Correlation between light absorption and electric charge in solid state electrochromic windows

Abstract

Electrochromic windows based on different combinations of the electro chromic materials polyaniline (PANI), Prussian Blue (PB) and tungsten oxide (WO3), with the solid state polymer electrolyte poly(2 acrylam ido 2 methyl propane sulphonic acid) (PAMPS) as an ionic conductor, h as been studied. These windows show a large transmission regulation both in the visible and in the near infrared wavelength region. Integ rated over the solar spectrum, windows with PB deposited on top of PA NI, with WO3 as a complementary coating, are typically able to regula te as much as 50% of the total solar radiation. The relationship bet ween light absorption and charge extraction in electrochromic windows has been studied. The windows are coloured by applying a potential, which is then switched off, and the discharge process is followed by continuously measuring the light absorption and the charge extraction through a connected resistor. From the resulting linear relationship between the absorption and charge extraction, the overall absorption coefficient may be calculated.