H. Imahori (Kyoto University)
Recently we have developed aromatic ring-fused, unsymmetrically pi-elongated porphyrins (i.e., naphthalene-fused and quinoxaline-fused porphyrins) that showed broadened, and red-shifted light absorption properties compared to the corresponding porphyrin references, resulting in the power conversion efficiencies of 4.1% and 6.3%, respectively. As demonstrated for other sensitizers in DSSCs, introduction of both electron-donating and electron-withdrawing substituents to a core of pi system would be appealing for the modulation of the light-harvesting properties of sensitizers. In this talk I will present our recent advance in porphyrin-sensitized solar cells.
1-10 In particular, I will focus on novel push-pull porphyrins for porphyrin-sensitized solar cells.
1-10 For instance, we synthesized for the first time a push-pull porphyrin dye bearing two diarylamino groups and two carboxyphenylethynyl groups as electron-donating and electron-withdrawing anchoring groups, respectively. The absorption spectrum displayed broad and red-shifted absorption, achieving panchromic light-harvesting in visible and NIR regions. Introduction of multiple push-pull groups into
meso-positions is a promising strategy for the rational design of porphyrin sensitizers for light-harvesting applications. The preliminary photovoltaic performance is moderate (3.0%), but the extensive photocurrent generation matches with the excellent light-harvesting ability. Further modulation of the photovoltaic properties of porphyrin DSSCs will be possible by suitable selection of electron-donating and electron-withdrawing groups as well as introduction of the substituents into the porphyrin core.
[1] H. Imahori, T. Umeyama, and S. Ito, Acc. Chem. Res. 42, 1809 (2009).
[2] H. Imahori, S. Kang, H. Hayashi, M. Haruta, H. Kurata, S. Isoda, S. E. Canton, Y. Infahsaeng, A. Kathiravan, T. Pascher, P. Chabera, A. P. Yartsev, and V. Sundström, J. Phys. Chem. A, 115, 3679 (2011).
[3] H. Imahori, H. Iijima, H. Hayashi, Y. Toude, T. Umeyama, Y. Matano, and S. Ito, ChemSusChem, 4, 797 (2011).
[4] M. Simon, H. Iijima, Y. Toude, T. Umeyama, Y. Matano, S. Ito, N. V. Tkachenko, H. Lemmetyinen, and H. Imahori, J. Phys. Chem. C, 115, 14415 (2011).
[5] H. Imahori, T. Umeyama, K. Kurotobi, and Y. Takano, Chem. Commun. (Feature Article), 48, 4032 (2012).
[6] H. Hayashi, A. S. Touchy, Y. Kinjo, Y. Toude, K. Kurotobi, T. Umeyama, Y. Matano, and H. Imahori, ChemSusChem, 6, 508 (2013).
[7] S. Ye, A. Kathiravan, H. Hayashi, Y. Tong, Y. Infahsaeng, P. Chabera, T. Pascher, A. P. Yartsev, S. Isoda, H. Imahori, and V. Sundström, J. Phys. Chem. C, 117, 6066 (2013).
[8] K. Kurotobi, K. Kawamoto, Y. Toude, Y. Fujimori, Y. Kinjo, S. Ito, Y. Matano, and H. Imahori, Chem. Lett., 42, 725 (2013).
[9] K. Kurotobi, Y. Toude, K. Kawamoto, Y. Fujimori, S. Ito, P. Chabera, V. Sundström, and H. Imahori, Chem. Eur. J., 19, 17075 (2013).
[10] T. Higashino and H. Imahori, Dalton Trans. (Perspective), in press.
