(Invited) Pi-Extended Porphyrins: Synthesis, Functionalization and Applications in Dye-Sensitized Solar Cells

Abstract

pi-Extended porphyrins are of broad interest due to their unique combination of photophysical, optoelectronic, and physicochemical properties, and their potential applications in many areas ranging from biomedicine to organic electronics.1,2 In this talk, three series of beta-functionalized push-pull pi-extended porphyrins as sensitizers for dye-sensitized solar cells will be presented.3-5 Our studies show significant push-pull effects for these porphyrins. DFT calculations suggest that the inclusion of ethynylphenyl bridge between the donating group and the porphyrin core significantly segregate the frontier orbitals. It has also been found that dimethylaminophenyl group cause dye decomposition on solar cells. To solve the dye degradation problem, porphyrin dyes with tertiary arylamine groups serving as the donor groups were prepared. Our studies show that tertiary arylamine groups are able to stabilize the dyes adsorbed on the solar cells. Their photovoltaic performances were tested in dye-sensitized solar cells. In this talk, the synthesis and characterization of pentacene-fused (linearly conjugated) and pentaquinone-fused (cross-conjugated) porphyrin oligomers will also be presented.6 These pentacene-fused porphyrins are much more stable than their corresponding pentacene derivatives. The electronic absorption spectra and transit spectroscopy of these porphyrins indicate highly interactive multiple p-systems. The electronic and optical properties of these p-extended porphyrins were measured using UV-Vis spectroscopy, life-time and steady state fluorescence spectroscopy, and cyclic voltammetry. DFT calculations were also performed for these porphyrins.