Showing papers by "Claes-Göran Granqvist published in 1987"
TL;DR: In this paper, the SiO 2 -coated VO 2 films were produced by reactive e-beam evaporation followed by annealing post-treatment, and electrical measurements demonstrated a semiconductor-metal transition at τ c ∼ 60°C.
243 citations
TL;DR: Practical tests demonstrated that a low-emittance coating can prevent frost formation and maintain transparency of a window exposed to the clear sky.
Abstract: Radiative cooling power was computed as a function of the emittance c, of an exposed surface, air temperature, humidity, etc. from the LOWTRAN 5 code. Meteorological data were then used to make semiquantitative estimates on how often frost will form on a surface with given epsilon(s). Practical tests, using SnO(2)-covered glass with epsilon(s) approximately 0.2, demonstrated that a low-emittance coating can prevent frost formation and maintain transparency of a window exposed to the clear sky.
45 citations
23 Feb 1987
TL;DR: In this article, the near-infrared solar transmittance was reduced when Tc was exceeded while the luminous transmittances remained relatively unchanged, and the SiO2-coated VO2 films were used for regulating the energy throughput of windows.
Abstract: VO2 films were produced by reactive e-beam evaporation followed by annealing post-treatment. Electrical measurements demonstrated a semiconductor-metal transition at Tc ~ 60°C. Spectrophotometry showed that the near-infrared solar transmittance was reduced when Tc was exceeded while the luminous transmittance remained relatively unchanged. This thermochromism may be utilized for regulating the energy throughput of windows. Practical application hinges on improved transmittance and on Tc-depression. These goals can be accomplished to some extent by dielectric overlayers, as verified by measurements on SiO2-coated VO2 films.
38 citations
TL;DR: Electrochromic coloration was found to be associated with the formation of a broad absorption band centered at lambda approximately 0.8 microm, and the integrated luminous and solar transmittance could be varied between approximately 75 and 10% and between Approximately 75 and 20%, respectively.
Abstract: Electrochromic NiOxHy coatings were produced by rf magnetron sputtering of Ni in the presence of H2 and O2 followed by treatment of the films in KOH. Spectral transmittance and reflectance were measured in the 0.35 ≤ λ ≤ 2.5-μm wavelength range. The integrated luminous and solar transmittance could be varied between ≈75 and 10% and between ≈75 and 20%, respectively. Electrochromic coloration was found to be associated with the formation of a broad absorption band centered at λ ≈ 0.8 μm.
35 citations
TL;DR: In this article, an electrochromic hydrated nickel oxide films were produced by reactive rf-magnetron sputtering followed by electrochemical treatment in KOH and Spectrophotometry was used to study the modulation of luminous and solar transmittance and assess the durability.
30 citations
17 citations
17 citations
TL;DR: In this article, the authors investigate the radiative heat transfer between blackbody-like surfaces confining an infrared-absorbing gas layer, and find that the gas is able to diminish the heat flux across a 1 cm thick slab by a factor of ∼ 0.7 in comparison with the case of a nonabsorbing medium.
14 citations
TL;DR: Thermochromism in fiber composites is studied with a view to their possible use for controlling the transmission of luminous and solar radiation and scattering off cylindrical objects in the Rayleigh- Gans limit.
Abstract: We study thermochromism in fiber composites with a view to their possible use for controlling the transmission of luminous and solar radiation. Spectrophotometric measurements of collimated and total transmittance were carried out for quartz fibers in carbon tetrachloride. The collimated transmittance showed a peak structure consistent with index matching. The total transmittance was almost featureless; the integrated luminous and solar transmittance decreased by ~20% as the temperature went from 0 to 35 degrees C if the fiber fraction was ?5 vol %. The optical properties could be reconciled with a four-flux model with parameters obtainable from the Mie theory. Specifically, we treated scattering off cylindrical objects in the Rayleigh- Gans limit.
11 citations
5 citations