jp004411d_si_001.pdf (42.32 kB)
Pseudohalogens for Dye-Sensitized TiO2 Photoelectrochemical Cells
journal contribution
posted on 2001-06-28, 00:00 authored by Gerko Oskam, Bryan V. Bergeron, Gerald J. Meyer, Peter C. SearsonIn this paper, we report on the preparation and characterization of two pseudohalogen redox couples for
dye-sensitized TiO2 photoelectrochemical cells. The equilibrium potentials of the (SeCN)2/SeCN- and (SCN)2/SCN- couples are respectively 0.19 and 0.43 V more positive than for the I3-/I- couple, providing the
opportunity to determine the influence of the redox potential on the open circuit photovoltage. With the
sensitizer cis-Ru(dcb)2(NCS)2 (N3), the incident photon-to-current conversion efficiency was 20% for the
(SeCN)2/SeCN- couple and 4% for the (SCN)2/SCN- 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- > SeCN- > SCN-. The effects of the redox potential
on open circuit photovoltage were determined by independent measurement of the dependence of the sensitized
TiO2 working electrode and the platinum counter electrode potentials on the cell voltage.