Electron transfer via organic dyes for solar conversion

The dye-sensitized solar cells are formed by a wide band gap semiconductor such as TiO(2), an organic dye coated on the semiconductor for light absorption, an electrolyte containing a suitable redox couple and a counterelectrode. In the present study, we investigated the functioning of black berry extract to sensitize TiO(2) for light absorption. TiO(2) thick films were screen-printed and sintered at 450 degrees C in air. It was sensitized with a fruit extract that contains anthocynin kind of organic dye, for example black berry extract. The black berry extract sensitized TiO(2) exhibited an increase in the photocurrent response indicating excess generation of photoelectrons due to light absorption by black berry extract. The photocurrent response in this case depends on parameters such as soaking time of TiO(2) in black berry juice, period of illumination, etc. The black berry extract was analyzed by optical absorption spectroscopy to characterize its absorption band. An absorption peak was observed at 517 nm, the intensity of which depends on the concentration of the black berry extract. (C) 1999 Elsevier Science B.V. All rights reserved.