Strategy to Improve Photovoltaic Performance of DSSC Sensitized by Zinc Prophyrin Using Salicylic Acid as a Tridentate Anchoring Group

Three new zinc porphyrin dyes attached to ethynyl benzoic acid as an electron transmission and anchoring group have been designed, synthesized, and well-characterized. The performances of their sensitized solar cells have been investigated by optical, photovoltaic, and electrochemical methods. The photoelectric conversion efficiency of the solar cells sensitized by the dye with salicylic acid as an anchoring group demonstrated obvious enhancement when compared with that sensitized by the dye with carboxylic acid as an anchoring group. The density functional theory calculations and the electrochemical impedance spectroscopies revealed that tridentate binding modes could increase the efficiency of electron injection from dyes to the TiO2 nanoparticles by more electron pathways.