Effect of dye coverage on photo-induced electron injection efficiency in N719-sensitized nanocrystalline TiO2 films

The effect of dye coverage on the photo-induced electron injection efficiency in N719-sensitized nanocrystalline TiO2 films was studied by transient absorption spectroscopy. We evaluated the electron injection efficiency of films with several dye concentrations on the surface and found no significant difference between them. We also studied the suppression of the efficiency by the addition of tBP (4-tert-butylpyridine) and found that the effect of tBP was more pronounced for films with lower dye loading. This suggests that sensitizer dyes adsorbed densely onto the surface suppress the adsorption of tBP.