Significant progress has been made on dye-sensitized solar cells sensitized by push-pull porphyrins in recent years.^1-3 Through installing push-pull groups at porphyrin meso-positions, exceptionally high power conversion efficiencies have been achieved.^{4, 5} In this presentation, we present the synthesis and characterization of a series of novel opp-dibenzoporphyrins, and their application as sensitizers for dye-sensitized solar cells. These porphyrin sensitizers are designed through installation of push (electron-donating) and pull (electron-withdrawing) groups at the porphyrin beta-positions. Significant push-pull effects were observed for these porphyrins. The effect of different conjugated spacers on the power conversion efficiency of these dyes was investigated. It was found that inclusion of ethynylphenyl bridge between the donating group and porphyrin core would segregate the frontier orbitals. Our data also show that conjugated bridges appear to play important roles in determining their power conversion efficiency. The electronic and optical properties of these pi-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.

Reference

1. T. Higashino and H. Imahori, Dalton Trans., 2015, 44, 448-463.

2. M. Urbani, M. Gratzel, M. K. Nazeeruddin and T. Torres, Chem. Rev., 2014, 114, 12330-12396.

3. L. L. Li and E. W. Diau, Chem. Soc. Rev., 2013, 42, 291-304.

4. A. Yella, H.-W. Lee, H. N. Tsao, C. Yi, A. K. Chandiran, M. K. Nazeeruddin, E. W.-G. Diau, C.-Y. Yeh, S. M. Zakeeruddin and M. Grätzel, Science, 2011, 334, 629-634.

5. S. Mathew, A. Yella, P. Gao, R. Humphry-Baker, B. F. Curchod, N. Ashari-Astani, I. Tavernelli, U. Rothlisberger, M. K. Nazeeruddin and M. Gratzel, Nat. Chem., 2014, 6, 242-247.