Ru(II)-Bpy Complexes Bound to Nanocrystalline TiO2 Films through Phenyleneethynylene (OPE) Linkers: Effect of the Linkers Length on Electron Injection Rates
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- 作者：Mykhaylo Myahkostupov ; Piotr Piotrowiak ; Dong Wang ; Elena Galoppini
- 刊名：Journal of Physical Chemistry C
- 出版年：2007
- 出版时间：February 22, 2007
- 年：2007
- 卷：111
- 期：7
- 页码：2827 - 2829
- 全文大小：115K
- 年卷期：v.111,no.7(February 22, 2007)
- ISSN：1932-7455
文摘
Three rigid-rod Ru-bpy sensitizers with linkers made of an oligo(phenyleneethynylene) (OPE) bridge varyingin length (9.6-23.3 Å) and ending with an isophthalic acid anchroing unit were bound to TiO2 (anatase)nanoparticle films, and the photoinduced electron injection rates for all three compounds were studied byfemtosecond laser spectroscopy. The sensitized films were excited at 530 nm, in the MLCT region, and theinjection dynamics was probed in the 600-1000 nm range. The excited state for all three compounds (
~ 2
s in acetonitrile solution) was readily quenched upon binding to TiO2. All injection traces could be fittedwith bi-exponential decays on a measured timescale of 130 ps. Plots of the fast or slow component of theelectron injection time constants probed at 670 nm vs the spacer length yielded a very low value for theattenuation factor (
~ 0.04 Å-1). Although the dependence was weak, the length of the linker clearly resultedin slower injection rates. The weak and monotonic linker length dependence had not been observed withother rigid-rod models, demonstrating the importance of anchoring groups in the design of model compoundsfor electron transfer studies at the semiconductor interfaces.
~ 2s in acetonitrile solution) was readily quenched upon binding to TiO2. All injection traces could be fittedwith bi-exponential decays on a measured timescale of 130 ps. Plots of the fast or slow component of theelectron injection time constants probed at 670 nm vs the spacer length yielded a very low value for theattenuation factor ( ~ 0.04 Å-1). Although the dependence was weak, the length of the linker clearly resultedin slower injection rates. The weak and monotonic linker length dependence had not been observed withother rigid-rod models, demonstrating the importance of anchoring groups in the design of model compoundsfor electron transfer studies at the semiconductor interfaces.