Co-sensitization of microporous TiO 2 electrodes with dye molecules and quantum-sized semiconductor particles

Abstract

The microporous titanium dioxide (TiO 2) film has been prepared on a conducting glass substrate. A seven-fold enhancement in energy conversion efficiency of the dye-sensitized solar cell was achieved by pre-depositing a closely packed TiO 2 thin film on the surface of the conducting glass. Moreover, FeS 2 particles were coated on TiO 2 electrode by chemical reaction of iron pentacarbonyl with sulfur in xylene. Both atomic force microscope (AFM) and photoelectric studies suggest that the FeS 2 quantum-sized particles play a dominate role in the photoelectric conversion of FeS 2/TiO 2 electrode, while the FeS 2 large particles have less or even no contribution to the photo-current. Furthermore, the TiO 2 electrode has been co-modified with phthalocyanine dye molecules and quantum-sized semiconductor particles. Co-sensitization of the TiO 2 electrode with CdSe particles and ZnTCPc dye molecules not only extends the photoresponse of CdSe/TiO 2 electrode further into red region, but also improve the quantum efficiency of photoelectric conversion. We believe that such a co-sensitization technique should be of general importance in designing novel solar energy conversion devices.