The Synthesis, Characterisation, Photophysical and Thermal Properties, and Photovoltaic Performance of 7-Coumarinoxy-4-Methyltetrasubstituted Metallophthalocyanines

The synthesis, characterisation, photophysical and thermal properties of 2(3), 9(10), 16(17), 23(24)-tetrakis(7-coumarinoxy-4-methyl)-phthalocyaninatozinc(II) (ZnPc-Coumarin) and 2(3), 9(10), 16(17), 23(24)-tetrakis(7-coumarinoxy-4-methyl)phthalocyaninatocobalt(II) (CoPc-Coumarin) are reported. The ground state absorbance of ZnPc-Coumarin shows molar extinction coefficients as high as 1.80 x 10(5) dm(3) mol(-1) cm(-1). The fluorescence spectrum and fluorescence quantum yields of compounds ZnPc-Coumarin and CoPc-Coumarin are also investigated. The photoluminescence decay of the two transition-metal complexes in DMF solution, in poly(methyl methacrylate) (PMMA), and on TiO2 films has been studied with time-resolved emission. This study shows that the electron transfer from the dye to TiO2 is through space. The thermal stability studies indicate that both of the two complexes are stable up to 390 degrees C. The ZnPc-Coumarin achieved a higher overall conversion efficiency than the reported SnPcCl2-Coumarin, InPcCl-Coumarin, and RuPcCl-Coumarin because of its slower charge recombination rate and faster electron injection from the dye to the conduction band of the conducting glass.