Nanostructured Films of Conjugated Polyelectrolytes: Fundamental Studies and Application in Hybrid Solar Cells

Conjugated polyelectrolytes (CPEs) are semiconduciting organic polymers that feature polar/ionic solubilizing groups.  We have demonstrated that CPEs can be used as light absorbing sensitizers atop nanocrystalline TiO₂ in a dye-sensitized solar cell configuration leading to relatively efficient light-to-electrical power conversion.  We have observed interesting corrleations between polymer chain length (degree of polymerization, DP) and solution state (molecularly dissolved vs. aggregated) on the DSSC efficiency.  In order to better understand the interaction of CPEs with the metal-oxide interface, we have investigated the interaction of CPEs with single crystal TiO₂ interfaces using high resolution atomic force microscopy imaging and photocurrent spectroscopy.  Results of this work will be presented, with an emphasis on the fundamental factors that control the interaction and charge injection efficiency of CPEs at TiO₂ interfaces.