Synthesis, Characterization and Electronic Properties of trans-[4-(Alkoxycarbonyl)phenyl]porphyrin-[RuII(bpy)3]2 Complexes or Boron-Dipyrrin Conjugates as Panchromatic Sensitizers for DSSCs

Two porphyrin‐based dyes were synthesized that incorporate two additional chromophores to absorb in a wider UV/Vis region. In the first dye, a porphyrin ring is linked through an amide bond to two [Ru(bpy)3]2+ units, forming a symmetric [Ru(bpy)3]‐porphyrin‐[Ru(bpy)3] {Por(COOH)2[Ru(bpy)3]2} system. The second porphyrin is trans substituted through a triple bond to the meso position with two boron dipyrrin (BDP) molecules {Por(COOH)2(BDP)2}. Both porphyrins bear two carboxylic groups capable of binding onto a TiO2 surface, with potential applications in dye‐sensitized solar cells (DSSCs). The title dyes were characterized by means of 1H and 13C NMR spectroscopy, elemental analysis, MALDI‐TOF, UV/Vis absorption and emission studies. New panchromatic dyes for dye‐sensitized solar cells (DSSCs) are reported. Photophysical studies of Por(COOMe)2[Ru(bpy)3]2 showed weak interactions between the porphyrin and [Ru(bpy)3] in the ground state. In the case of Por(COOH)2(BDP)2, interaction between the BDP moieties and the Zn porphyrin in the excited state were found. Both chromophores showed poor efficiencies in DSSC.