The electron injection dynamics of dye-sensitized TiO2-based solar cells have been investigated to determine the effects of replacing the I3-/I- redox system by non-redox-active supporting electrolytes. TiO2 films were sensitized with Ru(dcbpy)2(NCS)2, where dcbpy = 4,4′-dicarboxylic acid-2,2′-bipyridine (the "N3" dye), and placed in contact with either M(C104) or M(I3-/I-) solutions (M = Li+ or (n-C4N9) 4N+);cells that contained I3-/I - were fully functional solar cells whose steady-state photocurrents were directly measured. In (n-C4H9)4N +-containing solutions, significant differences were observed between the measured kinetics when C104- was replaced by the redox-active I3-/I- system. In particular, a ps time scale loss of the metal-to-ligand charge-transfer excited-state of the N3 dye, associated with electron injection, that was observed in cells containing either LiClO4 or [(n-C4H9)4N] ClO4 was absent in fully functional solar cells that contained [(n-C4H9)4N]I/I2. These results underscore the importance of performing kinetics measurements on this class of solar cells under operational conditions if one is to obtain reliable correlations between the dynamics data and the steady-state performance metrics of the solar cell devices.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films