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Sample records for absorbers solar

  1. Metasurface Broadband Solar Absorber

    Azad, Abul K.; Kort-Kamp, Wilton J. M.; Milan Sykora; Nina R. Weisse-Bernstein; Luk, Ting S.; Antoinette J. Taylor; Dalvit, Diego A. R.; Hou-Tong Chen

    2016-01-01

    We demonstrate a broadband, polarization independent, omnidirectional absorber based on a metallic metasurface architecture, which accomplishes greater than 90% absorptance in the visible and near-infrared range of the solar spectrum, and exhibits low emissivity at mid- and far-infrared wavelengths. The complex unit cell of the metasurface solar absorber consists of eight pairs of gold nano-resonators that are separated from a gold ground plane by a thin silicon dioxide spacer. Our experiment...

  2. Metasurface Broadband Solar Absorber

    Azad, A K; Sykora, M; Weisse-Bernstein, N R; Luk, T S; Taylor, A J; Dalvit, D A R; Chen, H -T

    2015-01-01

    We demonstrate a broadband, polarization independent, omnidirectional absorber based on a metallic metasurface architecture, which accomplishes greater than 90% absorptance in the visible and near-infrared range of the solar spectrum, and exhibits low emissivity at mid- and far-infrared wavelengths. The complex unit cell of the metasurface solar absorber consists of eight pairs of gold nano-resonators that are separated from a gold ground plane by a thin silicon dioxide spacer. Our experimental measurements reveal high-performance absorption over a wide range of incidence angles for both s- and p-polarizations. We also investigate numerically the frequency-dependent field and current distributions to elucidate how the absorption occurs within the metasurface structure. Furthermore, we discuss the potential use of our metasurface absorber design in solar thermophotovoltaics by exploiting refractory plasmonic materials.

  3. Metasurface Broadband Solar Absorber

    Azad, Abul K.; Kort-Kamp, Wilton J. M.; Sykora, Milan; Weisse-Bernstein, Nina R.; Luk, Ting S.; Taylor, Antoinette J.; Dalvit, Diego A. R.; Chen, Hou-Tong

    2016-02-01

    We demonstrate a broadband, polarization independent, wide-angle absorber based on a metallic metasurface architecture, which accomplishes greater than 90% absorptance in the visible and near-infrared range of the solar spectrum, and exhibits low absorptivity (emissivity) at mid- and far-infrared wavelengths. The complex unit cell of the metasurface solar absorber consists of eight pairs of gold nano-resonators that are separated from a gold ground plane by a thin silicon dioxide spacer. Our experimental measurements reveal high-performance absorption over a wide range of incidence angles for both s- and p-polarizations. We also investigate numerically the frequency-dependent field and current distributions to elucidate how the absorption occurs within the metasurface structure.

  4. Manufacturing of Solar Absorber by Unconventional Methods

    Mrňa, Libor; Lidmila, Z.; Podaný, K.; Forejt, M.; Kubíček, J.

    Ostrava: TANGER Ltd, 2012. ISBN 978-80-87294-29-1. [METAL 2012. International Conference on Metallurgy and Materials /21./. Brno (CZ), 23.05.2012-25.05.2012] R&D Projects: GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : solar absorber * drawing in flexible tools * laser welding * austenitic steel Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  5. A review of cermet-based spectrally selective solar absorbers

    Cao, Feng; McEnaney, Kenneth; Chen, Gang; Ren, Zhifeng

    2013-01-01

    Spectrally selective solar absorbers harvest solar energy in the form of heat. Solar absorbers using cermet-based coatings demonstrate a high absorptance of the solar spectrum and a low emittance in the infrared (IR) regime. Extensive work has been done to optimize cermet-based solar absorbers to achieve high performance by exploring different cermet (ceramic–metal composite) materials and film configurations through different preparation techniques such as electrodeposition, sputtering, puls...

  6. Broadband metasurface absorber for solar thermal applications

    Wan, C.; Chen, L.; Cryan, M. J.

    2015-12-01

    In this paper we propose a broadband polarization-independent selective absorber for solar thermal applications. It is based on a metal-dielectric-metal metasurface structure, but with an interlayer of absorbing amorphous carbon rather than a low loss dielectric. Optical absorbance results derived from finite difference time domain modelling are shown for ultra-thin carbon layers in air and on 200 nm of gold for a range of carbon thicknesses. A gold-amorphous carbon-gold trilayer with a top layer consisting of a 1D grating is then optimised in 2D to give a sharp transition from strong absorption up to 2 μm to strong reflection above 2 μm resulting in good solar selective performance. The gold was replaced by the high-melting-point metal tungsten, which is shown to have very similar performance to the gold case. 3D simulations then show that the gold-based structure performs well as a square periodic array of squares, however there is low absorption around 400 nm. A cross-based structure is found to increase this absorption without significantly reducing the performance at longer wavelengths.

  7. Colorful solar selective absorber integrated with different colored units.

    Chen, Feiliang; Wang, Shao-Wei; Liu, Xingxing; Ji, Ruonan; Li, Zhifeng; Chen, Xiaoshuang; Chen, Yuwei; Lu, Wei

    2016-01-25

    Solar selective absorbers are the core part for solar thermal technologies such as solar water heaters, concentrated solar power, solar thermoelectric generators and solar thermophotovoltaics. Colorful solar selective absorber can provide new freedom and flexibility beyond energy performance, which will lead to wider utilization of solar technologies. In this work, we present a monolithic integration of colored solar absorber array with different colors on a single substrate based on a multilayered structure of Cu/TiN(x)O(y)/TiO(2)/Si(3)N(4)/SiO(2). A colored solar absorber array with 16 color units is demonstrated experimentally by using combinatorial deposition technique via changing the thickness of SiO(2) layer. The solar absorptivity and thermal emissivity of all the color units is higher than 92% and lower than 5.5%, respectively. The colored solar selective absorber array can have colorful appearance and designable patterns while keeping high energy performance at the same time. It is a new candidate for a number of solar applications, especially for architecture integration and military camouflage. PMID:26832602

  8. Glueing of solar absorbers; Solarabsorber kleben

    Berner, Joachim

    2012-04-20

    Bonding technologies in absorber fabrication are evolving. After soldering, ultrasonic welding and laser welding, glueing is the latest development. The Go Innovate AG company developed a process for glueing the most varied absorber materials.

  9. Absorber Alignment Measurement Tool for Solar Parabolic Trough Collectors: Preprint

    Stynes, J. K.; Ihas, B.

    2012-04-01

    As we pursue efforts to lower the capital and installation costs of parabolic trough solar collectors, it is essential to maintain high optical performance. While there are many optical tools available to measure the reflector slope errors of parabolic trough solar collectors, there are few tools to measure the absorber alignment. A new method is presented here to measure the absorber alignment in two dimensions to within 0.5 cm. The absorber alignment is measured using a digital camera and four photogrammetric targets. Physical contact with the receiver absorber or glass is not necessary. The alignment of the absorber is measured along its full length so that sagging of the absorber can be quantified with this technique. The resulting absorber alignment measurement provides critical information required to accurately determine the intercept factor of a collector.

  10. Research On Solar Energy Collector With Cell Polycarbonate Absorber

    Putāns, Henriks; Zagorska, Viktorija; Ziemelis, Imants; Jesko, Zanis

    2015-01-01

    A flat plate solar collector with cell polycarbonate absorber and transparent cover has been made and its experimental investigation carried out. The collector consists of a wooden box, into which, a layer of heat insulation with a mirror film and 4 mm thick cell polycarbonate sheet, as the absorber, are placed. The coherence between collector’s efficiency, heat carrier and ambient air temperature, as well as intensity of the solar radiation and heat power in the experimental investigation ha...

  11. Absorber design for a Scheffler-Type Solar Concentrator

    Highlights: • Receiver and absorber design methodology based in a solar image in the focal surface. • Stirling absorber dimensions based in a solar image in the focal surface of a STSC. • Comparative study of a solar image in the focal surface from different optical model. • A Monte-Carlo ray-tracing method was used to set STSC cavity receiver aperture. - Abstract: Ray tracing software, digital close range photogrammetry and the Monte-Carlo ray-tracing method have proven to be precise and efficient measurement techniques for the assessment of the shape accuracies of solar concentrators and their components. This paper presents a new method and results for the geometric aspect of a focal image for a Scheffler-Type Solar Concentrator (STSC) using ray tracing, digital close range photogrammetry and the Monte-Carlo ray-tracing method to establish parameters that allow for the design of the most suitable absorber and receiver geometry for coupling the STSC to a Stirling engine. The results of the ray tracing software, digital close range photogrammetry and Monte-Carlo ray tracing technique in STSC are associated with a Stirling receiver. When using the method to perform simulations, we found that the most suitable solar image geometry has an elliptical shape and area of 0.0065 m2 on average. Although this result is appropriate, the geometry of the receiver is modified to fit an absorber and cavity receiver to improve the heat transfer by radiation

  12. Thin-film absorber for a solar collector

    Wilhelm, W.G.

    1982-02-09

    This invention pertains to energy absorbers for solar collectors, and more particularly to high performance thin film absorbers. The solar collectors comprising the absorber of this invention overcome several problems seen in current systems, such as excessive hardware, high cost and unreliability. In the preferred form, the apparatus features a substantially rigid planar frame with a thin film window bonded to one planar side of the frame. An absorber in accordance with the present invention is comprised of two thin film layers that are sealed perimetrically. In a preferred embodiment, thin film layers are formed from a metal/plastic laminate. The layers define a fluid-tight planar envelope of large surface area to volume through which a heat transfer fluid flows. The absorber is bonded to the other planar side of the frame. The thin film construction of the absorber assures substantially full envelope wetting and thus good efficiency. The window and absorber films stress the frame adding to the overall strength of the collector.

  13. Water heating solar system using collector with polycarbonate absorber surface

    Souza, Luiz Guilherme Meira de; Sodre, Dilton; Cavalcanti, Eduardo Jose Cidade; Souza, Luiz Guilherme Vieira Meira de; Mendes, Jose Ubiragi de Lima [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)], e-mails: lguilherme@dem.ufrn.br, diltonsodre@ifba.edu.br, ubiragi@ct.ufrn.br

    2010-07-01

    It is presented s solar collector to be used in a heating water for bath system, whose main characteristics are low cost and easy fabrication and assembly processes. The collector absorber surface consists of a polycarbonate plate with an area of 1.5 m{sup 2}. The water inlet and outlet are made of PVC 50mm, and were coupled to a 6mm thick polycarbonate plate using fiberglass resin. A 200 liters thermal reservoir will be used. This reservoir is also alternative. The absorber heating system works under thermo-siphon regimen. Thermal parameters will be evaluated to prove the feasibility of the studied solar heating system to obtain bath water for a four people family. (author)

  14. Solar Biogas Digester with Built-In Reverse Absorber Heater

    Karimov, Khasan S.; Muhammad Abid

    2013-01-01

    In this work the design, fabrication and investigation of a solar biogas digester with built-in RAH (Reverse Absorber Heater) is presented. The maximum temperature (50 o C) inside of the methane tank was taken as a main parameter at the design of the digester. Using energy balance equation for the case of a static mass of fluid being heated; the parameters of thermal insulation of the methane tank were counted. The biogas digester is consisting of methane tank with built-in solar RAH to utili...

  15. A high absorbance material for solar collectors' applications

    In this work, we proposed a low cost material to be used as an excellent absorber for solar collectors, to increase its thermal efficiency by the high capacity to absorb solar radiation. The material, known as 'smoke black' (soot) can be obtained by the incomplete combustion of organic materials, such as the oxygen-acetylene, paraffin, or candles. A comparative analysis between the optical properties (reflectance, absorbance, and emissivity) measured on three covered copper surfaces (without paint, with a commercial matte black paint, and with smoke black) shows amazing optical results for the smoke black. Reflectance values of the smoke black applied over copper surfaces improves 56 times the values obtained from commercial black paints. High values of emissivity (E=0.9988) were measured on the surface covered with smoke black by spectrophotometry in the UV-VIS range, which represents about 7% of increment as compared with the value obtained for commercial black paints (E=0.938). The proposed high absorbance material can be easily applied on any kind of surfaces at low cost.

  16. Effect of different absorbing materials on the performance of basin solar still under Libyan climate conditions

    This experimental study deals with a single-basin solar still using various absorbing materials with and without black painting. Different types of absorbing materials with and without black painting were used to enhance the solar still productivity through improvement in absorptivity. These materials are steel and aluminum with and without black painting and rubber. Two identical solar stills were manufactured using locally available materials. All the results were compared together to reach the best absorbing materials with and without painting that can be used for solar still. it was found that the rubber absorber has the highest water collection during daytime, followed by the black painted steel absorber, then by black painted aluminum absorber and steel without painting absorber. The average enhancement in the daily productivity was about 50% for the rubber absorber compared with the black painted aluminum absorber and about 43% for the rubber absorber compared with the black painted steel absorber.(author)

  17. Brown carbon: a significant atmospheric absorber of solar radiation?

    Y. Feng

    2013-09-01

    Full Text Available Several recent observational studies have shown organic carbon aerosols to be a significant source of absorption of solar radiation. The absorbing part of organic aerosols is referred to as "brown" carbon (BrC. Using a global chemical transport model and a radiative transfer model, we estimate for the first time the enhanced absorption of solar radiation due to BrC in a global model. The simulated wavelength dependence of aerosol absorption, as measured by the absorption Ångström exponent (AAE, increases from 0.9 for non-absorbing organic carbon to 1.2 (1.0 for strongly (moderately absorbing BrC. The calculated AAE for the strongly absorbing BrC agrees with AERONET spectral observations at 440–870 nm over most regions but overpredicts for the biomass burning-dominated South America and southern Africa, in which the inclusion of moderately absorbing BrC has better agreement. The resulting aerosol absorption optical depth increases by 18% (3% at 550 nm and 56% (38% at 380 nm for strongly (moderately absorbing BrC. The global simulations suggest that the strongly absorbing BrC contributes up to +0.25 W m−2 or 19% of the absorption by anthropogenic aerosols, while 72% is attributed to black carbon, and 9% is due to sulfate and non-absorbing organic aerosols coated on black carbon. Like black carbon, the absorption of BrC (moderately to strongly inserts a warming effect at the top of the atmosphere (TOA (0.04 to 0.11 W m−2, while the effect at the surface is a reduction (−0.06 to −0.14 W m−2. Inclusion of the strongly absorption of BrC in our model causes the direct radiative forcing (global mean of organic carbon aerosols at the TOA to change from cooling (−0.08 W m−2 to warming (+0.025 W m−2. Over source regions and above clouds, the absorption of BrC is higher and thus can play an important role in photochemistry and the hydrologic cycle.

  18. Solar Biogas Digester with Built-In Reverse Absorber Heater

    Khasan S. Karimov

    2013-01-01

    Full Text Available In this work the design, fabrication and investigation of a solar biogas digester with built-in RAH (Reverse Absorber Heater is presented. The maximum temperature (50 o C inside of the methane tank was taken as a main parameter at the design of the digester. Using energy balance equation for the case of a static mass of fluid being heated; the parameters of thermal insulation of the methane tank were counted. The biogas digester is consisting of methane tank with built-in solar RAH to utilize solar energy for the heating of the slurry prepared from the different organic wastes (dung, sewage, food wastes etc. The methane tank was filled up to 70% of volume by organic wastes of the GIK Institute sewage, firstly, and secondly, by sewage and cow dung as well. During three months (October-December, 2009 and two months (February-March, 2010 the digester was investigated. The solar irradiance incident to the absorber, slurry's temperature and ambient temperature were measured. It was found that using sewage only and sewage with cow dung the retention times was 4 weeks and two weeks respectively and biogas quantity produced was 0.4 and 8.0 m 3 respectively. In addition, biogas upgradation scheme for removal of carbon dioxide, hydrogen sulphide and water vapor from biogas and conversion of biogas energy conversion into electric power is also discussed.

  19. Solar biogas digester with built-in reverse absorber heater

    In this work the design, fabrication and investigation of a solar biogas digester with built-in RAH (Reverse Absorber Heater) is presented. The maximum temperature (50 deg. C) inside of the methane tank was taken as a main parameter at the design of the digester. Using energy balance equation for the case of a static mass of fluid being heated; the parameters of thermal insulation of the methane tank were counted. The biogas digester is consisting of methane tank with built-in solar RAH to utilize solar energy for the heating of the slurry prepared from the different organic wastes (dung, sewage, food wastes etc). The methane tank was filled up to 70% of volume by organic wastes of the GIK Institute sewage, firstly, and secondly, by sewage and cow dung as well. During three months (October-December, 2009) and two months (February-March, 2010) the digester was investigated. The solar irradiance incident to the absorber, slurry's temperature and ambient temperature were measured. It was found that using sewage only and sewage with cow dung the retention times was 4 weeks and two weeks respectively and biogas quantity produced was 0.4 and 8.0 m 3 respectively. In addition, biogas upgradation scheme for removal of carbon dioxide, hydrogen sulphide and water vapor from biogas and conversion of biogas energy conversion into electric power is also discussed. (author)

  20. Spray CVD for Making Solar-Cell Absorber Layers

    Banger, Kulbinder K.; Harris, Jerry; Jin, Michael H.; Hepp, Aloysius

    2007-01-01

    Spray chemical vapor deposition (spray CVD) processes of a special type have been investigated for use in making CuInS2 absorber layers of thin-film solar photovoltaic cells from either of two subclasses of precursor compounds: [(PBu3) 2Cu(SEt)2In(SEt)2] or [(PPh3)2Cu(SEt)2 In(SEt)2]. The CuInS2 films produced in the experiments have been characterized by x-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy, and four-point-probe electrical tests.

  1. Roof Integrated Solar Absorbers: The Measured Performance of ''Invisible'' Solar Collectors: Preprint

    The Florida Solar Energy Center (FSEC), with the support of the National Renewable Energy Laboratory, has investigated the thermal performance of solar absorbers that are an integral, yet indistinguishable, part of a building's roof. The first roof-integrated solar absorber (RISA) system was retrofitted into FSEC's Flexible Roof Facility in Cocoa, Florida, in September 1998. This ''proof-of-concept'' system uses the asphalt shingle roof surface and the plywood decking under the shingles as an unglazed solar absorber. Data was gathered for a one-year period on the system performance. In Phase 2, two more RISA prototypes were constructed and submitted for testing. The first used the asphalt shingles on the roof surface with the tubing mounted on the underside of the plywood decking. The second prototype used metal roofing panels over a plywood substrate and placed the polymer tubing between the plywood decking and the metal roofing. This paper takes a first look at the thermal performance results for the ''invisible'' solar absorbers that use the actual roof surface of a building for solar heat collection

  2. Emitter/absorber interface of CdTe solar cells

    Song, Tao; Kanevce, Ana; Sites, James R.

    2016-06-01

    The performance of CdTe solar cells can be very sensitive to the emitter/absorber interface, especially for high-efficiency cells with high bulk lifetime. Performance losses from acceptor-type interface defects can be significant when interface defect states are located near mid-gap energies. Numerical simulations show that the emitter/absorber band alignment, the emitter doping and thickness, and the defect properties of the interface (i.e., defect density, defect type, and defect energy) can all play significant roles in the interface recombination. In particular, a type I heterojunction with small conduction-band offset (0.1 eV ≤ ΔEC ≤ 0.3 eV) can help maintain good cell efficiency in spite of high interface defect density, much like with Cu(In,Ga)Se2 (CIGS) cells. The basic principle is that positive ΔEC, often referred to as a "spike," creates an absorber inversion and hence a large hole barrier adjacent to the interface. As a result, the electron-hole recombination is suppressed due to an insufficient hole supply at the interface. A large spike (ΔEC ≥ 0.4 eV), however, can impede electron transport and lead to a reduction of photocurrent and fill-factor. In contrast to the spike, a "cliff" (ΔEC CdTe solar cells, but the CdS/CdTe interface is in the cliff category and is not favorable from the band-offset perspective. The ΔEC of other n-type emitter choices, such as (Mg,Zn)O, Cd(S,O), or (Cd,Mg)Te, can be tuned by varying the elemental ratio for an optimal positive value of ΔEC. These materials are predicted to yield higher voltages and would therefore be better candidates for the CdTe-cell emitter.

  3. Solar Multi-stage Refrigeration Systems on the Basis of Absorber with the Internal Evaporative Cooling

    Doroshenko A.V.; Kirillov V.H.; Antonova A.R.; Liudnicky K.V.

    2015-01-01

    In the article, the developed schematics are presented for the alternative refrigeration systems and air-conditioning systems, based on the use of absorbing cycle and solar energy for the regeneration of absorbent solution. Multi-stage principle of construction of drying and cool contours of solar systems is used with growth of concentration of absorbent on the stages of cooler. An absorber with internal evaporative cooling, allowing to remove the separate evaporated cooler, usually included ...

  4. Emitter/absorber interface of CdTe solar cells

    Song, Tao [Physics Department, Colorado State University, Fort Collins, Colorado 80523, USA; Kanevce, Ana [National Renewable Energy Laboratory, Golden, Colorado 80401, USA; Sites, James R. [Physics Department, Colorado State University, Fort Collins, Colorado 80523, USA

    2016-06-17

    The performance of CdTe solar cells can be very sensitive to their emitter/absorber interfaces, especially for high-efficiency cells with improved bulk properties. When interface defect states are located at efficient recombination energies, performance losses from acceptor-type interface defects can be significant. Numerical simulations show that the emitter/absorber band alignment, the emitter doping and thickness, and the defect properties of the interface (i.e. defect density, defect type, and defect energy) can all play significant roles in the interface recombination. In particular, a type I heterojunction with small conduction-band offset (0.1 eV absorber inversion and hence a large hole barrier adjacent to the interface. As a result, the electron-hole recombination is suppressed due to an insufficient hole supply at the interface. A large spike (..delta..EC >/= 0.4 eV), however, can impede electron transport and lead to a reduction of photocurrent and fill-factor. In contrast to the spike, a 'cliff' (.delta..EC < 0 eV) is likely to allow many holes in the vicinity of the interface, which will assist interface recombination and result in a reduced open-circuit voltage. In addition, a thin and highly-doped emitter can invert the absorber, form a large hole barrier, and decrease device performance losses due to high interface defect density. CdS is the most common emitter material used in CdTe solar cells, but the CdS/CdTe interface is in the cliff category and is not favorable from the band-offset perspective. Other n-type emitter choices, such as (Mg,Zn)O, Cd(S,O), or (Cd,Mg)Te, can be tuned by varying the elemental ratio for an optimal positive value of ..delta..EC. These materials are predicted

  5. Improved high temperature solar absorbers for use in Concentrating Solar Power central receiver applications.

    Stechel, Ellen Beth; Ambrosini, Andrea; Hall, Aaron Christopher; Lambert, Timothy L.; Staiger, Chad Lynn; Bencomo, Marlene

    2010-09-01

    Concentrating solar power (CSP) systems use solar absorbers to convert the heat from sunlight to electric power. Increased operating temperatures are necessary to lower the cost of solar-generated electricity by improving efficiencies and reducing thermal energy storage costs. Durable new materials are needed to cope with operating temperatures >600 C. The current coating technology (Pyromark High Temperature paint) has a solar absorptance in excess of 0.95 but a thermal emittance greater than 0.8, which results in large thermal losses at high temperatures. In addition, because solar receivers operate in air, these coatings have long term stability issues that add to the operating costs of CSP facilities. Ideal absorbers must have high solar absorptance (>0.95) and low thermal emittance (<0.05) in the IR region, be stable in air, and be low-cost and readily manufacturable. We propose to utilize solution-based synthesis techniques to prepare intrinsic absorbers for use in central receiver applications.

  6. Development of optical tool for the characterization of selective solar absorber tubes

    Braillon, Julien; Stollo, Alessio; Delord, Christine; Raccurt, Olivier

    2016-05-01

    In the Concentrated Solar Power (CSP) technologies, selective solar absorbers, which have a cylindrical geometry, are submitted to strong environmental constraints. The degradation of their optical properties (total solar absorbance and total emittance) has a direct impact on the performances. In order to know optical properties of absorber tubes, we present in this article a new optical tool developed by our laboratory which fit onto commercial spectrometers. Total solar absorbance and total emittance are calculated from total reflectance spectra measured by UV-Vis and IR spectrophotometry. To verify and validate the measurement method, we performed a comparative study between flat and cylindrical samples with same surface properties.

  7. Large-Scale Nanophotonic Solar Selective Absorbers for High-Efficiency Solar Thermal Energy Conversion.

    Li, Pengfei; Liu, Baoan; Ni, Yizhou; Liew, Kaiyang Kevin; Sze, Jeff; Chen, Shuo; Shen, Sheng

    2015-08-19

    An omnidirectional nanophotonic solar selective absorber is fabricated on a large scale using a template-stripping method. The nanopyramid nickel structure achieves an average absorptance of 95% at a wavelength range below 1.3 μm and a low emittance less than 10% at wavelength >2.5 μm. PMID:26134928

  8. Thermal performance of linear Fresnel reflecting solar concentrator with trapezoidal cavity absorbers

    Thermal performance of the four identical trapezoidal cavity absorbers for linear Fresnel reflecting solar device were studied and compared. The absorbers were designed for operating in conjunction with a prototype Fresnel solar reflector. Rectangular and round pipe sections were used as absorber by placing in the trapezoidal cavity. The absorber pipes were coated with ordinary dull black board paint and black nickel selective surface. The bottom of the cavity was provided with plane glass to allow the solar radiation to be reflected from the Fresnel reflector. The other three sides of the cavity absorber were insulated to reduce heat loss. Thermal performance of the Fresnel reflecting concentrator with each trapezoidal cavity absorber was studied experimentally at different concentration ratio of the reflector. The study revealed that the thermal efficiency was influenced by the concentration ratio and selective surface coating on the absorber. The thermal efficiency decreased with the increase in the concentration ratio of the Fresnel reflecting collector. The selective surface coated absorber had a significant advantage in terms of superior thermal performance as compared to ordinary black painted absorber. The round pipe (multi-tube) receiver had higher surface area to absorb solar energy as compared to rectangular pipe receiver. Thermal efficiency of the solar device with round pipe absorber was found higher (up to 8%) as compared to rectangular pipe absorber.

  9. Brown carbon: a significant atmospheric absorber of solar radiation?

    Y. Feng

    2013-01-01

    Full Text Available Several recent observational studies have shown organic carbon aerosols to be a significant source of absorption of solar radiation. The absorbing part of organic aerosols is referred to as brown carbon. Comparisons with observations indicate that model-simulated aerosol absorption is under-estimated in global models, one of the reasons being the neglect of brown carbon. Using a global chemical transport model coupled with a radiative transfer model, we estimate for the first time the enhanced absorption of solar radiation due to "brown" carbon (BrC in a global model. When BrC is included, the simulated wavelength dependence of aerosol absorption, as measured by the Angstrom exponent increases from 0.9 to 1.2 and thus agrees better with AERONET spectral observations at 440–870 nm. The resulting absorbing aerosol optical depth increases by 3–18% at 550 nm and up to 56% at 350 nm. The global simulations suggest that BrC contributes up to +0.25 W m−2 or 19% of the absorption by anthropogenic aerosols, of which 72% is attributed to black carbon, and 9% is due to sulfate and non-absorbing organic aerosols coated on black carbon. Like black carbon, the overall forcing of BrC at the top of the atmosphere (TOA is a warming effect (+0.11 W m−2, while the effect at the surface is a reduction or dimming (−0.14 W m−2. Because of the inclusion of BrC in our model, the direct radiative effect of organic carbonaceous aerosols changes from cooling (−0.08 W m−2 to warming (+0.025 W m−2 at the TOA, on a global mean basis. Over source regions and above clouds, the absorption of BrC is more significant and thus can play an important role in photochemistry and the hydrologic cycle.

  10. Thermal performance of integrated collector storage solar water heater with corrugated absorber surface

    An investigation is reported of the thermal performance of an integrated solar water heater with a corrugated absorber surface. The thermal performance of the rectangular collector/storage solar water heater depends significantly on the heat transfer rate between the absorber surface and the water, and on the amount of solar radiation incident on the absorber surface. In this investigation, the surface of the absorber is considered to be corrugated, with small indentation depths, instead of plane. The modified surface has a higher characteristic length for convective heat transfer from the absorber to the water, in addition to having more surface area exposed to solar radiation. The corrugated surface based solar water heater is determined to have a higher operating temperature for longer time than the plane surface. It means during the operation of water heater, more solar energy is converted into useful heat. However, this modification has reduces the efficiency of the system marginally.

  11. Optimal Design of V-shaped Absorber Plate to the Performance of Solar Water Heater

    Jalaluddin

    2014-01-01

    Solar energy is known as an environmentally friendly energy source and wide range of applications. This energy is utilized in various applications such as domestic and industrial water heating, refrigeration, cooking, power production and water pumping etc. The present study analyzes absorptivity of flat-plate absorber and various V-shaped absorber plates. Analytical investigation of absorptivity of the various V-shaped absorber plates and comparison with that of the flat-plate absorber was c...

  12. Optimization of spectrally-selective coatings for solar absorbers

    Orel, Z.C.; Gunde, M.K. [National Inst. of Chemistry, Ljubljana (Slovenia)

    2000-07-01

    The inexpensive selective surfaces for solar absorbers were prepared by application of black paint on the high-reflective substrate. The layers have to be transparent in the infrared in order to support the low thermal emittance of the substrate. For this purpose, the optical properties of coatings have to be optimized to minimize the expense of the final product. The selectivity was attained by the mutual effect of a highly absorptive black paint layer and low emitting (i.e., infrared reflecting) metal substrate. Optimized paint coatings are not thicker than a few micrometers and exhibit high opacity, leading to energy-efficient selective coatings for solar collector applications. The painted samples are characterized by high absorption, finite sample thickness, nonideal support material, and smooth front surface. These properties distinguish our samples from those of other studies in this field. To design a functional pigmented layer, the optical properties of all constituents have to be known separately. Due to this reason the diffuse reflectance of black thickness-sensitive spectrally selective (TSSS) paints was analyzed. For theoretical consideration of paint layers, the simple Kubelka-Munk (KM) theory was used. It is the almost universally applied theoretical approach within the color using industry (1). It relates diffuse reflectance of a pigmented layer to two phenomenological coefficients, absorption (K) and scattering (S), thickness of the layer, and reflectance of the substrate. The optical properties of layer material are involved in both coefficients. This enables optimal thickness calculation (2), i.e. the theoretical prediction of the best thickness value that will give the highest solar absorptance and simultaneously, the lowest thermal emittance of the respective paint. The KM coefficients depend also upon addition of fumed silica (dispersive agent). Applying KM theory, the degree of pigment dispersion was quantified (3). This approach was an

  13. Electrochemical deposition of black nickel solar absorber coatings on stainless steel AISI316L for thermal solar cells

    Lira-Cantú, Monica; Morales Sabio, Angel; Brustenga, Alex; Gómez-Romero, P.

    2005-01-01

    We report the electrochemical deposition of nanostructured nickel-based solar absorber coatings on stainless steel AISI type 316L. A sol–gel silica-based antireflection coating, from TEOS, was also applied to the solar surface by the dip-coating method. We report our initial results and analyze the influence of the stainless steel substrate on the final total reflectance properties of the solar absorber. The relation between surface morphology, observed by SEM and AFM, the comp...

  14. Highly-Efficient Selective Metamaterial Absorber for High-Temperature Solar Thermal Energy Harvesting

    Wang, Hao; Sivan, Vijay Prasad; Mitchell, Arnan; Rosengarten, Gary; Phelan, Patrick; Wang, Liping

    2014-01-01

    In this work, a metamaterial selective solar absorber made of nanostructured titanium gratings deposited on an ultrathin MgF2 spacer and a tungsten ground film is proposed and experimentally demonstrated. Normal absorptance of the fabricated solar absorber is characterized to be higher than 90% in the UV, visible and, near infrared (IR) regime, while the mid-IR emittance is around 20%. The high broadband absorption in the solar spectrum is realized by the excitation of surface plasmon and mag...

  15. Development of a Solar Assisted Drying System Using Double-Pass Solar Collector with Finned Absorber

    The Solar Energy Research Group, Universiti Kebangsaan Malaysia, International Islamic University Malaysia and Yayasan FELDA has designed and constructed a solar assisted drying system at OPF FELDA Factory, Felda Bukit Sagu 2, Kuantan, Pahang. The drying system has a total of six double-pass solar collectors. Each collector has a length of 480 cm and a width of 120 cm. The first channel depth is 3.5 cm and the second channel depth is 7 cm. Longitudinal fins made of angle aluminium, 0.8 mm thickness were attached to the bottom surface of the absorber plate. The solar collectors are arranged as two banks of three collectors each in series. Internal manifold are used to connect the collectors. Air enters through the first channel and then through the second channel of the collector. An auxiliary heater source is installed to supply heat under unfavourable solar radiation condition. An on/off controller is used to control the startup and shutdown of the auxiliary heater. An outlet temperature of 70–75 °C can be achieved at solar radiation range of 800–900 W/m2 and flow rate of 0.12 kg/s. The average thermal efficiency of a solar collector is approximately 37%.

  16. Development of a Solar Assisted Drying System Using Double-Pass Solar Collector with Finned Absorber

    Azmi, M. S. M.; Othman, M. Y.; Sopian, K.; Ruslan, M. H.; Majid, Z. A. A.; Fudholi, A.; Yasin, J. M.

    2012-09-01

    The Solar Energy Research Group, Universiti Kebangsaan Malaysia, International Islamic University Malaysia and Yayasan FELDA has designed and constructed a solar assisted drying system at OPF FELDA Factory, Felda Bukit Sagu 2, Kuantan, Pahang. The drying system has a total of six double-pass solar collectors. Each collector has a length of 480 cm and a width of 120 cm. The first channel depth is 3.5 cm and the second channel depth is 7 cm. Longitudinal fins made of angle aluminium, 0.8 mm thickness were attached to the bottom surface of the absorber plate. The solar collectors are arranged as two banks of three collectors each in series. Internal manifold are used to connect the collectors. Air enters through the first channel and then through the second channel of the collector. An auxiliary heater source is installed to supply heat under unfavourable solar radiation condition. An on/off controller is used to control the startup and shutdown of the auxiliary heater. An outlet temperature of 70-75 °C can be achieved at solar radiation range of 800-900 W/m2 and flow rate of 0.12 kg/s. The average thermal efficiency of a solar collector is approximately 37%.

  17. Corrosion protection of PVD and paint coatings for selective solar absorber surfaces

    Nunes, A.; Carvalho, M. J.; Diamantino, Teresa C.; Fernandes, J. C. S.

    2015-01-01

    The selective solar absorber surface is a fundamental part of a solar thermal collector, as it is responsible for the solar radiation absorption and for reduction of radiation heat losses. The surface’s optical properties, the solar absorption (á) and the emittance (å), have great impact on the solar thermal collector efficiency. In this work, two coatings types were studied: coatings obtained by physical vapor deposition (PVDs) and coatings obtained by projection with different paints (PCs) ...

  18. Flow distribution in a solar collector panel with horizontally inclined absorber strips

    Fan, Jianhua; Shah, Louise Jivan; Furbo, Simon

    2007-01-01

    The objective of this work is to theoretically and experimentally investigate the flow and temperature distribution in a solar collector panel with an absorber consisting of horizontally inclined strips. Fluid flow and heat transfer in the collector panel are studied by means of computational fluid...... dynamics (CFD) calculations. Further, experimental investigations of a 12.5 m(2) solar collector panel with 16 parallel connected horizontal fins are carried out. The flow distribution through the absorber is evaluated by means of temperature measurements on the backside of the absorber tubes. The measured...... rate, properties of solar collector fluid, solar collector fluid inlet temperature and collector tilt angle are shown. The flow distribution through the absorber fins is uniform if high flow rates are used. By decreased flow rate and decreased content of glycol in the glycol/water mixture used as solar...

  19. Thermal performance of a novel linear cavity absorber for parabolic trough solar concentrator

    Highlights: • Optimized cavity absorber with heat transfer enhancement design. • Cavity absorber was used for conventional materials and fabrication techniques. • Model on thermal of cavity absorber was established. • Thermal efficiency of the cavity were discussed by analysis and experiment. - Abstract: A novel linear cavity absorber for parabolic trough solar concentrator (PTC) was designed in the present study. The cavity absorber was used for conventional fabrication techniques and its thermal performance was carried out. The theoretical model of thermal efficiency for the cavity absorber has been established and verified by the experimental results. The results revealed that there was an agreement between the model and experiment. Furthermore, the temperature of the working fluid could reach 570 K, and the thermal efficiency of the cavity absorber was comparable to that of evacuated tube when the temperature of working fluid was in medium temperature. In conclusion, the thermal performance for the cavity absorber with glass cover and fins was improved

  20. Photochromic And Thermochromic Pigments For Solar Absorbing-Reflecting Coatings

    Novinson, Thomas

    1987-11-01

    Both photochromic and thermochromic compounds were synthesized and physical measurements were made to determine coefficients of relectance, absorbance and emission. The most interesting group of thermochromic compounds are related to silver tctraiodomercurate and the most interesting photochromic compounds are substituted benzoindolinopyrospirans. The synthesis and optical reflectance and absorbance properties of other classes of compounds are also reported.

  1. Development of optical tools for the characterization of selective solar absorber at elevated temperature

    Giraud, Philemon; Braillon, Julien; Delord, Christine; Raccurt, Olivier

    2016-05-01

    Durability of solar components for CSP (Concentrated Solar Power Plant) technologies is a key point to lower cost and ensure their large deployment. These technologies concentrated the solar radiation by means of mirrors on a receiver tube where it is collected as thermal energy. The absorbers are submitted to strong environmental constraints and the degradation of their optical properties (emittance and solar absorbance) have a direct impact on performance. The objective is to develop new optical equipment for characterization of this solar absorber in condition of use that is to say in air and at elevated temperature. In this paper we present two new optical test benches developed for optical characterization of solar absorbers in condition of use up to 800°C. The first equipment is an integrated sphere with heated sample holder which measures the hemispherical reflectance between 280 and 2500 nm to calculate the solar absorbance at high temperature. The second optical test bench measures the emittance of samples up to 1000°C in the range of 1.25 to 28.57 µm. Results of high temperature measurements on a series of metallic absorbers with selective coating and refractory material for high thermal receiver are presented.

  2. Solar Multi-stage Refrigeration Systems on the Basis of Absorber with the Internal Evaporative Cooling

    Doroshenko A.V.

    2015-08-01

    Full Text Available In the article, the developed schematics are presented for the alternative refrigeration systems and air-conditioning systems, based on the use of absorbing cycle and solar energy for the regeneration of absorbent solution. Multi-stage principle of construction of drying and cool contours of solar systems is used with growth of concentration of absorbent on the stages of cooler. An absorber with internal evaporative cooling, allowing to remove the separate evaporated cooler, usually included after the absorber of the proper stage, is developed. Heat-mass-transfer apparatus of film-type, entering in the complement of drying and cool contours compatible and executed on the basis of multichannel compositions from polymeric materials. The preliminary comparative analysis of possibilities of the solar refrigeration systems and air-conditioning systems is executed.

  3. Experimental investigations of the performance of a solar air collector with latent heat thermal storage integrated with the solar absorber

    Hejcik J.; Pech O.; Charvat P.

    2013-01-01

    The paper deals with experimental investigations of the performance of a solar air collector with latent heat thermal storage integrated with the solarabsorber. The main purpose of heat storage in solar thermal systems is to store heat when the supply of solar heat exceeds demand and release it when otherwise. A number of heat storage materials can be used for this purpose; the phase change materials among them. Short-term latent heat thermal storage integrated with the solar absorber can sta...

  4. Radiative cooling of solar absorbers using a visibly transparent photonic crystal thermal blackbody.

    Zhu, Linxiao; Raman, Aaswath P; Fan, Shanhui

    2015-10-01

    A solar absorber, under the sun, is heated up by sunlight. In many applications, including solar cells and outdoor structures, the absorption of sunlight is intrinsic for either operational or aesthetic considerations, but the resulting heating is undesirable. Because a solar absorber by necessity faces the sky, it also naturally has radiative access to the coldness of the universe. Therefore, in these applications it would be very attractive to directly use the sky as a heat sink while preserving solar absorption properties. Here we experimentally demonstrate a visibly transparent thermal blackbody, based on a silica photonic crystal. When placed on a silicon absorber under sunlight, such a blackbody preserves or even slightly enhances sunlight absorption, but reduces the temperature of the underlying silicon absorber by as much as 13 °C due to radiative cooling. Our work shows that the concept of radiative cooling can be used in combination with the utilization of sunlight, enabling new technological capabilities. PMID:26392542

  5. Enhanced Thermal Stability of W-Ni-Al[subscript 2]O[subscript 3] Cermet-Based Spectrally Selective Solar Absorbers with Tungsten Infrared Reflectors

    Cao, Feng; Kraemer, Daniel; Sun, Tianyi; Lan, Yucheng; Chen, Gang; Ren, Zhifeng

    2014-01-01

    Solar thermal technologies such as solar hot water and concentrated solar power trough systems rely on spectrally selective solar absorbers. These solar absorbers are designed to efficiently absorb the sunlight while suppressing re-emission of infrared radiation at elevated temperatures. Efforts for the development of such solar absorbers must not only be devoted to their spectral selectivity but also to their thermal stability for high temperature applications. Here, selective solar absorber...

  6. SOLAR REFRIGERATION SYSTEMS BASED ON THE ABSORBER WITH INTERNAL EVAPORATIVE COOLING

    Дорошенко, O.В.; Людницький, К.В.

    2015-01-01

    The paper presents the developed schematics for alternative refrigeration systems and air conditioning systems based on the use of heat-absorption cycle and solar energy for regeneration (recovery) of the absorbent solution. Cascade principle of construction of the drying and cooling circuits with absorbent concentration increasing on the steps of the cascade is used. The absorber with internal evaporative cooling that eliminates a separate evaporative cooler, typically comprised after the co...

  7. Comparison of silicon oxide and silicon carbide absorber materials in silicon thin-film solar cells

    Walder Cordula; Kellermann Martin; Wendler Elke; Rensberg Jura; von Maydell Karsten; Agert Carsten

    2015-01-01

    Since solar energy conversion by photovoltaics is most efficient for photon energies at the bandgap of the absorbing material the idea of combining absorber layers with different bandgaps in a multijunction cell has become popular. In silicon thin-film photovoltaics a multijunction stack with more than two subcells requires a high bandgap amorphous silicon alloy top cell absorber to achieve an optimal bandgap combination. We address the question whether amorphous silicon carbide (a-SiC:H) or ...

  8. Self-assembly of highly efficient, broadband plasmonic absorbers for solar steam generation

    Zhou, Lin; Tan, Yingling; Ji, Dengxin; Zhu, Bin; Zhang, Pei; Xu, Jun; Gan, Qiaoqiang; Yu, Zongfu; Zhu, Jia

    2016-01-01

    The study of ideal absorbers, which can efficiently absorb light over a broad range of wavelengths, is of fundamental importance, as well as critical for many applications from solar steam generation and thermophotovoltaics to light/thermal detectors. As a result of recent advances in plasmonics, plasmonic absorbers have attracted a lot of attention. However, the performance and scalability of these absorbers, predominantly fabricated by the top-down approach, need to be further improved to enable widespread applications. We report a plasmonic absorber which can enable an average measured absorbance of ~99% across the wavelengths from 400 nm to 10 μm, the most efficient and broadband plasmonic absorber reported to date. The absorber is fabricated through self-assembly of metallic nanoparticles onto a nanoporous template by a one-step deposition process. Because of its efficient light absorption, strong field enhancement, and porous structures, which together enable not only efficient solar absorption but also significant local heating and continuous stream flow, plasmonic absorber–based solar steam generation has over 90% efficiency under solar irradiation of only 4-sun intensity (4 kW m−2). The pronounced light absorption effect coupled with the high-throughput self-assembly process could lead toward large-scale manufacturing of other nanophotonic structures and devices.

  9. PROCESSES OF HEAT-MASS-TRANSFER IN APPARATUS OF SOLAR ABSORBING REFRIGERATION SYSTEMS

    Doroshenko A.V.; Ludnitsky K.V.

    2014-01-01

    Ideology of development of the solar refrigeration systems and systems of air-conditioning, based on the use of absorbing cycle and solar energy for the regeneration of absorbent solution, is presented in the article. The processes of joint heat-mass-transfer are considered in the direct and indirect types of evaporated coolers taking into account the phenomenon of re-condensation of aquatic steams at the low temperature evaporated cooling of environments. The pre-liminary analysis of possibi...

  10. FLOW DISTRIBUTION IN A SOLAR COLLECTOR PANEL WITH HORIZONTAL ABSORBER STRIPS

    Fan, Jianhua; Shah, Louise Jivan; Furbo, Simon

    2007-01-01

    The objective of this work is to theoretically and experimentally investigate the flow and temperature distribution in a solar collector panel with an absorber consisting of horizontal strips. Fluid flow and heat transfer in the collector panel are studied by means of computational fluid dynamics (CFD) calculations. Further, experimental investigations of a 12.5 m² solar collector panel with 16 parallel connected horizontal fins are carried out. The flow distribution through the absorber is e...

  11. performance Analysis of Different Energy Absorbing Plates on Solar Stills

    H.N. Panchal

    2011-12-01

    Full Text Available Solar distillation mimics nature’s hydrologic water cycle by purify water through evaporation as well as condensation. It is one of the most basic purification systems available today to get high quality of drinking water and can remove non-volatile contamination from almost any water source. Solar still is a one kind of solar distillation system in which brackish or impure water converted into drinkable water. Here, three solar stills have developed by locally available materials. The first one is a conventional type and the second solar still is consists of Aluminum plate while the third one consists of Galvanized iron. Here, experiment performed to get higher distillate output from solar still. Experiments represent that, solar still consists of aluminum plate gives 30 % more output compared with conventional solar still and Galvanized iron plate inside solar still gives 12% more output compared with conventional solar still. Hence, Aluminum plate is the best plate to obtain higher distillate output from solar still.

  12. Removal of fluorescence and ultraviolet absorbance of dissolved organic matter in reclaimed water by solar light.

    Wu, Qianyuan; Li, Chao; Wang, Wenlong; He, Tao; Hu, Hongying; Du, Ye; Wang, Ting

    2016-05-01

    Storing reclaimed water in lakes is a widely used method of accommodating changes in the consumption of reclaimed water during wastewater reclamation and reuse. Solar light serves as an important function in degrading pollutants during storage, and its effect on dissolved organic matter (DOM) was investigated in this study. Solar light significantly decreased the UV254 absorbance and fluorescence (FLU) intensity of reclaimed water. However, its effect on the dissolved organic carbon (DOC) value of reclaimed water was very limited. The decrease in the UV254 absorbance intensity and FLU excitation-emission matrix regional integration volume (FLU volume) of reclaimed water during solar light irradiation was fit with pseudo-first order reaction kinetics. The decrease of UV254 absorbance was much slower than that of the FLU volume. Ultraviolet light in solar light had a key role in decreasing the UV254 absorbance and FLU intensity during solar light irradiation. The light fluence-based removal kinetic constants of the UV254 and FLU intensity were independent of light intensity. The peaks of the UV254 absorbance and FLU intensity with an apparent molecular weight (AMW) of 100Da to 2000Da decreased after solar irradiation, whereas the DOC value of the major peaks did not significantly change. PMID:27155416

  13. PROCESSES OF HEAT-MASS-TRANSFER IN APPARATUS OF SOLAR ABSORBING REFRIGERATION SYSTEMS

    Doroshenko A.V.

    2014-12-01

    Full Text Available Ideology of development of the solar refrigeration systems and systems of air-conditioning, based on the use of absorbing cycle and solar energy for the regeneration of absorbent solution, is presented in the article. The processes of joint heat-mass-transfer are considered in the direct and indirect types of evaporated coolers taking into account the phenomenon of re-condensation of aquatic steams at the low temperature evaporated cooling of environments. The pre-liminary analysis of possibilities of the solar systems is executed as it applies in relation to the tasks of cooling of envi-ronments and air-conditioning systems.

  14. Estimating Solar Irradiation Absorbed by Photovoltaic Panels with Low Concentration Located in Craiova, Romania

    Ionel L. Alboteanu

    2015-03-01

    Full Text Available Solar irradiation is one of the important parameters that should be taken into consideration for the design and utilization of a photovoltaic system. Usually, the input parameters of a photovoltaic system are solar irradiation, the ambient environment temperature and the wind speed, and as a consequence most photovoltaic systems are equipped with sensors for measuring these parameters. This paper presents several mathematical models for solar irradiation assessment. The starting point is represented by the mathematical model of extraterrestrial irradiation, and resulting finally in the model for solar irradiation, absorbed by a low concentration photovoltaic panel. These estimating models of solar irradiation have been particularized for the Craiova, Romania, and have been verified through numerical simulation. Regarding terrestrial solar irradiation, four mathematical models have been adopted, namely Adnot, Haurwitz, Kasten and Empirical (EIM. Of these, the most appropriate for the Craiova location were the models Adnot and Empirical. Consequently, for the calculation of the solar irradiation absorbed by the photovoltaic (PV panels with low concentration, these models have been taken into consideration. In this study, a comparative analysis was also carried out with respect to the solar irradiation absorbed by the PV panels without concentration and those with collectedness of the solar radiation. This analysis was based on the results of numerical simulation and experimental tests.

  15. Improved Single-Source Precursors for Solar-Cell Absorbers

    Banger, Kulbinder K.; Harris, Jerry; Hepp, Aloysius

    2007-01-01

    Improved single-source precursor compounds have been invented for use in spray chemical vapor deposition (spray CVD) of chalcopyrite semiconductor absorber layers of thin-film cells. A "single-source precursor compound" is a single molecular compound that contains all the required elements, which when used under the spray CVD conditions, thermally decomposes to form CuIn(x)Ga(1-x)S(y)Se(2-y).

  16. Multifunctional Solar Systems Based On Two-Stage Regeneration Absorbent Solution

    Doroshenko A.V.

    2015-04-01

    Full Text Available The concepts of multifunctional dehumidification solar systems, heat supply, cooling, and air conditioning based on the open absorption cycle with direct absorbent regeneration developed. The solar systems based on preliminary drainage of current of air and subsequent evaporated cooling. The solar system using evaporative coolers both types (direct and indirect. The principle of two-stage regeneration of absorbent used in the solar systems, it used as the basis of liquid and gas-liquid solar collectors. The main principle solutions are designed for the new generation of gas-liquid solar collectors. Analysis of the heat losses in the gas-liquid solar collectors, due to the mechanism of convection and radiation is made. Optimal cost of gas and liquid, as well as the basic dimensions and configuration of the working channel of the solar collector identified. Heat and mass transfer devices, belonging to the evaporative cooling system based on the interaction between the film and the gas stream and the liquid therein. Multichannel structure of the polymeric materials used to create the tip. Evaporative coolers of water and air both types (direct and indirect are used in the cooling of the solar systems. Preliminary analysis of the possibilities of multifunctional solar absorption systems made reference to problems of cooling media and air conditioning on the basis of experimental data the authors. Designed solar systems feature low power consumption and environmental friendliness.

  17. FLOW DISTRIBUTION IN A SOLAR COLLECTOR PANEL WITH HORIZONTAL ABSORBER STRIPS

    Fan, Jianhua; Shah, Louise Jivan; Furbo, Simon

    2007-01-01

    The objective of this work is to theoretically and experimentally investigate the flow and temperature distribution in a solar collector panel with an absorber consisting of horizontal strips. Fluid flow and heat transfer in the collector panel are studied by means of computational fluid dynamics...... (CFD) calculations. Further, experimental investigations of a 12.5 m² solar collector panel with 16 parallel connected horizontal fins are carried out. The flow distribution through the absorber is evaluated by means of temperature measurements on the backside of the absorber tubes. The measured...... collector fluid, and by increased collector tilt and inlet temperature, the flow distribution gets worse resulting in a decreased collector efficiency and an increased risk of boiling in the upper part of the collector panel. Keywords: Solar collector; Flow distribution; Computational Fluid Dynamics (CFD...

  18. Computational design for a wide-angle cermet-based solar selective absorber for high temperature applications

    The purpose of this study is to computationally design a wide-angle cermet-based solar selective absorber for high temperature applications by using a characteristic matrix method and a genetic algorithm. The present study investigates a solar selective absorber with tungsten–silica (W–SiO2) cermet. Multilayer structures of 1, 2, 3, and 4 layers and a wide range of metal volume fractions are optimized. The predicted radiative properties show good solar performance, i.e., thermal emittances, especially beyond 2 μm, are quite low, in contrast, solar absorptance levels are successfully high with wide angular range, so that solar photons are effectively absorbed and infrared radiative heat loss can be decreased. -- Highlights: • Electromagnetic simulation of radiative properties by characteristic matrix method. • Optimization for multilayered W–SiO2 cermet-based absorber by a Genetic Algorithm. • We propose a successfully high solar performance of solar selective absorber

  19. Experimental investigation of a nanofluid absorber employed in a low-profile, concentrated solar thermal collector

    Li, Qiyuan; Zheng, Cheng; Mesgari, Sara; Hewakuruppu, Yasitha L.; Hjerrild, Natasha; Crisostomo, Felipe; Morrison, Karl; Woffenden, Albert; Rosengarten, Gary; Scott, Jason A.; Taylor, Robert A.

    2015-12-01

    Recent studies [1-3] have demonstrated that nanotechnology, in the form of nanoparticles suspended in water and organic liquids, can be employed to enhance solar collection via direct volumetric absorbers. However, current nanofluid solar collector experimental studies are either relevant to low-temperature flat plate solar collectors (100 °C) indoor laboratory-scale concentrating solar collectors [1, 5]. Moreover, many of these studies involve in thermal properties of nanofluid (such as thermal conductivity) enhancement in solar collectors by using conventional selective coated steel/copper tube receivers [6], and no full-scale concentrating collector has been tested at outdoor condition by employing nanofluid absorber [2, 6]. Thus, there is a need of experimental researches to evaluate the exact performance of full-scale concentrating solar collector by employing nanofluids absorber at outdoor condition. As reported previously [7-9], a low profile (solar thermal concentrating collector was designed and analysed which can potentially supply thermal energy in the 100-250 °C range (an application currently met by gas and electricity). The present study focuses on the design and experimental investigation of a nanofluid absorber employed in this newly designed collector. The nanofluid absorber consists of glass tubes used to contain chemically functionalized multi-walled carbon nanotubes (MWCNTs) dispersed in DI water. MWCNTs (average diameter of 6-13 nm and average length of 2.5-20 μm) were functionalized by potassium persulfate as an oxidant. The nanofluids were prepared with a MCWNT concentration of 50 +/- 0.1 mg/L to form a balance between solar absorption depth and viscosity (e.g. pumping power). Moreover, experimentally comparison of the thermal efficiency between two receivers (a black chrome-coated copper tube versus a MWCNT nanofluid contained within a glass tubetube) is investigated. Thermal experimentation reveals that while the collector efficiency

  20. Global response to solar radiation absorbed by phytoplankton in a coupled climate model

    Patara, L.; CMCC; Vichi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Masina, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Fogli, P. G.; CMCC; Manzini, E.; MPI, Hamburg

    2012-01-01

    The global climate response to solar radiation absorbed by phytoplankton is investigated by performing multi-century simulations with a coupled ocean–atmosphere-biogeochemistry model. The absorption of solar radiation by phytoplankton increases radiative heating in the near-surface ocean and raises sea surface temperature (SST) by overall ~0.5°C. The resulting increase in evaporation enhances specific atmospheric humidity by 2–5%, thereby increasing the Earth’s greenhouse effect and the atmos...

  1. Photovoltaic characterization of Copper-Indium-Gallium Sulfide (CIGS2) solar cells for lower absorber thicknesses

    Vasekar, Parag S., E-mail: psvasekar@yahoo.co [Florida Solar Energy Center, 1679 Clearlake Rd., Cocoa FL, 32922 (United States); Jahagirdar, Anant H.; Dhere, Neelkanth G. [Florida Solar Energy Center, 1679 Clearlake Rd., Cocoa FL, 32922 (United States)

    2010-01-31

    Chalcopyrites are important contenders among thin-film solar cells due to their direct band gap and higher absorption coefficient. Copper-Indium-Gallium Sulfide (CIGS2) is a chalcopyrite material with a near-optimum band gap of {approx} 1.5 eV. Record efficiency of 11.99% has been achieved on a 2.7 {mu}m CIGS2 film prepared by sulfurization at the Florida Solar Energy Center (FSEC) PV Materials Lab. In this work, photovoltaic performance analysis has been carried out for a 1.5 {mu}m absorber prepared under similar conditions as that of a 2.7 {mu}m thick absorber sample. It was observed that there is an increase in diode factor and reverse saturation current density when the absorber thickness was decreased. The diode factor increased from 1.69 to 2.18 and reverse saturation current density increased from 1.04 x 10{sup -10} mA/cm{sup 2} to 1.78 x 10{sup -8} mA/cm{sup 2}. This can be attributed to a decrease in the grain size when the absorber thickness is decreased. It was also observed that there is an improvement in the shunt resistance. Improvement in shunt resistance can be attributed to optimized value of i:ZnO for lower absorber thickness and less shunting paths due to a smoother absorber.

  2. Photovoltaic characterization of Copper-Indium-Gallium Sulfide (CIGS2) solar cells for lower absorber thicknesses

    Chalcopyrites are important contenders among thin-film solar cells due to their direct band gap and higher absorption coefficient. Copper-Indium-Gallium Sulfide (CIGS2) is a chalcopyrite material with a near-optimum band gap of ∼ 1.5 eV. Record efficiency of 11.99% has been achieved on a 2.7 μm CIGS2 film prepared by sulfurization at the Florida Solar Energy Center (FSEC) PV Materials Lab. In this work, photovoltaic performance analysis has been carried out for a 1.5 μm absorber prepared under similar conditions as that of a 2.7 μm thick absorber sample. It was observed that there is an increase in diode factor and reverse saturation current density when the absorber thickness was decreased. The diode factor increased from 1.69 to 2.18 and reverse saturation current density increased from 1.04 x 10-10 mA/cm2 to 1.78 x 10-8 mA/cm2. This can be attributed to a decrease in the grain size when the absorber thickness is decreased. It was also observed that there is an improvement in the shunt resistance. Improvement in shunt resistance can be attributed to optimized value of i:ZnO for lower absorber thickness and less shunting paths due to a smoother absorber.

  3. Synthesis and properties of polyamide–Ag2S composite based solar energy absorber surfaces

    Krylovaa, Valentina; Baltrusaitis, Jonas

    2013-01-01

    Silver sulfide (Ag2S), an efficient solar light absorber, was synthesized using a modified chemical bath deposition (CBD) method and polyamide 6 (PA) as a host material via solution phase reaction between AgNO3 and Na2S2O3. X-ray diffraction (XRD) data showed a single, α-Ag2S (acanthite), crystallin

  4. Experimental Evaluation Of A Single-basin Solar Still Using Different Absorbing Materials: An Overview

    T.R.TELTUMBADE,

    2011-04-01

    Full Text Available Single-basin solar stills can be used for water desalination. Probably, the are considered the best solution for water production in remote,arid to semi-arid, small communities, where fresh water isunavailable.however,the amount of distilled water produced per unit area is somewhat low which makes the single-basin solar still unacceptable in some instances. The purpose of this paper is to study the effect of using different absorbing materials in a solar still, and thuds enhance the productivity of water. Experimental result show that the productivity of distilled water was enhance for some matereals.

  5. New Design of Potentially Low-cost Solar Cells Using TiO2/Graphite Composite as Photon Absorber

    Rahman, Dui Yanto; Rokhmat, Mamat; Yuliza, Elfi; Sustini, Euis; Abdullah, Mikrajuddin

    2015-01-01

    A solar cell design using the combination of titanium dioxide and graphite as active photon absorbing materials were proposed. The titanium dioxide absorbs photons of nearly ultraviolet wavelengths to produce electron hole pairs, while graphite is expected to absorb photons of longer wavelengths. Although many authors have claimed that graphite is not a semiconductor, we observed that a model of a solar cell containing titanium dioxide only as the active material behaves exactly the same as a...

  6. Bifacial solar cell with SnS absorber by vapor transport deposition

    The SnS absorber layer in solar cell devices was produced by vapor transport deposition (VTD), which is a low-cost manufacturing method for solar modules. The performance of solar cells consisting of Si/Mo/SnS/ZnO/indium tin oxide (ITO) was limited by the SnS layer's surface texture and field-dependent carrier collection. For improved performance, a fluorine doped tin oxide (FTO) substrate was used in place of the Mo to smooth the topography of the VTD SnS and to make bifacial solar cells, which are potentially useful for multijunction applications. A bifacial SnS solar cell consisting of glass/FTO/SnS/CdS/ZnO/ITO demonstrated front- and back-side power conversion efficiencies of 1.2% and 0.2%, respectively.

  7. Bifacial solar cell with SnS absorber by vapor transport deposition

    Wangperawong, Artit [Stanford University, Stanford, California 94305 (United States); Department of Electrical Engineering, Faculty of Engineering, King Mongkut' s University of Technology Thonburi, Bangkok 10140 (Thailand); Hsu, Po-Chun; Yee, Yesheng; Herron, Steven M.; Clemens, Bruce M.; Cui, Yi; Bent, Stacey F., E-mail: sbent@stanford.edu [Stanford University, Stanford, California 94305 (United States)

    2014-10-27

    The SnS absorber layer in solar cell devices was produced by vapor transport deposition (VTD), which is a low-cost manufacturing method for solar modules. The performance of solar cells consisting of Si/Mo/SnS/ZnO/indium tin oxide (ITO) was limited by the SnS layer's surface texture and field-dependent carrier collection. For improved performance, a fluorine doped tin oxide (FTO) substrate was used in place of the Mo to smooth the topography of the VTD SnS and to make bifacial solar cells, which are potentially useful for multijunction applications. A bifacial SnS solar cell consisting of glass/FTO/SnS/CdS/ZnO/ITO demonstrated front- and back-side power conversion efficiencies of 1.2% and 0.2%, respectively.

  8. Bifacial solar cell with SnS absorber by vapor transport deposition

    Wangperawong, Artit; Hsu, Po-Chun; Yee, Yesheng; Herron, Steven M.; Clemens, Bruce M.; Cui, Yi; Bent, Stacey F.

    2014-10-01

    The SnS absorber layer in solar cell devices was produced by vapor transport deposition (VTD), which is a low-cost manufacturing method for solar modules. The performance of solar cells consisting of Si/Mo/SnS/ZnO/indium tin oxide (ITO) was limited by the SnS layer's surface texture and field-dependent carrier collection. For improved performance, a fluorine doped tin oxide (FTO) substrate was used in place of the Mo to smooth the topography of the VTD SnS and to make bifacial solar cells, which are potentially useful for multijunction applications. A bifacial SnS solar cell consisting of glass/FTO/SnS/CdS/ZnO/ITO demonstrated front- and back-side power conversion efficiencies of 1.2% and 0.2%, respectively.

  9. Effects of Absorber Emissivity on Thermal Performance of a Solar Cavity Receiver

    Jiabin Fang

    2014-01-01

    Full Text Available Solar cavity receiver is a key component to realize the light-heat conversion in tower-type solar power system. It usually has an aperture for concentrated sunlight coming in, and the heat loss is unavoidable because of this aperture. Generally, in order to improve the thermal efficiency, a layer of coating having high absorptivity for sunlight would be covered on the surface of the absorber tubes inside the cavity receiver. As a result, it is necessary to investigate the effects of the emissivity of absorber tubes on the thermal performance of the receiver. In the present work, the thermal performances of the receiver with different absorber emissivity were numerically simulated. The results showed that the thermal efficiency increases and the total heat loss decreases with increasing emissivity of absorber tubes. However, the thermal efficiency increases by only 1.6% when the emissivity of tubes varies from 0.2 to 0.8. Therefore, the change of absorber emissivity has slight effect on the thermal performance of the receiver. The reason for variation tendency of performance curves was also carefully analyzed. It was found that the temperature reduction of the cavity walls causes the decrease of the radiative heat loss and the convective heat loss.

  10. Heat loss study of trapezoidal cavity absorbers for linear solar concentrating collector

    There should be minimum heat loss from the absorber to achieve better efficiency of the solar collector. Overall heat loss coefficients of the trapezoidal cavity absorber with rectangular and round pipe were studied in the laboratory. Two identical rectangular pipe absorbers (section size: 100 x 23 mm, thickness: 2.5 mm and length 2170 mm) and two round pipe absorbers (a set of six mild steel round tubes of 16 mm diameter and 2.5 mm thickness brazed together in single layer making 100 mm width) were fabricated. A rectangular and a round pipe were painted with ordinary mat black paint (emissivity at 100 deg. C = 0.91) and one pipe of each type was coated with black nickel selective surface (emissivity at 100 deg. C = 0.17). Overall heat loss coefficient of the absorber was studied by circulating hot oil through it at different temperatures. The heat loss coefficient was increased with the absorber temperature. The heat loss coefficients for ordinary black coated and selective surface coated round pipe absorbers were varied from 3.5 to 7.5 W/m2/ deg. C and 2.7-5.8 W/m2/ deg. C respectively. The rectangular pipe section has marginally higher heat loss coefficients as compared to round pipe absorber. Selective surface coating on the absorbers reduced heat loss coefficient significantly by 20-30% as compared to ordinary black coating. The double glass cover also reduced heat loss coefficient by 10-15% as compared to single glass cover. The overall heat loss coefficients were also estimated analytically by parallel plate correlation and cavity correlations. The trend of variation of estimated heat loss coefficients by both methods was similar to experimental values. However, estimated values by cavity correlation were closure and uniformly distributed at all temperature range.

  11. CZTS solar cell device simulation with varying absorber thickness

    Frisk, Christopher; Ren, Yi; Li, Shu-Yi; Platzer-Björkman, Charlotte

    2015-01-01

    In this study the influence of absorber layer thickness on the trends of the four current-voltage (J-V) parameters for our CZTS solar cells is studied with simulations and compared with empirical data. In the case of dominating interface recombination we find that open-circuit voltage and fill-factor are largely unaffected of thickness variations 0.5 – 2.0 μm, whereas short-circuit current, and thereby efficiency, saturates (98 % of max) at >1.1 μm absorber thickness, in agreement with mea...

  12. Preparation and characterization of CuO nanostructures on copper substrate as selective solar absorbers

    Karthick Kumar, S. [Department of Natural Resources and Waste Recycling, School of Energy, Environment and Natural Resources, Madurai Kamaraj University, Madurai 625 021 (India); Murugesan, S., E-mail: smsan@mail.com [Department of Inorganic Chemistry, School of Chemistry, Madurai Kamaraj University, Madurai 625 021 (India); Suresh, S. [Department of Natural Resources and Waste Recycling, School of Energy, Environment and Natural Resources, Madurai Kamaraj University, Madurai 625 021 (India)

    2014-02-14

    Selective solar absorber coatings of copper oxide (CuO) on copper substrates are prepared by room temperature oxidation of copper at different alkaline conditions. The surface morphology and structural analyses of the CuO coatings are carried out by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and Raman spectroscopy techniques. XRD and Raman studies indicated the single phase nature and high crystallinity of the prepared CuO nanostructures. Different CuO nanostructures, viz., nanoneedles, nanofibers and nanoparticles are formed at different alkaline conditions. The influence of reaction time on morphology of the CuO nanostructures is also studied. The thermal emittance values of these nanostructured CuO samples are found to be in the range of 6–7% and their solar absorptances are ranged between 84 and 90%. The observed high solar selectivity values (>12.7) suggest that these coatings can be used as selective absorbers in solar thermal gadgets. - Highlights: • Nanostructured CuO thin films on Cu substrate have been prepared by a facile method. • Morphology of the CuO nanostructures varies with reaction pH. • The thin films show high absorptance in the visible region and low thermal emittance. • Multiple absorption in the porous structure leads to high solar absorptance. • Nanostructures posses solar selectivity values >12.

  13. Preparation and characterization of CuO nanostructures on copper substrate as selective solar absorbers

    Selective solar absorber coatings of copper oxide (CuO) on copper substrates are prepared by room temperature oxidation of copper at different alkaline conditions. The surface morphology and structural analyses of the CuO coatings are carried out by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and Raman spectroscopy techniques. XRD and Raman studies indicated the single phase nature and high crystallinity of the prepared CuO nanostructures. Different CuO nanostructures, viz., nanoneedles, nanofibers and nanoparticles are formed at different alkaline conditions. The influence of reaction time on morphology of the CuO nanostructures is also studied. The thermal emittance values of these nanostructured CuO samples are found to be in the range of 6–7% and their solar absorptances are ranged between 84 and 90%. The observed high solar selectivity values (>12.7) suggest that these coatings can be used as selective absorbers in solar thermal gadgets. - Highlights: • Nanostructured CuO thin films on Cu substrate have been prepared by a facile method. • Morphology of the CuO nanostructures varies with reaction pH. • The thin films show high absorptance in the visible region and low thermal emittance. • Multiple absorption in the porous structure leads to high solar absorptance. • Nanostructures posses solar selectivity values >12

  14. New Insight into the Angle Insensitivity of Ultrathin Planar Optical Absorbers for Broadband Solar Energy Harvesting.

    Liu, Dong; Yu, Haitong; Duan, Yuanyuan; Li, Qiang; Xuan, Yimin

    2016-01-01

    Two challenging problems still remain for optical absorbers consisting of an ultrathin planar semiconductor film on top of an opaque metallic substrate. One is the angle-insensitive mechanism and the other is the system design needed for broadband solar energy harvesting. Here, first we theoretically demonstrates that the high refractive index, instead of the ultrathin feature as reported in previous studies, is the physical origin of the angle insensitivity for ultrathin planar optical absorbers. They exhibit omnidirectional resonance for TE polarization due to the high complex refractive index difference between the semiconductor and the air, while for TM polarization the angle insensitivity persists up to an incident angle related to the semiconductor refractive index. These findings were validated by fabricating and characterizing an 18 nm Ge/Ag absorber sample (representative of small band gap semiconductors for photovoltaic applications) and a 22 nm hematite/Ag sample (representative of large band gap semiconductors for photoelectrochemical applications). Then, we took advantage of angle insensitivity and designed a spectrum splitting configuration for broadband solar energy harvesting. The cascaded solar cell and unassisted solar water splitting systems have photovoltaic and photoelectrochemical cells that are also spectrum splitters, so an external spectrum splitting element is not needed. PMID:27582317

  15. New Insight into the Angle Insensitivity of Ultrathin Planar Optical Absorbers for Broadband Solar Energy Harvesting

    Liu, Dong; Yu, Haitong; Duan, Yuanyuan; Li, Qiang; Xuan, Yimin

    2016-01-01

    Two challenging problems still remain for optical absorbers consisting of an ultrathin planar semiconductor film on top of an opaque metallic substrate. One is the angle-insensitive mechanism and the other is the system design needed for broadband solar energy harvesting. Here, first we theoretically demonstrates that the high refractive index, instead of the ultrathin feature as reported in previous studies, is the physical origin of the angle insensitivity for ultrathin planar optical absorbers. They exhibit omnidirectional resonance for TE polarization due to the high complex refractive index difference between the semiconductor and the air, while for TM polarization the angle insensitivity persists up to an incident angle related to the semiconductor refractive index. These findings were validated by fabricating and characterizing an 18 nm Ge/Ag absorber sample (representative of small band gap semiconductors for photovoltaic applications) and a 22 nm hematite/Ag sample (representative of large band gap semiconductors for photoelectrochemical applications). Then, we took advantage of angle insensitivity and designed a spectrum splitting configuration for broadband solar energy harvesting. The cascaded solar cell and unassisted solar water splitting systems have photovoltaic and photoelectrochemical cells that are also spectrum splitters, so an external spectrum splitting element is not needed. PMID:27582317

  16. Investigation of ZnO nanrod solar cells with layer-by-layer deposited CdTe quantum dot absorbers

    Briscoe, Joe

    2011-01-01

    Innovation in solar cell design is required to reduce cost and compete with traditional power generation. Current innovative solar technologies include nanostructured dye-sensitised solar cells and polymer solar cells, which both contain organic materials with limited lifetime. This project aims to combine the advantages of ZnO nanorods and quantum dot (QD) absorbers in an all-inorganic solar cell, using the layer-by-layer (LbL) process to increase light absorption in the cell....

  17. Analytical Study of the relationship Between an Absorber Cavity and Solar Fresnel Concentrator

    Pearson, J. Boise; Watson, Michael D.

    1998-01-01

    This paper presents an analytical study of the relationship between an engine absorber cavity and a solar concentrator in a solar thermal propulsion system. The engine is a thermal storage engine, and the concentrator consists of a primary thin-film fresnel concentrator and a secondary Compound Parabolic Concentrator. Two thermal models of the engine are developed, a blackbody cavity model and a 2D numerical model. Results of the two models are compared, with attention to the limitations of the blackbody model 'Me fresnel concentrator model is based on a Circle of Least Confusion approach. The results of the thermal and optical models are combined to create a combined model with absorber temperature predictions. This combined model approach is used to predict an optimum engine aperture size.

  18. Scanning tunneling spectroscopy on the chalcopyrite solar cell absorber material Cu(In,Ga)Se2

    Cu(In,Ga)Se2-based thin film solar cells have reached efficiencies close to 20%. Nevertheless, little is known about electronic transport and carrier recombination in this material on a microscopic scale. Especially grain boundaries in these polycrystalline materials are considered to play an important role in the performance of these solar cells. We applied scanning tunneling microscopy and spectroscopy to gain more insight in the electronic microstructure of the material. Our results point to lateral electronic inhomogeneities on the absorber surface and to an enhanced density of states at grain boundaries. The influence of charging effects is discussed

  19. Effects of Absorber Emissivity on Thermal Performance of a Solar Cavity Receiver

    Jiabin Fang; Nan Tu; Jinjia Wei

    2014-01-01

    Solar cavity receiver is a key component to realize the light-heat conversion in tower-type solar power system. It usually has an aperture for concentrated sunlight coming in, and the heat loss is unavoidable because of this aperture. Generally, in order to improve the thermal efficiency, a layer of coating having high absorptivity for sunlight would be covered on the surface of the absorber tubes inside the cavity receiver. As a result, it is necessary to investigate the effects of the emiss...

  20. Importance of Depletion Width on Charge Transport and Interfacial Recombination in Extremely Thin Absorber Solar Cells

    Edley, Michael; Jones, Treavor; Baxter, Jason

    The dynamics of charge carrier transport and recombination and their dependence on physical and electrochemical length scales in extremely thin absorber (ETA) solar cells is vital to cell design. We used J-V characterization, transient photocurrent / photovoltage, and electrochemical impedance spectroscopy to study electron transport and interfacial recombination in ETA cell. ETA cells were composed of ZnO nanowires coated with an ultrathin (5 nm) CdS buffer layer and CdSe absorbers with thicknesses of 10 - 40 nm, with polysulfide electrolyte. In thinner absorbers near short circuit, the depletion region can extend radially into the nanowire, inhibiting interfacial recombination rate. However, depleting the periphery of the nanowire reduces the cross sectional area for charge transport, resulting in longer characteristic collection times. Thicker absorbers suffered more significant bias-dependent collection, and we conclude that slight radial penetration of the depletion region into the nanowires enhances charge collection. This work highlights the importance of considering the impact of depletion width on charge transport and interfacial recombination in the design of liquid junction, semiconductor-sensitized solar cells.

  1. Effects of oxygen incorporation in solar cells with a-SiOx:H absorber layer

    Wang, Shuo; Smirnov, Vladimir; Chen, Tao; Holländer, Bernhard; Zhang, Xiaodan; Xiong, Shaozhen; Zhao, Ying; Finger, Friedhelm

    2015-01-01

    The effects of oxygen incorporation on layer properties and cell performance were investigated in thin film solar cells with a-SiOx:H absorber layers. Besides the widened optical band gap and increased defect densities, a doping effect is observed upon oxygen incorporation even for the layers with wide band gap. From comparison of solar cells illuminated from either p- or n-side, we conclude that overall hole carrier collection is strongly deteriorated by increasing the oxygen concentration. The donor-like states induced by oxygen reform the electric field in the absorber. The intensified electric field near the p/i interface improves the quantum efficiency (QE) around 400 nm, which is attributed to the better carrier collection in the p-layer. The maximum of QE shows a blue shift with both p- and n-side illumination. It is consistent with the enhanced optical band gap of the absorber layer and shows the potential of usage in multi-junction solar cells.

  2. PEDOT:PSS emitters on multicrystalline silicon thin-film absorbers for hybrid solar cells

    Junghanns, Marcus; Plentz, Jonathan; Andrä, Gudrun; Gawlik, Annett; Höger, Ingmar; Falk, Fritz

    2015-02-01

    We fabricated an efficient hybrid solar cell by spin coating poly(3,4-ethylene-dioxythiophene):polystyrenesulfonate (PEDOT:PSS) on planar multicrystalline Si (mc-Si) thin films. The only 5 μm thin Si absorber layers were prepared by diode laser crystallization of amorphous Si deposited by electron beam evaporation on glass. On these absorber layers, we studied the effect of SiOx and Al2O3 terminated Si surfaces. The short circuit density and power conversion efficiency (PCE) of the mc-Si/Al2O3/PEDOT:PSS solar cell increase from 20.6 to 25.4 mA/cm2 and from 7.3% to 10.3%, respectively, as compared to the mc-Si/SiOx/PEDOT:PSS cell. Al2O3 lowers the interface recombination and improves the adhesion of the polymer film on the hydrophobic mc-Si thin film. Open circuit voltages up to 604 mV were reached. This study demonstrates the highest PCE so far of a hybrid solar cell with a planar thin film Si absorber.

  3. Comparison of silicon oxide and silicon carbide absorber materials in silicon thin-film solar cells

    Walder Cordula

    2015-01-01

    Full Text Available Since solar energy conversion by photovoltaics is most efficient for photon energies at the bandgap of the absorbing material the idea of combining absorber layers with different bandgaps in a multijunction cell has become popular. In silicon thin-film photovoltaics a multijunction stack with more than two subcells requires a high bandgap amorphous silicon alloy top cell absorber to achieve an optimal bandgap combination. We address the question whether amorphous silicon carbide (a-SiC:H or amorphous silicon oxide (a-SiO:H is more suited for this type of top cell absorber. Our single cell results show a better performance of amorphous silicon carbide with respect to fill factor and especially open circuit voltage at equivalent Tauc bandgaps. The microstructure factor of single layers indicates less void structure in amorphous silicon carbide than in amorphous silicon oxide. Yet photoconductivity of silicon oxide films seems to be higher which could be explained by the material being not truly intrinsic. On the other hand better cell performance of amorphous silicon carbide absorber layers might be connected to better hole transport in the cell.

  4. Comparison of silicon oxide and silicon carbide absorber materials in silicon thin-film solar cells

    Walder, Cordula; Kellermann, Martin; Wendler, Elke; Rensberg, Jura; von Maydell, Karsten; Agert, Carsten

    2015-02-01

    Since solar energy conversion by photovoltaics is most efficient for photon energies at the bandgap of the absorbing material the idea of combining absorber layers with different bandgaps in a multijunction cell has become popular. In silicon thin-film photovoltaics a multijunction stack with more than two subcells requires a high bandgap amorphous silicon alloy top cell absorber to achieve an optimal bandgap combination. We address the question whether amorphous silicon carbide (a-SiC:H) or amorphous silicon oxide (a-SiO:H) is more suited for this type of top cell absorber. Our single cell results show a better performance of amorphous silicon carbide with respect to fill factor and especially open circuit voltage at equivalent Tauc bandgaps. The microstructure factor of single layers indicates less void structure in amorphous silicon carbide than in amorphous silicon oxide. Yet photoconductivity of silicon oxide films seems to be higher which could be explained by the material being not truly intrinsic. On the other hand better cell performance of amorphous silicon carbide absorber layers might be connected to better hole transport in the cell.

  5. CIGS absorber layer with double grading Ga profile for highly efficient solar cells

    Saadat, M.; Moradi, M.; Zahedifar, M.

    2016-04-01

    It is well-known that the band gap grading in CIGS solar cells is crucial for achieving highly efficient solar cells. We stimulate a CIGS solar cell and investigate the effects of the band gap grading on performance of the CIGS solar cell, where Ga/(Ga + In) ratio (GGI) at back (Cb) and front (Cf) of the absorber layer are considered constant. Our simulations show that by increasing the GGI at middle of CIGS absorber layer (Cm), the JSC decreases and VOC increases independent of the distance of the Cm from the back contact (Xm). For Cm lower than Cf, JSC increases and VOC decreases when the Xm shifts to the front of the CIGS layer. The behavior of JSC and VOC became reverse for the case of Cm greater than Cf. Almost in all of the structures, efficiency and FF have same behaviors. Our simulations show that the highest efficiency is obtained at Cm = 0.8 and Xm = 200 nm.

  6. BIONICOL. Development of a bionic solar collector with an aluminium roll-bond absorber; BIONICOL. Entwicklung eines bionischen Solarkollektors mit Aluminium-Rollbond-Absorber

    Hermann, Michael; Lunz, Karin [Fraunhofer-Institut fuer Solare Energiesysteme, Freiburg (Germany); Hillerns, Frank [TYFOROP Chemie GmbH, Hamburg (Germany)

    2010-07-01

    The authors of the contribution under consideration report on the development of a bionic solar collector with an aluminum roll-bond absorber. As part of the EU research project BIONICOL experiments and simulations are performed with respect to fluid mechanics, internal pressure stability and corrosion. First absorbers with a size of 1,060 mm x 1,820 mm are manufactured. The measured pressure loss is lower than the pressure loss of the hydraulically optimized volumetric absorber according to TREIKAUSKAS. Several studies suggest that adequate corrosion protection is achieved under conditions of stagnation, if TYFOCOR {sup registered} L in an aluminum roll bond-absorbers is used. Measurements at collectors (efficiency curve and stagnation behaviour) as well as the further development of the collector to prototypes for demonstration plants are planned as next steps.

  7. Unusual defect physics in CH3NH3PbI3 perovskite solar cell absorber

    Thin-film solar cells based on Methylammonium triiodideplumbate (CH3NH3PbI3) halide perovskites have recently shown remarkable performance. First-principle calculations show that CH3NH3PbI3 has unusual defect physics: (i) Different from common p-type thin-film solar cell absorbers, it exhibits flexible conductivity from good p-type, intrinsic to good n-type depending on the growth conditions; (ii) Dominant intrinsic defects create only shallow levels, which partially explain the long electron-hole diffusion length and high open-circuit voltage in solar cell. The unusual defect properties can be attributed to the strong Pb lone-pair s orbital and I p orbital antibonding coupling and the high ionicity of CH3NH3PbI3

  8. Comparing n- and p-type polycrystalline silicon absorbers in thin-film solar cells

    We have investigated fine grained polycrystalline silicon thin films grown by direct chemical vapor deposition on oxidized silicon substrates. More specifically, we analyze the influence of the doping type on the properties of this model polycrystalline silicon material. This includes an investigation of defect passivation and benchmarking of minority carrier properties. In our investigation, we use a variety of characterization techniques to probe the properties of the investigated polycrystalline silicon thin films, including Fourier Transform Photoelectron Spectroscopy, Electron Spin Resonance, Conductivity Activation, and Suns-Voc measurements. Amphoteric silicon dangling bond defects are identified as the most prominent defect type present in these layers. They are the primary recombination center in the relatively lowly doped polysilicon thin films at the heart of the current investigation. In contrast with the case of solar cells based on Czochralski silicon or multicrystalline silicon wafers, we conclude that no benefit is found to be associated with the use of n-type dopants over p-type dopants in the active absorber of the investigated polycrystalline silicon thin-film solar cells. - Highlights: • Comparison of n- and p-type absorbers for thin-film poly-Si solar cells • Extensive characterization of the investigated layers' characteristics • Literature review pertaining the use of n-type and p-type dopants in silicon

  9. Comparing n- and p-type polycrystalline silicon absorbers in thin-film solar cells

    Deckers, J. [imec, Kapeldreef 75, B-3001 Heverlee, Leuven (Belgium); ESAT, KU Leuven, Kardinaal Mercierlaan 94, B-3001 Heverlee, Leuven (Belgium); Bourgeois, E. [Institute for Materials Research (IMO), Hasselt University, Wetenschapspark 1, B-3590 Diepenbeek (Belgium); IMOMEC, IMEC vzw, Wetenschapspark 1, B-3590 Diepenbeek (Belgium); Jivanescu, M. [Department of Physics and Astronomy, University of Leuven, Celestijnenlaan 200D, B-3001 Heverlee, Leuven (Belgium); Abass, A. [Photonics Research Group (INTEC), Ghent University-imec, Sint-Pietersnieuwstraat 41, B-9000 Ghent (Belgium); Van Gestel, D.; Van Nieuwenhuysen, K.; Douhard, B. [imec, Kapeldreef 75, B-3001 Heverlee, Leuven (Belgium); D' Haen, J.; Nesladek, M.; Manca, J. [Institute for Materials Research (IMO), Hasselt University, Wetenschapspark 1, B-3590 Diepenbeek (Belgium); IMOMEC, IMEC vzw, Wetenschapspark 1, B-3590 Diepenbeek (Belgium); Gordon, I.; Bender, H. [imec, Kapeldreef 75, B-3001 Heverlee, Leuven (Belgium); Stesmans, A. [Department of Physics and Astronomy, University of Leuven, Celestijnenlaan 200D, B-3001 Heverlee, Leuven (Belgium); Mertens, R.; Poortmans, J. [imec, Kapeldreef 75, B-3001 Heverlee, Leuven (Belgium); ESAT, KU Leuven, Kardinaal Mercierlaan 94, B-3001 Heverlee, Leuven (Belgium)

    2015-03-31

    We have investigated fine grained polycrystalline silicon thin films grown by direct chemical vapor deposition on oxidized silicon substrates. More specifically, we analyze the influence of the doping type on the properties of this model polycrystalline silicon material. This includes an investigation of defect passivation and benchmarking of minority carrier properties. In our investigation, we use a variety of characterization techniques to probe the properties of the investigated polycrystalline silicon thin films, including Fourier Transform Photoelectron Spectroscopy, Electron Spin Resonance, Conductivity Activation, and Suns-Voc measurements. Amphoteric silicon dangling bond defects are identified as the most prominent defect type present in these layers. They are the primary recombination center in the relatively lowly doped polysilicon thin films at the heart of the current investigation. In contrast with the case of solar cells based on Czochralski silicon or multicrystalline silicon wafers, we conclude that no benefit is found to be associated with the use of n-type dopants over p-type dopants in the active absorber of the investigated polycrystalline silicon thin-film solar cells. - Highlights: • Comparison of n- and p-type absorbers for thin-film poly-Si solar cells • Extensive characterization of the investigated layers' characteristics • Literature review pertaining the use of n-type and p-type dopants in silicon.

  10. Black Cr/α-Cr2O3 nanoparticles based solar absorbers

    Monodisperse spherical core–shell particles of Cr/α-Cr2O3 with high adhesion were successfully coated on rough copper substrates by a simple self-assembly-like method for the use in solar thermal absorbers. The structure and morphology of the core-shell particles of Cr/α-Cr2O3 were effectively controlled by deposition temperature and the pH of the initial precursor solution. Their characterizations were carried out with X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry and attenuated total reflection, as well as UV–vis diffuse reflectance spectroscopy. The samples aged for more than 40 h at 75 °C exhibit the targeted high absorbing optical characteristic “Black chrome” while those aged for ≤40 h show a significant high UV–vis diffuse reflectance “green color”.

  11. Organic-inorganic hybrid perovskites as light absorbing/hole conducting material in solar cells

    Ghanavi, Saman

    2013-01-01

    Solar cells involving two different perovskites were manufactured and analyzed. The perovskites were (CH3NH3)PbI3 and (CH3NH3)SnI3. Both perovskites have a shared methyl ammonium group (MA) and are used as both light absorbing material and hole conducting material (HTM) in this project. The preparation procedures for the complete device were according to previous attempts to make stable organic-inorganic hybrid perovskites and involved different layers and procedures. Both perovskites were ma...

  12. Efficiency improvement in thin film solar cell devices with oxygen containing absorber layer.

    Emziane, M.; Durose, K; Halliday, D.P.; Bosio, N.; Romeo, N.

    2005-01-01

    The CdTe/CdS solar cell devices were grown using a dry process consisting of sputtering for the transparent conducting oxide and CdS window layers, and close-space sublimation for CdTe absorber layer. These devices were back contacted using Mo/Sb2Te3 sputtered layers following the CdCl2 activation process carried out in air. It was shown that when oxygen is intentionally introduced in the CdTe layer during its growth, this leads to a significant improvement in all the device parameters yieldi...

  13. Characteristics of exhaust air facades as solar absorbers for saving of heating energy

    Voncube, H. L.; Ludwig, E.

    1982-12-01

    The solar radiation exploited by solar exhaust air windows was measured at a building facing four main directions. The windows were not constructed as optimal radiation absorbers and the heat gain stood in a range of 3 to 10% of the heat consumption, depending on time of year. Optimal windows (chiefly clear glass with Venetian blinds) were found by a computer program simulating the process of radiation in an exhaust air-window and heat gains up to 50% can be obtained. Relation to air flow rate and others were found. The calculated results were proved by measurements. With a suitable heating systems in the building (heat transport form south side to north side, heat storage) up to 50% of the annual consumption can be saved.

  14. An Optical Characterization Technique for Parabolic Trough Solar Collectors Using Images of the Absorber Reflection

    Owkes, Jeanmarie Kathleen

    As the concentrating solar power industry competes to develop a less-expensive parabolic trough collector, assurance is needed that new parabolic trough collectors maintain accurate optical alignment. Previous optical characterization techniques are either too slow, ill-suited for field testing, or do not allow the collector to be tested in realistic orientations. The Observer method presented here enables the rapid optical characterization of parabolic trough collectors in any orientation in the field. The Observer method directly measures the combined optical angular errors in the reflector surface shape and the absorber position, which can be separated into its two components: reflector surface slope and absorber misalignment. The data acquisition requires the placement of photogrammetry targets on and around the collector. Multiple photographs of the absorber and its reflection are taken with a digital camera from different angles with respect to the collector. The images are processed to determine the camera location of each image using photogrammetry bundle analysis. The absorber and its reflection are found in the photographs using image-processing techniques. A Monte Carlo uncertainty model was developed to determine the uncertainty in the Observer measurements. The uncertainty was estimated for a wide array of measurement test scenarios to demonstrate the user's control over the measurement uncertainty. To validate the Observer method, the absorber alignment technique was compared to traditional photogrammetry; the absorber position measured with the two methods compared with a root-mean-square difference of 1.5 mm in the transverse direction and 0.86 mm along the optical axis. The reflector surface slope error measurement was compared to both VSHOT and SOFAST, two well-established optical characterization tools, by measuring a single reflector panel in the laboratory. The VSHOT and SOFAST measurements agreed with the Observer with a root

  15. Chemically vapor-deposited ZrB2 as a selective solar absorber

    Coatings of ZrB2 and TiB2 for photothermal solar absorber applications were prepared using chemical vapor deposition (CVD) techniques. Oxidation tests suggest a maximum temperature limit for air exposure of 600 K for TiB2 and 800 K for ZrB2. Both materials exhibit innate spectral selectivity with an emittance at 375 K ranging from 0.06 to 0.09, a solar absorptance for ZrB2 ranging from 0.67 to 0.77 and a solar absorptance for TiB2 ranging from 0.46 to 0.59. ZrB2 has better solar selectivity and more desirable oxidation behavior than TiB2. A 0.071 μm antireflection coating of Si3N4 deposited onto the ZrB2 coating leads to an increase in absorptance from 0.77 to 0.93, while the emittance remains unchanged. (Auth.)

  16. Non-tinted Transparent Luminescent Solar Concentrators Employing Both UV and NIR Selective Absorbers

    Zhao, Yimu; Lunt, Richard

    2014-03-01

    Luminescent solar concentrators are a potentially low-cost solar harvesting solution that additionally offer opportunities for integration around buildings and windows. However, the visible absorption and emission of previously demonstrated chromophores hamper their widespread applications including solar windows. Here, we demonstrate non-tinted transparent luminescent solar concentrators (TLSC) that employ both ultraviolet (UV) and near-infrared (NIR) selective absorbing luminophores that create an entirely new paradigm for power-producing transparent surfaces and enhances the potential over UV-only TLSCs. We have previously designed UV-harvesting systems composed of metal halide phosphorescent luminophore blends that enable absorption cutoff positioned at the edge of visible spectrum (430nm) and massive-downconverted emission in the near-infrared (800nm) with quantum yields for luminescence of 75%. Here, we have developed a complimentary TLSC employing fluorescent organic salts with both efficient NIR absorption and deeper NIR emission. We will discuss the photophysical properties of these luminophores, the impact of ligand-host control, and optimization of the TLSC architectures.

  17. A concentrated solar cavity absorber with direct heat transfer through recirculating metallic particles

    Sarker, M. R. I.; Saha, Manabendra; Beg, R. A.

    2016-07-01

    A recirculating flow solar particle cavity absorber (receiver) is modeled to investigate the flow behavior and heat transfer characteristics of a novel developing concept. It features a continuous recirculating flow of non-reacting metallic particles (black silicon carbide) with air which are used as a thermal enhancement medium. The aim of the present study is to numerically investigate the thermal behavior and flow characteristics of the proposed concept. The proposed solar particle receiver is modeled using two phase discrete particle model (DPM), RNG k-flow model and discrete ordinate (DO) radiation model. Numerical analysis is carried out considering a solar receiver with only air and the mixture of non-reacting particles and air as a heat transfer as well as heat carrying medium. The parametric investigation is conducted considering the incident solar flux on the receiver aperture and changing air flow rate and recirculation rate inside the receiver. A stand-alone feature of the recirculating flow solar particle receiver concept is that the particles are directly exposed to concentrated solar radiation monotonously through recirculating flow inside the receiver and results in efficient irradiation absorption and convective heat transfer to air that help to achieve high temperature air and consequently increase in thermal efficiency. This paper presents, results from the developed concept and highlights its flow behavior and potential to enhance the heat transfer from metallic particles to air by maximizing heat carrying capacity of the heat transfer medium. The imposed milestones for the present system will be helpful to understand the radiation absorption mechanism of the particles in a recirculating flow based receiver, the thermal transport between the particles, the air and the cavity, and the fluid dynamics of the air and particle in the cavity.

  18. Optimizing analysis of W-AlN cermet solar absorbing coatings

    The layer thickness and tungsten metal volume fraction of W-AlN cermet solar selective absorbing coatings on a W, Cu or Al infrared reflector with a surface aluminium oxynitride (AlON) or Al2O3 ceramic anti-reflector layer were optimized using physical modelling calculations. Due to limited published data for the refractive index of AlN, and likely oxygen contamination during reactive sputtering of AlN ceramic materials, AlON was used as the ceramic component and the published value of its refractive index was employed. The dielectric function and then the complex refractive index of W-AlON cermet materials were calculated using the Ping Sheng approximation. The downhill simplex method in multi-dimensions was used in the numerical calculation to achieve maximum photo-thermal conversion efficiency at 3500C under a concentration factor of 30 for a solar collector tube. Optimization calculation results show that the initial graded (ten-step layers) cermet films all converge to something close to a three-layer film structure, which consists of a low metal volume fraction cermet layer on a high metal volume fraction cermet layer on a metallic infrared reflector with a surface ceramic anti-reflection layer. The optimized three-layer solar coatings have a high solar absorptance of 0.95 for AlON and 0.96 for the Al2O3 anti-reflection layer, and a low hemispherical emittance of 0.073 at 350 deg. C. For the optimized three-layer films the solar radiation is efficiently absorbed internally and by phase interference. Thermal loss is very low for optimized three-layer films due to high reflectance values in the thermal infrared wavelength range and a very sharp edge between low solar reflectance and high thermal infrared reflectance. The high metal volume fraction cermet layer has a metal-like optical behaviour in the thermal infrared wavelength range and makes the largest contribution to the increase of emittance compared with that of the metal infrared reflector. (author)

  19. Experimental investigation on a semi-circular trough-absorber solar still with baffles for fresh water production

    Highlights: • Experiments are carried out to analyze the performance. • Baffles are placed in the absorber to increase the residence time of water with solar intensity. • Yield of fresh water from present solar still is 16.66% more than a conventional solar still. • Payback period of the present model is quicker. - Abstract: The main objective of this research is to increase the contact time of water in the basin to enhance yield of fresh water by using a semicircular absorber solar still with baffles. An experimental as well as theoretical investigation is carried out. The productivity and efficiency of present still are analyzed with the influence of the number baffles and the water flow rate. A good agreement between the experimental and theoretical results is observed. The results indicate that, the daily yield of present solar still is higher than that for conventional still approximately by 16.66%. The outlet water temperature present solar still is high subsequently, it can be coupled with multi-state of solar stills to increase productivity. Therefore, the present solar still can be sufficiently extended for other continuous solar desalination systems. Economic analysis concluded that, the payback period of the present model solar still is quicker while comparing it with other solar still

  20. Preparation and characterization of porous carbon–titania nanocomposite films as solar selective absorbers

    Highlights: • The nanocomposites porous C/TiO2 film were fabricated via PIPS method. • The HRTEM reveals the size of carbon nanoparticles is about 1.1 nm. • The PVP advantages residual carbon content but suppresses its crystallization. • The film exhibits high α (0.928–0.959) with low ε (0.074–0.105) for single layer. - Abstract: Newly proposed selective solar absorbers of porous carbon–titania nanocomposite films with a well-defined interconnected macropores structure were prepared via a polymer-assisted photopolymerization-induced phase-separation method. The microstructure and optical properties of as-deposited nanocomposite films were characterized and discussed in detail. The results show that non-ionic water-soluble polymer polyvinylpyrrolidone works as a sol modifier advantaging the mean size of the interconnected macropores, residual carbon content, and films thickness, but suppresses the order degree of the carbon remained in the films. The high-resolution transmission electron microscopy demonstrated that a small amount of graphite particles with size of around 1.1 nm embedded in the cavity of the porous while the wall of the porous consists of amorphous carbon and titania composites. The single layer of as-prepared porous C/TiO2 nanocomposite films exhibits high solar absorptance (α = 0.928–0.959) with low thermal emittance (ε = 0.074–0.105), yielding an optimized photothermal conversion efficiency η = α − ε of 0.864 corresponding to a film thickness of around 338 nm, indication of such film is fair enough to serve as an excellent solar absorber

  1. Preparation and characterization of porous carbon–titania nanocomposite films as solar selective absorbers

    Cheng, B.; Wang, K.K.; Wang, K.P.; Li, M.; Jiang, W.; Cong, B.J. [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Song, C.L. [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Key Laboratory of Advanced Materials and Applications for Batteries of Zhejiang Province (China); Jia, S.H. [Weihai Blue Star Glass Holding Co., Ltd., Weihai 264205 (China); Han, G.R. [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Key Laboratory of Advanced Materials and Applications for Batteries of Zhejiang Province (China); Liu, Y., E-mail: liuyong.mse@zju.edu.cn [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Key Laboratory of Advanced Materials and Applications for Batteries of Zhejiang Province (China)

    2015-06-25

    Highlights: • The nanocomposites porous C/TiO{sub 2} film were fabricated via PIPS method. • The HRTEM reveals the size of carbon nanoparticles is about 1.1 nm. • The PVP advantages residual carbon content but suppresses its crystallization. • The film exhibits high α (0.928–0.959) with low ε (0.074–0.105) for single layer. - Abstract: Newly proposed selective solar absorbers of porous carbon–titania nanocomposite films with a well-defined interconnected macropores structure were prepared via a polymer-assisted photopolymerization-induced phase-separation method. The microstructure and optical properties of as-deposited nanocomposite films were characterized and discussed in detail. The results show that non-ionic water-soluble polymer polyvinylpyrrolidone works as a sol modifier advantaging the mean size of the interconnected macropores, residual carbon content, and films thickness, but suppresses the order degree of the carbon remained in the films. The high-resolution transmission electron microscopy demonstrated that a small amount of graphite particles with size of around 1.1 nm embedded in the cavity of the porous while the wall of the porous consists of amorphous carbon and titania composites. The single layer of as-prepared porous C/TiO{sub 2} nanocomposite films exhibits high solar absorptance (α = 0.928–0.959) with low thermal emittance (ε = 0.074–0.105), yielding an optimized photothermal conversion efficiency η = α − ε of 0.864 corresponding to a film thickness of around 338 nm, indication of such film is fair enough to serve as an excellent solar absorber.

  2. Testing of a Receiver-Absorber-Converter (RAC) for the Integrated Solar Upper Stage (ISUS) program

    Westerman, Kurt O.; Miles, Barry J.

    1998-01-01

    The Integrated Solar Upper Stage (ISUS) is a solar bi-modal system based on a concept developed by Babcock & Wilcox in 1992. ISUS will provide advanced power and propulsion capabilities that will enable spacecraft designers to either increase the mass to orbit or decrease the cost to orbit for their satellites. In contrast to the current practice of using chemical propulsion for orbit transfer and photovoltaic conversion/battery storage for electrical power, ISUS uses a single collection, storage, and conversion system for both the power and propulsion functions. The ISUS system is currently being developed by the Air Force's Phillips Laboratory. The ISUS program consists of a systems analysis, design, and integration (SADI) effort, and three major sub-system development efforts: the Concentrator Array and Tracking (CATS) sub-system which tracks the sun and collects/focuses the energy; the Receiver-Absorber-Converter (RAC) sub-system which receives and stores the solar energy, transfers the stored energy to the propellant during propulsion operations, and converts the stored energy to electricity during power operations; and the Cryogenic Storage and Propellant Feed Sub-system (CSPFS) which stores the liquid hydrogen propellant and provides it to the RAC during propulsion operations. This paper discuses the evolution of the RAC sub-system as a result of the component level testing, and provides the initial results of systems level ground testing. A total of 5 RACs were manufactured as part of the Phillips Laboratory ISUS Technology Development program. The first series of component tests were carried out at the Solar Rocket Propulsion Laboratory at Edwards AFB, California. These tests provided key information on the propulsion mode of operations. The second series of RAC tests were performed at the Thermionic Evaluation Facility (TEF) in Albuquerque, New Mexico and provided information on the electrical performance of the RAC. The systems level testing was

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

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

    2015-12-14

    We report a novel promising quaternary sulfide (CuAgInS) to serve as a semiconductor sensitizer material in the photoelectrochemical field. In this study, CuAgInS (CAIS) sulfide sensitized ZnO nanorods were fabricated on ITO substrates through a facile and low-cost hydrothermal chemical method and applied on photoanodes for solar cells for the first time. The component and stoichiometry were key factors in determining the photoelectric performance of CAIS sulfide, which were controlled by modulating their reaction time. ZnO/Cu0.7Ag0.3InS2 nanoarrays exhibit an enhanced optical and photoelectric performance and the power conversion efficiency of ITO/ZnO/Cu0.7Ag0.3InS2/P3HT/Pt solid-state solar cell was up to 1.80%. The remarkable performance stems from improved electron transfer, a higher efficiency of light-harvesting and appropriate band gap alignment at the interface of the ZnO/Cu0.7Ag0.3InS2 NTs. The research indicates that CAIS as an absorbing material has enormous potential in solar cell systems. PMID:26553746

  4. Organic solar cells with graded absorber layers processed from nanoparticle dispersions

    Gärtner, Stefan; Reich, Stefan; Bruns, Michael; Czolk, Jens; Colsmann, Alexander

    2016-03-01

    The fabrication of organic solar cells with advanced multi-layer architectures from solution is often limited by the choice of solvents since most organic semiconductors dissolve in the same aromatic agents. In this work, we investigate multi-pass deposition of organic semiconductors from eco-friendly ethanol dispersion. Once applied, the nanoparticles are insoluble in the deposition agent, allowing for the application of further nanoparticulate layers and hence for building poly(3-hexylthiophene-2,5-diyl):indene-C60 bisadduct absorber layers with vertically graded polymer and conversely graded fullerene concentration. Upon thermal annealing, we observe some degrees of polymer/fullerene interdiffusion by means of X-ray photoelectron spectroscopy and Kelvin probe force microscopy. Replacing the common bulk-heterojunction by such a graded photo-active layer yields an enhanced fill factor of the solar cell due to an improved charge carrier extraction, and consequently an overall power conversion efficiency beyond 4%. Wet processing of such advanced device architectures paves the way for a versatile, eco-friendly and industrially feasible future fabrication of organic solar cells with advanced multi-layer architectures.

  5. Interfacial engineering of solution-processed Ni nanochain-SiOx (x solar selective absorbers

    Yu, Xiaobai; Wang, Xiaoxin; Zhang, Qinglin; Liu, Jifeng

    2016-04-01

    Cermet solar thermal selective absorber coatings are an important component of high-efficiency concentrated solar power (CSP) receivers. The oxidation of the metal nanoparticles in cermet solar absorbers is a great challenge for vacuum-free operation. Recently, we have demonstrated that oxidation is kinetically retarded in solution processed, high-optical-performance Ni nanochain-SiOx cermet system compared to conventional Ni-Al2O3 system when annealed in air at 450-600 °C for several hours. However, for long-term, high-temperature applications in CSP systems, thermodynamically stable antioxidation behavior is highly desirable, which requires new mechanisms beyond kinetically reducing the oxidation rate. Towards this goal, in this paper, we demonstrate that pre-operation annealing of Ni nanochain-SiOx cermets at 900 °C in N2 forms the thermodynamically stable orthorhombic phase of NiSi at the Ni/SiOx interfaces, leading to self-terminated oxidation at 550 °C in air due to this interfacial engineering. In contrast, pre-operation annealing at a lower temperature of 750 °C in N2 (as conducted in our previous work) cannot achieve interfacial NiSi formation directly, and further annealing in air at 450-600 °C for >4 h only leads to the formation of the less stable (metastable) hexagonal phase of NiSi. Therefore, the high-temperature pre-operation annealing is critical to form the desirable orthorhombic phase of NiSi at Ni/SiOx interfaces towards thermodynamically stable antioxidation behavior. Remarkably, with this improved interfacial engineering, the oxidation of 80-nm-diameter Ni nanochain-SiOx saturates after annealing at 550 °C in air for 12 h. Additional annealing at 550 °C in air for as long as 20 h (i.e., 32 h air annealing at >550 °C in total) has almost no further impact on the structural or optical properties of the coatings, the latter being very sensitive to any interfacial changes due to the localized surface plasmon resonances of the metal

  6. Growth and characterization of CdTe absorbers on GaAs by MBE for high concentration PV solar cells

    CdTe based II-VI absorbers are promising candidates for high concentration PV solar cells with an ideal band gap for AM1.5 solar radiation. In this study, we propose single crystal CdTe absorbers grown on GaAs substrates with a molecular beam epitaxy (MBE) which is a clean deposition technology. We show that high quality CdTe absorber layers can be grown with full width half maximum of X-ray diffraction rocking curves (XRD RC) as low as 227 arc-seconds with 0.5% thickness uniformity that a 2 μm layer is capable of absorbing 99% of AM1.5 solar radiation. Bandgap of the CdTe absorber is found as 1.483 eV from spetroscopic ellipsometry (SE) measurements. Also, high absorption coefficient is calculated from the results, which is ∝5 x 105cm-1 in solar radiation spectrum. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Growth and characterization of CdTe absorbers on GaAs by MBE for high concentration PV solar cells

    Ari, Ozan; Polat, Mustafa; Selamet, Yusuf [Department of Physics, Izmir Institute of Technology, Izmir 35430 (Turkey); Karakaya, Merve [Department of Material Science and Engineering, Izmir Institute of Technology, Izmir 35430 (Turkey)

    2015-11-15

    CdTe based II-VI absorbers are promising candidates for high concentration PV solar cells with an ideal band gap for AM1.5 solar radiation. In this study, we propose single crystal CdTe absorbers grown on GaAs substrates with a molecular beam epitaxy (MBE) which is a clean deposition technology. We show that high quality CdTe absorber layers can be grown with full width half maximum of X-ray diffraction rocking curves (XRD RC) as low as 227 arc-seconds with 0.5% thickness uniformity that a 2 μm layer is capable of absorbing 99% of AM1.5 solar radiation. Bandgap of the CdTe absorber is found as 1.483 eV from spetroscopic ellipsometry (SE) measurements. Also, high absorption coefficient is calculated from the results, which is ∝5 x 10{sup 5}cm{sup -1} in solar radiation spectrum. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Cubic TiO2 as a potential light absorber in solar-energy conversion

    Materials are currently sought for use in the photo-induced decomposition of water on crystalline electrodes. Titanium dioxide is valuable in this respect. The electronic structural properties of cubic TiO2 polymorphs were investigated by means of first-principles methods. We demonstrate that both fluorite- and pyrite-type TiO2 have important optical absorptive transitions in the region of the visible light. A cubic TiO2 phase that can efficiently absorb the sunlight would be an important candidate material for the development of the solar cells. Also, we present results on the Ti L edges for the two different titania forms. We predict that a qualitative spectroscopic discrimination of the cubic polymorphs can be achieved by following the Ti 2p→3d x-ray transitions

  9. Preparation of solar selective absorbing CuO coating for medium temperature application

    HUANG Qunwu; WANG Yiping; LI Jinhua

    2007-01-01

    A new method of preparing CuO solar selective absorbing coating for medium temperature is presented.After pretreatment,brass was overlaid with CuO by chemical plating.The effects of reactant concentration,reaction temperature and reaction time on the absorptivity of CuO coating were investigated.The optimized condition of preparing CuO coating was obtained.The CuO coating was analyzed with X-ray photoelectron spectroscopy(XPS) and scanning electron microscopy(SEM).In order to prolong the period of use,the CuO coating was protected by TiO2.The experiment shows that the TiO2/CuO coating is more heat-resistant,acid-resistant,and wear resistant than CuO coating,without Iosing absorptivity markedly.The TiO2 coating can reduce emissivity and protect the CuO coating.

  10. A Selective Metasurface Absorber with An Amorphous Carbon Interlayer for Solar Thermal Applications

    Wan, Chenglong; Nunez-Sanchez, S; Chen, Lifeng; Lopez-Garcia, M; Pugh, J; Zhu, Bofeng; Selvaraj, P; Mallick, T; Senthilarasu, S; Cryan, M J

    2016-01-01

    This paper presents fabrication, measurement and modelling results for a metal-dielectric-metal metasurface absorber for solar thermal applications. The structure uses amorphous carbon as an inter-layer between thin gold films with the upper film patterned with a 2D periodic array using focused ion beam etching. The patterned has been optimised to give high absorptance from 400-1200nm and low absorptance above this wavelength range to minimise thermal radiation and hence obtain higher temperature performance. Wide angle absorptance results are shown and detailed modelling of a realistic nanostructured upper layer results in excellent agreement between measured and modelled results. The use of gold in this paper is a first step towards a high temperature metasurface where gold can be replaced by other refractory metals such as tungsten or chrome.

  11. Indium doped zinc oxide nanowire thin films for antireflection and solar absorber coating applications

    Shaik, Ummar Pasha [ACRHEM, University of Hyderabad, Hyderabad-500046 (India); Krishna, M. Ghanashyam, E-mail: mgksp@uohyd.ac.in [ACRHEM and School of Physics, University of Hyderabad, Hyderabad-500046 (India)

    2014-04-24

    Indium doped ZnO nanowire thin films were prepared by thermal oxidation of Zn-In metal bilayer films at 500°C. The ZnO:In nanowires are 20-100 nm in diameter and several tens of microns long. X-ray diffraction patterns confirm the formation of oxide and indicate that the films are polycrystalline, both in the as deposited and annealed states. The transmission which is <2% for the as deposited Zn-In films increases to >90% for the ZnO:In nanowire films. Significantly, the reflectance for the as deposited films is < 10% in the region between 200 to 1500 nm and < 2% for the nanowire films. Thus, the as deposited films can be used solar absorber coatings while the nanowire films are useful for antireflection applications. The growth of nanowires by this technique is attractive since it does not involve very high temperatures and the use of catalysts.

  12. Use of nuclear techniques in the characterization of chrome black solar absorber surfaces

    A set of electrodeposited chrome black solar absorbers has been subjected to ion beam analysis in an attempt to determine the concentration depth profiles of the major elemental constituents. Chromium distributions were obtained using the 52Cr(p,γ)53Mn nuclear reaction, which is resonant at E = 1005.2 keV. The possibility was investigated of inferring oxygen distributions from the γ-ray lineshapes (measured with a Ge(Li) detector) of the direct capture reaction 16O(p,γ)17F. Concentration profiles were also obtained for fluorine and sodium contaminants in some chrome blacks. Complete experimental details are given of the various nuclear techniques used. The results of these measurements are discussed in terms of the microscopic physical features of the selective surfaces and are related to the known photothermal properties of the surfaces

  13. Global response to solar radiation absorbed by phytoplankton in a coupled climate model

    The global climate response to solar radiation absorbed by phytoplankton is investigated by performing multi-century simulations with a coupled ocean-atmosphere-biogeochemistry model. The absorption of solar radiation by phytoplankton increases radiative heating in the near-surface ocean and raises sea surface temperature (SST) by overall ∼0.5 C. The resulting increase in evaporation enhances specific atmospheric humidity by 2-5%, thereby increasing the Earth's greenhouse effect and the atmospheric temperatures. The Hadley Cell exhibits a weakening and poleward expansion, therefore reducing cloudiness at subtropical-middle latitudes and increasing it at tropical latitudes except near the Equator. Higher SST at polar latitudes reduces sea ice cover and albedo, thereby increasing the high-latitude ocean absorption of solar radiation. Changes in the atmospheric baroclinicity cause a poleward intensification of mid-latitude westerly winds in both hemispheres. As a result, the North Atlantic Ocean meridional overturning circulation extends more northward, and the equatorward Ekman transport is enhanced in the Southern Ocean. The combination of local and dynamical processes decreases upper-ocean heat content in the Tropics and in the subpolar Southern Ocean, and increases it at middle latitudes. This study highlights the relevance of coupled ocean-atmosphere processes in the global climate response to phytoplankton solar absorption. Given that simulated impacts of phytoplankton on physical climate are within the range of natural climate variability, this study suggests the importance of phytoplankton as an internal constituent of the Earth's climate and its potential role in participating in its long-term climate adjustments. (orig.)

  14. Structure, optical properties and thermal stability of Al2O3-WC nanocomposite ceramic spectrally selective solar absorbers

    Gao, Xiang-Hu; Wang, Cheng-Bing; Guo, Zhi-Ming; Geng, Qing-Fen; Theiss, Wolfgang; Liu, Gang

    2016-08-01

    Traditional metal-dielectric composite coating has found important application in spectrally selective solar absorbers. However, fine metal particles can easily diffuse, congregate, or be oxidized at high temperature, which causes deterioration in the optical properties. In this work, we report a new spectrally selective solar absorber coating, composed of low Al2O3 ceramic volume fraction (Al2O3(L)-WC) layer, high Al2O3 ceramic volume fraction (Al2O3(H)-WC layer) and Al2O3 antireflection layer. The features of our work are: 1) compared with the metal-dielectric composites concept, Al2O3-WC nanocomposite ceramic successfully achieves the all-ceramic concept, which exhibits a high solar absorptance of 0.94 and a low thermal emittance of 0.08, 2) Al2O3 and WC act as filler material and host material, respectively, which are different from traditional concept, 3) Al2O3-WC nanocomposite ceramic solar absorber coating exhibits good thermal stability at 600 °C. In addition, the solar absorber coating is successfully modelled by a commercial optical simulation programme, the result of which agrees with the experimental results.

  15. FracTherm - fractal hydraulic structures for energy efficient solar absorbers and other heat exchangers

    Hermann, M. [Fraunhofer Inst. for Solar Energy Systems, Freiburg (Germany)

    2004-07-01

    The energy efficiency of heat exchangers such as solar absorbers is determined both by their thermal efficiency - evaluated by the collector efficiency factor F' - and the primary energy which is needed to drive the pump transporting the fluid. The former is strongly influenced by the uniformity of the volume flow whereas the latter also depends on the pressure drop in the fluid channels. Thus, in order to obtain a high energy efficiency, it is necessary to ensure a uniform flow distribution with low pressure drop. However, conventional hydraulic structures often show a high pressure drop (serial flow) or a non-uniform flow distribution (parallel flow). In contrast to these channel designs, many natural structures are built of multiple branched channels (''fractals''). The aim of a current research work, which is funded by the German Federal Environmental Foundation (DBU), is to transfer those principles of fluid channel design to technical applications (bionic approach) and compare the structures with conventional ones. This paper describes how fractal hydraulic structures are generated and assessed using hydraulic and thermal simulations. Flow experiments as well as thermography with an absorber model are shown. Furthermore, investigations of flow phenomena using Computational Fluid Dynamics (CFD) are presented. (orig.)

  16. Efficiency improvement in thin-film solar cell devices with oxygen-containing absorber layer

    The CdTe/CdS solar cell devices were grown using a dry process consisting of sputtering for the transparent conducting oxide and CdS window layers, and close-space sublimation for CdTe absorber layer. These devices were back contacted using Mo/Sb2Te3 sputtered layers following the CdCl2 activation process carried out in air. It was shown that when oxygen is intentionally introduced in the CdTe layer during its growth, this leads to a significant improvement in all the device parameters yielding an efficiency of 14% compared to 11.5% for devices fabricated in the same conditions but without intentional oxygen incorporation in CdTe. The data obtained were not altered following a light soaking. The devices were investigated by quantitative secondary ion mass spectrometry, which allowed insight into the distribution and amount of oxygen and chlorine within the entire device structure. Both impurities showed an increased concentration throughout the CdTe absorber layer

  17. A facile process to prepare copper oxide thin films as solar selective absorbers

    Copper oxide thin films as solar selective absorbers were conveniently prepared by one-step chemical conversion method. X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis-NIR spectra and Fourier transform infrared (FTIR) spectra were employed to characterize the composition, structure and optical properties of thin films. The results indicated that the composition, structure and optical properties of thin films were greatly influenced by reaction temperature, time and concentration of NaOH. When reaction temperature was fixed at 40 deg. C, the as-prepared films consist of pure cubic Cu2O. The surface morphology of thin films was changed from square-like structure (reaction time ≤ 25 min) to porous belt-like structure (reaction time ≥ 30 min) with the elongation of reaction time. While for thin films prepared at 60 deg. C and 80 deg. C, single Cu2O was observed after 5 min reaction. When reaction time is longer than 5 min, CuO appears and the content of CuO is increasing with the elongation of reaction time. With the increase of reaction temperature, the belt-like structure was easily formed for 60 deg. C/10 min and 80 deg. C/5 min. Decreasing concentration of NaOH also could result in the formation of CuO and porous belt-like structure. Simultaneously, the film thickness is increasing with the increase of reaction time, temperature and concentration. Films containing CuO with belt-like structure exhibited high absorptance (>0.9), and the emissivity of films increased with elongation of reaction time. Combination of the composition, structure and optical properties, it can be deduced that the porous belt-like structure like as a light trap can greatly enhance absorbance (α), while the composition, thickness and roughness of thin films can greatly influence the emissivity (ε). The highest photo-thermal conversion efficiency was up to 0.86 (α/ε 0.94/0.08) for thin films prepared at 80 deg. C/5 min, which proved that the CuOx thin films can be

  18. A facile process to prepare copper oxide thin films as solar selective absorbers

    Xiao, Xiudi; Miao, Lei; Xu, Gang; Lu, Limei; Su, Zhanmin; Wang, Ning; Tanemura, Sakae

    2011-10-01

    Copper oxide thin films as solar selective absorbers were conveniently prepared by one-step chemical conversion method. X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis-NIR spectra and Fourier transform infrared (FTIR) spectra were employed to characterize the composition, structure and optical properties of thin films. The results indicated that the composition, structure and optical properties of thin films were greatly influenced by reaction temperature, time and concentration of NaOH. When reaction temperature was fixed at 40 °C, the as-prepared films consist of pure cubic Cu 2O. The surface morphology of thin films was changed from square-like structure (reaction time ≤ 25 min) to porous belt-like structure (reaction time ≥ 30 min) with the elongation of reaction time. While for thin films prepared at 60 °C and 80 °C, single Cu 2O was observed after 5 min reaction. When reaction time is longer than 5 min, CuO appears and the content of CuO is increasing with the elongation of reaction time. With the increase of reaction temperature, the belt-like structure was easily formed for 60 °C/10 min and 80 °C/5 min. Decreasing concentration of NaOH also could result in the formation of CuO and porous belt-like structure. Simultaneously, the film thickness is increasing with the increase of reaction time, temperature and concentration. Films containing CuO with belt-like structure exhibited high absorptance (>0.9), and the emissivity of films increased with elongation of reaction time. Combination of the composition, structure and optical properties, it can be deduced that the porous belt-like structure like as a light trap can greatly enhance absorbance ( α), while the composition, thickness and roughness of thin films can greatly influence the emissivity ( ɛ). The highest photo-thermal conversion efficiency was up to 0.86 ( α/ ɛ = 0.94/0.08) for thin films prepared at 80 °C/5 min, which proved that the CuO x thin films can be served as

  19. Characterization & Modification of Copper and Iron Oxide Nanoparticles for Application as Absorber Material in Silicon based Thin Film Solar Cells

    Nuys, Maurice

    2015-01-01

    The present thesis deals with the characterization and modification of semiconducting copper oxide (CuO, Cu2O) and iron oxide (gamma-Fe2O3, alpha-Fe2O3) nanoparticles, which provide a basis for an innovative solar cell concept involving nanoparticles composed of almost unlimitedly available elements as absorber material in thin film solar cells. This approach is promising to meet the requirements of increasing the production capacity and lowering the production costs if the nanoparticles exhi...

  20. Nanostructured CuO Thin Films Prepared through Sputtering for Solar Selective Absorbers

    Senthuran Karthick Kumar

    2013-01-01

    Full Text Available Nanostructured cupric oxide (CuO thin films have been deposited on copper (Cu substrates at different substrate temperatures and oxygen to argon gas ratios through direct current (DC reactive magnetron sputtering. The deposited CuO thin films are characterized by using X-ray diffraction (XRD, scanning electron microscopy (SEM, energy dispersive spectroscopy (EDS, profilometry, and spectrophotometry techniques. The crystalline phases, morphology, optical properties, and photothermal conversion efficiency of the CuO thin films are found to be significantly influenced by the change in substrate temperature and oxygen to argon gas ratio. The variations in the substrate temperature and oxygen to argon gas ratio have induced changes in Cu+ and Cu2+ concentrations of the CuO thin films that result in corresponding changes in their optical properties. The CuO thin film prepared at a substrate temperature of 30°C and O2 to Ar gas ratio of 1 : 1 has exhibited high absorptance and low emittance; thus, it could be used as a solar selective absorber in solar thermal gadgets.

  1. Investigation of Non-Vacuum Deposition Techniques in Fabrication of Chalcogenide-Based Solar Cell Absorbers

    Alsaggaf, Ahmed

    2015-07-01

    The environmental challenges are increasing, and so is the need for renewable energy. For photovoltaic applications, thin film Cu(In,Ga)(S,Se)2 (CIGS) and CuIn(S,Se)2 (CIS) solar cells are attractive with conversion efficiencies of more than 20%. However, the high-efficiency cells are fabricated using vacuum technologies such as sputtering or thermal co-evaporation, which are very costly and unfeasible at industrial level. The fabrication involves the uses of highly toxic gases such as H2Se, adding complexity to the fabrication process. The work described here focused on non-vacuum deposition methods such as printing. Special attention has been given to printing designed in a moving Roll-to-Roll (R2R) fashion. The results show potential of such technology to replace the vacuum processes. Conversion efficiencies for such non-vacuum deposition of Cu(In,Ga)(S,Se)2 solar cells have exceeded 15% using hazardous chemicals such as hydrazine, which is unsuitable for industrial scale up. In an effort to simplify the process, non-toxic suspensions of Cu(In,Ga)S2 molecular-based precursors achieved efficiencies of ~7-15%. Attempts to further simplify the selenization step, deposition of CuIn(S,Se)2 particulate solutions without the Ga doping and non-toxic suspensions of Cu(In,Ga)Se2 quaternary precursors achieved efficiencies (~1-8%). The contribution of this research was to provide a new method to monitor printed structures through spectral-domain optical coherence tomography SD-OCT in a moving fashion simulating R2R process design at speeds up to 1.05 m/min. The research clarified morphological and compositional impacts of Nd:YAG laser heat-treatment on Cu(In,Ga)Se2 absorber layer to simplify the annealing step in non-vacuum environment compatible to R2R. Finally, the research further simplified development methods for CIGS solar cells based on suspensions of quaternary Cu(In,Ga)Se2 precursors and ternary CuInS2 precursors. The methods consisted of post deposition reactive

  2. Oxidation-resistant, solution-processed plasmonic Ni nanochain-SiOx (x < 2) selective solar thermal absorbers

    Metal oxidation at high temperatures has long been a challenge in cermet solar thermal absorbers, which impedes the development of atmospherically stable, high-temperature, high-performance concentrated solar power (CSP) systems. In this work, we demonstrate solution-processed Ni nanochain-SiOx (x 2 selective solar thermal absorbers that exhibit a strong anti-oxidation behavior up to 600 °C in air. The thermal stability is far superior to previously reported Ni nanoparticle-Al2O3 selective solar thermal absorbers, which readily oxidize at 450 °C. The SiOx (x 2 matrices are derived from hydrogen silsesquioxane and tetraethyl orthosilicate precursors, respectively, which comprise Si-O cage-like structures and Si-O networks. Fourier transform infrared spectroscopy shows that the dissociation of Si-O cage-like structures and Si-O networks at high temperatures have enabled the formation of new bonds at the Ni/SiOx interface to passivate the surface of Ni nanoparticles and prevent oxidation. X-ray photoelectron spectroscopy and Raman spectroscopy demonstrate that the excess Si in the SiOx (x x (x 2 systems. This oxidation-resistant Ni nanochain-SiOx (x < 2) cermet coating also exhibits excellent high-temperature optical performance, with a high solar absorptance of ∼90% and a low emittance ∼18% measured at 300 °C. These results open the door towards atmospheric stable, high temperature, high-performance solar selective absorber coatings processed by low-cost solution-chemical methods for future generations of CSP systems

  3. XPS and SIMS characterisation of TiOxNy solar absorber films

    Full text: TiOxNy thin films have useful properties as selective solar absorbers when used in tandem with a collector substrate. Such films are transparent across a reasonable window of the solar spectrum, but have low thermal emissivity. They are however limited by their thermal stability under the typical operating conditions they experience. In this study, TiOxNy films have been deposited on Si and Cu substrates using ion beam assisted deposition. The films are amorphous and x and y were controlled by altering the O2/N2 ratio in the gas source. After annealing at temperatures of 200 - 400 deg C, films have been depth profiled using Secondary Ion Mass Spectrometry. Profiles reveal the degradation of the film by migration of the substrate atoms through the films, to the sample surface. In general, films with x1 show improved stability, ultimately at the expense of a reduced transmission window. Thermal stability is also improved by the use of diffusion barriers either at the substrate film interface or at the surface of the film. However contrary to previous suggestions, the degradation mechanism involves the formation not of an oxide at the film surface but a phase which is nitrogen rich. The nature of this phase, formed by diffusion of the substrate atoms, has been investigated by X-ray photoelectron spectroscopy (XPS). These investigations reveal very complex behaviour in the early stages of film failure, with an almost intact TiOxNy layer surviving, but being progressively buried by the growth of the reaction layer at the film surface. Copyright (1999) Australian X-ray Analytical Association Inc

  4. Synthesis and properties of polyamide-Ag2S composite based solar energy absorber surfaces

    Krylova, Valentina; Baltrusaitis, Jonas

    2013-10-01

    Silver sulfide (Ag2S), an efficient solar light absorber, was synthesized using a modified chemical bath deposition (CBD) method and polyamide 6 (PA) as a host material via solution phase reaction between AgNO3 and Na2S2O3. X-ray diffraction (XRD) data showed a single, α-Ag2S (acanthite), crystalline phase present while surface and bulk chemical analyses, performed using X-ray photoelectron (XPS) and energy dispersive (EDS) spectroscopies, showed 2:1 Ag:S ratio. Direct and indirect bandgaps obtained from Tauc plots were 1.3 and 2.3 eV, respectively. Detailed surface chemical analysis showed the presence of three distinct sulfur species with majority component due to the Ag2S chemical bonds and minority components due to two types of oxygen-sulfur bonds. Conductivity of the resulting composite material was shown to change with the reaction time thus enabling to obtain controlled conductivity composite material. The synthesis method presented is based on the low solubility of Ag2S and is potentially green, no by-product producing, as all Ag2S nucleated outside the host material can be recycled into the process via dissolving it in HNO3.

  5. Synthesis and properties of polyamide–Ag{sub 2}S composite based solar energy absorber surfaces

    Krylova, Valentina, E-mail: valentina.krylova@ktu.lt [Department of Inorganic Chemistry, Kaunas University of Technology, Radvilenu st. 19, LT-50254 Kaunas (Lithuania); Baltrusaitis, Jonas, E-mail: j.baltrusaitis@utwente.nl [PhotoCatalytic Synthesis Group, MESA Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, Meander 229, P.O. Box 217, 7500 AE Enschede (Netherlands)

    2013-10-01

    Silver sulfide (Ag{sub 2}S), an efficient solar light absorber, was synthesized using a modified chemical bath deposition (CBD) method and polyamide 6 (PA) as a host material via solution phase reaction between AgNO{sub 3} and Na{sub 2}S{sub 2}O{sub 3}. X-ray diffraction (XRD) data showed a single, α-Ag{sub 2}S (acanthite), crystalline phase present while surface and bulk chemical analyses, performed using X-ray photoelectron (XPS) and energy dispersive (EDS) spectroscopies, showed 2:1 Ag:S ratio. Direct and indirect bandgaps obtained from Tauc plots were 1.3 and 2.3 eV, respectively. Detailed surface chemical analysis showed the presence of three distinct sulfur species with majority component due to the Ag{sub 2}S chemical bonds and minority components due to two types of oxygen–sulfur bonds. Conductivity of the resulting composite material was shown to change with the reaction time thus enabling to obtain controlled conductivity composite material. The synthesis method presented is based on the low solubility of Ag{sub 2}S and is potentially green, no by-product producing, as all Ag{sub 2}S nucleated outside the host material can be recycled into the process via dissolving it in HNO{sub 3}.

  6. Design of a Transpired Air Heating Solar Collector with an Inverted Perforated Absorber and Asymmetric Compound Parabolic Concentrator.

    Shams, Nasif

    2013-01-01

    absorber and an asymmetric compound parabolic concentrator was applied to increase the intensity of solar radiation incident on the perforated absorber. A 2D ray tracing model quantified optical efficiency at different incident angles within 27o to 89o incident angles. The beam efficiency was found to vary between 72% and 79% and diffuse efficiency was found to vary between 48.2% and 65%. The average thermal efficiency was found to be approximately 55%-65% with average radiation above 400 W/m...

  7. Seasonal Evolution and Interannual Variability of the Local Solar Energy Absorbed by the Arctic Sea Ice-Ocean System

    Perovich, Donald K.; Nghiem, Son V.; Markus, Thorsten; Schwieger, Axel

    2007-01-01

    The melt season of the Arctic sea ice cover is greatly affected by the partitioning of the incident solar radiation between reflection to the atmosphere and absorption in the ice and ocean. This partitioning exhibits a strong seasonal cycle and significant interannual variability. Data in the period 1998, 2000-2004 were analyzed in this study. Observations made during the 1997-1998 SHEBA (Surface HEat Budget of the Arctic Ocean) field experiment showed a strong seasonal dependence of the partitioning, dominated by a five-phase albedo evolution. QuikSCAT scatterometer data from the SHEBA region in 1999-2004 were used to further investigate solar partitioning in summer. The time series of scatterometer data were used to determine the onset of melt and the beginning of freezeup. This information was combined with SSM/I-derived ice concentration, TOVS-based estimates of incident solar irradiance, and SHEBA results to estimate the amount of solar energy absorbed in the ice-ocean system for these years. The average total solar energy absorbed in the ice-ocean system from April through September was 900 MJ m(sup -2). There was considerable interannual variability, with a range of 826 to 1044 MJ m(sup -2). The total amount of solar energy absorbed by the ice and ocean was strongly related to the date of melt onset, but only weakly related to the total duration of the melt season or the onset of freezeup. The timing of melt onset is significant because the incident solar energy is large and a change at this time propagates through the entire melt season, affecting the albedo every day throughout melt and freezeup.

  8. Heavy ion elastic recoil detection analysis of AlxOy/Pt/AlxOy multilayer selective solar absorber

    Highlights: • AlxOy/Pt/AlxOy solar absorber was thermally stable in air up to 500 °C for 2 h. • AlxOy/Pt/AlxOy solar absorber was investigated using HI-ERDA. • The cause of degradation of the coatings above 500 °C was identified. • An outward diffusion of Cu substrate towards the coating was observed at 600 °C. • At 700 °C, formation of CuO and Cu2O phases were confirmed. - Abstract: An AlxOy/Pt/AlxOy multilayer solar absorber for use in solar-thermal applications has been deposited onto copper substrate by electron beam (e-beam) vacuum evaporation at room temperature. Different samples were annealed at different temperatures in air and characterized by spectrophotometry, emissometry, heavy ion elastic recoil detection analysis (HI-ERDA), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS). The AlxOy/Pt/AlxOy multilayer solar absorbers heated up to 500 °C were found to exhibit good spectral selectivity (α/ε) of 0.951/0.08. However, beyond 500 °C the spectral selectivity decreased to 0.846/0.11, possibly due to thermally activated atomic interdiffusion profiles. HI-ERDA has been used to study depth-dependent atomic concentration profiles. These measurements revealed outward diffusion of the copper substrate towards the surface and therefore, the decrease in the constituents of the coating. The decrease in the intensity of Pt grains and formation of CuO and Cu2O phases at 700 °C were confirmed by XRD and EDS

  9. Two new methods used to simulate the circumferential solar flux density concentrated on the absorber of a parabolic trough solar collector

    Guo, Minghuan; Wang, Zhifeng; Sun, Feihu

    2016-05-01

    The optical efficiencies of a solar trough concentrator are important to the whole thermal performance of the solar collector, and the outer surface of the tube absorber is a key interface of energy flux. So it is necessary to simulate and analyze the concentrated solar flux density distributions on the tube absorber of a parabolic trough solar collector for various sun beam incident angles, with main optical errors considered. Since the solar trough concentrators are linear focusing, it is much of interest to investigate the solar flux density distribution on the cross-section profile of the tube absorber, rather than the flux density distribution along the focal line direction. Although a few integral approaches based on the "solar cone" concept were developed to compute the concentrated flux density for some simple trough concentrator geometries, all those integral approaches needed special integration routines, meanwhile, the optical parameters and geometrical properties of collectors also couldn't be changed conveniently. Flexible Monte Carlo ray trace (MCRT) methods are widely used to simulate the more accurate concentrated flux density distribution for compound parabolic solar trough concentrators, while generally they are quite time consuming. In this paper, we first mainly introduce a new backward ray tracing (BRT) method combined with the lumped effective solar cone, to simulate the cross-section flux density on the region of interest of the tube absorber. For BRT, bundles of rays are launched at absorber-surface points of interest, directly go through the glass cover of the absorber, strike on the uniformly sampled mirror segment centers in the close-related surface region of the parabolic reflector, and then direct to the effective solar cone around the incident sun beam direction after the virtual backward reflection. All the optical errors are convoluted into the effective solar cone. The brightness distribution of the effective solar cone is supposed

  10. High-temperature stable absorber coatings for linear concentrating solar thermal power plants; Hochtemperaturstabile Absorberschichten fuer linear konzentrierende solarthermische Kraftwerke

    Hildebrandt, Christina

    2009-03-23

    This work describes the development of new absorber coatings for different applications - para-bolic trough and linear Fresnel collectors - and operating conditions - absorber in vacuum or in air. The demand for higher efficiencies of solar thermal power plants using parabolic trough technology results in higher temperatures in the collectors and on the absorber tubes. As heat losses increase strongly with increasing temperatures, the need for a lower emissivity of the absorber coating at constant absorptivity arises. The linear Fresnel application envisions ab-sorber tubes stable in air at high temperatures of about 450 C, which are to date commercially not available. This work comprises the theoretical background, the modeling and the fabrication of absorber tubes including the technology transfer to a production-size inline sputter coater. In annealing tests and accompanying optical measurements, degradation processes have been observed and specified more precisely by material characterization techniques. The simulations provided the capability of different materials used as potential IR-reflector. The highest selectivity can be achieved by applying silver which consequently has been chosen for the application in absorber coatings of the parabolic trough technology. Thin silver films how-ever need to be stabilized when used at high temperatures. Appropriate barrier layers as well as process and layer parameters were identified. A high selectivity was achieved and stability of the absorber coating for 1200 h at 500 C in vacuum has been demonstrated. For the application in air, silver was also analyzed as a potential IR-reflector. Even though the stability could be increased considerably, it nevertheless proved to be insufficient. The main factors influencing stability in a positive way are the use of higher quality polishing, additional barrier layers and adequate process parameters. This knowledge was applied for developing coatings which are stable in air at

  11. Scanning tunneling spectroscopy on the chalcopyrite solar cell absorber material Cu(In,Ga)Se{sub 2}

    Moenig, Harry; Saez-Araoz, Rodrigo; Lux-Steiner, Martha [Freie Universitaet Berlin (Germany); Sadewasser, Sascha; Ennaoui, Ahmed; Kaufmann, Christian; Kropp, Timo; Lauermann, Iver; Muenchenberg, Tim; Schock, Hans-Werner; Streicher, Ferdinand [Hahn- Meitner-Institut Berlin (Germany)

    2007-07-01

    Cu(In,Ga)Se{sub 2}-based thin film solar cells have reached efficiencies close to 20%. Nevertheless, little is known about electronic transport and carrier recombination in this material on a microscopic scale. Especially grain boundaries in these polycrystalline materials are considered to play an important role in the performance of these solar cells. We applied scanning tunneling microscopy and spectroscopy to gain more insight in the electronic microstructure of the material. Our results point to lateral electronic inhomogeneities on the absorber surface and to an enhanced density of states at grain boundaries. The influence of charging effects is discussed.

  12. Three-dimensional reciprocal space profile of an individual nanocrystallite inside a thin-film solar cell absorber layer

    The strain profile of an individual Cu(In,Ga)Se2 nanocrystallite in a solar cell absorber layer is accessed using synchrotron radiation. We find that the investigated crystallite is inhomogeneously strained. The strain is most likely produced by a combination of intergranular strain and composition variations in nanocrystals inside the polycrystalline semiconductor film and carries information about the intercrystalline interaction. The measurements are made nondestructively and without additional sample preparation or x-ray beam nanofocusing. This is the first step towards measurements of strain profiles of individual crystallites inside a working solar cell. (paper)

  13. Year-round performance of a modified single-basin solar still with mica plate as a suspended absorber

    El-Sebaii, A.A.; Aboul-Enein, S.; Ramadan, M.R.I.; El-Bialy, E. [Tanta University (Egypt). Faculty of Science

    2000-01-01

    In a previous study, a single-basin solar still with suspended absorber (SBSSBA) made from aluminium was constructed and investigated experimentally and theoretically. It was found that the daily productivity of the still was about 20% higher than that of the conventional single-basin solar still (SBSS). In this paper, the effect of thermal conductivity of the suspended absorber on the daily productivity of the still is investigated experimentally using aluminium, copper, stainless steel and mica plates as suspended absorbers. The results obtained are compared with those obtained for the SBSS tested under the same climatic conditions of Tanta (lat. 30{sup o} 47' N). The results indicate that it is advisable to use suspended plates made from insulating materials, such as mica, plastic, glass, etc. The daily productivity of the modified still with mica is found to be 42% higher than that of SBSS. Further, the effect of thickness of the suspended absorber on the productivity as well as the year-round performances of both SBSSBA and SBSS for the year 1996 are studied by computer simulation. There is good evidence that the productivity of SBSSBA is less dependent on the thickness of the suspended plate. The annual average productivities of the modified still with mica are found to be 23 and 15.8% higher than those of the conventional still when the basin water masses are 80 and 40 kg, respectively. This indicates that the suspended plate becomes more effective at higher masses of basin water. (author)

  14. Performance Study of Photovoltaic-Thermal (Pv/T) Solar Collector with ·-Grooved Absorber Plate

    A hybrid photovoltaic-thermal solar collector has been designed, built and its performance has been studied. The advantage of the collector is that it can generate electricity and heat simultaneously. Photovoltaic module SHARP NE-80E2EA with maximum output power of 80 W was used to generate electricity. The module also acts as heat absorber of the collector. Single pass ·-groove collector made of aluminium sheet with 0.7 mm thickness has been used to collect heat generated. Study was conducted under a designed halogen lamps solar simulator with intensities set at 386 ± 8 Wm-2 and 817 ± 8 Wm-2. The speed of air passing through the collector was set between (69.6 ± 2.2) x 10-4 kg/s to (695.8 ± 2.2) x 10-4 kg/s. The objective of the study is to compare the performance of PV/T collector with and without ·-groove absorber. The study found that the PV/T collector with ·-groove absorber plate has higher efficiency than the PV/T without ·-groove absorber. The electrical and thermal efficiencies are also increased when radiation intensity and speed of air increase. (author)

  15. SOLAR ABSORBING COOLING SYSTEMS BASED ON MULTISTAGE HEAT-MASS-TRANSFER DEVICES

    Doroshenko A.V.; Ludnitsky K.V.

    2014-01-01

    The article presents the worked out schematics for the alternative refrigeration systems and of air-conditioning systems, based on the use of absorbing cycle and of the sunny energy for the regeneration (renewals) of absorbent solution. We use here the cascade principle of construction of all heat-mass-transfer apparatus with variation of both the temperature level and the growth of absorbent concentration on the cascade stages. The heat-mass-transfer equipment as a part of the drying and coo...

  16. Preparation and characterization of CuInS2 absorber layers by sol-gel method for solar cell applications

    Amerioun, M. H.; Ghazi, M. E.; Izadifard, M.; Bahramian, B.

    2016-04-01

    CuInSe2 , CuInS2 ( CIS2 and CuInGaS2 alloys and their compounds with band gaps between 1.05 and 1.7eV are absorbance materials based on chalcopyrite, in which, because of their suitable direct band gap, high absorbance coefficient and short carrier diffusion are used as absorbance layers in solar cells. In this work, the effects of decrease in p H and thickness variation on characteristics of the CIS2 absorber layers, grown by spin coating on glass substrates, are investigated. Furthermore by using thiourea as a sulphur source in solvent, the sulfurization of layers was done easier than other sulfurization methods. Due to the difficulty in dissolving thiourea in the considered solvent that leads to a fast deposition during the dissolving process, precise conditions are employed in order to prepare the solution. In fact, this procedure can facilitate the sulfurization process of CuIn layers. The results obtained from this investigation indicate reductions in absorbance and band gap in the visible region of the spectrum as a result of decrease in p H. Finally, conductivity of layers is studied by the current vs. voltage curve that represents reduction of electrical resistance with decrease and increase in p H and thickness, respectively.

  17. Laser nanostructured Co nanocylinders-Al{sub 2}O{sub 3} cermets for enhanced & flexible solar selective absorbers applications

    Karoro, A., E-mail: angela@tlabs.ac.za [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure road, Somerset West 7129, PO Box 722, Western Cape (South Africa); Nuru, Z.Y.; Kotsedi, L.; Bouziane, Kh. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure road, Somerset West 7129, PO Box 722, Western Cape (South Africa); Mothudi, B.M. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Physics Dept., University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Maaza, M. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure road, Somerset West 7129, PO Box 722, Western Cape (South Africa)

    2015-08-30

    Highlights: • Co-Al{sub 2}O{sub 3} was synthesized by electrodeposition & femtosecond laser structuring. • The ultrafast laser structuring significantly increases the solar absorption. • Co-Al{sub 2}O{sub 3} exhibited 0.98 solar absorptance and 0.03 thermal emittance. - Abstract: We report on the structural and optical properties of laser surface structured Co nanocylinders-Al{sub 2}O{sub 3} cermets on flexible Aluminium substrate for enhanced solar selective absorbers applications. This new family of solar selective absorbers coating consisting of Co nanocylinders embedded into nanoporous alumina template which were produced by standard electrodeposition and thereafter submitted to femtosecond laser surface structuring. While their structural and chemical properties were investigated by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry and atomic force microscopy, their optical characteristics were investigated by specular & diffuse reflectance. The optimized samples exhibit an elevated optical absorptance α(λ) above 98% and an emittance ε(λ) ∼0.03 in the spectral range of 200–1100 nm. This set of values was suggested to be related to several surface and volume phenomena such as light trapping, plasmon surface effect as well as angular dependence of light reflection induced by the ultrafast laser multi-scale structuring.

  18. Laser nanostructured Co nanocylinders-Al2O3 cermets for enhanced & flexible solar selective absorbers applications

    Highlights: • Co-Al2O3 was synthesized by electrodeposition & femtosecond laser structuring. • The ultrafast laser structuring significantly increases the solar absorption. • Co-Al2O3 exhibited 0.98 solar absorptance and 0.03 thermal emittance. - Abstract: We report on the structural and optical properties of laser surface structured Co nanocylinders-Al2O3 cermets on flexible Aluminium substrate for enhanced solar selective absorbers applications. This new family of solar selective absorbers coating consisting of Co nanocylinders embedded into nanoporous alumina template which were produced by standard electrodeposition and thereafter submitted to femtosecond laser surface structuring. While their structural and chemical properties were investigated by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry and atomic force microscopy, their optical characteristics were investigated by specular & diffuse reflectance. The optimized samples exhibit an elevated optical absorptance α(λ) above 98% and an emittance ε(λ) ∼0.03 in the spectral range of 200–1100 nm. This set of values was suggested to be related to several surface and volume phenomena such as light trapping, plasmon surface effect as well as angular dependence of light reflection induced by the ultrafast laser multi-scale structuring

  19. METAL-POLYMER SOLAR COLLECTORS WITH MULTICHANNEL ABSORBER FOR MULTIFUNCTIONAL MULTIPURPOSE ENERGY SYSTEMS

    Doroshenko A.; Danko V.; Turbovets Y.

    2012-01-01

    New modification of liquid-metal-polymer solar collector for solar heating and for creation of multifunctional energy systems on its basis, particularly solar refrigeration systems was developed. A comparative study of several modifications of polymer collectors involving data of a set of foreign researchers was made and high efficiency of the new elaboration was proven.

  20. METAL-POLYMER SOLAR COLLECTORS WITH MULTICHANNEL ABSORBER FOR MULTIFUNCTIONAL MULTIPURPOSE ENERGY SYSTEMS

    Doroshenko A.

    2012-08-01

    Full Text Available New modification of liquid-metal-polymer solar collector for solar heating and for creation of multifunctional energy systems on its basis, particularly solar refrigeration systems was developed. A comparative study of several modifications of polymer collectors involving data of a set of foreign researchers was made and high efficiency of the new elaboration was proven.

  1. Ultrathin CIGS solar cells from controlled chemical etching of state of the art co-evaporated absorbers

    Full text : This presentation will present the influence of reducing the CIGSe absorber layer thickness by highly controlled bromine etching on the electrical and optical solar cell properties. When going from the standard 2.5 micron thickness to 500 nm films we observe a decrease in efficiency which is mainly caused by a reduced short circuit current. Even without deliberate light trapping or anti-reflection coating, an efficiency of 10.3% has been obtained for a 0.5 micron thick CIGSe absorber. A smoothing of the absorber surface was observed during the etching, its influence on the cell parameters will be discussed. Furthermore we monitored the increase of the surface band-gap, induced by the etching, which causes a slight increase of the open circuit voltage for thin absorber layers. Besides fundamental interest, ultrathin CIGS layers represents a key option to reduce the consumption of indium for large scale development. Acknowlegements : This study is carried out with the ULTRACIS project supported by the French National Research Agency

  2. Solar collector with an absorbent surface in the form of a venetian blind

    Kotowski, A.; Derczynski, M.; Machizaud, F.; Flechon, J.

    1984-11-01

    In order to increase the efficiency of flat plate air collectors, we propose the use of absorbing areas in the form of a venetian blind and composed of two planes of discontinuous and parallel lamellae. The theoretical analysis confirmed by the experimental results reveals that the energy parameters resulting from this structure are better than those obtained in the case of collectors using a single plane continuous absorbing surface.

  3. Investigation of blister formation in sputtered Cu2ZnSnS4 absorbers for thin film solar cells

    Blister formation in Cu2ZnSnS4 (CZTS) thin films sputtered from a quaternary compound target is investigated. While the thin film structure, composition, and substrate material are not correlated to the blister formation, a strong link between sputtering gas entrapment, in this case argon, and blistering effect is found. It is shown that argon is trapped in the film during sputtering and migrates to locally form blisters during the high temperature annealing. Blister formation in CZTS absorbers is detrimental for thin film solar cell fabrication causing partial peeling of the absorber layer and potential shunt paths in the complete device. Reduced sputtering gas entrapment, and blister formation, is seen for higher sputtering pressure, higher substrate temperature, and change of sputtering gas to larger atoms. This is all in accordance with previous publications on blister formation caused by sputtering gas entrapment in other materials

  4. Investigations into alterntive substrate, absorber, and buffer layer processing for Cu(In,Ga)Se{sub 2}-based solar cells

    Tuttle, J.R.; Berens, T.A.; Keane, J. [National Renewable Energy Lab., Golden, CO (United States)] [and others

    1996-05-01

    High-performance Cu(In,Ga)Se{sub 2}(CIGS)-based solar cells are presently fabricated within a narrow range of processing options. In this contribution, alternative substrate, absorber, and buffer layer processing is considered. Cell performance varies considerably when alternative substrates are employed. These variations are narrowed with the addition of Na via a Na{sub 2}S compound. Sputtered and electrodeposited CIGS precursors and completed absorbers show promise as alternatives to evaporation. A recrystallization process is required to improve their quality. (In,Ga){sub y}Se buffer layers contribute to cell performance above 10. Further improvements in these alternatives will lead to combined cell performance greater than 10% in the near term.

  5. Pinning down high-performance Cu-chalcogenides as thin-film solar cell absorbers: A successive screening approach.

    Zhang, Yubo; Wang, Youwei; Zhang, Jiawei; Xi, Lili; Zhang, Peihong; Zhang, Wenqing

    2016-05-21

    Photovoltaic performances of Cu-chalcogenides solar cells are strongly correlated with the absorber fundamental properties such as optimal bandgap, desired band alignment with window material, and high photon absorption ability. According to these criteria, we carry out a successive screening for 90 Cu-chalcogenides using efficient theoretical approaches. Besides the well-recognized CuInSe2 and Cu2ZnSnSe4 materials, several novel candidates are identified to have optimal bandgaps of around 1.0-1.5 eV, spike-like band alignments with CdS window layer, sharp photon absorption edges, and high absorption coefficients. These new systems have great potential to be superior absorbers for photovolatic applications if their carrrier transport and defect properties are properly optimized. PMID:27208964

  6. Pinning down high-performance Cu-chalcogenides as thin-film solar cell absorbers: A successive screening approach

    Zhang, Yubo; Wang, Youwei; Zhang, Jiawei; Xi, Lili; Zhang, Peihong; Zhang, Wenqing

    2016-05-01

    Photovoltaic performances of Cu-chalcogenides solar cells are strongly correlated with the absorber fundamental properties such as optimal bandgap, desired band alignment with window material, and high photon absorption ability. According to these criteria, we carry out a successive screening for 90 Cu-chalcogenides using efficient theoretical approaches. Besides the well-recognized CuInSe2 and Cu2ZnSnSe4 materials, several novel candidates are identified to have optimal bandgaps of around 1.0-1.5 eV, spike-like band alignments with CdS window layer, sharp photon absorption edges, and high absorption coefficients. These new systems have great potential to be superior absorbers for photovolatic applications if their carrrier transport and defect properties are properly optimized.

  7. Estimating Solar Irradiation Absorbed by Photovoltaic Panels with Low Concentration Located in Craiova, Romania

    Ionel L. Alboteanu; Cornelia A. Bulucea; Sonia Degeratu

    2015-01-01

    Solar irradiation is one of the important parameters that should be taken into consideration for the design and utilization of a photovoltaic system. Usually, the input parameters of a photovoltaic system are solar irradiation, the ambient environment temperature and the wind speed, and as a consequence most photovoltaic systems are equipped with sensors for measuring these parameters. This paper presents several mathematical models for solar irradiation assessment. The starting point is repr...

  8. Effect of Extended Extinction from Gold Nanopillar Arrays on the Absorbance Spectrum of a Bulk Heterojunction Organic Solar Cell

    Shu-Ju Tsai

    2015-02-01

    Full Text Available We report on the effects of enhanced absorption/scattering from arrays of Au nanopillars of varied size and spacing on the spectral response of a P3HT:PCBM bulk heterojunction solar cell. Nanopillar array-patterned devices do show increased optical extinction within a narrow range of wavelengths compared to control samples without such arrays. The measured external quantum efficiency and calculated absorbance, however, both show a decrease near the corresponding wavelengths. Numerical simulations indicate that for relatively narrow nanopillars, the increased optical extinction is dominated by absorption within the nanopillars, rather than scattering, and is likely dissipated by Joule heating.

  9. SOLAR ABSORBING COOLING SYSTEMS BASED ON MULTISTAGE HEAT-MASS-TRANSFER DEVICES

    Doroshenko A.V.

    2014-08-01

    Full Text Available The article presents the worked out schematics for the alternative refrigeration systems and of air-conditioning systems, based on the use of absorbing cycle and of the sunny energy for the regeneration (renewals of absorbent solution. We use here the cascade principle of construction of all heat-mass-transfer apparatus with variation of both the temperature level and the growth of absorbent concentration on the cascade stages. The heat-mass-transfer equipment as a part of the drying and cooling units is standardized and is executed by means of multistage monoblock compositions from poly-meric materials. The preliminary analysis of possibilities of the sunny systems in application to the tasks of cooling of environment and air-conditioning systems is carried out.

  10. Development of a new solid-state absorber material for dye-sensitized solar cell (DSSC)

    Swapna Lilly Cyriac; B Deepika; Bhaskaran Pillai; S V Nair; K R V Subramanian

    2014-05-01

    In contrast to the conventional DSSC systems, where the dye molecules are used as light harvesting material, here a solid-state absorber was used as a sensitizer in conjunction with the dye. The materials like ZnO and Al2O3 : C, which will show optically stimulated luminescence (OSL) upon irradiation were used as extremely thin absorber layers. This novel architecture allows broader spectral absorption, an increase in photocurrent, and hence, an improved efficiency because of the mobility of the trapped electrons in the absorber material after irradiation, to the TiO2 conduction band. Nanocrystalline mesoporous TiO2 photoanodes were fabricated using these solid-state absorber materials and after irradiation, a few number of samples were co-sensitized with N719 dye. On comparing both the dye loaded photoanodes (ZnO/TiO2 and Al2O3 : C/TiO2), it can be concluded from the present studies that, the Al2O3 : C is superior to ZnO under photon irradiation. Al2O3 : C is more sensitive to photon irradiation than ZnO and hence there can be more trap centres produced in Al2O3 : C.

  11. A facile fabrication of chemically converted graphene oxide thin films and their uses as absorber materials for solar cells

    Adelifard, Mehdi; Darudi, Hosein

    2016-07-01

    There is a great interest in the use of graphene sheets in thin film solar cells with low-cost and good-optoelectronic properties. Here, the production of absorbent conductive reduced graphene oxide (RGO) thin films was investigated. RGO thin films were prepared from spray-coated graphene oxide (GO) layers at various substrate temperature followed by a simple hydrazine-reducing method. The structural, morphological, optical, and electrical characterizations of graphene oxide (GO) and RGO thin films were investigated. X-ray diffraction analysis showed a phase shift from GO to RGO due to hydrazine treatment, in agreement with the FTIR spectra of the layers. FESEM images clearly exhibited continuous films resulting from the overlap of graphene nanosheets. The produced low-cost thin films had high absorption coefficient up to 1.0 × 105 cm-1, electrical resistance as low as 0.9 kΩ/sq, and effective optical band gap of about 1.50 eV, close to the optimum value for solar conversion. The conductive absorbent properties of the reduced graphene oxide thin films would be useful to develop photovoltaic cells.

  12. Electrodeposition of CdSe coatings on ZnO nanowire arrays for extremely thin absorber solar cells

    We report on electrodeposition of CdSe coatings onto ZnO nanowire arrays and determine the effect of processing conditions on material properties such as morphology and microstructure. CdSe-coated ZnO nanowire arrays have potential use in extremely thin absorber (ETA) solar cells, where CdSe absorbs visible light and injects photoexcited electrons into the ZnO nanowires. We show that room-temperature electrodeposition enables growth of CdSe coatings that are highly crystalline, uniform, and conformal with precise control over thickness and microstructure. X-ray diffraction and transmission electron microscopy show nanocrystalline CdSe in both hexagonal and cubic phases with grain size ∼5 nm. Coating morphology depends on electrodeposition current density. Uniform and conformal coatings were achieved using moderate current densities of ∼2 mA cm-2 for nanowires with roughness factor of ∼10, while lower current densities resulted in sparse nucleation and growth of larger, isolated islands. Electrodeposition charge density controls the thickness of the CdSe coating, which was exploited to investigate the evolution of the morphology at early stages of nucleation and growth. UV-vis transmission spectroscopy and photoelectrochemical solar cell measurements demonstrate that CdSe effectively sensitizes ZnO nanowires to visible light.

  13. Laser nanostructured Co nanocylinders-Al2O3 cermets for enhanced & flexible solar selective absorbers applications

    Karoro, A.; Nuru, Z. Y.; Kotsedi, L.; Bouziane, Kh.; Mothudi, B. M.; Maaza, M.

    2015-08-01

    We report on the structural and optical properties of laser surface structured Co nanocylinders-Al2O3 cermets on flexible Aluminium substrate for enhanced solar selective absorbers applications. This new family of solar selective absorbers coating consisting of Co nanocylinders embedded into nanoporous alumina template which were produced by standard electrodeposition and thereafter submitted to femtosecond laser surface structuring. While their structural and chemical properties were investigated by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry and atomic force microscopy, their optical characteristics were investigated by specular & diffuse reflectance. The optimized samples exhibit an elevated optical absorptance α(λ) above 98% and an emittance ɛ(λ) ∼0.03 in the spectral range of 200-1100 nm. This set of values was suggested to be related to several surface and volume phenomena such as light trapping, plasmon surface effect as well as angular dependence of light reflection induced by the ultrafast laser multi-scale structuring.

  14. Effect of thermal annealing in vacuum on the photovoltaic properties of electrodeposited Cu2O-absorber solar cell

    Dimopoulos T.

    2014-07-01

    Full Text Available Heterojunction solar cells were fabricated by electrochemical deposition of p-type, cuprous oxide (Cu2O absorber on sputtered, n-type ZnO layer. X-ray diffraction measurements revealed that the as-deposited absorber consists mainly of Cu2O, but appreciable amounts of metallic Cu and cupric oxide (CuO are also present. These undesired oxidation states are incorporated during the deposition process and have a detrimental effect on the photovoltaic properties of the cells. The open circuit voltage (VOC, short circuit current density (jSC, fill factor (FF and power conversion efficiency (η of the as-deposited cells are 0.37 V, 3.71 mA/cm2, 35.7% and 0.49%, respectively, under AM1.5G illumination. We show that by thermal annealing in vacuum, at temperatures up to 300 °C, compositional purity of the Cu2O absorber could be obtained. A general improvement of the heterojunction and bulk materials quality is observed, reflected upon the smallest influence of the shunt and series resistance on the transport properties of the cells in dark and under illumination. Independent of the annealing temperature, transport is dominated by the space-charge layer generation-recombination current. After annealing at 300 °C the solar cell parameters could be significantly improved to the values of: VOC = 0.505 V, jSC = 4.67 mA/cm2, FF = 47.1% and η = 1.12%.

  15. CuInGaAlSe2 Solar Absorbers On Flexible High-Temperature Substrates Project

    National Aeronautics and Space Administration — ITN Energy Systems (ITN) proposes to take the next step in spacecraft solar array development, building upon previous development and new findings to make the...

  16. Dependence of the efficiency of a CdS/CdTe solar cell on the absorbing layer's thickness

    On the basis of the continuity equation, the spatial distribution of photogenerated excess electrons in the neutral region of the CdTe layer in a CdS/CdTe heterostructure is analyzed taking into account recombination at the rear surface of the layer. It is demonstrated that, owing to diffusion, excess electrons penetrate deep into the CdTe layer at distances far exceeding the effective penetration length for solar radiation. Calculations of the short-circuit current indicate that, for electron lifetimes of 10-10-10-9 s, typical of thin-film CdS/CdTe solar cells, recombination losses are insignificant if the CdTe layer's thickness amounts to 3-4 μm but increase dramatically if the thickness is below 1-1.5 μm. In order to eliminate recombination losses in more efficient solar cells where the electron lifetime is ≥10-8 s the absorbing CdTe layer needs to be much thicker.

  17. Energy and exergy analysis of a new flat-plate solar air heater having different obstacles on absorber plates

    This study experimentally investigates performance analysis of a new flat-plate solar air heater (SAH) with several obstacles (Type I, Type II, Type III) and without obstacles (Type IV). Experiments were performed for two air mass flow rates of 0.0074 and 0.0052 kg/s. The first and second laws of efficiencies were determined for SAHs and comparisons were made among them. The values of first law efficiency varied between 20% and 82%. The values of second law efficiency changed from 8.32% to 44.00%. The highest efficiency were determined for the SAH with Type II absorbent plate in flow channel duct for all operating conditions, whereas the lowest values were obtained for the SAH without obstacles (Type IV). The results showed that the efficiency of the solar air collectors depends significantly on the solar radiation, surface geometry of the collectors and extension of the air flow line. The largest irreversibility was occurring at the SAH without obstacles (Type IV) collector in which collector efficiency is smallest. At the end of this study, the energy and exergy relationships are delivered for different SAHs.

  18. Experimental study of Nusselt number and Friction factor in solar air heater duct with Diamond shaped rib roughness on absorber plate

    S. S. Pawar

    2013-01-01

    Full Text Available - Solar air heater is used to heat air but it has low thermal efficiency because of low thermal conductivity between air and absorber plate. Thermal efficiency of solar air heater can be improved by creating artificial roughness on absorber plate which causes higher temperature to absorber plate and hence maximum thermal losses occurs to atmosphere. There are number of parameters which enhances the thermal conductivity such as relative roughness height (e/Dh, relative roughness pitch (P/e, Reynolds number (Re, and angle of attack (α.Experimental investigations were carried out to study heat transfer enhancement using diamond shape rib on absorber plate of solar air heater. Absorber plate is heated with the solar radiation in outdoor experiment whereas electric heater is used for indoor experiment. Setup is isolated from the three sides with Thermocol. The relative roughness pitch (p/e varies from 10 to 25 mm. The roughened wall has relative roughness height (e/Dh of 0.023mm and 0.028mm, angle of attack (α is 0° degree, rib height (e is 1 mm and 1.25 mm. Duct aspect ratio (W/H=8, rate of air flow corresponds to Reynolds no. (Re ranging from 3000-14000.Finally comparison of heat transfer and friction factor from both smooth and roughened plate under the similar condition of air flow is made.

  19. Solar Inactivation of Enterococci and Escherichia coli in Natural Waters: Effects of Water Absorbance and Depth.

    Maraccini, Peter A; Mattioli, Mia Catharine M; Sassoubre, Lauren M; Cao, Yiping; Griffith, John F; Ervin, Jared S; Van De Werfhorst, Laurie C; Boehm, Alexandria B

    2016-05-17

    The decay of sewage-sourced Escherichia coli and enterococci was measured at multiple depths in a freshwater marsh, a brackish water lagoon, and a marine site, all located in California. The marine site had very clear water, while the waters from the marsh and lagoon contained colored dissolved organic matter that not only blocked light but also produced reactive oxygen species. First order decay rate constants of both enterococci and E. coli were between 1 and 2 d(-1) under low light conditions and as high as 6 d(-1) under high light conditions. First order decay rate constants were well correlated to the daily average UVB light intensity corrected for light screening incorporating water absorbance and depth, suggesting endogenous photoinactivation is a major pathway for bacterial decay. Additional laboratory experiments demonstrated the presence of colored dissolved organic matter in marsh water enhanced photoinactivation of a laboratory strain of Enterococcus faecalis, but depressed photoinactivation of sewage-sourced enterococci and E. coli after correcting for UVB light screening, suggesting that although the exogenous indirect photoinactivation mechanism may be active against Ent. faecalis, it is not for the sewage-source organisms. A simple linear regression model based on UVB light intensity appears to be a useful tool for predicting inactivation rate constants in natural waters of any depth and absorbance. PMID:27119980

  20. Behavior of Electrochemically Prepared CuInSe2 as Photovoltaic Absorber in thin Film Solar Cells

    Two different objectives have been pursued in the present investigation: 1) optimization of the CuInSe, preparation parameters from electrodeposited precursors, and 2) evaluation of their photovoltaic behavior by preparing and enhancing Mo/CuInSe,/CdS/TCO devices. When Cu-In-Se precursors are directly electrodeposited, the applied potential fit is essential to improve the photovoltaic performance. Suitable absorbers have been also obtained by evaporating an In layer onto electrodeposited Cu-Se precursors. In this case, the substrate temperature during evaporation determines the CuInSe, quality. Similar results have been reached by substituting typical Mo-coated glass substrates by flexible Mo foils. Different TCO tested (ZnO and ITO) have been found equivalent as front electrical contact in the devices. Solar cell performance can be improved by annealing in air at 200 degree centigree. (Author) 46 refs

  1. Surface morphology and impurity distribution of electron beam recrystallized silicon films on low cost substrates for solar cell absorber

    FU Li; GROMBALL F; MüLLER J

    2006-01-01

    A line shaped electron beam recrystallised polycrystalline silicon film on the low cost substrate was investigated for the use of the solar cell absorber. The applied EB energy density strongly influences the surface morphology of the film system. Lower EB energy density results in droplet morphology and the rougher SiO2 capping layer due to the low fluidity. With the energy increasing, thecapping layer becomes smooth and continuous and less and small pinholes form in the silicon film. Tungstendisilicide (WSi2) is formed at the interface tungsten/silicon but also at the grain boundaries of the silicon. Because of the fast melting and cooling of the silicon film, the eutectic of silicon and tungstendisilicide mainly forms at the grain boundary of the primary silicon dendrites. The SEM-EDX analysis shows that there are no chlorine and hydrogen in the area surrounding a pinhole after recrystallization because of outgassing during the solidification.

  2. Spray pyrolytically grown NiAlOx cermets for solar thermal selective absorbers: spectral properties and thermal stability

    A Bagheri Khatibani; S M Rozati

    2016-02-01

    After deposition of NiAlOx thin films on stainless-steel substrates by the spray pyrolysis technique, various properties of the films were investigated using Fourier transform infrared spectroscopy, UV–visible reflectance spectrophotometry, energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Optical quantities were determined using reflectance spectra in the relevant spectrum region. At first the optimal substrate temperature was selected and then different nickel to aluminium ratios were examined to find the efficient solar absorber. The SEM revealed changes in morphology due to different molar ratios. The XRD of the selected sample showed a mixture of nickel and nickel oxide phases with the strong presence of substrate peaks and without the presence of alumina phase while in the EDX test the peaks corresponding to O, Al and Ni appeared. Long-term thermal stability study was performed by means of performance criterion concept.

  3. Thin-Film Solar Cells with InP Absorber Layers Directly Grown on Nonepitaxial Metal Substrates

    Zheng, Maxwell

    2015-08-25

    The design and performance of solar cells based on InP grown by the nonepitaxial thin-film vapor-liquid-solid (TF-VLS) growth technique is investigated. The cell structure consists of a Mo back contact, p-InP absorber layer, n-TiO2 electron selective contact, and indium tin oxide transparent top electrode. An ex situ p-doping process for TF-VLS grown InP is introduced. Properties of the cells such as optoelectronic uniformity and electrical behavior of grain boundaries are examined. The power conversion efficiency of first generation cells reaches 12.1% under simulated 1 sun illumination with open-circuit voltage (VOC) of 692 mV, short-circuit current (JSC) of 26.9 mA cm-2, and fill factor (FF) of 65%. The FF of the cell is limited by the series resistances in the device, including the top contact, which can be mitigated in the future through device optimization. The highest measured VOC under 1 sun is 692 mV, which approaches the optically implied VOC of ≈795 mV extracted from the luminescence yield of p-InP. The design and performance of solar cells based on indium phosphide (InP) grown by the nonepitaxial thin-film vapor-liquid-solid growth technique is investigated. The cell structure consists of a Mo back contact, p-InP absorber layer, n-TiO2 electron selective contact, and an indium tin oxide transparent top electrode. The highest measured open circuit voltage (VOC) under 1 sun is 692 mV, which approaches the optically implied VOC of ≈795 mV extracted from the luminescence yield of p-InP.

  4. Effect of atmospheric gases, surface albedo and cloud overlap on the absorbed solar radiation

    Ashok Sinha

    Full Text Available Recent studies have provided new evidence that models may systematically underestimate cloud solar absorption compared to observations. This study extends previous work on this "absorption anomaly'' by using observational data together with solar radiative transfer parameterisations to calculate fs (the ratio of surface and top of the atmosphere net cloud forcings and its latitudinal variation for a range of cloud types. Principally, it is found that (a the zonal mean behaviour of fs varies substantially with cloud type, with the highest values obtained for low clouds; (b gaseous absorption and scattering can radically alter the pattern of the variation of fs with latitude, but gaseous effects cannot in general raise fs to the level of around 1.5 as recently determined; (c the importance of the gaseous contribution to the atmospheric ASR is such that whilst fs rises with surface albedo, the net cloud contribution to the atmospheric ASR falls; (d the assumed form of the degree of cloud overlap in the model can substantially affect the cloud contribution to the atmospheric ASR whilst leaving the parameter fs largely unaffected; (e even large uncertainties in the observed optical depths alone cannot account for discrepancies apparent between modelled and newly observed cloud solar absorption. It is concluded that the main source of the anomaly may derive from the considerable uncertainties regarding impure droplet microphysics rather than, or together with, uncertainties in macroscopic quantities. Further, variable surface albedos and gaseous effects may limit the use of contemporaneous satellite and ground-based measurements to infer the cloud solar absorption from the parameter fs.

  5. Thermal stability of nitride solar selective absorbing coatings used in high temperature parabolic trough current

    2010-01-01

    This paper reports a new efficient solar selective surface in high temperature application.The influence of the monolayer’s microstructure and deposition rate was firstly discussed.Then the nitride nano-multilayer on the polished stainless steel (herein after referred as "SS") substrate was prepared with Ti and Al metal targets by DC.and R.F.magnetron co-sputtering.The samples were annealed in air at different temperatures ranging from 350 to 800°C for 2 h to evaluate their thermal stability.The samples’ surface and cross-section morphology,crystal structure,phase composition,optical properties were analyzed by scanning electron microscopy,X-ray diffraction,UV-VIS-NIR spectrophotometer and infrared emissivity tester.The results show that the coatings exhibit high solar selectivity (α/ε) of 0.943/0.08 even after heat-treatment up to 400°C for 2 h in air.After heat-treatment at 600°C in air,the solar selectivity decreases to 0.92/0.16.

  6. Low-Temperature Solution-Processed Kesterite Solar Cell Based on in Situ Deposition of Ultrathin Absorber Layer.

    Hou, Yi; Azimi, Hamed; Gasparini, Nicola; Salvador, Michael; Chen, Wei; Khanzada, Laraib S; Brandl, Marco; Hock, Rainer; Brabec, Christoph J

    2015-09-30

    The production of high-performance, solution-processed kesterite Cu2ZnSn(Sx,Se1-x)4 (CZTSSe) solar cells typically relies on high-temperature crystallization processes in chalcogen-containing atmosphere and often on the use of environmentally harmful solvents, which could hinder the widespread adoption of this technology. We report a method for processing selenium free Cu2ZnSnS4 (CZTS) solar cells based on a short annealing step at temperatures as low as 350 °C using a molecular based precursor, fully avoiding highly toxic solvents and high-temperature sulfurization. We show that a simple device structure consisting of ITO/CZTS/CdS/Al and comprising an extremely thin absorber layer (∼110 nm) achieves a current density of 8.6 mA/cm(2). Over the course of 400 days under ambient conditions encapsulated devices retain close to 100% of their original efficiency. Using impedance spectroscopy and photoinduced charge carrier extraction by linearly increasing voltage (photo-CELIV), we demonstrate that reduced charge carrier mobility is one limiting parameter of low-temperature CZTS photovoltaics. These results may inform less energy demanding strategies for the production of CZTS optoelectronic layers compatible with large-scale processing techniques. PMID:26353923

  7. Optimal thermo-hydraulic performance of solar air heater having chamfered rib-groove roughness on absorber plate

    Apurba Layek

    2010-07-01

    Full Text Available The use of an artificial roughness on a surface is an effective technique to enhance the rate of heat transfer to fluid flow in the duct of solar air heater. However, the increase in thermal energy gain is always accompanied by increase in pumping power. This paper is concerned with optimization of roughness parameters of solar air heater based on effective efficiency criterion. Effective efficiency of a solar air heater having repeated transverse chamfered rib–groove roughness on one broad wall has been computed using the correlations for heat transfer and friction factor developed within the investigated range of operating and system parameters. Roughness parameters viz. relative roughness pitch P/e, relative groove position g/P, chamfer angle , relative roughness height e/Dh and flow Reynolds number Re, have a combined effect on the heat transfer as well as fluid friction. The thermo-hydraulic performance of an air heater in terms of effective efficiency is determined on the basis of actual thermal energy gain subtracted by the primary energy required to generate power needed for pumping air through the roughened duct. Based on energy transfer mechanism to the absorber plate, a mathematical model is developed to compute effective efficiency. The selection of the optimal values of the roughness parameters involves the comparison of the enhancement of thermal performance and the increase of pumping losses as a result of using roughness in the collector system with that of the system without roughness. The effective efficiency criterion is maximized and reasonably optimized designs of roughness are found.

  8. Wavelength-dependent induction of UV absorbing mycosporine-like amino acids in the red alga Chondrus crispus under natural solar radiation

    Krabs, G; Bischof, K; Hanelt, D; Karsten, U; Wiencke, C

    2002-01-01

    Polychromatic response spectra for the induction of UV absorbing mycosporine-like amino acids (MAAs) were calculated after exposing small thalli of the red alga Chondrus crispus under various cut-off filters to natural solar radiation on the North Sea island Helgoland, Germany. The laboratory-grown

  9. Hydrocarbon pyrolysis reactor experimentation and modeling for the production of solar absorbing carbon nanoparticles

    Frederickson, Lee Thomas

    Much of combustion research focuses on reducing soot particulates in emissions. However, current research at San Diego State University (SDSU) Combustion and Solar Energy Laboratory (CSEL) is underway to develop a high temperature solar receiver which will utilize carbon nanoparticles as a solar absorption medium. To produce carbon nanoparticles for the small particle heat exchange receiver (SPHER), a lab-scale carbon particle generator (CPG) has been built and tested. The CPG is a heated ceramic tube reactor with a set point wall temperature of 1100-1300°C operating at 5-6 bar pressure. Natural gas and nitrogen are fed to the CPG where natural gas undergoes pyrolysis resulting in carbon particles. The gas-particle mixture is met downstream with dilution air and sent to the lab scale solar receiver. To predict soot yield and general trends in CPG performance, a model has been setup in Reaction Design CHEMKIN-PRO software. One of the primary goals of this research is to accurately measure particle properties. Mean particle diameter, size distribution, and index of refraction are calculated using Scanning Electron Microscopy (SEM) and a Diesel Particulate Scatterometer (DPS). Filter samples taken during experimentation are analyzed to obtain a particle size distribution with SEM images processed in ImageJ software. These results are compared with the DPS, which calculates the particle size distribution and the index of refraction from light scattering using Mie theory. For testing with the lab scale receiver, a particle diameter range of 200-500 nm is desired. Test conditions are varied to understand effects of operating parameters on particle size and the ability to obtain the size range. Analysis of particle loading is the other important metric for this research. Particle loading is measured downstream of the CPG outlet and dilution air mixing point. The air-particle mixture flows through an extinction tube where opacity of the mixture is measured with a 532 nm

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

    Atomic layer deposition (ALD) of TiS2 is investigated with titanium tetrachloride and hydrogen sulfide precursors. In-situ quartz crystal microbalance and ex-situ x-ray reflectivity measurements are carried out to study self-limiting deposition chemistry and material growth characteristics. The saturated growth rate is found to be ca. 0.5 Å/cycle within the ALD temperature window of 125–200 °C. As grown material is found poorly crystalline. ALD grown TiS2 is applied as a photon harvesting material for solid state sensitized solar cells with TiO2 as electron transport medium. Initial results with Spiro-OMeTAD as hole conducting layer show ca. 0.6% energy conversion efficiency under 1 sun illumination

  11. Hot carrier solar cell absorbers: investigation of carrier cooling properties of candidate materials

    Conibeer, G.; Shrestha, Santosh; Huang, Shujuan; Patterson, Robert; Xia, Hongze; Feng, Yu; Zhang, Pengfei; Gupta, Neeti; Smyth, Suntrana; Liao, Yuanxun; Lin, Shu; Wang, Pei; Dai, Xi; Chung, Simon; Yang, Jianfeng; Zhang, Yi

    2015-09-01

    The hot carrier cell aims to extract the electrical energy from photo-generated carriers before they thermalize to the band edges. Hence it can potentially achieve a high current and a high voltage and hence very high efficiencies up to 65% under 1 sun and 86% under maximum concentration. To slow the rate of carrier thermalisation is very challenging, but modification of the phonon energies and the use of nanostructures are both promising ways to achieve some of the required slowing of carrier cooling. A number of materials and structures are being investigated with these properties and test structures are being fabricated. Initial measurements indicate slowed carrier cooling in III-Vs with large phonon band gaps and in multiple quantum wells. It is expected that soon proof of concept of hot carrier devices will pave the way for their development to fully functioning high efficiency solar cells.

  12. Fabrication and characterization of a nanostructured TiO2/In2S3-Sb2S3/CuSCN extremely thin absorber (eta) solar cell

    Huerta-Flores, Alí M.; García-Gómez, Nora A.; de la Parra-Arciniega, Salomé M.; Sánchez, Eduardo M.

    2016-08-01

    In this work we report the successful assembly and characterization of a TiO2/In2S3-Sb2S3/CuSCN extremely thin absorber solar cell. Nanostructured TiO2 deposited by screen printing on an ITO substrate was used as an n-type electrode. An ∼80 nm extremely thin layer of the system In2S3-Sb2S3 deposited by successive ionic layer adsorption and a reaction (silar) method was used as an absorber. The voids were filled with p-type CuSCN and the entire assembly was completed with a gold contact. The solar cell fabricated with this heterostructure showed an energy conversion efficiency of 4.9%, which is a promising result in the development of low cost and simple fabrication of solar cells.

  13. Surfactant-free CZTS nanoparticles as building blocks for low-cost solar cell absorbers

    Zaberca, O.; Oftinger, F.; Chane-Ching, J. Y.; Datas, L.; Lafond, A.; Puech, P.; Balocchi, A.; Lagarde, D.; Marie, X.

    2012-05-01

    A process route for the fabrication of solvent-redispersible, surfactant-free Cu2ZnSnS4 (CZTS) nanoparticles has been designed with the objective to have the benefit of a simple sulfide source which advantageously acts as (i) a complexing agent inhibiting crystallite growth, (ii) a surface additive providing redispersion in low ionic strength polar solvents and (iii) a transient ligand easily replaced by an carbon-free surface additive. This multifunctional use of the sulfide source has been achieved through a fine tuning of ((Cu2+)a(Zn2+)b(Sn4+)c(Tu)d(OH-)e)t+, Tu = thiourea) oligomers, leading after temperature polycondensation and S2- exchange to highly concentrated (c > 100 g l-1), stable, ethanolic CZTS dispersions. The good electronic properties and low-defect concentration of the sintered, crack-free CZTSe films resulting from these building blocks was shown by photoluminescence investigation, making these building blocks interesting for low-cost, high-performance CZTSe solar cells.

  14. Surfactant-free CZTS nanoparticles as building blocks for low-cost solar cell absorbers.

    Zaberca, O; Oftinger, F; Chane-Ching, J Y; Datas, L; Lafond, A; Puech, P; Balocchi, A; Lagarde, D; Marie, X

    2012-05-11

    A process route for the fabrication of solvent-redispersible, surfactant-free Cu₂ZnSnS₄ (CZTS) nanoparticles has been designed with the objective to have the benefit of a simple sulfide source which advantageously acts as (i) a complexing agent inhibiting crystallite growth, (ii) a surface additive providing redispersion in low ionic strength polar solvents and (iii) a transient ligand easily replaced by an carbon-free surface additive. This multifunctional use of the sulfide source has been achieved through a fine tuning of ((Cu²⁺)(a)(Zn²⁺)(b)(Sn⁴⁺)(c)(Tu)(d)(OH⁻)(e))(t⁺), Tu = thiourea) oligomers, leading after temperature polycondensation and S²⁻ exchange to highly concentrated (c > 100 g l⁻¹), stable, ethanolic CZTS dispersions. The good electronic properties and low-defect concentration of the sintered, crack-free CZTSe films resulting from these building blocks was shown by photoluminescence investigation, making these building blocks interesting for low-cost, high-performance CZTSe solar cells. PMID:22513652

  15. Microstructure of absorber layers in CdTe/CdS solar cells

    Cousins, M A

    2001-01-01

    expected from extrapolating the linear trend in the bulk. These observations are explained in terms of the pinning of the CdTe grain size to the underlying CdS, and the small grain size this causes. A simple model was proposed for a link between the grain-growth to the efficiency improvement. The study also examines the behaviour of defects within grains upon CdCl sub 2 treatment provided the first direct evidence of recovery on CdCl sub 2 treatment in this system. Finally, a computer model is presented to describe the evolution of microstructure during growth. This is shown to be capable of reproducing the observed variation in grain size, but its strict physical accuracy is questioned. This work concerns the microstructure of CSS-grown CdTe layers used for CdTe/CdS solar cells. Particular attention is given to how the development of microstructure on annealing with CdCl sub 2 may correlate with increases in efficiency. By annealing pressed pellets of bulk CdTe powder, it is shown that microstructural change...

  16. Final Report: Tunable Narrow Band Gap Absorbers For Ultra High Efficiency Solar Cells

    Bedair, Salah M. [NCSU; Hauser, John R. [NCSU; Elmasry, Nadia [NCSU; Colter, Peter C. [NCSU; Bradshaw, G. [NCSU; Carlin, C. Z. [NCSU; Samberg, J. [NCSU; Edmonson, Kenneth [Spectrolab

    2012-07-31

    We report on a joint research program between NCSU and Spectrolab to develop an upright multijunction solar cell structure with a potential efficiency exceeding the current record of 41.6% reported by Spectrolab. The record efficiency Ge/GaAs/InGaP triple junction cell structure is handicapped by the fact that the current generated by the Ge cell is much higher than that of both the middle and top cells. We carried out a modification of the record cell structure that will keep the lattice matched condition and allow better matching of the current generated by each cell. We used the concept of strain balanced strained layer superlattices (SLS), inserted in the i-layer, to reduce the bandgap of the middle cell without violating the desirable lattice matched condition. For the middle GaAs cell, we have demonstrated an n-GaAs/i-(InGaAs/GaAsP)/p-GaAs structure, where the InxGa1-xAs/GaAs1-yPy SLS is grown lattice matched to GaAs and with reduced bandgap from 1.43 eV to 1.2 eV, depending upon the values of x and y.

  17. Proposal of a fluid flow layout to improve the heat transfer in the active absorber surface of solar central cavity receivers

    The main objective of concentrated solar power is to increase the thermal energy of a fluid, for the fluid to be used, for example, in a power cycle to generate electricity. Such applications present the requirement of appropriately designing the receiver active absorber surface, as the incident radiation flux can be very high. Besides that, the solar image in the receiver is not uniform, so conventional boilers designs are not well suited for these purposes. That point is particularly critical in solar central receivers systems (CRS), where concentrated solar flux is usually above 500 kW/m2, causing thermal and mechanical stress in the absorber panels. This paper analyzes a new thermofluidynamic design of a solar central receiver, which optimizes the heat transfer in the absorber surface. This conceptual receiver presents the following characteristics: the fluid flow pattern is designed according to the radiation flux map symmetry, so more uniform fluid temperatures at the receiver outlet are achieved; the heat transfer irreversibilities are reduced by circulating the fluid from the lower temperature region to the higher temperature region of the absorber surface; the width of each pass is adjusted to the solar flux gradient, to get lower temperature differences between the side tubes of the same pass; and the cooling requirement is ensured by means of adjusting the fluid flow velocity per tube, taking into account the pressure drop. This conceptual scheme has been applied to the particular case of a molten salt single cavity receiver, although the configuration proposed is suitable for other receiver designs and working fluids. - Highlights: ► The solar receiver design proposed optimizes heat transfer in the absorber surface. ► The fluid flow pattern is designed according to the solar flux map symmetry at noon. ► The fluid circulates from the lower to the higher temperature regions. ► The width of each pass is adjusted to the solar flux gradient. ► The

  18. Microstructure of absorber layers in CdTe/CdS solar cells

    Cousins, M.A

    2001-04-01

    This work concerns the microstructure of CSS-grown CdTe layers used for CdTe/CdS solar cells. Particular attention is given to how the development of microstructure on annealing with CdCl{sub 2} may correlate with increases in efficiency. By annealing pressed pellets of bulk CdTe powder, it is shown that microstructural change does occur on heating the material, enhanced by the inclusion of CdCl{sub 2} flux. However, the temperature required to cause significant effects is demonstrated to be higher than that at which heavy oxidation takes place. The dynamics of this oxidation are also examined. To investigate microstructural evolution in thin-films of CdTe, bi-layers of CdTe and CdS are examined by bevelling, thus revealing the microstructure to within {approx}1 {mu}m of the interface. This allows optical microscopy and subsequent image analysis of grain structure. The work shows that the grain-size, which is well described by the Rayleigh distribution, varies linearly throughout the layer, but is invariant under CdCl{sub 2} treatment. Electrical measurements on these bi-layers, however, showed increased efficiency, as is widely reported. This demonstrates that the efficiency of these devices is not dictated by the bulk microstructure. Further, the region within 1 {mu}m of the interface, of similar bi-layers to above, is examined by plan-view TEM. This reveals five-fold grain-growth on CdCl{sub 2} treatment. Moreover, these grains show a considerably smaller grain size than expected from extrapolating the linear trend in the bulk. These observations are explained in terms of the pinning of the CdTe grain size to the underlying CdS, and the small grain size this causes. A simple model was proposed for a link between the grain-growth to the efficiency improvement. The study also examines the behaviour of defects within grains upon CdCl{sub 2} treatment provided the first direct evidence of recovery on CdCl{sub 2} treatment in this system. Finally, a computer model is

  19. Microstructure of absorber layers in CdTe/CdS solar cells

    This work concerns the microstructure of CSS-grown CdTe layers used for CdTe/CdS solar cells. Particular attention is given to how the development of microstructure on annealing with CdCl2 may correlate with increases in efficiency. By annealing pressed pellets of bulk CdTe powder, it is shown that microstructural change does occur on heating the material, enhanced by the inclusion of CdCl2 flux. However, the temperature required to cause significant effects is demonstrated to be higher than that at which heavy oxidation takes place. The dynamics of this oxidation are also examined. To investigate microstructural evolution in thin-films of CdTe, bi-layers of CdTe and CdS are examined by bevelling, thus revealing the microstructure to within ∼1 μm of the interface. This allows optical microscopy and subsequent image analysis of grain structure. The work shows that the grain-size, which is well described by the Rayleigh distribution, varies linearly throughout the layer, but is invariant under CdCl2 treatment. Electrical measurements on these bi-layers, however, showed increased efficiency, as is widely reported. This demonstrates that the efficiency of these devices is not dictated by the bulk microstructure. Further, the region within 1 μm of the interface, of similar bi-layers to above, is examined by plan-view TEM. This reveals five-fold grain-growth on CdCl2 treatment. Moreover, these grains show a considerably smaller grain size than expected from extrapolating the linear trend in the bulk. These observations are explained in terms of the pinning of the CdTe grain size to the underlying CdS, and the small grain size this causes. A simple model was proposed for a link between the grain-growth to the efficiency improvement. The study also examines the behaviour of defects within grains upon CdCl2 treatment provided the first direct evidence of recovery on CdCl2 treatment in this system. Finally, a computer model is presented to describe the evolution of

  20. Effects of Thermochemical Treatment on CuSbS2 Photovoltaic Absorber Quality and Solar Cell Reproducibility

    de Souza Lucas, Francisco Willian; Welch, Adam W.; Baranowski, Lauryn L.; Dippo, Patricia C.; Hempel, Hannes; Unold, Thomas; Eichberger, Rainer; Blank, Beatrix; Rau, Uwe; Mascaro, Lucia H.; Zakutayev, Andriy

    2016-08-25

    CuSbS2 is a promising nontoxic and earth-abundant photovoltaic absorber that is chemically simpler than the widely studied Cu2ZnSnS4. However, CuSbS2 photovoltaic (PV) devices currently have relatively low efficiency and poor reproducibility, often due to suboptimal material quality and insufficient optoelectronic properties. To address these issues, here we develop a thermochemical treatment (TT) for CuSbS2 thin films, which consists of annealing in Sb2S3 vapor followed by a selective KOH surface chemical etch. The annealed CuSbS2 films show improved structural quality and optoelectronic properties, such as stronger band-edge photoluminescence and longer photoexcited carrier lifetime. These improvements also lead to more reproducible CuSbS2 PV devices, with performance currently limited by a large cliff-type interface band offset with CdS contact. Overall, these results point to the potential avenues to further increase the performance of CuSbS2 thin film solar cell, and the findings can be transferred to other thin film photovoltaic technologies.

  1. Performance Evaluation of a Solar Dryer with Finny, Perforated Absorber Plate Collector Equipped with an Air Temperature Control System for Dill Drying

    M Razmipour

    2016-04-01

    Full Text Available Dill is one of the most important plants in the world because of its medicinal properties and it is widely used as a vegetable in the most parts of Iran. In the present study a new solar dryer with finny, perforated absorber plate collector was utilized to dry fresh dill. The dryer was comprised of a solar collector, a product container, a fan and a drying air temperature controller. The temperature controller was used as a control system to regulate the drying air temperature. Thermal performance of the dryer with finny, perforated solar collector was compared with that of a simple flat plate solar collector at different airflow rates. The effect of drying air temperature at three levels (45, 55 and 65 °C, the product size at three lengths (3, 5 and 7 cm and two different modes of drying (mixed and indirect on the dryer performance was investigated. The results showed that the finny, perforated absorber plate solar collector could improve the thermal efficiency about 11% in comparison with the flat plate collector and the highest thermal efficiency was achieved at the maximum airflow rate. Meanwhile, increasing the air temperature and decreasing the product size caused a significant reduction in energy consumption. Solar fraction reduced by increasing the air temperature. Finally a maximum dryer efficiency of 70% was observed at air temperature of 65 oC, product size of 3 cm with mixed mode drying.

  2. Heavy ion elastic recoil detection analysis of Al{sub x}O{sub y}/Pt/Al{sub x}O{sub y} multilayer selective solar absorber

    Nuru, Z.Y., E-mail: zebibnate@yahoo.com [Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, Old Faure Road, 7129 Somerset West (South Africa); Dept. of Physics, University of Western Cape, Private Bag X 17, Bellville 7535 (South Africa); UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk ridge, PO Box 392, Pretoria South Africa (South Africa); Msimanga, M. [iThemba LABS Gauteng, Private Bag 11, WITS, 2050 Johannesburg (South Africa); Arendse, C.J. [Dept. of Physics, University of Western Cape, Private Bag X 17, Bellville 7535 (South Africa); Maaza, M. [Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, Old Faure Road, 7129 Somerset West (South Africa); Council for Scientific and Industrial Research, P O Box 395, Pretoria 0001 (South Africa); UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk ridge, PO Box 392, Pretoria South Africa (South Africa)

    2014-04-01

    Highlights: • Al{sub x}O{sub y}/Pt/Al{sub x}O{sub y} solar absorber was thermally stable in air up to 500 °C for 2 h. • Al{sub x}O{sub y}/Pt/Al{sub x}O{sub y} solar absorber was investigated using HI-ERDA. • The cause of degradation of the coatings above 500 °C was identified. • An outward diffusion of Cu substrate towards the coating was observed at 600 °C. • At 700 °C, formation of CuO and Cu{sub 2}O phases were confirmed. - Abstract: An Al{sub x}O{sub y}/Pt/Al{sub x}O{sub y} multilayer solar absorber for use in solar-thermal applications has been deposited onto copper substrate by electron beam (e-beam) vacuum evaporation at room temperature. Different samples were annealed at different temperatures in air and characterized by spectrophotometry, emissometry, heavy ion elastic recoil detection analysis (HI-ERDA), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS). The Al{sub x}O{sub y}/Pt/Al{sub x}O{sub y} multilayer solar absorbers heated up to 500 °C were found to exhibit good spectral selectivity (α/ε) of 0.951/0.08. However, beyond 500 °C the spectral selectivity decreased to 0.846/0.11, possibly due to thermally activated atomic interdiffusion profiles. HI-ERDA has been used to study depth-dependent atomic concentration profiles. These measurements revealed outward diffusion of the copper substrate towards the surface and therefore, the decrease in the constituents of the coating. The decrease in the intensity of Pt grains and formation of CuO and Cu{sub 2}O phases at 700 °C were confirmed by XRD and EDS.

  3. Atlas of albedo and absorbed solar radiation derived from Nimbus 7 earth radiation budget data set, November 1985 to October 1987

    Smith, G. Louis; Rutan, David; Bess, T. Dale

    1992-01-01

    An atlas of monthly mean global contour maps of albedo and absorbed solar radiation is presented for 21 months from Nov. 1985 to Oct. 1987. These data were retrieved from measurements made by the shortwave wide-field-of-view radiometer of the Earth Radiation Budget (ERB) instrument aboard the Nimbus 7 spacecraft. Profiles of zonal mean albedos and absorbed solar radiation were tabulated. These geographical distributions are provided as a resource for researchers studying the radiation budget of the Earth. The El Nino/Southern Oscillation event of 1986-1987 is included in this data set. This atlas of albedo and absorbed solar radiation extends to 12 years the period covered by two similar atlases: NASA RP-1230 (Jul. 1975 - Oct. 1978) and NASA RP-1231 (Nov. 1978 - Oct. 1985). These three compilations complement the atlases of outgoing longwave radiation by Bess and Smith in NASA RP-1185, RP-1186, and RP-1261, which were also based on the Nimbus 6 and 7 ERB data.

  4. Dependence of efficiency of thin-film CdS/CdTe solar cell on parameters of absorber layer and barrier structure

    Dependences of the open-circuit voltage, short-circuit current, fill factor, and efficiency of a CdS/CdTe solar cell on the resistivity and thickness of the p-CdTe absorber layer, the noncompensated acceptor concentration Na-Nd, and carrier lifetime τ in CdTe, are investigated, and optimization of these parameters in order to improve the solar cell efficiency is performed. It has been shown that the observed low efficiency of CdS/CdTe solar cells is caused by the too short electron lifetime in the range of 10-10-10-9 s and too thin (3-5 μm) CdTe layer currently used for fabrication of CdTe/CdS solar cells. To achieve an efficiency of 28-30%, the resistivity and thickness of the CdTe absorber layer, the noncompensated acceptor concentration, and carrier lifetime should be ∼ 0.1 Ω.cm, ≥ 20-30 μm, ≥ 1016 cm-3, and ≥ 10-6 s, respectively

  5. 太阳能甲烷重整反应中的催化活性吸收体%Catalytically Active Absorber in Solar Reforming of Methane

    桑丽霞; 孙彪; 李艳霞; 吴玉庭; 马重芳

    2011-01-01

    Solar reforming of methane has attracted a great attention because this reaction can realize energy storage of high-temperature heat from concentrated solar radiation and optimal utilization of resources of natural gas.Catalytically active absorber has a key role on absorption of solar energy and reforming of methane and becomes focus of solar reforming of methane research.The article introduces that the composition of catalytically active absorber and three types of catalytically active absorbers in terms of their matrix(porous alumina and SiC ceramics,metal foam,ceramic tubular array(nicknamed "porcupine")) combining the developments of reactor/receiver.Applied in directly irradiated solar reactor/receiver(volumetric reactor/receiver),the capability of catalytically active absorbers is mostly depended on the concentrated solar energy flux,matrix element,catalyst support(or washcoat) and active catalyst.According to the domestic and overseas researches,the future research directions and emphasis are analyzed and discussed.The future research should not only exploit the actual application system but also resolve the problem of uniform coating and combining between catalyst support and matrix for the high temperature reaction system.Photocatalytic enhancement of the reaction should also be taken into consideration,which will help to develop the cheap and efficient catalyst system.%太阳能甲烷重整反应可实现太阳能的高温蓄存和天然气资源的优化利用而备受关注,催化活性吸收体是进行太阳能吸收利用和甲烷催化重整的关键而成为太阳能甲烷重整反应研究的热点。本文在简述催化活性吸收体构成的基础上,结合重整反应器/接收器的发展,具体介绍了以多孔氧化铝和碳化硅陶瓷、泡沫金属及管状阵列陶瓷("porcupine")为基体的催化活性吸收体及其在太阳能甲烷重整反应中的应用,进而根据国内外的研究基础,分析

  6. Oxidation-resistant, solution-processed plasmonic Ni nanochain-SiO{sub x} (x < 2) selective solar thermal absorbers

    Yu, Xiaobai; Wang, Xiaoxin; Liu, Jifeng, E-mail: Jifeng.Liu@dartmouth.edu [Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, New Hampshire 03755 (United States); Zhang, Qinglin [Department of Chemical and Materials Engineering, University of Kentucky, 177 F. Paul Anderson Tower, Lexington, Kentucky 40506 (United States); Li, Juchuan [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2014-08-21

    Metal oxidation at high temperatures has long been a challenge in cermet solar thermal absorbers, which impedes the development of atmospherically stable, high-temperature, high-performance concentrated solar power (CSP) systems. In this work, we demonstrate solution-processed Ni nanochain-SiO{sub x} (x < 2) and Ni nanochain-SiO{sub 2} selective solar thermal absorbers that exhibit a strong anti-oxidation behavior up to 600 °C in air. The thermal stability is far superior to previously reported Ni nanoparticle-Al{sub 2}O{sub 3} selective solar thermal absorbers, which readily oxidize at 450 °C. The SiO{sub x} (x < 2) and SiO{sub 2} matrices are derived from hydrogen silsesquioxane and tetraethyl orthosilicate precursors, respectively, which comprise Si-O cage-like structures and Si-O networks. Fourier transform infrared spectroscopy shows that the dissociation of Si-O cage-like structures and Si-O networks at high temperatures have enabled the formation of new bonds at the Ni/SiO{sub x} interface to passivate the surface of Ni nanoparticles and prevent oxidation. X-ray photoelectron spectroscopy and Raman spectroscopy demonstrate that the excess Si in the SiO{sub x} (x < 2) matrices reacts with Ni nanostructures to form silicides at the interfaces, which further improves the anti-oxidation properties. As a result, Ni-SiO{sub x} (x < 2) systems demonstrate better anti-oxidation performance than Ni-SiO{sub 2} systems. This oxidation-resistant Ni nanochain-SiO{sub x} (x < 2) cermet coating also exhibits excellent high-temperature optical performance, with a high solar absorptance of ∼90% and a low emittance ∼18% measured at 300 °C. These results open the door towards atmospheric stable, high temperature, high-performance solar selective absorber coatings processed by low-cost solution-chemical methods for future generations of CSP systems.

  7. Unusual defect physics in CH{sub 3}NH{sub 3}PbI{sub 3} perovskite solar cell absorber

    Yin, Wan-Jian, E-mail: wanjian.yin@utoledo.edu; Shi, Tingting; Yan, Yanfa, E-mail: yanfa.yan@utoledo.edu [Department of Physics and Astronomy and Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, Ohio 43606 (United States)

    2014-02-10

    Thin-film solar cells based on Methylammonium triiodideplumbate (CH{sub 3}NH{sub 3}PbI{sub 3}) halide perovskites have recently shown remarkable performance. First-principle calculations show that CH{sub 3}NH{sub 3}PbI{sub 3} has unusual defect physics: (i) Different from common p-type thin-film solar cell absorbers, it exhibits flexible conductivity from good p-type, intrinsic to good n-type depending on the growth conditions; (ii) Dominant intrinsic defects create only shallow levels, which partially explain the long electron-hole diffusion length and high open-circuit voltage in solar cell. The unusual defect properties can be attributed to the strong Pb lone-pair s orbital and I p orbital antibonding coupling and the high ionicity of CH{sub 3}NH{sub 3}PbI{sub 3}.

  8. Experimental and numerical heat transfer analysis of a V-cavity absorber for linear parabolic trough solar collector

    Highlights: • A V-cavity absorber used in the linear parabolic trough collector was proposed. • The thermal performance was studied theoretically and experimentally. • Rectangular fins in the absorber enhanced the heat transfer. - Abstract: In the present study, a V-cavity absorber with rectangular fins that can be used in the linear parabolic trough collector (PTC) system was proposed and investigated both theoretically and experimentally. The optical performance of the absorber was studied by means of Monte-Carlo ray-tracing (MCRT) method. An energy balance model and a more detailed three-dimensional numerical model were developed to analyze the flow and heat transfer characteristics. Moreover, an experimental setup was built to validate the theoretical analysis. A reasonable agreement between the theoretical and experimental results was achieved, which proves the feasibility and reliability of the models. The results show that the sunlight could be reflected repeatedly by the triangle shape and nearly no sunlight escapes. The absorber with rectangular fins has a better heat transfer performance with higher outlet temperature of heat transfer fluid (HTF), lower temperature of heating surface and lower heat loss than those of absorber without fins. The effects of heat flux distribution, mass flow rate and direct normal irradiance on the heat transfer performance were further discussed. In addition, the variations of the heat transfer coefficient along z axial direction with different mass flow rates were also calculated based on the numerical results

  9. Improving Efficiency of Evaporated Cu2ZnSnS4 Thin Film Solar Cells by a Thin Ag Intermediate Layer between Absorber and Back Contact

    Hongtao Cui

    2015-01-01

    Full Text Available A 20 nm Ag coating on Mo back contact was adopted to improve the back contact of evaporated Cu2ZnSnS4 (CZTS solar cells. The Ag layer helped reduce the thickness of MoS2 which improves fill factor (FF significantly; additionally, it reduced secondary phases ZnS and SnS2−x, which may help carrier transport; it was also involved in the doping of the absorber layer, which compensated the intrinsic p-type doping and therefore drags down the doping level. The doping involvement may enlarge the depletion region and improve lifetime of the absorber, which led to enhancing open circuit voltage (VOC, short circuit current density (JSC, and efficiency significantly. However, it degrades the crystallinity of the material slightly.

  10. Investigation of blister formation in sputtered Cu{sub 2}ZnSnS{sub 4} absorbers for thin film solar cells

    Bras, Patrice, E-mail: patrice.bras@angstrom.uu.se [Midsummer AB, Elektronikhöjden 6, SE-17543 Järfälla, Sweden and Solid State Electronics, Angström Laboratory, Uppsala University, Box 534, SE-75121 Uppsala (Sweden); Sterner, Jan [Midsummer AB, Elektronikhöjden 6, SE-17543 Järfälla (Sweden); Platzer-Björkman, Charlotte [Solid State Electronics, Angström Laboratory, Uppsala University, Box 534, SE-75121 Uppsala (Sweden)

    2015-11-15

    Blister formation in Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films sputtered from a quaternary compound target is investigated. While the thin film structure, composition, and substrate material are not correlated to the blister formation, a strong link between sputtering gas entrapment, in this case argon, and blistering effect is found. It is shown that argon is trapped in the film during sputtering and migrates to locally form blisters during the high temperature annealing. Blister formation in CZTS absorbers is detrimental for thin film solar cell fabrication causing partial peeling of the absorber layer and potential shunt paths in the complete device. Reduced sputtering gas entrapment, and blister formation, is seen for higher sputtering pressure, higher substrate temperature, and change of sputtering gas to larger atoms. This is all in accordance with previous publications on blister formation caused by sputtering gas entrapment in other materials.

  11. FracTherm - fractal hydraulic structures for solar absorbers and other heat exchangers; FracTherm - Fraktale Hydraulikstrukturen fuer Solarabsorber und andere Waermetauscher

    Hermann, M. [Fraunhofer-Inst. fuer Solare Energiesysteme, Freiburg, Freiburg (Germany)

    2003-07-01

    Heat exchangers are important components of technical systems using conventional as well as renewable energy sources. Among these systems are solar collectors which absorb solar radiation and transfer it to a working fluid. The energy efficiency of such heat exchangers is determined both by thermal efficiency (heat transfer) and hydraulic energy (actually considered as primary energy) needed for pumping the fluid. Since raising thermal efficiency can lead to an increased demand for hydraulic power, this is a classical question of optimization. In conventional heat exchangers the fluid channels are usually arranged in series (e.g. serpentine absorber) or in parallel (e.g. parallel flow absorber). In contrast to these arrangements, natural constructions - such as blood vessels - show multiple branched structures which can mathematically be described as 'fractals'. The aim of the current research work, which is sponsored by the German Federal Environmental Foundation, is to transfer such structures to technical applications (bionic approach) and compare them with conventional constructions. At first, an algorithm which is capable of generating a multiple branched hydraulic network on a given area with fluid in- and outlet was developed. As a first step, this is just a pure geometric procedure. The appearance of the generated structures is strongly influenced by various geometric parameters. To evaluate thermal efficiency the heat exchanger surface is to be discretized by separating the structure into several absorber fins. The hydraulic power needed for pumping the fluid is considered as a second criterion to evaluate the structures. It is essential to determine the electrical energy demand of the pump in order to come to a total evaluation concerning primary energy. This is done with the simulation environment ColSim which can be used to calculate the pressure and volume flow distribution in hydraulic networks. Optimal geometric parameters can be found

  12. Energy-Efficient Sol-Gel Process for Production of Nanocomposite Absorber Coatings for Tubular Solar Thermal Collectors

    Scartezzini, Jean-Louis; Joly, Martin; Antonetti, Yann; Python, Martin; Gonzalez, Marina; Gascou, Thomas; Hessler, Aïcha; Schueler, Andreas

    2013-01-01

    The energy efficiency of production processes for components of solar energy systems is an important issue. Other factors which are important for the production of products such as black selective solar coatings include production speed, cycle time and homogeneity of the coating, as well as the minimization of the quantity of the needed chemical precursors. In this paper a new energy efficient production process is presented for production of optically selective coatings for solar thermal abs...

  13. Graphene and carbon black nano-composite polymer absorbers for a pyro-electric solar energy harvesting device based on LiNbO3 crystals

    Highlights: • A novel scheme for solar energy harvesting based on pyroelectric effect is proposed. • An optical system focusing solar radiation onto a LiNbO3 crystal is used. • Graphene and carbon black nano-composite polymer absorbers used as coating. • This configuration increases the amplitude of temperature variation experienced. • The whole solar spectrum is involved in the energy harvesting mechanism. - Abstract: A novel scheme for solar energy harvesting based on the pyro-electric effect has been demonstrated. The proposed harvester is based on an optical system focusing solar radiation onto a ferroelectric crystal (i.e. lithium niobate). The face exposed to the heating source is coated with a nanocomposite material (i.e. carbon black and graphene particles) that greatly improves the adsorption of solar radiation. The solar energy focused onto the crystal through a simple optical system allows one to induce a thermal gradient able to generate electric charges. Experiments have been carried out indoor as well as outdoor (in Pozzuoli, Naples, Italy, on December). Results show that two configurations appear to be preferable: (a) pyro-electric element with carbon black-based coating and a Fresnel lens (surface of about 100 cm2); (b) pyro-electric element with graphene-based coating and a Fresnel lens (surface of about 600 cm2). In both experimental arrangements the maximum temperature variation reached locally onto the lithium niobate substrate is relatively high with peaks greater than 250 °C. The maximum electrical power peak is of about 90 μW and about 50 μW for (a) and (b) respectively. The results of this first investigation are encouraging for further development of more efficient harvesting devices

  14. A Simple Aqueous Precursor Solution Processing of Earth-Abundant Cu2SnS3 Absorbers for Thin-Film Solar Cells.

    Suryawanshi, Mahesh P; Ghorpade, Uma V; Shin, Seung Wook; Pawar, Sachin A; Kim, In Young; Hong, Chang Woo; Wu, Minhao; Patil, Pramod S; Moholkar, Annasaheb V; Kim, Jin Hyeok

    2016-05-11

    A simple and eco-friendly method of solution processing of Cu2SnS3 (CTS) absorbers using an aqueous precursor solution is presented. The precursor solution was prepared by mixing metal salts into a mixture of water and ethanol (5:1) with monoethanolamine as an additive at room temperature. Nearly carbon-free CTS films were formed by multispin coating the precursor solution and heat treating in air followed by rapid thermal annealing in S vapor atmosphere at various temperatures. Exploring the role of the annealing temperature in the phase, composition, and morphological evolution is essential for obtaining highly efficient CTS-based thin film solar cells (TFSCs). Investigations of CTS absorber layers annealed at various temperatures revealed that the annealing temperature plays an important role in further improving device properties and efficiency. A substantial improvement in device efficiency occurred only at the critical annealing temperature, which produces a compact and void-free microstructure with large grains and high crystallinity as a pure-phase absorber layer. Finally, at an annealing temperature of 600 °C, the CTS thin film exhibited structural, compositional, and microstructural isotropy by yielding a reproducible power conversion efficiency of 1.80%. Interestingly, CTS TFSCs exhibited good stability when stored in an air atmosphere without encapsulation at room temperature for 3 months, whereas the performance degraded slightly when subjected to accelerated aging at 80 °C for 100 h under normal laboratory conditions. PMID:27105056

  15. Impact of environmental conditions on the chemical surface properties of Cu(In,Ga)(S,Se)2 thin-film solar cell absorbers

    Environmentally driven aging effects play a crucial role in thin-film solar cells based on Cu(In,Ga)(S,Se)2, both for long-term stability and short air exposure during production. For a better understanding of such effects, Cu(In,Ga)(S,Se)2 absorber surfaces were investigated by x-ray photoelectron and Auger electron spectroscopy after exposure to different environmental conditions. Identical absorbers were stored in a nitrogen atmosphere, in damp heat, and under ambient conditions for up to 14 days. We find varying degrees of diffusion of sulfur, copper, and sodium towards the surface, with potential impact on the electronic surface structure (band gap) and the properties of the interface to a buffer layer in a solar cell device. Furthermore, we observe an oxidation (in decreasing order) of indium, copper, and selenium (but no oxidation of sulfur). And finally, varying amounts of carbon- and oxygen-containing adsorbates are found. In particular, the findings suggest that, for ambient air exposure, sodium carbonate is formed at the surface

  16. Annealing effect on the structural and optical properties of Cr/α-Cr2O3 monodispersed particles based solar absorbers

    Graphical abstract: A cost-effective and environmentally friendly green chemical method, the so-called aqueous chemical growth (ACG) method, was used to deposit chromium/alpha-chromium(III) oxide, Cr/α-Cr2O3, monodispersed particles, for solar absorbers applications. Highlights: ► Cr/α-Cr2O3 have been deposited by the aqueous chemical growth (ACG) method. ► High temperature annealing affects the optical selectivity of the deposited particles. ► Oxygen diffusion to the interface at high temperature results in the oxidization of the substrate. - Abstract: A cost-effective and environmentally friendly green chemical method, the so-called aqueous chemical growth (ACG) method, was used to deposit chromium/alpha-chromium(III) oxide, Cr/α-Cr2O3, monodispersed particles, for solar absorbers applications. The deposited particles were annealed at various temperatures in a hydrogen atmosphere for 2 h to study the annealing temperature dependence of the structural, chemical and optical properties of the particles grown on tantalum substrates. The deposited Cr/α-Cr2O3 was characterized by X-ray diffraction (XRD), attenuated total reflection (ATR), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and diffuse reflectance UV–vis–NIR spectroscopy. The XRD and ATR analysis indicated that by increasing annealing temperature, the particles crystallinity was improved and Ta2O5 was formed around 600 °C, due to the fast oxygen diffusion from the deposited α-Cr2O3 toward the tantalum substrate. The optical measurements show that samples annealed at 400 and 500 °C exhibit the targeted high absorbing optical characteristics of “Black chrome”, while those annealed below 400 °C and above 500 °C show a significant low absorptivity and high emissivity.

  17. The use of solar cells for continuous recording of absorbed dose in the product during radiation sterilization

    As a result of the rapidly developing space programme, reliable solar panels were needed as an energy source for space capsules. It was found that when a space capsule passed through the Van Allen Belt, the solar panels aged owing to the radiation, and the energy output declined. The United States National Aeronautics and Space Administration investigated the pre-irradiation of solar panels and found that they withstood high doses, such as 20 Mrad, the panels having aged and the energy output having become lower but steady. The response of the solar cells to high levels of radiation caused Gammaster to attempt to use this effect to serve as a check on the operating status of its large 60Co gamma irradiation facility. During γ-irradiation a potential is generated in a p-n silicon solar cell which can be made to drive ancillary equipment. For example, the current from the solar cell can be fed to a pen recorder to assist in process control. The pen recorder can, for example, also act as an automatic logbook by recording the irradiation times. The sensitivity of a cell is such that changes in absorption between homogeneously and inhomogeneously filled containers are clearly shown on the recorder sheets. All source movements are visible, and the timer setting and the number of containers treated, etc. can be monitored. Such a system provides a reliable additional process control at low cost and requests little maintenance. (author)

  18. Measuring temperatures on absorbers irradiated in a solar furnace by flash assisted multi-wavelength pyrometry (FAMP)

    Tschudi, H.R.; Schubnell, M.; Muller, Chr. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-03-01

    In a solar furnace, the sample is heated by concentrated solar radiation of which a certain fraction will be reflected. If the thermal (Planckian) emission of the sample shall be used to measure its surface temperature one has to either separate the thermally emitted from the reflected radiation or to make sure that the reflected solar radiation is negligible compared to the emitted thermal radiation. Furthermore, the accuracy of radiation thermometry significantly relies on an accurate knowledge of the sample emittance which generally depends on wavelength as well as on temperature. In this paper, we propose a multiwavelength analysis for the separation of emitted and reflected radiation and the use of an additional flash to probe the spectral emittance. We first outline the basic ideas and discuss their limitations. We then show experimental and numerical results and add some comments addressing the possibility of avoiding the need for a flash. (authors)

  19. Deep absorbing porphyrin small molecule for high-performance organic solar cells with very low energy losses.

    Gao, Ke; Li, Lisheng; Lai, Tianqi; Xiao, Liangang; Huang, Yuan; Huang, Fei; Peng, Junbiao; Cao, Yong; Liu, Feng; Russell, Thomas P; Janssen, René A J; Peng, Xiaobin

    2015-06-17

    We designed and synthesized the DPPEZnP-TEH molecule, with a porphyrin ring linked to two diketopyrrolopyrrole units by ethynylene bridges. The resulting material exhibits a very low energy band gap of 1.37 eV and a broad light absorption to 907 nm. An open-circuit voltage of 0.78 V was obtained in bulk heterojunction (BHJ) organic solar cells, showing a low energy loss of only 0.59 eV, which is the first report that small molecule solar cells show energy losses X-ray diffraction, resonant soft X-ray scattering, and transmission electron microscopy under different fabrication conditions. PMID:26035342

  20. Relaxation Between Bright Optical Wannier Excitons in Perovskite Solar Absorber CH$_3$NH$_3$PbI$_3$

    Nanguneri, Ravindra; Parkhill, John

    2014-01-01

    We study the light-absorbing states of the mixed-halide perovskite CH$_{3}$NH$_{3}$PbI$_2$Cl and tri-iodide perovskite CH$_{3}$NH$_{3}$PbI$_3$ with density functional and many-body calculations to explain the desirable photovolatic features of these materials. The short-lived electron-hole bound states produced in this photovoltaic material are of halide to lead electron transfer character, with a Wannier-type exciton. Bethe-Salpeter (GW+BSE) calculations of the absorption cross section revea...

  1. Improvement of the efficiency of triple junction n–i–p solar cells with hot-wire CVD proto- and microcrystalline silicon absorber layers

    Stolk, R.L.; Li, H. B. T.; Franken, R.H.; Schuttauf, J.A.; van der Werf, C.H.M.; J.K. Rath; Schropp, R.E.I.

    2008-01-01

    Hot-wire chemical vapour deposition (HWCVD) was applied for the deposition of intrinsic protocrystalline (proto-Si:H) and microcrystalline silicon (μc-Si:H) absorber layers in thin film solar cells. For a single junction μc-Si:H n–i–p cell on a Ag/ZnO textured back reflector (TBR) with a 2.0 μm i-layer, an 8.5% efficiency was obtained, which showed to be stable after 750 h of light-soaking. The short-circuit current density (Jsc) of this cell was 23.4 mA/cm2, with a high open-circuit voltage ...

  2. Spray-deposited CuIn1-xGaxSe2 solar cell absorbers: Influence of spray deposition parameters and crystallization promoters

    To produce smooth, crack-free, and highly crystalline absorber layers are the main challenges in the fabrication of thin film solar cells using nanoparticle-based solution-processing technologies. In this work, we report on the optimization of the spray deposition parameters to produce highly homogeneous CuIn1-xGaxS2 thin films with controlled thickness using nanoparticle-based inks. We further explore the use of inorganic ligand exchange strategies to introduce metal ions able to promote crystallization during the selenization of the layers, removing structural defects and grain boundaries that potentially act as recombination centers. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Spray-deposited CuIn{sub 1-x}Ga{sub x}Se{sub 2} solar cell absorbers: Influence of spray deposition parameters and crystallization promoters

    Carrete, Alex; Placidi, Marcel; Shavel, Alexey [Catalonia Institute for Energy Research - IREC, Sant Adria del Besos, Barcelona (Spain); Perez-Rodriguez, Alejandro [Catalonia Institute for Energy Research - IREC, Sant Adria del Besos, Barcelona (Spain); IN2UB, Departament d' Electronica, Universitat de Barcelona (Spain); Cabot, Andreu [Catalonia Institute for Energy Research - IREC, Sant Adria del Besos, Barcelona (Spain); Institucio Catalana de Recerca i Estudis Avancats - ICREA, Barcelona (Spain)

    2015-01-01

    To produce smooth, crack-free, and highly crystalline absorber layers are the main challenges in the fabrication of thin film solar cells using nanoparticle-based solution-processing technologies. In this work, we report on the optimization of the spray deposition parameters to produce highly homogeneous CuIn{sub 1-x}Ga{sub x}S{sub 2} thin films with controlled thickness using nanoparticle-based inks. We further explore the use of inorganic ligand exchange strategies to introduce metal ions able to promote crystallization during the selenization of the layers, removing structural defects and grain boundaries that potentially act as recombination centers. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Mechanical properties of hybrid organic-inorganic CH3NH3BX3 (B = Sn, Pb; X = Br, I perovskites for solar cell absorbers

    Jing Feng

    2014-08-01

    Full Text Available The crystal structures, elastic and anisotropic properties of CH3NH3BX3 (B = Sn, Pb; X = Br, I compounds as solar cell absorber layers are investigated by the first-principles calculations. The type and strength of chemical bond B-X are found to determine the elastic properties. B-X bonds and the organic cations are therefore crucial to the functionalities of such absorbers. The bulk, shear, Young's modulus ranges from 12 to 30 GPa, 3 to 12 GPa, and 15 to 37 GPa, respectively. Moreover, the interaction among organic and inorganic ions would have negligible effect for elastic properties. The B/G and Poisson's ratio show it would have a good ductile ability for extensive deformation as a flexible/stretchable layer on the polymer substrate. The main reason is attributed to the low shear modulus of such perovskites. The anisotropic indices AU, AB AG, A1, A2, and A3 show ABX3 perovskite have very strong anisotropy derived from the elastic constants, chemical bonds, and symmetry.

  5. Correlation of structure parameters of absorber layer with efficiency of Cu(In, Ga)Se2 solar cell

    Balboul, M. R.; Schock, H. W.; Fayak, S. A.; El-Aal, A. Abdel; Werner, J. H.; Ramadan, A. A.

    2008-08-01

    Polycrystalline Cu(In, Ga)Se2 with Ga-content x=Ga/(In+Ga) ranging from 0.0 (CuInSe2) to 1.0 (CuGaSe2) in heterojunction thin film solar cells were grown by multi-source evaporation. Solar cells with a highest efficiency of η=15.3% need a composition of x≈0.2. At this composition, the c/ a ratio of the lattice constants for the tetragonal lattice equals c/ a=2, indicating ideal tetragonality. These results suggest that low electronic defect densities occur at x≈0.2, due to the smallest possible crystallographic distortion of the tetragonal lattice at this composition. Cells with high efficiencies require grain sizes above 145 nm and a high preferred orientation (P204/P220 pole density ratio) for the grains.

  6. Correlation of structure parameters of absorber layer with efficiency of Cu(In,Ga)Se{sub 2} solar cell

    Balboul, M.R.; Fayak, S.A. [National Center for Radiation Research and Technology (NCRRT), Nasr City, Cairo (Egypt); Schock, H.W.; Werner, J.H. [University of Stuttgart, Institute of Physical Electronics (IPE), Stuttgart (Germany); El-Aal, A.A.; Ramadan, A.A. [Faculty of Science, Helween University, Department of Physics, Cairo (Egypt)

    2008-08-15

    Polycrystalline Cu(In,Ga)Se{sub 2} with Ga-content x=Ga/(In+Ga) ranging from 0.0 (CuInSe{sub 2}) to 1.0 (CuGaSe{sub 2}) in heterojunction thin film solar cells were grown by multi-source evaporation. Solar cells with a highest efficiency of {eta}=15.3% need a composition of x{approx}0.2. At this composition, the c/a ratio of the lattice constants for the tetragonal lattice equals c/a=2, indicating ideal tetragonality. These results suggest that low electronic defect densities occur at x{approx}0.2, due to the smallest possible crystallographic distortion of the tetragonal lattice at this composition. Cells with high efficiencies require grain sizes above 145 nm and a high preferred orientation (P{sub 204}/P{sub 220} pole density ratio) for the grains. (orig.)

  7. Rugometric and Microtopographic Inspection of Cr–Cr2O3 Cermet Solar Absorbers

    Manuel F. M. Costa

    2006-12-01

    Full Text Available The development of new efficient and cost effective solar energy collectors and converters either quantum or thermal attracts great attention and effort in a number of research laboratories all over the world. Cr–Cr2O3 cermet PVD coatings can be successfully employed in thermal converters. Their energy conversion efficiency depends on their chemical and physical structural characteristics and related optical properties like reflectance, emittance, solar light absorption, or absorptance and transmittance. Parameters such as roughness and topographic characteristics of the produced coatings will greatly influence their relevant optical properties. A careful evaluation of the coatings' roughness and their microtopographic inspection is fundamental. The Cr–Cr2O3 cermet coatings sputter deposited on cooper and aluminium shows similar absorption (92% but the first ones present a better emittance and higher waviness (over 30% with similar roughness. In comparison with commercially available solar panels with a slightly better absorption but worse emittance our coatings have a much lower waviness (∼150% and roughly 50% higher roughness.

  8. Microstructure and spectral selectivity of Mo-Al2O3 solar selective absorbing coatings after annealing

    Mo, Al2O3 single layer, Mo-Al2O3 granular cermet layer, Mo/Al2O3 tandem and an optimized Mo-Al2O3 multilayer coating with a double cermet layer configuration were deposited on stainless steel substrates by magnetron sputtering technique. The samples were annealed in vacuum at different temperatures ranging from 350 deg. C to 1000 deg. C for 2-5 h to evaluate their thermal stability. The spectral absorbance and thermal emissivity for the multi-layer selective coatings in the region of 1.3-25 μm were 0.91-0.93 and 0.19-0.27, respectively, depending on heat treatment temperature. Increasing annealing temperature has more obvious influence on the rise of emissivity than the drop of spectral absorbance. The microstructure, surface morphology, composition distribution and diffusion for various films before and after high temperature aging were investigated employing scanning electronic microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Fe2O3, as a diffusion barrier between Mo layer and SS substrate, effectively holds back the presence of Mo2C and Fe2MoC complex phases. Al2O3 is a stable phase even at 1000 deg. C for 3 h. However, defects such as widened boundaries, cracks and holes, which could appear in Al2O3 layer when heated at higher temperature than 650 deg. C, will provide the paths of Mo diffusion. Two diffusion modes of Mo, including inner self-congregation of Mo inside the cermet layer and Mo infiltration through the Al2O3 layer in Mo/Al2O3 tandem at 800 deg. C for 5 h, were observed after annealing

  9. The formation of CuInSe{sub 2}-based thin-film solar cell absorbers from alternative low-cost precursors

    Jost, S.

    2008-01-18

    This work deals with real-time investigations concerning the crystallisation process of CuInSe{sub 2}-based thin-film solar cell absorbers while annealing differently produced and composed ''low-cost'' precursors. Various types of precursors have been investigated concerning their crystallisation behaviour. Three groups of experiments have been performed: (i) Investigations concerning the crystallisation process of the quaternary chalcopyrite Cu(In,Al)Se{sub 2} and Cu(In,Al)S{sub 2}, (ii) investigations concerning the formation process of the compound semiconductor CuInSe{sub 2} from electroplated precursors, and (iii) investigations concerning the crystallisation of Cu(In,Ga)Se{sub 2} using precursors with thermally evaporated indium. A specific sample surrounding has been constructed, which enables to perform time-resolved angle-dispersive X-ray powder diffraction experiments during the annealing process of precursor samples. A thorough analysis of subsequently recorded diffraction patterns using the Rietveld method provides a detailed knowledge about the semiconductor crystallisation process while annealing. Based on these fundamental investigations, conclusions have been drawn concerning an adaptation of the precursor deposition process in order to optimise the final solar cell results. The investigations have shown, that one class of electroplated precursors shows a crystallisation behaviour identical to the one known for vacuum-deposited precursors. The investigations concerning the crystallisation process of the quaternary chalcopyrite Cu(In,Al)Se{sub 2} revealed, that the chalcopyrite forms from the ternary selenide (Al,In){sub 2}Se{sub 3} and Cu{sub 2}Se at elevated process temperatures. This result is used to explain the separation of the absorber layer into an aluminum-rich and an indium-rich chalcopyrite phase, which has been observed at processed Cu(In,Al)Se{sub 2} absorbers from several research groups. In addition, differences

  10. A numerical model for pressure drop and flow distribution in a solar collector with U-connected absorber pipes

    Bava, Federico; Furbo, Simon

    2016-01-01

    pressure drop across the collector. The model was developed in Matlab and is based on correlations found in literature for both friction losses and local losses, and was compared in terms of overall pressure drop against experimental measurements carried out on an Arcon Sunmark HT 35/10 solar collector at...... different flow rates and temperatures for water and water/propylene glycol mixture. For collector pressure drops higher than 1.4 kPa, the relative difference between the model and measurements was within 5% for water and 7% for water/propylene glycol mixture. For lower pressure drops the relative difference...

  11. A thermal-optical analysis comparison between symmetric tubular absorber compound parabolic concentrating solar collector with and without envelope

    Equations describing the heat transfer in symmetric, compound parabolic concentrating solar collectors (CPCs) with and without envelope have been established. The model takes into account the non linear behavior of these two systems. A theoretical numerical model has been developed to outline the effect of the envelope on the thermal and optical performance of CPCs. The effects of the flow rate, the plate length, the selective coating, etc. are studied. The over-all thermal loss coefficient and the enclosure absorption factor for both types are defined. It is found that the efficient configuration has an envelope. Theoretical computed values are in good agreement with the experimental values published in the literature. (author)

  12. Extracting Information about the Electronic Quality of Organic Solar-Cell Absorbers from Fill Factor and Thickness

    Kaienburg, Pascal; Rau, Uwe; Kirchartz, Thomas

    2016-08-01

    Understanding the fill factor in organic solar cells remains challenging due to its complex dependence on a multitude of parameters. By means of drift-diffusion simulations, we thoroughly analyze the fill factor of such low-mobility systems and demonstrate its dependence on a collection coefficient defined in this work. We systematically discuss the effect of different recombination mechanisms, space-charge regions, and contact properties. Based on these findings, we are able to interpret the thickness dependence of the fill factor for different experimental studies from the literature. The presented model provides a facile method to extract the photoactive layer's electronic quality which is of particular importance for the fill factor. We illustrate that over the past 15 years, the electronic quality has not been continuously improved, although organic solar-cell efficiencies increased steadily over the same period of time. Only recent reports show the synthesis of polymers for semiconducting films of high electronic quality that are able to produce new efficiency records.

  13. CuSbS2: a promising semiconductor photo-absorber material for quantum dot sensitized solar cells.

    Liu, Zhifeng; Huang, Jiajun; Han, Jianhuan; Hong, Tiantian; Zhang, Jing; Liu, Zhihua

    2016-06-22

    A facile, low-cost, simple solution-based process for preparing novel promising chalcostibite CuSbS2 sensitized ZnO nanorod arrays, and the application of these as photoanodes of semiconductor quantum dot sensitized inorganic-organic solar cells (QDSSCs) is reported for the first time. ZnO/CuSbS2 nanofilms were designed and prepared through a simple successive ionic layer adsorption and reaction (SILAR) method and heat treatment process by employing ZnO nanorods as reactive templates. Novel efficient QDSSCs based on the ZnO/CuSbS2 nanofilms plus a solid electrolyte of poly(3-hexylthiophene) (P3HT) were formed, and a power conversion efficiency of 1.61% was achieved. The excellent photoelectric performance is attributed to the improved light absorption efficiency, widened light absorption region, ideal band gap value, and high speed electron injection and transportation. The results demonstrate that a novel ternary sensitizer (I-V-VI2) can be synthesized via a low-cost method as described here and has great promising potential as a sensitizer in solar cells. PMID:27297190

  14. Study of durability of (molybdenum-copper)-black coatings in relation to their use as solar selective absorbers

    Yousif, K.M.; Smith, B.E. (Brunel Univ., Uxbridge (United Kingdom)); Jeynes, C. (Surrey Univ., Guildford (United Kingdom). Dept. of Electronic and Electrical Engineering)

    1994-08-01

    In this work (Mo-Cu)-black coatings on Ni-plated Cu substrates have been prepared by electrodeposition. Their stability and durability has been investigated. The durability tests were carried out in two forms; accelerated ageing, and weathering. Reflectance measurements were used to evaluate both solar absorptance ([alpha]) and thermal emittance ([epsilon]) of the coatings. The coatings have been characterised before and after durability testing, using spectrophotometry together with other techniques, such as electron microscopy, X-rays, and ion beam. The main degradation modes of these coatings are loss of water, diffusion of metal atoms, and oxidation. (Mo-Cu)-black coatings undergo some changes in [alpha] and [epsilon] outdoor ageing. (Author)

  15. Origin of High Electronic Quality in Solar Cell Absorber CH3NH3PbI3

    Yin, Wanjian; Shi, Tingting; Wei, Suhua; Yan, Yanfa

    Thin-film solar cells based on CH3NH3PbI3 halide perovskites have recently shown remarkable performance. First-principle calculations and molecular dynamic simulations show that the structure of pristine CH3NH3PbI3 is much more disordered than the inorganic archetypal thin-film semiconductor CdTe. However, the structural disorders from thermal fluctuation, point defects and grain boundaries introduce rare deep defect states within the bandgaps; therefore, the material has high electronic quality. We have further shown that this unusually high electronic quality is attributed to the unique electronic structures of halide perovskite: the strong coupling between cation lone-pair Pb s orbitals and anion p orbitals and the large atomic size of constitute cation atoms. We further found that although CH3NH3PbI3 GBs do not introduce a deep gap state, the defect level close to the VBM can still act as a shallow hole trap state. Cl and O can spontaneously segregate into GBs and passivate those defect levels and deactivate the trap state.

  16. Growth of Cu{sub 2}ZnSnS{sub 4} absorber layer on flexible metallic substrates for thin film solar cell applications

    Yazici, Sebnem [Department of Physics, Izmir Institute of Technology, Urla, Izmir 35430 (Turkey); Olgar, Mehmet Ali [Department of Physics, Karadeniz Technical University, Trabzon (Turkey); Akca, Fatime Gulsah; Cantas, Ayten; Kurt, Metin; Aygun, Gulnur; Tarhan, Enver [Department of Physics, Izmir Institute of Technology, Urla, Izmir 35430 (Turkey); Yanmaz, Ekrem [Department of Physics, Karadeniz Technical University, Trabzon (Turkey); Ozyuzer, Lutfi, E-mail: ozyuzer@iyte.edu.tr [Department of Physics, Izmir Institute of Technology, Urla, Izmir 35430 (Turkey)

    2015-08-31

    In this work, Cu{sub 2}ZnSnS{sub 4} (CZTS) absorber layers were fabricated using a two-stage process. Sequentially deposited Cu–Zn–Sn thin film layers on metallic foils were annealed in an Ar + S{sub 2(g)} atmosphere. We aimed to investigate the role of flexible titanium and molybdenum foil substrates in the growth mechanism of CZTS thin films. The Raman spectra and X-ray photoelectron spectroscopy analyses of the sulfurized thin films revealed that, except for the presence of Sn-based secondary phases, nearly pure CZTS thin films were obtained. Additionally, the intense and sharp X-ray diffraction peak from the (112) plane provided evidence of good crystallinity. Electron dispersive spectroscopy analysis indicated sufficient sulfur content but poor Zn atomic weight percentage in the films. Absorption and band-gap energy analyses were carried out to confirm the suitability of CZTS thin films as the absorber layer in solar cell applications. Hall effect measurements showed the p-type semiconductor behavior of the CZTS samples. Moreover, the back contact behavior of these metallic flexible substrates was investigated and compared. We detected formation of cracks in the CZTS layer on the molybdenum foils, which indicates the incompatibility of molybdenum's thermal expansion coefficient with the CZTS structure. We demonstrated the application of the magnetron sputtering technique for the fabrication of CZTS thin films on titanium foils having lightweight, flexible properties and suitable for roll-to-roll manufacturing for high throughput fabrication. Titanium foils are also cost competitive compared to molybdenum foils. - Highlights: • Growth of CZTS layer for thin film solar cell applications • CZTS growth on metallic flexible foil substrates by magnetron sputtering technique • Lightweight and flexible substrate is feasible for roll-to-roll manufacturing. • Crack formation on Mo foil substrate due to mismatch of CTE between Mo and CZTS • Ti foil is

  17. Review on first-principles study of defect properties of CdTe as a solar cell absorber

    Yang, Ji-Hui; Yin, Wan-Jian; Park, Ji-Sang; Ma, Jie; Wei, Su-Huai

    2016-08-01

    CdTe is one of the leading materials for high-efficiency, low-cost, and thin-film solar cells. In this work, we review the recent first-principles study of defect properties of CdTe and present that: (1) When only intrinsic defects are present, p-type doping in CdTe is weak and the hole density is low due to the relatively deep acceptor levels of Cd vacancy. (2) When only intrinsic defects present, the dominant non-radiative recombination center in p-type CdTe is T{e}Cd2+, which limits the carrier lifetime to be around 200 ns. (3) Extrinsic p-type doping in CdTe by replacing Te with group V elements generally will be limited by the formation of AX centers. This could be overcome through a non-equilibrium cooling process and the hole density can achieve {10}17 {{{cm}}}-3. However, the long-term stability will be a challenging issue. (4) Extrinsic p-type doping by replacing Cd with alkaline group I elements is limited by alkaline interstitials and a non-equilibrium cooling process can efficiently enhance the hole density to the order of {10}17 {{{cm}}}-3. (5) Cu and Cl treatments are discussed. In bulk CdTe, Cu can enhance p-type doping, but Cl is found to be unsuitable for this. Both Cu and Cl show segregation at grain boundaries, especially at those with Te–Te wrong bonds. (6) External impurities are usually incorporated by diffusion. Therefore, the diffusion processes in CdTe are investigated. We find that cation interstitial (Nai, Cui) diffusion follows relatively simple diffusion paths, but anion diffusion (Cli, Pi) follows more complicated paths due to the degenerated defect wavefunctions.

  18. Review on First-Principles Study of Defect Properties of CdTe as a Solar Cell Absorber

    Yang, Ji-Hui; Yin, Wan-Jian; Park, Ji-Sang; Ma, Jie; Wei, Su-Huai

    2016-08-01

    CdTe is one of the leading materials for high-efficiency, low-cost, and thin-film solar cells. In this work, we review the recent first-principles study of defect properties of CdTe and present that: (1) When only intrinsic defects are present, p-type doping in CdTe is weak and the hole density is low due to the relatively deep acceptor levels of Cd vacancy. (2) When only intrinsic defects present, the dominant non-radiative recombination center in p-type CdTe is Te-2+/Cd, which limits the carrier lifetime to be around 200 ns. (3) Extrinsic p-type doping in CdTe by replacing Te with group V elements generally will be limited by the formation of AX centers. This could be overcome through a non-equilibrium cooling process and the hole density can achieve 10^17 cm-3. However, the long-term stability will be a challenging issue. (4) Extrinsic p-type doping by replacing Cd with alkaline group I elements is limited by alkaline interstitials and a non-equilibrium cooling process can efficiently enhance the hole density to the order of 10^17 cm-3. (5) Cu and Cl treatments are discussed. In bulk CdTe, Cu can enhance p-type doping, but Cl is found to be unsuitable for this. Both Cu and Cl show segregation at grain boundaries, especially at those with Te-Te wrong bonds. (6) External impurities are usually incorporated by diffusion. Therefore, the diffusion processes in CdTe are investigated. We find that cation interstitial (Nai, Cui) diffusion follows relatively simple diffusion paths, but anion diffusion (Cli, Pi) follows more complicated paths due to the degenerated defect wavefunctions.

  19. High-temperature hydrogenation of pure and silver-decorated titanate nanotubes to increase their solar absorbance for photocatalytic applications

    Plodinec, Milivoj [Ruđer Bošković Institute, Bijenička 54, HR-1002 Zagreb (Croatia); Gajović, Andreja, E-mail: gajovic@irb.hr [Ruđer Bošković Institute, Bijenička 54, HR-1002 Zagreb (Croatia); Jakša, Gregor; Žagar, Kristina; Čeh, Miran [Institute Jožef Stefan, Jamova 39, 1000 Ljubljana (Slovenia)

    2014-04-05

    Graphical abstract: The aim of the work is to study how annealing in a reducing atmosphere of titanate nanotubes (TiNT) and Ag decorated titanate nanotubes (TiNT@Ag) influenced on their structure, morphology, phase transitions, UV–ViS-NIR absorbance and photocatalytic activity. An increase of photocatalytic activity after a heat treatment in a reducing atmosphere was observed in the TiNT and TiNT@Ag. We found that the hydrogenated TiNT@Ag samples (TiNT@Ag-HA) had a two-times higher photodegradation impact on the caffeine than the TiNT samples, which is a consequence of the increased absorption of visible light and the synergetic effects between the silver and the TiO{sub 2} nanoparticles that increase the efficiency of the formation of electron–hole pairs and the charge transfer to the surface of the nanoparticles. -- Highlights: • Titanate nanotubes with and without Ag nanoparticles were hydrogenated at 550 °C. • TiO{sub 2} nanostructures obtained by hydrogenation have core–shell structure. • Hydrogenated samples show absorption in the visible spectral region. • Hydrogenated Ag decorated sample show stronger absorption in visible than in UV. • Photocatalytic efficiency is improved by hydrogenation and by Ag nanoparticles. -- Abstract: Titanate nanotubes (TiNTs) and silver-decorated titanate nanotubes (TiNTs@Ag) were synthesized using the hydrothermal method. In the decorated nanotubes the silver particles were obtained by the photoreduction of AgNO{sub 3} under UV light. Pure and Ag-decorated nanotubes were high-temperature heat treated at 550 °C in a hydrogen atmosphere and the “core–shell”-structured TiO{sub 2} nanoparticles were formed. For the structural characterization of all the titanate nanostructures we used conventional and analytical transmission electron microscopy (TEM) techniques, X-ray diffraction (XRD) and Raman spectroscopy. The Ag-decorated titanate nanostructures were additionally studied by X-ray photo

  20. Behavior of Electrochemically Prepared CuInSe{sub 2} as Photovoltaic Absorber in thin Film Solar Cells; Comportamiento del CuInSe{sub 2} Basado en Precursores Electrodepositados como Absorbente Fotovoltaico en Celulas Solares de Lamina Delgada

    Guillen, C.; Martinez, M. A.; Dona, J. M.; Herrero, J.; Gutierrez, M. T. [Ciemat.Madrid (Spain)

    2000-07-01

    Two different objective have been pursued in the present investigation: (1) optimization of the CuInSe{sub 2} preparation parameters from electrodeposited precursors, and (2) evaluation of their photovoltaic behavior by preparing and enhancing Mo/CuInSe{sub 2}/CdS/TCO devices. When Cu-In-Se precursors are directly electrodeposited, the applied potential fit is essential to improve the photovoltaic performance. Suitable absorbers have been also obtained by evaporing an In layer onto electrodeposited Cu-Se precursors. In this case, the substrate temperature during evaporation determines the CuInSe{sub 2} quality. Similar results have been reached by substituting typical Mo-Coated glass substrates by flexible Mo foils. Different TCO tested (ZnO and ITO) have been found equivalent as front electrical contact in the devices. Solar cell performance can be improved by annealing in air at 200 degree centigree. (Author) 46 refs.

  1. Deposition of ultra thin CuInS2 absorber layers by ALD for thin film solar cells at low temperature (down to 150 °C)

    Two new processes for the atomic layer deposition of copper indium sulfide (CuInS2) based on the use of two different sets of precursors are reported. Metal chloride precursors (CuCl, InCl3) in combination with H2S imply relatively high deposition temperature (Tdep = 380 °C), and due to exchange reactions, CuInS2 stoechiometry was only achieved by depositing In2S3 layers on a CuxS film. However, the use of acac- metal precursors (Cu(acac)2, In(acac)3) allows the direct deposition of CuInS2 at temperature as low as 150 °C, involving in situ copper-reduction, exchange reaction and diffusion processes. The morphology, crystallographic structure, chemical composition and optical band gap of thin films were investigated using scanning electronic microscope, x-ray diffraction under grazing incidence conditions, x-ray fluorescence, energy dispersive spectrometry, secondary ion mass spectrometry, x-ray photoelectron spectroscopy and UV–vis spectroscopy. Films were implemented as ultra-thin absorbers in a typical CIS-solar cell architecture and allowed conversion efficiencies up to 2.8%. (paper)

  2. PERFORMANCE EVALUATION OF SOLAR COLLECTORS USING A SOLAR SIMULATOR

    M. Norhafana; Ahmad Faris Ismail; Z. A. A. Majid

    2015-01-01

    Solar water heating systems is one of the applications of solar energy. One of the components of a solar water heating system is a solar collector that consists of an absorber. The performance of the solar water heating system depends on the absorber in the solar collector. In countries with unsuitable weather conditions, the indoor testing of solar collectors with the use of a solar simulator is preferred. Thus, this study is conducted to use a multilayered absorber in the solar collector of...

  3. Growth of Cu2ZnSnS4 Nanocrystallites on TiO2 Nanorod Arrays as Novel Extremely Thin Absorber Solar Cell Structure via the Successive-Ion-Layer-Adsorption-Reaction Method.

    Wang, Zhuoran; Demopoulos, George P

    2015-10-21

    Cu2ZnSnS4 (CZTS) is an environmentally benign semiconductor with excellent optoelectronic properties that attracts a lot of interest in thin film photovoltaics. In departure from that conventional configuration, we fabricate and test a novel absorber-conductor structure featuring in situ successive-ion-layer-adsorption-reaction (SILAR)-deposited CZTS nanocrystallites as a light absorber on one-dimensional TiO2 (rutile) nanorods as an electron conductor. The effectiveness of the nanoscale heterostructure in visible light harvesting and photoelectron generation is demonstrated with an initial short circuit current density of 3.22 mA/cm(2) and an internal quantum efficiency of ∼60% at the blue light region, revealing great potential in developing CZTS extremely thin absorber (ETA) solar cells. PMID:26422062

  4. Sustainable low temperature preparation of Mn3−xCoxO4 (0 ≤ x < 3) spinel oxide colloidal dispersions used for solar absorber thin films

    The preparation of pure crystalline oxide nanoparticles (with controlled composition, size and shape) and formation of stable suspensions free of complex organic precursors was developed and optimized at room temperature (or below 100 °C). This reproducible water and ethanol synthesis and solution stabilization of oxide nanoparticles is based on Mn3−xCoxO4 (0 ≤ x < 3) composition materials. To our knowledge, this is the first study on the complete Mn–Co–O spinel system synthesized at low temperature. The main hydrodynamic parameters, as well as the physical and chemical properties that control the oxide precipitation and nanoparticle size and morphology were characterized in detail for the family end member Mn3O4 and used for the other compositions. X-ray diffraction and Scanning Electron Microscopy images showed the influence of the alkaline solution concentration, pH, temperature and solvent on the nanoparticles properties. Neutron diffraction was used for determining the cationic distribution in two compositions, i.e. CoMn2O4 and MnCo2O4. While the tetrahedral site is mainly occupied by Co2+, four types of cations were determined for the octahedral sites. Zeta potential and rheological measurements were performed to determine the stability region of nanoparticles in aqueous solution. This innovative and low cost process was used to produce homogenous and crystalline metal oxide thin films that can be used as solar absorbers in various applications. Their optical properties were characterized. A second absorption edge, due to cobalt and observed in the visible region, is attributed to an intermediate band gap, which is a very important feature, especially for future solar cells. This sustainable synthesis of oxide nanoparticles and thin film preparation procedure is applicable to other oxide families. - Graphical abstract: Display Omitted - Highlights: • Sustainable low temperature synthesis of oxide nanoparticles. • Stabilization of colloidal

  5. Effect of post-deposition annealing on the growth of Cu2ZnSnSe4 thin films for a solar cell absorber layer

    Babu, G. Suresh; Kishore Kumar, Y. B.; Uday Bhaskar, P.; Sundara Raja, V.

    2008-08-01

    The effect of substrate temperature and post-deposition annealing on the growth and properties of Cu2ZnSnSe4 thin films, a potential candidate for a solar cell absorber layer, is investigated. The substrate temperature (Ts) is chosen to be in the range 523-673 K and the annealing temperature (Tpa) is kept at 723 K. Powder x-ray diffraction (XRD) patterns of as-deposited films revealed that the films deposited at Ts = 523 K and 573 K contain Cu2-xSe as a secondary phase. Single phase, polycrystalline Cu2ZnSnSe4 films are obtained at Ts = 623 K and films deposited at Ts = 673 K have ZnSe as a secondary phase along with Cu2ZnSnSe4. Direct band gap of as-deposited CZTSe films is found to lie between 1.40 eV and 1.65 eV depending on Ts. XRD patterns of post-deposition annealed films revealed that the films deposited at Ts = 523-623 K are single phase CZTSe and films deposited at Ts = 673 K still contain ZnSe secondary phase. CZTSe films are found to exhibit kesterite structure with the lattice parameters a = 0.568 nm and c = 1.136 nm. Optical absorption studies of post-deposition annealed films show that there is a slight increase in the band gap on annealing, due to decrease in the Cu content. Electrical resistivity of the films is found to lie in the range 0.02-2.6 Ω cm depending on Ts.

  6. 涂料外饰面的太阳辐射吸收性能测试方法分析%ANALYSIS ON EXPERIMENTAL METHOD OF COATINGS' SOLAR ABSORBING PERFORMANCE

    董海荣; 祁少明; 麻建锁

    2012-01-01

    通过对室外综合温度的分析,介绍一种测试涂料外饰面太阳辐射吸收系数的间接方法,并通过对测试数据的分析与总结,验证该间接测试方法的可行性,结果表明,采用深色涂料外饰面的建筑吸收的太阳辐射热较浅颜色的多,而涂料外饰面层的粗糙度对建筑吸收太阳辐射热影响不明显.%Indirect method was introduced. The results show that this indirect method is feasible and some conclusions are put forward that buildings with coatings in dark color absorb more solar radiation than that in light color and the difference of solar radiation absorbed by the different roughness of coatings is not obvious. The references are provided for testing absorption coefficient of solar radiation of new coatings and the selection of external decorative materials in architectural design.

  7. Thermal Stress Analysis of Two-stage Reflective Tower Solar Heat Absorber%二次反射塔式太阳能吸热器热应力分析

    张晨; 马超; 赵云云; 李凤娟; 张晓燕; 杨晓峰

    2015-01-01

    Solar energy heat absorber is one of the most important equipment in tower thermal solar energy systems ,the heat pipe and the joint of heat pipe and mother tube are the thermal stress concentration. This paper analyze thermal stress of these parts in heat absorber. Numerical simulation is used to get the change of the thermal stress of different bend with the temperature change. The results prove that the temperature difference of molten salt is the main factor which influences the thermal stress distribution can be got.%太阳能吸热器是塔式光热太阳能发电系统中最重要的设备之一,吸热器内吸热管、吸热管与母管连接处都是热应力产生的集中点,文中对吸热器这几个部位进行热应力分析,通过数值模拟得出不同弯头热应力随温度的变化情况,以及熔盐温差是影响热应力分布的主要因素。

  8. Framework to predict optimal buffer layer pairing for thin film solar cell absorbers: A case study for tin sulfide/zinc oxysulfide

    Mangan, Niall M.; Brandt, Riley E.; Steinmann, Vera; Jaramillo, R.; Poindexter, Jeremy R.; Chakraborty, Rupak; Buonassisi, Tonio [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Yang, Chuanxi; Park, Helen Hejin; Zhao, Xizhu; Gordon, Roy G. [Harvard University, Cambridge, Massachusetts 02138 (United States)

    2015-09-21

    An outstanding challenge in the development of novel functional materials for optoelectronic devices is identifying suitable charge-carrier contact layers. Herein, we simulate the photovoltaic device performance of various n-type contact material pairings with tin(II) sulfide (SnS), a p-type absorber. The performance of the contacting material, and resulting device efficiency, depend most strongly on two variables: conduction band offset between absorber and contact layer, and doping concentration within the contact layer. By generating a 2D contour plot of device efficiency as a function of these two variables, we create a performance-space plot for contacting layers on a given absorber material. For a simulated high-lifetime SnS absorber, this 2D performance-space illustrates two maxima, one local and one global. The local maximum occurs over a wide range of contact-layer doping concentrations (below 10{sup 16 }cm{sup −3}), but only a narrow range of conduction band offsets (0 to −0.1 eV), and is highly sensitive to interface recombination. This first maximum is ideal for early-stage absorber research because it is more robust to low bulk-minority-carrier lifetime and pinholes (shunts), enabling device efficiencies approaching half the Shockley-Queisser limit, greater than 16%. The global maximum is achieved with contact-layer doping concentrations greater than 10{sup 18 }cm{sup −3}, but for a wider range of band offsets (−0.1 to 0.2 eV), and is insensitive to interface recombination. This second maximum is ideal for high-quality films because it is more robust to interface recombination, enabling device efficiencies approaching the Shockley-Queisser limit, greater than 20%. Band offset measurements using X-ray photoelectron spectroscopy and carrier concentration approximated from resistivity measurements are used to characterize the zinc oxysulfide contacting layers in recent record-efficiency SnS devices. Simulations representative of these

  9. Framework to predict optimal buffer layer pairing for thin film solar cell absorbers: A case study for tin sulfide/zinc oxysulfide

    An outstanding challenge in the development of novel functional materials for optoelectronic devices is identifying suitable charge-carrier contact layers. Herein, we simulate the photovoltaic device performance of various n-type contact material pairings with tin(II) sulfide (SnS), a p-type absorber. The performance of the contacting material, and resulting device efficiency, depend most strongly on two variables: conduction band offset between absorber and contact layer, and doping concentration within the contact layer. By generating a 2D contour plot of device efficiency as a function of these two variables, we create a performance-space plot for contacting layers on a given absorber material. For a simulated high-lifetime SnS absorber, this 2D performance-space illustrates two maxima, one local and one global. The local maximum occurs over a wide range of contact-layer doping concentrations (below 1016 cm−3), but only a narrow range of conduction band offsets (0 to −0.1 eV), and is highly sensitive to interface recombination. This first maximum is ideal for early-stage absorber research because it is more robust to low bulk-minority-carrier lifetime and pinholes (shunts), enabling device efficiencies approaching half the Shockley-Queisser limit, greater than 16%. The global maximum is achieved with contact-layer doping concentrations greater than 1018 cm−3, but for a wider range of band offsets (−0.1 to 0.2 eV), and is insensitive to interface recombination. This second maximum is ideal for high-quality films because it is more robust to interface recombination, enabling device efficiencies approaching the Shockley-Queisser limit, greater than 20%. Band offset measurements using X-ray photoelectron spectroscopy and carrier concentration approximated from resistivity measurements are used to characterize the zinc oxysulfide contacting layers in recent record-efficiency SnS devices. Simulations representative of these present-day devices suggest

  10. Surface Morphological Studies of Solar Absorber Layer Cu2ZnSnS4 (CZTS) Thin Films by Non-vacuum Deposition Methods

    Chandra Sekhar Kanuru; G.L. Shekar; L. Krishnamurthy; R. Gopal Krishne Urs

    2014-01-01

    The consumption of fossil fuel globally has been enormous and has reached an alarming rate resulting in fast depletion of the available resources and at the same time polluting the environment. Hence there is a growing need to take cognizance of abundant amount of inexpensive energy available in the nature especially solar energy. Development and commercialization of Photovoltaics has been in focus due to its low cost, high absorption coefficient and suitable direct band gap for solar energy ...

  11. 太阳能甲烷重整中催化活性吸收体的表面特性%Surface Properties of the Catalytic Active Absorber for Solar Reforming of Methane

    桑丽霞; 王国瑞; 孙彪; 吴玉庭; 马重芳

    2013-01-01

    Solar CO2 reforming of methane has attracted a great attention because it can realize energy storage of high-temperature heat from concentrated solar radiation and optimal utilization of resources of natural gas.Catalytic active absorber has a key role on absorption of solar energy and reforming of methane and becomes focus of solar reforming of methane research.Catalytic active absorber,Ru/Al2O3/AISI316,Ni/Al2O3 (MgO)/AISI316,were firstly fabricated by using AISI316 metal foam as the matrix.The surface properties of the resulting catalytic active absorber were characterized by means of XRD,H2-TPR and CO2-TPD techniques.Combination of the reactivity behavior of the as-prepared samples in a continuous flow fixed-bed reaction system with a quartz tube reactor,it can be found that the high activity and the long-term stability of Ru/Al2O3/AISI316 foam was unaffected by the components changes of in AISI316 foam matrix during the high temperature reaction.For nickel based catalytic active absorber,the activity for methane reforming of CO2 can be improved by adding the promoter MgO or increasing the Al2O3 coating.Based on the characterization of XRD and H2-TPR,AISI316 foam matrix can enhance the interaction between the Al2O3 coating and the active species Ru or Ni,particularly for Ru/Al2O3/AISI316,the formed Ru-O-Al surface species can lead to the increase of high dispersion of active species.From the peak area of adsorption and desorption behavior,the activating and absorption ability of CO2 on Ru/Al2O3/AISI316 is higher than that of Ni/Al2O3/AISI316,which ascribes to the more active sites on the surface of the catalytic active absorber.%以AISI316泡沫金属为基体为太阳能甲烷重整反应制备出系列Ru基和Ni基催化活性吸收体(Ru/Al2O3/AISI316,Ni/Al2O3 (MgO)/AISI316),着重利用XRD、TPR、TPD和CO2脉冲吸脱附等技术对所制整体式催化剂的表面特性进行了表征和分析.结果表明:以AISI316泡沫金属为基体可增加

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

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

    2014-01-01

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

  13. Preparation and Characterization of Squaraine Dyes containing Mono- and Bis-Anchoring Groups as the Light Absorber in Dye Sensitized Solar Cells

    Graphical abstract: - Highlights: • We aim to enhance charge transfer between squaraine dyes (SQ) and TiO2. • Smaller amounts of SSQ dye is loaded on the TiO2 than the USQ dye. • SSQ shows better electronic coupling with TiO2 than USQ. • The enhanced electronic coupling leads SSQ to show better photovoltaic performance. - Abstract: Enhancing the charge transfer rate in dye sensitized solar cells (DSSCs) is one of the most important criteria determining the cell efficiency. This paper reports a novel strategy for enhancing charge transfer between squaraine dyes and TiO2 by increasing the anchoring number. Symmetrical (SSQ) and unsymmetrical squaraine (USQ) sensitizers with different numbers of anchoring groups in their chromophores are synthesized. SSQ dye containing a bis-anchoring group shows better electronic coupling with TiO2 than the USQ dye with a mono-bridge. This enhanced electronic coupling leads SSQ to exhibit better photovoltaic performance, though smaller amounts of SSQ dye is loaded on the TiO2 than the USQ dye. Under standard global AM 1.5 solar conditions, the optimized SSQ-sensitized solar cells show 7.76 mA cm−2 of short-circuit photocurrent density, 0.62 V of open-circuit voltage, and 0.65 of fill factor (FF), to give overall conversion efficiency of 3.20%, which is approximately 25% higher than the USQ-sensitized solar cells

  14. Bismuth-doped Cu(In,Ga)Se{sub 2} absorber prepared by multi-layer precursor method and its solar cell

    Chantana, Jakapan; Hironiwa, Daisuke; Minemoto, Takashi [Department of Electrical and Electronic Engineering, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577 (Japan); Watanabe, Taichi; Teraji, Seiki; Kawamura, Kazunori [Environment and Energy Research Center, Nitto Denko Corporation, 2-8 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2015-06-15

    Bismuth (Bi)-doped Cu(In,Ga)Se{sub 2} (CIGS) films were prepared by the so-called ''multi-layer precursor method'', obtained by depositing them onto Bi layers with various thicknesses on Mo-coated soda-lime glass (SLG) substrates. Material composition (Cu, In, Ga, and Se) profiles of the CIGS films are almost identical, whereas sodium (Na) is reduced, when Bi thickness is increased. Moreover, the incorporation of Bi into the CIGS film is enhanced with thicker Bi layer. With Bi thickness from 0 to 70 nm, the 2.4-μm-thick CIGS absorbers demonstrate the increase in CIGS grain size, carrier lifetime, and carrier concentration, thus improving their cell performances, especially open-circuit voltage (V{sub OC}). With further increase in Bi thickness of above 70 nm, the CIGS films show the deterioration of CIGS film quality owing to the formation of Bi compounds such as Bi, BiSe, and Bi{sub 4}Se{sub 3}. Consequently, Bi-doped CIGS absorber with thickness of 2.4 μm, prepared with the 70-nm-thick Bi layer on Mo-coated SLG substrate, gives rise to the improvement of photovoltaic performances, especially V{sub OC}. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Acoustic coherent perfect absorbers

    In this paper, we explore the possibility of achieving acoustic coherent perfect absorbers. Through numerical simulations in two dimensions, we demonstrate that the energy of coherent acoustic waves can be totally absorbed by a fluid absorber with specific complex mass density or bulk modulus. The robustness of such absorbing systems is investigated under small perturbations of the absorber parameters. We find that when the resonance order is the lowest and the size of the absorber is comparable to the wavelength in the background, the phenomenon of perfect absorption is most stable. When the wavelength inside both the background and the absorber is much larger than the size of the absorber, perfect absorption is possible when the mass density of the absorber approaches the negative value of the background mass density. Finally, we show that by using suitable dispersive acoustic metamaterials, broadband acoustic perfect absorption may be achieved. (papers)

  16. Low temperature formation of CuIn{sub 1−x}Ga{sub x}Se{sub 2} solar cell absorbers by all printed multiple species nanoparticulate Se + Cu-In + Cu-Ga precursors

    Möckel, Stefan A., E-mail: Stefan.A.Moeckel@FAU.de [Department of Materials Science, Chair of Materials for Electronics and Energy Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Martensstr, 7, 91058 Erlangen (Germany); Wernicke, Tobias; Arzig, Matthias; Köder, Philipp [Department of Materials Science, Chair of Materials for Electronics and Energy Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Martensstr, 7, 91058 Erlangen (Germany); Brandl, Marco [Chair for Crystallography and Structural Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Staudtstr. 3, 91058 Erlangen (Germany); Ahmad, Rameez; Distaso, Monica; Peukert, Wolfgang [Institute of Particle Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Cauerstr. 4, 91058 Erlangen (Germany); Hock, Rainer [Chair for Crystallography and Structural Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Staudtstr. 3, 91058 Erlangen (Germany); Wellmann, Peter J. [Department of Materials Science, Chair of Materials for Electronics and Energy Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Martensstr, 7, 91058 Erlangen (Germany)

    2015-05-01

    In this work an all nanoparticulate precursor for application in Cu(In{sub 1−x}Ga{sub x})Se{sub 2} solar cell absorbers is presented. Binary Cu-In nanoparticles, Cu-Ga powder and elemental Se nanoparticles were mixed in dispersion and deposited on Mo-coated substrates. Research was focused on Cu(In{sub 1−x}Ga{sub x})Se{sub 2} layer formation kinetics, phase composition characterised by differential scanning calorimetry and in-situ X-ray diffraction (XRD). Furthermore phase composition and morphology were studied by ex-situ XRD, Raman spectroscopy and scanning electron microscopy. The results revealed a fast consumption of the precursor and the formation of CuInSe{sub 2} below 340 °C. Binary secondary phases were not observed at any temperature. - Highlights: • All printable precursor for CIGSe • Formation of Ga droplets • Complete consumption below 340 °C.

  17. Low band gap S,N-heteroacene-based oligothiophenes as hole-transporting and light absorbing materials for efficient perovskite-based solar cells

    Qin, Peng

    2014-07-15

    Novel low band gap oligothiophenes incorporating S,N-heteropentacene central units were developed and used as hole-transport materials (HTMs) in solid-state perovskite-based solar cells. In addition to appropriate electronic energy levels, these materials show high photo-absorptivity in the low energy region, and thus can contribute to the light harvesting of the solar spectrum. Solution-processed CH3NH3PbI3-based devices using these HTMs achieved power conversion efficiencies of 9.5-10.5% in comparison with 7.6% obtained by reference devices without HTMs. Photoinduced absorption spectroscopy gave further insight into the charge transfer behavior between photoexcited perovskites and the HTMs. This journal is © the Partner Organisations 2014.

  18. Modification of electron states in CdTe absorber due to a buffer layer in CdTe/CdS solar cells

    Fedorenko, Y. G., E-mail: y.fedorenko@liverpool.ac.uk; Major, J. D.; Pressman, A.; Phillips, L. J.; Durose, K. [Stephenson Institute for Renewable Energy and Department of Physics, School of Physical Sciences, Chadwick Building, University of Liverpool, Liverpool L69 7ZF (United Kingdom)

    2015-10-28

    By application of the ac admittance spectroscopy method, the defect state energy distributions were determined in CdTe incorporated in thin film solar cell structures concluded on ZnO, ZnSe, and ZnS buffer layers. Together with the Mott-Schottky analysis, the results revealed a strong modification of the defect density of states and the concentration of the uncompensated acceptors as influenced by the choice of the buffer layer. In the solar cells formed on ZnSe and ZnS, the Fermi level and the energy position of the dominant deep trap levels were observed to shift closer to the midgap of CdTe, suggesting the mid-gap states may act as recombination centers and impact the open-circuit voltage and the fill factor of the solar cells. For the deeper states, the broadening parameter was observed to increase, indicating fluctuations of the charge on a microscopic scale. Such changes can be attributed to the grain-boundary strain and the modification of the charge trapped at the grain-boundary interface states in polycrystalline CdTe.

  19. Effects of annealing conditions on crystallization of the CZTS absorber and photovoltaic properties of Cu(Zn,Sn)(S,Se){sub 2} solar cells

    Nguyen, Duy-Cuong, E-mail: cuong.nguyenduy@hust.edu.vn [Nano Optoelectronics Laboratory, Advanced Institute for Science and Technology, Hanoi University of Science and Technology, No.1 Dai Co Viet, Hai Ba Trung, Hanoi (Viet Nam); Ito, Seigo [Department of Electrical Engineering and Computer Sciences, Graduate School of Engineering, University of Hyogo, Himeji, Hyogo 671-2280 (Japan); Dung, Dang Viet Anh [School of Chemical Engineering, Hanoi University of Science and Technology, No.1 Dai Co Viet, Hai Ba Trung, Hanoi (Viet Nam)

    2015-05-25

    Highlights: • CZTS films annealed under H{sub 2}S and Se ambient showed a different characterization. • The crystallizing temperature of CZTS films annealed under H{sub 2}S is higher than Se ambient. • Cell parameters of CZTS solar cells annealed Se ambient is better than H{sub 2}S ambient. • 4.94% efficiency of CZTSSe solar cells annealed under Se ambient was obtained. - Abstract: Cu(Zn,Sn)S{sub 2} (CZTS) nanoparticles were synthesized by hot-injection method. Cu(Zn,Sn)(S,Se){sub 2} (CZTSSe) solar cells were fabricated by printing method using CZTS nanocrystallites on molybdenum/glass substrate. The effects of annealing conditions such as temperature and ambient gas on microstructure and photovoltaic properties were investigated. CZTS films annealed in H{sub 2}S ambient shows low crystallinity, being peeled off easily, and poor photovoltaic characteristics, namely, the parameters of the best cell are short-circuit current density (J{sub SC}) of 4.8 mA/cm{sup 2}, open-circuit voltage (V{sub OC}) of 0.59 V, fill factor (FF) of 0.39, and conversion efficiency (η) of 1.12%. Meanwhile, CZTS films annealed under Se vapor shows high crystallinity and high cell performance: the parameters of the best cell are J{sub SC} = 26.2 mA/cm{sup 2}, V{sub OC} = 0.39, FF = 0.48, and η = 4.94%.

  20. Modification of electron states in CdTe absorber due to a buffer layer in CdTe/CdS solar cells

    By application of the ac admittance spectroscopy method, the defect state energy distributions were determined in CdTe incorporated in thin film solar cell structures concluded on ZnO, ZnSe, and ZnS buffer layers. Together with the Mott-Schottky analysis, the results revealed a strong modification of the defect density of states and the concentration of the uncompensated acceptors as influenced by the choice of the buffer layer. In the solar cells formed on ZnSe and ZnS, the Fermi level and the energy position of the dominant deep trap levels were observed to shift closer to the midgap of CdTe, suggesting the mid-gap states may act as recombination centers and impact the open-circuit voltage and the fill factor of the solar cells. For the deeper states, the broadening parameter was observed to increase, indicating fluctuations of the charge on a microscopic scale. Such changes can be attributed to the grain-boundary strain and the modification of the charge trapped at the grain-boundary interface states in polycrystalline CdTe

  1. Modification of electron states in CdTe absorber due to a buffer layer in CdTe/CdS solar cells

    Fedorenko, Y. G.; Major, J. D.; Pressman, A.; Phillips, L. J.; Durose, K.

    2015-10-01

    By application of the ac admittance spectroscopy method, the defect state energy distributions were determined in CdTe incorporated in thin film solar cell structures concluded on ZnO, ZnSe, and ZnS buffer layers. Together with the Mott-Schottky analysis, the results revealed a strong modification of the defect density of states and the concentration of the uncompensated acceptors as influenced by the choice of the buffer layer. In the solar cells formed on ZnSe and ZnS, the Fermi level and the energy position of the dominant deep trap levels were observed to shift closer to the midgap of CdTe, suggesting the mid-gap states may act as recombination centers and impact the open-circuit voltage and the fill factor of the solar cells. For the deeper states, the broadening parameter was observed to increase, indicating fluctuations of the charge on a microscopic scale. Such changes can be attributed to the grain-boundary strain and the modification of the charge trapped at the grain-boundary interface states in polycrystalline CdTe.

  2. Effects of annealing conditions on crystallization of the CZTS absorber and photovoltaic properties of Cu(Zn,Sn)(S,Se)2 solar cells

    Highlights: • CZTS films annealed under H2S and Se ambient showed a different characterization. • The crystallizing temperature of CZTS films annealed under H2S is higher than Se ambient. • Cell parameters of CZTS solar cells annealed Se ambient is better than H2S ambient. • 4.94% efficiency of CZTSSe solar cells annealed under Se ambient was obtained. - Abstract: Cu(Zn,Sn)S2 (CZTS) nanoparticles were synthesized by hot-injection method. Cu(Zn,Sn)(S,Se)2 (CZTSSe) solar cells were fabricated by printing method using CZTS nanocrystallites on molybdenum/glass substrate. The effects of annealing conditions such as temperature and ambient gas on microstructure and photovoltaic properties were investigated. CZTS films annealed in H2S ambient shows low crystallinity, being peeled off easily, and poor photovoltaic characteristics, namely, the parameters of the best cell are short-circuit current density (JSC) of 4.8 mA/cm2, open-circuit voltage (VOC) of 0.59 V, fill factor (FF) of 0.39, and conversion efficiency (η) of 1.12%. Meanwhile, CZTS films annealed under Se vapor shows high crystallinity and high cell performance: the parameters of the best cell are JSC = 26.2 mA/cm2, VOC = 0.39, FF = 0.48, and η = 4.94%

  3. National program plan for absorber surfaces R and D

    Call, P. J.

    1979-01-01

    The optical properties - solar absorptance (..cap alpha../sub s/) and thermal emittance (epsilon/sub t/) - of the receiver surface are important in a wide range of solar energy conversion devices from passive solar buildings to sophisticated two axis tracking concentrators. This report describes a National Plan for Absorber Surfaces R and D and includes the background information (available absorber materials and characteristics, applications, and probable benefits) used to derive the plan.

  4. Development and study on vacuum absorber tubes

    Wang, Jun; Zhang, Yaoming [Southeast Univ., Hohai Univ., Nanjing (China); Liu, Deyou; An, cuicui [Hohai Univ., Nanjing (China)

    2008-07-01

    A new type solar vacuum absorber tube has been developed, and the tensile tests have shown the high reliability of the joint between the metal and glass of the vacuum absorber tube; the fatigue tests have indicated that the bellows of the vacuum absorber tube as well as the interface between the metal and glass can last for as long as 20 years; the weathering tests of the sample, have lasted for an entire year, which proves that the tube design is scientifically and reasonably devised. (orig.)

  5. The ALICE absorbers

    Maximilien Brice

    2006-01-01

    Weighing more than 400 tonnes, the ALICE absorbers and the surrounding support structures have been installed and aligned with a precision of 1-2 mm, hardly an easy task but a very important one. The ALICE absorbers are made of three parts: the front absorber, a 35-tonne cone-shaped structure, and two small-angle absorbers, long straight cylinder sections weighing 18 and 40 tonnes. The three pieces lined up have a total length of about 17 m.

  6. An exposition of the role of external base absorbent of solar energy with intelligent constructional structures with a view to reduction in energy use

    Samira Sadeghi Kelishadi

    2014-07-01

    Full Text Available There is no doubt that one of the most important challenges facing engineers and designers ofarchitectural design and engineering is indeed the problem of energy. It is inline with this trend of thought that energy can be seen as a critical elementwith a view to the enhancement of mans economical and social welfare and it isin the sphere of construction engineering that the need arises for the use ofthe appropriate construction material which can best serve this vital aim ofenergy conservation by using renewable energy sources such as solar energy. Itis therefore a foregone conclusion that the more we are capable of using solarenergy we are helping to conserve our other energy sources and thus help toreduce our overall energy consumption. It is with this view in mind thatconstruction engineers and those working in building design have aimed at usingsystems that can manage energy consumption within their constructionalstructures, having arrived at a point where their building designs can actuallybe termed intelligent or smart constructionalstructures, whereby the system asa whole is capable of using solar energy instead of the traditional fossilfuels. Yet that which makes possible the use of solar energy more so today thanever before is the use of external ducts, which are installed in places mostexposed to sunlight, and have the capability of changing color and becominglighter or darker as the state of exposure calls for is the use of a certaintype of smart glass within the built structure, that makes possible the mostefficient use of sunlight entering the building, having the capability ofchanging color in correlation to the amount of sunlight received and becominglighter or darker appropriately, allowing that quantity of sunlight to enter thebuilding as is needed to counteract the greenhouse effect which causes anuncontrolled increase of temperature within the built structure, and thusallowing the most efficient use of solar energy in keeping

  7. EMITANCE MEASUREMENTS OF SOLAR ABSORBING COATINGS AT 80℃ USING INFRARED SPECTROPHOTOMETER%红外分光光度计测量太阳吸收涂层80℃的发射比

    周旭; 苗建朋; 李静静; 陈革; 章其初

    2012-01-01

    采用红外分光光度计和专门设计的试片恒温器测量80℃时太阳选择性吸收涂层及金属涂层的反射光谱,采用黑体辐射普朗克函数积分计算得到该温度下试样的发射比.试样采用磁控溅射法在平面玻璃载片上制备.实际测量结果表明,该方法测量精度高,测量过程简便快捷.另外,红外分光光度计为通用仪器,反射光谱标样容易制备和计量校准.%The reflectance spectra of solar absorbing coating samples at 80℃ were measured using a infrared spec-trophotometer and thermostat attachment of sample. The nearly normal emittance values of samples at the temperature were calculated by reflectance spectra and the blackbody radiation Planck function. The samples of solar selective coatings were prepared by magnetron sputtering on glass slides. The actual measurement results showed that this method exhibits high accuracy, easy and quick measurement. In addition, infrared spectrophotometer is a standard instrument, and the standard reflectance spectrum values of high reflectance metal sample can be easily obtained through the legal units.

  8. Surface Morphological Studies of Solar Absorber Layer Cu2ZnSnS4 (CZTS Thin Films by Non-vacuum Deposition Methods

    Chandra Sekhar Kanuru

    2014-06-01

    Full Text Available The consumption of fossil fuel globally has been enormous and has reached an alarming rate resulting in fast depletion of the available resources and at the same time polluting the environment. Hence there is a growing need to take cognizance of abundant amount of inexpensive energy available in the nature especially solar energy. Development and commercialization of Photovoltaics has been in focus due to its low cost, high absorption coefficient and suitable direct band gap for solar energy conversion applications. An attempt has been made in this work to synthesize the CZTS thin films by Electro deposition and Sol-gel method on Indium Tin Oxide (ITO glass and Soda Lime Glass( SLG substrates respectively. CZTS thin films have been prepared using a 3-stage electro chemical system wherein the precursors are deposited using platinum foil as a counter electrode and AgCl electrode as a reference electrode and Sol gel method. Surface morphology and optical properties have been studied using Atomic Force Microscopy, Scanning Electron Microscopy, X-ray Diffractometer and UV-Vis Spectroscopy

  9. Heat Transfer Enhancement in a Solar Air Heater with Roughened Duct Having Arc-Shaped Elements as Roughness Element on the Absorber Plate

    Singh, Anil Prakash; Goel, Varun; Vashishtha, Siddhartha; Kumar, Amit

    2016-07-01

    An experimental study has been carried out for the heat transfer and friction characteristics for arc shaped roughness element used in solar air heaters. Duct has an aspect ratio (W/H) of 11, relative roughness pitch (p/e) range of 4-16, relative roughness height (e/D) range of 0.027-0.045, Reynolds number ( Re) range of 2200-22,000 and arc angle (α) was kept constant at 60°. The effects of Re, relative roughness pitch (p/e) and relative roughness height (e/D) on heat transfer and friction factor have been discussed. The results obtained for Nusselt number and friction factor has been compared with smooth solar air heater to see the enhancement in heat transfer and friction factor and it is found out that considerable enhancement takes place in case of heat transfer as well as in friction factor. Correlations were also developed for Nusselt number and friction factor. Thermo-hydraulic performance parameter is also calculated for the same.

  10. PERFORMANCE EVALUATION OF SOLAR COLLECTORS USING A SOLAR SIMULATOR

    M. Norhafana

    2015-11-01

    Full Text Available Solar water heating systems is one of the applications of solar energy. One of the components of a solar water heating system is a solar collector that consists of an absorber. The performance of the solar water heating system depends on the absorber in the solar collector. In countries with unsuitable weather conditions, the indoor testing of solar collectors with the use of a solar simulator is preferred. Thus, this study is conducted to use a multilayered absorber in the solar collector of a solar water heating system as well as to evaluate the performance of the solar collector in terms of useful heat of the multilayered absorber using the multidirectional ability of a solar simulator at several values of solar radiation. It is operated at three variables of solar radiation of 400 W/m2, 550 W/m2 and 700 W/m2 and using three different positions of angles at 0º, 45º and 90º. The results show that the multilayer absorber in the solar collector is only able to best adapt at 45° of solar simulator with different values of radiation intensity. At this angle the maximum values of useful heat and temperature difference are achieved. KEYWORDS: solar water heating system; solar collector; multilayered absorber; solar simulator; solar radiation