narrowing) was calculated on a per-patient basis. The prevalence of angiographic CAD in the study population was 82%. Sensitivity, specificity, PPV, NPV and accuracy were 87, 67, 92, 53 and 83%, respectively. In this first report on CZT SPECT/CT MPI comparison versus angiography we confirm a high accuracy for detection of angiographically documented CAD. (orig.)

  18. Apoptosis Induction and Imaging of Cadmium-Telluride Quantum Dots with Wogonin in Multidrug-Resistant Leukemia K562/A02 Cell.

    Science.gov (United States)

    Huang, Bin; Liu, Hongyi; Huang, Dongliang; Mao, Xuhua; Hu, Xianyun; Jiang, Caiyun; Pu, Maomao; Zhang, Gen; Zeng, Xin

    2016-03-01

    Wogonin (5,7-dihydroxy-8-methoxyflavone) is one of the active components of flavonoids isolated from Scutellariae radix and possesses antitumor effect against leukemia. Cadmium-telluride quantum dots (CdTe-QDs) are a kind of nanoparticles with great potential in functioning as an efficient drug delivery vector in biomedical research. In this study, we investigated the synergistic effect of CdTe-QDs with Wogonin on the induction of apoptosis using drug-resistant human leukemia KA cells. Flow cytometry analysis, assay of morphology under electron microscope, quantitative analysis of tumor volume and micro-CT imaging demonstrated that compared with that by pure CdTe-QDs or wogonin, the apoptosis rate increased sharply when treated wirh CdTe-QDs together with wogonin on KA cells. These results proved that the nanocomposites readily overcame the barrier of drug-resistance and provoked cell apoptosis in vitro and in vivo by facilitating the interaction between wogonin and KA cells. As known to all, it is an inevitable tendency that new effective therapies will take the place of conventional chemotherapy and radiotherapy presenting significant disadvantages. According to this article, CdTe-QD combined with wogonin is a possible alternative for some cancer treatments. PMID:27455661

  19. First principles phase transition, elastic properties and electronic structure calculations for cadmium telluride under induced pressure: density functional theory, LDA, GGA and modified Becke-Johnson potential

    Science.gov (United States)

    Kabita, Kh; Maibam, Jameson; Indrajit Sharma, B.; Brojen Singh, R. K.; Thapa, R. K.

    2016-01-01

    We report first principles phase transition, elastic properties and electronic structure for cadmium telluride (CdTe) under induced pressure in the light of density functional theory using the local density approximation (LDA), generalised gradient approximation (GGA) and modified Becke-Johnson (mBJ) potential. The structural phase transition of CdTe from a zinc blende (ZB) to a rock salt (RS) structure within the LDA calculation is 2.2 GPa while that within GGA is found to be at 4 GPa pressure with a volume collapse of 20.9%. The elastic constants and parameters (Zener anisotropy factor, Shear modulus, Poisson’s ratio, Young’s modulus, Kleinmann parameter and Debye’s temperature) of CdTe at different pressures of both the phases have been calculated. The band diagram of the CdTe ZB structure shows a direct band gap of 1.46 eV as predicted by mBJ calculation which gives better results in close agreement with experimental results as compared to LDA and GGA. An increase in the band gap of the CdTe ZB phase is predicted under induced pressure while the metallic nature is retained in the CdTe RS phase.

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

    Science.gov (United States)

    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. PMID:25007593

  1. Studies on focal alveolar bone healing with technetium (Tc)-99m labeled methylene diphosphonate and gold-collimated cadmium telluride probe

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchimochi, M.; Hosain, F.; Engelke, W.; Zeichner, S.J.; Ruttimann, U.E.; Webber, R.L. (National Institute of Dental Research, Bethesda, MD (USA))

    1991-01-01

    The benefit of using a collimator for a miniaturized cadmium telluride probe was evaluated by monitoring the bone-healing processes for 13 weeks after the induction of small iatrogenic alveolar bone lesions in one side of the mandible in beagles. Technetium (Tc)-99m labeled methylene diphosphonate (200 to 300 MBq, 5.1 to 8.1 mCi, in a solution of 0.5 to 1 ml, intravenously) was used as a bone-seeking radiopharmaceutical. The radioactivity over the bone lesion (L) and the contralateral normal site (C) in the mandible were measured between 1.5 and 2 hours after injection of the tracer, and the activity ratio L/C served as an index of relative bone uptake. A study of six dogs revealed that the healing response to a hemispheric bone defect of 2 mm diameter in the cortical bone could not be detected by an uncollimated probe, and in a repeated study in two dogs the use of a gold collimator (5 mm in diameter, 5 mm in length) did not increase the L/C ratio significantly. A second study in six dogs with 5 mm lesions showed that although systematic trends in the time courses of the L/C ratio obtained both with and without the collimator could be demonstrated, the L/C ratio of collimated versus uncollimated measurements was significantly (p less than 0.005) increased. In three of the latter six dogs, abscesses developed after 9 weeks, leading to a second increase (p less than 0.05) of the L/C ratio with collimation compared with the noninflammation group; without collimation no significant (p greater than 0.15) difference between the two groups could be demonstrated.

  2. Controlled cadmium telluride thin films for solar cell applications. Second quarterly report, September 1-December 1, 1980

    Energy Technology Data Exchange (ETDEWEB)

    Das, M. B.; Krishnaswamy, S. V.

    1981-01-01

    A thermal annealing procedure to improve the photovoltaic and other electrical characteristics of CdTe sputtered films doped with In is described. For an understanding of the characteristics of these films, SEM, Auger electron spectroscopy and scanning ellipsometry analyses have been carried out. Dark and illuminated I/V characteristics and capacitance and conductance vs. frequency behavior of In doped CdTe Schottky barrier diodes based on Cr and Ni substrates indicate that thermal annealing is an effective means of reducing the trap concentrations on these films that can lead to a significant improvement of the quality of sputtered films for solar cell applications.

  3. The performance of a combined solar photovoltaic (PV) and thermoelectric generator (TEG) system

    OpenAIRE

    Bjørk, R.; Nielsen, K K

    2015-01-01

    The performance of a combined solar photovoltaic (PV) and thermoelectric generator (TEG) system is examined using an analytical model for four different types of commercial PVs and a commercial bismuth telluride TEG. The TEG is applied directly on the back of the PV, so that the two devices have the same temperature. The PVs considered are crystalline Si (c-Si), amorphous Si (a-Si), copper indium gallium (di)selenide (CIGS) and cadmium telluride (CdTe) cells. The degradation of PV performance...

  4. Effect of Annealing On Thin Film Fabrication of Cadmium Zinc Telluride by Single-R.F. Magnetron Sputtering Unit

    Directory of Open Access Journals (Sweden)

    Dr. Monisha Chakraborty A,

    2014-01-01

    Full Text Available In this work, formation of Cd1-xZnxTe thin films under various annealing-environments, created by layer by layer deposition of individual CdTe and ZnTe targets from a Single-R.F. Magnetron Sputtering unit is investigated. Structural and optical characterization results show that Vacuum Annealing is the best suitable for the formation of better Cd1-xZnxTe XRD peaks of higher intensities in comparison to Argon or Nitrogen-Annealing, for a bi-layered deposited CdTe and ZnTe film on glass substrate. The crystallography of the Cd1-xZnxTe films formed appeared to be either Cubic or Rhombohedral type. Also, it has been noticed, that the more inert the annealing-environment is, the lesser is the heat loss by the film-substrate and this results in better fusing of the deposited particles to move more from the poly-crystalline to the mono-crystalline structure. Also higher inert environment causes more Cadmium evaporation and this consequently drives the lattice-constant and the band-gap energy of the formed Cd1-xZnxTe thin film to move from the CdTe side to the ZnTe side. The method developed here with proper annealing ambiance for Cd1-xZnxTe fabrication can be implemented in laboratories lacking in Co-Sputtering machine.

  5. Characterization of nanocrystalline cadmium telluride thin films grown by successive ionic layer adsorption and reaction (SILAR) method

    Indian Academy of Sciences (India)

    A U Ubale; R J Dhokne; P S Chikhlikar; V S Sangawar; D K Kulkarni

    2006-04-01

    Structural, electrical and optical characteristics of CdTe thin films prepared by a chemical deposition method, successive ionic layer adsorption and reaction (SILAR), are described. For deposition of CdTe thin films, cadmium acetate was used as cationic and sodium tellurite as anionic precursor in aqueous medium. In this process hydrazine hydrate is used as reducing agent and NH4OH as the catalytic for the decomposition of hydrazine. By conducting several trials optimization of the adsorption, reaction and rinsing time duration for CdTe thin film deposition was done. In this paper the structural, optical and electrical properties of CdTe film are reported. The XRD pattern shows that films are nanocrystalline in nature. The resistivity is found to be of the order of 4.11 × 103 -cm at 523 K temperature with an activation energy of ∼ 0.2 eV. The optical absorption studies show that films have direct band gap (1.41 eV).

  6. Polycrystalline thin film cadmium telluride solar cells fabricated by electrodeposition. Annual technical report, 20 March 1995--19 March 1996

    Energy Technology Data Exchange (ETDEWEB)

    Trefny, J U; Mao, D [Colorado School of Mines, Golden, CO (United States)

    1997-04-01

    The objective of this project is to develop improved processes for fabricating CdTe/CdS polycrystalline thin-film solar cells. Researchers used electrodeposition to form CdTe; electrodeposition is a non-vacuum, low-cost technique that is attractive for economic, large-scale production. During the past year, research and development efforts focused on several steps that are most critical to the fabricating high-efficiency CdTe solar cells. These include the optimization of the CdTe electrodeposition process, the effect of pretreatment of CdS substrates, the post-deposition annealing of CdTe, and back-contact formation using Cu-doped ZnTe. Systematic investigations of these processing steps have led to a better understanding and improved performance of the CdTe-based cells. Researchers studied the structural properties of chemical-bath-deposited CdS thin films and their growth mechanisms by investigating CdS samples prepared at different deposition times; investigated the effect of CdCl{sub 2} treatment of CdS films on the photovoltaic performance of CdTe solar cells; studied Cu-doped ZnTe as a promising material for forming stable, low-resistance contacts to the p-type CdTe; and investigated the effect of CdTe and CdS thickness on the photovoltaic performance of the resulting cells. As a result of their systematic investigation and optimization of the processing conditions, researchers improved the efficiency of CdTe/CdS cells using ZnTe back-contact and electrodeposited CdTe. The best CdTe/CdS cell exhibited a V{sub oc} of 0.778 V, a J{sub sc} of 22.4 mA/cm{sup 2}, a FF of 74%, and an efficiency of 12.9% (verified at NREL). In terms of individual parameters, researchers obtained a V{sub oc} over 0.8 V and a FF of 76% on other cells.

  7. Time-dependent toxicity of cadmium telluride quantum dots on liver and kidneys in mice: histopathological changes with elevated free cadmium ions and hydroxyl radicals

    Directory of Open Access Journals (Sweden)

    Wang M

    2016-05-01

    Full Text Available Mengmeng Wang,1,2,* Jilong Wang,1,2,* Hubo Sun,1,2 Sihai Han,3 Shuai Feng,1 Lu Shi,1 Peijun Meng,1,2 Jiayi Li,1,2 Peili Huang,1,2 Zhiwei Sun1,2 1Department of Toxicology and Sanitary Chemistry, School of Public Health, Capital Medical University, 2Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing, 3College of Food and Bioengineering, Henan University of Science and Technology, Luoyang, People’s Republic of China *These authors contributed equally to this work Abstract: A complete understanding of the toxicological behavior of quantum dots (QDs in vivo is of great importance and a prerequisite for their application in humans. In contrast with the numerous cytotoxicity studies investigating QDs, only a few in vivo studies of QDs have been reported, and the issue remains controversial. Our study aimed to understand QD-mediated toxicity across different time points and to explore the roles of free cadmium ions (Cd2+ and hydroxyl radicals (·OH in tissue damage. Male ICR mice were administered a single intravenous dose (1.5 µmol/kg of CdTe QDs, and liver and kidney function and morphology were subsequently examined at 1, 7, 14, and 28 days. Furthermore, ·OH production in the tissue was quantified by trapping ·OH with salicylic acid (SA as 2,3-dihydroxybenzoic acid (DHBA and detecting it using a high-performance liquid chromatography fluorescence method. We used the induction of tissue metallothionein levels and 2,3-DHBA:SA ratios as markers for elevated Cd2+ from the degradation of QDs and ·OH generation in the tissue, respectively. Our experimental results revealed that the QD-induced histopathological changes were time-dependent with elevated Cd2+ and ·OH, and could recover after a period of time. The Cd2+ and ·OH exhibited delayed effects in terms of histopathological abnormalities. Histological assessments performed at multiple time points might facilitate the evaluation of the biological safety of

  8. The state of the art of thin-film photovoltaics

    International Nuclear Information System (INIS)

    Thin-film photovoltaic technologies, based on materials such as amorphous or polycrystalline silicon, copper indium diselenide, cadmium telluride, and gallium arsenide, offer the potential for significantly reducing the cost of electricity generated by photovoltaics. The significant progress in the technologies, from the laboratory to the marketplace, is reviewed. The common concerns and questions raised about thin films are addressed. Based on the progress to date and the potential of these technologies, along with continuing investments by the private sector to commercialize the technologies, one can conclude that thin-film PV will provide a competitive alternative for large-scale power generation in the future

  9. Efficient and ultrafast formation of long-lived charge-transfer exciton state in atomically thin cadmium selenide/cadmium telluride type-II heteronanosheets.

    Science.gov (United States)

    Wu, Kaifeng; Li, Qiuyang; Jia, Yanyan; McBride, James R; Xie, Zhao-xiong; Lian, Tianquan

    2015-01-27

    Colloidal cadmium chalcogenide nanosheets with atomically precise thickness of a few atomic layers and size of 10-100 nm are two-dimensional (2D) quantum well materials with strong and precise quantum confinement in the thickness direction. Despite their many advantageous properties, excitons in these and other 2D metal chalcogenide materials are short-lived due to large radiative and nonradiative recombination rates, hindering their applications as light harvesting and charge separation/transport materials for solar energy conversion. We showed that these problems could be overcome in type-II CdSe/CdTe core/crown heteronanosheets (with CdTe crown laterally extending on the CdSe nanosheet core). Photoluminesence excitation measurement revealed that nearly all excitons generated in the CdSe and CdTe domains localized to the CdSe/CdTe interface to form long-lived charge transfer excitons (with electrons in the CdSe domain and hole in the CdTe domain). By ultrafast transient absorption spectroscopy, we showed that the efficient exciton localization efficiency could be attributed to ultrafast exciton localization (0.64 ± 0.07 ps), which was facilitated by large in-plane exciton mobility in these 2D materials and competed effectively with exiton trapping at the CdSe or CdTe domains. The spatial separation of electrons and holes across the CdSe/CdTe heterojunction effectively suppressed radiative and nonradiative recombination processes, leading to a long-lived charge transfer exciton state with a half-life of ∼ 41.7 ± 2.5 ns, ∼ 30 times longer than core-only CdSe nanosheets. PMID:25548944

  10. Effect of Nanosized Tin Oxide Layer on the Efficiency of Photovoltaic Processes in Film Solar Cells Based on Cadmium Telluride

    Directory of Open Access Journals (Sweden)

    G.S. Khrypunov

    2015-03-01

    Full Text Available The influence of the thickness of the nanosized layer on the efficiency of photoelectric processes in solar cells (SC ITO / SnO2 / CdS / CdTe / Cu / Au formed on different substrates was investigated. For device structures formed on the glass substrates, the maximum efficiency of 11.4 % is achieved when thickness of the tin oxide layer is 80 nm. For flexible solar cells formed on a polyimide film, the maximum efficiency of 10.8 % is observed when thickness of the tin oxide layer is 50 nm. This paper discusses the physical mechanisms of the observed differences in efficiency.

  11. High-efficiency thin-film cadmium telluride photovoltaic cells. Annual subcontract report, January 20, 1995--January 19, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Compaan, A D; Bohn, R G; Contreras-Puente, G [Toledo Univ., OH (United States). Dept. of Physics and Astronomy

    1996-05-01

    This annual report covers the second year of a 3-year NREL subcontract with the University of Toledo that is focused on improvements in efficiency for radio frequency (rf)-sputtered CdS/CdTe solar cells. In earlier work supported by NREL, the University of Toledo established the viability of two new deposition methods for CdS/CdTe solar cells by fabricating cells with efficiencies greater than 10% at air mass (AM) 1.5 on soda lime glass for all-sputtered cells and also for all-laser-deposited cells. Most of the effort has been placed on radio frequency sputtering (RFS) because it was judged to be more economical and more easily scaled to large-area deposition. However, laser physical vapor deposition (LPVD) has remained the method of choice for the deposition of CdCl{sub 2} layers and also for the exploration of new materials such as the ternary alloys including CdS{sub x} Te{sub 1{minus}x} and dopants such as Cu in ZnTe.

  12. Thin film photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Zweibel, K; Ullal, H S

    1989-05-01

    Thin films are considered a potentially attractive technological approach to making cost-effective electricity by photovoltaics. Over the last twenty years, many have been investigated and some (cadmium telluride, copper indium diselenide, amorphous silicon) have become leading candidates for future large-scale commercialization. This paper surveys the past development of these key thin films and gives their status and future prospects. In all cases, significant progress toward cost-effective PV electricity has been made. If this progress continues, it appears that thin film PV could provide electricity that is competitive for summer daytime peaking power requirements by the middle of the 1990s; and electricity in a range that is competitive with fossil fuel costs (i.e., 6 cents/kilowatt-hour) should be available from PV around the turn of the century. 22 refs., 9 figs.

  13. High-throughput manufacturing of thin-film CdS/CdTe photovoltaic modules. Annual subcontract report, 16 September 1996--15 January 1998

    Energy Technology Data Exchange (ETDEWEB)

    Sandwisch, D.W. [Solar Cells, Inc., Toledo, OH (United States)

    1998-08-01

    Cadmium telluride (CdTe) is recognized as one of the leading materials for low-cost photovoltaic modules. Solar Cells, Inc., has developed this technology and is scaling its pilot production capabilities to a multi-megawatt level. The Photovoltaic Manufacturing Technology (PVMaT) subcontract supports these efforts. Activities during the third phase of the program concentrated on process development, equipment design and testing, quality assurance, ES and H programs, and large-scale next-generation coating-system prototype development. These efforts broadly addressed the issues of the manufacturing process for producing thin-film, monolithic CdS/CdTe photovoltaic modules.

  14. Semiconductor materials for solar photovoltaic cells

    CERN Document Server

    Wong-Ng, Winnie; Bhattacharya, Raghu

    2016-01-01

    This book reviews the current status of semiconductor materials for conversion of sunlight to electricity, and highlights advances in both basic science and manufacturing.  Photovoltaic (PV) solar electric technology will be a significant contributor to world energy supplies when reliable, efficient PV power products are manufactured in large volumes at low cost.  Expert chapters cover the full range of semiconductor materials for solar-to-electricity conversion, from crystalline silicon and amorphous silicon to cadmium telluride, copper indium gallium sulfide selenides, dye sensitized solar cells, organic solar cells, and environmentally friendly copper zinc tin sulfide selenides. The latest methods for synthesis and characterization of solar cell materials are described, together with techniques for measuring solar cell efficiency. Semiconductor Materials for Solar Photovoltaic Cells presents the current state of the art as well as key details about future strategies to increase the efficiency and reduce ...

  15. 133Xenon absorption into rubber-protected portable cadmium telluride (CdTe(Cl)) detectors invalidating the 133Xenon washout method for measurement of cutaneous and subcutaneous blood flow rates in man.

    Science.gov (United States)

    Sørensen, J L

    1991-01-01

    The importance of 133Xenon absorption into rubber detector caps during cutaneous and subcutaneous blood flow measurement was investigated in 46 experiments involving 38 persons. 133Xenon was administered atraumatically. Cutaneous and subcutaneous washout rates were registered by portable Cadmium Telluride detectors without rubber caps, with rubber caps, and with rubber caps with Mylar membranes interposed between the rubber and the tissue investigated. No difference in rate constants obtained by means of various detector types was detected. The accumulation of 133Xenon in the rubber caps was found to take place within the first few minutes after the detectors had been brought into position. The 133Xenon then diffused back into the tissue exhibiting a great variation regarding rate constants. The 133Xenon diffused form rubber into air and perfused tissue tracing a monoexponential course; and again the rate constants would vary considerably. No correlation was found between elimination rates obtained with detectors with and without 133Xenon polluted caps, and no way of correcting for the 133Xenon content in the rubber caps was found. Relative changes in rate constants could still be recognized, but absolute values were not obtainable. PMID:1789123

  16. Demonstration of enhanced iodine K-edge imaging using an energy-dispersive X-ray computed tomography system with a 25 mm/s-scan linear cadmium telluride detector and a single comparator

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Eiichi, E-mail: dresato@iwate-med.ac.jp [Department of Physics, Iwate Medical University, 2-1-1 Nishitokuta, Yahaba, Iwate 028-3694 (Japan); Oda, Yasuyuki [Department of Physics, Iwate Medical University, 2-1-1 Nishitokuta, Yahaba, Iwate 028-3694 (Japan); Abudurexiti, Abulajiang [Faculty of Software and Information Science, Iwate Prefectural University, 152-52 Sugo, Takizawa, Iwate 020-0193 (Japan); Hagiwara, Osahiko; Matsukiyo, Hiroshi; Osawa, Akihiro; Enomoto, Toshiyuki; Watanabe, Manabu; Kusachi, Shinya [3rd Department of Surgery, Toho University School of Medicine, 2-17-6 Ohashi, Meguro-ku, Tokyo 153-8515 (Japan); Sato, Shigehiro [Department of Microbiology, School of Medicine, Iwate Medical University, 19-1 Uchimaru, Morioka, Iwate 020-0023 (Japan); Ogawa, Akira [Department of Neurosurgery, School of Medicine, Iwate Medical University, 19-1 Uchimaru, Morioka, Iwate 020-0023 (Japan); Onagawa, Jun [Department of Electronics, Faculty of Engineering, Tohoku Gakuin University, 1-13-1 Chuo, Tagajo, Miyagi 985-8537 (Japan)

    2012-05-15

    An energy-dispersive (ED) X-ray computed tomography (CT) system is useful for carrying out monochromatic imaging. To perform enhanced iodine K-edge CT, we developed an oscillation linear cadmium telluride (CdTe) detector with a scan velocity of 25 mm/s and an energy resolution of 1.2 keV. CT is performed by repeated linear scans and rotations of an object. Penetrating X-ray photons from the object are detected by the CdTe detector, and event signals of X-ray photons are produced using charge-sensitive and shaping amplifiers. The lower photon energy is determined by a comparator device, and the maximum photon energy of 60 keV corresponds to the tube voltage. Rectangular-shaped comparator outputs are counted by a counter card. In the ED-CT, tube voltage and current were 60 kV and 0.30 mA, respectively, and X-ray intensity was 14.8 {mu}Gy/s at 1.0 m from the source at a tube voltage of 60 kV. Demonstration of enhanced iodine K-edge X-ray CT for cancer diagnosis was carried out by selecting photons with energies ranging from 34 to 60 keV. - Highlights: Black-Right-Pointing-Pointer We developed an energy-dispersive X-ray CT system with a 25 mm/s-scan CdTe detector. Black-Right-Pointing-Pointer CT is performed by repeated linear scans and rotations of an object. Black-Right-Pointing-Pointer Lower photon energy is determined by a comparator device. Black-Right-Pointing-Pointer Spatial resolutions were 0.5 Multiplication-Sign 0.5 mm{sup 2}. Black-Right-Pointing-Pointer Iodine K-edge CT was carried out by selecting photons from 34 to 60 keV.

  17. Bis(3-methyl-2-pyridyl)ditelluride and pyridyl tellurolate complexes of zinc, cadmium, mercury: Synthesis, characterization and their conversion to metal telluride nanoparticles.

    Science.gov (United States)

    Kedarnath, G; Jain, Vimal K; Wadawale, Amey; Dey, Gautam K

    2009-10-21

    Treatment of an acetonitrile solution of metal chloride with bis(3-methyl-2-pyridyl)ditelluride, [Te(2)(pyMe)(2)], in the same solvent yielded complexes of composition [MCl(2){Te(2)(pyMe)(2)}] (M = Zn or Cd) whereas reactions of [MCl(2)(tmeda)] with NaTepyR (R = H or Me) gave tellurolate complexes of the general formula [M(TepyR)(2)] (M = Cd or Hg). When the cadmium complex [Cd(Tepy)(2)] was crystallized in the presence of excess tmeda, [Cd(Tepy)(2)(tmeda)] was formed exclusively. These complexes were characterized by elemental analyses, uv-vis, (1)H NMR data. The crystal structures of [ZnCl(2){Te(2)(pyMe)(2)}] and [Cd(Tepy)(2)(tmeda)] were established by single crystal X-ray diffraction. In the former zinc is coordinated to nitrogen atoms of the pyridyl group, while in the latter the coordination environment around tetrahedral cadmium is defined by the two neutral nitrogen atoms of tmeda, and two pyridyl tellurolate ligands. Thermal behavior of some of these complexes was studied by thermogravimetric analysis. Pyrolysis of [M(Tepy)(2)] in a furnace or in coordinating solvents such as hexadecylamine/tri-n-octylphosphine oxide (HDA/TOPO) at 350 and 160 degrees C, respectively gave MTe nanoparticles, which were characterized by uv-vis, photoluminiscence, XRD, EDAX and TEM.

  18. Environmental benefits of parking-integrated photovoltaics: A 222kWp experience

    DEFF Research Database (Denmark)

    Serrano-Luján, Lucía; García-Valverde, Rafael; Espinosa, Nieves;

    2015-01-01

    The life cycle assessment of a grid-connected, parking integrated, 222kWp cadmium telluride photovoltaic system has been performed. The system was built at the University of Murcia and has been monitored for 2.5years (sampling data every 5min). The detailed material inventory, the energy embedded...... integration (in this case parking integration) have been quantified using a standard methodology for the calculation of several environmental parameters. Finally, the environmental benefits of renewable energy generation because of the savings of producing the same amount of electricity by the Spanish grid...

  19. Controlled cadmium telluride thin films for solar cell applications (emerging materials systems for solar cell applications). Quarterly progress report No. 3, October 9, 1979-January 8, 1980

    Energy Technology Data Exchange (ETDEWEB)

    Vedam, K; Das, M B; Krishnaswamy, S V

    1980-02-01

    The main emphasis during the third quarter of the program was on the improvement of the quality of sputtered films, their characterization and use in the fabrication of Schottky barrier type diodes and solar cell structures. Films prepared under different conditions and on different substrates were examined by SEM showing nodular growths under certain conditions. I-V, C-V and photovoltaic characteristics were measured on numerous samples based on n- and p-type films on Ni substrates having top metallization of either evaporated Au and Al. The n-type samples showed up to 200mV V/sub oc/ and small short-circuit currents. The characteristics observed are indicative of the presence of interfacial layer and surface states. Surface state's capacitance were measured on p-type samples metallized with Au.

  20. The performance of a combined solar photovoltaic (PV) and thermoelectric generator (TEG) system

    CERN Document Server

    Bjørk, R

    2015-01-01

    The performance of a combined solar photovoltaic (PV) and thermoelectric generator (TEG) system is examined using an analytical model for four different types of commercial PVs and a commercial bismuth telluride TEG. The TEG is applied directly on the back of the PV, so that the two devices have the same temperature. The PVs considered are crystalline Si (c-Si), amorphous Si (a-Si), copper indium gallium (di)selenide (CIGS) and cadmium telluride (CdTe) cells. The degradation of PV performance with temperature is shown to dominate the increase in power produced by the TEG, due to the low efficiency of the TEG. For c-Si, CIGS and CdTe PV cells the combined system produces a lower power and has a lower efficiency than the PV alone, whereas for an a-Si cell the total system performance may be slightly increased by the TEG.

  1. The performance of a combined solar photovoltaic (PV) and thermoelectric generator (TEG) system

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Nielsen, Kaspar Kirstein

    2015-01-01

    The performance of a combined solar photovoltaic (PV) and thermoelectric generator (TEG) system is examined using an analytical model for four different types of commercial PVs and a commercial bismuth telluride TEG. The TEG is applied directly on the back of the PV, so that the two devices have ...... efficiency of the TEG. For c-Si, CIGS and CdTe PV cells the combined system produces a lower power and has a lower efficiency than the PV alone, whereas for an a-Si cell the total system performance may be slightly increased by the TEG....... the same temperature. The PVs considered are crystalline Si (c-Si), amorphous Si (a-Si), copper indium gallium (di) selenide (CIGS) and cadmium telluride (CdTe) cells. The degradation of PV performance with temperature is shown to dominate the increase in power produced by the TEG, due to the low...

  2. Cadmium telluride quantum dots (CdTe-QDs and enhanced ultraviolet-B (UV-B radiation trigger antioxidant enzyme metabolism and programmed cell death in wheat seedlings.

    Directory of Open Access Journals (Sweden)

    Huize Chen

    Full Text Available Nanoparticles (NPs are becoming increasingly widespread in the environment. Free cadmium ions released from commonly used NPs under ultraviolet-B (UV-B radiation are potentially toxic to living organisms. With increasing levels of UV-B radiation at the Earth's surface due to the depletion of the ozone layer, the potential additive effect of NPs and UV-B radiation on plants is of concern. In this study, we investigated the synergistic effect of CdTe quantum dots (CdTe-QDs, a common form of NP, and UV-B radiation on wheat seedlings. Graded doses of CdTe-QDs and UV-B radiation were tested, either alone or in combination, based on physical characteristics of 5-day-old seedlings. Treatments of wheat seedlings with either CdTe-QDs (200 mg/L or UV-B radiation (10 KJ/m(2/d induced the activation of wheat antioxidant enzymes. CdTe-QDs accumulation in plant root cells resulted in programmed cell death as detected by DNA laddering. CdTe-QDs and UV-B radiation inhibited root and shoot growth, respectively. Additive inhibitory effects were observed in the combined treatment group. This research described the effects of UV-B and CdTe-QDs on plant growth. Furthermore, the finding that CdTe-QDs accumulate during the life cycle of plants highlights the need for sustained assessments of these interactions.

  3. Effects of Long-term exposure of Gelatinated and Non-gelatinated Cadmium Telluride Quantum Dots on Differentiated PC12 cells

    LENUS (Irish Health Repository)

    Prasad, Babu R

    2012-01-20

    Abstract Background The inherent toxicity of unmodified Quantum Dots (QDs) is a major hindrance to their use in biological applications. To make them more potent as neuroprosthetic and neurotherapeutic agents, thioglycolic acid (TGA) capped CdTe QDs, were coated with a gelatine layer and investigated in this study with differentiated pheochromocytoma 12 (PC12) cells. The QD - cell interactions were investigated after incubation periods of up to 17 days by MTT and APOTOX-Glo Triplex assays along with using confocal microscopy. Results Long term exposure (up to 17 days) to gelatinated TGA-capped CdTe QDs of PC12 cells in the course of differentiation and after neurites were grown resulted in dramatically reduced cytotoxicity compared to non-gelatinated TGA-capped CdTe QDs. Conclusion The toxicity mechanism of QDs was identified as caspase-mediated apoptosis as a result of cadmium leaking from the core of QDs. It was therefore concluded that the gelatine capping on the surface of QDs acts as a barrier towards the leaking of toxic ions from the core QDs in the long term (up to 17 days).

  4. Crystallographic, optical and electrical properties of low zinc content cadmium zinc sulphide composite thin films for photovoltaic applications

    International Nuclear Information System (INIS)

    Graphical abstract: The DC conductivity of the screen-printed Cd0.9Zn0.1S films was measured in vacuum by a two probe technique. The plot of ln σDC against 1000/T for Cd0.9Zn0.1S film is a straight line indicating that conduction in the film is through thermally activated process. Highlights: ► The method of preparing films of low zinc content i.e. Cd0.9Zn0.1S alloy by screen printing method is cost effective and reasonably accurate. ► The structural, optical and electrical studies of these films indicate that the films are quite suitable for photovoltaic device fabrication. ► The prepared films of Cd0.9Zn0.1S alloy are found to be polycrystalline in nature and have hexagonal (wurtzite) structure. ► The absorption coefficient of these films is high and is suitable for efficient absorption in the visible region of solar spectrum. ► It has been observed that the conduction in Cd0.9Zn0.1S films is through thermally activated process. - Abstract: In this paper a screen-printing method has been employed for the deposition of low zinc content cadmium zinc sulphide (Cd0.9Zn0.1S) composite thin films on ultra clean glass substrate. Cadmium sulphide, zinc sulphide and cadmium chloride have been used as the basic source material. With these basic source materials, the optimum conditions for preparing good quality screen-printed films have been found. X-ray diffraction studies revealed that the films are polycrystalline in nature, single phase exhibiting wurtzite (hexagonal) structure with strong preferential orientation of grains along the (1 0 1) direction. SEM/EDAX analysis confirms the formation of ternary compound. The optical band gap (Eg) of the films has been studied by using reflection spectra in wavelength range 350–600 nm. The DC conductivity of the films has been measured in vacuum by a two probe technique.

  5. Metals Production Requirements for Rapid Photovoltaics Deployment

    CERN Document Server

    Kavlak, Goksin; Jaffe, Robert L; Trancik, Jessika E

    2015-01-01

    If global photovoltaics (PV) deployment grows rapidly, the required input materials need to be supplied at an increasing rate. In this paper, we quantify the effect of PV deployment levels on the scale of metals production. For example, we find that if cadmium telluride {copper indium gallium diselenide} PV accounts for more than 3% {10%} of electricity generation by 2030, the required growth rates for the production of indium and tellurium would exceed historically-observed production growth rates for a large set of metals. In contrast, even if crystalline silicon PV supplies all electricity in 2030, the required silicon production growth rate would fall within the historical range. More generally, this paper highlights possible constraints to the rate of scaling up metals production for some PV technologies, and outlines an approach to assessing projected metals growth requirements against an ensemble of past growth rates from across the metals production sector. The framework developed in this paper may be...

  6. Photovoltaics

    International Nuclear Information System (INIS)

    This road-map proposes by the Group Total aims to inform the public on the photovoltaics. It presents the principles and the applications, the issues and the current technology, the challenges and the Group Total commitment in the domain. (A.L.B.)

  7. Module process optimization and device efficiency improvement for stable, low-cost, large-area, cadmium telluride-based photovoltaic module production

    Science.gov (United States)

    Albright, S. P.; Johnson, S. X.

    1994-06-01

    This report describes work performed under a three-phase subcontract. The objectives of the program include (1) achievement of active-area efficiencies of greater than 14% on small cells; (2) achievement of aperture-area efficiencies of greater than 13% on 0.09-sq m (1 sq ft) modules; (3) achievement of aperture-area efficiencies of greater than 12.5% on 0.37-sq m (4 sq ft) modules; and achievement of greater than 20-year module life (based on life testing extrapolations) with no greater than 10% efficiency degradation. The results obtained and described herein include the following: (1) efficiencies of 12.7% were achieved on small-area devices; (2) 0.09-sq m(1 sq ft) modules achieved greater than 8% aperture-area efficiency, but work for further efficiency improvement was redirected toward the 0.37-sq m(4 sq ft) modules; (3) 0.37-sq m (4 sq ft) modules achieved 26.5-W output, which calculates to 8.0% aperture-area efficiency; (4) consistent prototype production was focused on and substantially achieved within Phase 2; (5) life testing at the National Renewable Energy Laboratory showed no inherent stability problems with the CdTe technology, and the accuracy of module measurement was satisfactorily resolved; and (6) a 'cradle-to-cradle' recycling program was begun based upon the philosophy that the establishment of such mechanisms will be required to ensure maximum recapture and recycling of all manufacturing waste materials and/or modules returned from the field.

  8. Photorefractive properties of doped cadmium telluride

    Science.gov (United States)

    Bylsma, R. B.; Bridenbaugh, P. M.; Olson, D. H.; Glass, A. M.

    1987-09-01

    The first study of the photorefractive properties of doped CdTe has demonstrated high sensitivity for optical processing applications. Of the binary II-VI and III-V semiconductors, CdTe has the highest electro-optic coefficient r41 in the infrared, some three times larger than that of GaAs and InP. Deep levels introduced into CdTe exhibit appropriate absorption and photoconductivity at 1.06 μm by doping with V and Ti impurities. Photorefractive beam coupling experiments in CdTe:V gave small signal gains of 0.7 cm-1, and diffraction efficiencies with no applied electrical field of 0.7%. Thus, CdTe appears to be superior to previously studied III-V semiconductors, in the near-infrared spectrum. Optimization of doping and trap densities is expected to result in gain which exceeds the absorption loss, thereby allowing phase conjugation with infrared injection lasers.

  9. Thin film cadmium telluride solar cells

    Science.gov (United States)

    Chu, T. L.; Chu, Shirley S.; Ang, S. T.; Mantravadi, M. K.

    1987-08-01

    Thin-film p-CdTe/CdS/SnO2:F/glass solar cells of the inverted configuration were prepared by the deposition of p-type CdTe films onto CdS/SnO2:F/glass substrates using CVD or close-spaced sublimation (CSS) techniques based on the procedures of Chu et al. (1983) and Nicholl (1963), respectively. The deposition rates of p-CdTe films deposited by CSS were higher than those deposited by the CVD technique (4-5 min were sufficient), and the efficiencies higher than 10 percent were obtained. However, the resistivity of films prepared by CSS was not as readily controlled as that of the CVD films. The simplest technique to reduce the resistivity of the CSS p-CdTe films was to incorporate a dopant, such as As or Sb, into the reaction mixture during the preparation of the source material. The films with resistivities in the range of 500-1000 ohm cm were deposited in this manner.

  10. Thin-film cadmium telluride solar cells

    Science.gov (United States)

    Chu, T. L.

    1986-08-01

    The major objective of this work was to demonstrate CdTe devices grown by chemical vapor deposition (CVD) with a total area greater than 1 cm2 and photovoltic efficiencies of at least 13%. During the period covered, various processing steps were investigated for the preparation of thin-film CdTe heterojunction solar cells of the inverted configuration. Glass coated with fluorine-doped tin oxide was used as the substrate. Thin-film heterojunction solar cells were prepared by depositing p-CdTe films on substrates using CVD and close-spaced sublimation (CSS). Cells prepared from CSS CdTe usually have a higher conversion efficiency than those prepared from CVD CdTe, presumably due to the chemical interaction between CdS and CdTe at the interface during the CVD process. The best cell, about 1.2 sq cm in area, had an AM 1.5 (global) efficiency of 10.5%, and further improvements are expected by optimizing the process parameters.

  11. Evaluation of critical materials in five additional advance design photovoltaic cells

    Energy Technology Data Exchange (ETDEWEB)

    Smith, S.A.; Watts, R.L.; Martin, P.; Gurwell, W.E.

    1981-02-01

    The objective of this study is to identify potential material supply constraints due to the large-scale deployment of five advanced photovoltaic (PV) cell designs, and to suggest strategies to reduce the impacts of these production capacity limitations and potential future material shortages. The Critical Materials Assessment Program (CMAP) screens the designs and their supply chains and identifies potential shortages which might preclude large-scale use of the technologies. The results of the screening of five advanced PV cell designs are presented: (1) indium phosphide/cadmium sulfide, (2) zinc phosphide, (3) cadmium telluride/cadmium sulfide, (4) copper indium selenium, and (5) cadmium selenide photoelectrochemical. Each of these five cells is screened individually assuming that they first come online in 1991, and that 25 Gwe of peak capacity is online by the year 2000. A second computer screening assumes that each cell first comes online in 1991 and that each cell has a 5 GWe of peak capacity by the year 2000, so that the total online capacity for the five cells is 25 GWe. Based on a review of the preliminary baseline screening results, suggestions were made for varying such parameters as the layer thickness, cell production processes, etc. The resulting PV cell characterizations were then screened again by the CMAP computer code. The CMAP methodology used to identify critical materials is described; and detailed characterizations of the advanced photovoltaic cell designs under investigation, descriptions of additional cell production processes, and the results are presented. (WHK)

  12. NREL preprints for the 23rd IEEE Photovoltaic Specialists Conference

    Energy Technology Data Exchange (ETDEWEB)

    Fitzgerald, M. [ed.

    1993-05-01

    Topics covered include various aspects of solar cell fabrication and performance. Aluminium-gallium arsenides, cadmium telluride, amorphous silicon, and copper-indium-gallium selenides are all characterized in their applicability in solar cells.

  13. Photovoltaics: From the laboratory to the marketplace

    Energy Technology Data Exchange (ETDEWEB)

    Basso, T.S.; Surek, T.; Thornton, J.

    1991-03-01

    Photovoltaics (PV), the direct conversion of sunlight to electricity, is experiencing significant improvements in technology performance and lowered costs. Fostering these improvements, the SERI Photovoltaic Advanced Research and Development (PV AR D) Project supports research and provides services to the US PV industry. This paper presents the recent advances and future direction of the PV project. Research areas are Fundamental and Supporting Research, Advanced Thin-Film Materials, High-Efficiency Materials, Module Development, and Systems Development. Materials of interest include amorphous silicon, copper indium diselenide, cadmium telluride, crystalline silicon, gallium arsenide and related alloys, transparent conductors, antireflection coatings, substrates, and encapsulants. The PV project inherently provides technology transfer that helps industry shorten the time to bring R D advances to the marketplace. SERI annually performs over 10,000 measurements for the entire PV community, participates in collaborative research, and welcomes visiting scientists. Two specific areas of recently increased national focus are: (1) manufacturing processes for cost-effective PV modules, and (2) systems development for high-value utility applications. The SERI research approach is based on facilitating direct contact between industry, electric utilities, and others interested in PV technology. This approach heavily relies on SERI/industry partnerships. The arrangements vary to address generic and company-specific problems to improve the US industry's competitive position and accelerate greater electric utility deployment of PV systems. 5 refs., 5 figs., 6 tabs.

  14. Lead telluride alloy thermoelectrics

    Directory of Open Access Journals (Sweden)

    Aaron D. LaLonde

    2011-11-01

    Full Text Available The opportunity to use solid-state thermoelectrics for waste heat recovery has reinvigorated the field of thermoelectrics in tackling the challenges of energy sustainability. While thermoelectric generators have decades of proven reliability in space, from the 1960s to the present, terrestrial uses have so far been limited to niche applications on Earth because of a relatively low material efficiency. Lead telluride alloys were some of the first materials investigated and commercialized for generators but their full potential for thermoelectrics has only recently been revealed to be far greater than commonly believed. By reviewing some of the past and present successes of PbTe as a thermoelectric material we identify the issues for achieving maximum performance and successful band structure engineering strategies for further improvements that can be applied to other thermoelectric materials systems.

  15. Solar Photovoltaic Cells.

    Science.gov (United States)

    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…

  16. Properties of Electrodeposited Cadmium Sulfide Films for Photovoltaic Devices With Comparison to CdS Films Prepared by Other Methods

    OpenAIRE

    KADIRGAN, Figen

    2000-01-01

    Films of CdS for photovoltaic devices were electrochemically deposited on tin oxide coated glass substrates at different conditions. The films were found to be smooth and uniform with a small grain size. X-ray diffraction measurement and analysis indicated a hexagonal phase rather than the cubic phase. The surface composition of the films was investigated by Auger Spectroscopy. Electrochemical deposition parameters were studied to obtain the optimum conditions for the best CdS film...

  17. Energize Your Photovoltaics: NREL's Process Development and Integration Laboratory (PDIL)

    Energy Technology Data Exchange (ETDEWEB)

    2008-04-01

    The Process Development and Integration Laboratory (PDIL) at the National Renewable Energy Laboratory (NREL) is a unique collaborative facility where industry and universities can work closely with NREL scientists on integrated equipment to answer pressing questions related to photovoltaics (PV). The integrated equipment includes deposition, processing, and characterization tools. We work with a wide range of PV materials, from crystalline silicon to thin-films (amorphous, nano- and microcrystalline silicon, copper indium gallium diselenide, cadmium telluride) to organic PV. The PDIL integrates all the data to: Automate control via recipes; Share data easily and securely; and Facilitate analysis. The PDIL integrates all the tools to: Eliminate air exposure between steps; Sequence steps in any order ; and Incorporate combinatorial techniques. The PDIL integrates all the materials to: Provide greater device flexibility; Allow diverse experts to work together; and Better support industry and universities.

  18. CdTe Photovoltaics for Sustainable Electricity Generation

    Science.gov (United States)

    Munshi, Amit; Sampath, Walajabad

    2016-04-01

    Thin film CdTe (cadmium telluride) is an important technology in the development of sustainable and affordable electricity generation. More than 10 GW of installations have been carried out using this technology around the globe. It has been demonstrated as a sustainable, green, renewable, affordable and abundant source of electricity. An advanced sublimation tool has been developed that allows highly controlled deposition of CdTe films onto commercial soda lime glass substrates. All deposition and treatment steps can be performed without breaking the vacuum within a single chamber in an inline process that can be conveniently scaled to a commercial process. In addition, an advanced cosublimation source has been developed to allow the deposition of ternary alloys such as Cd x Mg1-x Te to form an electron reflector layer which is expected to address the voltage deficits in current CdTe devices and to achieve very high efficiency. Extensive materials characterization, including but not limited to scanning electron microscopy, transmission electron microscopy, energy dispersive x-ray spectroscopy, high resolution transmission electron microscopy and electron back-scatter diffraction, has been performed to get a better understanding of the effects of processing conditions on CdTe thin film photovoltaics. This combined with computer modeling such as density function theory modeling gives a new insight into the mechanism of CdTe photovoltaic function. With all these efforts, CdTe photovoltaics has seen great progress in the last few years. Currently, it has been recorded as the cheapest source of electricity in the USA on a commercial scale, and further improvements are predicted to further reduce the cost while increasing its utilization. Here, we give an overview of the advantages of thin film CdTe photovoltaics as well as a brief review of the challenges that need to be addressed. Some fundamental studies of processing conditions for thin film CdTe are also presented

  19. CdTe Photovoltaics for Sustainable Electricity Generation

    Science.gov (United States)

    Munshi, Amit; Sampath, Walajabad

    2016-09-01

    Thin film CdTe (cadmium telluride) is an important technology in the development of sustainable and affordable electricity generation. More than 10 GW of installations have been carried out using this technology around the globe. It has been demonstrated as a sustainable, green, renewable, affordable and abundant source of electricity. An advanced sublimation tool has been developed that allows highly controlled deposition of CdTe films onto commercial soda lime glass substrates. All deposition and treatment steps can be performed without breaking the vacuum within a single chamber in an inline process that can be conveniently scaled to a commercial process. In addition, an advanced cosublimation source has been developed to allow the deposition of ternary alloys such as Cd x Mg1- x Te to form an electron reflector layer which is expected to address the voltage deficits in current CdTe devices and to achieve very high efficiency. Extensive materials characterization, including but not limited to scanning electron microscopy, transmission electron microscopy, energy dispersive x-ray spectroscopy, high resolution transmission electron microscopy and electron back-scatter diffraction, has been performed to get a better understanding of the effects of processing conditions on CdTe thin film photovoltaics. This combined with computer modeling such as density function theory modeling gives a new insight into the mechanism of CdTe photovoltaic function. With all these efforts, CdTe photovoltaics has seen great progress in the last few years. Currently, it has been recorded as the cheapest source of electricity in the USA on a commercial scale, and further improvements are predicted to further reduce the cost while increasing its utilization. Here, we give an overview of the advantages of thin film CdTe photovoltaics as well as a brief review of the challenges that need to be addressed. Some fundamental studies of processing conditions for thin film CdTe are also presented

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

    Science.gov (United States)

    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.

  1. GEOLOGY OF THE FLORENCIA GOLD – TELLURIDE DEPOSIT (CAMAGÜEY, CUBA AND SOME METALLURGICAL CONSIDERATIONS

    Directory of Open Access Journals (Sweden)

    López K Jesús M.

    2006-12-01

    Full Text Available This paper describes the results from a study of the Florencia gold-telluride deposit in Central Cuba, including mineralogical, petrographical, microprobe and chemical analysis. Valuable information is provided for the exploration, mining and processing of gold ores from other nearby deposits with similar characteristics. Results highlight changes in the mineralogical composition of the ores between the north and south sectors of the deposit, as reflected in metallurgical concentrates after beneficiation and flotation of samples from these sectors.
    It is shown that gold deposits of the Cretaceous Volcanic Arc of Cuba largely consist of native gold, telluride and pyrite, where arsenopyrite is almost absent. Traces of lead, zinc and cadmium are present in the periphery of the main ore zones.

  2. Experience Scaling Up Manufacturing of Emerging Photovoltaic Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Braun, G. W.; Skinner, D. E.

    2007-01-01

    This report examines two important generic photovoltaic technologies at particularly revealing stages of development, i.e., the stages between R&D and stable commercial production and profitable sales. Based on two historical cases, it attempts to shed light on the difference between: (1) costs and schedules validated by actual manufacturing and market experience, and (2) estimated costs and schedules that rely on technology forecasts and engineering estimates. The amorphous Silicon case also identifies some of the costs that are incurred in meeting specific market requirements, while the Cadmium Telluride case identifies many of the operational challenges involved in transferring R&D results to production. The transition between R&D and commercial success takes a great deal of time and money for emerging energy conversion technologies in general. The experience reported here can be instructive to those managing comparable efforts, and to their investors. It can also be instructive to R&D managers responsible for positioning such new technologies for commercial success.

  3. Ellipsometric Studies on Silver Telluride Thin Films

    Directory of Open Access Journals (Sweden)

    M. Pandiaraman

    2011-01-01

    Full Text Available Silver telluride thin films of thickness between 45 nm and 145 nm were thermally evaporated on well cleaned glass substrates at high vacuum better than 10 – 5 mbar. Silver telluride thin films are polycrystalline with monoclinic structure was confirmed by X-ray diffractogram studies. AFM and SEM images of these films are also recorded. The phase ratio and amplitude ratio of these films were recorded in the wavelength range between 300 nm and 700 nm using spectroscopic ellipsometry and analysed to determine its optical band gap, refractive index, extinction coefficient, and dielectric functions. High absorption coefficient determined from the analysis of recorded spectra indicates the presence of direct band transition. The optical band gap of silver telluride thin films is thickness dependent and proportional to square of reciprocal of thickness. The dependence of optical band gap of silver telluride thin films on film thickness has been explained through quantum size effect.

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

    Energy Technology Data Exchange (ETDEWEB)

    Rohatgi, A.; Sudharsanan, R.; Ringel, S.A.; Chou, H.C. (Georgia Inst. of Tech., Atlanta, GA (United States))

    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.

  5. Mercury telluride as an ohmic contact to efficient thin film cadmium telluride solar cells

    International Nuclear Information System (INIS)

    The formation of a stable, reproducible, low-resistance contact to p-CdTe thin films is a major problem in the fabrication of efficient solar cells. Two general approaches to this problem are: the formation of a region of high carrier concentration under the contact to reduce the contact resistance, and the use of contact materials with a higher work function than p-CdTe. The second approach is investigated in this work using p-HgTe as the contact material. The deposition of p-HgTe on p-CdTe was carried out by the direct combination of the elemental vapors in a gas flow system and by the close-spaced sublimation, (CSS) technique. The process parameters in the direct combination technique are more readily controlled than those in the CSS technique. The p-HgTe/p-CdTe contact resistance has been found to be very similar to the Au/p-CdTe contact resistance

  6. A portable cadmium telluride multidetector probe for cardiac function monitoring

    CERN Document Server

    Arntz, Y; Dumitresco, B; Eclancher, B; Prat, V

    1999-01-01

    A new nuclear stethoscope based on a matrix of small CdTe semiconductor detectors has been developed for studying the cardiac performance by gamma ventriculography at the equilibrium, in rest and stress conditions, in the early and recovery phases of the coronary disease and to follow the long-term therapy. The light-weight probe consists of an array of 64 detectors 5x5x2 mm grouped in 16 independent units in a lead shielded aluminum box including 16 preamplifiers. The probe is connected to an electronic box containing DC power supply, 16 channel amplifiers, discriminators and counters, two analog-triggering ECG channels, and interface to a PC. The left ventricle activity is, preferentially, detected by using a low-resolution matching convergent collimator. A physical evaluation of the probe has been performed, both with static tests and dynamically with a hydraulic home-built model of beating heart ventricle paced by a rhythm simulator. The sum of the 16 detectors activity provided a radiocardiogram (RCG) wh...

  7. Cadmium telluride leaching behavior: Discussion of Zeng et al. (2015).

    Science.gov (United States)

    Sinha, Parikhit

    2015-11-01

    Zeng et al. (2015) evaluate the leaching behavior and surface chemistry of II-VI semiconductor materials, CdTe and CdSe, in response to pH and O2. Under agitation in acidic and aerobic conditions, the authors found approximately 3.6%-6.4% (w/w) solubility of Cd content in CdTe in the Toxicity Characteristic Leaching Procedure (TCLP), Waste Extraction Test (WET), and dissolution test, with lower solubility (0.56-0.58%) under agitation in acidic and anoxic conditions. This range is comparable with prior long-term transformation and dissolution testing and bio-elution testing of CdTe (2.3%-4.1% w/w solubility of Cd content in CdTe). The implications for potential leaching behavior of CdTe-containing devices require further data. Since CdTe PV modules contain approximately 0.05% Cd content by mass, the starting Cd content in the evaluation of CdTe-containing devices would be lower by three orders of magnitude than the starting Cd content in the authors' study, and leaching potential would be further limited by the monolithic glass-adhesive laminate-glass structure of the device that encapsulates the semiconductor material. Experimental evaluation of leaching potential of CdTe PV modules crushed by landfill compactor has been conducted, with results of TCLP and WET tests on the crushed material below regulatory limits for Cd. CdTe PV recycling technology has been in commercial operation since 2005 with high yields for semiconductor (95%) and glass (90%) recovery. PMID:26320011

  8. Acceptors in cadmium telluride. Identification and electronic structure

    International Nuclear Information System (INIS)

    It is shown that electronic properties of CdTe are determined by impurities more than by intrinsic defects like vacancies or interstitials in Cd or Te contrary to classical theories. These results are based on annealing, diffusion, implantation and electron irradiation at 4 K. Centers appearing in treated samples are accurately identified by photoluminescence, cathodoluminescence infra-red absorption, electrical measurements and magneto-optic properties. Acceptors identified are Li, Na, Cu, Ag and Au impurities in Cd and N, P and As in Te. Energy levels of all acceptors and fine structure of excitons are determined

  9. Polycrystalline cadmium telluride 3n-i-p solar cell

    Science.gov (United States)

    Meyers, P. V.

    1989-06-01

    The CdS/CdTe/ZnTe n-i-p solar cell and its ternary relatives have the potential to meet Department of Energy cost, efficiency, and stability goals. This report describes results of a continuing program to achieve these goals. A record-breaking efficiency of 11 percent has been demonstrated and verified at the Solar Energy Research Institute (SERI). Stability testing for 3000 hours indicates that the n-i-p structure is stable. Improving the short-circuit current by substituting Cd/sub x/Zn/sub 1-x/S for CdS has been successful and has produced 8 plus percent efficient cells with 2.6 eV windows using improved pyrolysis equipment. Transparent n-i-p devices have been produced with a SERI-verified efficiency of 9.4 percent . Collaborations with researchers at the Georgia Institute of Technology, the Institute of Energy Conversion, and Jet Propulsion Laboratory have resulted in jointly produced n-i-p cells. Cells produced by molecular beam epitaxy and metal organic chemical vapor deposition had efficiencies greater than 9 percent; cells produced by thermal vacuum evaporation had efficiencies greater than 7 percent.

  10. Laser-induced grating spectroscopy of cadmium telluride

    Science.gov (United States)

    Petrovic, Mark S.; Suchocki, Andrzej; Powell, Richard C.; Cantwell, Gene; Aldridge, Jeff

    1989-08-01

    Laser-induced transient gratings produced by two-photon absorption of picosecond pulses at 1.064 μm were used to examine the room-temperature nonlinear optical responses of CdTe crystals with different types of conductivity. Pulse-probe degenerate four-wave mixing measurements of grating dynamics on subnanosecond time scales were used to measure the ambipolar diffusion coefficient (Da) of charge carriers in the crystals. The value of Da =3.0 cm2 s-1 which was obtained is in very good agreement with theoretical estimates. A long-lived contribution to the signal consistent with a trapped charge photorefractive effect was observed at large grating spacings for n-type conductivity, and is tentatively attributed to a larger trap density in this sample. Measurements of the relative scattering efficiencies of successive diffracted orders in the Raman-Nath regime allowed for calculation of the laser-induced change in the index of refraction, due to the creation of free carriers. The value of Δn=4×10-4 which was obtained is in good agreement with theoretical estimates.

  11. High efficiency indium oxide/cadmium telluride solar cells

    Science.gov (United States)

    Nakazawa, T.; Takamizawa, K.; Ito, K.

    1987-02-01

    Solar cells have been fabricated by reactive deposition of thin-film n-In2O3 onto single-crystal p-CdTe. The cell has a total area solar power conversion efficiency of 13.4 percent which corresponds to an active area efficiency of 14.4 percent at air mass 1.5 without antireflection coatings. The cell consists of a buried homojunction structure with low dark saturation current density.

  12. Study and microscopic characterization of the cadmium telluride deep levels

    International Nuclear Information System (INIS)

    The spectroscopic methods PICTS, QTS and CTS were developed and perfected to investigate deep level analysis of high resistivity CdTe crystals which were either undoped, or doped with chlorine and copper. Crystals which were grown in space were also investigated. The main characterization of defect levels was determined and different correlations were established between the material's resistivity, chemical residues, dopant concentration and the nuclear radiation detector parameters. Using PICTS and CTS techniques, the generation of defects, under strong gamma-ray irradiation and particle bombardment was also studied. The influence of hydrogen on the main electrical characteristics of CdTe, in particular its ability to passivate the electrical activity of many deep defect and impurity states have been demonstrated. The compensation effects of Cl, Cu and H+ are interpreted using the qualitative models based on different possibilities of pairing or triplet formation between the ions of these dopants and those of defects

  13. Kinetics of plastic flow in cadmium telluride single crystal

    International Nuclear Information System (INIS)

    To identify the microscopic mechanism of plastic flow, we have analyzed temperature dependence of the critical resolved shear stress (CRSS) and of the activation volume for CdTe single crystals deformed in compression at various temperatures between 150 and 275K in terms of the kink-pair nucleation model of plastic flow in intrinsically strong crystals. In this model, stress-assisted thermally -activated kink-pair nucleation is considered to facilitate the passage of screw dislocation over a Peierls barrier. It is found that the yield stress tow depends on temperature T as tow/sup 0.5/ = A - BT, where A and B are positive constants, whereas the activation volume v varies with temperature T through the relation v/sup -I/ = C - DT, where C and D are positive constants. However, the slope of the straight line fitted to the data point in each case undergoes a change at a critical temperature 200K, indicating a transition in the rate process of yielding. For T direction in slip plane (Ill) was nearly equal to the distance between two neighboring Peierls valleys. But for T >200K, the maximum kink-pair height was almost twice the intervalley separation. We believe that the formation of kink-pair having a height larger than intervalley distance is hardly possible. Most probably stress-assisted thermally-activated breakaway of edge- dislocation segments from localized barriers, e.g. vacancies in above-equilibrium concentration, solid and gaseous residual impurities, dislocation debris formed during the stage of anelastic deformation of the specimen in the process of raising the stress from zero to the macro yield-point etc. determines the CRSS of nominally pure CdTe crystals in the temperature range 200 to 275K. (author)

  14. Compendium of photovoltaic degradation rates: Photovoltaic degradation rates

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, Dirk C. [National Renewable Energy Laboratory (NREL), 15013 Denver West Parkway Golden CO 80401 USA; Kurtz, Sarah R. [National Renewable Energy Laboratory (NREL), 15013 Denver West Parkway Golden CO 80401 USA; VanSant, Kaitlyn [Colorado School of Mines, 1500 Illinois Street Golden CO 8040 USA; Newmiller, Jeff [DNV GL, 2420 Camino Ramon, Suite 300 San Ramon CA 95483 USA

    2016-02-07

    Published data on photovoltaic (PV) degradation measurements were aggregated and re-examined. The subject has seen an increased interest in recent years resulting in more than 11 000 degradation rates in almost 200 studies from 40 different countries. As studies have grown in number and size, we found an impact from sampling bias attributable to size and accuracy. Because of the correlational nature of this study we examined the data in several ways to minimize this bias. We found median degradation for x-Si technologies in the 0.5-0.6%/year range with the mean in the 0.8-0.9%/year range. Hetero-interface technology (HIT) and microcrystalline silicon (..mu..c-Si) technologies, although not as plentiful, exhibit degradation around 1%/year and resemble thin-film products more closely than x-Si. Several studies showing low degradation for copper indium gallium selenide (CIGS) have emerged. Higher degradation for cadmium telluride (CdTe) has been reported, but these findings could reflect a convolution of less accurate studies and longer stabilization periods for some products. Significant deviations for beginning-of-life measurements with respect to nameplate rating have been documented over the last 35 years. Therefore, degradation rates that use nameplate rating as reference may be significantly impacted. Studies that used nameplate rating as reference but used solar simulators showed less variation than similar studies using outdoor measurements, even when accounting for different climates. This could be associated with confounding effects of measurement uncertainty and soiling that take place outdoors. Hotter climates and mounting configurations that lead to sustained higher temperatures may lead to higher degradation in some, but not all, products. Wear-out non-linearities for the worst performing modules have been documented in a few select studies that took multiple measurements of an ensemble of modules during the lifetime of the system. However, the majority

  15. Polycrystalline thin-film technology: Recent progress in photovoltaics

    Science.gov (United States)

    Mitchell, R. L.; Zweibel, K.; Ullal, H. S.

    1991-12-01

    Polycrystalline thin films have made significant technical progress in the past year. Three of these materials that have been studied extensively for photovoltaic (PV) power applications are copper indium diselenide (CuInSe2), cadmium telluride (CdTe), and thin film polycrystalline silicon (x-Si) deposited on ceramic substrates. The first of these materials, polycrystalline thin film CuInSe2, has made some rapid advances in terms of high efficiency and long term reliability. For CuInSe2 power modules, a world record has been reported on a 0.4 sq m module with an aperture-area efficiency of 10.4 pct. and a power output of 40.4 W. Additionally, outdoor reliability testing of CuInSe2 modules, under both loaded and open-circuit conditions, has resulted in only minor changes in module performance after more than 1000 days of continuous exposure to natural sunlight. CdTe module research has also resulted in several recent improvements. Module performance has been increased with device areas reaching nearly 900 sq cm. Deposition has been demonstrated by several different techniques, including electrodeposition, spraying, and screen printing. Outdoor reliability testing of CdTe modules was also carried out under both loaded and open-circuit conditions, with more than 600 days of continuous exposure to natural sunlight. These tests were also encouraging and indicated that the modules were stable within measurement error. The highest reported aperture-area module efficiency for CdTe modules is 10 pct.; the semiconductor material was deposited by electrodeposition. A thin-film CdTe photovoltaic system with a power output of 54 W has been deployed in Saudi Arabia for water pumping. The Module Development Initiative has made significant progress in support of the Polycrystalline Thin-Film Program in the past year, and results are presented in this paper.

  16. Polycrystalline thin-film technology: Recent progress in photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, R.L.; Zweibel, K.; Ullal, H.S.

    1991-12-01

    Polycrystalline thin films have made significant technical progress in the past year. Three of these materials that have been studied extensively for photovoltaic (PV) power applications are copper indium diselenide (CuInSe{sub 2}), cadmium telluride (CdTe), and thin-film polycrystalline silicon (x-Si) deposited on ceramic substrates. The first of these materials, polycrystalline thin-film CuInSe{sub 2}, has made some rapid advances in terms of high efficiency and long-term reliability. For CuInSe{sub 2} power modules, a world record has been reported on a 0.4-m{sup 2} module with an aperture-area efficiency of 10.4% and a power output of 40.4 W. Additionally, outdoor reliability testing of CuInSe{sub 2} modules, under both loaded and open-circuit conditions, has resulted in only minor changes in module performance after more than 1000 days of continuous exposure to natural sunlight. CdTe module research has also resulted in several recent improvements. Module performance has been increased with device areas reaching nearly 900 cm{sup 2}. Deposition has been demonstrated by several different techniques, including electrodeposition, spraying, and screen printing. Outdoor reliability testing of CdTe modules was also carried out under both loaded and open-circuit conditions, with more than 600 days of continuous exposure to natural sunlight. These tests were also encouraging and indicated that the modules were stable within measurement error. The highest reported aperture-area module efficiency for CdTe modules is 10%; the semiconductor material was deposited by electrodeposition. A thin-film CdTe photovoltaic system with a power output of 54 W has been deployed in Saudi Arabia for water pumping. The Module Development Initiative has made significant progress in support of the Polycrystalline Thin-Film Program in the past year, and results are presented in this paper.

  17. Electrodeposition and Characterization of Bismuth Telluride Nanowires

    Science.gov (United States)

    Frantz, C.; Stein, N.; Gravier, L.; Granville, S.; Boulanger, C.

    2010-09-01

    In this work, we report thermoelectric measurements on electroplated bismuth telluride nanowires. Porous polycarbonate membranes, obtained by ion-track irradiation lithography, were chosen as electroplating templates. Bismuth telluride nanowires were achieved in acidic media under potentiostatic conditions at -100 mV versus saturated silver chloride electrode. The filling ratio of the pores was increased to 80% by adding dimethyl sulfoxide to the electrolyte. Whatever the experimental conditions, the nanowires were polycrystalline in the rhombohedral phase of Bi2Te3. Finally, the power output of arrays of bismuth telluride nanowires was analyzed as a function of load resistance. The results were strongly dependent on the internal resistance, which can be significantly reduced by the presence of dimethyl sulfoxide during electroplating.

  18. 1.7 MeV电子辐照对CdTe太阳电池电流传输特性影响的图谱分析%Spectral Analysis of the Effects of 1.7 MeV Electron Irradiation on the Current Transfer Characteristic of Cadmium Telluride Solar Cells

    Institute of Scientific and Technical Information of China (English)

    田金秀; 曾广根; 何绪林; 张静全; 武莉莉; 李卫; 黎兵; 王文武; 冯良桓

    2014-01-01

    研究了1.7 MeV的电子辐照对具有Anti-radiation glass/ITO/ZnO/CdS/CdTe/ZnTe/ZnTe∶Cu/Ni结构的碲化镉多晶薄膜太阳电池器件性能的影响。抗辐照玻璃的使用,有效防止了普通玻璃受辐照后性能变化对测试结果的影响。利用光、暗I-V ,C-V ,QE ,AS等测试手段,分析了包括开路电压、短路电流、转换效率在内的电池性能。通过对比研究暗电流密度、分析了辐照对电池电流传输特性的影响。辐照后短路电流下降很大,电池效率明显降低。反向饱和电流密度有所增加,表明太阳电池的pn结特性受到损伤,而二极管理想因子几乎不变,说明太阳电池电流的输运机制未发生了变化。量子效率曲线证明是由于太阳电池结区损伤影响了光生载流子的收集。辐照使载流子浓度下降为原来的40.6%。导纳谱研究最终发生辐照会引入Cd2+缺陷能级,其位置为 Et -Ev =(0.58±0.02)eV ,俘获截面为1.78×10-16 cm2,表明辐照会影响光生载流子的产生,增加了载流子复合的概率,使得反向暗电流增大,最终导致电池的短路电流衰减。%The effects of device performance of 1.7 MeV electron irradiation on cadmium telluride polycrystal-line 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) ,ad-mittance spectrum (AS) and other testing methods were used to analyze cells performance such as the open-cir-cuit voltage (Voc) ,short-circuit current (Isc) ,fill factor (FF) and conversion efficiency (η) .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

  19. Cadmium carcinogenesis

    International Nuclear Information System (INIS)

    Cadmium is a heavy metal of considerable environmental and occupational concern. Cadmium compounds are classified as human carcinogens by several regulatory agencies. The most convincing data that cadmium is carcinogenic in humans comes from studies indicating occupational cadmium exposure is associated with lung cancer. Cadmium exposure has also been linked to human prostate and renal cancer, although this linkage is weaker than for lung cancer. Other target sites of cadmium carcinogenesis in humans, such as liver, pancreas and stomach, are considered equivocal. In animals, cadmium effectively induces cancers at multiple sites and by various routes. Cadmium inhalation in rats induces pulmonary adenocarcinomas, in accord with its role in human lung cancer. Cadmium can induce tumors and/or preneoplastic lesions within the rat prostate after ingestion or injection. At relatively high doses, cadmium induces benign testicular tumors in rats, but these appear to be due to early toxic lesions and loss of testicular function, rather than from a specific carcinogenic effect of cadmium. Like many other metals, cadmium salts will induce mesenchymal tumors at the site of subcutaneous (s.c.) or intramuscular (i.m.) injections, but the human relevance of these is dubious. Other targets of cadmium in rodents include the liver, adrenal, pancreas, pituitary, and hematopoietic system. With the exception of testicular tumors in rodents, the mechanisms of cadmium carcinogenesis are poorly defined. Cadmium can cause any number of molecular lesions that would be relevant to oncogenesis in various cellular model systems. Most studies indicate cadmium is poorly mutagenic and probably acts through indirect or epigenetic mechanisms, potentially including aberrant activation of oncogenes and suppression of apoptosis

  20. Damage in Monolithic Thin-Film Photovoltaic Modules Due to Partial Shade

    Energy Technology Data Exchange (ETDEWEB)

    Silverman, Timothy J.; Mansfield, Lorelle; Repins, Ingrid; Kurtz, Sarah

    2016-09-01

    The typical configuration of monolithic thin-film photovoltaic modules makes it possible for partial shade to place one or more cells in such a module in reverse bias. Reverse bias operation leads to high voltage, current density, and power density conditions, which can act as driving forces for failure. We showed that a brief outdoor shadow event can cause a 7% permanent loss in power. We applied an indoor partial shade durability test that moves beyond the standard hot spot endurance test by using more realistic mask and bias conditions and by carefully quantifying the permanent change in performance due to the stress. With the addition of a pass criterion based on change in maximum power, this procedure will soon be proposed as a part of the module-type qualification test. All six commercial copper indium gallium diselenide and cadmium telluride modules we tested experienced permanent damage due to the indoor partial shade test, ranging from 4% to 14% loss in maximum power. We conclude by summarizing ways to mitigate partial shade stress at the cell, module, and system levels.

  1. NREL photovoltaic subcontract reports: Abstracts and document control information, 1 August 1992--31 July 1993

    Energy Technology Data Exchange (ETDEWEB)

    1993-09-01

    This report contains document control information and abstracts for the National Renewable Energy Laboratory (NREL) subcontracted photovoltaic (PV) program publications. It also lists source information on additional publications that describe US Department of Energy (DOE) PV research activities. It is not totally exhaustive, so it lists NREL contacts for requesting further information on the DOE and NREL PV programs. This report covers the period from August 1, 1992, through July 31, 1993. This report is published periodically, with the previous one covering the period from August 1, 1991, through July 31, 1992. The purpose of continuing this type of publication is to help keep people abreast of specific PV interests, while maintaining a balance on the costs to the PV program. The information in this report is organized under PV technology areas: Amorphous Silicon Research; Polycrystalline Thin Films (including copper indium diselenide, cadmium telluride, and thin-film silicon); Crystalline Materials and Advanced Concepts (including silicon, gallium arsenide, and other group III-V materials); PV Manufacturing Technology Development (which may include manufacturing information for various types of PV materials).

  2. Fabrication of stable, large-area thin-film CdTe photovoltaic modules

    Science.gov (United States)

    Zhou, T. X.

    1995-06-01

    During the period of this subcontract, May 1991 through February 1995, Solar Cells, Inc. has developed and demonstrated a low-cost process to fabricate stable large-area cadmium telluride based thin-film photovoltaic modules. This report summarizes the final phase of the project which is concentrated on process optimization and product life tests. One of the major post-deposition process steps, the CdCl2 heat treatment, has been experimentally replaced with alternative treatments with vapor chloride or chlorine gas. Material and device qualities associated with alternative treatments are comparable or superior to those with the conventional treatment. Extensive experiments have been conducted to optimize the back-electrode structure in order to ensure long term device stability. Numerous small-area cells and minimodules have been subjected to a variety of stress tests, including but not limited to continuous light soak under open or short circuit or with resistive load, for over 10,000 hours. Satisfactory stability has been demonstrated on 48 and 64 sq cm minimodules under accelerated tests and on 7200 sq cm large modules under normal operating conditions. The conversion efficiency has also been significantly improved during this period. The total area efficiency of 7200 sq cm module has reached 8.4%, corresponding to a 60.3 W normalized output; the efficiency of 64 sq cm minimodules and 1.1 sq cm cells has reached 10.5% (aperture area) and 12.4% (total area), respectively.

  3. Systematic photovoltaic waste recycling

    Energy Technology Data Exchange (ETDEWEB)

    Palitzsch, Wolfram; Loser, Ulrich [Loser Chemie GmbH, Langenweissbach (Germany)

    2013-04-01

    Indium, selenium, tellurium, gallium, molybdenum, cadmium and silicon are some of the major elements used in photovoltaic cells. Fully aware of the limited availability of these metals in future, recycling has been recognized as the most advisable end-of-life strategy to save these raw materials from turning into production wastes. On the other hand, statutory measures such as 'Kreislaufwirtschaftsgesetz' (the German law encouraging closed-loop economy) aim to achieve a maximum quota of recycling and a minimum use of resources such as energy and raw materials. By the year of 2050, end-of-life photovoltaic panels are anticipated to amount to 9.57 million tons. Although we are not there yet, discussions on recycling have already started. We have to prepare for higher waste volumes expected in the coming years. But already today we need to solve some environmental problems like loss of conventional resources (e.g., glass) and rare metals. All of the known approaches for recycling photovoltaic semiconductor material seem economically and environmentally inefficient. In this paper, we report about reclaiming metals from scrap of thin film systems and associated photovoltaic manufacturing wastes like sandblasting dust and overspray. We also report one universal wet-chemical treatment for reclaiming the metals from CIS, CIGS or CdTe photovoltaic waste. Further, we discuss the application of our method to new PV systems, such as substrates other than glass (stainless steel, aluminum or plastic foil sheets) and alternative semiconductor alloys such as GaAs. (orig.)

  4. Optimum autonomous stand-alone photovoltaic system design on the basis of energy pay-back analysis

    International Nuclear Information System (INIS)

    Stand-alone photovoltaic (PV) systems comprise one of the most promising electrification solutions for covering the demand of remote consumers. However, such systems are strongly questioned due to extreme life-cycle (LC) energy requirements. For similar installations to be considered as environmentally sustainable, their LC energy content must be compensated by the respective useful energy production, i.e. their energy pay-back period (EPBP) should be found less than their service period. In this context, an optimum sizing methodology is currently developed, based on the criterion of minimum embodied energy. Various energy autonomous stand-alone PV-lead-acid battery systems are examined and two different cases are investigated; a high solar potential area and a medium solar potential area. By considering that the PV-battery (PV-Bat) system's useful energy production is equal to the remote consumer's electricity consumption, optimum cadmium telluride (CdTe) based systems yield the minimum EPBP (15 years). If achieving to exploit the net PV energy production however, the EPBP is found less than 20 years for all PV types. Finally, the most interesting finding concerns the fact that in all cases examined the contribution of the battery component exceeds 27% of the system LC energy requirements, reflecting the difference between grid-connected and stand-alone configurations.

  5. Optimum autonomous stand-alone photovoltaic system design on the basis of energy pay-back analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kaldellis, J.K.; Zafirakis, D. [Lab of Soft Energy Applications and Environmental Protection, TEI of Piraeus, P.O. Box 41046, Athens 12201 (Greece); Kondili, E. [Optimisation of Production Systems Lab, Mechanical Eng. Dept., TEI of Piraeus, P.O. Box 41046, Athens 12201 (Greece)

    2009-09-15

    Stand-alone photovoltaic (PV) systems comprise one of the most promising electrification solutions for covering the demand of remote consumers. However, such systems are strongly questioned due to extreme life-cycle (LC) energy requirements. For similar installations to be considered as environmentally sustainable, their LC energy content must be compensated by the respective useful energy production, i.e. their energy pay-back period (EPBP) should be found less than their service period. In this context, an optimum sizing methodology is currently developed, based on the criterion of minimum embodied energy. Various energy autonomous stand-alone PV-lead-acid battery systems are examined and two different cases are investigated; a high solar potential area and a medium solar potential area. By considering that the PV-battery (PV-Bat) system's useful energy production is equal to the remote consumer's electricity consumption, optimum cadmium telluride (CdTe) based systems yield the minimum EPBP (15 years). If achieving to exploit the net PV energy production however, the EPBP is found less than 20 years for all PV types. Finally, the most interesting finding concerns the fact that in all cases examined the contribution of the battery component exceeds 27% of the system LC energy requirements, reflecting the difference between grid-connected and stand-alone configurations. (author)

  6. Organic photovoltaics

    Science.gov (United States)

    Leo, Karl

    2016-08-01

    Organic photovoltaics are on the verge of revolutionizing building-integrated photovoltaics. For other applications, however, several basic open scientific questions need answering to, in particular, further improve energy-conversion efficiency and lifetime.

  7. Photovoltaic device

    Science.gov (United States)

    Reese, Jason A.; Keenihan, James R.; Gaston, Ryan S.; Kauffmann, Keith L.; Langmaid, Joseph A.; Lopez, Leonardo C.; Maak, Kevin D.; Mills, Michael E.; Ramesh, Narayan; Teli, Samar R.

    2015-06-02

    The present invention is premised upon an improved photovoltaic device ("PV device"), more particularly to an improved photovoltaic device with a multilayered photovoltaic cell assembly and a body portion joined at an interface region and including an intermediate layer, at least one interconnecting structural member, relieving feature, unique component geometry, or any combination thereof.

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

    Science.gov (United States)

    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 been characterized by light and dark current-voltage (I-V) measurements. Based on the I-V results samples were selected for Quantum Efficiency (QE), and I-V-T measurements. The goal of this project was to understand what properties of CdS are important for the formation of a good electrical CdS/CdTe junction and high efficiency solar cells. It was found that passivation of the CdS/CdTe interface is essential to obtain efficient devices. The passivation can be achieved by promoting mixing at the interface or by performing a heat treatment of the CdS surface prior to the CdTe deposition. For the latter case no noticeable intermixing at the CdS/CdTe interface occurs. Therefore, it is suggested that the CdS/CdTe interface is the most critical part of the device and the condition of the CdS surface just before CdTe deposition is one of the factors controlling its formation. To date, the best device has shown an efficiency of 15.1% as verified at the National Renewable Energy Laboratory. It is the highest efficiency reported for an all CSS fabricated solar cell. The best all CSS device fabricated on LOF glass substrate demonstrated an efficiency of 14.3%, which is a new record for the USF solar cell laboratory.

  9. New Layered Ternary Transition-Metal Tellurides

    Science.gov (United States)

    Mar, Arthur

    Several new ternary transition-metal tellurides, a class of compounds hitherto largely unexplored, have been synthesized and characterized. These are layered materials whose structures have been determined by single -crystal X-ray diffraction methods. The successful preparation of the compound TaPtTe_5 was crucial in developing an understanding of the MM'Te_5 (M = Nb, Ta; M' = Ni, Pd, Pt) series of compounds, which adopt either of two possible closely-related layered structures. Interestingly, the compound TaPdTe _5 remains unknown. Instead, the compound Ta_4Pd_3Te _{16} has been prepared. Its structure is closely related to that of the previously prepared compound Ta_3Pd _3Te_{14}. The physical properties of these compounds have been measured and correlated with the metal substitutions and interlayer separations. A new series of compounds, MM'Te _4 (M = Nb, Ta; M' = Ru, Os, Rh, Ir), has been discovered. The structure of NbIrTe_4 serves as a prototype: it is an ordered variant of the binary telluride WTe_2. Electronic band-structure calculations have been performed in order to rationalize the trends in metal-metal and tellurium -tellurium bonding observed in WTe_2 and the MM'Te_4 phases. Extension of these studies to include main-group metals has resulted in the synthesis of the new layered ternary germanium tellurides TiGeTe_6, ZrGeTe_4 , and HfGeTe_4. Because germanium can behave ambiguously in its role as a metalloid element, it serves as an anion by capping the metal-centered trigonal prisms and also as a cation in being coordinated in turn by other tellurium atoms in a trigonal pyramidal fashion. Structural relationships among these compounds are illustrated through the use of bicapped trigonal prisms and trigonal pyramids as the basic structural building blocks. The electrical and magnetic properties of these compounds have been measured. Insight into the unusual bonding and physical properties of these germanium-containing compounds has been gained through

  10. Photovoltaic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Duty, C.; Angelini, J.; Armstrong, B.; Bennett, C.; Evans, B.; Jellison, G. E.; Joshi, P.; List, F.; Paranthaman, P.; Parish, C.; Wereszczak, A.

    2012-10-15

    cells and modules in the field for 25 years. Under this project, Ferro leveraged world leading analytical capabilities at ORNL to characterize the paste-to-silicon interface microstructure and develop high efficiency next generation contact pastes. Ampulse Corporation is developing a revolutionary crystalline-silicon (c-Si) thin-film solar photovoltaic (PV) technology. Utilizing uniquely-textured substrates and buffer materials from the Oak Ridge National Laboratory (ORNL), and breakthroughs in Hot-Wire Chemical Vapor Deposition (HW-CVD) techniques in epitaxial silicon developed at the National Renewable Energy Laboratory (NREL), Ampulse is creating a solar technology that is tunable in silicon thickness, and hence in efficiency and economics, to meet the specific requirements of multiple solar PV applications. This project focused on the development of a high rate deposition process to deposit Si, Ge, and Si1-xGex films as an alternate to hot-wire CVD. Mossey Creek Solar is a start-up company with great expertise in the solar field. The primary interest is to create and preserve jobs in the solar sector by developing high-yield, low-cost, high-efficiency solar cells using MSC-patented and -proprietary technologies. The specific goal of this project was to produce large grain formation in thin, net-shape-thickness mc-Si wafers processed with high-purity silicon powder and ORNL's plasma arc lamp melting without introducing impurities that compromise absorption coefficient and carrier lifetime. As part of this project, ORNL also added specific pieces of equipment to enhance our ability to provide unique insight for the solar industry. These capabilities include a moisture barrier measurement system, a combined physical vapor deposition and sputtering system dedicated to cadmium-containing deposits, adeep level transient spectroscopy system useful for identifying defects, an integrating sphere photoluminescence system, and a high-speed ink jet printing system. These

  11. Photovoltaic Cells

    Directory of Open Access Journals (Sweden)

    Karolis Kiela

    2012-04-01

    Full Text Available The article deals with an overview of photovoltaic cells that are currently manufactured and those being developed, including one or several p-n junction, organic and dye-sensitized cells using quantum dots. The paper describes the advantages and disadvantages of various photovoltaic cells, identifies the main parameters, explains the main reasons for the losses that may occur in photovoltaic cells and looks at the ways to minimize them.Article in Lithuanian

  12. Thin-film photovoltaic power generation offers decreasing greenhouse gas emissions and increasing environmental co-benefits in the long term.

    Science.gov (United States)

    Bergesen, Joseph D; Heath, Garvin A; Gibon, Thomas; Suh, Sangwon

    2014-08-19

    Thin-film photovoltaic (PV) technologies have improved significantly recently, and similar improvements are projected into the future, warranting reevaluation of the environmental implications of PV to update and inform policy decisions. By conducting a hybrid life cycle assessment using the most recent manufacturing data and technology roadmaps, we compare present and projected environmental, human health, and natural resource implications of electricity generated from two common thin-film PV technologies-copper indium gallium selenide (CIGS) and cadmium telluride (CdTe)-in the United States (U.S.) to those of the current U.S. electricity mix. We evaluate how the impacts of thin films can be reduced by likely cost-reducing technological changes: (1) module efficiency increases, (2) module dematerialization, (3) changes in upstream energy and materials production, and (4) end-of-life recycling of balance of system (BOS). Results show comparable environmental and resource impacts for CdTe and CIGS. Compared to the U.S. electricity mix in 2010, both perform at least 90% better in 7 of 12 and at least 50% better in 3 of 12 impact categories, with comparable land use, and increased metal depletion unless BOS recycling is ensured. Technological changes, particularly efficiency increases, contribute to 35-80% reductions in all impacts by 2030. PMID:24984196

  13. Thin-film photovoltaic power generation offers decreasing greenhouse gas emissions and increasing environmental co-benefits in the long term.

    Science.gov (United States)

    Bergesen, Joseph D; Heath, Garvin A; Gibon, Thomas; Suh, Sangwon

    2014-08-19

    Thin-film photovoltaic (PV) technologies have improved significantly recently, and similar improvements are projected into the future, warranting reevaluation of the environmental implications of PV to update and inform policy decisions. By conducting a hybrid life cycle assessment using the most recent manufacturing data and technology roadmaps, we compare present and projected environmental, human health, and natural resource implications of electricity generated from two common thin-film PV technologies-copper indium gallium selenide (CIGS) and cadmium telluride (CdTe)-in the United States (U.S.) to those of the current U.S. electricity mix. We evaluate how the impacts of thin films can be reduced by likely cost-reducing technological changes: (1) module efficiency increases, (2) module dematerialization, (3) changes in upstream energy and materials production, and (4) end-of-life recycling of balance of system (BOS). Results show comparable environmental and resource impacts for CdTe and CIGS. Compared to the U.S. electricity mix in 2010, both perform at least 90% better in 7 of 12 and at least 50% better in 3 of 12 impact categories, with comparable land use, and increased metal depletion unless BOS recycling is ensured. Technological changes, particularly efficiency increases, contribute to 35-80% reductions in all impacts by 2030.

  14. Photovoltaic cell

    Science.gov (United States)

    Gordon, Roy G.; Kurtz, Sarah

    1984-11-27

    In a photovoltaic cell structure containing a visibly transparent, electrically conductive first layer of metal oxide, and a light-absorbing semiconductive photovoltaic second layer, the improvement comprising a thin layer of transition metal nitride, carbide or boride interposed between said first and second layers.

  15. Advances in thin-film solar cells for lightweight space photovoltaic power

    Science.gov (United States)

    Landis, Geoffrey A.; Bailey, Sheila G.; Flood, Dennis J.

    1989-01-01

    The present stature and current research directions of photovoltaic arrays as primary power systems for space are reviewed. There have recently been great advances in the technology of thin-film solar cells for terrestrial applications. In a thin-film solar cell the thickness of the active element is only a few microns; transfer of this technology to space arrays could result in ultralow-weight solar arrays with potentially large gains in specific power. Recent advances in thin-film solar cells are reviewed, including polycrystalline copper-indium selenide (CuInSe2) and related I-III-VI2 compounds, polycrystalline cadmium telluride and related II-VI compounds, and amorphous silicon:hydrogen and alloys. The best experimental efficiency on thin-film solar cells to date is 12 percent AMO for CuIn Se2. This efficiency is likely to be increased in the next few years. The radiation tolerance of thin-film materials is far greater than that of single-crystal materials. CuIn Se2 shows no degradation when exposed to 1 MeV electrons. Experimental evidence also suggests that most of all of the radiation damage on thin-films can be removed by a low temperature anneal. The possibility of thin-film multibandgap cascade solar cells is discussed, including the tradeoffs between monolithic and mechanically stacked cells. The best current efficiency for a cascade is 12.5 percent AMO for an amorphous silicon on CuInSe2 multibandgap combination. Higher efficiencies are expected in the future. For several missions, including solar-electric propulsion, a manned Mars mission, and lunar exploration and manufacturing, thin-film photovolatic arrays may be a mission-enabling technology.

  16. NCPV preprints for the 2. world conference on photovoltaic solar energy conversion

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-09-01

    The proceedings contain 26 papers arranged under the following topical sections: Silicon (3 papers); Thin-film PV technologies (11 papers): amorphous silicon, cadmium telluride, copper indium diselenide, and high efficiency devices; Module and BOS manufacturing (2 papers); Cell, module, and system testing (7 papers); and Market development (3 papers). Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.

  17. Photovoltaic device

    DEFF Research Database (Denmark)

    2011-01-01

    A photovoltaic cell module including a plurality of serially connected photovoltaic cells on a common substrate, each including a first electrode, a printed light-harvesting layer and a printed second electrode, wherein at least one of the electrodes is transparent, and wherein the second electrode...... of a first cell is printed such that it forms an electrical contact with the first electrode of an adjacent second cell without forming an electrical contact with the first electrode of the first cell or the light-harvesting layer of the second cell, and a method of making such photovoltaic cell modules....

  18. The Archaean gold-telluride-sulphide and gold-telluride mineralisation of a multiple stage hydrothermal vein deposit at the Commoner Mine, Zimbabwe

    International Nuclear Information System (INIS)

    The Commoner Mine is situated on the western edge of the Midlands greenstone belt, 50 km west-southwest of Kadoma, Zimbabwe. Current geological interest in this deposit was initiated by the presence of coarse grained telluride minerals in ore exposed on 21 level in 1978. The deposit is a hydrothermal quartz-calcite vein. It was found that coarse grained gold-silver tellurides fill fractures which transect the telluride breccia. Comparison of the physical and mineralogical characteristics of the Commoner orebody with those of the Tertiary gold-telluride deposits of the Circum Pacific Belt and the Archaean deposits of Canada and Australia indicates that this mineralisation was probably deposited in a near-surface environment. It was found that the gold-telluride ores of the Commoner Mine display features characteristic of both plutonic-hydrothermal and volcanic-hydrothermal styles of telluride mineralisation

  19. Photovoltaic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Duty, C.; Angelini, J.; Armstrong, B.; Bennett, C.; Evans, B.; Jellison, G. E.; Joshi, P.; List, F.; Paranthaman, P.; Parish, C.; Wereszczak, A.

    2012-10-15

    cells and modules in the field for 25 years. Under this project, Ferro leveraged world leading analytical capabilities at ORNL to characterize the paste-to-silicon interface microstructure and develop high efficiency next generation contact pastes. Ampulse Corporation is developing a revolutionary crystalline-silicon (c-Si) thin-film solar photovoltaic (PV) technology. Utilizing uniquely-textured substrates and buffer materials from the Oak Ridge National Laboratory (ORNL), and breakthroughs in Hot-Wire Chemical Vapor Deposition (HW-CVD) techniques in epitaxial silicon developed at the National Renewable Energy Laboratory (NREL), Ampulse is creating a solar technology that is tunable in silicon thickness, and hence in efficiency and economics, to meet the specific requirements of multiple solar PV applications. This project focused on the development of a high rate deposition process to deposit Si, Ge, and Si1-xGex films as an alternate to hot-wire CVD. Mossey Creek Solar is a start-up company with great expertise in the solar field. The primary interest is to create and preserve jobs in the solar sector by developing high-yield, low-cost, high-efficiency solar cells using MSC-patented and -proprietary technologies. The specific goal of this project was to produce large grain formation in thin, net-shape-thickness mc-Si wafers processed with high-purity silicon powder and ORNL's plasma arc lamp melting without introducing impurities that compromise absorption coefficient and carrier lifetime. As part of this project, ORNL also added specific pieces of equipment to enhance our ability to provide unique insight for the solar industry. These capabilities include a moisture barrier measurement system, a combined physical vapor deposition and sputtering system dedicated to cadmium-containing deposits, adeep level transient spectroscopy system useful for identifying defects, an integrating sphere photoluminescence system, and a high-speed ink jet printing system. These

  20. Applications of thin-film photovoltaics for space

    Science.gov (United States)

    Landis, Geoffrey A.; Hepp, Aloysius F.

    1991-01-01

    The authors discuss the potential applications of thin-film polycrystalline and amorphous cells for space. There have been great advances in thin-film solar cells for terrestrial applications. Transfer of this technology to space applications could result in ultra low-weight solar arrays with potentially large gains in specific power. Recent advances in thin-film solar cells are reviewed, including polycrystalline copper indium selenide and related I-III-VI2 compounds, polycrystalline cadmium telluride and related II-VI compounds, and amorphous silicon arrays. The possibility of using thin-film multi-bandgap cascade solar cells is discussed.

  1. Thin-Film Photovoltaics: Status and Applications to Space Power

    Science.gov (United States)

    Landis, Geoffrey A.; Hepp, Aloysius F.

    1991-01-01

    The potential applications of thin film polycrystalline and amorphous cells for space are discussed. There have been great advances in thin film solar cells for terrestrial applications; transfer of this technology to space applications could result in ultra low weight solar arrays with potentially large gains in specific power. Recent advances in thin film solar cells are reviewed, including polycrystalline copper iridium selenide and related I-III-VI2 compounds, polycrystalline cadmium telluride and related II-VI compounds, and amorphous silicon alloys. The possibility of thin film multi bandgap cascade solar cells is discussed.

  2. Lead telluride with increased mechanical stability for cylindrical thermoelectric generators

    International Nuclear Information System (INIS)

    The aim of this work is to improve the mechanical stability of lead telluride (PbTe), trying to vary its mechanical properties independently from its thermoelectric properties. Thus the influence of material preparation as well as different dopants on the mechanical and thermoelectric properties of lead telluride is being analysed. When using appropriately set process parameters, milling and sintering of lead telluride increases the material's hardness. With sintering temperatures exceeding 300 C stable material of high relative density can be achieved. Milling lead telluride generates lattice defects leading to a reduction of the material's charge carrier density. These defects can be reduced by increased sintering temperatures. Contamination of the powder due to the milling process leads to bloating during thermal cycling and thus reduced density of the sintered material. In addition to that, evaporation of tellurium at elevated temperatures causes instability of the material's thermoelectric properties. Based on the experimental results obtained in this work, the best thermoelectric and mechanical properties can be obtained by sintering coarse powders at around 400 C. Within this work a concept was developed to vary the mechanical properties of lead telluride via synthesis of PbTe with electrically nondoping elements, which thus may keep the thermoelectric properties unchanged. Therefore, the mechanical and thermoelectric properties of Pb1-xCaxTe were investigated. Doping pure PbTe with calcium causes a significant increase of the material's hardness while only slightly decreasing the charge carrier density and thus keeping the thermoelectric properties apart from a slight reduction of the electrical conductivity nearly unchanged. The abovementioned concept is proven using sodium doped lead telluride, as it is used for thermoelectric generators: The additional doping with calcium again increases the material's hardness while its thermoelectric properties remain

  3. High-temperature thermoelectric behavior of lead telluride

    Indian Academy of Sciences (India)

    M P Singh; C M Bhandari

    2004-06-01

    Usefulness of a material in thermoelectric devices is temperature specific. The central problem in thermoelectric material research is the selection of materials with high figure-of-merit in the given temperature range of operation. It is of considerable interest to know the utility range of the material, which is decided by the degrading effect of minority carrier conduction. Lead telluride is among the best-known materials for use in the temperature range 400—900 K. This paper presents a detailed theoretical investigation of the role of minority carriers in degrading the thermoelectric properties of lead telluride and outlines the temperature range for optimal performance.

  4. Photovoltaic business

    OpenAIRE

    Štefan, Petr

    2011-01-01

    The work is focused on business photovoltaic performance as one of the alternative sources of electrical power. Theoretical part was created by quoting work up documents. Literature search was divided into several parts. The first part revolves around the solar radiation and its advantages and disadvantages. In the second part is speaking about the variations of using solar energy from heating the water to generate electric energy. It also deals with photovoltaic power plants in the world and...

  5. Phase transition of bismuth telluride thin films grown by MBE

    DEFF Research Database (Denmark)

    Fülöp, Attila; Song, Yuxin; Charpentier, Sophie;

    2014-01-01

    A previously unreported phase transition between Bi2Te3 and Bi4Te3 in bismuth telluride grown by molecular beam epitaxy is recorded via XRD, AFM, and SIMS observations. This transition is found to be related to the Te/Bi beam equivalent pressure (BEP) ratio. BEP ratios below 17 favor the formatio...

  6. Understanding the Meaning of the Entrance Image: The Telluride Process.

    Science.gov (United States)

    Garnham, Harry L.; Garnham, Penny

    1989-01-01

    Describes a project to define the images of Telluride (Colorado) held by its residents and tourists and contributing to sense of place. Discusses the design of the town's entry points and efforts to maintain their visual environments in harmony with the town's defined character during ongoing community development. (SV)

  7. Spectroscopic Ellipsometry Studies of Ag and ZnO Thin Films and Their Interfaces for Thin Film Photovoltaics

    Science.gov (United States)

    Sainju, Deepak

    Many modern optical and electronic devices, including photovoltaic devices, consist of multilayered thin film structures. Spectroscopic ellipsometry (SE) is a critically important characterization technique for such multilayers. SE can be applied to measure key parameters related to the structural, optical, and electrical properties of the components of multilayers with high accuracy and precision. One of the key advantages of this non-destructive technique is its capability of monitoring the growth dynamics of thin films in-situ and in real time with monolayer level precision. In this dissertation, the techniques of SE have been applied to study the component layer materials and structures used as back-reflectors and as the transparent contact layers in thin film photovoltaic technologies, including hydrogenated silicon (Si:H), copper indium-gallium diselenide (CIGS), and cadmium telluride (CdTe). The component layer materials, including silver and both intrinsic and doped zinc oxide, are fabricated on crystalline silicon and glass substrates using magnetron sputtering techniques. These thin films are measured in-situ and in real time as well as ex-situ by spectroscopic ellipsometry in order to extract parameters related to the structural properties, such as bulk layer thickness and surface roughness layer thickness and their time evolution, the latter information specific to real time measurements. The index of refraction and extinction coefficient or complex dielectric function of a single unknown layer can also be obtained from the measurement versus photon energy. Applying analytical expressions for these optical properties versus photon energy, parameters that describe electronic transport, such as electrical resistivity and electron scattering time, can be extracted. The SE technique is also performed as the sample is heated in order to derive the effects of annealing on the optical properties and derived electrical transport parameters, as well as the

  8. Concentrator Photovoltaics

    CERN Document Server

    Luque, Antonio L

    2007-01-01

    Photovoltaic solar-energy conversion is one of the most promising technologies for generating renewable energy, and conversion of concentrated sunlight can lead to reduced cost for solar electricity. In fact, photovoltaic conversion of concentrated sunlight insures an efficient and cost-effective sustainable power resource. This book gives an overview of all components, e.g. cells, concentrators, modules and systems, for systems of concentrator photovoltaics. The authors report on significant results related to design, technology, and applications, and also cover the fundamental physics and market considerations. Specific contributions include: theory and practice of sunlight concentrators; an overview of concentrator PV activities; a description of concentrator solar cells; design and technology of modules and systems; manufacturing aspects; and a market study.

  9. Organic photovoltaics

    DEFF Research Database (Denmark)

    Demming, Anna; Krebs, Frederik C; Chen, Hongzheng

    2013-01-01

    Energy inflation, the constant encouragement to economize on energy consumption and the huge investments in developing alternative energy resources might seem to suggest that there is a global shortage of energy. Far from it, the energy the Sun beams on the Earth each hour is equivalent to a year......'s supply, even at our increasingly ravenous rate of global energy consumption [1]. But it's not what you have got it's what you do with it. Hence the intense focus on photovoltaic research to find more efficient ways to harness energy from the Sun. Recently much of this research has centred on organic...... solar cells since they offer simple, low-cost, light-weight and large-area flexible photovoltaic structures. This issue with guest editors Frederik C Krebs and Hongzheng Chen focuses on some of the developments at the frontier of organic photovoltaic technology. Improving the power conversion efficiency...

  10. Applied photovoltaics

    CERN Document Server

    Wenham, Stuart R; Watt, Muriel E; Corkish, Richard; Sproul, Alistair

    2013-01-01

    The new edition of this thoroughly considered textbook provides a reliable, accessible and comprehensive guide for students of photovoltaic applications and renewable energy engineering. Written by a group of award-winning authors it is brimming with information and is carefully designed to meet the needs of its readers. Along with exercises and references at the end of each chapter, it features a set of detailed technical appendices that provide essential equations, data sources and standards. The new edition has been fully updated with the latest information on photovoltaic cells,

  11. Estimation of Thickness and Cadmium Composition Distributions in HgCdTe Focal Plane Arrays

    Science.gov (United States)

    Mouzali, S.; Lefebvre, S.; Rommeluère, S.; Ferrec, Y.; Primot, J.

    2016-09-01

    Mercury cadmium telluride (HgCdTe) is one of the most commonly used material systems for infrared detection. The performance of infrared focal-plane arrays (IRFPAs) based on this material is limited by several noise sources. In this paper, we focus on the fixed pattern noise, which is related to disparities between the spectral responses of pixels. In our previous work, we showed that spectral nonuniformities in a HgCdTe IRFPA were caused by inhomogeneities of thickness and cadmium composition in the HgCdTe layer, using an optical description of the pixel structure. We propose to use this bidimensional dependence combined with experimental spectral responses to estimate disparities of thickness and cadmium composition in a specific HgCdTe-based IRFPA. The estimation methods and the resulting maps are presented, highlighting the accuracy of this nondestructive method.

  12. Chalcogenide photovoltaic solar cells of special interest

    Energy Technology Data Exchange (ETDEWEB)

    Champness, C.H. (McGill Univ., Montreal, Quebec (Canada))

    1988-08-01

    A brief review is given of those semiconducting selenides and tellurides that appear suitable for the absorber layer of a photovoltaic solar cell, with energy gaps in the range 1 to 2 eV. Furthermore, to obtain a lower cost cell, the semiconductor is also required to be used in the form of a thin polycrystalline film, necessitating a high optical absorption coefficient in the material. At the present time the two best chalcogenides meeting these requirements are the compounds CuInSe{sub 2} and CdTe, both of which have been used in polycrystalline thin film structures with CdS, as the window layer, yielding conversion efficiencies of over 10%. They have also demonstrated very good chemical stability.

  13. Photovoltaic energy

    Science.gov (United States)

    1990-01-01

    In 1989, the U.S. photovoltaic industry enjoyed a growth rate of 30 percent in sales for the second year in a row. This sends a message that the way we think about electricity is changing. Instead of big energy projects that perpetuate environmental and economic damage, there is a growing trend toward small renewable technologies that are well matched to end-user needs and operating conditions. As demand grows and markets expand, investment capital will be drawn to the industry and new growth trends will emerge. The photovoltaic industry around the world achieved record shipments also. Worldwide shipments of photovoltaic (PV) modules for 1989 totaled more than 40 megawatts (MW), nearly a 20 percent increase over last year's shipments. The previous two years showed increases in worldwide shipments of 23 and 25 percent, respectively. If this growth rate continues through the 1990s, as industry back orders would indicate, 300 to 1000 MW of PV-supplied power could be on line by 2000. Photovoltaic systems have low environmental impact and they are inexpensive to operate and maintain. Using solid-state technology, PV systems directly convert sunlight to electricity without high-temperature fluids or moving parts that could cause mechanical failure. This makes the technology very reliable.

  14. Kelvin Probe Studies of Cesium Telluride Photocathode for AWA Photoinjector

    CERN Document Server

    Wisniewski, Eric; Yusof, Zikri; Spentzouris, Linda; Terry, Jeff; Harkay, Katherine

    2012-01-01

    Cesium telluride is an important photocathode as an electron source for particle accelerators. It has a relatively high quantum efficiency (>1%), is sufficiently robust in a photoinjector, and has a long lifetime. This photocathode is grown in-house for a new Argonne Wakefield Accelerator (AWA) beamline to produce high charge per bunch (~50 nC) in a long bunch train. Here, we present a study of the work function of cesium telluride photocathode using the Kelvin Probe technique. The study includes an investigation of the correlation between the quantum efficiency and the work function, the effect of photocathode aging, the effect of UV exposure on the work function, and the evolution of the work function during and after photocathode rejuvenation via heating.

  15. Tunneling behavior of bismuth telluride nanoplates in electrical transport

    OpenAIRE

    Eginligil, Mustafa; Zhang, Weiqing; Kalitsov, Alan; Lu, Xianmao; Yang, Hyunsoo

    2012-01-01

    We study the electrical transport properties of ensembles of bismuth telluride (Bi2Te3) nanoplates grown by solution based chemical synthesis. Devices consisting of Bi2Te3 nanoplates are fabricated by surface treatment after dropping the solution on the structured gold plates and the temperature dependence of resistance shows a nonmetallic behavior. Symmetric tunneling behavior in I-V was observed in both our experimental results and theoretical calculation of surface conductance based on a s...

  16. Solvothermal synthesis and study of nonlinear optical properties of nanocrystalline thallium doped bismuth telluride

    Energy Technology Data Exchange (ETDEWEB)

    Molli, Muralikrishna, E-mail: muralikrishnamolli@sssihl.edu.in [Department of Physics, Sri Sathya Sai Institute of Higher Learning, Prasanthinilayam-515 134 (India); Parola, Sowmendran; Avinash Chunduri, L.A.; Aditha, Saikiran; Sai Muthukumar, V; Mimani Rattan, Tanu; Kamisetti, Venkataramaniah [Department of Physics, Sri Sathya Sai Institute of Higher Learning, Prasanthinilayam-515 134 (India)

    2012-05-15

    Nanocrystalline Bismuth telluride and thallium (4 mol %) doped Bismuth telluride were synthesized through hydrothermal method. The as-prepared products were characterized using Powder X-ray Diffraction, High Resolution Transmission Electron Microscopy, Energy Dispersive X-Ray Spectroscopy, UV-Visible spectroscopy and Fourier Transform Infrared Spectroscopy. Powder XRD results revealed the crystalline nature of the obtained phases. HRTEM showed the particle-like morphology of the products. The decrease in the absorption coefficient due to thallium doping was observed in FTIR spectra. The intensity dependent nonlinear optical properties of nanocrystalline bismuth telluride and thallium doped bismuth telluride were studied using the Z-scan technique in open-aperture configuration. Bismuth telluride doped with thallium showed enhanced nonlinear optical response compared to pristine bismuth telluride and hence could be used as a potential candidate for optical power limiting applications. - Graphical Abstract: Nonlinear transmission (Z-scan) curves of nanocrystalline bismuth telluride ({Delta}) and thallium doped bismuth telluride ({open_square}). Thallium doped bismuth telluride showed enhanced nonlinear absorption compared to bismuth telluride. Inset: TEM micrograph of bismuth telluride nanocrystallites. Highlights: Black-Right-Pointing-Pointer Synthesis of Nanocrystalline Bi{sub 2}Te{sub 3} and Thallium doped Bi{sub 2}Te{sub 3} through solvothermal method. Black-Right-Pointing-Pointer Reduced absorption coefficient due to thallium doping found from IR spectroscopy. Black-Right-Pointing-Pointer Open-aperture Z-scan technique for nonlinear optical studies. Black-Right-Pointing-Pointer Two photon absorption based model for theoretical fitting of Z-scan data. Black-Right-Pointing-Pointer Enhanced nonlinear absorption in Thallium doped Bi{sub 2}Te{sub 3} - potential candidate for optical power limiting applications.

  17. Photovoltaic Wire Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project will investigate a new architecture for photovoltaic devices based on nanotechnology: photovoltaic wire. The...

  18. Roof Photovoltaic Test Facility

    Data.gov (United States)

    Federal Laboratory Consortium — In order to accurately predict the annual energy production of photovoltaic systems for any given geographical location, building orientation, and photovoltaic cell...

  19. Temperature-dependent adsorption of tellurium and mercury species on cadmium telluride studied by spectroscopic ellipsometry

    Science.gov (United States)

    Badano, Giacomo

    In this study, a subsonic molecular beam of Hg was directed on CdTe surfaces and the absorption spectra were measured for the first time by ellipsometry. We analyze the optical spectra of Hg adsorbed on CdTe surfaces, over the range 1.6--4.5 eV, for a variety of temperatures and Hg fluxes. When a CdTe(211)B surface is subjected to a Hg flux, various effects can occur. Hg will be present on and just beneath the surface in a variety of forms: chemisorbed on the Te sites or on excess Te (forming a 2D surface, 1D chains or isolated atoms or clusters), physisorbed as a 2D liquid, or diffused into the CdTe bulk. In our analysis of the change in the pseudo dielectric function, we made several approximations. We treated the different constituents as separate layers, which is strictly speaking not true, because the various Hg forms are probably mixed. Second, we used the 3D form of the Hg1- xCdxTe e(□; x) dielectric function to mimic chemisorbed Hg on the surface. Also, we used a Drude function to model the presence of physisorbed Hg, although that is probably a good approximation. Third, we fit only the imaginary part of the dielectric function, , because it has a more direct physical meaning, and unlike the real part does not depend on the presence of out-of-range critical points. In addition, the limited resolution of the M88 ellipsometer prevented us from using a critical point analysis to interpret the data. These limitations notwithstanding, our analysis gives surprisingly good results, in that it reproduces the expected dependence of the thickness of the chemisorbed and physisorbed components correctly as a function of temperature and pressure and gives reasonable values for the composition of the Hg1-xCd xTe. Although we do not at present believe the absolute numbers that the analysis provides, we believe that this approach confirms our general ideas regarding the nature of the CdTe(211) surface under Hg, and is valuable at least technologically, to obtain a reliable run-to-run characterization of the surface before growth.

  20. Modeling effects of solute concentration in Bridgman growth of cadmium zinc telluride

    Science.gov (United States)

    Stelian, Carmen; Duffar, Thierry

    2016-07-01

    Numerical modeling is used to investigate the effect of solute concentration on the melt convection and interface shape in Bridgman growth of Cd1-x Znx Te (CZT). The numerical analysis is compared to experimental growth in cylindrical ampoules having a conical tip performed by Komar et al. (2001) [15]. In these experiments, the solidification process occurs at slow growth rate (V = 2 ṡ10-7 m / s) in a thermal field characterized by a vertical gradient GT = 20 K / cm at the growth interface. The computations performed by accounting the solutal effect show a progressive damping of the melt convection due to the depleted Zn at the growth interface. The computed shape of the crystallization front is in agreement with the experimental measurement showing a convex-concave shape for the growth through the conical part of the ampoule and a concave shape of the interface in the cylindrical region. The distribution of Zn is nearly uniform over the crystal length except for the end part of the ingots. The anomalous zinc segregation observed in some experiments is explained by introducing the hypothesis of incomplete charge mixing during the homogenization time which precedes the growth process. When the crystallization is started in ampoules having a very sharp conical tip, the heavy CdTe is accumulated at the bottom part of the melt, giving rise to anomalous segregation patterns, featuring very low zinc concentration in the ingots during the first stage of the solidification.

  1. Nature of physical processes in solar cells utilizing cadmium telluride--electrolyte junctions

    Energy Technology Data Exchange (ETDEWEB)

    Panosyan, Z.R.; Arutyunyan, V.M.; Meliksetyan, V.A.

    1985-09-01

    An investigation was made of the physical processes occurring in photoelectrochemical conversion of solar energy by a CdTe--electrolyte junction involving surface exciton and electron states. The influence of these processes on the efficiency of conversion of solar energy into chemical energy of hydrogen was analyzed.

  2. Thin film cadmium telluride charged particle sensors for large area neutron detectors

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, J. W.; Smith, L.; Calkins, J.; Mejia, I.; Cantley, K. D.; Chapman, R. A.; Quevedo-Lopez, M.; Gnade, B., E-mail: gnade@utdallas.edu [Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080 (United States); Kunnen, G. R.; Allee, D. R. [Flexible Display Center, Arizona State University, Phoenix, Arizona 85284 (United States); Sastré-Hernández, J.; Contreras-Puente, G. [Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Mexico City 07738 (Mexico); Mendoza-Pérez, R. [Universidad Autónoma de la Ciudad de México, Mexico City 09790 (Mexico)

    2014-09-15

    Thin film semiconductor neutron detectors are an attractive candidate to replace {sup 3}He neutron detectors, due to the possibility of low cost manufacturing and the potential for large areas. Polycrystalline CdTe is found to be an excellent material for thin film charged particle detectors—an integral component of a thin film neutron detector. The devices presented here are characterized in terms of their response to alpha and gamma radiation. Individual alpha particles are detected with an intrinsic efficiency of >80%, while the devices are largely insensitive to gamma rays, which is desirable so that the detector does not give false positive counts from gamma rays. The capacitance-voltage behavior of the devices is studied and correlated to the response due to alpha radiation. When coupled with a boron-based neutron converting material, the CdTe detectors are capable of detecting thermal neutrons.

  3. Space processing of electronic materials. [determining ther themal conductivity of mercury cadmium tellurides and furnace design

    Science.gov (United States)

    Workman, G. L.; Holland, L. R.

    1981-01-01

    The relative values of thermal conductivity of solid and liquid HgCdTe are critically important in the design configuration of the furnaces used for Bridgman crystal growth. The thermal diffusivity of the material is closely linked to the conductivity by the defining relation D = k/rho c, where D is the diffusivity, K is the thermal conductivity, rho is the density, and c is the specific heat. The use of transient and periodic heating approaches to measure the diffusivity are explored. A system for securing and extracting heat from silica or glass tubes under high C vacuum conditions is described.

  4. Next Generation Semiconductor-Based Radiation Detectors Using Cadmium Magnesium Telluride

    Energy Technology Data Exchange (ETDEWEB)

    Trivedi, Sudhir B [Brimrose Technology Corporation, Sparks Glencoe, MD (United States); Kutcher, Susan W [Brimrose Technology Corporation, Sparks Glencoe, MD (United States); Palsoz, Witold [Brimrose Technology Corporation, Sparks Glencoe, MD (United States); Berding, Martha [SRI International, Menlo Park, CA (United States); Burger, Arnold [Brimrose Technology Corporation, Sparks Glencoe, MD (United States)

    2014-11-17

    The primary objective of Phase I was to perform extensive studies on the purification, crystal growth and annealing procedures of CdMgTe to gain a clear understanding of the basic material properties to enable production of detector material with performance comparable to that of CdZnTe. Brimrose utilized prior experience in the growth and processing of II-VI crystals and produced high purity material and good quality single crystals of CdMgTe. Processing techniques for these crystals including annealing, mechanical and chemical polishing, surface passivation and electrode fabrication were developed. Techniques to characterize pertinent electronic characteristics were developed and gamma ray detectors were fabricated. Feasibility of the development of comprehensive defect modeling in this new class of material was demonstrated by our partner research institute SRI International, to compliment the experimental work. We successfully produced a CdMgTe detector that showed 662 keV gamma response with energy resolution of 3.4% (FWHM) at room temperature, without any additional signal correction. These results are comparable to existing CdZnTe (CZT) technology using the same detector size and testing conditions. We have successfully demonstrated detection of gamma-radiation from various isotopes/sources, using CdMgTe thus clearly proving the feasibility that CdMgTe is an excellent, low-cost alternative to CdZnTe.

  5. Tellurium vacancy in cadmium telluride revisited: size effects in the electronic properties

    OpenAIRE

    Menéndez-Proupin, E.; Orellana, W.

    2015-01-01

    The quantum states and thermodynamical properties of the Te vacancy in CdTe are addressed by first principles calculations, including the supercell size and quasiparticle corrections. It is shown that the 64-atoms supercell calculation is not suitable to model the band structure of the isolated Te vacancy. This problem can be solved with a larger 216-atoms supercell, where the band structure of the defect seems to be a perturbation of that of the perfect crystal. It is interesting to note tha...

  6. Polycrystalline thin film cadmium telluride n-i-p solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Meyers, P.V. (Ametek, Inc., Harleysville, PA (USA))

    1990-06-01

    This paper discusses experiments and analyses of technical, economic and environmental issues relating to CdTe n-i-p solar cells and their potential to satisfy the DOE PV program goals. The basic cell structure is CdS-CdTe-ZnTe. Included is an experimental and theoretical study of the operation of these devices. Experiments related to deposition of the CdS and ZnTe layers, cascaded solar cells, and module fabrication are described. Manufacturing issues relating to costs, worker safety, and environmental security are discussed. 40 refs., 25 figs., 16 tabs.

  7. Properties of RF sputtered cadmium telluride (CdTe) thin films: Influence of deposition pressure

    Science.gov (United States)

    Kulkarni, R. R.; Pawbake, A. S.; Waykar, R. G.; Rondiya, S. R.; Jadhavar, A. A.; Pandharkar, S. M.; Karpe, S. D.; Diwate, K. D.; Jadkar, S. R.

    2016-04-01

    Influence of deposition pressure on structural, morphology, electrical and optical properties of CdTe thin films deposited at low substrate temperature (100°C) by RF magnetron sputtering was investigated. The formation of CdTe was confirmed by low angle XRD and Raman spectroscopy. The low angle XRD analysis revealed that the CdTe films have zinc blende (cubic) structure with crystallites having preferred orientation in (111) direction. Raman spectra show the longitudinal optical (LO) phonon mode peak ˜ 165.4 cm-1 suggesting high quality CdTe film were obtained over the entire range of deposition pressure studied. Scanning electron microscopy analysis showed that films are smooth, homogenous, and crack-free with no evidence of voids. The EDAX data revealed that CdTe films deposited at low deposition pressure are high-quality stoichiometric. However, for all deposition pressures, films are rich in Cd relative to Te. The UV-Visible spectroscopy analysis show the blue shift in absorption edge with increasing the deposition pressure while the band gap show decreasing trend. The highest electrical conductivity was obtained for the film deposited at deposition pressure 1 Pa which indicates that the optimized deposition pressure for our sputtering unit is 1 Pa. Based on the experimental results, these CdTe films can be useful for the application in the flexible solar cells and other opto-electronic devices.

  8. An ultrasensitive method for the determination of melamine using cadmium telluride quantum dots as fluorescence probes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiafei; Li, Jin; Kuang, Huiyan; Feng, Lei; Yi, Shoujun; Xia, Xiaodong; Huang, Haowen [School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201 (China); Key Laboratory of Theoretical Chemistry and Molecular Simulation of Ministry of Education of China, Hunan University of Science and Technology, Xiangtan 411201 (China); Chen, Yong; Tang, Chunran [School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201 (China); Zeng, Yunlong, E-mail: yunlongzeng1955@126.com [School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201 (China); Key Laboratory of Theoretical Chemistry and Molecular Simulation of Ministry of Education of China, Hunan University of Science and Technology, Xiangtan 411201 (China); State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China)

    2013-11-13

    Graphical abstract: Melamine takes place of the TGA on the surface of TGA-CdTe QDs with negative charge to form melamine coated QDs changing the surface charge of the QDs, resulting the fluorescence quenched as the QDs aggregation occurred by electrostatic attraction of the two opposite charged nanocrystals. -- Highlights: •An ultrasensitive and selective method for the determination of melamine was developed at pH 11.0. •The selectivity of the method was improved. •The sensitivity of the method enhanced obviously as the CdTe QDs have higher QYs at pH 11. •The sensitivity and linear range for the analysis are size dependent using QDs PL probes. •Melamine takes the place of TGA resulting fluorescence quenched of QDs. -- Abstract: An ultrasensitive and simple method for the determination of melamine was developed based on the fluorescence quenching of thioglycolic acid (TGA) capped CdTe quantum dots (QDs) at pH 11.0. In strong alkaline aqueous solution, the selectivity of the method has been greatly improved due to most heavy metal ions show no interference as they are in the precipitation form or in their anion form. Furthermore, CdTe quantum dots have higher quantum yields at higher pH. The method has a wider concentration range and lower detection limit. The influence factors on the determination of melamine were investigated and the optimum conditions were determined. Under optimum conditions, the fluorescence intensity change of TGA coated CdTe quantum dots was linearly proportional to melamine over a concentration range from 1.0 × 10{sup −11} to 1.0 × 10{sup −5} mol L{sup −1} with a correlation coefficient of 0.9943 and a detection limit of 5 × 10{sup −12} mol L{sup −1}. The mechanism of fluorescence quenching of the QDs has been proposed based on the infrared spectroscopy information and electrophoresis experiments in presence of melamine under alkaline condition. The proposed method was employed to detect trace melamine in milk powder and pet feeds with satisfactory results.

  9. Contribution to cadmium telluride characterizations by ion beams and nuclear detection

    International Nuclear Information System (INIS)

    A short survey of the thermodynamics and crystal growth of CdTe is followed by the description of high mass and depth resolution Rutherford backscattering (RBS) with light and heavy ions. Energy losses in CdTe have been measured. Analysis of CdTe surfaces by RBS, SIMS, ellipsometry have also been performed. Diffused, implanted, or simply contacted CdTe junctions have been analyzed and then investigated as gamma spectrometers. The problem of polarization was specially studied

  10. Characterization of metal contacts on and surfaces of cadmium zinc telluride

    CERN Document Server

    Bürger, A; Chattopadhyay, K; Shi, D; Morgan, S H; Collins, W E; James, R B

    1999-01-01

    In the past several years significant progress has been made in building a database of physical properties for detector quality Cd sub x Zn sub 1 sub - sub x Te (CZT) (x=0.1-0.2) crystal material. CZT's high efficiency combined with its room temperature operation make the material an excellent choice for imaging and spectroscopy in the 10-200 keV energy range. For detector grade material, superior crystallinity and high bulk resistivity are required. The surface preparation during the detector fabrication plays a vital role in determining the contact characteristics and the surface leakage current, which are often the dominant factors influencing its performance. This paper presents a surface and contact characterization study aimed at establishing the effects of the surface preparation steps prior to contacting (polishing and chemical etching), the choice of the metal and contact deposition technique, and the surface oxidation process. A photoconductivity mapping technique is used for studying the effects of...

  11. Prognostic evaluation in obese patients using a dedicated multipinhole cadmium-zinc telluride SPECT camera.

    Science.gov (United States)

    De Lorenzo, Andrea; Peclat, Thais; Amaral, Ana Carolina; Lima, Ronaldo S L

    2016-02-01

    The purpose of this study is to evaluate the prognostic value of myocardial perfusion SPECT obtained in CZT cameras (CZT-SPECT) with multipinhole collimation in obese patients. CZT-SPECT may be technically challenging in the obese, and its prognostic value remains largely unknown. Patients underwent single-day, rest/stress (supine and prone) imaging. Images were visually inspected and graded as poor, fair or good/excellent. Summed stress and difference scores (SSS and SDS, respectively) were converted into percentages of total perfusion defect and of ischemic defect by division by the maximum possible score. Obesity was defined as a body mass index (BMI) ≥ 30 kg/m(2) and classified as class I (BMI 30-34.9 kg/m(2)), II (BMI 35-39.9 kg/m(2)), or III (BMI ≥ 40 kg/m(2)). Patients were followed-up by telephone interview for the occurrence of all-cause death, myocardial infarction or revascularization. A Cox proportional hazards analysis was used to assess the independent predictors of death. Among 1396 patients, 365 (26.1 %) were obese (mean BMI 33.9 ± 3.6; 17.5 % class I, 3.4 % class II, and 3.4 % class III). Image quality was good/excellent in 94.5 % of the obese patients. The annualized mortality rates were not significantly different among obese and non-obese patients, being image quality. PMID:26424491

  12. Microwave photoconductivity of cadmium telluride doped by gallium studied at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Marinin, Alexander; Radychev, Nikolay; Novikov, Gennadii; Gapanovich, Mikhail [IPCP RAS, Chernogolovka, Moscow (Russian Federation)

    2009-07-01

    The number of charges reaching the electrodes is a key parameter for detector quality characteristics. Solid solutions of CdTe-GaTe are considered as a perspective medium for X-ray detection. The kinetics of photogenerated charges was studied at different temperatures and for different doping concentrations. The samples were made by CdTe and GaTe vacuum sintering. The sintering temperature and duration were 1010 K and 300 h, respectively. The microwave photoconductivity (f=36 GHz) was investigated. The temporal resolution of the experimental facility was decreased to 5 ns. Investigations were made in a wide temperature range, T=140-295 K. A nitrogen laser was used for photoexcitation. Generally, the experimental curves of the photoresponse P(t) consist of fast and slow components after switching of the laser light. The temperature and the Ga content were found to influence the form, amplitude and characteristical decay time of P(t) considerably. The photoresponse decay analysis shows that a self-compensation effect is present and this effect results in a decrease of the depth of traps. The active medium parameters take a turn for the better by this effect.

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

    Energy Technology Data Exchange (ETDEWEB)

    Rohatgi, A.; Sudharsanan, R.; Ringel, S. (Georgia Inst. of Tech., Atlanta, GA (United States))

    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.

  14. Finite solid angle correction factors and efficiencies for cadmium telluride detectors

    International Nuclear Information System (INIS)

    Finite solid angle correction factors and absolute detection efficiencies of the CdTe detectors of right circular cylindrical geometry for point sources placed on the axis of the detector, has been calculated for γ-ray energies from 100keV to 10MeV, taking into account various source to detector distances, ranging from 1 to 10cm. CdTe detectors of several area between 0.12 and 2.5cm2 of various thickness were considered

  15. Electronic Band Structure and Optical Characteristics of Quantum-Size Cadmium Telluride Crystals in Glass Films

    Science.gov (United States)

    Potter, Barrett George, Jr.

    Low-dimensional semiconductor structures now occupy a position of central importance with regard to the understanding and application of the basic physics of quantum confinement. Isolated II-VI semiconductor crystals embedded in transparent, insulating matrices represent a convenient medium for the study of quantum-size effects on the electronic and optical properties of compound semiconductors. The present study simultaneously examines finite crystal size-related shifts in the energies of optical transitions originating from states located at two different critical points of the zincblende Brillouin zone of CdTe. Using a versatile, dual source, R.F.-sputtering technique, CdTe-glass composite thin films have been produced possessing average crystal sizes ranging from 24 to 125 A in films containing 5 vol% semiconductor as determined by cross-sectional, transmission electron microscopy. Previously unattainable control over such microstructural characteristics as volume fraction and crystalline phase distribution throughout the matrix have been demonstrated using the sequential sputtering process. Analysis of quantum-size induced transition energy shifts, monitored by optical absorption, indicates the persistence of significant Coulomb interactions between carriers at the T-point of CdTe in crystallite sizes 0.3 times the size of the bulk exciton. L-point transition energy shifts support the existence of two-dimensional bound electron-hole pair states whose center-of-mass motion is confined within the potential well. The influence of finite crystal size distribution width on the interpretation of quantum confinement effects in these materials was also analyzed using a numerical integration technique. Findings substantiate the relative dominance of inhomogeneous broadening effects over homogeneous broadening in determining the observed absorption lineshape of the polydisperse collection of crystallites. This does not, however, explain an apparent saturation of the energy shifts exhibited by both Gamma- and L-point transitions at very small sizes. Such behavior is likely due to an increasing dominance of interface-related modifications to the bulk semiconductor crystalline and electronic structure. Insight into the chemical state of the semiconductor constituents is obtained using x-ray photoelectron spectroscopy with particular emphasis on the Te 3d_{5/2 } photoelectron peak. Spectrum components of this energy region, associated with the oxide, semiconductor and matrix, are monitored with heat-treatment of the films.

  16. Ion beam etching system for mercury cadmium telluride and III-V compound semiconductors

    International Nuclear Information System (INIS)

    This paper describes a laboratory built ion beam etching system and its performance when used for etching Hg1-xCdxTe, GaAs and InP. The etching system provides a means for forming device mesas on a wide range of semiconductors without having to resort to wet chemical etches. The system uses a Kaufmann ion source, a rotating platform and two flow controllers to allow the variation of gas ratios and flows

  17. Determination of deep levels in semi-insulating cadmium telluride by thermally stimulated current measurements

    International Nuclear Information System (INIS)

    Thermally stimulated current (TSC) measurements have been performed in high resistivity (rho approximately 107ohms.cm) CdTe γ-ray detectors between 35 and 300K. The TSC curves have been analyzed by different methods, including those taking into account the retrapping of the carriers. The trap characteristics have been determined; especially three levels located at E(v)+0.13eV, E(v)+0.30eV and E(c)-0.55eV have been investigated

  18. Analysis of the traveling heater method for the growth of cadmium telluride

    Science.gov (United States)

    Peterson, Jeffrey H.; Fiederle, Michael; Derby, Jeffrey J.

    2016-11-01

    We discuss the development and implementation of a comprehensive mathematical model for the traveling heater method (THM) that is formulated to realistically represent the interactions of heat and species transport, fluid flow, and interfacial dissolution and growth under conditions of local thermodynamic equilibrium and steady-state growth. We examine the complicated interactions among zone geometry, continuum transport, phase change, and fluid flow driven by buoyancy. Of particular interest and importance is the formation of flow structures in the liquid zone of the THM that arise from the same physical mechanism as lee waves in atmospheric flows and demonstrate the same characteristic Brunt-Väisälä scaling. We show that flow stagnation and reversal associated with lee-wave formation are responsible for the accumulation of tellurium and supercooled liquid near the growth interface, even when the lee-wave vortex is not readily apparent in the overall flow structure. The supercooled fluid is posited to result in morphological instability at growth rates far below the limit predicted by the classical criterion by Tiller et al. for constitutional supercooling.

  19. Decentalized solar photovoltaic energy systems

    Energy Technology Data Exchange (ETDEWEB)

    Krupka, M. C.

    1980-09-01

    Environmental data for decentralized solar photovoltaic systems have been generated in support of the Technology Assessment of Solar Energy Systems program (TASE). Emphasis has been placed upon the selection and use of a model residential photovoltaic system to develop and quantify the necessary data. The model consists of a reference home located in Phoenix, AZ, utilizing a unique solar cell array-roof shingle combination. Silicon solar cells, rated at 13.5% efficiency at 28/sup 0/C and 100 mW/cm/sup 2/ (AMI) insolation are used to generate approx. 10 kW (peak). An all-electric home is considered with lead-acid battery storage, dc-ac inversion and utility backup. The reference home is compared to others in regions of different insolation. Major material requirements, scaled to quad levels of end-use energy include significant quantities of silicon, copper, lead, antimony, sulfuric acid and plastics. Operating residuals generated are negligible with the exception of those from the storage battery due to a short (10-year) lifetime. A brief general discussion of other environmental, health, and safety and resource availability impacts is presented. It is suggested that solar cell materials production and fabrication may have the major environmental impact when comparing all facets of photovoltaic system usage. Fabrication of the various types of solar cell systems involves the need, handling, and transportation of many toxic and hazardous chemicals with attendant health and safety impacts. Increases in production of such materials as lead, antimony, sulfuric acid, copper, plastics, cadmium and gallium will be required should large scale usage of photovoltaic systems be implemented.

  20. Core-Shell Nanopillar Array Solar Cells using Cadmium Sulfide Coating on Indium Phosphide Nanopillars

    OpenAIRE

    Tu, Bor-An Clayton

    2013-01-01

    This thesis presents a new strategy to fabricate nanostructured indium phosphide and cadmium sulfide photovoltaics. The cells are formed by chemical bath deposition (electroless deposition) of cadmium sulfide onto indium phosphide nanopillar arrays grown by selective-area metalorganic chemical vapor deposition. Characterizations through electrical and optical measurements show that the devices consisting of p-InP core and CdS shell have a conversion efficiency, open circuit voltage, short cir...

  1. Method of Creating Micro-scale Silver Telluride Grains Covered with Bismuth Nanoparticles

    Science.gov (United States)

    Kim, Hyun-Jung (Inventor); Choi, Sang Hyouk (Inventor); King, Glen C. (Inventor); Park, Yeonjoon (Inventor); Lee, Kunik (Inventor)

    2014-01-01

    Provided is a method of enhancing thermoelectric performance by surrounding crystalline semiconductors with nanoparticles by contacting a bismuth telluride material with a silver salt under a substantially inert atmosphere and a temperature approximately near the silver salt decomposition temperature; and recovering a metallic bismuth decorated material comprising silver telluride crystal grains.

  2. Organic photovoltaics

    Science.gov (United States)

    Demming, Anna; Krebs, Frederik C.; Chen, Hongzheng

    2013-12-01

    Energy inflation, the constant encouragement to economize on energy consumption and the huge investments in developing alternative energy resources might seem to suggest that there is a global shortage of energy. Far from it, the energy the Sun beams on the Earth each hour is equivalent to a year's supply, even at our increasingly ravenous rate of global energy consumption [1]. But it's not what you have got it's what you do with it. Hence the intense focus on photovoltaic research to find more efficient ways to harness energy from the Sun. Recently much of this research has centred on organic solar cells since they offer simple, low-cost, light-weight and large-area flexible photovoltaic structures. This issue with guest editors Frederik C Krebs and Hongzheng Chen focuses on some of the developments at the frontier of organic photovoltaic technology. Improving the power conversion efficiency of organic photovoltaic systems, while maintaining the inherent material, economic and fabrication benefits, has absorbed a great deal of research attention in recent years. Here significant progress has been made with reports now of organic photovoltaic devices with efficiencies of around 10%. Yet operating effectively across the electromagnetic spectrum remains a challenge. 'The trend is towards engineering low bandgap polymers with a wide optical absorption range and efficient hole/electron transport materials, so that light harvesting in the red and infrared region is enhanced and as much light of the solar spectrum as possible can be converted into an electrical current', explains Mukundan Thelakkat and colleagues in Germany, the US and UK. In this special issue they report on how charge carrier mobility and morphology of the active blend layer in thin film organic solar cells correlate with device parameters [2]. The work contributes to a better understanding of the solar-cell characteristics of polymer:fullerene blends, which form the material basis for some of the most

  3. Photovoltaics: New opportunities for utilities

    Energy Technology Data Exchange (ETDEWEB)

    1991-07-01

    This publication presents information on photovoltaics. The following topics are discussed: Residential Photovoltaics: The New England Experience Builds Confidence in PV; Austin's 300-kW Photovoltaic Power Station: Evaluating the Breakeven Costs; Residential Photovoltaics: The Lessons Learned; Photovoltaics for Electric Utility Use; Least-Cost Planning: The Environmental Link; Photovoltaics in the Distribution System; Photovoltaic Systems for the Rural Consumer; The Issues of Utility-Intertied Photovoltaics; and Photovoltaics for Large-Scale Use: Costs Ready to Drop Again.

  4. Photovoltaic solar concentrator

    Energy Technology Data Exchange (ETDEWEB)

    Nielson, Gregory N.; Cruz-Campa, Jose Luis; Okandan, Murat; Resnick, Paul J.; Sanchez, Carlos Anthony; Clews, Peggy J.; Gupta, Vipin P.

    2015-09-08

    A process including forming a photovoltaic solar cell on a substrate, the photovoltaic solar cell comprising an anchor positioned between the photovoltaic solar cell and the substrate to suspend the photovoltaic solar cell from the substrate. A surface of the photovoltaic solar cell opposite the substrate is attached to a receiving substrate. The receiving substrate may be bonded to the photovoltaic solar cell using an adhesive force or a metal connecting member. The photovoltaic solar cell is then detached from the substrate by lifting the receiving substrate having the photovoltaic solar cell attached thereto and severing the anchor connecting the photovoltaic solar cell to the substrate. Depending upon the type of receiving substrate used, the photovoltaic solar cell may be removed from the receiving substrate or remain on the receiving substrate for use in the final product.

  5. Organic photovoltaics

    Science.gov (United States)

    Demming, Anna; Krebs, Frederik C.; Chen, Hongzheng

    2013-12-01

    Energy inflation, the constant encouragement to economize on energy consumption and the huge investments in developing alternative energy resources might seem to suggest that there is a global shortage of energy. Far from it, the energy the Sun beams on the Earth each hour is equivalent to a year's supply, even at our increasingly ravenous rate of global energy consumption [1]. But it's not what you have got it's what you do with it. Hence the intense focus on photovoltaic research to find more efficient ways to harness energy from the Sun. Recently much of this research has centred on organic solar cells since they offer simple, low-cost, light-weight and large-area flexible photovoltaic structures. This issue with guest editors Frederik C Krebs and Hongzheng Chen focuses on some of the developments at the frontier of organic photovoltaic technology. Improving the power conversion efficiency of organic photovoltaic systems, while maintaining the inherent material, economic and fabrication benefits, has absorbed a great deal of research attention in recent years. Here significant progress has been made with reports now of organic photovoltaic devices with efficiencies of around 10%. Yet operating effectively across the electromagnetic spectrum remains a challenge. 'The trend is towards engineering low bandgap polymers with a wide optical absorption range and efficient hole/electron transport materials, so that light harvesting in the red and infrared region is enhanced and as much light of the solar spectrum as possible can be converted into an electrical current', explains Mukundan Thelakkat and colleagues in Germany, the US and UK. In this special issue they report on how charge carrier mobility and morphology of the active blend layer in thin film organic solar cells correlate with device parameters [2]. The work contributes to a better understanding of the solar-cell characteristics of polymer:fullerene blends, which form the material basis for some of the most

  6. Cadmium toxicity and treatment.

    Science.gov (United States)

    Bernhoft, Robin A

    2013-01-01

    Cadmium is a heavy metal of considerable toxicity with destructive impact on most organ systems. It is widely distributed in humans, the chief sources of contamination being cigarette smoke, welding, and contaminated food and beverages. Toxic impacts are discussed and appear to be proportional to body burden of cadmium. Detoxification of cadmium with EDTA and other chelators is possible and has been shown to be therapeutically beneficial in humans and animals when done using established protocols.

  7. Cadmium Toxicity and Treatment

    Directory of Open Access Journals (Sweden)

    Robin A. Bernhoft

    2013-01-01

    Full Text Available Cadmium is a heavy metal of considerable toxicity with destructive impact on most organ systems. It is widely distributed in humans, the chief sources of contamination being cigarette smoke, welding, and contaminated food and beverages. Toxic impacts are discussed and appear to be proportional to body burden of cadmium. Detoxification of cadmium with EDTA and other chelators is possible and has been shown to be therapeutically beneficial in humans and animals when done using established protocols.

  8. Cadmium Toxicity and Treatment

    OpenAIRE

    Bernhoft, Robin A.

    2013-01-01

    Cadmium is a heavy metal of considerable toxicity with destructive impact on most organ systems. It is widely distributed in humans, the chief sources of contamination being cigarette smoke, welding, and contaminated food and beverages. Toxic impacts are discussed and appear to be proportional to body burden of cadmium. Detoxification of cadmium with EDTA and other chelators is possible and has been shown to be therapeutically beneficial in humans and animals when done using established proto...

  9. Origin of anomalous anharmonic lattice dynamics of lead telluride

    CERN Document Server

    Shiga, Takuma; Hori, Takuma; Delaire, Olivier; Shiomi, Junichiro

    2015-01-01

    The origin of the anomalous anharmonic lattice dynamics of lead telluride is investigated using molecular dynamics simulations with interatomic force constants (IFCs) up to quartic terms obtained from first principles. The calculations reproduce the peak asymmetry of the radial distribution functions and the double peaks of transverse optical phonon previously observed with neutron diffraction and scattering experiments. They are identified to be due to the extremely large nearest-neighbor cubic IFCs in the [100] direction. The outstanding strength of the nearest-neighbor cubic IFCs relative to the longer-range ones explains the reason why the distortion in the radial distribution function is local.

  10. The heat capacity of zinc and cadmium chalcogenides (ZnTe, CdSe, and CdTe)

    International Nuclear Information System (INIS)

    Heat capacity of zinc telluride, cadmium selenide and telluride are measured by the calorimetry method at 370-640 K (ZnTe) and 500-760 K (CdSe, CdTe). Analysis of literature data on heat capacity of the above-mentioned solid solutions at temperatures in excess of 298 K is carried out. On the basis of the results obtained and most dependable literature data on heat capacity of the compounds for temperature ranges of 220-1500 K (ZnTe, CdSe) and 220-1300 K (CdTe) new equations of heat capacity temperature dependence are suggested and thermodynamic functions of the compounds are calculated

  11. Kelvin probe studies of cesium telluride photocathode for AWA photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    Wisniewski, Eric E., E-mail: ewisniew@anl.gov [High Energy Physics Division, Argonne National Laboratory, 9700 S. Cass, Lemont, IL 60439 (United States); Physics Department, Illinois Institute of Technology, 3300 South Federal Street, Chicago, IL 60616 (United States); Velazquez, Daniel [High Energy Physics Division, Argonne National Laboratory, 9700 S. Cass, Lemont, IL 60439 (United States); Physics Department, Illinois Institute of Technology, 3300 South Federal Street, Chicago, IL 60616 (United States); Yusof, Zikri, E-mail: zyusof@hawk.iit.edu [High Energy Physics Division, Argonne National Laboratory, 9700 S. Cass, Lemont, IL 60439 (United States); Physics Department, Illinois Institute of Technology, 3300 South Federal Street, Chicago, IL 60616 (United States); Spentzouris, Linda; Terry, Jeff [Physics Department, Illinois Institute of Technology, 3300 South Federal Street, Chicago, IL 60616 (United States); Sarkar, Tapash J. [Rice University, 6100 Main, Houston, TX 77005 (United States); Harkay, Katherine [Accelerator Science Division, Argonne National Laboratory, 9700 S. Cass, Lemont, IL 60439 (United States)

    2013-05-21

    Cesium telluride is an important photocathode as an electron source for particle accelerators. It has a relatively high quantum efficiency (>1%), is sufficiently robust in a photoinjector, and has a long lifetime. This photocathode is grown in-house for a new Argonne Wakefield Accelerator (AWA) beamline to produce high charge per bunch (≈50nC) in a long bunch train. Here, we present a study of the work function of cesium telluride photocathode using the Kelvin probe technique. The study includes an investigation of the correlation between the quantum efficiency and the work function, the effect of photocathode aging, the effect of UV exposure on the work function, and the evolution of the work function during and after photocathode rejuvenation via heating. -- Highlights: ► The correlation between Quantum Efficiency (QE) and work function. ► How QE and work function evolve together. ► Rejuvenation of the photocathode via heating and the effect on work function. ► The effects on the work function due to exposure to UV light.

  12. Analysis of energy production with different photovoltaic technologies in the Colombian geography

    International Nuclear Information System (INIS)

    This research has analyzed the photovoltaic technologies, Polycrystalline silicon, Monocrystalline Silicon, GIS, Cadmium Tellurium and Amorphous Silicon; in eight cities of the Colombian territory, in order to obtain a clear idea of what is the most appropriate for each city or region studied. PVsyst simulation software has been used to study in detail each photovoltaic technology, for an installed capacity of 100kW knowing the specific data of losses by temperature, mismatch, efficiency, wiring, angle inclination of the arrangement, among others

  13. Analysis of energy production with different photovoltaic technologies in the Colombian geography

    Science.gov (United States)

    Muñoz, Y.; Zafra, D.; Acevedo, V.; Ospino, A.

    2014-06-01

    This research has analyzed the photovoltaic technologies, Polycrystalline silicon, Monocrystalline Silicon, GIS, Cadmium Tellurium and Amorphous Silicon; in eight cities of the Colombian territory, in order to obtain a clear idea of what is the most appropriate for each city or region studied. PVsyst simulation software has been used to study in detail each photovoltaic technology, for an installed capacity of 100kW knowing the specific data of losses by temperature, mismatch, efficiency, wiring, angle inclination of the arrangement, among others

  14. Abnormal physics of group-II telluride system:valence contribution of d electrons

    Institute of Scientific and Technical Information of China (English)

    Duan He; Dong You-Zhong; Huang Yan; Chen Xiao-Shuang

    2011-01-01

    The physical trend of group-II tellurides is unexpected and contrary to the conventional wisdom. The present firstprinciples calculations give fundamental insights into the extent to which group-II telluride compounds present special properties upon mixing the d valence character.Our results provide explanations for the unexpected experimental observations based on the abnormal binding ordering of metal d electrons and their strong perturbation to the band edge states. The insights into the binary tellurides are useful for the study and control of the structural and chemical perturbation in their ternary alloys and heterostructures.

  15. Effect of metallic coatings on thermoelectric properties of lead telluride films

    Energy Technology Data Exchange (ETDEWEB)

    Ukhlinov, G.A.; Lakhno, I.G. (Moskovskij Inst. Ehlektronnoj Tekhniki (USSR))

    1984-05-01

    Effect of sprayed coatings of different metals on thermoelectric properties of lead telluride films was investigated. The basic films were prepared by the method of vacuum thermal evaporation of sample of stoichiometric lead telluride at 5x10/sup -4/ Pa residual pressure on mica (muscovite) sublayer at 330-350 deg C and approximately 10 nm/s deposition rate. It was established that fine coatings of copper, silver and gold modify sufficiently electric properties of lead telluride films. The effect is conditioned mainly by decoration and electric shunting of grain boundaries by metal island, which removes the contribution of grain boundaries to film electric conductivity.

  16. Zinc and cadmium monosalicylates

    Energy Technology Data Exchange (ETDEWEB)

    Kharitonov, Yu.Ya.; Tujebakhova, Z.K. (Moskovskij Khimiko-Tekhnologicheskij Inst. (USSR))

    1984-06-01

    Zinc and cadmium monosalicylates of the composition MSal, where M-Zn or Cd, Sal - twice deprotonated residue of salicylic acid O-HOC/sub 6/H/sub 4/COOH (H/sub 2/Sal), are singled out and characterized. When studying thermograms, thermogravigrams, IR absorption spectra, roentgenograms of cadmium salicylate compounds (Cd(OC/sub 6/H/sub 4/COO) and products of their thermal transformations, the processes of thermal decomposition of the compounds have been characterized. The process of cadmium monosalicylate decomposition takes place in one stage. Complete loss of salicylate acido group occurs in the range of 320-460 deg. At this decomposition stage cadmium oxide is formed. A supposition is made that cadmium complex has tetrahedral configuration, at that, each salicylate group plays the role of tetradentate-bridge ligand. The compound evidently has a polymer structure.

  17. Aerosol Spray Pyrolysis Synthesis of CZTS Nanostructures for Photovoltaic Applications

    OpenAIRE

    Exarhos, Stephen

    2015-01-01

    As harmful effects caused by the extraction, purification, and combustion of natural resources for energy generation become more clearly understood, the need for economically competitive renewable energy becomes more desirable. Solar energy- generation is a technologically feasible method, though its primary drawback is cost. Traditional single-crystal silicon-based photovoltaics are too expensive to compete with nonrenewable energy generation, while alternative materials such as cadmium tell...

  18. A photovoltaic module

    OpenAIRE

    KREBS Frederik C.; Sommer-Larsen, Peter

    2013-01-01

    The present invention relates to a photovoltaic module comprising a carrier substrate, said carrier substrate carrying a purely printed structure comprising printed positive and negative module terminals, a plurality of printed photovoltaic cell units each comprising one or more printed photovoltaic cells, wherein the plurality of printed photovoltaic cell units are electrically connected in series between the positive and the negative module terminals such that any two neighbouring photovolt...

  19. Thermionic photovoltaic energy converter

    Science.gov (United States)

    Chubb, D. L. (Inventor)

    1985-01-01

    A thermionic photovoltaic energy conversion device comprises a thermionic diode mounted within a hollow tubular photovoltaic converter. The thermionic diode maintains a cesium discharge for producing excited atoms that emit line radiation in the wavelength region of 850 nm to 890 nm. The photovoltaic converter is a silicon or gallium arsenide photovoltaic cell having bandgap energies in this same wavelength region for optimum cell efficiency.

  20. The performance of a combined solar photovoltaic (PV) and thermoelectric generator (TEG) system

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Nielsen, Kaspar Kirstein

    2015-01-01

    The performance of a combined solar photovoltaic (PV) and thermoelectric generator (TEG) system is examined using an analytical model for four different types of commercial PVs and a commercial bismuth telluride TEG. The TEG is applied directly on the back of the PV, so that the two devices have...... efficiency of the TEG. For c-Si, CIGS and CdTe PV cells the combined system produces a lower power and has a lower efficiency than the PV alone, whereas for an a-Si cell the total system performance may be slightly increased by the TEG....

  1. Photovoltaic device and method

    Science.gov (United States)

    Cleereman, Robert; Lesniak, Michael J.; Keenihan, James R.; Langmaid, Joe A.; Gaston, Ryan; Eurich, Gerald K.; Boven, Michelle L.

    2015-11-24

    The present invention is premised upon an improved photovoltaic device ("PVD") and method of use, more particularly to an improved photovoltaic device with an integral locator and electrical terminal mechanism for transferring current to or from the improved photovoltaic device and the use as a system.

  2. High density photovoltaic

    Energy Technology Data Exchange (ETDEWEB)

    Haigh, R.E.; Jacobson, G.F.; Wojtczuk, S. [Spire Corp., Bedford, MA (United States)

    1997-10-14

    Photovoltaic technology can directly generate high voltages in a solid state material through the series interconnect of many photovoltaic diodes. We are investigating the feasibility of developing an electrically isolated, high-voltage power supply using miniature photovoltaic devices that convert optical energy to electrical energy.

  3. Current topics in photovoltaics

    International Nuclear Information System (INIS)

    This book contains papers on current research in photovoltaics. Areas include: outdoor spectral odor radiation variations and their relationship to photovoltaic device performance, numerical modeling for analysis and design of solar cells, radiation damage mechanisms in GaAs and Si solar cells, and health and safety issues in the manufacturing of photovoltaic cells

  4. Photovoltaic device and method

    Science.gov (United States)

    Cleereman, Robert J; Lesniak, Michael J; Keenihan, James R; Langmaid, Joe A; Gaston, Ryan; Eurich, Gerald K; Boven, Michelle L

    2015-01-27

    The present invention is premised upon an improved photovoltaic device ("PVD") and method of use, more particularly to an improved photovoltaic device with an integral locator and electrical terminal mechanism for transferring current to or from the improved photovoltaic device and the use as a system.

  5. High efficiency cadmium telluride and zinc telluride based thin-film solar cells. Annual subcontract report, 1 March 1990--28 February 1992

    Energy Technology Data Exchange (ETDEWEB)

    Rohatgi, A.; Sudharsanan, R.; Ringel, S.A.; Chou, H.C. [Georgia Inst. of Tech., Atlanta, GA (United States)

    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.

  6. Electrochemical Studies of Lead Telluride Behavior in Acidic Nitrate Solutions

    Directory of Open Access Journals (Sweden)

    Rudnik E.

    2015-04-01

    Full Text Available Electrochemistry of lead telluride stationary electrode was studied in nitric acid solutions of pH 1.5-3.0. E-pH diagram for Pb-Te-H2O system was calculated. Results of cyclic voltammetry of Pb, Te and PbTe were discussed in correlation with thermodynamic predictions. Anodic dissolution of PbTe electrode at potential approx. -100÷50 mV (SCE resulted in tellurium formation, while above 300 mV TeO2 was mainly produced. The latter could dissolve to HTeO+2 under acidic electrolyte, but it was inhibited by increased pH of the bath.

  7. Tunable split-ring resonators using germanium telluride

    Science.gov (United States)

    Kodama, C. H.; Coutu, R. A.

    2016-06-01

    We demonstrate terahertz (THz) split-ring resonator (SRR) designs with incorporated germanium telluride (GeTe) thin films. GeTe is a chalcogenide that undergoes a nonvolatile phase change from the amorphous to crystalline state at approximately 200 °C, depending on the film thickness and stoichiometry. The phase change also causes a drop in the material's resistivity by six orders of magnitude. In this study, two GeTe-incorporated SRR designs were investigated. The first was an SRR made entirely out of GeTe and the second was a gold SRR structure with a GeTe film incorporated into the gap region of the split ring. These devices were characterized using THz time-domain spectroscopy and were heated in-situ to determine the change in the design operation with varying temperatures.

  8. Transparent ultraviolet photovoltaic cells.

    Science.gov (United States)

    Yang, Xun; Shan, Chong-Xin; Lu, Ying-Jie; Xie, Xiu-Hua; Li, Bing-Hui; Wang, Shuang-Peng; Jiang, Ming-Ming; Shen, De-Zhen

    2016-02-15

    Photovoltaic cells have been fabricated from p-GaN/MgO/n-ZnO structures. The photovoltaic cells are transparent to visible light and can transform ultraviolet irradiation into electrical signals. The efficiency of the photovoltaic cells is 0.025% under simulated AM 1.5 illumination conditions, while it can reach 0.46% under UV illumination. By connecting several such photovoltaic cells in a series, light-emitting devices can be lighting. The photovoltaic cells reported in this Letter may promise the applications in glass of buildings to prevent UV irradiation and produce power for household appliances in the future.

  9. Cadmium status in Egypt

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    It is inferred from these studies that releases of Cd are still increasing and it is recommended that measures must be taken to reduce emissions of cadmium. Any cadmium discharged into the Egyptian environment may move from one compartment to another at varying rates,resulting in an accumulation in compartments such as soils and biota. Such accumulation can be expected to increase with continued emissions,and attention should be given to all sources of cadmium, natural as well as anthropogenic especially in the industrial cities in Egypt. Cadmium present in sewage, as well as industrial effluent (also, other liquid and solid wastes) and sewage sludge will increase levels in soils and is xpected to contribute to dietary levels and body burdens. The current information indicates that such effects may have to be evaluated over long periods of time, possibly as long as 50 - 100 years.

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

    Science.gov (United States)

    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.

  11. Plausible Mechanisms of Cadmium Carcinogenesis

    Science.gov (United States)

    Cadmium is a transition metal and an ubiquitous environmental and industrial pollutant. Laboratory animal studies and epidemiological studies have shown that exposure to cadmium is associated with various organ toxicities and carcinogenic effects. Several national and internation...

  12. A photovoltaic module

    DEFF Research Database (Denmark)

    2013-01-01

    The present invention relates to a photovoltaic module comprising a carrier substrate, said carrier substrate carrying a purely printed structure comprising printed positive and negative module terminals, a plurality of printed photovoltaic cell units each comprising one or more printed...... photovoltaic cells, wherein the plurality of printed photovoltaic cell units are electrically connected in series between the positive and the negative module terminals such that any two neighbouring photovoltaic cell units are electrically connected by a printed interconnecting electrical conductor....... The carrier substrate comprises a foil and the total thickness of the photovoltaic module is below 500 [mu]m. Moreover, the nominal voltage level between the positive and the negative terminals is at least 5 kV DC....

  13. Cadmium absorption inhibitors for soil

    Energy Technology Data Exchange (ETDEWEB)

    Kitamura, S.

    1974-05-25

    Cadmium absorption by soil is one cause of soil pollution. Cadmium adsorption inhibitors were prepared by mixing alginic acid which contained brown algae (Ascophyllum nodosum) and an inorganic material, shell fossils. This mixture was highly effective in preventing cadmium absorption by the soil.

  14. Photovoltaic technology assessment

    Energy Technology Data Exchange (ETDEWEB)

    Backus, C.E.

    1981-01-01

    After a brief review of the history of photovoltaic devices and a discussion of the cost goals set for photovoltaic modules, the status of photovoltaic technology is assessed. Included are discussions of: current applications, present industrial production, low-cost silicon production techniques, energy payback periods for solar cells, advanced materials research and development, concentrator systems, balance-of-system components. Also discussed are some nontechnical aspects, including foreign markets, US government program approach, and industry attitudes and approaches. (LEW)

  15. Photovoltaics - The endless spring

    Science.gov (United States)

    Brandhorst, H. W., Jr.

    1984-01-01

    An overview of the developments in the photovoltaic field over the past decade or two is presened. Accomplishments in the terrestrial field are reviewed along with projections and challenges toward meeting cost goals. The contrasts and commonality of space and terrestrial photovoltaics are presented. Finally, a strategic philosophy of photovoltaics research highlighting critical factors, appropriate directions, emerging opportunities, and challenges of the future is given.

  16. Photovoltaics: The endless spring

    Science.gov (United States)

    Brandhorst, H. W., Jr.

    1984-01-01

    An overview of the developments in the photovoltaic field over the past decade or two is presented. Accomplishments in the terrestrial field are reviewed along with projections and challenges toward meeting cost goals. The contrasts and commonality of space and terrestrial photovoltaics are presented. Finally, a strategic philosophy of photovoltaics research highlighting critical factors, appropriate directions, emerging opportunities, and challenges of the future is given.

  17. Science technology of photovoltaics

    CERN Document Server

    Reddy, P Jayarama

    2010-01-01

    A comprehensive introductory text covering solar photovoltaic technologies and its increasing number of applications to generate clean energy around the globe. It treats the fundamentals of solar cells, technologies, solar modules and arrays, solar photovoltaic systems, storage batteries, power conditioning, equipment design of solar PV systems, building integrated photovoltaics, system installation, operation and maintenance, manufacturing and worldwide players and markets. Written in a clear style and with multiple illustrations, this volume is intended for students in natural sciences, engi

  18. Thin tungsten telluride layer preparation by thermal annealing

    Science.gov (United States)

    Lu, Wei; Zhang, Yudao; Zhu, Zusong; Lai, Jiawei; Zhao, Chuan; Liu, Xuefeng; Liu, Jing; Sun, Dong

    2016-10-01

    We report a simple method to prepare a thin Tungsten Telluride (WTe2) flake with accurate thickness control, which allows preparing and studying this two dimensional material conveniently. First, the WTe2 flake, which is relatively thick due to its strong interlayer van der Waals forces, is obtained by a conventional mechanical exfoliation method. Then, the exfoliated flake is annealed at 600 °C under a constant Ar protecting flow. Raman and atomic force spectroscopy characterizations demonstrate that thermal annealing can effectively thin down the WTe2 flake and retain its original lattice structure, though its surface smoothness is slightly deteriorated. Additionally, systematical study indicates that the thinning process strongly depends on the initial thickness of the WTe2 flake before annealing: the thinning rate increases from 0.12 nm min-1 to 0.36 nm min-1 as the initial thickness increases from 10 nm to 45 nm, while the roughness of the final product also increases with the increase of its initial thickness. However, the method fails when it is applied to WTe2 flakes thicker than 100 nm, resulting in uneven or burnt surface, which is possibly caused by big cavities formed by a large amount of defects gathered at the top surface.

  19. Thickness-induced structural phase transformation of layered gallium telluride.

    Science.gov (United States)

    Zhao, Q; Wang, T; Miao, Y; Ma, F; Xie, Y; Ma, X; Gu, Y; Li, J; He, J; Chen, B; Xi, S; Xu, L; Zhen, H; Yin, Z; Li, J; Ren, J; Jie, W

    2016-07-28

    The thickness-dependent electronic states and physical properties of two-dimensional materials suggest great potential applications in electronic and optoelectronic devices. However, the enhanced surface effect in ultra-thin materials might significantly influence the structural stability, as well as the device reliability. Here, we report a spontaneous phase transformation of gallium telluride (GaTe) that occurred when the bulk was exfoliated to a few layers. Transmission electron microscopy (TEM) results indicate a structural variation from a monoclinic to a hexagonal structure. Raman spectra suggest a critical thickness for the structural transformation. First-principle calculations and thermodynamic analysis show that the surface energy and the interlayer interaction compete to dominate structural stability in the thinning process. A two-stage transformation process from monoclinic (m) to tetragonal (T) and then from tetragonal to hexagonal (h) is proposed to understand the phase transformation. The results demonstrate the crucial role of interlayer interactions in the structural stability, which provides a phase engineering strategy for device applications.

  20. In-Plane Optical Anisotropy of Layered Gallium Telluride.

    Science.gov (United States)

    Huang, Shengxi; Tatsumi, Yuki; Ling, Xi; Guo, Huaihong; Wang, Ziqiang; Watson, Garrett; Puretzky, Alexander A; Geohegan, David B; Kong, Jing; Li, Ju; Yang, Teng; Saito, Riichiro; Dresselhaus, Mildred S

    2016-09-27

    Layered gallium telluride (GaTe) has attracted much attention recently, due to its extremely high photoresponsivity, short response time, and promising thermoelectric performance. Different from most commonly studied two-dimensional (2D) materials, GaTe has in-plane anisotropy and a low symmetry with the C2h(3) space group. Investigating the in-plane optical anisotropy, including the electron-photon and electron-phonon interactions of GaTe is essential in realizing its applications in optoelectronics and thermoelectrics. In this work, the anisotropic light-matter interactions in the low-symmetry material GaTe are studied using anisotropic optical extinction and Raman spectroscopies as probes. Our polarized optical extinction spectroscopy reveals the weak anisotropy in optical extinction spectra for visible light of multilayer GaTe. Polarized Raman spectroscopy proves to be sensitive to the crystalline orientation of GaTe, and shows the intricate dependences of Raman anisotropy on flake thickness, photon and phonon energies. Such intricate dependences can be explained by theoretical analyses employing first-principles calculations and group theory. These studies are a crucial step toward the applications of GaTe especially in optoelectronics and thermoelectrics, and provide a general methodology for the study of the anisotropy of light-matter interactions in 2D layered materials with in-plane anisotropy.

  1. Magnetic properties of Cr telluride-selenide alloys

    Energy Technology Data Exchange (ETDEWEB)

    Mankovsky, Sergey; Polesya, Svetlana; Ebert, Hubert [Dept. Chemie und Biochemie, Universitaet Muenchen, Butenandtstr. 5-13, D-81377 Muenchen (Germany); Huang, Zhong-Le; Bensch, Wolfgang [Institute for Anorganic Chemistry, Olshausenstr. 40, D-24098, Kiel (Germany)

    2007-07-01

    Results of a theoretical study of the magnetic properties of Cr telluride-selenide alloys having trigonal crystal structure are presented in comparison with experimental results. Both ground state and temperature-dependent magnetic properties of Cr{sub 1-{delta}}Te and Cr{sub x}(Te{sub {alpha}}Se{sub {beta}}){sub 2} (with ratio {alpha}:{beta}=7:1,6:2,5:3) have been investigated in a wide region of chromium content. For the alloys Cr{sub x}(Te{sub {alpha}}Se{sub {beta}}){sub 2} a transition to the state with antiferromagnetic order in a fully occupied sub-lattice and with no order in a partially occupied sub-lattice was obtained. For the alloys Li{sub x}Cr{sub 0.5}Ti{sub 0.75}Se{sub 2}, a non-monotonic dependence of structural and magnetic properties have been found upon increase of Li concentration x, that is in agreement with experimental results. The ground state properties have been studied on the basis of electronic structure calculations using the Korringa-Kohn-Rostoker (KKR) band structure method combined with the CPA alloy theory. Using Monte Carlo simulations we obtained the magnetic configuration at T=0 K and studied the magnetic properties at T>0 K as well. The required exchange coupling parameters were obtained from our ab-initio electronic structure calculations.

  2. Electrolytically deposited Cadmium Selenide Films for Photovoltaic Applications

    Directory of Open Access Journals (Sweden)

    Palaiologopoulou M. D.

    2012-10-01

    Full Text Available CdSe films were electrodeposited on pure nickel substrates. The nickel substrate was polished to a mirror finish by Al2O3 paste, etched in 10% HCl solution for 40 s and rinsed thoroughly by de-ionized water. The deposition bath contained solutions with excessive Cd2+ (0.2M from CdSO4 and small amounts of SeO2 (1x10-3 M. The pH of the bath was adjusted to a value of 2.2 at RT by adding 10% H2SO4. The bath was first thermostated at the required temperature, which varied from 55°C to 65°C. Plating was accomplished at deposition potential 1000 mV (vs. Hg/Hg2SO4. The films formed had a uniform thickness and it was found to be approximately 2.0 μm thick (for 20 min electrodeposition process. The produced CdSe films were characterized by X-Ray diffraction and SEM. The induced semiconductor doping effect by thermal annealing in pure dry nitrogen gas was also investigated. Gold contacts were placed on top of the CdSe films, either by evaporation, or mechanically. Depending on the deposition parameters the electrical characteristics of the Ni/CdSe/Au structures may exhibit rectification properties. The optical excitation of the structure was investigated for various CdSe thicknesses.

  3. Urban photovoltaic electricity policies

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-10-15

    This report for the International Energy Agency (IEA) made by Task 10 of the Photovoltaic Power Systems (PVPS) programme takes a look at urban photovoltaic electricity policies. The mission of the Photovoltaic Power Systems Programme is to enhance the international collaboration efforts which accelerate the development and deployment of photovoltaic solar energy as a significant and sustainable renewable energy option. The objective of Task 10 is stated as being to enhance the opportunities for wide-scale, solution-oriented application of photovoltaics in the urban environment. The goal of the study presented was to evaluate a standardised basis for urban policies regarding photovoltaic integration in a set of cities in the countries participating in the IEA's Task 10, Urban Scale PV. The investigation was focused on three topics: the present state of the policies, the prospects for future policies fostering photovoltaic deployment and the prospects for future policies to cope with large-scale photovoltaic integration. The first section analyses the state of the policies; this analysis is then confirmed in section 2, which deals with present obstacles to PV deployment and solutions to overcome them. The third section investigates future prospects for PV deployment with the question of mastering large scale integration. The report concludes that cities could formulate urban solutions by developing integrated, specific provisions for PV deployment in their urban infrastructure planning.

  4. Photovoltaics for residential applications

    Energy Technology Data Exchange (ETDEWEB)

    1984-02-01

    Information is given about the parts of a residential photovoltaic system and considerations relevant to photovoltaic power use in homes that are also tied to utility lines. In addition, factors are discussed that influence implementation, including legal and environmental factors such as solar access and building codes, insurance, utility buyback, and system longevity. (LEW)

  5. Photovoltaic System in Progress

    DEFF Research Database (Denmark)

    Shoro, Ghulam Mustafa; Hussain, Dil Muhammad Akbar; Sera, Dezso

    2013-01-01

    This paper provides a comprehensive update on photovoltaic (PV) technologies and the materials. In recent years, targeted research advancement has been made in the photovoltaic cell technologies to reduce cost and increase efficiency. Presently, several types of PV solar panels are commercially u...

  6. Characterization of Photovoltaic Generators

    Science.gov (United States)

    Boitier, V.; Cressault, Y.

    2011-01-01

    This paper discusses photovoltaic panel systems and reviews their electrical properties and use in several industrial fields. We explain how different photovoltaic panels may be characterized by undergraduate students at university using simple methods to retrieve their electrical properties (power, current and voltage) and compare these values…

  7. Telluride films and waveguides for IR integrated optics

    Energy Technology Data Exchange (ETDEWEB)

    Barthelemy, Eleonore; Vigreux, Caroline; Pradel, Annie [Institut Charles Gerhardt Montpellier, UMR CNRS 5253, Universite Montpellier II, CC1503, 34095 Montpellier Cedex 5 (France); Parent, Gilles [Laboratoire d' Energetique et de Mecanique Theorique et Appliquee, Universite de Nancy-Lorraine, BP239, 54506 Vandoeuvre Les Nancy Cedex (France); Barillot, Marc [Thales Alenia Space, 100 Bld. du midi, BP99, 06156 Cannes La Bocca Cedex (France)

    2011-09-15

    The fabrication of micro-components for far infrared applications such as spatial interferometry requires the realization of single-mode channel waveguides being able to work in the infrared region. One of the key issues in case of channel waveguides is the selection of materials for the core layer. Amorphous telluride films are particularly attractive for their transparency in a large spectral domain in the infrared region. A second key issue is the selection of an appropriate method for film deposition. Indeed, waveguides for far infrared applications are characterized by a thick core layer (10-15 {mu}m, typically). The challenge is thus to select a deposition method which ensures the deposition of thick films of optical quality. In this paper, it is shown that thermal co-evaporation meets this challenge. In particular, it allows varying the composition of the films very easily and thus adjusting their optical properties (refractive index, optical band gap). The example of thermally co-evaporated Te-Ge films is given. Films with typical thickness of 7-15 {mu}m were elaborated. Their morphological, structural, thermal and optical properties were measured. A particular attention was paid to the checking of the film homogeneity. The realized waveguiding structures and their optical testing are then described. In particular, the first transmission measurements at 10.6 {mu}m are presented. In conclusion, the feasibility of micro-components based on the stacking and etching of chalcogenide films is demonstrated, opening the door to applications related to detection in the mid- and thermal infrared spectral domains (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Post-CMOS FinFET integration of bismuth telluride and antimony telluride thin-film-based thermoelectric devices on SoI substrate

    KAUST Repository

    Aktakka, Ethem Erkan

    2013-10-01

    This letter reports, for the first time, heterogeneous integration of bismuth telluride (Bi2Te3) and antimony telluride (Sb 2Te3) thin-film-based thermoelectric ffect transistors) via a characterized TE-film coevaporationand shadow-mask patterning process using predeposition surface treatment methods for reduced TE-metal contact resistance. As a demonstration vehicle, a 2 × 2 mm2-sized integrated planar thermoelectric generator (TEG) is shown to harvest 0.7 μ W from 21-K temperature gradient. Transistor performance showed no significant change upon post-CMOS TEG integration, indicating, for the first time, the CMOS compatibility of the Bi2Te3 and Sb2Te3 thin films, which could be leveraged for realization of high-performance integrated micro-TE harvesters and coolers. © 2013 IEEE.

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

    Science.gov (United States)

    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.

  10. Performance of hybrid photovoltaic collector

    OpenAIRE

    Garbisu Eugui, Josu

    2010-01-01

    The aim of the present project is the study of the performance of a combined photovoltaic-thermal plant, called also hybrid system, located in south Italy, evaluating the efficiency of the photovoltaic and thermal systems and the advantage respect to the two single plants (photovoltaic and thermal ). This research project has two objectives fundamentals of efficiency improvement energy from solar photovoltaic panels. On one hand, increase photovoltaic efficiency, at the same time an...

  11. Organic photovoltaic films

    Directory of Open Access Journals (Sweden)

    Jenny Nelson

    2002-05-01

    The last two years have seen an unprecedented growth of interest in solar cells made from organic electronic materials. This is partly due to the rapid growth of the photovoltaic market1, which has stimulated research into longer term, more innovative photovoltaic technologies, and partly to the development of organic electronic materials for display applications. The rapid progress in optoelectronic molecular materials has introduced a range of potential new photovoltaic materials, as well as an improved understanding of the capabilities of such materials and confidence in their application2.

  12. Clean electricity from photovoltaics

    CERN Document Server

    Green, Martin A

    2015-01-01

    The second edition of Clean Electricity from Photovoltaics , first published in 2001, provides an updated account of the underlying science, technology and market prospects for photovoltaics. All areas have advanced considerably in the decade since the first edition was published, which include: multi-crystalline silicon cell efficiencies having made impressive advances, thin-film CdTe cells having established a decisive market presence, and organic photovoltaics holding out the prospect of economical large-scale power production. Contents: The Past and Present (M D Archer); Limits to Photovol

  13. Survey of photovoltaic systems

    Energy Technology Data Exchange (ETDEWEB)

    1979-08-01

    In developing this survey of photovoltaic systems, the University of Alabama in Huntsville assembled a task team to perform an extensive telephone survey of all known photovoltaic manufacturers. Three US companies accounted for 77% of the total domestic sales in 1978. They are Solarex Corporation, Solar Power Croporation, and ARCO Solar, Inc. This survey of solar photovoltaic (P/V) manufacturers and suppliers consists of three parts: a catalog of suppliers arranged alphabetically, data sheets on specific products, and typical operating, installation, or maintenance instructions and procedures. This report does not recommend or endorse any company product or information presented within as the results of this survey.

  14. Cadmium in Sweden - environmental risks

    Energy Technology Data Exchange (ETDEWEB)

    Parkman, H.; Iverfeldt, Aa. [Swedish Environmental Research Inst. (Sweden); Borg, H.; Lithner, G. [Stockholm Univ. (Sweden). Inst. for Applied Environmental Research

    1998-03-01

    This report aims at assessing possible effects of cadmium in the Swedish environment. Swedish soils and soft freshwater systems are, due to a generally poor buffering capacity, severely affected by acidification. In addition, the low salinity in the Baltic Sea imply a naturally poor organism structure, with some important organisms living close to their limit of physiological tolerance. Cadmium in soils is mobilized at low pH, and the availability and toxicity of cadmium in marine systems are enhanced at low salinity. The Swedish environment is therefore extra vulnerable to cadmium pollution. The average concentrations of cadmium in the forest mor layers, agricultural soils, and fresh-waters in Sweden are enhanced compared to `back-ground concentrations`, with a general increasing trend from the north to the south-west, indicating strong impact of atmospheric deposition of cadmium originating from the central parts of Europe. In Swedish sea water, total cadmium concentrations, and the fraction of bio-available `free` cadmium, generally increases with decreasing salinity. Decreased emissions of cadmium to the environment have led to decreasing atmospheric deposition during the last decade. The net accumulation of cadmium in the forest mor layer has stopped, and even started to decrease. In northern Sweden, this is due to the decreased deposition, but in southern Sweden the main reason is increased leakage of cadmium from the topsoil as a consequence of acidification. As a result, cadmium in the Swedish environments is undergoing an extended redistribution between different soil compartments, and from the soils to the aquatic systems. 90 refs, 23 figs, 2 tabs. With 3 page summary in Swedish

  15. Structural Engineering of Vacancy Defected Bismuth Tellurides for Thermo-electric Applications

    Science.gov (United States)

    Termentzidis, K.; Pokropivny, A.; Xiong, S.-Y.; Chumakov, Y.; Cortona, P.; Volz, S.

    2012-10-01

    Molecular Dynamics and ab-initio simulations are used to find the most stable stoichiometries of Bismuth Tellurides with vacancy defects. The interest is to decrease the thermal conductivity of these compounds a key point to achieve high figure of merits. A reduction of 70% of the thermal conductivity is observed with Te vacancies of only 5%.

  16. Structural Engineering of Vacancy Defected Bismuth Tellurides for Thermo-electric Applications

    Directory of Open Access Journals (Sweden)

    Chumakov Y.

    2012-10-01

    Full Text Available Molecular Dynamics and ab-initio simulations are used to find the most stable stoichiometries of Bismuth Tellurides with vacancy defects. The interest is to decrease the thermal conductivity of these compounds a key point to achieve high figure of merits. A reduction of 70% of the thermal conductivity is observed with Te vacancies of only 5%.

  17. Electrodeposition of bismuth telluride thermoelectric films from a nonaqueous electrolyte using ethylene glycol

    NARCIS (Netherlands)

    Nguyen, H.P.; Wu, M.; Su, J.; Vullers, R.J.M.; Vereecken, P.M.; Fransaer, J.

    2012-01-01

    Ethylene glycol was studied as an electrolyte for the electrodeposition of thermoelectric bismuth telluride films by cyclic voltammetry, rotating ring disk electrode and electrochemical quartz crystal microbalance (EQCM). The reduction of both Bi3+ and Te4+ ions proceeds in one step without the form

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

    OpenAIRE

    Rodriguez-Torres, Marcos R.; Velez, Christian; Zayas, Beatriz; Rivera, Osvaldo; Arslan, Zikri; Gonzalez-Vega, Maxine N.; Diaz-Diestra, Daysi; Beltran-Huarac, Juan; Morell, Gerardo; Primera-Pedrozo, Oliva M.

    2015-01-01

    Cadmium selenide quantum dots (CdSe QDs), inorganic semiconducting nanocrystals, are alluring increased attraction due to their highly refined chemistry, availability, and super tunable optical properties suitable for many applications in different research areas, such as photovoltaics, light-emitting devices, environmental sciences, and nanomedicine. Specifically, they are being widely used in bio-imaging in contrast to organic dyes due to their high brightness and improved photo-stability, ...

  19. CADMIUM – ENVIRONMENTAL HAZARD

    Directory of Open Access Journals (Sweden)

    Henryka Langauer-Lewowicka

    2010-06-01

    Full Text Available The paper presents some information about current status of cadmium as an environmental health problem. Agricultural uses of phosphate fertilizers, sewage sludge and industrial uses of Cd are the major source of widespread of this metal at trace levels into the general environment and human foodstuffs. It is well known that high cadmium (Cd exposure causes renal damage, anemia, enteropathy, osteoporosis, osteomalacia, whereas the dose-response relationship at low levels exposure is less established. During the last decade an increasing number of studies have found an adverse health effects due to low environmental exposure to Cd. Many authors try to determine the relationship between Cd intake and Cd toxicity indicators, especially dealing renal tubular damage. The level of b2-microglobulin in urine is regarded as the most sensitive biomarker of renal disfunction due to low environmental Cd concentrations.

  20. Photonic Design for Photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Kosten, E.; Callahan, D.; Horowitz, K.; Pala, R.; Atwater, H.

    2014-08-28

    We describe photonic design approaches for silicon photovoltaics including i) trapezoidal broadband light trapping structures ii) broadband light trapping with photonic crystal superlattices iii) III-V/Si nanowire arrays designed for broadband light trapping.

  1. Photovoltaic solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Nielson, Gregory N; Cruz-Campa, Jose Luis; Okandan, Murat; Resnick, Paul J

    2014-05-20

    A photovoltaic solar cell for generating electricity from sunlight is disclosed. The photovoltaic solar cell comprises a plurality of spaced-apart point contact junctions formed in a semiconductor body to receive the sunlight and generate the electricity therefrom, the plurality of spaced-apart point contact junctions having a first plurality of regions having a first doping type and a second plurality of regions having a second doping type. In addition, the photovoltaic solar cell comprises a first electrical contact electrically connected to each of the first plurality of regions and a second electrical contact electrically connected to each of the second plurality of regions, as well as a passivation layer covering major surfaces and sidewalls of the photovoltaic solar cell.

  2. Photovoltaic solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Nielson, Gregory N; Okandan, Murat; Cruz-Campa, Jose Luis; Resnick, Paul J

    2013-11-26

    A photovoltaic solar cell for generating electricity from sunlight is disclosed. The photovoltaic solar cell comprises a plurality of spaced-apart point contact junctions formed in a semiconductor body to receive the sunlight and generate the electicity therefrom, the plurality of spaced-apart point contact junctions having a first plurality of regions having a first doping type and a second plurality of regions having a second doping type. In addition, the photovoltaic solar cell comprises a first electrical contact electrically connected to each of the first plurality of regions and a second electrical contact electrically connected to each of the second plurality of regions, as well as a passivation layer covering major surfaces and sidewalls of the photovoltaic solar cell.

  3. Solar photovoltaic energy

    CERN Document Server

    Labouret, Anne

    2010-01-01

    Providing designers, installers and managers with the tools and methods for the effective writing of technical reports and the ability to calculate, install and maintain the necessary components of photovoltaic energy.

  4. Photovoltaic module and interlocked stack of photovoltaic modules

    Science.gov (United States)

    Wares, Brian S.

    2014-09-02

    One embodiment relates to an arrangement of photovoltaic modules configured for transportation. The arrangement includes a plurality of photovoltaic modules, each photovoltaic module including a frame. A plurality of individual male alignment features and a plurality of individual female alignment features are included on each frame. Adjacent photovoltaic modules are interlocked by multiple individual male alignment features on a first module of the adjacent photovoltaic modules fitting into and being surrounded by corresponding individual female alignment features on a second module of the adjacent photovoltaic modules. Other embodiments, features and aspects are also disclosed.

  5. Cadmium sulfite hexahydrate revisited

    Directory of Open Access Journals (Sweden)

    Sergio Baggio

    2008-07-01

    Full Text Available The present structural revision of the title compound, tetracadmium tetrasulfite hexahydrate, [Cd4(SO34(H2O5]·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 [overline{1}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.

  6. Photovoltaic systems and applications

    Energy Technology Data Exchange (ETDEWEB)

    1982-01-01

    Abstracts are given of presentations given at a project review meeting held at Albuquerque, NM. The proceedings cover the past accomplishments and current activities of the Photovoltaic Systems Research, Balance-of-System Technology Development and System Application Experiments Projects at Sandia National Laboratories. The status of intermediate system application experiments and residential system analysis is emphasized. Some discussion of the future of the Photovoltaic Program in general, and the Sandia projects in particular is also presented.

  7. Photovoltaic barometer; Barometre photovoltaique

    Energy Technology Data Exchange (ETDEWEB)

    Anon

    2009-04-15

    spain and Germany set the pace for the world photovoltaic market in 2008, which grew to more than twice its 2007 size. The European Union continued to drive photocell installation with an additional 4 592.3 MWp in 2008, or 151.6% growth over 2007. However, European growth prospects for the photovoltaic market in 2009 are being dampened by the global financial crisis and the scheduled slow-down of the Spanish market. (author)

  8. Special characteristics of fluorescence and resonance Rayleigh scattering for cadmium telluride nanocrystal aqueous solution and its interactions with aminoglycoside antibiotics

    Institute of Scientific and Technical Information of China (English)

    LI TaiShan; LIU ShaoPu; LIU ZhongFang; HU XiaoLi; ZHANG LiPing

    2009-01-01

    CdTe nanocrystals (CdTe NCs) were achieved by reaction of CdCl2 with KHTe solution and were capped with sodium mercaptoacetate. The product was detected by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive spectroscopy (EDS), fluorescence spectra, ultraviolet-visible spectra and X-ray diffraction (XRD). The CdTe NCs are of cubic structure and the average size is about 5 nm. The fluorescence quantum yield of CdTe NCs aqueous solution increased from 37% to 97% after 20 d under room light. The maximum λem of fluorescence changed from 543 nm to 510 nm and the blue shift was 33 nm. CdTe NCs aqueous solution can be steady for at least 10 months at 4℃ in a refrigerator. The resonance Rayleigh scattering (RRS) of CdTe NCs in the aqueous solution was investigated. The maximum scattering peak was located at about 554 nm. The interactions of CdTe NCs with amikacin sulfate (AS) and micronomicin sulfate (MS) were in-vestigated respectively. The effects of AS and MS on fluorescence and RRS of CdTe NCs were analyzed. It was found that AS and MS quenched the photoluminescence of CdTe NCs and enhanced RRS of CdTe NCs. Under optimum conditions, there are linear relationships between quenching intensity (F0-F), intensity of RRS (1-10) and concentration of AS and MS. The detection limits (3σ) of AS and MS are re-spectively 3.4 ng.mL-1 and 2.6 ng.mL-1 by the fluorescence quenching method, and 15.2 ng.mL-1 and 14.0 ng.mL-1 by the RRS method. The methods have high sensitivity, thus CdTe NCs may be used as fluorescence probes and RRS probes for the detection of aminoglycoside antibiotics.

  9. Crystal growth and analysis of ohmic contact and magneto-optical isolator properties of cadmium manganese telluride

    Science.gov (United States)

    Prakasam, Mythili; Viraphong, Oudomsack; Teulé-Gay, Lionel; Decourt, Rodolphe; Veber, Philippe; Víllora, Encarnación G.; Shimamura, Kiyoshi

    2011-03-01

    Cd1-xMnxTe (x=0.1, 0.3, 0.5, 0.7 and 0.9) (CMT) single crystals were grown by the vertical Bridgman method. The optical studies reveal that with the increase in Mn concentration, the band gap values increase, which is attributed to s, p-d exchange interaction between the band carriers and Mn ions. Faraday rotation angle of the grown CMT (x=0.5) crystals were measured at the following wavelengths: 825, 1060 and 1575 nm. It was inferred that CMT exhibit larger Faraday effect (3-6 times larger than terbium-gallium garnet (TGG) currently used for optical isolators) making it as an efficient material for optical isolator at longer wavelengths. Field-cooled and zero field-cooled magnetizations of CMT were measured as a function of temperature and magnetic field. The spin-glass like behavior of CMT and their tendency to decrease in magnitude with increasing Mn concentration have been analyzed. The metal contacts on the Cd1-xMnxTe (x=0.1, 0.5, 0.7 and 0.9) crystals have been made with various metals and metal alloys to establish the ohmic contact. The detector characteristics of CMT have been tested using γ-rays with 511 keV (22 Na) and 59.5 keV (241 Am).

  10. An XPS study of bromine in methanol etching and hydrogen peroxide passivation treatments for cadmium zinc telluride radiation detectors

    Science.gov (United States)

    Babar, S.; Sellin, P. J.; Watts, J. F.; Baker, M. A.

    2013-01-01

    The performance of single crystal CdZnTe radiation detectors is dependent on both the bulk and the surface properties of the material. After single crystal fabrication and mechanical polishing, modification of the surface to remove damage and reduce the surface leakage current is generally achieved through chemical etching followed by a passivation treatment. In this work, CdZnTe single crystals have been chemically etched using a bromine in methanol (BM) treatment. The BM concentrations employed were 0.2 and 2.0 (v/v) % and exposure times varied between 5 and 120 s. Angle resolved XPS and sputter depth profiling has been employed to characterize the surfaces for the different exposure conditions. A Te rich surface layer was formed for all exposures and the layer thickness was found to be independent of exposure time. The enriched Te layer thickness was accurately determined by calibrating the sputter rate against a CdTe layer of known thickness. For BM concentrations of 0.2 (v/v) % and 2 (v/v) %, the Te layer thickness was determined to be 1.3 ± 0.2 and 1.8 ± 0.2 nm, respectively. The BM etched surfaces have subsequently been passivated in a 30 wt.% H2O2 solution employing exposure time of 15 s. The oxide layer thickness has been calculated using two standard XPS methodologies, based on the Beer-Lambert expression. The TeO2 thickness calculated from ARXPS data are slightly higher than the thickness obtained by the simplified Beer-Lambert expression. For BM exposures of 30-120 s followed by a passivation treatment of 30 wt. % H2O2 solution employing an exposure time 15 s, the ARXPS method gave an average TeO2 thickness value of 1.20 nm and the simplified Beer-Lambert expression gave an average thickness value of 0.99 nm.

  11. Polycrystalline cadmium telluride n-i-p solar cell: Annual subcontract report, 1 June 1987--31 August 1988

    Energy Technology Data Exchange (ETDEWEB)

    Meyers, P.V.

    1989-06-01

    The CdS/CdTe/ZnTe n-i-p solar cell and its ternary relatives have the potential to meet Department of Energy cost, efficiency, and stability goals. This report describes results of a continuing program to achieve these goals. A record-breaking efficiency of 11% has been demonstrated and verified at the Solar Energy Research Institute (SERI). Stability testing for 3000 hours indicates that the n-i-p structure is stable. Improving the short-circuit current by substituting Cd/sub x/Zn/sub 1-x/S for CdS has been successful and has produced 8+% efficient cells with 2.6 eV windows using improved pyrolysis equipment. Transparent n-i-p devices have been produced with a SERI-verified efficiency of 9.4%. Collaborations with researchers at the Georgia Institute of Technology, the Institute of Energy Conversion, and Jet Propulsion Laboratory have resulted in jointly produced n-i-p cells. Cells produced by molecular beam epitaxy and metal organic chemical vapor deposition had efficiencies greater than 9%; cells produced by thermal vacuum evaporation had efficiencies greater than 7%. 18 refs., 35 figs., 13 tabs.

  12. Micro-Raman and UV-VIS Studies of 100 MeV Ni4+ Irradiated Cadmium Telluride Thin Films

    Directory of Open Access Journals (Sweden)

    Neelam Pahwa

    2011-01-01

    Full Text Available CdTe thin films grown by thermal evaporation on quartz substrates were irradiated with Swift (100 MeV Ni 4 + ions for fluences in the range 1.0 × 1011 - 1.0 × 1013 cm – 2. The modification in the structure and optical properties has been studied as a function of ion fluence using Micro-Raman spectroscopy and UV-VIS spectroscopy. In Micro Raman spectrum, weak LO and TO modes of CdTe and A1 & E modes of Te were observed with blue shift which was found to increase with increase in fluence. Intensity of these modes decreased with increase in ion fluence. UV-transmission showed pronounced interference fringes, indicating a good quality of the films. The bandgap was found to increase in the range 1.4-1.75 eV with increase in fluence.

  13. Gated tomographic radionuclide angiography using cadmium-zinc-telluride detector gamma camera; comparison to traditional gamma cameras

    DEFF Research Database (Denmark)

    Jensen, Maria Maj; Schmidt, Ulla; Huang, Chenxi;

    2014-01-01

    PURPOSE: Estimation of left ventricular ejection fraction (LVEF) with equilibrium 99MTc-HSA equilibrium radionuclide angiography (MUGA) is frequently used for assessing cardiac function. The purpose of this study was to compare intra- and interobserver variation between three different gamma...

  14. Special characteristics of fluorescence and resonance Rayleigh scattering for cadmium telluride nanocrystal aqueous solution and its interactions with aminoglycoside antibiotics

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    CdTe nanocrystals(CdTe NCs) were achieved by reaction of CdCl2 with KHTe solution and were capped with sodium mercaptoacetate.The product was detected by transmission electron microscopy(TEM),high-resolution transmission electron microscopy(HRTEM),energy dispersive spectroscopy(EDS),fluorescence spectra,ultraviolet-visible spectra and X-ray diffraction(XRD).The CdTe NCs are of cubic structure and the average size is about 5 nm.The fluorescence quantum yield of CdTe NCs aqueous solution increased from 37% to 97% after 20 d under room light.The maximum λem of fluorescence changed from 543 nm to 510 nm and the blue shift was 33 nm.CdTe NCs aqueous solution can be steady for at least 10 months at 4℃ in a refrigerator.The resonance Rayleigh scattering(RRS) of CdTe NCs in the aqueous solution was investigated.The maximum scattering peak was located at about 554 nm.The interactions of CdTe NCs with amikacin sulfate(AS) and micronomicin sulfate(MS) were investigated respectively.The effects of AS and MS on fluorescence and RRS of CdTe NCs were analyzed.It was found that AS and MS quenched the photoluminescence of CdTe NCs and enhanced RRS of CdTe NCs.Under optimum conditions,there are linear relationships between quenching intensity(F0-F),intensity of RRS(I-I0) and concentration of AS and MS.The detection limits(3б) of AS and MS are respectively 3.4 ng·mL-1 and 2.6 ng·mL-1 by the fluorescence quenching method,and 15.2 ng·mL-1 and 14.0 ng·mL-1 by the RRS method.The methods have high sensitivity,thus CdTe NCs may be used as fluorescence probes and RRS probes for the detection of aminoglycoside antibiotics.

  15. An Effective Approach to Improving Cadmium Telluride (111)A Surface by Molecular-Beam-Epitaxy Growth of Tellurium Monolayer.

    Science.gov (United States)

    Ren, Jie; Fu, Li; Bian, Guang; Su, Jie; Zhang, Hao; Velury, Saavanth; Yukawa, Ryu; Zhang, Longxiang; Wang, Tao; Zha, Gangqiang; Guo, Rongrong; Miller, Tom; Hasan, M Zahid; Chiang, Tai-Chang

    2016-01-13

    The surface cleansing treatment of non-natural cleavage planes of semiconductors is usually performed in vacuum using ion sputtering and subsequent annealing. In this Research Article, we report on the evolution of surface atomic structure caused by different ways of surface treatment as monitored by in situ core-level photoemission measurements of Cd-4d and Te-4d atomic levels and reflection high-energy electron diffraction (RHEED). Sputtering of surface increases the density of the dangling bonds by 50%. This feature and the less than ideal ordering can be detrimental to device applications. An effective approach is employed to improve the quality of this surface. One monolayer (ML) of Te grown by the method of molecular beam epitaxy (MBE) on the target surface with heating at 300 °C effectively improves the surface quality as evidenced by the improved sharpness of RHEED pattern and a reduced diffuse background in the spectra measured by high-resolution ultraviolet photoemission spectroscopy (HRUPS). Calculations have been performed for various atomic geometries by employing first-principles geometry optimization. In conjunction with an analysis of the core level component intensities in terms the layer-attenuation model, we propose a "vacancy site" model of the modified 1 ML-Te/CdTe(111)A (2 × 2) surface. PMID:26672795

  16. Cadmium in blood and hypertension

    Energy Technology Data Exchange (ETDEWEB)

    Eum, Ki-Do; Lee, Mi-Sun [Department of Environmental Health, Graduate School of Public Health and Institute of Health and Environment, Seoul National University, Seoul (Korea, Republic of); Paek, Domyung [Department of Environmental Health, Graduate School of Public Health and Institute of Health and Environment, Seoul National University, Seoul (Korea, Republic of)], E-mail: paekdm@snu.ac.kr

    2008-12-15

    Objectives:: This study is to examine the effect of cadmium exposure on blood pressure in Korean general population. Methods:: The study population consisted of 958 men and 944 women who participated in the 2005 Korean National Health and Nutrition Examination Survey (KNHANES), in which blood pressure and blood cadmium were measured from each participant. Results:: The mean blood cadmium level was 1.67 {mu}g/L (median level 1.55). The prevalence of hypertension was 26.2%. The blood cadmium level was significantly higher among those subjects with hypertension than those without (mean level 1.77 versus 1.64 {mu}g/dL). After adjusting for covariates, the odds ratio of hypertension comparing the highest to the lowest tertile of cadmium in blood was 1.51 (95% confidence interval 1.13 to 2.05), and a dose-response relationship was observed. Systolic, diastolic, and mean arterial blood pressure were all positively associated with blood cadmium level, and this effect of cadmium on blood pressure was markedly stronger when the kidney function was reduced. Conclusions:: Cadmium exposures at the current level may have increased the blood pressure of Korean general population.

  17. Projectbeschrijving Cadmium-informatiepunt (CIP)

    NARCIS (Netherlands)

    Meijer PJ

    1989-01-01

    To minimize the use of cadmium the Central Government has decided to perform the purchase of products and materials within the Central Government as much as possible within the Draft Cadmium Decree. The activities to achieve this are as far as could be seen at the start of the project in june 19

  18. Projectbeschrijving Cadmium-informatiepunt (CIP)

    OpenAIRE

    Meijer PJ

    1989-01-01

    To minimize the use of cadmium the Central Government has decided to perform the purchase of products and materials within the Central Government as much as possible within the Draft Cadmium Decree. The activities to achieve this are as far as could be seen at the start of the project in june 1989, mentioned in this report.

  19. 29 CFR 1926.1127 - Cadmium.

    Science.gov (United States)

    2010-07-01

    ... containment of cadmium or materials containing cadmium on the site or location at which construction...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Toxic and Hazardous Substances § 1926.1127 Cadmium. (a... forms, in all construction work where an employee may potentially be exposed to cadmium....

  20. Cadmium exposure in the Swedish environment

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    This report gives a thorough description of cadmium in the Swedish environment. It comprises three parts: Cadmium in Sweden - environmental risks;, Cadmium in goods - contribution to environmental exposure;, and Cadmium in fertilizers, soil, crops and foods - the Swedish situation. Separate abstracts have been prepared for all three parts

  1. International Photovoltaic Program Plan

    Energy Technology Data Exchange (ETDEWEB)

    Costello, D.; Koontz, R.; Posner, D.; Heiferling, P.; Carpenter, P.; Forman, S.; Perelman, L.

    1979-12-01

    The International Photovoltaics Program Plan is in direct response to the Solar Photovoltaic Energy Research, Development, and Demonstration Act of 1978 (PL 95-590). As stated in the Act, the primary objective of the plan is to accelerate the widespread use of photovoltaic systems in international markets. Benefits which could result from increased international sales by US companies include: stabilization and expansion of the US photovoltaic industry, preparing the industry for supplying future domestic needs; contribution to the economic and social advancement of developing countries; reduced world demand for oil; and improvements in the US balance of trade. The plan outlines programs for photovoltaic demonstrations, systems developments, supplier assistance, information dissemination/purchaser assistance, and an informaion clearinghouse. Each program element includes tactical objectives and summaries of approaches. A program management office will be established to coordinate and manage the program plan. Although the US Department of Energy (DOE) had the lead responsibility for preparing and implementing the plan, numerous federal organizations and agencies (US Departments of Commerce, Justice, State, Treasury; Agency for International Development; ACTION; Export/Import Bank; Federal Trade Commission; Small Business Administration) were involved in the plan's preparation and implementation.

  2. Benchmarking concentrating photovoltaic systems

    Science.gov (United States)

    Duerr, Fabian; Muthirayan, Buvaneshwari; Meuret, Youri; Thienpont, Hugo

    2010-08-01

    Integral to photovoltaics is the need to provide improved economic viability. To achieve this goal, photovoltaic technology has to be able to harness more light at less cost. A large variety of concentrating photovoltaic concepts has provided cause for pursuit. To obtain a detailed profitability analysis, a flexible evaluation is crucial for benchmarking the cost-performance of this variety of concentrating photovoltaic concepts. To save time and capital, a way to estimate the cost-performance of a complete solar energy system is to use computer aided modeling. In this work a benchmark tool is introduced based on a modular programming concept. The overall implementation is done in MATLAB whereas Advanced Systems Analysis Program (ASAP) is used for ray tracing calculations. This allows for a flexible and extendable structuring of all important modules, namely an advanced source modeling including time and local dependence, and an advanced optical system analysis of various optical designs to obtain an evaluation of the figure of merit. An important figure of merit: the energy yield for a given photovoltaic system at a geographical position over a specific period, can be calculated.

  3. Cadmium in newborns

    OpenAIRE

    Eklund, Gunilla

    2003-01-01

    Cadmium (Cd) is a well-known nephrotoxic environmental contaminant but there are indications that the developing nervous system might be even more sensitive to Cd than the kidneys in adults. Infants are exposed to Cd from various formulas and infant diets and the gastrointestinal Cd uptake is believed to be higher in newborns than in adults. Cd levels monitored in infant foods ranged between 0.74 and 27.0 µg/kg. Cow's milk formulas had the lowest levels and cereal-based formulas had up to 21 ...

  4. Photovoltaic systems in Patagonia

    Energy Technology Data Exchange (ETDEWEB)

    Lawand, T.A. [McGill Univ., Ste. Anne de Bellevue, PQ (Canada). Brace Research Inst., Macdonald Coll; Rapallini, A. [MR Consultores, Buenos Aires, (Argentina); Pedro, G. [Ente Provincial de Energia del Neuquen, Neuquen, (Argentina)

    1998-05-01

    The feasibility of using of solar photovoltaic (PV) systems in the remote cold areas of the Neuquen province in Argentina was discussed. A program was developed by the local public utility to provide schools with electricity using photovoltaic panels. The PV systems have replaced expensive diesel generators which had become unreliable. In the first phase of the program, 27 schools were electrified using photovoltaic panels, battery storage systems and simple control panels. A review of the performance of the system components under the harsh climatic conditions of the region was discussed. The program has been expanded to include about 50 family systems. Another 150 are projected for the near future. 3 refs., 2 figs., 3 tabs.

  5. Photovoltaic Subcontract Program

    Energy Technology Data Exchange (ETDEWEB)

    Surek, Thomas; Catalano, Anthony

    1993-03-01

    This report summarizes the fiscal year (FY) 1992 progress of the subcontracted photovoltaic (PV) research and development (R D) performed under the Photovoltaic Advanced Research and Development Project at the National Renewable Energy Laboratory (NREL)-formerly the Solar Energy Research Institute (SERI). The mission of the national PV program is to develop PV technology for large-scale generation of economically competitive electric power in the United States. The technical sections of the report cover the main areas of the subcontract program: the Crystalline Materials and Advanced Concepts project, the Polycrystalline Thin Films project, Amorphous Silicon Research project, the Photovoltaic Manufacturing Technology (PVMaT) project, PV Module and System Performance and Engineering project, and the PV Analysis and Applications Development project. Technical summaries of each of the subcontracted programs provide a discussion of approaches, major accomplishments in FY 1992, and future research directions.

  6. Photovoltaic programme - edition 2003

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-07-01

    This publication issued by the Swiss Federal Office of Energy's Photovoltaics (PV) Programme presents an overview (in English) of activities and projects in the photovoltaics research and pilot and demonstration area in Switzerland. Progress in the area of future solar cell technologies, modules and building integration, system technologies, planning and operating aids is summarised. Also, PV for applications in developing countries, thermo-photovoltaics and international co-operation are commented on. In the area of pilot and demonstration projects, component development, PV integration in sloping roofs, on flat roofs and noise barriers as well as further PV plant are looked at. Also, measurement campaigns, studies, statistics and further PV-related topics are summarised. This volume also presents the abstracts of reports made by the project managers of 73 research and pilot and demonstration projects in these areas for 2002.

  7. Photovoltaic barometer; Barometre photovoltaique

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2011-04-15

    The photovoltaic sector is continuing on track, just as the extent of solar energy's electricity-generating potential is dawning on the public mind. The annual global installation figure was up more than twofold in 2010 (rising from just short of 7000 MWp in 2009). It leapt to over 16000 MWp, bringing worldwide installed photovoltaic capacity close to 38000 MWp. The photovoltaic power generated in the European Union at the end of 2010 reached 22.5 TWh which means an additional capacity of 13023 MWp during 2010. Concerning the cumulated installed capacity, Germany and Spain rank first and second in the European Union with respectively 17370 MWp and 3808 MWp

  8. Cadmium immobilization by hydroxyapatite

    Directory of Open Access Journals (Sweden)

    Smičiklas Ivana D.

    2003-01-01

    Full Text Available The contamination of air, soil and water by cadmium is a great environmental problem. If cadmium occurs in nature in ionic form, soluble in water, it easily enters into the food chain. Hydroxyapatite (HAP, Ca-o(POAe(OH2 is a sparingly soluble salt and an excellent matrix for the removal of heavy metals from solutions. Considerable research attention has been paid to the bond between Cc/2+ ions and synthetic hydroxyapatite of known composition. The sorption mechanism is complex. The dominant process is ion exchange, but surface adsorption, surface complexation and coprecipitation can also contribute to the overall mechanism. The sorption capacity depends on the characteristics of hydroxyapatite itself and on the experimental conditions. Under optimum conditions a maximum capacity of 0.8 mol Cd2+/mol HAP can be achieved. HAP is a potential sorbent for the remediation of contaminated water and soil, for industrial waste treatment, and it is also referenced as a material that can be used as a barrier around waste depositories.

  9. Ab initio lattice dynamics and thermochemistry of layered bismuth telluride (Bi2Te3)

    Science.gov (United States)

    Zurhelle, Alexander F.; Deringer, Volker L.; Stoffel, Ralf P.; Dronskowski, Richard

    2016-03-01

    We present density-functional theory calculations of the lattice dynamics of bismuth telluride, yielding force constants, mean-square displacements and partial densities of phonon states which corroborate and complement previous nuclear inelastic scattering experiments. From these data, we derive an element- and energy-resolved view of the vibrational anharmonicity, quantified by the macroscopic Grüneisen parameter γ which results in 1.56. Finally, we calculate thermochemical properties in the quasiharmonic approximation, especially the heat capacity at constant pressure and the enthalpy of formation for bismuth telluride; the latter arrives at ▵H f (Bi2Te3)  =  -102 kJ mol-1 at 298 K.

  10. Synthesis of copper telluride nanowires using template-based electrodeposition method as chemical sensor

    Indian Academy of Sciences (India)

    Sandeep Arya; Saleem Khan; Suresh Kumar; Rajnikant Verma; Parveen Lehana

    2013-08-01

    Copper telluride (CuTe) nanowires were synthesized electrochemically from aqueous acidic solution of copper (II) sulphate (CuSO4.5H2O) and tellurium oxide (TeO2) on a copper substrate by template-assisted electrodeposition method. The electrodeposition was conducted at 30 °C and the length of nanowires was controlled by adjusting deposition time. Structural characteristics were examined using X-ray diffraction and scanning electron microscope which confirm the formation of CuTe nanowires. Investigation for chemical sensing was carried out using air and chloroform, acetone, ethanol, glycerol, distilled water as liquids having dielectric constants 1, 4.81, 8.93, 21, 24.55, 42.5 and 80.1, respectively. The results unequivocally prove that copper telluride nanowires can be fabricated as chemical sensors with enhanced sensitivity and reliability.

  11. Kelvin probe studies of cesium telluride photocathode for the AWA photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    Velazquez, D.; Wisniewski, E. E.; Yusof, Z.; Harkay, K.; Spentzouris, L.; Terry, J. [Physics Department at Illinois Institute of Technology, Chicago, IL 60616 and High Energy Physics Division at Argonne National Laboratory, Lemont, IL 60439 (United States); High Energy Physics Division at Argonne National Laboratory, Lemont, IL 60439 (United States); Accelerator Science Division at Argonne National Laboratory, Lemont, IL 60439 (United States); Physics Department at Illinois Institute of Technology, Chicago, IL 60616 (United States)

    2012-12-21

    Cesium telluride is an important photocathode as an electron source for particle accelerators. It has a relatively high quantum efficiency (> 1%), is robust in a photoinjector, and long lifetime. This photocathode is fabricated in-house for a new Argonne Wakefield Accelerator (AWA) beamline to produce high charge per bunch ({approx}50 nC) in a long bunch train. We present some results from a study of the work function of cesium telluride photocathode using the Kelvin Probe technique. The study includes an investigation of the correlation between the quantum efficiency and the work function, the effect of photocathode aging, the effect of UV light exposure on the work function, and the evolution of the work function during and after photocathode rejuvenation via heating.

  12. Concentrating photovoltaic solar panel

    Science.gov (United States)

    Cashion, Steven A; Bowser, Michael R; Farrelly, Mark B; Hines, Braden E; Holmes, Howard C; Johnson, Jr., Richard L; Russell, Richard J; Turk, Michael F

    2014-04-15

    The present invention relates to photovoltaic power systems, photovoltaic concentrator modules, and related methods. In particular, the present invention features concentrator modules having interior points of attachment for an articulating mechanism and/or an articulating mechanism that has a unique arrangement of chassis members so as to isolate bending, etc. from being transferred among the chassis members. The present invention also features adjustable solar panel mounting features and/or mounting features with two or more degrees of freedom. The present invention also features a mechanical fastener for secondary optics in a concentrator module.

  13. Asphaltene based photovoltaic devices

    Science.gov (United States)

    Chianelli, Russell R.; Castillo, Karina; Gupta, Vipin; Qudah, Ali M.; Torres, Brenda; Abujnah, Rajib E.

    2016-03-22

    Photovoltaic devices and methods of making the same, are disclosed herein. The cell comprises a photovoltaic device that comprises a first electrically conductive layer comprising a photo-sensitized electrode; at least one photoelectrochemical layer comprising metal-oxide particles, an electrolyte solution comprising at least one asphaltene fraction, wherein the metal-oxide particles are optionally dispersed in a surfactant; and a second electrically conductive layer comprising a counter-electrode, wherein the second electrically conductive layer comprises one or more conductive elements comprising carbon, graphite, soot, carbon allotropes or any combinations thereof.

  14. Three-dimensional photovoltaics

    Science.gov (United States)

    Myers, Bryan; Bernardi, Marco; Grossman, Jeffrey C.

    2010-03-01

    The concept of three-dimensional (3D) photovoltaics is explored computationally using a genetic algorithm to optimize the energy production in a day for arbitrarily shaped 3D solar cells confined to a given area footprint and total volume. Our simulations demonstrate that the performance of 3D photovoltaic structures scales linearly with height, leading to volumetric energy conversion, and provides power fairly evenly throughout the day. Furthermore, we show that optimal 3D shapes are not simple box-like shapes, and that design attributes such as reflectivity can be optimized in new ways using three-dimensionality.

  15. The DOE photovoltaics program

    Science.gov (United States)

    Ferber, R. R.

    1983-01-01

    The considered program of the U.S. Department of Energy (DOE) has the objective to provide federal support for research and development work related to photovoltaics. According to definitions of policy in 1981, a strong emphasis is to be placed on long-term, high-risk research and development that industry could not reasonably be expected to perform using their own funds. Attention is given to the program structure, the photovoltaics program management organization, the advanced research and development subprogram, the collector research and development subprogram, flat-plate collectors, concentrator collectors, and the systems research and technology subprogram.

  16. Distributed photovoltaic grid transformers

    CERN Document Server

    Shertukde, Hemchandra Madhusudan

    2014-01-01

    The demand for alternative energy sources fuels the need for electric power and controls engineers to possess a practical understanding of transformers suitable for solar energy. Meeting that need, Distributed Photovoltaic Grid Transformers begins by explaining the basic theory behind transformers in the solar power arena, and then progresses to describe the development, manufacture, and sale of distributed photovoltaic (PV) grid transformers, which help boost the electric DC voltage (generally at 30 volts) harnessed by a PV panel to a higher level (generally at 115 volts or higher) once it is

  17. Photovoltaic array performance model.

    Energy Technology Data Exchange (ETDEWEB)

    Kratochvil, Jay A.; Boyson, William Earl; King, David L.

    2004-08-01

    This document summarizes the equations and applications associated with the photovoltaic array performance model developed at Sandia National Laboratories over the last twelve years. Electrical, thermal, and optical characteristics for photovoltaic modules are included in the model, and the model is designed to use hourly solar resource and meteorological data. The versatility and accuracy of the model has been validated for flat-plate modules (all technologies) and for concentrator modules, as well as for large arrays of modules. Applications include system design and sizing, 'translation' of field performance measurements to standard reporting conditions, system performance optimization, and real-time comparison of measured versus expected system performance.

  18. Aqueous-solution route to zinc telluride films for application to CO₂ reduction.

    Science.gov (United States)

    Jang, Ji-Wook; Cho, Seungho; Magesh, Ganesan; Jang, Youn Jeong; Kim, Jae Young; Kim, Won Yong; Seo, Jeong Kon; Kim, Sungjee; Lee, Kun-Hong; Lee, Jae Sung

    2014-06-01

    As a photocathode for CO2 reduction, zinc-blende zinc telluride (ZnTe) was directly formed on a Zn/ZnO nanowire substrate by a simple dissolution-recrystallization mechanism without any surfactant. With the most negative conduction-band edge among p-type semiconductors, this new photocatalyst showed efficient and stable CO formation in photoelectrochemical CO2 reduction at -0.2--0.7 V versus RHE without a sacrificial reagent.

  19. The first trialkylphosphane telluride complexes of Ag(I): molecular, ionic and supramolecular structural alternatives.

    Science.gov (United States)

    Daniliuc, Constantin; Druckenbrodt, Christian; Hrib, Cristian G; Ruthe, Frank; Blaschette, Armand; Jones, Peter G; du Mont, Wolf-W

    2007-05-28

    The structures of the first phosphane telluride complexes of silver(I), obtained from i-Pr3PTe (1) with AgNMs2 [Ms = SO2CH3] and with AgSbF6, reveal the superior coordinating ability of 1, particularly as a bridging ligand, compared with related i-Pr3PS and i-Pr3PSe ligands. PMID:17713078

  20. Road map for photovoltaic electricity

    International Nuclear Information System (INIS)

    This road map aims at highlighting industrial, technological and social challenges, at elaborating comprehensive visions, at highlighting technological locks, and at outlining research needs for the photovoltaic sector. It considers the following sector components: preparation of photo-sensitive materials, manufacturing of photovoltaic cells, manufacturing of photovoltaic arrays, design and manufacturing of electric equipment to control photovoltaic arrays and to connect them to the grid. It highlights the demand for photovoltaic installations, analyzes the value chain, proposes a vision of the sector by 2050 and defines target for 2020, discusses needs for demonstration and experimentation

  1. Photovoltaic mounting/demounting unit

    DEFF Research Database (Denmark)

    2014-01-01

    which when the mounting/demounting unit is moved along the mounting surface, causes the photovoltaic module to be mounted or demounted to the support structure; wherein the photovoltaic module comprises a carrier foil and wherein a total thickness of the photo voltaic module is below 500 muiotaeta......The present invention relates to a photovoltaic arrangement comprising a photovoltaic assembly comprising a support structure defining a mounting surface onto which a photovoltaic module is detachably mounted; and a mounting/demounting unit comprising at least one mounting/demounting apparatus...

  2. Photovoltaics fundamentals, technology and practice

    CERN Document Server

    Mertens, Konrad

    2013-01-01

    Concise introduction to the basic principles of solar energy, photovoltaic systems, photovoltaic cells, photovoltaic measurement techniques, and grid connected systems, overviewing the potential of photovoltaic electricity for students and engineers new to the topic After a brief introduction to the topic of photovoltaics' history and the most important facts, Chapter 1 presents the subject of radiation, covering properties of solar radiation, radiation offer, and world energy consumption. Chapter 2 looks at the fundamentals of semiconductor physics. It discusses the build-up of semiconducto

  3. Modelling the Photovoltaic Module

    DEFF Research Database (Denmark)

    Katsanevakis, Markos

    2011-01-01

    This paper refers into various ways in simulation the Photovoltaic (PV) module behaviour under any combination of solar irradiation and ambient temperature. There are three different approaches presented here briefly and one of them is chosen because of its good accuracy and relatively low...

  4. Printed paper photovoltaic cells

    Energy Technology Data Exchange (ETDEWEB)

    Huebler, Arved; Trnovec, Bystrik; Zillger, Tino; Ali, Moazzam; Wetzold, Nora [Inistitute for Print and Media Technology, Chemnitz University of Technology, Chemnitz (Germany); Mingebach, Markus; Wagenpfahl, Alexander; Deibel, Carsten [Experimental Physics VI, Julius-Maximilians-University of Wuerzburg (Germany); Dyakonov, Vladimir [Experimental Physics VI, Julius-Maximilians-University of Wuerzburg (Germany); Bavarian Center for Applied Energy Research e.V. (ZAE Bayern), Wuerzburg (Germany)

    2011-11-15

    Polymer/fullerene solar cells are printed on paper using a combination of gravure and flexographic printing techniques. The printed paper photovoltaic cells are free from expensive electrodes made with indium-tin oxide, silver, or gold. Oxidized zinc film is used as the electron-collecting layer. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. BMDO photovoltaics program overview

    Science.gov (United States)

    Caveny, Leonard H.; Allen, Douglas M.

    1994-01-01

    This is an overview of the Ballistic Missile Defense Organization (BMDO) Photovoltaic Program. Areas discussed are: (1) BMDO advanced Solar Array program; (2) Brilliant Eyes type satellites; (3) Electric propulsion; (4) Contractor Solar arrays; (5) Iofee Concentrator and Cell development; (6) Entech linear mini-dome concentrator; and (7) Flight test update/plans.

  6. Photovoltaics in Japan

    Science.gov (United States)

    Shimada, K.

    1985-01-01

    Report surveys status of research and development on photovoltaics in Japan. Report based on literature searches, private communications, and visits by author to Japanese facilities. Included in survey are Sunshine Project, national program to develop energy sources; industrial development at private firms; and work at academic institutions.

  7. Photovoltaic solar; Solaire photovoltaique

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-01-01

    This study aims to observe, from european examples, the local governments policies in matter of the photovoltaic development. This approach is very different for each town. The first part evaluates the initiatives, the second part is devoted to the global situation in Europe and the third part brings recommendations. (A.L.B.)

  8. Air Stable Photovoltaic Device

    DEFF Research Database (Denmark)

    2010-01-01

    A method of forming a conducting polymer based photovoltaic device comprising the steps of : (a) providing a transparent first electrode; (b) providing the transparent first electrode with a layer of metal oxide nanoparticles, wherein the metal oxide is selected from the group consisting of : TiO...

  9. Photovoltaics (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    DOE Solar Energy Technologies Program

    2011-10-13

    DOE works with national labs, academia, and industry to support the domestic photovoltaics (PV) industry and research enterprise. SunShot aims to achieve widespread, unsubsidized cost-competitiveness through an applied research and development (R&D) portfolio spanning PV materials, devices, and manufacturing technologies.

  10. Cadmium(2) complexes of cytosine

    International Nuclear Information System (INIS)

    Complexes of cadmium(2) with cytosine obtained from aqueous or physiological solutions at room temperature are reported. The complexes were characterized by spectroscopic, conductometric, 1H-NMR, and 13C-NMR measurements and also by thermogravimetry. (Authors)

  11. Discovery of the Cadmium Isotopes

    OpenAIRE

    Amos, S.; Thoennessen, M

    2009-01-01

    Thirty-seven cadmium isotopes have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

  12. Photovoltaic Specialists Conference, 15th, Kissimmee, FL, May 12-15, 1981, Conference Record

    Science.gov (United States)

    GaAs cells for space applications are considered, taking into account AlGaAs/GaAs high efficiency cascade solar cells, and a thermochemical model of radiation damage and continuous annealing applied to GaAs solar cells. Other topics discussed are related to silicon solar cells for space applications, photovoltaic concentrator receivers and application experiments, photovoltaic concentrator cells, economics and feasibility analysis, space solar cell calibration, low cost technology for space applications, thin film solar cells, low cost processes, and low cost cell and array processes. A description is also presented of subjects in the areas of low cost Si and sheet technology, amorphous silicon solar cells, flat-plate array subsystem and system technology, cadmium sulfide and copper sulfide solar cells, flat-plate array subsystem design and test methods, module failure/degradation mechanism and reliability, measurement techniques for photovoltaic cells and materials, and flat-plate residential and intermediate system applications.

  13. Speciation of Dissolved Cadmium

    DEFF Research Database (Denmark)

    Holm, Peter Engelund; Andersen, Sjur; Christensen, Thomas Højlund

    1995-01-01

    ) method separates dissolved Cd into free divalent Cd (Cd 2+) and complexed Cd and furthermore separates the latter into the operationally defined forms: labile, slowly labile and stable complexes. The dialysis (ED) method determines high molecular weight Cd complexes (above 1000mol. wt). For both methods...... the reproducibility was good. By combining the results of the GEOCHEM calculations in terms of the inorganic complexes, and the IE results, the fractions of free and inorganically complexed Cd were estimated. The IE and ED results furthermore provided information about the organic complexes. Selected environmental......Equilibrium dialysis and ion exchange methods, as well as computer calculations (GEOCHEM), were applied for speciation of dissolved cadmium (Cd) in test solutions and leachate samples. The leachate samples originated from soil, compost, landfill waste and industrial waste. The ion exchange (IE...

  14. General Situations of Development of Photovoltaic Agriculture

    Institute of Scientific and Technical Information of China (English)

    Xiaohang; ZHANG; Shoufu; CUI; Fuping; LIU

    2015-01-01

    This paper firstly introduced policy of photovoltaic agriculture in China. It discussed significance of developing photovoltaic agriculture. Then,it introduced progress in application of photovoltaic agriculture at both home and abroad. Finally,it pointed out existing problems in photovoltaic agriculture and came up with recommendations for development of photovoltaic agriculture in China.

  15. Photovoltaic module and interlocked stack of photovoltaic modules

    Science.gov (United States)

    Wares, Brian S.

    2012-09-04

    One embodiment relates to an arrangement of photovoltaic modules configured for transportation. The arrangement includes a plurality of photovoltaic modules, each photovoltaic module including a frame having at least a top member and a bottom member. A plurality of alignment features are included on the top member of each frame, and a plurality of alignment features are included on the bottom member of each frame. Adjacent photovoltaic modules are interlocked by the alignment features on the top member of a lower module fitting together with the alignment features on the bottom member of an upper module. Other embodiments, features and aspects are also disclosed.

  16. Three-phase Photovoltaic Systems

    DEFF Research Database (Denmark)

    Kerekes, Tamas; Sera, Dezso; Máthé, Lászlo

    2015-01-01

    the grid through a three-phase power electronic converter are now well on the way to becoming a major player in the power system in many countries. Therefore, this article gives an overview of photovoltaic systems with a focus on three-phase applications, presenting these both from a hardware point of view......Photovoltaic technology has experienced unprecedented growth in the last two decades, transforming from mainly off-grid niche generation to a major renewable energy technology, reaching approximately 180 GW of capacity worldwide at the end of 2014. Large photovoltaic power plants interfacing......, detailing the different photovoltaic inverter structures and topologies as well as discussing the different control layers within a grid-connected photovoltaic plant. Modulation schemes for various photovoltaic inverter topologies, grid synchronization, current control, active and reactive power control...

  17. Zinc-induced protection against cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Early, J.L.; Schnell, R.C.

    1978-02-01

    Pretreatment of male rats with cadmium acetate potentiates the duration of hexobarbital hypnosis and inhibits the rate of hepatic microsomal drug metabolism. Pretreatment of rats with zinc acetate protects against these alterations in drug action elicited by cadmium.

  18. Inverted organic photovoltaic cells.

    Science.gov (United States)

    Wang, Kai; Liu, Chang; Meng, Tianyu; Yi, Chao; Gong, Xiong

    2016-05-21

    The advance in lifestyle, modern industrialization and future technological revolution are always at high expense of energy consumption. Unfortunately, there exist serious issues such as limited storage, high cost and toxic contamination in conventional fossil fuel energy sources. Instead, solar energy represents a renewable, economic and green alternative in the future energy market. Among the photovoltaic technologies, organic photovoltaics (OPVs) demonstrate a cheap, flexible, clean and easy-processing way to convert solar energy into electricity. However, OPVs with a conventional device structure are still far away from industrialization mainly because of their short lifetime and the energy-intensive deposition of top metal electrode. To address the stability and cost issue simultaneously, an inverted device structure has been introduced into OPVs, bridging laboratory research with practical application. In this review, recent progress in device structures, working mechanisms, functions and advances of each component layer as well their correlations with the efficiency and stability of inverted OPVs are reviewed and illustrated.

  19. Superstructure high efficiency photovoltaics

    Science.gov (United States)

    Wagner, M.; So, L. C.; Leburton, J. P.

    1987-01-01

    A novel class of photovoltaic cascade structures is introduced which features multijunction upper subcells. These superstructure high efficiency photovoltaics (SHEP's) exhibit enhanced upper subcell spectral response because of the additional junctions which serve to reduce bulk recombination losses by decreasing the mean collection distance for photogenerated minority carriers. Two possible electrical configurations were studied and compared: a three-terminal scheme that allows both subcells to be operated at their individual maximum power points and a two-terminal configuration with an intercell ohmic contact for series interconnection. The three-terminal devices were found to be superior both in terms of beginning-of-life expectancy and radiation tolerance. Realistic simulations of three-terminal AlGaAs/GaAs SHEP's show that one sun AMO efficiencies in excess of 26 percent are possible.

  20. Photovoltaic Solar Energy Generation

    CERN Document Server

    Lotsch, H.K.V; U.Hoffmann, Volker; Rhodes, William T; Asakura, Toshimitsu; Brenner, Karl-Heinz; Hänsch, Theodor W; Kamiya, Takeshi; Krausz, Ferenc; Monemar, Bo; Venghaus, Herbert; Weber, Horst; Weinfurter, Harald

    2005-01-01

    This comprehensive description and discussion of photovoltaics (PV) is presented at a level that makes it accessible to the interested academic. Starting with an historical overview, the text outlines the relevance of photovoltaics today and in the future. Then follows an introduction to the physical background of solar cells and the most important materials and technologies, with particular emphasis placed on future developments and prospects. The book goes beyond technology by also describing the path from the cell to the module to the system, proceeding to important applications, such as grid-connected and stand-alone systems. The composition and development of the markets and the role of PV in future energy systems are also considered. Finally, the discussion turns to the future structure of energy supplies, expected to comprise more distributed generation, and addresses synergies and competition from other carbon-free energy sources.

  1. Inverted organic photovoltaic cells.

    Science.gov (United States)

    Wang, Kai; Liu, Chang; Meng, Tianyu; Yi, Chao; Gong, Xiong

    2016-05-21

    The advance in lifestyle, modern industrialization and future technological revolution are always at high expense of energy consumption. Unfortunately, there exist serious issues such as limited storage, high cost and toxic contamination in conventional fossil fuel energy sources. Instead, solar energy represents a renewable, economic and green alternative in the future energy market. Among the photovoltaic technologies, organic photovoltaics (OPVs) demonstrate a cheap, flexible, clean and easy-processing way to convert solar energy into electricity. However, OPVs with a conventional device structure are still far away from industrialization mainly because of their short lifetime and the energy-intensive deposition of top metal electrode. To address the stability and cost issue simultaneously, an inverted device structure has been introduced into OPVs, bridging laboratory research with practical application. In this review, recent progress in device structures, working mechanisms, functions and advances of each component layer as well their correlations with the efficiency and stability of inverted OPVs are reviewed and illustrated. PMID:27087582

  2. Photovoltaic prospects in Europe

    Science.gov (United States)

    Starr, M. R.

    The economics of solar cells is reviewed with an eye to potential cost reductions in processing, and potential markets are explored. Current solar cell systems costs are noted to be on the road to achieving the U.S. DoE goals of $0.40/kWp by 1990. Continued progress will depend on technical developments in cheaper materials and processes, scaling up production, and the success of sales programs. Various consumer and professional markets are outlined, with a prediction that a 12 MWp deman will be reached as a steady state by 1995. Photovoltaic panels may conceivably replace conventional roofing materials, resulting in the projection that, if grid-supplied power continues to inflate in price, then all new European homes would be equipped with photovoltaics by the year 2000. Further, accomplishment of the cost goals could generate a 1 GWp/yr industrial market at the same time.

  3. Photovoltaic solar energy conversion

    CERN Document Server

    Bauer, Gottfried H

    2015-01-01

    This concise primer on photovoltaic solar energy conversion invites readers to reflect on the conversion of solar light into energy at the most fundamental level and encourages newcomers to the field to help find meaningful answers on how photovoltaic solar energy conversion can work (better), eventually contributing to its ongoing advancement. The book is based on lectures given to graduate students in the Physics Department at the University of Oldenburg over the last two decades, yet also provides an easy-to-follow introduction for doctoral and postdoctoral students from related disciplines such as the materials sciences and electrical engineering. Inspired by classic textbooks in the field, it reflects the author’s own ideas on how to understand, visualize and eventually teach the microscopic physical mechanisms and effects, while keeping the text as concise as possible so as to introduce interested readers to the field and balancing essential knowledge with open questions.

  4. Mead photovoltaic system controller

    Energy Technology Data Exchange (ETDEWEB)

    Millner, A.R.

    1979-01-31

    A system controller has been designed, built, tested, and in operation for one year at MIT/Lincoln Laboratory's 25-kW-peak Solar Photovoltaic Power System located at Mead, Nebraska. The controller allows the site to operate without human intervention, and has brought to light some of the problems of charge-control algorithms in a deep-discharge environment.

  5. Photovoltaic systems. Program summary

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-12-01

    Each of the Department of Energy's Photovoltaic Systems Program projects funded and/or in existence during fiscal year 1978 (October 1, 1977 through September 30, 1978) are described. The project sheets list the contractor, principal investigator, and contract number and funding and summarize the programs and status. The program is divided into various elements: program assessment and integration, research and advanced development, technology development, system definition and development, system application experiments, and standards and performance criteria. (WHK)

  6. Photonics in photovoltaic systems

    OpenAIRE

    Gambert, Andreas; Luque López, Antonio

    2008-01-01

    This paper gives an overview on photonics for photovoltaic systems. Starting from the spectral and angular distribution of the electromagnetic radiation from the sun, many important optical approaches how to improve the efficiency of solar cells are presented and discussed. Topics include antireflective coatings, various light trapping structures, refractive, reflective and fluorescent concentrators, and components for spectral management. The theoretical background is shortly described and e...

  7. Advances in photovoltaic technology

    Science.gov (United States)

    Landis, G. A.; Bailey, S. G.

    1992-01-01

    The advances in solar cell efficiency, radiation tolerance, and cost in the last 10 years are presented. The potential performance of thin-film solar cells in space is examined, and the cost and the historical trends in production capability of the photovoltaics industry are considered with respect to the needs of satellite solar power systems. Attention is given to single-crystal cells, concentrator and cascade cells, and thin-film solar cells.

  8. Increased voltage photovoltaic cell

    Science.gov (United States)

    Ross, B.; Bickler, D. B.; Gallagher, B. D. (Inventor)

    1985-01-01

    A photovoltaic cell, such as a solar cell, is provided which has a higher output voltage than prior cells. The improved cell includes a substrate of doped silicon, a first layer of silicon disposed on the substrate and having opposite doping, and a second layer of silicon carbide disposed on the first layer. The silicon carbide preferably has the same type of doping as the first layer.

  9. Photovoltaic cell array

    Science.gov (United States)

    Eliason, J. T. (Inventor)

    1976-01-01

    A photovoltaic cell array consisting of parallel columns of silicon filaments is described. Each fiber is doped to produce an inner region of one polarity type and an outer region of an opposite polarity type to thereby form a continuous radial semi conductor junction. Spaced rows of electrical contacts alternately connect to the inner and outer regions to provide a plurality of electrical outputs which may be combined in parallel or in series.

  10. Analysis methods for photovoltaic applications

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-01-01

    Because photovoltaic power systems are being considered for an ever-widening range of applications, it is appropriate for system designers to have knowledge of and access to photovoltaic power systems simulation models and design tools. This brochure gives brief descriptions of a variety of such aids and was compiled after surveying both manufacturers and researchers. Services available through photovoltaic module manufacturers are outlined, and computer codes for systems analysis are briefly described. (WHK)

  11. Recent developments in photovoltaics

    International Nuclear Information System (INIS)

    The photovoltaic market is booming with over 30% per annum compounded growth over the last five years. The government-subsidised urban-residential use of photovoltaics, particularly in Germany and Japan, is driving this sustained growth. Most of the solar cells being supplied to this market are 'first generation' devices based on crystalline or multi-crystalline silicon wafers. 'Second generation' thin-film solar cells based on amorphous silicon/hydrogen alloys or polycrystalline compound semiconductors are starting to appear on the market in increasing volume. Australian contributions in this area are the thin-film polycrystalline silicon-on-glass technology developed by Pacific Solar and the dye sensitised nanocrystalline titanium cells developed by Sustainable Technologies International. In these thin-film approaches, the major material cost component is usually the glass sheet onto which the film is deposited. After reviewing the present state of development of both cell and application technologies, the likely future development of photovoltaics is outlined. (author)

  12. Photocurrent of Photovoltaic Cells

    Science.gov (United States)

    Peeler, Seth; McIntyre, Max; Cossel, Raquel; Bowser, Chris; Tzolov, Marian

    Photovoltaic cells can be used to harness clean, renewable energy from light. Examined in this project were photovoltaic cells based on a bulk heterojunction between PCPDTBT and PCBM sandwiched between an ITO anode and an Al cathode. Current-voltage characteristics and impedance spectra for multiple photovoltaic devices were taken under varying DC electrical bias and different level of illumination. This data was interpreted in terms of an equivalent circuit with linear elements, e.g. capacitance, series resistance, and parallel resistance. A physical interpretation of each circuit element will be presented. The spectral response of the devices was characterized by optical transmission and photocurrent spectroscopy using a spectrometer in the spectral range from 300 to 900 nm. The DC measurements confirmed that the devices are electrically rectifying. The AC measurements allowed modeling of the devices as a dielectric between two electrodes with injection current passing through it. The characteristic peaks for both PCBDTBT and PCBM are clearly visible in both the photocurrent and transmission data. The good correlation between the photocurrent and transmission data indicates photocurrent generation due to absorption in both materials constituting the heterojunction.

  13. Photovoltaic self-assembly.

    Energy Technology Data Exchange (ETDEWEB)

    Lavin, Judith; Kemp, Richard Alan; Stewart, Constantine A.

    2010-10-01

    This late-start LDRD was focused on the application of chemical principles of self-assembly on the ordering and placement of photovoltaic cells in a module. The drive for this chemical-based self-assembly stems from the escalating prices in the 'pick-and-place' technology currently used in the MEMS industries as the size of chips decreases. The chemical self-assembly principles are well-known on a molecular scale in other material science systems but to date had not been applied to the assembly of cells in a photovoltaic array or module. We explored several types of chemical-based self-assembly techniques, including gold-thiol interactions, liquid polymer binding, and hydrophobic-hydrophilic interactions designed to array both Si and GaAs PV chips onto a substrate. Additional research was focused on the modification of PV cells in an effort to gain control over the facial directionality of the cells in a solvent-based environment. Despite being a small footprint research project worked on for only a short time, the technical results and scientific accomplishments were significant and could prove to be enabling technology in the disruptive advancement of the microelectronic photovoltaics industry.

  14. Photovoltaic module reliability workshop

    Energy Technology Data Exchange (ETDEWEB)

    Mrig, L. (ed.)

    1990-01-01

    The paper and presentations compiled in this volume form the Proceedings of the fourth in a series of Workshops sponsored by Solar Energy Research Institute (SERI/DOE) under the general theme of photovoltaic module reliability during the period 1986--1990. The reliability Photo Voltaic (PV) modules/systems is exceedingly important along with the initial cost and efficiency of modules if the PV technology has to make a major impact in the power generation market, and for it to compete with the conventional electricity producing technologies. The reliability of photovoltaic modules has progressed significantly in the last few years as evidenced by warranties available on commercial modules of as long as 12 years. However, there is still need for substantial research and testing required to improve module field reliability to levels of 30 years or more. Several small groups of researchers are involved in this research, development, and monitoring activity around the world. In the US, PV manufacturers, DOE laboratories, electric utilities and others are engaged in the photovoltaic reliability research and testing. This group of researchers and others interested in this field were brought together under SERI/DOE sponsorship to exchange the technical knowledge and field experience as related to current information in this important field. The papers presented here reflect this effort.

  15. Quo Vadis photovoltaics 2011

    Directory of Open Access Journals (Sweden)

    Jäger-Waldau A.

    2011-09-01

    Full Text Available Since more than 10 years photovoltaics is one of the most dynamic industries with growth rates well beyond 40% per annum. This growth is driven not only by the progress in materials knowledge and processing technology, but also by market introduction programmes in many countries around the world. Despite the negative impacts on the economy by the financial crisis since 2009, photovoltaics is still growing at an extraordinary pace and had in 2010 an extraordinary success, as both production and markets doubled. The open question is what will happen in 2011 and the years after as the situation is dominated by huge manufacturing overcapacities and an increasing unpredictability of policy support. How can the PV industry continue their cost reduction to ensure another 10 to 20 years of sustained and strong growth necessary to make PV to one of the main pillars of a sustainable energy supply in 2030. Despite the fact, that globally the share of electricity from photovoltaic systems is still small, at local level it can be already now above 30% of the demand at certain times of the year. Future research in PV has to provide intelligent solutions not only on the solar cell alone, but also on the module and the system integration level in order to permit a 5 to 10% share of electricity in 2020.

  16. Quantum Dot Based Photovoltaics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Hybrid photovoltaic cells that combine nanostructured inorganic semiconductors with organic conductors such as the cell proposed, show promise for energy generation...

  17. Solar photovoltaics for development applications

    Energy Technology Data Exchange (ETDEWEB)

    Shepperd, L.W. [Florida Solar Energy Center, Cape Canaveral, FL (United States); Richards, E.H. [Sandia National Labs., Albuquerque, NM (United States)

    1993-08-01

    This document introduces photovoltaic technology to individuals and groups specializing in development activities. Examples of actual installations illustrate the many services supplied by photovoltaic systems in development applications, including water pumping, lighting, health care, refrigeration, communications, and a variety of productive uses. The various aspects of the technology are explored to help potential users evaluate whether photovoltaics can assist them in achieving their organizational goals. Basic system design, financing techniques, and the importance of infrastructure are included, along with additional sources of information and major US photovoltaic system suppliers.

  18. Do photovoltaics have a future

    Science.gov (United States)

    Williams, B. F.

    1979-01-01

    There is major concern as to the economic practicality of widespread terrestrial use because of the high cost of the photovoltaic arrays themselves. Based on their high efficiency, photovoltaic collectors should be one of the cheapest forms of energy generators known. Present photovoltaic panels are violating the trend of lower costs with increasing efficiency due to their reliance on expensive materials. A medium technology solution should provide electricity competitive with the existing medium to high technology energy generators such as oil, coal, gas, and nuclear fission thermal plants. Programs to reduce the cost of silicon and develop reliable thin film materials have a realistic chance of producing cost effective photovoltaic panels.

  19. Formation of Semimetallic Cobalt Telluride Nanotube Film via Anion Exchange Tellurization Strategy in Aqueous Solution for Electrocatalytic Applications.

    Science.gov (United States)

    Patil, Supriya A; Kim, Eun-Kyung; Shrestha, Nabeen K; Chang, Jinho; Lee, Joong Kee; Han, Sung-Hwan

    2015-11-25

    Metal telluride nanostructures have demonstrated several potential applications particularly in harvesting and storing green energy. Metal tellurides are synthesized by tellurization process performed basically at high temperature in reducing gas atmosphere, which makes the process expensive and complicated. The development of a facile and economical process for desirable metal telluride nanostructures without complicated manipulation is still a challenge. In an effort to develop an alternative strategy of tellurization, herein we report a thin film formation of self-standing cobalt telluride nanotubes on various conducting and nonconducting substrates using a simple binder-free synthetic strategy based on anion exchange transformation from a thin film of cobalt hydroxycarbonate nanostructures in aqueous solution at room temperature. The nanostructured films before and after ion exchange transformation reaction are characterized using field emission scanning electron microscope, energy dispersive X-ray analyzer, X-ray photoelectron spectroscopy, thin film X-ray diffraction technique, high resolution transmission electron microscope, and selected area electron diffraction analysis technique. After the ion exchange transformation of nanostructures, the film shows conversion from insulator to highly electrical conductive semimetallic characteristic. When used as a counter electrode in I3(-)/I(-) redox electrolyte based dye-sensitized solar cells, the telluride film exhibits an electrocatalytic reduction activity for I3(-) with a demonstration of solar-light to electrical power conversion efficiency of 8.10%, which is highly competitive to the efficiency of 8.20% exhibited by a benchmarked Pt-film counter electrode. On the other hand, the telluride film electrode also demonstrates electrocatalytic activity for oxygen evolution reaction from oxidation of water.

  20. Bioavailability of cadmium from linseed and cocoa

    DEFF Research Database (Denmark)

    Hansen, Max; Sloth, Jens Jørgen; Rasmussen, Rie Romme

    In Denmark and EU the exposure of cadmium from food is at a level that is relatively close to the Tolerable Daily Intake (TDI). This report describes an investigation of the bioavailability of cadmium in selected food items known to contain high levels of cadmium. The purpose was to provide data ...... or crushed linseed nor the intake of cocoa and chocolate....

  1. Mechanisms of cadmium carcinogenesis

    International Nuclear Information System (INIS)

    Cadmium (Cd), a heavy metal of considerable occupational and environmental concern, has been classified as a human carcinogen by the International Agency for Research on Cancer (IARC). The carcinogenic potential of Cd as well as the mechanisms underlying carcinogenesis following exposure to Cd has been studied using in vitro cell culture and in vivo animal models. Exposure of cells to Cd results in their transformation. Administration of Cd in animals results in tumors of multiple organs/tissues. Also, a causal relationship has been noticed between exposure to Cd and the incidence of lung cancer in human. It has been demonstrated that Cd induces cancer by multiple mechanisms and the most important among them are aberrant gene expression, inhibition of DNA damage repair, induction of oxidative stress, and inhibition of apoptosis. The available evidence indicates that, perhaps, oxidative stress plays a central role in Cd carcinogenesis because of its involvement in Cd-induced aberrant gene expression, inhibition of DNA damage repair, and apoptosis.

  2. Feasibility of preparing patterned molybdenum coatings on bismuth telluride thermoelectric modules.

    Energy Technology Data Exchange (ETDEWEB)

    Sarobol, Pylin; Hall, Aaron Christopher; Miller, Stephen Samuel; Knight, Marlene E.; LePage, William S.; Sobczak, Catherine Elizabeth.; Wesolowski, Daniel Edward

    2013-09-01

    Molybdenum electrical interconnects for thermoelectric modules were produced by air plasma spraying a 30%CE%BCm size molybdenum powder through a laser-cut Kapton tape mask. Initial feasibility demonstrations showed that the molybdenum coating exhibited excellent feature and spacing retention (~170%CE%BCm), adhered to bismuth-telluride, and exhibited electrical conductivity appropriate for use as a thermoelectric module interconnect. A design of experiments approach was used to optimize air plasma spray process conditions to produce a molybdenum coating with low electrical resistivity. Finally, a molybdenum coating was successfully produced on a fullscale thermoelectric module. After the addition of a final titanium/gold layer deposited on top of the molybdenum coating, the full scale module exhibited an electrical resistivity of 128%CE%A9, approaching the theoretical resistivity value for the 6mm module leg of 112%CE%A9. Importantly, air plasma sprayed molybdenum did not show significant chemical reaction with bismuth-telluride substrate at the coating/substrate interface. The molybdenum coating microstructure consisted of lamellar splats containing columnar grains. Air plasma sprayed molybdenum embedded deeply (several microns) into the bismuth-telluride substrate, leading to good adhesion between the coating and the substrate. Clusters of round pores (and cracks radiating from the pores) were found immediately beneath the molybdenum coating. These pores are believed to result from tellurium vaporization during the spray process where the molten molybdenum droplets (2623%C2%B0C) transferred their heat of solidification to the substrate at the moment of impact. Substrate cooling during the molybdenum deposition process was recommended to mitigate tellurium vaporization in future studies.

  3. Lead telluride with increased mechanical stability for cylindrical thermoelectric generators; Bleitellurid mit erhoehter mechanischer Stabilitaet fuer zylindrische thermoelektrische Generatoren

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, Andreas

    2013-04-30

    The aim of this work is to improve the mechanical stability of lead telluride (PbTe), trying to vary its mechanical properties independently from its thermoelectric properties. Thus the influence of material preparation as well as different dopants on the mechanical and thermoelectric properties of lead telluride is being analysed. When using appropriately set process parameters, milling and sintering of lead telluride increases the material's hardness. With sintering temperatures exceeding 300 C stable material of high relative density can be achieved. Milling lead telluride generates lattice defects leading to a reduction of the material's charge carrier density. These defects can be reduced by increased sintering temperatures. Contamination of the powder due to the milling process leads to bloating during thermal cycling and thus reduced density of the sintered material. In addition to that, evaporation of tellurium at elevated temperatures causes instability of the material's thermoelectric properties. Based on the experimental results obtained in this work, the best thermoelectric and mechanical properties can be obtained by sintering coarse powders at around 400 C. Within this work a concept was developed to vary the mechanical properties of lead telluride via synthesis of PbTe with electrically nondoping elements, which thus may keep the thermoelectric properties unchanged. Therefore, the mechanical and thermoelectric properties of Pb{sub 1-x}Ca{sub x}Te were investigated. Doping pure PbTe with calcium causes a significant increase of the material's hardness while only slightly decreasing the charge carrier density and thus keeping the thermoelectric properties apart from a slight reduction of the electrical conductivity nearly unchanged. The abovementioned concept is proven using sodium doped lead telluride, as it is used for thermoelectric generators: The additional doping with calcium again increases the material's hardness while

  4. Polarity and structure peculiarities of trialkylphosphine oxides, sulfides, selenides and tellurides

    International Nuclear Information System (INIS)

    Using the quantum-chemical calculations structural characteristics of trialkylphosphine oxides, sulfates, selenides and tellurides (Alk3P=X; X O, S, Se, Te) are obtained, which are in good agreement with literature X-ray structural analysis and gas-phase electron diffraction data. The P=X bonds polarity is determined in the framework of vector-additive scheme on the base of experimental data on components dipole moments and using different base series of molecules geometry parameters. It is shown that increasing of bond moment P=X in the X = O, S, Se, Te series takes place through dipole length increasing

  5. Soft x-ray magnetic circular dichroism study of Cr tellurides

    OpenAIRE

    Yaji, Koichiro; Kimura, Akio; Koyama, Michie; Hirai, Chiyuki; Sato, Hitoshi; Shimada, Kenya; Tanaka, Arata; Taniguchi, Masaki

    2005-01-01

    Ferromagnetic chromium tellurides Cr5 Te6 (δ=0.17) and Cr2 Te3 (δ=0.33) have been investigated by Cr 2p x-ray absorption spectroscopy and x-ray magnetic circular dichroism (XMCD). The observed XMCD spectra have been analyzed by means of a configuration-interaction cluster model calculation. From calculated results, we suggest that the doped holes created by the Cr deficiency exist mainly in the Te 5p orbital of Cr1-δ Te.

  6. Oral cadmium chloride intoxication in mice

    DEFF Research Database (Denmark)

    Andersen, O; Nielsen, J B; Svendsen, P

    1988-01-01

    Diethyldithiocarbamate (DDC) is known to alleviate acute toxicity due to injection of cadmium salts. However, when cadmium chloride was administered by the oral route, DDC enhanced rather than alleviated the acute toxicity; both oral and intraperitoneal (i.p.) administration of DDC had this effect....... Thus, orally administered DDC enhanced cadmium-induced duodenal and ileal tissue damage and inhibition of peristalsis, as indicated by an increased intestinal transit time. At low cadmium doses, the whole-body retention of cadmium was increased by oral DDC administration. Intraperitoneally administered...

  7. Graphite-based photovoltaic cells

    Science.gov (United States)

    Lagally, Max; Liu, Feng

    2010-12-28

    The present invention uses lithographically patterned graphite stacks as the basic building elements of an efficient and economical photovoltaic cell. The basic design of the graphite-based photovoltaic cells includes a plurality of spatially separated graphite stacks, each comprising a plurality of vertically stacked, semiconducting graphene sheets (carbon nanoribbons) bridging electrically conductive contacts.

  8. Photovoltaic conversion of laser energy

    Science.gov (United States)

    Stirn, R. J.

    1976-01-01

    The Schottky barrier photovoltaic converter is suggested as an alternative to the p/n junction photovoltaic devices for the conversion of laser energy to electrical energy. The structure, current, output, and voltage output of the Schottky device are summarized. The more advanced concepts of the multilayer Schottky barrier cell and the AMOS solar cell are briefly considered.

  9. Arsenic-cadmium interaction in rats.

    Science.gov (United States)

    Díaz-Barriga, F; Llamas, E; Mejía, J J; Carrizales, L; Santoyo, M E; Vega-Vega, L; Yáñez, L

    1990-11-01

    Simultaneous exposure to cadmium and arsenic is highly probable in the urban area of San Luis Potosi, Mexico due to common localization of copper and zinc smelters. Therefore, in this work, rats were intraperitoneally exposed either to cadmium or arsenic alone, or simultaneously to both metals. The effects of these treatments on three different toxicological parameters were studied. Cadmium modified the LD50 of arsenic and conversely arsenic modified the LD50 for cadmium. At the histopathological level, arsenic appeared to protect against the cadmium effects, especially on testes. This protective effect seemed to be related to the glutathione levels found in this tissue: rats exposed to both arsenic and cadmium, presented glutathione values intermediate to those observed after exposure to either metal alone; arsenic had the highest value and cadmium the lowest. In liver, rats exposed to arsenic, cadmium or arsenic and cadmium, presented glutathione values below those in the saline group, with the lowest value corresponding to the arsenic and cadmium treatment. The results appear to support the proposed interaction between arsenic and cadmium and coexposure to both metals seems to alter certain effects produced by either metal alone. PMID:2219140

  10. Determination of cadmium in biological samples.

    Science.gov (United States)

    Klotz, Katrin; Weistenhöfer, Wobbeke; Drexler, Hans

    2013-01-01

    Analyses of cadmium concentrations in biological material are performed using inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption spectrometry (AAS), but also electrochemical methods, neutron activation analysis (NAA), and X-ray fluorescence spectrometry (XRF). The predominant sample matrices include blood, plasma, serum, and urine, as well as hair, saliva, and tissue of kidney cortex, lung, and liver. While cadmium in blood reveals rather the recent exposure situation, cadmium in urine reflects the body burden and is an indicator for the cumulative long term exposure.After chronic exposure, cadmium accumulates in the human body and causes kidney diseases, especially lesions of proximal tubular cells. A tubular proteinuria causes an increase in urinary excretion of microproteins. Excretions of retinol binding protein (RBP), β2-microglobulin (β2-M), and α1-microglobulin are validated biomarkers for analyzing cadmium effects. For this purpose, immunological procedures such as ELISA, and radio- and latex-immunoassays are used.However, proteinuria is not specific to cadmium, but can also occur after exposure to other nephrotoxic agents or due to various kidney diseases. In summary, cadmium in urine and blood are the most specific biomarkers of cadmium exposure. A combination of parameters of exposure (cadmium in blood, cadmium in urine) and parameters of effect (e.g., β2-M, RBP) is required to reveal cadmium-induced nephrological effects. PMID:23430771

  11. Insulin Expression in Rats Exposed to Cadmium

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objectives To investigate the effects of cadmium exposure on insulin expression in rats. Methods Eighteen adult SD assessed. The levels of cadmium and zinc in pancreas, blood and urine glucose, serum insulin and urine NAG (N-acyetyl-β-glucosaminidase) were determined. The gene expressions of metallothionein (MT) and insulin were also measured,and the oral glucose tolerance tests (OGTT) were carried out. Results The contents of cadmium in pancreas in cadmium-treated rats were higher than that in the control group, which was associated with slight increase of zinc in pancreas.not change significantly after cadmium administration, and the UNAG had no change in Cd-treated group. The gene expression the change of the expression of insulin, MT-Ⅰ and MT-Ⅱ genes. Cadmium can influence the biosynthesis of insulin, but does not induce the release of insulin. The dysfunction of pancreas occurs earlier than that of kidney after administration of cadmium.

  12. Lifetime of organic photovoltaics

    DEFF Research Database (Denmark)

    Corazza, Michael; Krebs, Frederik C; Gevorgyan, Suren A.

    2015-01-01

    tests. Comparison of the indoor and outdoor lifetimes was performed by means of the o-diagram, which constitutes the initial steps towards establishing a method for predicting the lifetime of an organic photovoltaic device under real operational conditions based on a selection of accelerated indoor......A comprehensive outdoor study of polymer solar cells and modules for duration of one year was conducted. Different sample geometries and encapsulations were employed in order to study the spread in the lifetimes. The study is a complimentary report to previous work that focused on indoor ageing...

  13. Optical waveguide enhanced photovoltaics.

    Science.gov (United States)

    Rühle, Sven; Greenwald, Shlomit; Koren, Elad; Zaban, Arie

    2008-12-22

    Enhanced light to electric power conversion efficiency of photovoltaic cells with a low absorbance was achieved using waveguide integration. We present a proof of concept using a very thin dye-sensitized solar cell which absorbed only a small fraction of the light at normal incidence. The glass substrate in conjunction with the solar cells reflecting back contact formed a planar waveguide, which lead to more than four times higher conversion efficiency compared to conventional illumination at normal incidence. This illumination concept leads to a new type of multi-junction PV systems based on enforced spectral splitting along the waveguide.

  14. Europe's space photovoltaics programme

    Science.gov (United States)

    Bogus, Klaus P.

    1994-01-01

    The current space PV (photovoltaic) technology development program of ESA is described. The program is closely coupled to the European space mission scenario for the next 10 year period and has as its main objective to make the most effective use of the limited resources available for technology in the present economical climate. This requires a well-balanced approach between concentration on very few options and keeping the competition alive if more than one promising technology exists. The paper describes ESA's main activities in the areas of solar array technology, solar cell technology, solar cell assembly technology, and special test and verification activities including the in-orbit demonstration of new technologies.

  15. Photovoltaic panel clamp

    Science.gov (United States)

    Mittan, Margaret Birmingham; Miros, Robert H. J.; Brown, Malcolm P.; Stancel, Robert

    2012-06-05

    A photovoltaic panel clamp includes an upper and lower section. The interface between the assembled clamp halves and the module edge is filled by a flexible gasket material, such as EPDM rubber. The gasket preferably has small, finger like protrusions that allow for easy insertion onto the module edge while being reversed makes it more difficult to remove them from the module once installed. The clamp includes mounting posts or an integral axle to engage a bracket. The clamp also may include a locking tongue to secure the clamp to a bracket.

  16. Photovoltaic concentrator module technology

    Science.gov (United States)

    Richards, Elizabeth H.; Chamberlin, Jay L.; Boes, Eldon C.

    Significant developments in the development of photovoltaic (PV) concentrator technology are described. Concentrator cell research, advances in PV concentrator cell technology, and PV concentrator module development are described. Reliability issues currently of concern, including the applicability of wet insulation resistance tests to concentrator modules, correlation of accelerated thermal cycling tests with life expectancy in the field, and the importance of quality assurance during manufacture, are discussed. Two PV concentrator power systems installed in 1989 are discussed. A PV concentrator initiative program established by the DOE is given, and the results of the latest cost study are presented.

  17. Canadian photovoltaic industry directory

    International Nuclear Information System (INIS)

    This directory has been prepared to help potential photovoltaic (PV) customers identify Canadian-based companies who can meet their needs, and to help product manufacturers and distributors identify potential new clients and/or partners within the PV industry for new and improved technologies. To assist the reader, an information matrix is provided that identifies the product and service types offered by each firm and its primary clients served. A list of companies by province or territory is also included. The main section lists companies in alphabetical order. Information presented for each includes address, contact person, prime activity, geographic area served, languages in which services are offered, and a brief company profile

  18. Photonics in photovoltaic systems

    Energy Technology Data Exchange (ETDEWEB)

    Gombert, Andreas [Concentrix Solar GmbH, Boetzinger Str. 31, 79111 Freiburg (Germany); Luque, Antonio [Universidad Politecnica de Madrid, Instituto de Energia Solar, 28040 Madrid (Spain)

    2008-12-15

    This paper gives an overview on photonics for photovoltaic systems. Starting from the spectral and angular distribution of the electromagnetic radiation from the sun, many important optical approaches how to improve the efficiency of solar cells are presented and discussed. Topics include antireflective coatings, various light trapping structures, refractive, reflective and fluorescent concentrators, and components for spectral management. The theoretical background is shortly described and examples of the experimental and also of the commercial realisation are given. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. Photovoltaic Degradation Risk: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, D. C.; Kurtz, S. R.

    2012-04-01

    The ability to accurately predict power delivery over the course of time is of vital importance to the growth of the photovoltaic (PV) industry. Important cost drivers include the efficiency with which sunlight is converted into power, how this relationship changes over time, and the uncertainty in this prediction. An accurate quantification of power decline over time, also known as degradation rate, is essential to all stakeholders - utility companies, integrators, investors, and researchers alike. In this paper we use a statistical approach based on historical data to quantify degradation rates, discern trends and quantify risks related to measurement uncertainties, number of measurements and methodologies.

  20. Steady-State Screening-Photovoltaic Spatial Solitons in the Biased Photorefractive-Photovoltaic Crystals

    Institute of Scientific and Technical Information of China (English)

    LU Ke-Qing; ZHANG Yan-Peng; TANG Tian-Tong; LU Zhi-Xian; LIU Lin

    2001-01-01

    The theory of the screening-photovoltaic solitons is improved in biased photorefractive-photovoltaic crystals. When the photovoltaic effect is negligible, the screening-photovoltaic solitons are the screening ones, and their space-charge field is the space-charge field of the screening solitons. If the external field is absent, the screening photovoltaic solitons are the photovoltaic ones on the open- and closed-circuit conditions, and their space-charge field is of the photovoltaic solitons. We also show theoretically that the screening and the photovoltaic solitons on the open- and closed-circuit conditions may be studies together as the screening-photovoltaic solitons.

  1. Experimental investigation to evaluate the potential environmental hazards of photovoltaic panels.

    Science.gov (United States)

    Tammaro, Marco; Salluzzo, Antonio; Rimauro, Juri; Schiavo, Simona; Manzo, Sonia

    2016-04-01

    Recently the potential environmental hazard of photovoltaic modules together with their management as waste has attracted the attention of scientists. Particular concern is aroused by the several metals contained in photovoltaic panels whose potential release in the environment were scarcely investigated. Here, for the first time, the potential environmental hazard of panels produced in the last 30 years was investigated through the assessment of up to 18 releasable metals. Besides, the corresponding ecotoxicological effects were also evaluated. Experimental data were compared with the current European and Italian law limits for drinking water, discharge on soil and landfill inert disposal in order to understand the actual pollution load. Results showed that less than 3% of the samples respected all law limits and around 21% was not ecotoxic. By considering the technological evolutions in manufacturing, we have shown that during the years crystalline silicon panels have lower tendency to release hazardous metals with respect to thin film panels. In addition, a prediction of the amounts of lead, chromium, cadmium and nickel releasable from next photovoltaic waste was performed. The prevision up to 2050 showed high amounts of lead (30t) and cadmium (2.9t) releasable from crystalline and thin film panels respectively.

  2. Thermoelectric properties and micro-structure characteristics of annealed N-type bismuth telluride thin film

    International Nuclear Information System (INIS)

    N-type bismuth telluride (Bi2Te3) thermoelectric thin films were deposited by co-sputtering simple substance Te and Bi targets. The deposited films were annealed under various temperatures. The composition ratio, micro-structure and thermoelectric properties of the prepared films were systematically investigated by energy dispersive spectrometer, X-ray diffraction, four-probe method and Seebeck coefficient measurement system. When the annealing temperature is 400 °C, the stoichiometric N-type Bi2Te3 film is achieved, which has a maximum thermoelectric power factor of 0.821 × 10−3 W m−1 K−2. Furthermore, the dependence of Seebeck coefficient, electrical conductivity and power factor of the stoichiometric N-type Bi2Te3 film annealed at film 400 °C on the applied temperature ranging from 25 °C to 315 °C was investigated. The results show that a highest power factor of 3.288 × 10−3 W m−1 K−2 is obtained at the applied temperature of 275 °C. The structural and thermoelectric properties of the deposited bismuth telluride thin films are greatly improved by annealing and the Seebeck coefficient, electrical conductivity and power factor increase with the applied temperature rising, which are helpful and could be guidance for preparing the high-performance thin film thermoelectric materials for thermoelectric application.

  3. Facile production of thermoelectric bismuth telluride thick films in the presence of polyvinyl alcohol.

    Science.gov (United States)

    Lei, C; Burton, M R; Nandhakumar, I S

    2016-06-01

    Bismuth telluride is currently the best performing thermoelectric material for room temperature operations in commercial thermoelectric devices. We report the reproducible and facile production of 600 micron thick bismuth telluride (Bi2Te3) layers by low cost and room temperature pulsed and potentiostatic electrodeposition from a solution containing bismuth and tellurium dioxide in 2 M nitric acid onto nickel in the presence of polyvinyl alcohol (PVA). This was added to the electrolyte to promote thick layer formation and its effect on the structure, morphology and composition of the electrodeposits was investigated by SEM and EDX. Well adherent, uniform, compact and stoichiometric n-type Bi2Te3 films with a high Seebeck coefficient of up to -200 μV K(-1) and a high electrical conductivity of up to 400 S cm(-1) resulting in a power factor of 1.6 × 10(-3) W m(-1) K(-2) at film growth rates of 100 μm h(-1) for potentiostatic electrodeposition were obtained. The films also exhibited a well defined hexagonal structure as determined by XRD.

  4. Telluride buried channel waveguides operating from 6 to 20 μm for photonic applications

    Science.gov (United States)

    Vigreux, C.; Escalier, R.; Pradel, A.; Bastard, L.; Broquin, J.-E.; Zhang, X.; Billeton, T.; Parent, G.; Barillot, M.; Kirschner, V.

    2015-11-01

    One of the technological challenges of direct observation of extra-solar planets by nulling interferometry is the development of a modal filter operating from 6 to 20 μm. In the present paper a candidate technology for the fabrication of such modal filters is presented: Integrated Optics. A solution based on all-telluride buried channel waveguides is considered. In the proposed waveguides, vertical guiding of light is achieved by a 15 μm-thick Te83Ge17 core film deposited onto a lower-index Te75Ge15Ga10 substrate, and covered by a 15 μm-thick Te76Ge24 superstrate. Horizontal guiding of light is obtained by modifying the geometry of the core layer by ion beam etching. As this stage, all-telluride buried channel waveguide prototypes demonstrate light guiding and transmission from 2 to 20 μm. The validity of the technology and the good quality of the fabrication process, in particular the input and output facets surface finish are thus confirmed. These results consolidate the potential of Te-based integrated optics components for nulling interferometry.

  5. A density-functional study on the electronic and vibrational properties of layered antimony telluride

    Science.gov (United States)

    Stoffel, Ralf P.; Deringer, Volker L.; Simon, Ronnie E.; Hermann, Raphaël P.; Dronskowski, Richard

    2015-03-01

    We present a comprehensive survey of electronic and lattice-dynamical properties of crystalline antimony telluride (Sb2Te3). In a first step, the electronic structure and chemical bonding have been investigated, followed by calculations of the atomic force constants, phonon dispersion relationships and densities of states. Then, (macroscopic) physical properties of Sb2Te3 have been computed, namely, the atomic thermal displacement parameters, the Grüneisen parameter γ, the volume expansion of the lattice, and finally the bulk modulus B. We compare theoretical results from three popular and economic density-functional theory (DFT) approaches: the local density approximation (LDA), the generalized gradient approximation (GGA), and a posteriori dispersion corrections to the latter. Despite its simplicity, the LDA shows excellent performance for all properties investigated—including the Grüneisen parameter, which only the LDA is able to recover with confidence. In the absence of computationally more demanding hybrid DFT methods, the LDA seems to be a good choice for further lattice dynamical studies of Sb2Te3 and related layered telluride materials.

  6. Incoherently Coupled Grey Photovoltaic Spatial Soliton Families

    Institute of Scientific and Technical Information of China (English)

    WANG Hong-Cheng; SHE Wei-Long

    2005-01-01

    @@ A theory is developed for incoherently coupled grey photovoltaic soliton families in unbiased photovoltaic crystals.Both the properties and the forming conditions of these soliton families are discussed in detail The theory canalso be used to investigate the dark photovoltaic soliton families. Some relevant examples are presented, in which the photovoltaic-photorefractive crystal is of lithium niobate type.

  7. Effect of Annealing on the Properties of Antimony Telluride Thin Films and Their Applications in CdTe Solar Cells

    Directory of Open Access Journals (Sweden)

    Zhouling Wang

    2014-01-01

    Full Text Available Antimony telluride alloy thin films were deposited at room temperature by using the vacuum coevaporation method. The films were annealed at different temperatures in N2 ambient, and then the compositional, structural, and electrical properties of antimony telluride thin films were characterized by X-ray fluorescence, X-ray diffraction, differential thermal analysis, and Hall measurements. The results indicate that single phase antimony telluride existed when the annealing temperature was higher than 488 K. All thin films exhibited p-type conductivity with high carrier concentrations. Cell performance was greatly improved when the antimony telluride thin films were used as the back contact layer for CdTe thin film solar cells. The dark current voltage and capacitance voltage measurements were performed to investigate the formation of the back contacts for the cells with or without Sb2Te3 buffer layers. CdTe solar cells with the buffer layers can reduce the series resistance and eliminate the reverse junction between CdTe and metal electrodes.

  8. Photovoltaic programme, edition 2004

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    This comprehensive publication issued by the Swiss Federal Office of Energy's Photovoltaics (PV) Programme presents an overview (in English) of activities and projects in the photovoltaics research and pilot and demonstration areas in Switzerland for the year 2003. Progress in future solar cell technologies as well as in the area of modules, building integration and system technologies is summarised. Also, national and international co-operation and multi-national pilot and demonstration projects are commented on. Associated projects such as eco-balances for PV systems, forecasting and modelling tools as well as system monitoring tools are discussed. In the area of pilot and demonstration projects, component development, PV integration in sloping roofs, on flat roofs and on facades as well as further PV plant are looked at. Also, measurement campaigns, studies, statistics and other PV-related topics are summarised. This volume presents a list of 92 projects in the PV area including the appropriate Internet links and is completed with a collection of project abstracts.

  9. Photovoltaics information user study

    Energy Technology Data Exchange (ETDEWEB)

    Belew, W.W.; Wood, B.L.; Marie, T.L.; Reinhardt, C.L.

    1980-10-01

    The results of a series of telephone interviews with groups of users of information on photovoltaics (PV) are described. These results, part of a larger study on many different solar technologies, identify types of information each group needed and the best ways to get information to each group. The report is 1 of 10 discussing study results. The overall study provides baseline data about information needs in the solar community. It covers these technological areas: photovoltaics, passive solar heating and cooling, active solar heating and cooling, biomass energy, solar thermal electric power, solar industrial and agricultural process heat, wind energy, ocean energy, and advanced energy storage. An earlier study identified the information user groups in the solar community and the priority (to accelerate solar energy commercialization) of getting information to each group. In the current study only high-priority groups were examined. Results from seven PV groups respondents are analyzed in this report: DOE-Funded Researchers, Non-DOE-Funded Researchers, Researchers Working for Manufacturers, Representatives of Other Manufacturers, Representatives of Utilities, Electric Power Engineers, and Educators.

  10. Photovoltaic Product Directory and Buyers Guide

    Energy Technology Data Exchange (ETDEWEB)

    Watts, R.L.; Smith, S.A.; Dirks, J.A.; Mazzucchi, R.P.; Lee, V.E.

    1984-04-01

    The directory guide explains photovoltaic systems briefly and shows what products are available off-the-shelf. Information is given to assist in designing a photovoltaic system and on financial incentives. Help is given for determining if photovoltaic products can meet a particular buyer's needs, and information is provided on actual photovoltaic user's experiences. Detailed information is appended on various financial incentives available from state and federal governments, sources of additional information on photovoltaics, sources of various photovoltaic products, and a listing of addresses of photovoltaic products suppliers. (LEW)

  11. Parametric study of laser photovoltaic energy converters

    Science.gov (United States)

    Walker, G. H.; Heinbockel, J. H.

    1987-01-01

    Photovoltaic converters are of interest for converting laser power to electrical power in a space-based laser power system. This paper describes a model for photovoltaic laser converters and the application of this model to a neodymium laser silicon photovoltaic converter system. A parametric study which defines the sensitivity of the photovoltaic parameters is described. An optimized silicon photovoltaic converter has an efficiency greater than 50 percent for 1000 W/sq cm of neodymium laser radiation.

  12. Optimization of photovoltaic power systems

    CERN Document Server

    Rekioua, Djamila

    2012-01-01

    Photovoltaic generation is one of the cleanest forms of energy conversion available. One of the advantages offered by solar energy is its potential to provide sustainable electricity in areas not served by the conventional power grid. Optimisation of Photovoltaic Power Systems details explicit modelling, control and optimisation of the most popular stand-alone applications such as pumping, power supply, and desalination. Each section is concluded by an example using the MATLAB(R) and Simulink(R) packages to help the reader understand and evaluate the performance of different photovoltaic syste

  13. Photovoltaic module with adhesion promoter

    Science.gov (United States)

    Xavier, Grace

    2013-10-08

    Photovoltaic modules with adhesion promoters and methods for fabricating photovoltaic modules with adhesion promoters are described. A photovoltaic module includes a solar cell including a first surface and a second surface, the second surface including a plurality of interspaced back-side contacts. A first glass layer is coupled to the first surface by a first encapsulating layer. A second glass layer is coupled to the second surface by a second encapsulating layer. At least a portion of the second encapsulating layer is bonded directly to the plurality of interspaced back-side contacts by an adhesion promoter.

  14. Silicon processing for photovoltaics II

    CERN Document Server

    Khattak, CP

    2012-01-01

    The processing of semiconductor silicon for manufacturing low cost photovoltaic products has been a field of increasing activity over the past decade and a number of papers have been published in the technical literature. This volume presents comprehensive, in-depth reviews on some of the key technologies developed for processing silicon for photovoltaic applications. It is complementary to Volume 5 in this series and together they provide the only collection of reviews in silicon photovoltaics available.The volume contains papers on: the effect of introducing grain boundaries in silicon; the

  15. Cadmium detoxification processes in the digestive gland of cephalopods in relation to accumulated cadmium concentrations

    OpenAIRE

    Bustamante, Paco; Cosson, Richard; Gallien, Isabelle; Caurant, Florence; Miramand, Pierre

    2002-01-01

    International audience The high concentrations of cadmium recorded in the digestive gland of cephalopods from various temperate and subpolar waters suggest that these molluscs have developed efficient cadmium detoxification mechanisms. The subcellular distribution of cadmium in the digestive gland cells was investigated in seven cephalopod species from the Bay of Biscay (France) and the Faroe Islands. In most species, cadmium was mainly found in the cytosolic fraction of the digestive glan...

  16. Cadmium content of plants as affected by soil cadmium concentration

    Energy Technology Data Exchange (ETDEWEB)

    Lehoczky, E. [Pannon Univ. of Agricultural Sciences, Keszthely (Hungary); Szabados, I.; Marth, P. [Plant Health and Soil Conservation Station, Higany (Hungary)

    1996-12-31

    Pot experiments were conducted in greenhouse conditions to study the effects of increasing cadmium (Cd) levels on biomass production and Cd contents in corn, (Zea mays L.), garlic (Allium sativum L.), and spinach (Spinacia oleracea L.). Plants were grown in two soil types: Eutric cambisol soil and A gleyic luvisol soil. Spinach proved to be the most sensitive to Cd treatments as its biomass considerably decreased with the increasing Cd levels. Cadmium contents of the three crops increased with increasing levels of Cd applications. Statistical differences were observed in the Cd contents of crops depending on soil type. With the same Cd rates, Cd tissue concentration of test plants grown in the strongly acidic Gleyic luvisol soil were many times higher than that of plants grown in a neutral Eutric cambisol soil. 14 refs., 4 tabs.

  17. Polymer Photovoltaic Cells

    Institute of Scientific and Technical Information of China (English)

    Jianhui Hou; Chunhe Yang; Erjun Zhou; Chang He; Zhan'ao Tan; Youjun He; Yongfang Li

    2005-01-01

    @@ 1Introduction Polymer photovoltaic cells (PPVCs) have attracted much attention recently because of its easy fabrication, low cost and possibility to make flexible devices[1]. PPVC is composed of a conjugated polymer/C60blend layer (photosensitive layer) sandwiched between a transparent ITO electrode and a metal electrode.When a light through ITO electrode irradiates on the photosensitive layer, the photons with appropriate energy will be absorbed by the conjugated polymer (CP) and excitons (electron-hole pair) are produced. The excitons move to the interface of CP/C60 where the electrons transfer to the LUMO of C60 and holes leave on the HOMO of the CP. The separated electrons migrate through the C60 network to and are collected by the metal electrode, and the holes migrate through the CP network to and are collected by the ITO electrode, so that the photocurrent and photovoltage are attained.

  18. Photovoltaics Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-02-01

    This fact sheet is an overview of the Photovoltaics (PV) subprogram at the U.S. Department of Energy SunShot Initiative. The U.S. Department of Energy (DOE)’s Solar Energy Technologies Office works with industry, academia, national laboratories, and other government agencies to advance solar PV, which is the direct conversion of sunlight into electricity by a semiconductor, in support of the goals of the SunShot Initiative. SunShot supports research and development to aggressively advance PV technology by improving efficiency and reliability and lowering manufacturing costs. SunShot’s PV portfolio spans work from early-stage solar cell research through technology commercialization, including work on materials, processes, and device structure and characterization techniques.

  19. Photovoltaic module mounting system

    Science.gov (United States)

    Miros, Robert H. J.; Mittan, Margaret Birmingham; Seery, Martin N.; Holland, Rodney H.

    2012-04-17

    A solar array mounting system having unique installation, load distribution, and grounding features, and which is adaptable for mounting solar panels having no external frame. The solar array mounting system includes flexible, pedestal-style feet and structural links connected in a grid formation on the mounting surface. The photovoltaic modules are secured in place via the use of attachment clamps that grip the edge of the typically glass substrate. The panel mounting clamps are then held in place by tilt brackets and/or mid-link brackets that provide fixation for the clamps and align the solar panels at a tilt to the horizontal mounting surface. The tilt brackets are held in place atop the flexible feet and connected link members thus creating a complete mounting structure.

  20. Photovoltaic solar concentrator

    Energy Technology Data Exchange (ETDEWEB)

    Nielson, Gregory N.; Gupta, Vipin P.; Okandan, Murat; Watts, Michael R.

    2016-03-15

    A photovoltaic solar concentrator is disclosed with one or more transverse-junction solar cells (also termed point contact solar cells) and a lens located above each solar cell to concentrate sunlight onto the solar cell to generate electricity. Piezoelectric actuators tilt or translate each lens to track the sun using a feedback-control circuit which senses the electricity generated by one or more of the solar cells. The piezoelectric actuators can be coupled through a displacement-multiplier linkage to provide an increased range of movement of each lens. Each lens in the solar concentrator can be supported on a frame (also termed a tilt plate) having three legs, with the movement of the legs being controlled by the piezoelectric actuators.

  1. Photovoltaic solar concentrator

    Science.gov (United States)

    Nielson, Gregory N.; Okandan, Murat; Resnick, Paul J.; Cruz-Campa, Jose Luis

    2012-12-11

    A photovoltaic solar concentrator is disclosed with one or more transverse-junction solar cells (also termed point contact solar cells) and a lens located above each solar cell to concentrate sunlight onto the solar cell to generate electricity. Piezoelectric actuators tilt or translate each lens to track the sun using a feedback-control circuit which senses the electricity generated by one or more of the solar cells. The piezoelectric actuators can be coupled through a displacement-multiplier linkage to provide an increased range of movement of each lens. Each lens in the solar concentrator can be supported on a frame (also termed a tilt plate) having three legs, with the movement of the legs being controlled by the piezoelectric actuators.

  2. Photovoltaic solar cell

    Science.gov (United States)

    Nielson, Gregory N.; Gupta, Vipin P.; Okandan, Murat; Watts, Michael R.

    2015-09-08

    A photovoltaic solar concentrator is disclosed with one or more transverse-junction solar cells (also termed point contact solar cells) and a lens located above each solar cell to concentrate sunlight onto the solar cell to generate electricity. Piezoelectric actuators tilt or translate each lens to track the sun using a feedback-control circuit which senses the electricity generated by one or more of the solar cells. The piezoelectric actuators can be coupled through a displacement-multiplier linkage to provide an increased range of movement of each lens. Each lens in the solar concentrator can be supported on a frame (also termed a tilt plate) having three legs, with the movement of the legs being controlled by the piezoelectric actuators.

  3. Photovoltaic spectral responsivity measurements

    Energy Technology Data Exchange (ETDEWEB)

    Emery, K.; Dunlavy, D.; Field, H.; Moriarty, T. [National Renewable Energy Lab., Golden, CO (United States)

    1998-09-01

    This paper discusses the various elemental random and nonrandom error sources in typical spectral responsivity measurement systems. The authors focus specifically on the filter and grating monochrometer-based spectral responsivity measurement systems used by the Photovoltaic (PV) performance characterization team at NREL. A variety of subtle measurement errors can occur that arise from a finite photo-current response time, bandwidth of the monochromatic light, waveform of the monochromatic light, and spatial uniformity of the monochromatic and bias lights; the errors depend on the light source, PV technology, and measurement system. The quantum efficiency can be a function of he voltage bias, light bias level, and, for some structures, the spectral content of the bias light or location on the PV device. This paper compares the advantages and problems associated with semiconductor-detector-based calibrations and pyroelectric-detector-based calibrations. Different current-to-voltage conversion and ac photo-current detection strategies employed at NREL are compared and contrasted.

  4. All-Oxide Photovoltaics.

    Science.gov (United States)

    Rühle, Sven; Anderson, Assaf Y; Barad, Hannah-Noa; Kupfer, Benjamin; Bouhadana, Yaniv; Rosh-Hodesh, Eli; Zaban, Arie

    2012-12-20

    Recently, a new field in photovoltaics (PV) has emerged, focusing on solar cells that are entirely based on metal oxide semiconductors. The all-oxide PV approach is very attractive due to the chemical stability, nontoxicity, and abundance of many metal oxides that potentially allow manufacturing under ambient conditions. Already today, metal oxides (MOs) are widely used as components in PV cells such as transparent conducting front electrodes or electron-transport layers, while only very few MOs have been used as light absorbers. In this Perspective, we review recent developments of all-oxide PV systems, which until today were mostly based on Cu2O as an absorber. Furthermore, ferroelectric BiFeO3-based PV systems are discussed, which have recently attracted considerable attention. The performance of all-oxide PV cells is discussed in terms of general PV principles, and directions for progress are proposed, pointing toward the development of novel metal oxide semiconductors using combinatorial methods.

  5. Photovoltaic cell assembly

    Science.gov (United States)

    Beavis, Leonard C.; Panitz, Janda K. G.; Sharp, Donald J.

    1990-01-01

    A photovoltaic assembly for converting high intensity solar radiation into lectrical energy in which a solar cell is separated from a heat sink by a thin layer of a composite material which has excellent dielectric properties and good thermal conductivity. This composite material is a thin film of porous Al.sub.2 O.sub.3 in which the pores have been substantially filled with an electrophoretically-deposited layer of a styrene-acrylate resin. This composite provides electrical breakdown strengths greater than that of a layer consisting essentially of Al.sub.2 O.sub.3 and has a higher thermal conductivity than a layer of styrene-acrylate alone.

  6. Photovoltaic building blocks

    DEFF Research Database (Denmark)

    Hanberg, Peter Jesper; Jørgensen, Anders Michael

    2014-01-01

    it directcompetitive with fossil energy sources a further reduction is needed. By increasing the efficiency of the solar cells one gain an advantage through the whole chain of cost. So that per produced Watt of power less material is spent, installation costs are lower, less area is used etc. With an average...... efficiency of about 15% for commercial Silicon solar cells there is still much to gain. DTU Danchip provides research facilities, equipment and expertise for the building blocks that comprises fabricating the efficient solar cell. In order to get more of the sun light into the device we provide thin film......Photovoltaics (PV), better known as solar cells, are now a common day sight on many rooftops in Denmark.The installed capacity of PV systems worldwide is growing exponentially1 and is the third most importantrenewable energy source today. The cost of PV is decreasing fast with ~10%/year but to make...

  7. The solar photovoltaic

    International Nuclear Information System (INIS)

    This publication first outlines challenges and stakes related to the development of renewable energies, and more particularly of photovoltaic solar energy in France and in the World. Principles and applications (connected and autonomous systems) are briefly presented. Some key data regarding installed capacity and its evolution in France and in other countries are briefly commented. The knowledge status of this technology is discussed in terms of strengths (environmental and energetic benefits, modularity, fast decreasing costs, integration into building envelope, local investment and consumer commitment, an added value and job generating sector), and weaknesses (fluctuating production and impact on the supply-demand balance, local impact on the distribution grid, land use, cautions, a sector with some environmental impact, evolutions of the support arrangement in France). Actions undertaken by the ADEME in different areas (support to research and innovation, installation quality, promotion of technologies with less environmental impacts) are reviewed

  8. Cadmium Exposure and Pancreatic Cancer in South Louisiana

    OpenAIRE

    Luckett, Brian G.; L. Joseph Su; Rood, Jennifer C.; Elizabeth T. H. Fontham

    2012-01-01

    Cadmium has been hypothesized to be a pancreatic carcinogen. We test the hypothesis that cadmium exposure is a risk factor for pancreatic cancer with a population-based case-control study sampled from a population with persistently high rates of pancreatic cancer (south Louisiana). We tested potential dietary and nondietary sources of cadmium for their association with urinary cadmium concentrations which reflect long-term exposure to cadmium due to the accumulation of cadmium in the kidney c...

  9. Photovoltaic sources modeling and emulation

    CERN Document Server

    Piazza, Maria Carmela Di

    2012-01-01

    This book offers an extensive introduction to the modeling of photovoltaic generators and their emulation by means of power electronic converters will aid in understanding and improving design and setup of new PV plants.

  10. Penetration of Photovoltaics in Greece

    Directory of Open Access Journals (Sweden)

    Eugenia Giannini

    2015-06-01

    Full Text Available Recently, an interesting experiment was completed in Greece concerning photovoltaic penetration into the electricity production sector. Based on the relevant laws and in accordance to the related European directives, an explosive penetration process was completed in less than three years, resulting in a 7% share of photovoltaics in electricity production instead of the previous negligible share. The legislation was based on licensing simplification and generous feed-in-tariffs. This approach transformed photovoltaic technology from a prohibitively expensive to a competitive one. This work aims to summarize the relevant legislation and illustrate its effect on the resulting penetration. A sigmoid-shape penetration was observed which was explained by a pulse-type driving force. The return on investment indicator was proposed as an appropriate driving force, which incorporates feed-in-tariffs and turnkey-cost. Furthermore, the resulting surcharge on the electricity price due to photovoltaic penetration was also analyzed.

  11. Zone refining of cadmium and related characterization

    Indian Academy of Sciences (India)

    N R Munirathnam; D S Prasad; Ch Sudheer; J V Rao; T L Prakash

    2005-06-01

    We present the zone refining results of cadmium using horizontal resistive zone refiner under constant flow of moisture free hydrogen gas. The boron impurity in cadmium can be avoided using quartz (GE 214 grade) boat in lieu of high pure graphite boat. The analytical results using inductively coupled plasma optical emission spectrometry (ICPOES) show that majority of the impurities are less than the detection limits. Comparatively, zinc is the most difficult impurity element to remove in cadmium matrix by zone refining.

  12. Electrodialytic Removal of Cadmium from Straw Ash

    DEFF Research Database (Denmark)

    Hansen, Henrik; Ottosen, Lisbeth M.; Villumsen, Arne;

    1999-01-01

    A problem with flyash from straw and wood combustion is the high level of heavy metals, especially cadmium. Two electrodialytic remediation experiments were carried out on cadmium polluted flyash from straw combustion. The flyash could be cleaned to 1/3 of its initial level after 24 days...... of remediation. Further removal of cadmium could be possible with longer remediation time or a higher current density...

  13. Solid State Photovoltaic Research Branch

    Energy Technology Data Exchange (ETDEWEB)

    1990-09-01

    This report summarizes the progress of the Solid State Photovoltaic Research Branch of the Solar Energy Research Institute (SERI) from October 1, 1988, through September 30,l 1989. Six technical sections of the report cover these main areas of SERIs in-house research: Semiconductor Crystal Growth, Amorphous Silicon Research, Polycrystalline Thin Films, III-V High-Efficiency Photovoltaic Cells, Solid-State Theory, and Laser Raman and Luminescence Spectroscopy. Sections have been indexed separately for inclusion on the data base.

  14. Mathematical Model for Photovoltaic Cells

    OpenAIRE

    Wafaa ABD EL-BASIT; Ashraf Mosleh ABD El–MAKSOOD; Fouad Abd El-Moniem Saad SOLIMAN

    2013-01-01

    The study of photovoltaic systems in an efficient manner requires a precise knowledge of the (I-V) and (P-V) characteristic curves of photovoltaic modules. So, the aim of the present paper is to estimate such characteristics based on different operating conditions. In this concern, a simple one diode mathematical model was implemented using MATLAB script. The output characteristics of PV cell depend on the environmental conditions. For any solar cell, the model parameters are function of the ...

  15. Natural Flow Air Cooled Photovoltaics

    Science.gov (United States)

    Tanagnostopoulos, Y.; Themelis, P.

    2010-01-01

    Our experimental study aims to investigate the improvement in the electrical performance of a photovoltaic installation on buildings through cooling of the photovoltaic panels with natural air flow. Our experimental study aims to investigate the improvement in the electrical performance of a photovoltaic installation on buildings through cooling of the photovoltaic panels with natural air flow. We performed experiments using a prototype based on three silicon photovoltaic modules placed in series to simulate a typical sloping building roof with photovoltaic installation. In this system the air flows through a channel on the rear side of PV panels. The potential for increasing the heat exchange from the photovoltaic panel to the circulating air by the addition of a thin metal sheet (TMS) in the middle of air channel or metal fins (FIN) along the air duct was examined. The operation of the device was studied with the air duct closed tightly to avoid air circulation (CLOSED) and the air duct open (REF), with the thin metal sheet (TMS) and with metal fins (FIN). In each case the experiments were performed under sunlight and the operating parameters of the experimental device determining the electrical and thermal performance of the system were observed and recorded during a whole day and for several days. We collected the data and form PV panels from the comparative diagrams of the experimental results regarding the temperature of solar cells, the electrical efficiency of the installation, the temperature of the back wall of the air duct and the temperature difference in the entrance and exit of the air duct. The comparative results from the measurements determine the improvement in electrical performance of the photovoltaic cells because of the reduction of their temperature, which is achieved by the naturally circulating air.

  16. Photovoltaic application in modern agriculture

    OpenAIRE

    Wang, Huaxin; Muñoz Garcia, Miguel Angel; Moreda Cantero, Guillermo P.

    2015-01-01

    The use of photovoltaic (PV) electricity in modern agriculture has shown its advantages since the 1970s when it was possible to obtain a substantial green energy without the pollution by burning fossil fuels (coal, oil or natural gas) or the threaten of nuclear accident. Due to the price descent of the PV system, some new applications are becoming economically attractive, like the combination of PV and agriculture. Meanwhile, the use of agricultural soils contributes to making photovoltaic a ...

  17. Handbook of secondary storage batteries and charge regulators in photovoltaic systems. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1981-08-01

    Solar photovoltaic systems often require battery subsystems to store reserve electrical energy for times of zero insolation. This handbook is designed to help the system designer make optimum choices of battery type, battery size and charge control circuits. Typical battery performance characteristics are summarized for four types of lead-acid batteries: pure lead, lead-calcium and lead-antimony pasted flat plate and lead-antimony tubular positive types. Similar data is also provided for pocket plate nickel cadmium batteries. Economics play a significant role in battery selection. Relative costs of each battery type are summarized under a variety of operating regimes expected for solar PV installations.

  18. Bioavailability of cadmium from linseed and cocoa

    OpenAIRE

    Hansen, Max; Rasmussen, Rie Romme; Sloth, Jens Jørgen

    2014-01-01

    The exposure of the European population to cadmium from food is high compared with the tolerable weekly intake of 2.5 μg/kg bodyweight set by EFSA in 2009. Only few studies on the bioavailability of cadmium from different food sources has been performed but this information in very important for the food authorities in order to give correct advises to the population. The aim of this study was to investigate the bioavailability of cadmium from whole linseed, crushed linseed, cocoa and cadmium ...

  19. The Epigenetic Effects of Prenatal Cadmium Exposure.

    Science.gov (United States)

    Vilahur, Nadia; Vahter, Marie; Broberg, Karin

    2015-06-01

    Prenatal exposure to the highly toxic and common pollutant cadmium has been associated with adverse effects on child health and development. However, the underlying biological mechanisms of cadmium toxicity remain partially unsolved. Epigenetic disruption due to early cadmium exposure has gained attention as a plausible mode of action, since epigenetic signatures respond to environmental stimuli and the fetus undergoes drastic epigenomic rearrangements during embryogenesis. In the current review, we provide a critical examination of the literature addressing prenatal cadmium exposure and epigenetic effects in human, animal, and in vitro studies. We conducted a PubMed search and obtained eight recent studies addressing this topic, focusing almost exclusively on DNA methylation. These studies provide evidence that cadmium alters epigenetic signatures in the DNA of the placenta and of the newborns, and some studies indicated marked sexual differences for cadmium-related DNA methylation changes. Associations between early cadmium exposure and DNA methylation might reflect interference with de novo DNA methyltransferases. More studies, especially those including environmentally relevant doses, are needed to confirm the toxicoepigenomic effects of prenatal cadmium exposure and how that relates to the observed health effects of cadmium in childhood and later life.

  20. LIFE CYCLE INVENTORY ANALYSIS IN THE PRODUCTION OF METALS USED IN PHOTOVOLTAICS.

    Energy Technology Data Exchange (ETDEWEB)

    FTHENAKIS,V.M.; KIM, H.C.; WANG, W.

    2007-03-30

    Material flows and emissions in all the stages of production of zinc, copper, aluminum, cadmium, indium, germanium, gallium, selenium, tellurium, and molybdenum were investigated. These metals are used selectively in the manufacture of solar cells, and emission and energy factors in their production are used in the Life Cycle Analysis (LCA) of photovoltaics. Significant changes have occurred in the production and associated emissions for these metals over the last 10 years, which are not described in the LCA databases. Furthermore, emission and energy factors for several of the by-products of the base metal production were lacking. This report aims in updating the life-cycle inventories associated with the production of the base metals (Zn, Cu, Al, Mo) and in defining the emission and energy allocations for the minor metals (Cd, In, Ge, Se, Te and Ga) used in photovoltaics.

  1. The social costs of solar energy: A study of photovoltaic energy systems

    Science.gov (United States)

    Neff, T. L.

    An extensive analysis of the social costs of photovoltaic energy systems shows that there are potentially significant hazards associated with the manufacture and use of such technologies as large-crystal silicon, cadmium sulfide, and gallium arsenide solar cell arrays. The categories of applications considered were (1) decentralized residential installations, (2) decentralized neighborhood, commercial or industrial installations, and (3) central station plants. Summary and conclusion statements are presented for occupational health, public health, environmental impacts, labor, materials and energy impacts, and implications for technological development. It is thought in overview that there are reasons for optimism about the ability of photovoltaics to improve the balance of social costs and benefits in the energy sector.

  2. Photovoltaic Devices from Multi-Armed CdS Nanorods and Conjugated Polyme, Composites

    Institute of Scientific and Technical Information of China (English)

    LIU Yan-Shan; WANG Li; QIN Dong-Huan; CAO Yong

    2006-01-01

    We demonstrate the preparation of composite photovoltaic devices by using the blends of multi-armed CdS nanorods with conjugated polymer, poly[2-methoxy-5-(2'-ethylhexyloxy)-l,4-phenylenevinylene] (MEH-PPV). Multi-armed CdS nanorods are prepared by thermolysing single precursor cadmium ethylxanthate [Cd(exan)2] in pure hexadecylamine solution under ambient conditions. The photoluminescence of MEH-PPV can be ef fectively quenched in the composites at high CdS nanocrystal (nc-CdS)/MEH-PPV ratios. Post-treatment of the multi-armed CdS nanorods by refluxing in pyridine significantly increases the performance of the composite photovoltaic devices. Power conversion efficiency is obtained to be 0.17% under AM 1.5 illumination for this composite device.

  3. Preparation of bismuth telluride thin film by electrochemical atomic layer epitaxy(ECALE)

    Institute of Scientific and Technical Information of China (English)

    ZHU Wen; YANG Junyou; GAO Xianhui; HOU Jie; BAO Siqian; FAN Xian

    2007-01-01

    Thin-layer electrochemical studies of the underpotential deposition(UPD)of Bi and Te on cold rolled silver substrate have been performed.The voltammetric analysis of underpotential shift demonstrates that the initial Te UPD on Bi-covered Ag and Bi UPD on Te-covered Ag fitted UPD dynamics mechanism.A thin film of bismuth telluride was formed by alternately depositing Te and Bi via an automated flow deposition system.X-ray diffraction indicated the deposits of Bi2Te3.Energy Dispersive X-ray Detector quantitative analysis gave a 2:3 stoichiornetric ratio of Bi to Te,which was consistent with X-ray Diffraction results.Electron probe microanalysis of the deposits showed a network structure that results from the surface defects of the cold rolled Ag substrate and the lattice mismatch between substrate and deposit.

  4. Study of transport properties co - evaporated lead telluride (PbTe) thin films

    Energy Technology Data Exchange (ETDEWEB)

    Khairnar, U.P.; Bhavsar, G.P. [Thin film laboratory, Physics Department Pratap College, Amalner (India); Pawar, P.H. [Department of Electronics, Jai-Hind College, Dhule (India)

    2002-07-01

    Thin films of lead telluride (PbTe) of thicknesses ranging from 1000 A to 2500 A have been prepared by co-evaporation (three temperature) technique, onto precleaned amorphous glass substrates at various temperatures. The deposited samples were annealed and annealed samples were used for characterization. Resistivity of these samples was measured by four-probe technique as a function of thickness and temperature. Activation energy for charge transport have been evaluated and found in the range of 0.09 to 0.106 eV. Thermoelectric power has been measured and found to be positive indicating that the samples are p-type semiconducting material. Mobility variation with temperature has been estimated (evaluated) and correlated with scattering mechanism in the entire range of temperature studied. The X-ray diffraction analysis confirmed that films are polycrystalline having cubic structure cell and lattice parameters are reported. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

  5. Evaluation of DAST and zinc telluride nonlinear crystals for efficient terahertz generation

    International Nuclear Information System (INIS)

    Terahertz (THz) signal is generated from 4-N, N-dimethylamino-4’-N’-methyl-stilbazolium tosylate (i.e. DAST Crystal) and Zinc telluride (ZnTe) nonlinear crystals by employing 140 fs laser pulses at 800 nm with 80 MHz repetition rate. The semi insulating gallium arsenide photoconductive stripline antennas (gap =5 µm, length = 20 µm) is used as a Terahertz detector. The detected temporal profile of Terahertz radiation generated from DAST crystal is high as compared to ZnTe crystal in terms of amplitude. THz effective bandwidths of these crystals are extended up to 1.1 THz range. The potential of THz generation of DAST and ZnTe crystals are evaluated with respect to incident laser power

  6. Synthesis of the titanium phosphide telluride Ti 2PTe 2: A thermochemical approach

    Science.gov (United States)

    Philipp, Frauke; Schmidt, Peer; Milke, Edgar; Binnewies, Michael; Hoffmann, Stefan

    2008-04-01

    The phosphide telluride Ti 2PTe 2 can be synthesised from the elements or from oxides in a thermite type reaction. Both ways have been optimised by consideration of the thermodynamic behaviour of the compound. Hence, the investigation of phase equilibria in the ternary system Ti/P/Te and of the thermal decomposition of Ti 2PTe 2 was necessary. This investigation was performed by using different experimental approaches as total pressure measurements, thermal analysis and mass spectrometry. The results were supported and further analysed by thermodynamic modelling of the ternary system. It was shown that Ti 2PTe 2(s) decomposes to Ti 2P (s) and Te 2(g) in six consecutive steps. The growth of single crystals of Ti 2PTe 2 is thermodynamically described as a chemical vapour transport with TiCl 4(g) acting as the transport agent.

  7. Simple routes to synthesis and characterization of nanosized tin telluride compounds

    Energy Technology Data Exchange (ETDEWEB)

    Salavati-Niasari, Masoud, E-mail: salavati@kashanu.ac.ir [Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P.O. Box. 87317-51167 (Iran, Islamic Republic of); Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P.O. Box. 87317-51167 (Iran, Islamic Republic of); Bazarganipour, Mehdi [Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P.O. Box. 87317-51167 (Iran, Islamic Republic of); Davar, Fatemeh [Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P.O. Box. 87317-51167 (Iran, Islamic Republic of); Fazl, Alireza Amini [Institute for Colorants, Paint and Coatings (ICPC), Tehran, P.O. Box. 16765/654 (Iran, Islamic Republic of)

    2010-11-15

    Nanosized tin telluride compounds were prepared by chemical reduction process and hydrothermal methods. The nanosized SnTe compounds were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The SnTe nanoalloy prepared by chemical reduction process presented quasi-spherical morphology with aggregation. The sizes of particle were 40-50 nm. The powder prepared by hydrothermal process was nearly nanospheres, and the particle sizes were 30-40 nm with narrow distribution. The effect of capping agent, reductant sort, and reaction temperature on the morphology, the particle sizes and the phase of SnTe alloys have been investigated. Experimental results indicated that N{sub 2}H{sub 4}.H{sub 2}O plays a crucial role in the formation of nanosized rode-like SnTe compounds.

  8. Nucleation and growth of noble metals on transition-metal di-tellurides

    Science.gov (United States)

    Hla, S. W.; Marinković, V.; Prodan, A.

    1997-04-01

    Transition-metal di-tellurides (α- and β-MoTe 2 and WTe 2) were used as substrates for nucleation and growth studies of noble metals. They represent a group of chemically closely related compounds with different surface topographies. Nucleation and growth of Ag and Au at room temperature were studied by means of UHV-STM, AFM and TEM. The results revealed that the growth and orientation of these metals are influenced by the topography of the substrate surfaces. Contrary to the growth on atomically flat α-MoTe 2, there is an enhanced diffusion and nucleation along the periodic surface troughs on β-MoTe 2 and WTe 2. The topography of their (001) surfaces is responsible for the orientation of metal (112) planes being parallel to the substrate surface.)

  9. Nanoscale arrays of antimony telluride single crystals by selective chemical vapor deposition

    Science.gov (United States)

    Huang, Ruomeng; Benjamin, Sophie L.; Gurnani, Chitra; Wang, Yudong; Hector, Andrew L.; Levason, William; Reid, Gillian; De Groot, C. H. (Kees)

    2016-01-01

    Arrays of individual single nanocrystals of Sb2Te3 have been formed using selective chemical vapor deposition (CVD) from a single source precursor. Crystals are self-assembled reproducibly in confined spaces of 100 nm diameter with pitch down to 500 nm. The distribution of crystallite sizes across the arrays is very narrow (standard deviation of 15%) and is affected by both the hole diameter and the array pitch. The preferred growth of the crystals in the orientation along the diagonal of the square holes strongly indicates that the diffusion of adatoms results in a near thermodynamic equilibrium growth mechanism of the nuclei. A clear relationship between electrical resistivity and selectivity is established across a range of metal selenides and tellurides, showing that conductive materials result in more selective growth and suggesting that electron donation is of critical importance for selective deposition. PMID:27283116

  10. Epithermal Gold-Silver Deposits in Western Java, Indonesia: Gold-Silver Selenide-Telluride Mineralization

    Directory of Open Access Journals (Sweden)

    Euis Tintin Yuningsih

    2014-09-01

    Full Text Available DOI: 10.17014/ijog.v1i2.180The gold-silver ores of western Java reflect a major metallogenic event during the Miocene-Pliocene and Pliocene ages. Mineralogically, the deposits can be divided into two types i.e. Se- and Te-type deposits with some different characteristic features. The objective of the present research is to summarize the mineralogical and geochemical characteristics of Se- and Te-type epithermal mineralization in western Java. Ore and alteration mineral assemblage, fluid inclusions, and radiogenic isotope studies were undertaken in some deposits in western Java combined with literature studies from previous authors. Ore mineralogy of some deposits from western Java such as Pongkor, Cibaliung, Cikidang, Cisungsang, Cirotan, Arinem, and Cineam shows slightly different characteristics as those are divided into Se- and Te-types deposits. The ore mineralogy of the westernmost of west Java region such as Pongkor, Cibaliung, Cikidang, Cisungsang, and Cirotan is characterized by the dominance of silver-arsenic-antimony sulfosalt with silver selenides and rarely tellurides over the argentite, while to the eastern part of West Java such as Arinem and Cineam deposits are dominated by silver-gold tellurides. The average formation temperatures measured from fluid inclusions of quartz associated with ore are in the range of 170 – 220°C with average salinity of less than 1 wt% NaClequiv for Se-type and 190 – 270°C with average salinity of ~2 wt% NaClequiv for Te-type.

  11. Photovoltaic array mounting apparatus, systems, and methods

    Science.gov (United States)

    West, Jack Raymond; Atchley, Brian; Hudson, Tyrus Hawkes; Johansen, Emil

    2015-04-14

    A photovoltaic array, including: (a) supports laid out on a surface in rows and columns; (b) photovoltaic modules positioned on top of the supports; and (c) fasteners connecting the photovoltaic modules to the supports, wherein the supports have an upper pedestal surface and a lower pedestal surface such that the photovoltaic modules are positioned at a non-horizontal angle when edges of the photovoltaic modules are positioned on top of the upper and lower pedestal surfaces, and wherein a portion of the fasteners rotate to lock the photovoltaic modules onto the supports.

  12. Photovoltaic array mounting apparatus, systems, and methods

    Energy Technology Data Exchange (ETDEWEB)

    West, Jack Raymond; Atchley, Brian; Hudson, Tyrus Hawkes; Johansen, Emil

    2016-01-05

    A photovoltaic array, including: (a) supports laid out on a surface in rows and columns; (b) photovoltaic modules positioned on top of the supports; and (c) fasteners connecting the photovoltaic modules to the supports, wherein the supports have an upper pedestal surface and a lower pedestal surface such that the photovoltaic modules are positioned at a non-horizontal angle when edges of the photovoltaic modules are positioned on top of the upper and lower pedestal surfaces, and wherein a portion of the fasteners rotate to lock the photovoltaic modules onto the supports.

  13. Immunocytotoxicity, cytogenotoxicity and genotoxicity of cadmium-based quantum dots in the marine mussel Mytilus galloprovincialis.

    Science.gov (United States)

    Rocha, Thiago Lopes; Gomes, Tânia; Cardoso, Cátia; Letendre, Julie; Pinheiro, José Paulo; Sousa, Vânia Serrão; Teixeira, Margarida Ribau; Bebianno, Maria João

    2014-10-01

    There is an increased use of Quantum Dot (QDs) in biological and biomedical applications, but little is known about their marine ecotoxicology. So, the aim of this study was to investigate the possible immunocytotoxic, cytogenotoxic and genotoxic effects of cadmium telluride QDs (CdTe QDs) on the marine mussel Mytilus galloprovincialis. Mussels were exposed to 10 μg L(-1) of CdTe QDs or to soluble Cd [Cd(NO3)2] for 14 days and Cd accumulation, immunocytotoxicity [hemocyte density, cell viability, lysosomal membrane stability (LMS), differential cell counts (DCC)], cytogenotoxicity (micronucleus test and nuclear abnormalities assay) and genotoxicity (comet assay) were analyzed. Results show that in vivo exposure to QDs, Cd is accumulated in mussel soft tissues and hemolymph and induce immunotoxic effects mediated by a decrease in LMS, changes in DCC, as well as genotoxicity (DNA damage). However, QDs do not induce significant changes in hemocytes density, cell viability and cytogenetic parameters in opposition to Cd(2+). Soluble Cd is the most cytotoxic and cytogenotoxic form on Mytilus hemocytes due to a higher accumulation of Cd in tissues. Results indicate that immunotoxicity and genotoxicity of CdTe QDs and Cd(2+) are mediated by different modes of action and show that Mytilus hemocytes are important targets for in vivo QDs toxicity.

  14. Nanocrystal grain growth and device architectures for high-efficiency CdTe ink-based photovoltaics.

    Science.gov (United States)

    Crisp, Ryan W; Panthani, Matthew G; Rance, William L; Duenow, Joel N; Parilla, Philip A; Callahan, Rebecca; Dabney, Matthew S; Berry, Joseph J; Talapin, Dmitri V; Luther, Joseph M

    2014-09-23

    We study the use of cadmium telluride (CdTe) nanocrystal colloids as a solution-processable "ink" for large-grain CdTe absorber layers in solar cells. The resulting grain structure and solar cell performance depend on the initial nanocrystal size, shape, and crystal structure. We find that inks of predominantly wurtzite tetrapod-shaped nanocrystals with arms ∼5.6 nm in diameter exhibit better device performance compared to inks composed of smaller tetrapods, irregular faceted nanocrystals, or spherical zincblende nanocrystals despite the fact that the final sintered film has a zincblende crystal structure. Five different working device architectures were investigated. The indium tin oxide (ITO)/CdTe/zinc oxide structure leads to our best performing device architecture (with efficiency >11%) compared to others including two structures with a cadmium sulfide (CdS) n-type layer typically used in high efficiency sublimation-grown CdTe solar cells. Moreover, devices without CdS have improved response at short wavelengths.

  15. Nanocrystal grain growth and device architectures for high-efficiency CdTe ink-based photovoltaics.

    Science.gov (United States)

    Crisp, Ryan W; Panthani, Matthew G; Rance, William L; Duenow, Joel N; Parilla, Philip A; Callahan, Rebecca; Dabney, Matthew S; Berry, Joseph J; Talapin, Dmitri V; Luther, Joseph M

    2014-09-23

    We study the use of cadmium telluride (CdTe) nanocrystal colloids as a solution-processable "ink" for large-grain CdTe absorber layers in solar cells. The resulting grain structure and solar cell performance depend on the initial nanocrystal size, shape, and crystal structure. We find that inks of predominantly wurtzite tetrapod-shaped nanocrystals with arms ∼5.6 nm in diameter exhibit better device performance compared to inks composed of smaller tetrapods, irregular faceted nanocrystals, or spherical zincblende nanocrystals despite the fact that the final sintered film has a zincblende crystal structure. Five different working device architectures were investigated. The indium tin oxide (ITO)/CdTe/zinc oxide structure leads to our best performing device architecture (with efficiency >11%) compared to others including two structures with a cadmium sulfide (CdS) n-type layer typically used in high efficiency sublimation-grown CdTe solar cells. Moreover, devices without CdS have improved response at short wavelengths. PMID:25133302

  16. Singlet exciton fission photovoltaics.

    Science.gov (United States)

    Lee, Jiye; Jadhav, Priya; Reusswig, Philip D; Yost, Shane R; Thompson, Nicholas J; Congreve, Daniel N; Hontz, Eric; Van Voorhis, Troy; Baldo, Marc A

    2013-06-18

    Singlet exciton fission, a process that generates two excitons from a single photon, is perhaps the most efficient of the various multiexciton-generation processes studied to date, offering the potential to increase the efficiency of solar devices. But its unique characteristic, splitting a photogenerated singlet exciton into two dark triplet states, means that the empty absorption region between the singlet and triplet excitons must be filled by adding another material that captures low-energy photons. This has required the development of specialized device architectures. In this Account, we review work to develop devices that harness the theoretical benefits of singlet exciton fission. First, we discuss singlet fission in the archetypal material, pentacene. Pentacene-based photovoltaic devices typically show high external and internal quantum efficiencies. They have enabled researchers to characterize fission, including yield and the impact of competing loss processes, within functional devices. We review in situ probes of singlet fission that modulate the photocurrent using a magnetic field. We also summarize studies of the dissociation of triplet excitons into charge at the pentacene-buckyball (C60) donor-acceptor interface. Multiple independent measurements confirm that pentacene triplet excitons can dissociate at the C60 interface despite their relatively low energy. Because triplet excitons produced by singlet fission each have no more than half the energy of the original photoexcitation, they limit the potential open circuit voltage within a solar cell. Thus, if singlet fission is to increase the overall efficiency of a solar cell and not just double the photocurrent at the cost of halving the voltage, it is necessary to also harvest photons in the absorption gap between the singlet and triplet energies of the singlet fission material. We review two device architectures that attempt this using long-wavelength materials: a three-layer structure that uses

  17. Improvement of cadmium phytoremediation after soil inoculation with a cadmium-resistant Micrococcus sp.

    Science.gov (United States)

    Sangthong, Chirawee; Setkit, Kunchaya; Prapagdee, Benjaphorn

    2016-01-01

    Cadmium-resistant Micrococcus sp. TISTR2221, a plant growth-promoting bacterium, has stimulatory effects on the root lengths of Zea mays L. seedlings under toxic cadmium conditions compared to uninoculated seedlings. The performance of Micrococcus sp. TISTR2221 on promoting growth and cadmium accumulation in Z. mays L. was investigated in a pot experiment. The results indicated that Micrococcus sp. TISTR2221significantly promoted the root length, shoot length, and dry biomass of Z. mays L. transplanted in both uncontaminated and cadmium-contaminated soils. Micrococcus sp. TISTR2221 significantly increased cadmium accumulation in the roots and shoots of Z. mays L. compared to uninoculated plants. At the beginning of the planting period, cadmium accumulated mainly in the shoots. With a prolonged duration of cultivation, cadmium content increased in the roots. As expected, little cadmium was found in maize grains. Soil cadmium was significantly reduced with time, and the highest percentage of cadmium removal was found in the bacterial-inoculated Z. mays L. after transplantation for 6 weeks. We conclude that Micrococcus sp. TISTR2221 is a potent bioaugmenting agent, facilitating cadmium phytoextraction in Z. mays L.

  18. Nanowire Photovoltaic Devices

    Science.gov (United States)

    Forbes, David

    2015-01-01

    Firefly Technologies, in collaboration with the Rochester Institute of Technology and the University of Wisconsin-Madison, developed synthesis methods for highly strained nanowires. Two synthesis routes resulted in successful nanowire epitaxy: direct nucleation and growth on the substrate and a novel selective-epitaxy route based on nanolithography using diblock copolymers. The indium-arsenide (InAs) nanowires are implemented in situ within the epitaxy environment-a significant innovation relative to conventional semiconductor nanowire generation using ex situ gold nanoparticles. The introduction of these nanoscale features may enable an intermediate band solar cell while simultaneously increasing the effective absorption volume that can otherwise limit short-circuit current generated by thin quantized layers. The use of nanowires for photovoltaics decouples the absorption process from the current extraction process by virtue of the high aspect ratio. While no functional solar cells resulted from this effort, considerable fundamental understanding of the nanowire epitaxy kinetics and nanopatterning process was developed. This approach could, in principle, be an enabling technology for heterointegration of dissimilar materials. The technology also is applicable to virtual substrates. Incorporating nanowires onto a recrystallized germanium/metal foil substrate would potentially solve the problem of grain boundary shunting of generated carriers by restricting the cross-sectional area of the nanowire (tens of nanometers in diameter) to sizes smaller than the recrystallized grains (0.5 to 1 micron(exp 2).

  19. All-Oxide Photovoltaics.

    Science.gov (United States)

    Rühle, Sven; Anderson, Assaf Y; Barad, Hannah-Noa; Kupfer, Benjamin; Bouhadana, Yaniv; Rosh-Hodesh, Eli; Zaban, Arie

    2012-12-20

    Recently, a new field in photovoltaics (PV) has emerged, focusing on solar cells that are entirely based on metal oxide semiconductors. The all-oxide PV approach is very attractive due to the chemical stability, nontoxicity, and abundance of many metal oxides that potentially allow manufacturing under ambient conditions. Already today, metal oxides (MOs) are widely used as components in PV cells such as transparent conducting front electrodes or electron-transport layers, while only very few MOs have been used as light absorbers. In this Perspective, we review recent developments of all-oxide PV systems, which until today were mostly based on Cu2O as an absorber. Furthermore, ferroelectric BiFeO3-based PV systems are discussed, which have recently attracted considerable attention. The performance of all-oxide PV cells is discussed in terms of general PV principles, and directions for progress are proposed, pointing toward the development of novel metal oxide semiconductors using combinatorial methods. PMID:26291107

  20. Photovoltaic Incentive Design Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Hoff, T. E.

    2006-12-01

    Investments in customer-owned grid-connected photovoltaic (PV) energy systems are growing at a steady pace. This is due, in part, to the availability of attractive economic incentives offered by public state agencies and utilities. In the United States, these incentives have largely been upfront lump payments tied to the system capacity rating. While capacity-based ''buydowns'' have stimulated the domestic PV market, they have been criticized for subsidizing systems with potentially poor energy performance. As a result, the industry has been forced to consider alternative incentive structures, particularly ones that pay based on long-term measured performance. The industry, however, lacks consensus in the debate over the tradeoffs between upfront incentive payments versus longer-term payments for energy delivery. This handbook is designed for agencies and utilities that offer or intend to offer incentive programs for customer-owned PV systems. Its purpose is to help select, design, and implement incentive programs that best meet programmatic goals. The handbook begins with a discussion of the various available incentive structures and then provides qualitative and quantitative tools necessary to design the most appropriate incentive structure. It concludes with program administration considerations.

  1. Cadmium Modulates Biofilm Formation by Staphylococcus epidermidis

    NARCIS (Netherlands)

    Wu, Xueqing; Santos, Regiane R.; Fink-Gremmels, Johanna

    2015-01-01

    The aim of the study was to evaluate the effect of cadmium exposure on Staphylococcus epidermidis (ATCC 35984) biofilm formation. Bacteria were cultured in the absence or presence of different concentrations (0-50 mu M) of cadmium. Biofilm formation and bacterial viability were assessed. Quantitativ

  2. Survey of Facilities for Testing Photovoltaics

    Science.gov (United States)

    Weaver, R. W.

    1982-01-01

    42-page report describes facilities capable of testing complete photovoltaic systems, subsystems, or components. Compilation includes facilities and capabilities of five field centers of national photovoltaics program, two state-operated agencies, and five private testing laboratories.

  3. Mounting support for a photovoltaic module

    Science.gov (United States)

    Brandt, Gregory Michael; Barsun, Stephan K.; Coleman, Nathaniel T.; Zhou, Yin

    2013-03-26

    A mounting support for a photovoltaic module is described. The mounting support includes a foundation having an integrated wire-way ledge portion. A photovoltaic module support mechanism is coupled with the foundation.

  4. ULTRA BARRIER TOPSHEET (UBT) FOR FLEXIBLE PHOTOVOLTAICS

    Energy Technology Data Exchange (ETDEWEB)

    DeScioli, Derek

    2013-06-01

    This slide-show presents 3M photovoltaic-related products, particularly flexible components. Emphasis is on the 3M Ultra Barrier Solar Films. Topics covered include reliability and qualification testing and flexible photovoltaic encapsulation costs.

  5. Photovoltaic product directory and buyers guide

    Energy Technology Data Exchange (ETDEWEB)

    Watts, R.L.; Smith, S.A.; Mazzucchi, R.P.

    1981-06-01

    Basic information on photovoltaic conversion technology is provided for those unfamiliar with the field. Various types of photovoltaic products and systems currently available off-the-shelf are described. These include products without batteries, battery chargers, power packages, home electric systems, and partial systems. Procedures are given for designing a photovoltaic system from scratch. A few custom photovoltaic systems are described, and a list is compiled of photovoltaic firms which can provide custom systems. Guidance is offered for deciding whether or not to use photovoltaic products. A variety of installations are described and their performance is appraised by the owners. Information is given on various financial incentives available from state and federal governments. Sources of additional information on photovoltaics are listed. A matrix is provided indicating the sources of various types of photovoltaic products. The addresses of suppliers are listed. (LEW)

  6. Optimizing Grid Patterns on Photovoltaic Cells

    Science.gov (United States)

    Burger, D. R.

    1984-01-01

    CELCAL computer program helps in optimizing grid patterns for different photovoltaic cell geometries and metalization processes. Five different powerloss phenomena associated with front-surface metal grid pattern on photovoltaic cells.

  7. Enhanced diode performance in cadmium telluride–silicon nanowire heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Akgul, Funda Aksoy, E-mail: fundaaksoy01@gmail.com [Department of Physics, Nigde University, 51240 Nigde (Turkey); Center for Solar Energy Research and Applications, Middle East Technical University, 06800 Ankara (Turkey); Akgul, Guvenc, E-mail: guvencakgul@gmail.com [Bor Vocational School, Nigde University, 51700 Nigde (Turkey); Center for Solar Energy Research and Applications, Middle East Technical University, 06800 Ankara (Turkey); Gullu, Hasan Huseyin [Department of Physics, Middle East Technical University, 06800 Ankara (Turkey); Center for Solar Energy Research and Applications, Middle East Technical University, 06800 Ankara (Turkey); Unalan, Husnu Emrah [Department of Metallurgical and Materials Engineering, Middle East Technical University, 06800 Ankara (Turkey); Center for Solar Energy Research and Applications, Middle East Technical University, 06800 Ankara (Turkey); Turan, Rasit [Department of Physics, Middle East Technical University, 06800 Ankara (Turkey); Center for Solar Energy Research and Applications, Middle East Technical University, 06800 Ankara (Turkey)

    2015-09-25

    Highlights: • Vertically well oriented Si nanowire arrays on Si wafer were synthesized. • Semiconductor CdTe thin film/Si nanowire devices were successfully fabricated. • Optoelectronic properties of the fabricated devices were investigated. • Enhanced electrical and diode properties for the devices were observed. • The devices exhibited strong photosensitivity in near infrared region. - Abstract: We report on the structural and optoelectronic characteristics and photodetection properties of cadmium telluride (CdTe) thin film/silicon (Si) nanowire heterojunction diodes. A simple and cost-effective metal-assisted etching (MAE) method is applied to fabricate vertically oriented Si nanowires on n-type single crystalline Si wafer. Following the nanowire synthesis, CdTe thin films are directly deposited onto the Si nanowire arrays through RF magnetron sputtering. A comparative study of X-ray diffraction (XRD) and Raman spectroscopy shows the improved crystallinity of the CdTe thin films deposited onto the Si nanowires. The fabricated nanowire based heterojunction devices exhibit remarkable diode characteristics, enhanced optoelectronic properties and photosensitivity in comparison to the planar reference device. The electrical measurements revealed that the diodes have a well-defined rectifying behavior with a superior rectification ratio of 10{sup 5} at ±5 V and a relatively small ideality factor of n = 1.9 with lower reverse leakage current and series resistance at room temperature in dark condition. Moreover, an open circuit voltage of 120 mV is also observed under illumination. Based on spectral photoresponsivity measurements, the nanowire based device exhibits a distinct responsivity (0.35–0.5 A W{sup −1}) and high detectivity (6 × 10{sup 12}−9 × 10{sup 12} cm Hz{sup 1/2} W{sup −1}) in near-infrared wavelength region. The enhanced device performance and photosensitivity is believed to be due to three-dimensional nature of the interface between

  8. Enhanced diode performance in cadmium telluride–silicon nanowire heterostructures

    International Nuclear Information System (INIS)

    Highlights: • Vertically well oriented Si nanowire arrays on Si wafer were synthesized. • Semiconductor CdTe thin film/Si nanowire devices were successfully fabricated. • Optoelectronic properties of the fabricated devices were investigated. • Enhanced electrical and diode properties for the devices were observed. • The devices exhibited strong photosensitivity in near infrared region. - Abstract: We report on the structural and optoelectronic characteristics and photodetection properties of cadmium telluride (CdTe) thin film/silicon (Si) nanowire heterojunction diodes. A simple and cost-effective metal-assisted etching (MAE) method is applied to fabricate vertically oriented Si nanowires on n-type single crystalline Si wafer. Following the nanowire synthesis, CdTe thin films are directly deposited onto the Si nanowire arrays through RF magnetron sputtering. A comparative study of X-ray diffraction (XRD) and Raman spectroscopy shows the improved crystallinity of the CdTe thin films deposited onto the Si nanowires. The fabricated nanowire based heterojunction devices exhibit remarkable diode characteristics, enhanced optoelectronic properties and photosensitivity in comparison to the planar reference device. The electrical measurements revealed that the diodes have a well-defined rectifying behavior with a superior rectification ratio of 105 at ±5 V and a relatively small ideality factor of n = 1.9 with lower reverse leakage current and series resistance at room temperature in dark condition. Moreover, an open circuit voltage of 120 mV is also observed under illumination. Based on spectral photoresponsivity measurements, the nanowire based device exhibits a distinct responsivity (0.35–0.5 A W−1) and high detectivity (6 × 1012−9 × 1012 cm Hz1/2 W−1) in near-infrared wavelength region. The enhanced device performance and photosensitivity is believed to be due to three-dimensional nature of the interface between the CdTe thin film and the Si

  9. Cadmium stress in wheat seedlings: growth, cadmium accumulation and photosynthesis

    DEFF Research Database (Denmark)

    Ci, Dunwei; Jiang, Dong; Wollenweber, Bernd;

    2010-01-01

    Seedlings of wheat (Triticum aestivum L.) cultivars Jing 411, Jinmai 30 and Yangmai 10 were exposed to 0, 10, 20, 30, 40 or 50 μM of CdCl2 in a solution culture experiment. The effects of cadmium (Cd) stress on wheat growth, leaf photon energy conversion, gas exchange, and Cd accumulation in wheat...... parameters were generally depressed by Cd stress, especially under the high Cd concentrations. Cd concentration and accumulation in both shoots and roots increased with increasing external Cd concentrations. Relationships between corrected parameters of growth, photosynthesis and fluorescence and corrected...

  10. Geology of the florencia gold – telluride deposit (camagüey, cuba) and some metallurgical considerations

    OpenAIRE

    López K Jesús M.; Moreira Jesús; Gandarillas José

    2011-01-01

    This paper describes the results from a study of the Florencia gold-telluride deposit in Central Cuba, including mineralogical, petrographical, microprobe and chemical analysis. Valuable information is provided for the exploration, mining and processing of gold ores from other nearby deposits with similar characteristics. Results highlight changes in the mineralogical composition of the ores between the north and south sectors of the deposit, as reflected in metallurgical concentrates after b...

  11. Process Development for Nanostructured Photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Elam, Jeffrey W.

    2015-01-01

    Photovoltaic manufacturing is an emerging industry that promises a carbon-free, nearly limitless source of energy for our nation. However, the high-temperature manufacturing processes used for conventional silicon-based photovoltaics are extremely energy-intensive and expensive. This high cost imposes a critical barrier to the widespread implementation of photovoltaic technology. Argonne National Laboratory and its partners recently invented new methods for manufacturing nanostructured photovoltaic devices that allow dramatic savings in materials, process energy, and cost. These methods are based on atomic layer deposition, a thin film synthesis technique that has been commercialized for the mass production of semiconductor microelectronics. The goal of this project was to develop these low-cost fabrication methods for the high efficiency production of nanostructured photovoltaics, and to demonstrate these methods in solar cell manufacturing. We achieved this goal in two ways: 1) we demonstrated the benefits of these coatings in the laboratory by scaling-up the fabrication of low-cost dye sensitized solar cells; 2) we used our coating technology to reduce the manufacturing cost of solar cells under development by our industrial partners.

  12. Immunoassay for Cadmium Detection and Quantification

    Institute of Scientific and Technical Information of China (English)

    GONG-LIANG LIU; JU-FANG WANG; ZHI-YONG LI; SHI-ZHONG LIANG; XIAO-NING WANG

    2009-01-01

    Objective To detect cadmium in environmental and food samples by graphite furnace atomic absorption spectroscopy (GFAAS) and inductively coupled plasma atomic emission spectroscopy (ICPAES). Methods An indirect competitive enzyme-linked immunosorbent assay (IC-ELISA) was developed based on a cadmium-specific monoclonal antibody.IC-ELISA for cadmium in environmental and food samples was evaluated. Results IC-ELISA showed an IC50 of 45.6 μg/L with a detection limit of 1.95 μg/L for cadmium,and showed a mean recovery ranging 97.67%-107.08%.The coefficient of variations for intra- and iuterassay was 3.41%-6.61% and 4.70%-9.21%,respectively.The correlation coefficient between IC-ELISA and GFAAS was 0.998. Conclusion IC-ELISA can detect and quantify cadmium residue in environmental or food samples.

  13. Dynamics of Incoherent Photovoltaic Spatial Solitons

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yi-Qi; LU Ke-Qing; ZHANG Mei-Zhi; LI Ke-Hao; LIU Shuang; ZHANG Yan-Peng

    2009-01-01

    Propagation properties of bright and dark incoherent beams are numerically studied in photovoltaic-photorefractive crystal by using coherent density approach for the first time.Numerical simulations not only exhibit that bright incoherent photovoltaic quasi-soliton,grey-like incoherent photovoltaic soliton,incoherent soliton doublet and triplet can be established under proper conditions,but also display that the spatial coherence properties of these incoherent beams can be significantly affected during propagation by the photovoltaic field.

  14. Grounds of two positions photovoltaic panels

    OpenAIRE

    Castán Fortuño, Fernando

    2008-01-01

    The objective of this Master Thesis is to find the optimum positioning for a two positions photovoltaic panel. Hence, it will be implemented a model in order to optimize the energy of the sun that the photovoltaic panel is receiving by its positioning. Likewise this project will include the comparison with other photovoltaic panel systems as the single position photovoltaics panels. Ultimately, it is also going to be designed a system array for the optimized model of two positions photovoltai...

  15. Cadmium mobility and accumulation in soils of the European Communities

    NARCIS (Netherlands)

    Fraters B; van Beurden AUCJ

    1993-01-01

    In this overview of the effects of cadmium pollution on agricultural soils in the European Community, both the cadmium loads on agricultural land and the soil sensitivity to cadmium accumulation have been estimated. Cadmium loads have been estimated separately for arable land and grassland. The ef

  16. Enhanced thermoelectric properties of phase-separating bismuth selenium telluride thin films via a two-step method

    International Nuclear Information System (INIS)

    A two-step method that combines homogeneous electron beam (EB) irradiation and thermal annealing has been developed to enhance the thermoelectric properties of nanocrystalline bismuth selenium telluride thin films. The thin films, prepared using a flash evaporation method, were treated with EB irradiation in a N2 atmosphere at room temperature and an acceleration voltage of 0.17 MeV. Thermal annealing was performed under Ar/H2 (5%) at 300 °C for 60 min. X-ray diffraction was used to determine that compositional phase separation between bismuth telluride and bismuth selenium telluride developed in the thin films exposed to higher EB doses and thermal annealing. We propose that the phase separation was induced by fluctuations in the distribution of selenium atoms after EB irradiation, followed by the migration of selenium atoms to more stable sites during thermal annealing. As a result, thin film crystallinity improved and mobility was significantly enhanced. This indicates that the phase separation resulting from the two-step method enhanced, rather than disturbed, the electron transport. Both the electrical conductivity and the Seebeck coefficient were improved following the two-step method. Consequently, the power factor of thin films that underwent the two-step method was enhanced to 20 times (from 0.96 to 21.0 μW/(cm K2) that of the thin films treated with EB irradiation alone

  17. Enhanced thermoelectric properties of phase-separating bismuth selenium telluride thin films via a two-step method

    Energy Technology Data Exchange (ETDEWEB)

    Takashiri, Masayuki, E-mail: takashiri@tokai-u.jp; Kurita, Kensuke [Department of Materials Science, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); Hagino, Harutoshi; Miyazaki, Koji [Department of Mechanical and Control Engineering, Kyushu Institute of Technology, 1-1 Sensui, Tobata-ku, Kitakyushu 804-8550 (Japan); Tanaka, Saburo [Department of Mechanical Engineering, College of Engineering, Nihon University, 1 Nakagawara, Tokusada, Tamuramachi, Koriyama, Fukushima 963-8642 (Japan)

    2015-08-14

    A two-step method that combines homogeneous electron beam (EB) irradiation and thermal annealing has been developed to enhance the thermoelectric properties of nanocrystalline bismuth selenium telluride thin films. The thin films, prepared using a flash evaporation method, were treated with EB irradiation in a N{sub 2} atmosphere at room temperature and an acceleration voltage of 0.17 MeV. Thermal annealing was performed under Ar/H{sub 2} (5%) at 300 °C for 60 min. X-ray diffraction was used to determine that compositional phase separation between bismuth telluride and bismuth selenium telluride developed in the thin films exposed to higher EB doses and thermal annealing. We propose that the phase separation was induced by fluctuations in the distribution of selenium atoms after EB irradiation, followed by the migration of selenium atoms to more stable sites during thermal annealing. As a result, thin film crystallinity improved and mobility was significantly enhanced. This indicates that the phase separation resulting from the two-step method enhanced, rather than disturbed, the electron transport. Both the electrical conductivity and the Seebeck coefficient were improved following the two-step method. Consequently, the power factor of thin films that underwent the two-step method was enhanced to 20 times (from 0.96 to 21.0 μW/(cm K{sup 2}) that of the thin films treated with EB irradiation alone.

  18. Effects of chemical intermixing on electrical and thermal contact conductances at metallized bismuth and antimony telluride interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Devender,; Mehta, Rutvik J.; Ramanath, Ganpati, E-mail: Ramanath@rpi.edu [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Lofgreen, Kelly; Mahajan, Ravi [Intel Corporation, Assembly Test and Technology Development, Chandler, Arizona 85226 (United States); Yamaguchi, Masashi [Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Borca-Tasciuc, Theodorian [Department of Mechanical Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

    2015-03-15

    Tailoring electrical and thermal contact conductivities (Σ{sub c} and Γ{sub c}) across metallized pnictogen chalcogenide interfaces is key for realizing efficient thermoelectric devices. The authors report that Cu, Ni, Ti, and Ta diffusion and interfacial telluride formation with n-Bi{sub 2}Te{sub 3} and p-Sb{sub 2}Te{sub 3} influence both Σ{sub c} and Γ{sub c}. Cu metallization yields the highest Γ{sub c} and the lowest Σ{sub c}, correlating with maximal metal diffusion and copper telluride formation. Ni diffuses less and yields the highest Σ{sub c} with Sb{sub 2}Te{sub 3} due to p-type nickel telluride formation, which diminishes Σ{sub c} improvement with n-Bi{sub 2}Te{sub 3} interfaces. Ta and Ti contacts yield the lowest properties similar to that in Ni-metallized structures. These correlations between interfacial diffusion and phase formation on electronic and thermal transport properties will be important for devising suitable metallization for thermoelectric devices.

  19. INCOHERENTLY COUPLED SCREENING-PHOTOVOLTAIC SOLITON FAMILIES IN BIASED PHOTOVOLTAIC PHOTOREFRACTIVE CRYSTALS

    Institute of Scientific and Technical Information of China (English)

    HOU CHUN-FENG; LI BIN; SUN XIU-DONG; JIANG YONG-YUAN; XU KE-BIN

    2001-01-01

    It is shown that the existence of incoherently coupled screening-photovoltaic soliton families is possible in biased photovoltaic photorefractive crystals under steady-state conditions. These screening-photovoltaic soliton families can be established provided the multiple incident beams have the same polarization and wavelength, and are mutually incoherent. Such soliton families reduce to screening-photovoltaic soliton pairs when they contain only two components. Relevant examples are presented where the photovoltaic photorefractive crystal is of the lithium niobate type.

  20. International photovoltaic products and manufacturers directory, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Shepperd, L.W. [ed.] [Florida Solar Energy Center, Cocoa, FL (United States)

    1995-11-01

    This international directory of more than 500 photovoltaic-related manufacturers is intended to guide potential users of photovoltaics to sources for systems and their components. Two indexes help the user to locate firms and materials. A glossary describes equipment and terminology commonly used in the photovoltaic industry.