Polydiacetylene/titania nanocomposites for dye-sensitized photovoltaic applications .

摘要

This dissertation research involves the novel development of polydiacetyene/TiO2 nanocomposites for dye-sensitized photovoltaic applications. First of all, it has been determined that diacetylene can be in-situ topochemically polymerized within nanoporous TiO2 films under visible light irradiation (violet-blue). The red shift of the photopolymerization wavelength can be attributed to the photo sensitization effect of TiO 2 upon photoexcitation. When TiO2 is coated with some ruthenium dyes, the polymerization can be induced in the green-yellow region. Morphology characterization via scanning electron microscopy indicates that in the absence of dye the photosensitized polymerization occurs at the interface of TiO 2 and diacetylene. Apart from TiO2, ZnO also demonstrates the photosensitization effect on diacetylene polymerization. These realizations could have a significant impact on the optimization and application of polydiacetylene (PDA) in electronic and photonic devices.; PDA has highly ordered and conjugated backbones, resulting in high charge carrier mobilities in the crystalline state. In this research, two types of carboxylated diacetylene monomers have been studied for their potential photovoltaic applications in solid-state dye-sensitized solar cells. The results show that the in-situ prepared PDA can act as a hole transporting material, but not a light sensitizer. Proof-of-concept efficiencies over 1% have been measured under simulated AM 1.5 illumination (100 mW/cm2). Some investigations toward inhibition of charge recombination have also been made but optimization is needed for better overall performance. A future breakthrough may lie in overcoming the limitations posed by parasitic absorption and long-range disorder of PDA within the nanoporous TiO2 film.