Switching colors with electricity

In response to a small electrical voltage (typically around 1 volt), electrochromic materials will change, evoke or bleach their color. The electricity induces in the material a process of either reduction (gain of electrons) or oxidation (loss of electrons). A chemical has a characteristic range of energies over which it will interact with wavelengths in the electromagnetic spectrum, but these reduction or oxidation processes (collectively called redox reactions) alter the energy bands the chemical will absorb. In electrochromic materials, the change corresponds to the visible region of the electromagnetic spectrum.