Far-red sensitizing octatrifluorobutoxy phosphorous triazatetrabenzocorrole: Synthesis, spectral characterization and aggregation studies

Novel phosphorous triazatetrabenzocorrole (4) bearing non-peripheral octatrifluorobutoxy groups was successfully synthesized, with an aim to develop potential far-red sensitizer for dye sensitized solar cells. The dye was characterized by 1H NMR, IR, mass, and UV–vis spectral techniques. It showed excellent solubility in majority of common organic solvents. Aggregation behavior of the dye 4 was investigated in several solvents with increasing dielectric constants. This dye-4 was found to be adsorbed on the nanoporous TiO2 via axial ligation. Further implication of structure of dye due to incorporation of CF3 group on the energy levels was evaluated by theoretical and experimental approaches. The intense far-red absorption of dye 4 including its excellent solubility and proper control of its energy levels makes it a promising candidate for its application as sensitizer in dye sensitized solar cells.