Electron transport in nanocrystalline TiO2 films sensitized with [NBu4]2 [cis-Ru(Hdcbpy)2(NCS)2] (N719; [NBu4]+ = tetrabutyl ammonium cation;: H2dcbpy=4,4′-dicarboxy-2,2′-bipyridine) and [NBu4]2[Ru(Htcterpy)(NCS)3] (B-dye; H3tcterpy=4,4′,4"-tricarboxy-2,2′:6′,2"-terpyridine)

We compared electron transport in nanocrystalline TiO2 films sensitized with [NBu4](2)[cis-Ru(Hdcbpy)(2)(NCS)(2)] (N719; [NBu4](+) = tetrabutylammonium cation; H(2)dcbpy = 4,4'-dicarboxy-2,2'-bipyridine) and with [NBU4](2)[Ru(Htcterpy)-(NCS)(3)] (B-dye; H(3)tcterpy = 4,4',4"-tricarboxy-2,2':6',2"-terpyridine). The electron diffusion coefficient (D) and the electron lifetime (tau) of the N719-sensitized TiO2 were comparable to those of B-dye-sensitized TiO2, although the open circuit photovoltage (V-oc) of the solar cells based on N719-sensitized TiO2 was ca. 60mV larger than that of the solar cells based on B-dye-sensitized TiO2. We concluded that the energy of the conduction band edge (E-ch) of TiO2 sensitized with N719 was ca. 50mV more negative than that of TiO2 sensitized with B-dye.