<p>The optical properties of electrochromic materials can be changed by application of an electrical voltage. The conventional electrochromic device consists of several thin films of electrochromic materials and layers for electron- and ion conduction. The ion conductor in devices intended for applications using visible light is often a polymer electrolyte that is used to laminate two half-cells together. The miniaturization of satellites has led to reduced mass and volume available for systems to handle temperature variations onboard. The satellite will be submitted to large variations in the radiating environment in an earth bound orbit. An electrochromic device could provide adaptable radiation exchange due to its variable infrared optical properties. The polymer electrolyte is not a desirable component in the space environment, but it can be replaced by an inorganic thin film so that an all-thin-film (ATF) device is obtained. </p><p>This thesis investigates the optical properties of amorphous and crystalline WO<sub>3</sub>, as well as the performance of ATF devices with sputtered ZrO<sub>2</sub> as the ion conductor. The infrared reflectance for Li-intercalated WO<sub>3</sub> has been measured in the wavelength range 2-50 mm. The near infrared absorption for low intercalation levels showed good agreement with large polaron theory. The infrared reflectance increased with higher intercalation levels and exhibited a free-electron behaviour. The infrared reflectance of a laminated device with polymer electrolyte was measured, and the calculated emittance varied between 0.56 and 0.65. The ATF device consisted of thin films of WO<sub>3</sub>, ZrO<sub>2</sub> and NiV<sub>x</sub>O<sub>y</sub>H<sub>z</sub>, as well as evaporated Al top contacts. The substrates were commercial ITO on glass. The emittance for different device designs was calculated from reflectance measurements, and could be varied between 0.33 and 0.59. This makes them strong contenders to other contemporary emittance modulating devices.</p>
| Identifer | oai:union.ndltd.org:UPSALLA/oai:DiVA.org:uu-3917 |
| Date | January 2004 |
| Creators | Larsson, Anna-Lena |
| Publisher | Uppsala University, Department of Engineering Sciences, Uppsala : Acta Universitatis Upsaliensis |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Doctoral thesis, comprehensive summary, text |
| Relation | Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, 1104-232X ; 923 |
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