Comptes Rendus Chimie · 2005 · 12 citations · 5 references
The claim that ruthenium complexes attached to nanostructured TiO 2 can sustain 10 8 electron transfer cycles is in conflict with photocurrent imaging studies, which clearly show photoinduced degradation of solar cell efficiency. HPLC chromatographic studies of the cis -RuL 2 (SCN) 2 with L = 2,2-bipyridyl-4,4-dicarboxylatoacid (bpca) in solution and extracted from long-term operating solar cells were undertaken to identify the spectrum of possible photochemical products. While a dramatic increase of photochemical stability of the ruthenium complex when attached to TiO 2 nanoparticles is confirmed with respect to its photochemical reactivity in solution, photoelectrochemical products of the ruthenium complex can clearly be identified after one to a few months of solar cell operation under simulated solar light. The interpretation is that the ruthenium complex when adsorbed to TiO 2 nanoparticles is exposed to different surface states, which warrant different stability conditions to the oxidized ruthenium intermediate. .
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