Electrolyte solutions for electrochromic devices such as rear view mirrors
and displays with low leakage currents are prepared using inexpensive,
low conductivity conductors. Preferred electrolytes include bifunctional
redox dyes and molten salt solvents with enhanced stability toward
ultraviolet radiation. The solvents include lithium or quaternary
ammonium cations, and perfluorinated sulfonylimide anions selected from
trifluoromethylsulfonate (CF.sub.3SO.sub.3.sup.-),
bis(trifluoromethylsulfonyl)imide ((CF.sub.3SO.sub.2).sub.2N.sup.-),
bis(perfluoroethylsulfonyl)imide
((CF.sub.3CF.sub.2SO.sub.2).sub.2N.sup.-) and
tris(trifluoromethylsulfonyl)methide ((CF.sub.3SO.sub.2).sub.3C.sup.-).
Electroluminescent, electrochromic and photoelectrochromic devices with
nanostructured electrodes include ionic liquids with bifunctional redox
dyes.