Semiconductor Electrodes XXV . The System. Photoelectrochemical Cells and Photoelectrochromic Displays

摘要: The photoreduction of aqueous solutions 1,1'‐diheptyl‐4,4'‐bipyridyl (heptyl viologen, HV2+) bromide on was investigated. Under irradiation with light wavelengths below 885 nm, the HV2+ to form a precipitate violet occurs at potential ~400 mV more positive than reversible couple Pt. Oxidation back soluble in dark negative potentials. Photoelectrochemical low capacity storage cells based this reaction Cu, Ni, or counterelectrodes were constructed. In such cells, under illumination, electrode behaves as cathode, photovoltage develops, and current flows external circuit, while precipitates surface, counterelectrode is oxidized. dark, opposite direction, anode, reduction counterelectrode. Such cell also produces an alternating electrical output periodic illumination. Photoelectrochromic utilizing simultaneous addressing signals are proposed.