IN-SITU INFRARED SPECTROSCOPIC ANALYSIS OF THE ADSORPTION OF RUTHENIUM(II) BIPYRIDYL DICARBOXYLIC-ACID PHOTOSENSITIZERS TO TIO2 IN AQUEOUS-SOLUTIONS

Internal reflection spectroscopy has been used to obtain the in situ i nfrared spectra of ruthenium(II) bipyridyl dicarboxylic acid photosens itiser species adsorbed to Degussa P25 and sol-gel TiO2 films from dil ute aqueous solutions. The spectra indicate that adsorption is via the carboxylate groups which bridge surface titanium ions. Adsorption iso therms and binding constants have been derived from the spectral data. The ruthenium(II) cyanato)-N,N'-bis(2,2'-bipyridyl-4,4'-dicarboxylic acid) complex, which is an efficient sensitiser, has the highest bindi ng constant. This suggests a link between the strength of surface bind ing and the solar energy conversion efficiency.