Excited-state deactivation of ruthenium(II) polypyridyl chromophores bound to nanocrystalline TiO{sub 2} mesoporous thin films
- Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Chemistry
There exists much current interest in developing a detailed understanding of photosensitized electron-transfer processes that occur on the surfaces of semiconductors. Sensitization allows the photoresponse of large band gap semiconductors to be extended into the visible region. Exploitation of sensitized materials in efficient photoelectrochemical cells represents an attractive molecular approach for the conversion of solar energy into electricity. Excitation of Ru(deeb)(bpy){sub 2}{sup 2+}, bis(2,2{prime}-bipyridine)(2,2{prime}-bipyridine-4,4{prime}-diethylester)ruthenium(II) hexafluorophosphate, bound to nanocrystalline TiO{sub 2} thin films and immersed in an acetonitrile bath at 25 C under an argon atmosphere, results in the formation of a species, the transient spectral characteristics for which are, consistent with a metal-to-ligand charge transfer, MLCT, excited state. The spectrum decays by kinetics that are inconsistent with a simple first-order process. Modeling of the data as a function of irradiance has been accomplished assuming parallel unimolecular and bimolecular excited-state deactivation processes. The quantum yield for excited state formation depends on the excitation irradiance, consistent with triplet-triplet annihilation processes that occur with k {ge} 1 {times} 10{sup 8} s{sup {minus}1}.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- OSTI ID:
- 680002
- Report Number(s):
- CONF-980314-; ISSN 0743-7463; TRN: IM9941%%43
- Journal Information:
- Langmuir, Vol. 15, Issue 3; Conference: American Chemical Society (ACS) meeting, Dallas, TX (United States), 26 Mar - 2 Apr 1998; Other Information: PBD: 2 Feb 1999
- Country of Publication:
- United States
- Language:
- English
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