Efficient panchromatic sensitization of nanocrystalline TiO2 films by β-diketonato ruthenium polypyridyl complexes

Abstract

The β-diketonato Ru(II)-polypyridyl complexes, Ru(4,4′,4″-tricarboxy-2,2′:6′,2″-terpyridine)(1,1,1-trifluoropentane-2,4-dionato)(NCS) and Ru(4,4′,4″-tricarboxy-2,2′:6′,2″-terpyridine)(1,1,1-trifluoroeicosane-2,4-dionato)(NCS), when anchored to nanocrystalline TiO₂ films, achieve very efficient panchromatic sensitization over the whole visible range extending into the near IR region, yielding 70% incident photon to current conversion efficiencies (IPCE). The presence of long hydrocarbon substituents on the β-diketonato ligand helps to prevent surface aggregation of the sensitizer.