Diffusion length in nanoporous TiO2 films under above-band-gap illumination

We determined the carrier diffusion lengths in TiO2 nanoporous layers of dye-sensitized solar cells by using scanning photocurrent microscopy using an ultraviolet laser. Here, we excited the carrier directly in the nanoporous layers where the diffusion lengths were found to 140 μm as compared to tha...

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Bibliographic Details
Published inAIP advances Vol. 4; no. 6; pp. 067106 - 067106-7
Main Authors Park, J. D., Son, B. H., Park, J. K., Kim, Sang Yong, Park, Ji-Yong, Lee, Soonil, Ahn, Y. H.
Format Journal Article
LanguageEnglish
Published Melville American Institute of Physics 01.06.2014
AIP Publishing LLC
Subjects
Diffusion layers
Diffusion length
Dye-sensitized solar cells
Illumination
Light
Photoelectric effect
Photoelectric emission
Photovoltaic cells
Titanium dioxide
Ultraviolet lasers
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Summary:We determined the carrier diffusion lengths in TiO2 nanoporous layers of dye-sensitized solar cells by using scanning photocurrent microscopy using an ultraviolet laser. Here, we excited the carrier directly in the nanoporous layers where the diffusion lengths were found to 140 μm as compared to that of visible illumination measured at 90 μm. The diffusion length decreased with increasing laser modulation frequency, in which we determined the electron lifetimes and the diffusion coefficients for both visible and UV illuminations. The diffusion lengths have been studied in terms of the sintering temperatures for both cells with and without binding molecules. We found a strong correlation between the diffusion length and the overall light-to-current conversion efficiency, proving that improving the diffusion length and hence the interparticle connections, is key to improving cell efficiency.
ISSN:2158-3226
2158-3226
DOI:10.1063/1.4881875