Heterogeneous ruthenium dye adsorption on nano-structured TiO2 films for dye-sensitized solar cells

TiO2 particles of single-phase anatase nanocrystallites were prepared by the hydrolysis of titanium-tetraisopropoxide under acidic condition and characterized by XRD, FE-SEM, and BET analysis. The adsorption isotherms of dye molecule on TiO2 particles were obtained at three different temperatures (298.15, 313.15, 333.15 K) and the experimental data were correlated with Sips isotherm model. Also the isosteric enthalpies of dye adsorption were calculated by the Clausius–Clapeyron equation. The influence of heterogeneous adsorption of cis-bis(isothiocyanato)bis(2,2′-bipyridyl-4,4′-dicarboxylato)-ruthenium(II) bis-tetrabutylammonium dye (N719) on the energy conversion efficiency of solar cell was investigated on the basis of photocurrent–potential curves. The results showed that the conversion efficiency of dye-sensitized solar cell was highly dependent on the heterogeneous adsorption properties of N719 dye on TiO2 films.