Abstract:

First- and second-generation dendrimers (Ru3 and Ru6) have been synthesized, and their photophysical properties were investigated in solution and when adsorbed on the nanocrystalline TiO₂ surface. The performance of Ru3 and Ru6 as charge transfer photosensitizers in nanocrytalline TiO₂ based solar cells was also investigated. The best photovoltaic performance was obtained by the Ru3 based solar cell yielding a short circuit current of J_sc = 5.52 mA·cm⁻² and an open circuit voltage of V_oc = 626 mV, corresponding to an overall conversion efficiency of η = 1.80% that is approximately double the conversion efficiency of the reference compound Ru1 (η = 0.91%) and of the second generation dendrimer Ru6 (η = 0.95%). The particular efficiency of the first generation dendrimer, Ru3, is attributed to the better light-harvesting properties of the doped nanocrystalline TiO₂ film when compared to Ru1, whereas the poor performance of the second generation dendrimer, Ru6, is attributed to the uneven adsorption of all of the ruthenium moieties to the nanocrystalline TiO₂ surface at the same time.