Photoinduced hole injection in semiconductor-coordination compound systems

A photoinduced electron injection from the excited photosensitizer to the conduction band is usually a key step of photosensitization of wide bandgap semiconductors. The significance of this process has been recognized especially in the case of titanium dioxide, when applied as a visible light active photocatalyst or as an anode material in dye-sensitized solar cells. An alternative mechanism of the semiconductor sensitization may involve a photoinduced hole injection into the valence band. This paper reviews semiconductor systems (NiO, copper compounds, doped diamond, TiO2) photosensitized by coordination compounds capable of a photoinduced hole injection into the valence band. The applicability of such systems for photocatalysis and photovoltaics is presented. (C) 2012 Elsevier B.V. All rights reserved.