Abstract: Thiocyanato (4,4'-dimethy1-2,2-bipyridyl)(4'-phenylphosphonate-terpyridyl) ruthenium(Ⅱ) was prepared and characterized with respect to its absorption, luminecence, and emission lifetime. The new dye with phosphonate absorption group can act as efficient charge-transfer sensitizer for nanocrystalline TiO₂ film illustrated by the high quantum yield of charge injection from the excited dye to the conduction band of TiO₂. Nanocrystalline TiO₂ film coated with monolayer of the prepared dye harvests visible light efficiently with the maximum LHE of 89.5% at 503 nm, And thus fabricated sensitized TiO₂ solar cell have a light to electric energy conversion efficiency of 3.1%, with 0.66V open circuit photovoltage and 4.4 mA/cm² short-circuit photocurrent. Study on the photocurrent action spectrum of the new dye sensitized TiO₂ film shows that the absorption group of the sensitizer has a strong influence on the photoelectrical performance of the film electrode.

Key words: terpyridyl ruthenium, TiO₂ film, dye-sensitization