C₆₀ Cluster as an Electron Shuttle in a Ru(II)-Polypyridyl Sensitizer-Based Photochemical Solar Cell

Abstract

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 C 60 clusters to separate the Ru(bpy) 2 (dcbpy) 2+ (Ru(II) complex) and I 3 - /I - couple to minimize the sensitizer−redox couple interactions. The C 60 -modified electrodes (viz., OTE/SnO 2 /Ru(II)/C 60 and OTE/TiO 2 /Ru(II)/C 60 ) delivered photocurrent with greater efficiency than did the SnO 2 and TiO 2 films modified with only a Ru(II) dye (viz., OTE/SnO 2 /Ru(II) and OTE/TiO 2 /Ru(II)). The luminescence quenching of Ru(II)* by I 3 -, which occurs with a rate constant of 1.9 × 10 10 M -1 s -1, is suppressed following the deposition of a layer of C 60 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.