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Modulation of Electron Injection Dynamics of Ru‐Based Dye/TiO 2 System in the Presence of Three Different Organic Solvents: Role of Solvent Dipole Moment and Donor Number
Author(s) -
Mahanta Subrata,
Matsuzaki Hiroyuki,
Murakami Takurou N.,
Katoh Ryuzi,
Matsumoto Hajime,
Furube Akihiro
Publication year - 2015
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201402907
Subject(s) - chemistry , solvent , ultrafast laser spectroscopy , photochemistry , dipole , dimethylformamide , excited state , ruthenium , solvent effects , spectroscopy , singlet state , electron , organic chemistry , atomic physics , physics , quantum mechanics , catalysis
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.