Reversible electrochemical mirror (REM) smart window

A novel smart window device based on reversible electrodeposition of silver is described. This device typically comprises a gamma-butyrolactone electrolyte sandwiched between a mirror electrode and a metallic grid counter electrode (on glass substrates). The mirror electrode is indium tin oxide (ITO) with a thin overlayer of sputtered platinum (15Angstrom), which acts as a nucleation layer so that highly-reflective electrodeposits are obtained. Light reflectance is increased by deposition of silver metal on the mirror electrode, and device transmission is increased by deposition of silver on the grid counter electrode. Since the same reversible reaction occurs at both electrodes, the power required for switching is low and no voltage is needed to maintain a given mirror state. This reflective device is more efficient for preventing interior solar heating than electrochromic devices based on light absorption.