Photoelectrochromic heterosupramolecular assemblies

Heterosupramolecular assemblies based on modified transparent nanostructure d TiO2 (anatase) membranes are described. Exposure of these heterosupramole cular assemblies to visible light causes them to turn blue. Furthermore, if a negative potential is applied to the nanostructured TiO2 membrane this b lue color persists for hours. Because only those areas which have been irra diated are blue, and because the lifetime of the blue colored state depends on the potential applied to the nanostructured TiO2 membrane, applications are foreseen for these photoelectrochromic materials.