title: Spacer and anchor effects on the electronic coupling in ruthenium-bis-terpyridine dye-sensitized TiO2 nanocrystals studied by DFT.
abstract: Structural and electronic properties of TiO2 nanoparticles sensitized with a set of Ru(II)(tpy)2 based dyes have been investigated using density functional theory (DFT) calculations combined with time-dependent (TD) DFT calculations. The effects of carboxylic and phosphonic acid anchor groups, as well as a phenylene spacer group, on the optical properties of the dyes and the electronic interactions in the dye-sensitized TiO2 nanoparticles have been investigated. Inclusion of explicit counterions in the modeling shows that the description of the environment is important in order to obtain a realistic interfacial energy level alignment. A comparison of calculated electronic coupling strengths suggests that both the nature of the anchor group and the inclusion of the phenylene spacer group are capable of significantly influencing electron-transfer rates across the dye-metal oxide interface.
authors.affiliation: Department of Quantum Chemistry, Uppsala University, Box 518, S-751 20 Uppsala, Sweden. Maria.Lundqvist@kvac.uu.se
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Lundqvist
authors.forename: Mattias
authors.initials: M
authors.lastname: Nilsing
authors.forename: Sten
authors.initials: S
authors.lastname: Lunell
authors.forename: Björn
authors.initials: B
authors.lastname: Akermark
authors.forename: Petter
authors.initials: P
authors.lastname: Persson