1298
Electron Transfer Dynamics of Supramolecular Solar Cells
Department of Chemistry, University North Texas, 1155, Union Circle, #305070, Denton, TX 76203-5017, USA
The relation between energy positioning and adsorption geometry on the electron transfer dynamics of donor-acceptor photosynthetic model compounds immobilized mesoporous TiO2 surface will be presented. Novel Zn-porphyrin (ZnP) and Zn-phthalocyanine (ZnPc) electron-donor and fullerene (C60) electron-acceptor bearing photosynthetic model compounds are designed to build supramolecular dye-sensitized solar cells (DSSC). It has been found that the solar cell efficiencies normalized for surface coverage (ηrel) are affected by the molecular spacer connecting the porphyrin sensitizer to the TiO2 surface, orientation of the dye molecule, the sensitization conditions (solvent and time) and dye aggregation. Ultrafast transient absorption spectroscopy shows that the forward and reverse electron transfer rates are strongly dependent on the spacer and sensitization conditions. These results also indicate that the electron transfer between sensitizer and TiO2 occurs “through-space” rather than “through-molecular spacer”. Implications of these findings for optimized solar energy/fuel production, and future sensor/biosensor development will be discussed.