Sensitization of nano-porous films of TiO2 with santalin (red sandalwood pigment) and construction of dye-sensitized solid-state photovoltaic cells

Santalin, a pigment extracted from red sandalwood strongly surface complex to TiO2, sensitizing nano-porous film of TiO2 to the visible spectrum. Because of the stability of such films, dye-sensitized solid state photovoltaic cells of sandwich structure (nano-porous n-TiO2/santalin/p-type semiconductor) can be constructed by depositing p-CuI or p-CuCNS on santalin coated nano-porous films of TiO2. High stability of santalin complexed to TiO2 enables deposition of the p-type semiconductor without destroying the pigment layer. Light absorbed by the dye-molecules injects electrons into TiO2 and holes into CuI (or CuCNS) generating shea-circuit photocurrent similar to 6 mA/cm(2) and photovoltage similar to 450 mV at 800 W/m(2) simulated sunlight. (C) 1998 Elsevier Science S.A. All rights reserved.