6533b82bfe1ef96bd128df73

RESEARCH PRODUCT

Electron Transfer from the Singlet and Triplet Excited States of Ru(dcbpy)2(NCS)2into Nanocrystalline TiO2Thin Films

Jouko Korppi-tommolaVilly SundströmJani KallioinenArkady YartsevGabor Benkö

subject

Electron transferIntersystem crossingAbsorption spectroscopyChemistryExcited statePicosecondSinglet fissionMaterials ChemistrySinglet statePhysical and Theoretical ChemistryAtomic physicsTriplet stateSurfaces Coatings and Films

description

Time-resolved absorption spectroscopy was used to study the femtosecond and picosecond time scale electron injection from the excited singlet and triplet states of Ru(dcbpY)(2)(NCS)(2) (RuN3) into titanium dioxide (TiO2) nanocrystalline particle film in acetonitrile. The fastest resolved time constant of similar to30 fs was shown to reflect a sum of two parallel ultrafast processes, nonergodic electron transfer (ET) from the initially excited singlet state of RuN3 to the conduction band of TiO2 and intersystem crossing (ISC). The branching ratio of 1.5 between the two competing processes gives rate constants of 1/50 fs(-1) for ET and 1/75 fs(-1) for ISC. Following the ultrafast processes, a minor part of the electron injection (40%) occurs from the thermalized triplet state of RuN3 on the picosecond time scale. The kinetics of this slower phase of electron injection is nonexponential and can be fitted with time constants ranging from similar to1 to similar to60 ps.

yearjournalcountryeditionlanguage
2002-04-05The Journal of Physical Chemistry B
https://doi.org/10.1021/jp0143443