Enhanced charge transfer character of photoexcited states of dye sensitizer on the N719/TiO2 interface as revealed by electroabsorption spectra

Abstract Electroabsorption (E-A) spectra of (Bu 4 N) 2 [Ru(dcbpyH) 2 (NCS) 2 ] (N719) sensitized on TiO 2 nanoparticles are very different from those of the N719 solid film. In contrast with N719 fixed in a solid form, N719 adsorbed on TiO 2 shows a significant electric field effect on absorbance, indicating the strong interaction in the surface between N719 and TiO 2 . The magnitude of the change in electric dipole moment following absorption of N719 sensitized on TiO 2 is much greater than that of the sold film, suggesting that the interfacial charge transfer occurs following photoexcitation of N719 adsorbed on TiO 2 surface.