TiQ(B) obtained from K2Ti409 by hydrolysis and subsequent heating is a semiconductor whose crystal structure allows the insertion of guest atoms. Photoelectrochemical experiments characterized the polycrystalline material as n-type with an energy gap of 3 eV. As a result of electrochemical reduction of protons at TiOz(B)-electrodes new electronic states appear within the energy gap, making the semiconductor sensitive for visible light. These states originate from intercalated hydrogen which diffuses through the sample. Upon optical excitation of these states an anodic photocurrent is observed that can be interpreted as light-induced deintercalation of hydrogen from TiOa(B) to give protons.

The agyrodite Cu~ xPSjI is simultaneously a copper ion conductor and a p-type electronic semiconductor. With an energy gap of AEc = 2.05 eV, the compound intercalates copper upon illumination as demonstrated in photoelectrochemical experiments. The intercalation of copper is accompanied by a color change which is believed to be due to an annihilation of Is-color centers. In experiments in which Cu was partially replaced by Ag, photointercalation was verified by means of x-ray fluorescence measurements. It is shown how such a photointercalation reaction could be used to store optical information.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 169.233.248.124 Downloaded on 2015-04-03 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 169.233.248.124 Downloaded on 2015-04-03 to IP

Experiments are presented that demonstrate the possibility of photon energy conversion with a photoelectrochemical insertion reaction. The reaction is performed with the Cu+-conducting semiconductor copper thiophosphate (Cu3PS4; band-gap energy, Eg=2.3 eV) as the photocathode. The Cu3PS4 crystals were grown by chemical vapor transport with halogen as the transport agent. The thermodynamics of the photoinsertion reaction of copper into Cu3PS4 electrodes was investigated, determining a composition-voltage diagram in the dark and under illumination. In photoelectrochemical cells the kinetics of the photoinsertion reaction was studied. Energy-converting photoinsertion cells could be realized with suitable counterelectrodes. The principles of energy-storing photoinsertion cells are discussed together with efficiency limitations and electrode arrangements that may overcome these difficulties.

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ABSTRACT:The synthesis of dark brown poly(2,5-furan-diylvinylene) (1) via aldol condensation reaction of 5-methylfuran-2-carbaldehyde as an one pot reaction yields an organic semiconductor which has long-lasting stability in the presence of air and water (tested over 10 years). Decolorization (decomposition) was observed only under long-time illumination. The reaction products were characterized by IR-, 1 H NMR-, mass-spectrometry and elemental analysis. Polymer 1 can be oxidized (doped) with Lewis acids such as iodine, AsF 5 and FeCl 3 . The values of the electrical conductivity range from 10-8