Electrochemical and spectroscopic studies of electrochromic materials

摘要

The demand for energy savings in buildings will increase in the coming years, as the world's attention is drawn towards environmental aspects and energy economizing. Windows, which are able to dynamically control the sun radiation throughput, will play an important role in this respect. Electrochromic windows, popularly called smart windows, offer an elegant solution. These smart windows change color with an applied voltage, and may be controlled automatically by the use of a temperature sensor inside the building and a light sensor outside. The sun radiation is mainly confined to the 300-3000 nm wavelength region, with ultraviolet (UV) light below 400 nm, visible (VIS) light between 400-700 nm and near infrared (NIR) radiation between 700-3000 nm. The importance of light modulation in the NIR region should be stressed, since this region contains about half of the solar energy. Beside the solar energy modulation, we have to take into account that we often want to look through a clear, transparent window with no color shades. An electrochromic window may be composed by an electrochromic coating (EC), an ionic conductor (IC) and a counter electrode (CE) between two glass plates, each with a transparent conductor (TC). Such a window configuration is called a five-layer device, which is the type treated here. My results include the extension of the transmission spectra into the near infrared region for windows based on polyaniline and tungsten oxide glued together with a solid polymer electrolyte, thus covering the whole solar spectrum. Furthermore, a novel electrochromic window device is fabricated, by incorporating prussian blue into the window together with polyaniline and tungsten oxide, enhancing the solar modulation even further. 176 refs., 96 figs., 5 tabs. (ERA citation 19:024899)