© 2015 American Chemical Society. Amphiphilic sensitizers are central to the function of dye-sensitized solar cells. It is known that the cell's performance depends on the molecular arrangement and the density of the dye on the semiconductor surface, but a molecular-level picture of the cell-electrolyte interface is still lacking. Here, we present subnanometer in situ atomic force microscopy images of the Z907 dye at the surface of TiO2 in a relevant liquid. Our results reveal changes in the conformation and the lateral arrangement of the dye molecules, depending on their average packing density on the surface. Complementary quantitative measurements on the ensemble of the film are obtained by the quartz-crystal microbalance with dissipation technique. An atomistic picture of the dye coverage-dependent packing, the effectiveness of the hydrophobic alkyl chains as blocking layer, and the solvent accessibility is obtained from molecular dynamics simulations. (Figure Presented).
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): KUS-C1-015-21
Acknowledgements: K.V. acknowledges funding from the Swiss National Science Foundation through the Ambizione Fellowship (PZ00P2_136941). U.R. acknowledges funding from the Swiss National Science Foundation via individual grant No. 200020-146645, the NCCRs MUST and MARVEL, and support from the Swiss National Computing Center (CSCS) and the CADMOS project for computing resources. M.G. thanks the European Research Council (ERC) for supporting part of this work under the advanced research grant (no. 247404) MESOLIGHT. H.A.H. acknowledges funding from the Swiss National Science Foundation (SNF). M.G. and N.T. acknowledge funding from the King Abdullah University of Science and Technology (KAUST, Award no. KUS-C1-015-21).
This publication acknowledges KAUST support, but has no KAUST affiliated authors.