Hexagonal mesoporous titanium tetrasulfonates with large conjugated hybrid framework for photoelectric conversion

Abstract

Ordered hexagonal mesoporous titanium tetrasulfonate materials (CuPcS4-Ti) were synthesized through a hydrothermal process with the assistance of surfactant F127, by using the copper(II) phthalocyanine-tetrasulfonic acid tetrasodium salt (CuPcS4) as coupling molecules. It was confirmed by TEM, IR, UV-vis, TGA-DSC, and XRD analysis that the CuPcS4 groups were homogenously incorporated into the hybrid framework, and the synthesized materials could be stable to around 328 °C with the hybrid framework and ordered mesopores well-preserved. A high dye content of Ti/CuPcS4 molar ratio at around 50 was achieved, which could be useful in the photoelectric conversion applications. A novel model of isolated dye centers surrounded by semiconductor oligomers was set, which could effectively suppress the aggregation of dye molecules that may decrease the conversion efficiency in some traditional dye-sensitized solar cells. It was proved that the synthesized CuPcS4-Ti exhibited a relatively high conversion efficiency of 0.53%. It was very valuable to access such a high conversion efficiency by using low-cost and commercially available dye molecules instead of using the expensive unsymmetrical phthalocyanines synthesized by the time-consuming methods in the literature.