PbS solar control coatings: safety, cost and optimisation
TL;DR: In this paper, the safety and cost and the optimisation of chemically deposited PbS thin films for solar control applications are presented. But the results of the analysis are limited to the case of 3 mm thick clear glass with a shading coefficient of approximately 50%.
Abstract: Assessments of safety and cost and the optimisation of chemically deposited PbS thin films for solar control applications are presented. The maximum integrated infrared reflectance, 44%, is obtained at a PbS thin film thickness of approximately=95 nm. The corresponding value of the solar control parameters (AM2 case) are: integrated infrared transmittance, 45%; integrated visible transmittance, 17% (yellowish appearance); integrated visible reflectance, 21% (purple appearance); and integrated solar absorptance, 36%. The total solar radiation and heat transfer into the building through a glazing with such a PbS coating is less than 44%, as compared with the approximately=84% of 3 mm thick clear glass, giving a shading coefficient of approximately=50%. A film thickness of 95 nm is obtainable with a deposition time of 50 min from a bath (at 24 degrees C) containing Pb2+ ions and thiourea in the 1:3 molar ratio. However, molar ratios up to 1:5 may be employed, thereby enabling the reduction of deposition time to 35 min. Analyses of the safety and the cost of these coatings have shown excellent promise for their application as medium-efficiency low-cost solar control coatings appropriate for small-scale industrial and 'do-it-yourself' production of the coatings.
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TL;DR: In this article, the authors have described in detail, chemical bath deposition method of metal chalcogenide thin films, it is capable of yielding good quality thin films and their preparative parameters, structural, optical, electrical properties etc.
Abstract: Metal chalcogenide thin films preparation by chemical methods are currently attracting considerable attention as it is relatively inexpensive, simple and convenient for large area deposition. A variety of substrates such as insulators, semiconductors or metals can be used since these are low temperature processes which avoid oxidation and corrosion of substrate. These are slow processes which facilitates better orientation of crystallites with improved grain structure. Depending upon deposition conditions, film growth can take place by ion-by-ion condensation of the materials on the substrates or by adsorption of colloidal particles from the solution on the substrate. Using these methods, thin films of group II–VI, V–VI, III–VI etc. have been deposited. Solar selective coatings, solar control, photoconductors, solid state and photoelectrochemical solar cells, optical imaging, hologram recording, optical mass memories etc. are some of the applications of metal chalcogenide films. In the present review article, we have described in detail, chemical bath deposition method of metal chalcogenide thin films, it is capable of yielding good quality thin films. Their preparative parameters, structural, optical, electrical properties etc. are described. Theoretical background necessary for the chemical deposition of thin films is also discussed.
733 citations
TL;DR: In this article, the basic concepts underlying the chemical bath deposition technique and recipes developed in our laboratory during the past ten years for the deposition of good-quality thin films of CdS, CdSe, ZnS, PbSe, SnS, Bi2S3, BiSe3, SbS3 Sb2S2, CuS, CuSe, etc.
Abstract: In this paper we present the basic concepts underlying the chemical bath deposition technique and the recipes developed in our laboratory during the past ten years for the deposition of good-quality thin films of CdS, CdSe, ZnS, ZnSe, PbS, SnS, Bi2S3, Bi2Se3, Sb2S3, CuS, CuSe, etc. Typical growth curves, and optical and electrical properties of these films are presented. The effect of annealing the films in air on their structure and composition and on the electrical properties is notable: CdS and ZnS films become conductive through a partial conversion to oxide phase; CdSe becomes photosensitive, SnS converts to SnO2, etc. The use of precipitates formed during deposition for screen printing and sintering, in polymer composites and as a source for vapor-phase deposition is presented. Some examples of the application of the films in solar energy related work are presented.
345 citations
TL;DR: In this article, a chemical deposition technique, much simpler and more versatile than previously reported and capable of yielding good quality SnS films of thickness up to approximately 1.2 mu m under a choice of deposition conditions, is presented.
Abstract: A chemical deposition technique, much simpler and more versatile than previously reported and capable of yielding good quality SnS films of thickness up to approximately=1.2 mu m under a choice of deposition conditions, is presented. The as-prepared films are polycrystalline with p-type dark conductivity in the range 10-5-10-4 Omega -1 cm-1 for the thicker ( approximately 1 mu m) films and showing a photocurrent to dark current ratio of 5-10 under 500 W m-2 tungsten halogen illumination. The optical transmittance and reflectance spectra and the photocurrent response curves of a series of SnS samples are explicitly presented to provide insight into possible applications of these films.
181 citations
TL;DR: A survey of binary and ternary metal chalcogenide thin films is given in this paper with respect to their preparative parameters, structural, optical and electrical properties, and the theoretical background of chemical deposition is described in detail.
Abstract: Metal chalcogenide thin film preparation by chemical deposition is currently attracting considerable attention as it is relatively inexpensive, simple and convenient for large area deposition. A variety of substrates such as insulators, semiconductors or metals can be used since it is a low temperature process which avoids oxidation or corrosion of metallic substrates. It is a slow process which facilitates better orientation of crystallites with improved grain structure. Depending upon the deposition conditions, film growth can take place by ion-by-ion condensation of the materials on the substrates or by adsorption of the colloidal particles from the solution onto a substrate. Using this method thin films of groups II–VI, IV–VI, V–VI, I–III–VI etc. have been deposited. In this review article, the theoretical background of chemical deposition is described in detail. A survey of binary and ternary metal chalcogenide thin films is given with respect to their preparative parameters, structural, optical and electrical properties. Such films have been used in solar selective coatings, solar control photoconductors, solid state and photoelectrochemical solar cells.
172 citations
TL;DR: In this article, the structural, optical and photoelectrical properties of thin PbS films were studied and the main characteristic of films as thick as 0.12-0.54 μ m is the photosensitivity, which is influenced by many factors such as film thickness, grain and crystallite size, faults probability, number of layers, thermal treatment and presence of impurities.
Abstract: Thin PbS films were chemically deposited on glass from alkaline baths containing lead nitrate, thiourea and different additions, such as hydroxylamine hydrochloride, triethanolamine or H 2 O 2 . The structural, optical and photoelectrical properties of these films were studied. The main characteristic of films as thick as 0.12–0.54 μ m is the photosensitivity. This parameter is influenced by many factors such as film thickness, grain and crystallite size, faults probability, number of layers, thermal treatment and the presence of impurities. Optical properties of these films were studied comparatively with those of some Au and Ni layers. The VIS. transmission and NIR reflection are comparable with those of the metallic films. The PbS films as thick as 21–62 nm can be applied for solar control coatings.
120 citations
References
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01 Jan 1981
TL;DR: In this article, the preparation, properties, and role of transparent conducting coatings as solar spectrally selective surfaces are discussed, and the use of transparent conductors in photovoltaic conversion is explored.
Abstract: The preparation, properties, and the role of transparent conducting coatings as solar spectrally selective surfaces are discussed. The application of spectrally selective surfaces to photothermal conversion is covered, and the use of transparent conductors in photovoltaic conversion is explored. Measurement techniques used for determining absorptance, emittance, and reflectance are described. The black solar selective surfaces are covered. Much of the presentation is given in a comparative format. 384 references. (LEW)
187 citations
TL;DR: In this article, a range of combination of rsquare operator approximately 30 Omega to 1 M Omega and T% (500 nm) approximately 1 to 65 and a color of reflected daylight (golden yellow, purple, blue, green, etc.) can be obtained from chemical baths constituted from copper(II) chloride, triethanolamine and thiourea at appropriate pH.
Abstract: CuxS thin films with a wide range of sheet resistances (rSquare Operator ) and optical transmittance (T%), indicating different composition x, have been obtained from chemical baths constituted from copper(II) chloride, triethanolamine and thiourea at appropriate pH (10-12). Depending on the deposition parameters, a range of combination of rSquare Operator approximately=30 Omega to 1 M Omega and T% (500 nm) approximately=1 to 65 and a range of colour of reflected daylight (golden yellow, purple, blue, green, etc.) can be obtained. The films have been found to be stable with respect to electrical and optical properties on storage under ambient. Various possible large area applications such as in architectural glazing, photothermal and photovoltaic conversions are discussed.
168 citations
TL;DR: In this paper, the basic requirements of solar control coatings are presented and a comparison of the characteristics of PbS and CuxS coatings against commercially available coatings is provided.
Abstract: Solar control coatings, required for architectural glazing applications in warm climates, must provide controlled optical transmission ( approximately 10-50%) of the solar radiation in the visible region and should reflect efficiently in the infrared (>0.7 mu m) region to create a cool interior in the buildings. Thin films of PbS and CuxS on glass substrates, deposited from chemical baths, are shown to possess excellent solar control characteristics-superior or comparable to the metallic solar control coatings. For example, for an acceptable range of integrated optical transmittance ( approximately 10-20%) in the visible region, the integrated infrared reflectance for AM2 solar spectrum for the different glazings are: PbS coated glass, 50%; CuxS coated glass, 14%; stainless steel/Cu coated glass, 25% and tinted glass, 4%. The CuxS and PbS coatings also have the advantage of giving pleasant reflected colours (golden, purple, blue, etc), which improves the cosmetic appearance. This paper presents the basic requirements of solar control coatings and provides a comparison of the characteristics of PbS and CuxS coatings against commercially available coatings.
138 citations
01 Jan 1982
111 citations
TL;DR: In this article, the photo-to-dark conductivity ratio up to 109 and photoconductivity up to 3 Omega -1 cm-1 for white illumination approximately 300 W m-2 can be prepared from chemical baths containing thiourea and triethanolamine complex of cadmium ions.
Abstract: Cadmium sulphide thin films showing photo-to-dark conductivity ratio up to 109 and photoconductivity up to 3 Omega -1 cm-1 for white illumination approximately 300 W m-2 can be prepared from chemical baths containing thiourea and triethanolamine complex of cadmium ions. The photocurrent decay time depends on the bath temperature and the duration of storage and it ranges from a few seconds to 104 s per decade. The optical transmission of the films also varies significantly: from about 10% to 70-80% (above the band-gap absorption), depending on the deposition conditions. The high activation energy approximately=1 eV for dark conductivity as well as the high photosensitivity suggest the nearly stoichiometric nature of the films. The implications of these characteristics in various opto-electronic applications are discussed.
93 citations