10.1021/jp004411d.s001 Gerko Oskam Gerko Oskam Bryan V. Bergeron Bryan V. Bergeron Gerald J. Meyer Gerald J. Meyer Peter C. Searson Peter C. Searson Pseudohalogens for Dye-Sensitized TiO<sub>2</sub> Photoelectrochemical Cells American Chemical Society 2001 pseudohalogen redox couples SeCN circuit photovoltage SCN platinum counter electrode potentials TiO NCS pseudohalogen redox couple Transient absorbance measurements 2001-06-28 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Pseudohalogens_for_Dye-Sensitized_TiO_sub_2_sub_Photoelectrochemical_Cells/3721971 In this paper, we report on the preparation and characterization of two pseudohalogen redox couples for dye-sensitized TiO<sub>2</sub> photoelectrochemical cells. The equilibrium potentials of the (SeCN)<sub>2</sub>/SeCN<sup>-</sup> and (SCN)<sub>2</sub>/SCN<sup>-</sup> couples are respectively 0.19 and 0.43 V more positive than for the I<sub>3</sub><sup>-</sup>/I<sup>-</sup> couple, providing the opportunity to determine the influence of the redox potential on the open circuit photovoltage. With the sensitizer <i>cis</i>-Ru(dcb)<sub>2</sub>(NCS)<sub>2</sub> (N3), the incident photon-to-current conversion efficiency was 20% for the (SeCN)<sub>2</sub>/SeCN<sup>-</sup> couple and 4% for the (SCN)<sub>2</sub>/SCN<sup>-</sup> couple. Transient absorbance measurements showed that the quantum yield for electron injection is independent of the pseudohalogen redox couple and that the regeneration rates of the dye decrease in the order I<sup>-</sup> > SeCN<sup>-</sup> > SCN<sup>-</sup>. The effects of the redox potential on open circuit photovoltage were determined by independent measurement of the dependence of the sensitized TiO<sub>2</sub> working electrode and the platinum counter electrode potentials on the cell voltage.