Labeling Co-Sensitizer Dye for XPS Quantification in Coadsorption Dye-Sensitized Solar Cells

Abstract

Quantifying the coadsorption of dye molecules on nanoporous TiO₂ is difficult because of the complex adsorption structure between the dye and TiO₂ surface. D131 dye absorbs strongly in the ultraviolet region and is a common co-sensitizer for dye-sensitized solar cells. In this study, we showed that Cl-terminated D131 dye coadsorbed with a Ru complex on nanoporous TiO₂ can be used as a labeling compound to quantify coadsorption systems by X-ray photoelectron spectroscopy (XPS). Cl-terminated D131 alone and Cl-terminated D131 and N719 coadsorbed on nanoporous TiO₂ were measured with XPS. The Cl atoms were quantified by the peak intensity ratio of the Cl 1s and Ti 2p peaks. In the Cl-terminated D131 + N719 coadsorption system, the amount of Cl-terminated D131 dye adsorbed decreased by about 44% for the 1:1 mixture. Our technique could also be used to quantify other dyes in co-sensitizer systems, such as black dye and N3 dye. [DOI: 10.1380/ejssnt.2014.63]