Characterization of pore-filling of spiro-MeOTAD in solid-state dye-sensitized solar cells and its consequence in device performance

Type
Conference Paper

Authors
Ding, I-Kang
Tétreault, Nicolas
Hardin, Brian E.
Smith, Eva H.
Grätzel, Michael
McGehee, Michael D.

KAUST Grant Number
KUS-C1-015-21

Online Publication Date
2009-08-27

Print Publication Date
2009-08-20

Date
2009-08-27

Abstract
In this paper, the pore filling of spiro-MeOTAD (2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenylamine)9, 9'-spirobifluorene) in mesoporous TiO2 films is quantified for the first time using XPS depth profiling and UVVis absorption spectroscopy. We show 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-•m-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

Citation
Ding I-K, Tétreault N, Hardin BE, Smith EH, Grätzel M, et al. (2009) Characterization of pore-filling of spiro-MeOTAD in solid-state dye-sensitized solar cells and its consequence in device performance. Organic Photovoltaics X. Available: http://dx.doi.org/10.1117/12.826408.

Acknowledgements
This publication was partially based on work supported the Center for Advanced Molecular Photovoltaics (Award No KUS-C1-015-21), made by King Abdullah University of Science and Technology (KAUST). It was also partially supported by the Office of Naval Research. I-K. Ding is supported by a Chevron Stanford Graduate Fellowship. We thank Chuck Hitzman and Dr. Michael Kelly for valuable discussions and experimental assistance with X-ray photoelectron spectroscopy and Dr. Brian O’Regan for giving us the idea of dissolving out spiro-OMeTAD from the pores.

Publisher
SPIE-Intl Soc Optical Eng

Journal
Organic Photovoltaics X

Conference/Event Name
Organic Photovoltaics X

DOI
10.1117/12.826408

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