The synthesis, molecular structure and photophysical properties of 2, 9, 16, 23-tetrakis (7-coumarinoxy-4-methyl)-phthalocyanine sensitizer

• The ground state absorption suggests an intramolecular color matching is formed between phthalocyanine and coumarin components.
• The fluorescence decays of H2Pc-Cou under different conditions have been investigated.
• The DFT calculation indicates the twisted conformation of coumarin substituents.

The synthesis, characterization, calculation, photophysical and thermal properties of 2, 9, 16, 23-tetrakis (7-coumarinoxy-4-methyl)-phthalocyanine are reported in this paper. The ground state absorbance suggests that an intramolecular color matching is formed between phthalocyanine and coumarin components. The fluorescence quantum yield (ΦF) of H2Pc-Cou is lower than Std-ZnPc for the flexibile coumarin units quenching more excited singlet state. The photoluminescence decays of the complex in DMF solution, in poly (methyl methacrylate) (PMMA) and on TiO2 films have been investigated with time-resolved emission. Density functional theory modeling of the structure and energy calculations is made at the same time. The thermal stability studies indicate that the complex is stable up to 376 °C. The photophysical properties and energy levels proved it can be employed as sensitizers for DSSC applications.

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