Dye molecule/viologen system for a novel photoelectrochromism

Ruthenium (II) tri-(bipyridyl) dye molecules (Ru(II)(bipy)/spl middot/2Cl/sub 2/) were used as a sensitiser which absorbs the visible light in the region of 360-500 nm. The photoexcited sensitiser can transfer charge carriers to an electron acceptor (benzyl-viologen) and lead to redox reactions. Along with these redox reactions the solution changes its color, while LiI or triethylamine (TEA) are added in the solution as electron delays. The coloring and bleaching processes of a test cell filled with the solution were examined exposing to different light intensities.