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

Abstract

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 short-circuit photocurrent ~6 mA/cm2 and photovoltage ~450 mV at 800 W/m2 simulated sunlight.