Electrochemical Optical-Modulation Device with Reversible Transformation Between Transparent, Mirror, and Black

A novel electrochromic device with three optical states, transparent, specular mirror, and black, is demonstrated. The cell is constructed by sandwiching gel electrolyte containing silver nitrate between one flat and one particle‐modified indium thin oxide electrode. The optical states can be switched by altering the potential across the two electrodes. All changes are reversible and show good stability over 2500 cycles of testing.