title: Modulation of Electron Injection Dynamics of Ru-Based Dye/TiO2 System in the Presence of Three Different Organic Solvents: Role of Solvent Dipole Moment and Donor Number.
abstract: In the present work, femtosecond transient absorption spectroscopy (fs-TAS) has been employed to investigate the electron injection efficiency (EIE) both from the singlet and triplet excited states of a well-known ruthenium dye (N719) to the conduction band (CB) of nanostructured TiO(2) in presence of three different organic solvents [γ-butylactone (GBL), 3-methoxypropionitrile (MPN), and dimethylformamide (DMF)] with different donor numbers (DNs) and dipole moments (DMs). The DM and DN of a solvent modulates the CB edge energy of TiO(2), and this effect reflects well in the fs-TAS results, which shows an EIE trend following the order GBL≥MPN≫DMF, that is, highest in GBL and lowest in DMF solvent environments. Fs-TAS results indicate a lower contribution of electron injection from both the singlet and triplet states in DMF, for which the dominant adsorption of DMF molecules on the TiO(2) surface seems to play an important role in the mechanism.
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1 2-10 Umezono, Tsukuba, Ibaraki 305-8568 (Japan).
authors.forename: Subrata
authors.initials: S
authors.lastname: Mahanta
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1 2-10 Umezono, Tsukuba, Ibaraki 305-8568 (Japan).
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Matsuzaki
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1 2-10 Umezono, Tsukuba, Ibaraki 305-8568 (Japan).
authors.forename: Takurou N
authors.initials: TN
authors.lastname: Murakami
authors.affiliation: Department of Chemical Biology and Applied Chemistry, College of Engineering, Nihon University, Koriyama, Fukushima 963-8642 (Japan).
authors.forename: Ryuzi
authors.initials: R
authors.lastname: Katoh
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1 2-10 Umezono, Tsukuba, Ibaraki 305-8568 (Japan).
authors.forename: Hajime
authors.initials: H
authors.lastname: Matsumoto
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1 2-10 Umezono, Tsukuba, Ibaraki 305-8568 (Japan). akihiro-furube@aist.go.jp.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Furube
mesh_terms: D004583:Electrons; D015394:Molecular Structure; D009930:Organic Chemicals; D009942:Organometallic Compounds / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013861:Thiocyanates / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*; D056928:X-Ray Absorption Spectroscopy
chemical_list: D009930:Organic Chemicals; D009942:Organometallic Compounds; D012997:Solvents; D013861:Thiocyanates; C506095:bis(2,2'-bipyridyl-4,4'-dicarboxylate)ruthenium(II) bis(tetrabutylammonium) bis(thiocyanate); C009495:titanium dioxide; D012428:Ruthenium; D014025:Titanium
keywords: DSSCs; dyes/pigments; electron injection efficiency; solvent effects; transient absorption spectroscopy