Low-temperature oxygen plasma treatment of TiO 2 film for enhanced performance of dye-sensitized solar cells

Low-temperature oxygen plasma treatment of TiO 2 film for enhanced performance of dye-sensitized solar cells

The effects of low-temperature O 2 plasma treatment of a TiO 2 film are studied with the objective of improving the performance of dye-sensitized solar cells (DSSCs). X-ray photoelectron spectra (XPS) reveal that the ratio of titanium dioxide to titanium sub-oxides is increased in the O 2 plasma-tre...

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Bibliographic Details
Published in:Journal of power sources 2008, Vol.175 (2), p.914-919
Main Authors: Kim, Youngsoo, Yoo, Beom Jin, Vittal, R., Lee, Yeonhee, Park, Nam-Gyu, Kim, Kang-Jin
Format: Article
Language:eng
Subjects:
Conversion efficiency
Dye-sensitized TiO 2 solar cell
Oxygen plasma
Oxygen vacancy
Short-circuit photocurrent
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Summary:The effects of low-temperature O 2 plasma treatment of a TiO 2 film are studied with the objective of improving the performance of dye-sensitized solar cells (DSSCs). X-ray photoelectron spectra (XPS) reveal that the ratio of titanium dioxide to titanium sub-oxides is increased in the O 2 plasma-treated TiO 2 film, compared with that of the untreated TiO 2 film. This increase suggests that the oxygen vacancies in the film are effectively reduced. The near-edge X-ray absorption fine structure (NEXAFS) spectra results agree with the XPS result. It is proposed that there is a correlation between the shifts of the peaks in the NEXAFS spectra and the adsorption of N719 dye on the TiO 2 particles. A DSSC having an O 2 plasma-treated, 4 μm thick TiO 2 film electrode renders a short-circuit photocurrent of 7.59 mA cm −2, compared with 6.53 mA cm −2 for a reference cell with an untreated TiO 2 electrode of the same thickness. As a result of these changes, the solar-to-electricity conversion efficiency of the O 2 plasma-treated cell is found to be 4.0% as compared with 3.5% for the untreated cell. This improvement in the performance is rationalized on the basis of increased N719 dye adsorption on to the TiO 2, due to the reduction in the number of oxygen vacancies caused by the oxygen plasma treatment.
ISSN:0378-7753
1873-2755