C60 cluster as an electron shuttle in a Ru(II)-polypyridyl sensitizer-based photochemical solar cell

The interaction between the excited sensitizer and the redox couple in a photochemical solar cell is an important factor that can decrease the photon-conversion efficiency. We have now employed C60 clusters to separate the Ru(bpy)2(dcbpy)2+ (Ru(II) complex) and I3-/I- couple to minimize the sensitizer−redox couple interactions. The C60-modified electrodes (viz., OTE/SnO2/Ru(II)/C60 and OTE/TiO2/Ru(II)/C60) delivered photocurrent with greater efficiency than did the SnO2 and TiO2 films modified with only a Ru(II) dye (viz., OTE/SnO2/Ru(II) and OTE/TiO2/Ru(II)). The luminescence quenching of Ru(II)* by I3-, which occurs with a rate constant of 1.9 × 1010 M-1 s-1, is suppressed following the deposition of a layer of C60 clusters. This paper presents a novel concept of employing a redox-active molecular assembly as an electron relay that greatly minimizes the interaction with the excited dye while maintaining the effectiveness of the regeneration cycle.