WorldWideScience

Sample records for solar spectrum stability

  1. Environmental stability study of holographic solar spectrum splitting materials

    Science.gov (United States)

    Chrysler, Benjamin D.; Ayala Pelaez, Silvana; Wu, Yuechen; Vorndran, Shelby D.; Kostuk, Raymond K.

    2016-09-01

    In this study the impact of outdoor temperature variations and solar illumination exposure on spectral filter material and holographic optical elements is examined. Although holographic components have been shown to be useful for solar spectrum splitting designs, relatively little quantitative data exist to demonstrate the extent to which these materials can withstand outdoor conditions. As researchers seek to investigate practical spectrum splitting designs, the environmental stability of holographic materials should be considered as an important factor. In the experiment presented, two holographic materials, Covestro Bayfol HX photopolymer and dichromated gelatin, and 3M reflective polymer filter materials are exposed to outdoor conditions for a period of several months. The environmental effect on absorption, spectral and angular bandwidth, peak efficiency, and Bragg matching conditions for the holograms are examined. Spectral bandwidth and transmittance of the 3M reflective filter material are also monitored. Holographic gratings are recorded, measured, and mounted on glass substrates and then sealed with a glass cover plate. The test samples are then mounted on a photovoltaic panel to simulate realistic temperature conditions and placed at an outdoor test facility in Tucson, Arizona. A duplicate set of holograms and 3M filter material is stored as a control group and periodically compared over the test period.

  2. Spectrum stabilizer; Stabilisateur de spectres

    Energy Technology Data Exchange (ETDEWEB)

    Detourne, G. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires, Departement d' electronique generale, Service d' instrumentation nucleaire

    1967-05-01

    A spectrum stabilizer is a control mechanism which renders an analytical chain reliable. It can detect a drift in the amplification and in the base of the energy scale, and can modify the characteristics of this chain. The results of a theoretical study make it possible to calculate the width and the abscissae of the peaks of a stabilized spectrum as a function of the drifts. The SPECTROSTAB is a numerical stabilizer of a continuous type; it provides the artificial reference peak at low energies. Experimental results give the performances obtained on a reference peak provided by a semi-conductor detector, in the field of gamma spectroscopy. (author) [French] Un stabilisateur de spectres est un asservissement qui permet de rendre fidele une cha e d'analyse. Il detecte les derives du gain et de l'origine de l'echelle des energies et reagit sur les caracteristiques de cette cha e. Les resultats d'une etude theorique permettent le calcul des elargissements et des abscisses des pics d'un spectre stabilise, en fonction des derives. Le SPECTROSTAB est un stabilisateur numerique du genre continu; il fournit le pic de reference artificiel aux basses energies. Des resultats experimentaux donnent les performances obtenues sur un pic de reference fourni par un detecteur a semi-conducteur, dans le domaine de la spectrometrie gamma. (auteur)

  3. Adaptive, full-spectrum solar energy system

    Science.gov (United States)

    Muhs, Jeffrey D.; Earl, Dennis D.

    2003-08-05

    An adaptive full spectrum solar energy system having at least one hybrid solar concentrator, at least one hybrid luminaire, at least one hybrid photobioreactor, and a light distribution system operably connected to each hybrid solar concentrator, each hybrid luminaire, and each hybrid photobioreactor. A lighting control system operates each component.

  4. Solar spectrum conversion for photovoltaics using nanoparticles

    OpenAIRE

    Sark, W.G.J.H.M. van; Meijerink, A.; Schropp, R.E.I.

    2012-01-01

    The possibility to tune chemical and physical properties in nanosized materials has a strong impact on a variety of technologies, including photovoltaics. One of the prominent research areas of nanomaterials for photovoltaics involves spectral conversion. Conventional single-junction semiconductor solar cells only effectively convert photons of energy close to the semiconductor band gap (Eg) as a result of the mismatch between the incident solar spectrum and the spectral absorption properties...

  5. A synthetic method of solar spectrum based on LED

    Science.gov (United States)

    Wang, Ji-qiang; Su, Shi; Zhang, Guo-yu; Zhang, Jian

    2017-10-01

    A synthetic method of solar spectrum which based on the spectral characteristics of the solar spectrum and LED, and the principle of arbitrary spectral synthesis was studied by using 14 kinds of LED with different central wavelengths.The LED and solar spectrum data were selected by Origin Software firstly, then calculated the total number of LED for each center band by the transformation relation between brightness and illumination and Least Squares Curve Fit in Matlab.Finally, the spectrum curve of AM1.5 standard solar spectrum was obtained. The results met the technical indexes of the solar spectrum matching with ±20% and the solar constant with >0.5.

  6. Generation of solar spectrum by using LEDs

    Science.gov (United States)

    Lu, Pengzhi; Yang, Hua; Pei, Yanrong; Li, Jing; Xue, Bin; Wang, Junxi; Li, Jinmin

    2016-09-01

    Light emitting diode (LED) has been recognized as an applicable light source for indoor and outdoor lighting, city beautifying, landscape facilities, and municipal engineering etc. Conventional LED has superior characteristics such as long life time, low power consumption, high contrast, and wide viewing angle. Recently, LED with high color-rendering index and special spectral characteristics has received more and more attention. This paper is intended to report a solar spectrum simulated by multichip LED light source. The typical solar spectrum of 5500k released by CIE was simulated as a reference. Four types of LEDs with different spectral power distributions would be used in the LED light source, which included a 430nm LED, a 480nm LED, a 500nm LED and a white LED. In order to obtain better simulation results, the white LED was achieved by a 450nm LED chip with the mixture of phosphor. The phosphor combination was prepared by mixing green phosphor, yellow phosphor and red phosphor in a certain proportion. The multichip LED light source could provide a high fidelity spectral match with the typical solar spectrum of 5500k by adjusting injection current to each device. The luminous flux, CIE chromaticity coordinate x, y, CCT, and Ra were 104.7 lm, 0.3337, 0.3681, 5460K, and 88.6, respectively. Because of high color-rendering index and highly match to the solar spectrum, the multichip LED light source is a competitive candidate for applications where special spectral is required, such as colorimetric measurements, visual inspection, gemstone identification and agriculture.

  7. A novel method of spectrum stabilization

    International Nuclear Information System (INIS)

    Sidhu, N.P.S.

    1978-01-01

    A new type of spectrum stabilizer for a scintillation spectrometer is described. A pulse light source DM 160 is used to introduce an artificial peak in the spectrum at a convenient energy. The centroid of pulse spectrum corresponding to artificial peak is compared with that of suitable reference pulses obtained from the DM 160 driver circuit. Any drift in artificial peak produces a d.c. voltage at the output of centroid comparator and this voltage is used to control the gain of variable gain amplifier to counter the drift. With suitable adjustment the effect of any variation in pulse height of DM 160 driving pulse can be compensated so that the spectrometer gain is independent of any variation, drift etc. in the height of pulse driving DM 160 tube. This circuit is simple and gives improved performance compared to 2 channel method of obtaining the control voltage for variable gain amplifier. (author)

  8. Selective optical contacting for solar spectrum management

    Science.gov (United States)

    Yang, Jianfeng; Chen, Weijian; Wang, Bo; Zhang, Zhilong; Huang, Shujuan; Shrestha, Santosh; Wen, Xiaoming; Patterson, Robert; Conibeer, Gavin

    2017-02-01

    Solar spectrum management using up/down conversion is an important method to improve the photovoltaic energy conversion efficiency. It asks for a monochromatic luminescence absorption at the band edge of the photovoltaic device to reduce both the sub-band-gap and over-band-gap energy losses. Here, we demonstrate an energy selective optical contacting concept to improve the luminescence transfer efficiency for spectrum management. By increasing both the luminescence emission and re-absorption ability through photonic resonance, an efficient photon transfer channel could be established between the luminescence emitter and the photovoltaic component in a near-field region. This concept is not only able to compensate the insufficient band edge absorption ability of the photovoltaic device, but also to break the far-field limitation of luminescence radiation. The energy selection on the optical spectrum naturally imposed by the mode resonance is also helpful to improve the monochromaticity of the luminescence yield. In this paper, a photonic crystal cavity is used to realize the optical contacting concept between a thin silicon film and spectrum converter. The optical power and photon flux transferred between different components are calculated analytically using the electromagnetic Green's function. The corresponding radiative dipole moment is estimated by the fluctuation-dissipation theorem. The example shows an over 80 times enhancement in the luminescence absorbance by the silicon layer, illustrating the great potential of this concept to be applied on nano-structured photovoltaic devices.

  9. SOLAR-ISS: A new reference spectrum based on SOLAR/SOLSPEC observations

    Science.gov (United States)

    Meftah, M.; Damé, L.; Bolsée, D.; Hauchecorne, A.; Pereira, N.; Sluse, D.; Cessateur, G.; Irbah, A.; Bureau, J.; Weber, M.; Bramstedt, K.; Hilbig, T.; Thiéblemont, R.; Marchand, M.; Lefèvre, F.; Sarkissian, A.; Bekki, S.

    2018-03-01

    Context. Since April 5, 2008 and up to February 15, 2017, the SOLar SPECtrometer (SOLSPEC) instrument of the SOLAR payload on board the International Space Station (ISS) has performed accurate measurements of solar spectral irradiance (SSI) from the middle ultraviolet to the infrared (165 to 3088 nm). These measurements are of primary importance for a better understanding of solar physics and the impact of solar variability on climate. In particular, a new reference solar spectrum (SOLAR-ISS) is established in April 2008 during the solar minima of cycles 23-24 thanks to revised engineering corrections, improved calibrations, and advanced procedures to account for thermal and aging corrections of the SOLAR/SOLSPEC instrument. Aims: The main objective of this article is to present a new high-resolution solar spectrum with a mean absolute uncertainty of 1.26% at 1σ from 165 to 3000 nm. This solar spectrum is based on solar observations of the SOLAR/SOLSPEC space-based instrument. Methods: The SOLAR/SOLSPEC instrument consists of three separate double monochromators that use concave holographic gratings to cover the middle ultraviolet (UV), visible (VIS), and infrared (IR) domains. Our best ultraviolet, visible, and infrared spectra are merged into a single absolute solar spectrum covering the 165-3000 nm domain. The resulting solar spectrum has a spectral resolution varying between 0.6 and 9.5 nm in the 165-3000 nm wavelength range. We build a new solar reference spectrum (SOLAR-ISS) by constraining existing high-resolution spectra to SOLAR/SOLSPEC observed spectrum. For that purpose, we account for the difference of resolution between the two spectra using the SOLAR/SOLSPEC instrumental slit functions. Results: Using SOLAR/SOLSPEC data, a new solar spectrum covering the 165-3000 nm wavelength range is built and is representative of the 2008 solar minimum. It has a resolution better than 0.1 nm below 1000 nm and 1 nm in the 1000-3000 nm wavelength range. The new

  10. Stability of Polymer Solar Cells

    DEFF Research Database (Denmark)

    Jørgensen, Mikkel; Norrman, Kion; Gevorgyan, Suren

    2012-01-01

    Organic photovoltaics (OPVs) evolve in an exponential manner in the two key areas of efficiency and stability. The power conversion efficiency (PCE) has in the last decade been increased by almost a factor of ten approaching 10%. A main concern has been the stability that was previously measured ...

  11. Full-spectrum volumetric solar thermal conversion via photonic nanofluids.

    Science.gov (United States)

    Liu, Xianglei; Xuan, Yimin

    2017-10-12

    Volumetric solar thermal conversion is an emerging technique for a plethora of applications such as solar thermal power generation, desalination, and solar water splitting. However, achieving broadband solar thermal absorption via dilute nanofluids is still a daunting challenge. In this work, full-spectrum volumetric solar thermal conversion is demonstrated over a thin layer of the proposed 'photonic nanofluids'. The underlying mechanism is found to be the photonic superposition of core resonances, shell plasmons, and core-shell resonances at different wavelengths, whose coexistence is enabled by the broken symmetry of specially designed composite nanoparticles, i.e., Janus nanoparticles. The solar thermal conversion efficiency can be improved by 10.8% compared with core-shell nanofluids. The extinction coefficient of Janus dimers with various configurations is also investigated to unveil the effects of particle couplings. This work provides the possibility to achieve full-spectrum volumetric solar thermal conversion, and may have potential applications in efficient solar energy harvesting and utilization.

  12. Stability Issues on Perovskite Solar Cells

    Directory of Open Access Journals (Sweden)

    Xing Zhao

    2015-11-01

    Full Text Available Organo lead halide perovskite materials like methylammonium lead iodide (CH3NH3PbI3 and formamidinium lead iodide (HC(NH22PbI3 show superb opto-electronic properties. Based on these perovskite light absorbers, power conversion efficiencies of the perovskite solar cells employing hole transporting layers have increased from 9.7% to 20.1% within just three years. Thus, it is apparent that perovskite solar cell is a promising next generation photovoltaic technology. However, the unstable nature of perovskite was observed when exposing it to continuous illumination, moisture and high temperature, impeding the commercial development in the long run and thus becoming the main issue that needs to be solved urgently. Here, we discuss the factors affecting instability of perovskite and give some perspectives about further enhancement of stability of perovskite solar cell.

  13. Full Spectrum Diffused and Beamed Solar Energy Application Using Optical Fibre

    OpenAIRE

    Majumdar, M. R. Dutta; Das, Debasish

    2007-01-01

    Existing solar energy application systems use small fraction of full spectrum of solar energy. So attempts are made to show how full spectrum solar energy can be used for diffused and beamed form of incident solar energy. Luminescent Solar Concentrator (LSC) principle with optical fibre in diffused sun light and dielectric mirror separation technique with optical fibre in beamed form are discussed. Comparison of both the cases are done. Keywords: full spectrum, solar photonics, diffused solar...

  14. Solar spectrum from 1173 to 1324 A

    International Nuclear Information System (INIS)

    Chipman, E.; Bruner, E.C. Jr.

    1975-01-01

    We present some of the results of a rocket flight which obtained a high-resolution stigmatic spectrum of the Sun in the region 1173--1324 A. A list of 179 lines observed in this region is presented, with intensities, widths, and approximate excitation classes for each line. A reproduction and finding chart of the spectrum is included, along with discussion of some individual lines of special interest

  15. Patterning of graphite nanocones for broadband solar spectrum absorption

    Directory of Open Access Journals (Sweden)

    Yaoran Sun

    2015-06-01

    Full Text Available We experimentally demonstrate a broadband vis-NIR absorber consisting of 300-400 nm nanocone structures on highly oriented pyrolytic graphite. The nanocone structures are fabricated through simple nanoparticle lithography process and analyzed with three-dimensional finite-difference time-domain methods. The measured absorption reaches an average level of above 95% over almost the entire solar spectrum and agrees well with the simulation. Our simple process offers a promising material for solar-thermal devices.

  16. Stability and Degradation of Polymer Solar cells

    DEFF Research Database (Denmark)

    Norrman, Kion

    The current state-of-the-art allows for roll-to-roll manufacture of polymer solar cells in high volume with stability and efficiency sufficient to grant success in low-energy applications. However, further improvement is needed for the successful application of the devices in real life applications....... This is obtained by detailed knowledge of the degradation mechanisms. Methods to compare and standardize device stability are urgently needed. Methodologies to study failure mechanism that are based on physical processes (e.g. morphological changes) are well-established. However, methodologies to study chemical...... degradation mechanisms are currently scarce. An overview of known degradation mechanisms will be presented and discussed in relation to state-of-the-art methodologies to study failure mechanisms with focus on chemical degradation....

  17. The high-resolution extraterrestrial solar spectrum (QASUMEFTS determined from ground-based solar irradiance measurements

    Directory of Open Access Journals (Sweden)

    J. Gröbner

    2017-09-01

    Full Text Available A high-resolution extraterrestrial solar spectrum has been determined from ground-based measurements of direct solar spectral irradiance (SSI over the wavelength range from 300 to 500 nm using the Langley-plot technique. The measurements were obtained at the Izaña Atmospheric Research Centre from the Agencia Estatal de Meteorología, Tenerife, Spain, during the period 12 to 24 September 2016. This solar spectrum (QASUMEFTS was combined from medium-resolution (bandpass of 0.86 nm measurements of the QASUME (Quality Assurance of Spectral Ultraviolet Measurements in Europe spectroradiometer in the wavelength range from 300 to 500 nm and high-resolution measurements (0.025 nm from a Fourier transform spectroradiometer (FTS over the wavelength range from 305 to 380 nm. The Kitt Peak solar flux atlas was used to extend this high-resolution solar spectrum to 500 nm. The expanded uncertainties of this solar spectrum are 2 % between 310 and 500 nm and 4 % at 300 nm. The comparison of this solar spectrum with solar spectra measured in space (top of the atmosphere gave very good agreements in some cases, while in some other cases discrepancies of up to 5 % were observed. The QASUMEFTS solar spectrum represents a benchmark dataset with uncertainties lower than anything previously published. The metrological traceability of the measurements to the International System of Units (SI is assured by an unbroken chain of calibrations leading to the primary spectral irradiance standard of the Physikalisch-Technische Bundesanstalt in Germany.

  18. Technology for computer-stabilized peak of NaI(Tl) gamma spectrum

    International Nuclear Information System (INIS)

    Chen Jianzhen; Guo Lanying; Ling Qiu; Qu Guopu; Zhao Lihong; Hu Chuangye

    2005-01-01

    An improved technology for spectrum stabilization of NaI(Tl) gamma spectrum was introduced. This technology is based on the system using a reference peak, which is equivalent gamma peak of 241 Am source. The computer seeks peak's position deviation and computes adjust value of programmable amplifier and controls programmable amplifier to stabilize spectrum by digital PID. This is a technology of spectrum stabilizing with 'hardware + reference-peak + software' and has high stability and fast speed of spectrum stabilizing. (author)

  19. Enhancing Stability of Perovskite Solar Cells to Moisture by the Facile Hydrophobic Passivation.

    Science.gov (United States)

    Hwang, Insung; Jeong, Inyoung; Lee, Jinwoo; Ko, Min Jae; Yong, Kijung

    2015-08-12

    In this study, a novel and facile passivation process for a perovskite solar cell is reported. Poor stability in ambient atmosphere, which is the most critical demerit of a perovskite solar cell, is overcome by a simple passivation process using a hydrophobic polymer layer. Teflon, the hydrophobic polymer, is deposited on the top of a perovskite solar cell by a spin-coating method. With the hydrophobic passivation, the perovskite solar cell shows negligible degradation after a 30 day storage in ambient atmosphere. Suppressed degradation of the perovskite film is proved in various ways: X-ray diffraction, light absorption spectrum, and quartz crystal microbalance. This simple but effective passivation process suggests new kind of approach to enhance stability of perovskite solar cells to moisture.

  20. Holographic spectrum-splitting optical systems for solar photovoltaics

    Science.gov (United States)

    Zhang, Deming

    Solar energy is the most abundant source of renewable energy available. The relatively high cost prevents solar photovoltaic (PV) from replacing fossil fuel on a larger scale. In solar PV power generation the cost is reduced with more efficient PV technologies. In this dissertation, methods to improve PV conversion efficiency with holographic optical components are discussed. The tandem multiple-junction approach has achieved very high conversion efficiency. However it is impossible to manufacture tandem PV cells at a low cost due to stringent fabrication standards and limited material types that satisfy lattice compatibility. Current produced by the tandem multi-junction PV cell is limited by the lowest junction due to series connection. Spectrum-splitting is a lateral multi-junction concept that is free of lattice and current matching constraints. Each PV cell can be optimized towards full absorption of a spectral band with tailored light-trapping schemes. Holographic optical components are designed to achieve spectrum-splitting PV energy conversion. The incident solar spectrum is separated onto multiple PV cells that are matched to the corresponding spectral band. Holographic spectrum-splitting can take advantage of existing and future low-cost technologies that produces high efficiency thin-film solar cells. Spectrum-splitting optical systems are designed and analyzed with both transmission and reflection holographic optical components. Prototype holograms are fabricated and high optical efficiency is achieved. Light-trapping in PV cells increases the effective optical path-length in the semiconductor material leading to improved absorption and conversion efficiency. It has been shown that the effective optical path length can be increased by a factor of 4n2 using diffusive surfaces. Ultra-light-trapping can be achieved with optical filters that limit the escape angle of the diffused light. Holographic reflection gratings have been shown to act as angle

  1. Stability and degradation mechanisms in organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Ecker, Bernhard

    2012-04-26

    This thesis deals with stability improvements and the investigation of degradation mechanisms in organic solar cells. Organic solar cells have been in the focus of extensive academic research for over almost two decades and are currently entering the market in small scale applications. For successful large scale applications, next to the improvement of the power conversion efficiency, the stability of organic solar cells has to be increased. This thesis is dedicated to the investigation of novel materials and architectures to study stability-related issues and degradation mechanisms in order to contribute to the basic understanding of the working principles of organic solar cells. Here, impedance spectroscopy, a frequency domain technique, is used to gain information about stability and degradation mechanisms in organic solar cells. In combination with systematic variations in the preparation of solar cells, impedance spectroscopy gives the possibility to differentiate between interface and bulk dominated effects. Additionally, impedance spectroscopy gives access to the dielectric properties of the device, such as capacitance. This offers among other things the opportunity to probe the charge carrier concentration and the density of states. Another powerful way of evaluation is the combination of experimentally obtained impedance spectra with equivalent circuit modelling. The thesis presents results on novel materials and solar cell architectures for efficient hole and electron extraction. This indicates the importance of knowledge over interlayers and interfaces for improving both the efficiency and stability of organic solar cells.

  2. Design and Analysis of Hybrid Solar Lighting and Full-Spectrum Solar Energy Systems

    International Nuclear Information System (INIS)

    Muhs, J.D.

    2001-01-01

    This paper describes a systems-level design and analysis of a new approach for improving the energy efficiency and affordability of solar energy in buildings, namely, hybrid solar lighting and full-spectrum solar energy systems. By using different portions of the solar spectrum simultaneously for multiple end-use applications in buildings, the proposed system offers unique advantages over other alternatives for using sunlight to displace electricity (conventional topside daylighting and solar technologies). Our preliminary work indicates that hybrid solar lighting, a method of collecting and distributing direct sunlight for lighting purposes, will alleviate many of the problems with passive daylighting systems of today, such as spatial and temporal variability, glare, excess illumination, cost, and energy efficiency. Similarly, our work suggests that the most appropriate use of the visible portion of direct, nondiffuse sunlight from an energy-savings perspective is to displace electric light rather than generate electricity. Early estimates detailed in this paper suggest an anticipated system cost of well under$2.0/Wp and 5-11(cents)/kWh for displaced and generated electricity in single-story commercial building applications. Based on a number of factors discussed in the paper, including sunlight availability, building use scenarios, time-of-day electric utility rates, cost, and efficacy of the displaced electric lights, the simple payback of this approach in many applications could eventually be well under 5 years

  3. New method of interpretation of the solar spectrum lines

    International Nuclear Information System (INIS)

    Sitnik, G.F.

    1975-01-01

    Close triplet lines, which appear from a common low level or from low sublevels with small energy difference are used. It is supposed that for such lines both the function of the source in line and the frequency dependence of the selective coefficient of absorption are the same over any depth of the region of line production in the atmosphere and change with the depth equally. The residual intensities of some lines of the triplet, which are measured for every line at a number of profile points (at the same distance from its center and at different distances from the solar limb center), serve as initial material. The intensities are expressed in terms of the intensity of the continuous spectrum in the center of the solar limb for the average wave length of the triplet interval. Such observations avoid the usual assumption about the source function constancy in line inside the line. On the contrary, the frequency dependence of this function is clarified by the use of this method. Calculations make it possible to determine the source function in line and its long-wave dependence inside the line; to derive a solar atmosphere model and to determine the source function in the continuous spectrum in accordance with observations at profile points in its middle part and in the wing; to find the relation between the selective and continuous absorption coefficients in the dependence on the optical depth in the continuous spectrum; and to find the long-wave dependences of coefficients for both the selective absorption and the selective emission at different optical depths

  4. Solarelastic Stability of Solar Sail Structures

    Data.gov (United States)

    National Aeronautics and Space Administration — In order to avoid an unintended failure in proposed Solar Sail spacecraft due to solarelastic interactions it is important to develop an analytical framework for...

  5. Stability and Degradation of Organic and Polymer Solar Cells

    DEFF Research Database (Denmark)

    Organic photovoltaics (OPV) are a new generation of solar cells with the potential to offer very short energy pay back times, mechanical flexibility and significantly lower production costs compared to traditional crystalline photovoltaic systems. A weakness of OPV is their comparative instability...... during operation and this is a critical area of research towards the successful development and commercialization of these 3rd generation solar cells. Covering both small molecule and polymer solar cells, Stability and Degradation of Organic and Polymer Solar Cells summarizes the state of the art...... understanding of stability and provides a detailed analysis of the mechanisms by which degradation occurs. Following an introductory chapter which compares different photovoltaic technologies, the book focuses on OPV degradation, discussing the origin and characterization of the instability and describing...

  6. Long term optical stability of fluorescent solar concentrator plates

    NARCIS (Netherlands)

    Slooff, L.H.; Bakker, N.J.; Sommeling, P.M.; Büchtemann, A.; Wedel, A.; Sark, W.G.J.H.M. van

    2014-01-01

    Fluorescent solar concentrators offer an alternative approach for low-cost photovoltaic energy conversion. For successful application, not only the power conversion efficiency and cost are important, but also lifetime or stability of the devices. As today’s concentrator is made of polymer sheets

  7. Long-term optical stability of fluorescent solar concentrator plates

    NARCIS (Netherlands)

    Slooff, Lenneke H.; Bakker, Nicolaas J.; Sommeling, Paul M.; Büchtemann, Andreas; Wedel, Armin; Van Sark, Wilfried G J H M

    2014-01-01

    Fluorescent solar concentrators offer an alternative approach for low-cost photovoltaic energy conversion. For successful application, not only the power conversion efficiency and cost are important, but also lifetime or stability of the devices. As today's concentrator is made of polymer sheets

  8. Pointing stability of Hinode and requirements for the next Solar mission Solar-C

    Science.gov (United States)

    Katsukawa, Y.; Masada, Y.; Shimizu, T.; Sakai, S.; Ichimoto, K.

    2017-11-01

    It is essential to achieve fine pointing stability in a space mission aiming for high resolutional observations. In a future Japanese solar mission SOLAR-C, which is a successor of the HINODE (SOLAR-B) mission, we set targets of angular resolution better than 0.1 arcsec in the visible light and better than 0.2 - 0.5 arcsec in EUV and X-rays. These resolutions are twice to five times better than those of corresponding instruments onboard HINODE. To identify critical items to achieve the requirements of the pointing stability in SOLAR-C, we assessed in-flight performance of the pointing stability of HINODE that achieved the highest pointing stability in Japanese space missions. We realized that one of the critical items that have to be improved in SOLAR-C is performance of the attitude stability near the upper limit of the frequency range of the attitude control system. The stability of 0.1 arcsec (3σ) is required in the EUV and X-ray telescopes of SOLAR-C while the HINODE performance is slightly worse than the requirement. The visible light telescope of HINODE is equipped with an image stabilization system inside the telescope, which achieved the stability of 0.03 arcsec (3σ) by suppressing the attitude jitter in the frequency range lower than 10 Hz. For further improvement, it is expected to suppress disturbances induced by resonance between the telescope structures and disturbances of momentum wheels and mechanical gyros in the frequency range higher than 100 Hz.

  9. Recent progress in stabilizing hybrid perovskites for solar cell applications

    Science.gov (United States)

    Chen, Jianqing; Cai, Xin; Yang, Donghui; Song, Dan; Wang, Jiajia; Jiang, Jinghua; Ma, Aibin; Lv, Shiquan; Hu, Michael Z.; Ni, Chaoying

    2017-07-01

    Hybrid inorganic-organic perovskites have quickly evolved as a promising group of materials for solar cells and optoelectronic applications mainly owing to the inexpensive materials, relatively simple and versatile fabrication and high power conversion efficiency (PCE). The certified energy conversion efficiency for perovskite solar cell (PSC) has reached above 20%, which is compatible to the current best for commercial applications. However, long-term stabilities of the materials and devices remain to be the biggest challenging issue for realistic implementation of the PSCs. This article discusses the key issues related to the stability of perovskite absorbing layer including crystal structural stability, chemical stability under moisture, oxygen, illumination and interface reaction, effects of electron-transporting materials (ETM), hole-transporting materials (HTM), contact electrodes, ion migration and preparation conditions. Towards the end, prospective strategies for improving the stability of PSCs are also briefly discussed and summarized. We focus on recent understanding of the stability of materials and devices and our perspectives about the strategies for the stability improvement.

  10. Attitude Dynamics and Stability of a Simple Solar Photon Thruster

    Directory of Open Access Journals (Sweden)

    Anna D. Guerman

    2013-01-01

    Full Text Available This paper is dedicated to the development of a model of the attitude dynamics for a nonideal Simple Solar Photon Thruster (SSPT and to the analysis of sailcraft motions with respect to their centre of mass. Derivation of the expressions for force and torque due to solar radiation that is valid for the case, when there is a misalignment of the SSPT axis with the sun direction, is followed by study of sailcraft dynamics and stability properties. Analysis of stability shows that an ideally reflecting sail is unstable, while for a sailcraft with nonideal collector, the symmetry axis is stable with respect to the Sun direction for large variety of system parameters. The motion around symmetry axis is always unstable and requires an active stabilizer.

  11. Diagnoses of Autism Spectrum Disorders in Germany: Time Trends in Administrative Prevalence and Diagnostic Stability

    Science.gov (United States)

    Bachmann, Christian J.; Gerste, Bettina; Hoffmann, Falk

    2018-01-01

    For Germany, no data on trends in autism spectrum disorder diagnoses are available. The primary aim of this study was to establish the time trends in the administrative prevalence of autism spectrum disorder diagnoses. The second aim was to assess the stability of autism spectrum disorder diagnoses over time. We analysed administrative outpatient…

  12. Solar Dynamic Power System Stability Analysis and Control

    Science.gov (United States)

    Momoh, James A.; Wang, Yanchun

    1996-01-01

    The objective of this research is to conduct dynamic analysis, control design, and control performance test of solar power system. Solar power system consists of generation system and distribution network system. A bench mark system is used in this research, which includes a generator with excitation system and governor, an ac/dc converter, six DDCU's and forty-eight loads. A detailed model is used for modeling generator. Excitation system is represented by a third order model. DDCU is represented by a seventh order system. The load is modeled by the combination of constant power and constant impedance. Eigen-analysis and eigen-sensitivity analysis are used for system dynamic analysis. The effects of excitation system, governor, ac/dc converter control, and the type of load on system stability are discussed. In order to improve system transient stability, nonlinear ac/dc converter control is introduced. The direct linearization method is used for control design. The dynamic analysis results show that these controls affect system stability in different ways. The parameter coordination of controllers are recommended based on the dynamic analysis. It is concluded from the present studies that system stability is improved by the coordination of control parameters and the nonlinear ac/dc converter control stabilize system oscillation caused by the load change and system fault efficiently.

  13. A Deeper Understanding of Stability in the Solar Wind: Applying Nyquist's Instability Criterion to Wind Faraday Cup Data

    Science.gov (United States)

    Alterman, B. L.; Klein, K. G.; Verscharen, D.; Stevens, M. L.; Kasper, J. C.

    2017-12-01

    Long duration, in situ data sets enable large-scale statistical analysis of free-energy-driven instabilities in the solar wind. The plasma beta and temperature anisotropy plane provides a well-defined parameter space in which a single-fluid plasma's stability can be represented. Because this reduced parameter space can only represent instability thresholds due to the free energy of one ion species - typically the bulk protons - the true impact of instabilities on the solar wind is under estimated. Nyquist's instability criterion allows us to systematically account for other sources of free energy including beams, drifts, and additional temperature anisotropies. Utilizing over 20 years of Wind Faraday cup and magnetic field observations, we have resolved the bulk parameters for three ion populations: the bulk protons, beam protons, and alpha particles. Applying Nyquist's criterion, we calculate the number of linearly growing modes supported by each spectrum and provide a more nuanced consideration of solar wind stability. Using collisional age measurements, we predict the stability of the solar wind close to the sun. Accounting for the free-energy from the three most common ion populations in the solar wind, our approach provides a more complete characterization of solar wind stability.

  14. Contribution of Strong Discontinuities to the Power Spectrum of the Solar Wind

    International Nuclear Information System (INIS)

    Borovsky, Joseph E.

    2010-01-01

    Eight and a half years of magnetic field measurements (2 22 samples) from the ACE spacecraft in the solar wind at 1 A.U. are analyzed. Strong (large-rotation-angle) discontinuities in the solar wind are collected and measured. An artificial time series is created that preserves the timing and amplitudes of the discontinuities. The power spectral density of the discontinuity series is calculated and compared with the power spectral density of the solar-wind magnetic field. The strong discontinuities produce a power-law spectrum in the ''inertial subrange'' with a spectral index near the Kolmogorov -5/3 index. The discontinuity spectrum contains about half of the power of the full solar-wind magnetic field over this ''inertial subrange.'' Warnings are issued about the significant contribution of discontinuities to the spectrum of the solar wind, complicating interpretation of spectral power and spectral indices.

  15. Applying Nyquist's method for stability determination to solar wind observations

    Science.gov (United States)

    Klein, Kristopher G.; Kasper, Justin C.; Korreck, K. E.; Stevens, Michael L.

    2017-10-01

    The role instabilities play in governing the evolution of solar and astrophysical plasmas is a matter of considerable scientific interest. The large number of sources of free energy accessible to such nearly collisionless plasmas makes general modeling of unstable behavior, accounting for the temperatures, densities, anisotropies, and relative drifts of a large number of populations, analytically difficult. We therefore seek a general method of stability determination that may be automated for future analysis of solar wind observations. This work describes an efficient application of the Nyquist instability method to the Vlasov dispersion relation appropriate for hot, collisionless, magnetized plasmas, including the solar wind. The algorithm recovers the familiar proton temperature anisotropy instabilities, as well as instabilities that had been previously identified using fits extracted from in situ observations in Gary et al. (2016). Future proposed applications of this method are discussed.

  16. NonLTE ANALYSIS OF THE NaI LINES IN THE SOLAR SPECTRUM

    OpenAIRE

    Ivanova, D. V.; Shimansky, V. V.

    2017-01-01

    Solar spectrum of Nal lines by method of the nonLTE analysis is investigated. It shown, that in atmosphere of the Sun the Nal is in moderate ”overrecombination”. The analysis of influence of atomic data, models of atmospheres and damping constants for nonLTE deviation and sodium abundances is made. Observational solar spectrum of strong lines Nal has been synthesized in good approximation. On summary data of 15 lines the sodium abundance is determined:-5.78dex.

  17. `Fingerprint' Fine Structure in the Solar Decametric Radio Spectrum Solar Physics

    Science.gov (United States)

    Zlotnik, E. Y.; Zaitsev, V. V.; Melnik, V. N.; Konovalenko, A. A.; Dorovskyy, V. V.

    2015-07-01

    We study a unique fine structure in the dynamic spectrum of the solar radio emission discovered by the UTR-2 radio telescope (Kharkiv, Ukraine) in the frequency band of 20 - 30 MHz. The structure was observed against the background of a broadband type IV radio burst and consisted of parallel drifting narrow bands of enhanced emission and absorption on the background emission. The observed structure differs from the widely known zebra pattern at meter and decimeter wavelengths by the opposite directions of the frequency drift within a single stripe at a given time. We show that the observed properties can be understood in the framework of the radiation mechanism by virtue of the double plasma resonance effect in a nonuniform coronal magnetic trap. We propose a source model providing the observed frequency drift of the stripes.

  18. Photocatalytic ROS production and phototoxicity of titanium dioxide nanoparticles is dependent on solar UV radiation spectrum

    Science.gov (United States)

    Generation of reactive oxygen species (ROS) by titanium dioxide nanoparticles (nano-TiO2) and its consequent phototoxicity to Daphnia magna were measured under different solar UV radiation spectrum by applying a series of optical filters in a solar simulator. Removing UVB (280-32...

  19. Dye-sensitized solar cells and solar module using polymer electrolytes: Stability and performance investigations

    Directory of Open Access Journals (Sweden)

    Jilian Nei de Freitas

    2006-01-01

    Full Text Available We present recent results on solid-state dye-sensitized solar cell research using a polymer electrolyte based on a poly(ethylene oxide derivative. The stability and performance of the devices have been improved by a modification in the method of assembly of the cells and by the addition of plasticizers in the electrolyte. After 30 days of solar irradiation (100 mW cm-2 no changes in the cell's efficiency were observed using this new method. The effect of the active area size on cell performance and the first results obtained for the first solar module composed of 4.5 cm2 solid-state solar cells are also presented.

  20. Hybrid Model of Inhomogeneous Solar Wind Plasma Heating by Alfven Wave Spectrum: Parametric Studies

    Science.gov (United States)

    Ofman, L.

    2010-01-01

    Observations of the solar wind plasma at 0.3 AU and beyond show that a turbulent spectrum of magnetic fluctuations is present. Remote sensing observations of the corona indicate that heavy ions are hotter than protons and their temperature is anisotropic (T(sub perpindicular / T(sub parallel) >> 1). We study the heating and the acceleration of multi-ion plasma in the solar wind by a turbulent spectrum of Alfvenic fluctuations using a 2-D hybrid numerical model. In the hybrid model the protons and heavy ions are treated kinetically as particles, while the electrons are included as neutralizing background fluid. This is the first two-dimensional hybrid parametric study of the solar wind plasma that includes an input turbulent wave spectrum guided by observation with inhomogeneous background density. We also investigate the effects of He++ ion beams in the inhomogeneous background plasma density on the heating of the solar wind plasma. The 2-D hybrid model treats parallel and oblique waves, together with cross-field inhomogeneity, self-consistently. We investigate the parametric dependence of the perpendicular heating, and the temperature anisotropy in the H+-He++ solar wind plasma. It was found that the scaling of the magnetic fluctuations power spectrum steepens in the higher-density regions, and the heating is channeled to these regions from the surrounding lower-density plasma due to wave refraction. The model parameters are applicable to the expected solar wind conditions at about 10 solar radii.

  1. High stability of benzotriazole and benzodithiophene containing medium band-gap polymer solar cell

    DEFF Research Database (Denmark)

    Unay, Hande; dos Reis Benatto, Gisele A.; Beliatis, Michail J.

    2018-01-01

    The improvement of polymer solar cell stability is a challenge for the scientists and has significant implications commercially. In this study, we investigated the stability of a novel P-SBTBDT active material applied in an inverted type solar cell. Detailed stability experiments comprising shelf......-in phase with T50 from 700 to 840 h, with some P-SBTBDT solar cells did not reach T50 in the time span of the test. Degradation tests on the P-SBTBDT solar cells which were carried out under natural solar light indicated that T40 was reached after 840 h. The results of dark, light, damp and dry stability...

  2. Photo stability Assessment in Amorphous-Silicon Solar Cells

    International Nuclear Information System (INIS)

    Gandia, J. J.; Carabe, J.; Fabero, F.; Jimenez, R.; Rivero, J. M.

    1999-01-01

    The present status of amorphous-silicon-solar-cell research and development at CIEMAT requires the possibility to characterise the devices prepared from the point of view of their stability against sunlight exposure. Therefore a set of tools providing such a capacity has been developed. Together with an introduction to photovoltaic applications of amorphous silicon and to the photodegradation problem, the present work describes the process of setting up these tools. An indoor controlled photodegradation facility has been designed and built, and a procedure has been developed for the measurement of J-V characterisation in well established conditions. This method is suitable for all kinds of solar cells, even for those for which no model is still available. The photodegradation and characterisation of some cells has allowed to validate both the new testing facility and method. (Author) 14 refs

  3. The solar spectrum from 1173 to 1324 A

    Science.gov (United States)

    Chipman, E.; Bruner, E. C., Jr.

    1975-01-01

    We present some of the results of a rocket flight which obtained a high-resolution stigmatic spectrum of the sun in the region 1173-1324 A. A list of 179 lines observed in this region is presented, with intensities, widths, and approximate excitation classes for each line. A reproduction and finding chart of the spectrum is included, along with discussion of some individual lines of special interest.

  4. Diagnostic Stability in Very Young Children with Autism Spectrum Disorders

    Science.gov (United States)

    Kleinman, Jamie M.; Ventola, Pamela E.; Pandey, Juhi; Verbalis, Alyssa D.; Barton, Marianne; Hodgson, Sarah; Green, James; Dumont-Mathieu, Thyde; Robins, Diana L.; Fein, Deborah

    2008-01-01

    Autism Spectrum Disorders (ASD) diagnosis in very young children may be delayed due to doubts about validity. In this study, 77 children received a diagnostic and developmental evaluation between 16 and 35 months and also between 42 and 82 months. Diagnoses based on clinical judgment, Childhood Autism Rating Scale, and the Autism Diagnostic…

  5. Pairing of near-ultraviolet solar cells with electrochromic windows for smart management of the solar spectrum

    Science.gov (United States)

    Davy, Nicholas C.; Sezen-Edmonds, Melda; Gao, Jia; Lin, Xin; Liu, Amy; Yao, Nan; Kahn, Antoine; Loo, Yueh-Lin

    2017-08-01

    Current smart window technologies offer dynamic control of the optical transmission of the visible and near-infrared portions of the solar spectrum to reduce lighting, heating and cooling needs in buildings and to improve occupant comfort. Solar cells harvesting near-ultraviolet photons could satisfy the unmet need of powering such smart windows over the same spatial footprint without competing for visible or infrared photons, and without the same aesthetic and design constraints. Here, we report organic single-junction solar cells that selectively harvest near-ultraviolet photons, produce open-circuit voltages eclipsing 1.6 V and exhibit scalability in power generation, with active layers (10 cm2) substantially larger than those typical of demonstration organic solar cells (0.04-0.2 cm2). Integration of these solar cells with a low-cost, polymer-based electrochromic window enables intelligent management of the solar spectrum, with near-ultraviolet photons powering the regulation of visible and near-infrared photons for natural lighting and heating purposes.

  6. Motor Difficulties in Autism Spectrum Disorder: Linking Symptom Severity and Postural Stability

    Science.gov (United States)

    Travers, Brittany G.; Powell, Patrick S.; Klinger, Laura G.; Klinger, Mark R.

    2013-01-01

    Postural stability is a fundamental aspect of motor ability that allows individuals to sustain and maintain the desired physical position of one's body. The present study examined postural stability in average-IQ adolescents and adults with Autism Spectrum Disorder (ASD). Twenty-six individuals with ASD and 26 age-and-IQ-matched individuals…

  7. Production, characterization and stability of organic solar cell devices

    Energy Technology Data Exchange (ETDEWEB)

    Gevorgyan, S A

    2010-01-15

    Despite the fact that the field of organic photovoltaics (OPVs) is in a rapid progress, organic solar cells continue taking backstage roll in the growing markets of various solar technologies. The main challenge of the field is to develop devices that would possess all the optimal properties required for efficient, stable and cheap solar cells, i.e. devices that can deliver high photoconversion efficiencies and long lifetimes and can be efficiently produced in large scales using roll-to-roll coating technologies. This dissertation is primarily devoted to the issues of photoconversion efficiency and device lifetimes. In particular, descriptions of some practical approaches for different device designs and processing of active layer for typical small scale OPV devices were presented. The emphasis was put on some optimizing techniques for processing of active layer that can significantly improve the device photoconversion efficiency. The techniques were further applied for manufacturing and characterization of solar cell devices based on various materials. In particular, a number of thermocleavable polymers were studied and devices based on such materials were produced and characterized. The applicability of such materials in photovoltaic devices was shown and further challenges were discussed. Another task of this work was to manufacture and study inverted device structures and compare their properties with normal structure based devices. Device based on both structure were successfully produced with same level of performance in terms of photoconversion efficiency, yet with totally different stability performance. As another task, metal oxides, such as MoO{sub 3} or V{sub 2}O{sub 5} were studied in solar cell devices as buffer layers instead of PEDOT:PSS. Although the device efficiencies obtained with metal oxides were inferior to PEDOT based device, it was shown that such materials can possibly improve the device efficiency if the processing of the layers is

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

    Science.gov (United States)

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

    2016-05-23

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

  9. A Fundamental Study on Spectrum Center Estimation of Solar Spectral Irradiation by the Statistical Pattern Recognition

    Science.gov (United States)

    Iijima, Aya; Suzuki, Kazumi; Wakao, Shinji; Kawasaki, Norihiro; Usami, Akira

    With a background of environmental problems and energy issues, it is expected that PV systems will be introduced rapidly and connected with power grids on a large scale in the future. For this reason, the concern to which PV power generation will affect supply and demand adjustment in electric power in the future arises and the technique of correctly grasping the PV power generation becomes increasingly important. The PV power generation depends on solar irradiance, temperature of a module and solar spectral irradiance. Solar spectral irradiance is distribution of the strength of the light for every wavelength. As the spectrum sensitivity of solar cell depends on kind of solar cell, it becomes important for exact grasp of PV power generation. Especially the preparation of solar spectral irradiance is, however, not easy because the observational instrument of solar spectral irradiance is expensive. With this background, in this paper, we propose a new method based on statistical pattern recognition for estimating the spectrum center which is representative index of solar spectral irradiance. Some numerical examples obtained by the proposed method are also presented.

  10. Stabilization of mixed waste - Rocky Flats solar ponds

    International Nuclear Information System (INIS)

    Bittner, T.A.; Mathew, S.A.; Henderson, W.C.

    1993-01-01

    Among the wastes that require disposal as part of the Department of Energy's (DOE's) Environmental Restoration Program are large amounts of contaminated sludge and inorganic wastes. Halliburton NUS Corporation was awarded a contract by EG ampersand G Rocky Flats in March 1991 to stabilize mixed waste sludge contained in five solar evaporator ponds and to reprocess billets of solidified waste called Pondcrete and Saltcrete at DOE's Rocky Flats Plant. The scope of the project consists of waste characterization and treatability studies for process development, followed by design, construction and operation of various process trains to remediate different waste forms ranging from solid Pondcrete/Saltcrete blocks to aqueous brine solutions. One of the significant advances made was the development of a durable and certifiable stabilization formulation capable of treating concentrated nitrate solution wastes. The project uses high-volume grout mixing and pumping technologies with process control techniques that accommodate the heterogeneity of the wastes. To comply with all relevant environmental regulations and to provide a safe working atmosphere for plant personnel, Halliburton NUS designed process trains such that all emissions were eliminated during the remediation process. Personnel protection equipment requirements have been downgraded due to safeguards incorporated in the design. The technical and regulatory issues that were encountered would be typical of stabilization efforts underway at other DOE sites. Thus the lessons learned and concepts developed can be expected to have widespread application

  11. Stability of perovskite solar cells on flexible substrates

    Science.gov (United States)

    Tam, Ho Won; Chen, Wei; Liu, Fangzhou; He, Yanling; Leung, Tik Lun; Wang, Yushu; Wong, Man Kwong; Djurišić, Aleksandra B.; Ng, Alan Man Ching; He, Zhubing; Chan, Wai Kin; Tang, Jinyao

    2018-02-01

    Perovskite solar cells are emerging photovoltaic technology with potential for low cost, high efficiency devices. Currently, flexible devices efficiencies over 15% have been achieved. Flexible devices are of significant interest for achieving very low production cost via roll-to-roll processing. However, the stability of perovskite devices remains a significant challenge. Unlike glass substrate which has negligible water vapor transmission rate (WVTR), polymeric flexible film substrates suffer from high moisture permeability. As PET and PEN flexible substrates exhibit higher water permeability then glass, transparent flexible backside encapsulation should be used to maximize light harvesting in perovskite layer while WVTR should be low enough. Wide band gap materials are transparent in the visible spectral range low temperature processable and can be a moisture barrier. For flexible substrates, approaches like atomic layer deposition (ALD) and low temperature solution processing could be used for metal oxide deposition. In this work, ALD SnO2, TiO2, Al2O3 and solution processed spin-on-glass was used as the barrier layer on the polymeric side of indium tin oxide (ITO) coated PEN substrates. The UV-Vis transmission spectra of the prepared substrates were investigated. Perovskite solar cells will be fabricated and stability of the devices were encapsulated with copolymer films on the top side and tested under standard ISOS-L-1 protocol and then compared to the commercial unmodified ITO/PET or ITO/PEN substrates. In addition, devices with copolymer films laminated on both sides successfully surviving more than 300 hours upon continuous AM1.5G illumination were demonstrated.

  12. Broad Spectrum Photoelectrochemical Diodes for Solar Hydrogen Generation

    Energy Technology Data Exchange (ETDEWEB)

    Grimes, Craig A.

    2014-11-26

    Under program auspices we have investigated material chemistries suitable for the solar generation of hydrogen by water photoelectrolysis. We have built upon, and extended, our knowledge base on the synthesis and application of TiO2 nanotube arrays, a material architecture that appears ideal for water photoelectrolysis. To date we have optimized, refined, and greatly extended synthesis techniques suitable for achieving highly ordered TiO2 nanotube arrays of given length, wall thickness, pore diameter, and tube-to-tube spacing for use in water photoelectrolysis. We have built upon this knowledge based to achieve visible light responsive, photocorrosion stable n-type and p-type ternary oxide nanotube arrays for use in photoelectrochemical diodes.

  13. Heating and acceleration of solar wind ions by turbulent wave spectrum in inhomogeneous expanding plasma

    Energy Technology Data Exchange (ETDEWEB)

    Ofman, Leon, E-mail: Leon.Ofman@nasa.gov [Department of Physics, The Catholic University of America, Washington, DC (United States); NASA Goddard Space Flight Center, Greenbelt, MD (United States); Visiting, Department of Geosciences, Tel Aviv University, Tel Aviv (Israel); Ozak, Nataly [Centre for mathematical Plasma Astrophysics, KU Leuven, Celestijnenlaan 200B, 3001 Leuven (Belgium); Viñas, Adolfo F. [NASA Goddard Space Flight Center, Greenbelt, MD (United States)

    2016-03-25

    Near the Sun (< 10R{sub s}) the acceleration, heating, and propagation of the solar wind are likely affected by the background inhomogeneities of the magnetized plasma. The heating and the acceleration of the solar wind ions by turbulent wave spectrum in inhomogeneous plasma is studied using a 2.5D hybrid model. The hybrid model describes the kinetics of the ions, while the electrons are modeled as massless neutralizing fluid in an expanding box approach. Turbulent magnetic fluctuations dominated by power-law frequency spectra, which are evident from in-situ as well as remote sensing measurements, are used in our models. The effects of background density inhomogeneity across the magnetic field on the resonant ion heating are studied. The effect of super-Alfvénic ion drift on the ion heating is investigated. It is found that the turbulent wave spectrum of initially parallel propagating waves cascades to oblique modes, and leads to enhanced resonant ion heating due to the inhomogeneity. The acceleration of the solar wind ions is achieved by the parametric instability of large amplitude waves in the spectrum, and is also affected by the inhomogeneity. The results of the study provide the ion temperature anisotropy and drift velocity temporal evolution due to relaxation of the instability. The non-Maxwellian velocity distribution functions (VDFs) of the ions are modeled in the inhomogeneous solar wind plasma in the acceleration region close to the Sun.

  14. A Method to Reconstruct the Solar-Induced Canopy Fluorescence Spectrum from Hyperspectral Measurements

    Directory of Open Access Journals (Sweden)

    Feng Zhao

    2014-10-01

    Full Text Available A method for canopy Fluorescence Spectrum Reconstruction (FSR is proposed in this study, which can be used to retrieve the solar-induced canopy fluorescence spectrum over the whole chlorophyll fluorescence emission region from 640–850 nm. Firstly, the radiance of the solar-induced chlorophyll fluorescence (Fs at five absorption lines of the solar spectrum was retrieved by a Spectral Fitting Method (SFM. The Singular Vector Decomposition (SVD technique was then used to extract three basis spectra from a training dataset simulated by the model SCOPE (Soil Canopy Observation, Photochemistry and Energy fluxes. Finally, these basis spectra were linearly combined to reconstruct the Fs spectrum, and the coefficients of them were determined by Weighted Linear Least Squares (WLLS fitting with the five retrieved Fs values. Results for simulated datasets indicate that the FSR method could accurately reconstruct the Fs spectra from hyperspectral measurements acquired by instruments of high Spectral Resolution (SR and Signal to Noise Ratio (SNR. The FSR method was also applied to an experimental dataset acquired in a diurnal experiment. The diurnal change of the reconstructed Fs spectra shows that the Fs radiance around noon was higher than that in the morning and afternoon, which is consistent with former studies. Finally, the potential and limitations of this method are discussed.

  15. A Systematic Review of the Diagnostic Stability of Autism Spectrum Disorder

    Science.gov (United States)

    Woolfenden, Sue; Sarkozy, Vanessa; Ridley, Greta; Williams, Katrina

    2012-01-01

    There is debate in the current literature regarding the permanence of an Autism Spectrum Disorder (ASD) diagnosis. We undertook a systematic review of the diagnostic stability of ASD to summarise current evidence. A comprehensive search strategy was used to identify studies. Participants were children with ASD. Risk of bias was assessed by…

  16. Stability and Change in the Cognitive and Adaptive Behaviour Scores of Preschoolers with Autism Spectrum Disorder

    Science.gov (United States)

    Flanagan, Helen E.; Smith, Isabel M.; Vaillancourt, Tracy; Duku, Eric; Szatmari, Peter; Bryson, Susan; Fombonne, Eric; Mirenda, Pat; Roberts, Wendy; Volden, Joanne; Waddell, Charlotte; Zwaigenbaum, Lonnie; Bennett, Teresa; Elsabbagh, Mayada; Georgiades, Stelios

    2015-01-01

    We examined the stability of cognitive and adaptive behaviour standard scores in children with autism spectrum disorder (ASD) between diagnosis and school entry approximately age 6. IQ increased 18 points in 2-year-olds, 12 points in 3-year-olds, and 9 points in 4-year-olds (N = 281). Adaptive behaviour scores increased 4 points across age groups…

  17. Early Diagnosis of Autism Spectrum Disorder: Stability and Change in Clinical Diagnosis and Symptom Presentation

    Science.gov (United States)

    Guthrie, Whitney; Swineford, Lauren B.; Nottke, Charly; Wetherby, Amy M.

    2013-01-01

    Background: Although a diagnosis of autism spectrum disorder (ASD) appears to be stable in children as young as age three, few studies have explored stability of a diagnosis in younger children. Predictive value of diagnostic tools for toddlers and patterns of symptom change are important considerations for clinicians making early diagnoses. Most…

  18. Stability of Early Risk Assessment for Autism Spectrum Disorder in Preterm Infants

    Science.gov (United States)

    Yaari, Maya; Yitzhak, Neta; Harel, Ayelet; Friedlander, Edwa; Bar-Oz, Benjamin; Eventov-Friedman, Smadar; Mankuta, David; Gamliel, Ifat; Yirmiya, Nurit

    2016-01-01

    Stability and change in early autism spectrum disorder risk were examined in a cohort of 99 preterm infants (?34 weeks of gestation) using the Autism Observation Scale for Infants at 8 and 12 months and the Autism Diagnostic Observation Schedule--Toddler Module at 18 months. A total of 21 infants were identified at risk by the Autism Observation…

  19. High resolution atlas of the solar spectrum 2678-2931 A

    Science.gov (United States)

    Allen, M. S.; Mcallister, H. C.; Jefferies, J. T.

    1977-01-01

    A portion of the ultraviolet solar spectrum is presented in this high resolution atlas. The data, originating from a rocket echelle spectrogram obtained on 19 June 1974 of a quiet area near the center of the solar disk, extend from 2678 to 2931 A. The instrument had a nominal resolving power of 200,000 at these wavelengths and the rms precision of the rectified wavelength scale is 15 mA. Absolute intensities are computed by calibration to the absolute measurements of Kohl and Parkinson.

  20. XUV spectrum of C I observed from Skylab during a solar flare

    International Nuclear Information System (INIS)

    Feldman, U.; Brown, C.M.; Doschek, G.A.; Moore, C.E.; Rosenberg, F.D.

    1976-01-01

    An intense spectrum of C I in the wavelength region from 1100 to 2000 A has been recorded by the Naval Research Laboratory normal incidence spectrograph flown on Skylab. The source of the spectrum was a large solar flare. The spectral resolution was about 20 000 at 1200 A. We have identified 69 new lines of C I, and determined 63 new energy levels. The new lines arise from transitions from upper levels of high principal quantum number n where n approximately-greater-than 6. A list of 193 C I lines observed in the spectrum between 1140 and 1931 A is presented, as well as calculated wavelengths for an additional 109 transitions between the new levels and the 2s 2 2p 2 3 P 0 , 1 , 2 levels. The calculated lines fall between 1102 and 1140 A and were not observed in the solar flare spectrum due to low instrumental efficiency at these wavelengths. The relative wavelength accuracy of most of the observed and calculated lines is about +- 0.004 A. The intensities of the C I lines are qualitatively compared with corresponding intensities in the laboratory spectrum

  1. Electromagnetic Spectrum Analysis and Its Influence on the Photoelectric Conversion Efficiency of Solar Cells.

    Science.gov (United States)

    Hu, Kexiang; Ding, Enjie; Wangyang, Peihua; Wang, Qingkang

    2016-06-01

    The electromagnetic spectrum and the photoelectric conversion efficiency of the silicon hexagonal nanoconical hole (SiHNH) arrays based solar cells is systematically analyzed according to Rigorous Coupled Wave Analysis (RCWA) and Modal Transmission Line (MTL) theory. An ultimate efficiency of the optimized SiHNH arrays based solar cell is up to 31.92% in consideration of the absorption spectrum, 4.52% higher than that of silicon hexagonal nanoconical frustum (SiHNF) arrays. The absorption enhancement of the SiHNH arrays is due to its lower reflectance and more supported guided-mode resonances, and the enhanced ultimate efficiency is insensitive to bottom diameter (D(bot)) of nanoconical hole and the incident angle. The result provides an additional guideline for the nanostructure surface texturing fabrication design for photovoltaic applications.

  2. An artificial solar spectrum substantially alters plant development compared with usual climate room irradiance spectra.

    Science.gov (United States)

    Hogewoning, Sander W; Douwstra, Peter; Trouwborst, Govert; van Ieperen, Wim; Harbinson, Jeremy

    2010-03-01

    Plant responses to the light spectrum under which plants are grown affect their developmental characteristics in a complicated manner. Lamps widely used to provide growth irradiance emit spectra which are very different from natural daylight spectra. Whereas specific responses of plants to a spectrum differing from natural daylight may sometimes be predictable, the overall plant response is generally difficult to predict due to the complicated interaction of the many different responses. So far studies on plant responses to spectra either use no daylight control or, if a natural daylight control is used, it will fluctuate in intensity and spectrum. An artificial solar (AS) spectrum which closely resembles a sunlight spectrum has been engineered, and growth, morphogenesis, and photosynthetic characteristics of cucumber plants grown for 13 d under this spectrum have been compared with their performance under fluorescent tubes (FTs) and a high pressure sodium lamp (HPS). The total dry weight of the AS-grown plants was 2.3 and 1.6 times greater than that of the FT and HPS plants, respectively, and the height of the AS plants was 4-5 times greater. This striking difference appeared to be related to a more efficient light interception by the AS plants, characterized by longer petioles, a greater leaf unfolding rate, and a lower investment in leaf mass relative to leaf area. Photosynthesis per leaf area was not greater for the AS plants. The extreme differences in plant response to the AS spectrum compared with the widely used protected cultivation light sources tested highlights the importance of a more natural spectrum, such as the AS spectrum, if the aim is to produce plants representative of field conditions.

  3. Heating and Acceleration of Solar Wind Ions by Turbulent Wave Spectrum in Inhomogeneous Expanding Plasma

    Science.gov (United States)

    Ofman, Leon; Ozak, Nataly; Vinas, Adolfo F.

    2016-01-01

    Near the Sun (plasma. The heating and the acceleration of the solar wind ions by turbulent wave spectrum in inhomogeneous plasma is studied using a 2.5D hybrid model. The hybrid model describes the kinetics of the ions, while the electrons are modeled as massless neutralizing fluid in an expanding box approach. Turbulent magnetic fluctuations dominated by power-law frequency spectra, which are evident from in-situ as well as remote sensing measurements, are used in our models. The effects of background density inhomogeneity across the magnetic field on the resonant ion heating are studied. The effect of super- Alfvenic ion drift on the ion heating is investigated. It is found that the turbulent wave spectrum of initially parallel propagating waves cascades to oblique modes, and leads to enhanced resonant ion heating due to the inhomogeneity. The acceleration of the solar wind ions is achieved by the parametric instability of large amplitude waves in the spectrum, and is also affected by the inhomogeneity. The results of the study provide the ion temperature anisotropy and drift velocity temporal evolution due to relaxation of the instability. The non-Maxwellian velocity distribution functions (VDFs) of the ions are modeled in the inhomogeneous solar wind plasma in the acceleration region close to the Sun.

  4. Variability of the Magnetic Field Power Spectrum in the Solar Wind at Electron Scales

    Science.gov (United States)

    Roberts, Owen Wyn; Alexandrova, O.; Kajdič, P.; Turc, L.; Perrone, D.; Escoubet, C. P.; Walsh, A.

    2017-12-01

    At electron scales, the power spectrum of solar-wind magnetic fluctuations can be highly variable and the dissipation mechanisms of the magnetic energy into the various particle species is under debate. In this paper, we investigate data from the Cluster mission’s STAFF Search Coil magnetometer when the level of turbulence is sufficiently high that the morphology of the power spectrum at electron scales can be investigated. The Cluster spacecraft sample a disturbed interval of plasma where two streams of solar wind interact. Meanwhile, several discontinuities (coherent structures) are seen in the large-scale magnetic field, while at small scales several intermittent bursts of wave activity (whistler waves) are present. Several different morphologies of the power spectrum can be identified: (1) two power laws separated by a break, (2) an exponential cutoff near the Taylor shifted electron scales, and (3) strong spectral knees at the Taylor shifted electron scales. These different morphologies are investigated by using wavelet coherence, showing that, in this interval, a clear break and strong spectral knees are features that are associated with sporadic quasi parallel propagating whistler waves, even for short times. On the other hand, when no signatures of whistler waves at ∼ 0.1{--}0.2{f}{ce} are present, a clear break is difficult to find and the spectrum is often more characteristic of a power law with an exponential cutoff.

  5. The spectrum of small-scale density fluctuations in the solar wind

    International Nuclear Information System (INIS)

    Readhead, A.C.S.; Kemp, M.C.; Hewish, A.

    1978-01-01

    Interplanetary scintillation observations at frequencies between 74 and 1400 MHz and solar elongations in the range 10 to 90 0 are combined to determine the form of the wavenumber spectrum of electron density fluctuations in the range 10 -3 -1 /km (where k = 2π/lambda). The data are best explained by a spectrum in which there is a genuine scale-length; they are not consistent with a simple power-law spectrum. This suggests that turbulence may be less important than some kind of plasma instability in generating small-scale density fluctuations. The relevance of these conclusions to the use of IPS for determining radio source structure is discussed. (author)

  6. Stability and Change in Diagnosis of Autism Spectrum Disorder Over Time Among Toddlers

    OpenAIRE

    Selvakumar L; Prahbhjot Malhi; Pratibha Singhi

    2018-01-01

    Objective: To assess the diagnostic stability of autism spectrum disorder in children less than three years. Material & Methods: Twenty children (16 boys, 4 girls) with a diagnosis of autistic disorder and Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS) at age of 3 years or less as per DSM IV criteria and who had attained an age of 4 to 5 years were recruited from Pediatric Outpatient services. A Multi-disciplinary evaluation was done at diagnosis and follow up assessmen...

  7. Dual-Function Au@Y2O3:Eu3+ Smart Film for Enhanced Power Conversion Efficiency and Long-Term Stability of Perovskite Solar Cells.

    Science.gov (United States)

    Kim, Chang Woo; Eom, Tae Young; Yang, In Seok; Kim, Byung Su; Lee, Wan In; Kang, Yong Soo; Kang, Young Soo

    2017-07-28

    In the present study, a dual-functional smart film combining the effects of wavelength conversion and amplification of the converted wave by the localized surface plasmon resonance has been investigated for a perovskite solar cell. This dual-functional film, composed of Au nanoparticles coated on the surface of Y 2 O 3 :Eu 3+ phosphor (Au@Y 2 O 3 :Eu 3+ ) nanoparticle monolayer, enhances the solar energy conversion efficiency to electrical energy and long-term stability of photovoltaic cells. Coupling between the Y 2 O 3 :Eu 3+ phosphor monolayer and ultraviolet solar light induces the latter to be converted into visible light with a quantum yield above 80%. Concurrently, the Au nanoparticle monolayer on the phosphor nanoparticle monolayer amplifies the converted visible light by up to 170%. This synergy leads to an increased solar light energy conversion efficiency of perovskite solar cells. Simultaneously, the dual-function film suppresses the photodegradation of perovskite by UV light, resulting in long-term stability. Introducing the hybrid smart Au@Y 2 O 3 :Eu 3+ film in perovskite solar cells increases their overall solar-to-electrical energy conversion efficiency to 16.1% and enhances long-term stability, as compared to the value of 15.2% for standard perovskite solar cells. The synergism between the wavelength conversion effect of the phosphor nanoparticle monolayer and the wave amplification by the localized surface plasmon resonance of the Au nanoparticle monolayer in a perovskite solar cell is comparatively investigated, providing a viable strategy of broadening the solar spectrum utilization.

  8. Neutron spectrum and dose-equivalent in shuttle flights during solar maximum

    Energy Technology Data Exchange (ETDEWEB)

    Keith, J E; Badhwar, G D; Lindstrom, D J [National Aeronautics and Space Administration, Houston, TX (United States). Lyndon B. Johnson Space Center

    1992-01-01

    This paper presents unambiguous measurements of the spectrum of neutrons found in spacecraft during spaceflight. The neutron spectrum was measured from thermal energies to about 10 MeV using a completely passive system of metal foils as neutron detectors. These foils were exposed to the neutron flux bare, covered by thermal neutron absorbers (Gd) and inside moderators (Bonner spheres). This set of detectors was flown on three U.S. Space Shuttle flights, STS-28, STS-36 and STS-31, during the solar maximum. We show that the measurements of the radioactivity of these foils lead to a differential neutron energy spectrum in all three flights that can be represented by a power law, J(E){approx equal}E{sup -0.765} neutrons cm{sup -2} day {sup -1} MeV{sup -1}. We also show that the measurements are even better represented by a linear combination of the terrestrial neutron albedo and a spectrum of neutrons locally produced in a aluminium by protons, computed by a previous author. We use both approximations to the neutron spectrum to produce a worst case and most probable case for the neutron spectra and the resulting dose-equivalents, computed using ICRP-51 neutron fluence-dose conversion tables. We compare these to the skin dose-equivalents due to charged particles during the same flights. (author).

  9. Western Wind and Solar Integration Study Phase 3 – Frequency Response and Transient Stability

    Energy Technology Data Exchange (ETDEWEB)

    Miller, N. W. [GE Energy Management, Schenectady, NY (United States); Shao, M. [GE Energy Management, Schenectady, NY (United States); Pajic, S. [GE Energy Management, Schenectady, NY (United States); D' Aquila, R. [GE Energy Management, Schenectady, NY (United States)

    2014-12-01

    Power system operators and utilities worldwide have concerns about the impact of high-penetration wind and solar generation on electric grid reliability (EirGrid 2011b, Hydro-Quebec 2006, ERCOT 2010). The stability of North American grids under these conditions is a particular concern and possible impediment to reaching future renewable energy goals. Phase 3 of the Western Wind and Solar Integration Study (WWSIS-3) considers a 33% wind and solar annual energy penetration level that results in substantial changes to the characteristics of the bulk power system, including different power flow patterns, different commitment and dispatch of existing synchronous generation, and different dynamic behavior of wind and solar generation. WWSIS-3 evaluates two specific aspects of fundamental frequency system stability: frequency response and transient stability.

  10. Stability considerations and a double-diffusive convection model for solar ponds

    Energy Technology Data Exchange (ETDEWEB)

    Lin, E.I.H.; Sha, W.T.; Soo, S.L.

    1979-04-01

    A brief survey is made on the basic principles, current designs and economic advantages of salinity-gradient solar ponds as solar collectors and reservoirs. Solar ponds are well-suited for various AIPH (agricultural and industrial process heat) applications, and as annual storage devices for space heating and cooling. The benefit of an efficient pond is demonstrated via a preliminary economic analysis which suggests the idea of energy farming as a profitable alternative for land usage in the face of rising fuel cost. The economy and reliability of solar-pond operation depend crucially on the stability of the nonconvective gradient zone against disturbances such as generated by a severe weather condition. Attention is focused on the subject of stability, and pertinent existing results are summarized and discussed. Details of the derivation of three-dimensional stability criteria for thermohaline convection with linear gradients are presented. Ten key questions pertaining to stability are posed, whose answers must be sought through extensive analytical and numerical studies. Possible methods of approach toward enhancing solar-pond stability are also discussed. For the numerical studies of pond behavior and stability characteristics, a double-diffusive convection model is proposed. The model can be constructed by extending the three-dimensional thermohydrodynamic computer code COMMIX-SA, following the necessary steps outlined; computational plans are described. Similarities exist between the halothermocline and the thermocline storage systems, and an extended COMMIX-SA will be a valuable tool for the investigation of both.

  11. Photovoltaic yield: correction method for the mismatch between the solar spectrum and the reference ASTMG AM1.5G spectrum

    Directory of Open Access Journals (Sweden)

    Mambrini Thomas

    2015-01-01

    Full Text Available We propose a method for a spectral correction of the predicted PV yield and we show the importance of the spectral mismatch on the solar cell. Indeed, currently predicted PV yield are made considering solar irradiation, ambient temperature, incidence angle and partially (or not the solar spectrum. However, the solar spectrum is not always the same. It varies depending on the site location, atmospheric conditions, time of the day...This may impact the photovoltaic solar cells differently according to their technology (crystalline Silicon, thin film, multi-junctions... This paper presents a method for calculating the correction of the short-circuit current of a photovoltaic cell due to the mismatch of the solar spectrum with the reference ASTM AM1.5G spectrum, for a specific site, throughout the year, using monthly data of AERONET (AErosol RObotic NETwork established by NASA and CNRS and the model SMARTS (simple model for atmospheric transmission of sunshine developed by the NREL. We applied this correction method on the site of Palaiseau (France, 48.7°N, 2.2°E, 156 m, close to our laboratory, just for comparison and the example of Blida (Algeria, 36°N, 2°E, 230 m is given for one year. This example illustrates the importance of this spectral correction to better estimate the photovoltaic yield. To be more precise, instead of modeling the solar spectral distribution, one can measure it with a spectro-radiometer, and then, derive the spectral mismatch correction. Some of our typical measurements are presented in this paper.

  12. Spectrum

    DEFF Research Database (Denmark)

    Høgfeldt Hansen, Leif

    2016-01-01

    The publication functions as a proces description of the development and construction of an urban furniture SPECTRUM in the city of Gwangju, Republic of Korea. It is used as the cataloque for the exhibition of Spectrum.......The publication functions as a proces description of the development and construction of an urban furniture SPECTRUM in the city of Gwangju, Republic of Korea. It is used as the cataloque for the exhibition of Spectrum....

  13. SOLAR MODULATION OF THE LOCAL INTERSTELLAR SPECTRUM WITH VOYAGER 1 , AMS-02, PAMELA , AND BESS

    Energy Technology Data Exchange (ETDEWEB)

    Corti, C.; Bindi, V.; Consolandi, C.; Whitman, K., E-mail: corti@hawaii.edu [Physics and Astronomy Department, University of Hawaii at Manoa, Honolulu, HI 96822 (United States)

    2016-09-20

    In recent years, the increasing precision of direct cosmic rays measurements opened the door to high-sensitivity indirect searches of dark matter and to more accurate predictions for radiation doses received by astronauts and electronics in space. The key ingredients in the study of these phenomena are the knowledge of the local interstellar spectrum (LIS) of galactic cosmic rays and the understanding of how the solar modulation affects the LIS inside the heliosphere. Voyager 1 , AMS-02, PAMELA , and BESS measurements of proton and helium fluxes provide valuable information, allowing us to shed light on the shape of the LIS and the details of the solar modulation during solar cycles 22-24. A new parametrization of the LIS is presented, based on the latest data from Voyager 1 and AMS-02. Using the framework of the force-field approximation, the solar modulation parameter is extracted from the time-dependent fluxes measured by PAMELA and BESS . A modified version of the force-field approximation with a rigidity-dependent modulation parameter is introduced, yielding better fits than the force-field approximation. The results are compared with the modulation parameter inferred by neutron monitors.

  14. Spacecraft radio scattering observations of the power spectrum of electron density fluctuations in the solar wind

    International Nuclear Information System (INIS)

    Woo, R.; Armstrong, J.W.

    1979-01-01

    Solar wind electron density power spectra in the solar equatorial region are inferred from observations of phase scintillations and spectral broadening made with the Viking, Helios, and Pioneer spacecraft. The heliocentric distance range covered is 2--215 R/sub S/, and for some observations close to the sun the spectra extend to fluctuation frequencies as high as 100 Hz. For heliocentric distances > or approx. =20 R/sub S/ the equivalent spacecraft-measured one-dimensional density spectrym V/sub n/e is well modeled by a single power law (f/sup -alpha/) in the frequency range 10 -4 -5 x 10 -2 Hz. The mean spectral index α is 1.65, very close to the Kolmogorov value of 5/3. Under the assumption of constant solar wind speed, V/sub n/e varies as R/sup -3.45/, where R is heliocentric distance. Within 20 R/sub S/, V/sub n/e can still be modeled by a single power law over the frequency range 10 -3 -10 1 Hz, but the spectral index becomes smaller, αapprox.1.1. The flattening of the density spectrum with 20 R/sub S/ is presumably associated with energy deposition in the near-sun region and acceleration of the solar wind

  15. 宽光谱太阳能电池%Broad-Spectrum Solar Cell

    Institute of Scientific and Technical Information of China (English)

    李承辉; 王锴; 郑玮; 王致祥; 刘建; 游效曾

    2012-01-01

    太阳能电池的光谱响应特性和光电转换效率与光伏材料的微观能带结构及其宏观组装方式密切相关。无论使用哪种光伏材料,普通单结或单层太阳能电池都只能对部分波段的太阳光进行有效利用。宽光谱研究的目标是要使太阳能电池更好地利用太阳光谱所覆盖的全部波段范围的能量,从而提高太阳能电池光电转换效率。本文从化学角度综述了实现宽光谱太阳能电池的基本方法和当前的研究进展,其中包括叠层太阳能电池、中间带太阳能电池、量子点太阳能电池、热光伏太阳能电池、上转换和下转换、分子基柔性太阳能电池等方法。%Due to the energy crisis, utilization of renewable energy sources has been intensively investigated in recent years. Among a variety of renewable energy sources, solar energy is a sustainable alternative option that can be utilized in various ways and can be used for many applications. Converting directly the sunlight to electricity through solar cells is the most common and effective way to use solar energy. The spectral response and overall photo-to-electric energy conversion efficiency of solar cells are closely correlated to the micro band-gap structure and macro assembly process of photovoltaie materials. A solar cell can effectively utilize photons with energy hu close to the semiconductor band gap E,. Photons with energy smaller than the band gap are not absorbed. On the other hand, photons with energy larger than the band gap are absorbed, but the excess energy hu - Eg is not used effectively due to thermalization. Therefore, a normal single junction or single layer solar cell can only use part of the solar radiation no matter what kind of photovoltaic materials are used. Broad-spectrum solar cell aims to use most of the solar energy effectively via several structures or methods: Tandem solar cells, intermediate-band solar cells, quantum dot solar cells

  16. The complete spectrum of the equatorial electrojet related to solar tides: CHAMP observations

    Directory of Open Access Journals (Sweden)

    H. Lühr

    2013-08-01

    Full Text Available Based on 10 yr of magnetic field measurements by the CHAMP satellite we draw a detailed picture of the equatorial electrojet (EEJ tidal variations. For the first time the complete EEJ spectrum related to average solar tides has been compiled. A large fraction of the resulting spectrum is related to the switch on/off of the EEJ between day and night. This effect has carefully been considered when interpreting the results. As expected, largest amplitudes are caused by the migrating tides representing the mean diurnal variation. Higher harmonics of the daily variations show a 1/f fall-off in amplitude. Such a spectrum is required to represent the vanishing of the EEJ current at night. The migrating tidal signal exhibits a distinct annual variation with large amplitudes during December solstice and equinox seasons but a depression by a factor of 1.7 around June–July. A rich spectrum of non-migrating tidal effects is deduced. Most prominent is the four-peaked longitudinal pattern around August. Almost 90% of the structure can be attributed to the diurnal eastward-propagating tide DE3. In addition the westward-propagating DW5 is contributing to wave-4. The second-largest non-migrating tide is the semi-diurnal SW4 around December solstice. It causes a wave-2 feature in satellite observations. The three-peaked longitudinal pattern, often quoted as typical for the December season, is significantly weaker. During the months around May–June a prominent wave-1 feature appears. To first order it represents a stationary planetary wave SPW1 which causes an intensification of the EEJ at western longitudes beyond 60° W and a weakening over Africa/India. In addition, a prominent ter-diurnal non-migrating tide TW4 causes the EEJ to peak later, at hours past 14:00 local time in the western sector. A particularly interesting non-migrating tide is the semi-diurnal SW3. It causes largest EEJ amplitudes from October through December. This tidal component shows a

  17. Vibrational spectrum, ab initio calculations, conformational stabilities and assignment of fundamentals of 1,2-dibromopropane

    Science.gov (United States)

    LaPlante, Arthur J.; Stidham, Howard D.

    2009-10-01

    The mid and far infrared and the Raman spectrum of 1,2-dibromopropane is reported in solid, liquid and gas. Several bands reported by earlier workers are not present in the spectrum of the purified material. Ab initio calculations of optimized geometry, energy, dipole moment, molar volume, vibrational spectrum and normal coordinate calculation were performed using the density functional B3LYP/6-311++g(3df,2pd), and the results used to assist a complete assignment of the 81 fundamental modes of vibrations of the three conformers of 1,2-dibromopropane. Relative energies found conformer A the lowest with G and G' at 815.6 and 871.4 cm -1 higher. The temperature dependence of the Raman spectrum of the liquid was investigated in the CCC bending region and the relative energies determined. It was found that the G' and G conformers lie 236 ± 11 and 327 ±11 cm -1, respectively above the A conformer, leading to the room temperature composition of the liquid as A, 65 ± 1; G', 21 ± 1; G, 14 ± 1%. It is apparent that the calculated highest energy conformer G' is stabilized more than the G conformer in the liquid. The G' conformer has the lowest molar volume effectively changing the interaction distance between conformers in the liquid, and enhancing the effect of its dipole moment.

  18. Thermodynamic Spectrum of Solar Flares Based on SDO/EVE Observations: Techniques and First Results

    Science.gov (United States)

    Wang, Yuming; Zhou, Zhenjun; Zhang, Jie; Liu, Kai; Liu, Rui; Shen, Chenglong; Chamberlin, Phillip C.

    2016-01-01

    The Solar Dynamics Observatory (SDO)/EUV Variability Experiment (EVE) provides rich information on the thermodynamic processes of solar activities, particularly on solar flares. Here, we develop a method to construct thermodynamic spectrum (TDS) charts based on the EVE spectral lines. This tool could potentially be useful for extreme ultraviolet (EUV) astronomy to learn about the eruptive activities on distant astronomical objects. Through several cases, we illustrate what we can learn from the TDS charts. Furthermore, we apply the TDS method to 74 flares equal to or greater than the M5.0 class, and reach the following statistical results. First, EUV peaks are always behind the soft X-ray (SXR) peaks and stronger flares tend to have faster cooling rates. There is a power-law correlation between the peak delay times and the cooling rates, suggesting a coherent cooling process of flares from SXR to EUV emissions. Second, there are two distinct temperature drift patterns, called Type I and Type II. For Type I flares, the enhanced emission drifts from high to low temperature like a quadrilateral, whereas for Type II flares the drift pattern looks like a triangle. Statistical analysis suggests that Type II flares are more impulsive than Type I flares. Third, for late-phase flares, the peak intensity ratio of the late phase to the main phase is roughly correlated with the flare class, and the flares with a strong late phase are all confined. We believe that the re-deposition of the energy carried by a flux rope, which unsuccessfully erupts out, into thermal emissions is responsible for the strong late phase found in a confined flare. Furthermore, we show the signatures of the flare thermodynamic process in the chromosphere and transition region in the TDS charts. These results provide new clues to advance our understanding of the thermodynamic processes of solar flares and associated solar eruptions, e.g., coronal mass ejections.

  19. The Xenon Test Chamber Q-SUN® for testing realistic tolerances of fungi exposed to simulated full spectrum solar radiation.

    Science.gov (United States)

    Dias, Luciana P; Araújo, Claudinéia A S; Pupin, Breno; Ferreira, Paulo C; Braga, Gilberto Ú L; Rangel, Drauzio E N

    2018-06-01

    The low survival of insect-pathogenic fungi when used for insect control in agriculture is mainly due to the deleterious effects of ultraviolet radiation and heat from solar irradiation. In this study, conidia of 15 species of entomopathogenic fungi were exposed to simulated full-spectrum solar radiation emitted by a Xenon Test Chamber Q-SUN XE-3-HC 340S (Q-LAB ® Corporation, Westlake, OH, USA), which very closely simulates full-spectrum solar radiation. A dendrogram obtained from cluster analyses, based on lethal time 50 % and 90 % calculated by Probit analyses, separated the fungi into three clusters: cluster 3 contains species with highest tolerance to simulated full-spectrum solar radiation, included Metarhizium acridum, Cladosporium herbarum, and Trichothecium roseum with LT 50  > 200 min irradiation. Cluster 2 contains eight species with moderate UV tolerance: Aschersonia aleyrodis, Isaria fumosorosea, Mariannaea pruinosa, Metarhizium anisopliae, Metarhizium brunneum, Metarhizium robertsii, Simplicillium lanosoniveum, and Torrubiella homopterorum with LT 50 between 120 and 150 min irradiation. The four species in cluster 1 had the lowest UV tolerance: Lecanicillium aphanocladii, Beauveria bassiana, Tolypocladium cylindrosporum, and Tolypocladium inflatum with LT 50  solar radiation before. We conclude that the equipment provided an excellent tool for testing realistic tolerances of fungi to full-spectrum solar radiation of microbial agents for insect biological control in agriculture. Copyright © 2018 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  20. A generic interface to reduce the efficiency-stability-cost gap of perovskite solar cells

    Science.gov (United States)

    Hou, Yi; Du, Xiaoyan; Scheiner, Simon; McMeekin, David P.; Wang, Zhiping; Li, Ning; Killian, Manuela S.; Chen, Haiwei; Richter, Moses; Levchuk, Ievgen; Schrenker, Nadine; Spiecker, Erdmann; Stubhan, Tobias; Luechinger, Norman A.; Hirsch, Andreas; Schmuki, Patrik; Steinrück, Hans-Peter; Fink, Rainer H.; Halik, Marcus; Snaith, Henry J.; Brabec, Christoph J.

    2017-12-01

    A major bottleneck delaying the further commercialization of thin-film solar cells based on hybrid organohalide lead perovskites is interface loss in state-of-the-art devices. We present a generic interface architecture that combines solution-processed, reliable, and cost-efficient hole-transporting materials without compromising efficiency, stability, or scalability of perovskite solar cells. Tantalum-doped tungsten oxide (Ta-WOx)/conjugated polymer multilayers offer a surprisingly small interface barrier and form quasi-ohmic contacts universally with various scalable conjugated polymers. In a simple device with regular planar architecture and a self-assembled monolayer, Ta-WOx-doped interface-based perovskite solar cells achieve maximum efficiencies of 21.2% and offer more than 1000 hours of light stability. By eliminating additional ionic dopants, these findings open up the entire class of organics as scalable hole-transporting materials for perovskite solar cells.

  1. Early diagnosis of autism spectrum disorder: stability and change in clinical diagnosis and symptom presentation.

    Science.gov (United States)

    Guthrie, Whitney; Swineford, Lauren B; Nottke, Charly; Wetherby, Amy M

    2013-05-01

    Although a diagnosis of autism spectrum disorder (ASD) appears to be stable in children as young as age three, few studies have explored stability of a diagnosis in younger children. Predictive value of diagnostic tools for toddlers and patterns of symptom change are important considerations for clinicians making early diagnoses. Most findings come from high-risk samples, but reports on children screened in community settings are also needed. Stability of diagnosis and Autism Diagnostic Observation Schedule – Toddler Module (ADOS-T) classifications and scores was examined across two time points in a sample of 82 children identified through the FIRST WORDS Project.Children received two comprehensive diagnostic evaluations at average ages of 19.39 (SD = 2.12) and 36.89 (SD = 3.85) months. Stability was 100% when confirming and ruling out a diagnosis of ASD based on a comprehensive diagnostic evaluation that included clinic and home observations,although diagnosis was initially deferred for 17% of the sample. Receiver Operating Characteristic curves revealed excellent sensitivity and acceptable specificity for the ADOS-T compared to concurrent diagnosis. Logistic regressions indicated good predictive value of initial ADOS-T scores for follow-up diagnosis. Finally, both ASD and Non-ASD children demonstrated a decrease in Social Affect scores (i.e.,improvement), whereas children with ASD demonstrated an increase in Restricted and Repetitive Behavior scores (i.e., worsening), changes that were accounted for by nonverbal developmental level in mixed model analyses. Short-term stability was documented for children diagnosed at 19 months on average, although a minority of children initially showed unclear diagnostic presentations.Findings highlight utility of the ADOS-T in making early diagnoses and predicting follow-up diagnoses. Children with ASD demonstrated improvement in social communication behaviors and unfolding of repetitive behaviors, suggesting that certain

  2. Full-spectrum photon management of solar cell structures for photovoltaic–thermoelectric hybrid systems

    International Nuclear Information System (INIS)

    Xu, Yuanpei; Xuan, Yimin; Yang, Lili

    2015-01-01

    Highlights: • A novel photon management method is proposed for hybrid photovoltaic–thermoelectric systems. • Composite structured surfaces enable creditable ultra-broadband anti-reflection property. • Incorporation of anti-reflection and light-trapping brings spectral absorption and transmission. • The efficient photon management of the structured surface is also omnidirectional. - Abstract: In this paper, a novel ultra-broadband photon management structure is proposed for crystalline silicon thin-film solar cells used in the photovoltaic–thermoelectric hybrid system. Nanostructures are employed on both front and back side. Optical behavior of the structure in ultra-broadband (300–2500 nm) are investigated through the Finite Difference Time Domain method. By combing moth-eye and inverted-parabolic surface, a new composite surface structure is proposed for anti-reflection in the ultra-broadband wavelengths. Front metallic nanoparticles, plasmonic back reflector and metallic gratings are studied for light-trapping and the effect of plasmonic back reflector is validated by the experimental data of the external quantum efficiency. The effects of incident angle are discussed for metallic gratings. Numerical computation shows that the incorporation of anti-reflection and light-trapping can obtain high absorption in the solar cell and ensure the rest incident light transmits to the thermoelectric generator efficiently. This work shows potential full-spectrum utilization of solar energy for various photovoltaic devices related with hybrid photovoltaic–thermoelectric systems

  3. Solar Flash Sub-Millimeter Wave Range Spectrum Part Radiation Modeling

    Directory of Open Access Journals (Sweden)

    V. Yu. Shustikov

    2015-01-01

    Full Text Available Currently, solar flares are under observation on the RT-7.5 radio telescope of BMSTU. This telescope operates in a little-studied range of the spectrum, at wavelengths of 3.2 and 2.2 mm (93 and 140 GHz, thereby providing unique information about parameters of the chromosphere plasma and zone of the temperature minimum. Observations on various instruments provided relatively small amount of data on the radio emission flare at frequencies close to 93 GHz, and at frequency of 140 GHz such observations were not carried out. For these reasons, data collected from the RT-7.5 radio telescope are of high value (Shustikov et al., 2012.This work describes modeling and gives interpretation of the reason for raising flux density spectrum of sub-millimeter radio frequency emission using as an example the GOES flare of class M 5.3 occurred on 04.07.2012 in the active region 11515. This flare was observed on the RT-7.5 radio telescope of BMSTU and was described by Shustikov et al. (2012 and by Smirnova et al. (2013, where it has been suggested that the reason for raising radio frequency emission is a bremsstrahlung of the thermal electrons in the hot plasma of the solar chromosphere. Rough estimates of the plasma temperature at the flare source were obtained.This paper proposes model calculations of the flux density spectrum of the sub-millimeter radio emission based on the gyrosynchrotron Fleischman-Kuznetsov code (Fleishman & Kuznetsov, 2010. Section 1 briefly describes observational data, tools and processing methods used in the work. Section 2 shows results of modeling the flare radio emission. Section 3 discusses results and conclusions.Numerical modeling the sub-millimeter part of the spectrum of the radio flux density for the GOES flare of class M5.3 has been carried out. This flare occurred in the active region 11515 on 04.07.2012. Modeling was based on the observations on the BMSTU’s RT-7.5 radio telescope.The paper draws conclusion based on the

  4. CuS/RGO hybrid photocatalyst for full solar spectrum photoreduction from UV/Vis to near-infrared light.

    Science.gov (United States)

    Wu, Jie; Liu, Baibai; Ren, Zhenxing; Ni, Mengying; Li, Can; Gong, Yinyan; Qin, Wei; Huang, Yongli; Sun, Chang Q; Liu, Xinjuan

    2018-05-01

    To make full use of the solar energy, it remains a great challenge for semiconductor photocatalysts to harvest the full solar light spectrum from ultraviolet (UV) to visible even the near infrared (NIR) wavelength. Here we show firstly the CuS/RGO (reduced graphene oxide) hybrid photocatalyst synthesized via a microwave assisted method with full solar light (UV-Vis-NIR) active for efficient Cr(VI) reduction. The CuS/RGO displays high absorption and catalytic activity in the UV, visible and even the NIR light regions. As co-catalyst, RGO can separate and inhibit the recombination of charge carriers, consequently improving the catalytic activity. Only 1wt% RGO emersions can reduce 90% of Cr(VI) under the radiation of light over the full spectrum. Findings may provide a new strategy and substance to expand the utilization range of solar light from UV to visible even the NIR energy. Copyright © 2017. Published by Elsevier Inc.

  5. Adaptive image stabilization of solar observations: A review

    International Nuclear Information System (INIS)

    Von Der Luhe, O.

    1985-01-01

    The purpose of this contribution is to review recent developments of active wave front correction techniques for solar imaging. Experience has shown, that image motion control significantly improves the resolution of typical long exposure applications such as spectrograms and spectroheliograms. Basic IM control systems need only simple technology and, in most cases, are easily implemented in most existing telescopes. Spot trackers are on their way to being routineously used

  6. Solar radiation pressure application for orbital motion stabilization near the Sun-Earth collinear libration point

    Science.gov (United States)

    Polyakhova, Elena; Shmyrov, Alexander; Shmyrov, Vasily

    2018-05-01

    Orbital maneuvering in a neighborhood of the collinear libration point L1 of Sun-Earth system has specific properties, primarily associated with the instability L1. For a long stay in this area of space the stabilization problem of orbital motion requires a solution. Numerical experiments have shown that for stabilization of motion it is requires very small control influence in comparison with the gravitational forces. On the other hand, the stabilization time is quite long - months, and possibly years. This makes it highly desirable to use solar pressure forces. In this paper we illustrate the solar sail possibilities for solving of stabilization problem in a neighborhood L1 with use of the model example.

  7. Stability and Change in Diagnosis of Autism Spectrum Disorder Over Time Among Toddlers

    Directory of Open Access Journals (Sweden)

    Selvakumar L

    2018-03-01

    Full Text Available Objective: To assess the diagnostic stability of autism spectrum disorder in children less than three years. Material & Methods: Twenty children (16 boys, 4 girls with a diagnosis of autistic disorder and Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS at age of 3 years or less as per DSM IV criteria and who had attained an age of 4 to 5 years were recruited from Pediatric Outpatient services. A Multi-disciplinary evaluation was done at diagnosis and follow up assessment was done around 4-5 years of age. Childhood Autism Rating Scale (CARS used to assess symptom severity. Results: At Time 1, at the mean age of 2.4 (SD=4.94 years, 15 (75% children were diagnosed as autistic and 5 (25% children with PDD-NOS. At time 2, at the mean age of 3.9 (SD=9.49 years, 16 (80% children were diagnosed with autism disorder and 2 (10% children were diagnosed with PDD-NOS, and 2 (10% children were found to be off the ASD spectrum. Looking at specific ASD diagnosis, the diagnostic stability of an Autistic Disorder was 12/15 (80% and PDD-NOS was 0/5 (0%. Only 2 children went off the spectrum and 4 children developed the full symptoms at Time 2. Conclusion: The present study supports that a reliable diagnosis of autism can be made in children which would stand over time provided that expert clinicians are available. However, continued work is needed for the development of reliable and valid diagnostic tools.

  8. Mg I absorption features in the solar spectrum near 9 and 12 microns

    Science.gov (United States)

    Glenar, David A.; Reuter, Dennis C.; Deming, Drake; Chang, Edward S.

    1988-01-01

    High-resolution FTS observations from the Kitt Peak National Solar Observatory and the Spacelab 3 ATMOS experiment have revealed additional infrared transitions due to Mg I in the spectra of both quiet sun and sunspot penumbra. In contrast to previous observations, these transitions are seen in absorption, not emission. Absorption intensities range from 1 to 7 percent of the continuum in the quiet sun. In the penumbra, the same features appear to show Zeeman splitting. Modeling of the line profiles in the photospheric spectrum shows evidence for a factor of three overabundance in the n = 5 or more levels of Mg I in the upper photosphere, but with no deviations from a Planck source function. It is concluded that whatever the process that produces the emission (including the Lemke and Holweger mechanism), it must occur well above the tau(5000) = 0.01 level.

  9. Superior stability for perovskite solar cells with 20% efficiency using vacuum co-evaporation.

    Science.gov (United States)

    Zhu, Xuejie; Yang, Dong; Yang, Ruixia; Yang, Bin; Yang, Zhou; Ren, Xiaodong; Zhang, Jian; Niu, Jinzhi; Feng, Jiangshan; Liu, Shengzhong Frank

    2017-08-31

    Chemical composition and film quality are two key figures of merit for large-area high-efficiency perovskite solar cells. To date, all studies on mixed perovskites have used solution-processing, which results in imperfect surface coverage and pin-holes generated during solvent evaporation, execrably influencing the stability and efficiency of perovskite solar cells. Herein, we report our development using a vacuum co-evaporation deposition method to fabricate pin-hole-free cesium (Cs)-substituted perovskite films with complete surface coverage. Apart from the simplified procedure, the present method also promises tunable band gap, reduced trap-state density and longer carrier lifetime, leading to solar cell efficiency as high as 20.13%, which is among the highest reported for planar perovskite solar cells. The splendid performance is attributed to superior merits of the Cs-substituted perovskite film including tunable band gap, reduced trap-state density and longer carrier lifetime. Moreover, the Cs-substituted perovskite device without encapsulation exhibits significantly higher stability in ambient air compared with the single-component counterpart. When the Cs-substituted perovskite solar cells are stored in dark for one year, the PCE remains at 19.25%, degrading only 4.37% of the initial efficiency. The excellent stability originates from reduced lattice constant and relaxed strain in perovskite lattice by incorporating Cs cations into the crystal lattice, as demonstrated by the positive peak shifts and reduced peak width in X-ray diffraction analysis.

  10. Mechanical stability of roll-to-roll printed solar cells under cyclic bending and torsion

    DEFF Research Database (Denmark)

    Finn, Mickey; Martens, Christian James; Zaretski, Aliaksandr V.

    2018-01-01

    The ability of printed organic solar cells (OSCs) to survive repeated mechanical deformation is critical to large-scale implementation. This paper reports an investigation into the mechanical stability of OSCs through bending and torsion testing of whole printed modules. Two types of modules...

  11. Stability studies and degradation analysis of plastic solar cell materials by FTIR spectroscopy

    NARCIS (Netherlands)

    Neugebauer, H.; Brabec, C.J.; Hummelen, J.C.; Janssen, R.A.J.; Sariciftci, N.S.

    1999-01-01

    Results of controlled degradation experiments performed with the individual components and with the actual mixture used in plastic solar cells are shown. A testing procedure for the stability and for degradation effects under illumination in controlled atmosphere using FTIR-ATR spectroscopy is

  12. Recent Advances in Heliogyro Solar Sail Structural Dynamics, Stability, and Control Research

    Science.gov (United States)

    Wilkie, W. Keats; Warren, Jerry E.; Horta, Lucas G.; Lyle, Karen H.; Juang, Jer-Nan; Gibbs, S. Chad; Dowell, Earl H.; Guerrant, Daniel V.; Lawrence, Dale

    2015-01-01

    Results from recent NASA sponsored research on the structural dynamics, stability, and control characteristics of heliogyro solar sails are summarized. Specific areas under investigation include coupled nonlinear finite element analysis of heliogyro membrane blade with solar radiation pressure effects, system identification of spinning membrane structures, and solarelastic stability analysis of heliogyro solar sails, including stability during blade deployment. Recent results from terrestrial 1-g blade dynamics and control experiments on "rope ladder" membrane blade analogs, and small-scale in vacuo system identification experiments with hanging and spinning high-aspect ratio membranes will also be presented. A low-cost, rideshare payload heliogyro technology demonstration mission concept is used as a mission context for these heliogyro structural dynamics and solarelasticity investigations, and is also described. Blade torsional dynamic response and control are also shown to be significantly improved through the use of edge stiffening structural features or inclusion of modest tip masses to increase centrifugal stiffening of the blade structure. An output-only system identification procedure suitable for on-orbit blade dynamics investigations is also developed and validated using ground tests of spinning sub-scale heliogyro blade models. Overall, analytical and experimental investigations to date indicate no intractable stability or control issues for the heliogyro solar sail concept.

  13. Stability of organic molecules against shocks in the young Solar nebula

    NARCIS (Netherlands)

    Kamp, Inga; Milosavljevic, Milica; Stempels, E

    2009-01-01

    One of the fundamental astrobiology questions is how life has formed in our Solar System. In this context the formation and stability of abiotic organic molecules such as CH(4), formic acid and amino acids, is important for understanding how organic material has formed and survived shocks and

  14. Thermal Stability-Enhanced and High-Efficiency Planar Perovskite Solar Cells with Interface Passivation.

    Science.gov (United States)

    Zhang, Weihai; Xiong, Juan; Jiang, Li; Wang, Jianying; Mei, Tao; Wang, Xianbao; Gu, Haoshuang; Daoud, Walid A; Li, Jinhua

    2017-11-08

    As the electron transport layer (ETL) of perovskite solar cells, oxide semiconductor zinc oxide (ZnO) has been attracting great attention due to its relatively high mobility, optical transparency, low-temperature fabrication, and good environment stability. However, the nature of ZnO will react with the patron on methylamine, which would deteriorate the performance of cells. Although many methods, including high-temperature annealing, doping, and surface modification, have been studied to improve the efficiency and stability of perovskite solar cells with ZnO ETL, devices remain relatively low in efficiency and stability. Herein, we adopted a novel multistep annealing method to deposit a porous PbI 2 film and improved the quality and uniformity of perovskite films. The cells with ZnO ETL were fabricated at the temperature of perovskite film. Interestingly, the PCE of PCBM-passivated cells could reach nearly 19.1%. To our best knowledge, this is the highest PCE value of ZnO-based perovskite solar cells until now. More importantly, PCBM modification could effectively suppress the decomposition of MAPbI 3 and improve the thermal stability of cells. Therefore, the ZnO is a promising candidate of electron transport material for perovskite solar cells in future applications.

  15. THERMODYNAMIC SPECTRUM OF SOLAR FLARES BASED ON SDO/EVE OBSERVATIONS: TECHNIQUES AND FIRST RESULTS

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yuming; Zhou, Zhenjun; Liu, Kai; Liu, Rui; Shen, Chenglong [CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhang, Jie [School of Physics, Astronomy and Computational Sciences, George Mason University, 4400 University Drive, MSN 6A2, Fairfax, VA 22030 (United States); Chamberlin, Phillip C., E-mail: ymwang@ustc.edu.cn [Solar Physics Laboratory, Heliophysics Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2016-03-15

    The Solar Dynamics Observatory (SDO)/EUV Variability Experiment (EVE) provides rich information on the thermodynamic processes of solar activities, particularly on solar flares. Here, we develop a method to construct thermodynamic spectrum (TDS) charts based on the EVE spectral lines. This tool could potentially be useful for extreme ultraviolet (EUV) astronomy to learn about the eruptive activities on distant astronomical objects. Through several cases, we illustrate what we can learn from the TDS charts. Furthermore, we apply the TDS method to 74 flares equal to or greater than the M5.0 class, and reach the following statistical results. First, EUV peaks are always behind the soft X-ray (SXR) peaks and stronger flares tend to have faster cooling rates. There is a power-law correlation between the peak delay times and the cooling rates, suggesting a coherent cooling process of flares from SXR to EUV emissions. Second, there are two distinct temperature drift patterns, called Type I and Type II. For Type I flares, the enhanced emission drifts from high to low temperature like a quadrilateral, whereas for Type II flares the drift pattern looks like a triangle. Statistical analysis suggests that Type II flares are more impulsive than Type I flares. Third, for late-phase flares, the peak intensity ratio of the late phase to the main phase is roughly correlated with the flare class, and the flares with a strong late phase are all confined. We believe that the re-deposition of the energy carried by a flux rope, which unsuccessfully erupts out, into thermal emissions is responsible for the strong late phase found in a confined flare. Furthermore, we show the signatures of the flare thermodynamic process in the chromosphere and transition region in the TDS charts. These results provide new clues to advance our understanding of the thermodynamic processes of solar flares and associated solar eruptions, e.g., coronal mass ejections.

  16. Photochemical stability of π-conjugated polymers for polymer solar cells: a rule of thumb

    DEFF Research Database (Denmark)

    Manceau, Matthieu; Bundgaard, Eva; Carlé, Jon Eggert

    2011-01-01

    A comparative photochemical stability study of a wide range of π-conjugated polymers relevant to polymer solar cells is presented. The behavior of each material has been investigated under simulated sunlight (1 sun, 1000 W m−2, AM 1.5G) and ambient atmosphere. Degradation was monitored during age...... ageing combining UV-visible and infrared spectroscopies. From the comparison of the collected data, the influence of the polymer chemical structure on its stability has been discussed. General rules relative to the polymer structure–stability relationship are proposed....

  17. Statistical Analysis of Solar PV Power Frequency Spectrum for Optimal Employment of Building Loads

    Energy Technology Data Exchange (ETDEWEB)

    Olama, Mohammed M [ORNL; Sharma, Isha [ORNL; Kuruganti, Teja [ORNL; Fugate, David L [ORNL

    2017-01-01

    In this paper, a statistical analysis of the frequency spectrum of solar photovoltaic (PV) power output is conducted. This analysis quantifies the frequency content that can be used for purposes such as developing optimal employment of building loads and distributed energy resources. One year of solar PV power output data was collected and analyzed using one-second resolution to find ideal bounds and levels for the different frequency components. The annual, seasonal, and monthly statistics of the PV frequency content are computed and illustrated in boxplot format. To examine the compatibility of building loads for PV consumption, a spectral analysis of building loads such as Heating, Ventilation and Air-Conditioning (HVAC) units and water heaters was performed. This defined the bandwidth over which these devices can operate. Results show that nearly all of the PV output (about 98%) is contained within frequencies lower than 1 mHz (equivalent to ~15 min), which is compatible for consumption with local building loads such as HVAC units and water heaters. Medium frequencies in the range of ~15 min to ~1 min are likely to be suitable for consumption by fan equipment of variable air volume HVAC systems that have time constants in the range of few seconds to few minutes. This study indicates that most of the PV generation can be consumed by building loads with the help of proper control strategies, thereby reducing impact on the grid and the size of storage systems.

  18. Stability of electric characteristics of solar cells for continuous power supply

    Directory of Open Access Journals (Sweden)

    Stojanović Nebojša M.

    2015-01-01

    Full Text Available This paper investigates the output characteristics of photovoltaic solar cells working in hostile working conditions. Examined cells, produced by different innovative procedures, are available in the market. The goal was to investigate stability of electric characteristics of solar cells, which are used today in photovoltaic solar modules for charging rechargeable batteries which, coupled with batteries, supply various electronic systems such as radio repeaters on mountains tops, airplanes, mobile communication stations and other remote facilities. Charging of rechargeable batteries requires up to 25 % higher voltage compared to nominal output voltage of the battery. This paper presents results of research of solar cells, which also apply to cases in which continuous power supply is required. [Projekat Ministarstva nauke Republike Srbije, br. III 171007

  19. The nekhoroshev theorem and long-term stabilities in the solar system

    Directory of Open Access Journals (Sweden)

    Guzzo M.

    2015-01-01

    Full Text Available The Nekhoroshev theorem has been often indicated in the last decades as the reference theorem for explaining the dynamics of several systems which are stable in the long-term. The Solar System dynamics provides a wide range of possible and useful applications. In fact, despite the complicated models which are used to numerically integrate realistic Solar System dynamics as accurately as possible, when the integrated solutions are chaotic the reliability of the numerical integrations is limited, and a theoretical long-term stability analysis is required. After the first formulation of Nekhoroshev’s theorem in 1977, many theoretical improvements have been achieved. On the one hand, alternative proofs of the theorem itself led to consistent improvements of the stability estimates; on the other hand, the extensions which were necessary to apply the theorem to the systems of interest for Solar System Dynamics, in particular concerning the removal of degeneracies and the implementation of computer assisted proofs, have been developed. In this review paper we discuss some of the motivations and the results which have made Nekhoroshev’s theorem a reference stability result for many applications in the Solar System dynamics.

  20. Hydrophobic Polystyrene Passivation Layer for Simultaneously Improved Efficiency and Stability in Perovskite Solar Cells.

    Science.gov (United States)

    Li, Minghua; Yan, Xiaoqin; Kang, Zhuo; Huan, Yahuan; Li, Yong; Zhang, Ruxiao; Zhang, Yue

    2018-06-06

    The major restraint for the commercialization of the high-performance hybrid metal halide perovskite solar cells is the long-term stability, especially at the infirm interface between the perovskite film and organic charge-transfer layer. Recently, engineering the interface between the perovskite and spiro-OMeTAD becomes an effective strategy to simultaneously improve the efficiency and stability in the perovskite solar cells. In this work, we demonstrated that introducing an interfacial polystyrene layer between the perovskite film and spiro-OMeTAD layer can effectively improve the perovskite solar cells photovoltaic performance. The inserted polystyrene layer can passivate the interface traps and defects effectively and decrease the nonradiative recombination, leading to enhanced photoluminescence intensity and carrier lifetime, without compromising the carrier extraction and transfer. Under the optimized condition, the perovskite solar cells with the polystyrene layer achieve an enhanced average power efficiency of about 19.61% (20.46% of the best efficiency) from about 17.63% with negligible current density-voltage hysteresis. Moreover, the optimized perovskite solar cells with the hydrophobic polystyrene layer can maintain about 85% initial efficiency after 2 months storage in open air conditions without encapsulation.

  1. Degradation and stability of R2R manufactured polymer solar cells

    DEFF Research Database (Denmark)

    Norrman, Kion; Krebs, Frederik C

    2009-01-01

    Polymer solar cells have many advantages such as light weight, flexibility, environmental friendliness, low thermal budget, low cost and most notably very fast modes of production by printing techniques. Production experiments have shown that it is highly feasible with existing technology to mass...... produce polymer solar cells at a very low cost. We have employed state-of-the-art analytical techniques to address the challenging issues of degradation and stability of R2R manufactured devices. We have specifically studied the relative effect of oxygen and water on the operational devices in regard...

  2. Adaptive Full-Spectrum Solar Energy Systems Cross-Cutting R&D on adaptive full-spectrum solar energy systems for more efficient and affordable use of solar energy in buildings and hybrid photobioreactors

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Byard; Kim, Kwang

    2006-03-30

    This RD&D project is a multi-institutional effort to develop a hybrid solar lighting (HSL) system that transports daylight from a paraboloidal dish concentrator to a luminaire via a bundle of polymer fiber optics. The luminaire can be a device to distribute sunlight into a space for the production of algae for CO{sub 2} sequestration or it can be a device that is a combination of daylighting and electric lighting for space/task lighting. In this project, the sunlight is collected using a one-meter paraboloidal concentrator dish with two-axis tracking. For the third generation (beta) system, the secondary mirror is an ellipsoidal mirror that directs the visible light into a bundle of 3 mm diameter fibers. The IR spectrum is filtered out to minimize unnecessary heating at the fiber entrance region. This report describes the major achievements from this research that began in August 2001.

  3. ADAPTIVE FULL-SPECTRUM SOLAR ENERGY SYSTEMS Cross-Cutting R & D on adaptive full-spectrum solar energy systems for more efficient and affordable use of solar energy in buildings and hybrid photobioreactors

    Energy Technology Data Exchange (ETDEWEB)

    Byard D. Wood; David L. Beshears

    2006-02-01

    This RD&D project is a three year team effort to develop a hybrid solar lighting (HSL) system that transports daylight from a paraboloidal dish concentrator to a luminaire via a bundle of polymer fiber optics. The luminaire can be a device to distribute sunlight into a space for the production of algae or it can be a device that is a combination of daylighting and electric lighting for space/task lighting. In this project, the sunlight is collected using a one-meter paraboloidal concentrator dish with two-axis tracking. For the third generation (beta) system, the secondary mirror is an ellipsoidal mirror that directs the visible light into a bundle of 3 mm diameter fibers. The IR spectrum is filtered out to minimize unnecessary heating at the fiber entrance region. This report describes the following investigations: Niche applications for HSL technology, Luminaire design characteristics for linear and point lighting fixtures, and Daylight affects on productivity.

  4. ADAPTIVE FULL-SPECTRUM SOLAR ENERGY SYSTEMS CROSS-CUTTING R&D ON ADAPTIVE FULL-SPECTRUM SOLAR ENERGY SYSTEMS FOR MORE EFFICIENT AND AFFORDABLE USE OF SOLAR ENERGY IN BUILDINGS AND HYBRID PHOTOBIOREACTORS

    Energy Technology Data Exchange (ETDEWEB)

    Byard D. Wood; Jeff D. Muhs

    2004-08-01

    This RD&D project is a three year team effort to develop a hybrid solar lighting (HSL) system that transports daylight from a paraboloidal dish concentrator to a luminaire via a bundle of small core or a large core polymer fiber optics. The luminaire can be a device to distribute sunlight into a space for the production of algae or it can be a device that is a combination of daylighting and electric lighting for space/task lighting. In this project, the sunlight is collected using a one-meter paraboloidal concentrator dish with two-axis tracking. For the second generation (alpha) system, the secondary mirror is an ellipsoidal mirror that directs the visible light into a bundle of small-core fibers. The IR spectrum is filtered out to minimize unnecessary heating at the fiber entrance region. This report describes the following investigations of various aspects of the system. Taken as a whole, they confirm significant progress towards the technical feasibility and commercial viability of this technology. (1) TRNSYS Modeling of a Hybrid Lighting System: Building Energy Loads and Chromaticity Analysis; (2) High Lumens Screening Test Setup for Optical Fibers; (3) Photo-Induced Heating in Plastic Optical Fiber Bundles; (4) Low-Cost Primary Mirror Development; (5) Potential Applications for Hybrid Solar Lighting; (6) Photobioreactor Population Experiments and Productivity Measurements; and (7) Development of a Microalgal CO2-Biofixation Photobioreactor.

  5. The UV-A and visible solar irradiance spectrum: inter-comparison of absolutely calibrated, spectrally medium resolution solar irradiance spectra from balloon- and satellite-borne measurements

    Directory of Open Access Journals (Sweden)

    W. Gurlit

    2005-01-01

    Full Text Available Within the framework of the ENVISAT/-SCIAMACHY satellite validation, solar irradiance spectra are absolutely measured at moderate resolution in the UV/visible spectral range (in the UV from 316.7-418 nm and the visible from 400-652 nm at a full width half maximum resolution of 0.55 nm and 1.48 nm, respectively from aboard the azimuth-controlled LPMA/DOAS balloon gondola at around 32 km balloon float altitude. After accounting for the atmospheric extinction due to Rayleigh scattering and gaseous absorption (O3 and NO2, the measured solar spectra are compared with previous observations. Our solar irradiance spectrum perfectly agrees within +0.03% with the re-calibrated Kurucz et al. (1984 solar spectrum (Fontenla et al., 1999, called MODTRAN 3.7 in the visible spectral range (415-650 nm, but it is +2.1% larger in the (370-415 nm wavelength interval, and -4% smaller in the UV-A spectral range (316.7-370 nm, when the Kurucz spectrum is convolved to the spectral resolution of our instrument. Similar comparisons of the SOLSPEC (Thuillier et al., 1997, 1998a, b and SORCE/SIM (Harder et al., 2000 solar spectra with MODTRAN 3.7 confirms our findings with the values being -0.5%, +2%, and -1.4% for SOLSPEC -0.33%, -0.47%, and -6.2% for SORCE/SIM, respectively. Comparison of the SCIAMACHY solar spectrum from channels 1 to 4 (- re-calibrated by the University of Bremen - with MODTRAN 3.7 indicates an agreement within -0.4% in the visible spectral range (415-585 nm, -1.6% within the 370-415 nm, and -5.7% within 325-370 nm wavelength interval, in agreement with the results of the other sensors. In agreement with findings of Skupin et al. (2002 our study emphasizes that the present ESA SCIAMACHY level 1 calibration is systematically +15% larger in the considered wavelength intervals when compared to all available other solar irradiance measurements.

  6. ADAPTIVE FULL-SPECTRUM SOLAR ENERGY SYSTEMS CROSS-CUTTING R&D ON ADAPTIVE FULL-SPECTRUM SOLAR ENERGY SYSTEMS FOR MORE EFFICIENT AND AFFORDABLE USE OF SOLAR ENERGY IN BUILDINGS AND HYBRID PHOTOBIOREACTORS

    Energy Technology Data Exchange (ETDEWEB)

    Byard D. Wood; Jeff D. Muhs

    2002-09-01

    This RD&D project is a three year team effort to develop a hybrid solar lighting (HSL) system that transports day light from a paraboloidal dish concentrator to a luminaire via a large core polymer fiber optic. The luminaire can be a device to distribute sunlight into a space for the production of algae or it can be a device that is a combination of day lighting and fluorescent lighting for office lighting. In this project, the sunlight is collected using a one-meter paraboloidal concentrator dish with two-axis tracking. The secondary mirror consists of eight planar-segmented mirrors that direct the visible part of the spectrum to eight fibers (receiver) and subsequently to eight luminaires. This results in about 8,200 lumens incident at each fiber tip. Each fiber can illuminate about 16.7 m{sup 2} (180 ft{sup 2}) of office space. The IR spectrum is directed to a thermophotovoltaic array to produce electricity. This report describes eleven investigations on various aspects of the system. Taken as a whole, they confirm the technical feasibility of this technology.

  7. Analysis to long-term stability of solar cables; Untersuchungen zur Langzeitstabilitaet von Solarleitungen

    Energy Technology Data Exchange (ETDEWEB)

    Funtan, P.

    2005-07-01

    For the moment it is not possible to say anything about the long-term stability of solar cables. Own experiences shows, that the rubber solar cable H07 RN-F (of one manufacturer) is not qualified for installations, longer than 10 years. The outer isolation of the cable first shows embrittlements and later deep cracks. Microscopically analysis confirms this. Measurements of temperature in typical installation areas of solar cables also shows, that the influence of temperature, regarding aging plays not the most important role, when the cable is installed in a sun protected position. Up to now the reason of the cable destruction is not definitely clarified. Chemically analysis of a damaged and an intact part of the cable, which was installed inside of a module junction box (reduced humility), shows no differences in the chemical consistence. It seems, that it is a combinated effect of temperature and humidity. Further analysis will be performed. (orig.)

  8. How different are the Liège and Hamburg atlases of the solar spectrum?

    Science.gov (United States)

    Doerr, H.-P.; Vitas, N.; Fabbian, D.

    2016-05-01

    Context. The high-fidelity solar spectral atlas prepared by http://adsabs.harvard.edu/abs/1973apds.book.....D Delbouille et al. (Liège atlas, 1973) and the atlas by http://adsabs.harvard.edu/abs/1999SoPh..184..421N Neckel (Hamburg atlas, 1999, Sol. Phys., 184, 421) are widely recognised as the most important collection of reference spectra of the Sun at disc centre in the visible wavelength range. The two datasets serve as fundamental resources for many researchers, in particular for chemical abundance analyses. But despite their similar published specifications (spectral resolution and noise level), the shapes of the spectral lines in the two atlases differ significantly and systematically. Aims: Knowledge of any instrumental degradations is imperative to fully exploit the information content of spectroscopic data. We seek to investigate the magnitude of these differences and explain the possible sources. We provide the wavelength-dependent correction parameters that need to be taken into account when the spectra are to be compared with synthetic data, for instance. Methods: A parametrically degraded version of the Hamburg spectrum was fitted to the Liège spectrum. The parameters of the model (wavelength shift, broadening, intensity scaling, and intensity offset) represent the different characteristics of the respective instruments, observational strategies, and data processing. Results: The wavelength scales of the Liège and Hamburg atlases differ on average by 0.5 mÅ with a standard deviation of ± 2 mÅ, except for a peculiar region around 5500 Å. The continuum levels are offset by up to 18% below 5000 Å, but remain stably at a 0.8% difference towards the red. We find no evidence for spectral stray light in the Liège spectrum. Its resolving power is almost independent of wavelength but limited to about 216 000, which is between two to six times lower than specified. When accounting for the degradations determined in this work, the spectra of the two

  9. Regional Climate Impacts of Stabilizing Global Warming at 1.5 K Using Solar Geoengineering

    Science.gov (United States)

    Jones, Anthony C.; Hawcroft, Matthew K.; Haywood, James M.; Jones, Andy; Guo, Xiaoran; Moore, John C.

    2018-02-01

    The 2015 Paris Agreement aims to limit global warming to well below 2 K above preindustrial levels, and to pursue efforts to limit global warming to 1.5 K, in order to avert dangerous climate change. However, current greenhouse gas emissions targets are more compatible with scenarios exhibiting end-of-century global warming of 2.6-3.1 K, in clear contradiction to the 1.5 K target. In this study, we use a global climate model to investigate the climatic impacts of using solar geoengineering by stratospheric aerosol injection to stabilize global-mean temperature at 1.5 K for the duration of the 21st century against three scenarios spanning the range of plausible greenhouse gas mitigation pathways (RCP2.6, RCP4.5, and RCP8.5). In addition to stabilizing global mean temperature and offsetting both Arctic sea-ice loss and thermosteric sea-level rise, we find that solar geoengineering could effectively counteract enhancements to the frequency of extreme storms in the North Atlantic and heatwaves in Europe, but would be less effective at counteracting hydrological changes in the Amazon basin and North Atlantic storm track displacement. In summary, solar geoengineering may reduce global mean impacts but is an imperfect solution at the regional level, where the effects of climate change are experienced. Our results should galvanize research into the regionality of climate responses to solar geoengineering.

  10. Measurement of Cosmic-Ray Antiproton Spectrum at Solar Minimum with a Long-Duration Balloon Flight in Antarctica

    Science.gov (United States)

    Abe, K.; Fuke, H.; Haino, S.; Hams, T.; Hasegawa, M.; Horikoshi, A.; Kim, K. C.; Kusumoto, A.; Lee, M. H.; Makida, Y.; hide

    2011-01-01

    The energy spectrum of cosmic-ray antiprotons (p(raised bar)'s) collected by the BESS-Polar II instrument during a long-duration flight over Antarctica in the solar minimum period of December 2007 through January 2008. The p(raised bar) spectrum measured by BESS-Polar II shows good consistency with secondary p(raised bar) calculations. Cosmologically primary p(raised bar)'s have been searched for by comparing the observed and calculated p(raised bar) spectra. The BESSPolar II result shows no evidence of primary p(raised bar)'s originating from the evaporation of PBH.

  11. Solar neutrino spectrum, sterile neutrinos and additional radiation in the Universe

    International Nuclear Information System (INIS)

    Holanda, Pedro Cunha de

    2011-01-01

    Full text: Recent results from the SNO, Super-Kamiokande and Borexino experiments do not show the expected upturn of the energy spectrum of events (the ratio R ≡ N obs /N SSM ) at low energies. At the same time, cosmological observations testify for possible existence of additional relativistic degrees of freedom in the early Universe: ΔN eff = 1 - 2. These facts strengthen the case of very light sterile neutrino, ν s , with Δm 0 1 2 ∼ (0.7 - 2) . 10 -5 e V 2 , which mixes weakly with the active neutrinos. The ν s mixing in the mass eigenstate ν 1 characterized by sin 2 2∝ ∼ 10 -3 can explain an absence of the upturn. The mixing of ν s in the eigenstate ν 3 with sin 2 β ∼ 0.1 leads to production of ν s via oscillations in the Universe and to additional contribution Δ N eff ∼ 0.7 -1 before the big bang nucleosynthesis and later. Such a mixing can be tested in forthcoming experiments with the atmospheric neutrinos as well as in future accelerator long baseline experiments. It has substantial impact on conversion of the supernova neutrinos. We perform a qualitative and quantitative analysis of solar neutrino data including a fourth neutrino with different mixings with the active neutrino sector.(author)

  12. Research Update: Strategies for improving the stability of perovskite solar cells

    Directory of Open Access Journals (Sweden)

    Severin N. Habisreutinger

    2016-09-01

    Full Text Available The power-conversion efficiency of perovskite solar cells has soared up to 22.1% earlier this year. Within merely five years, the perovskite solar cell can now compete on efficiency with inorganic thin-film technologies, making it the most promising of the new, emerging photovoltaic solar cell technologies. The next grand challenge is now the aspect of stability. The hydrophilicity and volatility of the organic methylammonium makes the work-horse material methylammonium lead iodide vulnerable to degradation through humidity and heat. Additionally, ultraviolet radiation and oxygen constitute stressors which can deteriorate the device performance. There are two fundamental strategies to increasing the device stability: developing protective layers around the vulnerable perovskite absorber and developing a more resilient perovskite absorber. The most important reports in literature are summarized and analyzed here, letting us conclude that any long-term stability, on par with that of inorganic thin-film technologies, is only possible with a more resilient perovskite incorporated in a highly protective device design.

  13. Model and analysis of solar thermal generators to reduce the intermittency of photovoltaic systems with the use of spectrum splitting

    Science.gov (United States)

    Ayala, Silvana; Wu, Yuechen; Vorndran, Shelby; Santiago, Raphael P.; Kostuk, Raymond K.

    2015-09-01

    In this paper we introduce an approach to damping intermittency in photovoltaic (PV) system output due to fluctuations in solar illumination generated by use of a hybrid PV-thermal electric (TE) generation system. We describe the necessary constrains of the PV-TE system based on its thermodynamic characteristics. The basis for the approach is that the thermal time constant for the TE device is much longer than that of a PV cell. When used in combination with an optimized thermal storage device short periods of intermittency (several minutes) in PV output due to passing clouds can be compensated. A comparison of different spectrum splitting systems to efficiently utilize the incident solar spectrum between the PV and TE converters are also examined. The time-dependent behavior of a hybrid PV-TE converter with a thermal storage element is computed with SMARTS modeled irradiance data and compared to real weather and irradiation conditions for Tucson, Arizona.

  14. Experimental analysis and modeling of the IV characteristics of photovoltaic solar cells under solar spectrum spot illumination

    Energy Technology Data Exchange (ETDEWEB)

    Munji, M.K., E-mail: mathew.munji@nmmu.ac.z [Department of Physics, Nelson Mandela Metropolitan University, PO Box 7700 Port Elizabeth 6031 (South Africa); Dyk, E.E. van; Vorster, F.J. [Department of Physics, Nelson Mandela Metropolitan University, PO Box 7700 Port Elizabeth 6031 (South Africa)

    2009-12-01

    In this paper, some models that have been put forward to explain the characteristics of a photovoltaic solar cell device under solar spot-illumination are investigated. In the experimental procedure, small areas of the cell were selected and illuminated at different solar intensities. The solar cell open circuit voltage (V{sub oc}) and short circuit current (I{sub sc}) obtained at different illumination intensities was used to determine the solar cell ideality factor. By varying the illuminated area on the solar cell, changes in the ideality factor were studied. The ideality factor obtained increases with decreasing illumination surface ratio. The photo-generated current at the illuminated part of the cell is assumed to act as a dc source that injects charge carriers into the p-n junction of the whole solar cell while the dark region of the solar cell operates in a low space charge recombination regime with small diffusion currents. From this analysis, a different model of a spot illuminated cell that uses the variation of ideality factor with the illuminated area is proposed.

  15. Experimental analysis and modeling of the IV characteristics of photovoltaic solar cells under solar spectrum spot illumination

    International Nuclear Information System (INIS)

    Munji, M.K.; Dyk, E.E. van; Vorster, F.J.

    2009-01-01

    In this paper, some models that have been put forward to explain the characteristics of a photovoltaic solar cell device under solar spot-illumination are investigated. In the experimental procedure, small areas of the cell were selected and illuminated at different solar intensities. The solar cell open circuit voltage (V oc ) and short circuit current (I sc ) obtained at different illumination intensities was used to determine the solar cell ideality factor. By varying the illuminated area on the solar cell, changes in the ideality factor were studied. The ideality factor obtained increases with decreasing illumination surface ratio. The photo-generated current at the illuminated part of the cell is assumed to act as a dc source that injects charge carriers into the p-n junction of the whole solar cell while the dark region of the solar cell operates in a low space charge recombination regime with small diffusion currents. From this analysis, a different model of a spot illuminated cell that uses the variation of ideality factor with the illuminated area is proposed.

  16. Composition-graded nanowire solar cells fabricated in a single process for spectrum-splitting photovoltaic systems.

    Science.gov (United States)

    Caselli, Derek; Liu, Zhicheng; Shelhammer, David; Ning, Cun-Zheng

    2014-10-08

    Nanomaterials such as semiconductor nanowires have unique features that could enable novel optoelectronic applications such as novel solar cells. This paper aims to demonstrate one such recently proposed concept: Monolithically Integrated Laterally Arrayed Multiple Band gap (MILAMB) solar cells for spectrum-splitting photovoltaic systems. Two cells with different band gaps were fabricated simultaneously in the same process on a single substrate using spatially composition-graded CdSSe alloy nanowires grown by the Dual-Gradient Method in a chemical vapor deposition system. CdSSe nanowire ensemble devices tested under 1 sun AM1.5G illumination achieved open-circuit voltages up to 307 and 173 mV and short-circuit current densities as high as 0.091 and 0.974 mA/cm(2) for the CdS- and CdSe-rich cells, respectively. The open-circuit voltages were roughly three times those of similar CdSSe film cells fabricated for comparison due to the superior optical quality of the nanowires. I-V measurements were also performed using optical filters to simulate spectrum-splitting. The open-circuit voltages and fill factors of the CdS-rich subcells were uniformly larger than the corresponding CdSe-rich cells for similar photon flux, as expected. This suggests that if all wires can be contacted, the wide-gap cell is expected to have greater output power than the narrow-gap cell, which is the key to achieving high efficiencies with spectrum-splitting. This paper thus provides the first proof-of-concept demonstration of simultaneous fabrication of MILAMB solar cells. This approach to solar cell fabrication using single-crystal nanowires for spectrum-splitting photovoltaics could provide a future low-cost high-efficiency alternative to the conventional high-cost high-efficiency tandem cells.

  17. Perovskite solar cells with CuSCN hole extraction layers yield stabilized efficiencies greater than 20%

    Science.gov (United States)

    Arora, Neha; Dar, M. Ibrahim; Hinderhofer, Alexander; Pellet, Norman; Schreiber, Frank; Zakeeruddin, Shaik Mohammed; Grätzel, Michael

    2017-11-01

    Perovskite solar cells (PSCs) with efficiencies greater than 20% have been realized only with expensive organic hole-transporting materials. We demonstrate PSCs that achieve stabilized efficiencies exceeding 20% with copper(I) thiocyanate (CuSCN) as the hole extraction layer. A fast solvent removal method enabled the creation of compact, highly conformal CuSCN layers that facilitate rapid carrier extraction and collection. The PSCs showed high thermal stability under long-term heating, although their operational stability was poor. This instability originated from potential-induced degradation of the CuSCN/Au contact. The addition of a conductive reduced graphene oxide spacer layer between CuSCN and gold allowed PSCs to retain >95% of their initial efficiency after aging at a maximum power point for 1000 hours under full solar intensity at 60°C. Under both continuous full-sun illumination and thermal stress, CuSCN-based devices surpassed the stability of spiro-OMeTAD-based PSCs.

  18. Wide band gap solar cells with high stabilized performance. Annual technical report, 15 July 1995--15 July 1996

    Energy Technology Data Exchange (ETDEWEB)

    Wronski, C R; Collins, R W; Fujiwara, H [Pennsylvania State Univ., University Park, PA (United States); and others

    1997-01-01

    This report describes work on an improved understanding of stability in materials and silicon solar cells. Topics include novel intrinsic materials optimization; solar cells optimized for p- and i-layer performance; novel p-type materials; interfaces; and device modeling.

  19. Full-spectrum light management by pseudo-disordered moth-eye structures for thin film solar cells.

    Science.gov (United States)

    Liu, Xiaojun; Da, Yun; Xuan, Yimin

    2017-08-07

    In this paper, the role of pseudo-disordered moth-eye structures on the optical features for application to thin-film solar cells is investigated to realize the superior light management for the full-spectrum solar energy utilization, compared with some ordered structures. Without loss of generality, the c-Si thin film solar cell is taken as the example. The results demonstrate that the fluctuations introduced into the geometry parameters of moth-eye elements can lead to the remarkable absorption enhancement in the wavelength region of 0.3-1.1 μm and high transmission in the wavelength range of 1.1-2.5 μm. Two mechanisms including the increasing spectral density of modes and the intensive forescattering intensity are identified to be responsible for the absorption enhancement. In addition, the optical characteristics of the moth-eye surface with both disordered height and disordered diameter are insensitive to the incident angle.

  20. Commentary Relative to the Emission Spectrum of the Solar Atmosphere: Further Evidence for a Distinct Solar Surface

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2013-07-01

    Full Text Available The chromosphere and corona of the Sun represent tenuous regions which are characterized by numerous optically thin emission lines in the ultraviolet and X-ray bands. When observed from the center of the solar disk outward, these emission lines experience modest brightening as the limb is approached. The intensity of many ultraviolet and X-ray emission lines nearly doubles when observation is extended just beyond the edge of the disk. These findings indicate that the solar body is opaque in this frequency range and that an approximately two fold greater region of the solar atmosphere is being sampled outside the limb. These observations provide strong support for the presence of a distinct solar surface. Therefore, the behavior of the emission lines in this frequency range constitutes the twenty fifth line of evidence that the Sun is comprised of condensed matter

  1. The Colloidal Stabilization of Quantum Dots: Towards Manufacturable, Efficient Solution-Processed Solar Cells

    Science.gov (United States)

    Rollny, Lisa

    Understanding colloidal stabilization can influence the design of optoelectronic devices and enable improvements to their performance and stability. For photovoltaics, important characteristics of the active layer material are high conductivity along with a minimum of recombination centers. In order to capitalize on the benefits of solution-processed materials, it is important to minimize the number of processing steps: ideally, to achieve a low-cost solution, materials would be deposited using a single process step compatible with roll-to-roll manufacturing. Prior to this work, the highest-performing colloidal quantum dots (CQD) solar cells have relied on several deposition steps that are repeated in a layer-by-layer (LBL) fashion. The purpose of these process steps has been to remove the long insulating ligands used in synthesis and replace them with short ligands that allow electrical conduction. The large number of steps combined, typically implemented via spin coating, leads to inefficient materials utilization and fails to show a path to a manufacturable solution. In this work, the first CQD solar cells were designed, built, and characterized combining state-of-art performance with scalable manufacture. Firstly, I report the first automated CQD synthesis to result in CQDs that form high-performance CQD solar cells. I analyze the CQD synthesis and by separating it into two phases---nucleation and growth phase---my insights are used to create higher-quality CQDs exhibiting enhanced monodispersity. I then proceed to develop a CQD ink: a CQD solution ready for direct deposition to form a semiconducting film exhibiting low trap state density. In early trials the CQD ink showed only limited power conversion efficiencies of 2%. I designed a new ink strategy, which I term cleavable hemiketal ligands. This novel two-component ligand strategy enables the combination of colloidal stabilization (via this longer two-component ligand) and cleavability (enabling excellent

  2. Performance and stability of P3HT/PCBM bulk heterojunction organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Yumnam, Nivedita; Bom, Sidhant; Wagner, Veit [School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, 28759 Bremen (Germany)

    2011-07-01

    Organic photovoltaic cells are promising candidates for large-area, low-cost production of solar cells. However, the low stability in conjunction with their medium performance is one of the major drawbacks in comparison to their inorganic counterparts. In this investigation environmental conditions for degradation of bulk heterojunction P3HT/PCBM solar cells are systematically analyzed over a period of one week. Devices were prepared by spin coating from different compositions of P3HT and PCBM in Chlorobenzene (C{sub 6}H{sub 5}Cl). Performance parameters, efficiency and I-V characteristics were determined in a N{sub 2} glove box showing optimized efficiency for a 1:1 ratio. Degradation behavior in N{sub 2} atmosphere, vacuum and solvent-enriched atmosphere (Chlorobenzene) showed best results for vacuum stored solar cells while for solvent-enriched atmosphere rapid degradation was observed. Remarkable degradation (open-circuit voltage and short-circuit current reduced to 90% and 60% after one week) was also found for N{sub 2} atmosphere of the glove box used for the solar cell production. Residual solvent vapor left dispersed in the atmosphere of the glovebox after the spin coating process is identified as an important parameter of this degradation.

  3. Stability of zinc phthalocyanine and fullerene C{sub 60} organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Lessmann, Rudolf

    2010-05-10

    Organic solar cells promise electricity generation at very low cost, and higher installation flexibility as compared to inorganic solar cells. The lower cost is achieved by cheaper semiconductors and easier manufacturing processes. The flexibility is naturally given by these ultra-thin, amorphous layers. Also the power conversion efficiency can be high enough for many applications. The organic molecules have to withstand the constant excitation by photons, transport of energy in form of excitons and charge. A small but significant amount of these photons has energy over the absorption gap, the excess of energy must be released without breaking the molecular bonds. In consequence, the solar cells can also heat up to temperatures at above 80 C. The objective of this work is to answer the question if the small molecules organic solar cells can be stable enough to operate under a very long time. The stability of organic doped layers in an organic solar cell is also addressed. This work starts with a general introduction followed by the description of the experimental procedures. The aging experiments of the solar cell were done with a self developed equipment. The fabrication of this equipment (a set of measurement boxes) was necessary to maintain the conditions, under which a solar cell can be aged, as constant as possible. The measurement boxes were used to control the electrical load of the cell, its temperature, the illumination intensity, and its electric connection to the I vs. V measurement equipment. A software package was also developed to control the equipment and to facilitate the work and visualization of the high volume of collected data. The model solar cells chosen for the aging experiments were donor-acceptor heterojunctions devices formed with the well-known materials C{sub 60} and ZnPc. Two basic different structures were analyzed, because they offered reasonable performance and potentially long lifetime: the flat heterojunction (FHJ) and the mixed

  4. A THEORETICAL AND NUMERICAL STUDY OF THERMOSOLUTAL CONVECTION: STABILITY OF A SALINITY GRADIENT SOLAR POND

    Directory of Open Access Journals (Sweden)

    Djamel Kalache

    2011-01-01

    Full Text Available A theoretical and numerical study of the effect of thermodiffusion on the stability of a gradient layer is presented. It intends to clarify the mechanisms of fluid dynamics and the processes which occur in a salinity gradient solar pond. A mathematical modelling is developed to describe the thermodiffusion contribution on the solar pond where thermal, radiative, and massive fluxes are coupled in the double diffusion. More realistic boundary conditions for temperature and concentration profiles are used. Our results are compared with those obtained experimentally by authors without extracting the heat flux from the storage zone. We have considered the stability analysis of the equilibrium solution. We assumed that the perturbation of quantities such as velocity, temperature, and concentration are infinitesimal. Linearized equations satisfying appropriate prescribed boundary conditions are then obtained and expanded into polynomials form. The Galerkin method along with a symbolic algebra code (Maple are used to solve these equations. The effect of the separation coefficient y is analyzed in the positive and negative case. We have also numerically compared the critical Rayleigh numbers for the onset of convection with those obtained by the linear stability analysis for Le = 100, µa = 0.8, and f = 0.5.

  5. Designing of new structure PID controller of boost converter for solar photovoltaic stability

    Science.gov (United States)

    Shabrina, Hanifati Nur; Setiawan, Eko Adhi; Sabirin, Chip Rinaldi

    2017-03-01

    Nowadays, the utilization of renewable energy as the source on distributed generation system is increasing. It aims to reduce reliance and power losses from utility grid and improve power stability in near loads. One example of renewable energy technology that have been highly proven on the market is solar photovoltaic (PV). This technology converts photon from sunlight into electricity. However, the fluctuation of solar radiation that often occurs become the main problem for this system. Due to this condition, the power conversion is needed to convert the change frequently in photovoltaic panel into a stable voltage to the system. Developing control of boost converter has important role to keep ability of system stabilization. A conventional PID (Proportional, Integral, Derivative) control is mostly used to achieve this goal. In this research, a design of new structure PID controller of boost converter is offered to better optimize system stability comparing to the conventional PID. Parameters obtained from this PID structure have been successfully yield a stable boost converter output at 200 V with 10% overshoot, 1.5 seconds of settling time, and 1.5% of steady-state error.

  6. Efficient full-spectrum utilization, reception and conversion of solar energy by broad-band nanospiral antenna.

    Science.gov (United States)

    Zhao, Huaqiao; Gao, Huotao; Cao, Ting; Li, Boya

    2018-01-22

    In this work, the collection of solar energy by a broad-band nanospiral antenna is investigated in order to solve the low efficiency of the solar rectenna based on conventional nanoantennas. The antenna impedance, radiation, polarization and effective area are all considered in the efficiency calculation using the finite integral technique. The wavelength range investigated is 300-3000 nm, which corresponds to more than 98% of the solar radiation energy. It's found that the nanospiral has stronger field enhancement in the gap than a nanodipole counterpart. And a maximum harvesting efficiency about 80% is possible in principle for the nanospiral coupled to a rectifier resistance of 200 Ω, while about 10% for the nanodipole under the same conditions. Moreover, the nanospiral could be coupled to a rectifier diode of high resistance more easily than the nanodipole. These results indicate that the efficient full-spectrum utilization, reception and conversion of solar energy can be achieved by the nanospiral antenna, which is expected to promote the solar rectenna to be a promising technology in the clean, renewable energy application.

  7. ADAPTIVE FULL-SPECTRUM SOLAR ENERGY SYSTEMS CROSS-CUTTING R&D ON ADAPTIVE FULL-SPECTRUM SOLAR ENERGY SYSTEMS FOR MORE EFFICIENT AND AFFORDABLE USE OF SOLAR ENERGY IN BUILDINGS AND HYBRID PHOTOBIOREACTORS

    Energy Technology Data Exchange (ETDEWEB)

    Byard D. Wood; Jeff D. Muhs

    2005-02-01

    This RD&D project is a three year team effort to develop a hybrid solar lighting (HSL) system that transports daylight from a paraboloidal dish concentrator to a luminaire via a bundle of small core or a large core polymer fiber optics. The luminaire can be a device to distribute sunlight into a space for the production of algae or it can be a device that is a combination of daylighting and electric lighting for space/task lighting. In this project, the sunlight is collected using a one-meter paraboloidal concentrator dish with two-axis tracking. For the second generation (alpha) system, the secondary mirror is an ellipsoidal mirror that directs the visible light into a bundle of small-core fibers. The IR spectrum is filtered out to minimize unnecessary heating at the fiber entrance region. This report describes the following investigations of various aspects of the system: (1) Performance specifications were developed for the tracking subsystem and collector optics, (2) Thermal management experiments for the fiber optic bundle entrance region, and (3) Bioreactor testing, cost-modeling, and redesign. Much of the planned work has been slowed due to significant procurement delays of the primary mirror. However, taken as a whole, they do confirm progress towards the technical feasibility and commercial viability of this technology. Due to this procurement delay, a no-cost extension of the project completion date has been requested and approved.

  8. An empirical line-by-line model for the infrared solar transmittance spectrum from 700 to 5000cm{sup -1}

    Energy Technology Data Exchange (ETDEWEB)

    Hase, F. [Institut fuer Meteorologie und Klimaforschung, Forschungszentrum Karlsruhe, Postfach 3640, D-76021 Karlsruhe (Germany)]. E-mail: frank.hase@imk.fzk.de; Demoulin, P. [Institut d' Astrophysique et de Geophysique, allee du VI aout, 17, batiment B5a, B-4000, Liege (Belgium); Sauval, A.J. [Observatoire Royal de Belgique, avenue circulaire, 3, B-1180, Bruxelles (Belgium); Toon, G.C. [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Bernath, P.F. [Department of Chemistry, University of Waterloo, Waterloo, Ont., Canada N2L3G1 (Canada); Goldman, A. [Department of Physics, University of Denver, Denver, CO 80208 (United States); Hannigan, J.W. [Atmospheric Chemistry Division, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80303 (United States); Rinsland, C.P. [NASA Langley Research Center, Hampton, VA 23681-2199 (United States)

    2006-12-15

    An empirical line-by-line model for the infrared solar transmittance spectrum is presented. The model can be incorporated into radiative transfer codes to allow fast calculation of all relevant emission and absorption features in the solar spectrum in the mid-infrared region from 700 to 5000cm{sup -1}. The transmittance is modelled as a function of the diameter of the field-of-view centered on the solar disk: the line broadening due to solar rotation as well as center-to-limb variations in strength and width are taken into account for stronger lines. Applications of the model presented here are in the fields of terrestrial remote sensing in the mid-infrared spectral region when the sun is used as radiation source or scattered solar radiation contributes to the measured signal and in the fields of atmospheric radiative transfer algorithms which compute the propagation of infrared solar radiation in the terrestrial atmosphere.

  9. An inter-laboratory stability study of roll-to-roll coated flexible polymer solar modules

    DEFF Research Database (Denmark)

    Gevorgyan, Suren; Medford, Andrew James; Bundgaard, Eva

    2011-01-01

    A large number of flexible polymer solar modules comprising 16 serially connected individual cells was prepared at the experimental workshop at Risø DTU. The photoactive layer was prepared from several varieties of P3HT (Merck, Plextronics, BASF and Risø DTU) and two varieties of ZnO (nanoparticu......A large number of flexible polymer solar modules comprising 16 serially connected individual cells was prepared at the experimental workshop at Risø DTU. The photoactive layer was prepared from several varieties of P3HT (Merck, Plextronics, BASF and Risø DTU) and two varieties of Zn......O (nanoparticulate, thin film) were employed as electron transport layers. The devices were all tested at Risø DTU and the functional devices were subjected to an inter-laboratory study involving the performance and the stability of modules over time in the dark, under light soaking and outdoor conditions. 24...

  10. Film Grain-Size Related Long-Term Stability of Inverted Perovskite Solar Cells.

    Science.gov (United States)

    Chiang, Chien-Hung; Wu, Chun-Guey

    2016-09-22

    The power conversion efficiency (PCE) of the perovskite solar cell is high enough to be commercially viable. The next important issue is the stability of the device. This article discusses the effect of the perovskite grain-size on the long-term stability of inverted perovskite solar cells. Perovskite films composed of various sizes of grains were prepared by controlling the solvent annealing time. The grain-size related stability of the inverted cells was investigated both in ambient atmosphere at relative humidity of approximately 30-40 % and in a nitrogen filled glove box (H 2 Operovskite film having the grain size larger than 1 μm (D-10) decreases less than 10 % with storage in a glove box and less than 15 % when it was stored under an ambient atmosphere for 30 days. However, the cell using the perovskite film composed of small (∼100 nm) perovskite grains (D-0) exhibits complete loss of PCE after storage under the ambient atmosphere for only 15 days and a PCE loss of up to 70 % with storage in the glove box for 30 days. These results suggest that, even under H 2 O-free conditions, the chemical- and thermal-induced production of pin holes at the grain boundaries of the perovskite film could be the reason for long-term instability of inverted perovskite solar cells. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Photocharge accumulation and recombination in perovskite solar cells regarding device performance and stability

    Science.gov (United States)

    Li, Yusheng; Li, Yiming; Shi, Jiangjian; Li, Hongshi; Zhang, Huiyin; Wu, Jionghua; Li, Dongmei; Luo, Yanhong; Wu, Huijue; Meng, Qingbo

    2018-01-01

    Photocharge accumulation and recombination in perovskite solar cells have been systematically investigated in this paper by electrochemical spectroscopy and transient photocurrent/photovoltage methods. It is found that the non-equilibrium photocharges stored in the selective charge transport layers follow a backward recombination mechanism. That is, the photocharges are first captured by the interface defects corresponding to the fast photovoltage decay, while the bulk charge recombination instead of the diffusion process dominates the slow photovoltage decay process. Further investigation reveals that the device degradation preferentially takes place at the interface under working conditions, which thus can confirm the importance of interface engineering to enhance the device stability.

  12. Film thickness and chemical processing effects on the stability of cadmium telluride solar cells

    International Nuclear Information System (INIS)

    Albin, D.S.; Demtsu, S.H.; McMahon, T.J.

    2006-01-01

    The performance and stability of CdS/CdTe solar cells as a function of layer thickness, back contact etch, and oxygen during the CdCl 2 anneal was determined. Multiple linear regression models were used to analyze the statistical significance of various first order effects and interactions. With stress, all devices showed a reduction in open-circuit voltage (V oc ) and fill factor (FF) characteristic of increased recombination. Devices using thinner CdS were vulnerable to shunt formation. Oxygen during the CdCl 2 anneal minimizes this effect. A thermodynamic model involving the formation of Cu-oxide is presented to explain the latter

  13. Analytical Prediction of the Spin Stabilized Satellite's Attitude Using The Solar Radiation Torque

    International Nuclear Information System (INIS)

    Motta, G B; Carvalho, M V; Zanardi, M C

    2013-01-01

    The aim of this paper is to present an analytical solution for the spin motion equations of spin-stabilized satellite considering only the influence of solar radiation torque. The theory uses a cylindrical satellite on a circular orbit and considers that the satellite is always illuminated. The average components of this torque were determined over an orbital period. These components are substituted in the spin motion equations in order to get an analytical solution for the right ascension and declination of the satellite spin axis. The time evolution for the pointing deviation of the spin axis was also analyzed. These solutions were numerically implemented and compared with real data of the Brazilian Satellite of Data Collection – SCD1 an SCD2. The results show that the theory has consistency and can be applied to predict the spin motion of spin-stabilized artificial satellites

  14. Full solar spectrum light driven thermocatalysis with extremely high efficiency on nanostructured Ce ion substituted OMS-2 catalyst for VOCs purification

    Science.gov (United States)

    Hou, Jingtao; Li, Yuanzhi; Mao, Mingyang; Yue, Yuanzheng; Greaves, G. Neville; Zhao, Xiujian

    2015-01-01

    The nanostructured Ce ion substituted cryptomelane-type octahedral molecular sieve (OMS-2) catalyst exhibits strong absorption in the entire solar spectrum region. The Ce ion substituted OMS-2 catalyst can efficiently transform the absorbed solar energy to thermal energy, resulting in a considerable increase of temperature. By combining the efficient photothermal conversion and thermocatalytic activity of the Ce ion substituted OMS-2 catalyst, we carried out full solar spectrum, visible-infrared, and infrared light driven catalysis with extremely high efficiency. Under the irradiation of full solar spectrum, visible-infrared, and infrared light, the Ce ion substituted OMS-2 catalyst exhibits extremely high catalytic activity and excellent durability for the oxidation of volatile organic pollutants such as benzene, toluene, and acetone. Based on the experimental evidence, we propose a novel mechanism of solar light driven thermocatalysis for the Ce ion substituted OMS-2 catalyst. The reason why the Ce ion substituted OMS-2 catalyst exhibits much higher catalytic activity than pure OMS-2 and CeO2/OMS-2 nano composite under the full solar spectrum irradiation is discussed.The nanostructured Ce ion substituted cryptomelane-type octahedral molecular sieve (OMS-2) catalyst exhibits strong absorption in the entire solar spectrum region. The Ce ion substituted OMS-2 catalyst can efficiently transform the absorbed solar energy to thermal energy, resulting in a considerable increase of temperature. By combining the efficient photothermal conversion and thermocatalytic activity of the Ce ion substituted OMS-2 catalyst, we carried out full solar spectrum, visible-infrared, and infrared light driven catalysis with extremely high efficiency. Under the irradiation of full solar spectrum, visible-infrared, and infrared light, the Ce ion substituted OMS-2 catalyst exhibits extremely high catalytic activity and excellent durability for the oxidation of volatile organic pollutants

  15. Solar-Iss a New Solar Reference Spectrum Covering the Far UV to the Infrared (165 to 3088 Nm) Based on Reanalyzed Solar/solspec Cycle 24 Observations

    Science.gov (United States)

    Damé, L.; Meftah, M.; Irbah, A.; Hauchecorne, A.; Bekki, S.; Bolsée, D.; Pereira, N.; Sluse, D.; Cessateur, G.

    2017-12-01

    Since April 5, 2008 and until February 15, 2017, the SOLSPEC (SOLar SPECtrometer) spectro-radiometer of the SOLAR facility on the International Space Station performed accurate measurements of Solar Spectral Irradiance (SSI) from the far ultraviolet to the infrared (165 nm to 3088 nm). These measurements, unique by their large spectral coverage and long time range, are of primary importance for a better understanding of solar physics and of the impact of solar variability on climate (via Earth's atmospheric photochemistry), noticeably through the "top-down" mechanism amplifying ultraviolet (UV) solar forcing effects on the climate (UV affects stratospheric dynamics and temperatures, altering interplanetary waves and weather patterns both poleward and downward to the lower stratosphere and troposphere regions). SOLAR/SOLSPEC, with almost 9 years of observations covering the essential of the unusual solar cycle 24 from minimum in 2008 to maximum, allowed to establish new reference solar spectra from UV to IR (165 to 3088 nm) at minimum (beginning of mission) and maximum of activity. The complete reanalysis was possible thanks to revised engineering corrections, improved calibrations and advanced procedures to account for thermal, aging and pointing corrections. The high quality and sensitivity of SOLSPEC data allow to follow temporal variability in UV but also in visible along the cycle. Uncertainties on these measurements are evaluated and results, absolute reference spectra and variability, are compared with other measurements (WHI, ATLAS-3, SCIAMACHY, SORCE/SOLSTICE, SORCE/SIM) and models (SATIRE-S, NRLSSI, NESSY)

  16. Full Solar Spectrum Light Driven Thermocatalysis with Extremely High Efficiency on Nanostructured Ce Ion Substituted OMS-2 Catalyst for VOCs Purification

    DEFF Research Database (Denmark)

    Hou, J.T.; Li, Y.Z.; Mao, M.Y.

    2015-01-01

    solar spectrum, visible-infrared, and infrared light, the Ce ion substituted OMS-2 catalyst exhibits extremely high catalytic activity and excellent durability for the oxidation of volatile organic pollutants such as benzene, toluene, and acetone. Based on the experimental evidence, we propose a novel...... in a considerable increase of temperature. By combining the efficient photothermal conversion and thermocatalytic activity of the Ce ion substituted OMS-2 catalyst, we carried out full solar spectrum, visible-infrared, and infrared light driven catalysis with extremely high efficiency. Under the irradiation of full...... mechanism of solar light driven thermocatalysis for the Ce ion substituted OMS-2 catalyst. The reason why the Ce ion substituted OMS-2 catalyst exhibits much higher catalytic activity than pure OMS-2 and CeO2/OMS-2 nano composite under the full solar spectrum irradiation is discussed....

  17. Stability of dye-sensitized solar cells under extended thermal stress.

    Science.gov (United States)

    Yadav, Surendra K; Ravishankar, Sandheep; Pescetelli, Sara; Agresti, Antonio; Fabregat-Santiago, Francisco; Di Carlo, Aldo

    2017-08-23

    In the last few decades, dye-sensitized solar cell (DSC) technology has been demonstrated to be a promising candidate for low cost energy production due to cost-effective materials and fabrication processes. Arguably, DSC stability is the biggest challenge for making this technology appealing for industrial exploitation. This work provides further insight into the stability of DSCs by considering specific dye-electrolyte systems characterized by Raman and impedance spectroscopy analysis. In particular, two ruthenium-based dyes, Z907 and Ru505, and two commercially available electrolytes, namely, the high stability electrolyte (HSE) and solvent-free Livion 12 (L-12), were tested. After 4700 h of thermal stress at 85 °C, the least stable device composed of Z907/HSE showed an efficiency degradation rate of ∼14%/1000 h, while the Ru505/L-12 system retained 96% of its initial efficiency by losing ∼1% each 1000 h. The present results show a viable route to stabilize the DSC technology under prolonged annealing conditions complying with the IEC standard requirements.

  18. An analysis of vibration-rotation lines of OH in the solar infrared spectrum

    NARCIS (Netherlands)

    Grevesse, N.; Sauval, A.J.; Dishoeck, van E.F.

    1984-01-01

    High resolution solar spectra have permitted the measurement with great accuracy of equivalent widths of vibration-rotation lines of OH in the X2Pi state near 3-micron wavelength. Using recent theoretical results for the transition probabilities, a solar oxygen abundance of (8.93 + or - 0.02) is

  19. Automated solar radio burst detection on radio spectrum: a review of ...

    African Journals Online (AJOL)

    By doing manual detection, human effort and error become the issues when the solar astronomer needs the fast and accurate result. Recently, the success of various techniques in image processing to identify solar radio burst automatically was presented. This paper reviews previous technique in image processing.

  20. 100 °C Thermal Stability of Printable Perovskite Solar Cells Using Porous Carbon Counter Electrodes.

    Science.gov (United States)

    Baranwal, Ajay K; Kanaya, Shusaku; Peiris, T A Nirmal; Mizuta, Gai; Nishina, Tomoya; Kanda, Hiroyuki; Miyasaka, Tsutomu; Segawa, Hiroshi; Ito, Seigo

    2016-09-22

    Many efforts have been made towards improving perovskite (PVK) solar cell stability, but their thermal stability, particularly at 85 °C (IEC 61646 climate chamber tests), remains a challenge. Outdoors, the installed solar cell temperature can reach up to 85 °C, especially in desert regions, providing sufficient motivation to study the effect of temperature stress at or above this temperature (e.g., 100 °C) to confirm the commercial viability of PVK solar cells for industrial companies. In this work, a three-layer printable HTM-free CH 3 NH 3 PbI 3 PVK solar cell with a mesoporous carbon back contact and UV-curable sealant was fabricated and tested for thermal stability over 1500 h at 100 °C. Interestingly, the position of the UV-curing glue was found to drastically affect the device stability. The side-sealed cells show high PCE stability and represent a large step toward commercialization of next generation organic-inorganic lead halide PVK solar cells. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Variation of the Solar Microwave Spectrum in the Last Half Century

    Energy Technology Data Exchange (ETDEWEB)

    Shimojo, Masumi; Saito, Masao [National Astronomical Observatory of Japan (NAOJ), National Institutes of Natural Sciences (NINS), Mitaka, Tokyo, 181-8588 (Japan); Iwai, Kazumasa [Institute for Space-Earth Environmental Research (ISEE), Nagoya University, Chikusa-ku, Nagoya, 464-8601 (Japan); Asai, Ayumi [Kwasan and Hida Observatories, Kyoto University, Sakyo-ku, Kyoto, 606-8502 (Japan); Nozawa, Satoshi [Department of Science, Ibaraki University, Mito, Ibaraki, 310-8512 (Japan); Minamidani, Tetsuhiro, E-mail: masumi.shimojo@nao.ac.jp [Department of Astronomical Science, School of Physical Science, SOKENDAI (The Graduate University of Advanced Studies), Mitaka, Tokyo, 181-8588 (Japan)

    2017-10-10

    The total solar fluxes at 1, 2, 3.75, and 9.4 GHz were observed continuously from 1957 to 1994 at Toyokawa, Japan, and from 1994 until now at Nobeyama, Japan, with the current Nobeyama Radio Polarimeters. We examined the multi-frequency and long-term data sets, and found that not only the microwave solar flux but also its monthly standard deviation indicate the long-term variation of solar activity. Furthermore, we found that the microwave spectra at the solar minima of Cycles 20–24 agree with each other. These results show that the average atmospheric structure above the upper chromosphere in the quiet-Sun has not varied for half a century, and suggest that the energy input for atmospheric heating from the sub-photosphere to the corona have not changed in the quiet-Sun despite significantly differing strengths of magnetic activity in the last five solar cycles.

  2. A new photocrosslinkable oligothiophene for organic solar cells with enhanced stability

    Energy Technology Data Exchange (ETDEWEB)

    Lanzi, Massimiliano, E-mail: massimiliano.lanzi@unibo.it [Department of Industrial Chemistry “Toso Montanari”, University of Bologna, Viale Risorgimento 4, 40136 Bologna (Italy); Salatelli, Elisabetta; Di-Nicola, Francesco Paolo; Zuppiroli, Luca [Department of Industrial Chemistry “Toso Montanari”, University of Bologna, Viale Risorgimento 4, 40136 Bologna (Italy); Pierini, Filippo [Department of Mechanics and Physics of Fluids, Institute of Fundamental Technological Research, Polish Academy of Sciences, ul. Pawinskiego 5B, 02-106 Warsaw (Poland)

    2017-01-15

    A novel thiophenic tetramer containing a cinnamate group in the side chain with a functionalization degree of 50% is reported. The tetramer was obtained by means of a simple and straightforward procedure involving the functionalization of a p-methoxyphenoxy substituted thiophenic precursor, which led to a soluble product with a good yield. The oligomer was fully characterized from a structural and chemical point of view and employed for the fabrication of small molecule organic solar cells exploiting the bulk heterojunction (BHJ) architecture. The presence of an UV-light sensitive group in the tetramer allowed the photocrosslinking of tetramer/PCBM blends, giving high values of photocurrent and conversion efficiency for the exposed samples. Moreover, the UV-treated devices showed improved stability, even upon heating for three days at 130 °C, thus confirming that photocrosslinking can strongly reduce phase segregation under severe operational conditions. - Graphical abstract: 3D-visualization of a T4CIN/PCBM layer portion. - Highlights: • A photocrosslinkable thiophenic electron-donor oligomer has been synthesized. • It has been characterized and used to prepare BHJ SMO Solar Cells. • Cells electrical performances and thermal stabilities have been evaluated. • A comparison between UV-cured and pristine cells has been made.

  3. Measurement of the Cosmic-Ray Antiproton Spectrum at Solar Minimum with a Long-Duration Balloon Flight over Antarctica

    Science.gov (United States)

    Abe, K.; Fuke, H.; Haino, S.; Hams, T.; Hasegawa, M.; Horikoshi, A.; Kim, K. C.; Kusumoto, A.; Lee, M. H.; Makida, Y.; hide

    2012-01-01

    The energy spectrum of cosmic-ray antiprotons (p-bar's) from 0.17 to 3.5 GeV has been measured using 7886 p-bar's detected by BESS-Polar II during a long-duration flight over Antarctica near solar minimum in December 2007 and January 2008. This shows good consistency with secondary p-bar calculations. Cosmologically primary p-bar's have been investigated by comparing measured and calculated p-bar spectra. BESS-Polar II data.show no evidence of primary p-bar's from the evaporation of primordial black holes.

  4. Stability and Change in Autism Spectrum Disorder Diagnosis from Age 3 to Middle Childhood in a High-Risk Sibling Cohort

    Science.gov (United States)

    Brian, Jessica; Bryson, Susan E.; Smith, Isabel M.; Roberts, Wendy; Roncadin, Caroline; Szatmari, Peter; Zwaigenbaum, Lonnie

    2016-01-01

    Considerable evidence on autism spectrum disorder emergence comes from longitudinal high-risk samples (i.e. younger siblings of children with autism spectrum disorder). Diagnostic stability to age 3 is very good when diagnosed as early as 18-24 months, but sensitivity is weaker, and relatively little is known beyond toddlerhood. We examined…

  5. Stability under scalar perturbations and quasinormal modes of 4D Einstein-Born-Infeld dilaton spacetime. Exact spectrum

    International Nuclear Information System (INIS)

    Destounis, Kyriakos; Panotopoulos, Grigoris; Rincon, Angel

    2018-01-01

    We study the stability under scalar perturbations, and we compute the quasinormal modes of the Einstein-Born-Infeld dilaton spacetime in 1 + 3 dimensions. Solving the full radial equation in terms of hypergeometric functions, we provide an exact analytical expression for the spectrum. We find that the frequencies are purely imaginary, and we confirm our results by computing them numerically. Although the scalar field that perturbs the black hole is electrically neutral, an instability similar to that seen in charged scalar perturbations of the Reissner-Nordstroem black hole is observed. (orig.)

  6. Stability under scalar perturbations and quasinormal modes of 4D Einstein-Born-Infeld dilaton spacetime. Exact spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Destounis, Kyriakos; Panotopoulos, Grigoris [Universidade de Lisboa, Centro Multidisciplinar de Astrofisica, Instituto Superior Tecnico, Lisbon (Portugal); Rincon, Angel [Pontificia Universidad Catolica de Chile, Instituto de Fisica, Santiago (Chile)

    2018-02-15

    We study the stability under scalar perturbations, and we compute the quasinormal modes of the Einstein-Born-Infeld dilaton spacetime in 1 + 3 dimensions. Solving the full radial equation in terms of hypergeometric functions, we provide an exact analytical expression for the spectrum. We find that the frequencies are purely imaginary, and we confirm our results by computing them numerically. Although the scalar field that perturbs the black hole is electrically neutral, an instability similar to that seen in charged scalar perturbations of the Reissner-Nordstroem black hole is observed. (orig.)

  7. Stability and change of IQ scores in preschool children diagnosed with autistic spectrum disorder.

    NARCIS (Netherlands)

    Dietz, C.; Swinkels, S.H.N.; Buitelaar, J.K.; Daalen, E. van; Engeland, H.M. van

    2007-01-01

    AIM: To investigate cognitive development in preschool-age children diagnosed with Autistic Spectrum Disorder (ASD; N = 39) compared with that of children diagnosed with mental retardation (MR; N = 14) and normally developing children (NC; N = 36). METHOD: In a prospective longitudinal study,

  8. Empathizing and Systemizing in Adults with and without Autism Spectrum Conditions: Cross-Cultural Stability

    Science.gov (United States)

    Wakabayashi, Akio; Baron-Cohen, Simon; Uchiyama, Tokio; Yoshida, Yuko; Kuroda, Miho; Wheelwright, Sally

    2007-01-01

    This study tests the empathizing-systemizing (E-S) theory of sex differences and the extreme male brain (EMB) theory of autism. Three groups of participants took part: n = 48 people with autism spectrum, n = 137 general population controls, and n = 1,250 university student controls. Each participant completed the Empathy Quotient (EQ) and the…

  9. Fast and Accurate Hybrid Stream PCRTMSOLAR Radiative Transfer Model for Reflected Solar Spectrum Simulation in the Cloudy Atmosphere

    Science.gov (United States)

    Yang, Qiguang; Liu, Xu; Wu, Wan; Kizer, Susan; Baize, Rosemary R.

    2016-01-01

    A hybrid stream PCRTM-SOLAR model has been proposed for fast and accurate radiative transfer simulation. It calculates the reflected solar (RS) radiances with a fast coarse way and then, with the help of a pre-saved matrix, transforms the results to obtain the desired high accurate RS spectrum. The methodology has been demonstrated with the hybrid stream discrete ordinate (HSDO) radiative transfer (RT) model. The HSDO method calculates the monochromatic radiances using a 4-stream discrete ordinate method, where only a small number of monochromatic radiances are simulated with both 4-stream and a larger N-stream (N = 16) discrete ordinate RT algorithm. The accuracy of the obtained channel radiance is comparable to the result from N-stream moderate resolution atmospheric transmission version 5 (MODTRAN5). The root-mean-square errors are usually less than 5x10(exp -4) mW/sq cm/sr/cm. The computational speed is three to four-orders of magnitude faster than the medium speed correlated-k option MODTRAN5. This method is very efficient to simulate thousands of RS spectra under multi-layer clouds/aerosols and solar radiation conditions for climate change study and numerical weather prediction applications.

  10. Solar-blind wurtzite MgZnO alloy films stabilized by Be doping

    International Nuclear Information System (INIS)

    Su, Longxing; Zhu, Yuan; Zhang, Quanlin; Chen, Mingming; Ji, Xu; Wu, Tianzhun; Gui, Xuchun; Xiang, Rong; Tang, Zikang; Pan, Bicai

    2013-01-01

    Mg x Zn 1−x O alloy films were deposited on c-plane sapphire substrates by radio frequency plasma-assisted molecular beam epitaxy (rf-PMBE). The phase segregation occurred when x was larger than 33%. Be doping was found experimentally able to stabilize the high-Mg-content MgZnO alloy. By alloying 1–2% Be into MgZnO, the band gap of as-prepared quaternary alloys can be raised to the solar-blind range (4.5 eV). Calculated formation energy of the alloys based on first principle reveals that a small amount of Be incorporation can reduce the formation energy of high-Mg-content MgZnO alloys and results in a more stable system, which justifies our experimental observations. (paper)

  11. Effects of Annealing Conditions on Mixed Lead Halide Perovskite Solar Cells and Their Thermal Stability Investigation.

    Science.gov (United States)

    Yang, Haifeng; Zhang, Jincheng; Zhang, Chunfu; Chang, Jingjing; Lin, Zhenhua; Chen, Dazheng; Xi, He; Hao, Yue

    2017-07-21

    In this work, efficient mixed organic cation and mixed halide (MA 0.7 FA 0.3 Pb(I 0.9 Br 0.1 )₃) perovskite solar cells are demonstrated by optimizing annealing conditions. AFM, XRD and PL measurements show that there is a better perovskite film quality for the annealing condition at 100 °C for 30 min. The corresponding device exhibits an optimized PCE of 16.76% with V OC of 1.02 V, J SC of 21.55 mA/cm² and FF of 76.27%. More importantly, the mixed lead halide perovskite MA 0.7 FA 0.3 Pb(I 0.9 Br 0.1 )₃ can significantly increase the thermal stability of perovskite film. After being heated at 80 °C for 24 h, the PCE of the MA 0.7 FA 0.3 Pb(I 0.9 Br 0.1 )₃ device still remains at 70.00% of its initial value, which is much better than the control MAPbI₃ device, where only 46.50% of its initial value could be preserved. We also successfully fabricated high-performance flexible mixed lead halide perovskite solar cells based on PEN substrates.

  12. Polarized Light from the Sun: Unification of the Corona and Analysis of the Second Solar Spectrum — Further Implications of a Liquid Metallic Hydrogen Solar Model

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2015-07-01

    in the chromosphere. The prevalence of polarized signals from the Rare Earth metals, a chemically unique group of the periodic table, provides powerful evidence, based on the “Second Solar Spectrum”, that chemical reactions and coordination are taking place in the atmosphere of the Sun. This concept is also supported by the polarized signal from lithium, an element previously hypothesized to assist in stabilizing metallic hydrogen structures. The possibility that some atoms are coordinated with CHS implies that the relative abundance of elements cannot be simply ascertained through the analysis of emission or absorption lines in the solar atmosphere.

  13. Modelling the autocovariance of the power spectrum of a solar-type oscillator

    DEFF Research Database (Denmark)

    Campante , T.L.; Karoff, Christoffer

    2010-01-01

    tool in the analysis of the more than 1000 solar-type stars expected to be observed as part of the Kepler Asteroseismic Investigation (KAI). We apply the aforementioned procedure to simulations of the Sun. Assuming different apparent magnitudes, we address the issues of how accurately and how precisely...

  14. Synergistic effect of broad-spectrum Sunscreens and antihistamines in the control of idiopathic solar urticaria

    DEFF Research Database (Denmark)

    Faurschou, A.; Wulf, Hans Chr.

    2008-01-01

    . Observations: Three patients with idiopathic solar urticaria underwent phototesting with UV-B and UV-A radiation. The minimal urticarial dose (MUD) was determined 15 minutes after irradiation. The patients were subsequently tested with 5 times the MUD, and the reaction was graded every minute for 15 minutes...

  15. Outdoor Operational Stability of Indium-Free Flexible Polymer Solar Modules Over 1 Year Studied in India, Holland, and Denmark

    DEFF Research Database (Denmark)

    Angmo, Dechan; Sommeling, Paul M.; Gupta, Ritu

    2014-01-01

    We present an outdoor interlaboratory stability study of fully printed and coated indium-tin-oxide (ITO)-free polymer solar cell modules in JNCASR Bangalore (India), ECN (Holland), and DTU (Denmark) carried over more than 1 year. The modules comprising a fully printed and coated stack (Ag grid...

  16. A roll-to-roll process to flexible polymer solar cells: model studies, manufacture and operational stability studies

    DEFF Research Database (Denmark)

    Krebs, Frederik C; Gevorgyan, Suren; Alstrup, Jan

    2009-01-01

    An inverted polymer solar cell geometry comprising a total of five layers was optimized using laboratory scale cells and the operational stability was studied under model atmospheres. The device geometry was substrate-ITO-ZnO-(active layer)-PEDOT:PSS-silver with P3HT-PCBM as the active layer. The...

  17. Interface engineering of perovskite solar cells with multifunctional polymer interlayer toward improved performance and stability

    Science.gov (United States)

    Huang, Li-Bo; Su, Pei-Yang; Liu, Jun-Min; Huang, Jian-Feng; Chen, Yi-Fan; Qin, Su; Guo, Jing; Xu, Yao-Wei; Su, Cheng-Yong

    2018-02-01

    This work proposes a new perovskite solar cell structure by inserting a polymer interlayer between perovskite and hole transporting material (HTM) to minimize the interface losses via interface engineering. The multifunctional interlayers improve the photovoltaic efficiency and device stability by shielding perovskite from moisture, suppressing charge combination, and promoting hole transport. The five different polymer layers are utilized to investigate the relationships of polymer structure, layer morphology and cell performance systematically. It is found that a reliable power conversion efficiency exceeding 19.0% is realized based on P3HT/spiro-OMeTAD composite structure, surpassing that of pure spiro-OMeTAD (15.0%). Moreover, the device with P3HT interlayer shows more brilliant long-term stability than that without interlayer when exposed into moisture. The enhanced device performance based on P3HT interlayer compared with the other polymers can be ascribed to the long hydrophobic alkyl chains and the small molecule monomers of P3HT, which contribute to self-assembly of the polymers into insulating layers and formation of the efficient π-π stacking in polymer/spiro-OMeTAD interface simultaneously. This study provides a practical route for the integration of a new class of easily-accessible, solution-processed interfacial polymer materials for high-performance and long-time stable PSC.

  18. An artificial solar spectrum substantially alters plant development compared with usual climate room irradiance spectra

    NARCIS (Netherlands)

    Hogewoning, S.W.; Douwstra, P.; Trouwborst, G.; Ieperen, van W.; Harbinson, J.

    2010-01-01

    Plant responses to the light spectrum under which plants are grown affect their developmental characteristics in a complicated manner. Lamps widely used to provide growth irradiance emit spectra which are very different from natural daylight spectra. Whereas specific responses of plants to a

  19. Stable amorphous semiconductors for solar cells. Final report; Stabile amorphe Halbleiterfilme fuer Solarzellen. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Fuhs, W.; Lips, K.; Mell, H.; Stachowitz, R.; Will, S.; Ulber, I.

    1997-12-31

    This study was founded on the preceding projects. The main objective was the preparation and characterization of stable amorphous silicon films (a-Si:H) by plasma enhanced chemical vapor deposition (PECVD). For this purpose the deposition conditions were varied in a wide range. The main effort was on the change of the reactor geometry and the increase of the substrate temperature to values beyond 250 C. Comparative studies of the film stability were carried out using different degradation techniques. The electronic and structural properties of the films were investigated with the aim to find correlations between the stability and other film properties. Information on the defect density was obtained from electron spin resonance (ESR), photothermal deflection spectroscopy (PDS) and photocurrent spectroscopy (CPM). The influence of native and light-induced defects on the recombination kinetics was studied using both films and solar cells. The techniques mainly used for that were steady-state and frequency-resolved photoluminescence spectroscopy (FRS) and electrically detected magnetic resonance (EDMR). The results of these studies were published in international journals and presented at international conferences. (orig.) [Deutsch] Das Vorhaben baute auf den vorangegangenen Projekten auf. Wichtigstes Ziel war die Herstellung und Charakterisierung stabiler amorpher Siliziumfilme (a-Si:H) durch Plasmadeposition. Dazu wurden die Depositionsbedingungen in einem weiten Bereich variiert. Im Vordergrund standen dabei die Aenderung der Reaktorgeometrie und die Erhoehung der Substrattemperatur auf Werte oberhalb von 250 C. Die Stabilitaet der Filme wurde mit verschiedenen Degradationsverfahren vergleichend geprueft. Die Filme wurden hinsichtlich ihrer elektronischen und strukturellen Eigenschaften mit dem Ziel untersucht, einen Zusammenhang zwischen der Stabilitaet und anderen Probeneigenschaften aufzufinden. Als Messverfahren fuer die Defektdichte standen

  20. Great SEP events and space weather: 2. Automatic determination of the solar energetic particle spectrum

    Science.gov (United States)

    Applbaum, David; Dorman, Lev; Pustil'Nik, Lev; Sternlieb, Abraham; Zagnetko, Alexander; Zukerman, Igor

    In Applbaum et al. (2010) it was described how the "SEP-Search" program works automat-ically, determining on the basis of on-line one-minute NM data the beginning of a great SEP event. The "SEP-Search" next uses one-minute data in order to check whether or not the observed increase reflects the beginning of a real great SEP event. If yes, the program "SEP-Research/Spectrum" automatically starts to work on line. We consider two variants: 1) quiet period (no change in cut-off rigidity), 2) disturbed period (characterized with possible changing of cut-off rigidity). We describe the method of determining the spectrum of SEP in the 1st vari-ant (for this we need data for at least two components with different coupling functions). For the 2nd variant we need data for at least three components with different coupling functions. We show that for these purposes one can use data of the total intensity and some different mul-tiplicities, but that it is better to use data from two or three NM with different cut-off rigidities. We describe in detail the algorithms of the program "SEP-Research/Spectrum." We show how this program worked on examples of some historical great SEP events. The work of NM on Mt. Hermon is supported by Israel (Tel Aviv University and ISA) -Italian (UNIRoma-Tre and IFSI-CNR) collaboration.

  1. Growth, etching, and stability of sputtered ZnO:Al for thin-film silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Owen, Jorj Ian

    2011-07-01

    Aluminum-doped zinc oxide (ZnO:Al) can fulfill many requirements in thin-film solar cells, acting as (1) a transparent contact through which the incident light is transmitted, (2) part of the back reflector, and (3) a source of light scattering. Magnetron sputtered ZnO:Al thin-films are highly transparent, conductive, and are typically texturized by post-deposition etching in a dilute hydrochloric acid (HCl) solution to achieve light scattering. The ZnO:Al thin-film electronic and optical properties, as well as the surface texture after etching, depend on the deposition conditions and the post-deposition treatments. Despite having been used in thin-film solar cells for more than a decade, many aspects regarding the growth, effects of heat treatments, environmental stability, and etching of sputtered ZnO:Al are not fully understood. This work endeavors to further the understanding of ZnO:Al for the purpose improving silicon thin-film solar cell efficiency and reducing ZnO:Al production costs. With regard to the growth of ZnO:Al, the influence of various deposition conditions on the resultant electrical and structural properties and their evolution with film thickness were studied. The surface electrical properties extracted from a multilayer model show that while carrier concentration of the surface layer saturates already at film thickness of 100 nm, the surface mobility continues to increases with film thickness, and it is concluded that electronic transport across grain boundaries limits mobility in ZnO:Al thin films. ZnO:Al deposited onto a previously etched ZnO:Al surface grows epitaxially, preserving both the original orientation and grain structure. Further, it is determined that a typical ZnO:Al used in thin-film silicon solar cells grows Zn-terminated on glass substrates. Concerning the affects of heat treatments and stability, it is demonstrated that a layer of amorphous silicon can protect ZnO:Al from degradation during annealing, and the mobility of Zn

  2. Radio wave scattering observations of the solar corona: First-order measurements of expansion velocity and turbulence spectrum using Viking and Mariner 10 spacecraft

    International Nuclear Information System (INIS)

    Tyler, G.L.; Vesecky, J.F.; Plume, M.A.; Howard, H.T.; Barnes, A.

    1981-01-01

    Solar conjunction of Mars on 1976 November 25 occurred very near the beginning of solar cycle 21, about 4 months after the first Viking spacecraft arrived at the planet. Radio wave scattering data were collected at 3.6 and 13 cm wavelengths, using the radio link between the Viking orbiters and the Earth. These data allow measurements of solar wind properties over a range of heliocentric radial distance from approx.6 to 44 R/sub sun/ with solar latitudes ranging from -17 0 to +7 0 . Observations with Mariner 10 during a period of moderate solar activity in 1974 cover from 6 to 24 R/sub sun/ and from approx.20 0 to near 90 0 . We have found that the temporal frequency variance spectrum of amplitude fluctuations is useful for characterizing the bulk motion of the plasma. This spectrum has an approximately constant low frequency plateau and a power-law high frequency asymptote; the plateau-asymptote intersection frequency provides a measure of the solar wind velocity V. We also obtain the spectral index p of electron density turbulence, Phi/sub N/approx.kappa/sup -p/, where kappa is spatial wavenumber. These results apply to a cylindrical region oriented with its axis along the radio ray path and its center at the point of closest approach to the Sun. The measurements of V and p cover some 78/sup d/ for Viking and 49 2 for Mariner 10 and show the combined effects of changing heliocentric distance rho, solar latitude theta, and solar longitude Psi, as well as solar activity. The Viking results can be regarded as a function primary of rho and Psi since the observations are concentrated in the equatorial regions when solar activity was near minimum. For Mariner 10, rho, theta, and Psi variations were important. The Viking results show an abrupt change in V(rho) and the turbulence spectral index at approx.15 R/sub sun/

  3. Off-axis holographic lens spectrum-splitting photovoltaic system for direct and diffuse solar energy conversion.

    Science.gov (United States)

    Vorndran, Shelby D; Chrysler, Benjamin; Wheelwright, Brian; Angel, Roger; Holman, Zachary; Kostuk, Raymond

    2016-09-20

    This paper describes a high-efficiency, spectrum-splitting photovoltaic module that uses an off-axis volume holographic lens to focus and disperse incident solar illumination to a rectangular shaped high-bandgap indium gallium phosphide cell surrounded by strips of silicon cells. The holographic lens design allows efficient collection of both direct and diffuse illumination to maximize energy yield. We modeled the volume diffraction characteristics using rigorous coupled-wave analysis, and simulated system performance using nonsequential ray tracing and PV cell data from the literature. Under AM 1.5 illumination conditions the simulated module obtained a 30.6% conversion efficiency. This efficiency is a 19.7% relative improvement compared to the more efficient cell in the system (silicon). The module was also simulated under a typical meteorological year of direct and diffuse irradiance in Tucson, Arizona, and Seattle, Washington. Compared to a flat panel silicon module, the holographic spectrum splitting module obtained a relative improvement in energy yield of 17.1% in Tucson and 14.0% in Seattle. An experimental proof-of-concept volume holographic lens was also fabricated in dichromated gelatin to verify the main characteristics of the system. The lens obtained an average first-order diffraction efficiency of 85.4% across the aperture at 532 nm.

  4. NEW OBSERVATIONS OF THE SOLAR 0.5–5 KEV SOFT X-RAY SPECTRUM

    Energy Technology Data Exchange (ETDEWEB)

    Caspi, Amir; Woods, Thomas N. [Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303 (United States); Warren, Harry P. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)

    2015-03-20

    The solar corona is orders of magnitude hotter than the underlying photosphere, but how the corona attains such high temperatures is still not understood. Soft X-ray (SXR) emission provides important diagnostics for thermal processes in the high-temperature corona, and is also an important driver of ionospheric dynamics at Earth. There is a crucial observational gap between ∼0.2 and ∼4 keV, outside the ranges of existing spectrometers. We present observations from a new SXR spectrometer, the Amptek X123-SDD, which measured the spatially integrated solar spectral irradiance from ∼0.5 to ∼5 keV, with ∼0.15 keV FWHM resolution, during sounding rocket flights on 2012 June 23 and 2013 October 21. These measurements show that the highly variable SXR emission is orders of magnitude greater than that during the deep minimum of 2009, even with only weak activity. The observed spectra show significant high-temperature (5–10 MK) emission and are well fit by simple power-law temperature distributions with indices of ∼6, close to the predictions of nanoflare models of coronal heating. Observations during the more active 2013 flight indicate an enrichment of low first-ionization potential elements of only ∼1.6, below the usually observed value of ∼4, suggesting that abundance variations may be related to coronal heating processes. The XUV Photometer System Level 4 data product, a spectral irradiance model derived from integrated broadband measurements, significantly overestimates the spectra from both flights, suggesting a need for revision of its non-flare reference spectra, with important implications for studies of Earth ionospheric dynamics driven by solar SXRs.

  5. Neuroendocrine abnormalities in hypothalamic amenorrhea: spectrum, stability, and response to neurotransmitter modulation.

    Science.gov (United States)

    Perkins, R B; Hall, J E; Martin, K A

    1999-06-01

    To characterize the neuroendocrine patterns of abnormal GnRH secretion in hypothalamic amenorrhea (HA), 49 women with primary and secondary HA underwent frequent sampling of LH in a total of 72 baseline studies over 12-24 h. A subset of women participated in more than one study to address 1) the variability of LH pulse patterns over time; and 2) the impact of modulating opioid, dopaminergic, and adrenergic tone on LH secretory patterns. The frequency and amplitude of LH secretion was compared with that seen in the early follicular phase (EFP) of normally cycling women. The spectrum of abnormalities of LH pulses was 8% apulsatile, 27% low frequency/low amplitude, 8% low amplitude/normal frequency, 43% low frequency/normal amplitude, 14% normal frequency/normal amplitude. Of patients studied overnight, 45% demonstrated a pubertal pattern of augmented LH secretion during sleep. Of patients studied repeatedly, 75% demonstrated at least 2 different patterns of LH secretion, and 33% reverted at least once to a normal pattern of secretion. An increase in LH pulse frequency was seen in 12 of 15 subjects in response to naloxone (opioid receptor antagonist). Clonidine (alpha-2 adrenergic agonist) was associated with a decrease in mean LH in 3 of 3 subjects. An increase in LH pulse frequency was seen in 4 of 8 subjects in response to metoclopramide (dopamine receptor antagonist), but the response was not statistically significant. Baseline abnormalities in LH secretion did not appear to influence response to neurotransmitter modulation. 1) HA represents a spectrum of disordered GnRH secretion that can vary over time; 2) LH pulse patterns at baseline do not appear to influence the ability to respond to neurotransmitter modulation; 3) Opioid and adrenergic tone appear to influence the hypothalamic GnRH pulse generator in some individuals with HA.

  6. Highly active GaN-stabilized Ta{sub 3}N{sub 5} thin-film photoanode for solar water oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Miao; Hisatomi, Takashi; Sasaki, Yutaka; Nakabayashi, Mamiko; Shibata, Naoya; Nishiyama, Hiroshi; Katayama, Masao; Yamada, Taro; Domen, Kazunari [School of Engineering, the University of Tokyo (Japan); Japan Technological Research Association of Artificial Photosynthetic Chemical Process, Tokyo (Japan); Suzuki, Sayaka; Teshima, Katsuya [Faculty of Engineering, Shinshu University, Nagano (Japan)

    2017-04-18

    Ta{sub 3}N{sub 5} is a very promising photocatalyst for solar water splitting because of its wide spectrum solar energy utilization up to 600 nm and suitable energy band position straddling the water splitting redox reactions. However, its development has long been impeded by poor compatibility with electrolytes. Herein, we demonstrate a simple sputtering-nitridation process to fabricate high-performance Ta{sub 3}N{sub 5} film photoanodes owing to successful synthesis of the vital TaO{sub δ} precursors. An effective GaN coating strategy is developed to remarkably stabilize Ta{sub 3}N{sub 5} by forming a crystalline nitride-on-nitride structure with an improved nitride/electrolyte interface. A stable, high photocurrent density of 8 mA cm{sup -2} was obtained with a CoPi/GaN/Ta{sub 3}N{sub 5} photoanode at 1.2 V{sub RHE} under simulated sunlight, with O{sub 2} and H{sub 2} generated at a Faraday efficiency of unity over 12 h. Our vapor-phase deposition method can be used to fabricate high-performance (oxy)nitrides for practical photoelectrochemical applications. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. VIIRS Reflective Solar Band Radiometric and Stability Evaluation Using Deep Convective Clouds

    Science.gov (United States)

    Chang, Tiejun; Xiong, Xiaoxiong; Mu, Qiaozhen

    2016-01-01

    This work takes advantage of the stable distribution of deep convective cloud (DCC) reflectance measurements to assess the calibration stability and detector difference in Visible Infrared Imaging Radiometer Suite (VIIRS) reflective bands. VIIRS Sensor Data Records (SDRs) from February 2012 to June 2015 are utilized to analyze the long-term trending, detector difference, and half angle mirror (HAM) side difference. VIIRS has two thermal emissive bands with coverage crossing 11 microns for DCC pixel identification. The comparison of the results of these two processing bands is one of the indicators of analysis reliability. The long-term stability analysis shows downward trends (up to approximately 0.4 per year) for the visible and near-infrared bands and upward trends (up to 0.5per year) for the short- and mid-wave infrared bands. The detector difference for each band is calculated as the difference relative to the average reflectance overall detectors. Except for the slightly greater than 1 difference in the two bands at 1610 nm, the detector difference is less than1 for other solar reflective bands. The detector differences show increasing trends for some short-wave bands with center wavelengths from 400 to 600 nm and remain unchanged for the bands with longer center wavelengths. The HAM side difference is insignificant and stable. Those short-wave bands from 400 to 600 nm also have relatively larger HAM side difference, up to 0.25.Comparing the striped images from SDR and the smooth images after the correction validates the analyses of detector difference and HAM side difference. These analyses are very helpful for VIIRS calibration improvement and thus enhance product quality

  8. Broadband plasmonic perfect light absorber in the visible spectrum for solar cell applications

    Science.gov (United States)

    Mudachathi, Renilkumar; Tanaka, Takuo

    2018-03-01

    The coupling of electromagnetic waves with subwavelength metal structures results in the perfect light absorption and has been extensively explored in the recent years for many possible applications like photovoltaics, sensing, photodetectors, emitters and camouflaging systems to name a few. Herein we present the design and fabrication of a broadband plasmonic light absorber using aluminum as functional material for operation in the visible frequency range. The metal structures can be tuned in size to manipulate the plasmonic resonance; thereby light absorption at any desired wavelengths could be realized. Thus the broadband light absorber in the visible spectrum is designed using metal structures of different sizes supporting non-overlapping individual resonances at regular intervals of wavelengths. The metal structures of different sizes are grouped in to a single unit cell and the absorber is fabricated by periodically arranging these unit cells in a square lattice. Light absorption of more than 90% for over a broad wavelength range of 200 nm from 425 nm to 650 nm in the visible spectrum is demonstrated.

  9. Procedures and practices for evaluating thin-film solar cell stability

    NARCIS (Netherlands)

    Roesch, R; Faber, T; von Hauff, E.L.; Brown, T. M.; Lira-Cantu, M.; Hoppe, H.

    2015-01-01

    During the last few decades, and in some cases only the last few years, novel thin-film photovoltaic (PV) technologies such as dye-sensitized solar cells (DSSC), organic solar cells (OPV), and, more recently, perovskite-based solar cells (PSC) have been growing in maturity with respect to device

  10. Polymer materials for roll coated solar cells: strategies tom improve performance and stability

    DEFF Research Database (Denmark)

    Heckler, Ilona Maria

    Solar cells are among the renewable energy technologies with a large potential in terms of solar energy availability. The solar cells based on conjugated polymers belong to the third generation of this technology and their attractive features include a fast and cheap solution‐processed production...

  11. Dynamic voltage stability of a distribution system with high penetration of grid-connected photovoltaic type solar generators

    Directory of Open Access Journals (Sweden)

    Zetty Adibah Kamaruzzaman

    2016-06-01

    Full Text Available This paper presents the impact of grid-connected photovoltaic (PV generator on dynamic voltage stability of a power distribution system by considering solar intermittency, PV penetration level, and contingencies such as line outage and load increase. The IEEE 13 node test feeder is used as a test system, and a solar PV of 0.48 kV/0.5 MVA is integrated into the test system. Test results show that system voltage is stable at high PV penetration levels. Increase in load causes voltage instability, in which voltage drops below its allowable operating limit. Thus, increase in PV penetration level does not improve system voltage stability because the system experiences voltage collapse during line outage.

  12. Enhanced planar perovskite solar cell efficiency and stability using a perovskite/PCBM heterojunction formed in one step.

    Science.gov (United States)

    Zhou, Long; Chang, Jingjing; Liu, Ziye; Sun, Xu; Lin, Zhenhua; Chen, Dazheng; Zhang, Chunfu; Zhang, Jincheng; Hao, Yue

    2018-02-08

    Perovskite/PCBM heterojunctions are efficient for fabricating perovskite solar cells with high performance and long-term stability. In this study, an efficient perovskite/PCBM heterojunction was formed via conventional sequential deposition and one-step formation processes. Compared with conventional deposition, the one-step process was more facile, and produced a perovskite thin film of substantially improved quality due to fullerene passivation. Moreover, the resulting perovskite/PCBM heterojunction exhibited more efficient carrier transfer and extraction, and reduced carrier recombination. The perovskite solar cell device based on one-step perovskite/PCBM heterojunction formation exhibited a higher maximum PCE of 17.8% compared with that from the conventional method (13.7%). The device also showed exceptional stability, retaining 83% of initial PCE after 60 days of storage under ambient conditions.

  13. A Review on Current Status of Stability and Knowledge on Liquid Electrolyte-Based Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Frédéric Sauvage

    2014-01-01

    Full Text Available The purpose of this review is to gather the current background in materials development and provide the reader with an accurate image of today’s knowledge regarding the stability of dye-sensitized solar cells. This contribution highlights the literature from the 1970s to the present day on nanostructured TiO2, dye, Pt counter electrode, and liquid electrolyte for which this review is focused on.

  14. Diagnostic stability of autism spectrum disorder in toddlers prospectively identified in a community-based setting: Behavioural characteristics and predictors of change over time.

    Science.gov (United States)

    Barbaro, Josephine; Dissanayake, Cheryl

    2017-10-01

    Autism spectrum disorder diagnoses in toddlers have been established as accurate and stable across time in high-risk siblings and clinic-referred samples. Few studies have investigated diagnostic stability in children prospective identified in community-based settings. Furthermore, there is a dearth of evidence on the individual behaviours that predict diagnostic change over time. The stability and change of autism spectrum disorder diagnoses were investigated from 24 to 48 months in 77 children drawn from the Social Attention and Communication Study. Diagnostic stability was high, with 88.3% overall stability and 85.5% autism spectrum disorder stability. The behavioural markers at 24 months that contributed to diagnostic shift off the autism spectrum by 48 months included better eye contact, more directed vocalisations, the integration of gaze and directed vocalisations/gestures and higher non-verbal developmental quotient. These four variables correctly predicted 88.7% of children into the autism spectrum disorder-stable and autism spectrum disorder-crossover groups overall, with excellent prediction for the stable group (96.2%) and modest prediction for the crossover group (44.4%). Furthermore, non-verbal developmental quotient at 24 months accounted for the significant improvement across time in 'Social Affect' scores on the Autism Diagnostic Observation Schedule for both groups and was the only unique predictor of diagnostic crossover. These findings contribute to the body of evidence on the feasibility of diagnoses at earlier ages to facilitate children's access to interventions to promote positive developmental outcomes.

  15. A Two-Dimensional Numerical Study of Hydrodynamic, Heat and Mass Transfer and Stability in a Salt Gradient Solar Pond

    Directory of Open Access Journals (Sweden)

    Ali Ben Moussa

    2012-10-01

    Full Text Available In this work, the problem of hydrodynamic, heat and mass transfer and stability in a salt gradient solar pond has been numerically studied by means of computational fluid dynamics in transient regime. The body of the simulated pond is an enclosure of height H and length L wherein an artificial salinity gradient is created in order to suppress convective motions induced by solar radiation absorption and to stabilize the solar pond during the period of operation. Here we show the distribution of velocity, temperature and salt concentration fields during energy collection and storage in a solar pond filled with water and constituted by three different salinity zones. The bottom of the pond is blackened and the free-surface is subjected to heat losses by convection, evaporation and radiation while the vertical walls are adiabatic and impermeable. The governing equations of continuity, momentum, thermal energy and mass transfer are discretized by finite–volume method in transient regime. Velocity vector fields show the presence of thin convective cells in the upper convective zone (UCZ and large convective cells in the lower convective zone (LCZ. This study shows the importance of buoyancy ratio in the decrease of temperature in the UCZ and in the preservation of high temperature in the LCZ. It shows also the importance of the thickness of Non-Convective Zone (NCZ in the reduction of the upwards heat losses.

  16. Spectral properties of plant leaves pertaining to urban landscape design of broad-spectrum solar ultraviolet radiation reduction

    Science.gov (United States)

    Yoshimura, Haruka; Zhu, Hui; Wu, Yunying; Ma, Ruijun

    2010-03-01

    Human exposure to harmful ultraviolet (UV) radiation has important public health implications. Actual human exposure to solar UV radiation depends on ambient UV irradiance, and the latter is influenced by ground reflection. In urban areas with higher reflectivity, UV exposure occurs routinely. To discover the solar UV radiation regulation mechanism of vegetation, the spectral reflectance and transmittance of plant leaves were measured with a spectrophotometer. Typically, higher plants have low leaf reflectance (around 5%) and essentially zero transmittance throughout the UV region regardless of plant species and seasonal change. Accordingly, incident UV radiation decreases to 5% by being reflected and is reduced to zero by passing through a leaf. Therefore, stratified structures of vegetation are working as another terminator of UV rays, protecting whole terrestrial ecosystems, while vegetation at waterfronts contributes to protect aquatic ecosystems. It is possible to protect the human population from harmful UV radiation by urban landscape design of tree shade and the botanical environment. Even thin but uniformly distributed canopy is effective in attenuating UV radiation. To intercept diffuse radiation, UV screening by vertical structures such as hedges should be considered. Reflectivity of vegetation is around 2%, as foliage surfaces reduce incident UV radiation via reflection, while also eliminating it by transmittance. Accordingly, vegetation reduces incident UV radiation to around 2% by reflection. Vegetation influence on ambient UV radiation is broad-spectrum throughout the UV region. Only trees provide cool UV protective shade. Urban landscapes aimed at abating urban heat islands integrated with a reduction of human UV over-exposure would contribute to mitigation of climate change.

  17. Inter-rater reliability and stability of diagnoses of autism spectrum disorder in children identified through screening at a very young age

    NARCIS (Netherlands)

    van Daalen, Emma; Kemner, Chantal; Dietz, Claudine; Swinkels, Sophie H. N.; Buitelaar, Jan K.; van Engeland, Herman

    2009-01-01

    To examine the inter-rater reliability and stability of autism spectrum disorder (ASD) diagnoses made at a very early age in children identified through a screening procedure around 14 months of age. In a prospective design, preschoolers were recruited from a screening study for ASD. The inter-rater

  18. Inter-rater reliability and stability of diagnoses of autism spectrum disorder in children identified through screening at a very young age.

    NARCIS (Netherlands)

    Daalen, E. van; Kemner, C.; Dietz, C.; Swinkels, S.H.N.; Buitelaar, J.K.; Engeland, H.M. van

    2009-01-01

    To examine the inter-rater reliability and stability of autism spectrum disorder (ASD) diagnoses made at a very early age in children identified through a screening procedure around 14 months of age. In a prospective design, preschoolers were recruited from a screening study for ASD. The inter-rater

  19. DYNAMIC STABILITY OF THE SOLAR SYSTEM: STATISTICALLY INCONCLUSIVE RESULTS FROM ENSEMBLE INTEGRATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Zeebe, Richard E., E-mail: zeebe@soest.hawaii.edu [School of Ocean and Earth Science and Technology, University of Hawaii at Manoa, 1000 Pope Road, MSB 629, Honolulu, HI 96822 (United States)

    2015-01-01

    Due to the chaotic nature of the solar system, the question of its long-term stability can only be answered in a statistical sense, for instance, based on numerical ensemble integrations of nearby orbits. Destabilization of the inner planets, leading to close encounters and/or collisions can be initiated through a large increase in Mercury's eccentricity, with a currently assumed likelihood of ∼1%. However, little is known at present about the robustness of this number. Here I report ensemble integrations of the full equations of motion of the eight planets and Pluto over 5 Gyr, including contributions from general relativity. The results show that different numerical algorithms lead to statistically different results for the evolution of Mercury's eccentricity (e{sub M}). For instance, starting at present initial conditions (e{sub M}≃0.21), Mercury's maximum eccentricity achieved over 5 Gyr is, on average, significantly higher in symplectic ensemble integrations using heliocentric rather than Jacobi coordinates and stricter error control. In contrast, starting at a possible future configuration (e{sub M}≃0.53), Mercury's maximum eccentricity achieved over the subsequent 500 Myr is, on average, significantly lower using heliocentric rather than Jacobi coordinates. For example, the probability for e{sub M} to increase beyond 0.53 over 500 Myr is >90% (Jacobi) versus only 40%-55% (heliocentric). This poses a dilemma because the physical evolution of the real system—and its probabilistic behavior—cannot depend on the coordinate system or the numerical algorithm chosen to describe it. Some tests of the numerical algorithms suggest that symplectic integrators using heliocentric coordinates underestimate the odds for destabilization of Mercury's orbit at high initial e{sub M}.

  20. Exclusion of UV-B radiation from normal solar spectrum on the growth of mung bean and maize

    International Nuclear Information System (INIS)

    Pal, M.; Sharma, A.; Abrol, Y.P.; Sengupta, U.K.

    1997-01-01

    The increase in UV-B radiation due to depletion of the ozone layer has potentially harmful effects on plant growth and performance. The bulk of these studies conducted in growth chambers, greenhouses or in the field use different types of exposure systems which may be responsible for differences in the sensitivity of a crop to UV-B radiation. A field study using selective filters to remove the UV-B portion of the solar spectrum was conducted with mung bean (a dicotyledonous C 3 plant) and maize (a monocotyledonous C 4 plant) to determine the sensitivity of these crop plants to ambient UV-B levels without disturbing the microenvironment. Mung bean was found to be sensitive to ambient UV-B levels in terms of leaf area development, plant height attained and net photosynthesis, while maize was found to be unaffected by ambient UV-B levels (22.8 |GmW cm −2 nm −1 ) found in Delhi, India (28°38′N, 77°13′E). The level of ambient UV-B radiation thus appears to be inhibitory for optimal growth of plants, especially dicotyledonous mung bean. (author)

  1. Critical analysis of stability and performance of organometal halide perovskite solar cells via various fabrication method (Review

    Directory of Open Access Journals (Sweden)

    Suhaimi Suriati

    2017-01-01

    Full Text Available Organometal halide perovskite solar cells (Omh-PSCs have attracted attention due to its unique electrical and optical properties. Ideally, the Omh-PSCs should remain free from degradation under normal operating conditions for several years, preferably tens of years. In order to produce high power conversion efficiency with low potential of degradation, different fabrication methods have been developed. The reported stability of perovskite films can vary significantly and reported to decay substantially up to 20% of its original performance. A thorough understanding of fabrication process upon the stability of the device is regarded as crucial to pave the way for future endeavors. This review summarized and highlighted the recent research of fabrication methods that gave an impact to the stability of perovskite devices.

  2. Stability and change in autism spectrum disorder diagnosis from age 3 to middle childhood in a high-risk sibling cohort.

    Science.gov (United States)

    Brian, Jessica; Bryson, Susan E; Smith, Isabel M; Roberts, Wendy; Roncadin, Caroline; Szatmari, Peter; Zwaigenbaum, Lonnie

    2016-10-01

    Considerable evidence on autism spectrum disorder emergence comes from longitudinal high-risk samples (i.e. younger siblings of children with autism spectrum disorder). Diagnostic stability to age 3 is very good when diagnosed as early as 18-24 months, but sensitivity is weaker, and relatively little is known beyond toddlerhood. We examined stability and change in blinded, clinical best-estimate diagnosis from age 3 to middle childhood (mean age = 9.5 years) in 67 high-risk siblings enrolled in infancy. Good agreement emerged for clinical best-estimate diagnoses (89.6% overall; kappa = 0.76, p autism spectrum disorder": 17 retained their autism spectrum disorder diagnosis (94.4%; 13 boys, 4 girls) and 1 no longer met autism spectrum disorder criteria at follow-up. Among "non-autism spectrum disorder" cases at age 3, 43/49 remained non-autism spectrum disorder at follow-up (87.8%; 22 boys, 21 girls) and 6/49 met lower autism symptomatology criteria ("Later-Diagnosed"; 3 boys, 3 girls). Later-diagnosed cases had significantly lower autism spectrum disorder symptomatology and higher receptive language at age 3 and trends toward lower autism symptoms and higher cognitive abilities at follow-up. Emerging developmental concerns were noted in all later-diagnosed cases, by age 3 or 5. High-risk children need to be followed up into middle childhood, particularly when showing differences in autism-related domains. © The Author(s) 2015.

  3. A dissipative model of solar system and stability of stationary rotations

    Science.gov (United States)

    Vilke, V. G.

    2009-04-01

    In classical model of Solar system the planets are represented by the material points cooperating under the law of universal gravitation. This model remains fair if planet to consider as absolutely rigid spheres with spherical distribution of density. The gravitational potential of such body coincides with potential of a material point, and rotation of each sphere concerning his centre of mass occurs to constant angular velocity. The motion of the centers of mass of spherical planets identically to motion in the appropriate problem of points. Let's notice, that forms of planets of Solar system are close to spherical as dominant forces at formation of planets are gravitational forces to which forces of molecular interaction in substance of a planet counteract. The model of the isolated Solar system submitted in a not indignant condition by homogeneous viscoelastic spheres is considered. Under action of own rotation and tidal gravitational forces the spherical planet changes the shape: there is "flattening" of a planet in a direction of a vector of its angular velocity and formation of tidal bulgs on the lines connecting the centre of a planet with the centers of other planets. From a variational principle of Hamilton the full system of the equations describing movements of the centers of mass of planets, rotations of systems of coordinates, by integrated image connected with planets, and deformations of planets be relative these of systems of coordinates has been obtained. It is supposed, that tidal gravitational, centrifugal and elastic forces result in small change of the spherical form of a planet. In system there are small parameters - inversely proportional of the Young modules of materials of the planets, providing small deformations of planets at influence on them of the centrifugal forces produced by own rotation of planets, and the small tidal deformations arising under influence of gradients of gravitational forces. The method of division of movements

  4. Optimizing P3HT/PCBM/MWCNT films for increased stability in polymer bulk heterojunction solar cells

    International Nuclear Information System (INIS)

    Singh, Vinamrita; Arora, Swati; Arora, Manoj; Sharma, Vishal; Tandon, R.P.

    2014-01-01

    The effect of multi-walled carbon nanotubes on the properties of P3HT:PCBM based solar cells has been studied. The concentration of MWCNT was optimized at 0.2% and the concentration of P3HT:PCBM was increased from 20mg/ml to 30mg/ml to obtain highest efficiency. An increase in charge carrier mobility was also observed, which is attributed to high charge transport properties of MWCNT. The active layer was optically stable with respect to absorption, whereas the emission spectra revealed an increase in charge recombination with time. The solar cells doped with MWCNT exhibited increased stability as compared to undoped cells. - Highlights: • MWCNT doped P3HT:PCBM based solar cells are optimized for increased efficiency. • Degradation studies showed that MWCNT stabilizes the cell performance. • Mobility and basic device characteristics decreased with time. • Photoluminescence studies with time showed an increase in charge recombination. • Degradation for devices kept in air is faster as compared to the samples in vacuum

  5. Optimizing P3HT/PCBM/MWCNT films for increased stability in polymer bulk heterojunction solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Vinamrita [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Arora, Swati, E-mail: drswatia@yahoo.com [Department of Physics, Zakir Husain Delhi College, University of Delhi, Delhi 110002 (India); Arora, Manoj [Department of Physics, Ramjas College, University of Delhi, Delhi 110007 (India); Sharma, Vishal; Tandon, R.P. [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

    2014-08-22

    The effect of multi-walled carbon nanotubes on the properties of P3HT:PCBM based solar cells has been studied. The concentration of MWCNT was optimized at 0.2% and the concentration of P3HT:PCBM was increased from 20mg/ml to 30mg/ml to obtain highest efficiency. An increase in charge carrier mobility was also observed, which is attributed to high charge transport properties of MWCNT. The active layer was optically stable with respect to absorption, whereas the emission spectra revealed an increase in charge recombination with time. The solar cells doped with MWCNT exhibited increased stability as compared to undoped cells. - Highlights: • MWCNT doped P3HT:PCBM based solar cells are optimized for increased efficiency. • Degradation studies showed that MWCNT stabilizes the cell performance. • Mobility and basic device characteristics decreased with time. • Photoluminescence studies with time showed an increase in charge recombination. • Degradation for devices kept in air is faster as compared to the samples in vacuum.

  6. Inter-rater reliability and stability of diagnoses of autism spectrum disorder in children identified through screening at a very young age.

    Science.gov (United States)

    van Daalen, Emma; Kemner, Chantal; Dietz, Claudine; Swinkels, Sophie H N; Buitelaar, Jan K; van Engeland, Herman

    2009-11-01

    To examine the inter-rater reliability and stability of autism spectrum disorder (ASD) diagnoses made at a very early age in children identified through a screening procedure around 14 months of age. In a prospective design, preschoolers were recruited from a screening study for ASD. The inter-rater reliability of the diagnosis of ASD was measured through an independent assessment of a randomly selected subsample of 38 patients by two other psychiatrists. The diagnoses at 23 months and 42 months of 131 patients, based on the clinical assessment and the diagnostic classifications of standardised instruments, were compared to evaluate stability of the diagnosis of ASD. Inter-rater reliability on a diagnosis of ASD versus non-ASD at 23 months was 87% with a weighted kappa of 0.74 (SE 0.11). The stability of the different diagnoses in the autism spectrum was 63% for autistic disorder, 54% for pervasive developmental disorder, not otherwise specified (PDD-NOS), and 91% for the whole category of ASD. Most diagnostic changes at 42 months were within the autism spectrum from autistic disorder to PDD-NOS and were mainly due to diminished symptom severity. Children who moved outside the ASD category at 42 months made significantly larger gains in cognitive and language skills than children with a stable ASD diagnosis. In conclusion, the inter-rater reliability and stability of the diagnoses of ASD established at 23 months in this population-based sample of very young children are good.

  7. Enhanced thermal stability of a polymer solar cell blend induced by electron beam irradiation in the transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Bäcke, Olof, E-mail: obacke@chalmers.se [Department of Applied Physics, Chalmers University of Technology, 41296 Göteborg (Sweden); Lindqvist, Camilla; Diaz de Zerio Mendaza, Amaia [Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296 Göteborg (Sweden); Gustafsson, Stefan [Department of Applied Physics, Chalmers University of Technology, 41296 Göteborg (Sweden); Wang, Ergang; Andersson, Mats R.; Müller, Christian [Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296 Göteborg (Sweden); Kristiansen, Per Magnus [Institute of Polymer Nanotechnology (INKA), FHNW University of Applied Science and Arts Northwestern Switzerland, 5210 Windisch (Switzerland); Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, 5232 Villigen (Switzerland); Olsson, Eva, E-mail: eva.olsson@chalmers.se [Department of Applied Physics, Chalmers University of Technology, 41296 Göteborg (Sweden)

    2017-05-15

    We show by in situ microscopy that the effects of electron beam irradiation during transmission electron microscopy can be used to lock microstructural features and enhance the structural thermal stability of a nanostructured polymer:fullerene blend. Polymer:fullerene bulk-heterojunction thin films show great promise for use as active layers in organic solar cells but their low thermal stability is a hindrance. Lack of thermal stability complicates manufacturing and influences the lifetime of devices. To investigate how electron irradiation affects the thermal stability of polymer:fullerene films, a model bulk-heterojunction film based on a thiophene-quinoxaline copolymer and a fullerene derivative was heat-treated in-situ in a transmission electron microscope. In areas of the film that exposed to the electron beam the nanostructure of the film remained stable, while the nanostructure in areas not exposed to the electron beam underwent large phase separation and nucleation of fullerene crystals. UV–vis spectroscopy shows that the polymer:fullerene films are stable for electron doses up to 2000 kGy. - Highlights: • Thermal stability of a polymer: fullerne blend is increased using electron irradiation. • Using in-situ transmission electron microscopy the nanostructure is studied. • Electron irradiation stops phase separation between the polymer and fullerene. • Electron irradiation quenches the formation and nucleation of fullerene crystals.

  8. Toward Improved Lifetimes of Organic Solar Cells under Thermal Stress: Substrate-Dependent Morphological Stability of PCDTBT:PCBM Films and Devices.

    Science.gov (United States)

    Li, Zhe; Ho Chiu, Kar; Shahid Ashraf, Raja; Fearn, Sarah; Dattani, Rajeev; Cheng Wong, Him; Tan, Ching-Hong; Wu, Jiaying; Cabral, João T; Durrant, James R

    2015-10-15

    Morphological stability is a key requirement for outdoor operation of organic solar cells. We demonstrate that morphological stability and lifetime of polymer/fullerene based solar cells under thermal stress depend strongly on the substrate interface on which the active layer is deposited. In particular, we find that the stability of benchmark PCDTBT/PCBM solar cells under modest thermal stress is substantially increased in inverted solar cells employing a ZnO substrate compared to conventional devices employing a PSS substrate. This improved stability is observed to correlate with PCBM nucleation at the 50 nm scale, which is shown to be strongly influenced by different substrate interfaces. Employing this approach, we demonstrate remarkable thermal stability for inverted PCDTBT:PC70BM devices on ZnO substrates, with negligible (humidity exposure as widely reported previously, can also demonstrate enhanced morphological stability. As such we show that the choice of suitable substrate interfaces may be a key factor in achieving prolonged lifetimes for organic solar cells under thermal stress conditions.

  9. Improved Efficiency and Stability of Perovskite Solar Cells Induced by CO Functionalized Hydrophobic Ammonium-Based Additives.

    Science.gov (United States)

    Wu, Zhifang; Raga, Sonia R; Juarez-Perez, Emilio J; Yao, Xuyang; Jiang, Yan; Ono, Luis K; Ning, Zhijun; Tian, He; Qi, Yabing

    2018-01-01

    Because of the rapid rise of the efficiency, perovskite solar cells are currently considered as the most promising next-generation photovoltaic technology. Much effort has been made to improve the efficiency and stability of perovskite solar cells. Here, it is demonstrated that the addition of a novel organic cation of 2-(6-bromo-1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)ethan-1-ammonium iodide (2-NAM), which has strong Lewis acid and base interaction (between CO and Pb) with perovskite, can effectively increase crystalline grain size and reduce charge carrier recombination of the double cation FA 0.83 MA 0.17 PbI 2.51 Br 0.49 perovskite film, thus boosting the efficiency from 17.1 ± 0.8% to 18.6 ± 0.9% for the 0.1 cm 2 cell and from 15.5 ± 0.5% to 16.5 ± 0.6% for the 1.0 cm 2 cell. The champion cell shows efficiencies of 20.0% and 17.6% with active areas of 0.1 and 1.0 cm 2 , respectively. Moreover, the hysteresis behavior is suppressed and the stability is improved. The result provides a promising route to further elevate efficiency and stability of perovskite solar cells by the fine tuning of triple organic cations. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Orbit Stability of OSIRIS-REx in the Vicinity of Bennu Using a High-Fidelity Solar Radiation Model

    Science.gov (United States)

    Williams, Trevor; Hughes, Kyle; Mashiku, Alinda; Longuski, James

    2015-01-01

    The OSIRIS-REx mission (Origins Spectral Interpretation Resource Identification Security Regolith EXPlorer) is an asteroid sample return mission to Bennu (RQ36) that is scheduled to launch in 2016. The planned science operations precluding the small retrieval involve operations in terminator orbits (orbit plane is perpendicular to the sun). Over longer durations the solar radiation pressure (SRP) perturbs the orbit causing it to precess. Our work involves: modeling high fidelity SRP model to capture the perturbations during attitude changes; design a stable orbit from the high fidelity models to analyze the stability over time.

  11. Edge sealing for low cost stability enhancement of roll-to-roll processed flexible polymer solar cell modules

    DEFF Research Database (Denmark)

    Tanenbaum, David M.; Dam, Henrik Friis; Rösch, R.

    2012-01-01

    Fully roll-to-roll processed polymer solar cell modules were prepared, characterized, and laminated. Cell modules were cut from the roll and matched pairs were selected, one module with exposed cut edges, the other laminated again with the same materials and adhesive sealing fully around the cut...... edges. The edge sealing rim was 10 mm wide. Cell modules were characterized by periodic measurements of IV curves over extended periods in a variety of conditions, as well as by a variety of spatial imaging techniques. Data show significant stability benefits of the edge sealing process. The results...

  12. Crosslinked Remote-Doped Hole-Extracting Contacts Enhance Stability under Accelerated Lifetime Testing in Perovskite Solar Cells.

    Science.gov (United States)

    Xu, Jixian; Voznyy, Oleksandr; Comin, Riccardo; Gong, Xiwen; Walters, Grant; Liu, Min; Kanjanaboos, Pongsakorn; Lan, Xinzheng; Sargent, Edward H

    2016-04-13

    A crosslinked hole-extracting electrical contact is reported, which simultaneously improves the stability and lowers the hysteresis of perovskite solar cells. Polymerizable monomers and crosslinking processes are developed to obviate in situ degradation of the under lying perovskite. The crosslinked material is band-aligned with perovskite. The required free carrier density is induced by a high-work-function metal oxide layer atop the device, following a remote-doping strategy. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. The Influence of Conjugated Polymer Side Chain Manipulation on the Efficiency and Stability of Polymer Solar Cells

    DEFF Research Database (Denmark)

    Heckler, Ilona Maria; Kesters, Jurgen; Defour, Maxime

    2016-01-01

    ]thiazole (TzTz) acceptor units, were selected toward effective device scalability by roll-coating. The influence of the partial exchange (5% or 10%) of the solubilizing 2-hexyldecyloxy by alternative 2-phenylethoxy groups on efficiency and stability was investigated. With an increasing 2-phenylethoxy ratio...... studies under constant sun irradiance showed a diminishing initial degradation rate for the BT-based devices upon including the alternative side chains, whereas the (more stable) TzTz-based devices degraded at a faster rate from the start of the experiment upon partly exchanging the side chains. No clear......The stability of polymer solar cells (PSCs) can be influenced by the introduction of particular moieties on the conjugated polymer side chains. In this study, two series of donor-acceptor copolymers, based on bis(thienyl)dialkoxybenzene donor and benzo[c][1,2,5]thiadiazole (BT) or thiazolo[5,4-d...

  14. The Function of TiO2 with Respect to Sensitizer Stability in Nanocrystalline Dye Solar Cells

    Directory of Open Access Journals (Sweden)

    A. Barkschat

    2008-01-01

    Full Text Available Dyes of characteristically different composition have been tested with respect to long-term stability in operating standardized dye sensitized cells during a time period of up to 3600 hours. Selective solar illumination, the use of graded filters, and imaging of photocurrents revealed that degradation is linked to the density of photocurrent passed. Photoelectrochemical degradation was observed with all sensitizers investigated. Sensitization was less efficient and sensitizers were less photostable with nanostructured ZnO compared to nanostructured TiO2. The best performance was confirmed for cis-RuII(dcbpyH22(NCS2 on TiO2. However, it was 7–10 times less stable under other identical conditions on ZnO. Stability is favored by carboxylate anchoring and metal-centred electron transfer. In presence of TiO2, it is enhanced by formation of a stabilizing charge-transfer complex between oxidized Ru dye and back-bonding interfacial Ti3+ states. This is considered to be the main reason for the ongoing use of expensive Ru complexes in combination with TiO2. The local surface chemistry of the nanocrystalline TiO2 turned out to be a crucial factor for sensitizer stability and requires further investigation.

  15. Enhanced thermal stability of a polymer solar cell blend induced by electron beam irradiation in the transmission electron microscope.

    Science.gov (United States)

    Bäcke, Olof; Lindqvist, Camilla; de Zerio Mendaza, Amaia Diaz; Gustafsson, Stefan; Wang, Ergang; Andersson, Mats R; Müller, Christian; Kristiansen, Per Magnus; Olsson, Eva

    2017-05-01

    We show by in situ microscopy that the effects of electron beam irradiation during transmission electron microscopy can be used to lock microstructural features and enhance the structural thermal stability of a nanostructured polymer:fullerene blend. Polymer:fullerene bulk-heterojunction thin films show great promise for use as active layers in organic solar cells but their low thermal stability is a hindrance. Lack of thermal stability complicates manufacturing and influences the lifetime of devices. To investigate how electron irradiation affects the thermal stability of polymer:fullerene films, a model bulk-heterojunction film based on a thiophene-quinoxaline copolymer and a fullerene derivative was heat-treated in-situ in a transmission electron microscope. In areas of the film that exposed to the electron beam the nanostructure of the film remained stable, while the nanostructure in areas not exposed to the electron beam underwent large phase separation and nucleation of fullerene crystals. UV-vis spectroscopy shows that the polymer:fullerene films are stable for electron doses up to 2000kGy. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Stability issues of conjugated polymer / fullerene solar cells from a chemical viewpoint

    NARCIS (Netherlands)

    Hummelen, J.C.; Knol, J.; Sánchez, L.

    2001-01-01

    The efficiency of energy conversion and the stability or lifetime of ‘plastic’ photovoltaic cells, based on conjugated polymer/ fullerene blends, are the two main issues to be improved for this type of devices. The stability of these PV cells depends potentially on a large number of factors. A brief

  17. An evaluation of a solar radiation/delta-T method for estimating Pasquill-Gifford (P-G) stability categories

    Energy Technology Data Exchange (ETDEWEB)

    Coulter, C.T. [Environmental Protection Agency, Research Triangle Park, NC (United States)

    1994-12-31

    There has been a continuing need to develop robust methods for determining Pasquill-Gifford (P-G) stability categories using solely on-site meteorological instrumentation. The Revised EPA Guideline on Air Quality Models recommends several such methods. Experience with these suggests that, since they rely on turbulence measurements, they can be unduly influenced by local effects such as mesoscale circulation (e.g., upslope/downslope flows, land/sea breeze), wakes from tree barriers or buildings, etc. to such an extent as to diminish their practical usefulness. In the following discussion, a methodology is proposed for estimating P-G stability categories that employs on-site meteorological measurements (10m wind speed coupled with solar radiation during the day and temperature difference, {Delta}T, at night) in lieu of cloud cover and ceiling height observations. The proposed method was adapted from Bowen and is herein referred to as the solar radiation/delta-T (SRDT) method. To evaluate the method, an attempt was made to acquire data bases from diverse geographical areas. Data bases with {Delta}T measurements from 2-10m above ground level were of primary interest for characterizing the boundary layer; other intervals were considered for evaluation, as available. To document the consequence of implementing the method in practical applications, an analysis was needed of the effect on design concentration ratios.

  18. The Influence of Conjugated Polymer Side Chain Manipulation on the Efficiency and Stability of Polymer Solar Cells.

    Science.gov (United States)

    Heckler, Ilona M; Kesters, Jurgen; Defour, Maxime; Madsen, Morten V; Penxten, Huguette; D'Haen, Jan; Van Mele, Bruno; Maes, Wouter; Bundgaard, Eva

    2016-03-09

    The stability of polymer solar cells (PSCs) can be influenced by the introduction of particular moieties on the conjugated polymer side chains. In this study, two series of donor-acceptor copolymers, based on bis(thienyl)dialkoxybenzene donor and benzo[ c ][1,2,5]thiadiazole (BT) or thiazolo[5,4- d ]thiazole (TzTz) acceptor units, were selected toward effective device scalability by roll-coating. The influence of the partial exchange (5% or 10%) of the solubilizing 2-hexyldecyloxy by alternative 2-phenylethoxy groups on efficiency and stability was investigated. With an increasing 2-phenylethoxy ratio, a decrease in solar cell efficiency was observed for the BT-based series, whereas the efficiencies for the devices based on the TzTz polymers remained approximately the same. The photochemical degradation rate for PSCs based on the TzTz polymers decreased with an increasing 2-phenylethoxy ratio. Lifetime studies under constant sun irradiance showed a diminishing initial degradation rate for the BT-based devices upon including the alternative side chains, whereas the (more stable) TzTz-based devices degraded at a faster rate from the start of the experiment upon partly exchanging the side chains. No clear trends in the degradation behavior, linked to the copolymer structural changes, could be established at this point, evidencing the complex interplay of events determining PSCs' lifetime.

  19. The Influence of Conjugated Polymer Side Chain Manipulation on the Efficiency and Stability of Polymer Solar Cells

    Directory of Open Access Journals (Sweden)

    Ilona M. Heckler

    2016-03-01

    Full Text Available The stability of polymer solar cells (PSCs can be influenced by the introduction of particular moieties on the conjugated polymer side chains. In this study, two series of donor-acceptor copolymers, based on bis(thienyldialkoxybenzene donor and benzo[c][1,2,5]thiadiazole (BT or thiazolo[5,4-d]thiazole (TzTz acceptor units, were selected toward effective device scalability by roll-coating. The influence of the partial exchange (5% or 10% of the solubilizing 2-hexyldecyloxy by alternative 2-phenylethoxy groups on efficiency and stability was investigated. With an increasing 2-phenylethoxy ratio, a decrease in solar cell efficiency was observed for the BT-based series, whereas the efficiencies for the devices based on the TzTz polymers remained approximately the same. The photochemical degradation rate for PSCs based on the TzTz polymers decreased with an increasing 2-phenylethoxy ratio. Lifetime studies under constant sun irradiance showed a diminishing initial degradation rate for the BT-based devices upon including the alternative side chains, whereas the (more stable TzTz-based devices degraded at a faster rate from the start of the experiment upon partly exchanging the side chains. No clear trends in the degradation behavior, linked to the copolymer structural changes, could be established at this point, evidencing the complex interplay of events determining PSCs’ lifetime.

  20. Flexible high power-per-weight perovskite solar cells with chromium oxide-metal contacts for improved stability in air

    Science.gov (United States)

    Kaltenbrunner, Martin; Adam, Getachew; Głowacki, Eric Daniel; Drack, Michael; Schwödiauer, Reinhard; Leonat, Lucia; Apaydin, Dogukan Hazar; Groiss, Heiko; Scharber, Markus Clark; White, Matthew Schuette; Sariciftci, Niyazi Serdar; Bauer, Siegfried

    2015-10-01

    Photovoltaic technology requires light-absorbing materials that are highly efficient, lightweight, low cost and stable during operation. Organolead halide perovskites constitute a highly promising class of materials, but suffer limited stability under ambient conditions without heavy and costly encapsulation. Here, we report ultrathin (3 μm), highly flexible perovskite solar cells with stabilized 12% efficiency and a power-per-weight as high as 23 W g-1. To facilitate air-stable operation, we introduce a chromium oxide-chromium interlayer that effectively protects the metal top contacts from reactions with the perovskite. The use of a transparent polymer electrode treated with dimethylsulphoxide as the bottom layer allows the deposition--from solution at low temperature--of pinhole-free perovskite films at high yield on arbitrary substrates, including thin plastic foils. These ultra-lightweight solar cells are successfully used to power aviation models. Potential future applications include unmanned aerial vehicles--from airplanes to quadcopters and weather balloons--for environmental and industrial monitoring, rescue and emergency response, and tactical security applications.

  1. Light and Electrically Induced Phase Segregation and Its Impact on the Stability of Quadruple Cation High Bandgap Perovskite Solar Cells.

    Science.gov (United States)

    Duong, The; Mulmudi, Hemant Kumar; Wu, YiLiang; Fu, Xiao; Shen, Heping; Peng, Jun; Wu, Nandi; Nguyen, Hieu T; Macdonald, Daniel; Lockrey, Mark; White, Thomas P; Weber, Klaus; Catchpole, Kylie

    2017-08-16

    Perovskite material with a bandgap of 1.7-1.8 eV is highly desirable for the top cell in a tandem configuration with a lower bandgap bottom cell, such as a silicon cell. This can be achieved by alloying iodide and bromide anions, but light-induced phase-segregation phenomena are often observed in perovskite films of this kind, with implications for solar cell efficiency. Here, we investigate light-induced phase segregation inside quadruple-cation perovskite material in a complete cell structure and find that the magnitude of this phenomenon is dependent on the operating condition of the solar cell. Under short-circuit and even maximum power point conditions, phase segregation is found to be negligible compared to the magnitude of segregation under open-circuit conditions. In accordance with the finding, perovskite cells based on quadruple-cation perovskite with 1.73 eV bandgap retain 94% of the original efficiency after 12 h operation at the maximum power point, while the cell only retains 82% of the original efficiency after 12 h operation at the open-circuit condition. This result highlights the need to have standard methods including light/dark and bias condition for testing the stability of perovskite solar cells. Additionally, phase segregation is observed when the cell was forward biased at 1.2 V in the dark, which indicates that photoexcitation is not required to induce phase segregation.

  2. A broad-spectrum sunscreen prevents cumulative damage from repeated exposure to sub-erythemal solar ultraviolet radiation representative of temperate latitudes.

    Science.gov (United States)

    Seité, S; Christiaens, F; Bredoux, C; Compan, D; Zucchi, H; Lombard, D; Fourtanier, A; Young, A R

    2010-02-01

    We have previously shown the detrimental effects of 19 sub-erythemal exposures to daily ultraviolet radiation (DUVR, which mimics non-extreme exposure conditions), delivered over 4 weeks to volunteers. This source had UVA (320-400 nm) to UVB (290-320 nm) irradiance ratio of 25, instead of that close to 10 that is typically the case with solar-simulated radiation (SSR) that represents summer global sunlight with a clear sky and quasi-zenith solar irradiance. Here, we report on an extension of this previous study, in which we evaluated the photoprotection afforded by a broad-spectrum daily-care product with a low-sun protection factor (SPF 8, UVA-PF 7 and 3* rated UVA protection). We assessed cellular and molecular markers of photodamage that are relevant to skin cancer and photoageing. This study shows that biological effects of repeated exposure to DUVR can be prevented by a broad-spectrum daily-care product and that the level of protection afforded varies with the studied endpoint. Efficient daily UVR protection, as provided by a broad-spectrum daily-care product, is necessary to prevent the 'silent' sub-erythemal cumulative effects of UVR from inadvertent sun exposure.

  3. Improving the Operational Stability of PBDTTTz-4 Polymer Solar Cells Modules by Electrode Modification

    DEFF Research Database (Denmark)

    Roth, Bérenger; Benatto, Gisele Alves dos Reis; Corazza, Michael

    2016-01-01

    PBDTTTz-4 is employed in the ambient manufacturing of fully Roll-to-Roll organic solar cell modules. Modules are manufactured using a novel silver nanowire electrode or a previously reported carbon electrode. The average PCE of carbon modules (3.07%) and AgNW modules (1.46%) shows that PBDTTTz-4...

  4. Stability and photodegradation mechanisms of conjugated polymer/fullerene plastic solar cells

    NARCIS (Netherlands)

    Neugebauer, H.; Brabec, C.; Hummelen, J.C.; Sariciftci, N.S.

    2000-01-01

    Degradation studies of poly(2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene-vinylene) (MDMO-PPV), fullerenes ((6,6)-phenyl C-61-butyric acid methyl ester (PCBM) and C-60), and mixtures, which are the photoactive components in plastic solar cells, are shown. The degradation processes of the

  5. Shelf life stability comparison in air for solution processed pristine PDPP3T polymer and doped spiro-OMeTAD as hole transport layer for perovskite solar cell

    Directory of Open Access Journals (Sweden)

    Ashish Dubey

    2016-06-01

    Full Text Available This data in brief includes forward and reverse scanned current density–voltage (J–V characteristics of perovskite solar cells with PDPP3T and spiro-OMeTAD as HTL, stability testing conditions of perovskite solar cell shelf life in air for both PDPP3T and spiro-OMeTAD as HTL as per the description in Ref. [1], and individual J–V performance parameters acquired with increasing time exposed in ambient air are shown for both type of devices using PDPP3T and spiro-OMeTAD as HTL. The data collected in this study compares the device stability with time for both PDPP3T and spiro-OMeTAD based perovskite solar cells and is directly related to our research article “solution processed pristine PDPP3T polymer as hole transport layer for efficient perovskite solar cells with slower degradation” [2].

  6. Improving the long-term stability of PBDTTPD polymer solar cells through material purification aimed at removing organic impurities

    KAUST Repository

    Mateker, William R.; Douglas, Jessica D.; Cabanetos, Clement; Sachs-Quintana, I. T.; Bartelt, Jonathan A.; Hoke, Eric T.; El Labban, Abdulrahman; Beaujuge, Pierre; Frechet, Jean; McGehee, Michael D.

    2013-01-01

    While bulk heterojunction (BHJ) solar cells fabricated from high M n PBDTTPD achieve power conversion efficiencies (PCE) as high as 7.3%, the short-circuit current density (JSC) of these devices can drop by 20% after seven days of storage in the dark and under inert conditions. This degradation is characterized by the appearance of S-shape features in the reverse bias region of current-voltage (J-V) curves that increase in amplitude over time. Conversely, BHJ solar cells fabricated from low Mn PBDTTPD do not develop S-shaped J-V curves. However, S-shapes identical to those observed in high Mn PBDTTPD solar cells can be induced in low M n devices through intentional contamination with the TPD monomer. Furthermore, when high Mn PBDTTPD is purified via size exclusion chromatography (SEC) to reduce the content of low molecular weight species, the JSC of polymer devices is significantly more stable over time. After 111 days of storage in the dark under inert conditions, the J-V curves do not develop S-shapes and the JSC degrades by only 6%. The S-shape degradation feature, symptomatic of low device lifetimes, appears to be linked to the presence of low molecular weight contaminants, which may be trapped within samples of high Mn polymer that have not been purified by SEC. Although these impurities do not affect initial device PCE, they significantly reduce device lifetime, and solar cell stability is improved by increasing the purity of the polymer materials. © 2013 The Royal Society of Chemistry.

  7. Design and optimization of cascaded DCG based holographic elements for spectrum-splitting PV systems

    Science.gov (United States)

    Wu, Yuechen; Chrysler, Benjamin; Pelaez, Silvana Ayala; Kostuk, Raymond K.

    2017-09-01

    In this work, the technique of designing and optimizing broadband volume transmission holograms using dichromate gelatin (DCG) is summarized for solar spectrum-splitting application. Spectrum splitting photovoltaic system uses a series of single bandgap PV cells that have different spectral conversion efficiency properties to more fully utilize the solar spectrum. In such a system, one or more high performance optical filters are usually required to split the solar spectrum and efficiently send them to the corresponding PV cells. An ideal spectral filter should have a rectangular shape with sharp transition wavelengths. DCG is a near ideal holographic material for solar applications as it can achieve high refractive index modulation, low absorption and scattering properties and long-term stability to solar exposure after sealing. In this research, a methodology of designing and modeling a transmission DCG hologram using coupled wave analysis for different PV bandgap combinations is described. To achieve a broad diffraction bandwidth and sharp cut-off wavelength, a cascaded structure of multiple thick holograms is described. A search algorithm is also developed to optimize both single and two-layer cascaded holographic spectrum splitters for the best bandgap combinations of two- and three-junction SSPV systems illuminated under the AM1.5 solar spectrum. The power conversion efficiencies of the optimized systems under the AM1.5 solar spectrum are then calculated using the detailed balance method, and shows an improvement compared with tandem structure.

  8. Addendum to: ''The SNO solar neutrino data, neutrinoless double beta-decay and neutrino mass spectrum'' [Phys. Lett. B 544 (2002) 239

    International Nuclear Information System (INIS)

    Pascoli, S.; Petcov, S.T.

    2004-01-01

    We update our earlier study [Phys. Lett. B 544 (2002) 239], which was inspired by the 2002 SNO data, on the implications of the results of the solar neutrino experiments for the predictions of the effective Majorana mass in neutrinoless double beta-decay, vertical bar vertical bar. We obtain predictions for vertical bar vertical bar using the values of the neutrino oscillation parameters, obtained in the analyzes of the presently available solar neutrino data, including the just published data from the salt phase of the SNO experiment, the atmospheric neutrino and CHOOZ data and the first data from the KamLAND experiment. The main conclusion reached in the previous study [Phys. Lett. B 544 (2002) 239] of the existence of significant lower bounds on vertical bar vertical bar in the cases of neutrino mass spectrum of inverted hierarchical (IH) and quasi-degenerate (QD) type is strongly reinforced by fact that combined solar neutrino data (i) exclude the possibility of cos2θ o =0 at more than 5 s.d., (ii) determine as a best fit value cos2θ o =0.40, and (iii) imply at 95% C.L. that cos2θ o ∼>0.22, θ o being the solar neutrino mixing angle. For the IH and QD spectra we get using, e.g., the 90% C.L. allowed ranges of values of the oscillation parameters, vertical bar vertical bar ∼>0.010 eV and vertical bar vertical bar ∼>0.043 eV, respectively. We also comment on the possibility to get information on the neutrino mass spectrum and on the CP-violation in the lepton sector due to Majorana CP-violating phases

  9. H and K (Ca II) emissions as observed in coronal spectrum in the July 20, 1963 solar eclipse

    International Nuclear Information System (INIS)

    Cavallini, F.; Righini, A.

    1975-01-01

    From a detailed analysis of a coronal spectrum taken from a DC-8 jet airplane during the Eclipse of 20 July, 1963 a rough model of a coronal cold region (T approximately 10 5 K) has been obtained. The model explains the presence of the abnormal H and K (Ca II) emissions and the large amount of F corona present in the spectrum. (Auth.)

  10. Stability assessment on a 3% bilayer PbS/ZnO quantum dot heterojunction solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Luther, Joseph M.; Lloyd, Matthew T.; Beard, Matthew C. [National Renewable Energy Laboratory, Golden, CO (United States); Gao, Jianbo [National Renewable Energy Laboratory, Golden, CO (United States); University of Toledo, Toledo, OH (United States); Semonin, Octavi E.; Nozik, Arthur J. [National Renewable Energy Laboratory, Golden, CO (United States); University of Colorado, Boulder, CO (United States)

    2010-09-01

    We provide the first NREL-certified efficiency measurement on an all-inorganic, solution-processed, nanocrystal solar cell. The 3% efficient device is composed of ZnO nanocrystals and 1.3 eV PbS quantum dots with gold as the top contact. This configuration yields a stable device, retaining 95% of the starting efficiency after a 1000-hour light soak in air without encapsulation. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  11. Advanced controls for stability assessment of solar dynamics space power generation

    Science.gov (United States)

    Momoh, James A.; Anwah, Nnamdi A.

    1995-01-01

    In support of the power requirements for the Space Station Alpha (SSA), a joint program by the U.S. and Russia for a permanently manned space station to be launched into orbit by 1998, a robust control scheme is needed to assure the stability of the rotating machines that will be integrated into the power subsystem. A framework design and systems studies for modeling and analysis is presented. It employs classical d-q axes machine model with voltage/frequency dependent loads. To guarantee that design requirements and necessary trade studies are done, a functional analysis tool CORE is used for the study. This provides us with different control options for stability assessment. Initial studies and recommendations using advanced simulation tools are also presented. The benefits of the stability/control scheme for evaluating future designs and power management are discussed.

  12. Stabilization

    Directory of Open Access Journals (Sweden)

    Muhammad H. Al-Malack

    2016-07-01

    Full Text Available Fuel oil flyash (FFA produced in power and water desalination plants firing crude oils in the Kingdom of Saudi Arabia is being disposed in landfills, which increases the burden on the environment, therefore, FFA utilization must be encouraged. In the current research, the effect of adding FFA on the engineering properties of two indigenous soils, namely sand and marl, was investigated. FFA was added at concentrations of 5%, 10% and 15% to both soils with and without the addition of Portland cement. Mixtures of the stabilized soils were thoroughly evaluated using compaction, California Bearing Ratio (CBR, unconfined compressive strength (USC and durability tests. Results of these tests indicated that stabilized sand mixtures could not attain the ACI strength requirements. However, marl was found to satisfy the ACI strength requirement when only 5% of FFA was added together with 5% of cement. When the FFA was increased to 10% and 15%, the mixture’s strength was found to decrease to values below the ACI requirements. Results of the Toxicity Characteristics Leaching Procedure (TCLP, which was performed on samples that passed the ACI requirements, indicated that FFA must be cautiously used in soil stabilization.

  13. Dual Function Additives: A Small Molecule Crosslinker for Enhanced Efficiency and Stability in Organic Solar Cells

    KAUST Repository

    Rumer, Joseph W.; Ashraf, Raja S.; Eisenmenger, Nancy D.; Huang, Zhenggang; Meager, Iain; Nielsen, Christian B.; Schroeder, Bob C.; Chabinyc, Michael L.; McCulloch, Iain

    2015-01-01

    A bis-azide-based small molecule crosslinker is synthesized and evaluated as both a stabilizing and efficiency-boosting additive in bulk heterojunction organic photovoltaic cells. Activated by a noninvasive and scalable solution processing technique, polymer:fullerene blends exhibit improved thermal stability with suppressed polymer skin formation at the cathode and frustrated fullerene aggregation on ageing, with initial efficiency increased from 6% to 7%. © 2015 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Dual Function Additives: A Small Molecule Crosslinker for Enhanced Efficiency and Stability in Organic Solar Cells

    KAUST Repository

    Rumer, Joseph W.

    2015-02-01

    A bis-azide-based small molecule crosslinker is synthesized and evaluated as both a stabilizing and efficiency-boosting additive in bulk heterojunction organic photovoltaic cells. Activated by a noninvasive and scalable solution processing technique, polymer:fullerene blends exhibit improved thermal stability with suppressed polymer skin formation at the cathode and frustrated fullerene aggregation on ageing, with initial efficiency increased from 6% to 7%. © 2015 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Cable Stability

    Energy Technology Data Exchange (ETDEWEB)

    Bottura, L [European Organization for Nuclear Research, Geneva (Switzerland)

    2014-07-01

    Superconductor stability is at the core of the design of any successful cable and magnet application. This chapter reviews the initial understanding of the stability mechanism, and reviews matters of importance for stability such as the nature and magnitude of the perturbation spectrum and the cooling mechanisms. Various stability strategies are studied, providing criteria that depend on the desired design and operating conditions.

  16. Double perovskites overtaking the single perovskites: A set of new solar harvesting materials with much higher stability and efficiency

    Science.gov (United States)

    Kangsabanik, Jiban; Sugathan, Vipinraj; Yadav, Anuradha; Yella, Aswani; Alam, Aftab

    2018-05-01

    Solar energy plays an important role in substituting the ever declining source of fossil fuel energy. Finding novel materials for solar cell applications is an integral part of photovoltaic research. Hybrid lead halide perovskites are one of, if not the most, well sought material in the photovoltaic research community. Its unique intrinsic properties, flexible synthesis techniques, and device fabrication architecture made the community highly buoyant over the past few years. Yet, there are two fundamental issues that still remain a concern, i.e., the stability in external environment and the toxicity due to Pb. This led to a search for alternative materials. More recently, double perovskite [A2B B'X6 (X =Cl, Br, I)] materials have emerged as a promising choice. Few experimental synthesis and high throughput computational studies have been carried out to check for promising candidates of this class. The main outcome from these studies, however, can essentially be summarized into two categories: (i) either they have an indirect band gap or (ii) a direct but large optical band gap, which is not suitable for solar devices. Here we propose a large set of stable double perovskite materials, Cs2B B 'X6 (X =Cl, Br, I), which show indirect to direct band gap transition via small Pb+2 doping at both B and B'sites. This is done by careful band (orbital) engineering using first-principles calculations. This kind of doping has helped to change the topology of the band structure, triggering an indirect to direct transition that is optically allowed. It also reduces the band gap significantly, bringing it well into the visible region. We also simulated the optical absorption spectra of these systems and found a comparable/higher absorption coefficient and solar efficiency with respect to the state of the art photovoltaic absorber material CH3NH3PbI3 . A number of materials Cs2(B0.75Pb0.25) (B0.75'Pb0.25) X6 (for various combinations of B ,B ', and X ) are found to be promising

  17. Stability of Cu(In,Ga)Se2 solar cells: A literature review

    NARCIS (Netherlands)

    Theelen, M.; Daume, F.

    2016-01-01

    As Cu(In,Ga)Se2 (CIGS) photovoltaic (PV) technology matures to production on an industrial scale, its long-term stability becomes increasingly important: The electric yield and thus the revenue of a PV system depend on both the initial conversion efficiency as well as its development over time.

  18. Thermally reactive Thiazolo[5,4-d]thiazole based copolymers for high photochemical stability in polymer solar cells

    DEFF Research Database (Denmark)

    Helgesen, Martin; Vesterager Madsen, Morten; Andreasen, Birgitta

    2011-01-01

    New thermally reactive copolymers based on dithienylthiazolo[5,4-d]thiazole (DTZ) and silolodithiophene (SDT) have been synthesized and explored in bulk heterojunction solar cells as mixtures with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). In thin films the polymers had optical band gaps...... in the range of 1.64-1.80 eV. For solubility the polymers have incorporated alkyl groups on the SDT unit and thermally removable ester groups on the DTZ unit that can be eliminated around 200 °C for improved photochemical stability in thin films. The bulkiness of the alkyl chains on the SDT unit proved...... to be very significant in terms of photovoltaic performance of the polymer:PCBM solar cells. Polymers based on 4,4-dihexyl-4H-silolo[3,2-b:4,5-b′]dithiophene reached power conversion efficiencies (PCEs) up to 1.45% but changing the alkyl groups to more bulky ethylhexyl chains reduced the PCE to 1.17%. More...

  19. Doping, Ionic Conductivity and Photothermal Stability of Functionalized DNA for Solar Energy Conversion and Electrochromic Applications

    Science.gov (United States)

    2011-06-01

    and coworkers 1,2,3,4 . They are renewable and biodegradable materials, recovered from waste in food industry (fruits, animal and fish meat waste) and...charges leads to the change of its absorption spectrum, or in other words to a change of its color . However in most cases the electrolyte used is in...electrodes (cf. Fig. 25). CeO2- TiO2 BK7 BK7 SOLID ELECTROLYTE ITO WO3 ITO Fig. 25. Structure of the used electrochromic cell 21 Figure 26

  20. Effect of a cathode buffer layer on the stability of organic solar cells

    International Nuclear Information System (INIS)

    Wang, Danbei; Zeng, Wenjin; Chen, Shilin; Su, Xiaodan; Wang, Jin; Zhang, Hongmei

    2015-01-01

    We present the effect of a cathode buffer layer on the performance and stability of organic photovoltaics (OPVs) based on a blend of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM). Six kinds of cathode buffer layers, i.e. lithium fluoride, sodium chloride, NaCl/Mg, tris-(8-hydroxy-quinoline) aluminum, bathocuproine and 1,3,5-tris(2-N-phenylbenzimidazolyl)benzene, were inserted between the photoactive layer and an Al cathode, which played a dominant role in the device’s performance. Devices with the cathode buffer layers above exhibited improved performance. The degradation of these devices with encapsulation was further investigated in an inert atmosphere. The results indicated that devices with inorganic cathode buffer layers exhibited better stability than those with organic cathode buffer layers. (paper)

  1. Round-Robin Studies on Roll-Processed ITO-free Organic Tandem Solar Cells Combined with Inter-Laboratory Stability Studies

    DEFF Research Database (Denmark)

    Livi, Francesco; Søndergaard, Roar R.; Andersen, Thomas Rieks

    2015-01-01

    Roll-processed, indium tin oxide (ITO)-free, flexible, organic tandem solar cells and modules have been realized and used in round-robin studies as well as in parallel inter-laboratory stability studies. The tandem cells/modules show no significant difference in comparison to their single...

  2. New Low-Bandgap Materials with Good Stabilities and Efficiencies Comparable to P3HT in R2R-Coated Solar Cells

    DEFF Research Database (Denmark)

    Søndergaard, Roar; Manceau, Matthieu; Jørgensen, Mikkel

    2012-01-01

    Roll-to-roll coated organic solar cells of two new polymers processed in ambient conditions show good photochemical stabilities, and their efficiencies are comparable to similar roll-to-roll coated P3HT cells. Optimal blend compositions are achieved by the use of differentially pumped slot die...

  3. Stabilization of molten salt materials using metal chlorides for solar thermal storage.

    Science.gov (United States)

    Dunlop, T O; Jarvis, D J; Voice, W E; Sullivan, J H

    2018-05-29

    The effect of a variety of metal-chlorides additions on the melting behavior and thermal stability of commercially available salts was investigated. Ternary salts comprised of KNO 3, NaNO 2, and NaNO 3 were produced with additions of a variety of chlorides (KCl, LiCl, CaCl 2 , ZnCl 2 , NaCl and MgCl 2 ). Thermogravimetric analysis and weight loss experiments showed that the quaternary salt containing a 5 wt% addition of LiCl and KCl led to an increase in short term thermal stability compared to the ternary control salts. These additions allowed the salts to remain stable up to a temperature of 630 °C. Long term weight loss experiments showed an upper stability increase of 50 °C. A 5 wt% LiCl addition resulted in a weight loss of only 25% after 30 hours in comparison to a 61% loss for control ternary salts. Calorimetry showed that LiCl additions allow partial melting at 80 °C, in comparison to the 142 °C of ternary salts. This drop in melting point, combined with increased stability, provided a molten working range increase of almost 100 °C in total, in comparison to the control ternary salts. XRD analysis showed the oxidation effect of decomposing salts and the additional phase created with LiCl additions to allow melting point changes to occur.

  4. Evaluation of an economical sunlamp that emits a near solar UV power spectrum for conducting photoimmunological and sunscreen immune protection studies

    International Nuclear Information System (INIS)

    Beasley, D.G.; Roberts, L.K.; Beard, J.; Stanfield, J.W.

    1996-01-01

    Unlike FS-type UVB sunlamps, which have a significant amount of effective immunosuppressive non-solar UV energy at wavelengths below 295 nm, the immunosuppression effectiveness spectrum of UVA-340 sunlamps was nearly identical to that of a solar simulator. The purpose of this study was to evaluate this sunlamp for conducting photoimmunological and sunscreen immune protection studies. Groups of C3H mice were exposed to a range of UVA-340 sunlamp doses (0.25 kJ/m 2 to 20.0 kJ/m 2 ) to establish a dose-response curve and determine the minimum immune suppression dose (MISD) for induction of local-type suppression of contact hypersensitivity (CH). The MISD, defined as the lowest UV dose given to produce ∼ 50% suppression of the CH response in mice, was determined to be 1.0 kJ/m 2 for UVA-340 sunlamps. Immune protection tests on four marketed sunscreen lotions (sun protection factors [SPF] 4, 8, 15 and 30) were then conducted with UVA-340 sunlamps using MISD as the endpoint. The immune protection factors for these sunscreens were equivalent to the level of protection predicted by their labeled SPF. These results are similar to those we have previously obtained using a solar simulator. (author)

  5. A comparative study of fluorine substituents for enhanced stability of flexible and ITO-free high-performance polymer solar cells

    DEFF Research Database (Denmark)

    Carlé, Jon Eggert; Helgesen, Martin; Zawacka, Natalia Klaudia

    2014-01-01

    lifetime in flexible large area roll-coated bulk heterojunction solar cells. The two polymer series have different side chains on the BDT unit, namely 2-hexyldecyloxy (BDTHDO) (P1-P3) or 2-hexyldecylthiophene (BDT THD) (P4-P6). The photochemical stability clearly shows that the stability enhances along...... with the number of fluorine atoms incorporated on the polymer backbone. Fabrication of the polymer solar cells based on the materials was carried out in ambient atmosphere on a roll coating/printing machine employing flexible and indium-tin-oxide-free plastic substrates. Solar cells based on the P4-P6 series...... in the performance followed by a much slower decay rate, still retaining 40-55% of their initial performance after 250 h of testing under ISOS-L-1 conditions. © 2014 Wiley Periodicals, Inc....

  6. Solution processed transition metal oxide anode buffer layers for efficiency and stability enhancement of polymer solar cells

    Science.gov (United States)

    Ameen, M. Yoosuf; Shamjid, P.; Abhijith, T.; Reddy, V. S.

    2018-01-01

    Polymer solar cells were fabricated with solution-processed transition metal oxides, MoO3 and V2O5 as anode buffer layers (ABLs). The optimized device with V2O5 ABL exhibited considerably higher power conversion efficiency (PCE) compared to the devices based on MoO3 and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) ABLs. The space charge limited current measurements and impedance spectroscopy results of hole-only devices revealed that V2O5 provided a very low charge transfer resistance and high hole mobility, facilitating efficient hole transfer from the active layer to the ITO anode. More importantly, incorporation of V2O5 as ABL resulted in substantial improvement in device stability compared to MoO3 and PEDOT:PSS based devices. Unencapsulated PEDOT:PSS-based devices stored at a relative humidity of 45% have shown complete failure within 96 h. Whereas, MoO3 and V2O5 based devices stored in similar conditions retained 22% and 80% of their initial PCEs after 96 h. Significantly higher stability of the V2O5-based device is ascribed to the reduction in degradation of the anode/active layer interface, as evident from the electrical measurements.

  7. Stability of CIGS Solar Cells and Component Materials Evaluated by a Step-Stress Accelerated Degradation Test Method: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Pern, F. J.; Noufi, R.

    2012-10-01

    A step-stress accelerated degradation testing (SSADT) method was employed for the first time to evaluate the stability of CuInGaSe2 (CIGS) solar cells and device component materials in four Al-framed test structures encapsulated with an edge sealant and three kinds of backsheet or moisture barrier film for moisture ingress control. The SSADT exposure used a 15oC and then a 15% relative humidity (RH) increment step, beginning from 40oC/40%RH (T/RH = 40/40) to 85oC/70%RH (85/70) as of the moment. The voluminous data acquired and processed as of total DH = 3956 h with 85/70 = 704 h produced the following results. The best CIGS solar cells in sample Set-1 with a moisture-permeable TPT backsheet showed essentially identical I-V degradation trend regardless of the Al-doped ZnO (AZO) layer thickness ranging from standard 0.12 μm to 0.50 μm on the cells. No clear 'stepwise' feature in the I-V parameter degradation curves corresponding to the SSADT T/RH/time profile was observed. Irregularity in I-V performance degradation pattern was observed with some cells showing early degradation at low T/RH < 55/55 and some showing large Voc, FF, and efficiency degradation due to increased series Rs (ohm-cm2) at T/RH ≥ 70/70. Results of (electrochemical) impedance spectroscopy (ECIS) analysis indicate degradation of the CIGS solar cells corresponded to increased series resistance Rs (ohm) and degraded parallel (minority carrier diffusion/recombination) resistance Rp, capacitance C, overall time constant Rp*C, and 'capacitor quality' factor (CPE-P), which were related to the cells? p-n junction properties. Heating at 85/70 appeared to benefit the CIGS solar cells as indicated by the largely recovered CPE-P factor. Device component materials, Mo on soda lime glass (Mo/SLG), bilayer ZnO (BZO), AlNi grid contact, and CdS/CIGS/Mo/SLG in test structures with TPT showed notable to significant degradation at T/RH ≥ 70/70. At T/RH = 85/70, substantial blistering of

  8. Structurally stabilized mesoporous TiO2 nanofibres for efficient dye-sensitized solar cells

    Directory of Open Access Journals (Sweden)

    Fargol Hasani Bijarbooneh

    2013-09-01

    Full Text Available One-dimensional (1D TiO2 nanostructures are very desirable for providing fascinating properties and features, such as high electron mobility, quantum confinement effects, and high specific surface area. Herein, 1D mesoporous TiO2 nanofibres were prepared using the electrospinning method to verify their potential for use as the photoelectrode of dye-sensitized solar cells (DSSCs. The 1D mesoporous nanofibres, 300 nm in diameter and 10-20 μm in length, were aggregated from anatase nanoparticles 20-30 nm in size. The employment of these novel 1D mesoporous nanofibres significantly improved dye loading and light scattering of the DSSC photoanode, and resulted in conversion cell efficiency of 8.14%, corresponding to an ∼35% enhancement over the Degussa P25 reference photoanode.

  9. Solid polymeric electrolyte based dye-sensitized solar cell with improved stability

    Science.gov (United States)

    Prasad, Narottam; Kumar, Manish; Patel, K. R.; Roy, M. S.

    2018-05-01

    The impact of polymeric electrolyte was investigated over the performance of dye-sensitized solar cell made with Rose Bengal as sensitizer. Further, the selective influence of TiCl4 treatment and pre-sensitizer deoxycholic acid on nc-TiO2 photoanode was determined in terms of improvement in conversion efficiency of the cell. It is found that the effect of TiCl4 treatment was comparatively more than pre-sensitization with de-oxy cholic acid towards improving the efficiency of the cell. The conversion efficiency on TiCl4 treatment was 0.2% whereas on pre-sensitization with deoxy chollic acid it was 0.1%. The combined effect of both TiCl4 treatment & pre-sensitization with deoxycholic acid leads conversion efficiency to 0.33%.

  10. Structure, longitudinal invariance, and stability of the Child Behavior Checklist 1½-5's Diagnostic and Statistical Manual of Mental Disorders-Autism Spectrum Disorder scale: Findings from Generation R (Rotterdam).

    Science.gov (United States)

    Rescorla, Leslie A; Ghassabian, Akhgar; Ivanova, Masha Y; Jaddoe, Vincent Wv; Verhulst, Frank C; Tiemeier, Henning

    2017-11-01

    Although the Child Behavior Checklist 1½-5's 12-item Diagnostic and Statistical Manual of Mental Disorders-Autism Spectrum Problems Scale (formerly called Pervasive Developmental Problems scale) has been used in several studies as an autism spectrum disorder screener, the base rate and stability of its items and its measurement model have not been previously studied. We therefore examined the structure, longitudinal invariance, and stability of the Child Behavior Checklist 1½-5's Diagnostic and Statistical Manual of Mental Disorders-Autism Spectrum Problems Scale in the diverse Generation R (Rotterdam) sample based on mothers' ratings at 18 months ( n = 4695), 3 years ( n = 4571), and 5 years ( n = 5752). Five items that seemed especially characteristic of autism spectrum disorder had low base rates at all three ages. The rank order of base rates for the 12 items was highly correlated over time ( Qs ⩾ 0.86), but the longitudinal stability of individual items was modest (phi coefficients = 0.15-0.34). Confirmatory factor analyses indicated that the autism spectrum disorder scale model manifested configural, metric, and scalar longitudinal invariance over the time period from 18 months to 5 years, with large factor loadings. Correlations over time for observed autism spectrum disorder scale scores (0.25-0.50) were generally lower than the correlations across time of the latent factors (0.45-0.68). Results indicated significant associations of the autism spectrum disorder scale with later autism spectrum disorder diagnoses.

  11. Theoretical study on thermal stability of molten salt for solar thermal power

    International Nuclear Information System (INIS)

    Wei, Xiaolan; Peng, Qiang; Ding, Jing; Yang, Xiaoxi; Yang, Jianping; Long, Bin

    2013-01-01

    Molten salt (HTS) composed of 53% KNO 3 , 40% NaNO 2 and 7 wt.% NaNO 3 has been used as heat transfer media and thermal storage fluid in the solar thermal power, but thermal decomposition will occur at higher temperature because of the oxidation of nitrite to nitrate in the air. In this paper, the reaction mechanism of NO 2 − oxidation is researched by quantum mechanical method. The results show that two components of the transition state (O 2 NO 2 − ) and intermediate ([NO 4 − ]) are found in the reaction. This reaction is an exothermic reaction and the activation barrier is 94.0 kJ mol −1 . The energy difference of this reaction is very large, so the reaction rate is very slow. -- Highlights: ► The mechanism of the oxidation of nitrite salt in HTS is explained. ► Two components of the transition state (O 2 NO 2 − ) and intermediate ([NO 4 − ]) are found. ► The activation barrier of the nitrite oxidation is determined

  12. Stability and Performance of CsPbI2Br Thin Films and Solar Cell Devices.

    Science.gov (United States)

    Mariotti, Silvia; Hutter, Oliver S; Phillips, Laurie J; Yates, Peter J; Kundu, Biswajit; Durose, Ken

    2018-01-31

    In this manuscript, the inorganic perovskite CsPbI 2 Br is investigated as a photovoltaic material that offers higher stability than the organic-inorganic hybrid perovskite materials. It is demonstrated that CsPbI 2 Br does not irreversibly degrade to its component salts as in the case of methylammonium lead iodide but instead is induced (by water vapor) to transform from its metastable brown cubic (1.92 eV band gap) phase to a yellow phase having a higher band gap (2.85 eV). This is easily reversed by heating to 350 °C in a dry environment. Similarly, exposure of unencapsulated photovoltaic devices to water vapor causes current (J SC ) loss as the absorber transforms to its more transparent (yellow) form, but this is also reversible by moderate heating, with over 100% recovery of the original device performance. NMR and thermal analysis show that the high band gap yellow phase does not contain detectable levels of water, implying that water induces the transformation but is not incorporated as a major component. Performances of devices with best efficiencies of 9.08% (V OC = 1.05 V, J SC = 12.7 mA cm -2 and FF = 68.4%) using a device structure comprising glass/ITO/c-TiO 2 /CsPbI 2 Br/Spiro-OMeTAD/Au are presented, and further results demonstrating the dependence of the performance on the preparation temperature of the solution processed CsPbI 2 Br films are shown. We conclude that encapsulation of CsPbI 2 Br to exclude water vapor should be sufficient to stabilize the cubic brown phase, making the material of interest for use in practical PV devices.

  13. Quantum dot solar cell

    International Nuclear Information System (INIS)

    Ahamefula, U.C.; Sulaiman, M.Y.; Sopian, K.; Ibarahim, Z.; Ibrahim, N.; Alghoul, M.A.; Haw, L.C.; Yahya, M.; Amin, N.; Mat, S.; Ruslan, M.H.

    2009-01-01

    Full text: The much awaited desire of replacing fossil fuel with photovoltaic will remain a fairy tale if the myriad of issues facing solar cell development are marginalized. Foremost in the list is the issue of cost. Silicon has reached a stage where its use on large scale can no longer be lavishly depended upon. The demand for high grade silicon from the microelectronics and solar industries has soared leading to scarcity. New approach has to be sought. Notable is the increased attention on thin films such as cadmium telluride, copper indium gallium diselenide, amorphous silicon, and the not so thin non-crystalline family of silicon. While efforts to address the issues of stability, toxicity and efficiency of these systems are ongoing, another novel approach is quietly making its appearance - quantum dots. Quantum dots seem to be promising candidates for solar cells because of the opportunity to manipulate their energy levels allowing absorption of a wider solar spectrum. Utilization of minute quantity of these nano structures is enough to bring the cost of solar cell down and to ascertain sustainable supply of useful material. The paper outlines the progress that has been made on quantum dot solar cells. (author)

  14. Effect of current sheets on the solar wind magnetic field power spectrum from the Ulysses observation: from Kraichnan to Kolmogorov scaling.

    Science.gov (United States)

    Li, G; Miao, B; Hu, Q; Qin, G

    2011-03-25

    The MHD turbulence theory developed by Iroshnikov and Kraichnan predicts a k(-1.5) power spectrum. Solar wind observations, however, often show a k(-5/3) Kolmogorov scaling. Based on 3 years worth of Ulysses magnetic field data where over 28,000 current sheets are identified, we propose that the current sheet is the cause of the Kolmogorov scaling. We show that for 5 longest current-sheet-free periods the magnetic field power spectra are all described by the Iroshnikov-Kraichnan scaling. In comparison, for 5 periods that have the most number of current sheets, the power spectra all exhibit Kolmogorov scaling. The implication of our results is discussed.

  15. Measurement of macroscopic plasma parameters with a radio experiment: Interpretation of the quasi-thermal noise spectrum observed in the solar wind

    Science.gov (United States)

    Couturier, P.; Hoang, S.; Meyer-Vernet, N.; Steinberg, J. L.

    1983-01-01

    The ISEE-3 SBH radio receiver has provided the first systematic observations of the quasi-thermal (plasma waves) noise in the solar wind plasma. The theoretical interpretation of that noise involves the particle distribution function so that electric noise measurements with long antennas provide a fast and independent method of measuring plasma parameters: densities and temperatures of a two component (core and halo) electron distribution function have been obtained in that way. The polarization of that noise is frequency dependent and sensitive to the drift velocity of the electron population. Below the plasma frequency, there is evidence of a weak noise spectrum with spectral index -1 which is not yet accounted for by the theory. The theoretical treatment of the noise associated with the low energy (thermal) proton population shows that the moving electrical antenna radiates in the surrounding plasma by Carenkov emission which becomes predominant at the low frequencies, below about 0.1 F sub P.

  16. Mg IX emission lines in an active region spectrum obtained with the Solar EUV Rocket Telescope and Spectrograph (SERTS)

    Science.gov (United States)

    Keenan, F. P.; Thomas, R. J.; Neupert, W. M.; Conlon, E. S.

    1994-01-01

    Theoretical electron-temperature-sensitive Mg IX emission line ratios are presented for R(sub 1) = I(443.96 A)/I(368.06 A), R(sub 2) = I(439.17 A)/I(368.06 A), R(sub 3) = I(443.37 A)/I(368.06 A), R(sub 4) = I(441.22 A)/I(368.06 A), and R(sub 5) = I(448.28 A)/I(368.06 A). A comparison of these with observational data for a solar active region, obtained during a rocket flight by the Solar EUV Rocket Telescope and Spectrograph (SERTS), reveals excellent agreement between theory and observation for R(sub 1) through R(sub 4), with discrepancies that average only 9%. This provides experimental support for the accuracy of the atomic data adopted in the line ratio calculations, and also resolves discrepancies found previously when the theoretical results were compared with solar data from the S082A instrument on board Skylab. However in the case of R(sub 5), the theoretical and observed ratios differ by almost a factor of 2. This may be due to the measured intensity of the 448.28 A line being seriously affected by instrumental effects, as it lies very close to the long wavelength edge of the SERTS spectral coverage (235.46-448.76 A).

  17. Stability and sealing of PEC solar cells; Stabilitet og forsegling af PEC solceller

    Energy Technology Data Exchange (ETDEWEB)

    Lauritzen, H.

    2009-06-15

    A requirement for success of the DSC technology on the market for building-integrated PV is visually attractive DSC panels holding a lifetime comparable to alternative facade materials and delivering electricity at reasonable prices. This project concerns the stability and durability of the DSC panel as these are decisive factors for the lifetime of the panels and the price of the produced electricity. The largest challenge of the DSC sealing is the high-performing well-documented - but also aggressive and volatile - iodine/triiodide electrolyte. The heat-sensitive Ru-dyes represent another challenge, as the dye should not be exposed to temperatures above approx. 100 deg. C during the sealing process. Despite the fact that less aggressive electrolytes and more stable dyes are highly focused R and D tasks, the work in the actual project has been carried out according to a 'worst case' strategy, i.e. the search has been for a sealing which is compatible with the iodine/triiodide electrolyte and the Ru-dyes. The rationale behind this strategy is the demanding lifetime requirement s for building-integrated products, which requires the ultimate sealing. In addition to the focus on the DSC sealing, work has been dedicated to the development of a more encapsulation-friendly electrolyte, in which the electrolyte's volatile component has been replaced by an ionic liquid. The ultimate result of the project is an improved polymer edge sealing for DSC cells. The sealant is - contrary to Surlyn and Bynel - stable in contact with the aggressive iodine/ triiodide electrolyte. The sealing is formed by lamination at elevated temperature and under controlled conditions. The robustness and capacity of the sealing process need to be further improved in order to fulfill the laboratories ambitions with regard to volume production of DSC cells and modules. Furthermore should the new sealing be compared both stability-wise and cost-wise with the lead-free solder glass

  18. Photo-stability study of a solution-processed small molecule solar cell system: correlation between molecular conformation and degradation.

    Science.gov (United States)

    Newman, Michael J; Speller, Emily M; Barbé, Jérémy; Luke, Joel; Li, Meng; Li, Zhe; Wang, Zhao-Kui; Jain, Sagar M; Kim, Ji-Seon; Lee, Harrison Ka Hin; Tsoi, Wing Chung

    2018-01-01

    Solution-processed organic small molecule solar cells (SMSCs) have achieved efficiency over 11%. However, very few studies have focused on their stability under illumination and the origin of the degradation during the so-called burn-in period. Here, we studied the burn-in period of a solution-processed SMSC using benzodithiophene terthiophene rhodamine:[6,6]-phenyl C 71 butyric acid methyl ester (BTR:PC 71 BM) with increasing solvent vapour annealing time applied to the active layer, controlling the crystallisation of the BTR phase. We find that the burn-in behaviour is strongly correlated to the crystallinity of BTR. To look at the possible degradation mechanisms, we studied the fresh and photo-aged blend films with grazing incidence X-ray diffraction, UV-vis absorbance, Raman spectroscopy and photoluminescence (PL) spectroscopy. Although the crystallinity of BTR affects the performance drop during the burn-in period, the degradation is found not to originate from the crystallinity changes of the BTR phase, but correlates with changes in molecular conformation - rotation of the thiophene side chains, as resolved by Raman spectroscopy which could be correlated to slight photobleaching and changes in PL spectra.

  19. Stabilized efficiency of stacked a-Si solar cell; Sekisogata a-Si taiyo denchi no anteika koritsu

    Energy Technology Data Exchange (ETDEWEB)

    Takahisa, K; Kojima, T; Nakamura, K; Koyanagi, T; Yanagisawa, T [Electrotechnical Laboratory, Tsukuba (Japan)

    1997-11-25

    Different types of tests combining light and temperature were carried out in a laboratory on predicting long-term performance of stacked amorphous silicon solar cells. Cell terminals were left open, xenon was used as an irradiation light source, and cell temperature was controlled within {+-} 2 degC of the setting. The result of the experiment may be summarized as follows: with regard to the deterioration characteristics, the speed in which the efficiency changes reached a maximum within 10 hours, and thereafter the change has slowed down gradually in the case of temperature at 50 degC; in the case of 25 degC, the maximization is reached between 500 and 1000 hours; the stabilization efficiency turns out to be a pessimistic value according to the saturated value derived from an experimental expression, hence the value would have to be expressed by specifying cell temperatures, light intensities and elapsed time; the minimum value of seasonal variation may be estimated at about 85% as a pessimistic value; for recovery characteristics, the saturated value for the recovery tends to become lower as the lower the value immediately before the recovery; and if the light intensity is varied, the deterioration characteristic shifts to that at an individual light intensity. 4 refs., 11 figs., 2 tabs.

  20. Carbon-Based CsPbBr3 Perovskite Solar Cells: All-Ambient Processes and High Thermal Stability.

    Science.gov (United States)

    Chang, Xiaowen; Li, Weiping; Zhu, Liqun; Liu, Huicong; Geng, Huifang; Xiang, Sisi; Liu, Jiaming; Chen, Haining

    2016-12-14

    The device instability has been an important issue for hybrid organic-inorganic halide perovskite solar cells (PSCs). This work intends to address this issue by exploiting inorganic perovskite (CsPbBr 3 ) as light absorber, accompanied by replacing organic hole transport materials (HTM) and the metal electrode with a carbon electrode. All the fabrication processes (including those for CsPbBr 3 and the carbon electrode) in the PSCs are conducted in ambient atmosphere. Through a systematical optimization on the fabrication processes of CsPbBr 3 film, carbon-based PSCs (C-PSCs) obtained the highest power conversion efficiency (PCE) of about 5.0%, a relatively high value for inorganic perovskite-based PSCs. More importantly, after storage for 250 h at 80 °C, only 11.7% loss in PCE is observed for CsPbBr 3 C-PSCs, significantly lower than that for popular CH 3 NH 3 PbI 3 C-PSCs (59.0%) and other reported PSCs, which indicated a promising thermal stability of CsPbBr 3 C-PSCs.

  1. The sun protection factor (SPF) inadequately defines broad spectrum photoprotection: demonstration using skin reconstructed in vitro exposed to UVA, UVBor UV-solar simulated radiation.

    Science.gov (United States)

    Bernerd, Françoise; Vioux, Corinne; Lejeune, François; Asselineau, Daniel

    2003-01-01

    Wavelength specific biological damage has been previously identified in human skin reconstructed in vitro. Sunburn cell and pyrimidine dimers were found after UVB exposure, and alterations of dermal fibroblasts after UVA exposure. These damages permitted us to discriminate UVB and UVA single absorbers. The present study shows that these biological effects can be obtained simultaneously by a combined UVB + UVA exposure using ultraviolet solar simulated light (UV-SSR), which represents a relevant UV source. In addition, the protection afforded by two broad spectrum sunscreen complex formulations was assessed after topical application. These two formulations displayed the same sun protection factor but different UVA protection factors determined by the persistent pigment darkening (PPD) method. Dose response experiments of UVA or UV-SSR showed that the preparation with the highest PF-UVA provided a better protection with regard to dermal damage compared to the other formulation. Using an original UVB source to obtain the UVB portion of SSR spectrum, the preparations provided the same protection. This study strikingly illustrates the fact that the photoprotection afforded by two sunscreen formulations having similar SPF values is not equal with regard to dermal damage related to photoaging.

  2. Stability enhancement of P3HT:PCBM polymer solar cells using thermally evaporated MoO3 anode buffer layer

    Science.gov (United States)

    Ameen, M. Yoosuf; Shamjid, P.; Abhijith, T.; Radhakrishnan, Thulasi; Reddy, V. S.

    2018-02-01

    Polymer solar cells have been fabricated with thermally evaporated MoO3 as anode buffer layer (ABL). The stability of MoO3 and PEDOT:PSS based devices was examined under different test conditions. The MoO3 based device exhibited a slightly better efficiency and significantly higher stability compared to PEDOT:PSS based device. At a relative humidity of 45% the unencapsulated PEDOT:PSS based device degraded completely within 96 h. On the other hand, MoO3 based device retained more than 60% of its initial efficiency after 96 h. The reason behind stability enhancement was investigated by measuring time-evolution of reflectance and hole-current. Experimental results revealed that the stability enhancement for MoO3 based device originates from the reduction in degradation of anode/active layer interface.

  3. Flexible ITO-free organic solar cells applying aqueous solution-processed V2O5 hole transport layer: An outdoor stability study

    Directory of Open Access Journals (Sweden)

    F. Anderson S. Lima

    2016-02-01

    Full Text Available Solution processable semiconductor oxides have opened a new paradigm for the enhancement of the lifetime of thin film solar cells. Their fabrication by low-cost and environmentally friendly solution-processable methods makes them ideal barrier (hole and electron transport layers. In this work, we fabricate flexible ITO-free organic solar cells (OPV by printing methods applying an aqueous solution-processed V2O5 as the hole transport layer (HTL and compared them to devices applying PEDOT:PSS. The transparent conducting electrode was PET/Ag/PEDOT/ZnO, and the OPV configuration was PET/Ag/PEDOT/ZnO/P3HT:PC60BM/HTL/Ag. Outdoor stability analyses carried out for more than 900 h revealed higher stability for devices fabricated with the aqueous solution-processed V2O5.

  4. Triple-junction thin-film silicon solar cell fabricated on periodically textured substrate with a stabilized efficiency of 13.6%

    Science.gov (United States)

    Sai, Hitoshi; Matsui, Takuya; Koida, Takashi; Matsubara, Koji; Kondo, Michio; Sugiyama, Shuichiro; Katayama, Hirotaka; Takeuchi, Yoshiaki; Yoshida, Isao

    2015-05-01

    We report a high-efficiency triple-junction thin-film silicon solar cell fabricated with the so-called substrate configuration. It was verified whether the design criteria for developing single-junction microcrystalline silicon (μc-Si:H) solar cells are applicable to multijunction solar cells. Furthermore, a notably high short-circuit current density of 32.9 mA/cm2 was achieved in a single-junction μc-Si:H cell fabricated on a periodically textured substrate with a high-mobility front transparent contacting layer. These technologies were also combined into a-Si:H/μc-Si:H/μc-Si:H triple-junction cells, and a world record stabilized efficiency of 13.6% was achieved.

  5. Heterostructured TiO2/NiTiO3 Nanorod Arrays for Inorganic Sensitized Solar Cells with Significantly Enhanced Photovoltaic Performance and Stability.

    Science.gov (United States)

    Li, Yue-Ying; Wang, Jian-Gan; Sun, Huan-Huan; Wei, Bingqing

    2018-04-11

    Organic dyes used in the conventional dye-sensitized solar cells (DSSCs) suffer from poor light stability and high cost. In this work, we demonstrate a new inorganic sensitized solar cell based on ordered one-dimensional semiconductor nanorod arrays of TiO 2 /NiTiO 3 (NTO) heterostructures prepared via a facile two-step hydrothermal approach. The semiconductor heterostructure arrays are highly desirable and promising for DSSCs because of their direct charge transport capability and slow charge recombination rate. The low-cost NTO inorganic semiconductor possesses an appropriate band gap that matches well with TiO 2 , which behaves like a "dye" to enable efficient light harvesting and fast electron-hole separation. The solar cells constructed by the ordered TiO 2 /NTO heterostructure photoanodes show a significantly improved power conversion efficiency, high fill factor, and more promising, outstanding life stability. The present work will open up an avenue to design heterostructured inorganics for high-performance solar cells.

  6. Spectral Kernel Approach to Study Radiative Response of Climate Variables and Interannual Variability of Reflected Solar Spectrum

    Science.gov (United States)

    Jin, Zhonghai; Wielicki, Bruce A.; Loukachine, Constantin; Charlock, Thomas P.; Young, David; Noeel, Stefan

    2011-01-01

    The radiative kernel approach provides a simple way to separate the radiative response to different climate parameters and to decompose the feedback into radiative and climate response components. Using CERES/MODIS/Geostationary data, we calculated and analyzed the solar spectral reflectance kernels for various climate parameters on zonal, regional, and global spatial scales. The kernel linearity is tested. Errors in the kernel due to nonlinearity can vary strongly depending on climate parameter, wavelength, surface, and solar elevation; they are large in some absorption bands for some parameters but are negligible in most conditions. The spectral kernels are used to calculate the radiative responses to different climate parameter changes in different latitudes. The results show that the radiative response in high latitudes is sensitive to the coverage of snow and sea ice. The radiative response in low latitudes is contributed mainly by cloud property changes, especially cloud fraction and optical depth. The large cloud height effect is confined to absorption bands, while the cloud particle size effect is found mainly in the near infrared. The kernel approach, which is based on calculations using CERES retrievals, is then tested by direct comparison with spectral measurements from Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) (a different instrument on a different spacecraft). The monthly mean interannual variability of spectral reflectance based on the kernel technique is consistent with satellite observations over the ocean, but not over land, where both model and data have large uncertainty. RMS errors in kernel ]derived monthly global mean reflectance over the ocean compared to observations are about 0.001, and the sampling error is likely a major component.

  7. A Simple Power Management Scheme with Enhanced Stability for a Solar PV/Wind/Fuel Cell/Grid Fed Hybrid Power Supply Designed for Industrial Loads

    Directory of Open Access Journals (Sweden)

    S. Saravanan

    2014-01-01

    Full Text Available This paper proposes a new power conditioner topology with an intelligent power management controller that integrates multiple renewable energy sources such as solar energy, wind energy, and fuel cell energy with battery and AC grid supply as backup to make the best use of their operating characteristics with better reliability than that could be obtained by single renewable energy source based power supply. The proposed embedded controller is programmed to perform MPPT for solar PV panel and WTG, SOC estimation and battery, maintaining a constant voltage at PCC and power flow control by regulating the reference currents of the controller in an instantaneous basis. The instantaneous variation in reference currents of the controller enhances the controller response as it accommodates the effect of continuously varying solar insolation and wind speed in the power management. It also prioritizes the sources for consumption to achieve maximum usage of green energy than grid energy. The simulation results of the proposed power management system with real-time solar radiation and wind velocity data collected from solar centre, KEC, and experimental results for a sporadically varying load demand are presented in this paper and the results are encouraging from reliability and stability perspectives.

  8. Early solar physics

    CERN Document Server

    Meadows, A J

    1970-01-01

    Early Solar Physics reviews developments in solar physics, particularly the advent of solar spectroscopy and the discovery of relationships between the various layers of the solar atmosphere and between the different forms of solar activity. Topics covered include solar observations during 1843; chemical analysis of the solar atmosphere; the spectrum of a solar prominence; and the solar eclipse of December 12, 1871. Spectroscopic observations of the sun are also presented. This book is comprised of 30 chapters and begins with an overview of ideas about the sun in the mid-nineteenth century, fo

  9. Poly(4-Vinylpyridine)-Based Interfacial Passivation to Enhance Voltage and Moisture Stability of Lead Halide Perovskite Solar Cells.

    Science.gov (United States)

    Chaudhary, Bhumika; Kulkarni, Ashish; Jena, Ajay Kumar; Ikegami, Masashi; Udagawa, Yosuke; Kunugita, Hideyuki; Ema, Kazuhiro; Miyasaka, Tsutomu

    2017-06-09

    It is well known that the surface trap states and electronic disorders in the solution-processed CH 3 NH 3 PbI 3 perovskite film affect the solar cell performance significantly and moisture sensitivity of photoactive perovskite material limits its practical applications. Herein, we show the surface modification of a perovskite film with a solution-processable hydrophobic polymer (poly(4-vinylpyridine), PVP), which passivates the undercoordinated lead (Pb) atoms (on the surface of perovskite) by its pyridine Lewis base side chains and thereby eliminates surface-trap states and non-radiative recombination. Moreover, it acts as an electron barrier between the perovskite and hole-transport layer (HTL) to reduce interfacial charge recombination, which led to improvement in open-circuit voltage (V oc ) by 120 to 160 mV whereas the standard cell fabricated in same conditions showed V oc as low as 0.9 V owing to dominating interfacial recombination processes. Consequently, the power conversion efficiency (PCE) increased by 3 to 5 % in the polymer-modified devices (PCE=15 %) with V oc more than 1.05 V and hysteresis-less J-V curves. Advantageously, hydrophobicity of the polymer chain was found to protect the perovskite surface from moisture and improved stability of the non-encapsulated cells, which retained their device performance up to 30 days of exposure to open atmosphere (50 % humidity). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. The part of the solar spectrum with the highest influence on the formation of SOA in the continental boundary layer

    Directory of Open Access Journals (Sweden)

    M. Boy

    2002-01-01

    Full Text Available The relationship between nucleation events and spectral solar irradiance was analysed using two years of data collected at the Station for Measuring Forest Ecosystem-Atmosphere Relations (SMEAR II in Hyytiälä, Finland. We analysed the data in two different ways. In the first step we calculated ten nanometer average values from the irradiance measurements between 280 and 580 nm and explored if any special wavelengths groups showed higher values on event days compared to a spectral reference curve for all the days for 2 years or to reference curves for every month. The results indicated that short wavelength irradiance between 300 and 340 nm is higher on event days in winter (February and March compared to the monthly reference graph but quantitative much smaller than in spring or summer. By building the ratio between the average values of different event classes and the yearly reference graph we obtained peaks between 1.17 and 1.6 in the short wavelength range (300--340 nm. In the next step we included number concentrations of particles between 3 and 10 nm and calculated correlation coefficients between the different wavelengths groups and the particles. The results were quite similar to those obtained previously; the highest correlation coefficients were reached for the spectral irradiance groups 3--5 (300--330 nm with average values for the single event classes around 0.6 and a nearly linear decrease towards higher wavelengths groups by 30%. Both analyses indicate quite clearly that short wavelength irradiance between 300 and 330 or 340 nm is the most important solar spectral radiation for the formation of newly formed aerosols. In the end we introduce a photochemical mechanism as one possible pathway how short wavelength irradiance can influence the formation of SOA by calculating the production rate of excited oxygen. This mechanism shows in which way short wavelength irradiance can influence the formation of new particles even though the

  11. Organic, cross-linking, and shape-stabilized solar thermal energy storage materials: A reversible phase transition driven by broadband visible light

    International Nuclear Information System (INIS)

    Wang, Yunming; Tang, Bingtao; Zhang, Shufen

    2014-01-01

    Graphical abstract: Organic shape-stabilized solar thermal energy storage materials (OCSPCMs) with broadband harvesting for visible light were obtained by crosslinking and color matching, which provided a new platform for improving the efficiency of solar radiation utilization. - Highlights: • Novel phase change materials (OCSPCMs) were obtained by crosslinking and color matching. • The η of the OCSPCM was higher than 0.74 (visible light from 400 nm to 700 nm). • The phase change latent heats of the OCSPCMs were more than 120 J/g. • The OCSPCM has excellent form-stable effect during phase change process. - Abstract: Broadband visible sunlight usage and shape-stabilized effect were achieved using organic, cross-linking, and shape-stabilized phase-changed materials (OCSPCMs) with broadband visible light absorption, which were obtained by cross-linking reticulation and color matching (yellow, red, and blue) according to solar irradiation energy density. The obtained OCSPCMs exhibited excellent form-stable phase-change energy storage and broadband visible light-harvesting. Under broadband irradiation (from 400 nm to 700 nm), the light-to-heat conversion and the thermal energy storage efficiency (η > 0.74) of the OCSPCMs were significantly improved upon solar irradiation by color matching compared with those of OCSPCMs with single-band selective absorption of visible light (yellow, red, or blue). Differential scanning calorimetric results indicated that the phase change temperatures and latent heats of OCSPCMs ranged from 32.6 °C to 60.2 °C and from 120.1 J/g to 132.7 J/g, respectively. The novel materials show a reversible (more than 200 cycles) phase transition via ON/OFF switching of visible light irradiation

  12. Spatial Atmospheric Pressure Atomic Layer Deposition of Tin Oxide as an Impermeable Electron Extraction Layer for Perovskite Solar Cells with Enhanced Thermal Stability.

    Science.gov (United States)

    Hoffmann, Lukas; Brinkmann, Kai O; Malerczyk, Jessica; Rogalla, Detlef; Becker, Tim; Theirich, Detlef; Shutsko, Ivan; Görrn, Patrick; Riedl, Thomas

    2018-02-14

    Despite the notable success of hybrid halide perovskite-based solar cells, their long-term stability is still a key-issue. Aside from optimizing the photoactive perovskite, the cell design states a powerful lever to improve stability under various stress conditions. Dedicated electrically conductive diffusion barriers inside the cell stack, that counteract the ingress of moisture and prevent the migration of corrosive halogen species, can substantially improve ambient and thermal stability. Although atomic layer deposition (ALD) is excellently suited to prepare such functional layers, ALD suffers from the requirement of vacuum and only allows for a very limited throughput. Here, we demonstrate for the first time spatial ALD-grown SnO x at atmospheric pressure as impermeable electron extraction layers for perovskite solar cells. We achieve optical transmittance and electrical conductivity similar to those in SnO x grown by conventional vacuum-based ALD. A low deposition temperature of 80 °C and a high substrate speed of 2.4 m min -1 yield SnO x layers with a low water vapor transmission rate of ∼10 -4 gm -2 day -1 (at 60 °C/60% RH). Thereby, in perovskite solar cells, dense hybrid Al:ZnO/SnO x electron extraction layers are created that are the key for stable cell characteristics beyond 1000 h in ambient air and over 3000 h at 60 °C. Most notably, our work of introducing spatial ALD at atmospheric pressure paves the way to the future roll-to-roll manufacturing of stable perovskite solar cells.

  13. Solar Simulator

    Science.gov (United States)

    1981-01-01

    Oriel Corporation's simulators have a high pressure xenon lamp whose reflected light is processed by an optical system to produce a uniform solar beam. Because of many different types of applications, the simulators must be adjustable to replicate many different areas of the solar radiation spectrum. Simulators are laboratory tools for such purposes as testing and calibrating solar cells, or other solar energy systems, testing dyes, paints and pigments, pharmaceuticals and cosmetic preparations, plant and animal studies, food and agriculture studies and oceanographic research.

  14. Recent developments in luminescent solar concentrators

    Science.gov (United States)

    van Sark, W. G. J. H. M.

    2014-10-01

    High efficiency photovoltaic devices combine full solar spectrum absorption and effective generation and collection of charge carriers, while commercial success depends on cost effectiveness in manufacturing. Spectrum modification using down shifting has been demonstrated in luminescent solar concentrators (LSCs) since the 1970s, as a cheap alternative for standard c-Si technology. LSCs consist of a highly transparent plastic plate, in which luminescent species are dispersed, which absorb incident light and emit light at a red-shifted wavelength, with high quantum efficiency. Material issues have hampered efficiency improvements, in particular re-absorption of light emitted by luminescent species and stability of these species. In this contribution, approaches are reviewed on minimizing re-absorption, which should allow surpassing the 10% luminescent solar concentrator efficiency barrier.

  15. Assessment of stability of the response versus scan angle for the S-NPP VIIRS reflective solar bands using pseudo-invariant desert and Dome C sites

    Science.gov (United States)

    Wu, Aisheng; Xiong, Xiaoxiong J.; Cao, Changyong

    2017-09-01

    The Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP (National Polar-orbiting Partnership) satellite has been in operation for over five years. VIIRS has 22 bands with a spectral range from 0.4 μm to 2.2 μm for the reflective solar bands (RSB). The Earth view swath covers a distance of 3000 km over scan angles of +/- 56.0° off nadir. The on-board calibration of the RSB relies on a solar diffuser (SD) located at a fixed scan angle and a solar diffuser stability monitor (SDSM). The response versus scan angle (RVS) was characterized prelaunch in ambient conditions and is currently used to determine the on-orbit response for all scan angles relative to the SD scan angle. Since the RVS is vitally important to the quality of calibrated level 1B products, it is important to monitor its on-orbit stability, particularly at the short wavelengths (blue) where the most degradation occurs. In this study, the RVS stability is examined based on reflectance trends collected at various scan angles over the selected pseudo-invariant desert sites in Northern Africa and the Dome C snow site in Antarctica. These trends are corrected by the site dependent BRDF (bi-directional reflectance function) model to reduce seasonally related fluctuations. The BRDF corrected trends are examined so any systematic drifts in the scan angle direction would indicate a potential change in RVS. The results of this study provide useful information on VIIRS RVS on-orbit stability performance.

  16. Stability of templated and nanoparticles dye-sensitized solar cells: photovoltaic and electrochemical investigation of degradation mechanisms at the photoelectrode interface

    International Nuclear Information System (INIS)

    Dewalque, Jennifer; Nguyen, Ngoc Duy; Colson, Pierre; Krins, Natacha; Cloots, Rudi; Henrist, Catherine

    2014-01-01

    Graphical abstract: Highly porous templated TiO 2 films are promising alternative to nanoparticle layers for dye-sensitized solar cell applications. However, the increase of the electron transfer surface could promote detrimental side reactions and accelerate cell degradation upon ageing. Therefore, stability of templated cells under UV exposure, visible light soaking and thermal stress was studied in comparison to nanoparticle cells. -- Highlights: •Stability of templated and nanoparticle dye-sensitized solar cells is compared. •Templated cells are more sensitive to UV degradation than nanoparticle cells. •Templated cells are as stable as nanoparticle cells under light soaking. •Templated cells are more stable than nanoparticle cells under thermal stress. •Templated cells present better overall performances than nanoparticle cells. -- Abstract: A key issue in the commercialization of dye-sensitized solar cells is to maintain high efficiency and long lifetime. As reported in the literature, dye-sensitized solar cells are stable under visible light soaking but thermal stress and UV exposure lead to efficiency degradation. However, all the stability studies published so far have been performed on cells whose TiO 2 electrodes were prepared by tape casting or screen printing of nanoparticle pastes/inks. The present study concerns cells based on highly porous templated TiO 2 electrodes, whose larger surface area could enhance the negative effects of thermal stress, light soaking and UV exposure. The long-term stability of these cells is compared with a classical nanoparticle-based cell using current-voltage measurements (I-V curves) and electrochemical impedance spectroscopy. Due to their higher active interface, templated cells are more sensitive than nanoparticle cells to UV illumination, although this can be easily solved in both cases by the use of a UV filter. The templated cells are as stable as the nanoparticle cells under visible light soaking (UV

  17. Zr-doped TiO2 nanoparticles synthesized via a sol-gel route and their application in dye-sensitized solar cells for thermo-stabilization

    Science.gov (United States)

    Pasche, Anastasia; Grohe, Bernd; Mittler, Silvia; Charpentier, Paul A.

    2017-06-01

    Dye-sensitized solar cells (DSSCs) are regarded as one of the most promising solar cells amongst third-generation photovoltaic technologies, particularly due to their low cost, easy preparation, and minor environmental impact compared to earlier-generation devices. However, they have been challenged by thermal energy losses and low cell efficiencies. This work examined the incorporation of zirconium (Zr) into the crystal lattice of titania nanoparticles (nTiO2) for subsequent fabrication into the photo anode of the DSSCs. The results showed that Zr doping of nTiO2 inhibited the anatase-rutile phase transition. Higher calcination temperatures gave increased titania crystallinity, and stabilized the nTiO2 aggregate pore structure and specific surface area, consequently improving the DSSC device performance. A doping concentration of 5 mol % Zr into the nTiO2 demonstrated the best resistance against thermal degradation, achieving an optimized retention of specific surface area. Solar simulation confirmed the results, indicating better heat stability, although lowering the DSSC efficiencies.

  18. Enhanced photovoltaic performance and long-term stability of dye-sensitized solar cells by incorporating SiO{sub 2} nanoparticles in binary ionic liquid electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hsin-Fang; Wu, Jhih-Lin; Hsu, Po-Ya [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC (China); Tung, Yung-Liang [Energy and Environment Research Laboratories, Industrial Technology Research Institute, Hsinchu 30013, Taiwan, ROC (China); Ouyang, Fan-Yi [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC (China); Kai, Ji-Jung, E-mail: jjkai@ess.nthu.edu.tw [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC (China)

    2013-02-01

    Hydrophilic SiO{sub 2} nanoparticles in a binary ionic liquid (bi-IL) consisting of 1-propyl-3-methylimidazolium iodide (PMII) and 1-ethyl-3-methyl-imidazolium dicyanimide (EMIDCA) facilitated electron transfer and solidified the electrolyte for a dye-sensitized solar cell (DSC). We investigated the dependence of charge transport and photovoltaic performance on the composition of bi-IL electrolytes with varied ratio of SiO{sub 2} nanoparticles. The electrochemical impedance spectra revealed a decreased resistance to charge transfer at the Pt counter electrode (R{sub ct1}) when SiO{sub 2} (up to 2.0 wt.%) was added, improving the photovoltaic parameters. The DSC based on a TiO{sub 2} nanocrystalline film (thickness 14.2 μm) with a composite ionic gel electrolyte of EMIDCA/PMII bi-IL (33 vol.% of EMIDCA) incorporating SiO{sub 2} (2 wt.%) exhibited a power conversion efficiency of 5.28% under simulated solar illumination (AM 1.5 G, 100 mW cm{sup −} {sup 2}). The durability of DSC with a SiO{sub 2} solidified electrolyte was superior to that of a liquid one, exhibiting good stability at 60 °C in darkness during an accelerated test for 1000 h. - Highlights: ► SiO{sub 2} nanoparticles were introduced in a binary ionic liquid electrolyte. ► Effect of various ratios of SiO{sub 2} nanoparticles in gel electrolytes was studied. ► Mechanism of charge transfer with addition of SiO{sub 2} nanoparticles was discussed. ► An enhanced solar to electric energy conversion efficiency of 5.28% was achieved. ► Thermal stability of a quasi-solid state dye-sensitized solar cell was improved.

  19. The film thickness dependent thermal stability of Al{sub 2}O{sub 3}:Ag thin films as high-temperature solar selective absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Xiao Xiudi; Xu Gang, E-mail: xiudixiao@163.com; Xiong Bin; Chen Deming; Miao Lei [Chinese Academy of Sciences, Key Laboratory of Renewable Energy and Gas Hydrates, Guangzhou Institute of Energy Conversion (China)

    2012-03-15

    The monolayer Al{sub 2}O{sub 3}:Ag thin films were prepared by magnetron sputtering. The microstructure and optical properties of thin film after annealing at 700 Degree-Sign C in air were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and spectrophotometer. It revealed that the particle shape, size, and distribution across the film were greatly changed before and after annealing. The surface plasmon resonance absorption and thermal stability of the film were found to be strongly dependent on the film thickness, which was believed to be associated with the evolution process of particle diffusion, agglomeration, and evaporation during annealing at high temperature. When the film thickness was smaller than 90 nm, the film SPR absorption can be attenuated until extinct with increasing annealing time due to the evaporation of Ag particles. While the film thickness was larger than 120 nm, the absorption can keep constant even after annealing for 64 h due to the agglomeration of Ag particles. On the base of film thickness results, the multilayer Al{sub 2}O{sub 3}:Ag solar selective thin films were prepared and the thermal stability test illustrated that the solar selectivity of multilayer films with absorbing layer thickness larger than 120 nm did not degrade after annealing at 500 Degree-Sign C for 70 h in air. It can be concluded that film thickness is an important factor to control the thermal stability of Al{sub 2}O{sub 3}:Ag thin films as high-temperature solar selective absorbers.

  20. Effect of the Side Chains and Anode Material on Thermal Stability and Performance of Bulk-Heterojunction Solar Cells Using DPP(TBFu2 Derivatives as Donor Materials

    Directory of Open Access Journals (Sweden)

    Alexander Kovalenko

    2015-01-01

    Full Text Available An optimized fabrication of bulk-heterojunction solar cells (BHJ SCs based on previously reported diketopyrrolopyrrole donor, ethyl-hexylated DPP(TBFu2, as well as two new DPP(TBFu2 derivatives with ethyl-hexyl acetate and diethyl acetal solubilizing side-chains and PC60BM as an acceptor is demonstrated. Slow gradual annealing of the solar cell causing the effective donor-acceptor reorganization, and as a result higher power conversion efficiency (PCE, is described. By replacing a hole transporting layer PEDOT:PSS with MoO3 we obtained higher PCE values as well as higher thermal stability of the anode contact interface. DPP(TBFu2 derivative containing ethyl-hexyl acetate solubilizing side-chains possessed the best as-cast self-assembly and high crystallinity. However, the presence of ethyl-hexyl acetate and diethyl acetal electrophilic side-chains stabilizes HOMO energy of isolated DPP(TBFu2 donors with respect to the ethyl-hexylated one, according to cyclic voltammetry.

  1. Fast Crystallization and improved Stability of Perovskite Solar Cells with Zn 2 SnO 4 Electron Transporting Layer: Interface Matters

    KAUST Repository

    Bera, Ashok

    2015-12-03

    Here we report that mesoporous ternary oxide Zn2SnO4 can significantly promotes the crystallization of hybrid perovskite layers and serves as an efficient electron transporting material in perovskite solar cells. Such devices exhibit an energy conversion efficiency of 13.34%, which is even higher than that achieved with the commonly used TiO2 in the similar experimental conditions (9.1%). Simple one-step spin coating of CH3NH3PbI3−xClx on Zn2SnO4 is found to lead to rapidly crystalized bilayer perovskite structure without any solvent engineering. Furthermore, ultrafast transient absorption measurement reveals efficient charge transfer at the Zn2SnO4/perovskite interface. Most importantly, solar cells with Zn2SnO4 as the electron-transporting material exhibit negligible electrical hysteresis and exceptionally high stability without encapsulation for over one month. Besides underscoring Zn2SnO4 as a highly promising electron transporting material for perovskite solar cells, our results demonstrate the significant role of interfaces on improving the perovskite crystallization and photovoltaic performance.

  2. N-type polymers as electron extraction layers in hybrid perovskite solar cells with improved ambient stability

    NARCIS (Netherlands)

    Shao, S.; Chen, Z.; Fang, H. -H.; ten Brink, G. H.; Bartesaghi, D.; Adjokatse, S.; Koster, L. J. A.; Kooi, B. J.; Facchetti, A.; Loi, M. A.

    2016-01-01

    We studied three n-type polymers of the naphthalenediimide-bithiophene family as electron extraction layers (EELs) in hybrid perovskite solar cells. The recombination mechanism in these devices is found to be heavily influenced by the EEL transport properties. The maximum efficiency of the devices

  3. Solar Water Splitting Using Semiconductor Photocatalyst Powders

    KAUST Repository

    Takanabe, Kazuhiro

    2015-01-01

    Solar energy conversion is essential to address the gap between energy production and increasing demand. Large scale energy generation from solar energy can only be achieved through equally large scale collection of the solar spectrum. Overall water

  4. Study on the chemical stability of catalyst counter electrodes for dye-sensitized solar cells using a simple X-ray photoelectron spectroscopy-based method

    Science.gov (United States)

    Yun, Dong-Jin; Kim, Jungmin; Chung, Jongwon; Park, SungHoon; Baek, WoonJoong; Kim, Yongsu; Kim, Seongheon; Kwon, Young-Nam; Chung, JaeGwan; Kyoung, Yongkoo; Kim, Ki-Hong; Heo, Sung

    2014-12-01

    Since the chemical/electrical stability and catalytic activity are essential conditions for catalyst counter electrodes (CCEs) in dye-sensitized solar cells (DSSCs), a simple dipping method is employed for evaluating the chemical stability of CCE candidates in an iodine-based liquid electrolyte (I-electrolyte). The chemical stabilities and transition mechanisms of the CCEs are successfully analyzed by studying the chemical transitions in X-ray photoelectron spectroscopy (XPS) core levels after dipping in the I-electrolyte. All films including the Pt film undergo degradation depending on the type of material. While dipping in the I-electrolyte, Cu and Au films scarcely dissolves as their respective metal sulfides, and the Al film gradually loss its metallic properties owing to Al2O3 growth. On the other hand, a previously unknown transition mechanism of organic conducting CCEs is determined based on the proposed method. Compared to the other metal films, the poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) and multi wall carbon nanotube (MWCNT)/PEDOT:PSS films undergo an entirely unique transition mechanism, which results from the chemical adsorption of organic molecules onto PEDOT:PSS molecules in the I-electrolyte. Consequently, these chemical structure transitions correspond well to the degrees of alternation in the electrical properties of DSSCs with all the investigated CCEs.

  5. Photovoltaic performance and stability of fullerene/cerium oxide double electron transport layer superior to single one in p-i-n perovskite solar cells

    Science.gov (United States)

    Xing, Zhou; Li, Shu-Hui; Wu, Bao-Shan; Wang, Xin; Wang, Lu-Yao; Wang, Tan; Liu, Hao-Ran; Zhang, Mei-Lin; Yun, Da-Qin; Deng, Lin-Long; Xie, Su-Yuan; Huang, Rong-Bin; Zheng, Lan-Sun

    2018-06-01

    Interface engineering that involves in the metal cathodes and the electron transport layers (ETLs) facilitates the simultaneous improvement of device performances and stability in perovskite solar cells (PSCs). Herein, low-temperature solution-processed cerium oxide (CeOx) films are prepared by a facile sol-gel method and employed as the interface layers between [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) and an Ag back contact to form PC61BM/CeOx double ETLs. The introduction of CeOx enables electron extraction to the Ag electrode and protects the underlying perovskite layer and thus improves the device performance and stability of the p-i-n PSCs. The p-i-n PSCs with double PC61BM/CeOx ETLs demonstrate a maximum power conversion efficiency (PCE) of 17.35%, which is superior to those of the devices with either PC61BM or CeOx single ETLs. Moreover, PC61BM/CeOx devices exhibit excellent stability in light soaking, which is mainly due to the chemically stable CeOx interlayer. The results indicate that CeOx is a promising interface modification layer for stable high-efficiency PSCs.

  6. Revealing the influence of Cyano in Anchoring Groups of Organic Dyes on Adsorption Stability and Photovoltaic Properties for Dye-Sensitized Solar Cells.

    Science.gov (United States)

    Chen, Wei-Chieh; Nachimuthu, Santhanamoorthi; Jiang, Jyh-Chiang

    2017-07-10

    Determining an ideal adsorption configuration for a dye on the semiconductor surface is an important task in improving the overall efficiency of dye-sensitized solar cells. Here, we present a detailed investigation of different adsorption configurations of designed model dyes on TiO 2 anatase (101) surface using first principles methods. Particularly, we aimed to investigate the influence of cyano group in the anchoring part of dye on its adsorption stability and the overall photovoltaic properties such as open circuit voltage, electron injection ability to the surface. Our results indicate that the inclusion of cyano group increases the stability of adsorption only when it adsorbs via CN with the surface and it decreases the photovoltaic properties when it does not involve in binding. In addition, we also considered full dyes based on the results of model dyes and investigated the different strength of acceptor abilities on stability and electron injection ability. Among the various adsorption configurations considered here, the bidentate bridging mode (A3) is more appropriate one which has higher electron injection ability, larger V OC value and more importantly it has higher dye loading on the surface.

  7. A high-resolution atlas of the infrared spectrum of the Sun and the Earth atmosphere from space. Volume 3: Key to identification of solar features

    Science.gov (United States)

    Geller, Murray

    1992-01-01

    During the period April 29 through May 2, 1985, the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment was operated as part of the Spacelab-3 (SL-3) payload on the shuttle Challenger. The instrument, a Fourier transform spectrometer, recorded over 2000 infrared solar spectra from an altitude of 360 km. Although the majority of the spectra were taken through the limb of the Earth's atmosphere in order to better understand its composition, several hundred of the 'high-sun' spectra were completely free from telluric absorption. These high-sun spectra recorded from space are, at the present time, the only high-resolution infrared spectra ever taken of the Sun free from absorptions due to constituents in the Earth's atmosphere. Volumes 1 and 2 of this series provide a compilation of these spectra arranged in a format suitable for quick-look reference purposes and are the first record of the continuous high-resolution infrared spectrum of the Sun and the Earth's atmosphere from space. In the Table of Identifications, which constitutes the main body of this volume, each block of eight wavenumbers is given a separate heading and corresponds to a page of two panels in Volume 1 of this series. In addition, three separate blocks of data available from ATMOS from 622-630 cm(exp -1), 630-638 cm(exp -1) and 638-646 cm(exp -1), excluded from Volume 1 because of the low signal-to-noise ratio, have been included due to the certain identification of several OH and NH transitions. In the first column of the table, the corrected frequency is given. The second column identifies the molecular species. The third and fourth columns represent the assigned transition. The fifth column gives the depth of the molecular line in millimeters. Also included in this column is a notation to indicate whether the line is a blend or lies on the shoulder(s) of another line(s). The final column repeats a question mark if the line is unidentified.

  8. Polychromatic light (480-3400nm) similar to the terrestrial solar spectrum without its UV component in post-surgical immunorehabilitation of breast cancer patients.

    Science.gov (United States)

    Zhevago, Natalia A; Zimin, Alexander A; Glazanova, Tatyana V; Davydova, Natalia I; Bychkova, Natalia V; Chubukina, Zhanna V; Buinyakova, Anna I; Ballyuzek, Marina F; Samoilova, Kira A

    2017-01-01

    To this day, two methods of phototherapy (PT) have been successfully used in post-surgical immunorehabilitation of patients with breast cancer (BC): intravenous laser irradiation of the patients' blood and reinfusion of lympholeukosuspension of BC patients after single irradiation with HeNe laser. The objective of this pilot experimental study was to verify the effectiveness of the percutaneous use of polychromatic visible light combined with polychromatic infrared (pVIS+pIR) radiation similar to the major components of natural solar spectrum in post-surgical management of BC patients. Patients with BC (adenocarcinoma) of I-II stages, n=19 who had undergone mastectomy, were divided into 2 groups. The control group of patients (n=8) underwent a conventional course of post-surgical rehabilitation and sham irradiation. Patients of the PT group (n=11) additionally received 7days of daily treatment with polychromatic light on the sacral area, D=15cm. The PT course began on the day after mastectomy (Bioptron-2 device; Switzerland, 480-3400nm, 95% polarization, 40mW/cm 2 , 24J/cm 2 ). Mastectomy produced many changes in cellular and humoral immunity, which was recorded on the 1st and 8th post-surgical days. The PT course resulted in a faster normalization of post-surgical leukocytosis and activation of cytotoxic CD8 + T-lymphocytes (Lym), reduced the elevated concentration in blood of immune complexes and in parallel promoted cytotoxic activity of CD16 + /CD56 + NK-cells. The PT up-regulated the number of NK-cells in patients with its decrease on the 1st post-surgical day and prevented the decrease in the amount of monocytes, CD19 + B-Lym, CD3 + T-Lym, CD4 + T-helpers, activated CD3 + /HLADR + T-Lym, and the decrease of the phagocytotic capability of neutrophils. PT blocked the down-regulation of the IgM, IgA concentration and abnormally sharp increase of the proinflammatory cytokine IFN-γ content. Therefore, a 7-day course with polychromatic light prevented the

  9. Engineering of Porphyrin Molecules for Use as Effective Cathode Interfacial Modifiers in Organic Solar Cells of Enhanced Efficiency and Stability.

    Science.gov (United States)

    Tountas, Marinos; Verykios, Apostolis; Polydorou, Ermioni; Kaltzoglou, Andreas; Soultati, Anastasia; Balis, Nikolaos; Angaridis, Panagiotis A; Papadakis, Michael; Nikolaou, Vasilis; Auras, Florian; Palilis, Leonidas C; Tsikritzis, Dimitris; Evangelou, Evangelos K; Gardelis, Spyros; Koutsoureli, Matroni; Papaioannou, George; Petsalakis, Ioannis D; Kennou, Stella; Davazoglou, Dimitris; Argitis, Panagiotis; Falaras, Polycarpos; Coutsolelos, Athanassios G; Vasilopoulou, Maria

    2018-06-06

    In the present work, we effectively modify the TiO 2 electron transport layer of organic solar cells with an inverted architecture using appropriately engineered porphyrin molecules. The results show that the optimized porphyrin modifier bearing two carboxylic acids as the anchoring groups and a triazine electron-withdrawing spacer significantly reduces the work function of TiO 2 , thereby reducing the electron extraction barrier. Moreover, the lower surface energy of the porphyrin-modified substrate results in better physical compatibility between the latter and the photoactive blend. Upon employing porphyrin-modified TiO 2 electron transport layers in PTB7:PC 71 BM-based organic solar cells we obtained an improved average power conversion efficiency up to 8.73%. Importantly, porphyrin modification significantly increased the lifetime of the devices, which retained 80% of their initial efficiency after 500 h of storage in the dark. Because of its simplicity and efficacy, this approach should give tantalizing glimpses and generate an impact into the potential of porphyrins to facilitate electron transfer in organic solar cells and related devices.

  10. A stability study of polymer solar cells using conjugated polymers with different donor or acceptor side chain patterns

    DEFF Research Database (Denmark)

    Heckler, Ilona Maria; Kesters, Jurgen; Defour, Maxime

    2016-01-01

    -phenylethyl group. It is shown that the exchange of the hexyl chain on the DTBT moiety has a negative impact on the stability of the polymer as well as on the performance of the resulting PSCs. On the other hand, partial exchange of the 2-hexyldecyl side chain of the BDT unit by a 2-hydroxyethyl group results......)benzo[c][1,2,5]thiadiazole (DTBT), specifically selected because of its suitability for roll-coating in the ambient environment, is investigated in terms of operational stability via partial exchange (5 or 10%) of the alkyl side chain on either the donor or the acceptor monomer with a 2-hydroxyethyl or 2...

  11. Room-Temperature Atomic Layer Deposition of Al2 O3 : Impact on Efficiency, Stability and Surface Properties in Perovskite Solar Cells.

    Science.gov (United States)

    Kot, Malgorzata; Das, Chittaranjan; Wang, Zhiping; Henkel, Karsten; Rouissi, Zied; Wojciechowski, Konrad; Snaith, Henry J; Schmeisser, Dieter

    2016-12-20

    In this work, solar cells with a freshly made CH 3 NH 3 PbI 3 perovskite film showed a power conversion efficiency (PCE) of 15.4 % whereas the one with 50 days aged perovskite film only 6.1 %. However, when the aged perovskite was covered with a layer of Al 2 O 3 deposited by atomic layer deposition (ALD) at room temperature (RT), the PCE value was clearly enhanced. X-ray photoelectron spectroscopy study showed that the ALD precursors are chemically active only at the perovskite surface and passivate it. Moreover, the RT-ALD-Al 2 O 3 -covered perovskite films showed enhanced ambient air stability. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Solar Thermochemical Fuel Production via a Novel Low Pressure, Magnetically Stabilized, Non-volatile Iron Oxide Looping Process (University of Florida)

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, David W.

    2018-03-29

    The UF Solar Fuels team has developed a modular reactor at the 10kW scale for the thermochemical conversion of H2O and CO2 to H2 and CO, respectively, using concentrated solar energy to drive high-temperature redox reactions. Various materials, including ferrites, doped and mixed metal ferrites, and ceria, were investigated and reported on. Ceria was chosen as the reactive material, with thermogravimetric and bench-scale analysis concurring with literature review and pointing towards reasonable kinetics and stability at temperatures on the order of 1500 °C. A combined radiation, conduction, and species reaction/mass transport model was developed, utilizing Monte Carlo ray tracing, Lattice Boltzmann, and random walk particle tracking for the respective components to direct development and optimization of the reactor. With experimental data used for reaction rates, the model showed a path to efficiencies >20%, which could be market competitive with current PV-hydrolysis hydrogen generation systems. Economic analysis of a larger-scale plant (100kW modular system with cost performed at 500 modules) has been performed, assuming 0.5% and 10% internal rate of return. Without compression costs, H2 production cost using this is technology at $12/kg H2 and $17/kg H2 for realized efficiencies of 20% and 15%, respectively. An interaction of ceria and alumina, with the formation of CeAlO3 occurring at ~1700 °C, had been reported in the literature, but the UF Solar Fuels team observed and reported on it at a large scale, confirming its presence as an engineering consideration when working ceria and alumina at extreme temperatures. CeAlO3 could be being produced at lower temperatures due to the oxidation and reducing environments or due to local hotspots in the reactor. A solar thermogravimeter was developed, to take advantage of the high heating rates available at the UF Solar Simulator Facility to allow investigation of species evolution and material stability in extreme

  13. Nearly constant ratio between the proton inertial scale and the spectrum break length scale in the plasma beta range from 0.2 to 1.4 in the solar wind turbulence

    Science.gov (United States)

    Wang, X.; Tu, C. Y.; He, J.; Wang, L.

    2017-12-01

    The spectrum break at the ion scale of the solar wind magnetic fluctuations are considered to give important clue on the turbulence dissipation mechanism. Among several possible mechanisms, the most notable ones are the two mechanisms that related respectively with proton thermal gyro-radius and proton inertial length. However, no definite conclusion has been given for which one is more reasonable because the two parameters have similar values in the normal plasma beta range. Here we do a statistical study for the first time to see if the two mechanism predictions have different dependence on the solar wind velocity and on the plasma beta in the normal plasma beta range in the solar wind at 1 AU. From magnetic measurements by Wind, Ulysses and Messenger, we select 60 data sets with duration longer than 8 hours. We found that the ratio between the proton inertial scale and the spectrum break scale do not change considerably with both varying the solar wind speed from 300km/s to 800km/s and varying the plasma beta from 0.2 to 1.4. The average value of the ratio times 2pi is 0.46 ± 0.08. However, the ratio between the proton gyro-radius and the break scale changes clearly. This new result shows that the proton inertial scale could be a single factor that determines the break length scale and hence gives a strong evidence to support the dissipation mechanism related to it in the normal plasma beta range. The value of the constant ratio may relate with the dissipation mechanism, but it needs further theoretical study to give detailed explanation.

  14. A Biopolymer Heparin Sodium Interlayer Anchoring TiO2 and MAPbI3 Enhances Trap Passivation and Device Stability in Perovskite Solar Cells.

    Science.gov (United States)

    You, Shuai; Wang, Hui; Bi, Shiqing; Zhou, Jiyu; Qin, Liang; Qiu, Xiaohui; Zhao, Zhiqiang; Xu, Yun; Zhang, Yuan; Shi, Xinghua; Zhou, Huiqiong; Tang, Zhiyong

    2018-04-18

    Traps in the photoactive layer or interface can critically influence photovoltaic device characteristics and stabilities. Here, traps passivation and retardation on device degradation for methylammonium lead trihalide (MAPbI 3 ) perovskite solar cells enabled by a biopolymer heparin sodium (HS) interfacial layer is investigated. The incorporated HS boosts the power conversion efficiency from 17.2 to 20.1% with suppressed hysteresis and Shockley-Read-Hall recombination, which originates primarily from the passivation of traps near the interface between the perovskites and the TiO 2 cathode. The incorporation of an HS interfacial layer also leads to a considerable retardation of device degradation, by which 85% of the initial performance is maintained after 70 d storage in ambient environment. Aided by density functional theory calculations, it is found that the passivation of MAPbI 3 and TiO 2 surfaces by HS occurs through the interactions of the functional groups (COO - , SO 3 - , or Na + ) in HS with undersaturated Pb and I ions in MAPbI 3 and Ti 4+ in TiO 2 . This work demonstrates a highly viable and facile interface strategy using biomaterials to afford high-performance and stable perovskite solar cells. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Solar electricity and solar fuels

    Science.gov (United States)

    Spiers, David J.

    1989-04-01

    The nature of solar radiation and its variation with location is described. The distribution of energy in the solar spectrum places immediate limits on the theoretical efficiency of conversion processes, since practical absorbers cannot convert all wavelengths received to useful energy. The principles of solar energy conversion methods are described. Absorption of solar energy can give rise to direct electrical generation, heating, or chemical change. Electrical generation from sunlight can be achieved by photovoltaic systems directly or by thermal systems which use solar heat to drive a heat engine and generator. The technology used and under research for promising ways of producing electricity or fuel from solar energy is described. Photovoltaic technology is established today for remote area, small power applications, and photovoltaic module sales alone are over 100 million dollars per year at present. The photovoltaic market has grown steadily since the mid-1970's, as prices have fallen continuously. Future energy options are briefly described. The merits of a sustainable energy economy, based on renewable energy resources, including solar energy, are emphasized, as this seems to provide the only hope of eliminating the problems caused by the build-up of atmospheric carbon dioxide, acid rain pollution and nuclear waste disposal. There is no doubt that clean fuels which were derived from solar energy and either did not involve carbon dioxide and used atmospheric carbon dioxide as the source dioxide as the source of carbon would be a worthy ideal. Methods described could one day achieve this.

  16. Functional solid additive modified PEDOT:PSS as an anode buffer layer for enhanced photovoltaic performance and stability in polymer solar cells

    Science.gov (United States)

    Xu, Binrui; Gopalan, Sai-Anand; Gopalan, Anantha-Iyengar; Muthuchamy, Nallal; Lee, Kwang-Pill; Lee, Jae-Sung; Jiang, Yu; Lee, Sang-Won; Kim, Sae-Wan; Kim, Ju-Seong; Jeong, Hyun-Min; Kwon, Jin-Beon; Bae, Jin-Hyuk; Kang, Shin-Won

    2017-01-01

    Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is most commonly used as an anode buffer layer in bulk-heterojunction (BHJ) polymer solar cells (PSCs). However, its hygroscopic and acidic nature contributes to the insufficient electrical conductivity, air stability and restricted photovoltaic (PV) performance for the fabricated PSCs. In this study, a new multifunctional additive, 2,3-dihydroxypyridine (DOH), has been used in the PEDOT: PSS buffer layer to obtain modified properties for PEDOT: PSS@DOH and achieve high PV performances. The electrical conductivity of PEDOT:PSS@DOH films was markedly improved compared with that of PEDOT:PSS. The PEDOT:PSS@DOH film exhibited excellent optical characteristics, appropriate work function alignment, and good surface properties in BHJ-PSCs. When a poly(3-hexylthiohpene):[6,6]-phenyl C61-butyric acid methyl ester blend system was applied as the photoactive layer, the power conversion efficiency of the resulting PSCs with PEDOT:PSS@DOH(1.0%) reached 3.49%, outperforming pristine PEDOT:PSS, exhibiting a power conversion enhancement of 20%. The device fabricated using PEDOT:PSS@DOH (1.0 wt%) also exhibited improved thermal and air stability. Our results also confirm that DOH, a basic pyridine derivative, facilitates adequate hydrogen bonding interactions with the sulfonic acid groups of PSS, induces the conformational transformation of PEDOT chains and contributes to the phase separation between PEDOT and PSS chains. PMID:28338088

  17. Core/Shell Structured TiO2/CdS Electrode to Enhance the Light Stability of Perovskite Solar Cells.

    Science.gov (United States)

    Hwang, Insung; Baek, Minki; Yong, Kijung

    2015-12-23

    In this work, enhanced light stability of perovskite solar cell (PSC) achieved by the introduction of a core/shell-structured CdS/TiO2 electrode and the related mechanism are reported. By a simple solution-based process (SILAR), a uniform CdS shell was coated onto the surface of a TiO2 layer, suppressing the activation of intrinsic trap sites originating from the oxygen vacancies of the TiO2 layer. As a result, the proposed CdS-PSC exhibited highly improved light stability, maintaining nearly 80% of the initial efficiency after 12 h of full sunlight illumination. From the X-ray diffraction analyses, it is suggested that the degradation of the efficiency of PSC during illumination occurs regardless of the decomposition of the perovskite absorber. Considering the light-soaking profiles of the encapsulated cells and the OCVD characteristics, it is likely that the CdS shell had efficiently suppressed the undesirable electron kinetics, such as trapping at the surface defects of the TiO2 and preventing the resultant charge losses by recombination. This study suggests that further complementary research on various effective methods for passivation of the TiO2 layer would be highly meaningful, leading to insight into the fabrication of PSCs stable to UV-light for a long time.

  18. Highly Efficient LiYF4:Yb(3+), Er(3+) Upconversion Single Crystal under Solar Cell Spectrum Excitation and Photovoltaic Application.

    Science.gov (United States)

    Chen, Xu; Xu, Wen; Song, Hongwei; Chen, Cong; Xia, Haiping; Zhu, Yongsheng; Zhou, Donglei; Cui, Shaobo; Dai, Qilin; Zhang, Jiazhong

    2016-04-13

    Luminescent upconversion is a promising way to harvest near-infrared (NIR) sunlight and transforms it into visible light that can be directly absorbed by active materials of solar cells and improve their power conversion efficiency (PCE). However, it is still a great challenge to effectively improve the PCE of solar cells with the assistance of upconversion. In this work, we demonstrate the application of the transparent LiYF4:Yb(3+), Er(3+) single crystal as an independent luminescent upconverter to improve the PCE of perovskite solar cells. The LiYF4:Yb(3+), Er(3+) single crystal is prepared by an improved Bridgman method, and its internal quantum efficiency approached to 5.72% under 6.2 W cm(-2) 980 nm excitation. The power-dependent upconversion luminescence indicated that under the excitation of simulated sunlight the (4)F(9/2)-(4)I(15/2) red emission originally results from the cooperation of a 1540 nm photon and a 980 nm photon. Furthermore, when the single crystal is placed in front of the perovskite solar cells, the PCE is enhanced by 7.9% under the irradiation of simulated sunlight by 7-8 solar constants. This work implies the upconverter not only can serve as proof of principle for improving PCE of solar cells but also is helpful to practical application.

  19. High-stability Ti{sup 4+} precursor for the TiO{sub 2} compact layer of dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Qinghua; Cong, Shan; Wang, Hao; Wang, Yun; Dai, Xiao; Zhao, Jie; Sun, Yinghui; Lou, Yanhui; Zou, Guifu, E-mail: zouguifu@suda.edu.cn

    2015-11-30

    Graphical abstract: - Highlights: • We developed an aqueous polymer-assisted deposition method to improve the chemical stability of the TiCl{sub 4} aqueous solution. • The Ti{sup 4+} is encapsulated by the polymer can maintain their initial performances for several months. • The film is dense, smooth and uniform, preparing by this method. • The power conversion efficiency of the DSSC based on P-TiO{sub 2} compact film is about 12.5% higher than that based on H-TiO{sub 2}. - Abstract: A compact layer (blocking layer) can effectively block the direct contact between the fluorine-doped tin oxide (FTO) glass substrate and electrolyte in dye-sensitized solar cells (DSSCs). The TiCl{sub 4} hydrolysis has been widely adopted for preparing the TiO{sub 2} compact layer (H-TiO{sub 2}). However, the TiCl{sub 4} aqueous solution is unstable for its high reactivity. To improve the chemical stability of TiCl{sub 4} aqueous solution, the Ti{sup 4+} is encapsulated by the polymer, polyethyleneimine (PEI). Experimentals show that the Ti-PEI precursor solution can maintain their initial performances for several months. The resulting TiO{sub 2} film (P-TiO{sub 2}) grown by the Ti-PEI precursor is dense, smooth and uniform without any visible and detectable cracks or voids. The P-TiO{sub 2} compact layer is even denser than the H-TiO{sub 2} compact layer, suggesting reducing the electron recombination and prolonging the electron lifetime in dye-sensitized solar cells. Indeed, the electron lifetime of the DSSC based on the P-TiO{sub 2} is 13.15 ms, which is longer than the 10.83 ms based on H-TiO{sub 2}. Meanwhile, the power conversion efficiency of the DSSC based on P-TiO{sub 2} compact film is about 12.5% higher than that based on H-TiO{sub 2}. Therefore, this encapsulation technology can not only improve the stability of the metal ions solution but also meet a large-scale fabrication demand of the TiO{sub 2} compact layer in future DSSCs.

  20. Solar sail deployment experiment

    OpenAIRE

    Shimose, Shigeru; 下瀬 滋

    2006-01-01

    Solar Sail move by receiving momentum of photons in sunlight. This paper presents results of some Spin-Stabilized Solar Sail deployment experiment. ISAS has successfully deployed, for the first time in the world, the polyimide Solar Sail taking advantage of centrifugal force in space. Based on this result, the new deployment mechanism is being developed which retracts the 50 m diameter sail.

  1. Improving the Long-Term Stability of Perovskite Solar Cells with a Porous Al 2 O 3 Buffer Layer

    KAUST Repository

    Guarnera, Simone; Abate, Antonio; Zhang, Wei; Foster, Jamie M.; Richardson, Giles; Petrozza, Annamaria; Snaith, Henry J.

    2015-01-01

    © 2015 American Chemical Society. Hybrid perovskites represent a new paradigm for photovoltaics, which have the potential to overcome the performance limits of current technologies and achieve low cost and high versatility. However, an efficiency drop is often observed within the first few hundred hours of device operation, which could become an important issue. Here, we demonstrate that the electrode's metal migrating through the hole transporting material (HTM) layer and eventually contacting the perovskite is in part responsible for this early device degradation. We show that depositing the HTM within an insulating mesoporous "buffer layer" comprised of Al2O3 nanoparticles prevents the metal electrode migration while allowing for precise control of the HTM thickness. This enables an improvement in the solar cell fill factor and prevents degradation of the device after 350 h of operation. (Graph Presented).

  2. New iridium complex as additive to the spiro-OMeTAD in perovskite solar cells with enhanced stability

    Directory of Open Access Journals (Sweden)

    Laura Badia

    2014-08-01

    Full Text Available A new iridium complex, IrCp*Cl(PyPyz[TFSI], has been synthesized and used as additive for the hole transporter material, spiro-OMeTAD, in perovskite solar cells. The cells prepared with this Ir additive present higher efficiency than reference cells, and similar to cells prepared with Co additive. We have determined that the presence of metal complexes as additives decreases the recombination rate, as it has been observed by impedance spectroscopy. Very interestingly, while the efficiency after 3 months decreases by 22% and 70% for reference cell and cell with Co additive, respectively, the efficiency of devices containing the Ir additive is only decreased by a 4%.

  3. Improving the Long-Term Stability of Perovskite Solar Cells with a Porous Al 2 O 3 Buffer Layer

    KAUST Repository

    Guarnera, Simone

    2015-02-05

    © 2015 American Chemical Society. Hybrid perovskites represent a new paradigm for photovoltaics, which have the potential to overcome the performance limits of current technologies and achieve low cost and high versatility. However, an efficiency drop is often observed within the first few hundred hours of device operation, which could become an important issue. Here, we demonstrate that the electrode\\'s metal migrating through the hole transporting material (HTM) layer and eventually contacting the perovskite is in part responsible for this early device degradation. We show that depositing the HTM within an insulating mesoporous "buffer layer" comprised of Al2O3 nanoparticles prevents the metal electrode migration while allowing for precise control of the HTM thickness. This enables an improvement in the solar cell fill factor and prevents degradation of the device after 350 h of operation. (Graph Presented).

  4. Solar neutrinos

    International Nuclear Information System (INIS)

    Phillips, R.J.N.

    1987-09-01

    The problem with solar neutrinos is that there seem to be too few of them, at least near the top end of the spectrum, since the 37 Cl detector finds only about 35% of the standard predicted flux. Various kinds of explanation have been offered: (a) the standard solar model is wrong, (b) neutrinos decay, (c) neutrinos have magnetic moments, (d) neutrinos oscillate. The paper surveys developments in each of these areas, especially the possible enhancement of neutrino oscillations by matter effects and adiabatic level crossing. The prospects for further independent experiments are also discussed. (author)

  5. Metamaterial Receivers for High Efficiency Concentrated Solar Energy Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Yellowhair, Julius E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Concentrating Solar Technologies Dept.; Kwon, Hoyeong [Univ. of Texas, Austin, TX (United States). Dept. of Electrical and Computer Engineering; Alu, Andrea [Univ. of Texas, Austin, TX (United States). Dept. of Electrical and Computer Engineering; Jarecki, Robert L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Concentrating Solar Technologies Dept.; Shinde, Subhash L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Concentrating Solar Technologies Dept.

    2016-09-01

    Operation of concentrated solar power receivers at higher temperatures (>700°C) would enable supercritical carbon dioxide (sCO2) power cycles for improved power cycle efficiencies (>50%) and cost-effective solar thermal power. Unfortunately, radiative losses at higher temperatures in conventional receivers can negatively impact the system efficiency gains. One approach to improve receiver thermal efficiency is to utilize selective coatings that enhance absorption across the visible solar spectrum while minimizing emission in the infrared to reduce radiative losses. Existing coatings, however, tend to degrade rapidly at elevated temperatures. In this report, we report on the initial designs and fabrication of spectrally selective metamaterial-based absorbers for high-temperature, high-thermal flux environments important for solarized sCO2 power cycles. Metamaterials are structured media whose optical properties are determined by sub-wavelength structural features instead of bulk material properties, providing unique solutions by decoupling the optical absorption spectrum from thermal stability requirements. The key enabling innovative concept proposed is the use of structured surfaces with spectral responses that can be tailored to optimize the absorption and retention of solar energy for a given temperature range. In this initial study through the Academic Alliance partnership with University of Texas at Austin, we use Tungsten for its stability in expected harsh environments, compatibility with microfabrication techniques, and required optical performance. Our goal is to tailor the optical properties for high (near unity) absorptivity across the majority of the solar spectrum and over a broad range of incidence angles, and at the same time achieve negligible absorptivity in the near infrared to optimize the energy absorbed and retained. To this goal, we apply the recently developed concept of plasmonic Brewster angle to suitably designed

  6. Integrated MoSe2 with n+p-Si photocathodes for solar water splitting with high efficiency and stability

    Science.gov (United States)

    Huang, Guanping; Mao, Jie; Fan, Ronglei; Yin, Zhihao; Wu, Xi; Jie, Jiansheng; Kang, Zhenhui; Shen, Mingrong

    2018-01-01

    Many earth-abundant transition metal dichalcogenides (TMDs) have been employed as catalysts for H2 evolution reaction (HER); however, their impactful integration onto photocathodes for photoelectrochemical (PEC) HER is less developed. In this study, we directly sputtered a MoSe2 catalyst onto an n+p-Si photocathode for efficient and stable PEC-HER. An onset potential of 0.4 V vs. RHE, a saturated photocurrent of 29.3 mA/cm2, a fill factor of 0.32, and an energy conversion efficiency of 3.8% were obtained under 100 mA/cm2 Xe lamp illumination. Such superior PEC properties were ascribed to the nearly vertically standing two dimensional MoSe2 rough surface layer and the sharp interface between Si and MoSe2 with small charge transfer resistance. The balance between the reflectivity of the electrode surface and the absorptivity of MoSe2 was also discussed. In addition, the MoSe2 layer can protect the n+p-Si photocathode with a 120 h stability due to its initial growth on Si with high flatness and compactness. This study provides a path to the effective and scalable growth of TMDs onto the Si photocathode aiming for high efficiency and stability.

  7. Development of polymers for large scale roll-to-roll processing of polymer solar cells

    DEFF Research Database (Denmark)

    Carlé, Jon Eggert

    Development of polymers for large scale roll-to-roll processing of polymer solar cells Conjugated polymers potential to both absorb light and transport current as well as the perspective of low cost and large scale production has made these kinds of material attractive in solar cell research....... The research field of polymer solar cells (PSCs) is rapidly progressing along three lines: Improvement of efficiency and stability together with the introduction of large scale production methods. All three lines are explored in this work. The thesis describes low band gap polymers and why these are needed....... Polymer of this type display broader absorption resulting in better overlap with the solar spectrum and potentially higher current density. Synthesis, characterization and device performance of three series of polymers illustrating how the absorption spectrum of polymers can be manipulated synthetically...

  8. Investigation of stability and x-ray spectrum in gas-puff z-pinch plasmas diriven by inductive energy storage pulsed power generator with a plasma opening switch

    Energy Technology Data Exchange (ETDEWEB)

    Murayama, K.; Fukudome, I. [Yatsushiro National College of Technology, Dept. of Mechanical and Electrical Engineering, Yatsushiro, Kumamoto (Japan); Teramoto, Y.; Katsuki, S.; Akiyama, H. [Kumamoto Univ., Dept. of Electrical and Computer Engineering, Kumamoto (Japan)

    2002-06-01

    Gas-puff z-pinch plasmas are driven by an inductive voltage adder - inductive energy storage pulsed power generator ''ASO-X''. ASO-X has the performance of the maximum output voltage and current are 180 kV and 400 kA respectively and can provide a fast rise time current with operating POS. The stability of the plasma column, spectrum radiated from z-pinch plasmas and the spatial distribution of hot spots are investigated in the case with and without operating POS. By driving ASO-X with operating POS the kink instability is restrained and the stability of plasma column is improved about three times in regard to the average dispersion. Furthermore the duration of soft x-ray radiation is increased and the spatial distribution of hot spots is 50% improved with regard to kurtosis of the intensity profile of pinhole photographs compared to those without operating POS. (author)

  9. Investigation of stability and x-ray spectrum in gas-puff z-pinch plasmas diriven by inductive energy storage pulsed power generator with a plasma opening switch

    International Nuclear Information System (INIS)

    Murayama, K.; Fukudome, I.; Teramoto, Y.; Katsuki, S.; Akiyama, H.

    2002-01-01

    Gas-puff z-pinch plasmas are driven by an inductive voltage adder - inductive energy storage pulsed power generator ''ASO-X''. ASO-X has the performance of the maximum output voltage and current are 180 kV and 400 kA respectively and can provide a fast rise time current with operating POS. The stability of the plasma column, spectrum radiated from z-pinch plasmas and the spatial distribution of hot spots are investigated in the case with and without operating POS. By driving ASO-X with operating POS the kink instability is restrained and the stability of plasma column is improved about three times in regard to the average dispersion. Furthermore the duration of soft x-ray radiation is increased and the spatial distribution of hot spots is 50% improved with regard to kurtosis of the intensity profile of pinhole photographs compared to those without operating POS. (author)

  10. Relations between Structure, Activity and Stability in C3N4 Based Photocatalysts Used for Solar Hydrogen Production

    Directory of Open Access Journals (Sweden)

    Ramesh P. Sivasankaran

    2018-01-01

    Full Text Available Solar hydrogen production from water could be a sustainable and environmentally friendly alternative to fossil energy carriers, yet so far photocatalysts active and stable enough for large-scale applications are not available, calling for advanced research efforts. In this work, H2 evolution rates of up to 1968 and 5188 μmol h−1 g−1 were obtained from aqueous solutions of triethanolamine (TEOA and oxalic acid (OA, respectively, by irradiating composites of AgIn5S8 (AIS, mesoporous C3N4 (CN, surface area >150 m2/g and ≤2 wt.% in-situ photodeposited Pt nanoparticles (NPs with UV-vis (≥300 nm and pure visible light (≥420 nm. Structural properties and electron transport in these materials were analyzed by XRD, STEM-HAADF, XPS, UV-vis-DRS, ATR-IR, photoluminescence and in situ-EPR spectroscopy. Initial H2 formation rates were highest for Pt/CN, yet with TEOA this catalyst deactivated by inclusion of Pt NPs in the matrix of CN (most pronounced at λ ≥ 300 nm while it remained active with OA, since in this case Pt NPs were enriched on the outermost surface of CN. In Pt/AIS-CN catalysts, Pt NPs were preferentially deposited on the surface of the AIS phase which prevents them from inclusion in the CN phase but reduces simultaneously the initial H2 evolution rate. This suggests that AIS hinders transport of separated electrons from the CN conduction band to Pt NPs but retains the latter accessible by protons to produce H2.

  11. Effect of hole-transporting materials on the photovoltaic performance and stability of all-ambient-processed perovskite solar cells

    Institute of Scientific and Technical Information of China (English)

    Nanaji Islavath; S Saroja; K Srinivas Reddy; P C Harikesh; G Veerappan; Shrikant V Joshi; Easwaramoorthi Ramasamy

    2017-01-01

    High-efficiency perovskite solar cells (PSCs) reported hitherto have been mostly prepared in a moisture and oxygen-free glove-box atmosphere,which hampers upscaling and real-time performance assessment of this exciting photovoltaic technology.In this work,we have systematically studied the feasibility of allambient-processing of PSCs and evaluated their photovoltaic performance.It has been shown that phasepure crystalline tetragonal MAPbI3 perovskite films are instantly formed in ambient air at room temperature by a two-step spin coating process,undermining the need for dry atmosphere and post-annealing.All-ambient-processed PSCs with a configuration of FTO/TiO2/MAPbI3/Spiro-OMeTAD/Au achieve opencircuit voltage (990 mV) and short-circuit current density (20.31 mA/cm2) comparable to those of best reported glove-box processed devices.Nevertheless,device power conversion efficiency is still constrained at 5% by the unusually low fill-factor of 0.25.Dark current-voltage characteristics reveal poor conductivity of hole-transporting layer caused by lack of oxidized spiro-OMeTAD species,resulting in high seriesresistance and decreased fill-factor,The study also establishes that the above limitations can be readily overcome by employing an inorganic p-type semiconductor,copper thiocyanate,as ambient-processable hole-transporting layer to yield a fill-factor of 0.54 and a power conversion efficiency of 7.19%.The present findings can have important implications in industrially viable fabrication of large-area PSCs.

  12. The isotopic abundance ratio 12C/13C in the solar atmosphere determined from CH-lines in the photospheric spectrum

    International Nuclear Information System (INIS)

    Iversen, Oe.

    1976-01-01

    The R-branch of the (0,0) vibrational band of the violet electronic transition A 2 Δ-X 2 PI of CH is analysed. Isotope wavelength shifts were measured on laboratory spectrograms. The method of synthesising the spectrum was used, and the molecular dissociation equilibrium through the photosphere was computed. 13 CH is not definitely identified in the photospheric spectrum and only upper limits of the 13 C abundance are deduced. The upper limits are sensitive to the local continuum level. A photospheric abundance ratio 12 C/ 13 C greater than the terrestrial value of 90 seems highly probable. (Auth.)

  13. Ni-doped α-Fe 2 O 3 as electron transporting material for planar heterojunction perovskite solar cells with improved efficiency, reduced hysteresis and ultraviolet stability

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Ying; Liu, Tao; Wang, Ning; Luo, Qiang; Lin, Hong; Li, Jianbao; Jiang, Qinglong; Wu, Lili; Guo, Zhanhu

    2017-08-01

    We report on high-efficiency planar heterojunction perovskite solar cells (PSCs) employing Ni-doped alpha-Fe2O3 as electron-transporting layer (ETL). The suitable addition of nickel (Ni) dopant could enhance the electron conductivity as well as induce downward shift of the conduction band minimum for alpha-Fe2O3, which facilitate electrons injection and transfer from the conduction band of the perovskite. As a consequence, a substantial reduction in the charge accumulation at the perovskite/ETL interface makes the device much less sensitive to scanning rate and direction, i.e., lower hysteresis. With a reverse scan for the optimized PSC under standard AM-1.5 sunlight illumination, it generates a competitive power conversion efficiency (PCE) of 14.2% with a large short circuit current (J(sc)) of 22.35 mA/cm(2), an open circuit photovoltage (V-oc) of 0.92 V and a fill factor (FF) of 69.1%. Due to the small J-V hysteresis behavior, a higher stabilized PCE up to 11.6% near the maximum power point can be reached for the device fabricated with 4 mol% Ni-doped alpha-Fe2O3 ETL compared with the undoped alpha-Fe2O3 based cell (9.2%). Furthermore, a good stability of devices with exposure to ambient air and high levels of ultraviolet (UV)-light can be achieved. Overall, our results demonstrate that the simple solution-processed Ni-doped alpha-Fe2O3 can be a good candidate of the n-type collection layer for commercialization of PSCs.

  14. Solar Neutrinos

    Directory of Open Access Journals (Sweden)

    V. Antonelli

    2013-01-01

    relevant indications on the fundamental interactions among particles. After reviewing the striking results of the last two decades, which were determinant to solve the long standing solar neutrino puzzle and refine the Standard Solar Model, we focus our attention on the more recent results in this field and on the experiments presently running or planned for the near future. The main focus at the moment is to improve the knowledge of the mass and mixing pattern and especially to study in detail the lowest energy part of the spectrum, which represents most of the solar neutrino spectrum but is still a partially unexplored realm. We discuss this research project and the way in which present and future experiments could contribute to make the theoretical framework more complete and stable, understanding the origin of some “anomalies” that seem to emerge from the data and contributing to answer some present questions, like the exact mechanism of the vacuum to matter transition and the solution of the so-called solar metallicity problem.

  15. Surface Grafting of Ru(II) Diazonium-Based Sensitizers on Metal Oxides Enhances Alkaline Stability for Solar Energy Conversion.

    Science.gov (United States)

    Bangle, Rachel; Sampaio, Renato N; Troian-Gautier, Ludovic; Meyer, Gerald J

    2018-01-24

    The electrografting of [Ru(ttt)(tpy-C 6 H 4 -N 2 + )] 3+ , where "ttt" is 4,4',4″-tri-tert-butyl-2,2':6',2″-terpyridine, was investigated on several wide band gap metal oxide surfaces (TiO 2 , SnO 2 , ZrO 2 , ZnO, In 2 O 3 :Sn) and compared to structurally analogous sensitizers that differed only by the anchoring group, i.e., -PO 3 H 2 and -COOH. An optimized procedure for diazonium electrografting to semiconductor metal oxides is presented that allowed surface coverages that ranged between 4.7 × 10 -8 and 10.6 × 10 -8 mol cm -2 depending on the nature of the metal oxide. FTIR analysis showed the disappearance of the diazonium stretch at 2266 cm -1 after electrografting. XPS analysis revealed a characteristic peak of Ru 3d at 285 eV as well as a peak at 531.6 eV that was attributed to O 1s in Ti-O-C bonds. Photocurrents were measured to assess electron injection efficiency of these modified surfaces. The electrografted sensitizers exhibited excellent stability across a range of pHs spanning from 1 to 14, where classical binding groups such as carboxylic and phosphonic derivatives were hydrolyzed.

  16. Improving the efficiency and environmental stability of inverted planar perovskite solar cells via silver-doped nickel oxide hole-transporting layer

    Science.gov (United States)

    Wei, Ying; Yao, Kai; Wang, Xiaofeng; Jiang, Yihua; Liu, Xueyuan; Zhou, Naigen; Li, Fan

    2018-01-01

    In this paper, we demonstrate the high-performance inverted planar heterojunction perovskite solar cells (PeSCs) based on the novel inorganic hole-transporting layer (HTL) of silver (Ag)-doped NiOx (Ag:NiOx). Density-functional theory (DFT) calculation reveals that Ag prefers to occupy the substitutional Ni site (AgNi) and behaves as an acceptor in NiO lattice. Compared with the pristine NiOx films, appropriate Ag doping can increase the optical transparency, work function, electrical conductivity and hole mobility of NiOx films. Moreover, the CH3NH3PbI3 perovskite films grown on Ag:NiOx exhibit better crystallinity, higher coverage and smoother surface with densely packed larger grains than those grown on the pristine NiOx film. Consequently, the Ag:NiOx HTL boosts the efficiency of the inverted planar heterojunction PeSCs from 13.46% (for the pristine NiOx-based device) to 16.86% (for the 2 at.% Ag:NiOx-based device). Furthermore, the environmental stability of PeSCs based on Ag:NiOx HTL is dramatically improved compared to devices based on organic HTLs and pristine NiOx HTLs. This work provides a simple and effective HTL material system for high-efficient and stable PeSCs.

  17. Incorporating C60 as Nucleation Sites Optimizing PbI2 Films To Achieve Perovskite Solar Cells Showing Excellent Efficiency and Stability via Vapor-Assisted Deposition Method.

    Science.gov (United States)

    Chen, Hai-Bin; Ding, Xi-Hong; Pan, Xu; Hayat, Tasawar; Alsaedi, Ahmed; Ding, Yong; Dai, Song-Yuan

    2018-01-24

    To achieve high-quality perovskite solar cells (PSCs), the morphology and carrier transportation of perovskite films need to be optimized. Herein, C 60 is employed as nucleation sites in PbI 2 precursor solution to optimize the morphology of perovskite films via vapor-assisted deposition process. Accompanying the homogeneous nucleation of PbI 2 , the incorporation of C 60 as heterogeneous nucleation sites can lower the nucleation free energy of PbI 2 , which facilitates the diffusion and reaction between PbI 2 and organic source. Meanwhile, C 60 could enhance carrier transportation and reduce charge recombination in the perovskite layer due to its high electron mobility and conductivity. In addition, the grain sizes of perovskite get larger with C 60 optimizing, which can reduce the grain boundaries and voids in perovskite and prevent the corrosion because of moisture. As a result, we obtain PSCs with a power conversion efficiency (PCE) of 18.33% and excellent stability. The PCEs of unsealed devices drop less than 10% in a dehumidification cabinet after 100 days and remain at 75% of the initial PCE during exposure to ambient air (humidity > 60% RH, temperature > 30 °C) for 30 days.

  18. Co-sensitization of ZnO by CdS quantum dots in natural dye-sensitized solar cells with polymeric electrolytes to improve the cell stability

    Energy Technology Data Exchange (ETDEWEB)

    Junhom, W.; Magaraphan, R. [Polymer Processing and Polymer Nanomaterials Research Unit, Petroleum and Petrochemical College, Chulalongkorn University, Bangkok (Thailand)

    2015-05-22

    The CdS quantum dots (QDs) were deposited on ZnO layer by chemical bath deposition method to absorb light in the shorter wavelength region and used as photoanode in the dye sensitized solar cell (DSSCs) with natural dye extracted from Noni leaves. Microstructures of CdS-ZnO from various dipping time were characterized by XRD, FE-SEM and EDX. The results showed that the CdS is hexagonal structure and the amount of CdS increases when the dipping time increases. The maximal conversion efficiency of 0.292% was achieved by the DSSCs based on CdS QDs-sensitized ZnO film obtained from 9 min-dipping time. Furthermore, the stability of DSSCs was improved by using polymeric electrolyte. Poly (acrylic acid) (PAA) and Polyacrylamide (PAM) were introduced to CdS QDs-sensitized ZnO film from 9 min-dipping time. Each polymeric electrolyte was prepared by swelling from 0.1-2.0 %w in H2O. The maximal conversion efficiency of 0.207% was achieved for DSSCs based on CdS QDs-sensitized ZnO film with PAM 1.0% and the conversion efficiency was decreased 25% when it was left for1 hr.

  19. Synthesis of hierarchical ZnV2O6 nanosheets with enhanced activity and stability for visible light driven CO2 reduction to solar fuels

    Science.gov (United States)

    Bafaqeer, Abdullah; Tahir, Muhammad; Amin, Nor Aishah Saidina

    2018-03-01

    Hierarchical nanostructures have lately garnered enormous attention because of their remarkable performances in energy storage and catalysis applications. In this study, novel hierarchical ZnV2O6 nanosheets, formulated by one-step solvothermal method, for enhanced photocatalytic CO2 reduction with H2O to solar fuels has been investigated. The structure and properties of the catalysts were characterized by XRD, FESEM, TEM, BET, UV-vis, Raman and PL spectroscopy. The hierarchical ZnV2O6 nanosheets show excellent performance towards photoreduction of CO2 with H2O to CH3OH, CH3COOH and HCOOH under visible light. The main product yield, CH3OH of 3253.84 μmol g-cat-1 was obtained over ZnV2O6, 3.4 times the amount of CH3OH produced over the ZnO/V2O5 composite (945.28 μmol g-cat-1). In addition, CH3OH selectivity of 39.96% achieved over ZnO/V2O5, increased to 48.78% in ZnV2O6 nanosheets. This significant improvement in photo-activity over ZnV2O6 structure was due to hierarchical structure with enhanced charge separation by V2O5. The obtained ZnV2O6 hierarchical nanosheets exhibited excellent photocatalytic stability for selective CH3OH production.

  20. Enhanced efficiency and air-stability of NiOX-based perovskite solar cells via PCBM electron transport layer modification with Triton X-100.

    Science.gov (United States)

    Lee, Kisu; Ryu, Jaehoon; Yu, Haejun; Yun, Juyoung; Lee, Jungsup; Jang, Jyongsik

    2017-11-02

    We modified phenyl-C61-butyric acid methyl ester (PCBM) for use as a stable, efficient electron transport layer (ETL) in inverted perovskite solar cells (PSCs). PCBM containing a surfactant Triton X-100 acts as the ETL and NiO X nanocrystals act as a hole transport layer (HTL). Atomic force microscopy and scanning electron microscopy images showed that surfactant-modified PCBM (s-PCBM) forms a high-quality, uniform, and dense ETL on the rough perovskite layer. This layer effectively blocks holes and reduces interfacial recombination. Steady-state photoluminescence and electrochemical impedance spectroscopy analyses confirmed that Triton X-100 improved the electron extraction performance of PCBM. When the s-PCBM ETL was used, the average power conversion efficiency increased from 10.76% to 15.68%. This improvement was primarily caused by the increases in the open-circuit voltage and fill factor. s-PCBM-based PSCs also showed good air-stability, retaining 83.8% of their initial performance after 800 h under ambient conditions.

  1. Cu/sub x/S-CdS thin film solar cells - aftertreatment and stability. Cu/sub x/S-CdS Duennschicht-Solarzellen - Untersuchungen ueber die Nachbehandlung und die Stabilitaet

    Energy Technology Data Exchange (ETDEWEB)

    Pfisterer, F

    1987-02-19

    The performance of Cu/sub x/S-CdS thin film solar cells can be improved significantly by a secondary treatment of the Cu layer. The physical mechanisms underlying the aftertreatment process were investigated both experimentally and theoretically. A historical review is followed by an outline of the technology and theory of these solar cells (material properties, process engineering, photovoltaic properties) and a description of Cu aftertreatment and H glowing (experimental set-up, surface potential shift, electron beam scanning). Capacity measurements in this type of thin film cell are described (space charge profile, electrolytic decomposition, copper depletion between the contact web). Aftertreatment of the copper layer enhances the solar cell efficiency, stability, and productivity, makes the immersion process less tedious, and corrects the stoichiometry. (HWJ).

  2. Enhancement of the photoelectric performance in inverted bulk heterojunction solid solar cell with inorganic nanocrystals

    International Nuclear Information System (INIS)

    Luan, Weiling; Zhang, Chengxi; Luo, Lingli; Yuan, Binxia; Jin, Lin; Kim, Yong-Sang

    2017-01-01

    Highlights: • Solid solar cells based on FeS_2 or PbS NCs showed power conversion efficiency (PCE) of 3.0% and 3.11%, respectively. • The FeS_2 NCs/polymer solar cells showed good time and thermal stability when exposed in air condition. • Ternary solid solar cells based on PbS NCs exhibited a higher short circuit current density (J_s_c). - Abstract: Nanocrystal/polymer solid solar cells have the advantages of low-cost, simple process, and flexible manufacture. In this work, ternary solid solar cells based on FeS_2 and PbS nanocrystals exhibited photovoltaic conversion efficiency of 3.0% and 3.1%, respectively. As a kind of semiconductor with optical absorption in the visible and near-infrared regions, FeS_2 nanocrystals matched well with the solar radiation spectrum. Furthermore, PbS Nanocrystals could increase the number of electrons, due to its multiple exciton effect. Additionally, the FeS_2 nanocrystals solar cells showed high stability, with 83.3% of its initial efficiency remained after 15 weeks of exposure in air, and kept good stable performance at 20–80 °C. The photovoltaic conversion efficiency fluctuation magnitudes were also found to be smaller than quantum-dot sensitized solar cell under the same conditions.

  3. Physical interpretation of the angle-dependent magnetic helicity spectrum in the solar wind: The nature of turbulent fluctuations near the proton gyroradius scale

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Kristopher G.; Howes, Gregory G. [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States); TenBarge, Jason M. [IREAP, University of Maryland, College Park, MD 20742 (United States); Podesta, John J., E-mail: kristopher-klein@uiowa.edu [Center for Space Plasma Physics, Space Science Institute, Boulder, CO 80301 (United States)

    2014-04-20

    Motivated by recent observations of distinct parallel and perpendicular signatures in magnetic helicity measurements segregated by wave period and angle between the local magnetic field and the solar wind velocity, this paper undertakes a comparison of three intervals of Ulysses data with synthetic time series generated from a physically motivated turbulence model. From these comparisons, it is hypothesized that the observed signatures result from a perpendicular cascade of Alfvénic fluctuations and a local, non-turbulent population of ion-cyclotron or whistler waves generated by temperature anisotropy instabilities. By constraining the model's free parameters through comparison to in situ data, it is found that, on average, ∼95% of the power near dissipative scales is contained in a perpendicular Alfvénic cascade and that the parallel fluctuations are propagating nearly unidirectionally. The effects of aliasing on magnetic helicity measurements are considered and shown to be significant near the Nyquist frequency.

  4. Physical interpretation of the angle-dependent magnetic helicity spectrum in the solar wind: The nature of turbulent fluctuations near the proton gyroradius scale

    International Nuclear Information System (INIS)

    Klein, Kristopher G.; Howes, Gregory G.; TenBarge, Jason M.; Podesta, John J.

    2014-01-01

    Motivated by recent observations of distinct parallel and perpendicular signatures in magnetic helicity measurements segregated by wave period and angle between the local magnetic field and the solar wind velocity, this paper undertakes a comparison of three intervals of Ulysses data with synthetic time series generated from a physically motivated turbulence model. From these comparisons, it is hypothesized that the observed signatures result from a perpendicular cascade of Alfvénic fluctuations and a local, non-turbulent population of ion-cyclotron or whistler waves generated by temperature anisotropy instabilities. By constraining the model's free parameters through comparison to in situ data, it is found that, on average, ∼95% of the power near dissipative scales is contained in a perpendicular Alfvénic cascade and that the parallel fluctuations are propagating nearly unidirectionally. The effects of aliasing on magnetic helicity measurements are considered and shown to be significant near the Nyquist frequency.

  5. Spectrum Recombination.

    Science.gov (United States)

    Greenslade, Thomas B., Jr.

    1984-01-01

    Describes several methods of executing lecture demonstrations involving the recombination of the spectrum. Groups the techniques into two general classes: bringing selected portions of the spectrum together using lenses or mirrors and blurring the colors by rapid movement or foreshortening. (JM)

  6. Polychiral semiconducting carbon nanotube-fullerene solar cells.

    Science.gov (United States)

    Gong, Maogang; Shastry, Tejas A; Xie, Yu; Bernardi, Marco; Jasion, Daniel; Luck, Kyle A; Marks, Tobin J; Grossman, Jeffrey C; Ren, Shenqiang; Hersam, Mark C

    2014-09-10

    Single-walled carbon nanotubes (SWCNTs) have highly desirable attributes for solution-processable thin-film photovoltaics (TFPVs), such as broadband absorption, high carrier mobility, and environmental stability. However, previous TFPVs incorporating photoactive SWCNTs have utilized architectures that have limited current, voltage, and ultimately power conversion efficiency (PCE). Here, we report a solar cell geometry that maximizes photocurrent using polychiral SWCNTs while retaining high photovoltage, leading to record-high efficiency SWCNT-fullerene solar cells with average NREL certified and champion PCEs of 2.5% and 3.1%, respectively. Moreover, these cells show significant absorption in the near-infrared portion of the solar spectrum that is currently inaccessible by many leading TFPV technologies.

  7. Degradation of CIGS solar cells

    NARCIS (Netherlands)

    Theelen, M.J.

    2015-01-01

    Thin film CIGS solar cells and individual layers within these solar cells have been tested in order to assess their long term stability. Alongside with the execution of standard tests, in which elevated temperatures and humidity levels are used, the solar cells have also been exposed to a

  8. Dye stability and performances of dye-sensitized solar cells with different nitrogen additives at elevated temperatures - Can sterically hindered pyridines prevent dye degradation?

    Energy Technology Data Exchange (ETDEWEB)

    Tuyet Nguyen, Phuong; Lund, Torben [Department of Science, Systems and Models, Roskilde University, 4000 Roskilde (Denmark); Rand Andersen, Anders [University of Southern Denmark, Institute of Sensors, Signals and Electrotechnics (SENSE), Niels Bohrs Alle 1, 5230 Odense M (Denmark); Danish Technological Institute, Plastics Technology, Gregersensvej 2630 Taastrup (Denmark); Morten Skou, Eivind [University of Southern Denmark, Department of Chemical Engineering, Biotechnology and Enviromental Technology, Niels Bohrs Alle 1, 5230 Odense M (Denmark)

    2010-10-15

    The homogeneous kinetics of the nucleophilic substitution reactions between the ruthenium dye N719 and eight pyridines and 1-methylbenzimidazole have been investigated in 3-methoxypropionitrile at 100 C. The half lives of N719 with the additives 4-tert-butylpyridine (0.5 M) and 1-methylbenzimidazole (0.5 M) were 57 and 160 h, respectively. Sterically hindered pyridines like 2,6-lutidine did not react with N719. The efficiencies of dye-sensitized solar cells (DSC, area=8.0 cm{sup 2}) prepared with 1-methylbenzimidazole (MBI), 4-tert-butylpyridine (4-TBP), 2,6-lutidine and without any additive were 7.1%, 6.2%, 6.0% and 4.8%, respectively. The cells were stored in dark at 85 C and their I-V curves and impedance spectra were measured at regular time intervals. The N719 dye degradation in the cells were monitored by a new dye extraction protocol combined with analysis of the dye extract by HPLC coupled to mass spectrometry. After 300 h storage in dark at 85 C 40% of the initial amount of N719 dye was degraded in DSC cells prepared with MBI and the efficiency was decreased to 40% of its initial value. DSC cells prepared with 2,6-lutidine or no additives showed smaller thermal dye and efficiency stability at elevated temperatures than DSC cells prepared with the none sterically hindered additives MBI and 4-TBP. In the cells prepared with 2,6-lutidine or no additive higher contents of the iodo products [RuL{sub 2}(NCS)(iodide)]{sup +} and [RuL{sub 2}(3-MPN)(iodide)]{sup +} were found than in cells prepared with 4-TBP and MBI. It is suggested that sterically hindered pyridines have smaller complexation constants with I{sub 3}{sup -} than unsterically hindered additives. This may explain the observed faster nucleophilic substitution rates of uncomplexed I{sub 3}{sup -} with N719 in DSC cells prepared with sterically hindered pyridines. The EIS analysis showed that the lifetime of the injected electrons in the TiO{sub 2}{tau}{sub eff} is reduced by a thermally induced change

  9. Tm2+ luminescent materials for solar radiation conversion devices

    NARCIS (Netherlands)

    Van der Kolk, E.

    2015-01-01

    A solar radiation conversion device is described that comprises a luminescent Tm 2+ inorganic material for converting solar radiation of at least part of the UV and/or visible and/or infra red solar spectrum into infrared solar radiation, preferably said infrared solar radiation having a wavelength

  10. The use of polyurethane as encapsulating method for polymer solar cells—An inter laboratory study on outdoor stability in 8 countries

    DEFF Research Database (Denmark)

    Søndergaard, Roar; Makris, Theodoros; Lianos, Panagiotis

    2012-01-01

    A new encapsulation method for organic solar cells has been tested on flexible solar modules and cells embedded in polyurethane, sandwiched between a tempered glass plate and a polycarbonate plate. Panels, each containing 10 organic solar modules/cells, were fabricated and installed for outdoor...... exposure in eight different countries for 4½ months. In order to minimize potential deviations in procedures and equipment, one person was responsible for the fabrication, installation and initial and final IV-measurements of the panels using the same equipment for all measurements and calibrations...

  11. Chaotic solar oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Blacher, S; Perdang, J [Institut d' Astrophysique, B-4200 Cointe-Ougree (Belgium)

    1981-09-01

    A numerical experiment on Hamiltonian oscillations demonstrates the existence of chaotic motions which satisfy the property of phase coherence. It is observed that the low-frequency end of the power spectrum of such motions is remarkably similar in structure to the low-frequency SCLERA spectra. Since the smallness of the observed solar amplitudes is not a sufficient mathematical ground for inefficiency of non-linear effects the possibility of chaos among solar oscillations cannot be discarded a priori.

  12. National Community Solar Platform

    Energy Technology Data Exchange (ETDEWEB)

    Rupert, Bart [Clean Energy Collective, Louisville, CO (United States)

    2016-06-30

    This project was created to provide a National Community Solar Platform (NCSP) portal known as Community Solar Hub, that is available to any entity or individual who wants to develop community solar. This has been done by providing a comprehensive portal to make CEC’s solutions, and other proven community solar solutions, externally available for everyone to access – making the process easy through proven platforms to protect subscribers, developers and utilities. The successful completion of this project provides these tools via a web platform and integration APIs, a wide spectrum of community solar projects included in the platform, multiple groups of customers (utilities, EPCs, and advocates) using the platform to develop community solar, and open access to anyone interested in community solar. CEC’s Incubator project includes web-based informational resources, integrated systems for project information and billing systems, and engagement with customers and users by community solar experts. The combined effort externalizes much of Clean Energy Collective’s industry-leading expertise, allowing third parties to develop community solar without duplicating expensive start-up efforts. The availability of this platform creates community solar projects that are cheaper to build and cheaper to participate in, furthering the goals of DOE’s SunShot Initiative. Final SF 425 Final SF 428 Final DOE F 2050.11 Final Report Narrative

  13. Solar Indices - Solar Flares

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  14. Solar Indices - Solar Ultraviolet

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  15. Solar Indices - Solar Corona

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  16. Solar Indices - Solar Irradiance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  17. Solar Chameleons

    CERN Document Server

    Brax, Philippe

    2010-01-01

    We analyse the creation of chameleons deep inside the sun and their subsequent conversion to photons near the magnetised surface of the sun. We find that the spectrum of the regenerated photons lies in the soft X-ray region, hence addressing the solar corona problem. Moreover, these back-converted photons originating from chameleons have an intrinsic difference with regenerated photons from axions: their relative polarisations are mutually orthogonal before Compton interacting with the surrounding plasma. Depending on the photon-chameleon coupling and working in the strong coupling regime of the chameleons to matter, we find that the induced photon flux, when regenerated resonantly with the surrounding plasma, coincides with the solar flux within the soft X-ray energy range. Moreover, using the soft X-ray solar flux as a prior, we find that with a strong enough photon-chameleon coupling the chameleons emitted by the sun could lead to a regenerated photon flux in the CAST pipes, which could be within the reach...

  18. Solar chameleons

    International Nuclear Information System (INIS)

    Brax, Philippe; Zioutas, Konstantin

    2010-01-01

    We analyze the creation of chameleons deep inside the Sun (R∼0.7R sun ) and their subsequent conversion to photons near the magnetized surface of the Sun. We find that the spectrum of the regenerated photons lies in the soft x-ray region, hence addressing the solar corona problem. Moreover, these back-converted photons originating from chameleons have an intrinsic difference with regenerated photons from axions: their relative polarizations are mutually orthogonal before Compton interacting with the surrounding plasma. Depending on the photon-chameleon coupling and working in the strong coupling regime of the chameleons to matter, we find that the induced photon flux, when regenerated resonantly with the surrounding plasma, coincides with the solar flux within the soft x-ray energy range. Moreover, using the soft x-ray solar flux as a prior, we find that with a strong enough photon-chameleon coupling, the chameleons emitted by the Sun could lead to a regenerated photon flux in the CAST magnetic pipes, which could be within the reach of CAST with upgraded detector performance. Then, axion helioscopes have thus the potential to detect and identify particle candidates for the ubiquitous dark energy in the Universe.

  19. Solar flares

    International Nuclear Information System (INIS)

    Kaastra, J.S.

    1985-01-01

    In this thesis an electrodynamic model for solar flares is developed. The main theoretical achievements underlying the present study are treated briefly and the observable flare parameters are described within the framework of the flare model of this thesis. The flare model predicts large induced electric fields. Therefore, acceleration processes of charged particles by direct electric fields are treated. The spectrum of the accelerated particles in strong electric fields is calculated, 3 with the electric field and the magnetic field perpendicular and in the vicinity of an X-type magnetic neutral line. An electromagnetic field configuration arises in the case of a solar flare. A rising current filament in a quiescent background bipolar magnetic field causes naturally an X-type magnetic field configuration below the filament with a strong induced electric field perpendicular to the ambient magnetic field. This field configuration drives particles and magnetic energy towards the neutral line, where a current sheet is generated. The global evolution of the fields in the flare is determined by force balance of the Lorentz forces on the filament and the force balance on the current sheet. The X-ray, optical and radio observations of a large solar flare on May 16, 1981 are analyzed. It is found that these data fit the model very well. (Auth.)

  20. Solar neutrinos, helioseismology and the solar internal dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Turck-Chieze, Sylvaine [Service d' Astrophysique/IRFU/DSM/CEA, 91191 Gif sur Yvette Cedex (France); Couvidat, Sebastien, E-mail: sylvaine.turck-chieze@cea.fr, E-mail: couvidat@stanford.edu [HEPL, Stanford University, Stanford, CA 94305 (United States)

    2011-08-15

    Neutrinos are fundamental particles ubiquitous in the Universe and whose properties remain elusive despite more than 50 years of intense research activity. This review illustrates the importance of solar neutrinos in astrophysics, nuclear physics and particle physics. After a description of the historical context, we remind the reader of the noticeable properties of these particles and of the stakes of the solar neutrino puzzle. The standard solar model triggered persistent efforts in fundamental physics to predict the solar neutrino fluxes, and its constantly evolving predictions have been regularly compared with the detected neutrino signals. Anticipating that this standard model could not reproduce the internal solar dynamics, a seismic solar model was developed which enriched theoretical neutrino flux predictions with in situ observation of acoustic and gravity waves propagating in the Sun. This seismic model contributed to the stabilization of the neutrino flux predictions. This review recalls the main historical steps, from the pioneering Homestake mine experiment and the GALLEX-SAGE experiments capturing the first proton-proton neutrinos. It emphasizes the importance of the SuperKamiokande and SNO detectors. Both experiments demonstrated that the solar-emitted electron neutrinos are partially transformed into other neutrino flavors before reaching the Earth. This sustained experimental effort opens the door to neutrino astronomy, with long-base lines and underground detectors. The success of BOREXINO in detecting the {sup 7}Be neutrino signal alone instills confidence in physicists' ability to detect each neutrino source separately. It justifies the building of a new generation of detectors to measure the entire solar neutrino spectrum in greater detail, as well as supernova neutrinos. A coherent picture has emerged from neutrino physics and helioseismology. Today, new paradigms take shape in these two fields: neutrinos are massive particles, but their

  1. Thermal effects on cavity stability of chromium- and neodymium-doped gadolinium scandium gallium garnet laser under solar-simulator pumping

    Science.gov (United States)

    Kim, Kyong H.; Venable, Demetrius D.; Brown, Lamarr A.; Lee, Ja H.

    1991-01-01

    Results are presented on testing a Cr- and Nd-codoped Gd-Sc-Ga-garnet (Cr:Nd:GSGG) crystal and a Nd:YAG crystal (both of 3.2 mm diam and 76-mm long) for pulsed and CW laser operations using a flashlamp and solar simulator as pumping sources. Results from experiments with the flashlamp show that, at pulse lengths of 0.11, 0.28, and 0.90 ms, the slope efficiency of the Cd:Nd:GSGG crystal was higher than that of the Nd:YAG crystal and increased with pulse width. With the solar simulator, however, the CW laser operation of the Cr:Nd:GSGG crystal was limited to intensities not greater than 1500 solar constants, while the Nd:YAG laser successfully performed for all pump beam intensities available. It was found that the exposure for several minutes of the Cr:Nd:GSGG crystal to pump beam intensity of 3000 solar constants led to its damage by thermal cracking, indicating that a better solar-pumped CW laser performance may be difficult to realize with rod geometry.

  2. Elements of magnetohydrodynamic stability theory

    International Nuclear Information System (INIS)

    Spies, G.O.

    1976-11-01

    The nonlinear equations of ideal magnetohydrodynamics are discussed along with the following topics: (1) static equilibrium, (2) strict linear theory, (3) stability of a system with one degree of freedom, (4) spectrum and variational principles in magnetohydrodynamics, (5) elementary proof of the modified energy principle, (6) sufficient stability criteria, (7) local stability, and (8) normal modes

  3. Photochemical stability of conjugated polymers, electron acceptors and blends for polymer solar cells resolved in terms of film thickness and absorbance

    DEFF Research Database (Denmark)

    Tromholt, Thomas; Vesterager Madsen, Morten; Carlé, Jon Eggert

    2012-01-01

    Photochemical degradation at 1 sun under AM1.5G illumination was performed on six conjugated polymers and five different electron acceptors. Additionally, the respective polymer:PC60BM and P3HT:electron acceptor blends were studied, and all degradations were resolved in terms of film thickness...... within each material group were found to vary for both the pure polymers and the blends. The stability ranking between the materials of the pure polymers was found to be similar to the ranking for their respective blends, implying that the photochemical stability of a pure polymer is a good measure...... of its associated blend stability. Different electron acceptors were found to stabilize P3HT decreasingly with decreasing donor–acceptor LUMO–LUMO gap. Destabilization of P3HT was observed in the case of the electron acceptor ICBA. Additionally, the decreased stabilization of P3HT by high LUMO electron...

  4. Solar cell materials developing technologies

    CERN Document Server

    Conibeer, Gavin J

    2014-01-01

    This book presents a comparison of solar cell materials, including both new materials based on organics, nanostructures and novel inorganics and developments in more traditional photovoltaic materials. It surveys the materials and materials trends in the field including third generation solar cells (multiple energy level cells, thermal approaches and the modification of the solar spectrum) with an eye firmly on low costs, energy efficiency and the use of abundant non-toxic materials.

  5. Microstructure and thermal stability of Cu/Zr0.3Al0.7N/Zr0.2Al0.8N/Al34O60N6 cermet-based solar selective absorbing coatings

    Science.gov (United States)

    Meng, Jian-ping; Guo, Rui-rui; Li, Hu; Zhao, Lu-ming; Liu, Xiao-peng; Li, Zhou

    2018-05-01

    Solar selective absorbing coatings play a valuable role in photo-thermal conversion for high efficiency concentrating solar power systems (CSP). In this paper, a novel Cu/Zr0.3Al0.7N/Zr0.2Al0.8N/Al34O60N6 cermet-based solar selective absorbing coating was successfully deposited by ion beam assisted deposition. The optical properties, microstructure and element distribution in depth were investigated by spectroscopic ellipsometry, UV-vis-NIR spectrophotometer, transmission electron microscope (TEM) and Auger electron spectroscopy (AES), respectively. A high absorptance of 0.953 and a low thermal emittance of 0.079 at 400 °C are obtained by the integral computation according to the whole reflectance from 300 nm to 28,800 nm. After annealing treatment at 400 °C (in vacuum) for 192 h, the deposited coating exhibits the high thermal stability. Whereas, the photothermal conversion efficiency decreases from 12.10 to 6.86 due to the emittance increase after annealing at 600 °C for 192 h. Meanwhile, the nitrogen atom in the Zr0.3Al0.7N sub-layer diffuses toward the adjacent sub-layer due to the spinodal decomposition of metastable c-ZrAlN and the phase transition from c-AlN to h-AlN, which leads to the composition of the Zr0.3Al0.7N sub-layer deviates the initial design. This phenomenon has a guide effect for the thermal-stability improvement of cermet coatings. Additionally, a serious diffusion between copper and silicon substrate also contributes to the emittance increase.

  6. Zellweger Spectrum

    Science.gov (United States)

    ... severe defect, resulting in essentially nonfunctional peroxisomes. This phenomenon produces the range of severity of the disorders. How is the Zellweger Spectrum Diagnosed? The distinctive shape of the head and face of a child born with one of the diseases of the ...

  7. Flexible ITO-free organic solar cells applying aqueous solution-processed V2O5 hole transport layer: An outdoor stability study

    DEFF Research Database (Denmark)

    Lima, F. Anderson S.; Beliatis, Michail J.; Roth, Bérenger

    2016-01-01

    Solution processable semiconductor oxides have opened a new paradigm for theenhancement of the lifetime of thin film solar cells. Their fabrication by low-costand environmentally friendly solution-processable methods makes them ideal barrier(hole and electron) transport layers. In this work, we f...

  8. A Robust CuCr2O4/SiO2 Composite Photothermal Material with Underwater Black Property and Extremely High Thermal Stability for Solar-Driven Water Evaporation

    KAUST Repository

    Shi, Yusuf

    2017-12-27

    The design and fabrication of efficient photothermal materials is the key issue in solar-driven water evaporation. In this work, a robust CuCr2O4/SiO2 composite membrane with outstanding solar-driven water evaporation performance (1.32 kg m−2 h−1) under one sun irradiation is rationally designed and synthesized by using quartz glass fibrous membrane as supporting matrix and stable CuCr2O4 particles as the active light absorber. Instead of coating a separate layer on top of the support, the CuCr2O4 particles are evenly distributed inside the matrix, which endows the membrane with great mechanical strength and excellent wear and abrasion resistance. The highly porous composite survives 6 atm pressure and retains its performance even after 75% of the membrane is removed by sandpaper. This work also looks into a generally overlooked aspect of wet versus dry state of photothermal material and its implications. Interestingly, the composite possesses a gray color with a high reflectance in dry state but turns into deep black with a low reflectance in wet state due to the decreased subsurface scattering and strong NIR light absorbance of water in wet state. This composite material also possesses excellent thermal stability and thermal shock resistance, making it able to be easily recovered by calcination in air or direct burning in fire for contaminants removal. The results demonstrate that this composite is a competitive photothermal material for practical solar distillation and indicate that the optical properties of material in wet state are more relevant to photothermal material screening and optimization for solar distillation.

  9. Solar building

    OpenAIRE

    Zhang, Luxin

    2014-01-01

    In my thesis I describe the utilization of solar energy and solar energy with building integration. In introduction it is also mentioned how the solar building works, trying to make more people understand and accept the solar building. The thesis introduces different types of solar heat collectors. I compared the difference two operation modes of solar water heating system and created examples of solar water system selection. I also introduced other solar building applications. It is conv...

  10. Emerging Solar Technologies: Perovskite Solar Cell

    Indian Academy of Sciences (India)

    energy technologies and ... cost-effective and feasible non-silicon solar cell technologies. ..... storing in the air for long periods, and the stability reached up to .... [12] Y Liu, L A Renna, M Bag, Z A Page, P Kim, J Choi, T Emrick, D Venkatara-.

  11. Solar energy

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This chapter discusses the role solar energy may have in the energy future of the US. The topics discussed in the chapter include the solar resource, solar architecture including passive solar design and solar collectors, solar-thermal concentrating systems including parabolic troughs and dishes and central receivers, photovoltaic cells including photovoltaic systems for home use, and environmental, health and safety issues

  12. Improved photovoltaic performance and stability of quantum dot sensitized solar cells using Mn-ZnSe shell structure with enhanced light absorption and recombination control.

    Science.gov (United States)

    Gopi, Chandu V V M; Venkata-Haritha, M; Kim, Soo-Kyoung; Kim, Hee-Je

    2015-08-07

    To make quantum-dot-sensitized solar cells (QDSSCs) competitive, photovoltaic parameters comparable to those of other emerging solar cell technologies are necessary. In the present study, ZnSe was used as an alternative to ZnS, one of the most widely used passivation materials in QDSSCs. ZnSe was deposited on a TiO2-CdS-CdSe photoanode to form a core-shell structure, which was more efficient in terms of reducing the electron recombination in QDSSCs. The development of an efficient passivation layer is a requirement for preventing recombination processes in order to attain high-performance and stable QDSSCs. A layer of inorganic Mn-ZnSe was applied to a QD-sensitized photoanode to enhance the adsorption and strongly inhibit interfacial recombination processes in QDSSCs, which greatly improved the power conversion efficiency. Impedance spectroscopy revealed that the combined Mn doping with ZnSe treatment reduces interfacial recombination and increases charge collection efficiency compared with Mn-ZnS, ZnS, and ZnSe. A solar cell based on the CdS-CdSe-Mn-ZnSe photoanode yielded excellent performance with a solar power conversion efficiency of 5.67%, Voc of 0.584 V, and Jsc of 17.59 mA cm(-2). Enhanced electron transport and reduced electron recombination are responsible for the improved Jsc and Voc of the QDSSCs. The effective electron lifetime of the device with Mn-ZnSe was higher than those with Mn-ZnS, ZnSe, and ZnS, leading to more efficient electron-hole separation and slower electron recombination.

  13. Solar spectrum conversion for photovoltaics using nanoparticles

    NARCIS (Netherlands)

    Sark, W.G.J.H.M. van; Meijerink, A.; Schropp, R.E.I.

    2012-01-01

    The possibility to tune chemical and physical properties in nanosized materials has a strong impact on a variety of technologies, including photovoltaics. One of the prominent research areas of nanomaterials for photovoltaics involves spectral conversion. Conventional single-junction

  14. Feasibility of solar-pumped dye lasers

    Science.gov (United States)

    Lee, Ja H.; Kim, Kyung C.; Kim, Kyong H.

    1987-01-01

    Dye laser gains were measured at various pump-beam irradiances on a dye cell in order to evaluate the feasibility of solar pumping. Rhodamine 6G dye was considered as a candidate for the solar-pumped laser because of its high utilization of the solar spectrum and high quantum efficiency. Measurements show that a solar concentration of 20,000 is required to reach the threshold of the dye.

  15. Corrugation Architecture Enabled Ultraflexible Wafer-Scale High-Efficiency Monocrystalline Silicon Solar Cell

    KAUST Repository

    Bahabry, Rabab R.

    2018-01-02

    Advanced classes of modern application require new generation of versatile solar cells showcasing extreme mechanical resilience, large-scale, low cost, and excellent power conversion efficiency. Conventional crystalline silicon-based solar cells offer one of the most highly efficient power sources, but a key challenge remains to attain mechanical resilience while preserving electrical performance. A complementary metal oxide semiconductor-based integration strategy where corrugation architecture enables ultraflexible and low-cost solar cell modules from bulk monocrystalline large-scale (127 × 127 cm) silicon solar wafers with a 17% power conversion efficiency. This periodic corrugated array benefits from an interchangeable solar cell segmentation scheme which preserves the active silicon thickness of 240 μm and achieves flexibility via interdigitated back contacts. These cells can reversibly withstand high mechanical stress and can be deformed to zigzag and bifacial modules. These corrugation silicon-based solar cells offer ultraflexibility with high stability over 1000 bending cycles including convex and concave bending to broaden the application spectrum. Finally, the smallest bending radius of curvature lower than 140 μm of the back contacts is shown that carries the solar cells segments.

  16. Corrugation Architecture Enabled Ultraflexible Wafer-Scale High-Efficiency Monocrystalline Silicon Solar Cell

    KAUST Repository

    Bahabry, Rabab R.; Kutbee, Arwa T.; Khan, Sherjeel M.; Sepulveda, Adrian C.; Wicaksono, Irmandy; Nour, Maha A.; Wehbe, Nimer; Almislem, Amani Saleh Saad; Ghoneim, Mohamed T.; Sevilla, Galo T.; Syed, Ahad; Shaikh, Sohail F.; Hussain, Muhammad Mustafa

    2018-01-01

    Advanced classes of modern application require new generation of versatile solar cells showcasing extreme mechanical resilience, large-scale, low cost, and excellent power conversion efficiency. Conventional crystalline silicon-based solar cells offer one of the most highly efficient power sources, but a key challenge remains to attain mechanical resilience while preserving electrical performance. A complementary metal oxide semiconductor-based integration strategy where corrugation architecture enables ultraflexible and low-cost solar cell modules from bulk monocrystalline large-scale (127 × 127 cm) silicon solar wafers with a 17% power conversion efficiency. This periodic corrugated array benefits from an interchangeable solar cell segmentation scheme which preserves the active silicon thickness of 240 μm and achieves flexibility via interdigitated back contacts. These cells can reversibly withstand high mechanical stress and can be deformed to zigzag and bifacial modules. These corrugation silicon-based solar cells offer ultraflexibility with high stability over 1000 bending cycles including convex and concave bending to broaden the application spectrum. Finally, the smallest bending radius of curvature lower than 140 μm of the back contacts is shown that carries the solar cells segments.

  17. Over 2 Years of Outdoor Operational and Storage Stability of ITO-free, Fully Roll-to-Roll Fabricated Polymer Solar Cell Modules

    DEFF Research Database (Denmark)

    Angmo, Dechan; Krebs, Frederik C

    2015-01-01

    We report on the stability of large-area (100 cm2), low-cost, indium-tin-oxide (ITO)-free modules over two years (>17 500 h) under outdoor operational conditions in Denmark and under indoor storage condition by following ISOS-O-3 and ISOS-D-2 protocols. Irrespective of the testing regimes (storage...

  18. Desenvolvimento e avaliação da estabilidade física de loções O/A contendo filtros solares Development and evaluation of physical stability from O/ W lotions containing sunscreens

    Directory of Open Access Journals (Sweden)

    Greice Stefani Borghetti

    2006-12-01

    Full Text Available Os objetivos deste estudo foram desenvolver e avaliar a estabilidade física de loções do tipo O/A contendo 6% (p/p do filtro solar octilmetoxicinamato (OMC ou metilbenzilidenocânfora (MBC. As formulações foram armazenadas em temperatura ambiente durante seis meses e durante este período foram avaliadas com relação às suas características macroscópicas, viscosidade, comportamento reológico, índice de óleo, espalhabilidade e Fator de Proteção Solar (FPS. Os resultados demonstram que as formulações foram estáveis por seis meses. Os valores de FPS foram significativamente (P The objectives of this study were to develop and to evaluate the physical stability of O/W lotions containing 6% (w/w of the sunscreen octylmethoxycinnamate (OMC or methyl benzylidene camphor (MBC. The formulations were stored at room temperature, for six months and during this period its macroscopic characteristics, viscosity and rheological behavior, oil indexes, spreading properties and Sun Protection Factor (SPF were evaluated. The results demonstrate that both formulations were stable for six months. The SPF values were significantly (P < 0.05 higher for MBC formulation. On the other hand, the OMC formulation presented significantly (P < 0.05 higher spreading and lower viscosity values during the storage period.

  19. Solar gravitational redshift

    International Nuclear Information System (INIS)

    Lopresto, J.C.; Chapman, R.D.

    1980-01-01

    Wavelengths of solar spectrum lines should be shifted toward the red by the Sun's gravitational field as predicted by metric theories of gravity according to the principle of equivalence. Photographic wavelengths of 738 solar Fe 1 lines and their corresponding laboratory wavelengths have been studied. The measured solar wavelength minus the laboratory wavelength (Δlambdasub(observed)) averaged for the strong lines agrees well with the theoretically predicted shift (Δlambdasub(theoretical)). Studies show that the departures depend on line strength. No dependence of the departures on wavelength was found within the existing data. By studying strong lines over a wide spectral range, velocity shifts caused by the complex motions in the solar atmosphere seem to affect the results in a minimal fashion. (orig.)

  20. Air-processed organic tandem solar cells on glass: toward competitive operating lifetimes

    DEFF Research Database (Denmark)

    Adams, Jens; Spyropoulos, George D.; Salvador, Michael

    2015-01-01

    efficiencies of more than 10% the rather limited stability of this type of devices raises concerns towards future commercialization. The tandem concept allows for both absorbing a broader range of the solar spectrum and reducing thermalization losses. We designed an organic tandem solar cell with an inverted...... device geometry comprising environmentally stable active and charge-selecting layers. Under continuous white light irradiation, we demonstrate an extrapolated, operating lifetime in excess of one decade. We elucidate that for the current generation of organic tandem cells one critical requirement...... for long operating lifetimes consists of periodic UV light treatment. These results suggest that new material approaches towards UV-resilient active and interfacial layers may enable efficient organic tandem solar cells with lifetimes competitive with traditional inorganic photovoltaics....

  1. Research Progress on Preparation Technology and Stability of Perovskite Solar Cells%钙钛矿型太阳能电池制备工艺及稳定性研究进展

    Institute of Scientific and Technical Information of China (English)

    郭文明; 钟敏

    2017-01-01

    cell in this paper.Besides,the preparation process and various modification methods of electron transport layer were emphatically summarized.The electron transport layer plays a role in the transport of electrons and blocking holes in the structure of the perovskite solar cell.The energy level of electron transport layer can be controlled by doping technology to obtain better photoelectric conversion efficiency.The introduction of modification material on the electron transport layer can improve the morphology of the perovskite optical absorption layer,which can enhance the transmission and collection efficiency of the charge to improve the photoelectric conversion efficiency of the device.Afterwards,the synthesis optimization methods of the perovskite films were also discussed.The morphology and crystallinity of perovskite films can directly affect the optical trapping efficiency and short circuit current density.Therefore,high quality perovskite thin films were obtained by means of synthesis optimization,solvent engineering and annealing engineering.Moreover,we analyzed the reasons for the poor stability of perovskite solar cells,and then put forward the strategy to improve the stability of the solar cell.Finally,the commercial prospects of perovskite solar cells are forecasted.

  2. Spectrum 101: An Introduction to Spectrum Management

    Science.gov (United States)

    2004-03-01

    produces a Joint Restricted Frequency List (JRFL). The JFRL consolidates and classifies the spectrum uses that are most critical to operations and to...Management Office JRFL Joint Restricted Frequency List JSC Joint Spectrum Center JSIR Joint Spectrum Interference Resolution JSME Joint Spectrum...Multifunctional Information Distribution System MILSATCOM Military Satellite Communications MOA Memorandum of Agreement MRFL Master Radio Frequency

  3. Performance and stability of low-cost dye-sensitized solar cell based crude and pre-concentrated anthocyanins: Combined experimental and DFT/TDDFT study

    Science.gov (United States)

    Chaiamornnugool, Phrompak; Tontapha, Sarawut; Phatchana, Ratchanee; Ratchapolthavisin, Nattawat; Kanokmedhakul, Somdej; Sang-aroon, Wichien; Amornkitbamrung, Vittaya

    2017-01-01

    The low cost DSSCs utilized by crude and pre-concentrated anthocyanins extracted from six anthocyanin-rich samples including mangosteen pericarp, roselle, red cabbage, Thai berry, black rice and blue pea were fabricated. Their photo-to-current conversion efficiencies and stability were examined. Pre-concentrated extracts were obtained by solid phase extraction (SPE) using C18 cartridge. The results obviously showed that all pre-concentrated extracts performed on photovoltaic performances in DSSCs better than crude extracts except for mangosteen pericarp. The DSSC sensitized by pre-concentrated anthocyanin from roselle and red cabbage showed maximum current efficiency η = 0.71% while DSSC sensitized by crude anthocyanin from mangosteen pericarp reached maximum efficiency η = 0.97%. In addition, pre-concentrated extract based cells possess more stability than those of crude extract based cells. This indicates that pre-concentration of anthocyanin via SPE method is very effective for DSSCs based on good photovoltaic performance and stability. The DFT/TDDFT calculations of electronic and photoelectrochemical properties of the major anthocyanins found in the samples are employed to support the experimental results.

  4. Solar Features - Solar Flares

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A solar flare is a short-lived sudden increase in the intensity of radiation emitted in the neighborhood of sunspots. For many years it was best monitored in the...

  5. Solar storms; Tormentas solares

    Energy Technology Data Exchange (ETDEWEB)

    Collaboration: Pereira Cuesta, S.; Pereira Pagan, B.

    2016-08-01

    Solar storms begin with an explosion, or solar flare, on the surface of the sun. The X-rays and extreme ultraviolet radiation from the flare reach the Earths orbit minutes later-travelling at light speed. The ionization of upper layers of our atmosphere could cause radio blackouts and satellite navigation errors (GPS). Soon after, a wave of energetic particles, electrons and protons accelerated by the explosion crosses the orbit of the Earth, and can cause real and significant damage. (Author)

  6. Scalability and stability of very thin roll-to-roll processed large area indium-tin-oxide free polymer solar cell modules

    DEFF Research Database (Denmark)

    Angmo, Dechan; Gevorgyan, Suren; Larsen-Olsen, Thue Trofod

    2013-01-01

    Polymer solar cell modules were prepared directly on thin flexible barrier polyethylene terephthalate foil. The performance of the modules was found to be scalable from a single cell with an area of 6 cm2 to modules with a total area of up to 186 cm2. The substrate thickness was also explored...... employing P3HT:PCBM as the active material and were found to exhibit a total area efficiency of >1% (1000 W/m2; AM1.5G) with a typical active-area efficiency in the 1.5–1.6% for total module area of >110 cm2 due to high fill factors in excess of 50%. The modules were also found to have an active...

  7. Enhanced solar cell efficiency and stability using ZnS passivation layer for CdS quantum-dot sensitized actinomorphic hexagonal columnar ZnO

    International Nuclear Information System (INIS)

    Chen, Yanli; Tao, Qiang; Fu, Wuyou; Yang, Haibin; Zhou, Xiaoming; Zhang, Yanyan; Su, Shi; Wang, Peng; Li, Minghui

    2014-01-01

    Highlights: • The synthetic of ZnS/CdS QDs/AHC-ZnO photoanode with a simple method. • The power conversion efficiency of the ZnS/CdS QDs/AHC-ZnO is 1.81%. • The effects of photovoltaic performances caused by CdS and ZnS amounts were studied. • ZnS passivation layer enhanced electron lifetime significantly. - Abstract: We report the photoanodes consisting of CdS quantum-dots (QDs) sensitized actinomorphic hexagonal columnar ZnO (CdS QDs/AHC-ZnO) with ZnS passivation layer are applied for solar cells. Simple chemical solution synthesized AHC-ZnO films on transparent conducting glass substrates, and then, AHC-ZnO is functionalized with uniform CdS and ZnS QDs via successive ionic layer adsorption and reaction (SILAR) method. The as-prepared materials were characterized by XRD, SEM, TEM, UV–vis diffused reflectance absorption spectra and photovoltaic performances analysis. Photovoltaic performances results indicate the quantity of CdS QDs as well as the visible light absorption threshold can be effectively controlled by varying the coating cycles during the SILAR process, and the photocurrent density (Jsc) is greatly improved by increasing the amount of ZnS. By optimizing the AHC-ZnO with the amount of CdS and ZnS, the best efficiency of 1.81% was achieved for solar cell under AM 1.5 G illumination with Jsc = 7.44 mA/cm 2 , Voc = 0.57 V and FF = 43%

  8. Solar noise storms

    CERN Document Server

    Elgaroy, E O

    2013-01-01

    Solar Noise Storms examines the properties and features of solar noise storm phenomenon. The book also presents some theories that can be used to gain a better understanding of the phenomenon. The coverage of the text includes topics that cover the features and behavior of noise storms, such as the observable features of noise storms; the relationship between noise storms and the observable features on the sun; and ordered behavior of storm bursts in the time-frequency plane. The book also covers the spectrum, polarization, and directivity of noise storms. The text will be of great use to astr

  9. Spectral mismatch and solar simulator quality factor in advanced LED solar simulators

    Science.gov (United States)

    Scherff, Maximilian L. D.; Nutter, Jason; Fuss-Kailuweit, Peter; Suthues, Jörn; Brammer, Torsten

    2017-08-01

    Solar cell simulators based on light emitting diodes (LED) have the potential to achieve a large potential market share in the next years. As advantages they can provide a short and long time stable spectrum, which fits very well to the global AM1.5g reference spectrum. This guarantees correct measurements during the flashes and throughout the light engines’ life span, respectively. Furthermore, a calibration with a solar cell type of different spectral response (SR) as well as the production of solar cells with varying SR in between two calibrations does not affect the correctness of the measurement result. A high quality 21 channel LED solar cell spectrum is compared to former study comprising a standard modified xenon spectrum light source. It is shown, that the spectrum of the 21-channel-LED light source performs best for all examined cases.

  10. MSW effect and solar neutrino experiments

    International Nuclear Information System (INIS)

    Rosen, S.P.

    1986-01-01

    We describe the MSW solutions to the 37 Cl solar neutrino experiment, and their implications for the 71 Ga experiment. Measurement of the spectrum of electron-type neutrinos arriving at earth is emphasized. 8 refs., 2 figs., 1 tab

  11. Diketopyrrolopyrrole polymers for organic solar cells

    NARCIS (Netherlands)

    Li, Wei Wei; Hendriks, K.H.; Wienk, M.M.; Janssen, R.A.J.

    2016-01-01

    Conspectus Conjugated polymers have been extensively studied for application in organic solar cells. In designing new polymers, particular attention has been given to tuning the absorption spectrum, molecular energy levels, crystallinity, and charge carrier mobility to enhance performance. As a

  12. Rotational spectrum of tryptophan

    Energy Technology Data Exchange (ETDEWEB)

    Sanz, M. Eugenia, E-mail: maria.sanz@kcl.ac.uk; Cabezas, Carlos, E-mail: ccabezas@qf.uva.es; Mata, Santiago, E-mail: santiago.mata@uva.es; Alonso, Josè L., E-mail: jlalonso@qf.uva.es [Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Laboratorios de Espectroscopia y Bioespectroscopia, Unidad Asociada CSIC, Parque Científico Uva, Universidad de Valladolid, 47011 Valladolid (Spain)

    2014-05-28

    The rotational spectrum of the natural amino acid tryptophan has been observed for the first time using a combination of laser ablation, molecular beams, and Fourier transform microwave spectroscopy. Independent analysis of the rotational spectra of individual conformers has conducted to a definitive identification of two different conformers of tryptophan, with one of the observed conformers never reported before. The analysis of the {sup 14}N nuclear quadrupole coupling constants is of particular significance since it allows discrimination between structures, thus providing structural information on the orientation of the amino group. Both observed conformers are stabilized by an O–H···N hydrogen bond in the side chain and a N–H···π interaction forming a chain that reinforce the strength of hydrogen bonds through cooperative effects.

  13. Stability and controllability of InGaAs/GaAsP wire-on-well (WoW) structure for multi-junction solar cells

    Science.gov (United States)

    Cho, Hirofumi; Toprasertpong, Kasidit; Sodabanlu, Hassanet; Watanabe, Kentaroh; Sugiyama, Masakazu; Nakano, Yoshiaki

    2017-04-01

    Wire on Well (WoW) structure embedded in a matrix is naturally formed by growing InxGa1-xAs/GaAs1-yPy strained multiple quantum wells (MQW) on vicinal substrates and employing triethylgallium (TEGa) as a precursor in low-temperature MOVPE. The structure is useful for the subcell in current-matched mult-junction solar cells with lattice-matched materials because of its ability of band-gap tuning. In this research, high density and uniform In0.30Ga0.70As/GaAs0.6P0.4 WoW was obtained up to 200 stacks and its structure was analyzed by X-ray diffraction reciprocal space mapping, atomic force microscopy and scanning transmission electron microscopy. The structure of the wire can be controlled by changing the equivalent layer thicknesses of In0.30Ga0.70As and GaAs0.6P0.4. The photoluminescence peak from the WoW shifted according to the size of InGaAs wires and the intensity was dependent on the accumulation of lattice-mismatch stress.

  14. An Unfused-Core-Based Nonfullerene Acceptor Enables High-Efficiency Organic Solar Cells with Excellent Morphological Stability at High Temperatures.

    Science.gov (United States)

    Li, Shuixing; Zhan, Lingling; Liu, Feng; Ren, Jie; Shi, Minmin; Li, Chang-Zhi; Russell, Thomas P; Chen, Hongzheng

    2018-02-01

    Most nonfullerene acceptors developed so far for high-performance organic solar cells (OSCs) are designed in planar molecular geometry containing a fused-ring core. In this work, a new nonfullerene acceptor of DF-PCIC is synthesized with an unfused-ring core containing two cyclopentadithiophene (CPDT) moieties and one 2,5-difluorobenzene (DFB) group. A nearly planar geometry is realized through the F···H noncovalent interaction between CPDT and DFB for DF-PCIC. After proper optimizations, the OSCs with DF-PCIC as the acceptor and the polymer PBDB-T as the donor yield the best power conversion efficiency (PCE) of 10.14% with a high fill factor of 0.72. To the best of our knowledge, this efficiency is among the highest values for the OSCs with nonfullerene acceptors owning unfused-ring cores. Furthermore, no obvious morphological changes are observed for the thermally treated PBDB-T:DF-PCIC blended films, and the relevant devices can keep ≈70% of the original PCEs upon thermal treatment at 180 °C for 12 h. This tolerance of such a high temperature for so long time is rarely reported for fullerene-free OSCs, which might be due to the unique unfused-ring core of DF-PCIC. Therefore, the work provides new idea for the design of new nonfullerene acceptors applicable in commercial OSCs in the future. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Realizing InGaN monolithic solar-photoelectrochemical cells for artificial photosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Dahal, R.; Pantha, B. N.; Li, J.; Lin, J. Y.; Jiang, H. X., E-mail: hx.jiang@ttu.edu [Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, Texas 79409 (United States)

    2014-04-07

    InGaN alloys are very promising for solar water splitting because they have direct bandgaps that cover almost the whole solar spectrum. The demonstration of direct solar-to-fuel conversion without external bias with the sunlight being the only energy input would pave the way for realizing photoelectrochemical (PEC) production of hydrogen by using InGaN. A monolithic solar-PEC cell based on InGaN/GaN multiple quantum wells capable to directly generate hydrogen gas under zero bias via solar water splitting is reported. Under the irradiation by a simulated sunlight (1-sun with 100 mW/cm{sup 2}), a 1.5% solar-to-fuel conversion efficiency has been achieved under zero bias, setting a fresh benchmark of employing III-nitrides for artificial photosynthesis. Time dependent hydrogen gas production photocurrent measured over a prolonged period (measured for 7 days) revealed an excellent chemical stability of InGaN in aqueous solution of hydrobromic acid. The results provide insights into the architecture design of using InGaN for artificial photosynthesis to provide usable clean fuel (hydrogen gas) with the sunlight being the only energy input.

  16. Solar Energy.

    Science.gov (United States)

    Eaton, William W.

    Presented is the utilization of solar radiation as an energy resource principally for the production of electricity. Included are discussions of solar thermal conversion, photovoltic conversion, wind energy, and energy from ocean temperature differences. Future solar energy plans, the role of solar energy in plant and fossil fuel production, and…

  17. Solar energy

    Science.gov (United States)

    Rapp, D.

    1981-01-01

    The book opens with a review of the patterns of energy use and resources in the United States, and an exploration of the potential of solar energy to supply some of this energy in the future. This is followed by background material on solar geometry, solar intensities, flat plate collectors, and economics. Detailed attention is then given to a variety of solar units and systems, including domestic hot water systems, space heating systems, solar-assisted heat pumps, intermediate temperature collectors, space heating/cooling systems, concentrating collectors for high temperatures, storage systems, and solar total energy systems. Finally, rights to solar access are discussed.

  18. Solar Combisystems

    DEFF Research Database (Denmark)

    Thür, Alexander

    2006-01-01

    This note first introduces what is a solar combisystem, the structure how a solar combisystem is build up and what are criteria’s to evaluate a solar combisystem concept. Further on the main components of a solar combisystem, the main characteristics and possible advantages and disadvantages...... compared to each other are described. It is not the goal of this note to explain the technical details how to design all components of a solar combisystem. This is done during other lectures of the solar course and in other basic courses as well. This note tries to explain how a solar combisystem...

  19. Solar Systems

    Science.gov (United States)

    1979-01-01

    The solar collectors shown are elements of domestic solar hot water systems produced by Solar One Ltd., Virginia Beach, Virginia. Design of these systems benefited from technical expertise provided Solar One by NASA's Langley Research Center. The company obtained a NASA technical support package describing the d e sign and operation of solar heating equipment in NASA's Tech House, a demonstration project in which aerospace and commercial building technology are combined in an energy- efficient home. Solar One received further assistance through personal contact with Langley solar experts. The company reports that the technical information provided by NASA influenced Solar One's panel design, its selection of a long-life panel coating which increases solar collection efficiency, and the method adopted for protecting solar collectors from freezing conditions.

  20. Interfacial Engineering of Perovskite Solar Cells by Employing a Hydrophobic Copper Phthalocyanine Derivative as Hole-Transporting Material with Improved Performance and Stability.

    Science.gov (United States)

    Jiang, Xiaoqing; Yu, Ze; Lai, Jianbo; Zhang, Yuchen; Hu, Maowei; Lei, Ning; Wang, Dongping; Yang, Xichuan; Sun, Licheng

    2017-04-22

    In high-performance perovskite solar cells (PSCs), hole-transporting materials (HTMs) play an important role in extracting and transporting the photo-generated holes from the perovskite absorber to the cathode, thus reducing unwanted recombination losses and enhancing the photovoltaic performance. Herein, solution-processable tetra-4-(bis(4-tert-butylphenyl)amino)phenoxy-substituted copper phthalocyanine (CuPc-OTPAtBu) was synthesized and explored as a HTM in PSCs. The optical, electrochemical, and thermal properties were fully characterized for this organic metal complex. The photovoltaic performance of PSCs employing this CuPc derivative as a HTM was further investigated, in combination with a mixed-ion perovskite as a light absorber and a low-cost vacuum-free carbon as cathode. The optimized devices [doped with 6 % (w/w) tetrafluoro-tetracyano-quinodimethane (F4TCNQ)] showed a decent power conversion efficiency of 15.0 %, with an open-circuit voltage of 1.01 V, a short-circuit current density of 21.9 mA cm -2 , and a fill factor of 0.68. Notably, the PSC devices studied also exhibited excellent long-term durability under ambient condition for 720 h, mainly owing to the introduction of the hydrophobic HTM interlayer, which prevents moisture penetration into the perovskite film. The present work emphasizes that solution-processable CuPc holds a great promise as a class of alternative HTMs that can be further explored for efficient and stable PSCs in the future. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Solarização do solo com filmes plásticos com e sem aditivo estabilizador de luz ultravioleta Soil solarization with plastic films with and without UV light stabilizers

    Directory of Open Access Journals (Sweden)

    Benedito C. Barros

    2004-06-01

    menor nos tratamentos com plástico contendo aditivo. A viabilidade de P. aphanidermatum foi reduzida em todos os tratamentos solarizados, independente do plástico utilizado. Houve aumento no pH, na saturação por bases (V% e nos teores de NH4+ (190%, Mn (94,6% e Mg2+ (18%, dos solos solarizados. Também as plantas de alface colhidas nessas parcelas apresentaram maiores teores de Zn (43%, Mg2+ (12% e K+ (4%. Em Mogi das Cruzes foram observados aumentos nos teores de Mn (236% e Cu (18% nos solos solarizados e nas plantas colhidas nesses tratamentos (aumento de 99% para Mn e de 27% para Cu. A incidência da podridão de esclerotínia foi reduzida de 27,7% na testemunha para índices inferiores a 1% nas parcelas solarizadas com os diferentes filmes plásticos. O plástico sem aditivo estabilizador de luz ultravioleta partiu-se durante ambos os experimentos, após 60 e 90 dias de exposição ao ambiente, sendo considerado inadequado para a solarização, mas não houve diferença entre os plásticos para nenhum atributo avaliado.Three plastic films [low-density polyethylene (LDPE plastic films, 100 mm thick, produced by Nortène Plásticos Ltda] were evaluated in their adequacy for soil solarization:. a LDPE with UV light stabilizer additive, based on hindered amine; b LDPE with half load of the same additive, c without additive, and d a control treatment without plastic mulch. Two experiments were set up from January to February 2000, in Mogi das Cruzes and Piracicaba, São Paulo State, Brazil. After solarization, a lettuce crop was grown in both experiments. Chemical analyses were performed in soil samples and in the harvested lettuce heads of all plots. Weed infestation and the fresh weight of the harvested lettuce heads were assessed. In Piracicaba the soils were analyzed for microbiological properties and the viability of Pythium aphanidermatum was evaluated. In Mogi das Cruzes incidence of lettuce drop, caused by Sclerotinia minor, was assessed. The mean soil

  2. Solar radiophysics

    International Nuclear Information System (INIS)

    McLean, D.J.; Labrum, N.R.

    1985-01-01

    This book treats all aspects of solar radioastronomy at metre wavelengths, particularly work carried out on the Australian radioheliograph at Culgoora, with which most of the authors have been associated in one way or another. After an introductory section on historical aspects, the solar atmosphere, solar flares, and coronal radio emission, the book deals with instrumentation, theory, and details of observations and interpretations of the various aspects of metrewave solar radioastronomy, including burst types, solar storms, and the quiet sun. (U.K.)

  3. Solar neutrino detection

    International Nuclear Information System (INIS)

    Miramonti, Lino

    2009-01-01

    More than 40 years ago, neutrinos where conceived as a way to test the validity of the solar models which tell us that stars are powered by nuclear fusion reactions. The first measurement of the neutrino flux, in 1968 in the Homestake mine in South Dakota, detected only one third of the expected value, originating what has been known as the Solar Neutrino Problem. Different experiments were built in order to understand the origin of this discrepancy. Now we know that neutrinos undergo oscillation phenomenon changing their nature traveling from the core of the Sun to our detectors. In the work the 40 year long saga of the neutrino detection is presented; from the first proposals to test the solar models to last real time measurements of the low energy part of the neutrino spectrum.

  4. Solar Magnetic Atmospheric Effects on Global Helioseismic ...

    Indian Academy of Sciences (India)

    provide priceless diagnostic tools in the search for hidden aspects of the solar interior ... The overall structure of the helioseismic frequency spectrum, see Figure 1, has not .... 10.7 cm radio flux were used as a proxy of the solar surface activity. All the ..... According to their predictions, at least B = 5 × 105 G field strength is.

  5. New and precise construction of the local interstellar electron spectrum from the radio background and an application to the solar modulation of cosmic rays showing an incompatability of the electron and nuclei modulation using the spherically symmetric Fokker-Planck equation

    International Nuclear Information System (INIS)

    Rockstroh, J.M.

    1977-01-01

    Cosmic-ray electrons generate the observed radio-frequency background. Previous attempts in the literature to reconcile quantitatively the measured radio-frequency intensity with the intensity deduced from the electron spectrum measured at earth have culminated in the problem that to get the respective emissivities to agree, an unacceptably high interstellar B field must be chosen. In the light of new experimental data on the emissivity as deduced from H II region studies and on the functional dependence of the diffusion coefficient with solar radius and particle rigidity, the assumptions under which the electron emissivity comparison has been made have been reexamined closely. The paradox between predicted and measured emissivity was resolved by ascribing to the magnetic fields of the galaxy a distribution of magnetic field strengths. From modified synchrotron formulas, the interstellar electron spectrum has been constructed from the radio frequency emission data with greatly improved precision. The interstellar electron spectrum has been determined independently of the solar modulation and provides, therefore, an estimate of the absolute depth of the electron modulation. Then the measured electron, proton, and helium-nuclei fluxes were systematically compared to the predictions of the spherically symmetric Fokker-Planck equation using the electron modulation as a base. A previously unnoticed non-tracking of the modulation parameters was observed during the recent recovery that did not occur during the 1965 to 1969 period. Although the argument could be presented just as well by attributing the anomaly to the nuclei, the discussion here arbitrarily tailored it to the electrons, and this new phenomenon was named, the modulation reluctance of the cosmic-ray electrons

  6. Enhancement of Power Efficiency and Stability of P3HT-Based Organic Solar Cells under Elevated Operating-Temperatures by Using a Nanocomposite Photoactive Layer

    Directory of Open Access Journals (Sweden)

    Tran Thi Thao

    2015-01-01

    Full Text Available With the aim to find out an enhanced operating-temperature range for photovoltaic device parameters, two types of the photoactive layer were prepared: poly(3-hexylthiophene (P3HT and P3HT+nc-TiO2 (PTC thin films. The enhancement obtained for the photoelectrical conversion efficiency of the composite based OSCs is attributed to the presence of nanoheterojunctions of TiO2/P3HT. For the temperature range of 30–70°C, the decrease of the open-circuit potential was compensated by an increase of the fill factor; and the increase in the short-circuit current resulted in an overall increase of the energy conversion efficiency. At elevated temperatures of 60–80°C the efficiency of the P3HT- and PTC-based cells reached a maximum value of 1.6% and 2.1%, respectively. Over this temperature range the efficiency of P3HT-based OSC decreased strongly to zero, whereas for the PTC cells it maintained a value as large as 1.2% at the temperature range of 110–140°C. The improved thermal stability of the composite-based device was attributed to the lowered thermal expansion coefficient of the nanocomposite photoactive layer.

  7. Spectrum estimation method based on marginal spectrum

    International Nuclear Information System (INIS)

    Cai Jianhua; Hu Weiwen; Wang Xianchun

    2011-01-01

    FFT method can not meet the basic requirements of power spectrum for non-stationary signal and short signal. A new spectrum estimation method based on marginal spectrum from Hilbert-Huang transform (HHT) was proposed. The procession of obtaining marginal spectrum in HHT method was given and the linear property of marginal spectrum was demonstrated. Compared with the FFT method, the physical meaning and the frequency resolution of marginal spectrum were further analyzed. Then the Hilbert spectrum estimation algorithm was discussed in detail, and the simulation results were given at last. The theory and simulation shows that under the condition of short data signal and non-stationary signal, the frequency resolution and estimation precision of HHT method is better than that of FFT method. (authors)

  8. Photon management in solar cells

    CERN Document Server

    Rau, Uwe; Gombert, Andreas

    2015-01-01

    Written by renowned experts in the field of photon management in solar cells, this one-stop reference gives an introduction to the physics of light management in solar cells, and discusses the different concepts and methods of applying photon management. The authors cover the physics, principles, concepts, technologies, and methods used, explaining how to increase the efficiency of solar cells by splitting or modifying the solar spectrum before they absorb the sunlight. In so doing, they present novel concepts and materials allowing for the cheaper, more flexible manufacture of solar cells and systems. For educational purposes, the authors have split the reasons for photon management into spatial and spectral light management. Bridging the gap between the photonics and the photovoltaics communities, this is an invaluable reference for materials scientists, physicists in industry, experimental physicists, lecturers in physics, Ph.D. students in physics and material sciences, engineers in power technology, appl...

  9. Solar opacities constrained by solar neutrinos and solar oscillations

    International Nuclear Information System (INIS)

    Cox, A.N.

    1989-01-01

    This review discusses the current situation for opacities at the solar center, the solar surface, and for the few million kelvin temperatures that occur below the convection zone. The solar center conditions are important because they are crucial for the neutrino production, which continues to be predicted about 4 times that observed. The main extinction effects there are free-free photon absorption in the electric fields of the hydrogen, helium and the CNO atoms, free electron scattering of photons, and the bound-free and bound-bound absorption of photons by iron atoms with two electrons in the 1s bound level. An assumption that the iron is condensed-out below the convection zone, and the opacity in the central regions is thereby reduced, results in about a 25 percent reduction in the central opacity but only a 5 percent reduction at the base of the convection zone. Furthermore, the p-mode solar oscillations are changed with this assumption, and do not fit the observed ones as well as for standard models. A discussion of the large effective opacity reduction by weakly interacting massive particles also results in poor agreement with observed p-mode oscillation frequencies. The much larger opacities for the solar surface layers from the Los Alamos Astrophysical Opacity Library instead of the widely used Cox and Tabor values show small improvements in oscillation frequency predictions, but the largest effect is in the discussion of p-mode stability. Solar oscillation frequencies can serve as an opacity experiment for the temperatures and densities, respectively, of a few million kelvin and between 0.1 and 10 g/cm 3 . Current oscillation frequency calculations indicate that possibly the Opacity Library values need an increase of typically 15 percent just at the bottom of the convection zone at 3 x 10 6 K. 41 refs., 15 figs., 1 tab

  10. Turbulence and Solar p-Mode Oscillations

    Science.gov (United States)

    Bi, S. L.; Xu, H. Y.

    The discrepancy between observed and theoretical mode frequencies can be used to examine the reliability of the standard solar model as a faithful representation of solar real situation. With the help of an improved time-dependent convective model that takes into account contribution of the full spatial and temporal turbulent energy spectrum, we study the influence of turbulent pressure on structure and solar p-mode frequencies. For the radial modes we find that the Reynolds stress produces signification modifications in structure and p-mode spectrum. Compared with an adiabatic approximation, the discrepancy is largely removed by the turbulent correction.

  11. Solar energy

    International Nuclear Information System (INIS)

    Kruisheer, N.

    1992-01-01

    In five brief articles product information is given on solar energy applications with special attention to the Netherlands. After an introduction on solar energy availability in the Netherlands the developments in solar boiler techniques are dealt with. Solar water heaters have advantages for the environment, and government subsidies stimulate different uses of such water heaters. Also the developments of solar cells show good prospects, not only for developing countries, but also for the industrialized countries. In brief the developments in solar energy storage and the connection of solar equipment to the grid are discussed. Finally attention is paid to the applications of passive solar energy in the housing construction, the use of transparent thermal insulation and the developments of translucent materials. 18 figs., 18 ills

  12. Solar Imagery

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of solar photographic and illustrated datasets contributed by a number of national and private solar observatories located worldwide....

  13. Solar Features

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of solar feature datasets contributed by a number of national and private solar observatories located worldwide.

  14. Solar Indices

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  15. Solar Special

    International Nuclear Information System (INIS)

    Van Roekel, A.; Osborne, J.; Schroeter, S.; De Jong, R.; De Saint Jacob, Y.

    2009-01-01

    Solar power is growing much faster than most policymakers and analysts realise. As costs come down and feed-in tariffs go up across Europe, a number of countries have started in pursuit of market leader Germany. But in Germany criticism is growing of the multi-billion-euro support schemes that keep the solar industry booming. In this section of the magazine several articles are dedicated to developments in solar energy in Europe. The first article is an overview story on the strong growing global market for solar cells, mainly thanks to subsidy schemes. The second article is on the position of foreign companies in the solar market in Italy. Article number three is dedicated to the conditions for solar technology companies to establish themselves in the German state of Saxony. Also the fifth article deals with the development of solar cells in Saxony: scientists, plant manufacturers and module producers in Saxony are working on new technologies that can be used to produce solar electricity cost-effectively. The goal is to bring the price down to match that of conventionally generated electricity within the next few years. The sixth article deals with the the solar power market in Belgium, which may be overheated or 'oversubsidized'. Article seven is on France, which used to be a pioneer in solar technology, but now produces only a fraction of the solar output of market leader Germany. However, new attractive feed-in-tariffs are changing the solar landscape drastically

  16. Solar cell power source system

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Yoichi; Toma, Kunio; Fukuwa, Shinji

    1988-05-14

    This invention aims to supply a power source system with stable power output by reducing the power loss due to switching in the voltage stabilization even when the power source is a solar cell with frequent voltage variation. For this purpose, in a solar cell power source system consisting of a solar cell, a storage battery, a switching regulator placed between the storage cell and the load, and a load, arrangement was made that, by judging the input voltage from the storage battery, switch-acting the transistor of the switching regulator, if the input voltage is higher than the specified voltage; is the input voltage is lower than the specified voltage, the transistor is put in a full-on state. By this, the supply voltage can be stabilized even when the voltage fluctuates, and system gets more efficient as the switching loss decreases in the voltage stabilizing means. (1 fig)

  17. A rapid method of estimating the solar irradiance spectra with potential lighting applications

    NARCIS (Netherlands)

    Gao, Y.; Dong, J.; Isabella, O.; Zeman, M.; Zhang, G

    2016-01-01

    Diverse solar irradiance spectra can be observed under different conditions of time, date, location, weather, etc. Since the solar irradiance spectrum is required by certain scientific and engineering applications, obtaining accurate spectral data is essential. Measurements by spectrophotometers are

  18. A panchromatic anthracene-fused porphyrin sensitizer for dye-sensitized solar cells

    KAUST Repository

    Ball, James M.; Davis, Nicola K. S.; Wilkinson, James D.; Kirkpatrick, James; Teuscher, Joë l; Gunning, Robert; Anderson, Harry L.; Snaith, Henry J.

    2012-01-01

    The development of ruthenium-free sensitizers which absorb light over a broad range of the solar spectrum is important for improving the power conversion efficiency of dye-sensitized solar cells. Here we study three chemically tailored porphyrin

  19. Maximizing tandem solar cell power extraction using a three-terminal design

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Emily L. [National Renewable Energy Lab; USA; Deceglie, Michael G. [National Renewable Energy Lab; USA; Rienäcker, Michael [Institute for Solar Energy Research Hamelin; Germany; Peibst, Robby [Institute for Solar Energy Research Hamelin; Germany; Tamboli, Adele C. [National Renewable Energy Lab; USA; Stradins, Paul [National Renewable Energy Lab; USA

    2018-01-01

    Three-terminal tandem solar cells can provide a robust operating mechanism to efficiently capture the solar spectrum without the need to current match sub-cells or fabricate complicated metal interconnects.

  20. Solar Indices - Solar Radio Flux

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  1. Solar Coronal Jets: Observations, Theory, and Modeling

    Science.gov (United States)

    Raouafi, N. E.; Patsourakos, S.; Pariat, E.; Young, P. R.; Sterling, A.; Savcheva, A.; Shimojo, M.; Moreno-Insertis, F.; Devore, C. R.; Archontis, V.; hide

    2016-01-01

    Chromospheric and coronal jets represent important manifestations of ubiquitous solar transients, which may be the source of signicant mass and energy input to the upper solar atmosphere and the solar wind. While the energy involved in a jet-like event is smaller than that of nominal solar ares and Coronal Mass Ejections (CMEs), jets share many common properties with these major phenomena, in particular, the explosive magnetically driven dynamics. Studies of jets could, therefore, provide critical insight for understanding the larger, more complex drivers of the solar activity. On the other side of the size-spectrum, the study of jets could also supply important clues on the physics of transients closeor at the limit of the current spatial resolution such as spicules. Furthermore, jet phenomena may hint to basic process for heating the corona and accelerating the solar wind; consequently their study gives us the opportunity to attack a broadrange of solar-heliospheric problems.

  2. Coupled solar still, solar heater

    Energy Technology Data Exchange (ETDEWEB)

    Davison, R R; Harris, W B; Moor, D H; Delyannis, A; Delyannis, E [eds.

    1976-01-01

    Computer simulation of combinations of solar stills and solar heaters indicates the probable economic advantage of such an arrangement in many locations if the size of the heater is optimized relative to that of the still. Experience with various low cost solar heaters is discussed.

  3. Solar Sailing

    Science.gov (United States)

    Johnson, Les

    2009-01-01

    Solar sailing is a topic of growing technical and popular interest. Solar sail propulsion will make space exploration more affordable and offer access to destinations within (and beyond) the solar system that are currently beyond our technical reach. The lecture will describe solar sails, how they work, and what they will be used for in the exploration of space. It will include a discussion of current plans for solar sails and how advanced technology, such as nanotechnology, might enhance their performance. Much has been accomplished recently to make solar sail technology very close to becoming an engineering reality and it will soon be used by the world s space agencies in the exploration of the solar system and beyond. The first part of the lecture will summarize state-of-the-art space propulsion systems and technologies. Though these other technologies are the key to any deep space exploration by humans, robots, or both, solar-sail propulsion will make space exploration more affordable and offer access to distant and difficult destinations. The second part of the lecture will describe the fundamentals of space solar sail propulsion and will describe the near-, mid- and far-term missions that might use solar sails as a propulsion system. The third part of the lecture will describe solar sail technology and the construction of current and future sailcraft, including the work of both government and private space organizations.

  4. Optical and Structural Characterization of Nickel Coatings for Solar Collector Receivers

    OpenAIRE

    Pratesi, S.; Sani, E.; De Lucia, M.

    2014-01-01

    The development of spectrally selective materials is gaining an increasing role in solar thermal technology. The ideal spectrally selective solar absorber requires high absorbance at the solar spectrum wavelengths and low emittance at the wavelengths of thermal spectrum. Selective coating represents a promising route to improve the receiver efficiency for parabolic trough collectors (PTCs). In this work, we describe an intermediate step in the fabrication of black-chrome based solar absorbers...

  5. An Experimentalist's Overview of Solar Neutrinos

    Science.gov (United States)

    Oser, Scott M.

    2012-02-01

    Four decades of solar neutrino research have demonstrated that solar models do a remarkable job of predicting the neutrino fluxes from the Sun, to the extent that solar neutrinos can now serve as a calibrated neutrino source for experiments to understand neutrino oscillations and mixing. In this review article I will highlight the most significant experimental results, with emphasis on the latest model-independent measurements from the Sudbury Neutrino Observatory. The solar neutrino fluxes are seen to be generally well-determined experimentally, with no indications of time variability, while future experiments will elucidate the lower energy part of the neutrino spectrum, especially pep and CNO neutrinos.

  6. An Experimentalist's Overview of Solar Neutrinos

    International Nuclear Information System (INIS)

    Oser, Scott M

    2012-01-01

    Four decades of solar neutrino research have demonstrated that solar models do a remarkable job of predicting the neutrino fluxes from the Sun, to the extent that solar neutrinos can now serve as a calibrated neutrino source for experiments to understand neutrino oscillations and mixing. In this review article I will highlight the most significant experimental results, with emphasis on the latest model-independent measurements from the Sudbury Neutrino Observatory. The solar neutrino fluxes are seen to be generally well-determined experimentally, with no indications of time variability, while future experiments will elucidate the lower energy part of the neutrino spectrum, especially pep and CNO neutrinos.

  7. Dynamic Spectrum Sharing among Femtocells

    DEFF Research Database (Denmark)

    Da Costa, Gustavo Wagner Oliveira

    2012-01-01

    deployment of femtocells in an uncoordinated way will create difficult interference scenarios. For these reasons, this PhD thesis investigates how each femtocell can autonomously select portions of the spectrum in order to achieve more spectral efficiency and fairness. The solutions also strive...... for scalability to a large number of cells, stability and limited complexity. The work represents an evolution towards future cognitive femtocells. The issue of inter-cell interference among femtocells is thoroughly analyzed with game theory, graph theory and system-level simulations. These analyses show...

  8. Nanocrystal Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Gur, Ilan [Univ. of California, Berkeley, CA (United States)

    2006-01-01

    This dissertation presents the results of a research agenda aimed at improving integration and stability in nanocrystal-based solar cells through advances in active materials and device architectures. The introduction of 3-dimensional nanocrystals illustrates the potential for improving transport and percolation in hybrid solar cells and enables novel fabrication methods for optimizing integration in these systems. Fabricating cells by sequential deposition allows for solution-based assembly of hybrid composites with controlled and well-characterized dispersion and electrode contact. Hyperbranched nanocrystals emerge as a nearly ideal building block for hybrid cells, allowing the controlled morphologies targeted by templated approaches to be achieved in an easily fabricated solution-cast device. In addition to offering practical benefits to device processing, these approaches offer fundamental insight into the operation of hybrid solar cells, shedding light on key phenomena such as the roles of electrode-contact and percolation behavior in these cells. Finally, all-inorganic nanocrystal solar cells are presented as a wholly new cell concept, illustrating that donor-acceptor charge transfer and directed carrier diffusion can be utilized in a system with no organic components, and that nanocrystals may act as building blocks for efficient, stable, and low-cost thin-film solar cells.

  9. Hybrid Perovskites: Prospects for Concentrator Solar Cells.

    Science.gov (United States)

    Lin, Qianqian; Wang, Zhiping; Snaith, Henry J; Johnston, Michael B; Herz, Laura M

    2018-04-01

    Perovskite solar cells have shown a meteoric rise of power conversion efficiency and a steady pace of improvements in their stability of operation. Such rapid progress has triggered research into approaches that can boost efficiencies beyond the Shockley-Queisser limit stipulated for a single-junction cell under normal solar illumination conditions. The tandem solar cell architecture is one concept here that has recently been successfully implemented. However, the approach of solar concentration has not been sufficiently explored so far for perovskite photovoltaics, despite its frequent use in the area of inorganic semiconductor solar cells. Here, the prospects of hybrid perovskites are assessed for use in concentrator solar cells. Solar cell performance parameters are theoretically predicted as a function of solar concentration levels, based on representative assumptions of charge-carrier recombination and extraction rates in the device. It is demonstrated that perovskite solar cells can fundamentally exhibit appreciably higher energy-conversion efficiencies under solar concentration, where they are able to exceed the Shockley-Queisser limit and exhibit strongly elevated open-circuit voltages. It is therefore concluded that sufficient material and device stability under increased illumination levels will be the only significant challenge to perovskite concentrator solar cell applications.

  10. Stability of personality traits over a five-year period in Swedish patients with schizophrenia spectrum disorder and non-psychotic individuals: a study using the Swedish universities scales of personality.

    Science.gov (United States)

    Fagerberg, Tomas; Söderman, Erik; Petter Gustavsson, J; Agartz, Ingrid; Jönsson, Erik G

    2018-02-27

    Personality is considered as an important aspect in persons with psychotic disorders. Several studies have investigated personality in schizophrenia. However, no study has investigated stability of personality traits exceeding three years in patients with schizophrenia. This study aims to investigate the stability of personality traits over a five-year period among patients with schizophrenia and non-psychotic individuals and to evaluate case-control differences. Patients with psychotic disorders (n = 36) and non-psychotic individuals (n = 76) completed Swedish universities Scales of Personality (SSP) at two occasions five years apart. SSP scores were analysed for effect of time and case-control differences by multiple analysis of covariance (MANCOVA) and within-subjects correlation. MANCOVA within-subjects analysis did not show any effect of time. Thus, SSP mean scale scores did not significantly vary during the five-year interval. Within subject correlations (Spearman) ranged 0.30-0.68 and 0.54-0.75 for the different SSP scales in patients and controls, respectively. Patients scored higher than controls in SSP scales Somatic Trait Anxiety, Psychic Trait Anxiety, Stress Susceptibility, Lack of Assertiveness, Detachment, Embitterment, and Mistrust. The stability of the SSP personality trait was reasonably high among patients with psychotic disorder, although lower than among non-psychotic individuals, which is in accordance with previous research.

  11. Many channel spectrum unfolding

    International Nuclear Information System (INIS)

    Najzer, M.; Glumac, B.; Pauko, M.

    1980-01-01

    The principle of the ITER unfolding code as used for the many channel spectrum unfolding is described. Its unfolding ability is tested on seven typical neutron spectra. The effect of the initial spectrum approximation upon the solution is discussed

  12. Pulsar Emission Spectrum

    OpenAIRE

    Gruzinov, Andrei

    2013-01-01

    Emission spectrum is calculated for a weak axisymmetric pulsar. Also calculated are the observed spectrum, efficiency, and the observed efficiency. The underlying flow of electrons and positrons turns out to be curiously intricate.

  13. Autism Spectrum Disorder

    Science.gov (United States)

    ... Caregiver Education » Fact Sheets Autism Spectrum Disorder Fact Sheet What is autism spectrum disorder? What are some ... of mutations in individual genes but rather spontaneous coding mutations across many genes. De novo mutations may ...

  14. Long-lived charge-separated states in ligand-stabilized silver clusters

    KAUST Repository

    Pelton, Matthew; Tang, Yun; Bakr, Osman; Stellacci, Francesco

    2012-01-01

    Recently developed synthesis methods allow for the production of atomically monodisperse clusters of silver atoms stabilized in solution by aromatic thiol ligands, which exhibit intense absorption peaks throughout the visible and near-IR spectral regions. Here we investigated the time-dependent optical properties of these clusters. We observed two kinetic processes following ultrafast laser excitation of any of the absorption peaks: a rapid decay, with a time constant of 1 ps or less, and a slow decay, with a time constant that can be longer than 300 ns. Both time constants decrease as the polarity of the solvent increases, indicating that the two processes correspond to the formation and recombination, respectively, of a charge-separated state. The long lifetime of this state and the broad optical absorption spectrum mean that the ligand-stabilized silver clusters are promising materials for solar energy harvesting. © 2012 American Chemical Society.

  15. Long-lived charge-separated states in ligand-stabilized silver clusters

    KAUST Repository

    Pelton, Matthew

    2012-07-25

    Recently developed synthesis methods allow for the production of atomically monodisperse clusters of silver atoms stabilized in solution by aromatic thiol ligands, which exhibit intense absorption peaks throughout the visible and near-IR spectral regions. Here we investigated the time-dependent optical properties of these clusters. We observed two kinetic processes following ultrafast laser excitation of any of the absorption peaks: a rapid decay, with a time constant of 1 ps or less, and a slow decay, with a time constant that can be longer than 300 ns. Both time constants decrease as the polarity of the solvent increases, indicating that the two processes correspond to the formation and recombination, respectively, of a charge-separated state. The long lifetime of this state and the broad optical absorption spectrum mean that the ligand-stabilized silver clusters are promising materials for solar energy harvesting. © 2012 American Chemical Society.

  16. A nanophotonic solar thermophotovoltaic device.

    Science.gov (United States)

    Lenert, Andrej; Bierman, David M; Nam, Youngsuk; Chan, Walker R; Celanović, Ivan; Soljačić, Marin; Wang, Evelyn N

    2014-02-01

    The most common approaches to generating power from sunlight are either photovoltaic, in which sunlight directly excites electron-hole pairs in a semiconductor, or solar-thermal, in which sunlight drives a mechanical heat engine. Photovoltaic power generation is intermittent and typically only exploits a portion of the solar spectrum efficiently, whereas the intrinsic irreversibilities of small heat engines make the solar-thermal approach best suited for utility-scale power plants. There is, therefore, an increasing need for hybrid technologies for solar power generation. By converting sunlight into thermal emission tuned to energies directly above the photovoltaic bandgap using a hot absorber-emitter, solar thermophotovoltaics promise to leverage the benefits of both approaches: high efficiency, by harnessing the entire solar spectrum; scalability and compactness, because of their solid-state nature; and dispatchablility, owing to the ability to store energy using thermal or chemical means. However, efficient collection of sunlight in the absorber and spectral control in the emitter are particularly challenging at high operating temperatures. This drawback has limited previous experimental demonstrations of this approach to conversion efficiencies around or below 1% (refs 9, 10, 11). Here, we report on a full solar thermophotovoltaic device, which, thanks to the nanophotonic properties of the absorber-emitter surface, reaches experimental efficiencies of 3.2%. The device integrates a multiwalled carbon nanotube absorber and a one-dimensional Si/SiO2 photonic-crystal emitter on the same substrate, with the absorber-emitter areas optimized to tune the energy balance of the device. Our device is planar and compact and could become a viable option for high-performance solar thermophotovoltaic energy conversion.

  17. Upconversion in solar cells

    Science.gov (United States)

    2013-01-01

    The possibility to tune chemical and physical properties in nanosized materials has a strong impact on a variety of technologies, including photovoltaics. One of the prominent research areas of nanomaterials for photovoltaics involves spectral conversion. Modification of the spectrum requires down- and/or upconversion or downshifting of the spectrum, meaning that the energy of photons is modified to either lower (down) or higher (up) energy. Nanostructures such as quantum dots, luminescent dye molecules, and lanthanide-doped glasses are capable of absorbing photons at a certain wavelength and emitting photons at a different (shorter or longer) wavelength. We will discuss upconversion by lanthanide compounds in various host materials and will further demonstrate upconversion to work for thin-film silicon solar cells. PMID:23413889

  18. Limit sets for the discrete spectrum of complex Jacobi matrices

    International Nuclear Information System (INIS)

    Golinskii, L B; Egorova, I E

    2005-01-01

    The discrete spectrum of complex Jacobi matrices that are compact perturbations of the discrete Laplacian is studied. The precise stabilization rate (in the sense of order) of the matrix elements ensuring the finiteness of the discrete spectrum is found. An example of a Jacobi matrix with discrete spectrum having a unique limit point is constructed. These results are discrete analogues of Pavlov's well-known results on Schroedinger operators with complex potential on a half-axis.

  19. Solar Photovoltaic

    OpenAIRE

    Wang, Chen; Lu, Yuefeng

    2016-01-01

    In the 21st century, human demand for new energy sources is urgent, because the traditional fossil energy is unable to meet human needs, and the fossil resource will make pollution, in this situation, solar energy gradually into the vision of scientists. As science advances, humans can already extensive use of solar energy to generate electricity. Solar energy is an inexhaustible and clean energy. In the global energy crisis, environmental pollution is the growing problem of today. The us...

  20. Solar magnetohydrodynamics

    International Nuclear Information System (INIS)

    Priest, E.R.

    1982-01-01

    The book serves several purposes. First set of chapters gives a concise general introduction to solar physics. In a second set the basic methods of magnetohydrodynamics are developed. A third set of chapters is an account of current theories for observed phenomena. The book is suitable for a course in solar physics and it also provides a comprehensive review of present magnetohydrodynamical models in solar physics. (SC)

  1. The mass spectrum of interstellar clouds

    International Nuclear Information System (INIS)

    Dickey, J.M.; Garwood, R.W.

    1989-01-01

    The abundances of diffuse clouds and molecular clouds in the inner Galaxy and at the solar circle are compared. Using results of recent low-latitude 21 cm absorption studies, the number of diffuse clouds per kiloparsec along the line of sight is derived as a function of the cloud column density, under two assumptions relating cloud densities and temperatures. The density of clouds is derived as a function of cloud mass. The results are consistent with a single, continuous mass spectrum for interstellar clouds from less than 1 solar mass to 1,000,000 solar masses, with perhaps a change of slope at masses where the atomic and molecular mass fractions are roughly equal. 36 refs

  2. Solar constraints

    International Nuclear Information System (INIS)

    Provost, J.

    1984-01-01

    Accurate tests of the theory of stellar structure and evolution are available from the Sun's observations. The solar constraints are reviewed, with a special attention to the recent progress in observing global solar oscillations. Each constraint is sensitive to a given region of the Sun. The present solar models (standard, low Z, mixed) are discussed with respect to neutrino flux, low and high degree five-minute oscillations and low degree internal gravity modes. It appears that actually there do not exist solar models able to fully account for all the observed quantities. (Auth.)

  3. 8 years of Solar Spectral Irradiance Observations from the ISS with the SOLAR/SOLSPEC Instrument

    Science.gov (United States)

    Damé, L.; Bolsée, D.; Meftah, M.; Irbah, A.; Hauchecorne, A.; Bekki, S.; Pereira, N.; Cessateur, G.; Marchand, M.; Thiéblemont, R.; Foujols, T.

    2016-12-01

    Accurate measurements of Solar Spectral Irradiance (SSI) are of primary importance for a better understanding of solar physics and of the impact of solar variability on climate (via Earth's atmospheric photochemistry). The acquisition of a top of atmosphere reference solar spectrum and of its temporal and spectral variability during the unusual solar cycle 24 is of prime interest for these studies. These measurements are performed since April 2008 with the SOLSPEC spectro-radiometer from the far ultraviolet to the infrared (166 nm to 3088 nm). This instrument, developed under a fruitful LATMOS/BIRA-IASB collaboration, is part of the Solar Monitoring Observatory (SOLAR) payload, externally mounted on the Columbus module of the International Space Station (ISS). The SOLAR mission, with its actual 8 years duration, will cover almost the entire solar cycle 24. We present here the in-flight operations and performances of the SOLSPEC instrument, including the engineering corrections, calibrations and improved know-how procedure for aging corrections. Accordingly, a SSI reference spectrum from the UV to the NIR will be presented, together with its UV variability, as measured by SOLAR/SOLSPEC. Uncertainties on these measurements and comparisons with other instruments will be briefly discussed.

  4. Nature of a solar cyclicity

    International Nuclear Information System (INIS)

    Romanchuk, P.R.

    1981-01-01

    The paper contains a critical review of works on studying a cyclic character of solar activity. An introduction of cyclic curves with a frequency spectrum is established to be insolvent. The Wolf, Newcomb and Waldmeier approach seems to be useful. Some evidence is given in favour of the author's conception of solar activity ciclicity of a tide nature. It is accounted for a continuous double and single effect of planets, a resonant character of this effect due to which a 10-year period of Jupiter and Saturn is transformed into an 11-year cycle of activity [ru

  5. Wavenumber spectrum of whistler turbulence: Particle-in-cell simulation

    International Nuclear Information System (INIS)

    Saito, S.; Gary, S. Peter; Narita, Y.

    2010-01-01

    The forward cascade of decaying whistler turbulence is studied in low beta plasma to understand essential properties of the energy spectrum at electron scales, by using a two-dimensional electromagnetic particle-in-cell (PIC) simulation. This simulation demonstrates turbulence in which the energy cascade rate is greater than the dissipation rate at the electron inertial length. The PIC simulation shows that the magnetic energy spectrum of forward-cascaded whistler turbulence at electron inertial scales is anisotropic and develops a very steep power-law spectrum which is consistent with recent solar wind observations. A comparison of the simulated spectrum with that predicted by a phenomenological turbulence scaling model suggests that the energy cascade at the electron inertial scale depends on both magnetic fluctuations and electron velocity fluctuations, as well as on the whistler dispersion relation. Thus, not only kinetic Alfven turbulence but also whistler turbulence may explain recent solar wind observations of very steep magnetic spectra at short scales.

  6. Organic and hybrid solar cells

    CERN Document Server

    Huang, Hui

    2014-01-01

    This book delivers a comprehensive evaluation of organic and hybrid solar cells and identifies their fundamental principles and numerous applications. Great attention is given to the charge transport mechanism, donor and acceptor materials, interfacial materials, alternative electrodes, device engineering and physics, and device stability. The authors provide an industrial perspective on the future of photovoltaic technologies.

  7. Solar cooking

    Science.gov (United States)

    Over two billion people face fuel wood shortages, causing tremendous personal and environmental stress. Over 4 million people die prematurely from indoor air pollution. Solar cooking can reduce fuel wood consumption and indoor air pollution. Solar cooking has been practiced and published since th...

  8. Solar Sprint

    Science.gov (United States)

    Tabor, Richard; Anderson, Stephen

    2007-01-01

    In the "Solar Sprint" activity, students design, test, and race a solar-powered car built with Legos. The use of ratios is incorporated to simulate the actual work of scientists and engineers. This method encourages fourth-grade students to think about multiple variables and stimulates their curiosity when an activity doesn't come out as…

  9. The applications of Complexity Theory and Tsallis Non-extensive Statistics at Solar Plasma Dynamics

    Science.gov (United States)

    Pavlos, George

    2015-04-01

    As the solar plasma lives far from equilibrium it is an excellent laboratory for testing complexity theory and non-equilibrium statistical mechanics. In this study, we present the highlights of complexity theory and Tsallis non extensive statistical mechanics as concerns their applications at solar plasma dynamics, especially at sunspot, solar flare and solar wind phenomena. Generally, when a physical system is driven far from equilibrium states some novel characteristics can be observed related to the nonlinear character of dynamics. Generally, the nonlinearity in space plasma dynamics can generate intermittent turbulence with the typical characteristics of the anomalous diffusion process and strange topologies of stochastic space plasma fields (velocity and magnetic fields) caused by the strange dynamics and strange kinetics (Zaslavsky, 2002). In addition, according to Zelenyi and Milovanov (2004) the complex character of the space plasma system includes the existence of non-equilibrium (quasi)-stationary states (NESS) having the topology of a percolating fractal set. The stabilization of a system near the NESS is perceived as a transition into a turbulent state determined by self-organization processes. The long-range correlation effects manifest themselves as a strange non-Gaussian behavior of kinetic processes near the NESS plasma state. The complex character of space plasma can also be described by the non-extensive statistical thermodynamics pioneered by Tsallis, which offers a consistent and effective theoretical framework, based on a generalization of Boltzmann - Gibbs (BG) entropy, to describe far from equilibrium nonlinear complex dynamics (Tsallis, 2009). In a series of recent papers, the hypothesis of Tsallis non-extensive statistics in magnetosphere, sunspot dynamics, solar flares, solar wind and space plasma in general, was tested and verified (Karakatsanis et al., 2013; Pavlos et al., 2014; 2015). Our study includes the analysis of solar plasma time

  10. Solar system astrophysics background science and the inner solar system

    CERN Document Server

    Milone, Eugene F

    2008-01-01

    Solar System Astrophysics: A Text for the Science of Planetary Systems covers the field of solar system astrophysics beginning with basic tools of spherical astronomy, coordinate frames, and celestial mechanics. Historical introductions precede the development and discussion in most chapters. After a basic treatment of the two- and restricted three-body system motions in Background Science and the Inner Solar System, perturbations are discussed, followed by the Earth's gravitational potential field and its effect on satellite orbits. This is followed by analysis of the Earth-Moon system and the interior planets. In Planetary Atmospheres and the Outer Solar System, the atmospheres chapters include detailed discussions of circulation, applicable also to the subsequent discussion of the gas giants. The giant planets are discussed together, and the thermal excesses of three of them are highlighted. This is followed by chapters on moons and rings, mainly in the context of dynamical stability, comets and meteors, m...

  11. Stability Operations: Policy and Doctrine Awaiting Implementation

    Science.gov (United States)

    2013-03-01

    periods move through offense and defense (or reverse ) sequentially while stability is presented throughout the rotation. This causes stability to...The author’s personal experience in Afghanistan and having studied the complex nature of stability operations suggests the reverse is true. June...climate change, Euro/EU collapse, a democratic or collapsed China, a reformed Iran, nuclear war or WMD/cyber-attack, solar geomagnetic storms, U.S

  12. Solar thermal

    International Nuclear Information System (INIS)

    Jones, J.

    2006-01-01

    While wind power is widely acknowledged as the most developed of the 'new' renewables, the number two technology, in terms of installed capacity functioning worldwide, is solar heating, or solar thermal. The author has investigated recent industry reports on how these markets are developing. The authors of an International Energy Agency (IEA) survey studied 41 countries in depth at the end of 2004, revealing that 141 million m 3 - corresponding to an installed capacity of 98.4 GWth - were installed in the sample countries (these nations represent 3.74 billion people, about 57% of the world's population). The installed capacity within the areas studied represents approximately 85%-90% of the solar thermal market worldwide. The use of solar heating varies greatly between countries - even close neighbours - and between economic regions. Its uptake often has more to do with policy than solar resource. There is also different uptake of technology. In China, Europe and Japan, plants with flat-plate and evacuated tube collectors are used, mainly to heat water and for space heating. Unglazed plastic collectors, used mainly for swimming pool heating, meanwhile, dominate the North American markets. Though the majority of solar heating installations today are installed on domestic rooftops, the larger-scale installations should not be overlooked. One important part of the market is the hotel sector - in particular hotels in locations that serve the seasonal summer holiday market, where solar is extremely effective. Likewise hospitals and residential homes, multi-family apartment blocks and sports centres are all good examples of places where solar thermal can deliver results. There are also a growing number of industrial applications, where solar thermal can meet the hot water needs (and possibly more) of a range of industries, such as food processing and agriculture. The ability of solar to provide a heat source for cooling is expected to become increasingly important as

  13. Solar thermal

    Energy Technology Data Exchange (ETDEWEB)

    Jones, J.

    2006-07-15

    While wind power is widely acknowledged as the most developed of the 'new' renewables, the number two technology, in terms of installed capacity functioning worldwide, is solar heating, or solar thermal. The author has investigated recent industry reports on how these markets are developing. The authors of an International Energy Agency (IEA) survey studied 41 countries in depth at the end of 2004, revealing that 141 million m{sup 3} - corresponding to an installed capacity of 98.4 GWth - were installed in the sample countries (these nations represent 3.74 billion people, about 57% of the world's population). The installed capacity within the areas studied represents approximately 85%-90% of the solar thermal market worldwide. The use of solar heating varies greatly between countries - even close neighbours - and between economic regions. Its uptake often has more to do with policy than solar resource. There is also different uptake of technology. In China, Europe and Japan, plants with flat-plate and evacuated tube collectors are used, mainly to heat water and for space heating. Unglazed plastic collectors, used mainly for swimming pool heating, meanwhile, dominate the North American markets. Though the majority of solar heating installations today are installed on domestic rooftops, the larger-scale installations should not be overlooked. One important part of the market is the hotel sector - in particular hotels in locations that serve the seasonal summer holiday market, where solar is extremely effective. Likewise hospitals and residential homes, multi-family apartment blocks and sports centres are all good examples of places where solar thermal can deliver results. There are also a growing number of industrial applications, where solar thermal can meet the hot water needs (and possibly more) of a range of industries, such as food processing and agriculture. The ability of solar to provide a heat source for cooling is expected to become

  14. Solar energy: photovoltaics

    International Nuclear Information System (INIS)

    Goetzberger, A.; Voss, B.; Knobloch, J.

    1994-01-01

    This textbooks covers the following topics: foundations of photovoltaics, solar energy, P-N junctions, physics of solar cells, high-efficiency solar cells, technology of Si solar cells, other solar cells, photovoltaic applications. (orig.)

  15. ADAPTIVE FULL-SPECTRUM SOLOR ENERGY SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Byard D. Wood

    2004-04-01

    This RD&D project is a three year team effort to develop a hybrid solar lighting (HSL) system that transports solar light from a paraboloidal dish concentrator to a luminaire via a large core polymer fiber optic. The luminaire can be a device to distribute sunlight into a space for the production of algae or it can be a device that is a combination of solar lighting and electric lighting. A benchmark prototype system has been developed to evaluate the HSL system. Sunlight is collected using a one-meter paraboloidal concentrator dish with two-axis tracking. A secondary mirror consisting of eight planar-segmented mirrors directs the visible part of the spectrum to eight fibers (receiver) and subsequently to eight luminaires. This results in about 8,200 lumens incident at each fiber tip. Each fiber can illuminate about 16.7 m{sup 2} (180 ft{sup 2}) of office space. The IR spectrum is directed to a thermophotovoltaic (TPV) array to produce electricity. During this reporting period, the project team made advancements in the design of the second generation (Alpha) system. For the Alpha system, the eight individual 12 mm fibers have been replaced with a centralized bundle of 3 mm fibers. The TRNSYS Full-Spectrum Solar Energy System model has been updated and new components have been added. The TPV array and nonimaging device have been tested and progress has been made in the fiber transmission models. A test plan was developed for both the high-lumen tests and the study to determine the non-energy benefits of daylighting. The photobioreactor team also made major advancements in the testing of model scale and bench top lab-scale systems.

  16. Solar Newsletter | Solar Research | NREL

    Science.gov (United States)

    more about work by this consortium, which crosses national laboratories, on new materials and designs information on NREL's research and development of solar technologies. To receive new issues by email prize, focused on solar energy technologies, and will release the prize rules and open registration

  17. Solar Variability Magnitudes and Timescales

    Science.gov (United States)

    Kopp, Greg

    2015-08-01

    The Sun’s net radiative output varies on timescales of minutes to many millennia. The former are directly observed as part of the on-going 37-year long total solar irradiance climate data record, while the latter are inferred from solar proxy and stellar evolution models. Since the Sun provides nearly all the energy driving the Earth’s climate system, changes in the sunlight reaching our planet can have - and have had - significant impacts on life and civilizations.Total solar irradiance has been measured from space since 1978 by a series of overlapping instruments. These have shown changes in the spatially- and spectrally-integrated radiant energy at the top of the Earth’s atmosphere from timescales as short as minutes to as long as a solar cycle. The Sun’s ~0.01% variations over a few minutes are caused by the superposition of convection and oscillations, and even occasionally by a large flare. Over days to weeks, changing surface activity affects solar brightness at the ~0.1% level. The 11-year solar cycle has comparable irradiance variations with peaks near solar maxima.Secular variations are harder to discern, being limited by instrument stability and the relatively short duration of the space-borne record. Proxy models of the Sun based on cosmogenic isotope records and inferred from Earth climate signatures indicate solar brightness changes over decades to millennia, although the magnitude of these variations depends on many assumptions. Stellar evolution affects yet longer timescales and is responsible for the greatest solar variabilities.In this talk I will summarize the Sun’s variability magnitudes over different temporal ranges, showing examples relevant for climate studies as well as detections of exo-solar planets transiting Sun-like stars.

  18. Solar magnetohydrodynamics

    International Nuclear Information System (INIS)

    Priest, E.R.

    1982-01-01

    Solar MHD is an important tool for understanding many solar phenomena. It also plays a crucial role in explaining the behaviour of more general cosmical magnetic fields and plasmas, since the Sun provides a natural laboratory in which such behaviour may be studied. While terrestrial experiments are invaluable in demonstrating general plasma properties, conclusions from them cannot be applied uncritically to solar plasmas and have in the past given rise to misconceptions about solar magnetic field behaviour. Important differences between a laboratory plasma on Earth and the Sun include the nature of boundary conditions, the energy balance, the effect of gravity and the size of the magnetic Reynolds number (generally of order unity on the Earth and very much larger on the Sun). The overall structure of the book is as follows. It begins with two introductory chapters on solar observations and the MHD equations. Then the fundamentals of MHD are developed in chapters on magnetostatics, waves, shocks, and instabilities. Finally, the theory is applied to the solar phenomena of atmospheric heating, sunspots, dynamos, flares, prominences, and the solar wind. (Auth.)

  19. Solar collectors

    Energy Technology Data Exchange (ETDEWEB)

    Hullmann, H; Schmidt, B [Technische Univ. Hannover (Germany, F.R.). Inst. fuer Industrialisierung des Bauens

    1976-01-01

    The utilisation possibilities of solar energy for the energy supplying of buildings are becoming increasingly more significant. Solar research at the moment aims predominantly with a high level of efficiency and therefore making accessible a significant range of applications for solar technology. Parallel to this are attempts to effect the saving of energy, be it in the demand for energy-saving constructions or in the increasing development and application of rational energy utilisation by technologists. The most important point of these activities at the moment, is still technological methods.

  20. Solar neutrinos

    International Nuclear Information System (INIS)

    Schatzman, E.

    1983-01-01

    The solar energy is produced by a series of nuclear reactions taking place in the deep interior of the sun. Some of these reactions produce neutrinos which may be detected, the proper detection system being available. The results of the Davis experiment (with 37 Cl) are given, showing a deficiency in the solar neutrino flux. The relevant explanation is either a property of the neutrino or an important change in the physics of the solar models. The prospect of a new experiment (with 71 Ga) is important as it will decide which of the two explanations is correct [fr

  1. Origin of the solar system

    International Nuclear Information System (INIS)

    Hayashi, Chushiro; Nakazawa, Kiyoshi; Miyama, S.M.

    1989-01-01

    The study on the origin of the solar system entered a stage of synthetic and positivistic science around 1960, as the observation and the theory of protostars began to develop, the solar chemical composition became almost definite, and the amounts of chemical and mineralogical data greatly increased. In accordance with this scientific situation, the first research meeting in Japan on the origin of the solar system was held in 1965 at the Research Institute for Fundamental Physics, Kyoto University. It was discussed how a variety of the data on the solar system can be explained in a unified way. Since 1977, the workshop on the origin has been held annually. Through a series of the workshops, so-called Kyoto model has been talked and discussed frequently. For three years from 1985, the workshop in Kyoto was supported by the Ministry of Education, Science and Culture, and one of the main items of this grant was to publish the results of the workshop as the Supplement of the Progress of Theoretical Physics. The chronology of the solar system, the formation processes of protostars, the stability of solar nebulae, the physical processes in solar nebulae, the physical processes related to planetary growth, the growth of planets, and the formation of asteroids and meteorites are described in this book. (K.I.)

  2. Solar Pumped Lasers and Their Applications

    Science.gov (United States)

    Lee, Ja H.

    1991-01-01

    Since 1980, NASA has been pursuing high power solar lasers as part of the space power beaming program. Materials in liquid, solid, and gas phases have been evaluated against the requirements for solar pumping. Two basic characteristics of solar insolation, namely its diffuse irradiance and 5800 K blackbody-like spectrum, impose rather stringent requirements for laser excitation. However, meeting these requirements is not insurmountable as solar thermal energy technology has progressed today, and taking advantage of solar pumping lasers is becoming increasingly attractive. The high density photons of concentrated solar energy have been used for mainly electric power generation and thermal processing of materials by the DOE Solar Thermal Technologies Program. However, the photons can interact with materials through many other direct kinetic paths, and applications of the concentrated photons could be extended to processes requiring photolysis, photosynthesis, and photoexcitation. The use of solar pumped lasers on Earth seems constrained by economics and sociopolitics. Therefore, prospective applications may be limited to those that require use of quantum effects and coherency of the laser in order to generate extremely high value products and services when conventional and inexpensive means are ineffective or impossible. The new applications already proposed for concentrated solar photons, such as destruction of hazardous waste, production of renewable fuel, production of fertilizer, and air/water pollution controls, may benefit from the use of inexpensive solar pumped laser matched with the photochemical kinetics of these processes.

  3. Concentrating Solar Power Projects - Planta Solar 20 | Concentrating Solar

    Science.gov (United States)

    Power | NREL 20 This page provides information on Planta Solar 20, a concentrating solar power Solar's Planta Solar 20 (PS20) is a 20-megawatt power tower plant being constructed next to the PS10 tower and increasing incident solar radiation capture will increase net electrical power output by 10

  4. Viking solar corona experiment

    International Nuclear Information System (INIS)

    Tyler, G.L.; Brenkle, J.P.; Komarek, T.A.; Zygielbaum, A.I.

    1977-01-01

    The 1976 Mars solar conjunction resulted in complete occulations of the Viking spacecraft by the sun at solar minimum. During the conjunction period, coherent 3.5- and 13-cm wavelength radio waves from the orbiters passed through the solar corona and were received with the 64-m antennas of the NASA Deep Space Network. Data were obtained within at least 0.3 and 0.8 R/sub s/ of the photosphere at the 3.5- and 13-cm wavelengths, respectively. The data can be used to determine the plasma density integrated along the radio path, the velocity of density irregularities in the coronal plasma, and the spectrum of the density fluctuations in the plasma. Observations of integrated plasma density near the south pole of the sun generally agree with a model of the corona which has an 8:1 decrease in plasma density from the equator to the pole. Power spectra of the 3.5- and 13-cm signals at a heliocentric radial distance of about 2 R/sub s/ have a 1/2-power width of several hundred hertz and vary sharply with proximate geometric miss distance. Spectral broadening indicates a marked progressive increase in plasma irregularities with decreasing ray altitude at scales between about 1 and 100 km

  5. Nonlinear physical systems spectral analysis, stability and bifurcations

    CERN Document Server

    Kirillov, Oleg N

    2013-01-01

    Bringing together 18 chapters written by leading experts in dynamical systems, operator theory, partial differential equations, and solid and fluid mechanics, this book presents state-of-the-art approaches to a wide spectrum of new and challenging stability problems.Nonlinear Physical Systems: Spectral Analysis, Stability and Bifurcations focuses on problems of spectral analysis, stability and bifurcations arising in the nonlinear partial differential equations of modern physics. Bifurcations and stability of solitary waves, geometrical optics stability analysis in hydro- and magnetohydrodynam

  6. The Spectrum of Wind Power Fluctuations

    Science.gov (United States)

    Bandi, Mahesh

    2016-11-01

    Wind is a variable energy source whose fluctuations threaten electrical grid stability and complicate dynamical load balancing. The power generated by a wind turbine fluctuates due to the variable wind speed that blows past the turbine. Indeed, the spectrum of wind power fluctuations is widely believed to reflect the Kolmogorov spectrum; both vary with frequency f as f - 5 / 3. This variability decreases when aggregate power fluctuations from geographically distributed wind farms are averaged at the grid via a mechanism known as geographic smoothing. Neither the f - 5 / 3 wind power fluctuation spectrum nor the mechanism of geographic smoothing are understood. In this work, we explain the wind power fluctuation spectrum from the turbine through grid scales. The f - 5 / 3 wind power fluctuation spectrum results from the largest length scales of atmospheric turbulence of order 200 km influencing the small scales where individual turbines operate. This long-range influence spatially couples geographically distributed wind farms and synchronizes farm outputs over a range of frequencies and decreases with increasing inter-farm distance. Consequently, aggregate grid-scale power fluctuations remain correlated, and are smoothed until they reach a limiting f - 7 / 3 spectrum. This work was funded by the Collective Interactions Unit, OIST Graduate University, Japan.

  7. Solar prominences

    CERN Document Server

    Engvold, Oddbjørn

    2015-01-01

    This volume presents the latest research results on solar prominences, including new developments on e.g. chirality, fine structure, magnetism, diagnostic tools and relevant solar plasma physics. In 1875 solar prominences, as seen out of the solar limb, were described by P.A. Secchi in his book Le Soleil as "gigantic pink or peach-flower coloured flames". The development of spectroscopy, coronagraphy and polarimetry brought tremendous observational advances in the twentieth century. The authors present and discuss exciting new challenges (resulting from observations made by space and ground-based telescopes in the 1990s and the first decade of the 21st century) concerning the diagnostics of prominences, their formation, their life time and their eruption along with their impact in the heliosphere (including the Earth). The book starts with a general introduction of the prominence “object” with some historical background on observations and instrumentation. In the next chapter, the various forms of promine...

  8. Solar chulha

    Energy Technology Data Exchange (ETDEWEB)

    Jadhao, P. H. [Department of Physics J.D. Institute of Engg. & Tech. Yavatmal (India); Patrikar, S. R. [Department of Physics VNIT, Nagpur (India)

    2016-05-06

    The main goal of the proposed system is to transfer energy from sun to the cooking load that is located in the kitchen. The energy is first collected by the solar collector lens system and two curve bars of same radius of curvature are mounted parallel and adjacent to each other at different height the solar collector is clamed on this two bars such that solar collector is exactly perpendicular to sunlight. The topology includes an additional feature which is window in the wall through which the beam is collimated is directed in the of kitchen. The solar energy that is collected is directed by the mirror system into the kitchen, where it is redirected to cooking platform located in the kitchen. The special feature in this system full Indian meal can be made since cooking platform is indoors.

  9. Solar Radio

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Scientists monitor the structure of the solar corona, the outer most regions of the Sun's atmosphere, using radio waves (100?s of MHz to 10?s of GHz). Variations in...

  10. Solar Energy

    Science.gov (United States)

    Building Design and Construction, 1977

    1977-01-01

    Describes 21 completed projects now using solar energy for heating, cooling, or electricity. Included are elementary schools in Atlanta and San Diego, a technical school in Detroit, and Trinity University in San Antonio, Texas. (MLF)

  11. Solar neutrino experiments: An update

    International Nuclear Information System (INIS)

    Hahn, R.L.

    1993-01-01

    The situation in solar neutrino physics has changed drastically in the past few years, so that now there are four neutrino experiments in operation, using different methods to look at different regions of the solar neutrino energy spectrum. These experiments are the radiochemical 37 Cl Homestake detector, the realtime Kamiokande detector, and the different forms of radiochemical 71 Ga detectors used in the GALLEX and SAGE projects. It is noteworthy that all of these experiments report a deficit of observed neutrinos relative to the predictions of standard solar models (although in the case of the gallium detectors, the statistical errors are still relatively large). This paper reviews the basic principles of operation of these neutrino detectors, reports their latest results and discusses some theoretical interpretations. The progress of three realtime neutrino detectors that are currently under construction, SuperKamiok, SNO and Borexino, is also discussed

  12. Solar neutrino experiments: An update

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, R.L.

    1993-12-31

    The situation in solar neutrino physics has changed drastically in the past few years, so that now there are four neutrino experiments in operation, using different methods to look at different regions of the solar neutrino energy spectrum. These experiments are the radiochemical {sup 37}Cl Homestake detector, the realtime Kamiokande detector, and the different forms of radiochemical {sup 71}Ga detectors used in the GALLEX and SAGE projects. It is noteworthy that all of these experiments report a deficit of observed neutrinos relative to the predictions of standard solar models (although in the case of the gallium detectors, the statistical errors are still relatively large). This paper reviews the basic principles of operation of these neutrino detectors, reports their latest results and discusses some theoretical interpretations. The progress of three realtime neutrino detectors that are currently under construction, SuperKamiok, SNO and Borexino, is also discussed.

  13. Characterization of multicrystalline solar cells

    International Nuclear Information System (INIS)

    Malik, A.Q.; Chong Chew Hah; Chan Siang Khwang; Tan Kha Sheng; Lim Chee Ming

    2006-01-01

    The evaluation and assessment of the performance of photovoltaic (PV) cells in terms of measurable parameters requires the measurement of the current as a function of voltage, temperature, intensity, wind speed and spectrum. Most noticeable of all these parameters in the PV conversion efficiency η, defined as the maximum electrical power P max produced by the PV cell divided by the incident photon power P in which is measured with respect to standard test conditions (Sc). These conditions refer to the spectrum (AM 1.5), solar radiation intensity (1000 Wm -2 ), cell temperature (25 ± 2 degree C) and wind speed (2 mph). Tests under STC are carried out in the laboratory at a controlled environment. There have been several studies that analyze uncertainties in the laboratory measurement of solar cell efficiencies using different solar simulators and their transference to operational situations. Our preliminary results demonstrate that the short circuit current (I SC ) of the solar cell decreases when irradiance is less than 1000 Wm -2 irrespective of the working temperature of the cell

  14. Characterisation of multicrystalline solar cells

    Directory of Open Access Journals (Sweden)

    A.Q. Malik

    2017-10-01

    Full Text Available The evaluation and assessment of the performance of photovoltaic (PV cells in terms of measurable parameters requires the measurement of the current as a function of voltage, temperature, intensity, wind speed and spectrum. Mo st noticeable of all these parameters is the PV conversion efficiency η, defined as the maximum electrical power Pmax produced by the PV cell divided by the incident photon power P in which is measured with respect to standard test conditions (STC. These conditions refer to the spectrum (AM 1.5, solar radiation intensity (1000 Wm-2, cell temperature (25 ±2oC and wind speed (2 mph. Tests under STC are carried out in the laboratory at a controlled environment. There have been several studies that analyze uncertainties in the laboratory measurement of solar cell efficiencies using different solar simulators and their transference to operational situations. Our preliminary results demonstratethat the short circuit current (ISC of the solar cell decreases when irradiance is less than 1000 Wm-2 irrespective of the working temperature of the cell.

  15. The influence of solar system oscillation on the variability of the total solar irradiance

    Science.gov (United States)

    Yndestad, Harald; Solheim, Jan-Erik

    2017-02-01

    Total solar irradiance (TSI) is the primary quantity of energy that is provided to the Earth. The properties of the TSI variability are critical for understanding the cause of the irradiation variability and its expected influence on climate variations. A deterministic property of TSI variability can provide information about future irradiation variability and expected long-term climate variation, whereas a non-deterministic variability can only explain the past. This study of solar variability is based on an analysis of two TSI data series, one since 1700 A.D. and one since 1000 A.D.; a sunspot data series since 1610 A.D.; and a solar orbit data series from 1000 A.D. The study is based on a wavelet spectrum analysis. First, the TSI data series are transformed into a wavelet spectrum. Then, the wavelet spectrum is transformed into an autocorrelation spectrum to identify stationary, subharmonic and coincidence periods in the TSI variability. The results indicate that the TSI and sunspot data series have periodic cycles that are correlated with the oscillations of the solar position relative to the barycenter of the solar system, which is controlled by gravity force variations from the large planets Jupiter, Saturn, Uranus and Neptune. A possible explanation for solar activity variations is forced oscillations between the large planets and the solar dynamo. We find that a stationary component of the solar variability is controlled by the 12-year Jupiter period and the 84-year Uranus period with subharmonics. For TSI and sunspot variations, we find stationary periods related to the 84-year Uranus period. Deterministic models based on the stationary periods confirm the results through a close relation to known long solar minima since 1000 A.D. and suggest a modern maximum period from 1940 to 2015. The model computes a new Dalton-type sunspot minimum from approximately 2025 to 2050 and a new Dalton-type period TSI minimum from approximately 2040 to 2065.

  16. Solar Pump

    Science.gov (United States)

    Pique, Charles

    1987-01-01

    Proposed pump moves liquid by action of bubbles formed by heat of sun. Tube of liquid having boiling point of 100 to 200 degrees F placed at focal axis of cylindrical reflector. Concentrated sunlight boils liquid at focus, and bubbles of vapor rise in tube, carrying liquid along with them. Pressure difference in hot tube sufficient to produce flow in large loop. Used with conventional flat solar heating panel in completely solar-powered heat-storage system.

  17. 5G Spectrum Sharing

    OpenAIRE

    Nekovee, Maziar; Rudd, Richard

    2017-01-01

    In this paper an overview is given of the current status of 5G industry standards, spectrum allocation and use cases, followed by initial investigations of new opportunities for spectrum sharing in 5G using cognitive radio techniques, considering both licensed and unlicensed scenarios. A particular attention is given to sharing millimeter-wave frequencies, which are of prominent importance for 5G.

  18. Autism Spectrum Disorder (ASD)

    Science.gov (United States)

    ... Español (Spanish) Recommend on Facebook Tweet Share Compartir Autism spectrum disorder (ASD) is a developmental disability that can cause ... work. Autism: What's New MMWR article: Prevalence of Autism Spectrum Disorder Data Community Report Press release: Autism Prevalence Slightly ...

  19. Solar Schematic

    Science.gov (United States)

    1979-01-01

    The home shown at right is specially designed to accommodate solar heating units; it has roof planes in four directions, allowing placement of solar collectors for best exposure to the sun. Plans (bottom) and complete working blueprints for the solar-heated house are being marketed by Home Building Plan Service, Portland, Oregon. The company also offers an inexpensive schematic (center) showing how a homeowner only moderately skilled in the use of tools can build his own solar energy system, applicable to new or existing structures. The schematic is based upon the design of a low-cost solar home heating system built and tested by NASA's Langley Research Center; used to supplement a warm-air heating system, it can save the homeowner about 40 percent of his annual heating bill for a modest investment in materials and components. Home Building Plan Service saved considerable research time by obtaining a NASA technical report which details the Langley work. The resulting schematic includes construction plans and simplified explanations of solar heat collection, collectors and other components, passive heat factors, domestic hot water supply and how to work with local heating engineers.

  20. On line profile asymmetries in a solar flare

    Czech Academy of Sciences Publication Activity Database

    Prosecký, Tomáš; Kotrč, Pavel; Berlicki, A.

    2006-01-01

    Roč. 30, č. 1 (2006), s. 31-41 ISSN 1845-8319. [Central European Solar Physics Meeting /2./. Bairisch Kölldorf, 19.05.2005-21.05.2005] R&D Projects: GA AV ČR IAA3003203 Institutional research plan: CEZ:AV0Z10030501 Keywords : sun * solar flares * spectrum Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  1. The solar energy; L'Energie solaire

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2004-07-01

    This document provides information the today technology concerning the photovoltaic cells and presents the research programs in the domain: silver cells, black silicon, spherical cells, mini sensors, solar spectrum cells Hercules europe project of solar energy concentration. Many Internet addresses are provided. (A.L.B.)

  2. SNO results and neutrino magnetic moment solution to the solar ...

    Indian Academy of Sciences (India)

    that the solar neutrino deficit is due to the interaction of neutrino transition magnetic moment with the solar magnetic ... Another new feature in the analysis is that for the global analysis, we have replaced the spectrum by its centroid. ... rise to mean potentials Va for neutrinos which are proportional to the number density of.

  3. Solar cataract: A clinical report | Ahuama | Journal of Health and ...

    African Journals Online (AJOL)

    Solar Ultraviolet radiation is caractogenic, as there is increasing evidence implicating ultraviolet radiation as a risk factor in the aetiology of cataracts. Through absorption from sunlight exposure especially into the violet and of the visible range of the solar spectrum, cataract formation may occur due to physiochemical ...

  4. Front Cover: Solar RRL 3-4∕2017

    NARCIS (Netherlands)

    van Sark, W.G.J.H.M.; Moraitis, P.; Aalberts, Carlo; Drent, M.; Grasso, Thom; L'Ortye, Yves; Visscher, Marc; Westra, Mattijs; Plas, Rob; Planje, Wilco

    Luminescent solar concentrators consist of coloured plastic plates that concentrate sunlight to their sides where solar cells are mounted. Since their conception in the 1970s, novel dyes and nanocrystals have being developed for these concentrators, and it is time to show their full spectrum of

  5. Increasing the efficiency of solar thermal panels

    Science.gov (United States)

    Dobrnjac, M.; Latinović, T.; Dobrnjac, S.; Živković, P.

    2016-08-01

    The popularity of solar heating systems is increasing for several reasons. These systems are reliable, adaptable and pollution-free, because the renewable solar energy is used. There are many variants of solar systems in the market mainly constructed with copper pipes and absorbers with different quality of absorption surface. Taking into account the advantages and disadvantages of existing solutions, in order to increase efficiency and improve the design of solar panel, the innovative solution has been done. This new solar panel presents connection of an attractive design and the use of constructive appropriate materials with special geometric shapes. Hydraulic and thermotechnical tests that have been performed on this panel showed high hydraulic and structural stability. Further development of the solar panel will be done in the future in order to improve some noticed disadvantages.

  6. Phase fluctuations model for EM wave propagation through solar scintillation at superior solar conjunction

    Science.gov (United States)

    Xu, Guanjun; Song, Zhaohui

    2017-04-01

    Traveling solar wind disturbances have a significant influence on radio wave characteristics during the superior solar conjunction communication. This paper considers the impact of solar scintillation on phase fluctuations of electromagnetic (EM) wave propagation during the superior solar conjunction. Based on the Geometric Optics approximation, the close-form approximation model for phase fluctuations is developed. Both effects of anisotropic temporal variations function of plasma irregularities and their power spectrum are presented and analyzed numerically. It is found that phase fluctuations rapidly decrease with increasing Sun-Earth-Probe angle and decrease with increasing frequency at the rate of 1/f2. Moreover, the role of various features of the solar wind irregularities and their influence on the EM wave characteristic parameters is studied and discussed. Finally, we study the phase fluctuations of typical cases in order to better understand the impact of phase fluctuations in future deep space communication scenarios during solar conjunction periods.

  7. Model Atmosphere Spectrum Fit to the Soft X-Ray Outburst Spectrum of SS Cyg

    Directory of Open Access Journals (Sweden)

    V. F. Suleimanov

    2015-02-01

    Full Text Available The X-ray spectrum of SS Cyg in outburst has a very soft component that can be interpreted as the fast-rotating optically thick boundary layer on the white dwarf surface. This component was carefully investigated by Mauche (2004 using the Chandra LETG spectrum of this object in outburst. The spectrum shows broad ( ≈5 °A spectral features that have been interpreted as a large number of absorption lines on a blackbody continuum with a temperature of ≈250 kK. Because the spectrum resembles the photospheric spectra of super-soft X-ray sources, we tried to fit it with high gravity hot LTE stellar model atmospheres with solar chemical composition, specially computed for this purpose. We obtained a reasonably good fit to the 60–125 °A spectrum with the following parameters: Teff = 190 kK, log g = 6.2, and NH = 8 · 1019 cm−2, although at shorter wavelengths the observed spectrum has a much higher flux. The reasons for this are discussed. The hypothesis of a fast rotating boundary layer is supported by the derived low surface gravity.

  8. Present state of the study of 160-minutes solar oscillation

    International Nuclear Information System (INIS)

    Severny, A.B.; Kotov, V.A.; Tsap, T.T.

    1981-01-01

    Global oscillation of the Sun with a period of 160 min were first discovered in 1974 and since observed in Crimea during the last 6 years; they were confirmed, in 1976-1979, by Doppler measurements at Stanford (Scherrer et al., 1980) and quite recently by observations of Fossat and Grec at the south geographic pole. The average amplitude of the oscillation is about 0.5 m s -1 . The phase shows remarkable stability at the period 160.010 min and good agreement between different sites on the Earth; therefore, this oscillation should now be recognized as definitely of solar origin. It is probably accompanied by synchronous fluctuations in the IR brightness and radio-emission of the Sun, and exhibits a dependence of the amplitude on the phase of solar rotation (with a peak of power at 27.2 days). In agreement with results of the Birmingham group and the South Pole observation we also find evidence in favour of a discrete spectrum within the 5 min global oscillations of the Sun, with the average splitting of about 69,5 μHz in frequency. Strict gas-dynamical equations being solved in the adiabatic approximation for a polytropic sphere n = 3 display the pattern of radial oscillations with wave separated by 120 m time-intervals filled with high frequency (and split by 117 μHz) oscillations implying a similarity with the observed pattern. (orig.)

  9. Solar India - 82: national solar energy convention

    Energy Technology Data Exchange (ETDEWEB)

    1982-01-01

    This document is the proceedings of the Solar India - 82 conference, which was held 17-19 December 1982. The papers are organized into functional groupings which include: (1) solar radiation, (2) flat plate solar collectors and solar water heaters, (3) solar concentrators, (4) solar air heaters and dryers, (5) solar ponds and energy storage, (6) solar cookers, (7) solar stills, (8) selective coatings, (9) photovoltaics, (10) space heating and cooling, (11) bio-energy, and (12) miscellaneous papers. The vast majority of the papers describe work carried out in India, the vast majority of the papers also contain relatively readable abstracts.

  10. Solar Features - Solar Flares - Patrol

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The H-alpha Flare Patrol identifies time periods each day when the sun is being continuously monitored by select ground-based solar observatories.

  11. Solar Features - Solar Flares - SIDS

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Sudden Ionospheric Disturbance (SID) is any of several radio propagation anomalies due to ionospheric changes resulting from solar or geophysical events.

  12. Cermet coatings for solar Stirling space power

    International Nuclear Information System (INIS)

    Jaworske, Donald A.; Raack, Taylor

    2004-01-01

    Cermet coatings, molecular mixtures of metal and ceramic, are being considered for the heat inlet surface of a solar Stirling space power convertor. The role of the cermet coating is to absorb as much of the incident solar energy as possible. The ability to mix metal and ceramic at the atomic level offers the opportunity to tailor the composition and the solar absorptance of these coatings. Several candidate cermet coatings were created and their solar absorptance was characterized as-manufactured and after exposure to elevated temperatures. Coating composition was purposely varied through the thickness of the coating. As a consequence of changing composition, islands of metal are thought to form in the ceramic matrix. Computer modeling indicated that diffusion of the metal atoms played an important role in island formation while the ceramic was important in locking the islands in place. Much of the solar spectrum is absorbed as it passes through this labyrinth

  13. Stabilizing Niger

    DEFF Research Database (Denmark)

    Hahonou, Eric Komlavi

    international intervention in Niger. Their main objective is to secure their own strategic, economic and political interests by strengthening the Nigerien authorities through direct intervention and capacity building activities. For western states reinforcing state security institutions and stabilizing elite...

  14. Solar Energy Innovation Network | Solar Research | NREL

    Science.gov (United States)

    Energy Innovation Network Solar Energy Innovation Network The Solar Energy Innovation Network grid. Text version The Solar Energy Innovation Network is a collaborative research effort administered (DOE) Solar Energy Technologies Office to develop and demonstrate new ways for solar energy to improve

  15. Effect of band-aligned double absorber layers on photovoltaic characteristics of chemical bath deposited PbS/CdS thin film solar cells.

    Science.gov (United States)

    Ho Yeon, Deuk; Chandra Mohanty, Bhaskar; Lee, Seung Min; Soo Cho, Yong

    2015-09-23

    Here we report the highest energy conversion efficiency and good stability of PbS thin film-based depleted heterojunction solar cells, not involving PbS quantum dots. The PbS thin films were grown by the low cost chemical bath deposition (CBD) process at relatively low temperatures. Compared to the quantum dot solar cells which require critical and multistep complex procedures for surface passivation, the present approach, leveraging the facile modulation of the optoelectronic properties of the PbS films by the CBD process, offers a simpler route for optimization of PbS-based solar cells. Through an architectural modification, wherein two band-aligned junctions are stacked without any intervening layers, an enhancement of conversion efficiency by as much as 30% from 3.10 to 4.03% facilitated by absorption of a wider range of solar spectrum has been obtained. As an added advantage of the low band gap PbS stacked over a wide gap PbS, the devices show stability over a period of 10 days.

  16. Huge opportunity for solar cooling

    International Nuclear Information System (INIS)

    Rowe, Daniel

    2014-01-01

    's Charlestown Square Shopping Centre and Echuca Hospital. These systems join a number of others already in operation at the large commercial and industrial scale, as well as a smaller number of systems providing cooling to cafes and offices. The development in this area is being supported by CSIRO's Solar Cooling research team which provides development, modelling and design expertise across the spectrum of solar cooling variants, sizes and applications - from remote community food preservation in India, to large commercial and residential systems in Australia. The group also has industry test facilities to support the development and testing of solar air conditioning systems as well as conventional air conditioning technologies. The Australian Institute of Refrigeration Air Conditioning and Heating (AIRAH's) Solar Cooling Special Technical Group is also involved in developing the solar cooling industry in Australia with the aim of combating climate change by reducing greenhouse emissions from the residential and commercial building sectors. The group coordinates industry and research efforts and organises information exchange, educational and training events for interested technical and business representatives. Fact file- Solar cooling systems are essentially comprised of two parts - solar thermal collectors and a sorption chiller which convert the heat into useful cooling. Though a number of collector and chiller combinations exist, no one single approach has yet dominated. Corresponding with the type of chiller used, solar cooling systems are often grouped into three categories: absorption, adsorption and desiccant. During design, an appropriate collector technology will be chosen, typically either a parabolic, flat plate or evacuated tube collector. The optimal configuration is also determined in design, to align equipment characteristics with the conditions, environment and requirements presented by each application. Thus solar cooling has a number of variants

  17. A Martian PFS average spectrum: Comparison with ISO SWS

    Science.gov (United States)

    Formisano, V.; Encrenaz, T.; Fonti, S.; Giuranna, M.; Grassi, D.; Hirsh, H.; Khatuntsev, I.; Ignatiev, N.; Lellouch, E.; Maturilli, A.; Moroz, V.; Orleanski, P.; Piccioni, G.; Rataj, M.; Saggin, B.; Zasova, L.

    2005-08-01

    The evaluation of the planetary Fourier spectrometer performance at Mars is presented by comparing an average spectrum with the ISO spectrum published by Lellouch et al. [2000. Planet. Space Sci. 48, 1393.]. First, the average conditions of Mars atmosphere are compared, then the mixing ratios of the major gases are evaluated. Major and minor bands of CO 2 are compared, from the point of view of features characteristics and bands depth. The spectral resolution is also compared using several solar lines. The result indicates that PFS radiance is valid to better than 1% in the wavenumber range 1800-4200 cm -1 for the average spectrum considered (1680 measurements). The PFS monochromatic transfer function generates an overshooting on the left-hand side of strong narrow lines (solar or atmospheric). The spectral resolution of PFS is of the order of 1.3 cm -1 or better. A large number of narrow features to be identified are discovered.

  18. Quantum Dots for Solar Cell Application

    Science.gov (United States)

    Poudyal, Uma

    Solar energy has been anticipated as the most important and reliable source of renewable energy to address the ever-increasing energy demand. To harvest solar energy efficiently, diverse kinds of solar cells have been studied. Among these, quantum dot sensitized solar cells have been an interesting group of solar cells mainly due to tunable, size-dependent electronic and optical properties of quantum dots. Moreover, doping these quantum dots with transition metal elements such as Mn opens avenue for improved performance of solar cells as well as for spin based technologies. In this dissertation, Mn-doped CdSe QDs (Mn-CdSe) have been synthesized by Successive Ionic Layer Adsorption and Reaction (SILAR) method. They are used in solar cells to study the effect of Mn doping in the performance of solar cells. Incident photon to current-conversion efficiency (IPCE) is used to record the effect of Mn-doping. Intensity modulated photovoltage and photocurrent spectroscopy (IMVS/PS) has been used to study the carrier dynamics in these solar cells. Additionally, the magnetic properties of Mn-CdSe QDs is studied and its possible origin is discussed. Moreover, CdS/CdSe QDs have been used to study the effect of liquid, gel and solid electrolyte in the performance and stability of the solar cells. Using IPCE spectra, the time decay measurements are presented and the possible reactions between the QD and the electrolytes are explained.

  19. Climate hypersensitivity to solar forcing?

    Directory of Open Access Journals (Sweden)

    W. Soon

    2000-05-01

    Full Text Available We compare the equilibrium climate responses of a quasi-dynamical energy balance model to radiative forcing by equivalent changes in CO2, solar total irradiance (Stot and solar UV (SUV. The response is largest in the SUV case, in which the imposed UV radiative forcing is preferentially absorbed in the layer above 250 mb, in contrast to the weak response from global-columnar radiative loading by increases in CO2 or Stot. The hypersensitive response of the climate system to solar UV forcing is caused by strongly coupled feedback involving vertical static stability, tropical thick cirrus ice clouds and stratospheric ozone. This mechanism offers a plausible explanation of the apparent hypersensitivity of climate to solar forcing, as suggested by analyses of recent climatic records. The model hypersensitivity strongly depends on climate parameters, especially cloud radiative properties, but is effective for arguably realistic values of these parameters. The proposed solar forcing mechanism should be further confirmed using other models (e.g., general circulation models that may better capture radiative and dynamical couplings of the troposphere and stratosphere.Key words: Meteorology and atmospheric dynamics (climatology · general or miscellaneous · Solar physics · astrophysics · and astronomy (ultraviolet emissions

  20. Slowly varying component of extreme ultraviolet solar radiation and its relation to solar radio radiation

    Science.gov (United States)

    Chapman, R. D.; Neupert, W. M.

    1974-01-01

    A study of the correlations between solar EUV line fluxes and solar radio fluxes has been carried out. A calibration for the Goddard Space Flight Center EUV spectrum is suggested. The results are used to obtain an equation for the absolute EUV flux for several lines in the 150- to 400-A region and the total flux of 81 intense lines in the region, the 2800-MHz radio flux being used as independent variable.

  1. Solar energy. [New Zealand

    Energy Technology Data Exchange (ETDEWEB)

    Benseman, R.

    1977-10-15

    The potential for solar space heating and solar water heating in New Zealand is discussed. Available solar energy in New Zealand is indicated, and the economics of solar space and water heating is considered. (WHK)

  2. Inertial-range spectrum of whistler turbulence

    Directory of Open Access Journals (Sweden)

    Y. Narita

    2010-02-01

    Full Text Available We develop a theoretical model of an inertial-range energy spectrum for homogeneous whistler turbulence. The theory is a generalization of the Iroshnikov-Kraichnan concept of the inertial-range magnetohydrodynamic turbulence. In the model the dispersion relation is used to derive scaling laws for whistler waves at highly oblique propagation with respect to the mean magnetic field. The model predicts an energy spectrum for such whistler waves with a spectral index −2.5 in the perpendicular component of the wave vector and thus provides an interpretation about recent discoveries of the second inertial-range of magnetic energy spectra at high frequencies in the solar wind.

  3. Solarization soil

    International Nuclear Information System (INIS)

    Abou Ghraibe, W.

    1995-01-01

    Solar energy could be used in pest control, in soil sterilization technology. The technique consists of covering humid soils by plastic films steadily fixed to the soil. Timing must be in summer during 4-8 weeks, where soil temperature increases to degrees high enough to control pests or to produce biological and chemical changes. The technique could be applied on many pests soil, mainly fungi, bacteria, nematods, weeds and pest insects. The technique could be used in greenhouses as well as in plastic film covers or in orchards where plastic films present double benefits: soil sterilization and production of black mulch. Mechanism of soil solarization is explained. Results show that soil solarization can be used in pest control after fruit crops cultivation and could be a method for an integrated pest control. 9 refs

  4. Solar unit

    Energy Technology Data Exchange (ETDEWEB)

    Sukhanov, A M; Trushevskiy, S N; Tveryanovich, E V

    1982-01-01

    A solar unit is proposed which contains an inclined solar collector with supply and outlet pipelines, the first of which is connected to the source of a heat carrier, while the second is connected through the valve to the tank for collecting heated heat carrier equipped with a device for recovery. In order to improve the effectiveness of heating the heat carrier, it additionally contains a concentrator of solar radiation and a device for maintaining a level of the heat carrier in the collector in the zone of the focal spot of the concentrator, while the heat pipeline is connected to the source of the heat carrier with the help of a device for maintaining the level of the heat carrier.

  5. The marine diversity spectrum

    DEFF Research Database (Denmark)

    Reuman, Daniel C.; Gislason, Henrik; Barnes, Carolyn

    2014-01-01

    of taxonomy (all the species in a region regardless of clade) are much less studied but are equally important and will illuminate a different set of ecological and evolutionary processes. We develop and test a mechanistic model of how diversity varies with body mass in marine ecosystems. The model predicts...... the form of the diversity spectrum', which quantifies the distribution of species' asymptotic body masses, is a species analogue of the classic size spectrum of individuals, and which we have found to be a new and widely applicable description of diversity patterns. The marine diversity spectrum...... is predicted to be approximately linear across an asymptotic mass range spanning seven orders of magnitude. Slope -0 center dot 5 is predicted for the global marine diversity spectrum for all combined pelagic zones of continental shelf seas, and slopes for large regions are predicted to lie between -0 center...

  6. Autism Spectrum Disorder

    Centers for Disease Control (CDC) Podcasts

    This podcast discusses autism spectrum disorder (ASD), a developmental disability that causes problems with social, communication, and behavioral skills. CDC estimates that one in 68 children has been identified as having ASD.

  7. Fetal Alcohol Spectrum Disorders

    Science.gov (United States)

    Alcohol can harm your baby at any stage during a pregnancy. That includes the earliest stages, before ... can cause a group of conditions called fetal alcohol spectrum disorders (FASDs). Children who are born with ...

  8. Fast Spectrum Reactors

    CERN Document Server

    Todd, Donald; Tsvetkov, Pavel

    2012-01-01

    Fast Spectrum Reactors presents a detailed overview of world-wide technology contributing to the development of fast spectrum reactors. With a unique focus on the capabilities of fast spectrum reactors to address nuclear waste transmutation issues, in addition to the well-known capabilities of breeding new fuel, this volume describes how fast spectrum reactors contribute to the wide application of nuclear power systems to serve the global nuclear renaissance while minimizing nuclear proliferation concerns. Readers will find an introduction to the sustainable development of nuclear energy and the role of fast reactors, in addition to an economic analysis of nuclear reactors. A section devoted to neutronics offers the current trends in nuclear design, such as performance parameters and the optimization of advanced power systems. The latest findings on fuel management, partitioning and transmutation include the physics, efficiency and strategies of transmutation, homogeneous and heterogeneous recycling, in addit...

  9. Gluonium spectrum in QCD

    International Nuclear Information System (INIS)

    Dominguez, C.A.

    1987-02-01

    The scalar (0 ++ ) and the tensor (2 ++ ) gluonium spectrum is analyzed in the framework of QCD sum rules. Stable eigenvalue solutions, consistent with duality and low energy theorems, are obtained for the mass and width of these glueballs. (orig.)

  10. Coupling of Luminescent Solar Concentrators to Plasmonic Solar Cells

    Science.gov (United States)

    Wang, Shu-Yi

    To make inexpensive solar cells is a continuous goal for solar photovoltaic (PV) energy industry. Thin film solar cells of various materials have been developed and continue to emerge in order to replace bulk silicon solar cells. A thin film solar cell not only uses less material but also requires a less expensive refinery process. In addition, other advantages coming along with small thickness are higher open circuit voltage and higher conversion efficiency. However, thin film solar cells, especially those made of silicon, have significant optical losses. In order to address this problem, this thesis investigates the spectral coupling of thin films PV to luminescent solar concentrators (LSC). LSC are passive devices, consisting of plastic sheets embedded with fluorescent dyes which absorb part of the incoming radiation spectrum and emit at specific wavelength. The emitted light is concentrated by total internal reflection to the edge of the sheet, where the PVs are placed. Since the light emitted from the LSC edge is usually in a narrow spectral range, it is possible to employ diverse strategies to enhance PV absorption at the peak of the emission wavelength. Employing plasmonic nanostructures has been shown to enhance absorption of thin films via forward scattering, diffraction and localized surface plasmon. These two strategies are theoretically investigated here for improving the absorption and elevating the output power of a thin film solar cell. First, the idea of spectral coupling of luminescent solar concentrators to plasmonic solar cells is introduced to assess its potential for increasing the power output. This study is carried out employing P3HT/PC60BM organic solar cells and LSC with Lumogen Red dyes. A simplified spectral coupling analysis is employed to predict the power density, considering the output spectrum of the LSC equivalent to the emission spectrum of the dye and neglecting any angular dependence. Plasmonic tuning is conducted to enhance

  11. Formation of spectrum of accelerated particles and the hydromagnetic turbulence in the variable magnetic field

    International Nuclear Information System (INIS)

    Savane, Y. Sy; Diaby, I.; Faza Barry, M.; Lomonossov, V.

    2002-11-01

    We study the acceleration of charged particles by the variable magnetic field. The study is based on the determination of spectrum of accelerated particles and the spectrum of hydro magnetic turbulence. We plan the self-consistent system of equation and we also find out the solution of the system for the spectrum of particles and hydro magnetic turbulence with the conditions of effective acceleration in the cosmic space of solar system. (author)

  12. Spectrum and network measurements

    CERN Document Server

    Witte, Robert A

    2014-01-01

    This new edition of Spectrum and Network Measurements enables readers to understand the basic theory, relate it to measured results, and apply it when creating new designs. This comprehensive treatment of frequency domain measurements successfully consolidates all the pertinent theory into one text. It covers the theory and practice of spectrum and network measurements in electronic systems. It also provides thorough coverage of Fourier analysis, transmission lines, intermodulation distortion, signal-to-noise ratio and S-parameters.

  13. Solar cells

    International Nuclear Information System (INIS)

    1980-01-01

    A method of producing solar cells is described which consists of producing a substantially monocrystalline tubular body of silicon or other suitable semiconductor material, treating this body to form an annular rectifying junction and then cutting it longitudinally to form a number of nearly flat ribbons from which the solar cells are fabricated. The P=N rectifying junction produced by the formation of silicon dioxide on the layers at the inner and outer surfaces of the body can be formed by ion-implantation or diffusion. (U.K.)

  14. Nonlinear stability of Gardner breathers

    Science.gov (United States)

    Alejo, Miguel A.

    2018-01-01

    We show that breather solutions of the Gardner equation, a natural generalization of the KdV and mKdV equations, are H2 (R) stable. Through a variational approach, we characterize Gardner breathers as minimizers of a new Lyapunov functional and we study the associated spectral problem, through (i) the analysis of the spectrum of explicit linear systems (spectral stability), and (ii) controlling degenerated directions by using low regularity conservation laws.

  15. Detecting photovoltaic solar panels using hyperspectral imagery and estimating solar power production

    Science.gov (United States)

    Czirjak, Daniel

    2017-04-01

    Remote sensing platforms have consistently demonstrated the ability to detect, and in some cases identify, specific targets of interest, and photovoltaic solar panels are shown to have a unique spectral signature that is consistent across multiple manufacturers and construction methods. Solar panels are proven to be detectable in hyperspectral imagery using common statistical target detection methods such as the adaptive cosine estimator, and false alarms can be mitigated through the use of a spectral verification process that eliminates pixels that do not have the key spectral features of photovoltaic solar panel reflectance spectrum. The normalized solar panel index is described and is a key component in the false-alarm mitigation process. After spectral verification, these solar panel arrays are confirmed on openly available literal imagery and can be measured using numerous open-source algorithms and tools. The measurements allow for the assessment of overall solar power generation capacity using an equation that accounts for solar insolation, the area of solar panels, and the efficiency of the solar panels conversion of solar energy to power. Using a known location with readily available information, the methods outlined in this paper estimate the power generation capabilities within 6% of the rated power.

  16. Concentrating Solar Power Projects - Nevada Solar One | Concentrating Solar

    Science.gov (United States)

    Power | NREL Nevada Solar One This page provides information on Nevada Solar One, a concentrating solar power (CSP) project, with data organized by background, participants, and power plant configuration. Acciona Energy's Nevada Solar One is the third largest CSP plant in the world and the first plant

  17. Concentrating Solar Power Projects - Khi Solar One | Concentrating Solar

    Science.gov (United States)

    Power | NREL Khi Solar One This page provides information on Khi Solar One, a concentrating solar power (CSP) project, with data organized by background, parcipants and power plant configuration . Status Date: February 8, 2016 Project Overview Project Name: Khi Solar One Country: South Africa Location

  18. Autism spectrum disorder - Asperger syndrome

    Science.gov (United States)

    ... part of the larger developmental disorder category of autism spectrum disorder . ... American Psychiatric Association. Autism spectrum disorder. ... VA: American Psychiatric Publishing: 2013;50-59. Raviola GJ, ...

  19. Solar Cell Calibration and Measurement Techniques

    Science.gov (United States)

    Bailey, Sheila; Brinker, Dave; Curtis, Henry; Jenkins, Phillip; Scheiman, Dave

    2004-01-01

    The increasing complexity of space solar cells and the increasing international markets for both cells and arrays has resulted in workshops jointly sponsored by NASDA, ESA and NASA. These workshops are designed to obtain international agreement on standardized values for the AMO spectrum and constant, recommend laboratory measurement practices and establish a set of protocols for international comparison of laboratory measurements. A working draft of an ISO standard, WD15387, "Requirements for Measurement and Calibration Procedures for Space Solar Cells" was discussed with a focus on the scope of the document, a definition of primary standard cell, and required error analysis for all measurement techniques. Working groups addressed the issues of Air Mass Zero (AMO) solar constant and spectrum, laboratory measurement techniques, and te international round robin methodology. A summary is presented of the current state of each area and the formulation of the ISO document.

  20. Solar Energy and You.

    Science.gov (United States)

    Conservation and Renewable Energy Inquiry and Referral Service (DOE), Silver Spring, MD.

    This booklet provides an introduction to solar energy by discussing: (1) how a home is heated; (2) how solar energy can help in the heating process; (3) the characteristics of passive solar houses; (4) the characteristics of active solar houses; (5) how solar heat is stored; and (6) other uses of solar energy. Also provided are 10 questions to…

  1. The impact of turbulent renewable energy production on power grid stability and quality

    Science.gov (United States)

    Schmietendorf, Katrin; Peinke, Joachim; Kamps, Oliver

    2017-11-01

    Feed-in fluctuations induced by renewables are one of the key challenges to the stability and quality of electrical power grids. In particular short-term fluctuations disturb the system on a time scale, on which load balancing does not operate yet and the system is intrinsically governed by self-organized synchronization. Wind and solar power are known to be strongly non-Gaussian with intermittent increment statistics in these time scales. We investigate the impact of short-term wind fluctuations on the basis of a Kuramoto-like power grid model considering stability in terms of desynchronization and frequency and voltage quality aspects. We present a procedure to generate realistic feed-in fluctuations with temporal correlations, Kolmogorov power spectrum and intermittent increments. By comparison to correlated Gaussian noise of the same spectrum and Gaussian white noise, we found out that while the correlations are essential to capture the likelihood of severe outages, the intermittent nature of wind power has significant consequences on power quality: intermittency is directly transferred into frequency and voltage fluctuations yielding a novel type of fluctuations, which is beyond engineering status of knowledge.

  2. Application of Inorganic Materials in Organic Solar Cells%无机材料在有机太阳能电池中的应用

    Institute of Scientific and Technical Information of China (English)

    车广波; 袁晶; 苏斌; 刘春波; 赵静; 李丽丽

    2013-01-01

    Although organic materials have been widely utilized for the fabrications of organic solar cells as they are inexpensive,easily prepared and compatible with substrates,the development of organic solar cells has been hindered mainly due to their low carrier mobility,poor stability and unsatisfactory matching with the solar spectrum.On the other hand,inorganic materials have high electron mobility and absorption spectra matching with the solar spectrum.Therefore the power conversion efficiency of organic solar cells is still not competitive with those of inorganic solar cells.If the advantages of both organic and inorganic materials could be combined,the performance of organic solar cells would be enhanced.At present,some progresses have been made in inorganic-organic hybird solar cells.Usually,the inorganic materials were used in the acceptor layer,cathode buffer layer and anode buffer layer to improve the energy conversion efficiency of organic solar cells.In this article we discussed the applications of some inorganic materials in organic solar cells and the recent research progresses as well as the perspectives in this field.%无机材料电子迁移率高、光谱响应范围与太阳光谱匹配,而有机材料价格低廉、合成方法简单、容易制作在基底上,因此在太阳能电池中具有更广阔的应用前景.目前,阻碍有机太阳能电池发展的主要原因是材料的载流子迁移率低、器件稳定性差、吸收光谱与太阳光谱不匹配,导致光电转换效率较低.若能将有机、无机材料二者的优点相结合,将可提高有机太阳能电池的能量转换效率.目前的研究已经取得了一定进展,无机材料在受体层、阴极缓冲层、阳极缓冲层中的应用均不同程度地提高了有机太阳能电池的能量转换效率.本文综述了目前该领域的研究现状,并对今后的研究提出了展望.

  3. Consensus stability testing protocols for organic photovoltaic materials and devices

    DEFF Research Database (Denmark)

    Reese, Matthew O.; Gevorgyan, Suren; Jørgensen, Mikkel

    2011-01-01

    Procedures for testing organic solar cell devices and modules with respect to stability and operational lifetime are described. The descriptions represent a consensus of the discussion and conclusions reached during the first 3 years of the international summit on OPV stability (ISOS). The proced......Procedures for testing organic solar cell devices and modules with respect to stability and operational lifetime are described. The descriptions represent a consensus of the discussion and conclusions reached during the first 3 years of the international summit on OPV stability (ISOS...

  4. Discrete symmetries and solar neutrino mixing

    Energy Technology Data Exchange (ETDEWEB)

    Kapetanakis, D.; Mayr, P.; Nilles, H.P. (Physik Dept., Technische Univ. Muenchen, Garching (Germany) Max-Planck-Inst. fuer Physik, Werner-Heisenberg-Inst., Muenchen (Germany))

    1992-05-21

    We study the question of resonant solar neutrino mixing in the framework of the supersymmetric extension of the standard model. Discrete symmetries that are consistent with solar neutrino mixing and proton stability are classified. In the minimal model they are shown to lead to two distinct patterns of allowed dimension-four operators. Imposing anomaly freedom, only three different discrete Z{sub N}-symmetries (with N=2, 3, 6) are found to be phenomenologically acceptable. (orig.).

  5. Discrete symmetries and solar neutrino mixing

    International Nuclear Information System (INIS)

    Kapetanakis, D.; Mayr, P.; Nilles, H.P.

    1992-01-01

    We study the question of resonant solar neutrino mixing in the framework of the supersymmetric extension of the standard model. Discrete symmetries that are consistent with solar neutrino mixing and proton stability are classified. In the minimal model they are shown to lead to two distinct patterns of allowed dimension-four operators. Imposing anomaly freedom, only three different discrete Z N -symmetries (with N=2, 3, 6) are found to be phenomenologically acceptable. (orig.)

  6. Radiation resistant passivation of silicon solar cells

    International Nuclear Information System (INIS)

    Swanson, R.M.; Gan, J.Y.; Gruenbaum, P.E.

    1991-01-01

    This patent describes a silicon solar cell having improved stability when exposed to concentrated solar radiation. It comprises a body of silicon material having a major surface for receiving radiation, a plurality of p and n conductivity regions in the body for collecting electrons and holes created by impinging radiation, and a passivation layer on the major surface including a first layer of silicon oxide in contact with the body and a polycrystalline silicon layer on the first layer of silicon oxide

  7. Sistema Solar

    OpenAIRE

    Federación de Asociaciones de Astronomía Cielo de Comellas

    2011-01-01

    Lección sobre el Sistema Solar. Curso de Astronomía Básica, segunda edición, impartido por los miembros de la Federación de Asociaciones de Astronomía Cielo de Comellas. Casa de la Ciencia, sábados, del 24 de septiembre al 22 de octubre de 2011

  8. Solar satellites

    Energy Technology Data Exchange (ETDEWEB)

    Poher, C.

    1982-01-01

    A reference system design, projected costs, and the functional concepts of a satellite solar power system (SSPS) for converting sunlight falling on solar panels of a satellite in GEO to a multi-GW beam which could be received by a rectenna on earth are outlined. Electricity transmission by microwaves has been demonstrated, and a reference design system for supplying 5 GW dc to earth was devised. The system will use either monocrystalline Si or concentrator GaAs solar cells for energy collection in GEO. Development is still needed to improve the lifespan of the cells. Currently, the cell performance degrades 50 percent in efficiency after 7-8 yr in space. Each SSPS satellite would weigh either 34,000 tons (Si) or 51,000 tons (GaAs), thereby requiring the fabrication of a heavy lift launch vehicle or a single-stage-to-orbit transport in order to minimize launch costs. Costs for the solar panels have been estimated at $500/kW using the GaAs technology, with transport costs for materials to GEO being $40/kg.

  9. Solar Neutrinos

    Indian Academy of Sciences (India)

    7,81. The Chlorine experiment, located in the Homestake Gold Mine in Lead, South Dakota, was the first solar neutrino experiment to be set up. A tank of. 105 gallons of perchloroethylene in which the electron neu- trino reacts with chlorine to ...

  10. Solar satellites

    Science.gov (United States)

    Poher, C.

    A reference system design, projected costs, and the functional concepts of a satellite solar power system (SSPS) for converting sunlight falling on solar panels of a satellite in GEO to a multi-GW beam which could be received by a rectenna on earth are outlined. Electricity transmission by microwaves has been demonstrated, and a reference design system for supplying 5 GW dc to earth was devised. The system will use either monocrystalline Si or concentrator GaAs solar cells for energy collection in GEO. Development is still needed to improve the lifespan of the cells. Currently, the cell performance degrades 50 percent in efficiency after 7-8 yr in space. Each SSPS satellite would weigh either 34,000 tons (Si) or 51,000 tons (GaAs), thereby requiring the fabrication of a heavy lift launch vehicle or a single-stage-to-orbit transport in order to minimize launch costs. Costs for the solar panels have been estimated at $500/kW using the GaAs technology, with transport costs for materials to GEO being $40/kg.

  11. Macroeconomic stability

    DEFF Research Database (Denmark)

    Jespersen, Jesper

    2004-01-01

    It is demonstrated that full employment and sustainable development not necessarily are conflicting goals. On the other hand macroeconomic stability cannot be obtained without a deliberate labour sharing policy and a shift in the composition of private consumption away from traditional material...

  12. Stabilized superconductors

    International Nuclear Information System (INIS)

    Wong, J.

    1975-01-01

    The stable, high field, high current composite wire comprises multiple filaments in a depleted bronze matrix, each filament comprising a type II superconducting, beta-tungsten structure, intermetallic compound layer jacketing and metallurgically bonded to a stabilizing copper core, directly or via an intermediate layer of refractory metal

  13. Renewable energy worldwide outlooks: solar energy

    International Nuclear Information System (INIS)

    Darnell, J.R.

    1994-01-01

    Solar energy yield is weak because it is very diffuse. The solar energy depends on the weather. The collectors need the beam radiation. Wavelength is important for some applications that include not only the visible spectrum but also infrared and ultraviolet radiation. The areas of the greatest future population growth are high on solar energy resources. We have different types of conversion systems where energy can be converted from solar to electric or thermal energy. Photovoltaic cells are made of silicone or gallium arsenide, this latter for the space use. For the solar energy applications there is a storage problem: electric batteries or superconducting magnets. Today, the highest use of solar energy is in the low temperature thermal category with over 90% of the world contribution from this energy. The penetration of solar energy will be higher in rural areas than in urban regions. But there are technical, institutional, economic constraints. In spite of that the use of solar energy would be increasing and will go on to increase thereafter. The decreasing costs over time are a real phenomenon and there is a broad public support for increased use of that energy. 15 figs

  14. Parabolic solar concentrator

    Science.gov (United States)

    Tecpoyotl-Torres, M.; Campos-Alvarez, J.; Tellez-Alanis, F.; Sánchez-Mondragón, J.

    2006-08-01

    In this work we present the basis of the solar concentrator design, which has is located at Temixco, Morelos, Mexico. For this purpose, this place is ideal due to its geographic and climatic conditions, and in addition, because it accounts with the greatest constant illumination in Mexico. For the construction of the concentrator we use a recycled parabolic plate of a telecommunications satellite dish (NEC). This plate was totally covered with Aluminum. The opening diameter is of 332 cm, the focal length is of 83 cm and the opening angle is of 90°. The geometry of the plate guaranties that the incident beams, will be collected at the focus. The mechanical treatment of the plate produces an average reflectance of 75% in the visible region of the solar spectrum, and of 92% for wavelengths up to 3μm in the infrared region. We obtain up to 2000°C of temperature concentration with this setup. The reflectance can be greatly improved, but did not consider it as typical practical use. The energy obtained can be applied to conditions that require of those high calorific energies. In order to optimize the operation of the concentrator we use a control circuit designed to track the apparent sun position.

  15. The monolithic multicell: a tool for testing material components in dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Pettersson, H.; Gruszecki, T. [IVF Industrial Research and Development Corporation, Moelndal (Sweden); Bernhard, R. [IVF Industrial Research and Development Corporation, Moelndal (Sweden); The Royal Institute of Technology, Stockholm (Sweden). Center of Molcular Devices, Department of Chemistry; Haeggman, L.; Gorlov, M.; Boschloo, G.; Edvinsson, T.; Kloo, L.; Hagfeldt, A. [The Royal Institute of Technology, Stockholm (Sweden). Center of Molcular Devices, Department of Chemistry

    2006-07-01

    A multicell is presented as a tool for testing material components in encapsulated dye-sensitized solar cells. The multicell is based on a four-layer monolithic cell structure and an industrial process technology. Each multicell plate includes 24 individual well-encapsulated cells. A sulfur lamp corrected to the solar spectrum has been used to characterize the cells. Efficiencies up to 6.8% at a light-intensity of 1000 W/m{sup su2} (up to 7.5% at 250 W/m{sup 2}) have been obtained with an electrolyte solution based on {upsilon}-butyrolactone. Additionally, a promising long-term stability at cell efficiencies close to 5% at 1000 W/m{sup 2} has been obtained with an electrolyte based on glutaronitrile. The reproducibility of the cell performance before and after exposure to accelerated testing has been high. This means that the multicell can be used as an efficient tool for comparative performance and stability tests. (author)

  16. 8 years of Solar Spectral Irradiance Variability Observed from the ISS with the SOLAR/SOLSPEC Instrument

    Science.gov (United States)

    Damé, Luc; Bolsée, David; Meftah, Mustapha; Irbah, Abdenour; Hauchecorne, Alain; Bekki, Slimane; Pereira, Nuno; Cessateur, Marchand; Gäel; , Marion; et al.

    2016-10-01

    Accurate measurements of Solar Spectral Irradiance (SSI) are of primary importance for a better understanding of solar physics and of the impact of solar variability on climate (via Earth's atmospheric photochemistry). The acquisition of a top of atmosphere reference solar spectrum and of its temporal and spectral variability during the unusual solar cycle 24 is of prime interest for these studies. These measurements are performed since April 2008 with the SOLSPEC spectro-radiometer from the far ultraviolet to the infrared (166 nm to 3088 nm). This instrument, developed under a fruitful LATMOS/BIRA-IASB collaboration, is part of the Solar Monitoring Observatory (SOLAR) payload, externally mounted on the Columbus module of the International Space Station (ISS). The SOLAR mission, with its actual 8 years duration, will cover almost the entire solar cycle 24. We present here the in-flight operations and performances of the SOLSPEC instrument, including the engineering corrections, calibrations and improved know-how procedure for aging corrections. Accordingly, a SSI reference spectrum from the UV to the NIR will be presented, together with its variability in the UV, as measured by SOLAR/SOLSPEC for 8 years. Uncertainties on these measurements and comparisons with other instruments will be briefly discussed.

  17. Stability of Anthocyanin Sensitized TiO2 Photoelectrochemical (PEC ...

    African Journals Online (AJOL)

    Solar cells fabricated from these electrodes gave overall conversion efficiencies of 3.16% for delphinidin purple and 2.97% for C35D. RuL dye sensitized solar cell gave 4.84%. The cells\\' stability performance in terms of photovoltage was found to drop with time of exposure. However the cells still exhibited I-V characteristics ...

  18. Concentrated sunlight for organic solar cells

    DEFF Research Database (Denmark)

    Tromholt, Thomas

    2010-01-01

    . A high solar intensity study of inverted P3HT:PCBM solar cells is presented. Performance peak positions were found to be in the range of 1-5 suns, with smaller cells peaking at higher solar concentrations. Additionally, concentrated sunlight is demonstrated as a practical tool for accelerated stability...... were degraded resulting in acceleration factors in the range of 19-55. This shows that concentrated sunlight can be used as qualitatively to determine the lifetime of polymers under highly accelerated conditions....

  19. Collecting Solar Energy. Solar Energy Education Project.

    Science.gov (United States)

    O'Brien, Alexander

    This solar energy learning module for use with junior high school students offers a list of activities, a pre-post test, job titles, basic solar energy vocabulary, and diagrams of solar energy collectors and installations. The purpose is to familiarize students with applications of solar energy and titles of jobs where this knowledge could be…

  20. Investigation of advanced nanostructured multijunction photoanodes for enhanced solar hydrogen generation via water splitting

    Science.gov (United States)

    Ishihara, Hidetaka

    As the worldwide demand for fossil-based fuel increases every day and the fossil reserve continues to be depleted, the need for alternative/renewable energy sources has gained momentum. Electric, hybrid, and hydrogen cars have been at the center of discussion lately among consumers, automobile manufacturers, and politicians, alike. The development of a fuel-cell based engine using hydrogen has been an ambitious research area over the last few decades-ever since Fujishima showed that hydrogen can be generated via the solar-energy driven photo-electrolytic splitting of water. Such solar cells are known as Photo-Electro-Chemical (PEC) solar cells. In order to commercialize this technology, various challenges associated with photo-conversion efficiency, chemical corrosion resistance, and longevity need to be overcome. In general, metal oxide semiconductors such as titanium dioxide (TiO 2, titania) are excellent candidates for PEC solar cells. Titania nanotubes have several advantages, including biocompatibility and higher chemical stability. Nevertheless, they can absorb only 5-7% of the solar spectrum which makes it difficult to achieve the higher photo-conversion efficiency required for successful commercial applications. A two-prong approach was employed to enhance photo-conversion efficiency: 1) surface modification of titania nanotubes using plasma treatment and 2) nano-capping of the titania nanotubes using titanium disilicide. The plasma surface treatment with N2 was found to improve the photo-current efficiency of titania nanotubes by 55%. Similarly, a facile, novel approach of nano-capping titania nanotubes to enhance their photocurrent response was also investigated. Electrochemically anodized titania nanotubes were capped by coating a 25 nm layer of titanium disilicide using RF magnetron sputtering technique. The optical properties of titania nanotubes were not found to change due to the capping; however, a considerable increase (40%) in the photocurrent