Jump to main content
Jump to site search

Issue 1, 2011
Previous Article Next Article

New molecular design of donor-π-acceptor dyes for dye-sensitized solar cells: control of molecular orientation and arrangement on TiO2 surface

Author affiliations

Abstract

A series of benzofuro[2,3-c]oxazolo[4,5-a]carbazole-type fluorescent dyes OH1, OH2, OH4, OH7, and OH17 with carboxyl groups on different positions of a chromophore skeleton are synthesized and applied to dye-sensitized solar cells (DSSCs) as a new class of donor-π-acceptor (D-π-A) photosensitizers. In the dye OH1, a carboxyl group acts as not only the anchoring group for attachment on TiO2 surface but also the electron acceptor. For OH2, OH4, and OH7, on the other hand, a carboxyl group is an anchoring group, but the electron acceptor is not a carboxyl group but a cyano group. The dye OH17 has two carboxyl groups, which are located at the same positions as those of OH1 and OH7. The absorption and fluorescence spectra and cyclic voltammograms of these fluorescent dyes resemble very well, showing a negligible influence of the position of carboxyl group on photophysical and electrochemical properties of these dyes. When these dyes are used in DSSCs, however, their photovoltaic performances differ considerably. In order to elucidate the difference in the DSSC performance among the five dyes, kinetics of the electron injection from the conduction band of TiO2 to dye cation and to I3 ions in solution were studied by employing the transient absorption spectroscopy and the transient photovoltage technique, respectively. It is found that the charge recombination rate for OH2 is similar to that of OH1 and is much slower than those of OH4 and OH17, consistent with the high short-circuit photocurrent densities for OH1 and OH2. On the basis of the MO calculations (AM1 and INDO/S) and the charge recombination kinetics, the differences of the photovoltaic performances among the five dyes are discussed from the viewpoint of configuration of the dyes adsorbed on TiO2 surface, and a new molecular design for D-π-A dye sensitizers based on a control of molecular orientation and arrangement of dye adsorbed on TiO2 surface is proposed.

Graphical abstract: New molecular design of donor-π-acceptor dyes for dye-sensitized solar cells: control of molecular orientation and arrangement on TiO2 surface

Back to tab navigation

Publication details

The article was received on 26 Jul 2010, accepted on 03 Sep 2010 and first published on 11 Oct 2010


Article type: Paper
DOI: 10.1039/C0NJ00585A
New J. Chem., 2011,35, 111-118

  •   Request permissions

    New molecular design of donor-π-acceptor dyes for dye-sensitized solar cells: control of molecular orientation and arrangement on TiO2 surface

    Y. Ooyama, Y. Shimada, S. Inoue, T. Nagano, Y. Fujikawa, K. Komaguchi, I. Imae and Y. Harima, New J. Chem., 2011, 35, 111
    DOI: 10.1039/C0NJ00585A

Search articles by author

Spotlight

Advertisements