The Goal

It is desirable to combine solar photovoltaic and solar thermal applications in order to extract the maximum benefit from the sun's energy, creating both electricity and useful heat. To maximize output, high solar absorbtance, and low thermal emissivity are required.

A non selective coating (like black paint) has a high thermal emittance (gives off thermal radiation (heat) to the environment) and a high absorbtance of solar radiation.

Selective coatings can allow us to manipulate the ratio of absorbtance to emittance. Some selective coatings are strong absorbers of solar radiation, but are transparent to thermal radiation, in that case, thermal emittance is determined by the properties of what the coating is applied to.

Things To Keep In Mind

Emittance: Ability of a surface to emit heat by radiation. Emissivity is the ratio of emission of a surface to that of a black body at the same temperature. The duller the material, the higher the emissivity, the more reflective the material, the lower the emissivity. Think of comparing a bright white surface and a dull black surface in the middle of summer. The black surface, is much hotter to touch. Emissivity is a surface property, so surface roughness, temperature and wavelength all have an influence on it.

Reflectance: The percentage of incoming energy reflected off a surface at a given wavelength.

Absorbtance: The fraction of light absorbed by a sample at a given wavelength.

Transmittance: The fraction of light at a given wavelength that passes through a sample.

Fundamentals of Semiconductors/PV

The following equations came from Solar Cells by Martin E. Green

pg 41 Reflection

Where:

  • is the real part of the index of refraction
  • is the imaginary part of the index of refraction
  • Index of Refraction

Note: Transmission is T = 1 - R


Absorption of Light

Absorbed light at a distance into the semiconductor

Intensity of light = I

Note:

Math Equation Help in Wiki

http://en.wikipedia.org/wiki/Help:Displaying_a_formula

Other Wiki Basics

http://www.appropedia.org/Help:Contents

Direct Band Gap Semiconductor

Where

  • Final energy state
  • Initial energy state
  • Band Gap Energy
  • A is a constant with a value of 2E4 when alpha is expressed in and hf and is in eV.

Indirect Band Gap Semiconductor


Where

  • is energy of an absorbed phonon with the required momentum

The values can be found in Table 3.1 page 49 for Silicon

Relationship between wavenumber, wavelength, & energy

File:Ev Wavenumber Wavelength.xls

Testing Papers

The following papers are to help create a procedure for measuring emmisivity ect.

This article talks about the different colour paints and their ability to absorb the spectrum of light. Temperature was also observed and found the black gets the hot while lighter colours remain cooler. It has some interesting graphes to show this. 5mjmp 20:16, 22 September 2009 (UTC)


T. Mouhib, A. Mouhsen, E.M. Oualim, M. Harmouchi, J.P. Vigneron, P. Defrance. Optical Materials 31 (2009) 673–677

The authors are studying spectrally selective surfaces in a radiative cooling application. They assume that heat transfer occurs only by radiation and ignore the effects of conduction and convection. They state that at equilibrium the energy emitted is balanced by the energy that is absorbed.Absorptance is defined as 1-(Rsol+Tsol), where are Rsol is the solar reflectance (estimated as the average spectral reflectance over the entire solar spectrum). Measured reflectance, transmittance and absorptance using a spectroradiometer and a monochromator. Have graphs of Reflectance vs wavelength


H. J. Brown-Shaklee, W. Carty and D. D. Edwards. Solar Energy Materials & Solar Cells 93(2009)1404–1410


  • Structure and optical properties of pulsed sputter deposited CrxOy/Cr/Cr2O3 solar selective coatings H. C. Barshilia, N. Selvakumar and K.S. Rajam. Journal of Applied Physics 103, 023507 (2008)
    • Black chrome coatings used for domestic hot water applications. This study designed a dielectric/metalic/dielectric coating of Cr2O3 resulting in high absorptance in the visible region and low emittance in the IR region. 3 layers deposited on copper substrate by chemical vapour deposition.
    • Notes that info on thermal stability, microstructure and optical properties are lacking
    • Used XRD, x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), micro-Raman spectroscopy, solar spectrum relectometer and emissometer and a phase modulated spectroscopic ellispometry

MODELS FOR THE ANGLE-DEPENDENT OPTICAL PROPERTIES OF COATED GLAZING MATERIALS

M. Rubin, R. Powles and K. Von Rottkay. MODELS FOR THE ANGLE-DEPENDENT OPTICAL PROPERTIES OF COATED GLAZING MATERIALS. Solar Energy Vol. 66, No. 4, pp. 267–276, 1999


Their goal was to find if the optical constants of their materials were close to the ideal ones, and learn enough about the materials to improve them if they weren't. Commecial absorber in question had a solar absorptance of 0.94-0.96, and a thermal emittance of 0.13-0.15. Tools employed:

  • Rutherford backscattering to determine atomic composition
  • Xray photo electron spectroscopy for surface composition
  • Non-standard spectrophotometer with an integrating sphere to measure absolute reflectance and transmittance (in this case sample is loaded on a ring and sphere 4mm large acts as the detector and is rotated all around the sample

Although graphs in paper show different temperatures (0ºC and 55ºC) measurements for reflectance, no mention is made of how they did this in the paper


Although this article is focused on testing samples with a high reflectivity, high infrared emittance in order to reduce residential cooling loads, some of their measurement techniques could be used by us, as they tested similar materials. They suggest two ASTM standards:

  • ASTM Standard Test Method E903-88 Hemispherical spectral reflectance of the samples oer the solar bandwidth from 300 to 2500nm. This one used an integrating sphere
  • ASTM E480-71 Long-wave infrared reflectance of samples allowing calculation of reflectance

They also used an infrared camera to show different heat emission levels


TPV radiator requires that high temperature photons are emitted to TPV cells for converstion to electricity, and it is desirable to enhance emissivity. They've tried to do this with coatings and surface roughness. Characterization equipment used:

  • Scanning electron microscopy
  • X-ray diffraction
  • Assumed no transmittance (e=1-R) and measured spectral reflectance . Assume that optical properties are independent of temperature. Equation given for total hemispherical emittance at a given temperature from the spectral emittance data and the black body distribution function at the temperature of interest

Reflectance, Solar Absorptivity, and Thermal Emissivity of SiO2-Coated Aluminum

http://www.opticsinfobase.org/DirectPDFAccess/E75F6CB1-BDB9-137E-CF0BBAB1124D8A11_15646.pdf?da=1&id=15646&seq=0

G. Hass, J. B. Ramsey, J. B. Heaney, and J. J. Triolo. Reflectance, Solar Absorptivity, and Thermal Emissivity of SiO2-Coated Aluminum. February 1969 / Vol. 8, No. 2 / APPLIED OPTICS

5mjmp 14:53, 23 September 2009 (UTC)


Determination of global absorptivity and emissivity of some opaque bulk materials using an integrating sphere calorimeter without ports

http://www.iop.org/EJ/article/0957-0233/18/8/043/mst7_8_043.pdf?request-id=5a363ede-ec3c-4a8b-b3fa-c4fd75d6f9f8

Reccab M Ochieng, Frederick N Onyango and Albert J Owino. Determination of global absorptivity and emissivity of some opaque bulk materials using an integrating sphere calorimeter without ports. Meas. Sci. Technol. 18 (2007) 2667–2672

5mjmp 14:57, 23 September 2009 (UTC)

Monte Carlo method in optical radiometry

http://www.iop.org/EJ/article/0026-1394/35/4/44/me8444.pdf?request-id=15db0a6c-a299-4c86-ac18-879458afd6af

A. V. Prokhorov. Monte Carlo method in optical radiometry.Metrologia, 1998, 35, 465-471

5mjmp 14:39, 24 September 2009 (UTC)

MEASUREMENT OF THE TEMPERATURE OF A SURFACE IRRADIATED BY CONCENTRATED LIGHT

http://www.springerlink.com/content/j0w9036437418411/fulltext.pdf

V. V. Kan, T. T. Riskiev and T. P. Salikhov. MEASUREMENT OF THE TEMPERATURE OF A SURFACE IRRADIATED BY CONCENTRATED LIGHT. 0022-0841/91/6104-1284512.50 1992 Plenum Publishing Corporation

5mjmp 14:56, 24 September 2009 (UTC)


Applications for the Integrating Sphere in the Near-Infrared Spectral Region

http://www.piketech.com/technical/application-pdfs/Integrating-Sphere-NIR-Spectral-Region.pdf#search="integrating sphere"

Gabor Kemeny. Applications for the Integrating Sphere in the Near-Infrared Spectral Region. PIKE Technologies.

Although we are using a Mid-Infrared Integrating Sphere, this might spark some ideas...

5mjmp 15:17, 24 September 2009 (UTC)

Mid-IR IntegratIR – Integrating Sphere

http://www.piketech.com/products/product-documentation-pdfs/MidIRIntegratIR_PDS.pdf#search="integrating sphere"

Pike Technologies. Mid-IR IntegratIR – Integrating Sphere. ©2008 PIKE Technologies. All rights reserved. All trademarks are the property of PIKE Technologies.

This is Pike Technologies spec sheet for our integrating sphere... Wish there was more... sigh...

5mjmp 15:22, 24 September 2009 (UTC)

Integrating Spheres for Mid- and Near-infrared Reflection Spectroscopy

Introduction:Integrating sphere instrumentation has historically been the primary analysis tool for accurate quantitative characterization of reflectance and absorptance of samples and materials that exhibit a high degree of scattering. The four most widely used types of instruments for performing reflectance measurements of diffusing surfaces are biconical mirror systems, gonio-reflectometers, 2p conic mirror reflectometers, and integrating spheres. Spectrophotometer accessories of biconical design (e.g. “praying mantis” type devices) are the most commonly used for semiquantitatively characterizing the diffuse reflectance of powdered samples. However, because of the restricted angular range of measurement, a fraction of the reflected light that is dependent on the specific directional scattering properties of each sample will be lost. This limits the degree of accuracy for these devices. For quantitative measurements of hemispherical diffuse reflectance, methods based on the 90C years of accumulated knowledge on integrating spheres are preferred. Two comprehensive reviews of absolute methods for integrating sphere-based reflectance measurements were published in the 1970s by Budde1 and the International Commission on Illumination (CIE).2 Since that time, integrating spheres for the mid-infrared have become commonplace, and major advances have occurred in the areas of computational optics modeling of integrating spheres, coupling detectors to spheres with nonimaging concentrators, and the development of new nearly Lambertian reflectors. A single article must necessarily be focused on specific aspects of integrating sphere reflectance spectroscopy. In this article we will describe the integrating sphere instrumentation that is used in diffuse reflection spectroscopy: how sphere systems function, what the various designs and methods for reflectance and transmittance measurement are, both absolute and relative, what the sources of measurement error are, and why sphere systems are used in preference to other techniques. We begin by defining the specialized terms associated with diffuse reflectance measurement in Section 2, followed by a short historical review of the important developments in the use of integrating spheres for reflectance in Section 3. The most important characteristic parameter of an integrating sphere, its throughput (efficiency), is discussed in Section 4. This provides an introduction to a detailed description and comparison of both absolute and relative methods that are used in sphere systems in Section 5. Sources of error and measurement uncertainty are addressed in Section 6. A sampling of current commercial sphere reflectometer systems is described in Section 7, followed by a summary in Section 8.


L. M. Hanssen1 and K. A. Snail. Integrating Spheres for Mid- and Near-infrared Reflection Spectroscopy. Handbook of Vibrational Spectroscopy. (c) John Wiley & Sons Ltd, Chichester, 2002

http://physics.nist.gov/Divisions/Div844/PDFs/HndBkSphere.pdf

5mjmp 13:28, 28 September 2009 (UTC)

Integrating Sphere for Imperfectly Diffuse Samples

Abstract:An integrating sphere for determining spectral reflectance and transmittance as a function of angle of incidence and wavelength in the 0.33- to 2.5-,u region is described. Geometrical arrangement of sample, entrance port, and detector as well as directional characteristics of detector and sphere wall coating permit absolute or relative measurements to be made for a sample with an arbitrary reflection-distribution function.

D. K. EDWARDS, J. T. GIER, K. E. NELSON, and R. D. RODDICK, "Integrating Sphere for Imperfectly Diffuse Samples," J. Opt. Soc. Am. 51, 1279-1288 (1961) http://www.opticsinfobase.org/abstract.cfm?URI=josa-51-11-1279

5mjmp 18:39, 28 September 2009 (UTC)

http://www.opticsinfobase.org/abstract.cfm?id=76133


Comparison of four analytic methods for the calculation of irradiance in integrating spheres

Abstract: The relative merits of four methods—energy balance, summation of reflections, inversion of the irradiancetransfer matrix, and solution of the integral equation—are compared by using each to determine irradiance in a multizone true sphere and in a sphere with a flat port; in the process several new solutions are presented. Although limited in applicability, the energy-balance method is by far the most direct. For the flat-port configuration the relationships among various published expressions are established; furthermore, the curvedsurface interreflection irradiance is shown to be nonuniform when the initial irradiance is restricted to a part of the curved surface.

John F. Clare, "Comparison of four analytic methods for the calculation of irradiance in integrating spheres," J. Opt. Soc. Am. A 15, 3086-3096 (1998) http://www.opticsinfobase.org/abstract.cfm?URI=josaa-15-12-3086

5mjmp 18:39, 28 September 2009 (UTC)

http://www.opticsinfobase.org/abstract.cfm?URI=josaa-15-12-3086

Matrix method for integrating-sphere calculations

Abstract:Aplicable to any sphere configuration, including those with flat areas, specular samples, and baffles, and is especially effective when used in computer simulations of sphere irradiance. The formalism can accommodate the angular sensitivity of any detector or the bidirectional-reflectance distribution function of any sample. Examples of simple analytical solutions are presented, and computer simulation is demonstrated with calculations of the irradiance inhomogeneities caused by underfilling a flat sample. In particular, the simulation shows that, when the input beam does not completely fill a flat sample, the sample is surrounded by a band of reduced irradiance. Outside this dark band, the irradiance is increased slightly. The width of the dark band, but not its depth, increases as the beam size decreases relative to the sample size. The depth depends on sample size and reflectance. Outside the dark-band region, the irradiance shifts due to sample underfilling are much smaller than the easily avoidable, first-order errors caused by neglecting the flat-sample effects.

Herbert L. Tardy, "Matrix method for integrating-sphere calculations," J. Opt. Soc. Am. A 8, 1411-1418 (1991) http://www.opticsinfobase.org/abstract.cfm?URI=josaa-8-9-1411

5mjmp 18:41, 28 September 2009 (UTC)

http://www.opticsinfobase.org/abstract.cfm?URI=josaa-8-9-1411


Evaluation of correction factors for transmittance measurements in single-beam integrating spheres

Abstract:An integrating sphere for transmittance measurements at normal and oblique angles of incidence has been constructed. The sphere is a single-beam instrument that uses a small-area silicon diode as the detector. The entry port is only 0.37% of the total wall area and has an oblong shape to permit measurements at high angles of incidence for scattering samples. A small beam size has been made possible by using a low-noise preamplifier system for the detector circuit. The oblong port shape and a small beam size make it possible to perform simulated double-beam measurements at near-normal incidence. Modified correction factors for the sample reflectance have been derived. Special attention has been paid to the separation into a diffuse and a specular component of the transmitted light. Results have been compared with the results of measurements on a double-beam instrument, and the correction factors for specular and diffuse samples have been experimentally verified. The importance of using the right correction factors for different types of samples has been evaluated together with the influence of the sphere parameters.

K. Grandin and A. Roos, "Evaluation of correction factors for transmittance measurements in single-beam integrating spheres," Appl. Opt. 33, 6098-6104 (1994) http://www.opticsinfobase.org/abstract.cfm?URI=ao-33-25-6098

5mjmp 18:44, 28 September 2009 (UTC)

http://www.opticsinfobase.org/abstract.cfm?URI=ao-33-25-6098


Reflection and transmission measurements with an integrating sphere and Fourier-transform infrared spectrometer

Abstract:A method of measuring the total reflection and transmission spectra of scattering materials with an integrating sphere and a Fourier-transform infrared spectrometer is studied. The reflectance measurement system is considered in a specific case where the incident beam overfills the back side port of the sphere, and the correction functions for measured spectra are derived for this case. Correction formulas are based on the energy balance between incident radiation and absorbed or escaped radiation in the system. The absorption spectrum of the material is calculated from the corrected spectra. The optical properties of paper samples and radiating surfaces of infrared dryers in the 0.4-20-pum wavelength range are determined. The correction formulas are compared with previous work presented in the literature.

Kari T. Ojala, Esa Koski, and Markku J. Lampinen, "Reflection and transmission measurements with an integrating sphere and Fourier-transform infrared spectrometer," Appl. Opt. 31, 4582-4589 (1992) http://www.opticsinfobase.org/abstract.cfm?URI=ao-31-22-4582

5mjmp 18:46, 28 September 2009 (UTC)

http://www.opticsinfobase.org/abstract.cfm?URI=ao-31-22-4582


Stray-light corrections in integrating-sphere measurements on low-scattering samples

Abstract:A method for correcting integrating-sphere signals that considers differences in the angular distribution of scattered light is extended to sources of errors that are due to stray light from imperfect optical components. We show that it is possible to measure low levels of scattering, below 1%, by using a standard integrating sphere, provided that the various contributions to stray light are taken into account properly. For low-scattering samples these corrections are more important than those from the angular distribution of the scattering. A procedure for the experimental determination of stray-light components is suggested. Simple, easy to use, compact equations for the diffuse and specular reflectance and transmittance values of the sample as functions of the recorded signals are presented.

Daniel Rönnow and Arne Roos, "Stray-light corrections in integrating-sphere measurements on low-scattering samples," Appl. Opt. 33, 6092-6097 (1994) http://www.opticsinfobase.org/abstract.cfm?URI=ao-33-25-6092

5mjmp 18:48, 28 September 2009 (UTC)

http://www.opticsinfobase.org/abstract.cfm?URI=ao-33-25-6092

Explicit solution of the spectral radiance in integrating spheres with application to the Earth Radiation Budget Experiment ground calibration

Abstract:An explicit solution of the spectral radiance leaving an arbitrary point on the wall of a spherical cavity with diffuse reflectivity is obtained. The solution is applicable to spheres with an arbitrary number of openings of any size and shape, an arbitrary number of light sources with possibly nondiffuse characteristics, a nonuniform sphere-wall temperature distribution, nonuniform and nondiffuse sphere-wall emissivity, and nonuniform but diffuse spherewall spectral reflectivity. A general measurement equation is obtained that describes the output of a sensor measuring the sphere output within a given field of view and with specified angular and spectral responses measuring the sphere output. The results are applied to the Earth Radiation Budget Experiment (ERBE) integrating sphere. The sphere-wall radiance uniformity, loading effects, and nonuniform wall temperature effects are investigated. It is shown that by using appropriate interpretation and processing, a high-accuracy shortwave calibration of the ERBE sensors can be achieved.

Nesim Halyo and Deborah B. Taylor, "Explicit solution of the spectral radiance in integrating spheres with application to the Earth Radiation Budget Experiment ground calibration," J. Opt. Soc. Am. A 5, 520-534 (1988) http://www.opticsinfobase.org/abstract.cfm?URI=josaa-5-4-520

5mjmp 18:54, 28 September 2009 (UTC)

http://www.opticsinfobase.org/abstract.cfm?URI=josaa-5-4-520

Interpretation of integrating sphere signal output for non-Lambertian samples

Abstract:A new formalism is derived for the analysis of signal output from double-beam integrating spheres. The analysis explicitly considers the effects of port losses and a non-Lambertian sample surface and introduces a separation of the diffusely reflected light into two parts: one which should be analyzed as a specular component and one which is fully diffuse. An experimental procedure to determine the two parameters in the formalism is described for two cases, a brushed copper and a rolled aluminum surface, and it is experimentally verified that the formalism eliminates spurious structure from the barium sulfate reference. A criterion is also given for the selection of barium sulfate or polytetrafluorethylene powder as a reference material.

Arne Roos and Carl G. Ribbing, "Interpretation of integrating sphere signal output for non-Lambertian samples," Appl. Opt. 27, 3833-3837 (1988) http://www.opticsinfobase.org/abstract.cfm?URI=ao-27-18-3833

5mjmp 19:24, 28 September 2009 (UTC)

http://www.opticsinfobase.org/abstract.cfm?URI=ao-27-18-3833

Effects of non-Lambertian surfaces on integrating sphere measurements

Abstract:The effects of non-Lambertian scattering of the interior wall of an integrating sphere are examined through a sphere simulation model. The model employs Monte Carlo techniques. A sphere used for measurement of directional–hemispherical reflectance is modeled. The simulation allows sphere wall scattering to vary from perfectly Lambertian to perfectly specular in steps. The results demonstrate that significant measurement error can result as the scattering deviates from the Lambertian ideal. The error is found to be a strong function of the wall reflectance value as well: it is minimized for reflectances approaching 1.0 and increases as the reflectance value decreases to the minimum value examined of 0.5. The magnitudes of the errors associated with non-Lambertian scattering are also shown to be relatively independent of the specific field of view of the detector used in the measurement.

L. M. Hanssen, "Effects of non-Lambertian surfaces on integrating sphere measurements," Appl. Opt. 35, 3597-3606 (1996) http://www.opticsinfobase.org/abstract.cfm?URI=ao-35-19-3597

5mjmp 19:29, 28 September 2009 (UTC)

http://www.opticsinfobase.org/abstract.cfm?URI=ao-35-19-3597

Helpful Papers

[1] Limits to the Efficiency of Silicon Multilayer Thin Film Solar CellsS.R. Wenham, M.A. Green, S. Edmiston, P. Campbell, L. Koschier, C.B. Honsberg, A.B. Sproul, D. Thorpe, Z. Shi and G. Heiser. Solar Energy Materials and Solar Cells. Volumes 41-42, June 1996, Pages 3-17

This article is a detailed report on silicon multilayer multijunction thin film (MMTF) solar cells. The article talks about the performance of multilayer solar cells, quantum efficiencies, resistive losses, open circuit voltage, tolerance to grain boundaries, junction recombination and limits to efficiency. By injecting carriers between parallel layers the MMTF are ablilty to minise lateral resistance losses. It was found through testing that the efficiency was about 15%.


[2]Solar Collector Overheating Protection M. Slaman and R. Griessen. Solar Energy. Volume 83, Issue 7, Pages 982-987 The article is about reducing the about of light interacting with the PV panel to reduce the amount of heat generated by the PV panel. They use a primatic structure to reduce the incoming light. Several different experiments were complete; the light was shawn directly at the panel with the primatric cover, the panel was tilted to mimic the earth's rotation and two layers of the primatic structure were used. The conclusion was that it did help reduce the amount of light and therefore some of the temperature. Further publications will use the light reducing properties of pyramids and cones.

[3]Solar@anu

This paper just talks about the resarch being completed at the Australian National University. They are studying the effects of impurities on semiconductors such as iron impurities. They mainly work on multicrystalline silicon cells which usually have thin films applied ot thier surfaces. Furthermore, they are looking at ways to get the maximum benift from thin films such as amorphous silicon and silicon nitride.

Sliver cells are highly efficient thin single crystalline solar cells which have reached an effiency greater than 20%.

They are also looking at Fluorescent Organic Dyes which have several interesting properties such as they emit one wavelength but emit a longer one and the emission is random. If this dye were applied to glaze the effiency of the PV would increase since the glaze would reflect less light and therefore more light would make contact with the PV cells.

They have also looked at PVTs and residential scale thermal systems.

Email at: solar@anu.edu.au


[4]TCO and Light Trapping in Silicon Thin Film Solar CellsJoachim Müller, Bernd Rech, Jiri Springer and Milan Vanecek. Solar Energy. Volume 77, Issue 6, December 2004, Pages 917-930


[5]Fabrication and optimisation of highly efficient cermet-based spectrally selective coatings for high operating temperature S. Esposito, A. Antonaia, M.L. Addonizio, and S. Aprea. Thin Solid Films, 517 (2009) 6000–6006


[6]Photoreflectance study of Si delta-doped low-temerature GaAs grown by molecular beam epitaxy. T.M. Cheng and C.Y. Chang. Journal of Applied Physics. Vol. 77, No. 5


[7]Optical constants and film density of TiNxOy solar selective absorbers. M. Lazarov, P.Raths, H. Metzger, and W.Spirkl. Journal of Applied Physics, Vol. 77, No. 5


[8]Performance improvement of organic solar cells with moth eye anti-reflection coating. K. Forberich, G. Dennler, M. Scharber, K. Hingerl, T. Fromherz, and C. Brabec. Thin Solid Films. Vol. 516. No 20. 30, August 2008. P.7167-7170


[9] Mg-Ti-H thin films for smart solar collectors. D.M Borsa, A Baldi, M. Pasturel, H. Schreuders, B. Dam, and R. Griessen. Applied Physics Letters. Vol. 88 June 14, 2006


[10]On the development, optical properties and thermal performance of cool coloured coatings for the urban environment. A Synnefa, M. Santamouris, and K. Apostolakis. Solar Energy. Vol. 81, No. 4. April 2007, Pages 488-497


[11]Nanostructured black cobalt coatings for solar absorbers. Z. Hamid, A. Aal, and P. Schmuki. Surface and Interface Analysis. October 10, 2008


[12]Structure and optical properties of pulsed sputter deposited CrxOy/Cr/Cr2O3 solar selective coatings. H Barshilia, N. Selvakumar, and K. S. Rajam. Journal of Applied Physics. Vol. 103 (2008)


[13]Solar selective absorber coating for high service temperatures, produced by plasma sputtering. M. Lanxner, Z. Elgat. Proc. SPIE Vol. 1272. February 15, 2005


[14]Solar selective coatings based on Nickel Oxide obtained via spray pyrolysis. M. Voinea, E. Ienei, C. Bogatu, A. Duta. Journal of Nanoscience and Nanotechnology. Vol. 9 No. 7, July 2009. Pages 4279-4284


[15]TiAlN/TiAlON/Si3N4 tandem absorber for high temperature solar selective applications. D.V. Sridhara Rao and K. Muraleedharan. Applied Physics Letters. Vol 89. November 8 2006.

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