Effects of Bridging Ligands on the Current−Potential Behavior and Interfacial Kinetics of Ruthenium-Sensitized Nanocrystalline TiO2 Photoelectrodes
We have shown that RuII(bpy)2(bpy-4-(xylyl) x -≡-phenyl-COOH)(PF6)2 (abbreviated Rux, where x = 0, 1 or 2 xylyl groups; bpy = 2,2‘-bipyridine) dyes can act as sensitizers for nanocrystalline TiO2 in functional photoelectrochemical cells under simulated solar illumination, albeit with low efficiencie...
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| Published in: | The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Molecules, spectroscopy, kinetics, environment, & general theory, 2003-05, Vol.107 (18), p.3379-3383 |
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| Main Authors: | , , , , , , |
| Format: | Article |
| Language: | eng |
| Online Access: | Get full text |
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| Summary: | We have shown that RuII(bpy)2(bpy-4-(xylyl) x -≡-phenyl-COOH)(PF6)2 (abbreviated Rux, where x = 0, 1 or 2 xylyl groups; bpy = 2,2‘-bipyridine) dyes can act as sensitizers for nanocrystalline TiO2 in functional photoelectrochemical cells under simulated solar illumination, albeit with low efficiencies. Both the short-circuit photocurrent density and the open-circuit voltage decreased as x was increased. Electron injection (106−108 s-1) was slightly faster for the x = 0 dye, but both recombination (10-15−10-13 cm3 s-1) and regeneration (104−106 s-1 for 10 mM I-) were slightly faster for the x = 2 dye. We suggest that the lack of distance dependence is due to the flexible one-carboxyl attachment to the surface resulting in the Ru−TiO2 electron-tunneling distance being very similar for x = 0, 1, and 2. For all of the Rux sensitizers, a relatively small potential was needed for generation of current in the dark, indicating that the reaction between electrons in TiO2 and the I3 -/I- electrolyte solution is as favorable for the Rux sensitizers as for unmodified TiO2 electrodes. |
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| ISSN: | 1089-5639 1520-5215 |