Highly asymmetrical porphyrins with enhanced push-pull character for dye-sensitized solar cells.

A porphyrin π-system has been modulated by enhancing the push-pull character with highly asymmetrical substitution for dye-sensitized solar cells for the first time. Namely, both two diarylamino moieties as a strong electron-donating group and one carboxyphenylethynyl moiety as a strong electron-withdrawing, anchoring group were introduced into the meso-positions of the porphyrin core in a lower symmetrical manner. As a result of the improved light-harvesting property as well as high electron distribution in the anchoring group of LUMO, a push-pull-enhanced, porphyrin-sensitized solar cell exhibited more than 10% power conversion efficiency, which exceeded that of a representative highly efficient porphyrin (i.

Triarylamine-substituted imidazole- and quinoxaline-fused push-pull porphyrins for dye-sensitized solar cells.

We have prepared a push-pull porphyrin with an electron-donating triarylamino group at the β,β'-edge through a fused imidazole group and an electron-withdrawing carboxyquinoxalino anchoring group at the opposite β,β'-edge (ZnPQI) and evaluated the effects of the push-pull structure of ZnPQI on optical, electrochemical, and photovoltaic properties. ZnPQI showed red-shifted Soret and Q bands relative to a reference porphyrin with only an electron-withdrawing group (ZnPQ), thus demonstrating the improved light-harvesting property of ZnPQI. The optical HOMO-LUMO gap was consistent with that estimated by DFT calculations.

Bisquinoxaline-fused porphyrins for dye-sensitized solar cells.

5,10,15,20-Tetrakis(2,4,6-trimethylphenyl)-6'-carboxylquinoxalino[2,3-b]quinoxalino[12,13-b']porphyrinatozinc(II) (ZnPBQ) is synthesized to evaluate the effects of π elongation of quinoxaline-fused porphyrins on the optical, electrochemical, and photovoltaic properties. ZnPBQ showed an intensified Soret band as well as red-shifted Soret and Q bands relative to 5,10,15,20-tetrakis(2,4,6-trimethylphenyl)-6'-carboxylquinoxalino[2,3-b]porphyrinatozinc(II) (ZnPQ), demonstrating the improved light-harvesting property of ZnPBQ. The optical and electrochemical HOMO-LUMO gaps were consistent with those estimated by DFT calculations.