Pore-Filling of Spiro-OMeTAD in Solid-State Dye Sensitized Solar Cells: Quantification, Mechanism, and Consequences for Device Performance

I-Kang Ding, Nicolas Tétreault, Jérémie Brillet, Brian E. Hardin, Eva H. Smith, Samuel J. Rosenthal, Frédéric Sauvage, Michael Grätzel, Michael D. McGehee

Research output: Contribution to journalArticlepeer-review

236 Scopus citations


In this paper, the pore filling of spiro-OMeTAD (2,2′,7,7′- tetrakis-(N,N-di-p-methoxyphenylamine)9,9′-spirobtfIuorene) in mesoporous TiO2 films is quantified for the first time using XPS depth profiling and UV-Vis absorption spectroscopy. It is shown that spiro-OMeTAD can penetrate the entire depth of the film, and its concentration is constant throughout the film. We determine that in a 2.5-μm-thick film, the volume of the pores is 60-65% filled. The pores become less filled when thicker films are used. Such filling fraction is much higher than the solution concentration because the excess solution on top of the film can act as a reservoir during the spin coating process. Lastly, we demonstrate that by using a lower spin coating speed and higher spiro-OMeTAD solution concentration, we can increase the filling fraction and consequently the efficiency of the device. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA.
Original languageEnglish (US)
Pages (from-to)2431-2436
Number of pages6
JournalAdvanced Functional Materials
Issue number15
StatePublished - Aug 10 2009
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): KUS-C1-015-21
Acknowledgements: This publication was partially based on work supported the Center forAdvanced Molecular Photovoltaics (Award No KUS-C1-015-21), made byKing Abdullah University of Science and Technology (KAUST). It was alsopartially supported by the Office of Naval Research. I-K. Ding is supportedby a Chevron Stanford Graduate Fellowship. We thank Chuck Hitzman andDr. Michael Kelly for valuable discussions and experimental assistance withX-ray photoelectron spectroscopy and Dr. Brian O’Regan for giving us theidea of dissolving out spiro-OMeTAD from the pores. Jeremie Brilletreceived financial support from a Marie Curie Research Training Network,Hydrogen Project (MRTN-CT-2006-032474). Supporting Information isavailable online from Wiley InterScience or the author.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.


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