ORGN 5 |
Rigid linkers for TiO2 nanoparticles sensitization: Effect of conjugated and non-conjugated bridging units and distance dependence studies
| Elena Galoppini1, Qian Wei2, Dong Wang2, Piotr Piotrowiak2, and Mykhaylo Myahkostupov2. (1) Rutgers University, NJ, (2) Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ 07012 |
| Tripodal Ru(II) photosensitizers, have been used to study the effect of the conjugation of the bridge containing the chromophore in long-range electron transfer in TiO2 semiconductor nanoparticles thin films (Figure 1). The tripods have three COOMe anchoring groups that bind to the TiO2 surface and one rigid-rod bridge substituted with a Ru(II) complex (the sensitizer). The bridge in two tripods is made of two p-ethynylbenzene units (Ph-E-Ph-E). The bridge of a third has one saturated bicyclo[2.2.2]octylene unit in place of a benzene ring (Ph-E-Bco-E). The distance of the Ru center from the footprint all three tripods is 24 Å. The photophysical properties of the compounds in solution and bound to TiO2 thin films and the ultrafast laser spectroscopy study of the three tripods bound to TiO2 will be discussed. A comparison will be made with rigid rod linkers substituted with Ru complexes that are fully conjugated ((Ph-E)n )or contain the insulating bicyclo[2.2.2]octylene unit (Figure 2). The distance dependence of electron injection in rigid rods varying in length will be discussed. 
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