Nanocomposite TiO2 xerogel film for DSSC photoelectrode via simple modified sol-gel process

Conventional sol-gel processing was simply modified by using ethanol as a co-solvent for the preparation of nanocomposite TiO2 gel binder for Degussa P25 photoelectrode. Ethanol was found to significantly affect the terminal group on TiO2 surface and its hydrophobicity. These, in turn, result in the reduction in the particle size and also the agglomeration of the synthesized TiO2 particles in the gel. Both modified and conventional TiO2 gels were used as binder for P25 to make dye-sensitized solar cell (DSSC) photoelectrode. The two gels significantly reduced film cracking and improved film morphology. Moreover, the use of modified TiO2 gel for the preparation of photoelectrode also dramatically improves the efficiency of DSSC when compared with the conventional gel. Data from electrochemical impedance spectroscopy under illumination and in the dark clearly showed that the photoelectrode had better electron transportation and greater resistance to recombination processes. These characteristics explain the observed higher short circuit current density (J (sc)) and efficiency of the DSSC cell.